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/*++
Copyright (c) 1989-1993 Microsoft Corporation
Module Name:
loopback.c
Abstract:
This module contains the routines to implement loopback
Author:
Sanjay Anand (SanjayAn) 2/6/96
Environment:
Kernel mode
Revision History:
--*/
#include "precomp.h"
#pragma hdrstop
//
// Global lock to control access to the Loopback queue
//
DEFINE_LOCK_STRUCTURE(LoopLock)
//
// Head and tail of the Loopback queue
//
PNDIS_PACKET LoopXmitHead = (PNDIS_PACKET)NULL;
PNDIS_PACKET LoopXmitTail = (PNDIS_PACKET)NULL;
CTEEvent LoopXmitEvent;
BOOLEAN LoopXmitRtnRunning = 0;
//
// MaximumPacket sized buffer to hold the lookahead data.
//
// ZZBUGBUG: In PnP this value can change
//
// PUCHAR LookaheadBuffer=NULL;
#define LOOP_LOOKAHEAD_SIZE 128 + sizeof(IPX_HEADER) + 8 + 34
VOID
IpxDoLoopback(
IN CTEEvent *Event,
IN PVOID Context
)
/*++
Routine Description:
Does the actual loopback.
Arguments:
Event - Pointer to event structure.
Context - Pointer to ZZ
Return Value:
None.
--*/
{
PNDIS_PACKET Packet; // Pointer to packet being transmitted
PNDIS_BUFFER Buffer; // Current NDIS buffer being processed.
ULONG TotalLength; // Total length of send.
ULONG LookaheadLength; // Bytes in lookahead.
ULONG Copied; // Bytes copied so far.
PUCHAR CopyPtr; // Pointer to buffer being copied into.
PUCHAR SrcPtr; // Pointer to buffer being copied from.
ULONG SrcLength; // Length of src buffer.
BOOLEAN Rcvd = FALSE;
PIPX_SEND_RESERVED Reserved;
ULONG MacSize;
PNDIS_PACKET *PacketPtr;
UCHAR LookaheadBuffer[LOOP_LOOKAHEAD_SIZE];
IPX_DEFINE_LOCK_HANDLE(Handle)
KIRQL OldIrql;
CTEAssert(KeGetCurrentIrql() < DISPATCH_LEVEL);
//
// Raise IRQL so we can acquire locks at DPC level in the receive code.
// Also to be able to ReceiveIndicate at DPC
//
KeRaiseIrql(DISPATCH_LEVEL, &OldIrql);
IPX_GET_LOCK(&LoopLock, &Handle);
if (LoopXmitRtnRunning) {
IPX_FREE_LOCK(&LoopLock, Handle);
KeLowerIrql(OldIrql);
return;
}
LoopXmitRtnRunning = 1;
for (;;) {
//
// Get the next packet from the list.
//
Packet = LoopXmitHead;
if (Packet != (PNDIS_PACKET)NULL) {
Reserved = (PIPX_SEND_RESERVED)(Packet->ProtocolReserved);
LoopXmitHead = (PNDIS_PACKET)(Reserved->PaddingBuffer);
IPX_FREE_LOCK(&LoopLock, Handle);
} else { // Nothing left to do.
LoopXmitRtnRunning = 0;
IPX_FREE_LOCK(&LoopLock, Handle);
break;
}
//
// We use the PaddingBuffer section as the next ptr.
//
Reserved->PaddingBuffer = NULL;
IPX_DEBUG(LOOPB, ("Packet: %lx\n", Packet));
NdisQueryPacket(Packet, NULL, NULL, &Buffer, &TotalLength);
NdisQueryBuffer(Buffer, NULL, &MacSize);
IPX_DEBUG(LOOPB, ("Buffer: %lx Totalpktlen: %lx MacSize: %lx\n", Buffer, TotalLength, MacSize));
LookaheadLength = MIN(LOOP_LOOKAHEAD_SIZE, TotalLength);
Copied = 0;
CopyPtr = LookaheadBuffer;
while (Copied < LookaheadLength) {
ULONG ThisCopy; // Bytes to copy this time.
#ifdef DBG
if (!Buffer) {
DbgBreakPoint();
IPX_GET_LOCK(&LoopLock, &Handle);
LoopXmitRtnRunning = 0;
IPX_FREE_LOCK(&LoopLock, Handle);
KeLowerIrql(OldIrql);
return;
}
#endif
NdisQueryBuffer(Buffer, &SrcPtr, &SrcLength);
ThisCopy = MIN(SrcLength, LookaheadLength - Copied);
CTEMemCopy(CopyPtr, SrcPtr, ThisCopy);
Copied += ThisCopy;
CopyPtr += ThisCopy;
NdisGetNextBuffer(Buffer, &Buffer);
}
Rcvd = TRUE;
#ifdef BACK_FILL
//
// For Backfill packets, the MAC header is not yet set up; for others, it is the size
// of the first MDL (17).
//
if ((Reserved->Identifier == IDENTIFIER_IPX) &&
(Reserved->BackFill)) {
MacSize = 0;
}
#endif
IpxReceiveIndication( (NDIS_HANDLE)IPX_LOOPBACK_COOKIE, // BindingContext
Packet, // ReceiveContext
(MacSize) ? LookaheadBuffer : NULL, // HeaderBuffer
MacSize, // HeaderBufferSize
LookaheadBuffer+MacSize, // LookAheadBuffer
LookaheadLength-MacSize, // LookAheadBufferSize
TotalLength-MacSize); // PacketSize
IpxSendComplete(Context, Packet, NDIS_STATUS_SUCCESS);
//
// Give other threads a chance to run.
//
KeLowerIrql(OldIrql);
KeRaiseIrql(DISPATCH_LEVEL, &OldIrql);
IPX_GET_LOCK(&LoopLock, &Handle);
}
if (Rcvd) {
IpxReceiveComplete(Context);
}
KeLowerIrql(OldIrql);
}
VOID
IpxInitLoopback()
/*++
Routine Description:
Initializes various loopback structures.
Arguments:
Return Value:
None.
--*/
{
CTEInitLock(&LoopLock);
CTEInitEvent(&LoopXmitEvent, IpxDoLoopback);
return;
}
VOID
IpxLoopbackEnque(
IN PNDIS_PACKET Packet,
IN PVOID Context
)
/*++
Routine Description:
Enqueues a packet to the loopbackQ
Arguments:
Packet - The packet to be enqueued.
Context - Pointer to the adapter corresp to the first binding.
Return Value:
None.
--*/
{
PIPX_SEND_RESERVED Reserved = (PIPX_SEND_RESERVED)(Packet->ProtocolReserved);
IPX_DEFINE_LOCK_HANDLE(LockHandle)
//
// We use the PaddingBuffer as the next ptr.
//
Reserved->PaddingBuffer = NULL;
IPX_GET_LOCK(&LoopLock, &LockHandle);
//
// LoopbackQ is empty
//
if (LoopXmitHead == (PNDIS_PACKET)NULL) {
LoopXmitHead = Packet;
} else {
Reserved = (PIPX_SEND_RESERVED)(LoopXmitTail->ProtocolReserved);
(PNDIS_PACKET)(Reserved->PaddingBuffer) = Packet;
}
LoopXmitTail = Packet;
IPX_DEBUG(LOOPB, ("Enqued packet: %lx, Reserved: %lx\n", Packet, Reserved));
//
// If this routine is not already running, schedule it as a work item.
//
if (!LoopXmitRtnRunning) {
CTEScheduleEvent(&LoopXmitEvent, Context);
}
IPX_FREE_LOCK(&LoopLock, LockHandle);
}
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