[mobile] Adding socket application interface code from OpenBSC.

2 files changed, 363 insertions, 0 deletions

diff --git a/src/host/layer23/include/osmocom/bb/mobile/mncc_sock.h b/src/host/layer23/include/osmocom/bb/mobile/mncc_sock.h
new file mode 100644
index 00000000..b38c5bc6
--- /dev/null
+++ b/src/host/layer23/include/osmocom/bb/mobile/mncc_sock.h
@@ -0,0 +1,16 @@
+#ifndef _MNCC_SOCK_H
+#define _MNCC_SOCK_H
+
+struct mncc_sock_state {
+	void *inst;
+	struct osmo_fd listen_bfd;	/* fd for listen socket */
+	struct osmo_fd conn_bfd;		/* fd for connection to lcr */
+	struct llist_head upqueue;
+};
+
+int mncc_sock_from_cc(struct mncc_sock_state *state, struct msgb *msg);
+void mncc_sock_write_pending(struct mncc_sock_state *state);
+struct mncc_sock_state *mncc_sock_init(void *inst, const char *name, void *tall_ctx);
+void mncc_sock_exit(struct mncc_sock_state *state);
+
+#endif /* _MNCC_SOCK_H */
diff --git a/src/host/layer23/src/mobile/mncc_sock.c b/src/host/layer23/src/mobile/mncc_sock.c
new file mode 100644
index 00000000..1e239428
--- /dev/null
+++ b/src/host/layer23/src/mobile/mncc_sock.c
@@ -0,0 +1,347 @@
+/* mncc_sock.c: Tie the MNCC interface to a unix domain socket */
+
+/* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2009,2011 by Andreas Eversberg <andreas@eversberg.eu>
+ * 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 <assert.h>
+#include <stdint.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+
+#include <osmocom/bb/common/logging.h>
+#include <osmocom/bb/mobile/mncc.h>
+#include <osmocom/bb/mobile/mncc_sock.h>
+#include <osmocom/bb/mobile/gsm48_cc.h>
+
+/* input from CC code into mncc_sock */
+int mncc_sock_from_cc(struct mncc_sock_state *state, struct msgb *msg)
+{
+	struct gsm_mncc *mncc_in = (struct gsm_mncc *) msgb_data(msg);
+	int msg_type = mncc_in->msg_type;
+
+	/* Check if we currently have a MNCC handler connected */
+	if (state->conn_bfd.fd < 0) {
+		LOGP(DMNCC, LOGL_ERROR, "mncc_sock receives %s for external CC app "
+			"but socket is gone\n", get_mncc_name(msg_type));
+		if (msg_type != GSM_TCHF_FRAME
+		 && msg_type != GSM_TCHF_FRAME_EFR
+		 && msg_type != MNCC_REL_IND) {
+			/* release the request */
+			struct gsm_mncc mncc_out;
+			memset(&mncc_out, 0, sizeof(mncc_out));
+			mncc_out.callref = mncc_in->callref;
+			mncc_set_cause(&mncc_out, GSM48_CAUSE_LOC_PRN_S_LU,
+					GSM48_CC_CAUSE_TEMP_FAILURE);
+			mncc_tx_to_cc(state->inst, MNCC_REL_REQ, &mncc_out);
+		}
+		/* free the original message */
+		msgb_free(msg);
+		return -1;
+	}
+
+	/* FIXME: check for some maximum queue depth? */
+
+	/* Actually enqueue the message and mark socket write need */
+	msgb_enqueue(&state->upqueue, msg);
+	state->conn_bfd.when |= BSC_FD_WRITE;
+	return 0;
+}
+
+void mncc_sock_write_pending(struct mncc_sock_state *state)
+{
+	state->conn_bfd.when |= BSC_FD_WRITE;
+}
+
+/* FIXME: move this to libosmocore */
+int osmo_unixsock_listen(struct osmo_fd *bfd, int type, const char *path);
+
+static void mncc_sock_close(struct mncc_sock_state *state)
+{
+	struct osmo_fd *bfd = &state->conn_bfd;
+
+	LOGP(DMNCC, LOGL_NOTICE, "MNCC Socket has closed connection\n");
+
+	close(bfd->fd);
+	bfd->fd = -1;
+	osmo_fd_unregister(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 */
+
+	/* release all exisitng calls */
+	mncc_clear_trans(state->inst, GSM48_PDISC_CC);
+
+	/* flush the queue */
+	while (!llist_empty(&state->upqueue)) {
+		struct msgb *msg = msgb_dequeue(&state->upqueue);
+		msgb_free(msg);
+	}
+}
+
+static int mncc_sock_read(struct osmo_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;
+		goto close;
+	}
+
+	rc = mncc_tx_to_cc(state->inst, 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:
+	msgb_free(msg);
+	mncc_sock_close(state);
+	return -1;
+}
+
+static int mncc_sock_write(struct osmo_fd *bfd)
+{
+	struct mncc_sock_state *state = bfd->data;
+	int rc;
+
+	while (!llist_empty(&state->upqueue)) {
+		struct msgb *msg, *msg2;
+		struct gsm_mncc *mncc_prim;
+
+		/* peek at the beginning of the queue */
+		msg = llist_entry(state->upqueue.next, struct msgb, list);
+		mncc_prim = (struct gsm_mncc *)msg->data;
+
+		bfd->when &= ~BSC_FD_WRITE;
+
+		/* bug hunter 8-): maybe someone forgot msgb_put(...) ? */
+		if (!msgb_length(msg)) {
+			LOGP(DMNCC, LOGL_ERROR, "message type (%d) with ZERO "
+				"bytes!\n", mncc_prim->msg_type);
+			goto dontsend;
+		}
+
+		/* 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;
+		}
+
+dontsend:
+		/* _after_ we send it, we can deueue */
+		msg2 = msgb_dequeue(&state->upqueue);
+		assert(msg == msg2);
+		msgb_free(msg);
+	}
+	return 0;
+
+close:
+	mncc_sock_close(state);
+
+	return -1;
+}
+
+static int mncc_sock_cb(struct osmo_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 osmo_fd *bfd, unsigned int flags)
+{
+	struct mncc_sock_state *state = (struct mncc_sock_state *)bfd->data;
+	struct osmo_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) {
+		LOGP(DMNCC, LOGL_ERROR, "Failed to accept a new connection\n");
+		return -1;
+	}
+
+	if (conn_bfd->fd >= 0) {
+		LOGP(DMNCC, LOGL_NOTICE, "MNCC app connects but we already have "
+			"another active connection ?!?\n");
+		/* We already have one MNCC app connected, this is all we support */
+		state->listen_bfd.when &= ~BSC_FD_READ;
+		close(rc);
+		return 0;
+	}
+
+	conn_bfd->fd = rc;
+	conn_bfd->when = BSC_FD_READ;
+	conn_bfd->cb = mncc_sock_cb;
+	conn_bfd->data = state;
+
+	if (osmo_fd_register(conn_bfd) != 0) {
+		LOGP(DMNCC, LOGL_ERROR, "Failed to register new connection fd\n");
+		close(conn_bfd->fd);
+		conn_bfd->fd = -1;
+		return -1;
+	}
+
+	LOGP(DMNCC, LOGL_NOTICE, "MNCC Socket has connection with external "
+		"call control application\n");
+
+	return 0;
+}
+
+
+struct mncc_sock_state *mncc_sock_init(void *inst, const char *name, void *tall_ctx)
+{
+	struct mncc_sock_state *state;
+	struct osmo_fd *bfd;
+	int rc;
+
+	state = talloc_zero(tall_ctx, struct mncc_sock_state);
+	if (!state)
+		return NULL;
+
+	state->inst = inst;
+	INIT_LLIST_HEAD(&state->upqueue);
+	state->conn_bfd.fd = -1;
+
+	bfd = &state->listen_bfd;
+
+	rc = osmo_unixsock_listen(bfd, SOCK_SEQPACKET, name);
+	if (rc < 0) {
+		LOGP(DMNCC, LOGL_ERROR, "Could not create unix socket: %s\n",
+			strerror(errno));
+		talloc_free(state);
+		return NULL;
+	}
+
+	bfd->when = BSC_FD_READ;
+	bfd->cb = mncc_sock_accept;
+	bfd->data = state;
+
+	rc = osmo_fd_register(bfd);
+	if (rc < 0) {
+		LOGP(DMNCC, LOGL_ERROR, "Could not register listen fd: %d\n", rc);
+		close(bfd->fd);
+		talloc_free(state);
+		return NULL;
+	}
+
+	return state;
+}
+
+void mncc_sock_exit(struct mncc_sock_state *state)
+{
+	if (state->conn_bfd.fd > -1)
+		mncc_sock_close(state);
+	osmo_fd_unregister(&state->listen_bfd);
+	close(state->listen_bfd.fd);
+	talloc_free(state);
+}
+
+/* FIXME: move this to libosmocore */
+int osmo_unixsock_listen(struct osmo_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;
+}