chan_pjsip: Transmit REFER waits for the REFER result setting TRANSFERSTATUS

Previously, when a Transfer (REFER) was performed, chan_pjsip would set
the TRANSFERSTATUS to SUCCESS when the REFER was queued up.  This did not
reflect a successful/unsuccessful transfer the way chan_sip did.
Added a callback module to process the refer subscription information.

Now depends on res_pjsip_pubsub so call transfer progress can be monitored
and reported

ASTERISK-26968 #close
Reported-by: Dan Cropp
Change-Id: If6c27c757c66f71e8b75e3fe49da53ebe62395dc

diff --git a/channels/chan_pjsip.c b/channels/chan_pjsip.c
index d1f7b6a36ff4b95014a23b191cdfabd0bd7813da..8ab1549dd8a09d9647e357fa439dceeeb2e730fe 100644 (file)
--- a/channels/chan_pjsip.c
+++ b/channels/chan_pjsip.c
@@ -28,6 +28,7 @@
 /*** MODULEINFO
        <depend>pjproject</depend>
        <depend>res_pjsip</depend>
+       <depend>res_pjsip_pubsub</depend>
        <depend>res_pjsip_session</depend>
        <support_level>core</support_level>
  ***/
@@ -1894,6 +1895,130 @@ static void transfer_redirect(struct ast_sip_session *session, const char *targe
        ast_queue_control_data(session->channel, AST_CONTROL_TRANSFER, &message, sizeof(message));
 }
 
+/*! \brief REFER Callback module, used to attach session data structure to subscription */
+static pjsip_module refer_callback_module = {
+       .name = { "REFER Callback", 14 },
+       .id = -1,
+};
+
+/*!
+ * \brief Callback function to report status of implicit REFER-NOTIFY subscription.
+ *
+ * This function will be called on any state change in the REFER-NOTIFY subscription.
+ * Its primary purpose is to report SUCCESS/FAILURE of a transfer initiated via
+ * \ref transfer_refer as well as to terminate the subscription, if necessary.
+ */
+static void xfer_client_on_evsub_state(pjsip_evsub *sub, pjsip_event *event)
+{
+       struct ast_sip_session *session;
+       struct ast_channel *chan = NULL;
+       enum ast_control_transfer message = AST_TRANSFER_SUCCESS;
+       int res = 0;
+
+       if (!event) {
+               return;
+       }
+
+       session = pjsip_evsub_get_mod_data(sub, refer_callback_module.id);
+       if (!session) {
+               return;
+       }
+
+       chan = session->channel;
+       if (!chan) {
+               return;
+       }
+
+       if (pjsip_evsub_get_state(sub) == PJSIP_EVSUB_STATE_ACCEPTED) {
+               /* Check if subscription is suppressed and terminate and send completion code, if so. */
+               pjsip_rx_data *rdata;
+               pjsip_generic_string_hdr *refer_sub;
+               const pj_str_t REFER_SUB = { "Refer-Sub", 9 };
+
+               ast_debug(3, "Transfer accepted on channel %s\n", ast_channel_name(chan));
+
+               /* Check if response message */
+               if (event->type == PJSIP_EVENT_TSX_STATE && event->body.tsx_state.type == PJSIP_EVENT_RX_MSG) {
+                       rdata = event->body.tsx_state.src.rdata;
+
+                       /* Find Refer-Sub header */
+                       refer_sub = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &REFER_SUB, NULL);
+
+                       /* Check if subscription is suppressed. If it is, the far end will not terminate it,
+                        * and the subscription will remain active until it times out.  Terminating it here
+                        * eliminates the unnecessary timeout.
+                        */
+                       if (refer_sub && !pj_stricmp2(&refer_sub->hvalue, "false")) {
+                               /* Since no subscription is desired, assume that call has been transferred successfully. */
+                               /* Terminate subscription. */
+                               pjsip_evsub_terminate(sub, PJ_TRUE);
+                               res = -1;
+                       }
+               }
+       } else if (pjsip_evsub_get_state(sub) == PJSIP_EVSUB_STATE_ACTIVE ||
+                       pjsip_evsub_get_state(sub) == PJSIP_EVSUB_STATE_TERMINATED) {
+               /* Check for NOTIFY complete or error. */
+               pjsip_msg *msg;
+               pjsip_msg_body *body;
+               pjsip_status_line status_line = { .code = PJSIP_SC_NULL };
+               pj_bool_t is_last;
+               pj_status_t status;
+
+               if (event->type == PJSIP_EVENT_TSX_STATE && event->body.tsx_state.type == PJSIP_EVENT_RX_MSG) {
+                       pjsip_rx_data *rdata;
+
+                       rdata = event->body.tsx_state.src.rdata;
+                       msg = rdata->msg_info.msg;
+
+                       if (!pjsip_method_cmp(&msg->line.req.method, pjsip_get_notify_method())) {
+                               body = msg->body;
+                               if (body && !pj_stricmp2(&body->content_type.type, "message")
+                                       && !pj_stricmp2(&body->content_type.subtype, "sipfrag")) {
+                                       pjsip_parse_status_line((char *)body->data, body->len, &status_line);
+                               }
+                       }
+               } else {
+                       status_line.code = 500;
+                       status_line.reason = *pjsip_get_status_text(500);
+               }
+
+               is_last = (pjsip_evsub_get_state(sub) == PJSIP_EVSUB_STATE_TERMINATED);
+               /* If the status code is >= 200, the subscription is finished. */
+               if (status_line.code >= 200 || is_last) {
+                       res = -1;
+
+                       /* If the subscription has terminated, return AST_TRANSFER_SUCCESS for 2XX.
+                        * Any other status code returns AST_TRANSFER_FAILED.
+                        * The subscription should not terminate for any code < 200,
+                        * but if it does, that constitutes a failure. */
+                       if (status_line.code < 200 || status_line.code >= 300) {
+                               message = AST_TRANSFER_FAILED;
+                       }
+                       /* If subscription not terminated and subscription is finished (status code >= 200)
+                        * terminate it */
+                       if (!is_last) {
+                               pjsip_tx_data *tdata;
+
+                               status = pjsip_evsub_initiate(sub, pjsip_get_subscribe_method(), 0, &tdata);
+                               if (status == PJ_SUCCESS) {
+                                       pjsip_evsub_send_request(sub, tdata);
+                               }
+                       }
+                       /* Finished. Remove session from subscription */
+                       pjsip_evsub_set_mod_data(sub, refer_callback_module.id, NULL);
+                       ast_debug(3, "Transfer channel %s completed: %d %.*s (%s)\n",
+                                       ast_channel_name(chan),
+                                       status_line.code,
+                                       (int)status_line.reason.slen, status_line.reason.ptr,
+                                       (message == AST_TRANSFER_SUCCESS) ? "Success" : "Failure");
+               }
+       }
+
+       if (res) {
+               ast_queue_control_data(session->channel, AST_CONTROL_TRANSFER, &message, sizeof(message));
+       }
+}
+
 static void transfer_refer(struct ast_sip_session *session, const char *target)
 {
        pjsip_evsub *sub;
@@ -1902,14 +2027,20 @@ static void transfer_refer(struct ast_sip_session *session, const char *target)
        pjsip_tx_data *packet;
        const char *ref_by_val;
        char local_info[pj_strlen(&session->inv_session->dlg->local.info_str) + 1];
+       struct pjsip_evsub_user xfer_cb;
+
+       pj_bzero(&xfer_cb, sizeof(xfer_cb));
+       xfer_cb.on_evsub_state = &xfer_client_on_evsub_state;
 
-       if (pjsip_xfer_create_uac(session->inv_session->dlg, NULL, &sub) != PJ_SUCCESS) {
+       if (pjsip_xfer_create_uac(session->inv_session->dlg, &xfer_cb, &sub) != PJ_SUCCESS) {
                message = AST_TRANSFER_FAILED;
                ast_queue_control_data(session->channel, AST_CONTROL_TRANSFER, &message, sizeof(message));
 
                return;
        }
 
+       pjsip_evsub_set_mod_data(sub, refer_callback_module.id, session);
+
        if (pjsip_xfer_initiate(sub, pj_cstr(&tmp, target), &packet) != PJ_SUCCESS) {
                message = AST_TRANSFER_FAILED;
                ast_queue_control_data(session->channel, AST_CONTROL_TRANSFER, &message, sizeof(message));
@@ -1927,7 +2058,6 @@ static void transfer_refer(struct ast_sip_session *session, const char *target)
        }
 
        pjsip_xfer_send_request(sub, packet);
-       ast_queue_control_data(session->channel, AST_CONTROL_TRANSFER, &message, sizeof(message));
 }
 
 static int transfer(void *data)
@@ -3144,6 +3274,8 @@ static int load_module(void)
                goto end;
        }
 
+       ast_sip_register_service(&refer_callback_module);
+
        ast_sip_session_register_supplement(&chan_pjsip_supplement);
        ast_sip_session_register_supplement(&chan_pjsip_supplement_response);
 
@@ -3180,6 +3312,7 @@ end:
        ast_sip_session_unregister_supplement(&chan_pjsip_supplement_response);
        ast_sip_session_unregister_supplement(&chan_pjsip_supplement);
        ast_sip_session_unregister_supplement(&call_pickup_supplement);
+       ast_sip_unregister_service(&refer_callback_module);
        ast_custom_function_unregister(&dtmf_mode_function);
        ast_custom_function_unregister(&media_offer_function);
        ast_custom_function_unregister(&chan_pjsip_dial_contacts_function);
@@ -3205,6 +3338,8 @@ static int unload_module(void)
        ast_sip_session_unregister_supplement(&chan_pjsip_ack_supplement);
        ast_sip_session_unregister_supplement(&call_pickup_supplement);
 
+       ast_sip_unregister_service(&refer_callback_module);
+
        ast_custom_function_unregister(&dtmf_mode_function);
        ast_custom_function_unregister(&media_offer_function);
        ast_custom_function_unregister(&chan_pjsip_dial_contacts_function);
@@ -3223,5 +3358,5 @@ AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Channel Driver"
        .load = load_module,
        .unload = unload_module,
        .load_pri = AST_MODPRI_CHANNEL_DRIVER,
-       .requires = "res_pjsip,res_pjsip_session",
+       .requires = "res_pjsip,res_pjsip_session,res_pjsip_pubsub",
 );

diff --git a/doc/UPGRADE-staging/chan_pjsip_refer_fix.txt b/doc/UPGRADE-staging/chan_pjsip_refer_fix.txt
new file mode 100644 (file)
index 0000000..301930f
--- /dev/null
+++ b/doc/UPGRADE-staging/chan_pjsip_refer_fix.txt
@@ -0,0 +1,5 @@
+Subject: chan_pjsip
+Subject: Core
+
+res_pjsip_pubsub is now required so call transfer progress can be monitored
+and reported in the channel variable TRANSFERSTATUS.