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