In Windows TAP driver, refactor DHCP/ARP packet injection code to

use a DPC (deferred procedure call) to defer packet injection until
IRQL < DISPATCH_LEVEL, rather than calling NdisMEthIndicateReceive
in the context of AdapterTransmit.  This is an attempt to reduce kernel
stack usage, and prevent EXCEPTION_DOUBLE_FAULT BSODs that have been
observed on Vista.  Updated TAP driver version number to 9.6. 


git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@4606 e7ae566f-a301-0410-adde-c780ea21d3b5

1 files changed, 15 insertions, 0 deletions

diff --git a/tap-win32/types.h b/tap-win32/types.h
index d424521..4adee6a 100755
--- a/tap-win32/types.h
+++ b/tap-win32/types.h
@@ -86,6 +86,12 @@ typedef struct _TapExtension
   // Flags
   BOOLEAN m_TapIsRunning;
   BOOLEAN m_CalledTapDeviceFreeResources;
+
+  // DPC queue for deferred packet injection
+  BOOLEAN m_InjectDpcInitialized;
+  KDPC m_InjectDpc;
+  NDIS_SPIN_LOCK m_InjectLock;
+  Queue *m_InjectQueue;
 }
 TapExtension, *TapExtensionPointer;
 
@@ -99,6 +105,15 @@ typedef struct _TapPacket
    }
 TapPacket, *TapPacketPointer;
 
+typedef struct _InjectPacket
+   {
+#   define INJECT_PACKET_SIZE(data_size) (sizeof (InjectPacket) + (data_size))
+#   define INJECT_PACKET_FREE(ib)  NdisFreeMemory ((ib), INJECT_PACKET_SIZE ((ib)->m_Size), 0)
+    ULONG m_Size;
+    UCHAR m_Data []; // m_Data must be the last struct member
+   }
+InjectPacket, *InjectPacketPointer;
+
 typedef struct _TapAdapter
 {
 # define NAME(a) ((a)->m_NameAnsi.Buffer)