xref: /freebsd/contrib/tcpdump/print-icmp.c (revision 545ddfbe7d4fe8adfb862903b24eac1d5896c1ef)
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  * $FreeBSD$
22  */
23 
24 #define NETDISSECT_REWORKED
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28 
29 #include <tcpdump-stdinc.h>
30 
31 #include <stdio.h>
32 #include <string.h>
33 
34 #include "interface.h"
35 #include "addrtoname.h"
36 #include "extract.h"			/* must come after interface.h */
37 
38 #include "ip.h"
39 #include "udp.h"
40 #include "ipproto.h"
41 #include "mpls.h"
42 
43 /*
44  * Interface Control Message Protocol Definitions.
45  * Per RFC 792, September 1981.
46  */
47 
48 /*
49  * Structure of an icmp header.
50  */
51 struct icmp {
52 	uint8_t  icmp_type;		/* type of message, see below */
53 	uint8_t  icmp_code;		/* type sub code */
54 	uint16_t icmp_cksum;		/* ones complement cksum of struct */
55 	union {
56 		uint8_t ih_pptr;			/* ICMP_PARAMPROB */
57 		struct in_addr ih_gwaddr;	/* ICMP_REDIRECT */
58 		struct ih_idseq {
59 			uint16_t icd_id;
60 			uint16_t icd_seq;
61 		} ih_idseq;
62 		uint32_t ih_void;
63 	} icmp_hun;
64 #define	icmp_pptr	icmp_hun.ih_pptr
65 #define	icmp_gwaddr	icmp_hun.ih_gwaddr
66 #define	icmp_id		icmp_hun.ih_idseq.icd_id
67 #define	icmp_seq	icmp_hun.ih_idseq.icd_seq
68 #define	icmp_void	icmp_hun.ih_void
69 	union {
70 		struct id_ts {
71 			uint32_t its_otime;
72 			uint32_t its_rtime;
73 			uint32_t its_ttime;
74 		} id_ts;
75 		struct id_ip  {
76 			struct ip idi_ip;
77 			/* options and then 64 bits of data */
78 		} id_ip;
79 		uint32_t id_mask;
80 		uint8_t id_data[1];
81 	} icmp_dun;
82 #define	icmp_otime	icmp_dun.id_ts.its_otime
83 #define	icmp_rtime	icmp_dun.id_ts.its_rtime
84 #define	icmp_ttime	icmp_dun.id_ts.its_ttime
85 #define	icmp_ip		icmp_dun.id_ip.idi_ip
86 #define	icmp_mask	icmp_dun.id_mask
87 #define	icmp_data	icmp_dun.id_data
88 };
89 
90 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
91 #define ICMP_MPLS_EXT_VERSION 2
92 
93 /*
94  * Lower bounds on packet lengths for various types.
95  * For the error advice packets must first insure that the
96  * packet is large enought to contain the returned ip header.
97  * Only then can we do the check to see if 64 bits of packet
98  * data have been returned, since we need to check the returned
99  * ip header length.
100  */
101 #define	ICMP_MINLEN	8				/* abs minimum */
102 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip))     /* draft-bonica-internet-icmp-08 */
103 #define	ICMP_TSLEN	(8 + 3 * sizeof (uint32_t))	/* timestamp */
104 #define	ICMP_MASKLEN	12				/* address mask */
105 #define	ICMP_ADVLENMIN	(8 + sizeof (struct ip) + 8)	/* min */
106 #define	ICMP_ADVLEN(p)	(8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
107 	/* N.B.: must separately check that ip_hl >= 5 */
108 
109 /*
110  * Definition of type and code field values.
111  */
112 #define	ICMP_ECHOREPLY		0		/* echo reply */
113 #define	ICMP_UNREACH		3		/* dest unreachable, codes: */
114 #define		ICMP_UNREACH_NET	0		/* bad net */
115 #define		ICMP_UNREACH_HOST	1		/* bad host */
116 #define		ICMP_UNREACH_PROTOCOL	2		/* bad protocol */
117 #define		ICMP_UNREACH_PORT	3		/* bad port */
118 #define		ICMP_UNREACH_NEEDFRAG	4		/* IP_DF caused drop */
119 #define		ICMP_UNREACH_SRCFAIL	5		/* src route failed */
120 #define		ICMP_UNREACH_NET_UNKNOWN 6		/* unknown net */
121 #define		ICMP_UNREACH_HOST_UNKNOWN 7		/* unknown host */
122 #define		ICMP_UNREACH_ISOLATED	8		/* src host isolated */
123 #define		ICMP_UNREACH_NET_PROHIB	9		/* prohibited access */
124 #define		ICMP_UNREACH_HOST_PROHIB 10		/* ditto */
125 #define		ICMP_UNREACH_TOSNET	11		/* bad tos for net */
126 #define		ICMP_UNREACH_TOSHOST	12		/* bad tos for host */
127 #define	ICMP_SOURCEQUENCH	4		/* packet lost, slow down */
128 #define	ICMP_REDIRECT		5		/* shorter route, codes: */
129 #define		ICMP_REDIRECT_NET	0		/* for network */
130 #define		ICMP_REDIRECT_HOST	1		/* for host */
131 #define		ICMP_REDIRECT_TOSNET	2		/* for tos and net */
132 #define		ICMP_REDIRECT_TOSHOST	3		/* for tos and host */
133 #define	ICMP_ECHO		8		/* echo service */
134 #define	ICMP_ROUTERADVERT	9		/* router advertisement */
135 #define	ICMP_ROUTERSOLICIT	10		/* router solicitation */
136 #define	ICMP_TIMXCEED		11		/* time exceeded, code: */
137 #define		ICMP_TIMXCEED_INTRANS	0		/* ttl==0 in transit */
138 #define		ICMP_TIMXCEED_REASS	1		/* ttl==0 in reass */
139 #define	ICMP_PARAMPROB		12		/* ip header bad */
140 #define		ICMP_PARAMPROB_OPTABSENT 1		/* req. opt. absent */
141 #define	ICMP_TSTAMP		13		/* timestamp request */
142 #define	ICMP_TSTAMPREPLY	14		/* timestamp reply */
143 #define	ICMP_IREQ		15		/* information request */
144 #define	ICMP_IREQREPLY		16		/* information reply */
145 #define	ICMP_MASKREQ		17		/* address mask request */
146 #define	ICMP_MASKREPLY		18		/* address mask reply */
147 
148 #define	ICMP_MAXTYPE		18
149 
150 #define	ICMP_INFOTYPE(type) \
151 	((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
152 	(type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
153 	(type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
154 	(type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
155 	(type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
156 #define	ICMP_MPLS_EXT_TYPE(type) \
157 	((type) == ICMP_UNREACH || \
158          (type) == ICMP_TIMXCEED || \
159          (type) == ICMP_PARAMPROB)
160 /* rfc1700 */
161 #ifndef ICMP_UNREACH_NET_UNKNOWN
162 #define ICMP_UNREACH_NET_UNKNOWN	6	/* destination net unknown */
163 #endif
164 #ifndef ICMP_UNREACH_HOST_UNKNOWN
165 #define ICMP_UNREACH_HOST_UNKNOWN	7	/* destination host unknown */
166 #endif
167 #ifndef ICMP_UNREACH_ISOLATED
168 #define ICMP_UNREACH_ISOLATED		8	/* source host isolated */
169 #endif
170 #ifndef ICMP_UNREACH_NET_PROHIB
171 #define ICMP_UNREACH_NET_PROHIB		9	/* admin prohibited net */
172 #endif
173 #ifndef ICMP_UNREACH_HOST_PROHIB
174 #define ICMP_UNREACH_HOST_PROHIB	10	/* admin prohibited host */
175 #endif
176 #ifndef ICMP_UNREACH_TOSNET
177 #define ICMP_UNREACH_TOSNET		11	/* tos prohibited net */
178 #endif
179 #ifndef ICMP_UNREACH_TOSHOST
180 #define ICMP_UNREACH_TOSHOST		12	/* tos prohibited host */
181 #endif
182 
183 /* rfc1716 */
184 #ifndef ICMP_UNREACH_FILTER_PROHIB
185 #define ICMP_UNREACH_FILTER_PROHIB	13	/* admin prohibited filter */
186 #endif
187 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
188 #define ICMP_UNREACH_HOST_PRECEDENCE	14	/* host precedence violation */
189 #endif
190 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
191 #define ICMP_UNREACH_PRECEDENCE_CUTOFF	15	/* precedence cutoff */
192 #endif
193 
194 /* Most of the icmp types */
195 static const struct tok icmp2str[] = {
196 	{ ICMP_ECHOREPLY,		"echo reply" },
197 	{ ICMP_SOURCEQUENCH,		"source quench" },
198 	{ ICMP_ECHO,			"echo request" },
199 	{ ICMP_ROUTERSOLICIT,		"router solicitation" },
200 	{ ICMP_TSTAMP,			"time stamp request" },
201 	{ ICMP_TSTAMPREPLY,		"time stamp reply" },
202 	{ ICMP_IREQ,			"information request" },
203 	{ ICMP_IREQREPLY,		"information reply" },
204 	{ ICMP_MASKREQ,			"address mask request" },
205 	{ 0,				NULL }
206 };
207 
208 /* Formats for most of the ICMP_UNREACH codes */
209 static const struct tok unreach2str[] = {
210 	{ ICMP_UNREACH_NET,		"net %s unreachable" },
211 	{ ICMP_UNREACH_HOST,		"host %s unreachable" },
212 	{ ICMP_UNREACH_SRCFAIL,
213 	    "%s unreachable - source route failed" },
214 	{ ICMP_UNREACH_NET_UNKNOWN,	"net %s unreachable - unknown" },
215 	{ ICMP_UNREACH_HOST_UNKNOWN,	"host %s unreachable - unknown" },
216 	{ ICMP_UNREACH_ISOLATED,
217 	    "%s unreachable - source host isolated" },
218 	{ ICMP_UNREACH_NET_PROHIB,
219 	    "net %s unreachable - admin prohibited" },
220 	{ ICMP_UNREACH_HOST_PROHIB,
221 	    "host %s unreachable - admin prohibited" },
222 	{ ICMP_UNREACH_TOSNET,
223 	    "net %s unreachable - tos prohibited" },
224 	{ ICMP_UNREACH_TOSHOST,
225 	    "host %s unreachable - tos prohibited" },
226 	{ ICMP_UNREACH_FILTER_PROHIB,
227 	    "host %s unreachable - admin prohibited filter" },
228 	{ ICMP_UNREACH_HOST_PRECEDENCE,
229 	    "host %s unreachable - host precedence violation" },
230 	{ ICMP_UNREACH_PRECEDENCE_CUTOFF,
231 	    "host %s unreachable - precedence cutoff" },
232 	{ 0,				NULL }
233 };
234 
235 /* Formats for the ICMP_REDIRECT codes */
236 static const struct tok type2str[] = {
237 	{ ICMP_REDIRECT_NET,		"redirect %s to net %s" },
238 	{ ICMP_REDIRECT_HOST,		"redirect %s to host %s" },
239 	{ ICMP_REDIRECT_TOSNET,		"redirect-tos %s to net %s" },
240 	{ ICMP_REDIRECT_TOSHOST,	"redirect-tos %s to host %s" },
241 	{ 0,				NULL }
242 };
243 
244 /* rfc1191 */
245 struct mtu_discovery {
246 	uint16_t unused;
247 	uint16_t nexthopmtu;
248 };
249 
250 /* rfc1256 */
251 struct ih_rdiscovery {
252 	uint8_t ird_addrnum;
253 	uint8_t ird_addrsiz;
254 	uint16_t ird_lifetime;
255 };
256 
257 struct id_rdiscovery {
258 	uint32_t ird_addr;
259 	uint32_t ird_pref;
260 };
261 
262 /*
263  * draft-bonica-internet-icmp-08
264  *
265  * The Destination Unreachable, Time Exceeded
266  * and Parameter Problem messages are slighly changed as per
267  * the above draft. A new Length field gets added to give
268  * the caller an idea about the length of the piggypacked
269  * IP packet before the MPLS extension header starts.
270  *
271  * The Length field represents length of the padded "original datagram"
272  * field  measured in 32-bit words.
273  *
274  * 0                   1                   2                   3
275  * 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
276  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
277  * |     Type      |     Code      |          Checksum             |
278  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
279  * |     unused    |    Length     |          unused               |
280  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
281  * |      Internet Header + leading octets of original datagram    |
282  * |                                                               |
283  * |                           //                                  |
284  * |                                                               |
285  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
286  */
287 
288 struct icmp_ext_t {
289     uint8_t icmp_type;
290     uint8_t icmp_code;
291     uint8_t icmp_checksum[2];
292     uint8_t icmp_reserved;
293     uint8_t icmp_length;
294     uint8_t icmp_reserved2[2];
295     uint8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
296     uint8_t icmp_ext_version_res[2];
297     uint8_t icmp_ext_checksum[2];
298     uint8_t icmp_ext_data[1];
299 };
300 
301 struct icmp_mpls_ext_object_header_t {
302     uint8_t length[2];
303     uint8_t class_num;
304     uint8_t ctype;
305 };
306 
307 static const struct tok icmp_mpls_ext_obj_values[] = {
308     { 1, "MPLS Stack Entry" },
309     { 2, "Extended Payload" },
310     { 0, NULL}
311 };
312 
313 /* prototypes */
314 const char *icmp_tstamp_print(u_int);
315 
316 /* print the milliseconds since midnight UTC */
317 const char *
318 icmp_tstamp_print(u_int tstamp) {
319     u_int msec,sec,min,hrs;
320 
321     static char buf[64];
322 
323     msec = tstamp % 1000;
324     sec = tstamp / 1000;
325     min = sec / 60; sec -= min * 60;
326     hrs = min / 60; min -= hrs * 60;
327     snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
328     return buf;
329 }
330 
331 void
332 icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
333            int fragmented)
334 {
335 	char *cp;
336 	const struct icmp *dp;
337         const struct icmp_ext_t *ext_dp;
338 	const struct ip *ip;
339 	const char *str, *fmt;
340 	const struct ip *oip;
341 	const struct udphdr *ouh;
342         const uint8_t *obj_tptr;
343         uint32_t raw_label;
344         const u_char *snapend_save;
345 	const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
346 	u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
347 	char buf[MAXHOSTNAMELEN + 100];
348 	struct cksum_vec vec[1];
349 
350 	dp = (struct icmp *)bp;
351         ext_dp = (struct icmp_ext_t *)bp;
352 	ip = (struct ip *)bp2;
353 	str = buf;
354 
355 	ND_TCHECK(dp->icmp_code);
356 	switch (dp->icmp_type) {
357 
358 	case ICMP_ECHO:
359 	case ICMP_ECHOREPLY:
360 		ND_TCHECK(dp->icmp_seq);
361 		(void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
362                                dp->icmp_type == ICMP_ECHO ?
363                                "request" : "reply",
364                                EXTRACT_16BITS(&dp->icmp_id),
365                                EXTRACT_16BITS(&dp->icmp_seq));
366 		break;
367 
368 	case ICMP_UNREACH:
369 		ND_TCHECK(dp->icmp_ip.ip_dst);
370 		switch (dp->icmp_code) {
371 
372 		case ICMP_UNREACH_PROTOCOL:
373 			ND_TCHECK(dp->icmp_ip.ip_p);
374 			(void)snprintf(buf, sizeof(buf),
375 			    "%s protocol %d unreachable",
376 			    ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
377 			    dp->icmp_ip.ip_p);
378 			break;
379 
380 		case ICMP_UNREACH_PORT:
381 			ND_TCHECK(dp->icmp_ip.ip_p);
382 			oip = &dp->icmp_ip;
383 			hlen = IP_HL(oip) * 4;
384 			ouh = (struct udphdr *)(((u_char *)oip) + hlen);
385 			ND_TCHECK(ouh->uh_dport);
386 			dport = EXTRACT_16BITS(&ouh->uh_dport);
387 			switch (oip->ip_p) {
388 
389 			case IPPROTO_TCP:
390 				(void)snprintf(buf, sizeof(buf),
391 					"%s tcp port %s unreachable",
392 					ipaddr_string(ndo, &oip->ip_dst),
393 					tcpport_string(dport));
394 				break;
395 
396 			case IPPROTO_UDP:
397 				(void)snprintf(buf, sizeof(buf),
398 					"%s udp port %s unreachable",
399 					ipaddr_string(ndo, &oip->ip_dst),
400 					udpport_string(dport));
401 				break;
402 
403 			default:
404 				(void)snprintf(buf, sizeof(buf),
405 					"%s protocol %d port %d unreachable",
406 					ipaddr_string(ndo, &oip->ip_dst),
407 					oip->ip_p, dport);
408 				break;
409 			}
410 			break;
411 
412 		case ICMP_UNREACH_NEEDFRAG:
413 		    {
414 			register const struct mtu_discovery *mp;
415 			mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void;
416 			mtu = EXTRACT_16BITS(&mp->nexthopmtu);
417 			if (mtu) {
418 				(void)snprintf(buf, sizeof(buf),
419 				    "%s unreachable - need to frag (mtu %d)",
420 				    ipaddr_string(ndo, &dp->icmp_ip.ip_dst), mtu);
421 			} else {
422 				(void)snprintf(buf, sizeof(buf),
423 				    "%s unreachable - need to frag",
424 				    ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
425 			}
426 		    }
427 			break;
428 
429 		default:
430 			fmt = tok2str(unreach2str, "#%d %%s unreachable",
431 			    dp->icmp_code);
432 			(void)snprintf(buf, sizeof(buf), fmt,
433 			    ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
434 			break;
435 		}
436 		break;
437 
438 	case ICMP_REDIRECT:
439 		ND_TCHECK(dp->icmp_ip.ip_dst);
440 		fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
441 		    dp->icmp_code);
442 		(void)snprintf(buf, sizeof(buf), fmt,
443 		    ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
444 		    ipaddr_string(ndo, &dp->icmp_gwaddr));
445 		break;
446 
447 	case ICMP_ROUTERADVERT:
448 	    {
449 		register const struct ih_rdiscovery *ihp;
450 		register const struct id_rdiscovery *idp;
451 		u_int lifetime, num, size;
452 
453 		(void)snprintf(buf, sizeof(buf), "router advertisement");
454 		cp = buf + strlen(buf);
455 
456 		ihp = (struct ih_rdiscovery *)&dp->icmp_void;
457 		ND_TCHECK(*ihp);
458 		(void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
459 		cp = buf + strlen(buf);
460 		lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
461 		if (lifetime < 60) {
462 			(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
463 			    lifetime);
464 		} else if (lifetime < 60 * 60) {
465 			(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
466 			    lifetime / 60, lifetime % 60);
467 		} else {
468 			(void)snprintf(cp, sizeof(buf) - (cp - buf),
469 			    "%u:%02u:%02u",
470 			    lifetime / 3600,
471 			    (lifetime % 3600) / 60,
472 			    lifetime % 60);
473 		}
474 		cp = buf + strlen(buf);
475 
476 		num = ihp->ird_addrnum;
477 		(void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
478 		cp = buf + strlen(buf);
479 
480 		size = ihp->ird_addrsiz;
481 		if (size != 2) {
482 			(void)snprintf(cp, sizeof(buf) - (cp - buf),
483 			    " [size %d]", size);
484 			break;
485 		}
486 		idp = (struct id_rdiscovery *)&dp->icmp_data;
487 		while (num-- > 0) {
488 			ND_TCHECK(*idp);
489 			(void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
490 			    ipaddr_string(ndo, &idp->ird_addr),
491 			    EXTRACT_32BITS(&idp->ird_pref));
492 			cp = buf + strlen(buf);
493 			++idp;
494 		}
495 	    }
496 		break;
497 
498 	case ICMP_TIMXCEED:
499 		ND_TCHECK(dp->icmp_ip.ip_dst);
500 		switch (dp->icmp_code) {
501 
502 		case ICMP_TIMXCEED_INTRANS:
503 			str = "time exceeded in-transit";
504 			break;
505 
506 		case ICMP_TIMXCEED_REASS:
507 			str = "ip reassembly time exceeded";
508 			break;
509 
510 		default:
511 			(void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
512 			    dp->icmp_code);
513 			break;
514 		}
515 		break;
516 
517 	case ICMP_PARAMPROB:
518 		if (dp->icmp_code)
519 			(void)snprintf(buf, sizeof(buf),
520 			    "parameter problem - code %d", dp->icmp_code);
521 		else {
522 			ND_TCHECK(dp->icmp_pptr);
523 			(void)snprintf(buf, sizeof(buf),
524 			    "parameter problem - octet %d", dp->icmp_pptr);
525 		}
526 		break;
527 
528 	case ICMP_MASKREPLY:
529 		ND_TCHECK(dp->icmp_mask);
530 		(void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
531 		    EXTRACT_32BITS(&dp->icmp_mask));
532 		break;
533 
534 	case ICMP_TSTAMP:
535 		ND_TCHECK(dp->icmp_seq);
536 		(void)snprintf(buf, sizeof(buf),
537 		    "time stamp query id %u seq %u",
538 		    EXTRACT_16BITS(&dp->icmp_id),
539 		    EXTRACT_16BITS(&dp->icmp_seq));
540 		break;
541 
542 	case ICMP_TSTAMPREPLY:
543 		ND_TCHECK(dp->icmp_ttime);
544 		(void)snprintf(buf, sizeof(buf),
545 		    "time stamp reply id %u seq %u: org %s",
546                                EXTRACT_16BITS(&dp->icmp_id),
547                                EXTRACT_16BITS(&dp->icmp_seq),
548                                icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
549 
550                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
551                          icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
552                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
553                          icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
554                 break;
555 
556 	default:
557 		str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
558 		break;
559 	}
560 	ND_PRINT((ndo, "ICMP %s, length %u", str, plen));
561 	if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
562 		uint16_t sum, icmp_sum;
563 		struct cksum_vec vec[1];
564 		if (ND_TTEST2(*bp, plen)) {
565 			vec[0].ptr = (const uint8_t *)(void *)dp;
566 			vec[0].len = plen;
567 			sum = in_cksum(vec, 1);
568 			if (sum != 0) {
569 				icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
570 				ND_PRINT((ndo, " (wrong icmp cksum %x (->%x)!)",
571 					     icmp_sum,
572 					     in_cksum_shouldbe(icmp_sum, sum)));
573 			}
574 		}
575 	}
576 
577         /*
578          * print the remnants of the IP packet.
579          * save the snaplength as this may get overidden in the IP printer.
580          */
581 	if (ndo->ndo_vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
582 		bp += 8;
583 		ND_PRINT((ndo, "\n\t"));
584 		ip = (struct ip *)bp;
585 		ndo->ndo_snaplen = ndo->ndo_snapend - bp;
586                 snapend_save = ndo->ndo_snapend;
587 		ip_print(ndo, bp, EXTRACT_16BITS(&ip->ip_len));
588                 ndo->ndo_snapend = snapend_save;
589 	}
590 
591         /*
592          * Attempt to decode the MPLS extensions only for some ICMP types.
593          */
594         if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
595 
596             ND_TCHECK(*ext_dp);
597 
598             /*
599              * Check first if the mpls extension header shows a non-zero length.
600              * If the length field is not set then silently verify the checksum
601              * to check if an extension header is present. This is expedient,
602              * however not all implementations set the length field proper.
603              */
604             if (!ext_dp->icmp_length) {
605                 vec[0].ptr = (const uint8_t *)(void *)&ext_dp->icmp_ext_version_res;
606                 vec[0].len = plen - ICMP_EXTD_MINLEN;
607                 if (in_cksum(vec, 1)) {
608                     return;
609                 }
610             }
611 
612             ND_PRINT((ndo, "\n\tMPLS extension v%u",
613                    ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res))));
614 
615             /*
616              * Sanity checking of the header.
617              */
618             if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
619                 ICMP_MPLS_EXT_VERSION) {
620                 ND_PRINT((ndo, " packet not supported"));
621                 return;
622             }
623 
624             hlen = plen - ICMP_EXTD_MINLEN;
625             vec[0].ptr = (const uint8_t *)(void *)&ext_dp->icmp_ext_version_res;
626             vec[0].len = hlen;
627             ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
628                    EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
629                    in_cksum(vec, 1) ? "in" : "",
630                    hlen));
631 
632             hlen -= 4; /* subtract common header size */
633             obj_tptr = (uint8_t *)ext_dp->icmp_ext_data;
634 
635             while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
636 
637                 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
638                 ND_TCHECK(*icmp_mpls_ext_object_header);
639                 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
640                 obj_class_num = icmp_mpls_ext_object_header->class_num;
641                 obj_ctype = icmp_mpls_ext_object_header->ctype;
642                 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
643 
644                 ND_PRINT((ndo, "\n\t  %s Object (%u), Class-Type: %u, length %u",
645                        tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
646                        obj_class_num,
647                        obj_ctype,
648                        obj_tlen));
649 
650                 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
651 
652                 /* infinite loop protection */
653                 if ((obj_class_num == 0) ||
654                     (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
655                     return;
656                 }
657                 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
658 
659                 switch (obj_class_num) {
660                 case 1:
661                     switch(obj_ctype) {
662                     case 1:
663                         ND_TCHECK2(*obj_tptr, 4);
664                         raw_label = EXTRACT_32BITS(obj_tptr);
665                         ND_PRINT((ndo, "\n\t    label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)));
666                         if (MPLS_STACK(raw_label))
667                             ND_PRINT((ndo, ", [S]"));
668                         ND_PRINT((ndo, ", ttl %u", MPLS_TTL(raw_label)));
669                         break;
670                     default:
671                         print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
672                     }
673                     break;
674 
675                /*
676                 *  FIXME those are the defined objects that lack a decoder
677                 *  you are welcome to contribute code ;-)
678                 */
679                 case 2:
680                 default:
681                     print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
682                     break;
683                 }
684                 if (hlen < obj_tlen)
685                     break;
686                 hlen -= obj_tlen;
687                 obj_tptr += obj_tlen;
688             }
689         }
690 
691 	return;
692 trunc:
693 	ND_PRINT((ndo, "[|icmp]"));
694 }
695 /*
696  * Local Variables:
697  * c-style: whitesmith
698  * c-basic-offset: 8
699  * End:
700  */
701