this will look like TLS records had been tampered with and will result
in record authentication failures.
+TLS_RX_EXPECT_NO_PAD
+~~~~~~~~~~~~~~~~~~~~
+
+TLS 1.3 only. Expect the sender to not pad records. This allows the data
+to be decrypted directly into user space buffers with TLS 1.3.
+
+This optimization is safe to enable only if the remote end is trusted,
+otherwise it is an attack vector to doubling the TLS processing cost.
+
+If the record decrypted turns out to had been padded or is not a data
+record it will be decrypted again into a kernel buffer without zero copy.
+Such events are counted in the ``TlsDecryptRetry`` statistic.
+
Statistics
==========
- ``TlsDeviceRxResync`` -
number of RX resyncs sent to NICs handling cryptography
+
+- ``TlsDecryptRetry`` -
+ number of RX records which had to be re-decrypted due to
+ ``TLS_RX_EXPECT_NO_PAD`` mis-prediction. Note that this counter will
+ also increment for non-data records.
+
+- ``TlsRxNoPadViolation`` -
+ number of data RX records which had to be re-decrypted due to
+ ``TLS_RX_EXPECT_NO_PAD`` mis-prediction.