Re: [PATCH bpf-next v4 1/6] selftests/bpf: Add traffic monitor functions.

[Kui-Feng Lee <sinquersw@gmail.com>]

On 8/1/24 21:35, Kui-Feng Lee wrote:
> 
> 
> On 8/1/24 20:43, Martin KaFai Lau wrote:
>> On 7/31/24 12:31 PM, Kui-Feng Lee wrote:
>>> diff --git a/tools/testing/selftests/bpf/test_progs.h 
>>> b/tools/testing/selftests/bpf/test_progs.h
>>> index cb9d6d46826b..5d4e61fa26a1 100644
>>> --- a/tools/testing/selftests/bpf/test_progs.h
>>> +++ b/tools/testing/selftests/bpf/test_progs.h
>>> @@ -473,4 +473,20 @@ extern void test_loader_fini(struct test_loader 
>>> *tester);
>>>       test_loader_fini(&tester);                           \
>>>   })
>>> +struct tmonitor_ctx;
>>> +
>>> +#ifdef TRAFFIC_MONITOR
>>> +struct tmonitor_ctx *traffic_monitor_start(const char *netns);
>>> +void traffic_monitor_stop(struct tmonitor_ctx *ctx);
>>> +#else
>>> +static inline struct tmonitor_ctx *traffic_monitor_start(const char 
>>> *netns)
>>> +{
>>> +    return (struct tmonitor_ctx *)-1;
>>
>> hmm... from peeking patch 3, only NULL is checked.

When traffic monitor is disable, these two functions are noop.
Returning -1 (not NULL) is convenient for the callers. They don't need
to tell if the error caused by a real error or by the disabled
feature.

>>
>> While at it, if there is no libpcap during make, is the "-m" option 
>> available or the test_progs will error out if "-m" is used?
> 
> "-m" is still available so CI can always pass "-m" without consider
> the configuration of the binary. But, it would be good idea to
> print a warning message for this situation.
> 
>>
>>> +}
>>> +
>>> +static inline void traffic_monitor_stop(struct tmonitor_ctx *ctx)
>>> +{
>>> +}
>>> +#endif
>>> +
>>>   #endif /* __TEST_PROGS_H */
>>