[pkg-dhcp-devel] Bug#769189: isc-dhcp-client: dhclient -6 -r waits 1m, affecting finish-install on !linux

[Samuel Thibault]

Package: isc-dhcp-client
Version: 4.3.1-5
Severity: important

Hello,

Running

dhclient -6 -r

basically hangs for one minute before returning. Running

dhclient -1 -6 -r

does finish. dhclient.c reads as

        if (release mode) {
#ifndef DHCPv6
                return 0;
#else
                if (local_family == AF_INET6) {
                        if (onetry)
                                return 0;
                } else
                        return 0;
#endif /* DHCPv6 */
        }

I don't really understand why looking for -1 (onetry) in the inet6 case,
I don't see anything in the documentation, and what I understand from
the source code is that in that case, since -r is specified no request
will be sent, and thus no answer will be received, and thus dhclient
will just wait for the timeout (one minute) without doing anything.

This affects d-i's netcfg finish-install script on !linux ports, where
it runs both dhclient -r and dhclient -6 -r. One way to workaround
the issue for now is adding -1 to netcfg.  It happens that it doesn't
hit kfreebsd just because it happens that umount -a in the 95umount
finish-install script manages to kill dhclient for some reason...

Samuel

-- System Information:
Debian Release: jessie/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'buildd-unstable'), (500, 'unstable'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.17.0 (SMP w/8 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages isc-dhcp-client depends on:
ii  debianutils       4.4+b1
ii  iproute2          3.16.0-2
ii  isc-dhcp-common   4.3.1-5
ii  libc6             2.19-12
ii  libdns-export100  1:9.9.5.dfsg-5
ii  libirs-export91   1:9.9.5.dfsg-5
ii  libisc-export95   1:9.9.5.dfsg-5

isc-dhcp-client recommends no packages.

Versions of packages isc-dhcp-client suggests:
pn  avahi-autoipd  <none>
ii  resolvconf     1.76

-- Configuration Files:
/etc/dhcp/dhclient-exit-hooks.d/rfc3442-classless-routes changed [not included]
/etc/dhcp/dhclient.conf changed [not included]

-- no debconf information

-- 
Samuel
Running Windows on a Pentium is like having a brand new Porsche but only
be able to drive backwards with the handbrake on.
(Unknown source)