xref: /netbsd-src/external/bsd/tcpdump/dist/print-icmp.c (revision 7330f729ccf0bd976a06f95fad452fe774fc7fd1)
1 /*
2  * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
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-icmp.c,v 1.10 2019/10/01 16:06:16 christos Exp $");
25 #endif
26 
27 /* \summary: Internet Control Message Protocol (ICMP) printer */
28 
29 #ifdef HAVE_CONFIG_H
30 #include "config.h"
31 #endif
32 
33 #include <netdissect-stdinc.h>
34 
35 #include <stdio.h>
36 #include <string.h>
37 
38 #include "netdissect.h"
39 #include "addrtoname.h"
40 #include "extract.h"
41 
42 #include "ip.h"
43 #include "udp.h"
44 #include "ipproto.h"
45 #include "mpls.h"
46 
47 /*
48  * Interface Control Message Protocol Definitions.
49  * Per RFC 792, September 1981.
50  */
51 
52 /*
53  * Structure of an icmp header.
54  */
55 struct icmp {
56 	uint8_t  icmp_type;		/* type of message, see below */
57 	uint8_t  icmp_code;		/* type sub code */
58 	uint16_t icmp_cksum;		/* ones complement cksum of struct */
59 	union {
60 		uint8_t ih_pptr;			/* ICMP_PARAMPROB */
61 		struct in_addr ih_gwaddr;	/* ICMP_REDIRECT */
62 		struct ih_idseq {
63 			uint16_t icd_id;
64 			uint16_t icd_seq;
65 		} ih_idseq;
66 		uint32_t ih_void;
67 	} icmp_hun;
68 #define	icmp_pptr	icmp_hun.ih_pptr
69 #define	icmp_gwaddr	icmp_hun.ih_gwaddr
70 #define	icmp_id		icmp_hun.ih_idseq.icd_id
71 #define	icmp_seq	icmp_hun.ih_idseq.icd_seq
72 #define	icmp_void	icmp_hun.ih_void
73 	union {
74 		struct id_ts {
75 			uint32_t its_otime;
76 			uint32_t its_rtime;
77 			uint32_t its_ttime;
78 		} id_ts;
79 		struct id_ip  {
80 			struct ip idi_ip;
81 			/* options and then 64 bits of data */
82 		} id_ip;
83 		uint32_t id_mask;
84 		uint8_t id_data[1];
85 	} icmp_dun;
86 #define	icmp_otime	icmp_dun.id_ts.its_otime
87 #define	icmp_rtime	icmp_dun.id_ts.its_rtime
88 #define	icmp_ttime	icmp_dun.id_ts.its_ttime
89 #define	icmp_ip		icmp_dun.id_ip.idi_ip
90 #define	icmp_mask	icmp_dun.id_mask
91 #define	icmp_data	icmp_dun.id_data
92 };
93 
94 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
95 #define ICMP_MPLS_EXT_VERSION 2
96 
97 /*
98  * Lower bounds on packet lengths for various types.
99  * For the error advice packets must first insure that the
100  * packet is large enought to contain the returned ip header.
101  * Only then can we do the check to see if 64 bits of packet
102  * data have been returned, since we need to check the returned
103  * ip header length.
104  */
105 #define	ICMP_MINLEN	8				/* abs minimum */
106 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip))     /* draft-bonica-internet-icmp-08 */
107 #define	ICMP_TSLEN	(8 + 3 * sizeof (uint32_t))	/* timestamp */
108 #define	ICMP_MASKLEN	12				/* address mask */
109 #define	ICMP_ADVLENMIN	(8 + sizeof (struct ip) + 8)	/* min */
110 #define	ICMP_ADVLEN(p)	(8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
111 	/* N.B.: must separately check that ip_hl >= 5 */
112 
113 /*
114  * Definition of type and code field values.
115  */
116 #define	ICMP_ECHOREPLY		0		/* echo reply */
117 #define	ICMP_UNREACH		3		/* dest unreachable, codes: */
118 #define		ICMP_UNREACH_NET	0		/* bad net */
119 #define		ICMP_UNREACH_HOST	1		/* bad host */
120 #define		ICMP_UNREACH_PROTOCOL	2		/* bad protocol */
121 #define		ICMP_UNREACH_PORT	3		/* bad port */
122 #define		ICMP_UNREACH_NEEDFRAG	4		/* IP_DF caused drop */
123 #define		ICMP_UNREACH_SRCFAIL	5		/* src route failed */
124 #define		ICMP_UNREACH_NET_UNKNOWN 6		/* unknown net */
125 #define		ICMP_UNREACH_HOST_UNKNOWN 7		/* unknown host */
126 #define		ICMP_UNREACH_ISOLATED	8		/* src host isolated */
127 #define		ICMP_UNREACH_NET_PROHIB	9		/* prohibited access */
128 #define		ICMP_UNREACH_HOST_PROHIB 10		/* ditto */
129 #define		ICMP_UNREACH_TOSNET	11		/* bad tos for net */
130 #define		ICMP_UNREACH_TOSHOST	12		/* bad tos for host */
131 #define	ICMP_SOURCEQUENCH	4		/* packet lost, slow down */
132 #define	ICMP_REDIRECT		5		/* shorter route, codes: */
133 #define		ICMP_REDIRECT_NET	0		/* for network */
134 #define		ICMP_REDIRECT_HOST	1		/* for host */
135 #define		ICMP_REDIRECT_TOSNET	2		/* for tos and net */
136 #define		ICMP_REDIRECT_TOSHOST	3		/* for tos and host */
137 #define	ICMP_ECHO		8		/* echo service */
138 #define	ICMP_ROUTERADVERT	9		/* router advertisement */
139 #define	ICMP_ROUTERSOLICIT	10		/* router solicitation */
140 #define	ICMP_TIMXCEED		11		/* time exceeded, code: */
141 #define		ICMP_TIMXCEED_INTRANS	0		/* ttl==0 in transit */
142 #define		ICMP_TIMXCEED_REASS	1		/* ttl==0 in reass */
143 #define	ICMP_PARAMPROB		12		/* ip header bad */
144 #define		ICMP_PARAMPROB_OPTABSENT 1		/* req. opt. absent */
145 #define	ICMP_TSTAMP		13		/* timestamp request */
146 #define	ICMP_TSTAMPREPLY	14		/* timestamp reply */
147 #define	ICMP_IREQ		15		/* information request */
148 #define	ICMP_IREQREPLY		16		/* information reply */
149 #define	ICMP_MASKREQ		17		/* address mask request */
150 #define	ICMP_MASKREPLY		18		/* address mask reply */
151 
152 #define	ICMP_MAXTYPE		18
153 
154 #define ICMP_ERRTYPE(type) \
155 	((type) == ICMP_UNREACH || (type) == ICMP_SOURCEQUENCH || \
156 	(type) == ICMP_REDIRECT || (type) == ICMP_TIMXCEED || \
157 	(type) == ICMP_PARAMPROB)
158 #define	ICMP_MPLS_EXT_TYPE(type) \
159 	((type) == ICMP_UNREACH || \
160          (type) == ICMP_TIMXCEED || \
161          (type) == ICMP_PARAMPROB)
162 /* rfc1700 */
163 #ifndef ICMP_UNREACH_NET_UNKNOWN
164 #define ICMP_UNREACH_NET_UNKNOWN	6	/* destination net unknown */
165 #endif
166 #ifndef ICMP_UNREACH_HOST_UNKNOWN
167 #define ICMP_UNREACH_HOST_UNKNOWN	7	/* destination host unknown */
168 #endif
169 #ifndef ICMP_UNREACH_ISOLATED
170 #define ICMP_UNREACH_ISOLATED		8	/* source host isolated */
171 #endif
172 #ifndef ICMP_UNREACH_NET_PROHIB
173 #define ICMP_UNREACH_NET_PROHIB		9	/* admin prohibited net */
174 #endif
175 #ifndef ICMP_UNREACH_HOST_PROHIB
176 #define ICMP_UNREACH_HOST_PROHIB	10	/* admin prohibited host */
177 #endif
178 #ifndef ICMP_UNREACH_TOSNET
179 #define ICMP_UNREACH_TOSNET		11	/* tos prohibited net */
180 #endif
181 #ifndef ICMP_UNREACH_TOSHOST
182 #define ICMP_UNREACH_TOSHOST		12	/* tos prohibited host */
183 #endif
184 
185 /* rfc1716 */
186 #ifndef ICMP_UNREACH_FILTER_PROHIB
187 #define ICMP_UNREACH_FILTER_PROHIB	13	/* admin prohibited filter */
188 #endif
189 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
190 #define ICMP_UNREACH_HOST_PRECEDENCE	14	/* host precedence violation */
191 #endif
192 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
193 #define ICMP_UNREACH_PRECEDENCE_CUTOFF	15	/* precedence cutoff */
194 #endif
195 
196 /* Most of the icmp types */
197 static const struct tok icmp2str[] = {
198 	{ ICMP_ECHOREPLY,		"echo reply" },
199 	{ ICMP_SOURCEQUENCH,		"source quench" },
200 	{ ICMP_ECHO,			"echo request" },
201 	{ ICMP_ROUTERSOLICIT,		"router solicitation" },
202 	{ ICMP_TSTAMP,			"time stamp request" },
203 	{ ICMP_TSTAMPREPLY,		"time stamp reply" },
204 	{ ICMP_IREQ,			"information request" },
205 	{ ICMP_IREQREPLY,		"information reply" },
206 	{ ICMP_MASKREQ,			"address mask request" },
207 	{ 0,				NULL }
208 };
209 
210 /* Formats for most of the ICMP_UNREACH codes */
211 static const struct tok unreach2str[] = {
212 	{ ICMP_UNREACH_NET,		"net %s unreachable" },
213 	{ ICMP_UNREACH_HOST,		"host %s unreachable" },
214 	{ ICMP_UNREACH_SRCFAIL,
215 	    "%s unreachable - source route failed" },
216 	{ ICMP_UNREACH_NET_UNKNOWN,	"net %s unreachable - unknown" },
217 	{ ICMP_UNREACH_HOST_UNKNOWN,	"host %s unreachable - unknown" },
218 	{ ICMP_UNREACH_ISOLATED,
219 	    "%s unreachable - source host isolated" },
220 	{ ICMP_UNREACH_NET_PROHIB,
221 	    "net %s unreachable - admin prohibited" },
222 	{ ICMP_UNREACH_HOST_PROHIB,
223 	    "host %s unreachable - admin prohibited" },
224 	{ ICMP_UNREACH_TOSNET,
225 	    "net %s unreachable - tos prohibited" },
226 	{ ICMP_UNREACH_TOSHOST,
227 	    "host %s unreachable - tos prohibited" },
228 	{ ICMP_UNREACH_FILTER_PROHIB,
229 	    "host %s unreachable - admin prohibited filter" },
230 	{ ICMP_UNREACH_HOST_PRECEDENCE,
231 	    "host %s unreachable - host precedence violation" },
232 	{ ICMP_UNREACH_PRECEDENCE_CUTOFF,
233 	    "host %s unreachable - precedence cutoff" },
234 	{ 0,				NULL }
235 };
236 
237 /* Formats for the ICMP_REDIRECT codes */
238 static const struct tok type2str[] = {
239 	{ ICMP_REDIRECT_NET,		"redirect %s to net %s" },
240 	{ ICMP_REDIRECT_HOST,		"redirect %s to host %s" },
241 	{ ICMP_REDIRECT_TOSNET,		"redirect-tos %s to net %s" },
242 	{ ICMP_REDIRECT_TOSHOST,	"redirect-tos %s to host %s" },
243 	{ 0,				NULL }
244 };
245 
246 /* rfc1191 */
247 struct mtu_discovery {
248 	uint16_t unused;
249 	uint16_t nexthopmtu;
250 };
251 
252 /* rfc1256 */
253 struct ih_rdiscovery {
254 	uint8_t ird_addrnum;
255 	uint8_t ird_addrsiz;
256 	uint16_t ird_lifetime;
257 };
258 
259 struct id_rdiscovery {
260 	uint32_t ird_addr;
261 	uint32_t ird_pref;
262 };
263 
264 /*
265  * draft-bonica-internet-icmp-08
266  *
267  * The Destination Unreachable, Time Exceeded
268  * and Parameter Problem messages are slighly changed as per
269  * the above draft. A new Length field gets added to give
270  * the caller an idea about the length of the piggypacked
271  * IP packet before the MPLS extension header starts.
272  *
273  * The Length field represents length of the padded "original datagram"
274  * field  measured in 32-bit words.
275  *
276  * 0                   1                   2                   3
277  * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
278  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
279  * |     Type      |     Code      |          Checksum             |
280  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
281  * |     unused    |    Length     |          unused               |
282  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
283  * |      Internet Header + leading octets of original datagram    |
284  * |                                                               |
285  * |                           //                                  |
286  * |                                                               |
287  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
288  */
289 
290 struct icmp_ext_t {
291     uint8_t icmp_type;
292     uint8_t icmp_code;
293     uint8_t icmp_checksum[2];
294     uint8_t icmp_reserved;
295     uint8_t icmp_length;
296     uint8_t icmp_reserved2[2];
297     uint8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
298     uint8_t icmp_ext_version_res[2];
299     uint8_t icmp_ext_checksum[2];
300     uint8_t icmp_ext_data[1];
301 };
302 
303 struct icmp_mpls_ext_object_header_t {
304     uint8_t length[2];
305     uint8_t class_num;
306     uint8_t ctype;
307 };
308 
309 static const struct tok icmp_mpls_ext_obj_values[] = {
310     { 1, "MPLS Stack Entry" },
311     { 2, "Extended Payload" },
312     { 0, NULL}
313 };
314 
315 /* prototypes */
316 const char *icmp_tstamp_print(u_int);
317 
318 /* print the milliseconds since midnight UTC */
319 const char *
320 icmp_tstamp_print(u_int tstamp)
321 {
322     u_int msec,sec,min,hrs;
323 
324     static char buf[64];
325 
326     msec = tstamp % 1000;
327     sec = tstamp / 1000;
328     min = sec / 60; sec -= min * 60;
329     hrs = min / 60; min -= hrs * 60;
330     snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
331     return buf;
332 }
333 
334 void
335 icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
336            int fragmented)
337 {
338 	char *cp;
339 	const struct icmp *dp;
340         const struct icmp_ext_t *ext_dp;
341 	const struct ip *ip;
342 	const char *str, *fmt;
343 	const struct ip *oip;
344 	const struct udphdr *ouh;
345         const uint8_t *obj_tptr;
346         uint32_t raw_label;
347         const u_char *snapend_save;
348 	const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
349 	u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
350 	char buf[MAXHOSTNAMELEN + 100];
351 	struct cksum_vec vec[1];
352 
353 	dp = (const struct icmp *)bp;
354         ext_dp = (const struct icmp_ext_t *)bp;
355 	ip = (const struct ip *)bp2;
356 	str = buf;
357 
358 	ND_TCHECK(dp->icmp_code);
359 	switch (dp->icmp_type) {
360 
361 	case ICMP_ECHO:
362 	case ICMP_ECHOREPLY:
363 		ND_TCHECK(dp->icmp_seq);
364 		(void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
365                                dp->icmp_type == ICMP_ECHO ?
366                                "request" : "reply",
367                                EXTRACT_16BITS(&dp->icmp_id),
368                                EXTRACT_16BITS(&dp->icmp_seq));
369 		break;
370 
371 	case ICMP_UNREACH:
372 		ND_TCHECK(dp->icmp_ip.ip_dst);
373 		switch (dp->icmp_code) {
374 
375 		case ICMP_UNREACH_PROTOCOL:
376 			ND_TCHECK(dp->icmp_ip.ip_p);
377 			(void)snprintf(buf, sizeof(buf),
378 			    "%s protocol %d unreachable",
379 			    ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
380 			    dp->icmp_ip.ip_p);
381 			break;
382 
383 		case ICMP_UNREACH_PORT:
384 			ND_TCHECK(dp->icmp_ip.ip_p);
385 			oip = &dp->icmp_ip;
386 			hlen = IP_HL(oip) * 4;
387 			ouh = (const struct udphdr *)(((const u_char *)oip) + hlen);
388 			ND_TCHECK(ouh->uh_dport);
389 			dport = EXTRACT_16BITS(&ouh->uh_dport);
390 			switch (oip->ip_p) {
391 
392 			case IPPROTO_TCP:
393 				(void)snprintf(buf, sizeof(buf),
394 					"%s tcp port %s unreachable",
395 					ipaddr_string(ndo, &oip->ip_dst),
396 					tcpport_string(ndo, dport));
397 				break;
398 
399 			case IPPROTO_UDP:
400 				(void)snprintf(buf, sizeof(buf),
401 					"%s udp port %s unreachable",
402 					ipaddr_string(ndo, &oip->ip_dst),
403 					udpport_string(ndo, dport));
404 				break;
405 
406 			default:
407 				(void)snprintf(buf, sizeof(buf),
408 					"%s protocol %u port %u unreachable",
409 					ipaddr_string(ndo, &oip->ip_dst),
410 					oip->ip_p, dport);
411 				break;
412 			}
413 			break;
414 
415 		case ICMP_UNREACH_NEEDFRAG:
416 		    {
417 			register const struct mtu_discovery *mp;
418 			mp = (const struct mtu_discovery *)(const u_char *)&dp->icmp_void;
419 			mtu = EXTRACT_16BITS(&mp->nexthopmtu);
420 			if (mtu) {
421 				(void)snprintf(buf, sizeof(buf),
422 				    "%s unreachable - need to frag (mtu %d)",
423 				    ipaddr_string(ndo, &dp->icmp_ip.ip_dst), mtu);
424 			} else {
425 				(void)snprintf(buf, sizeof(buf),
426 				    "%s unreachable - need to frag",
427 				    ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
428 			}
429 		    }
430 			break;
431 
432 		default:
433 			fmt = tok2str(unreach2str, "#%d %%s unreachable",
434 			    dp->icmp_code);
435 			(void)snprintf(buf, sizeof(buf), fmt,
436 			    ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
437 			break;
438 		}
439 		break;
440 
441 	case ICMP_REDIRECT:
442 		ND_TCHECK(dp->icmp_ip.ip_dst);
443 		fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
444 		    dp->icmp_code);
445 		(void)snprintf(buf, sizeof(buf), fmt,
446 		    ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
447 		    ipaddr_string(ndo, &dp->icmp_gwaddr));
448 		break;
449 
450 	case ICMP_ROUTERADVERT:
451 	    {
452 		register const struct ih_rdiscovery *ihp;
453 		register const struct id_rdiscovery *idp;
454 		u_int lifetime, num, size;
455 
456 		(void)snprintf(buf, sizeof(buf), "router advertisement");
457 		cp = buf + strlen(buf);
458 
459 		ihp = (const struct ih_rdiscovery *)&dp->icmp_void;
460 		ND_TCHECK(*ihp);
461 		(void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
462 		cp = buf + strlen(buf);
463 		lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
464 		if (lifetime < 60) {
465 			(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
466 			    lifetime);
467 		} else if (lifetime < 60 * 60) {
468 			(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
469 			    lifetime / 60, lifetime % 60);
470 		} else {
471 			(void)snprintf(cp, sizeof(buf) - (cp - buf),
472 			    "%u:%02u:%02u",
473 			    lifetime / 3600,
474 			    (lifetime % 3600) / 60,
475 			    lifetime % 60);
476 		}
477 		cp = buf + strlen(buf);
478 
479 		num = ihp->ird_addrnum;
480 		(void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
481 		cp = buf + strlen(buf);
482 
483 		size = ihp->ird_addrsiz;
484 		if (size != 2) {
485 			(void)snprintf(cp, sizeof(buf) - (cp - buf),
486 			    " [size %d]", size);
487 			break;
488 		}
489 		idp = (const struct id_rdiscovery *)&dp->icmp_data;
490 		while (num-- > 0) {
491 			ND_TCHECK(*idp);
492 			(void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
493 			    ipaddr_string(ndo, &idp->ird_addr),
494 			    EXTRACT_32BITS(&idp->ird_pref));
495 			cp = buf + strlen(buf);
496 			++idp;
497 		}
498 	    }
499 		break;
500 
501 	case ICMP_TIMXCEED:
502 		ND_TCHECK(dp->icmp_ip.ip_dst);
503 		switch (dp->icmp_code) {
504 
505 		case ICMP_TIMXCEED_INTRANS:
506 			str = "time exceeded in-transit";
507 			break;
508 
509 		case ICMP_TIMXCEED_REASS:
510 			str = "ip reassembly time exceeded";
511 			break;
512 
513 		default:
514 			(void)snprintf(buf, sizeof(buf), "time exceeded-#%u",
515 			    dp->icmp_code);
516 			break;
517 		}
518 		break;
519 
520 	case ICMP_PARAMPROB:
521 		if (dp->icmp_code)
522 			(void)snprintf(buf, sizeof(buf),
523 			    "parameter problem - code %u", dp->icmp_code);
524 		else {
525 			ND_TCHECK(dp->icmp_pptr);
526 			(void)snprintf(buf, sizeof(buf),
527 			    "parameter problem - octet %u", dp->icmp_pptr);
528 		}
529 		break;
530 
531 	case ICMP_MASKREPLY:
532 		ND_TCHECK(dp->icmp_mask);
533 		(void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
534 		    EXTRACT_32BITS(&dp->icmp_mask));
535 		break;
536 
537 	case ICMP_TSTAMP:
538 		ND_TCHECK(dp->icmp_seq);
539 		(void)snprintf(buf, sizeof(buf),
540 		    "time stamp query id %u seq %u",
541 		    EXTRACT_16BITS(&dp->icmp_id),
542 		    EXTRACT_16BITS(&dp->icmp_seq));
543 		break;
544 
545 	case ICMP_TSTAMPREPLY:
546 		ND_TCHECK(dp->icmp_ttime);
547 		(void)snprintf(buf, sizeof(buf),
548 		    "time stamp reply id %u seq %u: org %s",
549                                EXTRACT_16BITS(&dp->icmp_id),
550                                EXTRACT_16BITS(&dp->icmp_seq),
551                                icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
552 
553                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
554                          icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
555                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
556                          icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
557                 break;
558 
559 	default:
560 		str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
561 		break;
562 	}
563 	ND_PRINT((ndo, "ICMP %s, length %u", str, plen));
564 	if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
565 		if (ND_TTEST2(*bp, plen)) {
566 			uint16_t sum;
567 
568 			vec[0].ptr = (const uint8_t *)(const void *)dp;
569 			vec[0].len = plen;
570 			sum = in_cksum(vec, 1);
571 			if (sum != 0) {
572 				uint16_t icmp_sum;
573 				ND_TCHECK_16BITS(&dp->icmp_cksum);
574 				icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
575 				ND_PRINT((ndo, " (wrong icmp cksum %x (->%x)!)",
576 					     icmp_sum,
577 					     in_cksum_shouldbe(icmp_sum, sum)));
578 			}
579 		}
580 	}
581 
582         /*
583          * print the remnants of the IP packet.
584          * save the snaplength as this may get overidden in the IP printer.
585          */
586 	if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(dp->icmp_type)) {
587 		bp += 8;
588 		ND_PRINT((ndo, "\n\t"));
589 		ip = (const struct ip *)bp;
590 		ndo->ndo_snaplen = ndo->ndo_snapend - bp;
591                 snapend_save = ndo->ndo_snapend;
592 		ND_TCHECK_16BITS(&ip->ip_len);
593 		ip_print(ndo, bp, EXTRACT_16BITS(&ip->ip_len));
594                 ndo->ndo_snapend = snapend_save;
595 	}
596 
597         /*
598          * Attempt to decode the MPLS extensions only for some ICMP types.
599          */
600         if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
601 
602             ND_TCHECK(*ext_dp);
603 
604             /*
605              * Check first if the mpls extension header shows a non-zero length.
606              * If the length field is not set then silently verify the checksum
607              * to check if an extension header is present. This is expedient,
608              * however not all implementations set the length field proper.
609              */
610             if (!ext_dp->icmp_length &&
611                 ND_TTEST2(ext_dp->icmp_ext_version_res, plen - ICMP_EXTD_MINLEN)) {
612                 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
613                 vec[0].len = plen - ICMP_EXTD_MINLEN;
614                 if (in_cksum(vec, 1)) {
615                     return;
616                 }
617             }
618 
619             ND_PRINT((ndo, "\n\tMPLS extension v%u",
620                    ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res))));
621 
622             /*
623              * Sanity checking of the header.
624              */
625             if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
626                 ICMP_MPLS_EXT_VERSION) {
627                 ND_PRINT((ndo, " packet not supported"));
628                 return;
629             }
630 
631             hlen = plen - ICMP_EXTD_MINLEN;
632             if (ND_TTEST2(ext_dp->icmp_ext_version_res, hlen)) {
633                 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
634                 vec[0].len = hlen;
635                 ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
636                        EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
637                        in_cksum(vec, 1) ? "in" : "",
638                        hlen));
639             }
640 
641             hlen -= 4; /* subtract common header size */
642             obj_tptr = (const uint8_t *)ext_dp->icmp_ext_data;
643 
644             while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
645 
646                 icmp_mpls_ext_object_header = (const struct icmp_mpls_ext_object_header_t *)obj_tptr;
647                 ND_TCHECK(*icmp_mpls_ext_object_header);
648                 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
649                 obj_class_num = icmp_mpls_ext_object_header->class_num;
650                 obj_ctype = icmp_mpls_ext_object_header->ctype;
651                 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
652 
653                 ND_PRINT((ndo, "\n\t  %s Object (%u), Class-Type: %u, length %u",
654                        tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
655                        obj_class_num,
656                        obj_ctype,
657                        obj_tlen));
658 
659                 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
660 
661                 /* infinite loop protection */
662                 if ((obj_class_num == 0) ||
663                     (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
664                     return;
665                 }
666                 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
667 
668                 switch (obj_class_num) {
669                 case 1:
670                     switch(obj_ctype) {
671                     case 1:
672                         ND_TCHECK2(*obj_tptr, 4);
673                         raw_label = EXTRACT_32BITS(obj_tptr);
674                         ND_PRINT((ndo, "\n\t    label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)));
675                         if (MPLS_STACK(raw_label))
676                             ND_PRINT((ndo, ", [S]"));
677                         ND_PRINT((ndo, ", ttl %u", MPLS_TTL(raw_label)));
678                         break;
679                     default:
680                         print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
681                     }
682                     break;
683 
684                /*
685                 *  FIXME those are the defined objects that lack a decoder
686                 *  you are welcome to contribute code ;-)
687                 */
688                 case 2:
689                 default:
690                     print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
691                     break;
692                 }
693                 if (hlen < obj_tlen)
694                     break;
695                 hlen -= obj_tlen;
696                 obj_tptr += obj_tlen;
697             }
698         }
699 
700 	return;
701 trunc:
702 	ND_PRINT((ndo, "[|icmp]"));
703 }
704 /*
705  * Local Variables:
706  * c-style: whitesmith
707  * c-basic-offset: 8
708  * End:
709  */
710