Jakub Kicinski <[email protected]> wrote: > On Sun, 16 Jul 2023 17:09:16 -0400 Xin Long wrote: > > With the OVS upcall, the original ct in the skb will be dropped, and when > > the skb comes back from userspace it has to create a new ct again through > > nf_conntrack_in() in either OVS __ovs_ct_lookup() or TC tcf_ct_act(). > > > > However, the new ct will not be able to have the exp as the original ct > > has taken it away from the hash table in nf_ct_find_expectation(). This > > will cause some flow never to be matched, like: > > > > 'ip,ct_state=-trk,in_port=1 actions=ct(zone=1)' > > 'ip,ct_state=+trk+new+rel,in_port=1 actions=ct(commit,zone=1)' > > 'ip,ct_state=+trk+new+rel,in_port=1 actions=ct(commit,zone=2),normal' > > > > if the 2nd flow triggers the OVS upcall, the 3rd flow will never get > > matched. > > > > OVS conntrack works around this by adding its own exp lookup function to > > not remove the exp from the hash table and saving the exp and its master > > info to the flow keys instead of create a real ct. But this way doesn't > > work for TC act_ct. > > > > The patch 1/3 allows nf_ct_find_expectation() not to remove the exp from > > the hash table if tmpl is set with IPS_CONFIRMED when doing lookup. This > > allows both OVS conntrack and TC act_ct to have a simple and clear fix > > for this problem in the patch 2/3 and 3/3. > > Florian, Pablo, any opinion on these?
Sorry for the silence. I dislike moving tc/ovs artifacts into the conntrack core. But so far I could not come up with a counter-proposal, and it doesn't look too outrageous. Let me look at it again later today (its early morning here) and I will get back to this in my late evening. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
