Generally, using /jffs/scripts/dnsmasq.postconf is the right way to add
custom configuration to dnsmasq on Merlin. However, we have seen many
reports that the postconf does not work on their devices.
This commit changes how dnsmasq config manipulation is done on Merlin,
so it's expected to work on all Merlin devices:
- Writing /jffs/scripts/dnsmasq.postconf script
- Copy current dnsmasq.conf to /jffs/configs/dnsmasq.conf
- Run postconf script directly on /jffs/configs/dnsmasq.conf
- Restart dnsmasq
This way, the /jffs/configs/dnsmasq.conf will contain both current
dnsmasq config, and also custom config added by ctrld, without worrying
about conflicting, because configuration was added by postconf.
See (1) for more details about custom config files on Merlin.
(1) https://github.com/RMerl/asuswrt-merlin.ng/wiki/Custom-config-files
The postconf script added by ctrld requires all of these conditions to
work correctly:
- /proc, /tmp were mounted.
- dnsmasq is running.
Currently, ctrld is only waiting for NTP ready, which may not ensure
both of those conditions are true. Explicitly checking those conditions
is a safer approach.
On routers where we want to wait for NTP by checking nvram key. Before
waiting, we clean up the router to ensure it's restored to original
state. However, router.Cleanup is not idempotent, causing dnsmasq
restarted. On tomato/ddwrt, restarting have no delay, and spawning new
dnsmasq process immediately. On merlin, somehow it takes time to spawn
new dnsmasq process, causing ctrld wrongly think there's no one
listening on port 53.
Fixing this by ensuring router.Cleanup is idempotent. While at it, also
adding "ntp_done" to nvram key, which is now using on latest ddwrt.
Config fetching/generating in cd mode is currently weird, error prone,
and easy for user to break ctrld when using custom config.
This commit reworks the flow:
- Fetching config from Control D API.
- No custom config, use the current default config.
- If custom config presents, but there's no listener, use 0.0.0.0:53.
- Try listening on current ip+port config, if ok, ctrld could be a
direct listener with current setup, moving on.
- If failed, trying 127.0.0.1:53.
- If failed, trying current ip + port 5354
- If still failed, pick a random ip:port pair, retry until listening ok.
With this flow, thing is more predictable/stable, and help removing the
Config interface for router.
