This is mailfromd.info, produced by makeinfo version 6.7 from
mailfromd.texi.

Published by the Free Software Foundation, 51 Franklin Street, Fifth
Floor, Boston, MA 02110-1301 USA

   Copyright (C) 2005-2022 Sergey Poznyakoff

   Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.  A
copy of the license is included in the section entitled "GNU Free
Documentation License".
INFO-DIR-SECTION Email
START-INFO-DIR-ENTRY
* Mailfromd: (mailfromd).          General-purpose mail-filtering software.
* mailfromd: (mailfromd) Invocation.  Mail Filtering and Real-time Modification daemon.
* calloutd: (mailfromd) calloutd.  A Stand-Alone Callout Daemon.
* mfdbtool: (mailfromd) mfdbtool.  Database Management Tool.
* mtasim: (mailfromd) mtasim.      MTA simulator.
* pmult: (mailfromd) pmult.        Pmilter multiplexer program.
END-INFO-DIR-ENTRY

    









     Dedico aquest treball a Lluis Llach, per obrir els nous horitzons.
    
    


File: mailfromd.info,  Node: Filtering functions,  Next: Email processing functions,  Prev: I/O functions,  Up: Library

5.7 Filtering functions
=======================

This section describes functions that transform data using Mailutils
"filter pipes".  Filter pipe is a string defining data flow between
several "filters".  Each filter takes input, transforms it according to
certain rules and produces the transformed data on its output.  As in
shell, multiple filters are connected using pipe characters ('|').  For
example, the 'crlf' filter inserts a carriage return character before
each newline character.  A filter doing that kind of transformation is
defined as:

     "crlf"

   Another filter, 'base64', converts its input to a BASE64 encoded
string.  To transform each newline into carriage return + newline pair
and encode the resulting stream in BASE64, one would write:

     "crlf | base64"

   Some filters take one or more "arguments".  These are specified as a
comma-delimited list in parentheses after the filter name.  For example,
the 'linelen' filter limits the length of each output line to the given
number of octets.  The following filter pipe will limit the length of
base64 lines in the filter above to 62 octets:

     "crlf | base64 | linelen(62)"

   Many filters operate in two modes: "encode" and "decode".  By default
all MFL functions apply filters in encode mode.  The desired mode can be
stated explicitly in the filter string by using 'encode()' and
'decode()' functions.  They take a filter pipe line as their argument.
For example, the following will decode the stream produced by the
example filter above:

     "decode(base64 | crlf)"

   *Note Filters::, for a discussion of available filters and their
arguments.

 -- Built-in Function: string filter_string (string INPUT, string
          FILTER_PIPE)
     Transforms the string INPUT using filters in FILTER_PIPE and
     returns the result.  Example:

          set input "test\ninput\n"
          filter_string(input, "crlf|base64") => "dGVzdA0KaW5wdXQNCg=="

 -- Built-in Function: void filter_fd (number SRC_FD, number DST_FD,
          string FILTER_PIPE)
     Given two I/O descriptors, reads data from SRC_FD, transforms it
     using FILTER_PIPE and writes the result to descriptor DST_FD.

     Both descriptors must be obtained using functions described in
     *note I/O functions::.

* Menu:

* Filters::


File: mailfromd.info,  Node: Filters,  Up: Filtering functions

5.7.1 Filters and Filter Pipes
------------------------------

A "filter pipe" is a string consisting of filter invocations delimited
by pipe characters ('|').  Each invocation is a filter name optionally
followed by a comma-separated list of parameters.  Most filters can
operate in two modes: "encode" and "decode".  Unless specified
otherwise, filters are invoked in encode mode.  To change the mode, the
'encode' and 'decode' meta-filters are provided.  Argments to these
filters are filter pipes that will be executed in the corresponding
mode.

   The following Mailutils filters are available:

 -- Filter: 7bit
     In encode mode, converts its input into 7-bit ASCII, by clearing
     the 8th bit on each processed byte.

     In decode mode, it operates exactly as the 8bit filter, i.e.
     copies its input to the output verbatim.

     The filter takes no arguments.

 -- Filter: 8bit
 -- Filter: binary
     Copies its input to output verbatim.

 -- Filter: base64
 -- Filter: B
     Encodes or decodes the input using the 'base64' encoding.

     The only difference between 'BASE64' and 'B' is that, in encode
     mode, the former limits each ouput line length to 76 octets,
     whereas the latter produces a contiguous stream of base64 data.

     In decode mode, both filters operate exactly the same way.

 -- Filter: charset (CSET)
 -- Filter: charset (CSET, FALLBACK)
     A convenience interface to the 'iconv' filter, available for use
     only in the 'message_body_to_stream' function.  It decodes the part
     of a MIME message from its original character set, which is
     determined from the value of the 'Content-Type' header, to the
     destination character set CSET.  Optional FALLBACK parameter
     specifies the representation fallback to be used for octets that
     cannot be converted between the charater sets.  Its use is
     described in *Note iconv::.

     This filter is normally takes its input from the 'mimedecode'
     filter, as in:

          message_body_to_stream(fd, msg, 'mimedecode|charset(utf-8)')

     *Note mimedecode::, for a detailed discussion.

 -- Filter: crlf
 -- Filter: rfc822
     Converts line separators from LF (ASCII 10) to CRLF (ASCII 13 10)
     and vice-versa.

     In decode mode, translates each CRLF to LF. Takes no arguments.

     In encode mode, translates each LF to CRLF. If an optional argument
     '-n' is given, produces a "normalized" output, by preserving each
     input CRLF sequence untouched (otherwise such sequences will be are
     translated to CR CR LF).

 -- Filter: crlfdot
     In encode mode, replaces each LF ('\n' or ASCII 10) character with
     CRLF ('\r\n', ASCII 13 10), and "byte-stuffs" the output by
     producing an additional '.' in front of any '.' appearing at the
     beginning of a line in input.  Upon end of input, it outputs
     additional '.\r\n', if the last output character was '\n', or
     '\r\n.\r\n' otherwise.

     If supplied the '-n' argument, it preserves each CRLF input
     sequence untranslated (see the 'CRLF' above).

     In decode mode, the reverse is performed: each CRLF is replaced
     with a single LF byte, and additional dots are removed from
     beginning of lines.  A single dot on a line by itself marks the end
     of the stream and causes the filter to return EOF.

 -- Filter: dot
     In encode mode, "byte-stuffs" the input by outputting an additional
     dot ('.') in front of any dot appearing at the beginning of a line.
     Upon encountering end of input, it outputs additional '.\n'.

     In decode mode, the reverse is performed: additional dots are
     removed from beginning of lines.  A single dot on a line by itself
     (i.e.  the sequence '\n.\n') marks the end of the stream and causes
     the filter to return EOF.

     This filter doesn't take arguments.

 -- Filter: from
     Performs a traditional UNIX processing of lines starting with a
     'From' followed by a space character.

     In encode mode, each 'From ' at the beginning of a line is replaced
     by '>From '.

     In decode mode, the reverse operation is performed: initial
     greater-then sign ('>') is removed from any line starting with
     '>From '.

     The filter takes no arguments.

 -- Filter: fromrd
     MBOXRD-compatible processing of envelope lines.

     In encode mode, each 'From ' optionally preceded by any number of
     contiguous '>' characters and appearing at the beginning of a line
     is prefixed by another '>' character on output.

     In decode mode, the reverse operation is performed: initial
     greater-then sign ('>') is removed from any line starting with one
     or more '>' characters followed by 'From '.

 -- Filter: header
     This filter treats its input as a RFC-2822 email message.  It
     extracts its header part (i.e.  everything up to the first empty
     line) and copies it to the output.  The body of the message is
     ignored.

     The filter operates only in decode mode and takes no arguments.

 -- Filter: iconv (SRC, DST [, FALLBACK])
     Converts input from character set SRC to DST.  The filter works the
     same way in both decode and encode modes.

     It takes two mandatory arguments: the names of the input (SRC) and
     output (DST) charset.  Optional third argument specifies what to do
     when an illegal character sequence is encountered in the input
     stream.  Its possible values are:

     'none'
          Raise a 'e_ilseq' exception.

     'copy-pass'
          Copy the offending octet to the output verbatim and continue
          conversion from the next octet.

     'copy-octal'
          Print the offending octet to the output using the C octal
          conversion and continue conversion from the next octet.

     The default is 'copy-octal'.

     The following example creates a 'iconv' filter for converting from
     'iso-8859-2' to 'utf-8', raising the 'e_ilseq' exception on the
     first conversion error:

          iconv(iso-8859-2, utf-8, none)

 -- Filter: inline-comment
 -- Filter: inline-comment (STR, [options])
     In decode mode, the filter removes from the input all lines
     beginning with a given "inline comment sequence" STR.  The default
     comment sequence is ';' (a semicolon).

     The following options modify the default behavior:

     '-i, STR'
          Emit line number information after each contiguous sequence of
          removed lines.  The argument STR supplies an "information
          starter" - a sequence of characters which is output before the
          actual line number.

     '-r'
          Remove empty lines, i.e.  the lines that contain only
          whitespace characters.

     '-s'
          Squeeze whitespace.  Each sequence of two or more whitespace
          characters encountered on input is replaced by a single space
          character on output.

     '-S'
          A "whitespace-must-follow" mode.  A comment sequence is
          recognized only if followed by a whitespace character.  The
          character itself is retained on output.

     In encode mode the 'inline-comment' filter adds a comment-starter
     sequence at the beginning of each line.  The default
     comment-starter is ';' and can be changed by specifying the desired
     comment starter as the first argument.

     The only option supported in this mode is '-S', which enables the
     whitespace-must-follow mode, in which a single space character
     (ASCII 20) is output after each comment sequence.

 -- Filter: linecon
 -- Filter: linecon (-i, STR)
     Implements a familiar UNIX line-continuation facility.  The filter
     removes from itsinput stream any newline character immediately
     preceded by a backslash.  This filter operates only in decode mode.

     If given the arguments ('-i', STR), enables the "line number
     information facility".  This facility emits current input line
     number (prefixed with STR) after each contiguous sequence of one or
     more removed newline characters.  It is useful for implementing
     parsers which are normally supposed to identify eventual erroneous
     lines with their input line numbers.

 -- Filter: linelen (N)
     Limits the length of each output line to a certain number of
     octets.  It operates in encode mode only and requires a single
     parameter: the desired output length in octets.  This filter makes
     no attempt to analyze the lexical structure of the input: the
     newline caracters are inserted when the length of the output line
     reaches a predefined maximum.  Any newline characters present in
     the input are taken into account when computing the input line
     length.

 -- Filter: mimedecode
     This is a domain-specific filter available for use only with the
     'message_body_to_stream' function.  It decodes the part of a MIME
     message from whatever encoding that was used to store it in the
     message to a stream of bytes.  *Note mimedecode::.

 -- Filter: quoted-printable
 -- Filter: Q
     Encodes or decodes the input using the "quoted-printable" encoding.

 -- Filter: XML
     In encode mode, the 'xml' filter converts input stream (which must
     contain valid UTF-8 characters) into a form suitable for inclusion
     into a XML or HTML document, i.e.  it replaces '<', '>', and '&'
     with '&lt;', '&gt;', and '&amp;', correspondingly, and replaces
     invalid characters with their numeric character reference
     representation.

     In decode mode, a reverse operation is performed.

     The filter does not take arguments.


File: mailfromd.info,  Node: Email processing functions,  Next: Envelope modification functions,  Prev: Filtering functions,  Up: Library

5.8 Email processing functions.
===============================

 -- Built-in Function: number email_map (string EMAIL)
     Parses EMAIL and returns a bitmap, consisting of zero or more of
     the following flags:

     'EMAIL_MULTIPLE'
          EMAIL has more than one email address.

     'EMAIL_COMMENTS'
          EMAIL has comment parts.

     'EMAIL_PERSONAL'
          EMAIL has personal part.

     'EMAIL_LOCAL'
          EMAIL has local part.

     'EMAIL_DOMAIN'
          EMAIL has domain part.

     'EMAIL_ROUTE'
          EMAIL has route part.

     These constants are declared in the 'email.mf' module.  The
     function 'email_map' returns 0 if its argument is not a valid email
     address.

 -- Library Function: boolean email_valid (string EMAIL)
     Returns 'True' (1) if EMAIL is a valid email address, consisting of
     local and domain parts only.  E.g.:

          email_valid("gray@gnu.org") => 1
          email_valid("gray") => 0
          email_valid('"Sergey Poznyakoff <gray@gnu.org>') => 0

     This function is defined in 'email.mf' (*note Modules::).


File: mailfromd.info,  Node: Envelope modification functions,  Next: Header modification functions,  Prev: Email processing functions,  Up: Library

5.9 Envelope Modification Functions
===================================

Envelope modification functions set sender and add or delete recipient
addresses from the message envelope.  This allows MFL scripts to
redirect messages to another addresses.

 -- Built-in Function: void set_from (string EMAIL [, string ARGS])
     Sets envelope sender address to EMAIL, which must be a valid email
     address.  Optional ARGS supply arguments to ESMTP 'MAIL FROM'
     command.

 -- Built-in Function: void rcpt_add (string ADDRESS)
     Add the e-mail ADDRESS to the envelope.

 -- Built-in Function: void rcpt_delete (string ADDRESS)
     Remove ADDRESS from the envelope.

   The following example code uses these functions to implement a simple
alias-like capability:

     prog envrcpt
     do
        string alias dbget(aliasdb, $1, "NULL", 1)
        if alias != "NULL"
          rcpt_delete($1)
          rcpt_add(alias)
        fi
     done


File: mailfromd.info,  Node: Header modification functions,  Next: Body Modification Functions,  Prev: Envelope modification functions,  Up: Library

5.10 Header Modification Functions
==================================

There are two ways to modify message headers in a MFL script.  First is
to use header actions, described in *note Actions::, and the second way
is to use message modification functions.  Compared with the actions,
the functions offer a series of advantages.  For example, using
functions you can construct the name of the header to operate upon (e.g.
by concatenating several arguments), something which is impossible when
using actions.  Moreover, apart from three basic operations (add, modify
and remove), as supported by header actions, header functions allow to
insert a new header into a particular place.

 -- Built-in Function: void header_add (string NAME, string VALUE)
     Adds a header 'NAME: VALUE' to the message.

     In contrast to the 'add' action, this function allows to construct
     the header name using arbitrary MFL expressions.

 -- Built-in Function: void header_add (string NAME, string VALUE,
          number IDX)
     This syntax is preserved for backward compatibility.  It is
     equivalent to 'header_insert', which see.

 -- Built-in Function: void header_insert (string NAME, string VALUE,
          number IDX)
     This function inserts a header 'NAME: 'value'' at IDXth header
     position in the internal list of headers maintained by the MTA.
     That list contains headers added to the message either by the
     filter or by the MTA itself, but not the headers included in the
     message itself.  Some of the headers in this list are conditional,
     e.g.  the ones added by the 'H?COND?' directive in 'sendmail.cf'.
     MTA evaluates them after all header modifications have been done
     and removes those of headers for which they yield false.  This
     means that the position at which the header added by
     'header_insert' will appear in the final message will differ from
     IDX.

 -- Built-in Function: void header_delete (string NAME [, number INDEX])
     Delete header NAME from the envelope.  If INDEX is given, delete
     INDEXth instance of the header NAME.

     Notice the differences between this function and the 'delete'
     action:

       1. It allows to construct the header name, whereas 'delete'
          requires it to be a literal string.

       2. Optional INDEX argument allows to select a particular header
          instance to delete.

 -- Built-in Function: void header_replace (string NAME, string VALUE [,
          number INDEX])
     Replace the value of the header NAME with VALUE.  If INDEX is
     given, replace INDEXth instance of header NAME.

     Notice the differences between this function and the 'replace'
     action:

       1. It allows to construct the header name, whereas 'replace'
          requires it to be a literal string.

       2. Optional INDEX argument allows to select a particular header
          instance to replace.

 -- Library Function: void header_rename (string NAME, string NEWNAME[,
          number IDX])

     Defined in the module 'header_rename.mf'.
     Available only in the 'eom' handler.

     Renames the IDXth instance of header NAME to NEWNAME.  If IDX is
     not given, assumes 1.

     If the specified header or the IDX instance of it is not present in
     the current message, the function silently returns.  All other
     errors cause run-time exception.

     The position of the renamed header in the header list is not
     preserved.

     The example below renames 'Subject' header to 'X-Old-Subject':

          require 'header_rename'

          prog eom
          do
            header_rename("Subject", "X-Old-Subject")
          done

 -- Library Function: void header_prefix_all (string NAME [, string
          PREFIX])

     Defined in the module 'header_rename.mf'.
     Available only in the 'eom' handler.

     Renames all headers named NAME by prefixing them with PREFIX.  If
     PREFIX is not supplied, removes all such headers.

     All renamed headers will be placed in a continuous block in the
     header list.  The absolute position in the header list will change.
     Relative ordering of renamed headers will be preserved.

 -- Library Function: void header_prefix_pattern (string PATTERN, string
          PREFIX)

     Defined in the module 'header_rename.mf'.
     Available only in the 'eom' handler.

     Renames all headers with names matching PATTERN (in the sense of
     'fnmatch', *note fnmatches: Special comparisons.) by prefixing them
     with PREFIX.

     All renamed headers will be placed in a continuous block in the
     header list.  The absolute position in the header list will change.
     Relative ordering of renamed headers will be preserved.

     If called with one argument, removes all headers matching PATTERN.

     For example, to prefix all headers beginning with 'X-Spamd-' with
     an additional 'X-':

          require 'header_rename'

          prog eom
          do
            header_prefix_pattern("X-Spamd-*", "X-")
          done


File: mailfromd.info,  Node: Body Modification Functions,  Next: Message modification queue,  Prev: Header modification functions,  Up: Library

5.11 Body Modification Functions
================================

Body modification is an experimental feature of MFL.  The version 8.14
provides only one function for that purpose.

 -- Built-in Function: void replbody (string TEXT)
     Replace the body of the message with TEXT.  Notice, that TEXT must
     not contain RFC 822 headers.  See the previous section if you want
     to manipulate message headers.

     Example:

            replbody("Body of this message has been removed by the mail filter.")

     No restrictions are imposed on the format of TEXT.

 -- Built-in Function: void replbody_fd (number FD)
     Replaces the body of the message with the content of the stream FD.
     Use this function if the body is very big, or if it is returned by
     an external program.

     Notice that this function starts reading from the current position
     in FD.  Use 'rewind' if you wish to read from the beginning of the
     stream.

     The example below shows how to preprocess the body of the message
     using external program '/usr/bin/mailproc', which is supposed to
     read the body from its standard input and write the processed text
     to its standard output:

          number fd   # Temporary file descriptor

          prog data
          do
            # Open the temporary file
            set fd tempfile()
          done

          prog body
          do
            # Write the body to it.
            write_body(fd, $1, $2)
          done

          prog eom
          do
            # Use the resulting stream as the stdin to the mailproc
            # command and read the new body from its standard output.
            rewind(fd)
            replbody_fd(spawn("</usr/bin/mailproc", fd))
          done


File: mailfromd.info,  Node: Message modification queue,  Next: Mail header functions,  Prev: Body Modification Functions,  Up: Library

5.12 Message Modification Queue
===============================

Message modification functions described in the previous subsections do
not take effect immediately, in the moment they are called.  Instead
they store the requested changes in the internal "message modification
queue".  These changes are applied at the end of processing, before
'eom' stage finishes (*note Figure 3.1: milter-control-flow.).

   One important consequence of this way of operation is that calling
any MTA action (*note Actions::), causes all prior modifications to the
message to be ignored.  That is because after receiving the action
command, MTA will not call filter for that message any more.  In
particular, the 'eom' handler will not be called, and the message
modification queue will not be flushed.  While it is logical for such
actions as 'reject' or 'tempfail', it may be quite confusing for
'accept'.  Consider, for example, the following code:

     prog envfrom
     do
       if $1 == ""
         header_add("X-Filter", "foo")
         accept
       fi
     done

   Obviously, the intention was to add a 'X-Filter' header and accept
the message if it was sent from the null address.  What happens in
reality, however, is a bit different: the message is accepted, but no
header is added to it.  If you need to accept the message and retain any
modifications you have done to it, you need to use an auxiliary
variable, e.g.:

     number accepted 0
     prog envfrom
     do
       if $1 == ""
         header_add("X-Filter", "foo")
         set accepted 1
       fi
     done

   Then, test this variable for non-zero value at the beginning of each
subsequent handler, e.g.:

     prog data
     do
       if accepted
         continue
       fi
       ...
     done

   To help you trace such problematic usages of 'accept', 'mailfromd'
emits the following warning:

     RUNTIME WARNING near /etc/mailfromd.mf:36: `accept' causes previous
     message modification commands to be ignored; call mmq_purge() prior
     to `accept', to suppress this warning

   If it is OK to lose all modifications, call 'mmq_purge', as suggested
in this message.

 -- Built-in Function: void mmq_purge ()
     Remove all modification requests from the queue.  This function
     undoes the effect of any of the following functions, if they had
     been called previously: 'rcpt_add', 'rcpt_delete', 'header_add',
     'header_insert', 'header_delete', 'header_replace', 'replbody',
     'quarantine'.


File: mailfromd.info,  Node: Mail header functions,  Next: Mail body functions,  Prev: Message modification queue,  Up: Library

5.13 Mail Header Functions
==========================

 -- Built-in Function: string message_header_encode (string TEXT,
          [string ENC, string CHARSET])
     Encode TEXT in accordance with RFC 2047.  Optional arguments:

     ENC
          Encoding to use.  Valid values are 'quoted-printable', or 'Q'
          (the default) and 'base64', or 'B'.

     CHARSET
          Character set.  By default 'UTF-8'.

     If the function is unable to encode the string, it raises the
     exception 'e_failure'.

     For example:

          set string "Keld Jørn Simonsen <keld@dkuug.dk>"
          message_header_encode(string, "ISO-8859-1")
            => "=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@dkuug.dk>"

 -- Built-in Function: string message_header_decode (string TEXT,
          [string CHARSET])
     TEXT must be a header value encoded in accordance with RFC 2047.
     The function returns the decoded string.  If the decoding fails, it
     raises 'e_failure' exception.  The optional argument CHARSET
     specifies the character set to use (default - 'UTF-8').

          set string "=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@dkuug.dk>"
          message_header_decode(string)
           => "Keld Jørn Simonsen <keld@dkuug.dk>"

 -- Built-in Function: string unfold (string TEXT)
     If TEXT is a "folded" multi-line RFC 2822 header value, unfold it.
     If TEXT is a single-line string, return its unchanged copy.

     For example, suppose that the message being processed contained the
     following header:

          List-Id: Sent bugreports to
            <some-address@some.net>

     Then, applying 'unfold' to its value(1) will produce:

          Sent bugreports to <some-address@some.net>

   ---------- Footnotes ----------

   (1) For example:

     prog header
     do
       echo unfold($2)
     done


File: mailfromd.info,  Node: Mail body functions,  Next: EOM Functions,  Prev: Mail header functions,  Up: Library

5.14 Mail Body Functions
========================

 -- Built-in Function: string body_string (pointer TEXT, number COUNT)
     Converts first COUNT bytes from the memory location pointed to by
     TEXT into a regular string.

     This function is intended to convert the '$1' argument passed to a
     'body' handler to a regular MFL string.  For more information about
     its use, see *note body handler::.

 -- Built-in Function: bool body_has_nulls (pointer TEXT, number COUNT)
     Returns 'True' if first COUNT bytes of the string pointed to by
     TEXT contain ASCII NUL characters.

     Example:

          prog body
          do
            if body_has_nulls($1, $2)
              reject
            fi
          done


File: mailfromd.info,  Node: EOM Functions,  Next: Current Message Functions,  Prev: Mail body functions,  Up: Library

5.15 EOM Functions
==================

The following function is available only in the 'eom' handler:

 -- Built-in Function: void progress ()
     Notify the MTA that the filter is still processing the message.
     This causes MTA to restart its timeouts and allows additional
     amount of time for execution of 'eom'.

     Use this function if your 'eom' handler needs additional time for
     processing the message (e.g.  for scanning a very big MIME
     message).  You may call it several times, if the need be, although
     such usage is not recommended.


File: mailfromd.info,  Node: Current Message Functions,  Next: Mailbox functions,  Prev: EOM Functions,  Up: Library

5.16 Current Message Functions
==============================

 -- Built-in Function: number current_message ()
     This function can be used in 'eom' handlers only.  It returns a
     message descriptor referring to the current message.  *Note Message
     functions::, for a description of functions for accessing messages.

   The functions below access the headers from the current message.
They are available in the following handlers: 'eoh', 'body', 'eom'.

 -- Built-in Function: number current_header_count ([string NAME])

     Return number of headers in the current message.  If NAME is
     specified, return number of headers that have this name.

            current_header_count() => 6
            current_header_count("Subject") => 1

 -- Built-in Function: string current_header_nth_name (number N)

     Return the name of the Nth header.  The index N is 1-based.

 -- Built-in Function: string current_header_nth_value (number N)

     Return the value of the Nth header.  The index N is 1-based.

 -- Built-in Function: string current_header (string name [, number N])
     Return the value of the named header, e.g.:

            set s current_header("Subject")

     Optional second argument specifies the header instance, if there
     are more than 1 header of the same name, e.g.:

            set s current_header("Received", 2)

     Header indices are 1-based.

   All current_header function raise the 'e_not_found' exception if the
requested header was not found.


File: mailfromd.info,  Node: Mailbox functions,  Next: Message functions,  Prev: Current Message Functions,  Up: Library

5.17 Mailbox Functions
======================

A set of functions is provided for accessing mailboxes and messages
within them.  In this subsection we describe the functions for accessing
mailboxes.

   A mailbox is opened using 'mailbox_open' function:

 -- Built-in Function: number mailbox_open (string URL [, string MODE,
          string PERMS])
     Open a mailbox identified by URL.  Return a "mailbox descriptor": a
     unique numeric identifier that can subsequently be used to access
     this mailbox.

     The optional MODE argument specifies the access mode for the
     mailbox.  Its valid values are:

     Value          Meaning
     ------------------------------------------------------------------
     r              Open mailbox for reading.  This is the default.
     w              Open mailbox for writing.  If the mailbox does
                    not exist, it is created.
     rw             Open mailbox for reading and writing.  If the
                    mailbox does not exist, it is created.
     wr             Same as 'rw'.
     w+             Open mailbox for reading and writing.  If the
                    mailbox does not exist, it is created.
     a              Open mailbox for appending messages to it.  If
                    the mailbox does not exist, an exception is
                    signalled.
     a+             Open mailbox for appending messages to it.  If
                    the mailbox does not exist, it is created.

     The optional PERMS argument specifies the permissions to use in
     case a new file (or files) is created.  It is a comma-separated
     list of:

          [go](+|=)[wr]+

     The initial letter controls which users' access is to be set: users
     in the file's group ('g') or other users not in the file's group
     ('o').  The following character controls whether the permissions
     are added to the default ones ('+') or applied instead of them
     ('=').  The remaining letters specify the permissions: 'r' for read
     access and 'w' for write access.  For example:

          g=rw,o+r

   The number of mailbox descriptors available for simultaneous opening
is 64.  This value can be changed using the 'max-open-mailboxes' runtime
configuration statement (*note max-open-mailboxes: conf-runtime.).

 -- Built-in Function: number mailbox_messages_count (number NMBX)
     Return the number of messages in mailbox.  The argument NMBX is a
     valid mailbox descriptor as returned by a previous call to
     'mailbox_open'.

 -- Built-in Function: number mailbox_get_message (number MBX, number N)
     Retrieve Nth message from the mailbox identified by descriptor MBX.
     On success, the function returns a "message descriptor", an integer
     number that can subsequently be used to access that message (*note
     Message functions::).  On error, an exception is raised.

     Messages in a mailbox are numbered starting from 1.

 -- Built-in Function: void mailbox_close (number NMBX)
     Close a mailbox previously opened by 'mailbox_open'.

 -- Built-in Function: void mailbox_append_message (number NMBX, number
          NMSG)
     Append message NMSG to mailbox NMBX.  The message descriptor NSMG
     must be obtained from a previous call to 'mailbox_get_message' or
     'current_message' (*note current_message::).


File: mailfromd.info,  Node: Message functions,  Next: Quarantine functions,  Prev: Mailbox functions,  Up: Library

5.18 Message Functions
======================

The functions described below retrieve information from RFC822 messages.
The message to operate upon is identified by its "descriptor", an
integer number returned by the previous call to 'mailbox_get_message'
(*note mailbox_get_message: Mailbox functions.) or 'current_message'
(*note current_message::) function.  The maximum number of message
descriptors is limited by 1024.  You can change this limit using the
'max-open-messages' runtime configuration statement (*note
max-open-messages: conf-runtime.).

 -- Built-in Function: number message_size (number NMSG)
     Return the size of the message NMSG, in bytes.  _Notice_, that if
     NMSG refers to current message (*note current_message::), the
     returned value is less than the size seen by the MTA, because
     'mailfromd' recodes CR-LF sequences to LF, i.e.  removes carriage
     returns (ASCII 13) occurring before line feeds (ASCII 10.  To
     obtain actual message length as seen by the MTA, add the number of
     lines in the message:

            set actual_length message_size(nmsg) + message_lines(nmsg)

 -- Built-in Function: boolean message_body_is_empty (number NMSG)
     Returns 'true' if the body of message NMSG has zero size or
     contains only whitespace characters.  If the
     'Content-Transfer-Encoding' header is present, it is used to decode
     body before processing.

 -- Built-in Function: void message_close (number NMSG)
     Close the message identified by descriptor NMSG.

 -- Built-in Function: number message_lines (number NMSG)
     Return total number of lines in message NMSG.  The following
     relation holds true:

          message_lines(X) = message_body_lines(X)
                                   + message_header_lines(X) + 1

 -- Built-in Function: string message_read_line (number NMSG)
     Read and return next line from the message NMSG.  If there are no
     more lines to read, raise the 'eof' exception.

     Use 'message_rewind' to rewind the message stream and read its
     contents again.

 -- Built-in Function: void message_rewind (number NMSG)
     Rewind the stream associated with message referred to by descriptor
     NMSG.

 -- Built-in Function: number message_from_stream (number FD; string
          FILTER_CHAIN)
     Converts contents of the stream identified by FD to a mail message.
     Returns identifier of the created message.

     Optional FILTER_CHAIN supplies the name of a "Mailutils filter
     chain", through which the data will be passed before converting.
     See <http://mailutils.org/wiki/Filter_chain>, for a description of
     filter chains.

 -- Built-in Function: void message_to_stream (number FD, number NMSG;
          string FILTER_CHAIN)
     Copies message NSMG to stream descriptor FD.  The descriptor must
     be obtained by a previous call to 'open'.

     Optional FILTER_CHAIN supplies the name of a "Mailutils filter
     chain", through which the data will be passed before writing them
     to FD.  See <http://mailutils.org/wiki/Filter_chain>, for a
     description of filter chains.

* Menu:

* Header functions::
* Message body functions::
* MIME functions::
* Message digest functions::


File: mailfromd.info,  Node: Header functions,  Next: Message body functions,  Up: Message functions

5.18.1 Header functions
-----------------------

 -- Built-in Function: number message_header_size (number NMSG)
     Return the size, in bytes of the headers of message NMSG.  See the
     note to the 'message_size', above.

 -- Built-in Function: number message_header_lines (number NMSG)
     Return number of lines occupied by headers in message NMSG.

 -- Built-in Function: number message_header_count (number NMSG, [string
          NAME])
     Return number of headers in message NMSG.

     If NAME is supplied, count only headers with that name.

 -- Built-in Function: string message_find_header (number NMSG, string
          NAME [, number IDX])
     Return value of header NAME from the message NMSG.  If the message
     contains several headers with the same name, optional parameter IDX
     may be used to select one of them.  Headers are numbered from '1'.

     If no matching header is not found, the 'not_found' exception is
     raised.  If another error occurs, the 'failure' exception is
     raised.

     The returned string is a verbatim copy of the message contents
     (except for eventual CR-LF -> LF translation, see above).  You
     might need to apply the 'unfold' function to it (*note unfold: Mail
     header functions.).

 -- Built-in Function: string message_nth_header_name (number NMSG,
          number N)
     Returns the name of the Nth header in message NMSG.  If there is no
     such header, 'e_range' exception is raised.

 -- Built-in Function: string message_nth_header_value (number MSG,
          number N)
     Returns the value of the Nth header in message NMSG.  If there is
     no such header, 'e_range' exception is raised.

 -- Built-in Function: boolean message_has_header (number NMSG, string
          NAME [, number IDX])
     Return 'true' if message NMSG contains header with the given NAME.
     If there are several headers with the same name, optional parameter
     IDX may be used to select one of them.


File: mailfromd.info,  Node: Message body functions,  Next: MIME functions,  Prev: Header functions,  Up: Message functions

5.18.2 Message body functions
-----------------------------

 -- Built-in Function: number message_body_size (number NMSG)
     Return the size, in bytes, of the body of message NMSG.  See the
     note to the 'message_size', above.

 -- Built-in Function: number message_body_lines (number NMSG)
     Return number of lines in the body of message referred to by
     descriptor NMSG.

 -- Built-in Function: void message_body_rewind (number NMSG)
     Rewind the stream associated with the body of message referred to
     by descriptor NMSG.

     A call to 'message_body_read_line' (see below) after calling this
     function will return the first line from the message body.

 -- Built-in Function: string message_read_body_line (number NMSG)
     Read and return next line from the body of the message NMSG.  If
     there are no more lines to read, raise the 'eof' exception.

     Use 'message_body_rewind' (see above) to rewind the body stream and
     read its contents again.

 -- Built-in Function: void message_body_to_stream (number FD, number
          NMSG; string FILTER_PIPE)
     Copies the body of the message NSMG to stream descriptor FD.  The
     descriptor must be obtained by a previous call to 'open'.

     Optional FILTER_PIPE supplies a sequence of "Mailutils filters",
     through which the data will be passed before writing them to FD.
     *Note Filtering functions::, for a discussion of filter pipe
     syntax.

     In addition to filters described in *Note Filters::, two special
     filters are provided for use with this function: 'mimedecode' and
     'charset'.  The 'mimedecode' filter instructs the function to
     decode the message body by reverting the encoding specified by its
     'Content-Transfer-Encoding' header.  It is normally used as the
     very first filter in chain.  The 'charset' filter recodes the
     message body from it original character set to the character set
     specified as its argument.

     *Note mimedecode::, for a detailed discussion of this feature.


File: mailfromd.info,  Node: MIME functions,  Next: Message digest functions,  Prev: Message body functions,  Up: Message functions

5.18.3 MIME functions
---------------------

 -- Built-in Function: boolean message_is_multipart (number NMSG)
     Return 'true' if message NMSG is a multipart (MIME) message.

 -- Built-in Function: number message_count_parts (number NMSG)
     Return number of parts in message NMSG, if it is a multipart (MIME)
     message.  If it is not, return '1'.

     Use 'message_is_multipart' to check whether the message is a
     multipart one.

 -- Built-in Function: number message_get_part (number nmsg, number N)
     Extract Nth part from the multipart message NMSG.  Numeration of
     parts begins from '1'.  Return message descriptor referring to the
     extracted part.  Message parts are regarded as messages, so any
     message functions can be applied to them.

 -- Built-in Function: string message_content_type (number NMSG)
     Returns content type for the message NMSG.  The returned string is
     composed of content type and subtype, delimited by slash.

     If NMSG is not a multipart message, the function returns
     'text/plain'.

   Several functions are provided for decoding multi-part messages.
Such decoding is governed by 'Content-Transfer-Encoding' and
'Content-Type' headers of the message.  The 'Content-Transfer-Encoding'
header defines the method used to encode the message.  The value of
'Content-Type' header is used to determine the character set the body is
written in.

   Basic MIME decoding facilities are provided by the built-in function
'message_body_to_stream', described in the previous subsection.  To
instruct it to decode the content, pass it the FILTER_CHAIN argument
beginning with the word 'mimedecode'.  The usual sequence is:

     set fd open("> outfile")
     message_body_to_stream(fd, msg, "mimedecode")

   To ensure that the produced stream is represented in a specific
character set, use the 'charset' special filter.  Its argument is the
name of the character set to recode the text to:

     set fd open("> outfile")
     message_body_to_stream(fd, msg, "mimedecode|charset(utf-8)")

   The 'charset' filter takes also an optional second argument - a
"fallback" method, specifying what to do when an octet sequence is
encountered that cannot be represented in the requested character set.
Possible values for this argument are:

'none'
     Stop further conversion and signal the 'e_ilseq' exception.

'copy-pass'
     Copy the offending character to the output verbatim.

'copy-octal'
     Represent the offending character as a C octal sequence ('\NNN',
     where N is an octal digit).  This is the default.

   To decode a particular part of the message, first extract it using
the 'message_get_part' function.  Recall that message parts are messages
as well, and as such can be passed to 'message_body_to_stream'.  For
example, the following code fragment extracts all top-level parts of a
multi-part message to files named 'part.N':

     if message_is_multipart(msg)
       set n message_count_parts(msg)
       loop for set i 1, while i <= n, set i i + 1
       do
         set fd open("> part.%i")
         message_body_to_stream(fd, message_get_part(msg, i), "mimedecode")
         close(fd)
       done
     fi

   The 'mime.mf' module provides additional functions for decoding
multi-part messages:

 -- Library Function: number message_body_decode (number NMSG; string
          CHARSET, string FALLBACK)
     Decodes the body of the message (or message part) NMSG, optionally
     converting it to the given CHARSET.  The FALLBACK argument
     specifies what to do if a byte sequence cannot be converted to the
     specified character set.  *Note iconv fallback::, for a detailed
     discussion.

     The function returns a descriptor of the I/O stream that contains
     the decoded material.  *Note I/O functions:: for a discussion of
     functions available for reading from it.

 -- Library Function: number message_part_decode(number NMSG, number
          PART; string CHARSET, string FALLBACK)
     Decodes the body of the given part of a MIME message NMSG.  The
     argument PART is a 1-based index of the part in the message.
     Optional arguments CHARSET and FALLBACK have the same meaning as in
     'message_body_decode' (see above).

     Returns a descriptor of the I/O stream that contains the decoded
     material.

     This function is equivalent to:

          message_body_decode(message_get_part(NMSG, PART, CHARSET,
                              FALLBACK))


File: mailfromd.info,  Node: Message digest functions,  Prev: MIME functions,  Up: Message functions

5.18.4 Message digest functions
-------------------------------

"Message digests" are specially formatted messages that contain certain
number of mail messages, encapsulated using the method described in RFC
934.  Such digests are often used in mailing lists to reduce the
frequency of sending mails.  Messages of this format are also produced
by the "forward" function in most MUA's.

   The usual way to handle a message digest in MFL is to convert it
first to a MIME message, and then to use functions for accessing its
parts (*note MIME functions::).

 -- Built-in Function: number message_burst (number NMSG ; number FLAGS)
     Converts the message identified by the descriptor NMSG to a
     multi-part message.  Returns a descriptor of the created message.

     Optional argument FLAGS controls the behavior of the bursting
     agent.  It is a bitwise OR of error action and bursting flags.

     "Error action" defines what to do if a part of the digest is not in
     RFC822 message format.  If it is 'BURST_ERR_FAIL' (the default),
     the function will raise the 'e_format' exception.  If ONERR is
     'BURST_ERR_IGNORE', the improperly formatted part will be ignored.
     Finally, the value 'BURST_ERR_BODY' instructs 'message_burst' to
     create a replacement part with empty headers and the text of the
     offending part as its body.

     "Bursting flags" control various aspects of the agent behavior.
     Currently only one flag is defined, 'BURST_DECODE', which instructs
     the agent to decode any MIME parts (according to the
     'Content-Transfer-Encoding' header) it encounters while bursting
     the message.

   Parts of a message digest are separated by so-called "encapsulation
boundaries", which are in essence lines beginning with at least one dash
followed by a non-whitespace character.  A dash followed by a whitespace
serves as a "byte-stuffing" character, a sort of escape for lines which
begin with a dash themselves.  Unfortunately, there are mail agents
which do not follow byte-stuffing rules and pass lines beginning with
dashes unmodified into resulting digests.  To help handle such cases a
global variable is provided which controls how much dashes should the
line begin with for it to be recognized as an encapsulation boundary.

 -- Built-in variable: number burst_eb_min_length
     Minimal number of consecutive dashes an encapsulation boundary must
     begin with.

     The default is 2.

   The following example shows a function which saves all parts of a
digest message to separate disk files.  The argument ORIG is a message
descriptor.  The resulting files are named by concatenating the string
supplied by the STEM argument and the ordinal number (1-based) of the
message part.

     func burst_digest(number orig, string stem)
     do
       number msg message_burst(orig)
       number nparts message_count_parts(msg)

       loop for number i 1,
            while i <= nparts,
            set i i + 1
       do
         number part message_get_part(msg, i)
         number out open(sprintf('>%s%02d', stem, i))
         message_to_stream(out, part)
       done
       message_close(msg)
     done


File: mailfromd.info,  Node: Quarantine functions,  Next: SMTP Callout functions,  Prev: Message functions,  Up: Library

5.19 Quarantine Functions
=========================

 -- Built-in Function: void quarantine (string TEXT)
     Place the message to the quarantine queue, using TEXT as
     explanatory reason.


File: mailfromd.info,  Node: SMTP Callout functions,  Next: Compatibility Callout functions,  Prev: Quarantine functions,  Up: Library

5.20 SMTP Callout Functions
===========================

 -- Library Function: number callout_open (string URL)
     Opens connection to the callout server listening at URL.  Returns
     the descriptor of the connection.

 -- Library Function: void callout_close (number FD)
     Closes the connection.  FD is the file descriptor returned by the
     previous call to 'callout_open'.

 -- Library Function: number callout_do (number FD, string EMAIL [,
          string REST])
     Instructs the callout server identified by FD (a file descriptor
     returned by a previous call to 'callout_open') to verify the
     validity of the EMAIL.  Optional REST argument supplies additional
     parameters for the server.

     Possible return values:

     '0'
          Success.  The EMAIL is found to be valid.
     'e_not_found'
          EMAIL does not exist.
     'e_temp_failure'
          The email validity cannot be determined right now, e.g.
          because remote SMTP server returned temporary failure.  The
          caller should retry verification later.
     'e_failure'
          Some error occurred.

     The function will throw the 'e_callout_proto' exception if the
     remote host doesn't speak the correct callout protocol.

     Upon return, 'callout_do' modifies the following variables:

     'last_poll_host'
          Host name or IP address of the last polled SMTP server.

     'last_poll_greeting'
          Initial SMTP reply from the last polled host.

     'last_poll_helo'
          The reply to the 'HELO' ('EHLO') command, received from the
          last polled host.

     'last_poll_sent'
          Last SMTP command sent to the polled host.  If nothing was
          sent, 'last_poll_sent' contains the string 'nothing'.

     'last_poll_recv'
          Last SMTP reply received from the remote host.  In case of
          multi-line replies, only the first line is stored.  If nothing
          was received the variable contains the string 'nothing'.

   The "default callout server" is defined by the 'callout-url'
statement in the configuration file, or by the 'callout' statement in
the 'server milter' section (*note configuring default callout server::.
The following functions operate on that server.

 -- Built-in Function: string default_callout_server_url ()
     Returns URL of the default callout server.

 -- Library Function: number callout (string EMAIL)
     Verifies the validity of the EMAIL using the default callout
     server.


File: mailfromd.info,  Node: Compatibility Callout functions,  Next: Internet address manipulation functions,  Prev: SMTP Callout functions,  Up: Library

5.21 Compatibility Callout Functions
====================================

The following functions are wrappers over the callout functions
described in the previous section.  They are provided for backward
compatibility.

   These functions are defined in the module 'poll.mf', which you must
require prior to using any of them.

 -- Library Function: boolean _pollhost (string IP, string EMAIL, string
          DOMAIN, string MAILFROM)
     Poll SMTP host IP for email address EMAIL, using DOMAIN as 'EHLO'
     domain and MAILFROM as 'MAIL FROM'.  Returns 0 or 1 depending on
     the result of the test.  In contrast to the 'strictpoll' function,
     this function does not use cache database and does not fall back to
     polling MX servers if the main poll tempfails.  The function can
     throw one of the following exceptions: 'e_failure',
     'e_temp_failure'.

 -- Library Function: boolean _pollmx (string IP, string EMAIL, string
          DOMAIN, string MAILFROM)
     Poll MXs of the DOMAIN for email address EMAIL, using DOMAIN as
     'EHLO' domain and MAILFROM as 'MAIL FROM' address.  Returns 0 or 1
     depending on the result of the test.  In contrast to the 'stdpoll'
     function, '_pollmx' does not use cache database and does not fall
     back to polling the IP if the poll fails.  The function can throw
     one of the following exceptions: 'e_failure', 'e_temp_failure'.

 -- Library Function: boolean stdpoll (string EMAIL, string DOMAIN,
          string MAILFROM)

     Performs standard poll for EMAIL, using DOMAIN as 'EHLO' domain and
     MAILFROM as 'MAIL FROM' address.  Returns 0 or 1 depending on the
     result of the test.  Can raise one of the following exceptions:
     'e_failure', 'e_temp_failure'.

     In 'on' statement context, it is synonymous to 'poll' without
     explicit HOST.

 -- Library Function: boolean strictpoll (string HOST, string EMAIL,
          string DOMAIN, string MAILFROM)

     Performs strict poll for EMAIL on host HOST.  See the description
     of 'stdpoll' for the detailed information.

     In 'on' context, it is synonymous to 'poll host HOST'.

   The MAILFROM argument can be a comma-separated list of email
addresses, which can be useful for servers that are unusually picky
about sender addresses.  It is advised, however, that this list always
contain the '<>' address.  For example:

     _pollhost($client_addr, $f, "domain", "postmaster@my.net,<>")

   See also *note mail-from-address: conf-callout.

   Before returning, all described functions set the following built-in
variables:

Variable               Contains
--------------------------------------------------------------------------
last_poll_host         Host name or IP address of the last polled host.
last_poll_sent         Last SMTP command, sent to this host.  If
                       nothing was sent, it contains literal string
                       'nothing'.
last_poll_recv         Last SMTP reply received from this host.  In
                       case of multi-line replies, only the first line
                       is stored.  If nothing was received the variable
                       contains the string 'nothing'.
cache_used             '1' if cached data were used instead of polling,
                       '0' otherwise.  This variable is set by
                       'stdpoll' and 'strictpoll'.  If it equals '1',
                       none of the above variables are modified.
                       *Note cache_used example::, for an example.

Table 5.1: Variables set by polling functions


File: mailfromd.info,  Node: Internet address manipulation functions,  Next: DNS functions,  Prev: Compatibility Callout functions,  Up: Library

5.22 Internet address manipulation functions
============================================

Following functions operate on IPv4 addresses and CIDRs.

 -- Built-in Function: number ntohl (number N)
     Converts the number N, from host to network byte order.  The
     argument N is treated as an unsigned 32-bit number.

 -- Built-in Function: number htonl (number N)
     Converts the number N, from network to host byte order.  The
     argument N is treated as an unsigned 32-bit number.

 -- Built-in Function: number ntohs (number N)
     The argument N is treated as an unsigned 16-bit number.  The
     function converts this number from network to host order.

 -- Built-in Function: number htons (number N)
     The argument N is treated as an unsigned 16-bit number.  The
     function converts this number from host to network order.

 -- Built-in Function: number inet_aton (string S)
     Converts the Internet host address S from the standard
     numbers-and-dots notation into the equivalent integer in host byte
     order.

          inet_aton("127.0.0.1") => 2130706433

     _The numeric data type in MFL is signed, therefore on machines with
     32 bit integers, this conversion can result in a negative number:_

          inet_aton("255.255.255.255") => -1

     _However, this does not affect arithmetical operations on IP
     addresses._

 -- Built-in Function: string inet_ntoa (number N)
     Converts the Internet host address N, given in host byte order to
     string in standard numbers-and-dots notation:

          inet_ntoa(2130706433) => "127.0.0.1"

 -- Built-in Function: number len_to_netmask (number N)
     Convert number of masked bits N to IPv4 netmask:

          inet_ntoa(len_to_netmask(24)) => 255.255.255.0
          inet_ntoa(len_to_netmask(7)) => 254.0.0.0

     If N is greater than 32 the function raises 'e_range' exception.

 -- Built-in Function: number netmask_to_len (number MASK)
     Convert IPv4 netmask MASK into netmask length (number of bits
     preserved by the mask):

          netmask_to_len(inet_aton("255.255.255.0")) => 24
          netmask_to_len(inet_aton("254.0.0.0")) => 7

 -- Library Function: boolean match_cidr (string IP, string CIDR)

     This function is defined in the module 'match_cidr.mf' (*note
     Modules::).

     It returns 'true' if the IP address IP pertains to the IP range
     CIDR.  The first argument, IP, is a string representation of an IP
     address.  The second argument, CIDR, is a string representation of
     a IP range in CIDR notation, i.e.  '"A.B.C.D/N"', where A.B.C.D is
     an IPv4 address and N specifies the "prefix length" - the number of
     shared initial bits, counting from the left side of the address.

     The following example will reject the mail if the IP address of the
     sending machine does not belong to the block '10.10.1.0/19':

          if not match_cidr(${client_addr}, "10.10.1.0/19")
            reject
          fi


File: mailfromd.info,  Node: DNS functions,  Next: Geolocation functions,  Prev: Internet address manipulation functions,  Up: Library

5.23 DNS Functions
==================

MFL offers two sets of functions for querying the Domain Name System.
The 'dns_query' function and associated 'dns_reply_' functions provide a
generalized DNS API.

   Other functions provide a simplified API.

* Menu:

* dns_query::
* Simplified DNS functions::


File: mailfromd.info,  Node: dns_query,  Next: Simplified DNS functions,  Up: DNS functions

5.23.1 dns_query
----------------

 -- Built-in Function: number dns_query (number TYPE, string DOMAIN;
          number SORT, number RESOLVE)
     This function looks up the domain name NAME.  The TYPE argument
     specifies type of the query to perform.  On success, the function
     returns "DNS reply descriptor", a non-negative integer number
     identifying the reply.  It can then be passed to any of the
     'dns_reply_' functions discussed below in order to retrieve the
     information from it.

     If no matching records were found, the function returns '-1'.

     On error, it throws a corresponding exception.

     The TYPE argument is one of the following constants (defined in the
     module 'dns'):

     DNS_TYPE_A
          Query the 'A' record.  The DOMAIN should be the hostname to
          look up.

     DNS_TYPE_NS
          Query the 'NS' records.

     DNS_TYPE_PTR
          Query the 'PTR' record.  The DOMAIN address should be the IP
          address in dotted-quad form.

     DNS_TYPE_MX
          Query the 'MX' records.

     DNS_TYPE_TXT
          Query the 'TXT' records.

     If the query returns multiple RR sets, the optional argument SORT
     controls whether they should be returned in the same order as
     obtained from the DNS (0, the default), or should be sorted (1).

     The optional argument RESOLVE is consulted for TYPE 'DNS_TYPE_MX'
     and 'DNS_TYPE_NS'.  If it is 1, the 'DNS_TYPE_MX' query will return
     host names of the MX servers (by default, it returns IP addresses)
     and the 'DNS_TYPE_NS' query will return IP addresses of the name
     servers (by default it returns hostnames).

     To extract actual data from the 'dns_query' return value, use the
     functions 'dns_reply_count' and 'dns_reply_string'.  The usual
     processing sequence is:

            require dns

            # Send the query and save the reply descriptor
            set n dns_query(DNS_TYPE_NS, domain_name)

            if n >= 0
              # If non-empty set is returned, iterate over each value in it:
              loop for set i 0,
                   while i < dns_reply_count(n),
                   set i i + 1
              do
                # Get the actual data:
                echo dns_reply_string(n, i)
              done
              # Release the memory associated with the reply.
              dns_reply_release(n)
            fi

 -- Built-in Function: void dns_reply_release (number RD)
     Release the memory associated with the reply RD.  If RD is -1, the
     function does nothing.

 -- Built-in Function: number dns_reply_count (number RD)
     Return the number of records in the reply RD.  For convenience, if
     RD is -1, the function returns 0.  If RD is negative (excepting
     -1), a 'e_failure' exception is thrown.

 -- Built-in Function: string dns_reply_string (number RD, number N)
     Returns Nth record from the DNS reply RD.

 -- Built-in Function: number dns_reply_ip (number RD, number N)
     Returns Nth record from the DNS reply RD, if the reply contains IP
     addresses.


File: mailfromd.info,  Node: Simplified DNS functions,  Prev: dns_query,  Up: DNS functions

5.23.2 Simplified DNS functions
-------------------------------

These functions are implemented in two layers: "primitive" built-in
functions which raise exceptions if the lookup fails, and library calls
that are warranted to always return meaningful value without throwing
exceptions.

   The built-in layer is always available.  The library calls become
available after requesting the 'dns' module (*note Modules::):

     require dns

 -- Library Function: string dns_getaddr (string DOMAIN)
     Returns a whitespace-separated list of IP addresses ('A' records)
     for DOMAIN.

 -- Library Function: string dns_getname (string IPSTR)
     Returns a whitespace-separated list of domain names ('PTR' records)
     for the IPv4 address IPSTR.

 -- Library Function: string getmx (string DOMAIN [, boolean IP])
     Returns a whitespace-separated list of 'MX' names (if IP is not
     given or if it is '0') or 'MX' IP addresses (if 'IP!=0')) for
     DOMAIN.  Within the returned string, items are sorted in order of
     increasing 'MX' priority.  If DOMAIN has no 'MX' records, an empty
     string is returned.  If the DNS query fails, 'getmx' raises an
     appropriate exception.

     Examples:

          getmx("mafra.cz") => "smtp1.mafra.cz smtp2.mafra.cz relay.iol.cz"
          getmx("idnes.cz") => "smtp1.mafra.cz smtp2.mafra.cz relay.iol.cz"
          getmx("gnu.org")  => "mx10.gnu.org mx20.gnu.org"
          getmx("org.pl") => ""

     _Notes_:

       1. Number of items returned by 'getmx(DOMAIN)' can differ from
          that obtained from 'getmx(DOMAIN, 1)', e.g.:

               getmx("aol.com")
                 => mailin-01.mx.aol.com mailin-02.mx.aol.com
                           mailin-03.mx.aol.com mailin-04.mx.aol.com
               getmx("aol.com", 1)
                 => 64.12.137.89 64.12.137.168 64.12.137.184
                           64.12.137.249 64.12.138.57 64.12.138.88
                           64.12.138.120 64.12.138.185 205.188.155.89
                           205.188.156.185 205.188.156.249 205.188.157.25
                           205.188.157.217 205.188.158.121 205.188.159.57
                           205.188.159.217

       2. This function is a wrapper over 'dns_query'.

          If you intend to iterate over returned values, better use
          'dns_query' directly, e.g.  instead of doing

               string_list_iterate(getmx(domain), ` ', MX, `do_something(MX)')

          use

                 set n dns_query(DNS_TYPE_MX, domain)
                 if n >= 0
                   loop for set i 0,
                        while i < dns_reply_count(n),
                        set i i + 1
                   do
                     do_something(dns_reply_string(n, i))
                   done
                   dns_reply_release(n)
                 fi

          *Note dns_query::, for details about the 'dns_query' function
          and associated 'dns_reply_*' calls.

       3. This interface is semi-deprecated.

          It will most probably be removed in future releases, when
          array data types are implemented.

 -- Built-in Function: boolean primitive_hasmx (string DOMAIN)
     Returns 'true' if the domain name given by its argument has any
     'MX' records.

     If the DNS query fails, this function throws 'failure' or
     'temp_failure'.

 -- Library Function: boolean hasmx (string DOMAIN)
     Returns 'true' if the domain name given by its argument has any
     'MX' records.

     Otherwise, if DOMAIN has no 'MX's or if the DNS query fails,
     'hasmx' returns 'false'.

 -- Built-in Function: string primitive_hostname (string IP)
     The IP argument should be a string representing an IP address in
     "dotted-quad" notation.  The function returns the canonical name of
     the host with this IP address obtained from DNS lookup.  For
     example

          primitive_hostname (${client_addr})

     returns the fully qualified domain name of the host represented by
     Sendmail variable 'client_addr'.

     If there is no 'PTR' record for IP, 'primitive_hostname' raises the
     exception 'e_not_found'.

     If DNS query fails, the function raises 'failure' or
     'temp_failure', depending on the character of the failure.

 -- Library Function: string hostname (string IP)
     The IP argument should be a string representing an IP address in
     "dotted-quad" notation.  The function returns the canonical name of
     the host with this IP address obtained from DNS lookup.

     If there is no 'PTR' record for IP, or if the lookup fails, the
     function returns IP unchanged.

     The previous 'mailfromd' versions used the following paradigm to
     check if an IP address resolves:

            if hostname(ip) != ip
              ...

 -- Built-in Function: boolean primitive_ismx (string DOMAIN, string
          HOST)
     The DOMAIN argument is any valid domain name, the HOST is a host
     name or IP address.

     The function returns 'true' if HOST is one of the 'MX' records for
     the DOMAIN.

     If DOMAIN has no 'MX' records, 'primitive_ismx' raises exception
     'e_not_found'.

     If DNS query fails, the function raises 'failure' or
     'temp_failure', depending on the character of the failure.

 -- Library Function: boolean ismx (string DOMAIN, string HOST)
     The DOMAIN argument is any valid domain name, the HOST is a host
     name or IP address.

     The function returns 'true' if HOST is one of the 'MX' records for
     the DOMAIN.  Otherwise it returns 'false'.

     If DOMAIN has no 'MX' records, or if the DNS query fails, the
     function returns 'false'.

 -- Built-in Function: string primitive_resolve (string HOST, [string
          DOMAIN])
     Reverse of 'primitive_hostname'.  The 'primitive_resolve' function
     returns the IP address for the host name specified by HOST
     argument.  If HOST has no A records, the function raises the
     exception 'e_not_found'.

     If DNS lookup fails, the function raises 'failure' or
     'temp_failure', depending on the character of the failure.

     If the optional DOMAIN argument is given, it will be appended to
     HOST (with an intermediate dot), before querying the DNS.  For
     example, the following two expressions will return the same value:

          primitive_resolve("puszcza.gnu.org.ua")
          primitive_resolve("puszcza", "gnu.org.ua")

     There is a considerable internal difference between one-argument
     and two-argument forms of 'primitive_resolve': the former queries
     DNS for an 'A' record, whereas the latter queries it for any record
     matching HOST in the domain DOMAIN and then selects the most
     appropriate one.  For example, the following two calls are
     equivalent:

          primitive_hostname("213.130.0.22")
          primitive_resolve("22.0.130.213", "in-addr.arpa")

     This makes it possible to use 'primitive_resolve' for querying DNS
     black listing domains.  *Note match_dnsbl::, for a working example
     of this approach.  See also *note match_rhsbl::, for another
     practical example of the use of the two-argument form.

 -- Library Function: string resolve (string HOST, [string DOMAIN])
     Reverse of 'hostname'.  The 'resolve' function returns IP address
     for the host name specified by HOST argument.  If the host name
     cannot be resolved, or a DNS failure occurs, the function returns
     '"0"'.

     This function is entirely equivalent to 'primitive_resolve' (see
     above), except that it never raises exceptions.

 -- Built-in Function: string ptr_validate (string IP)
     Tests whether the DNS reverse-mapping for IP exists and correctly
     points to a domain name within a particular domain.

     First, it obtains all PTR records for IP.  Then, for each record
     returned, a look up for A records is performed and IP addresses of
     each record are compared against IP.  The function returns true if
     a matching A record is found.

 -- Built-in Function: boolean primitive_hasns (string DOMAIN)
     Returns 'True' if the domain DOMAIN has at least one 'NS' record.
     Throws exception if DNS lookup fails.

 -- Library Function: boolean hasns (string DOMAIN)
     Returns 'True' if the domain DOMAIN has at least one 'NS' record.
     Returns 'False' if there are no 'NS' records or if the DNS lookup
     fails.

 -- Library Function: string getns (string DOMAIN ; boolean RESOLVE,
          boolean SORT)
     Returns a whitespace-separated list of all the 'NS' records for the
     domain DOMAIN.  Optional parameters RESOLVE and SORT control the
     formatting.  If RESOLVE is 0 (the default), the resulting string
     will contain IP addresses of the NS servers.  If RESOLVE is not 0,
     hostnames will be returned instead.  If SORT is 1, the returned
     items will be sorted.

     If the DNS query fails, 'getns' raises an appropriate exception.

     _Notes_:
       1. This function is a wrapper over 'dns_query'.

          If you intend to iterate over returned values, better use
          'dns_query' directly, e.g.  instead of doing

               string_list_iterate(getns(domain), ` ', NS, `do_something(NS)')

          use

                 set n dns_query(DNS_TYPE_NS, domain)
                 if n >= 0
                   loop for set i 0,
                        while i < dns_reply_count(n),
                        set i i + 1
                   do
                     do_something(dns_reply_string(n, i))
                   done
                   dns_reply_release(n)
                 fi

          *Note dns_query::, for details about the 'dns_query' function
          and associated 'dns_reply_*' calls.

       2. This interface is semi-deprecated.

          It will most probably be removed in future releases, when
          array data types are implemented.


File: mailfromd.info,  Node: Geolocation functions,  Next: Database functions,  Prev: DNS functions,  Up: Library

5.24 Geolocation functions
==========================

The "geolocation functions" allow you to identify the country where the
given IP address or host name is located.  These functions are available
only if the 'libmaxminddb' library is installed and 'mailfromd' is
compiled with the 'GeoIP2' support.

   The 'libmaxminddb' library is distributed by 'MaxMind' under the
terms of the 'Apache License' Version 2.0.  It is available from
<https://dev.maxmind.com/geoip/geoip2/downloadable/#MaxMind_APIs>.

   Historically, 'mailfromd' supports also the legacy 'GeoIP' library.
If you are interested in it, please refer to *note Legacy geoip
support::.

 -- Built-in Function: void geoip2_open (string FILENAME)
     Opens the geolocation database file FILENAME.  The database must be
     in GeoIP2 format.

     If the database cannot be opened, 'geoip2_open' throws the
     'e_failure' exception.

     If this function is not called, geolocation functions described
     below will try to open the database file
     '/usr/share/GeoIP/GeoLite2-City.mmdb'.

 -- Built-in Function: string geoip2_dbname (void)
     Returns the name of the geolocation database currently in use.

   The geolocation database for each IP address, which serves as a look
up key, stores a set of items describing this IP. This set is organized
as a map of key-value pairs.  Each key is a string value.  A value can
be a scalar, another map or array of values.  Using JSON notation, the
result of a look up in the database might look as:

     {
         "country":{
             "geoname_id":2921044,
             "iso_code":"DE",
             "names":{
                 "en": "Germany",
                 "de": "Deutschland",
                 "fr":"Allemagne"
             },
         },
         "continent":{
             "code":"EU",
             "geoname_id":6255148,
             "names":{
                 "en":"Europe",
                 "de":"Europa",
                 "fr":"Europe"
             }
         },
         "location":{
             "accuracy_radius":200,
             "latitude":49.4478,
             "longitude":11.0683,
             "time_zone":"Europe/Berlin"
         },
         "city":{
             "geoname_id":2861650,
             "names":{
                 "en":"Nuremberg",
                 "de":"Nürnberg",
                 "fr":"Nuremberg"
             }
         },
         "subdivisions":[{
             "geoname_id":2951839,
             "iso_code":"BY",
             "names":{
                 "en":"Bavaria",
                 "de":"Bayern",
                 "fr":"Bavière"
             }
         }
     }

   Each particular data item in such structure is identified by its
"search path", which is a dot-delimited list of key names leading to
that value.  For example, using the above map, the name of the city in
English can be retrieved using the key 'city.names.en'.

 -- Built-in Function: string geoip2_get (string IP, string PATH)
     Looks up the IP address IP in the geolocation database.  If found,
     returns data item identified by the search path PATH.

     The function can throw the following exceptions:

     e_not_found
          The IP was not found in the database.

     e_range
          The PATH does not exist the returned map.

     e_failure
          General error occurred.  E.g.  the database cannot be opened,
          IP is not a valid IP address, etc.

 -- Built-in Function: string geoip2_get_json (string IP [; number
          INDENT)
     Looks up the IP in the database and returns entire data set
     associated with it, formatted as a JSON object.  If the optional
     parameter INDENT is supplied and is greater than zero, it gives the
     indentation for each nesting level in the JSON object.

   Applications may test whether the GeoIP2 support is present and
enable the corresponding code blocks conditionally, by testing if the
'WITH_GEOIP2' m4 macro is defined.  For example, the following code adds
to the message the 'X-Originator-Country' header, containing the 2
letter code of the country where the client machine is located.  If
'mailfromd' is compiled without 'GeoIP' support, it does nothing:

     m4_ifdef(`WITH_GEOIP2',`
       try
       do
         header_add("X-Originator-Country", geoip2_get($client_addr,
                                                       'country.iso_code'))
       done
       catch e_not_found or e_range
       do
         pass
       done
     ')

* Menu:

* Legacy geoip support::


File: mailfromd.info,  Node: Legacy geoip support,  Up: Geolocation functions

5.24.1 Legacy geoip support
---------------------------

For compatibility with older releases, 'mailfromd' supports the legacy
'GeoIP' library.  This support is going to be removed in the next
release, so its use is not recommended.  Please use 'GeoIP2' instead.

   The support for the legacy 'GeoIP' library is available if
'mailfromd' is compiled with the 'GeoIP' support (the '--with-geoip'
configure option).  The 'm4' macro 'WITH_GEOIP' is defined if it is so.

   The legacy 'GeoIP' is distributed by 'MaxMind' under the terms of the
GNU Lesser General Public License.  The library is available from
<http://www.maxmind.com/app/c>.

 -- Built-in Function: string geoip_country_code_by_addr ( string IP [,
          bool TLC])
     Look up the 'ISO 3166-1' country code corresponding to the IP
     address IP.  If TLC is given and is not zero, return the 3 letter
     code, otherwise return the 2 letter code.

 -- Built-in Function: string geoip_country_code_by_name ( string NAME
          [, bool TLC])
     Look up the 'ISO 3166-1' country code corresponding to the host
     name NAME.  If TLC is given and is not zero, return the 3 letter
     code, otherwise return the 2 letter code.

   If it is impossible to locate the country, both functions raise the
'e_not_found' exception.  If an error internal to the 'GeoIP' library
occurs, they raise the 'e_failure' exception.

   Applications may test whether the GeoIP support is present and enable
corresponding code blocks conditionally, by testing if the 'WITH_GEOIP'
m4 macro is defined.  For example, the following code adds to the
message the 'X-Originator-Country' header, containing the 2 letter code
of the country where the client machine is located.  If 'mailfromd' is
compiled without 'GeoIP' support, it does nothing:

     m4_ifdef(`WITH_GEOIP',`
       header_add("X-Originator-Country", geoip_country_code_by_addr($client_addr))
     ')


File: mailfromd.info,  Node: Database functions,  Next: System functions,  Prev: Geolocation functions,  Up: Library

5.25 Database Functions
=======================

The functions described below provide a user interface to DBM databases.

   Each DBM database is a separate disk file that keeps "key/value
pairs".  The interface allows to retrieve the value corresponding to a
given key.  Both 'key' and 'value' are null-terminated character
strings.  To lookup a key, it is important to know whether its length
includes the terminating null byte.  By default, it is assumed that it
does not.

   Another important database property is the "file mode" of the
database file.  The default file mode is '640' (i.e. 'rw-r----', in
symbolic notation).

   Both properties can be configured using the 'dbprop' pragma:

     #pragma dbprop PATTERN PROP [PROP]

   The PATTERN is the database name or shell-style globbing pattern.
Properties defined by that pragma apply to each database whose name
matches this pattern.  If several 'dbprop' pragmas match the database
name, the one that matches exactly is preferred.

   The rest of arguments define properties for that database.  The valid
values for PROP are:

  1. The word 'null', meaning that the terminating null byte is included
     in the key length.

     Setting 'null' property is necessary, for databases created with
     'makemap -N hash' command.

  2. File mode for the disk file.  It can be either an octal number, or
     a symbolic mode specification in ls-like format.  E.g., the
     following two formats are equivalent:

          640
          rw-r----

   For example, consider the following pragmas:

     #pragma dbprop /etc/mail/whitelist.db 640

   It tells that the database file 'whitelist.db' has privileges '640'
and do not include null in the key length.

   Similarly, the following pragma:

     #pragma dbprop `/etc/mail/*.db' null 600

declares that all database files in directory '/etc/mail' have
privileges '640' and include null terminator in the key length.
_Notice_, the use of 'm4' quoting characters in the example below.
Without them, the sequence '/*' would have been taken as the beginning
of a comment.

   Additionally, for compatibility with previous versions (up to 5.0),
the terminating null property can be requested via an optional argument
to the database functions (in description below, marked as NULL).

 -- Built-in Function: boolean dbmap (string DB, string KEY, [boolean
          NULL])
     Looks up KEY in the DBM file DB and returns 'true' if it is found.

     See above for the meaning of NULL.

     *Note whitelisting::, for an example of using this function.

 -- Built-in Function: string dbget (string DB, string KEY [, string
          DEFAULT, boolean NULL])
     Looks up KEY in the database DB and returns the value associated
     with it.  If the key is not found returns DEFAULT, if specified, or
     empty string otherwise.

     See above for the meaning of NULL.

 -- Built-in Function: void dbput (string DB, string KEY, string VALUE
          [, boolean NULL, number MODE ])
     Inserts in the database a record with the given KEY and VALUE.  If
     a record with the given KEY already exists, its value is replaced
     with the supplied one.

     See above for the meaning of NULL.  Optional MODE allows to
     explicitly specify the file mode for this database.  See also
     '#pragma dbprop', described above.

 -- Built-in Function: void dbinsert (string DB, string KEY, string
          VALUE [, boolean REPLACE, boolean NULL, number MODE ])
     This is an improved variant of 'dbput', which provides a better
     control on the actions to take if the KEY already exists in the
     database.  Namely, if REPLACE is 'True', the old value is replaced
     with the new one.  Otherwise, the 'e_exists' exception is thrown.

 -- Built-in Function: void dbdel (string DB, string KEY [, boolean
          NULL, number MODE])
     Delete from the database the record with the given KEY.  If there
     are no such record, return without signalling error.

     If the optional NULL argument is given and is not zero, the
     terminating null character will be included in KEY length.

     Optional MODE allows to explicitly specify the file mode for this
     database.  See also '#pragma dbprop', described above.

   The functions above have also the corresponding exception-safe
interfaces, which return cleanly if the 'e_dbfailure' exception occurs.
To use these interfaces, request the 'safedb' module:

     require safedb

   The exception-safe interfaces are:

 -- Library Function: string safedbmap (string DB, string KEY [, string
          DEFAULT, boolean NULL])

     This is an exception-safe interface to 'dbmap'.  If a database
     error occurs while attempting to retrieve the record, 'safedbmap'
     returns DEFAULT or '0', if it is not defined.

 -- Library Function: string safedbget (string DB, string KEY [, string
          DEFAULT, boolean NULL])

     This is an exception-safe interface to 'dbget'.  If a database
     error occurs while attempting to retrieve the record, 'safedbget'
     returns DEFAULT or empty string, if it is not defined.

 -- Library Function: void safedbput (string DB, string KEY, string
          VALUE [, boolean NULL])

     This is an exception-safe interface to 'dbput'.  If a database
     error occurs while attempting to retrieve the record, the function
     returns without raising exception.

 -- Library Function: void safedbdel (string DB, string KEY [, boolean
          NULL])

     This is an exception-safe interface to 'dbdel'.  If a database
     error occurs while attempting to delete the record, the function
     returns without raising exception.

   The verbosity of 'safedb' interfaces in case of database error is
controlled by the value of 'safedb_verbose' variable.  If it is '0',
these functions return silently.  This is the default behavior.
Otherwise, if 'safedb_verbose' is not '0', these functions log the
detailed diagnostics about the database error and return.

   The following functions provide a sequential access to the contents
of a DBM database:

 -- Built-in Function: number dbfirst (string NAME)
     Start sequential access to the database NAME.  The return value is
     an opaque identifier, which is used by the remaining sequential
     access functions.  This number is '0' if the database is empty.

 -- Built-in Function: number dbnext (number DN)
     Select next record form the database.  The argument DN is the
     access identifier, returned by a previous call to 'dbfirst' or
     'dbnext'.

     Returns new access identifier.  This number is '0' if all records
     in the database have been visited.

   The usual approach for iterating over all records in a database
DBNAME is:

       loop for number dbn dbfirst(DBNAME)
       do
         ...
       done while dbnext(dbn)

   The following two functions can be used to access values of the
currently selected database record.  Their argument, DN, is the access
identifier, returned by a previous call to 'dbfirst' or 'dbnext'.

 -- Built-in Function: string dbkey (number DN)
     Return the key from the selected database record.

 -- Built-in Function: string dbvalue (number DN)
     Return the value from the selected database record.

 -- Built-in Function: number db_expire_interval (string FMT)
     The FMT argument is a database format identifier (*note Database
     Formats::).  If it is valid, the function returns the expiration
     interval for that format.  Otherwise, 'db_expire_interval' raises
     the 'e_not_found' exception.

 -- Built-in Function: string db_name (string FMTID)
     The FMTID argument is a database format identifier (*note Database
     Formats::).  The function returns the file name for that format.
     If FMTID does not match any known format, 'db_name' raises the
     'e_not_found' exception.

 -- Built-in Function: number db_get_active (string FMTID)
     Returns the flag indicating whether the cache database FMTID is
     currently enabled.  If FMTID does not match any known format,
     'db_name' raises the 'e_not_found' exception.

 -- Built-in Function: void db_set_active (string FMTID, boolean ENABLE)
     Enables the cache database FMTID if ENABLE is 'True', or disables
     it otherwise.  For example, to disable DNS caching, do:

          db_set_active("dns", 0)

 -- Built-in Function: boolean relayed (string DOMAIN)
     Returns 'true' if the string DOMAIN is found in one of relayed
     domain files (*note relayed-domain-file: conf-base.).  The usual
     construct is:

          if relayed(hostname(${client_addr}))
            ...

     which yields 'true' if the IP address from 'Sendmail' variable
     'client_addr' is relayed by the local machine.


File: mailfromd.info,  Node: System functions,  Next: Passwd functions,  Prev: Database functions,  Up: Library

5.26 System functions
=====================

 -- Built-in Function: boolean access (string PATHNAME, number MODE)
     Checks whether the calling process can access the file PATHNAME.
     If PATHNAME is a symbolic link, it is dereferenced.  The function
     returns 'True' if the file can be accessed and 'False'
     otherwise(1).

     Symbolic values for MODE are provided in module 'status':

     F_OK
          Tests for the existence of the file.

     R_OK
          Tests whether the file exists and grants read permission.

     W_OK
          Tests whether the file exists and grants write permission.

     X_OK
          Tests whether the file exists and grants execute permission.

 -- Built-in Function: string getenv (string NAME)
     Searches the environment list for the variable NAME and returns its
     value.  If the variable is not defined, the function raises the
     exception 'e_not_found'.

 -- Built-in Function: string gethostname ([bool FQN])
     Return the host name of this machine.

     If the optional FQN is given and is 'true', the function will
     attempt to return fully-qualified host name, by attempting to
     resolve it using DNS.

 -- Built-in Function: string getdomainname ()
     Return the domain name of this machine.  Note, that it does not
     necessarily coincide with the actual machine name in DNS.

     Depending on the underlying 'libc' implementation, this call may
     return empty string or the string '(none)'.  Do not rely on it to
     get the real domain name of the box 'mailfromd' runs on, use
     'localdomain' (see below) instead.

 -- Library Function: string localdomain ()
     Return the local domain name of this machine.

     This function first uses 'getdomainname' to make a first guess.  If
     it does not return a meaningful value, 'localdomain' calls
     'gethostname(1)' to determine the fully qualified host name of the
     machine, and returns its domain part.

     To use this function, require the 'localdomain' module (*note
     Modules::), e.g.: 'require localdomain'.

 -- Built-in Function: number time ()
     Return the time since the Epoch (00:00:00 UTC, January 1, 1970),
     measured in seconds.

 -- Built-in Function: string strftime (string FMT, number TIMESTAMP)
 -- Built-in Function: string strftime (string FMT, number TIMESTAMP,
          boolean GMT)
     Formats the time TIMESTAMP (seconds since the Epoch) according to
     the format specification FORMAT.  Ordinary characters placed in the
     format string are copied to the output without conversion.
     Conversion specifiers are introduced by a '%' character.  *Note
     Time and Date Formats::, for a detailed description of the
     conversion specifiers.  We recommend using single quotes around FMT
     to prevent '%' specifiers from being interpreted as 'Mailfromd'
     variables (*Note Literals::, for a discussion of quoted literals
     and variable interpretation within them).

     The TIMESTAMP argument can be a return value of 'time' function
     (see above).

     For example:
          strftime('%Y-%m-%d %H:%M:%S %Z', 1164477564)
           => 2006-11-25 19:59:24 EET
          strftime('%Y-%m-%d %H:%M:%S %Z', 1164477564, 1)
           => 2006-11-25 17:59:24 GMT

 -- Built-in Function: string uname (string FORMAT)
     This function returns system information formatted according to the
     format specification FORMAT.  Ordinary characters placed in the
     format string are copied to the output without conversion.
     Conversion specifiers are introduced by a '%' character.  The
     following conversions are defined:

     %s
          Name of this system.

     %n
          Name of this node within the communications network to which
          this node is attached.  Note, that it does not necessarily
          coincide with the actual machine name in DNS.

     %r
          Kernel release.

     %v
          Kernel version.

     %m
          Name of the hardware type on which the system is running.

     For example:

            uname('%n runs %s, release %r on %m')
              => "Trurl runs Linux, release 2.6.26 on i686"

     Notice the use of single quotes.

 -- Built-in Function: void unlink (string NAME)
     Unlinks (deletes) the file NAME.  On error, throws the 'e_failure'
     exception.

 -- Built-in Function: number system (string STR)
     The function 'system' executes a command specified in STR by
     calling '/bin/sh -c string', and returns -1 on error or the return
     status of the command otherwise.

 -- Built-in Function: void sleep (number SECS[, USEC])
     Sleep for SECS seconds.  If optional USEC argument is given, it
     specifies additional number of microseconds to wait for.  For
     example, to suspend execution of the filter for 1.5 seconds:

            sleep(1,500000)

     This function is intended mostly for debugging and experimental
     purposes.

 -- Built-in Function: number umask (number MASK)
     Set the umask to MASK & 0777.  Return the previous value of the
     mask.

   ---------- Footnotes ----------

   (1) _Note_, that the return code is inverted in respect to the system
function 'access(2)'.


File: mailfromd.info,  Node: Passwd functions,  Next: Sieve Interface,  Prev: System functions,  Up: Library

5.27 System User Database
=========================

 -- Built-in Function: string getpwnam (string NAME)
 -- Built-in Function: string getpwuid (number UID)
     Look for the user NAME ('getpwnam') or user ID UID ('getpwuid') in
     the system password database and return the corresponding record,
     if found.  If not found, raise the 'e_not_found' exception.

     The returned record consists of six fields, separated by colon
     sign:

          uname:passwd:uid:gid:gecos:dir:shell

     Field                  Meaning
     -------------------------------------------------------------------
     uname                  user name
     passwd                 user password
     uid                    user ID
     gid                    group ID
     gecos                  real name
     dir                    home directory
     shell                  shell program

     For example:

          getpwnam("gray")
          => "gray:x:1000:1000:Sergey Poznyakoff:/home/gray:/bin/bash"

   Following two functions can be used to test for existence of a key in
the user database:

 -- Built-in Function: boolean mappwnam (string NAME)
 -- Built-in Function: boolean mappwuid (number UID)
     Return 'true' if NAME (or UID) is found in the system user
     database.


File: mailfromd.info,  Node: Sieve Interface,  Next: Interfaces to Third-Party Programs,  Prev: Passwd functions,  Up: Library

5.28 Sieve Interface
====================

'Sieve' is a powerful mail filtering language, defined in RFC 3028.
'Mailfromd' supports an extended form of this language.  For a
description of the language and available extensions, see *note Sieve
Language: (mailutils)Sieve Language.

 -- Built-in Function: boolean sieve (number MSG, string SCRIPT [,
          number FLAGS, string FILE, number LINE])
     Compile the Sieve program SCRIPT and execute it over the message
     identified by the descriptor NMSG.

     Optional FLAGS modify the behavior of the function.  It is a
     bit-mask field, consisting of a bitwise 'or' of one or more of the
     following flags, defined in 'sieve.mf':

     'MF_SIEVE_FILE'
          The SCRIPT argument specifies the name of a Sieve program
          file.  This is the default.

     'MF_SIEVE_TEXT'
          The SCRIPT argument is a string containing entire Sieve
          program.  Optional arguments FILE and LINE can be used to fix
          source locations in Sieve diagnostic messages (see below).

     'MF_SIEVE_LOG'
          Log every executed 'Sieve' action.

     'MF_SIEVE_DEBUG_TRACE'
          Trace execution of 'Sieve' tests.

     'MF_SIEVE_DEBUG_INSTR'
          Log every instruction, executed in the compiled 'Sieve' code.
          This produces huge amounts of output and is rarely useful,
          unless you suspect some bug in 'Sieve' implementation and wish
          to trace it.

     For example, 'MF_SIEVE_LOG|MF_SIEVE_DEBUG_TRACE' enables logging
     'Sieve' actions and tests.

     The 'sieve' function returns 'true' if the message was accepted by
     the SCRIPT program, and 'false' otherwise.  Here, the word
     "accepted" means that some form of 'KEEP' action (*note keep:
     (mailutils)Actions.) was executed over the message.

     While executing the Sieve script, Sieve environment ('RFC 5183') is
     initialized as follows:

     domain
          The domain name of the server Sieve is running on.
     host
          Host name of the server Sieve is running on.
     location
          The string 'MTA'.
     name
          The string 'GNU Mailutils'.
     phase
          The string 'pre'.
     remote-host
          Defined to the value of 'client_ptr' macro, if it was
          required.
     remote-ip
          Defined to the value of 'client_addr' macro, if it was
          required.
     version
          The version of GNU Mailutils.

   The following example discards each message not accepted by the
'Sieve' program '/etc/mail/filter.siv':

     require 'sieve'

     group eom
     do
       if not sieve(current_message(), "/etc/mail/filter.siv", MF_SIEVE_LOG)
          discard
       fi
     done

   The Sieve program can be embedded in the MFL filter, as shown in the
example below:

     require 'sieve'

     prog eom
     do
       if not sieve(current_message(),
                    "require \"fileinto\";\n"
                    "fileinto \"/tmp/sieved.mbox\";",
                    MF_SIEVE_TEXT | MF_SIEVE_LOG)
          discard
       fi
     done

   In such cases, any Sieve diagnostics (error messages, traces, etc.)
will be marked with the locations relative to the line where the call to
'sieve' appears.  For example, the above program produces the following
in the log:

     prog.mf:7: FILEINTO; delivering into /tmp/sieved.mbox

   Notice, that the line number correctly refers to the line where the
'fileinto' action appears in the source.  However, there are cases where
the reported line number is incorrect.  This happens, for instance, if
SCRIPT is a string variable defined elsewhere.  To handle such cases,
'sieve' accepts two optional parameters which are used to compute the
location in the Sieve program.  The FILE parameter specifies the file
name where the definition of the program appears, and the LINE parameter
gives the number of line in that file where the program begins.  For
example:

     require 'sieve'

     const sieve_prog_line __line__ + 2
     string sieve_prog <<EOT
     require "fileinto";
     fileinto "/tmp/sieved.mbox";
     EOT

     prog eom
     do
       if not sieve(current_message(),
                    sieve_prog, MF_SIEVE_TEXT | MF_SIEVE_LOG,
                    __file__, sieve_prog_line)
          discard
       fi
     done

   The actual Sieve program begins two lines below the 'sieve_prog_line'
constant definition, which is reflected in its initialization.


File: mailfromd.info,  Node: Interfaces to Third-Party Programs,  Next: Rate limiting functions,  Prev: Sieve Interface,  Up: Library

5.29 Interfaces to Third-Party Programs
=======================================

A set of functions is defined for interfacing with other filters via
TCP.  Currently implemented are interfaces with 'SpamAssassin' 'spamd'
daemon and with 'ClamAV' anti-virus.

   Both interfaces work much the same way: the remote filter is
connected and the message is passed to it.  If the remote filter
confirms that the message matches its requirements, the function returns
'true'.  Notice that in practice that means that such a message _should
be rejected or deferred_.

   The address of the remote filter is supplied as the second argument
in the form of a standard URL:

     PROTO://PATH[:PORT]

The PROTO part specifies the "connection protocol".  It should be 'tcp'
for the TCP connection and 'file' or 'socket' for the connection via
UNIX socket.  In the latter case the PROTO part can be omitted.  When
using TCP connection, the PATH part gives the remote host name or IP
address and the optional PORT specifies the port number or service name
to use.  For example:

     # connect to 'remote.filter.net' on port 3314:
     tcp://remote.filter.net:3314

     # the same, using symbolic service name (must be defined in
     # '/etc/services'):
     tcp://remote.filter.net:spamd

     # Connect via a local UNIX socket (equivalent forms):
     /var/run/filter.sock
     file:///var/run/filter.sock
     socket:///var/run/filter.sock

   The description of the interface functions follows.

* Menu:

* SpamAssassin::
* DSPAM::
* ClamAV::


File: mailfromd.info,  Node: SpamAssassin,  Next: DSPAM,  Up: Interfaces to Third-Party Programs

5.29.1 SpamAssassin
-------------------

 -- Built-in Function: boolean spamc (number MSG, string URL, number
          PREC, number COMMAND)
     Send the message MSGt to the SpamAssassin daemon ('spamd')
     listening on the given URL.  The COMMAND argument identifies what
     kind of processing is needed for the message.  Allowed values are:

     SA_SYMBOLS
          Process the message and return 1 or 0 depending on whether it
          is diagnosed as spam or not.  Store SpamAssassin keywords in
          the global variable 'sa_keywords' (see below).

     SA_REPORT
          Process the message and return 1 or 0 depending on whether it
          is diagnosed as spam or not.  Store entire SpamAssassin report
          in the global variable 'sa_keywords'.

     SA_LEARN_SPAM
          Learn the supplied message as spam.

     SA_LEARN_HAM
          Learn the supplied message as ham.

     SA_FORGET
          Forget any prior classification of the message.

     The second argument, PREC, gives the precision, in decimal digits,
     to be used when converting SpamAssassin diagnostic data and storing
     them into 'mailfromd' variables.

     The floating point SpamAssassin data are converted to the integer
     'mailfromd' variables using the following relation:

          VAR = int(SA-VAR * 10**PREC)

     where SA-VAR stands for the SpamAssassin value and VAR stands for
     the corresponding 'mailfromd' one.  'int()' means taking the
     integer part and '**' denotes the exponentiation operator.

     The function returns additional information via the following
     variables:

     'sa_score'
          The spam score, converted to integer as described above.  To
          convert it to a floating-point representation, use
          'sa_format_score' function (*note sa_format_score: String
          manipulation.).  See also the example below.

     'sa_threshold'
          The threshold, converted to integer form.

     'sa_keywords'
          If COMMAND is 'SA_SYMBOLS', this variable contains a string of
          comma-separated SpamAssassin keywords identifying this
          message, e.g.:

               ADVANCE_FEE_1,AWL,BAYES_99

          If COMMAND is 'SA_REPORT', the value of this variable is a
          "spam report" message.  It is a multi-line textual message,
          containing detailed description of spam scores in a tabular
          form.  It consists of the following parts:

            1. A preamble.
            2. Content preview.

               The words 'Content preview', followed by a colon and an
               excerpt of the message body.

            3. Content analysis details.

               It has the following form:

                    Content analysis details: (SCORE points, MAX required)

               where SCORE and MAX are spam score and threshold in
               floating point.

            4. Score table.

               The score table is formatted in three columns:

               pts
                    The score, as a floating point number with one
                    decimal digit.

               rule name
                    SpamAssassin rule name that contributed this score.

               description
                    Textual description of the rule

               The score table can be extracted from 'sa_keywords' using
               'sa_format_report_header' function (*note
               sa_format_report_header: String manipulation.), as
               illustrated in the example below.

          The value of this variable is undefined if COMMAND is
          'SA_LEARN_SPAM', 'SA_LEARN_HAM' or 'SA_FORGET'.

     The 'spamc' function can signal the following exceptions:
     'e_failure' if the connection fails, 'e_url' if the supplied URL is
     invalid and 'e_range' if the supplied port number is out of the
     range 1-65535.

     An example of using this function:

          prog eom
          do
            if spamc(current_message(), "tcp://192.168.10.1:3333", 3,
                     SA_SYMBOLS)
              reject 550 5.7.0
                   "Spam detected, score %sa_score with threshold %sa_threshold"
            fi
          done

     Here is a more advanced example:

          prog eom
          do
            set prec 3
            if spamc(current_message(),
                     "tcp://192.168.10.1:3333", prec, SA_REPORT)
              add "X-Spamd-Status" "SPAM"
            else
              add "X-Spamd-Status" "OK"
            fi
            add "X-Spamd-Score" sa_format_score(sa_score, prec)
            add "X-Spamd-Threshold" sa_format_score(sa_threshold, prec)
            add "X-Spamd-Keywords" sa_format_report_header(sa_keywords)
          done

 -- Library Function: boolean sa (string URL, number PREC; number
          COMMAND)
     Additional interface to the 'spamc' function, provided for backward
     compatibility.  It is equivalent to

          spamc(current_message(), URL, PREC, COMMAND)

     If COMMAND is not supplied, 'SA_SYMBOLS' is used.


File: mailfromd.info,  Node: DSPAM,  Next: ClamAV,  Prev: SpamAssassin,  Up: Interfaces to Third-Party Programs

5.29.2 DSPAM
------------

DSPAM is a statistical spam filter distributed under the terms of the
GNU General Public License.  It is available from
<http://dspam.sourceforge.net>.

   MFL provides an interface to DSPAM functionality if the 'libdspam'
library is installed and 'mailfromd' is linked with it.  The 'm4' macro
'WITH_DSPAM' is defined if it is so.

   The DSPAM functions and definitions become available after requiring
the 'dspam' module:

     require 'dspam'

 -- Built-in Function: number dspam (number MSG, number MODE_FLAGS;
          number CLASS_SOURCE)
     Analyze a message using DSPAM. The message is identified by its
     descriptor, passed in the MSG argument.

     The MODE_FLAGS argument controls the function behavior.  Its value
     is a bitwise OR of operation mode, flag, tokenizer and training
     mode.  "Operation mode" defines what 'dspam' is supposed to do with
     the message.  Its value is either 'DSM_PROCESS' if full processing
     of the message is intended (the default), or 'DSM_CLASSIFY', if the
     message must only be classified.

     Optional "flag" bits turn on additional functionality.  The
     'DSF_SIGNATURE' bit instructs 'dspam' to create a signature for the
     message - a unique string which can subsequently be used to
     identify that particular message.  Upon return from the function,
     the signature is stored in the 'dspam_signature' variable.

     The 'DSF_NOISE' bit enables Bayesian noise reduction, and
     'DSF_WHITELIST' enables automatic whitelisting.

     Additional flags are available for defining the algorithm to split
     the message into tokens ("tokenizer") and "training mode".  *Note
     flags-dspam::, for a complete list of these.  All these are
     optional, any missing values will be read from the DSPAM
     "configuration file".

     The configuration file must always be present.  Its full file name
     must be stored in the global variable 'dspam_config'.  There is no
     default value, so make sure this variable is initialized.  If a
     specific profile section should be read, store the name of that
     profile in the variable 'dspam_profile'.

     When called to process or classify the message, 'dspam' returns an
     integer code of the class of the message.  The value 'DSR_ISSPAM'
     means that this message was classified as spam.  The value
     'DSR_ISINNOCENT' means it is a clean ("ham") message.

     The probability and confidence values are returned in global
     variables 'dspam_probability' and 'dspam_confidence'.  Since MFL
     lacks floating-point data type, both variables keep integers,
     obtained from the corresponding floating point values by shifting
     the decimal point 'dspam_prec' digits to the right and rounding the
     resulting value to the nearest integer.  The same method is used in
     'spamc' function (*note sa-floating-point-conversion::).  The
     default value for 'dspam_prec' variable is 3.  You can use the
     'sa_format_score' function to convert these values to strings
     representing floating point numbers, e.g.:

          require 'dspam'
          require 'sa'

          prog eom
          do
            if dspam(current_message(), DSM_PROCESS | DSM_SIGNATURE)
                 == DSR_ISSPAM
              header_add("X-DSPAM-Result", "Spam")
            else
              header_add("X-DSPAM-Result", "Innocent")
            fi
            header_add("X-DSPAM-Probability",
                       sa_format_score(dspam_probability, dspam_prec))
            header_add("X-DSPAM-Confidence",
                       sa_format_score(dspam_confidence, dspam_prec))
            header_add("X-DSPAM-Signature", dspam_signature)
          done

     Optional CLASS_SOURCE argument is used when training the DSPAM
     classifier.  It is a bitwise OR of the message class and message
     source values.  "Message class" specifies the class this message
     belongs to.  Possible values are 'DSR_ISSPAM', for spam messages,
     and 'DSR_ISINNOCENT', for clean messages.  "Message source" informs
     DSPAM where this message comes from.  The value 'DSS_ERROR' means
     the message was previously misclassified by DSPAM. The value
     'DSS_CORPUS' indicates the message comes from a corpus feed.
     Finally, the value 'DSS_INOCULATION' means that the message is in
     pristine form, and should be trained as an inoculation.
     "Inoculation" is a more intense mode of training, usually used on
     honeypots.

     The following example calls 'dspam' to train the classifier on the
     current message if it was sent to a honeypot address, and uses
     'dspam' to analyze the message class otherwise.  The 'honeypot'
     variable is supposed to be set elsewhere in the code (e.g.  in the
     'envrcpt' handler):

          prog eom
          do
            number res
            if honeypot
              set res dspam(current_message(), DSM_PROCESS,
                            DSR_ISSPAM | DSS_INOCULATION)
              discard
            else
              if dspam(current_message(), DSM_PROCESS | DSM_SIGNATURE)
                       == DSR_ISSPAM
                header_add("X-DSPAM-Result", "Spam")
              else
                header_add("X-DSPAM-Result", "Innocent")
              fi
              header_add("X-DSPAM-Probability",
                         sa_format_score(dspam_probability, dspam_prec))
              header_add("X-DSPAM-Confidence"
                         sa_format_score(dspam_confidence, dspam_prec))
              header_add("X-DSPAM-Signature", dspam_signature)
            fi
          done

* Menu:

* flags-dspam::       DSPAM Operation Modes and Flags.
* class-dspam::       DSPAM Class and Source Bits.
* vars-dspam::        DSPAM Global Variables.


File: mailfromd.info,  Node: flags-dspam,  Next: class-dspam,  Up: DSPAM

5.29.2.1 DSPAM Operation Modes and Flags.
.........................................

The tables below summarize flags which can be used in the MODE_FLAGS
argument to 'dspam' function.  The argument is a bitwise OR of
"operation mode", "flags", "tokenizer" and "training mode" bits.  Only
one operation mode bit can be used.  Flags, tokenizer and training mode
are optional.  Any number of flags, but no more than one tokenizer type
and one training mode bit are allowed.  Missing values will be supplied
from the configuration file.

Mode                   Meaning
--------------------------------------------------------------------------
DSM_PROCESS            Process message
DSM_CLASSIFY           Classify message only (do not write changes)

Table 5.2: DSPAM Operation modes

Flag                   Meaning
--------------------------------------------------------------------------
DSF_SIGNATURE          Create a signature
DSF_NOISE              Use Bayesian Noise Reduction
DSF_WHITELIST          Use Automatic Whitelisting

Table 5.3: DSPAM flags

Constant               Meaning
--------------------------------------------------------------------------
DSZ_WORD               Use "WORD" tokenizer
DSZ_CHAIN              Use "CHAIN" tokenizer
DSZ_SBPH               Use "SBPH" tokenizer
DSZ_OSB                Use "OSB" tokenizer

Table 5.4: DSPAM Tokenizer bits

Mode                   Meaning
--------------------------------------------------------------------------
DST_TEFT               Train Everything
DST_TOE                Train-on-Error
DST_TUM                Train-until-Mature

Table 5.5: DSPAM Training Modes


File: mailfromd.info,  Node: class-dspam,  Next: vars-dspam,  Prev: flags-dspam,  Up: DSPAM

5.29.2.2 DSPAM Class and Source Bits
....................................

The tables below summarize flags which can be used in the CLASS_SOURCE
argument to 'dspam' function.  The argument is a bitwise OR of
"classification" and "source" bits.  At most one classification and one
source bit can be given.  If not supplied, 'DSR_NONE|DSS_NONE' is used.

   The classification flags are also used as the return code, as shown
in the following table.

Mode                   As return value           As argument
---------------------------------------------------------------------------
DSR_NONE               N/A                       Classify message
DSR_ISSPAM             Message is spam           Learn as spam
DSR_ISINNOCENT         Message is innocent       Learn as innocent

Table 5.6: DSPAM Classification

Source                 Meaning
--------------------------------------------------------------------------
DSS_NONE               No classification source (use only with
                       DSR_NONE)
DSS_ERROR              Misclassification by libdspam
DSS_CORPUS             Message came from a corpus feed
DSS_INOCULATION        Message inoculation

Table 5.7: DSPAM Source


File: mailfromd.info,  Node: vars-dspam,  Prev: class-dspam,  Up: DSPAM

5.29.2.3 DSPAM Global Variables
...............................

Following global variables affect the behavior of the 'dspam' function:

 -- Built-in variable: string dspam_config
     Name of the DSPAM configuration file.  You must set this variable
     prior to calling 'dspam'.  There is no default value.

 -- Built-in variable: string dspam_profile
     Name of the configuration profile to be used.  If empty (the
     default), use global configuration settings.

 -- Built-in variable: string dspam_user
     Name of the user on behalf of which 'dspam' is called.  Default is
     empty (no user).

 -- Built-in variable: string dspam_group
     Name of the user group on behalf of which 'dspam' is called.
     Default is empty (no group).

 -- Built-in variable: number dspam_prec
     Number of decimal digits to retain in the 'dspam_probability' and
     'dspam_confidence' values.  *Note dspam probability and
     confidence::, for more information and examples.

   Before returning, 'dspam' stores additional information in the
following variables:

 -- Built-in variable: string dspam_signature
     Signature of the classified message.  This variable is initialized
     if 'DSF_SIGNATURE' bit is set in the MODE_FLAGS argument (*note
     dspam classify example::),

 -- Built-in variable: number dspam_probability
     Spam probability value converted to integer by shifting decimal
     point 'dspam_prec' positions to the right and rounding the
     resulting number.  *Note dspam probability and confidence::, for
     more information and examples.

 -- Built-in variable: number dspam_confidence
     Spam confidence converted to integer using the same algorithm as
     for 'dspam_probability'.  *Note dspam probability and confidence::,
     for more information and examples.


File: mailfromd.info,  Node: ClamAV,  Prev: DSPAM,  Up: Interfaces to Third-Party Programs

5.29.3 ClamAV
-------------

 -- Built-in Function: boolean clamav (number MSG, string URL)
     Pass the message MSG to the ClamAV daemon at URL.  Return 'true' if
     it detects a virus in it.  Return virus name in 'clamav_virus_name'
     global variable.

     The 'clamav' function can signal the following exceptions:
     'e_failure' if failed to connect to the server, 'e_url' if the
     supplied URL is invalid and 'e_range' if the supplied port number
     is out of the range 1-65535.

     An example usage:

          prog eom
          do
            if clamav(current_message(), "tcp://192.168.10.1:6300")
              reject 550 5.7.0 "Infected with %clamav_virus_name"
            fi
          done


File: mailfromd.info,  Node: Rate limiting functions,  Next: Greylisting functions,  Prev: Interfaces to Third-Party Programs,  Up: Library

5.30 Rate limiting functions
============================

 -- Built-in Function: number rate (string KEY, number SAMPLE-INTERVAL,
          [number MIN-SAMPLES, number THRESHOLD])

     Returns the mail sending rate for KEY per SAMPLE-INTERVAL.
     Optional MIN-SAMPLES, if supplied, specifies the minimal number of
     mails needed to obtain the statistics.  The default is 2.  Optional
     THRESHOLD controls rate database updates.  If the observed rate
     (per SAMPLE-INTERVAL seconds) is higher than the THRESHOLD, the hit
     counters for that key are not incremented and the database is not
     updated.  Although the THRESHOLD argument is optional(1), its use
     is strongly encouraged.  Normally, the value of THRESHOLD equals
     the value compared with the return from RATE, as in:

            if rate("$f-$client_addr", rate_interval, 4, maxrate) > maxrate
              tempfail 450 4.7.0 "Mail sending rate exceeded.  Try again later"
            fi

     This function is a low-level interface.  Instead of using it
     directly, we advise to use the 'rateok' function, described below.

 -- Library Function: boolean rateok (string KEY, number
          SAMPLE-INTERVAL, number THRESHOLD,
     [number MIN-SAMPLES])

     To use this function, require the 'rateok' module (*note
     Modules::), e.g.: 'require rateok'.

     The 'rateok' function returns 'True' if the mail sending rate for
     KEY, computed for the interval of SAMPLE-INTERVAL seconds is less
     than the THRESHOLD.  Optional MIN-SAMPLES parameter supplies the
     minimal number of mails needed to obtain the statistics.  It
     defaults to 4.

   *Note Sending Rate::, for a detailed description of the 'rateok' and
its use.  The 'interval' function (*note interval::) is often used in
the second argument to 'rateok' or 'rate'.

 -- Built-in Function: boolean tbf_rate (string KEY, number COST, number
          SAMPLE-INTERVAL, number BURST-SIZE)

     This function implements a classical token bucket filter algorithm.
     Tokens are added to the bucket identified by the KEY at constant
     rate of 1 token per SAMPLE-INTERVAL microseconds, to a maximum of
     BURST-SIZE tokens.  If no bucket is found for the specified key, a
     new bucket is created and initialized to contain BURST-SIZE tokens.
     If the bucket contains COST or more tokens, COST tokens are removed
     from it and 'tbf_rate' returns 'True'.  Otherwise, the function
     returns 'False'.

     For a detailed description of the Token Bucket Algorithm and its
     use to limit mail rates, see *note TBF::.

   ---------- Footnotes ----------

   (1) It is made optional in order to provide backward compatibility
with the releases of mailfromd prior to 5.0.93.


File: mailfromd.info,  Node: Greylisting functions,  Next: Special test functions,  Prev: Rate limiting functions,  Up: Library

5.31 Greylisting functions
==========================

 -- Built-in Function: boolean greylist (string KEY, number INTERVAL)

     Returns 'True' if the KEY is found in the greylist database
     (controlled by 'database greylist' configuration file statement,
     *note conf-database::).  The argument INTERVAL gives the
     greylisting interval in seconds.  The function stores the number of
     seconds left to the end of greylisting period in the global
     variable 'greylist_seconds_left'.  *Note Greylisting::, for a
     detailed explanation.

     The function 'greylist' can signal 'e_dbfailure' exception.

 -- Built-in Function: boolean is_greylisted (string KEY
     Returns 'True' if the KEY is still greylisted.  If 'true' is
     returned, the function also stores the number of seconds left to
     the end of greylisting period in the global variable
     'greylist_seconds_left'.

     This function is available only if Con Tassios implementation of
     greylisting is used.  *Note greylisting types::, for a discussion
     of available greylisting implementations.  *Note greylist::, for a
     way to switch to Con Tassios implementation.


File: mailfromd.info,  Node: Special test functions,  Next: Mail Sending Functions,  Prev: Greylisting functions,  Up: Library

5.32 Special Test Functions
===========================

 -- Library Function: boolean portprobe (string HOST, [number PORT])
 -- Library Function: boolean listens (string HOST, [number PORT])
     Returns 'true' if the IP address or host name given by HOST
     argument listens on the port number PORT (default 25).

     This function is defined in the module 'portprobe'.

 -- Built-in Function: boolean validuser (string NAME)
     Returns 'true' if authenticity of the user NAME is confirmed using
     mailutils authentication system.  *Note Local Account
     Verification::, for more details.

 -- Library Function: boolean valid_domain (string DOMAIN)

     Returns 'true' if the domain name DOMAIN has a corresponding A
     record or if it has any 'MX' records, i.e.  if it is possible to
     send mail to it.

     To use this function, require the 'valid_domain' module (*note
     Modules::):

          require valid_domain

 -- Library Function: number heloarg_test (string ARG, string REMOTE_IP,
          string LOCAL_IP)

     Verify if an argument of 'HELO' ('EHLO') command is valid.  To use
     this function, require the 'heloarg_test' module (*note Modules::).

     Arguments:

     ARG
          'HELO' ('EHLO') argument.  Typically, the value of '$s'
          Sendmail macro;

     REMOTE_IP
          IP address of the remote client.  Typically, the value of
          '$client_addr' Sendmail macro;

     LOCAL_IP
          IP address of this SMTP server;

     The function returns a number describing the result of the test, as
     described in the following table.

     Code                          Meaning
     --------------------------------------------------------------------------
     HELO_SUCCESS                  ARG successfully passes all tests.
     HELO_MYIP                     ARG is our IP address.
     HELO_IPNOMATCH                ARG is an IP, but it does not match the
                                   remote party IP address.
     HELO_ARGNORESOLVE             ARG is an IP, but it does not resolve.
     HELO_ARGNOIP                  ARG is in square brackets, but it is not
                                   an IP address.
     HELO_ARGINVALID               ARG is not an IP address and does not
                                   resolve to one.
     HELO_MYSERVERIP               ARG resolves to our server IP.
     HELO_IPMISMATCH               ARG does not resolve to the remote client
                                   IP address.


File: mailfromd.info,  Node: Mail Sending Functions,  Next: Blacklisting Functions,  Prev: Special test functions,  Up: Library

5.33 Mail Sending Functions
===========================

The mail sending functions are new interfaces, introduced in version
3.1.

   The underlying mechanism for sending mail, called "mailer", is
specified by '--mailer' command line option.  This global setting can be
overridden using the last optional argument to a particular function.
In any case, the mailer is specified in the form of a URL.

   "Mailer URL" begins with a protocol specification.  Two protocol
specifications are currently supported: 'sendmail' and 'smtp'.  The
former means to use a 'sendmail'-compatible program to send mails.  Such
a program must be able to read mail from its standard input and must
support the following options:

'-oi'
     Do not treat '.' as message terminator.

'-f ADDR'
     Use ADDR as the address of the sender.

'-t'
     Get recipient addresses from the message.

   These conditions are met by most existing MTA programs, such as
'exim' or 'postfix' (to say nothing of 'sendmail' itself).

   Following the protocol specification is the "mailer location", which
is separated from it with a colon.  For the 'sendmail' protocol, the
mailer location sets the full file name of the Sendmail-compatible MTA
binary, for example:

     sendmail:/usr/sbin/sendmail

   A special form of a sendmail URL, consisting of protocol
specification only ('sendmail:') is also allowed.  It means "use the
sendmail binary from the '_PATH_SENDMAIL' macro in your
'/usr/include/paths.h' file".  This is the default mailer.

   The 'smtp' protocol means to use an SMTP server directly.  In this
case the mailer location consists of two slashes, followed by the IP
address or host name of the SMTP server, and, optionally, the port
number.  If the port number is present, it is separated from the rest of
URL by a colon.  For example:

     smtp://remote.server.net
     smtp://remote.server.net:24

 -- Built-in Function: void send_mail (string MSG [, string TO, string
          FROM, string MAILER])

     Sends message MSG to the email address TO.  The value of MSG must
     be a valid RFC 2822 message, consisting of headers and body.
     Optional argument TO can contain several email addresses.  In this
     case the message will be sent to each recipient specified in TO.
     If it is not specified, recipient addresses will be obtained from
     the message headers.

     Other optional arguments are:

     FROM
          Sets the sender address.  By default '<>' is used.

     MAILER
          The URL of the mailer to use

     Sample usage:

              set message <<- EOT
                    Subject: Test message
                    To: Postmaster <postmaster@gnu.org.ua>
                    From: Mailfromd <devnull@gnu.org.ua>
                    X-Agent: %__package__ (%__version__)

                    Dear postmaster,

                    This is to notify you that our /etc/mailfromd.mf
                    needs a revision.
                    --
                    Mailfromd filter administrator
              EOT
              send_mail(message, "postmaster@gnu.org.ua")

 -- Built-in Function: void send_text (string TEXT, string HEADERS [,
          string TO, string FROM, string MAILER])
     A more complex interface to mail sending functions.

     Mandatory arguments:
     TEXT
          Text of the message to be sent.

     HEADERS
          Headers for the message.

     Optional arguments:
     TO
          Recipient email addresses.

     FROM
          Sender email address.

     MAILER
          URL of the mailer to use.

     The above example can be rewritten using 'send_text' as follows:

              set headers << -EOT
                    Subject: Test message
                    To: Postmaster <postmaster@gnu.org.ua>
                    From: Mailfromd <devnull@gnu.org.ua>
                    X-Agent: %__package__ (%__version__)
              EOT
              set text <<- EOT
                    Dear postmaster,

                    This is to notify you that our /etc/mailfromd.mf
                    needs a revision.
                    --
                    Mailfromd filter administrator
              EOT
              send_text(text, headers, "postmaster@gnu.org.ua")

 -- Built-in Function: void send_message (number MSG [string TO, string
          FROM, string MAILER])
     Send the message identified by descriptor MSG (*note Message
     functions::).

     Optional arguments are:

     TO
          Recipient email addresses.

     FROM
          Sender email address.

     MAILER
          URL of the mailer to use.

 -- Built-in Function: void send_dsn (string TO, string SENDER, string
          RCPT, string TEXT [, string HEADERS, string FROM, string
          MAILER])
     This is an experimental interface which will change in the future
     versions.  It sends a message disposition notification (RFC 2298,
     RFC 1894), of type 'deleted' to the email address TO.  Arguments
     are:

     TO
          Recipient email address.

     SENDER
          Original sender email address.

     RCPT
          Original recipient email address.

     TEXT
          Notification text.

     Optional arguments:
     HEADERS
          Message headers

     FROM
          Sender address.

     MAILER
          URL of the mailer to use.

 -- Built-in Function: void create_dsn (string SENDER, string RCPT,
          string TEXT [, string HEADERS, string FROM])
     Creates DSN message and returns its descriptor.  Arguments are:

     SENDER
          Original sender email address.

     RCPT
          Original recipient email address.

     TEXT
          Notification text.

     HEADERS
          Message headers

     FROM
          Sender address.


File: mailfromd.info,  Node: Blacklisting Functions,  Next: SPF Functions,  Prev: Mail Sending Functions,  Up: Library

5.34 Blacklisting Functions
===========================

The functions described in this subsection allow to check whether the
given IP address is listed in certain "black list" DNS zone.

 -- Library Function: boolean match_dnsbl (string ADDRESS, string ZONE,
          string RANGE)

     This function looks up ADDRESS in the DNS blacklist zone ZONE and
     checks if the return falls into the given RANGE of IP addresses.

     It is intended as a replacement for the Sendmail macros 'dnsbl' and
     'enhdnsbl'.

     To use 'match_dnsbl', require the 'match_dnsbl' module (*note
     Modules::).

     Arguments:

     ADDRESS
          IP address of the SMTP server to be tested.

     ZONE
          FQDN of the DNSbl zone to test against.

     RANGE
          The range of IP addresses in CIDR notation or the word 'ANY',
          which stands for '127.0.0.0/8'.

     The function returns 'true' if dns lookup for ADDRESS in the zone
     DNSBL yields an IP that falls within the range, specified by CIDR.
     Otherwise, it returns 'false'.

     This function raises the following exceptions: 'e_invip' if ADDRESS
     is invalid and 'e_invcidr' if CIDR is invalid.

 -- Library Function: boolean match_rhsbl (string EMAIL, string ZONE,
          string RANGE)

     This function checks if the IP address, corresponding to the domain
     part of EMAIL is listed in the RHS DNS blacklist zone ZONE, and if
     so, whether its record falls into the given range of IP addresses
     RANGE.

     It is intended as a replacement for the Sendmail macro 'rhsbl' by
     Derek J. Balling.

     To use this function, require the 'match_rhsbl' module (*note
     Modules::).

     Arguments:

     EMAIL
          E-mail address, whose domain name should be tested (usually,
          it is '$f')

     ZONE
          Domain name of the RHS DNS blacklist zone.

     RANGE
          The range of IP addresses in CIDR notation.


File: mailfromd.info,  Node: SPF Functions,  Next: DKIM,  Prev: Blacklisting Functions,  Up: Library

5.35 SPF Functions
==================

"Sender Policy Framework", or SPF for short, is an extension to SMTP
protocol that allows to identify forged identities supplied with the
'MAIL FROM' and 'HELO' commands.  The framework is explained in detail
in RFC 4408 (<http://tools.ietf.org/html/rfc4408>) and on the SPF
Project Site (http://www.openspf.org/).  The following description is a
short introduction only, and the users are encouraged to refer to the
original specification for the detailed description of the framework.

   The domain holder publishes an "SPF record" - a special DNS resource
record that contains a set of rules declaring which hosts are, and are
not, authorized to use a domain name for 'HELO' and 'MAIL FROM'
identities.  This resource record is usually of type 'TXT'.(1)

   The MFL script can verify if the identity matches the published SPF
record by calling 'check_host' function and analyzing its return code.
The function can be called either in 'helo' or in 'envfrom' handler.
Its arguments are:

IP
     The IP address of the SMTP client that is emitting the mail.
     Usually it is '$client_addr'.

DOMAIN
     The domain that provides the sought-after authorization
     information; Normally it is the domain portion of the 'MAIL FROM'
     or 'HELO' identity.

SENDER
     The 'MAIL FROM' identity.

HELO_DOMAIN
     The 'HELO' identity.

MY_DOMAIN
     The SMTP domain served by the local server.

   The function returns a numeric result code.  For convenience, all
possible return values are defined as macros in module 'spf.mf'.  The
table below describes each value along with the recommended actions for
it:

'None'
     A result of 'None' means that no records were published by the
     domain or that no checkable sender domain could be determined from
     the given identity.  The checking software cannot ascertain whether
     or not the client host is authorized.  Such a message can be
     subject to further checks that will decide about its fate.

'Neutral'
     The domain owner has explicitly stated that he cannot or does not
     want to assert whether or not the IP address is authorized.  This
     result must be treated exactly like 'None'; the distinction between
     them exists only for informational purposes

'Pass'
     The client is authorized to send mail with the given identity.  The
     message can be subject to further policy checks with confidence in
     the legitimate use of the identity or it can be accepted in the
     absence of such checks.

'Fail'
     The client is not authorized to use the domain in the given
     identity.  The proper action in this case can be to mark the
     message with a header explicitly stating it is spam, or to reject
     it outright.

     If you choose to reject such mails, we suggest to use 'reject 550
     5.7.1', as recommended by RFC 4408.  The reject can return either a
     default explanation string, or the one supplied by the domain that
     published the SPF records, as in the example below:

            reject 550 5.7.1 "SPF check failed:\n%spf_explanation"

     (for the description of 'spf_explanation', *note spf_explanation::)

'SoftFail'
     The domain believes the host is not authorized but is not willing
     to make that strong of a statement.  This result code should be
     treated as somewhere in between a 'Fail' and a 'Neutral'.  It is
     not recommended to reject the message based solely on this result.

'TempError'
     A transient error occurred while performing SPF check.  The proper
     action in this case is to accept or temporarily reject the message.
     If you choose the latter, we suggest to use SMTP reply code of
     '451' and DSN code '4.4.3', for example:

            tempfail 451 4.4.3
                     "Transient error while performing SPF verification"

'PermError'
     This result means that the domain's published records could not be
     correctly interpreted.  This signals an error condition that
     requires manual intervention to be resolved, as opposed to the
     'TempError' result.

   The following example illustrates the use of SPF verification in
'envfrom' handler:

     require 'status'
     require 'spf'

     prog envfrom
     do
       switch check_host($client_addr, domainpart($f), $f, $s)
       do
       case Fail:
         string text ""
         if spf_explanation != ""
           set text "%text\n%spf_explanation"
         fi
         reject 550 5.7.1 "SPF MAIL FROM check failed: %text"

       case Pass:
         accept

       case TempError:
         tempfail 451 4.4.3
                  "Transient error while performing SPF verification"

       default:
         on poll $f do
         when success:
           accept
         when not_found or failure:
           reject 550 5.1.0 "Sender validity not confirmed"
         when temp_failure:
           tempfail 450 4.7.0 "Temporary failure during sender verification"
         done
       done
     done

   The SPF support is implemented in MFL in two layers: a built-in layer
that provides basic support, and a library layer that provides a
convenience wrapper over the library function.

   The library layer is implemented in the module 'spf.mf' (*note
Modules::).

   The rest of this node describes available SPF functions and
variables.

 -- Built-in Function: number spf_check_host (string IP, string DOMAIN,
          string SENDER, string HELO_DOMAIN, string MY_DOMAIN)

     This function is the basic implementation of the 'check_host'
     function, defined in RFC 4408, chapter 4.  It fetches SPF records,
     parses them, and evaluates them to determine whether a particular
     host (IP) is or is not permitted to send mail from a given email
     address (SENDER).  The function returns an "SPF result code".

     Arguments are:

     IP
          The IP address of the SMTP client that is emitting the mail.
          Usually it is '$client_addr'.

     DOMAIN
          The domain that provides the sought-after authorization
          information; Normally it is the domain portion of the 'MAIL
          FROM' or 'HELO' identity.

     SENDER
          The 'MAIL FROM' identity.

     HELO_DOMAIN
          The 'HELO' identity.

     MY_DOMAIN
          The SMTP domain served by the local server.

     Before returning the 'spf_check_host' function stores additional
     information in global variables:

     'spf_explanation'
          If the result code is 'Fail', this variable contains the
          explanation string as returned by the publishing domain,
          prefixed with the value of the global variable
          'spf_explanation_prefix'.

          For example, if 'spf_explanation_prefix' contains 'The domain
          %{o} explains: ', and the publishing domain 'example.com'
          returns the explanation string 'Please see
          http://www.example.com/mailpolicy.html', than the value of
          'spf_explanation' will be:

               The domain example.com explains:
               Please see http://www.example.com/mailpolicy.html

          (see RFC 4408 (http://tools.ietf.org/html/rfc4408), chapter 8,
          for the description of SPF macro facility).

     'spf_mechanism'
          Name of the SPF mechanism that decided about the result code
          of the SPF record.  If one or more 'include' or 'redirect'
          mechanisms were traversed before arriving at that mechanism,
          their values are appended in the reverse order.

 -- Built-in Function: number spf_test_record (string RECORD, string IP,
          string DOMAIN, string SENDER, string HELO_DOMAIN, string
          MY_DOMAIN)

     Evaluate SPF record RECORD as if it were published by DOMAIN.  The
     rest of arguments are the same as for 'spf_check_host' above.

     This function is designed primarily for testing and debugging
     purposes.  You would hardly need to use it.

     The 'spf_test_record' function sets the same global variables as
     'spf_check_host'.

 -- Library Function: number check_host (string IP, string DOMAIN,
          string SENDER, string HELO)

     This function implements the 'check_host' function, defined in RFC
     4408, chapter 4.  It fetches SPF records, parses them, and
     evaluates them to determine whether a particular host (IP) is or is
     not permitted to send mail from a given email address (SENDER).
     The function returns an "SPF result code".

     This function is a wrapper over the built-in 'spf_check_host'.

     The arguments are:

     IP
          The IP address of the SMTP client that is emitting the mail.
          Usually it is the same as the value of '$client_addr'.

     DOMAIN
          The domain that provides the sought-after authorization
          information; Normally it is the domain portion of the 'MAIL
          FROM' or 'HELO' identity.

     SENDER
          The 'MAIL FROM' identity.

     HELO
          The 'HELO' identity.

 -- Library Function: string spf_status_string (number CODE)
     Converts numeric SPF result CODE to its string representation.

 -- Built-in variable: string spf_explanation
     If 'check_host' (or 'spf_check_host' or 'spf_test_record') returned
     'Fail', this variable contains the explanation string as returned
     by the publishing domain, prefixed with the value of the global
     variable 'spf_explanation_prefix'.

     For example, if 'spf_explanation_prefix' contains 'The domain %{o}
     explains: ', and the publishing domain 'example.com' returns the
     explanation string 'Please see
     http://www.example.com/mailpolicy.html', than the value of
     'spf_explanation' will be:

          The domain example.com explains:
          Please see http://www.example.com/mailpolicy.html

 -- Built-in variable: string spf_mechanism
     Set to the name of a SPF mechanism that decided about the result
     code of the SPF record.

 -- Built-in variable: string spf_explanation_prefix
     The prefix to be appended to the explanation string before storing
     it in the 'spf_explanation' variable.  This string can contain
     valid SPF macros (see RFC 4408
     (http://tools.ietf.org/html/rfc4408), chapter 8), for example:

          set spf_explanation_prefix "%{o} explains: "

     The default value is '""' (an empty string).

   ---------- Footnotes ----------

   (1) Although RFC 4408 introduces a special 'SPF' record type for this
purpose, it is not yet widely used.  As of version 8.14, MFL does not
support 'SPF' DNS records.


File: mailfromd.info,  Node: DKIM,  Next: Sockmaps,  Prev: SPF Functions,  Up: Library

5.36 DKIM
=========

DKIM or "DomainKeys Identified Mail" is an email authentication method
that allows recipients to verify if an email was authorized by the owner
of the domain that email claims to originate from.  It does so by adding
a digital signature which is verified using a public key published as a
DNS TXT record.  For technical details about DKIM, please refer to RFC
6376 (<http://tools.ietf.org/html/rfc6376>).

   MFL provides functions for DKIM signing and verification.

 -- Built-in Function: number dkim_verify (number MSG)
     Verifies the message MSG (a message descriptor, obtained from a
     call to 'current_message', 'mailbox_get_message',
     'message_from_stream' or a similar function).

     Return value (constants defined in the 'status' module):

      -- dkim_verify status: DKIM_VERIFY_OK
          The message contains one or more 'DKIM-Signature' headers and
          one of them verified successfully.

      -- dkim_verify status: DKIM_VERIFY_PERMFAIL
          The message contains one or more 'DKIM-Signature' headers, all
          of which failed to verify.

      -- dkim_verify status: DKIM_VERIFY_TEMPFAIL
          The message was not signed using DKIM, or the DNS query to
          obtain the public key failed, or an internal software error
          occurred during verification.

     The following two global variables are always set upon return from
     this function: 'dkim_explanation' and 'dkim_explanation_code'.
     These can be used to clarify the verification result to the end
     user.  The variable 'dkim_signing_algorithm' is initialized with
     the name of the algorithm used to sign the message.

     Upon successful return, the variable 'dkim_verified_signature' is
     set to the value of the successfully verified DKIM signature.

 -- Built-in variable: string dkim_signing_algorithm
     Name of the algorithm used to sign the message (either 'rsa-sha1'
     or 'rsa-sha256').  If the algorithm was not specified (e.g.  the
     signature is malformed), this variable is assigned an empty value.

 -- Built-in variable: string dkim_explanation
     An explanatory message clarifying the verification result.

 -- Built-in variable: number dkim_explanation_code
     A numeric code corresponding to the 'dkim_explanation' string.  Its
     possible values are defined in 'status.mf':

      -- DKIM explanation code: DKIM_EXPL_OK
          'DKIM verification passed'

      -- DKIM explanation code: DKIM_EXPL_OK
          'DKIM verification passed'

      -- DKIM explanation code: DKIM_EXPL_NO_SIG
          'No DKIM signature'

      -- DKIM explanation code: DKIM_EXPL_INTERNAL_ERROR
          'internal error'

      -- DKIM explanation code: DKIM_EXPL_SIG_SYNTAX
          'signature syntax error'

      -- DKIM explanation code: DKIM_EXPL_SIG_MISS
          'signature is missing required tag'

          According to the DKIM specification, required tags are: 'a=',
          'b=', 'bh=', 'd=', 'h=', 's=', 'v='.

      -- DKIM explanation code: DKIM_EXPL_DOMAIN_MISMATCH
          'domain mismatch'

          The domain part of the 'i=' tag does not match and is not a
          subdomain of the domain listed in the 'd=' tag.

      -- DKIM explanation code: DKIM_EXPL_BAD_VERSION
          'incompatible version'

          Incompatible DKIM version listed in the 'v=' tag.

      -- DKIM explanation code: DKIM_EXPL_BAD_ALGORITHM
          'unsupported signing algorithm'

          Either the 'a=' tag of the DKIM signature contains an
          unsupported algorithm (currently supported algorithms are:
          'rsa-sha1' and 'rsa-sha256') or this algorithm, while being
          supported by 'mailfromd', is not listed in the 'h=' tag of the
          public DKIM key.

      -- DKIM explanation code: DKIM_EXPL_BAD_QUERY
          'unsupported query method'

          The 'q=' tag of the public DKIM key contains something other
          than 'dns/txt'.

      -- DKIM explanation code: DKIM_EXPL_FROM
          'From field not signed'

      -- DKIM explanation code: DKIM_EXPL_EXPIRED
          'signature expired'

      -- DKIM explanation code: DKIM_EXPL_DNS_UNAVAIL
          'public key unavailable'

      -- DKIM explanation code: DKIM_EXPL_DNS_NOTFOUND
          'public key not found'

      -- DKIM explanation code: DKIM_EXPL_KEY_SYNTAX
          'key syntax error'

      -- DKIM explanation code: DKIM_EXPL_KEY_REVOKED
          'key revoked'

      -- DKIM explanation code: DKIM_EXPL_BAD_BODY
          'body hash did not verify'

      -- DKIM explanation code: DKIM_EXPL_BAD_BASE64
          'can't decode b= tag'

          Base64 decoding of the 'b=' tag failed.

      -- DKIM explanation code: DKIM_EXPL_BAD_SIG
          'signature did not verify'

      -- DKIM explanation code: DKIM_EXPL_BAD_KEY_TYPE
          'unsupported public key type'

          The 'k=' tag of the public DKIM signature contains a value,
          other than 'rsa'.

 -- Built-in variable: string dkim_verified_signature
     Upon successful return from the 'dkim_verify' function, this
     variable holds the value of the successfully verified DKIM header.
     This value is unfolded and all whitespace is removed from it.

   An example of using the 'dkim_verify' function:

     require status
     require dkim

     prog eom
     do
       string result
       switch dkim_verify(current_message())
       do
          case DKIM_VERIFY_OK:
              set result "pass; verified for " .
                         dkim_verified_signature_tag('i')
          case DKIM_VERIFY_PERMFAIL:
              set result "fail (%dkim_explanation)"
          case DKIM_VERIFY_TEMPFAIL:
              set result "neutral"
       done
       header_add("X-Verification-Result", "dkim=%result")
     done

   The 'dkim' module defines convenience functions for manipulating with
DKIM signatures:

 -- Library Function: dkim_signature_tag (string SIG, string TAG)
     Extracts the value of the tag TAG from the DKIM signature SIG.
     Signature must be normalized by performing the header unwrapping
     and removing whitespace characters.

     If the tag was not found, returns empty string, unless TAG is one
     of the tags listed in the table below.  If any of these tags are
     absent, the following values are returned instead:

     Tag                    Default value
     -------------------------------------------------------------------
     c                      'simple/simple'
     q                      'dns/txt'
     i                      '@' + the value of the 'd' tag.

 -- Library Function: string dkim_verified_signature_tag (string TAG)
     Returns the value of tag TAG from the 'dkim_verified_signature'
     variable.

 -- Built-in Function: void dkim_sign (string D, string S, string
          KEYFILE, [ string CH, string CB, string HEADERS, string ALGO
          ])

     This function is available only in the 'eom' handler.

     Signs the current message.  _Notice_, that no other modification
     should be attempted on the message after calling this function.
     Doing so would make the signature invalid.

     Mandatory arguments:

     D
          Name of the domain claiming responsibility for an introduction
          of a message into the mail stream.  It is also known as the
          signing domain identifier (SDID).

     S
          The selector name.  This value, along with D identifies the
          location of the DKIM public key necessary for verifying the
          message.  The public key is stored in the DNS TXT record for

                 S._domainkey.D

     KEYFILE
          Name of the disk file that keeps the private key for signing
          the message.  The file must be in PEM format.

     Optional arguments:

     CH
          Canonicalization algorithm for message headers.  Valid values
          are: 'simple' and 'relaxed'.  'simple' is the default.

     CB
          Canonicalization algorithm for message body.  Valid and
          default values are the same as for CH.

     HEADERS
          A colon-separated list of header field names that identify the
          header fields that must be signed.  Optional whitespace is
          allowed at either side of each colon separator.  Header names
          are case-insensitive.  This list must contain at least the
          'From' header.

          It may contain names of headers that are not present in the
          message being signed.  This provides a way to explicitly
          assert the absence of a header field.  For example, if HEADERS
          contained 'X-Mailer' and that header is not present in the
          message being signed, but is added by a third party later, the
          signature verification will fail.

          Similarly, listing a header field name once more than the
          actual number of its occurrences in a message allows you to
          prevent any further additions.  For example, if there is a
          single 'Comments' header field at the time of signing, putting
          'Comments:Comments:' in the HEADERS parameter is sufficient to
          prevent any surplus 'Comments' headers from being added later
          on.

          Multiple instances of the same header name are allowed.  They
          mean that multiple occurrences of the corresponding header
          field will be included in the header hash.  When such multiple
          header occurrences are referenced, they will be presented to
          the hashing algorithm in the reverse order.  E.g.  if the
          HEADER list contained 'Received:Received') and the current
          message contained three 'Received' headers:

               Received: A
               Received: B
               Received: C

          then these headers will be signed in the following order:

               Received: C
               Received: B

          The default value for this parameter, split over multiple
          lines for readability, is as follows:

             * "From:From:"
             * "Reply-To:Reply-To:"
             * "Subject:Subject:"
             * "Date:Date:"
             * "To:"
             * "Cc:"
             * "Resent-Date:"
             * "Resent-From:"
             * "Resent-To:"
             * "Resent-Cc:"
             * "In-Reply-To:"
             * "References:"
             * "List-Id:"
             * "List-Help:"
             * "List-Unsubscribe:"
             * "List-Subscribe:"
             * "List-Post:"
             * "List-Owner:"
             * "List-Archive"

     ALGO
          Signing algorithm: either 'rsa-sha256' or 'rsa-sha1'.  Default
          is 'rsa-sha256'.

   An example of using this function:

     precious string domain "example.org"
     precious string selector "s2048"
     prog eom
     do
       dkim_sign("example.org", "s2048", "/etc/pem/my-private.pem",
                 "relaxed", "relaxed", "from:to:subject")
     done

Note on interaction of dkim_sign with Sendmail
----------------------------------------------

When sending a signed message, it is critical that no other
modifications be applied to the message after it has been signed.
Unfortunately, it is not always the case when 'mailfromd' is used with
'Sendmail'.  Before sending the message over SMTP, 'Sendmail' reformats
the headers that contain a list of email addresses, by applying to them
a procedure called in its parlance "commaization".  The following
headers are modified: 'Apparently-To', 'Bcc', 'Cc',
'Disposition-Notification-To', 'Errors-To', 'From', 'Reply-To',
'Resent-Bcc', 'Resent-Cc', 'Resent-From', 'Resent-Reply-To',
'Resent-Sender', 'Resent-To', 'Sender', 'To'.  Thus, if your 'dkim_sign'
includes any of these in the signature (which is the default) and some
of them happen to be formatted other way than the one 'Sendmail'
prefers, the DKIM signature would not verify on the recipient side.  To
prevent this from happening, 'dkim_sign' mimics the Sendmail behavior
and reformats those headers before signing the message.  This should
ensure that the message signed and the message actually sent are the
same.  This default behavior is controlled by the following global
variable:

 -- Built-in variable: number dkim_sendmail_commaize
     "Commaize" the address headers (see the list above) of the message
     the same way Sendmail does, and then sign the resulting message.

     The default value is 1 ('true').  You can set it to 0 ('false') if
     this behavior is not what you want (e.g.  if you are using
     'postfix' or some other MTA).

Note on interaction of dkim_sign with MMQ
-----------------------------------------

The functions 'header_add' and 'header_insert' (*note Header
modification functions::) as well as the 'add' action (*note header
manipulation::) cannot interact properly with 'dkim_sign' due to the
shortcomings of the Milter API. If any of these was called, 'dkim_sign'
will throw the 'e_badmmq' exception with the diagnostics following
diagnostics:

     MMQ incompatible with dkim_sign: OP on H, value V

where OP is the operation code ('ADD HEADER' or 'INSERT HEADER'), H is
the header name and V is its value.

   The following example shows one graceful way of handling such
exception:

     prog eom
     do
         try
         do
             dkim_sign("example.org", "s2048", "/etc/pem/my-private.pem")
         done
         catch e_badmmq
         do
             # Purge the message modification queue
             mmq_purge()
             # and retry
             dkim_sign("example.org", "s2048", "/etc/pem/my-private.pem")
         done
     done

   *Note Message modification queue::, for a discussion of the message
modification queue.

* Menu:

* Setting up a DKIM record::


File: mailfromd.info,  Node: Setting up a DKIM record,  Up: DKIM

5.36.1 Setting up a DKIM record
-------------------------------

Follow these steps to set up your own DKIM record:

  1. Generate a key pair:

     Use the 'openssl genrsa' command.  Run:

          openssl genrsa -out private.pem 2048

     The last argument is the size of the private key to generate in
     bits.

  2. Extract the public key:

          openssl rsa -in private.pem -pubout -outform PEM -out public.pem

  3. Set up a DKIM record in your domain:

     A DKIM record is a TXT type DNS record that holds the public key
     part for verifying messages.  Its format is defined in RFC 4871(1).
     The label for this record is composed as follows:

            S._domainkey.D

     where D is your domain name, and S is the selector you chose to
     use.  You will use these two values as parameters to the
     'dkim_sign' function in your 'eom' handler.  E.g.  if your domain
     in 'example.com' and selector is 's2048', then the DKIM TXT record
     label is 's2048._domainkey.example.com'.

     The public key file generated in step 2 will have the following
     contents:

          -----BEGIN PUBLIC KEY-----
          BASE64
          -----END PUBLIC KEY-----

     where BASE64 is the key itself in base64 encoding.  The minimal
     DKIM TXT record will be:

          "v=DKIM1; p=BASE64"

     The only mandatory "tag" is in fact 'p='.  The use of 'v=' is
     recommended.  More tags can be added as needed.  In particular,
     while testing the DKIM support, it is advisable to add the 't=y'
     tag.

   ---------- Footnotes ----------

   (1) <https://tools.ietf.org/html/rfc4871>


File: mailfromd.info,  Node: Sockmaps,  Next: NLS Functions,  Prev: DKIM,  Up: Library

5.37 Sockmap Functions
======================

Socket map ("sockmap" for short) is a special type of database used in
Sendmail and MeTA1.  It uses a simple server/client protocol over INET
or UNIX stream sockets.  The server listens on a socket for queries.
The client connects to the server and sends it a query, consisting of a
"map name" and a "key" separated by a single space.  Both map name and
key are sequences of non-whitespace characters.  The map name serves to
identify the type of the query.  The server replies with a response
consisting of a "status indicator" and "result", separated by a single
space.  The result part is optional.

   For example, following is the query for key 'smith' in map 'aliases':

     11:aliases news,

   A possible reply is:

     18:OK root@domain.net,

   This reply means that the key 'news' was found in the map, and the
value corresponding to that key is 'root@domain.net'.

   The following reply means the key was not found:

     8:NOTFOUND,

   For a detailed description of the sockmap protocol, see *note
(smap)Protocol::.

   The MFL library provides two primitives for dealing with sockmaps.
Both primitives become available after requiring the 'sockmap' module.

 -- Library Function: string sockmap_lookup (number FD, string MAP,
          string KEY)
     This function look ups the KEY in the MAP.  The FD refers to the
     sockmap to use.  It must be obtained as a result of a previous call
     to 'open' with the URL of the sockmap as its first argument (*note
     open: I/O functions.).  For example:

            number fd open("@ unix:///var/spool/meta1/smap/socket")
            string ret sockmap_query(fd, "aliases", $rcpt_to)
            if ret matches "OK (.+)"
              set alias \1
            fi
            close(fd)

 -- Library Function: string sockmap_single_lookup (string URL, string
          MAP, string KEY)
     This function connects to the sockmap identified by the URL,
     queries for KEY in MAP and closes the connection.  It is useful
     when you need to perform only a single lookup on the sockmap.


File: mailfromd.info,  Node: NLS Functions,  Next: Syslog Interface,  Prev: Sockmaps,  Up: Library

5.38 National Language Support Functions
========================================

The "National Language Support" functions allow you to write your
scripts in such a way, that any textual messages they display are
automatically translated to your native language, or, more precisely, to
the language required by your current locale.

   This section assumes the reader is familiar with the concepts of
program "internationalization" and "localization".  If not, please refer
to *note The Purpose of GNU 'gettext': (gettext)Why, before reading
further.

   In general, internationalization of any MFL script follows the same
rules as described in the 'GNU gettext manual'.  First of all, you
select the program "message domain", i.e.  the identifier of a set of
translatable messages your script contain.  This identifier is then used
to select appropriate translation.  The message domain is set using
'textdomain' function.  For the purposes of this section, let's suppose
the domain name is 'myfilter'.  All NLS functions are provided in the
'nls' module, which you need to require prior to using any of them.

   To find translations of textual message to the current locale, the
underlying 'gettext' mechanism will look for file
'DIRNAME/LOCALE/LC_MESSAGES/DOMAINNAME.mo', where DIRNAME is the message
catalog hierarchy name, LOCALE is the locale name, and DOMAINNAME is the
name of the message domain.  By default DIRNAME is
'/usr/local/share/locale', but you may change it using 'bindtextdomain'
function.  The right place for this initial NLS setup is in the 'begin'
block (*note begin/end::).  To summarize all the above, the usual NLS
setup will look like:

     require nls

     begin
     do
       textdomain("myfilter")
       bindtextdomain("myfilter", "/usr/share/locale");
     done

   For example, given the settings above, and supposing the environment
variable 'LC_ALL' is set to 'pl', translations will be looked in file
'/usr/share/locale/pl/LC_MESSAGES/myfilter.mo'.

   Once this preparatory work is done, you can request each message to
be translated by using 'gettext' function, or '_' (underscore) macro.
For example, the following statement will produce translated textual
description for '450' response:

     tempfail 450 4.1.0 _("Try again later")

   Of course it assumes that the appropriate 'myfile.mo' file already
exists.  If it does not, nothing bad happens: in this case the macro '_'
(as well as 'gettext' function) will simply return its argument
unchanged, so that the remote party will get the textual message in
English.

   The 'mo' files are binary files created from 'po' source files using
'msgfmt' utility, as described in *note Producing Binary MO Files:
(gettext)Binaries.  In turn, the format of 'po' files is described in
*note The Format of PO Files: (gettext)PO Files.

 -- Built-in Function: string bindtextdomain (string DOMAIN, string
          DIRNAME)
     This function sets the base directory of the hierarchy containing
     message catalogs for a given message domain.

     DOMAIN is a string identifying the textual domain.  If it is not
     empty, the base directory for message catalogs belonging to domain
     DOMAIN is set to DIRNAME.  It is important that DIRNAME be an
     absolute pathname; otherwise it cannot be guaranteed that the
     message catalogs will be found.

     If DOMAIN is '""', 'bindtextdomain' returns the previously set base
     directory for domain DOMAIN.

   The rest of this section describes the NLS functions supplied in the
'nls' module.

 -- Built-in Function: string dgettext (string DOMAIN, string MSGID)
     'dgettext' attempts to translate the string MSGID into the
     currently active locale, according to the settings of the textual
     domain DOMAIN.  If there is no translation available, 'dgettext'
     returns MSGID unchanged.

 -- Built-in Function: string dngettext (string DOMAIN, string MSGID,
          string MSGID_PLURAL, number N)
     The 'dngettext' functions attempts to translate a text string into
     the language specified by the current locale, by looking up the
     appropriate singular or plural form of the translation in a message
     catalog, set for the textual domain DOMAIN.

     *Note Additional functions for plural forms: (gettext)Plural forms,
     for a discussion of the plural form handling in different
     languages.

 -- Library Function: string textdomain (string DOMAIN)
     The 'textdomain' function sets the current message domain to
     DOMAIN, if it is not empty.  In any case the function returns the
     current message domain.  The current domain is 'mailfromd'
     initially.  For example, the following sequence of 'textdomain'
     invocations will yield:

          textdomain("") => "mailfromd"
          textdomain("myfilter") => "myfilter"
          textdomain("") => "myfilter"

 -- Library Function: string gettext (string MSGID)
     'gettext' attempts to translate the string MSGID into the currently
     active locale, according to the settings of the current textual
     domain (set using 'textdomain' function).  If there is no
     translation available, 'gettext' returns MSGID unchanged.

 -- Library Function: string ngettext (string MSGID, string
          MSGID_PLURAL, number N)
     The 'ngettext' functions attempts to translate a text string into
     the language specified by the current locale, by looking up the
     appropriate singular or plural form of the translation in a message
     catalog, set for the current textual domain.

     *Note Additional functions for plural forms: (gettext)Plural forms,
     for a discussion of the plural form handling in different
     languages.


File: mailfromd.info,  Node: Syslog Interface,  Next: Debugging Functions,  Prev: NLS Functions,  Up: Library

5.39 Syslog Interface
=====================

The basic means for outputting diagnostic messages is the 'echo'
instruction (*note Echo::), which sends its arguments to the currently
established logging channel.  In daemon mode, the latter is normally
connected to syslog, so any echoed messages are sent there with the
facility selected in mailfromd configuration and priority 'info'.

   If you want to send a message to another facility and/or priority,
use the 'syslog' function:

 -- Built-in Function: void syslog (number PRIORITY, string TEXT)
     Sends TEXT to syslog.  The priority argument is formed by ORing the
     facility and the level values (explained below).  The facility
     level is optional.  If not supplied, the currently selected logging
     facility is used.

   The facility specifies what type of program is logging the message,
and the level indicates its relative severity.  The following symbolic
facility values are declared in the 'syslog' module: 'LOG_KERN',
'LOG_USER', 'LOG_MAIL', 'LOG_DAEMON', 'LOG_AUTH', 'LOG_SYSLOG',
'LOG_LPR', 'LOG_NEWS', 'LOG_UUCP', 'LOG_CRON', 'LOG_AUTHPRIV', 'LOG_FTP'
and 'LOG_LOCAL0' through 'LOG_LOCAL7'

   The declared severity levels are: 'LOG_EMERG', 'LOG_ALERT',
'LOG_CRIT', 'LOG_ERR', 'LOG_WARNING', 'LOG_NOTICE', 'LOG_INFO' and
'LOG_DEBUG'.


File: mailfromd.info,  Node: Debugging Functions,  Prev: Syslog Interface,  Up: Library

5.40 Debugging Functions
========================

These functions are designed for debugging the MFL programs.

 -- Built-in Function: void debug (string SPEC)
     Enable debugging.  The value of SPEC sets the debugging level.
     *Note debugging level specification::, for a description of its
     format.

     For compatibility with previous versions, this function is also
     available under the name 'mailutils_set_debug_level'.

 -- Built-in Function: number debug_level ([string SRCNAME])
     This function returns the debugging level currently in effect for
     the source module SRCNAME, or the global debugging level, if called
     without arguments.

     For example, if the program was started with
     '--debug='all.trace5;engine.trace8'' option, then:

          debug_level() => 127
          debug_level("engine") => 1023
          debug_level("db") => 0

 -- Built-in Function: boolean callout_transcript ([boolean VALUE])
     Returns the current state of the callout SMTP transcript.  The
     result is 1 if the transcript is enabled and 0 otherwise.  The
     transcript is normally enabled either by the use of the
     '--transcript' command line option (*note SMTP transcript::) or via
     the 'transcript' configuration statement (*note transcript:
     conf-server.).

     The optional VALUE, supplies the new state for SMTP transcript.
     Thus, calling 'callout_transcript(0)' disables the transcript.

     This function can be used in bracket-like fashion to enable
     transcript for a certain part of MFL program, e.g.:

          number xstate callout_transcript(1)
          on poll $f do
            ...
          done
          set xstate callout_transcript(0)

     Note, that the use of this function (as well as the use of the
     '--transcript' option) makes sense only if callouts are performed
     by the 'mailfromd' daemon itself.  It will not work if a dedicated
     callout server is used for that purpose (*note calloutd::).

 -- Built-in Function: string debug_spec ([string CATNAMES, bool
          SHOWUNSET])
     Returns the current debugging level specification, as given by
     '--debug' command line option or by the 'debug' configuration
     statement (*note conf-debug::).

     If the argument SRCNAMES is specified, it is treated as a
     semicolon-separated list of categories for which the debugging
     specification is to be returned.

     For example, if 'mailfromd' was started with
     '--debug=all.trace5;spf.trace1;engine.trace8;db.trace0', then:

          debug_spec() => "all.trace5,engine.trace8"
          debug_spec("all;engine") => "all.trace5,engine.trace8"
          debug_spec("engine;db") => "db.trace0;engine.trace8"
          debug_spec("prog") => ""

     When called without arguments, 'debug_spec' returns only those
     categories which have been set, as shown in the first example
     above.

     Optional SHOWUNSET parameters controls whether to return unset
     module specifications.  To print all debugging specifications,
     whether set or not, use

          debug_spec("", 1)

   These three functions are intended to complement each other.  The
calls to 'debug' can be placed around some piece of code you wish to
debug, to enable specific debugging information for this code fragment
only.  For example:

         /* Save debugging level for 'dns.c' source */
         set dlev debug_spec("dns", 1)
         /* Set new debugging level */
         debug("dns.trace8")
         .
         .
         .
         /* Restore previous level */
         debug(dlev)

 -- Built-in Function: void program_trace (string MODULE)
     Enable tracing for a set of modules given in MODULE argument.
     *Note --trace-program::, for a description of its format.

 -- Built-in Function: void cancel_program_trace (string MODULE)
     Disable tracing for given modules.

   This pair of functions is also designed to be used together in a
bracket-like fashion.  They are useful for debugging 'mailfromd', but
are not advised to use otherwise, since tracing slows down the execution
considerably.

 -- Built-in Function: void stack_trace ()
     Generate a stack trace in this point.  *Note tracing runtime
     errors::, for the detailed description of stack traces.

   The functions below are intended mainly for debugging MFL run-time
engine and for use in 'mailfromd' testsuite.  You will hardly need to
use them in your programs.

 -- Built-in Function: void _expand_dataseg (number N)
     Expands the run-time data segment by at least N words.

 -- Built-in Function: number _reg (number R)
     Returns the value of the register R at the moment of the call.
     Symbolic names for run-time registers are provided in the module
     '_register':

     Name                   Register
     --------------------------------------------------------------------------
     REG_PC                 Program counter
     REG_TOS                Top of stack
     REG_TOH                Top of heap
     REG_BASE               Frame base
     REG_REG                General-purpose accumulator
     REG_MATCHSTR           Last matched string pointer

 -- Built-in Function: void _wd ([number N])
     Enters a time-consuming loop and waits there for N seconds (by
     default - indefinitely).  The intention is to facilitate attaching
     to 'mailfromd' with the debugger.  Before entering the loop, a
     diagnostic message is printed on the 'crit' facility, informing
     about the PID of the process and suggesting the command to be used
     to attach to it, e.g.:

          mailfromd: process 21831 is waiting for debug
          mailfromd: to attach: gdb -ex 'set variable mu_wd::_count_down=0'
           /usr/sbib/mailfromd 21831


File: mailfromd.info,  Node: Using MFL Mode,  Next: Mailfromd Configuration,  Prev: Library,  Up: Top

6 Using the GNU Emacs MFL Mode
******************************

MFL sources are usual ASCII files and you may edit them with any editor
you like.  However, the best choice for this job (as well as for many
others) is, without doubt, GNU Emacs.  To ease the work of editing
script files, the 'mailfromd' package provides a special Emacs mode,
called "MFL mode".

   The elisp source file providing this mode, 'mfl-mode.el', is
installed automatically, provided that GNU Emacs is present on your
machine.  To enable the mode, add the following lines to your Emacs
setup file (either system-wide 'site-start.el', or your personal one,
'~/.emacs'):

     (autoload 'mfl-mode "mfl-mode")
     (setq auto-mode-alist (append auto-mode-alist
                            '(("/etc/mailfromd.mf" . mfl-mode)
                              ("\\.mf$" . mfl-mode))))

   The first directive loads the MFL mode, and the second one tells
Emacs to apply it to any file whose name ends in '/etc/mailfromd.mf'(1)
or in a '.mf' suffix.

   MFL mode provides automatic indentation and syntax highlighting for
MFL sources.  The default indentation setup is the same as the one used
throughout this book:

   * Handler and function definitions start at column 1;
   * A block statement, i.e. 'do', 'done', 'if', 'else', 'elif' and
     'fi', occupies a line by itself, with the only exception that 'do'
     after an 'on' statement is located on the same line with it;
   * A 'do' statement that follows function or handler definition is
     placed in column 1.
   * Each subsequent level of nesting is indented two columns to the
     right (*note mfl-basic-offset::).
   * A closing statement ('done', 'else', 'elif', 'fi') is placed at the
     same column as the corresponding opening statement;
   * Branch statements ('case' and 'when') are placed in the same column
     as their controlling keyword ('switch' and 'on', correspondingly
     (*note mfl-case-line-offset::).
   * Loop substatements (*note Loops::) are offset 5 columns to the
     right from the controlling 'loop' keyword.  (*note
     mfl-loop-statement-offset::).  Continuation statements within loop
     header are offset 5 columns from the indentation of their
     controlling keyword, either 'for' or 'while' (*note
     mfl-loop-continuation-offset::).

   The mode provides two special commands that help navigate through the
complex filter scripts:

'C-M-a'
     Move to the beginning of current function or handler definition.

'C-M-e'
     Move to the end of current function or handler definition.

   Here, "current function or handler" means the one within which your
cursor currently stays.

   You can use 'C-M-e' repeatedly to walk through all function and
handler definitions in your script files.  Similarly, repeatedly
pressing 'C-M-a' will visit all the definitions in the opposite
direction (from the last up to the very first one).

   Another special command, 'C-c C-c', allows to verify the syntax of
your script file.  This command runs 'mailfromd' in syntax check mode
(*note Testing Filter Scripts::) and displays its output in a secondary
window, which allows to navigate through eventual diagnostic messages
and to jump to source locations described by them.

   All MFL mode settings are customizable.  To change any of them, press
'M-x customize' and visit 'Environment/Unix/Mfl' customization group.
This group offers two subgroups: 'Mfl Lint group' and 'Mfl Indentation
group'.

   'Mfl Lint group' controls invocation of mailfromd by 'C-c C-c'.  This
group contains two variables:

 -- MFL-mode setting: mfl-mailfromd-command
     The 'mailfromd' to be invoked.  By default, it is 'mailfromd'.  You
     will have to change it, if 'mailfromd' cannot be found using 'PATH'
     environment variable, or if you wish to pass it some special
     options.  However, do not include '--lint' or '-I' options in this
     variable.  The '--lint' option is given automatically, and include
     paths are controlled by 'mfl-include-path' variable (see below).

 -- MFL-mode setting: mfl-include-path
     A list of directories to be appended to 'mailfromd' include search
     path (*note include search path::).  By default it is empty.

   'Mfl Indentation group' controls automatic indentation of MFL
scripts.  This group contains the following settings:

 -- MFL-mode setting: mfl-basic-offset
     This variable sets the basic indentation increment.  It is set to
     2, by default, which corresponds to the following indentation
     style:

          prog envfrom
          do
            if $f = ""
              accept
            else
              ...
            fi
          done

 -- MFL-mode setting: mfl-case-line-offset
     Indentation offset for 'case' and 'when' lines, relative to the
     column of their controlling keyword.  The default is 0, i.e.:

          switch x
          do
          case 0:
            ...
          default:
            ...
          done

 -- MFL-mode setting: mfl-returns-offset
     Indentation offset of 'returns' and 'alias' statements, relative to
     the controlling 'func' keyword.  The default value is 2, which
     corresponds to:

          func foo()
            alias bar
            returns string

 -- MFL-mode setting: mfl-comment-offset
     Indentation increment for multi-line comments.  The default value
     is 1, which makes:

             /* first comment line
                second comment line */

 -- MFL-mode setting: mfl-loop-statement-offset
     Indentation increment for parts of a 'loop' statement.  The default
     value is 5, which corresponds to the following style:

          loop for STMT,
               while COND,
               INCR
          do

 -- MFL-mode setting: mfl-loop-continuation-offset
     If any of the 'loop' parts occupies several lines, the indentation
     of continuation lines relative to the first line is controlled by
     'mfl-loop-continuation-offset', which defaults to 5:

          loop for set n 0
                    set z 1,
               while n != 10
                    or z != 2,
               set n n + 1

   ---------- Footnotes ----------

   (1) This will match most existing installations.  In the unlikely
case that your '$sysconfdir' does not end in '/etc', you will have to
edit the directive accordingly.


File: mailfromd.info,  Node: Mailfromd Configuration,  Next: Invocation,  Prev: Using MFL Mode,  Up: Top

7 Configuring 'mailfromd'
*************************

Upon startup, 'mailfromd' checks if the file '/etc/mailfromd.conf'
exists.(1)  If it does, the program attempts to retrieve its
configuration settings from that file.

   The 'mailfromd.conf' file must be written in the "GNU mailutils
configuration format", as described in *note Configuration File Syntax:
(mailutils)conf-syntax.  This format can be summarized as follows:

Comments
     Inline comments begin with '//' or '#' and end at the end of the
     line.  Multiline comments are delimited by '/*' and '*/'.
     Multiline comments cannot be nested, but can contain inline comment
     markers.
Empty lines and whitespace
     Empty lines are ignored.  Whitespace characters (i.e.  horizontal,
     vertical space, and newline) are ignored, except as they serve to
     separate tokens.
Statements
     A statement consists of a keyword and a value, separated by
     whitespace.  Statements terminate with a semicolon.  E.g.

          pidfile /var/run/mailfromd.pid;
Block statements
     A block statement consists of a keyword and a list of statements
     enclosed in '{' and '}' characters.  Optional "label" can appear
     between the keyword and opening curly brace.  E.g.:

          logging {
            syslog on;
            facility mail;
          }

     Block statement is not required to terminate with a semicolon,
     although it is allowed to.
File Inclusion
     The 'include' statement causes inclusion of the file listed as its
     value:

          include /usr/share/mailfromd/config.inc;

   The 'mailfromd.conf' file is used by all programs that form the
'mailfromd' package, i.e.  'mailfromd', 'calloutd', 'mfdbtool', and
'pmult'.  Since the sets of statements understood by each of them
differ, special syntactic means are provided to separate
program-specific configurations from each other.

   First of all, if the argument to 'include' is a directory, then the
program will search that directory for a file with the same name as the
base name of the program itself.  If found, this file will be loaded
after finishing parsing the 'mailfromd.conf' file.  Otherwise, this
statement is ignored.

   Secondly, the special block statement 'program TAG' is processed only
if TAG matches the base name of the program being run.  Again, it is
processed after the main 'mailfromd.conf' file.

   Thus, if you need to provide configuration for the 'calloutd'
component, there are two ways of doing so.  First, you can place it to a
file named 'calloutd' placed in a separate directory (say,
'/etc/mailfromd.d'), and use the name of that directory in a 'include'
statement in the main configuration file:

     include /etc/mailfromd.d;

   Secondly, you can use the 'program' statement as follows:

     program calloutd {
       ...
     }

* Menu:

* conf-types::      Special Configuration Data Types
* conf-base::       Base Mailfromd Configuration
* conf-resolver::   DNS Resolver Configuration
* conf-server::     Server Configuration
* conf-milter::     Milter Connection Configuration
* conf-debug::      Logging and Debugging configuration
* conf-timeout::    Timeout Configuration
* conf-callout::    Call-out Configuration
* conf-priv::       Privilege Configuration
* conf-database::   Database Configuration
* conf-runtime::    Runtime Constants
* conf-mailutils::  Standard Mailutils Statements

   ---------- Footnotes ----------

   (1) The exact location is determined at compile time: the '/etc'
directory is the system configuration directory set when building
'mailfromd' (*note Building::).


File: mailfromd.info,  Node: conf-types,  Next: conf-base,  Up: Mailfromd Configuration

7.1 Special Configuration Data Types
====================================

In addition to the usual data types (*note (mailutils)Statements::),
'mailfromd' configuration introduces the following two special ones:

time interval specification
     The "time interval specification" is a string that defines an
     interval, much the same way we do this in English: it consists of
     one or more pairs 'number'-'time unit'.  For example, the following
     are valid interval specifications:

          1 hour
          2 hours 35 seconds
          1 year 7 months 2 weeks 2 days 11 hours 12 seconds

     The pairs can occur in any order, however unusual it may sound to a
     human ear, e.g. '2 days 1 year'.  If the 'time unit' is omitted,
     seconds are supposed.

Connection URL
     unix://FILE
     unix:FILE
     local://FILE
     local:FILE
          A named pipe (socket).

     inet://ADDRESS:PORT
     inet:PORT@ADDRESS
          An IPv4 connection to host ADDRESS at port PORT.  Port must be
          specified either as a decimal number or as a string
          representing the port name in '/etc/services'.

     inet6:PORT@ADDRESS
          An IPv6 connection to host ADDRESS at port PORT.  This port
          type is not yet supported.


File: mailfromd.info,  Node: conf-base,  Next: conf-resolver,  Prev: conf-types,  Up: Mailfromd Configuration

7.2 Base Mailfromd Configuration
================================

 -- Mailfromd Conf: script-file file
     Read filter script from FILE.  By default it is read from
     'SYSCONFDIR/mailfromd.mf'.

 -- Mailfromd Conf: setvar name value
     Initialize MFL variable NAME to VALUE.

 -- Mailfromd Conf: include-path path
     Add directories to the list of directories to be searched for
     header files.  *Note include search path::.

     Argument is a list of directory names separated by colons.

 -- Mailfromd Conf: state-directory dir
     Set program state directory.  *Note statedir::.

 -- Mailfromd Conf: relayed-domain-file file
     Append domain names from the named FILE to the list of relayed
     domains.  This list can be inspected from MFL script using the
     'relayed' function (*note relayed::).

     The FILE argument is either a single file name or a list of file
     names, e.g.:

          relayed-domain-file /etc/mail/sendmail.cw;
          relayed-domain-file (/etc/mail/sendmail.cw, /etc/mail/relay-domains);

 -- Mailfromd Conf: source-ip ipaddr
     Set source IP address for outgoing TCP connections.

 -- Mailfromd Conf: pidfile file
     Set the name of the file to store PID value in.  The file must be
     writable for the user or group 'mailfromd' runs as (*note
     conf-priv::).


File: mailfromd.info,  Node: conf-resolver,  Next: conf-server,  Prev: conf-base,  Up: Mailfromd Configuration

7.3 DNS Resolver Configuration
==============================

DNS resolver settings are configured using the 'resolver' compound
statement:

     resolver {
       config FILENAME;
       max-cname-chain NUM;
     }

 -- resolver: config FILENAME
     Name of the resolver configuration file to use, instead of the
     default '/etc/resolv.conf'.

 -- resolver: max-cname-chain NUM
     Maximum allowed length of a DNS "CNAME chain" that will be
     followed.  A "CNAME chain" is a sequence of 'CNAME' records
     pointing to another 'CNAME's.  Although CNAME chains are not
     considered a good practice, many sites still use them.  By default
     the 'mailfromd' resolver allows at most one CNAME record pointing
     to a CNAME (this corresponds to 'max-cname-chain 2').  If you need
     to follow longer chains, raise this value.  Note however, that
     using values greater than 5 is not a good idea, anyway.


File: mailfromd.info,  Node: conf-server,  Next: conf-milter,  Prev: conf-resolver,  Up: Mailfromd Configuration

7.4 Server Configuration
========================

A single 'mailfromd' daemon can run several "servers".  These are
configured in the following statement:

     server TYPE {
       id NAME;
       listen URL;
       backlog NUM;
       max-instances NUM;
       single-process BOOL;
       reuseaddr BOOL;
       option LIST;
       default BOOL;
       callout URL;
       acl { ... }
     }

 -- Mailfromd Conf: server TYPE
     Define a server.  The TYPE is either 'milter' or 'callout'.  *Note
     SMTP Timeouts::, for a description of various types of servers.

     The substatements in the 'server' block provide parameters for
     configuring this server.

 -- server: id name
     Assign an identifier to this server.  This identifier is used as a
     suffix to syslog tag (*note syslog tag::) in messages related to
     this server.  For example, if a server block had the following
     statement in it:

          id main;

     then all messages related to this server will be marked with tag
     'mailfromd#main'.

     The part before the '#' is set using the 'tag' statement in
     'logging' block (*note Mailutils Configuration File:
     (mailutils)Logging Statement.).

 -- server: listen url
     Listen for connections on the given URL.  *Note milter port
     specification::, for a description of allowed URL formats.

     Example:

          listen inet://10.10.10.1:3331;

 -- server: backlog NUM
     Configures the size of the queue of pending connections.  Default
     value is 8.

 -- server: max-instances number
     Sets the maximum number of instances allowed for this server.

 -- server: single-process bool
     When set to 'yes', this server will run in "single-process" mode,
     i.e.  it will not fork sub-processes to serve requests.  This
     option is meant exclusively to assist in debugging 'mailfromd'.
     Don't use it for anything else but for debugging!

 -- server: reuseaddr bool
     When set to 'yes', 'mailfromd' will attempt to reuse existing
     socket addresses.  This is the default behavior.

   If the server TYPE is 'callout', the following statement is also
allowed:

 -- server: option LIST
     Configures server options.  As of version 8.14 only one option is
     defined:

     default
          Mark this server as the default one.  This means it will be
          used by every milter server that doesn't define the
          'callout-url' statement.

 -- server: default bool
     When set to 'yes', this server is marked as a default callout
     server for all milter servers declared in the configuration.  This
     is equivalent to 'option default'.

   if the server TYPE is 'milter', you can use the following statement
to query a remote callout server:

 -- server: callout url
     Use a callout server at URL (*note milter port specification::).

   You can also set a "global callout server", which will be used by all
milter servers that do not set the 'callout' statement:

 -- Mailfromd Conf: callout-url url
     Set global callout server.  *Note milter port specification::, for
     allowed URL formats.


File: mailfromd.info,  Node: conf-milter,  Next: conf-debug,  Prev: conf-server,  Up: Mailfromd Configuration

7.5 Milter Connection Configuration
===================================

 -- Mailfromd Conf: milter-timeout time
     Sets the timeout value for connection between the filter and the
     MTA.  Default value is 7210 seconds.  You normally do not need to
     change this value.

 -- Mailfromd Conf: acl
     This block statement configures "access control list" for incoming
     Milter connections.  *Note Mailutils Configuration File:
     (mailutils)ACL Statement, for a description of its syntax.  E.g.:

          acl {
            allow from 10.10.10.0/24;
            deny from any;
          }


File: mailfromd.info,  Node: conf-debug,  Next: conf-timeout,  Prev: conf-milter,  Up: Mailfromd Configuration

7.6 Logging and Debugging configuration
=======================================

 -- Mailfromd Conf: logger mech
     Set default logger mechanism.  Allowed values for MECH are:

     stderr
          Log everything to the standard error.

     syslog
          Log to syslog.

     syslog:async
          Log to syslog using the asynchronous syslog implementation.

     *Note Logging and Debugging::, for a detailed discussion.  See also
     *note Using non-blocking syslog: syslog-async, for information on
     how to set default syslog implementation at compile time.

 -- Mailfromd Conf: debug spec
     Set 'mailfromd' debug verbosity level.  The SPEC must be a valid
     debugging level specification (*note debugging level
     specification::).

 -- Mailfromd Conf: stack-trace bool
     Enables stack trace dumps on runtime errors.  This feature is
     useful for locating the source of an error, especially in complex
     scripts.  *Note tracing runtime errors::, for a detailed
     description.

 -- Mailfromd Conf: trace-actions bool
     Enable action tracing.  If BOOL is 'true', 'mailfromd' will log all
     executed actions.  *Note Logging and Debugging::, for a detailed
     description of action tracing.

 -- Mailfromd Conf: trace-program modlist
     Enable program instruction tracing for modules in MODLIST, a
     comma-separated list of source code modules, e.g.:

          trace-program (bi_io,bi_db);

     This statement enables tracing for functions from modules 'bi_io.c'
     and 'bi_db.c' (notice, that you need not give file suffixes).

     This tracing is useful for debugging 'mailfromd', but is not
     advised to use otherwise, since it is very time-costly.

 -- Mailfromd Conf: transcript bool
     Enable transcripts of call-out SMTP sessions.  *Note SMTP
     transcript::, for a detailed description of SMTP transcripts.


File: mailfromd.info,  Node: conf-timeout,  Next: conf-callout,  Prev: conf-debug,  Up: Mailfromd Configuration

7.7 Timeout Configuration
=========================

The SMTP timeouts used in callout sessions are configured via
'smtp-timeout' statement:

Syntax
------

     smtp-timeout TYPE {
       connection INTERVAL;
       initial-response INTERVAL;
       helo INTERVAL;
       mail INTERVAL;
       rcpt INTERVAL;
       rset INTERVAL;
       quit INTERVAL;
     }

 -- Mailfromd Conf: smtp-timeout TYPE
     Declare SMTP timeouts of the given TYPE, which may be 'soft' or
     'hard'.

     Callout SMTP sessions initiated by polling functions, are
     controlled by two sets of timeouts: 'soft' and 'hard'.  "Soft
     timeouts" are used by the mailfromd milter servers.  "Hard
     timeouts" are used by callout servers (*note callout server::).
     When a soft timeout is exceeded, the calling procedure is delivered
     an 'e_temp_failure' exception and the session is scheduled for
     processing by a callout server.  The latter re-runs the session
     using hard timeouts.  If a hard timeout is exceeded, the address is
     marked as 'not_found' and is stored in the cache database with that
     status.

     Normally, soft timeouts are set to shorter values, suitable for use
     in MFL scripts without causing excessive delays.  Hard timeouts are
     set to large values, as requested by RFC 2822 and guarantee
     obtaining a definite answer (see below for the default values).

Statements
----------

The TIME argument for all 'smtp-timeout' sub-statements is expressed in
time interval units, as described in *note time interval
specification::.

 -- smtp-timeout: connection time
     Sets initial connection timeout for callout tests.  If the
     connection is not established within this time, the corresponding
     callout function returns temporary failure.

 -- smtp-timeout: initial-response time
     Sets the time to wait for the initial SMTP response.

 -- smtp-timeout: helo time
     Timeout for a response to 'HELO' (or 'EHLO') command.

 -- smtp-timeout: mail time
     Timeout for a response to 'MAIL' command.

 -- smtp-timeout: rcpt time
     Timeout for a response to 'RCPT' command.

 -- smtp-timeout: rset time
     Timeout for a response to 'RSET' command.

 -- smtp-timeout: quit time
     Timeout for a response to 'QUIT' command.

Default Values
--------------

The default timeout settings are:

Timeout                              Soft               Hard
---------------------------------------------------------------------------
connection                           10s                5m
initial-response                     30s                5m
helo                                 I/O                5m
mail                                 I/O                10m
rcpt                                 I/O                5m
rset                                 I/O                5m
quit                                 I/O                2m

Table 7.1: Default SMTP timeouts

 -- Mailfromd Conf: io-timeout time
     Sets a general SMTP I/O operation timeout.  This timeout is used as
     the default for entries marked with 'I/O' in the above table.  The
     default is 3 seconds.


File: mailfromd.info,  Node: conf-callout,  Next: conf-priv,  Prev: conf-timeout,  Up: Mailfromd Configuration

7.8 Call-out Configuration
==========================

 -- Mailfromd Conf: ehlo-domain string
     Sets default domain used in 'EHLO' (or 'HELO') SMTP command when
     probing the remote host.  This value can be overridden by 'from'
     parameter to 'poll' command (*note poll::).

     This statement assigns the value STRING to the 'ehlo_domain'
     variable (*note ehlo_domain::), and is therefore equivalent to

          setvar ehlo_domain STRING;

 -- Mailfromd Conf: mail-from-address string
     Sets default email addresses used in 'MAIL FROM:' SMTP command when
     probing the remote host.  This value can be overridden by 'as'
     parameter to 'poll' command (*note poll::).

     This statement assigns the value STRING to the 'mailfrom_address'
     variable (*note mailfrom_address::), and is therefore equivalent to

          setvar mailfrom_address STRING;

 -- Mailfromd Conf: enable-vrfy bool
     Enables the use of SMTP VRFY statement prior to normal callout
     sequence.  If VRFY is supported by the remote server, 'mailfromd'
     relies on its reply and does not perform normal callout.

     The use of this statement is not recommended, because many existing
     VRFY implementations always return affirmative result, no matter is
     the requested email handled by the server or not.

     The default is 'enable-vrfy no', i.e. VRFY is disabled.


File: mailfromd.info,  Node: conf-priv,  Next: conf-database,  Prev: conf-callout,  Up: Mailfromd Configuration

7.9 Privilege Configuration
===========================

 -- Mailfromd Conf: user name
     Switch to this user's privileges after startup.  *Note Starting and
     Stopping::, for a discussion of the privileges 'mailfromd' runs
     under and the options that affect them.  See also 'group' below.

 -- Mailfromd Conf: group name
     Retain the supplementary group NAME when switching to user
     privileges.  By default 'mailfromd' clears the list of
     supplementary groups when switching to user privileges, but this
     statement allows to retain the given group.  It can be specified
     multiple times to retain several groups.  This option may be
     necessary to maintain proper access rights for various files.
     *Note Starting and Stopping::.


File: mailfromd.info,  Node: conf-database,  Next: conf-runtime,  Prev: conf-priv,  Up: Mailfromd Configuration

7.10 Database Configuration
===========================

Syntax
------

     database DBNAME {
       file NAME;
       enable BOOL;
       expire-interval INTERVAL;
       positive-expire-interval INTERVAL;
       negative-expire-interval INTERVAL;
     }

 -- Mailfromd Conf: database dbname
     The 'database' statement controls run-time parameters of a DBM
     database identified by DBNAME.  Allowed values for the latter are:
     'cache', 'rate' and 'greylist' for main cache, DNS lookup, sending
     rate and greylisting databases, correspondingly.

Statements
----------

 -- database: file name
     Set the database file name.

 -- database: enable bool
     Enable or disable this database.

 -- database: expire-interval time
     Set the expiration interval for this database DBNAME.  *Note time
     interval specification::, for a description of TIME format.

 -- database: positive-expire-interval time
     This statement is valid only for 'cache' database.  It sets the
     expiration interval for positive ('success') cache entries.

 -- database: negative-expire-interval time
     This statement is valid only for 'cache' database, where it sets
     expiration interval for negative ('not_found') cache entries.

Additional Statements
---------------------

 -- Mailfromd Conf: database-type TYPE
     Set default database type.  TYPE is one of the database types
     supported by mailutils (i.e., for Mailutils 3.0: 'gdbm', 'ndbm',
     'bdb', 'kc', and 'tc').  Run

          mailfromd --show-defaults | grep 'supported databases:'

     to get a list of type names supported by your build of 'mailfromd'.

 -- Mailfromd Conf: database-mode MODE
     Defines file mode for newly created database files.  MODE must be a
     valid file mode in octal.

 -- Mailfromd Conf: lock-retry-count number
     Set maximum number of attempts to acquire the lock.  The time
     between each two successive attempts is given by
     'lock-retry-timeout' statement (see below).  After the NUMBER of
     failed attempts, 'mailfromd' gives up.

 -- Mailfromd Conf: lock-retry-timeout time
     Set the time span between the two locking attempts.  Any valid time
     interval specification (*note time interval specification::) is
     allowed as argument.


File: mailfromd.info,  Node: conf-runtime,  Next: conf-mailutils,  Prev: conf-database,  Up: Mailfromd Configuration

7.11 Runtime Constants Configuration
====================================

 -- Mailfromd Conf: runtime { statements }
     The statements in the 'runtime' section configure various values
     used by MFL builtin functions.

 -- runtime: max-streams number
     Sets the maximum number of stream descriptors that can be opened
     simultaneously.  Default is 1024.  *Note I/O functions::.

 -- runtime: max-open-mailboxes number
     Sets the maximum number of available mailbox descriptors.  This
     value is used by MFL mailbox functions (*note Mailbox functions::).

 -- runtime: max-open-messages number
     Sets the maximum number of messages that can be opened
     simultaneously using the 'mailbox_get_message' function.  *Note
     Message functions::, for details.


File: mailfromd.info,  Node: conf-mailutils,  Prev: conf-runtime,  Up: Mailfromd Configuration

7.12 Standard Mailutils Statements
==================================

The following standard Mailutils statements are understood:

Statement              Reference
-------------------------------------------------------------------
auth                   *Note Mailutils Configuration File: (mailutils)auth statement.
debug                  *Note Mailutils Configuration File: (mailutils)debug statement.
include                *Note Mailutils Configuration File: (mailutils)include.
logging                *Note Mailutils Configuration File: (mailutils)logging statement.
mailer                 *Note Mailutils Configuration File: (mailutils)mailer statement.
locking                *Note Mailutils Configuration File: (mailutils)locking statement.


File: mailfromd.info,  Node: Invocation,  Next: MTA Configuration,  Prev: Mailfromd Configuration,  Up: Top

8 'Mailfromd' Command Line Syntax
*********************************

The 'mailfromd' binary is started from the command line using the
following syntax (brackets indicate optional parts):

     $ mailfromd [OPTIONS] [ASGN] [SCRIPT]

The meaning of each invocation part is described in the table below:

OPTIONS
     The command line options (*note options::).

ASGN
     Sendmail macro assignments.  These are currently meaningful only
     with the '--test' option (*note test mode::), but this may change
     in the future.  Each assignment has the form:

          VAR=VALUE

     where VAR is the name of a Sendmail macro and VALUE is the value to
     be assigned to it.

SCRIPT
     The file name of the filter script, if other than the default one.

* Menu:

* options::                     Command Line Options.
* Starting and Stopping::       How to Start and Shut Down the Daemon.


File: mailfromd.info,  Node: options,  Next: Starting and Stopping,  Up: Invocation

8.1 Command Line Options.
=========================

* Menu:

* Operation Modifiers::
* General Settings::
* Preprocessor Options::
* Timeout Control::
* Logging and Debugging Options::
* Informational Options::


File: mailfromd.info,  Node: Operation Modifiers,  Next: General Settings,  Up: options

8.1.1 Operation Modifiers
-------------------------

'--daemon'
     Run in daemon mode (default).

'--run[=START]'
     Load the script named in the command line and execute the function
     named START, or 'main', if START is not given.  *Note Run Mode::,
     for a detailed description of this feature.

'--show-defaults'
     Show compilation defaults.  *Note Databases::.

'-t[STATE]'
'--test[=STATE]'
     Run in test mode.  *Note Testing Filter Scripts::.  Default STATE
     is 'envfrom'.  This option implies '--stderr' (*note --stderr::).


File: mailfromd.info,  Node: General Settings,  Next: Preprocessor Options,  Prev: Operation Modifiers,  Up: options

8.1.2 General Settings
----------------------

'--callout-socket=STRING'
     Set socket for the default callout server.  This is mainly useful
     together with the '--mtasim' option.

'--foreground'
     Stay in foreground.  When given this option, 'mailfromd' will not
     disconnect itself from the controlling terminal and will run in the
     foreground.

'-g NAME'
'--group=NAME'

     Retain the group NAME when switching to user privileges.  *Note
     Starting and Stopping::.

     This option complements the 'group' configuration statement (*note
     group: conf-priv.).

'--include=DIR'
'-I DIR'
     Add the directory DIR to the list of directories to be searched for
     header files.  This will affect the functioning of '#include'
     statement.  *Note include::, for a discussion of file inclusion.

'--mailer=URL'
'-M URL'
     Set the URL of the mailer to use.  *Note Mail Sending Functions::.

'--mtasim'
     This option is reserved for use by 'mtasim' (*note mtasim::).

'-O[LEVEL]'
'--optimize[=LEVEL]'
     Set optimization level for code generator.  Two levels are
     implemented: '0', meaning no optimization, and '1', meaning full
     optimization.

'-p STRING'
'--port=STRING'
'--milter-socket=STRING'
     Set communication socket.  Overrides the 'listen' configuration
     statement, which you are advised to use instead (*note listen:
     conf-milter.).

'--pidfile=FILE'
     Set pidfile name.  Overrides the 'pidfile' configuration statement,
     which you are advised to use instead (*note pidfile: conf-base.).

'--relayed-domain-file=FILE'
     Read relayed domains from FILE.  Overrides the
     'relayed-domain-file' configuration statement (*note
     relayed-domain-file: conf-base.), which you are advised to use
     instead.  *Note Avoiding Verification Loops::, and the description
     of 'relayed' function (*note relayed::) for more information.

'--resolv-conf-file=FILE'
     Read resolver settings from FILE, instead of the default
     '/etc/resolv.conf'.

'--state-directory=DIR'
     Set new program state directory.  *Note Local state directory:
     statedir, for the description of this directory and its purposes.
     This option overrides the settings of 'state-directory'
     configuration statement, described in *note state-directory:
     conf-base.

'-S IP'
'--source-ip=IP'
     Set source address for TCP connections.  Overrides the 'source-ip'
     configuration statement, which you are advised to use instead
     (*note source-ip: conf-base.).

'-u NAME'
'--user NAME'
     Switch to this user privileges after startup.  Overrides the 'user'
     configuration file statement, which you are advised to use instead
     (*note user: conf-priv.).  Default user is 'mail'.

'-v VAR=VALUE'
'--variable VAR=VALUE'
     Assign VALUE to the global variable VAR.  The variable must be
     declared in your startup script.  *Note overriding initial
     values::, for a detailed discussion of this option.


File: mailfromd.info,  Node: Preprocessor Options,  Next: Timeout Control,  Prev: General Settings,  Up: options

8.1.3 Preprocessor Options
--------------------------

Following command line options control the preprocessor feature.  *Note
Preprocessor::, for a detailed discussion of these.

'--no-preprocessor'
     Do not run the preprocessor.

'--preprocessor=COMMAND'
     Use COMMAND as the external preprocessor instead of the default
     'm4'.

'-D NAME[=VALUE]'
'--define=NAME[=VALUE]'
     Define a preprocessor symbol NAME to have a value VALUE.

'-U NAME'
'--undefine=NAME'
     Undefine the preprocessor symbol NAME.

'-E'
     Stop after the preprocessing stage; do not run the compiler proper.
     The output is in the form of preprocessed source code, which is
     sent to the standard output.


File: mailfromd.info,  Node: Timeout Control,  Next: Logging and Debugging Options,  Prev: Preprocessor Options,  Up: options

8.1.4 Timeout Control
---------------------

*Note time interval specification::, for information on INTERVAL format.

'--milter-timeout=INTERVAL'
     Set MTA connection timeout.  Overrides 'milter-timeout' statement
     in the 'mailfromd' configuration file, which you are advised to use
     instead (*note milter-timeout: conf-milter.).


File: mailfromd.info,  Node: Logging and Debugging Options,  Next: Informational Options,  Prev: Timeout Control,  Up: options

8.1.5 Logging and Debugging Options
-----------------------------------

'--location-column'
'--no-location-column'
     Mention column number in error messages.  *Note location-column:
     Testing Filter Scripts.  Use '--no-location-column' to disable

'-d STRING'
'--debug=STRING'
     Set debugging level.  *Note Logging and Debugging::.

'--dump-code'
     Parse and compile the script file and dump the disassembled listing
     of the produced code to the terminal.  *Note Logging and
     Debugging::.

'--dump-grammar-trace'
     Enable debugging the script file parser.  While parsing the file,
     the detailed dump of the parser states and tokens seen will be
     output.

'--dump-lex-trace'
     Enable debugging the lexical analyzer.  While parsing the script
     file, the detailed dump of the lexer states and matched rules will
     be output.

'--dump-macros'
     Show Sendmail macros used in the script file.  The macro names are
     displayed as comma-separated lists, grouped by handler names.
     *Note Sendmail::, for a detailed description of this option and its
     usage.

'--dump-tree'
     Parse and compile the script file and dump the parse tree in a
     printable form to the terminal.

'--dump-xref'
     Print a cross-reference of variables used in the filter script.
     *Note Testing Filter Scripts::.

'-E'
     Stop after the preprocessing stage; do not run the compiler proper.
     The output is in the form of preprocessed source code, which is
     sent to the standard output.  *Note Preprocessor::.

'--lint'
     Check script file syntax and exit.  If the file is OK, return 0 to
     the shell, otherwise print appropriate messages to stderr and exit
     with code 78 ('configuration error').

'--single-process'
     Do not fork sub-processes to serve requests.  This option is meant
     to assist in debugging 'mailfromd'.  Don't use it for anything else
     but for debugging, as it terribly degrades performance!

'--stack-trace'
'--no-stack-trace'
     Add MFL stack trace information to runtime error output.  Overrides
     'stack-trace' configuration statement.  Use the '--no-stack-trace'
     to disable trace information.

     *Note tracing runtime errors::, for more information on this
     feature.

'--gacopyz-log=LEVEL'
     Set desired logging level for 'gacopyz' library (*note Gacopyz::).
     There are five logging levels.  The following table lists them in
     order of decreasing priority:

     fatal
          Log fatal errors.

     err
          Log error messages.

     warn
          Log warning messages.

     info
          Log informational messages.  In particular, this enables
          printing messages on each subprocess startup and termination,
          which look like that:

               Apr 28 09:00:11 host mailfromd[9411]: connect
                   from 192.168.10.1:50398
               Apr 28 09:00:11 host mailfromd[9411]: finishing
                   connection

          This level can be useful for debugging your scripts.

     debug
          Log debugging information.

     proto
          Log Milter protocol interactions.  This level prints huge
          amounts of information, in particular it displays dumps of
          each Milter packet sent and received.

     Although it is possible to set these levels independently of each
     other, it is seldom practical.  Therefore, the option
     '--gacopyz-log=LEVEL' enables all logging levels from LEVEL up.
     For example, '--gacopyz-log=warn' enables log levels 'warn', 'err'
     and 'fatal'.  It is the default.  If you need to trace each
     subprocess startup and shutdown, set '--gacopyz-log=info'.  Setting
     the logging level to 'proto' can be needed only for 'Gacopyz'
     developers, to debug the protocol.

     *Note Testing Filter Scripts::.

'--logger=MECH'
     Set logger mechanism (MECH is one of 'stderr', 'syslog',
     'syslog:async').  *Note Logging and Debugging::.

'--log-facility=FACILITY'
     Output logs to syslog FACILITY.

'--log-tag=STRING'
     Tag syslog entries with the given STRING, instead of the program
     name.

'--source-info'
'--no-source-info'
     Include C source information in debugging messages.  This is
     similar to setting 'line-info yes' in the 'debug' configuration
     block (*note line-info: (mailutils)debug statement.).

     The '--no-source-info' can be used to cancel the effect of the
     'line-info yes' configuration statement.

     You do not need this option, unless you are developing or debugging
     'mailfromd'.

'--syntax-check'
     Synonym for '--lint'.

'--trace'
'--no-trace'
     Enable or disable action tracing.  If '--trace' is given,
     'mailfromd' will log all executed actions.  *Note Logging and
     Debugging::.

'--trace-program[=STRING]'
     Enable program instruction tracing.  With this option 'mailfromd'
     will log execution of every instruction in the compiled filter
     program.  The optional arguments allows to specify a
     comma-separated list of source code modules for which the tracing
     is to be enabled, for example '--trace-program=bi_io,bi_db' enables
     tracing for functions from modules 'bi_io.c' and 'bi_db.c' (notice,
     that you need not give file suffixes in STRING).

     This option is useful for debugging 'mailfromd', but is not advised
     to use otherwise, since it is very time-costly.

'-X'
'--transcript'
'--no-transcript'
     Enable or disable transcript of the SMTP sessions to the log
     channel.  *Note Logging and Debugging::.

'--syslog'
     Selects default syslog mechanism for diagnostic output.

'--stderr'
     Directs all logging to standard output.  Similar to
     '--logger=stderr'.

'--xref'
     Same as '--dump-xref'.  *Note Logging and Debugging::.


File: mailfromd.info,  Node: Informational Options,  Prev: Logging and Debugging Options,  Up: options

8.1.6 Informational Options
---------------------------

'-?'
'--help'
     Give a short help summary.

'--usage'
     Give a short usage message.

'-V'
'--version'
     Print program version.


File: mailfromd.info,  Node: Starting and Stopping,  Prev: options,  Up: Invocation

8.2 Starting and Stopping
=========================

Right after startup, when 'mailfromd' has done the operations that
require root privileges, it switches to the privileges of the user it is
configured to run as (*note default user privileges::) or the one given
in its configuration file (*note user: conf-priv.).  During this process
it will drop all supplementary groups and switch to the principal group
of that user.

   Such limited privileges of the daemon can cause difficulties if your
filter script needs to access some files (e.g. 'Sendmail' databases)
that are not accessible to that user and group.  For example, the
following fragment using 'dbmap' function:

     if dbmap("/etc/mail/aliases.db", $f, 1)
       ...
     fi

will normally fail, because '/etc/mail/aliases.db' is readable only to
the root and members of the group 'smmsp'.

   In such situations you need to instruct 'mailfromd' to retain the
privileges of one or several supplementary groups when switching to the
user privileges.  This is done using 'group' statement in the
'mailfromd' configuration file (*note group: conf-priv.).  In example
above, you need to use the following settings:

     group smmsp;

(The same effect can be achieved with '--group' command line option:
'mailfromd --group=smmsp').

   To stop a running instance of 'mailfromd' use one of the following
signals: 'SIGQUIT', 'SIGTERM', 'SIGINT'.  All three signals have the
same effect: the program cancels handling any pending requests,
uninitializes the communication socket (if it is a UNIX socket, the
program unlinks it) and exits.

   To restart the running 'mailfromd' instance, send it 'SIGHUP'.  For
restart to be possible, two conditions must be met: 'mailfromd' must be
invoked with the full file name, and the configuration file name must be
full as well.  If either of them is not met, 'mailfromd' displays a
similar warning message:

     warning: script file is given without full file name
     warning: restart (SIGHUP) will not work

or:

     warning: mailfromd started without full file name
     warning: restart (SIGHUP) will not work

   The reaction of 'mailfromd' on 'SIGHUP' in this case is the same as
on the three signals described previously, i.e.  cleanup and exit
immediately.

   The PID of the master instance of 'mailfromd' is kept on the
"pidfile", which is named 'mailfromd.pid' and is located in the program
"state directory".  Assuming the default location of the latter, the
following command will stop the running instance of the daemon:

     kill -TERM `head -n1 /usr/local/var/mailfromd/mailfromd.pid`

   The default pidfile location is shown in the output of 'mailfromd
--show-defaults' (*note Databases::), and can be changed at run time
using 'pidfile' statement (*note pidfile: conf-base.).

   To facilitate the use of 'mailfromd', it is shipped with a shell
script that can be used to launch it on system startup and shut it down
when the system goes down.  The script, called 'rc.mailfromd', is
located in the directory '/etc' of the distribution.  It takes a single
argument, specifying the action that should be taken:

start
     Start the program.

stop
     Shut down the program

reload
     Reload the program, by sending it 'SIGHUP' signal.

restart
     Shut down the program and start it again.

status
     Display program status.  It displays the PID of the master process
     and its command line, for example:

          $ /etc/rc.d/rc.mailfromd status
          mailformd appears to be running at 26030
          26030 /usr/local/sbin/mailfromd --group smmsp

     If the second line is not displayed, this most probably mean that
     there is a 'stale' pidfile, i.e.  the one left though the program
     is not running.

     An empty 'rc.mailfromd status' output means that 'mailfromd' is not
     running.

configtest [FILE]
     Check the script file syntax, report any errors found and exit.  If
     FILE is given it is checked instead of the default one.

macros [-c] [FILE]
     Parse the script file (or FILE, if it is given, extract the names
     of Sendmail macros it uses and generate corresponding export
     statements usable in the Sendmail configuration file.  By default,
     'mc' statements are generated.  If '-c' ('--cf') is given, the
     statements for 'sendmail.cf' are output.  See the next chapter for
     the detailed description of this mode.

   You can pass any additional arguments to 'mailfromd' by editing
'ARGS' variable near line 22.

   The script is not installed by default.  You will have to copy it to
the directory where your system start-up scripts reside and ensure it is
called during the system startup and shut down.  The exact instructions
on how to do so depend on the operating system you use and are beyond
the scope of this manual.


File: mailfromd.info,  Node: MTA Configuration,  Next: calloutd,  Prev: Invocation,  Up: Top

9 Using 'mailfromd' with Various MTAs
*************************************

The following sections describe how to configure various Milter-capable
MTAs to work with 'mailfromd'.

* Menu:

* Sendmail::
* MeTA1::
* Postfix::


File: mailfromd.info,  Node: Sendmail,  Next: MeTA1,  Up: MTA Configuration

9.1 Using 'mailfromd' with Sendmail.
====================================

This chapter assumes you are familiar with Sendmail configuration in
general and with Milter configuration directives in particular.  It
concentrates only on issues, specific for 'mailfromd'.

   To prepare 'Sendmail' to communicate with 'mailfromd' you need first
to set up the "milter port".  This is done with 'INPUT_MAIL_FILTER'
statement in your 'Sendmail' file:

     INPUT_MAIL_FILTER(`mailfrom', `S=unix:/usr/local/var/mailfromd/mailfrom')

   Make sure that the value of 'S' matches the value of 'listen'
statement in your 'mailfromd.conf' file (*note listen: conf-milter.).
Notice, however, that they may not be literally the same, because
'listen' allows to specify socket address in various formats, whereas
Sendmail's 'S' accepts only milter format.

   If you prefer to fiddle directly with 'sendmail.cf' file, use this
statement instead:

     Xmailfrom, S=unix:/usr/local/var/mailfromd/mailfrom

   If you are using Sendmail version 8.14.0 or newer, you may skip to
the end of this section.  These versions implement newer Milter protocol
that enables 'mailfromd' to negotiate with the MTA the macros it needs
for each state.

   Older versions of Sendmail do not offer this feature.  For Sendmail
versions prior to 8.14.0, you need to manually configure 'Sendmail' to
export macros you need in your 'mailfromd.mf' file.  The simplest way to
do so is using 'rc.mailfromd' script, introduced in the previous
chapter.  Run it with 'macros' command line argument and copy its output
to your 'sendmail.mc' configuration file:

     $ rc.mailfromd macros

   If you prefer to work with 'sendmail.cf' directly, use '-c' ('--cf')
command line option:

     $ rc.mailfromd macros -c

   Finally, if you use other mailfromd script file than that already
installed (for example, you are preparing a new configuration while the
old one is still being used in production environment), give its name in
the command line:

     $ rc.mailfromd macros newscript.mf
     # or:
     $ rc.mailfromd macros -c newscript.mf

   If you use this method, you can skip the rest of this chapter.
However, if you are a daring sort of person and prefer to do everything
manually, follow the instructions below.

   First of all you need to build a list of macros used by handlers in
your 'mailfromd.mf' file.  You can obtain it running 'mailfromd
--dump-macros'.  This will display all macros used in your handlers,
grouped by handler name, for example:

     envfrom i, f, {client_addr}
     envrcpt f, {client_addr}, {rcpt_addr}

   Now, modify 'confMILTER_MACROS_HANDLER' macros in your 'mc' file.
Here, HANDLER means the uppercase name of the 'mailfromd' handler you
want to export macros to, i.e.  the first word on each line of the above
'mailfromd --dump-macros' output.  _Notice,_ that in addition to these
macros, you should also export the macro 'i' for the very first handler
('rc.mailfromd macros' takes care of it automatically, but you preferred
to do everything yourself...)  It is necessary in order for 'mailfromd'
to include 'Message-ID' in its log messages (*note Message-ID::).

   For example, given the above macros listing, which corresponds to our
sample configuration (*note Filter Script Example::), the 'sendmail.mc'
snippet will contain:

     define(`confMILTER_MACROS_ENVFROM',dnl
     confMILTER_MACROS_ENVFROM `, i, f, {client_addr}')
     define(`confMILTER_MACROS_ENVRCPT',dnl
     confMILTER_MACROS_ENVRCPT `, f, {client_addr}, {rcpt_addr}')

   Special attention should be paid to 's' macro ('HELO' domain name).
In 'Sendmail' versions up to 8.13.7 (at least) it is available only to
'helo' handler.  If you wish to make it available elsewhere you will
need to use the method described in *note HELO Domain::

   Now, if you are a _really_ daring person and prefer to do everything
manually _and_ to hack your 'sendmail.cf' file directly, you certainly
don't need any advices.  Nonetheless, here's how the two statements
above _could_ look in this case:

     O Milter.macros.envfrom=i, {auth_type}, {auth_authen}, \
        {auth_ssf}, {auth_author}, {mail_mailer}, {mail_host}, \
        {mail_addr} ,{mail_addr}, {client_addr}, f
     O Milter.macros.envrcpt={rcpt_mailer}, {rcpt_host}, \
        {rcpt_addr} ,i, f, {client_addr}


File: mailfromd.info,  Node: MeTA1,  Next: Postfix,  Prev: Sendmail,  Up: MTA Configuration

9.2 Using 'mailfromd' with MeTA1.
=================================

MeTA1 (<http://www.meta1.org>) is an MTA of next generation which is
designed to provide the following main features:

   * Security
   * Reliability
   * Efficiency
   * Configurability
   * Extendibility

   Instead of using Sendmail-compatible Milter protocol, it implements a
new protocol, called "policy milter", therefore an additional program is
required to communicate with 'mailfromd'.  This program is a
"Pmilter-Milter multiplexer" 'pmult', which is part of the 'Mailfromd'
distribution.  *Note pmult::, for a detailed description of its
configuration.

   The configuration of 'Meta1--Mailfromf' interaction can be subdivided
into three tasks.

  1. Configure 'mailfromd'

     This was already covered in previous chapters.  No special
     'MeTA1'-dependent configuration is needed.

  2. Configure 'pmult' to communicate with 'mailfromd'

     This is described in detail in *note pmult::.

  3. Set up MeTA1 to communicate with 'pmult'

     The MeTA1 configuration file is located in '/etc/meta1/meta1.conf'.
     Configure the 'smtps' component, by adding the following section:

          policy_milter {
              socket {
                  type = TYPE;
                  address = ADDR;
                  [path = PATH;]
                  [port = PORT-NO;]
              };
              [timeout = INTERVAL;]
              [flags = { FLAG };]
          };

     Statements in square brackets are optional.  The meaning of each
     instruction is as follows:

     'type = TYPE'
          Set the type of the socket to communicate with 'pmult'.
          Allowed values for TYPE are:

          inet
               Use INET socket.  The socket address and port number are
               set using the 'address' and 'port' statements (see
               below).

          unix
               Use UNIX socket.  The socket path is given by the 'path'
               statement (see below).

          Notice, that depending on the 'type' setting you have to set
          up either 'address'/'port' or 'path', but not both.

     'address = ADDR'
          Configure the socket address for 'type = inet'.  ADDR is the
          IP address on which 'pmult' is listening (*note listen
          statement: pmult-conf.).

     'port = PORT-NO'
          Port number 'pmult' is listening on (*note listen statement:
          pmult-conf.).

     'path = SOCKET-FILE'
          Full pathname of the socket file, if 'type = unix'.

     'timeout = INTERVAL'
          Sets the maximum amount of time to wait for a reply from
          'pmult'.

          The behavior of 'smtps' in case of time out depends on the
          'flags' settings:

     'flags = { FLAG }'

          FLAG is one of the following:

          abort
               If 'pmult' does not respond, abort the current SMTP
               session with a '421' error.

          accept_but_reconnect
               If 'pmult' does not respond, continue the current session
               but try to reconnect for the next session.

   For example, if the 'pmult' configuration has:

     listen inet://127.0.0.1:3333;

then the corresponding part in '/etc/meta1/meta1.conf' will be

     smtps {
         policy_milter {
             socket {
                 type = inet;
                 address = 127.0.0.1;
                 port = 3333;
             };
             ...
         };
         ...
     };

   Similarly, if the 'pmult' configuration has:

     listen unix:///var/spool/meta1/pmult/socket;

then the '/etc/meta1/meta1.conf' should have:

     smtps {
         policy_milter {
             socket {
                 type = unix;
                 path = /var/spool/meta1/pmult/socket;
             };
             ...
         };
         ...
     };


File: mailfromd.info,  Node: Postfix,  Prev: MeTA1,  Up: MTA Configuration

9.3 Using 'mailfromd' with Postfix
==================================

To configure 'postfix' to work with your filter, you need to inform it
about the socket your filter is listening on.  The 'smtpd_milters' (or
'non_smtpd_milters') statement in '/etc/postfix/main.cf' serves this
purpose.  If the filter is to handle mail that arrives via SMTP, use
'smtpd_milters'.  If it is to handle mail submitted locally to the
queue, use 'non_smtpd_milters'.  In both cases, the value is a
whitespace-separated list of socket addresses.  Note, that Postfix
syntax for socket addresses differs from that used by Sendmail and
mailfromd.  The differences are summarized in the following table:

Sendmail                 Mailfromd                Postfix
---------------------------------------------------------------------------
inet:PORT@HOST           inet://HOST:PORT         inet:HOST:PORT
unix:FILE                unix://FILE              unix:FILE

Table 9.1: Socket addresses in various formats

   For example, if your 'mailfromd' listens on 'inet://127.0.0.1:4111',
add the following to '/etc/postfix/main.cf':

     smtpd_milters = inet:127.0.0.1:4111

   'Mailfromd' uses Milter protocol version 6.  Postfix, starting from
version 2.6 uses the same version.  Older versions of Postfix use Milter
protocol 2 by default.  Normally, it should not be a problem, as
'mailfromd' tries to detect what version the server is speaking.  If,
however, it fails to select the proper version, you will have to
instruct Postfix what version to use.  To do so, add the following
statement to '/etc/postfix/main.cf':

     milter_protocol = 6

   The way Postfix handles macros differs from that of Sendmail.
Postfix emulates a limited subset of Sendmail macros, and not all of
them are are available when you would expect them to.  In particular,
the 'i' macro is not available before the 'DATA' stage, which brings two
consequences.  First, 'mailfromd' log messages will not include message
ID until the 'DATA' stage is reached.  Secondly, you cannot use 'i' in
handlers 'connect', 'helo', 'envfrom' and 'envrcpt',

   If you wish to tailor Postfix defaults to export the actual macros
used by your filter, run 'mailfromd --dump-macros' and filter its output
through the 'postfix-macros.sed' filter, which is installed to the
'PREFIX/share/mailfromd' directory, e.g.:

     $ mailfromd --dump-macros | \
       sed -f /usr/share/mailfromd/postfix-macros.sed
     milter_helo_macros = {s}
     milter_mail_macros = {client_addr} {s} {f}
     milter_rcpt_macros = {rcpt_addr} {f} {client_addr}
     milter_end_of_data_macros = {i}

   Cut and paste its output to your '/etc/postfix/main.cf'.

   For more details regarding Postfix interaction with Milter and
available Postfix configuration options, see Postfix before-queue Milter
support (http://www.postfix.org/MILTER_README.html).


File: mailfromd.info,  Node: calloutd,  Next: mfdbtool,  Prev: MTA Configuration,  Up: Top

10 'calloutd'
*************

The callout verification is usually performed by a special instance of
'mailfromd' (*note callout server::).  However, it is also possible to
set up a dedicated callout server on a separate machine.  You can choose
to do so, for instance, in order to reduce the load on the server
running 'mailfromd'.

   This stand-alone callout facility is provided by the 'calloutd'
daemon.

* Menu:

* config-calloutd::     Calloutd Configuration.
* invocation-calloutd:: Calloutd Command-Line Options.
* protocol-calloutd::   The Callout Protocol.


File: mailfromd.info,  Node: config-calloutd,  Next: invocation-calloutd,  Up: calloutd

10.1 Calloutd Configuration
===========================

Main configuration file '/etc/mailfromd.conf' is used (*note Mailfromd
Configuration::).  The configuration statements are basically the same
as for 'mailfromd'.

   The address to listen on is defined in the 'server' statement.
Basically, it is the only statement the configuration file is required
to have.  The minimal configuration can look like:

     program calloutd {
       server {
         listen inet://198.51.100.1:3535;
       }
     }

   To instruct the 'mailfromd' daemon to use this server, the following
statement should be added to the '/etc/mailfromd.conf' file:

     program mailfromd {
       callout-url inet://198.51.100.1:3535;
     }

   The 'server' statement differs a little from the similar statement
for 'mailfromd'.  This and another 'calloutd'-specific statements are
described in detail in the subsections that follow.  The rest of
statements is shared with 'mailfromd'.  The following table lists all
supported configuration statements along with cross-references to the
correspondent descriptions:

Statement              Reference
-------------------------------------------------------------------
'acl'                  *Note Mailutils Configuration File: (mailutils)acl statement.
'auth'                 *Note Mailutils Configuration File: (mailutils)auth statement.
'database'             *Note conf-database::.
'database-mode'        *Note database-mode: conf-database.
'database-type'        *Note database-type: conf-database.
'debug' (section)      *Note Mailutils Configuration File: (mailutils)debug statement.
'debug'                *Note conf-calloutd-log::.
'ehlo-domain'          *Note ehlo-domain: conf-callout.
'enable-vrfy'          *Note enable-vrfy: conf-callout.
'group'                *Note group: conf-priv.
'include'              *Note Mailutils Configuration File: (mailutils)include.
'io-timeout'           *Note io-timeout: conf-timeout.
'locking'              *Note Mailutils Configuration File: (mailutils)locking statement.
'lock-retry-count'     *Note lock-retry-count: conf-database.
'lock-retry-timeout'   *Note lock-retry-timeout: conf-database.
'logger'               *Note conf-calloutd-log::.
'logging'              *Note Mailutils Configuration File: (mailutils)logging statement.
'mailer'               *Note Mailutils Configuration File: (mailutils)mailer statement.
'mail-from-address'    *Note mail-from-address: conf-callout.
'pidfile'              *Note pidfile: conf-calloutd-setup.
'server'               *Note conf-calloutd-server::.
'source-ip'            *Note source-ip: conf-calloutd-setup.
'smtp-timeout'         *Note conf-timeout::.
'state-directory'      *Note state-directory: conf-calloutd-setup.
'transcript'           *Note conf-calloutd-log::,
'user'                 *Note user: conf-priv.

* Menu:

* conf-calloutd-setup:: 'calloutd' General Setup.
* conf-calloutd-server:: The 'server' Statement.
* conf-calloutd-log:: 'calloutd' Logging.


File: mailfromd.info,  Node: conf-calloutd-setup,  Next: conf-calloutd-server,  Up: config-calloutd

10.1.1 'calloutd' General Setup
-------------------------------

 -- Calloutd Conf: source-ip IP
     Sets source IP address for TCP connections.

 -- Calloutd Conf: pidfile filename
     Defines the name of the file to store PID value in.

 -- Calloutd Conf: state-directory dir
     Sets the name of the program state directory.  *Note statedir::.


File: mailfromd.info,  Node: conf-calloutd-server,  Next: conf-calloutd-log,  Prev: conf-calloutd-setup,  Up: config-calloutd

10.1.2 The 'server' statement
-----------------------------

The 'server' statement configures how 'calloutd' will communicate with
the client 'mailfromd' server.

     server {
       id NAME;
       listen URL;
       backlog NUM;
       max-instances NUM;
       single-process BOOL;
       reuseaddr BOOL;
       default BOOL;
       callout URL;
       acl { ... }
     }

 -- Calloutd Conf: server
     Define a server.  Optional label may follow the 'server' keyword.
     The label is ignored.

     The substatements in the 'server' block provide parameters for
     configuring this server.

 -- server: id name
     Assign an identifier to this server.  This identifier is used as a
     suffix to syslog tag (*note syslog tag::) in messages related to
     this server.  For example, if a server block had the following
     statement in it:

          id main;

     then all messages related to this server will be marked with tag
     'calloutd#main'.

     The part before the '#' is set using the 'tag' statement in
     'logging' block (*note Mailutils Configuration File:
     (mailutils)Logging Statement.).

 -- server: listen url
     Listen for connections on the given URL.  *Note milter port
     specification::, for a description of allowed URL formats.

     Example:

          listen inet://10.10.10.1:3331;

 -- server: backlog NUM
     Configures the size of the queue of pending connections.  Default
     value is 8.

 -- server: max-instances number
     Sets the maximum number of instances allowed for this server.

 -- server: single-process bool
     When set to 'yes', this server will run in "single-process" mode,
     i.e.  it will not fork sub-processes to serve requests.  This
     option is meant exclusively to assist in debugging 'calloutd'.
     Don't use it for anything else but for debugging!

 -- server: reuseaddr bool
     When set to 'yes', 'calloutd' will attempt to reuse existing socket
     addresses.  This is the default behavior.

 -- server: acl STATEMENTS
     Defines access control list for this server.  *Note Mailutils
     Configuration File: (mailutils)ACL Statement, for a detailed
     discussion.

     If the global ACL is defined as well, an incoming connection is
     checked against both lists: first the per-server ACL, then the
     global one.  The connection will be permitted only if it passes
     both checks.


File: mailfromd.info,  Node: conf-calloutd-log,  Prev: conf-calloutd-server,  Up: config-calloutd

10.1.3 'calloutd' logging
-------------------------

 -- Calloutd Conf: logger mech
     Set default logger mechanism.  Allowed values for MECH are:

     stderr
          Log everything to the standard error.

     syslog
          Log to syslog.

     syslog:async
          Log to syslog using the asynchronous syslog implementation.

     *Note Logging and Debugging::, for a detailed discussion.  See also
     *note Using non-blocking syslog: syslog-async, for information on
     how to set default syslog implementation at compile time.

 -- Calloutd Conf: debug spec
     Set 'mailfromd' debug verbosity level.  The SPEC must be a valid
     debugging level specification (*note debugging level
     specification::).

 -- Calloutd Conf: transcript BOOL
     If the boolean value BOOL is 'true', enables the transcript of
     call-out SMTP sessions.


File: mailfromd.info,  Node: invocation-calloutd,  Next: protocol-calloutd,  Prev: config-calloutd,  Up: calloutd

10.2 Calloutd Command-Line Options
==================================

The 'calloutd' invocation syntax is:

       calloutd [OPTION...]

   The following options are available:

Server configuration modifiers
------------------------------

'--foreground'
     Stay in foreground.  When given this option, 'calloutd' will not
     disconnect itself from the controlling terminal and will run in the
     foreground.

'-g NAME'
'--group=NAME'

     Retain the group NAME when switching to user privileges.  *Note
     Starting and Stopping::.

'--pidfile=FILE'
     Set pidfile name.  Overrides the 'pidfile' configuration statement,
     which you are advised to use instead (*note pidfile: conf-base.).

'--resolv-conf-file=FILE'
     Read resolver settings from FILE, instead of the default
     '/etc/resolv.conf'.

'-S IP'
'--source-ip=IP'
     Set source address for TCP connections.  Overrides the 'source-ip'
     configuration statement, which you are advised to use instead
     (*note source-ip: conf-base.).

'--single-process'
     Do not fork sub-processes to serve requests.  This option is meant
     to assist in debugging 'calloutd'.  Don't use it for anything else
     but for debugging, as it terribly degrades performance!

'--state-directory=DIR'
     Set new program state directory.  *Note Local state directory:
     statedir, for the description of this directory and its purposes.

'-u NAME'
'--user NAME'
     Switch to this user's privileges after startup.  Overrides the
     'user' configuration file statement, which you are advised to use
     instead (*note user: conf-priv.).  Default user is 'mail'.

Logging and debugging options
-----------------------------

'-d STRING'
'--debug=STRING'
     Set debugging level.  *Note Logging and Debugging::.

'--log-facility=FACILITY'
     Output logs to syslog FACILITY.

'--log-tag=STRING'
     Tag syslog entries with the given STRING, instead of the program
     name.

'--logger=MECH'
     Set logger mechanism (MECH is one of 'stderr', 'syslog',
     'syslog:async').  *Note Logging and Debugging::.

'--syslog'
     Selects default syslog mechanism for diagnostic output.

'--stderr'
     Directs all logging to standard output.  Similar to
     '--logger=stderr'.

'-S IP'
'--source-ip=IP'
     Set source address for TCP connections.  Overrides the 'source-ip'
     configuration statement, which you are advised to use instead
     (*note source-ip: conf-base.).

'--debug-level=LEVEL'
     Set Mailutils debugging level.  See
     <http://mailutils.org/wiki/Debug_level>, for a detailed discussion
     of LEVEL argument.

'--source-info'
'--no-source-info'
     Include C source information in debugging messages.  This is
     similar to setting 'line-info yes' in the 'debug' configuration
     block (*note line-info: (mailutils)debug statement.).

     The '--no-source-info' can be used to cancel the effect of the
     'line-info yes' configuration statement.

     You do not need this option, unless you are developing or debugging
     'calloutd'.

'-X'
'--transcript'
'--no-transcript'
     Enable or disable transcript of the SMTP sessions to the log
     channel.  *Note Logging and Debugging::.

Configuration file control
--------------------------

'--config-file=FILE'
     Load this configuration file.

'--config-lint'
     Check syntax of configuration files and exit.  Exit code is 0 if
     the file or files are OK, and 78 otherwise.

'--config-verbose'
     Verbosely log parsing of the configuration files.

'--no-site-config'
'--no-config'
     Don't load site-wide configuration file.

'--set=PARAM=VALUE'
     Set configuration parameter

Informational options
---------------------

'--config-help'
     Show configuration file summary.

'--show-config-options'
     Show compilation options.

'-?'
'--help'
     Give a short help list.

'--usage'
     Give a short usage message.

'-V'
'--version'
     Print program version


File: mailfromd.info,  Node: protocol-calloutd,  Prev: invocation-calloutd,  Up: calloutd

10.3 The Callout Protocol
=========================

This section describes the protocol used to communicate with the
'calloutd' server.

   The protocol works over stream-oriented TCP/IP transport.  Either
UNIX or IPv4 socket can be used.  Commands and responses are terminated
by a single CR LF pair.  Each command occupies exactly one line.  If the
server succeeded in executing the command, it replies with a line
starting with the word 'OK'.  Depending on the command, this keyword may
be followed by a single space character and additional information.
More information can be returned in "unsolicited replies" before the
'OK' line.  Each unsolicited reply line starts with and asterisk
followed by a single horizontal space character.

   On error, the server replies with 'NO' followed by a horizontal space
character and human-readable description of the problem.

   The valid commands are discussed below.  In examples illustrating the
commands, the lines sent by the client are prefixed with 'C:', and lines
sent by the server are prefixed with 'S:'.

 -- Command: vrfy EMAIL [OPTION ARG]
     Adds EMAIL to the queue of email addresses to be verified.
     Available OPTIONs are:

     'mode KW'
          Sets verification mode for this email address.  Available
          modes are:

          mxfirst
          default
               The default mode.

               If the 'host' option is also given, its argument is taken
               as the domain name.  Otherwise, domain part of EMAIL is
               used.

               The verification goes as follows.  First, determine MX
               servers for that domain.  Query each of them in order of
               increasing priority.  First of them that replies
               determines the result of the test.

               If no MX servers are defined for that domain, look for
               its 'A' record.  If available, run SMTP probe on that IP.

          mxonly
               Query MX servers for the domain specified with the 'host'
               option.

          hostonly
               Query the server whose name or IP address is supplied
               with the 'host' option.

          hostfirst
               The reverse of 'mxfirst': first query the host, then the
               MX servers.  The domain must be specified using the
               'host' option.

     'host NAME'
          Supplies the domain name for 'mxonly' and mode, and host name
          or IP address for 'hostfirst' and 'hostonly' modes.  The use
          of this keyword with any of these modes is mandatory.

     'ehlo STRING'
          Use STRING as the argument to the SMTP 'EHLO' command.

     'mailfrom EMAIL'
          Use EMAIL in the SMTP 'MAIL FROM' command.

     On success, the server replies with 'OK', followed by a
     non-negative session ID for that email:

          C: VRFY gray@example.org
          S: OK 0000000001

 -- Command: get ARG [ARG]
     Query value of internal callout parameters.  Valid values for ARG
     are:

     ehlo
          Return the string used as argument to the SMTP 'EHLO' command.

     mailfromd
          Return the email address that is used in the SMTP 'MAIL FROM'
          command.

     On success, the server returns the requested value (if found) in an
     unsolicited reply:

          C: GET ehlo timeout
          S: * ehlo=example.net
          S: OK

 -- Command: sid STRING
     Sets STRING as session identifier for that session.  Example:

          C: SID deadbeef
          S: OK

 -- Command: timeout CONNECT INITIAL HELO MAIL RCPT RSET QUIT
     Sets timeouts for various stages of SMTP session.  On success, 'OK'
     is returned.

          C: timeout 300 300 300 600 300 300 120
          S: OK timeouts set

 -- Command: run
     Runs callout session for emails registered with the 'vrfy' command.
     On success, results of the check are returned after the 'OK'
     keyword in a whitespace-separated list of 'ID=RESULT' pairs.  In
     each pair, ID is its identifier as returned in the reply to the
     'VRFY' command and RESULT is one of the following result strings:
     'success', 'not_found', 'failure', 'temp_failure', 'timeout'.

     Additional information about each callout session is returned in
     unsolicited replies.  Each such reply is prefixed with the email
     identifier and callout stage name.  Stage names are:

     'INIT REMOTE_NAME'
          The 'calloutd' server is establishing communication with the
          remote SMTP server REMOTE_NAME.

     'GRTNG LINE'
          'calloutd' received initial response from the remote server.
          LINE is the first line of the reply.

     'HELO LINE'
          'calloutd' received response to the 'EHLO' (or 'HELO')
          command.  In case of multiline response, LINE is the first
          line.

     'SENT COMMAND'
          The SMTP command COMMAND has been sent to the remote server.

     'RECV LINE'
          The remote server returned LINE in response.  In case of
          multiline response, LINE is the first line.

     Example of verification session:

          C: RUN
          S: * 0000000000 INIT mx.example.org
          S: * 0000000000 GRTNG 220 mx.example.org ESMTP Ready
          S: * 0000000000 HELO 250-mx.example.org Hello tester
          S: * 0000000000 SENT RCPT TO:<gray@example.org>
          S: * 0000000000 RECV 250 Accepted
          S: * 0000000001 INIT foo.example.net
          S: * 0000000001 GRTNG 220 foo ESMTP server ready
          S: * 0000000001 HELO 250-foo.example.net Hello
          S: * 0000000001 SENT RCPT TO:<gray@example.net>
          S: * 0000000001 RECV 450 4.7.0 You are greylisted for 3600 seconds
          OK 0000000000=success 0000000001=temp_failure

 -- Command: drop SERIAL
     Drop the email with the given SERIAL number from the verification
     queue.  Example:

          C: DROP 0000000002
          S: OK

 -- Command: quit
     Finishes the current session and disconnects from the callout
     server.

          C: QUIT
          S: OK bye


File: mailfromd.info,  Node: mfdbtool,  Next: mtasim,  Prev: calloutd,  Up: Top

11 'mfdbtool'
*************

The 'mfdbtool' utility manages 'mailfromd' databases.

* Menu:

* Invoking mfdbtool::
* Configuring mfdbtool::


File: mailfromd.info,  Node: Invoking mfdbtool,  Next: Configuring mfdbtool,  Up: mfdbtool

11.1 Invoking 'mfdbtool'
========================

The following options request the operation to be performed on the
database.  Exactly one of them must be specified.  Each of them implied
the '--stderr' option (*note --stderr::).

'--list'
     List the database.  By default, 'cache' database is assumed.  To
     list another database, use '--format' option (*note --format::).

     *Note Basic Database Operations::.

'--delete'
     Delete given entries from the database (*note deleting from
     databases::).  By default, 'cache' database is assumed.  To specify
     another database, use '--format' option (*note --format::).

     *Note Basic Database Operations::.

'--expire'
     Delete all expired entries from the database (*note Database
     Maintenance::).  By default, 'cache' database is assumed.  To
     specify another database, use '--format' option (*note --format::).
     Full database name can be given in the command line (see '--file'
     option below), if it differs from the one specified in the script
     file.

     Use with the option '--all' (*note --all::) to expire all
     databases.

     *Note Database Maintenance::.

'--compact'
     Compact database (*note compaction::).  By default, 'cache'
     database is compacted.  To specify another database, use '--format'
     option (*note --format::).  Full database name can be given in the
     command line (see '--file' option below), if it differs from the
     one specified in the script file.

     Use with the option '--all' (*note --all::) to compact all
     databases.

     *Note compaction::.

   The following options modify the behavior of 'mfdbtool':

'--all'
     When used with '--compact' or '--expire' option, applies the action
     to all available databases.  *Note compact cronjob::.

'-d STRING'
'--debug=STRING'
     Sets debugging level.  The STRING argument must be a valid
     mailfromd debug level specification, as described in *note
     debugging level specification::.

'-e INTERVAL'
'--expire-interval=INTERVAL'
     Set expiration intervals for all databases to the specified
     interval.  *Note time interval specification::, for a description
     of INTERVAL format.  The option overrides the 'expire-interval'
     configuration statement (*note expire-interval-conf::), which you
     are advised to use instead.

'-f FILENAME'
'--file=FILENAME'
     Set the name of the database to operate upon (for '--compact',
     '--delete', '--expire', and '--list' options).  Useful if, for some
     reason, you need to operate on a database whose file name does not
     match the one 'mfdbtool' is configured to use.

'-H DBFORMAT'
'--format=DBFORMAT'
     Use database of the given format, instead of the default 'cache'.
     *Note Basic Database Operations::.

'--ignore-failed-reads'
     Ignore records that cannot be retrieved while compacting the
     database.  Without this option, 'mfdbtool' will abort the
     compaction if any such error is encountered.

'--predict=RATE-LIMIT'
     Used with '--list' enables printing of the estimated times of
     sending along with the 'rate' database dump.  Implies '--list
     --format=rate'.  *Note estimated time of sending::.

'--state-directory=DIR'
     Sets program state directory.  *Note Local state directory:
     statedir, for the description of this directory and its purposes.
     This option overrides the 'state-directory' configuration
     statement, described in *note state-directory: conf-base.

'--time-format=FORMAT'
     Set format to be used for timestamps in listings, produced by
     '--list'.  The FORMAT is any valid 'strftime' format string, see
     *note Time and Date Formats::, for a detailed description.  The
     default FORMAT is '%c' (*note %c time format::).  To analyze
     'mfdbtool --list' output using text tools, such as 'awk' or 'grep',
     the following format might be useful: '%s' (*note %s time
     format::).  Another format I find useful is '%Y-%m-%d_%H:%M:%S'.


File: mailfromd.info,  Node: Configuring mfdbtool,  Prev: Invoking mfdbtool,  Up: mfdbtool

11.2 Configuring 'mfdbtool'
===========================

Configuration settings are read from the '/etc/mailfromd.conf' file
(*note Mailfromd Configuration::).  The following statements are
understood:

Statement              Reference
-------------------------------------------------------------------
'database'             *Note conf-database::.
'database-mode'        *Note database-mode: conf-database.
'database-type'        *Note database-type: conf-database.
'debug'                *Note conf-calloutd-log::.
'lock-retry-count'     *Note lock-retry-count: conf-database.
'lock-retry-timeout'   *Note lock-retry-timeout: conf-database.
'state-directory'      *Note state-directory: conf-calloutd-setup.


File: mailfromd.info,  Node: mtasim,  Next: pmult,  Prev: mfdbtool,  Up: Top

12 'mtasim' -- a testing tool
*****************************

The 'mtasim' utility is a MTA simulator for testing 'mailfromd' filter
scripts.  By default it operates in "stdio" mode, similar to that of
'sendmail -bs'.  In this mode it reads SMTP commands from standard input
and sends its responses to the standard output.  There is also another
mode, called "daemon", where 'mtasim' opens a TCP socket and listens on
it much like any MTA does.  In both modes no actual delivery is
performed, the tool only simulates the actions an MTA would do and
responses it would give.

   This tool is derived from the program 'mta', which I wrote for GNU
Anubis test suite.

* Menu:

* interactive mode::
* expect commands::
* traces::
* daemon mode::
* command summary::
* option summary::


File: mailfromd.info,  Node: interactive mode,  Next: expect commands,  Up: mtasim

12.1 'mtasim' interactive mode mode
===================================

If you start 'mtasim' without options, you will see the following:

     220 mtasim (mailfromd 8.14) ready
     (mtasim) _

   The first line is an usual RFC 2821 reply.  The second one is a
prompt, indicating that 'mtasim' is in interactive mode and ready for
input.  The prompt appears only if the package is compiled with GNU
Readline and 'mtasim' determines that its standard input is connected to
the terminal.  This is called "interactive mode" and is intended to save
the human user some typing by offering line editing and history
facilities (*note Command Line Editing: (readline)Command Line
Editing.).  If the package is compiled without GNU Readline, you will
see:

     220 mtasim (mailfromd 8.14) ready
     _

where '_' represents the cursor.  Whatever the mode, 'mtasim' will wait
for further input.

   The input is expected to consist of valid SMTP commands and special
'mtasim' statements.  The utility will act exactly like a RFC
2821-compliant MTA, except that it will not do actual message delivery
or relaying.  Try typing 'HELP' to get the list of supported commands.
You will see something similar to:

     250-mtasim (mailfromd 8.14); supported SMTP commands:
     250- EHLO
     250- HELO
     250- MAIL
     250- RCPT
     250- DATA
     250- HELP
     250- QUIT
     250- HELP
     250  RSET

   You can try a simple SMTP session now:

     220 mtasim (mailfromd 8.14) ready
     (mtasim) ehlo localhost
     250-pleased to meet you
     250 HELP
     (mtasim) mail from: <me@localhost>
     250 Sender OK
     (mtasim) rcpt to: <him@domain>
     250 Recipient OK
     (mtasim) data
     354 Enter mail, end with `.' on a line by itself
     (mtasim) .
     250 Mail accepted for delivery
     (mtasim) quit
     221 Done

   Notice, that 'mtasim' does no domain checking, so such thing as 'rcpt
to: <him@domain>' was eaten without complaints.

   So far so good, but what all this has to do with 'mailfromd'?  Well,
that's what we are going to explain.  To make 'mtasim' consult any
milter, use '--port' ('-X') command line option.  This option takes a
single argument that specifies the milter port to use.  The port can be
given either in the usual Milter format (*Note milter port
specification::, for a short description), or as a full 'sendmail.cf'
style 'X' command, in which case it allows to set timeouts as well:

     $ mtasim --port=inet:999@localhost
     # This is also valid:
     $ mtasim --port='mailfrom, S=inet:999@localhost, F=T, T=C:100m;R:180s'

   If the milter is actually listening on this port, 'mtasim' will
connect to it and you will get the following initial prompt:

     220-mtasim (mailfromd 8.14) ready
     220 Connected to milter inet://localhost:999
     (mtasim)

   Notice, that it makes no difference what implementation is listening
on that port, it may well be some other filter, not necessarily
'mailfromd'.

   However, let's return to 'mailfromd'.  If you do not want to connect
to an existing 'mailfromd' instance, but prefer instead to create a new
one and run your tests with it (a preferred way, if you already have a
stable filter running but wish to test a new script without disturbing
it), use '--port=auto'.  This option instructs 'mtasim' to do the
following:

  1. Create a unique temporary directory in '/tmp' and create a
     communication socket within it.
  2. Spawn a new instance of 'mailfromd'.  The arguments and options for
     that instance may be given in the invocation of 'mtasim' after a
     double-dash marker ('--')
  3. Connect to that filter.

   When 'mtasim' exits, it terminates the subsidiary 'mailfromd' process
and removes the temporary directory it has created.  For example, the
following command will start 'mailfromd -I. -I../mflib test.rc':

     $ mtasim -Xauto -- -I. -I../mflib test.rc
     220-mtasim (mailfromd 8.14) ready
     220 Connected to milter unix:/tmp/mtasim-j6tRLC/socket
     (mtasim)

   The '/tmp/mtasim-j6tRLC' directory and any files within it will exist
as long as 'mtasim' is running and will be removed when you exit from
it.(1)  You can also instruct the subsidiary 'mailfromd' to use this
directory as its state directory (*note statedir::).  This is done by
'--statedir' command line option:

     $ mtasim -Xauto --statedir -- -I. -I../mflib test.rc

(notice that '--statedir' is the 'mtasim' option, therefore it must
appear _before_ '--')

   Special care should be taken when using 'mtasim' from root account,
especially if used with '-Xauto' and '--statedir'.  The 'mailfromd'
utility executed by it will switch to privileges of the user given in
its configuration (*note Starting and Stopping::) and will not be able
to create data in its state directory, because the latter was created
using 'root' as owner.  To help in this case, 'mtasim' understands
'--user' and '--group' command line options, that have the same meaning
as for 'mailfromd'.

   Now, let's try 'HELP' command again:

     250-mtasim (mailfromd 8.14); supported SMTP commands:
     250- EHLO
     250- HELO
     250- MAIL
     250- RCPT
     250- DATA
     250- HELP
     250- QUIT
     250- HELP
     250- RSET
     250-Supported administrative commands:
     250- \Dname=value [name=value...]       Define Sendmail macros
     250- \Ecode                             Expect given SMTP reply code
     250- \L[name] [name...]                 List macros
     250- \Uname [name...]                   Undefine Sendmail macros
     250  \Sfamily hostname address [port]   Define sender socket address

   While the SMTP commands do not need any clarification, some words
about the "administrative commands" are surely in place.  These commands
allow to define, undefine and list arbitrary Sendmail macros.  Each
administrative command consists of a backslash followed by a command
letter.  Just like SMTP ones, administrative commands are
case-insensitive.  If a command takes arguments, the first argument must
follow the command letter without intervening whitespace.  Subsequent
arguments can be delimited by arbitrary amount of whitespace.

   For example, the '\D' command defines Sendmail macros:

     (mtasim) \Dclient_addr=192.168.10.1 f=sergiusz@localhost i=testmsg
     (mtasim)

Notice that 'mailfromd' does not send any response to the command,
except if there was some syntactic error, in which case it will return a
'502' response.

   Now, you can list all available macros:

     (mtasim) \L
     220-client_addr=192.168.10.1
     220-f=sergiusz@localhost
     220 i=testmsg
     (mtasim)

or just some of them:

     (mtasim) \Lclient_addr
     220 client_addr=192.168.10.1
     (mtasim)

   To undefine a macro, use '\U' command:

     (mtasim) \Ui
     (mtasim) \l
     220-client_addr=192.168.10.1
     220 f=sergiusz@localhost
     (mtasim)

   The '\S' command declare sender socket and host name.  These
parameters are passed to the 'connect' handler, if one is declared
(*note connect handler::).  To give you a chance to use this command,
'mtasim' does not invoke 'connect' handler right after connecting to the
milter.  Instead it waits until either the '\S' command or any SMTP
command (except 'HELP') is given.  After calling 'connect' handler the
'\S' is disabled (to reflect it, it also disappears from the 'HELP'
output).

   The '\S' command takes 1 to 4 arguments.  The first argument supplies
the socket family (*note Table 4.3: socket-families.).  Allowed values
are: 'stdio', 'unix', 'inet', 'inet6' or numbers from '0' to '3'.

   The '\S stdio' (or '\S 0') command needs no additional arguments.  It
indicates that the SMTP connection is obtained from the standard input.
It is the default if sender socket is not declared explicitly.

   The command '\S unix' indicates that the connection is accepted from
a UNIX socket.  It requires two more argument.  The first one supplies
sender host name and the second one supplies full path name of the
socket file.  For example:

     \S unix localhost /var/run/smtp.sock

   The commands '\S inet' and '\S inet6' indicate that the connection
came from an 'INET' IPv4 or IPv6 socket, correspondingly(2).  They
require all four arguments to be specified.  The additional arguments
are: host name, IP address, and port number, in that order.  For
example:

     \S inet relay.gnu.org.ua 213.130.31.41 34567

   or

     \S inet6 relay.gnu.org.ua 2001:470:1f0a:1be1::2 34567

   Sender socket address can also be configured from the command line
(*note sender-socket: option summary.).

   Now, let's try a real-life example.  Suppose you wish to test the
greylisting functionality of the filter script described in *note Filter
Script Example::.  To do this, you start 'mtasim':

     $ mtasim -Xauto -- -I. -I../mflib test.rc
     220-mtasim (mailfromd 8.14) ready
     220 Connected to milter unix:/tmp/mtasim-ak3DEc/socket
     (mtasim)

   The script in 'test.rc' needs to know 'client_addr' macro, so you
supply it to 'mtasim':

     (mtasim) \Dclient_addr=10.10.1.13

   Now, you try an SMTP session:

     (mtasim) ehlo yahoo.com
     250-pleased to meet you
     250 HELP
     (mtasim) mail from: <gray@yahoo.com>
     250 Sender OK
     (mtasim) rcpt to: <gray@localhost>
     450 4.7.0 You are greylisted for 300 seconds

   OK, this shows that the greylisting works.  Now quit the session:

     (mtasim) quit
     221 Done

   ---------- Footnotes ----------

   (1) However, this is true only if the program is exited the usual way
(via 'QUIT' or end-of-file).  If it is aborted with a signal like
'SIGINTR', the temporary directory is not removed.

   (2) Depending on how 'mailfromd' is configured, 'inet6' may be not
available.


File: mailfromd.info,  Node: expect commands,  Next: traces,  Prev: interactive mode,  Up: mtasim

12.2 'mtasim' expect commands
=============================

Until now we were using 'mtasim' interactively.  However, it is often
useful in shell scripts, for example the 'mailfromd' test suite is
written in shell and 'mtasim'.  To avoid the necessity to use auxiliary
programs like 'expect' or 'DejaGNU', 'mtasim' contains a built-in expect
feature.  The administrative command '\E' introduces the SMTP code that
the next command is expected to yield.  For example,

     \E250
     rcpt to: <foo@bar.org>

tells 'mtasim' that the response to 'RCPT TO' command must begin with
'250' code.  If it does, 'mtasim' continues execution.  Otherwise, it
prints an error message and terminates with exit code 1.  The error
message it prints looks like:

     Expected 250 but got 470

   The expect code given with the '\E' command may have less than 3
digits.  In this case it specifies the first digits of expected reply.
For example, the command '\E2' matches replies '200', '220', etc.

   This feature can be used to automate your tests.  For example, the
following script tests the greylisting functionality (see the previous
section):

     # Test the greylisting functionality
     #
     \E220
     \Dclient_addr=10.10.1.13
     \E250
     ehlo yahoo.com
     \E250
     mail from: <gray@yahoo.com>
     \E450
     rcpt to: <gray@localhost>
     \E221
     quit

   This example also illustrates the fact that you can use '#'-style
comments in the 'mtasim' input.  Such a script can be used in shell
programs, for example:

     mtasim -Xauto --statedir -- -I. -I../mflib test.rc < scriptfile
     if $? -ne 0; then
       echo "Greylisting test failed"
     fi


File: mailfromd.info,  Node: traces,  Next: daemon mode,  Prev: expect commands,  Up: mtasim

12.3 Trace Files
================

It is possible to log an entire SMTP session to a file.  This is called
"session tracing".  Two options are provided for this purpose:

'--trace-file=FILE'
     Sets the name of the trace file, i.e.  a file to which the session
     transcript will be written.  Both the input commands, and the
     'mtasim' responses are logged.  If the file FILE exists, it will be
     truncated before logging.  This, however, can be changed using the
     following option:

'-a'
'--append'
     If the trace file exists, append new trace data to it.


File: mailfromd.info,  Node: daemon mode,  Next: command summary,  Prev: traces,  Up: mtasim

12.4 Daemon Mode
================

To start 'mtasim' in "daemon" mode, use the '--daemon' (or '-bd')
command line option.  This mode is not quite the same as Sendmail '-bd'
mode.  When started in "daemon" mode, 'mtasim' selects the first
available TCP port to use from the range '1024 -- 65535'.  It prints the
selected port number on the standard output and starts listening on it.
When a connection comes, it serves a _single_ SMTP session and exits
immediately when it is ended.

   This mode is designed for use in shell scripts and automated test
cases.


File: mailfromd.info,  Node: command summary,  Next: option summary,  Prev: daemon mode,  Up: mtasim

12.5 Summary of the 'mtasim' Administrative Commands
====================================================

This section provides a summary of administrative commands available in
'mtasim'.

 -- mtasim command: \D name=value [name=value...]
     Defines Sendmail macro NAME to the given VALUE.  Any number of
     NAME=VALUE pairs can be given as arguments.

     *Note D command::.

 -- mtasim command: \E code
     Instructs 'mtasim' to expect next SMTP command to return given CODE
     (a three-digit decimal number).

     *Note expect commands::.

 -- mtasim command: \L [name...]
     Lists defined macros.  *Note L command::.

 -- mtasim command: \U name [name...]
     Undefines macros given as its arguments.

 -- mtasim command: \S family [hostname address [port]]
     Declares the sender socket parameters.  *Note S command::, for a
     detailed description and examples.

     This command is available only at the initial stage of a 'mtasim'
     session, before the first SMTP command was given.  It is disabled
     if the '--sender-socket' option was given in the command line
     (*note sender-socket: option summary.).  The 'help' output reflects
     whether or not this command is available.

     If neither this command nor the '--sender-socket' option were
     given, 'mtasim' behaves as if given the '\S stdio' command.

     The FAMILY argument supplies the socket family, i.e.  the first
     argument to the 'connect' handler (*note connect handler::).  It
     can have either literal or numeric value, as described in the table
     below:

     Literal            Numeric Meaning
     ------------------------------------------------------------
     stdio              0       Standard input/output (the MTA
                                is run with '-bs' option)
     unix               1       UNIX socket
     inet               2       IPv4 protocol
     inet6              3       IPv6 protocol

     Table 12.1: Socket families

     See also *note Table 4.3: socket-families.

     Depending on the FAMILY, the rest of arguments supply additional
     parameters:

     stdio
          The HOSTNAME argument can be specified.  It defines the first
          argument of the 'connect' handler (*note hostname in connect
          handler::).

     inet
     inet6
          All arguments must be specified.

          argument                      'connect'      meaning
                                        argument
          ---------------------------------------------------------------------------
          hostname                      1              Sender host name
          address                       4              Sender IP address
          port                          3              Sender port number

     unix
          HOSTNAME and ADDRESS must be supplied.  The ADDRESS argument
          must be a full pathname of the UNIX socket.


File: mailfromd.info,  Node: option summary,  Prev: command summary,  Up: mtasim

12.6 'mtasim' command line options
==================================

This section summarizes all available 'mtasim' command line options.

'--append'
'-a'
     Append to the trace file.  *Note traces::.

'--body-chunk=NUMBER'
     Set the body chunk length (bytes) for 'xxfi_body' calls.

'--daemon'
'-bd'
     Run as daemon.  *Note daemon mode::.

'--define=MACRO=VALUE'
'-D MACRO=VALUE'
     Define Sendmail macro MACRO to the given VALUE.  It is similar to
     the '\D' administrative command (*note D command::)

'--gacopyz-log=LEVEL'
     Set desired logging level for 'gacopyz' library (*note Gacopyz::).
     *Note gacopyz-log option::, for a detailed description of LEVEL.
     Notice, that unless this option is used, the '--verbose' ('-v')
     command line option implies '--gacopyz-log=debug'.

'--group=NAME'
'-g NAME'
     When switching to user's privileges as requested by the '--user'
     command line option, retain the additional group NAME.  Any number
     of '--group' options may be given to supply a list of additional
     groups.

'--user=NAME'
'-u NAME'
     Run with this user privileges.  This option and the '--group'
     option have effect only if 'mtasim' was started with root
     privileges.

'--help'
'-?'
     Display a short help summary

'--milter-version=VERSION'
     Force using the given Milter protocol version number.  The VERSION
     argument is either a numeric version (e.g. '2'), or a version
     string in form 'MAJOR.MINOR[.PATCH]', where square brackets
     indicate optional part.  The default is '1.0.0'.  If VERSION is any
     of '2', '3' or '1.0.0', the default protocol capabilities and
     actions for that version are set automatically.  This option is
     intended for development and testing of the Gacopyz library (*note
     Gacopyz::).

'--milter-proto=BITMASK'
     Set Milter protocol capabilities.  See 'gacopyz/gacopyz.h' for the
     meaning of various bits in the BITMASK.  Look for the C macros with
     the prefix 'SMFIP_'.

'--milter-timeout=VALUES'
     Set timeouts for various Milter operations.  VALUES is a
     comma-separated list of assignments 'T=V', where T is a "timeout
     code", indicating which timeout to set, and V is its new value.
     Valid timeout codes are:

     C
          Timeout for connecting to a filter.

     W
     S
          Timeout for sending information from the simulator to a
          filter.

     R
          Timeout for reading reply from the filter.

     E
          Overall timeout between sending end-of-message to filter and
          receiving final acknowledgment.  Indirectly, it configures the
          upper limit on the execution time of the 'eom' handler (*note
          eom handler::).

'--milter-actions=BITMASK'
     Set Milter actions.  See 'gacopyz/gacopyz.h' for the meaning of
     various bits in the BITMASK.  Look for the C macros with the prefix
     'SMFIF_'.

'--no-interactive'
     Not-interactive mode (disable readline).  *Note Command Line
     Editing: (readline)Command Line Editing.

'--port=PORT'
'-X PORT'
     Communicate with given Milter PORT.  *Note mtasim milter port::.

'--prompt=STRING'
     Set readline prompt.  The default prompt string is '(mtasim) '.

'--sender-socket=FAMILY[,HOSTNAME,ADDRESS[,PORT]]'
     Declare sender socket address.  This option has the same effect as
     the 'S command'.  *Note S command::, for a detailed discussion and
     a description of its arguments.

'--statedir'
     When using '-Xauto', use the temporary directory name as
     'mailfromd' state directory (*note statedir mtasim option::).

'--stdio'
'-bs'
     Use the SMTP protocol on standard input and output.  This is the
     default mode for 'mtasim'.  *Note interactive mode::.

'--trace-file=FILE'
     Set name of the trace file.  *Note traces::.

'--usage'
     Display option summary

'--verbose'
'-v'
     Increase verbosity level.  Implies '--gacopyz-log=debug', unless
     that option is used explicitly.

'--version'
'-V'
     Print program version


File: mailfromd.info,  Node: pmult,  Next: Reporting Bugs,  Prev: mtasim,  Up: Top

13 Pmilter multiplexer program.
*******************************

'Pmult' is a "Pmilter-Milter multiplexer", i.e.  a program that acts as
a mediator between the Pmilter server and one or several Milter clients.
Usually, the former is an instance of 'smtps' from MeTA1, and the latter
are running 'mailfromd' instances.  'Pmult' receives Pmilter commands
from the server, translates them into equivalent Milter commands and
passes the translated requests to a preconfigured set of Milter filters.
When the filters reply, the reverse operation is performed: Milter
responses are translated into their Pmilter equivalents and are sent
back to the server.

                                                 +-----------------+
                                          +----->| Milter Client 1 |
                                          |      +-----------------+
                                          |
        +-----------+       +---------+   |      +-----------------+
        |   MeTA1   |<=====>|  Pmult  |<--+----->| Milter Client 1 |
        +-----------+       +---------+   |      +-----------------+
                                          |
                                          +--------->    //
                                          |
                                          |      +-----------------+
                                          +----->| Milter Client N |
                                                 +-----------------+

   Due to the specifics nature of the threaded MeTA1 libraries, 'pmult'
does not detach from the controlling terminal (i.e.  does not become a
daemon).  To run it as a background process, we recommend to use 'pies'
daemon.  'Pies' is a powerful utility that allows you to launch several
foreground-designed programs in the background and control their
execution.  *Note Pies Manual: (pies)Top, for a detailed description of
the program.  For a practical advice on how to use it with 'pmult', see
*note Using Pies to Run Pmult: (pies)Simple Pies.  For a description on
how to start both 'pmult' and MeTA1 from the same 'pies' configuration
file, see *note Using Pies to Run Pmult and MeTA1: (pies)Hairy Pies.

* Menu:

* pmult configuration::
* pmult example::
* pmult invocation::


File: mailfromd.info,  Node: pmult configuration,  Next: pmult example,  Up: pmult

13.1 Pmult Configuration
========================

'Pmult' reads its configuration from the main configuration file
'/etc/mailfromd.conf'.  Unless it is the only component of the
'Mailfromd' package that is being run, its configuration should be
explicitly marked as such by using either 'program' or 'include'
statement, as described in *note Mailfromd Configuration::.

   The following standard Mailutils statements are understood:

Statement              Reference
-------------------------------------------------------------------
debug                  *Note Mailutils Configuration File: (mailutils)debug statement.
logging                *Note Mailutils Configuration File: (mailutils)logging statement.
include                *Note Mailutils Configuration File: (mailutils)include.

* Menu:

* pmult-conf::     Multiplexer Configuration.
* pmult-macros::   Translating MeTA1 macros.
* pmult-client::   Pmult Client Configuration.
* pmult-debug::    Debugging Pmult.


File: mailfromd.info,  Node: pmult-conf,  Next: pmult-macros,  Up: pmult configuration

13.1.1 Multiplexer Configuration.
---------------------------------

'Pmult' listens for Pmilter requests on a socket, configured using
'listen' statement:

 -- Pmult Conf: listen URL
     Listen on the given URL.  Argument is a valid Mailutils URL.  *Note
     milter port specification::, for a description of URL.

   Since 'pmult' runs as a foreground program, it does not write its PID
number to a file by default.  If this behavior is required, it can be
enabled using the following statement:

 -- Pmult Conf: pidfile FILE
     Store PID of the 'pmult' process in FILE.

   The following three limits require MeTA1 version 'PreAlpha30.0' or
later.

 -- Pmult Conf: max-threads-soft N
     "Soft" limit on the number of 'pmilter' threads.  Default is 2.

 -- Pmult Conf: max-threads-hard N
     "Hard" limit on the number of 'pmilter' threads.  This is roughly
     equivalent to the number of emails 'pmult' is able to handle
     simultaneously.  The default value is 6.  Raise this limit if you
     experience long delays when connecting to the SMTP port.

 -- Pmult Conf: max-pmilter-fd N
     Maximum number of file descriptors 'pmilter' library is allowed to
     open simultaneously.  Default is 10.


File: mailfromd.info,  Node: pmult-macros,  Next: pmult-client,  Prev: pmult-conf,  Up: pmult configuration

13.1.2 Translating MeTA1 macros.
--------------------------------

MeTA1's notion of macros differs considerably from that of Sendmail.
Macros in MeTA1 are identified by integer numbers and only a limited
number of macros can be provided for each "Pmilter stage".  Pmilter
stages mostly correspond to Milter states (*note handler names::),
except that there are no distinct header and body stages, instead these
two are combined into a single 'data' stage.  This comes unnoticed to
mailfromd scripts, because 'pmult' takes care to invoke right Milter
handlers within the single 'data' Pmilter state.  Therefore in the
discussion that follows we will refer to Mailfromd handlers, rather than
to Pmilter stages.

   The most important standard Milter macros are always provided by
'pmult' itself.  These are:

client_addr
     The IP address of the SMTP client.  As of version 8.14, only IPv4
     addresses are supported.  Defined in all handlers.

client_port
     The port number of the SMTP client.  Defined in all handlers.

i
     MeTA1 session ID. Defined in all handlers.

f
     The envelope sender (from) address.  Defined in 'envfrom' and
     subsequent handlers.

nbadrcpts
     The number of bad recipients for a single message.  Defined in
     'envfrom' and 'envrcpt' handlers.

ntries
     The number of delivery attempts.  As of version 8.14 it is always
     '1'.  Defined in 'envfrom' and subsequent handlers.

nrcpts
     The number of validated recipients for a single message.  Defined
     in 'envfrom' and 'envrcpt' handlers.

r
     Protocol used to receive the message.  The value of this macro is
     always 'SMTP'.  Defined in all handlers.

rcpt_host
     The host from the resolved triple of the address given for the SMTP
     RCPT command.  Defined in 'envrcpt' handler.

rcpt_addr
     The address part of the resolved triple of the address given for
     the SMTP RCPT command.  Defined in 'envrcpt' handler.

s
     Sender's helo domain (parameter to 'EHLO' or 'HELO' command).

   Two additional macros are provided for all handlers that allow to
identify whether the message is processed via 'pmult':

multiplexer
     Canonical name of the multiplexer program, i.e. 'pmult'.

mult_version
     Version of 'pmult'.

   These macros can be used in mailfromd filters to provide alternative
processing for messages coming from a MeTA1 server.

   Macros defined in MeTA1 can be made available in Mailfromd handlers
using the 'define-macros' statement.

 -- Pmult Conf: define-macros HANDLER MACROS
     Define a set of Sendmail macros for the given Mailfromd handler.
     Allowed values for HANDLER are: 'connect', 'helo', 'mail' (or
     'envfrom'), 'rcpt' (or 'envrcpt'), 'data' (or 'header' or 'body'),
     'dot' ('eom').  A list of these values is also accepted, in which
     case MACROS are defined for each handler from the list.

     The second argument specifies a list of names of the macros that
     should be defined in this handler.  Allowed macro names are:

     hostname
          Hostname of SMTP server.

     client_resolve
          Result of client lookup.

     tls_version
          TLS/SSL version used.

     tls_cipher_suite
          TLS cipher suite used.

     tls_cipher_bits
          Effective key length of the symmetric encryption algorithm.

     tls_cert_subject
          The DN (distinguished name) of the presented certificate.

     tls_cert_issuer
          The DN (distinguished name) of the CA (certificate authority)
          that signed the presented certificate (the cert issuer).

     tls_alg_bits
          Maximum key length of the symmetric encryption algorithm.
          This may be less than the effective key length for export
          controlled algorithms.

     tls_vrfy
          The result of the verification of the presented cert.

     tls_cn_subject
     cn_subject
          The CN (common name) of the presented certificate.

     tls_cn_issuer
     cn_issuer
          The CN (common name) of the CA that signed the presented
          certificate.

     auth_type
          The mechanism used for SMTP authentication (only set if
          successful).

     auth_authen
          The client's authentication credentials as determined by
          authentication (only set if successful).  The actual format
          depends on the mechanism used, it might be just 'user', or
          'user@realm', or something similar.

     auth_author
          The authorization identity, i.e.  the 'AUTH=' parameter of the
          SMTP MAIL command if supplied.

     taid
          MeTA1 transaction id.

     msgid
          Message-Id of the message.

     c
          The hop count.  Basically, this is the number of 'Received:'
          headers.

     Notice the following limitations:

       1. 'taid' cannot be requested before 'mail' stage.
       2. 'msgid' can be requested only in 'dot' stage.
       3. All 'tls_*' macros are valid only after a 'STARTTLS' command.
       4. The number of MeTA1 macros per stage is limited by
          'PM_MAX_MACROS' define in 'include/sm/pmfdef.h'.  In MeTA1
          versions up to and including 1.0.PreAlpha28.0, this number is
          8.  If you need more macros, increase this number and
          recompile MeTA1.

 -- Pmult Conf: auth-macros BOOL
     If BOOL is 'true' (*note boolean: (mailutils)Statements.), pass
     auth macros to mailfromd 'mail' handler.  It is equivalent to:

          define-macros mail (auth_type, auth_authen, auth_author);


File: mailfromd.info,  Node: pmult-client,  Next: pmult-debug,  Prev: pmult-macros,  Up: pmult configuration

13.1.3 Pmult Client Configuration.
----------------------------------

In 'pmult' terminology, remote Milters are "clients".  The number of
clients 'pmult' is able to handle is not limited.  Each client is
declared using 'client' statement:

     client [IDENT] {
       # Set remote protocol type.
       type PROTOCOL-TYPE;
       # Set remote client URL.
       url ARG;
       # Set write timeout.
       write-timeout DURATION;
       # Set read timeout.
       read-timeout DURATION;
       # Set timeout for EOM.
       eom-timeout DURATION;
       # Set connect timeout.
       connect-timeout DURATION;
       # Set log verbosity level.
       log-level LEVEL;
     };

 -- Pmult Conf: client [IDENT] { STATEMENTS }
     Declare a Milter client.  Optional IDENT gives the identifier of
     this client, which will be used in diagnostics messages.

     STATEMENTS are described below.

 -- Pmult Conf: type TYPESTR
     This statement is reserved for future use.  In version 8.14 it is a
     no-op.

     If given, the value of TYPESTR must be 'milter'.

     In future versions this statement will declare the protocol to be
     used to interact with this client.  The syntax for TYPESTR is

            TYPE [VERSION]

     where TYPE is either 'milter' or 'pmilter', and optional VERSION is
     minimal protocol version.

 -- Pmult Conf: url ARG
     Set remote client URL.  *Note milter port specification::, for a
     description of URL.

 -- Pmult Conf: connect-timeout INTERVAL
     Configure Milter initial connection timeout.  Default is 300.

     *Note time interval specification::, for information on INTERVAL
     format.

 -- Pmult Conf: write-timeout INTERVAL
     Configure Milter write timeout.  Default is 10.

     *Note time interval specification::, for information on INTERVAL
     format.

 -- Pmult Conf: read-timeout INTERVAL
     Configure Milter read timeout.  Default is 10.

     *Note time interval specification::, for information on INTERVAL
     format.

 -- Pmult Conf: eom-timeout INTERVAL
     Configure Milter end of message timeout.  Default is 300.

     *Note time interval specification::, for information on INTERVAL
     format.

 -- Pmult Conf: log-level ARG
     Set Milter log verbosity level for this client.  Argument is a list
     of items separated by commas or whitespace.  Each item is a log
     level optionally prefixed with '!' to indicate "any level except
     this", '<', meaning "all levels up to and including this", or with
     '>', meaning "all levels starting from this".

     Log levels in order of increasing priority are: 'proto', 'debug',
     'info', 'warn', 'err', 'fatal'.  The first two levels are needed
     for debugging 'libgacopyz' and Milter protocol.  *Note Gacopyz::,
     for the description of the 'libgacopyz' library.  See also the
     following subsection.


File: mailfromd.info,  Node: pmult-debug,  Prev: pmult-client,  Up: pmult configuration

13.1.4 Debugging Pmult
----------------------

If needed, 'pmult' can be instructed to provide additional debugging
information.  The amount of this information is configured by three
configuration statements.  First of all, the standard 'debug' block
statement controls debugging of the underlying GNU Mailutils libraries
(*note Mailutils Configuration File: (mailutils)Debug Statement.).
Secondly, the 'debug' statement controls debugging output of the 'pmult'
utility itself.  The 'pmilter-debug' statement controls debugging output
of the underlying MeTA1 libraries, and, finally, the 'log-level'
statement, described in the previous subsection, defines debugging level
for the Milter library ('libgacopyz').

 -- Pmult Conf: debug SPEC
     Set debugging level for the 'pmult' code.  *Note Mailutils
     Configuration File: (mailutils)Debug Statement, for a description
     of SPEC syntax.  Multiplexor-specific debugging is enabled by the
     'pmult' category.  The following levels are used:

     pmult.trace1
          Prints the following information:

             * opening and closing incoming connections;
             * entering particular Pmilter stage handlers;
             * received requests with unknown command code;
             * header modification requests that does not match any
               headers.

     pmult.trace2
          Information about milter to Pmilter request translation.

     pmult.trace7
          Detailed dump of message body chunks received during Pmilter
          'DATA' stage.

     pmult.error
          Logs bad recipient addresses.

     This information is printed using the output channel defined in the
     'logging' statement (*note Mailutils Configuration File:
     (mailutils)Logging Statement.).

 -- Pmult Conf: pmilter-debug LEVEL
     Set debug verbosity level for the Pmilter library.  Argument is a
     positive integer between zero (no debugging, the default), and 100
     (maximum debugging).

     Pmilter debugging information is printed on the standard error.
     Use 'pies' 'stderr' statement to capture this stream and redirect
     it to the syslog or file (*note (pies)Output Redirectors::).


File: mailfromd.info,  Node: pmult example,  Next: pmult invocation,  Prev: pmult configuration,  Up: pmult

13.2 Pmult Example
==================

The following is an example of a working 'pmult' configuration.  The
multiplexer listens on localhost, port '3333'.  It prints its
diagnostics using syslog facility 'local2'.  A single Mailfromd client
is declared, which listens on UNIX socket
'/usr/local/var/mailfromd/mailfrom'.  The log verbosity level for this
client is set to 'info' and higher, i.e.: 'info', 'warn', 'err' and
'fatal'.

     listen inet://127.0.0.1:3333;

     logging {
        facility local2;
     };

     debug {
        level "pmult.trace7";
     }

     define-macros envmail (auth_type, auth_authen, auth_author, tls_vrfy);
     define-macros envrcpt (auth_type, auth_authen, auth_author);

     client {
        type milter;
        url /usr/local/var/mailfromd/mailfrom;
        log-level ">info";
        # Set write timeout.
        write-timeout 30 seconds;
        # Set read timeout.
        read-timeout 5 minutes;
        # Set timeout for EOM.
        eom-timeout 5 minutes;
     }


File: mailfromd.info,  Node: pmult invocation,  Prev: pmult example,  Up: pmult

13.3 Pmult Invocation
=====================

Normally, 'pmult' is invoked without command line arguments.  However,
it does support several command line options.  First of all, the common
GNU Mailutils options are understood, which are useful for checking
'pmult' configuration file for syntax errors.  *Note Common Options:
(mailutils)Common Options, for a detailed description of these.

   The rest of command line options supported by 'pmult' is useful
mostly for debugging.  These options are summarized in the table below:

'--log-tag=STRING'
     Set the identifier used in syslog messages to STRING.  This option
     mostly is for debugging purposes.  We advise to use 'logging'
     configuration statement for this purpose (*note Logging Statement:
     (mailutils)Logging Statement.).

'--no-signal-handler'
     Disable signal handling in the main thread.  This is for debugging
     purposes.

'--syslog'
     Log to the syslog.  This is the default.  *Note Logging Statement:
     (mailutils)Logging Statement, for information on how to configure
     syslog logging.

'-s'
'--stderr'
     Log to the standard error stream.

'--url=URL'
     Listen on the given URL.  This overrides the 'url' configuration
     statement (*note url: pmult-client.).

'-x'
'--debug=LEVEL'
     Set debug verbosity level.  This overrides the 'debug'
     configuration statement.  *Note pmult-debug::, for more
     information.

