On Fri, Mar 31, 2006 at 09:49:31PM -0500, jamal wrote: > > > > The RFC seems to talk about sender IP address instead though... > > my understanding: the sender is trying to claim that IP and is setting > the destination to the IP it is trying to claim and see if someone > responds.
Are you sure? I read this from Section 2.5: All ARP packets (*replies* as well as requests) that contain a Link- Local 'sender IP address' MUST be sent using link-layer broadcast instead of link-layer unicast. This aids timely detection of duplicate addresses. An example illustrating how this helps is given in Section 4. And Section 4 says: Sending ARP replies that have IPv4 Link-Local sender addresses via broadcast instead of unicast ensures that these conflicts can be detected as soon as they become potential problems, but no sooner. For example, if two disjoint network links are joined, where hosts A and B have both configured the same Link-Local address, X, they can remain in this state until A, B or some other host attempts to initiate communication. If some other host C now sends an ARP request for address X, and hosts A and B were to both reply with conventional unicast ARP replies, then host C might be confused, but A and B still wouldn't know there is a problem because neither would have seen the other's packet. Sending these replies via broadcast allows A and B to see each other's conflicting ARP packets and respond accordingly. So it is clear to me that the idea is that the conflictee will see the broadcast from the conflicter bearing the conflicter's source IP address which is in the 169.254/16 network. The destination IP on the other hand can be anywhere. BTW, I like your idea of moving STP to user-space. In fact I think we can extend it to move ARP to user-space as well. Hopefully when we have proper xfrm resolution queueing it will be a template that we can reuse for all cases where we need user-space help to determine the fate of packet in kernel-space. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <[EMAIL PROTECTED]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
