rev. 1.94 of netinet/in.c broke CARP

[Gleb Smirnoff]

On Thu, Jan 25, 2007 at 08:40:52PM +0000, Robert Watson wrote:
R> Architecturally, the right fix is that CARP needs to have a handler for 
R> ifnet destruction that always runs before the multicast address garbage 
R> collection. I'm pretty preoccupied for the next few days due to an 
R> impending paper deadline, so can't investigate further currently, but one 
R> way or the other that ordering dependency needs to be expressed.  If done 
R> properly, CARP will always have released its multicast address before they 
R> are forceably removed. Having the reference count is good too, but what I 
R> describe should be sufficient regardless of the refcount.

This means removing usage of EVENTHANDLER(9) and going back to
exporting carp_ifdetach() and calling it directly from if_detach().
This is back out revision 1.255 of net/if.c. Not sure what is a right
way...

I am worried about that CARP is not the only subsystem in kernel
that can join a multicast group on an ifnet, and keep a pointer
to the multicast instance.

-- 
Totus tuus, Glebius.
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