tcllib_ip(3)

tcllib_ip(3tcl) Domain Name Service tcllib_ip(3tcl)

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NAME
tcllib_ip - IPv4 and IPv6 address manipulation

SYNOPSIS
package require Tcl 8.2

package require ip ?1.4?

::ip::version address

::ip::is class address

::ip::equal address address

::ip::normalize address

::ip::contract address

::ip::distance ipaddr1 ipaddr2

::ip::nextIp ipaddr ?offset?

::ip::prefix address

::ip::type address

::ip::mask address

::ip::prefixToNative prefix

::ip::nativeToPrefix nativeList|native ?-ipv4?

::ip::intToString number ?-ipv4?

::ip::toInteger ipaddr

::ip::toHex ipaddr

::ip::maskToInt ipmask

::ip::broadcastAddress prefix ?-ipv4?

::ip::maskToLength dottedMask|integerMask|hexMask ?-ipv4?

::ip::lengthToMask maskLength ?-ipv4?

::ip::nextNet ipaddr ipmask ?count? ?-ipv4?

::ip::isOverlap prefix prefix...

::ip::isOverlapNative ?-all? ?-inline? ?-ipv4? hexipaddr hexipmask hex-
iplist

::ip::ipToLayer2Multicast ipaddr

::ip::ipHostFromPrefix prefix ?-exclude prefixExcludeList?

::ip::reduceToAggregates prefixlist

::ip::longestPrefixMatch ipaddr prefixlist ?-ipv4?

::ip::collapse prefixlist

::ip::subtract prefixlist

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DESCRIPTION
This package provides a set of commands to help in parsing, displaying
and comparing internet addresses. The package can handle both IPv4 (1)
and IPv6 (2) address types.

COMMANDS
::ip::version address
Returns the protocol version of the address (4 or 6), or -1 if
the address is neither IPv4 or IPv6.

::ip::is class address
Returns true if the address is a member of the given protocol
class. The class parameter may be either ipv4 or ipv6 This is
effectively a boolean equivalent of the version command. The
class argument may be shortened to 4 or 6.

::ip::equal address address
Compare two address specifications for equivalence. The argu-
ments are normalized and the address prefix determined (if a
mask is supplied). The normalized addresses are then compared
bit-by-bit and the procedure returns true if they match.

::ip::normalize address
Convert an IPv4 or IPv6 address into a fully expanded version.
There are various shorthand ways to write internet addresses,
missing out redundant parts or digits. This procedure is the op-
posite of contract.

::ip::contract address
Convert a normalized internet address into a more compact form
suitable for displaying to users.

::ip::distance ipaddr1 ipaddr2
This command computes the (integer) distance from IPv4 address
ipaddr1 to IPv4 address ipaddr2, i.e. "ipaddr2 - ipaddr1"

% ::ip::distance 1.1.1.1 1.1.1.5
4

::ip::nextIp ipaddr ?offset?
This command adds the integer offset to the IPv4 address ipaddr
and returns the new IPv4 address.

% ::ip::distance 1.1.1.1 4
1.1.1.5

::ip::prefix address
Returns the address prefix generated by masking the address part
with the mask if provided. If there is no mask then it is equiv-
alent to calling normalize

::ip::type address

::ip::mask address
If the address supplied includes a mask then this is returned
otherwise returns an empty string.

::ip::prefixToNative prefix
This command converts the string prefix from dotted form
(<ipaddr>/<mask> format) to native (hex) form. Returns a list
containing two elements, ipaddress and mask, in this order, in
hexadecimal notation.

% ip::prefixToNative 1.1.1.0/24
0x01010100 0xffffff00

::ip::nativeToPrefix nativeList|native ?-ipv4?
This command converts from native (hex) form to dotted form. It
is the complement of ::ip::prefixToNative.

list nativeList (in)
List of several ip addresses in native form. The native
form is a list as returned by ::ip::prefixToNative.

list native (in)
A list as returned by ::ip::prefixToNative.

The command returns a list of addresses in dotted form if it was called
with a list of addresses. Otherwise a single address in dotted form is
returned.

% ip::nativeToPrefix {0x01010100 0xffffff00} -ipv4
1.1.1.0/24

::ip::intToString number ?-ipv4?
This command converts from an ip address specified as integer
number to dotted form.

ip::intToString 4294967295
255.255.255.255

::ip::toInteger ipaddr
This command converts a dotted form ip into an integer number.

% ::ip::toInteger 1.1.1.0
16843008

::ip::toHex ipaddr
This command converts dotted form ip into a hexadecimal number.

% ::ip::toHex 1.1.1.0
0x01010100

::ip::maskToInt ipmask
This command convert an ipmask in either dotted (255.255.255.0)
form or mask length form (24) into an integer number.

::ip::maskToInt 24
4294967040

::ip::broadcastAddress prefix ?-ipv4?
This commands returns a broadcast address in dotted form for the
given route prefix, either in the form "addr/mask", or in native
form. The result is in dotted form.

::ip::broadcastAddress 1.1.1.0/24
1.1.1.255

::ip::broadcastAddress {0x01010100 0xffffff00}
0x010101ff

::ip::maskToLength dottedMask|integerMask|hexMask ?-ipv4?
This command converts the dotted or integer form of an ipmask to
the mask length form.

::ip::maskToLength 0xffffff00 -ipv4
24

% ::ip::maskToLength 255.255.255.0
24

::ip::lengthToMask maskLength ?-ipv4?
This command converts an ipmask in mask length form to its dot-
ted form.

::ip::lengthToMask 24
255.255.255.0

::ip::nextNet ipaddr ipmask ?count? ?-ipv4?
This command returns an ipaddress in the same position in the
count next network. The default value for count is 1.

The address can be specified as either integer number or in dot-
ted form. The mask can be specified as either integer number,
dotted form, or mask length form.

The result is in hex form.

::ip::isOverlap prefix prefix...
This command checks if the given ip prefixes overlap. All argu-
ments are in dotted "addr/mask" form. All arguments after the
first prefix are compared against the first prefix. The result
is a boolean value. It is true if an overlap was found for any
of the prefixes.

% ::ip::isOverlap 1.1.1.0/24 2.1.0.1/32
0

::ip::isOverlap 1.1.1.0/24 2.1.0.1/32 1.1.1.1/32
1

::ip::isOverlapNative ?-all? ?-inline? ?-ipv4? hexipaddr hexipmask hex-
iplist
This command is similar to ::ip::isOverlap, however the argu-
ments are in the native form, and the form of the result is un-
der greater control of the caller. If the option -all is speci-
fied it checks all addresses for overlap, not only until the
first one is found. If the option -inline is specified the com-
mand returns the overlapping prefix instead of index values.

The result of the command is, depending on the specified op-
tions,

no options
The index of the first overlap found, or 0 if there is
none.

-all A list containing the indices of all overlaps found, or
an empty list if there are none.

-inline
The first overlapping prefix, or an empoty string if
there is none.

-all -inline
A list containing the prefixes of all overlaps found, or
an empty list if there are none.

% ::ip::isOverlapNative 0x01010100 0xffffff00 {{0x02010001 0xffffffff}}
0

% ::ip::isOverlapNative 0x01010100 0xffffff00 {{0x02010001 0xffffffff} {0x01010101 0xffffffff}}
2

::ip::ipToLayer2Multicast ipaddr
This command an converts ipv4 address in dotted form into a
layer 2 multicast address, also in dotted form.

% ::ip::ipToLayer2Multicast 224.0.0.2
01.00.5e.00.00.02

::ip::ipHostFromPrefix prefix ?-exclude prefixExcludeList?
This command returns a host address from a prefix in the form
"ipaddr/masklen", also making sure that the result is not an ad-
dress found in the prefixExcludeList. The result is an ip ad-
dress in dotted form.

%::ip::ipHostFromPrefix 1.1.1.5/24
1.1.1.1

%::ip::ipHostFromPrefix 1.1.1.1/32
1.1.1.1

::ip::reduceToAggregates prefixlist
This command finds nets that overlap and filters out the more
specific nets. The prefixes are in either addr/mask form or in
native format. The result is a list containing the non-overlap-
ping ip prefixes from the input.

% ::ip::reduceToAggregates {1.1.1.0/24 1.1.0.0/8 2.1.1.0/24 1.1.1.1/32 }
1.0.0.0/8 2.1.1.0/24

::ip::longestPrefixMatch ipaddr prefixlist ?-ipv4?
This command finds longest prefix match from set of prefixes,
given a specific host address. The prefixes in the list are in
either native or dotted form, whereas the host address is in ei-
ther ipprefix format, dotted form, or integer form. The result
is the prefix which is the most specific match to the host ad-
dress.

% ::ip::longestPrefixMatch 1.1.1.1 {1.1.1.0/24 1.0.0.0/8 2.1.1.0/24 1.1.1.0/28 }
1.1.1.0/28

::ip::collapse prefixlist
This commands takes a list of prefixes and returns a list pre-
fixes with the largest possible subnet masks covering the input,
in this manner collapsing adjacent prefixes into larger ranges.

This is different from ::ip::reduceToAggregates in that the lat-
ter only removes specific nets from a list when they are covered
by other elements of the input whereas this command actively
merges nets into larger ranges when they are adjacent to each
other.

% ::ip::collapse {1.2.2.0/24 1.2.3.0/24}
1.2.2.0/23

::ip::subtract prefixlist
This command takes a list of prefixes, some of which are pre-
fixed by a dash. These latter negative prefixes are used to
punch holes into the ranges described by the other, positive,
prefixes. I.e. the negative prefixes are subtracted frrom the
positive ones, resulting in a larger list of describes describ-
ing the covered ranges only as positives.

EXAMPLES
% ip::version ::1
6
% ip::version 127.0.0.1
4

% ip::normalize 127/8
127.0.0.0/8
% ip::contract 192.168.0.0
192.168
%
% ip::normalize fec0::1
fec0:0000:0000:0000:0000:0000:0000:0001
% ip::contract fec0:0000:0000:0000:0000:0000:0000:0001
fec0::1

% ip::equal 192.168.0.4/16 192.168.0.0/16
1
% ip::equal fec0::1/10 fec0::fe01/10
1

REFERENCES
[1] Postel, J. "Internet Protocol." RFC 791, September 1981,
(http://www.ietf.org/rfc/rfc791.txt)

[2] Hinden, R. and Deering, S., "Internet Protocol Version 6 (IPv6)
Addressing Architecture", RFC 3513, April 2003
(http://www.ietf.org/rfc/rfc3513.txt)

AUTHORS
Pat Thoyts

BUGS, IDEAS, FEEDBACK
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