[cgutman] 42578: - Rewrite most of the loopback code - The new code is faster, uses less memory, and is less complex than the previous code - Add a NULL check to fix a potential crash

Author: cgutman
Date: Mon Aug 10 05:27:39 2009
New Revision: 42578

URL: http://svn.reactos.org/svn/reactos?rev=42578&view=rev
Log:
 - Rewrite most of the loopback code
 - The new code is faster, uses less memory, and is less complex than the previous code
 - Add a NULL check to fix a potential crash

Modified:
    trunk/reactos/lib/drivers/ip/network/loopback.c

Modified: trunk/reactos/lib/drivers/ip/network/loopback.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/lib/drivers/ip/network/loo…
==============================================================================
--- trunk/reactos/lib/drivers/ip/network/loopback.c [iso-8859-1] (original)
+++ trunk/reactos/lib/drivers/ip/network/loopback.c [iso-8859-1] Mon Aug 10 05:27:39 2009
@@ -11,118 +11,6 @@
 #include "precomp.h"
 
 PIP_INTERFACE Loopback = NULL;
-typedef struct _LAN_WQ_ITEM {
-    LIST_ENTRY ListEntry;
-    PNDIS_PACKET Packet;
-    PLAN_ADAPTER Adapter;
-    UINT BytesTransferred;
-} LAN_WQ_ITEM, *PLAN_WQ_ITEM;
-
-/* Work around being called back into afd at Dpc level */
-KSPIN_LOCK LoopWorkLock;
-LIST_ENTRY LoopWorkList;
-WORK_QUEUE_ITEM LoopWorkItem;
-BOOLEAN LoopReceiveWorkerBusy = FALSE;
-
-VOID NTAPI LoopReceiveWorker( PVOID Context ) {
-    PLIST_ENTRY ListEntry;
-    PLAN_WQ_ITEM WorkItem;
-    PNDIS_PACKET Packet;
-    PLAN_ADAPTER Adapter;
-    UINT BytesTransferred;
-    PNDIS_BUFFER NdisBuffer;
-    IP_PACKET IPPacket;
-	KIRQL OldIrql;
-
-    TI_DbgPrint(DEBUG_DATALINK, ("Called.\n"));
-
-	TcpipAcquireSpinLock( &LoopWorkLock, &OldIrql );
-    while( !IsListEmpty(&LoopWorkList) )
-    {
-		ListEntry = RemoveHeadList( &LoopWorkList );
-		TcpipReleaseSpinLock( &LoopWorkLock, OldIrql );
-
-		WorkItem = CONTAINING_RECORD(ListEntry, LAN_WQ_ITEM, ListEntry);
-		
-		TI_DbgPrint(DEBUG_DATALINK, ("WorkItem: %x\n", WorkItem));
-		
-		Packet = WorkItem->Packet;
-		Adapter = WorkItem->Adapter;
-		BytesTransferred = WorkItem->BytesTransferred;
-		
-		exFreePool( WorkItem );
-
-        IPInitializePacket(&IPPacket, 0);
-		
-        IPPacket.NdisPacket = Packet;
-		
-        TI_DbgPrint(DEBUG_DATALINK, ("Packet %x Adapter %x Trans %x\n",
-                                     Packet, Adapter, BytesTransferred));
-		
-        NdisGetFirstBufferFromPacket(Packet,
-                                     &NdisBuffer,
-                                     &IPPacket.Header,
-                                     &IPPacket.ContigSize,
-                                     &IPPacket.TotalSize);
-
-		IPPacket.ContigSize = IPPacket.TotalSize = BytesTransferred;
-        /* Determine which upper layer protocol that should receive
-           this packet and pass it to the correct receive handler */
-		
-		TI_DbgPrint
-			(MID_TRACE,
-			 ("ContigSize: %d, TotalSize: %d, BytesTransferred: %d\n",
-			  IPPacket.ContigSize, IPPacket.TotalSize,
-			  BytesTransferred));
-		
-		IPPacket.Position = 0;
-		
-        IPReceive(Loopback, &IPPacket);
-		
-		FreeNdisPacket( Packet );
-		TcpipAcquireSpinLock( &LoopWorkLock, &OldIrql );
-    }
-    TI_DbgPrint(DEBUG_DATALINK, ("Leaving\n"));
-    LoopReceiveWorkerBusy = FALSE;
-	TcpipReleaseSpinLock( &LoopWorkLock, OldIrql );
-}
-
-VOID LoopSubmitReceiveWork(
-    NDIS_HANDLE BindingContext,
-    PNDIS_PACKET Packet,
-    NDIS_STATUS Status,
-    UINT BytesTransferred) {
-    PLAN_WQ_ITEM WQItem;
-    PLAN_ADAPTER Adapter = (PLAN_ADAPTER)BindingContext;
-    KIRQL OldIrql;
-
-    TcpipAcquireSpinLock( &LoopWorkLock, &OldIrql );
-
-    WQItem = exAllocatePool( NonPagedPool, sizeof(LAN_WQ_ITEM) );
-    if( !WQItem ) {
-	TcpipReleaseSpinLock( &LoopWorkLock, OldIrql );
-	return;
-    }
-
-    WQItem->Packet = Packet;
-    WQItem->Adapter = Adapter;
-    WQItem->BytesTransferred = BytesTransferred;
-    InsertTailList( &LoopWorkList, &WQItem->ListEntry );
-
-    TI_DbgPrint(DEBUG_DATALINK, ("Packet %x Adapter %x BytesTrans %x\n",
-                                 Packet, Adapter, BytesTransferred));
-
-    if( !LoopReceiveWorkerBusy ) {
-	LoopReceiveWorkerBusy = TRUE;
-	ExQueueWorkItem( &LoopWorkItem, CriticalWorkQueue );
-	TI_DbgPrint(DEBUG_DATALINK,
-		    ("Work item inserted %x %x\n", &LoopWorkItem, WQItem));
-    } else {
-        TI_DbgPrint(DEBUG_DATALINK,
-                    ("LOOP WORKER BUSY %x %x\n", &LoopWorkItem, WQItem));
-    }
-    TcpipReleaseSpinLock( &LoopWorkLock, OldIrql );
-}
 
 VOID LoopTransmit(
   PVOID Context,
@@ -144,6 +32,8 @@
     UINT PacketLength;
     PNDIS_PACKET XmitPacket;
     NDIS_STATUS NdisStatus;
+    IP_PACKET IPPacket;
+    PNDIS_BUFFER NdisBuffer;
 
     ASSERT_KM_POINTER(NdisPacket);
     ASSERT_KM_POINTER(PC(NdisPacket));
@@ -156,13 +46,24 @@
     NdisStatus = AllocatePacketWithBuffer
         ( &XmitPacket, PacketBuffer, PacketLength );
 
+    (PC(NdisPacket)->DLComplete)
+        ( PC(NdisPacket)->Context, NdisPacket, NdisStatus );
+
     if( NT_SUCCESS(NdisStatus) ) {
-        LoopSubmitReceiveWork
-            ( NULL, XmitPacket, STATUS_SUCCESS, PacketLength );
+        IPInitializePacket(&IPPacket, 0);
+		
+        IPPacket.NdisPacket = XmitPacket;
+		
+        NdisGetFirstBufferFromPacket(XmitPacket,
+                                     &NdisBuffer,
+                                     &IPPacket.Header,
+                                     &IPPacket.ContigSize,
+                                     &IPPacket.TotalSize);
+
+        IPReceive(Loopback, &IPPacket);
+
+        FreeNdisPacket(XmitPacket);
     }
-
-    (PC(NdisPacket)->DLComplete)
-        ( PC(NdisPacket)->Context, NdisPacket, STATUS_SUCCESS );
 
     TI_DbgPrint(MAX_TRACE, ("Done\n"));
 }
@@ -179,15 +80,9 @@
  *   Status of operation
  */
 {
-  NDIS_STATUS Status;
   LLIP_BIND_INFO BindInfo;
 
-  Status = NDIS_STATUS_SUCCESS;
-
   TI_DbgPrint(MID_TRACE, ("Called.\n"));
-
-  InitializeListHead( &LoopWorkList );
-  ExInitializeWorkItem( &LoopWorkItem, LoopReceiveWorker, NULL );
 
   /* Bind the adapter to network (IP) layer */
   BindInfo.Context = NULL;
@@ -199,6 +94,7 @@
   BindInfo.Transmit = LoopTransmit;
 
   Loopback = IPCreateInterface(&BindInfo);
+  if (!Loopback) return NDIS_STATUS_RESOURCES;
 
   Loopback->Name.Buffer = L"Loopback";
   Loopback->Name.MaximumLength = Loopback->Name.Length =
@@ -213,7 +109,7 @@
 
   TI_DbgPrint(MAX_TRACE, ("Leaving.\n"));
 
-  return Status;
+  return NDIS_STATUS_SUCCESS;
 }