Util(3)

User Contributed Perl Documentation

Util(3)

NAME

NetAddr::IP::Util -- IPv4/6 and 128 bit number utilities

SYNOPSIS

use NetAddr::IP::Util qw(
      inet_aton
      inet_ntoa
      ipv6_aton
      ipv6_ntoa
      ipv6_n2x
      ipv6_n2d
      inet_any2n
      hasbits
      isIPv4
      isNewIPv4
      isAnyIPv4
      inet_n2dx
      inet_n2ad
      inet_pton
      inet_ntop
      inet_4map6
      ipv4to6
      mask4to6
      ipanyto6
      maskanyto6
      ipv6to4
      packzeros
      shiftleft
      addconst
      add128
      sub128
      notcontiguous
      bin2bcd
      bcd2bin
      mode
      AF_INET
      AF_INET6
      naip_gethostbyname
);
use NetAddr::IP::Util qw(:all :inet :ipv4 :ipv6 :math)
:inet   =>    inet_aton, inet_ntoa, ipv6_aton
              ipv6_ntoa, ipv6_n2x, ipv6_n2d, 
              inet_any2n, inet_n2dx, inet_n2ad, 
              inet_pton, inet_ntop, inet_4map6, 
              ipv4to6, mask4to6, ipanyto6, packzeros
              maskanyto6, ipv6to4, naip_gethostbyname
:ipv4   =>    inet_aton, inet_ntoa
:ipv6   =>    ipv6_aton, ipv6_ntoa, ipv6_n2x, 
              ipv6_n2d, inet_any2n, inet_n2dx, 
              inet_n2ad, inet_pton, inet_ntop,
              inet_4map6, ipv4to6, mask4to6,
              ipanyto6, maskanyto6, ipv6to4,
              packzeros, naip_gethostbyname
:math   =>    hasbits, isIPv4, isNewIPv4, isAnyIPv4,
              addconst, add128, sub128, notcontiguous,
              bin2bcd, bcd2bin, shiftleft
$dotquad = inet_ntoa($netaddr);
$netaddr = inet_aton($dotquad);
$ipv6naddr = ipv6_aton($ipv6_text);
$ipv6_text = ipvt_ntoa($ipv6naddr);
$hex_text = ipv6_n2x($ipv6naddr);
$dec_text = ipv6_n2d($ipv6naddr);
$hex_text = packzeros($hex_text);
$ipv6naddr = inet_any2n($dotquad or $ipv6_text);
$ipv6naddr = inet_4map6($netaddr or $ipv6naddr);
$rv = hasbits($bits128);
$rv = isIPv4($bits128);
$rv = isNewIPv4($bits128);
$rv = isAnyIPv4($bits128);
$dotquad or $hex_text = inet_n2dx($ipv6naddr);
$dotquad or $dec_text = inet_n2ad($ipv6naddr);
$netaddr = inet_pton($AF_family,$hex_text);
$hex_text = inet_ntop($AF_family,$netaddr);
$ipv6naddr = ipv4to6($netaddr);
$ipv6naddr = mask4to6($netaddr);
$ipv6naddr = ipanyto6($netaddr);
$ipv6naddr = maskanyto6($netaddr);
$netaddr = ipv6to4($pv6naddr);
$bitsX2 = shiftleft($bits128,$n);
$carry = addconst($ipv6naddr,$signed_32con);
($carry,$ipv6naddr)=addconst($ipv6naddr,$signed_32con);
$carry = add128($ipv6naddr1,$ipv6naddr2);
($carry,$ipv6naddr)=add128($ipv6naddr1,$ipv6naddr2);
$carry = sub128($ipv6naddr1,$ipv6naddr2);
($carry,$ipv6naddr)=sub128($ipv6naddr1,$ipv6naddr2);
($spurious,$cidr) = notcontiguous($mask128);
$bcdtext = bin2bcd($bits128);
$bits128 = bcd2bin($bcdtxt);
$modetext = mode;
($name,$aliases,$addrtype,$length,@addrs)=naip_gethostbyname(NAME);
$trueif = havegethostbyname2();
NetAddr::IP::Util::lower();
NetAddr::IP::Util::upper();

INSTALLATION

Un-tar the distribution in an appropriate directory and type:

perl Makefile.PL
make
make test
make install

NetAddr::IP::Util installs by default with its primary functions compiled using Perl's XS extensions to build a 'C' library. If you do not have a 'C' complier available or would like the slower Pure Perl version for some other reason, then type:

perl Makefile.PL -noxs
make
make test
make install

DESCRIPTION

NetAddr::IP::Util provides a suite of tools for manipulating and converting IPv4 and IPv6 addresses into 128 bit string context and back to text. The strings can be manipulated with Perl's logical operators:

and     &
or      |
xor     ^
        ~       compliment

in the same manner as 'vec' strings.

The IPv6 functions support all rfc1884 formats.

i.e.  x:x:x:x:x:x:x:x:x
      x:x:x:x:x:x:x:d.d.d.d
      ::x:x:x
      ::x:d.d.d.d
and so on...

$dotquad = inet_ntoa($netaddr);
Convert a packed IPv4 network address to a dot-quad IP address.
```
input:        packed network address
returns:      IP address i.e. 10.4.12.123
```
$netaddr = inet_aton($dotquad);
Convert a dot-quad IP address into an IPv4 packed network address.
```
input:        IP address i.e. 192.5.16.32
returns:      packed network address
```
$ipv6addr = ipv6_aton($ipv6_text);
Takes an IPv6 address of the form described in rfc1884 and returns a 128 bit binary RDATA string.
```
input:        ipv6 text
returns:      128 bit RDATA string
```
$ipv6_text = ipv6_ntoa($ipv6naddr);
Convert a 128 bit binary IPv6 address to compressed rfc 1884 text representation.
```
input:        128 bit RDATA string
returns:      ipv6 text
```
$hex_text = ipv6_n2x($ipv6addr);
Takes an IPv6 RDATA string and returns an 8 segment IPv6 hex address
```
input:        128 bit RDATA string
returns:      x:x:x:x:x:x:x:x
```
$dec_text = ipv6_n2d($ipv6addr);
Takes an IPv6 RDATA string and returns a mixed hex - decimal IPv6 address with the 6 uppermost chunks in hex and the lower 32 bits in dot-quad representation.
```
input:        128 bit RDATA string
returns:      x:x:x:x:x:x:d.d.d.d
```
$ipv6naddr = inet_any2n($dotquad or $ipv6_text);
This function converts a text IPv4 or IPv6 address in text format in any standard notation into a 128 bit IPv6 string address. It prefixes any dot-quad address (if found) with '::' and passes it to ipv6_aton.
```
input:        dot-quad or rfc1844 address
returns:      128 bit IPv6 string
```

$rv = hasbits($bits128);

This function returns true if there are one's present in the 128 bit string and false if all the bits are zero.

i.e.  if (hasbits($bits128)) {
        &do_something;
      }
or    if (hasbits($bits128 & $mask128) {
        &do_something;
      }

This allows the implementation of logical functions of the form of:

      if ($bits128 & $mask128) {
          ...
input:        128 bit IPv6 string
returns:      true if any bits are present

$ipv6naddr = inet_4map6($netaddr or $ipv6naddr
This function returns an ipV6 network address with the first 80 bits set to zero and the next 16 bits set to one, while the last 32 bits are filled with the ipV4 address.
```
input:        ipV4 netaddr
          or  ipV6 netaddr
returns:      ipV6 netaddr
returns: undef on error
```
An ipV6 network address must be in one of the two compatible ipV4 mapped address spaces. i.e.
```
::ffff::d.d.d.d    or    ::d.d.d.d
```
$rv = isIPv4($bits128);
This function returns true if there are no on bits present in the IPv6 portion of the 128 bit string and false otherwise.
```
i.e.  the address must be of the form - ::d.d.d.d
```
Note: this is an old and deprecated ipV4 compatible ipV6 address
$rv = isNewIPv4($bits128);
This function return true if the IPv6 128 bit string is of the form
```
::ffff::d.d.d.d
```
$rv = isAnyIPv4($bits128);
This function return true if the IPv6 bit string is of the form
```
::d.d.d.d       or      ::ffff::d.d.d.d
```
$dotquad or $hex_text = inet_n2dx($ipv6naddr);
This function does the right thing and returns the text for either a dot-quad IPv4 or a hex notation IPv6 address.
```
input:        128 bit IPv6 string
returns:      ddd.ddd.ddd.ddd
          or  x:x:x:x:x:x:x:x
```
$dotquad or $dec_text = inet_n2ad($ipv6naddr);
This function does the right thing and returns the text for either a dot-quad IPv4 or a hex::decimal notation IPv6 address.
```
input:        128 bit IPv6 string
returns:      ddd.ddd.ddd.ddd
          or  x:x:x:x:x:x:ddd.ddd.ddd.dd
```
$netaddr = inet_pton($AF_family,$hex_text);
This function takes an IP address in IPv4 or IPv6 text format and converts it into binary format. The type of IP address conversion is controlled by the FAMILY argument.
$hex_text = inet_ntop($AF_family,$netaddr);
This function takes and IP address in binary format and converts it into text format. The type of IP address conversion is controlled by the FAMILY argument.

NOTE: inet_ntop ALWAYS returns lowercase characters.
$hex_text = packzeros($hex_text);
This function optimizes and rfc 1884 IPv6 hex address to reduce the number of long strings of zero bits as specified in rfc 1884, 2.2 (2) by substituting :: for the first occurence of the longest string of zeros in the address.
$ipv6naddr = ipv4to6($netaddr);
Convert an ipv4 network address into an IPv6 network address.
```
input:        32 bit network address
returns:      128 bit network address
```
$ipv6naddr = mask4to6($netaddr);
Convert an ipv4 network address/mask into an ipv6 network mask.
```
input:        32 bit network/mask address
returns:      128 bit network/mask address
```
NOTE: returns the high 96 bits as one's
$ipv6naddr = ipanyto6($netaddr);
Similar to ipv4to6 except that this function takes either an IPv4 or IPv6 input and always returns a 128 bit IPv6 network address.
```
input:        32 or 128 bit network address
returns:      128 bit network address
```
$ipv6naddr = maskanyto6($netaddr);
Similar to mask4to6 except that this function takes either an IPv4 or IPv6 netmask and always returns a 128 bit IPv6 netmask.
```
input:        32 or 128 bit network mask
returns:      128 bit network mask
```
$netaddr = ipv6to4($pv6naddr);
Truncate the upper 96 bits of a 128 bit address and return the lower 32 bits. Returns an IPv4 address as returned by inet_aton.
```
input:        128 bit network address
returns:      32 bit inet_aton network address
```

$bitsXn = shiftleft($bits128,$n);

input:        128 bit string variable,
              number of shifts [optional]
returns:      bits X n shifts
NOTE: a single shift is performed
      if $n is not specified

addconst($ipv6naddr,$signed_32con);

Add a signed constant to a 128 bit string variable.

input:        128 bit IPv6 string,
              signed 32 bit integer
returns:  scalar      carry
          array       (carry, result)

add128($ipv6naddr1,$ipv6naddr2);

Add two 128 bit string variables.

input:        128 bit string var1,
              128 bit string var2
returns:  scalar      carry
          array       (carry, result)

sub128($ipv6naddr1,$ipv6naddr2);
Subtract two 128 bit string variables.
```
input:        128 bit string var1,
              128 bit string var2
returns:  scalar      carry
          array       (carry, result)
```
Note: The carry from this operation is the result of adding the one's complement of ARG2 +1 to the ARG1. It is logically NOT borrow.
```
i.e.    if ARG1 >= ARG2 then carry = 1
or      if ARG1  < ARG2 then carry = 0
```

($spurious,$cidr) = notcontiguous($mask128);

This function counts the bit positions remaining in the mask when the rightmost '0's are removed.

input:  128 bit netmask
returns true if there are spurious
            zero bits remaining in the
            mask, false if the mask is
            contiguous one's,
        128 bit cidr number

$bcdtext = bin2bcd($bits128);
Convert a 128 bit binary string into binary coded decimal text digits.
```
input:        128 bit string variable
returns:      string of bcd text digits
```

$bits128 = bcd2bin($bcdtxt);

Convert a bcd text string to 128 bit string variable

input:        string of bcd text digits
returns:      128 bit string variable

$modetext = mode;

Returns the operating mode of this module.

input:          none
returns:        "Pure Perl"
           or   "CC XS"

($name,$aliases,$addrtype,$length,@addrs)=naip_gethostbyname(NAME);
Replacement for Perl's gethostbyname if Socket6 is available

In ARRAY context, returns a list of five elements, the hostname or NAME, a space separated list of C_NAMES, AF family, length of the address structure, and an array of one or more netaddr's

In SCALAR context, returns the first netaddr.

This function ALWAYS returns an IPv6 address, even on IPv4 only systems. IPv4 addresses are mapped into IPv6 space in the form:
```
::FFFF:FFFF:d.d.d.d
```
This is NOT the expected result from Perl's gethostbyname2. It is instead equivalent to:
```
On an IPv4 only system:
  $ipv6naddr = ipv4to6 scalar ( gethostbyname( name ));
On a system with Socket6 and a working gethostbyname2:
  $ipv6naddr = gethostbyname2( name, AF_INET6 );
and if that fails, the IPv4 conversion above.
```
For a gethostbyname2 emulator that behave like Socket6, see: Net::DNS::Dig
$trueif = havegethostbyname2();
This function returns TRUE if Socket6 has a functioning gethostbyname2, otherwise it returns FALSE. See the comments above about the behavior of naip_gethostbyname.
NetAddr::IP::Util::lower();
Return IPv6 strings in lowercase.
NetAddr::IP::Util::upper();
Return IPv6 strings in uppercase. This is the default.

EXAMPLES

# convert any textual IP address into a 128 bit vector
#
sub text2vec {
  my($anyIP,$anyMask) = @_;
# not IPv4 bit mask
  my $notiv4 = ipv6_aton('FFFF:FFFF:FFFF:FFFF:FFFF:FFFF::');
  my $vecip   = inet_any2n($anyIP);
  my $mask    = inet_any2n($anyMask);
# extend mask bits for IPv4
  my $bits = 128;     # default
  unless (hasbits($mask & $notiv4)) {
    $mask |= $notiv4;
    $bits = 32;
  }
  return ($vecip, $mask, $bits);
}
... alternate implementation, a little faster
sub text2vec {
  my($anyIP,$anyMask) = @_;
# not IPv4 bit mask
  my $notiv4 = ipv6_aton('FFFF:FFFF:FFFF:FFFF:FFFF:FFFF::');
  my $vecip   = inet_any2n($anyIP);
  my $mask    = inet_any2n($anyMask);
# extend mask bits for IPv4
  my $bits = 128;     # default
  if (isIPv4($mask)) {
    $mask |= $notiv4;
    $bits = 32;
  }
  return ($vecip, $mask, $bits);
}
... elsewhere
  $nip = {
      addr    => $vecip,
      mask    => $mask,
      bits    => $bits,
  };
# return network and broadcast addresses from IP and Mask
#
sub netbroad {
  my($nip) = shift;
  my $notmask = ~ $nip->{mask};
  my $bcast   = $nip->{addr} | $notmask;
  my $network = $nip->{addr} & $nip->{mask};
  return ($network, $broadcast);
}
# check if address is within a network
#
sub within {
  my($nip,$net) = @_;
  my $addr = $nip->{addr}
  my($nw,$bc) = netbroad($net);
# arg1 >= arg2, sub128 returns true
  return (sub128($addr,$nw) && sub128($bc,$addr))
      ? 1 : 0;
}
# truely hard way to do $ip++
# add a constant, wrapping at netblock boundaries
# to subtract the constant, negate it before calling
# 'addwrap' since 'addconst' will extend the sign bits
#
sub addwrap {
  my($nip,$const) = @_;
  my $addr    = $nip->{addr};
  my $mask    = $nip->{mask};
  my $bits    = $nip->{bits};
  my $notmask = ~ $mask;
  my $hibits  = $addr & $mask;
  $addr = addconst($addr,$const);
  my $wraponly = $addr & $notmask;
  my $newip = {
      addr    => $hibits | $wraponly,
      mask    => $mask,
      bits    => $bits,
  };
  # bless $newip as appropriate
  return $newip;
}
# something more useful
# increment a /24 net to the NEXT net at the boundry
my $nextnet = 256;    # for /24
LOOP:
while (...continuing) {
  your code....
  ...
  my $lastip = $ip-copy();
  $ip++;
  if ($ip < $lastip) {        # host part wrapped?
# discard carry
    (undef, $ip->{addr} = addconst($ip->{addr}, $nextnet);
  }
  next LOOP;
}

EXPORT_OK

inet_aton
inet_ntoa
ipv6_aton
ipv6_ntoa
ipv6_n2x
ipv6_n2d
inet_any2n
hasbits
isIPv4
isNewIPv4
isAnyIPv4
inet_n2dx
inet_n2ad
inet_pton
inet_ntop
inet_4map6
ipv4to6
mask4to6
ipanyto6
maskanyto6
ipv6to4
packzeros
shiftleft
addconst
add128
sub128
notcontiguous
bin2bcd
bcd2bin
mode
naip_gethostbyname
havegethostbyname2

AUTHOR

Michael Robinton <michael@bizsystems.com>

COPYRIGHT

This program is free software; you can redistribute it and/or modify it under the terms of either:

a) the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any
later version, or
b) the "Artistic License" which comes with this distribution.

This program 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 either the GNU General Public License or the Artistic License for more details.

You should have received a copy of the Artistic License with this distribution, in the file named "Artistic". If not, I'll be glad to provide one.

You should also have received a copy of the GNU General Public License along with this program in the file named "Copying". If not, write to the

Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor
Boston, MA 02110-1301 USA.

or visit their web page on the internet at:

http://www.gnu.org/copyleft/gpl.html.

AUTHOR

Michael Robinton <michael@bizsystems.com>