Re: Should the tcpdump tests be run with TZ=GMT0, or should the AFS printer print time stamps in UTC?

[Francois-Xavier Le Bail <devel.fx.lebail () orange fr>]

On 06/08/2018 17:17, Francois-Xavier Le Bail wrote:
> On 06/08/2018 15:09, Francois-Xavier Le Bail wrote:
> > On 06/08/2018 14:52, Francois-Xavier Le Bail wrote:
> > > On 06/08/2018 10:42, Denis Ovsienko wrote:
> > > >  ---- On Sun, 05 Aug 2018 18:21:47 +0100 John Hawkinson <jhawk () MIT EDU> wrote ---- 
> > > >  > Denis Ovsienko <denis () ovsienko info> wrote on Sun,  5 Aug 2018 
> > > >  > at 17:05:20 +0100 in <1650ad5fd29.b5d2798f311917.536858429581803402 () ovsienko info>: 
> > > >  > > I understand what you are suggesting, and your description is 
> > > >  > > correct, but it does not solve the problem of interpreting tcpdump 
> > > >  > > output correctly in a place or time different from the 
> > > >  > > original. That said, I can live with print-rx.c using local time and 
> > > >  > > being imperfect, it has worked like this many years. Still, I think 
> > > >  > > local time should not be the norm for other decoders. 
> > > >  >  
> > > >  > Doesn't this argument apply for other decoders as well? Whatever is done should not make the output of decoders 
> > > > harder for the diagnostic users of tcpdump to interpret, or unnecessarily change the output format. 
> > > >
> > > > The factor of consistency does indeed apply, and some decoders use UTC already, whilst some others seem to use 
> > > > local time and to fail the tests from time to time.
> > >
> > > > Which reminds us that at the end of the day somebody will need to fix the AFS test, whatever is the consensus.
> > >
> > > With the rx packet (#4 in the file) showing the problem, in the current printing (CEST),
> > > the capture time is '23:46:24' and the StoreStatus date is '22:46:24'. difference -1 hour.
> > > And with TZ=GMT0,
> > > The capture time is '21:46:24' (-2: OK) and the StoreStatus date is '21:46:24' (-1). same.
> > >
> > > Does anyone understand why?
> > > ---------------------------------------------------------------------------------------------------
> > > $ ./tcpdump -#ttttnv -r tests/afs.pcap|grep -B1 'StoreStatus date'
> > > reading from file tests/afs.pcap, link-type EN10MB (Ethernet)
> > >     4  1999-11-11 23:46:24.151512 IP (tos 0x0, ttl 64, id 57928, offset 0, flags [none], proto UDP
> > > (17), length 108)
> > >     131.151.32.21.7001 > 131.151.1.59.7000:  rx data seq 1 ser 433 fs call makedir fid 536871098/1/1
> > > "tmpdir" StoreStatus date 1999/11/11 22:46:24 group 0 mode 755 (80)
> > > ---------------------------------------------------------------------------------------------------
> > > $ TZ=GMT0 ./tcpdump -#ttttnv -r tests/afs.pcap|grep -B1 'StoreStatus date'
> > > reading from file tests/afs.pcap, link-type EN10MB (Ethernet)
> > >     4  1999-11-11 21:46:24.151512 IP (tos 0x0, ttl 64, id 57928, offset 0, flags [none], proto UDP
> > > (17), length 108)
> > >     131.151.32.21.7001 > 131.151.1.59.7000:  rx data seq 1 ser 433 fs call makedir fid 536871098/1/1
> > > "tmpdir" StoreStatus date 1999/11/11 21:46:24 group 0 mode 755 (80)
> >
> > Perhaps a 'Daylight saving time' reason ... Not sure.
>
> Seems a need to reworking printing time in util-print.c. I am looking at it.

Daylight saving time problem confirmed. Update needed. I am working on it.

-- 
Francois-Xavier
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