Commit e6f8f1a7 authored Aug 08, 2012 by Pavel Emelyanov Committed by David S. Miller Aug 09, 2012

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 <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 9c7dafbf

drivers/net/veth.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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;

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