Date: Fri, 10 Aug 2007 13:00:11 GMT From: Bruce M Simpson <bms@incunabulum.net> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/111493: routed doesn't use multicasts for RIPv2 via P2P interfaces Message-ID: <200708101300.l7AD0BVe010892@freefall.freebsd.org>
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The following reply was made to PR bin/111493; it has been noted by GNATS. From: Bruce M Simpson <bms@incunabulum.net> To: James Carlson <carlsonj@workingcode.com> Cc: Vernon Schryver <vjs@calcite.rhyolite.com>, dan@obluda.cz, freebsd-gnats-submit@FreeBSD.org Subject: Re: bin/111493: routed doesn't use multicasts for RIPv2 via P2P interfaces Date: Fri, 10 Aug 2007 13:54:18 +0100 James Carlson wrote: > Vernon Schryver writes: > >> What do you think of the enclose patch? It differs from the original >> in two ways that should reduce behavior changes seen by people with >> IFF_POINTOPOINT interfaces without IFF_MULTICAST. If it makes sense, >> I'll generate a bundle on http://www.rhyolite.com/src/ >> > > It seems reasonable to me for RIP. Looking at the code, it seems that > rdisc already handles this case -- despite the comment to the contrary > on send_adv's and send_rdisc's 'dst' argument, the value can be a > multicast destination (not just 0 or unicast), and often is. > > +1 here. It is OK to allow the use of multicast addressing on links which do not natively multicast. Indeed it is necessary for IPv4 and IPv6 multicast forwarding to work across generic point-to-point links, as no special encapsulation is performed. RIPv2's multicast address falls in the 224.0.0.0/8 link local scope, so it should never be seen outside of the link anyway. I would just suggest that it should default to off to avoid confusing folk. If Zebra/Quagga is disallowing multicasted RIP across non-multicast links, that's another story entirely. Regards, BMS
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