524 lines
15 KiB
C
524 lines
15 KiB
C
/* The routines to handle the state */
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/*
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* (C) 2010-2011 by Holger Hans Peter Freyther <zecke@selfish.org>
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* (C) 2010-2011 by On-Waves
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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 <mtp_data.h>
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#include <msc_connection.h>
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#include <mtp_level3.h>
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#include <bss_patch.h>
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#include <bssap_sccp.h>
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#include <bsc_data.h>
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#include <cellmgr_debug.h>
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#include <bsc_sccp.h>
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#include <osmocore/talloc.h>
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#include <osmocom/vty/vty.h>
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#include <osmocom/vty/telnet_interface.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <unistd.h>
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static void send_reset_ack(struct mtp_link_set *link, int sls);
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static void bsc_resources_released(struct msc_connection *bsc);
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static void handle_local_sccp(struct mtp_link_set *link, struct msgb *inp, struct sccp_parse_result *res, int sls);
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static void clear_connections(struct msc_connection *bsc);
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static void send_local_rlsd(struct mtp_link_set *link, struct sccp_parse_result *res);
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/* send a RSIP to the MGCP GW */
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static void mgcp_reset(struct msc_connection *fw)
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{
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static const char mgcp_reset[] = {
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"RSIP 1 13@mgw MGCP 1.0\r\n"
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};
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mgcp_forward(fw, (const uint8_t *) mgcp_reset, strlen(mgcp_reset));
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}
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/*
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* methods called from the MTP Level3 part
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*/
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void mtp_link_set_forward_sccp(struct mtp_link_set *link, struct msgb *_msg, int sls)
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{
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int rc;
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struct sccp_parse_result result;
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struct msc_connection *fw = link->fw;
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if (fw->forward_only) {
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msc_send_direct(fw, _msg);
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return;
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}
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rc = bss_patch_filter_msg(_msg, &result);
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if (rc == BSS_FILTER_RESET) {
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LOGP(DMSC, LOGL_NOTICE, "Filtering BSS Reset from the BSC\n");
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mgcp_reset(fw);
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send_reset_ack(link, sls);
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return;
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}
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/* special responder */
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if (fw->msc_link_down) {
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if (rc == BSS_FILTER_RESET_ACK && fw->reset_count > 0) {
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LOGP(DMSC, LOGL_ERROR, "Received reset ack for closing.\n");
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clear_connections(fw);
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bsc_resources_released(fw);
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return;
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}
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if (rc != 0 && rc != BSS_FILTER_RLSD && rc != BSS_FILTER_RLC) {
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LOGP(DMSC, LOGL_ERROR, "Ignoring unparsable msg during closedown.\n");
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return;
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}
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return handle_local_sccp(link, _msg, &result, sls);
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}
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/* update the connection state */
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update_con_state(link->fw, rc, &result, _msg, 0, sls);
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if (rc == BSS_FILTER_CLEAR_COMPL) {
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send_local_rlsd(link, &result);
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} else if (rc == BSS_FILTER_RLC || rc == BSS_FILTER_RLSD) {
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LOGP(DMSC, LOGL_DEBUG, "Not forwarding RLC/RLSD to the MSC.\n");
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return;
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}
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msc_send_msg(fw, rc, &result, _msg);
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}
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void mtp_link_set_forward_isup(struct mtp_link_set *set, struct msgb *msg, int sls)
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{
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LOGP(DINP, LOGL_ERROR, "ISUP is not handled.\n");
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}
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/*
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* handle local message in close down mode
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*/
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static void handle_local_sccp(struct mtp_link_set *link, struct msgb *inpt, struct sccp_parse_result *result, int sls)
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{
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/* Handle msg with a reject */
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if (inpt->l2h[0] == SCCP_MSG_TYPE_CR) {
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struct sccp_connection_request *cr;
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struct msgb *msg;
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LOGP(DINP, LOGL_NOTICE, "Handling CR localy.\n");
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cr = (struct sccp_connection_request *) inpt->l2h;
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msg = create_sccp_refuse(&cr->source_local_reference);
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if (msg) {
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mtp_link_set_submit_sccp_data(link, sls, msg->l2h, msgb_l2len(msg));
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msgb_free(msg);
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}
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return;
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} else if (inpt->l2h[0] == SCCP_MSG_TYPE_DT1 && result->data_len >= 3) {
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struct active_sccp_con *con;
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struct sccp_data_form1 *form1;
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struct msgb *msg;
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if (inpt->l3h[0] == 0 && inpt->l3h[2] == BSS_MAP_MSG_CLEAR_COMPLETE) {
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LOGP(DINP, LOGL_DEBUG, "Received Clear Complete. Sending Release.\n");
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form1 = (struct sccp_data_form1 *) inpt->l2h;
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llist_for_each_entry(con, &link->fw->sccp_connections, entry) {
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if (memcmp(&form1->destination_local_reference,
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&con->dst_ref, sizeof(con->dst_ref)) == 0) {
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LOGP(DINP, LOGL_DEBUG, "Sending a release request now.\n");
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msg = create_sccp_rlsd(&con->dst_ref, &con->src_ref);
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if (msg) {
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mtp_link_set_submit_sccp_data(link, con->sls, msg->l2h, msgb_l2len(msg));
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msgb_free(msg);
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}
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return;
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}
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}
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LOGP(DINP, LOGL_ERROR, "Could not find connection for the Clear Command.\n");
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}
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} else if (inpt->l2h[0] == SCCP_MSG_TYPE_UDT && result->data_len >= 3) {
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if (inpt->l3h[0] == 0 && inpt->l3h[2] == BSS_MAP_MSG_RESET_ACKNOWLEDGE) {
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LOGP(DINP, LOGL_NOTICE, "Reset ACK. Connecting to the MSC again.\n");
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bsc_resources_released(link->fw);
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return;
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}
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}
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/* Update the state, maybe the connection was released? */
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update_con_state(link->fw, 0, result, inpt, 0, sls);
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if (llist_empty(&link->fw->sccp_connections))
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bsc_resources_released(link->fw);
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return;
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}
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static void clear_connections(struct msc_connection *fw)
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{
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struct active_sccp_con *tmp, *con;
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llist_for_each_entry_safe(con, tmp, &fw->sccp_connections, entry) {
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free_con(con);
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}
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link_clear_all(fw->target_link);
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}
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void bsc_resources_released(struct msc_connection *fw)
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{
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bsc_del_timer(&fw->reset_timeout);
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}
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static void bsc_reset_timeout(void *_data)
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{
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struct msgb *msg;
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struct msc_connection *fw = _data;
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/* no reset */
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if (fw->reset_count > 0) {
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LOGP(DINP, LOGL_ERROR, "The BSC did not answer the GSM08.08 reset. Restart MTP\n");
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mtp_link_set_stop(fw->target_link);
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clear_connections(fw);
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link_reset_all(fw->target_link);
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bsc_resources_released(fw);
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return;
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}
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msg = create_reset();
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if (!msg) {
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bsc_schedule_timer(&fw->reset_timeout, 10, 0);
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return;
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}
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++fw->reset_count;
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mtp_link_set_submit_sccp_data(fw->target_link, -1, msg->l2h, msgb_l2len(msg));
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msgb_free(msg);
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bsc_schedule_timer(&fw->reset_timeout, 20, 0);
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}
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/*
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* We have lost the connection to the MSC. This is tough. We
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* can not just bring down the MTP link as this will disable
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* the BTS radio. We will have to do the following:
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*
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* 1.) Bring down all open SCCP connections. As this will close
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* all radio resources
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* 2.) Bring down all MGCP endpoints
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* 3.) Clear the connection data.
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*
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* To make things worse we need to buffer the BSC messages... atfer
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* everything has been sent we will try to connect to the MSC again.
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*
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* We will have to veriy that all connections are closed properly..
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* this means we need to parse response message. In the case the
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* MTP link is going down while we are sending. We will simply
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* reconnect to the MSC.
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*/
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void release_bsc_resources(struct msc_connection *fw)
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{
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struct active_sccp_con *tmp;
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struct active_sccp_con *con;
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bsc_del_timer(&fw->reset_timeout);
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/* 2. clear the MGCP endpoints */
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mgcp_reset(fw);
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/* 1. send BSSMAP Cleanup.. if we have any connection */
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llist_for_each_entry_safe(con, tmp, &fw->sccp_connections, entry) {
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if (!con->has_dst_ref) {
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free_con(con);
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continue;
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}
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struct msgb *msg = create_clear_command(&con->src_ref);
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if (!msg)
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continue;
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/* wait for the clear commands */
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mtp_link_set_submit_sccp_data(fw->target_link, con->sls, msg->l2h, msgb_l2len(msg));
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msgb_free(msg);
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}
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if (llist_empty(&fw->sccp_connections)) {
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bsc_resources_released(fw);
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} else {
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/* Send a reset in 20 seconds if we fail to bring everything down */
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fw->reset_timeout.cb = bsc_reset_timeout;
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fw->reset_timeout.data = fw;
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fw->reset_count = 0;
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bsc_schedule_timer(&fw->reset_timeout, 10, 0);
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}
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}
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void mtp_linkset_down(struct mtp_link_set *set)
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{
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set->available = 0;
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mtp_link_set_stop(set);
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clear_connections(set->fw);
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mgcp_reset(set->fw);
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/* If we have an A link send a reset to the MSC */
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msc_send_reset(set->fw);
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}
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void mtp_linkset_up(struct mtp_link_set *set)
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{
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set->available = 1;
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/* we have not gone through link down */
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if (set->fw->msc_link_down) {
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clear_connections(set->fw);
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bsc_resources_released(set->fw);
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}
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mtp_link_set_reset(set);
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}
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/**
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* update the connection state and helpers below
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*/
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static void send_rlc_to_bsc(struct msc_connection *fw,
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unsigned int sls, struct sccp_source_reference *src,
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struct sccp_source_reference *dst)
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{
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struct msgb *msg;
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msg = create_sccp_rlc(src, dst);
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if (!msg)
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return;
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mtp_link_set_submit_sccp_data(fw->target_link, sls, msg->l2h, msgb_l2len(msg));
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msgb_free(msg);
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}
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static void handle_rlsd(struct msc_connection *fw, struct sccp_connection_released *rlsd, int from_msc)
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{
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struct active_sccp_con *con;
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if (from_msc) {
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/* search for a connection, reverse src/dest for MSC */
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con = find_con_by_src_dest_ref(fw, &rlsd->destination_local_reference,
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&rlsd->source_local_reference);
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if (con) {
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LOGP(DINP, LOGL_DEBUG, "RLSD conn still alive: local: 0x%x remote: 0x%x\n",
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sccp_src_ref_to_int(&con->src_ref),
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sccp_src_ref_to_int(&con->dst_ref));
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con->released_from_msc = 1;
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} else {
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/* send RLC */
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LOGP(DINP, LOGL_DEBUG, "Sending RLC for MSC: src: 0x%x dst: 0x%x\n",
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sccp_src_ref_to_int(&rlsd->destination_local_reference),
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sccp_src_ref_to_int(&rlsd->source_local_reference));
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msc_send_rlc(fw, &rlsd->destination_local_reference,
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&rlsd->source_local_reference);
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}
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} else {
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unsigned int sls = -1;
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con = find_con_by_src_dest_ref(fw, &rlsd->source_local_reference,
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&rlsd->destination_local_reference);
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if (con) {
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LOGP(DINP, LOGL_DEBUG, "Timeout on BSC. Sending RLC. src: 0x%x\n",
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sccp_src_ref_to_int(&rlsd->source_local_reference));
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if (con->released_from_msc)
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msc_send_rlc(fw, &con->src_ref, &con->dst_ref);
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sls = con->sls;
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free_con(con);
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} else {
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LOGP(DINP, LOGL_ERROR, "Timeout on BSC for unknown connection. src: 0x%x\n",
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sccp_src_ref_to_int(&rlsd->source_local_reference));
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}
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/* now send a rlc back to the BSC */
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send_rlc_to_bsc(fw, sls, &rlsd->destination_local_reference, &rlsd->source_local_reference);
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}
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}
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/**
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* Update connection state and also send message.....
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*
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* RLSD from MSC:
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* 1.) We don't find the entry in this case we will send a
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* forged RLC to the MSC and we are done.
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* 2.) We find an entry in this we will need to register that
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* we need to send a RLC and we are done for now.
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* RLSD from BSC:
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* 1.) This is an error we are ignoring for now.
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* RLC from BSC:
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* 1.) We are destroying the connection, we might send a RLC to
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* the MSC if we are waiting for one.
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*/
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void update_con_state(struct msc_connection *fw, int rc, struct sccp_parse_result *res, struct msgb *msg, int from_msc, int sls)
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{
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struct active_sccp_con *con;
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struct sccp_connection_request *cr;
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struct sccp_connection_confirm *cc;
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struct sccp_connection_release_complete *rlc;
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struct sccp_connection_refused *cref;
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/* was the header okay? */
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if (rc < 0)
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return;
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/* the header was size checked */
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switch (msg->l2h[0]) {
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case SCCP_MSG_TYPE_CR:
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if (from_msc) {
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LOGP(DMSC, LOGL_ERROR, "CR from MSC is not handled.\n");
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return;
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}
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cr = (struct sccp_connection_request *) msg->l2h;
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con = find_con_by_src_ref(fw, &cr->source_local_reference);
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if (con) {
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LOGP(DINP, LOGL_ERROR, "Duplicate SRC reference for: 0x%x. Reusing\n",
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sccp_src_ref_to_int(&con->src_ref));
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free_con(con);
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}
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con = talloc_zero(NULL, struct active_sccp_con);
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if (!con) {
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LOGP(DINP, LOGL_ERROR, "Failed to allocate\n");
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return;
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}
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con->src_ref = cr->source_local_reference;
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con->sls = sls;
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con->link = fw->target_link;
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llist_add_tail(&con->entry, &fw->sccp_connections);
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LOGP(DINP, LOGL_DEBUG, "Adding CR: local ref: 0x%x\n", sccp_src_ref_to_int(&con->src_ref));
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break;
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case SCCP_MSG_TYPE_CC:
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if (!from_msc) {
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LOGP(DINP, LOGL_ERROR, "CC from BSC is not handled.\n");
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return;
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}
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cc = (struct sccp_connection_confirm *) msg->l2h;
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con = find_con_by_src_ref(fw, &cc->destination_local_reference);
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if (con) {
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con->dst_ref = cc->source_local_reference;
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con->has_dst_ref = 1;
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LOGP(DINP, LOGL_DEBUG, "Updating CC: local: 0x%x remote: 0x%x\n",
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sccp_src_ref_to_int(&con->src_ref), sccp_src_ref_to_int(&con->dst_ref));
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return;
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}
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LOGP(DINP, LOGL_ERROR, "CCed connection can not be found: 0x%x\n",
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sccp_src_ref_to_int(&cc->destination_local_reference));
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break;
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case SCCP_MSG_TYPE_CREF:
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if (!from_msc) {
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LOGP(DINP, LOGL_ERROR, "CREF from BSC is not handled.\n");
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return;
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}
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cref = (struct sccp_connection_refused *) msg->l2h;
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con = find_con_by_src_ref(fw, &cref->destination_local_reference);
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if (con) {
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LOGP(DINP, LOGL_DEBUG, "Releasing local: 0x%x\n", sccp_src_ref_to_int(&con->src_ref));
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free_con(con);
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return;
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}
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LOGP(DINP, LOGL_ERROR, "CREF from BSC is not handled.\n");
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break;
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case SCCP_MSG_TYPE_RLSD:
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handle_rlsd(fw, (struct sccp_connection_released *) msg->l2h, from_msc);
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break;
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case SCCP_MSG_TYPE_RLC:
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if (from_msc) {
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LOGP(DINP, LOGL_ERROR, "RLC from MSC is wrong.\n");
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return;
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}
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rlc = (struct sccp_connection_release_complete *) msg->l2h;
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con = find_con_by_src_dest_ref(fw, &rlc->source_local_reference,
|
|
&rlc->destination_local_reference);
|
|
if (con) {
|
|
LOGP(DINP, LOGL_DEBUG, "Releasing local: 0x%x\n", sccp_src_ref_to_int(&con->src_ref));
|
|
if (con->released_from_msc)
|
|
msc_send_rlc(fw, &con->src_ref, &con->dst_ref);
|
|
free_con(con);
|
|
return;
|
|
}
|
|
|
|
LOGP(DINP, LOGL_ERROR, "RLC can not be found. 0x%x 0x%x\n",
|
|
sccp_src_ref_to_int(&rlc->source_local_reference),
|
|
sccp_src_ref_to_int(&rlc->destination_local_reference));
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void send_local_rlsd_for_con(void *data)
|
|
{
|
|
struct msgb *rlsd;
|
|
struct active_sccp_con *con = (struct active_sccp_con *) data;
|
|
|
|
/* try again in three seconds */
|
|
con->rlc_timeout.data = con;
|
|
con->rlc_timeout.cb = send_local_rlsd_for_con;
|
|
bsc_schedule_timer(&con->rlc_timeout, 3, 0);
|
|
|
|
/* we send this to the BSC so we need to switch src and dest */
|
|
rlsd = create_sccp_rlsd(&con->dst_ref, &con->src_ref);
|
|
if (!rlsd)
|
|
return;
|
|
|
|
++con->rls_tries;
|
|
LOGP(DINP, LOGL_DEBUG, "Sending RLSD for 0x%x the %d time.\n",
|
|
sccp_src_ref_to_int(&con->src_ref), con->rls_tries);
|
|
mtp_link_set_submit_sccp_data(con->link, con->sls, rlsd->l2h, msgb_l2len(rlsd));
|
|
msgb_free(rlsd);
|
|
}
|
|
|
|
static void send_local_rlsd(struct mtp_link_set *link, struct sccp_parse_result *res)
|
|
{
|
|
struct active_sccp_con *con;
|
|
|
|
LOGP(DINP, LOGL_DEBUG, "Received GSM Clear Complete. Sending RLSD locally.\n");
|
|
|
|
con = find_con_by_dest_ref(link->fw, res->destination_local_reference);
|
|
if (!con)
|
|
return;
|
|
con->rls_tries = 0;
|
|
send_local_rlsd_for_con(con);
|
|
}
|
|
|
|
static void send_reset_ack(struct mtp_link_set *link, int sls)
|
|
{
|
|
static const uint8_t reset_ack[] = {
|
|
0x09, 0x00, 0x03, 0x05, 0x7, 0x02, 0x42, 0xfe,
|
|
0x02, 0x42, 0xfe, 0x03,
|
|
0x00, 0x01, 0x31
|
|
};
|
|
|
|
mtp_link_set_submit_sccp_data(link, sls, reset_ack, sizeof(reset_ack));
|
|
}
|