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/* SMLC Lb connection implementation */
/*
* (C) 2020 by sysmocom s.m.f.c. <info@sysmocom.de>
* All Rights Reserved
*
* Author: Neels Hofmeyr
*
* 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 <errno.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/fsm.h>
#include <osmocom/core/signal.h>
#include <osmocom/gsm/bssmap_le.h>
#include <osmocom/smlc/debug.h>
#include <osmocom/smlc/smlc_data.h>
#include <osmocom/smlc/sccp_lb_inst.h>
#include <osmocom/smlc/lb_peer.h>
#include <osmocom/smlc/lb_conn.h>
#include <osmocom/smlc/smlc_loc_req.h>
static int lb_conn_use_cb(struct osmo_use_count_entry *e, int32_t old_use_count, const char *file, int line)
{
struct lb_conn *lb_conn = e->use_count->talloc_object;
int32_t total;
int level;
if (!e->use)
return -EINVAL;
total = osmo_use_count_total(&lb_conn->use_count);
if (total == 0
|| (total == 1 && old_use_count == 0 && e->count == 1))
level = LOGL_INFO;
else
level = LOGL_DEBUG;
LOG_LB_CONN_SL(lb_conn, DREF, level, file, line, "%s %s: now used by %s\n",
(e->count - old_use_count) > 0? "+" : "-", e->use,
osmo_use_count_to_str_c(OTC_SELECT, &lb_conn->use_count));
if (e->count < 0)
return -ERANGE;
if (total == 0)
lb_conn_close(lb_conn);
return 0;
}
static struct lb_conn *lb_conn_alloc(struct lb_peer *lb_peer, uint32_t sccp_conn_id, const char *use_token)
{
struct lb_conn *lb_conn;
lb_conn = talloc(lb_peer, struct lb_conn);
OSMO_ASSERT(lb_conn);
*lb_conn = (struct lb_conn){
.lb_peer = lb_peer,
.sccp_conn_id = sccp_conn_id,
.use_count = {
.talloc_object = lb_conn,
.use_cb = lb_conn_use_cb,
},
};
llist_add(&lb_conn->entry, &lb_peer->sli->lb_conns);
lb_conn_get(lb_conn, use_token);
return lb_conn;
}
struct lb_conn *lb_conn_create_incoming(struct lb_peer *lb_peer, uint32_t sccp_conn_id, const char *use_token)
{
LOG_LB_PEER(lb_peer, LOGL_DEBUG, "Incoming lb_conn id: %u\n", sccp_conn_id);
return lb_conn_alloc(lb_peer, sccp_conn_id, use_token);
}
struct lb_conn *lb_conn_create_outgoing(struct lb_peer *lb_peer, const char *use_token)
{
int new_conn_id = sccp_lb_inst_next_conn_id();
if (new_conn_id < 0)
return NULL;
LOG_LB_PEER(lb_peer, LOGL_DEBUG, "Outgoing lb_conn id: %u\n", new_conn_id);
return lb_conn_alloc(lb_peer, new_conn_id, use_token);
}
struct lb_conn *lb_conn_find_by_smlc_subscr(struct smlc_subscr *smlc_subscr, const char *use_token)
{
struct lb_conn *lb_conn;
llist_for_each_entry(lb_conn, &g_smlc->lb->lb_conns, entry) {
if (lb_conn->smlc_subscr == smlc_subscr) {
lb_conn_get(lb_conn, use_token);
return lb_conn;
}
}
return NULL;
}
int lb_conn_down_l2_co(struct lb_conn *lb_conn, struct msgb *l3, bool initial)
{
struct lb_peer_ev_ctx co = {
.conn_id = lb_conn->sccp_conn_id,
.lb_conn = lb_conn,
.msg = l3,
};
if (!lb_conn->lb_peer)
return -EIO;
return osmo_fsm_inst_dispatch(lb_conn->lb_peer->fi,
initial ? LB_PEER_EV_MSG_DOWN_CO_INITIAL : LB_PEER_EV_MSG_DOWN_CO,
&co);
}
int lb_conn_rx(struct lb_conn *lb_conn, struct msgb *msg, bool initial)
{
struct bssap_le_pdu bssap_le;
struct osmo_bssap_le_err *err;
if (osmo_bssap_le_dec(&bssap_le, &err, msg, msg)) {
LOG_LB_CONN(lb_conn, LOGL_ERROR, "Rx BSSAP-LE with error: %s\n", err->logmsg);
return -EINVAL;
}
return smlc_loc_req_rx_bssap_le(lb_conn, &bssap_le);
}
int lb_conn_send_bssmap_le(struct lb_conn *lb_conn, const struct bssmap_le_pdu *bssmap_le)
{
struct msgb *msg;
int rc;
struct bssap_le_pdu bssap_le = {
.discr = BSSAP_LE_MSG_DISCR_BSSMAP_LE,
.bssmap_le = *bssmap_le,
};
msg = osmo_bssap_le_enc(&bssap_le);
if (!msg) {
LOG_LB_CONN(lb_conn, LOGL_ERROR, "Unable to encode %s\n",
osmo_bssap_le_pdu_to_str_c(OTC_SELECT, &bssap_le));
return -EINVAL;
}
rc = lb_conn_down_l2_co(lb_conn, msg, false);
msgb_free(msg);
if (rc)
LOG_LB_CONN(lb_conn, LOGL_ERROR, "Unable to send %s\n",
osmo_bssap_le_pdu_to_str_c(OTC_SELECT, &bssap_le));
return rc;
}
/* Regularly close the lb_conn */
void lb_conn_close(struct lb_conn *lb_conn)
{
if (!lb_conn)
return;
if (lb_conn->closing)
return;
lb_conn->closing = true;
LOG_LB_PEER(lb_conn->lb_peer, LOGL_DEBUG, "Closing lb_conn\n");
if (lb_conn->lb_peer) {
/* Todo: pass a useful SCCP cause? */
sccp_lb_disconnect(lb_conn->lb_peer->sli, lb_conn->sccp_conn_id, 0);
lb_conn->lb_peer = NULL;
}
if (lb_conn->smlc_loc_req)
osmo_fsm_inst_term(lb_conn->smlc_loc_req->fi, OSMO_FSM_TERM_REGULAR, NULL);
if (lb_conn->smlc_subscr)
smlc_subscr_put(lb_conn->smlc_subscr, SMLC_SUBSCR_USE_LB_CONN);
llist_del(&lb_conn->entry);
talloc_free(lb_conn);
}
/* Same as lb_conn_close() but without sending any SCCP messages (e.g. after RESET) */
void lb_conn_discard(struct lb_conn *lb_conn)
{
if (!lb_conn)
return;
/* Make sure to drop dead and don't dispatch things like DISCONNECT requests on SCCP. */
lb_conn->lb_peer = NULL;
lb_conn_close(lb_conn);
}