*    0 if successful or POSIX error code if failed.
 *
 * Side effects:
 *    Sets the device into blocking or nonblocking mode.
 *
 *-----------------------------------------------------------------------------
 */
static int TlsBlockModeProc(ClientData instanceData, int mode) {
    State *statePtr = (State *) instanceData;

    if (mode == TCL_MODE_NONBLOCKING) {
	statePtr->flags |= TLS_TCL_ASYNC;
    } else {
	statePtr->flags &= ~(TLS_TCL_ASYNC);
    }

 *    0 if successful or POSIX error code if failed.
 *
 * Side effects:
 *    Closes the socket of the channel.
 *
 *-----------------------------------------------------------------------------
 */
static int TlsCloseProc(ClientData instanceData, Tcl_Interp *interp) {
    State *statePtr = (State *) instanceData;

    dprintf("TlsCloseProc(%p)", (void *) statePtr);

    /* Flush any pending data */

    /* Send shutdown notification. Will return 0 while in process, then 1 when complete. */
    /* Closes the write direction of the connection; the read direction is closed by the peer. */
    /* Does not affect socket state. Don't call after fatal error. */
    if (statePtr->ssl != NULL && !(statePtr->flags & TLS_TCL_HANDSHAKE_FAILED)) {
	SSL_shutdown(statePtr->ssl);
    }

    /* Tls_Free calls Tls_Clean */
    Tcl_EventuallyFree((ClientData)statePtr, Tls_Free);
    return 0;
}

/*
 *-----------------------------------------------------------------------------
 *
 * TlsClose2Proc --
 *
 *	Similar to TlsCloseProc, but allows for separate close read and write
 *	side of channel.
 *
 *-----------------------------------------------------------------------------
 */
static int TlsClose2Proc(ClientData instanceData,    /* The socket state. */
    Tcl_Interp *interp,		/* For errors - can be NULL. */
    int flags)			/* Flags to close read and/or write side of channel */
{
    State *statePtr = (State *) instanceData;

    dprintf("TlsClose2Proc(%p)", (void *) statePtr);

 *
 * Data is received in whole blocks known as records from the peer. A whole
 * record is processed (e.g. decrypted) in one go and is buffered by OpenSSL
 * until it is read by the application via a call to SSL_read.
 *
 *-----------------------------------------------------------------------------
 */
static int TlsInputProc(ClientData instanceData, char *buf, int bufSize, int *errorCodePtr) {
    unsigned long backingError;
    State *statePtr = (State *) instanceData;
    int bytesRead, err;
    *errorCodePtr = 0;

    dprintf("Read(%d)", bufSize);

 *    to a POSIX error code if an error occurred, or 0 if none.
 *
 * Side effects:
 *    Writes output on the output device of the channel.
 *
 *-----------------------------------------------------------------------------
 */
static int TlsOutputProc(ClientData instanceData, const char *buf, int toWrite, int *errorCodePtr) {
    unsigned long backingError;
    State *statePtr = (State *) instanceData;
    int written, err;
    *errorCodePtr = 0;

    dprintf("Write(%p, %d)", (void *) statePtr, toWrite);
    dprintBuffer(buf, toWrite);

 *
 * Side effects:
 *    Updates channel option to new value.
 *
 *-----------------------------------------------------------------------------
 */
static int
TlsSetOptionProc(ClientData instanceData,    /* Socket state. */
    Tcl_Interp *interp,		/* For errors - can be NULL. */
    const char *optionName,	/* Name of the option to set the value for, or
				 * NULL to get all options and their values. */
    const char *optionValue)	/* Value for option. */
{
    State *statePtr = (State *) instanceData;
    Tcl_Channel parent = Tls_GetParent(statePtr, TLS_TCL_FASTPATH);

 *
 * Side effects:
 *    None.
 *
 *-------------------------------------------------------------------
 */
static int
TlsGetOptionProc(ClientData instanceData,    /* Socket state. */
    Tcl_Interp *interp,		/* For errors - can be NULL. */
    const char *optionName,	/* Name of the option to retrieve the value for, or
				 * NULL to get all options and their values. */
    Tcl_DString *optionValue)	/* Where to store the computed value initialized by caller. */
{
    State *statePtr = (State *) instanceData;
    Tcl_Channel parent = Tls_GetParent(statePtr, TLS_TCL_FASTPATH);

 *        None.
 *
 * Side effects:
 *	Creates notification event.
 *
 *-----------------------------------------------------------------------------
 */
static void TlsChannelHandlerTimer(ClientData clientData) {
    State *statePtr = (State *) clientData;
    int mask = statePtr->want; /* Init to SSL_ERROR_WANT_READ and SSL_ERROR_WANT_WRITE */

    dprintf("Called");

    statePtr->timer = (Tcl_TimerToken) NULL;

 * Side effects:
 *	Sets up the time-based notifier so that future events on the channel
 *	will be seen by TCL.
 *
 *-----------------------------------------------------------------------------
 */
static void
TlsWatchProc(ClientData instanceData,    /* The socket state. */
    int mask)			/* Events of interest; an OR-ed combination of
				 * TCL_READABLE, TCL_WRITABLE and TCL_EXCEPTION. */
{
    Tcl_Channel     parent;
    State *statePtr = (State *) instanceData;
    Tcl_DriverWatchProc *watchProc;
    int pending = 0;

	    statePtr->timer = (Tcl_TimerToken) NULL;
	}

    } else {
	/* Add timer, if none */
	if (statePtr->timer == (Tcl_TimerToken) NULL) {
	    dprintf("Creating a new timer since data appears to be waiting");
	    statePtr->timer = Tcl_CreateTimerHandler(TLS_TCL_DELAY, TlsChannelHandlerTimer, (ClientData) statePtr);
	}
    }
}

/*
 *-----------------------------------------------------------------------------
 *
 * TlsGetHandleProc --
 *
 *	This procedure is invoked by the generic IO level to retrieve an OS
 *	specific handle associated with the channel. Not used for transforms.
 *
 * Results:
 *    The appropriate Tcl_File handle or NULL if none.
 *
 * Side effects:
 *    None.
 *
 *-----------------------------------------------------------------------------
 */
static int TlsGetHandleProc(ClientData instanceData,    /* Socket state. */
    int direction,		/* TCL_READABLE or TCL_WRITABLE */
    ClientData *handlePtr)	/* Handle associated with the channel */
{
    State *statePtr = (State *) instanceData;

    return Tcl_GetChannelHandle(Tls_GetParent(statePtr, TLS_TCL_FASTPATH), direction, handlePtr);
}

/*

 *    Type of event or 0 if failed
 *
 * Side effects:
 *    May process the incoming event by itself.
 *
 *-----------------------------------------------------------------------------
 */
static int TlsNotifyProc(ClientData instanceData,    /* Socket state. */
    int mask)			/* type of event that occurred:
				 * OR-ed combination of TCL_READABLE or TCL_WRITABLE */
{
    State *statePtr = (State *) instanceData;
    int errorCode = 0;

    dprintf("Called");