<dt><strong>state</strong> <em>state</em></dt>
        <dd>State of the connection: initializing, handshake, established</dd>
        <dt><strong>servername</strong> <em>name</em></dt>
        <dd>The name of the connected to server.</dd>
        <dt><strong>protocol</strong> <em>version</em></dt>
        <dd>The protocol version used for the connection:
	    SSL2, SSL3, TLS1, TLS1.1, TLS1.2, TLS1.3, or unknown.</dd>
        <dt><strong>renegotiation</strong> <em>state</em></dt>
        <dd>Whether protocol renegotiation is allowed or disallowed.</dd>
        <dt><strong>alpn</strong> <em>protocol</em></dt>
        <dd>The protocol selected after Application-Layer Protocol
	    Negotiation (ALPN).</dd>
        <dt><strong>securitylevel</strong> <em>level</em></dt>
        <dd>The security level used for selection of ciphers, key size, etc.</dd>
        <dt><strong>cipher</strong> <em>cipher</em></dt>
        <dd>The current cipher in use for the connection.</dd>
        <dt><strong>standard_name</strong> <em>name</em></dt>
        <dd>The standard RFC name of cipher.</dd>
        <dt><strong>bits</strong> <em>n</em></dt>
        <dd>The number of processed bits used for cipher.</dd>
        <dt><strong>secret_bits</strong> <em>n</em></dt>
        <dd>The number of secret bits used for cipher.</dd>
        <dt><strong>min_version</strong> <em>version</em></dt>
        <dd>The minimum protocol version for cipher.</dd>
        <dt><strong>description</strong> <em>string</em></dt>
        <dd>A text description of the cipher.</dd>





        <dt><strong>session_reused</strong> <em>boolean</em></dt>
        <dd>Whether the session has been reused or not.</dd>
        <dt><strong>session_id</strong> <em>string</em></dt>
        <dd>Unique session id for use in resuming the session.</dd>
        <dt><strong>session_ticket</strong> <em>string</em></dt>
        <dd>Unique session ticket for use in resuming the session.</dd>
        <dt><strong>resumable</strong> <em>boolean</em></dt>

static Tcl_Mutex *locks = NULL;
static int locksCount = 0;
static Tcl_Mutex init_mx;
#endif /* OPENSSL_THREADS */
#endif /* TCL_THREADS */

/********************/
/* Callbacks        */
/********************/


/*
 *-------------------------------------------------------------------
 *
 * InfoCallback --
 *
 *	monitors SSL connection process
 *
 * Results:
 *	None
 *
 * Side effects:
 *	Calls callback (if defined)
 *-------------------------------------------------------------------
 */
static void
InfoCallback(const SSL *ssl, int where, int ret) {
    State *statePtr = (State*)SSL_get_app_data((SSL *)ssl);
    Tcl_Interp *interp	= statePtr->interp;
    Tcl_Obj *cmdPtr;
    char *major; char *minor;

    dprintf("Called");

    if (statePtr->callback == (Tcl_Obj*)NULL)
	return;

	if (where & SSL_CB_READ)		minor = "read";
	else if (where & SSL_CB_WRITE)		minor = "write";
	else if (where & SSL_CB_LOOP)		minor = "loop";
	else if (where & SSL_CB_EXIT)		minor = "exit";
	else					minor = "unknown";
    }

    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj("info", -1));
    Tcl_ListObjAppendElement(interp, cmdPtr,
	    Tcl_NewStringObj(Tcl_GetChannelName(statePtr->self), -1));
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(major, -1));
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(minor, -1));

    if (where & (SSL_CB_LOOP|SSL_CB_EXIT)) {
	Tcl_ListObjAppendElement(interp, cmdPtr,
	    Tcl_NewStringObj(SSL_state_string_long(ssl), -1));
    } else if (where & SSL_CB_ALERT) {
	const char *cp = (char *) SSL_alert_desc_string_long(ret);

	Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(cp, -1));
    } else {
	Tcl_ListObjAppendElement(interp, cmdPtr,
	    Tcl_NewStringObj(SSL_state_string_long(ssl), -1));
    }
    Tcl_Preserve((ClientData) interp);
    Tcl_Preserve((ClientData) statePtr);

    Tcl_IncrRefCount(cmdPtr);
    (void) Tcl_EvalObjEx(interp, cmdPtr, TCL_EVAL_GLOBAL);
    Tcl_DecrRefCount(cmdPtr);

    Tcl_Release((ClientData) statePtr);
    Tcl_Release((ClientData) interp);
}

/*
 *-------------------------------------------------------------------
 *
 * VerifyCallback --
 *

VerifyCallback(int ok, X509_STORE_CTX *ctx) {
    Tcl_Obj *cmdPtr, *result;
    char *errStr, *string;
    int length;
    SSL   *ssl		= (SSL*)X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
    X509  *cert		= X509_STORE_CTX_get_current_cert(ctx);
    State *statePtr	= (State*)SSL_get_app_data(ssl);
    Tcl_Interp *interp	= statePtr->interp;
    int depth		= X509_STORE_CTX_get_error_depth(ctx);
    int err		= X509_STORE_CTX_get_error(ctx);
    int code;

    dprintf("Verify: %d", ok);

    if (!ok) {

	    return ok;
	} else {
	    return 1;
	}
    }
    cmdPtr = Tcl_DuplicateObj(statePtr->callback);

    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj("verify", -1));
    Tcl_ListObjAppendElement(interp, cmdPtr,
	    Tcl_NewStringObj(Tcl_GetChannelName(statePtr->self), -1));
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewIntObj(depth));
    Tcl_ListObjAppendElement(interp, cmdPtr, Tls_NewX509Obj(interp, cert));
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewIntObj(ok));
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(errStr ? errStr : "", -1));

    Tcl_Preserve((ClientData) interp);
    Tcl_Preserve((ClientData) statePtr);

    statePtr->flags |= TLS_TCL_CALLBACK;

    Tcl_IncrRefCount(cmdPtr);
    code = Tcl_EvalObjEx(interp, cmdPtr, TCL_EVAL_GLOBAL);
    if (code != TCL_OK) {
	/* It got an error - reject the certificate.		*/
#if (TCL_MAJOR_VERSION == 8) && (TCL_MINOR_VERSION < 6)
	Tcl_BackgroundError(interp);
#else
	Tcl_BackgroundException(interp, code);
#endif
	ok = 0;
    } else {
	result = Tcl_GetObjResult(interp);
	string = Tcl_GetStringFromObj(result, &length);
	/* An empty result leaves verification unchanged.	*/
	if (string != NULL && length > 0) {
	    code = Tcl_GetIntFromObj(interp, result, &ok);
	    if (code != TCL_OK) {
#if (TCL_MAJOR_VERSION == 8) && (TCL_MINOR_VERSION < 6)
		Tcl_BackgroundError(interp);
#else
		Tcl_BackgroundException(interp, code);
#endif
		ok = 0;
	    }
	}
    }
    Tcl_DecrRefCount(cmdPtr);

    statePtr->flags &= ~(TLS_TCL_CALLBACK);

    Tcl_Release((ClientData) statePtr);
    Tcl_Release((ClientData) interp);
    return(ok);	/* By default, leave verification unchanged.	*/
}

/*
 *-------------------------------------------------------------------
 *
 * Tls_Error --
 *
 *	Calls callback with $fd and $msg - so the callback can decide
 *	what to do with errors.
 *
 * Side effects:
 *	The err field of the currently operative State is set
 *	  to a string describing the SSL negotiation failure reason
 *-------------------------------------------------------------------
 */
void
Tls_Error(State *statePtr, char *msg) {
    Tcl_Interp *interp	= statePtr->interp;
    Tcl_Obj *cmdPtr;
    int code;

    dprintf("Called");

    if (msg && *msg) {
	Tcl_SetErrorCode(interp, "SSL", msg, (char *)NULL);
    } else {
	msg = Tcl_GetStringFromObj(Tcl_GetObjResult(interp), NULL);
    }
    statePtr->err = msg;

    if (statePtr->callback == (Tcl_Obj*)NULL) {
	char buf[BUFSIZ];
	sprintf(buf, "SSL channel \"%s\": error: %s",
	    Tcl_GetChannelName(statePtr->self), msg);
	Tcl_SetResult(interp, buf, TCL_VOLATILE);
#if (TCL_MAJOR_VERSION == 8) && (TCL_MINOR_VERSION < 6)
	Tcl_BackgroundError(interp);
#else
	Tcl_BackgroundException(interp, TCL_ERROR);
#endif
	return;
    }
    cmdPtr = Tcl_DuplicateObj(statePtr->callback);


    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj("error", -1));

    Tcl_ListObjAppendElement(interp, cmdPtr,
	    Tcl_NewStringObj(Tcl_GetChannelName(statePtr->self), -1));


    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(msg, -1));

    Tcl_Preserve((ClientData) interp);
    Tcl_Preserve((ClientData) statePtr);

    Tcl_IncrRefCount(cmdPtr);
    code = Tcl_EvalObjEx(interp, cmdPtr, TCL_EVAL_GLOBAL);
    if (code != TCL_OK) {
#if (TCL_MAJOR_VERSION == 8) && (TCL_MINOR_VERSION < 6)
	Tcl_BackgroundError(interp);
#else
	Tcl_BackgroundException(interp, code);
#endif
    }
    Tcl_DecrRefCount(cmdPtr);
    Tcl_Release((ClientData) statePtr);
    Tcl_Release((ClientData) interp);
}

/*
 *-------------------------------------------------------------------
 *
 * KeyLogCallback --
 *
 *	Write received key data to log file.
 *
 * Side effects:
 *	none
 *-------------------------------------------------------------------
 */
void KeyLogCallback(const SSL *ssl, const char *line) {
    char *str = getenv(SSLKEYLOGFILE);
    FILE *fd;
    if (str) {
	fd = fopen(str, "a");
	fprintf(fd, "%s\n",line);
	fclose(fd);

	return 0;

    cmdPtr = Tcl_DuplicateObj(statePtr->callback);

    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj( "session", -1));

    /* Session id */

    session_id = SSL_SESSION_get0_id_context(session, &len);
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(session_id, len));

    /* Session ticket */
    SSL_SESSION_get0_ticket(session, &ticket, &len2);
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(ticket, (int)len2));

    Tcl_DecrRefCount(cmdPtr);

    Tcl_Release((ClientData) statePtr);
    Tcl_Release((ClientData) interp);
    return 1;
}

/********************/
/* Commands         */
/********************/

/*
 *-------------------------------------------------------------------
 *
 * CiphersObjCmd -- list available ciphers
 *
 *	This procedure is invoked to process the "tls::ciphers" command
 *	to list available ciphers, based upon protocol selected.

    }

    chan = Tcl_GetChannel(interp, Tcl_GetStringFromObj(objv[1], NULL), NULL);
    if (chan == (Tcl_Channel) NULL) {
	return(TCL_ERROR);
    }


    /* Make sure to operate on the topmost channel */

    chan = Tcl_GetTopChannel(chan);
    if (Tcl_GetChannelType(chan) != Tls_ChannelType()) {
	Tcl_AppendResult(interp, "bad channel \"", Tcl_GetChannelName(chan), "\": not a TLS channel", NULL);
	return(TCL_ERROR);
    }
    statePtr = (State *)Tcl_GetChannelInstanceData(chan);

    }

    chan = Tcl_GetChannel(interp, Tcl_GetStringFromObj(objv[1], NULL), NULL);
    if (chan == (Tcl_Channel) NULL) {
	return TCL_ERROR;
    }


    /* Make sure to operate on the topmost channel */

    chan = Tcl_GetTopChannel(chan);

    for (idx = 2; idx < objc; idx++) {
	char *opt = Tcl_GetStringFromObj(objv[idx], NULL);

	if (opt[0] != '-')
	    break;

    }

    chan = Tcl_GetChannel(interp, Tcl_GetString(objv[1]), NULL);
    if (chan == (Tcl_Channel) NULL) {
	return TCL_ERROR;
    }


    /* Make sure to operate on the topmost channel */

    chan = Tcl_GetTopChannel(chan);

    if (Tcl_GetChannelType(chan) != Tls_ChannelType()) {
	Tcl_AppendResult(interp, "bad channel \"", Tcl_GetChannelName(chan),
		"\": not a TLS channel", NULL);
	return TCL_ERROR;
    }

	    return TCL_ERROR;
    }

    chan = Tcl_GetChannel(interp, channelName, &mode);
    if (chan == (Tcl_Channel) NULL) {
	return TCL_ERROR;
    }

    /* Make sure to operate on the topmost channel */

    chan = Tcl_GetTopChannel(chan);
    if (Tcl_GetChannelType(chan) != Tls_ChannelType()) {
	Tcl_AppendResult(interp, "bad channel \"", Tcl_GetChannelName(chan),
		"\": not a TLS channel", NULL);
	return TCL_ERROR;
    }
    statePtr = (State *) Tcl_GetChannelInstanceData(chan);

    }

    chan = Tcl_GetChannel(interp, Tcl_GetStringFromObj(objv[1], NULL), NULL);
    if (chan == (Tcl_Channel) NULL) {
	return(TCL_ERROR);
    }


    /* Make sure to operate on the topmost channel */

    chan = Tcl_GetTopChannel(chan);
    if (Tcl_GetChannelType(chan) != Tls_ChannelType()) {
	Tcl_AppendResult(interp, "bad channel \"", Tcl_GetChannelName(chan), "\": not a TLS channel", NULL);
	return(TCL_ERROR);
    }

    objPtr = Tcl_NewListObj(0, NULL);

    /* Connection info */
    statePtr = (State *)Tcl_GetChannelInstanceData(chan);
    ssl = statePtr->ssl;
    if (ssl != NULL) {
	const char *state;

	/* connection state */
	if (SSL_is_init_finished(ssl)) {
	    state = "established";
	} else if (SSL_in_init(ssl)) {
	    state = "handshake";
	} else {
	    state = "initializing";
	}
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("state", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj(state, -1));

	/* Get server name */
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("servername", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj(SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name), -1));

	/* Get protocol */
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("protocol", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj(SSL_get_version(ssl), -1));

	/* Renegotiation allowed */
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("renegotiation", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj(
	    SSL_get_secure_renegotiation_support(ssl) ? "allowed" : "not supported", -1));

	/* Report the selected protocol as a result of the ALPN negotiation */
	SSL_get0_alpn_selected(ssl, &proto, &len);
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("alpn", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj((char *)proto, (int)len));

	/* Get security level */
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("securitylevel", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewIntObj(SSL_get_security_level(ssl)));
    }

    /* Cipher info */
    cipher = SSL_get_current_cipher(ssl);
    if (cipher != NULL) {
	char buf[BUFSIZ] = {0};
	int bits, alg_bits;

	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("cipher", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj(SSL_CIPHER_get_name(cipher), -1));

	if (SSL_CIPHER_description(cipher, buf, sizeof(buf)) != NULL) {
	    Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("description", -1));
	    Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj(buf, -1));
	}
    }










    /* Session info */
    session = SSL_get_session(ssl);
    if (session != NULL) {
	const unsigned char *ticket;
	size_t len2;
	const unsigned char *session_id;

	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewLongObj(SSL_SESSION_get_timeout(session)));
    }

#if defined(HAVE_SSL_COMPRESSION)
    /* Compression info */
    comp = SSL_get_current_compression(ssl);
    if (comp != NULL) {

	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("compression", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj(SSL_COMP_get_name(comp), -1));
	comp = SSL_get_current_expansion(ssl);
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj("expansion", -1));
	Tcl_ListObjAppendElement(interp, objPtr, Tcl_NewStringObj(SSL_COMP_get_name(comp), -1));
    }
#endif

    Tcl_SetObjResult(interp, objPtr);
    return TCL_OK;
	clientData = clientData;
}

    default:
	break;
    }
    return TCL_OK;
	clientData = clientData;
}

/********************/
/* Init             */
/********************/

/*
 *-------------------------------------------------------------------
 *
 * Tls_Free --
 *
 *	This procedure cleans up when a SSL socket based channel
 *	is closed and its reference count falls below 1