static int  TlsCloseProc _ANSI_ARGS_((ClientData instanceData, Tcl_Interp *interp));
static int  TlsInputProc _ANSI_ARGS_((ClientData instanceData, char *buf, int bufSize, int *errorCodePtr));
static int  TlsOutputProc _ANSI_ARGS_((ClientData instanceData, CONST char *buf, int toWrite, int *errorCodePtr));
static int  TlsGetOptionProc _ANSI_ARGS_((ClientData instanceData, Tcl_Interp *interp, CONST84 char *optionName, Tcl_DString *dsPtr));
static void TlsWatchProc _ANSI_ARGS_((ClientData instanceData, int mask));
static int  TlsGetHandleProc _ANSI_ARGS_((ClientData instanceData, int direction, ClientData *handlePtr));
static int  TlsNotifyProc _ANSI_ARGS_((ClientData instanceData, int mask));
#if 0
static void TlsChannelHandler _ANSI_ARGS_((ClientData clientData, int mask));
#endif
static void TlsChannelHandlerTimer _ANSI_ARGS_((ClientData clientData));

/*
 * TLS Channel Type
 */
static Tcl_ChannelType *tlsChannelType = NULL;

















/*
 *-------------------------------------------------------------------
 *
 * Tls_ChannelType --
 *
 *	Return the correct TLS channel driver info
 *
 * Results:
 *	The correct channel driver for the current version of Tcl.
 *
 * Side effects:
 *	None.
 *
 *-------------------------------------------------------------------
 */
Tcl_ChannelType *Tls_ChannelType(void) {
	unsigned int size;

	/*
	 * Initialize the channel type if necessary
	 */
	if (tlsChannelType == NULL) {
		/*
		 * Allocation of a new channeltype structure is not easy, because of
		 * the various verson of the core and subsequent changes to the
		 * structure. The main challenge is to allocate enough memory for
		 * modern versions even if this extsension is compiled against one
		 * of the older variant!
		 *
		 * (1) Versions before stubs (8.0.x) are simple, because they are
		 *     supported only if the extension is compiled against exactly
		 *     that version of the core.
		 *
		 * (2) With stubs we just determine the difference between the older
		 *     and modern variant and overallocate accordingly if compiled
		 *     against an older variant.
		 */
		size = sizeof(Tcl_ChannelType); /* Base size */

		tlsChannelType = (Tcl_ChannelType *) ckalloc(size);
		memset((VOID *) tlsChannelType, 0, size);

		/*
		 * Common elements of the structure (no changes in location or name)
		 * close2Proc, seekProc, setOptionProc stay NULL.
		 */

		tlsChannelType->typeName	= "tls";
		tlsChannelType->closeProc	= TlsCloseProc;
		tlsChannelType->inputProc	= TlsInputProc;
		tlsChannelType->outputProc	= TlsOutputProc;
		tlsChannelType->getOptionProc	= TlsGetOptionProc;
		tlsChannelType->watchProc	= TlsWatchProc;
		tlsChannelType->getHandleProc	= TlsGetHandleProc;

		/*
		 * Compiled against 8.3.2+. Direct access to all elements possible. Use
		 * channelTypeVersion information to select the values to use.
		 */

		/*
		 * For the 8.3.2 core we present ourselves as a version 2
		 * driver. This means a special value in version (ex
		 * blockModeProc), blockModeProc in a different place and of
		 * course usage of the handlerProc.
		 */
		tlsChannelType->version       = TCL_CHANNEL_VERSION_2;
		tlsChannelType->blockModeProc = TlsBlockModeProc;
		tlsChannelType->handlerProc   = TlsNotifyProc;
	}

	return(tlsChannelType);
}

/*
 *-------------------------------------------------------------------
 *
 * TlsBlockModeProc --
 *

                                         * 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);

 *
 * TlsGetHandleProc --
 *
 *	Called from Tcl_GetChannelFile to retrieve o/s file handler
 *	from the SSL socket based channel.
 *
 * Results:
 *	The appropriate Tcl_File or NULL if not present. 
 *
 * Side effects:
 *	None.
 *
 *-------------------------------------------------------------------
 */
static int TlsGetHandleProc(ClientData instanceData, int direction, ClientData *handlePtr) {

     * Notify the upper channel of the current BIO state so the event
     * continues to propagate up the chain.
     *
     * stanton: It looks like this could result in an infinite loop if
     * the upper channel doesn't cause ChannelHandler to be removed
     * before Tcl_NotifyChannel calls channel handlers on the lower channel.
     */
    
    Tcl_NotifyChannel(statePtr->self, mask);
    
    if (statePtr->timer != (Tcl_TimerToken)NULL) {
	Tcl_DeleteTimerHandler(statePtr->timer);
	statePtr->timer = (Tcl_TimerToken)NULL;
    }
    if ((mask & TCL_READABLE) && Tcl_InputBuffered(statePtr->self) > 0) {
	/*
	 * Data is waiting, flush it out in short time