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 * $FreeBSD$
22 */
23
24#ifndef lint
25static const char rcsid[] _U_ =
26    "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.66 2006-03-03 22:53:21 hannes Exp $ (LBL)";
27#endif
28
29#ifdef HAVE_CONFIG_H
30#include "config.h"
31#endif
32
33#include <tcpdump-stdinc.h>
34
35#include <stdio.h>
36#include <string.h>
37
38#include "netdissect.h"
39#include "addrtoname.h"
40#include "ether.h"
41#include "ethertype.h"
42#include "extract.h"			/* must come after interface.h */
43
44/*
45 * Address Resolution Protocol.
46 *
47 * See RFC 826 for protocol description.  ARP packets are variable
48 * in size; the arphdr structure defines the fixed-length portion.
49 * Protocol type values are the same as those for 10 Mb/s Ethernet.
50 * It is followed by the variable-sized fields ar_sha, arp_spa,
51 * arp_tha and arp_tpa in that order, according to the lengths
52 * specified.  Field names used correspond to RFC 826.
53 */
54struct  arp_pkthdr {
55        u_short ar_hrd;         /* format of hardware address */
56#define ARPHRD_ETHER    1       /* ethernet hardware format */
57#define ARPHRD_IEEE802  6       /* token-ring hardware format */
58#define ARPHRD_ARCNET   7       /* arcnet hardware format */
59#define ARPHRD_FRELAY   15      /* frame relay hardware format */
60#define ARPHRD_ATM2225  19      /* ATM (RFC 2225) */
61#define ARPHRD_STRIP    23      /* Ricochet Starmode Radio hardware format */
62#define ARPHRD_IEEE1394 24      /* IEEE 1394 (FireWire) hardware format */
63        u_short ar_pro;         /* format of protocol address */
64        u_char  ar_hln;         /* length of hardware address */
65        u_char  ar_pln;         /* length of protocol address */
66        u_short ar_op;          /* one of: */
67#define ARPOP_REQUEST   1       /* request to resolve address */
68#define ARPOP_REPLY     2       /* response to previous request */
69#define ARPOP_REVREQUEST 3      /* request protocol address given hardware */
70#define ARPOP_REVREPLY  4       /* response giving protocol address */
71#define ARPOP_INVREQUEST 8      /* request to identify peer */
72#define ARPOP_INVREPLY  9       /* response identifying peer */
73#define ARPOP_NAK       10      /* NAK - only valif for ATM ARP */
74
75/*
76 * The remaining fields are variable in size,
77 * according to the sizes above.
78 */
79#ifdef COMMENT_ONLY
80	u_char	ar_sha[];	/* sender hardware address */
81	u_char	ar_spa[];	/* sender protocol address */
82	u_char	ar_tha[];	/* target hardware address */
83	u_char	ar_tpa[];	/* target protocol address */
84#endif
85#define ar_sha(ap)	(((const u_char *)((ap)+1))+0)
86#define ar_spa(ap)	(((const u_char *)((ap)+1))+  (ap)->ar_hln)
87#define ar_tha(ap)	(((const u_char *)((ap)+1))+  (ap)->ar_hln+(ap)->ar_pln)
88#define ar_tpa(ap)	(((const u_char *)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln)
89};
90
91#define ARP_HDRLEN	8
92
93#define HRD(ap) EXTRACT_16BITS(&(ap)->ar_hrd)
94#define HRD_LEN(ap) ((ap)->ar_hln)
95#define PROTO_LEN(ap) ((ap)->ar_pln)
96#define OP(ap)  EXTRACT_16BITS(&(ap)->ar_op)
97#define PRO(ap) EXTRACT_16BITS(&(ap)->ar_pro)
98#define SHA(ap) (ar_sha(ap))
99#define SPA(ap) (ar_spa(ap))
100#define THA(ap) (ar_tha(ap))
101#define TPA(ap) (ar_tpa(ap))
102
103
104struct tok arpop_values[] = {
105    { ARPOP_REQUEST, "Request" },
106    { ARPOP_REPLY, "Reply" },
107    { ARPOP_REVREQUEST, "Reverse Request" },
108    { ARPOP_REVREPLY, "Reverse Reply" },
109    { ARPOP_INVREQUEST, "Inverse Request" },
110    { ARPOP_INVREPLY, "Inverse Reply" },
111    { ARPOP_NAK, "NACK Reply" },
112    { 0, NULL }
113};
114
115struct tok arphrd_values[] = {
116    { ARPHRD_ETHER, "Ethernet" },
117    { ARPHRD_IEEE802, "TokenRing" },
118    { ARPHRD_ARCNET, "ArcNet" },
119    { ARPHRD_FRELAY, "FrameRelay" },
120    { ARPHRD_STRIP, "Strip" },
121    { ARPHRD_IEEE1394, "IEEE 1394" },
122    { ARPHRD_ATM2225, "ATM" },
123    { 0, NULL }
124};
125
126/*
127 * ATM Address Resolution Protocol.
128 *
129 * See RFC 2225 for protocol description.  ATMARP packets are similar
130 * to ARP packets, except that there are no length fields for the
131 * protocol address - instead, there are type/length fields for
132 * the ATM number and subaddress - and the hardware addresses consist
133 * of an ATM number and an ATM subaddress.
134 */
135struct  atmarp_pkthdr {
136        u_short aar_hrd;        /* format of hardware address */
137        u_short aar_pro;        /* format of protocol address */
138        u_char  aar_shtl;       /* length of source ATM number */
139        u_char  aar_sstl;       /* length of source ATM subaddress */
140#define ATMARP_IS_E164  0x40    /* bit in type/length for E.164 format */
141#define ATMARP_LEN_MASK 0x3F    /* length of {sub}address in type/length */
142        u_short aar_op;         /* same as regular ARP */
143        u_char  aar_spln;       /* length of source protocol address */
144        u_char  aar_thtl;       /* length of target ATM number */
145        u_char  aar_tstl;       /* length of target ATM subaddress */
146        u_char  aar_tpln;       /* length of target protocol address */
147/*
148 * The remaining fields are variable in size,
149 * according to the sizes above.
150 */
151#ifdef COMMENT_ONLY
152	u_char	aar_sha[];	/* source ATM number */
153	u_char	aar_ssa[];	/* source ATM subaddress */
154	u_char	aar_spa[];	/* sender protocol address */
155	u_char	aar_tha[];	/* target ATM number */
156	u_char	aar_tsa[];	/* target ATM subaddress */
157	u_char	aar_tpa[];	/* target protocol address */
158#endif
159
160#define ATMHRD(ap)  EXTRACT_16BITS(&(ap)->aar_hrd)
161#define ATMSHRD_LEN(ap) ((ap)->aar_shtl & ATMARP_LEN_MASK)
162#define ATMSSLN(ap) ((ap)->aar_sstl & ATMARP_LEN_MASK)
163#define ATMSPROTO_LEN(ap) ((ap)->aar_spln)
164#define ATMOP(ap)   EXTRACT_16BITS(&(ap)->aar_op)
165#define ATMPRO(ap)  EXTRACT_16BITS(&(ap)->aar_pro)
166#define ATMTHRD_LEN(ap) ((ap)->aar_thtl & ATMARP_LEN_MASK)
167#define ATMTSLN(ap) ((ap)->aar_tstl & ATMARP_LEN_MASK)
168#define ATMTPROTO_LEN(ap) ((ap)->aar_tpln)
169#define aar_sha(ap)	((const u_char *)((ap)+1))
170#define aar_ssa(ap)	(aar_sha(ap) + ATMSHRD_LEN(ap))
171#define aar_spa(ap)	(aar_ssa(ap) + ATMSSLN(ap))
172#define aar_tha(ap)	(aar_spa(ap) + ATMSPROTO_LEN(ap))
173#define aar_tsa(ap)	(aar_tha(ap) + ATMTHRD_LEN(ap))
174#define aar_tpa(ap)	(aar_tsa(ap) + ATMTSLN(ap))
175};
176
177#define ATMSHA(ap) (aar_sha(ap))
178#define ATMSSA(ap) (aar_ssa(ap))
179#define ATMSPA(ap) (aar_spa(ap))
180#define ATMTHA(ap) (aar_tha(ap))
181#define ATMTSA(ap) (aar_tsa(ap))
182#define ATMTPA(ap) (aar_tpa(ap))
183
184static u_char ezero[6];
185
186static void
187atmarp_addr_print(netdissect_options *ndo,
188		  const u_char *ha, u_int ha_len, const u_char *srca,
189    u_int srca_len)
190{
191	if (ha_len == 0)
192		ND_PRINT((ndo, "<No address>"));
193	else {
194		ND_PRINT((ndo, "%s", linkaddr_string(ha, LINKADDR_ATM, ha_len)));
195		if (srca_len != 0)
196			ND_PRINT((ndo, ",%s",
197				  linkaddr_string(srca, LINKADDR_ATM, srca_len)));
198	}
199}
200
201static void
202atmarp_print(netdissect_options *ndo,
203	     const u_char *bp, u_int length, u_int caplen)
204{
205	const struct atmarp_pkthdr *ap;
206	u_short pro, hrd, op;
207
208	ap = (const struct atmarp_pkthdr *)bp;
209	ND_TCHECK(*ap);
210
211	hrd = ATMHRD(ap);
212	pro = ATMPRO(ap);
213	op = ATMOP(ap);
214
215	if (!ND_TTEST2(*aar_tpa(ap), ATMTPROTO_LEN(ap))) {
216		ND_PRINT((ndo, "[|ARP]"));
217		ND_DEFAULTPRINT((const u_char *)ap, length);
218		return;
219	}
220
221        if (!ndo->ndo_eflag) {
222            ND_PRINT((ndo, "ARP, "));
223        }
224
225	if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
226	    ATMSPROTO_LEN(ap) != 4 ||
227            ATMTPROTO_LEN(ap) != 4 ||
228            ndo->ndo_vflag) {
229                ND_PRINT((ndo, "%s, %s (len %u/%u)",
230                          tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
231                          tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
232                          ATMSPROTO_LEN(ap),
233                          ATMTPROTO_LEN(ap)));
234
235                /* don't know know about the address formats */
236                if (!ndo->ndo_vflag) {
237                    goto out;
238                }
239	}
240
241        /* print operation */
242        printf("%s%s ",
243               ndo->ndo_vflag ? ", " : "",
244               tok2str(arpop_values, "Unknown (%u)", op));
245
246	switch (op) {
247
248	case ARPOP_REQUEST:
249		ND_PRINT((ndo, "who-has %s", ipaddr_string(ATMTPA(ap))));
250		if (ATMTHRD_LEN(ap) != 0) {
251			ND_PRINT((ndo, " ("));
252			atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap),
253			    ATMTSA(ap), ATMTSLN(ap));
254			ND_PRINT((ndo, ")"));
255		}
256		ND_PRINT((ndo, "tell %s", ipaddr_string(ATMSPA(ap))));
257		break;
258
259	case ARPOP_REPLY:
260		ND_PRINT((ndo, "%s is-at ", ipaddr_string(ATMSPA(ap))));
261		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
262                                  ATMSSLN(ap));
263		break;
264
265	case ARPOP_INVREQUEST:
266		ND_PRINT((ndo, "who-is "));
267		atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap),
268		    ATMTSLN(ap));
269		ND_PRINT((ndo, " tell "));
270		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
271		    ATMSSLN(ap));
272		break;
273
274	case ARPOP_INVREPLY:
275		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
276		    ATMSSLN(ap));
277		ND_PRINT((ndo, "at %s", ipaddr_string(ATMSPA(ap))));
278		break;
279
280	case ARPOP_NAK:
281		ND_PRINT((ndo, "for %s", ipaddr_string(ATMSPA(ap))));
282		break;
283
284	default:
285		ND_DEFAULTPRINT((const u_char *)ap, caplen);
286		return;
287	}
288
289 out:
290        ND_PRINT((ndo, ", length %u", length));
291        return;
292
293trunc:
294	ND_PRINT((ndo, "[|ARP]"));
295}
296
297void
298arp_print(netdissect_options *ndo,
299	  const u_char *bp, u_int length, u_int caplen)
300{
301	const struct arp_pkthdr *ap;
302	u_short pro, hrd, op, linkaddr;
303
304	ap = (const struct arp_pkthdr *)bp;
305	ND_TCHECK(*ap);
306
307	hrd = HRD(ap);
308	pro = PRO(ap);
309	op = OP(ap);
310
311
312        /* if its ATM then call the ATM ARP printer
313           for Frame-relay ARP most of the fields
314           are similar to Ethernet so overload the Ethernet Printer
315           and set the linkaddr type for linkaddr_string() accordingly */
316
317        switch(hrd) {
318        case ARPHRD_ATM2225:
319            atmarp_print(ndo, bp, length, caplen);
320            return;
321        case ARPHRD_FRELAY:
322            linkaddr = LINKADDR_FRELAY;
323            break;
324        default:
325            linkaddr = LINKADDR_ETHER;
326            break;
327	}
328
329	if (!ND_TTEST2(*ar_tpa(ap), PROTO_LEN(ap))) {
330		ND_PRINT((ndo, "[|ARP]"));
331		ND_DEFAULTPRINT((const u_char *)ap, length);
332		return;
333	}
334
335        if (!ndo->ndo_eflag) {
336            ND_PRINT((ndo, "ARP, "));
337        }
338
339        /* print hardware type/len and proto type/len */
340        if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
341	    PROTO_LEN(ap) != 4 ||
342            HRD_LEN(ap) == 0 ||
343            ndo->ndo_vflag) {
344            ND_PRINT((ndo, "%s (len %u), %s (len %u)",
345                      tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
346                      HRD_LEN(ap),
347                      tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
348                      PROTO_LEN(ap)));
349
350            /* don't know know about the address formats */
351            if (!ndo->ndo_vflag) {
352                goto out;
353            }
354	}
355
356        /* print operation */
357        printf("%s%s ",
358               ndo->ndo_vflag ? ", " : "",
359               tok2str(arpop_values, "Unknown (%u)", op));
360
361	switch (op) {
362
363	case ARPOP_REQUEST:
364		ND_PRINT((ndo, "who-has %s", ipaddr_string(TPA(ap))));
365		if (memcmp((const char *)ezero, (const char *)THA(ap), HRD_LEN(ap)) != 0)
366			ND_PRINT((ndo, " (%s)",
367				  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap))));
368		ND_PRINT((ndo, " tell %s", ipaddr_string(SPA(ap))));
369		break;
370
371	case ARPOP_REPLY:
372		ND_PRINT((ndo, "%s is-at %s",
373                          ipaddr_string(SPA(ap)),
374                          linkaddr_string(SHA(ap), linkaddr, HRD_LEN(ap))));
375		break;
376
377	case ARPOP_REVREQUEST:
378		ND_PRINT((ndo, "who-is %s tell %s",
379			  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap)),
380			  linkaddr_string(SHA(ap), linkaddr, HRD_LEN(ap))));
381		break;
382
383	case ARPOP_REVREPLY:
384		ND_PRINT((ndo, "%s at %s",
385			  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap)),
386			  ipaddr_string(TPA(ap))));
387		break;
388
389	case ARPOP_INVREQUEST:
390		ND_PRINT((ndo, "who-is %s tell %s",
391			  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap)),
392			  linkaddr_string(SHA(ap), linkaddr, HRD_LEN(ap))));
393		break;
394
395	case ARPOP_INVREPLY:
396		ND_PRINT((ndo,"%s at %s",
397			  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap)),
398			  ipaddr_string(TPA(ap))));
399		break;
400
401	default:
402		ND_DEFAULTPRINT((const u_char *)ap, caplen);
403		return;
404	}
405
406 out:
407        ND_PRINT((ndo, ", length %u", length));
408
409	return;
410trunc:
411	ND_PRINT((ndo, "[|ARP]"));
412}
413
414/*
415 * Local Variables:
416 * c-style: bsd
417 * End:
418 */
419
420