loose.c

用来作为linux中SIP SERVER,完成VOIP网络电话中服务器的功能

/*
 * Route & Record-Route module, loose routing support
 *
 * $Id: loose.c,v 1.35.2.1 2005/05/31 13:48:30 janakj Exp $
 *
 * Copyright (C) 2001-2004 FhG Fokus
 *
 * This file is part of ser, a free SIP server.
 *
 * ser is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * For a license to use the ser software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact iptel.org by e-mail at the following addresses:
 *    [e-mail]
 *
 * ser 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
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * History:
 * ---------
 * 2003-02-28 scratchpad compatibility abandoned (jiri)
 * 2003-01-27 next baby-step to removing ZT - PRESERVE_ZT (jiri)
 */


#include <string.h>
#include "../../ut.h"
#include "../../str.h"
#include "../../dprint.h"
#include "../../forward.h"
#include "../../data_lump.h"
#include "../../parser/parse_rr.h"
#include "../../parser/parse_uri.h"
#include "../../mem/mem.h"
#include "../../dset.h"
#include "loose.h"
#include "rr_mod.h"


#define RR_ERROR -1       /* An error occured while processing route set */
#define RR_DRIVEN 1       /* The next hop is determined from the route set */
#define NOT_RR_DRIVEN -1  /* The next hop is not determined from the route set */

#define ROUTE_PREFIX "Route: <"
#define ROUTE_PREFIX_LEN (sizeof(ROUTE_PREFIX)-1)

#define ROUTE_SUFFIX ">\r\n"
#define ROUTE_SUFFIX_LEN (sizeof(ROUTE_SUFFIX)-1)


/*
 * Test whether we are processing pre-loaded route set
 * by looking at the To tag
 */
static int is_preloaded(struct sip_msg* msg)
{
	str tag;

	if (!msg->to && parse_headers(msg, HDR_TO, 0) == -1) {
		LOG(L_ERR, "is_preloaded: Cannot parse To header field\n");
		return -1;
	}

	if (!msg->to) {
		LOG(L_ERR, "is_preloaded: To header field not found\n");
		return -1;
	}

	tag = get_to(msg)->tag_value;
	if (tag.s == 0 || tag.len == 0) {
		DBG("is_preloaded: Yes\n");
		return 1;
	}

	DBG("is_preloaded: No\n");
	return 0;
}


/*
 * Parse the message and find first occurrence of
 * Route header field. The function returns -1 or -2 
 * on a parser error, 0 if there is a Route HF and
 * 1 if there is no Route HF.
 */
static inline int find_first_route(struct sip_msg* _m)
{
	if (parse_headers(_m, HDR_ROUTE, 0) == -1) {
		LOG(L_ERR, "find_first_route: Error while parsing headers\n");
		return -1;
	} else {
		if (_m->route) {
			if (parse_rr(_m->route) < 0) {
				LOG(L_ERR, "find_first_route: Error while parsing Route HF\n");
				return -2;
			}
			return 0;
		} else {
			DBG("find_first_route: No Route headers found\n");
			return 1;
		}
	}
}


/*
 * Find out if a URI contains r2 parameter which indicates
 * that we put 2 record routes
 */
static inline int is_2rr(str* _params)
{
	str s;
	int i, state = 0;

	if (_params->len == 0) return 0;
	s = *_params;

	for(i = 0; i < s.len; i++) {
		switch(state) {
		case 0:
			switch(s.s[i]) {
			case ' ':
			case '\r':
			case '\n':
			case '\t':           break;
			case 'r':
			case 'R': state = 1; break;
			default:  state = 4; break;
			}
			break;

		case 1:
			switch(s.s[i]) {
			case '2': state = 2; break;
			default:  state = 4; break;
			}
			break;

		case 2:
			switch(s.s[i]) {
			case ';':  return 1;
			case '=':  return 1;
			case ' ':
			case '\r':
			case '\n':
			case '\t': state = 3; break;
			default:   state = 4; break;
			}
			break;

		case 3:
			switch(s.s[i]) {
			case ';':  return 1;
			case '=':  return 1;
			case ' ':
			case '\r':
			case '\n':
			case '\t': break;
			default:   state = 4; break;
			}
			break;

		case 4:
			switch(s.s[i]) {
			case '\"': state = 5; break;
			case ';':  state = 0; break;
			default:              break;
			}
			break;
			
		case 5:
			switch(s.s[i]) {
			case '\\': state = 6; break;
			case '\"': state = 4; break;
			default:              break;
			}
			break;

		case 6: state = 5; break;
		}
	}
	
	if ((state == 2) || (state == 3)) return 1;
	else return 0;
}


/*
 * Check if URI is myself
 */
#ifdef ENABLE_USER_CHECK
static inline int is_myself(str *_user, str* _host, unsigned short _port)
#else
static inline int is_myself(str* _host, unsigned short _port)
#endif
{
	int ret;
	
	ret = check_self(_host, _port ? _port : SIP_PORT, 0);/* match all protos*/
	if (ret < 0) return 0;

#ifdef ENABLE_USER_CHECK
	if(i_user.len && i_user.len==_user->len
			&& !strncmp(i_user.s, _user->s, _user->len))
	{
		DBG("is_myself: this URI isn't mine\n");
		return -1;
	}
#endif
	
	return ret;
}


/*
 * Find and parse next Route header field
 */
static inline int find_next_route(struct sip_msg* _m, struct hdr_field** _hdr)
{
	struct hdr_field* ptr;

	ptr = (*_hdr)->next;

	     /* Try to find already parsed Route headers */
	while(ptr) {
		if (ptr->type == HDR_ROUTE) goto found;
		ptr = ptr->next;
	}

	     /* There are no already parsed Route headers, try to find next
	      * occurrence of Route header
	      */
	if (parse_headers(_m, HDR_ROUTE, 1) == -1) {
		LOG(L_ERR, "find_next_route: Error while parsing headers\n");
		return -1;
	}

	if ((_m->last_header->type != HDR_ROUTE) || (_m->last_header == *_hdr)) {
		DBG("find_next_route: No next Route HF found\n");
		return 1;
	}

	ptr = _m->last_header;

 found:
	if (parse_rr(ptr) < 0) {
		LOG(L_ERR, "find_next_route: Error while parsing Route body\n");
		return -2;
	}

	*_hdr = ptr;
	return 0;
}


/*
 * Check if the given uri contains lr parameter which marks loose routers
 */
static inline int is_strict(str* _params)
{
	str s;
	int i, state = 0;

	if (_params->len == 0) return 1;

	s.s = _params->s;
	s.len = _params->len;

	for(i = 0; i < s.len; i++) {
		switch(state) {
		case 0:
			switch(s.s[i]) {
			case ' ':
			case '\r':
			case '\n':
			case '\t':           break;
			case 'l':
			case 'L': state = 1; break;
			default:  state = 4; break;
			}
			break;

		case 1:
			switch(s.s[i]) {
			case 'r':
			case 'R': state = 2; break;
			default:  state = 4; break;
			}
			break;

		case 2:
			switch(s.s[i]) {
			case ';':  return 0;
			case '=':  return 0;
			case ' ':
			case '\r':
			case '\n':
			case '\t': state = 3; break;
			default:   state = 4; break;
			}
			break;

		case 3:
			switch(s.s[i]) {
			case ';':  return 0;
			case '=':  return 0;
			case ' ':
			case '\r':
			case '\n':
			case '\t': break;
			default:   state = 4; break;
			}
			break;

		case 4:
			switch(s.s[i]) {
			case '\"': state = 5; break;
			case ';':  state = 0; break;
			default:              break;
			}
			break;
			
		case 5:
			switch(s.s[i]) {
			case '\\': state = 6; break;
			case '\"': state = 4; break;
			default:              break;
			}
			break;

		case 6: state = 5; break;
		}
	}
	
	if ((state == 2) || (state == 3)) return 0;
	else return 1;
}


/*
 * Put Request-URI as last Route header of a SIP
 * message, this is necessary when forwarding to
 * a strict router
 */
static inline int save_ruri(struct sip_msg* _m)
{
	struct lump* anchor;
	char *s;
	int len;

	     /* We must parse the whole message header here,
	      * because Request-URI must be saved in last
	      * Route HF in the message
	      */
	if (parse_headers(_m, HDR_EOH, 0) == -1) {
		LOG(L_ERR, "save_ruri: Error while parsing message\n");
		return -1;
	}

	     /* Create an anchor */
	anchor = anchor_lump(_m, _m->unparsed - _m->buf, 0, 0);
	if (anchor == 0) {
		LOG(L_ERR, "save_ruri: Can't get anchor\n");
		return -2;
	}

	     /* Create buffer for new lump */
	len = ROUTE_PREFIX_LEN + _m->first_line.u.request.uri.len + ROUTE_SUFFIX_LEN;
	s = (char*)pkg_malloc(len);
	if (!s) {
		LOG(L_ERR, "save_ruri: No memory left\n");
		return -3;
	}

	     /* Create new header field */
	memcpy(s, ROUTE_PREFIX, ROUTE_PREFIX_LEN);
	memcpy(s + ROUTE_PREFIX_LEN, _m->first_line.u.request.uri.s, _m->first_line.u.request.uri.len);
	memcpy(s + ROUTE_PREFIX_LEN + _m->first_line.u.request.uri.len, ROUTE_SUFFIX, ROUTE_SUFFIX_LEN);

	DBG("save_ruri: New header: '%.*s'\n", len, ZSW(s));

	     /* Insert it */
	if (insert_new_lump_before(anchor, s, len, 0) == 0) {