S1AP: Only register MME if we do not know it yet

openair3/S1AP/s1ap_eNB.c

@@ -220,8 +220,21 @@ void s1ap_eNB_handle_register_eNB(instance_t instance, s1ap_register_enb_req_t *
 
   /* Trying to connect to provided list of MME ip address */
   for (index = 0; index < s1ap_register_eNB->nb_mme; index++) {
+    net_ip_address_t *mme_ip = &s1ap_register_eNB->mme_ip_address[index];
+    struct s1ap_eNB_mme_data_s *mme = NULL;
+    RB_FOREACH(mme, s1ap_mme_map, &new_instance->s1ap_mme_head) {
+      /* Compare whether IPv4 and IPv6 information is already present, in which
+       * wase we do not register again */
+      if (mme->mme_s1_ip.ipv4 == mme_ip->ipv4 && (!mme_ip->ipv4
+              || strncmp(mme->mme_s1_ip.ipv4_address, mme_ip->ipv4_address, 16) == 0)
+          && mme->mme_s1_ip.ipv6 == mme_ip->ipv6 && (!mme_ip->ipv6
+              || strncmp(mme->mme_s1_ip.ipv6_address, mme_ip->ipv6_address, 46) == 0))
+        break;
+    }
+    if (mme)
+      continue;
     s1ap_eNB_register_mme(new_instance,
-                          &s1ap_register_eNB->mme_ip_address[index],
+                          mme_ip,
                           &s1ap_register_eNB->enb_ip_address,
                           s1ap_register_eNB->sctp_in_streams,
                           s1ap_register_eNB->sctp_out_streams,