On Wed, Jun 19, 2024 at 1:30 PM Ilya Maximets <[email protected]> wrote: > > On 6/19/24 16:07, Xin Long wrote: > > On Wed, Jun 19, 2024 at 8:58 AM Ilya Maximets <[email protected]> wrote: > >> > >> On 6/18/24 17:50, Ilya Maximets wrote: > >>> On 6/18/24 16:58, Xin Long wrote: > >>>> On Tue, Jun 18, 2024 at 7:34 AM Ilya Maximets <[email protected]> wrote: > >>>>> > >>>>> On 6/17/24 22:10, Ilya Maximets wrote: > >>>>>> On 7/16/23 23:09, Xin Long wrote: > >>>>>>> By not setting IPS_CONFIRMED in tmpl that allows the exp not to be > >>>>>>> removed > >>>>>>> from the hashtable when lookup, we can simplify the exp processing > >>>>>>> code a > >>>>>>> lot in openvswitch conntrack. > >>>>>>> > >>>>>>> Signed-off-by: Xin Long <[email protected]> > >>>>>>> --- > >>>>>>> net/openvswitch/conntrack.c | 78 > >>>>>>> +++++-------------------------------- > >>>>>>> 1 file changed, 10 insertions(+), 68 deletions(-) > >>>>>>> > >>>>>>> diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c > >>>>>>> index 331730fd3580..fa955e892210 100644 > >>>>>>> --- a/net/openvswitch/conntrack.c > >>>>>>> +++ b/net/openvswitch/conntrack.c > >>>>>>> @@ -455,45 +455,6 @@ static int ovs_ct_handle_fragments(struct net > >>>>>>> *net, struct sw_flow_key *key, > >>>>>>> return 0; > >>>>>>> } > >>>>>>> > >>>>>>> -static struct nf_conntrack_expect * > >>>>>>> -ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone > >>>>>>> *zone, > >>>>>>> - u16 proto, const struct sk_buff *skb) > >>>>>>> -{ > >>>>>>> - struct nf_conntrack_tuple tuple; > >>>>>>> - struct nf_conntrack_expect *exp; > >>>>>>> - > >>>>>>> - if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, net, > >>>>>>> &tuple)) > >>>>>>> - return NULL; > >>>>>>> - > >>>>>>> - exp = __nf_ct_expect_find(net, zone, &tuple); > >>>>>>> - if (exp) { > >>>>>>> - struct nf_conntrack_tuple_hash *h; > >>>>>>> - > >>>>>>> - /* Delete existing conntrack entry, if it clashes with > >>>>>>> the > >>>>>>> - * expectation. This can happen since conntrack ALGs do > >>>>>>> not > >>>>>>> - * check for clashes between (new) expectations and > >>>>>>> existing > >>>>>>> - * conntrack entries. nf_conntrack_in() will check the > >>>>>>> - * expectations only if a conntrack entry can not be > >>>>>>> found, > >>>>>>> - * which can lead to OVS finding the expectation (here) > >>>>>>> in the > >>>>>>> - * init direction, but which will not be removed by the > >>>>>>> - * nf_conntrack_in() call, if a matching conntrack entry > >>>>>>> is > >>>>>>> - * found instead. In this case all init direction > >>>>>>> packets > >>>>>>> - * would be reported as new related packets, while reply > >>>>>>> - * direction packets would be reported as un-related > >>>>>>> - * established packets. > >>>>>>> - */ > >>>>>>> - h = nf_conntrack_find_get(net, zone, &tuple); > >>>>>>> - if (h) { > >>>>>>> - struct nf_conn *ct = > >>>>>>> nf_ct_tuplehash_to_ctrack(h); > >>>>>>> - > >>>>>>> - nf_ct_delete(ct, 0, 0); > >>>>>>> - nf_ct_put(ct); > >>>>>>> - } > >>>>>>> - } > >>>>>>> - > >>>>>>> - return exp; > >>>>>>> -} > >>>>>>> - > >>>>>>> /* This replicates logic from nf_conntrack_core.c that is not > >>>>>>> exported. */ > >>>>>>> static enum ip_conntrack_info > >>>>>>> ovs_ct_get_info(const struct nf_conntrack_tuple_hash *h) > >>>>>>> @@ -852,36 +813,16 @@ static int ovs_ct_lookup(struct net *net, > >>>>>>> struct sw_flow_key *key, > >>>>>>> const struct ovs_conntrack_info *info, > >>>>>>> struct sk_buff *skb) > >>>>>>> { > >>>>>>> - struct nf_conntrack_expect *exp; > >>>>>>> - > >>>>>>> - /* If we pass an expected packet through nf_conntrack_in() the > >>>>>>> - * expectation is typically removed, but the packet could still > >>>>>>> be > >>>>>>> - * lost in upcall processing. To prevent this from happening we > >>>>>>> - * perform an explicit expectation lookup. Expected connections > >>>>>>> are > >>>>>>> - * always new, and will be passed through conntrack only when > >>>>>>> they are > >>>>>>> - * committed, as it is OK to remove the expectation at that time. > >>>>>>> - */ > >>>>>>> - exp = ovs_ct_expect_find(net, &info->zone, info->family, skb); > >>>>>>> - if (exp) { > >>>>>>> - u8 state; > >>>>>>> - > >>>>>>> - /* NOTE: New connections are NATted and Helped only when > >>>>>>> - * committed, so we are not calling into NAT here. > >>>>>>> - */ > >>>>>>> - state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | > >>>>>>> OVS_CS_F_RELATED; > >>>>>>> - __ovs_ct_update_key(key, state, &info->zone, > >>>>>>> exp->master); > >>>>>> > >>>>>> Hi, Xin, others. > >>>>>> > >>>>>> Unfortunately, it seems like removal of this code broke the expected > >>>>>> behavior. > >>>>>> OVS in userspace expects that SYN packet of a new related FTP > >>>>>> connection will > >>>>>> get +new+rel+trk flags, but after this patch we're only getting > >>>>>> +rel+trk and not > >>>>>> new. This is a problem because we need to commit this connection with > >>>>>> the label > >>>>>> and we do that for +new packets. If we can't get +new packet we'll > >>>>>> have to commit > >>>>>> every single +rel+trk packet, which doesn't make a lot of sense. And > >>>>>> it's a > >>>>>> significant behavior change regardless. > >>>>> > >>>>> Interestingly enough I see +new+rel+trk packets in cases without SNAT, > >>>>> but we can only get +rel+trk in cases with SNAT. So, this may be just > >>>>> a generic conntrack bug somewhere. At least the behavior seems fairly > >>>>> inconsistent. > >>>>> > >>>> In nf_conntrack, IP_CT_RELATED and IP_CT_NEW do not exist at the same > >>>> time. With this patch, we expect OVS_CS_F_RELATED and OVS_CS_F_NEW > >>>> are set at the same time by ovs_ct_update_key() when this related ct > >>>> is not confirmed. > >>>> > >>>> The check-kernel test of "FTP SNAT orig tuple" skiped on my env somehow: > >>>> > >>>> # make check-kernel > >>>> 144: conntrack - FTP SNAT orig tuple skipped (system-traffic.at:7295) > >>>> > >>>> Any idea why? or do you know any other testcase that expects +new+rel+trk > >>>> but returns +rel+trk only? > >>> > >>> You need to install lftp and pyftpdlib. The pyftpdlib may only be > >>> available > >>> via pip on some systems. > >>> > >>>> > >>>> Thanks. > >>>>>> > >>>>>> Could you, please, take a look? > >>>>>> > >>>>>> The issue can be reproduced by running check-kernel tests in OVS repo. > >>>>>> 'FTP SNAT orig tuple' tests fail 100% of the time. > >>>>>> > >>>>>> Best regards, Ilya Maximets. > >>>>> > >>> > >> > >> Hmm. After further investigation, it seems that the issue is not about ct > >> state, > >> but the ct label. Before this commit we had information about both the > >> original > >> tuple of the parent connection and the mark/label of the parent connection: > >> > > Make senses. Now I can see the difference after this commit. > > We will need a fix in __ovs_ct_update_key() to copy mark & label from > > ct->master for exp ct. > > > > @@ -196,8 +196,8 @@ static void __ovs_ct_update_key(struct sw_flow_key > > *key, u8 state, > > { > > key->ct_state = state; > > key->ct_zone = zone->id; > > - key->ct.mark = ovs_ct_get_mark(ct); > > - ovs_ct_get_labels(ct, &key->ct.labels); > > + key->ct.mark = 0; > > + memset(&key->ct.labels, 0, OVS_CT_LABELS_LEN); > > > > if (ct) { > > const struct nf_conntrack_tuple *orig; > > @@ -205,6 +205,8 @@ static void __ovs_ct_update_key(struct sw_flow_key > > *key, u8 state, > > /* Use the master if we have one. */ > > if (ct->master) > > ct = ct->master; > > + key->ct.mark = ovs_ct_get_mark(ct); > > + ovs_ct_get_labels(ct, &key->ct.labels); > > orig = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; > > > > /* IP version must match with the master connection. */ > > > > We may need to run some regression tests for such a change. > > Thank, Xin! This seems like a change in the right direction and it fixes > this particular test. But, I guess, we should get mark/labels from the > master connection only if it is not yet confirmed. Users may commit different > labels for the related connection. This should be more in line with the > previous behavior. > > What do you think? > You're right. Also, I noticed the related ct->mark is set to master ct->mark in init_conntrack() as well as secmark when creating the related ct.
Hi, Florian, Any reason why the labels are not set to master ct's in there? Thanks. > > > > > Thanks. > > > >> system@ovs-system: miss upcall: > >> recirc_id(0x2),dp_hash(0),skb_priority(0),in_port(3),skb_mark(0),ct_state(0x25), > >> ct_zone(0x1),ct_mark(0),ct_label(0x4d2000000000000000000000001), > >> ct_tuple4(src=10.1.1.1,dst=10.1.1.2,proto=6,tp_src=50648,tp_dst=21), > >> eth(src=de:d9:f3:c8:5a:3a,dst=80:88:88:88:88:88),eth_type(0x0800), > >> ipv4(src=10.1.1.2,dst=10.1.1.9,proto=6,tos=0,ttl=64,frag=no), > >> tcp(src=57027,dst=38153),tcp_flags(syn) > >> > >> But after this change, we still have the original tuple of the parent > >> connection, > >> but the label is no longer in the flow key: > >> > >> system@ovs-system: miss upcall: > >> recirc_id(0x2),dp_hash(0),skb_priority(0),in_port(3),skb_mark(0),ct_state(0x25), > >> ct_zone(0x1),ct_mark(0),ct_label(0), > >> ct_tuple4(src=10.1.1.1,dst=10.1.1.2,proto=6,tp_src=34668,tp_dst=21), > >> eth(src=66:eb:74:c6:79:24,dst=80:88:88:88:88:88),eth_type(0x0800), > >> ipv4(src=10.1.1.2,dst=10.1.1.9,proto=6,tos=0,ttl=64,frag=no), > >> tcp(src=49529,dst=35459),tcp_flags(syn) > >> > >> ct_state(0x25) == +new+rel+trk > >> > >> Best regards, Ilya Maximets. > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
