/*
  * $Id$

  *
  * Copyright (C) 2001-2003 Fhg Fokus
  *
  * This file is part of ser, a free SIP server.
  *
  * ser 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
  *
  * For a license to use the ser software under conditions
  * other than those described here, or to purchase support for this
  * software, please contact iptel.org by e-mail at the following addresses:
  *    info@iptel.org
  *
  * ser 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  *
  * History:
  * -------

  * 2003-01-23 support for determination of outbound interface added :

  *            get_out_socket (jiri)

  * 2003-01-24 reply to rport support added, contributed by
  *             Maxim Sobolev <sobomax@FreeBSD.org> and modified by andrei

  *

  */
 
 

 #include <string.h>

 #include <stdio.h>
 #include <stdlib.h>

 #include <sys/types.h>
 #include <sys/socket.h>

 #include <netdb.h>
 #include <netinet/in.h>

 #include <arpa/inet.h>

 
 #include "forward.h"

 #include "hash_func.h"

 #include "config.h"

 #include "parser/msg_parser.h"

 #include "route.h"
 #include "dprint.h"

 #include "udp_server.h"

 #include "globals.h"

 #include "data_lump.h"

 #include "ut.h"

 #include "mem/mem.h"

 #include "msg_translator.h"

 #include "sr_module.h"

 #include "stats.h"

 #include "ip_addr.h"
 #include "resolve.h"

 #include "name_alias.h"

 #ifdef USE_TCP
 #include "tcp_server.h"
 #endif

 #ifdef DEBUG_DMALLOC
 #include <dmalloc.h>
 #endif
 

 /* return a socket_info_pointer to the sending socket; 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
  */
 struct socket_info* get_out_socket(union sockaddr_union* to, int proto)
 {
 	int temp_sock;
 	socklen_t len;
 	int r;
 	union sockaddr_union from; 
 
 	if (proto!=PROTO_UDP) {
 		LOG(L_CRIT, "BUG: get_out_socket can only be called for UDP\n");
 		return 0;
 	}
 
 	r=-1;
 	temp_sock=socket(to->s.sa_family, SOCK_DGRAM, 0 );
 	if (temp_sock==-1) {
 		LOG(L_ERR, "ERROR: get_out_socket: socket() failed: %s\n",
 				strerror(errno));
 		return 0;
 	}
 	if (connect(temp_sock, &to->s, sockaddru_len(*to))==-1) {
 		LOG(L_ERR, "ERROR: get_out_socket: connect failed: %s\n",
 				strerror(errno));
 		goto error;
 	}
 	len=sockaddru_len(from);
 	if (getsockname(temp_sock, &from.s, &len)==-1) {
 		LOG(L_ERR, "ERROR: get_out_socket: getsockname failed: %s\n",
 				strerror(errno));
 		goto error;
 	}
 	for (r=0; r<sock_no; r++) {
 		switch(from.s.sa_family) {
 			case AF_INET:	
 						if (sock_info[r].address.af!=AF_INET)
 								continue;
 						if (memcmp(&sock_info[r].address.u,
 								&from.sin.sin_addr, 
 								sock_info[r].address.len)==0)
 							goto error; /* it is actually success */
 						break;
 			case AF_INET6:	
 						if (sock_info[r].address.af!=AF_INET6)
 								continue;
 						if (memcmp(&sock_info[r].address.u,
 								&from.sin6.sin6_addr, len)==0)
 							goto error;
 						continue;
 			default:	LOG(L_ERR, "ERROR: get_out_socket: "
 									"unknown family: %d\n",
 									from.s.sa_family);
 						r=-1;
 						goto error;
 		}
 	}
 	LOG(L_ERR, "ERROR: get_out_socket: no socket found\n");
 	r=-1;
 error:
 	close(temp_sock);
 	DBG("DEBUG: get_out_socket: socket determined: %d\n", r );
 	return r==-1? 0: &sock_info[r];
 }
 

 /* returns a socket_info pointer to the sending socket or 0 on error

  * params: destination socket_union pointer

  */

 struct socket_info* get_send_socket(union sockaddr_union* to, int proto)

 {
 	struct socket_info* send_sock;

 
 	if (mhomed && proto==PROTO_UDP) return get_out_socket(to, proto);
 

 	send_sock=0;
 	/* check if we need to change the socket (different address families -
 	 * eg: ipv4 -> ipv6 or ipv6 -> ipv4) */

 #ifdef USE_TCP
 	if (proto==PROTO_TCP){
 		/* on tcp just use the "main address", we don't really now the

 		 * sending address (we can find it out, but we'll need also to see

 		 * if we listen on it, and if yes on which port -> too complicated*/
 		switch(to->s.sa_family){
 			case AF_INET:	send_sock=sendipv4_tcp;
 							break;
 #ifdef USE_IPV6
 			case AF_INET6:	send_sock=sendipv6_tcp;
 							break;
 #endif
 			default:		LOG(L_ERR, "get_send_socket: BUG: don't know how"
 									" to forward to af %d\n", to->s.sa_family);
 		}
 	}else
 #endif
 	      if ((bind_address==0) ||(to->s.sa_family!=bind_address->address.af)){

 		switch(to->s.sa_family){
 			case AF_INET:	send_sock=sendipv4;
 							break;
 #ifdef USE_IPV6
 			case AF_INET6:	send_sock=sendipv6;
 							break;
 #endif
 			default:		LOG(L_ERR, "get_send_socket: BUG: don't know how"
 									" to forward to af %d\n", to->s.sa_family);
 		}
 	}else send_sock=bind_address;
 	return send_sock;
 }
 
 
 

 /* checks if the host:port is one of the address we listen on;
  * if port==0, the  port number is ignored
  * returns 1 if true, 0 if false, -1 on error

 */

 int check_self(str* host, unsigned short port)

 {
 	int r;
 	
 	for (r=0; r<sock_no; r++){
 		DBG("check_self - checking if host==us: %d==%d && "
 				" [%.*s] == [%.*s]\n", 
 					host->len,
 					sock_info[r].name.len,
 					host->len, host->s,
 					sock_info[r].name.len, sock_info[r].name.s
 			);

 		if  ((port)&&(sock_info[r].port_no!=port)) continue;

 		if ( (host->len==sock_info[r].name.len) && 
 	#ifdef USE_IPV6
 			(strncasecmp(host->s, sock_info[r].name.s,
 								 sock_info[r].name.len)==0) /*slower*/
 	#else
 			(memcmp(host->s, sock_info[r].name.s, 
 								sock_info[r].name.len)==0)
 	#endif
 			)
 			break;
 	/* check if host == ip address */
 		if ( 	(!sock_info[r].is_ip) &&
 				(host->len==sock_info[r].address_str.len) && 
 	#ifdef USE_IPV6
 			(strncasecmp(host->s, sock_info[r].address_str.s,
 								 sock_info[r].address_str.len)==0) /*slower*/
 	#else
 			(memcmp(host->s, sock_info[r].address_str.s, 
 								sock_info[r].address_str.len)==0)
 	#endif
 			)
 			break;
 	}
 	if (r==sock_no){

 		/* try to look into the aliases*/

 		if (grep_aliases(host->s, host->len, port)==0){

 			DBG("check_self: host != me\n");
 			return 0;
 		}

 	}
 	return 1;
 }
 
 

 int forward_request( struct sip_msg* msg, struct proxy_l * p, int proto)

 {

 	unsigned int len;

 	char* buf;

 	union sockaddr_union* to;

 	struct socket_info* send_sock;

 	char md5[MD5_LEN];

 	int id; /* used as branch for tcp! */

 	to=0;

 	buf=0;

 	id=0;

 	to=(union sockaddr_union*)malloc(sizeof(union sockaddr_union));

 	if (to==0){

 		ser_error=E_OUT_OF_MEM;

 		LOG(L_ERR, "ERROR: forward_request: out of memory\n");

 		goto error;
 	}

 	/* if error try next ip address if possible */

 	if (p->ok==0){
 		if (p->host.h_addr_list[p->addr_idx+1])
 			p->addr_idx++;

 		else p->addr_idx=0;

 		p->ok=1;

 	}

 	hostent2su(to, &p->host, p->addr_idx, 
 				(p->port)?htons(p->port):htons(SIP_PORT));

 	p->tx++;

 	p->tx_bytes+=len;

 	send_sock=get_send_socket(to, proto);

 	if (send_sock==0){
 		LOG(L_ERR, "forward_req: ERROR: cannot forward to af %d "
 				"no coresponding listening socket\n", to->s.sa_family);

 		ser_error=E_NO_SOCKET;

 		goto error1;

 	}

 
 	/* 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 ) {
 		*msg->add_to_branch_s='0';
 		msg->add_to_branch_len=1;
 	} else {
 		if (!char_msg_val( msg, md5 )) 	{ /* parses transaction key */
 			LOG(L_ERR, "ERROR: forward_request: char_msg_val failed\n");
 			goto error1;
 		}
 		msg->hash_index=hash( msg->callid->body, get_cseq(msg)->number);

 		if (!branch_builder( msg->hash_index, 0, md5, id /* 0-th branch */,

 					msg->add_to_branch_s, &msg->add_to_branch_len )) {
 			LOG(L_ERR, "ERROR: forward_request: branch_builder failed\n");
 			goto error1;
 		}
 	}
 

 	buf = build_req_buf_from_sip_req( msg, &len, send_sock,  proto);

 	if (!buf){

 		LOG(L_ERR, "ERROR: forward_request: building failed\n");
 		goto error1;

 	}
 	 /* send it! */

 	DBG("Sending:\n%.*s.\n", (int)len, buf);

 	DBG("orig. len=%d, new_len=%d, proto=%d\n", msg->len, len, proto );

 	
 	if (proto==PROTO_UDP){
 		if (udp_send(send_sock, buf, len,  to)==-1){
 				ser_error=E_SEND;
 				p->errors++;
 				p->ok=0;
 				STATS_TX_DROPS;
 				goto error1;
 		}
 	}
 #ifdef USE_TCP
 	 else if (proto==PROTO_TCP){

 		if (tcp_send(buf, len, to, 0)<0){

 				ser_error=E_SEND;
 				p->errors++;
 				p->ok=0;
 				STATS_TX_DROPS;
 				goto error1;
 		}
 	}
 #endif
 	 else{
 		LOG(L_CRIT, "BUG: forward_request: unknown proto %d\n", proto);
 		ser_error=E_SEND;
 		STATS_TX_DROPS;
 		goto error1;

 	}

 	/* sent requests stats */

 	STATS_TX_REQUEST(  msg->first_line.u.request.method_value );

 	pkg_free(buf);

 	free(to);

 	/* received_buf & line_buf will be freed in receive_msg by free_lump_list*/

 	return 0;

 
 error1:
 	free(to);

 error:

 	if (buf) pkg_free(buf);

 	return -1;
 }
 
 

 int update_sock_struct_from_via( union sockaddr_union* to,

 								 struct via_body* via )

 {

 	struct hostent* he;

 	str* name;

 	int err;

 	unsigned short port;

 	port=0;
 	if (via->rport && via->rport->value.s){
 		port=str2s(via->rport->value.s, via->rport->value.len, &err);
 		if (err){
 			LOG(L_NOTICE, "ERROR: forward_reply: bad rport value(%.*s)\n",
 					via->rport->value.len, via->rport->value.s);
 			port=0;
 		}
 	}

 	if (via->received){
 		DBG("update_sock_struct_from_via: using 'received'\n");
 		name=&(via->received->value);
 		/* making sure that we won't do SRV lookup on "received"
 		 * (possible if no DNS_IP_HACK is used)*/

 		if (port==0) port=via->port?via->port:SIP_PORT; 

 	}else{
 		DBG("update_sock_struct_from_via: using via host\n");
 		name=&(via->host);

 		if (port==0) port=via->port;

 	}

 	/* we do now a malloc/memcpy because gethostbyname loves \0-terminated 
 	   strings; -jiri 
 	   but only if host is not null terminated
 	   (host.s[len] will always be ok for a via)
 	    BTW: when is via->host.s non null terminated? tm copy? - andrei 
 	    Yes -- it happened on generating a 408 by TM; -jiri

 	    sip_resolvehost now accepts str -janakj

 	*/

 	DBG("update_sock_struct_from_via: trying SRV lookup\n");
 	he=sip_resolvehost(name, &port);

 	
 	if (he==0){

 		LOG(L_NOTICE, "ERROR:forward_reply:resolve_host(%.*s) failure\n",
 				name->len, name->s);

 		return -1;

 	}

 	hostent2su(to, he, 0, htons(port));

 	return 1;
 }
 

 
 /* removes first via & sends msg to the second */

 int forward_reply(struct sip_msg* msg)

 {

 	char* new_buf;

 	union sockaddr_union* to;

 	struct socket_info* send_sock;

 	unsigned int new_len;

 	struct sr_module *mod;

 	int proto;
 #ifdef USE_TCP
 	char* s;
 	int len;
 	int id;
 #endif

 	to=0;
 	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)!=1){

 			LOG(L_NOTICE, "ERROR: forward_reply: 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;
 		}
 	}

 	/* quick hack, slower for mutliple modules*/
 	for (mod=modules;mod;mod=mod->next){
 		if ((mod->exports) && (mod->exports->response_f)){
 			DBG("forward_reply: found module %s, passing reply to it\n",
 					mod->exports->name);
 			if (mod->exports->response_f(msg)==0) goto skip;
 		}
 	}

 	/* we have to forward the reply stateless, so we need second via -bogdan*/

 	if (parse_headers( msg, HDR_VIA2, 0 )==-1 
 		|| (msg->via2==0) || (msg->via2->error!=PARSE_OK))

 	{
 		/* no second via => error */
 		LOG(L_ERR, "ERROR: forward_msg: no 2nd via found in reply\n");
 		goto error;
 	}
 

 	to=(union sockaddr_union*)malloc(sizeof(union sockaddr_union));

 	if (to==0){
 		LOG(L_ERR, "ERROR: forward_reply: out of memory\n");
 		goto error;
 	}

 	new_buf = build_res_buf_from_sip_res( msg, &new_len);

 	if (!new_buf){
 		LOG(L_ERR, "ERROR: forward_reply: building failed\n");

 		goto error;
 	}

 	proto=msg->via2->proto;

 	if (update_sock_struct_from_via( to, msg->via2 )==-1) goto error;

 	send_sock=get_send_socket(to, proto);

 	if (send_sock==0){
 		LOG(L_ERR, "forward_reply: ERROR: no sending socket found\n");
 		goto error;
 	}

 	if (proto==PROTO_UDP){
 		if (udp_send(send_sock, new_buf,new_len,  to)==-1)
 		{
 			STATS_TX_DROPS;
 			goto error;
 		}
 	}
 #ifdef USE_TCP
 	 else if (proto==PROTO_TCP){
 		 id=0;

 		/* 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;
 			DBG("forward_reply: i=%.*s\n",len, s);
 			id=reverse_hex2int(s, len);
 			DBG("forward_reply: id= %x\n", id);

 		}		
 				

 		if (tcp_send(new_buf, new_len,  to, id)<0)

 		{
 			STATS_TX_DROPS;
 			goto error;
 		}
 	} 
 #endif
 	else{
 		LOG(L_CRIT, "BUG: forward_reply: unknown proto %d\n", proto);

 		goto error;

 	}

 #ifdef STATS

 		STATS_TX_RESPONSE(  (msg->first_line.u.reply.statuscode/100) );

 #endif

 	DBG(" reply forwarded to %.*s:%d\n", 
 			msg->via2->host.len, msg->via2->host.s,
 			(unsigned short) msg->via2->port);

 	pkg_free(new_buf);

 	free(to);

 skip:

 	return 0;
 error:

 	if (new_buf) pkg_free(new_buf);

 	if (to) free(to);

 	return -1;
 }