Enable IPv6 for WireGuard interface

2 files changed, 57 insertions, 9 deletions

diff --git a/talpid-core/src/tunnel/mod.rs b/talpid-core/src/tunnel/mod.rs
index 0f8a902406..afee640829 100644
--- a/talpid-core/src/tunnel/mod.rs
+++ b/talpid-core/src/tunnel/mod.rs
@@ -3,7 +3,6 @@ use crate::logging;
 #[cfg(not(target_os = "android"))]
 use std::collections::HashMap;
 use std::{
-    ffi::OsString,
     io,
     net::{IpAddr, Ipv4Addr, Ipv6Addr},
     path::{Path, PathBuf},
@@ -348,14 +347,27 @@ fn try_enabling_ipv6(tunnel_parameters: &TunnelParameters) -> Result<()> {
         return Err(Error::EnableIpv6Error);
     }
 
-    let alias = match tunnel_parameters {
+    let guid_string: String;
+
+    let guid = match tunnel_parameters {
         TunnelParameters::OpenVpn(..) => {
-            crate::winnet::get_tap_interface_alias().map_err(Error::WinnetError)?
+            // TODO: This status check can be removed if it is certain
+            // that `enable_ipv6_for_adapter` is reliable.
+            let status =
+                crate::winnet::get_tap_interface_ipv6_status().map_err(Error::WinnetError)?;
+            if status {
+                return Ok(());
+            }
+
+            let alias = crate::winnet::get_tap_interface_alias().map_err(Error::WinnetError)?;
+            guid_string =
+                crate::winnet::interface_alias_to_guid(&alias).map_err(Error::WinnetError)?;
+            &guid_string
         }
-        TunnelParameters::Wireguard(..) => OsString::from("wg-mullvad"),
+        TunnelParameters::Wireguard(..) => "{AFE43773-E1F8-4EBB-8536-576AB86AFE9A}",
     };
 
-    crate::winnet::enable_ipv6_for_adapter(&alias).map_err(Error::WinnetError)
+    crate::winnet::enable_ipv6_for_adapter(&guid).map_err(Error::WinnetError)
 }
 
 #[cfg(target_os = "windows")]
diff --git a/talpid-core/src/winnet.rs b/talpid-core/src/winnet.rs
index 3e7a52bf75..534dab5228 100644
--- a/talpid-core/src/winnet.rs
+++ b/talpid-core/src/winnet.rs
@@ -25,6 +25,10 @@ pub enum Error {
     #[error(display = "Failed to enable IPv6 on the network interface")]
     EnableIpv6,
 
+    /// Failed to enable IPv6 on the network interface.
+    #[error(display = "Failed to obtain GUID for the network interface")]
+    GetInterfaceGuid,
+
     /// Failed to read IPv6 status on the TAP network interface.
     #[error(display = "Failed to read IPv6 status on the TAP network interface")]
     GetIpv6Status,
@@ -71,13 +75,13 @@ pub fn ensure_best_metric_for_interface(interface_alias: &str) -> Result<bool, E
 }
 
 /// Enables IPv6 for a given interface.
-pub fn enable_ipv6_for_adapter(interface_alias: &OsStr) -> Result<(), Error> {
-    let interface_alias_ws =
-        WideCString::from_os_str(interface_alias).map_err(Error::InvalidInterfaceAlias)?;
+pub fn enable_ipv6_for_adapter(interface_guid: &str) -> Result<(), Error> {
+    let interface_guid_ws =
+        WideCString::from_str(interface_guid).map_err(Error::InvalidInterfaceAlias)?;
 
     let result = unsafe {
         WinNet_EnableIpv6ForAdapter(
-            interface_alias_ws.as_ptr(),
+            interface_guid_ws.as_ptr(),
             Some(log_sink),
             logging_context(),
         )
@@ -133,6 +137,30 @@ pub fn get_tap_interface_alias() -> Result<OsString, Error> {
     Ok(alias.to_os_string())
 }
 
+/// Determines the interface guid for a given adapter alias.
+pub fn interface_alias_to_guid(interface_alias: &OsStr) -> Result<String, Error> {
+    let interface_alias =
+        WideCString::from_os_str(interface_alias).map_err(Error::InvalidInterfaceAlias)?;
+    let mut guid_ptr: *mut wchar_t = ptr::null_mut();
+    let status = unsafe {
+        WinNet_InterfaceAliasToGuid(
+            interface_alias.as_ptr(),
+            &mut guid_ptr as *mut _,
+            Some(log_sink),
+            logging_context(),
+        )
+    };
+
+    if !status {
+        return Err(Error::GetInterfaceGuid);
+    }
+
+    let guid = unsafe { WideCString::from_ptr_str(guid_ptr) };
+    unsafe { WinNet_ReleaseString(guid_ptr) };
+
+    Ok(guid.to_string_lossy())
+}
+
 #[allow(dead_code)]
 #[repr(u32)]
 pub enum WinNetAddrFamily {
@@ -428,6 +456,14 @@ mod api {
             sink_context: *const u8,
         ) -> bool;
 
+        #[link_name = "WinNet_InterfaceAliasToGuid"]
+        pub fn WinNet_InterfaceAliasToGuid(
+            interface_alias: *const wchar_t,
+            interface_guid: *mut *mut wchar_t,
+            sink: Option<LogSink>,
+            sink_context: *const u8,
+        ) -> bool;
+
         #[link_name = "WinNet_ReleaseString"]
         pub fn WinNet_ReleaseString(string: *mut wchar_t);