[Bug 1633479] Re: dhclient does not wait for ipv6 dad (duplicate address detection)

[Scott Moser]

I can also confirm trusty and precise as shown above.
They behave differently, in that instead of exiting failure, dhclient actually tries again and ends up getting an address. So in precise you would see: 


| # dhclient -6 -1 -v $dev
| Internet Systems Consortium DHCP Client 4.1-ESV-R4
| Copyright 2004-2011 Internet Systems Consortium.
| All rights reserved.
| For info, please visit https://www.isc.org/software/dhcp/
| 
| Bound to *:546
| Listening on Socket/eth0
| Sending on   Socket/eth0
| PRC: Confirming active lease (INIT-REBOOT).
| 
| XMT: Forming Confirm, 0 ms elapsed.
| XMT:  X-- IA_NA 3e:28:e6:37
| XMT:  | X-- Confirm Address fd42:198e:d2a5:1d10:1e4c:ac80:7f2e:f59e
| XMT:  V IA_NA appended.
| XMT: Confirm on eth0, interval 920ms.
| send_packet6: Cannot assign requested address
| dhc6: sendpacket6() sent -1 of 84 bytes
| [***** short pause here *****]
| XMT: Forming Confirm, 920 ms elapsed.
| XMT:  X-- IA_NA 3e:28:e6:37
| XMT:  | X-- Confirm Address fd42:198e:d2a5:1d10:1e4c:ac80:7f2e:f59e
| XMT:  V IA_NA appended.
| XMT: Confirm on eth0, interval 1910ms.
| send_packet6: Cannot assign requested address
| dhc6: sendpacket6() sent -1 of 84 bytes
| [***** short pause here *****]
| XMT: Forming Confirm, 2830 ms elapsed.
| XMT:  X-- IA_NA 3e:28:e6:37
| XMT:  | X-- Confirm Address fd42:198e:d2a5:1d10:1e4c:ac80:7f2e:f59e
| XMT:  V IA_NA appended.
| XMT: Confirm on eth0, interval 3710ms.
| RCV: Reply message on eth0 from fe80::3896:5cff:fe61:baf0.
| RCV:  X-- Server ID: 00:01:00:01:1f:c5:e1:fb:b8:ae:ed:75:5f:9a
| message status code Success: "all addresses still on link"
| PRC: Bound to lease 00:01:00:01:1f:c5:e1:fb:b8:ae:ed:75:5f:9a.


After the fix you see:
| # dhclient -6 -1 -v $dev
| Internet Systems Consortium DHCP Client 4.1-ESV-R4
| Copyright 2004-2011 Internet Systems Consortium.
| All rights reserved.
| For info, please visit https://www.isc.org/software/dhcp/
| 
| Bound to *:546
| Listening on Socket/eth0
| Sending on   Socket/eth0
| PRC: Confirming active lease (INIT-REBOOT).
| 
| XMT: Forming Confirm, 0 ms elapsed.
| XMT:  X-- IA_NA 3e:28:e6:37
| XMT:  | X-- Confirm Address fd42:198e:d2a5:1d10:1e4c:ac80:7f2e:f59e
| XMT:  V IA_NA appended.
| XMT: Confirm on eth0, interval 920ms.
| send_packet6: Cannot assign requested address
| dhc6: sendpacket6() sent -1 of 84 bytes

So I'm marking this fixed on precise and trusty also as we fix the error messages like:
  send_packet6: Cannot assign requested address
  dhc6: sendpacket6() sent -1 of 84 bytes



** Tags added: verification-done-precise verification-done-trusty

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https://bugs.launchpad.net/bugs/1633479

Title:
  dhclient does not wait for ipv6 dad (duplicate address detection)

Status in isc-dhcp package in Ubuntu:
  Fix Released
Status in isc-dhcp source package in Precise:
  Fix Committed
Status in isc-dhcp source package in Trusty:
  Fix Committed
Status in isc-dhcp source package in Xenial:
  Fix Released
Status in isc-dhcp source package in Yakkety:
  Fix Committed

Bug description:
  dhclient -6 does not wait for an interface go through duplicate address detection.
  As a result the following will almost always fail:

   $ dev=eth0
   $ ip link set down dev $dev
   $ dhclient -6 -1 -v eth0
   Internet Systems Consortium DHCP Client 4.3.3
   Copyright 2004-2015 Internet Systems Consortium.
   All rights reserved.
   For info, please visit https://www.isc.org/software/dhcp/

   Can't bind to dhcp address: Cannot assign requested address
   Please make sure there is no other dhcp server
   running and that there's no entry for dhcp or
   bootp in /etc/inetd.conf.   Also make sure you
   are not running HP JetAdmin software, which
   includes a bootp server.

   If you think you have received this message due to a bug rather
   than a configuration issue please read the section on submitting
   bugs on either our web page at www.isc.org or in the README file
   before submitting a bug.  These pages explain the proper
   process and the information we find helpful for debugging..
   $ echo $?
   1

  Related bugs:
   * bug 1447715: dhclient -6: Can't bind to dhcp address: Cannot assign requested address
   * bug 1633562: 'dhclient -6 -S' does not bring interface up 

  ProblemType: Bug
  DistroRelease: Ubuntu 16.10
  Package: isc-dhcp-client 4.3.3-5ubuntu15
  ProcVersionSignature: Ubuntu 4.8.0-22.24-generic 4.8.0
  Uname: Linux 4.8.0-22-generic x86_64
  NonfreeKernelModules: zfs zunicode zcommon znvpair zavl
  ApportVersion: 2.20.3-0ubuntu8
  Architecture: amd64
  CurrentDesktop: Unity
  Date: Fri Oct 14 09:18:52 2016
  EcryptfsInUse: Yes
  InstallationDate: Installed on 2015-07-23 (449 days ago)
  InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Alpha amd64 (20150722.1)
  SourcePackage: isc-dhcp
  UpgradeStatus: No upgrade log present (probably fresh install)

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