1/*
2 * Copyright (c) 1988, 1989, 1990, 1991, 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
22#ifndef lint
23static const char rcsid[] _U_ =
24    "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.64 2004/04/30 16:42:14 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 <stdio.h>
34#include <string.h>
35
36#include "netdissect.h"
37#include "addrtoname.h"
38#include "ether.h"
39#include "ethertype.h"
40#include "extract.h"			/* must come after interface.h */
41
42/*
43 * Address Resolution Protocol.
44 *
45 * See RFC 826 for protocol description.  ARP packets are variable
46 * in size; the arphdr structure defines the fixed-length portion.
47 * Protocol type values are the same as those for 10 Mb/s Ethernet.
48 * It is followed by the variable-sized fields ar_sha, arp_spa,
49 * arp_tha and arp_tpa in that order, according to the lengths
50 * specified.  Field names used correspond to RFC 826.
51 */
52struct	arp_pkthdr {
53	u_short	ar_hrd;		/* format of hardware address */
54#define ARPHRD_ETHER 	1	/* ethernet hardware format */
55#define ARPHRD_IEEE802	6	/* token-ring hardware format */
56#define ARPHRD_ARCNET	7	/* arcnet hardware format */
57#define ARPHRD_FRELAY 	15	/* frame relay hardware format */
58#define ARPHRD_STRIP 	23	/* Ricochet Starmode Radio hardware format */
59#define ARPHRD_IEEE1394	24	/* IEEE 1394 (FireWire) hardware format */
60	u_short	ar_pro;		/* format of protocol address */
61	u_char	ar_hln;		/* length of hardware address */
62	u_char	ar_pln;		/* length of protocol address */
63	u_short	ar_op;		/* one of: */
64#define	ARPOP_REQUEST	1	/* request to resolve address */
65#define	ARPOP_REPLY	2	/* response to previous request */
66#define	ARPOP_REVREQUEST 3	/* request protocol address given hardware */
67#define	ARPOP_REVREPLY	4	/* response giving protocol address */
68#define ARPOP_INVREQUEST 8 	/* request to identify peer */
69#define ARPOP_INVREPLY	9	/* response identifying peer */
70/*
71 * The remaining fields are variable in size,
72 * according to the sizes above.
73 */
74#ifdef COMMENT_ONLY
75	u_char	ar_sha[];	/* sender hardware address */
76	u_char	ar_spa[];	/* sender protocol address */
77	u_char	ar_tha[];	/* target hardware address */
78	u_char	ar_tpa[];	/* target protocol address */
79#endif
80#define ar_sha(ap)	(((const u_char *)((ap)+1))+0)
81#define ar_spa(ap)	(((const u_char *)((ap)+1))+  (ap)->ar_hln)
82#define ar_tha(ap)	(((const u_char *)((ap)+1))+  (ap)->ar_hln+(ap)->ar_pln)
83#define ar_tpa(ap)	(((const u_char *)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln)
84};
85
86#define ARP_HDRLEN	8
87
88#define HRD(ap) EXTRACT_16BITS(&(ap)->ar_hrd)
89#define HLN(ap) ((ap)->ar_hln)
90#define PLN(ap) ((ap)->ar_pln)
91#define OP(ap)  EXTRACT_16BITS(&(ap)->ar_op)
92#define PRO(ap) EXTRACT_16BITS(&(ap)->ar_pro)
93#define SHA(ap) (ar_sha(ap))
94#define SPA(ap) (ar_spa(ap))
95#define THA(ap) (ar_tha(ap))
96#define TPA(ap) (ar_tpa(ap))
97
98/*
99 * ATM Address Resolution Protocol.
100 *
101 * See RFC 2225 for protocol description.  ATMARP packets are similar
102 * to ARP packets, except that there are no length fields for the
103 * protocol address - instead, there are type/length fields for
104 * the ATM number and subaddress - and the hardware addresses consist
105 * of an ATM number and an ATM subaddress.
106 */
107struct	atmarp_pkthdr {
108	u_short	aar_hrd;	/* format of hardware address */
109#define ARPHRD_ATM2225	19	/* ATM (RFC 2225) */
110	u_short	aar_pro;	/* format of protocol address */
111	u_char	aar_shtl;	/* length of source ATM number */
112	u_char	aar_sstl;	/* length of source ATM subaddress */
113#define ATMARP_IS_E164	0x40	/* bit in type/length for E.164 format */
114#define ATMARP_LEN_MASK	0x3F	/* length of {sub}address in type/length */
115	u_short	aar_op;		/* same as regular ARP */
116#define ATMARPOP_NAK	10	/* NAK */
117	u_char	aar_spln;	/* length of source protocol address */
118	u_char	aar_thtl;	/* length of target ATM number */
119	u_char	aar_tstl;	/* length of target ATM subaddress */
120	u_char	aar_tpln;	/* length of target protocol address */
121/*
122 * The remaining fields are variable in size,
123 * according to the sizes above.
124 */
125#ifdef COMMENT_ONLY
126	u_char	aar_sha[];	/* source ATM number */
127	u_char	aar_ssa[];	/* source ATM subaddress */
128	u_char	aar_spa[];	/* sender protocol address */
129	u_char	aar_tha[];	/* target ATM number */
130	u_char	aar_tsa[];	/* target ATM subaddress */
131	u_char	aar_tpa[];	/* target protocol address */
132#endif
133
134#define ATMHRD(ap)  EXTRACT_16BITS(&(ap)->aar_hrd)
135#define ATMSHLN(ap) ((ap)->aar_shtl & ATMARP_LEN_MASK)
136#define ATMSSLN(ap) ((ap)->aar_sstl & ATMARP_LEN_MASK)
137#define ATMSPLN(ap) ((ap)->aar_spln)
138#define ATMOP(ap)   EXTRACT_16BITS(&(ap)->aar_op)
139#define ATMPRO(ap)  EXTRACT_16BITS(&(ap)->aar_pro)
140#define ATMTHLN(ap) ((ap)->aar_thtl & ATMARP_LEN_MASK)
141#define ATMTSLN(ap) ((ap)->aar_tstl & ATMARP_LEN_MASK)
142#define ATMTPLN(ap) ((ap)->aar_tpln)
143#define aar_sha(ap)	((const u_char *)((ap)+1))
144#define aar_ssa(ap)	(aar_sha(ap) + ATMSHLN(ap))
145#define aar_spa(ap)	(aar_ssa(ap) + ATMSSLN(ap))
146#define aar_tha(ap)	(aar_spa(ap) + ATMSPLN(ap))
147#define aar_tsa(ap)	(aar_tha(ap) + ATMTHLN(ap))
148#define aar_tpa(ap)	(aar_tsa(ap) + ATMTSLN(ap))
149};
150
151#define ATMSHA(ap) (aar_sha(ap))
152#define ATMSSA(ap) (aar_ssa(ap))
153#define ATMSPA(ap) (aar_spa(ap))
154#define ATMTHA(ap) (aar_tha(ap))
155#define ATMTSA(ap) (aar_tsa(ap))
156#define ATMTPA(ap) (aar_tpa(ap))
157
158static u_char ezero[6];
159
160static void
161atmarp_addr_print(netdissect_options *ndo,
162		  const u_char *ha, u_int ha_len, const u_char *srca,
163    u_int srca_len)
164{
165	if (ha_len == 0)
166		ND_PRINT((ndo, "<No address>"));
167	else {
168		ND_PRINT((ndo, "%s", linkaddr_string(ha, ha_len)));
169		if (srca_len != 0)
170			ND_PRINT((ndo, ",%s",
171				  linkaddr_string(srca, srca_len)));
172	}
173}
174
175static void
176atmarp_print(netdissect_options *ndo,
177	     const u_char *bp, u_int length, u_int caplen)
178{
179	const struct atmarp_pkthdr *ap;
180	u_short pro, hrd, op;
181
182	ap = (const struct atmarp_pkthdr *)bp;
183	ND_TCHECK(*ap);
184
185	hrd = ATMHRD(ap);
186	pro = ATMPRO(ap);
187	op = ATMOP(ap);
188
189	if (!ND_TTEST2(*aar_tpa(ap), ATMTPLN(ap))) {
190		ND_PRINT((ndo, "truncated-atmarp"));
191		ND_DEFAULTPRINT((const u_char *)ap, length);
192		return;
193	}
194
195	if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
196	    ATMSPLN(ap) != 4 || ATMTPLN(ap) != 4) {
197		ND_PRINT((ndo, "atmarp-#%d for proto #%d (%d/%d) hardware #%d",
198			  op, pro, ATMSPLN(ap), ATMTPLN(ap), hrd));
199		return;
200	}
201	if (pro == ETHERTYPE_TRAIL)
202		ND_PRINT((ndo, "trailer-"));
203	switch (op) {
204
205	case ARPOP_REQUEST:
206		ND_PRINT((ndo, "arp who-has %s", ipaddr_string(ATMTPA(ap))));
207		if (ATMTHLN(ap) != 0) {
208			ND_PRINT((ndo, " ("));
209			atmarp_addr_print(ndo, ATMTHA(ap), ATMTHLN(ap),
210			    ATMTSA(ap), ATMTSLN(ap));
211			ND_PRINT((ndo, ")"));
212		}
213		ND_PRINT((ndo, " tell %s", ipaddr_string(ATMSPA(ap))));
214		break;
215
216	case ARPOP_REPLY:
217		ND_PRINT((ndo, "arp reply %s", ipaddr_string(ATMSPA(ap))));
218		ND_PRINT((ndo, " is-at "));
219		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap),
220		    ATMSSLN(ap));
221		break;
222
223	case ARPOP_INVREQUEST:
224		ND_PRINT((ndo, "invarp who-is "));
225		atmarp_addr_print(ndo, ATMTHA(ap), ATMTHLN(ap), ATMTSA(ap),
226		    ATMTSLN(ap));
227		ND_PRINT((ndo, " tell "));
228		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap),
229		    ATMSSLN(ap));
230		break;
231
232	case ARPOP_INVREPLY:
233		ND_PRINT((ndo, "invarp reply "));
234		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap),
235		    ATMSSLN(ap));
236		ND_PRINT((ndo, " at %s", ipaddr_string(ATMSPA(ap))));
237		break;
238
239	case ATMARPOP_NAK:
240		ND_PRINT((ndo, "nak reply for %s",
241			  ipaddr_string(ATMSPA(ap))));
242		break;
243
244	default:
245		ND_PRINT((ndo, "atmarp-#%d", op));
246		ND_DEFAULTPRINT((const u_char *)ap, caplen);
247		return;
248	}
249	return;
250trunc:
251	ND_PRINT((ndo, "[|atmarp]"));
252}
253
254void
255arp_print(netdissect_options *ndo,
256	  const u_char *bp, u_int length, u_int caplen)
257{
258	const struct arp_pkthdr *ap;
259	u_short pro, hrd, op;
260
261	ap = (const struct arp_pkthdr *)bp;
262	ND_TCHECK(*ap);
263	hrd = HRD(ap);
264	if (hrd == ARPHRD_ATM2225) {
265	        atmarp_print(ndo, bp, length, caplen);
266		return;
267	}
268	pro = PRO(ap);
269	op = OP(ap);
270
271	if (!ND_TTEST2(*ar_tpa(ap), PLN(ap))) {
272		ND_PRINT((ndo, "truncated-arp"));
273		ND_DEFAULTPRINT((const u_char *)ap, length);
274		return;
275	}
276
277	if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
278	    PLN(ap) != 4 || HLN(ap) == 0) {
279		ND_PRINT((ndo, "arp-#%d for proto #%d (%d) hardware #%d (%d)",
280			  op, pro, PLN(ap), hrd, HLN(ap)));
281		return;
282	}
283	if (pro == ETHERTYPE_TRAIL)
284		ND_PRINT((ndo, "trailer-"));
285	switch (op) {
286
287	case ARPOP_REQUEST:
288		ND_PRINT((ndo, "arp who-has %s", ipaddr_string(TPA(ap))));
289		if (memcmp((const char *)ezero, (const char *)THA(ap), HLN(ap)) != 0)
290			ND_PRINT((ndo, " (%s)",
291				  linkaddr_string(THA(ap), HLN(ap))));
292		ND_PRINT((ndo, " tell %s", ipaddr_string(SPA(ap))));
293		break;
294
295	case ARPOP_REPLY:
296		ND_PRINT((ndo, "arp reply %s", ipaddr_string(SPA(ap))));
297		ND_PRINT((ndo, " is-at %s", linkaddr_string(SHA(ap), HLN(ap))));
298		break;
299
300	case ARPOP_REVREQUEST:
301		ND_PRINT((ndo, "rarp who-is %s tell %s",
302			  linkaddr_string(THA(ap), HLN(ap)),
303			  linkaddr_string(SHA(ap), HLN(ap))));
304		break;
305
306	case ARPOP_REVREPLY:
307		ND_PRINT((ndo, "rarp reply %s at %s",
308			  linkaddr_string(THA(ap), HLN(ap)),
309			  ipaddr_string(TPA(ap))));
310		break;
311
312	case ARPOP_INVREQUEST:
313		ND_PRINT((ndo, "invarp who-is %s tell %s",
314			  linkaddr_string(THA(ap), HLN(ap)),
315			  linkaddr_string(SHA(ap), HLN(ap))));
316		break;
317
318	case ARPOP_INVREPLY:
319		ND_PRINT((ndo,"invarp reply %s at %s",
320			  linkaddr_string(THA(ap), HLN(ap)),
321			  ipaddr_string(TPA(ap))));
322		break;
323
324	default:
325		ND_PRINT((ndo, "arp-#%d", op));
326		ND_DEFAULTPRINT((const u_char *)ap, caplen);
327		return;
328	}
329	if (hrd != ARPHRD_ETHER)
330		ND_PRINT((ndo, " hardware #%d", hrd));
331	return;
332trunc:
333	ND_PRINT((ndo, "[|arp]"));
334}
335
336/*
337 * Local Variables:
338 * c-style: bsd
339 * End:
340 */
341
342