74 lines
1.9 KiB
Perl
74 lines
1.9 KiB
Perl
#!/usr/local/bin/perl
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# for best results, bring up all your interfaces before running this
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open(I, "ifconfig -a|") || die $!;
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while (<I>) {
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chop;
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if (/^[a-zA-Z]+\d+:/) {
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($iface = $_) =~ s/^([a-zA-Z]+\d+).*/$1/;
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$ifaces{$iface} = $iface;
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next;
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}
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if (/inet/) {
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if (/\-\-\>/) { # PPP, (SLIP?)
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($inet{$iface} = $_) =~ s/.*inet ([^ ]+) \-\-\> ([^ ]+).*/$1/;
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($ppp{$iface} = $_) =~ s/.*inet ([^ ]+) \-\-\> ([^ ]+).*/$2/;
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} else {
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($inet{$iface} = $_) =~ s/.*inet ([^ ]+).*/$1/;
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}
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}
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if (/netmask/) {
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($mask = $_) =~ s/.*netmask ([^ ]+).*/$1/;
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$mask =~ s/^/0x/ if ($mask =~ /^[0-9a-f]*$/);
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$netmask{$iface} = $mask;
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}
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if (/broadcast/) {
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($bcast{$iface} = $_) =~ s/.*broadcast ([^ ]+).*/$1/;
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}
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}
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foreach $i (keys %ifaces) {
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$net{$i} = $inet{$i}."/".$netmask{$i} if (defined($inet{$i}));
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}
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#
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# print out route suggestions
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#
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print "#\n";
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print "# The following routes should be configured, if not already:\n";
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print "#\n";
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foreach $i (keys %ifaces) {
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next if (($i =~ /lo/) || !defined($net{$i}) || defined($ppp{$i}));
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print "# route add $inet{$i} localhost 0\n";
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}
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print "#\n";
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#
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# print out some generic filters which people should use somewhere near the top
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#
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print "block in log quick from any to any with ipopts\n";
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print "block in log quick proto tcp from any to any with short\n";
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$grpi = 0;
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foreach $i (keys %ifaces) {
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if (!defined($inet{$i})) {
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next;
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}
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$grpi += 100;
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$grpo = $grpi + 50;
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if ($i !~ /lo/) {
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print "pass out on $i all head $grpo\n";
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print "block out from 127.0.0.0/8 to any group $grpo\n";
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print "block out from any to 127.0.0.0/8 group $grpo\n";
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print "block out from any to $inet{$i}/32 group $grpo\n";
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print "pass in on $i all head $grpi\n";
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print "block in from 127.0.0.0/8 to any group $grpi\n";
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print "block in from $inet{$i}/32 to any group $grpi\n";
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foreach $j (keys %ifaces) {
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if ($i ne $j && $j !~ /^lo/ && defined($net{$j})) {
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print "block in from $net{$j} to any group $grpi\n";
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}
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}
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}
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}
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