Implement removal of endpoint

For unit testing, allow to remove endpoints such that we could reuse a
port/IP combination.

The function does not take care of endpoints that are still "dangling",
it is the user's responsibility to remove all existing TEIDs.

openair3/ocp-gtpu/gtp_itf.cpp

@@ -613,6 +613,20 @@ instance_t gtpv1Init(openAddr_t context)
   return id;
 }
 
+/* \brief remove the GTP instance from the list of instances. Does not make an
+ * attempt to free corresponding TEIDs, as we have many and will simply not
+ * reuse it later. */
+int gtpv1Term(instance_t instance)
+{
+  pthread_mutex_lock(&globGtp.gtp_lock);
+  getInstRetInt(compatInst(instance));
+  gtpv1uReceiverCancel(inst->thrData.t);
+  close(instance);
+  globGtp.instances.erase(instance);
+  pthread_mutex_unlock(&globGtp.gtp_lock);
+  return 0;
+}
+
 void GtpuUpdateTunnelOutgoingAddressAndTeid(instance_t instance,
                                             ue_id_t ue_id,
                                             ebi_t bearer_id,

openair3/ocp-gtpu/gtp_itf.h

@@ -130,6 +130,7 @@ typedef struct gtpv1u_gnb_delete_tunnel_req_s gtpv1u_gnb_delete_tunnel_req_t;
                                      size_t len);
 
   instance_t gtpv1Init(openAddr_t context);
+  int gtpv1Term(instance_t inst);
   void *gtpv1uTask(void *args);
 
 #ifdef __cplusplus

openair3/ocp-gtpu/tests/test_gtp.cpp

@@ -136,6 +136,11 @@ static void run_basic_test(uint32_t ue_id,
   EXPECT_EQ(ret, 0);
   ret = newGtpuDeleteAllTunnels(ep2, ue_id);
   EXPECT_EQ(ret, 0);
+
+  ret = gtpv1Term(ep1);
+  EXPECT_EQ(ret, 0);
+  ret = gtpv1Term(ep2);
+  EXPECT_EQ(ret, 0);
 }
 
 static int recv_count_qfi = 0;