vjcomp.c revision 26516 
1/*
2 *	       Input/Output VJ Compressed packets
3 *
4 *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
5 *
6 *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by the Internet Initiative Japan, Inc.  The name of the
14 * IIJ may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 *
20 * $Id: vjcomp.c,v 1.7 1997/05/07 23:30:50 brian Exp $
21 *
22 *  TODO:
23 */
24#include "fsm.h"
25#include "lcpproto.h"
26#include <netinet/in_systm.h>
27#include <netinet/ip.h>
28#include "slcompress.h"
29#include "hdlc.h"
30#include "ipcp.h"
31
32#define MAX_VJHEADER 16	/* Maximum size of compressed header */
33
34struct slcompress cslc;
35
36void
37VjInit()
38{
39  sl_compress_init(&cslc);
40}
41
42void
43SendPppFrame(bp)
44struct mbuf *bp;
45{
46  int type;
47  int proto;
48  int cproto = IpcpInfo.his_compproto >> 16;
49
50  LogPrintf(LogDEBUG, "SendPppFrame: proto = %x\n", IpcpInfo.his_compproto);
51  if (((struct ip *)MBUF_CTOP(bp))->ip_p == IPPROTO_TCP
52      && cproto== PROTO_VJCOMP) {
53    type = sl_compress_tcp(bp, (struct ip *)MBUF_CTOP(bp), &cslc, IpcpInfo.his_compproto & 0xff);
54
55    LogPrintf(LogDEBUG, "SendPppFrame: type = %x\n", type);
56    switch (type) {
57    case TYPE_IP:
58      proto = PROTO_IP;
59      break;
60    case TYPE_UNCOMPRESSED_TCP:
61      proto = PROTO_VJUNCOMP;
62      break;
63    case TYPE_COMPRESSED_TCP:
64      proto = PROTO_VJCOMP;
65      break;
66    default:
67      LogPrintf(LogERROR, "Unknown frame type %x\n", type);
68      pfree(bp);
69      return;
70    }
71  } else
72    proto = PROTO_IP;
73  HdlcOutput(PRI_NORMAL, proto, bp);
74}
75
76static struct mbuf *
77VjUncompressTcp(bp, type)
78struct mbuf *bp;
79u_char type;
80{
81  u_char *bufp;
82  int len, olen, rlen;
83  struct mbuf *nbp;
84  u_char work[MAX_HDR+MAX_VJHEADER];   /* enough to hold TCP/IP header */
85
86  olen = len = plength(bp);
87  if (type == TYPE_UNCOMPRESSED_TCP) {
88    /*
89     * Uncompressed packet does NOT change its size, so that we can
90     * use mbuf space for uncompression job.
91     */
92    bufp = MBUF_CTOP(bp);
93    len = sl_uncompress_tcp(&bufp, len, type, &cslc);
94    if (len <= 0) {
95      pfree(bp);
96      bp = NULLBUFF;
97    }
98    return(bp);
99  }
100  /*
101   *  Handle compressed packet.
102   *    1) Read upto MAX_VJHEADER bytes into work space.
103   *	2) Try to uncompress it.
104   *    3) Compute amount of necesary space.
105   *    4) Copy unread data info there.
106   */
107  if (len > MAX_VJHEADER) len = MAX_VJHEADER;
108  rlen = len;
109  bufp = work + MAX_HDR;
110  bp = mbread(bp, bufp, rlen);
111  len = sl_uncompress_tcp(&bufp, olen, type, &cslc);
112  if (len <= 0) {
113    pfree(bp);
114    return NULLBUFF;
115  }
116  len -= olen;
117  len += rlen;
118  nbp = mballoc(len, MB_VJCOMP);
119  bcopy(bufp, MBUF_CTOP(nbp), len);
120  nbp->next = bp;
121  return(nbp);
122}
123
124struct mbuf *
125VjCompInput(bp, proto)
126struct mbuf *bp;
127int proto;
128{
129  u_char type;
130
131  LogPrintf(LogDEBUG, "VjCompInput: proto %02x\n", proto);
132  LogDumpBp(LogDEBUG, "Raw packet info:", bp);
133
134  switch (proto) {
135  case PROTO_VJCOMP:
136    type = TYPE_COMPRESSED_TCP;
137    break;
138  case PROTO_VJUNCOMP:
139    type = TYPE_UNCOMPRESSED_TCP;
140    break;
141  default:
142    LogPrintf(LogERROR, "VjCompInput...???\n");
143    return(bp);
144  }
145  bp = VjUncompressTcp(bp, type);
146  return(bp);
147}
148