From: David Wragg <david@weave.works>
Upstream commit:
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>
Signed-off-by: David S. Miller <da...@davemloft.net>
Upstream: 55e5bfb53cff ("geneve: Relax MTU constraints")
Signed-off-by: Joe Stringer <j...@ovn.org>
---
datapath/linux/compat/geneve.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/datapath/linux/compat/geneve.c b/datapath/linux/compat/geneve.c
index 297593ce6e1a..29a65a0a49d2 100644
--- a/datapath/linux/compat/geneve.c
+++ b/datapath/linux/compat/geneve.c
@@ -742,6 +742,17 @@ static netdev_tx_t geneve_dev_xmit(struct sk_buff *skb,
struct net_device *dev)
return NETDEV_TX_OK;
}
+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 const struct net_device_ops geneve_netdev_ops = {
#ifdef HAVE_DEV_TSTATS
.ndo_init = geneve_init,
@@ -751,7 +762,7 @@ static const struct net_device_ops geneve_netdev_ops = {
.ndo_open = geneve_open,
.ndo_stop = geneve_stop,
.ndo_start_xmit = geneve_dev_xmit,
- .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,
};
--
2.1.4
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