osmo-bsc/src/osmo-bsc/bsc_sccp.c

65 lines
2.0 KiB
C

/* Generic SCCP handling across all OsmoBSC users */
/*
* (C) 2020 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
*
* All Rights Reserved
*
* Author: Neels Hofmeyr <neels@hofmeyr.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <osmocom/bsc/gsm_data.h>
#include <osmocom/bsc/bsc_msc_data.h>
#include <osmocom/bsc/lb.h>
/* We need an unused SCCP conn_id across all SCCP users. */
int bsc_sccp_inst_next_conn_id(struct osmo_sccp_instance *sccp)
{
static uint32_t next_id = 1;
int i;
/* This looks really suboptimal, but in most cases the static next_id should indicate exactly the next unused
* conn_id, and we only iterate all conns once to make super sure that it is not already in use. */
for (i = 0; i < 0xFFFFFF; i++) {
struct gsm_subscriber_connection *conn;
uint32_t conn_id = next_id;
bool conn_id_already_used = false;
next_id = (next_id + 1) & 0xffffff;
llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry) {
if (conn->sccp.msc && conn->sccp.msc->a.sccp == sccp) {
if (conn_id == conn->sccp.conn_id) {
conn_id_already_used = true;
break;
}
}
if (bsc_gsmnet->smlc->sccp == sccp
&& conn->lcs.lb.state != SUBSCR_SCCP_ST_NONE) {
if (conn_id == conn->lcs.lb.conn_id) {
conn_id_already_used = true;
break;
}
}
}
if (!conn_id_already_used)
return conn_id;
}
return -1;
}