contrib/ipfilter/mkfilters

   1 #!/usr/local/bin/perl
   2 # for best results, bring up all your interfaces before running this
   3
   4 if ($^O =~ m/^irix/i)
   5 {
   6     &irix_mkfilters || regular_mkfilters || die $!;
   7 }
   8 else
   9 {
  10     &regular_mkfilters || irix_mkfilters || die $!;
  11 }
  12
  13 foreach $i (keys %ifaces) {
  14         $net{$i} = $inet{$i}."/".$netmask{$i} if (defined($inet{$i}));
  15 }
  16 #
  17 # print out route suggestions
  18 #
  19 print "#\n";
  20 print "# The following routes should be configured, if not already:\n";
  21 print "#\n";
  22 foreach $i (keys %ifaces) {
  23         next if (($i =~ /lo/) || !defined($net{$i}) || defined($ppp{$i}));
  24         print "# route add $inet{$i} localhost 0\n";
  25 }
  26 print "#\n";
  27
  28 #
  29 # print out some generic filters which people should use somewhere near the top
  30 #
  31 print "block in log quick from any to any with ipopts\n";
  32 print "block in log quick proto tcp from any to any with short\n";
  33
  34 $grpi = 0;
  35
  36 foreach $i (keys %ifaces) {
  37         if (!defined($inet{$i})) {
  38                 next;
  39         }
  40
  41         $grpi += 100;
  42         $grpo = $grpi + 50;
  43
  44         if ($i !~ /lo/) {
  45                 print "pass out on $i all head $grpo\n";
  46                 print "block out from 127.0.0.0/8 to any group $grpo\n";
  47                 print "block out from any to 127.0.0.0/8 group $grpo\n";
  48                 print "block out from any to $inet{$i}/32 group $grpo\n";
  49                 print "pass in on $i all head $grpi\n";
  50                 print "block in from 127.0.0.0/8 to any group $grpi\n";
  51                 print "block in from $inet{$i}/32 to any group $grpi\n";
  52                 foreach $j (keys %ifaces) {
  53                         if ($i ne $j && $j !~ /^lo/ && defined($net{$j})) {
  54                                 print "block in from $net{$j} to any group $grpi\n";
  55                         }
  56                 }
  57         }
  58 }
  59
  60 sub irix_mkfilters
  61 {
  62     open(NETSTAT, "/usr/etc/netstat -i|") || return 0;
  63
  64     while (defined($line = <NETSTAT>))
  65     {
  66         if ($line =~ m/^Name/)
  67         {
  68             next;
  69         }
  70         elsif ($line =~ m/^(\S+)/)
  71         {
  72             open(I, "/usr/etc/ifconfig $1|") || return 0;
  73             &scan_ifconfig;
  74             close I;            # being neat... - Allen
  75         }
  76     }
  77     close NETSTAT;                      # again, being neat... - Allen
  78     return 1;
  79 }
  80
  81 sub regular_mkfilters
  82 {
  83     open(I, "ifconfig -a|") || return 0;
  84     &scan_ifconfig;
  85     close I;                    # being neat... - Allen
  86     return 1;
  87 }
  88
  89 sub scan_ifconfig
  90 {
  91     while (<I>) {
  92         chop;
  93         if (/^[a-zA-Z]+\d+:/) {
  94             ($iface = $_) =~ s/^([a-zA-Z]+\d+).*/$1/;
  95             $ifaces{$iface} = $iface;
  96             next;
  97         }
  98         if (/inet/) {
  99             if (/\-\-\>/) { # PPP, (SLIP?)
 100                         ($inet{$iface} = $_) =~ s/.*inet ([^ ]+) \-\-\> ([^ ]+).*/$1/;
 101                         ($ppp{$iface} = $_) =~ s/.*inet ([^ ]+) \-\-\> ([^ ]+).*/$2/;
 102                     } else {
 103                         ($inet{$iface} = $_) =~ s/.*inet ([^ ]+).*/$1/;
 104                     }
 105         }
 106         if (/netmask/) {
 107             ($mask = $_) =~ s/.*netmask ([^ ]+).*/$1/;
 108                     $mask =~ s/^/0x/ if ($mask =~ /^[0-9a-f]*$/);
 109             $netmask{$iface} = $mask;
 110         }
 111         if (/broadcast/) {
 112             ($bcast{$iface} = $_) =~ s/.*broadcast ([^ ]+).*/$1/;
 113         }
 114     }
 115 }
 116