Package: isc-dhcp-client
Version: 4.3.1-6+deb8u4
Severity: important
Tags: ipv6
Requesting an address with dhclient over dhcp6 does not always set the ipv6
prefix length
right. The address received seems always to get a /128 prefix set, even if the
dhcp6 server
sends another one.
I would expect dhclient to set the prefix lenght, if the dhcp6 server sends one.
The code in /sbin/dhclient-script under the relevant section "### DHCPv6
Handlers" is the
same in Devuan Jessie, where I used reportbug to write this bug, Debian Stretch
(4.3.5-3+deb9u1)
and in Debian Sid (4.4.1-2.1+b2).
In the code that does set the ipv6 address using iproute2 there is no prefix
mentioned at all.
See line 385 and the following:
385 BOUND6|RENEW6|REBIND6)
386 if [ "${new_ip6_address}" ]; then
387 # set leased IP
388 ip -6 addr add ${new_ip6_address} \
389 dev ${interface} scope global
390 fi
It could be that /sbin/dhclient should set the prefix to the address, I don't
know.
This part has two problems: It should also be called upon reason REBOOT6 (see
man dhclient-script(8))
and it should set the prefix if one was given (and not already present with the
address). Something
like the following would help:
385 BOUND6|RENEW6|REBIND6|REBOOT6)
386 if [ "${new_ip6_address}" ]; then
387
388 # check wether a prefix was passed and add it to the address
389 if [ -n "$new_ip6_prefixlen" ]; then
390
new_ip6_address_and_prefix="${new_ip6_address}/${new_ip6_prefixlen}"
391 else
392 new_ip6_address_and_prefix="${new_ip6_address}"
393 fi
394
395 # set leased IP
396 ip -6 addr add ${new_ip6_address_and_prefix} \
397 dev ${interface} scope global
398 fi
What really confuses me, is that ISC did change the IPv6 handling in the
dhclient-script, but it is not
brought to Debian. In the upstream version they call a function
"add_ipv6_addr_with_DAD". So I guess, the
bug is not present there. If I watch at the source package of 4.4.1-2.1, I do
see the upstream changes, but
they are not present in the script that the binary package of 4.4.1-2.1+b2
delivers. Sorry, I don't
understand what's going on here.
Thank you for your help.
Regards, Adrian.
-- System Information:
Debian Release: 7.11
Architecture: amd64 (x86_64)
Kernel: Linux 3.16.0-10-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: sysvinit (via /sbin/init)
Versions of packages isc-dhcp-client depends on:
ii debianutils 4.4+b1
ii iproute2 3.16.0-2
ii isc-dhcp-common 4.3.1-6+deb8u4
ii libc6 2.19-18+deb8u10
ii libdns-export100 1:9.9.5.dfsg-9+deb8u18
ii libirs-export91 1:9.9.5.dfsg-9+deb8u18
ii libisc-export95 1:9.9.5.dfsg-9+deb8u18
isc-dhcp-client recommends no packages.
Versions of packages isc-dhcp-client suggests:
pn avahi-autoipd <none>
pn resolvconf <none>
-- no debconf information
