From 8b0d8a97fb5cddb718c0b35af02bbcfe4599bdc5 Mon Sep 17 00:00:00 2001 From: Philipp Maier Date: Tue, 6 Jun 2017 14:31:36 +0200 Subject: osmo-bsc: Handle RESET/RESET-ACK properly Improve the way the BSC executes its RESET/RESET-ACK sequence. Currently only a simple bool variable serves as a state holder. We set this variable to true when we receive the RESET-ACK message. Unfortunately no further checking is done. This patch replaces the old mechanism with a more elaborated implementation which also detects a loss of the connection and makes sure to reconnect properly afterwards. Also the all open connections are closed on connection loss --- openbsc/src/osmo-bsc/osmo_bsc_reset.c | 190 ++++++++++++++++++++++++++++++++++ 1 file changed, 190 insertions(+) create mode 100644 openbsc/src/osmo-bsc/osmo_bsc_reset.c (limited to 'openbsc/src/osmo-bsc/osmo_bsc_reset.c') diff --git a/openbsc/src/osmo-bsc/osmo_bsc_reset.c b/openbsc/src/osmo-bsc/osmo_bsc_reset.c new file mode 100644 index 000000000..0baf08089 --- /dev/null +++ b/openbsc/src/osmo-bsc/osmo_bsc_reset.c @@ -0,0 +1,190 @@ +/* (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 . + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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; +} -- cgit v1.2.3