NAME

Net::IP::LPM - Perl implementation of Longest Prefix Match algorithm

SYNOPSIS

  use Net::IP::LPM;

  my $lpm = Net::IP::LPM->new();

  # add prefixes 
  $lpm->add('0.0.0.0/0', 'default');
  $lpm->add('::/0', 'defaultv6');
  $lpm->add('147.229.0.0/16', 'net1');
  $lpm->add('147.229.3.0/24', 'net2');
  $lpm->add('147.229.3.10/32', 'host3');
  $lpm->add('147.229.3.11', 'host4');
  $lpm->add('2001:67c:1220::/32', 'net16');
  $lpm->add('2001:67c:1220:f565::/64', 'net26');
  $lpm->add('2001:67c:1220:f565::1235/128', 'host36');
  $lpm->add('2001:67c:1220:f565::1236', 'host46');


  printf $lpm->lookup('147.229.100.100'); # returns net1
  printf $lpm->lookup('147.229.3.10');    # returns host3
  printf $lpm->lookup('2001:67c:1220::1');# returns net16
  

DESCRIPTION

The module Net::IP::LPM implements the Longest Prefix Matxh algo for both IPv4 and IPv6 protocols. The module uses Trie algo.

PERFORMANCE

The module is able to match ~ 1 mln. lookups per second on complete Internet BGP table (aprox 500 000 prefixes) on ordinary hardware (2.4GHz Xeon CPU). For more detail you can try make test on module source to check performance on your system. Module supports both IPv4 and IPv6 protocol.

CLASS METHODS

new - Class Constructor

  $lpm = Net::IP::LPM->new( );

Constructs a new Net::IP::LPM object.

OBJECT METHODS

add - Add Prefix

   $code = $lpm->add( $prefix, $value );

Adds prefix $prefix into database with value $value. Returns 1 if the prefix was added sucesfully. Returns 0 when some error happens (typically wrong address formating).

lookup - Lookup Address

  $value = $lpm->$lookup( $address );

Lookups the prefix in the database and returns the value. If the prefix is not found or error ocured the undef value is returned.

Before lookups are performed the database have to be rebuilded by $lpm->rebuild() operation.

lookup_raw - Lookup Address in raw format

  $value = $lpm->lookup_raw( $address );

Same as $lpm->lookup but takes $address in raw format (result of inet_ntop function). It is more effective than $lpm->lookup, because convertion from text format is not nescessary.

info - Returns information about builded trie

  $ref = $lpm->info();

Returns following items

  ipv4_nodes_total - total number of allocated nodes in trie
  ipv4_nodes_value - number of allocated nodes in trie that have stored some value 
  ipv4_trie_bytes - number of allocated for trie nodes (withnout data)
  ipv6_ - same for IPv6 

finish - Release all data in object

  $lpm->finish();

SEE ALSO

There are also other implementation of Longest Prefix Matxh in perl. However most of them have some disadvantage (poor performance, lack of support for IPv6 or requires a lot of time for initial database building). However in some cases it might be usefull:

Net::IPTrie

Net::IP::Match

Net::IP::Match::Trie

Net::IP::Match-XS

Net::CIDR::Lookup

Net::CIDR::Compare

AUTHOR

Tomas Podermanski <tpoder@cis.vutbr.cz> Brno University of Technology

COPYRIGHT AND LICENSE

Copyright (C) 2012, Brno University of Technology

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

cpanm Net::IP::LPM

perl -MCPAN -e shell
install Net::IP::LPM