Add Windows version check function

1 files changed, 41 insertions, 1 deletions

diff --git a/talpid-core/src/dns/windows/mod.rs b/talpid-core/src/dns/windows/mod.rs
index 646458aca1..dbebcfc3e9 100644
--- a/talpid-core/src/dns/windows/mod.rs
+++ b/talpid-core/src/dns/windows/mod.rs
@@ -1,9 +1,13 @@
 use crate::logging::windows::{log_sink, LogSink};
 
 use log::{error, trace, warn};
-use std::{io, net::IpAddr, path::Path};
+use std::{io, mem, net::IpAddr, path::Path, ptr};
 use talpid_types::ErrorExt;
 use widestring::WideCString;
+use winapi::um::{
+    libloaderapi::{GetModuleHandleA, GetProcAddress},
+    winnt::RTL_OSVERSIONINFOW,
+};
 use winreg::{
     enums::{HKEY_LOCAL_MACHINE, REG_MULTI_SZ},
     transaction::Transaction,
@@ -186,6 +190,42 @@ fn reset_dns_cache_policy() -> Result<(), Error> {
     }
 }
 
+fn is_minimum_windows10() -> bool {
+    match is_minimum_windows10_inner() {
+        Ok(result) => result,
+        Err(error) => {
+            error!(
+                "{}",
+                error.display_chain_with_msg("OS version check failed")
+            );
+            false
+        }
+    }
+}
+
+fn is_minimum_windows10_inner() -> Result<bool, io::Error> {
+    let rtl_get_version: extern "stdcall" fn(*mut RTL_OSVERSIONINFOW);
+
+    let ntdll = unsafe { GetModuleHandleA(b"ntdll\0" as *const _ as *const i8) };
+    if ntdll == ptr::null_mut() {
+        return Err(io::Error::last_os_error());
+    }
+
+    let function_address =
+        unsafe { GetProcAddress(ntdll, b"RtlGetVersion\0" as *const _ as *const i8) };
+    if function_address == ptr::null_mut() {
+        return Err(io::Error::last_os_error());
+    }
+
+    rtl_get_version = unsafe { mem::transmute(function_address) };
+
+    let mut version_info: RTL_OSVERSIONINFOW = unsafe { std::mem::zeroed() };
+    version_info.dwOSVersionInfoSize = mem::size_of_val(&version_info) as u32;
+    rtl_get_version(&mut version_info);
+
+    Ok(version_info.dwMajorVersion >= 10)
+}
+
 
 ffi_error!(InitializationResult, Error::Initialization);
 ffi_error!(DeinitializationResult, Error::Deinitialization);