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 /* \summary: Address Resolution Protocol (ARP) printer */
23
24 #ifdef HAVE_CONFIG_H
25 #include "config.h"
26 #endif
27
28 #include <netdissect-stdinc.h>
29
30 #include <string.h>
31
32 #include "netdissect.h"
33 #include "addrtoname.h"
34 #include "ether.h"
35 #include "ethertype.h"
36 #include "extract.h"
37
38 static const char tstr[] = "[|ARP]";
39
40 /*
41 * Address Resolution Protocol.
42 *
43 * See RFC 826 for protocol description. ARP packets are variable
44 * in size; the arphdr structure defines the fixed-length portion.
45 * Protocol type values are the same as those for 10 Mb/s Ethernet.
46 * It is followed by the variable-sized fields ar_sha, arp_spa,
47 * arp_tha and arp_tpa in that order, according to the lengths
48 * specified. Field names used correspond to RFC 826.
49 */
50 struct arp_pkthdr {
51 u_short ar_hrd; /* format of hardware address */
52 #define ARPHRD_ETHER 1 /* ethernet hardware format */
53 #define ARPHRD_IEEE802 6 /* token-ring hardware format */
54 #define ARPHRD_ARCNET 7 /* arcnet hardware format */
55 #define ARPHRD_FRELAY 15 /* frame relay hardware format */
56 #define ARPHRD_ATM2225 19 /* ATM (RFC 2225) */
57 #define ARPHRD_STRIP 23 /* Ricochet Starmode Radio hardware format */
58 #define ARPHRD_IEEE1394 24 /* IEEE 1394 (FireWire) hardware format */
59 u_short ar_pro; /* format of protocol address */
60 u_char ar_hln; /* length of hardware address */
61 u_char ar_pln; /* length of protocol address */
62 u_short ar_op; /* one of: */
63 #define ARPOP_REQUEST 1 /* request to resolve address */
64 #define ARPOP_REPLY 2 /* response to previous request */
65 #define ARPOP_REVREQUEST 3 /* request protocol address given hardware */
66 #define ARPOP_REVREPLY 4 /* response giving protocol address */
67 #define ARPOP_INVREQUEST 8 /* request to identify peer */
68 #define ARPOP_INVREPLY 9 /* response identifying peer */
69 #define ARPOP_NAK 10 /* NAK - only valif for ATM ARP */
70
71 /*
72 * The remaining fields are variable in size,
73 * according to the sizes above.
74 */
75 #ifdef COMMENT_ONLY
76 u_char ar_sha[]; /* sender hardware address */
77 u_char ar_spa[]; /* sender protocol address */
78 u_char ar_tha[]; /* target hardware address */
79 u_char ar_tpa[]; /* target protocol address */
80 #endif
81 #define ar_sha(ap) (((const u_char *)((ap)+1))+0)
82 #define ar_spa(ap) (((const u_char *)((ap)+1))+ (ap)->ar_hln)
83 #define ar_tha(ap) (((const u_char *)((ap)+1))+ (ap)->ar_hln+(ap)->ar_pln)
84 #define ar_tpa(ap) (((const u_char *)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln)
85 };
86
87 #define ARP_HDRLEN 8
88
89 #define HRD(ap) EXTRACT_16BITS(&(ap)->ar_hrd)
90 #define HRD_LEN(ap) ((ap)->ar_hln)
91 #define PROTO_LEN(ap) ((ap)->ar_pln)
92 #define OP(ap) EXTRACT_16BITS(&(ap)->ar_op)
93 #define PRO(ap) EXTRACT_16BITS(&(ap)->ar_pro)
94 #define SHA(ap) (ar_sha(ap))
95 #define SPA(ap) (ar_spa(ap))
96 #define THA(ap) (ar_tha(ap))
97 #define TPA(ap) (ar_tpa(ap))
98
99
100 static const struct tok arpop_values[] = {
101 { ARPOP_REQUEST, "Request" },
102 { ARPOP_REPLY, "Reply" },
103 { ARPOP_REVREQUEST, "Reverse Request" },
104 { ARPOP_REVREPLY, "Reverse Reply" },
105 { ARPOP_INVREQUEST, "Inverse Request" },
106 { ARPOP_INVREPLY, "Inverse Reply" },
107 { ARPOP_NAK, "NACK Reply" },
108 { 0, NULL }
109 };
110
111 static const struct tok arphrd_values[] = {
112 { ARPHRD_ETHER, "Ethernet" },
113 { ARPHRD_IEEE802, "TokenRing" },
114 { ARPHRD_ARCNET, "ArcNet" },
115 { ARPHRD_FRELAY, "FrameRelay" },
116 { ARPHRD_STRIP, "Strip" },
117 { ARPHRD_IEEE1394, "IEEE 1394" },
118 { ARPHRD_ATM2225, "ATM" },
119 { 0, NULL }
120 };
121
122 /*
123 * ATM Address Resolution Protocol.
124 *
125 * See RFC 2225 for protocol description. ATMARP packets are similar
126 * to ARP packets, except that there are no length fields for the
127 * protocol address - instead, there are type/length fields for
128 * the ATM number and subaddress - and the hardware addresses consist
129 * of an ATM number and an ATM subaddress.
130 */
131 struct atmarp_pkthdr {
132 u_short aar_hrd; /* format of hardware address */
133 u_short aar_pro; /* format of protocol address */
134 u_char aar_shtl; /* length of source ATM number */
135 u_char aar_sstl; /* length of source ATM subaddress */
136 #define ATMARP_IS_E164 0x40 /* bit in type/length for E.164 format */
137 #define ATMARP_LEN_MASK 0x3F /* length of {sub}address in type/length */
138 u_short aar_op; /* same as regular ARP */
139 u_char aar_spln; /* length of source protocol address */
140 u_char aar_thtl; /* length of target ATM number */
141 u_char aar_tstl; /* length of target ATM subaddress */
142 u_char aar_tpln; /* length of target protocol address */
143 /*
144 * The remaining fields are variable in size,
145 * according to the sizes above.
146 */
147 #ifdef COMMENT_ONLY
148 u_char aar_sha[]; /* source ATM number */
149 u_char aar_ssa[]; /* source ATM subaddress */
150 u_char aar_spa[]; /* sender protocol address */
151 u_char aar_tha[]; /* target ATM number */
152 u_char aar_tsa[]; /* target ATM subaddress */
153 u_char aar_tpa[]; /* target protocol address */
154 #endif
155
156 #define ATMHRD(ap) EXTRACT_16BITS(&(ap)->aar_hrd)
157 #define ATMSHRD_LEN(ap) ((ap)->aar_shtl & ATMARP_LEN_MASK)
158 #define ATMSSLN(ap) ((ap)->aar_sstl & ATMARP_LEN_MASK)
159 #define ATMSPROTO_LEN(ap) ((ap)->aar_spln)
160 #define ATMOP(ap) EXTRACT_16BITS(&(ap)->aar_op)
161 #define ATMPRO(ap) EXTRACT_16BITS(&(ap)->aar_pro)
162 #define ATMTHRD_LEN(ap) ((ap)->aar_thtl & ATMARP_LEN_MASK)
163 #define ATMTSLN(ap) ((ap)->aar_tstl & ATMARP_LEN_MASK)
164 #define ATMTPROTO_LEN(ap) ((ap)->aar_tpln)
165 #define aar_sha(ap) ((const u_char *)((ap)+1))
166 #define aar_ssa(ap) (aar_sha(ap) + ATMSHRD_LEN(ap))
167 #define aar_spa(ap) (aar_ssa(ap) + ATMSSLN(ap))
168 #define aar_tha(ap) (aar_spa(ap) + ATMSPROTO_LEN(ap))
169 #define aar_tsa(ap) (aar_tha(ap) + ATMTHRD_LEN(ap))
170 #define aar_tpa(ap) (aar_tsa(ap) + ATMTSLN(ap))
171 };
172
173 #define ATMSHA(ap) (aar_sha(ap))
174 #define ATMSSA(ap) (aar_ssa(ap))
175 #define ATMSPA(ap) (aar_spa(ap))
176 #define ATMTHA(ap) (aar_tha(ap))
177 #define ATMTSA(ap) (aar_tsa(ap))
178 #define ATMTPA(ap) (aar_tpa(ap))
179
180 static int
isnonzero(const u_char * a,size_t len)181 isnonzero(const u_char *a, size_t len)
182 {
183 while (len > 0) {
184 if (*a != 0)
185 return (1);
186 a++;
187 len--;
188 }
189 return (0);
190 }
191
192 static void
atmarp_addr_print(netdissect_options * ndo,const u_char * ha,u_int ha_len,const u_char * srca,u_int srca_len)193 atmarp_addr_print(netdissect_options *ndo,
194 const u_char *ha, u_int ha_len, const u_char *srca,
195 u_int srca_len)
196 {
197 if (ha_len == 0)
198 ND_PRINT((ndo, "<No address>"));
199 else {
200 ND_PRINT((ndo, "%s", linkaddr_string(ndo, ha, LINKADDR_ATM, ha_len)));
201 if (srca_len != 0)
202 ND_PRINT((ndo, ",%s",
203 linkaddr_string(ndo, srca, LINKADDR_ATM, srca_len)));
204 }
205 }
206
207 static void
atmarp_print(netdissect_options * ndo,const u_char * bp,u_int length,u_int caplen)208 atmarp_print(netdissect_options *ndo,
209 const u_char *bp, u_int length, u_int caplen)
210 {
211 const struct atmarp_pkthdr *ap;
212 u_short pro, hrd, op;
213
214 ap = (const struct atmarp_pkthdr *)bp;
215 ND_TCHECK(*ap);
216
217 hrd = ATMHRD(ap);
218 pro = ATMPRO(ap);
219 op = ATMOP(ap);
220
221 if (!ND_TTEST2(*aar_tpa(ap), ATMTPROTO_LEN(ap))) {
222 ND_PRINT((ndo, "%s", tstr));
223 ND_DEFAULTPRINT((const u_char *)ap, length);
224 return;
225 }
226
227 if (!ndo->ndo_eflag) {
228 ND_PRINT((ndo, "ARP, "));
229 }
230
231 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
232 ATMSPROTO_LEN(ap) != 4 ||
233 ATMTPROTO_LEN(ap) != 4 ||
234 ndo->ndo_vflag) {
235 ND_PRINT((ndo, "%s, %s (len %u/%u)",
236 tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
237 tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
238 ATMSPROTO_LEN(ap),
239 ATMTPROTO_LEN(ap)));
240
241 /* don't know know about the address formats */
242 if (!ndo->ndo_vflag) {
243 goto out;
244 }
245 }
246
247 /* print operation */
248 ND_PRINT((ndo, "%s%s ",
249 ndo->ndo_vflag ? ", " : "",
250 tok2str(arpop_values, "Unknown (%u)", op)));
251
252 switch (op) {
253
254 case ARPOP_REQUEST:
255 ND_PRINT((ndo, "who-has %s", ipaddr_string(ndo, ATMTPA(ap))));
256 if (ATMTHRD_LEN(ap) != 0) {
257 ND_PRINT((ndo, " ("));
258 atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap),
259 ATMTSA(ap), ATMTSLN(ap));
260 ND_PRINT((ndo, ")"));
261 }
262 ND_PRINT((ndo, "tell %s", ipaddr_string(ndo, ATMSPA(ap))));
263 break;
264
265 case ARPOP_REPLY:
266 ND_PRINT((ndo, "%s is-at ", ipaddr_string(ndo, ATMSPA(ap))));
267 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
268 ATMSSLN(ap));
269 break;
270
271 case ARPOP_INVREQUEST:
272 ND_PRINT((ndo, "who-is "));
273 atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap),
274 ATMTSLN(ap));
275 ND_PRINT((ndo, " tell "));
276 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
277 ATMSSLN(ap));
278 break;
279
280 case ARPOP_INVREPLY:
281 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
282 ATMSSLN(ap));
283 ND_PRINT((ndo, "at %s", ipaddr_string(ndo, ATMSPA(ap))));
284 break;
285
286 case ARPOP_NAK:
287 ND_PRINT((ndo, "for %s", ipaddr_string(ndo, ATMSPA(ap))));
288 break;
289
290 default:
291 ND_DEFAULTPRINT((const u_char *)ap, caplen);
292 return;
293 }
294
295 out:
296 ND_PRINT((ndo, ", length %u", length));
297 return;
298
299 trunc:
300 ND_PRINT((ndo, "%s", tstr));
301 }
302
303 void
arp_print(netdissect_options * ndo,const u_char * bp,u_int length,u_int caplen)304 arp_print(netdissect_options *ndo,
305 const u_char *bp, u_int length, u_int caplen)
306 {
307 const struct arp_pkthdr *ap;
308 u_short pro, hrd, op, linkaddr;
309
310 ap = (const struct arp_pkthdr *)bp;
311 ND_TCHECK(*ap);
312
313 hrd = HRD(ap);
314 pro = PRO(ap);
315 op = OP(ap);
316
317
318 /* if its ATM then call the ATM ARP printer
319 for Frame-relay ARP most of the fields
320 are similar to Ethernet so overload the Ethernet Printer
321 and set the linkaddr type for linkaddr_string(ndo, ) accordingly */
322
323 switch(hrd) {
324 case ARPHRD_ATM2225:
325 atmarp_print(ndo, bp, length, caplen);
326 return;
327 case ARPHRD_FRELAY:
328 linkaddr = LINKADDR_FRELAY;
329 break;
330 default:
331 linkaddr = LINKADDR_ETHER;
332 break;
333 }
334
335 if (!ND_TTEST2(*ar_tpa(ap), PROTO_LEN(ap))) {
336 ND_PRINT((ndo, "%s", tstr));
337 ND_DEFAULTPRINT((const u_char *)ap, length);
338 return;
339 }
340
341 if (!ndo->ndo_eflag) {
342 ND_PRINT((ndo, "ARP, "));
343 }
344
345 /* print hardware type/len and proto type/len */
346 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
347 PROTO_LEN(ap) != 4 ||
348 HRD_LEN(ap) == 0 ||
349 ndo->ndo_vflag) {
350 ND_PRINT((ndo, "%s (len %u), %s (len %u)",
351 tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
352 HRD_LEN(ap),
353 tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
354 PROTO_LEN(ap)));
355
356 /* don't know know about the address formats */
357 if (!ndo->ndo_vflag) {
358 goto out;
359 }
360 }
361
362 /* print operation */
363 ND_PRINT((ndo, "%s%s ",
364 ndo->ndo_vflag ? ", " : "",
365 tok2str(arpop_values, "Unknown (%u)", op)));
366
367 switch (op) {
368
369 case ARPOP_REQUEST:
370 ND_PRINT((ndo, "who-has %s", ipaddr_string(ndo, TPA(ap))));
371 if (isnonzero((const u_char *)THA(ap), HRD_LEN(ap)))
372 ND_PRINT((ndo, " (%s)",
373 linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap))));
374 ND_PRINT((ndo, " tell %s", ipaddr_string(ndo, SPA(ap))));
375 break;
376
377 case ARPOP_REPLY:
378 ND_PRINT((ndo, "%s is-at %s",
379 ipaddr_string(ndo, SPA(ap)),
380 linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap))));
381 break;
382
383 case ARPOP_REVREQUEST:
384 ND_PRINT((ndo, "who-is %s tell %s",
385 linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)),
386 linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap))));
387 break;
388
389 case ARPOP_REVREPLY:
390 ND_PRINT((ndo, "%s at %s",
391 linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)),
392 ipaddr_string(ndo, TPA(ap))));
393 break;
394
395 case ARPOP_INVREQUEST:
396 ND_PRINT((ndo, "who-is %s tell %s",
397 linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)),
398 linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap))));
399 break;
400
401 case ARPOP_INVREPLY:
402 ND_PRINT((ndo,"%s at %s",
403 linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)),
404 ipaddr_string(ndo, SPA(ap))));
405 break;
406
407 default:
408 ND_DEFAULTPRINT((const u_char *)ap, caplen);
409 return;
410 }
411
412 out:
413 ND_PRINT((ndo, ", length %u", length));
414
415 return;
416 trunc:
417 ND_PRINT((ndo, "%s", tstr));
418 }
419
420 /*
421 * Local Variables:
422 * c-style: bsd
423 * End:
424 */
425
426