Re: kseltest: bpf: test_lwt_ip_encap.sh: Why -l used in test_gso

[Liu Yiding <liuyd.fnst@cn.fujitsu.com>]

On 10/14/19 10:29 PM, Prabhakar Kushwaha wrote:
> On 10/14/2019 12:04 PM, Liu Yiding wrote:
>> Hi, Kushwaha.
>>
>>
>> On 10/13/19 9:59 AM, Prabhakar Kushwaha wrote:
>>> Hi All,
>>>
>>> I am trying to understand test_gso test for IPv4 and IPv6 with 
>>> following piece of code
>>>
>>>       # listen on IPv*_DST, capture TCP into $TMPFILE
>>>         if [ "${PROTO}" == "IPv4" ] ; then
>>>                 IP_DST=${IPv4_DST}
>>>                 ip netns exec ${NS3} bash -c \
>>>                        "nc -4 -l -s ${IPv4_DST} -p 9000 > ${TMPFILE} &"
>>>         elif [ "${PROTO}" == "IPv6" ] ; then
>>>                 IP_DST=${IPv6_DST}
>>>                 ip netns exec ${NS3} bash -c \
>>>                        "nc -6 -l -s ${IPv6_DST} -p 9000 > ${TMPFILE} &"
>>>                 RET=$?
>>>         else
>>>                 echo "    test_gso: unknown PROTO: ${PROTO}"
>>>     fi
>>>
>>> I have couple of queries around it
>>>
>>> a) why -l is being used for reading listen on IPv*_DST with -s option.
>>> I was looking at https://www.computerhope.com/unix/nc.htm, following 
>>> has been mentioned:
>>> -l :  Used to specify that nc should listen for an incoming 
>>> connection rather than initiate a connection to a
>>> remote host. It is an error to use this option in conjunction with 
>>> the -p, -s, or -z options.
>>> Additionally, any timeouts specified with the -w option are ignored.
>>>
>>> b) Even if there is requirement of -l option to use. can we provide 
>>> timeout option also. how? as -w dont work with -l.
>>>
>>>
>>> I am facing an issue with Linux-5.3 Kselftest where even if 
>>> test_lwt_ip_encap.sh "exit", bpf/runner.sh is not
>>> running next test case. It just wait until CRTL + c is pressed.
>>
>>
>> I meet same issue. "make run_tests -C bpf" bpf/runner.sh hang on 
>> test_lwt_ip_encap.sh. And when i skip it,
>>
>> test_tc_tunnel.sh also has this problem.
>>
>>
>
> does this means, the problem is independent of "nc" and has no 
> relation with nc usage with -l option.
>
> has anyone find it's root-cause..


I think the root cause is related to kselftest/prefix.pl, you could try 
to kill process prefix.pl, then runner.sh will run next test.


>
> -prabhakar (pk)
>
>
>
>
-- 
Best regards.
Liu Yiding