xref: /netbsd-src/external/bsd/tcpdump/dist/print-arp.c (revision 26ba0b503b498a5194a71ac319838b7f5497f3fe)
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 #include <sys/cdefs.h>
23 #ifndef lint
24 __RCSID("$NetBSD: print-arp.c,v 1.11 2024/09/02 16:15:30 christos Exp $");
25 #endif
26 
27 /* \summary: Address Resolution Protocol (ARP) printer */
28 
29 #include <config.h>
30 
31 #include "netdissect-stdinc.h"
32 
33 #define ND_LONGJMP_FROM_TCHECK
34 #include "netdissect.h"
35 #include "addrtoname.h"
36 #include "ethertype.h"
37 #include "extract.h"
38 
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         nd_uint16_t 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 #define ARPHRD_INFINIBAND 32    /* InfiniBand RFC 4391 */
60         nd_uint16_t ar_pro;     /* format of protocol address */
61         nd_uint8_t  ar_hln;     /* length of hardware address */
62         nd_uint8_t  ar_pln;     /* length of protocol address */
63         nd_uint16_t 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 #define ARPOP_NAK       10      /* NAK - only valid for ATM ARP */
71 
72 /*
73  * The remaining fields are variable in size,
74  * according to the sizes above.
75  */
76 #ifdef COMMENT_ONLY
77 	nd_byte		ar_sha[];	/* sender hardware address */
78 	nd_byte		ar_spa[];	/* sender protocol address */
79 	nd_byte		ar_tha[];	/* target hardware address */
80 	nd_byte		ar_tpa[];	/* target protocol address */
81 #endif
82 #define ar_sha(ap)	(((const u_char *)((ap)+1))+  0)
83 #define ar_spa(ap)	(((const u_char *)((ap)+1))+  GET_U_1((ap)->ar_hln))
84 #define ar_tha(ap)	(((const u_char *)((ap)+1))+  GET_U_1((ap)->ar_hln)+GET_U_1((ap)->ar_pln))
85 #define ar_tpa(ap)	(((const u_char *)((ap)+1))+2*GET_U_1((ap)->ar_hln)+GET_U_1((ap)->ar_pln))
86 };
87 
88 #define ARP_HDRLEN	8
89 
90 #define HRD(ap) GET_BE_U_2((ap)->ar_hrd)
91 #define HRD_LEN(ap) GET_U_1((ap)->ar_hln)
92 #define PROTO_LEN(ap) GET_U_1((ap)->ar_pln)
93 #define OP(ap)  GET_BE_U_2((ap)->ar_op)
94 #define PRO(ap) GET_BE_U_2((ap)->ar_pro)
95 #define SHA(ap) (ar_sha(ap))
96 #define SPA(ap) (ar_spa(ap))
97 #define THA(ap) (ar_tha(ap))
98 #define TPA(ap) (ar_tpa(ap))
99 
100 
101 static const struct tok arpop_values[] = {
102     { ARPOP_REQUEST, "Request" },
103     { ARPOP_REPLY, "Reply" },
104     { ARPOP_REVREQUEST, "Reverse Request" },
105     { ARPOP_REVREPLY, "Reverse Reply" },
106     { ARPOP_INVREQUEST, "Inverse Request" },
107     { ARPOP_INVREPLY, "Inverse Reply" },
108     { ARPOP_NAK, "NACK Reply" },
109     { 0, NULL }
110 };
111 
112 static const struct tok arphrd_values[] = {
113     { ARPHRD_ETHER, "Ethernet" },
114     { ARPHRD_IEEE802, "TokenRing" },
115     { ARPHRD_ARCNET, "ArcNet" },
116     { ARPHRD_FRELAY, "FrameRelay" },
117     { ARPHRD_STRIP, "Strip" },
118     { ARPHRD_IEEE1394, "IEEE 1394" },
119     { ARPHRD_ATM2225, "ATM" },
120     { ARPHRD_INFINIBAND, "InfiniBand" },
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  */
133 struct  atmarp_pkthdr {
134         nd_uint16_t aar_hrd;    /* format of hardware address */
135         nd_uint16_t aar_pro;    /* format of protocol address */
136         nd_uint8_t  aar_shtl;   /* length of source ATM number */
137         nd_uint8_t  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         nd_uint16_t aar_op;     /* same as regular ARP */
141         nd_uint8_t  aar_spln;   /* length of source protocol address */
142         nd_uint8_t  aar_thtl;   /* length of target ATM number */
143         nd_uint8_t  aar_tstl;   /* length of target ATM subaddress */
144         nd_uint8_t  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 	nd_byte		aar_sha[];	/* source ATM number */
151 	nd_byte		aar_ssa[];	/* source ATM subaddress */
152 	nd_byte		aar_spa[];	/* sender protocol address */
153 	nd_byte		aar_tha[];	/* target ATM number */
154 	nd_byte		aar_tsa[];	/* target ATM subaddress */
155 	nd_byte		aar_tpa[];	/* target protocol address */
156 #endif
157 
158 #define ATMHRD(ap)  GET_BE_U_2((ap)->aar_hrd)
159 #define ATMSHRD_LEN(ap) (GET_U_1((ap)->aar_shtl) & ATMARP_LEN_MASK)
160 #define ATMSSLN(ap) (GET_U_1((ap)->aar_sstl) & ATMARP_LEN_MASK)
161 #define ATMSPROTO_LEN(ap) GET_U_1((ap)->aar_spln)
162 #define ATMOP(ap)   GET_BE_U_2((ap)->aar_op)
163 #define ATMPRO(ap)  GET_BE_U_2((ap)->aar_pro)
164 #define ATMTHRD_LEN(ap) (GET_U_1((ap)->aar_thtl) & ATMARP_LEN_MASK)
165 #define ATMTSLN(ap) (GET_U_1((ap)->aar_tstl) & ATMARP_LEN_MASK)
166 #define ATMTPROTO_LEN(ap) GET_U_1((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 
182 static int
183 isnonzero(netdissect_options *ndo, const u_char *a, size_t len)
184 {
185 	while (len > 0) {
186 		if (GET_U_1(a) != 0)
187 			return (1);
188 		a++;
189 		len--;
190 	}
191 	return (0);
192 }
193 
194 static void
195 tpaddr_print_ip(netdissect_options *ndo,
196 	        const struct arp_pkthdr *ap, u_short pro)
197 {
198 	if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
199 		ND_PRINT("<wrong proto type>");
200 	else if (PROTO_LEN(ap) != 4)
201 		ND_PRINT("<wrong len>");
202 	else
203 		ND_PRINT("%s", GET_IPADDR_STRING(TPA(ap)));
204 }
205 
206 static void
207 spaddr_print_ip(netdissect_options *ndo,
208 	        const struct arp_pkthdr *ap, u_short pro)
209 {
210 	if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
211 		ND_PRINT("<wrong proto type>");
212 	else if (PROTO_LEN(ap) != 4)
213 		ND_PRINT("<wrong len>");
214 	else
215 		ND_PRINT("%s", GET_IPADDR_STRING(SPA(ap)));
216 }
217 
218 static void
219 atmarp_addr_print(netdissect_options *ndo,
220 		  const u_char *ha, u_int ha_len, const u_char *srca,
221     u_int srca_len)
222 {
223 	if (ha_len == 0)
224 		ND_PRINT("<No address>");
225 	else {
226 		ND_PRINT("%s", GET_LINKADDR_STRING(ha, LINKADDR_ATM, ha_len));
227 		if (srca_len != 0)
228 			ND_PRINT(",%s",
229 				  GET_LINKADDR_STRING(srca, LINKADDR_ATM, srca_len));
230 	}
231 }
232 
233 static void
234 atmarp_tpaddr_print(netdissect_options *ndo,
235 		    const struct atmarp_pkthdr *ap, u_short pro)
236 {
237 	if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
238 		ND_PRINT("<wrong proto type>");
239 	else if (ATMTPROTO_LEN(ap) != 4)
240 		ND_PRINT("<wrong tplen>");
241 	else
242 		ND_PRINT("%s", GET_IPADDR_STRING(ATMTPA(ap)));
243 }
244 
245 static void
246 atmarp_spaddr_print(netdissect_options *ndo,
247 		    const struct atmarp_pkthdr *ap, u_short pro)
248 {
249 	if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
250 		ND_PRINT("<wrong proto type>");
251 	else if (ATMSPROTO_LEN(ap) != 4)
252 		ND_PRINT("<wrong splen>");
253 	else
254 		ND_PRINT("%s", GET_IPADDR_STRING(ATMSPA(ap)));
255 }
256 
257 static void
258 atmarp_print(netdissect_options *ndo,
259 	     const u_char *bp, u_int length, u_int caplen)
260 {
261 	const struct atmarp_pkthdr *ap;
262 	u_short pro, hrd, op;
263 
264 	ap = (const struct atmarp_pkthdr *)bp;
265 	ND_TCHECK_SIZE(ap);
266 
267 	hrd = ATMHRD(ap);
268 	pro = ATMPRO(ap);
269 	op = ATMOP(ap);
270 
271 	ND_TCHECK_LEN(ATMTPA(ap), ATMTPROTO_LEN(ap));
272 
273         if (!ndo->ndo_eflag) {
274             ND_PRINT("ARP, ");
275         }
276 
277 	if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
278 	    ATMSPROTO_LEN(ap) != 4 ||
279             ATMTPROTO_LEN(ap) != 4 ||
280             ndo->ndo_vflag) {
281                 ND_PRINT("%s, %s (len %u/%u)",
282                           tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
283                           tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
284                           ATMSPROTO_LEN(ap),
285                           ATMTPROTO_LEN(ap));
286 
287                 /* don't know about the address formats */
288                 if (!ndo->ndo_vflag) {
289                     goto out;
290                 }
291 	}
292 
293         /* print operation */
294         ND_PRINT("%s%s ",
295                ndo->ndo_vflag ? ", " : "",
296                tok2str(arpop_values, "Unknown (%u)", op));
297 
298 	switch (op) {
299 
300 	case ARPOP_REQUEST:
301 		ND_PRINT("who-has ");
302 		atmarp_tpaddr_print(ndo, ap, pro);
303 		if (ATMTHRD_LEN(ap) != 0) {
304 			ND_PRINT(" (");
305 			atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap),
306 			    ATMTSA(ap), ATMTSLN(ap));
307 			ND_PRINT(")");
308 		}
309 		ND_PRINT(" tell ");
310 		atmarp_spaddr_print(ndo, ap, pro);
311 		break;
312 
313 	case ARPOP_REPLY:
314 		atmarp_spaddr_print(ndo, ap, pro);
315 		ND_PRINT(" is-at ");
316 		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
317                                   ATMSSLN(ap));
318 		break;
319 
320 	case ARPOP_INVREQUEST:
321 		ND_PRINT("who-is ");
322 		atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap),
323 		    ATMTSLN(ap));
324 		ND_PRINT(" tell ");
325 		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
326 		    ATMSSLN(ap));
327 		break;
328 
329 	case ARPOP_INVREPLY:
330 		atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
331 		    ATMSSLN(ap));
332 		ND_PRINT("at ");
333 		atmarp_spaddr_print(ndo, ap, pro);
334 		break;
335 
336 	case ARPOP_NAK:
337 		ND_PRINT("for ");
338 		atmarp_spaddr_print(ndo, ap, pro);
339 		break;
340 
341 	default:
342 		ND_DEFAULTPRINT((const u_char *)ap, caplen);
343 		return;
344 	}
345 
346  out:
347         ND_PRINT(", length %u", length);
348 }
349 
350 void
351 arp_print(netdissect_options *ndo,
352 	  const u_char *bp, u_int length, u_int caplen)
353 {
354 	const struct arp_pkthdr *ap;
355 	u_short pro, hrd, op, linkaddr;
356 
357 	ndo->ndo_protocol = "arp";
358 	ap = (const struct arp_pkthdr *)bp;
359 	ND_TCHECK_SIZE(ap);
360 
361 	hrd = HRD(ap);
362 	pro = PRO(ap);
363 	op = OP(ap);
364 
365 
366         /* if its ATM then call the ATM ARP printer
367            for Frame-relay ARP most of the fields
368            are similar to Ethernet so overload the Ethernet Printer
369            and set the linkaddr type for GET_LINKADDR_STRING() accordingly */
370 
371         switch(hrd) {
372         case ARPHRD_ATM2225:
373             atmarp_print(ndo, bp, length, caplen);
374             return;
375         case ARPHRD_FRELAY:
376             linkaddr = LINKADDR_FRELAY;
377             break;
378         default:
379             linkaddr = LINKADDR_ETHER;
380             break;
381 	}
382 
383 	ND_TCHECK_LEN(TPA(ap), PROTO_LEN(ap));
384 
385         if (!ndo->ndo_eflag) {
386             ND_PRINT("ARP, ");
387         }
388 
389         /* print hardware type/len and proto type/len */
390         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
391 	    PROTO_LEN(ap) != 4 ||
392             HRD_LEN(ap) == 0 ||
393             ndo->ndo_vflag) {
394             ND_PRINT("%s (len %u), %s (len %u)",
395                       tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
396                       HRD_LEN(ap),
397                       tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
398                       PROTO_LEN(ap));
399 
400             /* don't know about the address formats */
401             if (!ndo->ndo_vflag) {
402                 goto out;
403             }
404 	}
405 
406         /* print operation */
407         ND_PRINT("%s%s ",
408                ndo->ndo_vflag ? ", " : "",
409                tok2str(arpop_values, "Unknown (%u)", op));
410 
411 	switch (op) {
412 
413 	case ARPOP_REQUEST:
414 		ND_PRINT("who-has ");
415 		tpaddr_print_ip(ndo, ap, pro);
416 		if (isnonzero(ndo, (const u_char *)THA(ap), HRD_LEN(ap)))
417 			ND_PRINT(" (%s)",
418 				  GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
419 		ND_PRINT(" tell ");
420 		spaddr_print_ip(ndo, ap, pro);
421 		break;
422 
423 	case ARPOP_REPLY:
424 		spaddr_print_ip(ndo, ap, pro);
425 		ND_PRINT(" is-at %s",
426                           GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
427 		break;
428 
429 	case ARPOP_REVREQUEST:
430 		/*
431 		 * XXX - GET_LINKADDR_STRING() may return a pointer to
432 		 * a static buffer, so we only have one call to it per
433 		 * ND_PRINT() call.
434 		 *
435 		 * This should be done in a cleaner fashion.
436 		 */
437 		ND_PRINT("who-is %s",
438 			  GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
439 		ND_PRINT(" tell %s",
440 			  GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
441 		break;
442 
443 	case ARPOP_REVREPLY:
444 		ND_PRINT("%s at ",
445 			  GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
446 		tpaddr_print_ip(ndo, ap, pro);
447 		break;
448 
449 	case ARPOP_INVREQUEST:
450 		/*
451 		 * XXX - GET_LINKADDR_STRING() may return a pointer to
452 		 * a static buffer, so we only have one call to it per
453 		 * ND_PRINT() call.
454 		 *
455 		 * This should be done in a cleaner fashion.
456 		 */
457 		ND_PRINT("who-is %s",
458 			  GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
459 		ND_PRINT(" tell %s",
460 			  GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
461 		break;
462 
463 	case ARPOP_INVREPLY:
464 		ND_PRINT("%s at ",
465 			  GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
466 		spaddr_print_ip(ndo, ap, pro);
467 		break;
468 
469 	default:
470 		ND_DEFAULTPRINT((const u_char *)ap, caplen);
471 		return;
472 	}
473 
474  out:
475         ND_PRINT(", length %u", length);
476 }
477