xref: /freebsd/contrib/tcpdump/print-llc.c (revision 4cf49a43559ed9fdad601bdcccd2c55963008675)
1 /*
2  * Copyright (c) 1992, 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  * Code by Matt Thomas, Digital Equipment Corporation
22  *	with an awful lot of hacking by Jeffrey Mogul, DECWRL
23  */
24 
25 #ifndef lint
26 static const char rcsid[] =
27     "@(#) $Header: print-llc.c,v 1.24 97/01/01 20:56:48 leres Exp $";
28 #endif
29 
30 #include <sys/param.h>
31 #include <sys/time.h>
32 
33 #include <netinet/in.h>
34 
35 #include <ctype.h>
36 #include <netdb.h>
37 #include <stdio.h>
38 #include <string.h>
39 
40 #include "interface.h"
41 #include "addrtoname.h"
42 #include "extract.h"			/* must come after interface.h */
43 
44 #include "llc.h"
45 
46 static struct tok cmd2str[] = {
47 	{ LLC_UI,	"ui" },
48 	{ LLC_TEST,	"test" },
49 	{ LLC_XID,	"xid" },
50 	{ LLC_UA,	"ua" },
51 	{ LLC_DISC,	"disc" },
52 	{ LLC_DM,	"dm" },
53 	{ LLC_SABME,	"sabme" },
54 	{ LLC_FRMR,	"frmr" },
55 	{ 0,		NULL }
56 };
57 
58 /*
59  * Returns non-zero IFF it succeeds in printing the header
60  */
61 int
62 llc_print(const u_char *p, u_int length, u_int caplen,
63 	  const u_char *esrc, const u_char *edst)
64 {
65 	struct llc llc;
66 	register u_short et;
67 	register int ret;
68 
69 	if (caplen < 3) {
70 		(void)printf("[|llc]");
71 		default_print((u_char *)p, caplen);
72 		return(0);
73 	}
74 
75 	/* Watch out for possible alignment problems */
76 	memcpy((char *)&llc, (char *)p, min(caplen, sizeof(llc)));
77 
78 	if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
79 		ipx_print(p, length);
80 		return (1);
81 	}
82 #ifdef notyet
83 	else if (p[0] == 0xf0 && p[1] == 0xf0)
84 		netbios_print(p, length);
85 #endif
86 	if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
87 	    && llc.llcui == LLC_UI) {
88 		isoclns_print(p + 3, length - 3, caplen - 3, esrc, edst);
89 		return (1);
90 	}
91 
92 	if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
93 	    && llc.llcui == LLC_UI) {
94 		if (caplen < sizeof(llc)) {
95 		    (void)printf("[|llc-snap]");
96 		    default_print((u_char *)p, caplen);
97 		    return (0);
98 		}
99 		if (vflag)
100 			(void)printf("snap %s ", protoid_string(llc.llcpi));
101 
102 		caplen -= sizeof(llc);
103 		length -= sizeof(llc);
104 		p += sizeof(llc);
105 
106 		/* This is an encapsulated Ethernet packet */
107 		et = EXTRACT_16BITS(&llc.ethertype[0]);
108 		ret = ether_encap_print(et, p, length, caplen);
109 		if (ret)
110 			return (ret);
111 	}
112 
113 	if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
114 		if (eflag)
115 			(void)printf("%s ", llcsap_string(llc.dsap));
116 		else
117 			(void)printf("%s > %s %s ",
118 					etheraddr_string(esrc),
119 					etheraddr_string(edst),
120 					llcsap_string(llc.dsap));
121 	} else {
122 		if (eflag)
123 			(void)printf("%s > %s ",
124 				llcsap_string(llc.ssap & ~LLC_GSAP),
125 				llcsap_string(llc.dsap));
126 		else
127 			(void)printf("%s %s > %s %s ",
128 				etheraddr_string(esrc),
129 				llcsap_string(llc.ssap & ~LLC_GSAP),
130 				etheraddr_string(edst),
131 				llcsap_string(llc.dsap));
132 	}
133 
134 	if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
135 		const char *m;
136 		char f;
137 		m = tok2str(cmd2str, "%02x", LLC_U_CMD(llc.llcu));
138 		switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
139 		    case 0:			f = 'C'; break;
140 		    case LLC_GSAP:		f = 'R'; break;
141 		    case LLC_U_POLL:		f = 'P'; break;
142 		    case LLC_GSAP|LLC_U_POLL:	f = 'F'; break;
143 		    default:			f = '?'; break;
144 		}
145 
146 		printf("%s/%c", m, f);
147 
148 		p += 3;
149 		length -= 3;
150 		caplen -= 3;
151 
152 		if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
153 		    if (*p == LLC_XID_FI) {
154 			printf(": %02x %02x", p[1], p[2]);
155 			p += 3;
156 			length -= 3;
157 			caplen -= 3;
158 		    }
159 		}
160 	} else {
161 		char f;
162 		llc.llcis = ntohs(llc.llcis);
163 		switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
164 		    case 0:			f = 'C'; break;
165 		    case LLC_GSAP:		f = 'R'; break;
166 		    case LLC_U_POLL:		f = 'P'; break;
167 		    case LLC_GSAP|LLC_U_POLL:	f = 'F'; break;
168 		    default:			f = '?'; break;
169 		}
170 
171 		if ((llc.llcu & LLC_S_FMT) == LLC_S_FMT) {
172 			static char *llc_s[] = { "rr", "rej", "rnr", "03" };
173 			(void)printf("%s (r=%d,%c)",
174 				llc_s[LLC_S_CMD(llc.llcis)],
175 				LLC_IS_NR(llc.llcis),
176 				f);
177 		} else {
178 			(void)printf("I (s=%d,r=%d,%c)",
179 				LLC_I_NS(llc.llcis),
180 				LLC_IS_NR(llc.llcis),
181 				f);
182 		}
183 		p += 4;
184 		length -= 4;
185 		caplen -= 4;
186 	}
187 	(void)printf(" len=%d", length);
188 	if (caplen > 0 && !qflag) {
189 		default_print_unaligned(p, caplen);
190 	}
191 	return(1);
192 }
193