Date: Sat, 12 Dec 1998 20:43:59 +0100 From: Poul-Henning Kamp <phk@FreeBSD.ORG> To: arch@FreeBSD.ORG Subject: IFF_UP, IFF_RUNNING semantics... Message-ID: <8240.913491839@critter.freebsd.dk>
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I'm trying to unravel how IFF_UP and IFF_RUNNING is supposed to work. I would expect one of them (IFF_RUNNING ?) to mean "should be running" as in "root configured this one to be running" and the other (IFF_UP ?) to mean "is running" as in "hardware/protocols are ready to pass packets". In this model, IFF_UP would control the routes. Either by yanking the route when IFF_UP disappears, or by not selecting routes where the interface doesn't have IFF_UP set. Looking over the sources, it is obvious that very few people if any have any idea about the semantics about IFF_UP and IFF_RUNNING either. For an example why this is important imagine an UTP ethernet which doesn't receive a heartbeat. In that case the hardware knows the interface is down and the route should be disabled so the packets could attempt to flow another way. Words of wisdom on the subject kindly solicited. -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." "ttyv0" -- What UNIX calls a $20K state-of-the-art, 3D, hi-res color terminal To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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