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>

1 files changed, 43 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 1ca6b836f9fe..e030f7510cd3 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -346,6 +346,44 @@ struct ethtool_fec_stats {
 	} corrected_blocks, uncorrectable_blocks, corrected_bits;
 };
 
+/**
+ * struct ethtool_rmon_hist_range - byte range for histogram statistics
+ * @low: low bound of the bucket (inclusive)
+ * @high: high bound of the bucket (inclusive)
+ */
+struct ethtool_rmon_hist_range {
+	u16 low;
+	u16 high;
+};
+
+#define ETHTOOL_RMON_HIST_MAX	10
+
+/**
+ * struct ethtool_rmon_stats - selected RMON (RFC 2819) statistics
+ * @undersize_pkts: Equivalent to `etherStatsUndersizePkts` from the RFC.
+ * @oversize_pkts: Equivalent to `etherStatsOversizePkts` from the RFC.
+ * @fragments: Equivalent to `etherStatsFragments` from the RFC.
+ * @jabbers: Equivalent to `etherStatsJabbers` from the RFC.
+ * @hist: Packet counter for packet length buckets (e.g.
+ *	`etherStatsPkts128to255Octets` from the RFC).
+ * @hist_tx: Tx counters in similar form to @hist, not defined in the RFC.
+ *
+ * Selection of RMON (RFC 2819) statistics which are not exposed via different
+ * APIs, primarily the packet-length-based counters.
+ * Unfortunately different designs choose different buckets beyond
+ * the 1024B mark (jumbo frame teritory), so the definition of the bucket
+ * ranges is left to the driver.
+ */
+struct ethtool_rmon_stats {
+	u64 undersize_pkts;
+	u64 oversize_pkts;
+	u64 fragments;
+	u64 jabbers;
+
+	u64 hist[ETHTOOL_RMON_HIST_MAX];
+	u64 hist_tx[ETHTOOL_RMON_HIST_MAX];
+};
+
 #define ETH_MODULE_EEPROM_PAGE_LEN	128
 #define ETH_MODULE_MAX_I2C_ADDRESS	0x7f
 
@@ -534,6 +572,8 @@ struct ethtool_module_eeprom {
  * @get_eth_phy_stats: Query some of the IEEE 802.3 PHY statistics.
  * @get_eth_mac_stats: Query some of the IEEE 802.3 MAC statistics.
  * @get_eth_ctrl_stats: Query some of the IEEE 802.3 MAC Ctrl statistics.
+ * @get_rmon_stats: Query some of the RMON (RFC 2819) statistics.
+ *	Set %ranges to a pointer to zero-terminated array of byte ranges.
  *
  * All operations are optional (i.e. the function pointer may be set
  * to %NULL) and callers must take this into account.  Callers must
@@ -650,6 +690,9 @@ struct ethtool_ops {
 				     struct ethtool_eth_mac_stats *mac_stats);
 	void	(*get_eth_ctrl_stats)(struct net_device *dev,
 				      struct ethtool_eth_ctrl_stats *ctrl_stats);
+	void	(*get_rmon_stats)(struct net_device *dev,
+				  struct ethtool_rmon_stats *rmon_stats,
+				  const struct ethtool_rmon_hist_range **ranges);
 };
 
 int ethtool_check_ops(const struct ethtool_ops *ops);