feat(ffi): add config server client bindings (#2320)

Add config server client support for the C FFI and Android JNI bindings.

Reuse the existing easytier::web_client::run_web_client path and 
NetworkInstanceManager; OHOS is unchanged.

Report successful remote config apply/delete operations through a 
callback, with one JSON event per affected instance.

Keep the config server client and FFI data plane mutually exclusive: once 
either side is in use, the other side returns an error instead of sharing
lifecycle state.

easytier-contrib/easytier-android-jni/src/network_api.rs

@@ -0,0 +1,210 @@
+use std::{ffi::CStr, ptr};
+
+use easytier::proto::api::manage::{NetworkInstanceRunningInfo, NetworkInstanceRunningInfoMap};
+use easytier_ffi::{
+    KeyValuePair, collect_network_infos, parse_config, retain_network_instance,
+    run_network_instance, set_tun_fd,
+};
+use jni::JNIEnv;
+use jni::objects::{JClass, JObjectArray, JString};
+use jni::sys::{jint, jstring};
+
+use crate::{
+    error::{get_last_error, throw_exception},
+    strings::jstring_to_cstring,
+};
+
+pub(crate) fn set_tun_fd_jni(
+    mut env: JNIEnv,
+    _class: JClass,
+    inst_name: JString,
+    fd: jint,
+) -> jint {
+    let inst_name_cstr = match jstring_to_cstring(&mut env, &inst_name) {
+        Ok(cstr) => cstr,
+        Err(e) => {
+            throw_exception(&mut env, &format!("Invalid instance name: {}", e));
+            return -1;
+        }
+    };
+    unsafe {
+        let result = set_tun_fd(inst_name_cstr.as_ptr(), fd);
+        if result != 0
+            && let Some(error) = get_last_error()
+        {
+            throw_exception(&mut env, &error);
+        }
+        result
+    }
+}
+
+pub(crate) fn parse_config_jni(mut env: JNIEnv, _class: JClass, config: JString) -> jint {
+    let config_cstr = match jstring_to_cstring(&mut env, &config) {
+        Ok(cstr) => cstr,
+        Err(e) => {
+            throw_exception(&mut env, &format!("Invalid config string: {}", e));
+            return -1;
+        }
+    };
+    unsafe {
+        let result = parse_config(config_cstr.as_ptr());
+        if result != 0
+            && let Some(error) = get_last_error()
+        {
+            throw_exception(&mut env, &error);
+        }
+        result
+    }
+}
+
+pub(crate) fn run_network_instance_jni(mut env: JNIEnv, _class: JClass, config: JString) -> jint {
+    let config_cstr = match jstring_to_cstring(&mut env, &config) {
+        Ok(cstr) => cstr,
+        Err(e) => {
+            throw_exception(&mut env, &format!("Invalid config string: {}", e));
+            return -1;
+        }
+    };
+    unsafe {
+        let result = run_network_instance(config_cstr.as_ptr());
+        if result != 0
+            && let Some(error) = get_last_error()
+        {
+            throw_exception(&mut env, &error);
+        }
+        result
+    }
+}
+
+pub(crate) fn retain_network_instance_jni(
+    mut env: JNIEnv,
+    _class: JClass,
+    instance_names: JObjectArray,
+) -> jint {
+    if instance_names.is_null() {
+        return retain_all(&mut env);
+    }
+
+    let array_length = match env.get_array_length(&instance_names) {
+        Ok(len) => len as usize,
+        Err(e) => {
+            throw_exception(&mut env, &format!("Failed to get array length: {:?}", e));
+            return -1;
+        }
+    };
+
+    if array_length == 0 {
+        return retain_all(&mut env);
+    }
+
+    let mut c_strings = Vec::with_capacity(array_length);
+    let mut c_string_ptrs = Vec::with_capacity(array_length);
+
+    for i in 0..array_length {
+        let java_string = match env.get_object_array_element(&instance_names, i as i32) {
+            Ok(obj) => obj,
+            Err(e) => {
+                throw_exception(
+                    &mut env,
+                    &format!("Failed to get array element {}: {:?}", i, e),
+                );
+                return -1;
+            }
+        };
+
+        if java_string.is_null() {
+            continue;
+        }
+
+        let jstring = JString::from(java_string);
+        let c_string = match jstring_to_cstring(&mut env, &jstring) {
+            Ok(cstr) => cstr,
+            Err(e) => {
+                throw_exception(
+                    &mut env,
+                    &format!("Invalid instance name at index {}: {}", i, e),
+                );
+                return -1;
+            }
+        };
+
+        c_string_ptrs.push(c_string.as_ptr());
+        c_strings.push(c_string);
+    }
+
+    unsafe {
+        let result = retain_network_instance(c_string_ptrs.as_ptr(), c_string_ptrs.len());
+        if result != 0
+            && let Some(error) = get_last_error()
+        {
+            throw_exception(&mut env, &error);
+        }
+        result
+    }
+}
+
+fn retain_all(env: &mut JNIEnv) -> jint {
+    unsafe {
+        let result = retain_network_instance(ptr::null(), 0);
+        if result != 0
+            && let Some(error) = get_last_error()
+        {
+            throw_exception(env, &error);
+        }
+        result
+    }
+}
+
+pub(crate) fn collect_network_infos_jni(
+    mut env: JNIEnv,
+    _class: JClass,
+    max_length: jint,
+) -> jstring {
+    let max_length = max_length.max(0) as usize;
+    let mut infos = vec![
+        KeyValuePair {
+            key: ptr::null(),
+            value: ptr::null(),
+        };
+        max_length
+    ];
+
+    unsafe {
+        let count = collect_network_infos(infos.as_mut_ptr(), max_length);
+        if count < 0 {
+            if let Some(error) = get_last_error() {
+                throw_exception(&mut env, &error);
+            }
+            return ptr::null_mut();
+        }
+
+        let mut ret = NetworkInstanceRunningInfoMap::default();
+        for info in infos.iter().take(count as usize) {
+            let key_ptr = info.key;
+            let val_ptr = info.value;
+            if key_ptr.is_null() || val_ptr.is_null() {
+                break;
+            }
+
+            let key = CStr::from_ptr(key_ptr).to_string_lossy();
+            let val = CStr::from_ptr(val_ptr).to_string_lossy();
+            let value = match serde_json::from_str::<NetworkInstanceRunningInfo>(val.as_ref()) {
+                Ok(v) => v,
+                Err(_) => {
+                    throw_exception(&mut env, "Failed to parse JSON");
+                    continue;
+                }
+            };
+            ret.map.insert(key.to_string(), value);
+        }
+
+        let json_str = serde_json::to_string(&ret).unwrap_or_else(|_| "{}".to_string());
+        match env.new_string(&json_str) {
+            Ok(jstr) => jstr.into_raw(),
+            Err(_) => {
+                throw_exception(&mut env, "Failed to create JSON string");
+                ptr::null_mut()
+            }
+        }
+    }
+}