[dns-operations] getcacheddhcpresultsforcurrentconfig

[Florian Weimer]

* Roy Arends:

> Has anyone observed the string “getcacheddhcpresultsforcurrentconfig” before? 
>
> It is one of the most queried for top level domains by many different
> source addresses. My suspicion is that is configured as a search
> domain in some (equivalent of) resolv,conf on a widespread device.

This software <https://github.com/SivanLiu/HwFrameWorkSource> seems to
use the string for in-band signaling:

|   if (dhcpResults != null) {
|       WifiStateMachine.this.stopIpClient();
|       dhcpResults.domains = "getCachedDhcpResultsForCurrentConfig";

<https://github.com/SivanLiu/HwFrameWorkSource/blob/0c5f7a1ad8074c12b0a830e49e6e1e1df575e0cd/Mate20_9_0_0/src/main/java/com/android/server/wifi/WifiStateMachine.java#L2573>

I can't read the README file unfortunately, but perhaps it's
sufficiently widely deployed to explain the observations.

Thanks,
Florian