--- /dev/null
+=============================
+Netlink interface for ethtool
+=============================
+
+
+Basic information
+=================
+
+Netlink interface for ethtool uses generic netlink family ``ethtool``
+(userspace application should use macros ``ETHTOOL_GENL_NAME`` and
+``ETHTOOL_GENL_VERSION`` defined in ``<linux/ethtool_netlink.h>`` uapi
+header). This family does not use a specific header, all information in
+requests and replies is passed using netlink attributes.
+
+The ethtool netlink interface uses extended ACK for error and warning
+reporting, userspace application developers are encouraged to make these
+messages available to user in a suitable way.
+
+Requests can be divided into three categories: "get" (retrieving information),
+"set" (setting parameters) and "action" (invoking an action).
+
+All "set" and "action" type requests require admin privileges
+(``CAP_NET_ADMIN`` in the namespace). Most "get" type requests are allowed for
+anyone but there are exceptions (where the response contains sensitive
+information). In some cases, the request as such is allowed for anyone but
+unprivileged users have attributes with sensitive information (e.g.
+wake-on-lan password) omitted.
+
+
+Conventions
+===========
+
+Attributes which represent a boolean value usually use NLA_U8 type so that we
+can distinguish three states: "on", "off" and "not present" (meaning the
+information is not available in "get" requests or value is not to be changed
+in "set" requests). For these attributes, the "true" value should be passed as
+number 1 but any non-zero value should be understood as "true" by recipient.
+In the tables below, "bool" denotes NLA_U8 attributes interpreted in this way.
+
+In the message structure descriptions below, if an attribute name is suffixed
+with "+", parent nest can contain multiple attributes of the same type. This
+implements an array of entries.
+
+
+Request header
+==============
+
+Each request or reply message contains a nested attribute with common header.
+Structure of this header is
+
+ ============================== ====== =============================
+ ``ETHTOOL_A_HEADER_DEV_INDEX`` u32 device ifindex
+ ``ETHTOOL_A_HEADER_DEV_NAME`` string device name
+ ``ETHTOOL_A_HEADER_FLAGS`` u32 flags common for all requests
+ ============================== ====== =============================
+
+``ETHTOOL_A_HEADER_DEV_INDEX`` and ``ETHTOOL_A_HEADER_DEV_NAME`` identify the
+device message relates to. One of them is sufficient in requests, if both are
+used, they must identify the same device. Some requests, e.g. global string
+sets, do not require device identification. Most ``GET`` requests also allow
+dump requests without device identification to query the same information for
+all devices providing it (each device in a separate message).
+
+``ETHTOOL_A_HEADER_FLAGS`` is a bitmap of request flags common for all request
+types. The interpretation of these flags is the same for all request types but
+the flags may not apply to requests. Recognized flags are:
+
+ ================================= ===================================
+ ``ETHTOOL_FLAG_COMPACT_BITSETS`` use compact format bitsets in reply
+ ``ETHTOOL_FLAG_OMIT_REPLY`` omit optional reply (_SET and _ACT)
+ ================================= ===================================
+
+New request flags should follow the general idea that if the flag is not set,
+the behaviour is backward compatible, i.e. requests from old clients not aware
+of the flag should be interpreted the way the client expects. A client must
+not set flags it does not understand.
+
+
+List of message types
+=====================
+
+All constants identifying message types use ``ETHTOOL_CMD_`` prefix and suffix
+according to message purpose:
+
+ ============== ======================================
+ ``_GET`` userspace request to retrieve data
+ ``_SET`` userspace request to set data
+ ``_ACT`` userspace request to perform an action
+ ``_GET_REPLY`` kernel reply to a ``GET`` request
+ ``_SET_REPLY`` kernel reply to a ``SET`` request
+ ``_ACT_REPLY`` kernel reply to an ``ACT`` request
+ ``_NTF`` kernel notification
+ ============== ======================================
+
+``GET`` requests are sent by userspace applications to retrieve device
+information. They usually do not contain any message specific attributes.
+Kernel replies with corresponding "GET_REPLY" message. For most types, ``GET``
+request with ``NLM_F_DUMP`` and no device identification can be used to query
+the information for all devices supporting the request.
+
+If the data can be also modified, corresponding ``SET`` message with the same
+layout as corresponding ``GET_REPLY`` is used to request changes. Only
+attributes where a change is requested are included in such request (also, not
+all attributes may be changed). Replies to most ``SET`` request consist only
+of error code and extack; if kernel provides additional data, it is sent in
+the form of corresponding ``SET_REPLY`` message which can be suppressed by
+setting ``ETHTOOL_FLAG_OMIT_REPLY`` flag in request header.
+
+Data modification also triggers sending a ``NTF`` message with a notification.
+These usually bear only a subset of attributes which was affected by the
+change. The same notification is issued if the data is modified using other
+means (mostly ioctl ethtool interface). Unlike notifications from ethtool
+netlink code which are only sent if something actually changed, notifications
+triggered by ioctl interface may be sent even if the request did not actually
+change any data.
+
+``ACT`` messages request kernel (driver) to perform a specific action. If some
+information is reported by kernel (which can be suppressed by setting
+``ETHTOOL_FLAG_OMIT_REPLY`` flag in request header), the reply takes form of
+an ``ACT_REPLY`` message. Performing an action also triggers a notification
+(``NTF`` message).
+
+Later sections describe the format and semantics of these messages.
+
+
+Request translation
+===================
+
+The following table maps ioctl commands to netlink commands providing their
+functionality. Entries with "n/a" in right column are commands which do not
+have their netlink replacement yet.
+
+ =================================== =====================================
+ ioctl command netlink command
+ =================================== =====================================
+ ``ETHTOOL_GSET`` n/a
+ ``ETHTOOL_SSET`` n/a
+ ``ETHTOOL_GDRVINFO`` n/a
+ ``ETHTOOL_GREGS`` n/a
+ ``ETHTOOL_GWOL`` n/a
+ ``ETHTOOL_SWOL`` n/a
+ ``ETHTOOL_GMSGLVL`` n/a
+ ``ETHTOOL_SMSGLVL`` n/a
+ ``ETHTOOL_NWAY_RST`` n/a
+ ``ETHTOOL_GLINK`` n/a
+ ``ETHTOOL_GEEPROM`` n/a
+ ``ETHTOOL_SEEPROM`` n/a
+ ``ETHTOOL_GCOALESCE`` n/a
+ ``ETHTOOL_SCOALESCE`` n/a
+ ``ETHTOOL_GRINGPARAM`` n/a
+ ``ETHTOOL_SRINGPARAM`` n/a
+ ``ETHTOOL_GPAUSEPARAM`` n/a
+ ``ETHTOOL_SPAUSEPARAM`` n/a
+ ``ETHTOOL_GRXCSUM`` n/a
+ ``ETHTOOL_SRXCSUM`` n/a
+ ``ETHTOOL_GTXCSUM`` n/a
+ ``ETHTOOL_STXCSUM`` n/a
+ ``ETHTOOL_GSG`` n/a
+ ``ETHTOOL_SSG`` n/a
+ ``ETHTOOL_TEST`` n/a
+ ``ETHTOOL_GSTRINGS`` n/a
+ ``ETHTOOL_PHYS_ID`` n/a
+ ``ETHTOOL_GSTATS`` n/a
+ ``ETHTOOL_GTSO`` n/a
+ ``ETHTOOL_STSO`` n/a
+ ``ETHTOOL_GPERMADDR`` rtnetlink ``RTM_GETLINK``
+ ``ETHTOOL_GUFO`` n/a
+ ``ETHTOOL_SUFO`` n/a
+ ``ETHTOOL_GGSO`` n/a
+ ``ETHTOOL_SGSO`` n/a
+ ``ETHTOOL_GFLAGS`` n/a
+ ``ETHTOOL_SFLAGS`` n/a
+ ``ETHTOOL_GPFLAGS`` n/a
+ ``ETHTOOL_SPFLAGS`` n/a
+ ``ETHTOOL_GRXFH`` n/a
+ ``ETHTOOL_SRXFH`` n/a
+ ``ETHTOOL_GGRO`` n/a
+ ``ETHTOOL_SGRO`` n/a
+ ``ETHTOOL_GRXRINGS`` n/a
+ ``ETHTOOL_GRXCLSRLCNT`` n/a
+ ``ETHTOOL_GRXCLSRULE`` n/a
+ ``ETHTOOL_GRXCLSRLALL`` n/a
+ ``ETHTOOL_SRXCLSRLDEL`` n/a
+ ``ETHTOOL_SRXCLSRLINS`` n/a
+ ``ETHTOOL_FLASHDEV`` n/a
+ ``ETHTOOL_RESET`` n/a
+ ``ETHTOOL_SRXNTUPLE`` n/a
+ ``ETHTOOL_GRXNTUPLE`` n/a
+ ``ETHTOOL_GSSET_INFO`` n/a
+ ``ETHTOOL_GRXFHINDIR`` n/a
+ ``ETHTOOL_SRXFHINDIR`` n/a
+ ``ETHTOOL_GFEATURES`` n/a
+ ``ETHTOOL_SFEATURES`` n/a
+ ``ETHTOOL_GCHANNELS`` n/a
+ ``ETHTOOL_SCHANNELS`` n/a
+ ``ETHTOOL_SET_DUMP`` n/a
+ ``ETHTOOL_GET_DUMP_FLAG`` n/a
+ ``ETHTOOL_GET_DUMP_DATA`` n/a
+ ``ETHTOOL_GET_TS_INFO`` n/a
+ ``ETHTOOL_GMODULEINFO`` n/a
+ ``ETHTOOL_GMODULEEEPROM`` n/a
+ ``ETHTOOL_GEEE`` n/a
+ ``ETHTOOL_SEEE`` n/a
+ ``ETHTOOL_GRSSH`` n/a
+ ``ETHTOOL_SRSSH`` n/a
+ ``ETHTOOL_GTUNABLE`` n/a
+ ``ETHTOOL_STUNABLE`` n/a
+ ``ETHTOOL_GPHYSTATS`` n/a
+ ``ETHTOOL_PERQUEUE`` n/a
+ ``ETHTOOL_GLINKSETTINGS`` n/a
+ ``ETHTOOL_SLINKSETTINGS`` n/a
+ ``ETHTOOL_PHY_GTUNABLE`` n/a
+ ``ETHTOOL_PHY_STUNABLE`` n/a
+ ``ETHTOOL_GFECPARAM`` n/a
+ ``ETHTOOL_SFECPARAM`` n/a
+ =================================== =====================================
projects / platform / kernel / linux-rpi.git / commitdiff