Function t_lookup_request

modules/tm/t_lookup.c:391–559

 */

int t_lookup_request( struct sip_msg* p_msg , int leave_new_locked )
{
	struct cell         *p_cell;
	unsigned int       isACK;
	struct sip_msg  *t_msg;
	struct via_param *branch;
	int match_status;

	isACK = p_msg->REQ_METHOD==METHOD_ACK;

	if (isACK) {
		if (e2eack_T==NULL)
			return -1;
		if (e2eack_T!=T_UNDEFINED)
			return -2;
	}

	/* parse all*/
	if (check_transaction_quadruple(p_msg)==0) {
		LM_ERR("too few headers\n");
		set_t(0);
		/* stop processing */
		return 0;
	}

	/* start searching into the table */
	if (!p_msg->hash_index)
		p_msg->hash_index=tm_hash( p_msg->callid->body ,
			get_cseq(p_msg)->number ) ;
	LM_DBG("start searching: hash=%d, isACK=%d\n",
		p_msg->hash_index,isACK);


	/* first of all, look if there is RFC3261 magic cookie in branch; if
	 * so, we can do very quick matching and skip the old-RFC bizzar
	 * comparison of many header fields
	 */
	if (!p_msg->via1) {
		LM_ERR("no via\n");
		set_t(0);
		return 0;
	}
	branch=p_msg->via1->branch;
	if (branch && branch->value.s && branch->value.len>MCOOKIE_LEN
			&& memcmp(branch->value.s,MCOOKIE,MCOOKIE_LEN)==0) {
		/* huhuhu! the cookie is there -- let's proceed fast */
		LOCK_HASH(p_msg->hash_index);
		match_status=matching_3261(p_msg,&p_cell,
				/* skip transactions with different method; otherwise CANCEL
				 * would match the previous INVITE trans.  */
				isACK ? ~METHOD_INVITE: ~p_msg->REQ_METHOD);
		switch(match_status) {
				case 0:	goto notfound;	/* no match */
				case 1:	goto found; 	/* match */
				case 2:	goto e2e_ack;	/* e2e proxy ACK */
		}
	}