From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCHv2] vhost-net: add dhclient work-around from userspace Date: Mon, 28 Jun 2010 18:30:28 +0300 Message-ID: <20100628153028.GA1452@redhat.com> References: <20100628100807.GA30685@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: kvm@vger.kernel.org, virtualization@lists.osdl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ykaul@redhat.com, markmc@redhat.com Return-path: Content-Disposition: inline In-Reply-To: <20100628100807.GA30685@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, Jun 28, 2010 at 01:08:07PM +0300, Michael S. Tsirkin wrote: > Userspace virtio server has the following hack > so guests rely on it, and we have to replicate it, too: > > Use port number to detect incoming IPv4 DHCP response packets, > and fill in the checksum for these. > > The issue we are solving is that on linux guests, some apps > that use recvmsg with AF_PACKET sockets, don't know how to > handle CHECKSUM_PARTIAL; > The interface to return the relevant information was added > in 8dc4194474159660d7f37c495e3fc3f10d0db8cc, > and older userspace does not use it. > One important user of recvmsg with AF_PACKET is dhclient, > so we add a work-around just for DHCP. > > Don't bother applying the hack to IPv6 as userspace virtio does not > have a work-around for that - let's hope guests will do the right > thing wrt IPv6. > > Signed-off-by: Michael S. Tsirkin Tested-by: Laine Stump