Perlbal::Plugin::MaxContentLength - Reject large requests

    LOAD MaxContentLength
    CREATE SERVICE cgilike
        # define a service...
        SET max_content_length  = 100000
        SET plugins             = MaxContentLength
    ENABLE cgilike

package Perlbal::Plugin::MaxContentLength;

use strict;
use warnings;

use Perlbal;

sub load {
    Perlbal::Service::add_tunable(
        max_content_length => {
            check_role => '*',
            check_type => 'int',
            des => "maximum Content-Length allowed, in bytes. 0 for no limit",
            default => 0,
        },
    );
    return 1;
}

use constant HANDLE_REQUEST => 0;
use constant IGNORE_REQUEST => 1;

sub register {
    my ($class, $svc) = @_;

    my $cfg = $svc->{extra_config};
    return unless $cfg;

    $svc->register_hook('MaxContentLength', 'start_http_request' => sub {
        my $client = shift;
        return IGNORE_REQUEST unless $client;

        # allow request if max is disabled
        return HANDLE_REQUEST unless $cfg->{max_content_length};

        my $headers = $client->{req_headers};
        return HANDLE_REQUEST unless $headers;

        # allow requests which don't have a Content-Length header
        my $length = $headers->header('content-length');
        return HANDLE_REQUEST unless $length;

        # allow requests under the cap
        return HANDLE_REQUEST if $length <= $cfg->{max_content_length};

        $client->send_response(413, "Content too long.\n");
        return IGNORE_REQUEST;
    });
}

sub unregister {
    my ($class, $svc) = @_;

    $svc->unregister_hooks('MaxContentLength');
    return 1;
}

1;