supplemental data handshake message

[Carolin Latze]

Hi Simon,

I finally got it running!! :-)

The _gnutls_buffer_init was the problem that fixed the length issue. The 
next problem was that I did not expect to get the data only in 
_gnutls_helloworld_supp_recv. Instead I tried to parse it again (reading 
the length etc) which caused segfaults. After I figured out that I do 
not have to parse anything anymore, I got it running :-)

I will prepare some (short) documentation that I will post to the list 
in the next few days. Feel free to copy it into your documentation in 
order to make it easier for other people when they try to implement a 
new supplemental data handshake message.

Regards and thanks a lot for your help!
Carolin

On 05/05/2010 02:51 PM, Simon Josefsson wrote:
> Carolin Latze<carolin.latze at unifr.ch>  writes:
>
>    
>> Hi Simon,
>>
>>
>>      
>>> It is difficult to tell from just description of the problem...  Try
>>> printing the entire buffer that is sent by _gnutls_gen_supplement and
>>> the buffer received by _gnutls_parse_supplemental and hand-check that
>>> they are correct and match.
>>>        
>> If I did not do something completely wrong (which is ofc always
>> possible), they do not match, which is weird. Like you will see in the
>> source code below, I printed buf at the end of
>> _gnutls_gen_supplemental as well as data at the beginning of
>> _gnutls_parse_supplemental.
>>      
> There is a bug in your printing code, it has to be:
>
> _gnutls_debug_log ("EXT[%p]: supp send buffer: ",session);
> for(i=0;i<buf->length;i++) _gnutls_debug_log ("%02x",buf->data[i]&  0xFF);
>
> Check the warnings when you build the code, it would catch issues like
> that.
>
> With that, the buffers sent and received are identical:
>
> |<2>| EXT[0x9073780]: supp send buffer: |<2>| 00|<2>| 00|<2>| 07|<2>| 00|<2>| 01|<2>| 00|<2>| 03|<2>| 6c|<2>| 6c|<2>| 6f|<2>|
>
> |<2>| EXT[0x8de9c58]: recv supp buf: |<2>| 00|<2>| 00|<2>| 07|<2>| 00|<2>| 01|<2>| 00|<2>| 03|<2>| 6c|<2>| 6c|<2>| 6f|<2>|
>
> Another bug was that your ext_helloworld.c cleared out the buffer, you
> need to remove this call:
>
> 	_gnutls_buffer_init(buf);
>
>    
>>> Maybe you could push a git branch with your
>>> work somewhere, so we can more easily reproduce the problem?
>>>
>>>
>>>        
>> Due to the lack of a git server, I put my GnuTLS version on a webserver:
>> http://diuf.unifr.ch/people/latzec/gnutls-2.9.11-CL.tar.gz
>>
>> If you prefer a git branch, I need to get a server first :-) (which is
>> probably not impossible, but needs more time :))
>>      
> A tarball is fine.  You can push to free git servers out there, such as
> repo.or.cz.
>
> /Simon
>