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    SubjectRe: IFF_UP vs IFF_RUNNING

    On Fri, 9 Jul 1999, Jan Kasprzak wrote:

    > Hello,
    > what is the difference between the IFF_UP and IFF_RUNNING?
    > I have looked into the ifconfig's source, and the "ifconfig up" command
    > sets both the IFF_UP and IFF_RUNNING flags, while the "ifconfig down"
    > clears the IFF_UP only. This can mean that the IFF_UP is for
    > "administrative status" of an interface (i.e. system administrator
    > want the interface to be active), and the IFF_RUNNING is the
    > "operative status" (in Cis*o terminology) - the line protocol
    > (keepalive/linefill, linkbeat) on the interface is running.
    > Am I right with this guess? If so, then I think the
    > drivers/net/syncppp.c uses these two flags in the opposite sense:
    > The code around line 530 is the following:
    > if (! (dev->flags & IFF_UP) &&
    > (dev->flags & IFF_RUNNING)) {
    > /* Coming out of loopback mode. */
    > dev->flags |= IFF_UP;
    > printk (KERN_INFO "%s: up\n", dev->name);
    > I think device driver should never set the administrative
    > status (IFF_UP) itself, but can set the operative status (IFF_RUNNING),
    > if the line become OK (e.g. it gets correct LCP or keepalive packet).

    I have already fixed the syncppp driver (and dev.c to keep IFF_RUNNING
    consistent) when integrating the comx drivers. You can download the full
    patch from


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