[PATCH net v3 2/3] geneve: Relax MTU constraints
From: David Wragg <hidden>
Date: 2016-02-10 00:05:57
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted> --- drivers/net/geneve.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 0b14ac3..d2031ce 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c@@ -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,
--
2.5.0
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