Fixed case where calling gw::setup_if_addr after ue attachment would spawn a new thread without closing the current one.

This would end up being a resource leak as the number of threads grow forever until the application crashes.

srsue/hdr/stack/upper/gw.h

@@ -54,14 +54,9 @@ public:
   void write_pdu_mch(uint32_t lcid, srsran::unique_byte_buffer_t pdu);
 
   // NAS interface
-  int  setup_if_addr(uint32_t eps_bearer_id,
+  int  setup_if_addr(uint32_t eps_bearer_id, uint8_t pdn_type, uint32_t ip_addr, uint8_t* ipv6_if_addr, char* err_str);
-                     uint8_t  pdn_type,
-                     uint32_t ip_addr,
-                     uint8_t* ipv6_if_addr,
-                     char*    err_str);
   int  deactivate_eps_bearer(const uint32_t eps_bearer_id);
-  int  apply_traffic_flow_template(const uint8_t&                                 eps_bearer_id,
+  int  apply_traffic_flow_template(const uint8_t& eps_bearer_id, const LIBLTE_MME_TRAFFIC_FLOW_TEMPLATE_STRUCT* tft);
-                                   const LIBLTE_MME_TRAFFIC_FLOW_TEMPLATE_STRUCT* tft);
   void set_test_loop_mode(const test_loop_mode_state_t mode, const uint32_t ip_pdu_delay_ms);
 
   // RRC interface
@@ -75,13 +70,13 @@ private:
 
   gw_args_t args = {};
 
-  std::atomic<bool> running      = {false};
+  std::atomic<bool> running    = {false};
-  bool         run_enable   = false;
+  std::atomic<bool> run_enable = {false};
-  int32_t      netns_fd     = 0;
+  int32_t           netns_fd   = 0;
-  int32_t      tun_fd       = 0;
+  int32_t           tun_fd     = 0;
-  struct ifreq ifr          = {};
+  struct ifreq      ifr        = {};
-  int32_t      sock         = 0;
+  int32_t           sock       = 0;
-  bool         if_up        = false;
+  bool              if_up      = false;
 
   static const int NOT_ASSIGNED          = -1;
   int32_t          default_eps_bearer_id = NOT_ASSIGNED;

srsue/src/stack/upper/gw.cc

@@ -179,6 +179,13 @@ void gw::write_pdu_mch(uint32_t lcid, srsran::unique_byte_buffer_t pdu)
 int gw::setup_if_addr(uint32_t eps_bearer_id, uint8_t pdn_type, uint32_t ip_addr, uint8_t* ipv6_if_addr, char* err_str)
 {
   int err;
+
+  // Make sure the worker thread is terminated before spawning a new one.
+  if (running) {
+    run_enable = false;
+    thread_cancel();
+    wait_thread_finish();
+  }
   if (pdn_type == LIBLTE_MME_PDN_TYPE_IPV4 || pdn_type == LIBLTE_MME_PDN_TYPE_IPV4V6) {
     err = setup_if_addr4(ip_addr, err_str);
     if (err != SRSRAN_SUCCESS) {
@@ -195,6 +202,7 @@ int gw::setup_if_addr(uint32_t eps_bearer_id, uint8_t pdn_type, uint32_t ip_addr
   default_eps_bearer_id = static_cast<int>(eps_bearer_id);
 
   // Setup a thread to receive packets from the TUN device
+  run_enable = true;
   start(GW_THREAD_PRIO);
 
   return SRSRAN_SUCCESS;
@@ -446,6 +454,9 @@ int gw::setup_if_addr4(uint32_t ip_addr, char* err_str)
       }
     }
 
+    if (sock > 0) {
+      close(sock);
+    }
     // Setup the IP address
     sock                                                  = socket(AF_INET, SOCK_DGRAM, 0);
     ifr.ifr_addr.sa_family                                = AF_INET;
@@ -495,6 +506,9 @@ int gw::setup_if_addr6(uint8_t* ipv6_if_id, char* err_str)
       }
     }
 
+    if (sock > 0) {
+      close(sock);
+    }
     // Setup the IP address
     sock                   = socket(AF_INET6, SOCK_DGRAM, 0);
     ifr.ifr_addr.sa_family = AF_INET6;