Remove all global variables in AMF_N2

src/amf-app/amf_n1.cpp

@@ -84,7 +84,6 @@ extern statistics stacs;
 extern void convert_string_2_hex(std::string& input, std::string& output);
 extern unsigned char* format_string_as_hex(std::string str);
 
-extern int ncc;
 Sha256 ctx;
 random_state_t random_state;
 static uint8_t no_random_delta = 0;
@@ -210,7 +209,6 @@ void amf_n1::handle_itti_message(itti_downlink_nas_transfer& itti_msg) {
         uint32_t ulcount =
             secu->ul_count.seq_num | (secu->ul_count.overflow << 8);
         Authentication_5gaka::derive_kgnb(0, 0x01, kamf, kgnb);
-        ncc = 1;
         print_buffer("amf_n1", "kamf", kamf, 32);
         // Authentication_5gaka::derive_kgnb(ulcount, 0x01, kamf, kgnb);
         bstring kgnb_bs = blk2bstr(kgnb, 32);
@@ -2201,7 +2199,6 @@ void amf_n1::security_mode_complete_handle(
     uint8_t kgnb[32];
     uint32_t ulcount = secu->ul_count.seq_num | (secu->ul_count.overflow << 8);
     Authentication_5gaka::derive_kgnb(0, 0x01, kamf, kgnb);
-    ncc = 1;
     print_buffer("amf_n1", "kamf", kamf, 32);
     // Authentication_5gaka::derive_kgnb(ulcount, 0x01, kamf, kgnb);
     bstring kgnb_bs = blk2bstr(kgnb, 32);

src/amf-app/amf_n2.cpp

@@ -69,10 +69,6 @@ extern statistics stacs;
 extern void print_buffer(
     const std::string app, const std::string commit, uint8_t* buf, int len);
 
-sctp_assoc_id_t downlink_sctp_assoc_id = 0;
-sctp_assoc_id_t source_assoc_id        = 0;
-int ncc                                = 0;
-
 void amf_n2_task(void*);
 
 //------------------------------------------------------------------------------
@@ -689,6 +685,7 @@ void amf_n2::handle_itti_message(itti_initial_context_setup_request& itti_msg) {
         "Illegal UE with ran_ue_ngap_id (0x%x)", itti_msg.ran_ue_ngap_id);
     return;
   }
+  unc.get()->ncc = 1;
   std::shared_ptr<gnb_context> gc;
   gc = assoc_id_2_gnb_context(unc.get()->gnb_assoc_id);
   if (gc.get() == nullptr) {
@@ -1046,10 +1043,8 @@ void amf_n2::handle_itti_message(
 //------------------------------------------------------------------------------
 void amf_n2::handle_itti_message(itti_handover_required& itti_msg) {
   // TODO: Experimental procedure, to be tested
-  ncc++;  // TODO: to be verified
   unsigned long amf_ue_ngap_id = itti_msg.handoverReq->getAmfUeNgapId();
   uint32_t ran_ue_ngap_id      = itti_msg.handoverReq->getRanUeNgapId();
-  source_assoc_id = itti_msg.assoc_id;
 
   std::shared_ptr<gnb_context> gc = {};
   if (!is_assoc_id_2_gnb_context(itti_msg.assoc_id)) {
@@ -1066,6 +1061,9 @@ void amf_n2::handle_itti_message(itti_handover_required& itti_msg) {
     return;
   }
   unc                     = ran_ue_id_2_ue_ngap_context(ran_ue_ngap_id);
+  unc.get()->gnb_assoc_id = itti_msg.assoc_id;
+  unc.get()->ncc++;
+  unc.get()->ng_ue_state = NGAP_UE_HANDOVER;
 
   if (unc.get()->amf_ue_ngap_id != amf_ue_ngap_id) {
     Logger::amf_n2().error(
@@ -1178,10 +1176,10 @@ void amf_n2::handle_itti_message(itti_handover_required& itti_msg) {
   Logger::amf_n1().debug("uplink count(%d)", secu->ul_count.seq_num);
   uint8_t knh[32];
   Authentication_5gaka::handover_ncc_derive_knh(
-      ulcount, 0x01, kamf, kgnb, knh, ncc);
+      ulcount, 0x01, kamf, kgnb, knh, unc.get()->ncc);
   bstring knh_bs = blk2bstr(knh, 32);
   handoverrequest->setSecurityContext(
-      ncc /*NCC count*/, (uint8_t*) bdata(knh_bs));
+      unc.get()->ncc /*NCC count*/, (uint8_t*) bdata(knh_bs));
 
   string supi = "imsi-" + nc.get()->imsi;
 
@@ -1225,7 +1223,7 @@ void amf_n2::handle_itti_message(itti_handover_required& itti_msg) {
   bstring b        = blk2bstr(buffer, encoded_size);
   std::shared_ptr<gnb_context> gc_target = {};
   gc_target                      = gnb_id_2_gnb_context(gnbid->getValue());
-  downlink_sctp_assoc_id = gc_target.get()->sctp_assoc_id;
+  unc.get()->target_gnb_assoc_id = gc_target.get()->sctp_assoc_id;
   sctp_s_38412.sctp_send_msg(gc_target.get()->sctp_assoc_id, 0, &b);
 }
 
@@ -1253,7 +1251,7 @@ void amf_n2::handle_itti_message(itti_handover_request_Ack& itti_msg) {
     return;
   }
   unc = amf_ue_id_2_ue_ngap_context(amf_ue_ngap_id);
-  unc.get()->ran_ue_ngap_id_temp = ran_ue_ngap_id;  // store target RAN ID
+  unc.get()->target_ran_ue_ngap_id = ran_ue_ngap_id;  // store target RAN ID
 
   std::vector<PDUSessionResourceAdmittedItem_t> list;
   if (!itti_msg.handoverrequestAck->getPDUSessionResourceAdmittedList(list)) {
@@ -1377,9 +1375,10 @@ void amf_n2::handle_itti_message(itti_handover_notify& itti_msg) {
   // TODO: Experimental procedure, to be tested
   unsigned long amf_ue_ngap_id = itti_msg.handovernotify->getAmfUeNgapId();
   uint32_t ran_ue_ngap_id      = itti_msg.handovernotify->getRanUeNgapId();
-  Logger::amf_n2().error(
+  Logger::amf_n2().debug(
       "Handover Notify ran_ue_ngap_id (0x%d) amf_ue_ngap_id (%lu)",
       ran_ue_ngap_id, amf_ue_ngap_id);
+
   if (!is_assoc_id_2_gnb_context(itti_msg.assoc_id)) {
     Logger::amf_n2().error(
         "gNB with assoc_id (%d) is illegal", itti_msg.assoc_id);
@@ -1414,9 +1413,9 @@ void amf_n2::handle_itti_message(itti_handover_notify& itti_msg) {
   bstring b        = blk2bstr(buffer, encoded_size);
   std::shared_ptr<nas_context> nc =
       amf_n1_inst->amf_ue_id_2_nas_context(amf_ue_ngap_id);
-  std::shared_ptr<ue_ngap_context> ngc =
-      ran_ue_id_2_ue_ngap_context(nc.get()->ran_ue_ngap_id);
-  sctp_s_38412.sctp_send_msg(source_assoc_id, 0, &b);
+  // std::shared_ptr<ue_ngap_context> ngc =
+  //     ran_ue_id_2_ue_ngap_context(nc.get()->ran_ue_ngap_id);
+  sctp_s_38412.sctp_send_msg(unc.get()->gnb_assoc_id, 0, &b);
 
   /*std::shared_ptr<nas_context> nc =
   amf_n1_inst->amf_ue_id_2_nas_context(amf_ue_ngap_id); string supi = "imsi-" +
@@ -1436,9 +1435,9 @@ void amf_n2::handle_itti_message(itti_handover_notify& itti_msg) {
   }
   unc                       = amf_ue_id_2_ue_ngap_context(amf_ue_ngap_id);
   unc.get()->ran_ue_ngap_id = ran_ue_ngap_id;  // store new RAN ID
-  unc.get()->ran_ue_ngap_id_temp = 0;               // Clear target RAN ID
+  unc.get()->target_ran_ue_ngap_id = 0;        // Clear target RAN ID
   unc.get()->ng_ue_state           = NGAP_UE_CONNECTED;
-  unc.get()->gnb_assoc_id        = ngc.get()->gnb_assoc_id;
+  unc.get()->gnb_assoc_id          = itti_msg.assoc_id;  // update serving gNB
   set_ran_ue_ngap_id_2_ue_ngap_context(ran_ue_ngap_id, unc);
 }
 
@@ -1500,15 +1499,15 @@ void amf_n2::handle_itti_message(itti_uplinkranstatsutransfer& itti_msg) {
       std::make_unique<DownlinkRANStatusTransfer>();
   downLinkranstatustransfer->setmessagetype();
   downLinkranstatustransfer->setAmfUeNgapId(amf_ue_ngap_id);
-  downLinkranstatustransfer->setRanUeNgapId(unc.get()->ran_ue_ngap_id_temp);
+  downLinkranstatustransfer->setRanUeNgapId(unc.get()->target_ran_ue_ngap_id);
   downLinkranstatustransfer->setRANStatusTransfer_TransparentContainer(
       amf_drb_id, amf_ul_pdcp, amf_hfn_ul_pdcp, amf_dl_pdcp, amf_hfn_dl_pdcp);
   uint8_t buffer[1024];
   int encode_size = downLinkranstatustransfer->encodetobuffer(buffer, 1024);
   bstring b       = blk2bstr(buffer, encode_size);
   // std::shared_ptr<ue_ngap_context> ngc =
-  // ran_ue_id_2_ue_ngap_context(unc.get()->ran_ue_ngap_id_temp );
-  sctp_s_38412.sctp_send_msg(downlink_sctp_assoc_id, 0, &b);
+  // ran_ue_id_2_ue_ngap_context(unc.get()->target_ran_ue_ngap_id );
+  sctp_s_38412.sctp_send_msg(unc.get()->target_gnb_assoc_id, 0, &b);
 }
 
 // Context management functions

src/contexts/ue_ngap_context.hpp

@@ -48,18 +48,20 @@ class ue_ngap_context {
  public:
   uint32_t ran_ue_ngap_id;         // 32bits
   long amf_ue_ngap_id : 40;        // 40bits
-  uint32_t ran_ue_ngap_id_temp;  // 32bits, for HO
+  uint32_t target_ran_ue_ngap_id;  // 32bits, for HO
 
   sctp_stream_id_t sctp_stream_recv;  // used to decide which ue in gNB
   sctp_stream_id_t sctp_stream_send;  // used to decide which ue in gNB
 
   sctp_assoc_id_t gnb_assoc_id;  // to find which gnb this UE belongs to
+  sctp_assoc_id_t target_gnb_assoc_id;
 
   bool ueContextRequest;
   uint32_t s_tmsi_5g;
 
   // state management, ue status over the air
   ng_ue_state_t ng_ue_state;
+  uint8_t ncc;  // Next Hop Chaining Counter
 };
 
 #endif