ipv6: Fragment locally generated tunnel-mode IPSec6 packets as needed.

This patch modifies IPsec6 to fragment IPv6 packets that are
locally generated as needed.

This version of the patch only fragments in tunnel mode, so that fragment
headers will not be obscured by ESP in transport mode.

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 278312c..2ab9268 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -164,5 +164,15 @@
 	return rt->rt6i_flags & RTF_LOCAL;
 }
 
+int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
+
+static inline int ip6_skb_dst_mtu(struct sk_buff *skb)
+{
+	struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
+
+	return (np && np->pmtudisc == IPV6_PMTUDISC_PROBE) ?
+	       skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
+}
+
 #endif
 #endif