From 200da2fba11aaff76de262116dcc0616209acba5 Mon Sep 17 00:00:00 2001
From: basil00 <basil@reqrypt.org>
Date: Sat, 23 Sep 2017 20:09:04 +0800
Subject: [PATCH] Complete WinDivertSend() IO requests immediately.

Currently, WinDivert waits until injection completes before completing the
corresponding IO request.  However, packet injection may take an arbitrarily
long time, such as waiting for a user-mode application.

The new version completes the IO request immediately, provided the call to the
corresponding WFP packet injection function did not return an error, thus
eliminating the problem.  The disadvantage is that some packet injection
errors may no longer be detected.
---
 sys/windivert.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/sys/windivert.c b/sys/windivert.c
index 76013fe..f637b5e 100644
--- a/sys/windivert.c
+++ b/sys/windivert.c
@@ -1534,25 +1534,29 @@ windivert_write_bad_packet:
     {
         status = FwpsInjectForwardAsync0(handle, (HANDLE)context->priority,
             0, (isipv4? AF_INET: AF_INET6), UNSPECIFIED_COMPARTMENT_ID,
-            addr->IfIdx, buffers, windivert_inject_complete, (HANDLE)request);
+            addr->IfIdx, buffers, windivert_inject_complete, NULL);
     }
     else if (addr->Direction == WINDIVERT_DIRECTION_OUTBOUND)
     {
         status = FwpsInjectNetworkSendAsync0(handle,
             (HANDLE)context->priority, 0, UNSPECIFIED_COMPARTMENT_ID, buffers,
-            windivert_inject_complete, (HANDLE)request);
+            windivert_inject_complete, NULL);
     }
     else
     {
         status = FwpsInjectNetworkReceiveAsync0(handle, 
             (HANDLE)context->priority, 0, UNSPECIFIED_COMPARTMENT_ID,
             addr->IfIdx, addr->SubIfIdx, buffers, windivert_inject_complete,
-            (HANDLE)request);
+            NULL);
     }
 
 windivert_write_exit:
 
-    if (!NT_SUCCESS(status))
+    if (NT_SUCCESS(status))
+    {
+        WdfRequestCompleteWithInformation(request, status, data_len);
+    }
+    else
     {
         DEBUG_ERROR("failed to inject packet", status);
         if (buffers != NULL)
@@ -1578,16 +1582,14 @@ windivert_write_exit:
 static void NTAPI windivert_inject_complete(VOID *context,
     NET_BUFFER_LIST *buffers, BOOLEAN dispatch_level)
 {
-    WDFREQUEST request = (WDFREQUEST)context;
     PMDL mdl;
     PVOID data;
     PNET_BUFFER buffer;
     size_t length = 0;
     NTSTATUS status;
+    UNREFERENCED_PARAMETER(context);
     UNREFERENCED_PARAMETER(dispatch_level);
 
-    DEBUG("COMPLETE: write/inject packet complete (request=%p)", request);
-
     buffer = NET_BUFFER_LIST_FIRST_NB(buffers);
     status = NET_BUFFER_LIST_STATUS(buffers);
     if (NT_SUCCESS(status))
@@ -1606,7 +1608,6 @@ static void NTAPI windivert_inject_complete(VOID *context,
     }
     IoFreeMdl(mdl);
     FwpsFreeNetBufferList0(buffers);
-    WdfRequestCompleteWithInformation(request, status, length);
 }
 
 /*