xfrm: introduce helper for safe determination of mtu
skb->sk socket can be of AF_INET or AF_INET6 address family. Thus we
always have to make sure we a referring to the correct interpretation
of skb->sk.
We only depend on header defines to query the mtu, so we don't introduce
a new dependency to ipv6 by this change.
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index b64fff3..3ac5ab2 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -138,7 +138,10 @@
{
struct dst_entry *dst = skb_dst(skb);
struct xfrm_state *x = dst->xfrm;
- int mtu = ip6_skb_dst_mtu(skb);
+ int mtu = xfrm_skb_dst_mtu(skb);
+
+ if (mtu < IPV6_MIN_MTU)
+ mtu = IPV6_MIN_MTU;
if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
xfrm6_local_rxpmtu(skb, mtu);