Re: [NETFILTER] early_drop() imrovement (v4)

From: Vasily Averin
Date: Wed Jun 27 2007 - 09:02:36 EST


Patrick McHardy wrote:
> Vasily Averin wrote:
>> it is incorrect,
>> We should count the number of checked _conntracks_, but you count the number of
>> hash buckets. I.e "i" should be incremented/checked inside the nested loop.
>
>
> I misunderstood your patch then. This one should be better.
> +static int early_drop(unsigned int hash)
> {
> /* Use oldest entry, which is roughly LRU */
> struct nf_conntrack_tuple_hash *h;
> struct nf_conn *ct = NULL, *tmp;
> struct hlist_node *n;
> - int dropped = 0;
> + unsigned int i;
> + int dropped = 0, cnt = NF_CT_EVICTION_RANGE;
>
> read_lock_bh(&nf_conntrack_lock);
> - hlist_for_each_entry(h, n, chain, hnode) {
> - tmp = nf_ct_tuplehash_to_ctrack(h);
> - if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
> - ct = tmp;
> + for (i = 0; i < nf_conntrack_htable_size; i++) {
> + hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode) {
> + tmp = nf_ct_tuplehash_to_ctrack(h);
> + if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
> + ct = tmp;
> + if (--cnt <= 0)
> + break;
> + }
> + hash = (hash + 1) % nf_conntrack_htable_size;
> }

it is incorrect again: when cnt=0 you should break both cycles.

thank you,
Vasily Averin
-
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