1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
|
/*
* Copyright (c) 1989, 1990, 1991, 1993, 1994, 1995, 1996, 1997
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may 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
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/* \summary: Compressed Serial Line Internet Protocol printer */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <netdissect-stdinc.h>
#include "netdissect.h"
#include "extract.h"
#include "ip.h"
#include "tcp.h"
#include "slcompress.h"
/*
* definitions of the pseudo- link-level header attached to slip
* packets grabbed by the packet filter (bpf) traffic monitor.
*/
#define SLIP_HDRLEN 16
#define SLX_DIR 0
#define SLX_CHDR 1
#define CHDR_LEN 15
#define SLIPDIR_IN 0
#define SLIPDIR_OUT 1
static const char tstr[] = "[|slip]";
static u_int lastlen[2][256];
static u_int lastconn = 255;
static int sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
static int compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
u_int
sl_if_print(netdissect_options *ndo,
const struct pcap_pkthdr *h, const u_char *p)
{
register u_int caplen = h->caplen;
register u_int length = h->len;
register const struct ip *ip;
if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
ND_PRINT((ndo, "%s", tstr));
return (caplen);
}
caplen -= SLIP_HDRLEN;
length -= SLIP_HDRLEN;
ip = (const struct ip *)(p + SLIP_HDRLEN);
if (ndo->ndo_eflag)
if (sliplink_print(ndo, p, ip, length) == -1) {
ND_PRINT((ndo, "%s", tstr));
return (caplen + SLIP_HDRLEN);
}
if (caplen < 1 || length < 1) {
ND_PRINT((ndo, "%s", tstr));
return (caplen + SLIP_HDRLEN);
}
switch (IP_V(ip)) {
case 4:
ip_print(ndo, (const u_char *)ip, length);
break;
case 6:
ip6_print(ndo, (const u_char *)ip, length);
break;
default:
ND_PRINT((ndo, "ip v%d", IP_V(ip)));
}
return (SLIP_HDRLEN);
}
u_int
sl_bsdos_if_print(netdissect_options *ndo,
const struct pcap_pkthdr *h, const u_char *p)
{
register u_int caplen = h->caplen;
register u_int length = h->len;
register const struct ip *ip;
if (caplen < SLIP_HDRLEN) {
ND_PRINT((ndo, "%s", tstr));
return (caplen);
}
length -= SLIP_HDRLEN;
ip = (const struct ip *)(p + SLIP_HDRLEN);
#ifdef notdef
if (ndo->ndo_eflag)
sliplink_print(ndo, p, ip, length);
#endif
ip_print(ndo, (const u_char *)ip, length);
return (SLIP_HDRLEN);
}
static int
sliplink_print(netdissect_options *ndo,
register const u_char *p, register const struct ip *ip,
register u_int length)
{
int dir;
u_int hlen;
dir = p[SLX_DIR];
switch (dir) {
case SLIPDIR_IN:
ND_PRINT((ndo, "I "));
break;
case SLIPDIR_OUT:
ND_PRINT((ndo, "O "));
break;
default:
ND_PRINT((ndo, "Invalid direction %d ", dir));
dir = -1;
break;
}
if (ndo->ndo_nflag) {
/* XXX just dump the header */
register int i;
for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
ND_PRINT((ndo, "%02x.", p[i]));
ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
return 0;
}
switch (p[SLX_CHDR] & 0xf0) {
case TYPE_IP:
ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
break;
case TYPE_UNCOMPRESSED_TCP:
/*
* The connection id is stored in the IP protocol field.
* Get it from the link layer since sl_uncompress_tcp()
* has restored the IP header copy to IPPROTO_TCP.
*/
lastconn = ((const struct ip *)&p[SLX_CHDR])->ip_p;
ND_PRINT((ndo, "utcp %d: ", lastconn));
if (dir == -1) {
/* Direction is bogus, don't use it */
return 0;
}
ND_TCHECK(*ip);
hlen = IP_HL(ip);
ND_TCHECK(*((const struct tcphdr *)&((const int *)ip)[hlen]));
hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]);
lastlen[dir][lastconn] = length - (hlen << 2);
break;
default:
if (dir == -1) {
/* Direction is bogus, don't use it */
return 0;
}
if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
if (compressed_sl_print(ndo, &p[SLX_CHDR], ip,
length, dir) == -1)
goto trunc;
ND_PRINT((ndo, ": "));
} else
ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
}
return 0;
trunc:
return -1;
}
static const u_char *
print_sl_change(netdissect_options *ndo,
const char *str, register const u_char *cp)
{
register u_int i;
if ((i = *cp++) == 0) {
i = EXTRACT_16BITS(cp);
cp += 2;
}
ND_PRINT((ndo, " %s%d", str, i));
return (cp);
}
static const u_char *
print_sl_winchange(netdissect_options *ndo,
register const u_char *cp)
{
register short i;
if ((i = *cp++) == 0) {
i = EXTRACT_16BITS(cp);
cp += 2;
}
if (i >= 0)
ND_PRINT((ndo, " W+%d", i));
else
ND_PRINT((ndo, " W%d", i));
return (cp);
}
static int
compressed_sl_print(netdissect_options *ndo,
const u_char *chdr, const struct ip *ip,
u_int length, int dir)
{
register const u_char *cp = chdr;
register u_int flags, hlen;
flags = *cp++;
if (flags & NEW_C) {
lastconn = *cp++;
ND_PRINT((ndo, "ctcp %d", lastconn));
} else
ND_PRINT((ndo, "ctcp *"));
/* skip tcp checksum */
cp += 2;
switch (flags & SPECIALS_MASK) {
case SPECIAL_I:
ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
break;
case SPECIAL_D:
ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
break;
default:
if (flags & NEW_U)
cp = print_sl_change(ndo, "U=", cp);
if (flags & NEW_W)
cp = print_sl_winchange(ndo, cp);
if (flags & NEW_A)
cp = print_sl_change(ndo, "A+", cp);
if (flags & NEW_S)
cp = print_sl_change(ndo, "S+", cp);
break;
}
if (flags & NEW_I)
cp = print_sl_change(ndo, "I+", cp);
/*
* 'hlen' is the length of the uncompressed TCP/IP header (in words).
* 'cp - chdr' is the length of the compressed header.
* 'length - hlen' is the amount of data in the packet.
*/
ND_TCHECK(*ip);
hlen = IP_HL(ip);
ND_TCHECK(*((const struct tcphdr *)&((const int32_t *)ip)[hlen]));
hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
lastlen[dir][lastconn] = length - (hlen << 2);
ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
return 0;
trunc:
return -1;
}
|
