Hi Florian, Florian Westphal <[email protected]> writes:
> At this time, conntrack either returns NF_ACCEPT or NF_DROP. > To improve debuging it would be nice to be able to replace NF_DROP > verdict with NF_DROP_REASON() helper, > > This helper releases the skb instantly (so drop_monitor can pinpoint > precise location) and returns NF_STOLEN. > > Prepare call sites to deal with this before introducing such changes > in conntrack and nat core. > > Signed-off-by: Florian Westphal <[email protected]> > --- AFAIU, these changes are only impacting the existing NF_DROP cases, and won't impact how ovs + netfilter communicate about invalid packets. One important thing to note is that we rely on: * Note that if the packet is deemed invalid by conntrack, skb->_nfct will be * set to NULL and 0 will be returned. Based on this, my understanding is if packet isn't part of a valid connection, skb->_nfct is NULL and NF_ACCEPT is returned. If this changes, those flow pipelines matching on ct_state(+inv+trk) will no longer function as expected since we will bail early. I think this comment will also apply to the act_ct change as well. > net/openvswitch/conntrack.c | 47 +++++++++++++++++++++++++++++-------- > 1 file changed, 37 insertions(+), 10 deletions(-) > > diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c > index 3b980bf2770b..8eb1d644b741 100644 > --- a/net/openvswitch/conntrack.c > +++ b/net/openvswitch/conntrack.c > @@ -679,6 +679,8 @@ static int ovs_ct_nat(struct net *net, struct sw_flow_key > *key, > action |= BIT(NF_NAT_MANIP_DST); > > err = nf_ct_nat(skb, ct, ctinfo, &action, &info->range, info->commit); > + if (err != NF_ACCEPT) > + return err; > > if (action & BIT(NF_NAT_MANIP_SRC)) > ovs_nat_update_key(key, skb, NF_NAT_MANIP_SRC); > @@ -697,6 +699,22 @@ static int ovs_ct_nat(struct net *net, struct > sw_flow_key *key, > } > #endif > > +static int verdict_to_errno(unsigned int verdict) > +{ > + switch (verdict & NF_VERDICT_MASK) { > + case NF_ACCEPT: > + return 0; > + case NF_DROP: > + return -EINVAL; > + case NF_STOLEN: > + return -EINPROGRESS; > + default: > + break; > + } > + > + return -EINVAL; > +} > + > /* Pass 'skb' through conntrack in 'net', using zone configured in 'info', if > * not done already. Update key with new CT state after passing the packet > * through conntrack. > @@ -735,7 +753,7 @@ static int __ovs_ct_lookup(struct net *net, struct > sw_flow_key *key, > > err = nf_conntrack_in(skb, &state); > if (err != NF_ACCEPT) > - return -ENOENT; > + return verdict_to_errno(err); > > /* Clear CT state NAT flags to mark that we have not yet done > * NAT after the nf_conntrack_in() call. We can actually clear > @@ -762,9 +780,12 @@ static int __ovs_ct_lookup(struct net *net, struct > sw_flow_key *key, > * the key->ct_state. > */ > if (info->nat && !(key->ct_state & OVS_CS_F_NAT_MASK) && > - (nf_ct_is_confirmed(ct) || info->commit) && > - ovs_ct_nat(net, key, info, skb, ct, ctinfo) != NF_ACCEPT) { > - return -EINVAL; > + (nf_ct_is_confirmed(ct) || info->commit)) { > + int err = ovs_ct_nat(net, key, info, skb, ct, ctinfo); > + > + err = verdict_to_errno(err); > + if (err) > + return err; > } > > /* Userspace may decide to perform a ct lookup without a helper > @@ -795,9 +816,12 @@ static int __ovs_ct_lookup(struct net *net, struct > sw_flow_key *key, > * - When committing an unconfirmed connection. > */ > if ((nf_ct_is_confirmed(ct) ? !cached || add_helper : > - info->commit) && > - nf_ct_helper(skb, ct, ctinfo, info->family) != NF_ACCEPT) { > - return -EINVAL; > + info->commit)) { > + int err = nf_ct_helper(skb, ct, ctinfo, info->family); > + > + err = verdict_to_errno(err); > + if (err) > + return err; > } > > if (nf_ct_protonum(ct) == IPPROTO_TCP && > @@ -1001,10 +1025,9 @@ static int ovs_ct_commit(struct net *net, struct > sw_flow_key *key, > /* This will take care of sending queued events even if the connection > * is already confirmed. > */ > - if (nf_conntrack_confirm(skb) != NF_ACCEPT) > - return -EINVAL; > + err = nf_conntrack_confirm(skb); > > - return 0; > + return verdict_to_errno(err); > } > > /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero > @@ -1039,6 +1062,10 @@ int ovs_ct_execute(struct net *net, struct sk_buff > *skb, > else > err = ovs_ct_lookup(net, key, info, skb); > > + /* conntrack core returned NF_STOLEN */ > + if (err == -EINPROGRESS) > + return err; > + > skb_push_rcsum(skb, nh_ofs); > if (err) > ovs_kfree_skb_reason(skb, OVS_DROP_CONNTRACK); _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
