Hi
We are seeing a very weird issue with OVS 2.9 which is not seen in OVS 2.6.
Basically the end symptom is from the neutron L3 agent router namespace we
cant ping the gateway in this case 10.86.67.1
Now on performing tcpdump tests we see the gateway responding to ARP the reply
comes into the control/network node and is dropped by OVS in the qg- interface
We observed that when the ARP reply came back to OVS port it added the
following entry
recirc_id(0),in_port(2),eth(src=f0:25:72:ab:d4:c1,dst=fa:16:3e:65:85:ad),eth_type(0x8100),vlan(vid=0),encap(eth_type(0x0806)),
packets:217, bytes:13888, used:0.329s, actions:drop
That drop rule states src mac=gateway mac(f0:25:72:ab:d4:c1), destination
mac=qg-xxx interface drop the packet. We were first not sure why this was
happening but when we inspected the arp response packet from gateway we noticed
in this setup the packet from gatway was sent with cos /tos bit set to priority
5.
When we rewrote the packet on TOR to set cos/tos priority to 0 it worked fine.
Question is why does OVS 2.9 add a drop rule when it sees an ARP response with
cos/tos priority set to 5.
Has anyone seen this before 2.6 with newton works for this use case and 2.9
with queens fails
Some info below
L3 Namespace
ip netns exec qrouter-eee032f4-670f-4e43-8e83-e04cb23f00ae ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536<tel:65536> qdisc noqueue state UNKNOWN
group default qlen 1000<tel:1000>
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
46: ha-df4ad8aa-18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500<tel:1500> qdisc
noqueue state UNKNOWN group default qlen 1000<tel:1000>
link/ether fa:16:3e:eb:0c:21 brd ff:ff:ff:ff:ff:ff
inet 169.254.192.5/18<http://169.254.192.5/18> brd
169.254.255.255<tel:169.254.255.255> scope global ha-df4ad8aa-18
valid_lft forever preferred_lft forever
inet 169.254.0.1/24<http://169.254.0.1/24> scope global ha-df4ad8aa-18
valid_lft forever preferred_lft forever
inet6 fe80::f816:3eff:feeb:c21/64 scope link
valid_lft forever preferred_lft forever
47: qg-e5541f70-a5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500<tel:1500> qdisc
noqueue state UNKNOWN group default qlen 1000<tel:1000>
link/ether fa:16:3e:65:85:ad brd ff:ff:ff:ff:ff:ff
inet 10.86.67.78/24<http://10.86.67.78/24> scope global qg-e5541f70-a5
valid_lft forever preferred_lft forever
inet6 fe80::f816:3eff:fe65:85ad/64 scope link nodad
valid_lft forever preferred_lft forever
Appctl Trace output
ovs_vswitch_15520 [root@BXB-AIO-1 /]# ovs-appctl ofproto/trace br-int
in_port=2,dl_src=f0:25:72:ab:d4:c1,dl_dst=fa:16:3e:65:85:ad
Flow:
in_port=2,vlan_tci=0x0000,dl_src=f0:25:72:ab:d4:c1,dl_dst=fa:16:3e:65:85:ad,dl_type=0x0000
bridge("br-int")
----------------
0. in_port=2,vlan_tci=0x0000/0x1fff, priority 3, cookie 0x21589cb48848e7fb
push_vlan:0x8100
set_field:4102->vlan_vid
goto_table:60
60. priority 3, cookie 0x21589cb48848e7fb
NORMAL
-> no learned MAC for destination, flooding
bridge("br-prov")
-----------------
0. in_port=2, priority 2, cookie 0x7faae4a30960716f
drop
bridge("br-inst")
-----------------
0. in_port=2, priority 2, cookie 0x8b9b0311aedc1b0c
drop
Final flow:
in_port=2,dl_vlan=6,dl_vlan_pcp=0,vlan_tci1=0x0000,dl_src=f0:25:72:ab:d4:c1,dl_dst=fa:16:3e:65:85:ad,dl_type=0x0000
Megaflow:
recirc_id=0,eth,in_port=2,vlan_tci=0x0000/0x1fff,dl_src=f0:25:72:ab:d4:c1,dl_dst=fa:16:3e:65:85:ad,dl_type=0x0000
Datapath actions: 9,push_vlan(vid=6,pcp=0),7
ovs_vswitch_15520 [root@BXB-AIO-1 /]#
ovs-dpctl dump-flows
ovs_vswitch_15520 [root@BXB-AIO-1 /]# ovs-dpctl dump-flows | grep
f0:25:72:ab:d4:c1
recirc_id(0),in_port(2),eth(src=f0:25:72:ab:d4:c1,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8100),vlan(vid=0),encap(eth_type(0x0806),arp(sip=10.86.67.1,tip=10.86.67.77,op=1/0xff<http://10.86.67.1,tip=10.86.67.77,op=1/0xff>)),
packets:3, bytes:192, used:8.199s, actions:1
recirc_id(0),in_port(2),eth(src=f0:25:72:ab:d4:c1,dst=fa:16:3e:65:85:ad),eth_type(0x8100),vlan(vid=0),encap(eth_type(0x0806)),
packets:217, bytes:13888, used:0.329s, actions:drop
recirc_id(0),in_port(2),eth(src=f0:25:72:ab:d4:c1,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8100),vlan(vid=0),encap(eth_type(0x0806),arp(sip=10.86.67.1,tip=10.86.67.45,op=1/0xff<http://10.86.67.1,tip=10.86.67.45,op=1/0xff>)),
packets:3, bytes:192, used:9.778s, actions:1
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