MNCC socket: Export MNCC interface via unix domain socket

Using this code we will soon be able to use LCR or other MNCC
applications via a unix domain socket.

The code is not actually used yet after this patch.

2 files changed, 290 insertions, 1 deletions

diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index 029f33838..cc69a729d 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -26,7 +26,8 @@ libbsc_a_SOURCES = abis_rsl.c abis_nm.c gsm_data.c gsm_04_08_utils.c \
 		bts_unknown.c bsc_version.c bsc_api.c bsc_vty.c meas_rep.c gsm_04_80.c
 
 libmsc_a_SOURCES = gsm_subscriber.c db.c \
-		mncc.c mncc_builtin.c gsm_04_08.c gsm_04_11.c transaction.c \
+		mncc.c mncc_builtin.c mncc_sock.c \
+		gsm_04_08.c gsm_04_11.c transaction.c \
 		token_auth.c rrlp.c ussd.c silent_call.c \
 		handover_decision.c auth.c \
 		osmo_msc.c
diff --git a/openbsc/src/mncc_sock.c b/openbsc/src/mncc_sock.c
new file mode 100644
index 000000000..9e728bc14
--- /dev/null
+++ b/openbsc/src/mncc_sock.c
@@ -0,0 +1,288 @@
+/* mncc_sock.c: Tie the MNCC interface to a unix domain socket */
+
+/* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2009 by Andreas Eversberg <Andreas.Eversberg@versatel.de>
+ * 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 <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <osmocore/talloc.h>
+#include <osmocore/select.h>
+
+#include <openbsc/debug.h>
+#include <openbsc/mncc.h>
+#include <openbsc/gsm_data.h>
+
+struct mncc_sock_state {
+	struct gsm_network *net;
+	struct bsc_fd listen_bfd;	/* fd for listen socket */
+	struct bsc_fd conn_bfd;		/* fd for connection to lcr */
+};
+
+/* FIXME: avoid this */
+static struct mncc_sock_state *g_state;
+
+void mncc_sock_write_pending(void)
+{
+	g_state->conn_bfd.when |= BSC_FD_WRITE;
+}
+
+/* FIXME: move this to libosmocore */
+int osmo_unixsock_listen(struct bsc_fd *bfd, int type, const char *path);
+
+static void mncc_sock_close(struct mncc_sock_state *state)
+{
+	struct bsc_fd *bfd = &state->conn_bfd;
+
+	close(bfd->fd);
+	bfd->fd = -1;
+	bsc_unregister_fd(bfd);
+
+	/* re-enable the generation of ACCEPT for new connections */
+	state->listen_bfd.when |= BSC_FD_READ;
+
+	/* FIXME: make sure we don't enqueue anymore */
+	/* FIXME: release all exisitng calls */
+
+	/* flush the queue */
+	while (!llist_empty(&state->net->upqueue)) {
+		struct msgb *msg = msgb_dequeue(&state->net->upqueue);
+		msgb_free(msg);
+	}
+}
+
+static int mncc_sock_read(struct bsc_fd *bfd)
+{
+	struct mncc_sock_state *state = (struct mncc_sock_state *)bfd->data;
+	struct gsm_mncc *mncc_prim;
+	struct msgb *msg;
+	int rc;
+
+	msg = msgb_alloc(sizeof(*mncc_prim)+256, "mncc_sock_rx");
+	if (!msg)
+		return -ENOMEM;
+
+	mncc_prim = (struct gsm_mncc *) msg->tail;
+
+	rc = recv(bfd->fd, msg->tail, msgb_tailroom(msg), 0);
+	if (rc == 0)
+		goto close;
+
+	if (rc < 0) {
+		if (errno == EAGAIN)
+			return 0;
+		fprintf(stderr, "Err from socket: %s\n", strerror(errno));
+		goto close;
+	}
+
+	rc = mncc_tx_to_cc(state->net, mncc_prim->msg_type, mncc_prim);
+
+	/* as we always synchronously process the message in mncc_send() and
+	 * its callbacks, we can free the message here. */
+	msgb_free(msg);
+
+	return rc;
+
+close:
+	mncc_sock_close(state);
+	return -1;
+}
+
+static int mncc_sock_write(struct bsc_fd *bfd)
+{
+	struct mncc_sock_state *state = bfd->data;
+	struct gsm_network *net = state->net;
+	int rc;
+
+	while (!llist_empty(&net->upqueue)) {
+		struct msgb *msg;
+		struct gsm_mncc *mncc_prim;
+
+		/* peek at the beginning of the queue */
+		msg = llist_entry(net->upqueue.next, struct msgb, list);
+		mncc_prim = (struct gsm_mncc *)msg->data;
+
+		bfd->when &= ~BSC_FD_WRITE;
+
+		/* try to send it over the socket */
+		rc = write(bfd->fd, msgb_data(msg), msgb_length(msg));
+		if (rc == 0)
+			goto close;
+		if (rc < 0) {
+			if (errno == EAGAIN) {
+				bfd->when |= BSC_FD_WRITE;
+				break;
+			}
+			goto close;
+		}
+		/* _after_ we send it, we can deueue */
+		msgb_dequeue(&net->upqueue);
+	}
+	return 0;
+
+close:
+	mncc_sock_close(state);
+
+	return -1;
+}
+
+static int mncc_sock_cb(struct bsc_fd *bfd, unsigned int flags)
+{
+	int rc = 0;
+
+	if (flags & BSC_FD_READ)
+		rc = mncc_sock_read(bfd);
+	if (rc < 0)
+		return rc;
+
+	if (flags & BSC_FD_WRITE)
+		rc = mncc_sock_write(bfd);
+
+	return rc;
+}
+
+/* accept a new connection */
+static int mncc_sock_accept(struct bsc_fd *bfd, unsigned int flags)
+{
+	struct mncc_sock_state *state = (struct mncc_sock_state *)bfd->data;
+	struct bsc_fd *conn_bfd = &state->conn_bfd;
+	struct sockaddr_un un_addr;
+	socklen_t len;
+	int rc;
+
+	len = sizeof(un_addr);
+	rc = accept(bfd->fd, (struct sockaddr *) &un_addr, &len);
+	if (rc < 0) {
+		fprintf(stderr, "Failed to accept a new connection.\n");
+		return -1;
+	}
+
+	if (conn_bfd->fd > 0) {
+		/* We already have one MNCC app connected, this is all we support */
+		state->listen_bfd.when &= ~BSC_FD_READ;
+		close(rc);
+	}
+
+	conn_bfd->fd = rc;
+	conn_bfd->when = BSC_FD_READ;
+	conn_bfd->cb = mncc_sock_cb;
+	conn_bfd->data = state;
+
+	if (bsc_register_fd(conn_bfd) != 0) {
+		fprintf(stderr, "Failed to register the fd.\n");
+		close(conn_bfd->fd);
+		conn_bfd->fd = -1;
+		state->listen_bfd.when |= ~BSC_FD_READ;
+		return -1;
+	}
+
+	return 0;
+}
+
+
+int mncc_sock_init(struct gsm_network *net)
+{
+	struct mncc_sock_state *state;
+	struct bsc_fd *bfd;
+	int rc;
+
+	state = talloc_zero(tall_bsc_ctx, struct mncc_sock_state);
+	if (!state)
+		return -ENOMEM;
+
+	state->net = net;
+	state->conn_bfd.fd = -1;
+
+	bfd = &state->listen_bfd;
+
+	rc = osmo_unixsock_listen(bfd, SOCK_SEQPACKET, "/tmp/bsc_mncc");
+	if (rc < 0) {
+		talloc_free(state);
+		return rc;
+	}
+
+	bfd->when = BSC_FD_READ;
+	bfd->cb = mncc_sock_accept;
+	bfd->data = state;
+
+	rc = bsc_register_fd(bfd);
+	if (rc < 0) {
+		fprintf(stderr, "Failed to register the bfd.\n");
+		close(bfd->fd);
+		talloc_free(state);
+		return rc;
+	}
+
+	g_state = state;
+
+	return 0;
+}
+
+/* FIXME: move this to libosmocore */
+int osmo_unixsock_listen(struct bsc_fd *bfd, int type, const char *path)
+{
+	struct sockaddr_un local;
+	unsigned int namelen;
+	int rc;
+
+	bfd->fd = socket(AF_UNIX, type, 0);
+
+	if (bfd->fd < 0) {
+		fprintf(stderr, "Failed to create Unix Domain Socket.\n");
+		return -1;
+	}
+
+	local.sun_family = AF_UNIX;
+	strncpy(local.sun_path, path, sizeof(local.sun_path));
+	local.sun_path[sizeof(local.sun_path) - 1] = '\0';
+	unlink(local.sun_path);
+
+	/* we use the same magic that X11 uses in Xtranssock.c for
+	 * calculating the proper length of the sockaddr */
+#if defined(BSD44SOCKETS) || defined(__UNIXWARE__)
+	local.sun_len = strlen(local.sun_path);
+#endif
+#if defined(BSD44SOCKETS) || defined(SUN_LEN)
+	namelen = SUN_LEN(&local);
+#else
+	namelen = strlen(local.sun_path) +
+		  offsetof(struct sockaddr_un, sun_path);
+#endif
+
+	rc = bind(bfd->fd, (struct sockaddr *) &local, namelen);
+	if (rc != 0) {
+		fprintf(stderr, "Failed to bind the unix domain socket. '%s'\n",
+			local.sun_path);
+		return -1;
+	}
+
+	if (listen(bfd->fd, 0) != 0) {
+		fprintf(stderr, "Failed to listen.\n");
+		return -1;
+	}
+
+	return 0;
+}