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 #include <sys/cdefs.h>
23 #ifndef lint
24 __RCSID("$NetBSD: print-sl.c,v 1.5 2015/03/31 21:59:35 christos Exp $");
25 #endif
26
27 #define NETDISSECT_REWORKED
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31
32 #include <tcpdump-stdinc.h>
33
34 #include "interface.h"
35 #include "extract.h" /* must come after interface.h */
36
37 #include "ip.h"
38 #include "tcp.h"
39 #include "slcompress.h"
40
41 /*
42 * definitions of the pseudo- link-level header attached to slip
43 * packets grabbed by the packet filter (bpf) traffic monitor.
44 */
45 #define SLIP_HDRLEN 16
46
47 #define SLX_DIR 0
48 #define SLX_CHDR 1
49 #define CHDR_LEN 15
50
51 #define SLIPDIR_IN 0
52 #define SLIPDIR_OUT 1
53
54 static const char tstr[] = "[|slip]";
55
56 static u_int lastlen[2][256];
57 static u_int lastconn = 255;
58
59 static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
60 static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
61
62 u_int
sl_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)63 sl_if_print(netdissect_options *ndo,
64 const struct pcap_pkthdr *h, const u_char *p)
65 {
66 register u_int caplen = h->caplen;
67 register u_int length = h->len;
68 register const struct ip *ip;
69
70 if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
71 ND_PRINT((ndo, "%s", tstr));
72 return (caplen);
73 }
74
75 length -= SLIP_HDRLEN;
76
77 ip = (struct ip *)(p + SLIP_HDRLEN);
78
79 if (ndo->ndo_eflag)
80 sliplink_print(ndo, p, ip, length);
81
82 switch (IP_V(ip)) {
83 case 4:
84 ip_print(ndo, (u_char *)ip, length);
85 break;
86 case 6:
87 ip6_print(ndo, (u_char *)ip, length);
88 break;
89 default:
90 ND_PRINT((ndo, "ip v%d", IP_V(ip)));
91 }
92
93 return (SLIP_HDRLEN);
94 }
95
96 u_int
sl_bsdos_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)97 sl_bsdos_if_print(netdissect_options *ndo,
98 const struct pcap_pkthdr *h, const u_char *p)
99 {
100 register u_int caplen = h->caplen;
101 register u_int length = h->len;
102 register const struct ip *ip;
103
104 if (caplen < SLIP_HDRLEN) {
105 ND_PRINT((ndo, "%s", tstr));
106 return (caplen);
107 }
108
109 length -= SLIP_HDRLEN;
110
111 ip = (struct ip *)(p + SLIP_HDRLEN);
112
113 #ifdef notdef
114 if (ndo->ndo_eflag)
115 sliplink_print(ndo, p, ip, length);
116 #endif
117
118 ip_print(ndo, (u_char *)ip, length);
119
120 return (SLIP_HDRLEN);
121 }
122
123 static void
sliplink_print(netdissect_options * ndo,register const u_char * p,register const struct ip * ip,register u_int length)124 sliplink_print(netdissect_options *ndo,
125 register const u_char *p, register const struct ip *ip,
126 register u_int length)
127 {
128 int dir;
129 u_int hlen;
130
131 dir = p[SLX_DIR];
132 ND_PRINT((ndo, dir == SLIPDIR_IN ? "I " : "O "));
133
134 if (ndo->ndo_nflag) {
135 /* XXX just dump the header */
136 register int i;
137
138 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
139 ND_PRINT((ndo, "%02x.", p[i]));
140 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
141 return;
142 }
143 switch (p[SLX_CHDR] & 0xf0) {
144
145 case TYPE_IP:
146 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
147 break;
148
149 case TYPE_UNCOMPRESSED_TCP:
150 /*
151 * The connection id is stored in the IP protocol field.
152 * Get it from the link layer since sl_uncompress_tcp()
153 * has restored the IP header copy to IPPROTO_TCP.
154 */
155 lastconn = ((struct ip *)&p[SLX_CHDR])->ip_p;
156 hlen = IP_HL(ip);
157 hlen += TH_OFF((struct tcphdr *)&((int *)ip)[hlen]);
158 lastlen[dir][lastconn] = length - (hlen << 2);
159 ND_PRINT((ndo, "utcp %d: ", lastconn));
160 break;
161
162 default:
163 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
164 compressed_sl_print(ndo, &p[SLX_CHDR], ip,
165 length, dir);
166 ND_PRINT((ndo, ": "));
167 } else
168 ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
169 }
170 }
171
172 static const u_char *
print_sl_change(netdissect_options * ndo,const char * str,register const u_char * cp)173 print_sl_change(netdissect_options *ndo,
174 const char *str, register const u_char *cp)
175 {
176 register u_int i;
177
178 if ((i = *cp++) == 0) {
179 i = EXTRACT_16BITS(cp);
180 cp += 2;
181 }
182 ND_PRINT((ndo, " %s%d", str, i));
183 return (cp);
184 }
185
186 static const u_char *
print_sl_winchange(netdissect_options * ndo,register const u_char * cp)187 print_sl_winchange(netdissect_options *ndo,
188 register const u_char *cp)
189 {
190 register short i;
191
192 if ((i = *cp++) == 0) {
193 i = EXTRACT_16BITS(cp);
194 cp += 2;
195 }
196 if (i >= 0)
197 ND_PRINT((ndo, " W+%d", i));
198 else
199 ND_PRINT((ndo, " W%d", i));
200 return (cp);
201 }
202
203 static void
compressed_sl_print(netdissect_options * ndo,const u_char * chdr,const struct ip * ip,u_int length,int dir)204 compressed_sl_print(netdissect_options *ndo,
205 const u_char *chdr, const struct ip *ip,
206 u_int length, int dir)
207 {
208 register const u_char *cp = chdr;
209 register u_int flags, hlen;
210
211 flags = *cp++;
212 if (flags & NEW_C) {
213 lastconn = *cp++;
214 ND_PRINT((ndo, "ctcp %d", lastconn));
215 } else
216 ND_PRINT((ndo, "ctcp *"));
217
218 /* skip tcp checksum */
219 cp += 2;
220
221 switch (flags & SPECIALS_MASK) {
222 case SPECIAL_I:
223 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
224 break;
225
226 case SPECIAL_D:
227 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
228 break;
229
230 default:
231 if (flags & NEW_U)
232 cp = print_sl_change(ndo, "U=", cp);
233 if (flags & NEW_W)
234 cp = print_sl_winchange(ndo, cp);
235 if (flags & NEW_A)
236 cp = print_sl_change(ndo, "A+", cp);
237 if (flags & NEW_S)
238 cp = print_sl_change(ndo, "S+", cp);
239 break;
240 }
241 if (flags & NEW_I)
242 cp = print_sl_change(ndo, "I+", cp);
243
244 /*
245 * 'hlen' is the length of the uncompressed TCP/IP header (in words).
246 * 'cp - chdr' is the length of the compressed header.
247 * 'length - hlen' is the amount of data in the packet.
248 */
249 hlen = IP_HL(ip);
250 hlen += TH_OFF((struct tcphdr *)&((int32_t *)ip)[hlen]);
251 lastlen[dir][lastconn] = length - (hlen << 2);
252 ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
253 }
254