From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Subject: Re: [PATCH net-next v5] IPv6: add the option to use anycast addresses as source addresses in echo reply
Date: Wed, 8 Jan 2014 00:39:29 +0100
Message-ID: <20140107233929.GN30393@order.stressinduktion.org>
References: <1389103047-3380-1-git-send-email-fx.lebail@yahoo.com> <20140107175507.fb543c70.billfink@mindspring.com> <20140107.183305.1907441201345858474.davem@davemloft.net>
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To: David Miller <davem@davemloft.net>
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On Tue, Jan 07, 2014 at 06:33:05PM -0500, David Miller wrote:
> From: Bill Fink <billfink@mindspring.com>
> Date: Tue, 7 Jan 2014 17:55:07 -0500
> 
> > Why is ICMPV6 Echo Reply special?  Can't the internal structure
> > of the network be divined from other ICMPv6 responses such as
> > Destination Unreachable, Time Exceeded (Hop Limit), and Parameter
> > Problem.
> 
> Right, this RFC is talking about source address selection in general,
> so this anycast handling should be in a generic place too.

I think it would be reasonable to change future behavior to always
send back icmp errors with the anycast address (same as original packet
destination). Ping is a bit special as it is used for service discovery.

UDP sockets can use their source address at will. So I still think this change
is reasonable.