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authorDavid Wragg <david@weave.works>2016-06-03 18:58:14 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-06-24 10:18:18 -0700
commit51d7c394605bd5d72e76745def0002dd938ec48b (patch)
tree82399e0cff02fc65f8240bb0fdf611b050f1ee64 /drivers/net
parent3dc443059897b8a2fa3e3b18f794ee31c0063730 (diff)
downloadlinux-rt-51d7c394605bd5d72e76745def0002dd938ec48b.tar.gz
geneve: Relax MTU constraints
[ Upstream commit 55e5bfb53cff286c1c1ff49f51325dc15c7fea63 ] 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 <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/geneve.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index e3f939fef696..240620c5888a 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -994,6 +994,17 @@ 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);
@@ -1038,7 +1049,7 @@ 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,