How does OpenWrt ensure network device names are consistent?

Installing and Using OpenWrt
6

afaik interfaces are switched around depending on the order in which they appear (and on boot also the order the drivers are loaded does determine how things are named).

I had developed a script that re-assignes interfaces by reading the mac address, and use it as a local package in my builds (it's installed and run as a service on boot) as my usecase was mainly to ship a pre-written config file so that if I decide to erase the config on sysupgrade it does not reset interfaces and Lan becomes whatever and I need to go and swap cables and manually change it back.

but you probably need to add it to hotplug folder as well so it's triggered every time a new network device is added/removed

This is the procd init script

#!/bin/sh /etc/rc.common

START=11

# don't run within buildroot
[ -n "${IPKG_INSTROOT}" ] && return 0

#use busybox grep as GNU grep may be set differently and break the script
grep(){
/bin/busybox 'grep' $@
}

#shutting down all interfaces, then assigning temporary name to free up interface names
#bridges and virtual interfaces are already excluded by  /sys/class/net/*/device/uevent as only physical interfaces have that
for i in $( ls /sys/class/net/*/device/uevent | awk -F'/' '{print $5}' | tr '\n' ' ' ) ;
do

	mac_address=$( grep $i /etc/config/mac-static-interfaces | awk '{print $3}' | tr -d '"' )
	if [ "$mac_address" != '' ]; then
	
		ip link set "$i" down 
		ip link set "$i" name old"$i"
		
	fi
done

for i in $( ls /sys/class/net/*/device/uevent | awk -F'/' '{print $5}' | tr '\n' ' ' ) ;
do

mac_address=$( cat /sys/class/net/$i/address  )
	interface_name=$( grep -i $mac_address /etc/config/mac-static-interfaces | awk '{print $2}' )
	if [ "$interface_name" != '' ]; then
	
		ip link set "$i" down 
		ip link set "$i" name "$interface_name"
		
	fi
done

and this is the config file /etc/config/mac-static-interfaces


config mac-static-interfaces
	#option eth0 "70:85:c2:8a:57:4d"
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