Messages in this thread | | | Date | Fri, 06 Apr 2007 17:08:28 +0200 | From | Patrick McHardy <> | Subject | Re: [PATCH 2.6.21-rc6] [netfilter] early_drop imrovement |
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Vasily Averin wrote: > No, I've not investigated this scenario. It looks like you are right and my > patch can leads to a long delays. > > In my experiments I've decreased ip_conntrack_max lower than number of hash > buckets and got the "table full, dropping packet" errors in logs. I've looked on > the conntrack list and found a huge number of conntracks that can be freed. > However my hash bucket was empty and therefore I even did not have any chances > to free something. That's why I would like to check the other hash buckets too. > > Ok, let's limit the number of conntracks that can be checked inside > early_drop(). What do you prefer: some round number (for example 100) or > fraction of ip_conntrack_max (for example 1%)?
A (small) fraction sounds better. We could even consider keeping track of the number of conntracks that can be evicted (not assured), so in a DOS situation we could save unnecessary table scans. Not sure if its worth the effort though.
Anyway, please base your patch on the net-2.6.22 tree, which doesn't include ip_conntrack anymore.
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