| /* A Media Gateway Control Protocol Media Gateway: RFC 3435 */ |
| /* The protocol implementation */ |
| |
| /* |
| * (C) 2009-2010 by Holger Hans Peter Freyther <zecke@selfish.org> |
| * (C) 2009-2010 by On-Waves |
| * 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, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| */ |
| |
| #include <string.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <endian.h> |
| #include <errno.h> |
| |
| #include <sys/socket.h> |
| #include <arpa/inet.h> |
| |
| #include <osmocore/msgb.h> |
| #include <osmocore/select.h> |
| |
| #include <openbsc/debug.h> |
| #include <openbsc/mgcp.h> |
| #include <openbsc/mgcp_internal.h> |
| |
| #warning "Make use of the rtp proxy code" |
| |
| /* according to rtp_proxy.c RFC 3550 */ |
| struct rtp_hdr { |
| #if __BYTE_ORDER == __LITTLE_ENDIAN |
| u_int8_t csrc_count:4, |
| extension:1, |
| padding:1, |
| version:2; |
| u_int8_t payload_type:7, |
| marker:1; |
| #elif __BYTE_ORDER == __BIG_ENDIAN |
| u_int8_t version:2, |
| padding:1, |
| extension:1, |
| csrc_count:4; |
| u_int8_t marker:1, |
| payload_type:7; |
| #endif |
| u_int16_t sequence; |
| u_int32_t timestamp; |
| u_int32_t ssrc; |
| } __attribute__((packed)); |
| |
| |
| enum { |
| DEST_NETWORK = 0, |
| DEST_BTS = 1, |
| }; |
| |
| enum { |
| PROTO_RTP, |
| PROTO_RTCP, |
| }; |
| |
| #define DUMMY_LOAD 0x23 |
| |
| |
| static int udp_send(int fd, struct in_addr *addr, int port, char *buf, int len) |
| { |
| struct sockaddr_in out; |
| out.sin_family = AF_INET; |
| out.sin_port = port; |
| memcpy(&out.sin_addr, addr, sizeof(*addr)); |
| |
| return sendto(fd, buf, len, 0, (struct sockaddr *)&out, sizeof(out)); |
| } |
| |
| int mgcp_send_dummy(struct mgcp_endpoint *endp) |
| { |
| static char buf[] = { DUMMY_LOAD }; |
| |
| return udp_send(endp->local_rtp.fd, &endp->remote, |
| endp->net_rtp, buf, 1); |
| } |
| |
| static void patch_payload(int payload, char *data, int len) |
| { |
| struct rtp_hdr *rtp_hdr; |
| |
| if (len < sizeof(*rtp_hdr)) |
| return; |
| |
| if (payload < 0) |
| return; |
| |
| rtp_hdr = (struct rtp_hdr *) data; |
| rtp_hdr->payload_type = payload; |
| } |
| |
| /* |
| * There is data coming. We will have to figure out if it |
| * came from the BTS or the MediaGateway of the MSC. On top |
| * of that we need to figure out if it was RTP or RTCP. |
| * |
| * Currently we do not communicate with the BSC so we have |
| * no idea where the BTS is listening for RTP and need to |
| * do the classic routing trick. Wait for the first packet |
| * from the BTS and then go ahead. |
| */ |
| static int rtp_data_cb(struct bsc_fd *fd, unsigned int what) |
| { |
| char buf[4096]; |
| struct sockaddr_in addr; |
| socklen_t slen = sizeof(addr); |
| struct mgcp_endpoint *endp; |
| struct mgcp_config *cfg; |
| int rc, dest, proto; |
| |
| endp = (struct mgcp_endpoint *) fd->data; |
| cfg = endp->cfg; |
| |
| rc = recvfrom(fd->fd, &buf, sizeof(buf), 0, |
| (struct sockaddr *) &addr, &slen); |
| if (rc < 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to receive message on: 0x%x errno: %d/%s\n", |
| ENDPOINT_NUMBER(endp), errno, strerror(errno)); |
| return -1; |
| } |
| |
| /* do not forward aynthing... maybe there is a packet from the bts */ |
| if (endp->ci == CI_UNUSED) |
| return -1; |
| |
| /* |
| * Figure out where to forward it to. This code assumes that we |
| * have received the Connection Modify and know who is a legitimate |
| * partner. According to the spec we could attempt to forward even |
| * after the Create Connection but we will not as we are not really |
| * able to tell if this is legitimate. |
| */ |
| #warning "Slight spec violation. With connection mode recvonly we should attempt to forward." |
| dest = memcmp(&addr.sin_addr, &endp->remote, sizeof(addr.sin_addr)) == 0 && |
| (endp->net_rtp == addr.sin_port || endp->net_rtcp == addr.sin_port) |
| ? DEST_BTS : DEST_NETWORK; |
| proto = fd == &endp->local_rtp ? PROTO_RTP : PROTO_RTCP; |
| |
| /* We have no idea who called us, maybe it is the BTS. */ |
| if (dest == DEST_NETWORK && (endp->bts_rtp == 0 || cfg->forward_ip)) { |
| /* it was the BTS... */ |
| if (!cfg->bts_ip |
| || memcmp(&addr.sin_addr, &cfg->bts_in, sizeof(cfg->bts_in)) == 0 |
| || memcmp(&addr.sin_addr, &endp->bts, sizeof(endp->bts)) == 0) { |
| if (fd == &endp->local_rtp) { |
| endp->bts_rtp = addr.sin_port; |
| } else { |
| endp->bts_rtcp = addr.sin_port; |
| } |
| |
| endp->bts = addr.sin_addr; |
| LOGP(DMGCP, LOGL_NOTICE, "Found BTS for endpoint: 0x%x on port: %d/%d of %s\n", |
| ENDPOINT_NUMBER(endp), ntohs(endp->bts_rtp), ntohs(endp->bts_rtcp), |
| inet_ntoa(addr.sin_addr)); |
| |
| } |
| } |
| |
| /* throw away the dummy message */ |
| if (rc == 1 && buf[0] == DUMMY_LOAD) { |
| LOGP(DMGCP, LOGL_NOTICE, "Filtered dummy on 0x%x\n", |
| ENDPOINT_NUMBER(endp)); |
| return 0; |
| } |
| |
| /* do this before the loop handling */ |
| if (dest == DEST_NETWORK) |
| ++endp->in_bts; |
| else |
| ++endp->in_remote; |
| |
| /* For loop toggle the destination and then dispatch. */ |
| if (cfg->audio_loop) |
| dest = !dest; |
| |
| if (dest == DEST_NETWORK) { |
| patch_payload(endp->net_payload_type, buf, rc); |
| return udp_send(fd->fd, &endp->remote, |
| proto == PROTO_RTP ? endp->net_rtp : endp->net_rtcp, |
| buf, rc); |
| } else { |
| patch_payload(endp->bts_payload_type, buf, rc); |
| return udp_send(fd->fd, &endp->bts, |
| proto == PROTO_RTP ? endp->bts_rtp : endp->bts_rtcp, |
| buf, rc); |
| } |
| } |
| |
| static int create_bind(const char *source_addr, struct bsc_fd *fd, int port) |
| { |
| struct sockaddr_in addr; |
| int on = 1; |
| |
| fd->fd = socket(AF_INET, SOCK_DGRAM, 0); |
| if (fd->fd < 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to create UDP port.\n"); |
| return -1; |
| } |
| |
| setsockopt(fd->fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); |
| memset(&addr, 0, sizeof(addr)); |
| addr.sin_family = AF_INET; |
| addr.sin_port = htons(port); |
| inet_aton(source_addr, &addr.sin_addr); |
| |
| if (bind(fd->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| static int bind_rtp(struct mgcp_endpoint *endp) |
| { |
| struct mgcp_config *cfg = endp->cfg; |
| |
| if (create_bind(cfg->source_addr, &endp->local_rtp, endp->rtp_port) != 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to create RTP port: %s:%d on 0x%x\n", |
| cfg->source_addr, endp->rtp_port, ENDPOINT_NUMBER(endp)); |
| goto cleanup0; |
| } |
| |
| if (create_bind(cfg->source_addr, &endp->local_rtcp, endp->rtp_port + 1) != 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to create RTCP port: %s:%d on 0x%x\n", |
| cfg->source_addr, endp->rtp_port + 1, ENDPOINT_NUMBER(endp)); |
| goto cleanup1; |
| } |
| |
| endp->local_rtp.cb = rtp_data_cb; |
| endp->local_rtp.data = endp; |
| endp->local_rtp.when = BSC_FD_READ; |
| if (bsc_register_fd(&endp->local_rtp) != 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to register RTP port %d on 0x%x\n", |
| endp->rtp_port, ENDPOINT_NUMBER(endp)); |
| goto cleanup2; |
| } |
| |
| endp->local_rtcp.cb = rtp_data_cb; |
| endp->local_rtcp.data = endp; |
| endp->local_rtcp.when = BSC_FD_READ; |
| if (bsc_register_fd(&endp->local_rtcp) != 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to register RTCP port %d on 0x%x\n", |
| endp->rtp_port + 1, ENDPOINT_NUMBER(endp)); |
| goto cleanup3; |
| } |
| |
| return 0; |
| |
| cleanup3: |
| bsc_unregister_fd(&endp->local_rtp); |
| cleanup2: |
| close(endp->local_rtcp.fd); |
| endp->local_rtcp.fd = -1; |
| cleanup1: |
| close(endp->local_rtp.fd); |
| endp->local_rtp.fd = -1; |
| cleanup0: |
| return -1; |
| } |
| |
| int mgcp_bind_rtp_port(struct mgcp_endpoint *endp, int rtp_port) |
| { |
| endp->rtp_port = rtp_port; |
| return bind_rtp(endp); |
| } |