Provide a easy way to access bpf maps from java

A wrapper for bpf map opening, reading/writing, and iteration.

Bug: 173167302
Test: atest BpfMapTest

Change-Id: I792b41978b322c9e4969cd7b6c35d6978ab86bc4
diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index d8557ad..0c9801c 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -60,8 +60,12 @@
         "com.android.tethering",
     ],
     min_sdk_version: "30",
+    include_dirs: [
+        // TODO: use the libbpf_android_headers instead of just including the header files.
+        "system/bpf/libbpf_android/include/",
+    ],
     srcs: [
-        "jni/android_net_util_TetheringUtils.cpp",
+        "jni/*.cpp",
     ],
     shared_libs: [
         "liblog",