解决win7不能启动的问题

switch/wintun/src/util.rs

@@ -0,0 +1,66 @@
+use winapi::{
+    shared::ntdef::{LANG_NEUTRAL, SUBLANG_DEFAULT},
+    um::{winbase, winnt::MAKELANGID},
+};
+
+use std::mem::MaybeUninit;
+use std::ptr;
+
+use widestring::U16Str;
+
+/// A wrapper struct that allows a type to be Send and Sync
+pub(crate) struct UnsafeHandle<T>(pub T);
+
+/// We never read from the pointer. It only serves as a handle we pass to the kernel or C code that
+/// doesn't have the same mutable aliasing restrictions we have in Rust
+unsafe impl<T> Send for UnsafeHandle<T> {}
+unsafe impl<T> Sync for UnsafeHandle<T> {}
+
+/// Returns a a human readable error message from a windows error code
+pub fn get_error_message(err_code: u32) -> String {
+    const LEN: usize = 256;
+    let mut buf = MaybeUninit::<[u16; LEN]>::uninit();
+
+    //SAFETY: name is a allocated on the stack above therefore it must be valid, non-null and
+    //aligned for u16
+    let first = unsafe { *buf.as_mut_ptr() }.as_mut_ptr();
+    //Write default null terminator in case WintunGetAdapterName leaves name unchanged
+    unsafe { first.write(0u16) };
+    let chars_written = unsafe {
+        winbase::FormatMessageW(
+            winbase::FORMAT_MESSAGE_FROM_SYSTEM | winbase::FORMAT_MESSAGE_IGNORE_INSERTS,
+            ptr::null(),
+            err_code,
+            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT) as u32,
+            first,
+            LEN as u32,
+            ptr::null_mut(),
+        )
+    };
+
+    //SAFETY: first is a valid, non-null, aligned, pointer
+    format!(
+        "{} ({})",
+        unsafe { U16Str::from_ptr(first, chars_written as usize) }.to_string_lossy(),
+        err_code
+    )
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub struct Version {
+    pub major: u16,
+    pub minor: u16,
+}
+
+/// Returns the major and minor version of the wintun driver
+pub fn get_running_driver_version(wintun: &crate::Wintun) -> Result<Version, ()> {
+    let version = unsafe { wintun.WintunGetRunningDriverVersion() };
+    if version == 0 {
+        Err(())
+    } else {
+        Ok(Version {
+            major: ((version >> 16) & 0xFF) as u16,
+            minor: (version & 0xFF) as u16,
+        })
+    }
+}