Lines Matching +full:stream +full:- +full:mode +full:- +full:support
1 .. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
13 For details regarding the user-facing interface refer to the TLS
18 * Software crypto mode (``TLS_SW``) - CPU handles the cryptography.
24 * Packet-based NIC offload mode (``TLS_HW``) - the NIC handles crypto
26 This mode integrates best with the kernel stack and is described in detail
28 (``ethtool`` flags ``tls-hw-tx-offload`` and ``tls-hw-rx-offload``).
29 * Full TCP NIC offload mode (``TLS_HW_RECORD``) - mode of operation where
33 abilities or QoS and packet scheduling (``ethtool`` flag ``tls-hw-record``).
35 The operation mode is selected automatically based on device configuration,
36 offload opt-in or opt-out on per-connection basis is not currently supported.
39 --
43 mode) and then hands the modified scatter list to the TCP layer. From this
46 In ``TLS_HW`` mode the encryption is not performed in the TLS ULP.
52 --
63 .. kernel-figure:: tls-offload-layers.svg
82 network device is offload-capable and attempts the offload. In case offload
89 .. code-block:: c
98 to retrieve the connection 5-tuple and socket family (IPv4 vs IPv6).
108 --
111 of the stream will start exactly at the ``start_offload_tcp_sn`` sequence
121 --
142 to be possible, the device has to keep a small amount of segment-to-segment
155 --
164 a connection identifier (note that a 5-tuple lookup is insufficient to identify
172 --
176 checksum and performs a 5-tuple lookup to find any TLS connection the packet
177 may belong to (technically a 4-tuple
178 lookup is sufficient - IP addresses and TCP port numbers, as the protocol
184 per-packet context (descriptor) passed to the host.
189 and non-decrypted segments do not get coalesced (e.g. by GRO or socket layer)
196 synchronization with the TLS stream, and require a resync with the kernel's
200 added to the device table and are in TLS_HW mode. For example,
206 --
209 in similar ways to the receive side-retransmissions - local drops
225 In this mode depending on the implementation the driver can either ask
228 with the previous stream state - assuming that the out of order segment
245 .. code-block:: c
253 .. code-block:: c
263 --
269 .. kernel-figure:: tls-offload-reorder-good.svg
270 :alt: reorder of non-header segment
273 Reorder of non-header segment
294 .. kernel-figure:: tls-offload-reorder-bad.svg
303 the device will lose synchronization with the stream.
305 Stream scan resynchronization
308 When the device gets out of sync and the stream reaches TCP sequence
323 and counting all records since the just-confirmed one, it adds the number
331 restart scan. Given how unlikely falsely-matching stream is, however,
335 asynchronously to the packet stream and record may get processed
338 Stack-driven resynchronization
343 If the connection is configured in this mode the stack automatically
358 --
374 --
388 The Linux networking stack does not provide a way of reporting per-packet
409 --------------------
411 The number of connections device can support can be exposed via
415 -------------------------------
420 significant performance impact on non-offloaded streams.
425 Following minimum set of TLS-related statistics should be reported
428 * ``rx_tls_decrypted_packets`` - number of successfully decrypted RX packets
429 which were part of a TLS stream.
430 * ``rx_tls_decrypted_bytes`` - number of TLS payload bytes in RX packets
432 * ``rx_tls_ctx`` - number of TLS RX HW offload contexts added to device for
434 * ``rx_tls_del`` - number of TLS RX HW offload contexts deleted from device
436 * ``rx_tls_resync_req_pkt`` - number of received TLS packets with a resync
438 * ``rx_tls_resync_req_start`` - number of times the TLS async resync request
440 * ``rx_tls_resync_req_end`` - number of times the TLS async resync request
441 properly ended with providing the HW tracked tcp-seq.
442 * ``rx_tls_resync_req_skip`` - number of times the TLS async resync request
444 * ``rx_tls_resync_res_ok`` - number of times the TLS resync response call to
446 * ``rx_tls_resync_res_skip`` - number of times the TLS resync response call to
448 * ``rx_tls_err`` - number of RX packets which were part of a TLS stream
450 * ``tx_tls_encrypted_packets`` - number of TX packets passed to the device
452 * ``tx_tls_encrypted_bytes`` - number of TLS payload bytes in TX packets
454 * ``tx_tls_ctx`` - number of TLS TX HW offload contexts added to device for
456 * ``tx_tls_ooo`` - number of TX packets which were part of a TLS stream
458 * ``tx_tls_skip_no_sync_data`` - number of TX packets which were part of
459 a TLS stream and arrived out-of-order, but skipped the HW offload routine
462 * ``tx_tls_drop_no_sync_data`` - number of TX packets which were part of
463 a TLS stream dropped, because they arrived out of order and associated
465 * ``tx_tls_drop_bypass_req`` - number of TX packets which were part of a TLS
466 stream dropped, because they contain both data that has been encrypted by
474 5-tuple matching limitations
475 ----------------------------
477 The device can only recognize received packets based on the 5-tuple
482 any intermediate software device, therefore a 5-tuple match may
488 ------------
495 ---------------
502 -----------------------------------------------------
504 Offloaded ``ktls`` sockets should support standard TCP stack features
509 ----------------------------
518 -------------
526 -------------------
538 Similarly, device-offloaded TLS decryption implies doing RXCSUM. If the user