Overview
========
A kernel TLS Tx only socket option for TCP sockets.
Similarly to the kernel TLS socket(https://lwn.net/Articles/665602),
only symmetric crypto is done in the kernel, as well as TLS record framing.
The handshake remains in userspace, and the negotiated cipher keys/iv are
provided to the TCP socket.
Today, userspace TLS must perform 2 passes over the data. First, it has to
encrypt the data. Second, the data is copied to the TCP socket in the kernel.
Kernel TLS avoids one pass over the data by encrypting the data from userspace
pages into kernelspace buffers.
Non application-data TLS records must be encrypted using the latest crypto
state available in the kernel. It is possible to get the crypto context from
the kernel and encrypt such recrods in user-space. But we choose to encrypt
such TLS records in the kernel by setting the MSG_OOB flag and providing the
record type with the data.
TLS Tx crypto offload is a new feature of network devices. It enables the
kernel TLS socket to skip encryption and authentication operations on the
transmit side of the data path, delegating those to the NIC. In turn, the NIC
encrypts packets that belong to an offloaded TLS socket on the fly. The NIC
does not modify any packet headers. It expects to receive fully framed TCP
packets with TLS records as payload. The NIC replaces plaintext with ciphertext
and fills the authentication tag. The NIC does not hold any state beyond the
context needed to encrypt the next expected packet, i.e. expected TCP sequence
number and crypto state.
There are 2 flows for TLS Tx offload, a fast path and a slow path.
Fast path: packet matches the expected TCP sequence number in the context.
Slow path: packet does not match the expected TCP sequence number in the
context. For example: TCP retransmissions. For a packet in the slow path, we
need to resynchronize the crypto context of the NIC by providing the TLS record
data for that packet before it could be encrypted and transmitted by the NIC.
Motivation
==========
1) Performance: The CPU overhead of encryption in the data path is high, at
least 4x for netperf over TLS between 2 machines connected back-to-back.
Our single stream performance tests show that using crypto offload for TLS
sockets achieves the same throughput as plain TCP traffic while increasing CPU
utilization by only
x1.4.
2) Flexibility: The protocol stack is implemented entirely on the host CPU.
Compared to solutions based on TCP offload, this approach offloads only
encryption. Keeping memory management, congestion control, etc. in the host CPU.
Notes
=====
1) New paths:
o net/tls - TLS layer in kernel
o drivers/net/ethernet/mellanox/accelerator/* - NIC driver support,
currently implemented as seperated modules.
In the future this code will go into the mlx5 driver. We attached to this
patch only the module that integrated with TLS layer.
The complete NIC sample driver is available at
https://github.com/Mellanox/tls-offload/tree/tx_rfc_v5
2) We implemented support for this API in OpenSSL 1.1.0, the code is available
at https://github.com/Mellanox/tls-openssl/tree/master
3) TLS crypto offload was presented during netdevconf1.2, more details could be
found in the presentation and paper:
https://netdevconf.org/1.2/session.html?boris-pismenny
4) These RFC patches are based on kernel 4.9-rc7.
Aviad Yehezkel (5):
tcp: export do_tcp_sendpages function
tcp: export tcp_rate_check_app_limited function
tcp: Add TLS socket options for TCP sockets
tls: tls offload support
mlx/tls: Enable MLX5_CORE_QP_SIM mode for tls
Dave Watson (2):
crypto: Add gcm template for rfc5288
crypto: rfc5288 aesni optimized intel routines
Ilya Lesokhin (8):
tcp: Add clean acked data hook
net: Add TLS offload netdevice and socket support
mlx/mlx5_core: Allow sending multiple packets
mlx/tls: Hardware interface
mlx/tls: Sysfs configuration interface Configure the driver/hardware
interface via sysfs.
mlx/tls: Add mlx_accel offload driver for TLS
mlx/tls: TLS offload driver Add the main module entrypoints and tie
the module into the build system
net/tls: Add software offload
MAINTAINERS | 14 +
arch/x86/crypto/aesni-intel_asm.S | 6 +
arch/x86/crypto/aesni-intel_avx-x86_64.S | 4 +
arch/x86/crypto/aesni-intel_glue.c | 105 ++-
crypto/gcm.c | 122 ++++
crypto/tcrypt.c | 14 +-
crypto/testmgr.c | 16 +
crypto/testmgr.h | 47 ++
drivers/net/ethernet/mellanox/Kconfig | 1 +
drivers/net/ethernet/mellanox/Makefile | 1 +
.../net/ethernet/mellanox/accelerator/tls/Kconfig | 11 +
.../net/ethernet/mellanox/accelerator/tls/Makefile | 4 +
.../net/ethernet/mellanox/accelerator/tls/tls.c | 658 +++++++++++++++++++
.../net/ethernet/mellanox/accelerator/tls/tls.h | 100 +++
.../ethernet/mellanox/accelerator/tls/tls_cmds.h | 112 ++++
.../net/ethernet/mellanox/accelerator/tls/tls_hw.c | 429 ++++++++++++
.../net/ethernet/mellanox/accelerator/tls/tls_hw.h | 49 ++
.../ethernet/mellanox/accelerator/tls/tls_main.c | 77 +++
.../ethernet/mellanox/accelerator/tls/tls_sysfs.c | 196 ++++++
.../ethernet/mellanox/accelerator/tls/tls_sysfs.h | 47 ++
drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 11 +-
include/linux/netdevice.h | 23 +
include/net/inet_connection_sock.h | 2 +
include/net/tcp.h | 2 +
include/net/tls.h | 228 +++++++
include/uapi/linux/Kbuild | 1 +
include/uapi/linux/tcp.h | 2 +
include/uapi/linux/tls.h | 84 +++
net/Kconfig | 1 +
net/Makefile | 1 +
net/ipv4/tcp.c | 37 +-
net/ipv4/tcp_input.c | 3 +
net/ipv4/tcp_rate.c | 1 +
net/tls/Kconfig | 12 +
net/tls/Makefile | 7 +
net/tls/tls_device.c | 594 +++++++++++++++++
net/tls/tls_main.c | 352 ++++++++++
net/tls/tls_sw.c | 729 +++++++++++++++++++++
38 files changed, 4078 insertions(+), 25 deletions(-)
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/Kconfig
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/Makefile
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/tls.c
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/tls.h
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/tls_cmds.h
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/tls_hw.c
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/tls_hw.h
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/tls_main.c
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/tls_sysfs.c
create mode 100644 drivers/net/ethernet/mellanox/accelerator/tls/tls_sysfs.h
create mode 100644 include/net/tls.h
create mode 100644 include/uapi/linux/tls.h
create mode 100644 net/tls/Kconfig
create mode 100644 net/tls/Makefile
create mode 100644 net/tls/tls_device.c
create mode 100644 net/tls/tls_main.c
create mode 100644 net/tls/tls_sw.c
--
2.7.4
