Changeset 1988 for pjproject/trunk/pjnath/src/pjnath/ice_strans.c

Timestamp:

Jun 6, 2008 2:47:10 PM (16 years ago)

Author:

bennylp

Message:

Major major modifications related to ticket #485 (support for TURN-07):

• Added STUN socket transport pj_stun_sock
• Integration of TURN-07 to ICE
• Major refactoring in ICE stream transport to make it simpler
• Major modification (i.e. API change) in almost everywhere else
• Much more elaborate STUN, TURN, and ICE tests in pjnath-test

File:

• pjproject/trunk/pjnath/src/pjnath/ice_strans.c (modified) (23 diffs)

pjproject/trunk/pjnath/src/pjnath/ice_strans.c

@@ -20 +20 @@
 #include <pjnath/errno.h>
 #include <pj/addr_resolv.h>
+#include <pj/array.h>
 #include <pj/assert.h>
 #include <pj/ip_helper.h>
 #include <pj/log.h>
+#include <pj/os.h>
 #include <pj/pool.h>
 #include <pj/rand.h>
@@ -36 +38 @@
 
 
+/* Transport IDs */
+enum tp_type
+{
+    TP_NONE,
+    TP_STUN,
+    TP_TURN
+};
+
+/* Candidate preference default values */
+#define SRFLX_PREF  65535
+#define HOST_PREF   65530
+#define RELAY_PREF  65525
+
 
 /* ICE callbacks */
@@ -41 +56 @@
 static pj_status_t ice_tx_pkt(pj_ice_sess *ice, 
                               unsigned comp_id,
+                              unsigned transport_id,
                               const void *pkt, pj_size_t size,
                               const pj_sockaddr_t *dst_addr,
                               unsigned dst_addr_len);
 static void        ice_rx_data(pj_ice_sess *ice, 
-                              unsigned comp_id, 
-                              void *pkt, pj_size_t size,
-                              const pj_sockaddr_t *src_addr,
-                              unsigned src_addr_len);
-
-/* Ioqueue callback */
-static void on_read_complete(pj_ioqueue_key_t *key, 
-                             pj_ioqueue_op_key_t *op_key, 
-                             pj_ssize_t bytes_read);
-
-static void destroy_component(pj_ice_strans_comp *comp);
-static void destroy_ice_st(pj_ice_strans *ice_st, pj_status_t reason);
-
-
-/* STUN session callback */
-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 void stun_on_request_complete(pj_stun_session *sess,
-                                     pj_status_t status,
-                                     void *token,
-                                     pj_stun_tx_data *tdata,
-                                     const pj_stun_msg *response,
-                                     const pj_sockaddr_t *src_addr,
-                                     unsigned src_addr_len);
-
-/* Keep-alive timer */
-static void start_ka_timer(pj_ice_strans *ice_st);
-static void stop_ka_timer(pj_ice_strans *ice_st);
-
-/* Utility: print error */
+                               unsigned comp_id, 
+                               unsigned transport_id,
+                               void *pkt, pj_size_t size,
+                               const pj_sockaddr_t *src_addr,
+                               unsigned src_addr_len);
+
+
+/* STUN socket callbacks */
+/* Notification when incoming packet has been received. */
+static pj_bool_t stun_on_rx_data(pj_stun_sock *stun_sock,
+                                 void *pkt,
+                                 unsigned pkt_len,
+                                 const pj_sockaddr_t *src_addr,
+                                 unsigned addr_len);
+/* Notifification when asynchronous send operation has completed. */
+static pj_bool_t stun_on_data_sent(pj_stun_sock *stun_sock,
+                                   pj_ioqueue_op_key_t *send_key,
+                                   pj_ssize_t sent);
+/* Notification when the status of the STUN transport has changed. */
+static pj_bool_t stun_on_status(pj_stun_sock *stun_sock, 
+                                pj_stun_sock_op op,
+                                pj_status_t status);
+
+
+/* TURN callbacks */
+static void turn_on_rx_data(pj_turn_sock *turn_sock,
+                            void *pkt,
+                            unsigned pkt_len,
+                            const pj_sockaddr_t *peer_addr,
+                            unsigned addr_len);
+static void turn_on_state(pj_turn_sock *turn_sock, pj_turn_state_t old_state,
+                          pj_turn_state_t new_state);
+
+
+
+/* Forward decls */
+static void destroy_ice_st(pj_ice_strans *ice_st);
 #define ice_st_perror(ice_st,msg,rc) pjnath_perror(ice_st->obj_name,msg,rc)
+static void sess_init_update(pj_ice_strans *ice_st);
+
+static void sess_add_ref(pj_ice_strans *ice_st);
+static pj_bool_t sess_dec_ref(pj_ice_strans *ice_st);
+
+/**
+ * This structure describes an ICE stream transport component. A component
+ * in ICE stream transport typically corresponds to a single socket created
+ * for this component, and bound to a specific transport address. This
+ * component may have multiple alias addresses, for example one alias 
+ * address for each interfaces in multi-homed host, another for server
+ * reflexive alias, and another for relayed alias. For each transport
+ * address alias, an ICE stream transport candidate (#pj_ice_sess_cand) will
+ * be created, and these candidates will eventually registered to the ICE
+ * session.
+ */
+typedef struct pj_ice_strans_comp
+{
+    pj_ice_strans       *ice_st;        /**< ICE stream transport.      */
+    unsigned             comp_id;       /**< Component ID.              */
+
+    pj_stun_sock        *stun_sock;     /**< STUN transport.            */
+    pj_turn_sock        *turn_sock;     /**< TURN relay transport.      */
+
+    unsigned             cand_cnt;      /**< # of candidates/aliaes.    */
+    pj_ice_sess_cand     cand_list[PJ_ICE_ST_MAX_CAND]; /**< Cand array */
+
+    unsigned             default_cand;  /**< Default candidate.         */
+
+} pj_ice_strans_comp;
+
+
+/**
+ * This structure represents the ICE stream transport.
+ */
+struct pj_ice_strans
+{
+    char                    *obj_name;  /**< Log ID.                    */
+    pj_pool_t               *pool;      /**< Pool used by this object.  */
+    void                    *user_data; /**< Application data.          */
+    pj_ice_strans_cfg        cfg;       /**< Configuration.             */
+    pj_ice_strans_cb         cb;        /**< Application callback.      */
+
+    pj_ice_sess             *ice;       /**< ICE session.               */
+    pj_time_val              start_time;/**< Time when ICE was started  */
+
+    unsigned                 comp_cnt;  /**< Number of components.      */
+    pj_ice_strans_comp     **comp;      /**< Components array.          */
+
+    pj_timer_entry           ka_timer;  /**< STUN keep-alive timer.     */
+
+    pj_atomic_t             *busy_cnt;  /**< To prevent destroy         */
+    pj_bool_t                destroy_req;/**< Destroy has been called?  */
+    pj_bool_t                cb_called; /**< Init error callback called?*/
+};
+
+
+/* Validate configuration */
+static pj_status_t pj_ice_strans_cfg_check_valid(const pj_ice_strans_cfg *cfg)
+{
+    pj_status_t status;
+
+    status = pj_stun_config_check_valid(&cfg->stun_cfg);
+    if (!status)
+        return status;
+
+    return PJ_SUCCESS;
+}
+
+
+/*
+ * Initialize ICE transport configuration with default values.
+ */
+PJ_DEF(void) pj_ice_strans_cfg_default(pj_ice_strans_cfg *cfg)
+{
+    pj_bzero(cfg, sizeof(*cfg));
+
+    pj_stun_config_init(&cfg->stun_cfg, NULL, 0, NULL, NULL);
+    pj_stun_sock_cfg_default(&cfg->stun.cfg);
+    pj_turn_alloc_param_default(&cfg->turn.alloc_param);
+
+    cfg->af = pj_AF_INET();
+    cfg->stun.port = PJ_STUN_PORT;
+    cfg->turn.conn_type = PJ_TURN_TP_UDP;
+}
+
+
+/*
+ * Copy configuration.
+ */
+PJ_DEF(void) pj_ice_strans_cfg_copy( pj_pool_t *pool,
+                                     pj_ice_strans_cfg *dst,
+                                     const pj_ice_strans_cfg *src)
+{
+    pj_memcpy(dst, src, sizeof(*src));
+
+    if (src->stun.server.slen)
+        pj_strdup(pool, &dst->stun.server, &src->stun.server);
+    if (src->turn.server.slen)
+        pj_strdup(pool, &dst->turn.server, &src->turn.server);
+    pj_stun_auth_cred_dup(pool, &dst->turn.auth_cred,
+                          &src->turn.auth_cred);
+}
+
+/*
+ * Create the component.
+ */
+static pj_status_t create_comp(pj_ice_strans *ice_st, unsigned comp_id)
+{
+    pj_ice_strans_comp *comp = NULL;
+    pj_status_t status;
+
+    /* Verify arguments */
+    PJ_ASSERT_RETURN(ice_st && comp_id, PJ_EINVAL);
+
+    /* Check that component ID present */
+    PJ_ASSERT_RETURN(comp_id <= ice_st->comp_cnt, PJNATH_EICEINCOMPID);
+
+    /* Create component */
+    comp = PJ_POOL_ZALLOC_T(ice_st->pool, pj_ice_strans_comp);
+    comp->ice_st = ice_st;
+    comp->comp_id = comp_id;
+
+    ice_st->comp[comp_id-1] = comp;
+
+    /* Initialize default candidate */
+    comp->default_cand = 0;
+
+    /* Create STUN transport if configured */
+    if (ice_st->cfg.stun.server.slen || !ice_st->cfg.stun.no_host_cands) {
+        pj_stun_sock_cb stun_sock_cb;
+        pj_ice_sess_cand *cand;
+
+        pj_bzero(&stun_sock_cb, sizeof(stun_sock_cb));
+        stun_sock_cb.on_rx_data = &stun_on_rx_data;
+        stun_sock_cb.on_status = &stun_on_status;
+        stun_sock_cb.on_data_sent = &stun_on_data_sent;
+        
+        /* Create the STUN transport */
+        status = pj_stun_sock_create(&ice_st->cfg.stun_cfg, NULL,
+                                     ice_st->cfg.af, &stun_sock_cb,
+                                     &ice_st->cfg.stun.cfg,
+                                     comp, &comp->stun_sock);
+        if (status != PJ_SUCCESS)
+            return status;
+
+        /* Start STUN Binding resolution and add srflx candidate 
+         * only if server is set 
+         */
+        if (ice_st->cfg.stun.server.slen) {
+            pj_stun_sock_info stun_sock_info;
+
+            /* Add pending job */
+            ///sess_add_ref(ice_st);
+
+            /* Start Binding resolution */
+            status = pj_stun_sock_start(comp->stun_sock, 
+                                        &ice_st->cfg.stun.server,
+                                        ice_st->cfg.stun.port, 
+                                        ice_st->cfg.resolver);
+            if (status != PJ_SUCCESS) {
+                ///sess_dec_ref(ice_st);
+                return status;
+            }
+
+            /* Enumerate addresses */
+            status = pj_stun_sock_get_info(comp->stun_sock, &stun_sock_info);
+            if (status != PJ_SUCCESS) {
+                ///sess_dec_ref(ice_st);
+                return status;
+            }
+
+            /* Add srflx candidate with pending status */
+            cand = &comp->cand_list[comp->cand_cnt++];
+            cand->type = PJ_ICE_CAND_TYPE_SRFLX;
+            cand->status = PJ_EPENDING;
+            cand->local_pref = SRFLX_PREF;
+            cand->transport_id = TP_STUN;
+            cand->comp_id = (pj_uint8_t) comp_id;
+            pj_sockaddr_cp(&cand->base_addr, &stun_sock_info.aliases[0]);
+            pj_sockaddr_cp(&cand->rel_addr, &cand->base_addr);
+            pj_ice_calc_foundation(ice_st->pool, &cand->foundation,
+                                   cand->type, &cand->base_addr);
+            PJ_LOG(4,(ice_st->obj_name, 
+                      "Comp %d: srflx candidate starts Binding discovery",
+                      comp_id));
+
+            /* Set default candidate to srflx */
+            comp->default_cand = cand - comp->cand_list;
+        }
+
+        /* Add local addresses to host candidates, unless no_host_cands
+         * flag is set.
+         */
+        if (ice_st->cfg.stun.no_host_cands == PJ_FALSE) {
+            pj_stun_sock_info stun_sock_info;
+            unsigned i;
+
+            /* Enumerate addresses */
+            status = pj_stun_sock_get_info(comp->stun_sock, &stun_sock_info);
+            if (status != PJ_SUCCESS)
+                return status;
+
+            for (i=0; i<stun_sock_info.alias_cnt; ++i) {
+                char addrinfo[PJ_INET6_ADDRSTRLEN+10];
+                const pj_sockaddr *addr = &stun_sock_info.aliases[i];
+
+                /* Leave one candidate for relay */
+                if (comp->cand_cnt >= PJ_ICE_ST_MAX_CAND-1) {
+                    PJ_LOG(4,(ice_st->obj_name, "Too many host candidates"));
+                    break;
+                }
+
+                /* Ignore loopback addresses unless cfg->stun.loop_addr 
+                 * is set 
+                 */
+                if ((pj_ntohl(addr->ipv4.sin_addr.s_addr)>>24)==127) {
+                    if (ice_st->cfg.stun.loop_addr==PJ_FALSE)
+                        continue;
+                }
+
+                cand = &comp->cand_list[comp->cand_cnt++];
+
+                cand->type = PJ_ICE_CAND_TYPE_HOST;
+                cand->status = PJ_SUCCESS;
+                cand->local_pref = HOST_PREF;
+                cand->transport_id = TP_STUN;
+                cand->comp_id = (pj_uint8_t) comp_id;
+                pj_sockaddr_cp(&cand->addr, addr);
+                pj_sockaddr_cp(&cand->base_addr, addr);
+                pj_bzero(&cand->rel_addr, sizeof(cand->rel_addr));
+                pj_ice_calc_foundation(ice_st->pool, &cand->foundation,
+                                       cand->type, &cand->base_addr);
+
+                PJ_LOG(4,(ice_st->obj_name, 
+                          "Comp %d: host candidate %s added",
+                          comp_id, pj_sockaddr_print(&cand->addr, addrinfo,
+                                                     sizeof(addrinfo), 3)));
+            }
+        }
+    }
+
+    /* Create TURN relay if configured. */
+    if (ice_st->cfg.turn.server.slen) {
+        pj_turn_sock_cb turn_sock_cb;
+        pj_ice_sess_cand *cand;
+
+        /* Init TURN socket */
+        pj_bzero(&turn_sock_cb, sizeof(turn_sock_cb));
+        turn_sock_cb.on_rx_data = &turn_on_rx_data;
+        turn_sock_cb.on_state = &turn_on_state;
+
+        status = pj_turn_sock_create(&ice_st->cfg.stun_cfg, ice_st->cfg.af,
+                                     ice_st->cfg.turn.conn_type,
+                                     &turn_sock_cb, 0, comp, 
+                                     &comp->turn_sock);
+        if (status != PJ_SUCCESS) {
+            return status;
+        }
+
+        /* Add pending job */
+        ///sess_add_ref(ice_st);
+
+        /* Start allocation */
+        status=pj_turn_sock_alloc(comp->turn_sock,  
+                                  &ice_st->cfg.turn.server,
+                                  ice_st->cfg.turn.port,
+                                  ice_st->cfg.resolver, 
+                                  &ice_st->cfg.turn.auth_cred, 
+                                  &ice_st->cfg.turn.alloc_param);
+        if (status != PJ_SUCCESS) {
+            ///sess_dec_ref(ice_st);
+            return status;
+        }
+
+        /* Add relayed candidate with pending status */
+        cand = &comp->cand_list[comp->cand_cnt++];
+        cand->type = PJ_ICE_CAND_TYPE_RELAYED;
+        cand->status = PJ_EPENDING;
+        cand->local_pref = RELAY_PREF;
+        cand->transport_id = TP_TURN;
+        cand->comp_id = (pj_uint8_t) comp_id;
+
+        PJ_LOG(4,(ice_st->obj_name, 
+                      "Comp %d: TURN relay candidate waiting for allocation",
+                      comp_id));
+
+        /* Set default candidate to relay */
+        comp->default_cand = cand - comp->cand_list;
+    }
+
+    return PJ_SUCCESS;
+}
+
 
 /* 
  * Create ICE stream transport 
  */
-PJ_DEF(pj_status_t) pj_ice_strans_create( pj_stun_config *stun_cfg,
-                                          const char *name,
+PJ_DEF(pj_status_t) pj_ice_strans_create( const char *name,
+                                          const pj_ice_strans_cfg *cfg,
                                           unsigned comp_cnt,
                                           void *user_data,
@@ -93 +406 @@
     pj_pool_t *pool;
     pj_ice_strans *ice_st;
-
-    PJ_ASSERT_RETURN(stun_cfg && comp_cnt && cb && p_ice_st, PJ_EINVAL);
-    PJ_ASSERT_RETURN(stun_cfg->ioqueue && stun_cfg->timer_heap, PJ_EINVAL);
+    unsigned i;
+    pj_status_t status;
+
+    status = pj_ice_strans_cfg_check_valid(cfg);
+    if (status != PJ_SUCCESS)
+        return status;
+
+    PJ_ASSERT_RETURN(comp_cnt && cb && p_ice_st, PJ_EINVAL);
 
     if (name == NULL)
-        name = "icstr%p";
-
-    pool = pj_pool_create(stun_cfg->pf, name, PJNATH_POOL_LEN_ICE_STRANS, 
+        name = "ice%p";
+
+    pool = pj_pool_create(cfg->stun_cfg.pf, name, PJNATH_POOL_LEN_ICE_STRANS,
                           PJNATH_POOL_INC_ICE_STRANS, NULL);
     ice_st = PJ_POOL_ZALLOC_T(pool, pj_ice_strans);
     ice_st->pool = pool;
-    pj_memcpy(ice_st->obj_name, pool->obj_name, PJ_MAX_OBJ_NAME);
+    ice_st->obj_name = pool->obj_name;
     ice_st->user_data = user_data;
+
+    PJ_LOG(4,(ice_st->obj_name, 
+              "Creating ICE stream transport with %d component(s)",
+              comp_cnt));
+
+    pj_ice_strans_cfg_copy(pool, &ice_st->cfg, cfg);
+    pj_memcpy(&ice_st->cb, cb, sizeof(*cb));
     
+    status = pj_atomic_create(pool, 0, &ice_st->busy_cnt);
+    if (status != PJ_SUCCESS) {
+        destroy_ice_st(ice_st);
+        return status;
+    }
+
     ice_st->comp_cnt = comp_cnt;
-    ice_st->comp = (pj_ice_strans_comp**) pj_pool_calloc(pool, comp_cnt, 
-                                                     sizeof(void*));
-
-    pj_memcpy(&ice_st->cb, cb, sizeof(*cb));
-    pj_memcpy(&ice_st->stun_cfg, stun_cfg, sizeof(*stun_cfg));
-
+    ice_st->comp = (pj_ice_strans_comp**) 
+                   pj_pool_calloc(pool, comp_cnt, sizeof(pj_ice_strans_comp*));
+
+    for (i=0; i<comp_cnt; ++i) {
+        status = create_comp(ice_st, i+1);
+        if (status != PJ_SUCCESS) {
+            destroy_ice_st(ice_st);
+            return status;
+        }
+    }
+
+    /* Check if all candidates are ready (this may call callback) */
+    sess_init_update(ice_st);
 
     PJ_LOG(4,(ice_st->obj_name, "ICE stream transport created"));
@@ -122 +460 @@
 
 /* Destroy ICE */
-static void destroy_ice_st(pj_ice_strans *ice_st, pj_status_t reason)
+static void destroy_ice_st(pj_ice_strans *ice_st)
 {
     unsigned i;
-    char obj_name[PJ_MAX_OBJ_NAME];
-
-    if (reason == PJ_SUCCESS) {
-        pj_memcpy(obj_name, ice_st->obj_name, PJ_MAX_OBJ_NAME);
-        PJ_LOG(4,(obj_name, "ICE stream transport shutting down"));
-    }
-
-    /* Kill keep-alive timer, if any */
-    stop_ka_timer(ice_st);
 
     /* Destroy ICE if we have ICE */
@@ -144 +473 @@
     for (i=0; i<ice_st->comp_cnt; ++i) {
         if (ice_st->comp[i]) {
-            destroy_component(ice_st->comp[i]);
-            ice_st->comp[i] = NULL;
+            if (ice_st->comp[i]->stun_sock) {
+                pj_stun_sock_set_user_data(ice_st->comp[i]->stun_sock, NULL);
+                pj_stun_sock_destroy(ice_st->comp[i]->stun_sock);
+                ice_st->comp[i]->stun_sock = NULL;
+            }
+            if (ice_st->comp[i]->turn_sock) {
+                pj_turn_sock_set_user_data(ice_st->comp[i]->turn_sock, NULL);
+                pj_turn_sock_destroy(ice_st->comp[i]->turn_sock);
+                ice_st->comp[i]->turn_sock = NULL;
+            }
         }
     }
     ice_st->comp_cnt = 0;
+
+    /* Destroy reference counter */
+    if (ice_st->busy_cnt) {
+        pj_assert(pj_atomic_get(ice_st->busy_cnt)==0);
+        pj_atomic_destroy(ice_st->busy_cnt);
+        ice_st->busy_cnt = NULL;
+    }
 
     /* Done */
     pj_pool_release(ice_st->pool);
-
-    if (reason == PJ_SUCCESS) {
-        PJ_LOG(4,(obj_name, "ICE stream transport destroyed"));
-    }
+}
+
+/* Notification about failure */
+static void sess_fail(pj_ice_strans *ice_st, pj_ice_strans_op op,
+                      const char *title, pj_status_t status)
+{
+    char errmsg[PJ_ERR_MSG_SIZE];
+
+    pj_strerror(status, errmsg, sizeof(errmsg));
+    PJ_LOG(4,(ice_st->obj_name, "%s: %s", title, errmsg));
+
+    if (op==PJ_ICE_STRANS_OP_INIT && ice_st->cb_called)
+        return;
+
+    ice_st->cb_called = PJ_TRUE;
+
+    if (ice_st->cb.on_ice_complete)
+        (*ice_st->cb.on_ice_complete)(ice_st, op, status);
+}
+
+/* Update initialization status */
+static void sess_init_update(pj_ice_strans *ice_st)
+{
+    unsigned i;
+
+    /* Ignore if init callback has been called */
+    if (ice_st->cb_called)
+        return;
+
+    /* Notify application when all candidates have been gathered */
+    for (i=0; i<ice_st->comp_cnt; ++i) {
+        unsigned j;
+        pj_ice_strans_comp *comp = ice_st->comp[i];
+
+        for (j=0; j<comp->cand_cnt; ++j) {
+            pj_ice_sess_cand *cand = &comp->cand_list[j];
+
+            if (cand->status == PJ_EPENDING)
+                return;
+        }
+    }
+
+    /* All candidates have been gathered */
+    ice_st->cb_called = PJ_TRUE;
+    if (ice_st->cb.on_ice_complete)
+        (*ice_st->cb.on_ice_complete)(ice_st, PJ_ICE_STRANS_OP_INIT, 
+                                      PJ_SUCCESS);
 }
 
@@ -163 +550 @@
 PJ_DEF(pj_status_t) pj_ice_strans_destroy(pj_ice_strans *ice_st)
 {
-    destroy_ice_st(ice_st, PJ_SUCCESS);
+    char obj_name[PJ_MAX_OBJ_NAME];
+
+    PJ_ASSERT_RETURN(ice_st, PJ_EINVAL);
+
+    ice_st->destroy_req = PJ_TRUE;
+    if (pj_atomic_get(ice_st->busy_cnt) > 0) {
+        PJ_LOG(5,(ice_st->obj_name, 
+                  "ICE strans object is busy, will destroy later"));
+        return PJ_EPENDING;
+    }
+    
+    pj_memcpy(obj_name, ice_st->obj_name, PJ_MAX_OBJ_NAME);
+    destroy_ice_st(ice_st);
+
+    PJ_LOG(4,(obj_name, "ICE stream transport destroyed"));
     return PJ_SUCCESS;
 }
 
-/*
- * Resolve STUN server
- */
-PJ_DEF(pj_status_t) pj_ice_strans_set_stun_domain(pj_ice_strans *ice_st,
-                                                  pj_dns_resolver *resolver,
-                                                  const pj_str_t *domain)
-{
-    /* Yeah, TODO */
-    PJ_UNUSED_ARG(ice_st);
-    PJ_UNUSED_ARG(resolver);
-    PJ_UNUSED_ARG(domain);
-    return -1;
-}
-
-/*
- * Set STUN server address.
- */
-PJ_DEF(pj_status_t) pj_ice_strans_set_stun_srv( pj_ice_strans *ice_st,
-                                                const pj_sockaddr_in *stun_srv,
-                                                const pj_sockaddr_in *turn_srv)
-{
-    PJ_ASSERT_RETURN(ice_st, PJ_EINVAL);
-    /* Must not have pending resolver job */
-    PJ_ASSERT_RETURN(ice_st->has_rjob==PJ_FALSE, PJ_EINVALIDOP);
-
-    if (stun_srv) {
-        pj_memcpy(&ice_st->stun_srv, stun_srv, sizeof(pj_sockaddr_in));
+
+/*
+ * Increment busy counter.
+ */
+static void sess_add_ref(pj_ice_strans *ice_st)
+{
+    pj_atomic_inc(ice_st->busy_cnt);
+}
+
+/*
+ * Decrement busy counter. If the counter has reached zero and destroy
+ * has been requested, destroy the object and return FALSE.
+ */
+static pj_bool_t sess_dec_ref(pj_ice_strans *ice_st)
+{
+    int count = pj_atomic_dec_and_get(ice_st->busy_cnt);
+    pj_assert(count >= 0);
+    if (count==0 && ice_st->destroy_req) {
+        pj_ice_strans_destroy(ice_st);
+        return PJ_FALSE;
     } else {
-        pj_bzero(&ice_st->stun_srv, sizeof(pj_sockaddr_in));
-    }
-
-    if (turn_srv) {
-        pj_memcpy(&ice_st->turn_srv, turn_srv, sizeof(pj_sockaddr_in));
-    } else {
-        pj_bzero(&ice_st->turn_srv, sizeof(pj_sockaddr_in));
-    }
-
-    return PJ_SUCCESS;
-}
-
-/* Add new candidate */
-static pj_status_t add_cand( pj_ice_strans *ice_st,
-                             pj_ice_strans_comp *comp,
-                             unsigned comp_id,
-                             pj_ice_cand_type type,
-                             pj_uint16_t local_pref,
-                             const pj_sockaddr_in *addr,
-                             pj_bool_t set_default)
-{
-    pj_ice_strans_cand *cand;
-    unsigned i;
-
-    PJ_ASSERT_RETURN(ice_st && comp && addr, PJ_EINVAL);
-    PJ_ASSERT_RETURN(comp->cand_cnt < PJ_ICE_ST_MAX_CAND, PJ_ETOOMANY);
-
-    /* Check that we don't have candidate with the same
-     * address.
-     */
-    for (i=0; i<comp->cand_cnt; ++i) {
-        if (pj_memcmp(addr, &comp->cand_list[i].addr, 
-                      sizeof(pj_sockaddr_in))==0)
-        {
-            /* Duplicate */
-            PJ_LOG(5,(ice_st->obj_name, "Duplicate candidate not added"));
-            return PJ_SUCCESS;
-        }
-    }
-
-    cand = &comp->cand_list[comp->cand_cnt];
-
-    pj_bzero(cand, sizeof(*cand));
-    cand->type = type;
-    cand->status = PJ_SUCCESS;
-    pj_memcpy(&cand->addr, addr, sizeof(pj_sockaddr_in));
-    cand->ice_cand_id = -1;
-    cand->local_pref = local_pref;
-    pj_ice_calc_foundation(ice_st->pool, &cand->foundation, type, 
-                           &comp->local_addr);
-
-    if (set_default) 
-        comp->default_cand = comp->cand_cnt;
-
-    PJ_LOG(5,(ice_st->obj_name, 
-              "Candidate %s:%d (type=%s) added to component %d",
-              pj_inet_ntoa(addr->sin_addr),
-              (int)pj_ntohs(addr->sin_port), 
-              pj_ice_get_cand_type_name(type),
-              comp_id));
-    
-    comp->cand_cnt++;
-    return PJ_SUCCESS;
-}
-
-/*  Create new component (i.e. socket)  */
-static pj_status_t create_component(pj_ice_strans *ice_st,
-                                    unsigned comp_id,
-                                    pj_uint32_t options,
-                                    const pj_sockaddr_in *addr,
-                                    pj_ice_strans_comp **p_comp)
-{
-    enum { MAX_RETRY=100, PORT_INC=2 };
-    pj_ioqueue_callback ioqueue_cb;
-    pj_ice_strans_comp *comp;
-    int retry, addr_len;
-    struct {
-        pj_uint32_t a1, a2, a3;
-    } tsx_id;
-    pj_status_t status;
-
-    comp = PJ_POOL_ZALLOC_T(ice_st->pool, pj_ice_strans_comp);
-    comp->ice_st = ice_st;
-    comp->comp_id = comp_id;
-    comp->options = options;
-    comp->sock = PJ_INVALID_SOCKET;
-    comp->last_status = PJ_SUCCESS;
-
-    /* Create transaction ID for STUN keep alives */
-    tsx_id.a1 = 0;
-    tsx_id.a2 = comp_id;
-    tsx_id.a3 = (pj_uint32_t) (unsigned long) ice_st;
-    pj_memcpy(comp->ka_tsx_id, &tsx_id, sizeof(comp->ka_tsx_id));
-
-    /* Create socket */
-    status = pj_sock_socket(pj_AF_INET(), pj_SOCK_DGRAM(), 0, &comp->sock);
-    if (status != PJ_SUCCESS)
-        return status;
-
-    /* Init address */
-    if (addr) 
-        pj_memcpy(&comp->local_addr, addr, sizeof(pj_sockaddr_in));
-    else 
-        pj_sockaddr_in_init(&comp->local_addr.ipv4, NULL, 0);
-
-    /* Retry binding socket */
-    for (retry=0; retry<MAX_RETRY; ++retry) {
-        pj_uint16_t port;
-
-        status = pj_sock_bind(comp->sock, &comp->local_addr, 
-                              sizeof(pj_sockaddr_in));
-        if (status == PJ_SUCCESS)
-            break;
-
-        if (options & PJ_ICE_ST_OPT_NO_PORT_RETRY)
-            goto on_error;
-
-        port = pj_ntohs(comp->local_addr.ipv4.sin_port);
-        port += PORT_INC;
-        comp->local_addr.ipv4.sin_port = pj_htons(port);
-    }
-
-    /* Get the actual port where the socket is bound to.
-     * (don't care about the address, it will be retrieved later)
-     */
-    addr_len = sizeof(comp->local_addr);
-    status = pj_sock_getsockname(comp->sock, &comp->local_addr, &addr_len);
-    if (status != PJ_SUCCESS)
-        goto on_error;
-
-    /* Register to ioqueue */
-    pj_bzero(&ioqueue_cb, sizeof(ioqueue_cb));
-    ioqueue_cb.on_read_complete = &on_read_complete;
-    status = pj_ioqueue_register_sock(ice_st->pool, ice_st->stun_cfg.ioqueue, 
-                                      comp->sock, comp, &ioqueue_cb, 
-                                      &comp->key);
-    if (status != PJ_SUCCESS)
-        goto on_error;
-
-    /* Disable concurrency */
-    status = pj_ioqueue_set_concurrency(comp->key, PJ_FALSE);
-    if (status != PJ_SUCCESS)
-        goto on_error;
-
-    pj_ioqueue_op_key_init(&comp->read_op, sizeof(comp->read_op));
-    pj_ioqueue_op_key_init(&comp->write_op, sizeof(comp->write_op));
-
-    /* Kick start reading the socket */
-    on_read_complete(comp->key, &comp->read_op, 0);
-
-    /* If the socket is bound to INADDR_ANY, then lookup all interfaces in
-     * the host and add them into cand_list. Otherwise if the socket is bound
-     * to a specific interface, then only add that specific interface to
-     * cand_list.
-     */
-    if (((options & PJ_ICE_ST_OPT_DONT_ADD_CAND)==0) &&
-        comp->local_addr.ipv4.sin_addr.s_addr == 0) 
-    {
-        /* Socket is bound to INADDR_ANY */
-        unsigned i, ifs_cnt;
-        pj_sockaddr ifs[PJ_ICE_ST_MAX_CAND-2];
-
-        /* Reset default candidate */
-        comp->default_cand = -1;
-
-        /* Enum all IP interfaces in the host */
-        ifs_cnt = PJ_ARRAY_SIZE(ifs);
-        status = pj_enum_ip_interface(pj_AF_INET(), &ifs_cnt, ifs);
-        if (status != PJ_SUCCESS)
-            goto on_error;
-
-        /* Set default IP interface as the base address */
-        status = pj_gethostip(pj_AF_INET(), &comp->local_addr);
-        if (status != PJ_SUCCESS)
-            goto on_error;
-
-        /* Add candidate entry for each interface */
-        for (i=0; i<ifs_cnt; ++i) {
-            pj_sockaddr_in cand_addr;
-            pj_bool_t set_default;
-            pj_uint16_t local_pref;
-
-            /* Ignore 127.0.0.0/24 address */
-            if ((pj_ntohl(ifs[i].ipv4.sin_addr.s_addr) >> 24)==127)
-                continue;
-
-            pj_memcpy(&cand_addr, &comp->local_addr, sizeof(pj_sockaddr_in));
-            cand_addr.sin_addr.s_addr = ifs[i].ipv4.sin_addr.s_addr;
-
-
-            /* If the IP address is equal to local address, assign it
-             * as default candidate.
-             */
-            if (ifs[i].ipv4.sin_addr.s_addr == comp->local_addr.ipv4.sin_addr.s_addr) {
-                set_default = PJ_TRUE;
-                local_pref = 65535;
-            } else {
-                set_default = PJ_FALSE;
-                local_pref = 0;
-            }
-
-            status = add_cand(ice_st, comp, comp_id, 
-                              PJ_ICE_CAND_TYPE_HOST, 
-                              local_pref, &cand_addr, set_default);
-            if (status != PJ_SUCCESS)
-                goto on_error;
-        }
-
-
-    } else if ((options & PJ_ICE_ST_OPT_DONT_ADD_CAND)==0) {
-        /* Socket is bound to specific address. 
-         * In this case only add that address as a single entry in the
-         * cand_list table.
-         */
-        status = add_cand(ice_st, comp, comp_id, 
-                          PJ_ICE_CAND_TYPE_HOST, 
-                          65535, &comp->local_addr.ipv4,
-                          PJ_TRUE);
-        if (status != PJ_SUCCESS)
-            goto on_error;
-
-    } else if (options & PJ_ICE_ST_OPT_DONT_ADD_CAND) {
-        /* If application doesn't want to add candidate, just fix local_addr
-         * in case its value is zero.
-         */
-        if (comp->local_addr.ipv4.sin_addr.s_addr == 0) {
-            status = pj_gethostip(pj_AF_INET(), &comp->local_addr);
-            if (status != PJ_SUCCESS)
-                return status;
-        }
-    }
-
-
-    /* Done */
-    if (p_comp)
-        *p_comp = comp;
-
-    return PJ_SUCCESS;
-
-on_error:
-    destroy_component(comp);
-    return status;
-}
-
-/* 
- * This is callback called by ioqueue on incoming packet 
- */
-static void on_read_complete(pj_ioqueue_key_t *key, 
-                             pj_ioqueue_op_key_t *op_key, 
-                             pj_ssize_t bytes_read)
-{
-    pj_ice_strans_comp *comp = (pj_ice_strans_comp*) 
-                            pj_ioqueue_get_user_data(key);
-    pj_ice_strans *ice_st = comp->ice_st;
-    pj_ssize_t pkt_size;
-    enum { RETRY = 10 };
-    unsigned retry;
-    pj_status_t status;
-
-    if (bytes_read > 0) {
-        /*
-         * Okay, we got a packet from the socket for the component. There is
-         * a bit of situation here, since this packet could be one of these:
-         *
-         * 1) this could be the response of STUN binding request sent by
-         *    this component to a) an initial request to get the STUN mapped
-         *    address of this component, or b) subsequent request to keep
-         *    the binding alive.
-         * 
-         * 2) this could be a packet (STUN or not STUN) sent from the STUN
-         *    relay server. In this case, still there are few options to do
-         *    for this packet: a) process this locally if this packet is
-         *    related to TURN session management (e.g. Allocate response),
-         *    b) forward this packet to ICE if this is related to ICE
-         *    discovery process.
-         *
-         * 3) this could be a STUN request or response sent as part of ICE
-         *    discovery process.
-         *
-         * 4) this could be application's packet, e.g. when ICE processing
-         *    is done and agents start sending RTP/RTCP packets to each
-         *    other, or when ICE processing is not done and this ICE stream
-         *    transport decides to allow sending data.
-         *
-         * So far we don't have good solution for this.
-         * The process below is just a workaround.
-         */
-        status = pj_stun_msg_check(comp->pkt, bytes_read, 
-                                   PJ_STUN_IS_DATAGRAM);
-
-        if (status == PJ_SUCCESS) {
-            if (comp->stun_sess &&
-                PJ_STUN_IS_RESPONSE(((pj_stun_msg_hdr*)comp->pkt)->type) &&
-                pj_memcmp(comp->pkt+8, comp->ka_tsx_id, 12) == 0) 
-            {
-                status = pj_stun_session_on_rx_pkt(comp->stun_sess, comp->pkt,
-                                                   bytes_read, 
-                                                   PJ_STUN_IS_DATAGRAM, NULL,
-                                                   NULL, &comp->src_addr, 
-                                                   comp->src_addr_len);
-            } else if (ice_st->ice) {
-                PJ_TODO(DISTINGUISH_BETWEEN_LOCAL_AND_RELAY);
-
-                TRACE_PKT((comp->ice_st->obj_name, 
-                          "Component %d RX packet from %s:%d",
-                          comp->comp_id,
-                          pj_inet_ntoa(comp->src_addr.ipv4.sin_addr),
-                          (int)pj_ntohs(comp->src_addr.ipv4.sin_port)));
-
-                status = pj_ice_sess_on_rx_pkt(ice_st->ice, comp->comp_id, 
-                                               comp->pkt, bytes_read,
-                                               &comp->src_addr, 
-                                               comp->src_addr_len);
-            } else {
-                /* This must have been a very late STUN reponse,
-                 * or an early STUN Binding Request when our local
-                 * ICE has not been created yet. */
-            }
-        } else {
-            (*ice_st->cb.on_rx_data)(ice_st, comp->comp_id, 
-                                     comp->pkt, bytes_read, 
-                                     &comp->src_addr, comp->src_addr_len);
-        }
-
-    } else if (bytes_read < 0) {
-        ice_st_perror(comp->ice_st, "ioqueue read callback error", 
-                      -bytes_read);
-    }
-
-    /* Read next packet */
-    for (retry=0; retry<RETRY;) {
-        pkt_size = sizeof(comp->pkt);
-        comp->src_addr_len = sizeof(comp->src_addr);
-        status = pj_ioqueue_recvfrom(key, op_key, comp->pkt, &pkt_size, 
-                                     PJ_IOQUEUE_ALWAYS_ASYNC,
-                                     &comp->src_addr, &comp->src_addr_len);
-        if (status == PJ_STATUS_FROM_OS(OSERR_EWOULDBLOCK) ||
-            status == PJ_STATUS_FROM_OS(OSERR_EINPROGRESS) || 
-            status == PJ_STATUS_FROM_OS(OSERR_ECONNRESET))
-        {
-            ice_st_perror(comp->ice_st, "ioqueue recvfrom() error", status);
-            ++retry;
-            continue;
-        } else if (status != PJ_SUCCESS && status != PJ_EPENDING) {
-            retry += 2;
-            ice_st_perror(comp->ice_st, "ioqueue recvfrom() error", status);
-        } else {
-            break;
-        }
-    }
-}
-
-/* 
- * Destroy a component 
- */
-static void destroy_component(pj_ice_strans_comp *comp)
-{
-    if (comp->stun_sess) {
-        pj_stun_session_destroy(comp->stun_sess);
-        comp->stun_sess = NULL;
-    }
-
-    if (comp->key) {
-        pj_ioqueue_unregister(comp->key);
-        comp->key = NULL;
-        comp->sock = PJ_INVALID_SOCKET;
-    } else if (comp->sock != PJ_INVALID_SOCKET && comp->sock != 0) {
-        pj_sock_close(comp->sock);
-        comp->sock = PJ_INVALID_SOCKET;
-    }
-}
-
-
-/* STUN keep-alive timer callback */
-static void ka_timer_cb(pj_timer_heap_t *th, pj_timer_entry *te)
-{
-    pj_ice_strans *ice_st = (pj_ice_strans*)te->user_data;
-    unsigned i;
-    pj_status_t status;
-
-    PJ_UNUSED_ARG(th);
-
-    ice_st->ka_timer.id = PJ_FALSE;
-
-    for (i=0; i<ice_st->comp_cnt; ++i) {
-        pj_ice_strans_comp *comp = ice_st->comp[i];
-        pj_stun_tx_data *tdata;
-        unsigned j;
-
-        /* Does this component have STUN server reflexive candidate? */
-        for (j=0; j<comp->cand_cnt; ++j) {
-            if (comp->cand_list[j].type == PJ_ICE_CAND_TYPE_SRFLX)
-                break;
-        }
-        if (j == comp->cand_cnt)
-            continue;
-
-        /* Create STUN binding request */
-        status = pj_stun_session_create_req(comp->stun_sess,
-                                            PJ_STUN_BINDING_REQUEST, 
-                                            PJ_STUN_MAGIC,
-                                            comp->ka_tsx_id, &tdata);
-        if (status != PJ_SUCCESS)
-            continue;
-
-        /* tdata->user_data is NULL for keep-alive */
-        //tdata->user_data = NULL;
-
-        ++comp->pending_cnt;
-
-
-        /* Send STUN binding request */
-        PJ_LOG(5,(ice_st->obj_name, "Sending STUN keep-alive from %s;%d",
-                  pj_inet_ntoa(comp->local_addr.ipv4.sin_addr),
-                  pj_ntohs(comp->local_addr.ipv4.sin_port)));
-        status = pj_stun_session_send_msg(comp->stun_sess, &comp->cand_list[j],
-                                          PJ_FALSE, PJ_TRUE, &ice_st->stun_srv,
-                                          sizeof(pj_sockaddr_in), tdata);
-        if (status != PJ_SUCCESS) {
-            --comp->pending_cnt;
-        }
-    }
-
-    /* Start next timer */
-    start_ka_timer(ice_st);
-}
-
-/* Start STUN keep-alive timer */
-static void start_ka_timer(pj_ice_strans *ice_st)
-{
-    pj_time_val delay;
-
-    /* Skip if timer is already running */
-    if (ice_st->ka_timer.id != PJ_FALSE)
-        return;
-
-    delay.sec = PJ_ICE_ST_KEEP_ALIVE_MIN;
-    delay.msec = pj_rand() % (PJ_ICE_ST_KEEP_ALIVE_MAX_RAND * 1000);
-    pj_time_val_normalize(&delay);
-
-    ice_st->ka_timer.cb = &ka_timer_cb;
-    ice_st->ka_timer.user_data = ice_st;
-    
-    if (pj_timer_heap_schedule(ice_st->stun_cfg.timer_heap, 
-                               &ice_st->ka_timer, &delay)==PJ_SUCCESS)
-    {
-        ice_st->ka_timer.id = PJ_TRUE;
-    }
-}
-
-
-/* Stop STUN keep-alive timer */
-static void stop_ka_timer(pj_ice_strans *ice_st)
-{
-    /* Skip if timer is already stop */
-    if (ice_st->ka_timer.id == PJ_FALSE)
-        return;
-
-    pj_timer_heap_cancel(ice_st->stun_cfg.timer_heap, &ice_st->ka_timer);
-    ice_st->ka_timer.id = PJ_FALSE;
-}
-
-
-/*
- * Add STUN mapping to a component.
- */
-static pj_status_t get_stun_mapped_addr(pj_ice_strans *ice_st,
-                                        pj_ice_strans_comp *comp)
-{
-    pj_ice_strans_cand *cand;
-    pj_stun_session_cb sess_cb;
-    pj_stun_tx_data *tdata;
-    pj_status_t status;
-
-    PJ_ASSERT_RETURN(ice_st && comp, PJ_EINVAL);
-    
-    /* Bail out if STUN server is still being resolved */
-    if (ice_st->has_rjob)
-        return PJ_EBUSY;
-
-    /* Just return (successfully) if STUN server is not configured */
-    if (ice_st->stun_srv.sin_family == 0)
-        return PJ_SUCCESS;
-
-
-    /* Create STUN session for this component */
-    pj_bzero(&sess_cb, sizeof(sess_cb));
-    sess_cb.on_request_complete = &stun_on_request_complete;
-    sess_cb.on_send_msg = &stun_on_send_msg;
-    status = pj_stun_session_create(&ice_st->stun_cfg, ice_st->obj_name,
-                                    &sess_cb, PJ_FALSE, &comp->stun_sess);
-    if (status != PJ_SUCCESS)
-        return status;
-
-    /* Associate component with STUN session */
-    pj_stun_session_set_user_data(comp->stun_sess, (void*)comp);
-
-    /* Create STUN binding request */
-    status = pj_stun_session_create_req(comp->stun_sess, 
-                                        PJ_STUN_BINDING_REQUEST, 
-                                        PJ_STUN_MAGIC,
-                                        comp->ka_tsx_id, 
-                                        &tdata);
-    if (status != PJ_SUCCESS)
-        return status;
-
-    /* Will be attached to tdata in send_msg() */
-    cand = &comp->cand_list[comp->cand_cnt];
-
-    /* Add pending count first, since stun_on_request_complete()
-     * may be called before this function completes
-     */
-    comp->pending_cnt++;
-
-    /* Add new alias to this component */
-    cand->type = PJ_ICE_CAND_TYPE_SRFLX;
-    cand->status = PJ_EPENDING;
-    cand->ice_cand_id = -1;
-    cand->local_pref = 65535;
-    pj_ice_calc_foundation(ice_st->pool, &cand->foundation, 
-                           PJ_ICE_CAND_TYPE_SRFLX, &comp->local_addr);
-
-    ++comp->cand_cnt;
-
-    /* Send STUN binding request */
-    status = pj_stun_session_send_msg(comp->stun_sess, (void*)cand, PJ_FALSE, 
-                                      PJ_TRUE, &ice_st->stun_srv, 
-                                      sizeof(pj_sockaddr_in), tdata);
-    if (status != PJ_SUCCESS) {
-        --comp->pending_cnt;
-        --comp->cand_cnt;
-        return status;
-    }
-
-    return PJ_SUCCESS;
-}
-
-
-/*
- * Create the component.
- */
-PJ_DEF(pj_status_t) pj_ice_strans_create_comp(pj_ice_strans *ice_st,
-                                              unsigned comp_id,
-                                              pj_uint32_t options,
-                                              const pj_sockaddr_in *addr)
-{
-    pj_ice_strans_comp *comp = NULL;
-    pj_status_t status;
-
-    /* Verify arguments */
-    PJ_ASSERT_RETURN(ice_st && comp_id, PJ_EINVAL);
-
-    /* Check that component ID present */
-    PJ_ASSERT_RETURN(comp_id <= ice_st->comp_cnt, PJNATH_EICEINCOMPID);
-
-    /* Can't add new component while ICE is running */
-    PJ_ASSERT_RETURN(ice_st->ice == NULL, PJ_EBUSY);
-    
-    /* Can't add new component while resolver is running */
-    PJ_ASSERT_RETURN(ice_st->has_rjob == PJ_FALSE, PJ_EBUSY);
-
-
-    /* Create component */
-    status = create_component(ice_st, comp_id, options, addr, &comp);
-    if (status != PJ_SUCCESS)
-        return status;
-
-    if ((options & PJ_ICE_ST_OPT_DISABLE_STUN) == 0) {
-        status = get_stun_mapped_addr(ice_st, comp);
-        if (status != PJ_SUCCESS) {
-            destroy_component(comp);
-            return status;
-        }
-    }
-
-    /* Store this component */
-    ice_st->comp[comp_id-1] = comp;
-
-    return PJ_SUCCESS;
-}
-
-
-PJ_DEF(pj_status_t) pj_ice_strans_add_cand( pj_ice_strans *ice_st,
-                                            unsigned comp_id,
-                                            pj_ice_cand_type type,
-                                            pj_uint16_t local_pref,
-                                            const pj_sockaddr_in *addr,
-                                            pj_bool_t set_default)
-{
-    pj_ice_strans_comp *comp;
-
-
-    PJ_ASSERT_RETURN(ice_st && comp_id && addr, PJ_EINVAL);
-    PJ_ASSERT_RETURN(comp_id <= ice_st->comp_cnt, PJ_EINVAL);
-    PJ_ASSERT_RETURN(ice_st->comp[comp_id-1] != NULL, PJ_EINVALIDOP);
-
-    comp = ice_st->comp[comp_id-1];
-    return add_cand(ice_st, comp, comp_id, type, local_pref, addr, 
-                    set_default);
-}
-
-
-PJ_DEF(pj_status_t) pj_ice_strans_get_comps_status(pj_ice_strans *ice_st)
-{
-    unsigned i;
-    pj_status_t worst = PJ_SUCCESS;
-
-    for (i=0; i<ice_st->comp_cnt; ++i) {
-        pj_ice_strans_comp *comp = ice_st->comp[i];
-
-        if (comp->last_status == PJ_SUCCESS) {
-            /* okay */
-        } else if (comp->pending_cnt && worst==PJ_SUCCESS) {
-            worst = PJ_EPENDING;
-            break;
-        } else if (comp->last_status != PJ_SUCCESS) {
-            worst = comp->last_status;
-            break;
-        }
-
-        if (worst != PJ_SUCCESS)
-            break;
-    }
-
-    return worst;
-}
+        return PJ_TRUE;
+    }
+}
+
+/*
+ * Get user data
+ */
+PJ_DEF(void*) pj_ice_strans_get_user_data(pj_ice_strans *ice_st)
+{
+    PJ_ASSERT_RETURN(ice_st, NULL);
+    return ice_st->user_data;
+}
+
 
 /*
@@ -833 +614 @@
     unsigned i;
     pj_ice_sess_cb ice_cb;
-    const pj_uint8_t srflx_prio[4] = { 100, 126, 110, 0 };
+    //const pj_uint8_t srflx_prio[4] = { 100, 126, 110, 0 };
 
     /* Check arguments */
@@ -849 +630 @@
 
     /* Create! */
-    status = pj_ice_sess_create(&ice_st->stun_cfg, ice_st->obj_name, role,
+    status = pj_ice_sess_create(&ice_st->cfg.stun_cfg, ice_st->obj_name, role,
                                 ice_st->comp_cnt, &ice_cb, 
                                 local_ufrag, local_passwd, &ice_st->ice);
@@ -858 +639 @@
     ice_st->ice->user_data = (void*)ice_st;
 
+#if 0
     /* If default candidate for components are SRFLX one, upload a custom
      * type priority to ICE session so that SRFLX candidates will get
@@ -868 +650 @@
         pj_ice_sess_set_prefs(ice_st->ice, srflx_prio);
     }
-
-
-    /* Add candidates */
+#endif
+
+    /* Add components/candidates */
     for (i=0; i<ice_st->comp_cnt; ++i) {
         unsigned j;
-        pj_ice_strans_comp *comp= ice_st->comp[i];
+        pj_ice_strans_comp *comp = ice_st->comp[i];
+
+        /* Re-enable logging for Send/Data indications */
+        if (comp->turn_sock) {
+            PJ_LOG(5,(ice_st->obj_name, 
+                      "Disabling STUN Indication logging for "
+                      "component %d", i+1));
+            pj_turn_sock_set_log(comp->turn_sock, 0xFFFF);
+        }
 
         for (j=0; j<comp->cand_cnt; ++j) {
-            pj_ice_strans_cand *cand = &comp->cand_list[j];
+            pj_ice_sess_cand *cand = &comp->cand_list[j];
+            unsigned ice_cand_id;
 
             /* Skip if candidate is not ready */
             if (cand->status != PJ_SUCCESS) {
                 PJ_LOG(5,(ice_st->obj_name, 
-                          "Candidate %d in component %d is not added",
+                          "Candidate %d of comp %d is not added (pending)",
                           j, i));
                 continue;
             }
 
+            /* Must have address */
+            pj_assert(pj_sockaddr_has_addr(&cand->addr));
+
+            /* Add the candidate */
             status = pj_ice_sess_add_cand(ice_st->ice, comp->comp_id, 
-                                          cand->type, cand->local_pref, 
+                                          cand->transport_id, cand->type, 
+                                          cand->local_pref, 
                                           &cand->foundation, &cand->addr, 
-                                          &comp->local_addr, NULL, 
-                                          sizeof(pj_sockaddr_in), 
-                                          (unsigned*)&cand->ice_cand_id);
+                                          &cand->base_addr,  &cand->rel_addr,
+                                          pj_sockaddr_get_len(&cand->addr),
+                                          (unsigned*)&ice_cand_id);
             if (status != PJ_SUCCESS)
                 goto on_error;
@@ -908 +704 @@
  */
 PJ_DEF(pj_status_t) pj_ice_strans_enum_cands(pj_ice_strans *ice_st,
-                                         unsigned *count,
-                                         pj_ice_sess_cand cand[])
+                                             unsigned comp_id,
+                                             unsigned *count,
+                                             pj_ice_sess_cand cand[])
 {
     unsigned i, cnt;
-    pj_ice_sess_cand *pcand;
-
-    PJ_ASSERT_RETURN(ice_st && count && cand, PJ_EINVAL);
-    PJ_ASSERT_RETURN(ice_st->ice, PJ_EINVALIDOP);
-
-    cnt = ice_st->ice->lcand_cnt;
+    pj_ice_strans_comp *comp;
+
+    PJ_ASSERT_RETURN(ice_st && comp_id && comp_id <= ice_st->comp_cnt &&
+                     count && cand, PJ_EINVAL);
+
+    comp = ice_st->comp[comp_id - 1];
+    cnt = comp->cand_cnt;
     cnt = (cnt > *count) ? *count : cnt;
-    *count = 0;
 
     for (i=0; i<cnt; ++i) {
-        pcand = &ice_st->ice->lcand[i];
-        pj_memcpy(&cand[i], pcand, sizeof(pj_ice_sess_cand));
+        pj_memcpy(&cand[i], &comp->cand_list[i], sizeof(pj_ice_sess_cand));
     }
 
     *count = cnt;
     return PJ_SUCCESS;
+}
+
+/*
+ * Get default candidate.
+ */
+PJ_DEF(pj_status_t) pj_ice_strans_get_def_cand( pj_ice_strans *ice_st,
+                                                unsigned comp_id,
+                                                pj_ice_sess_cand *cand)
+{
+    const pj_ice_sess_check *valid_pair;
+
+    PJ_ASSERT_RETURN(ice_st && comp_id && comp_id <= ice_st->comp_cnt &&
+                      cand, PJ_EINVAL);
+
+    valid_pair = pj_ice_strans_get_valid_pair(ice_st, comp_id);
+    if (valid_pair) {
+        pj_memcpy(cand, valid_pair->lcand, sizeof(pj_ice_sess_cand));
+    } else {
+        pj_ice_strans_comp *comp = ice_st->comp[comp_id - 1];
+        pj_assert(comp->default_cand>=0 && comp->default_cand<comp->cand_cnt);
+        pj_memcpy(cand, &comp->cand_list[comp->default_cand], 
+                  sizeof(pj_ice_sess_cand));
+    }
+    return PJ_SUCCESS;
+}
+
+/*
+ * Get the current ICE role.
+ */
+PJ_DEF(pj_ice_sess_role) pj_ice_strans_get_role(pj_ice_strans *ice_st)
+{
+    PJ_ASSERT_RETURN(ice_st && ice_st->ice, PJ_ICE_SESS_ROLE_UNKNOWN);
+    return ice_st->ice->role;
+}
+
+/*
+ * Change session role.
+ */
+PJ_DEF(pj_status_t) pj_ice_strans_change_role( pj_ice_strans *ice_st,
+                                               pj_ice_sess_role new_role)
+{
+    PJ_ASSERT_RETURN(ice_st && ice_st->ice, PJ_EINVALIDOP);
+    return pj_ice_sess_change_role(ice_st->ice, new_role);
 }
 
@@ -941 +780 @@
     pj_status_t status;
 
+    PJ_ASSERT_RETURN(ice_st && rem_ufrag && rem_passwd &&
+                     rem_cand_cnt && rem_cand, PJ_EINVAL);
+
+    /* Mark start time */
+    pj_gettimeofday(&ice_st->start_time);
+
+    /* Build check list */
     status = pj_ice_sess_create_check_list(ice_st->ice, rem_ufrag, rem_passwd,
                                            rem_cand_cnt, rem_cand);
@@ -946 +792 @@
         return status;
 
+    /* Start ICE negotiation! */
     status = pj_ice_sess_start_check(ice_st->ice);
     if (status != PJ_SUCCESS) {
@@ -955 +802 @@
 
 /*
+ * Get valid pair.
+ */
+PJ_DEF(const pj_ice_sess_check*) 
+pj_ice_strans_get_valid_pair(const pj_ice_strans *ice_st,
+                             unsigned comp_id)
+{
+    PJ_ASSERT_RETURN(ice_st && comp_id && comp_id <= ice_st->comp_cnt,
+                     NULL);
+    
+    if (ice_st->ice == NULL)
+        return NULL;
+    
+    return ice_st->ice->comp[comp_id-1].valid_check;
+}
+
+/*
  * Stop ICE!
  */
 PJ_DEF(pj_status_t) pj_ice_strans_stop_ice(pj_ice_strans *ice_st)
 {
-    unsigned i;
-
     if (ice_st->ice) {
         pj_ice_sess_destroy(ice_st->ice);
@@ -966 +827 @@
     }
 
-    /* Invalidate all candidate Ids */
-    for (i=0; i<ice_st->comp_cnt; ++i) {
-        unsigned j;
-        for (j=0; j<ice_st->comp[i]->cand_cnt; ++j) {
-            ice_st->comp[i]->cand_list[j].ice_cand_id = -1;
-        }
-    }
-
     return PJ_SUCCESS;
 }
 
 /*
- * Send packet using non-ICE means (e.g. when ICE was not negotiated).
+ * Application wants to send outgoing packet.
  */
 PJ_DEF(pj_status_t) pj_ice_strans_sendto( pj_ice_strans *ice_st,
@@ -998 +851 @@
     /* If ICE is available, send data with ICE */
     if (ice_st->ice) {
-        return pj_ice_sess_send_data(ice_st->ice, comp_id, data, data_len);
-    }
-
-    /* Otherwise send direcly with the socket. This is for compatibility
-     * with remote that doesn't support ICE.
-     */
-    pkt_size = data_len;
-    status = pj_ioqueue_sendto(comp->key, &comp->write_op, 
-                               data, &pkt_size, 0,
-                               dst_addr, dst_addr_len);
-    
-    return (status==PJ_SUCCESS||status==PJ_EPENDING) ? PJ_SUCCESS : status;
+        if (comp->turn_sock) {
+            pj_turn_sock_lock(comp->turn_sock);
+        }
+        status = pj_ice_sess_send_data(ice_st->ice, comp_id, data, data_len);
+        if (comp->turn_sock) {
+            pj_turn_sock_unlock(comp->turn_sock);
+        }
+        return status;
+
+    } else if (comp->stun_sock) {
+
+        pkt_size = data_len;
+        status = pj_stun_sock_sendto(comp->stun_sock, NULL, data, data_len,
+                                     0, dst_addr, dst_addr_len);
+        return (status==PJ_SUCCESS||status==PJ_EPENDING) ? PJ_SUCCESS : status;
+
+    } else
+        return PJ_EINVALIDOP;
 }
 
@@ -1019 +878 @@
 {
     pj_ice_strans *ice_st = (pj_ice_strans*)ice->user_data;
+    pj_time_val t;
+    unsigned msec;
+
+    sess_add_ref(ice_st);
+
+    pj_gettimeofday(&t);
+    PJ_TIME_VAL_SUB(t, ice_st->start_time);
+    msec = PJ_TIME_VAL_MSEC(t);
+
     if (ice_st->cb.on_ice_complete) {
-        (*ice_st->cb.on_ice_complete)(ice_st, status);
-    }
+        if (status != PJ_SUCCESS) {
+            char errmsg[PJ_ERR_MSG_SIZE];
+            pj_strerror(status, errmsg, sizeof(errmsg));
+            PJ_LOG(4,(ice_st->obj_name, 
+                      "ICE negotiation failed after %ds:%03d: %s", 
+                      msec/1000, msec%1000, errmsg));
+        } else {
+            unsigned i;
+            enum {
+                msg_disable_ind = 0xFFFF &
+                                  ~(PJ_STUN_SESS_LOG_TX_IND|
+                                    PJ_STUN_SESS_LOG_RX_IND)
+            };
+
+            PJ_LOG(4,(ice_st->obj_name, 
+                      "ICE negotiation success after %ds:%03d",
+                      msec/1000, msec%1000));
+
+            for (i=0; i<ice_st->comp_cnt; ++i) {
+                const pj_ice_sess_check *check;
+
+                check = pj_ice_strans_get_valid_pair(ice_st, i+1);
+                if (check) {
+                    char lip[PJ_INET6_ADDRSTRLEN+10];
+                    char rip[PJ_INET6_ADDRSTRLEN+10];
+
+                    pj_sockaddr_print(&check->lcand->addr, lip, 
+                                      sizeof(lip), 3);
+                    pj_sockaddr_print(&check->rcand->addr, rip, 
+                                      sizeof(rip), 3);
+
+                    if (check->lcand->transport_id == TP_TURN) {
+                        /* Disable logging for Send/Data indications */
+                        PJ_LOG(5,(ice_st->obj_name, 
+                                  "Disabling STUN Indication logging for "
+                                  "component %d", i+1));
+                        pj_turn_sock_set_log(ice_st->comp[i]->turn_sock,
+                                             msg_disable_ind);
+                    }
+
+                    PJ_LOG(4,(ice_st->obj_name, " Comp %d: "
+                              "sending from %s candidate %s to "
+                              "%s candidate %s",
+                              i+1, 
+                              pj_ice_get_cand_type_name(check->lcand->type),
+                              lip,
+                              pj_ice_get_cand_type_name(check->rcand->type),
+                              rip));
+                              
+                } else {
+                    PJ_LOG(4,(ice_st->obj_name, 
+                              "Comp %d: disabled", i+1));
+                }
+            }
+        }
+
+        (*ice_st->cb.on_ice_complete)(ice_st, PJ_ICE_STRANS_OP_NEGOTIATION, 
+                                      status);
+
+        
+    }
+
+    sess_dec_ref(ice_st);
 }
 
@@ -1029 +958 @@
 static pj_status_t ice_tx_pkt(pj_ice_sess *ice, 
                               unsigned comp_id, 
+                              unsigned transport_id,
                               const void *pkt, pj_size_t size,
                               const pj_sockaddr_t *dst_addr,
@@ -1034 +964 @@
 {
     pj_ice_strans *ice_st = (pj_ice_strans*)ice->user_data;
-    pj_ice_strans_comp *comp = NULL;
-    pj_ssize_t pkt_size;
+    pj_ice_strans_comp *comp;
     pj_status_t status;
 
-    PJ_TODO(TX_TO_RELAY);
-
     PJ_ASSERT_RETURN(comp_id && comp_id <= ice_st->comp_cnt, PJ_EINVAL);
+
     comp = ice_st->comp[comp_id-1];
 
     TRACE_PKT((comp->ice_st->obj_name, 
-              "Component %d TX packet to %s:%d",
-              comp_id,
+              "Component %d TX packet to %s:%d with transport %d",
+              comp_id, 
               pj_inet_ntoa(((pj_sockaddr_in*)dst_addr)->sin_addr),
-              (int)pj_ntohs(((pj_sockaddr_in*)dst_addr)->sin_port)));
-
-    pkt_size = size;
-    status = pj_ioqueue_sendto(comp->key, &comp->write_op, 
-                               pkt, &pkt_size, 0,
-                               dst_addr, dst_addr_len);
+              (int)pj_ntohs(((pj_sockaddr_in*)dst_addr)->sin_port),
+              transport_id));
+
+    if (transport_id == TP_TURN) {
+        if (comp->turn_sock) {
+            status = pj_turn_sock_sendto(comp->turn_sock, 
+                                         (const pj_uint8_t*)pkt, size,
+                                         dst_addr, dst_addr_len);
+        } else {
+            status = PJ_EINVALIDOP;
+        }
+    } else if (transport_id == TP_STUN) {
+        status = pj_stun_sock_sendto(comp->stun_sock, NULL, 
+                                     pkt, size, 0,
+                                     dst_addr, dst_addr_len);
+    } else {
+        pj_assert(!"Invalid transport ID");
+        status = PJ_EINVALIDOP;
+    }
     
     return (status==PJ_SUCCESS||status==PJ_EPENDING) ? PJ_SUCCESS : status;
@@ -1062 +1003 @@
 static void ice_rx_data(pj_ice_sess *ice, 
                         unsigned comp_id, 
+                        unsigned transport_id,
                         void *pkt, pj_size_t size,
                         const pj_sockaddr_t *src_addr,
@@ -1068 +1010 @@
     pj_ice_strans *ice_st = (pj_ice_strans*)ice->user_data;
 
+    PJ_UNUSED_ARG(transport_id);
+
     if (ice_st->cb.on_rx_data) {
         (*ice_st->cb.on_rx_data)(ice_st, comp_id, pkt, size, 
@@ -1074 +1018 @@
 }
 
-/*
- * Callback called by STUN session to send outgoing packet.
- */
-static pj_status_t stun_on_send_msg(pj_stun_session *sess,
-                                    void *token,
-                                    const void *pkt,
-                                    pj_size_t size,
-                                    const pj_sockaddr_t *dst_addr,
-                                    unsigned dst_addr_len)
+/* Notification when incoming packet has been received from
+ * the STUN socket. 
+ */
+static pj_bool_t stun_on_rx_data(pj_stun_sock *stun_sock,
+                                 void *pkt,
+                                 unsigned pkt_len,
+                                 const pj_sockaddr_t *src_addr,
+                                 unsigned addr_len)
 {
     pj_ice_strans_comp *comp;
-    pj_ssize_t pkt_size;
+    pj_ice_strans *ice_st;
     pj_status_t status;
 
-    PJ_UNUSED_ARG(token);
-
-    comp = (pj_ice_strans_comp*) pj_stun_session_get_user_data(sess);
-    pkt_size = size;
-    status = pj_ioqueue_sendto(comp->key, &comp->write_op, 
-                               pkt, &pkt_size, 0,
-                               dst_addr, dst_addr_len);
-    
-    return (status==PJ_SUCCESS||status==PJ_EPENDING) ? PJ_SUCCESS : status;
-}
-
-/*
- * Callback sent by STUN session when outgoing STUN request has
- * completed.
- */
-static void stun_on_request_complete(pj_stun_session *sess,
-                                     pj_status_t status,
-                                     void *token,
-                                     pj_stun_tx_data *tdata,
-                                     const pj_stun_msg *response,
-                                     const pj_sockaddr_t *src_addr,
-                                     unsigned src_addr_len)
+    comp = (pj_ice_strans_comp*) pj_stun_sock_get_user_data(stun_sock);
+    ice_st = comp->ice_st;
+
+    sess_add_ref(ice_st);
+
+    if (ice_st->ice == NULL) {
+        /* The ICE session is gone, but we're still receiving packets.
+         * This could also happen if remote doesn't do ICE. So just
+         * report this to application.
+         */
+        if (ice_st->cb.on_rx_data) {
+            (*ice_st->cb.on_rx_data)(ice_st, comp->comp_id, pkt, pkt_len, 
+                                     src_addr, addr_len);
+        }
+
+    } else {
+
+        /* Hand over the packet to ICE session */
+        status = pj_ice_sess_on_rx_pkt(comp->ice_st->ice, comp->comp_id, 
+                                       TP_STUN, pkt, pkt_len,
+                                       src_addr, addr_len);
+
+        if (status != PJ_SUCCESS) {
+            ice_st_perror(comp->ice_st, "Error processing packet", 
+                          status);
+        }
+    }
+
+    return sess_dec_ref(ice_st);
+}
+
+/* Notifification when asynchronous send operation to the STUN socket
+ * has completed. 
+ */
+static pj_bool_t stun_on_data_sent(pj_stun_sock *stun_sock,
+                                   pj_ioqueue_op_key_t *send_key,
+                                   pj_ssize_t sent)
+{
+    PJ_UNUSED_ARG(stun_sock);
+    PJ_UNUSED_ARG(send_key);
+    PJ_UNUSED_ARG(sent);
+    return PJ_TRUE;
+}
+
+/* Notification when the status of the STUN transport has changed. */
+static pj_bool_t stun_on_status(pj_stun_sock *stun_sock, 
+                                pj_stun_sock_op op,
+                                pj_status_t status)
 {
     pj_ice_strans_comp *comp;
-    pj_ice_strans_cand *cand = NULL;
-    pj_stun_xor_mapped_addr_attr *xa;
-    pj_stun_mapped_addr_attr *ma;
-    pj_sockaddr *mapped_addr;
-    char ip[20];
-
-    comp = (pj_ice_strans_comp*) pj_stun_session_get_user_data(sess);
-    cand = (pj_ice_strans_cand*) token;
-
-    PJ_UNUSED_ARG(token);
-    PJ_UNUSED_ARG(tdata);
-    PJ_UNUSED_ARG(src_addr);
-    PJ_UNUSED_ARG(src_addr_len);
-
-    if (cand == NULL) {
-        /* This is keep-alive */
+    pj_ice_strans *ice_st;
+    pj_ice_sess_cand *cand = NULL;
+    unsigned i;
+
+    comp = (pj_ice_strans_comp*) pj_stun_sock_get_user_data(stun_sock);
+    ice_st = comp->ice_st;
+
+    sess_add_ref(ice_st);
+
+    /* Find the srflx cancidate */
+    for (i=0; i<comp->cand_cnt; ++i) {
+        if (comp->cand_list[i].type == PJ_ICE_CAND_TYPE_SRFLX) {
+            cand = &comp->cand_list[i];
+            break;
+        }
+    }
+
+    pj_assert(status != PJ_EPENDING);
+
+    switch (op) {
+    case PJ_STUN_SOCK_DNS_OP:
         if (status != PJ_SUCCESS) {
-            ice_st_perror(comp->ice_st, "STUN keep-alive request failed",
+            /* May not have cand, e.g. when error during init */
+            if (cand)
+                cand->status = status;
+            sess_fail(ice_st, PJ_ICE_STRANS_OP_INIT, "DNS resolution failed", 
+                      status);
+        }
+        break;
+    case PJ_STUN_SOCK_BINDING_OP:
+        if (status == PJ_SUCCESS) {
+            pj_stun_sock_info info;
+
+            status = pj_stun_sock_get_info(stun_sock, &info);
+            if (status == PJ_SUCCESS) {
+                char ipaddr[PJ_INET6_ADDRSTRLEN+10];
+                pj_bool_t dup = PJ_FALSE;
+
+                /* Eliminate the srflx candidate if the address is
+                 * equal to other (host) candidates.
+                 */
+                for (i=0; i<comp->cand_cnt; ++i) {
+                    if (comp->cand_list[i].type == PJ_ICE_CAND_TYPE_HOST &&
+                        pj_sockaddr_cmp(&comp->cand_list[i].addr,
+                                        &info.mapped_addr) == 0)
+                    {
+                        dup = PJ_TRUE;
+                        break;
+                    }
+                }
+
+                if (dup) {
+                    /* Duplicate found, remove the srflx candidate */
+                    pj_array_erase(comp->cand_list, sizeof(comp->cand_list[0]),
+                                   comp->cand_cnt, cand - comp->cand_list);
+                    --comp->cand_cnt;
+                } else {
+                    /* Otherwise update the address */
+                    pj_sockaddr_cp(&cand->addr, &info.mapped_addr);
+                    cand->status = PJ_SUCCESS;
+                }
+
+                PJ_LOG(4,(comp->ice_st->obj_name, 
+                          "Comp %d: Binding discovery complete, "
+                          "srflx address is %s",
+                          comp->comp_id, 
+                          pj_sockaddr_print(&info.mapped_addr, ipaddr, 
+                                             sizeof(ipaddr), 3)));
+
+                sess_init_update(ice_st);
+            }
+        }
+
+        if (status != PJ_SUCCESS) {
+            /* May not have cand, e.g. when error during init */
+            if (cand)
+                cand->status = status;
+            sess_fail(ice_st, PJ_ICE_STRANS_OP_INIT, 
+                      "STUN binding request failed", status);
+        }
+        break;
+    case PJ_STUN_SOCK_KEEP_ALIVE_OP:
+        if (status != PJ_SUCCESS) {
+            pj_assert(cand != NULL);
+            cand->status = status;
+            sess_fail(ice_st, PJ_ICE_STRANS_OP_INIT, 
+                      "STUN keep-alive failed", status);
+        }
+        break;
+    }
+
+    return sess_dec_ref(ice_st);
+}
+
+/* Callback when TURN socket has received a packet */
+static void turn_on_rx_data(pj_turn_sock *turn_sock,
+                            void *pkt,
+                            unsigned pkt_len,
+                            const pj_sockaddr_t *peer_addr,
+                            unsigned addr_len)
+{
+    pj_ice_strans_comp *comp;
+    pj_status_t status;
+
+    comp = (pj_ice_strans_comp*) pj_turn_sock_get_user_data(turn_sock);
+    if (comp == NULL) {
+        /* We have disassociated ourselves from the TURN socket */
+        return;
+    }
+
+    sess_add_ref(comp->ice_st);
+
+    if (comp->ice_st->ice == NULL) {
+        /* The ICE session is gone, but we're still receiving packets.
+         * This could also happen if remote doesn't do ICE and application
+         * specifies TURN as the default address in SDP.
+         * So in this case just give the packet to application.
+         */
+        if (comp->ice_st->cb.on_rx_data) {
+            (*comp->ice_st->cb.on_rx_data)(comp->ice_st, comp->comp_id, pkt,
+                                           pkt_len, peer_addr, addr_len);
+        }
+
+    } else {
+
+        /* Hand over the packet to ICE */
+        status = pj_ice_sess_on_rx_pkt(comp->ice_st->ice, comp->comp_id,
+                                       TP_TURN, pkt, pkt_len,
+                                       peer_addr, addr_len);
+
+        if (status != PJ_SUCCESS) {
+            ice_st_perror(comp->ice_st, 
+                          "Error processing packet from TURN relay", 
                           status);
         }
+    }
+
+    sess_dec_ref(comp->ice_st);
+}
+
+
+/* Callback when TURN client state has changed */
+static void turn_on_state(pj_turn_sock *turn_sock, pj_turn_state_t old_state,
+                          pj_turn_state_t new_state)
+{
+    pj_ice_strans_comp *comp;
+
+    comp = (pj_ice_strans_comp*) pj_turn_sock_get_user_data(turn_sock);
+    if (comp == NULL) {
+        /* Not interested in further state notification once the relay is
+         * disconnecting.
+         */
         return;
     }
 
-    /* Decrement pending count for this component */
-    pj_assert(comp->pending_cnt > 0);
-    comp->pending_cnt--;
-
-    if (status == PJNATH_ESTUNTIMEDOUT) {
+    PJ_LOG(5,(comp->ice_st->obj_name, "TURN client state changed %s --> %s",
+              pj_turn_state_name(old_state), pj_turn_state_name(new_state)));
+
+    sess_add_ref(comp->ice_st);
+
+    if (new_state == PJ_TURN_STATE_READY) {
+        pj_turn_session_info rel_info;
+        char ipaddr[PJ_INET6_ADDRSTRLEN+8];
+        pj_ice_sess_cand *cand = NULL;
+        unsigned i;
+
+        /* Get allocation info */
+        pj_turn_sock_get_info(turn_sock, &rel_info);
+
+        /* Find relayed candidate in the component */
+        for (i=0; i<comp->cand_cnt; ++i) {
+            if (comp->cand_list[i].type == PJ_ICE_CAND_TYPE_RELAYED) {
+                cand = &comp->cand_list[i];
+                break;
+            }
+        }
+        pj_assert(cand != NULL);
+
+        /* Update candidate */
+        pj_sockaddr_cp(&cand->addr, &rel_info.relay_addr);
+        pj_sockaddr_cp(&cand->base_addr, &rel_info.relay_addr);
+        pj_sockaddr_cp(&cand->rel_addr, &rel_info.mapped_addr);
+        pj_ice_calc_foundation(comp->ice_st->pool, &cand->foundation, 
+                               PJ_ICE_CAND_TYPE_RELAYED, 
+                               &rel_info.relay_addr);
+        cand->status = PJ_SUCCESS;
 
         PJ_LOG(4,(comp->ice_st->obj_name, 
-                  "STUN Binding request has timed-out, will retry "
-                  "again alter"));
-
-        /* Restart keep-alive timer */
-        start_ka_timer(comp->ice_st);
-        return;
-
-    } else if (status != PJ_SUCCESS) {
-        comp->last_status = cand->status = status;
-        ice_st_perror(comp->ice_st, "STUN Binding request failed", 
-                      cand->status);
-        return;
-    }
-
-    xa = (pj_stun_xor_mapped_addr_attr*)
-         pj_stun_msg_find_attr(response, PJ_STUN_ATTR_XOR_MAPPED_ADDR, 0);
-    ma = (pj_stun_mapped_addr_attr*)
-         pj_stun_msg_find_attr(response, PJ_STUN_ATTR_MAPPED_ADDR, 0);
-
-    if (xa)
-        mapped_addr = &xa->sockaddr;
-    else if (ma)
-        mapped_addr = &ma->sockaddr;
-    else {
-        cand->status = PJNATH_ESTUNNOMAPPEDADDR;
-        ice_st_perror(comp->ice_st, "STUN Binding request failed", 
-                      cand->status);
-        return;
-    }
-
-    /* Save IP address for logging */
-    pj_ansi_strcpy(ip, pj_inet_ntoa(comp->local_addr.ipv4.sin_addr));
-
-    /* Ignore response if it reports the same address */
-    if (comp->local_addr.ipv4.sin_addr.s_addr == mapped_addr->ipv4.sin_addr.s_addr &&
-        comp->local_addr.ipv4.sin_port == mapped_addr->ipv4.sin_port)
-    {
-        PJ_LOG(4,(comp->ice_st->obj_name, 
-                  "Candidate %s:%d is directly connected to Internet, "
-                  "STUN mapped address is ignored",
-                  ip, pj_ntohs(comp->local_addr.ipv4.sin_port)));
-        return;
-    }
-
-    PJ_LOG(5,(comp->ice_st->obj_name, 
-              "STUN mapped address for %s:%d is %s:%d",
-              ip, (int)pj_ntohs(comp->local_addr.ipv4.sin_port),
-              pj_inet_ntoa(mapped_addr->ipv4.sin_addr),
-              (int)pj_ntohs(mapped_addr->ipv4.sin_port)));
-    pj_memcpy(&cand->addr, mapped_addr, sizeof(pj_sockaddr_in));
-    cand->status = PJ_SUCCESS;
-
-    /* Set this candidate as the default candidate */
-    comp->default_cand = (cand - comp->cand_list);
-    comp->last_status = PJ_SUCCESS;
-
-    /* We have STUN, so we must start the keep-alive timer */
-    start_ka_timer(comp->ice_st);
-
-    /* Notify app that STUN address has changed. */
-    if (comp->ice_st->cb.on_addr_change)
-        (*comp->ice_st->cb.on_addr_change)(comp->ice_st, comp->comp_id, 
-                                           (cand - comp->cand_list));
-}
-
+                  "Comp %d: TURN allocation complete, relay address is %s",
+                  comp->comp_id, 
+                  pj_sockaddr_print(&rel_info.relay_addr, ipaddr, 
+                                     sizeof(ipaddr), 3)));
+
+        sess_init_update(comp->ice_st);
+
+    } else if (new_state >= PJ_TURN_STATE_DEALLOCATING) {
+        pj_turn_session_info info;
+
+        pj_turn_sock_get_info(turn_sock, &info);
+
+        /* Unregister ourself from the TURN relay */
+        pj_turn_sock_set_user_data(turn_sock, NULL);
+        comp->turn_sock = NULL;
+
+        /* Set session to fail if we're still initializing */
+        if (old_state < PJ_TURN_STATE_READY) {
+            sess_fail(comp->ice_st, PJ_ICE_STRANS_OP_INIT,
+                      "TURN relay failed", info.last_status);
+        }
+    }
+
+    sess_dec_ref(comp->ice_st);
+}
+