Leaked source code of windows server 2003
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/*++ BUILD Version: 0009 // Increment this if a change has global effects
Copyright (c) 1987-1993 Microsoft Corporation
Module Name:
smbcemid.c
Abstract:
This module defines the routines for manipulating MIDs associated with SMB's
Author:
Balan Sethu Raman (SethuR) 26-Aug-95 Created
Notes:
--*/
#include "precomp.h"
#pragma hdrstop
#ifdef ALLOC_PRAGMA
#endif
RXDT_DefineCategory(SMBCEMID);
#define Dbg (DEBUG_TRACE_SMBCEMID)
INLINE
BOOLEAN
SmbCeVerifyMid(
PSMBCEDB_SERVER_ENTRY pServerEntry,
PSMB_EXCHANGE pExchange,
SMB_MPX_ID Mid)
{
BOOLEAN MidIsValid = TRUE;
USHORT ServerVersion;
ASSERT(pServerEntry != NULL);
ASSERT(pServerEntry->pMidAtlas != NULL);
if (pServerEntry->pMidAtlas->MaximumMidFieldWidth < 16) {
USHORT MidMask;
MidMask = 0x1 << pServerEntry->pMidAtlas->MaximumMidFieldWidth;
MidMask = MidMask -1;
MidIsValid = ((Mid & ~MidMask) == pExchange->MidCookie);
}
return MidIsValid;
}
INLINE
SMB_MPX_ID
SmbCeEncodeMid(
PSMBCEDB_SERVER_ENTRY pServerEntry,
PSMB_EXCHANGE pExchange,
SMB_MPX_ID Mid)
{
USHORT VersionNumber;
SMB_MPX_ID EncodedMid;
EncodedMid = Mid;
if (pServerEntry->pMidAtlas->MaximumMidFieldWidth < 16) {
LONG MidCookie = InterlockedIncrement(&pServerEntry->Server.MidCounter);
pExchange->MidCookie= ((USHORT)MidCookie <<
pServerEntry->pMidAtlas->MaximumMidFieldWidth);
EncodedMid |= pExchange->MidCookie;
}
return EncodedMid;
}
INLINE
SMB_MPX_ID
SmbCeExtractMid(
PSMBCEDB_SERVER_ENTRY pServerEntry,
SMB_MPX_ID EncodedMid)
{
SMB_MPX_ID Mid = EncodedMid;
if (pServerEntry->pMidAtlas->MaximumMidFieldWidth < 16) {
USHORT MidMask;
MidMask = 0x1 << pServerEntry->pMidAtlas->MaximumMidFieldWidth;
MidMask = MidMask -1;
Mid &= MidMask;
}
return Mid;
}
NTSTATUS
SmbCeAssociateExchangeWithMid(
PSMBCEDB_SERVER_ENTRY pServerEntry,
struct _SMB_EXCHANGE *pExchange)
/*++
Routine Description:
This routine associates an exchange with a MID
Arguments:
pServerEntry - the servere entry
pExchange - the Exchange instance.
Return Value:
STATUS_SUCCESS if successful, otherwise one of the following errors
Notes:
If an asynchronous mechanism to acquire MID's is to be introduced this routine
needs to be modified. Currently this routine does not return control till a
MID is acquired or the exchange is aborted/terminated.
--*/
{
NTSTATUS Status = STATUS_SUCCESS;
PSMBCEDB_REQUEST_ENTRY pRequestEntry;
SMBCE_RESUMPTION_CONTEXT ResumptionContext;
SMBCEDB_SERVER_TYPE ServerType;
BOOLEAN ResetServerEntry = FALSE;
ServerType = SmbCeGetServerType(pServerEntry);
// Acquire the resource
SmbCeAcquireSpinLock();
// Attempt to allocate a MID only for FILE Servers. Mailslot servers do
// not require a valid MID.
if (ServerType != SMBCEDB_MAILSLOT_SERVER) {
if (pServerEntry->pMidAtlas != NULL) {
if (pExchange->SmbCeFlags & SMBCE_EXCHANGE_INDEFINITE_DELAY_IN_RESPONSE) {
// This exchange response can be arbitrarily delayed. Ensure that
// all the available MIDS are not tied up in such exchanges.
if ((pServerEntry->pMidAtlas->NumberOfMidsInUse + 1) >=
pServerEntry->pMidAtlas->MaximumNumberOfMids) {
Status = STATUS_TOO_MANY_COMMANDS;
}
}
if (Status == STATUS_SUCCESS) {
if (pServerEntry->pMidAtlas->NumberOfMidsDiscarded ==
pServerEntry->pMidAtlas->MaximumNumberOfMids) {
Status = STATUS_TOO_MANY_COMMANDS;
ResetServerEntry = TRUE;
}
}
if (Status == STATUS_SUCCESS) {
SMB_MPX_ID Mid;
Status = FsRtlAssociateContextWithMid(
pServerEntry->pMidAtlas,
pExchange,
&Mid);
if (Status == STATUS_SUCCESS) {
pExchange->Mid = SmbCeEncodeMid(pServerEntry,pExchange,Mid);
}
}
} else {
if (pServerEntry->Header.State == SMBCEDB_ACTIVE) {
Status = STATUS_INVALID_PARAMETER;
} else {
Status = STATUS_CONNECTION_DISCONNECTED;
}
}
}
if (Status == STATUS_UNSUCCESSFUL) {
// Allocate a new entry and add it to the list.
pRequestEntry = (PSMBCEDB_REQUEST_ENTRY)SmbMmAllocateObject(SMBCEDB_OT_REQUEST);
if (pRequestEntry != NULL) {
// Enqueue the request entry.
SmbCeInitializeResumptionContext(&ResumptionContext);
pRequestEntry->MidRequest.Type = ACQUIRE_MID_REQUEST;
pRequestEntry->MidRequest.pExchange = pExchange;
pRequestEntry->MidRequest.pResumptionContext = &ResumptionContext;
SmbCeAddRequestEntryLite(&pServerEntry->MidAssignmentRequests,pRequestEntry);
} else {
Status = STATUS_INSUFFICIENT_RESOURCES;
}
} else if (Status == STATUS_SUCCESS) {
pExchange->SmbCeFlags |= SMBCE_EXCHANGE_MID_VALID;
}
// Release the resource
SmbCeReleaseSpinLock();
if (Status == STATUS_UNSUCCESSFUL) {
//DbgPrint("***** Thread %lx Waiting for MID Resumption Context %lx*****\n",PsGetCurrentThread(),&ResumptionContext);
SmbCeSuspend(&ResumptionContext);
Status = ResumptionContext.Status;
//DbgPrint("***** Thread %lx MID Wait Satisfied %lx *****\n",PsGetCurrentThread(),&ResumptionContext);
}
if (ResetServerEntry) {
// If all the mids have been discarded we rest the transport connection
// to start afresh.
SmbCeTransportDisconnectIndicated(pServerEntry);
}
return Status;
}
struct _SMB_EXCHANGE *
SmbCeMapMidToExchange(
PSMBCEDB_SERVER_ENTRY pServerEntry,
SMB_MPX_ID Mid)
/*++
Routine Description:
This routine maps a given MID to the exchange associated with it
Arguments:
pServerEntry - the servere entry
Mid - the mid to be mapped to an Exchange.
Return Value:
a valid SMB_EXCHANGE instance if successful, otheriwse NULL.
--*/
{
PSMB_EXCHANGE pExchange;
// Acquire the resource
SmbCeAcquireSpinLock();
if (pServerEntry->pMidAtlas != NULL) {
pExchange = FsRtlMapMidToContext(
pServerEntry->pMidAtlas,
Mid);
if (pExchange != NULL) {
if (!SmbCeVerifyMid(pServerEntry,pExchange,Mid)) {
pExchange = NULL;
}
}
} else {
pExchange = NULL;
}
// Release the resource
SmbCeReleaseSpinLock();
return pExchange;
}
NTSTATUS
SmbCeDissociateMidFromExchange(
PSMBCEDB_SERVER_ENTRY pServerEntry,
struct _SMB_EXCHANGE *pExchange)
/*++
Routine Description:
This routine disassociates an exchange from the MID
Arguments:
pServerEntry - the servere entry
pExchange - the exchange instance.
Return Value:
a valid SMB_EXCHANGE instance if successful, otheriwse NULL.
Notes:
If an asynchronous mechanism to acquire MID's is to be introduced this routine
needs to be modified. This modification will also include posting requests
for resumption of exchanges when invoked at DPC level.
--*/
{
NTSTATUS Status = RX_MAP_STATUS(SUCCESS);
SMBCEDB_SERVER_TYPE ServerType;
ServerType = SmbCeGetServerType(pServerEntry);
if ((ServerType != SMBCEDB_MAILSLOT_SERVER) &&
(pExchange->Mid != SMBCE_OPLOCK_RESPONSE_MID) &&
(pExchange->Mid != SMBCE_MAILSLOT_OPERATION_MID)) {
PVOID pContext;
PSMBCEDB_REQUEST_ENTRY pRequestEntry = NULL;
// Acquire the resource
SmbCeAcquireSpinLock();
if (pExchange->SmbCeFlags & SMBCE_EXCHANGE_MID_VALID) {
// Check if there are any pending MID assignment requests and transfer the MID
// if one exists.
pRequestEntry = SmbCeGetFirstRequestEntry(&pServerEntry->MidAssignmentRequests);
if (pRequestEntry != NULL) {
SmbCeRemoveRequestEntryLite(&pServerEntry->MidAssignmentRequests,pRequestEntry);
}
if (pServerEntry->pMidAtlas != NULL) {
SMB_MPX_ID Mid;
Mid = SmbCeExtractMid(pServerEntry,pExchange->Mid);
if (pRequestEntry != NULL) {
Status = FsRtlReassociateMid(
pServerEntry->pMidAtlas,
Mid,
pRequestEntry->MidRequest.pExchange);
ASSERT(Status == STATUS_SUCCESS);
pRequestEntry->MidRequest.pExchange->SmbCeFlags |= SMBCE_EXCHANGE_MID_VALID;
pRequestEntry->MidRequest.pExchange->Mid = SmbCeEncodeMid(
pServerEntry,
pRequestEntry->MidRequest.pExchange,
Mid);
pRequestEntry->MidRequest.pResumptionContext->Status = STATUS_SUCCESS;
} else {
Status = FsRtlMapAndDissociateMidFromContext(
pServerEntry->pMidAtlas,
Mid,
&pContext);
ASSERT(pContext == pExchange);
}
} else {
Status = STATUS_INVALID_PARAMETER;
}
}
// Release the resource
SmbCeReleaseSpinLock();
if (pRequestEntry != NULL) {
// Signal the waiter for resumption
SmbCeResume(pRequestEntry->MidRequest.pResumptionContext);
SmbCeTearDownRequestEntry(pRequestEntry);
}
}
pExchange->SmbCeFlags &= ~SMBCE_EXCHANGE_MID_VALID;
return Status;
}
VOID
SmbCeDiscardMidAssignmentRequests(
PSMBCEDB_SERVER_ENTRY pServerEntry)
/*++
Routine Description:
This routine discards all mid assignment requests for a given server entry
Arguments:
pServerEntry - the servere entry
Notes:
This typically happens when the mids in use are being cancelled against a
down level server. In such cases there is no cancel command that can be
sent to the server. Typically we throw away the MID and not use it any
further. this will lead to a graceful degradation in performance when
the connection is reestablished
--*/
{
SMBCEDB_REQUESTS MidRequests;
InitializeListHead(&MidRequests.ListHead);
SmbCeAcquireSpinLock();
if (pServerEntry->pMidAtlas != NULL) {
if (pServerEntry->pMidAtlas->NumberOfMidsDiscarded ==
pServerEntry->pMidAtlas->MaximumNumberOfMids) {
SmbCeTransferRequests(
&MidRequests,
&pServerEntry->MidAssignmentRequests);
}
}
SmbCeReleaseSpinLock();
SmbCeResumeDiscardedMidAssignmentRequests(
&MidRequests,
STATUS_TOO_MANY_COMMANDS);
SmbCeDereferenceServerEntry(pServerEntry);
}
NTSTATUS
SmbCepDiscardMidAssociatedWithExchange(
PSMB_EXCHANGE pExchange)
/*++
Routine Description:
This routine discards the mid associated with an exchange
Arguments:
pExchange - the exchange
Notes:
We use the hypercritical thread to ensure that this request does not block
behind other requests.
This routine also assumes that it is invoked with the SmbCeSpinLock held
--*/
{
NTSTATUS Status = STATUS_SUCCESS;
if ((pExchange->SmbCeFlags & SMBCE_EXCHANGE_MID_VALID) &&
(pExchange->Mid != SMBCE_OPLOCK_RESPONSE_MID) &&
(pExchange->Mid != SMBCE_MAILSLOT_OPERATION_MID) &&
(pExchange->Mid != SMBCE_ECHO_PROBE_MID)) {
PSMBCEDB_SERVER_ENTRY pServerEntry;
pServerEntry = SmbCeGetExchangeServerEntry(pExchange);
if ((pServerEntry != NULL) &&
(pServerEntry->pMidAtlas != NULL)) {
SMB_MPX_ID Mid;
Mid = SmbCeExtractMid(pServerEntry,pExchange->Mid);
Status = FsRtlReassociateMid(
pServerEntry->pMidAtlas,
Mid,
NULL);
if (Status == STATUS_SUCCESS) {
pServerEntry->pMidAtlas->NumberOfMidsDiscarded++;
if (pServerEntry->pMidAtlas->NumberOfMidsDiscarded ==
pServerEntry->pMidAtlas->MaximumNumberOfMids) {
// All the mids have been discarded. Any pending
// mid assignment requests needs to be completed
// with the appropriate error code.
SmbCeReferenceServerEntry(pServerEntry);
Status = RxDispatchToWorkerThread(
MRxSmbDeviceObject,
HyperCriticalWorkQueue,
SmbCeDiscardMidAssignmentRequests,
pServerEntry);
}
}
pExchange->SmbCeFlags &= ~SMBCE_EXCHANGE_MID_VALID;
} else {
Status = STATUS_INVALID_PARAMETER;
}
}
return Status;
}
VOID
SmbCeResumeDiscardedMidAssignmentRequests(
PSMBCEDB_REQUESTS pMidRequests,
NTSTATUS ResumptionStatus)
/*++
Routine Description:
This routine resumes discarded mid assignment requests with the appropriate error
Arguments:
pMidRequests - the discarded requests
ResumptionStatus - the resumption status
Return Value:
a valid SMB_EXCHANGE instance if successful, otheriwse NULL.
Notes:
This routine and the routines that follow enable a pipelined reuse of MID's
If a large buffer is to be copied then this can be done without hodling onto
a MID. This improves the throughput between the client and the server. At the
very least this mechanism ensures that the connection engine will not be the
constraining factor in MID reuse.
--*/
{
PSMBCEDB_REQUEST_ENTRY pRequestEntry;
pRequestEntry = SmbCeGetFirstRequestEntry(pMidRequests);
while (pRequestEntry != NULL) {
// Remove the request entry from the list
SmbCeRemoveRequestEntryLite(pMidRequests,pRequestEntry);
ASSERT(pRequestEntry->GenericRequest.Type == ACQUIRE_MID_REQUEST);
// Signal the waiter for resumption
pRequestEntry->MidRequest.pResumptionContext->Status = ResumptionStatus;
SmbCeResume(pRequestEntry->MidRequest.pResumptionContext);
SmbCeTearDownRequestEntry(pRequestEntry);
pRequestEntry = SmbCeGetFirstRequestEntry(pMidRequests);
}
}
struct _SMB_EXCHANGE *
SmbCeGetExchangeAssociatedWithBuffer(
PSMBCEDB_SERVER_ENTRY pServerEntry,
PVOID pBuffer)
/*++
Routine Description:
This routine gets the exchange associated with a buffer
Arguments:
pServerEntry - the servere entry
pBuffer - the buffer instance.
Return Value:
a valid SMB_EXCHANGE instance if successful, otheriwse NULL.
Notes:
This routine and the routines that follow enable a pipelined reuse of MID's
If a large buffer is to be copied then this can be done without hodling onto
a MID. This improves the throughput between the client and the server. At the
very least this mechanism ensures that the connection engine will not be the
constraining factor in MID reuse.
--*/
{
PSMBCEDB_REQUEST_ENTRY pRequestEntry;
PSMB_EXCHANGE pExchange = NULL;
// Acquire the resource
SmbCeAcquireSpinLock();
// Walk through the list of requests maintained on this and remove the one
// matching the cached buffer ptr with the ptr indicated
pRequestEntry = SmbCeGetFirstRequestEntry(&pServerEntry->OutstandingRequests);
while (pRequestEntry != NULL) {
if ((pRequestEntry->GenericRequest.Type == COPY_DATA_REQUEST) &&
(pRequestEntry->CopyDataRequest.pBuffer == pBuffer)) {
pExchange = pRequestEntry->CopyDataRequest.pExchange;
pRequestEntry->CopyDataRequest.pBuffer = NULL;
break;
}
pRequestEntry = SmbCeGetNextRequestEntry(
&pServerEntry->OutstandingRequests,
pRequestEntry);
}
// Release the resource
SmbCeReleaseSpinLock();
return pExchange;
}
NTSTATUS
SmbCeAssociateBufferWithExchange(
PSMBCEDB_SERVER_ENTRY pServerEntry,
struct _SMB_EXCHANGE * pExchange,
PVOID pBuffer)
/*++
Routine Description:
This routine establishes an association between an exchange and a copy data request
buffer
Arguments:
pServerEntry - the servere entry
pBuffer - the buffer instance.
Return Value:
STATUS_SUCCESS if succesful
--*/
{
NTSTATUS Status = STATUS_SUCCESS;
PSMBCEDB_REQUEST_ENTRY pRequestEntry;
// Acquire the resource
SmbCeAcquireSpinLock();
Status = pServerEntry->ServerStatus;
if (Status == RX_MAP_STATUS(SUCCESS)) {
// Walk through the list of requests maintained on this and remove the one
// matching the cached buffer ptr with the ptr indicated
pRequestEntry = SmbCeGetFirstRequestEntry(&pServerEntry->OutstandingRequests);
while (pRequestEntry != NULL) {
if ((pRequestEntry->GenericRequest.Type == COPY_DATA_REQUEST) &&
(pRequestEntry->CopyDataRequest.pBuffer == NULL)) {
pRequestEntry->CopyDataRequest.pExchange = pExchange;
pRequestEntry->CopyDataRequest.pBuffer = pBuffer;
break;
}
pRequestEntry = SmbCeGetNextRequestEntry(&pServerEntry->OutstandingRequests,pRequestEntry);
}
}
// Release the resource
SmbCeReleaseSpinLock();
if ((Status == RX_MAP_STATUS(SUCCESS)) &&
(pRequestEntry == NULL)) {
// Allocate a new entry and add it to the list.
pRequestEntry = (PSMBCEDB_REQUEST_ENTRY)SmbMmAllocateObject(SMBCEDB_OT_REQUEST);
if (pRequestEntry != NULL) {
// Enqueue the request entry.
pRequestEntry->CopyDataRequest.Type = COPY_DATA_REQUEST;
pRequestEntry->CopyDataRequest.pExchange = pExchange;
pRequestEntry->CopyDataRequest.pBuffer = pBuffer;
// Acquire the resource
SmbCeAcquireSpinLock();
if ((Status = pServerEntry->ServerStatus) == RX_MAP_STATUS(SUCCESS)) {
SmbCeAddRequestEntryLite(&pServerEntry->OutstandingRequests,pRequestEntry);
}
// Release the resource
SmbCeReleaseSpinLock();
if (Status != RX_MAP_STATUS(SUCCESS)) {
SmbCeTearDownRequestEntry(pRequestEntry);
}
} else {
Status = STATUS_INSUFFICIENT_RESOURCES;
}
}
return Status;
}
VOID
SmbCePurgeBuffersAssociatedWithExchange(
PSMBCEDB_SERVER_ENTRY pServerEntry,
struct _SMB_EXCHANGE * pExchange)
/*++
Routine Description:
This routine purges all the copy data requests associated with an exchange.
Arguments:
pServerEntry - the servere entry
pExchange - the exchange instance.
Notes:
This mechanism of delaying the purging of requests associated with an exchange
till it is discared is intended to solve the problem of repeated allocation/freeing
of request entries. This rests on the assumption that there will not be too many
copy data requests outstanding for any exchange. If evidence to the contrary is
noticed this technique has to be modified.
--*/
{
SMBCEDB_REQUESTS ExchangeRequests;
PSMBCEDB_REQUEST_ENTRY pRequestEntry;
PSMBCEDB_REQUEST_ENTRY pNextRequestEntry;
SmbCeInitializeRequests(&ExchangeRequests);
// Acquire the resource
SmbCeAcquireSpinLock();
// Walk through the list of requests maintained on this and remove the one
// matching the given exchange
pRequestEntry = SmbCeGetFirstRequestEntry(&pServerEntry->OutstandingRequests);
while (pRequestEntry != NULL) {
pNextRequestEntry = SmbCeGetNextRequestEntry(&pServerEntry->OutstandingRequests,pRequestEntry);
if (pRequestEntry->GenericRequest.pExchange == pExchange) {
SmbCeRemoveRequestEntryLite(&pServerEntry->OutStandingRequests,pRequestEntry);
SmbCeAddRequestEntryLite(&ExchangeRequests,pRequestEntry);
}
pRequestEntry = pNextRequestEntry;
}
// Release the resource
SmbCeReleaseSpinLock();
pRequestEntry = SmbCeGetFirstRequestEntry(&ExchangeRequests);
while (pRequestEntry != NULL) {
SmbCeRemoveRequestEntryLite(&ExchangeRequests,pRequestEntry);
SmbCeTearDownRequestEntry(pRequestEntry);
pRequestEntry = SmbCeGetFirstRequestEntry(&ExchangeRequests);
}
}