From e5a83474cc6a78a504f4a1916e26cbbcba4d2304 Mon Sep 17 00:00:00 2001
From: Pedro Alvarez <pedro.alvarez@softwareradiosystems.com>
Date: Thu, 1 Jul 2021 12:34:00 +0100
Subject: [PATCH] Added max_s1_setup retries option to S1AP

---
 lib/src/common/network_utils.cc |  2 ++
 srsenb/hdr/stack/s1ap/s1ap.h    |  4 +++-
 srsenb/src/stack/s1ap/s1ap.cc   | 18 ++++++++++++++----
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/lib/src/common/network_utils.cc b/lib/src/common/network_utils.cc
index e6dc6a97b..29759d153 100644
--- a/lib/src/common/network_utils.cc
+++ b/lib/src/common/network_utils.cc
@@ -234,11 +234,13 @@ bool connect_to(int fd, const char* dest_addr_str, int dest_port, sockaddr_in* d
   if (dest_sockaddr != nullptr) {
     *dest_sockaddr = sockaddr_tmp;
   }
+
   if (connect(fd, (const struct sockaddr*)&sockaddr_tmp, sizeof(sockaddr_tmp)) == -1) {
     srslog::fetch_basic_logger(LOGSERVICE).info("Failed to establish socket connection to %s", dest_addr_str);
     perror("connect()");
     return false;
   }
+
   return true;
 }
 
diff --git a/srsenb/hdr/stack/s1ap/s1ap.h b/srsenb/hdr/stack/s1ap/s1ap.h
index 79b58a56a..0f37ef5ae 100644
--- a/srsenb/hdr/stack/s1ap/s1ap.h
+++ b/srsenb/hdr/stack/s1ap/s1ap.h
@@ -122,6 +122,7 @@ private:
   rrc_interface_s1ap*         rrc = nullptr;
   s1ap_args_t                 args;
   srslog::basic_logger&       logger;
+  srslog::log_channel&        alarms_channel;
   srsran::task_sched_handle   task_sched;
   srsran::task_queue_handle   mme_task_queue;
   srsran::socket_manager_itf* rx_socket_handler;
@@ -329,8 +330,9 @@ private:
     srsran::proc_outcome_t init();
     srsran::proc_outcome_t step() { return srsran::proc_outcome_t::yield; }
     srsran::proc_outcome_t react(const s1setupresult& event);
-    void                   then(const srsran::proc_state_t& result) const;
+    void                   then(const srsran::proc_state_t& result);
     const char*            name() const { return "MME Connection"; }
+    uint16_t               connect_count = 0;
 
   private:
     srsran::proc_outcome_t start_mme_connection();
diff --git a/srsenb/src/stack/s1ap/s1ap.cc b/srsenb/src/stack/s1ap/s1ap.cc
index f64b6a2a9..d1af2535d 100644
--- a/srsenb/src/stack/s1ap/s1ap.cc
+++ b/srsenb/src/stack/s1ap/s1ap.cc
@@ -220,6 +220,7 @@ void s1ap::ue::ho_prep_proc_t::then(const srsran::proc_state_t& result)
 srsran::proc_outcome_t s1ap::s1_setup_proc_t::init()
 {
   procInfo("Starting new MME connection.");
+  connect_count++;
   return start_mme_connection();
 }
 
@@ -265,7 +266,7 @@ srsran::proc_outcome_t s1ap::s1_setup_proc_t::react(const srsenb::s1ap::s1_setup
   return srsran::proc_outcome_t::error;
 }
 
-void s1ap::s1_setup_proc_t::then(const srsran::proc_state_t& result) const
+void s1ap::s1_setup_proc_t::then(const srsran::proc_state_t& result)
 {
   if (result.is_error()) {
     procInfo("Failed to initiate S1 connection. Attempting reconnection in %d seconds",
@@ -276,7 +277,12 @@ void s1ap::s1_setup_proc_t::then(const srsran::proc_state_t& result) const
     s1ap_ptr->mme_socket.close();
     procInfo("S1AP socket closed.");
     s1ap_ptr->mme_connect_timer.run();
+    if (connect_count > s1ap_ptr->args.max_s1_setup_retries) {
+      s1ap_ptr->alarms_channel("s1apError");
+    }
     // Try again with in 10 seconds
+  } else {
+    connect_count = 0;
   }
 }
 
@@ -287,7 +293,11 @@ void s1ap::s1_setup_proc_t::then(const srsran::proc_state_t& result) const
 s1ap::s1ap(srsran::task_sched_handle   task_sched_,
            srslog::basic_logger&       logger,
            srsran::socket_manager_itf* rx_socket_handler_) :
-  s1setup_proc(this), logger(logger), task_sched(task_sched_), rx_socket_handler(rx_socket_handler_)
+  s1setup_proc(this),
+  logger(logger),
+  task_sched(task_sched_),
+  rx_socket_handler(rx_socket_handler_),
+  alarms_channel(srslog::fetch_log_channel("alarms"))
 {
   mme_task_queue = task_sched.make_task_queue();
 }
@@ -303,7 +313,7 @@ int s1ap::init(const s1ap_args_t& args_, rrc_interface_s1ap* rrc_)
   mme_connect_timer    = task_sched.get_unique_timer();
   auto mme_connect_run = [this](uint32_t tid) {
     if (s1setup_proc.is_busy()) {
-      logger.error("Failed to initiate S1Setup procedure.");
+      logger.error("Failed to initiate S1Setup procedure: procedure is busy.");
     }
     s1setup_proc.launch();
   };
@@ -321,7 +331,7 @@ int s1ap::init(const s1ap_args_t& args_, rrc_interface_s1ap* rrc_)
   running = true;
   // starting MME connection
   if (not s1setup_proc.launch()) {
-    logger.error("Failed to initiate S1Setup procedure.");
+    logger.error("Failed to initiate S1Setup procedure: error launching procedure.");
   }
 
   return SRSRAN_SUCCESS;