Mostly this is a thin shim around existing code to integrate with enc_xform
and cryptosoft (+ cryptodev).
Expand the cryptodev buffer used to match that of Chacha20's native block
size as a performance enhancement for chacha20_xform_crypt_multi.
xforms that support processing of multiple blocks at a time (to support more
efficient modes, for example) can define the encrypt_ and decrypt_multi
interfaces. If these interfaces are not present, the generic cryptosoft
code falls back on the block-at-a-time encrypt/decrypt interfaces.
Stream ciphers may support arbitrarily sized inputs (equivalent to an input
block size of 1 byte) but may be more efficient if a larger block is passed.
Sponsored by: Dell EMC Isilon
Keep xform.c as a meta-file including the broken out bits
existing code that includes xform.c continues to work as normal
Individual algorithms can now be reused elsewhere, including outside
of the kernel
Reviewed by: bapt (previous version), gnn, delphij
Approved by: secteam
MFC after: 1 week
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D4674
