Question with dnsmasq-2.83-1 (resolv.conf.auto location)

[kokitodaito]

Hi all,

I met a problem with the new dnsmasq configuration, in dhcp.conf the reslovfile path has changed to /tmp/resolv.conf.d/resolv.conf.auto but this file doesn't exist, which will cause dhcp problem.

Does anyone know why this path was changed?

[vgaetera]

base-files: move /tmp/resolv.conf.auto to /tmp/resolv.conf.d/

dnsmasq: switch to /tmp/resolv.conf.d/resolv.conf.auto

[kokitodaito]

Thank you!!

[lleachii]

@kokitodaito

the reslovfile path has changed to /tmp/resolv.conf.d/resolv.conf.auto but this file doesn't exist, which will cause dhcp problem.

Be advised, using an older router config file with that newer dnsmasq seems to break it. I wasn't able to determine the exact issue before I had to recover; but I did see the errors in the log that you noted.

Issues seen when it occurred:

• no IPv4 addressed issued to LAN client via DHCP

I have the backup file if anyone has clues and wants to check (I do have a backup device to load it; but that may take time - as that is standby for recovery ).

I was running a MAR 2020 Snapshot and attempted to upgrade, the firmware failed to boot, so I flashed 19.07.6.

I upgraded my dnsmasq before upgrading due to the CVEs; if that gives any hints.

[hnyman]

@kokitodaito

the reslovfile path has changed to /tmp/resolv.conf.d/resolv.conf.auto

@lleachii

Be advised, using an older router config file with that newer dnsmasq seems to break it. I wasn't able to determine the exact issue before I had to recover;

• Downgrade path from master to 19.07 is not supported for dnsmasq.
• If you move from the 19.07 to master, the config gets migrated ok. (unless you later restore a 19.07 version of the config file...)

The resolv directory in dnsmasq config was changed a year ago in January 2020 by dangowrt with commit cd48d8d342:

https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=cd48d8d3420dd4df03daaa548227ceb487ba7104

That broke also master configs in sysupgrade, so a migration was provided two days later by 6a2855212:

https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=6a2855212096d2c486961a0841b037bae4b75de7

Those commits effectively block downgrading from master to 19.07 unless you adjust the dnsmasq config to the dnsmasq 19.07 expectations.

Ps.
I include a config migration script in my own 19.07 builds, so that 6a2855212 gets applied reverted when I move from master to 19.07.