Small patch to multicast code...

[Luigi Rizzo]

On Fri, Aug 29, 2008 at 09:32:10AM -0700, Sam Leffler wrote:
> Luigi Rizzo wrote:
...
> >and to be more explicit - the result of m_pullup is that
> >the number of bytes specified as m_pullup argument are in
> >a private piece of memory -- the 'data' region within the mbuf -- so
> >you can freely play with them without trouble.
> >
> >That is why i suggested to just increase the argument to m_pullup
> >by the size of the udp header so one can overwrite the checksum
> >within the mbuf without touching the shared part in the cluster
> >(if any).
> >  
> 
> Hmm, never considered the m_pullup guaranteed a private copy (but I see 
> it in the code).  The original semantics were just that the data was 
> contiguous.

funny, i thought the guarantee of a writable copy was also part
of the original semantics :)

	cheers
	luigi