Merge PR #26875 into nautilus

* refs/pull/26875/head:
	common: implement HMACs on top of OpenSSL.
	msg/async, v2: switch the pre-auth mechanism to HMAC-SHA256.
	include/types: beef sha_digest_t up with encode and compare.
	auth: add hmac_sha256() to CryptoKey.
	msg/async, v2: introduce pre_auth exchanges with CRC32.
	msg/async, v2: introduce pre_auth buffers.
	msg/async, v2: rectify the encapsulation of rx_segments_{desc,data}.
	msg/async, v2: rework decoding of MessageFrame.
	msg/async, v2: limit the num_segments to non-empty segments.
	msg/async, v2: drop the bl onwire space optimization in ControlFrames.
	msg/async, v2: clean up ret handling in ProtocolV2::write().
	msg/async, v2: drop next_payload_len as we don't need anymore.
	msg/async, v2: drop temp_buffer and limitations driven by it.
	msg/async, v2: switch to rx_buffer_t entirely.
	msg/async, v2: rx continuations use buffer::ptr_node.
	msg/async, v2: use bptr continuation for segment reading.
	msg/async: introduce bptr-carrying continuations.
	msg/async: replace CONTINUATION_PARAM() with specialized types.
	msg/async, v2: ::_banner_exchange() takes CtRef instead of CtPtr.
	msg/async: avoid extra pointers in continuation definitions.
	msg/async, v2: dissect setting stream handlers into ::finish_auth().
	msg/async, v2: drop ceph_msg_header2 handling from ControlFrames.
	msg/async, v2: drop the SignedEncryptedFrame entirely.
	msg/async, v2: reintroduce segment aligment. It's compile-time now.
	msg/async, v2: generalize Frame about number of segments.
	msg/async, v2: rework and generalize Frame encryption.
	msg/async, v2: rework the class hierarchy - introduce MessageFrame.
	msg/async, v2: rework the class hierarchy - introduce ControlFrame.
	msg/async/ProtocolV2: remove obsolete AuthFlags

Reviewed-by: Sage Weil <sage@redhat.com>