[Click] Linux integration diagram?

[Beyers Cronje]

Adam,

FromDevice will not work. However, you should be able to accomplish this
through FromHost/ToHost elements. See
http://read.cs.ucla.edu/click/elements/fromhost and
http://read.cs.ucla.edu/click/elements/tohost

Alternative you could also use userlevel Click to accomplish this through
the userlevel KernelTun or FromHost/ToHost elements. See
http://read.cs.ucla.edu/click/elements/kerneltun ,
http://read.cs.ucla.edu/click/elements/fromhost.u and
http://read.cs.ucla.edu/click/elements/tohost.u

Beyers

On 7/23/07, Adam M <click at irotas.net> wrote:
>
> Hi Beyers,
>
> That explanation actually helped a lot! I didn't really understand
> exactly how PollDevice and FromDevice operated and how they were
> distinct, so thanks for the explanation.
>
> To give you a little more detail, basically what I'm trying to figure
> out is if there's any inherent reason why FromDevice would not work with
> a "virtual" interface created using TUN on Linux. We use a virtual
> interface to simulate such things as radio networks, and we're
> considering using Click as the routing framework.
>
> I'm not just convinced yet that the two can play nicely together. I'm
> don't know if you will either (it seems that not many people understand
> virtual interfaces that well), but I figured I'd take a shot. :)
>
> Thanks again,
> Adam
>
>
> On Mon, 23 Jul 2007 18:44:17 +0200, "Beyers Cronje" <bcronje at gmail.com>
> said:
> > Hi Adam,
> >
> > I haven't seen a diagram as such. I can try and give you a simple
> > overview
> > of how it works (on the receive side of things). Click kernel module
> > ethernet integration works on two methods depending on whether you use
> > PollDevice or FromDevice.
> >
> > PollDevice - You can only use PollDevice if you have an Intel e1000 NIC
> > with
> > the Click polling patch applied. This polling patch modifies the e1000
> > driver and in short does the following, it disables interrupts on the
> NIC
> > which in turn means that Linux will not process any packets from the
> NIC.
> > Then Click through PollDevice continually polls the receive queue of the
> > NIC
> > and receives any packets on the NIC's rx queue. It also supplies the
> > driver
> > with clean SKBs after it has received packets. Once the packet is inside
> > Click it follows the push/pull processing of Click.
> >
> > FromDevice - FromDevice works with any Linux NIC driver. The Click
> kernel
> > patch modifies the Linux netif_receive_skb() function to intercept
> > packets
> > before Linux process them. This means interrupts are still in play. See
> > netif_receive_skb() in the kernel patch along with FromDevice element
> > code.
> >
> > See https://pdos.csail.mit.edu/pipermail/click/2005-April/003845.htmlfor
> > an
> > overview on how Click's push/pull packet processing operates.
> >
> > Hope this helps a bit.
> >
> > Beyers
>