From mboxrd@z Thu Jan 1 00:00:00 1970 From: kuznet@ms2.inr.ac.ru Subject: Re: [PATCH] IPv6: Fix broken anycast usage Date: Tue, 15 Jul 2003 04:29:44 +0400 (MSD) Sender: netdev-bounce@oss.sgi.com Message-ID: <200307150029.EAA06610@dub.inr.ac.ru> References: <1057997590.1142.31.camel@hades> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@oss.sgi.com Return-path: To: mika.liljeberg@welho.COM (Mika Liljeberg) In-Reply-To: <1057997590.1142.31.camel@hades> from "Mika Liljeberg" at éÀÌ 12, 2003 12:45:01 Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Hello! > this doesn't need to be policed. In general, there is no reliable way to > check if a remote address is anycast, anyway. From RFC2461: > > Note that an anycast address is syntactically > indistinguishable from a unicast address. This is right. (Well, except for the fact that reserved anycasts are very well syntactically distinguished. :-)) But this does not matter, the patch is correct, ANYCAST is an additional attribute on unicast addresses and it should be checked only in contexts where _this_ host is a member of this anycast. BTW it is an addendum to my previous mail. You were right complaining about EINVAL for anycast nexthop. However: Nexthop address is unique identifier of nexthop router. We do not enforce this policy (see comments in route.c), hence it is bug to reject such routes and you are right, but this does not make your example more reasonable. Any non-unicast non-linklocal address used as nexthop is bad idea, this policy is not enforced to allow use of global nexthops on BGP routers, where it is convenient to use global addresses for nexthop resolution and where it is legal because they are not expected to receive redirects This is legal in your case of PtP link too, however, this is still nasty. Alexey