/* forwards a request to dst
* parameters:
* msg - sip msg
* dst - destination name, if non-null it will be resolved and
* send_info updated with the ip/port. Even if dst is non
* null send_info must contain the protocol and if a non
* default port or non srv. lookup is desired, the port must
* be !=0
* port - used only if dst!=0 (else the port in send_info->to is used)
* send_info - value/result partially filled dest_info structure:
* - send_info->proto and comp are used
* - send_info->to will be filled (dns)
* - send_info->send_flags is filled from the message
* - if the send_socket member is null, a send_socket will be
* chosen automatically
* WARNING: don't forget to zero-fill all the unused members (a non-zero
* random id along with proto==PROTO_TCP can have bad consequences, same for
* a bogus send_socket value)
*/
int forward_request(struct sip_msg* msg, str* dst, unsigned short port,
struct dest_info* send_info)
{
unsigned int len;
char* buf;
char md5[MD5_LEN];
struct socket_info* orig_send_sock; /* initial send_sock */
int ret;
struct ip_addr ip; /* debugging only */
char proto;
#ifdef USE_DNS_FAILOVER
struct socket_info* prev_send_sock;
int err;
struct dns_srv_handle dns_srv_h;
prev_send_sock=0;
err=0;
#endif
buf=0;
orig_send_sock=send_info->send_sock;
proto=send_info->proto;
ret=0;
if(dst){
#ifdef USE_DNS_FAILOVER
if (cfg_get(core, core_cfg, use_dns_failover)){
dns_srv_handle_init(&dns_srv_h);
err=dns_sip_resolve2su(&dns_srv_h, &send_info->to, dst, port,
&proto, dns_flags);
if (err!=0){
LOG(L_ERR, "ERROR: forward_request: resolving \"%.*s\""
" failed: %s [%d]\n", dst->len, ZSW(dst->s),
dns_strerror(err), err);
ret=E_BAD_ADDRESS;
goto error;
}
}else
#endif
if (sip_hostport2su(&send_info->to, dst, port, &proto)<0){
LOG(L_ERR, "ERROR: forward_request: bad host name %.*s,"
" dropping packet\n", dst->len, ZSW(dst->s));
ret=E_BAD_ADDRESS;
goto error;
}
}/* dst */
send_info->send_flags=msg->fwd_send_flags;
/* calculate branch for outbound request; if syn_branch is turned off,
calculate is from transaction key, i.e., as an md5 of From/To/CallID/
CSeq exactly the same way as TM does; good for reboot -- than messages
belonging to transaction lost due to reboot will still be forwarded
with the same branch parameter and will be match-able downstream
if it is turned on, we don't care about reboot; we simply put a simple
value in there; better for performance
*/
if (syn_branch ) {
memcpy(msg->add_to_branch_s, "z9hG4bKcydzigwkX", 16);
msg->add_to_branch_len=16;
} else {
if (!char_msg_val( msg, md5 )) { /* parses transaction key */
LOG(L_ERR, "ERROR: forward_request: char_msg_val failed\n");
ret=E_UNSPEC;
goto error;
}
msg->hash_index=hash( msg->callid->body, get_cseq(msg)->number);
if (!branch_builder( msg->hash_index, 0, md5, 0 /* 0-th branch */,
msg->add_to_branch_s, &msg->add_to_branch_len )) {
LOG(L_ERR, "ERROR: forward_request: branch_builder failed\n");
ret=E_UNSPEC;
goto error;
}
}
/* try to send the message until success or all the ips are exhausted
* (if dns lookup is performed && the dns cache used ) */
#ifdef USE_DNS_FAILOVER
do{
#endif
if (orig_send_sock==0) /* no forced send_sock => find it **/
send_info->send_sock=get_send_socket(msg, &send_info->to, proto);
if (send_info->send_sock==0){
LOG(L_ERR, "forward_req: ERROR: cannot forward to af %d, proto %d "
"no corresponding listening socket\n",
send_info->to.s.sa_family, proto);
ret=ser_error=E_NO_SOCKET;
#ifdef USE_DNS_FAILOVER
/* continue, maybe we find a socket for some other ip */
continue;
#else
goto error;
#endif
}
#ifdef USE_DNS_FAILOVER
if (prev_send_sock!=send_info->send_sock){
/* rebuild the message only if the send_sock changed */
prev_send_sock=send_info->send_sock;
#endif
if (buf) pkg_free(buf);
send_info->proto=proto;
buf = build_req_buf_from_sip_req(msg, &len, send_info, 0);
if (!buf){
LOG(L_ERR, "ERROR: forward_request: building failed\n");
ret=E_OUT_OF_MEM; /* most probable */
goto error;
}
#ifdef USE_DNS_FAILOVER
}
#endif
/* send it! */
DBG("Sending:\n%.*s.\n", (int)len, buf);
DBG("orig. len=%d, new_len=%d, proto=%d\n",
msg->len, len, send_info->proto );
if (run_onsend(msg, send_info, buf, len)==0){
su2ip_addr(&ip, &send_info->to);
LOG(L_INFO, "forward_request: request to %s:%d(%d) dropped"
" (onsend_route)\n", ip_addr2a(&ip),
su_getport(&send_info->to), send_info->proto);
ser_error=E_OK; /* no error */
ret=E_ADM_PROHIBITED;
#ifdef USE_DNS_FAILOVER
continue; /* try another ip */
#else
goto error; /* error ? */
#endif
}
#ifdef USE_DST_BLACKLIST
if (cfg_get(core, core_cfg, use_dst_blacklist)){
if (dst_is_blacklisted(send_info, msg)){
su2ip_addr(&ip, &send_info->to);
LOG(L_DBG, "DEBUG: blacklisted destination:%s:%d (%d)\n",
ip_addr2a(&ip), su_getport(&send_info->to),
send_info->proto);
ret=ser_error=E_SEND;
#ifdef USE_DNS_FAILOVER
continue; /* try another ip */
#else
goto error;
#endif
}
}
#endif
if (msg_send(send_info, buf, len)<0){
ret=ser_error=E_SEND;
#ifdef USE_DST_BLACKLIST
(void)dst_blacklist_add(BLST_ERR_SEND, send_info, msg);
#endif
#ifdef USE_DNS_FAILOVER
continue; /* try another ip */
#else
goto error;
#endif
}else{
ret=ser_error=E_OK;
/* sent requests stats */
STATS_TX_REQUEST( msg->first_line.u.request.method_value );
/* exit succcesfully */
goto end;
}
#ifdef USE_DNS_FAILOVER
}while(dst && cfg_get(core, core_cfg, use_dns_failover) &&
dns_srv_handle_next(&dns_srv_h, err) &&
((err=dns_sip_resolve2su(&dns_srv_h, &send_info->to, dst, port,
&proto, dns_flags))==0));
if ((err!=0) && (err!=-E_DNS_EOR)){
LOG(L_ERR, "ERROR: resolving %.*s host name in uri"
" failed: %s [%d] (dropping packet)\n",
dst->len, ZSW(dst->s),
dns_strerror(err), err);
ret=ser_error=E_BAD_ADDRESS;
goto error;
}
#endif
error:
STATS_TX_DROPS;
end:
#ifdef USE_DNS_FAILOVER
if (dst && cfg_get(core, core_cfg, use_dns_failover)){
dns_srv_handle_put(&dns_srv_h);
}
#endif
if (buf) pkg_free(buf);
/* received_buf & line_buf will be freed in receive_msg by free_lump_list*/
#if defined STATS_REQ_FWD_OK || defined STATS_REQ_FWD_DROP
if(ret==0)
STATS_REQ_FWD_OK();
else
STATS_REQ_FWD_DROP();
#endif /* STATS_REQ_FWD_* */
return ret;
}
/** removes first via & sends msg to the second
* - mode param controls if modules sip response callbacks are executed */
static int do_forward_reply(struct sip_msg* msg, int mode)
{
char* new_buf;
struct dest_info dst;
unsigned int new_len;
int r;
struct ip_addr ip;
#ifdef USE_TCP
char* s;
int len;
#endif
init_dest_info(&dst);
new_buf=0;
/*check if first via host = us */
if (check_via){
if (check_self(&msg->via1->host,
msg->via1->port?msg->via1->port:SIP_PORT,
msg->via1->proto)!=1){
LM_ERR("host in first via!=me : %.*s:%d\n",
msg->via1->host.len, msg->via1->host.s, msg->via1->port);
/* send error msg back? */
goto error;
}
}
/* check modules response_f functions */
if(likely(mode==0)) {
for (r=0; r<mod_response_cbk_no; r++)
if (mod_response_cbks[r](msg)==0) goto skip;
}
/* we have to forward the reply stateless, so we need second via -bogdan*/
if (parse_headers( msg, HDR_VIA2_F, 0 )==-1
|| (msg->via2==0) || (msg->via2->error!=PARSE_OK))
{
/* no second via => error */
LM_DBG("reply cannot be forwarded - no 2nd via\n");
goto error;
}
new_buf = build_res_buf_from_sip_res( msg, &new_len);
if (!new_buf){
LM_ERR("building failed\n");
goto error;
}
dst.proto=msg->via2->proto;
SND_FLAGS_OR(&dst.send_flags, &msg->fwd_send_flags, &msg->rpl_send_flags);
if (update_sock_struct_from_via( &dst.to, msg, msg->via2 )==-1) goto error;
#ifdef USE_COMP
dst.comp=msg->via2->comp_no;
#endif
#if defined USE_TCP || defined USE_SCTP
if (
#ifdef USE_TCP
dst.proto==PROTO_TCP
|| dst.proto==PROTO_WS
#ifdef USE_TLS
|| dst.proto==PROTO_TLS
|| dst.proto==PROTO_WSS
#endif
#ifdef USE_SCTP
||
#endif /* USE_SCTP */
#endif /* USE_TCP */
#ifdef USE_SCTP
dst.proto==PROTO_SCTP
#endif /* USE_SCTP */
){
/* find id in i param if it exists */
if (msg->via1->i && msg->via1->i->value.s){
s=msg->via1->i->value.s;
len=msg->via1->i->value.len;
LM_DBG("i=%.*s\n",len, ZSW(s));
if (reverse_hex2int(s, len, (unsigned int*)&dst.id)<0){
LM_ERR("bad via i param \"%.*s\"\n", len, ZSW(s));
dst.id=0;
}
}
}
#endif
apply_force_send_socket(&dst, msg);
/* call onsend_route */
if(dst.send_sock == NULL) {
dst.send_sock=get_send_socket(msg, &dst.to, dst.proto);
if (dst.send_sock==0){
LM_ERR("cannot forward reply\n");
goto done;
}
}
if (onsend_route_enabled(SIP_REPLY)){
if (run_onsend(msg, &dst, new_buf, new_len)==0){
su2ip_addr(&ip, &(dst.to));
LM_ERR("reply to %s:%d(%d) dropped (onsend_route)\n",
ip_addr2a(&ip), su_getport(&(dst.to)), dst.proto);
goto error; /* error ? */
}
}
if (msg_send(&dst, new_buf, new_len)<0)
{
STATS_RPL_FWD_DROP();
goto error;
}
done:
#ifdef STATS
STATS_TX_RESPONSE( (msg->first_line.u.reply.statuscode/100) );
#endif
LM_DBG("reply forwarded to %.*s:%d\n",
msg->via2->host.len, msg->via2->host.s,
(unsigned short) msg->via2->port);
STATS_RPL_FWD_OK();
pkg_free(new_buf);
skip:
return 0;
error:
if (new_buf) pkg_free(new_buf);
return -1;
}