@@ -1039,6 +1039,17 @@ static netdev_tx_t geneve_xmit(struct sk_buff *skb, struct net_device *dev)
return geneve_xmit_skb(skb, dev, info);
}
+static int geneve_change_mtu(struct net_device *dev, int new_mtu)
+{
+ /* GENEVE overhead is not fixed, so we can't enforce a more
+ * precise max MTU.
+ */
+ if (new_mtu < 68 || new_mtu > IP_MAX_MTU)
+ return -EINVAL;
+ dev->mtu = new_mtu;
+ return 0;
+}
+
static int geneve_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
{
struct ip_tunnel_info *info = skb_tunnel_info(skb);
@@ -1083,7 +1094,7 @@ static const struct net_device_ops geneve_netdev_ops = {
.ndo_stop = geneve_stop,
.ndo_start_xmit = geneve_xmit,
.ndo_get_stats64 = ip_tunnel_get_stats64,
- .ndo_change_mtu = eth_change_mtu,
+ .ndo_change_mtu = geneve_change_mtu,
.ndo_validate_addr = eth_validate_addr,
.ndo_set_mac_address = eth_mac_addr,
.ndo_fill_metadata_dst = geneve_fill_metadata_dst,
Allow the MTU of geneve devices to be set to large values, in order to exploit underlying networks with larger frame sizes. GENEVE does not have a fixed encapsulation overhead (an openvswitch rule can add variable length options), so there is no relevant maximum MTU to enforce. A maximum of IP_MAX_MTU is used instead. Encapsulated packets that are too big for the underlying network will get dropped on the floor. Signed-off-by: David Wragg <david@weave.works> --- drivers/net/geneve.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)