xref: /openbsd/usr.sbin/mtrace/mtrace.c (revision 09467b48)
1 /*	$OpenBSD: mtrace.c,v 1.40 2019/06/28 13:32:49 deraadt Exp $	*/
2 /*	$NetBSD: mtrace.c,v 1.5 1995/12/10 10:57:15 mycroft Exp $	*/
3 
4 /*
5  * mtrace.c
6  *
7  * This tool traces the branch of a multicast tree from a source to a
8  * receiver for a particular multicast group and gives statistics
9  * about packet rate and loss for each hop along the path.  It can
10  * usually be invoked just as
11  *
12  *	mtrace source
13  *
14  * to trace the route from that source to the local host for a default
15  * group when only the route is desired and not group-specific packet
16  * counts.  See the usage line for more complex forms.
17  *
18  *
19  * Released 4 Apr 1995.  This program was adapted by Steve Casner
20  * (USC/ISI) from a prototype written by Ajit Thyagarajan (UDel and
21  * Xerox PARC).  It attempts to parallel in command syntax and output
22  * format the unicast traceroute program written by Van Jacobson (LBL)
23  * for the parts where that makes sense.
24  *
25  * Copyright (c) 1998-2001.
26  * The University of Southern California/Information Sciences Institute.
27  * All rights reserved.
28  *
29  * Redistribution and use in source and binary forms, with or without
30  * modification, are permitted provided that the following conditions
31  * are met:
32  * 1. Redistributions of source code must retain the above copyright
33  *    notice, this list of conditions and the following disclaimer.
34  * 2. Redistributions in binary form must reproduce the above copyright
35  *    notice, this list of conditions and the following disclaimer in the
36  *    documentation and/or other materials provided with the distribution.
37  * 3. Neither the name of the project nor the names of its contributors
38  *    may be used to endorse or promote products derived from this software
39  *    without specific prior written permission.
40  *
41  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  */
53 
54 #include <netdb.h>
55 #include <sys/time.h>
56 #include <string.h>
57 #include <poll.h>
58 #include <ctype.h>
59 #include <sys/ioctl.h>
60 #include "defs.h"
61 #include <arpa/inet.h>
62 #include <stdarg.h>
63 #ifdef SUNOS5
64 #include <sys/systeminfo.h>
65 #endif
66 #include <ifaddrs.h>
67 #include <err.h>
68 
69 #define DEFAULT_TIMEOUT	3	/* How long to wait before retrying requests */
70 #define DEFAULT_RETRIES 3	/* How many times to try */
71 #define MAXHOPS UNREACHABLE	/* Don't need more hops than max metric */
72 #define UNICAST_TTL 255		/* TTL for unicast response */
73 #define MULTICAST_TTL1 64	/* Default TTL for multicast query/response */
74 #define MULTICAST_TTL_INC 32	/* TTL increment for increase after timeout */
75 #define MULTICAST_TTL_MAX 192	/* Maximum TTL allowed (protect low-BW links */
76 
77 struct resp_buf {
78     u_long qtime;		/* Time query was issued */
79     u_long rtime;		/* Time response was received */
80     int	len;			/* Number of reports or length of data */
81     struct igmp igmp;		/* IGMP header */
82     union {
83 	struct {
84 	    struct tr_query q;		/* Query/response header */
85 	    struct tr_resp r[MAXHOPS];	/* Per-hop reports */
86 	} t;
87 	char d[MAX_DVMRP_DATA_LEN];	/* Neighbor data */
88     } u;
89 } base, incr[2];
90 
91 #define qhdr u.t.q
92 #define resps u.t.r
93 #define ndata u.d
94 
95 char names[MAXHOPS][40];
96 int reset[MAXHOPS];			/* To get around 3.4 bug, ... */
97 int swaps[MAXHOPS];			/* To get around 3.6 bug, ... */
98 
99 int timeout = DEFAULT_TIMEOUT;
100 int nqueries = DEFAULT_RETRIES;
101 int numeric = FALSE;
102 int debug = 0;
103 int passive = FALSE;
104 int multicast = FALSE;
105 int statint = 10;
106 int verbose = 0;
107 
108 u_int32_t defgrp;			/* Default group if not specified */
109 u_int32_t query_cast;			/* All routers multicast addr */
110 u_int32_t resp_cast;			/* Mtrace response multicast addr */
111 
112 u_int32_t lcl_addr = 0;			/* This host address, in NET order */
113 u_int32_t dst_netmask;			/* netmask to go with qdst */
114 
115 /*
116  * Query/response parameters, all initialized to zero and set later
117  * to default values or from options.
118  */
119 u_int32_t qsrc = 0;		/* Source address in the query */
120 u_int32_t qgrp = 0;		/* Group address in the query */
121 u_int32_t qdst = 0;		/* Destination (receiver) address in query */
122 u_char qno  = 0;		/* Max number of hops to query */
123 u_int32_t raddr = 0;		/* Address where response should be sent */
124 int    qttl = 0;		/* TTL for the query packet */
125 u_char rttl = 0;		/* TTL for the response packet */
126 u_int32_t gwy = 0;		/* User-supplied last-hop router address */
127 u_int32_t tdst = 0;		/* Address where trace is sent (last-hop) */
128 
129 vifi_t  numvifs;		/* to keep loader happy */
130 				/* (see kern.c) */
131 
132 char *			inet_name(u_int32_t addr);
133 u_int32_t			host_addr(char *name);
134 /* u_int is promoted u_char */
135 char *			proto_type(u_int type);
136 char *			flag_type(u_int type);
137 
138 u_int32_t			get_netmask(int s, u_int32_t dst);
139 int			get_ttl(struct resp_buf *buf);
140 int			t_diff(u_long a, u_long b);
141 u_long			fixtime(u_long time);
142 int			send_recv(u_int32_t dst, int type, int code,
143 			    int tries, struct resp_buf *save);
144 char *			print_host(u_int32_t addr);
145 char *			print_host2(u_int32_t addr1, u_int32_t addr2);
146 void			print_trace(int index, struct resp_buf *buf);
147 int			what_kind(struct resp_buf *buf, char *why);
148 char *			scale(int *hop);
149 void			stat_line(struct tr_resp *r, struct tr_resp *s,
150 			    int have_next, int *res);
151 void			fixup_stats(struct resp_buf *base,
152 			    struct resp_buf *prev, struct resp_buf *new);
153 int			print_stats(struct resp_buf *base,
154 			    struct resp_buf *prev, struct resp_buf *new);
155 void			check_vif_state(void);
156 u_long			byteswap(u_long v);
157 
158 int			main(int argc, char *argv[]);
159 
160 
161 
162 char   *
163 inet_name(u_int32_t addr)
164 {
165     struct hostent *e;
166 
167     e = gethostbyaddr((char *)&addr, sizeof(addr), AF_INET);
168 
169     return e ? e->h_name : "?";
170 }
171 
172 
173 u_int32_t
174 host_addr(char *name)
175 {
176     struct hostent *e = NULL;
177     u_int32_t  addr;
178     int	i, dots = 3;
179     char	buf[40];
180     char	*ip = name;
181     char	*op = buf;
182 
183     /*
184      * Undo BSD's favor -- take fewer than 4 octets as net/subnet address
185      * if the name is all numeric.
186      */
187     for (i = sizeof(buf) - 7; i > 0; --i) {
188 	if (*ip == '.')
189 		--dots;
190 	else if (*ip == '\0')
191 		break;
192 	else if (!isdigit((unsigned char)*ip))
193 		dots = 0;  /* Not numeric, don't add zeroes */
194 	*op++ = *ip++;
195     }
196     for (i = 0; i < dots; ++i) {
197 	*op++ = '.';
198 	*op++ = '0';
199     }
200     *op = '\0';
201 
202     if (dots <= 0) e = gethostbyname(name);
203     if (e) memcpy((char *)&addr, e->h_addr_list[0], e->h_length);
204     else {
205 	addr = inet_addr(buf);
206 	if (addr == -1) {
207 	    addr = 0;
208 	    printf("Could not parse %s as host name or address\n", name);
209 	}
210     }
211     return addr;
212 }
213 
214 
215 char *
216 proto_type(u_int type)
217 {
218     static char buf[80];
219 
220     switch (type) {
221       case PROTO_DVMRP:
222 	return ("DVMRP");
223       case PROTO_MOSPF:
224 	return ("MOSPF");
225       case PROTO_PIM:
226 	return ("PIM");
227       case PROTO_CBT:
228 	return ("CBT");
229       default:
230 	(void) snprintf(buf, sizeof buf, "Unknown protocol code %d", type);
231 	return (buf);
232     }
233 }
234 
235 
236 char *
237 flag_type(u_int type)
238 {
239     static char buf[80];
240 
241     switch (type) {
242       case TR_NO_ERR:
243 	return ("");
244       case TR_WRONG_IF:
245 	return ("Wrong interface");
246       case TR_PRUNED:
247 	return ("Prune sent upstream");
248       case TR_OPRUNED:
249 	return ("Output pruned");
250       case TR_SCOPED:
251 	return ("Hit scope boundary");
252       case TR_NO_RTE:
253 	return ("No route");
254       case TR_OLD_ROUTER:
255 	return ("Next router no mtrace");
256       case TR_NO_FWD:
257 	return ("Not forwarding");
258       case TR_NO_SPACE:
259 	return ("No space in packet");
260       default:
261 	(void) snprintf(buf, sizeof buf, "Unknown error code %d", type);
262 	return (buf);
263     }
264 }
265 
266 /*
267  * If destination is on a local net, get the netmask, else set the
268  * netmask to all ones.  There are two side effects: if the local
269  * address was not explicitly set, and if the destination is on a
270  * local net, use that one; in either case, verify that the local
271  * address is valid.
272  */
273 
274 u_int32_t
275 get_netmask(int s, u_int32_t dst)
276 {
277     u_int32_t if_addr, if_mask;
278     u_int32_t retval = 0xFFFFFFFF;
279     int found = FALSE;
280     struct ifaddrs *ifap, *ifa;
281 
282     if (getifaddrs(&ifap) != 0) {
283 	perror("getifaddrs");
284 	return (retval);
285     }
286     for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
287 	if (ifa->ifa_addr->sa_family != AF_INET)
288              continue;
289 	if_addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr;
290 	if_mask = ((struct sockaddr_in *)ifa->ifa_netmask)->sin_addr.s_addr;
291 	if ((dst & if_mask) == (if_addr & if_mask)) {
292 	    retval = if_mask;
293 	    if (lcl_addr == 0)
294 		lcl_addr = if_addr;
295 	}
296 	if (lcl_addr == if_addr)
297 	    found = TRUE;
298     }
299     if (!found && lcl_addr != 0) {
300 	printf("Interface address is not valid\n");
301 	exit(1);
302     }
303     freeifaddrs(ifap);
304     return (retval);
305 }
306 
307 
308 int
309 get_ttl(struct resp_buf *buf)
310 {
311     int rno;
312     struct tr_resp *b;
313     u_int ttl;
314 
315     if (buf && (rno = buf->len) > 0) {
316 	b = buf->resps + rno - 1;
317 	ttl = b->tr_fttl;
318 
319 	while (--rno > 0) {
320 	    --b;
321 	    if (ttl < b->tr_fttl) ttl = b->tr_fttl;
322 	    else ++ttl;
323 	}
324 	ttl += MULTICAST_TTL_INC;
325 	if (ttl < MULTICAST_TTL1) ttl = MULTICAST_TTL1;
326 	if (ttl > MULTICAST_TTL_MAX) ttl = MULTICAST_TTL_MAX;
327 	return (ttl);
328     } else return(MULTICAST_TTL1);
329 }
330 
331 /*
332  * Calculate the difference between two 32-bit NTP timestamps and return
333  * the result in milliseconds.
334  */
335 int
336 t_diff(u_long a, u_long b)
337 {
338     int d = a - b;
339 
340     return ((d * 125) >> 13);
341 }
342 
343 /*
344  * Fixup for incorrect time format in 3.3 mrouted.
345  * This is possible because (JAN_1970 mod 64K) is quite close to 32K,
346  * so correct and incorrect times will be far apart.
347  */
348 u_long
349 fixtime(u_long time)
350 {
351     if (abs((int)(time-base.qtime)) > 0x3FFFFFFF)
352         time = ((time & 0xFFFF0000) + (JAN_1970 << 16)) +
353 	       ((time & 0xFFFF) << 14) / 15625;
354     return (time);
355 }
356 
357 /*
358  * Swap bytes for poor little-endian machines that don't byte-swap
359  */
360 u_long
361 byteswap(u_long v)
362 {
363     return ((v << 24) | ((v & 0xff00) << 8) |
364 	    ((v >> 8) & 0xff00) | (v >> 24));
365 }
366 
367 int
368 send_recv(u_int32_t dst, int type, int code, int tries, struct resp_buf *save)
369 {
370     struct timeval tq, tr, tv;
371     struct ip *ip;
372     struct igmp *igmp;
373     struct tr_query *query, *rquery;
374     int ipdatalen, iphdrlen, igmpdatalen;
375     u_int32_t local, group;
376     int datalen;
377     struct pollfd pfd[1];
378     int count, recvlen, dummy = 0;
379     int len;
380     int i;
381 
382     if (type == IGMP_MTRACE_QUERY) {
383 	group = qgrp;
384 	datalen = sizeof(struct tr_query);
385     } else {
386 	group = htonl(MROUTED_LEVEL);
387 	datalen = 0;
388     }
389     if (IN_MULTICAST(ntohl(dst))) local = lcl_addr;
390     else local = INADDR_ANY;
391 
392     /*
393      * If the reply address was not explicitly specified, start off
394      * with the unicast address of this host.  Then, if there is no
395      * response after trying half the tries with unicast, switch to
396      * the standard multicast reply address.  If the TTL was also not
397      * specified, set a multicast TTL and if needed increase it for the
398      * last quarter of the tries.
399      */
400     query = (struct tr_query *)(send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN);
401     query->tr_raddr = raddr ? raddr : multicast ? resp_cast : lcl_addr;
402     query->tr_rttl  = rttl ? rttl :
403       IN_MULTICAST(ntohl(query->tr_raddr)) ? get_ttl(save) : UNICAST_TTL;
404     query->tr_src   = qsrc;
405     query->tr_dst   = qdst;
406 
407     for (i = tries ; i > 0; --i) {
408 	if (tries == nqueries && raddr == 0) {
409 	    if (i == ((nqueries + 1) >> 1)) {
410 		query->tr_raddr = resp_cast;
411 		if (rttl == 0) query->tr_rttl = get_ttl(save);
412 	    }
413 	    if (i <= ((nqueries + 3) >> 2) && rttl == 0) {
414 		query->tr_rttl += MULTICAST_TTL_INC;
415 		if (query->tr_rttl > MULTICAST_TTL_MAX)
416 		  query->tr_rttl = MULTICAST_TTL_MAX;
417 	    }
418 	}
419 
420 	/*
421 	 * Change the qid for each request sent to avoid being confused
422 	 * by duplicate responses
423 	 */
424 	query->tr_qid  = arc4random();
425 
426 	/*
427 	 * Set timer to calculate delays, then send query
428 	 */
429 	gettimeofday(&tq, 0);
430 	send_igmp(local, dst, type, code, group, datalen);
431 
432 	/*
433 	 * Wait for response, discarding false alarms
434 	 */
435 	pfd[0].fd = igmp_socket;
436 	pfd[0].events = POLLIN;
437 	while (TRUE) {
438 	    gettimeofday(&tv, 0);
439 	    tv.tv_sec = tq.tv_sec + timeout - tv.tv_sec;
440 	    tv.tv_usec = tq.tv_usec - tv.tv_usec;
441 	    if (tv.tv_usec < 0) tv.tv_usec += 1000000L, --tv.tv_sec;
442 	    if (tv.tv_sec < 0) tv.tv_sec = tv.tv_usec = 0;
443 
444 	    count = poll(pfd, 1, tv.tv_sec * 1000);
445 
446 	    if (count == -1) {
447 		if (errno != EINTR) perror("poll");
448 		continue;
449 	    } else if (count == 0) {
450 		printf("* ");
451 		fflush(stdout);
452 		break;
453 	    }
454 
455 	    gettimeofday(&tr, 0);
456 	    recvlen = recvfrom(igmp_socket, recv_buf, RECV_BUF_SIZE,
457 			       0, NULL, &dummy);
458 
459 	    if (recvlen <= 0) {
460 		if (recvlen && errno != EINTR) perror("recvfrom");
461 		continue;
462 	    }
463 
464 	    if (recvlen < sizeof(struct ip)) {
465 		fprintf(stderr,
466 			"packet too short (%u bytes) for IP header", recvlen);
467 		continue;
468 	    }
469 	    ip = (struct ip *) recv_buf;
470 	    if (ip->ip_p == 0)	/* ignore cache creation requests */
471 		continue;
472 
473 	    iphdrlen = ip->ip_hl << 2;
474 	    ipdatalen = ntohs(ip->ip_len) - iphdrlen;
475 	    if (iphdrlen + ipdatalen != recvlen) {
476 		fprintf(stderr,
477 			"packet shorter (%u bytes) than hdr+data len (%u+%u)\n",
478 			recvlen, iphdrlen, ipdatalen);
479 		continue;
480 	    }
481 
482 	    igmp = (struct igmp *) (recv_buf + iphdrlen);
483 	    igmpdatalen = ipdatalen - IGMP_MINLEN;
484 	    if (igmpdatalen < 0) {
485 		fprintf(stderr,
486 			"IP data field too short (%u bytes) for IGMP from %s\n",
487 			ipdatalen, inet_fmt(ip->ip_src.s_addr, s1));
488 		continue;
489 	    }
490 
491 	    switch (igmp->igmp_type) {
492 
493 	      case IGMP_DVMRP:
494 		if (igmp->igmp_code != DVMRP_NEIGHBORS2) continue;
495 		len = igmpdatalen;
496 		/*
497 		 * Accept DVMRP_NEIGHBORS2 response if it comes from the
498 		 * address queried or if that address is one of the local
499 		 * addresses in the response.
500 		 */
501 		if (ip->ip_src.s_addr != dst) {
502 		    u_int32_t *p = (u_int32_t *)(igmp + 1);
503 		    u_int32_t *ep = p + (len >> 2);
504 		    while (p < ep) {
505 			u_int32_t laddr = *p++;
506 			int n = ntohl(*p++) & 0xFF;
507 			if (laddr == dst) {
508 			    ep = p + 1;		/* ensure p < ep after loop */
509 			    break;
510 			}
511 			p += n;
512 		    }
513 		    if (p >= ep) continue;
514 		}
515 		break;
516 
517 	      case IGMP_MTRACE_QUERY:	    /* For backward compatibility with 3.3 */
518 	      case IGMP_MTRACE_REPLY:
519 		if (igmpdatalen <= QLEN) continue;
520 		if ((igmpdatalen - QLEN)%RLEN) {
521 		    printf("packet with incorrect datalen\n");
522 		    continue;
523 		}
524 
525 		/*
526 		 * Ignore responses that don't match query.
527 		 */
528 		rquery = (struct tr_query *)(igmp + 1);
529 		if (rquery->tr_qid != query->tr_qid) continue;
530 		if (rquery->tr_src != qsrc) continue;
531 		if (rquery->tr_dst != qdst) continue;
532 		len = (igmpdatalen - QLEN)/RLEN;
533 
534 		/*
535 		 * Ignore trace queries passing through this node when
536 		 * mtrace is run on an mrouter that is in the path
537 		 * (needed only because IGMP_MTRACE_QUERY is accepted above
538 		 * for backward compatibility with multicast release 3.3).
539 		 */
540 		if (igmp->igmp_type == IGMP_MTRACE_QUERY) {
541 		    struct tr_resp *r = (struct tr_resp *)(rquery+1) + len - 1;
542 		    u_int32_t smask;
543 
544 		    VAL_TO_MASK(smask, r->tr_smask);
545 		    if (len < code && (r->tr_inaddr & smask) != (qsrc & smask)
546 			&& r->tr_rmtaddr != 0 && !(r->tr_rflags & 0x80))
547 		      continue;
548 		}
549 
550 		/*
551 		 * A match, we'll keep this one.
552 		 */
553 		if (len > code) {
554 		    fprintf(stderr,
555 			    "Num hops received (%d) exceeds request (%d)\n",
556 			    len, code);
557 		}
558 		rquery->tr_raddr = query->tr_raddr;	/* Insure these are */
559 		rquery->tr_rttl = query->tr_rttl;	/* as we sent them */
560 		break;
561 
562 	      default:
563 		continue;
564 	    }
565 
566 	    /*
567 	     * Most of the sanity checking done at this point.
568 	     * Return this packet we have been waiting for.
569 	     */
570 	    if (save) {
571 		save->qtime = ((tq.tv_sec + JAN_1970) << 16) +
572 			      (tq.tv_usec << 10) / 15625;
573 		save->rtime = ((tr.tv_sec + JAN_1970) << 16) +
574 			      (tr.tv_usec << 10) / 15625;
575 		save->len = len;
576 		bcopy((char *)igmp, (char *)&save->igmp, ipdatalen);
577 	    }
578 	    return (recvlen);
579 	}
580     }
581     return (0);
582 }
583 
584 /*
585  * Most of this code is duplicated elsewhere.  I'm not sure if
586  * the duplication is absolutely required or not.
587  *
588  * Ideally, this would keep track of ongoing statistics
589  * collection and print out statistics.  (& keep track
590  * of h-b-h traces and only print the longest)  For now,
591  * it just snoops on what traces it can.
592  */
593 void
594 passive_mode(void)
595 {
596     struct timeval tr;
597     struct ip *ip;
598     struct igmp *igmp;
599     struct tr_resp *r;
600     int ipdatalen, iphdrlen, igmpdatalen;
601     int len, recvlen, dummy = 0;
602     u_int32_t smask;
603 
604     if (raddr) {
605 	if (IN_MULTICAST(ntohl(raddr))) k_join(raddr, INADDR_ANY);
606     } else k_join(htonl(0xE0000120), INADDR_ANY);
607 
608     while (1) {
609 	recvlen = recvfrom(igmp_socket, recv_buf, RECV_BUF_SIZE,
610 			   0, NULL, &dummy);
611 	gettimeofday(&tr,0);
612 
613 	if (recvlen <= 0) {
614 	    if (recvlen && errno != EINTR) perror("recvfrom");
615 	    continue;
616 	}
617 
618 	if (recvlen < sizeof(struct ip)) {
619 	    fprintf(stderr,
620 		    "packet too short (%u bytes) for IP header", recvlen);
621 	    continue;
622 	}
623 	ip = (struct ip *) recv_buf;
624 	if (ip->ip_p == 0)	/* ignore cache creation requests */
625 	    continue;
626 
627 	iphdrlen = ip->ip_hl << 2;
628 	ipdatalen = ntohs(ip->ip_len) - iphdrlen;
629 	if (iphdrlen + ipdatalen != recvlen) {
630 	    fprintf(stderr,
631 		    "packet shorter (%u bytes) than hdr+data len (%u+%u)\n",
632 		    recvlen, iphdrlen, ipdatalen);
633 	    continue;
634 	}
635 
636 	igmp = (struct igmp *) (recv_buf + iphdrlen);
637 	igmpdatalen = ipdatalen - IGMP_MINLEN;
638 	if (igmpdatalen < 0) {
639 	    fprintf(stderr,
640 		    "IP data field too short (%u bytes) for IGMP from %s\n",
641 		    ipdatalen, inet_fmt(ip->ip_src.s_addr, s1));
642 	    continue;
643 	}
644 
645 	switch (igmp->igmp_type) {
646 
647 	  case IGMP_MTRACE_QUERY:	    /* For backward compatibility with 3.3 */
648 	  case IGMP_MTRACE_REPLY:
649 	    if (igmpdatalen < QLEN) continue;
650 	    if ((igmpdatalen - QLEN)%RLEN) {
651 		printf("packet with incorrect datalen\n");
652 		continue;
653 	    }
654 
655 	    len = (igmpdatalen - QLEN)/RLEN;
656 
657 	    break;
658 
659 	  default:
660 	    continue;
661 	}
662 
663 	base.qtime = ((tr.tv_sec + JAN_1970) << 16) +
664 		      (tr.tv_usec << 10) / 15625;
665 	base.rtime = ((tr.tv_sec + JAN_1970) << 16) +
666 		      (tr.tv_usec << 10) / 15625;
667 	base.len = len;
668 	bcopy((char *)igmp, (char *)&base.igmp, ipdatalen);
669 	/*
670 	 * If the user specified which traces to monitor,
671 	 * only accept traces that correspond to the
672 	 * request
673 	 */
674 	if ((qsrc != 0 && qsrc != base.qhdr.tr_src) ||
675 	    (qdst != 0 && qdst != base.qhdr.tr_dst) ||
676 	    (qgrp != 0 && qgrp != igmp->igmp_group.s_addr))
677 	    continue;
678 
679 	printf("Mtrace from %s to %s via group %s (mxhop=%d)\n",
680 		inet_fmt(base.qhdr.tr_dst, s1), inet_fmt(base.qhdr.tr_src, s2),
681 		inet_fmt(igmp->igmp_group.s_addr, s3), igmp->igmp_code);
682 	if (len == 0)
683 	    continue;
684 	printf("  0  ");
685 	print_host(base.qhdr.tr_dst);
686 	printf("\n");
687 	print_trace(1, &base);
688 	r = base.resps + base.len - 1;
689 	VAL_TO_MASK(smask, r->tr_smask);
690 	if ((r->tr_inaddr & smask) == (base.qhdr.tr_src & smask)) {
691 	    printf("%3d  ", -(base.len+1));
692 	    print_host(base.qhdr.tr_src);
693 	    printf("\n");
694 	} else if (r->tr_rmtaddr != 0) {
695 	    printf("%3d  ", -(base.len+1));
696 	    what_kind(&base, r->tr_rflags == TR_OLD_ROUTER ?
697 				   "doesn't support mtrace"
698 				 : "is the next hop");
699 	}
700 	printf("\n");
701     }
702 }
703 
704 char *
705 print_host(u_int32_t addr)
706 {
707     return print_host2(addr, 0);
708 }
709 
710 /*
711  * On some routers, one interface has a name and the other doesn't.
712  * We always print the address of the outgoing interface, but can
713  * sometimes get the name from the incoming interface.  This might be
714  * confusing but should be slightly more helpful than just a "?".
715  */
716 char *
717 print_host2(u_int32_t addr1, u_int32_t addr2)
718 {
719     char *name;
720 
721     if (numeric) {
722 	printf("%s", inet_fmt(addr1, s1));
723 	return ("");
724     }
725     name = inet_name(addr1);
726     if (*name == '?' && *(name + 1) == '\0' && addr2 != 0)
727 	name = inet_name(addr2);
728     printf("%s (%s)", name, inet_fmt(addr1, s1));
729     return (name);
730 }
731 
732 /*
733  * Print responses as received (reverse path from dst to src)
734  */
735 void
736 print_trace(int index, struct resp_buf *buf)
737 {
738     struct tr_resp *r;
739     char *name;
740     int i;
741     int hop;
742     char *ms;
743 
744     i = abs(index);
745     r = buf->resps + i - 1;
746 
747     for (; i <= buf->len; ++i, ++r) {
748 	if (index > 0) printf("%3d  ", -i);
749 	name = print_host2(r->tr_outaddr, r->tr_inaddr);
750 	printf("  %s  thresh^ %d", proto_type(r->tr_rproto), r->tr_fttl);
751 	if (verbose) {
752 	    hop = t_diff(fixtime(ntohl(r->tr_qarr)), buf->qtime);
753 	    ms = scale(&hop);
754 	    printf("  %d%s", hop, ms);
755 	}
756 	printf("  %s\n", flag_type(r->tr_rflags));
757 	memcpy(names[i-1], name, sizeof(names[0]) - 1);
758 	names[i-1][sizeof(names[0])-1] = '\0';
759     }
760 }
761 
762 /*
763  * See what kind of router is the next hop
764  */
765 int
766 what_kind(struct resp_buf *buf, char *why)
767 {
768     u_int32_t smask;
769     int retval;
770     int hops = buf->len;
771     struct tr_resp *r = buf->resps + hops - 1;
772     u_int32_t next = r->tr_rmtaddr;
773 
774     retval = send_recv(next, IGMP_DVMRP, DVMRP_ASK_NEIGHBORS2, 1, &incr[0]);
775     print_host(next);
776     if (retval) {
777 	u_int32_t version = ntohl(incr[0].igmp.igmp_group.s_addr);
778 	u_int32_t *p = (u_int32_t *)incr[0].ndata;
779 	u_int32_t *ep = p + (incr[0].len >> 2);
780 	char *type = "";
781 	retval = 0;
782 	switch (version & 0xFF) {
783 	  case 1:
784 	    type = "proteon/mrouted ";
785 	    retval = 1;
786 	    break;
787 
788 	  case 2:
789 	  case 3:
790 	    if (((version >> 8) & 0xFF) < 3) retval = 1;
791 				/* Fall through */
792 	  case 4:
793 	    type = "mrouted ";
794 	    break;
795 
796 	  case 10:
797 	    type = "cisco ";
798 	}
799 	printf(" [%s%d.%d] %s\n",
800 	       type, version & 0xFF, (version >> 8) & 0xFF,
801 	       why);
802 	VAL_TO_MASK(smask, r->tr_smask);
803 	while (p < ep) {
804 	    u_int32_t laddr = *p++;
805 	    int flags = (ntohl(*p) & 0xFF00) >> 8;
806 	    int n = ntohl(*p++) & 0xFF;
807 	    if (!(flags & (DVMRP_NF_DOWN | DVMRP_NF_DISABLED)) &&
808 		 (laddr & smask) == (qsrc & smask)) {
809 		printf("%3d  ", -(hops+2));
810 		print_host(qsrc);
811 		printf("\n");
812 		return 1;
813 	    }
814 	    p += n;
815 	}
816 	return retval;
817     }
818     printf(" %s\n", why);
819     return 0;
820 }
821 
822 
823 char *
824 scale(int *hop)
825 {
826     if (*hop > -1000 && *hop < 10000) return (" ms");
827     *hop /= 1000;
828     if (*hop > -1000 && *hop < 10000) return (" s ");
829     return ("s ");
830 }
831 
832 /*
833  * Calculate and print one line of packet loss and packet rate statistics.
834  * Checks for count of all ones from mrouted 2.3 that doesn't have counters.
835  */
836 #define NEITHER 0
837 #define INS     1
838 #define OUTS    2
839 #define BOTH    3
840 void
841 stat_line(struct tr_resp *r, struct tr_resp *s, int have_next, int *rst)
842 {
843     int timediff = (fixtime(ntohl(s->tr_qarr)) -
844 			 fixtime(ntohl(r->tr_qarr))) >> 16;
845     int v_lost, v_pct;
846     int g_lost, g_pct;
847     int v_out = ntohl(s->tr_vifout) - ntohl(r->tr_vifout);
848     int g_out = ntohl(s->tr_pktcnt) - ntohl(r->tr_pktcnt);
849     int v_pps, g_pps;
850     char v_str[8], g_str[8];
851     int have = NEITHER;
852     int res = *rst;
853 
854     if (timediff == 0) timediff = 1;
855     v_pps = v_out / timediff;
856     g_pps = g_out / timediff;
857 
858     if ((v_out && (s->tr_vifout != 0xFFFFFFFF && s->tr_vifout != 0)) ||
859 		 (r->tr_vifout != 0xFFFFFFFF && r->tr_vifout != 0))
860 	    have |= OUTS;
861 
862     if (have_next) {
863 	--r,  --s,  --rst;
864 	if ((s->tr_vifin != 0xFFFFFFFF && s->tr_vifin != 0) ||
865 	    (r->tr_vifin != 0xFFFFFFFF && r->tr_vifin != 0))
866 	  have |= INS;
867 	if (*rst)
868 	  res = 1;
869     }
870 
871     switch (have) {
872       case BOTH:
873 	v_lost = v_out - (ntohl(s->tr_vifin) - ntohl(r->tr_vifin));
874 	if (v_out) v_pct = (v_lost * 100 + (v_out >> 1)) / v_out;
875 	else v_pct = 0;
876 	if (-100 < v_pct && v_pct < 101 && v_out > 10)
877 	  snprintf(v_str, sizeof v_str, "%3d", v_pct);
878 	else memcpy(v_str, " --", 4);
879 
880 	g_lost = g_out - (ntohl(s->tr_pktcnt) - ntohl(r->tr_pktcnt));
881 	if (g_out) g_pct = (g_lost * 100 + (g_out >> 1))/ g_out;
882 	else g_pct = 0;
883 	if (-100 < g_pct && g_pct < 101 && g_out > 10)
884 	  snprintf(g_str, sizeof g_str, "%3d", g_pct);
885 	else memcpy(g_str, " --", 4);
886 
887 	printf("%6d/%-5d=%s%%%4d pps",
888 	       v_lost, v_out, v_str, v_pps);
889 	if (res)
890 	    printf("\n");
891 	else
892 	    printf("%6d/%-5d=%s%%%4d pps\n",
893 		   g_lost, g_out, g_str, g_pps);
894 	break;
895 
896       case INS:
897 	v_out = ntohl(s->tr_vifin) - ntohl(r->tr_vifin);
898 	v_pps = v_out / timediff;
899 	/* Fall through */
900 
901       case OUTS:
902 	printf("       %-5d     %4d pps",
903 	       v_out, v_pps);
904 	if (res)
905 	    printf("\n");
906 	else
907 	    printf("       %-5d     %4d pps\n",
908 		   g_out, g_pps);
909 	break;
910 
911       case NEITHER:
912 	printf("\n");
913 	break;
914     }
915 
916     if (debug > 2) {
917 	printf("\t\t\t\tv_in: %u ", ntohl(s->tr_vifin));
918 	printf("v_out: %u ", ntohl(s->tr_vifout));
919 	printf("pkts: %u\n", ntohl(s->tr_pktcnt));
920 	printf("\t\t\t\tv_in: %u ", ntohl(r->tr_vifin));
921 	printf("v_out: %u ", ntohl(r->tr_vifout));
922 	printf("pkts: %u\n", ntohl(r->tr_pktcnt));
923 	printf("\t\t\t\tv_in: %u ", ntohl(s->tr_vifin)-ntohl(r->tr_vifin));
924 	printf("v_out: %u ", ntohl(s->tr_vifout) - ntohl(r->tr_vifout));
925 	printf("pkts: %u ", ntohl(s->tr_pktcnt) - ntohl(r->tr_pktcnt));
926 	printf("time: %d\n", timediff);
927 	printf("\t\t\t\tres: %d\n", res);
928     }
929 }
930 
931 /*
932  * A fixup to check if any pktcnt has been reset, and to fix the
933  * byteorder bugs in mrouted 3.6 on little-endian machines.
934  */
935 void
936 fixup_stats(struct resp_buf *base, struct resp_buf *prev, struct resp_buf *new)
937 {
938     int rno = base->len;
939     struct tr_resp *b = base->resps + rno;
940     struct tr_resp *p = prev->resps + rno;
941     struct tr_resp *n = new->resps + rno;
942     int *r = reset + rno;
943     int *s = swaps + rno;
944     int res;
945 
946     /* Check for byte-swappers */
947     while (--rno >= 0) {
948 	--n; --p; --b; --s;
949 	if (*s || ntohl(n->tr_vifout) - ntohl(p->tr_vifout) > 100000) {
950 	    /* This host sends byteswapped reports; swap 'em */
951 	    if (!*s) {
952 		*s = 1;
953 		b->tr_qarr = byteswap(b->tr_qarr);
954 		b->tr_vifin = byteswap(b->tr_vifin);
955 		b->tr_vifout = byteswap(b->tr_vifout);
956 		b->tr_pktcnt = byteswap(b->tr_pktcnt);
957 	    }
958 
959 	    n->tr_qarr = byteswap(n->tr_qarr);
960 	    n->tr_vifin = byteswap(n->tr_vifin);
961 	    n->tr_vifout = byteswap(n->tr_vifout);
962 	    n->tr_pktcnt = byteswap(n->tr_pktcnt);
963 	}
964     }
965 
966     rno = base->len;
967     b = base->resps + rno;
968     p = prev->resps + rno;
969     n = new->resps + rno;
970 
971     while (--rno >= 0) {
972 	--n; --p; --b; --r;
973 	res = ((ntohl(n->tr_pktcnt) < ntohl(b->tr_pktcnt)) ||
974 	       (ntohl(n->tr_pktcnt) < ntohl(p->tr_pktcnt)));
975 	if (debug > 2)
976 	    printf("\t\tr=%d, res=%d\n", *r, res);
977 	if (*r) {
978 	    if (res || *r > 1) {
979 		/*
980 		 * This router appears to be a 3.4 with that nasty ol'
981 		 * neighbor version bug, which causes it to constantly
982 		 * reset.  Just nuke the statistics for this node, and
983 		 * don't even bother giving it the benefit of the
984 		 * doubt from now on.
985 		 */
986 		p->tr_pktcnt = b->tr_pktcnt = n->tr_pktcnt;
987 		r++;
988 	    } else {
989 		/*
990 		 * This is simply the situation that the original
991 		 * fixup_stats was meant to deal with -- that a
992 		 * 3.3 or 3.4 router deleted a cache entry while
993 		 * traffic was still active.
994 		 */
995 		*r = 0;
996 		break;
997 	    }
998 	} else
999 	    *r = res;
1000     }
1001 
1002     if (rno < 0) return;
1003 
1004     rno = base->len;
1005     b = base->resps + rno;
1006     p = prev->resps + rno;
1007 
1008     while (--rno >= 0) (--b)->tr_pktcnt = (--p)->tr_pktcnt;
1009 }
1010 
1011 /*
1012  * Print responses with statistics for forward path (from src to dst)
1013  */
1014 int
1015 print_stats(struct resp_buf *base, struct resp_buf *prev, struct resp_buf *new)
1016 {
1017     int rtt, hop;
1018     char *ms;
1019     u_int32_t smask;
1020     int rno = base->len - 1;
1021     struct tr_resp *b = base->resps + rno;
1022     struct tr_resp *p = prev->resps + rno;
1023     struct tr_resp *n = new->resps + rno;
1024     int *r = reset + rno;
1025     u_long resptime = new->rtime;
1026     u_long qarrtime = fixtime(ntohl(n->tr_qarr));
1027     u_int ttl = n->tr_fttl;
1028     int first = (base == prev);
1029 
1030     VAL_TO_MASK(smask, b->tr_smask);
1031     printf("  Source        Response Dest");
1032     printf("    Packet Statistics For     Only For Traffic\n");
1033     printf("%-15s %-15s  All Multicast Traffic     From %s\n",
1034 	   ((b->tr_inaddr & smask) == (qsrc & smask)) ? s1 : "   * * *       ",
1035 	   inet_fmt(base->qhdr.tr_raddr, s2), inet_fmt(qsrc, s1));
1036     rtt = t_diff(resptime, new->qtime);
1037     ms = scale(&rtt);
1038     printf("     %c       __/  rtt%5d%s    Lost/Sent = Pct  Rate       To %s\n",
1039 	   first ? 'v' : '|', rtt, ms, inet_fmt(qgrp, s2));
1040     if (!first) {
1041 	hop = t_diff(resptime, qarrtime);
1042 	ms = scale(&hop);
1043 	printf("     v      /     hop%5d%s", hop, ms);
1044 	printf("    ---------------------     --------------------\n");
1045     }
1046     if (debug > 2) {
1047 	printf("\t\t\t\tv_in: %u ", ntohl(n->tr_vifin));
1048 	printf("v_out: %u ", ntohl(n->tr_vifout));
1049 	printf("pkts: %u\n", ntohl(n->tr_pktcnt));
1050 	printf("\t\t\t\tv_in: %u ", ntohl(b->tr_vifin));
1051 	printf("v_out: %u ", ntohl(b->tr_vifout));
1052 	printf("pkts: %u\n", ntohl(b->tr_pktcnt));
1053 	printf("\t\t\t\tv_in: %u ", ntohl(n->tr_vifin) - ntohl(b->tr_vifin));
1054 	printf("v_out: %u ", ntohl(n->tr_vifout) - ntohl(b->tr_vifout));
1055 	printf("pkts: %u\n", ntohl(n->tr_pktcnt) - ntohl(b->tr_pktcnt));
1056 	printf("\t\t\t\treset: %d\n", *r);
1057     }
1058 
1059     while (TRUE) {
1060 	if ((n->tr_inaddr != b->tr_inaddr) || (p->tr_inaddr != b->tr_inaddr))
1061 	  return 1;		/* Route changed */
1062 
1063 	if ((n->tr_inaddr != n->tr_outaddr))
1064 	  printf("%-15s\n", inet_fmt(n->tr_inaddr, s1));
1065 	printf("%-15s %-14s %s\n", inet_fmt(n->tr_outaddr, s1), names[rno],
1066 		 flag_type(n->tr_rflags));
1067 
1068 	if (rno-- < 1) break;
1069 
1070 	printf("     %c     ^      ttl%5d   ", first ? 'v' : '|', ttl);
1071 	stat_line(p, n, TRUE, r);
1072 	if (!first) {
1073 	    resptime = qarrtime;
1074 	    qarrtime = fixtime(ntohl((n-1)->tr_qarr));
1075 	    hop = t_diff(resptime, qarrtime);
1076 	    ms = scale(&hop);
1077 	    printf("     v     |      hop%5d%s", hop, ms);
1078 	    stat_line(b, n, TRUE, r);
1079 	}
1080 
1081 	--b, --p, --n, --r;
1082 	if (ttl < n->tr_fttl) ttl = n->tr_fttl;
1083 	else ++ttl;
1084     }
1085 
1086     printf("     %c      \\__   ttl%5d   ", first ? 'v' : '|', ttl);
1087     stat_line(p, n, FALSE, r);
1088     if (!first) {
1089 	hop = t_diff(qarrtime, new->qtime);
1090 	ms = scale(&hop);
1091 	printf("     v         \\  hop%5d%s", hop, ms);
1092 	stat_line(b, n, FALSE, r);
1093     }
1094     printf("%-15s %s\n", inet_fmt(qdst, s1), inet_fmt(lcl_addr, s2));
1095     printf("  Receiver      Query Source\n\n");
1096     return 0;
1097 }
1098 
1099 
1100 /***************************************************************************
1101  *	main
1102  ***************************************************************************/
1103 
1104 int
1105 main(int argc, char *argv[])
1106 {
1107     int udp;
1108     struct sockaddr_in addr;
1109     int addrlen = sizeof(addr);
1110     int recvlen;
1111     struct timeval tv;
1112     struct resp_buf *prev, *new;
1113     struct tr_resp *r;
1114     u_int32_t smask;
1115     int rno;
1116     int hops, nexthop, tries;
1117     u_int32_t lastout = 0;
1118     int numstats = 1;
1119     int waittime;
1120     uid_t uid;
1121 
1122     init_igmp();
1123 
1124     uid = getuid();
1125     if (setresuid(uid, uid, uid) == -1)
1126 	err(1, "setresuid");
1127 
1128     argv++, argc--;
1129     if (argc == 0) goto usage;
1130 
1131     while (argc > 0 && *argv[0] == '-') {
1132 	char *p = *argv++;  argc--;
1133 	p++;
1134 	do {
1135 	    char c = *p++;
1136 	    char *arg = NULL;
1137 	    if (isdigit((unsigned char)*p)) {
1138 		arg = p;
1139 		p = "";
1140 	    } else if (argc > 0) arg = argv[0];
1141 	    switch (c) {
1142 	      case 'd':			/* Unlisted debug print option */
1143 		if (arg && isdigit((unsigned char)*arg)) {
1144 		    debug = atoi(arg);
1145 		    if (debug < 0) debug = 0;
1146 		    if (debug > 3) debug = 3;
1147 		    if (arg == argv[0]) argv++, argc--;
1148 		    break;
1149 		} else
1150 		    goto usage;
1151 	      case 'M':			/* Use multicast for response */
1152 		multicast = TRUE;
1153 		break;
1154 	      case 'l':			/* Loop updating stats indefinitely */
1155 		numstats = 3153600;
1156 		break;
1157 	      case 'n':			/* Don't reverse map host addresses */
1158 		numeric = TRUE;
1159 		break;
1160 	      case 'p':			/* Passive listen for traces */
1161 		passive = TRUE;
1162 		break;
1163 	      case 'v':			/* Verbosity */
1164 		verbose = TRUE;
1165 		break;
1166 	      case 's':			/* Short form, don't wait for stats */
1167 		numstats = 0;
1168 		break;
1169 	      case 'w':			/* Time to wait for packet arrival */
1170 		if (arg && isdigit((unsigned char)*arg)) {
1171 		    timeout = atoi(arg);
1172 		    if (timeout < 1) timeout = 1;
1173 		    if (arg == argv[0]) argv++, argc--;
1174 		    break;
1175 		} else
1176 		    goto usage;
1177 	      case 'm':			/* Max number of hops to trace */
1178 		if (arg && isdigit((unsigned char)*arg)) {
1179 		    qno = atoi(arg);
1180 		    if (qno > MAXHOPS) qno = MAXHOPS;
1181 		    else if (qno < 1) qno = 0;
1182 		    if (arg == argv[0]) argv++, argc--;
1183 		    break;
1184 		} else
1185 		    goto usage;
1186 	      case 'q':			/* Number of query retries */
1187 		if (arg && isdigit((unsigned char)*arg)) {
1188 		    nqueries = atoi(arg);
1189 		    if (nqueries < 1) nqueries = 1;
1190 		    if (arg == argv[0]) argv++, argc--;
1191 		    break;
1192 		} else
1193 		    goto usage;
1194 	      case 'g':			/* Last-hop gateway (dest of query) */
1195 		if (arg && (gwy = host_addr(arg))) {
1196 		    if (arg == argv[0]) argv++, argc--;
1197 		    break;
1198 		} else
1199 		    goto usage;
1200 	      case 't':			/* TTL for query packet */
1201 		if (arg && isdigit((unsigned char)*arg)) {
1202 		    qttl = atoi(arg);
1203 		    if (qttl < 1) qttl = 1;
1204 		    rttl = qttl;
1205 		    if (arg == argv[0]) argv++, argc--;
1206 		    break;
1207 		} else
1208 		    goto usage;
1209 	      case 'r':			/* Dest for response packet */
1210 		if (arg && (raddr = host_addr(arg))) {
1211 		    if (arg == argv[0]) argv++, argc--;
1212 		    break;
1213 		} else
1214 		    goto usage;
1215 	      case 'i':			/* Local interface address */
1216 		if (arg && (lcl_addr = host_addr(arg))) {
1217 		    if (arg == argv[0]) argv++, argc--;
1218 		    break;
1219 		} else
1220 		    goto usage;
1221 	      case 'S':			/* Stat accumulation interval */
1222 		if (arg && isdigit((unsigned char)*arg)) {
1223 		    statint = atoi(arg);
1224 		    if (statint < 1) statint = 1;
1225 		    if (arg == argv[0]) argv++, argc--;
1226 		    break;
1227 		} else
1228 		    goto usage;
1229 	      default:
1230 		goto usage;
1231 	    }
1232 	} while (*p);
1233     }
1234 
1235     if (argc > 0 && (qsrc = host_addr(argv[0]))) {          /* Source of path */
1236 	if (IN_MULTICAST(ntohl(qsrc))) goto usage;
1237 	argv++, argc--;
1238 	if (argc > 0 && (qdst = host_addr(argv[0]))) {      /* Dest of path */
1239 	    argv++, argc--;
1240 	    if (argc > 0 && (qgrp = host_addr(argv[0]))) {  /* Path via group */
1241 		argv++, argc--;
1242 	    }
1243 	    if (IN_MULTICAST(ntohl(qdst))) {
1244 		u_int32_t temp = qdst;
1245 		qdst = qgrp;
1246 		qgrp = temp;
1247 		if (IN_MULTICAST(ntohl(qdst))) goto usage;
1248 	    } else if (qgrp && !IN_MULTICAST(ntohl(qgrp))) goto usage;
1249 	}
1250     }
1251 
1252     if (passive) {
1253 	passive_mode();
1254 	return(0);
1255     }
1256 
1257     if (argc > 0 || qsrc == 0) {
1258 usage:	printf("\
1259 usage: mtrace [-lMnpsv] [-g gateway] [-i if_addr] [-m max_hops] [-q nqueries]\n\
1260               [-r host] [-S stat_int] [-t ttl] [-w waittime] source [receiver]\n\
1261 	      [group]\n");
1262 	exit(1);
1263     }
1264 
1265     /*
1266      * Set useful defaults for as many parameters as possible.
1267      */
1268 
1269     defgrp = htonl(0xE0020001);		/* MBone Audio (224.2.0.1) */
1270     query_cast = htonl(0xE0000002);	/* All routers multicast addr */
1271     resp_cast = htonl(0xE0000120);	/* Mtrace response multicast addr */
1272     if (qgrp == 0) qgrp = defgrp;
1273 
1274     /*
1275      * Get default local address for multicasts to use in setting defaults.
1276      */
1277     memset(&addr, 0, sizeof addr);
1278     addr.sin_family = AF_INET;
1279     addr.sin_len = sizeof(addr);
1280     addr.sin_addr.s_addr = qgrp;
1281     addr.sin_port = htons(2000);	/* Any port above 1024 will do */
1282 
1283     if (((udp = socket(AF_INET, SOCK_DGRAM, 0)) == -1) ||
1284 	(connect(udp, (struct sockaddr *) &addr, sizeof(addr)) == -1) ||
1285 	getsockname(udp, (struct sockaddr *) &addr, &addrlen) == -1) {
1286 	perror("Determining local address");
1287 	exit(1);
1288     }
1289 
1290 #ifdef SUNOS5
1291    /*
1292      * SunOS 5.X prior to SunOS 2.6, getsockname returns 0 for udp socket.
1293      * This call to sysinfo will return the hostname.
1294      * If the default multicast interface (set with the route
1295      * for 224.0.0.0) is not the same as the hostname,
1296      * mtrace -i [if_addr] will have to be used.
1297      */
1298     if (addr.sin_addr.s_addr == 0) {
1299 	char myhostname[HOST_NAME_MAX+1];
1300 	struct hostent *hp;
1301 	int error;
1302 
1303 	error = sysinfo(SI_HOSTNAME, myhostname, sizeof(myhostname));
1304 	if (error == -1) {
1305 	    perror("Getting my hostname");
1306 	    exit(1);
1307 	}
1308 
1309 	hp = gethostbyname(myhostname);
1310 	if (hp == NULL || hp->h_addrtype != AF_INET ||
1311 	    hp->h_length != sizeof(addr.sin_addr)) {
1312 	    perror("Finding IP address for my hostname");
1313 	    exit(1);
1314 	}
1315 
1316 	memcpy((char *)&addr.sin_addr.s_addr, hp->h_addr, hp->h_length);
1317     }
1318 #endif
1319 
1320     /*
1321      * Default destination for path to be queried is the local host.
1322      */
1323     if (qdst == 0) qdst = lcl_addr ? lcl_addr : addr.sin_addr.s_addr;
1324     dst_netmask = get_netmask(udp, qdst);
1325     close(udp);
1326     if (lcl_addr == 0) lcl_addr = addr.sin_addr.s_addr;
1327 
1328     /*
1329      * Protect against unicast queries to mrouted versions that might crash.
1330      */
1331     if (gwy && !IN_MULTICAST(ntohl(gwy)))
1332       if (send_recv(gwy, IGMP_DVMRP, DVMRP_ASK_NEIGHBORS2, 1, &incr[0])) {
1333 	  int version = ntohl(incr[0].igmp.igmp_group.s_addr) & 0xFFFF;
1334 	  if (version == 0x0303 || version == 0x0503) {
1335 	    printf("Don't use -g to address an mrouted 3.%d, it might crash\n",
1336 		   (version >> 8) & 0xFF);
1337 	    exit(0);
1338 	}
1339       }
1340 
1341     printf("Mtrace from %s to %s via group %s\n",
1342 	   inet_fmt(qsrc, s1), inet_fmt(qdst, s2), inet_fmt(qgrp, s3));
1343 
1344     if ((qdst & dst_netmask) == (qsrc & dst_netmask)) {
1345 	printf("Source & receiver are directly connected, no path to trace\n");
1346 	exit(0);
1347     }
1348 
1349     /*
1350      * If the response is to be a multicast address, make sure we
1351      * are listening on that multicast address.
1352      */
1353     if (raddr) {
1354 	if (IN_MULTICAST(ntohl(raddr))) k_join(raddr, lcl_addr);
1355     } else k_join(resp_cast, lcl_addr);
1356 
1357     /*
1358      * If the destination is on the local net, the last-hop router can
1359      * be found by multicast to the all-routers multicast group.
1360      * Otherwise, use the group address that is the subject of the
1361      * query since by definition the last-hop router will be a member.
1362      * Set default TTLs for local remote multicasts.
1363      */
1364     restart:
1365 
1366     if (gwy == 0)
1367       if ((qdst & dst_netmask) == (lcl_addr & dst_netmask)) tdst = query_cast;
1368       else tdst = qgrp;
1369     else tdst = gwy;
1370 
1371     if (IN_MULTICAST(ntohl(tdst))) {
1372       k_set_loop(1);	/* If I am running on a router, I need to hear this */
1373       if (tdst == query_cast) k_set_ttl(qttl ? qttl : 1);
1374       else k_set_ttl(qttl ? qttl : MULTICAST_TTL1);
1375     }
1376 
1377     /*
1378      * Try a query at the requested number of hops or MAXHOPS if unspecified.
1379      */
1380     if (qno == 0) {
1381 	hops = MAXHOPS;
1382 	tries = 1;
1383 	printf("Querying full reverse path... ");
1384 	fflush(stdout);
1385     } else {
1386 	hops = qno;
1387 	tries = nqueries;
1388 	printf("Querying reverse path, maximum %d hops... ", qno);
1389 	fflush(stdout);
1390     }
1391     base.rtime = 0;
1392     base.len = 0;
1393 
1394     recvlen = send_recv(tdst, IGMP_MTRACE_QUERY, hops, tries, &base);
1395 
1396     /*
1397      * If the initial query was successful, print it.  Otherwise, if
1398      * the query max hop count is the default of zero, loop starting
1399      * from one until there is no response for four hops.  The extra
1400      * hops allow getting past an mtrace-capable mrouter that can't
1401      * send multicast packets because all phyints are disabled.
1402      */
1403     if (recvlen) {
1404 	printf("\n  0  ");
1405 	print_host(qdst);
1406 	printf("\n");
1407 	print_trace(1, &base);
1408 	r = base.resps + base.len - 1;
1409 	if (r->tr_rflags == TR_OLD_ROUTER || r->tr_rflags == TR_NO_SPACE ||
1410 		qno != 0) {
1411 	    printf("%3d  ", -(base.len+1));
1412 	    what_kind(&base, r->tr_rflags == TR_OLD_ROUTER ?
1413 				   "doesn't support mtrace"
1414 				 : "is the next hop");
1415 	} else {
1416 	    VAL_TO_MASK(smask, r->tr_smask);
1417 	    if ((r->tr_inaddr & smask) == (qsrc & smask)) {
1418 		printf("%3d  ", -(base.len+1));
1419 		print_host(qsrc);
1420 		printf("\n");
1421 	    }
1422 	}
1423     } else if (qno == 0) {
1424 	printf("switching to hop-by-hop:\n  0  ");
1425 	print_host(qdst);
1426 	printf("\n");
1427 
1428 	for (hops = 1, nexthop = 1; hops <= MAXHOPS; ++hops) {
1429 	    printf("%3d  ", -hops);
1430 	    fflush(stdout);
1431 
1432 	    /*
1433 	     * After a successful first hop, try switching to the unicast
1434 	     * address of the last-hop router instead of multicasting the
1435 	     * trace query.  This should be safe for mrouted versions 3.3
1436 	     * and 3.5 because there is a long route timeout with metric
1437 	     * infinity before a route disappears.  Switching to unicast
1438 	     * reduces the amount of multicast traffic and avoids a bug
1439 	     * with duplicate suppression in mrouted 3.5.
1440 	     */
1441 	    if (hops == 2 && gwy == 0 &&
1442 		(recvlen = send_recv(lastout, IGMP_MTRACE_QUERY, hops, 1, &base)))
1443 	      tdst = lastout;
1444 	    else recvlen = send_recv(tdst, IGMP_MTRACE_QUERY, hops, nqueries, &base);
1445 
1446 	    if (recvlen == 0) {
1447 		if (hops == 1) break;
1448 		if (hops == nexthop) {
1449 		    if (what_kind(&base, "didn't respond")) {
1450 			/* the ask_neighbors determined that the
1451 			 * not-responding router is the first-hop. */
1452 			break;
1453 		    }
1454 		} else if (hops < nexthop + 3) {
1455 		    printf("\n");
1456 		} else {
1457 		    printf("...giving up\n");
1458 		    break;
1459 		}
1460 		continue;
1461 	    }
1462 	    r = base.resps + base.len - 1;
1463 	    if (base.len == hops &&
1464 		(hops == 1 || (base.resps+nexthop-2)->tr_outaddr == lastout)) {
1465 		if (hops == nexthop) {
1466 		    print_trace(-hops, &base);
1467 		} else {
1468 		    printf("\nResuming...\n");
1469 		    print_trace(nexthop, &base);
1470 		}
1471 	    } else {
1472 		if (base.len < hops) {
1473 		    /*
1474 		     * A shorter trace than requested means a fatal error
1475 		     * occurred along the path, or that the route changed
1476 		     * to a shorter one.
1477 		     *
1478 		     * If the trace is longer than the last one we received,
1479 		     * then we are resuming from a skipped router (but there
1480 		     * is still probably a problem).
1481 		     *
1482 		     * If the trace is shorter than the last one we
1483 		     * received, then the route must have changed (and
1484 		     * there is still probably a problem).
1485 		     */
1486 		    if (nexthop <= base.len) {
1487 			printf("\nResuming...\n");
1488 			print_trace(nexthop, &base);
1489 		    } else if (nexthop > base.len + 1) {
1490 			hops = base.len;
1491 			printf("\nRoute must have changed...\n");
1492 			print_trace(1, &base);
1493 		    }
1494 		} else {
1495 		    /*
1496 		     * The last hop address is not the same as it was;
1497 		     * the route probably changed underneath us.
1498 		     */
1499 		    hops = base.len;
1500 		    printf("\nRoute must have changed...\n");
1501 		    print_trace(1, &base);
1502 		}
1503 	    }
1504 	    lastout = r->tr_outaddr;
1505 
1506 	    if (base.len < hops ||
1507 		r->tr_rmtaddr == 0 ||
1508 		(r->tr_rflags & 0x80)) {
1509 		VAL_TO_MASK(smask, r->tr_smask);
1510 		if (r->tr_rmtaddr) {
1511 		    if (hops != nexthop) {
1512 			printf("\n%3d  ", -(base.len+1));
1513 		    }
1514 		    what_kind(&base, r->tr_rflags == TR_OLD_ROUTER ?
1515 				"doesn't support mtrace" :
1516 				"would be the next hop");
1517 		    /* XXX could do segmented trace if TR_NO_SPACE */
1518 		} else if (r->tr_rflags == TR_NO_ERR &&
1519 			   (r->tr_inaddr & smask) == (qsrc & smask)) {
1520 		    printf("%3d  ", -(hops + 1));
1521 		    print_host(qsrc);
1522 		    printf("\n");
1523 		}
1524 		break;
1525 	    }
1526 
1527 	    nexthop = hops + 1;
1528 	}
1529     }
1530 
1531     if (base.rtime == 0) {
1532 	printf("Timed out receiving responses\n");
1533 	if (IN_MULTICAST(ntohl(tdst))) {
1534 	  if (tdst == query_cast)
1535 	    printf("Perhaps no local router has a route for source %s\n",
1536 		   inet_fmt(qsrc, s1));
1537 	  else
1538 	    printf("Perhaps receiver %s is not a member of group %s,\n\
1539 or no router local to it has a route for source %s,\n\
1540 or multicast at ttl %d doesn't reach its last-hop router for that source\n",
1541 		   inet_fmt(qdst, s2), inet_fmt(qgrp, s3), inet_fmt(qsrc, s1),
1542 		   qttl ? qttl : MULTICAST_TTL1);
1543 	}
1544 	exit(1);
1545     }
1546 
1547     printf("Round trip time %d ms\n\n", t_diff(base.rtime, base.qtime));
1548 
1549     /*
1550      * Use the saved response which was the longest one received,
1551      * and make additional probes after delay to measure loss.
1552      */
1553     raddr = base.qhdr.tr_raddr;
1554     rttl = base.qhdr.tr_rttl;
1555     gettimeofday(&tv, 0);
1556     waittime = statint - (((tv.tv_sec + JAN_1970) & 0xFFFF) - (base.qtime >> 16));
1557     prev = &base;
1558     new = &incr[numstats&1];
1559 
1560     while (numstats--) {
1561 	if (waittime < 1)
1562 		printf("\n");
1563 	else {
1564 		printf("Waiting to accumulate statistics... ");
1565 		fflush(stdout);
1566 		sleep((unsigned int)waittime);
1567 	}
1568 	rno = base.len;
1569 	recvlen = send_recv(tdst, IGMP_MTRACE_QUERY, rno, nqueries, new);
1570 
1571 	if (recvlen == 0) {
1572 	    printf("Timed out.\n");
1573 	    exit(1);
1574 	}
1575 
1576 	if (rno != new->len) {
1577 	    printf("Trace length doesn't match:\n");
1578 	    /*
1579 	     * XXX Should this trace result be printed, or is that
1580 	     * too verbose?  Perhaps it should just say restarting.
1581 	     * But if the path is changing quickly, this may be the
1582 	     * only snapshot of the current path.  But, if the path
1583 	     * is changing that quickly, does the current path really
1584 	     * matter?
1585 	     */
1586 	    print_trace(1, new);
1587 	    printf("Restarting.\n\n");
1588 	    numstats++;
1589 	    goto restart;
1590 	}
1591 
1592 	printf("Results after %d seconds:\n\n",
1593 	       (int)((new->qtime - base.qtime) >> 16));
1594 	fixup_stats(&base, prev, new);
1595 	if (print_stats(&base, prev, new)) {
1596 	    printf("Route changed:\n");
1597 	    print_trace(1, new);
1598 	    printf("Restarting.\n\n");
1599 	    goto restart;
1600 	}
1601 	prev = new;
1602 	new = &incr[numstats&1];
1603 	waittime = statint;
1604     }
1605 
1606     /*
1607      * If the response was multicast back, leave the group
1608      */
1609     if (raddr) {
1610 	if (IN_MULTICAST(ntohl(raddr)))	k_leave(raddr, lcl_addr);
1611     } else k_leave(resp_cast, lcl_addr);
1612 
1613     return (0);
1614 }
1615 
1616 void
1617 check_vif_state(void)
1618 {
1619     logit(LOG_WARNING, errno, "sendto");
1620 }
1621 
1622 /*
1623  * Log errors and other messages to stderr, according to the severity
1624  * of the message and the current debug level.  For errors of severity
1625  * LOG_ERR or worse, terminate the program.
1626  */
1627 void
1628 logit(int severity, int syserr, char *format, ...)
1629 {
1630     va_list ap;
1631 
1632     switch (debug) {
1633 	case 0: if (severity > LOG_WARNING) return;
1634 	case 1: if (severity > LOG_NOTICE) return;
1635 	case 2: if (severity > LOG_INFO  ) return;
1636 	default:
1637 	    if (severity == LOG_WARNING)
1638 		fprintf(stderr, "warning - ");
1639 	    va_start(ap, format);
1640 	    vfprintf(stderr, format, ap);
1641 	    va_end(ap);
1642 	    if (syserr == 0)
1643 		fprintf(stderr, "\n");
1644 	    else if(syserr < sys_nerr)
1645 		fprintf(stderr, ": %s\n", sys_errlist[syserr]);
1646 	    else
1647 		fprintf(stderr, ": errno %d\n", syserr);
1648     }
1649     if (severity <= LOG_ERR) exit(1);
1650 }
1651 
1652 /* dummies */
1653 void accept_probe(u_int32_t src, u_int32_t dst, char *p, int datalen,
1654     u_int32_t level)
1655 {
1656 }
1657 
1658 void accept_group_report(u_int32_t src, u_int32_t dst, u_int32_t group,
1659     int r_type)
1660 {
1661 }
1662 
1663 void accept_neighbor_request2(u_int32_t src, u_int32_t dst)
1664 {
1665 }
1666 
1667 void accept_report(u_int32_t src, u_int32_t dst, char *p, int datalen,
1668     u_int32_t level)
1669 {
1670 }
1671 
1672 void accept_neighbor_request(u_int32_t src, u_int32_t dst)
1673 {
1674 }
1675 
1676 void accept_prune(u_int32_t src, u_int32_t dst, char *p, int datalen)
1677 {
1678 }
1679 
1680 void accept_graft(u_int32_t src, u_int32_t dst, char *p, int datalen)
1681 {
1682 }
1683 
1684 void accept_g_ack(u_int32_t src, u_int32_t dst, char *p, int datalen)
1685 {
1686 }
1687 
1688 void add_table_entry(u_int32_t origin, u_int32_t mcastgrp)
1689 {
1690 }
1691 
1692 void accept_leave_message(u_int32_t src, u_int32_t dst, u_int32_t group)
1693 {
1694 }
1695 
1696 void accept_mtrace(u_int32_t src, u_int32_t dst, u_int32_t group, char *data,
1697     u_int no, int datalen)
1698 {
1699 }
1700 
1701 void accept_membership_query(u_int32_t src, u_int32_t dst, u_int32_t group,
1702     int tmo)
1703 {
1704 }
1705 
1706 void accept_neighbors(u_int32_t src, u_int32_t dst, u_char *p, int datalen,
1707     u_int32_t level)
1708 {
1709 }
1710 
1711 void accept_neighbors2(u_int32_t src, u_int32_t dst, u_char *p, int datalen,
1712     u_int32_t level)
1713 {
1714 }
1715 
1716 void accept_info_request(u_int32_t src, u_int32_t dst, u_char *p, int datalen)
1717 {
1718 }
1719 
1720 void accept_info_reply(u_int32_t src, u_int32_t dst, u_char *p, int datalen)
1721 {
1722 }
1723