On 02/09/2016 07:47 PM, David Wragg wrote:
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 | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 0b14ac3..05cef11 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1039,6 +1039,16 @@ 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. */
The networking code formats comments:
/* Like
* this.
*/
+ 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);
[...]
MBR, Sergei
