*/

#include "tlsInt.h"
#include "tclOpts.h"
#include <stdlib.h>

/* Min OpenSSL version */
#if !defined(LIBRESSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER < 0x10101000L
#error "Only OpenSSL v1.1.1 or later is supported"
#endif

/*
 * External functions
 */

/*
 * Forward declarations
 */

#define F2N( key, dsp) \
	(((key) == NULL) ? (char *) NULL : \
		Tcl_TranslateFileName(interp, (key), (dsp)))
#define REASON()	ERR_reason_error_string(ERR_get_error())

static void	InfoCallback(const SSL *ssl, int where, int ret);

static Tcl_ObjCmdProc CiphersObjCmd;
static Tcl_ObjCmdProc HandshakeObjCmd;
static Tcl_ObjCmdProc ImportObjCmd;
static Tcl_ObjCmdProc StatusObjCmd;
static Tcl_ObjCmdProc VersionObjCmd;
static Tcl_ObjCmdProc MiscObjCmd;
static Tcl_ObjCmdProc UnimportObjCmd;

static SSL_CTX *CTX_Init(State *statePtr, int isServer, int proto, char *key,
			char *certfile, unsigned char *key_asn1, unsigned char *cert_asn1,
			int key_asn1_len, int cert_asn1_len, char *CAdir, char *CAfile,
      char *ciphers, char *DHparams);

static int	TlsLibInit(int uninitialize);

#define TLS_PROTO_SSL2		0x01
#define TLS_PROTO_SSL3		0x02
#define TLS_PROTO_TLS1		0x04
#define TLS_PROTO_TLS1_1	0x08


/*
 *-------------------------------------------------------------------
 *
 * 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_Obj *cmdPtr;

 *	    0			- the certificate is deemed invalid
 *	    1			- the certificate is deemed valid
 *	    empty string	- no change to certificate validation
 *
 * Side effects:
 *	The err field of the currently operative State is set
 *	  to a string describing the SSL negotiation failure reason

 *-------------------------------------------------------------------
 */
static int
VerifyCallback(int ok, X509_STORE_CTX *ctx)
{
    Tcl_Obj *cmdPtr, *result;
    char *errStr, *string;

 *	A standard Tcl result list.
 *
 * Side effects:
 *	constructs and destroys SSL context (CTX)
 *
 *-------------------------------------------------------------------
 */







static int
CiphersObjCmd(
    TCL_UNUSED(void *),
    Tcl_Interp *interp,
    int objc,
    Tcl_Obj	*const objv[])
{
    static const char *protocols[] = {
	"ssl2",	"ssl3",	"tls1",	"tls1.1", "tls1.2", "tls1.3", NULL
    };
    enum protocol {
	TLS_SSL2, TLS_SSL3, TLS_TLS1, TLS_TLS1_1, TLS_TLS1_2, TLS_TLS1_3, TLS_NONE
    };
    Tcl_Obj *objPtr;
    SSL_CTX *ctx = NULL;
    SSL *ssl = NULL;
    STACK_OF(SSL_CIPHER) *sk;

    char *cp, buf[BUFSIZ];
    int index, verbose = 0;

    dprintf("Called");

    if (objc < 2 || objc > 3) {
	Tcl_WrongNumArgs(interp, 1, objv, "protocol ?verbose?");
	return TCL_ERROR;
    }
    if (Tcl_GetIndexFromObj( interp, objv[1], protocols, "protocol", 0,
	&index) != TCL_OK) {
	return TCL_ERROR;
    }
    if (objc > 2 && Tcl_GetBooleanFromObj( interp, objv[2],
	&verbose) != TCL_OK) {
	return TCL_ERROR;
    }
    switch ((enum protocol)index) {
    case TLS_SSL2:
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
    case TLS_SSL3:
#if defined(NO_SSL3) || defined(OPENSSL_NO_SSL3) || defined(OPENSSL_NO_SSL3_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(SSLv3_method()); break;
#endif
    case TLS_TLS1:
#if defined(NO_TLS1) || defined(OPENSSL_NO_TLS1) || defined(OPENSSL_NO_TLS1_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(TLSv1_method()); break;
#endif
    case TLS_TLS1_1:
#if defined(NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(TLSv1_1_method()); break;
#endif
#if defined(NO_TLS1_2) || defined(OPENSSL_NO_TLS1_2) || defined(OPENSSL_NO_TLS1_2_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(TLSv1_2_method()); break;
#endif
#if defined(NO_TLS1_3) || defined(OPENSSL_NO_TLS1_3) || defined(OPENSSL_NO_TLS1_3_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(TLS_method()); break;
		SSL_CTX_set_min_proto_version (ctx, TLS1_3_VERSION);
		SSL_CTX_set_max_proto_version (ctx, TLS1_3_VERSION);
#endif
    default:
		break;
    }
    if (ctx == NULL) {
	Tcl_AppendResult(interp, REASON(), (char *) NULL);
	return TCL_ERROR;
    }
    ssl = SSL_new(ctx);
    if (ssl == NULL) {
	Tcl_AppendResult(interp, REASON(), (char *) NULL);
	SSL_CTX_free(ctx);
	return TCL_ERROR;
    }
    objPtr = Tcl_NewListObj( 0, NULL);

    if (!verbose) {
	for (index = 0; ; index++) {

	    Tcl_ListObjAppendElement( interp, objPtr,
		Tcl_NewStringObj( buf, -1) );
	}
    }
    SSL_free(ssl);
    SSL_CTX_free(ctx);

    Tcl_SetObjResult( interp, objPtr);
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * HandshakeObjCmd --

static int HandshakeObjCmd(
    TCL_UNUSED(void *),
    Tcl_Interp *interp,
    int objc,
    Tcl_Obj *const objv[])
{
	Tcl_Channel chan;		/* The channel to set a mode on. */
	State *statePtr;		/* client state for ssl socket */
	const char *errStr = NULL;
	int ret = 1;
	int err = 0;

	dprintf("Called");

	if (objc != 2) {
		Tcl_WrongNumArgs(interp, 1, objv, "channel");
		return(TCL_ERROR);
	}

	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", (char *)NULL);

		return(TCL_ERROR);
	}
	statePtr = (State *)Tcl_GetChannelInstanceData(chan);

	dprintf("Calling Tls_WaitForConnect");
	ret = Tls_WaitForConnect(statePtr, &err, 1);
	dprintf("Tls_WaitForConnect returned: %i", ret);

	if (
	    ret < 0 && \
	    ((statePtr->flags & TLS_TCL_ASYNC) && err == EAGAIN)
	) {
		dprintf("Async set and err = EAGAIN");
		ret = 0;
	} else if (ret < 0) {
		errStr = statePtr->err;
		Tcl_ResetResult(interp);
		Tcl_SetErrno(err);

		if (!errStr || *errStr == 0) {
			errStr = Tcl_PosixError(interp);
		}

		Tcl_AppendResult(interp, "handshake failed: ", errStr, (char *) NULL);
		dprintf("Returning TCL_ERROR with handshake failed: %s", errStr);
		return(TCL_ERROR);
	} else {
		if (err != 0) {
			dprintf("Got an error with a completed handshake: err = %i", err);
		}

		ret = 1;
	}

	dprintf("Returning TCL_OK with data \"%i\"", ret);
	Tcl_SetObjResult(interp, Tcl_NewIntObj(ret));
	return(TCL_OK);
}

/*
 *-------------------------------------------------------------------
 *
 * ImportObjCmd --
 *

    TCL_UNUSED(void *),
    Tcl_Interp *interp,
    int objc,
    Tcl_Obj *const objv[])
{
    Tcl_Channel chan;		/* The channel to set a mode on. */
    State *statePtr;		/* client state for ssl socket */
    SSL_CTX *ctx	        = NULL;
    Tcl_Obj *script	        = NULL;
    Tcl_Obj *password	        = NULL;
    Tcl_DString upperChannelTranslation, upperChannelBlocking, upperChannelEncoding, upperChannelEOFChar;
    int idx;
    Tcl_Size len;
    int flags		        = TLS_TCL_INIT;
    int server		        = 0;	/* is connection incoming or outgoing? */
    char *keyfile	        = NULL;
    char *certfile	        = NULL;
    unsigned char *key  	= NULL;
    Tcl_Size key_len        = 0;
    unsigned char *cert     = NULL;
    Tcl_Size cert_len       = 0;
    char *ciphers	        = NULL;
    char *CAfile	        = NULL;
    char *CAdir		        = NULL;
    char *DHparams	        = NULL;
    char *model		        = NULL;
#ifndef OPENSSL_NO_TLSEXT
    char *servername	        = NULL;	/* hostname for Server Name Indication */
#endif
    int ssl2 = 0, ssl3 = 0;
    int tls1 = 1, tls1_1 = 1, tls1_2 = 1, tls1_3 = 1;
    int proto = 0;
    int verify = 0, require = 0, request = 1;

    dprintf("Called");

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

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

	OPTSTR( "-cadir", CAdir);
	OPTSTR( "-cafile", CAfile);
	OPTSTR( "-certfile", certfile);
	OPTSTR( "-cipher", ciphers);
	OPTOBJ( "-command", script);
	OPTSTR( "-dhparams", DHparams);
	OPTSTR( "-keyfile", keyfile);
	OPTSTR( "-model", model);
	OPTOBJ( "-password", password);
	OPTBOOL( "-require", require);
	OPTBOOL( "-request", request);
	OPTBOOL( "-server", server);
#ifndef OPENSSL_NO_TLSEXT
        OPTSTR( "-servername", servername);
#endif

	OPTBOOL( "-ssl2", ssl2);
	OPTBOOL( "-ssl3", ssl3);
	OPTBOOL( "-tls1", tls1);
	OPTBOOL( "-tls1.1", tls1_1);
	OPTBOOL( "-tls1.2", tls1_2);
	OPTBOOL( "-tls1.3", tls1_3)
	OPTBYTE("-cert", cert, cert_len);
	OPTBYTE("-key", key, key_len);

	OPTBAD( "option", "-cadir, -cafile, -cert, -certfile, -cipher, -command, -dhparams, -key, -keyfile, -model, -password, -require, -request, -server, -servername, -ssl2, -ssl3, -tls1, -tls1.1, -tls1.2, or tls1.3");

	return TCL_ERROR;
    }
    if (request)	    verify |= SSL_VERIFY_CLIENT_ONCE | SSL_VERIFY_PEER;
    if (request && require) verify |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
    if (verify == 0)	verify = SSL_VERIFY_NONE;

	/* Get the "model" context */
	chan = Tcl_GetChannel(interp, model, &mode);
	if (chan == (Tcl_Channel) NULL) {
	    Tls_Free((void *)statePtr);
	    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", (char *)NULL);
	    Tls_Free((void *)statePtr);
	    return TCL_ERROR;
	}
	ctx = ((State *)Tcl_GetChannelInstanceData(chan))->ctx;
    } else {
	if ((ctx = CTX_Init(statePtr, server, proto, keyfile, certfile, key,
    cert, key_len, cert_len, CAdir, CAfile, ciphers,
    DHparams)) == (SSL_CTX*)0) {
	    Tls_Free((void *)statePtr);
	    return TCL_ERROR;
	}
    }

    statePtr->ctx = ctx;

    /*
     * SSL Initialization
     */

    statePtr->ssl = SSL_new(statePtr->ctx);
    if (!statePtr->ssl) {
	/* SSL library error */
	Tcl_AppendResult(interp, "couldn't construct ssl session: ", REASON(),
		(char *) NULL);
	Tls_Free((void *)statePtr);
	return TCL_ERROR;
    }

#ifndef OPENSSL_NO_TLSEXT
    if (servername) {
        if (!SSL_set_tlsext_host_name(statePtr->ssl, servername) && require) {
            Tcl_AppendResult(interp, "setting TLS host name extension failed",
                (char *) NULL);
            Tls_Free((void *)statePtr);
            return TCL_ERROR;
        }
    }
#endif

    /*
     * SSL Callbacks
     */

    SSL_set_app_data(statePtr->ssl, (void *)statePtr);	/* point back to us */

    SSL_set_verify(statePtr->ssl, verify, VerifyCallback);

    SSL_CTX_set_info_callback(statePtr->ctx, InfoCallback);

    /* Create Tcl_Channel BIO Handler */
    statePtr->p_bio	= BIO_new_tcl(statePtr, BIO_NOCLOSE);
    statePtr->bio	= BIO_new(BIO_f_ssl());

    if (server) {
	statePtr->flags |= TLS_TCL_SERVER;
	SSL_set_accept_state(statePtr->ssl);
    } else {
	SSL_set_connect_state(statePtr->ssl);
    }
    SSL_set_bio(statePtr->ssl, statePtr->p_bio, statePtr->p_bio);
    BIO_set_ssl(statePtr->bio, statePtr->ssl, BIO_NOCLOSE);

    /*
     * End of SSL Init
     */
    dprintf("Returning %s", Tcl_GetChannelName(statePtr->self));
    Tcl_SetResult(interp, (char *) Tcl_GetChannelName(statePtr->self),
	    TCL_VOLATILE);
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * UnimportObjCmd --

#if !defined(NO_TLS1_2) && !defined(OPENSSL_NO_TLS1_2) && !defined(OPENSSL_NO_TLS1_2_METHOD)
    case TLS_PROTO_TLS1_2:
	method = TLSv1_2_method ();
	break;
#endif
#if !defined(NO_TLS1_3) && !defined(OPENSSL_NO_TLS1_3) && !defined(OPENSSL_NO_TLS1_3_METHOD)
    case TLS_PROTO_TLS1_3:
        /*
         * The version range is constrained below,
         * after the context is created.  Use the
         * generic method here.
         */
	method = TLS_method ();
	break;
#endif
    default:
#ifdef HAVE_TLS_METHOD
        method = TLS_method ();
#else

#endif
	break;
    }

    ctx = SSL_CTX_new (method);

    if (!ctx) {
        return(NULL);
    }

#if !defined(NO_TLS1_3)
    if (proto == TLS_PROTO_TLS1_3) {
        SSL_CTX_set_min_proto_version (ctx, TLS1_3_VERSION);
        SSL_CTX_set_max_proto_version (ctx, TLS1_3_VERSION);
    }
#endif

    SSL_CTX_set_app_data( ctx, (void*)interp);	/* remember the interpreter */
    SSL_CTX_set_options( ctx, SSL_OP_ALL);	/* all SSL bug workarounds */
    SSL_CTX_set_options( ctx, off);	/* all SSL bug workarounds */
    SSL_CTX_sess_set_cache_size( ctx, 128);

    if (ciphers != NULL)
	SSL_CTX_set_cipher_list(ctx, ciphers);

    /* set some callbacks */
    SSL_CTX_set_default_passwd_cb(ctx, PasswordCallback);

#ifndef BSAFE
    SSL_CTX_set_default_passwd_cb_userdata(ctx, (void *)statePtr);
#endif

    /* read a Diffie-Hellman parameters file, or use the built-in one */
#ifdef OPENSSL_NO_DH
    if (DHparams != NULL) {
	Tcl_AppendResult(interp,
	    "DH parameter support not available", (char *) NULL);
	SSL_CTX_free(ctx);
	return NULL;
    }
#else
    {
	DH* dh;
	if (DHparams != NULL) {
	    BIO *bio;
	    Tcl_DStringInit(&ds);
	    bio = BIO_new_file(F2N(DHparams, &ds), "r");
	    if (!bio) {
		Tcl_DStringFree(&ds);
		Tcl_AppendResult(interp,
		    "Could not find DH parameters file", (char *) NULL);
		SSL_CTX_free(ctx);
		return NULL;
	    }

	    dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
	    BIO_free(bio);
	    Tcl_DStringFree(&ds);
	    if (!dh) {
		Tcl_AppendResult(interp,
		    "Could not read DH parameters from file", (char *) NULL);
		SSL_CTX_free(ctx);
		return NULL;
	    }
	} else {
	    dh = get_dhParams();
	}
	SSL_CTX_set_tmp_dh(ctx, dh);

	Tcl_DStringInit(&ds);

	if (SSL_CTX_use_certificate_file(ctx, F2N( certfile, &ds),
					SSL_FILETYPE_PEM) <= 0) {
	    Tcl_DStringFree(&ds);
	    Tcl_AppendResult(interp,
			     "unable to set certificate file ", certfile, ": ",
			     REASON(), (char *) NULL);
	    SSL_CTX_free(ctx);
	    return NULL;
	}
    } else if (cert != NULL) {
	load_private_key = 1;
	if (SSL_CTX_use_certificate_ASN1(ctx, cert_len, cert) <= 0) {
	    Tcl_DStringFree(&ds);
	    Tcl_AppendResult(interp,
			     "unable to set certificate: ",
			     REASON(), (char *) NULL);
	    SSL_CTX_free(ctx);
	    return NULL;
	}
    } else {
	certfile = (char*)X509_get_default_cert_file();

	if (SSL_CTX_use_certificate_file(ctx, certfile,
					SSL_FILETYPE_PEM) <= 0) {
#if 0
	    Tcl_DStringFree(&ds);
	    Tcl_AppendResult(interp,
			     "unable to use default certificate file ", certfile, ": ",
			     REASON(), (char *) NULL);
	    SSL_CTX_free(ctx);
	    return NULL;
#endif
	}
    }

    /* set our private key */

	    if (SSL_CTX_use_PrivateKey_file(ctx, F2N( keyfile, &ds), SSL_FILETYPE_PEM) <= 0) {
		Tcl_DStringFree(&ds);
		/* flush the passphrase which might be left in the result */
		Tcl_SetResult(interp, NULL, TCL_STATIC);
		Tcl_AppendResult(interp,
			         "unable to set public key file ", keyfile, " ",
			         REASON(), (char *) NULL);
		SSL_CTX_free(ctx);
		return NULL;
	    }

	    Tcl_DStringFree(&ds);
	} else if (key != NULL) {
	    if (SSL_CTX_use_PrivateKey_ASN1(EVP_PKEY_RSA, ctx, key,key_len) <= 0) {
		Tcl_DStringFree(&ds);
		/* flush the passphrase which might be left in the result */
		Tcl_SetResult(interp, NULL, TCL_STATIC);
		Tcl_AppendResult(interp,
		                 "unable to set public key: ",
		                 REASON(), (char *) NULL);
		SSL_CTX_free(ctx);
		return NULL;
	    }
	}
	/* Now we know that a key and cert have been set against
	 * the SSL context */
	if (!SSL_CTX_check_private_key(ctx)) {
	    Tcl_AppendResult(interp,
			     "private key does not match the certificate public key",
			     (char *) NULL);
	    SSL_CTX_free(ctx);
	    return NULL;
	}
    }

    /* Set verification CAs */
    Tcl_DStringInit(&ds);
    Tcl_DStringInit(&ds1);
    if (!SSL_CTX_load_verify_locations(ctx, F2N(CAfile, &ds), F2N(CAdir, &ds1)) ||
	!SSL_CTX_set_default_verify_paths(ctx)) {
#if 0
	Tcl_DStringFree(&ds);
	Tcl_DStringFree(&ds1);
	/* Don't currently care if this fails */
	Tcl_AppendResult(interp, "SSL default verify paths: ",
		REASON(), (char *) NULL);
	SSL_CTX_free(ctx);
	return NULL;
#endif
    }

    /* https://sourceforge.net/p/tls/bugs/57/ */
    /* XXX:TODO: Let the user supply values here instead of something that exists on the filesystem */

 *
 * Side effects:
 *	 create the ssl command, initialise ssl context
 *
 *-------------------------------------------------------------------
 */

DLLEXPORT int Tls_Init(Tcl_Interp *interp) {


	const char tlsTclInitScript[] = {
#include "tls.tcl.h"
            0x00
	};

        dprintf("Called");

	/*
	 * We only support Tcl 8.6 or newer
	 */
	if (
#ifdef USE_TCL_STUBS
	    Tcl_InitStubs(interp, "8.6-", 0)
#else
	    Tcl_PkgRequire(interp, "Tcl", "8.6-", 0)
#endif
	     == NULL) {
		return TCL_ERROR;
	}

	if (TlsLibInit(0) != TCL_OK) {
		Tcl_AppendResult(interp, "could not initialize SSL library", (char *)NULL);
		return TCL_ERROR;
	}

	Tcl_CreateObjCommand(interp, "tls::ciphers", CiphersObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::handshake", HandshakeObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::import", ImportObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::unimport", UnimportObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::status", StatusObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::version", VersionObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::misc", MiscObjCmd, NULL, 0);

	if (interp) {
		Tcl_Eval(interp, tlsTclInitScript);
	}

	return(Tcl_PkgProvide(interp, "tls", PACKAGE_VERSION));
}

/*
 *------------------------------------------------------*
 *
 *	Tls_SafeInit --
 *
 *	------------------------------------------------*
 *	Standard procedure required by 'load'.
 *	Initializes this extension for a safe interpreter.
 *	------------------------------------------------*
 *
 *	Sideeffects:
 *		As of 'Tls_Init'
 *
 *	Result:
 *		A standard Tcl error code.
 *
 *------------------------------------------------------*
 */

DLLEXPORT int Tls_SafeInit(Tcl_Interp *interp) {
	dprintf("Called");
	return(Tls_Init(interp));
}

/*
 *------------------------------------------------------*
 *
 *	TlsLibInit --
 *
 *	------------------------------------------------*
 *	Initializes SSL library once per application
 *	------------------------------------------------*
 *
 *	Side effects:
 *		initilizes SSL library
 *
 *	Result:
 *		none
 *
 *------------------------------------------------------*
 */
static int TlsLibInit(int uninitialize) {
	static int initialized = 0;
	int status = TCL_OK;
#if defined(OPENSSL_THREADS) && defined(TCL_THREADS)
	size_t num_locks;
#endif

	if (uninitialize) {
		if (!initialized) {
			dprintf("Asked to uninitialize, but we are not initialized");

			return(TCL_OK);
		}

		dprintf("Asked to uninitialize");

#if defined(OPENSSL_THREADS) && defined(TCL_THREADS)
		Tcl_MutexLock(&init_mx);

		CRYPTO_set_locking_callback(NULL);
		CRYPTO_set_id_callback(NULL);

		if (locks) {
			free(locks);
			locks = NULL;
			locksCount = 0;
		}
#endif
		initialized = 0;

#if defined(OPENSSL_THREADS) && defined(TCL_THREADS)
		Tcl_MutexUnlock(&init_mx);
#endif

		return(TCL_OK);
	}

	if (initialized) {
		dprintf("Called, but using cached value");
		return(status);
	}

	dprintf("Called");

#if defined(OPENSSL_THREADS) && defined(TCL_THREADS)
	Tcl_MutexLock(&init_mx);
#endif
	initialized = 1;

#if defined(OPENSSL_THREADS) && defined(TCL_THREADS)
	num_locks = CRYPTO_num_locks();
	locksCount = num_locks;
	locks = malloc(sizeof(*locks) * num_locks);
	memset(locks, 0, sizeof(*locks) * num_locks);

	CRYPTO_set_locking_callback(CryptoThreadLockCallback);
	CRYPTO_set_id_callback(CryptoThreadIdCallback);
#endif

	if (SSL_library_init() != 1) {
		status = TCL_ERROR;
		goto done;
	}

	SSL_load_error_strings();
	ERR_load_crypto_strings();

	BIO_new_tcl(NULL, 0);

done:
#if defined(OPENSSL_THREADS) && defined(TCL_THREADS)
	Tcl_MutexUnlock(&init_mx);
#endif

	return(status);
}

 * to enhance it to support full fileevent semantics.
 *
 * Also work done by the follow people provided the impetus to do this "right":-
 *	tclSSL (Colin McCormack, Shared Technology)
 *	SSLtcl (Peter Antman)
 *
 */

#ifndef _TLS_H
#define _TLS_H

#include <tcl.h>

/*
 * Initialization routines -- our entire public C API.

/*
 * Copyright (C) 1997-2000 Matt Newman <[email protected]>
 *
 * Provides BIO layer to interface openssl to Tcl.
 */

#include "tlsInt.h"

#ifdef TCLTLS_OPENSSL_PRE_1_1_API
#define BIO_get_data(bio)                ((bio)->ptr)
#define BIO_get_init(bio)                ((bio)->init)

static int BioWrite (BIO *h, const char *buf, int num);
static int BioRead  (BIO *h, char *buf, int num);
static int BioPuts  (BIO *h, const char *str);
static long BioCtrl (BIO *h, int cmd, long arg1, void *ptr);
static int BioNew   (BIO *h);
static int BioFree  (BIO *h);

BIO *BIO_new_tcl(State *statePtr, int flags) {



	BIO *bio;
	static BIO_METHOD *BioMethods = NULL;
#ifdef TCLTLS_SSL_USE_FASTPATH
	Tcl_Channel parentChannel;
	const Tcl_ChannelType *parentChannelType;
	void *parentChannelFdIn_p, *parentChannelFdOut_p;
	int parentChannelFdIn, parentChannelFdOut, parentChannelFd;
	int validParentChannelFd;
	int tclGetChannelHandleRet;
#endif

	dprintf("BIO_new_tcl() called");

	if (BioMethods == NULL) {
		BioMethods = BIO_meth_new(BIO_TYPE_TCL, "tcl");
		BIO_meth_set_write(BioMethods, BioWrite);
		BIO_meth_set_read(BioMethods, BioRead);
		BIO_meth_set_puts(BioMethods, BioPuts);
		BIO_meth_set_ctrl(BioMethods, BioCtrl);
		BIO_meth_set_create(BioMethods, BioNew);
		BIO_meth_set_destroy(BioMethods, BioFree);
	}

	if (statePtr == NULL) {
		dprintf("Asked to setup a NULL state, just creating the initial configuration");

		return(NULL);
	}

#ifdef TCLTLS_SSL_USE_FASTPATH
	/*
	 * If the channel can be mapped back to a file descriptor, just use the file descriptor
	 * with the SSL library since it will likely be optimized for this.
	 */
	parentChannel = Tls_GetParent(statePtr, 0);
	parentChannelType = Tcl_GetChannelType(parentChannel);

	validParentChannelFd = 0;
	if (strcmp(parentChannelType->typeName, "tcp") == 0) {
		tclGetChannelHandleRet = Tcl_GetChannelHandle(parentChannel, TCL_READABLE, &parentChannelFdIn_p);
		if (tclGetChannelHandleRet == TCL_OK) {
			tclGetChannelHandleRet = Tcl_GetChannelHandle(parentChannel, TCL_WRITABLE, &parentChannelFdOut_p);
			if (tclGetChannelHandleRet == TCL_OK) {
				parentChannelFdIn = PTR2INT(parentChannelFdIn_p);
				parentChannelFdOut = PTR2INT(parentChannelFdOut_p);
				if (parentChannelFdIn == parentChannelFdOut) {
					parentChannelFd = parentChannelFdIn;
					validParentChannelFd = 1;
				}
			}
		}
	}

	if (validParentChannelFd) {
		dprintf("We found a shortcut, this channel is backed by a socket: %i", parentChannelFdIn);
		bio = BIO_new_socket(parentChannelFd, flags);
		statePtr->flags |= TLS_TCL_FASTPATH;
		return(bio);
	}

	dprintf("Falling back to Tcl I/O for this channel");
#endif

	bio = BIO_new(BioMethods);
	BIO_set_data(bio, statePtr);
	BIO_set_shutdown(bio, flags);
	BIO_set_init(bio, 1);

	return(bio);
}

static int BioWrite(BIO *bio, const char *buf, int bufLen) {
	Tcl_Channel chan;
	int ret;
	int tclEofChan, tclErrno;

	chan = Tls_GetParent((State *) BIO_get_data(bio), 0);

	dprintf("[chan=%p] BioWrite(%p, <buf>, %d)", (void *)chan, (void *) bio, bufLen);

	ret = Tcl_WriteRaw(chan, buf, bufLen);

	tclEofChan = Tcl_Eof(chan);
	tclErrno = Tcl_GetErrno();

	dprintf("[chan=%p] BioWrite(%d) -> %d [tclEof=%d; tclErrno=%d]", (void *) chan, bufLen, ret, tclEofChan, Tcl_GetErrno());

	BIO_clear_flags(bio, BIO_FLAGS_WRITE | BIO_FLAGS_SHOULD_RETRY);

	if (tclEofChan && ret <= 0) {
		dprintf("Got EOF while reading, returning a Connection Reset error which maps to Soft EOF");
		Tcl_SetErrno(ECONNRESET);
		ret = 0;
	} else if (ret == 0) {
		dprintf("Got 0 from Tcl_WriteRaw, and EOF is not set; ret = 0");
		dprintf("Setting retry read flag");
		BIO_set_retry_read(bio);
	} else if (ret < 0) {
		dprintf("We got some kind of I/O error");

		if (tclErrno == EAGAIN) {
			dprintf("It's EAGAIN");
		} else {
			dprintf("It's an unepxected error: %s/%i", Tcl_ErrnoMsg(tclErrno), tclErrno);
		}
	} else {
		dprintf("Successfully wrote some data");
	}

	if (ret != -1 || (ret == -1 && tclErrno == EAGAIN)) {
		if (BIO_should_read(bio)) {
			dprintf("Setting should retry read flag");

			BIO_set_retry_read(bio);
		}
	}

	return(ret);
}


static int BioRead(BIO *bio, char *buf, int bufLen) {
	Tcl_Channel chan;
	int ret = 0;
	int tclEofChan, tclErrno;

	chan = Tls_GetParent((State *) BIO_get_data(bio), 0);

	dprintf("[chan=%p] BioRead(%p, <buf>, %d)", (void *) chan, (void *) bio, bufLen);

	if (buf == NULL) {
		return 0;
	}

	ret = Tcl_ReadRaw(chan, buf, bufLen);

	tclEofChan = Tcl_Eof(chan);
	tclErrno = Tcl_GetErrno();

	dprintf("[chan=%p] BioRead(%d) -> %d [tclEof=%d; tclErrno=%d]", (void *) chan, bufLen, ret, tclEofChan, tclErrno);

	BIO_clear_flags(bio, BIO_FLAGS_READ | BIO_FLAGS_SHOULD_RETRY);

	if (tclEofChan && ret <= 0) {
		dprintf("Got EOF while reading, returning a Connection Reset error which maps to Soft EOF");
		Tcl_SetErrno(ECONNRESET);
		ret = 0;
	} else if (ret == 0) {
		dprintf("Got 0 from Tcl_Read or Tcl_ReadRaw, and EOF is not set; ret = 0");
		dprintf("Setting retry read flag");
		BIO_set_retry_read(bio);
	} else if (ret < 0) {
		dprintf("We got some kind of I/O error");

		if (tclErrno == EAGAIN) {
			dprintf("It's EAGAIN");
		} else {
			dprintf("It's an unepxected error: %s/%i", Tcl_ErrnoMsg(tclErrno), tclErrno);
		}
	} else {
		dprintf("Successfully read some data");
	}

	if (ret != -1 || (ret == -1 && tclErrno == EAGAIN)) {
		if (BIO_should_write(bio)) {
			dprintf("Setting should retry write flag");

			BIO_set_retry_write(bio);
		}
	}

	dprintf("BioRead(%p, <buf>, %d) [%p] returning %i", (void *) bio, bufLen, (void *) chan, ret);

	return(ret);
}

static int BioPuts(BIO *bio, const char *str) {
	dprintf("BioPuts(%p, <string:%p>) called", bio, str);

	return BioWrite(bio, str, (int) strlen(str));
}

static long BioCtrl(BIO *bio, int cmd, long num, void *ptr) {
	Tcl_Channel chan;
	long ret = 1;

	chan = Tls_GetParent((State *) BIO_get_data(bio), 0);

	dprintf("BioCtrl(%p, 0x%x, 0x%lx, %p)", bio, cmd, num, ptr);

	switch (cmd) {
		case BIO_CTRL_RESET:
			dprintf("Got BIO_CTRL_RESET");
			ret = 0;
			break;
		case BIO_C_FILE_SEEK:
			dprintf("Got BIO_C_FILE_SEEK");
			ret = 0;
			break;
		case BIO_C_FILE_TELL:
			dprintf("Got BIO_C_FILE_TELL");
			ret = 0;
			break;
		case BIO_CTRL_INFO:
			dprintf("Got BIO_CTRL_INFO");
			ret = 1;
			break;
		case BIO_C_SET_FD:
			dprintf("Unsupported call: BIO_C_SET_FD");
			ret = -1;
			break;
		case BIO_C_GET_FD:
			dprintf("Unsupported call: BIO_C_GET_FD");
			ret = -1;
			break;
		case BIO_CTRL_GET_CLOSE:
			dprintf("Got BIO_CTRL_CLOSE");
			ret = BIO_get_shutdown(bio);
			break;
		case BIO_CTRL_SET_CLOSE:
			dprintf("Got BIO_SET_CLOSE");
			BIO_set_shutdown(bio, num);
			break;
		case BIO_CTRL_EOF:
			dprintf("Got BIO_CTRL_EOF");
			ret = Tcl_Eof(chan);
			break;
		case BIO_CTRL_PENDING:
			dprintf("Got BIO_CTRL_PENDING");
			ret = ((chan) ? Tcl_InputBuffered(chan) : 0);
			dprintf("BIO_CTRL_PENDING(%d)", (int) ret);
			break;
		case BIO_CTRL_WPENDING:
			dprintf("Got BIO_CTRL_WPENDING");
			ret = 0;
			break;
		case BIO_CTRL_DUP:
			dprintf("Got BIO_CTRL_DUP");
			break;
		case BIO_CTRL_FLUSH:
			dprintf("Got BIO_CTRL_FLUSH");
			ret = ((Tcl_WriteRaw(chan, "", 0) >= 0) ? 1 : -1);
			dprintf("BIO_CTRL_FLUSH returning value %li", ret);
			break;
#ifdef BIO_CTRL_GET_KTLS_SEND
		case BIO_CTRL_GET_KTLS_SEND:
			dprintf("Got BIO_CTRL_GET_KTLS_SEND");
			ret = 0;
			break;
#endif
#ifdef BIO_CTRL_GET_KTLS_RECV
		case BIO_CTRL_GET_KTLS_RECV:
			dprintf("Got BIO_CTRL_GET_KTLS_RECV");
			ret = 0;
			break;
#endif
		default:
			dprintf("Got unknown control command (%i)", cmd);
			ret = -2;
			break;
	}

	return(ret);
}

static int BioNew(BIO *bio) {
	dprintf("BioNew(%p) called", bio);

	BIO_set_init(bio, 0);
	BIO_set_data(bio, NULL);
	BIO_clear_flags(bio, -1);

	return(1);
}

static int BioFree(BIO *bio) {
	if (bio == NULL) {
		return(0);
	}

	dprintf("BioFree(%p) called", bio);

	if (BIO_get_shutdown(bio)) {
		if (BIO_get_init(bio)) {
			/*shutdown(bio->num, 2) */
			/*closesocket(bio->num) */
		}

		BIO_set_init(bio, 0);
		BIO_clear_flags(bio, -1);
	}

	return(1);
}

 * This was built from scratch based upon observation of OpenSSL 0.9.2B
 *
 * Addition credit is due for Andreas Kupries ([email protected]), for
 * providing the Tcl_ReplaceChannel mechanism and working closely with me
 * to enhance it to support full fileevent semantics.
 *
 * Also work done by the follow people provided the impetus to do this "right":
 *	tclSSL (Colin McCormack, Shared Technology)
 *	SSLtcl (Peter Antman)
 *
 */

#include "tlsInt.h"

/*
 * Forward declarations
 */
static int  TlsBlockModeProc (void *instanceData, int mode);
static int  TlsCloseProc (void *instanceData, Tcl_Interp *interp);
static int  TlsClose2Proc (void *instanceData, Tcl_Interp *interp, int flags);
static int  TlsInputProc (void *instanceData, char *buf, int bufSize, int *errorCodePtr);
static int  TlsOutputProc (void *instanceData, const char *buf, int toWrite, int *errorCodePtr);
static int  TlsGetOptionProc (void *instanceData, Tcl_Interp *interp, const char *optionName, Tcl_DString *dsPtr);
static void TlsWatchProc (void *instanceData, int mask);
static int  TlsGetHandleProc (void *instanceData, int direction, void **handlePtr);
static int  TlsNotifyProc (void *instanceData, int mask);
static void TlsChannelHandlerTimer (void *clientData);

/*
 * TLS Channel Type
 */
static const Tcl_ChannelType tlsChannelType = {
  "tls",                             /* typeName                             */
  TCL_CHANNEL_VERSION_5,             /* version                              */
  TlsCloseProc,                      /* closeProc                            */
  TlsInputProc,                      /* inputProc                            */
  TlsOutputProc,                     /* outputProc                           */
  0,                                 /* seekProc                             */
  0,                                 /* setOptionProc                        */
  TlsGetOptionProc,                  /* getOptionProc                        */
  TlsWatchProc,                      /* watchProc                            */
  TlsGetHandleProc,                  /* getHandleProc                        */
  TlsClose2Proc,                     /* close2Proc                           */
  TlsBlockModeProc,                  /* blockModeProc                        */
  0,                                 /* flushProc                            */
  TlsNotifyProc,                     /* handlerProc                          */
  0,                                 /* wideSeekProc                         */
  0,                                 /* threadActionProc                     */
  0                                  /* truncateProc                         */
};


/*
 *-------------------------------------------------------------------
 *
 * Tls_ChannelType --
 *
 *	Return the correct TLS channel driver info
 *
 * Results:
 *	The correct channel driver for the current version of Tcl.
 *
 * Side effects:
 *	None.
 *
 *-------------------------------------------------------------------
 */
const Tcl_ChannelType *Tls_ChannelType(void) {
	return &tlsChannelType;
}

/*
 *-------------------------------------------------------------------
 *
 * TlsBlockModeProc --
 *
 *	This procedure is invoked by the generic IO level
 *       to set blocking and nonblocking modes

 * Results:
 *	0 if successful, errno when failed.
 *
 * 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);
}

/*
 *-------------------------------------------------------------------
 *
 * TlsCloseProc --
 *
 *	This procedure is invoked by the generic IO level to perform
 *	channel-type-specific cleanup when a SSL socket based channel
 *	is closed.
 *
 *	Note: we leave the underlying socket alone, is this right?
 *
 * Results:
 *	0 if successful, the value of Tcl_GetErrno() if failed.
 *
 * Side effects:
 *	Closes the socket of the channel.
 *
 *-------------------------------------------------------------------
 */
static int TlsCloseProc(void *instanceData, TCL_UNUSED(Tcl_Interp *)) {



	State *statePtr = (State *) instanceData;

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

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

	dprintf("Returning TCL_OK");

	return(TCL_OK);
}





static int TlsClose2Proc(void *instanceData, Tcl_Interp *interp, int flags) {
	if (!(flags&(TCL_CLOSE_READ|TCL_CLOSE_WRITE))) {
	    return TlsCloseProc(instanceData, interp);
	}
	return EINVAL;
}

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

	dprintf("WaitForConnect(%p)", 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) {
		/*
		 * Different types of operations have different requirements
		 * SSL being established
		 */
		if (handshakeFailureIsPermanent) {
			dprintf("Asked to wait for a TLS handshake that has already failed.  Returning fatal error");
			*errorCodePtr = ECONNABORTED;
		} else {
			dprintf("Asked to wait for a TLS handshake that has already failed.  Returning soft error");
			*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();

			if (backingError == 0 && err == 0) {
				dprintf("EOF reached")
				*errorCodePtr = ECONNRESET;
			} else if (backingError == 0 && err == -1) {
				dprintf("I/O error occured (errno = %lu)", (unsigned long) Tcl_GetErrno());
				*errorCodePtr = Tcl_GetErrno();
				if (*errorCodePtr == ECONNRESET) {
					*errorCodePtr = ECONNABORTED;
				}
			} else {
				dprintf("I/O error occured (backingError = %lu)", backingError);
				*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);
		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);
}

/*
 *-------------------------------------------------------------------
 *
 * TlsInputProc --
 *
 *	This procedure is invoked by the generic IO level
 *       to read input from a SSL socket based channel.
 *
 * Results:
 *	The number of bytes read is returned or -1 on error. An output
 *	argument contains the POSIX error code on error, or zero if no
 *	error occurred.
 *
 * Side effects:
 *	Reads input from the input device of the channel.
 *
 *-------------------------------------------------------------------
 */

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);

	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, 0);
	if (tlsConnect < 0) {
		dprintf("Got an error waiting to connect (tlsConnect = %i, *errorCodePtr = %i)", tlsConnect, *errorCodePtr);

		bytesRead = -1;
		if (*errorCodePtr == ECONNRESET) {
			dprintf("Got connection reset");
			/* Soft EOF */
			*errorCodePtr = 0;
			bytesRead = 0;
		}

		return(bytesRead);
	}

	/*
	 * 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 0
	if (bytesRead <= 0) {
		if (BIO_should_retry(statePtr->bio)) {
			dprintf("I/O failed, will retry based on EAGAIN");
			*errorCodePtr = EAGAIN;
		}
	}
#endif

	switch (err) {
		case SSL_ERROR_NONE:
			dprintBuffer(buf, bytesRead);
			break;
		case SSL_ERROR_SSL:
			dprintf("SSL negotiation error, indicating that the connection has been aborted");

			Tls_Error(statePtr, TCLTLS_SSL_ERROR(statePtr->ssl, bytesRead));
			*errorCodePtr = ECONNABORTED;
			bytesRead = -1;

			break;
		case SSL_ERROR_SYSCALL:
			backingError = ERR_get_error();

			if (backingError == 0 && bytesRead == 0) {
				dprintf("EOF reached")
				*errorCodePtr = 0;
				bytesRead = 0;
			} else if (backingError == 0 && bytesRead == -1) {
				dprintf("I/O error occured (errno = %lu)", (unsigned long) Tcl_GetErrno());
				*errorCodePtr = Tcl_GetErrno();
				bytesRead = -1;
			} else {
				dprintf("I/O error occured (backingError = %lu)", backingError);
				*errorCodePtr = backingError;
				bytesRead = -1;
			}

			break;
		case SSL_ERROR_ZERO_RETURN:
			dprintf("Got SSL_ERROR_ZERO_RETURN, this means an EOF has been reached");
			bytesRead = 0;
			*errorCodePtr = 0;
			break;
		case SSL_ERROR_WANT_READ:
			dprintf("Got SSL_ERROR_WANT_READ, mapping this to EAGAIN");
			bytesRead = -1;
			*errorCodePtr = EAGAIN;
			break;
		default:
			dprintf("Unknown error (err = %i), mapping to EOF", err);
			*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(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);

	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");
	tlsConnect = Tls_WaitForConnect(statePtr, errorCodePtr, 1);
	if (tlsConnect < 0) {
		dprintf("Got an error waiting to connect (tlsConnect = %i, *errorCodePtr = %i)", tlsConnect, *errorCodePtr);

		written = -1;
		if (*errorCodePtr == ECONNRESET) {
			dprintf("Got connection reset");
			/* Soft EOF */
			*errorCodePtr = 0;
			written = 0;
		}

		return(written);
	}

	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("Got SSL_ERROR_WANT_WRITE, mapping it to EAGAIN");
			*errorCodePtr = EAGAIN;
			written = -1;
			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;
			*errorCodePtr = 0;
			break;
		case SSL_ERROR_SYSCALL:
			backingError = ERR_get_error();

			if (backingError == 0 && written == 0) {
				dprintf("EOF reached")
				*errorCodePtr = 0;
				written = 0;
			} else if (backingError == 0 && written == -1) {
				dprintf("I/O error occured (errno = %lu)", (unsigned long) Tcl_GetErrno());
				*errorCodePtr = Tcl_GetErrno();
				written = -1;
			} else {
				dprintf("I/O error occured (backingError = %lu)", backingError);
				*errorCodePtr = backingError;
				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 --
 *
 *	Computes 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
 *	list of all options and	their values is returned in the
 *	supplied DString.
 *
 * Side effects:
 *	None.
 *
 *-------------------------------------------------------------------
 */
static int

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 *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) {
        /*
         * 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_ERROR;
}

/*
 *-------------------------------------------------------------------
 *
 * TlsWatchProc --
 *
 *	Initialize the notifier to watch Tcl_Files from this channel.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Sets up the notifier so that a future event on the channel
 *	will be seen by Tcl.
 *
 *-------------------------------------------------------------------
 */

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

	if (mask & TCL_READABLE) {
		if (Tcl_InputBuffered(statePtr->self) > 0 || BIO_ctrl_pending(statePtr->bio) > 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, 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(void *instanceData, int direction, void **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(void *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, 1) < 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 --

 *		As of 'TlsChannelHandler'.
 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */










































static void TlsChannelHandlerTimer(void *clientData) {
	State *statePtr = (State *) clientData;
	int mask = 0;

	dprintf("Called");

#define _TLSINT_H

#include "tls.h"
#include <errno.h>
#include <string.h>
#include <stdint.h>

#ifdef __WIN32__
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <wincrypt.h> /* OpenSSL needs this on Windows */
#endif

#ifdef NO_PATENTS
#  define NO_IDEA

#ifndef ECONNRESET
#define ECONNRESET	131	/* Connection reset by peer */
#endif

#ifdef TCLEXT_TCLTLS_DEBUG
#include <ctype.h>
#define dprintf(...) { \
                       char dprintfBuffer[8192], *dprintfBuffer_p; \
                       dprintfBuffer_p = &dprintfBuffer[0]; \
                       dprintfBuffer_p += sprintf(dprintfBuffer_p, "%s:%i:%s():", __FILE__, __LINE__, __func__); \
                       dprintfBuffer_p += sprintf(dprintfBuffer_p, __VA_ARGS__); \
                       fprintf(stderr, "%s\n", dprintfBuffer); \
                     }
#define dprintBuffer(bufferName, bufferLength) { \
                                                 int dprintBufferIdx; \
                                                 unsigned char dprintBufferChar; \
                                                 fprintf(stderr, "%s:%i:%s():%s[%llu]={", __FILE__, __LINE__, __func__, #bufferName, (unsigned long long) bufferLength); \
                                                 for (dprintBufferIdx = 0; dprintBufferIdx < bufferLength; dprintBufferIdx++) { \
                                                         dprintBufferChar = bufferName[dprintBufferIdx]; \
                                                         if (isalpha(dprintBufferChar) || isdigit(dprintBufferChar)) { \
                                                                 fprintf(stderr, "'%c' ", dprintBufferChar); \
                                                         } else { \
                                                                 fprintf(stderr, "%02x ", (unsigned int) dprintBufferChar); \
                                                         }; \
                                                 }; \
                                                 fprintf(stderr, "}\n"); \
                                               }
#define dprintFlags(statePtr) { \
                                char dprintfBuffer[8192], *dprintfBuffer_p; \
                                dprintfBuffer_p = &dprintfBuffer[0]; \
                                dprintfBuffer_p += sprintf(dprintfBuffer_p, "%s:%i:%s():%s->flags=0", __FILE__, __LINE__, __func__, #statePtr); \
                                if (((statePtr)->flags & TLS_TCL_ASYNC) == TLS_TCL_ASYNC) { dprintfBuffer_p += sprintf(dprintfBuffer_p, "|TLS_TCL_ASYNC"); }; \
                                if (((statePtr)->flags & TLS_TCL_SERVER) == TLS_TCL_SERVER) { dprintfBuffer_p += sprintf(dprintfBuffer_p, "|TLS_TCL_SERVER"); }; \
                                if (((statePtr)->flags & TLS_TCL_INIT) == TLS_TCL_INIT) { dprintfBuffer_p += sprintf(dprintfBuffer_p, "|TLS_TCL_INIT"); }; \
                                if (((statePtr)->flags & TLS_TCL_DEBUG) == TLS_TCL_DEBUG) { dprintfBuffer_p += sprintf(dprintfBuffer_p, "|TLS_TCL_DEBUG"); }; \
                                if (((statePtr)->flags & TLS_TCL_CALLBACK) == TLS_TCL_CALLBACK) { dprintfBuffer_p += sprintf(dprintfBuffer_p, "|TLS_TCL_CALLBACK"); }; \
                                if (((statePtr)->flags & TLS_TCL_HANDSHAKE_FAILED) == TLS_TCL_HANDSHAKE_FAILED) { dprintfBuffer_p += sprintf(dprintfBuffer_p, "|TLS_TCL_HANDSHAKE_FAILED"); }; \
                                if (((statePtr)->flags & TLS_TCL_FASTPATH) == TLS_TCL_FASTPATH) { dprintfBuffer_p += sprintf(dprintfBuffer_p, "|TLS_TCL_FASTPATH"); }; \
                                fprintf(stderr, "%s\n", dprintfBuffer); \
                              }
#else
#define dprintf(...) if (0) { fprintf(stderr, __VA_ARGS__); }
#define dprintBuffer(bufferName, bufferLength) /**/
#define dprintFlags(statePtr) /**/
#endif

#define TCLTLS_SSL_ERROR(ssl,err) ((char*)ERR_reason_error_string((unsigned long)SSL_get_error((ssl),(err))))
/*
 * OpenSSL BIO Routines
 */
#define BIO_TYPE_TCL	(19|0x0400)

/*
 * Defines for State.flags
 */
#define TLS_TCL_ASYNC	(1<<0)	/* non-blocking mode */
#define TLS_TCL_SERVER	(1<<1)	/* Server-Side */
#define TLS_TCL_INIT	(1<<2)	/* Initializing connection */
#define TLS_TCL_DEBUG	(1<<3)	/* Show debug tracing */
#define TLS_TCL_CALLBACK	(1<<4)	/* In a callback, prevent update
					 * looping problem. [Bug 1652380] */
#define TLS_TCL_HANDSHAKE_FAILED (1<<5) /* Set on handshake failures and once
                                         * set, all further I/O will result
                                         * in ECONNABORTED errors. */
#define TLS_TCL_FASTPATH (1<<6)         /* The parent channel is being used directly by the SSL library */
#define TLS_TCL_DELAY (5)

/*
 * This structure describes the per-instance state
 * of an ssl channel.
 *
 * The SSL processing context is maintained here, in the ClientData
 */
typedef struct State {
	Tcl_Channel self;       /* this socket channel */
	Tcl_TimerToken timer;

	int flags;              /* see State.flags above  */
	int watchMask;          /* current WatchProc mask */
	int mode;               /* current mode of parent channel */

	Tcl_Interp *interp;     /* interpreter in which this resides */
	Tcl_Obj *callback;      /* script called for tracing, verifying and errors */
	Tcl_Obj *password;      /* script called for certificate password */

	int vflags;             /* verify flags */
	SSL *ssl;               /* Struct for SSL processing */
	SSL_CTX *ctx;           /* SSL Context */
	BIO *bio;               /* Struct for SSL processing */
	BIO *p_bio;             /* Parent BIO (that is layered on Tcl_Channel) */

	const char *err;
} State;

#ifdef USE_TCL_STUBS
#ifndef Tcl_StackChannel
#error "Unable to compile on this version of Tcl"

# else
#   define TCL_UNUSED(T) T JOIN(dummy, __LINE__)
# endif
#endif

#if (TCL_MAJOR_VERSION < 9) && defined(TCL_MINOR_VERSION) && (TCL_MINOR_VERSION < 7) && !defined(Tcl_Size)
#   define Tcl_Size int

#endif

/*
 * Forward declarations
 */
const Tcl_ChannelType *Tls_ChannelType(void);
Tcl_Channel     Tls_GetParent(State *statePtr, int maskFlags);

Tcl_Obj         *Tls_NewX509Obj(Tcl_Interp *interp, X509 *cert);
void            Tls_Error(State *statePtr, char *msg);
#if TCL_MAJOR_VERSION > 8
void            Tls_Free(void *blockPtr);
#else
void            Tls_Free(char *blockPtr);
#endif
void            Tls_Clean(State *statePtr);
int             Tls_WaitForConnect(State *statePtr, int *errorCodePtr, int handshakeFailureIsPermanent);

BIO             *BIO_new_tcl(State* statePtr, int flags);

#define PTR2INT(x) ((int) ((intptr_t) (x)))

#endif /* _TLSINT_H */

	Windows DLL Build instructions using nmake build system
	2020-10-15 [email protected]
	2023-08-22 Kevin Walzer ([email protected])

Properties:
- 64 bit DLL
- VisualStudio 2019
- WSL
- OpenSSL dynamically linked to TCLTLS DLL. We used a freely redistributable build of OpenSSL from https://www.firedaemon.com/firedaemon-openssl. Unzip and install OpenSSL in an accessible place (we used the lib subdirectory of our Tcl installation).

1. Visual Studio x64 native prompt. Update environmental variables for building Tcltls. Customize the below entries for your setup. 

set PATH=%PATH%;C:\tcl-trunk\lib\openssl-3\x64\bin
set INCLUDE=%INCLUDE%;C:\tcl-trunk\tcl\lib\openssl-3\x64\include\openssl
set LIB=%LIB%;C:\tcl-trunk\tcl\lib\openssl-3\x64\bin


2) Build TCLTLS