dlls/dplayx/name_server.c - wine - Git at Google

 /* DPLAYX.DLL name server implementation
  *
  * Copyright 2000-2001 - Peter Hunnisett
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */

 /* NOTE: Methods with the NS_ prefix are name server methods */

 #include <stdarg.h>
 #include <string.h>

 #define NONAMELESSUNION
 #define NONAMELESSSTRUCT
 #include "windef.h"
 #include "winbase.h"
 #include "winnls.h"
 #include "wine/unicode.h"
 #include "wine/debug.h"
 #include "mmsystem.h"

 #include "dplayx_global.h"
 #include "name_server.h"
 #include "wine/dplaysp.h"
 #include "dplayx_messages.h"
 #include "dplayx_queue.h"

 /* FIXME: Need to create a crit section, store and use it */

 WINE_DEFAULT_DEBUG_CHANNEL(dplay);

 /* NS specific structures */
 struct NSCacheData
 {
   DPQ_ENTRY(NSCacheData) next;

   DWORD dwTime; /* Time at which data was last known valid */
   LPDPSESSIONDESC2 data;

   LPVOID lpNSAddrHdr;

 };
 typedef struct NSCacheData NSCacheData, *lpNSCacheData;

 struct NSCache
 {
   lpNSCacheData present; /* keep track of what is to be looked at when walking */

   DPQ_HEAD(NSCacheData) first;

   BOOL bNsIsLocal;
   LPVOID lpLocalAddrHdr;  /* FIXME: Not yet used */
   LPVOID lpRemoteAddrHdr; /* FIXME: Not yet used */
 };
 typedef struct NSCache NSCache, *lpNSCache;

 /* Function prototypes */
 static DPQ_DECL_DELETECB( cbDeleteNSNodeFromHeap, lpNSCacheData );

 /* Name Server functions
  * ---------------------
  */
 void NS_SetLocalComputerAsNameServer( LPCDPSESSIONDESC2 lpsd, LPVOID lpNSInfo )
 {
   lpNSCache lpCache = (lpNSCache)lpNSInfo;

   lpCache->bNsIsLocal = TRUE;
 }

 static DPQ_DECL_COMPARECB( cbUglyPig, GUID )
 {
   return IsEqualGUID( elem1, elem2 );
 }

 /* Store the given NS remote address for future reference */
 void NS_AddRemoteComputerAsNameServer( LPCVOID                      lpcNSAddrHdr,
                                        DWORD                        dwHdrSize,
                                        LPCDPMSG_ENUMSESSIONSREPLY   lpcMsg,
                                        LPVOID                       lpNSInfo )
 {
   DWORD len;
   lpNSCache     lpCache = (lpNSCache)lpNSInfo;
   lpNSCacheData lpCacheNode;

   TRACE( "%p, %p, %p\n", lpcNSAddrHdr, lpcMsg, lpNSInfo );

   /* See if we can find this session. If we can, remove it as it's a dup */
   DPQ_REMOVE_ENTRY_CB( lpCache->first, next, data->guidInstance, cbUglyPig,
                        lpcMsg->sd.guidInstance, lpCacheNode );

   if( lpCacheNode != NULL )
   {
     TRACE( "Duplicate session entry for %s removed - updated version kept\n",
            debugstr_guid( &lpCacheNode->data->guidInstance ) );
     cbDeleteNSNodeFromHeap( lpCacheNode );
   }

   /* Add this to the list */
   lpCacheNode = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof( *lpCacheNode ) );

   if( lpCacheNode == NULL )
   {
     ERR( "no memory for NS node\n" );
     return;
   }

   lpCacheNode->lpNSAddrHdr = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY,
                                         dwHdrSize );
   CopyMemory( lpCacheNode->lpNSAddrHdr, lpcNSAddrHdr, dwHdrSize );

   lpCacheNode->data = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof( *(lpCacheNode->data) ) );

   if( lpCacheNode->data == NULL )
   {
     ERR( "no memory for SESSIONDESC2\n" );
     HeapFree( GetProcessHeap(), 0, lpCacheNode );
     return;
   }

   *lpCacheNode->data = lpcMsg->sd;
   len = WideCharToMultiByte( CP_ACP, 0, (LPCWSTR)(lpcMsg+1), -1, NULL, 0, NULL, NULL );
   if ((lpCacheNode->data->u1.lpszSessionNameA = HeapAlloc( GetProcessHeap(), 0, len )))
   {
       WideCharToMultiByte( CP_ACP, 0, (LPCWSTR)(lpcMsg+1), -1,
                            lpCacheNode->data->u1.lpszSessionNameA, len, NULL, NULL );
   }

   lpCacheNode->dwTime = timeGetTime();

   DPQ_INSERT(lpCache->first, lpCacheNode, next );

   lpCache->present = lpCacheNode;

   /* Use this message as an opportunity to weed out any old sessions so
    * that we don't enum them again
    */
   NS_PruneSessionCache( lpNSInfo );
 }

 LPVOID NS_GetNSAddr( LPVOID lpNSInfo )
 {
   lpNSCache lpCache = (lpNSCache)lpNSInfo;

   FIXME( ":quick stub\n" );

   /* Ok. Cheat and don't search for the correct stuff just take the first.
    * FIXME: In the future how are we to know what is _THE_ enum we used?
    *        This is going to have to go into dplay somehow. Perhaps it
    *        comes back with app server id for the join command! Oh... that
    *        must be it. That would make this method obsolete once that's
    *        in place.
    */
 #if 1
   return lpCache->first.lpQHFirst->lpNSAddrHdr;
 #else
   /* FIXME: Should convert over to this */
   return lpCache->bNsIsLocal ? lpCache->lpLocalAddrHdr
                              : lpCache->lpRemoteAddrHdr;
 #endif
 }

 /* Get the magic number associated with the Name Server */
 DWORD NS_GetNsMagic( LPVOID lpNSInfo )
 {
   LPDWORD lpHdrInfo = NS_GetNSAddr( lpNSInfo );

   return lpHdrInfo[1];
 }

 void NS_SetLocalAddr( LPVOID lpNSInfo, LPCVOID lpHdr, DWORD dwHdrSize )
 {
   lpNSCache lpCache = (lpNSCache)lpNSInfo;

   lpCache->lpLocalAddrHdr = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, dwHdrSize );

   CopyMemory( lpCache->lpLocalAddrHdr, lpHdr, dwHdrSize );
 }

 /* This function is responsible for sending a request for all other known
    nameservers to send us what sessions they have registered locally
  */
 HRESULT NS_SendSessionRequestBroadcast( LPCGUID lpcGuid,
                                         DWORD dwFlags,
                                         const SPINITDATA *lpSpData )

 {
   DPSP_ENUMSESSIONSDATA data;
   LPDPMSG_ENUMSESSIONSREQUEST lpMsg;

   TRACE( "enumerating for guid %s\n", debugstr_guid( lpcGuid ) );

   /* Get the SP to deal with sending the EnumSessions request */
   FIXME( ": not all data fields are correct\n" );

   data.dwMessageSize = lpSpData->dwSPHeaderSize + sizeof( *lpMsg ); /*FIXME!*/
   data.lpMessage = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY,
                               data.dwMessageSize );
   data.lpISP = lpSpData->lpISP;
   data.bReturnStatus = (dwFlags & DPENUMSESSIONS_RETURNSTATUS) ? TRUE : FALSE;


   lpMsg = (LPDPMSG_ENUMSESSIONSREQUEST)(((BYTE*)data.lpMessage)+lpSpData->dwSPHeaderSize);

   /* Setup EnumSession request message */
   lpMsg->envelope.dwMagic    = DPMSGMAGIC_DPLAYMSG;
   lpMsg->envelope.wCommandId = DPMSGCMD_ENUMSESSIONSREQUEST;
   lpMsg->envelope.wVersion   = DPMSGVER_DP6;

   lpMsg->dwPasswordSize = 0; /* FIXME: If enumerating passwords..? */
   lpMsg->dwFlags        = dwFlags;

   lpMsg->guidApplication = *lpcGuid;

   return (lpSpData->lpCB->EnumSessions)( &data );
 }

 /* Delete a name server node which has been allocated on the heap */
 static DPQ_DECL_DELETECB( cbDeleteNSNodeFromHeap, lpNSCacheData )
 {
   /* NOTE: This proc doesn't deal with the walking pointer */

   /* FIXME: Memory leak on data (contained ptrs) */
   HeapFree( GetProcessHeap(), 0, elem->data );
   HeapFree( GetProcessHeap(), 0, elem->lpNSAddrHdr );
   HeapFree( GetProcessHeap(), 0, elem );
 }

 /* Render all data in a session cache invalid */
 void NS_InvalidateSessionCache( LPVOID lpNSInfo )
 {
   lpNSCache lpCache = (lpNSCache)lpNSInfo;

   if( lpCache == NULL )
   {
     ERR( ": invalidate nonexistent cache\n" );
     return;
   }

   DPQ_DELETEQ( lpCache->first, next, lpNSCacheData, cbDeleteNSNodeFromHeap );

   /* NULL out the walking pointer */
   lpCache->present = NULL;

   lpCache->bNsIsLocal = FALSE;

 }

 /* Create and initialize a session cache */
 BOOL NS_InitializeSessionCache( LPVOID* lplpNSInfo )
 {
   lpNSCache lpCache = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof( *lpCache ) );

   *lplpNSInfo = lpCache;

   if( lpCache == NULL )
   {
     return FALSE;
   }

   DPQ_INIT(lpCache->first);
   lpCache->present = NULL;

   lpCache->bNsIsLocal = FALSE;

   return TRUE;
 }

 /* Delete a session cache */
 void NS_DeleteSessionCache( LPVOID lpNSInfo )
 {
   NS_InvalidateSessionCache( (lpNSCache)lpNSInfo );
 }

 /* Reinitialize the present pointer for this cache */
 void NS_ResetSessionEnumeration( LPVOID lpNSInfo )
 {
   ((lpNSCache)lpNSInfo)->present = ((lpNSCache)lpNSInfo)->first.lpQHFirst;
 }

 LPDPSESSIONDESC2 NS_WalkSessions( LPVOID lpNSInfo )
 {
   LPDPSESSIONDESC2 lpSessionDesc;
   lpNSCache lpCache = (lpNSCache)lpNSInfo;

   /* FIXME: The pointers could disappear when walking if a prune happens */

   /* Test for end of the list */
   if( lpCache->present == NULL )
   {
     return NULL;
   }

   lpSessionDesc = lpCache->present->data;

   /* Advance tracking pointer */
   lpCache->present = lpCache->present->next.lpQNext;

   return lpSessionDesc;
 }

 /* This method should check to see if there are any sessions which are
  * older than the criteria. If so, just delete that information.
  */
 /* FIXME: This needs to be called by some periodic timer */
 void NS_PruneSessionCache( LPVOID lpNSInfo )
 {
   lpNSCache     lpCache = lpNSInfo;

   const DWORD dwPresentTime = timeGetTime();
   const DWORD dwPrunePeriod = DPMSG_WAIT_60_SECS; /* is 60 secs enough? */

   /* This silly little algorithm is based on the fact we keep entries in
    * the queue in a time based order. It also assumes that it is not possible
    * to wrap around over yourself (which is not unreasonable).
    * The if statements verify if the first entry in the queue is less
    * than dwPrunePeriod old depending on the "clock" roll over.
    */
   for( ;; )
   {
     lpNSCacheData lpFirstData;

     if( DPQ_IS_EMPTY(lpCache->first) )
     {
       /* Nothing to prune */
       break;
     }

     /* Deal with time in a wrap around safe manner - unsigned arithmetic.
      * Check the difference in time */
     if( (dwPresentTime - (DPQ_FIRST(lpCache->first)->dwTime)) < dwPrunePeriod )
     {
       /* First entry has not expired yet; don't prune */
       break;
     }

     lpFirstData = DPQ_FIRST(lpCache->first);
     DPQ_REMOVE( lpCache->first, DPQ_FIRST(lpCache->first), next );
     cbDeleteNSNodeFromHeap( lpFirstData );
   }

 }

 /* NAME SERVER Message stuff */
 void NS_ReplyToEnumSessionsRequest( LPCVOID lpcMsg,
                                     LPVOID* lplpReplyData,
                                     LPDWORD lpdwReplySize,
                                     IDirectPlay2Impl* lpDP )
 {
   LPDPMSG_ENUMSESSIONSREPLY rmsg;
   DWORD dwVariableSize;
   DWORD dwVariableLen;
   /* LPCDPMSG_ENUMSESSIONSREQUEST msg = (LPDPMSG_ENUMSESSIONSREQUEST)lpcMsg; */
   BOOL bAnsi = TRUE; /* FIXME: This needs to be in the DPLAY interface */

   FIXME( ": few fixed + need to check request for response\n" );

   if (bAnsi)
   {
       dwVariableLen = MultiByteToWideChar( CP_ACP, 0,
                                            lpDP->dp2->lpSessionDesc->u1.lpszSessionNameA,
                                            -1, NULL, 0 );
   }
   else
   {
       dwVariableLen = strlenW( lpDP->dp2->lpSessionDesc->u1.lpszSessionName ) + 1;
   }

   dwVariableSize = dwVariableLen * sizeof( WCHAR );

   *lpdwReplySize = lpDP->dp2->spData.dwSPHeaderSize +
                      sizeof( *rmsg ) + dwVariableSize;
   *lplpReplyData = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY,
                               *lpdwReplySize );

   rmsg = (LPDPMSG_ENUMSESSIONSREPLY)( (BYTE*)*lplpReplyData +
                                              lpDP->dp2->spData.dwSPHeaderSize);

   rmsg->envelope.dwMagic    = DPMSGMAGIC_DPLAYMSG;
   rmsg->envelope.wCommandId = DPMSGCMD_ENUMSESSIONSREPLY;
   rmsg->envelope.wVersion   = DPMSGVER_DP6;

   CopyMemory( &rmsg->sd, lpDP->dp2->lpSessionDesc,
               lpDP->dp2->lpSessionDesc->dwSize );
   rmsg->dwUnknown = 0x0000005c;
   if( bAnsi )
   {
       MultiByteToWideChar( CP_ACP, 0, lpDP->dp2->lpSessionDesc->u1.lpszSessionNameA, -1,
                            (LPWSTR)(rmsg+1), dwVariableLen );
   }
   else
   {
       strcpyW( (LPWSTR)(rmsg+1), lpDP->dp2->lpSessionDesc->u1.lpszSessionName );
   }
 }
	/* DPLAYX.DLL name server implementation
	*
	* Copyright 2000-2001 - Peter Hunnisett
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
	*/

	/* NOTE: Methods with the NS_ prefix are name server methods */

	#include <stdarg.h>
	#include <string.h>

	#define NONAMELESSUNION
	#define NONAMELESSSTRUCT
	#include "windef.h"
	#include "winbase.h"
	#include "winnls.h"
	#include "wine/unicode.h"
	#include "wine/debug.h"
	#include "mmsystem.h"

	#include "dplayx_global.h"
	#include "name_server.h"
	#include "wine/dplaysp.h"
	#include "dplayx_messages.h"
	#include "dplayx_queue.h"

	/* FIXME: Need to create a crit section, store and use it */

	WINE_DEFAULT_DEBUG_CHANNEL(dplay);

	/* NS specific structures */
	struct NSCacheData
	{
	DPQ_ENTRY(NSCacheData) next;

	DWORD dwTime; /* Time at which data was last known valid */
	LPDPSESSIONDESC2 data;

	LPVOID lpNSAddrHdr;

	};
	typedef struct NSCacheData NSCacheData, *lpNSCacheData;

	struct NSCache
	{
	lpNSCacheData present; /* keep track of what is to be looked at when walking */

	DPQ_HEAD(NSCacheData) first;

	BOOL bNsIsLocal;
	LPVOID lpLocalAddrHdr; /* FIXME: Not yet used */
	LPVOID lpRemoteAddrHdr; /* FIXME: Not yet used */
	};
	typedef struct NSCache NSCache, *lpNSCache;

	/* Function prototypes */
	static DPQ_DECL_DELETECB( cbDeleteNSNodeFromHeap, lpNSCacheData );

	/* Name Server functions
	* ---------------------
	*/
	void NS_SetLocalComputerAsNameServer( LPCDPSESSIONDESC2 lpsd, LPVOID lpNSInfo )
	{
	lpNSCache lpCache = (lpNSCache)lpNSInfo;

	lpCache->bNsIsLocal = TRUE;
	}

	static DPQ_DECL_COMPARECB( cbUglyPig, GUID )
	{
	return IsEqualGUID( elem1, elem2 );
	}

	/* Store the given NS remote address for future reference */
	void NS_AddRemoteComputerAsNameServer( LPCVOID lpcNSAddrHdr,
	DWORD dwHdrSize,
	LPCDPMSG_ENUMSESSIONSREPLY lpcMsg,
	LPVOID lpNSInfo )
	{
	DWORD len;
	lpNSCache lpCache = (lpNSCache)lpNSInfo;
	lpNSCacheData lpCacheNode;

	TRACE( "%p, %p, %p\n", lpcNSAddrHdr, lpcMsg, lpNSInfo );

	/* See if we can find this session. If we can, remove it as it's a dup */
	DPQ_REMOVE_ENTRY_CB( lpCache->first, next, data->guidInstance, cbUglyPig,
	lpcMsg->sd.guidInstance, lpCacheNode );

	if( lpCacheNode != NULL )
	{
	TRACE( "Duplicate session entry for %s removed - updated version kept\n",
	debugstr_guid( &lpCacheNode->data->guidInstance ) );
	cbDeleteNSNodeFromHeap( lpCacheNode );
	}

	/* Add this to the list */
	lpCacheNode = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof( *lpCacheNode ) );

	if( lpCacheNode == NULL )
	{
	ERR( "no memory for NS node\n" );
	return;
	}

	lpCacheNode->lpNSAddrHdr = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY,
	dwHdrSize );
	CopyMemory( lpCacheNode->lpNSAddrHdr, lpcNSAddrHdr, dwHdrSize );

	lpCacheNode->data = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof( *(lpCacheNode->data) ) );

	if( lpCacheNode->data == NULL )
	{
	ERR( "no memory for SESSIONDESC2\n" );
	HeapFree( GetProcessHeap(), 0, lpCacheNode );
	return;
	}

	*lpCacheNode->data = lpcMsg->sd;
	len = WideCharToMultiByte( CP_ACP, 0, (LPCWSTR)(lpcMsg+1), -1, NULL, 0, NULL, NULL );
	if ((lpCacheNode->data->u1.lpszSessionNameA = HeapAlloc( GetProcessHeap(), 0, len )))
	{
	WideCharToMultiByte( CP_ACP, 0, (LPCWSTR)(lpcMsg+1), -1,
	lpCacheNode->data->u1.lpszSessionNameA, len, NULL, NULL );
	}

	lpCacheNode->dwTime = timeGetTime();

	DPQ_INSERT(lpCache->first, lpCacheNode, next );

	lpCache->present = lpCacheNode;

	/* Use this message as an opportunity to weed out any old sessions so
	* that we don't enum them again
	*/
	NS_PruneSessionCache( lpNSInfo );
	}

	LPVOID NS_GetNSAddr( LPVOID lpNSInfo )
	{
	lpNSCache lpCache = (lpNSCache)lpNSInfo;

	FIXME( ":quick stub\n" );

	/* Ok. Cheat and don't search for the correct stuff just take the first.
	* FIXME: In the future how are we to know what is _THE_ enum we used?
	* This is going to have to go into dplay somehow. Perhaps it
	* comes back with app server id for the join command! Oh... that
	* must be it. That would make this method obsolete once that's
	* in place.
	*/
	#if 1
	return lpCache->first.lpQHFirst->lpNSAddrHdr;
	#else
	/* FIXME: Should convert over to this */
	return lpCache->bNsIsLocal ? lpCache->lpLocalAddrHdr
	: lpCache->lpRemoteAddrHdr;
	#endif
	}

	/* Get the magic number associated with the Name Server */
	DWORD NS_GetNsMagic( LPVOID lpNSInfo )
	{
	LPDWORD lpHdrInfo = NS_GetNSAddr( lpNSInfo );

	return lpHdrInfo[1];
	}

	void NS_SetLocalAddr( LPVOID lpNSInfo, LPCVOID lpHdr, DWORD dwHdrSize )
	{
	lpNSCache lpCache = (lpNSCache)lpNSInfo;

	lpCache->lpLocalAddrHdr = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, dwHdrSize );

	CopyMemory( lpCache->lpLocalAddrHdr, lpHdr, dwHdrSize );
	}

	/* This function is responsible for sending a request for all other known
	nameservers to send us what sessions they have registered locally
	*/
	HRESULT NS_SendSessionRequestBroadcast( LPCGUID lpcGuid,
	DWORD dwFlags,
	const SPINITDATA *lpSpData )

	{
	DPSP_ENUMSESSIONSDATA data;
	LPDPMSG_ENUMSESSIONSREQUEST lpMsg;

	TRACE( "enumerating for guid %s\n", debugstr_guid( lpcGuid ) );

	/* Get the SP to deal with sending the EnumSessions request */
	FIXME( ": not all data fields are correct\n" );

	data.dwMessageSize = lpSpData->dwSPHeaderSize + sizeof( lpMsg ); /FIXME!*/
	data.lpMessage = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY,
	data.dwMessageSize );
	data.lpISP = lpSpData->lpISP;
	data.bReturnStatus = (dwFlags & DPENUMSESSIONS_RETURNSTATUS) ? TRUE : FALSE;


	lpMsg = (LPDPMSG_ENUMSESSIONSREQUEST)(((BYTE*)data.lpMessage)+lpSpData->dwSPHeaderSize);

	/* Setup EnumSession request message */
	lpMsg->envelope.dwMagic = DPMSGMAGIC_DPLAYMSG;
	lpMsg->envelope.wCommandId = DPMSGCMD_ENUMSESSIONSREQUEST;
	lpMsg->envelope.wVersion = DPMSGVER_DP6;

	lpMsg->dwPasswordSize = 0; /* FIXME: If enumerating passwords..? */
	lpMsg->dwFlags = dwFlags;

	lpMsg->guidApplication = *lpcGuid;

	return (lpSpData->lpCB->EnumSessions)( &data );
	}

	/* Delete a name server node which has been allocated on the heap */
	static DPQ_DECL_DELETECB( cbDeleteNSNodeFromHeap, lpNSCacheData )
	{
	/* NOTE: This proc doesn't deal with the walking pointer */

	/* FIXME: Memory leak on data (contained ptrs) */
	HeapFree( GetProcessHeap(), 0, elem->data );
	HeapFree( GetProcessHeap(), 0, elem->lpNSAddrHdr );
	HeapFree( GetProcessHeap(), 0, elem );
	}

	/* Render all data in a session cache invalid */
	void NS_InvalidateSessionCache( LPVOID lpNSInfo )
	{
	lpNSCache lpCache = (lpNSCache)lpNSInfo;

	if( lpCache == NULL )
	{
	ERR( ": invalidate nonexistent cache\n" );
	return;
	}

	DPQ_DELETEQ( lpCache->first, next, lpNSCacheData, cbDeleteNSNodeFromHeap );

	/* NULL out the walking pointer */
	lpCache->present = NULL;

	lpCache->bNsIsLocal = FALSE;

	}

	/* Create and initialize a session cache */
	BOOL NS_InitializeSessionCache( LPVOID* lplpNSInfo )
	{
	lpNSCache lpCache = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof( *lpCache ) );

	*lplpNSInfo = lpCache;

	if( lpCache == NULL )
	{
	return FALSE;
	}

	DPQ_INIT(lpCache->first);
	lpCache->present = NULL;

	lpCache->bNsIsLocal = FALSE;

	return TRUE;
	}

	/* Delete a session cache */
	void NS_DeleteSessionCache( LPVOID lpNSInfo )
	{
	NS_InvalidateSessionCache( (lpNSCache)lpNSInfo );
	}

	/* Reinitialize the present pointer for this cache */
	void NS_ResetSessionEnumeration( LPVOID lpNSInfo )
	{
	((lpNSCache)lpNSInfo)->present = ((lpNSCache)lpNSInfo)->first.lpQHFirst;
	}

	LPDPSESSIONDESC2 NS_WalkSessions( LPVOID lpNSInfo )
	{
	LPDPSESSIONDESC2 lpSessionDesc;
	lpNSCache lpCache = (lpNSCache)lpNSInfo;

	/* FIXME: The pointers could disappear when walking if a prune happens */

	/* Test for end of the list */
	if( lpCache->present == NULL )
	{
	return NULL;
	}

	lpSessionDesc = lpCache->present->data;

	/* Advance tracking pointer */
	lpCache->present = lpCache->present->next.lpQNext;

	return lpSessionDesc;
	}

	/* This method should check to see if there are any sessions which are
	* older than the criteria. If so, just delete that information.
	*/
	/* FIXME: This needs to be called by some periodic timer */
	void NS_PruneSessionCache( LPVOID lpNSInfo )
	{
	lpNSCache lpCache = lpNSInfo;

	const DWORD dwPresentTime = timeGetTime();
	const DWORD dwPrunePeriod = DPMSG_WAIT_60_SECS; /* is 60 secs enough? */

	/* This silly little algorithm is based on the fact we keep entries in
	* the queue in a time based order. It also assumes that it is not possible
	* to wrap around over yourself (which is not unreasonable).
	* The if statements verify if the first entry in the queue is less
	* than dwPrunePeriod old depending on the "clock" roll over.
	*/
	for( ;; )
	{
	lpNSCacheData lpFirstData;

	if( DPQ_IS_EMPTY(lpCache->first) )
	{
	/* Nothing to prune */
	break;
	}

	/* Deal with time in a wrap around safe manner - unsigned arithmetic.
	* Check the difference in time */
	if( (dwPresentTime - (DPQ_FIRST(lpCache->first)->dwTime)) < dwPrunePeriod )
	{
	/* First entry has not expired yet; don't prune */
	break;
	}

	lpFirstData = DPQ_FIRST(lpCache->first);
	DPQ_REMOVE( lpCache->first, DPQ_FIRST(lpCache->first), next );
	cbDeleteNSNodeFromHeap( lpFirstData );
	}

	}

	/* NAME SERVER Message stuff */
	void NS_ReplyToEnumSessionsRequest( LPCVOID lpcMsg,
	LPVOID* lplpReplyData,
	LPDWORD lpdwReplySize,
	IDirectPlay2Impl* lpDP )
	{
	LPDPMSG_ENUMSESSIONSREPLY rmsg;
	DWORD dwVariableSize;
	DWORD dwVariableLen;
	/* LPCDPMSG_ENUMSESSIONSREQUEST msg = (LPDPMSG_ENUMSESSIONSREQUEST)lpcMsg; */
	BOOL bAnsi = TRUE; /* FIXME: This needs to be in the DPLAY interface */

	FIXME( ": few fixed + need to check request for response\n" );

	if (bAnsi)
	{
	dwVariableLen = MultiByteToWideChar( CP_ACP, 0,
	lpDP->dp2->lpSessionDesc->u1.lpszSessionNameA,
	-1, NULL, 0 );
	}
	else
	{
	dwVariableLen = strlenW( lpDP->dp2->lpSessionDesc->u1.lpszSessionName ) + 1;
	}

	dwVariableSize = dwVariableLen * sizeof( WCHAR );

	*lpdwReplySize = lpDP->dp2->spData.dwSPHeaderSize +
	sizeof( *rmsg ) + dwVariableSize;
	*lplpReplyData = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY,
	*lpdwReplySize );

	rmsg = (LPDPMSG_ENUMSESSIONSREPLY)( (BYTE)lplpReplyData +
	lpDP->dp2->spData.dwSPHeaderSize);

	rmsg->envelope.dwMagic = DPMSGMAGIC_DPLAYMSG;
	rmsg->envelope.wCommandId = DPMSGCMD_ENUMSESSIONSREPLY;
	rmsg->envelope.wVersion = DPMSGVER_DP6;

	CopyMemory( &rmsg->sd, lpDP->dp2->lpSessionDesc,
	lpDP->dp2->lpSessionDesc->dwSize );
	rmsg->dwUnknown = 0x0000005c;
	if( bAnsi )
	{
	MultiByteToWideChar( CP_ACP, 0, lpDP->dp2->lpSessionDesc->u1.lpszSessionNameA, -1,
	(LPWSTR)(rmsg+1), dwVariableLen );
	}
	else
	{
	strcpyW( (LPWSTR)(rmsg+1), lpDP->dp2->lpSessionDesc->u1.lpszSessionName );
	}
	}