fine when a lot of different flows to be ciphered/deciphered are involved.
However, when a software crypto driver is used, there are
situations where we could benefit from making crypto(9) multi threaded:
- a single flow is to be ciphered: only one thread is used to cipher it,
- a single ESP flow is to be deciphered: only one thread is used to
decipher it.
The idea here is to call crypto(9) using a new mode (CRYPTO_F_ASYNC) to
dispatch the crypto jobs on multiple threads, if the underlying crypto
driver is working in synchronous mode.
Another flag is added (CRYPTO_F_ASYNC_KEEPORDER) to make crypto(9)
dispatch the crypto jobs in the order they are received (an additional
queue/thread is used), so that the packets are reinjected in the network
using the same order they were posted.
A new sysctl net.inet.ipsec.async_crypto can be used to activate
this new behavior (disabled by default).
Submitted by: Emeric Poupon <emeric.poupon@stormshield.eu>
Reviewed by: ae, jmg, jhb
Differential Revision: https://reviews.freebsd.org/D10680
Sponsored by: Stormshield
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