The .rst documentation contains a brief description of the user interface and includes kernel-doc generated from uapi header.
Signed-off-by: Leonard Crestez cdleonard@gmail.com --- Documentation/networking/index.rst | 1 + Documentation/networking/tcp_authopt.rst | 51 ++++++++++++++++++++++++ 2 files changed, 52 insertions(+) create mode 100644 Documentation/networking/tcp_authopt.rst
diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index bacadd09e570..b134037c94ec 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -102,10 +102,11 @@ 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..72adb7a891ce --- /dev/null +++ b/Documentation/networking/tcp_authopt.rst @@ -0,0 +1,51 @@ +.. 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 through an 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 global for each network +namespace, this means that all sockets for which TCP_AUTHOPT is enabled will +be affected by the same set of keys. + +Manipulating keys requires ``CAP_NET_ADMIN``. + +Key binding +----------- + +Keys can be bound to remote addresses in a way that is somewhat similar to +``TCP_MD5SIG``. By default a key matches all connections but matching criteria can +be specified as fields inside struct tcp_authopt_key together with matching +flags in tcp_authopt_key.flags. The sort of these "matching criteria" can +expand over time by increasing the size of `struct tcp_authopt_key` and adding +new flags. + + * Address binding is optional, by default keys match all addresses + * Local address is ignored, matching is done by remote address + * Ports are ignored + +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