On 12/17/20 9:23 PM, Yi-Hung Wei wrote:
> On Wed, Dec 16, 2020 at 1:24 AM Ilya Maximets <[email protected]> wrote:
>>
>> On 12/16/20 12:41 AM, Yi-Hung Wei wrote:
>>> On userspace datapath, geneve option flag FLOW_TNL_F_UDPIF should only
>>> be set when the geneve option is available.  However, currently, we always
>>> set FLOW_TNL_F_UDPIF in the metadata flag, and that may result in megaflow
>>> revalidation issue when the geneve option length is zero due to the datapath
>>> flow key mis-match.  That is the original flow key always has 
>>> FLOW_TNL_F_UDPIF
>>> set, while the regenerated flow key during revalidation process  only has
>>> FLOW_TNL_F_UDPIF set if geneve option length is zero.  For reference, check
>>> tun_metadata_to_geneve_nlattr() to see how the flow key of geneve
>>> tunnel metadatafor are generated from netlink attributes.
>>>
>>> The following are the reproducible steps reported by Antonin.
>>> After step 6, OvS reports a warning about failing to update the datapath
>>> flow.
>>>
>>> 2020-12-15T01:56:21.324Z|00007|dpif(revalidator4)|WARN|netdev@ovs-netdev:
>>> failed to put[modify] (No such file or directory)
>>> ufid:d252fe62-5b2a-44e6-846a-190328190e09 skb_priority(0/0),
>>> tunnel(tun_id=0x0,src=192.168.77.1,dst=192.168.77.2,ttl=64/0,tp_src=57391/0,
>>> tp_dst=6081/0,flags(-df-csum+key)),skb_mark(0/0),ct_state(0x21/0x21),
>>> ct_zone(0xfff0/0),ct_mark(0/0),ct_label(0/0),ct_tuple4(src=10.10.0.1/0.0.0.0,
>>> dst=10.10.0.2/0.0.0.0,proto=1/0,tp_src=8/0,tp_dst=0/0),recirc_id(0xa),
>>> dp_hash(0/0),in_port(5),packet_type(ns=0,id=0),
>>> eth(src=1e:9c:f0:fb:18:9c/00:00:00:00:00:00,dst=ee:9f:60:8a:c0:a5/00:00:00:00:00:00),
>>> eth_type(0x0800),ipv4(src=10.10.0.1/0.0.0.0,dst=10.10.0.2,proto=1/0,tos=0/0,
>>> ttl=64/0,frag=no),icmp(type=8/0,code=0/0), actions:drop
>>>
>>> Setup:
>>> 2 Nodes on the same subnet (192.168.77.101/24 - 192.168.77.102/24)
>>>
>>> Step 1 – Creating bridges (run on each Node):
>>>
>>> iface="enp0s8"
>>>
>>> hwaddr=$(ip link show $iface | grep link/ether | awk '{print $2}')
>>> inet=$(ip addr show $iface | grep "inet " | awk '{ print $2 }')
>>>
>>> ovs-vsctl add-br br-phy \
>>>           -- set Bridge br-phy datapath_type=netdev \
>>>           -- br-set-external-id br-phy bridge-id br-phy \
>>>           -- set bridge br-phy fail-mode=standalone \
>>>           other_config:hwaddr="$hwaddr"
>>> ovs-vsctl --timeout 10 add-port br-phy "$iface"
>>> ip addr add "$inet" dev br-phy
>>> ip link set br-phy up
>>> ip addr flush dev enp0s8 2>/dev/null
>>> ip link set enp0s8 up
>>> iptables -F
>>>
>>> ovs-vsctl add-br br-int \
>>>           -- set Bridge br-int datapath_type=netdev \
>>>           -- set bridge br-phy fail-mode=standalone
>>>
>>> Step 2 – Creating netns to for overlay endpoints:
>>>
>>> On first Node (192.168.77.101):
>>> ip netns add ns0
>>> ip link add veth0 type veth peer name veth1
>>> ip link set veth0 netns ns0
>>> ovs-vsctl add-port br-int veth1
>>> ip link set dev veth1 up
>>> ip netns exec ns0 ip addr add 10.10.0.1/24 dev veth0
>>> ip netns exec ns0 ip link set dev veth0 up
>>>
>>> On second Node (192.168.77.102):
>>> ip netns add ns0
>>> ip link add veth0 type veth peer name veth1
>>> ip link set veth0 netns ns0
>>> ovs-vsctl add-port br-int veth1
>>> ip link set dev veth1 up
>>> ip netns exec ns0 ip addr add 10.10.0.2/24 dev veth0
>>> ip netns exec ns0 ip link set dev veth0 up
>>>
>>> Step 3 – Create tunnel (run on each Node):
>>>
>>> ovs-vsctl add-port br-int tun0 -- set interface tun0 type=geneve \
>>> ofport_request=100 options:remote_ip=flow options:key=flow
>>>
>>> Step 4 – Create the following flows:
>>>
>>> On first Node (192.168.77.101):
>>> root@ovs-test-node-1:/home/vagrant# ovs-ofctl dump-flows br-int --no-stats
>>> priority=100,ip actions=resubmit(,10)
>>> priority=0 actions=NORMAL
>>> priority=50 actions=resubmit(,40)
>>> table=10, priority=100,ip actions=ct(table=20,zone=65520)
>>> table=20, priority=200,ct_state=-new+trk,ip actions=resubmit(,30)
>>> table=20, priority=100,ip,nw_dst=10.10.0.2 actions=resubmit(,30)
>>> table=20, priority=0,ip actions=drop
>>> table=30, priority=100,ip actions=ct(commit,table=40,zone=65520)
>>> table=40, priority=100,in_port=veth1 
>>> actions=load:0xc0a84d66->NXM_NX_TUN_IPV4_DST[],output:tun0
>>> table=40, priority=100,in_port=tun0 actions=output:veth1
>>> table=40, priority=0 actions=drop
>>>
>>> On second Node (192.168.77.102):
>>> root@ovs-test-node-2:/home/vagrant# ovs-ofctl dump-flows br-int --no-stats
>>> priority=100,ip actions=resubmit(,10)
>>> priority=0 actions=NORMAL
>>> priority=50 actions=resubmit(,40)
>>> table=10, priority=100,ip actions=ct(table=20,zone=65520)
>>> table=20, priority=200,ct_state=-new+trk,ip actions=resubmit(,30)
>>> table=20, priority=100,ip,nw_dst=10.10.0.2 actions=resubmit(,30)
>>> table=20, priority=0,ip actions=drop
>>> table=30, priority=100,ip actions=ct(commit,table=40,zone=65520)
>>> table=40, priority=100,in_port=veth1 
>>> actions=load:0xc0a84d65->NXM_NX_TUN_IPV4_DST[],output:tun0
>>> table=40, priority=100,in_port=tun0 actions=output:veth1
>>> table=40, priority=0 actions=drop
>>>
>>> Step 5 – Check that ping works:
>>> From the first Node: ip netns exec ns0 ping 10.10.0.2
>>>
>>> Step 6 – The actual issue:
>>> From the first Node: ip netns exec ns0 ping -c 3 10.10.0.2
>>> From the second Node: ovs-ofctl del-flows br-int 
>>> 'table=20,ip,nw_dst=10.10.0.2'
>>> From the first Node: ip netns exec ns0 ping -c 3 10.10.0.2
>>>
>>> Execute these instructions in order, as soon as the previous one
>>> completes.  If you follow these steps, you should see the ping in
>>> the last step succeed.  This is not expected because of the deleted
>>> flow. It also does not happen with VXLAN.
>>>
>>
>> Since you already know how to reproduce the issue, could you, please, create
>> a system test out of these steps or more simplified ones without conntrack?
>>
>> A unit test would be ideal, though.
>>
>> I didn't review the patch itself, but the issue seems not easy to analyze
>> and very easy to re-introduce someday without regression tests.
>>
>> Best regards, Ilya Maximets.
> 
> Thanks William and Ilya for feedback.  WIll work with Toms to add a
> test, then submit the next version.

Hi!  Is there any progress on this patch?
Similar patches are getting submitted to the mail-list:
  
http://patchwork.ozlabs.org/project/openvswitch/patch/[email protected]/

Best regards, Ilya Maximets.
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