[PATCH net-next 12/13] netlink: specs: Add ethernet port listing with ethtool

Maxime Chevallier
2026-01-27T13:42:50Z

Ethernet network interfaces may have more than one front-facing port.
The phy_port infrastructure was introduced to keep track of
these ports, and allow userspace to know about the presence and
capability of these ports. Add a ethnl netlink message to report this
information.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
Documentation/netlink/specs/ethtool.yaml | 50 +++++++++++++++++++
Documentation/networking/ethtool-netlink.rst | 35 +++++++++++++
.../uapi/linux/ethtool_netlink_generated.h | 19 +++++++
3 files changed, 104 insertions(+)

diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml
index 0a2d2343f79a..f0f424009fb0 100644
--- a/Documentation/netlink/specs/ethtool.yaml
+++ b/Documentation/netlink/specs/ethtool.yaml
@@ -210,6 +210,10 @@ definitions:
-
name: discard
value: 31
+ -
+ name: port-type
+ type: enum
+ entries: [mdi, sfp]

attribute-sets:
-
@@ -1890,6 +1894,32 @@ attribute-sets:
name: link
type: nest
nested-attributes: mse-snapshot
+ -
+ name: port
+ attr-cnt-name: --ethtool-a-port-cnt
+ attributes:
+ -
+ name: header
+ type: nest
+ nested-attributes: header
+ -
+ name: id
+ type: u32
+ -
+ name: supported-modes
+ type: nest
+ nested-attributes: bitset
+ -
+ name: supported-interfaces
+ type: nest
+ nested-attributes: bitset
+ -
+ name: type
+ type: u8
+ enum: port-type
+ -
+ name: occupied
+ type: u8

operations:
enum-model: directional
@@ -2842,6 +2872,26 @@ operations:
- worst-channel
- link
dump: *mse-get-op
+ -
+ name: port-get
+ doc: Get ports attached to an interface
+
+ attribute-set: port
+
+ do: &port-get-op
+ request:
+ attributes:
+ - header
+ - id
+ reply:
+ attributes:
+ - header
+ - id
+ - supported-modes
+ - supported-interfaces
+ - type
+ - occupied
+ dump: *port-get-op

mcast-groups:
list:
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index af56c304cef4..450004d545b8 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -2522,6 +2522,40 @@ Within each channel nest, only the metrics supported by the PHY will be present.
See ``struct phy_mse_snapshot`` kernel documentation in
``include/linux/phy.h``.

+PORT_GET
+========
+
+Retrieve information about the physical connection points of a network device,
+referred to as "ports". User needs to specify a PORT_ID for the DO operation,
+in which case the DO request returns information about that specific port.
+
+As there can be more than one port, the DUMP operation can be used to list the
+ports present on a given interface, by passing an interface index or name in
+the dump request.
+
+Request contents:
+
+==================================== ====== =================================
+ ``ETHTOOL_A_PORT_HEADER`` nested request header
+ ``ETHTOOL_A_PORT_ID`` u32 port id
+ ==================================== ====== ===============================
+
+Kernel response contents:
+
+ ===================================== ====== =============================
+ ``ETHTOOL_A_PORT_HEADER`` nested request header
+ ``ETHTOOL_A_PORT_ID`` u32 the port's unique identifier,
+ per netdevice.
+ ``ETHTOOL_A_PORT_SUPPORTED_MODES`` bitset bitset of supported linkmodes
+ ``ETHTOOL_A_PORT_SUPPORTED_INTERFACES`` bitset bitset of supported MII
+ interfaces
+ ``ETHTOOL_A_PORT_TYPE`` u32 the port type
+ ``ETHTOOL_A_PORT_OCCUPIED`` u8 for non-mdi ports, indicates
+ if the port is connected
+ another device that could
+ expose a MDI
+ ===================================== ====== =============================
+
Request translation
===================

@@ -2632,4 +2666,5 @@ are netlink only.
n/a ``ETHTOOL_MSG_PHY_GET``
``SIOCGHWTSTAMP`` ``ETHTOOL_MSG_TSCONFIG_GET``
``SIOCSHWTSTAMP`` ``ETHTOOL_MSG_TSCONFIG_SET``
+ n/a ``ETHTOOL_MSG_PORT_GET``
=================================== =====================================
diff --git a/include/uapi/linux/ethtool_netlink_generated.h b/include/uapi/linux/ethtool_netlink_generated.h
index 556a0c834df5..7ccd864a6e38 100644
--- a/include/uapi/linux/ethtool_netlink_generated.h
+++ b/include/uapi/linux/ethtool_netlink_generated.h
@@ -78,6 +78,11 @@ enum ethtool_pse_event {
ETHTOOL_PSE_EVENT_SW_PW_CONTROL_ERROR = 64,
};

+enum ethtool_port_type {
+ ETHTOOL_PORT_TYPE_MDI,
+ ETHTOOL_PORT_TYPE_SFP,
+};
+
enum {
ETHTOOL_A_HEADER_UNSPEC,
ETHTOOL_A_HEADER_DEV_INDEX,
@@ -837,6 +842,18 @@ enum {
ETHTOOL_A_MSE_MAX = (__ETHTOOL_A_MSE_CNT - 1)
};

+enum {
+ ETHTOOL_A_PORT_HEADER = 1,
+ ETHTOOL_A_PORT_ID,
+ ETHTOOL_A_PORT_SUPPORTED_MODES,
+ ETHTOOL_A_PORT_SUPPORTED_INTERFACES,
+ ETHTOOL_A_PORT_TYPE,
+ ETHTOOL_A_PORT_OCCUPIED,
+
+ __ETHTOOL_A_PORT_CNT,
+ ETHTOOL_A_PORT_MAX = (__ETHTOOL_A_PORT_CNT - 1)
+};
+
enum {
ETHTOOL_MSG_USER_NONE = 0,
ETHTOOL_MSG_STRSET_GET = 1,
@@ -890,6 +907,7 @@ enum {
ETHTOOL_MSG_RSS_CREATE_ACT,
ETHTOOL_MSG_RSS_DELETE_ACT,
ETHTOOL_MSG_MSE_GET,
+ ETHTOOL_MSG_PORT_GET,

__ETHTOOL_MSG_USER_CNT,
ETHTOOL_MSG_USER_MAX = (__ETHTOOL_MSG_USER_CNT - 1)
@@ -951,6 +969,7 @@ enum {
ETHTOOL_MSG_RSS_CREATE_NTF,
ETHTOOL_MSG_RSS_DELETE_NTF,
ETHTOOL_MSG_MSE_GET_REPLY,
+ ETHTOOL_MSG_PORT_GET_REPLY,

__ETHTOOL_MSG_KERNEL_CNT,
ETHTOOL_MSG_KERNEL_MAX = (__ETHTOOL_MSG_KERNEL_CNT - 1)
--
2.49.0