feat: Android enhancements

Cargo.toml

@@ -25,6 +25,8 @@ netlink-sys = "0.8.8"
 
 [target.'cfg(target_os = "android")'.dependencies]
 dlopen2 = { version = "0.8.2", default-features = false }
+jni = { version = "0.21.1", optional = true }
+ndk-context = { version = "0.1.1", optional = true }
 once_cell = "1"
 
 [target.'cfg(windows)'.dependencies.windows-sys]
@@ -53,9 +55,10 @@ block2 = "0.6"
 serde_json = "1.0"
 
 [features]
-default = ["gateway", "apple-system-configuration-extra"]
+default = ["gateway", "apple-system-configuration-extra", "android-extra"]
 serde = ["dep:serde", "mac-addr/serde", "ipnet/serde"]
 gateway = []
+android-extra = ["dep:jni", "dep:ndk-context"]
 apple-system-configuration-extra = [
     "objc2-system-configuration/SCPreferences",
     "objc2-system-configuration/SCDynamicStore",

README.md

@@ -50,6 +50,9 @@ For more details, see [examples][examples-url] or [doc][doc-url].
 - `apple-system-configuration-extra` (default)
   - Enables deeper Apple metadata enrichment using `SystemConfiguration` APIs.
   - On Apple targets, this adds metadata such as interface display names, DHCP hints, and iOS DNS resolver lookup when the platform exposes them.
+- `android-extra` (default)
+  - Enables deeper Android metadata enrichment using Android platform APIs through JNI bindings.
+  - On Android, this can add metadata such as traffic stats, DNS servers, DHCP hints, and Wi-Fi link speed when the app provides the required Android context and permissions.
 
 To opt out of the deeper Apple enrichment while keeping gateway helpers:
 
@@ -62,6 +65,9 @@ netdev = { version = "0.43", default-features = false, features = ["gateway"] }
 `netdev` links `SystemConfiguration.framework` automatically on `macOS` and `iOS` through the crate's own build script.
 If your final app link is performed by Xcode, you may still need to add `SystemConfiguration.framework` to the app target manually.
 
+## Android behavior
+If you want Android-specific values such as DNS servers, DHCP hints, or Wi-Fi link speed, your app may still need to initialize the Android context for Rust and declare Android permissions such as `ACCESS_NETWORK_STATE` and `ACCESS_WIFI_STATE`.
+
 ## Project History
 This crate was originally published as [default-net][default-net-crates-io-url] 
 and later rebranded to `netdev` by the author myself for future expansion, clearer naming, and long-term maintenance.