System.Net.NetworkInformation needs Android PAL

[marek-safar]

Currently, System.Net.NetworkInformation implementation on Android falls back to Linux PAL. This needs to change because starting from API 24 Android restricts access to many files in the /sys filesystem which makes the API unsupported.

Right now the APIs fail with System.UnauthorizedAccessException. We need to write an Android-specific PAL layer that uses Java APIs via JNI to access the information to not break developers migrating from existing Mono based BCL.

/cc @steveisok

Tagging subscribers to this area: @dotnet/ncl
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Currently, System.Net.NetworkInformation implementation on Android falls back to Linux PAL. This needs to change because starting from API 24 Android restricts access to many files in the /sys filesystem which makes the API unsupported.

We should write Android-specific PAL layer which uses Java APIs via JNI to access the information.

/cc @steveisok

Author:	marek-safar
Assignees:	-
Labels:	area-System.Net, untriaged
Milestone:	-

[filipnavara]

For reference, the Xamarin.Android implementation of the code resides here. Mono used to call it through several indirections.

[wfurt]

It would be good to get list of failing methods & properties @marek-safar. I made changes in the past to linked GetAllNetworkInterfaces() do depend less on /proc & /sys. It certainly feels better to throw PNSP or have alternative implementation than getting access violation. I would be curious to see how big that difference is.

[marek-safar]

@wfurt see #50567

[wfurt]

That list does not give the list of files @marek-safar. But it seems to be mostly stats.

[marek-safar]

@wfurt perhaps I misunderstood the ask, what are you looking for exactly?

[wfurt]

That is ok. I was primarily wondering how much code we will need to replace. Number of test is somewhat approximation. If there are only few functions we may simply add alternatives instead of doing whole new pal. there is already some precedent for that.