Re: communicating from the user space

Am Sonntag, 22. Februar 2015, 22:26:32 schrieb Nikos Mavrogiannopoulos:

Hi Nikos,

On Sun, 2015-02-22 at 16:04 +0100, Stephan Mueller wrote:

quoted

Am Sonntag, 22. Februar 2015, 18:32:34 schrieb sri sowj:

Hi sri,

quoted

Hi Stephen,

It was a great information with respective PF_ALG , I have explored a
bit on openssl and algorithms prospect , Please let me know if
anything to add to it.

openssl crypto engine:

below are the steps to enable openssl to communicate using pf/af_alg.

#1:git clone http://src.carnivore.it/users/common/af_alg/

Yes, that is it. But it is not fully efficient as it does not use vmsplice
where appropriate. So, libkcapi should be faster in several use cases.

When would vmsplice be appropriate? As far as I understand vmsplice adds
a cost on operations for small data, which is the majority of use cases
in crypto. In the measurements I did for cryptodev-linux [0] vmsplice
did improve performance only for more than 64k packets which is never
the case with real world crypto (TLS has a maximum of 14k for example).

According to my measurements, I have the following heuristic for symmetric 
ciphers: if the ciphertext is less than 1<<13, then use one sendmsg call. 
Otherwise use vmsplice.

For AEAD, my library uses 3 IOVecs which means that sendmsg is faster in any 
case (the overhead for setting up 3 IOVecs in kernel space for vmsplice is 
higher than sendmsg copy).

For hashes, I yet have to make the measurements.

regards,
Nikos

[0]. http://cryptodev-linux.org/comparison.html


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Ciao
Stephan