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Re: Adding of destination options in IPv6

To: jamal <hadi@xxxxxxxxxx>
Subject: Re: Adding of destination options in IPv6
From: Lars Henrik Petander <lpetande@xxxxxxxxxx>
Date: Tue, 11 Jul 2000 16:55:33 +0300 (EET DST)
Cc: Stefan Schlott <stefan.schlott@xxxxxxxxxxxxxxxxxx>, netdev@xxxxxxxxxxx
In-reply-to: <Pine.GSO.4.20.0007110721180.3334-100000@xxxxxxxxxxxxxxxx>
Sender: owner-netdev@xxxxxxxxxxx
On Tue, 11 Jul 2000, jamal wrote:

> 
> 
> On Tue, 11 Jul 2000, Stefan Schlott wrote:
> 
> > *sigh* which is why Lars (and me, too) had to modify the ipv6 module.
> > Passing unfragmented packets to nf6 would be really hard to implement
> > (as far as I understand the code)... but it would be really nice
> > to have an interface which can modify whole packets when sending
> > and receiving; the same thing for forwarding would result in an "always
> > defragment" option, which would be somewhat "un-ip6-ish" :-)
> 
> I might be missing something:
> 
> If you dont want to deal with fragmentation then on input use
> NF_IP6_LOCAL_IN and output NF_IP6_POST_ROUTING

NF_IP6_POST_ROUTING would not necessarily work if the packet already
contained options added by sockets and fragmentation is also done before
it. In order to add the extension headers in the correct order they need
to be inserted into the ip6_txoptions structure before the
ipv6_push_frag_opts or ipv6_push_nfrag_opts functions are called. These
functions add the options into the beginning of the skb in the correct
order.

The incoming options we handled by defining the mobile IPv6 options to 
include/linux/in6.h and adding hooks into net/ipv6/exthdr.c to handle the
options. 

Henrik

> 
> cheers,
> jamal
> 
> 
> 
> 
> 


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