etc: add default IPv6 table and chain definitions

Add definition of table and chains to the optional xtables.conf file.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/etc/xtables.conf b/etc/xtables.conf
index 6aee8aa..7b2b8e5 100644
--- a/etc/xtables.conf
+++ b/etc/xtables.conf
@@ -26,8 +26,42 @@
 	}
 
 	table security {
-		chain INPUT hook NF_INET_LOCAL_IN prio 150
-		chain FORWARD hook NF_INET_FORWARD prio 150
-		chain OUTPUT hook NF_INET_LOCAL_OUT prio 150
+		chain INPUT hook NF_INET_LOCAL_IN prio 50
+		chain FORWARD hook NF_INET_FORWARD prio 50
+		chain OUTPUT hook NF_INET_LOCAL_OUT prio 50
+	}
+}
+
+family ipv6 {
+	table raw {
+		chain PREROUTING hook NF_INET_PRE_ROUTING prio -300
+		chain OUTPUT hook NF_INET_LOCAL_OUT prio -300
+	}
+
+	table mangle {
+		chain PREROUTING hook NF_INET_PRE_ROUTING prio -150
+		chain INPUT hook NF_INET_LOCAL_IN prio -150
+		chain FORWARD hook NF_INET_FORWARD prio -150
+		chain OUTPUT hook NF_INET_LOCAL_OUT prio -150
+		chain POSTROUTING hook NF_INET_POST_ROUTING prio -150
+	}
+
+	table filter {
+		chain INPUT hook NF_INET_LOCAL_IN prio 0
+		chain FORWARD hook NF_INET_FORWARD prio 0
+		chain OUTPUT hook NF_INET_LOCAL_OUT prio 0
+	}
+
+	table nat {
+		chain PREROUTING hook NF_INET_PRE_ROUTING prio -100
+		chain INPUT hook NF_INET_LOCAL_IN prio -100
+		chain OUTPUT hook NF_INET_LOCAL_OUT prio 100
+		chain POSTROUTING hook NF_INET_POST_ROUTING prio 100
+	}
+
+	table security {
+		chain INPUT hook NF_INET_LOCAL_IN prio 50
+		chain FORWARD hook NF_INET_FORWARD prio 50
+		chain OUTPUT hook NF_INET_LOCAL_OUT prio 50
 	}
 }