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<p class="MsoNormal"><span style="font-size:11.0pt">Hi<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">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<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">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<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">We observed that when the ARP reply came back to OVS port it added the following entry<o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt">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</span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">That drop rule states src mac=gateway mac(f0:25:72:ab:d4:c1<b>)</b>, 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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">When we rewrote the packet on TOR to set cos/tos priority to 0 it worked fine.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Question is why does OVS 2.9 add a drop rule when it sees an ARP response with cos/tos priority set to 5.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Has anyone seen this before 2.6 with newton works for this use case and 2.9 with queens fails<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Some info below<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt">L3 Namespace</span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> ip netns exec qrouter-eee032f4-670f-4e43-8e83-e04cb23f00ae ip addr<br>
1: lo: <LOOPBACK,UP,LOWER_UP> mtu <a href="tel:65536">65536</a> qdisc noqueue state UNKNOWN group default qlen <a href="tel:1000">1000</a><br>
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00<br>
inet 127.0.0.1/8 scope host lo<br>
valid_lft forever preferred_lft forever<br>
inet6 ::1/128 scope host <br>
valid_lft forever preferred_lft forever<br>
46: ha-df4ad8aa-18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu <a href="tel:1500">1500</a> qdisc noqueue state UNKNOWN group default qlen <a href="tel:1000">1000</a><br>
link/ether fa:16:3e:eb:0c:21 brd ff:ff:ff:ff:ff:ff<br>
inet <a href="http://169.254.192.5/18">169.254.192.5/18</a> brd <a href="tel:169.254.255.255">169.254.255.255</a> scope global ha-df4ad8aa-18<br>
valid_lft forever preferred_lft forever<br>
inet <a href="http://169.254.0.1/24">169.254.0.1/24</a> scope global ha-df4ad8aa-18<br>
valid_lft forever preferred_lft forever<br>
inet6 fe80::f816:3eff:feeb:c21/64 scope link <br>
valid_lft forever preferred_lft forever<br>
47: qg-e5541f70-a5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu <a href="tel:1500">1500</a> qdisc noqueue state UNKNOWN group default qlen <a href="tel:1000">1000</a><br>
link/ether <b>fa:16:3e:65:85:ad</b> brd ff:ff:ff:ff:ff:ff<br>
inet <a href="http://10.86.67.78/24">10.86.67.78/24</a> scope global qg-e5541f70-a5<br>
valid_lft forever preferred_lft forever<br>
inet6 fe80::f816:3eff:fe65:85ad/64 scope link nodad <br>
valid_lft forever preferred_lft forever<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt"> </span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt">Appctl Trace output</span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">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<br>
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<br>
<br>
bridge("br-int")<br>
----------------<br>
0. in_port=2,vlan_tci=0x0000/0x1fff, priority 3, cookie 0x21589cb48848e7fb<br>
push_vlan:0x8100<br>
set_field:4102->vlan_vid<br>
goto_table:60<br>
60. priority 3, cookie 0x21589cb48848e7fb<br>
NORMAL<br>
-> no learned MAC for destination, flooding<br>
<br>
bridge("br-prov")<br>
-----------------<br>
0. in_port=2, priority 2, cookie 0x7faae4a30960716f<br>
drop<br>
<br>
bridge("br-inst")<br>
-----------------<br>
0. in_port=2, priority 2, cookie 0x8b9b0311aedc1b0c<br>
drop<br>
<br>
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<br>
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<br>
Datapath actions: 9,push_vlan(vid=6,pcp=0),7<br>
ovs_vswitch_15520 [root@BXB-AIO-1 /]# <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt">ovs-dpctl dump-flows</span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">ovs_vswitch_15520 [root@BXB-AIO-1 /]# ovs-dpctl dump-flows | grep f0:25:72:ab:d4:c1<br>
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=<a href="http://10.86.67.1,tip=10.86.67.77,op=1/0xff">10.86.67.1,tip=10.86.67.77,op=1/0xff</a>)), packets:3, bytes:192, used:8.199s,
actions:1<br>
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<br>
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=<a href="http://10.86.67.1,tip=10.86.67.45,op=1/0xff">10.86.67.1,tip=10.86.67.45,op=1/0xff</a>)), packets:3, bytes:192, used:9.778s,
actions:1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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