NAME¶
Net::CIDR - Manipulate IPv4/IPv6 netblocks in CIDR notation
SYNOPSIS¶
use Net::CIDR;
use Net::CIDR ':all';
print join("\n",
Net::CIDR::range2cidr("192.68.0.0-192.68.255.255",
"10.0.0.0-10.3.255.255"))
. "\n";
#
# Output from above:
#
# 192.68.0.0/16
# 10.0.0.0/14
print join("\n",
Net::CIDR::range2cidr(
"dead:beef::-dead:beef:ffff:ffff:ffff:ffff:ffff:ffff"))
. "\n";
#
# Output from above:
#
# dead:beef::/32
print join("\n",
Net::CIDR::range2cidr("192.68.1.0-192.68.2.255"))
. "\n";
#
# Output from above:
#
# 192.68.1.0/24
# 192.68.2.0/24
print join("\n", Net::CIDR::cidr2range("192.68.0.0/16")) . "\n";
#
# Output from above:
#
# 192.68.0.0-192.68.255.255
print join("\n", Net::CIDR::cidr2range("dead::beef::/46")) . "\n";
#
# Output from above:
#
# dead:beef::-dead:beef:3:ffff:ffff:ffff:ffff:ffff
@list=("192.68.0.0/24");
@list=Net::CIDR::cidradd("192.68.1.0-192.68.1.255", @list);
print join("\n", @list) . "\n";
#
# Output from above:
#
# 192.68.0.0/23
print join("\n", Net::CIDR::cidr2octets("192.68.0.0/22")) . "\n";
#
# Output from above:
#
# 192.68.0
# 192.68.1
# 192.68.2
# 192.68.3
print join("\n", Net::CIDR::cidr2octets("dead::beef::/46")) . "\n";
#
# Output from above:
#
# dead:beef:0000
# dead:beef:0001
# dead:beef:0002
# dead:beef:0003
@list=("192.68.0.0/24");
print Net::CIDR::cidrlookup("192.68.0.12", @list);
#
# Output from above:
#
# 1
@list = Net::CIDR::addr2cidr("192.68.0.31");
print join("\n", @list);
#
# Output from above:
#
# 192.68.0.31/32
# 192.68.0.30/31
# 192.68.0.28/30
# 192.68.0.24/29
# 192.68.0.16/28
# 192.68.0.0/27
# 192.68.0.0/26
# 192.68.0.0/25
# 192.68.0.0/24
# 192.68.0.0/23
# [and so on]
print Net::CIDR::addrandmask2cidr("195.149.50.61", "255.255.255.248")."\n";
#
# Output from above:
#
# 195.149.50.56/29
DESCRIPTION¶
The Net::CIDR package contains functions that manipulate lists of IP netblocks
expressed in CIDR notation. The Net::CIDR functions handle both IPv4 and IPv6
addresses.
@cidr_list=Net::CIDR::range2cidr(@range_list);¶
Each element in the @range_list is a string "start-finish", where
"start" is the first IP address and "finish" is the last
IP address.
range2cidr() converts each range into an equivalent CIDR
netblock. It returns a list of netblocks except in the case where it is given
only one parameter and is called in scalar context.
For example:
@a=Net::CIDR::range2cidr("192.68.0.0-192.68.255.255");
The result is a one-element array, with $a[0] being "192.68.0.0/16".
range2cidr() processes each "start-finish" element in
@range_list separately. But if invoked like so:
$a=Net::CIDR::range2cidr("192.68.0.0-192.68.255.255");
The result is a scalar "192.68.0.0/16".
Where each element cannot be expressed as a single CIDR netblock
range2cidr() will generate as many CIDR netblocks as are necessary to
cover the full range of IP addresses. Example:
@a=Net::CIDR::range2cidr("192.68.1.0-192.68.2.255");
The result is a two element array:
("192.68.1.0/24","192.68.2.0/24");
@a=Net::CIDR::range2cidr(
"d08c:43::-d08c:43:ffff:ffff:ffff:ffff:ffff:ffff");
The result is an one element array: ("d08c:43::/32") that reflects
this IPv6 netblock in CIDR notation.
range2cidr() does not merge adjacent or overlapping netblocks in
@range_list.
@range_list=Net::CIDR::cidr2range(@cidr_list);¶
The
cidr2range() functions converts a netblock list in CIDR notation to a
list of "start-finish" IP address ranges:
@a=Net::CIDR::cidr2range("10.0.0.0/14", "192.68.0.0/24");
The result is a two-element array: ("10.0.0.0-10.3.255.255",
"192.68.0.0-192.68.0.255").
@a=Net::CIDR::cidr2range("d08c:43::/32");
The result is a one-element array:
("d08c:43::-d08c:43:ffff:ffff:ffff:ffff:ffff:ffff").
cidr2range() does not merge adjacent or overlapping netblocks in
@cidr_list.
@netblock_list = Net::CIDR::addr2cidr($address);¶
The addr2cidr function takes an IP address and returns a list of all the CIDR
netblocks it might belong to:
@a=Net::CIDR::addr2cidr('192.68.0.31');
The result is a thirtythree-element array: ('192.68.0.31/32', '192.68.0.30/31',
'192.68.0.28/30', '192.68.0.24/29',
[and so on]) consisting of all the possible subnets containing this address
from 0.0.0.0/0 to address/32.
Any addresses supplied to addr2cidr after the first will be ignored. It works
similarly for IPv6 addresses, returning a list of one hundred and twenty nine
elements.
$cidr=Net::CIDR::addrandmask2cidr($address, $netmask);¶
The addrandmask2cidr function takes an IP address and a netmask, and returns the
CIDR range whose size fits the netmask and which contains the address. It is
an error to supply one parameter in IPv4-ish format and the other in IPv6-ish
format, and it is an error to supply a netmask which does not consist solely
of 1 bits followed by 0 bits. For example, '255.255.248.192' is an invalid
netmask, as is '255.255.255.32' because both contain 0 bits in between 1 bits.
Technically speaking both of those *are* valid netmasks, but a) you'd have to be
insane to use them, and b) there's no corresponding CIDR range.
@octet_list=Net::CIDR::cidr2octets(@cidr_list);¶
cidr2octets() takes @cidr_list and returns a list of leading octets
representing those netblocks. Example:
@octet_list=Net::CIDR::cidr2octets("10.0.0.0/14", "192.68.0.0/24");
The result is the following five-element array: ("10.0",
"10.1", "10.2", "10.3", "192.68.0").
For IPv6 addresses, the hexadecimal words in the resulting list are zero-padded:
@octet_list=Net::CIDR::cidr2octets("::dead:beef:0:0/110");
The result is a four-element array:
("0000:0000:0000:0000:dead:beef:0000",
"0000:0000:0000:0000:dead:beef:0001",
"0000:0000:0000:0000:dead:beef:0002",
"0000:0000:0000:0000:dead:beef:0003"). Prefixes of IPv6 CIDR blocks
should be even multiples of 16 bits, otherwise they can potentially expand out
to a 32,768-element array, each!
@cidr_list=Net::CIDR::cidradd($block, @cidr_list);¶
The
cidradd() functions allows a CIDR list to be built one CIDR netblock
at a time, merging adjacent and overlapping ranges. $block is a single
netblock, expressed as either "start-finish", or
"address/prefix". Example:
@cidr_list=Net::CIDR::range2cidr("192.68.0.0-192.68.0.255");
@cidr_list=Net::CIDR::cidradd("10.0.0.0/8", @cidr_list);
@cidr_list=Net::CIDR::cidradd("192.68.1.0-192.68.1.255", @cidr_list);
The result is a two-element array: ("10.0.0.0/8",
"192.68.0.0/23"). IPv6 addresses are handled in an analogous
fashion.
$found=Net::CIDR::cidrlookup($ip, @cidr_list);¶
Search for $ip in @cidr_list. $ip can be a single IP address, or a netblock in
CIDR or start-finish notation.
lookup() returns 1 if $ip overlaps any
netblock in @cidr_list, 0 if not.
$ip=Net::CIDR::cidrvalidate($ip);¶
Validate whether $ip is a valid IPv4 or IPv6 address, or a CIDR. Returns its
argument or undef. Spaces are removed, and IPv6 hexadecimal address are
converted to lowercase.
If $ip contains a "/", it must be a valid CIDR, otherwise it must be a
valid IPv4 or an IPv6 address.
A technically invalid CIDR, such as "192.168.0.1/24" fails validation,
returning undef.
BUGS¶
Garbage in, garbage out. Always use
cidrvalidate() before doing anything
with untrusted input. Otherwise, "slightly" invalid input will work
(extraneous whitespace is generally OK), but the functions will croak if
you're totally off the wall.
AUTHOR¶
Sam Varshavchik <sam@email-scan.com>
With some contributions from David Cantrell <david@cantrell.org.uk>