Merge branch 'TLS-offload-rx-netdev-and-mlx5'
Boris Pismenny says: ==================== TLS offload rx, netdev & mlx5 The following series provides TLS RX inline crypto offload. v5->v4: - Remove the Kconfig to mutually exclude both IPsec and TLS v4->v3: - Remove the iov revert for zero copy send flow v2->v3: - Fix typo - Adjust cover letter - Fix bug in zero copy flows - Use network byte order for the record number in resync - Adjust the sequence provided in resync v1->v2: - Fix bisectability problems due to variable name changes - Fix potential uninitialized return value This series completes the generic infrastructure to offload TLS crypto to a network devices. It enables the kernel TLS socket to skip decryption and authentication operations for SKBs marked as decrypted on the receive side of the data path. Leaving those computationally expensive operations to the NIC. This infrastructure doesn't require a TCP offload engine. Instead, the NIC decrypts a packet's payload if the packet contains the expected TCP sequence number. The TLS record authentication tag remains unmodified regardless of decryption. If the packet is decrypted successfully and it contains an authentication tag, then the authentication check has passed. Otherwise, if the authentication fails, then the packet is provided unmodified and the KTLS layer is responsible for handling it. Out-Of-Order TCP packets are provided unmodified. As a result, in the slow path some of the SKBs are decrypted while others remain as ciphertext. The GRO and TCP layers must not coalesce decrypted and non-decrypted SKBs. At the worst case a received TLS record consists of both plaintext and ciphertext packets. These partially decrypted records must be reencrypted, only to be decrypted. The notable differences between SW KTLS and NIC offloaded TLS implementations are as follows: 1. Partial decryption - Software must handle the case of a TLS record that was only partially decrypted by HW. This can happen due to packet reordering. 2. Resynchronization - tls_read_size calls the device driver to resynchronize HW whenever it lost track of the TLS record framing in the TCP stream. The infrastructure should be extendable to support various NIC offload implementations. However it is currently written with the implementation below in mind: The NIC identifies packets that should be offloaded according to the 5-tuple and the TCP sequence number. If these match and the packet is decrypted and authenticated successfully, then a syndrome is provided to software. Otherwise, the packet is unmodified. Decrypted and non-decrypted packets aren't coalesced by the network stack, and the KTLS layer decrypts and authenticates partially decrypted records. The NIC provides an indication whenever a resync is required. The resync operation is triggered by the KTLS layer while parsing TLS record headers. Finally, we measure the performance obtained by running single stream iperf with two Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz machines connected back-to-back with Innova TLS (40Gbps) NICs. We compare TCP (upper bound) and KTLS-Offload running both in Tx and Rx. The results show that the performance of offload is comparable to TCP. | Bandwidth (Gbps) | CPU Tx (%) | CPU rx (%) TCP | 28.8 | 5 | 12 KTLS-Offload-Tx-Rx | 28.6 | 7 | 14 Paper: https://netdevconf.org/2.2/papers/pismenny-tlscrypto-talk.pdf ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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