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Boris Pismenny says: ==================== TLS offload, netdev & MLX5 support The following series provides TLS TX inline crypto offload. v1->v2: - Added IS_ENABLED(CONFIG_TLS_DEVICE) and a STATIC_KEY for icsk_clean_acked - File license fix - Fix spelling, comment by DaveW - Move memory allocations out of tls_set_device_offload and other misc fixes, comments by Kiril. v2->v3: - Reversed xmas tree where needed and style fixes - Removed the need for skb_page_frag_refill, per Eric's comment - IPv6 dependency fixes v3->v4: - Remove "inline" from functions in C files - Make clean_acked_data_enabled a static variable and add enable/disable functions to control it. - Remove unnecessary variable initialization mentioned by ShannonN - Rebase over TLS RX - Refactor the tls_software_fallback to reduce the number of variables mentioned by KirilT v4->v5: - Add missing CONFIG_TLS_DEVICE v5->v6: - Move changes to the software implementation into a seperate patch - Fix some checkpatch warnings - GPL export the enable/disable clean_acked_data functions v6->v7: - Use the dst_entry to obtain the netdev in dev_get_by_index - Remove the IPv6 patch since it is redundent now v7->v8: - Fix a merge conflict in mlx5 header v8->v9: - Fix false -Wmaybe-uninitialized warning - Fix empty space in the end of new files v9->v10: - Remove default "n" in net/Kconfig This series adds a generic infrastructure to offload TLS crypto to a network devices. It enables the kernel TLS socket to skip encryption and authentication operations on the transmit side of the data path. Leaving those computationally expensive operations to the NIC. The NIC offload infrastructure builds TLS records and pushes them to the TCP layer just like the SW KTLS implementation and using the same API. TCP segmentation is mostly unaffected. Currently the only exception is that we prevent mixed SKBs where only part of the payload requires offload. In the future we are likely to add a similar restriction following a change cipher spec record. The notable differences between SW KTLS and NIC offloaded TLS implementations are as follows: 1. The offloaded implementation builds "plaintext TLS record", those records contain plaintext instead of ciphertext and place holder bytes instead of authentication tags. 2. The offloaded implementation maintains a mapping from TCP sequence number to TLS records. Thus given a TCP SKB sent from a NIC offloaded TLS socket, we can use the tls NIC offload infrastructure to obtain enough context to encrypt the payload of the SKB. A TLS record is released when the last byte of the record is ack'ed, this is done through the new icsk_clean_acked callback. The infrastructure should be extendable to support various NIC offload implementations. However it is currently written with the implementation below in mind: The NIC assumes that packets from each offloaded stream are sent as plaintext and in-order. It keeps track of the TLS records in the TCP stream. When a packet marked for offload is transmitted, the NIC encrypts the payload in-place and puts authentication tags in the relevant place holders. The responsibility for handling out-of-order packets (i.e. TCP retransmission, qdisc drops) falls on the netdev driver. The netdev driver keeps track of the expected TCP SN from the NIC's perspective. If the next packet to transmit matches the expected TCP SN, the driver advances the expected TCP SN, and transmits the packet with TLS offload indication. If the next packet to transmit does not match the expected TCP SN. The driver calls the TLS layer to obtain the TLS record that includes the TCP of the packet for transmission. Using this TLS record, the driver posts a work entry on the transmit queue to reconstruct the NIC TLS state required for the offload of the out-of-order packet. It updates the expected TCP SN accordingly and transmit the now in-order packet. The same queue is used for packet transmission and TLS context reconstruction to avoid the need for flushing the transmit queue before issuing the context reconstruction request. Expected TCP SN is accessed without a lock, under the assumption that TCP doesn't transmit SKBs from different TX queue concurrently. If packets are rerouted to a different netdevice, then a software fallback routine handles encryption. Paper: https://www.netdevconf.org/1.2/papers/netdevconf-TLS.pdf ==================== Signed-off-by: David S. Miller <davem@davemloft.net> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.