re-structure the OpenBSC directory layout

The new structure divides the code into a number of libraries
for the BSC core functionality, MSC core functionality, Abis transport,
TRAU and other bits.

This doesn't introduce any functional code change but simply moves
around files and alters Makefile.am accordingly.

Next step would be to disentangle a lot of the inter-library
dependencies and make the individual bits of code more independent.

1 files changed, 368 insertions, 0 deletions

diff --git a/openbsc/src/osmo-bsc/osmo_bsc_msc.c b/openbsc/src/osmo-bsc/osmo_bsc_msc.c
new file mode 100644
index 000000000..2e8cf0579
--- /dev/null
+++ b/openbsc/src/osmo-bsc/osmo_bsc_msc.c
@@ -0,0 +1,368 @@
+/*
+ * Handle the connection to the MSC. This include ping/timeout/reconnect
+ * (C) 2008-2009 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2009-2010 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009-2010 by On-Waves
+ * All Rights Reserved
+ *
+ * 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 <openbsc/bsc_nat.h>
+#include <openbsc/debug.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/ipaccess.h>
+#include <openbsc/osmo_msc_data.h>
+#include <openbsc/signal.h>
+
+#include <osmocore/gsm0808.h>
+
+#include <osmocom/sccp/sccp.h>
+
+#include <sys/socket.h>
+#include <netinet/tcp.h>
+#include <unistd.h>
+
+
+static void initialize_if_needed(struct bsc_msc_connection *conn);
+static void send_id_get_response(struct osmo_msc_data *data, int fd);
+static void send_ping(struct osmo_msc_data *data);
+
+/*
+ * MGCP forwarding code
+ */
+static int mgcp_do_read(struct bsc_fd *fd)
+{
+	struct osmo_msc_data *data = (struct osmo_msc_data *) fd->data;
+	struct msgb *mgcp;
+	int ret;
+
+	mgcp = msgb_alloc_headroom(4096, 128, "mgcp_from_gw");
+	if (!mgcp) {
+		LOGP(DMGCP, LOGL_ERROR, "Failed to allocate MGCP message.\n");
+		return -1;
+	}
+
+	ret = read(fd->fd, mgcp->data, 4096 - 128);
+	if (ret <= 0) {
+		LOGP(DMGCP, LOGL_ERROR, "Failed to read: %d/%s\n", errno, strerror(errno));
+		msgb_free(mgcp);
+		return -1;
+	} else if (ret > 4096 - 128) {
+		LOGP(DMGCP, LOGL_ERROR, "Too much data: %d\n", ret);
+		msgb_free(mgcp);
+		return -1;
+        }
+
+	mgcp->l2h = msgb_put(mgcp, ret);
+	msc_queue_write(data->msc_con, mgcp, IPAC_PROTO_MGCP_OLD);
+	return 0;
+}
+
+static int mgcp_do_write(struct bsc_fd *fd, struct msgb *msg)
+{
+	int ret;
+
+	LOGP(DMGCP, LOGL_DEBUG, "Sending msg to MGCP GW size: %u\n", msg->len);
+
+	ret = write(fd->fd, msg->data, msg->len);
+	if (ret != msg->len)
+		LOGP(DMGCP, LOGL_ERROR, "Failed to forward message to MGCP GW (%s).\n", strerror(errno));
+
+	return ret;
+}
+
+static void mgcp_forward(struct osmo_msc_data *data, struct msgb *msg)
+{
+	struct msgb *mgcp;
+
+	if (msgb_l2len(msg) > 4096) {
+		LOGP(DMGCP, LOGL_ERROR, "Can not forward too big message.\n");
+		return;
+	}
+
+	mgcp = msgb_alloc(4096, "mgcp_to_gw");
+	if (!mgcp) {
+		LOGP(DMGCP, LOGL_ERROR, "Failed to send message.\n");
+		return;
+	}
+
+	msgb_put(mgcp, msgb_l2len(msg));
+	memcpy(mgcp->data, msg->l2h, mgcp->len);
+	if (write_queue_enqueue(&data->mgcp_agent, mgcp) != 0) {
+		LOGP(DMGCP, LOGL_FATAL, "Could not queue message to MGCP GW.\n");
+		msgb_free(mgcp);
+	}
+}
+
+static int mgcp_create_port(struct osmo_msc_data *data)
+{
+	int on;
+	struct sockaddr_in addr;
+
+	data->mgcp_agent.bfd.fd = socket(AF_INET, SOCK_DGRAM, 0);
+	if (data->mgcp_agent.bfd.fd < 0) {
+		LOGP(DMGCP, LOGL_FATAL, "Failed to create UDP socket errno: %d\n", errno);
+		return -1;
+	}
+
+	on = 1;
+	setsockopt(data->mgcp_agent.bfd.fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+
+	/* try to bind the socket */
+	memset(&addr, 0, sizeof(addr));
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+	addr.sin_port = 0;
+
+	if (bind(data->mgcp_agent.bfd.fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		LOGP(DMGCP, LOGL_FATAL, "Failed to bind to any port.\n");
+		close(data->mgcp_agent.bfd.fd);
+		data->mgcp_agent.bfd.fd = -1;
+		return -1;
+	}
+
+	/* connect to the remote */
+	addr.sin_port = htons(2427);
+	if (connect(data->mgcp_agent.bfd.fd, (struct sockaddr *) & addr, sizeof(addr)) < 0) {
+		LOGP(DMGCP, LOGL_FATAL, "Failed to connect to local MGCP GW. %s\n", strerror(errno));
+		close(data->mgcp_agent.bfd.fd);
+		data->mgcp_agent.bfd.fd = -1;
+		return -1;
+	}
+
+	write_queue_init(&data->mgcp_agent, 10);
+	data->mgcp_agent.bfd.when = BSC_FD_READ;
+	data->mgcp_agent.bfd.data = data;
+	data->mgcp_agent.read_cb = mgcp_do_read;
+	data->mgcp_agent.write_cb = mgcp_do_write;
+
+	if (bsc_register_fd(&data->mgcp_agent.bfd) != 0) {
+		LOGP(DMGCP, LOGL_FATAL, "Failed to register BFD\n");
+		close(data->mgcp_agent.bfd.fd);
+		data->mgcp_agent.bfd.fd = -1;
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Send data to the network
+ */
+int msc_queue_write(struct bsc_msc_connection *conn, struct msgb *msg, int proto)
+{
+	ipaccess_prepend_header(msg, proto);
+	if (write_queue_enqueue(&conn->write_queue, msg) != 0) {
+		LOGP(DMSC, LOGL_FATAL, "Failed to queue IPA/%d\n", proto);
+		msgb_free(msg);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int msc_alink_do_write(struct bsc_fd *fd, struct msgb *msg)
+{
+	int ret;
+
+	LOGP(DMSC, LOGL_DEBUG, "Sending SCCP to MSC: %u\n", msgb_l2len(msg));
+	LOGP(DMI, LOGL_DEBUG, "MSC TX %s\n", hexdump(msg->data, msg->len));
+
+	ret = write(fd->fd, msg->data, msg->len);
+	if (ret < msg->len)
+		perror("MSC: Failed to send SCCP");
+
+	return ret;
+}
+
+static int ipaccess_a_fd_cb(struct bsc_fd *bfd)
+{
+	int error;
+	struct msgb *msg = ipaccess_read_msg(bfd, &error);
+	struct ipaccess_head *hh;
+	struct osmo_msc_data *data = (struct osmo_msc_data *) bfd->data;
+
+	if (!msg) {
+		if (error == 0) {
+			LOGP(DMSC, LOGL_ERROR, "The connection to the MSC was lost.\n");
+			bsc_msc_lost(data->msc_con);
+			return -1;
+		}
+
+		LOGP(DMSC, LOGL_ERROR, "Failed to parse ip access message: %d\n", error);
+		return -1;
+	}
+
+	LOGP(DMSC, LOGL_DEBUG, "From MSC: %s proto: %d\n", hexdump(msg->data, msg->len), msg->l2h[0]);
+
+	/* handle base message handling */
+	hh = (struct ipaccess_head *) msg->data;
+	ipaccess_rcvmsg_base(msg, bfd);
+
+	/* initialize the networking. This includes sending a GSM08.08 message */
+	if (hh->proto == IPAC_PROTO_IPACCESS) {
+		if (msg->l2h[0] == IPAC_MSGT_ID_ACK)
+			initialize_if_needed(data->msc_con);
+		else if (msg->l2h[0] == IPAC_MSGT_ID_GET) {
+			send_id_get_response(data, bfd->fd);
+		} else if (msg->l2h[0] == IPAC_MSGT_PONG) {
+			bsc_del_timer(&data->pong_timer);
+		}
+	} else if (hh->proto == IPAC_PROTO_SCCP) {
+		sccp_system_incoming(msg);
+	} else if (hh->proto == IPAC_PROTO_MGCP_OLD) {
+		mgcp_forward(data, msg);
+	}
+
+	msgb_free(msg);
+	return 0;
+}
+
+static void send_ping(struct osmo_msc_data *data)
+{
+	struct msgb *msg;
+
+	msg = msgb_alloc_headroom(4096, 128, "ping");
+	if (!msg) {
+		LOGP(DMSC, LOGL_ERROR, "Failed to create PING.\n");
+		return;
+	}
+
+	msg->l2h = msgb_put(msg, 1);
+	msg->l2h[0] = IPAC_MSGT_PING;
+
+	msc_queue_write(data->msc_con, msg, IPAC_PROTO_IPACCESS);
+}
+
+static void msc_ping_timeout_cb(void *_data)
+{
+	struct osmo_msc_data *data = (struct osmo_msc_data *) _data;
+	if (data->ping_timeout < 0)
+		return;
+
+	send_ping(data);
+
+	/* send another ping in 20 seconds */
+	bsc_schedule_timer(&data->ping_timer, data->ping_timeout, 0);
+
+	/* also start a pong timer */
+	bsc_schedule_timer(&data->pong_timer, data->pong_timeout, 0);
+}
+
+static void msc_pong_timeout_cb(void *_data)
+{
+	struct osmo_msc_data *data = (struct osmo_msc_data *) _data;
+
+	LOGP(DMSC, LOGL_ERROR, "MSC didn't answer PING. Closing connection.\n");
+	bsc_msc_lost(data->msc_con);
+}
+
+static void msc_connection_connected(struct bsc_msc_connection *con)
+{
+	struct msc_signal_data sig;
+	struct osmo_msc_data *data;
+	int ret, on;
+	on = 1;
+	ret = setsockopt(con->write_queue.bfd.fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
+	if (ret != 0)
+                LOGP(DMSC, LOGL_ERROR, "Failed to set TCP_NODELAY: %s\n", strerror(errno));
+
+	data = (struct osmo_msc_data *) con->write_queue.bfd.data;
+	msc_ping_timeout_cb(data);
+
+	sig.data = data;
+	dispatch_signal(SS_MSC, S_MSC_CONNECTED, &sig);
+}
+
+/*
+ * The connection to the MSC was lost and we will need to free all
+ * resources and then attempt to reconnect.
+ */
+static void msc_connection_was_lost(struct bsc_msc_connection *msc)
+{
+	struct msc_signal_data sig;
+	struct osmo_msc_data *data;
+
+	LOGP(DMSC, LOGL_ERROR, "Lost MSC connection. Freing stuff.\n");
+
+	data = (struct osmo_msc_data *) msc->write_queue.bfd.data;
+	bsc_del_timer(&data->ping_timer);
+	bsc_del_timer(&data->pong_timer);
+
+	sig.data = data;
+	dispatch_signal(SS_MSC, S_MSC_LOST, &sig);
+
+	msc->is_authenticated = 0;
+	bsc_msc_schedule_connect(msc);
+}
+
+static void initialize_if_needed(struct bsc_msc_connection *conn)
+{
+	struct msgb *msg;
+
+	if (!conn->is_authenticated) {
+		/* send a gsm 08.08 reset message from here */
+		msg = gsm0808_create_reset();
+		if (!msg) {
+			LOGP(DMSC, LOGL_ERROR, "Failed to create the reset message.\n");
+			return;
+		}
+
+		sccp_write(msg, &sccp_ssn_bssap, &sccp_ssn_bssap, 0);
+		msgb_free(msg);
+		conn->is_authenticated = 1;
+	}
+}
+
+static void send_id_get_response(struct osmo_msc_data *data, int fd)
+{
+	struct msgb *msg;
+
+	msg = bsc_msc_id_get_resp(data->bsc_token);
+	if (!msg)
+		return;
+	msc_queue_write(data->msc_con, msg, IPAC_PROTO_IPACCESS);
+}
+
+int osmo_bsc_msc_init(struct gsm_network *network)
+{
+	struct osmo_msc_data *data = network->msc_data;
+
+	if (mgcp_create_port(data) != 0)
+		return -1;
+
+	data->msc_con = bsc_msc_create(data->msc_ip,
+				       data->msc_port,
+				       data->msc_ip_dscp);
+	if (!data->msc_con) {
+		LOGP(DMSC, LOGL_ERROR, "Creating the MSC network connection failed.\n");
+		return -1;
+	}
+
+	data->ping_timer.cb = msc_ping_timeout_cb;
+	data->ping_timer.data = data;
+	data->pong_timer.cb = msc_pong_timeout_cb;
+	data->pong_timer.data = data;
+
+	data->msc_con->write_queue.bfd.data = data;
+	data->msc_con->connection_loss = msc_connection_was_lost;
+	data->msc_con->connected = msc_connection_connected;
+	data->msc_con->write_queue.read_cb = ipaccess_a_fd_cb;
+	data->msc_con->write_queue.write_cb = msc_alink_do_write;
+	bsc_msc_connect(data->msc_con);
+
+	return 0;
+}