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-rw-r--r--openbsc/src/libmgcp/mgcpgw_client.c549
1 files changed, 549 insertions, 0 deletions
diff --git a/openbsc/src/libmgcp/mgcpgw_client.c b/openbsc/src/libmgcp/mgcpgw_client.c
new file mode 100644
index 000000000..9f0c84de2
--- /dev/null
+++ b/openbsc/src/libmgcp/mgcpgw_client.c
@@ -0,0 +1,549 @@
+/* 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/select.h>
+#include <osmocom/core/write_queue.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/logging.h>
+
+#include <openbsc/mgcpgw_client.h>
+#include <openbsc/mgcp.h>
+#include <openbsc/mgcp_internal.h>
+#include <openbsc/debug.h>
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+
+struct mgcpgw_client {
+ struct mgcpgw_client_conf actual;
+ uint32_t remote_addr;
+ struct osmo_wqueue wq;
+ mgcp_trans_id_t next_trans_id;
+ uint16_t next_endpoint;
+ struct llist_head responses_pending;
+};
+
+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,
+ };
+}
+
+unsigned int mgcpgw_client_next_endpoint(struct mgcpgw_client *client)
+{
+ return client->next_endpoint ++;
+}
+
+static void mgcpgw_client_handle_response(struct mgcpgw_client *mgcp,
+ struct mgcp_response_pending *pending,
+ struct mgcp_response *response)
+{
+ if (!pending) {
+ LOGP(DMGCP, LOGL_ERROR,
+ "Cannot handle NULL response\n");
+ return;
+ }
+ if (pending->response_cb)
+ pending->response_cb(response, pending->priv);
+ else
+ LOGP(DMGCP, 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(DMGCP, 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(DMGCP, 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(DMGCP, 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(DMGCP, 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(DMGCP, LOGL_ERROR, "Cannot parse MGCP response\n");
+ return -1;
+ }
+
+ pending = mgcpgw_client_response_pending_get(mgcp, &r);
+ if (!pending) {
+ LOGP(DMGCP, 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(DMGCP, LOGL_ERROR, "Failed to allocate MGCP message.\n");
+ return -1;
+ }
+
+ ret = read(fd->fd, msg->data, 4096 - 128);
+ if (ret <= 0) {
+ LOGP(DMGCP, LOGL_ERROR, "Failed to read: %d/%s\n", errno, strerror(errno));
+ msgb_free(msg);
+ return -1;
+ } else if (ret > 4096 - 128) {
+ LOGP(DMGCP, 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)-1 ? msg->len : sizeof(strbuf)-1;
+ strncpy(strbuf, (const char*)msg->data, l);
+ strbuf[l] = '\0';
+ DEBUGP(DMGCP, "Tx MGCP msg to MGCP GW: '%s'\n", strbuf);
+
+ 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;
+}
+
+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);
+
+ mgcp->next_trans_id = 1;
+ mgcp->next_endpoint = 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;
+
+ 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(DMGCP, 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(DMGCP, 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(DMGCP, 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(DMGCP, 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(DMGCP, 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(DMGCP, LOGL_FATAL, "Failed to register BFD\n");
+ rc = -EIO;
+ goto error_close_fd;
+ }
+ LOGP(DMGCP, 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(DMGCP, 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(DMGCP, 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(DMGCP, LOGL_FATAL, "Could not queue message to MGCP GW\n");
+ msgb_free(msg);
+ goto mgcp_tx_error;
+ } else
+ LOGP(DMGCP, 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(DMGCP, 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(DMGCP, LOGL_ERROR,
+ "Message too large: trans_id=%u len=%d\n",
+ trans_id, len);
+ return NULL;
+ }
+ if (len < 1) {
+ LOGP(DMGCP, 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);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-19 19:59:11 +0000