receive.c

/*
 * Copyright (C) 2010-2014 OpenSIPS Solutions
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of opensips, a free SIP server.
 *
 * opensips 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
 *
 * opensips 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 *
 * History:
 * ---------
 * 2003-02-28 scratchpad compatibility abandoned (jiri)
 * 2003-01-29 transport-independent message zero-termination in
 *            receive_msg (jiri)
 * 2003-02-07 undoed jiri's zero term. changes (they break tcp) (andrei)
 * 2003-02-10 moved zero-term in the calling functions (udp_receive &
 *            tcp_read_req)
 * 2003-08-13 fixed exec_pre_cb returning 0 (backported from stable) (andrei)
 * 2004-02-06 added user preferences support - destroy_avps() (bogdan)
 * 2004-04-30 exec_pre_cb is called after basic sanity checks (at least one
 *            via present & parsed ok)  (andrei)
 * 2004-08-23 avp core changed - destroy_avp-> reset_avps (bogdan)
 * 2005-07-26 default onreply route added (andrei)
 * 2006-12-22 functions for script flags added (bogdan)
 */

/*!
 * \file
 * \brief Receive message and process routing for it
 */


#include <string.h>
#include <stdlib.h>
#include <sys/time.h>

#include "receive.h"
#include "globals.h"
#include "dprint.h"
#include "route.h"
#include "parser/msg_parser.h"
#include "forward.h"
#include "action.h"
#include "mem/mem.h"
#include "ip_addr.h"
#include "script_cb.h"
#include "dset.h"
#include "usr_avp.h"
#include "core_stats.h"
#include "ut.h"
#include "context.h"


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

static unsigned int msg_no=0;
/* address preset vars */
str * const default_global_address=&STR_NULL;
str * const default_global_port=&STR_NULL;
str * const default_via_address=&STR_NULL;
str * const default_via_port=&STR_NULL;


unsigned int get_next_msg_no(void)
{
	return ++msg_no;
}


#define prepare_context( _ctx, _err ) \
	do { \
		if (_ctx==NULL) { \
			_ctx = context_alloc(CONTEXT_GLOBAL);\
			if (_ctx==NULL) { \
				LM_ERR("failed to allocated new context, skipping\n"); \
				goto _err; \
			} \
		} \
		memset( _ctx, 0, context_size(CONTEXT_GLOBAL)); \
	}while(0)


/*! \note WARNING: buf must be 0 terminated (buf[len]=0) or some things might
 * break (e.g.: modules/textops)
 */
int receive_msg(char* buf, unsigned int len, struct receive_info* rcv_info,
		context_p existing_context, unsigned int msg_flags)
{
	#define reset_global_context() \
		do {\
			if (!current_processing_ctx) { \
				ctx = NULL; \
			} else { \
				context_destroy(CONTEXT_GLOBAL, ctx); \
				set_global_context(NULL); \
			} \
		} while (0)
	static context_p ctx = NULL;

	struct sip_msg* msg;
	struct timeval start;
	int rc, old_route_type;
	char *tmp;
	str in_buff;

	in_buff.len = len;
	in_buff.s = buf;

	if (existing_context) {
		context_free(ctx);
		ctx = existing_context;
	}

	/* the raw processing callbacks can change the buffer,
	further use in_buff.s and at the end try to free in_buff.s
	if changed by callbacks */
	if (run_pre_raw_processing_cb(PRE_RAW_PROCESSING,&in_buff,NULL)<0) {
		LM_ERR("error in running pre raw callbacks, dropping\n");
		goto error;
	}
	/* update the length for further processing */
	len = in_buff.len;

	msg=pkg_malloc(sizeof(struct sip_msg));
	if (msg==0) {
		LM_ERR("no pkg mem left for sip_msg\n");
		goto error;
	}
	msg_no++;
	/* number of vias parsed -- good for diagnostic info in replies */
	via_cnt=0;

	memset(msg,0, sizeof(struct sip_msg)); /* init everything to 0 */
	/* fill in msg */
	msg->buf=in_buff.s;
	msg->len=len;
	msg->rcv=*rcv_info;
	msg->id=msg_no;
	msg->msg_flags=msg_flags;
	msg->ruri_q = Q_UNSPECIFIED;

	if (parse_msg(in_buff.s,len, msg)!=0){
		tmp=ip_addr2a(&(rcv_info->src_ip));
		LM_ERR("Unable to parse msg received from [%s:%d]\n",
			tmp, rcv_info->src_port);
		/* if a REQUEST msg was detected (first line was successfully parsed)
		   we should trigger the error route */
		if ( msg->first_line.type==SIP_REQUEST && sroutes->error.a!=NULL ) {
			if (existing_context == NULL)
				prepare_context( ctx, parse_error );
			set_global_context(ctx);
			run_error_route(msg, 1);
			reset_global_context();
		}
		goto parse_error;
	}
	LM_DBG("After parse_msg...\n");

	start_expire_timer(start,execmsgthreshold);
	/* jumpt to parse_error_reset (not to parse_error) while
	 * start_expire_timer() is still on */

	/* ... clear branches from previous message */
	clear_branches();

	if (msg->first_line.type==SIP_REQUEST) {
		update_stat( rcv_reqs, 1);
		/* sanity checks */
		if ((msg->via1==0) || (msg->via1->error!=PARSE_OK)){
			/* no via, send back error ? */
			LM_ERR("no via found in request\n");
			update_stat( err_reqs, 1);
			goto parse_error_reset;
		}
		/* check if necessary to add receive?->moved to forward_req */

		/* should we reuse this connection for the opposite direction? */
		if (is_tcp_based_proto(rcv_info->proto)
		    && tcpconn_add_alias(msg, rcv_info->proto_reserved1,
			                     msg->via1->port, rcv_info->proto) != 0) {
			LM_WARN("tcp alias failed\n");
			/* continue */
		}

		LM_DBG("preparing to run routing scripts...\n");
		/* set request route type --bogdan*/
		set_route_type( REQUEST_ROUTE );

		/* prepare and set a new processing context for this request only if
		 * no context was set from the upper layers */
		if (existing_context == NULL)
			prepare_context( ctx, parse_error_reset );
		set_global_context(ctx);

		/* execute pre-script callbacks, if any;
		 * if some of the callbacks said not to continue with
		 * script processing, don't do so;
		 * if we are here basic sanity checks are already done
		 * (like presence of at least one via), so you can count
		 * on via1 being parsed in a pre-script callback --andrei
		 */
		rc = exec_pre_req_cb(msg);
		if (rc == SCB_DROP_MSG) {
			update_stat( drp_reqs, 1);
			goto end; /* drop the message */
		}

		/* exec the routing script */
		if (rc & SCB_RUN_TOP_ROUTE)
			/* run the main request route and skip post_script callbacks
			 * if the TOBE_CONTINUE flag is returned */
			if ( run_top_route(sroutes->request[DEFAULT_RT], msg) &
			ACT_FL_TBCONT )
				goto end;

		/* execute post request-script callbacks */
		if (rc & SCB_RUN_POST_CBS)
			exec_post_req_cb(msg);

	} else if (msg->first_line.type==SIP_REPLY) {
		update_stat( rcv_rpls, 1);
		/* sanity checks */
		if ((msg->via1==0) || (msg->via1->error!=PARSE_OK)){
			/* no via, send back error ? */
			LM_ERR("no via found in reply\n");
			update_stat( err_rpls, 1);
			goto parse_error_reset;
		}

		/* set reply route type --bogdan*/
		set_route_type( ONREPLY_ROUTE );

		/* prepare and set a new processing context for this reply only if
		 * no context was set from the upper layers */
		if (existing_context == NULL)
			prepare_context( ctx, parse_error_reset );
		set_global_context(ctx);

		/* execute pre-script callbacks, if any ;
		 * if some of the callbacks said not to continue with
		 * script processing, don't do so ;
		 * if we are here, basic sanity checks are already done
		 * (like presence of at least one via), so you can count
		 * on via1 being parsed in a pre-script callback --andrei
		 */
		rc = exec_pre_rpl_cb(msg);
		if (rc == SCB_DROP_MSG) {
			update_stat( drp_rpls, 1);
			goto end; /* drop the reply */
		}

		swap_route_type(old_route_type, ONREPLY_ROUTE);
		/* exec the onreply routing script */
		if (rc & SCB_RUN_TOP_ROUTE && sroutes->onreply[DEFAULT_RT].a &&
		    (run_top_route(sroutes->onreply[DEFAULT_RT],msg) & ACT_FL_DROP)
		    && msg->REPLY_STATUS < 200) {
			set_route_type(old_route_type);

			LM_DBG("dropping provisional reply %d\n", msg->REPLY_STATUS);
			update_stat( drp_rpls, 1);
			goto end; /* drop the message */
		} else {
			set_route_type(old_route_type);
			/* send the msg */
			forward_reply(msg);
			/* TODO - TX reply stat */
		}

		/* execute post reply-script callbacks */
		if (rc & SCB_RUN_POST_CBS)
			exec_post_rpl_cb(msg);
	}

end:
	reset_global_context();

	__stop_expire_timer( start, execmsgthreshold, "msg processing",
		msg->buf, msg->len, 0, slow_msgs);
	reset_longest_action_list(execmsgthreshold);

	/* free possible loaded avps -bogdan */
	reset_avps();
	LM_DBG("cleaning up\n");
	free_sip_msg(msg);
	pkg_free(msg);
	if (in_buff.s != buf)
		pkg_free(in_buff.s);
	return 0;
parse_error_reset:
	reset_longest_action_list(execmsgthreshold);
parse_error:
	exec_parse_err_cb(msg);
	free_sip_msg(msg);
	pkg_free(msg);
error:
	if (in_buff.s != buf)
		pkg_free(in_buff.s);
	return -1;
}