[Tfug] WRT54G (et al.) hacking

[Bexley Hall]

Hi, Eric,

--- On Wed, 6/10/09, Eric Gearhart <eric at nixwizard.net> wrote:

> > Is anyone *intimately* familiar with the hardware on
> > these beasts?  My understanding is that they appear
> > (to the software) as three network interfaces:
> > - the WLAN interface
> > - the wireless interface
> > - the "switch" interface
> >
> > The latter is where I am looking for details.
> > Specifically, is this *just* a switch glued onto
> > a regular network interface (i.e., the third
> > interface on the CPU looks like a "regular"
> > interface FEEDING a 5 port switch)?  Or, is
> > there some extra magic involved?
> >
> > Ideally, I would like to treat (in software)
> > the four external "ports" (discounting the WLAN)
> > as SEPARATE interfaces (i.e., disable the "switch"
> > functionality)
> 
> I'm somewhat intimately familiar... I love the non-castrated WRT54G
> line. Each port appears as its own separate port afaik, and they are
> bridged together using standard Linux bridging (br0 or br1 I think...
> don't have my WRT nearby at the moment).

Hmmm... so far, what I have seen of the hardware suggests this
is NOT the case.  I.e., there *is* a real "switch" in the box.
So, most of the traffic *between* those 4 ports is handled without
the processor even knowing about it.

There are some controls that the processor can exercise over the
functionality of that switch.  I haven't yet figured out if I
could "trick" it into behaving like I want (probably by disabling
the mechanism by which the switch "learns" the addresses of the
various nodes on each port).

> OpenWRT could do what you're trying to do I believe... heck
> even dd-wrt has options for the bridging and VLANs of the
> individual ports I believe.

I'm not sure that's the same thing.  I want the box to look
like it has eth[1-4] for those four "ports" plus eth0 for the
WAN connection (ignoring the WLAN for the moment).

I want software to implement the switch functionality
(as I don't intend to use it that way!)

> Also - if you want one that has the specs of the original
> WRT 54Gs
> Linksys was gracious enough to offer a WRT54GL (note the
> L). From the
> wikipedia article
> (http://en.wikipedia.org/wiki/Linksys_WRT54G_series#WRT54GL):
> 
> "Linksys released the WRT54GL in 2005 to support
> third-party firmware
> based on Linux, after the original WRT54G line was switched
> from Linux
> to VxWorks, starting with version 5. The WRT54GL is
> technically a
> reissue of the version 4 WRT54G. Cisco was sued by the FSF
> for copyright infringement, but the case was settled"

Yes.  But the oldest (v1.0) hardware is the most extensible.
Starting at 1.1, Linksys made the design considerably more
"constrained" (though some older models have more horsepower)

--don