/***************************************************************************
 * http.h                                                                  *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
 *                                                                         *
 * The Nmap Security Scanner is (C) 1996-2018 Insecure.Com LLC ("The Nmap  *
 * Project"). Nmap is also a registered trademark of the Nmap Project.     *
 * This program is free software; you may redistribute and/or modify it    *
 * under the terms of the GNU General Public License as published by the   *
 * Free Software Foundation; Version 2 ("GPL"), BUT ONLY WITH ALL OF THE   *
 * CLARIFICATIONS AND EXCEPTIONS DESCRIBED HEREIN.  This guarantees your   *
 * right to use, modify, and redistribute this software under certain      *
 * conditions.  If you wish to embed Nmap technology into proprietary      *
 * software, we sell alternative licenses (contact sales@nmap.com).        *
 * Dozens of software vendors already license Nmap technology such as      *
 * host discovery, port scanning, OS detection, version detection, and     *
 * the Nmap Scripting Engine.                                              *
 *                                                                         *
 * Note that the GPL places important restrictions on "derivative works",  *
 * yet it does not provide a detailed definition of that term.  To avoid   *
 * misunderstandings, we interpret that term as broadly as copyright law   *
 * allows.  For example, we consider an application to constitute a        *
 * derivative work for the purpose of this license if it does any of the   *
 * following with any software or content covered by this license          *
 * ("Covered Software"):                                                   *
 *                                                                         *
 * o Integrates source code from Covered Software.                         *
 *                                                                         *
 * o Reads or includes copyrighted data files, such as Nmap's nmap-os-db   *
 * or nmap-service-probes.                                                 *
 *                                                                         *
 * o Is designed specifically to execute Covered Software and parse the    *
 * results (as opposed to typical shell or execution-menu apps, which will *
 * execute anything you tell them to).                                     *
 *                                                                         *
 * o Includes Covered Software in a proprietary executable installer.  The *
 * installers produced by InstallShield are an example of this.  Including *
 * Nmap with other software in compressed or archival form does not        *
 * trigger this provision, provided appropriate open source decompression  *
 * or de-archiving software is widely available for no charge.  For the    *
 * purposes of this license, an installer is considered to include Covered *
 * Software even if it actually retrieves a copy of Covered Software from  *
 * another source during runtime (such as by downloading it from the       *
 * Internet).                                                              *
 *                                                                         *
 * o Links (statically or dynamically) to a library which does any of the  *
 * above.                                                                  *
 *                                                                         *
 * o Executes a helper program, module, or script to do any of the above.  *
 *                                                                         *
 * This list is not exclusive, but is meant to clarify our interpretation  *
 * of derived works with some common examples.  Other people may interpret *
 * the plain GPL differently, so we consider this a special exception to   *
 * the GPL that we apply to Covered Software.  Works which meet any of     *
 * these conditions must conform to all of the terms of this license,      *
 * particularly including the GPL Section 3 requirements of providing      *
 * source code and allowing free redistribution of the work as a whole.    *
 *                                                                         *
 * As another special exception to the GPL terms, the Nmap Project grants  *
 * permission to link the code of this program with any version of the     *
 * OpenSSL library which is distributed under a license identical to that  *
 * listed in the included docs/licenses/OpenSSL.txt file, and distribute   *
 * linked combinations including the two.                                  *
 *                                                                         *
 * The Nmap Project has permission to redistribute Npcap, a packet         *
 * capturing driver and library for the Microsoft Windows platform.        *
 * Npcap is a separate work with it's own license rather than this Nmap    *
 * license.  Since the Npcap license does not permit redistribution        *
 * without special permission, our Nmap Windows binary packages which      *
 * contain Npcap may not be redistributed without special permission.      *
 *                                                                         *
 * Any redistribution of Covered Software, including any derived works,    *
 * must obey and carry forward all of the terms of this license, including *
 * obeying all GPL rules and restrictions.  For example, source code of    *
 * the whole work must be provided and free redistribution must be         *
 * allowed.  All GPL references to "this License", are to be treated as    *
 * including the terms and conditions of this license text as well.        *
 *                                                                         *
 * Because this license imposes special exceptions to the GPL, Covered     *
 * Work may not be combined (even as part of a larger work) with plain GPL *
 * software.  The terms, conditions, and exceptions of this license must   *
 * be included as well.  This license is incompatible with some other open *
 * source licenses as well.  In some cases we can relicense portions of    *
 * Nmap or grant special permissions to use it in other open source        *
 * software.  Please contact fyodor@nmap.org with any such requests.       *
 * Similarly, we don't incorporate incompatible open source software into  *
 * Covered Software without special permission from the copyright holders. *
 *                                                                         *
 * If you have any questions about the licensing restrictions on using     *
 * Nmap in other works, we are happy to help.  As mentioned above, we also *
 * offer an alternative license to integrate Nmap into proprietary         *
 * applications and appliances.  These contracts have been sold to dozens  *
 * of software vendors, and generally include a perpetual license as well  *
 * as providing support and updates.  They also fund the continued         *
 * development of Nmap.  Please email sales@nmap.com for further           *
 * information.                                                            *
 *                                                                         *
 * If you have received a written license agreement or contract for        *
 * Covered Software stating terms other than these, you may choose to use  *
 * and redistribute Covered Software under those terms instead of these.   *
 *                                                                         *
 * Source is provided to this software because we believe users have a     *
 * right to know exactly what a program is going to do before they run it. *
 * This also allows you to audit the software for security holes.          *
 *                                                                         *
 * Source code also allows you to port Nmap to new platforms, fix bugs,    *
 * and add new features.  You are highly encouraged to send your changes   *
 * to the dev@nmap.org mailing list for possible incorporation into the    *
 * main distribution.  By sending these changes to Fyodor or one of the    *
 * Insecure.Org development mailing lists, or checking them into the Nmap  *
 * source code repository, it is understood (unless you specify            *
 * otherwise) that you are offering the Nmap Project the unlimited,        *
 * non-exclusive right to reuse, modify, and relicense the code.  Nmap     *
 * will always be available Open Source, but this is important because     *
 * the inability to relicense code has caused devastating problems for     *
 * other Free Software projects (such as KDE and NASM).  We also           *
 * occasionally relicense the code to third parties as discussed above.    *
 * If you wish to specify special license conditions of your               *
 * contributions, just say so when you send them.                          *
 *                                                                         *
 * This program is distributed in the hope that it will be useful, but     *
 * WITHOUT ANY WARRANTY; without even the implied warranty of              *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the Nmap      *
 * license file for more details (it's in a COPYING file included with     *
 * Nmap, and also available from https://svn.nmap.org/nmap/COPYING)        *
 *                                                                         *
 ***************************************************************************/

/* $Id$ */

#ifndef _HTTP_H
#define _HTTP_H

#include "ncat_config.h"
#include "util.h"

#include <stdio.h>
#include <stdlib.h>

/* This is an abstraction over a socket (really a struct fdinfo) that provides
   rudimentary buffering. It is useful for the line-oriented parts of HTTP. */
struct socket_buffer {
    struct fdinfo fdn;
    char buffer[BUFSIZ];
    char *p;
    char *end;
};

void socket_buffer_init(struct socket_buffer *buf, int sd);

int socket_buffer_read(struct socket_buffer *buf, char *out, size_t size);

char *socket_buffer_readline(struct socket_buffer *buf, size_t *n, size_t maxlen);

int socket_buffer_readcount(struct socket_buffer *buf, char *out, size_t size);

char *socket_buffer_remainder(struct socket_buffer *buf, size_t *len);

/* A broken-down URI as defined in RFC 3986, except that the query and fragment
   parts are included in the path. */
struct uri {
    char *scheme;
    char *host;
    int port;
    char *path;
};

void uri_init(struct uri *uri);

void uri_free(struct uri *uri);

struct uri *uri_parse(struct uri *uri, const char *uri_s);

struct uri *uri_parse_authority(struct uri *uri, const char *authority);

enum http_version {
    HTTP_09,
    HTTP_10,
    HTTP_11,
    HTTP_UNKNOWN,
};

struct http_header {
    char *name;
    char *value;
    struct http_header *next;
};

struct http_request {
    char *method;
    struct uri uri;
    enum http_version version;
    struct http_header *header;
    int content_length_set;
    unsigned long content_length;
    unsigned long bytes_transferred;
};

struct http_response {
    enum http_version version;
    int code;
    char *phrase;
    struct http_header *header;
    int content_length_set;
    unsigned long content_length;
    unsigned long bytes_transferred;
};

void http_header_free(struct http_header *header);
char *http_header_get(const struct http_header *header, const char *name);
const struct http_header *http_header_next(const struct http_header *header, const struct http_header *p, const char *name);
char *http_header_get_first(const struct http_header *header, const char *name);
struct http_header *http_header_set(struct http_header *header, const char *name, const char *value);
struct http_header *http_header_remove(struct http_header *header, const char *name);
int http_header_remove_hop_by_hop(struct http_header **header);
char *http_header_to_string(const struct http_header *header, size_t *n);

void http_request_init(struct http_request *request);
void http_request_free(struct http_request *request);
char *http_request_to_string(const struct http_request *request, size_t *n);

void http_response_init(struct http_response *response);
void http_response_free(struct http_response *response);
char *http_response_to_string(const struct http_response *response, size_t *n);

int http_read_header(struct socket_buffer *buf, char **result);
int http_parse_header(struct http_header **result, const char *header);
int http_request_parse_header(struct http_request *request, const char *header);
int http_response_parse_header(struct http_response *response, const char *header);

int http_read_request_line(struct socket_buffer *buf, char **line);
int http_parse_request_line(const char *line, struct http_request *request);

int http_read_status_line(struct socket_buffer *buf, char **line);
int http_parse_status_line(const char *line, struct http_response *response);
int http_parse_status_line_code(const char *line);

enum http_auth_scheme { AUTH_UNKNOWN, AUTH_BASIC, AUTH_DIGEST };
enum http_digest_algorithm { ALGORITHM_MD5, ALGORITHM_UNKNOWN };
enum http_digest_qop { QOP_NONE = 0, QOP_AUTH = 1 << 0, QOP_AUTH_INT = 1 << 1 };

struct http_challenge {
    enum http_auth_scheme scheme;
    char *realm;
    struct {
        char *nonce;
        char *opaque;
        enum http_digest_algorithm algorithm;
        /* A bit mask of supported qop values ("auth", "auth-int", etc.). */
        unsigned char qop;
    } digest;
};

struct http_credentials {
    enum http_auth_scheme scheme;
    union {
        char *basic;
        struct {
            char *username;
            char *realm;
            char *nonce;
            char *uri;
            char *response;
            enum http_digest_algorithm algorithm;
            enum http_digest_qop qop;
            char *nc;
            char *cnonce;
        } digest;
    } u;
};

void http_challenge_init(struct http_challenge *challenge);
void http_challenge_free(struct http_challenge *challenge);
struct http_challenge *http_header_get_proxy_challenge(const struct http_header *header, struct http_challenge *challenge);

void http_credentials_init_basic(struct http_credentials *credentials);
void http_credentials_init_digest(struct http_credentials *credentials);
void http_credentials_free(struct http_credentials *credentials);
struct http_credentials *http_header_get_proxy_credentials(const struct http_header *header, struct http_credentials *credentials);

#if HAVE_HTTP_DIGEST
/* Initialize the server secret used in generating nonces. */
int http_digest_init_secret(void);
int http_digest_nonce_time(const char *nonce, struct timeval *tv);
/* Return a Proxy-Authenticate header. */
char *http_digest_proxy_authenticate(const char *realm, int stale);
/* Return a Proxy-Authorization header answering the given challenge. */
char *http_digest_proxy_authorization(const struct http_challenge *challenge,
    const char *username, const char *password,
    const char *method, const char *uri);
int http_digest_check_credentials(const char *username, const char *realm,
    const char *password, const char *method,
    const struct http_credentials *credentials);
#endif

#endif
