[PATCH 0/2] librte_net: add crc computation support

[Jasvinder Singh <jasvinder.singh@intel.com>]

In some applications, CRC (Cyclic Redundancy Check) needs to be computed or
updated during packet processing operations. This patchset adds software
implementation of some common standard CRCs (32-bit Ethernet CRC as per
Ethernet/[ISO/IEC 8802-3] and 16-bit CCITT-CRC [ITU-T X.25]). Two
versions of each 32-bit and 16-bit CRC calculation are proposed.

The first version presents a fast and efficient CRC generation on IA
processors by using the carry-less multiplication instruction – PCLMULQDQ
(i.e SSE4.2 instrinsics). In this implementation, a parallelized folding
approach has been used to first reduce an arbitrary length buffer to a small
fixed size length buffer (16 bytes) with the help of precomputed constants.
The resultant single 16-bytes chunk is further reduced by Barrett reduction
method to generate final CRC value. For more details on the implementation,
see reference [1].

The second version presents the fallback solution to support the CRC
generation without needing any specific support from CPU (for examples-
SSE4.2 intrinsics). It is based on generic Look-Up Table(LUT) algorithm that
uses precomputed 256 element table as explained in reference[2].

Following APIs have been added;

(i) rte_net_crc_init()   
(ii)rte_net_crc_calc()

The first API (i) initalises the data structures required for CRC computation
and this api should be used only once in the application before using second
API (ii) for 16-bit and 32-bit CRC calculations.

References:
[1] Fast CRC Computation for Generic Polynomials Using PCLMULQDQ Instruction
http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
[2] A PAINLESS GUIDE TO CRC ERROR DETECTION ALGORITHMS
http://www.ross.net/crc/download/crc_v3.txt

Jasvinder Singh (2):
  librte_net: add crc init and compute APIs
  app/test: add unit test for CRC computation

 app/test/Makefile                  |   2 +
 app/test/test_crc.c                | 229 +++++++++++++
 lib/librte_net/Makefile            |   2 +
 lib/librte_net/rte_net_crc.c       | 657 +++++++++++++++++++++++++++++++++++++
 lib/librte_net/rte_net_crc.h       | 101 ++++++
 lib/librte_net/rte_net_version.map |   8 +
 6 files changed, 999 insertions(+)
 create mode 100644 app/test/test_crc.c
 create mode 100644 lib/librte_net/rte_net_crc.c
 create mode 100644 lib/librte_net/rte_net_crc.h

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2.5.5