ip6gretap: Fix MTU to allow for Ethernet header
When we were creating an ip6gretap interface the MTU was about 6 bytes
short of what was needed. It turns out we were not taking the Ethernet
header into account and as a result we were eating into the 8 bytes
reserved for the encap limit.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 4e636e6..2be66e7 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -987,6 +987,8 @@
dev->mtu = rt->dst.dev->mtu - addend;
if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
dev->mtu -= 8;
+ if (dev->type == ARPHRD_ETHER)
+ dev->mtu -= ETH_HLEN;
if (dev->mtu < IPV6_MIN_MTU)
dev->mtu = IPV6_MIN_MTU;