Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote: > On Tue, Feb 04, 2014 at 12:29:25AM +0100, Florian Westphal wrote: > > Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote: > > > diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c > > > index 4d1fb5d..356bef5 100644 > > > --- a/net/netfilter/nf_conntrack_core.c > > > +++ b/net/netfilter/nf_conntrack_core.c > > > @@ -448,7 +448,9 @@ nf_conntrack_hash_check_insert(struct nf_conn *ct) > > > goto out; > > > > > > add_timer(&ct->timeout); > > > - nf_conntrack_get(&ct->ct_general); > > > + smp_wmb(); > > > + /* The caller holds a reference to this object */ > > > + atomic_set(&ct->ct_general.use, 2); > > > > What happens when the skb is dropped before confirmation? > > If you refer to the spot above, conntracks added via ctnetlink are > always confirmed and the refcount will become 1 after insertion into > the hashes. In the packet path, the refcount is 1 for unconfirmed > conntracks, Right, sorry. I missed this. You only want to delay the init-to-1 until the conntrack is inserted into the unconfirmed list. However, I think there is still a problem with the atomic_set to 2 above. What about e.g. Prerouting -> set refcnt to 1 (clone) (clone) (refcnt is 3) forward/postrouting -> confirmation (refcnt reset to two) I think this could happen at least with netfilter on-top-of bridge when dealing with e.g. udp mcast. (i am looking at br_forward and deliver_clone in particular). I think you could just leave hash_check_insert() alone? -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
