[PATCH net v2 1/3] vxlan: Relax the MTU constraints
From: David Wragg <hidden>
Date: 2016-02-10 00:05:56
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2016-02-09 · [PATCH net v2 1/3] vxlan: Relax the MTU constraints · David Wragg <hidden>
Allow the MTU of vxlan devices without an underlying device to be set to larger values (up to a maximum based on IP packet limits and vxlan overhead). Previously, their MTUs could not be set to higher than the conventional ethernet value of 1500. This is a very arbitrary value in the context of vxlan, and prevented vxlan devices from being able to take advantage of jumbo frames etc. The default MTU remains 1500, for compatibility. Signed-off-by: David Wragg <redacted> Acked-by: Roopa Prabhu <redacted> --- drivers/net/vxlan.c | 36 +++++++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 11 deletions(-)
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 6543918..e992c6a 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c@@ -2367,29 +2367,43 @@ static void vxlan_set_multicast_list(struct net_device *dev) { } -static int vxlan_change_mtu(struct net_device *dev, int new_mtu) +static int __vxlan_change_mtu(struct net_device *dev, + struct net_device *lowerdev, + struct vxlan_rdst *dst, int new_mtu, bool strict) { - struct vxlan_dev *vxlan = netdev_priv(dev); - struct vxlan_rdst *dst = &vxlan->default_dst; - struct net_device *lowerdev; - int max_mtu; + int max_mtu = IP_MAX_MTU; - lowerdev = __dev_get_by_index(vxlan->net, dst->remote_ifindex); - if (lowerdev == NULL) - return eth_change_mtu(dev, new_mtu); + if (lowerdev) + max_mtu = lowerdev->mtu; if (dst->remote_ip.sa.sa_family == AF_INET6) - max_mtu = lowerdev->mtu - VXLAN6_HEADROOM; + max_mtu -= VXLAN6_HEADROOM; else - max_mtu = lowerdev->mtu - VXLAN_HEADROOM; + max_mtu -= VXLAN_HEADROOM; - if (new_mtu < 68 || new_mtu > max_mtu) + if (new_mtu < 68) return -EINVAL; + if (new_mtu > max_mtu) { + if (strict) + return -EINVAL; + + new_mtu = max_mtu; + } + dev->mtu = new_mtu; return 0; } +static int vxlan_change_mtu(struct net_device *dev, int new_mtu) +{ + struct vxlan_dev *vxlan = netdev_priv(dev); + struct vxlan_rdst *dst = &vxlan->default_dst; + struct net_device *lowerdev = __dev_get_by_index(vxlan->net, + dst->remote_ifindex); + return __vxlan_change_mtu(dev, lowerdev, dst, new_mtu, true); +} + static int egress_ipv4_tun_info(struct net_device *dev, struct sk_buff *skb, struct ip_tunnel_info *info, __be16 sport, __be16 dport)
--
2.5.0
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