ipv6: support IPV6_PMTU_INTERFACE on sockets

IPV6_PMTU_INTERFACE is the same as IPV6_PMTU_PROBE for ipv6. Add it
nontheless for symmetry with IPv4 sockets. Also drop incoming MTU
information if this mode is enabled.

The additional bit in ipv6_pinfo just eats in the padding behind the
bitfield. There are no changes to the layout of the struct at all.

Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 733747ce163c..c2626ce1f2ad 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -178,10 +178,15 @@ 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) ?
+        return (np && np->pmtudisc >= IPV6_PMTUDISC_PROBE) ?
                skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
 }
 
+static inline bool ip6_sk_accept_pmtu(const struct sock *sk)
+{
+        return inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_INTERFACE;
+}
+
 static inline struct in6_addr *rt6_nexthop(struct rt6_info *rt)
 {
         return &rt->rt6i_gateway;