xref: /freebsd/contrib/tcpdump/print-sl.c (revision 63d1fd5970ec814904aa0f4580b10a0d302d08b2)
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  * $FreeBSD$
22  */
23 
24 #define NETDISSECT_REWORKED
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28 
29 #include <tcpdump-stdinc.h>
30 
31 #include "interface.h"
32 #include "extract.h"			/* must come after interface.h */
33 
34 #include "ip.h"
35 #include "tcp.h"
36 #include "slcompress.h"
37 
38 /*
39  * definitions of the pseudo- link-level header attached to slip
40  * packets grabbed by the packet filter (bpf) traffic monitor.
41  */
42 #define SLIP_HDRLEN 16
43 
44 #define SLX_DIR 0
45 #define SLX_CHDR 1
46 #define CHDR_LEN 15
47 
48 #define SLIPDIR_IN 0
49 #define SLIPDIR_OUT 1
50 
51 static const char tstr[] = "[|slip]";
52 
53 static u_int lastlen[2][256];
54 static u_int lastconn = 255;
55 
56 static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
57 static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
58 
59 u_int
60 sl_if_print(netdissect_options *ndo,
61             const struct pcap_pkthdr *h, const u_char *p)
62 {
63 	register u_int caplen = h->caplen;
64 	register u_int length = h->len;
65 	register const struct ip *ip;
66 
67 	if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
68 		ND_PRINT((ndo, "%s", tstr));
69 		return (caplen);
70 	}
71 
72 	length -= SLIP_HDRLEN;
73 
74 	ip = (struct ip *)(p + SLIP_HDRLEN);
75 
76 	if (ndo->ndo_eflag)
77 		sliplink_print(ndo, p, ip, length);
78 
79 	switch (IP_V(ip)) {
80 	case 4:
81 	        ip_print(ndo, (u_char *)ip, length);
82 		break;
83 	case 6:
84 		ip6_print(ndo, (u_char *)ip, length);
85 		break;
86 	default:
87 		ND_PRINT((ndo, "ip v%d", IP_V(ip)));
88 	}
89 
90 	return (SLIP_HDRLEN);
91 }
92 
93 u_int
94 sl_bsdos_if_print(netdissect_options *ndo,
95                   const struct pcap_pkthdr *h, const u_char *p)
96 {
97 	register u_int caplen = h->caplen;
98 	register u_int length = h->len;
99 	register const struct ip *ip;
100 
101 	if (caplen < SLIP_HDRLEN) {
102 		ND_PRINT((ndo, "%s", tstr));
103 		return (caplen);
104 	}
105 
106 	length -= SLIP_HDRLEN;
107 
108 	ip = (struct ip *)(p + SLIP_HDRLEN);
109 
110 #ifdef notdef
111 	if (ndo->ndo_eflag)
112 		sliplink_print(ndo, p, ip, length);
113 #endif
114 
115 	ip_print(ndo, (u_char *)ip, length);
116 
117 	return (SLIP_HDRLEN);
118 }
119 
120 static void
121 sliplink_print(netdissect_options *ndo,
122                register const u_char *p, register const struct ip *ip,
123                register u_int length)
124 {
125 	int dir;
126 	u_int hlen;
127 
128 	dir = p[SLX_DIR];
129 	ND_PRINT((ndo, dir == SLIPDIR_IN ? "I " : "O "));
130 
131 	if (ndo->ndo_nflag) {
132 		/* XXX just dump the header */
133 		register int i;
134 
135 		for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
136 			ND_PRINT((ndo, "%02x.", p[i]));
137 		ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
138 		return;
139 	}
140 	switch (p[SLX_CHDR] & 0xf0) {
141 
142 	case TYPE_IP:
143 		ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
144 		break;
145 
146 	case TYPE_UNCOMPRESSED_TCP:
147 		/*
148 		 * The connection id is stored in the IP protocol field.
149 		 * Get it from the link layer since sl_uncompress_tcp()
150 		 * has restored the IP header copy to IPPROTO_TCP.
151 		 */
152 		lastconn = ((struct ip *)&p[SLX_CHDR])->ip_p;
153 		hlen = IP_HL(ip);
154 		hlen += TH_OFF((struct tcphdr *)&((int *)ip)[hlen]);
155 		lastlen[dir][lastconn] = length - (hlen << 2);
156 		ND_PRINT((ndo, "utcp %d: ", lastconn));
157 		break;
158 
159 	default:
160 		if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
161 			compressed_sl_print(ndo, &p[SLX_CHDR], ip,
162 			    length, dir);
163 			ND_PRINT((ndo, ": "));
164 		} else
165 			ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
166 	}
167 }
168 
169 static const u_char *
170 print_sl_change(netdissect_options *ndo,
171                 const char *str, register const u_char *cp)
172 {
173 	register u_int i;
174 
175 	if ((i = *cp++) == 0) {
176 		i = EXTRACT_16BITS(cp);
177 		cp += 2;
178 	}
179 	ND_PRINT((ndo, " %s%d", str, i));
180 	return (cp);
181 }
182 
183 static const u_char *
184 print_sl_winchange(netdissect_options *ndo,
185                    register const u_char *cp)
186 {
187 	register short i;
188 
189 	if ((i = *cp++) == 0) {
190 		i = EXTRACT_16BITS(cp);
191 		cp += 2;
192 	}
193 	if (i >= 0)
194 		ND_PRINT((ndo, " W+%d", i));
195 	else
196 		ND_PRINT((ndo, " W%d", i));
197 	return (cp);
198 }
199 
200 static void
201 compressed_sl_print(netdissect_options *ndo,
202                     const u_char *chdr, const struct ip *ip,
203                     u_int length, int dir)
204 {
205 	register const u_char *cp = chdr;
206 	register u_int flags, hlen;
207 
208 	flags = *cp++;
209 	if (flags & NEW_C) {
210 		lastconn = *cp++;
211 		ND_PRINT((ndo, "ctcp %d", lastconn));
212 	} else
213 		ND_PRINT((ndo, "ctcp *"));
214 
215 	/* skip tcp checksum */
216 	cp += 2;
217 
218 	switch (flags & SPECIALS_MASK) {
219 	case SPECIAL_I:
220 		ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
221 		break;
222 
223 	case SPECIAL_D:
224 		ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
225 		break;
226 
227 	default:
228 		if (flags & NEW_U)
229 			cp = print_sl_change(ndo, "U=", cp);
230 		if (flags & NEW_W)
231 			cp = print_sl_winchange(ndo, cp);
232 		if (flags & NEW_A)
233 			cp = print_sl_change(ndo, "A+", cp);
234 		if (flags & NEW_S)
235 			cp = print_sl_change(ndo, "S+", cp);
236 		break;
237 	}
238 	if (flags & NEW_I)
239 		cp = print_sl_change(ndo, "I+", cp);
240 
241 	/*
242 	 * 'hlen' is the length of the uncompressed TCP/IP header (in words).
243 	 * 'cp - chdr' is the length of the compressed header.
244 	 * 'length - hlen' is the amount of data in the packet.
245 	 */
246 	hlen = IP_HL(ip);
247 	hlen += TH_OFF((struct tcphdr *)&((int32_t *)ip)[hlen]);
248 	lastlen[dir][lastconn] = length - (hlen << 2);
249 	ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
250 }
251