Implement AoIP, port to M3UA SIGTRAN (large addition and refactoring)

This was originally a long series of commits converging to the final result
seen in this patch. It does not make much sense to review the smaller steps'
trial and error, we need to review this entire change as a whole.

Implement AoIP in osmo-msc and osmo-bsc.

Change over to the new libosmo-sigtran API with support for proper
SCCP/M3UA/SCTP stacking, as mandated by 3GPP specifications for the IuCS and
IuPS interfaces.

From here on, a separate osmo-stp process is required for SCCP routing between
OsmoBSC / OsmoHNBGW <-> OsmoMSC / OsmoSGSN

jenkins.sh: build from libosmo-sccp and osmo-iuh master branches now for new
M3UA SIGTRAN.

Patch-by: pmaier, nhofmeyr, laforge
Change-Id: I5ae4e05ee7c57cad341ea5e86af37c1f6b0ffa77

1 files changed, 190 insertions, 0 deletions

diff --git a/src/osmo-bsc/osmo_bsc_reset.c b/src/osmo-bsc/osmo_bsc_reset.c
new file mode 100644
index 000000000..0baf08089
--- /dev/null
+++ b/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;
+}