ethtool: provide message mask with DEBUG_GET request

Implement DEBUG_GET request to get debugging settings for a device. At the
moment, only message mask corresponding to message level as reported by
ETHTOOL_GMSGLVL ioctl request is provided. (It is called message level in
ioctl interface but almost all drivers interpret it as a bit mask.)

As part of the implementation, provide symbolic names for message mask bits
as ETH_SS_MSG_CLASSES string set.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ethtool/Makefile

@@ -5,4 +5,4 @@ obj-y				+= ioctl.o common.o
 obj-$(CONFIG_ETHTOOL_NETLINK)	+= ethtool_nl.o
 
 ethtool_nl-y	:= netlink.o bitset.o strset.o linkinfo.o linkmodes.o \
-		   linkstate.o
+		   linkstate.o debug.o

net/ethtool/common.c

@@ -171,6 +171,25 @@ const char link_mode_names[][ETH_GSTRING_LEN] = {
 };
 static_assert(ARRAY_SIZE(link_mode_names) == __ETHTOOL_LINK_MODE_MASK_NBITS);
 
+const char netif_msg_class_names[][ETH_GSTRING_LEN] = {
+	[NETIF_MSG_DRV_BIT]		= "drv",
+	[NETIF_MSG_PROBE_BIT]		= "probe",
+	[NETIF_MSG_LINK_BIT]		= "link",
+	[NETIF_MSG_TIMER_BIT]		= "timer",
+	[NETIF_MSG_IFDOWN_BIT]		= "ifdown",
+	[NETIF_MSG_IFUP_BIT]		= "ifup",
+	[NETIF_MSG_RX_ERR_BIT]		= "rx_err",
+	[NETIF_MSG_TX_ERR_BIT]		= "tx_err",
+	[NETIF_MSG_TX_QUEUED_BIT]	= "tx_queued",
+	[NETIF_MSG_INTR_BIT]		= "intr",
+	[NETIF_MSG_TX_DONE_BIT]		= "tx_done",
+	[NETIF_MSG_RX_STATUS_BIT]	= "rx_status",
+	[NETIF_MSG_PKTDATA_BIT]		= "pktdata",
+	[NETIF_MSG_HW_BIT]		= "hw",
+	[NETIF_MSG_WOL_BIT]		= "wol",
+};
+static_assert(ARRAY_SIZE(netif_msg_class_names) == NETIF_MSG_CLASS_COUNT);
+
 /* return false if legacy contained non-0 deprecated fields
  * maxtxpkt/maxrxpkt. rest of ksettings always updated
  */

net/ethtool/common.h

@@ -19,6 +19,7 @@ tunable_strings[__ETHTOOL_TUNABLE_COUNT][ETH_GSTRING_LEN];
 extern const char
 phy_tunable_strings[__ETHTOOL_PHY_TUNABLE_COUNT][ETH_GSTRING_LEN];
 extern const char link_mode_names[][ETH_GSTRING_LEN];
+extern const char netif_msg_class_names[][ETH_GSTRING_LEN];
 
 int __ethtool_get_link(struct net_device *dev);
 

net/ethtool/debug.c

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "netlink.h"
+#include "common.h"
+#include "bitset.h"
+
+struct debug_req_info {
+	struct ethnl_req_info		base;
+};
+
+struct debug_reply_data {
+	struct ethnl_reply_data		base;
+	u32				msg_mask;
+};
+
+#define DEBUG_REPDATA(__reply_base) \
+	container_of(__reply_base, struct debug_reply_data, base)
+
+static const struct nla_policy
+debug_get_policy[ETHTOOL_A_DEBUG_MAX + 1] = {
+	[ETHTOOL_A_DEBUG_UNSPEC]	= { .type = NLA_REJECT },
+	[ETHTOOL_A_DEBUG_HEADER]	= { .type = NLA_NESTED },
+	[ETHTOOL_A_DEBUG_MSGMASK]	= { .type = NLA_REJECT },
+};
+
+static int debug_prepare_data(const struct ethnl_req_info *req_base,
+			      struct ethnl_reply_data *reply_base,
+			      struct genl_info *info)
+{
+	struct debug_reply_data *data = DEBUG_REPDATA(reply_base);
+	struct net_device *dev = reply_base->dev;
+	int ret;
+
+	if (!dev->ethtool_ops->get_msglevel)
+		return -EOPNOTSUPP;
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		return ret;
+	data->msg_mask = dev->ethtool_ops->get_msglevel(dev);
+	ethnl_ops_complete(dev);
+
+	return 0;
+}
+
+static int debug_reply_size(const struct ethnl_req_info *req_base,
+			    const struct ethnl_reply_data *reply_base)
+{
+	const struct debug_reply_data *data = DEBUG_REPDATA(reply_base);
+	bool compact = req_base->flags & ETHTOOL_FLAG_COMPACT_BITSETS;
+
+	return ethnl_bitset32_size(&data->msg_mask, NULL, NETIF_MSG_CLASS_COUNT,
+				   netif_msg_class_names, compact);
+}
+
+static int debug_fill_reply(struct sk_buff *skb,
+			    const struct ethnl_req_info *req_base,
+			    const struct ethnl_reply_data *reply_base)
+{
+	const struct debug_reply_data *data = DEBUG_REPDATA(reply_base);
+	bool compact = req_base->flags & ETHTOOL_FLAG_COMPACT_BITSETS;
+
+	return ethnl_put_bitset32(skb, ETHTOOL_A_DEBUG_MSGMASK, &data->msg_mask,
+				  NULL, NETIF_MSG_CLASS_COUNT,
+				  netif_msg_class_names, compact);
+}
+
+const struct ethnl_request_ops ethnl_debug_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_DEBUG_GET,
+	.reply_cmd		= ETHTOOL_MSG_DEBUG_GET_REPLY,
+	.hdr_attr		= ETHTOOL_A_DEBUG_HEADER,
+	.max_attr		= ETHTOOL_A_DEBUG_MAX,
+	.req_info_size		= sizeof(struct debug_req_info),
+	.reply_data_size	= sizeof(struct debug_reply_data),
+	.request_policy		= debug_get_policy,
+
+	.prepare_data		= debug_prepare_data,
+	.reply_size		= debug_reply_size,
+	.fill_reply		= debug_fill_reply,
+};

net/ethtool/netlink.c

@@ -213,6 +213,7 @@ ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
 	[ETHTOOL_MSG_LINKINFO_GET]	= &ethnl_linkinfo_request_ops,
 	[ETHTOOL_MSG_LINKMODES_GET]	= &ethnl_linkmodes_request_ops,
 	[ETHTOOL_MSG_LINKSTATE_GET]	= &ethnl_linkstate_request_ops,
+	[ETHTOOL_MSG_DEBUG_GET]		= &ethnl_debug_request_ops,
 };
 
 static struct ethnl_dump_ctx *ethnl_dump_context(struct netlink_callback *cb)
@@ -664,6 +665,13 @@ static const struct genl_ops ethtool_genl_ops[] = {
 		.dumpit	= ethnl_default_dumpit,
 		.done	= ethnl_default_done,
 	},
+	{
+		.cmd	= ETHTOOL_MSG_DEBUG_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[] = {

net/ethtool/netlink.h

@@ -334,6 +334,7 @@ extern const struct ethnl_request_ops ethnl_strset_request_ops;
 extern const struct ethnl_request_ops ethnl_linkinfo_request_ops;
 extern const struct ethnl_request_ops ethnl_linkmodes_request_ops;
 extern const struct ethnl_request_ops ethnl_linkstate_request_ops;
+extern const struct ethnl_request_ops ethnl_debug_request_ops;
 
 int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info);
 int ethnl_set_linkmodes(struct sk_buff *skb, struct genl_info *info);

net/ethtool/strset.c

@@ -50,6 +50,11 @@ static const struct strset_info info_template[] = {
 		.count		= __ETHTOOL_LINK_MODE_MASK_NBITS,
 		.strings	= link_mode_names,
 	},
+	[ETH_SS_MSG_CLASSES] = {
+		.per_dev	= false,
+		.count		= NETIF_MSG_CLASS_COUNT,
+		.strings	= netif_msg_class_names,
+	},
 };
 
 struct strset_req_info {