[openib-general] Re: RMPP Message Format Errors

[Eitan Zahavi]

Hal Rosenstock wrote:
>  
> The number of records is an SA thing and not RMPP thing. This is
> transparent to RMPP itself.
The transparency to the RMPP is an RMPP implementation choice.
Having incorrect paylen in the first segment is a compliancy violation. 
It should be either 0 or correct value.
>  
> The need to determine the number of records is a consumer issue (SA or
> SA client). To do this, AttributeOffset and (at least the last)
> PayloadLength field is needed (as one can't rely on the first
> PayloadLength being non zero).
True. But how would the SA or SA Client that gets an assembled MAD be 
able to tell the number of records?
Also, does the current implementation let the client do the assembly?
If so how would it handle abort transactions?

If the re-assembly is done by the MAD service then the client only gets 
offset in the MAD header and probably mad size which is MAD Header + 
RMPP header + SA extra header + data.

Anyway, the last segment paylen was incorrect too.
>  
> -- Hal
> 
> ________________________________
> 
> From: Eitan Zahavi [mailto:eitan at mellanox.co.il]
> Sent: Mon 8/22/2005 1:54 AM
> To: 'Sean Hefty'; Eitan Zahavi; Hal Rosenstock
> Cc: OPENIB GENERAL; Liran Sorani; Amit Krig; Aviram Gutman
> Subject: RE: RMPP Message Format Errors
> 
> 
> Hi Sean,
>  
> You wrote:
> "Note that the current implementation of the RMPP code ignores the
> payload length on the receive side, and instead relies on the last bit
> to determine the end of a transfer."
>  
> But the receive side needs to calculate back the correct size of the
> assembled MAD.
> If it is done in kernel or user it does not matter. To my best knowledge
> the only way to calculate how many records are enclosed in an RMPP
> message is to use the paylen and offset.
> How can it be done without looking at paylen ?
>  
> EZ
>  
> Eitan Zahavi
> Design Technology Director
> Mellanox Technologies LTD
> Tel:+972-4-9097208
> Fax:+972-4-9593245
> P.O. Box 586 Yokneam 20692 ISRAEL
>  
> -----Original Message-----
> From: Sean Hefty [mailto:sean.hefty at intel.com] 
> Sent: Monday, August 22, 2005 1:01 AM
> To: 'Eitan Zahavi'; Hal Rosenstock
> Cc: OPENIB GENERAL; Liran Sorani; Amit Krig; Aviram Gutman
> Subject: RE: RMPP Message Format Errors
>  
> Please let me know if you will have time to dig into these problems or
> if I should try and resolve them myself and provide patches. 
> I will not be able to look at this until early next week (with IDF
> running this week), but I will try to do so.   So, it wouldn't surprise
> me if the receive side accepted an invalid RMPP MAD.
> - Sean