IPTables::libiptc - Perl extension for iptables libiptc
use IPTables::libiptc; $table = IPTables::libiptc::init('filter'); $table->create_chain("mychain"); # Its important to commit/push-back the changes to the kernel $table->commit();
This package provides a perl interface to the netfilter/iptables C-code and library
Advantages of this module: Many rule changes can be done very fast. Several rule changes is committed atomically.
This module is heavily inspired by the CPAN module IPTables-IPv4. The CPAN module IPTables-IPv4 could not be used because it has not been kept up-to-date, with the newest iptables extensions. This is a result of the module design, as it contains every extension and thus needs to port them individually.
This package has another approach, it links with the systems libiptc.a library and depend on dynamic loading of iptables extensions available on the system.
The module only exports the libiptc chain manipulation functions. All rule manipulations are done through the iptables.c
do_command function. As iptables.c is not made as a library, the package unfortunately needs to maintain/contain this C file.
The reasoning behind making this module comes from how iptables/libiptc communicate with the kernel. Iptables/libiptc transfers the entire ruleset from kernel to userspace, and back again after making some changes to the ruleset.
This is a fairly large operation if only changing a single rule. That is actually the behavior of the iptables command.
Thus, with this knowledge it make sense to make several changes before commit'ing the changes (entire ruleset) back to the kernel. This is the behavior/purpose of this perl module.
This is also what makes it so very fast to many rule changes. And gives the property of several rule changes being committed atomically.
Most methods will return 1 for success, or 0 for failure (and on failure, set $! to a string describing the reason for the failure). Unless otherwise noted, you can assume that all methods will use this convention.
my ($policy) = $table->get_policy('chainname'); my ($policy, $pkt_cnt, $byte_cnt) = $table->get_policy('chainname');
This returns an array containing the default policy, and the number of packets and bytes which have reached the default policy, in the chain
chainname does not exist, or if it is not a built-in chain, an empty array will be returned, and $! will be set to a string containing the reason.
$success = $table->set_policy('chainname', 'target'); $success = $table->set_policy('chainname', 'target', 'pkt_cnt', 'byte_cnt'); ($success, $old_policy, $old_pkt_cnt, $old_pkt_cnt) = $table->set_policy('chainname', 'target');
Sets the default policy.
set_policy can be called several ways. Upon success full setting of the policy the old policy and counters are returned. The counter setting values are optional.
$success = $table->create_chain('chainname');
$success = $table->is_chain('chainname');
Checks if the chain exist.
$success = $table->builtin('chainname');
Tests if the chainname is a buildin chain.
$success = $table->delete_chain('chainname');
Tries to delete the chain, returns false if it could not.
$refs = $table->get_references('chainname');
Get a count of how many rules reference/jump to this chain.
@array = $table->list_chains(); $number_of_chains = $table->list_chains();
Lists all chains. Returns the number of chains in SCALAR context.
@array = $table->list_rules_IPs('type', 'chainname'); $number_of_rules = $table->list_rules_IPs('type', 'chainname');
This function lists the (rules) source or destination IPs from a given chain. The
type is either
dst for source and destination IPs. The netmask is also listed together with the IPs, but separated by a
/ character. If chainname does not exist
undef is returned.
No rules manipulation functions is mapped/export from libiptc, instead the iptables
do_command function is exported to this purpose.
Example of an array which contains a command:
my @array = ("-I", "test", "-s", "18.104.22.168", "-j", "ACCEPT"); $table->iptables_do_command(\@array);
None by default.
Module source also available here: https://github.com/netoptimizer/CPAN-IPTables-libiptc/
The Netfilter/iptables homepage: http://www.netfilter.org
Jesper Dangaard Brouer, <firstname.lastname@example.org> or <email@example.com>.
$LastChangedDate$ $Revision$ $LastChangedBy$
Copyright (C) 2006-2011 by Jesper Dangaard Brouer
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.