| /* 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.h> |
| #include <osmocom/mgcp/osmux.h> |
| #include <osmocom/mgcp/mgcp_protocol.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> |
| #include <osmocom/mgcp/mgcp_trunk.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) { |
| LOGPCONN(conn, DLMGCP, LOGL_ERROR, |
| "missing connection mode\n"); |
| return -1; |
| } |
| if (!conn) |
| return -1; |
| if (!endp) |
| return -1; |
| |
| if (strcasecmp(mode, "recvonly") == 0) |
| conn->mode = MGCP_CONN_RECV_ONLY; |
| else if (strcasecmp(mode, "sendrecv") == 0) |
| conn->mode = MGCP_CONN_RECV_SEND; |
| else if (strcasecmp(mode, "sendonly") == 0) |
| conn->mode = MGCP_CONN_SEND_ONLY; |
| else if (strcasecmp(mode, "loopback") == 0) |
| conn->mode = MGCP_CONN_LOOPBACK; |
| else { |
| LOGPCONN(conn, DLMGCP, LOGL_ERROR, |
| "unknown connection mode: '%s'\n", mode); |
| ret = -1; |
| } |
| |
| /* Special handling for RTP connections */ |
| if (conn->type == MGCP_CONN_TYPE_RTP) { |
| conn->u.rtp.end.output_enabled = !!(conn->mode & MGCP_CONN_SEND_ONLY); |
| } |
| |
| LOGPENDP(endp, DLMGCP, LOGL_DEBUG, "conn:%s\n", mgcp_conn_dump(conn)); |
| |
| LOGPCONN(conn, DLMGCP, LOGL_DEBUG, "connection mode '%s' %d\n", |
| mode, conn->mode); |
| |
| /* Special handling für RTP connections */ |
| if (conn->type == MGCP_CONN_TYPE_RTP) { |
| LOGPCONN(conn, DLMGCP, LOGL_DEBUG, "output_enabled %u\n", |
| 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; |
| } |
| |
| /*! 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 0 when the status line was complete and parseable, negative (MGCP |
| * cause code) 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. */ |
| |
| OSMO_ASSERT(data); |
| |
| for (elem = strtok_r(data, " ", &save); elem; |
| elem = strtok_r(NULL, " ", &save)) { |
| switch (i) { |
| case 0: |
| pdata->trans = elem; |
| break; |
| case 1: |
| pdata->epname = elem; |
| break; |
| case 2: |
| if (strcasecmp("MGCP", elem)) { |
| LOGP(DLMGCP, LOGL_ERROR, |
| "MGCP header parsing error\n"); |
| return -510; |
| } |
| break; |
| case 3: |
| if (strcmp("1.0", elem)) |
| return -528; |
| break; |
| } |
| i++; |
| } |
| |
| if (i != 4) { |
| LOGP(DLMGCP, LOGL_ERROR, "MGCP status line too short.\n"); |
| 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 wildcard, -2 on error */ |
| int mgcp_parse_osmux_cid(const char *line) |
| { |
| int osmux_cid; |
| |
| |
| if (strcasecmp(line + 2, "Osmux: *") == 0) { |
| LOGP(DLMGCP, LOGL_DEBUG, "Parsed wilcard Osmux CID\n"); |
| return -1; |
| } |
| |
| if (sscanf(line + 2 + 7, "%u", &osmux_cid) != 1) { |
| LOGP(DLMGCP, LOGL_ERROR, "Failed parsing Osmux in MGCP msg line: %s\n", |
| line); |
| return -2; |
| } |
| |
| if (osmux_cid > OSMUX_CID_MAX) { |
| LOGP(DLMGCP, LOGL_ERROR, "Osmux ID too large: %u > %u\n", |
| osmux_cid, OSMUX_CID_MAX); |
| return -2; |
| } |
| 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, may be NULL) |
| * \param[in] trunk pointer to trunk (only used for log output, may be NULL if endp is not NULL) |
| * \param[in] line single parameter line from the MGCP message |
| * \returns true when line seems plausible, false on error */ |
| bool mgcp_check_param(const struct mgcp_endpoint *endp, struct mgcp_trunk *trunk, const char *line) |
| { |
| const size_t line_len = strlen(line); |
| if (line[0] != '\0' && line_len < 2) { |
| if (endp) |
| LOGPENDP(endp, DLMGCP, LOGL_NOTICE, "wrong MGCP option format: '%s'\n", line); |
| else |
| LOGPTRUNK(trunk, DLMGCP, LOGL_NOTICE, "wrong MGCP option format: '%s'\n", line); |
| return false; |
| } |
| |
| /* FIXME: A couple more checks wouldn't hurt... */ |
| |
| return true; |
| } |
| |
| /*! Check if the specified callid seems plausible. |
| * \param[in] endp pointer to endpoint |
| * \param{in] callid to verify |
| * \returns 0 when callid seems plausible, -1 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) { |
| LOGPENDP(endp, DLMGCP, LOGL_ERROR, |
| "CallIDs mismatch: '%s' != '%s'\n", |
| 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) { |
| LOGPENDP(endp, DLMGCP, LOGL_ERROR, |
| "invalid ConnectionIdentifier (missing)\n"); |
| return 510; |
| } |
| |
| /* Check for empty connection identifiers */ |
| if (strlen(conn_id) == 0) { |
| LOGPENDP(endp, DLMGCP, LOGL_ERROR, |
| "invalid ConnectionIdentifier (empty)\n"); |
| return 510; |
| } |
| |
| /* Check for over long connection identifiers */ |
| if (strlen(conn_id) > (MGCP_CONN_ID_MAXLEN-1)) { |
| LOGPENDP(endp, DLMGCP, LOGL_ERROR, |
| "invalid ConnectionIdentifier (too long: %zu > %d) 0x%s\n", |
| 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; |
| |
| LOGPENDP(endp, DLMGCP, LOGL_ERROR, |
| "no connection found under ConnectionIdentifier 0x%s\n", 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; |
| } |