[PATCH net-next v5 2/3] ethtool: add a PHY receive byte total

[James Hilliard <james.hilliard1@gmail.com>]

The generic PHY receive-byte counter describes successfully received
traffic. Some PHYs instead count bytes in all received frames, including
frames with errors. Unlike frame counts, the successful-byte count cannot
be derived by subtracting a frame error count because damaged frames have
different lengths.

Add an optional rx_bytes_total counter to ethtool_phy_stats and the phydev
statistics group. Count frame bytes including the Ethernet header, padding
and FCS, and excluding the preamble and start frame delimiter. The counter
describes reception at the PHY, before MAC or host filtering. Clarify the
same byte boundaries for the successful-only receive counter.

Append the new attribute so existing statistic IDs and their meanings
remain unchanged. Publish its name through the existing statistics string
set and retain the unset-counter convention.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
 Documentation/networking/ethtool-netlink.rst | 13 +++++++++++++
 include/linux/ethtool.h                      |  8 +++++++-
 include/uapi/linux/ethtool_netlink.h         |  1 +
 net/ethtool/stats.c                          |  5 ++++-
 4 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 8659761ebc69..1dad86561823 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -1683,6 +1683,19 @@ by ``ETHTOOL_A_STATS_GRP_SS_ID``. Complex statistics (such as RMON histogram
 entries) are also listed inside ``ETHTOOL_A_STATS_GRP`` and do not have
 a string defined in the string set.
 
+The ``phydev`` group provides separate counters for successfully received
+bytes and total received bytes. ``ETHTOOL_A_STATS_PHY_RX_BYTES`` (``RxOctets``)
+counts bytes in successfully received frames, while
+``ETHTOOL_A_STATS_PHY_RX_BYTES_TOTAL`` (``RxOctetsTotal``) also includes bytes
+in frames with errors. Both include the Ethernet header, padding and FCS,
+but exclude the preamble and start frame delimiter. These counters describe
+reception at the PHY, independently of subsequent filtering or drops at
+the MAC or host.
+
+Each counter is optional. Drivers leave unsupported counters at
+``ETHTOOL_STAT_NOT_SET``, and the kernel omits them from the reply. A PHY can
+report total received bytes even when it cannot separate successful bytes.
+
 RMON "histogram" counters count number of packets within given size range.
 Because RFC does not specify the ranges beyond the standard 1518 MTU devices
 differ in definition of buckets. For this reason the definition of packet ranges
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index c3a41fbd5426..fedc127d9a8a 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -481,11 +481,16 @@ struct ethtool_eth_phy_stats {
 /**
  * struct ethtool_phy_stats - PHY-level statistics counters
  * @rx_packets: Total successfully received frames
- * @rx_bytes: Total successfully received bytes
+ * @rx_bytes: Total successfully received frame bytes. Includes the Ethernet
+ *	header, padding and FCS, but excludes the preamble and start frame
+ *	delimiter.
  * @rx_errors: Total received frames with errors (e.g., CRC errors)
  * @tx_packets: Total successfully transmitted frames
  * @tx_bytes: Total successfully transmitted bytes
  * @tx_errors: Total transmitted frames with errors
+ * @rx_bytes_total: Total received frame bytes, including frames with errors.
+ *	Includes the Ethernet header, padding and FCS, but excludes the preamble
+ *	and start frame delimiter.
  *
  * This structure provides a standardized interface for reporting
  * PHY-level statistics counters. It is designed to expose statistics
@@ -499,6 +504,7 @@ struct ethtool_phy_stats {
 	u64 tx_packets;
 	u64 tx_bytes;
 	u64 tx_errors;
+	u64 rx_bytes_total;
 };
 
 /* Basic IEEE 802.3 MAC Ctrl statistics (30.3.3.*), not otherwise exposed
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index fa5d645140a4..2e81f7345f72 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -202,6 +202,7 @@ enum {
 	ETHTOOL_A_STATS_PHY_TX_PKTS,
 	ETHTOOL_A_STATS_PHY_TX_BYTES,
 	ETHTOOL_A_STATS_PHY_TX_ERRORS,
+	ETHTOOL_A_STATS_PHY_RX_BYTES_TOTAL,
 
 	/* add new constants above here */
 	__ETHTOOL_A_STATS_PHY_CNT,
diff --git a/net/ethtool/stats.c b/net/ethtool/stats.c
index 9b0d8cb07675..9b9ada615ac2 100644
--- a/net/ethtool/stats.c
+++ b/net/ethtool/stats.c
@@ -88,6 +88,7 @@ const char stats_phy_names[__ETHTOOL_A_STATS_PHY_CNT][ETH_GSTRING_LEN] = {
 	[ETHTOOL_A_STATS_PHY_TX_PKTS]		= "TxFrames",
 	[ETHTOOL_A_STATS_PHY_TX_BYTES]		= "TxOctets",
 	[ETHTOOL_A_STATS_PHY_TX_ERRORS]		= "TxErrors",
+	[ETHTOOL_A_STATS_PHY_RX_BYTES_TOTAL]	= "RxOctetsTotal",
 };
 
 const struct nla_policy ethnl_stats_get_policy[ETHTOOL_A_STATS_SRC + 1] = {
@@ -295,7 +296,9 @@ static int stats_put_phydev_stats(struct sk_buff *skb,
 	    stat_put(skb, ETHTOOL_A_STATS_PHY_TX_BYTES,
 		     data->phydev_stats.tx_bytes) ||
 	    stat_put(skb, ETHTOOL_A_STATS_PHY_TX_ERRORS,
-		     data->phydev_stats.tx_errors))
+		     data->phydev_stats.tx_errors) ||
+	    stat_put(skb, ETHTOOL_A_STATS_PHY_RX_BYTES_TOTAL,
+		     data->phydev_stats.rx_bytes_total))
 		return -EMSGSIZE;
 	return 0;
 }

-- 
2.53.0