ethtool: add interface to read RMON stats

Most devices maintain RMON (RFC 2819) stats - particularly
the "histogram" of packets received by size. Unlike other
RFCs which duplicate IEEE stats, the short/oversized frame
counters in RMON don't seem to match IEEE stats 1-to-1 either,
so expose those, too. Do not expose basic packet, CRC errors
etc - those are already otherwise covered.

Because standard defines packet ranges only up to 1518, and
everything above that should theoretically be "oversized"
- devices often create their own ranges.

Going beyond what the RFC defines - expose the "histogram"
in the Tx direction (assume for now that the ranges will
be the same).

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

3 files changed, 93 insertions, 0 deletions

diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index febfa61e52e2..bed3afdf3656 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -405,5 +405,6 @@ 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];
 extern const char stats_eth_mac_names[__ETHTOOL_A_STATS_ETH_MAC_CNT][ETH_GSTRING_LEN];
 extern const char stats_eth_ctrl_names[__ETHTOOL_A_STATS_ETH_CTRL_CNT][ETH_GSTRING_LEN];
+extern const char stats_rmon_names[__ETHTOOL_A_STATS_RMON_CNT][ETH_GSTRING_LEN];
 
 #endif /* _NET_ETHTOOL_NETLINK_H */
diff --git a/net/ethtool/stats.c b/net/ethtool/stats.c
index f4fded66731c..acb2b080c358 100644
--- a/net/ethtool/stats.c
+++ b/net/ethtool/stats.c
@@ -17,6 +17,8 @@ struct stats_reply_data {
 	struct ethtool_eth_phy_stats	phy_stats;
 	struct ethtool_eth_mac_stats	mac_stats;
 	struct ethtool_eth_ctrl_stats	ctrl_stats;
+	struct ethtool_rmon_stats	rmon_stats;
+	const struct ethtool_rmon_hist_range	*rmon_ranges;
 };
 
 #define STATS_REPDATA(__reply_base) \
@@ -26,6 +28,7 @@ const char stats_std_names[__ETHTOOL_STATS_CNT][ETH_GSTRING_LEN] = {
 	[ETHTOOL_STATS_ETH_PHY]			= "eth-phy",
 	[ETHTOOL_STATS_ETH_MAC]			= "eth-mac",
 	[ETHTOOL_STATS_ETH_CTRL]		= "eth-ctrl",
+	[ETHTOOL_STATS_RMON]			= "rmon",
 };
 
 const char stats_eth_phy_names[__ETHTOOL_A_STATS_ETH_PHY_CNT][ETH_GSTRING_LEN] = {
@@ -63,6 +66,13 @@ const char stats_eth_ctrl_names[__ETHTOOL_A_STATS_ETH_CTRL_CNT][ETH_GSTRING_LEN]
 	[ETHTOOL_A_STATS_ETH_CTRL_5_RX_UNSUP]	= "UnsupportedOpcodesReceived",
 };
 
+const char stats_rmon_names[__ETHTOOL_A_STATS_RMON_CNT][ETH_GSTRING_LEN] = {
+	[ETHTOOL_A_STATS_RMON_UNDERSIZE]	= "etherStatsUndersizePkts",
+	[ETHTOOL_A_STATS_RMON_OVERSIZE]		= "etherStatsOversizePkts",
+	[ETHTOOL_A_STATS_RMON_FRAG]		= "etherStatsFragments",
+	[ETHTOOL_A_STATS_RMON_JABBER]		= "etherStatsJabbers",
+};
+
 const struct nla_policy ethnl_stats_get_policy[ETHTOOL_A_STATS_GROUPS + 1] = {
 	[ETHTOOL_A_STATS_HEADER]	=
 		NLA_POLICY_NESTED(ethnl_header_policy),
@@ -107,6 +117,7 @@ static int stats_prepare_data(const struct ethnl_req_info *req_base,
 	memset(&data->phy_stats, 0xff, sizeof(data->phy_stats));
 	memset(&data->mac_stats, 0xff, sizeof(data->mac_stats));
 	memset(&data->ctrl_stats, 0xff, sizeof(data->mac_stats));
+	memset(&data->rmon_stats, 0xff, sizeof(data->rmon_stats));
 
 	if (test_bit(ETHTOOL_STATS_ETH_PHY, req_info->stat_mask) &&
 	    dev->ethtool_ops->get_eth_phy_stats)
@@ -117,6 +128,10 @@ static int stats_prepare_data(const struct ethnl_req_info *req_base,
 	if (test_bit(ETHTOOL_STATS_ETH_CTRL, req_info->stat_mask) &&
 	    dev->ethtool_ops->get_eth_ctrl_stats)
 		dev->ethtool_ops->get_eth_ctrl_stats(dev, &data->ctrl_stats);
+	if (test_bit(ETHTOOL_STATS_RMON, req_info->stat_mask) &&
+	    dev->ethtool_ops->get_rmon_stats)
+		dev->ethtool_ops->get_rmon_stats(dev, &data->rmon_stats,
+						 &data->rmon_ranges);
 
 	ethnl_ops_complete(dev);
 	return 0;
@@ -141,6 +156,16 @@ static int stats_reply_size(const struct ethnl_req_info *req_base,
 		n_stats += sizeof(struct ethtool_eth_ctrl_stats) / sizeof(u64);
 		n_grps++;
 	}
+	if (test_bit(ETHTOOL_STATS_RMON, req_info->stat_mask)) {
+		n_stats += sizeof(struct ethtool_rmon_stats) / sizeof(u64);
+		n_grps++;
+		/* Above includes the space for _A_STATS_GRP_HIST_VALs */
+
+		len += (nla_total_size(0) +	/* _A_STATS_GRP_HIST */
+			nla_total_size(4) +	/* _A_STATS_GRP_HIST_BKT_LOW */
+			nla_total_size(4)) *	/* _A_STATS_GRP_HIST_BKT_HI */
+			ETHTOOL_RMON_HIST_MAX * 2;
+	}
 
 	len += n_grps * (nla_total_size(0) + /* _A_STATS_GRP */
 			 nla_total_size(4) + /* _A_STATS_GRP_ID */
@@ -258,6 +283,65 @@ static int stats_put_ctrl_stats(struct sk_buff *skb,
 	return 0;
 }
 
+static int stats_put_rmon_hist(struct sk_buff *skb, u32 attr, const u64 *hist,
+			       const struct ethtool_rmon_hist_range *ranges)
+{
+	struct nlattr *nest;
+	int i;
+
+	if (!ranges)
+		return 0;
+
+	for (i = 0; i <	ETHTOOL_RMON_HIST_MAX; i++) {
+		if (!ranges[i].low && !ranges[i].high)
+			break;
+		if (hist[i] == ETHTOOL_STAT_NOT_SET)
+			continue;
+
+		nest = nla_nest_start(skb, attr);
+		if (!nest)
+			return -EMSGSIZE;
+
+		if (nla_put_u32(skb, ETHTOOL_A_STATS_GRP_HIST_BKT_LOW,
+				ranges[i].low) ||
+		    nla_put_u32(skb, ETHTOOL_A_STATS_GRP_HIST_BKT_HI,
+				ranges[i].high) ||
+		    nla_put_u64_64bit(skb, ETHTOOL_A_STATS_GRP_HIST_VAL,
+				      hist[i], ETHTOOL_A_STATS_GRP_PAD))
+			goto err_cancel_hist;
+
+		nla_nest_end(skb, nest);
+	}
+
+	return 0;
+
+err_cancel_hist:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
+}
+
+static int stats_put_rmon_stats(struct sk_buff *skb,
+				const struct stats_reply_data *data)
+{
+	if (stats_put_rmon_hist(skb, ETHTOOL_A_STATS_GRP_HIST_RX,
+				data->rmon_stats.hist, data->rmon_ranges) ||
+	    stats_put_rmon_hist(skb, ETHTOOL_A_STATS_GRP_HIST_TX,
+				data->rmon_stats.hist_tx, data->rmon_ranges))
+		return -EMSGSIZE;
+
+	if (stat_put(skb, ETHTOOL_A_STATS_RMON_UNDERSIZE,
+		     data->rmon_stats.undersize_pkts) ||
+	    stat_put(skb, ETHTOOL_A_STATS_RMON_OVERSIZE,
+		     data->rmon_stats.oversize_pkts) ||
+	    stat_put(skb, ETHTOOL_A_STATS_RMON_FRAG,
+		     data->rmon_stats.fragments) ||
+	    stat_put(skb, ETHTOOL_A_STATS_RMON_JABBER,
+		     data->rmon_stats.jabbers))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
 static int stats_put_stats(struct sk_buff *skb,
 			   const struct stats_reply_data *data,
 			   u32 id, u32 ss_id,
@@ -305,6 +389,9 @@ static int stats_fill_reply(struct sk_buff *skb,
 		ret = stats_put_stats(skb, data, ETHTOOL_STATS_ETH_CTRL,
 				      ETH_SS_STATS_ETH_CTRL,
 				      stats_put_ctrl_stats);
+	if (!ret && test_bit(ETHTOOL_STATS_RMON, req_info->stat_mask))
+		ret = stats_put_stats(skb, data, ETHTOOL_STATS_RMON,
+				      ETH_SS_STATS_RMON, stats_put_rmon_stats);
 
 	return ret;
 }
diff --git a/net/ethtool/strset.c b/net/ethtool/strset.c
index a33c603a7a02..b3029fff715d 100644
--- a/net/ethtool/strset.c
+++ b/net/ethtool/strset.c
@@ -100,6 +100,11 @@ static const struct strset_info info_template[] = {
 		.count		= __ETHTOOL_A_STATS_ETH_CTRL_CNT,
 		.strings	= stats_eth_ctrl_names,
 	},
+	[ETH_SS_STATS_RMON] = {
+		.per_dev	= false,
+		.count		= __ETHTOOL_A_STATS_RMON_CNT,
+		.strings	= stats_rmon_names,
+	},
 };
 
 struct strset_req_info {