dhcp client is broken on interfaces with checksum offloading (eg Xen vif)

[Michal Suchanek]

Checksum on such interfaces is invalid so it is an error to drop packets with invalid checksum coming from such interfaces.

See links

https://qa.mandriva.com/show_bug.cgi?id=63320

https://bugs.mageia.org/show_bug.cgi?id=1243

http://pkgs.fedoraproject.org/gitweb/?p=dhcp.git;a=blob_plain;f=dhcp-4.2.2-xen-checksum.patch;hb=HEAD

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: isc-dhcp-client 4.1.1-P1-17ubuntu10
ProcVersionSignature: Error: [Errno 2] No such file or directory: '/proc/version_signature'
Uname: Linux 3.1.0-1-amd64 x86_64
NonfreeKernelModules: ext3 jbd mbcache xen_netfront xen_blkfront
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Tue Dec 20 12:38:13 2011
DhclientLeases:

InstallationMedia: Ubuntu-Server 11.10 "Oneiric Ocelot" - Release amd64 (20111011)
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: isc-dhcp
UpgradeStatus: No upgrade log present (probably fresh install)