vjcomp.c revision 30715 
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 1.10 1997/10/07 00:56:58 brian Exp $
21 *
22 *  TODO:
23 */
24#include <sys/types.h>
25#include <netinet/in.h>
26#include <netinet/in_systm.h>
27#include <netinet/ip.h>
28
29#include <string.h>
30
31#include "mbuf.h"
32#include "log.h"
33#include "defs.h"
34#include "timer.h"
35#include "fsm.h"
36#include "lcpproto.h"
37#include "slcompress.h"
38#include "hdlc.h"
39#include "ipcp.h"
40#include "vjcomp.h"
41
42#define MAX_VJHEADER 16		/* Maximum size of compressed header */
43
44struct slcompress cslc;
45
46void
47VjInit(int max_state)
48{
49  sl_compress_init(&cslc, max_state);
50}
51
52void
53SendPppFrame(struct mbuf * bp)
54{
55  int type;
56  int proto;
57  int cproto = IpcpInfo.his_compproto >> 16;
58
59  LogPrintf(LogDEBUG, "SendPppFrame: proto = %x\n", IpcpInfo.his_compproto);
60  if (((struct ip *) MBUF_CTOP(bp))->ip_p == IPPROTO_TCP
61      && cproto == PROTO_VJCOMP) {
62    type = sl_compress_tcp(bp, (struct ip *) MBUF_CTOP(bp), &cslc, IpcpInfo.his_compproto & 0xff);
63
64    LogPrintf(LogDEBUG, "SendPppFrame: type = %x\n", type);
65    switch (type) {
66    case TYPE_IP:
67      proto = PROTO_IP;
68      break;
69    case TYPE_UNCOMPRESSED_TCP:
70      proto = PROTO_VJUNCOMP;
71      break;
72    case TYPE_COMPRESSED_TCP:
73      proto = PROTO_VJCOMP;
74      break;
75    default:
76      LogPrintf(LogERROR, "Unknown frame type %x\n", type);
77      pfree(bp);
78      return;
79    }
80  } else
81    proto = PROTO_IP;
82  HdlcOutput(PRI_NORMAL, proto, bp);
83}
84
85static struct mbuf *
86VjUncompressTcp(struct mbuf * bp, u_char type)
87{
88  u_char *bufp;
89  int len, olen, rlen;
90  struct mbuf *nbp;
91  u_char work[MAX_HDR + MAX_VJHEADER];	/* enough to hold TCP/IP header */
92
93  olen = len = plength(bp);
94  if (type == TYPE_UNCOMPRESSED_TCP) {
95
96    /*
97     * Uncompressed packet does NOT change its size, so that we can use mbuf
98     * space for uncompression job.
99     */
100    bufp = MBUF_CTOP(bp);
101    len = sl_uncompress_tcp(&bufp, len, type, &cslc);
102    if (len <= 0) {
103      pfree(bp);
104      bp = NULLBUFF;
105    }
106    return (bp);
107  }
108
109  /*
110   * Handle compressed packet. 1) Read upto MAX_VJHEADER bytes into work
111   * space. 2) Try to uncompress it. 3) Compute amount of necesary space. 4)
112   * Copy unread data info there.
113   */
114  if (len > MAX_VJHEADER)
115    len = MAX_VJHEADER;
116  rlen = len;
117  bufp = work + MAX_HDR;
118  bp = mbread(bp, bufp, rlen);
119  len = sl_uncompress_tcp(&bufp, olen, type, &cslc);
120  if (len <= 0) {
121    pfree(bp);
122    return NULLBUFF;
123  }
124  len -= olen;
125  len += rlen;
126  nbp = mballoc(len, MB_VJCOMP);
127  memcpy(MBUF_CTOP(nbp), bufp, len);
128  nbp->next = bp;
129  return (nbp);
130}
131
132struct mbuf *
133VjCompInput(struct mbuf * bp, int proto)
134{
135  u_char type;
136
137  LogPrintf(LogDEBUG, "VjCompInput: proto %02x\n", proto);
138  LogDumpBp(LogDEBUG, "Raw packet info:", bp);
139
140  switch (proto) {
141  case PROTO_VJCOMP:
142    type = TYPE_COMPRESSED_TCP;
143    break;
144  case PROTO_VJUNCOMP:
145    type = TYPE_UNCOMPRESSED_TCP;
146    break;
147  default:
148    LogPrintf(LogERROR, "VjCompInput...???\n");
149    return (bp);
150  }
151  bp = VjUncompressTcp(bp, type);
152  return (bp);
153}
154