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/* (C) 2017 by sysmocom s.f.m.c. GmbH
* All Rights Reserved
*
* Author: Philipp Maier
*
* 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/core/logging.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/fsm.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <openbsc/debug.h>
#include <openbsc/bsc_msc_data.h>
#include <openbsc/osmo_bsc_sigtran.h>
#define RESET_RESEND_INTERVAL 2 /* sec */
#define RESET_RESEND_TIMER_NO 1234 /* FIXME: dig out the real timer number */
#define BAD_CONNECTION_THRESOLD 3 /* connection failures */
enum fsm_states {
ST_DISC, /* Disconnected from MSC */
ST_CONN, /* We have a confirmed connection to the MSC */
};
static const struct value_string fsm_state_names[] = {
{ST_DISC, "ST_DISC (disconnected)"},
{ST_CONN, "ST_CONN (connected)"},
{0, NULL},
};
enum fsm_evt {
EV_RESET_ACK, /* got reset acknowlegement from the MSC */
EV_N_DISCONNECT, /* lost a connection */
EV_N_CONNECT, /* made a successful connection */
};
static const struct value_string fsm_evt_names[] = {
{EV_RESET_ACK, "EV_RESET_ACK"},
{EV_N_DISCONNECT, "EV_N_DISCONNECT"},
{EV_N_CONNECT, "EV_N_CONNECT"},
{0, NULL},
};
/* Disconnected state */
static void fsm_disc_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct bsc_msc_data *msc = (struct bsc_msc_data *)data;
LOGP(DMSC, LOGL_NOTICE, "fsm-state (msc-reset): %s, fsm-event: %s, MSC No.: %i\n",
get_value_string(fsm_state_names, ST_DISC), get_value_string(fsm_evt_names, event), msc->nr);
msc->msc_con->msc_conn_loss_count = 0;
osmo_fsm_inst_state_chg(fi, ST_CONN, 0, 0);
}
/* Connected state */
static void fsm_conn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct bsc_msc_data *msc = (struct bsc_msc_data *)data;
LOGP(DMSC, LOGL_NOTICE, "fsm-state (msc-reset): %s, fsm-event: %s, MSC No.: %i\n",
get_value_string(fsm_state_names, ST_CONN), get_value_string(fsm_evt_names, event), msc->nr);
OSMO_ASSERT(msc);
switch (event) {
case EV_N_DISCONNECT:
if (msc->msc_con->msc_conn_loss_count >= BAD_CONNECTION_THRESOLD) {
LOGP(DMSC, LOGL_NOTICE, "SIGTRAN connection to MSC No.: %i down, reconnecting...\n", msc->nr);
osmo_fsm_inst_state_chg(fi, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
} else
msc->msc_con->msc_conn_loss_count++;
break;
case EV_N_CONNECT:
msc->msc_con->msc_conn_loss_count = 0;
break;
}
}
/* Timer callback to retransmit the reset signal */
static int fsm_reset_ack_timeout_cb(struct osmo_fsm_inst *fi)
{
struct bsc_msc_data *msc = (struct bsc_msc_data *)fi->priv;
LOGP(DMSC, LOGL_NOTICE, "reset-ack timeout (T%i) in state %s, MSC No.: %i, resending...\n", fi->T,
get_value_string(fsm_state_names, fi->state), msc->nr);
osmo_bsc_sigtran_reset(msc);
osmo_bsc_sigtran_tx_reset(msc);
osmo_fsm_inst_state_chg(fi, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
return 0;
}
static struct osmo_fsm_state fsm_states[] = {
[ST_DISC] = {
.in_event_mask = (1 << EV_RESET_ACK),
.out_state_mask = (1 << ST_DISC) | (1 << ST_CONN),
.name = "DISC",
.action = fsm_disc_cb,
},
[ST_CONN] = {
.in_event_mask = (1 << EV_N_DISCONNECT) | (1 << EV_N_CONNECT),
.out_state_mask = (1 << ST_DISC) | (1 << ST_CONN),
.name = "CONN",
.action = fsm_conn_cb,
},
};
/* State machine definition */
static struct osmo_fsm fsm = {
.name = "FSM RESET",
.states = fsm_states,
.num_states = ARRAY_SIZE(fsm_states),
.log_subsys = DMSC,
.timer_cb = fsm_reset_ack_timeout_cb,
};
/* Create and start state machine which handles the reset/reset-ack procedure */
void start_reset_fsm(struct bsc_msc_data *msc)
{
OSMO_ASSERT(msc);
OSMO_ASSERT(msc->msc_con);
osmo_fsm_register(&fsm);
msc->msc_con->fsm_reset = osmo_fsm_inst_alloc(&fsm, NULL, NULL, LOGL_DEBUG, "FSM RESET INST");
OSMO_ASSERT(msc->msc_con->fsm_reset);
msc->msc_con->fsm_reset->priv = msc;
/* kick off reset-ack sending mechanism */
osmo_fsm_inst_state_chg(msc->msc_con->fsm_reset, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
}
/* Confirm that we sucessfully received a reset acknowlege message */
void reset_ack_confirm(struct bsc_msc_data *msc)
{
OSMO_ASSERT(msc);
OSMO_ASSERT(msc->msc_con);
OSMO_ASSERT(msc->msc_con->fsm_reset);
osmo_fsm_inst_dispatch(msc->msc_con->fsm_reset, EV_RESET_ACK, msc);
}
/* Report a failed connection */
void report_conn_fail(struct bsc_msc_data *msc)
{
OSMO_ASSERT(msc);
OSMO_ASSERT(msc->msc_con);
OSMO_ASSERT(msc->msc_con->fsm_reset);
osmo_fsm_inst_dispatch(msc->msc_con->fsm_reset, EV_N_DISCONNECT, msc);
}
/* Report a successful connection */
void report_conn_success(struct bsc_msc_data *msc)
{
OSMO_ASSERT(msc);
OSMO_ASSERT(msc->msc_con);
OSMO_ASSERT(msc->msc_con->fsm_reset);
osmo_fsm_inst_dispatch(msc->msc_con->fsm_reset, EV_N_CONNECT, msc);
}
/* Check if we have a connection to a specified msc */
bool sccp_conn_ready(struct bsc_msc_data *msc)
{
OSMO_ASSERT(msc);
OSMO_ASSERT(msc->msc_con);
OSMO_ASSERT(msc->msc_con->fsm_reset);
if (msc->msc_con->fsm_reset->state == ST_CONN)
return true;
return false;
}
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