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

Fri May 3 22:02:55 UTC 2019

The thing is, I don’t see empty TCP packet drops on DPDK computes, I nevertheless applied the patch HAN mentioned on DPDK computes, no difference.

The issues we see is on OVS computes.

Jing

From: Darrell Ball <dlu998 at gmail.com>
Sent: Friday, May 03, 2019 3:34 PM
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

On Fri, May 3, 2019 at 10:44 AM Zhang, Jing C. (Nokia - CA/Ottawa) <jing.c.zhang at nokia.com<mailto: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<mailto: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<mailto:jing.c.zhang at nokia.com>>
Cc: Han Zhou <zhouhan at gmail.com<mailto:zhouhan at gmail.com>>; ovs-discuss at openvswitch.org<mailto: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<mailto: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<mailto: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<mailto: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<mailto:jing.c.zhang at nokia.com>>
Cc: Han Zhou <zhouhan at gmail.com<mailto:zhouhan at gmail.com>>; ovs-discuss at openvswitch.org<mailto: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<mailto: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<mailto:dlu998 at gmail.com>>
Sent: Friday, May 3, 2019 12:19 AM
To: Han Zhou <zhouhan at gmail.com<mailto:zhouhan at gmail.com>>; Zhang, Jing C. (Nokia - CA/Ottawa) <jing.c.zhang at nokia.com<mailto:jing.c.zhang at nokia.com>>; ovs-discuss at openvswitch.org<mailto: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<mailto:ovs-discuss-bounces at openvswitch.org>> on behalf of Han Zhou <zhouhan at gmail.com<mailto: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<mailto:jing.c.zhang at nokia.com>>
Cc: "ovs-discuss at openvswitch.org<mailto:ovs-discuss at openvswitch.org>" <ovs-discuss at openvswitch.org<mailto: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<mailto: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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