Am Montag, 18. Dezember 2017 schrieb Didier Kryn:
> Le 18/12/2017 à 11:42, Dr. Nikolaus Klepp a écrit :
> > 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?
> With ifplugd uninstalled, I get an ipv6 address on eth0 when I plug
> a cable. This address persists after the cable is removed. After
> re-installing ifplugd, as expected, I need to ifup/ifdown eth0 for the
> situation to change and I get IPV6 and IPV4 addresses on eth0.
>
> I'm not sure I understand well what's happening with this network
> initialization, but don't you think the most logical place to check for
> carrier presence is just where dhclient is invoked?
>
> Didier
Hi!
That is a good question. I think dhclient should not be called, when no cable
is present. Looks like ifplugd is of different opinion. When I read the sources
of ifplugd correctly, then the package installes a file "ifplugd.action". In
this file line 27 says:
[ "$2" = "up" ] && exec /sbin/ifup $1
Now change this line to
if [ -z "${1##eth[0-9]*}" ]; then
if [ $(cat /sys/class/net/$1/carrier) -eq 1 ]; then
exec /sbin/ifup $1
fi
fi
Please try this (hope I have no typo).
Nik
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