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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 #ifndef lint
23 static const char rcsid[] _U_ =
24     "@(#) $Header: /tcpdump/master/tcpdump/print-sl.c,v 1.65 2005-04-06 21:32:42 mcr Exp $ (LBL)";
25 #endif
26 
27 #ifdef HAVE_CONFIG_H
28 #include "config.h"
29 #endif
30 
31 #include <tcpdump-stdinc.h>
32 
33 #include <pcap.h>
34 #include <stdio.h>
35 
36 #include "interface.h"
37 #include "addrtoname.h"
38 #include "extract.h"			/* must come after interface.h */
39 
40 #include "ip.h"
41 #include "tcp.h"
42 #include "slip.h"
43 #include "slcompress.h"
44 
45 static u_int lastlen[2][256];
46 static u_int lastconn = 255;
47 
48 static void sliplink_print(const u_char *, const struct ip *, u_int);
49 static void compressed_sl_print(const u_char *, const struct ip *, u_int, int);
50 
51 u_int
sl_if_print(const struct pcap_pkthdr * h,const u_char * p)52 sl_if_print(const struct pcap_pkthdr *h, const u_char *p)
53 {
54 	register u_int caplen = h->caplen;
55 	register u_int length = h->len;
56 	register const struct ip *ip;
57 
58 	if (caplen < SLIP_HDRLEN) {
59 		printf("[|slip]");
60 		return (caplen);
61 	}
62 
63 	length -= SLIP_HDRLEN;
64 
65 	ip = (struct ip *)(p + SLIP_HDRLEN);
66 
67 	if (eflag)
68 		sliplink_print(p, ip, length);
69 
70 	switch (IP_V(ip)) {
71 	case 4:
72 	        ip_print(gndo, (u_char *)ip, length);
73 		break;
74 #ifdef INET6
75 	case 6:
76 		ip6_print(gndo, (u_char *)ip, length);
77 		break;
78 #endif
79 	default:
80 		printf ("ip v%d", IP_V(ip));
81 	}
82 
83 	return (SLIP_HDRLEN);
84 }
85 
86 u_int
sl_bsdos_if_print(const struct pcap_pkthdr * h,const u_char * p)87 sl_bsdos_if_print(const struct pcap_pkthdr *h, const u_char *p)
88 {
89 	register u_int caplen = h->caplen;
90 	register u_int length = h->len;
91 	register const struct ip *ip;
92 
93 	if (caplen < SLIP_HDRLEN) {
94 		printf("[|slip]");
95 		return (caplen);
96 	}
97 
98 	length -= SLIP_HDRLEN;
99 
100 	ip = (struct ip *)(p + SLIP_HDRLEN);
101 
102 #ifdef notdef
103 	if (eflag)
104 		sliplink_print(p, ip, length);
105 #endif
106 
107 	ip_print(gndo, (u_char *)ip, length);
108 
109 	return (SLIP_HDRLEN);
110 }
111 
112 static void
sliplink_print(register const u_char * p,register const struct ip * ip,register u_int length)113 sliplink_print(register const u_char *p, register const struct ip *ip,
114 	       register u_int length)
115 {
116 	int dir;
117 	u_int hlen;
118 
119 	dir = p[SLX_DIR];
120 	putchar(dir == SLIPDIR_IN ? 'I' : 'O');
121 	putchar(' ');
122 
123 	if (nflag) {
124 		/* XXX just dump the header */
125 		register int i;
126 
127 		for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
128 			printf("%02x.", p[i]);
129 		printf("%02x: ", p[SLX_CHDR + CHDR_LEN - 1]);
130 		return;
131 	}
132 	switch (p[SLX_CHDR] & 0xf0) {
133 
134 	case TYPE_IP:
135 		printf("ip %d: ", length + SLIP_HDRLEN);
136 		break;
137 
138 	case TYPE_UNCOMPRESSED_TCP:
139 		/*
140 		 * The connection id is stored in the IP protocol field.
141 		 * Get it from the link layer since sl_uncompress_tcp()
142 		 * has restored the IP header copy to IPPROTO_TCP.
143 		 */
144 		lastconn = ((struct ip *)&p[SLX_CHDR])->ip_p;
145 		hlen = IP_HL(ip);
146 		hlen += TH_OFF((struct tcphdr *)&((int *)ip)[hlen]);
147 		lastlen[dir][lastconn] = length - (hlen << 2);
148 		printf("utcp %d: ", lastconn);
149 		break;
150 
151 	default:
152 		if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
153 			compressed_sl_print(&p[SLX_CHDR], ip,
154 			    length, dir);
155 			printf(": ");
156 		} else
157 			printf("slip-%d!: ", p[SLX_CHDR]);
158 	}
159 }
160 
161 static const u_char *
print_sl_change(const char * str,register const u_char * cp)162 print_sl_change(const char *str, register const u_char *cp)
163 {
164 	register u_int i;
165 
166 	if ((i = *cp++) == 0) {
167 		i = EXTRACT_16BITS(cp);
168 		cp += 2;
169 	}
170 	printf(" %s%d", str, i);
171 	return (cp);
172 }
173 
174 static const u_char *
print_sl_winchange(register const u_char * cp)175 print_sl_winchange(register const u_char *cp)
176 {
177 	register short i;
178 
179 	if ((i = *cp++) == 0) {
180 		i = EXTRACT_16BITS(cp);
181 		cp += 2;
182 	}
183 	if (i >= 0)
184 		printf(" W+%d", i);
185 	else
186 		printf(" W%d", i);
187 	return (cp);
188 }
189 
190 static void
compressed_sl_print(const u_char * chdr,const struct ip * ip,u_int length,int dir)191 compressed_sl_print(const u_char *chdr, const struct ip *ip,
192 		    u_int length, int dir)
193 {
194 	register const u_char *cp = chdr;
195 	register u_int flags, hlen;
196 
197 	flags = *cp++;
198 	if (flags & NEW_C) {
199 		lastconn = *cp++;
200 		printf("ctcp %d", lastconn);
201 	} else
202 		printf("ctcp *");
203 
204 	/* skip tcp checksum */
205 	cp += 2;
206 
207 	switch (flags & SPECIALS_MASK) {
208 	case SPECIAL_I:
209 		printf(" *SA+%d", lastlen[dir][lastconn]);
210 		break;
211 
212 	case SPECIAL_D:
213 		printf(" *S+%d", lastlen[dir][lastconn]);
214 		break;
215 
216 	default:
217 		if (flags & NEW_U)
218 			cp = print_sl_change("U=", cp);
219 		if (flags & NEW_W)
220 			cp = print_sl_winchange(cp);
221 		if (flags & NEW_A)
222 			cp = print_sl_change("A+", cp);
223 		if (flags & NEW_S)
224 			cp = print_sl_change("S+", cp);
225 		break;
226 	}
227 	if (flags & NEW_I)
228 		cp = print_sl_change("I+", cp);
229 
230 	/*
231 	 * 'hlen' is the length of the uncompressed TCP/IP header (in words).
232 	 * 'cp - chdr' is the length of the compressed header.
233 	 * 'length - hlen' is the amount of data in the packet.
234 	 */
235 	hlen = IP_HL(ip);
236 	hlen += TH_OFF((struct tcphdr *)&((int32_t *)ip)[hlen]);
237 	lastlen[dir][lastconn] = length - (hlen << 2);
238 	printf(" %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr));
239 }
240