| /* (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 <osmocom/msc/debug.h> |
| #include <osmocom/msc/bsc_msc_data.h> |
| #include <osmocom/msc/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 = "A-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(const void *ctx, const 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, NULL); |
| 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; |
| } |