Hi,

attached you find a patch against Linux 2.4.18ac2 that revives the
IFF_RUNNING flag in the dev->flags element. Some time ago, Alexey has
replaced IFF_RUNNING by a bit in dev->state, AFAIK because of locking
reasons.

When enabled, a thread is compiled into the kernel that scans the
network device list on every netif_carrier_on()/_off() called by a
device driver and mirrors the !LINK_STATE_NOCARRIER bit of dev->state
into IFF_RUNNING. If these values differ for a device, a netlink message
is broadcasted. This allows user processes to be notified about
operative state changes. Actually, I've written some patches for the
zebra routing daemon so that it stops using an interface while the
driver thinks that it is down.

The thread worked fine for me as a once-per-second polling module for
several weeks, and I hope I've found all gotchas to make it a "real"
part of the kernel. There are problems left with obsolete drivers that
are still playing with IFF_RUNNING directly, so I don't think this stuff
is ready for the official 2.4 tree. Anyway, I'd like to have some
testers and of course feedback.

Alan, please consider applying to your -ac tree.

Cheers, Stefan