res_pjsip_refer: Fix occasional unexpected BYE sent after receiving a REFER.

A race condition happened between initiating a transfer and requesting
that a dialog termination be delayed.  Occasionally, the transferrer
channels would exit the bridge and hangup before the dialog termination
delay was requested.

* Made request dialog termination delay before initiating the transfer
action.  If the transfer fails then cancel the delayed dialog termination
request.

ASTERISK-24755 #close
Reported by: John Bigelow

Review: https://reviewboard.asterisk.org/r/4460/
........

Merged revisions 432668 from http://svn.asterisk.org/svn/asterisk/branches/13

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@432669 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/include/asterisk/res_pjsip_session.h b/include/asterisk/res_pjsip_session.h
index 8efecb6..728b2c3 100644 (file)
--- a/include/asterisk/res_pjsip_session.h
+++ b/include/asterisk/res_pjsip_session.h
@@ -141,6 +141,8 @@ struct ast_sip_session {
        struct ast_dsp *dsp;
        /*! Whether the termination of the session should be deferred */
        unsigned int defer_terminate:1;
+       /*! Termination requested while termination deferred */
+       unsigned int terminate_while_deferred:1;
        /*! Deferred incoming re-invite */
        pjsip_rx_data *deferred_reinvite;
        /*! Current T.38 state */
@@ -449,8 +451,18 @@ void ast_sip_session_terminate(struct ast_sip_session *session, int response);
  * \brief Defer local termination of a session until remote side terminates, or an amount of time passes
  *
  * \param session The session to defer termination on
+ *
+ * \retval 0 Success
+ * \retval -1 Failure
+ */
+int ast_sip_session_defer_termination(struct ast_sip_session *session);
+
+/*!
+ * \brief Cancel a pending deferred termination.
+ *
+ * \param session The session to cancel a deferred termination on.
  */
-void ast_sip_session_defer_termination(struct ast_sip_session *session);
+void ast_sip_session_defer_termination_cancel(struct ast_sip_session *session);
 
 /*!
  * \brief Register an SDP handler

diff --git a/res/res_pjsip_refer.c b/res/res_pjsip_refer.c
index c1b76ae..5195177 100644 (file)
--- a/res/res_pjsip_refer.c
+++ b/res/res_pjsip_refer.c
@@ -452,20 +452,30 @@ static struct refer_attended *refer_attended_alloc(struct ast_sip_session *trans
        return attended;
 }
 
-/*! \brief Task for attended transfer */
-static int refer_attended(void *data)
+static int defer_termination_cancel(void *data)
 {
-       RAII_VAR(struct refer_attended *, attended, data, ao2_cleanup);
-       int response = 0;
+       struct ast_sip_session *session = data;
 
-       if (!attended->transferer_second->channel) {
-               return -1;
-       }
+       ast_sip_session_defer_termination_cancel(session);
+       ao2_ref(session, -1);
+       return 0;
+}
 
-       ast_debug(3, "Performing a REFER attended transfer - Transferer #1: %s Transferer #2: %s\n",
-               ast_channel_name(attended->transferer_chan), ast_channel_name(attended->transferer_second->channel));
+/*!
+ * \internal
+ * \brief Convert transfer enum to SIP response code.
+ * \since 13.3.0
+ *
+ * \param xfer_code Core transfer function enum result.
+ *
+ * \return SIP response code
+ */
+static int xfer_response_code2sip(enum ast_transfer_result xfer_code)
+{
+       int response;
 
-       switch (ast_bridge_transfer_attended(attended->transferer_chan, attended->transferer_second->channel)) {
+       response = 503;
+       switch (xfer_code) {
        case AST_BRIDGE_TRANSFER_INVALID:
                response = 400;
                break;
@@ -477,21 +487,55 @@ static int refer_attended(void *data)
                break;
        case AST_BRIDGE_TRANSFER_SUCCESS:
                response = 200;
-               ast_sip_session_defer_termination(attended->transferer);
                break;
        }
+       return response;
+}
+
+/*! \brief Task for attended transfer executed by attended->transferer_second serializer */
+static int refer_attended_task(void *data)
+{
+       struct refer_attended *attended = data;
+       int response;
+
+       if (attended->transferer_second->channel) {
+               ast_debug(3, "Performing a REFER attended transfer - Transferer #1: %s Transferer #2: %s\n",
+                       ast_channel_name(attended->transferer_chan),
+                       ast_channel_name(attended->transferer_second->channel));
 
-       ast_debug(3, "Final response for REFER attended transfer - Transferer #1: %s Transferer #2: %s is '%d'\n",
-               ast_channel_name(attended->transferer_chan), ast_channel_name(attended->transferer_second->channel), response);
+               response = xfer_response_code2sip(ast_bridge_transfer_attended(
+                       attended->transferer_chan,
+                       attended->transferer_second->channel));
+
+               ast_debug(3, "Final response for REFER attended transfer - Transferer #1: %s Transferer #2: %s is '%d'\n",
+                       ast_channel_name(attended->transferer_chan),
+                       ast_channel_name(attended->transferer_second->channel),
+                       response);
+       } else {
+               ast_debug(3, "Received REFER request on channel '%s' but other channel has gone.\n",
+                       ast_channel_name(attended->transferer_chan));
+               response = 603;
+       }
 
-       if (attended->progress && response) {
-               struct refer_progress_notification *notification = refer_progress_notification_alloc(attended->progress, response, PJSIP_EVSUB_STATE_TERMINATED);
+       if (attended->progress) {
+               struct refer_progress_notification *notification;
 
+               notification = refer_progress_notification_alloc(attended->progress, response,
+                       PJSIP_EVSUB_STATE_TERMINATED);
                if (notification) {
                        refer_progress_notify(notification);
                }
        }
 
+       if (response != 200) {
+               if (!ast_sip_push_task(attended->transferer->serializer,
+                       defer_termination_cancel, attended->transferer)) {
+                       /* Gave the ref to the pushed task. */
+                       attended->transferer = NULL;
+               }
+       }
+
+       ao2_ref(attended, -1);
        return 0;
 }
 
@@ -687,8 +731,16 @@ static int refer_incoming_attended_request(struct ast_sip_session *session, pjsi
                        return 500;
                }
 
+               if (ast_sip_session_defer_termination(session)) {
+                       ast_log(LOG_ERROR, "Received REFER request on channel '%s' from endpoint '%s' for local dialog but could not defer termination, rejecting\n",
+                               ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
+                       ao2_cleanup(attended);
+                       return 500;
+               }
+
                /* Push it to the other session, which will have both channels with minimal locking */
-               if (ast_sip_push_task(other_session->serializer, refer_attended, attended)) {
+               if (ast_sip_push_task(other_session->serializer, refer_attended_task, attended)) {
+                       ast_sip_session_defer_termination_cancel(session);
                        ao2_cleanup(attended);
                        return 500;
                }
@@ -700,6 +752,7 @@ static int refer_incoming_attended_request(struct ast_sip_session *session, pjsi
        } else {
                const char *context;
                struct refer_blind refer = { 0, };
+               int response;
 
                DETERMINE_TRANSFER_CONTEXT(context, session);
 
@@ -715,19 +768,19 @@ static int refer_incoming_attended_request(struct ast_sip_session *session, pjsi
                refer.replaces = replaces;
                refer.refer_to = target_uri;
 
-               switch (ast_bridge_transfer_blind(1, session->channel, "external_replaces", context, refer_blind_callback, &refer)) {
-               case AST_BRIDGE_TRANSFER_INVALID:
-                       return 400;
-               case AST_BRIDGE_TRANSFER_NOT_PERMITTED:
-                       return 403;
-               case AST_BRIDGE_TRANSFER_FAIL:
+               if (ast_sip_session_defer_termination(session)) {
+                       ast_log(LOG_ERROR, "Received REFER for remote session on channel '%s' from endpoint '%s' but could not defer termination, rejecting\n",
+                               ast_channel_name(session->channel),
+                               ast_sorcery_object_get_id(session->endpoint));
                        return 500;
-               case AST_BRIDGE_TRANSFER_SUCCESS:
-                       ast_sip_session_defer_termination(session);
-                       return 200;
                }
 
-               return 503;
+               response = xfer_response_code2sip(ast_bridge_transfer_blind(1, session->channel,
+                       "external_replaces", context, refer_blind_callback, &refer));
+               if (response != 200) {
+                       ast_sip_session_defer_termination_cancel(session);
+               }
+               return response;
        }
 }
 
@@ -737,6 +790,7 @@ static int refer_incoming_blind_request(struct ast_sip_session *session, pjsip_r
        const char *context;
        char exten[AST_MAX_EXTENSION];
        struct refer_blind refer = { 0, };
+       int response;
 
        /* If no explicit transfer context has been provided use their configured context */
        DETERMINE_TRANSFER_CONTEXT(context, session);
@@ -754,19 +808,19 @@ static int refer_incoming_blind_request(struct ast_sip_session *session, pjsip_r
        refer.rdata = rdata;
        refer.refer_to = target;
 
-       switch (ast_bridge_transfer_blind(1, session->channel, exten, context, refer_blind_callback, &refer)) {
-       case AST_BRIDGE_TRANSFER_INVALID:
-               return 400;
-       case AST_BRIDGE_TRANSFER_NOT_PERMITTED:
-               return 403;
-       case AST_BRIDGE_TRANSFER_FAIL:
+       if (ast_sip_session_defer_termination(session)) {
+               ast_log(LOG_ERROR, "Channel '%s' from endpoint '%s' attempted blind transfer but could not defer termination, rejecting\n",
+                       ast_channel_name(session->channel),
+                       ast_sorcery_object_get_id(session->endpoint));
                return 500;
-       case AST_BRIDGE_TRANSFER_SUCCESS:
-               ast_sip_session_defer_termination(session);
-               return 200;
        }
 
-       return 503;
+       response = xfer_response_code2sip(ast_bridge_transfer_blind(1, session->channel,
+               exten, context, refer_blind_callback, &refer));
+       if (response != 200) {
+               ast_sip_session_defer_termination_cancel(session);
+       }
+       return response;
 }
 
 /*! \brief Structure used to retrieve channel from another session */

diff --git a/res/res_pjsip_session.c b/res/res_pjsip_session.c
index 9c01d3c..5b75f3c 100644 (file)
--- a/res/res_pjsip_session.c
+++ b/res/res_pjsip_session.c
@@ -1524,6 +1524,7 @@ void ast_sip_session_terminate(struct ast_sip_session *session, int response)
        pjsip_tx_data *packet = NULL;
 
        if (session->defer_terminate) {
+               session->terminate_while_deferred = 1;
                return;
        }
 
@@ -1559,17 +1560,16 @@ void ast_sip_session_terminate(struct ast_sip_session *session, int response)
 
 static int session_termination_task(void *data)
 {
-       RAII_VAR(struct ast_sip_session *, session, data, ao2_cleanup);
-       pjsip_tx_data *packet = NULL;
-
-       if (!session->inv_session) {
-               return 0;
-       }
+       struct ast_sip_session *session = data;
 
-       if (pjsip_inv_end_session(session->inv_session, 603, NULL, &packet) == PJ_SUCCESS) {
-               ast_sip_session_send_request(session, packet);
+       if (session->defer_terminate) {
+               session->defer_terminate = 0;
+               if (session->inv_session) {
+                       ast_sip_session_terminate(session, 0);
+               }
        }
 
+       ao2_ref(session, -1);
        return 0;
 }
 
@@ -1582,9 +1582,13 @@ static void session_termination_cb(pj_timer_heap_t *timer_heap, struct pj_timer_
        }
 }
 
-void ast_sip_session_defer_termination(struct ast_sip_session *session)
+int ast_sip_session_defer_termination(struct ast_sip_session *session)
 {
        pj_time_val delay = { .sec = 60, };
+       int res;
+
+       /* The session should not have an active deferred termination request. */
+       ast_assert(!session->defer_terminate);
 
        session->defer_terminate = 1;
 
@@ -1593,7 +1597,31 @@ void ast_sip_session_defer_termination(struct ast_sip_session *session)
        session->scheduled_termination.user_data = session;
        session->scheduled_termination.cb = session_termination_cb;
 
-       if (pjsip_endpt_schedule_timer(ast_sip_get_pjsip_endpoint(), &session->scheduled_termination, &delay) != PJ_SUCCESS) {
+       res = (pjsip_endpt_schedule_timer(ast_sip_get_pjsip_endpoint(),
+               &session->scheduled_termination, &delay) != PJ_SUCCESS) ? -1 : 0;
+       if (res) {
+               session->defer_terminate = 0;
+               ao2_ref(session, -1);
+       }
+       return res;
+}
+
+void ast_sip_session_defer_termination_cancel(struct ast_sip_session *session)
+{
+       if (!session->defer_terminate) {
+               /* Already canceled or timer fired. */
+               return;
+       }
+       session->defer_terminate = 0;
+
+       if (session->terminate_while_deferred) {
+               /* Complete the termination started by the upper layer. */
+               ast_sip_session_terminate(session, 0);
+       }
+
+       /* Stop the termination timer if it is still running. */
+       if (pj_timer_heap_cancel(pjsip_endpt_get_timer_heap(ast_sip_get_pjsip_endpoint()),
+               &session->scheduled_termination)) {
                ao2_ref(session, -1);
        }
 }

diff --git a/res/res_pjsip_session.exports.in b/res/res_pjsip_session.exports.in
index 5a21b1d..a39485e 100644 (file)
--- a/res/res_pjsip_session.exports.in
+++ b/res/res_pjsip_session.exports.in
@@ -2,6 +2,7 @@
        global:
                LINKER_SYMBOL_PREFIXast_sip_session_terminate;
                LINKER_SYMBOL_PREFIXast_sip_session_defer_termination;
+               LINKER_SYMBOL_PREFIXast_sip_session_defer_termination_cancel;
                LINKER_SYMBOL_PREFIXast_sip_session_register_sdp_handler;
                LINKER_SYMBOL_PREFIXast_sip_session_unregister_sdp_handler;
                LINKER_SYMBOL_PREFIXast_sip_session_register_supplement;