1 /*
2 * Copyright (c) 1989, 1990, 1991, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 */
21
22 #define NETDISSECT_REWORKED
23 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26
27 #include <tcpdump-stdinc.h>
28
29 #include "interface.h"
30 #include "extract.h" /* must come after interface.h */
31
32 #include "ip.h"
33 #include "tcp.h"
34 #include "slcompress.h"
35
36 /*
37 * definitions of the pseudo- link-level header attached to slip
38 * packets grabbed by the packet filter (bpf) traffic monitor.
39 */
40 #define SLIP_HDRLEN 16
41
42 #define SLX_DIR 0
43 #define SLX_CHDR 1
44 #define CHDR_LEN 15
45
46 #define SLIPDIR_IN 0
47 #define SLIPDIR_OUT 1
48
49 static const char tstr[] = "[|slip]";
50
51 static u_int lastlen[2][256];
52 static u_int lastconn = 255;
53
54 static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
55 static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
56
57 u_int
sl_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)58 sl_if_print(netdissect_options *ndo,
59 const struct pcap_pkthdr *h, const u_char *p)
60 {
61 register u_int caplen = h->caplen;
62 register u_int length = h->len;
63 register const struct ip *ip;
64
65 if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
66 ND_PRINT((ndo, "%s", tstr));
67 return (caplen);
68 }
69
70 length -= SLIP_HDRLEN;
71
72 ip = (struct ip *)(p + SLIP_HDRLEN);
73
74 if (ndo->ndo_eflag)
75 sliplink_print(ndo, p, ip, length);
76
77 switch (IP_V(ip)) {
78 case 4:
79 ip_print(ndo, (u_char *)ip, length);
80 break;
81 case 6:
82 ip6_print(ndo, (u_char *)ip, length);
83 break;
84 default:
85 ND_PRINT((ndo, "ip v%d", IP_V(ip)));
86 }
87
88 return (SLIP_HDRLEN);
89 }
90
91 u_int
sl_bsdos_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)92 sl_bsdos_if_print(netdissect_options *ndo,
93 const struct pcap_pkthdr *h, const u_char *p)
94 {
95 register u_int caplen = h->caplen;
96 register u_int length = h->len;
97 register const struct ip *ip;
98
99 if (caplen < SLIP_HDRLEN) {
100 ND_PRINT((ndo, "%s", tstr));
101 return (caplen);
102 }
103
104 length -= SLIP_HDRLEN;
105
106 ip = (struct ip *)(p + SLIP_HDRLEN);
107
108 #ifdef notdef
109 if (ndo->ndo_eflag)
110 sliplink_print(ndo, p, ip, length);
111 #endif
112
113 ip_print(ndo, (u_char *)ip, length);
114
115 return (SLIP_HDRLEN);
116 }
117
118 static void
sliplink_print(netdissect_options * ndo,register const u_char * p,register const struct ip * ip,register u_int length)119 sliplink_print(netdissect_options *ndo,
120 register const u_char *p, register const struct ip *ip,
121 register u_int length)
122 {
123 int dir;
124 u_int hlen;
125
126 dir = p[SLX_DIR];
127 ND_PRINT((ndo, dir == SLIPDIR_IN ? "I " : "O "));
128
129 if (ndo->ndo_nflag) {
130 /* XXX just dump the header */
131 register int i;
132
133 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
134 ND_PRINT((ndo, "%02x.", p[i]));
135 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
136 return;
137 }
138 switch (p[SLX_CHDR] & 0xf0) {
139
140 case TYPE_IP:
141 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
142 break;
143
144 case TYPE_UNCOMPRESSED_TCP:
145 /*
146 * The connection id is stored in the IP protocol field.
147 * Get it from the link layer since sl_uncompress_tcp()
148 * has restored the IP header copy to IPPROTO_TCP.
149 */
150 lastconn = ((struct ip *)&p[SLX_CHDR])->ip_p;
151 hlen = IP_HL(ip);
152 hlen += TH_OFF((struct tcphdr *)&((int *)ip)[hlen]);
153 lastlen[dir][lastconn] = length - (hlen << 2);
154 ND_PRINT((ndo, "utcp %d: ", lastconn));
155 break;
156
157 default:
158 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
159 compressed_sl_print(ndo, &p[SLX_CHDR], ip,
160 length, dir);
161 ND_PRINT((ndo, ": "));
162 } else
163 ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
164 }
165 }
166
167 static const u_char *
print_sl_change(netdissect_options * ndo,const char * str,register const u_char * cp)168 print_sl_change(netdissect_options *ndo,
169 const char *str, register const u_char *cp)
170 {
171 register u_int i;
172
173 if ((i = *cp++) == 0) {
174 i = EXTRACT_16BITS(cp);
175 cp += 2;
176 }
177 ND_PRINT((ndo, " %s%d", str, i));
178 return (cp);
179 }
180
181 static const u_char *
print_sl_winchange(netdissect_options * ndo,register const u_char * cp)182 print_sl_winchange(netdissect_options *ndo,
183 register const u_char *cp)
184 {
185 register short i;
186
187 if ((i = *cp++) == 0) {
188 i = EXTRACT_16BITS(cp);
189 cp += 2;
190 }
191 if (i >= 0)
192 ND_PRINT((ndo, " W+%d", i));
193 else
194 ND_PRINT((ndo, " W%d", i));
195 return (cp);
196 }
197
198 static void
compressed_sl_print(netdissect_options * ndo,const u_char * chdr,const struct ip * ip,u_int length,int dir)199 compressed_sl_print(netdissect_options *ndo,
200 const u_char *chdr, const struct ip *ip,
201 u_int length, int dir)
202 {
203 register const u_char *cp = chdr;
204 register u_int flags, hlen;
205
206 flags = *cp++;
207 if (flags & NEW_C) {
208 lastconn = *cp++;
209 ND_PRINT((ndo, "ctcp %d", lastconn));
210 } else
211 ND_PRINT((ndo, "ctcp *"));
212
213 /* skip tcp checksum */
214 cp += 2;
215
216 switch (flags & SPECIALS_MASK) {
217 case SPECIAL_I:
218 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
219 break;
220
221 case SPECIAL_D:
222 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
223 break;
224
225 default:
226 if (flags & NEW_U)
227 cp = print_sl_change(ndo, "U=", cp);
228 if (flags & NEW_W)
229 cp = print_sl_winchange(ndo, cp);
230 if (flags & NEW_A)
231 cp = print_sl_change(ndo, "A+", cp);
232 if (flags & NEW_S)
233 cp = print_sl_change(ndo, "S+", cp);
234 break;
235 }
236 if (flags & NEW_I)
237 cp = print_sl_change(ndo, "I+", cp);
238
239 /*
240 * 'hlen' is the length of the uncompressed TCP/IP header (in words).
241 * 'cp - chdr' is the length of the compressed header.
242 * 'length - hlen' is the amount of data in the packet.
243 */
244 hlen = IP_HL(ip);
245 hlen += TH_OFF((struct tcphdr *)&((int32_t *)ip)[hlen]);
246 lastlen[dir][lastconn] = length - (hlen << 2);
247 ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
248 }
249