netfilter: ip6t_REJECT: added missing icmpv6 codes

RFC 4443 added two new codes values for ICMPv6 type 1:

 5 - Source address failed ingress/egress policy
 6 - Reject route to destination

And RFC 7084 states in L-14 that IPv6 Router MUST send ICMPv6 Destination
Unreachable with code 5 for packets forwarded to it that use an address
from a prefix that has been invalidated.

Codes 5 and 6 are more informative subsets of code 1.
Signed-off-by: NAndreas Herz <andi@geekosphere.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

include/uapi/linux/netfilter_ipv6/ip6t_REJECT.h

@@ -10,7 +10,9 @@ enum ip6t_reject_with {
 	IP6T_ICMP6_ADDR_UNREACH,
 	IP6T_ICMP6_PORT_UNREACH,
 	IP6T_ICMP6_ECHOREPLY,
-	IP6T_TCP_RESET
+	IP6T_TCP_RESET,
+	IP6T_ICMP6_POLICY_FAIL,
+	IP6T_ICMP6_REJECT_ROUTE
 };
 
 struct ip6t_reject_info {

net/ipv6/netfilter/ip6t_REJECT.c

@@ -63,6 +63,12 @@ reject_tg6(struct sk_buff *skb, const struct xt_action_param *par)
 	case IP6T_TCP_RESET:
 		nf_send_reset6(net, skb, par->hooknum);
 		break;
+	case IP6T_ICMP6_POLICY_FAIL:
+		nf_send_unreach6(net, skb, ICMPV6_POLICY_FAIL, par->hooknum);
+		break;
+	case IP6T_ICMP6_REJECT_ROUTE:
+		nf_send_unreach6(net, skb, ICMPV6_REJECT_ROUTE, par->hooknum);
+		break;
 	}
 
 	return NF_DROP;