api: port GetInterface member from wireguard-go

Mind that this also fixes the order of adapter detection checks. A fast
test to eliminate non-Wintun adapters from iteration to speed things up
rendered the method incapable of detecting a non-Wintun adapter with the
name we are looking for.

ERROR_OBJECT_NOT_FOUND was replaced with ERROR_FILE_NOT_FOUND.

Signed-off-by: Simon Rozman <simon@rozman.si>

1 files changed, 18 insertions, 0 deletions

diff --git a/api/api.h b/api/api.h
index cda22b3..6b05de2 100644
--- a/api/api.h
+++ b/api/api.h
@@ -36,3 +36,21 @@ NciInit();
 
 void
 NciCleanup();
+
+#define MAX_POOL 256
+#define MAX_INSTANCE_ID MAX_PATH /* TODO: Is MAX_PATH always enough? */
+
+typedef struct _WINTUN_ADAPTER
+{
+    GUID CfgInstanceID;
+    WCHAR DevInstanceID[MAX_INSTANCE_ID];
+    DWORD LuidIndex;
+    DWORD IfType;
+    WCHAR Pool[MAX_POOL];
+} WINTUN_ADAPTER;
+
+VOID WINAPI
+WintunFreeAdapter(_In_ WINTUN_ADAPTER *Adapter);
+
+_Return_type_success_(return == 0) DWORD WINAPI
+    WintunGetAdapter(_In_z_count_c_(MAX_POOL) LPCWSTR Pool, _In_z_ LPCWSTR IfName, _Out_ WINTUN_ADAPTER **Adapter);