bsc: Add code responsible for connecting, reconnecting to the MSC
Add the code that is forwarding data, from and to the MSC, also
handling ping/pong timers and authentication. Hook it into the
osmo_bsc. The code is only compile tested and ported from the
on-waves/bsc-master branch.
diff --git a/openbsc/src/bsc/osmo_bsc_msc.c b/openbsc/src/bsc/osmo_bsc_msc.c
new file mode 100644
index 0000000..4b70353
--- /dev/null
+++ b/openbsc/src/bsc/osmo_bsc_msc.c
@@ -0,0 +1,371 @@
+/*
+ * 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 General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <openbsc/bsc_nat.h>
+#include <openbsc/ipaccess.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/osmo_msc_data.h>
+#include <openbsc/debug.h>
+
+#include <osmocore/gsm0808.h>
+
+#include <osmocom/sccp/sccp.h>
+
+#include <sys/socket.h>
+#include <netinet/tcp.h>
+#include <unistd.h>
+
+
+static int msc_queue_write(struct bsc_msc_connection *conn, struct msgb *msg, int proto);
+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, NAT_IPAC_PROTO_MGCP);
+ 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
+ */
+static 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_sccp_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->l2h, msgb_l2len(msg)));
+
+ 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 gsm_network *net = (struct gsm_network *) bfd->data;
+ struct osmo_msc_data *data = net->msc_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 == NAT_IPAC_PROTO_MGCP) {
+ 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 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(con);
+}
+
+/*
+ * 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 osmo_msc_data *data;
+
+ LOGP(DMSC, LOGL_ERROR, "Lost MSC connection. Freing stuff.\n");
+
+#if 0
+ struct bss_sccp_connection_data *bss, *tmp;
+ llist_for_each_entry_safe(bss, tmp, &active_connections, active_connections) {
+ bss_force_close(bss);
+ }
+#else
+#warning "This needs to be ported..."
+#endif
+
+ data = (struct osmo_msc_data *) msc->write_queue.bfd.data;
+ bsc_del_timer(&data->ping_timer);
+ bsc_del_timer(&data->pong_timer);
+
+ 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_sccp_do_write;
+ bsc_msc_connect(data->msc_con);
+
+ return 0;
+}