xdr_rec.c

linux下用PCMCIA无线网卡虚拟无线AP的程序源码

/* @(#)xdr_rec.c	2.2 88/08/01 4.0 RPCSRC */
/*
 * 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
 */
#define __FORCE_GLIBC__
#include <features.h>

/*
 * 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(u_long).  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 <stdio.h>
#include <string.h>
#include <rpc/types.h>
#include <rpc/xdr.h>
#include <netinet/in.h>

extern long lseek();

static u_int fix_buf_size();

static bool_t xdrrec_getlong();
static bool_t xdrrec_putlong();
static bool_t xdrrec_getbytes();
static bool_t xdrrec_putbytes();
static u_int xdrrec_getpos();
static bool_t xdrrec_setpos();
static int32_t *xdrrec_inline();
static void xdrrec_destroy();

static struct xdr_ops xdrrec_ops = {
	xdrrec_getlong,
	xdrrec_putlong,
	xdrrec_getbytes,
	xdrrec_putbytes,
	xdrrec_getpos,
	xdrrec_setpos,
	xdrrec_inline,
	xdrrec_destroy
};

/*
 * 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 a long 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 ((u_long)(1 << 31))

typedef struct rec_strm {
	caddr_t tcp_handle;
	caddr_t the_buffer;
	/*
	 * out-goung bits
	 */
	int (*writeit) ();
	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 */
	u_long *frag_header;		/* beginning of curren fragment */
	bool_t frag_sent;			/* true if buffer sent in middle of record */
	/*
	 * in-coming bits
	 */
	int (*readit) ();
	u_long 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 */
	long fbtbc;					/* fragment bytes to be consumed */
	bool_t last_frag;
	u_int sendsize;
	u_int recvsize;
} RECSTREAM;

static bool_t flush_out(register RECSTREAM *rstrm, bool_t eor);
static bool_t set_input_fragment(register RECSTREAM *rstrm);
static bool_t get_input_bytes(register RECSTREAM *rstrm,
							  register caddr_t addr, register int len);
static bool_t skip_input_bytes(register RECSTREAM *rstrm, long cnt);

/*
 * 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.
 */
void xdrrec_create(xdrs, sendsize, recvsize, tcp_handle, readit, writeit)
register XDR *xdrs;
register u_int sendsize;
register u_int recvsize;
caddr_t tcp_handle;
int (*readit) ();				/* like read, but pass it a tcp_handle, not sock */
int (*writeit) ();				/* like write, but pass it a tcp_handle, not sock */
{
	register RECSTREAM *rstrm = (RECSTREAM *) mem_alloc(sizeof(RECSTREAM));

	if (rstrm == NULL) {
		(void) fprintf(stderr, "xdrrec_create: out of memory\n");
		/* 
		 *  This is bad.  Should rework xdrrec_create to 
		 *  return a handle, and in this case return NULL
		 */
		return;
	}
	/*
	 * adjust sizes and allocate buffer quad byte aligned
	 */
	rstrm->sendsize = sendsize = fix_buf_size(sendsize);
	rstrm->recvsize = recvsize = fix_buf_size(recvsize);
	rstrm->the_buffer =
		mem_alloc(sendsize + recvsize + BYTES_PER_XDR_UNIT);
	if (rstrm->the_buffer == NULL) {
		(void) fprintf(stderr, "xdrrec_create: out of memory\n");
		return;
	}
	for (rstrm->out_base = rstrm->the_buffer;
		 (u_int) rstrm->out_base % BYTES_PER_XDR_UNIT != 0;
		 rstrm->out_base++);
	rstrm->in_base = rstrm->out_base + sendsize;
	/*
	 * now the rest ...
	 */
	xdrs->x_ops = &xdrrec_ops;
	xdrs->x_private = (caddr_t) rstrm;
	rstrm->tcp_handle = tcp_handle;
	rstrm->readit = readit;
	rstrm->writeit = writeit;
	rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
	rstrm->frag_header = (u_long *) rstrm->out_base;
	rstrm->out_finger += sizeof(u_long);
	rstrm->out_boundry += sendsize;
	rstrm->frag_sent = FALSE;
	rstrm->in_size = recvsize;
	rstrm->in_boundry = rstrm->in_base;
	rstrm->in_finger = (rstrm->in_boundry += recvsize);
	rstrm->fbtbc = 0;
	rstrm->last_frag = TRUE;
}


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

static bool_t xdrrec_getlong(xdrs, lp)
XDR *xdrs;
long *lp;
{
	register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
	register long *buflp = (long *) (rstrm->in_finger);
	long mylong;

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

		*lp = (long) ntohl((u_long) mylong);
	}
	return (TRUE);
}

static bool_t xdrrec_putlong(xdrs, lp)
XDR *xdrs;
long *lp;
{
	register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
	register long *dest_lp = ((long *) (rstrm->out_finger));

	if ((rstrm->out_finger += sizeof(long)) > rstrm->out_boundry) {
		/*
		 * this case should almost never happen so the code is
		 * inefficient
		 */
		rstrm->out_finger -= sizeof(long);

		rstrm->frag_sent = TRUE;
		if (!flush_out(rstrm, FALSE))
			return (FALSE);
		dest_lp = ((long *) (rstrm->out_finger));
		rstrm->out_finger += sizeof(long);
	}
	*dest_lp = (long) htonl((u_long) (*lp));
	return (TRUE);
}

static bool_t
/* must manage buffers, fragments, and records */
xdrrec_getbytes(xdrs, addr, len)
XDR *xdrs;
register caddr_t addr;
register u_int len;
{
	register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
	register 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(xdrs, addr, len)
XDR *xdrs;
register caddr_t addr;
register u_int len;
{
	register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
	register int current;

	while (len > 0) {
		current = (u_int) rstrm->out_boundry - (u_int) rstrm->out_finger;
		current = (len < current) ? len : current;
		bcopy(addr, rstrm->out_finger, 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);
		}
	}