On Wed, Jun 28, 2017 at 7:06 AM, Numan Siddique <[email protected]> wrote:
> > > On Jun 23, 2017 2:25 PM, "Joe Stringer" <[email protected]> wrote: > > On 22 June 2017 at 16:08, Numan Siddique <[email protected]> wrote: > > > > > > On Jun 23, 2017 1:31 AM, "Joe Stringer" <[email protected]> wrote: > > > > On 22 June 2017 at 04:16, Numan Siddique <[email protected]> wrote: > >> > >> > >> On Thu, Jun 22, 2017 at 5:45 AM, Joe Stringer <[email protected]> wrote: > >>> > >>> On 21 June 2017 at 04:19, Numan Siddique <[email protected]> wrote: > >>> > > >>> > > >>> > On Tue, Jun 20, 2017 at 3:11 AM, Joe Stringer <[email protected]> wrote: > >>> >> > >>> >> On 19 June 2017 at 00:37, Numan Siddique <[email protected]> > wrote: > >>> >> > > >>> >> > > >>> >> > On Fri, Jun 16, 2017 at 11:22 PM, Joe Stringer <[email protected]> > wrote: > >>> >> >> > >>> >> >> On 15 June 2017 at 22:20, Numan Siddique <[email protected]> > >>> >> >> wrote: > >>> >> >> > > >>> >> >> > > >>> >> >> > On Thu, Jun 15, 2017 at 5:06 PM, Aswin S < > [email protected]> > >>> >> >> > wrote: > >>> >> >> >> > >>> >> >> >> > >>> >> >> >> Adding some more info here, Thanks Numan! for pointing to > this. > >>> >> >> >> > >>> >> >> >> The issue I am facing looks similar to the one described in > [1] > >>> >> >> >> and > >>> >> >> >> [2]. > >>> >> >> >> But it seems the issue is not yet fixed. Is there a plan to > fix > >>> >> >> >> this > >>> >> >> >> soon? > >>> >> >> >> In Opendaylight security groups is implemented using > >>> >> >> >> ovs-conntrack. > >>> >> >> >> So > >>> >> >> >> the > >>> >> >> >> flow based router ping responder and floating IP > translations > >>> >> >> >> hits > >>> >> >> >> this > >>> >> >> >> issue. > >>> >> >> >> > >>> >> >> >> > >>> >> >> >> > >>> >> >> >> > >>> >> >> >> > >>> >> >> >> [1]https://mail.openvswitch.org/pipermail/ovs-dev/2017-March > /329542.html > >>> >> >> >> [2]https://patchwork.ozlabs.org/patch/739796/ > >>> >> >> >> > >>> >> >> > > >>> >> >> > The same issuse is also seen in OVN as pointed by Aswin. > >>> >> >> > > >>> >> >> > Joe - If you remember, we had a chat about this same issue > during > >>> >> >> > the > >>> >> >> > Openstack Boston summit. > >>> >> >> > >>> >> >> Hi Numan, yeah I recall we had this discussion. I didn't have > much > >>> >> >> clarity on where we're at with this. Looking at patchwork, I > >>> >> >> provided > >>> >> >> some feedback on the RFC. The most straightforward approach seems > >>> >> >> to > >>> >> >> be adding a nf_ct_set(skb, NULL, 0); call for each of the 5tuple > >>> >> >> "set" > >>> >> >> actions in the datapath. > >>> >> > > >>> >> > > >>> >> > Thanks. I will try it out and let you know how it went. > >>> >> > I remember, I was suppose to provide more clarity after our > >>> >> > discussion. > >>> >> > My > >>> >> > apologies. It slipped out of my head. > >>> >> > >>> >> No worries, let me know how you go. > >>> > > >>> > > >>> > I tried this and it didn't work. In fact the function set_ipv4 (in > >>> > datapath/actions.c) is not even called. > >>> > > >>> > Below is the flow which responds to ICMP request packet > >>> > > >>> > cookie=0x64913aa, duration=566.801s, table=17, n_packets=3, > >>> > n_bytes=294, > >>> > idle_age=144, > >>> > > >>> > priority=90,icmp,metadata=0x3,nw_dst=192.168.0.1,icmp_type=8 > ,icmp_code=0 > >>> > > >>> > > >>> > actions=push:NXM_OF_IP_SRC[],push:NXM_OF_IP_DST[],pop:NXM_OF > _IP_SRC[],pop:NXM_OF_IP_DST[],load:0xff->NXM_NX_IP_TTL[],loa > d:0->NXM_OF_ICMP_TYPE[],load:0x1->NXM_NX_REG10[0],resubmit(,18) > >>> > > >>> > Thanks > >>> > Numan > >>> > >>> Hi Numan, > >>> > >>> How are you going about making these changes and testing them? Could > >>> you double-check that the correct module was loaded when you ran the > >>> test? Given that the IP src and dst are being modified from the flow > >>> you described above, I think that the set_ipv4 function should be > >>> called for such flows. > >>> > >>> Some sanity checks: > >>> # modinfo openvswitch > >>> # find /lib/modules -name openvswitch.ko* | xargs ls -l > >>> > >>> Might want to double-check that your depmod.d settings are set > >>> correctly so it loads the new module instead of the one that comes > >>> with your kernel. > >>> # man depmod.d > >>> > >>> Of course, the above doesn't necessarily apply if you're making > >>> changes directly in your kernel tree and loading the module from there > >>> (for example, using insmod, or make modules_install into the original > >>> module path). > >>> > >> > >> Hi Joe, > >> > >> I verified that the loaded openvswitch module loaded is indeed modified > by > >> me. I also put some printks in functions like "ovs_packet_cmd_execute" > to > >> verify. > >> > >> I created my testing scenario as per the commands here [1]. There are 2 > >> logical ports with IPs 192.168.0.2 and 192.168.0.3 associated to 2 > >> namespaces ns1 and ns2. The logical switch is also connected to a > logical > >> router. > >> > >> I pinged from 192.168.0.2 to 192.168.0.3 continuously and monitored the > >> kernel flows with the command - > >> > >> $watch -n1 -d "sudo ovs-dpctl dump-flows system@ovs-system" > >> > >> recirc_id(0),in_port(3),eth(src=00:00:00:00:00:00/01:00:00:0 > 0:00:00,dst=50:54:00:00:00:01),eth_type(0x0800),ipv4(dst=192 > .168.0.2/255.255.255.254,frag=no), > >> packets:28, bytes:2744, used:0.323s, actions:2 > >> > >> recirc_id(0),in_port(2),eth(src=00:00:00:00:00:00/01:00:00:0 > 0:00:00,dst=50:54:00:00:00:02),eth_type(0x0800),ipv4(dst=192 > .168.0.2/255.255.255.254,frag=no), > >> packets:28, bytes:2744, used:0.323s, actions:3 > >> > >> > >> I pinged from 192.168.0.2 to 192.168.0.1 (without any ACLs, so the ping > >> would be successful), I observed that the action is always userspace > and I > >> could see that the function "odp_execute_masked_set_action" in > >> lib/odp-execute.c is called in vswitchd. > >> > >> $watch -n1 -d "sudo ovs-dpctl dump-flows system@ovs-system" > >> > >> recirc_id(0),in_port(2),eth(src=50:54:00:00:00:01,dst=00:00: > 00:00:ff:01),eth_type(0x0806),arp(sip=192.168.0.2,tip=192.16 > 8.0.1,op=1/0xff,sha=50:54:00:00:00:01,tha=00:00:00:00:00:00), > >> packets:0, bytes:0, used:never, > >> actions:userspace(pid=4294958020,slow_path(action)) > >> > >> recirc_id(0),in_port(2),eth(src=50:54:00:00:00:01,dst=00:00: > 00:00:ff:01),eth_type(0x0800),ipv4(src=192.168.0.2,dst=192.1 > 68.0.1,proto=1,ttl=64,frag=no),icmp(type=8,code=0), > >> packets:9, bytes:882, used:0.937s, > >> actions:userspace(pid=4294958021,slow_path(action)) > >> > >> In this case, the ICMP reply is framed by the OVS flow and there is > >> "clone" > >> action involved for the packet to go to and from the logical switch to > >> logical router pipeline. > >> > >> To avoid clone action, I added some code in ovn-northd to respond the > ICMP > >> reply if the ip4.dst = 192.168.0.1 which translated to the below OF flow > >> > >> table=19, n_packets=619, n_bytes=60662, idle_age=1, > >> priority=90,icmp,metadata=0x1,nw_dst=192.168.0.1,icmp_type=8 > ,icmp_code=0 > >> > >> actions=move:NXM_OF_IP_SRC[]->NXM_OF_IP_DST[],mod_nw_src:192 > .168.0.1,push:NXM_OF_ETH_SRC[],push:NXM_OF_ETH_DST[],pop:NXM > _OF_ETH_SRC[],pop:NXM_OF_ETH_DST[],load:0xff->NXM_NX_IP_TTL[ > ],load:0->NXM_OF_ICMP_TYPE[],load:0x1->NXM_NX_REG10[0],resubmit(,20) > >> > >> And in both the cases I see that there is an upcall for each packet and > >> odp_execute_masked_set_action is called. > > > > OK, I think that my suggestion for that patch (patchwork 739796) was > > actually addressing a subtly different issue. > > > > With regards to this issue, as far as I understand back to the > > original report, connection with tuple A is committed to the > > connection tracker. A is then statelessly modified to tuple B, then a > > lookup with B is performed. Typically if you have tuple A or tuple A' > > (ie, the reversed tuple) in the packet headers then looking up with > > either of these headers will find the same connection. If you then > > perform a lookup with tuple B, then it can only look up using B or B'; > > no state was kept about the translation from A->B, so there's no way > > for the connection tracker to associate tuple B back to tuple A. > > Lookup using B and B' cannot find a connection because it was never > > committed like that. Therefore it would be new. However, since B is a > > SYN-ACK packet, the Linux connection tracker considers that it is > > invalid rather than new. For it to work, the tuple B', ie the original > > SYN, should be committed first. > > > > > > Thanks for the explanation. The issue we are seeing is for ICMP packets > and > > looking into the connection tracking entries I see the packet is in > > UNREPLIED state. When the ICMP reply is framed by the ovs flows, the > tuple > > would still remain the same right ? Only ip4.src is swapped with ip4.dst > and > > ICMP code is changed. > > Right, so for ICMP I think the problem is different. Yes, by the looks > only src/dst are swapped and code changed, which should produce a > tuple that can look up and find the original connection. Given that > the execution is happening in userspace, that would be one path to > follow: exactly what is executed upon the packet in terms of datapath > actions after the kernel runs userspace(...,slow_path(action))? Where > is the conntrack call from that path, and how does it try to get the > ct_state from the kernel? > > I wonder if the ICMP issue is related to the patch here: > http://patchwork.ozlabs.org/patch/775756/ > > > Thanks. I will test some more and get back on this. > Hi Joe, I tested the scenario again by adding the below ACLs. All my testing is using the script here - [1] # ACLs for sw0-port1 # - allow all outgoing traffic and related reply traffic # - deny all incoming traffic not a part of an existing connection sudo ovn-nbctl --wait=hv acl-add sw0 from-lport 1001 'inport == "sw0-port1" && ip' allow-related sudo ovn-nbctl --wait=hv acl-add sw0 to-lport 1001 'outport == "sw0-port1" && ip' drop sudo ovn-nbctl acl-list sw0 With the above ACLs, the ping to the router ip is dropped. Below is the output of ovs-dpctl dump-flows sudo ovs-dpctl dump-flows system@ovs-system recirc_id(0x5),in_port(2),ct_state(+new-est-rel-rpl-inv+trk) ,ct_label(0/0x1),eth(src=50:54:00:00:00:01,dst=00:00:00: 00:ff:01),eth_type(0x0800),ipv4(src=192.168.0.2,dst=192.168. 0.1,proto=1,ttl=64,frag=no),icmp(type=8,code=0), packets:119, bytes:11662, used:0.637s, actions:userspace(pid=4294963061,slow_path(action)) recirc_id(0),in_port(2),eth(src=00:00:00:00:00:00/01:00:00: 00:00:00),eth_type(0x0800),ipv4(frag=no), packets:119, bytes:11662, used:0.637s, actions:ct(zone=1),recirc(0x5) recirc_id(0x6),in_port(2),ct_state(+new-est-rel-rpl-inv+trk) ,ct_label(0/0x1),eth_type(0x0800),ipv4(frag=no), packets:119, bytes:11662, used:0.637s, actions:drop I also tested by applying the patch http://patchwork.ozlabs. org/patch/775756/ and I could still see the issue and the datapath flows were same in both the cases. [1] - https://gist.github.com/russellb/4ab0a9641f12f8ac66fdd6822ee7789e This is what I could understand on how ct_state is set and passed between the datapath and userspace - During the upcall, the connection tracking state is passed in the packet metadata in the nl attributes - https://github.com/openvswitch/ovs/blob/master/datapath/conntrack.c#L268 - When the vswitchd sends the packet back to the kernel datapath, it stores the connection tracking state back here - https://github.com/openvswitch/ovs/blob/master/ofproto/ofproto-dpif-upcall.c#L1418 https://github.com/openvswitch/ovs/blob/master/lib/odp-util.c#L4722 Looks like even if vswitchd clears the ct state (using the ct_clear action), it would not be passed back to the kernel datapath - I think even if we implement ct_clear action in datapath, it would not solve the problem. In case if there is an upcall after ct_clear action but before ct commit, the datapath would send the latest ct state back to the userspace making the previous ct_clear action ineffective. Thanks Numan > > Nirman > > > >
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