The London Perl and Raku Workshop takes place on 26th Oct 2024. If your company depends on Perl, please consider sponsoring and/or attending.

NAME

Device::Firewall::PaloAlto - Interact with the Palo Alto firewall API

VERSION

version 0.1.9

SYNOPSIS

    use Device::Firewall::PaloAlto;

    # Constructon doesn't initiate any comms with the firewall.    
    my $fw = Device::Firewall::PaloAlto->new(
        uri => 'https://pa.localdomain',
        username => 'user11',
        password => 'a_password'
    );

    # Auth is required before performing any actions
    $fw->auth or die "Could not authenticate";

    # Calls can be chained together
    my $proto = $fw
        ->op
        ->virtual_router('default')
        ->route('0.0.0.0/0)
        ->protocol

    # Can use the 'Test' module to test aspects of the firewall.
    # Returns true if both IPs are in the ARP table
    ok( $fw->test->arp( qw(192.0.2.1 192.0.2.2) );
    
    my $flow = $fw->test->secpolicy(
       from => 'Trust', to => 'Untrust',
       src_ip => '192.0.2.1', dst_ip => '203.0.113.1',
       protocol => 6, port => 443
    );

    ok( $flow, 'Flow was allowed' );
    say "Flow hit rule: ".$flow->rulename;

    # Add and remove user ID information on the firewall
    $fw->user_id->add_ip_mapping('192.0.2.1', 'localdomain\greg.foletta');

    # If the module is used in a one liner, fw() sub is exported to make
    # it easier to use, and to_json() automatically prints to STDOUT.
    bash% perl -MDevice::Firewall::PaloAlto -E 'fw()->op->arp_table->to_json'

DESCRIPTION

This module provides an interface to the Palo Alto firewall API.

FUNCTIONS

fw()

This is exported automatically into the main:: namespace if the module is loaded within a one-liner - i.e. the calling script name is '-e'. If the module is loaded within a normal script, this sub is not exported into main (though is of course accessible using Device::Firewall::PaloAlto::fw().)

The purpose of this sub is to reduce the amount of code needed in one liners. As an example

    # Long way
    % perl -MDevice::Firewall::PaloAlto -E 'Device::Firewall::PaloAlto::new(vefify_hostname => 0)->auth->op->system_info->to_json'
    
    # Shorter way
    % perl -MDevice::Firewall::PaloAlto -E 'fw()->op->system_info->to_json'

The sub takes ($user, $pass, $verify) arguments. If $user and $pass arguments are not specified, their undefinedness is passed through to new() and either environment variables are used or they default to 'admin'.

If $verify is not specified, new() is called with verify_hostname = 0>, and thus the TLS certificate is not verified. This is opposite to the default behaviour of new() where the verification is performed.

METHODS

new

    my $fw = Device::Firewall::PaloAlto(
        uri => 'https://pa.localdomain',
        username => 'user',
        password => 'pass',
        verify_hostname => 1
    );

The new() method creates a new Device::Firewall::PaloAlto object. The uri, username and password can be passed in using the environment variables 'PA_FW_URI', PA_FW_USERNAME and PA_FW_PASSWORD. If no environment variables are set, the username and password both default to 'admin'.

auth

    my $fw = $fw->auth;

This function authenticates the credentials passed to new against the firewall.

If successful, it returns the object itself to all method calls to be chains. If unsuccessful, it returns a Class::Error object.

debug

    $fw->debug->op->interfaces();

Enables the debugging of HTTP requests and responses to the firewall.

undebug

Disables debugging.

op

Returns a Device::Firewall::PaloAlto::Op object. This object has methods to perform operational tasks on the firewall.

    my $fw_op = $fw->auth->op();
   
    # Return the firewall's interfaces
    my $interfaces = $fw_op->interfaces();

    # Return the ARP table
    my $arp_table = $fw->op->arp_table();

    # Returns the routes in the guest_vr virtual router
    my $routes = $fw->op->virtual_router('guest_vr');

user_id

Provides access to the Device::Firewall::PaloAlto::UserID module. This module contains subroutines to add and remove dynamic IP to user mappings:

    # Add a mapping
    $fw->user_id->add_ip_mapping('192.0.2.1', 'localdomain\greg.foletta');

    # Remove a mapping
    $fw->user_id->rm_ip_mapping('192.0.2.1', 'localdomain\greg.foletta');

Refer to the module documentation for more information.

test

Provides access to the Device::Firewall::PaloAlto::Test module. This module allows you to test the current state of a firewall.

    use Test::More;
    $test = $fw->test;
    ok( $test->interfaces('ethernet1/1', 'ethernet1/2'), 'Interfaces up' );

ERRORS

Errors are handled differently depending on whether the script is running from a file, or from a 'one-liner'.

File Errors

In the event of an error, a Class::Error object is returned. The module's documentation provides the best information, but essentially it slurps up any method calls, evaluates to false in a boolean context, and contains an error string and code.

This allows you to chain together method calls and the error is propagated all the way through. A suggested way of checking for errors would be:

    my $state = $fw->auth->op->interfaces->interface('ethernet1/1')->state or die $state->error();

One-liner Errors

If the code is being run from a one-liner, the error is immeidately croaked rather than being returned as a Class::Error object. This saves the user from having to add the explicit croak at the end of the call on what it likely an already crowded shell line. An example:

    bash% perl -MDevice::Firewall::PaloAlto -E 'fw()->op->system_info->to_json'         
    HTTP Error: 500 Can't connect to pa.localdomain:443 (certificate verify failed) - 500 at -e line 1.

ENVIRONMENT VARIABLES

The module uses the environment variables PA_FW_URI, PA_FW_USERNAME and PA_FW_PASSWORD. These map to the uri, username and password arguments to the new constructor. If any of these arguments are not present, the environment variable (if defined) is used.

The purpose of these is to reduce the clutter when using the module in a one-liner:

    bash% export PA_FW_URI=https://pa.localdomain
    bash% export PA_FW_USERNAME=greg.foletta
    bash% export PA_FW_PASSWORD=a_complex_password
    bash% perl -MDevice::Firewall::PaloAlto -E 'say fw()->op->interfaces->to_json'

JSON

Most objects inherit the to_json method which returns a JSON representation of the object. By default the JSON is printed to STDOUT, however a filename can be pased instead.

    # Outputs the json to STDOUT
    $fw->op->system_info->to_json;

    # Outputs the json the file 'firewall_info.json' in the current working directory
    $fw->op->system_info->to_json('firewall_info.json');

AUTHOR

Greg Foletta <greg@foletta.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2019 by Greg Foletta.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.