net: vxlan: use custom ndo_change_mtu handler

When adding a new vxlan device to an "underlying carrier" (here:
dst->remote_ifindex), the MTU size assigned to the vxlan device
is the MTU at setup time of the carrier - needed headroom, when
adding a vxlan device w/o explicit carrier, then it defaults
to 1500.

In case of an explicit carrier that supports jumbo frames, we
currently cannot change vxlan MTU via ip(8) to > 1500 in
post-setup time, as vxlan driver uses eth_change_mtu() as default
method for manually setting MTU.

Hence, use a custom implementation that only falls back to
eth_change_mtu() in case we didn't use a dev parameter on device
setup time, and otherwise allow a max MTU setting of the carrier
incl. adjustment for headroom.

Reported-by: Shahed Shaikh <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Stephen Hemminger <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions