[ovs-discuss] Behavior of netdev (dpdk) bridges with non-dpdkvhostuser ports

Chandran, Sugesh sugesh.chandran at intel.com
Tue Oct 11 08:45:58 UTC 2016


Hi Geza,

Regards
_Sugesh

From: discuss [mailto:discuss-bounces at openvswitch.org] On Behalf Of Geza Gemes
Sent: Sunday, October 9, 2016 5:30 PM
To: discuss at openvswitch.org
Subject: [ovs-discuss] Behavior of netdev (dpdk) bridges with non-dpdkvhostuser ports


Hi,

I've created a libvirt/KVM VM  with Ubuntu 16.04 for experimenting with OVS 2.6 and DPDK 16.07 (from ubuntu cloud archive, newton), it has a number of NICs, out of which I've kept one for a kernel (ens16) and one for a DPDK (dpdk0) datapath.
The bridge setup without virtual NICs:
#ovs-vsctl show
ef015869-3f47-45d4-af20-644f75208a92
    Bridge "dpdk-br0"
        Port "dpdk-br0"
            Interface "dpdk-br0"
                type: internal
        Port "dpdk0"
            Interface "dpdk0"
                type: dpdk
    Bridge "non-dpdk-br1"
        Port "ens16"
            Interface "ens16"
        Port "non-dpdk-br1"
            Interface "non-dpdk-br1"
                type: internal
    ovs_version: "2.6.0"
I've created an lxc container (I'm using the lxc daily ppa) with the following config:
# grep -v ^# /var/lib/lxc/ovsdpdkbr/config

lxc.include = /usr/share/lxc/config/ubuntu.common.conf

lxc.rootfs = /var/lib/lxc/ovsdpdkbr/rootfs
lxc.rootfs.backend = dir
lxc.utsname = ovsdpdkbr
lxc.arch = amd64

lxc.network.type = veth
lxc.network.link = dpdk-br0
lxc.network.flags = up
lxc.network.hwaddr = 00:16:3e:0c:c3:69
lxc.network.veth.pair = veth-dpdk

Started the lxc container and expected to have no connectivity as lxc is not aware of the bridge being netdev:

# ovs-vsctl show
ef015869-3f47-45d4-af20-644f75208a92
    Bridge "dpdk-br0"
        Port "dpdk-br0"
            Interface "dpdk-br0"
                type: internal
        Port veth-dpdk
            Interface veth-dpdk
        Port "dpdk0"
            Interface "dpdk0"
                type: dpdk
    Bridge "non-dpdk-br1"
        Port "ens16"
            Interface "ens16"
        Port "non-dpdk-br1"
            Interface "non-dpdk-br1"
                type: internal
    ovs_version: "2.6.0"

The strange thing is, that it has got an IP address over eth0:
$ ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:16:3e:0c:c3:69
          inet addr:192.168.122.215  Bcast:192.168.122.255  Mask:255.255.255.0
          inet6 addr: fe80::216:3eff:fe0c:c369/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:17 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2768 (2.7 KB)  TX bytes:1374 (1.3 KB)
 and is able to ping the host:
ubuntu at ovsdpdkbr:~$ ping -c 1 192.168.122.1
PING 192.168.122.1 (192.168.122.1) 56(84) bytes of data.
64 bytes from 192.168.122.1<http://192.168.122.1>: icmp_seq=1 ttl=64 time=0.290 ms

--- 192.168.122.1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.290/0.290/0.290/0.000 ms

And the host is also able to ping the container:
$ ping -c 1 192.168.122.215
PING 192.168.122.215 (192.168.122.215) 56(84) bytes of data.
64 bytes from 192.168.122.215<http://192.168.122.215>: icmp_seq=1 ttl=64 time=0.265 ms

--- 192.168.122.215 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.265/0.265/0.265/0.000 ms

But while sshd listens in the container:
root at ovsdpdkbr:~# netstat -tunap
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:22<http://0.0.0.0:22>              0.0.0.0:*               LISTEN      179/sshd
tcp6       0      0 :::22                   :::*                    LISTEN      179/sshd
udp        0      0 0.0.0.0:68<http://0.0.0.0:68>              0.0.0.0:*                           147/dhclient

I cannot connect to it from the host:
ssh -v -v -v ubuntu at 192.168.122.215<mailto:ubuntu at 192.168.122.215>
OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
debug1: Reading configuration data /home/egzagme/.ssh/config
debug1: /home/egzagme/.ssh/config line 1: Applying options for 192.168.*.*
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.122.215 [192.168.122.215] port 22.

Looks like ICMP and UDP packets go through somehow, but TCP does not.
[Sugesh] Did you configure any static rules or its just normal action in OVS?
Can you please confirm what rules are being installed in the OVS datapath?
Have you tried ssh in container with different port than 22?
Also is there any iptable rules that present in the host?



Could someone please explain the observed behavior?

Thank you in advance!

Cheers,

Geza
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