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/*
* Input/Output VJ Compressed packets
*
* Written by Toshiharu OHNO (tony-o@iij.ad.jp)
*
* Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the Internet Initiative Japan, Inc. The name of the
* IIJ may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $Id: vjcomp.c,v 1.3 1995/05/30 03:51:02 rgrimes Exp $
*
* TODO:
*/
#include "fsm.h"
#include "lcpproto.h"
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include "slcompress.h"
#include "hdlc.h"
#include "ipcp.h"
#define MAX_VJHEADER 16 /* Maximum size of compressed header */
struct slcompress cslc;
void
VjInit()
{
sl_compress_init(&cslc);
}
void
SendPppFrame(bp)
struct mbuf *bp;
{
int type;
int proto;
int cproto = IpcpInfo.his_compproto >> 16;
#ifdef DEBUG
logprintf("SendPppFrame: proto = %x\n", IpcpInfo.his_compproto);
#endif
if (cproto== PROTO_VJCOMP) {
type = sl_compress_tcp(bp, (struct ip *)MBUF_CTOP(bp), &cslc, IpcpInfo.his_compproto & 0xff);
#ifdef DEBUG
logprintf("type = %x\n", type);
#endif
switch (type) {
case TYPE_IP:
proto = PROTO_IP;
break;
case TYPE_UNCOMPRESSED_TCP:
proto = PROTO_VJUNCOMP;
break;
case TYPE_COMPRESSED_TCP:
proto = PROTO_VJCOMP;
break;
default:
logprintf("unknown type %x\n", type);
pfree(bp);
return;
}
} else
proto = PROTO_IP;
HdlcOutput(PRI_NORMAL, proto, bp);
}
static struct mbuf *
VjUncompressTcp(bp, type)
struct mbuf *bp;
u_char type;
{
u_char *bufp;
int len, olen, rlen;
struct mbuf *nbp;
u_char work[MAX_HDR+MAX_VJHEADER]; /* enough to hold TCP/IP header */
olen = len = plength(bp);
if (type == TYPE_UNCOMPRESSED_TCP) {
/*
* Uncompressed packet does NOT change its size, so that we can
* use mbuf space for uncompression job.
*/
bufp = MBUF_CTOP(bp);
len = sl_uncompress_tcp(&bufp, len, type, &cslc);
if (len <= 0) {
pfree(bp);
bp = NULLBUFF;
}
return(bp);
}
/*
* Handle compressed packet.
* 1) Read upto MAX_VJHEADER bytes into work space.
* 2) Try to uncompress it.
* 3) Compute amount of necesary space.
* 4) Copy unread data info there.
*/
if (len > MAX_VJHEADER) len = MAX_VJHEADER;
rlen = len;
bufp = work + MAX_HDR;
bp = mbread(bp, bufp, rlen);
len = sl_uncompress_tcp(&bufp, olen, type, &cslc);
if (len <= 0) {
pfree(bp);
return NULLBUFF;
}
len -= olen;
len += rlen;
nbp = mballoc(len, MB_VJCOMP);
bcopy(bufp, MBUF_CTOP(nbp), len);
nbp->next = bp;
return(nbp);
}
struct mbuf *
VjCompInput(bp, proto)
struct mbuf *bp;
int proto;
{
u_char type;
#ifdef DEBUG
logprintf("VjCompInput (%02x):\n", proto);
DumpBp(bp);
#endif
switch (proto) {
case PROTO_VJCOMP:
type = TYPE_COMPRESSED_TCP;
break;
case PROTO_VJUNCOMP:
type = TYPE_UNCOMPRESSED_TCP;
break;
default:
logprintf("???\n");
return(bp);
}
bp = VjUncompressTcp(bp, type);
return(bp);
}
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