/*
 * Copyright (C) 1997-2000 Matt Newman <[email protected]>
 * Copyright (C) 2000 Ajuba Solutions
 *


 * TLS (aka SSL) Channel - can be layered on any bi-directional
 * Tcl_Channel (Note: Requires Trf Core Patch)
 *
 * 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

 */
static int
TlsCloseProc(ClientData instanceData,	/* The socket to close. */
             Tcl_Interp *interp)	/* For error reporting - unused. */
{
    State *statePtr = (State *) instanceData;

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

    if (channelTypeVersion == TLS_CHANNEL_VERSION_1) {
	/*
	 * Remove event handler to underlying channel, this could
	 * be because we are closing for real, or being "unstacked".
	 */

	int *errorCodePtr)		/* Where to store error code. */
{
    State *statePtr = (State *) instanceData;
    int bytesRead;			/* How many bytes were read? */

    *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");

       bytesRead = 0;
       goto input;
    }

    if (!SSL_is_init_finished(statePtr->ssl)) {
	bytesRead = Tls_WaitForConnect(statePtr, errorCodePtr);
	if (bytesRead <= 0) {
            dprintf("Got an error (bytesRead = %i)", bytesRead);

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

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

    if (bytesRead < 0) {
	int err = SSL_get_error(statePtr->ssl, bytesRead);

	if (err == SSL_ERROR_SSL) {
	    Tls_Error(statePtr, SSL_ERROR(statePtr->ssl, bytesRead));
	    *errorCodePtr = ECONNABORTED;
	} else if (BIO_should_retry(statePtr->bio)) {
	    dprintf("RE! ");
	    *errorCodePtr = EAGAIN;
	} else {
	    *errorCodePtr = Tcl_GetErrno();
	    if (*errorCodePtr == ECONNRESET) {
		/* Soft EOF */
		*errorCodePtr = 0;
		bytesRead = 0;
	    }
	}
    }
    input:
    dprintf("Input(%d) -> %d [%d]", bufSize, bytesRead, *errorCodePtr);
    return bytesRead;
}

/*
 *-------------------------------------------------------------------
 *
 * TlsOutputProc --

              int *errorCodePtr)	/* Where to store error code. */
{
    State *statePtr = (State *) instanceData;
    int written, err;

    *errorCodePtr = 0;

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

    if (statePtr->flags & TLS_TCL_CALLBACK) {
       /* don't process any bytes while verify callback is running */
       written = -1;
       *errorCodePtr = EAGAIN;
       goto output;
    }

    if (!SSL_is_init_finished(statePtr->ssl)) {
	written = Tls_WaitForConnect(statePtr, errorCodePtr);
	if (written <= 0) {
            dprintf("Tls_WaitForConnect returned %i (err = %i)", written, *errorCodePtr);

	    goto output;
	}
    }
    if (statePtr->flags & TLS_TCL_INIT) {
	statePtr->flags &= ~(TLS_TCL_INIT);
    }
    if (toWrite == 0) {
	dprintf("zero-write");
	BIO_flush(statePtr->bio);
	written = 0;
	goto output;
    } else {
	/*
	 * 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);
    }
    if (written <= 0) {
	switch ((err = SSL_get_error(statePtr->ssl, written))) {
	    case SSL_ERROR_NONE:
		if (written < 0) {
		    written = 0;
		}
		break;
	    case SSL_ERROR_WANT_WRITE:
		dprintf(" write W BLOCK");
		break;
	    case SSL_ERROR_WANT_READ:
		dprintf(" write R BLOCK");
		break;
	    case SSL_ERROR_WANT_X509_LOOKUP:
		dprintf(" write X BLOCK");
		break;
	    case SSL_ERROR_ZERO_RETURN:
		dprintf(" closed");
		written = 0;
		break;
	    case SSL_ERROR_SYSCALL:
		*errorCodePtr = Tcl_GetErrno();
		dprintf(" [%d] syscall errr: %d",
			written, *errorCodePtr);
		written = -1;
		break;
	    case SSL_ERROR_SSL:
		Tls_Error(statePtr, SSL_ERROR(statePtr->ssl, written));
		*errorCodePtr = ECONNABORTED;
		written = -1;
		break;
	    default:
		dprintf(" unknown err: %d", err);
		break;
	}
    }
    output:
    dprintf("Output(%d) -> %d", toWrite, written);
    return written;
}

/*
 *-------------------------------------------------------------------
 *
 * TlsGetOptionProc --

	    return TCL_OK;
	}
	/*
	 * Request for a specific option has to fail, we don't have any.
	 */
	return TCL_ERROR;
    } else {
#if 0
	size_t len = 0;

	if (optionName != (char *) NULL) {
	    len = strlen(optionName);
	}

	if ((len == 0) || ((len > 1) && (optionName[1] == 'c') &&
		(strncmp(optionName, "-cipher", len) == 0))) {
	    if (len == 0) {
		Tcl_DStringAppendElement(dsPtr, "-cipher");
	    }
	    Tcl_DStringAppendElement(dsPtr, SSL_get_cipher(statePtr->ssl));
	    if (len) {

TlsWatchProc(ClientData instanceData,	/* The socket state. */
             int mask)			/* Events of interest; an OR-ed
                                         * combination of TCL_READABLE,
                                         * TCL_WRITABLE and TCL_EXCEPTION. */
{
    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) { return; }

    if (channelTypeVersion == TLS_CHANNEL_VERSION_2) {
	Tcl_Channel     downChan;

    if (statePtr->flags & TLS_TCL_CALLBACK) {
	return 0;
    }

    if (statePtr->flags & TLS_TCL_INIT
	    && !SSL_is_init_finished(statePtr->ssl)) {
	int errorCode = 0;
	if (Tls_WaitForConnect(statePtr, &errorCode) <= 0 && errorCode == EAGAIN) {
            dprintf("Async flag could be set (didn't check) and errorCode == EAGAIN");
	    return 0;
	}
    }

    return mask;
}


static void
TlsChannelHandler (clientData, mask)
    ClientData     clientData;
    int            mask;
{
    State *statePtr = (State *) clientData;

    dprintf("HANDLER(0x%x)", mask);
    Tcl_Preserve( (ClientData)statePtr);

    if (mask & TCL_READABLE) {
	BIO_set_flags(statePtr->p_bio, BIO_FLAGS_READ);
    } else {
	BIO_clear_flags(statePtr->p_bio, BIO_FLAGS_READ);
    }

int
Tls_WaitForConnect( statePtr, errorCodePtr)
    State *statePtr;
    int *errorCodePtr;		/* Where to store error code. */
{
    int err;

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

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

    for (;;) {
	/* Not initialized yet! */
	if (statePtr->flags & TLS_TCL_SERVER) {
            dprintf("Calling SSL_accept()");
	    err = SSL_accept(statePtr->ssl);
	} else {
            dprintf("Calling SSL_connect()");
	    err = SSL_connect(statePtr->ssl);
	}

	/*SSL_write(statePtr->ssl, (char*)&err, 0);	HACK!!! */
	if (err > 0) {
            dprintf("That seems to have gone okay");
	    BIO_flush(statePtr->bio);
	} else {
	    int rc = SSL_get_error(statePtr->ssl, err);


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

	    if (rc == SSL_ERROR_SSL) {
		Tls_Error(statePtr,
			(char *)ERR_reason_error_string(ERR_get_error()));
                statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
		*errorCodePtr = ECONNABORTED;
		return -1;
	    } else if (BIO_should_retry(statePtr->bio)) {
		if (statePtr->flags & TLS_TCL_ASYNC) {
		    dprintf("E! ");
		    *errorCodePtr = EAGAIN;
		    return -1;
		} else {
		    continue;
		}
	    } else if (err == 0) {
                if (SSL_in_init(statePtr->ssl)) {
                    dprintf("SSL_in_init() is true");
                }

                if (Tcl_Eof(statePtr->self)) {
                    dprintf("Error = 0 and EOF is set, returning with 0");

                    return 0;
                }
		dprintf("CR! ");
		*errorCodePtr = ECONNRESET;
		return -1;
	    }
	    if (statePtr->flags & TLS_TCL_SERVER) {
		err = SSL_get_verify_result(statePtr->ssl);
		if (err != X509_V_OK) {
		    Tls_Error(statePtr,
			    (char *)X509_verify_cert_error_string(err));
                    statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
		    *errorCodePtr = ECONNABORTED;
		    return -1;
		}
	    }
	    *errorCodePtr = Tcl_GetErrno();
	    dprintf("ERR(%d, %d) ", rc, *errorCodePtr);
	    return -1;
	}
	dprintf("R0! ");
	return 1;
    }
}

Tcl_Channel
Tls_GetParent( statePtr )
    State *statePtr;