Subject: Re: kern/3508 bug: cached ip route and interface up/down.
To: None <firstname.lastname@example.org, email@example.com>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
Date: 11/19/2002 20:50:40
> No one has refuted my idea of clearing the cache when a more specific
> route (longer mask length) than the cached route is added to the
> table. This does a better job of maintaining the cache when possible
> and adds a small amount of code.
It's better, because it eliminates the problem in one particular case.
However, it does not catch all cases; in particular, it does not catch
the case where the original of the cached route is deleted. (This
*might* not be an issue, if I missed something in the invalidation code
and it does manage to invalidate the cached route.)
However, I am not at all sure there are no other cases, and clearing
the cache whenever the routing table is touched catches them all. I
don't think the additional cache flushes are that high a price to pay
for the certainty that the problem won't recur.
Or, for that matter, the fix I sent in with the PR does almost as good
a job, recovering within at most one second from a bogus cached route
no matter how it happened.
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