254 lines
6.9 KiB
C
254 lines
6.9 KiB
C
/* GSM silent call feature */
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/*
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* (C) 2009 by Harald Welte <laforge@gnumonks.org>
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*
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* All Rights Reserved
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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 <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <osmocom/core/byteswap.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/msc/signal.h>
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#include <osmocom/msc/debug.h>
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#include <osmocom/msc/gsm_data.h>
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#include <osmocom/msc/gsm_subscriber.h>
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#include <osmocom/msc/vlr.h>
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#include <osmocom/sigtran/sccp_helpers.h>
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struct silent_call_data {
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struct gsm0808_channel_type ct;
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char traffic_ip[INET_ADDRSTRLEN];
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uint16_t traffic_port;
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void *data;
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struct osmo_timer_list timer;
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struct ran_conn *conn;
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};
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static void timer_cb(void *data)
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{
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struct silent_call_data *scd = (struct silent_call_data *)data;
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ran_conn_communicating(scd->conn);
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talloc_free(scd);
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}
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/* paging of the requested subscriber has completed */
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static int paging_cb_silent(unsigned int hooknum, unsigned int event,
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struct msgb *msg, void *_conn, void *_data)
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{
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struct silent_call_data *scd = (struct silent_call_data *)_data;
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struct ran_conn *conn = _conn;
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struct scall_signal_data sigdata;
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struct msgb *msg_ass;
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int rc = 0;
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int i;
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if (hooknum != GSM_HOOK_RR_PAGING)
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return -EINVAL;
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DEBUGP(DLSMS, "paging_cb_silent: ");
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sigdata.conn = conn;
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sigdata.data = scd->data;
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switch (event) {
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case GSM_PAGING_SUCCEEDED:
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#if BEFORE_MSCSPLIT
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/* Re-enable this log output once we can obtain this information via
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* A-interface, see OS#2391. */
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DEBUGPC(DLSMS, "success, using Timeslot %u on ARFCN %u\n",
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conn->lchan->ts->nr, conn->lchan->ts->trx->arfcn);
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#endif
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conn->silent_call = 1;
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/* Increment lchan reference count and mark as active*/
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ran_conn_get(conn, RAN_CONN_USE_SILENT_CALL);
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/* Schedule a timer to mark it as active */
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/* This is a hack we we can't call ran_conn_communicating
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* from here because we're in the call back context of
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* a RAN FSM event but before it actually changes its own
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* state and it's not ready to accept this.
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* Of all alternatives considered, making the call in an
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* 'immediate timer' is the least disruptive and least ugly
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* way to do it I could find.
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*/
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scd->conn = conn;
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osmo_timer_setup(&scd->timer, timer_cb, scd);
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osmo_timer_schedule(&scd->timer, 0, 0);
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/* Manually craft an assignement message with requested mode */
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if (scd->ct.ch_indctr == GSM0808_CHAN_SPEECH) {
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struct gsm0808_speech_codec_list scl;
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union {
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struct sockaddr_storage st;
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struct sockaddr_in in;
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} rtp_addr;
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memset(&rtp_addr, 0, sizeof(rtp_addr));
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rtp_addr.in.sin_family = AF_INET;
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rtp_addr.in.sin_port = osmo_htons(scd->traffic_port);
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rtp_addr.in.sin_addr.s_addr = inet_addr(scd->traffic_ip);
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for (i = 0; i < scd->ct.perm_spch_len; i++)
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gsm0808_speech_codec_from_chan_type(&scl.codec[i], scd->ct.perm_spch[i]);
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scl.len = scd->ct.perm_spch_len;
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msg_ass = gsm0808_create_ass(&scd->ct, NULL, &rtp_addr.st, &scl, NULL);
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} else {
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msg_ass = gsm0808_create_ass(&scd->ct, NULL, NULL, NULL, NULL);
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}
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/* Send assignement message, hoping it will work */
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osmo_sccp_tx_data_msg(conn->a.scu, conn->a.conn_id, msg_ass);
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/* Signal completion */
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osmo_signal_dispatch(SS_SCALL, S_SCALL_SUCCESS, &sigdata);
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return 0;
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case GSM_PAGING_EXPIRED:
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case GSM_PAGING_BUSY:
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DEBUGP(DLSMS, "expired\n");
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osmo_signal_dispatch(SS_SCALL, S_SCALL_EXPIRED, &sigdata);
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break;
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default:
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rc = -EINVAL;
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break;
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}
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talloc_free(scd);
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return rc;
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}
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#if 0
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/* receive a layer 3 message from a silent call */
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int silent_call_rx(struct ran_conn *conn, struct msgb *msg)
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{
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/* FIXME: do something like sending it through a UDP port */
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LOGP(DLSMS, LOGL_NOTICE, "Discarding L3 message from a silent call.\n");
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return 0;
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}
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struct msg_match {
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uint8_t pdisc;
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uint8_t msg_type;
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};
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/* list of messages that are handled inside OpenBSC, even in a silent call */
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static const struct msg_match silent_call_accept[] = {
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{ GSM48_PDISC_MM, GSM48_MT_MM_LOC_UPD_REQUEST },
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{ GSM48_PDISC_MM, GSM48_MT_MM_CM_SERV_REQ },
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};
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/* decide if we need to reroute a message as part of a silent call */
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int silent_call_reroute(struct ran_conn *conn, struct msgb *msg)
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{
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struct gsm48_hdr *gh = msgb_l3(msg);
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uint8_t pdisc = gsm48_hdr_pdisc(gh);
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uint8_t msg_type = gsm48_hdr_msg_type(gh);
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int i;
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/* if we're not part of a silent call, never reroute */
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if (!conn->silent_call)
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return 0;
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/* check if we are a special message that is handled in openbsc */
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for (i = 0; i < ARRAY_SIZE(silent_call_accept); i++) {
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if (silent_call_accept[i].pdisc == pdisc &&
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silent_call_accept[i].msg_type == msg_type)
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return 0;
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}
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/* otherwise, reroute */
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LOGP(DLSMS, LOGL_INFO, "Rerouting L3 message from a silent call.\n");
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return 1;
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}
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#endif
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/* initiate a silent call with a given subscriber */
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int gsm_silent_call_start(struct vlr_subscr *vsub,
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const struct gsm0808_channel_type *ct,
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const char *traffic_dst_ip, uint16_t traffic_dst_port,
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void *data)
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{
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struct subscr_request *req;
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struct silent_call_data *scd;
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scd = talloc_zero(vsub, struct silent_call_data);
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memcpy(&scd->ct, ct, sizeof(scd->ct));
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if (traffic_dst_ip) {
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osmo_strlcpy(scd->traffic_ip, traffic_dst_ip, sizeof(scd->traffic_ip));
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scd->traffic_port = traffic_dst_port;
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}
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scd->data = data;
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req = subscr_request_conn(vsub, paging_cb_silent, scd,
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"establish silent call",
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SGSAP_SERV_IND_CS_CALL);
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if (!req) {
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talloc_free(scd);
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return -ENODEV;
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}
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return 0;
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}
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/* end a silent call with a given subscriber */
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int gsm_silent_call_stop(struct vlr_subscr *vsub)
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{
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struct ran_conn *conn;
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conn = connection_for_subscr(vsub);
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if (!conn) {
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LOGP(DMM, LOGL_ERROR, "%s: Cannot stop silent call, no connection for subscriber\n",
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vlr_subscr_name(vsub));
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return -ENODEV;
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}
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/* did we actually establish a silent call for this guy? */
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if (!conn->silent_call) {
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LOGP(DMM, LOGL_ERROR, "%s: Cannot stop silent call, subscriber has no active silent call\n",
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vlr_subscr_name(vsub));
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return -ENOENT;
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}
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#if BEFORE_MSCSPLIT
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/* Re-enable this log output once we can obtain this information via
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* A-interface, see OS#2391. */
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DEBUGPC(DLSMS, "Stopping silent call using Timeslot %u on ARFCN %u\n",
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conn->lchan->ts->nr, conn->lchan->ts->trx->arfcn);
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#endif
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conn->silent_call = 0;
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ran_conn_put(conn, RAN_CONN_USE_SILENT_CALL);
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return 0;
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}
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