[Click] Quick newbie questions

[Kurtis Heimerl]

On 10/17/07, Beyers Cronje <bcronje at gmail.com> wrote:
>
> Hi Kurtis
>
> I'm running in user-level as my application is only a proof of concept,
> > and
> > I've been unable to get insmod to load the kernel module correctly.
>
>
> You should always use 'click-install' to install the click kernel module
> and not insmod/modprobe. Follow the INSTALL file and you will get the kernel
> module working.
>


I'm using click-install as per the install file, but  it's not working. I'm
guessing it's that my kernel is a gentoo distro one. It compiled without
error, but the module loading is kicking out. With this as my intuition, I
could get a plain kernel and try it out, but since you say there's little
difference, it's probably not worth my time.

Is there a default configuration for a simple IP router? There is a perl
> > script which generates an IP click config file, but it's seemingly for
> > kernel mode only. I suppose I could modify it, but what i'm looking for
> > now
> > is a known working case to help me understand what's going on. I can't
> > seem
> > to find a default config for user space IP routing.
>
>
> From the 'make-ip-conf.pl' file:
> "
> # Make a Click IP router configuration.  This script generates a
> # configuration using PollDevices. You can change it to use
> # FromDevices; see the comment above the $ifs array, below.  The
> # output is intended for the Linux kernel module; however, by making
> # the change from PollDevices to FromDevices, and setting $local_host
> # appropriately, the configuration will also work at userlevel.
> "
>
> So all you need to do to get a working userlevel config is to change the
> second column of the $ifs array to 0 and set the $local_host to something
> like "Print(toh) -> Discard", and whoalla you have a working userlevel IP
> router config. Obviously you have to also edit the $ifs array entries to
> suit your router.
>


Ah! Thanks! I noticed the "no poll devices" error message when trying to use
this script, so I switched those. I should have read the file more in depth.


Secondly, what are my losses for running in user mode? I had assumed the
> > main loss would be efficiency, but some elements seem to require kernel
> > mode. Is this set in stone, or simply the default behavior?
>
>
> Your main loss will be performance and NOT functionality. Also SMP click
> is only supported in the kernel module.
>
> I would say MOST features are available across both userlevel Click and
> kernel module Click.
> There are some kernel only and userlevel only elements that provide the
> same "feature" in both modes i.e. there's a kernel FromDevice element as
> well as a userlevel FromDevice element.
> Then obviously there are some elements that will only be available in
> userlevel, typically elements that require floating point operation or file
> access that is not supported in the kernel ie FromDump, and some only
> available in kernel module i.e. PollDevice that require kernel level
> access to devices etc.
>
> If you have a look at http://read.cs.ucla.edu/click/elements you'll see
> that the vast majority of features is provided across both modes.
>


Nice, so the "drivers" column is the level it can be used at. This will help
me a lot. Thanks.

Hope this helps.
>


It did, thanks a ton!

Beyers Cronje
>
>