181 lines
5.1 KiB
C
181 lines
5.1 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/msc/msc_a.h>
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#include <osmocom/msc/paging.h>
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#include <osmocom/msc/transaction.h>
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#include <osmocom/msc/silent_call.h>
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#include <osmocom/sigtran/sccp_helpers.h>
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/* paging of the requested subscriber has completed */
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void paging_cb_silent(struct msc_a *msc_a, struct gsm_trans *trans)
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{
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struct scall_signal_data sigdata = {
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.msc_a = msc_a,
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.vty = trans->silent_call.from_vty,
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};
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struct ran_msg assignment;
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if (!msc_a) {
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LOG_MSC_A(msc_a, LOGL_ERROR, "Silent call: MS not responding to Paging\n");
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osmo_signal_dispatch(SS_SCALL, S_SCALL_FAILED, &sigdata);
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trans_free(trans);
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return;
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}
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LOG_MSC_A(msc_a, LOGL_INFO, "Silent call: MS responding to Paging\n");
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trans->msc_a = msc_a;
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msc_a_get(msc_a, MSC_A_USE_SILENT_CALL);
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osmo_fsm_inst_dispatch(msc_a->c.fi, MSC_A_EV_TRANSACTION_ACCEPTED, trans);
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assignment = (struct ran_msg){
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.msg_type = RAN_MSG_ASSIGNMENT_COMMAND,
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.assignment_command = {
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.channel_type = &trans->silent_call.ct,
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.cn_rtp = &trans->silent_call.rtp_cn,
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},
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};
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if (msc_a_ran_down(msc_a, MSC_ROLE_I, &assignment)) {
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LOG_MSC_A(msc_a, LOGL_ERROR, "Silent call failed\n");
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osmo_signal_dispatch(SS_SCALL, S_SCALL_FAILED, &sigdata);
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trans_free(trans);
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} else {
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osmo_signal_dispatch(SS_SCALL, S_SCALL_SUCCESS, &sigdata);
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}
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}
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void trans_silent_call_free(struct gsm_trans *trans)
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{
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struct scall_signal_data sigdata = {
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.msc_a = trans->msc_a,
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.vty = trans->silent_call.from_vty,
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};
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osmo_signal_dispatch(SS_SCALL, S_SCALL_DETACHED, &sigdata);
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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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struct vty *vty)
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{
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struct gsm_network *net = vsub->vlr->user_ctx;
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struct gsm_trans *trans = trans_alloc(net, vsub, TRANS_SILENT_CALL, 0, 0);
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trans->silent_call.ct = *ct;
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if (traffic_dst_ip) {
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osmo_sockaddr_str_from_str(&trans->silent_call.rtp_cn, traffic_dst_ip, traffic_dst_port);
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}
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trans->silent_call.from_vty = vty;
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if (!paging_request_start(vsub, PAGING_CAUSE_CALL_BACKGROUND, paging_cb_silent, trans,
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"establish silent call")) {
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trans_free(trans);
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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 msc_a *msc_a = msc_a_for_vsub(vsub, true);
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struct gsm_trans *trans;
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if (!msc_a) {
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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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trans = trans_find_by_type(msc_a, TRANS_SILENT_CALL);
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if (!trans) {
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LOG_MSC_A(msc_a, LOGL_ERROR, "Cannot stop silent call, subscriber has no active silent call\n");
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return -ENOENT;
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}
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trans_free(trans);
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return 0;
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}
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