[PATCH 02/19] docs: Add user documentation for tcp_authopt
From: Leonard Crestez <hidden>
Date: 2021-09-21 16:19:51
Also in:
linux-crypto, linux-kselftest, lkml
Subsystem:
documentation, networking [general], the rest · Maintainers:
Jonathan Corbet, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The .rst documentation contains a brief description of the user interface and includes kernel-doc generated from uapi header. Signed-off-by: Leonard Crestez <redacted> --- Documentation/networking/index.rst | 1 + Documentation/networking/tcp_authopt.rst | 44 ++++++++++++++++++++++++ 2 files changed, 45 insertions(+) create mode 100644 Documentation/networking/tcp_authopt.rst
diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst
index 58bc8cd367c6..f5c324a060d8 100644
--- a/Documentation/networking/index.rst
+++ b/Documentation/networking/index.rst@@ -100,10 +100,11 @@ Contents: strparser switchdev sysfs-tagging tc-actions-env-rules tcp-thin + tcp_authopt team timestamping tipc tproxy tuntap
diff --git a/Documentation/networking/tcp_authopt.rst b/Documentation/networking/tcp_authopt.rst
new file mode 100644
index 000000000000..484f66f41ad5
--- /dev/null
+++ b/Documentation/networking/tcp_authopt.rst@@ -0,0 +1,44 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +TCP Authentication Option +========================= + +The TCP Authentication option specified by RFC5925 replaces the TCP MD5 +Signature option. It similar in goals but not compatible in either wire formats +or ABI. + +Interface +========= + +Individual keys can be added to or removed from a TCP socket by using +TCP_AUTHOPT_KEY setsockopt and a ``struct tcp_authopt_key``. There is no +support for reading back keys and updates always replace the old key. These +structures represent "Master Key Tuples (MKTs)" as described by the RFC. + +Per-socket options can set or read using the TCP_AUTHOPT sockopt and a ``struct +tcp_authopt``. This is optional: doing setsockopt TCP_AUTHOPT_KEY is +sufficient to enable the feature. + +Configuration associated with TCP Authentication is indepedently attached to +each TCP socket. After listen and accept the newly returned socket gets an +independent copy of relevant settings from the listen socket. + +Key binding +----------- + +Keys can be bound to remote addresses in a way that is similar to TCP_MD5. + + * The full address must match (/32 or /128) + * Ports are ignored + * Address binding is optional, by default keys match all addresses + +RFC5925 requires that key ids do not overlap when tcp identifiers (addr/port) +overlap. This is not enforced by linux, configuring ambiguous keys will result +in packet drops and lost connections. + +ABI Reference +============= + +.. kernel-doc:: include/uapi/linux/tcp.h + :identifiers: tcp_authopt tcp_authopt_flag tcp_authopt_key tcp_authopt_key_flag tcp_authopt_alg
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2.25.1