:: Re: [DNG] ascii an waiting for dhcp…
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Autor: Dr. Nikolaus Klepp
Datum:  
To: dng
Betreff: Re: [DNG] ascii an waiting for dhcp on boot
Am Montag, 18. Dezember 2017 schrieb Didier Kryn:
> Le 18/12/2017 à 09:01, Dr. Nikolaus Klepp a écrit :
> >
> >>>>> Apply this patch to /lib/udev/ifupdown-hotplug-original. It changes line 78 from
> >>>>>     
> >>>>>     exec ifup --allow=hotplug $INTERFACE

> >>>>>
> >>>>> to
> >>>>>
> >>>>>       if [ -z "${INTERFACE##eth[0-9]*}" ]; then
> >>>>>           if [ $(cat /sys/class/net/$INTERFACE/carrier) -eq 1 ]; then
> >>>>>                   exec ifup --allow=hotplug $INTERFACE
> >>>>>           fi
> >>>>>       else
> >>>>>           exec ifup --allow=hotplug $INTERFACE
> >>>>>       fi

> >>>>>
> >>>>>
> >>>>> Which hopefully brings up eth[0-9]* if the cable is plugged in. Most likely it would be a speed improvement if the lines "exec ifup --allow=hotplug $INTERFACE" are changed to "exec ifup --allow=hotplug $INTERFACE &", but this works for me. It won't work if your eth is not called eth[0-9]* :-)
> >>>>>
> >>>>> Nik
> >>>>>
> >>>>>
> >>> Just saw a typo in my mail: the file is "/lib/udev/ifupdown-hotplug" (not "/lib/udev/ifupdown-hotplug-original").
> >>     Now it launches dhclient on eth0 right away, which incurs some
> >> delay before it goes to background. Shorther than before, but still a delay.
> >>
> >>     Didier
> > I think you tried the version without "&" at the end of "exec ifup --allow=hotplug $INTERFACE". Could you please edit the two lines (80 and 83) in "/lib/udev/ifupdown-hotplug" so that they say "exec ifup --allow=hotplug $INTERFACE &" - i.e. add the "&" at the end and try again?
>     I fact, my situation wasn't the same as the one you reported in the
> first place. The message on the console was the following:
>
>     Configure network interfaces...ifup: waiting for lock on
> /run/network/ifstate.eth0
>     This has now disapeared and I am dealing with waiting on DHCP for
> an interface without any cable plugged in.
>
>     I wondered if there was an interplay with ifplugd there.
>
>     I tried disabling all interfaces in ifplugd and the result was the
> same.
>
>     Then I introduced some debug prints in ifupdown-hotplug to debug
> the logic:
> ...
>     printf 'ifupdown-hotplug invoked for interface %s\n' "$INTERFACE"
> >/run/$INTERFACE.log;
>
>     if [ -z "${INTERFACE##eth[0-9]*}" ]; then
>         if [ $(cat /sys/class/net/$INTERFACE/carrier) -eq 1 ]; then
>             printf 'Carrier detected; setting up.\n' >>/run/$INTERFACE.log
>             exec ifup --allow=hotplug $INTERFACE &
>         else
>             printf 'No carrier; do not set up.\n' >>/run/$INTERFACE.log;
>         fi
>     else
>         printf 'Not an ethernet interface; setting up.\n'
> >>/run/$INTERFACE.log;
>         exec ifup --allow=hotplug $INTERFACE &
>     fi
>   ...
>
> The result is as expected:
> $ cat /run/eth0.log
> ifupdown-hotplug invoked for interface eth0
> No carrier; do not set up.
>
>     DHCPDISCOVER is probably launched by the caller of
> ifupdown-hotplug. I tried to exit with return-code 1 in case the carrier
> isn't detected, but this has no effect.
>
>     Didier


Well, yes, that's to expect, but does it also block the boot process? And do you get an IP adress, when, you plug in a cable later?

Nik



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