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>

Source file:	NetAddr::IP::Util.3pm.en.gz (from perl-NetAddr-IP 4.079-7.el8)
Source last updated:	2021-04-22 22:29:28
Converted to HTML:	2024-06-22 22:16:22

NAME¶

SYNOPSIS¶

INSTALLATION¶

DESCRIPTION¶

EXAMPLES¶

EXPORT_OK¶

AUTHOR¶

COPYRIGHT¶

AUTHOR¶

SEE ALSO¶