res_pjsip_transport_management: Kill idle TCP connections.

"Idle" here means that someone connects to us and does not send a SIP
request. PJProject will not automatically time out such connections, so
it's up to Asterisk to do it instead.

When we receive an incoming TCP connection, we will start a timer
(equivalent to transaction timer D) waiting to receive an incoming
request. If we do not receive a request in that timeframe, then we will
shut down the TCP connection.

ASTERISK-25796 #close
Reported by George Joseph

AST-2016-005

Change-Id: I7b0d303e5d140d0ccaf2f7af562071e3d1130ac6

diff --git a/res/res_pjsip_transport_management.c b/res/res_pjsip_transport_management.c
index 43f77346c7eed05cbfc4e1abfda3e5518f186265..ddde69de630c1a81a171f3d9272544ee2c97b475 100644 (file)
--- a/res/res_pjsip_transport_management.c
+++ b/res/res_pjsip_transport_management.c
@@ -32,7 +32,9 @@
 #include "asterisk/astobj2.h"
 
 /*! \brief Number of buckets for keepalive transports */
-#define KEEPALIVE_TRANSPORTS_BUCKETS 53
+#define TRANSPORTS_BUCKETS 53
+
+#define IDLE_TIMEOUT (pjsip_cfg()->tsx.td)
 
 /*! \brief The keep alive packet to send */
 static const pj_str_t keepalive_packet = { "\r\n\r\n", 4 };
@@ -40,6 +42,9 @@ static const pj_str_t keepalive_packet = { "\r\n\r\n", 4 };
 /*! \brief Global container of active transports */
 static struct ao2_container *transports;
 
+/*! \brief Scheduler context for timing out connections with no data received */
+static struct ast_sched_context *sched;
+
 /*! \brief Thread keeping things alive */
 static pthread_t keepalive_thread = AST_PTHREADT_NULL;
 
@@ -49,24 +54,26 @@ static unsigned int keepalive_interval;
 /*! \brief Existing transport manager callback that we need to invoke */
 static pjsip_tp_state_callback tpmgr_state_callback;
 
-/*! \brief Structure for transport to be kept alive */
-struct keepalive_transport {
+/*! \brief Structure for transport to be monitored */
+struct monitored_transport {
        /*! \brief The underlying PJSIP transport */
        pjsip_transport *transport;
+       /*! \brief Non-zero if a PJSIP request was received */
+       int sip_received;
 };
 
 /*! \brief Callback function to send keepalive */
 static int keepalive_transport_cb(void *obj, void *arg, int flags)
 {
-       struct keepalive_transport *keepalive = obj;
+       struct monitored_transport *monitored = obj;
        pjsip_tpselector selector = {
                .type = PJSIP_TPSELECTOR_TRANSPORT,
-               .u.transport = keepalive->transport,
+               .u.transport = monitored->transport,
        };
 
        pjsip_tpmgr_send_raw(pjsip_endpt_get_tpmgr(ast_sip_get_pjsip_endpoint()),
-               keepalive->transport->key.type, &selector, NULL, keepalive_packet.ptr, keepalive_packet.slen,
-               &keepalive->transport->key.rem_addr, pj_sockaddr_get_len(&keepalive->transport->key.rem_addr),
+               monitored->transport->key.type, &selector, NULL, keepalive_packet.ptr, keepalive_packet.slen,
+               &monitored->transport->key.rem_addr, pj_sockaddr_get_len(&monitored->transport->key.rem_addr),
                NULL, NULL);
 
        return 0;
@@ -94,32 +101,60 @@ static void *keepalive_transport_thread(void *data)
        return NULL;
 }
 
+static int idle_sched_cb(const void *data)
+{
+       struct monitored_transport *keepalive = (struct monitored_transport *) data;
+       int sip_received = ast_atomic_fetchadd_int(&keepalive->sip_received, 0);
+
+       if (!sip_received) {
+               ast_log(LOG_NOTICE, "Shutting down transport '%s' since no request was received in %d seconds\n",
+                               keepalive->transport->info, IDLE_TIMEOUT);
+               pjsip_transport_shutdown(keepalive->transport);
+       }
+
+       ao2_ref(keepalive, -1);
+       return 0;
+}
+
 /*! \brief Destructor for keepalive transport */
-static void keepalive_transport_destroy(void *obj)
+static void monitored_transport_destroy(void *obj)
 {
-       struct keepalive_transport *keepalive = obj;
+       struct monitored_transport *keepalive = obj;
 
        pjsip_transport_dec_ref(keepalive->transport);
 }
 
 /*! \brief Callback invoked when transport changes occur */
-static void keepalive_transport_state_callback(pjsip_transport *transport, pjsip_transport_state state,
+static void monitored_transport_state_callback(pjsip_transport *transport, pjsip_transport_state state,
        const pjsip_transport_state_info *info)
 {
-       /* We only care about connection-oriented transports */
-       if (transport->flag & PJSIP_TRANSPORT_RELIABLE) {
-               struct keepalive_transport *keepalive;
+       /* We only care about reliable transports */
+       if (PJSIP_TRANSPORT_IS_RELIABLE(transport) &&
+                       (transport->dir == PJSIP_TP_DIR_INCOMING || keepalive_interval)) {
+               struct monitored_transport *monitored;
 
                switch (state) {
                case PJSIP_TP_STATE_CONNECTED:
-                       keepalive = ao2_alloc(sizeof(*keepalive), keepalive_transport_destroy);
-                       if (keepalive) {
-                               keepalive->transport = transport;
-                               pjsip_transport_add_ref(keepalive->transport);
-                               ao2_link(transports, keepalive);
-                               ao2_ref(keepalive, -1);
+                       monitored = ao2_alloc(sizeof(*monitored), monitored_transport_destroy);
+                       if (!monitored) {
+                               break;
+                       }
+                       monitored->transport = transport;
+                       pjsip_transport_add_ref(monitored->transport);
+                       ao2_link(transports, monitored);
+                       if (transport->dir == PJSIP_TP_DIR_INCOMING) {
+                               /* Let the scheduler inherit the reference from allocation */
+                               if (ast_sched_add_variable(sched, IDLE_TIMEOUT, idle_sched_cb, monitored, 1) < 0) {
+                                       ao2_unlink(transports, monitored);
+                                       ao2_ref(monitored, -1);
+                                       pjsip_transport_shutdown(transport);
+                               }
+                       } else {
+                               /* No scheduled task, so get rid of the allocation reference */
+                               ao2_ref(monitored, -1);
                        }
                        break;
+               case PJSIP_TP_STATE_SHUTDOWN:
                case PJSIP_TP_STATE_DISCONNECTED:
                        ao2_find(transports, transport->obj_name, OBJ_SEARCH_KEY | OBJ_NODATA | OBJ_UNLINK);
                        break;
@@ -134,10 +169,10 @@ static void keepalive_transport_state_callback(pjsip_transport *transport, pjsip
        }
 }
 
-/*! \brief Hashing function for keepalive transport */
-static int keepalive_transport_hash_fn(const void *obj, int flags)
+/*! \brief Hashing function for monitored transport */
+static int monitored_transport_hash_fn(const void *obj, int flags)
 {
-       const struct keepalive_transport *object;
+       const struct monitored_transport *object;
        const char *key;
 
        switch (flags & OBJ_SEARCH_MASK) {
@@ -156,11 +191,11 @@ static int keepalive_transport_hash_fn(const void *obj, int flags)
        return ast_str_hash(key);
 }
 
-/*! \brief Comparison function for keepalive transport */
-static int keepalive_transport_cmp_fn(void *obj, void *arg, int flags)
+/*! \brief Comparison function for monitored transport */
+static int monitored_transport_cmp_fn(void *obj, void *arg, int flags)
 {
-       const struct keepalive_transport *object_left = obj;
-       const struct keepalive_transport *object_right = arg;
+       const struct monitored_transport *object_left = obj;
+       const struct monitored_transport *object_right = arg;
        const char *right_key = arg;
        int cmp;
 
@@ -193,7 +228,6 @@ static int keepalive_transport_cmp_fn(void *obj, void *arg, int flags)
 static void keepalive_global_loaded(const char *object_type)
 {
        unsigned int new_interval = ast_sip_get_keep_alive_interval();
-       pjsip_tpmgr *tpmgr;
 
        if (new_interval) {
                keepalive_interval = new_interval;
@@ -209,40 +243,86 @@ static void keepalive_global_loaded(const char *object_type)
                return;
        }
 
-       transports = ao2_container_alloc(KEEPALIVE_TRANSPORTS_BUCKETS, keepalive_transport_hash_fn,
-               keepalive_transport_cmp_fn);
+       if (ast_pthread_create(&keepalive_thread, NULL, keepalive_transport_thread, NULL)) {
+               ast_log(LOG_ERROR, "Could not create thread for sending keepalive messages.\n");
+               ao2_ref(transports, -1);
+               return;
+       }
+}
+
+/*! \brief Observer which is used to update our interval when the global setting changes */
+static struct ast_sorcery_observer keepalive_global_observer = {
+       .loaded = keepalive_global_loaded,
+};
+
+/*!
+ * \brief
+ * On incoming TCP connections, when we receive a SIP request, we mark that we have
+ * received a valid SIP request. This way, we will not shut the transport down for
+ * idleness
+ */
+static pj_bool_t idle_monitor_on_rx_request(pjsip_rx_data *rdata)
+{
+       struct monitored_transport *idle_trans;
+
+       idle_trans = ao2_find(transports, rdata->tp_info.transport->obj_name, OBJ_SEARCH_KEY);
+       if (!idle_trans) {
+               return PJ_FALSE;
+       }
+
+       ast_atomic_fetchadd_int(&idle_trans->sip_received, +1);
+       ao2_ref(idle_trans, -1);
+
+       return PJ_FALSE;
+}
+
+static pjsip_module idle_monitor_module = {
+       .name = {"idle monitor module", 19},
+       .priority = PJSIP_MOD_PRIORITY_TRANSPORT_LAYER + 3,
+       .on_rx_request = idle_monitor_on_rx_request,
+};
+
+static int load_module(void)
+{
+       pjsip_tpmgr *tpmgr;
+
+       CHECK_PJSIP_MODULE_LOADED();
+
+       transports = ao2_container_alloc(TRANSPORTS_BUCKETS, monitored_transport_hash_fn,
+               monitored_transport_cmp_fn);
        if (!transports) {
                ast_log(LOG_ERROR, "Could not create container for transports to perform keepalive on.\n");
-               return;
+               return AST_MODULE_LOAD_DECLINE;
        }
 
        tpmgr = pjsip_endpt_get_tpmgr(ast_sip_get_pjsip_endpoint());
        if (!tpmgr) {
                ast_log(LOG_ERROR, "No transport manager to attach keepalive functionality to.\n");
                ao2_ref(transports, -1);
-               return;
+               return AST_MODULE_LOAD_DECLINE;
        }
 
-       if (ast_pthread_create(&keepalive_thread, NULL, keepalive_transport_thread, NULL)) {
-               ast_log(LOG_ERROR, "Could not create thread for sending keepalive messages.\n");
+       sched = ast_sched_context_create();
+       if (!sched) {
+               ast_log(LOG_ERROR, "Failed to create keepalive scheduler context.\n");
                ao2_ref(transports, -1);
-               return;
+               return AST_MODULE_LOAD_DECLINE;
        }
 
-       tpmgr_state_callback = pjsip_tpmgr_get_state_cb(tpmgr);
-       pjsip_tpmgr_set_state_cb(tpmgr, &keepalive_transport_state_callback);
-}
+       if (ast_sched_start_thread(sched)) {
+               ast_log(LOG_ERROR, "Failed to start keepalive scheduler thread\n");
+               ast_sched_context_destroy(sched);
+               ao2_ref(transports, -1);
+               return AST_MODULE_LOAD_DECLINE;
+       }
 
-/*! \brief Observer which is used to update our interval when the global setting changes */
-static struct ast_sorcery_observer keepalive_global_observer = {
-       .loaded = keepalive_global_loaded,
-};
+       ast_sip_register_service(&idle_monitor_module);
+
+       tpmgr_state_callback = pjsip_tpmgr_get_state_cb(tpmgr);
+       pjsip_tpmgr_set_state_cb(tpmgr, &monitored_transport_state_callback);
 
-static int load_module(void)
-{
        ast_sorcery_observer_add(ast_sip_get_sorcery(), "global", &keepalive_global_observer);
        ast_sorcery_reload_object(ast_sip_get_sorcery(), "global");
-       ast_module_ref(ast_module_info->self);
        return AST_MODULE_LOAD_SUCCESS;
 }
 
@@ -258,7 +338,7 @@ static int reload_module(void)
        return 0;
 }
 
-AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Stateful Connection Keepalive Support",
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Reliable Transport Management",
                .support_level = AST_MODULE_SUPPORT_CORE,
                .load = load_module,
                .reload = reload_module,