summaryrefslogtreecommitdiff
path: root/toxcore/network.c
blob: 31e8fd8bd3d4e2b8ab872bfdb615d460864be6e8 (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
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
/* network.c
 *
 * Functions for the core networking.
 *
 *  Copyright (C) 2013 Tox project All Rights Reserved.
 *
 *  This file is part of Tox.
 *
 *  Tox is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Tox is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Tox.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#if defined(_WIN32) && _WIN32_WINNT >= _WIN32_WINNT_WINXP
#define _WIN32_WINNT  0x501
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "network.h"

#include "logger.h"
#include "util.h"

#if !defined(_WIN32) && !defined(__WIN32__) && !defined (WIN32)
#include <errno.h>
#endif

#ifdef __APPLE__
#include <mach/clock.h>
#include <mach/mach.h>
#endif

#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)

static const char *inet_ntop(sa_family_t family, const void *addr, char *buf, size_t bufsize)
{
    if (family == AF_INET) {
        struct sockaddr_in saddr;
        memset(&saddr, 0, sizeof(saddr));

        saddr.sin_family = AF_INET;
        saddr.sin_addr = *(const struct in_addr *)addr;

        DWORD len = bufsize;

        if (WSAAddressToString((LPSOCKADDR)&saddr, sizeof(saddr), NULL, buf, &len)) {
            return NULL;
        }

        return buf;
    } else if (family == AF_INET6) {
        struct sockaddr_in6 saddr;
        memset(&saddr, 0, sizeof(saddr));

        saddr.sin6_family = AF_INET6;
        saddr.sin6_addr = *(const struct in6_addr *)addr;

        DWORD len = bufsize;

        if (WSAAddressToString((LPSOCKADDR)&saddr, sizeof(saddr), NULL, buf, &len)) {
            return NULL;
        }

        return buf;
    }

    return NULL;
}

static int inet_pton(sa_family_t family, const char *addrString, void *addrbuf)
{
    if (family == AF_INET) {
        struct sockaddr_in saddr;
        memset(&saddr, 0, sizeof(saddr));

        INT len = sizeof(saddr);

        if (WSAStringToAddress((LPTSTR)addrString, AF_INET, NULL, (LPSOCKADDR)&saddr, &len)) {
            return 0;
        }

        *(struct in_addr *)addrbuf = saddr.sin_addr;

        return 1;
    } else if (family == AF_INET6) {
        struct sockaddr_in6 saddr;
        memset(&saddr, 0, sizeof(saddr));

        INT len = sizeof(saddr);

        if (WSAStringToAddress((LPTSTR)addrString, AF_INET6, NULL, (LPSOCKADDR)&saddr, &len)) {
            return 0;
        }

        *(struct in6_addr *)addrbuf = saddr.sin6_addr;

        return 1;
    }

    return 0;
}

#endif

/* Check if socket is valid.
 *
 * return 1 if valid
 * return 0 if not valid
 */
int sock_valid(sock_t sock)
{
#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)

    if (sock == INVALID_SOCKET) {
#else

    if (sock < 0) {
#endif
        return 0;
    }

    return 1;
}

/* Close the socket.
 */
void kill_sock(sock_t sock)
{
#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
    closesocket(sock);
#else
    close(sock);
#endif
}

/* Set socket as nonblocking
 *
 * return 1 on success
 * return 0 on failure
 */
int set_socket_nonblock(sock_t sock)
{
#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
    u_long mode = 1;
    return (ioctlsocket(sock, FIONBIO, &mode) == 0);
#else
    return (fcntl(sock, F_SETFL, O_NONBLOCK, 1) == 0);
#endif
}

/* Set socket to not emit SIGPIPE
 *
 * return 1 on success
 * return 0 on failure
 */
int set_socket_nosigpipe(sock_t sock)
{
#if defined(__MACH__)
    int set = 1;
    return (setsockopt(sock, SOL_SOCKET, SO_NOSIGPIPE, (const char *)&set, sizeof(int)) == 0);
#else
    return 1;
#endif
}

/* Enable SO_REUSEADDR on socket.
 *
 * return 1 on success
 * return 0 on failure
 */
int set_socket_reuseaddr(sock_t sock)
{
    int set = 1;
    return (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char *)&set, sizeof(set)) == 0);
}

/* Set socket to dual (IPv4 + IPv6 socket)
 *
 * return 1 on success
 * return 0 on failure
 */
int set_socket_dualstack(sock_t sock)
{
    int ipv6only = 0;
    socklen_t optsize = sizeof(ipv6only);
    int res = getsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&ipv6only, &optsize);

    if ((res == 0) && (ipv6only == 0)) {
        return 1;
    }

    ipv6only = 0;
    return (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char *)&ipv6only, sizeof(ipv6only)) == 0);
}


/*  return current UNIX time in microseconds (us). */
static uint64_t current_time_actual(void)
{
    uint64_t time;
#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
    /* This probably works fine */
    FILETIME ft;
    GetSystemTimeAsFileTime(&ft);
    time = ft.dwHighDateTime;
    time <<= 32;
    time |= ft.dwLowDateTime;
    time -= 116444736000000000ULL;
    return time / 10;
#else
    struct timeval a;
    gettimeofday(&a, NULL);
    time = 1000000ULL * a.tv_sec + a.tv_usec;
    return time;
#endif
}


#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
static uint64_t last_monotime;
static uint64_t add_monotime;
#endif

/* return current monotonic time in milliseconds (ms). */
uint64_t current_time_monotonic(void)
{
    uint64_t time;
#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
    time = (uint64_t)GetTickCount() + add_monotime;

    if (time < last_monotime) { /* Prevent time from ever decreasing because of 32 bit wrap. */
        uint32_t add = ~0;
        add_monotime += add;
        time += add;
    }

    last_monotime = time;
#else
    struct timespec monotime;
#if defined(__linux__) && defined(CLOCK_MONOTONIC_RAW)
    clock_gettime(CLOCK_MONOTONIC_RAW, &monotime);
#elif defined(__APPLE__)
    clock_serv_t muhclock;
    mach_timespec_t machtime;

    host_get_clock_service(mach_host_self(), SYSTEM_CLOCK, &muhclock);
    clock_get_time(muhclock, &machtime);
    mach_port_deallocate(mach_task_self(), muhclock);

    monotime.tv_sec = machtime.tv_sec;
    monotime.tv_nsec = machtime.tv_nsec;
#else
    clock_gettime(CLOCK_MONOTONIC, &monotime);
#endif
    time = 1000ULL * monotime.tv_sec + (monotime.tv_nsec / 1000000ULL);
#endif
    return time;
}

static uint32_t data_0(uint16_t buflen, const uint8_t *buffer)
{
    return buflen > 4 ? ntohl(*(const uint32_t *)&buffer[1]) : 0;
}
static uint32_t data_1(uint16_t buflen, const uint8_t *buffer)
{
    return buflen > 7 ? ntohl(*(const uint32_t *)&buffer[5]) : 0;
}

static void loglogdata(Logger *log, const char *message, const uint8_t *buffer,
                       uint16_t buflen, IP_Port ip_port, int res)
{
    if (res < 0) { /* Windows doesn't necessarily know %zu */
        LOGGER_TRACE(log, "[%2u] %s %3hu%c %s:%hu (%u: %s) | %04x%04x",
                     buffer[0], message, (buflen < 999 ? (uint16_t)buflen : 999), 'E',
                     ip_ntoa(&ip_port.ip), ntohs(ip_port.port), errno, strerror(errno), data_0(buflen, buffer),
                     data_1(buflen, buffer));
    } else if ((res > 0) && ((size_t)res <= buflen)) {
        LOGGER_TRACE(log, "[%2u] %s %3zu%c %s:%hu (%u: %s) | %04x%04x",
                     buffer[0], message, (res < 999 ? (size_t)res : 999), ((size_t)res < buflen ? '<' : '='),
                     ip_ntoa(&ip_port.ip), ntohs(ip_port.port), 0, "OK", data_0(buflen, buffer), data_1(buflen,
                             buffer));
    } else { /* empty or overwrite */
        LOGGER_TRACE(log, "[%2u] %s %zu%c%zu %s:%hu (%u: %s) | %04x%04x",
                     buffer[0], message, (size_t)res, (!res ? '!' : '>'), buflen,
                     ip_ntoa(&ip_port.ip), ntohs(ip_port.port), 0, "OK", data_0(buflen, buffer), data_1(buflen,
                             buffer));
    }
}


/* Basic network functions:
 * Function to send packet(data) of length length to ip_port.
 */
int sendpacket(Networking_Core *net, IP_Port ip_port, const uint8_t *data, uint16_t length)
{
    if (net->family == 0) { /* Socket not initialized */
        return -1;
    }

    /* socket AF_INET, but target IP NOT: can't send */
    if ((net->family == AF_INET) && (ip_port.ip.family != AF_INET)) {
        return -1;
    }

    struct sockaddr_storage addr;

    size_t addrsize = 0;

    if (ip_port.ip.family == AF_INET) {
        if (net->family == AF_INET6) {
            /* must convert to IPV4-in-IPV6 address */
            struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&addr;

            addrsize = sizeof(struct sockaddr_in6);
            addr6->sin6_family = AF_INET6;
            addr6->sin6_port = ip_port.port;

            /* there should be a macro for this in a standards compliant
             * environment, not found */
            IP6 ip6;

            ip6.uint32[0] = 0;
            ip6.uint32[1] = 0;
            ip6.uint32[2] = htonl(0xFFFF);
            ip6.uint32[3] = ip_port.ip.ip4.uint32;
            addr6->sin6_addr = ip6.in6_addr;

            addr6->sin6_flowinfo = 0;
            addr6->sin6_scope_id = 0;
        } else {
            struct sockaddr_in *addr4 = (struct sockaddr_in *)&addr;

            addrsize = sizeof(struct sockaddr_in);
            addr4->sin_family = AF_INET;
            addr4->sin_addr = ip_port.ip.ip4.in_addr;
            addr4->sin_port = ip_port.port;
        }
    } else if (ip_port.ip.family == AF_INET6) {
        struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&addr;

        addrsize = sizeof(struct sockaddr_in6);
        addr6->sin6_family = AF_INET6;
        addr6->sin6_port = ip_port.port;
        addr6->sin6_addr = ip_port.ip.ip6.in6_addr;

        addr6->sin6_flowinfo = 0;
        addr6->sin6_scope_id = 0;
    } else {
        /* unknown address type*/
        return -1;
    }

    int res = sendto(net->sock, (const char *) data, length, 0, (struct sockaddr *)&addr, addrsize);

    loglogdata(net->log, "O=>", data, length, ip_port, res);

    return res;
}

/* Function to receive data
 *  ip and port of sender is put into ip_port.
 *  Packet data is put into data.
 *  Packet length is put into length.
 */
static int receivepacket(Logger *log, sock_t sock, IP_Port *ip_port, uint8_t *data, uint32_t *length)
{
    memset(ip_port, 0, sizeof(IP_Port));
    struct sockaddr_storage addr;
#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
    int addrlen = sizeof(addr);
#else
    socklen_t addrlen = sizeof(addr);
#endif
    *length = 0;
    int fail_or_len = recvfrom(sock, (char *) data, MAX_UDP_PACKET_SIZE, 0, (struct sockaddr *)&addr, &addrlen);

    if (fail_or_len < 0) {

        if (fail_or_len < 0 && errno != EWOULDBLOCK) {
            LOGGER_ERROR(log, "Unexpected error reading from socket: %u, %s\n", errno, strerror(errno));
        }

        return -1; /* Nothing received. */
    }

    *length = (uint32_t)fail_or_len;

    if (addr.ss_family == AF_INET) {
        struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;

        ip_port->ip.family = addr_in->sin_family;
        ip_port->ip.ip4.in_addr = addr_in->sin_addr;
        ip_port->port = addr_in->sin_port;
    } else if (addr.ss_family == AF_INET6) {
        struct sockaddr_in6 *addr_in6 = (struct sockaddr_in6 *)&addr;
        ip_port->ip.family = addr_in6->sin6_family;
        ip_port->ip.ip6.in6_addr = addr_in6->sin6_addr;
        ip_port->port = addr_in6->sin6_port;

        if (IPV6_IPV4_IN_V6(ip_port->ip.ip6)) {
            ip_port->ip.family = AF_INET;
            ip_port->ip.ip4.uint32 = ip_port->ip.ip6.uint32[3];
        }
    } else {
        return -1;
    }

    loglogdata(log, "=>O", data, MAX_UDP_PACKET_SIZE, *ip_port, *length);

    return 0;
}

void networking_registerhandler(Networking_Core *net, uint8_t byte, packet_handler_callback cb, void *object)
{
    net->packethandlers[byte].function = cb;
    net->packethandlers[byte].object = object;
}

void networking_poll(Networking_Core *net, void *userdata)
{
    if (net->family == 0) { /* Socket not initialized */
        return;
    }

    unix_time_update();

    IP_Port ip_port;
    uint8_t data[MAX_UDP_PACKET_SIZE];
    uint32_t length;

    while (receivepacket(net->log, net->sock, &ip_port, data, &length) != -1) {
        if (length < 1) {
            continue;
        }

        if (!(net->packethandlers[data[0]].function)) {
            LOGGER_WARNING(net->log, "[%02u] -- Packet has no handler", data[0]);
            continue;
        }

        net->packethandlers[data[0]].function(net->packethandlers[data[0]].object, ip_port, data, length, userdata);
    }
}

#ifndef VANILLA_NACL
/* Used for sodium_init() */
#include <sodium.h>
#endif

static uint8_t at_startup_ran = 0;
int networking_at_startup(void)
{
    if (at_startup_ran != 0) {
        return 0;
    }

#ifndef VANILLA_NACL

#ifdef USE_RANDOMBYTES_STIR
    randombytes_stir();
#else

    if (sodium_init() == -1) {
        return -1;
    }

#endif /*USE_RANDOMBYTES_STIR*/

#endif/*VANILLA_NACL*/

#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
    WSADATA wsaData;

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != NO_ERROR) {
        return -1;
    }

#endif
    srand((uint32_t)current_time_actual());
    at_startup_ran = 1;
    return 0;
}

/* TODO(irungentoo): Put this somewhere */
#if 0
static void at_shutdown(void)
{
#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
    WSACleanup();
#endif
}
#endif

/* Initialize networking.
 * Added for reverse compatibility with old new_networking calls.
 */
Networking_Core *new_networking(Logger *log, IP ip, uint16_t port)
{
    return new_networking_ex(log, ip, port, port + (TOX_PORTRANGE_TO - TOX_PORTRANGE_FROM), 0);
}

/* Initialize networking.
 * Bind to ip and port.
 * ip must be in network order EX: 127.0.0.1 = (7F000001).
 * port is in host byte order (this means don't worry about it).
 *
 *  return Networking_Core object if no problems
 *  return NULL if there are problems.
 *
 * If error is non NULL it is set to 0 if no issues, 1 if socket related error, 2 if other.
 */
Networking_Core *new_networking_ex(Logger *log, IP ip, uint16_t port_from, uint16_t port_to, unsigned int *error)
{
    /* If both from and to are 0, use default port range
     * If one is 0 and the other is non-0, use the non-0 value as only port
     * If from > to, swap
     */
    if (port_from == 0 && port_to == 0) {
        port_from = TOX_PORTRANGE_FROM;
        port_to = TOX_PORTRANGE_TO;
    } else if (port_from == 0 && port_to != 0) {
        port_from = port_to;
    } else if (port_from != 0 && port_to == 0) {
        port_to = port_from;
    } else if (port_from > port_to) {
        uint16_t temp = port_from;
        port_from = port_to;
        port_to = temp;
    }

    if (error) {
        *error = 2;
    }

    /* maybe check for invalid IPs like 224+.x.y.z? if there is any IP set ever */
    if (ip.family != AF_INET && ip.family != AF_INET6) {
#ifdef TOX_DEBUG
        fprintf(stderr, "Invalid address family: %u\n", ip.family);
#endif
        return NULL;
    }

    if (networking_at_startup() != 0) {
        return NULL;
    }

    Networking_Core *temp = (Networking_Core *)calloc(1, sizeof(Networking_Core));

    if (temp == NULL) {
        return NULL;
    }

    temp->log = log;
    temp->family = ip.family;
    temp->port = 0;

    /* Initialize our socket. */
    /* add log message what we're creating */
    temp->sock = socket(temp->family, SOCK_DGRAM, IPPROTO_UDP);

    /* Check for socket error. */
    if (!sock_valid(temp->sock)) {
#ifdef TOX_DEBUG
        fprintf(stderr, "Failed to get a socket?! %u, %s\n", errno, strerror(errno));
#endif
        free(temp);

        if (error) {
            *error = 1;
        }

        return NULL;
    }

    /* Functions to increase the size of the send and receive UDP buffers.
     */
    int n = 1024 * 1024 * 2;
    setsockopt(temp->sock, SOL_SOCKET, SO_RCVBUF, (const char *)&n, sizeof(n));
    setsockopt(temp->sock, SOL_SOCKET, SO_SNDBUF, (const char *)&n, sizeof(n));

    /* Enable broadcast on socket */
    int broadcast = 1;
    setsockopt(temp->sock, SOL_SOCKET, SO_BROADCAST, (const char *)&broadcast, sizeof(broadcast));

    /* iOS UDP sockets are weird and apparently can SIGPIPE */
    if (!set_socket_nosigpipe(temp->sock)) {
        kill_networking(temp);

        if (error) {
            *error = 1;
        }

        return NULL;
    }

    /* Set socket nonblocking. */
    if (!set_socket_nonblock(temp->sock)) {
        kill_networking(temp);

        if (error) {
            *error = 1;
        }

        return NULL;
    }

    /* Bind our socket to port PORT and the given IP address (usually 0.0.0.0 or ::) */
    uint16_t *portptr = NULL;
    struct sockaddr_storage addr;
    size_t addrsize;

    if (temp->family == AF_INET) {
        struct sockaddr_in *addr4 = (struct sockaddr_in *)&addr;

        addrsize = sizeof(struct sockaddr_in);
        addr4->sin_family = AF_INET;
        addr4->sin_port = 0;
        addr4->sin_addr = ip.ip4.in_addr;

        portptr = &addr4->sin_port;
    } else if (temp->family == AF_INET6) {
        struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&addr;

        addrsize = sizeof(struct sockaddr_in6);
        addr6->sin6_family = AF_INET6;
        addr6->sin6_port = 0;
        addr6->sin6_addr = ip.ip6.in6_addr;

        addr6->sin6_flowinfo = 0;
        addr6->sin6_scope_id = 0;

        portptr = &addr6->sin6_port;
    } else {
        free(temp);
        return NULL;
    }

    if (ip.family == AF_INET6) {
        int is_dualstack = set_socket_dualstack(temp->sock);
        LOGGER_DEBUG(log, "Dual-stack socket: %s",
                     is_dualstack ? "enabled" : "Failed to enable, won't be able to receive from/send to IPv4 addresses");
        /* multicast local nodes */
        struct ipv6_mreq mreq;
        memset(&mreq, 0, sizeof(mreq));
        mreq.ipv6mr_multiaddr.s6_addr[ 0] = 0xFF;
        mreq.ipv6mr_multiaddr.s6_addr[ 1] = 0x02;
        mreq.ipv6mr_multiaddr.s6_addr[15] = 0x01;
        mreq.ipv6mr_interface = 0;
        int res = setsockopt(temp->sock, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, (const char *)&mreq, sizeof(mreq));

        LOGGER_DEBUG(log, res < 0 ? "Failed to activate local multicast membership. (%u, %s)" :
                     "Local multicast group FF02::1 joined successfully", errno, strerror(errno));
    }

    /* a hanging program or a different user might block the standard port;
     * as long as it isn't a parameter coming from the commandline,
     * try a few ports after it, to see if we can find a "free" one
     *
     * if we go on without binding, the first sendto() automatically binds to
     * a free port chosen by the system (i.e. anything from 1024 to 65535)
     *
     * returning NULL after bind fails has both advantages and disadvantages:
     * advantage:
     *   we can rely on getting the port in the range 33445..33450, which
     *   enables us to tell joe user to open their firewall to a small range
     *
     * disadvantage:
     *   some clients might not test return of tox_new(), blindly assuming that
     *   it worked ok (which it did previously without a successful bind)
     */
    uint16_t port_to_try = port_from;
    *portptr = htons(port_to_try);
    int tries;

    for (tries = port_from; tries <= port_to; tries++) {
        int res = bind(temp->sock, (struct sockaddr *)&addr, addrsize);

        if (!res) {
            temp->port = *portptr;

            LOGGER_DEBUG(log, "Bound successfully to %s:%u", ip_ntoa(&ip), ntohs(temp->port));

            /* errno isn't reset on success, only set on failure, the failed
             * binds with parallel clients yield a -EPERM to the outside if
             * errno isn't cleared here */
            if (tries > 0) {
                errno = 0;
            }

            if (error) {
                *error = 0;
            }

            return temp;
        }

        port_to_try++;

        if (port_to_try > port_to) {
            port_to_try = port_from;
        }

        *portptr = htons(port_to_try);
    }

    LOGGER_ERROR(log, "Failed to bind socket: %u, %s IP: %s port_from: %u port_to: %u", errno, strerror(errno),
                 ip_ntoa(&ip), port_from, port_to);

    kill_networking(temp);

    if (error) {
        *error = 1;
    }

    return NULL;
}

/* Function to cleanup networking stuff. */
void kill_networking(Networking_Core *net)
{
    if (!net) {
        return;
    }

    if (net->family != 0) { /* Socket not initialized */
        kill_sock(net->sock);
    }

    free(net);
}


/* ip_equal
 *  compares two IPAny structures
 *  unset means unequal
 *
 * returns 0 when not equal or when uninitialized
 */
int ip_equal(const IP *a, const IP *b)
{
    if (!a || !b) {
        return 0;
    }

    /* same family */
    if (a->family == b->family) {
        if (a->family == AF_INET) {
            return (a->ip4.in_addr.s_addr == b->ip4.in_addr.s_addr);
        }

        if (a->family == AF_INET6) {
            return a->ip6.uint64[0] == b->ip6.uint64[0] && a->ip6.uint64[1] == b->ip6.uint64[1];
        }

        return 0;
    }

    /* different family: check on the IPv6 one if it is the IPv4 one embedded */
    if ((a->family == AF_INET) && (b->family == AF_INET6)) {
        if (IPV6_IPV4_IN_V6(b->ip6)) {
            return (a->ip4.in_addr.s_addr == b->ip6.uint32[3]);
        }
    } else if ((a->family == AF_INET6)  && (b->family == AF_INET)) {
        if (IPV6_IPV4_IN_V6(a->ip6)) {
            return (a->ip6.uint32[3] == b->ip4.in_addr.s_addr);
        }
    }

    return 0;
}

/* ipport_equal
 *  compares two IPAny_Port structures
 *  unset means unequal
 *
 * returns 0 when not equal or when uninitialized
 */
int ipport_equal(const IP_Port *a, const IP_Port *b)
{
    if (!a || !b) {
        return 0;
    }

    if (!a->port || (a->port != b->port)) {
        return 0;
    }

    return ip_equal(&a->ip, &b->ip);
}

/* nulls out ip */
void ip_reset(IP *ip)
{
    if (!ip) {
        return;
    }

    memset(ip, 0, sizeof(IP));
}

/* nulls out ip, sets family according to flag */
void ip_init(IP *ip, uint8_t ipv6enabled)
{
    if (!ip) {
        return;
    }

    memset(ip, 0, sizeof(IP));
    ip->family = ipv6enabled ? AF_INET6 : AF_INET;
}

/* checks if ip is valid */
int ip_isset(const IP *ip)
{
    if (!ip) {
        return 0;
    }

    return (ip->family != 0);
}

/* checks if ip is valid */
int ipport_isset(const IP_Port *ipport)
{
    if (!ipport) {
        return 0;
    }

    if (!ipport->port) {
        return 0;
    }

    return ip_isset(&ipport->ip);
}

/* copies an ip structure (careful about direction!) */
void ip_copy(IP *target, const IP *source)
{
    if (!source || !target) {
        return;
    }

    memcpy(target, source, sizeof(IP));
}

/* copies an ip_port structure (careful about direction!) */
void ipport_copy(IP_Port *target, const IP_Port *source)
{
    if (!source || !target) {
        return;
    }

    memcpy(target, source, sizeof(IP_Port));
}

/* ip_ntoa
 *   converts ip into a string
 *   uses a static buffer, so mustn't used multiple times in the same output
 *
 *   IPv6 addresses are enclosed into square brackets, i.e. "[IPv6]"
 *   writes error message into the buffer on error
 */
/* there would be INET6_ADDRSTRLEN, but it might be too short for the error message */
static char addresstext[96]; // TODO(irungentoo): magic number. Why not INET6_ADDRSTRLEN ?
const char *ip_ntoa(const IP *ip)
{
    if (ip) {
        if (ip->family == AF_INET) {
            /* returns standard quad-dotted notation */
            const struct in_addr *addr = (const struct in_addr *)&ip->ip4;

            addresstext[0] = 0;
            inet_ntop(ip->family, addr, addresstext, sizeof(addresstext));
        } else if (ip->family == AF_INET6) {
            /* returns hex-groups enclosed into square brackets */
            const struct in6_addr *addr = (const struct in6_addr *)&ip->ip6;

            addresstext[0] = '[';
            inet_ntop(ip->family, addr, &addresstext[1], sizeof(addresstext) - 3);
            size_t len = strlen(addresstext);
            addresstext[len] = ']';
            addresstext[len + 1] = 0;
        } else {
            snprintf(addresstext, sizeof(addresstext), "(IP invalid, family %u)", ip->family);
        }
    } else {
        snprintf(addresstext, sizeof(addresstext), "(IP invalid: NULL)");
    }

    /* brute force protection against lacking termination */
    addresstext[sizeof(addresstext) - 1] = 0;
    return addresstext;
}

/*
 * ip_parse_addr
 *  parses IP structure into an address string
 *
 * input
 *  ip: ip of AF_INET or AF_INET6 families
 *  length: length of the address buffer
 *          Must be at least INET_ADDRSTRLEN for AF_INET
 *          and INET6_ADDRSTRLEN for AF_INET6
 *
 * output
 *  address: dotted notation (IPv4: quad, IPv6: 16) or colon notation (IPv6)
 *
 * returns 1 on success, 0 on failure
 */
int ip_parse_addr(const IP *ip, char *address, size_t length)
{
    if (!address || !ip) {
        return 0;
    }

    if (ip->family == AF_INET) {
        const struct in_addr *addr = (const struct in_addr *)&ip->ip4;
        return inet_ntop(ip->family, addr, address, length) != NULL;
    }

    if (ip->family == AF_INET6) {
        const struct in6_addr *addr = (const struct in6_addr *)&ip->ip6;
        return inet_ntop(ip->family, addr, address, length) != NULL;
    }

    return 0;
}

/*
 * addr_parse_ip
 *  directly parses the input into an IP structure
 *  tries IPv4 first, then IPv6
 *
 * input
 *  address: dotted notation (IPv4: quad, IPv6: 16) or colon notation (IPv6)
 *
 * output
 *  IP: family and the value is set on success
 *
 * returns 1 on success, 0 on failure
 */
int addr_parse_ip(const char *address, IP *to)
{
    if (!address || !to) {
        return 0;
    }

    struct in_addr addr4;

    if (1 == inet_pton(AF_INET, address, &addr4)) {
        to->family = AF_INET;
        to->ip4.in_addr = addr4;
        return 1;
    }

    struct in6_addr addr6;

    if (1 == inet_pton(AF_INET6, address, &addr6)) {
        to->family = AF_INET6;
        to->ip6.in6_addr = addr6;
        return 1;
    }

    return 0;
}

/*
 * addr_resolve():
 *  uses getaddrinfo to resolve an address into an IP address
 *  uses the first IPv4/IPv6 addresses returned by getaddrinfo
 *
 * input
 *  address: a hostname (or something parseable to an IP address)
 *  to: to.family MUST be initialized, either set to a specific IP version
 *     (AF_INET/AF_INET6) or to the unspecified AF_UNSPEC (= 0), if both
 *     IP versions are acceptable
 *  extra can be NULL and is only set in special circumstances, see returns
 *
 * returns in *to a valid IPAny (v4/v6),
 *     prefers v6 if ip.family was AF_UNSPEC and both available
 * returns in *extra an IPv4 address, if family was AF_UNSPEC and *to is AF_INET6
 * returns 0 on failure, TOX_ADDR_RESOLVE_* on success.
 */
int addr_resolve(const char *address, IP *to, IP *extra)
{
    if (!address || !to) {
        return 0;
    }

    sa_family_t family = to->family;

    struct addrinfo *server = NULL;
    struct addrinfo *walker = NULL;
    struct addrinfo  hints;
    int rc;
    int result = 0;
    int done = 0;

    memset(&hints, 0, sizeof(hints));
    hints.ai_family   = family;
    hints.ai_socktype = SOCK_DGRAM; // type of socket Tox uses.

    if (networking_at_startup() != 0) {
        return 0;
    }

    rc = getaddrinfo(address, NULL, &hints, &server);

    // Lookup failed.
    if (rc != 0) {
        return 0;
    }

    IP ip4;
    ip_init(&ip4, 0); // ipv6enabled = 0
    IP ip6;
    ip_init(&ip6, 1); // ipv6enabled = 1

    for (walker = server; (walker != NULL) && !done; walker = walker->ai_next) {
        switch (walker->ai_family) {
            case AF_INET:
                if (walker->ai_family == family) { /* AF_INET requested, done */
                    struct sockaddr_in *addr = (struct sockaddr_in *)walker->ai_addr;
                    to->ip4.in_addr = addr->sin_addr;
                    result = TOX_ADDR_RESOLVE_INET;
                    done = 1;
                } else if (!(result & TOX_ADDR_RESOLVE_INET)) { /* AF_UNSPEC requested, store away */
                    struct sockaddr_in *addr = (struct sockaddr_in *)walker->ai_addr;
                    ip4.ip4.in_addr = addr->sin_addr;
                    result |= TOX_ADDR_RESOLVE_INET;
                }

                break; /* switch */

            case AF_INET6:
                if (walker->ai_family == family) { /* AF_INET6 requested, done */
                    if (walker->ai_addrlen == sizeof(struct sockaddr_in6)) {
                        struct sockaddr_in6 *addr = (struct sockaddr_in6 *)walker->ai_addr;
                        to->ip6.in6_addr = addr->sin6_addr;
                        result = TOX_ADDR_RESOLVE_INET6;
                        done = 1;
                    }
                } else if (!(result & TOX_ADDR_RESOLVE_INET6)) { /* AF_UNSPEC requested, store away */
                    if (walker->ai_addrlen == sizeof(struct sockaddr_in6)) {
                        struct sockaddr_in6 *addr = (struct sockaddr_in6 *)walker->ai_addr;
                        ip6.ip6.in6_addr = addr->sin6_addr;
                        result |= TOX_ADDR_RESOLVE_INET6;
                    }
                }

                break; /* switch */
        }
    }

    if (family == AF_UNSPEC) {
        if (result & TOX_ADDR_RESOLVE_INET6) {
            ip_copy(to, &ip6);

            if ((result & TOX_ADDR_RESOLVE_INET) && (extra != NULL)) {
                ip_copy(extra, &ip4);
            }
        } else if (result & TOX_ADDR_RESOLVE_INET) {
            ip_copy(to, &ip4);
        } else {
            result = 0;
        }
    }

    freeaddrinfo(server);
    return result;
}

/*
 * addr_resolve_or_parse_ip
 *  resolves string into an IP address
 *
 *  address: a hostname (or something parseable to an IP address)
 *  to: to.family MUST be initialized, either set to a specific IP version
 *     (AF_INET/AF_INET6) or to the unspecified AF_UNSPEC (= 0), if both
 *     IP versions are acceptable
 *  extra can be NULL and is only set in special circumstances, see returns
 *
 *  returns in *tro a matching address (IPv6 or IPv4)
 *  returns in *extra, if not NULL, an IPv4 address, if to->family was AF_UNSPEC
 *  returns 1 on success
 *  returns 0 on failure
 */
int addr_resolve_or_parse_ip(const char *address, IP *to, IP *extra)
{
    if (!addr_resolve(address, to, extra)) {
        if (!addr_parse_ip(address, to)) {
            return 0;
        }
    }

    return 1;
}