Date: Sun, 16 May 1999 13:22:05 -0700 From: "Justin C. Walker" <justin@apple.com> To: adrian@freebsd.org Cc: Bernd Walter <ticso@cicely.de>, freebsd-hackers@freebsd.org Subject: Re: ifconfig: changing mac address Message-ID: <199905162022.NAA00766@walker3.apple.com> In-Reply-To: "Your message of Sun, 16 May 1999 11:48:42 %2B0200."<19990516114842.A48820@cicely8.cicely.de>
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> From: adrian@FreeBSD.ORG > Date: 1999-05-16 04:59:51 -0700 > To: Bernd Walter <ticso@cicely.de> > Subject: Re: ifconfig: changing mac address > Cc: freebsd-hackers@FreeBSD.ORG > In-reply-to: "Your message of Sun, 16 May 1999 11:48:42 > +0200."<19990516114842.A48820@cicely8.cicely.de> > Delivered-to: freebsd-hackers@freebsd.org > X-Loop: FreeBSD.ORG > > > >> overloaded for this, no? The driver could fail the request if it > >> didn't support it; or if it has run out of slots for aliases. There > >> should also be (I think) a way to tell the driver to go to > >> promiscuous mode to emulate this (an "I really want this" request?), > >> but I'm not sure it should be the default response to the "set > >> hardware address" request. > > >An alias would be nice. A standby system must be reachable before it > >will be active and will need another MAC to be. > >But I don't see any sence in having more than one MAC on one IP-Address. > >So talking on IP it should be an optional argument to the ip-alias. > > Remembering that if you add multiple hw addresses to a single card, you then > have to lock down IP addresses to hw addresses or things become very > very very confused. > > Can someone with a little more experience in the IP/arp code explain this > one a bit better? I'm just waving my hands here, but first, I think drivers should be able to provide this "service" without getting too hung up in the implications (i.e., they just pass incoming data up the line and let another piece of the system deal with it; and for output, they take fully-formed packets and get the bits on the wire [I did say I was hand-waving]). I think the upper layers might be able to keep this stuff straight, e.g., by providing virtual interfaces above the physical, to discriminate on physical addresses. Also, this isn't IP-specific, since the Mac makes use of this capability for support of "other OSs and their [unprintable] stacks" (this in response to the concern that about more than one MAC address per IP address). Being able to use this functionality may take a bit more engineering, but it seems that there is good reason to consider it as part of the "driver interface". Regards, Justin -- Justin C. Walker, Curmudgeon-At-Large * Institute for General Semantics | Manager, CoreOS Networking | Men are from Earth. Apple Computer, Inc. | Women are from Earth. 2 Infinite Loop | Deal with it. Cupertino, CA 95014 | *-------------------------------------*-------------------------------* To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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