vjcomp.c revision 28679 
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 1.8 1997/06/09 03:27:43 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(struct mbuf * bp)
44{
45  int type;
46  int proto;
47  int cproto = IpcpInfo.his_compproto >> 16;
48
49  LogPrintf(LogDEBUG, "SendPppFrame: proto = %x\n", IpcpInfo.his_compproto);
50  if (((struct ip *) MBUF_CTOP(bp))->ip_p == IPPROTO_TCP
51      && cproto == PROTO_VJCOMP) {
52    type = sl_compress_tcp(bp, (struct ip *) MBUF_CTOP(bp), &cslc, IpcpInfo.his_compproto & 0xff);
53
54    LogPrintf(LogDEBUG, "SendPppFrame: type = %x\n", type);
55    switch (type) {
56    case TYPE_IP:
57      proto = PROTO_IP;
58      break;
59    case TYPE_UNCOMPRESSED_TCP:
60      proto = PROTO_VJUNCOMP;
61      break;
62    case TYPE_COMPRESSED_TCP:
63      proto = PROTO_VJCOMP;
64      break;
65    default:
66      LogPrintf(LogERROR, "Unknown frame type %x\n", type);
67      pfree(bp);
68      return;
69    }
70  } else
71    proto = PROTO_IP;
72  HdlcOutput(PRI_NORMAL, proto, bp);
73}
74
75static struct mbuf *
76VjUncompressTcp(struct mbuf * bp, u_char type)
77{
78  u_char *bufp;
79  int len, olen, rlen;
80  struct mbuf *nbp;
81  u_char work[MAX_HDR + MAX_VJHEADER];	/* enough to hold TCP/IP header */
82
83  olen = len = plength(bp);
84  if (type == TYPE_UNCOMPRESSED_TCP) {
85
86    /*
87     * Uncompressed packet does NOT change its size, so that we can use mbuf
88     * space for uncompression job.
89     */
90    bufp = MBUF_CTOP(bp);
91    len = sl_uncompress_tcp(&bufp, len, type, &cslc);
92    if (len <= 0) {
93      pfree(bp);
94      bp = NULLBUFF;
95    }
96    return (bp);
97  }
98
99  /*
100   * Handle compressed packet. 1) Read upto MAX_VJHEADER bytes into work
101   * space. 2) Try to uncompress it. 3) Compute amount of necesary space. 4)
102   * Copy unread data info there.
103   */
104  if (len > MAX_VJHEADER)
105    len = MAX_VJHEADER;
106  rlen = len;
107  bufp = work + MAX_HDR;
108  bp = mbread(bp, bufp, rlen);
109  len = sl_uncompress_tcp(&bufp, olen, type, &cslc);
110  if (len <= 0) {
111    pfree(bp);
112    return NULLBUFF;
113  }
114  len -= olen;
115  len += rlen;
116  nbp = mballoc(len, MB_VJCOMP);
117  bcopy(bufp, MBUF_CTOP(nbp), len);
118  nbp->next = bp;
119  return (nbp);
120}
121
122struct mbuf *
123VjCompInput(struct mbuf * bp, int proto)
124{
125  u_char type;
126
127  LogPrintf(LogDEBUG, "VjCompInput: proto %02x\n", proto);
128  LogDumpBp(LogDEBUG, "Raw packet info:", bp);
129
130  switch (proto) {
131  case PROTO_VJCOMP:
132    type = TYPE_COMPRESSED_TCP;
133    break;
134  case PROTO_VJUNCOMP:
135    type = TYPE_UNCOMPRESSED_TCP;
136    break;
137  default:
138    LogPrintf(LogERROR, "VjCompInput...???\n");
139    return (bp);
140  }
141  bp = VjUncompressTcp(bp, type);
142  return (bp);
143}
144