<dd><b>tls::socket</b> <em> ?-server command? ?options? port</em></dd>
	    <dd><b>tls::handshake</b> <em> channel</em></dd>
	    <dd><b>tls::status </b> <em>?-local? channel</em></dd>
	    <dd><b>tls::connection </b> <em>channel</em></dd>
	    <dd><b>tls::import</b> <em>channel ?options?</em></dd>
	    <dd><b>tls::unimport</b> <em>channel</em></dd>
	    <dt>&nbsp;</dt>
	    <dd><b>tls::ciphers</b> <em>protocol ?verbose? ?supported?</em></dd>
	    <dd><b>tls::protocols</b></dd>
	    <dd><b>tls::version</b></dd>
	    <dt>&nbsp;</dt>
	    <dd><b>tls::hash</b> <em>type data</em></dd>
	    <dd><b>tls::md4</b> <em>data</em></dd>
	    <dd><b>tls::md5</b> <em>data</em></dd>
	    <dd><b>tls::sha1</b> <em>data</em></dd>
	    <dd><b>tls::sha256</b> <em>data</em></dd>
	</dl>
    </dd>
    <dd><a href="#COMMANDS">COMMANDS</a></dd>
    <dd><a href="#CALLBACK OPTIONS">CALLBACK OPTIONS</a></dd>
    <dd><a href="#HTTPS EXAMPLE">HTTPS EXAMPLE</a></dd>
    <dd><a href="#SEE ALSO">SPECIAL CONSIDERATIONS</a></dd>
    <dd><a href="#SEE ALSO">SEE ALSO</a></dd>
</dl>

<hr>

<h3><a name="NAME">NAME</a></h3>

<p><strong>tls</strong> - binding to <strong>OpenSSL</strong>
toolkit.</p>

<h3><a name="SYNOPSIS">SYNOPSIS</a></h3>

<p><b>package require Tcl 8.5</b><br>
<b>package require tls</b><br>
<br>
<a href="#tls::init"><b>tls::init</b> <i>?options?</i></a><br>
<a href="#tls::socket"><b>tls::socket</b> <i>?options? host port</i><br>
<a href="#tls::socket"><b>tls::socket</b> <i>?-server command? ?options? port</i></a><br>
<a href="#tls::status"><b>tls::status</b> <i>?-local? channel</i></a><br>
<a href="#tls::connection"><b>tls::connection</b> <i>channel</i></a><br>
<a href="#tls::handshake"><b>tls::handshake</b> <i>channel</i></a><br>
<a href="#tls::import"><b>tls::import</b> <i>channel ?options?</i></a><br>
<a href="#tls::unimport"><b>tls::unimport</b> <i>channel</i></a><br>
<br>
<a href="#tls::ciphers"><b>tls::ciphers</b> <i>protocol ?verbose? ?supported?</i></a><br>
<a href="#tls::protocols"><b>tls::protocols</b></a><br>
<a href="#tls::version"><b>tls::version</b></a><br>
<br>
<a href="#tls::hash"><b>tls::hash</b> <i>type data</i></a><br>
<a href="#tls::md4"><b>tls::md4</b> <i>data</i></a><br>
<a href="#tls::md5"><b>tls::md5</b> <i>data</i></a><br>
<a href="#tls::sha1"><b>tls::sha1</b> <i>data</i></a><br>
<a href="#tls::sha256"><b>tls::sha256</b> <i>data</i></a><br>
</p>

<h3><a name="DESCRIPTION">DESCRIPTION</a></h3>

<p>This extension provides a generic binding to <a
href="http://www.openssl.org/">OpenSSL</a>, utilizing the
<strong>Tcl_StackChannel</strong>

    <dd>Returns a list of supported protocols. Valid values are:
	<b>ssl2</b>, <b>ssl3</b>, <b>tls1</b>, <b>tls1.1</b>, <b>tls1.2</b>,
	and <b>tls1.3</b>. Exact list depends on OpenSSL version and
	compile time flags.</dd>

    <dt><a name="tls::version"><strong>tls::version</strong></a></dt>
    <dd>Returns the OpenSSL version string.</dd>

    <br>
    <dt><a name="tls::hash"><strong>tls::hash</strong> <em>type data</em></a></dt>
    <dd>Calculate the hash for <em>data</em> using <em>type</em> digest.
	Returns value as a hex string. Type cam be any OpenSSL supported
	hash digest including: <b>md4</b>, <b>md5</b>, <b>sha1</b>,
	sha2 (<b>sha224</b>, <b>sha256</b>, <b>sha384</b>, <b>sha512</b>,
	<b>sha512-224</b>, and <b>sha512-256</b>),
	sha3 (<b>sha3-224</b>, <b>sha3-256</b>, <b>sha3-384</b>, and <b>sha3-512</b>), etc.</dd>

    <dt><a name="tls::md4"><strong>tls::md4</strong> <em>data</em></a></dt>
    <dd>Calculate the hash for <em>data</em> using the MD4 message-digest algorithm.</dd>

    <dt><a name="tls::md5"><strong>tls::md5</strong> <em>data</em></a></dt>
    <dd>Calculate the hash for <em>data</em> using the MD5 message-digest algorithm.</dd>

    <dt><a name="tls::sha1"><strong>tls::sha1</strong> <em>data</em></a></dt>
    <dd>Calculate the hash for <em>data</em> using the SHA-1 secure hash algorithm.</dd>

    <dt><a name="tls::sha256"><strong>tls::sha256</strong> <em>data</em></a></dt>
    <dd>Calculate the hash for <em>data</em> using the SHA-2 SHA-256 secure hash algorithm.</dd>
</dl>

<h3><a name="CALLBACK OPTIONS">CALLBACK OPTIONS</a></h3>

<p>
As indicated above, individual channels can be given their own callbacks
to handle intermediate processing by the OpenSSL library, using the

    cmdPtr = Tcl_DuplicateObj(statePtr->callback);
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj("error", -1));
    Tcl_ListObjAppendElement(interp, cmdPtr,
	    Tcl_NewStringObj(Tcl_GetChannelName(statePtr->self), -1));
    if (msg != NULL) {
	Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(msg, -1));

    } else if ((msg = Tcl_GetStringFromObj(Tcl_GetObjResult(interp), NULL)) != NULL) {
	Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(msg, -1));

    } else {
	listPtr = Tcl_NewListObj(0, NULL);
	while ((err = ERR_get_error()) != 0) {
	    Tcl_ListObjAppendElement(interp, listPtr, Tcl_NewStringObj(ERR_reason_error_string(err), -1));
	}

    }
    Tcl_DecrRefCount(cmdPtr);

    Tcl_Release((ClientData) statePtr);

    /* If successful, pass back password string and truncate if too long */
    if (code == TCL_OK) {
	int len;
	char *ret = (char *) Tcl_GetStringFromObj(Tcl_GetObjResult(interp), &len);
	if (len > size-1) {
	    len = size-1;
	}
	strncpy(buf, ret, (size_t) len);
	buf[len] = '\0';
	Tcl_Release((ClientData) interp);
	return(len);
    }
    Tcl_Release((ClientData) interp);
    return -1;
}

/*
 *-------------------------------------------------------------------

    cmdPtr = Tcl_DuplicateObj(statePtr->callback);
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj("session", -1));
    Tcl_ListObjAppendElement(interp, cmdPtr,
	    Tcl_NewStringObj(Tcl_GetChannelName(statePtr->self), -1));

    /* Session id */
    session_id = SSL_SESSION_get_id(session, &ulen);
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewByteArrayObj(session_id, (int) ulen));

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

    /* Lifetime - number of seconds */
    Tcl_ListObjAppendElement(interp, cmdPtr,
	Tcl_NewLongObj((long) SSL_SESSION_get_ticket_lifetime_hint(session)));

    /* Eval callback command */
    Tcl_IncrRefCount(cmdPtr);

    servername = (const char *)p;

    /* Create command to eval */
    cmdPtr = Tcl_DuplicateObj(statePtr->vcmd);
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj("hello", -1));
    Tcl_ListObjAppendElement(interp, cmdPtr,
	    Tcl_NewStringObj(Tcl_GetChannelName(statePtr->self), -1));
    Tcl_ListObjAppendElement(interp, cmdPtr, Tcl_NewStringObj(servername, (int) len));

    /* Eval callback command */
    Tcl_IncrRefCount(cmdPtr);
    if ((code = EvalCallback(interp, statePtr, cmdPtr)) > 1) {
	res = SSL_CLIENT_HELLO_RETRY;
	*alert = SSL_R_TLSV1_ALERT_USER_CANCELLED;
    } else if (code == 1) {
	res = SSL_CLIENT_HELLO_SUCCESS;
    } else {
	res = SSL_CLIENT_HELLO_ERROR;
	*alert = SSL_R_TLSV1_ALERT_INTERNAL_ERROR;
    }
    Tcl_DecrRefCount(cmdPtr);
    return res;
}

/********************/
/* Commands         */
/********************/

/*
 *-------------------------------------------------------------------
 *
 * Hash Calc -- return hash hex string for message digest
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	None.
 *
 *-------------------------------------------------------------------
 */
int
HashCalc(Tcl_Interp *interp, int objc, Tcl_Obj *const objv[], const EVP_MD *type) {
    char *data;
    int len;
    unsigned int mdlen;
    unsigned char mdbuf[EVP_MAX_MD_SIZE];
    unsigned char hashbuf[EVP_MAX_MD_SIZE*2+1];
    const char *hex = "0123456789ABCDEF";

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

    data = Tcl_GetByteArrayFromObj(objv[1], &len);
    if (data == NULL) {
	return TCL_ERROR;
    }

    /* Calc hash, convert to hex string, and write to result */
    if (EVP_Digest(data, (size_t) len, mdbuf, &mdlen, type, NULL)) {
	unsigned char *mptr = mdbuf;
	unsigned char *hptr = &hashbuf[0];

	for (unsigned int i = 0; i < mdlen; i++) {
	    *hptr++ = hex[(*mptr>>4)&0xF];
	    *hptr++ = hex[(*mptr++)&0xF];
	}
	*hptr = 0;
	Tcl_SetObjResult(interp, Tcl_NewStringObj(hashbuf, mdlen*2));
    } else {
	Tcl_SetResult(interp, "Hash calculation error", NULL);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * Hash Commands -- Return hash hex string for message digest
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	None.
 *
 *-------------------------------------------------------------------
 */
HashCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    int len;
    const char *name;
    const EVP_MD *type;

    if (objc != 3) {
	Tcl_WrongNumArgs(interp, 1, objv, "type data");
	return TCL_ERROR;
    }

    name = Tcl_GetStringFromObj(objv[1],&len);
    if (name == NULL || (type = EVP_get_digestbyname(name)) == NULL) {
	Tcl_AppendResult(interp, "Invalid digest type \"", name, "\"", NULL);
	return TCL_ERROR;
    }
    objc--;
    objv++;
    return HashCalc(interp, objc, objv, type);
}

/*
 * Command to Calculate MD4 Hash
 */
int
HashMD4Cmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    return HashCalc(interp, objc, objv, EVP_md4());
}

/*
 * Command to Calculate MD5 Hash
 */
int
HashMD5Cmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    return HashCalc(interp, objc, objv, EVP_md5());
}

/*
 * Command to Calculate SHA-1 Hash
 */
int
HashSHA1Cmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    return HashCalc(interp, objc, objv, EVP_sha1());
}

/*
 * Command to Calculate SHA-256 Hash
 */
int
HashSHA256Cmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    return HashCalc(interp, objc, objv, EVP_sha256());
}

/*
 *-------------------------------------------------------------------
 *
 * CiphersObjCmd -- list available ciphers
 *
 *	This procedure is invoked to process the "tls::ciphers" command
 *	to list available ciphers, based upon protocol selected.

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

    ERR_clear_error();

    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_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_Obj *vcmd	        = NULL;
    Tcl_DString upperChannelTranslation, upperChannelBlocking, upperChannelEncoding, upperChannelEOFChar;
    int idx, len;

    int flags		        = TLS_TCL_INIT;
    int server		        = 0;	/* is connection incoming or outgoing? */
    char *keyfile	        = NULL;
    char *certfile	        = NULL;
    unsigned char *key  	= NULL;
    int key_len                 = 0;
    unsigned char *cert         = NULL;
    int cert_len                = 0;
    char *ciphers	        = NULL;
    char *ciphersuites	        = NULL;
    char *CAfile	        = NULL;
    char *CAdir		        = NULL;
    char *DHparams	        = NULL;
    char *model		        = NULL;
    char *servername	        = NULL;	/* hostname for Server Name Indication */

    if (objc < 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "channel ?options?");
	return TCL_ERROR;
    }

    ERR_clear_error();

    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;

	OPTOBJ("-alpn", alpn);
	OPTSTR("-cadir", CAdir);
	OPTSTR("-cafile", CAfile);

		"\": not a TLS channel", NULL);
	    Tcl_SetErrorCode(interp, "TLS", "IMPORT", "CHANNEL", "INVALID", (char *) NULL);
	    Tls_Free((char *) 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, ciphersuites, level, DHparams)) == NULL) {
	    Tls_Free((char *) statePtr);
	    return TCL_ERROR;
	}
    }

    statePtr->ctx = ctx;

    /* Enable Application-Layer Protocol Negotiation. Examples are: http/1.0,
	http/1.1, h2, h3, ftp, imap, pop3, xmpp-client, xmpp-server, mqtt, irc, etc. */
    if (alpn) {
	/* Convert a TCL list into a protocol-list in wire-format */
	unsigned char *protos, *p;
	unsigned int protos_len = 0;

	int i, len, cnt;
	Tcl_Obj **list;

	if (Tcl_ListObjGetElements(interp, alpn, &cnt, &list) != TCL_OK) {
	    Tls_Free((char *) statePtr);
	    return TCL_ERROR;
	}

	/* Determine the memory required for the protocol-list */
	for (i = 0; i < cnt; i++) {
	    Tcl_GetStringFromObj(list[i], &len);
	    if (len > 255) {
		Tcl_AppendResult(interp, "ALPN protocol name too long", (char *) NULL);
		Tcl_SetErrorCode(interp, "TLS", "IMPORT", "ALPN", "FAILED", (char *) NULL);
		Tls_Free((char *) statePtr);
		return TCL_ERROR;
	    }
	    protos_len += 1 + len;
	}

	/* Build the complete protocol-list */
	protos = ckalloc(protos_len);
	/* protocol-lists consist of 8-bit length-prefixed, byte strings */
	for (i = 0, p = protos; i < cnt; i++) {
	    char *str = Tcl_GetStringFromObj(list[i], &len);
	    *p++ = len;
	    memcpy(p, str, len);
	    p += len;
	}

	/* SSL_set_alpn_protos makes a copy of the protocol-list */
	/* Note: This functions reverses the return value convention */
	if (SSL_set_alpn_protos(statePtr->ssl, protos, protos_len)) {
	    Tcl_AppendResult(interp, "failed to set ALPN protocols", (char *) NULL);

    int off = 0;
    int load_private_key;
    const SSL_METHOD *method;

    dprintf("Called");

    if (!proto) {
	Tcl_AppendResult(interp, "no valid protocol selected", NULL);
	return NULL;
    }

    /* create SSL context */
#if OPENSSL_VERSION_NUMBER >= 0x10100000L || defined(NO_SSL2) || defined(OPENSSL_NO_SSL2)
    if (ENABLED(proto, TLS_PROTO_SSL2)) {
	Tcl_AppendResult(interp, "SSL2 protocol not supported", NULL);
	return NULL;
    }
#endif
#if defined(NO_SSL3) || defined(OPENSSL_NO_SSL3)
    if (ENABLED(proto, TLS_PROTO_SSL3)) {
	Tcl_AppendResult(interp, "SSL3 protocol not supported", NULL);
	return NULL;
    }
#endif
#if defined(NO_TLS1) || defined(OPENSSL_NO_TLS1)
    if (ENABLED(proto, TLS_PROTO_TLS1)) {
	Tcl_AppendResult(interp, "TLS 1.0 protocol not supported", NULL);
	return NULL;
    }
#endif
#if defined(NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1)
    if (ENABLED(proto, TLS_PROTO_TLS1_1)) {
	Tcl_AppendResult(interp, "TLS 1.1 protocol not supported", NULL);
	return NULL;
    }
#endif
#if defined(NO_TLS1_2) || defined(OPENSSL_NO_TLS1_2)
    if (ENABLED(proto, TLS_PROTO_TLS1_2)) {
	Tcl_AppendResult(interp, "TLS 1.2 protocol not supported", NULL);
	return NULL;
    }
#endif
#if defined(NO_TLS1_3) || defined(OPENSSL_NO_TLS1_3)
    if (ENABLED(proto, TLS_PROTO_TLS1_3)) {
	Tcl_AppendResult(interp, "TLS 1.3 protocol not supported", NULL);
	return NULL;
    }
#endif
    if (proto == 0) {
	/* Use full range */
	SSL_CTX_set_min_proto_version(ctx, 0);
	SSL_CTX_set_max_proto_version(ctx, 0);

    if (objc < 2 || objc > 3 || (objc == 3 && !strcmp(Tcl_GetString(objv[1]), "-local"))) {
	Tcl_WrongNumArgs(interp, 1, objv, "?-local? channel");
	return TCL_ERROR;
    }

    /* Get channel Id */
    channelName = Tcl_GetStringFromObj(objv[(objc == 2 ? 1 : 2)], NULL);
    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);

    }

    /* Verify mode depth */
    LAPPEND_INT(interp, objPtr, "verifyDepth", SSL_get_verify_depth(statePtr->ssl));

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

    /* Valid for non-RSA signature and TLS 1.3 */
    if (objc == 2) {
	res = SSL_get_peer_signature_nid(statePtr->ssl, &nid);
    } else {
	res = SSL_get_signature_nid(statePtr->ssl, &nid);

    const EVP_MD *md;

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

    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()) {

	size_t len2;
	unsigned int ulen;
	const unsigned char *session_id, *proto;
	char buffer[SSL_MAX_MASTER_KEY_LENGTH];

	/* Report the selected protocol as a result of the ALPN negotiation */
	SSL_SESSION_get0_alpn_selected(session, &proto, &len2);
	LAPPEND_STR(interp, objPtr, "alpn", (char *) proto, (int) len2);

	/* Report the selected protocol as a result of the NPN negotiation */
#ifdef USE_NPN
	SSL_get0_next_proto_negotiated(ssl, &proto, &ulen);
	LAPPEND_STR(interp, objPtr, "npn", (char *) proto, (int) ulen);
#endif

	/* Resumable session */
	LAPPEND_BOOL(interp, objPtr, "resumable", SSL_SESSION_is_resumable(session));

	/* Session start time (seconds since epoch) */
	LAPPEND_LONG(interp, objPtr, "start_time", SSL_SESSION_get_time(session));

	/* Timeout value - SSL_CTX_get_timeout (in seconds) */
	LAPPEND_LONG(interp, objPtr, "timeout", SSL_SESSION_get_timeout(session));

	/* Session id - TLSv1.2 and below only */
	session_id = SSL_SESSION_get_id(session, &ulen);
	LAPPEND_BARRAY(interp, objPtr, "session_id", session_id, (int) ulen);

	/* Session context */
	session_id = SSL_SESSION_get0_id_context(session, &ulen);
	LAPPEND_BARRAY(interp, objPtr, "session_context", session_id, (int) ulen);

	/* Session ticket - client only */
	SSL_SESSION_get0_ticket(session, &ticket, &len2);
	LAPPEND_BARRAY(interp, objPtr, "session_ticket", ticket, (int) len2);

	/* Session ticket lifetime hint (in seconds) */
	LAPPEND_LONG(interp, objPtr, "lifetime", SSL_SESSION_get_ticket_lifetime_hint(session));

	/* Ticket app data */
	SSL_SESSION_get0_ticket_appdata(session, &ticket, &len2);
	LAPPEND_BARRAY(interp, objPtr, "ticket_app_data", ticket, (int) len2);

	/* Get master key */
	len2 = SSL_SESSION_get_master_key(session, buffer, SSL_MAX_MASTER_KEY_LENGTH);
	LAPPEND_BARRAY(interp, objPtr, "master_key", buffer, (int) len2);

	/* Compression id */
	unsigned int id = SSL_SESSION_get_compress_id(session);
	LAPPEND_STR(interp, objPtr, "compression_id", id == 1 ? "zlib" : "none", -1);
    }

    /* Compression info */

 *
 *-------------------------------------------------------------------
 */
static int
MiscObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    static const char *commands [] = { "req", "strreq", NULL };
    enum command { C_REQ, C_STRREQ, C_DUMMY };

    int cmd, isStr;
    char buffer[16384];

    dprintf("Called");

    if (objc < 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "subcommand ?args?");
	return TCL_ERROR;

    switch ((enum command) cmd) {
	case C_REQ:
	case C_STRREQ: {
	    EVP_PKEY *pkey=NULL;
	    X509 *cert=NULL;
	    X509_NAME *name=NULL;
	    Tcl_Obj **listv;
	    int listc,i;


	    BIO *out=NULL;

	    char *k_C="",*k_ST="",*k_L="",*k_O="",*k_OU="",*k_CN="",*k_Email="";
	    char *keyout,*pemout,*str;
	    int keysize,serial=0,days=365;

	    pemout=Tcl_GetString(objv[4]);
	    if (isStr) {
		Tcl_SetVar(interp,keyout,"",0);
		Tcl_SetVar(interp,pemout,"",0);
	    }

	    if (objc>=6) {
		if (Tcl_ListObjGetElements(interp, objv[5],
			&listc, &listv) != TCL_OK) {
		    return TCL_ERROR;
		}

		if ((listc%2) != 0) {
		    Tcl_SetResult(interp,"Information list must have even number of arguments",NULL);
		    return TCL_ERROR;
		}

#endif
    if (Tcl_PkgRequire(interp, "Tcl", "8.5-", 0) == NULL) {
	return TCL_ERROR;
    }
#endif

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

    Tcl_CreateObjCommand(interp, "tls::ciphers", CiphersObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::connection", ConnectionInfoObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::handshake", HandshakeObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::import", ImportObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::unimport", UnimportObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::status", StatusObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::version", VersionObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::misc", MiscObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::protocols", ProtocolsObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);

    Tcl_CreateObjCommand(interp, "tls::hash", HashCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::md4", HashMD4Cmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::md5", HashMD5Cmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::sha1", HashSHA1Cmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::sha256", HashSHA256Cmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);

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

    return Tcl_PkgProvide(interp, PACKAGE_NAME, PACKAGE_VERSION);
}

/*
 * Copyright (C) 1997-2000 Matt Newman <matt@novadigm.com>
 *
 * Provides BIO layer to interface openssl to Tcl.
 */

#include "tlsInt.h"

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 = (int) 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;

    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;
    Tcl_Size 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;

	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));
}

#   endif
#endif

/*
 * Backwards compatibility for size type change
 */
#if TCL_MAJOR_VERSION < 9 && TCL_MINOR_VERSION < 7
#   define Tcl_Size int




#endif

#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#include <openssl/opensslv.h>

    int len = 0;
    char buffer[1024];

    if (astring != NULL) {
	len = String_to_Hex((char *)ASN1_STRING_get0_data(astring),
	    ASN1_STRING_length(astring), buffer, 1024);
    }
    resultPtr = Tcl_NewStringObj(buffer, len);
    return resultPtr;
}

/*
 * Get Key Usage
 */
Tcl_Obj *Tls_x509KeyUsage(Tcl_Interp *interp, X509 *cert, uint32_t xflags) {

    }

    if (names = X509_get_ext_d2i(cert, nid, NULL, NULL)) {
	for (int i=0; i < sk_GENERAL_NAME_num(names); i++) {
	    const GENERAL_NAME *name = sk_GENERAL_NAME_value(names, i);

	    len = BIO_to_Buffer(name && GENERAL_NAME_print(bio, name), bio, buffer, 1024);
	    LAPPEND_STR(interp, listPtr, NULL, buffer, len);
	}
	sk_GENERAL_NAME_pop_free(names, GENERAL_NAME_free);
    }
    return listPtr;
}

/*

	    if (distpoint->type == 0) {
		/* full-name GENERALIZEDNAME */
		for (int j = 0; j < sk_GENERAL_NAME_num(distpoint->name.fullname); j++) {
		    GENERAL_NAME *gen = sk_GENERAL_NAME_value(distpoint->name.fullname, j);
		    int type;
		    ASN1_STRING *uri = GENERAL_NAME_get0_value(gen, &type);
		    if (type == GEN_URI) {
			LAPPEND_STR(interp, listPtr, NULL, ASN1_STRING_get0_data(uri), ASN1_STRING_length(uri));
		    }
		}
	    } else if (distpoint->type == 1) {
		/* relative-name X509NAME */
		STACK_OF(X509_NAME_ENTRY) *sk_relname = distpoint->name.relativename;
		for (int j = 0; j < sk_X509_NAME_ENTRY_num(sk_relname); j++) {
		    X509_NAME_ENTRY *e = sk_X509_NAME_ENTRY_value(sk_relname, j);
		    ASN1_STRING *d = X509_NAME_ENTRY_get_data(e);
		    LAPPEND_STR(interp, listPtr, NULL, ASN1_STRING_data(d), ASN1_STRING_length(d));
		}
	    }
	}
	CRL_DIST_POINTS_free(crl);
    }
    return listPtr;
}

    if (ads = X509_get_ext_d2i(cert, NID_info_access, NULL, NULL)) {
	for (int i = 0; i < sk_ACCESS_DESCRIPTION_num(ads); i++) {
	    ad = sk_ACCESS_DESCRIPTION_value(ads, i);
	    if (OBJ_obj2nid(ad->method) == NID_ad_ca_issuers && ad->location) {
		if (ad->location->type == GEN_URI) {
		    len = ASN1_STRING_to_UTF8(&buf, ad->location->d.uniformResourceIdentifier);
		    Tcl_ListObjAppendElement(interp, listPtr, Tcl_NewStringObj(buf, len));
		    OPENSSL_free(buf);
		    break;
		}
	    }
	}
	/* sk_ACCESS_DESCRIPTION_pop_free(ads, ACCESS_DESCRIPTION_free); */
	AUTHORITY_INFO_ACCESS_free(ads);

	int sig_nid;

	X509_get0_signature(&sig, &sig_alg, cert);
	/* sig_nid = X509_get_signature_nid(cert) */
	sig_nid = OBJ_obj2nid(sig_alg->algorithm);
	LAPPEND_STR(interp, certPtr, "signatureAlgorithm", OBJ_nid2ln(sig_nid), -1);
	len = (sig_nid != NID_undef) ? String_to_Hex(sig->data, sig->length, buffer, BUFSIZ) : 0;
	LAPPEND_STR(interp, certPtr, "signatureValue", buffer, len);
    }

    /* Version of the encoded certificate - RFC 5280 section 4.1.2.1 */
    LAPPEND_LONG(interp, certPtr, "version", X509_get_version(cert)+1);

    /* Unique number assigned by CA to certificate - RFC 5280 section 4.1.2.2 */
    len = BIO_to_Buffer(i2a_ASN1_INTEGER(bio, X509_get0_serialNumber(cert)), bio, buffer, BUFSIZ);
    LAPPEND_STR(interp, certPtr, "serialNumber", buffer, len);

    /* Signature algorithm used by the CA to sign the certificate. Must match
	signatureAlgorithm. RFC 5280 section 4.1.2.3 */
    LAPPEND_STR(interp, certPtr, "signature", OBJ_nid2ln(X509_get_signature_nid(cert)), -1);

    /* Issuer identifies the entity that signed and issued the cert. RFC 5280 section 4.1.2.4 */
    len = BIO_to_Buffer(X509_NAME_print_ex(bio, X509_get_issuer_name(cert), 0, flags), bio, buffer, BUFSIZ);
    LAPPEND_STR(interp, certPtr, "issuer", buffer, len);

    /* Certificate validity period is the interval the CA warrants that it will
	maintain info on the status of the certificate. RFC 5280 section 4.1.2.5 */
    /* Get Validity - Not Before */
    len = BIO_to_Buffer(ASN1_TIME_print(bio, X509_get0_notBefore(cert)), bio, buffer, BUFSIZ);
    LAPPEND_STR(interp, certPtr, "notBefore", buffer, len);

    /* Get Validity - Not After */
    len = BIO_to_Buffer(ASN1_TIME_print(bio, X509_get0_notAfter(cert)), bio, buffer, BUFSIZ);
    LAPPEND_STR(interp, certPtr, "notAfter", buffer, len);

    /* Subject identifies the entity associated with the public key stored in
	the subject public key field. RFC 5280 section 4.1.2.6 */
    len = BIO_to_Buffer(X509_NAME_print_ex(bio, X509_get_subject_name(cert), 0, flags), bio, buffer, BUFSIZ);
    LAPPEND_STR(interp, certPtr, "subject", buffer, len);

    /* SHA1 Digest (Fingerprint) of cert - DER representation */
    if (X509_digest(cert, EVP_sha1(), md, &len)) {
    len = String_to_Hex(md, len, buffer, BUFSIZ);
	LAPPEND_STR(interp, certPtr, "sha1_hash", buffer, len);
    }

    /* SHA256 Digest (Fingerprint) of cert - DER representation */
    if (X509_digest(cert, EVP_sha256(), md, &len)) {
    len = String_to_Hex(md, len, buffer, BUFSIZ);
	LAPPEND_STR(interp, certPtr, "sha256_hash", buffer, len);
    }

    /* Subject Public Key Info specifies the public key and identifies the
	algorithm with which the key is used. RFC 5280 section 4.1.2.7 */
    if (X509_get_signature_info(cert, &mdnid, &pknid, &bits, &xflags)) {
	ASN1_BIT_STRING *key;
	unsigned int n;

	LAPPEND_STR(interp, certPtr, "signingDigest", OBJ_nid2ln(mdnid), -1);
	LAPPEND_STR(interp, certPtr, "publicKeyAlgorithm", OBJ_nid2ln(pknid), -1);
	LAPPEND_INT(interp, certPtr, "bits", bits); /* Effective security bits */

	key = X509_get0_pubkey_bitstr(cert);
	len = String_to_Hex(key->data, key->length, buffer, BUFSIZ);
	LAPPEND_STR(interp, certPtr, "publicKey", buffer, len);

	len = 0;
	if (X509_pubkey_digest(cert, EVP_get_digestbynid(pknid), md, &n)) {
	    len = String_to_Hex(md, (int)n, buffer, BUFSIZ);
	}
	LAPPEND_STR(interp, certPtr, "publicKeyHash", buffer, len);

	/* digest of the DER representation of the certificate */
	len = 0;
	if (X509_digest(cert, EVP_get_digestbynid(mdnid), md, &n)) {
	    len = String_to_Hex(md, (int)n, buffer, BUFSIZ);
	}
	LAPPEND_STR(interp, certPtr, "signatureHash", buffer, len);
    }

    /* Certificate Purpose. Call before checking for extensions. */
    LAPPEND_STR(interp, certPtr, "purpose", Tls_x509Purpose(cert), -1);
    LAPPEND_OBJ(interp, certPtr, "certificatePurpose", Tls_x509Purposes(interp, cert));

    /* Get extensions flags */

	and/or issuer names over time. RFC 5280 section 4.1.2.8 */
    {
	const ASN1_BIT_STRING *iuid, *suid;
        X509_get0_uids(cert, &iuid, &suid);

	Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("issuerUniqueId", -1));
	if (iuid != NULL) {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewByteArrayObj((char *)iuid->data, iuid->length));
	} else {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("", -1));
	}

	Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("subjectUniqueId", -1));
	if (suid != NULL) {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewByteArrayObj((char *)suid->data, suid->length));
	} else {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("", -1));
	}
    }

    /* X509 v3 Extensions - RFC 5280 section 4.1.2.9 */
    LAPPEND_INT(interp, certPtr, "extCount", X509_get_ext_count(cert));

    /* Subject Information Access - RFC 5280 section 4.2.2.2, NID_sinfo_access */

    /* Certificate Alias. If uses a PKCS#12 structure, alias will reflect the
	friendlyName attribute (RFC 2985). */
    {
	len = 0;
        char *string = X509_alias_get0(cert, &len);
	LAPPEND_STR(interp, certPtr, "alias", string, len);
    }

    /* Certificate and dump all data */
    {
	char certStr[CERT_STR_SIZE];

	/* Get certificate */
	len = BIO_to_Buffer(PEM_write_bio_X509(bio, cert), bio, certStr, CERT_STR_SIZE);
	LAPPEND_STR(interp, certPtr, "certificate", certStr, len);

	/* Get all cert info */
	len = BIO_to_Buffer(X509_print_ex(bio, cert, flags, 0), bio, certStr, CERT_STR_SIZE);
	LAPPEND_STR(interp, certPtr, "all", certStr, len);
    }

    BIO_free(bio);
    return certPtr;
}