xref: /titanic_44/usr/src/cmd/cmd-inet/usr.sbin/traceroute/traceroute.c (revision 8eea8e29cc4374d1ee24c25a07f45af132db3499)
1 /*
2  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 /*
7  * Copyright (c) 1988, 1989, 1991, 1994, 1995, 1996, 1997
8  *	The Regents of the University of California.  All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that: (1) source code distributions
12  * retain the above copyright notice and this paragraph in its entirety, (2)
13  * distributions including binary code include the above copyright notice and
14  * this paragraph in its entirety in the documentation or other materials
15  * provided with the distribution, and (3) all advertising materials mentioning
16  * features or use of this software display the following acknowledgement:
17  * ``This product includes software developed by the University of California,
18  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
19  * the University nor the names of its contributors may be used to endorse
20  * or promote products derived from this software without specific prior
21  * written permission.
22  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
23  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
25  *
26  *
27  * @(#)$Header: traceroute.c,v 1.49 97/06/13 02:30:23 leres Exp $ (LBL)
28  */
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include <sys/param.h>
33 #include <sys/file.h>
34 #include <sys/ioctl.h>
35 #include <sys/socket.h>
36 #include <sys/time.h>
37 #include <sys/sysmacros.h>
38 
39 #include <netinet/in_systm.h>
40 #include <netinet/in.h>
41 #include <netinet/ip.h>
42 #include <netinet/ip_var.h>
43 #include <netinet/ip_icmp.h>
44 #include <netinet/udp.h>
45 #include <netinet/udp_var.h>
46 #include <netinet/ip6.h>
47 #include <netinet/icmp6.h>
48 
49 #include <arpa/inet.h>
50 
51 #include <ctype.h>
52 #include <errno.h>
53 #include <malloc.h>
54 #include <memory.h>
55 #include <netdb.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <strings.h>
59 #include <unistd.h>
60 #include <libintl.h>
61 #include <locale.h>
62 #include <signal.h>
63 #include <setjmp.h>
64 #include <limits.h>
65 #include <zone.h>
66 
67 #include <priv_utils.h>
68 
69 
70 #include <ifaddrlist.h>
71 #include "traceroute.h"
72 
73 #define	MAX_SEQ			65535	/* max sequence value for ICMP */
74 #define	MAX_TRAFFIC_CLASS	255	/* max traffic class for IPv6 */
75 #define	MAX_FLOW_LABEL		0xFFFFF	/* max flow label for IPv6 */
76 #define	MAX_TOS			255	/* max type-of-service for IPv4 */
77 #define	STR_LEN			30
78 
79 /* store the information about a host */
80 struct hostinfo {
81 	char *name;		/* hostname */
82 	int family;		/* address family of the IP addresses */
83 	int num_addr;			/* number of IP addresses */
84 	union any_in_addr *addrs;	/* list of IP addresses */
85 };
86 
87 /* used to store a bunch of protocol specific values */
88 struct pr_set {
89 	int family;		/* AF_INET or AF_INET6 */
90 	char name[STR_LEN];	/* "IPv4" or "IPv6" */
91 	char icmp[STR_LEN];	/* "icmp" or "ipv6-icmp" */
92 	int icmp_minlen;
93 	int addr_len;
94 	int ip_hdr_len;
95 	int packlen;
96 	int sock_size;		/* size of sockaddr_in or sockaddr_in6 */
97 	struct sockaddr *to;
98 	struct sockaddr *from;
99 	void *from_sin_addr;
100 	union any_in_addr *gwIPlist;
101 	/* pointers to v4/v6 functions */
102 	struct ip *(*set_buffers_fn) (int);
103 	int (*check_reply_fn)(struct msghdr *, int, int, uchar_t *, uchar_t *);
104 	boolean_t (*print_icmp_other_fn)(uchar_t, uchar_t);
105 	void (*print_addr_fn)(uchar_t *, int, struct sockaddr *);
106 
107 };
108 
109 /*
110  * LBNL bug fixed: in LBNL traceroute 'uchar_t packet[512];'
111  * Not sufficient to hold the complete packet for ECHO REPLY of a big probe.
112  * Packet size is reported incorrectly in such a case.
113  * Also this buffer needs to be 32 bit aligned. In the future the alignment
114  * requirement will be increased to 64 bit. So, let's use 64 bit alignment now.
115  */
116 static uint64_t packet[(IP_MAXPACKET + 1)/8];	/* received packet */
117 
118 static struct ip *outip4;	/* output buffer to send as an IPv4 datagram */
119 static struct ip *outip6;	/* output buffer to send as an IPv6 datagram */
120 
121 /* Used to store the ancillary data that comes with the received packets */
122 static uint64_t ancillary_data[(IP_MAXPACKET + 1)/8];
123 
124 /* first get the gw names, later you'll resolve them based on the family */
125 static char *gwlist[MAXMAX_GWS];		/* gateway names list */
126 static union any_in_addr gwIPlist[MAX_GWS];	/* gateway IPv4 address list */
127 static union any_in_addr gwIP6list[MAX_GWS6];	/* gateway IPv6 address list */
128 
129 static int family_input = AF_UNSPEC;	/* User supplied protocol family */
130 static int rcvsock4;		/* receive (icmp) socket file descriptor */
131 static int sndsock4;		/* send (udp/icmp) socket file descriptor */
132 static int rcvsock6;		/* receive (icmp6) socket file descriptor */
133 static int sndsock6;		/* send (udp6/icmp6) socket file descriptor */
134 int gw_count = 0;		/* number of gateways */
135 static struct sockaddr_in whereto;	/* Who to try to reach */
136 static struct sockaddr_in6 whereto6;
137 static struct sockaddr_in wherefrom;	/* Who we are */
138 static struct sockaddr_in6 wherefrom6;
139 static int packlen_input = 0;		/* user input for packlen */
140 
141 char *prog;
142 static char *source_input = NULL; /* this is user arg. source, doesn't change */
143 static char *source = NULL;	/* this gets modified after name lookup */
144 char *hostname;
145 static char *device = NULL;   	/* interface name */
146 static struct pr_set *pr4;	/* protocol info for IPv4 */
147 static struct pr_set *pr6;	/* protocol info for IPv6 */
148 static struct ifaddrlist *al4;	/* list of interfaces */
149 static struct ifaddrlist *al6;	/* list of interfaces */
150 static uint_t if_index = 0;	/* interface index */
151 static int num_v4 = 0;		/* count of IPv4 addresses */
152 static int num_v6 = 0;		/* count of IPv6 addresses */
153 static int num_ifs4 = 0;	/* count of local IPv4 interfaces */
154 static int num_ifs6 = 0;	/* count of local IPv6 interfaces */
155 
156 static int nprobes = 3;		/* number of probes */
157 static int max_ttl = 30;	/* max number of hops */
158 static int first_ttl = 1;	/* initial number of hops */
159 ushort_t ident;			/* used to authenticate replies */
160 ushort_t port = 32768 + 666;	/* start udp dest port # for probe packets */
161 
162 static int options = 0;		/* socket options */
163 boolean_t verbose = _B_FALSE;	/* verbose output */
164 static int waittime = 5;	/* time to wait for response (in seconds) */
165 static struct timeval delay = {0, 0}; /* delay between consecutive probe */
166 boolean_t nflag = _B_FALSE;	/* print addresses numerically */
167 static boolean_t showttl = _B_FALSE; /* print the ttl(hop limit) of recvd pkt */
168 boolean_t useicmp = _B_FALSE;  	/* use icmp echo instead of udp packets */
169 boolean_t docksum = _B_TRUE;	/* calculate checksums */
170 static boolean_t collect_stat = _B_FALSE;	/* print statistics */
171 boolean_t settos = _B_FALSE;   	/* set type-of-service field */
172 static int max_timeout = 5;	/* quit after this consecutive timeouts */
173 static boolean_t probe_all = _B_FALSE;	/* probe all the IFs of the target */
174 static boolean_t pick_src = _B_FALSE;	/* traceroute picks the src address */
175 
176 /*
177  * flow and class are specific to IPv6, tos and off are specific to IPv4.
178  * Each protocol uses the ones that are specific to itself, and ignores
179  * others.
180  */
181 static uint_t flow = 0;		/* IPv6 flow info */
182 static uint_t class = 0;	/* IPv6 class */
183 uchar_t tos = 0;		/* IPv4 type-of-service */
184 ushort_t off = 0;		/* set DF bit */
185 
186 static jmp_buf env;		/* stack environment for longjmp() */
187 boolean_t raw_req;		/* if sndsock for IPv4 must be raw */
188 
189 /* Forwards */
190 static uint_t calc_packetlen(int, struct pr_set *);
191 extern int check_reply(struct msghdr *, int, int, uchar_t *, uchar_t *);
192 extern int check_reply6(struct msghdr *, int, int, uchar_t *, uchar_t *);
193 static double deltaT(struct timeval *, struct timeval *);
194 static char *device_name(struct ifaddrlist *, int, union any_in_addr *,
195     struct pr_set *);
196 extern void *find_ancillary_data(struct msghdr *, int, int);
197 static boolean_t has_addr(struct addrinfo *, union any_in_addr *);
198 static struct ifaddrlist *find_device(struct ifaddrlist *, int, char *);
199 static struct ifaddrlist *find_ifaddr(struct ifaddrlist *, int,
200     union any_in_addr *, int);
201 static void get_gwaddrs(char **, int, union any_in_addr *,
202     union any_in_addr *, int *, int *);
203 static void get_hostinfo(char *, int, struct addrinfo **);
204 char *inet_name(union any_in_addr *, int);
205 ushort_t in_cksum(ushort_t *, int);
206 extern int ip_hdr_length_v6(ip6_t *, int, uint8_t *);
207 void main(int, char **);
208 extern char *pr_type(uchar_t);
209 extern char *pr_type6(uchar_t);
210 extern void print_addr(uchar_t *, int, struct sockaddr *);
211 extern void print_addr6(uchar_t *, int, struct sockaddr *);
212 extern boolean_t print_icmp_other(uchar_t, uchar_t);
213 extern boolean_t print_icmp_other6(uchar_t, uchar_t);
214 static void print_stats(int, int, double, double, double, double);
215 static void print_unknown_host_msg(const char *, const char *);
216 static void record_stats(double, int *, double *, double *, double *, double *);
217 static void resolve_nodes(int *, struct addrinfo **);
218 static void select_src_addr(union any_in_addr *, union any_in_addr *, int);
219 extern void send_probe(int, struct sockaddr *, struct ip *, int, int,
220     struct timeval *, int);
221 extern void send_probe6(int, struct msghdr *, struct ip *, int, int,
222     struct timeval *, int);
223 extern void set_ancillary_data(struct msghdr *, int, union any_in_addr *, int,
224     uint_t);
225 extern struct ip *set_buffers(int);
226 extern struct ip *set_buffers6(int);
227 extern void set_IPv4opt_sourcerouting(int, union any_in_addr *,
228     union any_in_addr *);
229 static void set_sin(struct sockaddr *, union any_in_addr *, int);
230 static int set_src_addr(struct pr_set *, struct ifaddrlist **);
231 static void setup_protocol(struct pr_set *, int);
232 static void setup_socket(struct pr_set *, int);
233 static void sig_handler(int);
234 static int str2int(const char *, const char *, int, int);
235 static double str2dbl(const char *, const char *, double, double);
236 static void trace_it(struct addrinfo *);
237 static void traceroute(union any_in_addr *, struct msghdr *, struct pr_set *,
238     int, struct ifaddrlist *);
239 static void tv_sub(struct timeval *, struct timeval *);
240 static void usage(void);
241 static int wait_for_reply(int, struct msghdr *, struct timeval *);
242 static double xsqrt(double);
243 
244 /*
245  * main
246  */
247 void
248 main(int argc, char **argv)
249 {
250 	struct addrinfo *ai_dst = NULL;		/* destination host */
251 	/*
252 	 * "probing_successful" indicates if we could successfully send probes,
253 	 * not necessarily received reply from the target (this behavior is from
254 	 * the original traceroute). It's _B_FALSE if packlen is invalid, or no
255 	 * interfaces found.
256 	 */
257 	boolean_t probing_successful = _B_FALSE;
258 	int longjmp_return;			/* return value from longjump */
259 	int i = 0;
260 	char *cp;
261 	int op;
262 	char *ep;
263 	char temp_buf[INET6_ADDRSTRLEN];	/* use for inet_ntop() */
264 	double pause;
265 
266 	/*
267 	 * A raw socket will be used for IPv4 if there is sufficient
268 	 * privilege.
269 	 */
270 	raw_req = priv_ineffect(PRIV_NET_RAWACCESS);
271 
272 	/*
273 	 * We'll need the privilege only when we open the sockets; that's
274 	 * when we'll fail if the program has insufficient privileges.
275 	 */
276 	(void) __init_suid_priv(PU_CLEARLIMITSET, PRIV_NET_ICMPACCESS,
277 	    raw_req ? PRIV_NET_RAWACCESS : NULL, NULL);
278 
279 	(void) setlinebuf(stdout);
280 
281 	if ((cp = strrchr(argv[0], '/')) != NULL)
282 		prog = cp + 1;
283 	else
284 		prog = argv[0];
285 
286 	opterr = 0;
287 	while ((op = getopt(argc, argv, "adFIlnrSvxA:c:f:g:i:L:m:P:p:Q:q:s:"
288 	    "t:w:")) != EOF) {
289 		switch (op) {
290 		case 'A':
291 			if (strcmp(optarg, "inet") == 0) {
292 				family_input = AF_INET;
293 			} else if (strcmp(optarg, "inet6") == 0) {
294 				family_input = AF_INET6;
295 			} else {
296 				Fprintf(stderr,
297 				    "%s: unknown address family %s\n",
298 				    prog, optarg);
299 				exit(EXIT_FAILURE);
300 			}
301 			break;
302 
303 		case 'a':
304 			probe_all = _B_TRUE;
305 			break;
306 
307 		case 'c':
308 			class = str2int(optarg, "traffic class", 0,
309 			    MAX_TRAFFIC_CLASS);
310 			break;
311 
312 		case 'd':
313 			options |= SO_DEBUG;
314 			break;
315 
316 		case 'f':
317 			first_ttl = str2int(optarg, "first ttl", 1, MAXTTL);
318 			break;
319 
320 		case 'F':
321 			off = IP_DF;
322 			break;
323 
324 		case 'g':
325 			if (!raw_req) {
326 				Fprintf(stderr,
327 				    "%s: privilege to specify a loose source "
328 				    "route gateway is unavailable\n",
329 				    prog);
330 				exit(EXIT_FAILURE);
331 			}
332 			if (gw_count > MAXMAX_GWS) {
333 				Fprintf(stderr,
334 				    "%s: Too many gateways\n", prog);
335 				exit(EXIT_FAILURE);
336 			}
337 			gwlist[gw_count] = strdup(optarg);
338 			if (gwlist[gw_count] == NULL) {
339 				Fprintf(stderr, "%s: strdup %s\n", prog,
340 				    strerror(errno));
341 				exit(EXIT_FAILURE);
342 			}
343 
344 			++gw_count;
345 			break;
346 
347 		case 'l':
348 			showttl = _B_TRUE;
349 			break;
350 
351 		case 'i':
352 			/* this can be IF name or IF index */
353 			if_index = (uint_t)strtol(optarg, &ep, 10);
354 
355 			/* convert IF index <-->  IF name */
356 			if (errno != 0 || *ep != '\0') {
357 				device = optarg;
358 				if_index = if_nametoindex((const char *)device);
359 
360 				/*
361 				 * In case it fails, check to see if the problem
362 				 * is other than "IF not found".
363 				 */
364 				if (if_index == 0 && errno != ENXIO) {
365 					Fprintf(stderr, "%s: if_nametoindex:"
366 					    "%s\n", prog, strerror(errno));
367 					exit(EXIT_FAILURE);
368 				}
369 			} else {
370 				device = (char *)malloc(LIFNAMSIZ + 1);
371 				if (device == NULL) {
372 					Fprintf(stderr, "%s: malloc: %s\n",
373 					    prog, strerror(errno));
374 					exit(EXIT_FAILURE);
375 				}
376 
377 				device = if_indextoname(if_index, device);
378 				if (device != NULL) {
379 					device[LIFNAMSIZ] = '\0';
380 				} else if (errno != ENXIO) {
381 					/*
382 					 * The problem was other than "index
383 					 * not found".
384 					 */
385 					Fprintf(stderr, "%s: if_indextoname:"
386 					    "%s\n", prog, strerror(errno));
387 					exit(EXIT_FAILURE);
388 				}
389 			}
390 
391 			if (device == NULL || if_index == 0) {
392 				Fprintf(stderr, "%s: interface %s "
393 				    "doesn't match any actual interfaces\n",
394 				    prog, optarg);
395 				exit(EXIT_FAILURE);
396 			}
397 			break;
398 
399 		case 'I':
400 			useicmp = _B_TRUE;
401 			break;
402 
403 		case 'L':
404 			flow = str2int(optarg, "flow label", 0, MAX_FLOW_LABEL);
405 			break;
406 
407 		case 'm':
408 			max_ttl = str2int(optarg, "max ttl(hop limit)", 1,
409 			    MAXTTL);
410 			break;
411 
412 		case 'n':
413 			nflag = _B_TRUE;
414 			break;
415 
416 		case 'P':
417 			pause = str2dbl(optarg, "pause", 0, INT_MAX);
418 			delay.tv_sec = (time_t)pause;
419 			delay.tv_usec = (suseconds_t)((pause - delay.tv_sec) *
420 			    1000000);
421 			break;
422 
423 		case 'p':
424 			port = str2int(optarg, "port", 1, MAX_PORT);
425 			break;
426 
427 		case 'Q':
428 			max_timeout = str2int(optarg, "max timeout", 1, -1);
429 			break;
430 
431 		case 'q':
432 			nprobes = str2int(optarg, "nprobes", 1, -1);
433 			break;
434 
435 		case 'r':
436 			options |= SO_DONTROUTE;
437 			break;
438 
439 		case 'S':
440 			collect_stat = _B_TRUE;
441 			break;
442 
443 		case 's':
444 			/*
445 			 * set the ip source address of the outbound
446 			 * probe (e.g., on a multi-homed host).
447 			 */
448 			source_input = optarg;
449 			break;
450 
451 		case 't':
452 			tos = (uchar_t)str2int(optarg, "tos", 0, MAX_TOS);
453 			settos = _B_TRUE;
454 			break;
455 
456 		case 'v':
457 			verbose = _B_TRUE;
458 			break;
459 
460 		case 'x':
461 			docksum = _B_FALSE;
462 			break;
463 
464 		case 'w':
465 			waittime = str2int(optarg, "wait time", 2, -1);
466 			break;
467 
468 		default:
469 			usage();
470 			break;
471 		}
472 	}
473 
474 	/*
475 	 * If it's probe_all, SIGQUIT makes traceroute exit(). But we set the
476 	 * address to jump back to in traceroute(). Until then, we'll need to
477 	 * temporarily specify one.
478 	 */
479 	if (probe_all) {
480 		if ((longjmp_return = setjmp(env)) != 0) {
481 			if (longjmp_return == SIGQUIT) {
482 				Printf("(exiting)\n");
483 				exit(EXIT_SUCCESS);
484 			} else {		/* should never happen */
485 				exit(EXIT_FAILURE);
486 			}
487 		}
488 		(void) signal(SIGQUIT, sig_handler);
489 	}
490 
491 	if ((gw_count > 0) && (options & SO_DONTROUTE)) {
492 		Fprintf(stderr, "%s: loose source route gateways (-g)"
493 		    " cannot be specified when probe packets are sent"
494 		    " directly to a host on an attached network (-r)\n",
495 		    prog);
496 		exit(EXIT_FAILURE);
497 	}
498 
499 	i = argc - optind;
500 	if (i == 1 || i == 2) {
501 		hostname = argv[optind];
502 
503 		if (i == 2) {
504 			/* accept any length now, we'll check it later */
505 			packlen_input = str2int(argv[optind + 1],
506 			    "packet length", 0, -1);
507 		}
508 	} else {
509 		usage();
510 	}
511 
512 	if (first_ttl > max_ttl) {
513 		Fprintf(stderr,
514 		    "%s: first ttl(hop limit) (%d) may not be greater"
515 		    " than max ttl(hop limit) (%d)\n",
516 		    prog, first_ttl, max_ttl);
517 		exit(EXIT_FAILURE);
518 	}
519 
520 	/* resolve hostnames */
521 	resolve_nodes(&family_input, &ai_dst);
522 	if (ai_dst == NULL) {
523 		exit(EXIT_FAILURE);
524 	}
525 
526 	/*
527 	 * If it's probe_all, SIGINT makes traceroute skip to probing next IP
528 	 * address of the target. The new interrupt handler is assigned in
529 	 * traceroute() function. Until then let's ignore the signal.
530 	 */
531 	if (probe_all)
532 		(void) signal(SIGINT, SIG_IGN);
533 
534 	ident = (getpid() & 0xffff) | 0x8000;
535 
536 	/*
537 	 * We KNOW that probe_all == TRUE if family is AF_UNSPEC,
538 	 * since family is set to the specific AF found unless it's
539 	 * probe_all. So if family == AF_UNSPEC, we need to init pr4 and pr6.
540 	 */
541 	switch (family_input) {
542 	case AF_UNSPEC:
543 		pr4 = (struct pr_set *)malloc(sizeof (struct pr_set));
544 		if (pr4 == NULL) {
545 			Fprintf(stderr,
546 			    "%s: malloc %s\n", prog, strerror(errno));
547 			exit(EXIT_FAILURE);
548 		}
549 		pr6 = (struct pr_set *)malloc(sizeof (struct pr_set));
550 		if (pr6 == NULL) {
551 			Fprintf(stderr,
552 			    "%s: malloc %s\n", prog, strerror(errno));
553 			exit(EXIT_FAILURE);
554 		}
555 		setup_protocol(pr6, AF_INET6);
556 		setup_protocol(pr4, AF_INET);
557 		outip6 = (*pr6->set_buffers_fn)(pr6->packlen);
558 		setup_socket(pr6, pr6->packlen);
559 
560 		outip4 = (*pr4->set_buffers_fn)(pr4->packlen);
561 		setup_socket(pr4, pr4->packlen);
562 		num_ifs6 = set_src_addr(pr6, &al6);
563 		num_ifs4 = set_src_addr(pr4, &al4);
564 		break;
565 	case AF_INET6:
566 		pr6 = (struct pr_set *)malloc(sizeof (struct pr_set));
567 		if (pr6 == NULL) {
568 			Fprintf(stderr,
569 			    "%s: malloc %s\n", prog, strerror(errno));
570 			exit(EXIT_FAILURE);
571 		}
572 		setup_protocol(pr6, AF_INET6);
573 		outip6 = (*pr6->set_buffers_fn)(pr6->packlen);
574 		setup_socket(pr6, pr6->packlen);
575 		num_ifs6 = set_src_addr(pr6, &al6);
576 		break;
577 	case AF_INET:
578 		pr4 = (struct pr_set *)malloc(sizeof (struct pr_set));
579 		if (pr4 == NULL) {
580 			Fprintf(stderr,
581 			    "%s: malloc %s\n", prog, strerror(errno));
582 			exit(EXIT_FAILURE);
583 		}
584 		setup_protocol(pr4, AF_INET);
585 		outip4 = (*pr4->set_buffers_fn)(pr4->packlen);
586 		setup_socket(pr4, pr4->packlen);
587 		num_ifs4 = set_src_addr(pr4, &al4);
588 		break;
589 	default:
590 		Fprintf(stderr, "%s: unknow address family.\n", prog);
591 		exit(EXIT_FAILURE);
592 	}
593 
594 	if (num_v4 + num_v6 > 1 && !probe_all) {
595 		if (ai_dst->ai_family == AF_INET) {
596 			Fprintf(stderr,
597 			    "%s: Warning: %s has multiple addresses;"
598 			    " using %s\n", prog, hostname,
599 			    inet_ntop(AF_INET,
600 			    /* LINTED E_BAD_PTR_CAST_ALIGN */
601 			    (void *)&((struct sockaddr_in *)
602 			    ai_dst->ai_addr)->sin_addr,
603 			    temp_buf, sizeof (temp_buf)));
604 		} else {
605 			Fprintf(stderr,
606 			    "%s: Warning: %s has multiple addresses;"
607 			    " using %s\n", prog, hostname,
608 			    inet_ntop(AF_INET6,
609 			    /* LINTED E_BAD_PTR_CAST_ALIGN */
610 			    (void *)&((struct sockaddr_in6 *)
611 			    ai_dst->ai_addr)->sin6_addr,
612 			    temp_buf, sizeof (temp_buf)));
613 		}
614 	}
615 
616 	if (num_ifs4 + num_ifs6 > 0) {
617 		trace_it(ai_dst);
618 		probing_successful = _B_TRUE;
619 	}
620 
621 	(void) close(rcvsock4);
622 	(void) close(sndsock4);
623 	(void) close(rcvsock6);
624 	(void) close(sndsock6);
625 
626 	/*
627 	 * if we could probe any of the IP addresses of the target, that means
628 	 * this was a successful operation
629 	 */
630 	if (probing_successful)
631 		exit(EXIT_SUCCESS);
632 	else
633 		exit(EXIT_FAILURE);
634 }
635 
636 /*
637  * print "unknown host" message
638  */
639 static void
640 print_unknown_host_msg(const char *protocol, const char *host)
641 {
642 	Fprintf(stderr, "%s: unknown%s host %s\n", prog, protocol, host);
643 }
644 
645 /*
646  * resolve destination host and gateways
647  */
648 static void
649 resolve_nodes(int *family, struct addrinfo **ai_dstp)
650 {
651 	struct addrinfo *ai_dst = NULL;
652 	struct addrinfo *aip = NULL;
653 	int num_resolved_gw = 0;
654 	int num_resolved_gw6 = 0;
655 
656 	get_hostinfo(hostname, *family, &ai_dst);
657 	if (ai_dst == NULL) {
658 		print_unknown_host_msg("", hostname);
659 		exit(EXIT_FAILURE);
660 	}
661 	/* Get a count of the v4 & v6 addresses */
662 	for (aip = ai_dst; aip != NULL; aip = aip->ai_next) {
663 		switch (aip->ai_family) {
664 		case AF_INET:
665 			num_v4++;
666 			break;
667 		case AF_INET6:
668 			num_v6++;
669 			break;
670 		}
671 	}
672 
673 	if (*family == AF_UNSPEC && !probe_all) {
674 		*family = ai_dst->ai_family;
675 	}
676 
677 	/* resolve gateways */
678 	if (gw_count > 0) {
679 		get_gwaddrs(gwlist, *family, gwIPlist, gwIP6list,
680 		    &num_resolved_gw, &num_resolved_gw6);
681 
682 		/* we couldn't resolve a gateway as an IPv6 host */
683 		if (num_resolved_gw6 != gw_count && num_v6 != 0) {
684 			if (*family == AF_INET6 || *family == AF_UNSPEC)
685 				print_unknown_host_msg(" IPv6",
686 				    gwlist[num_resolved_gw6]);
687 			num_v6 = 0;
688 		}
689 
690 		/* we couldn't resolve a gateway as an IPv4 host */
691 		if (num_resolved_gw != gw_count && num_v4 != 0) {
692 			if (*family == AF_INET || *family == AF_UNSPEC)
693 				print_unknown_host_msg(" IPv4",
694 				    gwlist[num_resolved_gw]);
695 			num_v4 = 0;
696 		}
697 	}
698 
699 	*ai_dstp = ai_dst;
700 }
701 
702 /*
703  * Given IP address or hostname, return v4 and v6 hostinfo lists.
704  * Assumes that hostinfo ** ptrs are non-null.
705  */
706 static void
707 get_hostinfo(char *host, int family, struct addrinfo **aipp)
708 {
709 	struct addrinfo hints, *ai;
710 	struct in6_addr addr6;
711 	struct in_addr addr;
712 	char temp_buf[INET6_ADDRSTRLEN];	/* use for inet_ntop() */
713 	int rc;
714 
715 	/*
716 	 * Take care of v4-mapped addresses. It should run same as v4, after
717 	 * chopping off the prefix, leaving the IPv4 address
718 	 */
719 	if ((inet_pton(AF_INET6, host, &addr6) > 0) &&
720 	    IN6_IS_ADDR_V4MAPPED(&addr6)) {
721 		/* peel off the "mapping" stuff, leaving 32 bit IPv4 address */
722 		IN6_V4MAPPED_TO_INADDR(&addr6, &addr);
723 
724 		/* convert it back to a string */
725 		(void) inet_ntop(AF_INET, (void *)&addr, temp_buf,
726 		    sizeof (temp_buf));
727 
728 		/* now the host is an IPv4 address */
729 		(void) strcpy(host, temp_buf);
730 
731 		/*
732 		 * If it's a mapped address, we convert it into IPv4
733 		 * address because traceroute will send and receive IPv4
734 		 * packets for that address. Therefore, it's a failure case to
735 		 * ask get_hostinfo() to treat a mapped address as an IPv6
736 		 * address.
737 		 */
738 		if (family == AF_INET6) {
739 			return;
740 		}
741 	}
742 
743 	(void) memset(&hints, 0, sizeof (hints));
744 	hints.ai_family = family;
745 	hints.ai_flags = AI_ADDRCONFIG;
746 	rc = getaddrinfo(host, NULL, &hints, &ai);
747 	if (rc != 0) {
748 		if (rc != EAI_NONAME)
749 			Fprintf(stderr, "%s: getaddrinfo: %s\n", prog,
750 			    gai_strerror(rc));
751 		return;
752 	}
753 	*aipp = ai;
754 }
755 
756 /*
757  * Calculate the packet length to be used, and check against the valid range.
758  * Returns -1 if range check fails.
759  */
760 static uint_t
761 calc_packetlen(int plen_input, struct pr_set *pr)
762 {
763 	int minpacket;			/* min ip packet size */
764 	int optlen;			/* length of ip options */
765 	int plen;
766 
767 	/*
768 	 * LBNL bug fixed: miscalculation of optlen
769 	 */
770 	if (gw_count > 0) {
771 		/*
772 		 * IPv4:
773 		 * ----
774 		 * 5 (NO OPs) + 3 (code, len, ptr) + gateways
775 		 * IP options field can hold up to 9 gateways. But the API
776 		 * allows you to specify only 8, because the last one is the
777 		 * destination host. When this packet is sent, on the wire
778 		 * you see one gateway replaced by 4 NO OPs. The other 1 NO
779 		 * OP is for alignment
780 		 *
781 		 * IPv6:
782 		 * ----
783 		 * Well, formula is different, but the result is same.
784 		 * 8 byte fixed part for Type 0 Routing header, followed by
785 		 * gateway addresses
786 		 */
787 		optlen = 8 + gw_count * pr->addr_len;
788 	} else {
789 		optlen = 0;
790 	}
791 
792 	/* take care of the packet length calculations and checks */
793 	minpacket = pr->ip_hdr_len + sizeof (struct outdata) + optlen;
794 	if (useicmp)
795 		minpacket += pr->icmp_minlen;	/* minimum ICMP header size */
796 	else
797 		minpacket += sizeof (struct udphdr);
798 	plen = plen_input;
799 	if (plen == 0) {
800 		plen = minpacket;		/* minimum sized packet */
801 	} else if (minpacket > plen || plen > IP_MAXPACKET) {
802 		Fprintf(stderr, "%s: %s packet size must be >= %d and <= %d\n",
803 		    prog, pr->name, minpacket, IP_MAXPACKET);
804 		return (0);
805 	}
806 
807 	return (plen);
808 }
809 
810 /*
811  * Sets the source address by resolving -i and -s arguments, or if -i and -s
812  * don't dictate any, it sets the pick_src to make sure traceroute uses the
813  * kernel's pick of the source address.
814  * Returns number of interfaces configured on the source host, 0 on error or
815  * there's no interface which is up amd not a loopback.
816  */
817 static int
818 set_src_addr(struct pr_set *pr, struct ifaddrlist **alp)
819 {
820 	union any_in_addr *ap;
821 	struct ifaddrlist *al = NULL;
822 	struct ifaddrlist *tmp1_al = NULL;
823 	struct ifaddrlist *tmp2_al = NULL;
824 	/* LINTED E_BAD_PTR_CAST_ALIGN */
825 	struct sockaddr_in *sin_from = (struct sockaddr_in *)pr->from;
826 	/* LINTED E_BAD_PTR_CAST_ALIGN */
827 	struct sockaddr_in6 *sin6_from = (struct sockaddr_in6 *)pr->from;
828 	struct addrinfo *aip;
829 	char errbuf[ERRBUFSIZE];
830 	char temp_buf[INET6_ADDRSTRLEN];	/* use for inet_ntop() */
831 	int num_ifs;				/* all the interfaces  */
832 	int num_src_ifs;			/* exclude loopback and down */
833 	int i;
834 
835 	source = source_input;
836 
837 	/* get the interface address list */
838 	num_ifs = ifaddrlist(&al, pr->family, errbuf);
839 	if (num_ifs < 0) {
840 		Fprintf(stderr, "%s: ifaddrlist: %s\n", prog, errbuf);
841 		exit(EXIT_FAILURE);
842 	}
843 
844 	num_src_ifs = 0;
845 	for (i = 0; i < num_ifs; i++) {
846 		if (!(al[i].flags & IFF_LOOPBACK) && (al[i].flags & IFF_UP))
847 			num_src_ifs++;
848 	}
849 
850 	if (num_src_ifs == 0) {
851 		Fprintf(stderr, "%s: can't find any %s network interfaces\n",
852 		    prog, pr->name);
853 		return (0);
854 	}
855 
856 	/* verify the device */
857 	if (device != NULL) {
858 		tmp1_al = find_device(al, num_ifs, device);
859 
860 		if (tmp1_al == NULL) {
861 			Fprintf(stderr, "%s: %s (index %d) is an invalid %s"
862 			    " interface\n", prog, device, if_index, pr->name);
863 			free(al);
864 			return (0);
865 		}
866 	}
867 
868 	/* verify the source address */
869 	if (source != NULL) {
870 		get_hostinfo(source, pr->family, &aip);
871 		if (aip == NULL) {
872 			Fprintf(stderr,
873 			    "%s: %s is an invalid %s source address\n",
874 			    prog, source, pr->name);
875 
876 			free(al);
877 			return (0);
878 		}
879 
880 		source = aip->ai_canonname;
881 		ap = (union any_in_addr *)
882 		    /* LINTED E_BAD_PTR_CAST_ALIGN */
883 		    &((struct sockaddr_in6 *)
884 		    aip->ai_addr)->sin6_addr;
885 
886 		/*
887 		 * LBNL bug fixed: used to accept any src address
888 		 */
889 		tmp2_al = find_ifaddr(al, num_ifs, ap, pr->family);
890 
891 		if (tmp2_al == NULL) {
892 			Fprintf(stderr,
893 			    "%s: %s is an invalid %s source address\n", prog,
894 			    inet_ntop(pr->family, (const void *)ap,
895 				temp_buf, sizeof (temp_buf)),
896 			    pr->name);
897 
898 			free(al);
899 			freeaddrinfo(aip);
900 			return (0);
901 		}
902 	}
903 
904 	pick_src = _B_FALSE;
905 
906 	if (source == NULL) {			/* no -s used */
907 		if (device == NULL) {		/* no -i used, no -s used */
908 			pick_src = _B_TRUE;
909 		} else {			/* -i used, no -s used */
910 			/*
911 			 * -i used, but not -s, and it's IPv4: set the source
912 			 * address to whatever the interface has configured on
913 			 * it.
914 			 */
915 			if (pr->family == AF_INET)
916 				set_sin(pr->from, &(tmp1_al->addr), pr->family);
917 			else
918 				pick_src = _B_TRUE;
919 		}
920 	} else {				/* -s used */
921 		if (device == NULL) {		/* no -i used, -s used */
922 			set_sin(pr->from, ap, pr->family);
923 
924 			if (aip->ai_next != NULL) {
925 				Fprintf(stderr,
926 				    "%s: Warning: %s has multiple "
927 				    "addresses; using %s\n",
928 				    prog, source,
929 				    inet_ntop(pr->family,
930 					(const void *)pr->from_sin_addr,
931 					temp_buf, sizeof (temp_buf)));
932 			}
933 		} else {			/* -i and -s used */
934 			/*
935 			 * Make sure the source specified matches the
936 			 * interface address. You only care about this for IPv4
937 			 * IPv6 can handle IF not matching src address
938 			 */
939 			if (pr->family == AF_INET) {
940 				if (!has_addr(aip, &tmp1_al->addr)) {
941 					Fprintf(stderr,
942 					    "%s: %s is not on interface %s\n",
943 					    prog, source, device);
944 					exit(EXIT_FAILURE);
945 				}
946 				/*
947 				 * make sure we use the one matching the
948 				 * interface's address
949 				 */
950 				*ap = tmp1_al->addr;
951 			}
952 
953 			set_sin(pr->from, ap, pr->family);
954 		}
955 	}
956 
957 	/*
958 	 * Binding at this point will set the source address to be used
959 	 * for both IPv4 (when raw IP datagrams are not required) and
960 	 * IPv6.  If the address being bound to is zero, then the kernel
961 	 * will end up choosing the source address when the datagram is
962 	 * sent.
963 	 *
964 	 * For raw IPv4 datagrams, the source address is initialized
965 	 * within traceroute() along with the outbound destination
966 	 * address.
967 	 */
968 	if (pr->family == AF_INET && !raw_req) {
969 		sin_from->sin_family = AF_INET;
970 		sin_from->sin_port = htons(ident);
971 		if (bind(sndsock4, (struct sockaddr *)pr->from,
972 			sizeof (struct sockaddr_in)) < 0) {
973 			Fprintf(stderr, "%s: bind: %s\n", prog,
974 			    strerror(errno));
975 			exit(EXIT_FAILURE);
976 		}
977 	} else if (pr->family == AF_INET6) {
978 		sin6_from->sin6_family = AF_INET6;
979 		sin6_from->sin6_port = htons(ident);
980 		if (bind(sndsock6, (struct sockaddr *)pr->from,
981 			sizeof (struct sockaddr_in6)) < 0) {
982 			Fprintf(stderr, "%s: bind: %s\n", prog,
983 			    strerror(errno));
984 			exit(EXIT_FAILURE);
985 		}
986 
987 		whereto6.sin6_flowinfo = htonl((class << 20) | flow);
988 	}
989 	*alp = al;
990 	return (num_ifs);
991 }
992 
993 /*
994  * Returns the complete ifaddrlist structure matching the desired interface
995  * address. Ignores interfaces which are either down or loopback.
996  */
997 static struct ifaddrlist *
998 find_ifaddr(struct ifaddrlist *al, int len, union any_in_addr *addr,
999     int family)
1000 {
1001 	struct ifaddrlist *tmp_al = al;
1002 	int i;
1003 	size_t addr_len = (family == AF_INET) ? sizeof (struct in_addr) :
1004 	    sizeof (struct in6_addr);
1005 
1006 	for (i = 0; i < len; i++, tmp_al++) {
1007 		if ((!(tmp_al->flags & IFF_LOOPBACK) &&
1008 		    (tmp_al->flags & IFF_UP)) &&
1009 		    (memcmp(&tmp_al->addr, addr, addr_len) == 0))
1010 			break;
1011 	}
1012 
1013 	if (i < len) {
1014 		return (tmp_al);
1015 	} else {
1016 		return (NULL);
1017 	}
1018 }
1019 
1020 /*
1021  * Returns the complete ifaddrlist structure matching the desired interface name
1022  * Ignores interfaces which are either down or loopback.
1023  */
1024 static struct ifaddrlist *
1025 find_device(struct ifaddrlist *al, int len, char *device)
1026 {
1027 	struct ifaddrlist *tmp_al = al;
1028 	int i;
1029 
1030 	for (i = 0; i < len; i++, tmp_al++) {
1031 		if ((!(tmp_al->flags & IFF_LOOPBACK) &&
1032 		    (tmp_al->flags & IFF_UP)) &&
1033 		    (strcmp(tmp_al->device, device) == 0))
1034 			break;
1035 	}
1036 
1037 	if (i < len) {
1038 		return (tmp_al);
1039 	} else {
1040 		return (NULL);
1041 	}
1042 }
1043 
1044 /*
1045  * returns _B_TRUE if given hostinfo contains the given address
1046  */
1047 static boolean_t
1048 has_addr(struct addrinfo *ai, union any_in_addr *addr)
1049 {
1050 	struct addrinfo *ai_tmp = NULL;
1051 	union any_in_addr *ap;
1052 
1053 	for (ai_tmp = ai; ai_tmp != NULL; ai_tmp = ai_tmp->ai_next) {
1054 		if (ai_tmp->ai_family == AF_INET6)
1055 			continue;
1056 		ap = (union any_in_addr *)
1057 		    /* LINTED E_BAD_PTR_CAST_ALIGN */
1058 		    &((struct sockaddr_in *)ai_tmp->ai_addr)->sin_addr;
1059 		if (memcmp(ap, addr, sizeof (struct in_addr)) == 0)
1060 			break;
1061 	}
1062 
1063 	if (ai_tmp != NULL) {
1064 		return (_B_TRUE);
1065 	} else {
1066 		return (_B_FALSE);
1067 	}
1068 }
1069 
1070 /*
1071  * Resolve the gateway names, splitting results into v4 and v6 lists.
1072  * Gateway addresses are added to the appropriate passed-in array; the
1073  * number of resolved gateways for each af is returned in resolved[6].
1074  * Assumes that passed-in arrays are large enough for MAX_GWS[6] addrs
1075  * and resolved[6] ptrs are non-null; ignores array and counter if the
1076  * address family param makes them irrelevant.
1077  */
1078 static void
1079 get_gwaddrs(char **gwlist, int family, union any_in_addr *gwIPlist,
1080     union any_in_addr *gwIPlist6, int *resolved, int *resolved6)
1081 {
1082 	int i;
1083 	boolean_t check_v4 = _B_TRUE, check_v6 = _B_TRUE;
1084 	struct addrinfo *ai = NULL;
1085 	struct addrinfo *aip = NULL;
1086 
1087 	*resolved = *resolved6 = 0;
1088 	switch (family) {
1089 	case AF_UNSPEC:
1090 		break;
1091 	case AF_INET:
1092 		check_v6 = _B_FALSE;
1093 		break;
1094 	case AF_INET6:
1095 		check_v4 = _B_FALSE;
1096 		break;
1097 	default:
1098 		return;
1099 	}
1100 
1101 	if (check_v4 && gw_count >= MAX_GWS) {
1102 		check_v4 = _B_FALSE;
1103 		Fprintf(stderr, "%s: too many IPv4 gateways\n", prog);
1104 	}
1105 	if (check_v6 && gw_count >= MAX_GWS6) {
1106 		check_v6 = _B_FALSE;
1107 		Fprintf(stderr, "%s: too many IPv6 gateways\n", prog);
1108 	}
1109 
1110 	for (i = 0; i < gw_count; i++) {
1111 		if (!check_v4 && !check_v6)
1112 			return;
1113 		get_hostinfo(gwlist[i], family, &ai);
1114 		if (ai == NULL)
1115 			return;
1116 		if (check_v4 && num_v4 != 0) {
1117 			for (aip = ai; aip != NULL; aip = aip->ai_next) {
1118 				if (aip->ai_family == AF_INET) {
1119 					/* LINTED E_BAD_PTR_CAST_ALIGN */
1120 					bcopy(&((struct sockaddr_in *)
1121 					    aip->ai_addr)->sin_addr,
1122 					    &gwIPlist[i].addr,
1123 					    aip->ai_addrlen);
1124 					(*resolved)++;
1125 					break;
1126 				}
1127 			}
1128 		} else if (check_v4) {
1129 			check_v4 = _B_FALSE;
1130 		}
1131 		if (check_v6 && num_v6 != 0) {
1132 			for (aip = ai; aip != NULL; aip = aip->ai_next) {
1133 				if (aip->ai_family == AF_INET6) {
1134 					/* LINTED E_BAD_PTR_CAST_ALIGN */
1135 					bcopy(&((struct sockaddr_in6 *)
1136 					    aip->ai_addr)->sin6_addr,
1137 					    &gwIPlist6[i].addr6,
1138 					    aip->ai_addrlen);
1139 					(*resolved6)++;
1140 					break;
1141 				}
1142 			}
1143 		} else if (check_v6) {
1144 			check_v6 = _B_FALSE;
1145 		}
1146 	}
1147 	freeaddrinfo(ai);
1148 }
1149 
1150 /*
1151  * set protocol specific values here
1152  */
1153 static void
1154 setup_protocol(struct pr_set *pr, int family)
1155 {
1156 	/*
1157 	 * Set the global variables for each AF. This is going to save us lots
1158 	 * of "if (family == AF_INET)... else .."
1159 	 */
1160 	pr->family = family;
1161 
1162 	if (family == AF_INET) {
1163 		if (!docksum) {
1164 			Fprintf(stderr,
1165 			    "%s: Warning: checksums disabled\n", prog);
1166 		}
1167 		(void) strcpy(pr->name, "IPv4");
1168 		(void) strcpy(pr->icmp, "icmp");
1169 		pr->icmp_minlen = ICMP_MINLEN;
1170 		pr->addr_len = sizeof (struct in_addr);
1171 		pr->ip_hdr_len = sizeof (struct ip);
1172 		pr->sock_size = sizeof (struct sockaddr_in);
1173 		pr->to = (struct sockaddr *)&whereto;
1174 		pr->from = (struct sockaddr *)&wherefrom;
1175 		pr->from_sin_addr = (void *)&wherefrom.sin_addr;
1176 		pr->gwIPlist = gwIPlist;
1177 		pr->set_buffers_fn = set_buffers;
1178 		pr->check_reply_fn = check_reply;
1179 		pr->print_icmp_other_fn = print_icmp_other;
1180 		pr->print_addr_fn = print_addr;
1181 		pr->packlen = calc_packetlen(packlen_input, pr);
1182 	} else {
1183 		(void) strcpy(pr->name, "IPv6");
1184 		(void) strcpy(pr->icmp, "ipv6-icmp");
1185 		pr->icmp_minlen = ICMP6_MINLEN;
1186 		pr->addr_len = sizeof (struct in6_addr);
1187 		pr->ip_hdr_len = sizeof (struct ip6_hdr);
1188 		pr->sock_size = sizeof (struct sockaddr_in6);
1189 		pr->to = (struct sockaddr *)&whereto6;
1190 		pr->from = (struct sockaddr *)&wherefrom6;
1191 		pr->from_sin_addr = (void *)&wherefrom6.sin6_addr;
1192 		pr->gwIPlist = gwIP6list;
1193 		pr->set_buffers_fn = set_buffers6;
1194 		pr->check_reply_fn = check_reply6;
1195 		pr->print_icmp_other_fn = print_icmp_other6;
1196 		pr->print_addr_fn = print_addr6;
1197 		pr->packlen = calc_packetlen(packlen_input, pr);
1198 	}
1199 	if (pr->packlen == 0)
1200 		exit(EXIT_FAILURE);
1201 }
1202 
1203 /*
1204  * setup the sockets for the given protocol's address family
1205  */
1206 static void
1207 setup_socket(struct pr_set *pr, int packet_len)
1208 {
1209 	int on = 1;
1210 	struct protoent *pe;
1211 	int type;
1212 	int proto;
1213 	int int_op;
1214 	int rsock;
1215 	int ssock;
1216 
1217 	if ((pe = getprotobyname(pr->icmp)) == NULL) {
1218 		Fprintf(stderr, "%s: unknown protocol %s\n", prog, pr->icmp);
1219 		exit(EXIT_FAILURE);
1220 	}
1221 
1222 	/* privilege bracketing */
1223 	(void) __priv_bracket(PRIV_ON);
1224 
1225 	if ((rsock = socket(pr->family, SOCK_RAW, pe->p_proto)) < 0) {
1226 		Fprintf(stderr, "%s: icmp socket: %s\n", prog, strerror(errno));
1227 		exit(EXIT_FAILURE);
1228 	}
1229 
1230 	if (options & SO_DEBUG) {
1231 		if (setsockopt(rsock, SOL_SOCKET, SO_DEBUG, (char *)&on,
1232 		    sizeof (on)) < 0) {
1233 			Fprintf(stderr, "%s: SO_DEBUG: %s\n", prog,
1234 			    strerror(errno));
1235 			exit(EXIT_FAILURE);
1236 		}
1237 	}
1238 	if (options & SO_DONTROUTE) {
1239 		if (setsockopt(rsock, SOL_SOCKET, SO_DONTROUTE, (char *)&on,
1240 		    sizeof (on)) < 0) {
1241 			Fprintf(stderr, "%s: SO_DONTROUTE: %s\n", prog,
1242 			    strerror(errno));
1243 			exit(EXIT_FAILURE);
1244 		}
1245 	}
1246 
1247 	if (pr->family == AF_INET6) {
1248 		/* Enable receipt of destination address info */
1249 		if (setsockopt(rsock, IPPROTO_IPV6, IPV6_RECVPKTINFO,
1250 		    (char *)&on, sizeof (on)) < 0) {
1251 			Fprintf(stderr, "%s: IPV6_RECVPKTINFO: %s\n", prog,
1252 			    strerror(errno));
1253 			exit(EXIT_FAILURE);
1254 		}
1255 		/* Enable receipt of hoplimit info */
1256 		if (setsockopt(rsock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT,
1257 		    (char *)&on, sizeof (on)) < 0) {
1258 			Fprintf(stderr, "%s: IPV6_RECVHOPLIMIT: %s\n", prog,
1259 			    strerror(errno));
1260 			exit(EXIT_FAILURE);
1261 		}
1262 
1263 	}
1264 
1265 	/*
1266 	 * Initialize the socket type and protocol based on the address
1267 	 * family, whether or not a raw IP socket is required (for IPv4)
1268 	 * or whether ICMP will be used instead of UDP.
1269 	 *
1270 	 * For historical reasons, the datagrams sent out by
1271 	 * traceroute(1M) do not have the "don't fragment" flag set.  For
1272 	 * this reason as well as the ability to set the Loose Source and
1273 	 * Record Route (LSRR) option, a raw IP socket will be used for
1274 	 * IPv4 when run in the global zone.  Otherwise, the actual
1275 	 * datagram that will be sent will be a regular UDP or ICMP echo
1276 	 * request packet.  However for convenience and for future options
1277 	 * when other IP header information may be specified using
1278 	 * traceroute, the buffer including the raw IP and UDP or ICMP
1279 	 * header is always filled in.  When the probe is actually sent,
1280 	 * the size of the request and the start of the packet is set
1281 	 * according to the type of datagram to send.
1282 	 */
1283 	if (pr->family == AF_INET && raw_req) {
1284 		type = SOCK_RAW;
1285 		proto = IPPROTO_RAW;
1286 	} else if (useicmp) {
1287 		type = SOCK_RAW;
1288 		if (pr->family == AF_INET)
1289 			proto = IPPROTO_ICMP;
1290 		else
1291 			proto = IPPROTO_ICMPV6;
1292 	} else {
1293 		type = SOCK_DGRAM;
1294 		proto = IPPROTO_UDP;
1295 	}
1296 	ssock = socket(pr->family, type, proto);
1297 
1298 	if (ssock < 0) {
1299 		if (proto == IPPROTO_RAW) {
1300 			Fprintf(stderr, "%s: raw socket: %s\n", prog,
1301 			    strerror(errno));
1302 		} else if (proto == IPPROTO_UDP) {
1303 			Fprintf(stderr, "%s: udp socket: %s\n", prog,
1304 			    strerror(errno));
1305 		} else {
1306 			Fprintf(stderr, "%s: icmp socket: %s\n", prog,
1307 			    strerror(errno));
1308 		}
1309 		exit(EXIT_FAILURE);
1310 	}
1311 
1312 	if (setsockopt(ssock, SOL_SOCKET, SO_SNDBUF, (char *)&packet_len,
1313 	    sizeof (packet_len)) < 0) {
1314 		Fprintf(stderr, "%s: SO_SNDBUF: %s\n", prog, strerror(errno));
1315 		exit(EXIT_FAILURE);
1316 	}
1317 
1318 	if (pr->family == AF_INET && raw_req) {
1319 		if (setsockopt(ssock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
1320 		    sizeof (on)) < 0) {
1321 			Fprintf(stderr, "%s: IP_HDRINCL: %s\n", prog,
1322 			    strerror(errno));
1323 			exit(EXIT_FAILURE);
1324 		}
1325 	}
1326 
1327 	if (options & SO_DEBUG) {
1328 		if (setsockopt(ssock, SOL_SOCKET, SO_DEBUG, (char *)&on,
1329 		    sizeof (on)) < 0) {
1330 			Fprintf(stderr, "%s: SO_DEBUG: %s\n", prog,
1331 			    strerror(errno));
1332 			exit(EXIT_FAILURE);
1333 		}
1334 	}
1335 	if (options & SO_DONTROUTE) {
1336 		if (setsockopt(ssock, SOL_SOCKET, SO_DONTROUTE,
1337 		    (char *)&on, sizeof (on)) < 0) {
1338 			Fprintf(stderr, "%s: SO_DONTROUTE: %s\n", prog,
1339 			    strerror(errno));
1340 			exit(EXIT_FAILURE);
1341 		}
1342 	}
1343 
1344 	/*
1345 	 * If a raw IPv4 packet is going to be sent, the Type of Service
1346 	 * field in the packet will be initialized in set_buffers().
1347 	 * Otherwise, it is initialized here using the IPPROTO_IP level
1348 	 * socket option.
1349 	 */
1350 	if (settos && !raw_req) {
1351 		int_op = tos;
1352 		if (setsockopt(ssock, IPPROTO_IP, IP_TOS, (char *)&int_op,
1353 		    sizeof (int_op)) < 0) {
1354 			Fprintf(stderr, "%s: IP_TOS: %s\n", prog,
1355 			    strerror(errno));
1356 			exit(EXIT_FAILURE);
1357 		}
1358 	}
1359 	if (pr->family == AF_INET) {
1360 		rcvsock4 = rsock;
1361 		sndsock4 = ssock;
1362 	} else {
1363 		rcvsock6 = rsock;
1364 		sndsock6 = ssock;
1365 	}
1366 	/* Revert to non-privileged user after configuring sockets */
1367 	(void) __priv_bracket(PRIV_OFF);
1368 }
1369 
1370 /*
1371  * If we are "probing all", this function calls traceroute() for each IP address
1372  * of the target, otherwise calls only once. Returns _B_FALSE if traceroute()
1373  * fails.
1374  */
1375 static void
1376 trace_it(struct addrinfo *ai_dst)
1377 {
1378 	struct msghdr msg6;
1379 	int num_dst_IPaddrs;
1380 	struct addrinfo *aip;
1381 	int i;
1382 
1383 	if (!probe_all)
1384 		num_dst_IPaddrs = 1;
1385 	else
1386 		num_dst_IPaddrs = num_v4 + num_v6;
1387 
1388 	/*
1389 	 * Initialize the msg6 structure using the hoplimit for the first
1390 	 * probe packet, gateway addresses and the outgoing interface index.
1391 	 */
1392 	if (ai_dst->ai_family == AF_INET6 || (probe_all && num_v6)) {
1393 		msg6.msg_control = NULL;
1394 		msg6.msg_controllen = 0;
1395 		set_ancillary_data(&msg6, first_ttl, pr6->gwIPlist, gw_count,
1396 		    if_index);
1397 	}
1398 
1399 	/* run traceroute for all the IP addresses of the multihomed dest */
1400 	for (aip = ai_dst, i = 0; i < num_dst_IPaddrs && aip != NULL; i++) {
1401 		union any_in_addr *addrp;
1402 		if (aip->ai_family == AF_INET) {
1403 			addrp = (union any_in_addr *)
1404 			    /* LINTED E_BAD_PTR_CAST_ALIGN */
1405 			    &((struct sockaddr_in *)
1406 			    aip->ai_addr)->sin_addr;
1407 			set_sin((struct sockaddr *)pr4->to, addrp,
1408 			    aip->ai_family);
1409 			traceroute(addrp, &msg6, pr4, num_ifs4, al4);
1410 		} else {
1411 			addrp = (union any_in_addr *)
1412 			    /* LINTED E_BAD_PTR_CAST_ALIGN */
1413 			    &((struct sockaddr_in6 *)
1414 			    aip->ai_addr)->sin6_addr;
1415 			set_sin((struct sockaddr *)pr6->to, addrp,
1416 			    aip->ai_family);
1417 			traceroute(addrp, &msg6, pr6, num_ifs6, al6);
1418 		}
1419 		aip = aip->ai_next;
1420 		if (i < (num_dst_IPaddrs - 1))
1421 			(void) putchar('\n');
1422 	}
1423 }
1424 
1425 /*
1426  * set the IP address in a sockaddr struct
1427  */
1428 static void
1429 set_sin(struct sockaddr *sock, union any_in_addr *addr, int family)
1430 {
1431 	sock->sa_family = family;
1432 
1433 	if (family == AF_INET)
1434 		/* LINTED E_BAD_PTR_CAST_ALIGN */
1435 		((struct sockaddr_in *)sock)->sin_addr = addr->addr;
1436 	else
1437 		/* LINTED E_BAD_PTR_CAST_ALIGN */
1438 		((struct sockaddr_in6 *)sock)->sin6_addr = addr->addr6;
1439 }
1440 
1441 /*
1442  * returns the IF name on which the given IP address is configured
1443  */
1444 static char *
1445 device_name(struct ifaddrlist *al, int len, union any_in_addr *ip_addr,
1446     struct pr_set *pr)
1447 {
1448 	int i;
1449 	struct ifaddrlist *tmp_al;
1450 
1451 	tmp_al = al;
1452 
1453 	for (i = 0; i < len; i++, tmp_al++) {
1454 		if (memcmp(&tmp_al->addr, ip_addr, pr->addr_len) == 0) {
1455 			return (tmp_al->device);
1456 		}
1457 	}
1458 
1459 	return (NULL);
1460 }
1461 
1462 /*
1463  * Trace the route to the host with given IP address.
1464  */
1465 static void
1466 traceroute(union any_in_addr *ip_addr, struct msghdr *msg6, struct pr_set *pr,
1467     int num_ifs, struct ifaddrlist *al)
1468 {
1469 	int ttl;
1470 	int probe;
1471 	uchar_t type;				/* icmp type */
1472 	uchar_t code;				/* icmp code */
1473 	int reply;
1474 	int seq = 0;
1475 	char temp_buf[INET6_ADDRSTRLEN];	/* use for inet_ntop() */
1476 	int longjmp_return;			/* return value from longjump */
1477 	struct ip *ip = (struct ip *)packet;
1478 	boolean_t got_there = _B_FALSE;		/* we hit the destination */
1479 	static boolean_t first_pkt = _B_TRUE;
1480 	int hoplimit;				/* hoplimit for IPv6 packets */
1481 	struct in6_addr addr6;
1482 	int num_src_ifs;			/* excludes down and loopback */
1483 	struct msghdr in_msg;
1484 	struct iovec iov;
1485 	int *intp;
1486 	int sndsock;
1487 	int rcvsock;
1488 
1489 	msg6->msg_name = pr->to;
1490 	msg6->msg_namelen = sizeof (struct sockaddr_in6);
1491 	sndsock =  (pr->family == AF_INET) ? sndsock4 : sndsock6;
1492 	rcvsock =  (pr->family == AF_INET) ? rcvsock4 : rcvsock6;
1493 
1494 	/* carry out the source address selection */
1495 	if (pick_src) {
1496 		union any_in_addr src_addr;
1497 		char *dev_name;
1498 		int i;
1499 
1500 		/*
1501 		 * If there's a gateway, a routing header as a consequence, our
1502 		 * kernel picks the source address based on the first hop
1503 		 * address, rather than final destination address.
1504 		 */
1505 		if (gw_count > 0) {
1506 			(void) select_src_addr(pr->gwIPlist, &src_addr,
1507 			    pr->family);
1508 		} else {
1509 			(void) select_src_addr(ip_addr, &src_addr, pr->family);
1510 		}
1511 		set_sin(pr->from, &src_addr, pr->family);
1512 
1513 		/* filter out down and loopback interfaces */
1514 		num_src_ifs = 0;
1515 		for (i = 0; i < num_ifs; i++) {
1516 			if (!(al[i].flags & IFF_LOOPBACK) &&
1517 			    (al[i].flags & IFF_UP))
1518 				num_src_ifs++;
1519 		}
1520 
1521 		if (num_src_ifs > 1) {
1522 			dev_name = device_name(al, num_ifs, &src_addr, pr);
1523 			if (dev_name == NULL)
1524 				dev_name = "?";
1525 
1526 			Fprintf(stderr,
1527 			    "%s: Warning: Multiple interfaces found;"
1528 			    " using %s @ %s\n",
1529 			    prog, inet_ntop(pr->family,
1530 				(const void *)pr->from_sin_addr,
1531 				temp_buf, sizeof (temp_buf)),
1532 			    dev_name);
1533 		}
1534 	}
1535 
1536 	if (pr->family == AF_INET) {
1537 		outip4->ip_src = *(struct in_addr *)pr->from_sin_addr;
1538 		outip4->ip_dst = ip_addr->addr;
1539 	}
1540 
1541 	/*
1542 	 * If the hostname is an IPv6 literal address, let's not print it twice.
1543 	 */
1544 	if (pr->family == AF_INET6 &&
1545 	    inet_pton(AF_INET6, hostname, &addr6) > 0) {
1546 		Fprintf(stderr, "%s to %s", prog, hostname);
1547 	} else {
1548 		Fprintf(stderr, "%s to %s (%s)", prog, hostname,
1549 		    inet_ntop(pr->family, (const void *)ip_addr, temp_buf,
1550 			sizeof (temp_buf)));
1551 	}
1552 
1553 	if (source)
1554 		Fprintf(stderr, " from %s", source);
1555 	Fprintf(stderr, ", %d hops max, %d byte packets\n", max_ttl,
1556 	    pr->packlen);
1557 	(void) fflush(stderr);
1558 
1559 	/*
1560 	 * Setup the source routing for IPv4. For IPv6, we did the required
1561 	 * setup in the caller function, trace_it(), because it's independent
1562 	 * from the IP address of target.
1563 	 */
1564 	if (pr->family == AF_INET && gw_count > 0)
1565 		set_IPv4opt_sourcerouting(sndsock, ip_addr, pr->gwIPlist);
1566 
1567 	if (probe_all) {
1568 		/* interrupt handler sig_handler() jumps back to here */
1569 		if ((longjmp_return = setjmp(env)) != 0) {
1570 			switch (longjmp_return) {
1571 			case SIGINT:
1572 				Printf("(skipping)\n");
1573 				return;
1574 			case SIGQUIT:
1575 				Printf("(exiting)\n");
1576 				exit(EXIT_SUCCESS);
1577 			default:	/* should never happen */
1578 				exit(EXIT_FAILURE);
1579 			}
1580 		}
1581 		(void) signal(SIGINT, sig_handler);
1582 	}
1583 
1584 	for (ttl = first_ttl; ttl <= max_ttl; ++ttl) {
1585 		union any_in_addr lastaddr;
1586 		int timeouts = 0;
1587 		double rtt;		/* for statistics */
1588 		int nreceived = 0;
1589 		double rttmin, rttmax;
1590 		double rttsum, rttssq;
1591 		int unreachable;
1592 
1593 		got_there = _B_FALSE;
1594 		unreachable = 0;
1595 
1596 		/*
1597 		 * The following line clears both IPv4 and IPv6 address stored
1598 		 * in the union.
1599 		 */
1600 		lastaddr.addr6 = in6addr_any;
1601 
1602 		if ((ttl == (first_ttl + 1)) && (options & SO_DONTROUTE)) {
1603 			Fprintf(stderr,
1604 			    "%s: host %s is not on a directly-attached"
1605 			    " network\n", prog, hostname);
1606 			break;
1607 		}
1608 
1609 		Printf("%2d ", ttl);
1610 		(void) fflush(stdout);
1611 
1612 		for (probe = 0; (probe < nprobes) && (timeouts < max_timeout);
1613 		    ++probe) {
1614 			int cc;
1615 			struct timeval t1, t2;
1616 
1617 			/*
1618 			 * Put a delay before sending this probe packet. Don't
1619 			 * delay it if it's the very first packet.
1620 			 */
1621 			if (!first_pkt) {
1622 				if (delay.tv_sec > 0)
1623 					(void) sleep((uint_t)delay.tv_sec);
1624 				if (delay.tv_usec > 0)
1625 					(void) usleep(delay.tv_usec);
1626 			} else {
1627 				first_pkt = _B_FALSE;
1628 			}
1629 
1630 			(void) gettimeofday(&t1, NULL);
1631 
1632 			if (pr->family == AF_INET) {
1633 				send_probe(sndsock, pr->to, outip4, seq, ttl,
1634 				    &t1, pr->packlen);
1635 			} else {
1636 				send_probe6(sndsock, msg6, outip6, seq, ttl,
1637 				    &t1, pr->packlen);
1638 			}
1639 
1640 			/* prepare msghdr for recvmsg() */
1641 			in_msg.msg_name = pr->from;
1642 			in_msg.msg_namelen = pr->sock_size;
1643 
1644 			iov.iov_base = (char *)packet;
1645 			iov.iov_len = sizeof (packet);
1646 
1647 			in_msg.msg_iov = &iov;
1648 			in_msg.msg_iovlen = 1;
1649 
1650 			in_msg.msg_control = ancillary_data;
1651 			in_msg.msg_controllen = sizeof (ancillary_data);
1652 
1653 			while ((cc = wait_for_reply(rcvsock, &in_msg,
1654 			    &t1)) != 0) {
1655 				(void) gettimeofday(&t2, NULL);
1656 
1657 				reply = (*pr->check_reply_fn) (&in_msg, cc, seq,
1658 				    &type, &code);
1659 
1660 				in_msg.msg_controllen =
1661 				    sizeof (ancillary_data);
1662 				/* Skip short packet */
1663 				if (reply == REPLY_SHORT_PKT) {
1664 					continue;
1665 				}
1666 
1667 				timeouts = 0;
1668 
1669 				/*
1670 				 * if reply comes from a different host, print
1671 				 * the hostname
1672 				 */
1673 				if (memcmp(pr->from_sin_addr, &lastaddr,
1674 				    pr->addr_len) != 0) {
1675 					(*pr->print_addr_fn) ((uchar_t *)packet,
1676 					    cc, pr->from);
1677 					/* store the address response */
1678 					(void) memcpy(&lastaddr,
1679 					    pr->from_sin_addr, pr->addr_len);
1680 				}
1681 
1682 				rtt = deltaT(&t1, &t2);
1683 				if (collect_stat) {
1684 					record_stats(rtt, &nreceived, &rttmin,
1685 					    &rttmax, &rttsum, &rttssq);
1686 				} else {
1687 					Printf("  %.3f ms", rtt);
1688 				}
1689 
1690 				if (pr->family == AF_INET6) {
1691 					intp =
1692 					    (int *)find_ancillary_data(&in_msg,
1693 						IPPROTO_IPV6, IPV6_HOPLIMIT);
1694 					if (intp == NULL) {
1695 						Fprintf(stderr,
1696 						    "%s: can't find "
1697 						    "IPV6_HOPLIMIT ancillary "
1698 						    "data\n", prog);
1699 						exit(EXIT_FAILURE);
1700 					}
1701 					hoplimit = *intp;
1702 				}
1703 
1704 				if (reply == REPLY_GOT_TARGET) {
1705 					got_there = _B_TRUE;
1706 
1707 					if (((pr->family == AF_INET) &&
1708 					    (ip->ip_ttl <= 1)) ||
1709 					    ((pr->family == AF_INET6) &&
1710 					    (hoplimit <= 1)))
1711 						Printf(" !");
1712 				}
1713 
1714 				if (!collect_stat && showttl) {
1715 					if (pr->family == AF_INET) {
1716 						Printf(" (ttl=%d)",
1717 						    (int)ip->ip_ttl);
1718 					} else if (hoplimit != -1) {
1719 						Printf(" (hop limit=%d)",
1720 						    hoplimit);
1721 					}
1722 				}
1723 
1724 				if (reply == REPLY_GOT_OTHER) {
1725 					if ((*pr->print_icmp_other_fn)
1726 					    (type, code)) {
1727 						unreachable++;
1728 					}
1729 				}
1730 
1731 				/* special case */
1732 				if (pr->family == AF_INET &&
1733 				    type == ICMP_UNREACH &&
1734 				    code == ICMP_UNREACH_PROTOCOL)
1735 					got_there = _B_TRUE;
1736 
1737 				break;
1738 			}
1739 
1740 			seq = (seq + 1) % (MAX_SEQ + 1);
1741 
1742 			if (cc == 0) {
1743 				Printf(" *");
1744 				timeouts++;
1745 			}
1746 
1747 			(void) fflush(stdout);
1748 		}
1749 
1750 		if (collect_stat) {
1751 			print_stats(probe, nreceived, rttmin, rttmax, rttsum,
1752 			    rttssq);
1753 		}
1754 
1755 		(void) putchar('\n');
1756 
1757 		/* either we hit the target or received too many unreachables */
1758 		if (got_there ||
1759 		    (unreachable > 0 && unreachable >= nprobes - 1))
1760 			break;
1761 	}
1762 
1763 	/* Ignore the SIGINT between traceroute() runs */
1764 	if (probe_all)
1765 		(void) signal(SIGINT, SIG_IGN);
1766 }
1767 
1768 /*
1769  * for a given destination address and address family, it finds out what
1770  * source address kernel is going to pick
1771  */
1772 static void
1773 select_src_addr(union any_in_addr *dst_addr, union any_in_addr *src_addr,
1774     int family)
1775 {
1776 	int tmp_fd;
1777 	struct sockaddr *sock;
1778 	struct sockaddr_in *sin;
1779 	struct sockaddr_in6 *sin6;
1780 	size_t sock_len;
1781 
1782 	sock = (struct sockaddr *)malloc(sizeof (struct sockaddr_in6));
1783 	if (sock == NULL) {
1784 		Fprintf(stderr, "%s: malloc %s\n", prog, strerror(errno));
1785 		exit(EXIT_FAILURE);
1786 	}
1787 	(void) bzero(sock, sizeof (struct sockaddr_in6));
1788 
1789 	if (family == AF_INET) {
1790 		/* LINTED E_BAD_PTR_CAST_ALIGN */
1791 		sin = (struct sockaddr_in *)sock;
1792 		sin->sin_family = AF_INET;
1793 		sin->sin_addr = dst_addr->addr;
1794 		sin->sin_port = IPPORT_ECHO;	/* port shouldn't be 0 */
1795 		sock_len = sizeof (struct sockaddr_in);
1796 	} else {
1797 		/* LINTED E_BAD_PTR_CAST_ALIGN */
1798 		sin6 = (struct sockaddr_in6 *)sock;
1799 		sin6->sin6_family = AF_INET6;
1800 		sin6->sin6_addr = dst_addr->addr6;
1801 		sin6->sin6_port = IPPORT_ECHO;	/* port shouldn't be 0 */
1802 		sock_len = sizeof (struct sockaddr_in6);
1803 	}
1804 
1805 	/* open a UDP socket */
1806 	if ((tmp_fd = socket(family, SOCK_DGRAM, 0)) < 0) {
1807 		Fprintf(stderr, "%s: udp socket: %s\n", prog,
1808 		    strerror(errno));
1809 		exit(EXIT_FAILURE);
1810 	}
1811 
1812 	/* connect it */
1813 	if (connect(tmp_fd, sock, sock_len) < 0) {
1814 		/*
1815 		 * If there's no route to the destination, this connect() call
1816 		 * fails. We just return all-zero (wildcard) as the source
1817 		 * address, so that user can get to see "no route to dest"
1818 		 * message, as it'll try to send the probe packet out and will
1819 		 * receive ICMP unreachable.
1820 		 */
1821 		if (family == AF_INET)
1822 			src_addr->addr.s_addr = INADDR_ANY;
1823 		else
1824 			src_addr->addr6 = in6addr_any;
1825 		free(sock);
1826 		return;
1827 	}
1828 
1829 	/* get the local sock info */
1830 	if (getsockname(tmp_fd, sock, &sock_len) < 0) {
1831 		Fprintf(stderr, "%s: getsockname: %s\n", prog,
1832 		    strerror(errno));
1833 		exit(EXIT_FAILURE);
1834 	}
1835 
1836 	if (family == AF_INET) {
1837 		/* LINTED E_BAD_PTR_CAST_ALIGN */
1838 		sin = (struct sockaddr_in *)sock;
1839 		src_addr->addr = sin->sin_addr;
1840 	} else {
1841 		/* LINTED E_BAD_PTR_CAST_ALIGN */
1842 		sin6 = (struct sockaddr_in6 *)sock;
1843 		src_addr->addr6 = sin6->sin6_addr;
1844 	}
1845 
1846 	free(sock);
1847 	(void) close(tmp_fd);
1848 }
1849 
1850 /*
1851  * Checksum routine for Internet Protocol family headers (C Version)
1852  */
1853 ushort_t
1854 in_cksum(ushort_t *addr, int len)
1855 {
1856 	int nleft = len;
1857 	ushort_t *w = addr;
1858 	ushort_t answer;
1859 	int sum = 0;
1860 
1861 	/*
1862 	 *  Our algorithm is simple, using a 32 bit accumulator (sum),
1863 	 *  we add sequential 16 bit words to it, and at the end, fold
1864 	 *  back all the carry bits from the top 16 bits into the lower
1865 	 *  16 bits.
1866 	 */
1867 	while (nleft > 1)  {
1868 		sum += *w++;
1869 		nleft -= 2;
1870 	}
1871 
1872 	/* mop up an odd byte, if necessary */
1873 	if (nleft == 1)
1874 		sum += *(uchar_t *)w;
1875 
1876 	/* add back carry outs from top 16 bits to low 16 bits */
1877 	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
1878 	sum += (sum >> 16);			/* add carry */
1879 	answer = ~sum;				/* truncate to 16 bits */
1880 	return (answer);
1881 }
1882 
1883 /*
1884  * Wait until a reply arrives or timeout occurs. If packet arrived, read it
1885  * return the size of the packet read.
1886  */
1887 static int
1888 wait_for_reply(int sock, struct msghdr *msg, struct timeval *tp)
1889 {
1890 	fd_set fds;
1891 	struct timeval now, wait;
1892 	int cc = 0;
1893 	int result;
1894 
1895 	(void) FD_ZERO(&fds);
1896 	FD_SET(sock, &fds);
1897 
1898 	wait.tv_sec = tp->tv_sec + waittime;
1899 	wait.tv_usec = tp->tv_usec;
1900 	(void) gettimeofday(&now, NULL);
1901 	tv_sub(&wait, &now);
1902 
1903 	if (wait.tv_sec < 0 || wait.tv_usec < 0)
1904 		return (0);
1905 
1906 	result = select(sock + 1, &fds, (fd_set *)NULL, (fd_set *)NULL, &wait);
1907 
1908 	if (result == -1) {
1909 		if (errno != EINTR) {
1910 			Fprintf(stderr, "%s: select: %s\n", prog,
1911 			    strerror(errno));
1912 		}
1913 	} else if (result > 0)
1914 		cc = recvmsg(sock, msg, 0);
1915 
1916 	return (cc);
1917 }
1918 
1919 /*
1920  * Construct an Internet address representation. If the nflag has been supplied,
1921  * give numeric value, otherwise try for symbolic name.
1922  */
1923 char *
1924 inet_name(union any_in_addr *in, int family)
1925 {
1926 	char *cp;
1927 	static boolean_t first = _B_TRUE;
1928 	static char domain[NI_MAXHOST + 1];
1929 	static char line[NI_MAXHOST + 1];	/* assuming		*/
1930 				/* (NI_MAXHOST + 1) >= INET6_ADDRSTRLEN */
1931 	char hbuf[NI_MAXHOST];
1932 	socklen_t slen;
1933 	struct sockaddr_in sin;
1934 	struct sockaddr_in6 sin6;
1935 	struct sockaddr *sa;
1936 	int flags;
1937 
1938 	switch (family) {
1939 	case AF_INET:
1940 		slen = sizeof (struct sockaddr_in);
1941 		sin.sin_addr = in->addr;
1942 		sin.sin_port = 0;
1943 		sa = (struct sockaddr *)&sin;
1944 		break;
1945 	case AF_INET6:
1946 		slen = sizeof (struct sockaddr_in6);
1947 		sin6.sin6_addr = in->addr6;
1948 		sin6.sin6_port = 0;
1949 		sa = (struct sockaddr *)&sin6;
1950 		break;
1951 	deafult:
1952 		(void) snprintf(line, sizeof (line),
1953 		    "<invalid address family>");
1954 		return (line);
1955 	}
1956 	sa->sa_family = family;
1957 
1958 	if (first && !nflag) {
1959 		/* find out the domain name */
1960 		first = _B_FALSE;
1961 		if (gethostname(domain, MAXHOSTNAMELEN) == 0 &&
1962 		    (cp = strchr(domain, '.')) != NULL) {
1963 			(void) strncpy(domain, cp + 1, sizeof (domain) - 1);
1964 			domain[sizeof (domain) - 1] = '\0';
1965 		} else {
1966 			domain[0] = '\0';
1967 		}
1968 	}
1969 
1970 	flags = (nflag) ? NI_NUMERICHOST : NI_NAMEREQD;
1971 	if (getnameinfo(sa, slen, hbuf, sizeof (hbuf), NULL, 0, flags) != 0) {
1972 		if (inet_ntop(family, (const void *)&in->addr6,
1973 		    hbuf, sizeof (hbuf)) == NULL)
1974 			hbuf[0] = 0;
1975 	} else if (!nflag && (cp = strchr(hbuf, '.')) != NULL &&
1976 	    strcmp(cp + 1, domain) == 0) {
1977 		*cp = '\0';
1978 	}
1979 	(void) strlcpy(line, hbuf, sizeof (line));
1980 
1981 	return (line);
1982 }
1983 
1984 /*
1985  * return the difference (in msec) between two time values
1986  */
1987 static double
1988 deltaT(struct timeval *t1p, struct timeval *t2p)
1989 {
1990 	double dt;
1991 
1992 	dt = (double)(t2p->tv_sec - t1p->tv_sec) * 1000.0 +
1993 	    (double)(t2p->tv_usec - t1p->tv_usec) / 1000.0;
1994 	return (dt);
1995 }
1996 
1997 /*
1998  * Subtract 2 timeval structs:  out = out - in.
1999  * Out is assumed to be >= in.
2000  */
2001 static void
2002 tv_sub(struct timeval *out, struct timeval *in)
2003 {
2004 	if ((out->tv_usec -= in->tv_usec) < 0)   {
2005 		--out->tv_sec;
2006 		out->tv_usec += 1000000;
2007 	}
2008 	out->tv_sec -= in->tv_sec;
2009 }
2010 
2011 /*
2012  * record statistics
2013  */
2014 static void
2015 record_stats(double rtt, int *nreceived, double *rttmin, double *rttmax,
2016     double *rttsum, double *rttssq)
2017 {
2018 	if (*nreceived == 0) {
2019 		*rttmin = rtt;
2020 		*rttmax = rtt;
2021 		*rttsum = rtt;
2022 		*rttssq = rtt * rtt;
2023 	} else {
2024 		if (rtt < *rttmin)
2025 			*rttmin = rtt;
2026 
2027 		if (rtt > *rttmax)
2028 			*rttmax = rtt;
2029 
2030 		*rttsum += rtt;
2031 		*rttssq += rtt * rtt;
2032 	}
2033 
2034 	(*nreceived)++;
2035 }
2036 
2037 /*
2038  * display statistics
2039  */
2040 static void
2041 print_stats(int ntransmitted, int nreceived, double rttmin, double rttmax,
2042     double rttsum, double rttssq)
2043 {
2044 	double rttavg;			/* average round-trip time */
2045 	double rttstd;			/* rtt standard deviation */
2046 
2047 	if (ntransmitted > 0 && ntransmitted >= nreceived) {
2048 		int missed = ntransmitted - nreceived;
2049 		double loss = 100 * (double)missed / (double)ntransmitted;
2050 
2051 		if (nreceived > 0) {
2052 			rttavg = rttsum / nreceived;
2053 			rttstd = rttssq - (rttavg * rttsum);
2054 			rttstd = xsqrt(rttstd / nreceived);
2055 
2056 			Printf("  %.3f", rttmin);
2057 			Printf("/%.3f", rttavg);
2058 			Printf("/%.3f", rttmax);
2059 
2060 			Printf(" (%.3f) ms ", rttstd);
2061 		}
2062 
2063 		Printf(" %d/%d pkts", nreceived, ntransmitted);
2064 
2065 		if (nreceived == 0)
2066 			Printf(" (100%% loss)");
2067 		else
2068 			Printf(" (%.2g%% loss)", loss);
2069 	}
2070 }
2071 
2072 /*
2073  * square root function
2074  */
2075 double
2076 xsqrt(double y)
2077 {
2078 	double t, x;
2079 
2080 	if (y <= 0) {
2081 		return (0.0);
2082 	}
2083 
2084 	x = (y < 1.0) ? 1.0 : y;
2085 	do {
2086 		t = x;
2087 		x = (t + (y/t))/2.0;
2088 	} while (0 < x && x < t);
2089 
2090 	return (x);
2091 }
2092 
2093 /*
2094  * String to double with optional min and max.
2095  */
2096 static double
2097 str2dbl(const char *str, const char *what, double mi, double ma)
2098 {
2099 	double val;
2100 	char *ep;
2101 
2102 	errno = 0;
2103 
2104 	val = strtod(str, &ep);
2105 	if (errno != 0 || *ep != '\0') {
2106 		Fprintf(stderr, "%s: \"%s\" bad value for %s \n",
2107 		    prog, str, what);
2108 		exit(EXIT_FAILURE);
2109 	}
2110 	if (val < mi && mi >= 0) {
2111 		Fprintf(stderr, "%s: %s must be >= %f\n", prog, what, mi);
2112 		exit(EXIT_FAILURE);
2113 	}
2114 	if (val > ma && ma >= 0) {
2115 		Fprintf(stderr, "%s: %s must be <= %f\n", prog, what, ma);
2116 		exit(EXIT_FAILURE);
2117 	}
2118 	return (val);
2119 }
2120 
2121 /*
2122  * String to int with optional min and max. Handles decimal and hex.
2123  */
2124 static int
2125 str2int(const char *str, const char *what, int mi, int ma)
2126 {
2127 	const char *cp;
2128 	int val;
2129 	char *ep;
2130 
2131 	errno = 0;
2132 
2133 	if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X')) {
2134 		cp = str + 2;
2135 		val = (int)strtol(cp, &ep, 16);
2136 	} else {
2137 		val = (int)strtol(str, &ep, 10);
2138 	}
2139 	if (errno != 0 || *ep != '\0') {
2140 		Fprintf(stderr, "%s: \"%s\" bad value for %s \n",
2141 		    prog, str, what);
2142 		exit(EXIT_FAILURE);
2143 	}
2144 	if (val < mi && mi >= 0) {
2145 		if (mi == 0) {
2146 			Fprintf(stderr, "%s: %s must be >= %d\n",
2147 			    prog, what, mi);
2148 		} else {
2149 			Fprintf(stderr, "%s: %s must be > %d\n",
2150 			    prog, what, mi - 1);
2151 		}
2152 		exit(EXIT_FAILURE);
2153 	}
2154 	if (val > ma && ma >= 0) {
2155 		Fprintf(stderr, "%s: %s must be <= %d\n", prog, what, ma);
2156 		exit(EXIT_FAILURE);
2157 	}
2158 	return (val);
2159 }
2160 
2161 /*
2162  * This is the interrupt handler for SIGINT and SIGQUIT. It's completely handled
2163  * where it jumps to.
2164  */
2165 static void
2166 sig_handler(int sig)
2167 {
2168 	longjmp(env, sig);
2169 }
2170 
2171 /*
2172  * display the usage of traceroute
2173  */
2174 static void
2175 usage(void)
2176 {
2177 	Fprintf(stderr, "Usage: %s [-adFIlnSvx] [-A address_family] "
2178 "[-c traffic_class] \n"
2179 "\t[-f first_hop] [-g gateway [-g gateway ...]| -r] [-i iface]\n"
2180 "\t[-L flow_label] [-m max_hop] [-P pause_sec] [-p port] [-Q max_timeout]\n"
2181 "\t[-q nqueries] [-s src_addr] [-t tos] [-w wait_time] host [packetlen]\n",
2182 		prog);
2183 	exit(EXIT_FAILURE);
2184 }
2185