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Diffstat (limited to 'src/osmo-bsc/a_reset.c')
| -rw-r--r-- | src/osmo-bsc/a_reset.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/src/osmo-bsc/a_reset.c b/src/osmo-bsc/a_reset.c new file mode 100644 index 000000000..b8f8c8cbd --- /dev/null +++ b/src/osmo-bsc/a_reset.c @@ -0,0 +1,205 @@ +/* (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/bsc/debug.h> +#include <osmocom/bsc/bsc_msc_data.h> +#include <osmocom/bsc/osmo_bsc_sigtran.h> + +#define RESET_RESEND_INTERVAL 2 /* sec */ +#define RESET_RESEND_TIMER_NO 4 /* See also 3GPP TS 48.008 Chapter 3.1.4.1.3.1 */ +#define BAD_CONNECTION_THRESOLD 3 /* connection failures */ + +/* Reset context data (callbacks, state machine etc...) */ +struct reset_ctx { + /* Connection failure counter. When this counter + * reaches a certain threshold, the reset procedure + * will be triggered */ + int conn_loss_counter; + + /* Callback function to be called when a connection + * failure is detected and a rest must occur */ + void (*cb)(void *priv); + + /* Privated data for the callback function */ + void *priv; +}; + +enum reset_fsm_states { + ST_DISC, /* Disconnected from remote end */ + ST_CONN, /* We have a confirmed connection */ +}; + +enum reset_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_event_names[] = { + OSMO_VALUE_STRING(EV_RESET_ACK), + OSMO_VALUE_STRING(EV_N_DISCONNECT), + OSMO_VALUE_STRING(EV_N_CONNECT), + {0, NULL} +}; + +/* Disconnected state */ +static void fsm_disc_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data) +{ + struct reset_ctx *reset_ctx = (struct reset_ctx *)fi->priv; + OSMO_ASSERT(reset_ctx); + LOGPFSML(fi, LOGL_NOTICE, "SIGTRAN connection succeded.\n"); + + reset_ctx->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 reset_ctx *reset_ctx = (struct reset_ctx *)fi->priv; + OSMO_ASSERT(reset_ctx); + + switch (event) { + case EV_N_DISCONNECT: + if (reset_ctx->conn_loss_counter >= BAD_CONNECTION_THRESOLD) { + LOGPFSML(fi, LOGL_NOTICE, "SIGTRAN connection down, reconnecting...\n"); + osmo_fsm_inst_state_chg(fi, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO); + } else + reset_ctx->conn_loss_counter++; + break; + case EV_N_CONNECT: + reset_ctx->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 reset_ctx *reset_ctx = (struct reset_ctx *)fi->priv; + OSMO_ASSERT(reset_ctx); + + LOGPFSML(fi, LOGL_NOTICE, "(re)sending BSSMAP RESET message...\n"); + + reset_ctx->cb(reset_ctx->priv); + + osmo_fsm_inst_state_chg(fi, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO); + return 0; +} + +static struct osmo_fsm_state reset_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 = reset_fsm_states, + .num_states = ARRAY_SIZE(reset_fsm_states), + .log_subsys = DMSC, + .timer_cb = fsm_reset_ack_timeout_cb, + .event_names = fsm_event_names, +}; + +/* Create and start state machine which handles the reset/reset-ack procedure */ +struct osmo_fsm_inst *a_reset_alloc(void *ctx, const char *name, void *cb, void *priv) +{ + OSMO_ASSERT(name); + + struct reset_ctx *reset_ctx; + struct osmo_fsm_inst *reset_fsm; + + /* 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_ctx = talloc_zero(ctx, struct reset_ctx); + OSMO_ASSERT(reset_ctx); + reset_ctx->priv = priv; + reset_ctx->cb = cb; + reset_ctx->conn_loss_counter = 0; + reset_fsm = osmo_fsm_inst_alloc(&fsm, ctx, reset_ctx, LOGL_DEBUG, name); + OSMO_ASSERT(reset_fsm); + + /* kick off reset-ack sending mechanism */ + osmo_fsm_inst_state_chg(reset_fsm, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO); + + return reset_fsm; +} + +/* Confirm that we sucessfully received a reset acknowlege message */ +void a_reset_ack_confirm(struct osmo_fsm_inst *reset_fsm) +{ + OSMO_ASSERT(reset_fsm); + osmo_fsm_inst_dispatch(reset_fsm, EV_RESET_ACK, NULL); +} + +/* Report a failed connection */ +void a_reset_conn_fail(struct osmo_fsm_inst *reset_fsm) +{ + /* If no reset context is supplied, just drop the info */ + if (!reset_fsm) + return; + + osmo_fsm_inst_dispatch(reset_fsm, EV_N_DISCONNECT, NULL); +} + +/* Report a successful connection */ +void a_reset_conn_success(struct osmo_fsm_inst *reset_fsm) +{ + /* If no reset context is supplied, just drop the info */ + if (!reset_fsm) + return; + + osmo_fsm_inst_dispatch(reset_fsm, EV_N_CONNECT, NULL); +} + +/* Check if we have a connection to a specified msc */ +bool a_reset_conn_ready(struct osmo_fsm_inst *reset_fsm) +{ + /* If no reset context is supplied, we assume that + * the connection can't be ready! */ + if (!reset_fsm) + return false; + + if (reset_fsm->state == ST_CONN) + return true; + + return false; +} |