ethtool: add a new command for reading standard stats

Add an interface for reading standard stats, including
stats which don't have a corresponding control interface.

Start with IEEE 802.3 PHY stats. There seems to be only
one stat to expose there.

Define API to not require user space changes when new
stats or groups are added. Groups are based on bitset,
stats have a string set associated.

v1: wrap stats in a nest

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 226 insertions, 1 deletions

diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index 83842685fd8c..723c9a8a8cdf 100644
--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile
@@ -7,4 +7,4 @@ obj-$(CONFIG_ETHTOOL_NETLINK)	+= ethtool_nl.o
 ethtool_nl-y	:= netlink.o bitset.o strset.o linkinfo.o linkmodes.o \
 		   linkstate.o debug.o wol.o features.o privflags.o rings.o \
 		   channels.o coalesce.o pause.o eee.o tsinfo.o cabletest.o \
-		   tunnels.o fec.o eeprom.o
+		   tunnels.o fec.o eeprom.o stats.o
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 5f5d7c4b3d4a..290012d0d11d 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -247,6 +247,7 @@ ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
 	[ETHTOOL_MSG_FEC_GET]		= &ethnl_fec_request_ops,
 	[ETHTOOL_MSG_TSINFO_GET]	= &ethnl_tsinfo_request_ops,
 	[ETHTOOL_MSG_MODULE_EEPROM_GET]	= &ethnl_module_eeprom_request_ops,
+	[ETHTOOL_MSG_STATS_GET]		= &ethnl_stats_request_ops,
 };
 
 static struct ethnl_dump_ctx *ethnl_dump_context(struct netlink_callback *cb)
@@ -942,6 +943,15 @@ static const struct genl_ops ethtool_genl_ops[] = {
 		.policy = ethnl_module_eeprom_get_policy,
 		.maxattr = ARRAY_SIZE(ethnl_module_eeprom_get_policy) - 1,
 	},
+	{
+		.cmd	= ETHTOOL_MSG_STATS_GET,
+		.doit	= ethnl_default_doit,
+		.start	= ethnl_default_start,
+		.dumpit	= ethnl_default_dumpit,
+		.done	= ethnl_default_done,
+		.policy = ethnl_stats_get_policy,
+		.maxattr = ARRAY_SIZE(ethnl_stats_get_policy) - 1,
+	},
 };
 
 static const struct genl_multicast_group ethtool_nl_mcgrps[] = {
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index 4305ac971bb0..9d88983b6597 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -346,6 +346,7 @@ extern const struct ethnl_request_ops ethnl_eee_request_ops;
 extern const struct ethnl_request_ops ethnl_tsinfo_request_ops;
 extern const struct ethnl_request_ops ethnl_fec_request_ops;
 extern const struct ethnl_request_ops ethnl_module_eeprom_request_ops;
+extern const struct ethnl_request_ops ethnl_stats_request_ops;
 
 extern const struct nla_policy ethnl_header_policy[ETHTOOL_A_HEADER_FLAGS + 1];
 extern const struct nla_policy ethnl_header_policy_stats[ETHTOOL_A_HEADER_FLAGS + 1];
@@ -380,6 +381,7 @@ extern const struct nla_policy ethnl_tunnel_info_get_policy[ETHTOOL_A_TUNNEL_INF
 extern const struct nla_policy ethnl_fec_get_policy[ETHTOOL_A_FEC_HEADER + 1];
 extern const struct nla_policy ethnl_fec_set_policy[ETHTOOL_A_FEC_AUTO + 1];
 extern const struct nla_policy ethnl_module_eeprom_get_policy[ETHTOOL_A_MODULE_EEPROM_DATA + 1];
+extern const struct nla_policy ethnl_stats_get_policy[ETHTOOL_A_STATS_GROUPS + 1];
 
 int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info);
 int ethnl_set_linkmodes(struct sk_buff *skb, struct genl_info *info);
@@ -399,4 +401,7 @@ int ethnl_tunnel_info_start(struct netlink_callback *cb);
 int ethnl_tunnel_info_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
 int ethnl_set_fec(struct sk_buff *skb, struct genl_info *info);
 
+extern const char stats_std_names[__ETHTOOL_STATS_CNT][ETH_GSTRING_LEN];
+extern const char stats_eth_phy_names[__ETHTOOL_A_STATS_ETH_PHY_CNT][ETH_GSTRING_LEN];
+
 #endif /* _NET_ETHTOOL_NETLINK_H */
diff --git a/net/ethtool/stats.c b/net/ethtool/stats.c
new file mode 100644
index 000000000000..fd8f47178c06
--- /dev/null
+++ b/net/ethtool/stats.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "netlink.h"
+#include "common.h"
+#include "bitset.h"
+
+struct stats_req_info {
+	struct ethnl_req_info		base;
+	DECLARE_BITMAP(stat_mask, __ETHTOOL_STATS_CNT);
+};
+
+#define STATS_REQINFO(__req_base) \
+	container_of(__req_base, struct stats_req_info, base)
+
+struct stats_reply_data {
+	struct ethnl_reply_data		base;
+	struct ethtool_eth_phy_stats	phy_stats;
+};
+
+#define STATS_REPDATA(__reply_base) \
+	container_of(__reply_base, struct stats_reply_data, base)
+
+const char stats_std_names[__ETHTOOL_STATS_CNT][ETH_GSTRING_LEN] = {
+	[ETHTOOL_STATS_ETH_PHY]			= "eth-phy",
+};
+
+const char stats_eth_phy_names[__ETHTOOL_A_STATS_ETH_PHY_CNT][ETH_GSTRING_LEN] = {
+	[ETHTOOL_A_STATS_ETH_PHY_5_SYM_ERR]	= "SymbolErrorDuringCarrier",
+};
+
+const struct nla_policy ethnl_stats_get_policy[ETHTOOL_A_STATS_GROUPS + 1] = {
+	[ETHTOOL_A_STATS_HEADER]	=
+		NLA_POLICY_NESTED(ethnl_header_policy),
+	[ETHTOOL_A_STATS_GROUPS]	= { .type = NLA_NESTED },
+};
+
+static int stats_parse_request(struct ethnl_req_info *req_base,
+			       struct nlattr **tb,
+			       struct netlink_ext_ack *extack)
+{
+	struct stats_req_info *req_info = STATS_REQINFO(req_base);
+	bool mod = false;
+	int err;
+
+	err = ethnl_update_bitset(req_info->stat_mask, __ETHTOOL_STATS_CNT,
+				  tb[ETHTOOL_A_STATS_GROUPS], stats_std_names,
+				  extack, &mod);
+	if (err)
+		return err;
+
+	if (!mod) {
+		NL_SET_ERR_MSG(extack, "no stats requested");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int stats_prepare_data(const struct ethnl_req_info *req_base,
+			      struct ethnl_reply_data *reply_base,
+			      struct genl_info *info)
+{
+	const struct stats_req_info *req_info = STATS_REQINFO(req_base);
+	struct stats_reply_data *data = STATS_REPDATA(reply_base);
+	struct net_device *dev = reply_base->dev;
+	int ret;
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		return ret;
+
+	memset(&data->phy_stats, 0xff, sizeof(data->phy_stats));
+
+	if (test_bit(ETHTOOL_STATS_ETH_PHY, req_info->stat_mask) &&
+	    dev->ethtool_ops->get_eth_phy_stats)
+		dev->ethtool_ops->get_eth_phy_stats(dev, &data->phy_stats);
+
+	ethnl_ops_complete(dev);
+	return 0;
+}
+
+static int stats_reply_size(const struct ethnl_req_info *req_base,
+			    const struct ethnl_reply_data *reply_base)
+{
+	const struct stats_req_info *req_info = STATS_REQINFO(req_base);
+	unsigned int n_grps = 0, n_stats = 0;
+	int len = 0;
+
+	if (test_bit(ETHTOOL_STATS_ETH_PHY, req_info->stat_mask)) {
+		n_stats += sizeof(struct ethtool_eth_phy_stats) / sizeof(u64);
+		n_grps++;
+	}
+
+	len += n_grps * (nla_total_size(0) + /* _A_STATS_GRP */
+			 nla_total_size(4) + /* _A_STATS_GRP_ID */
+			 nla_total_size(4)); /* _A_STATS_GRP_SS_ID */
+	len += n_stats * (nla_total_size(0) + /* _A_STATS_GRP_STAT */
+			  nla_total_size_64bit(sizeof(u64)));
+
+	return len;
+}
+
+static int stat_put(struct sk_buff *skb, u16 attrtype, u64 val)
+{
+	struct nlattr *nest;
+	int ret;
+
+	if (val == ETHTOOL_STAT_NOT_SET)
+		return 0;
+
+	/* We want to start stats attr types from 0, so we don't have a type
+	 * for pad inside ETHTOOL_A_STATS_GRP_STAT. Pad things on the outside
+	 * of ETHTOOL_A_STATS_GRP_STAT. Since we're one nest away from the
+	 * actual attr we're 4B off - nla_need_padding_for_64bit() & co.
+	 * can't be used.
+	 */
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (!IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
+		if (!nla_reserve(skb, ETHTOOL_A_STATS_GRP_PAD, 0))
+			return -EMSGSIZE;
+#endif
+
+	nest = nla_nest_start(skb, ETHTOOL_A_STATS_GRP_STAT);
+	if (!nest)
+		return -EMSGSIZE;
+
+	ret = nla_put_u64_64bit(skb, attrtype, val, -1 /* not used */);
+	if (ret) {
+		nla_nest_cancel(skb, nest);
+		return ret;
+	}
+
+	nla_nest_end(skb, nest);
+	return 0;
+}
+
+static int stats_put_phy_stats(struct sk_buff *skb,
+			       const struct stats_reply_data *data)
+{
+	if (stat_put(skb, ETHTOOL_A_STATS_ETH_PHY_5_SYM_ERR,
+		     data->phy_stats.SymbolErrorDuringCarrier))
+		return -EMSGSIZE;
+	return 0;
+}
+
+static int stats_put_stats(struct sk_buff *skb,
+			   const struct stats_reply_data *data,
+			   u32 id, u32 ss_id,
+			   int (*cb)(struct sk_buff *skb,
+				     const struct stats_reply_data *data))
+{
+	struct nlattr *nest;
+
+	nest = nla_nest_start(skb, ETHTOOL_A_STATS_GRP);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, ETHTOOL_A_STATS_GRP_ID, id) ||
+	    nla_put_u32(skb, ETHTOOL_A_STATS_GRP_SS_ID, ss_id))
+		goto err_cancel;
+
+	if (cb(skb, data))
+		goto err_cancel;
+
+	nla_nest_end(skb, nest);
+	return 0;
+
+err_cancel:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
+}
+
+static int stats_fill_reply(struct sk_buff *skb,
+			    const struct ethnl_req_info *req_base,
+			    const struct ethnl_reply_data *reply_base)
+{
+	const struct stats_req_info *req_info = STATS_REQINFO(req_base);
+	const struct stats_reply_data *data = STATS_REPDATA(reply_base);
+	int ret = 0;
+
+	if (!ret && test_bit(ETHTOOL_STATS_ETH_PHY, req_info->stat_mask))
+		ret = stats_put_stats(skb, data, ETHTOOL_STATS_ETH_PHY,
+				      ETH_SS_STATS_ETH_PHY,
+				      stats_put_phy_stats);
+
+	return ret;
+}
+
+const struct ethnl_request_ops ethnl_stats_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_STATS_GET,
+	.reply_cmd		= ETHTOOL_MSG_STATS_GET_REPLY,
+	.hdr_attr		= ETHTOOL_A_STATS_HEADER,
+	.req_info_size		= sizeof(struct stats_req_info),
+	.reply_data_size	= sizeof(struct stats_reply_data),
+
+	.parse_request		= stats_parse_request,
+	.prepare_data		= stats_prepare_data,
+	.reply_size		= stats_reply_size,
+	.fill_reply		= stats_fill_reply,
+};
diff --git a/net/ethtool/strset.c b/net/ethtool/strset.c
index c3a5489964cd..5f3c73587ff4 100644
--- a/net/ethtool/strset.c
+++ b/net/ethtool/strset.c
@@ -80,6 +80,16 @@ static const struct strset_info info_template[] = {
 		.count		= __ETHTOOL_UDP_TUNNEL_TYPE_CNT,
 		.strings	= udp_tunnel_type_names,
 	},
+	[ETH_SS_STATS_STD] = {
+		.per_dev	= false,
+		.count		= __ETHTOOL_STATS_CNT,
+		.strings	= stats_std_names,
+	},
+	[ETH_SS_STATS_ETH_PHY] = {
+		.per_dev	= false,
+		.count		= __ETHTOOL_A_STATS_ETH_PHY_CNT,
+		.strings	= stats_eth_phy_names,
+	},
 };
 
 struct strset_req_info {