add basic handling for deactivating eps bearer

lib/include/srslte/asn1/liblte_mme.h

@@ -3733,7 +3733,10 @@ typedef struct{
     bool                                      protocol_cnfg_opts_present;
 }LIBLTE_MME_DEACTIVATE_EPS_BEARER_CONTEXT_ACCEPT_MSG_STRUCT;
 // Functions
-LIBLTE_ERROR_ENUM liblte_mme_pack_deactivate_eps_bearer_context_accept_msg(LIBLTE_MME_DEACTIVATE_EPS_BEARER_CONTEXT_ACCEPT_MSG_STRUCT *deact_eps_bearer_context_accept,
+LIBLTE_ERROR_ENUM liblte_mme_pack_deactivate_eps_bearer_context_accept_msg(
+    LIBLTE_MME_DEACTIVATE_EPS_BEARER_CONTEXT_ACCEPT_MSG_STRUCT* deact_eps_bearer_context_accept,
+    uint8                                                       sec_hdr_type,
+    uint32                                                      count,
     LIBLTE_BYTE_MSG_STRUCT*                                     msg);
 LIBLTE_ERROR_ENUM liblte_mme_unpack_deactivate_eps_bearer_context_accept_msg(LIBLTE_BYTE_MSG_STRUCT                                     *msg,
                                                                              LIBLTE_MME_DEACTIVATE_EPS_BEARER_CONTEXT_ACCEPT_MSG_STRUCT *deact_eps_bearer_context_accept);

lib/src/asn1/liblte_mme.cc

@@ -9810,15 +9810,29 @@ LIBLTE_ERROR_ENUM liblte_mme_unpack_bearer_resource_modification_request_msg(LIB
 
     Document Reference: 24.301 v10.2.0 Section 8.3.11
 *********************************************************************/
-LIBLTE_ERROR_ENUM liblte_mme_pack_deactivate_eps_bearer_context_accept_msg(LIBLTE_MME_DEACTIVATE_EPS_BEARER_CONTEXT_ACCEPT_MSG_STRUCT *deact_eps_bearer_context_accept,
+LIBLTE_ERROR_ENUM liblte_mme_pack_deactivate_eps_bearer_context_accept_msg(
+    LIBLTE_MME_DEACTIVATE_EPS_BEARER_CONTEXT_ACCEPT_MSG_STRUCT* deact_eps_bearer_context_accept,
+    uint8                                                       sec_hdr_type,
+    uint32                                                      count,
     LIBLTE_BYTE_MSG_STRUCT*                                     msg)
 {
   LIBLTE_ERROR_ENUM err     = LIBLTE_ERROR_INVALID_INPUTS;
   uint8*            msg_ptr = msg->msg;
 
-    if(deact_eps_bearer_context_accept != NULL &&
+  if (deact_eps_bearer_context_accept != NULL && msg != NULL) {
-       msg                             != NULL)
+    if (LIBLTE_MME_SECURITY_HDR_TYPE_PLAIN_NAS != sec_hdr_type) {
-    {
+      // Protocol Discriminator and Security Header Type
+      *msg_ptr = (sec_hdr_type << 4) | (LIBLTE_MME_PD_EPS_MOBILITY_MANAGEMENT);
+      msg_ptr++;
+
+      // MAC will be filled in later
+      msg_ptr += 4;
+
+      // Sequence Number
+      *msg_ptr = count & 0xFF;
+      msg_ptr++;
+    }
+
     // Protocol Discriminator and EPS Bearer ID
     *msg_ptr = (deact_eps_bearer_context_accept->eps_bearer_id << 4) | (LIBLTE_MME_PD_EPS_SESSION_MANAGEMENT);
     msg_ptr++;
@@ -9832,8 +9846,7 @@ LIBLTE_ERROR_ENUM liblte_mme_pack_deactivate_eps_bearer_context_accept_msg(LIBLT
     msg_ptr++;
 
     // Protocol Configuration Options
-        if(deact_eps_bearer_context_accept->protocol_cnfg_opts_present)
+    if (deact_eps_bearer_context_accept->protocol_cnfg_opts_present) {
-        {
       *msg_ptr = LIBLTE_MME_PROTOCOL_CONFIGURATION_OPTIONS_IEI;
       msg_ptr++;
       liblte_mme_pack_protocol_config_options_ie(&deact_eps_bearer_context_accept->protocol_cnfg_opts, &msg_ptr);

srsue/hdr/stack/upper/nas.h

@@ -183,6 +183,7 @@ private:
   void parse_detach_request(uint32_t lcid, srslte::unique_byte_buffer_t pdu);
   void parse_emm_status(uint32_t lcid, srslte::unique_byte_buffer_t pdu);
   void parse_activate_dedicated_eps_bearer_context_request(uint32_t lcid, srslte::unique_byte_buffer_t pdu);
+  void parse_deactivate_eps_bearer_context_request(srslte::unique_byte_buffer_t pdu);
   void parse_activate_test_mode(uint32_t lcid, srslte::unique_byte_buffer_t pdu, const uint8_t sec_hdr_type);
 
   // Packet generators
@@ -202,6 +203,7 @@ private:
   void send_detach_accept();
   void send_activate_dedicated_eps_bearer_context_accept(const uint8_t& proc_transaction_id,
                                                          const uint8_t& eps_bearer_id);
+  void send_deactivate_eps_bearer_context_accept(const uint8_t& proc_transaction_id, const uint8_t& eps_bearer_id);
   void send_activate_test_mode_complete(const uint8_t sec_hdr_type);
 
   // security context persistence file

srsue/src/stack/upper/nas.cc

@@ -419,6 +419,9 @@ void nas::write_pdu(uint32_t lcid, unique_byte_buffer_t pdu)
     case LIBLTE_MME_MSG_TYPE_ACTIVATE_DEDICATED_EPS_BEARER_CONTEXT_REQUEST:
       parse_activate_dedicated_eps_bearer_context_request(lcid, std::move(pdu));
       break;
+    case LIBLTE_MME_MSG_TYPE_DEACTIVATE_EPS_BEARER_CONTEXT_REQUEST:
+      parse_deactivate_eps_bearer_context_request(std::move(pdu));
+      break;
     case LIBLTE_MME_MSG_TYPE_ACTIVATE_TEST_MODE:
       parse_activate_test_mode(lcid, std::move(pdu), sec_hdr_type);
       break;
@@ -1115,6 +1118,24 @@ void nas::parse_activate_dedicated_eps_bearer_context_request(uint32_t lcid, uni
   send_activate_dedicated_eps_bearer_context_accept(request.proc_transaction_id, request.eps_bearer_id);
 }
 
+void nas::parse_deactivate_eps_bearer_context_request(unique_byte_buffer_t pdu)
+{
+  LIBLTE_MME_DEACTIVATE_EPS_BEARER_CONTEXT_REQUEST_MSG_STRUCT request;
+
+  liblte_mme_unpack_deactivate_eps_bearer_context_request_msg((LIBLTE_BYTE_MSG_STRUCT*)pdu.get(), &request);
+
+  nas_log->info("Received Deactivate EPS bearer context request (eps_bearer_id=%d, proc_id=%d)\n",
+                request.eps_bearer_id,
+                request.proc_transaction_id);
+
+  ctxt.rx_count++;
+
+  // fixme: add proper checks before sending accepts
+
+  send_deactivate_eps_bearer_context_accept(request.proc_transaction_id, request.eps_bearer_id);
+}
+
+
 void nas::parse_activate_test_mode(uint32_t lcid, unique_byte_buffer_t pdu, const uint8_t sec_hdr_type)
 {
   nas_log->info("Received Activate test mode\n");
@@ -1785,6 +1806,46 @@ void nas::send_activate_dedicated_eps_bearer_context_accept(const uint8_t& proc_
   ctxt.tx_count++;
 }
 
+void nas::send_deactivate_eps_bearer_context_accept(const uint8_t& proc_transaction_id, const uint8_t& eps_bearer_id)
+{
+  unique_byte_buffer_t pdu = srslte::allocate_unique_buffer(*pool, true);
+
+  LIBLTE_MME_DEACTIVATE_EPS_BEARER_CONTEXT_ACCEPT_MSG_STRUCT accept = {};
+
+  accept.eps_bearer_id       = eps_bearer_id;
+  accept.proc_transaction_id = proc_transaction_id;
+
+  if (liblte_mme_pack_deactivate_eps_bearer_context_accept_msg(&accept,
+                                                               LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY_AND_CIPHERED,
+                                                               ctxt.tx_count,
+                                                               (LIBLTE_BYTE_MSG_STRUCT*)pdu.get())) {
+    nas_log->error("Error packing Aeactivate EPS Bearer context accept.\n");
+    return;
+  }
+
+  if (pcap != NULL) {
+    pcap->write_nas(pdu->msg, pdu->N_bytes);
+  }
+
+  cipher_encrypt(pdu.get());
+  if (pdu->N_bytes > 5) {
+    integrity_generate(
+        &k_nas_int[16], ctxt.tx_count, SECURITY_DIRECTION_UPLINK, &pdu->msg[5], pdu->N_bytes - 5, &pdu->msg[1]);
+  } else {
+    nas_log->error("Invalid PDU size %d\n", pdu->N_bytes);
+    return;
+  }
+
+  nas_log->info_hex(pdu->msg,
+                    pdu->N_bytes,
+                    "Sending Deactivate EPS Bearer context accept (eps_bearer_id=%d, proc_id=%d)\n",
+                    accept.eps_bearer_id,
+                    accept.proc_transaction_id);
+  rrc->write_sdu(std::move(pdu));
+
+  ctxt.tx_count++;
+}
+
 void nas::send_activate_test_mode_complete(const uint8_t sec_hdr_type)
 {
   unique_byte_buffer_t pdu = srslte::allocate_unique_buffer(*pool, true);