rtnetlink: support specifying device flags on device creation

commit e8469ed959c373c2ff9e6f488aa5a14971aebe1f
Author: Patrick McHardy <kaber@trash.net>
Date:   Tue Feb 23 20:41:30 2010 +0100

Support specifying the initial device flags when creating a device though
rtnl_link. Devices allocated by rtnl_create_link() are marked as INITIALIZING
in order to surpress netlink registration notifications. To complete setup,
rtnl_configure_link() must be called, which performs the device flag changes
and invokes the deferred notifiers if everything went well.

Two examples:

# add macvlan to eth0
#
$ ip link add link eth0 up allmulticast on type macvlan

[LINK]11: macvlan0@eth0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
    link/ether 26:f8:84:02:f9:2a brd ff:ff:ff:ff:ff:ff
[ROUTE]ff00::/8 dev macvlan0  table local  metric 256  mtu 1500 advmss 1440 hoplimit 0
[ROUTE]fe80::/64 dev macvlan0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
[LINK]11: macvlan0@eth0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500
    link/ether 26:f8:84:02:f9:2a
[ADDR]11: macvlan0    inet6 fe80::24f8:84ff:fe02:f92a/64 scope link
       valid_lft forever preferred_lft forever
[ROUTE]local fe80::24f8:84ff:fe02:f92a via :: dev lo  table local  proto none  metric 0  mtu 16436 advmss 16376 hoplimit 0
[ROUTE]default via fe80::215:e9ff:fef0:10f8 dev macvlan0  proto kernel  metric 1024  mtu 1500 advmss 1440 hoplimit 0
[NEIGH]fe80::215:e9ff:fef0:10f8 dev macvlan0 lladdr 00:15:e9:f0:10:f8 router STALE
[ROUTE]2001:6f8:974::/64 dev macvlan0  proto kernel  metric 256  expires 0sec mtu 1500 advmss 1440 hoplimit 0
[PREFIX]prefix 2001:6f8:974::/64 dev macvlan0 onlink autoconf valid 14400 preferred 131084
[ADDR]11: macvlan0    inet6 2001:6f8:974:0:24f8:84ff:fe02:f92a/64 scope global dynamic
       valid_lft 86399sec preferred_lft 14399sec

# add VLAN to eth1, eth1 is down
#
$ ip link add link eth1 up type vlan id 1000
RTNETLINK answers: Network is down

<no events>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 5 deletions

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 35609e6..b583d49 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -333,19 +333,17 @@ static int veth_newlink(struct net *src_net, struct net_device *dev,
 	struct veth_priv *priv;
 	char ifname[IFNAMSIZ];
 	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
+	struct ifinfomsg *ifmp;
 	struct net *net;
 
 	/*
 	 * create and register peer first
-	 *
-	 * struct ifinfomsg is at the head of VETH_INFO_PEER, but we
-	 * skip it since no info from it is useful yet
 	 */
-
 	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
 		struct nlattr *nla_peer;
 
 		nla_peer = data[VETH_INFO_PEER];
+		ifmp = nla_data(nla_peer);
 		err = nla_parse(peer_tb, IFLA_MAX,
 				nla_data(nla_peer) + sizeof(struct ifinfomsg),
 				nla_len(nla_peer) - sizeof(struct ifinfomsg),
@@ -358,8 +356,10 @@ static int veth_newlink(struct net *src_net, struct net_device *dev,
 			return err;
 
 		tbp = peer_tb;
-	} else
+	} else {
+		ifmp = NULL;
 		tbp = tb;
+	}
 
 	if (tbp[IFLA_IFNAME])
 		nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
@@ -387,6 +387,10 @@ static int veth_newlink(struct net *src_net, struct net_device *dev,
 
 	netif_carrier_off(peer);
 
+	err = rtnl_configure_link(peer, ifmp);
+	if (err < 0)
+		goto err_configure_peer;
+
 	/*
 	 * register dev last
 	 *
@@ -428,6 +432,7 @@ static int veth_newlink(struct net *src_net, struct net_device *dev,
 err_register_dev:
 	/* nothing to do */
 err_alloc_name:
+err_configure_peer:
 	unregister_netdevice(peer);
 	return err;