aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/udp.c
blob: 531e25466b5394dd318a3a8cd2ae8dbcee5f281d (plain) (blame)
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
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
/*
 * UDP prototype streaming system
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * UDP protocol
 */

#define _DEFAULT_SOURCE
#define _BSD_SOURCE     /* Needed for using struct ip_mreq with recent glibc */

#include "avformat.h"
#include "avio_internal.h"
#include "libavutil/avassert.h"
#include "libavutil/parseutils.h"
#include "libavutil/fifo.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/avstring.h"
#include "libavutil/opt.h"
#include "libavutil/log.h"
#include "libavutil/time.h"
#include "internal.h"
#include "network.h"
#include "os_support.h"
#include "url.h"

#if HAVE_UDPLITE_H
#include "udplite.h"
#else
/* On many Linux systems, udplite.h is missing but the kernel supports UDP-Lite.
 * So, we provide a fallback here.
 */
#define UDPLITE_SEND_CSCOV                               10
#define UDPLITE_RECV_CSCOV                               11
#endif

#ifndef IPPROTO_UDPLITE
#define IPPROTO_UDPLITE                                  136
#endif

#if HAVE_PTHREAD_CANCEL
#include <pthread.h>
#endif

#ifndef HAVE_PTHREAD_CANCEL
#define HAVE_PTHREAD_CANCEL 0
#endif

#ifndef IPV6_ADD_MEMBERSHIP
#define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
#define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
#endif

#define UDP_TX_BUF_SIZE 32768
#define UDP_MAX_PKT_SIZE 65536
#define UDP_HEADER_SIZE 8

typedef struct UDPContext {
    const AVClass *class;
    int udp_fd;
    int ttl;
    int udplite_coverage;
    int buffer_size;
    int pkt_size;
    int is_multicast;
    int is_broadcast;
    int local_port;
    int reuse_socket;
    int overrun_nonfatal;
    struct sockaddr_storage dest_addr;
    int dest_addr_len;
    int is_connected;

    /* Circular Buffer variables for use in UDP receive code */
    int circular_buffer_size;
    AVFifoBuffer *fifo;
    int circular_buffer_error;
    int64_t packet_gap; /* delay between transmitted packets */
    int close_req;
#if HAVE_PTHREAD_CANCEL
    pthread_t circular_buffer_thread;
    pthread_mutex_t mutex;
    pthread_cond_t cond;
    int thread_started;
#endif
    uint8_t tmp[UDP_MAX_PKT_SIZE+4];
    int remaining_in_dg;
    char *localaddr;
    int timeout;
    struct sockaddr_storage local_addr_storage;
    char *sources;
    char *block;
} UDPContext;

#define OFFSET(x) offsetof(UDPContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
    { "buffer_size",    "System data size (in bytes)",                     OFFSET(buffer_size),    AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },
    { "packet_gap",     "Delay between packets",                           OFFSET(packet_gap),     AV_OPT_TYPE_DURATION,    { .i64 = 0  },     0, INT_MAX, .flags = E },
    { "localport",      "Local port",                                      OFFSET(local_port),     AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, D|E },
    { "local_port",     "Local port",                                      OFFSET(local_port),     AV_OPT_TYPE_INT,    { .i64 = -1 },    -1, INT_MAX, .flags = D|E },
    { "localaddr",      "Local address",                                   OFFSET(localaddr),      AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },
    { "udplite_coverage", "choose UDPLite head size which should be validated by checksum", OFFSET(udplite_coverage), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, D|E },
    { "pkt_size",       "Maximum UDP packet size",                         OFFSET(pkt_size),       AV_OPT_TYPE_INT,    { .i64 = 1472 },  -1, INT_MAX, .flags = D|E },
    { "reuse",          "explicitly allow reusing UDP sockets",            OFFSET(reuse_socket),   AV_OPT_TYPE_BOOL,   { .i64 = -1 },    -1, 1,       D|E },
    { "reuse_socket",   "explicitly allow reusing UDP sockets",            OFFSET(reuse_socket),   AV_OPT_TYPE_BOOL,   { .i64 = -1 },    -1, 1,       .flags = D|E },
    { "broadcast", "explicitly allow or disallow broadcast destination",   OFFSET(is_broadcast),   AV_OPT_TYPE_BOOL,   { .i64 = 0  },     0, 1,       E },
    { "ttl",            "Time to live (multicast only)",                   OFFSET(ttl),            AV_OPT_TYPE_INT,    { .i64 = 16 },     0, INT_MAX, E },
    { "connect",        "set if connect() should be called on socket",     OFFSET(is_connected),   AV_OPT_TYPE_BOOL,   { .i64 =  0 },     0, 1,       .flags = D|E },
    { "fifo_size",      "set the UDP receiving circular buffer size, expressed as a number of packets with size of 188 bytes", OFFSET(circular_buffer_size), AV_OPT_TYPE_INT, {.i64 = 7*4096}, 0, INT_MAX, D },
    { "overrun_nonfatal", "survive in case of UDP receiving circular buffer overrun", OFFSET(overrun_nonfatal), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1,    D },
    { "timeout",        "set raise error timeout (only in read mode)",     OFFSET(timeout),        AV_OPT_TYPE_INT,    { .i64 = 0 },      0, INT_MAX, D },
    { "sources",        "Source list",                                     OFFSET(sources),        AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },
    { "block",          "Block list",                                      OFFSET(block),          AV_OPT_TYPE_STRING, { .str = NULL },               .flags = D|E },
    { NULL }
};

static const AVClass udp_class = {
    .class_name = "udp",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

static const AVClass udplite_context_class = {
    .class_name     = "udplite",
    .item_name      = av_default_item_name,
    .option         = options,
    .version        = LIBAVUTIL_VERSION_INT,
};

static void log_net_error(void *ctx, int level, const char* prefix)
{
    char errbuf[100];
    av_strerror(ff_neterrno(), errbuf, sizeof(errbuf));
    av_log(ctx, level, "%s: %s\n", prefix, errbuf);
}

static int udp_set_multicast_ttl(int sockfd, int mcastTTL,
                                 struct sockaddr *addr)
{
#ifdef IP_MULTICAST_TTL
    if (addr->sa_family == AF_INET) {
        if (setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, &mcastTTL, sizeof(mcastTTL)) < 0) {
            log_net_error(NULL, AV_LOG_ERROR, "setsockopt(IP_MULTICAST_TTL)");
            return -1;
        }
    }
#endif
#if defined(IPPROTO_IPV6) && defined(IPV6_MULTICAST_HOPS)
    if (addr->sa_family == AF_INET6) {
        if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &mcastTTL, sizeof(mcastTTL)) < 0) {
            log_net_error(NULL, AV_LOG_ERROR, "setsockopt(IPV6_MULTICAST_HOPS)");
            return -1;
        }
    }
#endif
    return 0;
}

static int udp_join_multicast_group(int sockfd, struct sockaddr *addr,struct sockaddr *local_addr)
{
#ifdef IP_ADD_MEMBERSHIP
    if (addr->sa_family == AF_INET) {
        struct ip_mreq mreq;

        mreq.imr_multiaddr.s_addr = ((struct sockaddr_in *)addr)->sin_addr.s_addr;
        if (local_addr)
            mreq.imr_interface= ((struct sockaddr_in *)local_addr)->sin_addr;
        else
            mreq.imr_interface.s_addr= INADDR_ANY;
        if (setsockopt(sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (const void *)&mreq, sizeof(mreq)) < 0) {
            log_net_error(NULL, AV_LOG_ERROR, "setsockopt(IP_ADD_MEMBERSHIP)");
            return -1;
        }
    }
#endif
#if HAVE_STRUCT_IPV6_MREQ && defined(IPPROTO_IPV6)
    if (addr->sa_family == AF_INET6) {
        struct ipv6_mreq mreq6;

        memcpy(&mreq6.ipv6mr_multiaddr, &(((struct sockaddr_in6 *)addr)->sin6_addr), sizeof(struct in6_addr));
        mreq6.ipv6mr_interface= 0;
        if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6)) < 0) {
            log_net_error(NULL, AV_LOG_ERROR, "setsockopt(IPV6_ADD_MEMBERSHIP)");
            return -1;
        }
    }
#endif
    return 0;
}

static int udp_leave_multicast_group(int sockfd, struct sockaddr *addr,struct sockaddr *local_addr)
{
#ifdef IP_DROP_MEMBERSHIP
    if (addr->sa_family == AF_INET) {
        struct ip_mreq mreq;

        mreq.imr_multiaddr.s_addr = ((struct sockaddr_in *)addr)->sin_addr.s_addr;
        if (local_addr)
            mreq.imr_interface= ((struct sockaddr_in *)local_addr)->sin_addr;
        else
            mreq.imr_interface.s_addr= INADDR_ANY;
        if (setsockopt(sockfd, IPPROTO_IP, IP_DROP_MEMBERSHIP, (const void *)&mreq, sizeof(mreq)) < 0) {
            log_net_error(NULL, AV_LOG_ERROR, "setsockopt(IP_DROP_MEMBERSHIP)");
            return -1;
        }
    }
#endif
#if HAVE_STRUCT_IPV6_MREQ && defined(IPPROTO_IPV6)
    if (addr->sa_family == AF_INET6) {
        struct ipv6_mreq mreq6;

        memcpy(&mreq6.ipv6mr_multiaddr, &(((struct sockaddr_in6 *)addr)->sin6_addr), sizeof(struct in6_addr));
        mreq6.ipv6mr_interface= 0;
        if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6)) < 0) {
            log_net_error(NULL, AV_LOG_ERROR, "setsockopt(IPV6_DROP_MEMBERSHIP)");
            return -1;
        }
    }
#endif
    return 0;
}

static struct addrinfo *udp_resolve_host(URLContext *h,
                                         const char *hostname, int port,
                                         int type, int family, int flags)
{
    struct addrinfo hints = { 0 }, *res = 0;
    int error;
    char sport[16];
    const char *node = 0, *service = "0";

    if (port > 0) {
        snprintf(sport, sizeof(sport), "%d", port);
        service = sport;
    }
    if ((hostname) && (hostname[0] != '\0') && (hostname[0] != '?')) {
        node = hostname;
    }
    hints.ai_socktype = type;
    hints.ai_family   = family;
    hints.ai_flags = flags;
    if ((error = getaddrinfo(node, service, &hints, &res))) {
        res = NULL;
        av_log(h, AV_LOG_ERROR, "getaddrinfo(%s, %s): %s\n",
               node ? node : "unknown",
               service,
               gai_strerror(error));
    }

    return res;
}

static int udp_set_multicast_sources(URLContext *h,
                                     int sockfd, struct sockaddr *addr,
                                     int addr_len, char **sources,
                                     int nb_sources, int include)
{
#if HAVE_STRUCT_GROUP_SOURCE_REQ && defined(MCAST_BLOCK_SOURCE) && !defined(_WIN32)
    /* These ones are available in the microsoft SDK, but don't seem to work
     * as on linux, so just prefer the v4-only approach there for now. */
    int i;
    for (i = 0; i < nb_sources; i++) {
        struct group_source_req mreqs;
        int level = addr->sa_family == AF_INET ? IPPROTO_IP : IPPROTO_IPV6;
        struct addrinfo *sourceaddr = udp_resolve_host(h, sources[i], 0,
                                                       SOCK_DGRAM, AF_UNSPEC,
                                                       0);
        if (!sourceaddr)
            return AVERROR(ENOENT);

        mreqs.gsr_interface = 0;
        memcpy(&mreqs.gsr_group, addr, addr_len);
        memcpy(&mreqs.gsr_source, sourceaddr->ai_addr, sourceaddr->ai_addrlen);
        freeaddrinfo(sourceaddr);

        if (setsockopt(sockfd, level,
                       include ? MCAST_JOIN_SOURCE_GROUP : MCAST_BLOCK_SOURCE,
                       (const void *)&mreqs, sizeof(mreqs)) < 0) {
            if (include)
                log_net_error(NULL, AV_LOG_ERROR, "setsockopt(MCAST_JOIN_SOURCE_GROUP)");
            else
                log_net_error(NULL, AV_LOG_ERROR, "setsockopt(MCAST_BLOCK_SOURCE)");
            return ff_neterrno();
        }
    }
#elif HAVE_STRUCT_IP_MREQ_SOURCE && defined(IP_BLOCK_SOURCE)
    int i;
    if (addr->sa_family != AF_INET) {
        av_log(NULL, AV_LOG_ERROR,
               "Setting multicast sources only supported for IPv4\n");
        return AVERROR(EINVAL);
    }
    for (i = 0; i < nb_sources; i++) {
        struct ip_mreq_source mreqs;
        struct addrinfo *sourceaddr = udp_resolve_host(h, sources[i], 0,
                                                       SOCK_DGRAM, AF_UNSPEC,
                                                       0);
        if (!sourceaddr)
            return AVERROR(ENOENT);
        if (sourceaddr->ai_addr->sa_family != AF_INET) {
            freeaddrinfo(sourceaddr);
            av_log(NULL, AV_LOG_ERROR, "%s is of incorrect protocol family\n",
                   sources[i]);
            return AVERROR(EINVAL);
        }

        mreqs.imr_multiaddr.s_addr = ((struct sockaddr_in *)addr)->sin_addr.s_addr;
        mreqs.imr_interface.s_addr = INADDR_ANY;
        mreqs.imr_sourceaddr.s_addr = ((struct sockaddr_in *)sourceaddr->ai_addr)->sin_addr.s_addr;
        freeaddrinfo(sourceaddr);

        if (setsockopt(sockfd, IPPROTO_IP,
                       include ? IP_ADD_SOURCE_MEMBERSHIP : IP_BLOCK_SOURCE,
                       (const void *)&mreqs, sizeof(mreqs)) < 0) {
            if (include)
                log_net_error(NULL, AV_LOG_ERROR, "setsockopt(IP_ADD_SOURCE_MEMBERSHIP)");
            else
                log_net_error(NULL, AV_LOG_ERROR, "setsockopt(IP_BLOCK_SOURCE)");
            return ff_neterrno();
        }
    }
#else
    return AVERROR(ENOSYS);
#endif
    return 0;
}
static int udp_set_url(URLContext *h,
                       struct sockaddr_storage *addr,
                       const char *hostname, int port)
{
    struct addrinfo *res0;
    int addr_len;

    res0 = udp_resolve_host(h, hostname, port, SOCK_DGRAM, AF_UNSPEC, 0);
    if (!res0) return AVERROR(EIO);
    memcpy(addr, res0->ai_addr, res0->ai_addrlen);
    addr_len = res0->ai_addrlen;
    freeaddrinfo(res0);

    return addr_len;
}

static int udp_socket_create(URLContext *h, struct sockaddr_storage *addr,
                             socklen_t *addr_len, const char *localaddr)
{
    UDPContext *s = h->priv_data;
    int udp_fd = -1;
    struct addrinfo *res0, *res;
    int family = AF_UNSPEC;

    if (((struct sockaddr *) &s->dest_addr)->sa_family)
        family = ((struct sockaddr *) &s->dest_addr)->sa_family;
    res0 = udp_resolve_host(h, (localaddr && localaddr[0]) ? localaddr : NULL,
                            s->local_port,
                            SOCK_DGRAM, family, AI_PASSIVE);
    if (!res0)
        goto fail;
    for (res = res0; res; res=res->ai_next) {
        if (s->udplite_coverage)
            udp_fd = ff_socket(res->ai_family, SOCK_DGRAM, IPPROTO_UDPLITE);
        else
            udp_fd = ff_socket(res->ai_family, SOCK_DGRAM, 0);
        if (udp_fd != -1) break;
        log_net_error(NULL, AV_LOG_ERROR, "socket");
    }

    if (udp_fd < 0)
        goto fail;

    memcpy(addr, res->ai_addr, res->ai_addrlen);
    *addr_len = res->ai_addrlen;

    freeaddrinfo(res0);

    return udp_fd;

 fail:
    if (udp_fd >= 0)
        closesocket(udp_fd);
    if(res0)
        freeaddrinfo(res0);
    return -1;
}

static int udp_port(struct sockaddr_storage *addr, int addr_len)
{
    char sbuf[sizeof(int)*3+1];
    int error;

    if ((error = getnameinfo((struct sockaddr *)addr, addr_len, NULL, 0,  sbuf, sizeof(sbuf), NI_NUMERICSERV)) != 0) {
        av_log(NULL, AV_LOG_ERROR, "getnameinfo: %s\n", gai_strerror(error));
        return -1;
    }

    return strtol(sbuf, NULL, 10);
}


/**
 * If no filename is given to av_open_input_file because you want to
 * get the local port first, then you must call this function to set
 * the remote server address.
 *
 * url syntax: udp://host:port[?option=val...]
 * option: 'ttl=n'       : set the ttl value (for multicast only)
 *         'localport=n' : set the local port
 *         'pkt_size=n'  : set max packet size
 *         'reuse=1'     : enable reusing the socket
 *         'overrun_nonfatal=1': survive in case of circular buffer overrun
 *
 * @param h media file context
 * @param uri of the remote server
 * @return zero if no error.
 */
int ff_udp_set_remote_url(URLContext *h, const char *uri)
{
    UDPContext *s = h->priv_data;
    char hostname[256], buf[10];
    int port;
    const char *p;

    av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port, NULL, 0, uri);

    /* set the destination address */
    s->dest_addr_len = udp_set_url(h, &s->dest_addr, hostname, port);
    if (s->dest_addr_len < 0) {
        return AVERROR(EIO);
    }
    s->is_multicast = ff_is_multicast_address((struct sockaddr*) &s->dest_addr);
    p = strchr(uri, '?');
    if (p) {
        if (av_find_info_tag(buf, sizeof(buf), "connect", p)) {
            int was_connected = s->is_connected;
            s->is_connected = strtol(buf, NULL, 10);
            if (s->is_connected && !was_connected) {
                if (connect(s->udp_fd, (struct sockaddr *) &s->dest_addr,
                            s->dest_addr_len)) {
                    s->is_connected = 0;
                    log_net_error(h, AV_LOG_ERROR, "connect");
                    return AVERROR(EIO);
                }
            }
        }
    }

    return 0;
}

/**
 * Return the local port used by the UDP connection
 * @param h media file context
 * @return the local port number
 */
int ff_udp_get_local_port(URLContext *h)
{
    UDPContext *s = h->priv_data;
    return s->local_port;
}

/**
 * Return the udp file handle for select() usage to wait for several RTP
 * streams at the same time.
 * @param h media file context
 */
static int udp_get_file_handle(URLContext *h)
{
    UDPContext *s = h->priv_data;
    return s->udp_fd;
}

#if HAVE_PTHREAD_CANCEL
static void *circular_buffer_task_rx( void *_URLContext)
{
    URLContext *h = _URLContext;
    UDPContext *s = h->priv_data;
    int old_cancelstate;

    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &old_cancelstate);
    pthread_mutex_lock(&s->mutex);
    if (ff_socket_nonblock(s->udp_fd, 0) < 0) {
        av_log(h, AV_LOG_ERROR, "Failed to set blocking mode");
        s->circular_buffer_error = AVERROR(EIO);
        goto end;
    }
    while(1) {
        int len;

        pthread_mutex_unlock(&s->mutex);
        /* Blocking operations are always cancellation points;
           see "General Information" / "Thread Cancelation Overview"
           in Single Unix. */
        pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &old_cancelstate);
        len = recv(s->udp_fd, s->tmp+4, sizeof(s->tmp)-4, 0);
        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &old_cancelstate);
        pthread_mutex_lock(&s->mutex);
        if (len < 0) {
            if (ff_neterrno() != AVERROR(EAGAIN) && ff_neterrno() != AVERROR(EINTR)) {
                s->circular_buffer_error = ff_neterrno();
                goto end;
            }
            continue;
        }
        AV_WL32(s->tmp, len);

        if(av_fifo_space(s->fifo) < len + 4) {
            /* No Space left */
            if (s->overrun_nonfatal) {
                av_log(h, AV_LOG_WARNING, "Circular buffer overrun. "
                        "Surviving due to overrun_nonfatal option\n");
                continue;
            } else {
                av_log(h, AV_LOG_ERROR, "Circular buffer overrun. "
                        "To avoid, increase fifo_size URL option. "
                        "To survive in such case, use overrun_nonfatal option\n");
                s->circular_buffer_error = AVERROR(EIO);
                goto end;
            }
        }
        av_fifo_generic_write(s->fifo, s->tmp, len+4, NULL);
        pthread_cond_signal(&s->cond);
    }

end:
    pthread_cond_signal(&s->cond);
    pthread_mutex_unlock(&s->mutex);
    return NULL;
}

static void *circular_buffer_task_tx( void *_URLContext)
{
    URLContext *h = _URLContext;
    UDPContext *s = h->priv_data;
    int old_cancelstate;

    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &old_cancelstate);
    pthread_mutex_lock(&s->mutex);

    if (ff_socket_nonblock(s->udp_fd, 0) < 0) {
        av_log(h, AV_LOG_ERROR, "Failed to set blocking mode");
        s->circular_buffer_error = AVERROR(EIO);
        goto end;
    }

    for(;;) {
        int len;
        const uint8_t *p;
        uint8_t tmp[4];

        len=av_fifo_size(s->fifo);

        while (len<4) {
            if (s->close_req)
                goto end;
            if (pthread_cond_wait(&s->cond, &s->mutex) < 0) {
                goto end;
            }
            len=av_fifo_size(s->fifo);
        }

        av_fifo_generic_read(s->fifo, tmp, 4, NULL);
        len=AV_RL32(tmp);

        av_assert0(len >= 0);
        av_assert0(len <= sizeof(s->tmp));

        av_fifo_generic_read(s->fifo, s->tmp, len, NULL);

        pthread_mutex_unlock(&s->mutex);
        pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &old_cancelstate);

        p = s->tmp;
        while (len) {
            int ret;
            av_assert0(len > 0);
            if (!s->is_connected) {
                ret = sendto (s->udp_fd, p, len, 0,
                            (struct sockaddr *) &s->dest_addr,
                            s->dest_addr_len);
            } else
                ret = send(s->udp_fd, p, len, 0);
            if (ret >= 0) {
                len -= ret;
                p   += ret;
            } else {
                ret = ff_neterrno();
                if (ret != AVERROR(EAGAIN) && ret != AVERROR(EINTR)) {
                    pthread_mutex_lock(&s->mutex);
                    s->circular_buffer_error = ret;
                    pthread_mutex_unlock(&s->mutex);
                    return NULL;
                }
            }
        }

        av_usleep(s->packet_gap);

        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &old_cancelstate);
        pthread_mutex_lock(&s->mutex);
    }

end:
    pthread_mutex_unlock(&s->mutex);
    return NULL;
}


#endif

static int parse_source_list(char *buf, char **sources, int *num_sources,
                             int max_sources)
{
    char *source_start;

    source_start = buf;
    while (1) {
        char *next = strchr(source_start, ',');
        if (next)
            *next = '\0';
        sources[*num_sources] = av_strdup(source_start);
        if (!sources[*num_sources])
            return AVERROR(ENOMEM);
        source_start = next + 1;
        (*num_sources)++;
        if (*num_sources >= max_sources || !next)
            break;
    }
    return 0;
}

/* put it in UDP context */
/* return non zero if error */
static int udp_open(URLContext *h, const char *uri, int flags)
{
    char hostname[1024], localaddr[1024] = "";
    int port, udp_fd = -1, tmp, bind_ret = -1, dscp = -1;
    UDPContext *s = h->priv_data;
    int is_output;
    const char *p;
    char buf[256];
    struct sockaddr_storage my_addr;
    socklen_t len;
    int i, num_include_sources = 0, num_exclude_sources = 0;
    char *include_sources[32], *exclude_sources[32];

    h->is_streamed = 1;

    is_output = !(flags & AVIO_FLAG_READ);
    if (s->buffer_size < 0)
        s->buffer_size = is_output ? UDP_TX_BUF_SIZE : UDP_MAX_PKT_SIZE;

    if (s->sources) {
        if (parse_source_list(s->sources, include_sources,
                              &num_include_sources,
                              FF_ARRAY_ELEMS(include_sources)))
            goto fail;
    }

    if (s->block) {
        if (parse_source_list(s->block, exclude_sources, &num_exclude_sources,
                              FF_ARRAY_ELEMS(exclude_sources)))
            goto fail;
    }

    if (s->pkt_size > 0)
        h->max_packet_size = s->pkt_size;

    p = strchr(uri, '?');
    if (p) {
        if (av_find_info_tag(buf, sizeof(buf), "reuse", p)) {
            char *endptr = NULL;
            s->reuse_socket = strtol(buf, &endptr, 10);
            /* assume if no digits were found it is a request to enable it */
            if (buf == endptr)
                s->reuse_socket = 1;
        }
        if (av_find_info_tag(buf, sizeof(buf), "overrun_nonfatal", p)) {
            char *endptr = NULL;
            s->overrun_nonfatal = strtol(buf, &endptr, 10);
            /* assume if no digits were found it is a request to enable it */
            if (buf == endptr)
                s->overrun_nonfatal = 1;
            if (!HAVE_PTHREAD_CANCEL)
                av_log(h, AV_LOG_WARNING,
                       "'overrun_nonfatal' option was set but it is not supported "
                       "on this build (pthread support is required)\n");
        }
        if (av_find_info_tag(buf, sizeof(buf), "ttl", p)) {
            s->ttl = strtol(buf, NULL, 10);
        }
        if (av_find_info_tag(buf, sizeof(buf), "udplite_coverage", p)) {
            s->udplite_coverage = strtol(buf, NULL, 10);
        }
        if (av_find_info_tag(buf, sizeof(buf), "localport", p)) {
            s->local_port = strtol(buf, NULL, 10);
        }
        if (av_find_info_tag(buf, sizeof(buf), "pkt_size", p)) {
            s->pkt_size = strtol(buf, NULL, 10);
        }
        if (av_find_info_tag(buf, sizeof(buf), "buffer_size", p)) {
            s->buffer_size = strtol(buf, NULL, 10);
        }
        if (av_find_info_tag(buf, sizeof(buf), "connect", p)) {
            s->is_connected = strtol(buf, NULL, 10);
        }
        if (av_find_info_tag(buf, sizeof(buf), "dscp", p)) {
            dscp = strtol(buf, NULL, 10);
        }
        if (av_find_info_tag(buf, sizeof(buf), "fifo_size", p)) {
            s->circular_buffer_size = strtol(buf, NULL, 10);
            if (!HAVE_PTHREAD_CANCEL)
                av_log(h, AV_LOG_WARNING,
                       "'circular_buffer_size' option was set but it is not supported "
                       "on this build (pthread support is required)\n");
        }
        if (av_find_info_tag(buf, sizeof(buf), "packet_gap", p)) {
            if (av_parse_time(&s->packet_gap, buf, 1)<0) {
                av_log(h, AV_LOG_ERROR, "Can't parse 'packet_gap'");
                goto fail;
            }
            if (!HAVE_PTHREAD_CANCEL)
                av_log(h, AV_LOG_WARNING,
                       "'packet_gap' option was set but it is not supported "
                       "on this build (pthread support is required)\n");
        }
        if (av_find_info_tag(buf, sizeof(buf), "localaddr", p)) {
            av_strlcpy(localaddr, buf, sizeof(localaddr));
        }
        if (av_find_info_tag(buf, sizeof(buf), "sources", p)) {
            if (parse_source_list(buf, include_sources, &num_include_sources,
                                  FF_ARRAY_ELEMS(include_sources)))
                goto fail;
        }
        if (av_find_info_tag(buf, sizeof(buf), "block", p)) {
            if (parse_source_list(buf, exclude_sources, &num_exclude_sources,
                                  FF_ARRAY_ELEMS(exclude_sources)))
                goto fail;
        }
        if (!is_output && av_find_info_tag(buf, sizeof(buf), "timeout", p))
            s->timeout = strtol(buf, NULL, 10);
        if (is_output && av_find_info_tag(buf, sizeof(buf), "broadcast", p))
            s->is_broadcast = strtol(buf, NULL, 10);
    }
    /* handling needed to support options picking from both AVOption and URL */
    s->circular_buffer_size *= 188;
    if (flags & AVIO_FLAG_WRITE) {
        h->max_packet_size = s->pkt_size;
    } else {
        h->max_packet_size = UDP_MAX_PKT_SIZE;
    }
    h->rw_timeout = s->timeout;

    /* fill the dest addr */
    av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port, NULL, 0, uri);

    /* XXX: fix av_url_split */
    if (hostname[0] == '\0' || hostname[0] == '?') {
        /* only accepts null hostname if input */
        if (!(flags & AVIO_FLAG_READ))
            goto fail;
    } else {
        if (ff_udp_set_remote_url(h, uri) < 0)
            goto fail;
    }

    if ((s->is_multicast || s->local_port <= 0) && (h->flags & AVIO_FLAG_READ))
        s->local_port = port;

    if (localaddr[0])
        udp_fd = udp_socket_create(h, &my_addr, &len, localaddr);
    else
        udp_fd = udp_socket_create(h, &my_addr, &len, s->localaddr);
    if (udp_fd < 0)
        goto fail;

    s->local_addr_storage=my_addr; //store for future multicast join

    /* Follow the requested reuse option, unless it's multicast in which
     * case enable reuse unless explicitly disabled.
     */
    if (s->reuse_socket > 0 || (s->is_multicast && s->reuse_socket < 0)) {
        s->reuse_socket = 1;
        if (setsockopt (udp_fd, SOL_SOCKET, SO_REUSEADDR, &(s->reuse_socket), sizeof(s->reuse_socket)) != 0)
            goto fail;
    }

    if (s->is_broadcast) {
#ifdef SO_BROADCAST
        if (setsockopt (udp_fd, SOL_SOCKET, SO_BROADCAST, &(s->is_broadcast), sizeof(s->is_broadcast)) != 0)
#endif
           goto fail;
    }

    /* Set the checksum coverage for UDP-Lite (RFC 3828) for sending and receiving.
     * The receiver coverage has to be less than or equal to the sender coverage.
     * Otherwise, the receiver will drop all packets.
     */
    if (s->udplite_coverage) {
        if (setsockopt (udp_fd, IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV, &(s->udplite_coverage), sizeof(s->udplite_coverage)) != 0)
            av_log(h, AV_LOG_WARNING, "socket option UDPLITE_SEND_CSCOV not available");

        if (setsockopt (udp_fd, IPPROTO_UDPLITE, UDPLITE_RECV_CSCOV, &(s->udplite_coverage), sizeof(s->udplite_coverage)) != 0)
            av_log(h, AV_LOG_WARNING, "socket option UDPLITE_RECV_CSCOV not available");
    }

    if (dscp >= 0) {
        dscp <<= 2;
        if (setsockopt (udp_fd, IPPROTO_IP, IP_TOS, &dscp, sizeof(dscp)) != 0)
            goto fail;
    }

    /* If multicast, try binding the multicast address first, to avoid
     * receiving UDP packets from other sources aimed at the same UDP
     * port. This fails on windows. This makes sending to the same address
     * using sendto() fail, so only do it if we're opened in read-only mode. */
    if (s->is_multicast && !(h->flags & AVIO_FLAG_WRITE)) {
        bind_ret = bind(udp_fd,(struct sockaddr *)&s->dest_addr, len);
    }
    /* bind to the local address if not multicast or if the multicast
     * bind failed */
    /* the bind is needed to give a port to the socket now */
    if (bind_ret < 0 && bind(udp_fd,(struct sockaddr *)&my_addr, len) < 0) {
        log_net_error(h, AV_LOG_ERROR, "bind failed");
        goto fail;
    }

    len = sizeof(my_addr);
    getsockname(udp_fd, (struct sockaddr *)&my_addr, &len);
    s->local_port = udp_port(&my_addr, len);

    if (s->is_multicast) {
        if (h->flags & AVIO_FLAG_WRITE) {
            /* output */
            if (udp_set_multicast_ttl(udp_fd, s->ttl, (struct sockaddr *)&s->dest_addr) < 0)
                goto fail;
        }
        if (h->flags & AVIO_FLAG_READ) {
            /* input */
            if (num_include_sources && num_exclude_sources) {
                av_log(h, AV_LOG_ERROR, "Simultaneously including and excluding multicast sources is not supported\n");
                goto fail;
            }
            if (num_include_sources) {
                if (udp_set_multicast_sources(h, udp_fd,
                                              (struct sockaddr *)&s->dest_addr,
                                              s->dest_addr_len,
                                              include_sources,
                                              num_include_sources, 1) < 0)
                    goto fail;
            } else {
                if (udp_join_multicast_group(udp_fd, (struct sockaddr *)&s->dest_addr,(struct sockaddr *)&s->local_addr_storage) < 0)
                    goto fail;
            }
            if (num_exclude_sources) {
                if (udp_set_multicast_sources(h, udp_fd,
                                              (struct sockaddr *)&s->dest_addr,
                                              s->dest_addr_len,
                                              exclude_sources,
                                              num_exclude_sources, 0) < 0)
                    goto fail;
            }
        }
    }

    if (is_output) {
        /* limit the tx buf size to limit latency */
        tmp = s->buffer_size;
        if (setsockopt(udp_fd, SOL_SOCKET, SO_SNDBUF, &tmp, sizeof(tmp)) < 0) {
            log_net_error(h, AV_LOG_ERROR, "setsockopt(SO_SNDBUF)");
            goto fail;
        }
    } else {
        /* set udp recv buffer size to the requested value (default 64K) */
        tmp = s->buffer_size;
        if (setsockopt(udp_fd, SOL_SOCKET, SO_RCVBUF, &tmp, sizeof(tmp)) < 0) {
            log_net_error(h, AV_LOG_WARNING, "setsockopt(SO_RECVBUF)");
        }
        len = sizeof(tmp);
        if (getsockopt(udp_fd, SOL_SOCKET, SO_RCVBUF, &tmp, &len) < 0) {
            log_net_error(h, AV_LOG_WARNING, "getsockopt(SO_RCVBUF)");
        } else {
            av_log(h, AV_LOG_DEBUG, "end receive buffer size reported is %d\n", tmp);
            if(tmp < s->buffer_size)
                av_log(h, AV_LOG_WARNING, "attempted to set receive buffer to size %d but it only ended up set as %d", s->buffer_size, tmp);
        }

        /* make the socket non-blocking */
        ff_socket_nonblock(udp_fd, 1);
    }
    if (s->is_connected) {
        if (connect(udp_fd, (struct sockaddr *) &s->dest_addr, s->dest_addr_len)) {
            log_net_error(h, AV_LOG_ERROR, "connect");
            goto fail;
        }
    }

    for (i = 0; i < num_include_sources; i++)
        av_freep(&include_sources[i]);
    for (i = 0; i < num_exclude_sources; i++)
        av_freep(&exclude_sources[i]);

    s->udp_fd = udp_fd;

#if HAVE_PTHREAD_CANCEL
    /*
      Create thread in case of:
      1. Input and circular_buffer_size is set
      2. Output and packet_gap and circular_buffer_size is set
    */

    if (is_output && s->packet_gap && !s->circular_buffer_size) {
        /* Warn user in case of 'circular_buffer_size' is not set */
        av_log(h, AV_LOG_WARNING,"'packet_gap' option was set but 'circular_buffer_size' is not, but required\n");
    }

    if ((!is_output && s->circular_buffer_size) || (is_output && s->packet_gap && s->circular_buffer_size)) {
        int ret;

        /* start the task going */
        s->fifo = av_fifo_alloc(s->circular_buffer_size);
        ret = pthread_mutex_init(&s->mutex, NULL);
        if (ret != 0) {
            av_log(h, AV_LOG_ERROR, "pthread_mutex_init failed : %s\n", strerror(ret));
            goto fail;
        }
        ret = pthread_cond_init(&s->cond, NULL);
        if (ret != 0) {
            av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", strerror(ret));
            goto cond_fail;
        }
        ret = pthread_create(&s->circular_buffer_thread, NULL, is_output?circular_buffer_task_tx:circular_buffer_task_rx, h);
        if (ret != 0) {
            av_log(h, AV_LOG_ERROR, "pthread_create failed : %s\n", strerror(ret));
            goto thread_fail;
        }
        s->thread_started = 1;
    }
#endif

    return 0;
#if HAVE_PTHREAD_CANCEL
 thread_fail:
    pthread_cond_destroy(&s->cond);
 cond_fail:
    pthread_mutex_destroy(&s->mutex);
#endif
 fail:
    if (udp_fd >= 0)
        closesocket(udp_fd);
    av_fifo_freep(&s->fifo);
    for (i = 0; i < num_include_sources; i++)
        av_freep(&include_sources[i]);
    for (i = 0; i < num_exclude_sources; i++)
        av_freep(&exclude_sources[i]);
    return AVERROR(EIO);
}

static int udplite_open(URLContext *h, const char *uri, int flags)
{
    UDPContext *s = h->priv_data;

    // set default checksum coverage
    s->udplite_coverage = UDP_HEADER_SIZE;

    return udp_open(h, uri, flags);
}

static int udp_read(URLContext *h, uint8_t *buf, int size)
{
    UDPContext *s = h->priv_data;
    int ret;
#if HAVE_PTHREAD_CANCEL
    int avail, nonblock = h->flags & AVIO_FLAG_NONBLOCK;

    if (s->fifo) {
        pthread_mutex_lock(&s->mutex);
        do {
            avail = av_fifo_size(s->fifo);
            if (avail) { // >=size) {
                uint8_t tmp[4];

                av_fifo_generic_read(s->fifo, tmp, 4, NULL);
                avail= AV_RL32(tmp);
                if(avail > size){
                    av_log(h, AV_LOG_WARNING, "Part of datagram lost due to insufficient buffer size\n");
                    avail= size;
                }

                av_fifo_generic_read(s->fifo, buf, avail, NULL);
                av_fifo_drain(s->fifo, AV_RL32(tmp) - avail);
                pthread_mutex_unlock(&s->mutex);
                return avail;
            } else if(s->circular_buffer_error){
                int err = s->circular_buffer_error;
                pthread_mutex_unlock(&s->mutex);
                return err;
            } else if(nonblock) {
                pthread_mutex_unlock(&s->mutex);
                return AVERROR(EAGAIN);
            }
            else {
                /* FIXME: using the monotonic clock would be better,
                   but it does not exist on all supported platforms. */
                int64_t t = av_gettime() + 100000;
                struct timespec tv = { .tv_sec  =  t / 1000000,
                                       .tv_nsec = (t % 1000000) * 1000 };
                if (pthread_cond_timedwait(&s->cond, &s->mutex, &tv) < 0) {
                    pthread_mutex_unlock(&s->mutex);
                    return AVERROR(errno == ETIMEDOUT ? EAGAIN : errno);
                }
                nonblock = 1;
            }
        } while( 1);
    }
#endif

    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
        ret = ff_network_wait_fd(s->udp_fd, 0);
        if (ret < 0)
            return ret;
    }
    ret = recv(s->udp_fd, buf, size, 0);

    return ret < 0 ? ff_neterrno() : ret;
}

static int udp_write(URLContext *h, const uint8_t *buf, int size)
{
    UDPContext *s = h->priv_data;
    int ret;

#if HAVE_PTHREAD_CANCEL
    if (s->fifo) {
        uint8_t tmp[4];

        pthread_mutex_lock(&s->mutex);

        /*
          Return error if last tx failed.
          Here we can't know on which packet error was, but it needs to know that error exists.
        */
        if (s->circular_buffer_error<0) {
            int err=s->circular_buffer_error;
            pthread_mutex_unlock(&s->mutex);
            return err;
        }

        if(av_fifo_space(s->fifo) < size + 4) {
            /* What about a partial packet tx ? */
            pthread_mutex_unlock(&s->mutex);
            return AVERROR(ENOMEM);
        }
        AV_WL32(tmp, size);
        av_fifo_generic_write(s->fifo, tmp, 4, NULL); /* size of packet */
        av_fifo_generic_write(s->fifo, (uint8_t *)buf, size, NULL); /* the data */
        pthread_cond_signal(&s->cond);
        pthread_mutex_unlock(&s->mutex);
        return size;
    }
#endif
    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
        ret = ff_network_wait_fd(s->udp_fd, 1);
        if (ret < 0)
            return ret;
    }

    if (!s->is_connected) {
        ret = sendto (s->udp_fd, buf, size, 0,
                      (struct sockaddr *) &s->dest_addr,
                      s->dest_addr_len);
    } else
        ret = send(s->udp_fd, buf, size, 0);

    return ret < 0 ? ff_neterrno() : ret;
}

static int udp_close(URLContext *h)
{
    UDPContext *s = h->priv_data;

#if HAVE_PTHREAD_CANCEL
    // Request close once writing is finished
    if (s->thread_started && !(h->flags & AVIO_FLAG_READ)) {
        pthread_mutex_lock(&s->mutex);
        s->close_req = 1;
        pthread_cond_signal(&s->cond);
        pthread_mutex_unlock(&s->mutex);
    }
#endif

    if (s->is_multicast && (h->flags & AVIO_FLAG_READ))
        udp_leave_multicast_group(s->udp_fd, (struct sockaddr *)&s->dest_addr,(struct sockaddr *)&s->local_addr_storage);
#if HAVE_PTHREAD_CANCEL
    if (s->thread_started) {
        int ret;
        // Cancel only read, as write has been signaled as success to the user
        if (h->flags & AVIO_FLAG_READ)
            pthread_cancel(s->circular_buffer_thread);
        ret = pthread_join(s->circular_buffer_thread, NULL);
        if (ret != 0)
            av_log(h, AV_LOG_ERROR, "pthread_join(): %s\n", strerror(ret));
        pthread_mutex_destroy(&s->mutex);
        pthread_cond_destroy(&s->cond);
    }
#endif
    closesocket(s->udp_fd);
    av_fifo_freep(&s->fifo);
    return 0;
}

const URLProtocol ff_udp_protocol = {
    .name                = "udp",
    .url_open            = udp_open,
    .url_read            = udp_read,
    .url_write           = udp_write,
    .url_close           = udp_close,
    .url_get_file_handle = udp_get_file_handle,
    .priv_data_size      = sizeof(UDPContext),
    .priv_data_class     = &udp_class,
    .flags               = URL_PROTOCOL_FLAG_NETWORK,
};

const URLProtocol ff_udplite_protocol = {
    .name                = "udplite",
    .url_open            = udplite_open,
    .url_read            = udp_read,
    .url_write           = udp_write,
    .url_close           = udp_close,
    .url_get_file_handle = udp_get_file_handle,
    .priv_data_size      = sizeof(UDPContext),
    .priv_data_class     = &udplite_context_class,
    .flags               = URL_PROTOCOL_FLAG_NETWORK,
};