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 1.66 2006-03-03 22:53:21 hannes 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_ATM2225  19      /* ATM (RFC 2225) */
59#define ARPHRD_STRIP    23      /* Ricochet Starmode Radio hardware format */
60#define ARPHRD_IEEE1394 24      /* IEEE 1394 (FireWire) hardware format */
61        u_short ar_pro;         /* format of protocol address */
62        u_char  ar_hln;         /* length of hardware address */
63        u_char  ar_pln;         /* length of protocol address */
64        u_short ar_op;          /* one of: */
65#define ARPOP_REQUEST   1       /* request to resolve address */
66#define ARPOP_REPLY     2       /* response to previous request */
67#define ARPOP_REVREQUEST 3      /* request protocol address given hardware */
68#define ARPOP_REVREPLY  4       /* response giving protocol address */
69#define ARPOP_INVREQUEST 8      /* request to identify peer */
70#define ARPOP_INVREPLY  9       /* response identifying peer */
71#define ARPOP_NAK       10      /* NAK - only valif for ATM ARP */
72
73/*
74 * The remaining fields are variable in size,
75 * according to the sizes above.
76 */
77#ifdef COMMENT_ONLY
78	u_char	ar_sha[];	/* sender hardware address */
79	u_char	ar_spa[];	/* sender protocol address */
80	u_char	ar_tha[];	/* target hardware address */
81	u_char	ar_tpa[];	/* target protocol address */
82#endif
83#define ar_sha(ap)	(((const u_char *)((ap)+1))+0)
84#define ar_spa(ap)	(((const u_char *)((ap)+1))+  (ap)->ar_hln)
85#define ar_tha(ap)	(((const u_char *)((ap)+1))+  (ap)->ar_hln+(ap)->ar_pln)
86#define ar_tpa(ap)	(((const u_char *)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln)
87};
88
89#define ARP_HDRLEN	8
90
91#define HRD(ap) EXTRACT_16BITS(&(ap)->ar_hrd)
92#define HRD_LEN(ap) ((ap)->ar_hln)
93#define PROTO_LEN(ap) ((ap)->ar_pln)
94#define OP(ap)  EXTRACT_16BITS(&(ap)->ar_op)
95#define PRO(ap) EXTRACT_16BITS(&(ap)->ar_pro)
96#define SHA(ap) (ar_sha(ap))
97#define SPA(ap) (ar_spa(ap))
98#define THA(ap) (ar_tha(ap))
99#define TPA(ap) (ar_tpa(ap))
100
101
102static const struct tok arpop_values[] = {
103    { ARPOP_REQUEST, "Request" },
104    { ARPOP_REPLY, "Reply" },
105    { ARPOP_REVREQUEST, "Reverse Request" },
106    { ARPOP_REVREPLY, "Reverse Reply" },
107    { ARPOP_INVREQUEST, "Inverse Request" },
108    { ARPOP_INVREPLY, "Inverse Reply" },
109    { ARPOP_NAK, "NACK Reply" },
110    { 0, NULL }
111};
112
113static const struct tok arphrd_values[] = {
114    { ARPHRD_ETHER, "Ethernet" },
115    { ARPHRD_IEEE802, "TokenRing" },
116    { ARPHRD_ARCNET, "ArcNet" },
117    { ARPHRD_FRELAY, "FrameRelay" },
118    { ARPHRD_STRIP, "Strip" },
119    { ARPHRD_IEEE1394, "IEEE 1394" },
120    { ARPHRD_ATM2225, "ATM" },
121    { 0, NULL }
122};
123
124/*
125 * ATM Address Resolution Protocol.
126 *
127 * See RFC 2225 for protocol description.  ATMARP packets are similar
128 * to ARP packets, except that there are no length fields for the
129 * protocol address - instead, there are type/length fields for
130 * the ATM number and subaddress - and the hardware addresses consist
131 * of an ATM number and an ATM subaddress.
132 */
133struct  atmarp_pkthdr {
134        u_short aar_hrd;        /* format of hardware address */
135        u_short aar_pro;        /* format of protocol address */
136        u_char  aar_shtl;       /* length of source ATM number */
137        u_char  aar_sstl;       /* length of source ATM subaddress */
138#define ATMARP_IS_E164  0x40    /* bit in type/length for E.164 format */
139#define ATMARP_LEN_MASK 0x3F    /* length of {sub}address in type/length */
140        u_short aar_op;         /* same as regular ARP */
141        u_char  aar_spln;       /* length of source protocol address */
142        u_char  aar_thtl;       /* length of target ATM number */
143        u_char  aar_tstl;       /* length of target ATM subaddress */
144        u_char  aar_tpln;       /* length of target protocol address */
145/*
146 * The remaining fields are variable in size,
147 * according to the sizes above.
148 */
149#ifdef COMMENT_ONLY
150	u_char	aar_sha[];	/* source ATM number */
151	u_char	aar_ssa[];	/* source ATM subaddress */
152	u_char	aar_spa[];	/* sender protocol address */
153	u_char	aar_tha[];	/* target ATM number */
154	u_char	aar_tsa[];	/* target ATM subaddress */
155	u_char	aar_tpa[];	/* target protocol address */
156#endif
157
158#define ATMHRD(ap)  EXTRACT_16BITS(&(ap)->aar_hrd)
159#define ATMSHRD_LEN(ap) ((ap)->aar_shtl & ATMARP_LEN_MASK)
160#define ATMSSLN(ap) ((ap)->aar_sstl & ATMARP_LEN_MASK)
161#define ATMSPROTO_LEN(ap) ((ap)->aar_spln)
162#define ATMOP(ap)   EXTRACT_16BITS(&(ap)->aar_op)
163#define ATMPRO(ap)  EXTRACT_16BITS(&(ap)->aar_pro)
164#define ATMTHRD_LEN(ap) ((ap)->aar_thtl & ATMARP_LEN_MASK)
165#define ATMTSLN(ap) ((ap)->aar_tstl & ATMARP_LEN_MASK)
166#define ATMTPROTO_LEN(ap) ((ap)->aar_tpln)
167#define aar_sha(ap)	((const u_char *)((ap)+1))
168#define aar_ssa(ap)	(aar_sha(ap) + ATMSHRD_LEN(ap))
169#define aar_spa(ap)	(aar_ssa(ap) + ATMSSLN(ap))
170#define aar_tha(ap)	(aar_spa(ap) + ATMSPROTO_LEN(ap))
171#define aar_tsa(ap)	(aar_tha(ap) + ATMTHRD_LEN(ap))
172#define aar_tpa(ap)	(aar_tsa(ap) + ATMTSLN(ap))
173};
174
175#define ATMSHA(ap) (aar_sha(ap))
176#define ATMSSA(ap) (aar_ssa(ap))
177#define ATMSPA(ap) (aar_spa(ap))
178#define ATMTHA(ap) (aar_tha(ap))
179#define ATMTSA(ap) (aar_tsa(ap))
180#define ATMTPA(ap) (aar_tpa(ap))
181
182static u_char ezero[6];
183
184static void
185atmarp_addr_print(netdissect_options *ndo,
186		  const u_char *ha, u_int ha_len, const u_char *srca,
187    u_int srca_len)
188{
189	if (ha_len == 0)
190		ND_PRINT((ndo, "<No address>"));
191	else {
192		ND_PRINT((ndo, "%s", linkaddr_string(ha, LINKADDR_ATM, ha_len)));
193		if (srca_len != 0)
194			ND_PRINT((ndo, ",%s",
195				  linkaddr_string(srca, LINKADDR_ATM, srca_len)));
196	}
197}
198
199static void
200atmarp_print(netdissect_options *ndo,
201	     const u_char *bp, u_int length, u_int caplen)
202{
203	const struct atmarp_pkthdr *ap;
204	u_short pro, hrd, op;
205
206	ap = (const struct atmarp_pkthdr *)bp;
207	ND_TCHECK(*ap);
208
209	hrd = ATMHRD(ap);
210	pro = ATMPRO(ap);
211	op = ATMOP(ap);
212
213	if (!ND_TTEST2(*aar_tpa(ap), ATMTPROTO_LEN(ap))) {
214		ND_PRINT((ndo, "[|ARP]"));
215		ND_DEFAULTPRINT((const u_char *)ap, length);
216		return;
217	}
218
219        if (!ndo->ndo_eflag) {
220            ND_PRINT((ndo, "ARP, "));
221        }
222
223	if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
224	    ATMSPROTO_LEN(ap) != 4 ||
225            ATMTPROTO_LEN(ap) != 4 ||
226            ndo->ndo_vflag) {
227                ND_PRINT((ndo, "%s, %s (len %u/%u)",
228                          tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
229                          tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
230                          ATMSPROTO_LEN(ap),
231                          ATMTPROTO_LEN(ap)));
232
233                /* don't know know about the address formats */
234                if (!ndo->ndo_vflag) {
235                    goto out;
236                }
237	}
238
239        /* print operation */
240        printf("%s%s ",
241               ndo->ndo_vflag ? ", " : "",
242               tok2str(arpop_values, "Unknown (%u)", op));
243
244	switch (op) {
245
246	case ARPOP_REQUEST:
247		ND_PRINT((ndo, "who-has %s", ipaddr_string(ATMTPA(ap))));
248		if (ATMTHRD_LEN(ap) != 0) {
249			ND_PRINT((ndo, " ("));
250			atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap),
251			    ATMTSA(ap), ATMTSLN(ap));
252			ND_PRINT((ndo, ")"));
253		}
254		ND_PRINT((ndo, "tell %s", ipaddr_string(ATMSPA(ap))));
255		break;
256
257	case ARPOP_REPLY:
258		ND_PRINT((ndo, "%s is-at ", ipaddr_string(ATMSPA(ap))));
259		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
260                                  ATMSSLN(ap));
261		break;
262
263	case ARPOP_INVREQUEST:
264		ND_PRINT((ndo, "who-is "));
265		atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap),
266		    ATMTSLN(ap));
267		ND_PRINT((ndo, " tell "));
268		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
269		    ATMSSLN(ap));
270		break;
271
272	case ARPOP_INVREPLY:
273		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
274		    ATMSSLN(ap));
275		ND_PRINT((ndo, "at %s", ipaddr_string(ATMSPA(ap))));
276		break;
277
278	case ARPOP_NAK:
279		ND_PRINT((ndo, "for %s", ipaddr_string(ATMSPA(ap))));
280		break;
281
282	default:
283		ND_DEFAULTPRINT((const u_char *)ap, caplen);
284		return;
285	}
286
287 out:
288        ND_PRINT((ndo, ", length %u", length));
289        return;
290
291trunc:
292	ND_PRINT((ndo, "[|ARP]"));
293}
294
295void
296arp_print(netdissect_options *ndo,
297	  const u_char *bp, u_int length, u_int caplen)
298{
299	const struct arp_pkthdr *ap;
300	u_short pro, hrd, op, linkaddr;
301
302	ap = (const struct arp_pkthdr *)bp;
303	ND_TCHECK(*ap);
304
305	hrd = HRD(ap);
306	pro = PRO(ap);
307	op = OP(ap);
308
309
310        /* if its ATM then call the ATM ARP printer
311           for Frame-relay ARP most of the fields
312           are similar to Ethernet so overload the Ethernet Printer
313           and set the linkaddr type for linkaddr_string() accordingly */
314
315        switch(hrd) {
316        case ARPHRD_ATM2225:
317            atmarp_print(ndo, bp, length, caplen);
318            return;
319        case ARPHRD_FRELAY:
320            linkaddr = LINKADDR_FRELAY;
321            break;
322        default:
323            linkaddr = LINKADDR_ETHER;
324            break;
325	}
326
327	if (!ND_TTEST2(*ar_tpa(ap), PROTO_LEN(ap))) {
328		ND_PRINT((ndo, "[|ARP]"));
329		ND_DEFAULTPRINT((const u_char *)ap, length);
330		return;
331	}
332
333        if (!ndo->ndo_eflag) {
334            ND_PRINT((ndo, "ARP, "));
335        }
336
337        /* print hardware type/len and proto type/len */
338        if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
339	    PROTO_LEN(ap) != 4 ||
340            HRD_LEN(ap) == 0 ||
341            ndo->ndo_vflag) {
342            ND_PRINT((ndo, "%s (len %u), %s (len %u)",
343                      tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
344                      HRD_LEN(ap),
345                      tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
346                      PROTO_LEN(ap)));
347
348            /* don't know know about the address formats */
349            if (!ndo->ndo_vflag) {
350                goto out;
351            }
352	}
353
354        /* print operation */
355        printf("%s%s ",
356               ndo->ndo_vflag ? ", " : "",
357               tok2str(arpop_values, "Unknown (%u)", op));
358
359	switch (op) {
360
361	case ARPOP_REQUEST:
362		ND_PRINT((ndo, "who-has %s", ipaddr_string(TPA(ap))));
363		if (memcmp((const char *)ezero, (const char *)THA(ap), HRD_LEN(ap)) != 0)
364			ND_PRINT((ndo, " (%s)",
365				  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap))));
366		ND_PRINT((ndo, " tell %s", ipaddr_string(SPA(ap))));
367		break;
368
369	case ARPOP_REPLY:
370		ND_PRINT((ndo, "%s is-at %s",
371                          ipaddr_string(SPA(ap)),
372                          linkaddr_string(SHA(ap), linkaddr, HRD_LEN(ap))));
373		break;
374
375	case ARPOP_REVREQUEST:
376		ND_PRINT((ndo, "who-is %s tell %s",
377			  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap)),
378			  linkaddr_string(SHA(ap), linkaddr, HRD_LEN(ap))));
379		break;
380
381	case ARPOP_REVREPLY:
382		ND_PRINT((ndo, "%s at %s",
383			  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap)),
384			  ipaddr_string(TPA(ap))));
385		break;
386
387	case ARPOP_INVREQUEST:
388		ND_PRINT((ndo, "who-is %s tell %s",
389			  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap)),
390			  linkaddr_string(SHA(ap), linkaddr, HRD_LEN(ap))));
391		break;
392
393	case ARPOP_INVREPLY:
394		ND_PRINT((ndo,"%s at %s",
395			  linkaddr_string(THA(ap), linkaddr, HRD_LEN(ap)),
396			  ipaddr_string(TPA(ap))));
397		break;
398
399	default:
400		ND_DEFAULTPRINT((const u_char *)ap, caplen);
401		return;
402	}
403
404 out:
405        ND_PRINT((ndo, ", length %u", length));
406
407	return;
408trunc:
409	ND_PRINT((ndo, "[|ARP]"));
410}
411
412/*
413 * Local Variables:
414 * c-style: bsd
415 * End:
416 */
417
418