427 lines
12 KiB
C
427 lines
12 KiB
C
/* Implementation for MSC decisions which interface to send messages out on. */
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/* (C) 2016 by sysmocom s.m.f.c GmbH <info@sysmocom.de>
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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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#include <osmocom/core/logging.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/msc_ifaces.h>
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#include <osmocom/msc/gsm_subscriber.h>
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#include <osmocom/msc/transaction.h>
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#include <osmocom/legacy_mgcp/mgcp.h>
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#include <osmocom/mgcp_client/mgcp_client.h>
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#include <osmocom/msc/vlr.h>
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#include <osmocom/msc/a_iface.h>
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#include "../../bscconfig.h"
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#ifdef BUILD_IU
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#include <osmocom/ranap/iu_client.h>
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extern struct msgb *ranap_new_msg_rab_assign_voice(uint8_t rab_id,
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uint32_t rtp_ip,
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uint16_t rtp_port,
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bool use_x213_nsap);
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#else
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#include <osmocom/msc/iu_dummy.h>
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#endif /* BUILD_IU */
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static int msc_tx(struct gsm_subscriber_connection *conn, struct msgb *msg)
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{
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if (!msg)
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return -EINVAL;
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if (!conn) {
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msgb_free(msg);
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return -EINVAL;
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}
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DEBUGP(DMSC, "msc_tx %u bytes to %s via %s\n",
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msg->len, vlr_subscr_name(conn->vsub),
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ran_type_name(conn->via_ran));
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switch (conn->via_ran) {
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case RAN_GERAN_A:
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msg->dst = conn;
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return a_iface_tx_dtap(msg);
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case RAN_UTRAN_IU:
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msg->dst = conn->iu.ue_ctx;
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return ranap_iu_tx(msg, 0);
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default:
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LOGP(DMSC, LOGL_ERROR,
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"msc_tx(): conn->via_ran invalid (%d)\n",
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conn->via_ran);
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msgb_free(msg);
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return -1;
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}
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}
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int msc_tx_dtap(struct gsm_subscriber_connection *conn,
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struct msgb *msg)
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{
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return msc_tx(conn, msg);
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}
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/* 9.2.5 CM service accept */
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int msc_gsm48_tx_mm_serv_ack(struct gsm_subscriber_connection *conn)
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{
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struct msgb *msg;
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struct gsm48_hdr *gh;
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if (!conn)
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return -EINVAL;
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msg = gsm48_msgb_alloc_name("GSM 04.08 SERV ACC");
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gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh));
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gh->proto_discr = GSM48_PDISC_MM;
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gh->msg_type = GSM48_MT_MM_CM_SERV_ACC;
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DEBUGP(DMM, "-> CM SERVICE ACCEPT %s\n",
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vlr_subscr_name(conn->vsub));
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return msc_tx_dtap(conn, msg);
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}
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/* 9.2.6 CM service reject */
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int msc_gsm48_tx_mm_serv_rej(struct gsm_subscriber_connection *conn,
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enum gsm48_reject_value value)
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{
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struct msgb *msg;
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if (!conn)
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return -EINVAL;
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conn->received_cm_service_request = false;
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msg = gsm48_create_mm_serv_rej(value);
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if (!msg) {
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LOGP(DMM, LOGL_ERROR, "Failed to allocate CM Service Reject.\n");
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return -1;
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}
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DEBUGP(DMM, "-> CM SERVICE Reject cause: %d\n", value);
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return msc_tx_dtap(conn, msg);
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}
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int msc_tx_common_id(struct gsm_subscriber_connection *conn)
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{
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if (!conn)
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return -EINVAL;
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/* Common ID is only sent over IuCS */
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if (conn->via_ran != RAN_UTRAN_IU) {
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LOGP(DMM, LOGL_INFO,
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"%s: Asked to transmit Common ID, but skipping"
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" because this is not on UTRAN\n",
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vlr_subscr_name(conn->vsub));
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return 0;
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}
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DEBUGP(DIUCS, "%s: tx CommonID %s\n",
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vlr_subscr_name(conn->vsub), conn->vsub->imsi);
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return ranap_iu_tx_common_id(conn->iu.ue_ctx, conn->vsub->imsi);
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}
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static int iu_rab_act_cs(struct ranap_ue_conn_ctx *uectx, uint8_t rab_id,
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uint32_t rtp_ip, uint16_t rtp_port)
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{
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#ifdef BUILD_IU
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struct msgb *msg;
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bool use_x213_nsap;
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uint32_t conn_id = uectx->conn_id;
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use_x213_nsap = (uectx->rab_assign_addr_enc == RANAP_NSAP_ADDR_ENC_X213);
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LOGP(DIUCS, LOGL_DEBUG, "Assigning RAB: conn_id=%u, rab_id=%d,"
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" rtp=%x:%u, use_x213_nsap=%d\n", conn_id, rab_id, rtp_ip,
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rtp_port, use_x213_nsap);
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msg = ranap_new_msg_rab_assign_voice(rab_id, rtp_ip, rtp_port,
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use_x213_nsap);
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msg->l2h = msg->data;
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if (ranap_iu_rab_act(uectx, msg))
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LOGP(DIUCS, LOGL_ERROR, "Failed to send RAB Assignment:"
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" conn_id=%d rab_id=%d rtp=%x:%u\n",
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conn_id, rab_id, rtp_ip, rtp_port);
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return 0;
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#else
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LOGP(DMSC, LOGL_ERROR, "Cannot send Iu RAB Assignment: built without Iu support\n");
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return -ENOTSUP;
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#endif
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}
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static void mgcp_response_rab_act_cs_crcx(struct mgcp_response *r, void *priv)
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{
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struct gsm_trans *trans = priv;
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struct gsm_subscriber_connection *conn = trans->conn;
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uint32_t rtp_ip;
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int rc;
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if (r->head.response_code != 200) {
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LOGP(DMGCP, LOGL_ERROR,
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"MGCPGW response yields error: %d %s\n",
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r->head.response_code, r->head.comment);
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goto rab_act_cs_error;
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}
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rc = mgcp_response_parse_params(r);
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if (rc) {
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LOGP(DMGCP, LOGL_ERROR,
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"Cannot parse MGCP response, for %s\n",
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vlr_subscr_name(trans->vsub));
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goto rab_act_cs_error;
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}
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conn->rtp.port_cn = r->audio_port;
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rtp_ip = mgcp_client_remote_addr_n(conn->network->mgw.client);
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if (trans->conn->via_ran == RAN_UTRAN_IU) {
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/* Assign a voice channel via RANAP on 3G */
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if (iu_rab_act_cs(conn->iu.ue_ctx, conn->iu.rab_id, rtp_ip, conn->rtp.port_subscr))
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goto rab_act_cs_error;
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} else if (trans->conn->via_ran == RAN_GERAN_A) {
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/* Assign a voice channel via A on 2G */
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if (a_iface_tx_assignment(trans))
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goto rab_act_cs_error;
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} else
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goto rab_act_cs_error;
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/* Respond back to MNCC (if requested) */
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if (trans->tch_rtp_create) {
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if (gsm48_tch_rtp_create(trans))
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goto rab_act_cs_error;
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}
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return;
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rab_act_cs_error:
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/* FIXME abort call, invalidate conn, ... */
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LOGP(DMSC, LOGL_ERROR, "%s: failure during assignment\n",
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vlr_subscr_name(trans->vsub));
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return;
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}
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int msc_call_assignment(struct gsm_trans *trans)
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{
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struct gsm_subscriber_connection *conn;
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struct mgcp_client *mgcp;
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struct msgb *msg;
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uint16_t bts_base;
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if (!trans)
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return -EINVAL;
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if (!trans->conn)
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return -EINVAL;
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conn = trans->conn;
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mgcp = conn->network->mgw.client;
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#ifdef BUILD_IU
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/* FIXME: HACK. where to scope the RAB Id? At the conn / subscriber / ranap_ue_conn_ctx? */
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static uint8_t next_iu_rab_id = 1;
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if (conn->via_ran == RAN_UTRAN_IU)
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conn->iu.rab_id = next_iu_rab_id ++;
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#endif
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conn->rtp.mgcp_rtp_endpoint =
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mgcp_client_next_endpoint(conn->network->mgw.client);
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/* This will calculate the port we assign to the BTS via AoIP
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* assignment command (or rab-assignment on 3G) The BTS will send
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* its RTP traffic to that port on the MGCPGW side. The MGCPGW only
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* gets the endpoint ID via the CRCX. It will do the same calculation
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* on his side too to get knowledge of the rtp port. */
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bts_base = mgcp_client_conf_actual(mgcp)->bts_base;
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conn->rtp.port_subscr = bts_base + 2 * conn->rtp.mgcp_rtp_endpoint;
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/* Establish the RTP stream first as looping back to the originator.
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* The MDCX will patch through to the counterpart. TODO: play a ring
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* tone instead. */
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msg = mgcp_msg_crcx(mgcp, conn->rtp.mgcp_rtp_endpoint,
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conn->rtp.mgcp_rtp_endpoint, MGCP_CONN_LOOPBACK);
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return mgcp_client_tx(mgcp, msg, mgcp_response_rab_act_cs_crcx, trans);
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}
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static void mgcp_response_bridge_mdcx(struct mgcp_response *r, void *priv);
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static void mgcp_bridge(struct gsm_trans *from, struct gsm_trans *to,
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enum bridge_state state,
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enum mgcp_connection_mode mode)
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{
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struct gsm_subscriber_connection *conn1 = from->conn;
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struct gsm_subscriber_connection *conn2 = to->conn;
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struct mgcp_client *mgcp = conn1->network->mgw.client;
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const char *ip;
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struct msgb *msg;
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OSMO_ASSERT(mgcp);
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from->bridge.peer = to;
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from->bridge.state = state;
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/* Loop back to the same MGCP GW */
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ip = mgcp_client_remote_addr_str(mgcp);
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msg = mgcp_msg_mdcx(mgcp,
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conn1->rtp.mgcp_rtp_endpoint,
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ip, conn2->rtp.port_cn,
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mode);
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if (mgcp_client_tx(mgcp, msg, mgcp_response_bridge_mdcx, from))
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LOGP(DMGCP, LOGL_ERROR,
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"Failed to send MDCX message for %s\n",
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vlr_subscr_name(from->vsub));
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}
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static void mgcp_response_bridge_mdcx(struct mgcp_response *r, void *priv)
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{
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struct gsm_trans *trans = priv;
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struct gsm_trans *peer = trans->bridge.peer;
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switch (trans->bridge.state) {
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case BRIDGE_STATE_LOOPBACK_PENDING:
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trans->bridge.state = BRIDGE_STATE_LOOPBACK_ESTABLISHED;
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switch (peer->bridge.state) {
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case BRIDGE_STATE_LOOPBACK_PENDING:
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/* Wait until the other is done as well. */
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return;
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case BRIDGE_STATE_LOOPBACK_ESTABLISHED:
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/* Now that both are in loopback, switch both to
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* forwarding. */
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mgcp_bridge(trans, peer, BRIDGE_STATE_BRIDGE_PENDING,
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MGCP_CONN_RECV_SEND);
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mgcp_bridge(peer, trans, BRIDGE_STATE_BRIDGE_PENDING,
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MGCP_CONN_RECV_SEND);
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break;
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default:
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LOGP(DMGCP, LOGL_ERROR,
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"Unexpected bridge state: %d for %s\n",
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trans->bridge.state, vlr_subscr_name(trans->vsub));
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break;
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}
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break;
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case BRIDGE_STATE_BRIDGE_PENDING:
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trans->bridge.state = BRIDGE_STATE_BRIDGE_ESTABLISHED;
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break;
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default:
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LOGP(DMGCP, LOGL_ERROR,
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"Unexpected bridge state: %d for %s\n",
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trans->bridge.state, vlr_subscr_name(trans->vsub));
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break;
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}
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}
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int msc_call_connect(struct gsm_trans *trans, uint16_t port, uint32_t ip)
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{
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/* With this function we inform the MGCP-GW where (ip/port) it
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* has to send its outgoing voic traffic. The receiving end will
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* usually be a PBX (e.g. Asterisk). The IP-Address we tell, will
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* not only be used to direct the traffic, it will also be used
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* as a filter to make sure only RTP packets from the right
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* remote end will reach the BSS. This is also the reason why
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* inbound audio will not work until this step is performed */
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/* NOTE: This function is used when msc_call_bridge(), is not
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* applicable. This is usually the case when an external MNCC
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* is in use */
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struct gsm_subscriber_connection *conn;
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struct mgcp_client *mgcp;
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struct msgb *msg;
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if (!trans)
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return -EINVAL;
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if (!trans->conn)
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return -EINVAL;
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if (!trans->conn->network)
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return -EINVAL;
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if (!trans->conn->network->mgw.client)
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return -EINVAL;
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mgcp = trans->conn->network->mgw.client;
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struct in_addr ip_addr;
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ip_addr.s_addr = ntohl(ip);
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conn = trans->conn;
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msg = mgcp_msg_mdcx(mgcp,
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conn->rtp.mgcp_rtp_endpoint,
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inet_ntoa(ip_addr), port, MGCP_CONN_RECV_SEND);
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if (mgcp_client_tx(mgcp, msg, NULL, trans))
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LOGP(DMGCP, LOGL_ERROR,
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"Failed to send MDCX message for %s\n",
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vlr_subscr_name(trans->vsub));
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return 0;
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}
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int msc_call_bridge(struct gsm_trans *trans1, struct gsm_trans *trans2)
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{
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if (!trans1)
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return -EINVAL;
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if (!trans2)
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return -EINVAL;
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/* First setup as loopback and configure the counterparts' endpoints,
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* so that when transmission starts the originating addresses are
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* already known to be valid. The mgcp callback will continue. */
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mgcp_bridge(trans1, trans2, BRIDGE_STATE_LOOPBACK_PENDING,
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MGCP_CONN_LOOPBACK);
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mgcp_bridge(trans2, trans1, BRIDGE_STATE_LOOPBACK_PENDING,
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MGCP_CONN_LOOPBACK);
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return 0;
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}
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void msc_call_release(struct gsm_trans *trans)
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{
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struct msgb *msg;
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struct gsm_subscriber_connection *conn;
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struct mgcp_client *mgcp;
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if (!trans)
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return;
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if (!trans->conn)
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return;
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if (!trans->conn->network)
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return;
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conn = trans->conn;
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mgcp = conn->network->mgw.client;
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/* Send DLCX */
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msg = mgcp_msg_dlcx(mgcp, conn->rtp.mgcp_rtp_endpoint,
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conn->rtp.mgcp_rtp_endpoint);
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if (mgcp_client_tx(mgcp, msg, NULL, NULL))
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LOGP(DMGCP, LOGL_ERROR,
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"Failed to send DLCX message for %s\n",
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vlr_subscr_name(trans->vsub));
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/* Release endpoint id */
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mgcp_client_release_endpoint(conn->rtp.mgcp_rtp_endpoint, mgcp);
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}
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