#!/usr/bin/perl

use strict;

## these may need to be fully qualified unless they are on the path
my $rndc     = "/usr/sbin/rndc";

## location and name of the generated zone
my $spewsbase  = "spews.org";
my $spewszone  = "blackholes";
my $spews      = "$spewszone.$spewsbase";
my $zone       = "/var/named/named.$spews";

## which level do we want
my $level      = 'spews_list_level1.txt.bz2';

# Do we bounce or not? 75 = TEMPFAIL
my $error = 75;

my $time       = time();
my $logfile    = "/var/log/spews.log";
my $filename   = "/tmp/spews.data";


my $heading    = "\$TTL 86400  ;1 day
\$ORIGIN $spewsbase.
$spewszone      IN      SOA ns.$spews. root.$spews. (
                $time       ;serial number
                14400       ;refresh every 4 hours
                3600        ;retry after 1 hour
                864000      ;expire after 10 days
                3600  )     ;negative cache ttl
                IN      NS      ns.$spews.
\$ORIGIN $spews.
ns              IN      A       127.0.0.1
";

open LOGFILE, ">>$logfile";
print LOGFILE "[" . localtime($time) . "] Start processing, fetch the spews list\n";

#
# fetch spews list, bunzip2
#
system("curl http://spews.org/$level 2>/dev/null | bzcat >$filename");

#
# reformat for the sort
#
print LOGFILE "[" . localtime($time) . "] Reformat for sort\n";
open OUTFILE, ">$filename.sort";
open STREAM, "<$filename";
while (<STREAM>) {
    if (/(.*?)\/(.*?) .*\] (.*)/) {
        my $ip   = $1;
        my $cidr = $2;
        my $who  = $3;
        print OUTFILE "$cidr $ip $who\n";
    }
}
close STREAM;
close OUTFILE;

#
# sort based on cidr block size and create zone file
#
print LOGFILE "[" . localtime($time) . "] Sort and create zone file\n";
system("mv -f $zone $zone.save");
open OUTFILE, ">$zone";
open STREAM, "sort <$filename.sort|";
$error = 0;
print OUTFILE "$heading";
my $cidr = '(.*?) ';                        ## match the cidr block size
my $ip   = '(.*?)\.(.*?)\.(.*?)\.(.*?) ';   ## match the ip address
my $who  = '(.*)';                          ## match the txt part
my %snum2txt;
my %net162obj;
my $count = 0;
while (<STREAM>) {
    chomp;
    if (/$cidr$ip$who/oi) {
        $count = $count + 1;
        my $cidrv = $1;
        my $ipa   = $2;
        my $ipb   = $3;
        my $ipc   = $4;
        my $ipd   = $5;
        my $n16   = $ipa * 256 + $ipb;
        my $whov  = $6;
        my $lo;
        my $hi;
        my $pat;
        my $snum;
        if ($whov =~ /.*S(.*)/) { $snum = "S$1"; }
        $snum2txt{$snum} = $whov;

        SWITCH: {
            $lo = 0; $pat = "\*.$ipb.$ipa";
            if ($cidrv == 16) { $hi = $lo +   0;  last SWITCH; }

            $lo = $ipc; $pat = "\*.\$.$ipb.$ipa";
            if ($cidrv == 17) { $hi = $lo + 127;  last SWITCH; }
            if ($cidrv == 18) { $hi = $lo +  63;  last SWITCH; }
            if ($cidrv == 19) { $hi = $lo +  31;  last SWITCH; }
            if ($cidrv == 20) { $hi = $lo +  15;  last SWITCH; }
            if ($cidrv == 21) { $hi = $lo +   7;  last SWITCH; }
            if ($cidrv == 22) { $hi = $lo +   3;  last SWITCH; }
            if ($cidrv == 23) { $hi = $lo +   1;  last SWITCH; }

            $lo = 0; $pat = "\*.$ipc.$ipb.$ipa";
            if ($cidrv == 24) { $hi = $lo +   0;  last SWITCH; }

            $lo = $ipd; $pat = "\$.$ipc.$ipb.$ipa";
            if ($cidrv == 25) { $hi = $lo + 127;  last SWITCH; }
            if ($cidrv == 26) { $hi = $lo +  63;  last SWITCH; }
            if ($cidrv == 27) { $hi = $lo +  31;  last SWITCH; }
            if ($cidrv == 28) { $hi = $lo +  15;  last SWITCH; }
            if ($cidrv == 29) { $hi = $lo +   7;  last SWITCH; }
            if ($cidrv == 30) { $hi = $lo +   3;  last SWITCH; }
            if ($cidrv == 31) { $hi = $lo +   1;  last SWITCH; }

            $lo = 0; $pat = "$ipd.$ipc.$ipb.$ipa";
            if ($cidrv == 32) { $hi = $lo +   0;  last SWITCH; }
        }
        if (!($net162obj{$n16})) { $net162obj{$n16} = netblock->new(); }
        my $obj = $net162obj{$n16};
        ($lo, $hi) = $obj->validate($lo, $hi, $pat);
        if ($lo <= $hi) { print OUTFILE "\$GENERATE $lo-$hi $pat CNAME $snum\n"; }
    }
}
my $item;
foreach $item (keys %snum2txt) {
    print OUTFILE "$item IN A 127.0.0.2\n";
    print OUTFILE " TXT \"$snum2txt{$item}\"\n";
}
close STREAM;
close OUTFILE;
if ($count < 12000) {
    print LOGFILE "[" . localtime($time) . "] Short file.  Aborting!\n";
    close LOGFILE;
    system("mv -f $zone.save $zone");
    exit($error);
}
#system("rm -f $filename");
#system("rm -f $filename.sort");
print LOGFILE "[" . localtime($time) . "] New zone file written: $zone\n";


#
# reload the new zone
#
system("$rndc reload $spews");
print LOGFILE "[" . localtime($time) . "] New zone file loaded: $spews\n";
close LOGFILE;
exit(0);


#
# a helper package to detect
#
package netblock;
    sub new {
        my $invocant = shift;
        my $class = ref($invocant) || $invocant;
        return bless [], $class;
    }

    sub validate {
        my $self = shift;
        my $lo   = shift;
        my $hi   = shift;
        my $pat  = shift;
        if ($pat =~ /(.*?)\.(.*?)\.(.*?)\.(.*?)/) {
            my $ipa = $4;
            my $ipb = $3;
            my $ipc = $2;
            my $ipd = $1;
            my $loo;
            my $hii;
            if ($ipd eq "*") {
                if ($pat =~ /\$/) {
                    $loo = $lo * 256 + 0;
                    $hii = $hi * 256 + 255;
                }
                else {
                    $loo = $ipc * 256 + 0;
                    $hii = $ipc * 256 + 255;
                }
            }
            else {
                if ($pat =~ /\$/) {
                    $loo = $ipc * 256 + $lo;
                    $hii = $ipc * 256 + $hi;
                }
                else {
                    $loo = $ipc * 256 + $ipd;
                    $hii = $loo;
                }
            }
            my $n = scalar(@{$self});
            my $l;
            my $h;
            for (my $i = 0; $i < $n; $i++) {
                $l = $self->[$i][0];
                $h = $self->[$i][1];
                if (($l <= $loo) && ($hii <= $h)) {
                    # don't need this one, it is covered by a duplicate or larger block
                    return (1,0);
                }
                if (($loo <= $l) && ($h <= $hii)) {
                    # we will skip this, a smaller block got here first
                    # should never happen, since we sort by cidr block size
                    return (1,0);
                }
            }
            push @{$self}, [$loo, $hii];
            return ($lo, $hi);
        }
        return (1,0);
    }