aboutsummaryrefslogtreecommitdiffstats
path: root/openbsc/src/libmgcp/mgcp_network.c
blob: b814d98579c4e4bed818ac16b0c382feb71efb55 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
/* A Media Gateway Control Protocol Media Gateway: RFC 3435 */
/* The protocol implementation */

/*
 * (C) 2009-2011 by Holger Hans Peter Freyther <zecke@selfish.org>
 * (C) 2009-2011 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 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 <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>

#include <sys/socket.h>
#include <arpa/inet.h>

#include <osmocore/msgb.h>
#include <osmocore/select.h>

#include <openbsc/mgcp.h>
#include <openbsc/mgcp_internal.h>

#warning "Make use of the rtp proxy code"

/* attempt to determine byte order */
#include <sys/types.h>
#include <sys/param.h>
#include <limits.h>

#ifndef __BYTE_ORDER
#error "__BYTE_ORDER should be defined by someone"
#endif

/* according to rtp_proxy.c RFC 3550 */
struct rtp_hdr {
#if __BYTE_ORDER == __LITTLE_ENDIAN
	uint8_t  csrc_count:4,
		  extension:1,
		  padding:1,
		  version:2;
	uint8_t  payload_type:7,
		  marker:1;
#elif __BYTE_ORDER == __BIG_ENDIAN
	uint8_t  version:2,
		  padding:1,
		  extension:1,
		  csrc_count:4;
	uint8_t  marker:1,
		  payload_type:7;
#endif
	uint16_t sequence;
	uint32_t timestamp;
	uint32_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->net_end.rtp.fd, &endp->net_end.addr,
			endp->net_end.rtp_port, buf, 1);
}

static void patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *state,
			    int payload, struct sockaddr_in *addr, char *data, int len)
{
	uint16_t seq;
	uint32_t timestamp;
	struct rtp_hdr *rtp_hdr;

	if (len < sizeof(*rtp_hdr))
		return;

	rtp_hdr = (struct rtp_hdr *) data;
	seq = ntohs(rtp_hdr->sequence);
	timestamp = ntohl(rtp_hdr->timestamp);

	if (!state->initialized) {
		state->seq_no = seq - 1;
		state->ssrc = state->orig_ssrc = rtp_hdr->ssrc;
		state->initialized = 1;
		state->last_timestamp = timestamp;
	} else if (state->ssrc != rtp_hdr->ssrc) {
		state->ssrc = rtp_hdr->ssrc;
		state->seq_offset = (state->seq_no + 1) - seq;
		state->timestamp_offset = state->last_timestamp - timestamp;
		state->patch = endp->allow_patch;
		LOGP(DMGCP, LOGL_NOTICE,
			"The SSRC changed on 0x%x SSRC: %u offset: %d from %s:%d in %d\n",
			ENDPOINT_NUMBER(endp), state->ssrc, state->seq_offset,
			inet_ntoa(addr->sin_addr), ntohs(addr->sin_port), endp->conn_mode);
	}

	/* apply the offset and store it back to the packet */
	if (state->patch) {
		seq += state->seq_offset;
		rtp_hdr->sequence = htons(seq);
		rtp_hdr->ssrc = state->orig_ssrc;

		timestamp += state->timestamp_offset;
		rtp_hdr->timestamp = htonl(timestamp);
	}

	/* seq changed, now compare if we have lost something */
	if (state->seq_no + 1u != seq)
		state->lost_no = abs(seq - (state->seq_no + 1));
	state->seq_no = seq;

	state->last_timestamp = timestamp;

	if (payload < 0)
		return;

	rtp_hdr->payload_type = payload;
}

/*
 * The below code is for dispatching. We have a dedicated port for
 * the data coming from the net and one to discover the BTS.
 */
static int forward_data(int fd, struct mgcp_rtp_tap *tap, const char *buf, int len)
{
	if (!tap->enabled)
		return 0;

	return sendto(fd, buf, len, 0,
		      (struct sockaddr *)&tap->forward, sizeof(tap->forward));
}

static int send_transcoder(struct mgcp_rtp_end *end, struct mgcp_config *cfg,
			   int is_rtp, const char *buf, int len)
{
	int rc;
	int port;
	struct sockaddr_in addr;

	port = is_rtp ? end->rtp_port : end->rtcp_port;

	addr.sin_family = AF_INET;
	addr.sin_addr = cfg->transcoder_in;
	addr.sin_port = port;

	rc = sendto(is_rtp ?
		end->rtp.fd :
		end->rtcp.fd, buf, len, 0,
		(struct sockaddr *) &addr, sizeof(addr));

	if (rc != len)
		LOGP(DMGCP, LOGL_ERROR,
			"Failed to send data to the transcoder: %s\n",
			strerror(errno));

	return rc;
}

static int send_to(struct mgcp_endpoint *endp, int dest, int is_rtp,
		   struct sockaddr_in *addr, char *buf, int rc)
{
	struct mgcp_trunk_config *tcfg = endp->tcfg;
	/* For loop toggle the destination and then dispatch. */
	if (tcfg->audio_loop)
		dest = !dest;

	/* Loop based on the conn_mode, maybe undoing the above */
	if (endp->conn_mode == MGCP_CONN_LOOPBACK)
		dest = !dest;

	if (dest == DEST_NETWORK) {
		if (is_rtp) {
			patch_and_count(endp, &endp->bts_state,
					endp->net_end.payload_type,
					addr, buf, rc);
			forward_data(endp->net_end.rtp.fd,
				     &endp->taps[MGCP_TAP_NET_OUT], buf, rc);
			return udp_send(endp->net_end.rtp.fd, &endp->net_end.addr,
					endp->net_end.rtp_port, buf, rc);
		} else {
			return udp_send(endp->net_end.rtcp.fd, &endp->net_end.addr,
					endp->net_end.rtcp_port, buf, rc);
		}
	} else {
		if (is_rtp) {
			patch_and_count(endp, &endp->net_state,
					endp->bts_end.payload_type,
					addr, buf, rc);
			forward_data(endp->bts_end.rtp.fd,
				     &endp->taps[MGCP_TAP_BTS_OUT], buf, rc);
			return udp_send(endp->bts_end.rtp.fd, &endp->bts_end.addr,
					endp->bts_end.rtp_port, buf, rc);
		} else {
			return udp_send(endp->bts_end.rtcp.fd, &endp->bts_end.addr,
					endp->bts_end.rtcp_port, buf, rc);
		}
	}
}

static int recevice_from(struct mgcp_endpoint *endp, int fd, struct sockaddr_in *addr,
			 char *buf, int bufsize)
{
	int rc;
	socklen_t slen = sizeof(*addr);

	rc = recvfrom(fd, buf, bufsize, 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->allocated)
		return -1;

	#warning "Slight spec violation. With connection mode recvonly we should attempt to forward."

	return rc;
}

static int rtp_data_net(struct bsc_fd *fd, unsigned int what)
{
	char buf[4096];
	struct sockaddr_in addr;
	struct mgcp_endpoint *endp;
	int rc, proto;

	endp = (struct mgcp_endpoint *) fd->data;

	rc = recevice_from(endp, fd->fd, &addr, buf, sizeof(buf));
	if (rc <= 0)
		return -1;

	if (memcmp(&addr.sin_addr, &endp->net_end.addr, sizeof(addr.sin_addr)) != 0) {
		LOGP(DMGCP, LOGL_ERROR,
			"Data from wrong address %s on 0x%x\n",
			inet_ntoa(addr.sin_addr), ENDPOINT_NUMBER(endp));
		return -1;
	}

	if (endp->net_end.rtp_port != addr.sin_port &&
	    endp->net_end.rtcp_port != addr.sin_port) {
		LOGP(DMGCP, LOGL_ERROR,
			"Data from wrong source port %d on 0x%x\n",
			ntohs(addr.sin_port), ENDPOINT_NUMBER(endp));
		return -1;
	}

	/* throw away the dummy message */
	if (rc == 1 && buf[0] == DUMMY_LOAD) {
		LOGP(DMGCP, LOGL_NOTICE, "Filtered dummy from network on 0x%x\n",
			ENDPOINT_NUMBER(endp));
		return 0;
	}

	proto = fd == &endp->net_end.rtp ? PROTO_RTP : PROTO_RTCP;
	endp->net_end.packets += 1;

	forward_data(fd->fd, &endp->taps[MGCP_TAP_NET_IN], buf, rc);
	if (endp->is_transcoded)
		return send_transcoder(&endp->trans_net, endp->cfg, proto == PROTO_RTP, &buf[0], rc);
	else
		return send_to(endp, DEST_BTS, proto == PROTO_RTP, &addr, &buf[0], rc);
}

static void discover_bts(struct mgcp_endpoint *endp, int proto, struct sockaddr_in *addr)
{
	struct mgcp_config *cfg = endp->cfg;

	if (proto == PROTO_RTP && endp->bts_end.rtp_port == 0) {
		if (!cfg->bts_ip ||
		    memcmp(&addr->sin_addr,
			   &cfg->bts_in, sizeof(cfg->bts_in)) == 0 ||
		    memcmp(&addr->sin_addr,
			   &endp->bts_end.addr, sizeof(endp->bts_end.addr)) == 0) {

			endp->bts_end.rtp_port = addr->sin_port;
			endp->bts_end.addr = 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_end.rtp_port),
				ntohs(endp->bts_end.rtcp_port), inet_ntoa(addr->sin_addr));
		}
	} else if (proto == PROTO_RTCP && endp->bts_end.rtcp_port == 0) {
		if (memcmp(&endp->bts_end.addr, &addr->sin_addr,
				sizeof(endp->bts_end.addr)) == 0) {
			endp->bts_end.rtcp_port = addr->sin_port;
		}
	}
}

static int rtp_data_bts(struct bsc_fd *fd, unsigned int what)
{
	char buf[4096];
	struct sockaddr_in addr;
	struct mgcp_endpoint *endp;
	struct mgcp_config *cfg;
	int rc, proto;

	endp = (struct mgcp_endpoint *) fd->data;
	cfg = endp->cfg;

	rc = recevice_from(endp, fd->fd, &addr, buf, sizeof(buf));
	if (rc <= 0)
		return -1;

	proto = fd == &endp->bts_end.rtp ? PROTO_RTP : PROTO_RTCP;

	/* We have no idea who called us, maybe it is the BTS. */
	/* it was the BTS... */
	discover_bts(endp, proto, &addr);

	if (memcmp(&endp->bts_end.addr, &addr.sin_addr, sizeof(addr.sin_addr)) != 0) {
		LOGP(DMGCP, LOGL_ERROR,
			"Data from wrong bts %s on 0x%x\n",
			inet_ntoa(addr.sin_addr), ENDPOINT_NUMBER(endp));
		return -1;
	}

	if (endp->bts_end.rtp_port != addr.sin_port &&
	    endp->bts_end.rtcp_port != addr.sin_port) {
		LOGP(DMGCP, LOGL_ERROR,
			"Data from wrong bts source port %d on 0x%x\n",
			ntohs(addr.sin_port), ENDPOINT_NUMBER(endp));
		return -1;
	}

	/* throw away the dummy message */
	if (rc == 1 && buf[0] == DUMMY_LOAD) {
		LOGP(DMGCP, LOGL_NOTICE, "Filtered dummy from bts on 0x%x\n",
			ENDPOINT_NUMBER(endp));
		return 0;
	}

	/* do this before the loop handling */
	endp->bts_end.packets += 1;

	forward_data(fd->fd, &endp->taps[MGCP_TAP_BTS_IN], buf, rc);
	if (endp->is_transcoded)
		return send_transcoder(&endp->trans_bts, endp->cfg, proto == PROTO_RTP, &buf[0], rc);
	else
		return send_to(endp, DEST_NETWORK, proto == PROTO_RTP, &addr, &buf[0], rc);
}

static int rtp_data_transcoder(struct mgcp_rtp_end *end, struct mgcp_endpoint *_endp,
			      int dest, struct bsc_fd *fd)
{
	char buf[4096];
	struct sockaddr_in addr;
	struct mgcp_config *cfg;
	int rc, proto;

	cfg = _endp->cfg;
	rc = recevice_from(_endp, fd->fd, &addr, buf, sizeof(buf));
	if (rc <= 0)
		return -1;

	proto = fd == &end->rtp ? PROTO_RTP : PROTO_RTCP;

	if (memcmp(&addr.sin_addr, &cfg->transcoder_in, sizeof(addr.sin_addr)) != 0) {
		LOGP(DMGCP, LOGL_ERROR,
			"Data not coming from transcoder dest: %d %s on 0x%x\n",
			dest, inet_ntoa(addr.sin_addr), ENDPOINT_NUMBER(_endp));
		return -1;
	}

	if (end->rtp_port != addr.sin_port &&
	    end->rtcp_port != addr.sin_port) {
		LOGP(DMGCP, LOGL_ERROR,
			"Data from wrong transcoder dest %d source port %d on 0x%x\n",
			dest, ntohs(addr.sin_port), ENDPOINT_NUMBER(_endp));
		return -1;
	}

	/* throw away the dummy message */
	if (rc == 1 && buf[0] == DUMMY_LOAD) {
		LOGP(DMGCP, LOGL_NOTICE, "Filtered dummy from transcoder dest %d on 0x%x\n",
			dest, ENDPOINT_NUMBER(_endp));
		return 0;
	}

	end->packets += 1;
	return send_to(_endp, dest, proto == PROTO_RTP, &addr, &buf[0], rc);
}

static int rtp_data_trans_net(struct bsc_fd *fd, unsigned int what)
{
	struct mgcp_endpoint *endp;
	endp = (struct mgcp_endpoint *) fd->data;

	return rtp_data_transcoder(&endp->trans_net, endp, DEST_NETWORK, fd);
}

static int rtp_data_trans_bts(struct bsc_fd *fd, unsigned int what)
{
	struct mgcp_endpoint *endp;
	endp = (struct mgcp_endpoint *) fd->data;

	return rtp_data_transcoder(&endp->trans_bts, endp, DEST_BTS, fd);
}

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) {
		close(fd->fd);
		fd->fd = -1;
		return -1;
	}

	return 0;
}

static int set_ip_tos(int fd, int tos)
{
	int ret;
	ret = setsockopt(fd, IPPROTO_IP, IP_TOS,
			 &tos, sizeof(tos));
	return ret != 0;
}

static int bind_rtp(struct mgcp_config *cfg, struct mgcp_rtp_end *rtp_end, int endpno)
{
	if (create_bind(cfg->source_addr, &rtp_end->rtp, rtp_end->local_port) != 0) {
		LOGP(DMGCP, LOGL_ERROR, "Failed to create RTP port: %s:%d on 0x%x\n",
		       cfg->source_addr, rtp_end->local_port, endpno);
		goto cleanup0;
	}

	if (create_bind(cfg->source_addr, &rtp_end->rtcp, rtp_end->local_port + 1) != 0) {
		LOGP(DMGCP, LOGL_ERROR, "Failed to create RTCP port: %s:%d on 0x%x\n",
		       cfg->source_addr, rtp_end->local_port + 1, endpno);
		goto cleanup1;
	}

	set_ip_tos(rtp_end->rtp.fd, cfg->endp_dscp);
	set_ip_tos(rtp_end->rtcp.fd, cfg->endp_dscp);

	rtp_end->rtp.when = BSC_FD_READ;
	if (bsc_register_fd(&rtp_end->rtp) != 0) {
		LOGP(DMGCP, LOGL_ERROR, "Failed to register RTP port %d on 0x%x\n",
			rtp_end->local_port, endpno);
		goto cleanup2;
	}

	rtp_end->rtcp.when = BSC_FD_READ;
	if (bsc_register_fd(&rtp_end->rtcp) != 0) {
		LOGP(DMGCP, LOGL_ERROR, "Failed to register RTCP port %d on 0x%x\n",
			rtp_end->local_port + 1, endpno);
		goto cleanup3;
	}

	return 0;

cleanup3:
	bsc_unregister_fd(&rtp_end->rtp);
cleanup2:
	close(rtp_end->rtcp.fd);
	rtp_end->rtcp.fd = -1;
cleanup1:
	close(rtp_end->rtp.fd);
	rtp_end->rtp.fd = -1;
cleanup0:
	return -1;
}

static int int_bind(const char *port,
		    struct mgcp_rtp_end *end, int (*cb)(struct bsc_fd *, unsigned),
		    struct mgcp_endpoint *_endp, int rtp_port)
{
	if (end->rtp.fd != -1 || end->rtcp.fd != -1) {
		LOGP(DMGCP, LOGL_ERROR, "Previous %s was still bound on %d\n",
			port, ENDPOINT_NUMBER(_endp));
		mgcp_free_rtp_port(end);
	}

	end->local_port = rtp_port;
	end->rtp.cb = cb;
	end->rtp.data = _endp;
	end->rtcp.data = _endp;
	end->rtcp.cb = cb;
	return bind_rtp(_endp->cfg, end, ENDPOINT_NUMBER(_endp));
}


int mgcp_bind_bts_rtp_port(struct mgcp_endpoint *endp, int rtp_port)
{
	return int_bind("bts-port", &endp->bts_end,
			rtp_data_bts, endp, rtp_port);
}

int mgcp_bind_net_rtp_port(struct mgcp_endpoint *endp, int rtp_port)
{
	return int_bind("net-port", &endp->net_end,
			rtp_data_net, endp, rtp_port);
}

int mgcp_bind_trans_net_rtp_port(struct mgcp_endpoint *endp, int rtp_port)
{
	return int_bind("trans-net", &endp->trans_net,
			rtp_data_trans_net, endp, rtp_port);
}

int mgcp_bind_trans_bts_rtp_port(struct mgcp_endpoint *endp, int rtp_port)
{
	return int_bind("trans-bts", &endp->trans_bts,
			rtp_data_trans_bts, endp, rtp_port);
}

int mgcp_free_rtp_port(struct mgcp_rtp_end *end)
{
	if (end->rtp.fd != -1) {
		close(end->rtp.fd);
		end->rtp.fd = -1;
		bsc_unregister_fd(&end->rtp);
	}

	if (end->rtcp.fd != -1) {
		close(end->rtcp.fd);
		end->rtcp.fd = -1;
		bsc_unregister_fd(&end->rtcp);
	}

	return 0;
}