Update example filterset to include a basic IPv6 filterset.

While there extend the current IPv4 filterset.
OK sthen@, henning@

src/etc/bgpd.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: bgpd.conf,v 1.10 2010/10/13 08:27:44 sthen Exp $
+# $OpenBSD: bgpd.conf,v 1.11 2010/11/28 17:11:43 claudio Exp $
 # sample bgpd configuration file
 # see bgpd.conf(5)
 
@@ -77,18 +77,35 @@ neighbor 10.2.1.1 {
 	    aes 4e0f2f1b5c4e3c0d0e2f2d3b8c5c8f0b
 }
 
-# filter out prefixes longer than 24 or shorter than 8 bits
+# filter out prefixes longer than 24 or shorter than 8 bits for IPv4
+# and longer than 48 or shorter than 16 bits for IPv6.
 deny from any
 allow from any inet prefixlen 8 - 24
+allow from any inet6 prefixlen 16 - 48
 
 # accept a default route (since the previous rule blocks this)
 #allow from any prefix 0.0.0.0/0
 
-# filter bogus networks
+# filter bogus networks according to RFC5735
+deny from any prefix 0.0.0.0/8 prefixlen >= 8
 deny from any prefix 10.0.0.0/8 prefixlen >= 8
-deny from any prefix 172.16.0.0/12 prefixlen >= 12
-deny from any prefix 192.168.0.0/16 prefixlen >= 16
+deny from any prefix 127.0.0.0/8 prefixlen >= 8
 deny from any prefix 169.254.0.0/16 prefixlen >= 16
+deny from any prefix 172.16.0.0/12 prefixlen >= 12
 deny from any prefix 192.0.2.0/24 prefixlen >= 24
+deny from any prefix 192.168.0.0/16 prefixlen >= 16
+deny from any prefix 198.18.0.0/15 prefixlen >= 15
+deny from any prefix 198.51.100.0/24 prefixlen >= 24
+deny from any prefix 203.0.113.0/24 prefixlen >= 24
 deny from any prefix 224.0.0.0/4 prefixlen >= 4
 deny from any prefix 240.0.0.0/4 prefixlen >= 4
+
+# filter bogus IPv6 networks according to IANA
+deny from any prefix ::/8 prefixlen >= 8
+deny from any prefix 2001:db8::/32 prefixlen >= 32	# docu range [RFC3849]
+deny from any prefix 2001:10::/28 prefixlen >= 28	# ORCHID [RFC4843]
+deny from any prefix 3ffe::/16 prefixlen >= 16		# old 6bone
+deny from any prefix fc00::/7 prefixlen >= 7		# unique local unicast
+deny from any prefix fe80::/10 prefixlen >= 10		# link local unicast
+deny from any prefix fec0::/10 prefixlen >= 10		# old site local unicast
+deny from any prefix ff00::/8 prefixlen >= 8		# multicast