[v6,0/6] ipsec: add inbound SAD

According to RFC 4301 IPSec implementation needs an inbound SA database (SAD).
For each incoming inbound IPSec-protected packet (ESP or AH) it has to
perform a lookup within it’s SAD.
Lookup should be performed by:
Security Parameters Index (SPI) + destination IP (DIP) + source IP (SIP)
  or SPI + DIP
  or SPI only
and an implementation has to return the “longest” existing match.
These series extend DPDK IPsec library with SAD table implementation that:
- conforms to the RFC requirements above
- can scale up to millions of entries
- supports fast lookups
- supports incremental updates

Initial series provide an API to create/destroy SAD, and to
add/delete/lookup entries within given SAD table.
Under the hood it uses three librte_hash tables each of which contains
an entries for a specific SA type (either it is addressed by SPI only
or SPI+DIP or SPI+DIP+SIP) Also this patch series introduce test-sad
application to measure performance of the library. According to our
measurements on SKX for 1M entries average lookup cost is ~80 cycles,
average add cost ~500 cycles.

v6:
- fix rte_ipsec_sad_lookup() comments regarding return value
- added parallel lookup feature to test-sad app
- added read/write concurrency support flag to test-sad app
- added programmer's guide
- updated release notes

v5:
- small fix in rte_ipsec_sad_create()
- add comments in rte_ipsec_sad.h

v4:
- fixes in test-sad app
- small fixes in rte_ipsec_sad_create()
- fixes in test_find_existing() from unittests

v3:
- fixes in rte_ipsec_sad_create() and rte_ipsec_sad_find_existing()
- fix typos
- updated commit messages
- added test_find_existing() in unittests

v2:
- various bugs fixed
- rte_ipsec_sad_free renamed to rte_ipsec_sad_destroy
- added const qualifier to rte_ipsec_sad_key *key for add/delete
- added more comments into the code
- added ipv6 support into the testsad app
- added <DEL> measurement into the testsad app
- random SPI values are generated without dups
- added support for configurable burst size in testsad app
- added verbose mode into the testsad app

Vladimir Medvedkin (6):
  ipsec: add inbound SAD API
  ipsec: add SAD create/destroy implementation
  ipsec: add SAD add/delete/lookup implementation
  test/ipsec: add ipsec SAD autotests
  app: add test-sad application
  doc/ipsec: update ipsec programmer's guide

 app/Makefile                           |   1 +
 app/meson.build                        |   3 +-
 app/test-sad/Makefile                  |  18 +
 app/test-sad/main.c                    | 668 +++++++++++++++++++++++++
 app/test-sad/meson.build               |   6 +
 app/test/Makefile                      |   1 +
 app/test/autotest_data.py              |   6 +
 app/test/meson.build                   |   1 +
 app/test/test_ipsec_sad.c              | 887 +++++++++++++++++++++++++++++++++
 doc/guides/prog_guide/ipsec_lib.rst    | 152 ++++++
 doc/guides/rel_notes/release_19_11.rst |   3 +
 lib/librte_ipsec/Makefile              |   4 +-
 lib/librte_ipsec/ipsec_sad.c           | 515 +++++++++++++++++++
 lib/librte_ipsec/meson.build           |   6 +-
 lib/librte_ipsec/rte_ipsec_sad.h       | 176 +++++++
 lib/librte_ipsec/rte_ipsec_version.map |   7 +
 16 files changed, 2449 insertions(+), 5 deletions(-)
 create mode 100644 app/test-sad/Makefile
 create mode 100644 app/test-sad/main.c
 create mode 100644 app/test-sad/meson.build
 create mode 100644 app/test/test_ipsec_sad.c
 create mode 100644 lib/librte_ipsec/ipsec_sad.c
 create mode 100644 lib/librte_ipsec/rte_ipsec_sad.h