Leaked source code of windows server 2003
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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil -*- (for GNU Emacs)
//
// Copyright (c) 1985-2000 Microsoft Corporation
//
// This file is part of the Microsoft Research IPv6 Network Protocol Stack.
// You should have received a copy of the Microsoft End-User License Agreement
// for this software along with this release; see the file "license.txt".
// If not, please see http://www.research.microsoft.com/msripv6/license.htm,
// or write to Microsoft Research, One Microsoft Way, Redmond, WA 98052-6399.
//
// Abstract:
//
// IPv6 loopback interface pseudo-driver.
//
#include "oscfg.h"
#include "ndis.h"
#include "ip6imp.h"
#include "ip6def.h"
#include "llip6if.h"
#include "route.h"
#include "icmp.h"
#include "neighbor.h"
#include "security.h"
#include <ntddip6.h>
//
// We set the default loopback MTU to be smaller than the maximum,
// to avoid the use of jumbograms. In fact, we use the ethernet MTU
// because it appears TCP behaves poorly with large MTUs.
//
#define DEFAULT_LOOPBACK_MTU 1500 // Same as ethernet.
#define MAX_LOOPBACK_MTU ((uint)-1) // Effectively infinite.
KSPIN_LOCK LoopLock;
PNDIS_PACKET LoopTransmitHead = (PNDIS_PACKET)NULL;
PNDIS_PACKET LoopTransmitTail = (PNDIS_PACKET)NULL;
WORK_QUEUE_ITEM LoopWorkItem;
int LoopTransmitRunning = 0;
Interface *LoopInterface; // Loopback interface.
//* LoopTransmit
//
// This is the work item routine called for a loopback transmit.
// Pull packets off the transmit queue and "send" them to ourselves
// by the expedient of receiving them locally.
//
void
LoopTransmit(void *Context) // Unused.
{
KIRQL OriginalIrql;
PNDIS_PACKET Packet;
IPv6Packet IPPacket;
int Rcvd = FALSE;
int PktRefs; // Packet references
UNREFERENCED_PARAMETER(Context);
ASSERT(KeGetCurrentIrql() < DISPATCH_LEVEL);
//
// All receive processing normally happens at DPC level,
// so we must pretend to be a DPC, so we raise IRQL.
// (System worker threads typically run at PASSIVE_LEVEL).
//
// Also block APCs while we're here, to make sure previous I/O requests
// issued from this thread don't block the work-item queue.
//
KeEnterCriticalRegion();
KeAcquireSpinLock(&LoopLock, &OriginalIrql);
ASSERT(LoopTransmitRunning);
for (;;) {
//
// Get the next packet from the queue.
//
Packet = LoopTransmitHead;
if (Packet == NULL)
break;
LoopTransmitHead = *(PNDIS_PACKET *)Packet->MacReserved;
KeReleaseSpinLockFromDpcLevel(&LoopLock);
Rcvd = TRUE;
//
// Prepare IPv6Packet notification info from NDIS packet.
//
InitializePacketFromNdis(&IPPacket, Packet, PC(Packet)->pc_offset);
IPPacket.NTEorIF = CastFromIF(PC(Packet)->IF);
IPPacket.Flags |= PACKET_LOOPED_BACK;
PktRefs = IPv6Receive(&IPPacket);
ASSERT(PktRefs == 0);
//
// Prevent the packet from being sent again via loopback
// from IPv6SendComplete.
//
PC(Packet)->Flags |= NDIS_FLAGS_DONT_LOOPBACK;
IPv6SendComplete(PC(Packet)->IF, Packet, IP_SUCCESS);
//
// Give other threads a chance to run.
//
KeLowerIrql(OriginalIrql);
KeAcquireSpinLock(&LoopLock, &OriginalIrql);
}
LoopTransmitRunning = FALSE;
KeReleaseSpinLockFromDpcLevel(&LoopLock);
if (Rcvd)
IPv6ReceiveComplete();
KeLowerIrql(OriginalIrql);
KeLeaveCriticalRegion();
}
//* LoopQueueTransmit
//
// This is the routine called when we need to transmit a packet to ourselves.
// We put the packet on our loopback queue, and schedule an event to deal
// with it. All the real work is done in LoopTransmit.
//
// LoopQueueTransmit is called directly from IPv6SendLL.
// It is never called via LoopInterface->Transmit.
//
void
LoopQueueTransmit(PNDIS_PACKET Packet)
{
PNDIS_PACKET *PacketPtr;
KIRQL OldIrql;
PacketPtr = (PNDIS_PACKET *)Packet->MacReserved;
*PacketPtr = (PNDIS_PACKET)NULL;
KeAcquireSpinLock(&LoopLock, &OldIrql);
//
// Add the packet to the end of the transmit queue.
//
if (LoopTransmitHead == (PNDIS_PACKET)NULL) {
// Transmit queue is empty.
LoopTransmitHead = Packet;
} else {
// Transmit queue is not empty.
PacketPtr = (PNDIS_PACKET *)LoopTransmitTail->MacReserved;
*PacketPtr = Packet;
}
LoopTransmitTail = Packet;
//
// If LoopTransmit is not already running, schedule it.
//
if (!LoopTransmitRunning) {
ExQueueWorkItem(&LoopWorkItem, DelayedWorkQueue);
LoopTransmitRunning = TRUE;
}
KeReleaseSpinLock(&LoopLock, OldIrql);
}
//* LoopbackTransmit
//
// LoopbackTransmit can be called when a multicast packet is sent
// on the loopback interface. It does nothing, because
// loopback processing actually happens in LoopTransmit.
//
void
LoopbackTransmit(
void *Context, // Pointer to loopback interface.
PNDIS_PACKET Packet, // Pointer to packet to be transmitted.
uint Offset, // Offset from start of packet to IPv6 header.
const void *LinkAddress) // Link-level address.
{
Interface *IF = (Interface *) Context;
UNREFERENCED_PARAMETER(Offset);
UNREFERENCED_PARAMETER(LinkAddress);
IPv6SendComplete(IF, Packet, IP_SUCCESS);
}
//* LoopbackConvertAddr
//
// Loopback does not use Neighbor Discovery or link-layer addresses.
//
ushort
LoopbackConvertAddr(
void *Context,
const IPv6Addr *Address,
void *LinkAddress)
{
UNREFERENCED_PARAMETER(Context);
UNREFERENCED_PARAMETER(Address);
UNREFERENCED_PARAMETER(LinkAddress);
return ND_STATE_PERMANENT;
}
//* LoopbackCreateToken
//
// Initializes the interface identifer in the address.
// For loopback, we use the interface index.
//
void
LoopbackCreateToken(void *Context, IPv6Addr *Address)
{
Interface *IF = (Interface *)Context;
*(ULONG UNALIGNED *)&Address->s6_bytes[8] = 0;
*(ULONG UNALIGNED *)&Address->s6_bytes[12] = net_long(IF->Index);
}
#pragma BEGIN_INIT
//* CreateLoopbackInterface
//
// Create a loopback interface.
//
Interface *
CreateLoopbackInterface(const char *InterfaceName)
{
GUID Guid;
LLIPv6BindInfo BindInfo;
Interface *IF;
NDIS_STATUS Status;
//
// A NULL lip_context indicates that we want to use
// the IPv6 Interface structure instead.
//
BindInfo.lip_context = NULL;
BindInfo.lip_maxmtu = MAX_LOOPBACK_MTU;
BindInfo.lip_defmtu = DEFAULT_LOOPBACK_MTU;
BindInfo.lip_flags = IF_FLAG_MULTICAST;
BindInfo.lip_type = IF_TYPE_LOOPBACK;
BindInfo.lip_hdrsize = 0;
BindInfo.lip_addrlen = 0;
BindInfo.lip_dadxmit = 0;
BindInfo.lip_pref = 0;
BindInfo.lip_addr = (uchar *)&LoopbackAddr;
BindInfo.lip_token = LoopbackCreateToken;
BindInfo.lip_rdllopt = NULL;
BindInfo.lip_wrllopt = NULL;
BindInfo.lip_cvaddr = LoopbackConvertAddr;
BindInfo.lip_setrtrlladdr = NULL;
BindInfo.lip_transmit = LoopbackTransmit;
BindInfo.lip_mclist = NULL;
BindInfo.lip_close = NULL;
BindInfo.lip_cleanup = NULL;
CreateGUIDFromName(InterfaceName, &Guid);
Status = CreateInterface(&Guid, &BindInfo, (void **)&IF);
if (Status != NDIS_STATUS_SUCCESS)
return NULL;
else
return IF;
}
//* LoopbackInit
//
// This function initializes the loopback interface.
//
// Returns FALSE if we fail to init properly.
//
int
LoopbackInit(void)
{
int rc;
//
// Prepare a work item that we will later enqueue when we want
// to execute LoopTransmit.
//
ExInitializeWorkItem(&LoopWorkItem, LoopTransmit, NULL);
KeInitializeSpinLock(&LoopLock);
//
// Create the loopback interface.
//
LoopInterface = CreateLoopbackInterface("Loopback Pseudo-Interface");
if (LoopInterface == NULL)
return FALSE;
//
// Create the usual loopback address.
//
rc = FindOrCreateNTE(LoopInterface, &LoopbackAddr,
ADDR_CONF_WELLKNOWN,
INFINITE_LIFETIME,
INFINITE_LIFETIME);
//
// Release the reference from CreateInterface.
// The interface still has a reference for itself
// by virtue of being active.
//
ReleaseIF(LoopInterface);
return rc;
}
#pragma END_INIT