srsLTE/srsepc/hdr/mme/nas.h

/*
 * \section LICENSE
 *
 * This file is part of srsLTE.
 *
 * srsLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * srsLTE is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * A copy of the GNU Affero General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */
#ifndef SRSEPC_NAS_H
#define SRSEPC_NAS_H

#include "srslte/common/security.h"
#include "srslte/asn1/gtpc_ies.h"
#include "srslte/asn1/liblte_s1ap.h"
#include "srslte/asn1/liblte_mme.h"
#include <netinet/sctp.h>

namespace srsepc{

static const uint8_t MAX_ERABS_PER_UE = 16;

// MME EMM states (3GPP 24.301 v10.0.0, section 5.1.3.4)
typedef enum {
  EMM_STATE_DEREGISTERED = 0,
  EMM_STATE_COMMON_PROCEDURE_INITIATED,
  EMM_STATE_REGISTERED,
  EMM_STATE_DEREGISTERED_INITIATED,
  EMM_STATE_N_ITEMS,
} emm_state_t;
static const char emm_state_text[EMM_STATE_N_ITEMS][100] = {"DEREGISTERED",
                                                            "COMMON PROCEDURE INITIATED",
                                                            "REGISTERED",
                                                            "DEREGISTERED INITIATED"};

// MME ECM states (3GPP 23.401 v10.0.0, section 4.6.3)
typedef enum {
  ECM_STATE_IDLE = 0,
  ECM_STATE_CONNECTED,
  ECM_STATE_N_ITEMS,
} ecm_state_t;
static const char ecm_state_text[ECM_STATE_N_ITEMS][100] = {"IDLE",
                                                            "CONNECTED"};
/*
// MME ESM states (3GPP 23.401 v10.0.0, section 4.6.3)
typedef enum {
  ESM_BEARER_CONTEXT_INACTIVE = 0,
  ESM_BEARER_CONTEXT_ACTIVE_PENDING,
  ESM_BEARER_CONTEXT_ACTIVE,
  ESM_BEARER_CONTEXT_INACTIVE_PENDING,
  ESM_BEARER_CONTEXT_MODIFY_PENDING,
  ESM_BEARER_PROCEDURE_TRANSACTION_INACTIVE,
  ESM_BEARER_PROCEDURE_TRANSACTION_PENDING,
  ESM_STATE_N_ITEMS,
} esm_state_t;
static const char esm_state_text[ESM_STATE_N_ITEMS][100] = {"CONTEXT INACTIVE",
                                                            "CONTEXT ACTIVE PENDING",
                                                            "CONTEXT ACTIVE",
                                                            "CONTEXT_INACTIVE_PENDING",
                                                            "CONTEXT_MODIFY_PENDING",
                                                            "PROCEDURE_TRANSACTION_INACTIVE"
                                                            "PROCEDURE_TRANSACTION_PENDING"};
*/
typedef enum
{
  ERAB_DEACTIVATED,
  ERAB_CTX_REQUESTED,
  ERAB_CTX_SETUP,
  ERAB_ACTIVE
} esm_state_t;

/*
 * EMM, ECM, ESM and EPS Security context definition
 */
typedef struct{
    uint64_t    imsi;
    emm_state_t state;
    uint8_t     procedure_transaction_id;
    uint8_t     attach_type;
    struct in_addr ue_ip;
    srslte::gtpc_f_teid_ie sgw_ctrl_fteid;
} emm_ctx_t;

typedef struct{
  ecm_state_t state;
  uint32_t enb_ue_s1ap_id;
  uint32_t mme_ue_s1ap_id;
  struct   sctp_sndrcvinfo enb_sri;
  bool eit;
} ecm_ctx_t;

typedef struct{
  uint8_t erab_id;
  esm_state_t state;
  uint8_t qci;
  srslte::gtpc_f_teid_ie enb_fteid;
  srslte::gtpc_f_teid_ie sgw_s1u_fteid;
  srslte::gtpc_pdn_address_allocation_ie pdn_addr_alloc;
} esm_ctx_t;

typedef struct{
  uint8_t  eksi;
  uint8_t  k_asme[32];
  uint8_t  xres[16]; //minimum 6, maximum 16
  uint32_t dl_nas_count;
  uint32_t ul_nas_count;
  srslte::CIPHERING_ALGORITHM_ID_ENUM cipher_algo;
  srslte::INTEGRITY_ALGORITHM_ID_ENUM integ_algo;
  uint8_t k_nas_enc[32];
  uint8_t k_nas_int[32];
  uint8_t k_enb[32];
  LIBLTE_MME_UE_NETWORK_CAPABILITY_STRUCT ue_network_cap;
  bool ms_network_cap_present;
  LIBLTE_MME_MS_NETWORK_CAPABILITY_STRUCT ms_network_cap;
  LIBLTE_MME_EPS_MOBILE_ID_GUTI_STRUCT guti;
} sec_ctx_t;

class nas
{
public:
  /*Initial UE messages*/
  bool handle_nas_attach_request(      uint32_t enb_ue_s1ap_id,
                                       srslte::byte_buffer_t *nas_msg,
                                       srslte::byte_buffer_t *reply_buffer,
                                       bool* reply_flag,
                                       struct sctp_sndrcvinfo *enb_sri);

  bool handle_nas_imsi_attach_request( uint32_t enb_ue_s1ap_id,
                                       const LIBLTE_MME_ATTACH_REQUEST_MSG_STRUCT &attach_req,
                                       const LIBLTE_MME_PDN_CONNECTIVITY_REQUEST_MSG_STRUCT &pdn_con_req,
                                       srslte::byte_buffer_t *reply_buffer,
                                       bool* reply_flag,
                                       struct sctp_sndrcvinfo *enb_sri);

  bool handle_nas_guti_attach_request( uint32_t enb_ue_s1ap_id,
                                       const LIBLTE_MME_ATTACH_REQUEST_MSG_STRUCT &attach_req,
                                       const LIBLTE_MME_PDN_CONNECTIVITY_REQUEST_MSG_STRUCT &pdn_con_req,
                                       srslte::byte_buffer_t *nas_msg,
                                       srslte::byte_buffer_t *reply_buffer,
                                       bool* reply_flag,
                                       struct sctp_sndrcvinfo *enb_sri);

  bool handle_nas_service_request(     uint32_t m_tmsi,
                                       uint32_t enb_ue_s1ap_id,
                                       srslte::byte_buffer_t *nas_msg,
                                       srslte::byte_buffer_t *reply_buffer,
                                       bool* reply_flag,
                                       struct sctp_sndrcvinfo *enb_sri);

  bool handle_nas_detach_request(      uint32_t m_tmsi,
                                       uint32_t enb_ue_s1ap_id,
                                       srslte::byte_buffer_t *nas_msg,
                                       srslte::byte_buffer_t *reply_buffer,
                                       bool* reply_flag,
                                       struct sctp_sndrcvinfo *enb_sri);

  bool handle_nas_tracking_area_update_request( uint32_t m_tmsi,
                                                uint32_t enb_ue_s1ap_id,
                                                srslte::byte_buffer_t *nas_msg,
                                                srslte::byte_buffer_t *reply_buffer,
                                                bool* reply_flag,
                                                struct sctp_sndrcvinfo *enb_sri);

  /* Uplink NAS messages handling */
  bool handle_nas_authentication_response(  srslte::byte_buffer_t *nas_msg, srslte::byte_buffer_t *reply_buffer, bool* reply_flag);
  bool handle_nas_security_mode_complete(   srslte::byte_buffer_t *nas_msg, srslte::byte_buffer_t *reply_buffer, bool *reply_flag);
  bool handle_nas_attach_complete(          srslte::byte_buffer_t *nas_msg, srslte::byte_buffer_t *reply_buffer, bool *reply_flag);
  bool handle_esm_information_response(     srslte::byte_buffer_t *nas_msg, srslte::byte_buffer_t *reply_buffer, bool *reply_flag);
  bool handle_identity_response(            srslte::byte_buffer_t *nas_msg, srslte::byte_buffer_t *reply_buffer, bool *reply_flag);
  bool handle_tracking_area_update_request( srslte::byte_buffer_t *nas_msg, srslte::byte_buffer_t *reply_buffer, bool *reply_flag);
  bool handle_authentication_failure(       srslte::byte_buffer_t *nas_msg, srslte::byte_buffer_t *reply_buffer, bool *reply_flag);
  bool handle_nas_detach_request(           srslte::byte_buffer_t *nas_msg, srslte::byte_buffer_t *reply_buffer, bool *reply_flag);

  /* Downlink NAS messages packing*/
  bool pack_authentication_request  (srslte::byte_buffer_t *reply_msg);
  bool pack_authentication_reject   (srslte::byte_buffer_t *reply_msg, uint32_t enb_ue_s1ap_id, uint32_t mme_ue_s1ap_id);
  bool pack_security_mode_command   (srslte::byte_buffer_t *reply_msg, emm_ctx_t *ue_emm_ctx, ecm_ctx_t *ue_ecm_ctx);
  bool pack_esm_information_request (srslte::byte_buffer_t *reply_msg, emm_ctx_t *ue_emm_ctx, ecm_ctx_t *ue_ecm_ctx);
  bool pack_identity_request        (srslte::byte_buffer_t *reply_msg);
  bool pack_emm_information         (srslte::byte_buffer_t *reply_msg);
  bool pack_service_reject          (srslte::byte_buffer_t *reply_msg);
  bool pack_attach_accept           (emm_ctx_t *ue_emm_ctx, ecm_ctx_t *ue_ecm_ctx, LIBLTE_S1AP_E_RABTOBESETUPITEMCTXTSUREQ_STRUCT *erab_ctxt, struct srslte::gtpc_pdn_address_allocation_ie *paa, srslte::byte_buffer_t *nas_buffer);

  /* Security functions */
  bool integrity_check       (srslte::byte_buffer_t *pdu);
  bool short_integrity_check (srslte::byte_buffer_t *pdu);

  /* UE Context*/
  emm_ctx_t m_emm_ctx;
  ecm_ctx_t m_ecm_ctx;
  esm_ctx_t m_esm_ctx[MAX_ERABS_PER_UE];
  sec_ctx_t m_sec_ctx;
};

}//namespace
#endif // SRSEPC_S1AP_COMMON_H