print-icmp.c revision 276788 
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: head/contrib/tcpdump/print-icmp.c 276788 2015-01-07 19:55:18Z delphij $
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 */
51struct 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 */
195static 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 */
209static 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 */
236static 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 */
245struct mtu_discovery {
246	uint16_t unused;
247	uint16_t nexthopmtu;
248};
249
250/* rfc1256 */
251struct ih_rdiscovery {
252	uint8_t ird_addrnum;
253	uint8_t ird_addrsiz;
254	uint16_t ird_lifetime;
255};
256
257struct 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
288struct 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
301struct icmp_mpls_ext_object_header_t {
302    uint8_t length[2];
303    uint8_t class_num;
304    uint8_t ctype;
305};
306
307static const struct tok icmp_mpls_ext_obj_values[] = {
308    { 1, "MPLS Stack Entry" },
309    { 2, "Extended Payload" },
310    { 0, NULL}
311};
312
313/* prototypes */
314const char *icmp_tstamp_print(u_int);
315
316/* print the milliseconds since midnight UTC */
317const char *
318icmp_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
331void
332icmp_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;
692trunc:
693	ND_PRINT((ndo, "[|icmp]"));
694}
695/*
696 * Local Variables:
697 * c-style: whitesmith
698 * c-basic-offset: 8
699 * End:
700 */
701