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    SubjectRe: [PATCH v3] netfilter: save the hash of the tuple in the original direction for latter use
    Le vendredi 20 août 2010 à 22:53 +0800, Changli Gao a écrit :
    > Since we don't change the tuple in the original direction, we can save it
    > in ct->tuplehash[IP_CT_DIR_REPLY].hnode.pprev for __nf_conntrack_confirm()
    > use.
    > __hash_conntrack() is split into two steps: ____hash_conntrack() is used
    > to get the raw hash, and __hash_bucket() is used to get the bucket id.
    > In SYN-flood case, early_drop() doesn't need to recompute the hash again.
    > Signed-off-by: Changli Gao <>
    > ---

    Hmm... so to accept a few more SYN packets per second in SYNFLOOD
    attack, we slow a bit normal operations ? (adding one test on each
    packet going through conntrack)

    If yes (I dont think we should, hackers are stronger than you anyway,
    just face it)

    __read_mostly on nf_conntrack_rnd

    What would happen if we let the initialization of nf_conntrack_rnd
    only in the insertion case (like currently done) ?
    Only the first packet received on the machine/conntrack might be hashed
    on a wrong slot. Is it a big deal ? If yes, maybe find a way to
    recompute the hash in this case, instead of reusing 'wrong' one ?

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      Last update: 2010-08-20 17:13    [W:0.024 / U:2.012 seconds]
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