Hi,

On Mon, Mar 08, 2010 at 09:00:14AM -0700, James Yonan wrote:
> >I have not yet figured out that part.  I did my debugging with Wireshark
> >("see what packets move back and forth and stare at the packet details").
> 
> While Windows doesn't support "printf" in device drivers, the TAP driver 
> defines the DEBUGP macro that tries to do the same thing.

I've seen these, but was missing the next steps - "how do I get to read
these messages".

[..]
> Next, there are two possible ways to view the debugging output:
> 
> Get the WinDBG tool from MS.  All of the DEBUGP calls will output log 
> info in a form that can be received by WinDBG.

Will check that.  There are "some debuggers" as part of the WDK, but I
have not yet looked into these in more detail.

> Use a special feature of OpenVPN on Windows that allows it to get the 
> DEBUGP messages directly from the TAP driver and output them along with 
> the normal OpenVPN log output.  This feature is enabled at --verb level 
> 6 and is internally referred to as D_TAP_WIN32_DEBUG in errlevel.h.

Now THAT is seriously cool :-)

I have seen that the code writes the debug messages "to a buffer", but
couldn't find out (yet) how to access the debug messages.

Thanks a lot for this.  I will use this information to improve the debug
printing of IPv6 packets (which is non-existant yet) and also add a bit
of debug printing to the code that does neighbor discovery / neighbor
advertisement spoofing, so it's visible in the logs what happens and
why.

gert
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Gert Doering - Munich, Germany                             g...@greenie.muc.de
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