From e6f8f1a739b652c56e6f959d6714d92e05621e21 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Wed, 8 Aug 2012 21:53:03 +0000 Subject: [PATCH] veth: Allow to create peer link with given ifindex The ifinfomsg is in there (thanks kaber@ for foreseeing this long time ago), so take the given ifidex and register netdev with it. Ben noticed, that this code path previously ignored ifmp->ifi_index and userland could be passing in garbage. Thus it may now fail occasionally because the value clashes with an existing interface. To address this it's assumed that if the caller specifies the ifindex for the veth master device, then it's aware of this possibility and should explicitly specify (or set to 0 for auto-assignment) the peer's ifindex as well. With this the compatibility with old tools not setting ifindex is preserved. Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller --- drivers/net/veth.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 5852361032c4..e522ff70444c 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -348,6 +348,9 @@ static int veth_newlink(struct net *src_net, struct net_device *dev, if (tbp[IFLA_ADDRESS] == NULL) eth_hw_addr_random(peer); + if (ifmp && (dev->ifindex != 0)) + peer->ifindex = ifmp->ifi_index; + err = register_netdevice(peer); put_net(net); net = NULL;