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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 <shahed.shaikh@qlogic.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Daniel Borkmann 2013-12-18 00:21:08 +01:00 committed by David S. Miller
parent 289dccbe14
commit 345010b5c4
1 changed files with 24 additions and 1 deletions
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25
drivers/net/vxlan.c
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@ -2014,6 +2014,29 @@ static void vxlan_set_multicast_list(struct net_device *dev)
{
}
static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
{
struct vxlan_dev *vxlan = netdev_priv(dev);
struct vxlan_rdst *dst = &vxlan->default_dst;
struct net_device *lowerdev;
int max_mtu;
lowerdev = __dev_get_by_index(dev_net(dev), dst->remote_ifindex);
if (lowerdev == NULL)
return eth_change_mtu(dev, new_mtu);
if (dst->remote_ip.sa.sa_family == AF_INET6)
max_mtu = lowerdev->mtu - VXLAN6_HEADROOM;
else
max_mtu = lowerdev->mtu - VXLAN_HEADROOM;
if (new_mtu < 68 || new_mtu > max_mtu)
return -EINVAL;
dev->mtu = new_mtu;
return 0;
}
static const struct net_device_ops vxlan_netdev_ops = {
.ndo_init = vxlan_init,
.ndo_uninit = vxlan_uninit,
@ -2022,7 +2045,7 @@ static const struct net_device_ops vxlan_netdev_ops = {
.ndo_start_xmit = vxlan_xmit,
.ndo_get_stats64 = ip_tunnel_get_stats64,
.ndo_set_rx_mode = vxlan_set_multicast_list,
.ndo_change_mtu = eth_change_mtu,
.ndo_change_mtu = vxlan_change_mtu,
.ndo_validate_addr = eth_validate_addr,
.ndo_set_mac_address = eth_mac_addr,
.ndo_fdb_add = vxlan_fdb_add,