[RFC PATCH net-next v3 10/21] ethtool: provide string sets with GET_STRSET request

[Michal Kubecek]

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. 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

It's possible to request all string sets of given type or only specific
sets. With ETHA_STRSET_COUNTS flag, only set sizes (number of strings) are
returned.

Signed-off-by: Michal Kubecek <mkubecek@xxxxxxx>
---
 Documentation/networking/ethtool-netlink.txt |  46 +-
 include/uapi/linux/ethtool.h                 |   2 +
 include/uapi/linux/ethtool_netlink.h         |  43 ++
 net/ethtool/Makefile                         |   2 +-
 net/ethtool/netlink.c                        |  10 +
 net/ethtool/strset.c                         | 437 +++++++++++++++++++
 6 files changed, 537 insertions(+), 3 deletions(-)
 create mode 100644 net/ethtool/strset.c

diff --git a/Documentation/networking/ethtool-netlink.txt b/Documentation/networking/ethtool-netlink.txt
index b79c26b5e92b..f0fe4f50db9f 100644
--- a/Documentation/networking/ethtool-netlink.txt
+++ b/Documentation/networking/ethtool-netlink.txt
@@ -126,6 +126,8 @@ List of message types
 ---------------------
 
     ETHNL_CMD_EVENT			notification only
+    ETHNL_CMD_GET_STRSET
+    ETHNL_CMD_SET_STRSET		response only
 
 All constants use ETHNL_CMD_ prefix, usually followed by "GET", "SET" or "ACT"
 to indicate the type.
@@ -166,6 +168,46 @@ and also multiple events of the same type (e.g. two or more newly registered
 devices).
 
 
+GET_STRSET
+----------
+
+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 SET_STRSET 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:
+
+    ETHA_STRSET_DEV		(nested)	device identification
+    ETHA_STRSET_COUNTS		(flag)		request only string counts
+    ETHA_STRSET_STRINGSET	(nested)	string set to request
+        ETHA_STRINGSET_ID		(u32)		set id
+
+Kernel response contents:
+
+    ETHA_STRSET_DEV		(nested)	device identification
+    ETHA_STRSET_STRINGSET	(nested)	string set to request
+        ETHA_STRINGSET_ID		(u32)		set id
+        ETHA_STRINGSET_COUNT		(u32)		number of strings
+        ETHA_STRINGSET_STRINGS		(nested)	array of strings
+            ETHA_STRING_INDEX			(u32)		string index
+            ETHA_STRING_VALUE			(string)	string value
+
+ETHA_STRSET_DEV, if present, identifies the device to request device specific
+string sets for. Depending on its presence a and NLM_F_DUMP flag, there are
+three type of GET_STRSET 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 ETHA_STRSET_STRINGSET attribute, all string sets of requested
+type are returned, otherwise only those specified in the request. Flag
+ETHA_STRSET_COUNTS tells kernel to only return string counts of the sets, not
+the actual strings.
+
+
 Request translation
 -------------------
 
@@ -200,7 +242,7 @@ ETHTOOL_STXCSUM			n/a
 ETHTOOL_GSG			n/a
 ETHTOOL_SSG			n/a
 ETHTOOL_TEST			n/a
-ETHTOOL_GSTRINGS		n/a
+ETHTOOL_GSTRINGS		ETHNL_CMD_GET_STRSET
 ETHTOOL_PHYS_ID			n/a
 ETHTOOL_GSTATS			n/a
 ETHTOOL_GTSO			n/a
@@ -228,7 +270,7 @@ ETHTOOL_FLASHDEV		n/a
 ETHTOOL_RESET			n/a
 ETHTOOL_SRXNTUPLE		n/a
 ETHTOOL_GRXNTUPLE		n/a
-ETHTOOL_GSSET_INFO		n/a
+ETHTOOL_GSSET_INFO		ETHNL_CMD_GET_STRSET
 ETHTOOL_GRXFHINDIR		n/a
 ETHTOOL_SRXFHINDIR		n/a
 ETHTOOL_GFEATURES		n/a
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 17be76aeb468..9ea278961d80 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -574,6 +574,8 @@ enum ethtool_stringset {
 	ETH_SS_TUNABLES,
 	ETH_SS_PHY_STATS,
 	ETH_SS_PHY_TUNABLES,
+
+	ETH_SS_COUNT
 };
 
 /**
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 7e192ad8ce3a..630b66732dc9 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -8,6 +8,8 @@
 enum {
 	ETHNL_CMD_NOOP,
 	ETHNL_CMD_EVENT,		/* only for notifications */
+	ETHNL_CMD_GET_STRSET,
+	ETHNL_CMD_SET_STRSET,		/* only for reply */
 
 	__ETHNL_CMD_CNT,
 	ETHNL_CMD_MAX = (__ETHNL_CMD_CNT - 1)
@@ -92,6 +94,47 @@ enum {
 	ETHA_EVENT_MAX = (__ETHA_EVENT_CNT - 1)
 };
 
+/* string sets */
+
+enum {
+	ETHA_STRING_UNSPEC,
+	ETHA_STRING_INDEX,			/* u32 */
+	ETHA_STRING_VALUE,			/* string */
+
+	__ETHA_STRING_CNT,
+	ETHA_STRING_MAX = (__ETHA_STRING_CNT - 1)
+};
+
+enum {
+	ETHA_STRINGS_UNSPEC,
+	ETHA_STRINGS_STRING,			/* nest - ETHA_STRINGS_* */
+
+	__ETHA_STRINGS_CNT,
+	ETHA_STRINGS_MAX = (__ETHA_STRINGS_CNT - 1)
+};
+
+enum {
+	ETHA_STRINGSET_UNSPEC,
+	ETHA_STRINGSET_ID,			/* u32 */
+	ETHA_STRINGSET_COUNT,			/* u32 */
+	ETHA_STRINGSET_STRINGS,			/* nest - ETHA_STRINGS_* */
+
+	__ETHA_STRINGSET_CNT,
+	ETHA_STRINGSET_MAX = (__ETHA_STRINGSET_CNT - 1)
+};
+
+/* GET_STRINGSET / SET_STRINGSET */
+
+enum {
+	ETHA_STRSET_UNSPEC,
+	ETHA_STRSET_DEV,			/* nest - ETHA_DEV_* */
+	ETHA_STRSET_COUNTS,			/* flag */
+	ETHA_STRSET_STRINGSET,			/* nest - ETHA_STRSET_* */
+
+	__ETHA_STRSET_CNT,
+	ETHA_STRSET_MAX = (__ETHA_STRSET_CNT - 1)
+};
+
 /* generic netlink info */
 #define ETHTOOL_GENL_NAME "ethtool"
 #define ETHTOOL_GENL_VERSION 1
diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index 11782306593b..11ceb00821b3 100644
--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile
@@ -4,4 +4,4 @@ obj-y				+= ioctl.o common.o
 
 obj-$(CONFIG_ETHTOOL_NETLINK)	+= ethtool_nl.o
 
-ethtool_nl-y	:= netlink.o bitset.o
+ethtool_nl-y	:= netlink.o bitset.o strset.o
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 8cdb6f52cb4a..082a9f2aa0a7 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -86,7 +86,10 @@ int ethnl_fill_dev(struct sk_buff *msg, struct net_device *dev, u16 attrtype)
 
 /* GET request helpers */
 
+extern const struct get_request_ops strset_request_ops;
+
 const struct get_request_ops *get_requests[__ETHNL_CMD_CNT] = {
+	[ETHNL_CMD_GET_STRSET]		= &strset_request_ops,
 };
 
 static struct common_req_info *alloc_get_data(const struct get_request_ops *ops)
@@ -498,6 +501,13 @@ static struct notifier_block ethnl_netdev_notifier = {
 /* genetlink setup */
 
 static const struct genl_ops ethtool_genl_ops[] = {
+	{
+		.cmd	= ETHNL_CMD_GET_STRSET,
+		.doit	= ethnl_get_doit,
+		.start	= ethnl_get_start,
+		.dumpit	= ethnl_get_dumpit,
+		.done	= ethnl_get_done,
+	},
 };
 
 static const struct genl_multicast_group ethtool_nl_mcgrps[] = {
diff --git a/net/ethtool/strset.c b/net/ethtool/strset.c
new file mode 100644
index 000000000000..a7d0ec2865fb
--- /dev/null
+++ b/net/ethtool/strset.c
@@ -0,0 +1,437 @@
+// SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
+
+#include <linux/ethtool.h>
+#include <linux/phy.h>
+#include "netlink.h"
+#include "common.h"
+
+enum strset_type {
+	ETH_SS_TYPE_NONE,
+	ETH_SS_TYPE_LEGACY,
+	ETH_SS_TYPE_SIMPLE,
+};
+
+struct strset_info {
+	enum strset_type type;
+	bool per_dev;
+	bool free_data;
+	unsigned int count;
+	union {
+		const char (*legacy)[ETH_GSTRING_LEN];
+		const char * const *simple;
+		void *ptr;
+	} data;
+};
+
+static const struct strset_info info_template[] = {
+	[ETH_SS_TEST] = {
+		.type		= ETH_SS_TYPE_LEGACY,
+		.per_dev	= true,
+	},
+	[ETH_SS_STATS] = {
+		.type		= ETH_SS_TYPE_LEGACY,
+		.per_dev	= true,
+	},
+	[ETH_SS_PRIV_FLAGS] = {
+		.type		= ETH_SS_TYPE_LEGACY,
+		.per_dev	= true,
+	},
+	[ETH_SS_NTUPLE_FILTERS] = {
+		.type		= ETH_SS_TYPE_NONE,
+	},
+	[ETH_SS_FEATURES] = {
+		.type		= ETH_SS_TYPE_LEGACY,
+		.per_dev	= false,
+		.count		= ARRAY_SIZE(netdev_features_strings),
+		.data		= { .legacy = netdev_features_strings },
+	},
+	[ETH_SS_RSS_HASH_FUNCS] = {
+		.type		= ETH_SS_TYPE_LEGACY,
+		.per_dev	= false,
+		.count		= ARRAY_SIZE(rss_hash_func_strings),
+		.data		= { .legacy = rss_hash_func_strings },
+	},
+	[ETH_SS_TUNABLES] = {
+		.type		= ETH_SS_TYPE_LEGACY,
+		.per_dev	= false,
+		.count		= ARRAY_SIZE(tunable_strings),
+		.data		= { .legacy = tunable_strings },
+	},
+	[ETH_SS_PHY_STATS] = {
+		.type		= ETH_SS_TYPE_LEGACY,
+		.per_dev	= true,
+	},
+	[ETH_SS_PHY_TUNABLES] = {
+		.type		= ETH_SS_TYPE_LEGACY,
+		.per_dev	= false,
+		.count		= ARRAY_SIZE(phy_tunable_strings),
+		.data		= { .legacy = phy_tunable_strings },
+	},
+};
+
+struct strset_data {
+	struct common_req_info		reqinfo_base;
+	u32				req_ids;
+	bool				counts_only;
+
+	/* everything below here will be reset for each device in dumps */
+	struct common_reply_data	repdata_base;
+	struct strset_info		info[ETH_SS_COUNT];
+};
+
+static const struct nla_policy get_strset_policy[ETHA_STRSET_MAX + 1] = {
+	[ETHA_STRSET_UNSPEC]		= { .type = NLA_REJECT },
+	[ETHA_STRSET_DEV]		= { .type = NLA_NESTED },
+	[ETHA_STRSET_COUNTS]		= { .type = NLA_FLAG },
+	[ETHA_STRSET_STRINGSET]		= { .type = NLA_NESTED },
+};
+
+static const struct nla_policy stringset_policy[ETHA_STRINGSET_MAX + 1] = {
+	[ETHA_STRINGSET_UNSPEC]		= { .type = NLA_REJECT },
+	[ETHA_STRINGSET_ID]		= { .type = NLA_U32 },
+	[ETHA_STRINGSET_COUNT]		= { .type = NLA_REJECT },
+	[ETHA_STRINGSET_STRINGS]	= { .type = NLA_REJECT },
+};
+
+static bool id_requested(const struct strset_data *data, u32 id)
+{
+	return data->req_ids & (1U << id);
+}
+
+static bool include_set(const struct strset_data *data, u32 id)
+{
+	bool per_dev;
+
+	BUILD_BUG_ON(ETH_SS_COUNT >= BITS_PER_BYTE * sizeof(data->req_ids));
+
+	if (data->req_ids)
+		return id_requested(data, id);
+
+	per_dev = data->info[id].per_dev;
+	if (data->info[id].type == ETH_SS_TYPE_NONE)
+		return false;
+	return data->repdata_base.dev ? per_dev : !per_dev;
+}
+
+const char *str_value(const struct strset_info *info, unsigned int i)
+{
+	switch (info->type) {
+	case ETH_SS_TYPE_LEGACY:
+		return info->data.legacy[i];
+	case ETH_SS_TYPE_SIMPLE:
+		return info->data.simple[i];
+	default:
+		WARN_ONCE(1, "unexpected string set type");
+		return "";
+	}
+}
+
+static int get_strset_id(const struct nlattr *nest, u32 *val,
+			 struct genl_info *info)
+{
+	struct nlattr *tb[ETHA_STRINGSET_MAX + 1];
+	int ret;
+
+	ret = nla_parse_nested(tb, ETHA_STRINGSET_MAX, nest, stringset_policy,
+			       info ? info->extack : NULL);
+	if (ret < 0)
+		return ret;
+	if (!tb[ETHA_STRINGSET_ID])
+		return -EINVAL;
+
+	*val = nla_get_u32(tb[ETHA_STRINGSET_ID]);
+	return 0;
+}
+
+static int parse_strset(struct common_req_info *req_info, struct sk_buff *skb,
+			struct genl_info *info, const struct nlmsghdr *nlhdr)
+{
+	struct strset_data *data =
+		container_of(req_info, struct strset_data, reqinfo_base);
+	struct nlattr *attr;
+	int rem, ret;
+
+	ret = nlmsg_validate(nlhdr, GENL_HDRLEN, ETHA_STRSET_MAX,
+			     get_strset_policy, info ? info->extack : NULL);
+	if (ret < 0)
+		return ret;
+
+	nlmsg_for_each_attr(attr, nlhdr, GENL_HDRLEN, rem) {
+		u32 id;
+
+		switch (nla_type(attr)) {
+		case ETHA_STRSET_DEV:
+			req_info->dev = ethnl_dev_get(info, attr);
+			if (IS_ERR(req_info->dev)) {
+				ret = PTR_ERR(req_info->dev);
+				req_info->dev = NULL;
+				return ret;
+			}
+			break;
+		case ETHA_STRSET_COUNTS:
+			data->counts_only = true;
+			break;
+		case ETHA_STRSET_STRINGSET:
+			ret = get_strset_id(attr, &id, info);
+			if (ret < 0)
+				return ret;
+			if (ret >= ETH_SS_COUNT)
+				return -EOPNOTSUPP;
+			data->req_ids |= (1U << id);
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static void free_strset(struct strset_data *data)
+{
+	unsigned int i;
+
+	for (i = 0; i < ETH_SS_COUNT; i++)
+		if (data->info[i].free_data) {
+			kfree(data->info[i].data.ptr);
+			data->info[i].data.ptr = NULL;
+			data->info[i].free_data = false;
+		}
+}
+
+static int prepare_one_stringset(struct strset_info *info,
+				 struct net_device *dev, unsigned int id,
+				 bool counts_only)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	void *strings;
+	int count, ret;
+
+	if (id == ETH_SS_PHY_STATS && dev->phydev &&
+	    !ops->get_ethtool_phy_stats)
+		ret = phy_ethtool_get_sset_count(dev->phydev);
+	else if (ops->get_sset_count && ops->get_strings)
+		ret = ops->get_sset_count(dev, id);
+	else
+		ret = -EOPNOTSUPP;
+	if (ret <= 0) {
+		info->count = 0;
+		return 0;
+	}
+
+	count = ret;
+	if (!counts_only) {
+		strings = kcalloc(count, ETH_GSTRING_LEN, GFP_KERNEL);
+		if (!strings)
+			return -ENOMEM;
+		if (id == ETH_SS_PHY_STATS && dev->phydev &&
+		    !ops->get_ethtool_phy_stats)
+			phy_ethtool_get_strings(dev->phydev, strings);
+		else
+			ops->get_strings(dev, id, strings);
+		info->data.legacy = strings;
+		info->free_data = true;
+	}
+	info->count = count;
+
+	return 0;
+}
+
+static int prepare_strset(struct common_req_info *req_info,
+			  struct genl_info *info)
+{
+	struct strset_data *data =
+		container_of(req_info, struct strset_data, reqinfo_base);
+	struct net_device *dev = data->repdata_base.dev;
+	unsigned int i;
+	int ret;
+
+	memcpy(&data->info, &info_template, sizeof(data->info));
+
+	if (!dev) {
+		for (i = 0; i < ETH_SS_COUNT; i++) {
+			if (id_requested(data, i) &&
+			    data->info[i].per_dev) {
+				ETHNL_SET_ERRMSG(info,
+						 "requested per device strings without dev");
+				return -EINVAL;
+			}
+		}
+	}
+
+	ret = ethnl_before_ops(dev);
+	if (ret < 0)
+		goto err_strset;
+	for (i = 0; i < ETH_SS_COUNT; i++) {
+		if (!include_set(data, i) || !data->info[i].per_dev)
+			continue;
+		if (WARN_ONCE(data->info[i].type != ETH_SS_TYPE_LEGACY,
+			      "unexpected string set type %u",
+			      data->info[i].type))
+			goto err_ops;
+
+		ret = prepare_one_stringset(&data->info[i], dev, i,
+					    data->counts_only);
+		if (ret < 0)
+			goto err_ops;
+	}
+	ethnl_after_ops(dev);
+
+	return 0;
+err_ops:
+	ethnl_after_ops(dev);
+err_strset:
+	free_strset(data);
+	return ret;
+}
+
+static int legacy_set_size(const char (*set)[ETH_GSTRING_LEN],
+			   unsigned int count)
+{
+	unsigned int len = 0;
+	unsigned int i;
+
+	for (i = 0; i < count; i++)
+		len += nla_total_size(nla_total_size(sizeof(u32)) +
+				      ethnl_str_size(set[i]));
+	len = 2 * nla_total_size(sizeof(u32)) + nla_total_size(len);
+
+	return nla_total_size(len);
+}
+
+static int simple_set_size(const char * const *set, unsigned int count)
+{
+	unsigned int len = 0;
+	unsigned int i;
+
+	for (i = 0; i < count; i++)
+		len += nla_total_size(nla_total_size(sizeof(u32)) +
+				      ethnl_str_size(set[i]));
+	len = 2 * nla_total_size(sizeof(u32)) + nla_total_size(len);
+
+	return nla_total_size(len);
+}
+
+static int set_size(const struct strset_info *info, bool counts_only)
+{
+	if (info->count == 0)
+		return 0;
+	if (counts_only)
+		return nla_total_size(2 * nla_total_size(sizeof(u32)));
+
+	switch (info->type) {
+	case ETH_SS_TYPE_LEGACY:
+		return legacy_set_size(info->data.legacy, info->count);
+	case ETH_SS_TYPE_SIMPLE:
+		return simple_set_size(info->data.simple, info->count);
+	default:
+		return -EINVAL;
+	};
+}
+
+static int strset_size(const struct common_req_info *req_info)
+{
+	const struct strset_data *data =
+		container_of(req_info, struct strset_data, reqinfo_base);
+	unsigned int i;
+	int len = 0;
+	int ret;
+
+	len += dev_ident_size();
+	for (i = 0; i < ETH_SS_COUNT; i++) {
+		const struct strset_info *info = &data->info[i];
+
+		if (!include_set(data, i) || info->type == ETH_SS_TYPE_NONE)
+			continue;
+
+		ret = set_size(info, data->counts_only);
+		if (ret < 0)
+			return ret;
+		len += ret;
+	}
+
+	return len;
+}
+
+static int fill_string(struct sk_buff *skb, const struct strset_info *info,
+		       u32 idx)
+{
+	struct nlattr *string = ethnl_nest_start(skb, ETHA_STRINGS_STRING);
+
+	if (!string)
+		return -EMSGSIZE;
+	if (nla_put_u32(skb, ETHA_STRING_INDEX, idx) ||
+	    nla_put_string(skb, ETHA_STRING_VALUE, str_value(info, idx)))
+		return -EMSGSIZE;
+	nla_nest_end(skb, string);
+
+	return 0;
+}
+
+static int fill_set(struct sk_buff *skb, const struct strset_data *data, u32 id)
+{
+	const struct strset_info *info = &data->info[id];
+	struct nlattr *strings;
+	struct nlattr *nest;
+	unsigned int i = (unsigned int)(-1);
+
+	if (info->type == ETH_SS_TYPE_NONE)
+		return -EOPNOTSUPP;
+	if (info->count == 0)
+		return 0;
+	nest = ethnl_nest_start(skb, ETHA_STRSET_STRINGSET);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, ETHA_STRINGSET_ID, id) ||
+	    nla_put_u32(skb, ETHA_STRINGSET_COUNT, info->count))
+		goto err;
+
+	if (!data->counts_only) {
+		strings = ethnl_nest_start(skb, ETHA_STRINGSET_STRINGS);
+		if (!strings)
+			goto err;
+		for (i = 0; i < info->count; i++) {
+			if (fill_string(skb, info, i) < 0)
+				goto err;
+		}
+		nla_nest_end(skb, strings);
+	}
+
+	nla_nest_end(skb, nest);
+	return 0;
+
+err:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
+}
+
+static int fill_strset(struct sk_buff *skb,
+		       const struct common_req_info *req_info)
+{
+	const struct strset_data *data =
+		container_of(req_info, struct strset_data, reqinfo_base);
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < ETH_SS_COUNT; i++)
+		if (include_set(data, i)) {
+			ret = fill_set(skb, data, i);
+			if (ret < 0)
+				return ret;
+		}
+
+	return 0;
+}
+
+const struct get_request_ops strset_request_ops = {
+	.request_cmd		= ETHNL_CMD_GET_STRSET,
+	.reply_cmd		= ETHNL_CMD_SET_STRSET,
+	.dev_attrtype		= ETHA_STRSET_DEV,
+	.data_size		= sizeof(struct strset_data),
+	.repdata_offset		= offsetof(struct strset_data, repdata_base),
+	.allow_nodev_do		= true,
+
+	.parse_request		= parse_strset,
+	.prepare_data		= prepare_strset,
+	.reply_size		= strset_size,
+	.fill_reply		= fill_strset,
+};
-- 
2.20.1