show: add support for port classification and "show port NAME"

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

board/common/rootfs/bin/show

@@ -1,5 +1,6 @@
 #!/bin/sh
 # Displays basic information about the system
+# shellcheck disable=SC2048,SC2086
 . /etc/os-release
 
 opt="-br"
@@ -20,6 +21,7 @@ options:
   -h            Show this help text
 
 commands:
+  port PORT     Show port configuration and link information
   ports         Show ports available for bridging
   vlans         Show port groups in bridge
   ifaces        Show interfaces and their addresses
@@ -33,8 +35,53 @@ commands:
 EOF
 }
 
+# Update port classification, new ports may have been probed
+update_port_group()
+{
+	if ! grep -q port /etc/iproute2/group; then
+		mkdir -p /etc/iproute2
+		echo "1	port" >> /etc/iproute2/group
+	fi
+
+	# Clear port group
+	ifaces=$(command ip -br link | awk '{print $1}' | sed 's/@.*//g')
+	for iface in $ifaces; do
+		ip link set "$iface" group default
+	done
+
+	ports=$(devlink port 2>/dev/null | awk '/flavour physical/{print $5}')
+	for iface in $ports; do
+		ip link set "$iface" group port
+	done
+
+	# Fallback: check if user has configured any bridge ports
+	if [ -z "$ports" ]; then
+		for iface in $ifaces; do
+			if [ -d "/sys/class/net/$iface/brport" ]; then
+				ip link set "$iface" group port
+			fi
+		done
+	fi
+}
+
+# Usage 1: show port eth0
+# Usage 2: show port
+# Usage 3: show ports
+#
+# The first show ethtool output for 'eth0' (in this case).  The latter
+# two are the same, showing a summary of all interfaces classified as
+# access ports.
 ports()
 {
+	if [ $# -gt 0 ] && [ -e "/sys/class/net/$1" ]; then
+		for port in $*; do
+			ethtool "$port"
+		done
+		return
+	fi
+
+	update_port_group
+
 	printf "\e[7mPORT             STATE          ADDRESS <FLAGS>                               \e[0m\n"
 	if grep -q port /etc/iproute2/group && [ -z "$all" ]; then
 		ip $opt link show group port
@@ -167,7 +214,7 @@ case $cmd in
 		usage
 		;;
 	port*)
-		ports
+		ports $*
 		;;
 	vlan*)
 		vlans
@@ -192,7 +239,7 @@ case $cmd in
 				routes
 				;;
 			igmp*)
-				igmp "$*"
+				igmp $*
 				;;
 			*)
 				usage
@@ -200,10 +247,10 @@ case $cmd in
 		esac
 		;;
 	log)
-		log "$1"
+		log $1
 		;;
 	rmon)
-		rmon "$*"
+		rmon $*
 		;;
 	route*)
 		routes