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>

4 files changed, 438 insertions, 1 deletions

diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index a7e6c2c85db9..efcc42c34d62 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 ae63e8423072..7dc082bde670 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -194,6 +194,7 @@ struct ethnl_dump_ctx {
 
 static const struct ethnl_request_ops *
 ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
+	[ETHTOOL_MSG_STRSET_GET]	= &ethnl_strset_request_ops,
 };
 
 static struct ethnl_dump_ctx *ethnl_dump_context(struct netlink_callback *cb)
@@ -518,6 +519,13 @@ EXPORT_SYMBOL(ethtool_notify);
 /* genetlink setup */
 
 static const struct genl_ops ethtool_genl_ops[] = {
+	{
+		.cmd	= ETHTOOL_MSG_STRSET_GET,
+		.doit	= ethnl_default_doit,
+		.start	= ethnl_default_start,
+		.dumpit	= ethnl_default_dumpit,
+		.done	= ethnl_default_done,
+	},
 };
 
 static const struct genl_multicast_group ethtool_nl_mcgrps[] = {
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index 6ec0dd06277f..44e9f63aefb7 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -326,4 +326,8 @@ struct ethnl_request_ops {
 	void (*cleanup_data)(struct ethnl_reply_data *reply_data);
 };
 
+/* request handlers */
+
+extern const struct ethnl_request_ops ethnl_strset_request_ops;
+
 #endif /* _NET_ETHTOOL_NETLINK_H */
diff --git a/net/ethtool/strset.c b/net/ethtool/strset.c
new file mode 100644
index 000000000000..9f2243329015
--- /dev/null
+++ b/net/ethtool/strset.c
@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/ethtool.h>
+#include <linux/phy.h>
+#include "netlink.h"
+#include "common.h"
+
+struct strset_info {
+	bool per_dev;
+	bool free_strings;
+	unsigned int count;
+	const char (*strings)[ETH_GSTRING_LEN];
+};
+
+static const struct strset_info info_template[] = {
+	[ETH_SS_TEST] = {
+		.per_dev	= true,
+	},
+	[ETH_SS_STATS] = {
+		.per_dev	= true,
+	},
+	[ETH_SS_PRIV_FLAGS] = {
+		.per_dev	= true,
+	},
+	[ETH_SS_FEATURES] = {
+		.per_dev	= false,
+		.count		= ARRAY_SIZE(netdev_features_strings),
+		.strings	= netdev_features_strings,
+	},
+	[ETH_SS_RSS_HASH_FUNCS] = {
+		.per_dev	= false,
+		.count		= ARRAY_SIZE(rss_hash_func_strings),
+		.strings	= rss_hash_func_strings,
+	},
+	[ETH_SS_TUNABLES] = {
+		.per_dev	= false,
+		.count		= ARRAY_SIZE(tunable_strings),
+		.strings	= tunable_strings,
+	},
+	[ETH_SS_PHY_STATS] = {
+		.per_dev	= true,
+	},
+	[ETH_SS_PHY_TUNABLES] = {
+		.per_dev	= false,
+		.count		= ARRAY_SIZE(phy_tunable_strings),
+		.strings	= phy_tunable_strings,
+	},
+	[ETH_SS_LINK_MODES] = {
+		.per_dev	= false,
+		.count		= __ETHTOOL_LINK_MODE_MASK_NBITS,
+		.strings	= link_mode_names,
+	},
+};
+
+struct strset_req_info {
+	struct ethnl_req_info		base;
+	u32				req_ids;
+	bool				counts_only;
+};
+
+#define STRSET_REQINFO(__req_base) \
+	container_of(__req_base, struct strset_req_info, base)
+
+struct strset_reply_data {
+	struct ethnl_reply_data		base;
+	struct strset_info		sets[ETH_SS_COUNT];
+};
+
+#define STRSET_REPDATA(__reply_base) \
+	container_of(__reply_base, struct strset_reply_data, base)
+
+static const struct nla_policy strset_get_policy[ETHTOOL_A_STRSET_MAX + 1] = {
+	[ETHTOOL_A_STRSET_UNSPEC]	= { .type = NLA_REJECT },
+	[ETHTOOL_A_STRSET_HEADER]	= { .type = NLA_NESTED },
+	[ETHTOOL_A_STRSET_STRINGSETS]	= { .type = NLA_NESTED },
+};
+
+static const struct nla_policy
+get_stringset_policy[ETHTOOL_A_STRINGSET_MAX + 1] = {
+	[ETHTOOL_A_STRINGSET_UNSPEC]	= { .type = NLA_REJECT },
+	[ETHTOOL_A_STRINGSET_ID]	= { .type = NLA_U32 },
+	[ETHTOOL_A_STRINGSET_COUNT]	= { .type = NLA_REJECT },
+	[ETHTOOL_A_STRINGSET_STRINGS]	= { .type = NLA_REJECT },
+};
+
+/**
+ * strset_include() - test if a string set should be included in reply
+ * @data: pointer to request data structure
+ * @id:   id of string set to check (ETH_SS_* constants)
+ */
+static bool strset_include(const struct strset_req_info *info,
+			   const struct strset_reply_data *data, u32 id)
+{
+	bool per_dev;
+
+	BUILD_BUG_ON(ETH_SS_COUNT >= BITS_PER_BYTE * sizeof(info->req_ids));
+
+	if (info->req_ids)
+		return info->req_ids & (1U << id);
+	per_dev = data->sets[id].per_dev;
+	if (!per_dev && !data->sets[id].strings)
+		return false;
+
+	return data->base.dev ? per_dev : !per_dev;
+}
+
+static int strset_get_id(const struct nlattr *nest, u32 *val,
+			 struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[ETHTOOL_A_STRINGSET_MAX + 1];
+	int ret;
+
+	ret = nla_parse_nested(tb, ETHTOOL_A_STRINGSET_MAX, nest,
+			       get_stringset_policy, extack);
+	if (ret < 0)
+		return ret;
+	if (!tb[ETHTOOL_A_STRINGSET_ID])
+		return -EINVAL;
+
+	*val = nla_get_u32(tb[ETHTOOL_A_STRINGSET_ID]);
+	return 0;
+}
+
+static const struct nla_policy
+strset_stringsets_policy[ETHTOOL_A_STRINGSETS_MAX + 1] = {
+	[ETHTOOL_A_STRINGSETS_UNSPEC]		= { .type = NLA_REJECT },
+	[ETHTOOL_A_STRINGSETS_STRINGSET]	= { .type = NLA_NESTED },
+};
+
+static int strset_parse_request(struct ethnl_req_info *req_base,
+				struct nlattr **tb,
+				struct netlink_ext_ack *extack)
+{
+	struct strset_req_info *req_info = STRSET_REQINFO(req_base);
+	struct nlattr *nest = tb[ETHTOOL_A_STRSET_STRINGSETS];
+	struct nlattr *attr;
+	int rem, ret;
+
+	if (!nest)
+		return 0;
+	ret = nla_validate_nested(nest, ETHTOOL_A_STRINGSETS_MAX,
+				  strset_stringsets_policy, extack);
+	if (ret < 0)
+		return ret;
+
+	req_info->counts_only = tb[ETHTOOL_A_STRSET_COUNTS_ONLY];
+	nla_for_each_nested(attr, nest, rem) {
+		u32 id;
+
+		if (WARN_ONCE(nla_type(attr) != ETHTOOL_A_STRINGSETS_STRINGSET,
+			      "unexpected attrtype %u in ETHTOOL_A_STRSET_STRINGSETS\n",
+			      nla_type(attr)))
+			return -EINVAL;
+
+		ret = strset_get_id(attr, &id, extack);
+		if (ret < 0)
+			return ret;
+		if (ret >= ETH_SS_COUNT) {
+			NL_SET_ERR_MSG_ATTR(extack, attr,
+					    "unknown string set id");
+			return -EOPNOTSUPP;
+		}
+
+		req_info->req_ids |= (1U << id);
+	}
+
+	return 0;
+}
+
+static void strset_cleanup_data(struct ethnl_reply_data *reply_base)
+{
+	struct strset_reply_data *data = STRSET_REPDATA(reply_base);
+	unsigned int i;
+
+	for (i = 0; i < ETH_SS_COUNT; i++)
+		if (data->sets[i].free_strings) {
+			kfree(data->sets[i].strings);
+			data->sets[i].strings = NULL;
+			data->sets[i].free_strings = false;
+		}
+}
+
+static int strset_prepare_set(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->strings = strings;
+		info->free_strings = true;
+	}
+	info->count = count;
+
+	return 0;
+}
+
+static int strset_prepare_data(const struct ethnl_req_info *req_base,
+			       struct ethnl_reply_data *reply_base,
+			       struct genl_info *info)
+{
+	const struct strset_req_info *req_info = STRSET_REQINFO(req_base);
+	struct strset_reply_data *data = STRSET_REPDATA(reply_base);
+	struct net_device *dev = reply_base->dev;
+	unsigned int i;
+	int ret;
+
+	BUILD_BUG_ON(ARRAY_SIZE(info_template) != ETH_SS_COUNT);
+	memcpy(&data->sets, &info_template, sizeof(data->sets));
+
+	if (!dev) {
+		for (i = 0; i < ETH_SS_COUNT; i++) {
+			if ((req_info->req_ids & (1U << i)) &&
+			    data->sets[i].per_dev) {
+				if (info)
+					GENL_SET_ERR_MSG(info, "requested per device strings without dev");
+				return -EINVAL;
+			}
+		}
+	}
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		goto err_strset;
+	for (i = 0; i < ETH_SS_COUNT; i++) {
+		if (!strset_include(req_info, data, i) ||
+		    !data->sets[i].per_dev)
+			continue;
+
+		ret = strset_prepare_set(&data->sets[i], dev, i,
+					 req_info->counts_only);
+		if (ret < 0)
+			goto err_ops;
+	}
+	ethnl_ops_complete(dev);
+
+	return 0;
+err_ops:
+	ethnl_ops_complete(dev);
+err_strset:
+	strset_cleanup_data(reply_base);
+	return ret;
+}
+
+/* calculate size of ETHTOOL_A_STRSET_STRINGSET nest for one string set */
+static int strset_set_size(const struct strset_info *info, bool counts_only)
+{
+	unsigned int len = 0;
+	unsigned int i;
+
+	if (info->count == 0)
+		return 0;
+	if (counts_only)
+		return nla_total_size(2 * nla_total_size(sizeof(u32)));
+
+	for (i = 0; i < info->count; i++) {
+		const char *str = info->strings[i];
+
+		/* ETHTOOL_A_STRING_INDEX, ETHTOOL_A_STRING_VALUE, nest */
+		len += nla_total_size(nla_total_size(sizeof(u32)) +
+				      ethnl_strz_size(str));
+	}
+	/* ETHTOOL_A_STRINGSET_ID, ETHTOOL_A_STRINGSET_COUNT */
+	len = 2 * nla_total_size(sizeof(u32)) + nla_total_size(len);
+
+	return nla_total_size(len);
+}
+
+static int strset_reply_size(const struct ethnl_req_info *req_base,
+			     const struct ethnl_reply_data *reply_base)
+{
+	const struct strset_req_info *req_info = STRSET_REQINFO(req_base);
+	const struct strset_reply_data *data = STRSET_REPDATA(reply_base);
+	unsigned int i;
+	int len = 0;
+	int ret;
+
+	len += ethnl_reply_header_size();
+	for (i = 0; i < ETH_SS_COUNT; i++) {
+		const struct strset_info *set_info = &data->sets[i];
+
+		if (!strset_include(req_info, data, i))
+			continue;
+
+		ret = strset_set_size(set_info, req_info->counts_only);
+		if (ret < 0)
+			return ret;
+		len += ret;
+	}
+
+	return len;
+}
+
+/* fill one string into reply */
+static int strset_fill_string(struct sk_buff *skb,
+			      const struct strset_info *set_info, u32 idx)
+{
+	struct nlattr *string_attr;
+	const char *value;
+
+	value = set_info->strings[idx];
+
+	string_attr = nla_nest_start(skb, ETHTOOL_A_STRINGS_STRING);
+	if (!string_attr)
+		return -EMSGSIZE;
+	if (nla_put_u32(skb, ETHTOOL_A_STRING_INDEX, idx) ||
+	    ethnl_put_strz(skb, ETHTOOL_A_STRING_VALUE, value))
+		goto nla_put_failure;
+	nla_nest_end(skb, string_attr);
+
+	return 0;
+nla_put_failure:
+	nla_nest_cancel(skb, string_attr);
+	return -EMSGSIZE;
+}
+
+/* fill one string set into reply */
+static int strset_fill_set(struct sk_buff *skb,
+			   const struct strset_info *set_info, u32 id,
+			   bool counts_only)
+{
+	struct nlattr *stringset_attr;
+	struct nlattr *strings_attr;
+	unsigned int i;
+
+	if (!set_info->per_dev && !set_info->strings)
+		return -EOPNOTSUPP;
+	if (set_info->count == 0)
+		return 0;
+	stringset_attr = nla_nest_start(skb, ETHTOOL_A_STRINGSETS_STRINGSET);
+	if (!stringset_attr)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, ETHTOOL_A_STRINGSET_ID, id) ||
+	    nla_put_u32(skb, ETHTOOL_A_STRINGSET_COUNT, set_info->count))
+		goto nla_put_failure;
+
+	if (!counts_only) {
+		strings_attr = nla_nest_start(skb, ETHTOOL_A_STRINGSET_STRINGS);
+		if (!strings_attr)
+			goto nla_put_failure;
+		for (i = 0; i < set_info->count; i++) {
+			if (strset_fill_string(skb, set_info, i) < 0)
+				goto nla_put_failure;
+		}
+		nla_nest_end(skb, strings_attr);
+	}
+
+	nla_nest_end(skb, stringset_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, stringset_attr);
+	return -EMSGSIZE;
+}
+
+static int strset_fill_reply(struct sk_buff *skb,
+			     const struct ethnl_req_info *req_base,
+			     const struct ethnl_reply_data *reply_base)
+{
+	const struct strset_req_info *req_info = STRSET_REQINFO(req_base);
+	const struct strset_reply_data *data = STRSET_REPDATA(reply_base);
+	struct nlattr *nest;
+	unsigned int i;
+	int ret;
+
+	nest = nla_nest_start(skb, ETHTOOL_A_STRSET_STRINGSETS);
+	if (!nest)
+		return -EMSGSIZE;
+
+	for (i = 0; i < ETH_SS_COUNT; i++) {
+		if (strset_include(req_info, data, i)) {
+			ret = strset_fill_set(skb, &data->sets[i], i,
+					      req_info->counts_only);
+			if (ret < 0)
+				goto nla_put_failure;
+		}
+	}
+
+	nla_nest_end(skb, nest);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, nest);
+	return ret;
+}
+
+const struct ethnl_request_ops ethnl_strset_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_STRSET_GET,
+	.reply_cmd		= ETHTOOL_MSG_STRSET_GET_REPLY,
+	.hdr_attr		= ETHTOOL_A_STRSET_HEADER,
+	.max_attr		= ETHTOOL_A_STRSET_MAX,
+	.req_info_size		= sizeof(struct strset_req_info),
+	.reply_data_size	= sizeof(struct strset_reply_data),
+	.request_policy		= strset_get_policy,
+	.allow_nodev_do		= true,
+
+	.parse_request		= strset_parse_request,
+	.prepare_data		= strset_prepare_data,
+	.reply_size		= strset_reply_size,
+	.fill_reply		= strset_fill_reply,
+	.cleanup_data		= strset_cleanup_data,
+};