Lines Matching +full:packet +full:- +full:based
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
25 on a packet by packet basis, provided the packets arrive in order.
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 --
48 for crypto offload based on the socket the packet is attached to,
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 --
121 --
142 to be possible, the device has to keep a small amount of segment-to-segment
155 --
162 once the packet reaches the device.
164 a connection identifier (note that a 5-tuple lookup is insufficient to identify
166 and hands them to the device. The device identifies the packet as requiring
172 --
174 Before a packet is DMAed to the host (but after NIC's embedded switching
175 and packet transformation functions) the device validates the Layer 4
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
179 is always TCP). If the packet is matched to a connection, the device confirms
181 (record delineation, decryption, authentication for each record in the packet).
184 per-packet context (descriptor) passed to the host.
186 Upon reception of a TLS offloaded packet, the driver sets
189 and non-decrypted segments do not get coalesced (e.g. by GRO or socket layer)
195 In presence of packet drops or network packet reordering, the device may lose
206 --
209 in similar ways to the receive side-retransmissions - local drops
219 segment has to be passed to the device as part of the packet context,
223 the actual packet.
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
280 the next record starts inside 3, based on record length in segment 1.
294 .. kernel-figure:: tls-offload-reorder-bad.svg
314 (based on the length fields at guessed locations).
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
358 --
369 in the packet being dropped. For example if a packet got out of order
371 be encrypted such packet must be dropped.
374 --
377 side it should pass the packet to the host's networking stack as it was
381 result in passing the unmodified packet to the software fallback. This means
383 decryption is not advised. In other words either all records in the packet
384 had been handled successfully and authenticated or the packet has to be passed
385 to the host's stack as it was on the wire (recovering original packet in the
388 The Linux networking stack does not provide a way of reporting per-packet
392 A packet should also not be handled by the TLS offload if it contains
409 --------------------
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
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
465 * ``tx_tls_drop_bypass_req`` - number of TX packets which were part of a TLS
474 5-tuple matching limitations
475 ----------------------------
477 The device can only recognize received packets based on the 5-tuple
480 or virtual networking. However, many packet transformations performed
482 any intermediate software device, therefore a 5-tuple match may
488 ------------
495 ---------------
497 A device is permitted to perform packet reordering for consecutive
502 -----------------------------------------------------
509 ----------------------------
512 packet headers.
514 The device should not depend on any packet headers beyond what is strictly
518 -------------
526 -------------------
538 Similarly, device-offloaded TLS decryption implies doing RXCSUM. If the user