[RTNETLINK]: Allow changing of subsets of netdevice flags in rtnl_setlink

rtnl_setlink doesn't allow to change subsets of the flags, just to override
the set entirely by a new one. This means that for simply setting a device
up or down userspace first needs to query the current flags, change it and
send the changed flags back, which is racy and needlessly complicated.

Mask the flags using ifi_change since this is what it is intended for.
For backwards compatibility treat ifi_change == 0 as ~0 (even though it
seems quite unlikely that anyone has been using this so far).

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2007-05-22 17:00:01 -07:00 committed by David S. Miller
parent 1f8481d19a
commit 83b496e928

View file

@ -689,8 +689,15 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
}
if (ifm->ifi_flags)
dev_change_flags(dev, ifm->ifi_flags);
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);
dev_change_flags(dev, flags);
}
if (tb[IFLA_TXQLEN])
dev->tx_queue_len = nla_get_u32(tb[IFLA_TXQLEN]);