Util(3)
✨ NAME ✨
NetAddr::IP::Util — IPv4/6 and 128 bit number utilities 💖
okay bestie so this is the Util(3) page from User Contributed Perl Documentation, and it's literally the toolbox drawer for everything IP-address-shaped. v4, v6, 128-bit numbers, all of it. buckle up 🎀
🌸 SYNOPSIS 🌸
first thing's first: you gotta import the stuff you want, no cap. like this 👇
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
);but honestly? 🫶 the lazy-girl way is to grab the tag groups instead:
use NetAddr::IP::Util qw(:all :inet :ipv4 :ipv6 :math)and here's what each tag is actually handing you 👑 — these are the exact lineups, don't come for me:
: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
🦋 how you actually call these 🦋
🍓 the conversion girlies
$dotquad = inet_ntoa($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);💅 the vibe checks
$rv = hasbits($bits128);
$rv = isIPv4($bits128);
$rv = isNewIPv4($bits128);
$rv = isAnyIPv4($bits128);✨ the "pick a format, any format" ones
$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);🌈 the v4 <-> v6 glow-ups
$ipv6naddr = ipv4to6($netaddr);
$ipv6naddr = mask4to6($netaddr);
$ipv6naddr = ipanyto6($netaddr);
$ipv6naddr = maskanyto6($netaddr);
$netaddr = ipv6to4($pv6naddr);🧚 the math class (128-bit edition)
$bitsX2 = shiftleft($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);
$modetext = mode;👑 the extras
($name,$aliases,$addrtype,$length,@addrs)=naip_gethostbyname(NAME);
$trueif = havegethostbyname2();
NetAddr::IP::Util::lower();
NetAddr::IP::Util::upper();🎀 INSTALLATION 🎀
okay so step one: un-tar the distribution in an appropriate directory, then literally just:
perl Makefile.PL
make
make test
make install💀 heads up bestie: by default NetAddr::IP::Util installs with its primary functions compiled using Perl's XS extensions to build a 'C' library. that's the fast path.
but say you don't have a 'C' complier available, or you're lowkey just feeling the slower Pure Perl version for some other reason? then it's this instead, no drama:
perl Makefile.PL -noxs
make
make test
make installsame dance, just with -noxs and a whole lot more patience 🌸
💖 DESCRIPTION 💖
okay so NetAddr::IP::Util is literally your little bestie toolbox for manipulating and converting IPv4 and IPv6 addresses into 128 bit string context and back to text again. ✨ And the way these strings work? You can just yeet Perl's logical operators at them:
and &
or |
xor ^
~ complimentexactly the same way you'd do it with vec strings, no cap. 🫶
The IPv6 functions support every single rfc1884 format out there. 👑
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...and so on... iykyk 💅
$dotquad = inet_ntoa($netaddr);— converts a packed IPv4 network address into a dot-quad IP address. 🎀
input: packed network address
returns: IP address i.e. 10.4.12.123$netaddr = inet_aton($dotquad);— takes a dot-quad IP address and turns it 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 in the form described in rfc1884 and hands you back a 128 bit binary RDATA string. literally so useful.
input: ipv6 text
returns: 128 bit RDATA string$ipv6_text = ipv6_ntoa($ipv6naddr);— converts a 128 bit binary IPv6 address into compressed rfc 1884 text representation. 🦋
input: 128 bit RDATA string
returns: ipv6 text$hex_text = ipv6_n2x($ipv6addr);— takes an IPv6 RDATA string and gives you back 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. the versatility honestly? iconic. 🔥
input: 128 bit RDATA string
returns: x:x:x:x:x:x:d.d.d.d$ipv6naddr = inet_any2n($dotquad or $ipv6_text);— this one converts a text IPv4 or IPv6 address in any standard notation into a 128 bit IPv6 string address. it prefixes any dot-quad address (if found) with'::'and passes it toipv6_aton. 🧚
input: dot-quad or rfc1844 address
returns: 128 bit IPv6 string$rv = hasbits($bits128);— returns true if there are one's present in the 128 bit string, and false if all the bits are zero. bestie this is the vibe check for bits. ⭐
i.e. if (hasbits($bits128)) {
&do_something;
}
or if (hasbits($bits128 & $mask128) {
&do_something;
}which is what lets you build logical functions shaped like:
if ($bits128 & $mask128) {
... input: 128 bit IPv6 string
returns: true if any bits are present$ipv6naddr = inet_4map6($netaddr or $ipv6naddr— returns an ipV6 network address with the first 80 bits set to zero and the next 16 bits set to one, while the last 32 bits get filled with the ipV4 address. 🎀
input: ipV4 netaddr
or ipV6 netaddr
returns: ipV6 netaddr
returns: undef on errorAn ipV6 network address has to be in one of the two compatible ipV4 mapped address spaces. i.e. 🌈
::ffff::d.d.d.d or ::d.d.d.d$rv = isIPv4($bits128);— 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.dNote: this is an old and deprecated ipV4 compatible ipV6 address 👀
$rv = isNewIPv4($bits128);— returns true if the IPv6 128 bit string is of the form
::ffff::d.d.d.d$rv = isAnyIPv4($bits128);— returns 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. it's giving "i contain multitudes". ✨
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);— does the right thing and returns the text for either a dot-quad IPv4 or a hex::decimal notation IPv6 address. same energy, different fit. 🦋
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,$hex_text);— takes an IP address in IPv4 or IPv6 text format and converts it into binary format. the type of IP address conversion is controlled by theFAMILYargument. 🎯$hex_text = inet_ntop($AF_family,$netaddr);— takes an IP address in binary format and converts it into text format. the type of IP address conversion is controlled by theFAMILYargument. 🫶
NOTE: inet_ntop ALWAYS returns lowercase characters. lowercase supremacy fr fr 💜
$hex_text = packzeros($hex_text);— optimizes an 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);— converts an ipv4 network address into an IPv6 network address. 🌸
input: 32 bit network address
returns: 128 bit network address$ipv6naddr = mask4to6($netaddr);— converts an ipv4 network address/mask into an ipv6 network mask. 🎀
input: 32 bit network/mask address
returns: 128 bit network/mask addressNOTE: returns the high 96 bits as one's
$ipv6naddr = ipanyto6($netaddr);— similar toipv4to6except this one takes either an IPv4 or IPv6 input and always returns a 128 bit IPv6 network address. lowkey the flexible friend of the group. ⭐
input: 32 or 128 bit network address
returns: 128 bit network address$ipv6naddr = maskanyto6($netaddr);— similar tomask4to6except it 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);— truncates the upper 96 bits of a 128 bit address and returns the lower 32 bits. returns an IPv4 address as returned byinet_aton. ✂️
input: 128 bit network address
returns: 32 bit inet_aton network address$bitsXn = shiftleft($bits128,$n);— shifts left, obvs. 👑
input: 128 bit string variable,
number of shifts [optional]
returns: bits X n shiftsNOTE: a single shift is performed if $n is not specified
addconst($ipv6naddr,$signed_32con);— adds a signed constant to a 128 bit string variable. 🍓
input: 128 bit IPv6 string,
signed 32 bit integer
returns: scalar carry
array (carry, result)add128($ipv6naddr1,$ipv6naddr2);— adds two 128 bit string variables together. 💖
input: 128 bit string var1,
128 bit string var2
returns: scalar carry
array (carry, result)sub128($ipv6naddr1,$ipv6naddr2);— subtracts two 128 bit string variables. 🎀
input: 128 bit string var1,
128 bit string var2
returns: scalar carry
array (carry, result)Note: the carry from this operation is the result of adding the one's complement ofARG2+1 to theARG1. it is logically NOT borrow. don't let anyone tell you otherwise. 💀
i.e. if ARG1 >= ARG2 then carry = 1
or if ARG1 < ARG2 then carry = 0($spurious,$cidr) = notcontiguous($mask128);— 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);— converts 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);— converts a bcd text string back into a 128 bit string variable. the round trip is real. 🔁
input: string of bcd text digits
returns: 128 bit string variable$modetext = mode;— returns the operating mode of this module. main character reveal. 👑
input: none
returns: "Pure Perl"
or "CC XS"($name,$aliases,$addrtype,$length,@addrs)=naip_gethostbyname(NAME);— replacement for Perl'sgethostbynameif 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.dThis 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 💜
$trueif = havegethostbyname2();— returns TRUE if Socket6 has a functioninggethostbyname2, otherwise it returns FALSE. see the comments above about the behavior ofnaip_gethostbyname. 🦋NetAddr::IP::Util::lower();— return IPv6 strings in lowercase. 🌸NetAddr::IP::Util::upper();— return IPv6 strings in uppercase. this is the default, bestie. 💅
💖 EXAMPLES 💖
okay bestie, this is where the page gets iconic — it's all code, and every line is doing main character energy. no skips, no edits, we're keeping the whole flex. 💅
first up: convert any textual IP address into a 128 bit vector. here's the first text2vec pass:
# convert any textual IP address into a 128 bit vector
#
sub text2vec {
my($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, $bits);
}and here's the alternate implementation, a little faster:
... alternate implementation, a little faster
sub text2vec {
my($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);
}then, elsewhere, the vibe is this little stash:
... elsewhere
$nip = {
addr => $vecip,
mask => $mask,
bits => $bits,
};next: return network and broadcast addresses from IP and Mask:
# return network and broadcast addresses from IP and Mask
#
sub netbroad {
my($nip) = shift;
my $notmask = ~ $nip->{mask};
my $bcast = $nip->{addr} | $notmask;
my $network = $nip->{addr} & $nip->{mask};
return ($network, $broadcast);
}check if address is within a network — yes, bestie, this is the whole vibe check:
# check if address is within a network
#
sub within {
my($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;
}and here's the truly 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:
# 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;
}and finally, something more useful — increment a /24 net to the NEXT net at the boundry. yes, the page says “boundry,” and we're keeping it exactly like that 🫶
# 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 ✨
here's the full EXPORT_OK roster, no skips, no cap. every single name stays exactly as-is:
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 🎀
okay legal bestie moment — here's the exact copyright tea, word for word, because this part matters:
Copyright 2003 - 2014, Michael Robinton <michael@bizsystems.com>
All rights reserved.
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 🌸
yep, same guy, same email, the page really lists it twice — and we're keeping both because every detail stays:
Michael Robinton <michael@bizsystems.com> 🫶
🦋 SEE ALSO 🦋
go check out NetAddr::IP(3), NetAddr::IP::Lite(3), and NetAddr::IP::InetBase(3) — that's the whole squad, exactly in that order, periodt ✨
signing off with perl v5.42.0 source/version vibes, dated 2016-05-28, page Util(3) — bye bestie, ily, stay hydrated and keep your masks contiguous 💖💅🦋
📦 where this page comes from
- opensuse-leap 16.0: perl-NetAddr-IP 4.079-bp160.1.13 · Artistic-1.0 or GPL-1.0+
- opensuse-leap 16.0: perl-NetAddr-IP 4.079-bp160.1.13 · Artistic-1.0 or GPL-1.0+
- opensuse-leap 16.0: perl-NetAddr-IP 4.079-bp160.1.13 · Artistic-1.0 or GPL-1.0+
- opensuse-leap 16.0: perl-NetAddr-IP 4.079-bp160.1.13 · Artistic-1.0 or GPL-1.0+
- 💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on : a language model's rewrite of the original, under its terms