Function get_out_socket

forward.c:93–134

! \brief return a socket_info_pointer to the sending socket * \note As opposed to * get_send_socket(), which returns process's default socket, get_out_socket * attempts to determine the outbound interface which will be used; * it creates a temporary connected socket to determine it; it will * be very likely noticeably slower, but it can deal better with * multihomed hosts */

 * multihomed hosts
 */
const struct socket_info* get_out_socket(const union sockaddr_union* to, int proto)
{
	int temp_sock;
	socklen_t len;
	union sockaddr_union from;
	const struct socket_info* si;
	struct ip_addr ip, ip_dst;

	if (proto!=PROTO_UDP) {
		LM_CRIT("can only be called for UDP\n");
		return 0;
	}

	temp_sock=socket(to->s.sa_family, SOCK_DGRAM, 0 );
	if (temp_sock==-1) {
		LM_ERR("socket() failed: %s\n", strerror(errno));
		return 0;
	}
	if (connect(temp_sock, &to->s, sockaddru_len(*to))==-1) {
		LM_ERR("connect failed: %s\n", strerror(errno));
		goto error;
	}
	len=sizeof(from);
	if (getsockname(temp_sock, &from.s, &len)==-1) {
		LM_ERR("getsockname failed: %s\n", strerror(errno));
		goto error;
	}
	su2ip_addr(&ip, &from);
	si=find_si(&ip, 0, proto);
	if (si==0) {
		LM_ERR("outbound IP %s not found as listener\n", ip_addr2a(&ip));
		goto error;
	}
	close(temp_sock);
	LM_DBG("socket determined: %p\n", si );
	return si;
error:
	su2ip_addr( &ip_dst, to);
	LM_ERR("failed to find route to %s\n", ip_addr2a(&ip_dst));
	close(temp_sock);
	return 0;
}