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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 remote end */
ST_CONN, /* We have a confirmed connection */
};
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 remote end */
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 a_reset_ctx *reset = (struct a_reset_ctx *)data;
OSMO_ASSERT(reset);
LOGP(DMSC, LOGL_NOTICE, "(%s) fsm-state (msc-reset): %s, fsm-event: %s\n", reset->name,
get_value_string(fsm_state_names, ST_CONN), get_value_string(fsm_evt_names, event));
reset->conn_loss_counter = 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 a_reset_ctx *reset = (struct a_reset_ctx *)data;
OSMO_ASSERT(reset);
LOGP(DMSC, LOGL_NOTICE, "(%s) fsm-state (msc-reset): %s, fsm-event: %s\n", reset->name,
get_value_string(fsm_state_names, ST_CONN), get_value_string(fsm_evt_names, event));
switch (event) {
case EV_N_DISCONNECT:
if (reset->conn_loss_counter >= BAD_CONNECTION_THRESOLD) {
LOGP(DMSC, LOGL_NOTICE, "(%s) SIGTRAN connection down, reconnecting...\n", reset->name);
osmo_fsm_inst_state_chg(fi, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
} else
reset->conn_loss_counter++;
break;
case EV_N_CONNECT:
reset->conn_loss_counter = 0;
break;
}
}
/* Timer callback to retransmit the reset signal */
static int fsm_reset_ack_timeout_cb(struct osmo_fsm_inst *fi)
{
struct a_reset_ctx *reset = (struct a_reset_ctx *)fi->priv;
LOGP(DMSC, LOGL_NOTICE, "(%s) reset-ack timeout (T%i) in state %s, resending...\n", reset->name, fi->T,
get_value_string(fsm_state_names, fi->state));
reset->cb(reset->priv);
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 */
struct a_reset_ctx *a_reset_alloc(void *ctx, char *name, void *cb, void *priv)
{
OSMO_ASSERT(name);
struct a_reset_ctx *reset;
/* Register the fsm description (if not already done) */
if (osmo_fsm_find_by_name(fsm.name) != &fsm)
osmo_fsm_register(&fsm);
/* Allocate and configure a new fsm instance */
reset = talloc_zero(ctx, struct a_reset_ctx);
OSMO_ASSERT(reset);
reset->priv = priv;
reset->cb = cb;
strncpy(reset->name, name, sizeof(reset->name));
reset->conn_loss_counter = 0;
reset->fsm = osmo_fsm_inst_alloc(&fsm, NULL, NULL, LOGL_DEBUG, "FSM RESET INST");
OSMO_ASSERT(reset->fsm);
reset->fsm->priv = reset;
LOGP(DMSC, LOGL_NOTICE, "(%s) reset handler fsm created.\n", reset->name);
/* kick off reset-ack sending mechanism */
osmo_fsm_inst_state_chg(reset->fsm, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
return reset;
}
/* Tear down state machine */
void a_reset_free(struct a_reset_ctx *reset)
{
OSMO_ASSERT(reset);
OSMO_ASSERT(reset->fsm);
osmo_fsm_inst_free(reset->fsm);
reset->fsm = NULL;
memset(reset, 0, sizeof(*reset));
talloc_free(reset);
LOGP(DMSC, LOGL_NOTICE, "(%s) reset handler fsm destroyed.\n", reset->name);
}
/* Confirm that we sucessfully received a reset acknowlege message */
void a_reset_ack_confirm(struct a_reset_ctx *reset)
{
OSMO_ASSERT(reset);
OSMO_ASSERT(reset->fsm);
osmo_fsm_inst_dispatch(reset->fsm, EV_RESET_ACK, reset);
}
/* Report a failed connection */
void a_reset_conn_fail(struct a_reset_ctx *reset)
{
/* If no reset context is supplied, just drop the info */
if (!reset)
return;
OSMO_ASSERT(reset->fsm);
osmo_fsm_inst_dispatch(reset->fsm, EV_N_DISCONNECT, reset);
}
/* Report a successful connection */
void a_reset_conn_success(struct a_reset_ctx *reset)
{
/* If no reset context is supplied, just drop the info */
if (!reset)
return;
OSMO_ASSERT(reset->fsm);
osmo_fsm_inst_dispatch(reset->fsm, EV_N_CONNECT, reset);
}
/* Check if we have a connection to a specified msc */
bool a_reset_conn_ready(struct a_reset_ctx *reset)
{
/* If no reset context is supplied, we assume that
* the connection can't be ready! */
if (!reset)
return false;
OSMO_ASSERT(reset->fsm);
if (reset->fsm->state == ST_CONN)
return true;
return false;
}
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