Starting to check NAS intgrity of GUTI attach.

srsepc/hdr/mme/s1ap.h

@@ -94,7 +94,7 @@ public:
   void store_tmp_ue_emm_ctx(const ue_emm_ctx_t &ue_ecm_ctx);
   bool get_tmp_ue_emm_ctx(uint32_t mme_ue_s1ap_id, ue_emm_ctx_t* ue_emm_ptr);
 
-  uint32_t allocate_m_tmsi(uint32_t mme_ue_s1ap_id);
+  uint32_t allocate_m_tmsi(uint64_t imsi);
 
   s1ap_args_t                    m_s1ap_args;
   srslte::log_filter            *m_s1ap_log;
@@ -103,7 +103,7 @@ public:
   s1ap_nas_transport*             m_s1ap_nas_transport;
   s1ap_ctx_mngmt_proc*             m_s1ap_ctx_mngmt_proc;
 
-  std::map<uint32_t, uint32_t>                      m_tmsi_to_s1ap_id;
+  std::map<uint32_t, uint64_t>                      m_tmsi_to_s1ap_id;
 
 private:
   s1ap();

srsepc/src/mme/s1ap.cc

@@ -38,7 +38,8 @@ boost::mutex   s1ap_instance_mutex;
 
 s1ap::s1ap():
   m_s1mme(-1),
-  m_next_mme_ue_s1ap_id(1)
+  m_next_mme_ue_s1ap_id(1),
+  m_next_m_tmsi(0xA000)
 {
 }
 
@@ -512,11 +513,11 @@ s1ap::activate_eps_bearer(uint32_t mme_s1ap_id, uint8_t ebi)
 }
 
 uint32_t
-s1ap::allocate_m_tmsi(uint32_t mme_ue_s1ap_id)
+s1ap::allocate_m_tmsi(uint64_t imsi)
 {
-  //uint32_t m_tmsi = m_next_m_tmsi++;
-  //m_tmsi_to_s1ap_id.insert(std::pair<uint32_t,uint32_t>(m_tmsi,mme_ue_s1ap_id));
-  uint32_t m_tmsi = 0x0123;
+  uint32_t m_tmsi = m_next_m_tmsi++;
+  m_tmsi_to_s1ap_id.insert(std::pair<uint32_t,uint32_t>(m_tmsi,imsi));
+  //uint32_t m_tmsi = 0x0123;
   return m_tmsi;
 }
 

srsepc/src/mme/s1ap_nas_transport.cc

@@ -342,7 +342,7 @@ s1ap_nas_transport::handle_nas_guti_attach_request(uint32_t enb_ue_s1ap_id,
 {
   //GUTI style attach
   uint32_t m_tmsi = attach_req.eps_mobile_id.guti.m_tmsi;
-  std::map<uint32_t,uint32_t>::iterator it = m_s1ap->m_tmsi_to_s1ap_id.find(m_tmsi);
+  std::map<uint32_t,uint64_t>::iterator it = m_s1ap->m_tmsi_to_s1ap_id.find(m_tmsi);
   if(it == m_s1ap->m_tmsi_to_s1ap_id.end())
   {
     //Could not find IMSI from M-TMSI, send Id request
@@ -411,21 +411,31 @@ s1ap_nas_transport::handle_nas_guti_attach_request(uint32_t enb_ue_s1ap_id,
   else{
     
     m_s1ap_log->console("Attach Request -- Found M-TMSI: %d\n",m_tmsi);
-    /*
-    ue_ctx_t *ue_ctx_ptr = m_s1ap->find_ue_ctx(it->second);
-    if(ue_ctx_ptr!=NULL)
+    //Get UE EMM context
+    ue_emm_ctx_t *ue_emm_ctx = find_ue_emm_ctx_from_imsi(it->second);
+    if(ue_emm_ctx_ptr!=NULL)
     {
-      m_s1ap_log->console("Found UE context. IMSI: %015lu\n",ue_ctx_ptr->imsi);
+      m_s1ap_log->console("Found UE context. IMSI: %015lu\n",ue_emm_ctx_ptr->imsi);
+      //Check NAS integrity
+      bool msg_valid = false;
+
+      if(msg_valid == true)
+      {
+        //Create session request
         m_mme_gtpc->send_create_session_request(ue_ctx_ptr->imsi, ue_ctx_ptr->mme_ue_s1ap_id);
         *reply_flag = false; //No reply needed
         return true;
       }
       else
+      {
+        //NAS integrity 
+      }
+    }
+    else
     {
       m_s1ap_log->error("Found M-TMSI but could not find UE context\n");
       return false;
     }
-    */
   }
   return true;
 }
@@ -1052,7 +1062,7 @@ s1ap_nas_transport::pack_attach_accept(ue_emm_ctx_t *ue_emm_ctx, ue_ecm_ctx_t *u
   attach_accept.guti.guti.mnc = mnc;
   attach_accept.guti.guti.mme_group_id = m_s1ap->m_s1ap_args.mme_group;
   attach_accept.guti.guti.mme_code = m_s1ap->m_s1ap_args.mme_code;
-  attach_accept.guti.guti.m_tmsi = m_s1ap->allocate_m_tmsi(ue_ecm_ctx->mme_ue_s1ap_id);
+  attach_accept.guti.guti.m_tmsi = m_s1ap->allocate_m_tmsi(ue_emm_ctx->imsi);
   m_s1ap_log->debug("Allocated GUTI: MCC %d, MNC %d, MME Group Id %d, MME Code 0x%x, M-TMSI 0x%x\n",
                     attach_accept.guti.guti.mcc,
                     attach_accept.guti.guti.mnc,