Net: Ethernet: differentiate ethernet from wifi if

include/zephyr/net/ethernet.h

@@ -1412,6 +1412,20 @@ static inline bool net_eth_type_is_wifi(struct net_if *iface)
 	return ctx->eth_if_type == L2_ETH_IF_TYPE_WIFI;
 }
 
+/**
+ * @brief Check if the Ethernet L2 network interface is cabled ethernet.
+ *
+ * @param iface Pointer to network interface
+ *
+ * @return True if interface is cabled ethernet, False otherwise.
+ */
+static inline bool net_eth_type_is_ethernet(struct net_if *iface)
+{
+	const struct ethernet_context *ctx = (struct ethernet_context *)net_if_l2_data(iface);
+
+	return ctx->eth_if_type == L2_ETH_IF_TYPE_ETHERNET;
+}
+
 /**
  * @}
  */

include/zephyr/net/net_if.h

@@ -3327,6 +3327,22 @@ int net_if_resume(struct net_if *iface);
 bool net_if_is_suspended(struct net_if *iface);
 #endif /* CONFIG_NET_POWER_MANAGEMENT */
 
+/**
+ * @brief Check if the network interface is cabled ethernet
+ *
+ * @param iface Pointer to network interface
+ *
+ * @return True if interface is cabled ethernet, False otherwise.
+ */
+bool net_if_is_ethernet(struct net_if *iface);
+
+/**
+ * @brief Get first Cabled Ethernet network interface.
+ *
+ * @return Pointer to network interface, NULL if not found.
+ */
+struct net_if *net_if_get_first_ethernet(void);
+
 /**
  * @brief Check if the network interface supports Wi-Fi.
  *

subsys/net/ip/net_if.c

@@ -622,7 +622,7 @@ struct net_if *net_if_get_default(void)
 	}
 
 #if defined(CONFIG_NET_DEFAULT_IF_ETHERNET)
-	iface = net_if_get_first_by_type(&NET_L2_GET_NAME(ETHERNET));
+	iface = net_if_get_first_ethernet();
 #endif
 #if defined(CONFIG_NET_DEFAULT_IF_IEEE802154)
 	iface = net_if_get_first_by_type(&NET_L2_GET_NAME(IEEE802154));
@@ -6239,6 +6239,26 @@ void net_if_add_tx_timestamp(struct net_pkt *pkt)
 }
 #endif /* CONFIG_NET_PKT_TIMESTAMP_THREAD */
 
+bool net_if_is_ethernet(struct net_if *iface)
+{
+	if (IS_ENABLED(CONFIG_NET_L2_ETHERNET)) {
+		return net_if_l2(iface) == &NET_L2_GET_NAME(ETHERNET) &&
+		       net_eth_type_is_ethernet(iface);
+	}
+
+	return false;
+}
+
+struct net_if *net_if_get_first_ethernet(void)
+{
+	STRUCT_SECTION_FOREACH(net_if, iface) {
+		if (net_if_is_ethernet(iface)) {
+			return iface;
+		}
+	}
+	return NULL;
+}
+
 bool net_if_is_wifi(struct net_if *iface)
 {
 	if (net_if_is_offloaded(iface)) {