Add support for dynamic Wintun library loading and update dependencies (

#70)

.gitignore

@@ -6,3 +6,4 @@ target/
 **/*.rs.bk
 Cargo.lock
 wintun.dll
+.history

Cargo.toml

@@ -30,6 +30,7 @@ nix = { version = "0.29", features = ["ioctl"] }
 
 [target.'cfg(target_os = "windows")'.dependencies]
 wintun = { version = "0.4", features = ["panic_on_unsent_packets"] }
+libloading = "0.8.3"
 
 [target.'cfg(any(target_os = "macos", target_os = "freebsd"))'.dependencies]
 ipnet = "2"

README.md

@@ -135,4 +135,5 @@ pub extern "C" fn start_tun(fd: std::os::raw::c_int) {
 Windows
 -----
 You need to copy the [wintun.dll](https://wintun.net/) file which matches your architecture to 
-the same directory as your executable and run your program as administrator.
+the same directory as your executable or can set `WINTUN_LIBARAY_PATH` to the dll file and run your program as administrator.
+

src/error.rs

@@ -53,6 +53,10 @@ pub enum Error {
     #[cfg(target_os = "windows")]
     #[error(transparent)]
     WintunError(#[from] wintun::Error),
+
+    #[cfg(target_os = "windows")]
+    #[error(transparent)]
+    LibloadingError(#[from] libloading::Error),
 }
 
 impl From<Error> for std::io::Error {

src/platform/windows/device.rs

@@ -31,7 +31,12 @@ pub struct Device {
 impl Device {
     /// Create a new `Device` for the given `Configuration`.
     pub fn new(config: &Configuration) -> Result<Self> {
-        let wintun = unsafe { wintun::load()? };
+        let wintun = unsafe {
+            let wintun_libray_path =
+                std::env::var("WINTUN_LIBARAY_PATH").unwrap_or("wintun.dll".to_string());
+            let wintun = libloading::Library::new(wintun_libray_path)?;
+            wintun::load_from_library(wintun)?
+        };
         let tun_name = config.tun_name.as_deref().unwrap_or("wintun");
         let guid = config.platform_config.device_guid;
         let adapter = match wintun::Adapter::open(&wintun, tun_name) {