reclimit/ans2/ans.pl

	ans.pl revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
#!/usr/bin/env perl
#
# Copyright (C) 2014-2016  Internet Systems Consortium, Inc. ("ISC")
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

use strict;
use warnings;

use IO::File;
use Getopt::Long;
use Net::DNS::Nameserver;

my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
print $pidf "$$\n" or die "cannot write pid file: $!";
$pidf->close or die "cannot close pid file: $!";
sub rmpid { unlink "ans.pid"; exit 1; };

$SIG{INT} = \&rmpid;
$SIG{TERM} = \&rmpid;

my $count = 0;
my $send_response = 0;

sub getlimit {
    if ( -e "ans.limit") {
    open(FH, "<", "ans.limit");
    my $line = <FH>;
    chomp $line;
    close FH;
    if ($line =~ /^\d+$/) {
        return $line;
    }
    }

    return 0;
}

my $localaddr = "10.53.0.2";
my $localport = 5300;
my $verbose = 0;
my $limit = getlimit();

sub reply_handler {
    my ($qname, $qclass, $qtype, $peerhost, $query, $conn) = @_;
    my ($rcode, @ans, @auth, @add);

    print ("request: $qname/$qtype\n");
    STDOUT->flush();

    $count += 1;

    if ($qname eq "count" ) {
    if ($qtype eq "TXT") {
        my ($ttl, $rdata) = (0, "$count");
        my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
        push @ans, $rr;
        print ("\tcount: $count\n");
    }
    $rcode = "NOERROR";
    } elsif ($qname eq "reset" ) {
    $count = 0;
    $send_response = 0;
    $limit = getlimit();
    $rcode = "NOERROR";
    print ("\tlimit: $limit\n");
    } elsif ($qname eq "direct.example.org" ) {
    if ($qtype eq "A") {
        my ($ttl, $rdata) = (3600, $localaddr);
        my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
        push @ans, $rr;
    }
    $rcode = "NOERROR";
    } elsif ($qname eq "indirect1.example.org" ||
         $qname eq "indirect2.example.org" ||
         $qname eq "indirect3.example.org" ||
         $qname eq "indirect4.example.org" ||
         $qname eq "indirect5.example.org" ||
         $qname eq "indirect6.example.org" ||
         $qname eq "indirect7.example.org" ||
         $qname eq "indirect8.example.org") {
    if (! $send_response) {
        my $rr = new Net::DNS::RR("$qname 86400 $qclass NS ns1.1.example.org");
        push @auth, $rr;
    } elsif ($qtype eq "A") {
        my ($ttl, $rdata) = (3600, $localaddr);
        my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
        push @ans, $rr;
    }
    $rcode = "NOERROR";
    } elsif ($qname =~ /^ns1\.(\d+)\.example\.org$/) {
    my $next = $1 + 1;
    if ($limit == 0 || (! $send_response && $next <= $limit)) {
        my $rr = new Net::DNS::RR("$1.example.org 86400 $qclass NS ns1.$next.example.org");
        push @auth, $rr;
    } else {
        $send_response = 1;
        if ($qtype eq "A") {
        my ($ttl, $rdata) = (3600, $localaddr);
        my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
        print("\tresponse: $qname $ttl $qclass $qtype $rdata\n");
        push @ans, $rr;
        }
    }
    $rcode = "NOERROR";
    } else {
    $rcode = "NXDOMAIN";
    }

    # mark the answer as authoritive (by setting the 'aa' flag
    return ($rcode, \@ans, \@auth, \@add, { aa => 1 });
}

GetOptions(
    'port=i' => \$localport,
    'verbose!' => \$verbose,
);

my $ns = Net::DNS::Nameserver->new(
    LocalAddr => $localaddr,
    LocalPort => $localport,
    ReplyHandler => \&reply_handler,
    Verbose => $verbose,
);

$ns->main_loop;