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osmo-mgw/src/libosmo-mgcp-client/mgcp_client.c

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/* 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 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, 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/core/byteswap.h>
#include <osmocom/core/socket.h>
#include <osmocom/mgcp_client/mgcp_client.h>
#include <osmocom/mgcp_client/mgcp_client_internal.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
/*! Initalize MGCP client configuration struct with default values.
* \param[out] conf Client configuration.*/
void mgcp_client_conf_init(struct mgcp_client_conf *conf)
{
/* NULL and -1 default to MGCP_CLIENT_*_DEFAULT values */
*conf = (struct mgcp_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 mgcp_client *client)
{
struct mgcp_inuse_endpoint *endpoint;
llist_for_each_entry(endpoint, &client->inuse_endpoints, entry) {
if (endpoint->id == id)
return true;
}
return false;
}
/*! Pick next free endpoint ID.
* \param[in,out] client MGCP client descriptor.
* \returns 0 on success, -EINVAL on error. */
int mgcp_client_next_endpoint(struct mgcp_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.
* \param[in] id Endpoint ID
* \param[in,out] client MGCP client descriptor. */
/* Release a seized endpoint id to make it available again for other calls */
void mgcp_client_release_endpoint(uint16_t id, struct mgcp_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 mgcp_client_handle_response(struct mgcp_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;
osmo_strlcpy(r->head.comment, r->body + comment_pos, sizeof(r->head.comment));
end = strchr(r->head.comment, '\r');
if (!end)
goto response_parse_failure;
/* Mark the end of the comment */
*end = '\0';
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_port(struct mgcp_response *r, const char *line)
{
if (sscanf(line, "m=audio %hu",
&r->audio_port) != 1)
goto response_parse_failure;
if (r->audio_port == 0)
goto response_parse_failure;
return 0;
response_parse_failure:
LOGP(DLMGCP, LOGL_ERROR,
"Failed to parse MGCP response header (audio port)\n");
return -EINVAL;
}
/* Parse a line like "c=IN IP4 10.11.12.13" */
static int mgcp_parse_audio_ip(struct mgcp_response *r, const char *line)
{
struct in_addr ip_test;
if (strlen(line) < 16)
goto response_parse_failure;
/* The current implementation strictly supports IPV4 only ! */
if (memcmp("c=IN IP4 ", line, 9) != 0)
goto response_parse_failure;
/* Extract IP-Address */
osmo_strlcpy(r->audio_ip, line + 9, sizeof(r->audio_ip));
/* Check IP-Address */
if (inet_aton(r->audio_ip, &ip_test) == 0)
goto response_parse_failure;
return 0;
response_parse_failure:
LOGP(DLMGCP, LOGL_ERROR,
"Failed to parse MGCP response header (audio ip)\n");
return -EINVAL;
}
/* A new section is marked by a double line break, check a few more
* patterns as there may be variants */
static char *mgcp_find_section_end(char *string)
{
char *rc;
rc = strstr(string, "\n\n");
if (rc)
return rc;
rc = strstr(string, "\n\r\n\r");
if (rc)
return rc;
rc = strstr(string, "\r\n\r\n");
if (rc)
return rc;
return NULL;
}
/*! Parse body (SDP) parameters of the MGCP response
* \param[in,out] r Response data
* \returns 0 on success, -EINVAL on error. */
int mgcp_response_parse_params(struct mgcp_response *r)
{
char *line;
int rc;
char *data;
char *data_ptr;
/* Since this functions performs a destructive parsing, we create a
* local copy of the body data */
OSMO_ASSERT(r->body);
data = talloc_strdup(r, r->body);
OSMO_ASSERT(data);
/* Find beginning of the parameter (SDP) section */
data_ptr = mgcp_find_section_end(data);
if (!data) {
LOGP(DLMGCP, LOGL_ERROR,
"MGCP response: cannot find start of SDP parameters\n");
rc = -EINVAL;
goto exit;
}
/* data_ptr now points to the beginning of the section-end-marker; for_each_non_empty_line()
* skips any \r and \n characters for free, so we don't need to skip the marker. */
for_each_non_empty_line(line, data_ptr) {
if (!mgcp_line_is_valid(line))
return -EINVAL;
switch (line[0]) {
case 'm':
rc = mgcp_parse_audio_port(r, line);
if (rc)
goto exit;
break;
case 'c':
rc = mgcp_parse_audio_ip(r, line);
if (rc)
goto exit;
break;
default:
/* skip unhandled parameters */
break;
}
}
rc = 0;
exit:
talloc_free(data);
return rc;
}
/* Parse a line like "X: something" */
static int mgcp_parse_head_param(char *result, unsigned int result_len,
char label, const char *line)
{
char label_string[4];
/* Detect empty parameters */
if (strlen(line) < 4)
goto response_parse_failure;
/* Check if the label matches */
snprintf(label_string, sizeof(label_string), "%c: ", label);
if (memcmp(label_string, line, 3) != 0)
goto response_parse_failure;
/* Copy payload part of the string to destinations (the label string
* is always 3 chars long) */
osmo_strlcpy(result, line + 3, result_len);
return 0;
response_parse_failure:
LOGP(DLMGCP, LOGL_ERROR,
"Failed to parse MGCP response (parameter label: %c)\n", label);
return -EINVAL;
}
/* Parse MGCP parameters of the response */
static int parse_head_params(struct mgcp_response *r)
{
char *line;
int rc = 0;
OSMO_ASSERT(r->body);
char *data;
char *data_ptr;
char *data_end;
/* Since this functions performs a destructive parsing, we create a
* local copy of the body data */
data = talloc_zero_size(r, strlen(r->body)+1);
OSMO_ASSERT(data);
data_ptr = data;
osmo_strlcpy(data, r->body, strlen(r->body));
/* If there is an SDP body attached, prevent for_each_non_empty_line()
* into running in there, we are not yet interested in the parameters
* stored there. */
data_end = mgcp_find_section_end(data);
if (data_end)
*data_end = '\0';
for_each_non_empty_line(line, data_ptr) {
switch (line[0]) {
case 'Z':
rc = mgcp_parse_head_param(r->head.endpoint,
sizeof(r->head.endpoint),
'Z', line);
if (rc)
goto exit;
/* A specific endpoint identifier returned by the MGW
* must not contain any wildcard characters */
if (strstr(r->head.endpoint, "*") != NULL) {
rc = -EINVAL;
goto exit;
}
/* A specific endpoint identifier returned by the MGW
* must contain an @ character */
if (strstr(r->head.endpoint, "@") == NULL) {
rc = -EINVAL;
goto exit;
}
break;
case 'I':
rc = mgcp_parse_head_param(r->head.conn_id,
sizeof(r->head.conn_id),
'I', line);
if (rc)
goto exit;
break;
default:
/* skip unhandled parameters */
break;
}
}
exit:
talloc_free(data);
return rc;
}
static struct mgcp_response_pending *mgcp_client_response_pending_get(
struct mgcp_client *mgcp,
mgcp_trans_id_t trans_id)
{
struct mgcp_response_pending *pending;
llist_for_each_entry(pending, &mgcp->responses_pending, entry) {
if (pending->trans_id == 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 mgcp_client_rx(struct mgcp_client *mgcp, struct msgb *msg)
{
struct mgcp_response *r;
struct mgcp_response_pending *pending;
int rc;
r = talloc_zero(mgcp, struct mgcp_response);
OSMO_ASSERT(r);
rc = mgcp_response_parse_head(r, msg);
if (rc) {
LOGP(DLMGCP, LOGL_ERROR, "Cannot parse MGCP response (head)\n");
rc = 1;
goto error;
}
rc = parse_head_params(r);
if (rc) {
LOGP(DLMGCP, LOGL_ERROR, "Cannot parse MGCP response (head parameters)\n");
rc = 1;
goto error;
}
pending = mgcp_client_response_pending_get(mgcp, r->head.trans_id);
if (!pending) {
LOGP(DLMGCP, LOGL_ERROR,
"Cannot find matching MGCP transaction for trans_id %d\n",
r->head.trans_id);
rc = -ENOENT;
goto error;
}
mgcp_client_handle_response(mgcp, pending, r);
rc = 0;
error:
talloc_free(r);
return rc;
}
static int mgcp_do_read(struct osmo_fd *fd)
{
struct mgcp_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 = mgcp_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;
osmo_strlcpy(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 mgcp_client *mgcp_client_init(void *ctx,
struct mgcp_client_conf *conf)
{
struct mgcp_client *mgcp;
mgcp = talloc_zero(ctx, struct mgcp_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 :
MGCP_CLIENT_LOCAL_ADDR_DEFAULT;
mgcp->actual.local_port = conf->local_port >= 0 ? (uint16_t)conf->local_port :
MGCP_CLIENT_LOCAL_PORT_DEFAULT;
mgcp->actual.remote_addr = conf->remote_addr ? conf->remote_addr :
MGCP_CLIENT_REMOTE_ADDR_DEFAULT;
mgcp->actual.remote_port = conf->remote_port >= 0 ? (uint16_t)conf->remote_port :
MGCP_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;
}
/*! Initalize client connection (opens socket only, no request is sent yet)
* \param[in,out] mgcp MGCP client descriptor.
* \returns 0 on success, -EINVAL on error. */
int mgcp_client_connect(struct mgcp_client *mgcp)
{
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;
rc = osmo_sock_init2_ofd(&wq->bfd, AF_INET, SOCK_DGRAM, IPPROTO_UDP,
mgcp->actual.local_addr, mgcp->actual.local_port,
mgcp->actual.remote_addr, mgcp->actual.remote_port,
OSMO_SOCK_F_BIND | OSMO_SOCK_F_CONNECT);
if (rc < 0) {
LOGP(DLMGCP, LOGL_FATAL,
"Failed to initialize socket %s:%u -> %s:%u for MGCP GW: %s\n",
mgcp->actual.local_addr, mgcp->actual.local_port,
mgcp->actual.remote_addr, mgcp->actual.remote_port, strerror(errno));
goto error_close_fd;
}
inet_aton(mgcp->actual.remote_addr, &addr.sin_addr);
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;
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;
}
/*! Get the IP-Aaddress of the associated MGW as string.
* \param[in] mgcp MGCP client descriptor.
* \returns a pointer to the address string. */
const char *mgcp_client_remote_addr_str(struct mgcp_client *mgcp)
{
return mgcp->actual.remote_addr;
}
/*! Get the IP-Port of the associated MGW.
* \param[in] mgcp MGCP client descriptor.
* \returns port number. */
uint16_t mgcp_client_remote_port(struct mgcp_client *mgcp)
{
return mgcp->actual.remote_port;
}
/*! Get the IP-Aaddress of the associated MGW as its numeric representation.
* \param[in] mgcp MGCP client descriptor.
* \returns IP-Address as 32 bit integer (network byte order) */
uint32_t mgcp_client_remote_addr_n(struct mgcp_client *mgcp)
{
return mgcp->remote_addr;
}
struct mgcp_response_pending * mgcp_client_pending_add(
struct mgcp_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.
* Before the priv pointer becomes invalid, e.g. due to transaction timeout,
* mgcp_client_cancel() needs to be called for this transaction.
*/
int mgcp_client_tx(struct mgcp_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 = mgcp_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 */
mgcp_client_handle_response(mgcp, pending, NULL);
return -1;
}
/*! Cancel a pending transaction.
* \param[in] mgcp MGCP client descriptor.
* \param[in,out] trans_id Transaction id.
* \returns 0 on success, -ENOENT on error.
*
* Should a priv pointer passed to mgcp_client_tx() become invalid, this function must be called. In
* practical terms, if the caller of mgcp_client_tx() wishes to tear down a transaction without having
* received a response this function must be called. The trans_id can be obtained by calling
* mgcp_msg_trans_id() on the msgb produced by mgcp_msg_gen(). */
int mgcp_client_cancel(struct mgcp_client *mgcp, mgcp_trans_id_t trans_id)
{
struct mgcp_response_pending *pending = mgcp_client_response_pending_get(mgcp, trans_id);
if (!pending) {
/*! Note: it is not harmful to cancel a transaction twice. */
LOGP(DLMGCP, LOGL_INFO, "Cannot cancel, no such transaction: %u\n", trans_id);
return -ENOENT;
}
LOGP(DLMGCP, LOGL_INFO, "Canceled transaction %u\n", trans_id);
talloc_free(pending);
return 0;
/*! We don't really need to clean up the wqueue: In all sane cases, the msgb has already been sent
* out and is no longer in the wqueue. If it still is in the wqueue, then sending MGCP messages
* per se is broken and the program should notice so by a full wqueue. Even if this was called
* before we had a chance to send out the message and it is still going to be sent, we will just
* ignore the reply to it later. Removing a msgb from the wqueue here would just introduce more
* bug surface in terms of failing to update wqueue API's counters or some such.
*/
}
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 mgcp_client_next_trans_id(struct mgcp_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 mgcp_client *mgcp,
uint16_t rtp_endpoint, unsigned int call_id,
enum mgcp_connection_mode mode)
{
mgcp_trans_id_t trans_id = mgcp_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_client_cmode_name(mode));
}
struct msgb *mgcp_msg_mdcx(struct mgcp_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 = mgcp_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_client_cmode_name(mode),
rtp_conn_addr,
rtp_port);
}
struct msgb *mgcp_msg_dlcx(struct mgcp_client *mgcp, uint16_t rtp_endpoint,
unsigned int call_id)
{
mgcp_trans_id_t trans_id = mgcp_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);
}
#define MGCP_CRCX_MANDATORY (MGCP_MSG_PRESENCE_ENDPOINT | \
MGCP_MSG_PRESENCE_CALL_ID | \
MGCP_MSG_PRESENCE_CONN_MODE)
#define MGCP_MDCX_MANDATORY (MGCP_MSG_PRESENCE_ENDPOINT | \
MGCP_MSG_PRESENCE_CALL_ID | \
MGCP_MSG_PRESENCE_CONN_ID)
#define MGCP_DLCX_MANDATORY (MGCP_MSG_PRESENCE_ENDPOINT)
#define MGCP_AUEP_MANDATORY (MGCP_MSG_PRESENCE_ENDPOINT)
#define MGCP_RSIP_MANDATORY 0 /* none */
/*! Generate an MGCP message
* \param[in] mgcp MGCP client descriptor.
* \param[in] mgcp_msg Message description
* \returns message buffer on success, NULL on error. */
struct msgb *mgcp_msg_gen(struct mgcp_client *mgcp, struct mgcp_msg *mgcp_msg)
{
mgcp_trans_id_t trans_id = mgcp_client_next_trans_id(mgcp);
uint32_t mandatory_mask;
struct msgb *msg = msgb_alloc_headroom(4096, 128, "MGCP tx");
int rc = 0;
char local_ip[INET_ADDRSTRLEN];
msg->l2h = msg->data;
msg->cb[MSGB_CB_MGCP_TRANS_ID] = trans_id;
/* Add command verb */
switch (mgcp_msg->verb) {
case MGCP_VERB_CRCX:
mandatory_mask = MGCP_CRCX_MANDATORY;
rc += msgb_printf(msg, "CRCX %u", trans_id);
break;
case MGCP_VERB_MDCX:
mandatory_mask = MGCP_MDCX_MANDATORY;
rc += msgb_printf(msg, "MDCX %u", trans_id);
break;
case MGCP_VERB_DLCX:
mandatory_mask = MGCP_DLCX_MANDATORY;
rc += msgb_printf(msg, "DLCX %u", trans_id);
break;
case MGCP_VERB_AUEP:
mandatory_mask = MGCP_AUEP_MANDATORY;
rc += msgb_printf(msg, "AUEP %u", trans_id);
break;
case MGCP_VERB_RSIP:
mandatory_mask = MGCP_RSIP_MANDATORY;
rc += msgb_printf(msg, "RSIP %u", trans_id);
break;
default:
LOGP(DLMGCP, LOGL_ERROR,
"Invalid command verb, can not generate MGCP message\n");
msgb_free(msg);
return NULL;
}
/* Check if mandatory fields are missing */
if (!((mgcp_msg->presence & mandatory_mask) == mandatory_mask)) {
LOGP(DLMGCP, LOGL_ERROR,
"One or more missing mandatory fields, can not generate MGCP message\n");
msgb_free(msg);
return NULL;
}
/* Add endpoint name */
if (mgcp_msg->presence & MGCP_MSG_PRESENCE_ENDPOINT) {
if (strlen(mgcp_msg->endpoint) <= 0) {
LOGP(DLMGCP, LOGL_ERROR,
"Empty endpoint name, can not generate MGCP message\n");
msgb_free(msg);
return NULL;
}
if (strstr(mgcp_msg->endpoint, "@") == NULL) {
LOGP(DLMGCP, LOGL_ERROR,
"Endpoint name (%s) lacks separator (@), can not generate MGCP message\n",
mgcp_msg->endpoint);
msgb_free(msg);
}
rc += msgb_printf(msg, " %s", mgcp_msg->endpoint);
}
/* Add protocol version */
rc += msgb_printf(msg, " MGCP 1.0\r\n");
/* Add call id */
if (mgcp_msg->presence & MGCP_MSG_PRESENCE_CALL_ID)
rc += msgb_printf(msg, "C: %x\r\n", mgcp_msg->call_id);
/* Add connection id */
if (mgcp_msg->presence & MGCP_MSG_PRESENCE_CONN_ID) {
if (strlen(mgcp_msg->conn_id) <= 0) {
LOGP(DLMGCP, LOGL_ERROR,
"Empty connection id, can not generate MGCP message\n");
msgb_free(msg);
return NULL;
}
rc += msgb_printf(msg, "I: %s\r\n", mgcp_msg->conn_id);
}
/* Add local connection options */
if (mgcp_msg->verb == MGCP_VERB_CRCX)
rc += msgb_printf(msg, "L: p:20, a:AMR, nt:IN\r\n");
/* Add mode */
if (mgcp_msg->presence & MGCP_MSG_PRESENCE_CONN_MODE)
rc +=
msgb_printf(msg, "M: %s\r\n",
mgcp_client_cmode_name(mgcp_msg->conn_mode));
/* Add SDP body */
if (mgcp_msg->presence & MGCP_MSG_PRESENCE_AUDIO_IP
&& mgcp_msg->presence & MGCP_MSG_PRESENCE_AUDIO_PORT) {
/* Add separator to mark the beginning of the SDP block */
rc += msgb_printf(msg, "\r\n");
/* Add SDP protocol version */
rc += msgb_printf(msg, "v=0\r\n");
/* Determine local IP-Address */
if (osmo_sock_local_ip(local_ip, mgcp->actual.remote_addr) < 0) {
LOGP(DLMGCP, LOGL_ERROR,
"Could not determine local IP-Address!\n");
msgb_free(msg);
return NULL;
}
/* Add owner/creator (SDP) */
rc += msgb_printf(msg, "o=- %x 23 IN IP4 %s\r\n",
mgcp_msg->call_id, local_ip);
/* Add session name (none) */
rc += msgb_printf(msg, "s=-\r\n");
/* Add RTP address and port */
if (mgcp_msg->audio_port == 0) {
LOGP(DLMGCP, LOGL_ERROR,
"Invalid port number, can not generate MGCP message\n");
msgb_free(msg);
return NULL;
}
if (strlen(mgcp_msg->audio_ip) <= 0) {
LOGP(DLMGCP, LOGL_ERROR,
"Empty ip address, can not generate MGCP message\n");
msgb_free(msg);
return NULL;
}
rc += msgb_printf(msg, "c=IN IP4 %s\r\n", mgcp_msg->audio_ip);
/* Add time description, active time (SDP) */
rc += msgb_printf(msg, "t=0 0\r\n");
rc +=
msgb_printf(msg, "m=audio %u RTP/AVP 255\r\n",
mgcp_msg->audio_port);
}
if (rc != 0) {
LOGP(DLMGCP, LOGL_ERROR,
"message buffer to small, can not generate MGCP message\n");
msgb_free(msg);
msg = NULL;
}
return msg;
}
/*! Retrieve the MGCP transaction ID from a msgb generated by mgcp_msg_gen()
* \param[in] msg message buffer
* \returns Transaction id. */
mgcp_trans_id_t mgcp_msg_trans_id(struct msgb *msg)
{
return (mgcp_trans_id_t)msg->cb[MSGB_CB_MGCP_TRANS_ID];
}
/*! Get the configuration parameters a given MGCP client instance
* \param[in] mgcp MGCP client descriptor.
* \returns configuration */
struct mgcp_client_conf *mgcp_client_conf_actual(struct mgcp_client *mgcp)
{
return &mgcp->actual;
}
const struct value_string mgcp_client_connection_mode_strs[] = {
{ MGCP_CONN_NONE, "none" },
{ MGCP_CONN_RECV_SEND, "sendrecv" },
{ MGCP_CONN_SEND_ONLY, "sendonly" },
{ MGCP_CONN_RECV_ONLY, "recvonly" },
{ MGCP_CONN_LOOPBACK, "loopback" },
{ 0, NULL }
};
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