Ticket #205: merged proxy functionalities from stable to trunk

git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@1127 74dad513-b988-da41-8d7b-12977e46ad98

3 files changed, 1355 insertions, 0 deletions

diff --git a/pjsip-apps/src/samples/proxy.h b/pjsip-apps/src/samples/proxy.h
new file mode 100644
index 00000000..5f62a503
--- /dev/null
+++ b/pjsip-apps/src/samples/proxy.h
@@ -0,0 +1,525 @@
+/* $Id$ */
+/* 
+ * Copyright (C) 2003-2007 Benny Prijono <benny@prijono.org>
+ *
+ * This program 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.
+ *
+ * This program 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 
+ */
+#include <pjsip.h>
+#include <pjlib-util.h>
+#include <pjlib.h>
+
+
+/* Options */
+static struct global_struct
+{
+    pj_caching_pool	 cp;
+    pjsip_endpoint	*endpt;
+    int			 port;
+    pj_pool_t		*pool;
+
+    pj_thread_t		*thread;
+    pj_bool_t		 quit_flag;
+
+    pj_bool_t		 record_route;
+
+    unsigned		 name_cnt;
+    pjsip_host_port	 name[16];
+} global;
+
+
+
+static void app_perror(const char *msg, pj_status_t status)
+{
+    char errmsg[PJ_ERR_MSG_SIZE];
+
+    pj_strerror(status, errmsg, sizeof(errmsg));
+    PJ_LOG(1,(THIS_FILE, "%s: %s", msg, errmsg));
+}
+
+
+static void usage(void)
+{
+    puts("Options:\n"
+	 "\n"
+	 " --port N       Set local listener port to N\n"
+	 " --rr           Perform record routing\n"
+	 " --log-level N  Set log level to N (default: 4)\n"
+	 " --help         Show this help screen\n"
+	 );
+}
+
+
+static pj_status_t init_options(int argc, char *argv[])
+{
+    struct pj_getopt_option long_opt[] = {
+	{ "port",	1, 0, 'p'},
+	{ "rr",		0, 0, 'R'},
+	{ "log-level",	1, 0, 'L'},
+	{ "help",	0, 0, 'h'},
+    };
+    int c;
+    int opt_ind;
+
+    pj_optind = 0;
+    while((c=pj_getopt_long(argc, argv, "", long_opt, &opt_ind))!=-1) {
+	switch (c) {
+	case 'p':
+	    global.port = atoi(pj_optarg);
+	    printf("Port is set to %d\n", global.pool);
+	    break;
+	
+	case 'R':
+	    global.record_route = PJ_TRUE;
+	    printf("Using record route mode\n");
+	    break;
+
+	case 'L':
+	    pj_log_set_level(atoi(pj_optarg));
+	    break;
+
+	case 'h':
+	    usage();
+	    return -1;
+
+	default:
+	    puts("Unknown option. Run with --help for help.");
+	    return -1;
+	}
+    }
+
+    return PJ_SUCCESS;
+}
+
+
+/*****************************************************************************
+ * This is a very simple PJSIP module, whose sole purpose is to display
+ * incoming and outgoing messages to log. This module will have priority
+ * higher than transport layer, which means:
+ *
+ *  - incoming messages will come to this module first before reaching
+ *    transaction layer.
+ *
+ *  - outgoing messages will come to this module last, after the message
+ *    has been 'printed' to contiguous buffer by transport layer and
+ *    appropriate transport instance has been decided for this message.
+ *
+ */
+
+/* Notification on incoming messages */
+static pj_bool_t logging_on_rx_msg(pjsip_rx_data *rdata)
+{
+    PJ_LOG(5,(THIS_FILE, "RX %d bytes %s from %s %s:%d:\n"
+			 "%.*s\n"
+			 "--end msg--",
+			 rdata->msg_info.len,
+			 pjsip_rx_data_get_info(rdata),
+			 rdata->tp_info.transport->type_name,
+			 rdata->pkt_info.src_name,
+			 rdata->pkt_info.src_port,
+			 (int)rdata->msg_info.len,
+			 rdata->msg_info.msg_buf));
+    
+    /* Always return false, otherwise messages will not get processed! */
+    return PJ_FALSE;
+}
+
+/* Notification on outgoing messages */
+static pj_status_t logging_on_tx_msg(pjsip_tx_data *tdata)
+{
+    
+    /* Important note:
+     *	tp_info field is only valid after outgoing messages has passed
+     *	transport layer. So don't try to access tp_info when the module
+     *	has lower priority than transport layer.
+     */
+
+    PJ_LOG(5,(THIS_FILE, "TX %d bytes %s to %s %s:%d:\n"
+			 "%.*s\n"
+			 "--end msg--",
+			 (tdata->buf.cur - tdata->buf.start),
+			 pjsip_tx_data_get_info(tdata),
+			 tdata->tp_info.transport->type_name,
+			 tdata->tp_info.dst_name,
+			 tdata->tp_info.dst_port,
+			 (int)(tdata->buf.cur - tdata->buf.start),
+			 tdata->buf.start));
+
+    /* Always return success, otherwise message will not get sent! */
+    return PJ_SUCCESS;
+}
+
+/* The module instance. */
+static pjsip_module mod_msg_logger = 
+{
+    NULL, NULL,				/* prev, next.		*/
+    { "mod-msg-logger", 14 },		/* Name.		*/
+    -1,					/* Id			*/
+    PJSIP_MOD_PRIORITY_TRANSPORT_LAYER-1,/* Priority	        */
+    NULL,				/* load()		*/
+    NULL,				/* start()		*/
+    NULL,				/* stop()		*/
+    NULL,				/* unload()		*/
+    &logging_on_rx_msg,			/* on_rx_request()	*/
+    &logging_on_rx_msg,			/* on_rx_response()	*/
+    &logging_on_tx_msg,			/* on_tx_request.	*/
+    &logging_on_tx_msg,			/* on_tx_response()	*/
+    NULL,				/* on_tsx_state()	*/
+
+};
+
+
+static pj_status_t init_stack(void)
+{
+    pj_status_t status;
+
+    /* Must init PJLIB first: */
+    status = pj_init();
+    PJ_ASSERT_RETURN(status == PJ_SUCCESS, status);
+
+
+    /* Then init PJLIB-UTIL: */
+    status = pjlib_util_init();
+    PJ_ASSERT_RETURN(status == PJ_SUCCESS, status);
+
+
+    /* Must create a pool factory before we can allocate any memory. */
+    pj_caching_pool_init(&global.cp, &pj_pool_factory_default_policy, 0);
+
+    /* Create the endpoint: */
+    status = pjsip_endpt_create(&global.cp.factory, NULL, &global.endpt);
+    PJ_ASSERT_RETURN(status == PJ_SUCCESS, status);
+
+    /* Init transaction layer for stateful proxy only */
+#if STATEFUL
+    status = pjsip_tsx_layer_init_module(global.endpt);
+    PJ_ASSERT_RETURN(status == PJ_SUCCESS, status);
+#endif
+
+    /* Create listening transport */
+    {
+	pj_sockaddr_in addr;
+
+	addr.sin_family = PJ_AF_INET;
+	addr.sin_addr.s_addr = 0;
+	addr.sin_port = pj_htons((pj_uint16_t)global.port);
+
+	status = pjsip_udp_transport_start( global.endpt, &addr, 
+					    NULL, 1, NULL);
+	if (status != PJ_SUCCESS)
+	    return status;
+    }
+
+    /* Create pool for the application */
+    global.pool = pj_pool_create(&global.cp.factory, "proxyapp", 
+				 4000, 4000, NULL);
+
+    /* Register the logger module */
+    pjsip_endpt_register_module(global.endpt, &mod_msg_logger);
+
+    return PJ_SUCCESS;
+}
+
+
+static pj_status_t init_proxy(void)
+{
+    pj_in_addr addr;
+    unsigned i;
+
+    /* List all names matching local endpoint.
+     * Note that PJLIB version 0.6 and newer has a function to
+     * enumerate local IP interface (pj_enum_ip_interface()), so
+     * by using it would be possible to list all IP interfaces in
+     * this host.
+     */
+
+    /* The first address is important since this would be the one
+     * to be added in Record-Route.
+     */
+    if (pj_gethostip(&addr) == PJ_SUCCESS) {
+	pj_strdup2(global.pool, &global.name[global.name_cnt].host,
+		   pj_inet_ntoa(addr));
+	global.name[global.name_cnt].port = global.port;
+	global.name_cnt++;
+    }
+
+    global.name[global.name_cnt].host = pj_str("127.0.0.1");
+    global.name[global.name_cnt].port = global.port;
+    global.name_cnt++;
+
+    global.name[global.name_cnt].host = *pj_gethostname();
+    global.name[global.name_cnt].port = global.port;
+    global.name_cnt++;
+
+    global.name[global.name_cnt].host = pj_str("localhost");
+    global.name[global.name_cnt].port = global.port;
+    global.name_cnt++;
+
+    PJ_LOG(3,(THIS_FILE, "Proxy started, listening on port %d", global.port));
+    PJ_LOG(3,(THIS_FILE, "Local host aliases:"));
+    for (i=0; i<global.name_cnt; ++i) {
+	PJ_LOG(3,(THIS_FILE, " %.*s:%d", 
+		  (int)global.name[i].host.slen,
+		  global.name[i].host.ptr,
+		  global.name[i].port));
+    }
+
+    if (global.record_route) {
+	PJ_LOG(3,(THIS_FILE, "Using Record-Route mode"));
+    }
+
+    return PJ_SUCCESS;
+}
+
+
+#if PJ_HAS_THREADS
+static int worker_thread(void *p)
+{
+    pj_time_val delay = {0, 10};
+
+    PJ_UNUSED_ARG(p);
+
+    while (!global.quit_flag) {
+	pjsip_endpt_handle_events(global.endpt, &delay);
+    }
+
+    return 0;
+}
+#endif
+
+
+/* Utility to determine if URI is local to this host. */
+static pj_bool_t is_uri_local(const pjsip_sip_uri *uri)
+{
+    unsigned i;
+    for (i=0; i<global.name_cnt; ++i) {
+	if ((uri->port == global.name[i].port ||
+	     (uri->port==0 && global.name[i].port==5060)) &&
+	    pj_stricmp(&uri->host, &global.name[i].host)==0)
+	{
+	    /* Match */
+	    return PJ_TRUE;
+	}
+    }
+
+    /* Doesn't match */
+    return PJ_FALSE;
+}
+
+
+/* Proxy utility to verify incoming requests.
+ * Return non-zero if verification failed.
+ */
+static pj_status_t proxy_verify_request(pjsip_rx_data *rdata)
+{
+    const pj_str_t STR_PROXY_REQUIRE = {"Proxy-Require", 13};
+
+    /* RFC 3261 Section 16.3 Request Validation */
+
+    /* Before an element can proxy a request, it MUST verify the message's
+     * validity.  A valid message must pass the following checks:
+     * 
+     * 1. Reasonable Syntax
+     * 2. URI scheme
+     * 3. Max-Forwards
+     * 4. (Optional) Loop Detection
+     * 5. Proxy-Require
+     * 6. Proxy-Authorization
+     */
+
+    /* 1. Reasonable Syntax.
+     * This would have been checked by transport layer.
+     */
+
+    /* 2. URI scheme.
+     * We only want to support "sip:" URI scheme for this simple proxy.
+     */
+    if (!PJSIP_URI_SCHEME_IS_SIP(rdata->msg_info.msg->line.req.uri)) {
+	pjsip_endpt_respond_stateless(global.endpt, rdata, 
+				      PJSIP_SC_UNSUPPORTED_URI_SCHEME, NULL,
+				      NULL, NULL);
+	return PJSIP_ERRNO_FROM_SIP_STATUS(PJSIP_SC_UNSUPPORTED_URI_SCHEME);
+    }
+
+    /* 3. Max-Forwards.
+     * Send error if Max-Forwards is 1 or lower.
+     */
+    if (rdata->msg_info.max_fwd && rdata->msg_info.max_fwd->ivalue <= 1) {
+	pjsip_endpt_respond_stateless(global.endpt, rdata, 
+				      PJSIP_SC_TOO_MANY_HOPS, NULL,
+				      NULL, NULL);
+	return PJSIP_ERRNO_FROM_SIP_STATUS(PJSIP_SC_TOO_MANY_HOPS);
+    }
+
+    /* 4. (Optional) Loop Detection.
+     * Nah, we don't do that with this simple proxy.
+     */
+
+    /* 5. Proxy-Require */
+    if (pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &STR_PROXY_REQUIRE, 
+				   NULL) != NULL) 
+    {
+	pjsip_endpt_respond_stateless(global.endpt, rdata, 
+				      PJSIP_SC_BAD_EXTENSION, NULL,
+				      NULL, NULL);
+	return PJSIP_ERRNO_FROM_SIP_STATUS(PJSIP_SC_BAD_EXTENSION);
+    }
+
+    /* 6. Proxy-Authorization.
+     * Nah, we don't require any authorization with this sample.
+     */
+
+    return PJ_SUCCESS;
+}
+
+
+/* Process route information in the reqeust */
+static pj_status_t proxy_process_routing(pjsip_tx_data *tdata)
+{
+    pjsip_sip_uri *target;
+    pjsip_route_hdr *hroute;
+
+    /* RFC 3261 Section 16.4 Route Information Preprocessing */
+
+    target = (pjsip_sip_uri*) tdata->msg->line.req.uri;
+
+    /* The proxy MUST inspect the Request-URI of the request.  If the
+     * Request-URI of the request contains a value this proxy previously
+     * placed into a Record-Route header field (see Section 16.6 item 4),
+     * the proxy MUST replace the Request-URI in the request with the last
+     * value from the Route header field, and remove that value from the
+     * Route header field.  The proxy MUST then proceed as if it received
+     * this modified request.
+     */
+    /* Nah, we don't want to support this */
+
+    /* If the Request-URI contains a maddr parameter, the proxy MUST check
+     * to see if its value is in the set of addresses or domains the proxy
+     * is configured to be responsible for.  If the Request-URI has a maddr
+     * parameter with a value the proxy is responsible for, and the request
+     * was received using the port and transport indicated (explicitly or by
+     * default) in the Request-URI, the proxy MUST strip the maddr and any
+     * non-default port or transport parameter and continue processing as if
+     * those values had not been present in the request.
+     */
+    if (target->maddr_param.slen != 0) {
+	pjsip_sip_uri maddr_uri;
+
+	maddr_uri.host = target->maddr_param;
+	maddr_uri.port = global.port;
+
+	if (is_uri_local(&maddr_uri)) {
+	    target->maddr_param.slen = 0;
+	    target->port = 0;
+	    target->transport_param.slen = 0;
+	}
+    }
+
+    /* If the first value in the Route header field indicates this proxy,
+     * the proxy MUST remove that value from the request.
+     */
+    hroute = (pjsip_route_hdr*) 
+	      pjsip_msg_find_hdr(tdata->msg, PJSIP_H_ROUTE, NULL);
+    if (hroute && is_uri_local((pjsip_sip_uri*)hroute->name_addr.uri)) {
+	pj_list_erase(hroute);
+    }
+
+    return PJ_SUCCESS;
+}
+
+
+/* Postprocess the request before forwarding it */
+static void proxy_postprocess(pjsip_tx_data *tdata)
+{
+    /* Optionally record-route */
+    if (global.record_route) {
+	char uribuf[128];
+	pj_str_t uri;
+	const pj_str_t H_RR = { "Record-Route", 12 };
+	pjsip_generic_string_hdr *rr;
+
+	pj_ansi_snprintf(uribuf, sizeof(uribuf), "<sip:%.*s:%d;lr>",
+			 (int)global.name[0].host.slen,
+			 global.name[0].host.ptr,
+			 global.name[0].port);
+	uri = pj_str(uribuf);
+	rr = pjsip_generic_string_hdr_create(tdata->pool,
+					     &H_RR, &uri);
+	pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr*)rr);
+    }
+}
+
+
+/* Calculate new target for the request */
+static pj_status_t proxy_calculate_target(pjsip_rx_data *rdata,
+					  pjsip_tx_data *tdata)
+{
+    pjsip_sip_uri *target;
+
+    /* RFC 3261 Section 16.5 Determining Request Targets */
+
+    target = (pjsip_sip_uri*) tdata->msg->line.req.uri;
+
+    /* If the Request-URI of the request contains an maddr parameter, the
+     * Request-URI MUST be placed into the target set as the only target
+     * URI, and the proxy MUST proceed to Section 16.6.
+     */
+    if (target->maddr_param.slen) {
+	proxy_postprocess(tdata);
+	return PJ_SUCCESS;
+    }
+
+
+    /* If the domain of the Request-URI indicates a domain this element is
+     * not responsible for, the Request-URI MUST be placed into the target
+     * set as the only target, and the element MUST proceed to the task of
+     * Request Forwarding (Section 16.6).
+     */
+    if (!is_uri_local(target)) {
+	proxy_postprocess(tdata);
+	return PJ_SUCCESS;
+    }
+
+    /* If the target set for the request has not been predetermined as
+     * described above, this implies that the element is responsible for the
+     * domain in the Request-URI, and the element MAY use whatever mechanism
+     * it desires to determine where to send the request. 
+     */
+
+    /* We're not interested to receive request destined to us, so
+     * respond with 404/Not Found (only if request is not ACK!).
+     */
+    if (rdata->msg_info.msg->line.req.method.id != PJSIP_ACK_METHOD) {
+	pjsip_endpt_respond_stateless(global.endpt, rdata,
+				      PJSIP_SC_NOT_FOUND, NULL,
+				      NULL, NULL);
+    }
+
+    /* Delete the request since we're not forwarding it */
+    pjsip_tx_data_dec_ref(tdata);
+
+    return PJSIP_ERRNO_FROM_SIP_STATUS(PJSIP_SC_NOT_FOUND);
+}
+
+
+/* Destroy stack */
+static void destroy_stack(void)
+{
+    pjsip_endpt_destroy(global.endpt);
+    pj_pool_release(global.pool);
+    pj_caching_pool_destroy(&global.cp);
+
+    pj_shutdown();
+}
+
diff --git a/pjsip-apps/src/samples/stateful_proxy.c b/pjsip-apps/src/samples/stateful_proxy.c
new file mode 100644
index 00000000..d83ec91c
--- /dev/null
+++ b/pjsip-apps/src/samples/stateful_proxy.c
@@ -0,0 +1,580 @@
+/* $Id$ */
+/* 
+ * Copyright (C) 2003-2007 Benny Prijono <benny@prijono.org>
+ *
+ * This program 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.
+ *
+ * This program 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 
+ */
+#define THIS_FILE   "stateful_proxy.c"
+
+/* Common proxy functions */
+#define STATEFUL    1
+#include "proxy.h"
+
+
+/*
+ * mod_stateful_proxy is the module to receive SIP request and
+ * response message that is outside any transaction context.
+ */
+static pj_bool_t proxy_on_rx_request(pjsip_rx_data *rdata );
+static pj_bool_t proxy_on_rx_response(pjsip_rx_data *rdata );
+
+static pjsip_module mod_stateful_proxy =
+{
+    NULL, NULL,				/* prev, next.		*/
+    { "mod-stateful-proxy", 18 },	/* Name.		*/
+    -1,					/* Id			*/
+    PJSIP_MOD_PRIORITY_UA_PROXY_LAYER,	/* Priority		*/
+    NULL,				/* load()		*/
+    NULL,				/* start()		*/
+    NULL,				/* stop()		*/
+    NULL,				/* unload()		*/
+    &proxy_on_rx_request,		/* on_rx_request()	*/
+    &proxy_on_rx_response,		/* on_rx_response()	*/
+    NULL,				/* on_tx_request.	*/
+    NULL,				/* on_tx_response()	*/
+    NULL,				/* on_tsx_state()	*/
+};
+
+
+/*
+ * mod_tu (tu=Transaction User) is the module to receive notification
+ * from transaction when the transaction state has changed.
+ */
+static void tu_on_tsx_state(pjsip_transaction *tsx, pjsip_event *event);
+
+static pjsip_module mod_tu =
+{
+    NULL, NULL,				/* prev, next.		*/
+    { "mod-transaction-user", 20 },	/* Name.		*/
+    -1,					/* Id			*/
+    PJSIP_MOD_PRIORITY_APPLICATION,	/* Priority		*/
+    NULL,				/* load()		*/
+    NULL,				/* start()		*/
+    NULL,				/* stop()		*/
+    NULL,				/* unload()		*/
+    NULL,				/* on_rx_request()	*/
+    NULL,				/* on_rx_response()	*/
+    NULL,				/* on_tx_request.	*/
+    NULL,				/* on_tx_response()	*/
+    &tu_on_tsx_state,			/* on_tsx_state()	*/
+};
+
+
+/* This is the data that is attached to the UAC transaction */
+struct uac_data
+{
+    pjsip_transaction	*uas_tsx;
+    pj_timer_entry	 timer;
+};
+
+
+/* This is the data that is attached to the UAS transaction */
+struct uas_data
+{
+    pjsip_transaction	*uac_tsx;
+};
+
+
+
+static pj_status_t init_stateful_proxy(void)
+{
+    pj_status_t status;
+
+    status = pjsip_endpt_register_module( global.endpt, &mod_stateful_proxy);
+    PJ_ASSERT_RETURN(status == PJ_SUCCESS, 1);
+
+    status = pjsip_endpt_register_module( global.endpt, &mod_tu);
+    PJ_ASSERT_RETURN(status == PJ_SUCCESS, 1);
+
+    return PJ_SUCCESS;
+}
+
+
+/* Callback to be called to handle new incoming requests. */
+static pj_bool_t proxy_on_rx_request( pjsip_rx_data *rdata )
+{
+    pjsip_transaction *uas_tsx, *uac_tsx;
+    struct uac_data *uac_data;
+    struct uas_data *uas_data;
+    pjsip_tx_data *tdata;
+    pj_status_t status;
+
+    if (rdata->msg_info.msg->line.req.method.id != PJSIP_CANCEL_METHOD) {
+
+	/* Verify incoming request */
+	status = proxy_verify_request(rdata);
+	if (status != PJ_SUCCESS) {
+	    app_perror("RX invalid request", status);
+	    return PJ_TRUE;
+	}
+
+	/*
+	 * Request looks sane, next clone the request to create transmit data.
+	 */
+	status = pjsip_endpt_create_request_fwd(global.endpt, rdata, NULL,
+						NULL, 0, &tdata);
+	if (status != PJ_SUCCESS) {
+	    pjsip_endpt_respond_stateless(global.endpt, rdata,
+					  PJSIP_SC_INTERNAL_SERVER_ERROR, 
+					  NULL, NULL, NULL);
+	    return PJ_TRUE;
+	}
+
+
+	/* Process routing */
+	status = proxy_process_routing(tdata);
+	if (status != PJ_SUCCESS) {
+	    app_perror("Error processing route", status);
+	    return PJ_TRUE;
+	}
+
+	/* Calculate target */
+	status = proxy_calculate_target(rdata, tdata);
+	if (status != PJ_SUCCESS) {
+	    app_perror("Error calculating target", status);
+	    return PJ_TRUE;
+	}
+
+	/* Everything is set to forward the request. */
+
+	/* If this is an ACK request, forward statelessly.
+	 * This happens if the proxy records route and this ACK
+	 * is sent for 2xx response. An ACK that is sent for non-2xx
+	 * final response will be absorbed by transaction layer, and
+	 * it will not be received by on_rx_request() callback.
+	 */
+	if (tdata->msg->line.req.method.id == PJSIP_ACK_METHOD) {
+	    status = pjsip_endpt_send_request_stateless(global.endpt, tdata, 
+							NULL, NULL);
+	    if (status != PJ_SUCCESS) {
+		app_perror("Error forwarding request", status);
+		return PJ_TRUE;
+	    }
+
+	    return PJ_TRUE;
+	}
+
+	/* Create UAC transaction for forwarding the request. 
+	 * Set our module as the transaction user to receive further
+	 * events from this transaction.
+	 */
+	status = pjsip_tsx_create_uac(&mod_tu, tdata, &uac_tsx);
+	if (status != PJ_SUCCESS) {
+	    pjsip_tx_data_dec_ref(tdata);
+	    pjsip_endpt_respond_stateless(global.endpt, rdata, 
+					  PJSIP_SC_INTERNAL_SERVER_ERROR, 
+					  NULL, NULL, NULL);
+	    return PJ_TRUE;
+	}
+
+	/* Create UAS transaction to handle incoming request */
+	status = pjsip_tsx_create_uas(&mod_tu, rdata, &uas_tsx);
+	if (status != PJ_SUCCESS) {
+	    pjsip_tx_data_dec_ref(tdata);
+	    pjsip_endpt_respond_stateless(global.endpt, rdata, 
+					  PJSIP_SC_INTERNAL_SERVER_ERROR, 
+					  NULL, NULL, NULL);
+	    pjsip_tsx_terminate(uac_tsx, PJSIP_SC_INTERNAL_SERVER_ERROR);
+	    return PJ_TRUE;
+	}
+
+	/* Feed the request to the UAS transaction to drive it's state 
+	 * out of NULL state. 
+	 */
+	pjsip_tsx_recv_msg(uas_tsx, rdata);
+
+	/* Attach a data to the UAC transaction, to be used to find the
+	 * UAS transaction when we receive response in the UAC side.
+	 */
+	uac_data = (struct uac_data*)
+		   pj_pool_alloc(uac_tsx->pool, sizeof(struct uac_data));
+	uac_data->uas_tsx = uas_tsx;
+	uac_tsx->mod_data[mod_tu.id] = (void*)uac_data;
+
+	/* Attach data to the UAS transaction, to find the UAC transaction
+	 * when cancelling INVITE request.
+	 */
+	uas_data = (struct uas_data*)
+		    pj_pool_alloc(uas_tsx->pool, sizeof(struct uas_data));
+	uas_data->uac_tsx = uac_tsx;
+	uas_tsx->mod_data[mod_tu.id] = (void*)uas_data;
+
+	/* Everything is setup, forward the request */
+	status = pjsip_tsx_send_msg(uac_tsx, tdata);
+	if (status != PJ_SUCCESS) {
+	    pjsip_tx_data *err_res;
+
+	    /* Fail to send request, for some reason */
+
+	    /* Destroy transmit data */
+	    pjsip_tx_data_dec_ref(tdata);
+
+	    /* I think UAC transaction should have been destroyed when
+	     * it fails to send request, so no need to destroy it.
+	    pjsip_tsx_terminate(uac_tsx, PJSIP_SC_INTERNAL_SERVER_ERROR);
+	     */
+
+	    /* Send 500/Internal Server Error to UAS transaction */
+	    pjsip_endpt_create_response(global.endpt, rdata,
+					500, NULL, &err_res);
+	    pjsip_tsx_send_msg(uas_tsx, err_res);
+
+	    return PJ_TRUE;
+	}
+
+	/* Send 100/Trying if this is an INVITE */
+	if (rdata->msg_info.msg->line.req.method.id == PJSIP_INVITE_METHOD) {
+	    pjsip_tx_data *res100;
+
+	    pjsip_endpt_create_response(global.endpt, rdata, 100, NULL, 
+					&res100);
+	    pjsip_tsx_send_msg(uas_tsx, res100);
+	}
+
+    } else {
+	/* This is CANCEL request */
+	pjsip_transaction *invite_uas;
+	struct uas_data *uas_data;
+	pj_str_t key;
+	
+	/* Find the UAS INVITE transaction */
+	pjsip_tsx_create_key(rdata->tp_info.pool, &key, PJSIP_UAS_ROLE,
+			     &pjsip_invite_method, rdata);
+	invite_uas = pjsip_tsx_layer_find_tsx(&key, PJ_TRUE);
+	if (!invite_uas) {
+	    /* Invite transaction not found, respond CANCEL with 481 */
+	    pjsip_endpt_respond_stateless(global.endpt, rdata, 481, NULL,
+					  NULL, NULL);
+	    return PJ_TRUE;
+	}
+
+	/* Respond 200 OK to CANCEL */
+	pjsip_endpt_respond(global.endpt, NULL, rdata, 200, NULL, NULL,
+			    NULL, NULL);
+
+	/* Send CANCEL to cancel the UAC transaction.
+	 * The UAS INVITE transaction will get final response when
+	 * we receive final response from the UAC INVITE transaction.
+	 */
+	uas_data = (struct uas_data*) invite_uas->mod_data[mod_tu.id];
+	if (uas_data->uac_tsx) {
+	    pjsip_tx_data *cancel;
+
+	    pj_mutex_lock(uas_data->uac_tsx->mutex);
+
+	    pjsip_endpt_create_cancel(global.endpt, uas_data->uac_tsx->last_tx,
+				      &cancel);
+	    pjsip_endpt_send_request(global.endpt, cancel, -1, NULL, NULL);
+
+	    pj_mutex_unlock(uas_data->uac_tsx->mutex);
+	}
+
+	/* Unlock UAS tsx because it is locked in find_tsx() */
+	pj_mutex_unlock(invite_uas->mutex);
+    }
+
+    return PJ_TRUE;
+}
+
+
+/* Callback to be called to handle incoming response outside
+ * any transactions. This happens for example when 2xx/OK
+ * for INVITE is received and transaction will be destroyed
+ * immediately, so we need to forward the subsequent 2xx/OK
+ * retransmission statelessly.
+ */
+static pj_bool_t proxy_on_rx_response( pjsip_rx_data *rdata )
+{
+    pjsip_tx_data *tdata;
+    pjsip_response_addr res_addr;
+    pjsip_via_hdr *hvia;
+    pj_status_t status;
+
+    /* Create response to be forwarded upstream (Via will be stripped here) */
+    status = pjsip_endpt_create_response_fwd(global.endpt, rdata, 0, &tdata);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error creating response", status);
+	return PJ_TRUE;
+    }
+
+    /* Get topmost Via header */
+    hvia = (pjsip_via_hdr*) pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, NULL);
+    if (hvia == NULL) {
+	/* Invalid response! Just drop it */
+	pjsip_tx_data_dec_ref(tdata);
+	return PJ_TRUE;
+    }
+
+    /* Calculate the address to forward the response */
+    pj_bzero(&res_addr, sizeof(res_addr));
+    res_addr.dst_host.type = PJSIP_TRANSPORT_UDP;
+    res_addr.dst_host.flag = 
+	pjsip_transport_get_flag_from_type(PJSIP_TRANSPORT_UDP);
+
+    /* Destination address is Via's received param */
+    res_addr.dst_host.addr.host = hvia->recvd_param;
+    if (res_addr.dst_host.addr.host.slen == 0) {
+	/* Someone has messed up our Via header! */
+	res_addr.dst_host.addr.host = hvia->sent_by.host;
+    }
+
+    /* Destination port is the rport */
+    if (hvia->rport_param != 0 && hvia->rport_param != -1)
+	res_addr.dst_host.addr.port = hvia->rport_param;
+
+    if (res_addr.dst_host.addr.port == 0) {
+	/* Ugh, original sender didn't put rport!
+	 * At best, can only send the response to the port in Via.
+	 */
+	res_addr.dst_host.addr.port = hvia->sent_by.port;
+    }
+
+    /* Forward response */
+    status = pjsip_endpt_send_response(global.endpt, &res_addr, tdata,
+				       NULL, NULL);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error forwarding response", status);
+	return PJ_TRUE;
+    }
+
+    return PJ_TRUE;
+}
+
+
+/* Callback to be called to handle transaction state changed. */
+static void tu_on_tsx_state(pjsip_transaction *tsx, pjsip_event *event)
+{
+    struct uac_data *uac_data;
+    pj_status_t status;
+
+    if (tsx->role == PJSIP_ROLE_UAS) {
+	if (tsx->state == PJSIP_TSX_STATE_TERMINATED) {
+	    struct uas_data *uas_data;
+
+	    uas_data = (struct uas_data*) tsx->mod_data[mod_tu.id];
+	    if (uas_data->uac_tsx) {
+		uac_data = (struct uac_data*)
+			   uas_data->uac_tsx->mod_data[mod_tu.id];
+		uac_data->uas_tsx = NULL;
+	    }
+		       
+	}
+	return;
+    }
+
+    /* Get the data that we attached to the UAC transaction previously */
+    uac_data = (struct uac_data*) tsx->mod_data[mod_tu.id];
+
+
+    /* Handle incoming response */
+    if (event->body.tsx_state.type == PJSIP_EVENT_RX_MSG) {
+
+	pjsip_rx_data *rdata;
+	pjsip_response_addr res_addr;
+        pjsip_via_hdr *hvia;
+	pjsip_tx_data *tdata;
+
+	rdata = event->body.tsx_state.src.rdata;
+
+	/* Do not forward 100 response for INVITE (we already responded
+	 * INVITE with 100)
+	 */
+	if (tsx->method.id == PJSIP_INVITE_METHOD && 
+	    rdata->msg_info.msg->line.status.code == 100)
+	{
+	    return;
+	}
+
+	/* Create response to be forwarded upstream 
+	 * (Via will be stripped here) 
+	 */
+	status = pjsip_endpt_create_response_fwd(global.endpt, rdata, 0, 
+						 &tdata);
+	if (status != PJ_SUCCESS) {
+	    app_perror("Error creating response", status);
+	    return;
+	}
+
+	/* Get topmost Via header of the new response */
+	hvia = (pjsip_via_hdr*) pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, 
+						   NULL);
+	if (hvia == NULL) {
+	    /* Invalid response! Just drop it */
+	    pjsip_tx_data_dec_ref(tdata);
+	    return;
+	}
+
+	/* Calculate the address to forward the response */
+	pj_bzero(&res_addr, sizeof(res_addr));
+	res_addr.dst_host.type = PJSIP_TRANSPORT_UDP;
+	res_addr.dst_host.flag = 
+	    pjsip_transport_get_flag_from_type(PJSIP_TRANSPORT_UDP);
+
+	/* Destination address is Via's received param */
+	res_addr.dst_host.addr.host = hvia->recvd_param;
+	if (res_addr.dst_host.addr.host.slen == 0) {
+	    /* Someone has messed up our Via header! */
+	    res_addr.dst_host.addr.host = hvia->sent_by.host;
+	}
+
+	/* Destination port is the rport */
+	if (hvia->rport_param != 0 && hvia->rport_param != -1)
+	    res_addr.dst_host.addr.port = hvia->rport_param;
+
+	if (res_addr.dst_host.addr.port == 0) {
+	    /* Ugh, original sender didn't put rport!
+	     * At best, can only send the response to the port in Via.
+	     */
+	    res_addr.dst_host.addr.port = hvia->sent_by.port;
+	}
+
+	/* Forward response with the UAS transaction */
+	pjsip_tsx_send_msg(uac_data->uas_tsx, tdata);
+
+    }
+
+    /* If UAC transaction is terminated, terminate the UAS as well.
+     * This could happen because of:
+     *	- timeout on the UAC side
+     *  - receipt of 2xx response to INVITE
+     */
+    if (tsx->state == PJSIP_TSX_STATE_TERMINATED && uac_data->uas_tsx) {
+
+	pjsip_transaction *uas_tsx;
+	struct uas_data *uas_data;
+
+	uas_tsx = uac_data->uas_tsx;
+	uas_data = (struct uas_data*) uas_tsx->mod_data[mod_tu.id];
+	uas_data->uac_tsx = NULL;
+
+	if (event->body.tsx_state.type == PJSIP_EVENT_TIMER) {
+
+	    /* Send 408/Timeout if this is an INVITE transaction, since
+	     * we must have sent provisional response before. For non
+	     * INVITE transaction, just destroy it.
+	     */
+	    if (tsx->method.id == PJSIP_INVITE_METHOD) {
+
+		pjsip_tx_data *tdata = uas_tsx->last_tx;
+
+		tdata->msg->line.status.code = PJSIP_SC_REQUEST_TIMEOUT;
+		tdata->msg->line.status.reason = pj_str("Request timed out");
+		tdata->msg->body = NULL;
+
+		pjsip_tx_data_add_ref(tdata);
+		pjsip_tx_data_invalidate_msg(tdata);
+
+		pjsip_tsx_send_msg(uas_tsx, tdata);
+
+	    } else {
+		/* For non-INVITE, just destroy the UAS transaction */
+		pjsip_tsx_terminate(uas_tsx, PJSIP_SC_REQUEST_TIMEOUT);
+	    }
+
+	} else if (event->body.tsx_state.type == PJSIP_EVENT_RX_MSG) {
+
+	    if (uas_tsx->state < PJSIP_TSX_STATE_TERMINATED) {
+		pjsip_msg *msg;
+		int code;
+
+		msg = event->body.tsx_state.src.rdata->msg_info.msg;
+		code = msg->line.status.code;
+
+		uac_data->uas_tsx = NULL;
+		pjsip_tsx_terminate(uas_tsx, code);
+	    }
+	}
+    }
+}
+
+
+/*
+ * main()
+ */
+int main(int argc, char *argv[])
+{
+    pj_status_t status;
+
+    global.port = 5060;
+    global.record_route = 0;
+
+    pj_log_set_level(4);
+
+    status = init_options(argc, argv);
+    if (status != PJ_SUCCESS)
+	return 1;
+
+    status = init_stack();
+    if (status != PJ_SUCCESS) {
+	app_perror("Error initializing stack", status);
+	return 1;
+    }
+
+    status = init_proxy();
+    if (status != PJ_SUCCESS) {
+	app_perror("Error initializing proxy", status);
+	return 1;
+    }
+
+    status = init_stateful_proxy();
+    if (status != PJ_SUCCESS) {
+	app_perror("Error initializing stateful proxy", status);
+	return 1;
+    }
+
+#if PJ_HAS_THREADS
+    status = pj_thread_create(global.pool, "sproxy", &worker_thread, 
+			      NULL, 0, 0, &global.thread);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error creating thread", status);
+	return 1;
+    }
+
+    while (!global.quit_flag) {
+	char line[10];
+
+	puts("\n"
+	     "Menu:\n"
+	     "  q    quit\n"
+	     "  d    dump status\n"
+	     "  dd   dump detailed status\n"
+	     "");
+
+	fgets(line, sizeof(line), stdin);
+
+	if (line[0] == 'q') {
+	    global.quit_flag = PJ_TRUE;
+	} else if (line[0] == 'd') {
+	    pj_bool_t detail = (line[1] == 'd');
+	    pjsip_endpt_dump(global.endpt, detail);
+	    pjsip_tsx_layer_dump(detail);
+	}
+    }
+
+    pj_thread_join(global.thread);
+
+#else
+    puts("\nPress Ctrl-C to quit\n");
+    for (;;) {
+	pj_time_val delay = {0, 0};
+	pjsip_endpt_handle_events(global.endpt, &delay);
+    }
+#endif
+
+    destroy_stack();
+
+    return 0;
+}
+
diff --git a/pjsip-apps/src/samples/stateless_proxy.c b/pjsip-apps/src/samples/stateless_proxy.c
new file mode 100644
index 00000000..f40b263c
--- /dev/null
+++ b/pjsip-apps/src/samples/stateless_proxy.c
@@ -0,0 +1,250 @@
+/* $Id$ */
+/* 
+ * Copyright (C) 2003-2007 Benny Prijono <benny@prijono.org>
+ *
+ * This program 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.
+ *
+ * This program 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 
+ */
+#define THIS_FILE   "stateless_proxy.c"
+
+/* Common proxy functions */
+#define STATEFUL    0
+#include "proxy.h"
+
+
+/* Callback to be called to handle incoming requests. */
+static pj_bool_t on_rx_request( pjsip_rx_data *rdata );
+
+/* Callback to be called to handle incoming response. */
+static pj_bool_t on_rx_response( pjsip_rx_data *rdata );
+
+
+static pj_status_t init_stateless_proxy(void)
+{
+    static pjsip_module mod_stateless_proxy =
+    {
+	NULL, NULL,			    /* prev, next.	*/
+	{ "mod-stateless-proxy", 19 },	    /* Name.		*/
+	-1,				    /* Id		*/
+	PJSIP_MOD_PRIORITY_UA_PROXY_LAYER,  /* Priority		*/
+	NULL,				    /* load()		*/
+	NULL,				    /* start()		*/
+	NULL,				    /* stop()		*/
+	NULL,				    /* unload()		*/
+	&on_rx_request,			    /* on_rx_request()	*/
+	&on_rx_response,		    /* on_rx_response()	*/
+	NULL,				    /* on_tx_request.	*/
+	NULL,				    /* on_tx_response()	*/
+	NULL,				    /* on_tsx_state()	*/
+    };
+
+    pj_status_t status;
+
+    /* Register our module to receive incoming requests. */
+    status = pjsip_endpt_register_module( global.endpt, &mod_stateless_proxy);
+    PJ_ASSERT_RETURN(status == PJ_SUCCESS, 1);
+
+    return PJ_SUCCESS;
+}
+
+
+/* Callback to be called to handle incoming requests. */
+static pj_bool_t on_rx_request( pjsip_rx_data *rdata )
+{
+    pjsip_tx_data *tdata;
+    pj_status_t status;
+
+
+    /* Verify incoming request */
+    status = proxy_verify_request(rdata);
+    if (status != PJ_SUCCESS) {
+	app_perror("RX invalid request", status);
+	return PJ_TRUE;
+    }
+
+    /*
+     * Request looks sane, next clone the request to create transmit data.
+     */
+    status = pjsip_endpt_create_request_fwd(global.endpt, rdata, NULL,
+					    NULL, 0, &tdata);
+    if (status != PJ_SUCCESS) {
+	pjsip_endpt_respond_stateless(global.endpt, rdata,
+				      PJSIP_SC_INTERNAL_SERVER_ERROR, NULL, 
+				      NULL, NULL);
+	return PJ_TRUE;
+    }
+
+
+    /* Process routing */
+    status = proxy_process_routing(tdata);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error processing route", status);
+	return PJ_TRUE;
+    }
+
+    /* Calculate target */
+    status = proxy_calculate_target(rdata, tdata);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error calculating target", status);
+	return PJ_TRUE;
+    }
+
+    /* Target is set, forward the request */
+    status = pjsip_endpt_send_request_stateless(global.endpt, tdata, 
+						NULL, NULL);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error forwarding request", status);
+	return PJ_TRUE;
+    }
+
+    return PJ_TRUE;
+}
+
+
+/* Callback to be called to handle incoming response. */
+static pj_bool_t on_rx_response( pjsip_rx_data *rdata )
+{
+    pjsip_tx_data *tdata;
+    pjsip_response_addr res_addr;
+    pjsip_via_hdr *hvia;
+    pj_status_t status;
+
+    /* Create response to be forwarded upstream (Via will be stripped here) */
+    status = pjsip_endpt_create_response_fwd(global.endpt, rdata, 0, &tdata);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error creating response", status);
+	return PJ_TRUE;
+    }
+
+    /* Get topmost Via header */
+    hvia = (pjsip_via_hdr*) pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, NULL);
+    if (hvia == NULL) {
+	/* Invalid response! Just drop it */
+	pjsip_tx_data_dec_ref(tdata);
+	return PJ_TRUE;
+    }
+
+    /* Calculate the address to forward the response */
+    pj_bzero(&res_addr, sizeof(res_addr));
+    res_addr.dst_host.type = PJSIP_TRANSPORT_UDP;
+    res_addr.dst_host.flag = pjsip_transport_get_flag_from_type(PJSIP_TRANSPORT_UDP);
+
+    /* Destination address is Via's received param */
+    res_addr.dst_host.addr.host = hvia->recvd_param;
+    if (res_addr.dst_host.addr.host.slen == 0) {
+	/* Someone has messed up our Via header! */
+	res_addr.dst_host.addr.host = hvia->sent_by.host;
+    }
+
+    /* Destination port is the rpot */
+    if (hvia->rport_param != 0 && hvia->rport_param != -1)
+	res_addr.dst_host.addr.port = hvia->rport_param;
+
+    if (res_addr.dst_host.addr.port == 0) {
+	/* Ugh, original sender didn't put rport!
+	 * At best, can only send the response to the port in Via.
+	 */
+	res_addr.dst_host.addr.port = hvia->sent_by.port;
+    }
+
+    /* Forward response */
+    status = pjsip_endpt_send_response(global.endpt, &res_addr, tdata, 
+				       NULL, NULL);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error forwarding response", status);
+	return PJ_TRUE;
+    }
+
+    return PJ_TRUE;
+}
+
+
+/*
+ * main()
+ */
+int main(int argc, char *argv[])
+{
+    pj_status_t status;
+
+    global.port = 5060;
+    pj_log_set_level(4);
+
+    status = init_options(argc, argv);
+    if (status != PJ_SUCCESS)
+	return 1;
+
+    status = init_stack();
+    if (status != PJ_SUCCESS) {
+	app_perror("Error initializing stack", status);
+	return 1;
+    }
+
+    status = init_proxy();
+    if (status != PJ_SUCCESS) {
+	app_perror("Error initializing proxy", status);
+	return 1;
+    }
+
+    status = init_stateless_proxy();
+    if (status != PJ_SUCCESS) {
+	app_perror("Error initializing stateless proxy", status);
+	return 1;
+    }
+
+#if PJ_HAS_THREADS
+    status = pj_thread_create(global.pool, "sproxy", &worker_thread, 
+			      NULL, 0, 0, &global.thread);
+    if (status != PJ_SUCCESS) {
+	app_perror("Error creating thread", status);
+	return 1;
+    }
+
+    while (!global.quit_flag) {
+	char line[10];
+
+	puts("\n"
+	     "Menu:\n"
+	     "  q    quit\n"
+	     "  d    dump status\n"
+	     "  dd   dump detailed status\n"
+	     "");
+
+	fgets(line, sizeof(line), stdin);
+
+	if (line[0] == 'q') {
+	    global.quit_flag = PJ_TRUE;
+	} else if (line[0] == 'd') {
+	    pj_bool_t detail = (line[1] == 'd');
+	    pjsip_endpt_dump(global.endpt, detail);
+#if STATEFUL
+	    pjsip_tsx_layer_dump(detail);
+#endif
+	}
+    }
+
+    pj_thread_join(global.thread);
+
+#else
+    puts("\nPress Ctrl-C to quit\n");
+    for (;;) {
+	pj_time_val delay = {0, 0};
+	pjsip_endpt_handle_events(global.endpt, &delay);
+    }
+#endif
+
+    destroy_stack();
+
+    return 0;
+}
+