ethtool: provide string sets with STRSET_GET request

Requests a contents of one or more string sets, i.e. indexed arrays of
strings; this information is provided by ETHTOOL_GSSET_INFO and
ETHTOOL_GSTRINGS commands of ioctl interface. Unlike ioctl interface, all
information can be retrieved with one request and mulitple string sets can
be requested at once.

There are three types of requests:

  - no NLM_F_DUMP, no device: get "global" stringsets
  - no NLM_F_DUMP, with device: get string sets related to the device
  - NLM_F_DUMP, no device: get device related string sets for all devices

Client can request either all string sets of given type (global or device
related) or only specific sets. With ETHTOOL_A_STRSET_COUNTS flag set, only
set sizes (numbers of strings) are returned.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 73 insertions, 2 deletions

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 7797f1237472..3912cb0eb9c6 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -176,6 +176,18 @@ according to message purpose:
   ``_NTF``          kernel notification
   ==============    ======================================
 
+Userspace to kernel:
+
+  ===================================== ================================
+  ``ETHTOOL_MSG_STRSET_GET``            get string set
+  ===================================== ================================
+
+Kernel to userspace:
+
+  ===================================== ================================
+  ``ETHTOOL_MSG_STRSET_GET_REPLY``      string set contents
+  ===================================== ================================
+
 ``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``
@@ -207,6 +219,65 @@ an ``ACT_REPLY`` message. Performing an action also triggers a notification
 Later sections describe the format and semantics of these messages.
 
 
+STRSET_GET
+==========
+
+Requests contents of a string set as provided by ioctl commands
+``ETHTOOL_GSSET_INFO`` and ``ETHTOOL_GSTRINGS.`` String sets are not user
+writeable so that the corresponding ``STRSET_SET`` message is only used in
+kernel replies. There are two types of string sets: global (independent of
+a device, e.g. device feature names) and device specific (e.g. device private
+flags).
+
+Request contents:
+
+ +---------------------------------------+--------+------------------------+
+ | ``ETHTOOL_A_STRSET_HEADER``           | nested | request header         |
+ +---------------------------------------+--------+------------------------+
+ | ``ETHTOOL_A_STRSET_STRINGSETS``       | nested | string set to request  |
+ +-+-------------------------------------+--------+------------------------+
+ | | ``ETHTOOL_A_STRINGSETS_STRINGSET+`` | nested | one string set         |
+ +-+-+-----------------------------------+--------+------------------------+
+ | | | ``ETHTOOL_A_STRINGSET_ID``        | u32    | set id                 |
+ +-+-+-----------------------------------+--------+------------------------+
+
+Kernel response contents:
+
+ +---------------------------------------+--------+-----------------------+
+ | ``ETHTOOL_A_STRSET_HEADER``           | nested | reply header          |
+ +---------------------------------------+--------+-----------------------+
+ | ``ETHTOOL_A_STRSET_STRINGSETS``       | nested | array of string sets  |
+ +-+-------------------------------------+--------+-----------------------+
+ | | ``ETHTOOL_A_STRINGSETS_STRINGSET+`` | nested | one string set        |
+ +-+-+-----------------------------------+--------+-----------------------+
+ | | | ``ETHTOOL_A_STRINGSET_ID``        | u32    | set id                |
+ +-+-+-----------------------------------+--------+-----------------------+
+ | | | ``ETHTOOL_A_STRINGSET_COUNT``     | u32    | number of strings     |
+ +-+-+-----------------------------------+--------+-----------------------+
+ | | | ``ETHTOOL_A_STRINGSET_STRINGS``   | nested | array of strings      |
+ +-+-+-+---------------------------------+--------+-----------------------+
+ | | | | ``ETHTOOL_A_STRINGS_STRING+``   | nested | one string            |
+ +-+-+-+-+-------------------------------+--------+-----------------------+
+ | | | | | ``ETHTOOL_A_STRING_INDEX``    | u32    | string index          |
+ +-+-+-+-+-------------------------------+--------+-----------------------+
+ | | | | | ``ETHTOOL_A_STRING_VALUE``    | string | string value          |
+ +-+-+-+-+-------------------------------+--------+-----------------------+
+ | ``ETHTOOL_A_STRSET_COUNTS_ONLY``      | flag   | return only counts    |
+ +---------------------------------------+--------+-----------------------+
+
+Device identification in request header is optional. Depending on its presence
+a and ``NLM_F_DUMP`` flag, there are three type of ``STRSET_GET`` requests:
+
+ - no ``NLM_F_DUMP,`` no device: get "global" stringsets
+ - no ``NLM_F_DUMP``, with device: get string sets related to the device
+ - ``NLM_F_DUMP``, no device: get device related string sets for all devices
+
+If there is no ``ETHTOOL_A_STRSET_STRINGSETS`` array, all string sets of
+requested type are returned, otherwise only those specified in the request.
+Flag ``ETHTOOL_A_STRSET_COUNTS_ONLY`` tells kernel to only return string
+counts of the sets, not the actual strings.
+
+
 Request translation
 ===================
 
@@ -242,7 +313,7 @@ have their netlink replacement yet.
   ``ETHTOOL_GSG``                     n/a
   ``ETHTOOL_SSG``                     n/a
   ``ETHTOOL_TEST``                    n/a
-  ``ETHTOOL_GSTRINGS``                n/a
+  ``ETHTOOL_GSTRINGS``                ``ETHTOOL_MSG_STRSET_GET``
   ``ETHTOOL_PHYS_ID``                 n/a
   ``ETHTOOL_GSTATS``                  n/a
   ``ETHTOOL_GTSO``                    n/a
@@ -270,7 +341,7 @@ have their netlink replacement yet.
   ``ETHTOOL_RESET``                   n/a
   ``ETHTOOL_SRXNTUPLE``               n/a
   ``ETHTOOL_GRXNTUPLE``               n/a
-  ``ETHTOOL_GSSET_INFO``              n/a
+  ``ETHTOOL_GSSET_INFO``              ``ETHTOOL_MSG_STRSET_GET``
   ``ETHTOOL_GRXFHINDIR``              n/a
   ``ETHTOOL_SRXFHINDIR``              n/a
   ``ETHTOOL_GFEATURES``               n/a