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authorJakub Sitnicki <jkbs@redhat.com>2017-01-13 10:12:20 +0100
committerDavid S. Miller <davem@davemloft.net>2017-01-16 13:22:12 -0500
commit02ca0423fd65a0a9c4d70da0dbb8f4b8503f08c7 (patch)
tree92f2d3c0716e4c8e2b2990d57a34bd68bbfddc7f /net
parent1666d49e1d416fcc2cce708242a52fe3317ea8ba (diff)
ip6_tunnel: Account for tunnel header in tunnel MTU
With ip6gre we have a tunnel header which also makes the tunnel MTU smaller. We need to reserve room for it. Previously we were using up space reserved for the Tunnel Encapsulation Limit option header (RFC 2473). Also, after commit b05229f44228 ("gre6: Cleanup GREv6 transmit path, call common GRE functions") our contract with the caller has changed. Now we check if the packet length exceeds the tunnel MTU after the tunnel header has been pushed, unlike before. This is reflected in the check where we look at the packet length minus the size of the tunnel header, which is already accounted for in tunnel MTU. Fixes: b05229f44228 ("gre6: Cleanup GREv6 transmit path, call common GRE functions") Signed-off-by: Jakub Sitnicki <jkbs@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/ip6_tunnel.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 36d292180942..753d6d0860fb 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1108,7 +1108,7 @@ route_lookup:
t->parms.name);
goto tx_err_dst_release;
}
- mtu = dst_mtu(dst) - psh_hlen;
+ mtu = dst_mtu(dst) - psh_hlen - t->tun_hlen;
if (encap_limit >= 0) {
max_headroom += 8;
mtu -= 8;
@@ -1117,7 +1117,7 @@ route_lookup:
mtu = IPV6_MIN_MTU;
if (skb_dst(skb) && !t->parms.collect_md)
skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
- if (skb->len > mtu && !skb_is_gso(skb)) {
+ if (skb->len - t->tun_hlen > mtu && !skb_is_gso(skb)) {
*pmtu = mtu;
err = -EMSGSIZE;
goto tx_err_dst_release;