This file is indexed.

/usr/share/perl5/IO/Socket/IP.pm is in libio-socket-ip-perl 0.32-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   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
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
#  You may distribute under the terms of either the GNU General Public License
#  or the Artistic License (the same terms as Perl itself)
#
#  (C) Paul Evans, 2010-2014 -- leonerd@leonerd.org.uk

package IO::Socket::IP;
# $VERSION needs to be set before  use base 'IO::Socket'
#  - https://rt.cpan.org/Ticket/Display.html?id=92107
BEGIN {
   $VERSION = '0.32';
}

use strict;
use warnings;
use base qw( IO::Socket );

use Carp;

use Socket 1.97 qw(
   getaddrinfo getnameinfo
   sockaddr_family
   AF_INET
   AI_PASSIVE
   IPPROTO_TCP IPPROTO_UDP
   IPPROTO_IPV6 IPV6_V6ONLY
   NI_DGRAM NI_NUMERICHOST NI_NUMERICSERV NIx_NOHOST NIx_NOSERV
   SO_REUSEADDR SO_REUSEPORT SO_BROADCAST SO_ERROR
   SOCK_DGRAM SOCK_STREAM
   SOL_SOCKET
);
my $AF_INET6 = eval { Socket::AF_INET6() }; # may not be defined
my $AI_ADDRCONFIG = eval { Socket::AI_ADDRCONFIG() } || 0;
use POSIX qw( dup2 );
use Errno qw( EINVAL EINPROGRESS EISCONN ETIMEDOUT EWOULDBLOCK );

use constant HAVE_MSWIN32 => ( $^O eq "MSWin32" );

# At least one OS (Android) is known not to have getprotobyname()
use constant HAVE_GETPROTOBYNAME => defined eval { getprotobyname( "tcp" ) };

my $IPv6_re = do {
   # translation of RFC 3986 3.2.2 ABNF to re
   my $IPv4address = do {
      my $dec_octet = q<(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])>;
      qq<$dec_octet(?: \\. $dec_octet){3}>;
   };
   my $IPv6address = do {
      my $h16  = qq<[0-9A-Fa-f]{1,4}>;
      my $ls32 = qq<(?: $h16 : $h16 | $IPv4address)>;
      qq<(?:
                                            (?: $h16 : ){6} $ls32
         |                               :: (?: $h16 : ){5} $ls32
         | (?:                   $h16 )? :: (?: $h16 : ){4} $ls32
         | (?: (?: $h16 : ){0,1} $h16 )? :: (?: $h16 : ){3} $ls32
         | (?: (?: $h16 : ){0,2} $h16 )? :: (?: $h16 : ){2} $ls32
         | (?: (?: $h16 : ){0,3} $h16 )? ::     $h16 :      $ls32
         | (?: (?: $h16 : ){0,4} $h16 )? ::                 $ls32
         | (?: (?: $h16 : ){0,5} $h16 )? ::                 $h16
         | (?: (?: $h16 : ){0,6} $h16 )? ::
      )>
   };
   qr<$IPv6address>xo;
};

=head1 NAME

C<IO::Socket::IP> - Family-neutral IP socket supporting both IPv4 and IPv6

=head1 SYNOPSIS

 use IO::Socket::IP;

 my $sock = IO::Socket::IP->new(
    PeerHost => "www.google.com",
    PeerPort => "http",
    Type     => SOCK_STREAM,
 ) or die "Cannot construct socket - $@";

 my $familyname = ( $sock->sockdomain == PF_INET6 ) ? "IPv6" :
                  ( $sock->sockdomain == PF_INET  ) ? "IPv4" :
                                                      "unknown";

 printf "Connected to google via %s\n", $familyname;

=head1 DESCRIPTION

This module provides a protocol-independent way to use IPv4 and IPv6 sockets,
intended as a replacement for L<IO::Socket::INET>. Most constructor arguments
and methods are provided in a backward-compatible way. For a list of known
differences, see the C<IO::Socket::INET> INCOMPATIBILITES section below.

It uses the C<getaddrinfo(3)> function to convert hostnames and service names
or port numbers into sets of possible addresses to connect to or listen on.
This allows it to work for IPv6 where the system supports it, while still
falling back to IPv4-only on systems which don't.

=head1 REPLACING C<IO::Socket> DEFAULT BEHAVIOUR

By placing C<-register> in the import list, L<IO::Socket> uses
C<IO::Socket::IP> rather than C<IO::Socket::INET> as the class that handles
C<PF_INET>.  C<IO::Socket> will also use C<IO::Socket::IP> rather than
C<IO::Socket::INET6> to handle C<PF_INET6>, provided that the C<AF_INET6>
constant is available.

Changing C<IO::Socket>'s default behaviour means that calling the
C<IO::Socket> constructor with either C<PF_INET> or C<PF_INET6> as the
C<Domain> parameter will yield an C<IO::Socket::IP> object.

 use IO::Socket::IP -register;

 my $sock = IO::Socket->new(
    Domain    => PF_INET6,
    LocalHost => "::1",
    Listen    => 1,
 ) or die "Cannot create socket - $@\n";

 print "Created a socket of type " . ref($sock) . "\n";

Note that C<-register> is a global setting that applies to the entire program;
it cannot be applied only for certain callers, removed, or limited by lexical
scope.

=cut

sub import
{
   my $pkg = shift;
   my @symbols;

   foreach ( @_ ) {
      if( $_ eq "-register" ) {
         IO::Socket::IP::_ForINET->register_domain( AF_INET );
         IO::Socket::IP::_ForINET6->register_domain( $AF_INET6 ) if defined $AF_INET6;
      }
      else {
         push @symbols, $_;
      }
   }

   @_ = ( $pkg, @symbols );
   goto &IO::Socket::import;
}

# Convenient capability test function
{
   my $can_disable_v6only;
   sub CAN_DISABLE_V6ONLY
   {
      return $can_disable_v6only if defined $can_disable_v6only;

      socket my $testsock, Socket::PF_INET6(), SOCK_STREAM, 0 or
         die "Cannot socket(PF_INET6) - $!";

      if( setsockopt $testsock, IPPROTO_IPV6, IPV6_V6ONLY, 0 ) {
         return $can_disable_v6only = 1;
      }
      elsif( $! == EINVAL ) {
         return $can_disable_v6only = 0;
      }
      else {
         die "Cannot setsockopt() - $!";
      }
   }
}

=head1 CONSTRUCTORS

=cut

=head2 $sock = IO::Socket::IP->new( %args )

Creates a new C<IO::Socket::IP> object, containing a newly created socket
handle according to the named arguments passed. The recognised arguments are:

=over 8

=item PeerHost => STRING

=item PeerService => STRING

Hostname and service name for the peer to C<connect()> to. The service name
may be given as a port number, as a decimal string.

=item PeerAddr => STRING

=item PeerPort => STRING

For symmetry with the accessor methods and compatibility with
C<IO::Socket::INET>, these are accepted as synonyms for C<PeerHost> and
C<PeerService> respectively.

=item PeerAddrInfo => ARRAY

Alternate form of specifying the peer to C<connect()> to. This should be an
array of the form returned by C<Socket::getaddrinfo>.

This parameter takes precedence over the C<Peer*>, C<Family>, C<Type> and
C<Proto> arguments.

=item LocalHost => STRING

=item LocalService => STRING

Hostname and service name for the local address to C<bind()> to.

=item LocalAddr => STRING

=item LocalPort => STRING

For symmetry with the accessor methods and compatibility with
C<IO::Socket::INET>, these are accepted as synonyms for C<LocalHost> and
C<LocalService> respectively.

=item LocalAddrInfo => ARRAY

Alternate form of specifying the local address to C<bind()> to. This should be
an array of the form returned by C<Socket::getaddrinfo>.

This parameter takes precedence over the C<Local*>, C<Family>, C<Type> and
C<Proto> arguments.

=item Family => INT

The address family to pass to C<getaddrinfo> (e.g. C<AF_INET>, C<AF_INET6>).
Normally this will be left undefined, and C<getaddrinfo> will search using any
address family supported by the system.

=item Type => INT

The socket type to pass to C<getaddrinfo> (e.g. C<SOCK_STREAM>,
C<SOCK_DGRAM>). Normally defined by the caller; if left undefined
C<getaddrinfo> may attempt to infer the type from the service name.

=item Proto => STRING or INT

The IP protocol to use for the socket (e.g. C<'tcp'>, C<IPPROTO_TCP>,
C<'udp'>,C<IPPROTO_UDP>). Normally this will be left undefined, and either
C<getaddrinfo> or the kernel will choose an appropriate value. May be given
either in string name or numeric form.

=item GetAddrInfoFlags => INT

More flags to pass to the C<getaddrinfo()> function. If not supplied, a
default of C<AI_ADDRCONFIG> will be used.

These flags will be combined with C<AI_PASSIVE> if the C<Listen> argument is
given. For more information see the documentation about C<getaddrinfo()> in
the L<Socket> module.

=item Listen => INT

If defined, puts the socket into listening mode where new connections can be
accepted using the C<accept> method. The value given is used as the
C<listen(2)> queue size.

=item ReuseAddr => BOOL

If true, set the C<SO_REUSEADDR> sockopt

=item ReusePort => BOOL

If true, set the C<SO_REUSEPORT> sockopt (not all OSes implement this sockopt)

=item Broadcast => BOOL

If true, set the C<SO_BROADCAST> sockopt

=item V6Only => BOOL

If defined, set the C<IPV6_V6ONLY> sockopt when creating C<PF_INET6> sockets
to the given value. If true, a listening-mode socket will only listen on the
C<AF_INET6> addresses; if false it will also accept connections from
C<AF_INET> addresses.

If not defined, the socket option will not be changed, and default value set
by the operating system will apply. For repeatable behaviour across platforms
it is recommended this value always be defined for listening-mode sockets.

Note that not all platforms support disabling this option. Some, at least
OpenBSD and MirBSD, will fail with C<EINVAL> if you attempt to disable it.
To determine whether it is possible to disable, you may use the class method

 if( IO::Socket::IP->CAN_DISABLE_V6ONLY ) {
    ...
 }
 else {
    ...
 }

If your platform does not support disabling this option but you still want to
listen for both C<AF_INET> and C<AF_INET6> connections you will have to create
two listening sockets, one bound to each protocol.

=item MultiHomed

This C<IO::Socket::INET>-style argument is ignored, except if it is defined
but false. See the C<IO::Socket::INET> INCOMPATIBILITES section below.

However, the behaviour it enables is always performed by C<IO::Socket::IP>.

=item Blocking => BOOL

If defined but false, the socket will be set to non-blocking mode. Otherwise
it will default to blocking mode. See the NON-BLOCKING section below for more
detail.

=item Timeout => NUM

If defined, gives a maximum time in seconds to block per C<connect()> call
when in blocking mode. If missing, no timeout is applied other than that
provided by the underlying operating system. When in non-blocking mode this
parameter is ignored.

Note that if the hostname resolves to multiple address candidates, the same
timeout will apply to each connection attempt individually, rather than to the
operation as a whole. Further note that the timeout does not apply to the
initial hostname resolve operation, if connecting by hostname.

This behviour is copied inspired by C<IO::Socket::INET>; for more fine grained
control over connection timeouts, consider performing a nonblocking connect
directly.

=back

If neither C<Type> nor C<Proto> hints are provided, a default of
C<SOCK_STREAM> and C<IPPROTO_TCP> respectively will be set, to maintain
compatibility with C<IO::Socket::INET>. Other named arguments that are not
recognised are ignored.

If neither C<Family> nor any hosts or addresses are passed, nor any
C<*AddrInfo>, then the constructor has no information on which to decide a
socket family to create. In this case, it performs a C<getaddinfo> call with
the C<AI_ADDRCONFIG> flag, no host name, and a service name of C<"0">, and
uses the family of the first returned result.

If the constructor fails, it will set C<$@> to an appropriate error message;
this may be from C<$!> or it may be some other string; not every failure
necessarily has an associated C<errno> value.

=head2 $sock = IO::Socket::IP->new( $peeraddr )

As a special case, if the constructor is passed a single argument (as
opposed to an even-sized list of key/value pairs), it is taken to be the value
of the C<PeerAddr> parameter. This is parsed in the same way, according to the
behaviour given in the C<PeerHost> AND C<LocalHost> PARSING section below.

=cut

sub new
{
   my $class = shift;
   my %arg = (@_ == 1) ? (PeerHost => $_[0]) : @_;
   return $class->SUPER::new(%arg);
}

# IO::Socket may call this one; neaten up the arguments from IO::Socket::INET
# before calling our real _configure method
sub configure
{
   my $self = shift;
   my ( $arg ) = @_;

   $arg->{PeerHost} = delete $arg->{PeerAddr}
      if exists $arg->{PeerAddr} && !exists $arg->{PeerHost};

   $arg->{PeerService} = delete $arg->{PeerPort}
      if exists $arg->{PeerPort} && !exists $arg->{PeerService};

   $arg->{LocalHost} = delete $arg->{LocalAddr}
      if exists $arg->{LocalAddr} && !exists $arg->{LocalHost};

   $arg->{LocalService} = delete $arg->{LocalPort}
      if exists $arg->{LocalPort} && !exists $arg->{LocalService};

   for my $type (qw(Peer Local)) {
      my $host    = $type . 'Host';
      my $service = $type . 'Service';

      if( defined $arg->{$host} ) {
         ( $arg->{$host}, my $s ) = $self->split_addr( $arg->{$host} );
         # IO::Socket::INET compat - *Host parsed port always takes precedence
         $arg->{$service} = $s if defined $s;
      }
   }

   $self->_io_socket_ip__configure( $arg );
}

# Avoid simply calling it _configure, as some subclasses of IO::Socket::INET on CPAN already take that
sub _io_socket_ip__configure
{
   my $self = shift;
   my ( $arg ) = @_;

   my %hints;
   my @localinfos;
   my @peerinfos;

   if( defined $arg->{GetAddrInfoFlags} ) {
      $hints{flags} = $arg->{GetAddrInfoFlags};
   }
   else {
      $hints{flags} = $AI_ADDRCONFIG;
   }

   if( defined( my $family = $arg->{Family} ) ) {
      $hints{family} = $family;
   }

   if( defined( my $type = $arg->{Type} ) ) {
      $hints{socktype} = $type;
   }

   if( defined( my $proto = $arg->{Proto} ) ) {
      unless( $proto =~ m/^\d+$/ ) {
         my $protonum = HAVE_GETPROTOBYNAME
            ? getprotobyname( $proto )
            : eval { Socket->${\"IPPROTO_\U$proto"}() };
         defined $protonum or croak "Unrecognised protocol $proto";
         $proto = $protonum;
      }

      $hints{protocol} = $proto;
   }

   # To maintain compatibility with IO::Socket::INET, imply a default of
   # SOCK_STREAM + IPPROTO_TCP if neither hint is given
   if( !defined $hints{socktype} and !defined $hints{protocol} ) {
      $hints{socktype} = SOCK_STREAM;
      $hints{protocol} = IPPROTO_TCP;
   }

   # Some OSes (NetBSD) don't seem to like just a protocol hint without a
   # socktype hint as well. We'll set a couple of common ones
   if( !defined $hints{socktype} and defined $hints{protocol} ) {
      $hints{socktype} = SOCK_STREAM if $hints{protocol} == IPPROTO_TCP;
      $hints{socktype} = SOCK_DGRAM  if $hints{protocol} == IPPROTO_UDP;
   }

   if( my $info = $arg->{LocalAddrInfo} ) {
      ref $info eq "ARRAY" or croak "Expected 'LocalAddrInfo' to be an ARRAY ref";
      @localinfos = @$info;
   }
   elsif( defined $arg->{LocalHost} or defined $arg->{LocalService} ) {
      # Either may be undef
      my $host = $arg->{LocalHost};
      my $service = $arg->{LocalService};

      local $1; # Placate a taint-related bug; [perl #67962]
      defined $service and $service =~ s/\((\d+)\)$// and
         my $fallback_port = $1;

      my %localhints = %hints;
      $localhints{flags} |= AI_PASSIVE;
      ( my $err, @localinfos ) = getaddrinfo( $host, $service, \%localhints );

      if( $err and defined $fallback_port ) {
         ( $err, @localinfos ) = getaddrinfo( $host, $fallback_port, \%localhints );
      }

      if( $err ) {
         $@ = "$err";
         $! = EINVAL;
         return;
      }
   }

   if( my $info = $arg->{PeerAddrInfo} ) {
      ref $info eq "ARRAY" or croak "Expected 'PeerAddrInfo' to be an ARRAY ref";
      @peerinfos = @$info;
   }
   elsif( defined $arg->{PeerHost} or defined $arg->{PeerService} ) {
      defined( my $host = $arg->{PeerHost} ) or
         croak "Expected 'PeerHost'";
      defined( my $service = $arg->{PeerService} ) or
         croak "Expected 'PeerService'";

      local $1; # Placate a taint-related bug; [perl #67962]
      defined $service and $service =~ s/\((\d+)\)$// and
         my $fallback_port = $1;

      ( my $err, @peerinfos ) = getaddrinfo( $host, $service, \%hints );

      if( $err and defined $fallback_port ) {
         ( $err, @peerinfos ) = getaddrinfo( $host, $fallback_port, \%hints );
      }

      if( $err ) {
         $@ = "$err";
         $! = EINVAL;
         return;
      }
   }

   my @sockopts_enabled;
   push @sockopts_enabled, SO_REUSEADDR if $arg->{ReuseAddr};
   push @sockopts_enabled, SO_REUSEPORT if $arg->{ReusePort};
   push @sockopts_enabled, SO_BROADCAST if $arg->{Broadcast};

   my $listenqueue = $arg->{Listen};

   croak "Cannot Listen with a PeerHost" if defined $listenqueue and @peerinfos;

   my $blocking = $arg->{Blocking};
   defined $blocking or $blocking = 1;

   my $v6only = $arg->{V6Only};

   # IO::Socket::INET defines this key. IO::Socket::IP always implements the
   # behaviour it requests, so we can ignore it, unless the caller is for some
   # reason asking to disable it.
   if( defined $arg->{MultiHomed} and !$arg->{MultiHomed} ) {
      croak "Cannot disable the MultiHomed parameter";
   }

   my @infos;
   foreach my $local ( @localinfos ? @localinfos : {} ) {
      foreach my $peer ( @peerinfos ? @peerinfos : {} ) {
         next if defined $local->{family}   and defined $peer->{family}   and
            $local->{family} != $peer->{family};
         next if defined $local->{socktype} and defined $peer->{socktype} and
            $local->{socktype} != $peer->{socktype};
         next if defined $local->{protocol} and defined $peer->{protocol} and
            $local->{protocol} != $peer->{protocol};

         my $family   = $local->{family}   || $peer->{family}   or next;
         my $socktype = $local->{socktype} || $peer->{socktype} or next;
         my $protocol = $local->{protocol} || $peer->{protocol} || 0;

         push @infos, {
            family    => $family,
            socktype  => $socktype,
            protocol  => $protocol,
            localaddr => $local->{addr},
            peeraddr  => $peer->{addr},
         };
      }
   }

   if( !@infos ) {
      # If there was a Family hint then create a plain unbound, unconnected socket
      if( defined $hints{family} ) {
         @infos = ( {
            family   => $hints{family},
            socktype => $hints{socktype},
            protocol => $hints{protocol},
         } );
      }
      # If there wasn't, use getaddrinfo()'s AI_ADDRCONFIG side-effect to guess a
      # suitable family first.
      else {
         ( my $err, @infos ) = getaddrinfo( "", "0", \%hints );
         if( $err ) {
            $@ = "$err";
            $! = EINVAL;
            return;
         }

         # We'll take all the @infos anyway, because some OSes (HPUX) are known to
         # ignore the AI_ADDRCONFIG hint and return AF_INET6 even if they don't
         # support them
      }
   }

   # In the nonblocking case, caller will be calling ->setup multiple times.
   # Store configuration in the object for the ->setup method
   # Yes, these are messy. Sorry, I can't help that...

   ${*$self}{io_socket_ip_infos} = \@infos;

   ${*$self}{io_socket_ip_idx} = -1;

   ${*$self}{io_socket_ip_sockopts} = \@sockopts_enabled;
   ${*$self}{io_socket_ip_v6only} = $v6only;
   ${*$self}{io_socket_ip_listenqueue} = $listenqueue;
   ${*$self}{io_socket_ip_blocking} = $blocking;

   ${*$self}{io_socket_ip_errors} = [ undef, undef, undef ];

   # ->setup is allowed to return false in nonblocking mode
   $self->setup or !$blocking or return undef;

   return $self;
}

sub setup
{
   my $self = shift;

   while(1) {
      ${*$self}{io_socket_ip_idx}++;
      last if ${*$self}{io_socket_ip_idx} >= @{ ${*$self}{io_socket_ip_infos} };

      my $info = ${*$self}{io_socket_ip_infos}->[${*$self}{io_socket_ip_idx}];

      $self->socket( @{$info}{qw( family socktype protocol )} ) or
         ( ${*$self}{io_socket_ip_errors}[2] = $!, next );

      $self->blocking( 0 ) unless ${*$self}{io_socket_ip_blocking};

      foreach my $sockopt ( @{ ${*$self}{io_socket_ip_sockopts} } ) {
         $self->setsockopt( SOL_SOCKET, $sockopt, pack "i", 1 ) or ( $@ = "$!", return undef );
      }

      if( defined ${*$self}{io_socket_ip_v6only} and defined $AF_INET6 and $info->{family} == $AF_INET6 ) {
         my $v6only = ${*$self}{io_socket_ip_v6only};
         $self->setsockopt( IPPROTO_IPV6, IPV6_V6ONLY, pack "i", $v6only ) or ( $@ = "$!", return undef );
      }

      if( defined( my $addr = $info->{localaddr} ) ) {
         $self->bind( $addr ) or
            ( ${*$self}{io_socket_ip_errors}[1] = $!, next );
      }

      if( defined( my $listenqueue = ${*$self}{io_socket_ip_listenqueue} ) ) {
         $self->listen( $listenqueue ) or ( $@ = "$!", return undef );
      }

      if( defined( my $addr = $info->{peeraddr} ) ) {
         if( $self->connect( $addr ) ) {
            $! = 0;
            return 1;
         }

         if( $! == EINPROGRESS or HAVE_MSWIN32 && $! == Errno::EWOULDBLOCK() ) {
            ${*$self}{io_socket_ip_connect_in_progress} = 1;
            return 0;
         }

         # If connect failed but we have no system error there must be an error
         # at the application layer, like a bad certificate with
         # IO::Socket::SSL.
         # In this case don't continue IP based multi-homing because the problem
         # cannot be solved at the IP layer.
         return 0 if ! $!;

         ${*$self}{io_socket_ip_errors}[0] = $!;
         next;
      }

      return 1;
   }

   # Pick the most appropriate error, stringified
   $! = ( grep defined, @{ ${*$self}{io_socket_ip_errors}} )[0];
   $@ = "$!";
   return undef;
}

sub connect
{
   my $self = shift;

   # It seems that IO::Socket hides EINPROGRESS errors, making them look like
   # a success. This is annoying here.
   # Instead of putting up with its frankly-irritating intentional breakage of
   # useful APIs I'm just going to end-run around it and call CORE::connect()
   # directly

   if( @_ ) {
      my ( $addr ) = @_;

      # Annoyingly IO::Socket's connect() is where the timeout logic is
      # implemented, so we'll have to reinvent it here
      my $timeout = ${*$self}{'io_socket_timeout'};

      return CORE::connect( $self, $addr ) unless defined $timeout;

      my $was_blocking = $self->blocking( 0 );

      my $err = defined CORE::connect( $self, $addr ) ? 0 : $!+0;

      if( !$err ) {
         # All happy
         return 1;
      }
      elsif( not( $err == EINPROGRESS or $err == EWOULDBLOCK ) ) {
         # Failed for some other reason
         return undef;
      }
      elsif( !$was_blocking ) {
         # We shouldn't block anyway
         return undef;
      }

      my $vec = ''; vec( $vec, $self->fileno, 1 ) = 1;
      if( !select( $vec, $vec, $vec, $timeout ) ) {
         $! = ETIMEDOUT;
         return undef;
      }

      # Hoist the error by connect()ing a second time
      $err = defined CORE::connect( $self, $addr ) ? 0 : $!+0;
      $err = 0 if $err == EISCONN; # Some OSes give EISCONN

      $self->blocking( $was_blocking );

      $! = $err, return undef if $err;
      return 1;
   }

   return 1 if !${*$self}{io_socket_ip_connect_in_progress};

   # See if a connect attempt has just failed with an error
   if( my $errno = $self->getsockopt( SOL_SOCKET, SO_ERROR ) ) {
      delete ${*$self}{io_socket_ip_connect_in_progress};
      ${*$self}{io_socket_ip_errors}[0] = $! = $errno;
      return $self->setup;
   }

   # No error, so either connect is still in progress, or has completed
   # successfully. We can tell by trying to connect() again; either it will
   # succeed or we'll get EISCONN (connected successfully), or EALREADY
   # (still in progress). This even works on MSWin32.
   my $addr = ${*$self}{io_socket_ip_infos}[${*$self}{io_socket_ip_idx}]{peeraddr};

   if( CORE::connect( $self, $addr ) or $! == EISCONN ) {
      delete ${*$self}{io_socket_ip_connect_in_progress};
      $! = 0;
      return 1;
   }
   else {
      $! = EINPROGRESS;
      return 0;
   }
}

sub connected
{
   my $self = shift;
   return defined $self->fileno &&
          !${*$self}{io_socket_ip_connect_in_progress} &&
          defined getpeername( $self ); # ->peername caches, we need to detect disconnection
}

=head1 METHODS

As well as the following methods, this class inherits all the methods in
L<IO::Socket> and L<IO::Handle>.

=cut

sub _get_host_service
{
   my $self = shift;
   my ( $addr, $flags, $xflags ) = @_;

   $flags |= NI_DGRAM if $self->socktype == SOCK_DGRAM;

   my ( $err, $host, $service ) = getnameinfo( $addr, $flags, $xflags || 0 );
   croak "getnameinfo - $err" if $err;

   return ( $host, $service );
}

sub _unpack_sockaddr
{
   my ( $addr ) = @_;
   my $family = sockaddr_family $addr;

   if( $family == AF_INET ) {
      return ( Socket::unpack_sockaddr_in( $addr ) )[1];
   }
   elsif( defined $AF_INET6 and $family == $AF_INET6 ) {
      return ( Socket::unpack_sockaddr_in6( $addr ) )[1];
   }
   else {
      croak "Unrecognised address family $family";
   }
}

=head2 ( $host, $service ) = $sock->sockhost_service( $numeric )

Returns the hostname and service name of the local address (that is, the
socket address given by the C<sockname> method).

If C<$numeric> is true, these will be given in numeric form rather than being
resolved into names.

The following four convenience wrappers may be used to obtain one of the two
values returned here. If both host and service names are required, this method
is preferable to the following wrappers, because it will call
C<getnameinfo(3)> only once.

=cut

sub sockhost_service
{
   my $self = shift;
   my ( $numeric ) = @_;

   $self->_get_host_service( $self->sockname, $numeric ? NI_NUMERICHOST|NI_NUMERICSERV : 0 );
}

=head2 $addr = $sock->sockhost

Return the numeric form of the local address as a textual representation

=head2 $port = $sock->sockport

Return the numeric form of the local port number

=head2 $host = $sock->sockhostname

Return the resolved name of the local address

=head2 $service = $sock->sockservice

Return the resolved name of the local port number

=cut

sub sockhost { my $self = shift; ( $self->_get_host_service( $self->sockname, NI_NUMERICHOST, NIx_NOSERV ) )[0] }
sub sockport { my $self = shift; ( $self->_get_host_service( $self->sockname, NI_NUMERICSERV, NIx_NOHOST ) )[1] }

sub sockhostname { my $self = shift; ( $self->_get_host_service( $self->sockname, 0, NIx_NOSERV ) )[0] }
sub sockservice  { my $self = shift; ( $self->_get_host_service( $self->sockname, 0, NIx_NOHOST ) )[1] }

=head2 $addr = $sock->sockaddr

Return the local address as a binary octet string

=cut

sub sockaddr { my $self = shift; _unpack_sockaddr $self->sockname }

=head2 ( $host, $service ) = $sock->peerhost_service( $numeric )

Returns the hostname and service name of the peer address (that is, the
socket address given by the C<peername> method), similar to the
C<sockhost_service> method.

The following four convenience wrappers may be used to obtain one of the two
values returned here. If both host and service names are required, this method
is preferable to the following wrappers, because it will call
C<getnameinfo(3)> only once.

=cut

sub peerhost_service
{
   my $self = shift;
   my ( $numeric ) = @_;

   $self->_get_host_service( $self->peername, $numeric ? NI_NUMERICHOST|NI_NUMERICSERV : 0 );
}

=head2 $addr = $sock->peerhost

Return the numeric form of the peer address as a textual representation

=head2 $port = $sock->peerport

Return the numeric form of the peer port number

=head2 $host = $sock->peerhostname

Return the resolved name of the peer address

=head2 $service = $sock->peerservice

Return the resolved name of the peer port number

=cut

sub peerhost { my $self = shift; ( $self->_get_host_service( $self->peername, NI_NUMERICHOST, NIx_NOSERV ) )[0] }
sub peerport { my $self = shift; ( $self->_get_host_service( $self->peername, NI_NUMERICSERV, NIx_NOHOST ) )[1] }

sub peerhostname { my $self = shift; ( $self->_get_host_service( $self->peername, 0, NIx_NOSERV ) )[0] }
sub peerservice  { my $self = shift; ( $self->_get_host_service( $self->peername, 0, NIx_NOHOST ) )[1] }

=head2 $addr = $peer->peeraddr

Return the peer address as a binary octet string

=cut

sub peeraddr { my $self = shift; _unpack_sockaddr $self->peername }

# This unbelievably dodgy hack works around the bug that IO::Socket doesn't do
# it
#    https://rt.cpan.org/Ticket/Display.html?id=61577
sub accept
{
   my $self = shift;
   my ( $new, $peer ) = $self->SUPER::accept( @_ ) or return;

   ${*$new}{$_} = ${*$self}{$_} for qw( io_socket_domain io_socket_type io_socket_proto );

   return wantarray ? ( $new, $peer )
                    : $new;
}

# This second unbelievably dodgy hack guarantees that $self->fileno doesn't
# change, which is useful during nonblocking connect
sub socket
{
   my $self = shift;
   return $self->SUPER::socket(@_) if not defined $self->fileno;

   # I hate core prototypes sometimes...
   CORE::socket( my $tmph, $_[0], $_[1], $_[2] ) or return undef;

   dup2( $tmph->fileno, $self->fileno ) or die "Unable to dup2 $tmph onto $self - $!";
}

# Versions of IO::Socket before 1.35 may leave socktype undef if from, say, an
#   ->fdopen call. In this case we'll apply a fix
BEGIN {
   if( $IO::Socket::VERSION < 1.35 ) {
      *socktype = sub {
         my $self = shift;
         my $type = $self->SUPER::socktype;
         if( !defined $type ) {
            $type = $self->sockopt( Socket::SO_TYPE() );
         }
         return $type;
      };
   }
}

=head2 $inet = $sock->as_inet

Returns a new L<IO::Socket::INET> instance wrapping the same filehandle. This
may be useful in cases where it is required, for backward-compatibility, to
have a real object of C<IO::Socket::INET> type instead of C<IO::Socket::IP>.
The new object will wrap the same underlying socket filehandle as the
original, so care should be taken not to continue to use both objects
concurrently. Ideally the original C<$sock> should be discarded after this
method is called.

This method checks that the socket domain is C<PF_INET> and will throw an
exception if it isn't.

=cut

sub as_inet
{
   my $self = shift;
   croak "Cannot downgrade a non-PF_INET socket to IO::Socket::INET" unless $self->sockdomain == AF_INET;
   return IO::Socket::INET->new_from_fd( $self->fileno, "r+" );
}

=head1 NON-BLOCKING

If the constructor is passed a defined but false value for the C<Blocking>
argument then the socket is put into non-blocking mode. When in non-blocking
mode, the socket will not be set up by the time the constructor returns,
because the underlying C<connect(2)> syscall would otherwise have to block.

The non-blocking behaviour is an extension of the C<IO::Socket::INET> API,
unique to C<IO::Socket::IP>, because the former does not support multi-homed
non-blocking connect.

When using non-blocking mode, the caller must repeatedly check for
writeability on the filehandle (for instance using C<select> or C<IO::Poll>).
Each time the filehandle is ready to write, the C<connect> method must be
called, with no arguments. Note that some operating systems, most notably
C<MSWin32> do not report a C<connect()> failure using write-ready; so you must
also C<select()> for exceptional status.

While C<connect> returns false, the value of C<$!> indicates whether it should
be tried again (by being set to the value C<EINPROGRESS>, or C<EWOULDBLOCK> on
MSWin32), or whether a permanent error has occurred (e.g. C<ECONNREFUSED>).

Once the socket has been connected to the peer, C<connect> will return true
and the socket will now be ready to use.

Note that calls to the platform's underlying C<getaddrinfo(3)> function may
block. If C<IO::Socket::IP> has to perform this lookup, the constructor will
block even when in non-blocking mode.

To avoid this blocking behaviour, the caller should pass in the result of such
a lookup using the C<PeerAddrInfo> or C<LocalAddrInfo> arguments. This can be
achieved by using L<Net::LibAsyncNS>, or the C<getaddrinfo(3)> function can be
called in a child process.

 use IO::Socket::IP;
 use Errno qw( EINPROGRESS EWOULDBLOCK );

 my @peeraddrinfo = ... # Caller must obtain the getaddinfo result here

 my $socket = IO::Socket::IP->new(
    PeerAddrInfo => \@peeraddrinfo,
    Blocking     => 0,
 ) or die "Cannot construct socket - $@";

 while( !$socket->connect and ( $! == EINPROGRESS || $! == EWOULDBLOCK ) ) {
    my $wvec = '';
    vec( $wvec, fileno $socket, 1 ) = 1;
    my $evec = '';
    vec( $evec, fileno $socket, 1 ) = 1;

    select( undef, $wvec, $evec, undef ) or die "Cannot select - $!";
 }

 die "Cannot connect - $!" if $!;

 ...

The example above uses C<select()>, but any similar mechanism should work
analogously. C<IO::Socket::IP> takes care when creating new socket filehandles
to preserve the actual file descriptor number, so such techniques as C<poll>
or C<epoll> should be transparent to its reallocation of a different socket
underneath, perhaps in order to switch protocol family between C<PF_INET> and
C<PF_INET6>.

For another example using C<IO::Poll> and C<Net::LibAsyncNS>, see the
F<examples/nonblocking_libasyncns.pl> file in the module distribution.

=cut

=head1 C<PeerHost> AND C<LocalHost> PARSING

To support the C<IO::Socket::INET> API, the host and port information may be
passed in a single string rather than as two separate arguments.

If either C<LocalHost> or C<PeerHost> (or their C<...Addr> synonyms) have any
of the following special forms then special parsing is applied.

The value of the C<...Host> argument will be split to give both the hostname
and port (or service name):

 hostname.example.org:http    # Host name
 192.0.2.1:80                 # IPv4 address
 [2001:db8::1]:80             # IPv6 address

In each case, the port or service name (e.g. C<80>) is passed as the
C<LocalService> or C<PeerService> argument.

Either of C<LocalService> or C<PeerService> (or their C<...Port> synonyms) can
be either a service name, a decimal number, or a string containing both a
service name and number, in a form such as

 http(80)

In this case, the name (C<http>) will be tried first, but if the resolver does
not understand it then the port number (C<80>) will be used instead.

If the C<...Host> argument is in this special form and the corresponding
C<...Service> or C<...Port> argument is also defined, the one parsed from
the C<...Host> argument will take precedence and the other will be ignored.

=head2 ( $host, $port ) = IO::Socket::IP->split_addr( $addr )

Utility method that provides the parsing functionality described above.
Returns a 2-element list, containing either the split hostname and port
description if it could be parsed, or the given address and C<undef> if it was
not recognised.

 IO::Socket::IP->split_addr( "hostname:http" )
                              # ( "hostname",  "http" )

 IO::Socket::IP->split_addr( "192.0.2.1:80" )
                              # ( "192.0.2.1", "80"   )

 IO::Socket::IP->split_addr( "[2001:db8::1]:80" )
                              # ( "2001:db8::1", "80" )

 IO::Socket::IP->split_addr( "something.else" )
                              # ( "something.else", undef )

=cut

sub split_addr
{
   shift;
   my ( $addr ) = @_;

   local ( $1, $2 ); # Placate a taint-related bug; [perl #67962]
   if( $addr =~ m/\A\[($IPv6_re)\](?::([^\s:]*))?\z/ or
       $addr =~ m/\A([^\s:]*):([^\s:]*)\z/ ) {
      return ( $1, $2 ) if defined $2 and length $2;
      return ( $1, undef );
   }

   return ( $addr, undef );
}

=head2 $addr = IO::Socket::IP->join_addr( $host, $port )

Utility method that performs the reverse of C<split_addr>, returning a string
formed by joining the specified host address and port number. The host address
will be wrapped in C<[]> brackets if required (because it is a raw IPv6
numeric address).

This can be especially useful when combined with the C<sockhost_service> or
C<peerhost_service> methods.

 say "Connected to ", IO::Socket::IP->join_addr( $sock->peerhost_service );

=cut

sub join_addr
{
   shift;
   my ( $host, $port ) = @_;

   $host = "[$host]" if $host =~ m/:/;

   return join ":", $host, $port if defined $port;
   return $host;
}

# Since IO::Socket->new( Domain => ... ) will delete the Domain parameter
# before calling ->configure, we need to keep track of which it was

package # hide from indexer
   IO::Socket::IP::_ForINET;
use base qw( IO::Socket::IP );

sub configure
{
   # This is evil
   my $self = shift;
   my ( $arg ) = @_;

   bless $self, "IO::Socket::IP";
   $self->configure( { %$arg, Family => Socket::AF_INET() } );
}

package # hide from indexer
   IO::Socket::IP::_ForINET6;
use base qw( IO::Socket::IP );

sub configure
{
   # This is evil
   my $self = shift;
   my ( $arg ) = @_;

   bless $self, "IO::Socket::IP";
   $self->configure( { %$arg, Family => Socket::AF_INET6() } );
}

=head1 C<IO::Socket::INET> INCOMPATIBILITES

=over 4

=item *

The behaviour enabled by C<MultiHomed> is in fact implemented by
C<IO::Socket::IP> as it is required to correctly support searching for a
useable address from the results of the C<getaddrinfo(3)> call. The
constructor will ignore the value of this argument, except if it is defined
but false. An exception is thrown in this case, because that would request it
disable the C<getaddrinfo(3)> search behaviour in the first place.

=item *

C<IO::Socket::IP> implements both the C<Blocking> and C<Timeout> parameters,
but it implements the interaction of both in a different way.

In C<::INET>, supplying a timeout overrides the non-blocking behaviour,
meaning that the C<connect()> operation will still block despite that the
caller asked for a non-blocking socket. This is not explicitly specified in
its documentation, nor does this author believe that is a useful behaviour -
it appears to come from a quirk of implementation.

In C<::IP> therefore, the C<Blocking> parameter takes precedence - if a
non-blocking socket is requested, no operation will block. The C<Timeout>
parameter here simply defines the maximum time that a blocking C<connect()>
call will wait, if it blocks at all.

In order to specifically obtain the "blocking connect then non-blocking send
and receive" behaviour of specifying this combination of options to C<::INET>
when using C<::IP>, perform first a blocking connect, then afterwards turn the
socket into nonblocking mode.

 my $sock = IO::Socket::IP->new(
    PeerHost => $peer,
    Timeout => 20,
 ) or die "Cannot connect - $@";

 $sock->blocking( 0 );

This code will behave identically under both C<IO::Socket::INET> and
C<IO::Socket::IP>.

=back

=cut

=head1 TODO

=over 4

=item *

Investigate whether C<POSIX::dup2> upsets BSD's C<kqueue> watchers, and if so,
consider what possible workarounds might be applied.

=back

=head1 AUTHOR

Paul Evans <leonerd@leonerd.org.uk>

=cut

0x55AA;