cidrexpand revision 363466 
1#!/usr/bin/perl -w
2#
3# usage:
4#  cidrexpand < /etc/mail/access | makemap -r hash /etc/mail/access
5#
6# v 0.4
7#
8# 17 July 2000 Derek J. Balling (dredd@megacity.org)
9#
10# Acts as a preparser on /etc/mail/access_db to allow you to use address/bit
11# notation.
12#
13# If you have two overlapping CIDR blocks with conflicting actions
14# e.g.   10.2.3.128/25 REJECT and 10.2.3.143 ACCEPT
15# make sure that the exceptions to the more general block are specified
16# later in the access_db.
17#
18# the -r flag to makemap will make it "do the right thing"
19#
20# Modifications
21# -------------
22# 26 Jul 2001 Derek Balling (dredd@megacity.org)
23#     Now uses Net::CIDR because it makes life a lot easier.
24#
25#  5 Nov 2002 Richard Rognlie (richard@sendmail.com)
26#     Added code to deal with the prefix tags that may now be included in
27#     the access_db
28#
29#     Added clarification in the notes for what to do if you have
30#     exceptions to a larger CIDR block.
31#
32#  26 Jul 2006 Richard Rognlie (richard@sendmail.com)
33#     Added code to strip "comments" (anything after a non-escaped #)
34#     # characters after a \ or within quotes (single and double) are
35#     left intact.
36#
37#     e.g.
38#	From:1.2.3.4	550 Die spammer # spammed us 2006.07.26
39#     becomes
40#	From:1.2.3.4	550 Die spammer
41#
42#  3 August 2006
43#     Corrected a bug to have it handle the special case of "0.0.0.0/0"
44#     since Net::CIDR doesn't handle it properly.
45#
46#  27 April 2016
47#     Corrected IPv6 handling.  Note that UseCompressedIPv6Addresses must
48#     be turned off for this to work; there are three reasons for this:
49#       1) if the MTA uses compressed IPv6 addresses then CIDR 'cuts'
50#          in the compressed range *cannot* be matched, as the MTA simply
51#          won't look for them.  E.g., there's no way to accurately
52#          match "IPv6:fe80::/64" when for the address "IPv6:fe80::54ad"
53#          the MTA doesn't lookup up "IPv6:fe80:0:0:0"
54#       2) cidrexpand only generates uncompressed addresses, so CIDR
55#          'cuts' to the right of the compressed range won't be matched
56#          either.  Why doesn't it generate compressed address output?
57#          Oh, because:
58#       3) compressed addresses are ambiguous when colon-groups are
59#          chopped off!  You want an access map entry for
60#               IPv6:fe80::0:5420
61#          but not for
62#               IPv6:fe80::5420:1234
63#          ?  Sorry, the former is really
64#               IPv6:fe80::5420
65#          which will also match the latter!
66#
67#  25 July 2016
68#     Since cidrexpand already requires UseCompressedIPv6Addresses to be
69#     turned off, it can also canonicalize non-CIDR IPv6 addresses to the
70#     format that sendmail looks up, expanding compressed addresses and
71#     trimming superfluous leading zeros.
72#
73# Report bugs to: <dredd@megacity.org>
74#
75
76
77use strict;
78use Net::CIDR qw(cidr2octets cidrvalidate);
79use Getopt::Std;
80
81sub print_expanded_v4network;
82sub print_expanded_v6network;
83
84our %opts;
85getopts('ct:', \%opts);
86
87# Delimiter between the key and value
88my $space_re = exists $opts{t} ? $opts{t} : '\s+';
89
90# Regexp that matches IPv4 address literals
91my $ipv4_re = qr"(?:\d+\.){3}\d+";
92
93# Regexp that matches IPv6 address literals, plus a lot more.
94# Further checks are required for verifying that it's really one
95my $ipv6_re = qr"[0-9A-Fa-f:]{2,39}(?:\.\d+\.\d+\.\d+)?";
96
97while (<>)
98{
99    chomp;
100    my ($prefix, $network, $len, $right);
101
102    if ( (/\#/) && $opts{c} )
103    {
104	# print "checking...\n";
105	my $i;
106	my $qtype='';
107	for ($i=0 ; $i<length($_) ; $i++)
108	{
109	    my $ch = substr($_,$i,1);
110	    if ($ch eq '\\')
111	    {
112		$i++;
113		next;
114	    }
115	    elsif ($qtype eq '' && $ch eq '#')
116	    {
117		substr($_,$i) = '';
118		last;
119	    }
120	    elsif ($qtype ne '' && $ch eq $qtype)
121	    {
122		$qtype = '';
123	    }
124	    elsif ($qtype eq '' && $ch =~ /[\'\"]/)
125	    {
126		$qtype = $ch;
127	    }
128	}
129    }
130
131    if (($prefix, $network, $len, $right) =
132	    m!^(|\S+:)(${ipv4_re})/(\d+)(${space_re}.*)$!)
133    {
134	print_expanded_v4network($network, $len, $prefix, $right);
135    }
136    elsif ((($prefix, $network, $len, $right) =
137	    m!^((?:\S+:)?[Ii][Pp][Vv]6:)(${ipv6_re})(?:/(\d+))?(${space_re}.*)$!) &&
138	    (!defined($len) || $len <= 128) &&
139	    defined(cidrvalidate($network)))
140    {
141	print_expanded_v6network($network, $len // 128, $prefix, $right);
142    }
143    else
144    {
145	print "$_\n";
146    }
147}
148
149sub print_expanded_v4network
150{
151    my ($network, $len, $prefix, $suffix) = @_;
152
153    # cidr2octets() doesn't handle a prefix-length of zero, so do
154    # that ourselves
155    foreach my $nl ($len == 0 ? (0..255) : cidr2octets("$network/$len"))
156    {
157	print "$prefix$nl$suffix\n";
158    }
159}
160
161sub print_expanded_v6network
162{
163    my ($network, $len, $prefix, $suffix) = @_;
164
165    # cidr2octets() doesn't handle a prefix-length of zero, so do
166    # that ourselves.  Easiest is to just recurse on bottom and top
167    # halves with a length of 1
168    if ($len == 0) {
169	print_expanded_v6network("::", 1, $prefix, $suffix);
170	print_expanded_v6network("8000::", 1, $prefix, $suffix);
171    }
172    else
173    {
174	foreach my $nl (cidr2octets("$network/$len"))
175	{
176	    # trim leading zeros from each group
177	    $nl =~ s/(^|:)0+(?=[^:])/$1/g;
178	    print "$prefix$nl$suffix\n";
179	}
180    }
181}
182