/*
 * Provides Custom BIO layer to interface OpenSSL with TCL. These
 * functions directly interface between the IO channel and BIO buffers.
 *
 * Copyright (C) 1997-2000 Matt Newman <[email protected]>
 * Copyright (C) 2024 Brian O'Hagan
 *

 */

#include "tlsInt.h"
#include <openssl/bio.h>

/* Define BIO methods structure */
static BIO_METHOD *BioMethods = NULL;


/*
 *-----------------------------------------------------------------------------
 *
 * BioWrite --
 *
 *	This function is used to read encrypted data from the BIO and write it
 *	into the socket. This function will be called in response to the
 *	application calling BIO_write_ex() or BIO_write().
 *
 * Results:
 *	Returns the number of bytes written to channel, 0 for EOF, or
 *	-1 for error.
 *
 * Side effects:
 *	Writes BIO data to channel.
 *
 *-----------------------------------------------------------------------------
 */

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

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

	    BIO_set_retry_read(bio);
	}
    }
    return (int) ret;
}

/*
 *-----------------------------------------------------------------------------
 *
 * BioRead --
 *
 *	This function is used to read encrypted data from the socket
 *	and write it into the BIO. This function will be called in response to
 *	the application calling BIO_read_ex() or BIO_read().
 *
 * Results:
 *	Returns the number of bytes read from channel, 0 for EOF, or -1 for
 *	error.
 *
 * Side effects:
 *	Reads channel data into BIO.
 *
 *-----------------------------------------------------------------------------
 */

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

    return (int) ret;
}

/*
 *-----------------------------------------------------------------------------
 *
 * BioPuts --
 *
 *	This function is used to read a NULL terminated string from the BIO and
 *	write it to the channel. This function will be called in response to
 *	the application calling BIO_puts().
 *
 * Results:
 *	Returns the number of bytes written to channel or 0 for error.
 *
 * Side effects:
 *	Writes data to channel.
 *
 *-----------------------------------------------------------------------------
 */

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

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

/*
 *-----------------------------------------------------------------------------
 *
 * BioCtrl --
 *
 *	This function is used to process control messages in the BIO. This
 *	function will be called in response to the application calling BIO_ctrl().
 *
 * Results:
 *	Function dependent
 *
 * Side effects:
 *	Function dependent
 *
 *-----------------------------------------------------------------------------
 */

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)", (void *) bio, cmd, num, ptr);

		dprintf("Got unknown control command (%i)", cmd);
		ret = 0;
		break;
    }
    return ret;
}

/*
 *-----------------------------------------------------------------------------
 *
 * BioNew --
 *
 *	This function is used to create a new instance of the BIO. This
 *	function will be called in response to the application calling BIO_new().
 *
 * Results:
 *	Returns boolean success result (1=success, 0=failure)
 *
 * Side effects:
 *	Initializes BIO structure.
 *
 *-----------------------------------------------------------------------------
 */

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;
}

/*
 *-----------------------------------------------------------------------------
 *
 * BioFree --
 *
 *	This function is used to destroy an instance of a BIO. This function
 *	will be called in response to the application calling BIO_free().
 *
 * Results:
 *	Returns boolean success result
 *
 * Side effects:
 *	Initializes BIO structure.
 *
 *-----------------------------------------------------------------------------
 */

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;
}

/*
 *-----------------------------------------------------------------------------
 *
 * BIO_new_tcl --
 *
 *	This function is used to initialize the BIO method handlers.
 *
 * Results:
 *	Returns pointer to BIO or NULL for failure
 *
 * Side effects:
 *	Initializes BIO Methods.
 *
 *-----------------------------------------------------------------------------
 */

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

#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;

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

/*
 *-----------------------------------------------------------------------------
 *
 * BIO_cleanup --
 *
 *	This function is used to destroy a BIO_METHOD structure and free up any
 *	memory associated with it.
 *
 * Results:
 *	Standard TCL result
 *
 * Side effects:
 *	Destroys BIO Methods.
 *
 *-----------------------------------------------------------------------------
 */

int BIO_cleanup () {
    dprintf("BIO_cleanup() called");

    if (BioMethods != NULL) {
	BIO_meth_free(BioMethods);
	BioMethods = NULL;
    }
    return TCL_OK;
}