open5gs/src/mme/emm-sm.c

#include "nas/nas-message.h"
#include "fd/fd-lib.h"
#include "fd/s6a/s6a-message.h"

#include "mme-event.h"
#include "mme-kdf.h"
#include "s1ap-handler.h"
#include "mme-fd-path.h"
#include "emm-handler.h"
#include "emm-build.h"
#include "esm-handler.h"
#include "nas-path.h"
#include "s1ap-path.h"
#include "mme-gtp-path.h"
#include "mme-path.h"
#include "mme-sm.h"

#undef OGS_LOG_DOMAIN
#define OGS_LOG_DOMAIN __emm_log_domain

void emm_state_initial(ogs_fsm_t *s, mme_event_t *e)
{
    ogs_assert(s);

    mme_sm_debug(e);

    OGS_FSM_TRAN(s, &emm_state_de_registered);
}

void emm_state_final(ogs_fsm_t *s, mme_event_t *e)
{
    ogs_assert(s);

    mme_sm_debug(e);
}

static void common_register_state(ogs_fsm_t *s, mme_event_t *e);

void emm_state_de_registered(ogs_fsm_t *s, mme_event_t *e)
{
    ogs_assert(s);
    ogs_assert(e);

    mme_sm_debug(e);

    common_register_state(s, e);
}

void emm_state_registered(ogs_fsm_t *s, mme_event_t *e)
{
    ogs_assert(s);
    ogs_assert(e);

    mme_sm_debug(e);

    common_register_state(s, e);
}

static void common_register_state(ogs_fsm_t *s, mme_event_t *e)
{
    int rv;

    mme_ue_t *mme_ue = NULL;
    enb_ue_t *enb_ue = NULL;
    
    ogs_assert(e);
        
    mme_ue = e->mme_ue;
    ogs_assert(mme_ue);

    switch (e->id)
    {
        case OGS_FSM_ENTRY_SIG:
        {
            return;
        }
        case OGS_FSM_EXIT_SIG:
        {
            return;
        }
        case MME_EVT_EMM_MESSAGE:
        {
            nas_message_t *message = e->nas_message;
            ogs_assert(message);

            enb_ue = mme_ue->enb_ue;
            ogs_assert(enb_ue);

            if (message->emm.h.security_header_type
                    == NAS_SECURITY_HEADER_FOR_SERVICE_REQUEST_MESSAGE)
            {
                ogs_debug("[EMM] Service request");
                rv = emm_handle_service_request(
                        mme_ue, &message->emm.service_request);
                if (rv != OGS_OK)
                {
                    ogs_error("emm_handle_service_request() failed");
                    OGS_FSM_TRAN(s, emm_state_exception);
                    return;
                }

                if (!MME_UE_HAVE_IMSI(mme_ue))
                {
                    ogs_warn("[EMM] Service request : Unknown UE");
                    rv = nas_send_service_reject(mme_ue,
                        EMM_CAUSE_UE_IDENTITY_CANNOT_BE_DERIVED_BY_THE_NETWORK);
                    ogs_assert(rv == OGS_OK);
                    OGS_FSM_TRAN(s, &emm_state_exception);
                    return;
                }

                if (!SECURITY_CONTEXT_IS_VALID(mme_ue))
                {
                    ogs_warn("No Security Context : IMSI[%s]", mme_ue->imsi_bcd);
                    rv = nas_send_service_reject(mme_ue,
                        EMM_CAUSE_UE_IDENTITY_CANNOT_BE_DERIVED_BY_THE_NETWORK);
                    ogs_assert(rv == OGS_OK);

                    rv = s1ap_send_ue_context_release_command(enb_ue, 
                        S1AP_Cause_PR_nas, S1AP_CauseNas_normal_release,
                        S1AP_UE_CTX_REL_S1_NORMAL_RELEASE, 0);
                    ogs_assert(rv == OGS_OK);
                    return;
                }

                rv = s1ap_send_initial_context_setup_request(mme_ue);
                ogs_assert(rv == OGS_OK);
                return;
            }

            switch(message->emm.h.message_type)
            {
                case NAS_IDENTITY_RESPONSE:
                {
                    ogs_debug("[EMM] Identity response");
                    rv = emm_handle_identity_response(mme_ue,
                            &message->emm.identity_response);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_identity_response() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    if (!MME_UE_HAVE_IMSI(mme_ue))
                    {
                        ogs_error("No IMSI");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
                    break;
                }
                case NAS_ATTACH_REQUEST:
                {
                    ogs_debug("[EMM] Attach request[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_attach_request(
                            mme_ue, &message->emm.attach_request);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }
                    break;
                }
                case NAS_TRACKING_AREA_UPDATE_REQUEST:
                {
                    ogs_debug("[EMM] Tracking area update request");
                    rv = emm_handle_tau_request(
                            mme_ue, &message->emm.tracking_area_update_request);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_tau_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    if (!MME_UE_HAVE_IMSI(mme_ue))
                    {
                        ogs_warn("[EMM] TAU request : Unknown UE");
                        rv = nas_send_tau_reject(mme_ue,
                        EMM_CAUSE_UE_IDENTITY_CANNOT_BE_DERIVED_BY_THE_NETWORK);
                        ogs_assert(rv == OGS_OK);
                        OGS_FSM_TRAN(s, &emm_state_exception);
                        return;
                    }

                    break;
                }
                case NAS_TRACKING_AREA_UPDATE_COMPLETE:
                {
                    ogs_debug("[EMM] Tracking area update complete");
                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
                    return;
                }
                case NAS_EMM_STATUS:
                {
                    ogs_warn("[EMM] EMM STATUS : IMSI[%s] Cause[%d]",
                            mme_ue->imsi_bcd,
                            message->emm.emm_status.emm_cause);
                    OGS_FSM_TRAN(s, &emm_state_exception);
                    return;
                }
                case NAS_DETACH_REQUEST:
                {
                    ogs_debug("[EMM] Detach request");
                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_detach_request(
                            mme_ue, &message->emm.detach_request_from_ue);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    rv = mme_send_delete_session_or_detach(mme_ue);
                    ogs_assert(rv == OGS_OK);

                    OGS_FSM_TRAN(s, &emm_state_de_registered);
                    return;
                }
                default:
                {
                    ogs_warn("Unknown message[%d]", message->emm.h.message_type);
                    return;
                }
            }
            break;
        }
        default:
        {
            ogs_error("Unknown event[%s]", mme_event_get_name(e));
            return;
        }
    }

    if (!MME_UE_HAVE_IMSI(mme_ue))
    {
        rv = nas_send_identity_request(mme_ue);
        ogs_assert(rv == OGS_OK);
        return;
    }

    enb_ue = mme_ue->enb_ue;
    ogs_assert(enb_ue);

    switch(mme_ue->nas_eps.type)
    {
        case MME_EPS_TYPE_ATTACH_REQUEST:
        {
            if (SECURITY_CONTEXT_IS_VALID(mme_ue))
            {
                rv = nas_send_emm_to_esm(mme_ue,
                        &mme_ue->pdn_connectivity_request);
                ogs_assert(rv == OGS_OK);
                OGS_FSM_TRAN(s, &emm_state_initial_context_setup);
            }
            else
            {
                if (SESSION_CONTEXT_IS_AVAILABLE(mme_ue))
                {
                    rv = mme_gtp_send_delete_all_sessions(mme_ue);
                    ogs_assert(rv == OGS_OK);
                }
                else
                {
                    mme_s6a_send_air(mme_ue, NULL);
                }
                OGS_FSM_TRAN(s, &emm_state_authentication);
            }
            break;
        }
        case MME_EPS_TYPE_TAU_REQUEST:
        {
            S1AP_ProcedureCode_t procedureCode = e->s1ap_code;

            if (!SESSION_CONTEXT_IS_AVAILABLE(mme_ue))
            {
                ogs_warn("No PDN Connection : UE[%s]", mme_ue->imsi_bcd);
                rv = nas_send_tau_reject(mme_ue,
                    EMM_CAUSE_UE_IDENTITY_CANNOT_BE_DERIVED_BY_THE_NETWORK);
                ogs_assert(rv == OGS_OK);
                OGS_FSM_TRAN(s, emm_state_exception);
                break;
            }

            if (!SECURITY_CONTEXT_IS_VALID(mme_ue))
            {
                mme_s6a_send_air(mme_ue, NULL);
                OGS_FSM_TRAN(&mme_ue->sm, &emm_state_authentication);
                break;
            }

            if (procedureCode == S1AP_ProcedureCode_id_initialUEMessage)
            {
                ogs_debug("    Iniital UE Message");
                if (mme_ue->nas_eps.update.active_flag)
                {
                    rv = nas_send_tau_accept(mme_ue,
                            S1AP_ProcedureCode_id_InitialContextSetup);
                    ogs_assert(rv == OGS_OK);
                }
                else
                {
                    rv = nas_send_tau_accept(mme_ue,
                            S1AP_ProcedureCode_id_downlinkNASTransport);
                    ogs_assert(rv == OGS_OK);

                    rv = mme_send_release_access_bearer_or_ue_context_release(
                            mme_ue, enb_ue);
                    ogs_assert(rv == OGS_OK);
                }
            }
            else if (procedureCode == S1AP_ProcedureCode_id_uplinkNASTransport)
            {
                ogs_debug("    Uplink NAS Transport");
                rv = nas_send_tau_accept(mme_ue,
                        S1AP_ProcedureCode_id_downlinkNASTransport);
                ogs_assert(rv == OGS_OK);
            }
            else
            {
                ogs_fatal("Invalid Procedure Code[%d]", (int)procedureCode);
                ogs_assert_if_reached();
            }
            break;
        }
        default:
            ogs_fatal("Invalid NAS-EPS[%d]", mme_ue->nas_eps.type);
            ogs_assert_if_reached();
            break;
    }
}

void emm_state_authentication(ogs_fsm_t *s, mme_event_t *e)
{
    int rv;
    mme_ue_t *mme_ue = NULL;

    ogs_assert(s);
    ogs_assert(e);
    
    mme_sm_debug(e);

    mme_ue = e->mme_ue;
    ogs_assert(mme_ue);

    switch (e->id)
    {
        case OGS_FSM_ENTRY_SIG:
        {
            break;
        }
        case OGS_FSM_EXIT_SIG:
        {
            break;
        }
        case MME_EVT_EMM_MESSAGE:
        {
            nas_message_t *message = e->nas_message;
            ogs_assert(message);

            switch(message->emm.h.message_type)
            {
                case NAS_AUTHENTICATION_RESPONSE:
                {
                    nas_authentication_response_t *authentication_response =
                        &message->emm.authentication_response;
                    nas_authentication_response_parameter_t
                        *authentication_response_parameter =
                            &authentication_response->
                                authentication_response_parameter;

                    ogs_debug("[EMM] Authentication response");
                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);

                    if (memcmp(authentication_response_parameter->res,
                        mme_ue->xres,
                        authentication_response_parameter->length) != 0)
                    {
                        ogs_log_hexdump(OGS_LOG_WARN,
                                authentication_response_parameter->res,
                                authentication_response_parameter->length);
                        ogs_log_hexdump(OGS_LOG_WARN,
                                mme_ue->xres, MAX_RES_LEN);
                        rv = nas_send_authentication_reject(mme_ue);
                        ogs_assert(rv == OGS_OK);
                        OGS_FSM_TRAN(&mme_ue->sm, &emm_state_exception);
                    }
                    else
                    {
                        OGS_FSM_TRAN(&mme_ue->sm, &emm_state_security_mode);
                    }
                    break;
                }
                case NAS_AUTHENTICATION_FAILURE:
                {
                    nas_authentication_failure_t *authentication_failure =
                        &message->emm.authentication_failure;
                    nas_authentication_failure_parameter_t
                        *authentication_failure_parameter = 
                            &authentication_failure->
                                authentication_failure_parameter;

                    ogs_debug("[EMM] Authentication failure");
                    ogs_debug("    IMSI[%s] EMM_CAUSE[%d]", mme_ue->imsi_bcd,
                            authentication_failure->emm_cause);

                    switch(authentication_failure->emm_cause)
                    {
                        case EMM_CAUSE_MAC_FAILURE:
                            ogs_warn("Authentication failure(MAC failure)");
                            break;
                        case EMM_CAUSE_NON_EPS_AUTHENTICATION_UNACCEPTABLE:
                            ogs_error("Authentication failure"
                                    "(Non-EPS authentication unacceptable)");
                            break;
                        case EMM_CAUSE_SYNCH_FAILURE:
                            ogs_warn("Authentication failure(Synch failure)");
                            mme_s6a_send_air(mme_ue,
                                    authentication_failure_parameter);
                            return;
                        default:
                            ogs_error("Unknown EMM_CAUSE{%d] in Authentication"
                                    " failure",
                                    authentication_failure->emm_cause);
                            break;
                    }

                    rv = nas_send_authentication_reject(mme_ue);
                    ogs_assert(rv == OGS_OK);
                    OGS_FSM_TRAN(&mme_ue->sm, &emm_state_exception);
                    break;
                }
                case NAS_ATTACH_REQUEST:
                {
                    ogs_warn("[EMM] Attach request[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_attach_request(
                            mme_ue, &message->emm.attach_request);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    mme_s6a_send_air(mme_ue, NULL);
                    OGS_FSM_TRAN(s, &emm_state_authentication);
                    break;
                }
                case NAS_EMM_STATUS:
                {
                    ogs_warn("[EMM] EMM STATUS : IMSI[%s] Cause[%d]",
                            mme_ue->imsi_bcd,
                            message->emm.emm_status.emm_cause);
                    OGS_FSM_TRAN(s, &emm_state_exception);
                    break;
                }
                case NAS_DETACH_REQUEST:
                {
                    ogs_debug("[EMM] Detach request");
                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_detach_request(
                            mme_ue, &message->emm.detach_request_from_ue);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    rv = mme_send_delete_session_or_detach(mme_ue);
                    ogs_assert(rv == OGS_OK);

                    OGS_FSM_TRAN(s, &emm_state_de_registered);
                    break;
                }
                default:
                {
                    ogs_warn("Unknown message[%d]", message->emm.h.message_type);
                    break;
                }
            }
            break;
        }
        default:
        {
            ogs_error("Unknown event[%s]", mme_event_get_name(e));
            break;
        }
    }
}

void emm_state_security_mode(ogs_fsm_t *s, mme_event_t *e)
{
    int rv;
    mme_ue_t *mme_ue = NULL;

    ogs_assert(s);
    ogs_assert(e);

    mme_sm_debug(e);

    mme_ue = e->mme_ue;
    ogs_assert(mme_ue);

    switch (e->id)
    {
        case OGS_FSM_ENTRY_SIG:
        {
            ogs_pkbuf_t *emmbuf = NULL;

            rv = emm_build_security_mode_command(&emmbuf, mme_ue);
            ogs_assert(rv == OGS_OK && emmbuf);

            rv = nas_send_to_downlink_nas_transport(mme_ue, emmbuf);
            ogs_assert(rv == OGS_OK && emmbuf);

            break;
        }
        case OGS_FSM_EXIT_SIG:
        {
            break;
        }
        case MME_EVT_EMM_MESSAGE:
        {
            nas_message_t *message = e->nas_message;
            ogs_assert(message);

            switch(message->emm.h.message_type)
            {
                case NAS_SECURITY_MODE_COMPLETE:
                {
                    ogs_debug("[EMM] Security mode complete");
                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);

                    /* Update Kenb */
                    if (SECURITY_CONTEXT_IS_VALID(mme_ue))
                    {
                        mme_kdf_enb(mme_ue->kasme, mme_ue->ul_count.i32, 
                                mme_ue->kenb);
                        mme_kdf_nh(mme_ue->kasme, mme_ue->kenb, mme_ue->nh);
                        mme_ue->nhcc = 1;
                    }

                    mme_s6a_send_ulr(mme_ue);
                    if (mme_ue->nas_eps.type == MME_EPS_TYPE_ATTACH_REQUEST)
                    {
                        OGS_FSM_TRAN(s, &emm_state_initial_context_setup);
                    }
                    else if (mme_ue->nas_eps.type ==
                            MME_EPS_TYPE_SERVICE_REQUEST ||
                            mme_ue->nas_eps.type == MME_EPS_TYPE_TAU_REQUEST)
                    {
                        OGS_FSM_TRAN(s, &emm_state_registered);
                    }
                    else
                    {
                        ogs_fatal("Invalid NAS_EPS[%d]", mme_ue->nas_eps.type);
                        ogs_assert_if_reached();
                    }
                    break;
                }
                case NAS_SECURITY_MODE_REJECT:
                {
                    ogs_warn("[EMM] Security mode reject : IMSI[%s] Cause[%d]",
                            mme_ue->imsi_bcd,
                            message->emm.security_mode_reject.emm_cause);
                    OGS_FSM_TRAN(s, &emm_state_exception);
                    break;
                }
                case NAS_ATTACH_REQUEST:
                {
                    ogs_warn("[EMM] Attach request[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_attach_request(
                            mme_ue, &message->emm.attach_request);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    mme_s6a_send_air(mme_ue, NULL);
                    OGS_FSM_TRAN(s, &emm_state_authentication);
                    break;
                }
                case NAS_EMM_STATUS:
                {
                    ogs_warn("[EMM] EMM STATUS : IMSI[%s] Cause[%d]",
                            mme_ue->imsi_bcd,
                            message->emm.emm_status.emm_cause);
                    OGS_FSM_TRAN(s, &emm_state_exception);
                    break;
                }
                case NAS_DETACH_REQUEST:
                {
                    ogs_debug("[EMM] Detach request");
                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_detach_request(
                            mme_ue, &message->emm.detach_request_from_ue);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    rv = mme_send_delete_session_or_detach(mme_ue);
                    ogs_assert(rv == OGS_OK);

                    OGS_FSM_TRAN(s, &emm_state_de_registered);
                    break;
                }
                default:
                {
                    ogs_warn("Unknown message[%d]", message->emm.h.message_type);
                    break;
                }
            }
            break;
        }
        default:
        {
            ogs_error("Unknown event[%s]", mme_event_get_name(e));
            break;
        }
    }
}

void emm_state_initial_context_setup(ogs_fsm_t *s, mme_event_t *e)
{
    int rv;
    mme_ue_t *mme_ue = NULL;

    ogs_assert(s);
    ogs_assert(e);

    mme_sm_debug(e);

    mme_ue = e->mme_ue;
    ogs_assert(mme_ue);

    switch (e->id)
    {
        case OGS_FSM_ENTRY_SIG:
        {
            break;
        }
        case OGS_FSM_EXIT_SIG:
        {
            break;
        }
        case MME_EVT_EMM_MESSAGE:
        {
            nas_message_t *message = e->nas_message;
            ogs_assert(message);

            switch(message->emm.h.message_type)
            {
                case NAS_ATTACH_COMPLETE:
                {
                    ogs_debug("[EMM] Attach complete");
                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_attach_complete(
                            mme_ue, &message->emm.attach_complete);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_complete() failed "
                                "in emm_state_initial_context_setup");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        break;
                    }
                    OGS_FSM_TRAN(s, &emm_state_registered);
                    break;
                }
                case NAS_ATTACH_REQUEST:
                {
                    ogs_warn("[EMM] Attach request[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_attach_request(
                            mme_ue, &message->emm.attach_request);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    rv = mme_gtp_send_delete_all_sessions(mme_ue);
                    ogs_assert(rv == OGS_OK);
                    OGS_FSM_TRAN(s, &emm_state_authentication);
                    break;
                }
                case NAS_EMM_STATUS:
                {
                    ogs_warn("[EMM] EMM STATUS : IMSI[%s] Cause[%d]",
                            mme_ue->imsi_bcd,
                            message->emm.emm_status.emm_cause);
                    OGS_FSM_TRAN(s, &emm_state_exception);
                    break;
                }
                case NAS_DETACH_REQUEST:
                {
                    ogs_debug("[EMM] Detach request");
                    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
                    rv = emm_handle_detach_request(
                            mme_ue, &message->emm.detach_request_from_ue);
                    if (rv != OGS_OK)
                    {
                        ogs_error("emm_handle_attach_request() failed");
                        OGS_FSM_TRAN(s, emm_state_exception);
                        return;
                    }

                    rv = mme_send_delete_session_or_detach(mme_ue);
                    ogs_assert(rv == OGS_OK);

                    OGS_FSM_TRAN(s, &emm_state_de_registered);
                    break;
                }
                default:
                {
                    ogs_warn("Unknown message[%d]", 
                            message->emm.h.message_type);
                    break;
                }
            }
            break;
        }
        default:
        {
            ogs_error("Unknown event[%s]", mme_event_get_name(e));
            break;
        }
    }
}

void emm_state_exception(ogs_fsm_t *s, mme_event_t *e)
{
    ogs_assert(e);
    mme_sm_debug(e);

    switch (e->id)
    {
        case OGS_FSM_ENTRY_SIG:
        {
            break;
        }
        case OGS_FSM_EXIT_SIG:
        {
            break;
        }
        default:
        {
            ogs_error("Unknown event[%s]", mme_event_get_name(e));
            break;
        }
    }
}