print-icmp.c revision 302408 
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: stable/11/contrib/tcpdump/print-icmp.c 285275 2015-07-08 16:19:32Z pkelsey $
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_ERRTYPE(type) \
151	((type) == ICMP_UNREACH || (type) == ICMP_SOURCEQUENCH || \
152	(type) == ICMP_REDIRECT || (type) == ICMP_TIMXCEED || \
153	(type) == ICMP_PARAMPROB)
154#define	ICMP_MPLS_EXT_TYPE(type) \
155	((type) == ICMP_UNREACH || \
156         (type) == ICMP_TIMXCEED || \
157         (type) == ICMP_PARAMPROB)
158/* rfc1700 */
159#ifndef ICMP_UNREACH_NET_UNKNOWN
160#define ICMP_UNREACH_NET_UNKNOWN	6	/* destination net unknown */
161#endif
162#ifndef ICMP_UNREACH_HOST_UNKNOWN
163#define ICMP_UNREACH_HOST_UNKNOWN	7	/* destination host unknown */
164#endif
165#ifndef ICMP_UNREACH_ISOLATED
166#define ICMP_UNREACH_ISOLATED		8	/* source host isolated */
167#endif
168#ifndef ICMP_UNREACH_NET_PROHIB
169#define ICMP_UNREACH_NET_PROHIB		9	/* admin prohibited net */
170#endif
171#ifndef ICMP_UNREACH_HOST_PROHIB
172#define ICMP_UNREACH_HOST_PROHIB	10	/* admin prohibited host */
173#endif
174#ifndef ICMP_UNREACH_TOSNET
175#define ICMP_UNREACH_TOSNET		11	/* tos prohibited net */
176#endif
177#ifndef ICMP_UNREACH_TOSHOST
178#define ICMP_UNREACH_TOSHOST		12	/* tos prohibited host */
179#endif
180
181/* rfc1716 */
182#ifndef ICMP_UNREACH_FILTER_PROHIB
183#define ICMP_UNREACH_FILTER_PROHIB	13	/* admin prohibited filter */
184#endif
185#ifndef ICMP_UNREACH_HOST_PRECEDENCE
186#define ICMP_UNREACH_HOST_PRECEDENCE	14	/* host precedence violation */
187#endif
188#ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
189#define ICMP_UNREACH_PRECEDENCE_CUTOFF	15	/* precedence cutoff */
190#endif
191
192/* Most of the icmp types */
193static const struct tok icmp2str[] = {
194	{ ICMP_ECHOREPLY,		"echo reply" },
195	{ ICMP_SOURCEQUENCH,		"source quench" },
196	{ ICMP_ECHO,			"echo request" },
197	{ ICMP_ROUTERSOLICIT,		"router solicitation" },
198	{ ICMP_TSTAMP,			"time stamp request" },
199	{ ICMP_TSTAMPREPLY,		"time stamp reply" },
200	{ ICMP_IREQ,			"information request" },
201	{ ICMP_IREQREPLY,		"information reply" },
202	{ ICMP_MASKREQ,			"address mask request" },
203	{ 0,				NULL }
204};
205
206/* Formats for most of the ICMP_UNREACH codes */
207static const struct tok unreach2str[] = {
208	{ ICMP_UNREACH_NET,		"net %s unreachable" },
209	{ ICMP_UNREACH_HOST,		"host %s unreachable" },
210	{ ICMP_UNREACH_SRCFAIL,
211	    "%s unreachable - source route failed" },
212	{ ICMP_UNREACH_NET_UNKNOWN,	"net %s unreachable - unknown" },
213	{ ICMP_UNREACH_HOST_UNKNOWN,	"host %s unreachable - unknown" },
214	{ ICMP_UNREACH_ISOLATED,
215	    "%s unreachable - source host isolated" },
216	{ ICMP_UNREACH_NET_PROHIB,
217	    "net %s unreachable - admin prohibited" },
218	{ ICMP_UNREACH_HOST_PROHIB,
219	    "host %s unreachable - admin prohibited" },
220	{ ICMP_UNREACH_TOSNET,
221	    "net %s unreachable - tos prohibited" },
222	{ ICMP_UNREACH_TOSHOST,
223	    "host %s unreachable - tos prohibited" },
224	{ ICMP_UNREACH_FILTER_PROHIB,
225	    "host %s unreachable - admin prohibited filter" },
226	{ ICMP_UNREACH_HOST_PRECEDENCE,
227	    "host %s unreachable - host precedence violation" },
228	{ ICMP_UNREACH_PRECEDENCE_CUTOFF,
229	    "host %s unreachable - precedence cutoff" },
230	{ 0,				NULL }
231};
232
233/* Formats for the ICMP_REDIRECT codes */
234static const struct tok type2str[] = {
235	{ ICMP_REDIRECT_NET,		"redirect %s to net %s" },
236	{ ICMP_REDIRECT_HOST,		"redirect %s to host %s" },
237	{ ICMP_REDIRECT_TOSNET,		"redirect-tos %s to net %s" },
238	{ ICMP_REDIRECT_TOSHOST,	"redirect-tos %s to host %s" },
239	{ 0,				NULL }
240};
241
242/* rfc1191 */
243struct mtu_discovery {
244	uint16_t unused;
245	uint16_t nexthopmtu;
246};
247
248/* rfc1256 */
249struct ih_rdiscovery {
250	uint8_t ird_addrnum;
251	uint8_t ird_addrsiz;
252	uint16_t ird_lifetime;
253};
254
255struct id_rdiscovery {
256	uint32_t ird_addr;
257	uint32_t ird_pref;
258};
259
260/*
261 * draft-bonica-internet-icmp-08
262 *
263 * The Destination Unreachable, Time Exceeded
264 * and Parameter Problem messages are slighly changed as per
265 * the above draft. A new Length field gets added to give
266 * the caller an idea about the length of the piggypacked
267 * IP packet before the MPLS extension header starts.
268 *
269 * The Length field represents length of the padded "original datagram"
270 * field  measured in 32-bit words.
271 *
272 * 0                   1                   2                   3
273 * 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
274 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
275 * |     Type      |     Code      |          Checksum             |
276 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
277 * |     unused    |    Length     |          unused               |
278 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
279 * |      Internet Header + leading octets of original datagram    |
280 * |                                                               |
281 * |                           //                                  |
282 * |                                                               |
283 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
284 */
285
286struct icmp_ext_t {
287    uint8_t icmp_type;
288    uint8_t icmp_code;
289    uint8_t icmp_checksum[2];
290    uint8_t icmp_reserved;
291    uint8_t icmp_length;
292    uint8_t icmp_reserved2[2];
293    uint8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
294    uint8_t icmp_ext_version_res[2];
295    uint8_t icmp_ext_checksum[2];
296    uint8_t icmp_ext_data[1];
297};
298
299struct icmp_mpls_ext_object_header_t {
300    uint8_t length[2];
301    uint8_t class_num;
302    uint8_t ctype;
303};
304
305static const struct tok icmp_mpls_ext_obj_values[] = {
306    { 1, "MPLS Stack Entry" },
307    { 2, "Extended Payload" },
308    { 0, NULL}
309};
310
311/* prototypes */
312const char *icmp_tstamp_print(u_int);
313
314/* print the milliseconds since midnight UTC */
315const char *
316icmp_tstamp_print(u_int tstamp)
317{
318    u_int msec,sec,min,hrs;
319
320    static char buf[64];
321
322    msec = tstamp % 1000;
323    sec = tstamp / 1000;
324    min = sec / 60; sec -= min * 60;
325    hrs = min / 60; min -= hrs * 60;
326    snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
327    return buf;
328}
329
330void
331icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
332           int fragmented)
333{
334	char *cp;
335	const struct icmp *dp;
336        const struct icmp_ext_t *ext_dp;
337	const struct ip *ip;
338	const char *str, *fmt;
339	const struct ip *oip;
340	const struct udphdr *ouh;
341        const uint8_t *obj_tptr;
342        uint32_t raw_label;
343        const u_char *snapend_save;
344	const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
345	u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
346	char buf[MAXHOSTNAMELEN + 100];
347	struct cksum_vec vec[1];
348
349	dp = (struct icmp *)bp;
350        ext_dp = (struct icmp_ext_t *)bp;
351	ip = (struct ip *)bp2;
352	str = buf;
353
354	ND_TCHECK(dp->icmp_code);
355	switch (dp->icmp_type) {
356
357	case ICMP_ECHO:
358	case ICMP_ECHOREPLY:
359		ND_TCHECK(dp->icmp_seq);
360		(void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
361                               dp->icmp_type == ICMP_ECHO ?
362                               "request" : "reply",
363                               EXTRACT_16BITS(&dp->icmp_id),
364                               EXTRACT_16BITS(&dp->icmp_seq));
365		break;
366
367	case ICMP_UNREACH:
368		ND_TCHECK(dp->icmp_ip.ip_dst);
369		switch (dp->icmp_code) {
370
371		case ICMP_UNREACH_PROTOCOL:
372			ND_TCHECK(dp->icmp_ip.ip_p);
373			(void)snprintf(buf, sizeof(buf),
374			    "%s protocol %d unreachable",
375			    ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
376			    dp->icmp_ip.ip_p);
377			break;
378
379		case ICMP_UNREACH_PORT:
380			ND_TCHECK(dp->icmp_ip.ip_p);
381			oip = &dp->icmp_ip;
382			hlen = IP_HL(oip) * 4;
383			ouh = (struct udphdr *)(((u_char *)oip) + hlen);
384			ND_TCHECK(ouh->uh_dport);
385			dport = EXTRACT_16BITS(&ouh->uh_dport);
386			switch (oip->ip_p) {
387
388			case IPPROTO_TCP:
389				(void)snprintf(buf, sizeof(buf),
390					"%s tcp port %s unreachable",
391					ipaddr_string(ndo, &oip->ip_dst),
392					tcpport_string(dport));
393				break;
394
395			case IPPROTO_UDP:
396				(void)snprintf(buf, sizeof(buf),
397					"%s udp port %s unreachable",
398					ipaddr_string(ndo, &oip->ip_dst),
399					udpport_string(dport));
400				break;
401
402			default:
403				(void)snprintf(buf, sizeof(buf),
404					"%s protocol %d port %d unreachable",
405					ipaddr_string(ndo, &oip->ip_dst),
406					oip->ip_p, dport);
407				break;
408			}
409			break;
410
411		case ICMP_UNREACH_NEEDFRAG:
412		    {
413			register const struct mtu_discovery *mp;
414			mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void;
415			mtu = EXTRACT_16BITS(&mp->nexthopmtu);
416			if (mtu) {
417				(void)snprintf(buf, sizeof(buf),
418				    "%s unreachable - need to frag (mtu %d)",
419				    ipaddr_string(ndo, &dp->icmp_ip.ip_dst), mtu);
420			} else {
421				(void)snprintf(buf, sizeof(buf),
422				    "%s unreachable - need to frag",
423				    ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
424			}
425		    }
426			break;
427
428		default:
429			fmt = tok2str(unreach2str, "#%d %%s unreachable",
430			    dp->icmp_code);
431			(void)snprintf(buf, sizeof(buf), fmt,
432			    ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
433			break;
434		}
435		break;
436
437	case ICMP_REDIRECT:
438		ND_TCHECK(dp->icmp_ip.ip_dst);
439		fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
440		    dp->icmp_code);
441		(void)snprintf(buf, sizeof(buf), fmt,
442		    ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
443		    ipaddr_string(ndo, &dp->icmp_gwaddr));
444		break;
445
446	case ICMP_ROUTERADVERT:
447	    {
448		register const struct ih_rdiscovery *ihp;
449		register const struct id_rdiscovery *idp;
450		u_int lifetime, num, size;
451
452		(void)snprintf(buf, sizeof(buf), "router advertisement");
453		cp = buf + strlen(buf);
454
455		ihp = (struct ih_rdiscovery *)&dp->icmp_void;
456		ND_TCHECK(*ihp);
457		(void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
458		cp = buf + strlen(buf);
459		lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
460		if (lifetime < 60) {
461			(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
462			    lifetime);
463		} else if (lifetime < 60 * 60) {
464			(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
465			    lifetime / 60, lifetime % 60);
466		} else {
467			(void)snprintf(cp, sizeof(buf) - (cp - buf),
468			    "%u:%02u:%02u",
469			    lifetime / 3600,
470			    (lifetime % 3600) / 60,
471			    lifetime % 60);
472		}
473		cp = buf + strlen(buf);
474
475		num = ihp->ird_addrnum;
476		(void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
477		cp = buf + strlen(buf);
478
479		size = ihp->ird_addrsiz;
480		if (size != 2) {
481			(void)snprintf(cp, sizeof(buf) - (cp - buf),
482			    " [size %d]", size);
483			break;
484		}
485		idp = (struct id_rdiscovery *)&dp->icmp_data;
486		while (num-- > 0) {
487			ND_TCHECK(*idp);
488			(void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
489			    ipaddr_string(ndo, &idp->ird_addr),
490			    EXTRACT_32BITS(&idp->ird_pref));
491			cp = buf + strlen(buf);
492			++idp;
493		}
494	    }
495		break;
496
497	case ICMP_TIMXCEED:
498		ND_TCHECK(dp->icmp_ip.ip_dst);
499		switch (dp->icmp_code) {
500
501		case ICMP_TIMXCEED_INTRANS:
502			str = "time exceeded in-transit";
503			break;
504
505		case ICMP_TIMXCEED_REASS:
506			str = "ip reassembly time exceeded";
507			break;
508
509		default:
510			(void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
511			    dp->icmp_code);
512			break;
513		}
514		break;
515
516	case ICMP_PARAMPROB:
517		if (dp->icmp_code)
518			(void)snprintf(buf, sizeof(buf),
519			    "parameter problem - code %d", dp->icmp_code);
520		else {
521			ND_TCHECK(dp->icmp_pptr);
522			(void)snprintf(buf, sizeof(buf),
523			    "parameter problem - octet %d", dp->icmp_pptr);
524		}
525		break;
526
527	case ICMP_MASKREPLY:
528		ND_TCHECK(dp->icmp_mask);
529		(void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
530		    EXTRACT_32BITS(&dp->icmp_mask));
531		break;
532
533	case ICMP_TSTAMP:
534		ND_TCHECK(dp->icmp_seq);
535		(void)snprintf(buf, sizeof(buf),
536		    "time stamp query id %u seq %u",
537		    EXTRACT_16BITS(&dp->icmp_id),
538		    EXTRACT_16BITS(&dp->icmp_seq));
539		break;
540
541	case ICMP_TSTAMPREPLY:
542		ND_TCHECK(dp->icmp_ttime);
543		(void)snprintf(buf, sizeof(buf),
544		    "time stamp reply id %u seq %u: org %s",
545                               EXTRACT_16BITS(&dp->icmp_id),
546                               EXTRACT_16BITS(&dp->icmp_seq),
547                               icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
548
549                (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
550                         icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
551                (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
552                         icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
553                break;
554
555	default:
556		str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
557		break;
558	}
559	ND_PRINT((ndo, "ICMP %s, length %u", str, plen));
560	if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
561		uint16_t sum, icmp_sum;
562		struct cksum_vec vec[1];
563		if (ND_TTEST2(*bp, plen)) {
564			vec[0].ptr = (const uint8_t *)(void *)dp;
565			vec[0].len = plen;
566			sum = in_cksum(vec, 1);
567			if (sum != 0) {
568				icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
569				ND_PRINT((ndo, " (wrong icmp cksum %x (->%x)!)",
570					     icmp_sum,
571					     in_cksum_shouldbe(icmp_sum, sum)));
572			}
573		}
574	}
575
576        /*
577         * print the remnants of the IP packet.
578         * save the snaplength as this may get overidden in the IP printer.
579         */
580	if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(dp->icmp_type)) {
581		bp += 8;
582		ND_PRINT((ndo, "\n\t"));
583		ip = (struct ip *)bp;
584		ndo->ndo_snaplen = ndo->ndo_snapend - bp;
585                snapend_save = ndo->ndo_snapend;
586		ip_print(ndo, bp, EXTRACT_16BITS(&ip->ip_len));
587                ndo->ndo_snapend = snapend_save;
588	}
589
590        /*
591         * Attempt to decode the MPLS extensions only for some ICMP types.
592         */
593        if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
594
595            ND_TCHECK(*ext_dp);
596
597            /*
598             * Check first if the mpls extension header shows a non-zero length.
599             * If the length field is not set then silently verify the checksum
600             * to check if an extension header is present. This is expedient,
601             * however not all implementations set the length field proper.
602             */
603            if (!ext_dp->icmp_length) {
604                vec[0].ptr = (const uint8_t *)(void *)&ext_dp->icmp_ext_version_res;
605                vec[0].len = plen - ICMP_EXTD_MINLEN;
606                if (in_cksum(vec, 1)) {
607                    return;
608                }
609            }
610
611            ND_PRINT((ndo, "\n\tMPLS extension v%u",
612                   ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res))));
613
614            /*
615             * Sanity checking of the header.
616             */
617            if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
618                ICMP_MPLS_EXT_VERSION) {
619                ND_PRINT((ndo, " packet not supported"));
620                return;
621            }
622
623            hlen = plen - ICMP_EXTD_MINLEN;
624            vec[0].ptr = (const uint8_t *)(void *)&ext_dp->icmp_ext_version_res;
625            vec[0].len = hlen;
626            ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
627                   EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
628                   in_cksum(vec, 1) ? "in" : "",
629                   hlen));
630
631            hlen -= 4; /* subtract common header size */
632            obj_tptr = (uint8_t *)ext_dp->icmp_ext_data;
633
634            while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
635
636                icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
637                ND_TCHECK(*icmp_mpls_ext_object_header);
638                obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
639                obj_class_num = icmp_mpls_ext_object_header->class_num;
640                obj_ctype = icmp_mpls_ext_object_header->ctype;
641                obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
642
643                ND_PRINT((ndo, "\n\t  %s Object (%u), Class-Type: %u, length %u",
644                       tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
645                       obj_class_num,
646                       obj_ctype,
647                       obj_tlen));
648
649                hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
650
651                /* infinite loop protection */
652                if ((obj_class_num == 0) ||
653                    (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
654                    return;
655                }
656                obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
657
658                switch (obj_class_num) {
659                case 1:
660                    switch(obj_ctype) {
661                    case 1:
662                        ND_TCHECK2(*obj_tptr, 4);
663                        raw_label = EXTRACT_32BITS(obj_tptr);
664                        ND_PRINT((ndo, "\n\t    label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)));
665                        if (MPLS_STACK(raw_label))
666                            ND_PRINT((ndo, ", [S]"));
667                        ND_PRINT((ndo, ", ttl %u", MPLS_TTL(raw_label)));
668                        break;
669                    default:
670                        print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
671                    }
672                    break;
673
674               /*
675                *  FIXME those are the defined objects that lack a decoder
676                *  you are welcome to contribute code ;-)
677                */
678                case 2:
679                default:
680                    print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
681                    break;
682                }
683                if (hlen < obj_tlen)
684                    break;
685                hlen -= obj_tlen;
686                obj_tptr += obj_tlen;
687            }
688        }
689
690	return;
691trunc:
692	ND_PRINT((ndo, "[|icmp]"));
693}
694/*
695 * Local Variables:
696 * c-style: whitesmith
697 * c-basic-offset: 8
698 * End:
699 */
700