split off osmo-mgw: remove files, apply build, rename

Add vty and logging previously used from libcommon

Rename libmgcp to libosmo-legacy-mgcp and install.

Use DLMGCP, not DMGCP.

Slim down the public mgcpgw_client API, move all elements not actually used by
current callers to private headers / static c.

Depends: libosmocore I09c587e2d59472cbde852d467d457254746d9e67
Change-Id: I71a0a16ebaaef881c34235849601fc40aa12cfd7
diff --git a/src/libosmo-legacy-mgcp/mgcpgw_client.c b/src/libosmo-legacy-mgcp/mgcpgw_client.c
new file mode 100644
index 0000000..810ba16
--- /dev/null
+++ b/src/libosmo-legacy-mgcp/mgcpgw_client.c
@@ -0,0 +1,622 @@
+/* mgcp_utils - common functions to setup an MGCP connection
+ */
+/* (C) 2016 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ * 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 <osmocom/core/linuxlist.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/write_queue.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/logging.h>
+
+#include <osmocom/legacy_mgcp/mgcpgw_client.h>
+#include <osmocom/legacy_mgcp/mgcp.h>
+#include <osmocom/legacy_mgcp/mgcp_internal.h>
+#include <osmocom/legacy_mgcp/mgcpgw_client_internal.h>
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+
+void mgcpgw_client_conf_init(struct mgcpgw_client_conf *conf)
+{
+	/* NULL and -1 default to MGCPGW_CLIENT_*_DEFAULT values */
+	*conf = (struct mgcpgw_client_conf){
+		.local_addr = NULL,
+		.local_port = -1,
+		.remote_addr = NULL,
+		.remote_port = -1,
+		.first_endpoint = 0,
+		.last_endpoint = 0,
+		.bts_base = 0,
+	};
+}
+
+/* Test if a given endpoint id is currently in use */
+static bool endpoint_in_use(uint16_t id, struct mgcpgw_client *client)
+{
+	struct mgcp_inuse_endpoint *endpoint;
+	llist_for_each_entry(endpoint, &client->inuse_endpoints, entry) {
+		if (endpoint->id == id)
+			return true;
+	}
+
+	return false;
+}
+
+/* Find and seize an unsused endpoint id */
+int mgcpgw_client_next_endpoint(struct mgcpgw_client *client)
+{
+	int i;
+	uint16_t first_endpoint = client->actual.first_endpoint;
+	uint16_t last_endpoint = client->actual.last_endpoint;
+	struct mgcp_inuse_endpoint *endpoint;
+
+	/* Use the maximum permitted range if the VTY
+	 * configuration does not specify a range */
+	if (client->actual.last_endpoint == 0) {
+		first_endpoint = 1;
+		last_endpoint = 65534;
+	}
+
+	/* Test the permitted endpoint range for an endpoint
+	 * number that is not in use. When a suitable endpoint
+	 * number can be found, seize it by adding it to the
+	 * inuse list. */
+	for (i=first_endpoint;i<last_endpoint;i++)
+	{
+		if (endpoint_in_use(i,client) == false) {
+			endpoint = talloc_zero(client, struct mgcp_inuse_endpoint);
+			endpoint->id = i;
+			llist_add_tail(&endpoint->entry, &client->inuse_endpoints);
+			return endpoint->id;
+		}
+	}
+
+	/* All endpoints are busy! */
+	return -EINVAL;
+}
+
+/* Release a seized endpoint id to make it available again for other calls */
+void mgcpgw_client_release_endpoint(uint16_t id, struct mgcpgw_client *client)
+{
+	struct mgcp_inuse_endpoint *endpoint;
+	struct mgcp_inuse_endpoint *endpoint_tmp;
+	llist_for_each_entry_safe(endpoint, endpoint_tmp, &client->inuse_endpoints, entry) {
+		if (endpoint->id == id) {
+			llist_del(&endpoint->entry);
+			talloc_free(endpoint);
+		}
+	}
+}
+
+static void mgcpgw_client_handle_response(struct mgcpgw_client *mgcp,
+					  struct mgcp_response_pending *pending,
+					  struct mgcp_response *response)
+{
+	if (!pending) {
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "Cannot handle NULL response\n");
+		return;
+	}
+	if (pending->response_cb)
+		pending->response_cb(response, pending->priv);
+	else
+		LOGP(DLMGCP, LOGL_INFO, "MGCP response ignored (NULL cb)\n");
+	talloc_free(pending);
+}
+
+static int mgcp_response_parse_head(struct mgcp_response *r, struct msgb *msg)
+{
+	int comment_pos;
+	char *end;
+
+	if (mgcp_msg_terminate_nul(msg))
+		goto response_parse_failure;
+
+	r->body = (char *)msg->data;
+
+        if (sscanf(r->body, "%3d %u %n",
+		   &r->head.response_code, &r->head.trans_id,
+		   &comment_pos) != 2)
+		goto response_parse_failure;
+
+	r->head.comment = r->body + comment_pos;
+	end = strchr(r->head.comment, '\r');
+	if (!end)
+		goto response_parse_failure;
+	/* Mark the end of the comment */
+	*end = '\0';
+	r->body = end + 1;
+	if (r->body[0] == '\n')
+		r->body ++;
+	return 0;
+
+response_parse_failure:
+	LOGP(DLMGCP, LOGL_ERROR,
+	     "Failed to parse MGCP response header\n");
+	return -EINVAL;
+}
+
+/* TODO undup against mgcp_protocol.c:mgcp_check_param() */
+static bool mgcp_line_is_valid(const char *line)
+{
+	const size_t line_len = strlen(line);
+	if (line[0] == '\0')
+		return true;
+
+	if (line_len < 2
+	    || line[1] != '=') {
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "Wrong MGCP option format: '%s'\n",
+		     line);
+		return false;
+	}
+
+	return true;
+}
+
+/* Parse a line like "m=audio 16002 RTP/AVP 98" */
+static int mgcp_parse_audio(struct mgcp_response *r, const char *line)
+{
+        if (sscanf(line, "m=audio %hu",
+		   &r->audio_port) != 1)
+		goto response_parse_failure;
+
+	return 0;
+
+response_parse_failure:
+	LOGP(DLMGCP, LOGL_ERROR,
+	     "Failed to parse MGCP response header\n");
+	return -EINVAL;
+}
+
+int mgcp_response_parse_params(struct mgcp_response *r)
+{
+	char *line;
+	int rc;
+	OSMO_ASSERT(r->body);
+	char *data = strstr(r->body, "\n\n");
+
+	if (!data) {
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "MGCP response: cannot find start of parameters\n");
+		return -EINVAL;
+	}
+
+	/* Advance to after the \n\n, replace the second \n with \0. That's
+	 * where the parameters start. */
+	data ++;
+	*data = '\0';
+	data ++;
+
+	for_each_line(line, data) {
+		if (!mgcp_line_is_valid(line))
+			return -EINVAL;
+
+		switch (line[0]) {
+		case 'm':
+			rc = mgcp_parse_audio(r, line);
+			if (rc)
+				return rc;
+			break;
+		default:
+			/* skip unhandled parameters */
+			break;
+		}
+	}
+	return 0;
+}
+
+static struct mgcp_response_pending *mgcpgw_client_response_pending_get(
+					 struct mgcpgw_client *mgcp,
+					 struct mgcp_response *r)
+{
+	struct mgcp_response_pending *pending;
+	if (!r)
+		return NULL;
+	llist_for_each_entry(pending, &mgcp->responses_pending, entry) {
+		if (pending->trans_id == r->head.trans_id) {
+			llist_del(&pending->entry);
+			return pending;
+		}
+	}
+	return NULL;
+}
+
+/* Feed an MGCP message into the receive processing.
+ * Parse the head and call any callback registered for the transaction id found
+ * in the MGCP message. This is normally called directly from the internal
+ * mgcp_do_read that reads from the socket connected to the MGCP gateway. This
+ * function is published mainly to be able to feed data from the test suite.
+ */
+int mgcpgw_client_rx(struct mgcpgw_client *mgcp, struct msgb *msg)
+{
+	struct mgcp_response r = { 0 };
+	struct mgcp_response_pending *pending;
+	int rc;
+
+	rc = mgcp_response_parse_head(&r, msg);
+	if (rc) {
+		LOGP(DLMGCP, LOGL_ERROR, "Cannot parse MGCP response\n");
+		return -1;
+	}
+
+	pending = mgcpgw_client_response_pending_get(mgcp, &r);
+	if (!pending) {
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "Cannot find matching MGCP transaction for trans_id %d\n",
+		     r.head.trans_id);
+		return -1;
+	}
+
+	mgcpgw_client_handle_response(mgcp, pending, &r);
+	return 0;
+}
+
+static int mgcp_do_read(struct osmo_fd *fd)
+{
+	struct mgcpgw_client *mgcp = fd->data;
+	struct msgb *msg;
+	int ret;
+
+	msg = msgb_alloc_headroom(4096, 128, "mgcp_from_gw");
+	if (!msg) {
+		LOGP(DLMGCP, LOGL_ERROR, "Failed to allocate MGCP message.\n");
+		return -1;
+	}
+
+	ret = read(fd->fd, msg->data, 4096 - 128);
+	if (ret <= 0) {
+		LOGP(DLMGCP, LOGL_ERROR, "Failed to read: %d/%s\n", errno, strerror(errno));
+		msgb_free(msg);
+		return -1;
+	} else if (ret > 4096 - 128) {
+		LOGP(DLMGCP, LOGL_ERROR, "Too much data: %d\n", ret);
+		msgb_free(msg);
+		return -1;
+        }
+
+	msg->l2h = msgb_put(msg, ret);
+	ret = mgcpgw_client_rx(mgcp, msg);
+	talloc_free(msg);
+	return ret;
+}
+
+static int mgcp_do_write(struct osmo_fd *fd, struct msgb *msg)
+{
+	int ret;
+	static char strbuf[4096];
+	unsigned int l = msg->len < sizeof(strbuf) ? msg->len : sizeof(strbuf);
+	unsigned int i;
+
+	strncpy(strbuf, (const char*)msg->data, l);
+	for (i = 0; i < sizeof(strbuf); i++) {
+		if (strbuf[i] == '\n' || strbuf[i] == '\r') {
+			strbuf[i] = '\0';
+			break;
+		}
+	}
+	DEBUGP(DLMGCP, "Tx MGCP msg to MGCP GW: '%s'\n", strbuf);
+
+	LOGP(DLMGCP, 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(DLMGCP, LOGL_ERROR, "Failed to forward message to MGCP"
+		     " GW: %s\n", strerror(errno));
+
+	return ret;
+}
+
+struct mgcpgw_client *mgcpgw_client_init(void *ctx,
+					 struct mgcpgw_client_conf *conf)
+{
+	struct mgcpgw_client *mgcp;
+
+	mgcp = talloc_zero(ctx, struct mgcpgw_client);
+
+	INIT_LLIST_HEAD(&mgcp->responses_pending);
+	INIT_LLIST_HEAD(&mgcp->inuse_endpoints);
+
+	mgcp->next_trans_id = 1;
+
+	mgcp->actual.local_addr = conf->local_addr ? conf->local_addr :
+		MGCPGW_CLIENT_LOCAL_ADDR_DEFAULT;
+	mgcp->actual.local_port = conf->local_port >= 0 ? (uint16_t)conf->local_port :
+		MGCPGW_CLIENT_LOCAL_PORT_DEFAULT;
+
+	mgcp->actual.remote_addr = conf->remote_addr ? conf->remote_addr :
+		MGCPGW_CLIENT_REMOTE_ADDR_DEFAULT;
+	mgcp->actual.remote_port = conf->remote_port >= 0 ? (uint16_t)conf->remote_port :
+		MGCPGW_CLIENT_REMOTE_PORT_DEFAULT;
+
+	mgcp->actual.first_endpoint = conf->first_endpoint > 0 ? (uint16_t)conf->first_endpoint : 0;
+	mgcp->actual.last_endpoint = conf->last_endpoint > 0 ? (uint16_t)conf->last_endpoint : 0;
+	mgcp->actual.bts_base = conf->bts_base > 0 ? (uint16_t)conf->bts_base : 4000;
+
+	return mgcp;
+}
+
+int mgcpgw_client_connect(struct mgcpgw_client *mgcp)
+{
+	int on;
+	struct sockaddr_in addr;
+	struct osmo_wqueue *wq;
+	int rc;
+
+	if (!mgcp) {
+		LOGP(DLMGCP, LOGL_FATAL, "MGCPGW client not initialized properly\n");
+		return -EINVAL;
+	}
+
+	wq = &mgcp->wq;
+
+	wq->bfd.fd = socket(AF_INET, SOCK_DGRAM, 0);
+	if (wq->bfd.fd < 0) {
+		LOGP(DLMGCP, LOGL_FATAL, "Failed to create UDP socket errno: %d\n", errno);
+		return -errno;
+	}
+
+	on = 1;
+	if (setsockopt(wq->bfd.fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) {
+		LOGP(DLMGCP, LOGL_FATAL,
+		     "Failed to initialize socket for MGCP GW: %s\n",
+		     strerror(errno));
+		rc = -errno;
+		goto error_close_fd;
+	}
+
+	/* bind socket */
+	memset(&addr, 0, sizeof(addr));
+	addr.sin_family = AF_INET;
+	inet_aton(mgcp->actual.local_addr, &addr.sin_addr);
+	addr.sin_port = htons(mgcp->actual.local_port);
+	if (bind(wq->bfd.fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		LOGP(DLMGCP, LOGL_FATAL,
+		     "Failed to bind for MGCP GW to %s %u\n",
+		     mgcp->actual.local_addr, mgcp->actual.local_port);
+		rc = -errno;
+		goto error_close_fd;
+	}
+
+	/* connect to the remote */
+	inet_aton(mgcp->actual.remote_addr, &addr.sin_addr);
+	addr.sin_port = htons(mgcp->actual.remote_port);
+	if (connect(wq->bfd.fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+		LOGP(DLMGCP, LOGL_FATAL,
+		     "Failed to connect to MGCP GW at %s %u: %s\n",
+		     mgcp->actual.remote_addr, mgcp->actual.remote_port,
+		     strerror(errno));
+		rc = -errno;
+		goto error_close_fd;
+	}
+
+	mgcp->remote_addr = htonl(addr.sin_addr.s_addr);
+
+	osmo_wqueue_init(wq, 10);
+	wq->bfd.when = BSC_FD_READ;
+	wq->bfd.data = mgcp;
+	wq->read_cb = mgcp_do_read;
+	wq->write_cb = mgcp_do_write;
+
+	if (osmo_fd_register(&wq->bfd) != 0) {
+		LOGP(DLMGCP, LOGL_FATAL, "Failed to register BFD\n");
+		rc = -EIO;
+		goto error_close_fd;
+	}
+	LOGP(DLMGCP, LOGL_INFO, "MGCP GW connection: %s:%u -> %s:%u\n",
+	     mgcp->actual.local_addr, mgcp->actual.local_port,
+	     mgcp->actual.remote_addr, mgcp->actual.remote_port);
+
+	return 0;
+error_close_fd:
+	close(wq->bfd.fd);
+	wq->bfd.fd = -1;
+	return rc;
+}
+
+const char *mgcpgw_client_remote_addr_str(struct mgcpgw_client *mgcp)
+{
+	return mgcp->actual.remote_addr;
+}
+
+uint16_t mgcpgw_client_remote_port(struct mgcpgw_client *mgcp)
+{
+	return mgcp->actual.remote_port;
+}
+
+/* Return the MGCP GW binary IPv4 address in network byte order. */
+uint32_t mgcpgw_client_remote_addr_n(struct mgcpgw_client *mgcp)
+{
+	return mgcp->remote_addr;
+}
+
+struct mgcp_response_pending * mgcpgw_client_pending_add(
+					struct mgcpgw_client *mgcp,
+					mgcp_trans_id_t trans_id,
+					mgcp_response_cb_t response_cb,
+					void *priv)
+{
+	struct mgcp_response_pending *pending;
+
+	pending = talloc_zero(mgcp, struct mgcp_response_pending);
+	pending->trans_id = trans_id;
+	pending->response_cb = response_cb;
+	pending->priv = priv;
+	llist_add_tail(&pending->entry, &mgcp->responses_pending);
+
+	return pending;
+}
+
+/* Send the MGCP message in msg to the MGCP GW and handle a response with
+ * response_cb. NOTE: the response_cb still needs to call
+ * mgcp_response_parse_params(response) to get the parsed parameters -- to
+ * potentially save some CPU cycles, only the head line has been parsed when
+ * the response_cb is invoked. */
+int mgcpgw_client_tx(struct mgcpgw_client *mgcp, struct msgb *msg,
+		     mgcp_response_cb_t response_cb, void *priv)
+{
+	struct mgcp_response_pending *pending;
+	mgcp_trans_id_t trans_id;
+	int rc;
+
+	trans_id = msg->cb[MSGB_CB_MGCP_TRANS_ID];
+	if (!trans_id) {
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "Unset transaction id in mgcp send request\n");
+		talloc_free(msg);
+		return -EINVAL;
+	}
+
+	pending = mgcpgw_client_pending_add(mgcp, trans_id, response_cb, priv);
+
+	if (msgb_l2len(msg) > 4096) {
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "Cannot send, MGCP message too large: %u\n",
+		     msgb_l2len(msg));
+		msgb_free(msg);
+		rc = -EINVAL;
+		goto mgcp_tx_error;
+	}
+
+	rc = osmo_wqueue_enqueue(&mgcp->wq, msg);
+	if (rc) {
+		LOGP(DLMGCP, LOGL_FATAL, "Could not queue message to MGCP GW\n");
+		msgb_free(msg);
+		goto mgcp_tx_error;
+	} else
+		LOGP(DLMGCP, LOGL_INFO, "Queued %u bytes for MGCP GW\n",
+		     msgb_l2len(msg));
+	return 0;
+
+mgcp_tx_error:
+	/* Pass NULL to response cb to indicate an error */
+	mgcpgw_client_handle_response(mgcp, pending, NULL);
+	return -1;
+}
+
+static struct msgb *mgcp_msg_from_buf(mgcp_trans_id_t trans_id,
+				      const char *buf, int len)
+{
+	struct msgb *msg;
+
+	if (len > (4096 - 128)) {
+		LOGP(DLMGCP, LOGL_ERROR, "Cannot send to MGCP GW:"
+		     " message too large: %d\n", len);
+		return NULL;
+	}
+
+	msg = msgb_alloc_headroom(4096, 128, "MGCP tx");
+	OSMO_ASSERT(msg);
+
+	char *dst = (char*)msgb_put(msg, len);
+	memcpy(dst, buf, len);
+	msg->l2h = msg->data;
+	msg->cb[MSGB_CB_MGCP_TRANS_ID] = trans_id;
+
+	return msg;
+}
+
+static struct msgb *mgcp_msg_from_str(mgcp_trans_id_t trans_id,
+				      const char *fmt, ...)
+{
+	static char compose[4096 - 128];
+	va_list ap;
+	int len;
+	OSMO_ASSERT(fmt);
+
+	va_start(ap, fmt);
+	len = vsnprintf(compose, sizeof(compose), fmt, ap);
+	va_end(ap);
+	if (len >= sizeof(compose)) {
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "Message too large: trans_id=%u len=%d\n",
+		     trans_id, len);
+		return NULL;
+	}
+	if (len < 1) {
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "Failed to compose message: trans_id=%u len=%d\n",
+		     trans_id, len);
+		return NULL;
+	}
+	return mgcp_msg_from_buf(trans_id, compose, len);
+}
+
+static mgcp_trans_id_t mgcpgw_client_next_trans_id(struct mgcpgw_client *mgcp)
+{
+	/* avoid zero trans_id to distinguish from unset trans_id */
+	if (!mgcp->next_trans_id)
+		mgcp->next_trans_id ++;
+	return mgcp->next_trans_id ++;
+}
+
+struct msgb *mgcp_msg_crcx(struct mgcpgw_client *mgcp,
+			   uint16_t rtp_endpoint, unsigned int call_id,
+			   enum mgcp_connection_mode mode)
+{
+	mgcp_trans_id_t trans_id = mgcpgw_client_next_trans_id(mgcp);
+	return mgcp_msg_from_str(trans_id,
+		 "CRCX %u %x@mgw MGCP 1.0\r\n"
+		 "C: %x\r\n"
+		 "L: p:20, a:AMR, nt:IN\r\n"
+		 "M: %s\r\n"
+		 ,
+		 trans_id,
+		 rtp_endpoint,
+		 call_id,
+		 mgcp_cmode_name(mode));
+}
+
+struct msgb *mgcp_msg_mdcx(struct mgcpgw_client *mgcp,
+			   uint16_t rtp_endpoint, const char *rtp_conn_addr,
+			   uint16_t rtp_port, enum mgcp_connection_mode mode)
+
+{
+	mgcp_trans_id_t trans_id = mgcpgw_client_next_trans_id(mgcp);
+	return mgcp_msg_from_str(trans_id,
+		 "MDCX %u %x@mgw MGCP 1.0\r\n"
+		 "M: %s\r\n"
+		 "\r\n"
+		 "c=IN IP4 %s\r\n"
+		 "m=audio %u RTP/AVP 255\r\n"
+		 ,
+		 trans_id,
+		 rtp_endpoint,
+		 mgcp_cmode_name(mode),
+		 rtp_conn_addr,
+		 rtp_port);
+}
+
+struct msgb *mgcp_msg_dlcx(struct mgcpgw_client *mgcp, uint16_t rtp_endpoint,
+			   unsigned int call_id)
+{
+	mgcp_trans_id_t trans_id = mgcpgw_client_next_trans_id(mgcp);
+	return mgcp_msg_from_str(trans_id,
+				 "DLCX %u %x@mgw MGCP 1.0\r\n"
+				 "C: %x\r\n", trans_id, rtp_endpoint, call_id);
+}
+
+struct mgcpgw_client_conf *mgcpgw_client_conf_actual(struct mgcpgw_client *mgcp)
+{
+	return &mgcp->actual;
+}