*	0 if successful, the value of Tcl_GetErrno() 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);

	Tls_Clean(statePtr);
	Tcl_EventuallyFree((ClientData)statePtr, Tls_Free);

	dprintf("Returning TCL_OK");

	return(TCL_OK);

	/* Interp is unused. */
	interp = interp;
}

/*
 *-------------------------------------------------------------------
 *
 * TlsInputProc --
 *

 *
 * Side effects:
 *	Reads input from the input device of the channel.
 *
 *-------------------------------------------------------------------
 */


static int TlsInputProc(ClientData instanceData, char *buf, int bufSize, int *errorCodePtr) {





	State *statePtr = (State *) instanceData;
	int bytesRead;
	int tlsConnect;
	int err;

	*errorCodePtr = 0;

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

	if (statePtr->flags & TLS_TCL_CALLBACK) {
		/* don't process any bytes while verify callback is running */
		dprintf("Callback is running, reading 0 bytes");
		return(0);


	}


	dprintf("Calling Tls_WaitForConnect");
	tlsConnect = Tls_WaitForConnect(statePtr, errorCodePtr);
	if (tlsConnect < 0) {
		dprintf("Got an error (bytesRead = %i)", bytesRead);

		if (*errorCodePtr == ECONNRESET) {
			dprintf("Got connection reset");
			/* Soft EOF */
			*errorCodePtr = 0;
			bytesRead = 0;
		}


		return(0);
	}

	if (statePtr->flags & TLS_TCL_INIT) {
		statePtr->flags &= ~(TLS_TCL_INIT);
	}

	/*
	 * We need to clear the SSL error stack now because we sometimes reach
	 * this function with leftover errors in the stack.  If BIO_read
	 * returns -1 and intends EAGAIN, there is a leftover error, it will be
	 * misconstrued as an error, not EAGAIN.
	 *
	 * Alternatively, we may want to handle the <0 return codes from
	 * BIO_read specially (as advised in the RSA docs).  TLS's lower level BIO
	 * functions play with the retry flags though, and this seems to work
	 * correctly.  Similar fix in TlsOutputProc. - hobbs
	 */
	ERR_clear_error();
	bytesRead = BIO_read(statePtr->bio, buf, bufSize);
	dprintf("BIO_read -> %d", bytesRead);


	err = SSL_get_error(statePtr->ssl, bytesRead);




	if (BIO_should_retry(statePtr->bio)) {
		dprintf("I/O failed, will retry based on EAGAIN");
		*errorCodePtr = EAGAIN;
	}

	switch (err) {
		case SSL_ERROR_NONE:
			dprintBuffer(buf, bytesRead);
			break;
		case SSL_ERROR_SSL:
			Tls_Error(statePtr, TCLTLS_SSL_ERROR(statePtr->ssl, bytesRead));
			*errorCodePtr = ECONNABORTED;
			break;
		case SSL_ERROR_SYSCALL:
			dprintf("I/O error reading, treating it as EOF");

			*errorCodePtr = 0;
			bytesRead = 0;
			break;
	}



	dprintf("Input(%d) -> %d [%d]", bufSize, bytesRead, *errorCodePtr);
	return(bytesRead);
}

/*
 *-------------------------------------------------------------------
 *
 * TlsOutputProc --
 *
 *	This procedure is invoked by the generic IO level
 *       to write output to a SSL socket based channel.
 *
 * Results:
 *	The number of bytes written is returned. An output argument is
 *	set to a POSIX error code if an error occurred, or zero.
 *
 * Side effects:
 *	Writes output on the output device of the channel.
 *
 *-------------------------------------------------------------------
 */


static int TlsOutputProc(ClientData instanceData, CONST char *buf, int toWrite, int *errorCodePtr) {




	State *statePtr = (State *) instanceData;
	int written, err;

	*errorCodePtr = 0;

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

	if (statePtr->flags & TLS_TCL_CALLBACK) {
		dprintf("Don't process output while callbacks are running")
		written = -1;
		*errorCodePtr = EAGAIN;

		return(-1);
	}


	dprintf("Calling Tls_WaitForConnect");
	written = Tls_WaitForConnect(statePtr, errorCodePtr);
	if (written < 0) {
		dprintf("Tls_WaitForConnect returned %i (err = %i)", written, *errorCodePtr);

		return(-1);
	}




	if (toWrite == 0) {
		dprintf("zero-write");
		err = BIO_flush(statePtr->bio);

		if (err <= 0) {
			dprintf("Flushing failed");

			*errorCodePtr = EIO;
			written = 0;
			return(-1);
		}

		written = 0;
		*errorCodePtr = 0;
		return(0);
	}

	/*
	 * We need to clear the SSL error stack now because we sometimes reach
	 * this function with leftover errors in the stack.  If BIO_write
	 * returns -1 and intends EAGAIN, there is a leftover error, it will be
	 * misconstrued as an error, not EAGAIN.
	 *
	 * Alternatively, we may want to handle the <0 return codes from
	 * BIO_write specially (as advised in the RSA docs).  TLS's lower level
	 * BIO functions play with the retry flags though, and this seems to
	 * work correctly.  Similar fix in TlsInputProc. - hobbs
	 */
	ERR_clear_error();
	written = BIO_write(statePtr->bio, buf, toWrite);
	dprintf("BIO_write(%p, %d) -> [%d]", (void *) statePtr, toWrite, written);



	err = SSL_get_error(statePtr->ssl, written);
	switch (err) {
		case SSL_ERROR_NONE:
			if (written < 0) {
				written = 0;
			}
			break;
		case SSL_ERROR_WANT_WRITE:
			dprintf(" write W BLOCK");
			break;
		case SSL_ERROR_WANT_READ:
			dprintf(" write R BLOCK");
			break;
		case SSL_ERROR_WANT_X509_LOOKUP:
			dprintf(" write X BLOCK");
			break;
		case SSL_ERROR_ZERO_RETURN:
			dprintf(" closed");
			written = 0;
			break;
		case SSL_ERROR_SYSCALL:
			*errorCodePtr = Tcl_GetErrno();
			dprintf(" [%d] syscall errr: %d", written, *errorCodePtr);

			written = -1;
			break;
		case SSL_ERROR_SSL:
			Tls_Error(statePtr, TCLTLS_SSL_ERROR(statePtr->ssl, written));
			*errorCodePtr = ECONNABORTED;
			written = -1;
			break;
		default:
			dprintf(" unknown err: %d", err);
			break;
	}


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

/*
 *-------------------------------------------------------------------
 *
 * TlsGetOptionProc --
 *

					 * NULL to get all options and
					 * their values. */
	Tcl_DString *dsPtr)		/* 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, dsPtr);
    } else if (optionName == (char*) NULL) {
        /*

    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);
	    statePtr->timer = (Tcl_TimerToken) NULL;
	}

	if ((mask & TCL_READABLE) && Tcl_InputBuffered(statePtr->self) > 0) {
	    /*
	     * There is interest in readable events and we actually have
	     * data waiting, so generate a timer to flush that.
	     */
            dprintf("Creating a new timer since data appears to be waiting");
	    statePtr->timer = Tcl_CreateTimerHandler(TLS_TCL_DELAY,
		    TlsChannelHandlerTimer, (ClientData) statePtr);
	}
}

/*
 *-------------------------------------------------------------------

 *	The appropriate Tcl_File or NULL if not present. 
 *
 * Side effects:
 *	None.
 *
 *-------------------------------------------------------------------
 */

static int TlsGetHandleProc(ClientData instanceData, int direction, ClientData *handlePtr) {



	State *statePtr = (State *) instanceData;

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

/*
 *-------------------------------------------------------------------
 *
 * TlsNotifyProc --
 *
 *	Handler called by Tcl to inform us of activity
 *	on the underlying channel.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May process the incoming event by itself.
 *
 *-------------------------------------------------------------------
 */

static int TlsNotifyProc(ClientData instanceData, int mask) {




	State *statePtr = (State *) instanceData;
	int errorCode;

	/*
	 * An event occured in the underlying channel.  This
	 * transformation doesn't process such events thus returns the
	 * incoming mask unchanged.
	 */

	if (statePtr->timer != (Tcl_TimerToken) NULL) {
		/*
		 * Delete an existing timer. It was not fired, yet we are
		 * here, so the channel below generated such an event and we
		 * don't have to. The renewal of the interest after the
		 * execution of channel handlers will eventually cause us to
		 * recreate the timer (in WatchProc).
		 */

		Tcl_DeleteTimerHandler(statePtr->timer);
		statePtr->timer = (Tcl_TimerToken) NULL;
	}

	if (statePtr->flags & TLS_TCL_CALLBACK) {
		dprintf("Returning 0 due to callback");
		return 0;
	}




	dprintf("Calling Tls_WaitForConnect");
	errorCode = 0;
	if (Tls_WaitForConnect(statePtr, &errorCode) < 0) {
		if (errorCode == EAGAIN) {
			dprintf("Async flag could be set (didn't check) and errorCode == EAGAIN:  Returning 0");

			return 0;
		}

		dprintf("Tls_WaitForConnect returned an error");
	}


	dprintf("Returning %i", mask);

	return(mask);
}

#if 0
/*
 *------------------------------------------------------*
 *
 *      TlsChannelHandler --

 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */


static void TlsChannelHandlerTimer(ClientData clientData) {


	State *statePtr = (State *) clientData;
	int mask = 0;

	dprintf("Called");

	statePtr->timer = (Tcl_TimerToken) NULL;

	if (BIO_wpending(statePtr->bio)) {
		dprintf("[chan=%p] BIO writable", statePtr->self);

		mask |= TCL_WRITABLE;
	}

	if (BIO_pending(statePtr->bio)) {
		dprintf("[chan=%p] BIO readable", statePtr->self);

		mask |= TCL_READABLE;
	}

	dprintf("Notifying ourselves");
	Tcl_NotifyChannel(statePtr->self, mask);

	dprintf("Returning");

	return;
}

/*
 *------------------------------------------------------*
 *
 *	Tls_WaitForConnect --
 *
 *	Sideeffects:
 *		Issues SSL_accept or SSL_connect
 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */
int Tls_WaitForConnect(State *statePtr, int *errorCodePtr) {
	unsigned long backingError;
	int err, rc;
	int bioShouldRetry;

	dprintf("WaitForConnect(%p)", (void *) statePtr);
	dprintFlags(statePtr);

	if (!(statePtr->flags & TLS_TCL_INIT)) {
		dprintf("Tls_WaitForConnect called on already initialized channel -- returning with immediate success");
		*errorCodePtr = 0;
		return(0);
	}

	if (statePtr->flags & TLS_TCL_HANDSHAKE_FAILED) {
		/*
		 * We choose ECONNRESET over ECONNABORTED here because some server
		 * side code, on the wiki for example, sets up a read handler that
		 * does a read and if eof closes the channel. There is no catch/try
		 * around the reads so exceptions will result in potentially many
		 * dangling channels hanging around that should have been closed.
		 * (Backgroun: ECONNABORTED maps to a Tcl exception and 
		 * ECONNRESET maps to graceful EOF).
		 */
		*errorCodePtr = ECONNRESET;
		return(-1);
	}

	for (;;) {
		/* Not initialized yet! */
		if (statePtr->flags & TLS_TCL_SERVER) {
			dprintf("Calling SSL_accept()");

			err = SSL_accept(statePtr->ssl);
		} else {
			dprintf("Calling SSL_connect()");

			err = SSL_connect(statePtr->ssl);
		}


		if (err > 0) {
			dprintf("That seems to have gone okay");

			err = BIO_flush(statePtr->bio);

			if (err <= 0) {
				dprintf("Flushing the lower layers failed, this will probably terminate this session");
			}
		}

		rc = SSL_get_error(statePtr->ssl, err);

		dprintf("Got error: %i (rc = %i)", err, rc);

		bioShouldRetry = 0;
		if (err <= 0) {
			if (rc == SSL_ERROR_WANT_CONNECT || rc == SSL_ERROR_WANT_ACCEPT || rc == SSL_ERROR_WANT_READ || rc == SSL_ERROR_WANT_WRITE) {
				bioShouldRetry = 1;
			} else if (BIO_should_retry(statePtr->bio)) {
				bioShouldRetry = 1;
			} else if (rc == SSL_ERROR_SYSCALL && Tcl_GetErrno() == EAGAIN) {
				bioShouldRetry = 1;
			}
		} else {

			if (!SSL_is_init_finished(statePtr->ssl)) {
				bioShouldRetry = 1;
			}
		}

		if (bioShouldRetry) {
			dprintf("The I/O did not complete -- but we should try it again");

			if (statePtr->flags & TLS_TCL_ASYNC) {
				dprintf("Returning EAGAIN so that it can be retried later");

				*errorCodePtr = EAGAIN;

				return(-1);
			} else {
				dprintf("Doing so now");

				continue;
			}
		}


		dprintf("We have either completely established the session or completely failed it -- there is no more need to ever retry it though");
		break;
	}


	*errorCodePtr = EINVAL;

	switch (rc) {
		case SSL_ERROR_NONE:
			/* The connection is up, we are done here */
			dprintf("The connection is up");
			break;
		case SSL_ERROR_ZERO_RETURN:
			dprintf("SSL_ERROR_ZERO_RETURN: Connect returned an invalid value...")
			return(-1);
		case SSL_ERROR_SYSCALL:
			backingError = ERR_get_error();
			dprintf("I/O error occured");

			if (backingError == 0 && err == 0) {
				dprintf("EOF reached")
			}

			statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
			*errorCodePtr = ECONNRESET;
			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);
		case SSL_ERROR_WANT_CONNECT:
		case SSL_ERROR_WANT_ACCEPT:
		case SSL_ERROR_WANT_X509_LOOKUP:
		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);
		if (err != X509_V_OK) {
			dprintf("Invalid certificate, returning in failure");

			Tls_Error(statePtr, (char *)X509_verify_cert_error_string(err));
			statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
			*errorCodePtr = ECONNABORTED;
			return(-1);
		}
	}
#endif

	dprintf("Removing the \"TLS_TCL_INIT\" flag since we have completed the handshake");

	statePtr->flags &= ~TLS_TCL_INIT;

	dprintf("Returning in success");

	*errorCodePtr = 0;

	return(0);
}

Tcl_Channel Tls_GetParent(State *statePtr, int maskFlags) {
	dprintf("Requested to get parent of channel %p", statePtr->self);

	if ((statePtr->flags & ~maskFlags) & TLS_TCL_FASTPATH) {
		dprintf("Asked to get the parent channel while we are using FastPath -- returning NULL");
		return(NULL);
	}

	return(Tcl_GetStackedChannel(statePtr->self));
}