/* (C) 2018-2019 by sysmocom s.f.m.c. GmbH * All Rights Reserved * * Author: Harald Welte, Philipp Maier * * This program 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. * * This program 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. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see . * */ #include #include #include #include #include #include #include #include "vlr_sgs_fsm.h" #include "vlr_core.h" #define S(x) (1 << (x)) static const struct value_string sgs_ue_fsm_event_names[] = { {SGS_UE_E_VLR_FAILURE, "VLR_FAILURE"}, {SGS_UE_E_RX_RESET_FROM_MME, "RX_RESET_FROM_MME"}, {SGS_UE_E_RX_DETACH_IND_FROM_MME, "RX_DETACH_IND_FROM_MME"}, {SGS_UE_E_RX_DETACH_IND_FROM_UE, "RX_DETACH_IND_FROM_UE"}, /* vlr.c */ {SGS_UE_E_RX_LU_FROM_A_IU_GS, "RX_LU_FROM_A_Iu_Gs"}, /* vlr_lu_fsm.c */ {SGS_UE_E_RX_PAGING_FAILURE, "RX_PAGING_FAILURE"}, {SGS_UE_E_RX_ALERT_FAILURE, "RX_ALERT_FAILURE"}, {SGS_UE_E_RX_LU_FROM_MME, "RX_LU_FROM_MME"}, {SGS_UE_E_TX_LU_REJECT, "TX_LU_REJECT"}, {SGS_UE_E_TX_LU_ACCEPT, "TX_LU_ACCEPT"}, {SGS_UE_E_TX_PAGING, "TX_PAGING"}, {SGS_UE_E_RX_SGSAP_UE_UNREACHABLE, "RX_SGSAP_UE_UNREACH"}, {SGS_UE_E_RX_TMSI_REALLOC, "RX_TMSI_REALLOC"}, {0, NULL} }; /* Send the SGs Association to NULL state immediately */ static void to_null(struct osmo_fsm_inst *fi) { struct vlr_subscr *vsub = fi->priv; osmo_fsm_inst_state_chg(fi, SGS_UE_ST_NULL, 0, 0); /* Note: This is only relevant for cases where we are in the middle * of an TMSI reallocation procedure. Should a failure of some sort * put us to NULL state, we have to free the pending TMSI */ vsub->tmsi_new = GSM_RESERVED_TMSI; /* Make sure we remove recorded Last EUTRAN PLMN Id when UE ceases to be * available over SGs */ vlr_subscr_set_last_used_eutran_plmn_id(vsub, NULL); /* Make sure any ongoing paging is aborted. */ if (vsub->cs.is_paging) paging_expired(vsub); /* Ensure that Ts5 (pending paging via SGs) is deleted */ if (vlr_sgs_pag_pend(vsub)) osmo_timer_del(&vsub->sgs.Ts5); } /* Initiate location update and change to SGS_UE_ST_LA_UPD_PRES state */ static void perform_lu(struct osmo_fsm_inst *fi) { struct vlr_subscr *vsub = fi->priv; struct sgs_lu_response sgs_lu_response = {0}; int rc; /* Note: At the moment we allocate a new TMSI on each LU. */ rc = vlr_subscr_alloc_tmsi(vsub); if (rc != 0) { LOGPFSML(fi, LOGL_ERROR, "(sub %s) VLR LU tmsi allocation failed\n", vlr_subscr_name(vsub)); goto error; } rc = vlr_subscr_req_lu(vsub); if (rc != 0) { LOGPFSML(fi, LOGL_ERROR, "(sub %s) HLR LU request failed\n", vlr_subscr_name(vsub)); goto error; } osmo_fsm_inst_state_chg(fi, SGS_UE_ST_LA_UPD_PRES, 0, 0); vsub->ms_not_reachable_flag = false; return; error: to_null(fi); sgs_lu_response.error = true; sgs_lu_response.vsub = vsub; vsub->sgs.response_cb(&sgs_lu_response); } /* Respawn a pending paging (Timer is reset and a new paging request is sent) */ static void respawn_paging(struct vlr_subscr *vsub) { if (vlr_sgs_pag_pend(vsub)) { /* Delete the old paging timer first. */ osmo_timer_del(&vsub->sgs.Ts5); /* Issue a fresh paging request */ vsub->sgs.paging_cb(vsub, vsub->sgs.paging_serv_ind); } } /* Figure 4.2.2.1 SGs-NULL */ static void sgs_ue_fsm_null(struct osmo_fsm_inst *fi, uint32_t event, void *data) { switch (event) { case SGS_UE_E_RX_LU_FROM_MME: perform_lu(fi); break; case SGS_UE_E_TX_PAGING: /* do nothing */ break; case SGS_UE_E_RX_PAGING_FAILURE: /* do nothing */ break; default: OSMO_ASSERT(0); } } /* Figure 4.2.2.1 SGs-LA-UPDATE-PRESENT */ static void sgs_ue_fsm_lau_present(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct vlr_subscr *vsub = fi->priv; enum sgsap_sgs_cause *cause = NULL; switch (event) { case SGS_UE_E_TX_LU_ACCEPT: vsub->conf_by_radio_contact_ind = true; vsub->sub_dataconf_by_hlr_ind = true; vsub->loc_conf_in_hlr_ind = true; vsub->la_allowed = true; vsub->imsi_detached_flag = false; if (!vsub->lu_complete) { vsub->lu_complete = true; /* Balanced by vlr_subscr_expire() */ vlr_subscr_get(vsub, VSUB_USE_ATTACHED); } vlr_sgs_fsm_update_id(vsub); vsub->cs.attached_via_ran = OSMO_RAT_EUTRAN_SGS; /* Check if we expect a TMSI REALLOCATION COMPLETE message from the MME * by checking the tmsi_new flag. If this flag is not GSM_RESERVED_TMSI * we know that we have a TMSI pending and need to wait for the MME * to acknowledge first */ if (vsub->tmsi_new != GSM_RESERVED_TMSI) { osmo_fsm_inst_state_chg(fi, SGS_UE_ST_ASSOCIATED, vsub->sgs.cfg.timer[SGS_STATE_TS6_2], SGS_STATE_TS6_2); } else { /* Trigger sending of an MM information request */ vsub->sgs.mminfo_cb(vsub); /* In cases where the LU has interrupted the paging, respawn the paging now, * See also: 3GPP TS 29.118, chapter 5.2.3.2 Location update response */ if (vlr_sgs_pag_pend(vsub)) respawn_paging(vsub); osmo_fsm_inst_state_chg(fi, SGS_UE_ST_ASSOCIATED, 0, 0); } break; case SGS_UE_E_RX_PAGING_FAILURE: cause = data; if (*cause == SGSAP_SGS_CAUSE_MT_CSFB_REJ_USER) break; to_null(fi); break; case SGS_UE_E_TX_LU_REJECT: case SGS_UE_E_RX_ALERT_FAILURE: to_null(fi); break; case SGS_UE_E_TX_PAGING: /* do nothing */ break; default: OSMO_ASSERT(0); break; } } /* Figure 4.2.2.1 SGs-ASSOCIATED */ static void sgs_ue_fsm_associated(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct vlr_subscr *vsub = fi->priv; enum sgsap_sgs_cause *cause = NULL; switch (event) { case SGS_UE_E_TX_PAGING: /* do nothing */ break; case SGS_UE_E_RX_TMSI_REALLOC: if (vsub->tmsi_new == GSM_RESERVED_TMSI) { LOGPFSML(fi, LOGL_ERROR, "(sub %s) TMSI reallocation completed at the MME, but no TMSI reallocation ordered.\n", vlr_subscr_msisdn_or_name(vsub)); } vsub->tmsi = vsub->tmsi_new; vsub->tmsi_new = GSM_RESERVED_TMSI; /* Trigger sending of MM information */ vsub->sgs.mminfo_cb(vsub); /* In cases where the LU has interrupted the paging, respawn the paging now, * See also: 3GPP TS 29.118, chapter 5.2.3.2 Location update response */ if (vlr_sgs_pag_pend(vsub)) respawn_paging(vsub); /* Note: We are already in SGS_UE_ST_ASSOCIATED but the * transition that lead us here had is guarded with Ts6-1, * so we change the state now once more without timeout * to ensure the timer is stopped */ osmo_fsm_inst_state_chg(fi, SGS_UE_ST_ASSOCIATED, 0, 0); break; case SGS_UE_E_RX_SGSAP_UE_UNREACHABLE: /* do nothing */ break; case SGS_UE_E_RX_PAGING_FAILURE: cause = data; if (*cause == SGSAP_SGS_CAUSE_MT_CSFB_REJ_USER) break; to_null(fi); break; case SGS_UE_E_RX_ALERT_FAILURE: to_null(fi); break; case SGS_UE_E_RX_LU_FROM_MME: perform_lu(fi); break; default: OSMO_ASSERT(0); break; } } /* Figure 4.2.2.1 From any of the three states (at the VLR) */ static void sgs_ue_fsm_allstate(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct vlr_subscr *vsub = fi->priv; switch (event) { case SGS_UE_E_RX_DETACH_IND_FROM_MME: case SGS_UE_E_RX_DETACH_IND_FROM_UE: vsub->imsi_detached_flag = true; vsub->expire_lu = VLR_SUBSCRIBER_NO_EXPIRATION; /* See 5.4.3 and 5.5.3 */ to_null(fi); break; case SGS_UE_E_RX_RESET_FROM_MME: /* See also 3GPP TS 29.118, chapter 5.7.2.1 VLR Reset Initiation */ vsub->conf_by_radio_contact_ind = false; to_null(fi); break; case SGS_UE_E_VLR_FAILURE: case SGS_UE_E_RX_LU_FROM_A_IU_GS: to_null(fi); break; default: OSMO_ASSERT(0); break; } } static int sgs_ue_fsm_timer_cb(struct osmo_fsm_inst *fi) { struct vlr_subscr *vsub = fi->priv; switch (fi->T) { case SGS_STATE_TS6_2: /* Failed TMSI reallocation procedure, deallocate all TMSI * information, but don't change the SGs association state. */ vsub->tmsi_new = GSM_RESERVED_TMSI; vsub->tmsi = GSM_RESERVED_TMSI; break; default: /* Unhandled timer */ OSMO_ASSERT(false); break; } return 0; } static const struct osmo_fsm_state sgs_ue_fsm_states[] = { [SGS_UE_ST_NULL] = { .name = "SGs-NULL", .action = sgs_ue_fsm_null, .in_event_mask = 0 | S(SGS_UE_E_RX_LU_FROM_MME) | S(SGS_UE_E_TX_PAGING) | S(SGS_UE_E_RX_PAGING_FAILURE) , .out_state_mask = 0 | S(SGS_UE_ST_NULL) | S(SGS_UE_ST_LA_UPD_PRES) , }, [SGS_UE_ST_LA_UPD_PRES] = { .name = "SGs-LA-UPDATE-PRESENT", .action = sgs_ue_fsm_lau_present, .in_event_mask = 0 | S(SGS_UE_E_TX_LU_ACCEPT) | S(SGS_UE_E_TX_LU_REJECT) | S(SGS_UE_E_TX_PAGING) | S(SGS_UE_E_RX_PAGING_FAILURE) | S(SGS_UE_E_RX_ALERT_FAILURE) , .out_state_mask = 0 | S(SGS_UE_ST_NULL) | S(SGS_UE_ST_ASSOCIATED) | S(SGS_UE_ST_LA_UPD_PRES) , }, [SGS_UE_ST_ASSOCIATED] = { .name = "SGs-ASSOCIATED", .action = sgs_ue_fsm_associated, .in_event_mask = 0 | S(SGS_UE_E_TX_PAGING) | S(SGS_UE_E_RX_TMSI_REALLOC) | S(SGS_UE_E_RX_SGSAP_UE_UNREACHABLE) | S(SGS_UE_E_RX_PAGING_FAILURE) | S(SGS_UE_E_RX_ALERT_FAILURE) | S(SGS_UE_E_RX_LU_FROM_MME) , .out_state_mask = 0 | S(SGS_UE_ST_NULL) | S(SGS_UE_ST_ASSOCIATED) | S(SGS_UE_ST_LA_UPD_PRES) , }, }; static struct osmo_fsm sgs_ue_fsm = { .name = "SGs-UE", .states = sgs_ue_fsm_states, .num_states = ARRAY_SIZE(sgs_ue_fsm_states), .allstate_event_mask = S(SGS_UE_E_RX_RESET_FROM_MME) | S(SGS_UE_E_VLR_FAILURE) | S(SGS_UE_E_RX_DETACH_IND_FROM_MME) | S(SGS_UE_E_RX_DETACH_IND_FROM_UE) | S(SGS_UE_E_RX_LU_FROM_A_IU_GS), .allstate_action = sgs_ue_fsm_allstate, .timer_cb = sgs_ue_fsm_timer_cb, .log_subsys = DSGS, .event_names = sgs_ue_fsm_event_names, }; /*! Initialize/Register SGs FSM in osmo-fsm subsystem */ void vlr_sgs_fsm_init(void) { if (osmo_fsm_find_by_name(sgs_ue_fsm.name) != &sgs_ue_fsm) OSMO_ASSERT(osmo_fsm_register(&sgs_ue_fsm) == 0); } /*! Crate SGs FSM in struct vlr_subscr. * \param[in] vsub VLR subscriber for which the SGs FSM should be created. */ void vlr_sgs_fsm_create(struct vlr_subscr *vsub) { char interim_fsm_id[256]; static unsigned int fsm_id_num = 0; /* An SGSs FSM must not be created twice! */ OSMO_ASSERT(!vsub->sgs_fsm); snprintf(interim_fsm_id, sizeof(interim_fsm_id), "num:%u", fsm_id_num); vsub->sgs_fsm = osmo_fsm_inst_alloc(&sgs_ue_fsm, vsub, vsub, LOGL_INFO, interim_fsm_id); OSMO_ASSERT(vsub->sgs_fsm); osmo_fsm_inst_state_chg(vsub->sgs_fsm, SGS_UE_ST_NULL, 0, 0); fsm_id_num++; } /*! Remove SGs FSM from struct vlr_subscr. * \param[in] vsub VLR subscriber from which the SGs FSM should be removed. */ void vlr_sgs_fsm_remove(struct vlr_subscr *vsub) { /* An SGSs FSM must exist! */ OSMO_ASSERT(vsub->sgs_fsm); osmo_fsm_inst_state_chg(vsub->sgs_fsm, SGS_UE_ST_NULL, 0, 0); osmo_fsm_inst_term(vsub->sgs_fsm, OSMO_FSM_TERM_REGULAR, NULL); vsub->sgs_fsm = NULL; } /*! Update the ID of the SGs FSM with the subscriber IMSI * \param[in] vsub VLR subscriber to update. */ void vlr_sgs_fsm_update_id(struct vlr_subscr *vsub) { char fsm_id[256]; if (strlen(vsub->imsi) > 0) { snprintf(fsm_id, sizeof(fsm_id), "imsi:%s", vsub->imsi); osmo_fsm_inst_update_id(vsub->sgs_fsm, fsm_id); } }