/*
 * $Id: t_fwd.c,v 1.61 2004/11/09 15:15:12 andrei Exp $
 *
 *
 * 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:
 * -------
 *  2003-02-13  proto support added (andrei)
 *  2003-02-24  s/T_NULL/T_NULL_CELL/ to avoid redefinition conflict w/
 *              nameser_compat.h (andrei)
 *  2003-03-01  kr set through a function now (jiri)
 *  2003-03-06  callbacks renamed; "blind UAC" introduced, which makes
 *              transaction behave as if it was forwarded even if it was
 *              not -- good for local UAS, like VM (jiri)
 *  2003-03-19  replaced all the mallocs/frees w/ pkg_malloc/pkg_free (andrei)
 *  2003-03-30  we now watch downstream delivery and if it fails, send an
 *              error message upstream (jiri)
 *  2003-04-14  use protocol from uri (jiri)
 *  2003-12-04  global TM callbacks switched to per transaction callbacks
 *              (bogdan)
 *  2004-02-13: t->is_invite and t->local replaced with flags (bogdan)
 */

#include "defs.h"


#include "../../dprint.h"
#include "../../config.h"
#include "../../parser/parser_f.h"
#include "../../ut.h"
#include "../../timer.h"
#include "../../hash_func.h"
#include "../../globals.h"
#include "../../mem/mem.h"
#include "../../dset.h"
#include "t_funcs.h"
#include "t_hooks.h"
#include "t_msgbuilder.h"
#include "ut.h"
#include "t_cancel.h"
#include "t_lookup.h"
#include "t_fwd.h"
#include "fix_lumps.h"
#include "config.h"


char *print_uac_request( struct cell *t, struct sip_msg *i_req,
	int branch, str *uri, unsigned int *len, struct socket_info *send_sock,
	enum sip_protos proto )
{
	char *buf, *shbuf;

	shbuf=0;

	/* ... we calculate branch ... */	
	if (!t_calc_branch(t, branch, i_req->add_to_branch_s,
			&i_req->add_to_branch_len ))
	{
		LOG(L_ERR, "ERROR: print_uac_request: branch computation failed\n");
		goto error01;
	}

	/* ... update uri ... */
	i_req->new_uri=*uri;

	/* run the specific callbacks for this transaction */
	run_trans_callbacks( TMCB_REQUEST_FWDED , t, i_req, 0, -i_req->REQ_METHOD);

	/* ... and build it now */
	buf=build_req_buf_from_sip_req( i_req, len, send_sock, proto );
#ifdef DBG_MSG_QA
	if (buf[*len-1]==0) {
		LOG(L_ERR, "ERROR: print_uac_request: sanity check failed\n");
		abort();
	}
#endif
	if (!buf) {
		LOG(L_ERR, "ERROR: print_uac_request: no pkg_mem\n"); 
		ser_error=E_OUT_OF_MEM;
		goto error01;
	}
	/*	clean Via's we created now -- they would accumulate for
		other branches  and for  shmem i_req they would mix up
	 	shmem with pkg_mem
	*/
	free_via_clen_lump(&i_req->add_rm);

	shbuf=(char *)shm_malloc(*len);
	if (!shbuf) {
		ser_error=E_OUT_OF_MEM;
		LOG(L_ERR, "ERROR: print_uac_request: no shmem\n");
		goto error02;
	}
	memcpy( shbuf, buf, *len );

error02:
	pkg_free( buf );
error01:
	return shbuf;
}

/* introduce a new uac, which is blind -- it only creates the
   data structures and starts FR timer, but that's it; it does
   not print messages and send anything anywhere; that is good
   for FIFO apps -- the transaction must look operationally
   and FR must be ticking, whereas the request is "forwarded"
   using a non-SIP way and will be replied the same way
*/
int add_blind_uac( /*struct cell *t*/ )
{
	unsigned short branch;
	struct cell *t;

	t=get_t();
	if (t==T_UNDEFINED || !t ) {
		LOG(L_ERR, "ERROR: add_blind_uac: no transaction context\n");
		return -1;
	}

	branch=t->nr_of_outgoings;	
	if (branch==MAX_BRANCHES) {
		LOG(L_ERR, "ERROR: add_blind_uac: "
			"maximum number of branches exceeded\n");
		return -1;
	}
	/* make sure it will be replied */
	t->flags |= T_NOISY_CTIMER_FLAG;
	t->nr_of_outgoings++;
	/* start FR timer -- protocol set by default to PROTO_NONE,
       which means retransmission timer will not be started
    */
	start_retr(&t->uac[branch].request);
	/* we are on a timer -- don't need to put on wait on script
	   clean-up	
	*/
	set_kr(REQ_FWDED); 

	return 1; /* success */
}

/* introduce a new uac to transaction; returns its branch id (>=0)
   or error (<0); it doesn't send a message yet -- a reply to it
   might interfere with the processes of adding multiple branches
*/
int add_uac( struct cell *t, struct sip_msg *request, str *uri, str* next_hop,
	struct proxy_l *proxy, int proto )
{

	int ret;
	short temp_proxy;
	union sockaddr_union to;
	unsigned short branch;
	struct socket_info* send_sock;
	char *shbuf;
	unsigned int len;

	branch=t->nr_of_outgoings;
	if (branch==MAX_BRANCHES) {
		LOG(L_ERR, "ERROR: add_uac: maximum number of branches exceeded\n");
		ret=E_CFG;
		goto error;
	}

	/* check existing buffer -- rewriting should never occur */
	if (t->uac[branch].request.buffer) {
		LOG(L_CRIT, "ERROR: add_uac: buffer rewrite attempt\n");
		ret=ser_error=E_BUG;
		goto error;
	}

	/* check DNS resolution */
	if (proxy){
		temp_proxy=0;
		proto=get_proto(proto, proxy->proto);
	}else {
		proxy=uri2proxy( next_hop ? next_hop : uri, proto );
		if (proxy==0)  {
			ret=E_BAD_ADDRESS;
			goto error;
		}
		proto=proxy->proto; /* uri2proxy will fix it for us */
		temp_proxy=1;
	}

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

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

	send_sock=get_send_socket( request, &to , proto);
	if (send_sock==0) {
		LOG(L_ERR, "ERROR: add_uac: can't fwd to af %d, proto %d "
			" (no corresponding listening socket)\n",
			to.s.sa_family, proto );
		ret=ser_error=E_NO_SOCKET;
		goto error01;
	}

	/* now message printing starts ... */
	shbuf=print_uac_request( t, request, branch, uri, 
		&len, send_sock, proto );
	if (!shbuf) {
		ret=ser_error=E_OUT_OF_MEM;
		goto error01;
	}

	/* things went well, move ahead and install new buffer! */
	t->uac[branch].request.dst.to=to;
	t->uac[branch].request.dst.send_sock=send_sock;
	t->uac[branch].request.dst.proto=proto;
	t->uac[branch].request.dst.proto_reserved1=0;
	t->uac[branch].request.buffer=shbuf;
	t->uac[branch].request.buffer_len=len;
	t->uac[branch].uri.s=t->uac[branch].request.buffer+
		request->first_line.u.request.method.len+1;
	t->uac[branch].uri.len=uri->len;
	t->nr_of_outgoings++;

	/* update stats */
	proxy->tx++;
	proxy->tx_bytes+=len;

	/* done! */	
	ret=branch;
		
error01:
	if (temp_proxy) {
		free_proxy( proxy );
		pkg_free( proxy );
	}
error:
	return ret;
}

int e2e_cancel_branch( struct sip_msg *cancel_msg, struct cell *t_cancel, 
	struct cell *t_invite, int branch )
{
	int ret;
	char *shbuf;
	unsigned int len;

	if (t_cancel->uac[branch].request.buffer) {
		LOG(L_CRIT, "ERROR: e2e_cancel_branch: buffer rewrite attempt\n");
		ret=ser_error=E_BUG;
		goto error;
	}	

	/* note -- there is a gap in proxy stats -- we don't update 
	   proxy stats with CANCEL (proxy->ok, proxy->tx, etc.)
	*/

	/* print */
	shbuf=print_uac_request( t_cancel, cancel_msg, branch, 
		&t_invite->uac[branch].uri, &len, 
		t_invite->uac[branch].request.dst.send_sock,
		t_invite->uac[branch].request.dst.proto);
	if (!shbuf) {
		LOG(L_ERR, "ERROR: e2e_cancel_branch: printing e2e cancel failed\n");
		ret=ser_error=E_OUT_OF_MEM;
		goto error;
	}
	
	/* install buffer */
	t_cancel->uac[branch].request.dst=t_invite->uac[branch].request.dst;
	t_cancel->uac[branch].request.buffer=shbuf;
	t_cancel->uac[branch].request.buffer_len=len;
	t_cancel->uac[branch].uri.s=t_cancel->uac[branch].request.buffer+
		cancel_msg->first_line.u.request.method.len+1;
	t_cancel->uac[branch].uri.len=t_invite->uac[branch].uri.len;
	

	/* success */
	ret=1;


error:
	return ret;
}

void e2e_cancel( struct sip_msg *cancel_msg, 
	struct cell *t_cancel, struct cell *t_invite )
{
	branch_bm_t cancel_bm;
	int i;
	int lowest_error;
	str backup_uri;
	int ret;

	cancel_bm=0;
	lowest_error=0;

	backup_uri=cancel_msg->new_uri;
	/* determine which branches to cancel ... */
	which_cancel( t_invite, &cancel_bm );
	t_cancel->nr_of_outgoings=t_invite->nr_of_outgoings;
	/* fix label -- it must be same for reply matching */
	t_cancel->label=t_invite->label;
	/* ... and install CANCEL UACs */
	for (i=0; i<t_invite->nr_of_outgoings; i++)
		if (cancel_bm & (1<<i)) {
			ret=e2e_cancel_branch(cancel_msg, t_cancel, t_invite, i);
			if (ret<0) cancel_bm &= ~(1<<i);
			if (ret<lowest_error) lowest_error=ret;
		}
	cancel_msg->new_uri=backup_uri;

	/* send them out */
	for (i=0; i<t_cancel->nr_of_outgoings; i++) {
		if (cancel_bm & (1<<i)) {
			if (SEND_BUFFER( &t_cancel->uac[i].request)==-1) {
				LOG(L_ERR, "ERROR: e2e_cancel: send failed\n");
			}
			start_retr( &t_cancel->uac[i].request );
		}
	}


	/* if error occurred, let it know upstream (final reply
	   will also move the transaction on wait state
	*/
	if (lowest_error<0) {
		LOG(L_ERR, "ERROR: cancel error\n");
		t_reply( t_cancel, cancel_msg, 500, "cancel error");
	/* if there are pending branches, let upstream know we
	   are working on it
	*/
	} else if (cancel_bm) {
		DBG("DEBUG: e2e_cancel: e2e cancel proceeding\n");
		t_reply( t_cancel, cancel_msg, 200, CANCELING );
	/* if the transaction exists, but there is no more pending
	   branch, tell upstream we're done
	*/
	} else {
		DBG("DEBUG: e2e_cancel: e2e cancel -- no more pending branches\n");
		t_reply( t_cancel, cancel_msg, 200, CANCEL_DONE );
	}

#ifdef LOCAL_487

	/* local 487s have been deprecated -- it better handles
	 * race conditions (UAS sending 200); hopefully there are
	 * no longer UACs who go crazy waiting for the 487 whose
	 * forwarding is being blocked by other unresponsive branch
	 */

	/* we could await downstream UAS's 487 replies; however,
	   if some of the branches does not do that, we could wait
	   long time and annoy upstream UAC which wants to see 
	   a result of CANCEL quickly
	*/
	DBG("DEBUG: e2e_cancel: sending 487\n");
	/* in case that something in the meantime has been sent upstream
	   (like if FR hit at the same time), don't try to send */
	if (t_invite->uas.status>=200) return;
	/* there is still a race-condition -- the FR can hit now; that's
	   not too bad -- we take care in t_reply's REPLY_LOCK; in
	   the worst case, both this t_reply and other replier will
	   try, and the later one will result in error message 
	   "can't reply twice"
	*/
	t_reply(t_invite, t_invite->uas.request, 487, CANCELED );
#endif
}


/* function returns:
 *       1 - forward successful
 *      -1 - error during forward
 */
int t_forward_nonack( struct cell *t, struct sip_msg* p_msg , 
	struct proxy_l * proxy, int proto)
{
	str          backup_uri;
	int branch_ret, lowest_ret;
	str current_uri;
	branch_bm_t	added_branches;
	int first_branch;
	int i, q;
	struct cell *t_invite;
	int success_branch;
	int try_new;
	str dst_uri;

	/* make -Wall happy */
	current_uri.s=0;

	set_kr(REQ_FWDED);

	if (p_msg->REQ_METHOD==METHOD_CANCEL) {
		t_invite=t_lookupOriginalT(  p_msg );
		if (t_invite!=T_NULL_CELL) {
			e2e_cancel( p_msg, t, t_invite );
			UNREF(t_invite);
			return 1;
		}
	}

	/* backup current uri ... add_uac changes it */
	backup_uri = p_msg->new_uri;
	/* if no more specific error code is known, use this */
	lowest_ret=E_BUG;
	/* branches added */
	added_branches=0;
	/* branch to begin with */
	first_branch=t->nr_of_outgoings;

	/* on first-time forwarding, use current uri, later only what
	   is in additional branches (which may be continuously refilled
	*/
	if (first_branch==0) {
		try_new=1;
		branch_ret=add_uac( t, p_msg, GET_RURI(p_msg), GET_NEXT_HOP(p_msg), proxy, proto );
		if (branch_ret>=0) 
			added_branches |= 1<<branch_ret;
		else
			lowest_ret=branch_ret;
	} else try_new=0;

	init_branch_iterator();
	while((current_uri.s=next_branch( &current_uri.len, &q, &dst_uri.s, &dst_uri.len))) {
		try_new++;
		branch_ret=add_uac( t, p_msg, &current_uri, 
				    (dst_uri.len) ? (&dst_uri) : &current_uri, 
				    proxy, proto);
		/* pick some of the errors in case things go wrong;
		   note that picking lowest error is just as good as
		   any other algorithm which picks any other negative
		   branch result */
		if (branch_ret>=0) 
			added_branches |= 1<<branch_ret;
		else
			lowest_ret=branch_ret;
	}
	/* consume processed branches */
	clear_branches();

	/* restore original URI */
	p_msg->new_uri=backup_uri;

	/* don't forget to clear all branches processed so far */

	/* things went wrong ... no new branch has been fwd-ed at all */
	if (added_branches==0) {
		if (try_new==0) {
			LOG(L_ERR, "ERROR: t_forward_nonack: no branched for forwarding\n");
			return -1;
		}
		LOG(L_ERR, "ERROR: t_forward_nonack: failure to add branches\n");
		return lowest_ret;
	}

	/* send them out now */
	success_branch=0;
	for (i=first_branch; i<t->nr_of_outgoings; i++) {
		if (added_branches & (1<<i)) {
			if (SEND_BUFFER( &t->uac[i].request)==-1) {
				LOG(L_ERR, "ERROR: t_forward_nonack: sending request failed\n");
				if (proxy) { proxy->errors++; proxy->ok=0; }
			} else {
				success_branch++;
			}
			start_retr( &t->uac[i].request );
		}
	}
	if (success_branch<=0) {
		ser_error=E_SEND;
		return -1;
	}
	return 1;
}	

int t_replicate(struct sip_msg *p_msg,  struct proxy_l *proxy, int proto )
{
	/* this is a quite horrible hack -- we just take the message
	   as is, including Route-s, Record-route-s, and Vias ,
	   forward it downstream and prevent replies received
	   from relaying by setting the replication/local_trans bit;

		nevertheless, it should be good enough for the primary
		customer of this function, REGISTER replication

		if we want later to make it thoroughly, we need to
		introduce delete lumps for all the header fields above
	*/
	return t_relay_to(p_msg, proxy, proto, 1 /* replicate */);
}
