[CSFB] Implement SGsAP UE-UNREACHABLE message

src/mme/emm-sm.c

@@ -293,6 +293,13 @@ static void common_register_state(ogs_fsm_t *s, mme_event_t *e)
                         mme_ue->imsi_bcd);
                 CLEAR_MME_UE_TIMER(mme_ue->t3413);
 
+                if (CS_CALL_SERVICE_INDICATOR(mme_ue) ||
+                    SMS_SERVICE_INDICATOR(mme_ue)) {
+                    sgsap_send_ue_unreachable(mme_ue,
+                            SGSAP_SGS_CAUSE_UE_UNREACHABLE);
+                }
+    
+                CLEAR_SERVICE_INDICATOR(mme_ue);
             } else {
                 mme_ue->t3413.retry_count++;
                 /*

src/mme/mme-context.h

@@ -442,8 +442,6 @@ struct mme_ue_s {
         ogs_assert((__mME)); \
         (__mME)->service_indicator = 0; \
     } while(0);
-#define SGSAP_CS_CALL_SERVICE_INDICATOR     1
-#define SGSAP_SMS_SERVICE_INDICATOR         2
 
 #define CS_CALL_SERVICE_INDICATOR(__mME) \
     (MME_P_TMSI_IS_AVAILABLE(__mME) && \

src/mme/s1ap-sm.c

@@ -198,7 +198,6 @@ void s1ap_state_operational(ogs_fsm_t *s, mme_event_t *e)
             ogs_assert(e->enb_ue);
             if (e->enb_ue->t_ue_context_release.retry_count >=
                     mme_timer_cfg(MME_TIMER_UE_CONTEXT_RELEASE)->max_count) {
-                /* Paging failed */
                 ogs_warn("[S1AP] UE Context Release failed. Stop Releasing");
                 CLEAR_ENB_UE_TIMER(e->enb_ue->t_ue_context_release);
 

src/mme/sgsap-build.c

@@ -307,3 +307,31 @@ ogs_pkbuf_t *sgsap_build_uplink_unidata(
 
     return pkbuf;
 }
+
+ogs_pkbuf_t *sgsap_build_ue_unreachable(mme_ue_t *mme_ue, uint8_t sgs_cause)
+{
+    mme_vlr_t *vlr = NULL;
+    ogs_tlv_t *root = NULL;
+    ogs_pkbuf_t *pkbuf = NULL;
+
+    ogs_assert(mme_ue);
+    vlr = mme_ue->vlr;
+    ogs_assert(vlr);
+
+    root = ogs_tlv_add(NULL, SGSAP_IE_IMSI_TYPE, SGSAP_IE_IMSI_LEN, 0,
+            &mme_ue->nas_mobile_identity_imsi);
+
+    ogs_tlv_add(root, SGSAP_IE_SGS_CAUSE_TYPE,
+            SGSAP_IE_SGS_CAUSE_LEN, 0, &sgs_cause);
+
+    pkbuf = ogs_pkbuf_alloc(NULL, MAX_SDU_LEN);
+    ogs_pkbuf_put_u8(pkbuf, SGSAP_UE_UNREACHABLE);
+    ogs_pkbuf_put(pkbuf, MAX_SDU_LEN-1);
+
+    ogs_pkbuf_trim(pkbuf, 1+ogs_tlv_render(root,
+            pkbuf->data+1, MAX_SDU_LEN-1, OGS_TLV_MODE_T1_L1));
+
+    ogs_tlv_free_all(root);
+
+    return pkbuf;
+}

src/mme/sgsap-build.h

@@ -37,6 +37,7 @@ ogs_pkbuf_t *sgsap_build_service_request(mme_ue_t *mme_ue, uint8_t emm_mode);
 ogs_pkbuf_t *sgsap_build_reset_ack(mme_vlr_t *vlr);
 ogs_pkbuf_t *sgsap_build_uplink_unidata(
         mme_ue_t *mme_ue, nas_message_container_t *nas_message_container);
+ogs_pkbuf_t *sgsap_build_ue_unreachable(mme_ue_t *mme_ue, uint8_t sgs_cause);
 
 #ifdef __cplusplus
 }

src/mme/sgsap-path.c

@@ -230,3 +230,20 @@ int sgsap_send_uplink_unitdata(
 
     return OGS_OK;
 }
+
+int sgsap_send_ue_unreachable(mme_ue_t *mme_ue, uint8_t sgs_cause)
+{
+    int rv;
+    ogs_pkbuf_t *pkbuf = NULL;
+    ogs_assert(mme_ue);
+
+    ogs_debug("[SGSAP] UE-UNREACHABLE");
+    ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
+    ogs_debug("    CAUSE[%d]", sgs_cause);
+
+    pkbuf = sgsap_build_ue_unreachable(mme_ue, sgs_cause);
+    rv = sgsap_send_to_vlr(mme_ue, pkbuf);
+    ogs_assert(rv == OGS_OK);
+
+    return OGS_OK;
+}

src/mme/sgsap-path.h

@@ -50,6 +50,7 @@ int sgsap_send_service_request(mme_ue_t *mme_ue, uint8_t emm_mode);
 int sgsap_send_reset_ack(mme_vlr_t *vlr);
 int sgsap_send_uplink_unitdata(
         mme_ue_t *mme_ue, nas_message_container_t *nas_message_container);
+int sgsap_send_ue_unreachable(mme_ue_t *mme_ue, uint8_t sgs_cause);
 
 #ifdef __cplusplus
 }

src/mme/sgsap-types.h

@@ -41,6 +41,7 @@ extern "C" {
 #define SGSAP_RESET_ACK                                             22
 #define SGSAP_MO_CSFB_INDICIATION                                   24
 #define SGSAP_RELEASE_REQUEST                                       27
+#define SGSAP_UE_UNREACHABLE                                        31
 
 #define SGSAP_IE_IMSI_TYPE                                          1
 #define SGSAP_IE_IMSI_LEN                                           MAX_IMSI_LEN
@@ -75,6 +76,9 @@ extern "C" {
 #define SGSAP_EPS_UPDATE_IMSI_ATTACH                                1
 #define SGSAP_EPS_UPDATE_NORMAL                                     2
 
+#define SGSAP_CS_CALL_SERVICE_INDICATOR                             1
+#define SGSAP_SMS_SERVICE_INDICATOR                                 2
+
 #define SGSAP_EPS_DETACH_NETWORK_INITIATED                          1
 #define SGSAP_EPS_DETACH_UE_INITIATED                               2
 #define SGSAP_EPS_DETACH_EPS_SERVICE_NOT_ALLOWED                    3