/*  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
 * unrestricted use provided that this legend is included on all tape
 * media and as a part of the software program in whole or part.  Users
 * may copy or modify Sun RPC without charge, but are not authorized
 * to license or distribute it to anyone else except as part of a product or
 * program developed by the user.
 * 
 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
 * 
 * Sun RPC is provided with no support and without any obligation on the
 * part of Sun Microsystems, Inc. to assist in its use, correction,
 * modification or enhancement.
 * 
 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
 * OR ANY PART THEREOF.
 * 
 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
 * or profits or other special, indirect and consequential damages, even if
 * Sun has been advised of the possibility of such damages.
 * 
 * Sun Microsystems, Inc.
 * 2550 Garcia Avenue
 * Mountain View, California  94043
 */
#ifndef	NeXT

/*  * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
 * layer above tcp (for rpc's use).
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * These routines interface XDRSTREAMS to a tcp/ip connection.
 * There is a record marking layer between the xdr stream
 * and the tcp transport level.  A record is composed on one or more
 * record fragments.  A record fragment is a thirty-two bit header followed
 * by n bytes of data, where n is contained in the header.  The header
 * is represented as a htonl(afs_uint32).  Thegh order bit encodes
 * whether or not the fragment is the last fragment of the record
 * (1 => fragment is last, 0 => more fragments to follow. 
 * The other 31 bits encode the byte length of the fragment.
 */

#include <afsconfig.h>
#include <afs/param.h>

RCSID
    ("$Header: /cvs/openafs/src/rx/xdr_rec.c,v 1.11 2009/01/28 22:33:17 shadow Exp $");

#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include "xdr.h"
#ifndef AFS_NT40_ENV
#include <sys/time.h>
#include <netinet/in.h>
#endif

#include <string.h>


/*  * A record is composed of one or more record fragments.
 * A record fragment is a two-byte header followed by zero to
 * 2**32-1 bytes.  The header is treated as an afs_int32 unsigned and is
 * encode/decoded to the network via htonl/ntohl.  The low order 31 bits
 * are a byte count of the fragment.  The highest order bit is a boolean:
 * 1 => this fragment is the last fragment of the record,
 * 0 => this fragment is followed by more fragment(s).
 *
 * The fragment/record machinery is not general;  it is constructed to
 * meet the needs of xdr and rpc based on tcp.
 */

#define LAST_FRAG ((afs_uint32)(1 << 31))

typedef struct rec_strm {
    caddr_t tcp_handle;
    /*       * out-goung bits
     */
    int (*writeit) (caddr_t tcp_handle, caddr_t out_base, int len);
    caddr_t out_base;		/* output buffer (points to frag header) */
    caddr_t out_finger;		/* next output position */
    caddr_t out_boundry;	/* data cannot up to this address */
    afs_uint32 *frag_header;	/* beginning of curren fragment */
    bool_t frag_sent;		/* true if buffer sent in middle of record */
    /*       * in-coming bits
     */
    int (*readit) (caddr_t tcp_handle, caddr_t out_base, int len);
    afs_uint32 in_size;		/* fixed size of the input buffer */
    caddr_t in_base;
    caddr_t in_finger;		/* location of next byte to be had */
    caddr_t in_boundry;		/* can read up to this location */
    afs_int32 fbtbc;		/* fragment bytes to be consumed */
    bool_t last_frag;
    u_int sendsize;
    u_int recvsize;
} RECSTREAM;

/* Prototypes for static routines */
static bool_t xdrrec_getint32(XDR * xdrs, afs_int32 * lp);
static bool_t xdrrec_putint32(XDR * xdrs, afs_int32 * lp);
static bool_t xdrrec_getbytes(XDR * xdrs, caddr_t addr,
			      u_int len);
static bool_t xdrrec_putbytes(XDR * xdrs, caddr_t addr,
			      u_int len);
static u_int xdrrec_getpos(XDR * xdrs);
static bool_t xdrrec_setpos(XDR * xdrs, u_int pos);
static afs_int32 *xdrrec_inline(XDR * xdrs, u_int len);
static void xdrrec_destroy(XDR * xdrs);
static bool_t flush_out(RECSTREAM * rstrm, bool_t eor);
static bool_t fill_input_buf(RECSTREAM * rstrm);
static bool_t get_input_bytes(RECSTREAM * rstrm,
			      caddr_t addr, int len);
static bool_t set_input_fragment(RECSTREAM * rstrm);
static bool_t skip_input_bytes(RECSTREAM * rstrm, int cnt);
static u_int fix_buf_size(u_int s);

static struct xdr_ops xdrrec_ops = {
    xdrrec_getint32,
    xdrrec_putint32,
    xdrrec_getbytes,
    xdrrec_putbytes,
    xdrrec_getpos,
    xdrrec_setpos,
    xdrrec_inline,
    xdrrec_destroy
};

/*  * Create an xdr handle for xdrrec
 * xdrrec_create fills in xdrs.  Sendsize and recvsize are
 * send and recv buffer sizes (0 => use default).
 * tcp_handle is an opaque handle that is passed as the first parameter to
 * the procedures readit and writeit.  Readit and writeit are read and
 * write respectively.   They are like the system
 * calls expect that they take an opaque handle rather than an fd.
 */
/*
	int (*readit)();  * like read, but pass it a tcp_handle, not sock *
	int (*writeit)();  * like write, but pass it a tcp_handle, not sock *
*/
void
xdrrec_create(XDR * xdrs, u_int sendsize, u_int recvsize,
	      caddr_t tcp_handle, int (*readit) (caddr_t tcp_handle,
						 caddr_t out_base, int len),
	      int (*writeit) (caddr_t tcp_handle, caddr_t out_base, int len))
{
    RECSTREAM *rstrm = (RECSTREAM *) osi_alloc(sizeof(RECSTREAM));

    if (rstrm == NULL) {
	/* 
	 *  This is bad.  Should rework xdrrec_create to 
	 *  return a handle, and in this case return NULL
	 */
	return;
    }
    xdrs->x_ops = &xdrrec_ops;
    xdrs->x_private = (caddr_t) rstrm;
    rstrm->tcp_handle = tcp_handle;
    rstrm->readit = readit;
    rstrm->writeit = writeit;
    sendsize = fix_buf_size(sendsize);
    if ((rstrm->out_base = rstrm->out_finger = rstrm->out_boundry =
	 osi_alloc(sendsize)) == NULL) {
	return;
    }
    rstrm->frag_header = (afs_uint32 *) rstrm->out_base;
    rstrm->out_finger += sizeof(afs_uint32);
    rstrm->out_boundry += sendsize;
    rstrm->frag_sent = FALSE;
    rstrm->in_size = recvsize = fix_buf_size(recvsize);
    if ((rstrm->in_base = rstrm->in_boundry = osi_alloc(recvsize)) == NULL) {
	return;
    }
    rstrm->in_finger = (rstrm->in_boundry += recvsize);
    rstrm->fbtbc = 0;
    rstrm->last_frag = TRUE;
    rstrm->sendsize = sendsize;
    rstrm->recvsize = recvsize;
}


/*  * The reoutines defined below are the xdr ops which will go into the
 * xdr handle filled in by xdrrec_create.
 */

static bool_t
xdrrec_getint32(XDR * xdrs, afs_int32 * lp)
{
    RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
    afs_int32 *buflp = (afs_int32 *) (rstrm->in_finger);
    afs_int32 myint32;

    /* first try the inline, fast case */
    if ((rstrm->fbtbc >= sizeof(afs_int32))
	&& (((int)((char *)rstrm->in_boundry - (char *)buflp)) >= sizeof(afs_int32))) {
	*lp = ntohl(*buflp);
	rstrm->fbtbc -= sizeof(afs_int32);
	rstrm->in_finger += sizeof(afs_int32);
    } else {
	if (!xdrrec_getbytes(xdrs, (caddr_t) & myint32, sizeof(afs_int32)))
	    return (FALSE);
	*lp = ntohl(myint32);
    }
    return (TRUE);
}

static bool_t
xdrrec_putint32(XDR * xdrs, afs_int32 * lp)
{
    RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
    afs_int32 *dest_lp = ((afs_int32 *) (rstrm->out_finger));

    if ((rstrm->out_finger += sizeof(afs_int32)) > rstrm->out_boundry) {
	/*
	 * this case should almost never happen so the code is
	 * inefficient
	 */
	rstrm->out_finger -= sizeof(afs_int32);
	rstrm->frag_sent = TRUE;
	if (!flush_out(rstrm, FALSE))
	    return (FALSE);
	dest_lp = ((afs_int32 *) (rstrm->out_finger));
	rstrm->out_finger += sizeof(afs_int32);
    }
    *dest_lp = htonl(*lp);
    return (TRUE);
}

static bool_t
xdrrec_getbytes(XDR * xdrs, caddr_t addr, u_int len)
{
    RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
    int current;

    while (len > 0) {
	current = rstrm->fbtbc;
	if (current == 0) {
	    if (rstrm->last_frag)
		return (FALSE);
	    if (!set_input_fragment(rstrm))
		return (FALSE);
	    continue;
	}
	current = (len < current) ? len : current;
	if (!get_input_bytes(rstrm, addr, current))
	    return (FALSE);
	addr += current;
	rstrm->fbtbc -= current;
	len -= current;
    }
    return (TRUE);
}

static bool_t
xdrrec_putbytes(XDR * xdrs, caddr_t addr, u_int len)
{
    RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
    int current;

    while (len > 0) {
	current = (u_int) (rstrm->out_boundry - rstrm->out_finger);
	current = (len < current) ? len : current;
	memcpy(rstrm->out_finger, addr, current);
	rstrm->out_finger += current;
	addr += current;
	len -= current;
	if (rstrm->out_finger == rstrm->out_boundry) {
	    rstrm->frag_sent = TRUE;
	    if (!flush_out(rstrm, FALSE))
		return (FALSE);
	}
    }
    return (TRUE);
}

static u_int
xdrrec_getpos(XDR * xdrs)
{
    RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
    u_int pos;

    pos = (u_int) lseek((int)rstrm->tcp_handle, 0, 1);
    if ((int)pos != -1)
	switch (xdrs->x_op) {

	case XDR_ENCODE:
	    pos += (u_int)(rstrm->out_finger - rstrm->out_base);
	    break;

	case XDR_DECODE:
	    pos -= (u_int)(rstrm->in_boundry - rstrm->in_finger);
	    break;

	default:
	    pos = (u_int) - 1;
	    break;
	}
    return (pos);
}

static bool_t
xdrrec_setpos(XDR * xdrs, u_int pos)
{
    RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
    u_int currpos = xdrrec_getpos(xdrs);
    int delta = currpos - pos;
    caddr_t newpos;

    if ((int)currpos != -1)
	switch (xdrs->x_op) {

	case XDR_ENCODE:
	    newpos = rstrm->out_finger - delta;
	    if ((newpos > (caddr_t) (rstrm->frag_header))
		&& (newpos < rstrm->out_boundry)) {
		rstrm->out_finger = newpos;
		return (TRUE);
	    }
	    break;

	case XDR_DECODE:
	    newpos = rstrm->in_finger - delta;
	    if ((delta < (int)(rstrm->fbtbc)) && (newpos <= rstrm->in_boundry)
		&& (newpos >= rstrm->in_base)) {
		rstrm->in_finger = newpos;
		rstrm->fbtbc -= delta;
		return (TRUE);
	    }
	    break;
	}
    return (FALSE);
}

static afs_int32 *
xdrrec_inline(XDR * xdrs, u_int len)
{
    RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
    afs_int32 *buf = NULL;

    switch (xdrs->x_op) {

    case XDR_ENCODE:
	if ((rstrm->out_finger + len) <= rstrm->out_boundry) {
	    buf = (afs_int32 *) rstrm->out_finger;
	    rstrm->out_finger += len;
	}
	break;

    case XDR_DECODE:
	if ((len <= rstrm->fbtbc)
	    && ((rstrm->in_finger + len) <= rstrm->in_boundry)) {
	    buf = (afs_int32 *) rstrm->in_finger;
	    rstrm->fbtbc -= len;
	    rstrm->in_finger += len;
	}
	break;
    }
    return (buf);
}

static void
xdrrec_destroy(XDR * xdrs)
{
    RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;

    osi_free(rstrm->out_base, rstrm->sendsize);
    osi_free(rstrm->in_base, rstrm->recvsize);
    osi_free((caddr_t) rstrm, sizeof(RECSTREAM));
}


/*
 * Exported routines to manage xdr records
 */

/*
 * Before reading (deserializing from the stream, one should always call
 * this procedure to guarantee proper record alignment.
 */
bool_t
xdrrec_skiprecord(XDR * xdrs)
{
    RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);

    while (rstrm->fbtbc > 0 || (!rstrm->last_frag)) {
	if (!skip_input_bytes(rstrm, rstrm->fbtbc))
	    return (FALSE);
	rstrm->fbtbc = 0;
	if ((!rstrm->last_frag) && (!set_input_fragment(rstrm)))
	    return (FALSE);
    }
    rstrm->last_frag = FALSE;
    return (TRUE);
}

/*
 * Look ahead fuction.
 * Returns TRUE iff there is no more input in the buffer 
 * after consuming the rest of the current record.
 */
bool_t
xdrrec_eof(XDR * xdrs)
{
    RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);

    while (rstrm->fbtbc > 0 || (!rstrm->last_frag)) {
	if (!skip_input_bytes(rstrm, rstrm->fbtbc))
	    return (TRUE);
	rstrm->fbtbc = 0;
	if ((!rstrm->last_frag) && (!set_input_fragment(rstrm)))
	    return (TRUE);
    }
    if (rstrm->in_finger == rstrm->in_boundry)
	return (TRUE);
    return (FALSE);
}

/*
 * The client must tell the package when an end-of-record has occurred.
 * The second paraemters tells whether the record should be flushed to the
 * (output) tcp stream.  (This let's the package support batched or
 * pipelined procedure calls.)  TRUE => immmediate flush to tcp connection.
 */
bool_t
xdrrec_endofrecord(XDR * xdrs, bool_t sendnow)
{
    RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
    afs_uint32 len;	/* fragment length */

    if (sendnow || rstrm->frag_sent
	|| ((afs_uint32) (rstrm->out_finger + sizeof(afs_uint32)) >=
	    (afs_uint32) rstrm->out_boundry)) {
	rstrm->frag_sent = FALSE;
	return (flush_out(rstrm, TRUE));
    }
    len =
	(afs_uint32) (rstrm->out_finger - (caddr_t)rstrm->frag_header) -
	sizeof(afs_uint32);
    *(rstrm->frag_header) = htonl(len | LAST_FRAG);
    rstrm->frag_header = (afs_uint32 *) rstrm->out_finger;
    rstrm->out_finger += sizeof(afs_uint32);
    return (TRUE);
}


/*
 * Internal useful routines
 */
static bool_t
flush_out(RECSTREAM * rstrm, bool_t eor)
{
    afs_uint32 eormask = (eor == TRUE) ? LAST_FRAG : 0;
    afs_uint32 len =
	(afs_uint32) (rstrm->out_finger - (caddr_t)rstrm->frag_header) -
	sizeof(afs_uint32);

    *(rstrm->frag_header) = htonl(len | eormask);
    len = (afs_uint32) (rstrm->out_finger) - (afs_uint32) (rstrm->out_base);
    if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int)len)
	!= (int)len)
	return (FALSE);
    rstrm->frag_header = (afs_uint32 *) rstrm->out_base;
    rstrm->out_finger = (caddr_t) rstrm->out_base + sizeof(afs_uint32);
    return (TRUE);
}

static bool_t
fill_input_buf(RECSTREAM * rstrm)
{
    caddr_t where = rstrm->in_base;
    int len = rstrm->in_size;
    u_int adjust = (u_int) ((size_t)rstrm->in_boundry % BYTES_PER_XDR_UNIT);

    /* Bump the current position out to the next alignment boundary */
    where += adjust;
    len -= adjust;

    if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
	return (FALSE);
    rstrm->in_finger = where;
    where += len;
    rstrm->in_boundry = where;
    return (TRUE);
}

static bool_t
get_input_bytes(RECSTREAM * rstrm, caddr_t addr,
		int len)
{
    int current;

    while (len > 0) {
	current = (int)(rstrm->in_boundry - rstrm->in_finger);
	if (current == 0) {
	    if (!fill_input_buf(rstrm))
		return (FALSE);
	    continue;
	}
	current = (len < current) ? len : current;
	memcpy(addr, rstrm->in_finger, current);
	rstrm->in_finger += current;
	addr += current;
	len -= current;
    }
    return (TRUE);
}

/* next two bytes of the input stream are treated as a header */
static bool_t
set_input_fragment(RECSTREAM * rstrm)
{
    afs_uint32 header;

    if (!get_input_bytes(rstrm, (caddr_t) & header, sizeof(header)))
	return (FALSE);
    header = ntohl(header);
    rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
    rstrm->fbtbc = header & (~LAST_FRAG);
    return (TRUE);
}

/* consumes input bytes; knows nothing about records! */
static bool_t
skip_input_bytes(RECSTREAM * rstrm, int cnt)
{
    int current;

    while (cnt > 0) {
	current = (int)(rstrm->in_boundry - rstrm->in_finger);
	if (current == 0) {
	    if (!fill_input_buf(rstrm))
		return (FALSE);
	    continue;
	}
	current = (cnt < current) ? cnt : current;
	rstrm->in_finger += current;
	cnt -= current;
    }
    return (TRUE);
}

static u_int
fix_buf_size(u_int s)
{

    if (s < 100)
	s = 4000;
    return ((s + BYTES_PER_XDR_UNIT - 1) / BYTES_PER_XDR_UNIT)
	* BYTES_PER_XDR_UNIT;

}

#endif /* NeXT */
