aboutsummaryrefslogtreecommitdiffstats
path: root/src/libmgcp/mgcp_network.c
blob: abce6e49de08955752378bc7368e4baf7dd2893b (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
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
/* A Media Gateway Control Protocol Media Gateway: RFC 3435 */
/* The protocol implementation */

/*
 * (C) 2009-2012 by Holger Hans Peter Freyther <zecke@selfish.org>
 * (C) 2009-2012 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 <time.h>
#include <limits.h>

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

#include <osmocom/core/msgb.h>
#include <osmocom/core/select.h>

#include <osmocom/netif/rtp.h>

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

#include <openbsc/osmux.h>

#warning "Make use of the rtp proxy code"


#define RTP_SEQ_MOD		(1 << 16)
#define RTP_MAX_DROPOUT		3000
#define RTP_MAX_MISORDER	100
#define RTP_BUF_SIZE		4096

enum {
	MGCP_PROTO_RTP,
	MGCP_PROTO_RTCP,
};

/**
 * This does not need to be a precision timestamp and
 * is allowed to wrap quite fast. The returned value is
 * 1/unit seconds.
 */
static uint32_t get_current_ts(unsigned unit)
{
	struct timespec tp;
	uint64_t ret;

	if (!unit)
		return 0;

	memset(&tp, 0, sizeof(tp));
	if (clock_gettime(CLOCK_MONOTONIC, &tp) != 0)
		LOGP(DMGCP, LOGL_NOTICE,
			"Getting the clock failed.\n");

	/* convert it to 1/unit seconds */
	ret = tp.tv_sec;
	ret *= unit;
	ret += (int64_t)tp.tv_nsec * unit / 1000 / 1000 / 1000;

	return ret;
}

int mgcp_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[] = { MGCP_DUMMY_LOAD };
	int rc;
	int was_rtcp = 0;

	rc = mgcp_udp_send(endp->net_end.rtp.fd, &endp->net_end.addr,
			   endp->net_end.rtp_port, buf, 1);

	if (rc == -1)
		goto failed;

	if (endp->tcfg->omit_rtcp)
		return rc;

	was_rtcp = 1;
	rc = mgcp_udp_send(endp->net_end.rtcp.fd, &endp->net_end.addr,
			   endp->net_end.rtcp_port, buf, 1);

	if (rc >= 0)
		return rc;

failed:
	LOGP(DMGCP, LOGL_ERROR,
		"Failed to send dummy %s packet: %s on: 0x%x to %s:%d\n",
		was_rtcp ? "RTCP" : "RTP",
		strerror(errno), ENDPOINT_NUMBER(endp), inet_ntoa(endp->net_end.addr),
		was_rtcp ? endp->net_end.rtcp_port : endp->net_end.rtp_port);

	return -1;
}

static int32_t compute_timestamp_aligment_error(struct mgcp_rtp_stream_state *sstate,
						int ptime, uint32_t timestamp)
{
	int32_t timestamp_delta;

	if (ptime == 0)
		return 0;

	/* Align according to: T - Tlast = k * Tptime */
	timestamp_delta = timestamp - sstate->last_timestamp;

	return timestamp_delta % ptime;
}

static int check_rtp_timestamp(struct mgcp_endpoint *endp,
			       struct mgcp_rtp_state *state,
			       struct mgcp_rtp_stream_state *sstate,
			       struct mgcp_rtp_end *rtp_end,
			       struct sockaddr_in *addr,
			       uint16_t seq, uint32_t timestamp,
			       const char *text, int32_t *tsdelta_out)
{
	int32_t tsdelta;
	int32_t timestamp_error;

	/* Not fully intialized, skip */
	if (sstate->last_tsdelta == 0 && timestamp == sstate->last_timestamp)
		return 0;

	if (seq == sstate->last_seq) {
		if (timestamp != sstate->last_timestamp) {
			sstate->err_ts_counter += 1;
			LOGP(DMGCP, LOGL_ERROR,
			     "The %s timestamp delta is != 0 but the sequence "
			     "number %d is the same, "
			     "TS offset: %d, SeqNo offset: %d "
			     "on 0x%x SSRC: %u timestamp: %u "
			     "from %s:%d in %d\n",
			     text, seq,
			     state->timestamp_offset, state->seq_offset,
			     ENDPOINT_NUMBER(endp), sstate->ssrc, timestamp,
			     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
			     endp->conn_mode);
		}
		return 0;
	}

	tsdelta =
		(int32_t)(timestamp - sstate->last_timestamp) /
		(int16_t)(seq - sstate->last_seq);

	if (tsdelta == 0) {
		/* Don't update *tsdelta_out */
		LOGP(DMGCP, LOGL_NOTICE,
		     "The %s timestamp delta is %d "
		     "on 0x%x SSRC: %u timestamp: %u "
		     "from %s:%d in %d\n",
		     text, tsdelta,
		     ENDPOINT_NUMBER(endp), sstate->ssrc, timestamp,
		     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
		     endp->conn_mode);

		return 0;
	}

	if (sstate->last_tsdelta != tsdelta) {
		if (sstate->last_tsdelta) {
			LOGP(DMGCP, LOGL_INFO,
			     "The %s timestamp delta changes from %d to %d "
			     "on 0x%x SSRC: %u timestamp: %u from %s:%d in %d\n",
			     text, sstate->last_tsdelta, tsdelta,
			     ENDPOINT_NUMBER(endp), sstate->ssrc, timestamp,
			     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
			     endp->conn_mode);
		}
	}

	if (tsdelta_out)
		*tsdelta_out = tsdelta;

	timestamp_error =
		compute_timestamp_aligment_error(sstate, state->packet_duration,
						 timestamp);

	if (timestamp_error) {
		sstate->err_ts_counter += 1;
		LOGP(DMGCP, LOGL_NOTICE,
		     "The %s timestamp has an alignment error of %d "
		     "on 0x%x SSRC: %u "
		     "SeqNo delta: %d, TS delta: %d, dTS/dSeq: %d "
		     "from %s:%d in mode %d. ptime: %d\n",
		     text, timestamp_error,
		     ENDPOINT_NUMBER(endp), sstate->ssrc,
		     (int16_t)(seq - sstate->last_seq),
		     (int32_t)(timestamp - sstate->last_timestamp),
		     tsdelta,
		     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
		     endp->conn_mode, state->packet_duration);
	}
	return 1;
}

/* Set the timestamp offset according to the packet duration. */
static int adjust_rtp_timestamp_offset(struct mgcp_endpoint *endp,
				       struct mgcp_rtp_state *state,
				       struct mgcp_rtp_end *rtp_end,
				       struct sockaddr_in *addr,
				       int16_t delta_seq, uint32_t in_timestamp)
{
	int32_t tsdelta = state->packet_duration;
	int timestamp_offset;
	uint32_t out_timestamp;

	if (tsdelta == 0) {
		tsdelta = state->out_stream.last_tsdelta;
		if (tsdelta != 0) {
			LOGP(DMGCP, LOGL_NOTICE,
			     "A fixed packet duration is not available on 0x%x, "
			     "using last output timestamp delta instead: %d "
			     "from %s:%d in %d\n",
			     ENDPOINT_NUMBER(endp), tsdelta,
			     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
			     endp->conn_mode);
		} else {
			tsdelta = rtp_end->codec.rate * 20 / 1000;
			LOGP(DMGCP, LOGL_NOTICE,
			     "Fixed packet duration and last timestamp delta "
			     "are not available on 0x%x, "
			     "using fixed 20ms instead: %d "
			     "from %s:%d in %d\n",
			     ENDPOINT_NUMBER(endp), tsdelta,
			     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
			     endp->conn_mode);
		}
	}

	out_timestamp = state->out_stream.last_timestamp + delta_seq * tsdelta;
	timestamp_offset = out_timestamp - in_timestamp;

	if (state->timestamp_offset != timestamp_offset) {
		state->timestamp_offset = timestamp_offset;

		LOGP(DMGCP, LOGL_NOTICE,
		     "Timestamp offset change on 0x%x SSRC: %u "
		     "SeqNo delta: %d, TS offset: %d, "
		     "from %s:%d in %d\n",
		     ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
		     delta_seq, state->timestamp_offset,
		     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
		     endp->conn_mode);
	}

	return timestamp_offset;
}

/* Set the timestamp offset according to the packet duration. */
static int align_rtp_timestamp_offset(struct mgcp_endpoint *endp,
				      struct mgcp_rtp_state *state,
				      struct mgcp_rtp_end *rtp_end,
				      struct sockaddr_in *addr,
				      uint32_t timestamp)
{
	int timestamp_error = 0;
	int ptime = state->packet_duration;

	/* Align according to: T + Toffs - Tlast = k * Tptime */

	timestamp_error = compute_timestamp_aligment_error(
		&state->out_stream, ptime,
		timestamp + state->timestamp_offset);

	if (timestamp_error) {
		state->timestamp_offset += ptime - timestamp_error;

		LOGP(DMGCP, LOGL_NOTICE,
		     "Corrected timestamp alignment error of %d on 0x%x SSRC: %u "
		     "new TS offset: %d, "
		     "from %s:%d in %d\n",
		     timestamp_error,
		     ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
		     state->timestamp_offset, inet_ntoa(addr->sin_addr),
		     ntohs(addr->sin_port), endp->conn_mode);
	}

	OSMO_ASSERT(compute_timestamp_aligment_error(&state->out_stream, ptime,
						     timestamp + state->timestamp_offset) == 0);

	return timestamp_error;
}

int mgcp_rtp_processing_default(struct mgcp_endpoint *endp, struct mgcp_rtp_end *dst_end,
				char *data, int *len, int buf_size)
{
	return 0;
}

int mgcp_setup_rtp_processing_default(struct mgcp_endpoint *endp,
				      struct mgcp_rtp_end *dst_end,
				      struct mgcp_rtp_end *src_end)
{
	return 0;
}

void mgcp_get_net_downlink_format_default(struct mgcp_endpoint *endp,
					  int *payload_type,
					  const char**audio_name,
					  const char**fmtp_extra)
{
	/* Use the BTS side parameters when passing the SDP data (for
	 * downlink) to the net peer.
	 */
	*payload_type = endp->bts_end.codec.payload_type;
	*audio_name = endp->bts_end.codec.audio_name;
	*fmtp_extra = endp->bts_end.fmtp_extra;
}


void mgcp_rtp_annex_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *state,
			const uint16_t seq, const int32_t transit,
			const uint32_t ssrc)
{
	int32_t d;

	/* initialize or re-initialize */
	if (!state->stats_initialized || state->stats_ssrc != ssrc) {
		state->stats_initialized = 1;
		state->stats_base_seq = seq;
		state->stats_max_seq = seq - 1;
		state->stats_ssrc = ssrc;
		state->stats_jitter = 0;
		state->stats_transit = transit;
		state->stats_cycles = 0;
	} else {
		uint16_t udelta;

		/*
		 * The below takes the shape of the validation of
		 * Appendix A. Check if there is something weird with
		 * the sequence number, otherwise check for a wrap
		 * around in the sequence number.
		 * It can't wrap during the initialization so let's
		 * skip it here. The Appendix A probably doesn't have
		 * this issue because of the probation.
		 */
		udelta = seq - state->stats_max_seq;
		if (udelta < RTP_MAX_DROPOUT) {
			if (seq < state->stats_max_seq)
				state->stats_cycles += RTP_SEQ_MOD;
		} else if (udelta <= RTP_SEQ_MOD - RTP_MAX_MISORDER) {
			LOGP(DMGCP, LOGL_NOTICE,
				"RTP seqno made a very large jump on 0x%x delta: %u\n",
				ENDPOINT_NUMBER(endp), udelta);
		}
	}

	/*
	 * Calculate the jitter between the two packages. The TS should be
	 * taken closer to the read function. This was taken from the
	 * Appendix A of RFC 3550. Timestamp and arrival_time have a 1/rate
	 * resolution.
	 */
	d = transit - state->stats_transit;
	state->stats_transit = transit;
	if (d < 0)
		d = -d;
	state->stats_jitter += d - ((state->stats_jitter + 8) >> 4);
	state->stats_max_seq = seq;
}



/**
 * The RFC 3550 Appendix A assumes there are multiple sources but
 * some of the supported endpoints (e.g. the nanoBTS) can only handle
 * one source and this code will patch RTP header to appear as if there
 * is only one source.
 * There is also no probation period for new sources. Every RTP header
 * we receive will be seen as a switch in streams.
 */
void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *state,
			  struct mgcp_rtp_end *rtp_end, struct sockaddr_in *addr,
			  char *data, int len)
{
	uint32_t arrival_time;
	int32_t transit;
	uint16_t seq;
	uint32_t timestamp, ssrc;
	struct rtp_hdr *rtp_hdr;
	int payload = rtp_end->codec.payload_type;

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

	rtp_hdr = (struct rtp_hdr *) data;
	seq = ntohs(rtp_hdr->sequence);
	timestamp = ntohl(rtp_hdr->timestamp);
	arrival_time = get_current_ts(rtp_end->codec.rate);
	ssrc = ntohl(rtp_hdr->ssrc);
	transit = arrival_time - timestamp;

	mgcp_rtp_annex_count(endp, state, seq, transit, ssrc);

	if (!state->initialized) {
		state->initialized = 1;
		state->in_stream.last_seq = seq - 1;
		state->in_stream.ssrc = state->orig_ssrc = ssrc;
		state->in_stream.last_tsdelta = 0;
		state->packet_duration = mgcp_rtp_packet_duration(endp, rtp_end);
		state->out_stream = state->in_stream;
		state->out_stream.last_timestamp = timestamp;
		state->out_stream.ssrc = ssrc - 1; /* force output SSRC change */
		LOGP(DMGCP, LOGL_INFO,
			"Initializing stream on 0x%x SSRC: %u timestamp: %u "
			"pkt-duration: %d, from %s:%d in %d\n",
			ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
			state->seq_offset, state->packet_duration,
			inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
			endp->conn_mode);
		if (state->packet_duration == 0) {
			state->packet_duration = rtp_end->codec.rate * 20 / 1000;
			LOGP(DMGCP, LOGL_NOTICE,
			     "Fixed packet duration is not available on 0x%x, "
			     "using fixed 20ms instead: %d from %s:%d in %d\n",
			     ENDPOINT_NUMBER(endp), state->packet_duration,
			     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
			     endp->conn_mode);
		}
	} else if (state->in_stream.ssrc != ssrc) {
		LOGP(DMGCP, LOGL_NOTICE,
			"The SSRC changed on 0x%x: %u -> %u  "
			"from %s:%d in %d\n",
			ENDPOINT_NUMBER(endp),
			state->in_stream.ssrc, rtp_hdr->ssrc,
			inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
			endp->conn_mode);

		state->in_stream.ssrc = ssrc;
		if (rtp_end->force_constant_ssrc) {
			int16_t delta_seq;

			/* Always increment seqno by 1 */
			state->seq_offset =
				(state->out_stream.last_seq + 1) - seq;

			/* Estimate number of packets that would have been sent */
			delta_seq =
				(arrival_time - state->in_stream.last_arrival_time
				 + state->packet_duration/2) /
				state->packet_duration;

			adjust_rtp_timestamp_offset(endp, state, rtp_end, addr,
						    delta_seq, timestamp);

			state->patch_ssrc = 1;
			ssrc = state->orig_ssrc;
			if (rtp_end->force_constant_ssrc != -1)
				rtp_end->force_constant_ssrc -= 1;

			LOGP(DMGCP, LOGL_NOTICE,
			     "SSRC patching enabled on 0x%x SSRC: %u "
			     "SeqNo offset: %d, TS offset: %d "
			     "from %s:%d in %d\n",
			     ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
			     state->seq_offset, state->timestamp_offset,
			     inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
			     endp->conn_mode);
		}

		state->in_stream.last_tsdelta = 0;
	} else {
		/* Compute current per-packet timestamp delta */
		check_rtp_timestamp(endp, state, &state->in_stream, rtp_end, addr,
				    seq, timestamp, "input",
				    &state->in_stream.last_tsdelta);

		if (state->patch_ssrc)
			ssrc = state->orig_ssrc;
	}

	/* Save before patching */
	state->in_stream.last_timestamp = timestamp;
	state->in_stream.last_seq = seq;
	state->in_stream.last_arrival_time = arrival_time;

	if (rtp_end->force_aligned_timing &&
	    state->out_stream.ssrc == ssrc && state->packet_duration)
		/* Align the timestamp offset */
		align_rtp_timestamp_offset(endp, state, rtp_end, addr, timestamp);

	/* Store the updated SSRC back to the packet */
	if (state->patch_ssrc)
		rtp_hdr->ssrc = htonl(ssrc);

	/* Apply the offset and store it back to the packet.
	 * This won't change anything if the offset is 0, so the conditional is
	 * omitted. */
	seq += state->seq_offset;
	rtp_hdr->sequence = htons(seq);
	timestamp += state->timestamp_offset;
	rtp_hdr->timestamp = htonl(timestamp);

	/* Check again, whether the timestamps are still valid */
	if (state->out_stream.ssrc == ssrc)
		check_rtp_timestamp(endp, state, &state->out_stream, rtp_end,
				    addr, seq, timestamp, "output",
				    &state->out_stream.last_tsdelta);

	/* Save output values */
	state->out_stream.last_seq = seq;
	state->out_stream.last_timestamp = timestamp;
	state->out_stream.ssrc = ssrc;

	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 mgcp_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;
}

int mgcp_send(struct mgcp_endpoint *endp, int dest, int is_rtp,
	      struct sockaddr_in *addr, char *buf, int rc)
{
	struct mgcp_trunk_config *tcfg = endp->tcfg;
	struct mgcp_rtp_end *rtp_end;
	struct mgcp_rtp_state *rtp_state;
	int tap_idx;

	/* 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 == MGCP_DEST_NET) {
		rtp_end = &endp->net_end;
		rtp_state = &endp->bts_state;
		tap_idx = MGCP_TAP_NET_OUT;
	} else {
		rtp_end = &endp->bts_end;
		rtp_state = &endp->net_state;
		tap_idx = MGCP_TAP_BTS_OUT;
	}

	if (!rtp_end->output_enabled)
		rtp_end->dropped_packets += 1;
	else if (is_rtp) {
		int cont;
		int nbytes = 0;
		int len = rc;
		do {
			cont = endp->cfg->rtp_processing_cb(endp, rtp_end,
							buf, &len, RTP_BUF_SIZE);
			if (cont < 0)
				break;

			mgcp_patch_and_count(endp, rtp_state, rtp_end, addr, buf, len);
			forward_data(rtp_end->rtp.fd, &endp->taps[tap_idx],
				     buf, len);
			rc = mgcp_udp_send(rtp_end->rtp.fd,
					   &rtp_end->addr,
					   rtp_end->rtp_port, buf, len);

			if (rc <= 0)
				return rc;
			nbytes += rc;
			len = cont;
		} while (len > 0);
		return nbytes;
	} else if (!tcfg->omit_rtcp) {
		return mgcp_udp_send(rtp_end->rtcp.fd,
				     &rtp_end->addr,
				     rtp_end->rtcp_port, buf, rc);
	}

	return 0;
}

static int receive_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 osmo_fd *fd, unsigned int what)
{
	char buf[RTP_BUF_SIZE];
	struct sockaddr_in addr;
	struct mgcp_endpoint *endp;
	int rc, proto;

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

	rc = receive_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,
			"Endpoint 0x%x data from wrong address %s vs. ",
			ENDPOINT_NUMBER(endp), inet_ntoa(addr.sin_addr));
		LOGPC(DMGCP, LOGL_ERROR,
			"%s\n", inet_ntoa(endp->net_end.addr));
		return -1;
	}

	switch(endp->type) {
	case MGCP_RTP_DEFAULT:
	case MGCP_RTP_TRANSCODED:
		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;
		}
		break;
	case MGCP_OSMUX_BSC:
	case MGCP_OSMUX_BSC_NAT:
		break;
	}

	/* throw away the dummy message */
	if (rc == 1 && buf[0] == MGCP_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 ? MGCP_PROTO_RTP : MGCP_PROTO_RTCP;
	endp->net_end.packets += 1;
	endp->net_end.octets += rc;

	forward_data(fd->fd, &endp->taps[MGCP_TAP_NET_IN], buf, rc);

	switch (endp->type) {
	case MGCP_RTP_DEFAULT:
		return mgcp_send(endp, MGCP_DEST_BTS, proto == MGCP_PROTO_RTP,
				 &addr, buf, rc);
	case MGCP_RTP_TRANSCODED:
		return mgcp_send_transcoder(&endp->trans_net, endp->cfg,
					    proto == MGCP_PROTO_RTP, buf, rc);
	case MGCP_OSMUX_BSC_NAT:
		return osmux_xfrm_to_osmux(MGCP_DEST_BTS, buf, rc, endp);
	case MGCP_OSMUX_BSC:	/* Should not happen */
		break;
	}

	LOGP(DMGCP, LOGL_ERROR, "Bad MGCP type %u on endpoint %u\n",
	     endp->type, ENDPOINT_NUMBER(endp));
	return 0;
}

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

	if (proto == MGCP_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 == MGCP_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 osmo_fd *fd, unsigned int what)
{
	char buf[RTP_BUF_SIZE];
	struct sockaddr_in addr;
	struct mgcp_endpoint *endp;
	int rc, proto;

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

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

	proto = fd == &endp->bts_end.rtp ? MGCP_PROTO_RTP : MGCP_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] == MGCP_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;
	endp->bts_end.octets += rc;

	forward_data(fd->fd, &endp->taps[MGCP_TAP_BTS_IN], buf, rc);

	switch (endp->type) {
	case MGCP_RTP_DEFAULT:
		return mgcp_send(endp, MGCP_DEST_NET, proto == MGCP_PROTO_RTP,
				 &addr, buf, rc);
	case MGCP_RTP_TRANSCODED:
		return mgcp_send_transcoder(&endp->trans_bts, endp->cfg,
					    proto == MGCP_PROTO_RTP, buf, rc);
	case MGCP_OSMUX_BSC:
		/* OSMUX translation: BTS -> BSC */
		return osmux_xfrm_to_osmux(MGCP_DEST_NET, buf, rc, endp);
	case MGCP_OSMUX_BSC_NAT:
		break;	/* Should not happen */
	}

	LOGP(DMGCP, LOGL_ERROR, "Bad MGCP type %u on endpoint %u\n",
	     endp->type, ENDPOINT_NUMBER(endp));
	return 0;
}

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

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

	proto = fd == &end->rtp ? MGCP_PROTO_RTP : MGCP_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] == MGCP_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 mgcp_send(_endp, dest, proto == MGCP_PROTO_RTP, &addr, buf, rc);
}

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

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

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

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

int mgcp_create_bind(const char *source_addr, struct osmo_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;
}

int mgcp_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, const char *source_addr,
			struct mgcp_rtp_end *rtp_end, int endpno)
{
	if (mgcp_create_bind(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",
		       source_addr, rtp_end->local_port, endpno);
		goto cleanup0;
	}

	if (mgcp_create_bind(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",
		       source_addr, rtp_end->local_port + 1, endpno);
		goto cleanup1;
	}

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

	rtp_end->rtp.when = BSC_FD_READ;
	if (osmo_fd_register(&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 (osmo_fd_register(&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:
	osmo_fd_unregister(&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 osmo_fd *, unsigned),
		    struct mgcp_endpoint *_endp,
		    const char *source_addr, 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, source_addr, 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,
			mgcp_bts_src_addr(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,
			mgcp_net_src_addr(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,
			endp->cfg->source_addr, 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,
			endp->cfg->source_addr, 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;
		osmo_fd_unregister(&end->rtp);
	}

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

	return 0;
}


void mgcp_state_calc_loss(struct mgcp_rtp_state *state,
			struct mgcp_rtp_end *end, uint32_t *expected,
			int *loss)
{
	*expected = state->stats_cycles + state->stats_max_seq;
	*expected = *expected - state->stats_base_seq + 1;

	if (!state->stats_initialized) {
		*expected = 0;
		*loss = 0;
		return;
	}

	/*
	 * Make sure the sign is correct and use the biggest
	 * positive/negative number that fits.
	 */
	*loss = *expected - end->packets;
	if (*expected < end->packets) {
		if (*loss > 0)
			*loss = INT_MIN;
	} else {
		if (*loss < 0)
			*loss = INT_MAX;
	}
}

uint32_t mgcp_state_calc_jitter(struct mgcp_rtp_state *state)
{
	if (!state->stats_initialized)
		return 0;
	return state->stats_jitter >> 4;
}