Skip packet on NBL allocation failure properly

Should NBL allocation persist to fail, the receive ring could eventually
fill up as there will be no TunReturnNetBufferLists() calls to advance
its head.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/wintun.c b/wintun.c
index 3275cd8..f45f301 100644
--- a/wintun.c
+++ b/wintun.c
@@ -503,6 +503,8 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
         if (!Nbl)
         {
             InterlockedIncrement64((LONG64 *)&Ctx->Statistics.ifInDiscards);
+            KeWaitForSingleObject(&Ctx->Device.Receive.ActiveNbls.Empty, Executive, KernelMode, FALSE, NULL);
+            InterlockedSetU(&Ring->Head, RingHead);
             continue;
         }