tree 4871d69274a682be6379696208efafc622d3234d
parent e86663c475d384ab5f46cb5637e9b7ad08c5c505
author Paolo Abeni <pabeni@redhat.com> 1468512010 +0200
committer David S. Miller <davem@davemloft.net> 1468725302 -0700

vlan: use a valid default mtu value for vlan over macsec

macsec can't cope with mtu frames which need vlan tag insertion, and
vlan device set the default mtu equal to the underlying dev's one.
By default vlan over macsec devices use invalid mtu, dropping
all the large packets.
This patch adds a netif helper to check if an upper vlan device
needs mtu reduction. The helper is used during vlan devices
initialization to set a valid default and during mtu updating to
forbid invalid, too bit, mtu values.
The helper currently only check if the lower dev is a macsec device,
if we get more users, we need to update only the helper (possibly
reserving an additional IFF bit).

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>