/*
 * - utility for generating to-tags
 *   in Kamailio, to-tags consist of two parts: a fixed part
 *   which is bound to server instance and variable part
 *   which is bound to request -- that helps to recognize,
 *   who generated the to-tag in loops through the same
 *   server -- in such cases, fixed part is constant, but
 *   the variable part varies because it depends on
 *   via
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef _TAGS_H
#define _TAGS_H

#include "parser/msg_parser.h"
#include "globals.h"
#include "crc.h"
#include "str.h"
#include "socket_info.h"

#define TOTAG_VALUE_LEN (MD5_LEN + CRC32_LEN + 1)

/*! generate variable part of to-tag for a request;
 * it will have length of CRC32_LEN, sufficiently
 * long buffer must be passed to the function */
static inline void calc_crc_suffix(struct sip_msg *msg, char *tag_suffix)
{
	int ss_nr;
	str suffix_source[3];

	ss_nr = 2;
	if(msg->via1 == 0)
		return; /* no via, bad message */
	suffix_source[0] = msg->via1->host;
	suffix_source[1] = msg->via1->port_str;
	if(msg->via1->branch) {
		suffix_source[ss_nr++] = msg->via1->branch->value;
	} else {
		suffix_source[2].s = NULL;
		suffix_source[2].len = 0;
	}
	crcitt_string_array(tag_suffix, suffix_source, ss_nr);

	ss_nr = 2;
	suffix_source[0] = msg->via1->port_str;
	suffix_source[1] = msg->via1->host;
	if(msg->callid) {
		suffix_source[ss_nr++] = msg->callid->body;
	} else {
		suffix_source[2].s = NULL;
		suffix_source[2].len = 0;
	}
	crcitt_string_array(tag_suffix + 4, suffix_source, ss_nr);
}

static void inline init_tags(
		char *tag, char **suffix, char *signature, char separator)
{
	str src[3];
	struct socket_info *si;

	si = get_first_socket();
	src[0].s = signature;
	src[0].len = strlen(signature);
	/* if we are not listening on anything we shouldn't be here */
	src[1].s = si ? si->address_str.s : "";
	src[1].len = si ? si->address_str.len : 0;
	src[2].s = si ? si->port_no_str.s : "";
	src[2].len = si ? si->port_no_str.len : 0;

	MD5StringArray(tag, src, 3);

	tag[MD5_LEN] = separator;
	*suffix = tag + MD5_LEN + 1;
}


#endif
