This commit rejects an UE that connects by sending RRCConnectionRequest with S-TMSI.

The observed behavior (samsung phone, lte dongle, sequans box) is that the UE
keeps connecting over and over again.

openair2/RRC/LITE/MESSAGES/asn1_msg.c

@@ -2110,6 +2110,67 @@ do_RRCConnectionReestablishmentReject(
   return((enc_rval.encoded+7)/8);
 }
 
+//------------------------------------------------------------------------------
+uint8_t
+do_RRCConnectionReject(
+  uint8_t                    Mod_id,
+  uint8_t*                   const buffer)
+//------------------------------------------------------------------------------
+{
+
+  asn_enc_rval_t enc_rval;
+
+  DL_CCCH_Message_t dl_ccch_msg;
+  RRCConnectionReject_t *rrcConnectionReject;
+
+  memset((void *)&dl_ccch_msg,0,sizeof(DL_CCCH_Message_t));
+  dl_ccch_msg.message.present           = DL_CCCH_MessageType_PR_c1;
+  dl_ccch_msg.message.choice.c1.present = DL_CCCH_MessageType__c1_PR_rrcConnectionReject;
+  rrcConnectionReject                   = &dl_ccch_msg.message.choice.c1.choice.rrcConnectionReject;
+
+  // RRCConnectionReject
+  rrcConnectionReject->criticalExtensions.present = RRCConnectionReject__criticalExtensions_PR_c1;
+  rrcConnectionReject->criticalExtensions.choice.c1.present = RRCConnectionReject__criticalExtensions__c1_PR_rrcConnectionReject_r8;
+  /* let's put a wait time of 1s for the moment */
+  rrcConnectionReject->criticalExtensions.choice.c1.choice.rrcConnectionReject_r8.waitTime = 1;
+
+#ifdef XER_PRINT
+  xer_fprint(stdout, &asn_DEF_DL_CCCH_Message, (void*)&dl_ccch_msg);
+#endif
+  enc_rval = uper_encode_to_buffer(&asn_DEF_DL_CCCH_Message,
+                                   (void*)&dl_ccch_msg,
+                                   buffer,
+                                   100);
+  AssertFatal (enc_rval.encoded > 0, "ASN1 message encoding failed (%s, %ld)!\n",
+               enc_rval.failed_type->name, enc_rval.encoded);
+
+#if defined(ENABLE_ITTI)
+# if !defined(DISABLE_XER_SPRINT)
+  {
+    char        message_string[20000];
+    size_t      message_string_size;
+
+    if ((message_string_size = xer_sprint(message_string, sizeof(message_string), &asn_DEF_DL_CCCH_Message, (void *) &dl_ccch_msg)) > 0) {
+      MessageDef *msg_p;
+
+      msg_p = itti_alloc_new_message_sized (TASK_RRC_ENB, RRC_DL_CCCH, message_string_size + sizeof (IttiMsgText));
+      msg_p->ittiMsg.rrc_dl_ccch.size = message_string_size;
+      memcpy(&msg_p->ittiMsg.rrc_dl_ccch.text, message_string, message_string_size);
+
+      itti_send_msg_to_task(TASK_UNKNOWN, Mod_id, msg_p);
+    }
+  }
+# endif
+#endif
+
+#ifdef USER_MODE
+  LOG_D(RRC,"RRCConnectionReject Encoded %d bits (%d bytes)\n",
+        enc_rval.encoded,(enc_rval.encoded+7)/8);
+#endif
+
+  return((enc_rval.encoded+7)/8);
+}
+
 uint8_t do_RRCConnectionRelease(
   uint8_t                             Mod_id,
   uint8_t                            *buffer,

openair2/RRC/LITE/MESSAGES/asn1_msg.h

@@ -218,6 +218,16 @@ do_RRCConnectionReestablishmentReject(
     uint8_t                    Mod_id,
     uint8_t*                   const buffer);
 
+/**
+\brief Generate an RRCConnectionReject DL-CCCH-Message (eNB).
+@param Mod_id Module ID of eNB
+@param buffer Pointer to PER-encoded ASN.1 description of DL-CCCH-Message PDU
+@returns Size of encoded bit stream in bytes*/
+uint8_t
+do_RRCConnectionReject(
+    uint8_t                    Mod_id,
+    uint8_t*                   const buffer);
+
 /**
 \brief Generate an RRCConnectionRequest UL-CCCH-Message (UE) based on random string or S-TMSI.  This
 routine only generates an mo-data establishment cause.

openair2/RRC/LITE/rrc_eNB.c

@@ -963,6 +963,49 @@ rrc_eNB_generate_UECapabilityEnquiry(
 
 }
 
+//-----------------------------------------------------------------------------
+void
+rrc_eNB_generate_RRCConnectionReject(
+  const protocol_ctxt_t* const ctxt_pP,
+  rrc_eNB_ue_context_t*          const ue_context_pP,
+  const int                    CC_id
+)
+//-----------------------------------------------------------------------------
+{
+#ifdef RRC_MSG_PRINT
+  int                                 cnt;
+#endif
+
+  eNB_rrc_inst[ctxt_pP->module_id].carrier[CC_id].Srb0.Tx_buffer.payload_size =
+    do_RRCConnectionReject(ctxt_pP->module_id,
+                          (uint8_t*) eNB_rrc_inst[ctxt_pP->module_id].carrier[CC_id].Srb0.Tx_buffer.Payload);
+
+#ifdef RRC_MSG_PRINT
+  LOG_F(RRC,"[MSG] RRCConnectionReject\n");
+
+  for (cnt = 0; cnt < eNB_rrc_inst[ctxt_pP->module_id].carrier[CC_id].Srb0.Tx_buffer.payload_size; cnt++) {
+    LOG_F(RRC,"%02x ", ((uint8_t*)eNB_rrc_inst[ctxt_pP->module_id].Srb0.Tx_buffer.Payload)[cnt]);
+  }
+
+  LOG_F(RRC,"\n");
+#endif
+
+  MSC_LOG_TX_MESSAGE(
+    MSC_RRC_ENB,
+    MSC_RRC_UE,
+    eNB_rrc_inst[ctxt_pP->module_id].carrier[CC_id].Srb0.Tx_buffer.Header,
+    eNB_rrc_inst[ctxt_pP->module_id].carrier[CC_id].Srb0.Tx_buffer.payload_size,
+    MSC_AS_TIME_FMT" RRCConnectionReject UE %x size %u",
+    MSC_AS_TIME_ARGS(ctxt_pP),
+    ue_context_pP == NULL ? -1 : ue_context_pP->ue_context.rnti,
+    eNB_rrc_inst[ctxt_pP->module_id].carrier[CC_id].Srb0.Tx_buffer.payload_size);
+
+  LOG_I(RRC,
+        PROTOCOL_RRC_CTXT_UE_FMT" [RAPROC] Logical Channel DL-CCCH, Generating RRCConnectionReject (bytes %d)\n",
+        PROTOCOL_RRC_CTXT_UE_ARGS(ctxt_pP),
+        eNB_rrc_inst[ctxt_pP->module_id].carrier[CC_id].Srb0.Tx_buffer.payload_size);
+}
+
 //-----------------------------------------------------------------------------
 void
 rrc_eNB_generate_RRCConnectionReestablishmentReject(
@@ -3627,8 +3670,15 @@ rrc_eNB_decode_ccch(
       } else {
         rrcConnectionRequest = &ul_ccch_msg->message.choice.c1.choice.rrcConnectionRequest.criticalExtensions.choice.rrcConnectionRequest_r8;
         {
-          AssertFatal(rrcConnectionRequest->ue_Identity.present == InitialUE_Identity_PR_randomValue,
-                      "unsupported InitialUE-Identity in RRCConnectionRequest");
+          if (rrcConnectionRequest->ue_Identity.present != InitialUE_Identity_PR_randomValue) {
+            LOG_E(RRC,
+                  PROTOCOL_RRC_CTXT_UE_FMT" RRCConnectionRequest with S-TMSI not supported yet, let's reject the UE\n",
+                  PROTOCOL_RRC_CTXT_UE_ARGS(ctxt_pP));
+            rrc_eNB_generate_RRCConnectionReject(ctxt_pP,
+                             rrc_eNB_get_ue_context(&eNB_rrc_inst[ctxt_pP->module_id], ctxt_pP->rnti),
+                             CC_id);
+            break;
+          }
           AssertFatal(rrcConnectionRequest->ue_Identity.choice.randomValue.size == 5,
                       "wrong InitialUE-Identity randomValue size, expected 5, provided %d",
                       rrcConnectionRequest->ue_Identity.choice.randomValue.size);