ip6_tunnel: allow ip6gre dev mtu to be set below 1280

[ Upstream commit 2fa771be953a17f8e0a9c39103464c2574444c62 ]

Commit 582442d6d5bc ("ipv6: Allow the MTU of ipip6 tunnel to be set
below 1280") fixed a mtu setting issue. It works for ipip6 tunnel.

But ip6gre dev updates the mtu also with ip6_tnl_change_mtu. Since
the inner packet over ip6gre can be ipv4 and it's mtu should also
be allowed to set below 1280, the same issue also exists on ip6gre.

This patch is to fix it by simply changing to check if parms.proto
is IPPROTO_IPV6 in ip6_tnl_change_mtu instead, to make ip6gre to
go to 'else' branch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Xin Long 2017-12-25 14:45:12 +08:00 committed by Greg Kroah-Hartman
parent d4727e485a
commit 4132ec3527

View File

@ -1684,11 +1684,11 @@ int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
{
struct ip6_tnl *tnl = netdev_priv(dev);
if (tnl->parms.proto == IPPROTO_IPIP) {
if (new_mtu < ETH_MIN_MTU)
if (tnl->parms.proto == IPPROTO_IPV6) {
if (new_mtu < IPV6_MIN_MTU)
return -EINVAL;
} else {
if (new_mtu < IPV6_MIN_MTU)
if (new_mtu < ETH_MIN_MTU)
return -EINVAL;
}
if (new_mtu > 0xFFF8 - dev->hard_header_len)