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osmo-mgw/src/libosmo-mgcp/mgcp_msg.c

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/* A Media Gateway Control Protocol Media Gateway: RFC 3435 */
/* Message parser/generator utilities */
/*
* (C) 2009-2012 by Holger Hans Peter Freyther <zecke@selfish.org>
* (C) 2009-2012 by On-Waves
* (C) 2017 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 <limits.h>
#include <osmocom/mgcp/mgcp_internal.h>
#include <osmocom/mgcp/mgcp_common.h>
#include <osmocom/mgcp/mgcp_msg.h>
#include <osmocom/mgcp/mgcp_conn.h>
#include <osmocom/mgcp/mgcp_endp.h>
/*! Display an mgcp message on the log output.
* \param[in] message mgcp message string
* \param[in] len message mgcp message string length
* \param[in] preamble string to display in logtext in front of each line */
void mgcp_disp_msg(unsigned char *message, unsigned int len, char *preamble)
{
unsigned char line[80];
unsigned char *ptr;
unsigned int consumed = 0;
unsigned int consumed_line = 0;
unsigned int line_count = 0;
if (!log_check_level(DLMGCP, LOGL_DEBUG))
return;
while (1) {
memset(line, 0, sizeof(line));
ptr = line;
consumed_line = 0;
do {
if (*message != '\n' && *message != '\r') {
*ptr = *message;
ptr++;
}
message++;
consumed++;
consumed_line++;
} while (*message != '\n' && consumed < len
&& consumed_line < sizeof(line));
if (strlen((const char *)line)) {
LOGP(DLMGCP, LOGL_DEBUG, "%s: line #%02u: %s\n",
preamble, line_count, line);
line_count++;
}
if (consumed >= len)
return;
}
}
/*! Parse connection mode.
* \param[in] mode as string (recvonly, sendrecv, sendonly or loopback)
* \param[in] endp pointer to endpoint (only used for log output)
* \param[out] associated connection to be modified accordingly
* \returns 0 on success, -1 on error */
int mgcp_parse_conn_mode(const char *mode, struct mgcp_endpoint *endp,
struct mgcp_conn *conn)
{
int ret = 0;
if (!mode) {
LOGP(DLMGCP, LOGL_ERROR,
"endpoint:0x%x missing connection mode\n",
ENDPOINT_NUMBER(endp));
return -1;
}
if (!conn)
return -1;
if (!endp)
return -1;
if (strcmp(mode, "recvonly") == 0)
conn->mode = MGCP_CONN_RECV_ONLY;
else if (strcmp(mode, "sendrecv") == 0)
conn->mode = MGCP_CONN_RECV_SEND;
else if (strcmp(mode, "sendonly") == 0)
conn->mode = MGCP_CONN_SEND_ONLY;
else if (strcmp(mode, "loopback") == 0)
conn->mode = MGCP_CONN_LOOPBACK;
else {
LOGP(DLMGCP, LOGL_ERROR,
"endpoint:0x%x unknown connection mode: '%s'\n",
ENDPOINT_NUMBER(endp), mode);
ret = -1;
}
/* Special handling für RTP connections */
if (conn->type == MGCP_CONN_TYPE_RTP) {
conn->u.rtp.end.output_enabled =
conn->mode & MGCP_CONN_SEND_ONLY ? 1 : 0;
}
LOGP(DLMGCP, LOGL_DEBUG,
"endpoint:0x%x conn:%s\n",
ENDPOINT_NUMBER(endp), mgcp_conn_dump(conn));
LOGP(DLMGCP, LOGL_DEBUG,
"endpoint:0x%x connection mode '%s' %d\n",
ENDPOINT_NUMBER(endp), mode, conn->mode);
/* Special handling für RTP connections */
if (conn->type == MGCP_CONN_TYPE_RTP) {
LOGP(DLMGCP, LOGL_DEBUG, "endpoint:0x%x output_enabled %d\n",
ENDPOINT_NUMBER(endp), conn->u.rtp.end.output_enabled);
}
/* The VTY might change the connection mode at any time, so we have
* to hold a copy of the original connection mode */
conn->mode_orig = conn->mode;
return ret;
}
/* We have a null terminated string with the endpoint name here. We only
* support two kinds. Simple ones as seen on the BSC level and the ones
* seen on the trunk side. (helper function for find_endpoint()) */
static struct mgcp_endpoint *find_e1_endpoint(struct mgcp_config *cfg,
const char *mgcp)
{
char *rest = NULL;
struct mgcp_trunk_config *tcfg;
int trunk, endp;
struct mgcp_endpoint *endp_ptr;
trunk = strtoul(mgcp + 6, &rest, 10);
if (rest == NULL || rest[0] != '/' || trunk < 1) {
LOGP(DLMGCP, LOGL_ERROR, "Wrong trunk name '%s'\n", mgcp);
return NULL;
}
endp = strtoul(rest + 1, &rest, 10);
if (rest == NULL || rest[0] != '@') {
LOGP(DLMGCP, LOGL_ERROR, "Wrong endpoint name '%s'\n", mgcp);
return NULL;
}
/* signalling is on timeslot 1 */
if (endp == 1)
return NULL;
tcfg = mgcp_trunk_num(cfg, trunk);
if (!tcfg) {
LOGP(DLMGCP, LOGL_ERROR, "The trunk %d is not declared.\n",
trunk);
return NULL;
}
if (!tcfg->endpoints) {
LOGP(DLMGCP, LOGL_ERROR,
"Endpoints of trunk %d not allocated.\n", trunk);
return NULL;
}
if (endp < 1 || endp >= tcfg->number_endpoints) {
LOGP(DLMGCP, LOGL_ERROR, "Failed to find endpoint '%s'\n",
mgcp);
return NULL;
}
endp_ptr = &tcfg->endpoints[endp];
endp_ptr->wildcarded_req = false;
return endp_ptr;
}
/* Find an endpoint that is not in use. Do this by going through the endpoint
* array, check the callid. A callid nullpointer indicates that the endpoint
* is free */
static struct mgcp_endpoint *find_free_endpoint(struct mgcp_endpoint *endpoints,
unsigned int number_endpoints)
{
struct mgcp_endpoint *endp;
unsigned int i;
for (i = 0; i < number_endpoints; i++) {
if (endpoints[i].callid == NULL) {
endp = &endpoints[i];
LOGP(DLMGCP, LOGL_DEBUG,
"endpoint:0x%x found free endpoint\n",
ENDPOINT_NUMBER(endp));
endp->wildcarded_req = true;
return endp;
}
}
LOGP(DLMGCP, LOGL_ERROR, "Not able to find a free endpoint\n");
return NULL;
}
/* Check if the domain name, which is supplied with the endpoint name
* matches the configuration. */
static int check_domain_name(struct mgcp_config *cfg, const char *mgcp)
{
char *domain_to_check;
domain_to_check = strstr(mgcp, "@");
if (!domain_to_check)
return -EINVAL;
/* Accept any domain if configured as "*" */
if (!strcmp(cfg->domain, "*"))
return 0;
if (strcmp(domain_to_check+1, cfg->domain) != 0)
return -EINVAL;
return 0;
}
/* Search the endpoint pool for the endpoint that had been selected via the
* MGCP message (helper function for mgcp_analyze_header()) */
static struct mgcp_endpoint *find_endpoint(struct mgcp_config *cfg,
const char *mgcp,
int *cause)
{
char *endptr = NULL;
unsigned int gw = INT_MAX;
const char *endpoint_number_str;
struct mgcp_endpoint *endp;
*cause = 0;
/* Check if the domainname in the request is correct */
if (check_domain_name(cfg, mgcp)) {
LOGP(DLMGCP, LOGL_ERROR, "Wrong domain name '%s'\n", mgcp);
*cause = -500;
return NULL;
}
/* Check if the E1 trunk is requested */
if (strncmp(mgcp, "ds/e1", 5) == 0) {
endp = find_e1_endpoint(cfg, mgcp);
if (!endp)
*cause = -500;
return endp;
}
/* Check if the virtual trunk is addressed (new, correct way with prefix) */
if (strncmp
(mgcp, MGCP_ENDPOINT_PREFIX_VIRTUAL_TRUNK,
strlen(MGCP_ENDPOINT_PREFIX_VIRTUAL_TRUNK)) == 0) {
endpoint_number_str =
mgcp + strlen(MGCP_ENDPOINT_PREFIX_VIRTUAL_TRUNK);
if (endpoint_number_str[0] == '*') {
endp = find_free_endpoint(cfg->trunk.endpoints,
cfg->trunk.number_endpoints);
if (!endp)
*cause = -403;
return endp;
}
gw = strtoul(endpoint_number_str, &endptr, 16);
if (gw < cfg->trunk.number_endpoints && endptr[0] == '@') {
endp = &cfg->trunk.endpoints[gw];
endp->wildcarded_req = false;
return endp;
}
}
/* Deprecated method without prefix */
LOGP(DLMGCP, LOGL_NOTICE,
"Addressing virtual trunk without prefix (deprecated), please use %s: '%s'\n",
MGCP_ENDPOINT_PREFIX_VIRTUAL_TRUNK, mgcp);
gw = strtoul(mgcp, &endptr, 16);
if (gw < cfg->trunk.number_endpoints && endptr[0] == '@') {
endp = &cfg->trunk.endpoints[gw];
endp->wildcarded_req = false;
return endp;
}
LOGP(DLMGCP, LOGL_ERROR, "Not able to find the endpoint: '%s'\n", mgcp);
*cause = -500;
return NULL;
}
/*! Analyze and parse the the hader of an MGCP messeage string.
* \param[out] pdata caller provided memory to store the parsing results
* \param[in] data mgcp message string
* \returns when the status line was complete and transaction_id and
* endp out parameters are set, -1 on error */
int mgcp_parse_header(struct mgcp_parse_data *pdata, char *data)
{
int i = 0;
char *elem, *save = NULL;
int cause;
/*! This function will parse the header part of the received
* MGCP message. The parsing results are stored in pdata.
* The function will also automatically search the pool with
* available endpoints in order to find an endpoint that matches
* the endpoint string in in the header */
OSMO_ASSERT(data);
pdata->trans = "000000";
for (elem = strtok_r(data, " ", &save); elem;
elem = strtok_r(NULL, " ", &save)) {
switch (i) {
case 0:
pdata->trans = elem;
break;
case 1:
pdata->endp = find_endpoint(pdata->cfg, elem, &cause);
if (!pdata->endp) {
LOGP(DLMGCP, LOGL_ERROR,
"Unable to find Endpoint `%s'\n", elem);
OSMO_ASSERT(cause < 0);
return cause;
}
break;
case 2:
if (strcmp("MGCP", elem)) {
LOGP(DLMGCP, LOGL_ERROR,
"MGCP header parsing error\n");
return -510;
}
break;
case 3:
if (strcmp("1.0", elem)) {
LOGP(DLMGCP, LOGL_ERROR, "MGCP version `%s' "
"not supported\n", elem);
return -528;
}
break;
}
i++;
}
if (i != 4) {
LOGP(DLMGCP, LOGL_ERROR, "MGCP status line too short.\n");
pdata->trans = "000000";
pdata->endp = NULL;
return -510;
}
return 0;
}
/*! Extract OSMUX CID from an MGCP parameter line (string).
* \param[in] line single parameter line from the MGCP message
* \returns OSMUX CID, -1 on error */
int mgcp_parse_osmux_cid(const char *line)
{
int osmux_cid;
if (sscanf(line + 2, "Osmux: %u", &osmux_cid) != 1)
return -1;
if (osmux_cid > OSMUX_CID_MAX) {
LOGP(DLMGCP, LOGL_ERROR, "Osmux ID too large: %u > %u\n",
osmux_cid, OSMUX_CID_MAX);
return -1;
}
LOGP(DLMGCP, LOGL_DEBUG, "bsc-nat offered Osmux CID %u\n", osmux_cid);
return osmux_cid;
}
/*! Check MGCP parameter line (string) for plausibility.
* \param[in] endp pointer to endpoint (only used for log output)
* \param[in] line single parameter line from the MGCP message
* \returns 1 when line seems plausible, 0 on error */
int mgcp_check_param(const struct mgcp_endpoint *endp, const char *line)
{
const size_t line_len = strlen(line);
if (line[0] != '\0' && line_len < 2) {
LOGP(DLMGCP, LOGL_ERROR,
"Wrong MGCP option format: '%s' on 0x%x\n",
line, ENDPOINT_NUMBER(endp));
return 0;
}
/* FIXME: A couple more checks wouldn't hurt... */
return 1;
}
/*! Check if the specified callid seems plausible.
* \param[in] endp pointer to endpoint
* \param{in] callid to verify
* \returns 1 when callid seems plausible, 0 on error */
int mgcp_verify_call_id(struct mgcp_endpoint *endp, const char *callid)
{
/*! This function compares the supplied callid with the called that is
* stored in the endpoint structure. */
if (!endp)
return -1;
/* Accept any CallID for "X-Osmo-IGN: C" */
if (endp->x_osmo_ign & MGCP_X_OSMO_IGN_CALLID)
return 0;
if (!callid)
return -1;
if (!endp->callid)
return -1;
if (strcmp(endp->callid, callid) != 0) {
LOGP(DLMGCP, LOGL_ERROR,
"endpoint:0x%x CallIDs mismatch: '%s' != '%s'\n",
ENDPOINT_NUMBER(endp), endp->callid, callid);
return -1;
}
return 0;
}
/*! Check if the specified connection id seems plausible.
* \param[in] endp pointer to endpoint
* \param{in] connection id to verify
* \returns 0 when connection id is valid and exists, an RFC3435 error code on error.
*/
int mgcp_verify_ci(struct mgcp_endpoint *endp, const char *conn_id)
{
/* For invalid conn_ids, return 510 "The transaction could not be executed, because some
* unspecified protocol error was detected." */
/* Check for null identifiers */
if (!conn_id) {
LOGP(DLMGCP, LOGL_ERROR,
"endpoint:0x%x invalid ConnectionIdentifier (missing)\n",
ENDPOINT_NUMBER(endp));
return 510;
}
/* Check for empty connection identifiers */
if (strlen(conn_id) == 0) {
LOGP(DLMGCP, LOGL_ERROR,
"endpoint:0x%x invalid ConnectionIdentifier (empty)\n",
ENDPOINT_NUMBER(endp));
return 510;
}
/* Check for over long connection identifiers */
if (strlen(conn_id) > (MGCP_CONN_ID_MAXLEN-1)) {
LOGP(DLMGCP, LOGL_ERROR,
"endpoint:0x%x invalid ConnectionIdentifier (too long: %zu > %d) 0x%s\n",
ENDPOINT_NUMBER(endp), strlen(conn_id), MGCP_CONN_ID_MAXLEN-1, conn_id);
return 510;
}
/* Check if connection exists */
if (mgcp_conn_get(endp, conn_id))
return 0;
LOGP(DLMGCP, LOGL_ERROR,
"endpoint:0x%x no connection found under ConnectionIdentifier 0x%s\n",
ENDPOINT_NUMBER(endp), conn_id);
/* When the conn_id was not found, return error code 515 "The transaction refers to an incorrect
* connection-id (may have been already deleted)." */
return 515;
}
/*! Extract individual lines from MCGP message.
* \param[in] str MGCP message string, consisting of multiple lines
* \param{in] saveptr pointer to next line in str
* \returns line, NULL when done */
char *mgcp_strline(char *str, char **saveptr)
{
char *result;
/*! The function must be called with *str set to the input string
* for the first line. After that saveptr will be initalized.
* all consecutive lines are extracted by calling the function
* with str set to NULL. When done, the function will return NULL
* to indicate that all lines have been parsed. */
if (str)
*saveptr = str;
result = *saveptr;
if (*saveptr != NULL) {
*saveptr = strpbrk(*saveptr, "\r\n");
if (*saveptr != NULL) {
char *eos = *saveptr;
if ((*saveptr)[0] == '\r' && (*saveptr)[1] == '\n')
(*saveptr)++;
(*saveptr)++;
if ((*saveptr)[0] == '\0')
*saveptr = NULL;
*eos = '\0';
}
}
return result;
}
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