Subject: Re: [2.4 PATCH] bugfix: ARP respond on all devices

From: Steven Blake <[email-masked]>
Date: 20 Aug 2003 00:58:07 -0400

On Tue, 2003-08-19 at 13:53, David S. Miller wrote:

> BTW, this ARP source address algorithm we use comes from
> ipv6, it would be instructive to go and see why they do
> things the way they do.

Are you sure?  See below:

========================================================================

RFC 2461              Neighbor Discovery for IPv6          December 1998

4.3.  Neighbor Solicitation Message Format

   Nodes send Neighbor Solicitations to request the link-layer address
   of a target node while also providing their own link-layer address to
   the target.  Neighbor Solicitations are multicast when the node needs
   to resolve an address and unicast when the node seeks to verify the
   reachability of a neighbor.

         0                   1                   2                   3
         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |     Type      |     Code      |          Checksum             |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                           Reserved                            |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                                                               |
        +                                                               +
        |                                                               |
        +                       Target Address                          +
        |                                                               |
        +                                                               +
        |                                                               |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |   Options ...
        +-+-+-+-+-+-+-+-+-+-+-+-

   IP Fields:

      Source Address
                     Either an address assigned to the interface from
                     which this message is sent or (if Duplicate Address
                     Detection is in progress [ADDRCONF]) the
                     unspecified address.

      Destination Address
                     Either the solicited-node multicast address
                     corresponding to the target address, or the target
                     address.

      Hop Limit      255

      Authentication Header
                     If a Security Association for the IP Authentication
                     Header exists between the sender and the
                     destination address, then the sender SHOULD include
                     this header.

Narten, et. al.             Standards Track                    [Page 21]

========================================================================

Regards,

// Steve