t_lookup.c

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

	{
		t_msg = p_cell->uas.request;

		if (!t_msg) continue; /* skip UAC transactions */

		if (!isACK) {	
			/* compare lengths first */ 
			if (!EQ_LEN(callid)) continue;
			if (!EQ_LEN(cseq)) continue;
			if (!EQ_LEN(from)) continue;
			if (!EQ_LEN(to)) continue;
			if (ruri_matching && !EQ_REQ_URI_LEN) continue;
			if (via1_matching && !EQ_VIA_LEN(via1)) continue;

			/* length ok -- move on */
			if (!EQ_STR(callid)) continue;
			if (!EQ_STR(cseq)) continue;
			if (!EQ_STR(from)) continue;
			if (!EQ_STR(to)) continue;
			if (ruri_matching && !EQ_REQ_URI_STR) continue;
			if (via1_matching && !EQ_VIA_STR(via1)) continue;

			/* request matched ! */
			DBG("DEBUG: non-ACK matched\n");
			goto found;
		} else { /* it's an ACK request*/
			/* ACK's relate only to INVITEs */
			if (t_msg->REQ_METHOD!=METHOD_INVITE) continue;

			/* From|To URI , CallID, CSeq # must be always there */
			/* compare lengths now */
			if (!EQ_LEN(callid)) continue;
			/* CSeq only the number without method ! */
			if (get_cseq(t_msg)->number.len!=get_cseq(p_msg)->number.len)
				continue;
			if (! EQ_LEN(from)) continue;
			/* To only the uri -- to many UACs screw up tags  */
			if (get_to(t_msg)->uri.len!=get_to(p_msg)->uri.len)
				continue;
			if (!EQ_STR(callid)) continue;
			if (memcmp(get_cseq(t_msg)->number.s, get_cseq(p_msg)->number.s,
				get_cseq(p_msg)->number.len)!=0) continue;
			if (!EQ_STR(from)) continue;
			if (memcmp(get_to(t_msg)->uri.s, get_to(p_msg)->uri.s,
				get_to(t_msg)->uri.len)!=0) continue;

			/* it is e2e ACK/200 */
			if (p_cell->uas.status<300 && e2e_ack_trans==0) {
				/* all criteria for proxied ACK are ok */
				if (p_cell->relaied_reply_branch!=-2) {
					e2e_ack_trans=p_cell;
					continue;
				}
				/* it's a local UAS transaction */
				if (dlg_matching(p_cell, p_msg))
					goto found;
				continue;
			}

			/* it is not an e2e ACK/200 -- perhaps it is 
			 * local negative case; in which case we will want
			 * more elements to match: r-uri and via; allow
			 * mismatching r-uri as an config option for broken
			 * UACs */
			if (ruri_matching && !EQ_REQ_URI_LEN ) continue;
			if (via1_matching && !EQ_VIA_LEN(via1)) continue;
			if (ruri_matching && !EQ_REQ_URI_STR) continue;
			if (via1_matching && !EQ_VIA_STR(via1)) continue;

			/* wow -- we survived all the check! we matched! */
			DBG("DEBUG: non-2xx ACK matched\n");
			goto found;
		} /* ACK */
	} /* synonym loop */

notfound:

	if (e2e_ack_trans) {
		p_cell=e2e_ack_trans;
		goto e2e_ack;
	}
		
	/* no transaction found */
	set_t(0);
	if (!leave_new_locked) {
		UNLOCK_HASH(p_msg->hash_index);
	}
	DBG("DEBUG: t_lookup_request: no transaction found\n");
	return -1;

e2e_ack:
	t_ack=p_cell;	/* e2e proxied ACK */
	set_t(0);
	if (!leave_new_locked) {
		UNLOCK_HASH(p_msg->hash_index);
	}
	DBG("DEBUG: t_lookup_request: e2e proxy ACK found\n");
	return -2;

found:
	set_t(p_cell);
	REF_UNSAFE( T );
	set_kr(REQ_EXIST);
	UNLOCK_HASH( p_msg->hash_index );
	DBG("DEBUG: t_lookup_request: transaction found (T=%p)\n",T);
	return 1;
}



/* function lookups transaction being canceled by CANCEL in p_msg;
 * it returns:
 *       0 - transaction wasn't found
 *       T - transaction found
 */
struct cell* t_lookupOriginalT(  struct sip_msg* p_msg )
{
	struct cell     *p_cell;
	unsigned int     hash_index;
	struct sip_msg  *t_msg;
	struct via_param *branch;
	int ret;


	/* start searching in the table */
	hash_index = p_msg->hash_index;
	DBG("DEBUG: t_lookupOriginalT: searching on hash entry %d\n",hash_index );


	/* 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) {
		LOG(L_ERR, "ERROR: t_lookupOriginalT: 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(hash_index);
		ret=matching_3261(p_msg, &p_cell,
				/* we are seeking the original transaction --
				 * skip CANCEL transactions during search
				 */
				METHOD_CANCEL);
		if (ret==1) goto found; else goto notfound;
	}

	/* no cookies --proceed to old-fashioned pre-3261 t-matching */

	LOCK_HASH(hash_index);

	/* all the transactions from the entry are compared */
	for (p_cell=get_tm_table()->entrys[hash_index].first_cell;
		p_cell; p_cell = p_cell->next_cell )
	{
		t_msg = p_cell->uas.request;

		if (!t_msg) continue; /* skip UAC transactions */

		/* we don't cancel CANCELs ;-) */
		if (t_msg->REQ_METHOD==METHOD_CANCEL)
			continue;

		/* check lengths now */	
		if (!EQ_LEN(callid))
			continue;
		if (get_cseq(t_msg)->number.len!=get_cseq(p_msg)->number.len)
			continue;
		if (!EQ_LEN(from))
			continue;
#ifdef CANCEL_TAG
		if (!EQ_LEN(to))
			continue;
#else
		/* relaxed matching -- we don't care about to-tags anymore,
		 * many broken UACs screw them up and ignoring them does not
		 * actually hurt
		 */
		if (get_to(t_msg)->uri.len!=get_to(p_msg)->uri.len)
			continue;
#endif
		if (ruri_matching && !EQ_REQ_URI_LEN)
			continue;
		if (via1_matching && !EQ_VIA_LEN(via1))
			continue;

		/* check the content now */
		if (!EQ_STR(callid))
			continue;
		if (memcmp(get_cseq(t_msg)->number.s,
			get_cseq(p_msg)->number.s,get_cseq(p_msg)->number.len)!=0)
			continue;
		if (!EQ_STR(from))
			continue;
#ifdef CANCEL_TAG
		if (!EQ_STR(to))
			continue;
#else
		if (memcmp(get_to(t_msg)->uri.s, get_to(p_msg)->uri.s,
					get_to(t_msg)->uri.len)!=0)
			continue;
#endif
		if (ruri_matching && !EQ_REQ_URI_STR)
			continue;
		if (via1_matching && !EQ_VIA_STR(via1))
			continue;

		/* found */
		goto found;
	}

notfound:
	/* no transaction found */
	DBG("DEBUG: t_lookupOriginalT: no CANCEL matching found! \n" );
	UNLOCK_HASH(hash_index);
	DBG("DEBUG: t_lookupOriginalT completed\n");
	return 0;

found:
	DBG("DEBUG: t_lookupOriginalT: canceled transaction"
		" found (%p)! \n",p_cell );
	REF_UNSAFE( p_cell );
	UNLOCK_HASH(hash_index);
	DBG("DEBUG: t_lookupOriginalT completed\n");
	return p_cell;
}




/* Returns 0 - nothing found
 *         1  - T found
 */
int t_reply_matching( struct sip_msg *p_msg , int *p_branch )
{
	struct cell*  p_cell;
	int hash_index   = 0;
	int entry_label  = 0;
	int branch_id    = 0;
	char  *hashi, *branchi, *p, *n;
	int hashl, branchl;
	int scan_space;
	str cseq_method;
	str req_method;

	char *loopi;
	int loopl;
	char *syni;
	int synl;
	
	short is_cancel;

	/* make compiler warnings happy */
	loopi=0;
	loopl=0;
	syni=0;
	synl=0;

	/* split the branch into pieces: loop_detection_check(ignored),
	 hash_table_id, synonym_id, branch_id */

	if (!(p_msg->via1 && p_msg->via1->branch && p_msg->via1->branch->value.s))
		goto nomatch2;

	/* we do RFC 3261 tid matching and want to see first if there is
	 * magic cookie in branch */
	if (p_msg->via1->branch->value.len<=MCOOKIE_LEN)
		goto nomatch2;
	if (memcmp(p_msg->via1->branch->value.s, MCOOKIE, MCOOKIE_LEN)!=0)
		goto nomatch2;

	p=p_msg->via1->branch->value.s+MCOOKIE_LEN;
	scan_space=p_msg->via1->branch->value.len-MCOOKIE_LEN;


	/* hash_id */
	n=eat_token2_end( p, p+scan_space, BRANCH_SEPARATOR);
	hashl=n-p;
	scan_space-=hashl;
	if (!hashl || scan_space<2 || *n!=BRANCH_SEPARATOR) goto nomatch2;
	hashi=p;
	p=n+1;scan_space--;

	if (!syn_branch) {
		/* md5 value */
		n=eat_token2_end( p, p+scan_space, BRANCH_SEPARATOR );
		loopl = n-p;
		scan_space-= loopl;
		if (n==p || scan_space<2 || *n!=BRANCH_SEPARATOR) 
			goto nomatch2;
		loopi=p;
		p=n+1; scan_space--;
	} else {
		/* synonym id */
		n=eat_token2_end( p, p+scan_space, BRANCH_SEPARATOR);
		synl=n-p;
		scan_space-=synl;
		if (!synl || scan_space<2 || *n!=BRANCH_SEPARATOR) 
			goto nomatch2;
		syni=p;
		p=n+1;scan_space--;
	}

	/* branch id  -  should exceed the scan_space */
	n=eat_token_end( p, p+scan_space );
	branchl=n-p;
	if (!branchl ) goto nomatch2;
	branchi=p;

	/* sanity check */
	if ((hash_index=reverse_hex2int(hashi, hashl))<0
		||hash_index>=TABLE_ENTRIES
		|| (branch_id=reverse_hex2int(branchi, branchl))<0
		||branch_id>=MAX_BRANCHES
		|| (syn_branch ? (entry_label=reverse_hex2int(syni, synl))<0 
			: loopl!=MD5_LEN )
	) {
		DBG("DEBUG: t_reply_matching: poor reply labels %d label %d "
			"branch %d\n",hash_index, entry_label, branch_id );
		goto nomatch2;
	}


	DBG("DEBUG: t_reply_matching: hash %d label %d branch %d\n",
		hash_index, entry_label, branch_id );


	/* search the hash table list at entry 'hash_index'; lock the
	   entry first 
	*/
	cseq_method=get_cseq(p_msg)->method;
	is_cancel=cseq_method.len==CANCEL_LEN 
		&& memcmp(cseq_method.s, CANCEL, CANCEL_LEN)==0;
	LOCK_HASH(hash_index);
	for (p_cell = get_tm_table()->entrys[hash_index].first_cell; p_cell; 
		p_cell=p_cell->next_cell) {

		/* first look if branch matches */

		if (syn_branch) {
			if (p_cell->label != entry_label) 
				continue;
		} else {
			if ( memcmp(p_cell->md5, loopi,MD5_LEN)!=0)
					continue;
		}

		/* sanity check ... too high branch ? */
		if ( branch_id>=p_cell->nr_of_outgoings )
			continue;

		/* does method match ? (remember -- CANCELs have the same branch
		   as canceled transactions) */
		req_method=p_cell->method;
		if ( /* method match */
			! ((cseq_method.len==req_method.len 
			&& memcmp( cseq_method.s, req_method.s, cseq_method.len )==0)
			/* or it is a local cancel */
			|| (is_cancel && is_invite(p_cell)
				/* commented out -- should_cancel_branch set it to
				   BUSY_BUFFER to avoid collisions with replies;
				   thus, we test here by buffer size
				*/
				/* && p_cell->uac[branch_id].local_cancel.buffer ))) */
				&& p_cell->uac[branch_id].local_cancel.buffer_len ))) 
			continue;


		/* we passed all disqualifying factors .... the transaction has been
		   matched !
		*/
		set_t(p_cell);
		*p_branch = branch_id;
		REF_UNSAFE( T );
		UNLOCK_HASH(hash_index);
		DBG("DEBUG: t_reply_matching: reply matched (T=%p)!\n",T);
		/* if this is a 200 for INVITE, we will wish to store to-tags to be
		 * able to distinguish retransmissions later and not to call
 		 * TMCB_RESPONSE_OUT uselessly; we do it only if callbacks are
		 * enabled -- except callback customers, nobody cares about 
		 * retransmissions of multiple 200/INV or ACK/200s
		 */
		if (is_invite(p_cell) && p_msg->REPLY_STATUS>=200 
		&& p_msg->REPLY_STATUS<300 
		&& ( (!is_local(p_cell) &&
				has_tran_tmcbs(p_cell,TMCB_RESPONSE_OUT|TMCB_E2EACK_IN) )
			|| (is_local(p_cell)&&has_tran_tmcbs(p_cell,TMCB_LOCAL_COMPLETED))
		)) {
			if (parse_headers(p_msg, HDR_TO, 0)==-1) {
				LOG(L_ERR, "ERROR: t_reply_matching: to parsing failed\n");
			}
		}
		if (!is_local(p_cell)) {
			run_trans_callbacks( TMCB_RESPONSE_IN, T, T->uas.request, p_msg,
				p_msg->REPLY_STATUS);
		}
		return 1;
	} /* for cycle */

	/* nothing found */
	UNLOCK_HASH(hash_index);
	DBG("DEBUG: t_reply_matching: no matching transaction exists\n");

nomatch2:
	DBG("DEBUG: t_reply_matching: failure to match a transaction\n");
	*p_branch = -1;
	set_t(0);
	return -1;
}




/* Determine current transaction
 *
 *                   Found      Not Found     Error (e.g. parsing)
 *  Return Value     1          0             -1
 *  T                ptr        0             T_UNDEFINED
 */
int t_check( struct sip_msg* p_msg , int *param_branch )
{
	int local_branch;

	/* is T still up-to-date ? */
	DBG("DEBUG: t_check: msg id=%d global id=%d T start=%p\n", 
		p_msg->id,global_msg_id,T);
	if ( p_msg->id != global_msg_id || T==T_UNDEFINED )
	{
		global_msg_id = p_msg->id;
		T = T_UNDEFINED;
		/* transaction lookup */
		if ( p_msg->first_line.type==SIP_REQUEST ) {
			/* force parsing all the needed headers*/
			if (parse_headers(p_msg, HDR_EOH, 0 )==-1) {
				LOG(L_ERR, "ERROR: t_check: parsing error\n");
				return -1;
			}