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/* $Id$
*
* Copyright (C) 2005 Voice System SRL
*
* 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
*
* History:
* ---------
* 2005-07-11 created (bogdan)
*/
#ifndef NATHELPER_OPTIONS_H_
#define NATHELPER_OPTIONS_H_
#include <stdlib.h>
#include <string.h>
#include "../../parser/parse_rr.h"
#include "../../str.h"
#include "../../ut.h"
#include "../../ip_addr.h"
/* size of buffer used for building SIP PING req */
#define MAX_SIPPING_SIZE 65536
/* helping macros for building SIP PING ping request */
#define append_fix( _p, _s) \
do {\
memcpy(_p, _s, sizeof(_s)-1);\
_p += sizeof(_s)-1;\
}while(0)
/* info used to generate SIP ping requests */
static int sipping_fromtag = 0;
static char sipping_callid_buf[8];
static int sipping_callid_cnt = 0;
static str sipping_callid = {0,0};
static str sipping_from = STR_NULL;
static str sipping_method = str_init("OPTIONS");
static void init_sip_ping(void)
{
int len;
char *p;
/* FROM tag - some random number */
sipping_fromtag = rand();
/* callid fix part - hexa string */
len = 8;
p = sipping_callid_buf;
int2reverse_hex( &p, &len, rand() );
sipping_callid.s = sipping_callid_buf;
sipping_callid.len = 8-len;
/* callid counter part */
sipping_callid_cnt = rand();
}
static int sipping_rpl_filter(struct sip_msg *rpl)
{
struct cseq_body* cseq_b;
/* first check number of vias -> must be only one */
if (parse_headers( rpl, HDR_VIA2_F, 0 )==-1 || (rpl->via2!=0))
goto skip;
/* check the method -> we need CSeq header */
if ( (!rpl->cseq && parse_headers(rpl,HDR_CSEQ_F,0)!=0) || rpl->cseq==0 ) {
LM_ERR("failed to parse CSeq\n");
goto error;
}
cseq_b = (struct cseq_body*)rpl->cseq->parsed;
if (cseq_b->method.len!=sipping_method.len ||
strncmp(cseq_b->method.s,sipping_method.s,sipping_method.len)!=0)
goto skip;
/* check constant part of callid */
if ( (!rpl->callid && parse_headers(rpl,HDR_CALLID_F,0)!=0) ||
rpl->callid==0 ) {
LM_ERR("failed to parse Call-ID\n");
goto error;
}
if ( rpl->callid->body.len<=sipping_callid.len+1 ||
strncmp(rpl->callid->body.s,sipping_callid.s,sipping_callid.len)!=0 ||
rpl->callid->body.s[sipping_callid.len]!='-')
goto skip;
LM_DBG("reply for SIP natping filtered\n");
/* it's a reply to a SIP NAT ping -> absorb it and stop any
* further processing of it */
return 0;
skip:
return 1;
error:
return -1;
}
/* build the buffer of a SIP ping request */
static inline char* build_sipping(str *curi, struct socket_info* s, str *path,
str *ruid, unsigned int aorhash, int *len_p)
{
#define s_len(_s) (sizeof(_s)-1)
static char buf[MAX_SIPPING_SIZE];
char *p;
int len;
if ( sipping_method.len + 1 + curi->len + s_len(" SIP/2.0"CRLF) +
s_len("Via: SIP/2.0/UDP ") + s->address_str.len +
1 + s->port_no_str.len + s_len(";branch=0") +
(path->len ? (s_len(CRLF"Route: ") + path->len) : 0) +
s_len(CRLF"From: ") + sipping_from.len + s_len(";tag=") +
ruid->len + 1 + 8 + 1 + 8 +
s_len(CRLF"To: ") + curi->len +
s_len(CRLF"Call-ID: ") + sipping_callid.len + 1 + 8 + 1 + 8 + 1 +
s->address_str.len +
s_len(CRLF"CSeq: 1 ") + sipping_method.len +
s_len(CRLF"Content-Length: 0" CRLF CRLF)
> MAX_SIPPING_SIZE )
{
LM_ERR("len exceeds %d\n",MAX_SIPPING_SIZE);
return 0;
}
p = buf;
append_str( p, sipping_method.s, sipping_method.len);
*(p++) = ' ';
append_str( p, curi->s, curi->len);
append_fix( p, " SIP/2.0"CRLF"Via: SIP/2.0/UDP ");
append_str( p, s->address_str.s, s->address_str.len);
*(p++) = ':';
append_str( p, s->port_no_str.s, s->port_no_str.len);
if (path->len) {
append_fix( p, ";branch=0"CRLF"Route: ");
append_str( p, path->s, path->len);
append_fix( p, CRLF"From: ");
} else {
append_fix( p, ";branch=0"CRLF"From: ");
}
append_str( p, sipping_from.s, sipping_from.len);
append_fix( p, ";tag=");
append_str( p, ruid->s, ruid->len);
*(p++) = '-';
len = 8;
int2reverse_hex( &p, &len, aorhash );
*(p++) = '-';
len = 8;
int2reverse_hex( &p, &len, sipping_fromtag++ );
append_fix( p, CRLF"To: ");
append_str( p, curi->s, curi->len);
append_fix( p, CRLF"Call-ID: ");
append_str( p, sipping_callid.s, sipping_callid.len);
*(p++) = '-';
len = 8;
int2reverse_hex( &p, &len, sipping_callid_cnt++ );
*(p++) = '-';
len = 8;
int2reverse_hex( &p, &len, get_ticks() );
*(p++) = '@';
append_str( p, s->address_str.s, s->address_str.len);
append_fix( p, CRLF"CSeq: 1 ");
append_str( p, sipping_method.s, sipping_method.len);
append_fix( p, CRLF"Content-Length: 0" CRLF CRLF);
*len_p = p - buf;
return buf;
}
#endif
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