[Olsr-dev] mtu problem with multicast ipv6 packets

John Hay (spam-protected)
Sun Oct 19 23:22:42 CEST 2008

On Sun, Oct 19, 2008 at 10:51:02PM +0200, Bernd Petrovitsch wrote:
> Hi!
> On Son, 2008-10-19 at 21:30 +0200, John Hay wrote:
> [...]
> > So here is my patch to clip the mtu in the IPv6 case. I have hardcoded
> > OLSR_IPV6_MTU, but at least on the BSDs it is defined in netinet/ip6.h as
> > IPV6_MMTU. It did not look as if ip6.h is pulled in at the moment, so I did
> > not know if we should start now. :-)
> Why not?

Well looking through interfaces.h and defs.h, it seemed to hardcode
some of the network related values, so I was not sure which way to
go. Also I wasn't sure if it was a standard define in a standard
place. I found quite a few BSD references, but not much else.

> Is there any reason not to use a #define in a system header and hardcode
> magic values in some application?
> Hmm, on my Fedora-9, I can find
> ----  snip  ----
> /* The latest drafts declared increase in minimal mtu up to 1280. */
> #define IPV6_MIN_MTU	1280
> ----  snip  ----
> in <linux/ipv6.h> which seems to be the equivalent value.

Ok, so linux use a different define in a different file, OSX will
probably be like the BSDs, so that leaves Windows... What else is
there to worry about?

John Hay -- (spam-protected) / (spam-protected)

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