base-files: rename ethernet devs on known boards

Some platforms lack an established way to name netdevs; for example,
on x86, PCIe-based ethernet interfaces will be named starting from
eth0 in the order they are probed. This is a problem for many devices
supported explicitly by OpenWrt which have hard-wired, standalone or
on-CPU NICs not supported by DSA (which is usually used to rename the
ports based on their ostensible function).

To fix this, add a mapping between ethernet device name and sysfs
device path to board.json; this allows us to configure ethernet device
names we know about for a given board so that they correspond to
external labeling.

Signed-off-by: Martin Kennedy <[email protected]>

package/base-files/files/lib/functions/uci-defaults.sh

@@ -114,6 +114,14 @@ ucidef_set_network_device_mac() {
 	json_select ..
 }
 
+ucidef_set_network_device_path() {
+	json_select_object "network_device"
+	json_select_object "$1"
+	json_add_string path "$2"
+	json_select ..
+	json_select ..
+}
+
 _ucidef_add_switch_port() {
 	# inherited: $num $device $need_tag $want_untag $role $index $prev_role
 	# inherited: $n_cpu $n_ports $n_vlan $cpu0 $cpu1 $cpu2 $cpu3 $cpu4 $cpu5

package/base-files/files/lib/preinit/10_indicate_preinit

@@ -63,6 +63,20 @@ preinit_config_switch() {
 	json_select ..
 }
 
+preinit_config_port() {
+	local original
+
+	local netdev="$1"
+	local path="$2"
+
+	[ -d "/sys/devices/$path/net" ] || return
+	original="$(ls "/sys/devices/$path/net" | head -1)"
+
+	[ "$netdev" = "$original" ] && return
+
+	ip link set "$original" name "$netdev"
+}
+
 preinit_config_board() {
 	/bin/board_detect /tmp/board.json
 
@@ -73,6 +87,35 @@ preinit_config_board() {
 	json_init
 	json_load "$(cat /tmp/board.json)"
 
+	# Find the current highest eth*
+	max_eth=$(grep -o '^ *eth[0-9]*:' /proc/net/dev | tr -dc '[0-9]\n' | sort -n | tail -1)
+	# Find and move netdevs using eth*s we are configuring
+	json_get_keys keys "network_device"
+	for netdev in $keys; do
+		json_select "network_device"
+			json_select "$netdev"
+				json_get_vars path path
+				next_eth="$(echo "$netdev" | grep 'eth[0-9]*' | tr -dc '[0-9]')"
+				[ "$next_eth" -gt "$max_eth" ] && max_eth=$next_eth
+				if [ -n "$path" -a -h "/sys/class/net/$netdev" ]; then
+					ip link set "$netdev" down
+					ip link set "$netdev" name eth$((++max_eth))
+				fi
+			json_select ..
+		json_select ..
+	done
+
+	# Move interfaces by path to their netdev name
+	json_get_keys keys "network_device"
+	for netdev in $keys; do
+		json_select "network_device"
+			json_select "$netdev"
+				json_get_vars path path
+				[ -n "$path" ] && preinit_config_port "$netdev" "$path"
+			json_select ..
+		json_select ..
+	done
+
 	json_select network
 		json_select "lan"
 			json_get_vars device