xref: /freebsd/usr.sbin/traceroute6/traceroute6.c (revision 3c4ba5f55438f7afd4f4b0b56f88f2bb505fd6a6)
1 /*	$KAME: traceroute6.c,v 1.68 2004/01/25 11:16:12 suz Exp $	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-3-Clause
5  *
6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the project nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 /*-
35  * Copyright (c) 1990, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  *
38  * This code is derived from software contributed to Berkeley by
39  * Van Jacobson.
40  *
41  * Redistribution and use in source and binary forms, with or without
42  * modification, are permitted provided that the following conditions
43  * are met:
44  * 1. Redistributions of source code must retain the above copyright
45  *    notice, this list of conditions and the following disclaimer.
46  * 2. Redistributions in binary form must reproduce the above copyright
47  *    notice, this list of conditions and the following disclaimer in the
48  *    documentation and/or other materials provided with the distribution.
49  * 3. Neither the name of the University nor the names of its contributors
50  *    may be used to endorse or promote products derived from this software
51  *    without specific prior written permission.
52  *
53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63  * SUCH DAMAGE.
64  */
65 
66 #ifndef lint
67 static const char copyright[] =
68 "@(#) Copyright (c) 1990, 1993\n\
69 	The Regents of the University of California.  All rights reserved.\n";
70 #endif /* not lint */
71 
72 #ifndef lint
73 #if 0
74 static char sccsid[] = "@(#)traceroute.c	8.1 (Berkeley) 6/6/93";
75 #endif
76 static const char rcsid[] =
77   "$FreeBSD$";
78 #endif /* not lint */
79 
80 /*
81  * traceroute host  - trace the route ip packets follow going to "host".
82  *
83  * Attempt to trace the route an ip packet would follow to some
84  * internet host.  We find out intermediate hops by launching probe
85  * packets with a small ttl (time to live) then listening for an
86  * icmp "time exceeded" reply from a gateway.  We start our probes
87  * with a ttl of one and increase by one until we get an icmp "port
88  * unreachable" (which means we got to "host") or hit a max (which
89  * defaults to 30 hops & can be changed with the -m flag).  Three
90  * probes (change with -q flag) are sent at each ttl setting and a
91  * line is printed showing the ttl, address of the gateway and
92  * round trip time of each probe.  If the probe answers come from
93  * different gateways, the address of each responding system will
94  * be printed.  If there is no response within a 5 sec. timeout
95  * interval (changed with the -w flag), a "*" is printed for that
96  * probe.
97  *
98  * Probe packets are UDP format.  We don't want the destination
99  * host to process them so the destination port is set to an
100  * unlikely value (if some clod on the destination is using that
101  * value, it can be changed with the -p flag).
102  *
103  * A sample use might be:
104  *
105  *     [yak 71]% traceroute nis.nsf.net.
106  *     traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 56 byte packet
107  *      1  helios.ee.lbl.gov (128.3.112.1)  19 ms  19 ms  0 ms
108  *      2  lilac-dmc.Berkeley.EDU (128.32.216.1)  39 ms  39 ms  19 ms
109  *      3  lilac-dmc.Berkeley.EDU (128.32.216.1)  39 ms  39 ms  19 ms
110  *      4  ccngw-ner-cc.Berkeley.EDU (128.32.136.23)  39 ms  40 ms  39 ms
111  *      5  ccn-nerif22.Berkeley.EDU (128.32.168.22)  39 ms  39 ms  39 ms
112  *      6  128.32.197.4 (128.32.197.4)  40 ms  59 ms  59 ms
113  *      7  131.119.2.5 (131.119.2.5)  59 ms  59 ms  59 ms
114  *      8  129.140.70.13 (129.140.70.13)  99 ms  99 ms  80 ms
115  *      9  129.140.71.6 (129.140.71.6)  139 ms  239 ms  319 ms
116  *     10  129.140.81.7 (129.140.81.7)  220 ms  199 ms  199 ms
117  *     11  nic.merit.edu (35.1.1.48)  239 ms  239 ms  239 ms
118  *
119  * Note that lines 2 & 3 are the same.  This is due to a buggy
120  * kernel on the 2nd hop system -- lbl-csam.arpa -- that forwards
121  * packets with a zero ttl.
122  *
123  * A more interesting example is:
124  *
125  *     [yak 72]% traceroute allspice.lcs.mit.edu.
126  *     traceroute to allspice.lcs.mit.edu (18.26.0.115), 30 hops max
127  *      1  helios.ee.lbl.gov (128.3.112.1)  0 ms  0 ms  0 ms
128  *      2  lilac-dmc.Berkeley.EDU (128.32.216.1)  19 ms  19 ms  19 ms
129  *      3  lilac-dmc.Berkeley.EDU (128.32.216.1)  39 ms  19 ms  19 ms
130  *      4  ccngw-ner-cc.Berkeley.EDU (128.32.136.23)  19 ms  39 ms  39 ms
131  *      5  ccn-nerif22.Berkeley.EDU (128.32.168.22)  20 ms  39 ms  39 ms
132  *      6  128.32.197.4 (128.32.197.4)  59 ms  119 ms  39 ms
133  *      7  131.119.2.5 (131.119.2.5)  59 ms  59 ms  39 ms
134  *      8  129.140.70.13 (129.140.70.13)  80 ms  79 ms  99 ms
135  *      9  129.140.71.6 (129.140.71.6)  139 ms  139 ms  159 ms
136  *     10  129.140.81.7 (129.140.81.7)  199 ms  180 ms  300 ms
137  *     11  129.140.72.17 (129.140.72.17)  300 ms  239 ms  239 ms
138  *     12  * * *
139  *     13  128.121.54.72 (128.121.54.72)  259 ms  499 ms  279 ms
140  *     14  * * *
141  *     15  * * *
142  *     16  * * *
143  *     17  * * *
144  *     18  ALLSPICE.LCS.MIT.EDU (18.26.0.115)  339 ms  279 ms  279 ms
145  *
146  * (I start to see why I'm having so much trouble with mail to
147  * MIT.)  Note that the gateways 12, 14, 15, 16 & 17 hops away
148  * either don't send ICMP "time exceeded" messages or send them
149  * with a ttl too small to reach us.  14 - 17 are running the
150  * MIT C Gateway code that doesn't send "time exceeded"s.  God
151  * only knows what's going on with 12.
152  *
153  * The silent gateway 12 in the above may be the result of a bug in
154  * the 4.[23]BSD network code (and its derivatives):  4.x (x <= 3)
155  * sends an unreachable message using whatever ttl remains in the
156  * original datagram.  Since, for gateways, the remaining ttl is
157  * zero, the icmp "time exceeded" is guaranteed to not make it back
158  * to us.  The behavior of this bug is slightly more interesting
159  * when it appears on the destination system:
160  *
161  *      1  helios.ee.lbl.gov (128.3.112.1)  0 ms  0 ms  0 ms
162  *      2  lilac-dmc.Berkeley.EDU (128.32.216.1)  39 ms  19 ms  39 ms
163  *      3  lilac-dmc.Berkeley.EDU (128.32.216.1)  19 ms  39 ms  19 ms
164  *      4  ccngw-ner-cc.Berkeley.EDU (128.32.136.23)  39 ms  40 ms  19 ms
165  *      5  ccn-nerif35.Berkeley.EDU (128.32.168.35)  39 ms  39 ms  39 ms
166  *      6  csgw.Berkeley.EDU (128.32.133.254)  39 ms  59 ms  39 ms
167  *      7  * * *
168  *      8  * * *
169  *      9  * * *
170  *     10  * * *
171  *     11  * * *
172  *     12  * * *
173  *     13  rip.Berkeley.EDU (128.32.131.22)  59 ms !  39 ms !  39 ms !
174  *
175  * Notice that there are 12 "gateways" (13 is the final
176  * destination) and exactly the last half of them are "missing".
177  * What's really happening is that rip (a Sun-3 running Sun OS3.5)
178  * is using the ttl from our arriving datagram as the ttl in its
179  * icmp reply.  So, the reply will time out on the return path
180  * (with no notice sent to anyone since icmp's aren't sent for
181  * icmp's) until we probe with a ttl that's at least twice the path
182  * length.  I.e., rip is really only 7 hops away.  A reply that
183  * returns with a ttl of 1 is a clue this problem exists.
184  * Traceroute prints a "!" after the time if the ttl is <= 1.
185  * Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or
186  * non-standard (HPUX) software, expect to see this problem
187  * frequently and/or take care picking the target host of your
188  * probes.
189  *
190  * Other possible annotations after the time are !H, !N, !P (got a host,
191  * network or protocol unreachable, respectively), !S or !F (source
192  * route failed or fragmentation needed -- neither of these should
193  * ever occur and the associated gateway is busted if you see one).  If
194  * almost all the probes result in some kind of unreachable, traceroute
195  * will give up and exit.
196  *
197  * Notes
198  * -----
199  * This program must be run by root or be setuid.  (I suggest that
200  * you *don't* make it setuid -- casual use could result in a lot
201  * of unnecessary traffic on our poor, congested nets.)
202  *
203  * This program requires a kernel mod that does not appear in any
204  * system available from Berkeley:  A raw ip socket using proto
205  * IPPROTO_RAW must interpret the data sent as an ip datagram (as
206  * opposed to data to be wrapped in an ip datagram).  See the README
207  * file that came with the source to this program for a description
208  * of the mods I made to /sys/netinet/raw_ip.c.  Your mileage may
209  * vary.  But, again, ANY 4.x (x < 4) BSD KERNEL WILL HAVE TO BE
210  * MODIFIED TO RUN THIS PROGRAM.
211  *
212  * The udp port usage may appear bizarre (well, ok, it is bizarre).
213  * The problem is that an icmp message only contains 8 bytes of
214  * data from the original datagram.  8 bytes is the size of a udp
215  * header so, if we want to associate replies with the original
216  * datagram, the necessary information must be encoded into the
217  * udp header (the ip id could be used but there's no way to
218  * interlock with the kernel's assignment of ip id's and, anyway,
219  * it would have taken a lot more kernel hacking to allow this
220  * code to set the ip id).  So, to allow two or more users to
221  * use traceroute simultaneously, we use this task's pid as the
222  * source port (the high bit is set to move the port number out
223  * of the "likely" range).  To keep track of which probe is being
224  * replied to (so times and/or hop counts don't get confused by a
225  * reply that was delayed in transit), we increment the destination
226  * port number before each probe.
227  *
228  * Don't use this as a coding example.  I was trying to find a
229  * routing problem and this code sort-of popped out after 48 hours
230  * without sleep.  I was amazed it ever compiled, much less ran.
231  *
232  * I stole the idea for this program from Steve Deering.  Since
233  * the first release, I've learned that had I attended the right
234  * IETF working group meetings, I also could have stolen it from Guy
235  * Almes or Matt Mathis.  I don't know (or care) who came up with
236  * the idea first.  I envy the originators' perspicacity and I'm
237  * glad they didn't keep the idea a secret.
238  *
239  * Tim Seaver, Ken Adelman and C. Philip Wood provided bug fixes and/or
240  * enhancements to the original distribution.
241  *
242  * I've hacked up a round-trip-route version of this that works by
243  * sending a loose-source-routed udp datagram through the destination
244  * back to yourself.  Unfortunately, SO many gateways botch source
245  * routing, the thing is almost worthless.  Maybe one day...
246  *
247  *  -- Van Jacobson (van@helios.ee.lbl.gov)
248  *     Tue Dec 20 03:50:13 PST 1988
249  */
250 
251 #include <sys/param.h>
252 #include <sys/capsicum.h>
253 #include <sys/time.h>
254 #include <sys/socket.h>
255 #include <sys/uio.h>
256 #include <sys/file.h>
257 #include <sys/ioctl.h>
258 #include <sys/sysctl.h>
259 
260 #include <netinet/in.h>
261 
262 #include <arpa/inet.h>
263 
264 #include <libcasper.h>
265 #include <casper/cap_dns.h>
266 #include <capsicum_helpers.h>
267 
268 #include <netdb.h>
269 #include <stdio.h>
270 #include <err.h>
271 #ifdef HAVE_POLL
272 #include <poll.h>
273 #endif
274 #include <errno.h>
275 #include <stdlib.h>
276 #include <string.h>
277 #include <unistd.h>
278 
279 #include <netinet/ip6.h>
280 #include <netinet/icmp6.h>
281 #include <netinet/sctp.h>
282 #include <netinet/sctp_header.h>
283 #include <netinet/tcp.h>
284 #include <netinet/udp.h>
285 
286 #ifdef IPSEC
287 #include <net/route.h>
288 #include <netipsec/ipsec.h>
289 #endif
290 
291 #include "as.h"
292 
293 #define DUMMY_PORT 10010
294 
295 #define	MAXPACKET	65535	/* max ip packet size */
296 
297 static u_char	packet[512];		/* last inbound (icmp) packet */
298 static char 	*outpacket;		/* last output packet */
299 
300 int	main(int, char *[]);
301 int	wait_for_reply(int, struct msghdr *);
302 #if defined(IPSEC) && defined(IPSEC_POLICY_IPSEC)
303 int	setpolicy(int so, char *policy);
304 #endif
305 void	send_probe(int, u_long);
306 void	*get_uphdr(struct ip6_hdr *, u_char *);
307 void	capdns_open(void);
308 int	get_hoplim(struct msghdr *);
309 double	deltaT(struct timeval *, struct timeval *);
310 const char *pr_type(int);
311 int	packet_ok(struct msghdr *, int, int, u_char *, u_char *);
312 void	print(struct msghdr *, int);
313 const char *inetname(struct sockaddr *);
314 u_int32_t sctp_crc32c(void *, u_int32_t);
315 u_int16_t in_cksum(u_int16_t *addr, int);
316 u_int16_t udp_cksum(struct sockaddr_in6 *, struct sockaddr_in6 *,
317     void *, u_int32_t);
318 u_int16_t tcp_chksum(struct sockaddr_in6 *, struct sockaddr_in6 *,
319     void *, u_int32_t);
320 void	usage(void);
321 
322 static int rcvsock;			/* receive (icmp) socket file descriptor */
323 static int sndsock;			/* send (raw/udp) socket file descriptor */
324 
325 static struct msghdr rcvmhdr;
326 static struct iovec rcviov[2];
327 static int rcvhlim;
328 static struct in6_pktinfo *rcvpktinfo;
329 
330 static struct sockaddr_in6 Src, Dst, Rcv;
331 static u_long datalen = 20;			/* How much data */
332 #define	ICMP6ECHOLEN	8
333 /* XXX: 2064 = 127(max hops in type 0 rthdr) * sizeof(ip6_hdr) + 16(margin) */
334 static char rtbuf[2064];
335 static struct ip6_rthdr *rth;
336 static struct cmsghdr *cmsg;
337 
338 static char *source = NULL;
339 static char *hostname;
340 
341 static cap_channel_t *capdns;
342 
343 static u_long nprobes = 3;
344 static u_long first_hop = 1;
345 static u_long max_hops = 30;
346 static u_int16_t srcport;
347 static u_int16_t port = 32768+666;	/* start udp dest port # for probe packets */
348 static u_int16_t ident;
349 static int tclass = -1;
350 static int options;			/* socket options */
351 static int verbose;
352 static int waittime = 5;		/* time to wait for response (in seconds) */
353 static int nflag;			/* print addresses numerically */
354 static int useproto = IPPROTO_UDP;	/* protocol to use to send packet */
355 static int lflag;			/* print both numerical address & hostname */
356 static int as_path;			/* print as numbers for each hop */
357 static char *as_server = NULL;
358 static void *asn;
359 
360 int
361 main(int argc, char *argv[])
362 {
363 	int mib[4] = { CTL_NET, PF_INET6, IPPROTO_IPV6, IPV6CTL_DEFHLIM };
364 	char hbuf[NI_MAXHOST], src0[NI_MAXHOST], *ep;
365 	int ch, i, on = 1, seq, rcvcmsglen, error;
366 	struct addrinfo hints, *res;
367 	static u_char *rcvcmsgbuf;
368 	u_long probe, hops, lport, ltclass;
369 	struct hostent *hp;
370 	size_t size, minlen;
371 	uid_t uid;
372 	u_char type, code;
373 #if defined(IPSEC) && defined(IPSEC_POLICY_IPSEC)
374 	char ipsec_inpolicy[] = "in bypass";
375 	char ipsec_outpolicy[] = "out bypass";
376 #endif
377 	cap_rights_t rights;
378 
379 	capdns_open();
380 
381 	/*
382 	 * Receive ICMP
383 	 */
384 	if ((rcvsock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0) {
385 		perror("socket(ICMPv6)");
386 		exit(5);
387 	}
388 
389 	size = sizeof(i);
390 	(void) sysctl(mib, sizeof(mib)/sizeof(mib[0]), &i, &size, NULL, 0);
391 	max_hops = i;
392 
393 	/* specify to tell receiving interface */
394 #ifdef IPV6_RECVPKTINFO
395 	if (setsockopt(rcvsock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
396 	    sizeof(on)) < 0)
397 		err(1, "setsockopt(IPV6_RECVPKTINFO)");
398 #else  /* old adv. API */
399 	if (setsockopt(rcvsock, IPPROTO_IPV6, IPV6_PKTINFO, &on,
400 	    sizeof(on)) < 0)
401 		err(1, "setsockopt(IPV6_PKTINFO)");
402 #endif
403 
404 	/* specify to tell value of hoplimit field of received IP6 hdr */
405 #ifdef IPV6_RECVHOPLIMIT
406 	if (setsockopt(rcvsock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on,
407 	    sizeof(on)) < 0)
408 		err(1, "setsockopt(IPV6_RECVHOPLIMIT)");
409 #else  /* old adv. API */
410 	if (setsockopt(rcvsock, IPPROTO_IPV6, IPV6_HOPLIMIT, &on,
411 	    sizeof(on)) < 0)
412 		err(1, "setsockopt(IPV6_HOPLIMIT)");
413 #endif
414 
415 	seq = 0;
416 	ident = htons(getpid() & 0xffff); /* same as ping6 */
417 
418 	while ((ch = getopt(argc, argv, "aA:df:g:Ilm:nNp:q:rs:St:TUvw:")) != -1)
419 		switch (ch) {
420 		case 'a':
421 			as_path = 1;
422 			break;
423 		case 'A':
424 			as_path = 1;
425 			as_server = optarg;
426 			break;
427 		case 'd':
428 			options |= SO_DEBUG;
429 			break;
430 		case 'f':
431 			ep = NULL;
432 			errno = 0;
433 			first_hop = strtoul(optarg, &ep, 0);
434 			if (errno || !*optarg || *ep || first_hop > 255) {
435 				fprintf(stderr,
436 				    "traceroute6: invalid min hoplimit.\n");
437 				exit(1);
438 			}
439 			break;
440 		case 'g':
441 			/* XXX use after capability mode is entered */
442 			hp = getipnodebyname(optarg, AF_INET6, 0, &h_errno);
443 			if (hp == NULL) {
444 				fprintf(stderr,
445 				    "traceroute6: unknown host %s\n", optarg);
446 				exit(1);
447 			}
448 			if (rth == NULL) {
449 				/*
450 				 * XXX: We can't detect the number of
451 				 * intermediate nodes yet.
452 				 */
453 				if ((rth = inet6_rth_init((void *)rtbuf,
454 				    sizeof(rtbuf), IPV6_RTHDR_TYPE_0,
455 				    0)) == NULL) {
456 					fprintf(stderr,
457 					    "inet6_rth_init failed.\n");
458 					exit(1);
459 				}
460 			}
461 			if (inet6_rth_add((void *)rth,
462 			    (struct in6_addr *)hp->h_addr)) {
463 				fprintf(stderr,
464 				    "inet6_rth_add failed for %s\n",
465 				    optarg);
466 				exit(1);
467 			}
468 			freehostent(hp);
469 			break;
470 		case 'I':
471 			useproto = IPPROTO_ICMPV6;
472 			break;
473 		case 'l':
474 			lflag++;
475 			break;
476 		case 'm':
477 			ep = NULL;
478 			errno = 0;
479 			max_hops = strtoul(optarg, &ep, 0);
480 			if (errno || !*optarg || *ep || max_hops > 255) {
481 				fprintf(stderr,
482 				    "traceroute6: invalid max hoplimit.\n");
483 				exit(1);
484 			}
485 			break;
486 		case 'n':
487 			nflag++;
488 			break;
489 		case 'N':
490 			useproto = IPPROTO_NONE;
491 			break;
492 		case 'p':
493 			ep = NULL;
494 			errno = 0;
495 			lport = strtoul(optarg, &ep, 0);
496 			if (errno || !*optarg || *ep) {
497 				fprintf(stderr, "traceroute6: invalid port.\n");
498 				exit(1);
499 			}
500 			if (lport == 0 || lport != (lport & 0xffff)) {
501 				fprintf(stderr,
502 				    "traceroute6: port out of range.\n");
503 				exit(1);
504 			}
505 			port = lport & 0xffff;
506 			break;
507 		case 'q':
508 			ep = NULL;
509 			errno = 0;
510 			nprobes = strtoul(optarg, &ep, 0);
511 			if (errno || !*optarg || *ep) {
512 				fprintf(stderr,
513 				    "traceroute6: invalid nprobes.\n");
514 				exit(1);
515 			}
516 			if (nprobes < 1) {
517 				fprintf(stderr,
518 				    "traceroute6: nprobes must be >0.\n");
519 				exit(1);
520 			}
521 			break;
522 		case 'r':
523 			options |= SO_DONTROUTE;
524 			break;
525 		case 's':
526 			/*
527 			 * set the ip source address of the outbound
528 			 * probe (e.g., on a multi-homed host).
529 			 */
530 			source = optarg;
531 			break;
532 		case 'S':
533 			useproto = IPPROTO_SCTP;
534 			break;
535 		case 't':
536 			ep = NULL;
537 			errno = 0;
538 			ltclass = strtoul(optarg, &ep, 0);
539 			if (errno || !*optarg || *ep || ltclass > 255) {
540 				fprintf(stderr,
541 				    "traceroute6: invalid traffic class.\n");
542 				exit(1);
543 			}
544 			tclass = (int)ltclass;
545 			break;
546 		case 'T':
547 			useproto = IPPROTO_TCP;
548 			break;
549 		case 'U':
550 			useproto = IPPROTO_UDP;
551 			break;
552 		case 'v':
553 			verbose++;
554 			break;
555 		case 'w':
556 			ep = NULL;
557 			errno = 0;
558 			waittime = strtoul(optarg, &ep, 0);
559 			if (errno || !*optarg || *ep) {
560 				fprintf(stderr,
561 				    "traceroute6: invalid wait time.\n");
562 				exit(1);
563 			}
564 			if (waittime < 1) {
565 				fprintf(stderr,
566 				    "traceroute6: wait must be >= 1 sec.\n");
567 				exit(1);
568 			}
569 			break;
570 		default:
571 			usage();
572 		}
573 	argc -= optind;
574 	argv += optind;
575 
576 	/*
577 	 * Open socket to send probe packets.
578 	 */
579 	switch (useproto) {
580 	case IPPROTO_ICMPV6:
581 	case IPPROTO_NONE:
582 	case IPPROTO_SCTP:
583 	case IPPROTO_TCP:
584 	case IPPROTO_UDP:
585 		if ((sndsock = socket(AF_INET6, SOCK_RAW, useproto)) < 0) {
586 			perror("socket(SOCK_RAW)");
587 			exit(5);
588 		}
589 		break;
590 	default:
591 		fprintf(stderr, "traceroute6: unknown probe protocol %d\n",
592 		    useproto);
593 		exit(5);
594 	}
595 	if (max_hops < first_hop) {
596 		fprintf(stderr,
597 		    "traceroute6: max hoplimit must be larger than first hoplimit.\n");
598 		exit(1);
599 	}
600 
601 	/* revoke privs */
602 	uid = getuid();
603 	if (setresuid(uid, uid, uid) == -1) {
604 		perror("setresuid");
605 		exit(1);
606 	}
607 
608 	if (tclass != -1) {
609 		if (setsockopt(sndsock, IPPROTO_IPV6, IPV6_TCLASS, &tclass,
610 		    sizeof(int)) == -1) {
611 			perror("setsockopt(IPV6_TCLASS)");
612 			exit(7);
613 		}
614 	}
615 
616 	if (argc < 1 || argc > 2)
617 		usage();
618 
619 #if 1
620 	setvbuf(stdout, NULL, _IOLBF, BUFSIZ);
621 #else
622 	setlinebuf(stdout);
623 #endif
624 
625 	memset(&hints, 0, sizeof(hints));
626 	hints.ai_family = PF_INET6;
627 	hints.ai_socktype = SOCK_RAW;
628 	hints.ai_protocol = IPPROTO_ICMPV6;
629 	hints.ai_flags = AI_CANONNAME;
630 
631 	error = cap_getaddrinfo(capdns, *argv, NULL, &hints, &res);
632 
633 	if (error) {
634 		fprintf(stderr,
635 		    "traceroute6: %s\n", gai_strerror(error));
636 		exit(1);
637 	}
638 	if (res->ai_addrlen != sizeof(Dst)) {
639 		fprintf(stderr,
640 		    "traceroute6: size of sockaddr mismatch\n");
641 		exit(1);
642 	}
643 	memcpy(&Dst, res->ai_addr, res->ai_addrlen);
644 	hostname = res->ai_canonname ? strdup(res->ai_canonname) : *argv;
645 	if (!hostname) {
646 		fprintf(stderr, "traceroute6: not enough core\n");
647 		exit(1);
648 	}
649 	if (res->ai_next) {
650 		if (cap_getnameinfo(capdns, res->ai_addr, res->ai_addrlen, hbuf,
651 		    sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0)
652 			strlcpy(hbuf, "?", sizeof(hbuf));
653 		fprintf(stderr, "traceroute6: Warning: %s has multiple "
654 		    "addresses; using %s\n", hostname, hbuf);
655 	}
656 	freeaddrinfo(res);
657 	if (*++argv) {
658 		ep = NULL;
659 		errno = 0;
660 		datalen = strtoul(*argv, &ep, 0);
661 		if (errno || *ep) {
662 			fprintf(stderr,
663 			    "traceroute6: invalid packet length.\n");
664 			exit(1);
665 		}
666 	}
667 	switch (useproto) {
668 	case IPPROTO_ICMPV6:
669 		minlen = ICMP6ECHOLEN;
670 		break;
671 	case IPPROTO_UDP:
672 		minlen = sizeof(struct udphdr);
673 		break;
674 	case IPPROTO_NONE:
675 		minlen = 0;
676 		datalen = 0;
677 		break;
678 	case IPPROTO_SCTP:
679 		minlen = sizeof(struct sctphdr);
680 		break;
681 	case IPPROTO_TCP:
682 		minlen = sizeof(struct tcphdr);
683 		break;
684 	default:
685 		fprintf(stderr, "traceroute6: unknown probe protocol %d.\n",
686 		    useproto);
687 		exit(1);
688 	}
689 	if (datalen < minlen)
690 		datalen = minlen;
691 	else if (datalen >= MAXPACKET) {
692 		fprintf(stderr,
693 		    "traceroute6: packet size must be %zu <= s < %d.\n",
694 		    minlen, MAXPACKET);
695 		exit(1);
696 	}
697 	if ((useproto == IPPROTO_SCTP) && (datalen & 3)) {
698 		fprintf(stderr,
699 		    "traceroute6: packet size must be a multiple of 4.\n");
700 		exit(1);
701 	}
702 	outpacket = malloc(datalen);
703 	if (!outpacket) {
704 		perror("malloc");
705 		exit(1);
706 	}
707 	(void) bzero((char *)outpacket, datalen);
708 
709 	/* initialize msghdr for receiving packets */
710 	rcviov[0].iov_base = (caddr_t)packet;
711 	rcviov[0].iov_len = sizeof(packet);
712 	rcvmhdr.msg_name = (caddr_t)&Rcv;
713 	rcvmhdr.msg_namelen = sizeof(Rcv);
714 	rcvmhdr.msg_iov = rcviov;
715 	rcvmhdr.msg_iovlen = 1;
716 	rcvcmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
717 	    CMSG_SPACE(sizeof(int));
718 	if ((rcvcmsgbuf = malloc(rcvcmsglen)) == NULL) {
719 		fprintf(stderr, "traceroute6: malloc failed\n");
720 		exit(1);
721 	}
722 	rcvmhdr.msg_control = (caddr_t) rcvcmsgbuf;
723 	rcvmhdr.msg_controllen = rcvcmsglen;
724 
725 	if (options & SO_DEBUG)
726 		(void) setsockopt(rcvsock, SOL_SOCKET, SO_DEBUG,
727 		    (char *)&on, sizeof(on));
728 	if (options & SO_DONTROUTE)
729 		(void) setsockopt(rcvsock, SOL_SOCKET, SO_DONTROUTE,
730 		    (char *)&on, sizeof(on));
731 #if defined(IPSEC) && defined(IPSEC_POLICY_IPSEC)
732 	/*
733 	 * do not raise error even if setsockopt fails, kernel may have ipsec
734 	 * turned off.
735 	 */
736 	if (setpolicy(rcvsock, ipsec_inpolicy) < 0)
737 		errx(1, "%s", ipsec_strerror());
738 	if (setpolicy(rcvsock, ipsec_outpolicy) < 0)
739 		errx(1, "%s", ipsec_strerror());
740 #else
741     {
742 	int level = IPSEC_LEVEL_NONE;
743 
744 	(void)setsockopt(rcvsock, IPPROTO_IPV6, IPV6_ESP_TRANS_LEVEL, &level,
745 	    sizeof(level));
746 	(void)setsockopt(rcvsock, IPPROTO_IPV6, IPV6_ESP_NETWORK_LEVEL, &level,
747 	    sizeof(level));
748 #ifdef IP_AUTH_TRANS_LEVEL
749 	(void)setsockopt(rcvsock, IPPROTO_IPV6, IPV6_AUTH_TRANS_LEVEL, &level,
750 	    sizeof(level));
751 #else
752 	(void)setsockopt(rcvsock, IPPROTO_IPV6, IPV6_AUTH_LEVEL, &level,
753 	    sizeof(level));
754 #endif
755 #ifdef IP_AUTH_NETWORK_LEVEL
756 	(void)setsockopt(rcvsock, IPPROTO_IPV6, IPV6_AUTH_NETWORK_LEVEL, &level,
757 	    sizeof(level));
758 #endif
759     }
760 #endif /* !(IPSEC && IPSEC_POLICY_IPSEC) */
761 
762 #ifdef SO_SNDBUF
763 	i = datalen;
764 	if (i == 0)
765 		i = 1;
766 	if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, (char *)&i,
767 	    sizeof(i)) < 0) {
768 		perror("setsockopt(SO_SNDBUF)");
769 		exit(6);
770 	}
771 #endif /* SO_SNDBUF */
772 	if (options & SO_DEBUG)
773 		(void) setsockopt(sndsock, SOL_SOCKET, SO_DEBUG,
774 		    (char *)&on, sizeof(on));
775 	if (options & SO_DONTROUTE)
776 		(void) setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE,
777 		    (char *)&on, sizeof(on));
778 	if (rth) {/* XXX: there is no library to finalize the header... */
779 		rth->ip6r_len = rth->ip6r_segleft * 2;
780 		if (setsockopt(sndsock, IPPROTO_IPV6, IPV6_RTHDR,
781 		    (void *)rth, (rth->ip6r_len + 1) << 3)) {
782 			fprintf(stderr, "setsockopt(IPV6_RTHDR): %s\n",
783 			    strerror(errno));
784 			exit(1);
785 		}
786 	}
787 #if defined(IPSEC) && defined(IPSEC_POLICY_IPSEC)
788 	/*
789 	 * do not raise error even if setsockopt fails, kernel may have ipsec
790 	 * turned off.
791 	 */
792 	if (setpolicy(sndsock, ipsec_inpolicy) < 0)
793 		errx(1, "%s", ipsec_strerror());
794 	if (setpolicy(sndsock, ipsec_outpolicy) < 0)
795 		errx(1, "%s", ipsec_strerror());
796 #else
797     {
798 	int level = IPSEC_LEVEL_BYPASS;
799 
800 	(void)setsockopt(sndsock, IPPROTO_IPV6, IPV6_ESP_TRANS_LEVEL, &level,
801 	    sizeof(level));
802 	(void)setsockopt(sndsock, IPPROTO_IPV6, IPV6_ESP_NETWORK_LEVEL, &level,
803 	    sizeof(level));
804 #ifdef IP_AUTH_TRANS_LEVEL
805 	(void)setsockopt(sndsock, IPPROTO_IPV6, IPV6_AUTH_TRANS_LEVEL, &level,
806 	    sizeof(level));
807 #else
808 	(void)setsockopt(sndsock, IPPROTO_IPV6, IPV6_AUTH_LEVEL, &level,
809 	    sizeof(level));
810 #endif
811 #ifdef IP_AUTH_NETWORK_LEVEL
812 	(void)setsockopt(sndsock, IPPROTO_IPV6, IPV6_AUTH_NETWORK_LEVEL, &level,
813 	    sizeof(level));
814 #endif
815     }
816 #endif /* !(IPSEC && IPSEC_POLICY_IPSEC) */
817 
818 	/*
819 	 * Source selection
820 	 */
821 	bzero(&Src, sizeof(Src));
822 	if (source) {
823 		memset(&hints, 0, sizeof(hints));
824 		hints.ai_family = AF_INET6;
825 		hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
826 		hints.ai_flags = AI_NUMERICHOST;
827 		error = cap_getaddrinfo(capdns, source, "0", &hints, &res);
828 		if (error) {
829 			printf("traceroute6: %s: %s\n", source,
830 			    gai_strerror(error));
831 			exit(1);
832 		}
833 		if (res->ai_addrlen > sizeof(Src)) {
834 			printf("traceroute6: %s: %s\n", source,
835 			    gai_strerror(error));
836 			exit(1);
837 		}
838 		memcpy(&Src, res->ai_addr, res->ai_addrlen);
839 		freeaddrinfo(res);
840 	} else {
841 		struct sockaddr_in6 Nxt;
842 		int dummy;
843 		socklen_t len;
844 
845 		Nxt = Dst;
846 		Nxt.sin6_port = htons(DUMMY_PORT);
847 		if (cmsg != NULL)
848 			bcopy(inet6_rthdr_getaddr(cmsg, 1), &Nxt.sin6_addr,
849 			    sizeof(Nxt.sin6_addr));
850 		if ((dummy = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
851 			perror("socket");
852 			exit(1);
853 		}
854 		if (connect(dummy, (struct sockaddr *)&Nxt, Nxt.sin6_len) < 0) {
855 			perror("connect");
856 			exit(1);
857 		}
858 		len = sizeof(Src);
859 		if (getsockname(dummy, (struct sockaddr *)&Src, &len) < 0) {
860 			perror("getsockname");
861 			exit(1);
862 		}
863 		if (cap_getnameinfo(capdns, (struct sockaddr *)&Src, Src.sin6_len,
864 		    src0, sizeof(src0), NULL, 0, NI_NUMERICHOST)) {
865 			fprintf(stderr, "getnameinfo failed for source\n");
866 			exit(1);
867 		}
868 		source = src0;
869 		close(dummy);
870 	}
871 
872 	Src.sin6_port = htons(0);
873 	if (bind(sndsock, (struct sockaddr *)&Src, Src.sin6_len) < 0) {
874 		perror("bind");
875 		exit(1);
876 	}
877 
878 	{
879 		socklen_t len;
880 
881 		len = sizeof(Src);
882 		if (getsockname(sndsock, (struct sockaddr *)&Src, &len) < 0) {
883 			perror("getsockname");
884 			exit(1);
885 		}
886 		srcport = ntohs(Src.sin6_port);
887 	}
888 
889 	if (as_path) {
890 		asn = as_setup(as_server);
891 		if (asn == NULL) {
892 			fprintf(stderr,
893 			    "traceroute6: as_setup failed, AS# lookups"
894 			    " disabled\n");
895 			(void)fflush(stderr);
896 			as_path = 0;
897 		}
898 	}
899 
900 	/*
901 	 * Message to users
902 	 */
903 	if (cap_getnameinfo(capdns, (struct sockaddr *)&Dst, Dst.sin6_len, hbuf,
904 	    sizeof(hbuf), NULL, 0, NI_NUMERICHOST))
905 		strlcpy(hbuf, "(invalid)", sizeof(hbuf));
906 	fprintf(stderr, "traceroute6");
907 	fprintf(stderr, " to %s (%s)", hostname, hbuf);
908 	if (source)
909 		fprintf(stderr, " from %s", source);
910 	fprintf(stderr, ", %lu hops max, %lu byte packets\n",
911 	    max_hops,
912 	    datalen + ((useproto == IPPROTO_UDP) ? sizeof(struct udphdr) : 0));
913 	(void) fflush(stderr);
914 
915 	if (first_hop > 1)
916 		printf("Skipping %lu intermediate hops\n", first_hop - 1);
917 
918 	if (connect(sndsock, (struct sockaddr *)&Dst,
919 	    sizeof(Dst)) != 0) {
920 		fprintf(stderr, "connect: %s\n", strerror(errno));
921 		exit(1);
922 	}
923 
924 	/*
925 	 * Here we enter capability mode. Further down access to global
926 	 * namespaces (e.g filesystem) is restricted (see capsicum(4)).
927 	 * We must connect(2) our socket before this point.
928 	 */
929 	if (caph_enter_casper() < 0) {
930 		fprintf(stderr, "caph_enter_casper: %s\n", strerror(errno));
931 		exit(1);
932 	}
933 
934 	cap_rights_init(&rights, CAP_SEND, CAP_SETSOCKOPT);
935 	if (caph_rights_limit(sndsock, &rights) < 0) {
936 		fprintf(stderr, "caph_rights_limit sndsock: %s\n",
937 		    strerror(errno));
938 		exit(1);
939 	}
940 	cap_rights_init(&rights, CAP_RECV, CAP_EVENT);
941 	if (caph_rights_limit(rcvsock, &rights) < 0) {
942 		fprintf(stderr, "caph_rights_limit rcvsock: %s\n",
943 		    strerror(errno));
944 		exit(1);
945 	}
946 
947 	/*
948 	 * Main loop
949 	 */
950 	for (hops = first_hop; hops <= max_hops; ++hops) {
951 		struct in6_addr lastaddr;
952 		int got_there = 0;
953 		unsigned unreachable = 0;
954 
955 		printf("%2lu ", hops);
956 		bzero(&lastaddr, sizeof(lastaddr));
957 		for (probe = 0; probe < nprobes; ++probe) {
958 			int cc;
959 			struct timeval t1, t2;
960 
961 			(void) gettimeofday(&t1, NULL);
962 			send_probe(++seq, hops);
963 			while ((cc = wait_for_reply(rcvsock, &rcvmhdr))) {
964 				(void) gettimeofday(&t2, NULL);
965 				if (packet_ok(&rcvmhdr, cc, seq, &type, &code)) {
966 					if (!IN6_ARE_ADDR_EQUAL(&Rcv.sin6_addr,
967 					    &lastaddr)) {
968 						if (probe > 0)
969 							fputs("\n   ", stdout);
970 						print(&rcvmhdr, cc);
971 						lastaddr = Rcv.sin6_addr;
972 					}
973 					printf("  %.3f ms", deltaT(&t1, &t2));
974 					if (type == ICMP6_DST_UNREACH) {
975 						switch (code) {
976 						case ICMP6_DST_UNREACH_NOROUTE:
977 							++unreachable;
978 							printf(" !N");
979 							break;
980 						case ICMP6_DST_UNREACH_ADMIN:
981 							++unreachable;
982 							printf(" !P");
983 							break;
984 						case ICMP6_DST_UNREACH_NOTNEIGHBOR:
985 							++unreachable;
986 							printf(" !S");
987 							break;
988 						case ICMP6_DST_UNREACH_ADDR:
989 							++unreachable;
990 							printf(" !A");
991 							break;
992 						case ICMP6_DST_UNREACH_NOPORT:
993 							if (rcvhlim >= 0 &&
994 							    rcvhlim <= 1)
995 								printf(" !");
996 							++got_there;
997 							break;
998 						}
999 					} else if (type == ICMP6_PARAM_PROB &&
1000 					    code == ICMP6_PARAMPROB_NEXTHEADER) {
1001 						printf(" !H");
1002 						++got_there;
1003 					} else if (type == ICMP6_ECHO_REPLY) {
1004 						if (rcvhlim >= 0 &&
1005 						    rcvhlim <= 1)
1006 							printf(" !");
1007 						++got_there;
1008 					}
1009 					break;
1010 				} else if (deltaT(&t1, &t2) > waittime * 1000) {
1011 					cc = 0;
1012 					break;
1013 				}
1014 			}
1015 			if (cc == 0)
1016 				printf(" *");
1017 			(void) fflush(stdout);
1018 		}
1019 		putchar('\n');
1020 		if (got_there ||
1021 		    (unreachable > 0 && unreachable >= ((nprobes + 1) / 2))) {
1022 			exit(0);
1023 		}
1024 	}
1025 	if (as_path)
1026 		as_shutdown(asn);
1027 
1028 	exit(0);
1029 }
1030 
1031 int
1032 wait_for_reply(int sock, struct msghdr *mhdr)
1033 {
1034 #ifdef HAVE_POLL
1035 	struct pollfd pfd[1];
1036 	int cc = 0;
1037 
1038 	pfd[0].fd = sock;
1039 	pfd[0].events = POLLIN;
1040 	pfd[0].revents = 0;
1041 
1042 	if (poll(pfd, 1, waittime * 1000) > 0 &&
1043 	    pfd[0].revents & POLLIN)
1044 		cc = recvmsg(rcvsock, mhdr, 0);
1045 
1046 	return (cc);
1047 #else
1048 	fd_set *fdsp;
1049 	struct timeval wait;
1050 	int cc = 0, fdsn;
1051 
1052 	fdsn = howmany(sock + 1, NFDBITS) * sizeof(fd_mask);
1053 	if ((fdsp = (fd_set *)malloc(fdsn)) == NULL)
1054 		err(1, "malloc");
1055 	memset(fdsp, 0, fdsn);
1056 	FD_SET(sock, fdsp);
1057 	wait.tv_sec = waittime; wait.tv_usec = 0;
1058 
1059 	if (select(sock+1, fdsp, (fd_set *)0, (fd_set *)0, &wait) > 0)
1060 		cc = recvmsg(rcvsock, mhdr, 0);
1061 
1062 	free(fdsp);
1063 	return (cc);
1064 #endif
1065 }
1066 
1067 #if defined(IPSEC) && defined(IPSEC_POLICY_IPSEC)
1068 int
1069 setpolicy(int so, char *policy)
1070 {
1071 	char *buf;
1072 
1073 	buf = ipsec_set_policy(policy, strlen(policy));
1074 	if (buf == NULL) {
1075 		warnx("%s", ipsec_strerror());
1076 		return -1;
1077 	}
1078 	(void)setsockopt(so, IPPROTO_IPV6, IPV6_IPSEC_POLICY,
1079 	    buf, ipsec_get_policylen(buf));
1080 
1081 	free(buf);
1082 
1083 	return 0;
1084 }
1085 #endif
1086 
1087 void
1088 send_probe(int seq, u_long hops)
1089 {
1090 	struct icmp6_hdr *icp;
1091 	struct sctphdr *sctp;
1092 	struct udphdr *outudp;
1093 	struct sctp_chunkhdr *chk;
1094 	struct sctp_init_chunk *init;
1095 	struct sctp_paramhdr *param;
1096 	struct tcphdr *tcp;
1097 	int i;
1098 
1099 	i = hops;
1100 	if (setsockopt(sndsock, IPPROTO_IPV6, IPV6_UNICAST_HOPS,
1101 	    (char *)&i, sizeof(i)) < 0) {
1102 		perror("setsockopt IPV6_UNICAST_HOPS");
1103 	}
1104 
1105 	Dst.sin6_port = htons(port + seq);
1106 
1107 	switch (useproto) {
1108 	case IPPROTO_ICMPV6:
1109 		icp = (struct icmp6_hdr *)outpacket;
1110 
1111 		icp->icmp6_type = ICMP6_ECHO_REQUEST;
1112 		icp->icmp6_code = 0;
1113 		icp->icmp6_cksum = 0;
1114 		icp->icmp6_id = ident;
1115 		icp->icmp6_seq = htons(seq);
1116 		break;
1117 	case IPPROTO_UDP:
1118 		outudp = (struct udphdr *) outpacket;
1119 		outudp->uh_sport = htons(ident);
1120 		outudp->uh_dport = htons(port+seq);
1121 		outudp->uh_ulen = htons(datalen);
1122 		outudp->uh_sum = 0;
1123 		outudp->uh_sum = udp_cksum(&Src, &Dst, outpacket, datalen);
1124 		break;
1125 	case IPPROTO_NONE:
1126 		/* No space for anything. No harm as seq/tv32 are decorative. */
1127 		break;
1128 	case IPPROTO_SCTP:
1129 		sctp = (struct sctphdr *)outpacket;
1130 
1131 		sctp->src_port = htons(ident);
1132 		sctp->dest_port = htons(port + seq);
1133 		if (datalen >= (u_long)(sizeof(struct sctphdr) +
1134 		    sizeof(struct sctp_init_chunk))) {
1135 			sctp->v_tag = 0;
1136 		} else {
1137 			sctp->v_tag = (sctp->src_port << 16) | sctp->dest_port;
1138 		}
1139 		sctp->checksum = htonl(0);
1140 		if (datalen >= (u_long)(sizeof(struct sctphdr) +
1141 		    sizeof(struct sctp_init_chunk))) {
1142 			/*
1143 			 * Send a packet containing an INIT chunk. This works
1144 			 * better in case of firewalls on the path, but
1145 			 * results in a probe packet containing at least
1146 			 * 32 bytes of payload. For shorter payloads, use
1147 			 * SHUTDOWN-ACK chunks.
1148 			 */
1149 			init = (struct sctp_init_chunk *)(sctp + 1);
1150 			init->ch.chunk_type = SCTP_INITIATION;
1151 			init->ch.chunk_flags = 0;
1152 			init->ch.chunk_length = htons((u_int16_t)(datalen -
1153 			    sizeof(struct sctphdr)));
1154 			init->init.initiate_tag = (sctp->src_port << 16) |
1155 			    sctp->dest_port;
1156 			init->init.a_rwnd = htonl(1500);
1157 			init->init.num_outbound_streams = htons(1);
1158 			init->init.num_inbound_streams = htons(1);
1159 			init->init.initial_tsn = htonl(0);
1160 			if (datalen >= (u_long)(sizeof(struct sctphdr) +
1161 			    sizeof(struct sctp_init_chunk) +
1162 			    sizeof(struct sctp_paramhdr))) {
1163 				param = (struct sctp_paramhdr *)(init + 1);
1164 				param->param_type = htons(SCTP_PAD);
1165 				param->param_length =
1166 				    htons((u_int16_t)(datalen -
1167 				    sizeof(struct sctphdr) -
1168 				    sizeof(struct sctp_init_chunk)));
1169 			}
1170 		} else {
1171 			/*
1172 			 * Send a packet containing a SHUTDOWN-ACK chunk,
1173 			 * possibly followed by a PAD chunk.
1174 			 */
1175 			if (datalen >= (u_long)(sizeof(struct sctphdr) +
1176 			    sizeof(struct sctp_chunkhdr))) {
1177 				chk = (struct sctp_chunkhdr *)(sctp + 1);
1178 				chk->chunk_type = SCTP_SHUTDOWN_ACK;
1179 				chk->chunk_flags = 0;
1180 				chk->chunk_length = htons(4);
1181 			}
1182 			if (datalen >= (u_long)(sizeof(struct sctphdr) +
1183 			    2 * sizeof(struct sctp_chunkhdr))) {
1184 				chk = chk + 1;
1185 				chk->chunk_type = SCTP_PAD_CHUNK;
1186 				chk->chunk_flags = 0;
1187 				chk->chunk_length = htons((u_int16_t)(datalen -
1188 				    sizeof(struct sctphdr) -
1189 				    sizeof(struct sctp_chunkhdr)));
1190 			}
1191 		}
1192 		sctp->checksum = sctp_crc32c(outpacket, datalen);
1193 		break;
1194 	case IPPROTO_TCP:
1195 		tcp = (struct tcphdr *)outpacket;
1196 
1197 		tcp->th_sport = htons(ident);
1198 		tcp->th_dport = htons(port + seq);
1199 		tcp->th_seq = (tcp->th_sport << 16) | tcp->th_dport;
1200 		tcp->th_ack = 0;
1201 		tcp->th_off = 5;
1202 		tcp->th_flags = TH_SYN;
1203 		tcp->th_sum = 0;
1204 		tcp->th_sum = tcp_chksum(&Src, &Dst, outpacket, datalen);
1205 		break;
1206 	default:
1207 		fprintf(stderr, "Unknown probe protocol %d.\n", useproto);
1208 		exit(1);
1209 	}
1210 
1211 	i = send(sndsock, (char *)outpacket, datalen, 0);
1212 	if (i < 0 || (u_long)i != datalen)  {
1213 		if (i < 0)
1214 			perror("send");
1215 		printf("traceroute6: wrote %s %lu chars, ret=%d\n",
1216 		    hostname, datalen, i);
1217 		(void) fflush(stdout);
1218 	}
1219 }
1220 
1221 int
1222 get_hoplim(struct msghdr *mhdr)
1223 {
1224 	struct cmsghdr *cm;
1225 
1226 	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(mhdr); cm;
1227 	    cm = (struct cmsghdr *)CMSG_NXTHDR(mhdr, cm)) {
1228 		if (cm->cmsg_level == IPPROTO_IPV6 &&
1229 		    cm->cmsg_type == IPV6_HOPLIMIT &&
1230 		    cm->cmsg_len == CMSG_LEN(sizeof(int)))
1231 			return (*(int *)CMSG_DATA(cm));
1232 	}
1233 
1234 	return (-1);
1235 }
1236 
1237 double
1238 deltaT(struct timeval *t1p, struct timeval *t2p)
1239 {
1240 	double dt;
1241 
1242 	dt = (double)(t2p->tv_sec - t1p->tv_sec) * 1000.0 +
1243 	    (double)(t2p->tv_usec - t1p->tv_usec) / 1000.0;
1244 	return (dt);
1245 }
1246 
1247 /*
1248  * Convert an ICMP "type" field to a printable string.
1249  */
1250 const char *
1251 pr_type(int t0)
1252 {
1253 	u_char t = t0 & 0xff;
1254 	const char *cp;
1255 
1256 	switch (t) {
1257 	case ICMP6_DST_UNREACH:
1258 		cp = "Destination Unreachable";
1259 		break;
1260 	case ICMP6_PACKET_TOO_BIG:
1261 		cp = "Packet Too Big";
1262 		break;
1263 	case ICMP6_TIME_EXCEEDED:
1264 		cp = "Time Exceeded";
1265 		break;
1266 	case ICMP6_PARAM_PROB:
1267 		cp = "Parameter Problem";
1268 		break;
1269 	case ICMP6_ECHO_REQUEST:
1270 		cp = "Echo Request";
1271 		break;
1272 	case ICMP6_ECHO_REPLY:
1273 		cp = "Echo Reply";
1274 		break;
1275 	case ICMP6_MEMBERSHIP_QUERY:
1276 		cp = "Group Membership Query";
1277 		break;
1278 	case ICMP6_MEMBERSHIP_REPORT:
1279 		cp = "Group Membership Report";
1280 		break;
1281 	case ICMP6_MEMBERSHIP_REDUCTION:
1282 		cp = "Group Membership Reduction";
1283 		break;
1284 	case ND_ROUTER_SOLICIT:
1285 		cp = "Router Solicitation";
1286 		break;
1287 	case ND_ROUTER_ADVERT:
1288 		cp = "Router Advertisement";
1289 		break;
1290 	case ND_NEIGHBOR_SOLICIT:
1291 		cp = "Neighbor Solicitation";
1292 		break;
1293 	case ND_NEIGHBOR_ADVERT:
1294 		cp = "Neighbor Advertisement";
1295 		break;
1296 	case ND_REDIRECT:
1297 		cp = "Redirect";
1298 		break;
1299 	default:
1300 		cp = "Unknown";
1301 		break;
1302 	}
1303 	return cp;
1304 }
1305 
1306 int
1307 packet_ok(struct msghdr *mhdr, int cc, int seq, u_char *type, u_char *code)
1308 {
1309 	struct icmp6_hdr *icp;
1310 	struct sockaddr_in6 *from = (struct sockaddr_in6 *)mhdr->msg_name;
1311 	char *buf = (char *)mhdr->msg_iov[0].iov_base;
1312 	struct cmsghdr *cm;
1313 	int *hlimp;
1314 	char hbuf[NI_MAXHOST];
1315 
1316 #ifdef OLDRAWSOCKET
1317 	int hlen;
1318 	struct ip6_hdr *ip;
1319 #endif
1320 
1321 #ifdef OLDRAWSOCKET
1322 	ip = (struct ip6_hdr *) buf;
1323 	hlen = sizeof(struct ip6_hdr);
1324 	if (cc < hlen + sizeof(struct icmp6_hdr)) {
1325 		if (verbose) {
1326 			if (cap_getnameinfo(capdns, (struct sockaddr *)from, from->sin6_len,
1327 			    hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0)
1328 				strlcpy(hbuf, "invalid", sizeof(hbuf));
1329 			printf("packet too short (%d bytes) from %s\n", cc,
1330 			    hbuf);
1331 		}
1332 		return (0);
1333 	}
1334 	cc -= hlen;
1335 	icp = (struct icmp6_hdr *)(buf + hlen);
1336 #else
1337 	if (cc < (int)sizeof(struct icmp6_hdr)) {
1338 		if (verbose) {
1339 			if (cap_getnameinfo(capdns, (struct sockaddr *)from, from->sin6_len,
1340 			    hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0)
1341 				strlcpy(hbuf, "invalid", sizeof(hbuf));
1342 			printf("data too short (%d bytes) from %s\n", cc, hbuf);
1343 		}
1344 		return (0);
1345 	}
1346 	icp = (struct icmp6_hdr *)buf;
1347 #endif
1348 	/* get optional information via advanced API */
1349 	rcvpktinfo = NULL;
1350 	hlimp = NULL;
1351 	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(mhdr); cm;
1352 	    cm = (struct cmsghdr *)CMSG_NXTHDR(mhdr, cm)) {
1353 		if (cm->cmsg_level == IPPROTO_IPV6 &&
1354 		    cm->cmsg_type == IPV6_PKTINFO &&
1355 		    cm->cmsg_len ==
1356 		    CMSG_LEN(sizeof(struct in6_pktinfo)))
1357 			rcvpktinfo = (struct in6_pktinfo *)(CMSG_DATA(cm));
1358 
1359 		if (cm->cmsg_level == IPPROTO_IPV6 &&
1360 		    cm->cmsg_type == IPV6_HOPLIMIT &&
1361 		    cm->cmsg_len == CMSG_LEN(sizeof(int)))
1362 			hlimp = (int *)CMSG_DATA(cm);
1363 	}
1364 	if (rcvpktinfo == NULL || hlimp == NULL) {
1365 		warnx("failed to get received hop limit or packet info");
1366 #if 0
1367 		return (0);
1368 #else
1369 		rcvhlim = 0;	/*XXX*/
1370 #endif
1371 	}
1372 	else
1373 		rcvhlim = *hlimp;
1374 
1375 	*type = icp->icmp6_type;
1376 	*code = icp->icmp6_code;
1377 	if ((*type == ICMP6_TIME_EXCEEDED &&
1378 	    *code == ICMP6_TIME_EXCEED_TRANSIT) ||
1379 	    (*type == ICMP6_DST_UNREACH) ||
1380 	    (*type == ICMP6_PARAM_PROB &&
1381 	    *code == ICMP6_PARAMPROB_NEXTHEADER)) {
1382 		struct ip6_hdr *hip;
1383 		struct icmp6_hdr *icmp;
1384 		struct sctp_init_chunk *init;
1385 		struct sctphdr *sctp;
1386 		struct tcphdr *tcp;
1387 		struct udphdr *udp;
1388 		void *up;
1389 
1390 		hip = (struct ip6_hdr *)(icp + 1);
1391 		if ((up = get_uphdr(hip, (u_char *)(buf + cc))) == NULL) {
1392 			if (verbose)
1393 				warnx("failed to get upper layer header");
1394 			return (0);
1395 		}
1396 		switch (useproto) {
1397 		case IPPROTO_ICMPV6:
1398 			icmp = (struct icmp6_hdr *)up;
1399 			if (icmp->icmp6_id == ident &&
1400 			    icmp->icmp6_seq == htons(seq))
1401 				return (1);
1402 			break;
1403 		case IPPROTO_UDP:
1404 			udp = (struct udphdr *)up;
1405 			if (udp->uh_sport == htons(ident) &&
1406 			    udp->uh_dport == htons(port + seq))
1407 				return (1);
1408 			break;
1409 		case IPPROTO_SCTP:
1410 			sctp = (struct sctphdr *)up;
1411 			if (sctp->src_port != htons(ident) ||
1412 			    sctp->dest_port != htons(port + seq)) {
1413 				break;
1414 			}
1415 			if (datalen >= (u_long)(sizeof(struct sctphdr) +
1416 			    sizeof(struct sctp_init_chunk))) {
1417 				if (sctp->v_tag != 0) {
1418 					break;
1419 				}
1420 				init = (struct sctp_init_chunk *)(sctp + 1);
1421 				/* Check the initiate tag, if available. */
1422 				if ((char *)&init->init.a_rwnd > buf + cc) {
1423 					return (1);
1424 				}
1425 				if (init->init.initiate_tag == (u_int32_t)
1426 				    ((sctp->src_port << 16) | sctp->dest_port)) {
1427 					return (1);
1428 				}
1429 			} else {
1430 				if (sctp->v_tag ==
1431 				    (u_int32_t)((sctp->src_port << 16) |
1432 				    sctp->dest_port)) {
1433 					return (1);
1434 				}
1435 			}
1436 			break;
1437 		case IPPROTO_TCP:
1438 			tcp = (struct tcphdr *)up;
1439 			if (tcp->th_sport == htons(ident) &&
1440 			    tcp->th_dport == htons(port + seq) &&
1441 			    tcp->th_seq ==
1442 			    (tcp_seq)((tcp->th_sport << 16) | tcp->th_dport))
1443 				return (1);
1444 			break;
1445 		case IPPROTO_NONE:
1446 			return (1);
1447 		default:
1448 			fprintf(stderr, "Unknown probe proto %d.\n", useproto);
1449 			break;
1450 		}
1451 	} else if (useproto == IPPROTO_ICMPV6 && *type == ICMP6_ECHO_REPLY) {
1452 		if (icp->icmp6_id == ident &&
1453 		    icp->icmp6_seq == htons(seq))
1454 			return (1);
1455 	}
1456 	if (verbose) {
1457 		char sbuf[NI_MAXHOST+1], dbuf[INET6_ADDRSTRLEN];
1458 		u_int8_t *p;
1459 		int i;
1460 
1461 		if (cap_getnameinfo(capdns, (struct sockaddr *)from, from->sin6_len,
1462 		    sbuf, sizeof(sbuf), NULL, 0, NI_NUMERICHOST) != 0)
1463 			strlcpy(sbuf, "invalid", sizeof(sbuf));
1464 		printf("\n%d bytes from %s to %s", cc, sbuf,
1465 		    rcvpktinfo ? inet_ntop(AF_INET6, &rcvpktinfo->ipi6_addr,
1466 		    dbuf, sizeof(dbuf)) : "?");
1467 		printf(": icmp type %d (%s) code %d\n", *type, pr_type(*type),
1468 		    *code);
1469 		p = (u_int8_t *)(icp + 1);
1470 #define WIDTH	16
1471 		for (i = 0; i < cc; i++) {
1472 			if (i % WIDTH == 0)
1473 				printf("%04x:", i);
1474 			if (i % 4 == 0)
1475 				printf(" ");
1476 			printf("%02x", p[i]);
1477 			if (i % WIDTH == WIDTH - 1)
1478 				printf("\n");
1479 		}
1480 		if (cc % WIDTH != 0)
1481 			printf("\n");
1482 	}
1483 	return (0);
1484 }
1485 
1486 /*
1487  * Increment pointer until find the UDP or ICMP header.
1488  */
1489 void *
1490 get_uphdr(struct ip6_hdr *ip6, u_char *lim)
1491 {
1492 	u_char *cp = (u_char *)ip6, nh;
1493 	int hlen;
1494 	static u_char none_hdr[1]; /* Fake pointer for IPPROTO_NONE. */
1495 
1496 	if (cp + sizeof(*ip6) > lim)
1497 		return (NULL);
1498 
1499 	nh = ip6->ip6_nxt;
1500 	cp += sizeof(struct ip6_hdr);
1501 
1502 	while (lim - cp >= (nh == IPPROTO_NONE ? 0 : 8)) {
1503 		switch (nh) {
1504 		case IPPROTO_ESP:
1505 			return (NULL);
1506 		case IPPROTO_ICMPV6:
1507 			return (useproto == nh ? cp : NULL);
1508 		case IPPROTO_SCTP:
1509 		case IPPROTO_TCP:
1510 		case IPPROTO_UDP:
1511 			return (useproto == nh ? cp : NULL);
1512 		case IPPROTO_NONE:
1513 			return (useproto == nh ? none_hdr : NULL);
1514 		case IPPROTO_FRAGMENT:
1515 			hlen = sizeof(struct ip6_frag);
1516 			nh = ((struct ip6_frag *)cp)->ip6f_nxt;
1517 			break;
1518 		case IPPROTO_AH:
1519 			hlen = (((struct ip6_ext *)cp)->ip6e_len + 2) << 2;
1520 			nh = ((struct ip6_ext *)cp)->ip6e_nxt;
1521 			break;
1522 		default:
1523 			hlen = (((struct ip6_ext *)cp)->ip6e_len + 1) << 3;
1524 			nh = ((struct ip6_ext *)cp)->ip6e_nxt;
1525 			break;
1526 		}
1527 
1528 		cp += hlen;
1529 	}
1530 
1531 	return (NULL);
1532 }
1533 
1534 void
1535 capdns_open(void)
1536 {
1537 #ifdef	WITH_CASPER
1538 	const char *types[] = { "NAME", "ADDR" };
1539 	int families[1];
1540 	cap_channel_t *casper;
1541 
1542 	casper = cap_init();
1543 	if (casper == NULL)
1544 		errx(1, "unable to create casper process");
1545 	capdns = cap_service_open(casper, "system.dns");
1546 	if (capdns == NULL)
1547 		errx(1, "unable to open system.dns service");
1548 	if (cap_dns_type_limit(capdns, types, nitems(types)) < 0)
1549 		errx(1, "unable to limit access to system.dns service");
1550 	families[0] = AF_INET6;
1551 	if (cap_dns_family_limit(capdns, families, nitems(families)) < 0)
1552 		errx(1, "unable to limit access to system.dns service");
1553 	cap_close(casper);
1554 #endif	/* WITH_CASPER */
1555 }
1556 
1557 void
1558 print(struct msghdr *mhdr, int cc)
1559 {
1560 	struct sockaddr_in6 *from = (struct sockaddr_in6 *)mhdr->msg_name;
1561 	char hbuf[NI_MAXHOST];
1562 
1563 	if (cap_getnameinfo(capdns, (struct sockaddr *)from, from->sin6_len,
1564 	    hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0)
1565 		strlcpy(hbuf, "invalid", sizeof(hbuf));
1566 	if (as_path)
1567 		printf(" [AS%u]", as_lookup(asn, hbuf, AF_INET6));
1568 	if (nflag)
1569 		printf(" %s", hbuf);
1570 	else if (lflag)
1571 		printf(" %s (%s)", inetname((struct sockaddr *)from), hbuf);
1572 	else
1573 		printf(" %s", inetname((struct sockaddr *)from));
1574 
1575 	if (verbose) {
1576 #ifdef OLDRAWSOCKET
1577 		printf(" %d bytes to %s", cc,
1578 		    rcvpktinfo ? inet_ntop(AF_INET6, &rcvpktinfo->ipi6_addr,
1579 		    hbuf, sizeof(hbuf)) : "?");
1580 #else
1581 		printf(" %d bytes of data to %s", cc,
1582 		    rcvpktinfo ?  inet_ntop(AF_INET6, &rcvpktinfo->ipi6_addr,
1583 		    hbuf, sizeof(hbuf)) : "?");
1584 #endif
1585 	}
1586 }
1587 
1588 /*
1589  * Construct an Internet address representation.
1590  * If the nflag has been supplied, give
1591  * numeric value, otherwise try for symbolic name.
1592  */
1593 const char *
1594 inetname(struct sockaddr *sa)
1595 {
1596 	static char line[NI_MAXHOST], domain[MAXHOSTNAMELEN + 1];
1597 	static int first = 1;
1598 	char *cp;
1599 
1600 	if (first && !nflag) {
1601 		first = 0;
1602 		if (gethostname(domain, sizeof(domain)) == 0 &&
1603 		    (cp = strchr(domain, '.')))
1604 			(void) strlcpy(domain, cp + 1, sizeof(domain));
1605 		else
1606 			domain[0] = 0;
1607 	}
1608 	cp = NULL;
1609 	if (!nflag) {
1610 		if (cap_getnameinfo(capdns, sa, sa->sa_len, line, sizeof(line), NULL, 0,
1611 		    NI_NAMEREQD) == 0) {
1612 			if ((cp = strchr(line, '.')) &&
1613 			    !strcmp(cp + 1, domain))
1614 				*cp = 0;
1615 			cp = line;
1616 		}
1617 	}
1618 	if (cp)
1619 		return cp;
1620 
1621 	if (cap_getnameinfo(capdns, sa, sa->sa_len, line, sizeof(line), NULL, 0,
1622 	    NI_NUMERICHOST) != 0)
1623 		strlcpy(line, "invalid", sizeof(line));
1624 	return line;
1625 }
1626 
1627 /*
1628  * CRC32C routine for the Stream Control Transmission Protocol
1629  */
1630 
1631 #define CRC32C(c, d) (c = (c>>8) ^ crc_c[(c^(d))&0xFF])
1632 
1633 static u_int32_t crc_c[256] = {
1634 	0x00000000, 0xF26B8303, 0xE13B70F7, 0x1350F3F4,
1635 	0xC79A971F, 0x35F1141C, 0x26A1E7E8, 0xD4CA64EB,
1636 	0x8AD958CF, 0x78B2DBCC, 0x6BE22838, 0x9989AB3B,
1637 	0x4D43CFD0, 0xBF284CD3, 0xAC78BF27, 0x5E133C24,
1638 	0x105EC76F, 0xE235446C, 0xF165B798, 0x030E349B,
1639 	0xD7C45070, 0x25AFD373, 0x36FF2087, 0xC494A384,
1640 	0x9A879FA0, 0x68EC1CA3, 0x7BBCEF57, 0x89D76C54,
1641 	0x5D1D08BF, 0xAF768BBC, 0xBC267848, 0x4E4DFB4B,
1642 	0x20BD8EDE, 0xD2D60DDD, 0xC186FE29, 0x33ED7D2A,
1643 	0xE72719C1, 0x154C9AC2, 0x061C6936, 0xF477EA35,
1644 	0xAA64D611, 0x580F5512, 0x4B5FA6E6, 0xB93425E5,
1645 	0x6DFE410E, 0x9F95C20D, 0x8CC531F9, 0x7EAEB2FA,
1646 	0x30E349B1, 0xC288CAB2, 0xD1D83946, 0x23B3BA45,
1647 	0xF779DEAE, 0x05125DAD, 0x1642AE59, 0xE4292D5A,
1648 	0xBA3A117E, 0x4851927D, 0x5B016189, 0xA96AE28A,
1649 	0x7DA08661, 0x8FCB0562, 0x9C9BF696, 0x6EF07595,
1650 	0x417B1DBC, 0xB3109EBF, 0xA0406D4B, 0x522BEE48,
1651 	0x86E18AA3, 0x748A09A0, 0x67DAFA54, 0x95B17957,
1652 	0xCBA24573, 0x39C9C670, 0x2A993584, 0xD8F2B687,
1653 	0x0C38D26C, 0xFE53516F, 0xED03A29B, 0x1F682198,
1654 	0x5125DAD3, 0xA34E59D0, 0xB01EAA24, 0x42752927,
1655 	0x96BF4DCC, 0x64D4CECF, 0x77843D3B, 0x85EFBE38,
1656 	0xDBFC821C, 0x2997011F, 0x3AC7F2EB, 0xC8AC71E8,
1657 	0x1C661503, 0xEE0D9600, 0xFD5D65F4, 0x0F36E6F7,
1658 	0x61C69362, 0x93AD1061, 0x80FDE395, 0x72966096,
1659 	0xA65C047D, 0x5437877E, 0x4767748A, 0xB50CF789,
1660 	0xEB1FCBAD, 0x197448AE, 0x0A24BB5A, 0xF84F3859,
1661 	0x2C855CB2, 0xDEEEDFB1, 0xCDBE2C45, 0x3FD5AF46,
1662 	0x7198540D, 0x83F3D70E, 0x90A324FA, 0x62C8A7F9,
1663 	0xB602C312, 0x44694011, 0x5739B3E5, 0xA55230E6,
1664 	0xFB410CC2, 0x092A8FC1, 0x1A7A7C35, 0xE811FF36,
1665 	0x3CDB9BDD, 0xCEB018DE, 0xDDE0EB2A, 0x2F8B6829,
1666 	0x82F63B78, 0x709DB87B, 0x63CD4B8F, 0x91A6C88C,
1667 	0x456CAC67, 0xB7072F64, 0xA457DC90, 0x563C5F93,
1668 	0x082F63B7, 0xFA44E0B4, 0xE9141340, 0x1B7F9043,
1669 	0xCFB5F4A8, 0x3DDE77AB, 0x2E8E845F, 0xDCE5075C,
1670 	0x92A8FC17, 0x60C37F14, 0x73938CE0, 0x81F80FE3,
1671 	0x55326B08, 0xA759E80B, 0xB4091BFF, 0x466298FC,
1672 	0x1871A4D8, 0xEA1A27DB, 0xF94AD42F, 0x0B21572C,
1673 	0xDFEB33C7, 0x2D80B0C4, 0x3ED04330, 0xCCBBC033,
1674 	0xA24BB5A6, 0x502036A5, 0x4370C551, 0xB11B4652,
1675 	0x65D122B9, 0x97BAA1BA, 0x84EA524E, 0x7681D14D,
1676 	0x2892ED69, 0xDAF96E6A, 0xC9A99D9E, 0x3BC21E9D,
1677 	0xEF087A76, 0x1D63F975, 0x0E330A81, 0xFC588982,
1678 	0xB21572C9, 0x407EF1CA, 0x532E023E, 0xA145813D,
1679 	0x758FE5D6, 0x87E466D5, 0x94B49521, 0x66DF1622,
1680 	0x38CC2A06, 0xCAA7A905, 0xD9F75AF1, 0x2B9CD9F2,
1681 	0xFF56BD19, 0x0D3D3E1A, 0x1E6DCDEE, 0xEC064EED,
1682 	0xC38D26C4, 0x31E6A5C7, 0x22B65633, 0xD0DDD530,
1683 	0x0417B1DB, 0xF67C32D8, 0xE52CC12C, 0x1747422F,
1684 	0x49547E0B, 0xBB3FFD08, 0xA86F0EFC, 0x5A048DFF,
1685 	0x8ECEE914, 0x7CA56A17, 0x6FF599E3, 0x9D9E1AE0,
1686 	0xD3D3E1AB, 0x21B862A8, 0x32E8915C, 0xC083125F,
1687 	0x144976B4, 0xE622F5B7, 0xF5720643, 0x07198540,
1688 	0x590AB964, 0xAB613A67, 0xB831C993, 0x4A5A4A90,
1689 	0x9E902E7B, 0x6CFBAD78, 0x7FAB5E8C, 0x8DC0DD8F,
1690 	0xE330A81A, 0x115B2B19, 0x020BD8ED, 0xF0605BEE,
1691 	0x24AA3F05, 0xD6C1BC06, 0xC5914FF2, 0x37FACCF1,
1692 	0x69E9F0D5, 0x9B8273D6, 0x88D28022, 0x7AB90321,
1693 	0xAE7367CA, 0x5C18E4C9, 0x4F48173D, 0xBD23943E,
1694 	0xF36E6F75, 0x0105EC76, 0x12551F82, 0xE03E9C81,
1695 	0x34F4F86A, 0xC69F7B69, 0xD5CF889D, 0x27A40B9E,
1696 	0x79B737BA, 0x8BDCB4B9, 0x988C474D, 0x6AE7C44E,
1697 	0xBE2DA0A5, 0x4C4623A6, 0x5F16D052, 0xAD7D5351
1698 };
1699 
1700 u_int32_t
1701 sctp_crc32c(void *pack, u_int32_t len)
1702 {
1703 	u_int32_t i, crc32c;
1704 	u_int8_t byte0, byte1, byte2, byte3;
1705 	u_int8_t *buf = (u_int8_t *)pack;
1706 
1707 	crc32c = ~0;
1708 	for (i = 0; i < len; i++)
1709 		CRC32C(crc32c, buf[i]);
1710 	crc32c = ~crc32c;
1711 	byte0  = crc32c & 0xff;
1712 	byte1  = (crc32c>>8) & 0xff;
1713 	byte2  = (crc32c>>16) & 0xff;
1714 	byte3  = (crc32c>>24) & 0xff;
1715 	crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
1716 	return htonl(crc32c);
1717 }
1718 
1719 u_int16_t
1720 in_cksum(u_int16_t *addr, int len)
1721 {
1722 	int nleft = len;
1723 	u_int16_t *w = addr;
1724 	u_int16_t answer;
1725 	int sum = 0;
1726 
1727 	/*
1728 	 *  Our algorithm is simple, using a 32 bit accumulator (sum),
1729 	 *  we add sequential 16 bit words to it, and at the end, fold
1730 	 *  back all the carry bits from the top 16 bits into the lower
1731 	 *  16 bits.
1732 	 */
1733 	while (nleft > 1)  {
1734 		sum += *w++;
1735 		nleft -= 2;
1736 	}
1737 
1738 	/* mop up an odd byte, if necessary */
1739 	if (nleft == 1)
1740 		sum += *(u_char *)w;
1741 
1742 	/*
1743 	 * add back carry outs from top 16 bits to low 16 bits
1744 	 */
1745 	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
1746 	sum += (sum >> 16);			/* add carry */
1747 	answer = ~sum;				/* truncate to 16 bits */
1748 	return (answer);
1749 }
1750 
1751 u_int16_t
1752 udp_cksum(struct sockaddr_in6 *src, struct sockaddr_in6 *dst,
1753     void *payload, u_int32_t len)
1754 {
1755 	struct {
1756 		struct in6_addr src;
1757 		struct in6_addr dst;
1758 		u_int32_t len;
1759 		u_int8_t zero[3];
1760 		u_int8_t next;
1761 	} pseudo_hdr;
1762 	u_int16_t sum[2];
1763 
1764 	pseudo_hdr.src = src->sin6_addr;
1765 	pseudo_hdr.dst = dst->sin6_addr;
1766 	pseudo_hdr.len = htonl(len);
1767 	pseudo_hdr.zero[0] = 0;
1768 	pseudo_hdr.zero[1] = 0;
1769 	pseudo_hdr.zero[2] = 0;
1770 	pseudo_hdr.next = IPPROTO_UDP;
1771 
1772 	sum[1] = in_cksum((u_int16_t *)&pseudo_hdr, sizeof(pseudo_hdr));
1773 	sum[0] = in_cksum(payload, len);
1774 
1775 	return (~in_cksum(sum, sizeof(sum)));
1776 }
1777 
1778 u_int16_t
1779 tcp_chksum(struct sockaddr_in6 *src, struct sockaddr_in6 *dst,
1780     void *payload, u_int32_t len)
1781 {
1782 	struct {
1783 		struct in6_addr src;
1784 		struct in6_addr dst;
1785 		u_int32_t len;
1786 		u_int8_t zero[3];
1787 		u_int8_t next;
1788 	} pseudo_hdr;
1789 	u_int16_t sum[2];
1790 
1791 	pseudo_hdr.src = src->sin6_addr;
1792 	pseudo_hdr.dst = dst->sin6_addr;
1793 	pseudo_hdr.len = htonl(len);
1794 	pseudo_hdr.zero[0] = 0;
1795 	pseudo_hdr.zero[1] = 0;
1796 	pseudo_hdr.zero[2] = 0;
1797 	pseudo_hdr.next = IPPROTO_TCP;
1798 
1799 	sum[1] = in_cksum((u_int16_t *)&pseudo_hdr, sizeof(pseudo_hdr));
1800 	sum[0] = in_cksum(payload, len);
1801 
1802 	return (~in_cksum(sum, sizeof(sum)));
1803 }
1804 
1805 void
1806 usage(void)
1807 {
1808 
1809 	fprintf(stderr,
1810 "usage: traceroute6 [-adIlnNrSTUv] [-A as_server] [-f firsthop] [-g gateway]\n"
1811 "       [-m hoplimit] [-p port] [-q probes] [-s src] [-w waittime] target\n"
1812 "       [datalen]\n");
1813 	exit(1);
1814 }
1815