/*
 * Copyright (C) 1997-2000 Matt Newman <matt@novadigm.com>
 *
 * 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)
#define BIO_get_shutdown(bio)            ((bio)->shutdown)
#define BIO_set_data(bio, val)           (bio)->ptr = (val)
#define BIO_set_init(bio, val)           (bio)->init = (val)
#define BIO_set_shutdown(bio, val)       (bio)->shutdown = (val)

/* XXX: This assumes the variable being assigned to is BioMethods */
#define BIO_meth_new(type_, name_)       (BIO_METHOD *)Tcl_Alloc(sizeof(BIO_METHOD)); \
                                         memset(BioMethods, 0, sizeof(BIO_METHOD)); \
                                         BioMethods->type = type_; \
                                         BioMethods->name = name_;
#define BIO_meth_set_write(bio, val)     (bio)->bwrite = val;
#define BIO_meth_set_read(bio, val)      (bio)->bread = val;
#define BIO_meth_set_puts(bio, val)      (bio)->bputs = val;
#define BIO_meth_set_ctrl(bio, val)      (bio)->ctrl = val;
#define BIO_meth_set_create(bio, val)    (bio)->create = val;
#define BIO_meth_set_destroy(bio, val)   (bio)->destroy = val;
#endif

/*
 * Forward declarations
 */

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);
}