Can you please send the output of tcpdump –x on both interfaces for a few 
seconds when ping is running?

Raja

From: abhishek jain <[email protected]<mailto:[email protected]>>
Date: Wednesday, September 30, 2015 at 10:27 PM
To: Rajagopalan Sivaramakrishnan <[email protected]<mailto:[email protected]>>
Cc: "[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>, 
"[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>
Subject: Re: [opencontrail-dev] Checksum offload error with 
contrail-vrouter-agent running on compute node

Hi Rajagopalan

I captured packets using tcpdump on vhost0 and eth0 on compute node.The 
checksum is correct when capturing packets at vhost0 interface.However the 
checksum incorrect error occurs when I'm capturing packets at eth0 interface of 
the compute node.

Please find the attached screanshot for the same.



On Thu, Oct 1, 2015 at 12:03 AM, Rajagopalan Sivaramakrishnan 
<[email protected]<mailto:[email protected]>> wrote:
Hi Abhishek,
    Can you please run “tcpdump –x” on vhost0 and the physical interface (eth0) 
concurrently and compare the packets to see if anything changed between vhost0 
and eth0 (I.e. after vrouter processed the packet)?

Raja

From: abhishek jain <[email protected]<mailto:[email protected]>>
Date: Wednesday, September 30, 2015 at 8:41 AM
To: Rajagopalan Sivaramakrishnan <[email protected]<mailto:[email protected]>>
Cc: "[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>, 
"[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>

Subject: Re: [opencontrail-dev] Checksum offload error with 
contrail-vrouter-agent running on compute node

Hi Raja

Below are the inline answers for your queries..


Are you seeing any checksum errors go up on the receiver of the ping (using 
netstat)?

The Below fields are incresing at the receiver side when ping is initiated from 
the compute node running contrail-vrouter-agent..


netstat  -s

Ip:
    4666082 total packets received
    4051 with invalid headers
    2 with invalid addresses
    22 forwarded
    0 incoming packets discarded
    4558747 incoming packets delivered
    4493351 requests sent out
    12 outgoing packets dropped
    13 fragments dropped after timeout
    42 reassemblies required
    7 packets reassembled ok
    13 packet reassembles failed
Icmp:
    17279 ICMP messages received
    32 input ICMP message failed.
    ICMP input histogram:
        destination unreachable: 2068
        timeout in transit: 14
        echo requests: 13570
        echo replies: 1627
    17190 ICMP messages sent
    0 ICMP messages failed
    ICMP output histogram:
        destination unreachable: 1776
        redirect: 12
        echo request: 1832
        echo replies: 13570
IcmpMsg:
        InType0: 1627
        InType3: 2068
        InType8: 13570
        InType11: 14
        OutType0: 13570
       OutType3: 1776
        OutType5: 12
        OutType8: 1832
Tcp:
    251330 active connections openings
    127809 passive connection openings
    118574 failed connection attempts
    170 connection resets received
    24 connections established
    3254207 segments received
    3777193 segments send out
    11826 segments retransmited
    144 bad segments received.

The above coloured  field is increasing at the receiver only after ping is 
initiated from the compute node.


Not having the dropstats command on powerpc ubuntu.


When we try to run droptstat command, we got the below prints
#############################################
dropstats

Usage: dropstats [--help]
Usage: dropstats [--core|-c] <core number>

--core <core number>     Show statistics for a specified CPU core
###################################################

Then when we analyse the dropstats.c program, we found that it is getting error 
at the main function itself.

The variable "opt" is not getting any valid values, so the switch case is going 
to the default case and it prints the above prints..

When I print the opt value, it is giving some garbage value itseems,
##################################################
dropstats

OPT VAlue : �
Usage: dropstats [--help]
Usage: dropstats [--core|-c] <core number>

--core <core number>     Show statistics for a specified CPU core
##################################################


Please help us regarding this.

Thanks

On Wed, Sep 30, 2015 at 11:24 AM, Rajagopalan Sivaramakrishnan 
<[email protected]<mailto:[email protected]>> wrote:

>Not having the dropstats command on powerpc ubuntu.

This should be built when you build vrouter utils. If you have “rt” and “nh” 
utilities working, this should work too.

Are you seeing any checksum errors go up on the receiver of the ping (using 
netstat)?

Please check if any counters are going up corresponding to the reception of the 
pings. The absolute values of the counters are not useful.

 netstat -s
Ip:
    621360 total packets received
    1722 with invalid headers
    2 with invalid addresses
    1 forwarded
    0 incoming packets discarded
    596580 incoming packets delivered
    490572 requests sent out
    1 outgoing packets dropped
    3 fragments dropped after timeout
    8 reassemblies required
    1 packets reassembled ok
    3 packet reassembles failed
Icmp:
    5542 ICMP messages received
    10 input ICMP message failed.
    ICMP input histogram:
        destination unreachable: 180
        timeout in transit: 12
        echo requests: 3730
        echo replies: 1620
    5717 ICMP messages sent
    0 ICMP messages failed
    ICMP output histogram:
        destination unreachable: 180
        redirect: 1
        echo request: 1806
        echo replies: 3730
IcmpMsg:
        InType0: 1620
        InType3: 180
        InType8: 3730
        InType11: 12
        OutType0: 3730
        OutType3: 180
        OutType5: 1
        OutType8: 1806
Tcp:
    46413 active connections openings
    23428 passive connection openings
    21350 failed connection attempts
    45 connection resets received
    42 connections established
    434130 segments received
    431999 segments send out
    938 segments retransmited
    32 bad segments received.
    22332 resets sent
Udp:
    182146 packets received
    21 packets to unknown port received.
    0 packet receive errors
    51965 packets sent
UdpLite:
TcpExt:
    24030 TCP sockets finished time wait in fast timer
    2774 delayed acks sent
    Quick ack mode was activated 154 times
    36 packets directly queued to recvmsg prequeue.
    2176 bytes directly received in process context from prequeue
    68980 packet headers predicted
    4 packets header predicted and directly queued to user
    81153 acknowledgments not containing data payload received
    50692 predicted acknowledgments
    20 times recovered from packet loss by selective acknowledgements
    Detected reordering 2 times using SACK
    Detected reordering 6 times using time stamp
    7 congestion windows fully recovered without slow start
    59 congestion windows partially recovered using Hoe heuristic
    1 congestion windows recovered without slow start by DSACK
    309 congestion windows recovered without slow start after partial ack
    20 fast retransmits
    11 forward retransmits
    11 retransmits in slow start
    584 other TCP timeouts
    1 SACK retransmits failed
    212 DSACKs sent for old packets
    29 DSACKs sent for out of order packets
    240 DSACKs received
    272 connections reset due to unexpected data
    22 connections reset due to early user close
    30 connections aborted due to timeout
    TCPDSACKIgnoredOld: 1
    TCPDSACKIgnoredNoUndo: 50
    TCPSackShiftFallback: 198
    IPReversePathFilter: 120
    TCPRcvCoalesce: 15109
    TCPChallengeACK: 37
    TCPSYNChallenge: 32
IpExt:
    InMcastPkts: 57521
    OutMcastPkts: 4516
    InBcastPkts: 54973
    OutBcastPkts: 521
    InOctets: 128287765
    OutOctets: 58739537
    InMcastOctets: 14558645
    OutMcastOctets: 372894
    InBcastOctets: 7484935
    OutBcastOctets: 92175




On Wed, Sep 30, 2015 at 11:08 AM, Rajagopalan Sivaramakrishnan 
<[email protected]<mailto:[email protected]>> wrote:
Hi Abhishek,
   Are you still able to ping when the agent is not running?  Did you try using 
“dropstats" to see if there are any drops inside vrouter?
Are you seeing any checksum errors go up on the receiver of the ping (using 
netstat)?

Raja

From: Dev 
<[email protected]<mailto:[email protected]>> 
on behalf of abhishek jain 
<[email protected]<mailto:[email protected]>>
Date: Tuesday, September 29, 2015 at 10:50 AM
To: "[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>, 
"[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>
Subject: Re: [opencontrail-dev] Checksum offload error with 
contrail-vrouter-agent running on compute node

CCing Omartsyniuk

On Tue, Sep 29, 2015 at 7:36 PM, abhishek jain 
<[email protected]<mailto:[email protected]>> wrote:
Hi Team


We are getting checksum error from the powerpc  ubuntu 32 bit as compute node 
when the contrail-voruter-agent userspace agent is running after ping is 
initiated from the compute node.Please find the attached screanshot for the 
same.We have  disabled checksum offload at both eth0 as well as vhost0 on the 
powerpc ubuntu.

ethtool -K eth0 tx off

ethtool -k vhost0 | grep checksum
rx-checksumming: off [fixed]
tx-checksumming: off
        tx-checksum-ipv4: off [fixed]
        tx-checksum-ip-generic: off [fixed]
        tx-checksum-ipv6: off [fixed]
        tx-checksum-fcoe-crc: off [fixed]
        tx-checksum-sctp: off [fixed]


However still we are not able ping the outside world with 
contrail-vrouter-agent binary running and we are facing same ipv4 checksum 
offload incorrect error when we capture packets after ping is initiated from 
the compute node.

Do we need to make changes in contrail-vrouter-agent code regarding this?


Please help regarding this.
Thanks
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