veth: set peer GSO values

[ Upstream commit 72d24955 ]

When new veth is created, and GSO values have been configured
on one device, clone those values to the peer.

For example:
   # ip link add dev vm1 gso_max_size 65530 type veth peer name vm2

This should create vm1 <--> vm2 with both having GSO maximum
size set to 65530.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/veth.c

@@ -399,6 +399,9 @@ static int veth_newlink(struct net *src_net, struct net_device *dev,
 	if (ifmp && (dev->ifindex != 0))
 		peer->ifindex = ifmp->ifi_index;
 
+	peer->gso_max_size = dev->gso_max_size;
+	peer->gso_max_segs = dev->gso_max_segs;
+
 	err = register_netdevice(peer);
 	put_net(net);
 	net = NULL;