2016-12-19 21:25 GMT-08:00 Darrell Ball <db...@vmware.com>: > > > From: Jarno Rajahalme <ja...@ovn.org> > Date: Monday, December 19, 2016 at 2:30 PM > To: Darrell Ball <db...@vmware.com> > Cc: Sridhar Gaddam <sgad...@redhat.com>, "ovs-dev@openvswitch.org" > <ovs-dev@openvswitch.org>, Srikanth Vavilapalli > <srikanth.vavilapa...@ericsson.com> > Subject: Re: [ovs-dev] OVS2.6+dpdk IPv6 Conntrack support > > > On Dec 19, 2016, at 1:29 PM, Darrell Ball > <db...@vmware.com<mailto:db...@vmware.com>> wrote: > > > > On 12/16/16, 1:25 PM, > "ovs-dev-boun...@openvswitch.org<mailto:ovs-dev-boun...@openvswitch.org> on > behalf of Jarno Rajahalme" > <ovs-dev-boun...@openvswitch.org<mailto:ovs-dev-boun...@openvswitch.org> on > behalf of ja...@ovn.org<mailto:ja...@ovn.org>> wrote: > > > > On Dec 16, 2016, at 9:12 AM, Sridhar Gaddam > <sgad...@redhat.com<mailto:sgad...@redhat.com>> wrote: > > > > > On Tue, Dec 13, 2016 at 1:12 PM, Daniele Di Proietto > <diproiet...@ovn.org<mailto:diproiet...@ovn.org>> > wrote: > > > 2016-12-12 3:21 GMT-08:00 Sridhar Gaddam > <sgad...@redhat.com<mailto:sgad...@redhat.com>>: > > Hello, > > In our setup, we are using OVS 2.6+dpdk and are noticing that conntrack > for > > IPv6 traffic is NOT working. > However, the same use-case works fine for Ipv4 traffic. > > We had a look at OVS 2.6 release notes[1], and it mentions that "Basic > connection tracking for the user space datapath (no ALG, fragmentation or > NAT support yet) is supported". > There is no explicit mention of IPv6. So, can someone please confirm if > conntrack for IPv6 is supported in OVS2.6+dpdk? > > [1] > https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_openvswitch_ovs_blob_master_NEWS&d=DgIGaQ&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=mKE_yUtefdGBHPQFzof9bTj8s0GLdzeq7JAQxtXKOiw&s=tLk5RAXCyQ-F125wXNI-MI4d4MY3PYCwrgBY6QyI-90&e= > > IPv6 should be supported. There are a few testcases in the system > userspace testsuite (`make check-system-userspace`) that cover that. > > Could you tell us more about your setup? > > > Sorry for the delay in response. I do not have a local setup to reproduce > the issue, so was trying to gather some details from the team that > originally noticed this. > > Basically we are seeing this issue in OpenDaylight use-case when using > OVS2.6+dpdk along with conntrack. > > A simplified view of the use-case is as follows. > 1. We have a VM spawned with MAC of "fa:16:3e:6e:9f:b0" and it is sending > out a Neighbor Solicitation for another VM on the same network. > 2. We use conntrack for tracking the connections, so the Neighbor > Solicitation packets initially hit flow (a) in table40, and in table41 the > ct_state matches to "+inv" and are getting dropped (flow e). > 3. This behavior (i.e., ct_state=+inv+trk) is seen for ICMPv6 Neighbor > Solicitation messages and not for other IPv6 TCP/UDP traffic. > 4. Also, this behavior is NOT seen when using OVS kernel datapath (i.e., in > table 41, we see that ct_state matches to +new+trk instead of +inv+trk) > > This seems to be an inconsistency in handling packets that are not > tracked. Even Linux kernel conntrack does > not track neighbor discovery for obvious reasons, but it still attaches a > special “notrack” entry with the packet > and reports it as “NEW”. > > How does the kernel know these are valid/safe ND packets ? > > I’m guessing it doesn’t. > > Jarno > > Packets are sent thru. conntrack to filter bad flows, but in this case, > conntrack is not doing that and records to that effect (i.e. notrack). > But we already know conntrack does not handle ND, so why send these > packets thru. conntrack in the first place, which was your suggestion earlier. > > Also, is there some expectation that conntrack should allow all non-tracked > packets > thru., by default ? > iptables allows the user to open these holes via explicit configuration. >
There is a specific test case in the userspace testsuite that made sure that we treated neighbor discovery as invalid: ofproto-dpif - conntrack - untrackable traffic I thought it made sense because I didn't see much value in handling stateless policies in the connection tracker. I guess we can change the behavior to be consistent with the kernel. I sent two patches here: https://mail.openvswitch.org/pipermail/ovs-dev/2016-December/326508.html https://mail.openvswitch.org/pipermail/ovs-dev/2016-December/326509.html The first one is a fix for an unrelated bug that I noticed while developing the second one. Thanks for reporting this, Daniele > > > Flagging ND traffic as “+inv” is probably not the right thing to do, but > the workaround for now is to not send ND > packets to conntrack in the first place. > > Jarno > > > Srikanth, who is noticing this issue, was also informed by his switch team > that OVS > conntrack > explicitly treats the IPv6 Neighbor Solicitation as an invalid connection. > For more details, please see the email thread [*] where this issue is > discussed. > > We are trying to see if we should bypass conntrack for NDP packets. In the > meantime, if you know the specific reason why NS packets are treated this > way, can you please let us know? > > Sample flows: > a) table=40, n_packets=246, n_bytes=21156, priority=61010,ipv6,dl_src=fa: > 16:3e:6e:9f:b0,ipv6_src=2001:db8:1234:0:f816:3eff:fe6e:9fb0 > actions=ct(table=41,zone=5002) > b) table=41, n_packets=0, n_bytes=0, > priority=62020,ct_state=-new+est-rel-inv+trk > actions=resubmit(,17) > c) table=41, n_packets=0, n_bytes=0, > priority=62020,ct_state=-new-est+rel-inv+trk > actions=resubmit(,17) > d) table=41, n_packets=0, n_bytes=0, priority=12806,ct_state=+new+ > trk,ipv6,metadata=0x19a80000000000/0x1fffff0000000000 > actions=ct(commit,zone=5002),resubmit(,17) > e) table=41, n_packets=246, n_bytes=21156, priority=62020,ct_state=+inv+trk > actions=drop > > [*] > https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.opendaylight.org_pipermail_netvirt-2Ddev_&d=DgIGaQ&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=mKE_yUtefdGBHPQFzof9bTj8s0GLdzeq7JAQxtXKOiw&s=6nqF_U69noH6tzvthi34Sz4vwvywPT7jA9PJkJaLawE&e= > 2016-December/002527.html > > Thanks, > --Sridhar. > > > > > > > Thank you, > --Sridhar. > _______________________________________________ > dev mailing list > d...@openvswitch.org<mailto:d...@openvswitch.org> > https://urldefense.proofpoint.com/v2/url?u=https-3A__mail.openvswitch.org_mailman_listinfo_ovs-2Ddev&d=DgIGaQ&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=mKE_yUtefdGBHPQFzof9bTj8s0GLdzeq7JAQxtXKOiw&s=5DbN-MLADnaU83fHKDTMJSqeFvaerpR69ytO3BLbE9k&e= > > _______________________________________________ > dev mailing list > d...@openvswitch.org<mailto:d...@openvswitch.org> > https://urldefense.proofpoint.com/v2/url?u=https-3A__mail.openvswitch.org_mailman_listinfo_ovs-2Ddev&d=DgIGaQ&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=mKE_yUtefdGBHPQFzof9bTj8s0GLdzeq7JAQxtXKOiw&s=5DbN-MLADnaU83fHKDTMJSqeFvaerpR69ytO3BLbE9k&e= > > _______________________________________________ > dev mailing list > d...@openvswitch.org<mailto:d...@openvswitch.org> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__mail.openvswitch.org_mailman_listinfo_ovs-2Ddev&d=DgIGaQ&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=mKE_yUtefdGBHPQFzof9bTj8s0GLdzeq7JAQxtXKOiw&s=5DbN-MLADnaU83fHKDTMJSqeFvaerpR69ytO3BLbE9k&e= > > > _______________________________________________ > dev mailing list > d...@openvswitch.org > https://mail.openvswitch.org/mailman/listinfo/ovs-dev _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
