IPsec RFC6479 support for replay window sizes up to 2^32 - 32 packets.
Since the previous algorithm, based on bit shifting, does not scale
with large replay windows, the algorithm used here is based on
RFC 6479: IPsec Anti-Replay Algorithm without Bit Shifting.
The replay window will be fast to be updated, but will cost as many bits
in RAM as its size.
The previous implementation did not provide a lock on the replay window,
which may lead to replay issues.
Reviewed by: ae
Obtained from: email@example.com
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D8468