[perl #75630] IO::Socket does not provide the IPV6_V6ONLY constant

# New Ticket Created by  michael+perl@stapelberg.de 
# Please include the string:  [perl #75630]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=75630 >



This is a bug report for perl from michael+perl@stapelberg.de,
generated with the help of perlbug 1.39 running under perl 5.10.1.


-----------------------------------------------------------------
When opening an IPv6 socket, one wants to ensure that the IPV6_V6ONLY
socket option is set to 1 to prevent the socket from listening on
IPv4 too and using mapped addresses (regardless of the system default
value in /proc/sys/net/ipv6/bindv6only).

Unfortunately, IO::Socket does not provide this constant. Please add
it.

By the way: It seems that on Windows, you need to take special care
of it -- the constant may not be available. Since I don't use windows,
I cannot tell you anything more about it.

Example code which needs this socket option:
#!/usr/bin/env perl

use strict;
use warnings;
use Socket qw(SOCK_STREAM IPPROTO_IPV6 IPPROTO_TCP TCP_NODELAY);
use Socket::GetAddrInfo qw(:newapi getaddrinfo getnameinfo AI_PASSIVE NI_NUMERICHOST NI_NUMERICSERV);
use IO::Socket;

my %hints = (socktype => SOCK_STREAM, flags => AI_PASSIVE);
my ($err, @res) = getaddrinfo("", "35111", \%hints);
die "Cannot resolve name - $err" if $err;

while (my $ai = shift @res) {
    my $sock = IO::Socket->new();
    $sock->socket($ai->{family}, $ai->{socktype}, $ai->{protocol}) or next;
    if ($ai->{family} == AF_INET6) {
        # 26 is the value of IPV6_V6ONLY on Linux
        setsockopt($sock, IPPROTO_IPV6, 26, 1) or die "setsockopt: $!";
    }
    $sock->bind($ai->{addr}) or die "bind: $!\n";
    $sock->listen(5) or die "listen: $!\n";

    my $flags = NI_NUMERICHOST | NI_NUMERICSERV;
    my ($err, $host, $port) = getnameinfo($sock->sockname, $flags);
    print "Listening on [$host]:$port\n" if !$err;
}

Without the setsockopt, this code will fail if
/proc/sys/net/ipv6/bindv6only is set to 0.
-----------------------------------------------------------------
---
Flags:
    category=library
    severity=medium
    module=IO::Socket
---
Site configuration information for perl 5.10.1:

Configured by Debian Project at Sun Apr 11 20:09:49 UTC 2010.

Summary of my perl5 (revision 5 version 10 subversion 1) configuration:
   
  Platform:
    osname=linux, osvers=2.6.32-3-amd64, archname=x86_64-linux-gnu-thread-multi
    uname='linux madeleine 2.6.32-3-amd64 #1 smp wed feb 24 18:07:42 utc 2010 x86_64 gnulinux '
    config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.10 -Darchlib=/usr/lib/perl/5.10 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.10.1 -Dsitearch=/usr/local/lib/perl/5.10.1 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm -Uusesfio -Uusenm -DDEBUGGING=-g -Doptimize=-O2 -Duseshrplib -Dlibperl=libperl.so.5.10.1 -Dd_dosuid -des'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2 -g',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.4.3', gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib /lib64 /usr/lib64
    libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
    perllibs=-ldl -lm -lpthread -lc -lcrypt
    libc=/lib/libc-2.10.2.so, so=so, useshrplib=true, libperl=libperl.so.5.10.1
    gnulibc_version='2.10.2'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib -fstack-protector'

Locally applied patches:
    DEBPKG:debian/arm_thread_stress_timeout - http://bugs.debian.org/501970 Raise the timeout of ext/threads/shared/t/stress.t to accommodate slower build hosts
    DEBPKG:debian/cpan_config_path - Set location of CPAN::Config to /etc/perl as /usr may not be writable.
    DEBPKG:debian/cpan_definstalldirs - Provide a sensible INSTALLDIRS default for modules installed from CPAN.
    DEBPKG:debian/db_file_ver - http://bugs.debian.org/340047 Remove overly restrictive DB_File version check.
    DEBPKG:debian/doc_info - Replace generic man(1) instructions with Debian-specific information.
    DEBPKG:debian/enc2xs_inc - http://bugs.debian.org/290336 Tweak enc2xs to follow symlinks and ignore missing @INC directories.
    DEBPKG:debian/errno_ver - http://bugs.debian.org/343351 Remove Errno version check due to upgrade problems with long-running processes.
    DEBPKG:debian/extutils_hacks - Various debian-specific ExtUtils changes
    DEBPKG:debian/fakeroot - Postpone LD_LIBRARY_PATH evaluation to the binary targets.
    DEBPKG:debian/instmodsh_doc - Debian policy doesn't install .packlist files for core or vendor.
    DEBPKG:debian/ld_run_path - Remove standard libs from LD_RUN_PATH as per Debian policy.
    DEBPKG:debian/libnet_config_path - Set location of libnet.cfg to /etc/perl/Net as /usr may not be writable.
    DEBPKG:debian/m68k_thread_stress - http://bugs.debian.org/495826 Disable some threads tests on m68k for now due to missing TLS.
    DEBPKG:debian/mod_paths - Tweak @INC ordering for Debian
    DEBPKG:debian/module_build_man_extensions - http://bugs.debian.org/479460 Adjust Module::Build manual page extensions for the Debian Perl policy
    DEBPKG:debian/perl_synopsis - http://bugs.debian.org/278323 Rearrange perl.pod
    DEBPKG:debian/prune_libs - http://bugs.debian.org/128355 Prune the list of libraries wanted to what we actually need.
    DEBPKG:debian/use_gdbm - Explicitly link against -lgdbm_compat in ODBM_File/NDBM_File. 
    DEBPKG:fixes/assorted_docs - http://bugs.debian.org/443733 [384f06a] Math::BigInt::CalcEmu documentation grammar fix
    DEBPKG:fixes/net_smtp_docs - http://bugs.debian.org/100195 [rt.cpan.org #36038] Document the Net::SMTP 'Port' option
    DEBPKG:fixes/processPL - http://bugs.debian.org/357264 [rt.cpan.org #17224] Always use PERLRUNINST when building perl modules.
    DEBPKG:debian/perlivp - http://bugs.debian.org/510895 Make perlivp skip include directories in /usr/local
    DEBPKG:fixes/pod2man-index-backslash - http://bugs.debian.org/521256 Escape backslashes in .IX entries
    DEBPKG:debian/disable-zlib-bundling - Disable zlib bundling in Compress::Raw::Zlib
    DEBPKG:fixes/kfreebsd_cppsymbols - http://bugs.debian.org/533098 [3b910a0] Add gcc predefined macros to $Config{cppsymbols} on GNU/kFreeBSD.
    DEBPKG:debian/cpanplus_definstalldirs - http://bugs.debian.org/533707 Configure CPANPLUS to use the site directories by default.
    DEBPKG:debian/cpanplus_config_path - Save local versions of CPANPLUS::Config::System into /etc/perl.
    DEBPKG:fixes/kfreebsd-filecopy-pipes - http://bugs.debian.org/537555 [16f708c] Fix File::Copy::copy with pipes on GNU/kFreeBSD
    DEBPKG:fixes/anon-tmpfile-dir - http://bugs.debian.org/528544 [perl #66452] Honor TMPDIR when open()ing an anonymous temporary file
    DEBPKG:fixes/abstract-sockets - http://bugs.debian.org/329291 [89904c0] Add support for Abstract namespace sockets.
    DEBPKG:fixes/hurd_cppsymbols - http://bugs.debian.org/544307 [eeb92b7] Add gcc predefined macros to $Config{cppsymbols} on GNU/Hurd.
    DEBPKG:fixes/autodie-flock - http://bugs.debian.org/543731 Allow for flock returning EAGAIN instead of EWOULDBLOCK on linux/parisc
    DEBPKG:fixes/archive-tar-instance-error - http://bugs.debian.org/539355 [rt.cpan.org #48879] Separate Archive::Tar instance error strings from each other
    DEBPKG:fixes/positive-gpos - http://bugs.debian.org/545234 [perl #69056] [c584a96] Fix \\G crash on first match
    DEBPKG:debian/devel-ppport-ia64-optim - http://bugs.debian.org/548943 Work around an ICE on ia64
    DEBPKG:fixes/trie-logic-match - http://bugs.debian.org/552291 [perl #69973] [0abd0d7] Fix a DoS in Unicode processing [CVE-2009-3626]
    DEBPKG:fixes/hppa-thread-eagain - http://bugs.debian.org/554218 make the threads-shared test suite more robust, fixing failures on hppa
    DEBPKG:fixes/crash-on-undefined-destroy - http://bugs.debian.org/564074 [perl #71952] [1f15e67] Fix a NULL pointer dereference when looking for a DESTROY method
    DEBPKG:fixes/tainted-errno - http://bugs.debian.org/574129 [perl #61976] [be1cf43] fix an errno stringification bug in taint mode
    DEBPKG:patchlevel - http://bugs.debian.org/567489 List packaged patches for 5.10.1-12 in patchlevel.h

---
@INC for perl 5.10.1:
    /etc/perl
    /usr/local/lib/perl/5.10.1
    /usr/local/share/perl/5.10.1
    /usr/lib/perl5
    /usr/share/perl5
    /usr/lib/perl/5.10
    /usr/share/perl/5.10
    /usr/local/lib/site_perl
    /usr/local/lib/perl/5.10.0
    /usr/local/share/perl/5.10.0
    .

---
Environment for perl 5.10.1:
    HOME=/home/michael
    LANG (unset)
    LANGUAGE (unset)
    LC_ADDRESS=de_DE.UTF-8
    LC_COLLATE=de_DE.UTF-8
    LC_CTYPE=de_DE.UTF-8
    LC_IDENTIFICATION=de_DE.UTF-8
    LC_MEASUREMENT=de_DE.UTF-8
    LC_MESSAGES=C
    LC_MONETARY=de_DE.UTF-8
    LC_NAME=de_DE.UTF-8
    LC_NUMERIC=de_DE.UTF-8
    LC_PAPER=de_DE.UTF-8
    LC_TELEPHONE=de_DE.UTF-8
    LC_TIME=de_DE.UTF-8
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games:/usr/sbin:/sbin
    PERL_BADLANG (unset)
    SHELL=/bin/zsh

• [perl #75630] IO::Socket does not provide the IPV6_V6ONLY constant by michael+perl @ stapelberg . de
• Re: [perl #75630] IO::Socket does not provide the IPV6_V6ONLYconstant by Paul LeoNerd Evans
• Re: [perl #75630] IO::Socket does not provide the IPV6_V6ONLY constant by Nicholas Clark
• Re: [perl #75630] IO::Socket does not provide the IPV6_V6ONLYconstant by Paul LeoNerd Evans