/*
 * tclWinSock.c --
 *
 *	This file contains Windows-specific socket related code.
 *
 * Copyright (c) 1995-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclWinSock.c,v 1.70.2.7 2010/09/17 16:21:53 rmax Exp $
 * RCS: @(#) $Id: tclWinSock.c,v 1.70.2.8 2010/09/27 11:00:45 rmax Exp $
 *
 * -----------------------------------------------------------------------
 *
 * General information on how this module works.
 *
 * - Each Tcl-thread with its sockets maintains an internal window to receive
 *   socket messages from the OS.
 *
 * - To ensure that message reception is always running this window is
 *   actually owned and handled by an internal thread. This we call the
 *   co-thread of Tcl's thread.
 *
 * - The whole structure is set up by InitSockets() which is called for each
 *   Tcl thread. The implementation of the co-thread is in SocketThread(),
 *   and the messages are handled by SocketProc(). The connection between
 *   both is not directly visible, it is done through a Win32 window class.
 *   This class is initialized by InitSockets() as well, and used in the
 *   creation of the message receiver windows.
 *
 * - An important thing to note is that *both* thread and co-thread have
 *   access to the list of sockets maintained in the private TSD data of the
 *   thread. The co-thread was given access to it upon creation through the
 *   new thread's client-data.
 *
 *   Because of this dual access the TSD data contains an OS mutex, the
 *   "socketListLock", to mediate exclusion between thread and co-thread.
 *
 *   The co-thread's access is all in SocketProc(). The thread's access is
 *   through SocketEventProc() (1) and the functions called by it.
 *
 *   (Ad 1) This is the handler function for all queued socket events, which
 *          all the OS messages are translated to through the EventSource (2)
 *          driven by the OS messages.
 *
 *   (Ad 2) The main functions for this are SocketSetupProc() and
 *          SocketCheckProc().
 */

#include "tclWinInt.h"

#ifdef _MSC_VER
#   pragma comment (lib, "ws2_32")
#endif

#define SOCKET_MESSAGE	    WM_USER+1
#define SOCKET_SELECT	    WM_USER+2
#define SOCKET_TERMINATE    WM_USER+3
#define SELECT		    TRUE
#define UNSELECT	    FALSE

/*
 * This is needed to comply with the strict aliasing rules of GCC, but it also
 * simplifies casting between the different sockaddr types.
 */
typedef union {
    struct sockaddr sa;
    struct sockaddr_in sa4;
    struct sockaddr_in6 sa6;
    struct sockaddr_storage sas;
} address;

#ifndef IN6_ARE_ADDR_EQUAL
#define IN6_ARE_ADDR_EQUAL IN6_ADDR_EQUAL
#endif

typedef struct SocketInfo SocketInfo;

typedef struct TcpFdList {
    SocketInfo *infoPtr;
    int fd;
    struct TcpFdList *next;
} TcpFdList;

/*
 * The following structure is used to store the data associated with each
 * socket.
 */

struct SocketInfo {
typedef struct SocketInfo {
    Tcl_Channel channel;	/* Channel associated with this socket. */
    struct TcpFdList *sockets;	/* Windows SOCKET handle. */
    SOCKET socket;		/* Windows SOCKET handle. */
    int flags;			/* Bit field comprised of the flags described
				 * below. */
    int watchEvents;		/* OR'ed combination of FD_READ, FD_WRITE,
				 * FD_CLOSE, FD_ACCEPT and FD_CONNECT that
				 * indicate which events are interesting. */
    int readyEvents;		/* OR'ed combination of FD_READ, FD_WRITE,
				 * FD_CLOSE, FD_ACCEPT and FD_CONNECT that
				 * indicate which events have occurred. */
    int selectEvents;		/* OR'ed combination of FD_READ, FD_WRITE,
				 * FD_CLOSE, FD_ACCEPT and FD_CONNECT that
				 * indicate which events are currently being
				 * selected. */
    int acceptEventCount;	/* Count of the current number of FD_ACCEPTs
				 * that have arrived and not yet processed. */
    Tcl_TcpAcceptProc *acceptProc;
				/* Proc to call on accept. */
    ClientData acceptProcData;	/* The data for the accept proc. */
    int lastError;		/* Error code from last message. */
    struct SocketInfo *nextPtr;	/* The next socket on the per-thread socket
				 * list. */
};
} SocketInfo;

/*
 * The following structure is what is added to the Tcl event queue when a
 * socket event occurs.
 */

typedef struct SocketEvent {

/*
 * Static functions defined in this file.
 */

static SocketInfo *	CreateSocket(Tcl_Interp *interp, int port,
			    const char *host, int server, const char *myaddr,
			    int myport, int async);
#if 0
static int		CreateSocketAddress(LPSOCKADDR_IN sockaddrPtr,
			    const char *host, int port);
#endif
static void		InitSockets(void);
static SocketInfo *	NewSocketInfo(SOCKET socket);
static void		SocketExitHandler(ClientData clientData);
static LRESULT CALLBACK	SocketProc(HWND hwnd, UINT message, WPARAM wParam,
			    LPARAM lParam);
static int		SocketsEnabled(void);
static void		TcpAccept(TcpFdList *fds);
static void		TcpAccept(SocketInfo *infoPtr);
static int		WaitForSocketEvent(SocketInfo *infoPtr, int events,
			    int *errorCodePtr);
static DWORD WINAPI	SocketThread(LPVOID arg);
static void		TcpThreadActionProc(ClientData instanceData,
			    int action);

static Tcl_EventCheckProc	SocketCheckProc;

    for (infoPtr = tsdPtr->socketList; infoPtr != NULL;
	    infoPtr = infoPtr->nextPtr) {
	if ((infoPtr->readyEvents & infoPtr->watchEvents)
		&& !(infoPtr->flags & SOCKET_PENDING)) {
	    infoPtr->flags |= SOCKET_PENDING;
	    evPtr = (SocketEvent *) ckalloc(sizeof(SocketEvent));
	    evPtr->header.proc = SocketEventProc;
	    evPtr->socket = infoPtr->sockets->fd;
	    evPtr->socket = infoPtr->socket;
	    Tcl_QueueEvent((Tcl_Event *) evPtr, TCL_QUEUE_TAIL);
	}
    }
    SetEvent(tsdPtr->socketListLock);
}

/*

				 * such as TCL_FILE_EVENTS. */
{
    SocketInfo *infoPtr;
    SocketEvent *eventPtr = (SocketEvent *) evPtr;
    int mask = 0;
    int events;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    TcpFdList *fds;

    if (!(flags & TCL_FILE_EVENTS)) {
	return 0;
    }

    /*
     * Find the specified socket on the socket list.
     */

    WaitForSingleObject(tsdPtr->socketListLock, INFINITE);
    for (infoPtr = tsdPtr->socketList; infoPtr != NULL;
	    infoPtr = infoPtr->nextPtr) {
	if (infoPtr->sockets->fd == eventPtr->socket) {
	if (infoPtr->socket == eventPtr->socket) {
	    break;
	}
    }
    SetEvent(tsdPtr->socketListLock);

    /*
     * Discard events that have gone stale.
     */

    if (!infoPtr) {
	return 1;
    }

    infoPtr->flags &= ~SOCKET_PENDING;

    /*
     * Handle connection requests directly.
     */

    if (infoPtr->readyEvents & FD_ACCEPT) {
	for (fds = infoPtr->sockets; fds != NULL; fds = fds->next) {
	    TcpAccept(fds);
	TcpAccept(infoPtr);
	}
	return 1;
    }

    /*
     * Mask off unwanted events and compute the read/write mask so we can
     * notify the channel.
     */

	 * select handler and keep waiting.
	 */

	SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
		(WPARAM) UNSELECT, (LPARAM) infoPtr);

	FD_ZERO(&readFds);
	FD_SET(infoPtr->sockets->fd, &readFds);
	FD_SET(infoPtr->socket, &readFds);
	timeout.tv_usec = 0;
	timeout.tv_sec = 0;

	if (select(0, &readFds, NULL, NULL, &timeout) != 0) {
	    mask |= TCL_READABLE;
	} else {
	    infoPtr->readyEvents &= ~(FD_READ);

    if (SocketsEnabled()) {
	/*
	 * Clean up the OS socket handle. The default Windows setting for a
	 * socket is SO_DONTLINGER, which does a graceful shutdown in the
	 * background.
	 */

	if (closesocket(infoPtr->sockets->fd) == SOCKET_ERROR) {
	if (closesocket(infoPtr->socket) == SOCKET_ERROR) {
	    TclWinConvertWSAError((DWORD) WSAGetLastError());
	    errorCode = Tcl_GetErrno();
	}
    }

    /*
     * TIP #218. Removed the code removing the structure from the global

	    break;
	default:
	    if (interp) {
		Tcl_AppendResult(interp, "Socket close2proc called bidirectionally", NULL);
	    }
	    return TCL_ERROR;
	}
    if (shutdown(infoPtr->sockets->fd,sd) == SOCKET_ERROR) {
    if (shutdown(infoPtr->socket,sd) == SOCKET_ERROR) {
	TclWinConvertWSAError((DWORD) WSAGetLastError());
	errorCode = Tcl_GetErrno();
    }

    return errorCode;
}


 */

static SocketInfo *
NewSocketInfo(
    SOCKET socket)
{
    SocketInfo *infoPtr;
    TcpFdList *fds;
    infoPtr = (SocketInfo *) ckalloc((unsigned) sizeof(SocketInfo));
    /* ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); */
    fds = (TcpFdList*) ckalloc(sizeof(TcpFdList));

    fds->fd = socket;
    fds->next = NULL;
    fds->infoPtr = infoPtr;
    infoPtr = (SocketInfo *) ckalloc((unsigned) sizeof(SocketInfo));
    /* ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); */
    infoPtr->channel = 0;
    infoPtr->sockets = fds;
    infoPtr->socket = socket;
    infoPtr->flags = 0;
    infoPtr->watchEvents = 0;
    infoPtr->readyEvents = 0;
    infoPtr->selectEvents = 0;
    infoPtr->acceptEventCount = 0;
    infoPtr->acceptProc = NULL;
    infoPtr->acceptProcData = NULL;

    int myport,			/* Optional client-side port */
    int async)			/* If nonzero, connect client socket
				 * asynchronously. */
{
    u_long flag = 1;		/* Indicates nonblocking mode. */
    int asyncConnect = 0;	/* Will be 1 if async connect is in
				 * progress. */
    int chosenport = 0;
    struct addrinfo *addrlist = NULL, *addrPtr;	/* socket address */
    struct addrinfo *myaddrlist = NULL, *myaddrPtr; /* Socket address for client */
    SOCKADDR_IN sockaddr;	/* Socket address */
    SOCKADDR_IN mysockaddr;	/* Socket address for client */
    const char *errorMsg = NULL;
    SOCKET sock = INVALID_SOCKET;
    SocketInfo *infoPtr = NULL;	/* The returned value. */
    SocketInfo *infoPtr;	/* The returned value. */
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    TclThreadDataKeyGet(&dataKey);

    /*
     * Check that WinSock is initialized; do not call it if not, to prevent
     * system crashes. This can happen at exit time if the exit handler for
     * WinSock ran before other exit handlers that want to use sockets.
     */

    if (!SocketsEnabled()) {
	return NULL;
    }

    if (!TclCreateSocketAddress(interp, &addrlist, host, port, server, &errorMsg)) {
    if (!CreateSocketAddress(&sockaddr, host, port)) {
	goto error;
    }
    if ((myaddr != NULL || myport != 0) &&
    if (!TclCreateSocketAddress(interp, &myaddrlist, myaddr, myport, 1, &errorMsg)) {
	    !CreateSocketAddress(&mysockaddr, myaddr, myport)) {
	goto error;
    }

    if (server) {
	TcpFdList *fds = NULL, *newfds;
	for (addrPtr = addrlist; addrPtr != NULL; addrPtr = addrPtr->ai_next) {
	    sock = socket(addrPtr->ai_family, SOCK_STREAM, 0);
	    if (sock == INVALID_SOCKET) {
		TclWinConvertWSAError((DWORD) WSAGetLastError());
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock == INVALID_SOCKET) {
	goto error;
		continue;
	    }
	
	    /*
	     * Win-NT has a misfeature that sockets are inherited in child
	     * processes by default. Turn off the inherit bit.
	     */
	    
	    SetHandleInformation((HANDLE) sock, HANDLE_FLAG_INHERIT, 0);
	    
	    /*
	     * Set kernel space buffering
	     */
	    
	    TclSockMinimumBuffers((int) sock, TCP_BUFFER_SIZE);
    }

    /*
     * Win-NT has a misfeature that sockets are inherited in child processes
     * by default. Turn off the inherit bit.
     */

    SetHandleInformation((HANDLE) sock, HANDLE_FLAG_INHERIT, 0);

    /*
     * Set kernel space buffering
     */

    TclSockMinimumBuffers((int) sock, TCP_BUFFER_SIZE);

	    /*
	     * Make sure we use the same port when opening two server sockets
	     * for IPv4 and IPv6.
	     *
	     * As sockaddr_in6 uses the same offset and size for the port
	     * member as sockaddr_in, we can handle both through the IPv4 API.
	     */
	    if (port == 0 && chosenport != 0) {
		((struct sockaddr_in *) addrPtr->ai_addr)->sin_port =
		    htons(chosenport);
	    }

	    /*
	     * Bind to the specified port. Note that we must not call
	     * setsockopt with SO_REUSEADDR because Microsoft allows addresses
	     * to be reused even if they are still in use.
	     *
	     * Bind should not be affected by the socket having already been
	     * set into nonblocking mode. If there is trouble, this is one
	     * place to look for bugs.
	     */
    if (server) {
	/*
	 * Bind to the specified port. Note that we must not call setsockopt
	 * with SO_REUSEADDR because Microsoft allows addresses to be reused
	 * even if they are still in use.
	 *
	 * Bind should not be affected by the socket having already been set
	 * into nonblocking mode. If there is trouble, this is one place to
	 * look for bugs.
	 */

	    if (bind(sock, addrPtr->ai_addr, addrPtr->ai_addrlen)
	if (bind(sock, (SOCKADDR *) &sockaddr, sizeof(SOCKADDR_IN))
		== SOCKET_ERROR) {
		TclWinConvertWSAError((DWORD) WSAGetLastError());
	    goto error;
		closesocket(sock);
		continue;
	    }
	    if (port == 0 && chosenport == 0) {
		address sockname;
		socklen_t namelen = sizeof(sockname);
		/*
		 * Synchronize port numbers when binding to port 0 of multiple
		 * addresses.
		 */
		if (getsockname(sock, &sockname.sa, &namelen) >= 0) {
		    chosenport = ntohs(sockname.sa4.sin_port);
		}
	    }
	    
	    /*
	     * Set the maximum number of pending connect requests to the max value
	     * allowed on each platform (Win32 and Win32s may be different, and
	     * there may be differences between TCP/IP stacks).
	     */
	    
	    if (listen(sock, SOMAXCONN) == SOCKET_ERROR) {
		TclWinConvertWSAError((DWORD) WSAGetLastError());
	}

	/*
	 * Set the maximum number of pending connect requests to the max value
	 * allowed on each platform (Win32 and Win32s may be different, and
	 * there may be differences between TCP/IP stacks).
	 */

	if (listen(sock, SOMAXCONN) == SOCKET_ERROR) {
	    goto error;
		closesocket(sock);
		continue;
	    }
	    
	}

	    if (infoPtr == NULL) {
		/*
		 * Add this socket to the global list of sockets.
		 */
		
		infoPtr = NewSocketInfo(sock);
	/*
	 * Add this socket to the global list of sockets.
	 */

	infoPtr = NewSocketInfo(sock);
		fds = infoPtr->sockets;
		
		/*
		 * Set up the select mask for connection request events.
		 */
		
		infoPtr->selectEvents = FD_ACCEPT;
		infoPtr->watchEvents |= FD_ACCEPT;
		
	    } else {

	/*
	 * Set up the select mask for connection request events.
	 */

	infoPtr->selectEvents = FD_ACCEPT;
	infoPtr->watchEvents |= FD_ACCEPT;

    } else {
		newfds = (TcpFdList *) ckalloc((unsigned) sizeof(TcpFdList));
		memset(newfds, (int) 0, sizeof(TcpFdList));
		newfds->fd = sock;
		newfds->infoPtr = infoPtr;
		newfds->next = NULL;
		fds->next = newfds;
		fds = newfds;
	    }
	}
    } else {
	for (myaddrPtr = myaddrlist; myaddrPtr != NULL;
	     myaddrPtr = myaddrPtr->ai_next) {
	    for (addrPtr = addrlist; addrPtr != NULL;
		 addrPtr = addrPtr->ai_next) {
		/*
		 * No need to try combinations of local and remote addresses
	/*
	 * Try to bind to a local port, if specified.
		 * of different families.
		 */
	 */
		if (myaddrPtr->ai_family != addrPtr->ai_family) {
		    continue;
		}


	if (myaddr != NULL || myport != 0) {
		sock = socket(myaddrPtr->ai_family, SOCK_STREAM, 0);
		if (sock == INVALID_SOCKET) {
		    TclWinConvertWSAError((DWORD) WSAGetLastError());
		    continue;
		}
		
	    if (bind(sock, (SOCKADDR *) &mysockaddr, sizeof(SOCKADDR_IN))
		/*
		 * Win-NT has a misfeature that sockets are inherited in child
		 * processes by default. Turn off the inherit bit.
		 */

		    == SOCKET_ERROR) {
		SetHandleInformation((HANDLE) sock, HANDLE_FLAG_INHERIT, 0);

		goto error;
		/*
		 * Set kernel space buffering
		 */
		
	    }
		TclSockMinimumBuffers((int) sock, TCP_BUFFER_SIZE);
		
	}
		/*
		 * Try to bind to a local port.
		 */
		

		if (bind(sock, myaddrPtr->ai_addr, myaddrPtr->ai_addrlen)
		    == SOCKET_ERROR) {
		    TclWinConvertWSAError((DWORD) WSAGetLastError());
		    goto looperror;
		}
		/*
		 * Set the socket into nonblocking mode if the connect should
		 * be done in the background.
		 */
		if (async) {
		    if (ioctlsocket(sock, (long) FIONBIO, &flag)
	/*
	 * Set the socket into nonblocking mode if the connect should be done
	 * in the background.
	 */

	if (async) {
	    if (ioctlsocket(sock, (long) FIONBIO, &flag) == SOCKET_ERROR) {
			== SOCKET_ERROR) {
			TclWinConvertWSAError((DWORD) WSAGetLastError());
			goto looperror;
		    }
		}
		goto error;
	    }
	}

		/*
		 * Attempt to connect to the remote socket.
		 */
		
		if (connect(sock, addrPtr->ai_addr, addrPtr->ai_addrlen)
		    == SOCKET_ERROR) {
		    TclWinConvertWSAError((DWORD) WSAGetLastError());
		    if (Tcl_GetErrno() != EWOULDBLOCK) {
			goto looperror;
		    }
		    
		    /*
		     * The connection is progressing in the background.
		     */
	/*
	 * Attempt to connect to the remote socket.
	 */

	if (connect(sock, (SOCKADDR *) &sockaddr,
		sizeof(SOCKADDR_IN)) == SOCKET_ERROR) {
	    TclWinConvertWSAError((DWORD) WSAGetLastError());
	    if (Tcl_GetErrno() != EWOULDBLOCK) {
		goto error;
	    }

	    /*
	     * The connection is progressing in the background.
	     */

		    asyncConnect = 1;
	    asyncConnect = 1;
		    goto connected;
		} else {
		    goto connected;
		}
	}
	    looperror:
		if (sock != INVALID_SOCKET) {
		    closesocket(sock);
		    sock = INVALID_SOCKET;
		}

	    }
	}
	goto error;

    connected:
	/*
	 * Add this socket to the global list of sockets.
	 */
	

	infoPtr = NewSocketInfo(sock);
	

	/*
	 * Set up the select mask for read/write events. If the
	 * connect attempt has not completed, include connect events.
	 * Set up the select mask for read/write events. If the connect
	 * attempt has not completed, include connect events.
	 */
	    

	infoPtr->selectEvents = FD_READ | FD_WRITE | FD_CLOSE;
	if (asyncConnect) {
	    infoPtr->flags |= SOCKET_ASYNC_CONNECT;
	    infoPtr->selectEvents |= FD_CONNECT;
	}
    }

  error:
    if (addrlist == NULL)
	freeaddrinfo(addrlist);
    if (myaddrlist == NULL)
	freeaddrinfo(myaddrlist);

    /*
     * Register for interest in events in the select mask. Note that this
     * automatically places the socket into non-blocking mode.
     */
    

    if (infoPtr != NULL) {
	ioctlsocket(sock, (long) FIONBIO, &flag);
	SendMessage(tsdPtr->hwnd, SOCKET_SELECT, (WPARAM) SELECT, (LPARAM) infoPtr);
	
	return infoPtr;
    }

    ioctlsocket(sock, (long) FIONBIO, &flag);
    SendMessage(tsdPtr->hwnd, SOCKET_SELECT, (WPARAM) SELECT, (LPARAM) infoPtr);

    return infoPtr;

  error:
    TclWinConvertWSAError((DWORD) WSAGetLastError());
    if (interp != NULL) {
	Tcl_AppendResult(interp, "couldn't open socket: ",
		Tcl_PosixError(interp), NULL);
    }
    if (sock != INVALID_SOCKET) {
	closesocket(sock);
    }
    return NULL;
}

#if 0
/*
 *----------------------------------------------------------------------
 *
 * CreateSocketAddress --
 *
 *	This function initializes a sockaddr structure for a host and port.
 *

     * incorrect behavior on 64 bit machines such as DEC Alphas. Should we
     * modify this code to do an explicit memcpy?
     */

    sockaddrPtr->sin_addr.s_addr = addr.s_addr;
    return 1;			/* Success. */
}
#endif

/*
 *----------------------------------------------------------------------
 *
 * WaitForSocketEvent --
 *
 *	Waits until one of the specified events occurs on a socket.

     */

    infoPtr = CreateSocket(interp, port, host, 0, myaddr, myport, async);
    if (infoPtr == NULL) {
	return NULL;
    }

    wsprintfA(channelName, "sock%d", infoPtr->sockets->fd);
    wsprintfA(channelName, "sock%d", infoPtr->socket);

    infoPtr->channel = Tcl_CreateChannel(&tcpChannelType, channelName,
	    infoPtr, (TCL_READABLE | TCL_WRITABLE));
    if (Tcl_SetChannelOption(interp, infoPtr->channel, "-translation",
	    "auto crlf") == TCL_ERROR) {
	Tcl_Close((Tcl_Interp *) NULL, infoPtr->channel);
	return (Tcl_Channel) NULL;

     * Start watching for read/write events on the socket.
     */

    infoPtr->selectEvents = FD_READ | FD_CLOSE | FD_WRITE;
    SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
	    (WPARAM) SELECT, (LPARAM) infoPtr);

    wsprintfA(channelName, "sock%d", infoPtr->sockets->fd);
    wsprintfA(channelName, "sock%d", infoPtr->socket);
    infoPtr->channel = Tcl_CreateChannel(&tcpChannelType, channelName,
	    infoPtr, (TCL_READABLE | TCL_WRITABLE));
    Tcl_SetChannelOption(NULL, infoPtr->channel, "-translation", "auto crlf");
    return infoPtr->channel;
}

/*

    if (infoPtr == NULL) {
	return NULL;
    }

    infoPtr->acceptProc = acceptProc;
    infoPtr->acceptProcData = acceptProcData;

    wsprintfA(channelName, "sock%d", infoPtr->sockets->fd);
    wsprintfA(channelName, "sock%d", infoPtr->socket);

    infoPtr->channel = Tcl_CreateChannel(&tcpChannelType, channelName,
	    infoPtr, 0);
    if (Tcl_SetChannelOption(interp, infoPtr->channel, "-eofchar", "")
	    == TCL_ERROR) {
	Tcl_Close((Tcl_Interp *) NULL, infoPtr->channel);
	return (Tcl_Channel) NULL;

 *	Invokes the accept proc which may invoke arbitrary Tcl code.
 *
 *----------------------------------------------------------------------
 */

static void
TcpAccept(
    TcpFdList *fds)	/* Socket to accept. */
    SocketInfo *infoPtr)	/* Socket to accept. */
{
    SOCKET newSocket;
    SocketInfo *newInfoPtr;
    SocketInfo *infoPtr = fds->infoPtr;
    SOCKADDR_IN addr;
    int len;
    char channelName[16 + TCL_INTEGER_SPACE];
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    TclThreadDataKeyGet(&dataKey);

    /*
     * Accept the incoming connection request.
     */

    len = sizeof(SOCKADDR_IN);

    newSocket = accept(fds->fd, (SOCKADDR *)&addr, &len);
    newSocket = accept(infoPtr->socket, (SOCKADDR *)&addr,
	    &len);

    /*
     * Protect access to sockets (acceptEventCount, readyEvents) in socketList
     * by the lock.  Fix for SF Tcl Bug 3056775.
     */
    WaitForSingleObject(tsdPtr->socketListLock, INFINITE);

    /*
     * Clear the ready mask so we can detect the next connection request. Note
     * that connection requests are level triggered, so if there is a request
     * already pending, a new event will be generated.
     */

    if (newSocket == INVALID_SOCKET) {
	infoPtr->acceptEventCount = 0;
	infoPtr->readyEvents &= ~(FD_ACCEPT);

	SetEvent(tsdPtr->socketListLock);
	return;
    }

    /*
     * It is possible that more than one FD_ACCEPT has been sent, so an extra
     * count must be kept. Decrement the count, and reset the readyEvent bit
     * if the count is no longer > 0.
     */

    infoPtr->acceptEventCount--;

    if (infoPtr->acceptEventCount <= 0) {
	infoPtr->readyEvents &= ~(FD_ACCEPT);
    }

    SetEvent(tsdPtr->socketListLock);

    /*
     * Win-NT has a misfeature that sockets are inherited in child processes
     * by default. Turn off the inherit bit.
     */

    SetHandleInformation((HANDLE) newSocket, HANDLE_FLAG_INHERIT, 0);

     * Select on read/write events and create the channel.
     */

    newInfoPtr->selectEvents = (FD_READ | FD_WRITE | FD_CLOSE);
    SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
	    (WPARAM) SELECT, (LPARAM) newInfoPtr);

    wsprintfA(channelName, "sock%d", newInfoPtr->sockets->fd);
    wsprintfA(channelName, "sock%d", newInfoPtr->socket);
    newInfoPtr->channel = Tcl_CreateChannel(&tcpChannelType, channelName,
	    newInfoPtr, (TCL_READABLE | TCL_WRITABLE));
    if (Tcl_SetChannelOption(NULL, newInfoPtr->channel, "-translation",
	    "auto crlf") == TCL_ERROR) {
	Tcl_Close((Tcl_Interp *) NULL, newInfoPtr->channel);
	return;
    }

     * read. We have to simulate blocking behavior here since we are always
     * using non-blocking sockets.
     */

    while (1) {
	SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
		(WPARAM) UNSELECT, (LPARAM) infoPtr);
	bytesRead = recv(infoPtr->sockets->fd, buf, toRead, 0);
	bytesRead = recv(infoPtr->socket, buf, toRead, 0);
	infoPtr->readyEvents &= ~(FD_READ);

	/*
	 * Check for end-of-file condition or successful read.
	 */

	if (bytesRead == 0) {

	return -1;
    }

    while (1) {
	SendMessage(tsdPtr->hwnd, SOCKET_SELECT,
		(WPARAM) UNSELECT, (LPARAM) infoPtr);

	bytesWritten = send(infoPtr->sockets->fd, buf, toWrite, 0);
	bytesWritten = send(infoPtr->socket, buf, toWrite, 0);
	if (bytesWritten != SOCKET_ERROR) {
	    /*
	     * Since Windows won't generate a new write event until we hit an
	     * overflow condition, we need to force the event loop to poll
	     * until the condition changes.
	     */

	if (interp) {
	    Tcl_AppendResult(interp, "winsock is not initialized", NULL);
	}
	return TCL_ERROR;
    }

    infoPtr = (SocketInfo *) instanceData;
    sock = infoPtr->sockets->fd;
    sock = infoPtr->socket;

#ifdef TCL_FEATURE_KEEPALIVE_NAGLE
    if (!strcasecmp(optionName, "-keepalive")) {
	BOOL val = FALSE;
	int boolVar, rtn;

	if (Tcl_GetBoolean(interp, value, &boolVar) != TCL_OK) {

    const char *optionName,	/* Name of the option to retrieve the value
				 * for, or NULL to get all options and their
				 * values. */
    Tcl_DString *dsPtr)		/* Where to store the computed value;
				 * initialized by caller. */
{
    SocketInfo *infoPtr;
    SOCKADDR_IN sockname;
    SOCKADDR_IN peername;
    char host[NI_MAXHOST], port[NI_MAXSERV];
    struct hostent *hostEntPtr;
    SOCKET sock;
    int size = sizeof(SOCKADDR_IN);
    size_t len = 0;
    char buf[TCL_INTEGER_SPACE];

    /*
     * Check that WinSock is initialized; do not call it if not, to prevent
     * system crashes. This can happen at exit time if the exit handler for
     * WinSock ran before other exit handlers that want to use sockets.
     */

    if (!SocketsEnabled()) {
	if (interp) {
	    Tcl_AppendResult(interp, "winsock is not initialized", NULL);
	}
	return TCL_ERROR;
    }

    infoPtr = (SocketInfo *) instanceData;
    sock = (int) infoPtr->sockets->fd;
    sock = (int) infoPtr->socket;
    if (optionName != NULL) {
	len = strlen(optionName);
    }

    if ((len > 1) && (optionName[1] == 'e') &&
	    (strncmp(optionName, "-error", len) == 0)) {
	int optlen;

	    Tcl_DStringAppend(dsPtr, Tcl_ErrnoMsg(Tcl_GetErrno()), -1);
	}
	return TCL_OK;
    }

    if ((len == 0) || ((len > 1) && (optionName[1] == 'p') &&
	    (strncmp(optionName, "-peername", len) == 0))) {
	address peername;
	socklen_t size = sizeof(peername);
	if (getpeername(sock, (LPSOCKADDR) &(peername.sa), &size) == 0) {
	if (getpeername(sock, (LPSOCKADDR) &peername, &size) == 0) {
	    if (len == 0) {
		Tcl_DStringAppendElement(dsPtr, "-peername");
		Tcl_DStringStartSublist(dsPtr);
	    }
	    Tcl_DStringAppendElement(dsPtr, inet_ntoa(peername.sin_addr));

	    getnameinfo(&(peername.sa), size, host, sizeof(host),
                        NULL, 0, NI_NUMERICHOST);
	    Tcl_DStringAppendElement(dsPtr, host);
	    if (peername.sin_addr.s_addr == 0) {
		hostEntPtr = NULL;
	    } else {
		hostEntPtr = gethostbyaddr((char *) &(peername.sin_addr),
			sizeof(peername.sin_addr), AF_INET);
	    }
	    if (hostEntPtr != NULL) {
		Tcl_DStringAppendElement(dsPtr, hostEntPtr->h_name);
	    getnameinfo(&(peername.sa), size, host, sizeof(host),
                        port, sizeof(port), NI_NUMERICSERV);
	    Tcl_DStringAppendElement(dsPtr, host);
	    Tcl_DStringAppendElement(dsPtr, port);
	    } else {
		Tcl_DStringAppendElement(dsPtr, inet_ntoa(peername.sin_addr));
	    }
	    TclFormatInt(buf, ntohs(peername.sin_port));
	    Tcl_DStringAppendElement(dsPtr, buf);
	    if (len == 0) {
		Tcl_DStringEndSublist(dsPtr);
	    } else {
		return TCL_OK;
	    }
	} else {
	    /*

		return TCL_ERROR;
	    }
	}
    }

    if ((len == 0) || ((len > 1) && (optionName[1] == 's') &&
	    (strncmp(optionName, "-sockname", len) == 0))) {

	if (getsockname(sock, (LPSOCKADDR) &sockname, &size) == 0) {
	TcpFdList *fds;
        address sockname;
        socklen_t size;
	int found = 0;
	
	if (len == 0) {
	    Tcl_DStringAppendElement(dsPtr, "-sockname");
	    Tcl_DStringStartSublist(dsPtr);
	}
	    if (len == 0) {
		Tcl_DStringAppendElement(dsPtr, "-sockname");
		Tcl_DStringStartSublist(dsPtr);
	    }
	for (fds = infoPtr->sockets; fds != NULL; fds = fds->next) {
	    sock = fds->fd;
	    size = sizeof(sockname);
	    if (getsockname(sock, &(sockname.sa), &size) >= 0) {
		int flags;
		found = 1;
		
		getnameinfo(&sockname.sa, size, host, sizeof(host),
			    NULL, 0, NI_NUMERICHOST);
		Tcl_DStringAppendElement(dsPtr, host);
	    Tcl_DStringAppendElement(dsPtr, inet_ntoa(sockname.sin_addr));
	    
		/*
		 * We don't want to resolve INADDR_ANY and sin6addr_any; they
		 * can sometimes cause problems (and never have a name).
		 */
		flags = NI_NUMERICSERV;
		if (sockname.sa.sa_family == AF_INET) {
		    if (sockname.sa4.sin_addr.s_addr == INADDR_ANY) {
			flags |= NI_NUMERICHOST;
	    if (sockname.sin_addr.s_addr == 0) {
		hostEntPtr = NULL;
		    }
		} else if (sockname.sa.sa_family == AF_INET6) {
	    } else {
		    if ((IN6_ARE_ADDR_EQUAL(&sockname.sa6.sin6_addr,
					    &in6addr_any))
			|| (IN6_IS_ADDR_V4MAPPED(&sockname.sa6.sin6_addr) &&
			    sockname.sa6.sin6_addr.s6_addr[12] == 0 &&
			    sockname.sa6.sin6_addr.s6_addr[13] == 0 &&
		hostEntPtr = gethostbyaddr((char *) &(sockname.sin_addr),
			sizeof(peername.sin_addr), AF_INET);
			    sockname.sa6.sin6_addr.s6_addr[14] == 0 &&
			    sockname.sa6.sin6_addr.s6_addr[15] == 0)) {
			flags |= NI_NUMERICHOST;
		    }
	    }
		}
		getnameinfo(&sockname.sa, size, host, sizeof(host),
	    if (hostEntPtr != NULL) {
			    port, sizeof(port), flags);
		Tcl_DStringAppendElement(dsPtr, host);
		Tcl_DStringAppendElement(dsPtr, port);
		Tcl_DStringAppendElement(dsPtr, hostEntPtr->h_name);
	    } else {
		Tcl_DStringAppendElement(dsPtr, inet_ntoa(sockname.sin_addr));
	    }
	}
	if (found) {
	    TclFormatInt(buf, ntohs(sockname.sin_port));
	    Tcl_DStringAppendElement(dsPtr, buf);
	    if (len == 0) {
		Tcl_DStringEndSublist(dsPtr);
	    } else {
		return TCL_OK;
	    }
	} else {
	    if (interp) {
		TclWinConvertWSAError((DWORD) WSAGetLastError());
		Tcl_AppendResult(interp, "can't get sockname: ",
				 Tcl_PosixError(interp), NULL);
			Tcl_PosixError(interp), NULL);
	    }
	    return TCL_ERROR;
	}
    }
	

#ifdef TCL_FEATURE_KEEPALIVE_NAGLE
    if (len == 0 || !strncmp(optionName, "-keepalive", len)) {
	int optlen;
	BOOL opt = FALSE;

	if (len == 0) {
	    Tcl_DStringAppendElement(dsPtr, "-keepalive");

TcpGetHandleProc(
    ClientData instanceData,	/* The socket state. */
    int direction,		/* Not used. */
    ClientData *handlePtr)	/* Where to store the handle. */
{
    SocketInfo *statePtr = (SocketInfo *) instanceData;

    *handlePtr = INT2PTR(statePtr->sockets->fd);
    *handlePtr = INT2PTR(statePtr->socket);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * SocketThread --

	 * Find the specified socket on the socket list and update its
	 * eventState flag.
	 */

	WaitForSingleObject(tsdPtr->socketListLock, INFINITE);
	for (infoPtr = tsdPtr->socketList; infoPtr != NULL;
		infoPtr = infoPtr->nextPtr) {
	    if (infoPtr->sockets->fd == socket) {
	    if (infoPtr->socket == socket) {
		/*
		 * Update the socket state.
		 *
		 * A count of FD_ACCEPTS is stored, so if an FD_CLOSE event
		 * happens, then clear the FD_ACCEPT count. Otherwise,
		 * increment the count if the current event is an FD_ACCEPT.
		 */

	}
	SetEvent(tsdPtr->socketListLock);
	break;

    case SOCKET_SELECT:
	infoPtr = (SocketInfo *) lParam;
	if (wParam == SELECT) {
	    WSAAsyncSelect(infoPtr->sockets->fd, hwnd,
	    WSAAsyncSelect(infoPtr->socket, hwnd,
		    SOCKET_MESSAGE, infoPtr->selectEvents);
	} else {
	    /*
	     * Clear the selection mask
	     */

	    WSAAsyncSelect(infoPtr->sockets->fd, hwnd, 0, 0);
	    WSAAsyncSelect(infoPtr->socket, hwnd, 0, 0);
	}
	break;

    case SOCKET_TERMINATE:
	DestroyWindow(hwnd);
	break;
    }