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Re: [PATCH][IPv6] separation xfrm_lookup from ip6_dst_lookup

To: Kazunori Miyazawa <kazunori@xxxxxxxxxxxx>
Subject: Re: [PATCH][IPv6] separation xfrm_lookup from ip6_dst_lookup
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 2 Aug 2004 17:41:47 +1000
Cc: davem@xxxxxxxxxx, netdev@xxxxxxxxxxx, usagi-core@xxxxxxxxxxxxxx, Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>
In-reply-to: <20040730171205.114f22ba.kazunori@xxxxxxxxxxxx>
References: <20040730171205.114f22ba.kazunori@xxxxxxxxxxxx>
Sender: netdev-bounce@xxxxxxxxxxx
User-agent: Mutt/1.5.6+20040523i
On Fri, Jul 30, 2004 at 05:12:05PM +0900, Kazunori Miyazawa wrote:
> 
> This patch separates xfrm_lookup from ip6_dst_lookup
> to support srcrt correctly. ip6_dst_lookup should be
> called with next hop. however xfrm_lookup should be
> called with final destination. It fixes them.

Thanks for the patch.

This raises an interesting question.  Is it really correct to look at
the first hop address when doing the route lookup?

The problem is that if we use the first-hop address as the dst when
doing the route lookup then we may end up with incorrect MTU information.
This is because the MTU to the final destination may well be smaller than
the MTU to the first hop.

It seems that Alexey thought about this six years ago according to
the rthdr comment in icmpv6_rcv().

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
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