151 lines
4.3 KiB
C
151 lines
4.3 KiB
C
/* (C) 2017 by sysmocom s.f.m.c. GmbH
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* All Rights Reserved
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*
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* Author: Philipp Maier
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <osmocom/core/logging.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/core/timer.h>
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#include <osmocom/core/fsm.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <osmocom/msc/debug.h>
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#include <osmocom/msc/a_reset.h>
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#include <osmocom/msc/msc_common.h>
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#define RESET_RESEND_INTERVAL 2 /* sec */
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#define RESET_RESEND_TIMER_NO 16 /* See also 3GPP TS 48.008 Chapter 3.1.4.1.3.2 */
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enum reset_fsm_states {
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ST_DISC, /* Disconnected from remote end */
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ST_CONN, /* We have a confirmed connection */
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};
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enum reset_fsm_evt {
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EV_CONN_ACK, /* Received either BSSMAP RESET or BSSMAP RESET
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* ACK from the remote end */
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};
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/* Reset context data (callbacks, state machine etc...) */
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struct reset_ctx {
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/* Callback function to be called when a connection
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* failure is detected and a rest must occur */
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void (*cb)(void *priv);
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/* Privated data for the callback function */
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void *priv;
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};
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static const struct value_string fsm_event_names[] = {
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OSMO_VALUE_STRING(EV_CONN_ACK),
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{0, NULL}
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};
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/* Disconnected state */
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static void fsm_disc_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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osmo_fsm_inst_state_chg(fi, ST_CONN, 0, 0);
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}
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/* Timer callback to retransmit the reset signal */
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static int fsm_reset_ack_timeout_cb(struct osmo_fsm_inst *fi)
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{
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struct reset_ctx *reset_ctx = (struct reset_ctx *)fi->priv;
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LOGPFSML(fi, LOGL_NOTICE, "(re)sending BSSMAP RESET message...\n");
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reset_ctx->cb(reset_ctx->priv);
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osmo_fsm_inst_state_chg(fi, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
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return 0;
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}
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static struct osmo_fsm_state reset_fsm_states[] = {
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[ST_DISC] = {
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.in_event_mask = (1 << EV_CONN_ACK),
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.out_state_mask = (1 << ST_CONN) | (1 << ST_DISC),
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.name = "DISC",
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.action = fsm_disc_cb,
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},
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[ST_CONN] = {
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.in_event_mask = (1 << EV_CONN_ACK),
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.name = "CONN",
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},
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};
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/* State machine definition */
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static struct osmo_fsm fsm = {
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.name = "A-RESET",
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.states = reset_fsm_states,
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.num_states = ARRAY_SIZE(reset_fsm_states),
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.log_subsys = DMSC,
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.timer_cb = fsm_reset_ack_timeout_cb,
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.event_names = fsm_event_names,
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};
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/* Create and start state machine which handles the reset/reset-ack procedure */
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struct osmo_fsm_inst *a_reset_alloc(void *ctx, const char *name, void *cb,
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void *priv, bool already_connected)
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{
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OSMO_ASSERT(name);
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struct reset_ctx *reset_ctx;
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struct osmo_fsm_inst *reset_fsm;
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/* Register the fsm description (if not already done) */
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if (osmo_fsm_find_by_name(fsm.name) != &fsm)
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osmo_fsm_register(&fsm);
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/* Allocate and configure a new fsm instance */
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reset_ctx = talloc_zero(ctx, struct reset_ctx);
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OSMO_ASSERT(reset_ctx);
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reset_ctx->priv = priv;
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reset_ctx->cb = cb;
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reset_fsm = osmo_fsm_inst_alloc(&fsm, ctx, reset_ctx, LOGL_DEBUG, name);
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OSMO_ASSERT(reset_fsm);
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if (already_connected)
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osmo_fsm_inst_state_chg(reset_fsm, ST_CONN, 0, 0);
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else {
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/* kick off reset-ack sending mechanism */
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osmo_fsm_inst_state_chg(reset_fsm, ST_DISC, RESET_RESEND_INTERVAL,
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RESET_RESEND_TIMER_NO);
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}
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return reset_fsm;
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}
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/* Confirm that we sucessfully received a reset acknowlege message */
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void a_reset_ack_confirm(struct osmo_fsm_inst *reset_fsm)
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{
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OSMO_ASSERT(reset_fsm);
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osmo_fsm_inst_dispatch(reset_fsm, EV_CONN_ACK, NULL);
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}
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/* Check if we have a connection to a specified msc */
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bool a_reset_conn_ready(struct osmo_fsm_inst *reset_fsm)
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{
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/* If no reset context is supplied, we assume that
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* the connection can't be ready! */
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if (!reset_fsm)
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return false;
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if (reset_fsm->state == ST_CONN)
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return true;
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return false;
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}
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