[RFC PATCH net-next v3 03/21] ethtool: introduce ethtool netlink interface

From: Michal Kubecek
Date: Mon Feb 18 2019 - 13:21:45 EST

Basic genetlink and init infrastructure for the netlink interface, register
genetlink family "ethtool". Introduce CONFIG_ETHTOOL_NETLINK Kconfig
option. Add interface description into Documentation/networking.

Signed-off-by: Michal Kubecek <mkubecek@xxxxxxx>
---
Documentation/networking/ethtool-netlink.txt | 167 +++++++++++++++++++
include/linux/ethtool_netlink.h | 9 +
include/uapi/linux/ethtool_netlink.h | 19 +++
net/Kconfig | 8 +
net/ethtool/Makefile | 6 +-
net/ethtool/netlink.c | 34 ++++
net/ethtool/netlink.h | 12 ++
7 files changed, 254 insertions(+), 1 deletion(-)
create mode 100644 Documentation/networking/ethtool-netlink.txt
create mode 100644 include/linux/ethtool_netlink.h
create mode 100644 include/uapi/linux/ethtool_netlink.h
create mode 100644 net/ethtool/netlink.c
create mode 100644 net/ethtool/netlink.h

diff --git a/Documentation/networking/ethtool-netlink.txt b/Documentation/networking/ethtool-netlink.txt
new file mode 100644
index 000000000000..09c36e0392a8
--- /dev/null
+++ b/Documentation/networking/ethtool-netlink.txt
@@ -0,0 +1,167 @@
+ 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.
+
+In requests, device can be identified by ifindex or by name; if both are used,
+they must match. In replies, kernel fills both. The meaning of flags,
+info_mask and index fields depends on request type.
+
+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 request 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 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.
+
+Some request types allow passing an attribute named ETHA_*_INFOMASK with
+a bitmask telling kernel that we are only interested in some parts of the
+information. If info mask is omitted, all available information is returned.
+Meaning of info mask bits depends on request type and is listed below.
+
+
+Device identification
+---------------------
+
+When appropriate, network device is identified by a nested attribute named
+ETHA_*_DEV. This attribute can contain
+
+ ETHA_DEV_INDEX (u32) device ifindex
+ ETHA_DEV_NAME (string) device name
+
+In device related requests, one of these is sufficient; if both are used, they
+must match (i.e. identify the same device). In device related replies both are
+provided by kernel. In dump requests, device is not specified and kernel
+replies with one message per network device (only those for which the request
+is supported).
+
+List of message types
+---------------------
+
+All constants use ETHNL_CMD_ prefix, usually followed by "GET", "SET" or "ACT"
+to indicate the type.
+
+Messages of type "get" are used by userspace to request information and
+usually do not contain any attributes (that may be added later for dump
+filtering). Kernel response is in the form of corresponding "set" message;
+the same message can be also used to set (some of) the parameters, except for
+messages marked as "response only" in the table above. "Get" messages with
+NLM_F_DUMP flags and no device identification dump the information for all
+devices supporting the request.
+
+Later sections describe the format and semantics of these request messages.
+
+
+Request translation
+-------------------
+
+The following table maps iosctl 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 n/a
+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
diff --git a/include/linux/ethtool_netlink.h b/include/linux/ethtool_netlink.h
new file mode 100644
index 000000000000..0412adb4f42f
--- /dev/null
+++ b/include/linux/ethtool_netlink.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#ifndef _LINUX_ETHTOOL_NETLINK_H_
+#define _LINUX_ETHTOOL_NETLINK_H_
+
+#include <uapi/linux/ethtool_netlink.h>
+#include <linux/ethtool.h>
+
+#endif /* _LINUX_ETHTOOL_NETLINK_H_ */
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
new file mode 100644
index 000000000000..d8a8d3c72c2f
--- /dev/null
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#ifndef _UAPI_LINUX_ETHTOOL_NETLINK_H_
+#define _UAPI_LINUX_ETHTOOL_NETLINK_H_
+
+#include <linux/ethtool.h>
+
+enum {
+ ETHNL_CMD_NOOP,
+
+ __ETHNL_CMD_CNT,
+ ETHNL_CMD_MAX = (__ETHNL_CMD_CNT - 1)
+};
+
+/* generic netlink info */
+#define ETHTOOL_GENL_NAME "ethtool"
+#define ETHTOOL_GENL_VERSION 1
+
+#endif /* _UAPI_LINUX_ETHTOOL_NETLINK_H_ */
diff --git a/net/Kconfig b/net/Kconfig
index 62da6148e9f8..383fe04ddf07 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -460,6 +460,14 @@ config FAILOVER
migration of VMs with direct attached VFs by failing over to the
paravirtual datapath when the VF is unplugged.

+config ETHTOOL_NETLINK
+ bool "Netlink interface for ethtool"
+ default y
+ help
+ An alternative userspace interface for ethtool based on generic
+ netlink. It provides better extensibility and some new features,
+ e.g. notification messages.
+
endif # if NET

# Used by archs to tell that they support BPF JIT compiler plus which flavour.
diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index 3ebfab2bca66..f30e0da88be5 100644
--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile
@@ -1,3 +1,7 @@
# SPDX-License-Identifier: GPL-2.0

-obj-y += ioctl.o
+obj-y += ioctl.o
+
+obj-$(CONFIG_ETHTOOL_NETLINK) += ethtool_nl.o
+
+ethtool_nl-y := netlink.o
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
new file mode 100644
index 000000000000..5fe3e5b68e81
--- /dev/null
+++ b/net/ethtool/netlink.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
+
+#include <linux/ethtool_netlink.h>
+#include "netlink.h"
+
+/* genetlink setup */
+
+static const struct genl_ops ethtool_genl_ops[] = {
+};
+
+struct genl_family ethtool_genl_family = {
+ .hdrsize = 0,
+ .name = ETHTOOL_GENL_NAME,
+ .version = ETHTOOL_GENL_VERSION,
+ .netnsok = true,
+ .parallel_ops = true,
+ .ops = ethtool_genl_ops,
+ .n_ops = ARRAY_SIZE(ethtool_genl_ops),
+};
+
+/* module setup */
+
+static int __init ethnl_init(void)
+{
+ int ret;
+
+ ret = genl_register_family(&ethtool_genl_family);
+ if (ret < 0)
+ panic("ethtool: could not register genetlink family\n");
+
+ return 0;
+}
+
+subsys_initcall(ethnl_init);
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
new file mode 100644
index 000000000000..63063b582ca2
--- /dev/null
+++ b/net/ethtool/netlink.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#ifndef _NET_ETHTOOL_NETLINK_H
+#define _NET_ETHTOOL_NETLINK_H
+
+#include <linux/ethtool_netlink.h>
+#include <linux/netdevice.h>
+#include <net/genetlink.h>
+
+extern struct genl_family ethtool_genl_family;
+
+#endif /* _NET_ETHTOOL_NETLINK_H */
--
2.20.1