[ovs-discuss] OVS

[Gregory Rose]

On 3/25/2019 9:03 AM, Gregory Rose wrote:
>
> On 3/23/2019 2:28 AM, Ammu wrote:
>> Hey Greg,
>>
>> The recent check with OVS 2.10.1 version was done with CentOS Linux 
>> release 7.3.1611
>>
>> But, I will have to support the solution with distributions 
>> CentOS/Red Hat/Ubuntu.
>>
>> Currently giving you the output of distribution CentOS alone.
>>
>> [root at localhost ~]# modinfo openvswitch
>> filename: 
>>  /lib/modules/3.10.0-514.el7.x86_64/kernel/net/openvswitch/openvswitch.ko
>> license:        GPL
>> description:    Open vSwitch switching datapath
>> rhelversion:    7.3
>> srcversion:     B31AE95554C9D9A0067F935
>> depends: 
>> nf_conntrack,nf_nat,libcrc32c,nf_nat_ipv6,nf_nat_ipv4,nf_defrag_ipv6
>> intree:         Y
>> vermagic:       3.10.0-514.el7.x86_64 SMP mod_unload modversions
>> signer:         CentOS Linux kernel signing key
>> sig_key: D4:88:63:A7:C1:6F:CC:27:41:23:E6:29:8F:74:F0:57:AF:19:FC:54
>> sig_hashalgo:   sha256
>
> OK, I wanted to make sure that's the case before I do the repro 
> attempt today.  I'm using a 7.5 based
> driver but it should be substantially the same.  I'll update in a bit 
> after I try it out.
>

Hi Ammu,

I have tried your setup but am not seeing the same results.

Here is my configuration on machine A:

[root at localhost ovs-test-scripts]# ovs-vsctl show
a83453d5-27f8-4873-9356-e94b0d488797
     Bridge "br0"
         Port "vxlan1"
             Interface "vxlan1"
                 type: vxlan
                 options: {df_default="false", key="100", 
remote_ip="200.0.0.102"}
         Port "br0"
             Interface "br0"
                 type: internal
     ovs_version: "2.10.1"

I have the identical configuration on Machine B, with the tunnel 
pointing back
to machine A:

[root at localhost ovs-test-scripts]# ovs-vsctl show
bd184ee4-6e36-415b-ab90-e447046470c9
     Bridge "br0"
         Port "vxlan1"
             Interface "vxlan1"
                 type: vxlan
                 options: {df_default="false", key="100", 
remote_ip="200.0.0.109"}
         Port "br0"
             Interface "br0"
                 type: internal
     ovs_version: "2.10.1"

Both machines are running RHEL 7.5 which should be equivalent to CentOS 7.5.

I ran an iperf session and captured the first 500 packets.  I have 
attached the
packet capture file.

On Frame # 4 below we see the outer IPv4 header does not have the DF bit 
set on the
outer IPv4 UDP encapsulating frame.

Frame 4: 1514 bytes on wire (12112 bits), 1514 bytes captured (12112 bits)
Ethernet II, Src: RealtekU_a3:69:97 (52:54:00:a3:69:97), Dst: 
RealtekU_3a:a4:cd (52:54:00:3a:a4:cd)
Internet Protocol Version 4, Src: 200.0.0.102, Dst: 200.0.0.109
     0100 .... = Version: 4
     .... 0101 = Header Length: 20 bytes (5)
     Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
     Total Length: 1500
     Identification: 0xd87c (55420)
     Flags: 0x0000
         0... .... .... .... = Reserved bit: Not set
         .0.. .... .... .... = Don't fragment: Not set <--------------- 
not set
         ..0. .... .... .... = More fragments: Not set
         ...0 0000 0000 0000 = Fragment offset: 0
     Time to live: 64
     Protocol: UDP (17)
     Header checksum: 0x0bc1 [validation disabled]
     [Header checksum status: Unverified]
     Source: 200.0.0.102
     Destination: 200.0.0.109
User Datagram Protocol, Src Port: 34290, Dst Port: 4789
     Source Port: 34290
     Destination Port: 4789
     Length: 1480
     [Checksum: [missing]]
     [Checksum Status: Not present]
     [Stream index: 2]

CentOS 7.3 is pretty old - could you try upgrading to Centos 7.5 or 
higher and then
see if the issue is resolved?  Or is there perhaps some step you're 
doing that I'm
missing?

Here is my modinfo for openvswitch:
filename: 
/lib/modules/3.10.0-862.el7.x86_64/kernel/net/openvswitch/openvswitch.ko.xz
alias:          net-pf-16-proto-16-family-ovs_packet
alias:          net-pf-16-proto-16-family-ovs_flow
alias:          net-pf-16-proto-16-family-ovs_vport
alias:          net-pf-16-proto-16-family-ovs_datapath
license:        GPL
description:    Open vSwitch switching datapath
retpoline:      Y
rhelversion:    7.5
srcversion:     E70A19E64B8AC42B9A7641F
depends: 
nf_conntrack,nf_nat,libcrc32c,nf_nat_ipv6,nf_nat_ipv4,nf_defrag_ipv6
intree:         Y
vermagic:       3.10.0-862.el7.x86_64 SMP mod_unload modversions
signer:         Red Hat Enterprise Linux kernel signing key
sig_key: 51:73:02:3B:F8:16:37:D7:BF:3C:51:50:13:4E:EC:84:1B:96:FD:0B
sig_hashalgo:   sha256

Thanks,

- Greg

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