306 lines
8.4 KiB
C
306 lines
8.4 KiB
C
/* Handle LCS BSSLAP TA Request */
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/*
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* (C) 2020 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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* All Rights Reserved
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*
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* Author: Neels Hofmeyr <neels@hofmeyr.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <osmocom/bsc/lcs_ta_req.h>
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#include <osmocom/bsc/lcs_loc_req.h>
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#include <osmocom/bsc/lb.h>
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#include <osmocom/bsc/gsm_data.h>
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#include <osmocom/bsc/paging.h>
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#include <osmocom/bsc/bts.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/core/fsm.h>
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#include <osmocom/core/tdef.h>
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#include <osmocom/gsm/bsslap.h>
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enum lcs_ta_req_fsm_state {
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LCS_TA_REQ_ST_INIT,
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LCS_TA_REQ_ST_WAIT_TA,
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LCS_TA_REQ_ST_GOT_TA,
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LCS_TA_REQ_ST_FAILED,
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};
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static const struct value_string lcs_ta_req_fsm_event_names[] = {
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OSMO_VALUE_STRING(LCS_TA_REQ_EV_GOT_TA),
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OSMO_VALUE_STRING(LCS_TA_REQ_EV_ABORT),
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{}
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};
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static const struct osmo_tdef_state_timeout lcs_ta_req_fsm_timeouts[32] = {
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[LCS_TA_REQ_ST_WAIT_TA] = { .T = -12 },
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};
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/* Transition to a state, using the T timer defined in lcs_ta_req_fsm_timeouts.
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* The actual timeout value is in turn obtained from network->T_defs.
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* Assumes local variable fi exists. */
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#define lcs_ta_req_fsm_state_chg(FI, STATE) \
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osmo_tdef_fsm_inst_state_chg(FI, STATE, \
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lcs_ta_req_fsm_timeouts, \
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(bsc_gsmnet)->T_defs, \
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-1)
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#define lcs_ta_req_fail(cause, fmt, args...) do { \
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LOG_LCS_TA_REQ(lcs_ta_req, LOGL_ERROR, "BSSLAP TA Request failed in state %s: " fmt "\n", \
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lcs_ta_req ? osmo_fsm_inst_state_name(lcs_ta_req->fi) : "NULL", ## args); \
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lcs_ta_req->failure_cause = cause; \
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lcs_ta_req_fsm_state_chg(lcs_ta_req->fi, LCS_TA_REQ_ST_FAILED); \
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} while (0)
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static struct osmo_fsm lcs_ta_req_fsm;
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static struct lcs_ta_req *lcs_ta_req_alloc(struct osmo_fsm_inst *parent_fi, uint32_t parent_event_term)
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{
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struct lcs_ta_req *lcs_ta_req;
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struct osmo_fsm_inst *fi = osmo_fsm_inst_alloc_child(&lcs_ta_req_fsm, parent_fi, parent_event_term);
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OSMO_ASSERT(fi);
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lcs_ta_req = talloc(fi, struct lcs_ta_req);
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OSMO_ASSERT(lcs_ta_req);
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fi->priv = lcs_ta_req;
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*lcs_ta_req = (struct lcs_ta_req){
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.fi = fi,
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};
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return lcs_ta_req;
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}
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int lcs_ta_req_start(struct lcs_loc_req *lcs_loc_req)
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{
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struct lcs_ta_req *lcs_ta_req;
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if (lcs_loc_req->ta_req) {
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LOG_LCS_TA_REQ(lcs_loc_req->ta_req, LOGL_ERROR,
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"Cannot start anoter TA Request FSM, this TA Request is still active\n");
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return -ENOTSUP;
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}
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lcs_ta_req = lcs_ta_req_alloc(lcs_loc_req->fi, LCS_LOC_REQ_EV_TA_REQ_END);
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if (!lcs_ta_req) {
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LOG_LCS_LOC_REQ(lcs_loc_req, LOGL_ERROR, "Cannot allocate TA Request FSM");
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return -ENOSPC;
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}
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lcs_ta_req->loc_req = lcs_loc_req;
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lcs_loc_req->ta_req = lcs_ta_req;
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return lcs_ta_req_fsm_state_chg(lcs_ta_req->fi, LCS_TA_REQ_ST_WAIT_TA);
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}
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static int lcs_ta_req_fsm_timer_cb(struct osmo_fsm_inst *fi)
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{
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struct lcs_ta_req *lcs_ta_req = fi->priv;
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lcs_ta_req_fail(LCS_CAUSE_SYSTEM_FAILURE, "Timeout");
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return 1;
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}
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void lcs_ta_req_wait_ta_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
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{
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struct lcs_ta_req *lcs_ta_req = fi->priv;
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struct lcs_loc_req *loc_req = lcs_ta_req->loc_req;
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struct gsm_lchan *lchan;
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struct bsc_paging_params paging;
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if (osmo_fsm_inst_dispatch(loc_req->fi, LCS_LOC_REQ_EV_TA_REQ_START, lcs_ta_req)) {
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lcs_ta_req_fail(LCS_CAUSE_SYSTEM_FAILURE, "Failed to dispatch LCS_LOC_REQ_EV_TA_REQ_START");
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return;
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}
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/* Do we already have an active lchan with knowledge of TA? */
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lchan = loc_req->conn->lchan;
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if (lchan) {
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lcs_ta_req_fsm_state_chg(fi, LCS_TA_REQ_ST_GOT_TA);
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return;
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}
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/* No lchan yet, need to start Paging */
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if (loc_req->req.imsi.type != GSM_MI_TYPE_IMSI) {
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lcs_ta_req_fail(LCS_CAUSE_PROTOCOL_ERROR,
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"No IMSI in BSSMAP Location Request and no active lchan, cannot start Paging");
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return;
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}
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paging = (struct bsc_paging_params){
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.reason = BSC_PAGING_FOR_LCS,
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.msc = loc_req->conn->sccp.msc,
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.bsub = loc_req->conn->bsub,
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.tmsi = GSM_RESERVED_TMSI,
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.imsi = loc_req->req.imsi,
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.chan_needed = RSL_CHANNEED_ANY,
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};
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if (paging.bsub)
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bsc_subscr_get(paging.bsub, BSUB_USE_PAGING_START);
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if (!loc_req->req.cell_id_present) {
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LOG_LCS_TA_REQ(lcs_ta_req, LOGL_DEBUG,
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"No Cell Identity in BSSMAP Location Request, paging entire BSS\n");
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paging.cil = (struct gsm0808_cell_id_list2){
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.id_discr = CELL_IDENT_BSS,
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};
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} else {
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paging.cil = (struct gsm0808_cell_id_list2){
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.id_discr = loc_req->req.cell_id.id_discr,
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.id_list = { loc_req->req.cell_id.id },
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.id_list_len = 1,
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};
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}
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bsc_paging_start(&paging);
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}
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static void lcs_ta_req_wait_ta_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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switch (event) {
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case LCS_TA_REQ_EV_GOT_TA:
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lcs_ta_req_fsm_state_chg(fi, LCS_TA_REQ_ST_GOT_TA);
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break;
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case LCS_TA_REQ_EV_ABORT:
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lcs_ta_req_fsm_state_chg(fi, LCS_TA_REQ_ST_FAILED);
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break;
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default:
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OSMO_ASSERT(false);
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}
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}
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static int lcs_ta_req_send(struct lcs_ta_req *lcs_ta_req, const struct bssap_le_pdu *bssap_le)
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{
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int rc = lb_send(lcs_ta_req->loc_req->conn, bssap_le);
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if (rc)
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lcs_ta_req_fail(LCS_CAUSE_SYSTEM_FAILURE,
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"Failed to send %s", osmo_bssap_le_pdu_to_str_c(OTC_SELECT, bssap_le));
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return rc;
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}
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void lcs_ta_req_got_ta_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
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{
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struct lcs_ta_req *lcs_ta_req = fi->priv;
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struct bssap_le_pdu bsslap_ta_resp;
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struct gsm_lchan *lchan = lcs_ta_req->loc_req->conn->lchan;
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if (!lchan) {
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lcs_ta_req_fail(LCS_CAUSE_SYSTEM_FAILURE, "Internal error: no lchan");
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return;
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}
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bsslap_ta_resp = (struct bssap_le_pdu) {
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.discr = BSSAP_LE_MSG_DISCR_BSSMAP_LE,
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.bssmap_le = {
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.msg_type = BSSMAP_LE_MSGT_CONN_ORIENTED_INFO,
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.conn_oriented_info = {
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.apdu = {
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.msg_type = BSSLAP_MSGT_TA_RESPONSE,
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.ta_response = {
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.cell_id = lchan->ts->trx->bts->cell_identity,
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.ta = lchan->last_ta,
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},
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},
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},
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},
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};
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lcs_ta_req_send(lcs_ta_req, &bsslap_ta_resp);
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osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REGULAR, NULL);
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}
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void lcs_ta_req_failed_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
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{
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struct lcs_ta_req *lcs_ta_req = fi->priv;
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struct bssap_le_pdu bsslap_abort;
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bsslap_abort = (struct bssap_le_pdu) {
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.discr = BSSAP_LE_MSG_DISCR_BSSMAP_LE,
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.bssmap_le = {
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.msg_type = BSSMAP_LE_MSGT_CONN_ORIENTED_INFO,
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.conn_oriented_info = {
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.apdu = {
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.msg_type = BSSLAP_MSGT_ABORT,
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.abort = BSSLAP_CAUSE_OTHER_RADIO_EVT_FAIL,
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},
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},
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},
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};
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lcs_ta_req_send(lcs_ta_req, &bsslap_abort);
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osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
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}
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void lcs_ta_req_fsm_cleanup(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause cause)
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{
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struct lcs_ta_req *lcs_ta_req = fi->priv;
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if (lcs_ta_req->loc_req->ta_req == lcs_ta_req)
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lcs_ta_req->loc_req->ta_req = NULL;
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/* FSM termination will dispatch LCS_LOC_REQ_EV_TA_REQ_END to the lcs_loc_req FSM */
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}
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#define S(x) (1 << (x))
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static const struct osmo_fsm_state lcs_ta_req_fsm_states[] = {
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[LCS_TA_REQ_ST_INIT] = {
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.name = "init",
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.out_state_mask = 0
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| S(LCS_TA_REQ_ST_WAIT_TA)
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| S(LCS_TA_REQ_ST_GOT_TA)
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,
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},
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[LCS_TA_REQ_ST_WAIT_TA] = {
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.name = "wait_ta",
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.in_event_mask = 0
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| S(LCS_TA_REQ_EV_GOT_TA)
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| S(LCS_TA_REQ_EV_ABORT)
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,
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.out_state_mask = 0
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| S(LCS_TA_REQ_ST_GOT_TA)
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| S(LCS_TA_REQ_ST_FAILED)
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,
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.onenter = lcs_ta_req_wait_ta_onenter,
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.action = lcs_ta_req_wait_ta_action,
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},
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[LCS_TA_REQ_ST_GOT_TA] = {
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.name = "got_ta",
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.in_event_mask = 0
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,
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.out_state_mask = 0
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,
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.onenter = lcs_ta_req_got_ta_onenter,
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},
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[LCS_TA_REQ_ST_FAILED] = {
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.name = "failed",
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.onenter = lcs_ta_req_failed_onenter,
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},
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};
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static struct osmo_fsm lcs_ta_req_fsm = {
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.name = "lcs_ta_req",
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.states = lcs_ta_req_fsm_states,
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.num_states = ARRAY_SIZE(lcs_ta_req_fsm_states),
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.log_subsys = DLCS,
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.event_names = lcs_ta_req_fsm_event_names,
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.timer_cb = lcs_ta_req_fsm_timer_cb,
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.cleanup = lcs_ta_req_fsm_cleanup,
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};
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static __attribute__((constructor)) void lcs_ta_req_fsm_register(void)
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{
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OSMO_ASSERT(osmo_fsm_register(&lcs_ta_req_fsm) == 0);
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}
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