| /* 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> |
| |
| /*! 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:%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:%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:%x conn:%s\n", |
| ENDPOINT_NUMBER(endp), mgcp_conn_dump(conn)); |
| |
| LOGP(DLMGCP, LOGL_DEBUG, |
| "endpoint:%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:%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; |
| |
| 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; |
| } |
| |
| return &tcfg->endpoints[endp]; |
| } |
| |
| /* 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) |
| { |
| char *endptr = NULL; |
| unsigned int gw = INT_MAX; |
| |
| if (strncmp(mgcp, "ds/e1", 5) == 0) |
| return find_e1_endpoint(cfg, mgcp); |
| |
| gw = strtoul(mgcp, &endptr, 10); |
| if (gw > 0 && gw < cfg->trunk.number_endpoints && endptr[0] == '@') |
| return &cfg->trunk.endpoints[gw]; |
| |
| LOGP(DLMGCP, LOGL_ERROR, "Not able to find the endpoint: '%s'\n", mgcp); |
| 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; |
| |
| /*! 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); |
| if (!pdata->endp) { |
| LOGP(DLMGCP, LOGL_ERROR, |
| "Unable to find Endpoint `%s'\n", elem); |
| return -1; |
| } |
| break; |
| case 2: |
| if (strcmp("MGCP", elem)) { |
| LOGP(DLMGCP, LOGL_ERROR, |
| "MGCP header parsing error\n"); |
| return -1; |
| } |
| break; |
| case 3: |
| if (strcmp("1.0", elem)) { |
| LOGP(DLMGCP, LOGL_ERROR, "MGCP version `%s' " |
| "not supported\n", elem); |
| return -1; |
| } |
| break; |
| } |
| i++; |
| } |
| |
| if (i != 4) { |
| LOGP(DLMGCP, LOGL_ERROR, "MGCP status line too short.\n"); |
| pdata->trans = "000000"; |
| pdata->endp = NULL; |
| return -1; |
| } |
| |
| 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; |
| if (!callid) |
| return -1; |
| if (!endp->callid) |
| return -1; |
| |
| if (strcmp(endp->callid, callid) != 0) { |
| LOGP(DLMGCP, LOGL_ERROR, |
| "endpoint:%x CallIDs does not match '%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 1 when connection id seems plausible, 0 on error */ |
| int mgcp_verify_ci(struct mgcp_endpoint *endp, const char *ci) |
| { |
| uint32_t id; |
| |
| if (!endp) |
| return -1; |
| |
| id = strtoul(ci, NULL, 10); |
| |
| if (mgcp_conn_get(endp, id)) |
| return 0; |
| |
| LOGP(DLMGCP, LOGL_ERROR, |
| "endpoint:%x No connection found under ConnectionIdentifier %u\n", |
| ENDPOINT_NUMBER(endp), id); |
| |
| return -1; |
| } |
| |
| /*! 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; |
| } |
| |
| /*! Parse CI from a given string. |
| * \param[out] caller provided memory to store the result |
| * \param{in] string containing the connection id |
| * \returns 0 on success, -1 on error */ |
| int mgcp_parse_ci(uint32_t *conn_id, const char *ci) |
| { |
| |
| OSMO_ASSERT(conn_id); |
| |
| if (!ci) |
| return -1; |
| |
| *conn_id = strtoul(ci, NULL, 10); |
| |
| return 0; |
| } |