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authorPhilipp Maier <pmaier@sysmocom.de>2017-06-06 14:31:36 +0200
committerNeels Hofmeyr <nhofmeyr@sysmocom.de>2017-06-18 17:50:08 +0200
commit8b0d8a97fb5cddb718c0b35af02bbcfe4599bdc5 (patch)
treed81ce0f11db4ae55542fd702132f3b89c4b3cef8 /openbsc/src/osmo-bsc/osmo_bsc_reset.c
parentfabe468dd47ffd72a3ff2b6387422d304b178665 (diff)
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
Diffstat (limited to 'openbsc/src/osmo-bsc/osmo_bsc_reset.c')
-rw-r--r--openbsc/src/osmo-bsc/osmo_bsc_reset.c190
1 files changed, 190 insertions, 0 deletions
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 <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 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;
+}