From: David Wragg Date: Wed, 10 Feb 2016 00:05:57 +0000 (+0000) Subject: datapath: geneve: Relax MTU constraints. X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Fovs.git;a=commitdiff_plain;h=ef1d4fc0dde112418d97ae93dee419fc8db0eeaa datapath: geneve: Relax MTU constraints. 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 Signed-off-by: David S. Miller Upstream: 55e5bfb53cff ("geneve: Relax MTU constraints") Signed-off-by: Joe Stringer Acked-by: Jesse Gross --- diff --git a/datapath/linux/compat/geneve.c b/datapath/linux/compat/geneve.c index 297593ce6..29a65a0a4 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, };