Thanks. We will avoid sending the ND packets to conntrack. In the long run, its good to fix this inconsistency as Jarno suggested.
On Sat, Dec 17, 2016 at 2:55 AM, Jarno Rajahalme <[email protected]> wrote: > > > On Dec 16, 2016, at 9:12 AM, Sridhar Gaddam <[email protected]> wrote: > > > > > > > > > > On Tue, Dec 13, 2016 at 1:12 PM, Daniele Di Proietto < > [email protected]> > > wrote: > > > >> 2016-12-12 3:21 GMT-08:00 Sridhar Gaddam <[email protected]>: > >>> 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://github.com/openvswitch/ovs/blob/master/NEWS > >> > >> 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”. 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://lists.opendaylight.org/pipermail/netvirt-dev/ > > 2016-December/002527.html > > > > Thanks, > > --Sridhar. > > > > > >> > >>> > >>> Thank you, > >>> --Sridhar. > >>> _______________________________________________ > >>> dev mailing list > >>> [email protected] > >>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev > >> > > _______________________________________________ > > dev mailing list > > [email protected] > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
