mf_funcs.c

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

/*
 * $Id: mf_funcs.c,v 1.24.2.2 2005/03/25 17:37:33 andrei Exp $
 *
 * Copyright (C) 2001-2003 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)
 * 2002-01-28 scratchpad removed (jiri)
 * 2004-08-15 max value of max-fwd header is configurable (bogdan)
 */


#include <stdlib.h>
#include <string.h>

#include "../../comp_defs.h"
#include "mf_funcs.h"
#include "../../mem/mem.h"
#include "../../ut.h"
#include "../../data_lump.h"


#define MF_HDR "Max-Forwards: "
#define MF_HDR_LEN (sizeof(MF_HDR) - 1)


/* looks for the MAX FORWARDS header
   returns the its value, -1 if is not present or -2 for error */
int is_maxfwd_present( struct sip_msg* msg , str *foo)
{
	int x, err;

	/* lookup into the message for MAX FORWARDS header*/
	if ( !msg->maxforwards ) {
		if  ( parse_headers( msg , HDR_MAXFORWARDS, 0 )==-1 ){
			LOG( L_ERR , "ERROR:maxfwd:is_maxfwd_present :"
				" parsing MAX_FORWARD header failed!\n");
			return -2;
		}
		if (!msg->maxforwards) {
			DBG("DEBUG: is_maxfwd_present: max_forwards header not found!\n");
			return -1;
		}
	}

	/* if header is present, trim to get only the string containing numbers */
	trim_len( foo->len , foo->s , msg->maxforwards->body );

	/* convert from string to number */
	x = str2s( foo->s,foo->len,&err);
	if (err){
		LOG(L_ERR, "ERROR:maxfwd:is_maxfwd_present:"
			" unable to parse the max forwards number !\n");
		return -2;
	}
	DBG("DEBUG:maxfwd:is_maxfwd_present: value = %d \n",x);
	return x;
}




int decrement_maxfwd( struct sip_msg* msg , int x, str *s)
{
	int i;

	/* double check */
	if ( !msg->maxforwards ) {
		LOG( L_ERR , "ERROR: decrement_maxfwd :"
			" MAX_FORWARDS header not found !\n");
		goto error;
	}

	/*rewriting the max-fwd value in the message (buf and orig)*/
	x--;
	for(i = s->len - 1; i >= 0; i--) {
		s->s[i] = (x % 10) + '0';
		x /= 10;
		if (x==0) {
		    i = i - 1;
		    break;
		}
	}
	while(i >= 0) s->s[i--] = ' ';

	return 1;
error:
	return -1;
}




int add_maxfwd_header( struct sip_msg* msg , unsigned int val )
{
	unsigned int  len;
	char          *buf;
	struct lump*  anchor;

	/* double check just to be sure */
	if ( msg->maxforwards ) {
		LOG( L_ERR , "ERROR: add_maxfwd_header :"
			" MAX_FORWARDS header already exists (%p) !\n",msg->maxforwards);
		goto error;
	}

	/* constructing the header */
	len = MF_HDR_LEN /*"MAX-FORWARDS: "*/+ CRLF_LEN + 3/*val max on 3 digits*/;

	buf = (char*)pkg_malloc( len );
	if (!buf) {
		LOG(L_ERR, "ERROR : add_maxfwd_header : No memory left\n");
		return -1;
	}
	memcpy( buf , MF_HDR, MF_HDR_LEN );
	len = MF_HDR_LEN ;
	len += btostr( buf+len , val );
	memcpy( buf+len , CRLF , CRLF_LEN );
	len +=CRLF_LEN;

	/*inserts the header at the beginning of the message*/
	anchor = anchor_lump(msg, msg->headers->name.s - msg->buf, 0 , 0);
	if (anchor == 0) {
		LOG(L_ERR, "ERROR: add_maxfwd_header :"
		   " Error, can't get anchor\n");
		goto error1;
	}

	if (insert_new_lump_before(anchor, buf, len, 0) == 0) {
		LOG(L_ERR, "ERROR: add_maxfwd_header : "
		    "Error, can't insert MAX-FORWARDS\n");
		goto error1;
	}

	return 1;

error1:
	pkg_free( buf );
error:
	return -1;
}