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#!/usr/local/bin/perl -w
# v 0.2-very-beta
#
# 17 July 2000 Derek J. Balling (dredd@megacity.org)
#
# The $SENDMAIL flag tells the code to lump networks in sendmail format
# if applicable. If this flag is disabled, cidrexpand will literally create
# a single line for each entry, which may or may not be what you want. :)
# makes for a rather large hash table...
#
# Acts as a preparser on /etc/mail/access_db to allow you to use address/bit
# notation. Caveat: the address portion MUST be the start address or your
# results will NOT be what what you want.
#
# If you have two overlapping CIDR blocks with conflicting actions
# e.g. 10.2.3.128/25 REJECT and 10.2.3.143 ACCEPT
# make sure that the exceptions to the more general block are specified
# later in the access_db.
#
# the -r flag to makemap will make it "do the right thing"
#
# Modifications
# -------------
# 5 Nov 2002 Richard Rognlie (richard@sendmail.com)
# Added code to deal with the prefix tags that may now be included in
# the access_db
#
# Added clarification in the notes for what to do if you have
# exceptions to a larger CIDR block.
#
# usage:
# cidrexpand < /etc/mail/access | makemap -r hash /etc/mail/access
#
# Report bugs to: dredd@megacity.org
#
my $spaceregex = '\s+';
while (my $arg = shift @ARGV)
{
if ($arg eq '-t')
{
$spaceregex = shift;
}
}
use strict;
my $SENDMAIL = 1;
while (<>)
{
my ($prefix,$left,$right,$space);
if (! /^(|\S\S*:)(\d+\.){3}\d+\/\d\d?$spaceregex.*/ )
{
print;
}
else
{
($prefix,$left,$space,$right) = /^(|\S\S*:)((?:\d+\.){3}\d+\/\d\d?)($spaceregex)(.*)$/;
my @new_lefts = expand_network($left);
foreach my $nl (@new_lefts)
{
print "$prefix$nl$space$right\n";
}
}
}
sub expand_network
{
my ($network,$mask) = split /\//, shift;
my @diffs = calc_changes($network,$mask);
my ($first,$second,$third,$fourth) = split /\./, $network;
my @rc = ();
for my $f ($first..($first+$diffs[0]))
{
if ( ( $SENDMAIL ) and ($diffs[1] == 255))
{
push @rc, "$f";
}
else
{
for my $s ($second..($second+$diffs[1]))
{
if ( ($SENDMAIL) and ($diffs[2] == 255) )
{
push @rc,"$f\.$s";
}
else
{
for my $t ($third..($third+$diffs[2]))
{
if ( ($SENDMAIL) and ($diffs[3] == 255))
{
push @rc, "$f\.$s\.$t";
}
else
{
for my $fr ($fourth..($fourth+$diffs[3]))
{
push @rc, "$f\.$s\.$t\.$fr";
}
}
}
}
}
}
}
return @rc;
}
sub calc_changes
{
my ($network,$mask) = @_;
my @octs = split /\./, $network;
my ($first,$second,$third,$fourth) = (0,0,0,0);
my $power = 32 - $mask;
if ($mask > 24)
{
$fourth = 2**$power - 1;
}
elsif ($mask > 16)
{
$fourth = 255;
$third = 2**($power-8) - 1;
}
elsif ($mask > 8)
{
$fourth = 255;
$third = 255;
$second = 2**($power-16) - 1;
}
elsif ($mask > 0)
{
$fourth = 255;
$third = 255;
$second = 255;
$first = 2**($power-24) - 1;
}
elsif ($mask == 0)
{
$fourth = 255;
$third = 255;
$second = 255;
$first = 255;
}
return ($first,$second,$third,$fourth);
}
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