Am 11.07.2010 12:47, schrieb Michael S. Tsirkin: > On Fri, Jul 09, 2010 at 05:17:36PM +0200, Patrick McHardy wrote: >> Am 09.07.2010 00:29, schrieb Michael S. Tsirkin: >>> This adds a `CHECKSUM' target, which can be used in the iptables mangle >>> table. >>> >>> You can use this target to compute and fill in the checksum in >>> an IP packet that lacks a checksum. This is particularly useful, >>> if you need to work around old applications such as dhcp clients, >>> that do not work well with checksum offloads, but don't want to >>> disable checksum offload in your device. >>> >>> The problem happens in the field with virtualized applications. >>> For reference, see Red Hat bz 605555, as well as >>> http://www.spinics.net/lists/kvm/msg37660.html >>> >>> Typical expected use (helps old dhclient binary running in a VM): >>> iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM >>> --checksum-fill >> >> I'm not sure this is something we want to merge upstream and >> support indefinitely. Dave suggested this as a temporary >> out-of-tree workaround until the majority of guest dhcp clients >> are fixed. Has anything changed that makes this course of >> action impractical? > > If I understand what Dave said correctly, it's up to you ... > > The arguments for putting this upstream are: > > Given the track record, I wouldn't hope for quick fix in the majority of > guest dhcp clients, unfortunately :(. We are talking years here. > Even after that, one of the uses of virtualization is > to keep old guests running. So yes, I think we'll > keep using work-arounds for this for a very long time. > > Further, since we have to add the module and we have to teach management > to program it, it will be much less painful for everyone > involved if we can put the code upstream, rather than forking > management code. Fair enough, its simple enough that I don't expect much maintenance overhead. -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
