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>

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 35609e6..b583d49 100644 (file)
--- 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;
 

diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index 48d3efc..af60fd0 100644 (file)
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -87,6 +87,8 @@ extern void   rtnl_link_unregister(struct rtnl_link_ops *ops);
 extern struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]);
 extern struct net_device *rtnl_create_link(struct net *src_net, struct net *net,
        char *ifname, const struct rtnl_link_ops *ops, struct nlattr *tb[]);
+extern int rtnl_configure_link(struct net_device *dev,
+                              const struct ifinfomsg *ifm);
 extern const struct nla_policy ifla_policy[IFLA_MAX+1];
 
 #define MODULE_ALIAS_RTNL_LINK(kind) MODULE_ALIAS("rtnl-link-" kind)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index c21ec42..d1472a4 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -549,6 +549,19 @@ static void set_operstate(struct net_device *dev, unsigned char transition)
        }
 }
 
+static unsigned int rtnl_dev_combine_flags(const struct net_device *dev,
+                                          const struct ifinfomsg *ifm)
+{
+       unsigned int flags = ifm->ifi_flags;
+
+       /* bugwards compatibility: ifi_change == 0 is treated as ~0 */
+       if (ifm->ifi_change)
+               flags = (flags & ifm->ifi_change) |
+                       (dev->flags & ~ifm->ifi_change);
+
+       return flags;
+}
+
 static void copy_rtnl_link_stats(struct rtnl_link_stats *a,
                                 const struct net_device_stats *b)
 {
@@ -904,13 +917,7 @@ static int do_setlink(struct net_device *dev, struct ifinfomsg *ifm,
        }
 
        if (ifm->ifi_flags || ifm->ifi_change) {
-               unsigned int flags = ifm->ifi_flags;
-
-               /* bugwards compatibility: ifi_change == 0 is treated as ~0 */
-               if (ifm->ifi_change)
-                       flags = (flags & ifm->ifi_change) |
-                               (dev->flags & ~ifm->ifi_change);
-               err = dev_change_flags(dev, flags);
+               err = dev_change_flags(dev, rtnl_dev_combine_flags(dev, ifm));
                if (err < 0)
                        goto errout;
        }
@@ -1053,6 +1060,26 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
        return 0;
 }
 
+int rtnl_configure_link(struct net_device *dev, const struct ifinfomsg *ifm)
+{
+       unsigned int old_flags;
+       int err;
+
+       old_flags = dev->flags;
+       if (ifm && (ifm->ifi_flags || ifm->ifi_change)) {
+               err = __dev_change_flags(dev, rtnl_dev_combine_flags(dev, ifm));
+               if (err < 0)
+                       return err;
+       }
+
+       dev->rtnl_link_state = RTNL_LINK_INITIALIZED;
+       rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U);
+
+       __dev_notify_flags(dev, old_flags);
+       return 0;
+}
+EXPORT_SYMBOL(rtnl_configure_link);
+
 struct net_device *rtnl_create_link(struct net *src_net, struct net *net,
        char *ifname, const struct rtnl_link_ops *ops, struct nlattr *tb[])
 {
@@ -1074,6 +1101,7 @@ struct net_device *rtnl_create_link(struct net *src_net, struct net *net,
 
        dev_net_set(dev, net);
        dev->rtnl_link_ops = ops;
+       dev->rtnl_link_state = RTNL_LINK_INITIALIZING;
        dev->real_num_tx_queues = real_num_queues;
 
        if (strchr(dev->name, '%')) {
@@ -1203,7 +1231,7 @@ replay:
                if (!(nlh->nlmsg_flags & NLM_F_CREATE))
                        return -ENODEV;
 
-               if (ifm->ifi_index || ifm->ifi_flags || ifm->ifi_change)
+               if (ifm->ifi_index)
                        return -EOPNOTSUPP;
                if (tb[IFLA_MAP] || tb[IFLA_MASTER] || tb[IFLA_PROTINFO])
                        return -EOPNOTSUPP;
@@ -1234,9 +1262,15 @@ replay:
                        err = ops->newlink(net, dev, tb, data);
                else
                        err = register_netdevice(dev);
-               if (err < 0 && !IS_ERR(dev))
+               if (err < 0 && !IS_ERR(dev)) {
                        free_netdev(dev);
+                       goto out;
+               }
 
+               err = rtnl_configure_link(dev, ifm);
+               if (err < 0)
+                       unregister_netdevice(dev);
+out:
                put_net(dest_net);
                return err;
        }