[openssl-dev] AF_ALG engine support and kernel versions
noloader at gmail.com
Fri Mar 25 09:08:51 UTC 2016
> Looking at the code in engines/afalg/e_afalg.c, there is the following:
> #define K_MAJ 4
> #define K_MIN1 1
> #define K_MIN2 0
> #if LINUX_VERSION_CODE <= KERNEL_VERSION(K_MAJ, K_MIN1, K_MIN2)
> # warning "AFALG ENGINE requires Kernel Headers >= 4.1.0"
> # warning "Skipping Compilation of AFALG engine"
> It appears AF_ALG was added to the kernel at 2.6.38. Asynchronous I/O
> support appears to have surfaced in the kernel at 2.5.23.
> Where is the requirement for 4.1 coming from?
> Also, "Fixing asynchronous I/O, again", dated January 2016
> (http://lwn.net/Articles/671649/) could explain why later 4.x kernels
> are having problems with the afalgtest.
I think this has to do with the asynchronous cipher support. Its just
a guess because I can't seem to find any information on it. CHANGES
talks about "ASYNC support" between 1.0.2 and 1.1.1, but it does not
Its not clear to me were the supporting kernel versions begin or end.
It appears asynchronous cipher stuff is still being cut-in. This
meesage is from two weeks ago: "[PATCH v3] crypto: af_alg - add async
support to algif_aead",
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