Import pjproject-2.0.1

1 files changed, 1377 insertions, 0 deletions

diff --git a/pjnath/src/pjturn-srv/allocation.c b/pjnath/src/pjturn-srv/allocation.c
new file mode 100644
index 0000000..9371635
--- /dev/null
+++ b/pjnath/src/pjturn-srv/allocation.c
@@ -0,0 +1,1377 @@
+/* $Id: allocation.c 3553 2011-05-05 06:14:19Z nanang $ */
+/* 
+ * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
+ * Copyright (C) 2003-2008 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 "turn.h"
+#include "auth.h"
+
+
+#define THIS_FILE   "allocation.c"
+
+
+enum {
+    TIMER_ID_NONE,
+    TIMER_ID_TIMEOUT,
+    TIMER_ID_DESTROY
+};
+
+#define DESTROY_DELAY	    {0, 500}
+#define PEER_TABLE_SIZE	    32
+
+#define MAX_CLIENT_BANDWIDTH	128  /* In Kbps */
+#define DEFA_CLIENT_BANDWIDTH	64
+
+#define MIN_LIFETIME		30
+#define MAX_LIFETIME		600
+#define DEF_LIFETIME		300
+
+
+/* Parsed Allocation request. */
+typedef struct alloc_request
+{
+    unsigned		tp_type;		    /* Requested transport  */
+    char		addr[PJ_INET6_ADDRSTRLEN];  /* Requested IP	    */
+    unsigned		bandwidth;		    /* Requested bandwidth  */
+    unsigned		lifetime;		    /* Lifetime.	    */
+    unsigned		rpp_bits;		    /* A bits		    */
+    unsigned		rpp_port;		    /* Requested port	    */
+} alloc_request;
+
+
+
+/* Prototypes */
+static void destroy_allocation(pj_turn_allocation *alloc);
+static pj_status_t create_relay(pj_turn_srv *srv,
+				pj_turn_allocation *alloc,
+				const pj_stun_msg *msg,
+				const alloc_request *req,
+				pj_turn_relay_res *relay);
+static void destroy_relay(pj_turn_relay_res *relay);
+static void on_rx_from_peer(pj_ioqueue_key_t *key, 
+                            pj_ioqueue_op_key_t *op_key, 
+                            pj_ssize_t bytes_read);
+static pj_status_t stun_on_send_msg(pj_stun_session *sess,
+				    void *token,
+				    const void *pkt,
+				    pj_size_t pkt_size,
+				    const pj_sockaddr_t *dst_addr,
+				    unsigned addr_len);
+static pj_status_t stun_on_rx_request(pj_stun_session *sess,
+				      const pj_uint8_t *pkt,
+				      unsigned pkt_len,
+				      const pj_stun_rx_data *rdata,
+				      void *token,
+				      const pj_sockaddr_t *src_addr,
+				      unsigned src_addr_len);
+static pj_status_t stun_on_rx_indication(pj_stun_session *sess,
+					 const pj_uint8_t *pkt,
+					 unsigned pkt_len,
+					 const pj_stun_msg *msg,
+					 void *token,
+					 const pj_sockaddr_t *src_addr,
+					 unsigned src_addr_len);
+
+/* Log allocation error */
+static void alloc_err(pj_turn_allocation *alloc, const char *title,
+		      pj_status_t status)
+{
+    char errmsg[PJ_ERR_MSG_SIZE];
+
+    pj_strerror(status, errmsg, sizeof(errmsg));
+    PJ_LOG(4,(alloc->obj_name, "%s for client %s: %s",
+	      title, alloc->info, errmsg));
+}
+
+
+/* Parse ALLOCATE request */
+static pj_status_t parse_allocate_req(alloc_request *cfg,
+				      pj_stun_session *sess,
+				      const pj_stun_rx_data *rdata,
+				      const pj_sockaddr_t *src_addr,
+				      unsigned src_addr_len)
+{
+    const pj_stun_msg *req = rdata->msg;
+    pj_stun_bandwidth_attr *attr_bw;
+    pj_stun_req_transport_attr *attr_req_tp;
+    pj_stun_res_token_attr *attr_res_token;
+    pj_stun_lifetime_attr *attr_lifetime;
+
+    pj_bzero(cfg, sizeof(*cfg));
+
+    /* Get BANDWIDTH attribute, if any. */
+    attr_bw = (pj_stun_uint_attr*)
+	      pj_stun_msg_find_attr(req, PJ_STUN_ATTR_BANDWIDTH, 0);
+    if (attr_bw) {
+	cfg->bandwidth = attr_bw->value;
+    } else {
+	cfg->bandwidth = DEFA_CLIENT_BANDWIDTH;
+    }
+
+    /* Check if we can satisfy the bandwidth */
+    if (cfg->bandwidth > MAX_CLIENT_BANDWIDTH) {
+	pj_stun_session_respond(sess, rdata, 
+				PJ_STUN_SC_ALLOCATION_QUOTA_REACHED,
+			        "Invalid bandwidth", NULL, PJ_TRUE,
+				src_addr, src_addr_len);
+	return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_ALLOCATION_QUOTA_REACHED);
+    }
+
+    /* MUST have REQUESTED-TRANSPORT attribute */
+    attr_req_tp = (pj_stun_uint_attr*)
+	          pj_stun_msg_find_attr(req, PJ_STUN_ATTR_REQ_TRANSPORT, 0);
+    if (attr_req_tp == NULL) {
+	pj_stun_session_respond(sess, rdata, PJ_STUN_SC_BAD_REQUEST,
+			        "Missing REQUESTED-TRANSPORT attribute", 
+				NULL, PJ_TRUE, src_addr, src_addr_len);
+	return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_BAD_REQUEST);
+    }
+
+    cfg->tp_type = PJ_STUN_GET_RT_PROTO(attr_req_tp->value);
+
+    /* Can only support UDP for now */
+    if (cfg->tp_type != PJ_TURN_TP_UDP) {
+	pj_stun_session_respond(sess, rdata, PJ_STUN_SC_UNSUPP_TRANSPORT_PROTO,
+				NULL, NULL, PJ_TRUE, src_addr, src_addr_len);
+	return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_UNSUPP_TRANSPORT_PROTO);
+    }
+
+    /* Get RESERVATION-TOKEN attribute, if any */
+    attr_res_token = (pj_stun_res_token_attr*)
+	             pj_stun_msg_find_attr(req, PJ_STUN_ATTR_RESERVATION_TOKEN,
+					   0);
+    if (attr_res_token) {
+	/* We don't support RESERVATION-TOKEN for now */
+	pj_stun_session_respond(sess, rdata, 
+				PJ_STUN_SC_BAD_REQUEST,
+				"RESERVATION-TOKEN is not supported", NULL, 
+				PJ_TRUE, src_addr, src_addr_len);
+	return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_BAD_REQUEST);
+    }
+
+    /* Get LIFETIME attribute */
+    attr_lifetime = (pj_stun_uint_attr*)
+	            pj_stun_msg_find_attr(req, PJ_STUN_ATTR_LIFETIME, 0);
+    if (attr_lifetime) {
+	cfg->lifetime = attr_lifetime->value;
+	if (cfg->lifetime < MIN_LIFETIME) {
+	    pj_stun_session_respond(sess, rdata, PJ_STUN_SC_BAD_REQUEST,
+				    "LIFETIME too short", NULL, 
+				    PJ_TRUE, src_addr, src_addr_len);
+	    return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_BAD_REQUEST);
+	}
+	if (cfg->lifetime > MAX_LIFETIME)
+	    cfg->lifetime = MAX_LIFETIME;
+    } else {
+	cfg->lifetime = DEF_LIFETIME;
+    }
+
+    return PJ_SUCCESS;
+}
+
+
+/* Respond to ALLOCATE request */
+static pj_status_t send_allocate_response(pj_turn_allocation *alloc,
+					  pj_stun_session *srv_sess,
+					  pj_turn_transport *transport,
+					  const pj_stun_rx_data *rdata)
+{
+    pj_stun_tx_data *tdata;
+    pj_status_t status;
+
+    /* Respond the original ALLOCATE request */
+    status = pj_stun_session_create_res(srv_sess, rdata, 0, NULL, &tdata);
+    if (status != PJ_SUCCESS)
+	return status;
+
+    /* Add XOR-RELAYED-ADDRESS attribute */
+    pj_stun_msg_add_sockaddr_attr(tdata->pool, tdata->msg,
+				  PJ_STUN_ATTR_XOR_RELAYED_ADDR, PJ_TRUE,
+				  &alloc->relay.hkey.addr,
+				  pj_sockaddr_get_len(&alloc->relay.hkey.addr));
+
+    /* Add LIFETIME. */
+    pj_stun_msg_add_uint_attr(tdata->pool, tdata->msg,
+			      PJ_STUN_ATTR_LIFETIME, 
+			      (unsigned)alloc->relay.lifetime);
+
+    /* Add BANDWIDTH */
+    pj_stun_msg_add_uint_attr(tdata->pool, tdata->msg,
+			      PJ_STUN_ATTR_BANDWIDTH,
+			      alloc->bandwidth);
+
+    /* Add RESERVATION-TOKEN */
+    PJ_TODO(ADD_RESERVATION_TOKEN);
+
+    /* Add XOR-MAPPED-ADDRESS */
+    pj_stun_msg_add_sockaddr_attr(tdata->pool, tdata->msg,
+				  PJ_STUN_ATTR_XOR_MAPPED_ADDR, PJ_TRUE,
+				  &alloc->hkey.clt_addr,
+				  pj_sockaddr_get_len(&alloc->hkey.clt_addr));
+    
+    /* Send the response */
+    return pj_stun_session_send_msg(srv_sess, transport, PJ_TRUE,
+				    PJ_FALSE, &alloc->hkey.clt_addr, 
+				    pj_sockaddr_get_len(&alloc->hkey.clt_addr),
+				    tdata);
+}
+
+
+/*
+ * Init credential for the allocation. We use static credential, meaning that
+ * the user's password must not change during allocation.
+ */
+static pj_status_t init_cred(pj_turn_allocation *alloc, const pj_stun_msg *req)
+{
+    const pj_stun_username_attr *user;
+    const pj_stun_realm_attr *realm;
+    const pj_stun_nonce_attr *nonce;
+    pj_status_t status;
+
+    realm = (const pj_stun_realm_attr*)
+	    pj_stun_msg_find_attr(req, PJ_STUN_ATTR_REALM, 0);
+    PJ_ASSERT_RETURN(realm != NULL, PJ_EBUG);
+
+    user = (const pj_stun_username_attr*)
+	   pj_stun_msg_find_attr(req, PJ_STUN_ATTR_USERNAME, 0);
+    PJ_ASSERT_RETURN(user != NULL, PJ_EBUG);
+
+    nonce = (const pj_stun_nonce_attr*)
+	    pj_stun_msg_find_attr(req, PJ_STUN_ATTR_NONCE, 0);
+    PJ_ASSERT_RETURN(nonce != NULL, PJ_EBUG);
+
+    /* Lookup the password */
+    status = pj_turn_get_password(NULL, NULL, &realm->value, 
+				  &user->value, alloc->pool, 
+				  &alloc->cred.data.static_cred.data_type, 
+				  &alloc->cred.data.static_cred.data);
+    if (status != PJ_SUCCESS)
+	return status;
+
+    /* Save credential */
+    alloc->cred.type = PJ_STUN_AUTH_CRED_STATIC;
+    pj_strdup(alloc->pool, &alloc->cred.data.static_cred.realm, &realm->value);
+    pj_strdup(alloc->pool, &alloc->cred.data.static_cred.username, &user->value);
+    pj_strdup(alloc->pool, &alloc->cred.data.static_cred.nonce, &nonce->value);
+
+    return PJ_SUCCESS;
+}
+
+
+/*
+ * Create new allocation.
+ */
+PJ_DEF(pj_status_t) pj_turn_allocation_create(pj_turn_transport *transport,
+					      const pj_sockaddr_t *src_addr,
+					      unsigned src_addr_len,
+					      const pj_stun_rx_data *rdata,
+					      pj_stun_session *srv_sess,
+					      pj_turn_allocation **p_alloc)
+{
+    pj_turn_srv *srv = transport->listener->server;
+    const pj_stun_msg *msg = rdata->msg;
+    pj_pool_t *pool;
+    alloc_request req;
+    pj_turn_allocation *alloc;
+    pj_stun_session_cb sess_cb;
+    char str_tmp[80];
+    pj_status_t status;
+
+    /* Parse ALLOCATE request */
+    status = parse_allocate_req(&req, srv_sess, rdata, src_addr, src_addr_len);
+    if (status != PJ_SUCCESS)
+	return status;
+
+    pool = pj_pool_create(srv->core.pf, "alloc%p", 1000, 1000, NULL);
+
+    /* Init allocation structure */
+    alloc = PJ_POOL_ZALLOC_T(pool, pj_turn_allocation);
+    alloc->pool = pool;
+    alloc->obj_name = pool->obj_name;
+    alloc->relay.tp.sock = PJ_INVALID_SOCKET;
+    alloc->server = transport->listener->server;
+
+    alloc->bandwidth = req.bandwidth;
+
+    /* Set transport */
+    alloc->transport = transport;
+    pj_turn_transport_add_ref(transport, alloc);
+
+    alloc->hkey.tp_type = transport->listener->tp_type;
+    pj_memcpy(&alloc->hkey.clt_addr, src_addr, src_addr_len);
+
+    status = pj_lock_create_recursive_mutex(pool, alloc->obj_name, 
+					    &alloc->lock);
+    if (status != PJ_SUCCESS) {
+	goto on_error;
+    }
+
+    /* Create peer hash table */
+    alloc->peer_table = pj_hash_create(pool, PEER_TABLE_SIZE);
+
+    /* Create channel hash table */
+    alloc->ch_table = pj_hash_create(pool, PEER_TABLE_SIZE);
+
+    /* Print info */
+    pj_ansi_strcpy(alloc->info, 
+		   pj_turn_tp_type_name(transport->listener->tp_type));
+    alloc->info[3] = ':';
+    pj_sockaddr_print(src_addr, alloc->info+4, sizeof(alloc->info)-4, 3);
+
+    /* Create STUN session to handle STUN communication with client */
+    pj_bzero(&sess_cb, sizeof(sess_cb));
+    sess_cb.on_send_msg = &stun_on_send_msg;
+    sess_cb.on_rx_request = &stun_on_rx_request;
+    sess_cb.on_rx_indication = &stun_on_rx_indication;
+    status = pj_stun_session_create(&srv->core.stun_cfg, alloc->obj_name,
+				    &sess_cb, PJ_FALSE, &alloc->sess);
+    if (status != PJ_SUCCESS) {
+	goto on_error;
+    }
+
+    /* Attach to STUN session */
+    pj_stun_session_set_user_data(alloc->sess, alloc);
+
+    /* Init authentication credential */
+    status = init_cred(alloc, msg);
+    if (status != PJ_SUCCESS) {
+	goto on_error;
+    }
+
+    /* Attach authentication credential to STUN session */
+    pj_stun_session_set_credential(alloc->sess, PJ_STUN_AUTH_LONG_TERM,
+				   &alloc->cred);
+
+    /* Create the relay resource */
+    status = create_relay(srv, alloc, msg, &req, &alloc->relay);
+    if (status != PJ_SUCCESS) {
+	goto on_error;
+    }
+
+    /* Register this allocation */
+    pj_turn_srv_register_allocation(srv, alloc);
+
+    /* Respond to ALLOCATE request */
+    status = send_allocate_response(alloc, srv_sess, transport, rdata);
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    /* Done */
+    pj_sockaddr_print(&alloc->relay.hkey.addr, str_tmp, 
+		      sizeof(str_tmp), 3);
+    PJ_LOG(4,(alloc->obj_name, "Client %s created, relay addr=%s:%s", 
+	      alloc->info, pj_turn_tp_type_name(req.tp_type), str_tmp));
+
+    /* Success */
+    *p_alloc = alloc;
+    return PJ_SUCCESS;
+
+on_error:
+    /* Send reply to the ALLOCATE request */
+    pj_strerror(status, str_tmp, sizeof(str_tmp));
+    pj_stun_session_respond(srv_sess, rdata, PJ_STUN_SC_BAD_REQUEST, str_tmp, 
+			    transport, PJ_TRUE, src_addr, src_addr_len);
+
+    /* Cleanup */
+    destroy_allocation(alloc);
+    return status;
+}
+
+
+/* Destroy relay resource */
+static void destroy_relay(pj_turn_relay_res *relay)
+{
+    if (relay->timer.id) {
+	pj_timer_heap_cancel(relay->allocation->server->core.timer_heap, 
+			     &relay->timer);
+	relay->timer.id = PJ_FALSE;
+    }
+
+    if (relay->tp.key) {
+	pj_ioqueue_unregister(relay->tp.key);
+	relay->tp.key = NULL;
+	relay->tp.sock = PJ_INVALID_SOCKET;
+    } else if (relay->tp.sock != PJ_INVALID_SOCKET) {
+	pj_sock_close(relay->tp.sock);
+	relay->tp.sock = PJ_INVALID_SOCKET;
+    }
+
+    /* Mark as shutdown */
+    relay->lifetime = 0;
+}
+
+
+/*
+ * Really destroy allocation.
+ */
+static void destroy_allocation(pj_turn_allocation *alloc)
+{
+    pj_pool_t *pool;
+
+    /* Unregister this allocation */
+    pj_turn_srv_unregister_allocation(alloc->server, alloc);
+
+    /* Destroy relay */
+    destroy_relay(&alloc->relay);
+
+    /* Must lock only after destroying relay otherwise deadlock */
+    if (alloc->lock) {
+	pj_lock_acquire(alloc->lock);
+    }
+
+    /* Unreference transport */
+    if (alloc->transport) {
+	pj_turn_transport_dec_ref(alloc->transport, alloc);
+	alloc->transport = NULL;
+    }
+
+    /* Destroy STUN session */
+    if (alloc->sess) {
+	pj_stun_session_destroy(alloc->sess);
+	alloc->sess = NULL;
+    }
+
+    /* Destroy lock */
+    if (alloc->lock) {
+	pj_lock_release(alloc->lock);
+	pj_lock_destroy(alloc->lock);
+	alloc->lock = NULL;
+    }
+
+    /* Destroy pool */
+    pool = alloc->pool;
+    if (pool) {
+	alloc->pool = NULL;
+	pj_pool_release(pool);
+    }
+}
+
+
+PJ_DECL(void) pj_turn_allocation_destroy(pj_turn_allocation *alloc)
+{
+    destroy_allocation(alloc);
+}
+
+
+/*
+ * Handle transport closure.
+ */
+PJ_DEF(void) pj_turn_allocation_on_transport_closed( pj_turn_allocation *alloc,
+						     pj_turn_transport *tp)
+{
+    PJ_LOG(5,(alloc->obj_name, "Transport %s unexpectedly closed, destroying "
+	      "allocation %s", tp->info, alloc->info));
+    pj_turn_transport_dec_ref(tp, alloc);
+    alloc->transport = NULL;
+    destroy_allocation(alloc);
+}
+
+
+/* Initiate shutdown sequence for this allocation and start destroy timer.
+ * Once allocation is marked as shutting down, any packets will be 
+ * rejected/discarded 
+ */
+static void alloc_shutdown(pj_turn_allocation *alloc)
+{
+    pj_time_val destroy_delay = DESTROY_DELAY;
+
+    /* Work with existing schedule */
+    if (alloc->relay.timer.id == TIMER_ID_TIMEOUT) {
+	/* Cancel existing shutdown timer */
+	pj_timer_heap_cancel(alloc->server->core.timer_heap,
+			     &alloc->relay.timer);
+	alloc->relay.timer.id = TIMER_ID_NONE;
+
+    } else if (alloc->relay.timer.id == TIMER_ID_DESTROY) {
+	/* We've been scheduled to be destroyed, ignore this
+	 * shutdown request.
+	 */
+	return;
+    } 
+
+    pj_assert(alloc->relay.timer.id == TIMER_ID_NONE);
+
+    /* Shutdown relay socket */
+    destroy_relay(&alloc->relay);
+
+    /* Don't unregister from hash table because we still need to
+     * handle REFRESH retransmission.
+     */
+
+    /* Schedule destroy timer */
+    alloc->relay.timer.id = TIMER_ID_DESTROY;
+    pj_timer_heap_schedule(alloc->server->core.timer_heap,
+			   &alloc->relay.timer, &destroy_delay);
+}
+
+
+/* Reschedule timeout using current lifetime setting */
+static pj_status_t resched_timeout(pj_turn_allocation *alloc)
+{
+    pj_time_val delay;
+    pj_status_t status;
+
+    pj_gettimeofday(&alloc->relay.expiry);
+    alloc->relay.expiry.sec += alloc->relay.lifetime;
+
+    pj_assert(alloc->relay.timer.id != TIMER_ID_DESTROY);
+    if (alloc->relay.timer.id != 0) {
+	pj_timer_heap_cancel(alloc->server->core.timer_heap, 
+			     &alloc->relay.timer);
+	alloc->relay.timer.id = TIMER_ID_NONE;
+    }
+
+    delay.sec = alloc->relay.lifetime;
+    delay.msec = 0;
+
+    alloc->relay.timer.id = TIMER_ID_TIMEOUT;
+    status = pj_timer_heap_schedule(alloc->server->core.timer_heap, 
+				    &alloc->relay.timer, &delay);
+    if (status != PJ_SUCCESS) {
+	alloc->relay.timer.id = TIMER_ID_NONE;
+	return status;
+    }
+
+    return PJ_SUCCESS;
+}
+
+
+/* Timer timeout callback */
+static void relay_timeout_cb(pj_timer_heap_t *heap, pj_timer_entry *e)
+{
+    pj_turn_relay_res *rel;
+    pj_turn_allocation *alloc;
+
+    PJ_UNUSED_ARG(heap);
+
+    rel = (pj_turn_relay_res*) e->user_data;
+    alloc = rel->allocation;
+
+    if (e->id == TIMER_ID_TIMEOUT) {
+
+	e->id = TIMER_ID_NONE;
+
+	PJ_LOG(4,(alloc->obj_name, 
+		  "Client %s refresh timed-out, shutting down..", 
+		  alloc->info));
+
+	alloc_shutdown(alloc);
+
+    } else if (e->id == TIMER_ID_DESTROY) {
+	e->id = TIMER_ID_NONE;
+
+	PJ_LOG(4,(alloc->obj_name, "Client %s destroying..", 
+		  alloc->info));
+
+	destroy_allocation(alloc);
+    }
+}
+
+
+/*
+ * Create relay.
+ */
+static pj_status_t create_relay(pj_turn_srv *srv,
+				pj_turn_allocation *alloc,
+				const pj_stun_msg *msg,
+				const alloc_request *req,
+				pj_turn_relay_res *relay)
+{
+    enum { RETRY = 40 };
+    pj_pool_t *pool = alloc->pool;
+    int retry, retry_max, sock_type;
+    pj_ioqueue_callback icb;
+    int af, namelen;
+    pj_stun_string_attr *sa;
+    pj_status_t status;
+
+    pj_bzero(relay, sizeof(*relay));
+    
+    relay->allocation = alloc;
+    relay->tp.sock = PJ_INVALID_SOCKET;
+    
+    /* TODO: get the requested address family from somewhere */
+    af = alloc->transport->listener->addr.addr.sa_family;
+
+    /* Save realm */
+    sa = (pj_stun_string_attr*)
+	 pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_REALM, 0);
+    PJ_ASSERT_RETURN(sa, PJ_EINVALIDOP);
+    pj_strdup(pool, &relay->realm, &sa->value);
+
+    /* Save username */
+    sa = (pj_stun_string_attr*)
+	 pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_USERNAME, 0);
+    PJ_ASSERT_RETURN(sa, PJ_EINVALIDOP);
+    pj_strdup(pool, &relay->user, &sa->value);
+
+    /* Lifetime and timeout */
+    relay->lifetime = req->lifetime;
+    pj_timer_entry_init(&relay->timer, TIMER_ID_NONE, relay, 
+			&relay_timeout_cb);
+    resched_timeout(alloc);
+    
+    /* Transport type */
+    relay->hkey.tp_type = req->tp_type;
+
+    /* Create the socket */
+    if (req->tp_type == PJ_TURN_TP_UDP) {
+	sock_type = pj_SOCK_DGRAM();
+    } else if (req->tp_type == PJ_TURN_TP_TCP) {
+	sock_type = pj_SOCK_STREAM();
+    } else {
+	pj_assert(!"Unknown transport");
+	return PJ_EINVALIDOP;
+    }
+
+    status = pj_sock_socket(af, sock_type, 0, &relay->tp.sock);
+    if (status != PJ_SUCCESS) {
+	pj_bzero(relay, sizeof(*relay));
+	return status;
+    }
+
+    /* Find suitable port for this allocation */
+    if (req->rpp_port) {
+	retry_max = 1;
+    } else {
+	retry_max = RETRY;
+    }
+
+    for (retry=0; retry<retry_max; ++retry) {
+	pj_uint16_t port;
+	pj_sockaddr bound_addr;
+
+	pj_lock_acquire(srv->core.lock);
+
+	if (req->rpp_port) {
+	    port = (pj_uint16_t) req->rpp_port;
+	} else if (req->tp_type == PJ_TURN_TP_UDP) {
+	    port = (pj_uint16_t) srv->ports.next_udp++;
+	    if (srv->ports.next_udp > srv->ports.max_udp)
+		srv->ports.next_udp = srv->ports.min_udp;
+	} else if (req->tp_type == PJ_TURN_TP_TCP) {
+	    port = (pj_uint16_t) srv->ports.next_tcp++;
+	    if (srv->ports.next_tcp > srv->ports.max_tcp)
+		srv->ports.next_tcp = srv->ports.min_tcp;
+	} else {
+	    pj_assert(!"Invalid transport");
+	    port = 0;
+	}
+
+	pj_lock_release(srv->core.lock);
+
+	pj_sockaddr_init(af, &bound_addr, NULL, port);
+
+	status = pj_sock_bind(relay->tp.sock, &bound_addr, 
+			      pj_sockaddr_get_len(&bound_addr));
+	if (status == PJ_SUCCESS)
+	    break;
+    }
+
+    if (status != PJ_SUCCESS) {
+	/* Unable to allocate port */
+	PJ_LOG(4,(THIS_FILE, "Unable to allocate relay, giving up: err %d", 
+		  status));
+	pj_sock_close(relay->tp.sock);
+	relay->tp.sock = PJ_INVALID_SOCKET;
+	return status;
+    }
+
+    /* Init relay key */
+    namelen = sizeof(relay->hkey.addr);
+    status = pj_sock_getsockname(relay->tp.sock, &relay->hkey.addr, &namelen);
+    if (status != PJ_SUCCESS) {
+	PJ_LOG(4,(THIS_FILE, "pj_sock_getsockname() failed: err %d", 
+		  status));
+	pj_sock_close(relay->tp.sock);
+	relay->tp.sock = PJ_INVALID_SOCKET;
+	return status;
+    }
+    if (!pj_sockaddr_has_addr(&relay->hkey.addr)) {
+	pj_sockaddr_copy_addr(&relay->hkey.addr, 
+			      &alloc->transport->listener->addr);
+    }
+    if (!pj_sockaddr_has_addr(&relay->hkey.addr)) {
+	pj_sockaddr tmp_addr;
+	pj_gethostip(af, &tmp_addr);
+	pj_sockaddr_copy_addr(&relay->hkey.addr, &tmp_addr);
+    }
+
+    /* Init ioqueue */
+    pj_bzero(&icb, sizeof(icb));
+    icb.on_read_complete = &on_rx_from_peer;
+
+    status = pj_ioqueue_register_sock(pool, srv->core.ioqueue, relay->tp.sock,
+				      relay, &icb, &relay->tp.key);
+    if (status != PJ_SUCCESS) {
+	PJ_LOG(4,(THIS_FILE, "pj_ioqueue_register_sock() failed: err %d", 
+		  status));
+	pj_sock_close(relay->tp.sock);
+	relay->tp.sock = PJ_INVALID_SOCKET;
+	return status;
+    }
+
+    /* Kick off pending read operation */
+    pj_ioqueue_op_key_init(&relay->tp.read_key, sizeof(relay->tp.read_key));
+    on_rx_from_peer(relay->tp.key, &relay->tp.read_key, 0);
+
+    /* Done */
+    return PJ_SUCCESS;
+}
+
+/* Create and send error response */
+static void send_reply_err(pj_turn_allocation *alloc,
+			   const pj_stun_rx_data *rdata,
+			   pj_bool_t cache, 
+			   int code, const char *errmsg)
+{
+    pj_status_t status;
+
+    status = pj_stun_session_respond(alloc->sess, rdata, code, errmsg, NULL, 
+				     cache, &alloc->hkey.clt_addr,
+				     pj_sockaddr_get_len(&alloc->hkey.clt_addr.addr));
+    if (status != PJ_SUCCESS) {
+	alloc_err(alloc, "Error sending STUN error response", status);
+	return;
+    }
+}
+
+/* Create and send successful response */
+static void send_reply_ok(pj_turn_allocation *alloc,
+		          const pj_stun_rx_data *rdata)
+{
+    pj_status_t status;
+    unsigned interval;
+    pj_stun_tx_data *tdata;
+
+    status = pj_stun_session_create_res(alloc->sess, rdata, 0, NULL, &tdata);
+    if (status != PJ_SUCCESS) {
+	alloc_err(alloc, "Error creating STUN success response", status);
+	return;
+    }
+
+    /* Calculate time to expiration */
+    if (alloc->relay.lifetime != 0) {
+	pj_time_val now;
+	pj_gettimeofday(&now);
+	interval = alloc->relay.expiry.sec - now.sec;
+    } else {
+	interval = 0;
+    }
+
+    /* Add LIFETIME if this is not ChannelBind. */
+    if (PJ_STUN_GET_METHOD(tdata->msg->hdr.type)!=PJ_STUN_CHANNEL_BIND_METHOD){
+	pj_stun_msg_add_uint_attr(tdata->pool, tdata->msg,
+				  PJ_STUN_ATTR_LIFETIME, interval);
+
+	/* Add BANDWIDTH if lifetime is not zero */
+	if (interval != 0) {
+	    pj_stun_msg_add_uint_attr(tdata->pool, tdata->msg,
+				      PJ_STUN_ATTR_BANDWIDTH,
+				      alloc->bandwidth);
+	}
+    }
+
+    status = pj_stun_session_send_msg(alloc->sess, NULL, PJ_TRUE, 
+				      PJ_FALSE, &alloc->hkey.clt_addr,  
+				      pj_sockaddr_get_len(&alloc->hkey.clt_addr), 
+				      tdata);
+    if (status != PJ_SUCCESS) {
+	alloc_err(alloc, "Error sending STUN success response", status);
+	return;
+    }
+}
+
+
+/* Create new permission */
+static pj_turn_permission *create_permission(pj_turn_allocation *alloc,
+					     const pj_sockaddr_t *peer_addr,
+					     unsigned addr_len)
+{
+    pj_turn_permission *perm;
+
+    perm = PJ_POOL_ZALLOC_T(alloc->pool, pj_turn_permission);
+    pj_memcpy(&perm->hkey.peer_addr, peer_addr, addr_len);
+    
+    perm->allocation = alloc;
+    perm->channel = PJ_TURN_INVALID_CHANNEL;
+
+    pj_gettimeofday(&perm->expiry);
+    perm->expiry.sec += PJ_TURN_PERM_TIMEOUT;
+
+    /* Register to hash table (only the address part!) */
+    pj_hash_set(alloc->pool, alloc->peer_table, 
+		pj_sockaddr_get_addr(&perm->hkey.peer_addr), 
+	        pj_sockaddr_get_addr_len(&perm->hkey.peer_addr), 0, perm);
+
+    return perm;
+}
+
+/* Check if a permission isn't expired. Return NULL if expired. */
+static pj_turn_permission *check_permission_expiry(pj_turn_permission *perm)
+{
+    pj_turn_allocation *alloc = perm->allocation;
+    pj_time_val now;
+
+    pj_gettimeofday(&now);
+    if (PJ_TIME_VAL_GT(perm->expiry, now)) {
+	/* Permission has not expired */
+	return perm;
+    }
+
+    /* Remove from permission hash table */
+    pj_hash_set(NULL, alloc->peer_table, 
+		pj_sockaddr_get_addr(&perm->hkey.peer_addr), 
+	        pj_sockaddr_get_addr_len(&perm->hkey.peer_addr), 0, NULL);
+
+    /* Remove from channel hash table, if assigned a channel number */
+    if (perm->channel != PJ_TURN_INVALID_CHANNEL) {
+	pj_hash_set(NULL, alloc->ch_table, &perm->channel, 
+		    sizeof(perm->channel), 0, NULL);
+    }
+
+    return NULL;
+}
+
+/* Lookup permission in hash table by the peer address */
+static pj_turn_permission*
+lookup_permission_by_addr(pj_turn_allocation *alloc,
+			  const pj_sockaddr_t *peer_addr,
+			  unsigned addr_len)
+{
+    pj_turn_permission *perm;
+
+    PJ_UNUSED_ARG(addr_len);
+
+    /* Lookup in peer hash table */
+    perm = (pj_turn_permission*) 
+	   pj_hash_get(alloc->peer_table, 
+		       pj_sockaddr_get_addr(peer_addr),
+		       pj_sockaddr_get_addr_len(peer_addr), 
+		       NULL);
+    return perm ? check_permission_expiry(perm) : NULL;
+}
+
+/* Lookup permission in hash table by the channel number */
+static pj_turn_permission*
+lookup_permission_by_chnum(pj_turn_allocation *alloc,
+			   unsigned chnum)
+{
+    pj_uint16_t chnum16 = (pj_uint16_t)chnum;
+    pj_turn_permission *perm;
+
+    /* Lookup in peer hash table */
+    perm = (pj_turn_permission*) pj_hash_get(alloc->ch_table, &chnum16,
+					    sizeof(chnum16), NULL);
+    return perm ? check_permission_expiry(perm) : NULL;
+}
+
+/* Update permission because of data from client to peer. 
+ * Return PJ_TRUE is permission is found.
+ */
+static pj_bool_t refresh_permission(pj_turn_permission *perm)
+{
+    pj_gettimeofday(&perm->expiry);
+    if (perm->channel == PJ_TURN_INVALID_CHANNEL)
+	perm->expiry.sec += PJ_TURN_PERM_TIMEOUT;
+    else
+	perm->expiry.sec += PJ_TURN_CHANNEL_TIMEOUT;
+    return PJ_TRUE;
+}
+
+/*
+ * Handle incoming packet from client. This would have been called by
+ * server upon receiving packet from a listener.
+ */
+PJ_DEF(void) pj_turn_allocation_on_rx_client_pkt(pj_turn_allocation *alloc,
+						 pj_turn_pkt *pkt)
+{
+    pj_bool_t is_stun;
+    pj_status_t status;
+
+    /* Lock this allocation */
+    pj_lock_acquire(alloc->lock);
+
+    /* Quickly check if this is STUN message */
+    is_stun = ((*((pj_uint8_t*)pkt->pkt) & 0xC0) == 0);
+
+    if (is_stun) {
+	/*
+	 * This could be an incoming STUN requests or indications.
+	 * Pass this through to the STUN session, which will call
+	 * our stun_on_rx_request() or stun_on_rx_indication()
+	 * callbacks.
+	 *
+	 * Note: currently it is necessary to specify the 
+	 * PJ_STUN_NO_FINGERPRINT_CHECK otherwise the FINGERPRINT
+	 * attribute inside STUN Send Indication message will mess up
+	 * with fingerprint checking.
+	 */
+	unsigned options = PJ_STUN_CHECK_PACKET | PJ_STUN_NO_FINGERPRINT_CHECK;
+	pj_size_t parsed_len = 0;
+
+	if (pkt->transport->listener->tp_type == PJ_TURN_TP_UDP)
+	    options |= PJ_STUN_IS_DATAGRAM;
+
+	status = pj_stun_session_on_rx_pkt(alloc->sess, pkt->pkt, pkt->len,
+					   options, NULL, &parsed_len,
+					   &pkt->src.clt_addr, 
+					   pkt->src_addr_len);
+
+	if (pkt->transport->listener->tp_type == PJ_TURN_TP_UDP) {
+	    pkt->len = 0;
+	} else if (parsed_len > 0) {
+	    if (parsed_len == pkt->len) {
+		pkt->len = 0;
+	    } else {
+		pj_memmove(pkt->pkt, pkt->pkt+parsed_len,
+			   pkt->len - parsed_len);
+		pkt->len -= parsed_len;
+	    }
+	}
+
+	if (status != PJ_SUCCESS) {
+	    alloc_err(alloc, "Error handling STUN packet", status);
+	    goto on_return;
+	}
+
+    } else {
+	/*
+	 * This is not a STUN packet, must be ChannelData packet.
+	 */
+	pj_turn_channel_data *cd = (pj_turn_channel_data*)pkt->pkt;
+	pj_turn_permission *perm;
+	pj_ssize_t len;
+
+	pj_assert(sizeof(*cd)==4);
+
+	/* For UDP check the packet length */
+	if (alloc->transport->listener->tp_type == PJ_TURN_TP_UDP) {
+	    if (pkt->len < pj_ntohs(cd->length)+sizeof(*cd)) {
+		PJ_LOG(4,(alloc->obj_name, 
+			  "ChannelData from %s discarded: UDP size error",
+			  alloc->info));
+		goto on_return;
+	    }
+	} else {
+	    pj_assert(!"Unsupported transport");
+	    goto on_return;
+	}
+
+	perm = lookup_permission_by_chnum(alloc, pj_ntohs(cd->ch_number));
+	if (!perm) {
+	    /* Discard */
+	    PJ_LOG(4,(alloc->obj_name, 
+		      "ChannelData from %s discarded: ch#0x%x not found",
+		      alloc->info, pj_ntohs(cd->ch_number)));
+	    goto on_return;
+	}
+
+	/* Relay the data */
+	len = pj_ntohs(cd->length);
+	pj_sock_sendto(alloc->relay.tp.sock, cd+1, &len, 0,
+		       &perm->hkey.peer_addr,
+		       pj_sockaddr_get_len(&perm->hkey.peer_addr));
+
+	/* Refresh permission */
+	refresh_permission(perm);
+    }
+
+on_return:
+    /* Release lock */
+    pj_lock_release(alloc->lock);
+}
+
+
+/*
+ * Handle incoming packet from peer. This function is called by 
+ * on_rx_from_peer().
+ */
+static void handle_peer_pkt(pj_turn_allocation *alloc,
+			    pj_turn_relay_res *rel,
+			    char *pkt, pj_size_t len,
+			    const pj_sockaddr *src_addr)
+{
+    pj_turn_permission *perm;
+
+    /* Lookup permission */
+    perm = lookup_permission_by_addr(alloc, src_addr, 
+				     pj_sockaddr_get_len(src_addr));
+    if (perm == NULL) {
+	/* No permission, discard data */
+	return;
+    }
+
+    /* Send Data Indication or ChannelData, depends on whether
+     * this permission is attached to a channel number.
+     */
+    if (perm->channel != PJ_TURN_INVALID_CHANNEL) {
+	/* Send ChannelData */
+	pj_turn_channel_data *cd = (pj_turn_channel_data*)rel->tp.tx_pkt;
+
+	if (len > PJ_TURN_MAX_PKT_LEN) {
+	    char peer_addr[80];
+	    pj_sockaddr_print(src_addr, peer_addr, sizeof(peer_addr), 3);
+	    PJ_LOG(4,(alloc->obj_name, "Client %s: discarded data from %s "
+		      "because it's too long (%d bytes)",
+		      alloc->info, peer_addr, len));
+	    return;
+	}
+
+	/* Init header */
+	cd->ch_number = pj_htons(perm->channel);
+	cd->length = pj_htons((pj_uint16_t)len);
+
+	/* Copy data */
+	pj_memcpy(rel->tp.tx_pkt+sizeof(pj_turn_channel_data), pkt, len);
+
+	/* Send to client */
+	alloc->transport->sendto(alloc->transport, rel->tp.tx_pkt,
+			         len+sizeof(pj_turn_channel_data), 0,
+			         &alloc->hkey.clt_addr,
+			         pj_sockaddr_get_len(&alloc->hkey.clt_addr));
+    } else {
+	/* Send Data Indication */
+	pj_stun_tx_data *tdata;
+	pj_status_t status;
+
+	status = pj_stun_session_create_ind(alloc->sess, 
+					    PJ_STUN_DATA_INDICATION, &tdata);
+	if (status != PJ_SUCCESS) {
+	    alloc_err(alloc, "Error creating Data indication", status);
+	    return;
+	}
+
+	pj_stun_msg_add_sockaddr_attr(tdata->pool, tdata->msg, 
+				      PJ_STUN_ATTR_XOR_PEER_ADDR, PJ_TRUE,
+				      src_addr, pj_sockaddr_get_len(src_addr));
+	pj_stun_msg_add_binary_attr(tdata->pool, tdata->msg,
+				    PJ_STUN_ATTR_DATA, 
+				    (const pj_uint8_t*)pkt, len);
+
+	pj_stun_session_send_msg(alloc->sess, NULL, PJ_FALSE, 
+				 PJ_FALSE, &alloc->hkey.clt_addr, 
+				 pj_sockaddr_get_len(&alloc->hkey.clt_addr), 
+				 tdata);
+    }
+}
+
+/*
+ * ioqueue notification on RX packets from the relay socket.
+ */
+static void on_rx_from_peer(pj_ioqueue_key_t *key, 
+                            pj_ioqueue_op_key_t *op_key, 
+                            pj_ssize_t bytes_read)
+{
+    pj_turn_relay_res *rel;
+    pj_status_t status;
+
+    rel = (pj_turn_relay_res*) pj_ioqueue_get_user_data(key);
+
+    /* Lock the allocation */
+    pj_lock_acquire(rel->allocation->lock);
+
+    do {
+	if (bytes_read > 0) {
+	    handle_peer_pkt(rel->allocation, rel, rel->tp.rx_pkt,
+			    bytes_read, &rel->tp.src_addr);
+	}
+
+	/* Read next packet */
+	bytes_read = sizeof(rel->tp.rx_pkt);
+	rel->tp.src_addr_len = sizeof(rel->tp.src_addr);
+	status = pj_ioqueue_recvfrom(key, op_key,
+				     rel->tp.rx_pkt, &bytes_read, 0,
+				     &rel->tp.src_addr, 
+				     &rel->tp.src_addr_len);
+
+	if (status != PJ_EPENDING && status != PJ_SUCCESS)
+	    bytes_read = -status;
+
+    } while (status != PJ_EPENDING && status != PJ_ECANCELLED);
+
+    /* Release allocation lock */
+    pj_lock_release(rel->allocation->lock);
+}
+
+/*
+ * Callback notification from STUN session when it wants to send
+ * a STUN message towards the client.
+ */
+static pj_status_t stun_on_send_msg(pj_stun_session *sess,
+				    void *token,
+				    const void *pkt,
+				    pj_size_t pkt_size,
+				    const pj_sockaddr_t *dst_addr,
+				    unsigned addr_len)
+{
+    pj_turn_allocation *alloc;
+
+    PJ_UNUSED_ARG(token);
+
+    alloc = (pj_turn_allocation*) pj_stun_session_get_user_data(sess);
+
+    return alloc->transport->sendto(alloc->transport, pkt, pkt_size, 0,
+				    dst_addr, addr_len);
+}
+
+/*
+ * Callback notification from STUN session when it receives STUN
+ * requests. This callback was trigger by STUN incoming message
+ * processing in pj_turn_allocation_on_rx_client_pkt().
+ */
+static pj_status_t stun_on_rx_request(pj_stun_session *sess,
+				      const pj_uint8_t *pkt,
+				      unsigned pkt_len,
+				      const pj_stun_rx_data *rdata,
+				      void *token,
+				      const pj_sockaddr_t *src_addr,
+				      unsigned src_addr_len)
+{
+    const pj_stun_msg *msg = rdata->msg;
+    pj_turn_allocation *alloc;
+
+    PJ_UNUSED_ARG(pkt);
+    PJ_UNUSED_ARG(pkt_len);
+    PJ_UNUSED_ARG(token);
+    PJ_UNUSED_ARG(src_addr);
+    PJ_UNUSED_ARG(src_addr_len);
+
+    alloc = (pj_turn_allocation*) pj_stun_session_get_user_data(sess);
+
+    /* Refuse to serve any request if we've been shutdown */
+    if (alloc->relay.lifetime == 0) {
+	/* Reject with 437 if we're shutting down */
+	send_reply_err(alloc, rdata, PJ_TRUE, 
+		       PJ_STUN_SC_ALLOCATION_MISMATCH, NULL);
+	return PJ_SUCCESS;
+    }
+
+    if (msg->hdr.type == PJ_STUN_REFRESH_REQUEST) {
+	/* 
+	 * Handle REFRESH request 
+	 */
+	pj_stun_lifetime_attr *lifetime;
+	pj_stun_bandwidth_attr *bandwidth;
+
+	/* Get LIFETIME attribute */
+	lifetime = (pj_stun_lifetime_attr*)
+		   pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_LIFETIME, 0);
+
+	/* Get BANDWIDTH attribute */
+	bandwidth = (pj_stun_bandwidth_attr*)
+	            pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_BANDWIDTH, 0);
+
+	if (lifetime && lifetime->value==0) {
+	    /*
+	     * This is deallocation request.
+	     */
+	    alloc->relay.lifetime = 0;
+
+	    /* Respond first */
+	    send_reply_ok(alloc, rdata);
+
+	    /* Shutdown allocation */
+	    PJ_LOG(4,(alloc->obj_name, 
+		      "Client %s request to dealloc, shutting down",
+		      alloc->info));
+
+	    alloc_shutdown(alloc);
+
+	} else {
+	    /*
+	     * This is a refresh request.
+	     */
+	    
+	    /* Update lifetime */
+	    if (lifetime) {
+		alloc->relay.lifetime = lifetime->value;
+	    }
+
+	    /* Update bandwidth */
+	    // TODO:
+
+	    /* Update expiration timer */
+	    resched_timeout(alloc);
+
+	    /* Send reply */
+	    send_reply_ok(alloc, rdata);
+	}
+
+    } else if (msg->hdr.type == PJ_STUN_CHANNEL_BIND_REQUEST) {
+	/*
+	 * ChannelBind request.
+	 */
+	pj_stun_channel_number_attr *ch_attr;
+	pj_stun_xor_peer_addr_attr *peer_attr;
+	pj_turn_permission *p1, *p2;
+
+	ch_attr = (pj_stun_channel_number_attr*)
+		  pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_CHANNEL_NUMBER, 0);
+	peer_attr = (pj_stun_xor_peer_addr_attr*)
+		    pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_XOR_PEER_ADDR, 0);
+
+	if (!ch_attr || !peer_attr) {
+	    send_reply_err(alloc, rdata, PJ_TRUE, 
+			   PJ_STUN_SC_BAD_REQUEST, NULL);
+	    return PJ_SUCCESS;
+	}
+
+	/* Find permission with the channel number */
+	p1 = lookup_permission_by_chnum(alloc, PJ_STUN_GET_CH_NB(ch_attr->value));
+
+	/* If permission is found, this is supposed to be a channel bind 
+	 * refresh. Make sure it's for the same peer.
+	 */
+	if (p1) {
+	    if (pj_sockaddr_cmp(&p1->hkey.peer_addr, &peer_attr->sockaddr)) {
+		/* Address mismatch. Send 400 */
+		send_reply_err(alloc, rdata, PJ_TRUE, 
+			       PJ_STUN_SC_BAD_REQUEST, 
+			       "Peer address mismatch");
+		return PJ_SUCCESS;
+	    }
+
+	    /* Refresh permission */
+	    refresh_permission(p1);
+
+	    /* Send response */
+	    send_reply_ok(alloc, rdata);
+
+	    /* Done */
+	    return PJ_SUCCESS;
+	}
+
+	/* If permission is not found, create a new one. Make sure the peer
+	 * has not alreadyy assigned with a channel number.
+	 */
+	p2 = lookup_permission_by_addr(alloc, &peer_attr->sockaddr,
+				       pj_sockaddr_get_len(&peer_attr->sockaddr));
+	if (p2 && p2->channel != PJ_TURN_INVALID_CHANNEL) {
+	    send_reply_err(alloc, rdata, PJ_TRUE, PJ_STUN_SC_BAD_REQUEST, 
+			   "Peer address already assigned a channel number");
+	    return PJ_SUCCESS;
+	}
+
+	/* Create permission if it doesn't exist */
+	if (!p2) {
+	    p2 = create_permission(alloc, &peer_attr->sockaddr,
+				   pj_sockaddr_get_len(&peer_attr->sockaddr));
+	    if (!p2)
+		return PJ_SUCCESS;
+	}
+
+	/* Assign channel number to permission */
+	p2->channel = PJ_STUN_GET_CH_NB(ch_attr->value);
+
+	/* Register to hash table */
+	pj_assert(sizeof(p2->channel==2));
+	pj_hash_set(alloc->pool, alloc->ch_table, &p2->channel, 
+		    sizeof(p2->channel), 0, p2);
+
+	/* Update */
+	refresh_permission(p2);
+
+	/* Reply */
+	send_reply_ok(alloc, rdata);
+
+	return PJ_SUCCESS;
+
+    } else if (msg->hdr.type == PJ_STUN_ALLOCATE_REQUEST) {
+
+	/* Respond with 437 (section 6.3 turn-07) */
+	send_reply_err(alloc, rdata, PJ_TRUE, PJ_STUN_SC_ALLOCATION_MISMATCH,
+		       NULL);
+
+    } else {
+
+	/* Respond with Bad Request? */
+	send_reply_err(alloc, rdata, PJ_TRUE, PJ_STUN_SC_BAD_REQUEST, NULL);
+
+    }
+
+    return PJ_SUCCESS;
+}
+
+/*
+ * Callback notification from STUN session when it receives STUN
+ * indications. This callback was trigger by STUN incoming message
+ * processing in pj_turn_allocation_on_rx_client_pkt().
+ */
+static pj_status_t stun_on_rx_indication(pj_stun_session *sess,
+					 const pj_uint8_t *pkt,
+					 unsigned pkt_len,
+					 const pj_stun_msg *msg,
+					 void *token,
+					 const pj_sockaddr_t *src_addr,
+					 unsigned src_addr_len)
+{
+    pj_stun_xor_peer_addr_attr *peer_attr;
+    pj_stun_data_attr *data_attr;
+    pj_turn_allocation *alloc;
+    pj_turn_permission *perm;
+    pj_ssize_t len;
+
+    PJ_UNUSED_ARG(pkt);
+    PJ_UNUSED_ARG(pkt_len);
+    PJ_UNUSED_ARG(token);
+    PJ_UNUSED_ARG(src_addr);
+    PJ_UNUSED_ARG(src_addr_len);
+
+    alloc = (pj_turn_allocation*) pj_stun_session_get_user_data(sess);
+
+    /* Only expect Send Indication */
+    if (msg->hdr.type != PJ_STUN_SEND_INDICATION) {
+	/* Ignore */
+	return PJ_SUCCESS;
+    }
+
+    /* Get XOR-PEER-ADDRESS attribute */
+    peer_attr = (pj_stun_xor_peer_addr_attr*)
+		pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_XOR_PEER_ADDR, 0);
+
+    /* MUST have XOR-PEER-ADDRESS attribute */
+    if (!peer_attr)
+	return PJ_SUCCESS;
+
+    /* Get DATA attribute */
+    data_attr = (pj_stun_data_attr*)
+		pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_DATA, 0);
+
+    /* Create/update/refresh the permission */
+    perm = lookup_permission_by_addr(alloc, &peer_attr->sockaddr,
+				     pj_sockaddr_get_len(&peer_attr->sockaddr));
+    if (perm == NULL) {
+	perm = create_permission(alloc, &peer_attr->sockaddr,
+				 pj_sockaddr_get_len(&peer_attr->sockaddr));
+    }
+    refresh_permission(perm);
+
+    /* Return if we don't have data */
+    if (data_attr == NULL)
+	return PJ_SUCCESS;
+
+    /* Relay the data to peer */
+    len = data_attr->length;
+    pj_sock_sendto(alloc->relay.tp.sock, data_attr->data, 
+		   &len, 0, &peer_attr->sockaddr,
+		   pj_sockaddr_get_len(&peer_attr->sockaddr));
+
+    return PJ_SUCCESS;
+}
+
+