Data::Validate::IP(3p)

NAME
Data::Validate::IP - IPv4 and IPv6 validation methods

VERSION
version 0.31

SYNOPSIS
  use Data::Validate::IP qw(is_ipv4 is_ipv6);

  my $suspect = '1.2.3.4';
  if (is_ipv4($suspect)) {
      print "Looks like an IPv4 address";
  }
  else {
      print "Not an IPv4 address\n";
  }

  $suspect = '::1234';
  if (is_ipv6($suspect)) {
      print "Looks like an IPv6 address";
  }
  else {
      print "Not an IPv6 address\n";
  }

DESCRIPTION
This module provides a number IP address validation subs that both validate and untaint their input. This includes both basic validation (is_ipv4() and is_ipv6()) and special cases like checking whether an address belongs to a specific network or whether an address is public or private (reserved).

USAGE AND SECURITY RECOMMENDATIONS
It's important to understand that if is_ipv4($ip), is_ipv6($ip), or is_ip($ip) return false, then all other validation functions for that IP address family will also return false. So for example, if is_ipv4($ip) returns false, then is_private_ipv4($ip) and is_public_ipv4($ip) will both also return false.

This means that simply calling is_private_ipv4($ip) by itself is not sufficient if you are dealing with untrusted input. You should always check is_ipv4($ip) as well. This applies as well when using IPv6 functions or generic functions like is_private_ip($ip).

There are security implications to this around certain oddly formed addresses. Notably, an address like "010.0.0.1" is technically valid, but the operating system will treat "010" as an octal number. That means that "010.0.0.1" is equivalent to "8.0.0.1", not "10.0.0.1".

However, this module's is_ipv4($ip) and is_ip($ip) functions will return false for addresses like "010.0.0.1" which have octal components. And of course that means that it also returns false for is_private_ipv4($ip) and is_public_ipv4($ip).

FUNCTIONS
All of the functions below are exported by default.

All functions return an untainted value if the test passes and undef if it fails. In theory, this means that you should always check for a defined status explicitly but in practice there are no valid IP addresses where the string form evaluates to false in Perl.

Note that none of these functions actually attempt to test whether the given IP address is routable from your device; they are purely semantic checks.

  is_ipv4($ip), is_ipv6($ip), is_ip($ip)
These functions simply check whether the address is a valid IPv4 or IPv6 address.

  is_innet_ipv4($ip, $network)
This subroutine checks whether the address belongs to the given IPv4 network. The $network argument can either be a string in CIDR notation like "15.0.15.0/24" or a NetAddr::IP object.

This subroutine used to accept many more forms of network specifications (anything Net::Netmask accepts) but this has been deprecated.

  is_unroutable_ipv4($ip)
This subroutine checks whether the address belongs to any of several special use IPv4 networks - "0.0.0.0/8", "100.64.0.0/10", "192.0.0.0/29", "198.18.0.0/15", "240.0.0.0/4" - as defined by RFC 5735 <http://tools.ietf.org/html/rfc5735>, RFC 6333 <http://tools.ietf.org/html/rfc6333>, and RFC 6958 <http://tools.ietf.org/html/rfc6598>.

Arguably, these should be broken down further but this subroutine will always exist for backwards compatibility.

  is_private_ipv4($ip)
This subroutine checks whether the address belongs to any of the private IPv4 networks - "10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16" - as defined by RFC 5735 <http://tools.ietf.org/html/rfc5735>.

  is_loopback_ipv4($ip)
This subroutine checks whether the address belongs to the IPv4 loopback network - "127.0.0.0/8" - as defined by RFC 5735 <http://tools.ietf.org/html/rfc5735>.

  is_linklocal_ipv4($ip)
This subroutine checks whether the address belongs to the IPv4 link local network - "169.254.0.0/16" - as defined by RFC 5735 <http://tools.ietf.org/html/rfc5735>.

  is_testnet_ipv4($ip)
This subroutine checks whether the address belongs to any of the IPv4 TEST-NET networks for use in documentation and example code - "192.0.2.0/24", "198.51.100.0/24", and "203.0.113.0/24" - as defined by RFC 5735 <http://tools.ietf.org/html/rfc5735>.

  is_anycast_ipv4($ip)
This subroutine checks whether the address belongs to the 6to4 relay anycast network - "192.88.99.0/24" - as defined by RFC 5735 <http://tools.ietf.org/html/rfc5735>.

  is_multicast_ipv4($ip)
This subroutine checks whether the address belongs to the IPv4 multicast network - "224.0.0.0/4" - as defined by RFC 5735 <http://tools.ietf.org/html/rfc5735>.

  is_loopback_ipv6($ip)
This subroutine checks whether the address is the IPv6 loopback address - "::1/128" - as defined by RFC 4291 <http://tools.ietf.org/html/rfc4291>.

  is_ipv4_mapped_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 IPv4-mapped address network - "::ffff:0:0/96" - as defined by RFC 4291 <http://tools.ietf.org/html/rfc4291>.

  is_discard_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 discard prefix network - "100::/64" - as defined by RFC 6666 <http://tools.ietf.org/html/rfc6666>.

  is_special_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 special network - "2001::/23" - as defined by RFC 2928 <http://tools.ietf.org/html/rfc2928>.

  is_teredo_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 TEREDO network - "2001::/32" - as defined by RFC 4380 <http://tools.ietf.org/html/rfc4380>.

Note that this network is a subnet of the larger special network at "2001::/23".

  is_orchid_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 ORCHID network - "2001::/32" - as defined by RFC 4380 <http://tools.ietf.org/html/rfc4380>.

Note that this network is a subnet of the larger special network at "2001::/23".

This network is currently scheduled to be returned to the special pool in March of 2014 unless the IETF extends its use. If that happens this subroutine will continue to exist but will always return false.

  is_documentation_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 documentation network - "2001:DB8::/32" - as defined by RFC 3849 <http://tools.ietf.org/html/rfc3849>.

  is_unspecified_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 unspecified network - "::0/128" - as defined by RFC 4291 <http://tools.ietf.org/html/rfc4291>.. Note that the address in this subnet is neither private nor public.

  is_private_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 private network - "FC00::/7" - as defined by RFC 4193 <http://tools.ietf.org/html/rfc4193>.

  is_linklocal_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 link-local unicast network - "FE80::/10" - as defined by RFC 4291 <http://tools.ietf.org/html/rfc4291>.

  is_multicast_ipv6($ip)
This subroutine checks whether the address belongs to the IPv6 multicast network - "FF00::/8" - as defined by RFC 4291 <http://tools.ietf.org/html/rfc4291>.

  is_public_ipv4($ip), is_public_ipv6($ip), is_public_ip($ip)
These subroutines check whether the given IP address belongs to any of the special case networks defined previously. Note that this is not simply the opposite of checking is_private_ipv4() or is_private_ipv6(). The private networks are a subset of all the special case networks.

  is_linklocal_ip($ip)
This subroutine checks whether the address belongs to the IPv4 or IPv6 link-local unicast network.

  is_loopback_ip($ip)
This subroutine checks whether the address is the IPv4 or IPv6 loopback address.

  is_multicast_ip($ip)
This subroutine checks whether the address belongs to the IPv4 or IPv6 multicast network.

  is_private_ip($ip)
This subroutine checks whether the address belongs to the IPv4 or IPv6 private network.

OBJECT-ORIENTED INTERFACE
This module can also be used as a class. You can call "Data::Validate::IP->new()" to get an object and then call any of the validation subroutines as methods on that object. This is somewhat pointless since the object will never contain any state but this interface is kept for backwards compatibility.

SEE ALSO
IPv4

[RFC 5735] [RFC 1918]

IPv6

[RFC 2460] [RFC 4193] [RFC 4291] [RFC 6434]

ACKNOWLEDGEMENTS
Thanks to Richard Sonnen <sonnen@richardsonnen.com> for writing the Data::Validate module.

Thanks to Matt Dainty <matt@bodgit-n-scarper.com> for adding the is_multicast_ipv4() and is_linklocal_ipv4() code.

BUGS
Please report any bugs or feature requests to "bug-data-validate-ip@rt.cpan.org", or through the web interface at <http://rt.cpan.org>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

Bugs may be submitted at <https://github.com/houseabsolute/Data-Validate-IP/issues>.

SOURCE
The source code repository for Data-Validate-IP can be found at <https://github.com/houseabsolute/Data-Validate-IP>.

AUTHORS

•   Neil Neely <neil@neely.cx>

•   Dave Rolsky <autarch@urth.org>

CONTRIBUTOR
Gregory Oschwald <goschwald@maxmind.com>

COPYRIGHT AND LICENSE
This software is copyright (c) 2022 by Neil Neely.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

The full text of the license can be found in the LICENSE file included with this distribution.