[ovs-discuss] FW: OVS 2.9.0 native firewall drops empty payload TCP packets continued

Darrell Ball dlu998 at gmail.com
Fri May 3 19:33:32 UTC 2019


On Fri, May 3, 2019 at 10:44 AM Zhang, Jing C. (Nokia - CA/Ottawa) <
jing.c.zhang at nokia.com> wrote:

>
>    1. The hybrid firewall refers to Linux bridge based firewall. To debug
>    the issue, we switch the neutron OVS agent to use native firewall.
>
>
>
> [securitygroup]
>
> #firewall_driver=iptables_hybrid
>
> firewall_driver=openvswitch
>
>
>
> # ovs-ofctl dump-flows br-int | grep ct_state
>
> cookie=0xddb977285e2ba9b6, duration=185.322s, table=71, n_packets=0,
> n_bytes=0, idle_age=185, priority=110,ct_state=+trk
> actions=ct_clear,resubmit(,71)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=0,
> n_bytes=0, idle_age=184, priority=75,ct_state=+est-rel-rpl,icmp,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=204,
> n_bytes=16642, idle_age=18, priority=77,ct_state=+est-rel-rpl,udp,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=0,
> n_bytes=0, idle_age=184, priority=77,ct_state=+est-rel-rpl,tcp,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=0,
> n_bytes=0, idle_age=184, priority=75,ct_state=+new-est,icmp,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=204,
> n_bytes=16642, idle_age=18, priority=77,ct_state=+new-est,udp,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=0,
> n_bytes=0, idle_age=184, priority=77,ct_state=+new-est,tcp,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=0,
> n_bytes=0, idle_age=184, priority=74,ct_state=+est-rel-rpl,ipv6,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=0,
> n_bytes=0, idle_age=184, priority=74,ct_state=+est-rel-rpl,ip,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=0,
> n_bytes=0, idle_age=184, priority=74,ct_state=+new-est,ipv6,reg5=0x1
> actions=resubmit(,73)
>
> cookie=0xddb977285e2ba9b6, duration=182.170s, table=72, n_packets=0,
> n_bytes=0, idle_age=184, priority=74,ct_state=+new-est,ip,reg5=0x1
> actions=resubmit(,73)
>
>
>
> My understanding is Centos 7 packs the OVS tree, that how conntrack is
> supported before kernel 4.3.
>
>
>
> https://cbs.centos.org/koji/buildinfo?buildID=24381
>

I assumed you are using Linux tree OVS kernel module



>
>
>
>
>    1. I back-ported the patch pointed by Han to OVS v2.9.0, it does not
>    solve the packet drop on the OVS compute.
>
>
Thanks for confirming
We don't know your full topology, but if you want to send packets following
a path that goes thru an OVS userspace datapath then
that patch would be applicable.
Did you apply the patch to ALL userspace dataspath instances that could be
in you packet path ?
What is the path followed in the problem case ?



>
>    1.
>
>
>
> The nature of the issue is same, OVS native firewall drops packets less
> than 60 bytes.
>
>
>
> Pls correct me and advise if the issue on OVS compute is fixable.
>

You could check the OVS tree kernel module.



>
>
> JIng
>
>
>
> *From:* Darrell Ball <dlu998 at gmail.com>
> *Sent:* Friday, May 3, 2019 11:55 AM
> *To:* Zhang, Jing C. (Nokia - CA/Ottawa) <jing.c.zhang at nokia.com>
> *Cc:* Han Zhou <zhouhan at gmail.com>; ovs-discuss at openvswitch.org
> *Subject:* Re: FW: [ovs-discuss] OVS 2.9.0 native firewall drops empty
> payload TCP packets continued
>
>
>
> couple corrections inline
>
>
>
> On Fri, May 3, 2019 at 8:52 AM Darrell Ball <dlu998 at gmail.com> wrote:
>
>
>
>
>
> On Fri, May 3, 2019 at 8:29 AM Zhang, Jing C. (Nokia - CA/Ottawa) <
> jing.c.zhang at nokia.com> wrote:
>
>
>    1. This issue is with native OVS firewall where the data flows are
>    subject to conntrack rules, there is no issue for hybrid firewall
>
>
>
> 1/ Does 'native OVS firewall' mean either kernel datapath or userpace
> datapath ?
>
> 2/ Pls define 'hybrid datapath' in your context ?
>
>
>
> 2/ Pls define 'hybrid firewall' in your context ?
>
>
>
>
>
>
>    1.
>
>
>
>    1. Below is from DPDK compute:
>
>
>
> # ovs-vsctl --no-wait get Open_vSwitch . other_config
>
>
>
> 3/ dpdk is not initialized
>
>
>
> An info log is also present when dpdk is initialized: "DPDK Enabled -
> initialized"
>
>
>
> btw: '--no-wait' is needed for get commands
>
>
>
> btw: '--no-wait' is NOT needed for get commands
>
>
>
>
>
>
>
> # ovs-vsctl -- list bridge br-int | grep datapath
>
> datapath_id         : "00001a9b5b9ec94e"
>
> datapath_type       : netdev
>
> datapath_version    : "<built-in>"
>
>
>
> 4/ You are using userspace datapath on this particular node without dpdk
> support
>
>     Is that intentional ?
>
>
>
>
>
>
>
> *From:* Darrell Ball <dlu998 at gmail.com>
> *Sent:* Friday, May 3, 2019 11:24 AM
> *To:* Zhang, Jing C. (Nokia - CA/Ottawa) <jing.c.zhang at nokia.com>
> *Cc:* Han Zhou <zhouhan at gmail.com>; ovs-discuss at openvswitch.org
> *Subject:* Re: FW: [ovs-discuss] OVS 2.9.0 native firewall drops empty
> payload TCP packets continued
>
>
>
> The node you are displaying below is running kernel datapath
>
>
>
> fyi: The fix Han pointed you to is for userspace datapath/conntrack
>
>
>
>
>
>
>
> On Fri, May 3, 2019 at 8:14 AM Zhang, Jing C. (Nokia - CA/Ottawa) <
> jing.c.zhang at nokia.com> wrote:
>
> We have both OVS and OVS-dpdk computes.
>
>
>
> Below is from OVS compute:
>
>
>
> # ovs-vsctl --no-wait get Open_vSwitch . other_config
>
> {}
>
> # ovs-vsctl -- list bridge br-int | grep datapath
>
> datapath_id         : "0000aaf62aaf3546"
>
> datapath_type       : system
>
> datapath_version    : "<unknown>"
>
>
>
> *From:* Darrell Ball <dlu998 at gmail.com>
> *Sent:* Friday, May 3, 2019 12:19 AM
> *To:* Han Zhou <zhouhan at gmail.com>; Zhang, Jing C. (Nokia - CA/Ottawa) <
> jing.c.zhang at nokia.com>; ovs-discuss at openvswitch.org
> *Subject:* Re: FW: [ovs-discuss] OVS 2.9.0 native firewall drops empty
> payload TCP packets continued
>
>
>
> What do the following commands yield ?
>
>
>
> sudo ovs-vsctl -- get bridge <bridge name> datapath_type
>
>
>
> sudo ovs-vsctl --no-wait get Open_vSwitch . other_config
>
>
>
>
>
>
>
> *From: *<ovs-discuss-bounces at openvswitch.org> on behalf of Han Zhou <
> zhouhan at gmail.com>
> *Date: *Thursday, May 2, 2019 at 7:12 PM
> *To: *"Zhang, Jing C. (Nokia - CA/Ottawa)" <jing.c.zhang at nokia.com>
> *Cc: *"ovs-discuss at openvswitch.org" <ovs-discuss at openvswitch.org>
> *Subject: *Re: [ovs-discuss] OVS 2.9.0 native firewall drops empty
> payload TCP packets continued
>
>
>
>
>
> On Thu, May 2, 2019 at 6:04 PM Zhang, Jing C. (Nokia - CA/Ottawa) <
> jing.c.zhang at nokia.com> wrote:
> >
> > We (our VNFs) continue to observe the same empty payload TCP (ACK)
> packet drop with native firewall (see original post below) after upgrading
> to Centos 7.6. This packet drop results in unacceptable TCP performance, by
> that native firewall still can not be enabled in product.
> >
> >
> https://mail.openvswitch.org/pipermail/ovs-discuss/2018-August/047263.html
> <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.openvswitch.org%2Fpipermail%2Fovs-discuss%2F2018-August%2F047263.html&data=02%7C01%7Cdball%40vmware.com%7Cd358d5a23b2640ebd28708d6cf6cc524%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C0%7C0%7C636924463524642583&sdata=ihTE%2BcOA9d8yNflCbqJYHXOJWhFuqvq4yJmu7H9lGwo%3D&reserved=0>
> >
> > $ uname -a
> > Linux overcloud-sriovperformancecompute-0 3.10.0-957.10.1.el7.x86_64 #1
> SMP Mon Mar 18 15:06:45 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
> >
> > $ ovs-vswitchd --version
> > ovs-vswitchd (Open vSwitch) 2.9.0
> > DPDK 17.11.0
> >
> > The scenario: OVS provider VLAN network is used
> >
> >
> > in physical interface of ovs compute zero length tcp payload packet
> arrives as padded to 64 bytes (and vlan tag is included in ethernet header)
> > same packet does not appear anymore in the tcpdump taken from tap-xyz
> interface (once vlan tag is removed and packet is cut by 4 bytes to 60
> bytes)
> >
> >
> > Tcpdump on physical port:
> >
> > 00:25:24.468423 fa:16:3e:d7:bb:2c > fa:16:3e:ff:dd:29, ethertype 802.1Q
> (0x8100), length 2674: vlan 3837, p 0, ethertype IPv4, (tos 0x0, ttl 64, id
> 6893, offset 0, flags [DF], proto TCP (6), length 2656)
> >     192.168.10.52.80 > 192.168.10.60.57576: Flags [P.], cksum 0xa013
> (incorrect -> 0x772d), seq 8961:11577, ack 78, win 210, length 2616: HTTP
> > 00:25:24.468593 fa:16:3e:ff:dd:29 > fa:16:3e:d7:bb:2c, ethertype 802.1Q
> (0x8100), length 60: vlan 3837, p 0, ethertype IPv4, (tos 0x0, ttl 64, id
> 56318, offset 0, flags [DF], proto TCP (6), length 40)
> >     192.168.10.60.57576 > 192.168.10.52.80: Flags [.], cksum 0x1d34
> (correct), seq 78, ack 11577, win 391, length 0
> > 00:25:24.475848 fa:16:3e:ff:dd:29 > fa:16:3e:d7:bb:2c, ethertype 802.1Q
> (0x8100), length 60: vlan 3837, p 0, ethertype IPv4, (tos 0x0, ttl 64, id
> 56319, offset 0, flags [DF], proto TCP (6), length 40)
> >     192.168.10.60.57576 > 192.168.10.52.80: Flags [F.], cksum 0x1d33
> (correct), seq 78, ack 11577, win 391, length 0
> > 00:25:24.480337 fa:16:3e:d7:bb:2c > fa:16:3e:ff:dd:29, ethertype 802.1Q
> (0x8100), length 2674: vlan 3837, p 0, ethertype IPv4, (tos 0x0, ttl 64, id
> 6894, offset 0, flags [DF], proto TCP (6), length 2656)
> >     192.168.10.52.80 > 192.168.10.60.57576: Flags [P.], cksum 0xa013
> (incorrect -> 0x772d), seq 8961:11577, ack 78, win 210, length 2616: HTTP
> >
> > Tcpdump on vm tap interface:
> >
> > 00:25:24.468419 fa:16:3e:d7:bb:2c > fa:16:3e:ff:dd:29, ethertype IPv4
> (0x0800), length 2670: (tos 0x0, ttl 64, id 6893, offset 0, flags [DF],
> proto TCP (6), length 2656)
> >     192.168.10.52.80 > 192.168.10.60.57576: Flags [P.], cksum 0xa013
> (incorrect -> 0x772d), seq 8961:11577, ack 78, win 210, length 2616: HTTP
> > 00:25:24.480331 fa:16:3e:d7:bb:2c > fa:16:3e:ff:dd:29, ethertype IPv4
> (0x0800), length 2670: (tos 0x0, ttl 64, id 6894, offset 0, flags [DF],
> proto TCP (6), length 2656)
> >     192.168.10.52.80 > 192.168.10.60.57576: Flags [P.], cksum 0xa013
> (incorrect -> 0x772d), seq 8961:11577, ack 78, win 210, length 2616: HTTP
> >
> > Very straightforward to see the issue:
> >
> >
> > Configure neutron OVS agent to use native firewall
> > Create a pair of VMs on separate computes on provider vLAN
> > Disable TCP timestamp inside the VMs
> > Exchange TCP traffic between the VMs, e.g. http download.
> > Tcpdump on the physical and vm port, and compare.
> >
> >
> > I wonder why such obvious issue is not widely discussed?
> >
> > Jing
> >
>
>
>
> Maybe it's fixed by:
>
>
> https://github.com/openvswitch/ovs/commit/9171c63532ee9cbc63bb8cfae364ab071f44389b
> <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fopenvswitch%2Fovs%2Fcommit%2F9171c63532ee9cbc63bb8cfae364ab071f44389b&data=02%7C01%7Cdball%40vmware.com%7Cd358d5a23b2640ebd28708d6cf6cc524%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C0%7C0%7C636924463524652585&sdata=OLr263fKPdgKA5nga2UlGNF0WtB6srXSIg9a7aHkf44%3D&reserved=0>
>
>
>
>
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