*
 * Side effects:
 *    Sets the device into blocking or nonblocking mode.
 *
 *-------------------------------------------------------------------
 */
static int TlsBlockModeProc(void *instanceData, int mode) {
    State *statePtr = (State *)instanceData;

    if (mode == TCL_MODE_NONBLOCKING) {
	statePtr->flags |= TLS_TCL_ASYNC;
    } else {
	statePtr->flags &= ~(TLS_TCL_ASYNC);
    }
    return(0);

		*errorCodePtr = backingError;
		if (*errorCodePtr == ECONNRESET) {
		    *errorCodePtr = ECONNABORTED;
		}
		}

		statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;

		return -1;
	case SSL_ERROR_SSL:
	    dprintf("Got permanent fatal SSL error, aborting immediately");
		Tls_Error(statePtr, (char *)ERR_reason_error_string(ERR_get_error()));
	    statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
	    *errorCodePtr = ECONNABORTED;
	    return(-1);



	default:
	    dprintf("We got a confusing reply: %i", rc);
	    *errorCodePtr = Tcl_GetErrno();
	    dprintf("ERR(%d, %d) ", rc, *errorCodePtr);
	    return -1;
    }

#if 0
    if (statePtr->flags & TLS_TCL_SERVER) {
	dprintf("This is an TLS server, checking the certificate for the peer");

	err = SSL_get_verify_result(statePtr->ssl);

static int TlsInputProc(
    void *instanceData,
    char *buf,
    int bufSize,
    int *errorCodePtr)
{
    unsigned long backingError;
    State *statePtr = (State *)instanceData;
    int bytesRead;
    int tlsConnect;
    int err;

    *errorCodePtr = 0;

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

static int TlsOutputProc(
    void *instanceData,
    const char *buf,
    int toWrite,
    int *errorCodePtr)
{
    unsigned long backingError;
    State *statePtr = (State *)instanceData;
    int written, err;
    int tlsConnect;

    *errorCodePtr = 0;

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

    dprintf("Output(%d) -> %d", toWrite, written);
    return(written);
}

/*
 *-------------------------------------------------------------------
 *
 * TlsSetOptionProc --
 *
 *    Sets an option value for a SSL socket based channel, or a
 *    list of all options and their values.
 *
 * Results:
 *    TCL_OK if successful or TCL_ERROR if failed.
 *
 * Side effects:
 *    Updates channel option to new value.
 *
 *-------------------------------------------------------------------
 */
static int
TlsSetOptionProc(void *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 downChan = Tls_GetParent(statePtr, TLS_TCL_FASTPATH);
    Tcl_DriverSetOptionProc *setOptionProc;

    setOptionProc = Tcl_ChannelSetOptionProc(Tcl_GetChannelType(downChan));
    if (setOptionProc != NULL) {
	return (*setOptionProc)(Tcl_GetChannelInstanceData(downChan), interp, optionName, optionValue);
    } else if (optionName == (char*) NULL) {
	/*
	 * Request is query for all options, this is ok.
	 */
	return TCL_OK;
    }
    /*
     * Request for a specific option has to fail, we don't have any.
     */
    return Tcl_BadChannelOption(interp, optionName, "");
}

/*
 *-------------------------------------------------------------------
 *
 * TlsGetOptionProc --
 *
 *    Gets an option value for a SSL socket based channel, or a
 *    list of all options and their values.
 *
 * Results:
 *    A standard Tcl result. The value of the specified option or a

TlsGetOptionProc(
    void *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 downChan = Tls_GetParent(statePtr, TLS_TCL_FASTPATH);
    Tcl_DriverGetOptionProc *getOptionProc;

    getOptionProc = Tcl_ChannelGetOptionProc(Tcl_GetChannelType(downChan));
    if (getOptionProc != NULL) {
	return (*getOptionProc)(Tcl_GetChannelInstanceData(downChan), interp, optionName, optionValue);
    } else if (optionName == (char*) NULL) {
	/*
	 * Request is query for all options, this is ok.
	 */
	return TCL_OK;
    }
    /*
     * Request for a specific option has to fail, we don't have any.
     */
    return Tcl_BadChannelOption(interp, optionName, "");
}

/*
 *-------------------------------------------------------------------
 *
 * TlsWatchProc --
 *

static void
TlsWatchProc(
    void *instanceData,    /* The socket state. */
    int mask)			/* Events of interest; an OR-ed combination of
				 * TCL_READABLE, TCL_WRITABLE and TCL_EXCEPTION. */
{
    Tcl_Channel     downChan;
    State *statePtr = (State *)instanceData;

    dprintf("TlsWatchProc(0x%x)", mask);

    /* Pretend to be dead as long as the verify callback is running.
     * Otherwise that callback could be invoked recursively. */
    if (statePtr->flags & TLS_TCL_CALLBACK) {
	dprintf("Callback is on-going, doing nothing");
	return;
    }

    dprintFlags(statePtr);

    downChan = Tls_GetParent(statePtr, TLS_TCL_FASTPATH);

    if (statePtr->flags & TLS_TCL_HANDSHAKE_FAILED) {
	dprintf("Asked to watch a socket with a failed handshake -- nothing can happen here");
	dprintf("Unregistering interest in the lower channel");

	Tcl_GetChannelType(downChan)->watchProc(Tcl_GetChannelInstanceData(downChan), 0);
	statePtr->watchMask = 0;
	return;
    }

    statePtr->watchMask = mask;

    /* No channel handlers any more. We will be notified automatically
     * about events on the channel below via a call to our
     * 'TransformNotifyProc'. But we have to pass the interest down now.
     * We are allowed to add additional 'interest' to the mask if we want
     * to. But this transformation has no such interest. It just passes
     * the request down, unchanged.
     */
    dprintf("Registering our interest in the lower channel (chan=%p)", (void *) downChan);

    Tcl_GetChannelType(downChan)->watchProc(Tcl_GetChannelInstanceData(downChan), mask);

    /*
     * Management of the internal timer.
     */
    if (statePtr->timer != (Tcl_TimerToken) NULL) {
	dprintf("A timer was found, deleting it");
	Tcl_DeleteTimerHandler(statePtr->timer);

static const Tcl_ChannelType tlsChannelType = {
    "tls",			/* Type name */
    TCL_CHANNEL_VERSION_5,	/* v5 channel */
    TlsCloseProc,		/* Close proc */
    TlsInputProc,		/* Input proc */
    TlsOutputProc,		/* Output proc */
    0,			/* Seek proc */
    TlsSetOptionProc,		/* Set option proc */
    TlsGetOptionProc,		/* Get option proc */
    TlsWatchProc,		/* Initialize notifier */
    TlsGetHandleProc,		/* Get OS handles out of channel */
    TlsClose2Proc,		/* close2proc */
    TlsBlockModeProc,		/* Set blocking/nonblocking mode*/
    0,			/* Flush proc */
    TlsNotifyProc,		/* Handling of events bubbling up */