introduce ffi for easytier (#791)

easytier-contrib/easytier-ffi/src/lib.rs

@@ -0,0 +1,199 @@
+use std::sync::Mutex;
+
+use dashmap::DashMap;
+use easytier::{
+    common::config::{ConfigLoader as _, TomlConfigLoader},
+    launcher::NetworkInstance,
+};
+
+static INSTANCE_MAP: once_cell::sync::Lazy<DashMap<String, NetworkInstance>> =
+    once_cell::sync::Lazy::new(DashMap::new);
+
+static ERROR_MSG: once_cell::sync::Lazy<Mutex<Vec<u8>>> =
+    once_cell::sync::Lazy::new(|| Mutex::new(Vec::new()));
+
+#[repr(C)]
+pub struct KeyValuePair {
+    pub key: *const std::ffi::c_char,
+    pub value: *const std::ffi::c_char,
+}
+
+fn set_error_msg(msg: &str) {
+    let bytes = msg.as_bytes();
+    let mut msg_buf = ERROR_MSG.lock().unwrap();
+    let len = bytes.len();
+    msg_buf.resize(len, 0);
+    msg_buf[..len].copy_from_slice(bytes);
+}
+
+#[no_mangle]
+pub extern "C" fn get_error_msg(out: *mut *const std::ffi::c_char) {
+    let msg_buf = ERROR_MSG.lock().unwrap();
+    if msg_buf.is_empty() {
+        unsafe {
+            *out = std::ptr::null();
+        }
+        return;
+    }
+    let cstr = std::ffi::CString::new(&msg_buf[..]).unwrap();
+    unsafe {
+        *out = cstr.into_raw();
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn free_string(s: *const std::ffi::c_char) {
+    if s.is_null() {
+        return;
+    }
+    unsafe {
+        let _ = std::ffi::CString::from_raw(s as *mut std::ffi::c_char);
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn parse_config(cfg_str: *const std::ffi::c_char) -> std::ffi::c_int {
+    let cfg_str = unsafe {
+        assert!(!cfg_str.is_null());
+        std::ffi::CStr::from_ptr(cfg_str)
+            .to_string_lossy()
+            .into_owned()
+    };
+
+    if let Err(e) = TomlConfigLoader::new_from_str(&cfg_str) {
+        set_error_msg(&format!("failed to parse config: {:?}", e));
+        return -1;
+    }
+
+    0
+}
+
+#[no_mangle]
+pub extern "C" fn run_network_instance(cfg_str: *const std::ffi::c_char) -> std::ffi::c_int {
+    let cfg_str = unsafe {
+        assert!(!cfg_str.is_null());
+        std::ffi::CStr::from_ptr(cfg_str)
+            .to_string_lossy()
+            .into_owned()
+    };
+    let cfg = match TomlConfigLoader::new_from_str(&cfg_str) {
+        Ok(cfg) => cfg,
+        Err(e) => {
+            set_error_msg(&format!("failed to parse config: {}", e));
+            return -1;
+        }
+    };
+
+    let inst_name = cfg.get_inst_name();
+
+    if INSTANCE_MAP.contains_key(&inst_name) {
+        set_error_msg("instance already exists");
+        return -1;
+    }
+
+    let mut instance = NetworkInstance::new(cfg);
+    if let Err(e) = instance.start().map_err(|e| e.to_string()) {
+        set_error_msg(&format!("failed to start instance: {}", e));
+        return -1;
+    }
+
+    INSTANCE_MAP.insert(inst_name, instance);
+
+    0
+}
+
+#[no_mangle]
+pub extern "C" fn retain_network_instance(
+    inst_names: *const *const std::ffi::c_char,
+    length: usize,
+) -> std::ffi::c_int {
+    if length == 0 {
+        INSTANCE_MAP.clear();
+        return 0;
+    }
+
+    let inst_names = unsafe {
+        assert!(!inst_names.is_null());
+        std::slice::from_raw_parts(inst_names, length)
+            .iter()
+            .map(|&name| {
+                assert!(!name.is_null());
+                std::ffi::CStr::from_ptr(name)
+                    .to_string_lossy()
+                    .into_owned()
+            })
+            .collect::<Vec<_>>()
+    };
+
+    let _ = INSTANCE_MAP.retain(|k, _| inst_names.contains(k));
+
+    0
+}
+
+#[no_mangle]
+pub extern "C" fn collect_network_infos(
+    infos: *mut KeyValuePair,
+    max_length: usize,
+) -> std::ffi::c_int {
+    if max_length == 0 {
+        return 0;
+    }
+
+    let infos = unsafe {
+        assert!(!infos.is_null());
+        std::slice::from_raw_parts_mut(infos, max_length)
+    };
+
+    let mut index = 0;
+    for instance in INSTANCE_MAP.iter() {
+        if index >= max_length {
+            break;
+        }
+        let key = instance.key();
+        let Some(value) = instance.get_running_info() else {
+            continue;
+        };
+        // convert value to json string
+        let value = match serde_json::to_string(&value) {
+            Ok(value) => value,
+            Err(e) => {
+                set_error_msg(&format!("failed to serialize instance info: {}", e));
+                return -1;
+            }
+        };
+
+        infos[index] = KeyValuePair {
+            key: std::ffi::CString::new(key.clone()).unwrap().into_raw(),
+            value: std::ffi::CString::new(value).unwrap().into_raw(),
+        };
+        index += 1;
+    }
+
+    index as std::ffi::c_int
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse_config() {
+        let cfg_str = r#"
+            inst_name = "test"
+            network = "test_network"
+            fdsafdsa
+        "#;
+        let cstr = std::ffi::CString::new(cfg_str).unwrap();
+        assert_eq!(parse_config(cstr.as_ptr()), 0);
+    }
+
+    #[test]
+    fn test_run_network_instance() {
+        let cfg_str = r#"
+            inst_name = "test"
+            network = "test_network"
+        "#;
+        let cstr = std::ffi::CString::new(cfg_str).unwrap();
+        assert_eq!(run_network_instance(cstr.as_ptr()), 0);
+    }
+}