1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Van Jacobson.
7 *
8 * %sccs.include.redist.c%
9 */
10
11 #ifndef lint
12 static char copyright[] =
13 "@(#) Copyright (c) 1990, 1993\n\
14 The Regents of the University of California. All rights reserved.\n";
15 #endif /* not lint */
16
17 #ifndef lint
18 static char sccsid[] = "@(#)traceroute.c 8.1 (Berkeley) 06/06/93";
19 #endif /* not lint */
20
21 /*
22 * traceroute host - trace the route ip packets follow going to "host".
23 *
24 * Attempt to trace the route an ip packet would follow to some
25 * internet host. We find out intermediate hops by launching probe
26 * packets with a small ttl (time to live) then listening for an
27 * icmp "time exceeded" reply from a gateway. We start our probes
28 * with a ttl of one and increase by one until we get an icmp "port
29 * unreachable" (which means we got to "host") or hit a max (which
30 * defaults to 30 hops & can be changed with the -m flag). Three
31 * probes (change with -q flag) are sent at each ttl setting and a
32 * line is printed showing the ttl, address of the gateway and
33 * round trip time of each probe. If the probe answers come from
34 * different gateways, the address of each responding system will
35 * be printed. If there is no response within a 5 sec. timeout
36 * interval (changed with the -w flag), a "*" is printed for that
37 * probe.
38 *
39 * Probe packets are UDP format. We don't want the destination
40 * host to process them so the destination port is set to an
41 * unlikely value (if some clod on the destination is using that
42 * value, it can be changed with the -p flag).
43 *
44 * A sample use might be:
45 *
46 * [yak 71]% traceroute nis.nsf.net.
47 * traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 56 byte packet
48 * 1 helios.ee.lbl.gov (128.3.112.1) 19 ms 19 ms 0 ms
49 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
50 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
51 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 39 ms
52 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 39 ms 39 ms 39 ms
53 * 6 128.32.197.4 (128.32.197.4) 40 ms 59 ms 59 ms
54 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 59 ms
55 * 8 129.140.70.13 (129.140.70.13) 99 ms 99 ms 80 ms
56 * 9 129.140.71.6 (129.140.71.6) 139 ms 239 ms 319 ms
57 * 10 129.140.81.7 (129.140.81.7) 220 ms 199 ms 199 ms
58 * 11 nic.merit.edu (35.1.1.48) 239 ms 239 ms 239 ms
59 *
60 * Note that lines 2 & 3 are the same. This is due to a buggy
61 * kernel on the 2nd hop system -- lbl-csam.arpa -- that forwards
62 * packets with a zero ttl.
63 *
64 * A more interesting example is:
65 *
66 * [yak 72]% traceroute allspice.lcs.mit.edu.
67 * traceroute to allspice.lcs.mit.edu (18.26.0.115), 30 hops max
68 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
69 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms
70 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms
71 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms
72 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms
73 * 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms
74 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms
75 * 8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms
76 * 9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms
77 * 10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms
78 * 11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms
79 * 12 * * *
80 * 13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms
81 * 14 * * *
82 * 15 * * *
83 * 16 * * *
84 * 17 * * *
85 * 18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms
86 *
87 * (I start to see why I'm having so much trouble with mail to
88 * MIT.) Note that the gateways 12, 14, 15, 16 & 17 hops away
89 * either don't send ICMP "time exceeded" messages or send them
90 * with a ttl too small to reach us. 14 - 17 are running the
91 * MIT C Gateway code that doesn't send "time exceeded"s. God
92 * only knows what's going on with 12.
93 *
94 * The silent gateway 12 in the above may be the result of a bug in
95 * the 4.[23]BSD network code (and its derivatives): 4.x (x <= 3)
96 * sends an unreachable message using whatever ttl remains in the
97 * original datagram. Since, for gateways, the remaining ttl is
98 * zero, the icmp "time exceeded" is guaranteed to not make it back
99 * to us. The behavior of this bug is slightly more interesting
100 * when it appears on the destination system:
101 *
102 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
103 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 39 ms
104 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 39 ms 19 ms
105 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 19 ms
106 * 5 ccn-nerif35.Berkeley.EDU (128.32.168.35) 39 ms 39 ms 39 ms
107 * 6 csgw.Berkeley.EDU (128.32.133.254) 39 ms 59 ms 39 ms
108 * 7 * * *
109 * 8 * * *
110 * 9 * * *
111 * 10 * * *
112 * 11 * * *
113 * 12 * * *
114 * 13 rip.Berkeley.EDU (128.32.131.22) 59 ms ! 39 ms ! 39 ms !
115 *
116 * Notice that there are 12 "gateways" (13 is the final
117 * destination) and exactly the last half of them are "missing".
118 * What's really happening is that rip (a Sun-3 running Sun OS3.5)
119 * is using the ttl from our arriving datagram as the ttl in its
120 * icmp reply. So, the reply will time out on the return path
121 * (with no notice sent to anyone since icmp's aren't sent for
122 * icmp's) until we probe with a ttl that's at least twice the path
123 * length. I.e., rip is really only 7 hops away. A reply that
124 * returns with a ttl of 1 is a clue this problem exists.
125 * Traceroute prints a "!" after the time if the ttl is <= 1.
126 * Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or
127 * non-standard (HPUX) software, expect to see this problem
128 * frequently and/or take care picking the target host of your
129 * probes.
130 *
131 * Other possible annotations after the time are !H, !N, !P (got a host,
132 * network or protocol unreachable, respectively), !S or !F (source
133 * route failed or fragmentation needed -- neither of these should
134 * ever occur and the associated gateway is busted if you see one). If
135 * almost all the probes result in some kind of unreachable, traceroute
136 * will give up and exit.
137 *
138 * Notes
139 * -----
140 * This program must be run by root or be setuid. (I suggest that
141 * you *don't* make it setuid -- casual use could result in a lot
142 * of unnecessary traffic on our poor, congested nets.)
143 *
144 * This program requires a kernel mod that does not appear in any
145 * system available from Berkeley: A raw ip socket using proto
146 * IPPROTO_RAW must interpret the data sent as an ip datagram (as
147 * opposed to data to be wrapped in a ip datagram). See the README
148 * file that came with the source to this program for a description
149 * of the mods I made to /sys/netinet/raw_ip.c. Your mileage may
150 * vary. But, again, ANY 4.x (x < 4) BSD KERNEL WILL HAVE TO BE
151 * MODIFIED TO RUN THIS PROGRAM.
152 *
153 * The udp port usage may appear bizarre (well, ok, it is bizarre).
154 * The problem is that an icmp message only contains 8 bytes of
155 * data from the original datagram. 8 bytes is the size of a udp
156 * header so, if we want to associate replies with the original
157 * datagram, the necessary information must be encoded into the
158 * udp header (the ip id could be used but there's no way to
159 * interlock with the kernel's assignment of ip id's and, anyway,
160 * it would have taken a lot more kernel hacking to allow this
161 * code to set the ip id). So, to allow two or more users to
162 * use traceroute simultaneously, we use this task's pid as the
163 * source port (the high bit is set to move the port number out
164 * of the "likely" range). To keep track of which probe is being
165 * replied to (so times and/or hop counts don't get confused by a
166 * reply that was delayed in transit), we increment the destination
167 * port number before each probe.
168 *
169 * Don't use this as a coding example. I was trying to find a
170 * routing problem and this code sort-of popped out after 48 hours
171 * without sleep. I was amazed it ever compiled, much less ran.
172 *
173 * I stole the idea for this program from Steve Deering. Since
174 * the first release, I've learned that had I attended the right
175 * IETF working group meetings, I also could have stolen it from Guy
176 * Almes or Matt Mathis. I don't know (or care) who came up with
177 * the idea first. I envy the originators' perspicacity and I'm
178 * glad they didn't keep the idea a secret.
179 *
180 * Tim Seaver, Ken Adelman and C. Philip Wood provided bug fixes and/or
181 * enhancements to the original distribution.
182 *
183 * I've hacked up a round-trip-route version of this that works by
184 * sending a loose-source-routed udp datagram through the destination
185 * back to yourself. Unfortunately, SO many gateways botch source
186 * routing, the thing is almost worthless. Maybe one day...
187 *
188 * -- Van Jacobson (van@helios.ee.lbl.gov)
189 * Tue Dec 20 03:50:13 PST 1988
190 */
191
192 #include <sys/param.h>
193 #include <sys/time.h>
194 #include <sys/socket.h>
195 #include <sys/file.h>
196 #include <sys/ioctl.h>
197
198 #include <netinet/in_systm.h>
199 #include <netinet/in.h>
200 #include <netinet/ip.h>
201 #include <netinet/ip_icmp.h>
202 #include <netinet/udp.h>
203
204 #include <arpa/inet.h>
205
206 #include <netdb.h>
207 #include <stdio.h>
208 #include <errno.h>
209 #include <stdlib.h>
210 #include <string.h>
211 #include <unistd.h>
212
213 #define MAXPACKET 65535 /* max ip packet size */
214 #ifndef MAXHOSTNAMELEN
215 #define MAXHOSTNAMELEN 64
216 #endif
217
218 #ifndef FD_SET
219 #define NFDBITS (8*sizeof(fd_set))
220 #define FD_SETSIZE NFDBITS
221 #define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
222 #define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
223 #define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
224 #define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
225 #endif
226
227 #define Fprintf (void)fprintf
228 #define Sprintf (void)sprintf
229 #define Printf (void)printf
230
231 /*
232 * format of a (udp) probe packet.
233 */
234 struct opacket {
235 struct ip ip;
236 struct udphdr udp;
237 u_char seq; /* sequence number of this packet */
238 u_char ttl; /* ttl packet left with */
239 struct timeval tv; /* time packet left */
240 };
241
242 u_char packet[512]; /* last inbound (icmp) packet */
243 struct opacket *outpacket; /* last output (udp) packet */
244
245 int wait_for_reply __P((int, struct sockaddr_in *));
246 void send_probe __P((int, int));
247 double deltaT __P((struct timeval *, struct timeval *));
248 int packet_ok __P((u_char *, int, struct sockaddr_in *, int));
249 void print __P((u_char *, int, struct sockaddr_in *));
250 void tvsub __P((struct timeval *, struct timeval *));
251 char *inetname __P((struct in_addr));
252 void usage __P(());
253
254 int s; /* receive (icmp) socket file descriptor */
255 int sndsock; /* send (udp) socket file descriptor */
256 struct timezone tz; /* leftover */
257
258 struct sockaddr whereto; /* Who to try to reach */
259 int datalen; /* How much data */
260
261 char *source = 0;
262 char *hostname;
263
264 int nprobes = 3;
265 int max_ttl = 30;
266 u_short ident;
267 u_short port = 32768+666; /* start udp dest port # for probe packets */
268 int options; /* socket options */
269 int verbose;
270 int waittime = 5; /* time to wait for response (in seconds) */
271 int nflag; /* print addresses numerically */
272
273 int
main(argc,argv)274 main(argc, argv)
275 int argc;
276 char *argv[];
277 {
278 extern char *optarg;
279 extern int optind;
280 struct hostent *hp;
281 struct protoent *pe;
282 struct sockaddr_in from, *to;
283 int ch, i, on, probe, seq, tos, ttl;
284
285 on = 1;
286 seq = tos = 0;
287 to = (struct sockaddr_in *)&whereto;
288 while ((ch = getopt(argc, argv, "dm:np:q:rs:t:w:v")) != EOF)
289 switch(ch) {
290 case 'd':
291 options |= SO_DEBUG;
292 break;
293 case 'm':
294 max_ttl = atoi(optarg);
295 if (max_ttl <= 1) {
296 Fprintf(stderr,
297 "traceroute: max ttl must be >1.\n");
298 exit(1);
299 }
300 break;
301 case 'n':
302 nflag++;
303 break;
304 case 'p':
305 port = atoi(optarg);
306 if (port < 1) {
307 Fprintf(stderr,
308 "traceroute: port must be >0.\n");
309 exit(1);
310 }
311 break;
312 case 'q':
313 nprobes = atoi(optarg);
314 if (nprobes < 1) {
315 Fprintf(stderr,
316 "traceroute: nprobes must be >0.\n");
317 exit(1);
318 }
319 break;
320 case 'r':
321 options |= SO_DONTROUTE;
322 break;
323 case 's':
324 /*
325 * set the ip source address of the outbound
326 * probe (e.g., on a multi-homed host).
327 */
328 source = optarg;
329 break;
330 case 't':
331 tos = atoi(optarg);
332 if (tos < 0 || tos > 255) {
333 Fprintf(stderr,
334 "traceroute: tos must be 0 to 255.\n");
335 exit(1);
336 }
337 break;
338 case 'v':
339 verbose++;
340 break;
341 case 'w':
342 waittime = atoi(optarg);
343 if (waittime <= 1) {
344 Fprintf(stderr,
345 "traceroute: wait must be >1 sec.\n");
346 exit(1);
347 }
348 break;
349 default:
350 usage();
351 }
352 argc -= optind;
353 argv += optind;
354
355 if (argc < 1)
356 usage();
357
358 setlinebuf (stdout);
359
360 (void) bzero((char *)&whereto, sizeof(struct sockaddr));
361 to->sin_family = AF_INET;
362 to->sin_addr.s_addr = inet_addr(*argv);
363 if (to->sin_addr.s_addr != -1)
364 hostname = *argv;
365 else {
366 hp = gethostbyname(*argv);
367 if (hp) {
368 to->sin_family = hp->h_addrtype;
369 bcopy(hp->h_addr, (caddr_t)&to->sin_addr, hp->h_length);
370 hostname = hp->h_name;
371 } else {
372 (void)fprintf(stderr,
373 "traceroute: unknown host %s\n", *argv);
374 exit(1);
375 }
376 }
377 if (*++argv)
378 datalen = atoi(*argv);
379 if (datalen < 0 || datalen >= MAXPACKET - sizeof(struct opacket)) {
380 Fprintf(stderr,
381 "traceroute: packet size must be 0 <= s < %ld.\n",
382 MAXPACKET - sizeof(struct opacket));
383 exit(1);
384 }
385 datalen += sizeof(struct opacket);
386 outpacket = (struct opacket *)malloc((unsigned)datalen);
387 if (! outpacket) {
388 perror("traceroute: malloc");
389 exit(1);
390 }
391 (void) bzero((char *)outpacket, datalen);
392 outpacket->ip.ip_dst = to->sin_addr;
393 outpacket->ip.ip_tos = tos;
394 outpacket->ip.ip_v = IPVERSION;
395 outpacket->ip.ip_id = 0;
396
397 ident = (getpid() & 0xffff) | 0x8000;
398
399 if ((pe = getprotobyname("icmp")) == NULL) {
400 Fprintf(stderr, "icmp: unknown protocol\n");
401 exit(10);
402 }
403 if ((s = socket(AF_INET, SOCK_RAW, pe->p_proto)) < 0) {
404 perror("traceroute: icmp socket");
405 exit(5);
406 }
407 if (options & SO_DEBUG)
408 (void) setsockopt(s, SOL_SOCKET, SO_DEBUG,
409 (char *)&on, sizeof(on));
410 if (options & SO_DONTROUTE)
411 (void) setsockopt(s, SOL_SOCKET, SO_DONTROUTE,
412 (char *)&on, sizeof(on));
413
414 if ((sndsock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) {
415 perror("traceroute: raw socket");
416 exit(5);
417 }
418 #ifdef SO_SNDBUF
419 if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, (char *)&datalen,
420 sizeof(datalen)) < 0) {
421 perror("traceroute: SO_SNDBUF");
422 exit(6);
423 }
424 #endif SO_SNDBUF
425 #ifdef IP_HDRINCL
426 if (setsockopt(sndsock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
427 sizeof(on)) < 0) {
428 perror("traceroute: IP_HDRINCL");
429 exit(6);
430 }
431 #endif IP_HDRINCL
432 if (options & SO_DEBUG)
433 (void) setsockopt(sndsock, SOL_SOCKET, SO_DEBUG,
434 (char *)&on, sizeof(on));
435 if (options & SO_DONTROUTE)
436 (void) setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE,
437 (char *)&on, sizeof(on));
438
439 if (source) {
440 (void) bzero((char *)&from, sizeof(struct sockaddr));
441 from.sin_family = AF_INET;
442 from.sin_addr.s_addr = inet_addr(source);
443 if (from.sin_addr.s_addr == -1) {
444 Printf("traceroute: unknown host %s\n", source);
445 exit(1);
446 }
447 outpacket->ip.ip_src = from.sin_addr;
448 #ifndef IP_HDRINCL
449 if (bind(sndsock, (struct sockaddr *)&from, sizeof(from)) < 0) {
450 perror ("traceroute: bind:");
451 exit (1);
452 }
453 #endif IP_HDRINCL
454 }
455
456 Fprintf(stderr, "traceroute to %s (%s)", hostname,
457 inet_ntoa(to->sin_addr));
458 if (source)
459 Fprintf(stderr, " from %s", source);
460 Fprintf(stderr, ", %d hops max, %d byte packets\n", max_ttl, datalen);
461 (void) fflush(stderr);
462
463 for (ttl = 1; ttl <= max_ttl; ++ttl) {
464 u_long lastaddr = 0;
465 int got_there = 0;
466 int unreachable = 0;
467
468 Printf("%2d ", ttl);
469 for (probe = 0; probe < nprobes; ++probe) {
470 int cc;
471 struct timeval t1, t2;
472 struct timezone tz;
473 struct ip *ip;
474
475 (void) gettimeofday(&t1, &tz);
476 send_probe(++seq, ttl);
477 while (cc = wait_for_reply(s, &from)) {
478 (void) gettimeofday(&t2, &tz);
479 if ((i = packet_ok(packet, cc, &from, seq))) {
480 if (from.sin_addr.s_addr != lastaddr) {
481 print(packet, cc, &from);
482 lastaddr = from.sin_addr.s_addr;
483 }
484 Printf(" %g ms", deltaT(&t1, &t2));
485 switch(i - 1) {
486 case ICMP_UNREACH_PORT:
487 #ifndef ARCHAIC
488 ip = (struct ip *)packet;
489 if (ip->ip_ttl <= 1)
490 Printf(" !");
491 #endif ARCHAIC
492 ++got_there;
493 break;
494 case ICMP_UNREACH_NET:
495 ++unreachable;
496 Printf(" !N");
497 break;
498 case ICMP_UNREACH_HOST:
499 ++unreachable;
500 Printf(" !H");
501 break;
502 case ICMP_UNREACH_PROTOCOL:
503 ++got_there;
504 Printf(" !P");
505 break;
506 case ICMP_UNREACH_NEEDFRAG:
507 ++unreachable;
508 Printf(" !F");
509 break;
510 case ICMP_UNREACH_SRCFAIL:
511 ++unreachable;
512 Printf(" !S");
513 break;
514 }
515 break;
516 }
517 }
518 if (cc == 0)
519 Printf(" *");
520 (void) fflush(stdout);
521 }
522 putchar('\n');
523 if (got_there || unreachable >= nprobes-1)
524 exit(0);
525 }
526 }
527
528 int
wait_for_reply(sock,from)529 wait_for_reply(sock, from)
530 int sock;
531 struct sockaddr_in *from;
532 {
533 fd_set fds;
534 struct timeval wait;
535 int cc = 0;
536 int fromlen = sizeof (*from);
537
538 FD_ZERO(&fds);
539 FD_SET(sock, &fds);
540 wait.tv_sec = waittime; wait.tv_usec = 0;
541
542 if (select(sock+1, &fds, (fd_set *)0, (fd_set *)0, &wait) > 0)
543 cc=recvfrom(s, (char *)packet, sizeof(packet), 0,
544 (struct sockaddr *)from, &fromlen);
545
546 return(cc);
547 }
548
549
550 void
send_probe(seq,ttl)551 send_probe(seq, ttl)
552 int seq, ttl;
553 {
554 struct opacket *op = outpacket;
555 struct ip *ip = &op->ip;
556 struct udphdr *up = &op->udp;
557 int i;
558
559 ip->ip_off = 0;
560 ip->ip_hl = sizeof(*ip) >> 2;
561 ip->ip_p = IPPROTO_UDP;
562 ip->ip_len = datalen;
563 ip->ip_ttl = ttl;
564 ip->ip_v = IPVERSION;
565 ip->ip_id = htons(ident+seq);
566
567 up->uh_sport = htons(ident);
568 up->uh_dport = htons(port+seq);
569 up->uh_ulen = htons((u_short)(datalen - sizeof(struct ip)));
570 up->uh_sum = 0;
571
572 op->seq = seq;
573 op->ttl = ttl;
574 (void) gettimeofday(&op->tv, &tz);
575
576 i = sendto(sndsock, (char *)outpacket, datalen, 0, &whereto,
577 sizeof(struct sockaddr));
578 if (i < 0 || i != datalen) {
579 if (i<0)
580 perror("sendto");
581 Printf("traceroute: wrote %s %d chars, ret=%d\n", hostname,
582 datalen, i);
583 (void) fflush(stdout);
584 }
585 }
586
587
588 double
deltaT(t1p,t2p)589 deltaT(t1p, t2p)
590 struct timeval *t1p, *t2p;
591 {
592 register double dt;
593
594 dt = (double)(t2p->tv_sec - t1p->tv_sec) * 1000.0 +
595 (double)(t2p->tv_usec - t1p->tv_usec) / 1000.0;
596 return (dt);
597 }
598
599
600 /*
601 * Convert an ICMP "type" field to a printable string.
602 */
603 char *
pr_type(t)604 pr_type(t)
605 u_char t;
606 {
607 static char *ttab[] = {
608 "Echo Reply", "ICMP 1", "ICMP 2", "Dest Unreachable",
609 "Source Quench", "Redirect", "ICMP 6", "ICMP 7",
610 "Echo", "ICMP 9", "ICMP 10", "Time Exceeded",
611 "Param Problem", "Timestamp", "Timestamp Reply", "Info Request",
612 "Info Reply"
613 };
614
615 if(t > 16)
616 return("OUT-OF-RANGE");
617
618 return(ttab[t]);
619 }
620
621
622 int
packet_ok(buf,cc,from,seq)623 packet_ok(buf, cc, from, seq)
624 u_char *buf;
625 int cc;
626 struct sockaddr_in *from;
627 int seq;
628 {
629 register struct icmp *icp;
630 u_char type, code;
631 int hlen;
632 #ifndef ARCHAIC
633 struct ip *ip;
634
635 ip = (struct ip *) buf;
636 hlen = ip->ip_hl << 2;
637 if (cc < hlen + ICMP_MINLEN) {
638 if (verbose)
639 Printf("packet too short (%d bytes) from %s\n", cc,
640 inet_ntoa(from->sin_addr));
641 return (0);
642 }
643 cc -= hlen;
644 icp = (struct icmp *)(buf + hlen);
645 #else
646 icp = (struct icmp *)buf;
647 #endif ARCHAIC
648 type = icp->icmp_type; code = icp->icmp_code;
649 if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS) ||
650 type == ICMP_UNREACH) {
651 struct ip *hip;
652 struct udphdr *up;
653
654 hip = &icp->icmp_ip;
655 hlen = hip->ip_hl << 2;
656 up = (struct udphdr *)((u_char *)hip + hlen);
657 if (hlen + 12 <= cc && hip->ip_p == IPPROTO_UDP &&
658 up->uh_sport == htons(ident) &&
659 up->uh_dport == htons(port+seq))
660 return (type == ICMP_TIMXCEED? -1 : code+1);
661 }
662 #ifndef ARCHAIC
663 if (verbose) {
664 int i;
665 u_long *lp = (u_long *)&icp->icmp_ip;
666
667 Printf("\n%d bytes from %s to %s", cc,
668 inet_ntoa(from->sin_addr), inet_ntoa(ip->ip_dst));
669 Printf(": icmp type %d (%s) code %d\n", type, pr_type(type),
670 icp->icmp_code);
671 for (i = 4; i < cc ; i += sizeof(long))
672 Printf("%2d: x%8.8lx\n", i, *lp++);
673 }
674 #endif ARCHAIC
675 return(0);
676 }
677
678
679 void
print(buf,cc,from)680 print(buf, cc, from)
681 u_char *buf;
682 int cc;
683 struct sockaddr_in *from;
684 {
685 struct ip *ip;
686 int hlen;
687
688 ip = (struct ip *) buf;
689 hlen = ip->ip_hl << 2;
690 cc -= hlen;
691
692 if (nflag)
693 Printf(" %s", inet_ntoa(from->sin_addr));
694 else
695 Printf(" %s (%s)", inetname(from->sin_addr),
696 inet_ntoa(from->sin_addr));
697
698 if (verbose)
699 Printf (" %d bytes to %s", cc, inet_ntoa (ip->ip_dst));
700 }
701
702
703 #ifdef notyet
704 /*
705 * Checksum routine for Internet Protocol family headers (C Version)
706 */
707 u_short
in_cksum(addr,len)708 in_cksum(addr, len)
709 u_short *addr;
710 int len;
711 {
712 register int nleft = len;
713 register u_short *w = addr;
714 register u_short answer;
715 register int sum = 0;
716
717 /*
718 * Our algorithm is simple, using a 32 bit accumulator (sum),
719 * we add sequential 16 bit words to it, and at the end, fold
720 * back all the carry bits from the top 16 bits into the lower
721 * 16 bits.
722 */
723 while (nleft > 1) {
724 sum += *w++;
725 nleft -= 2;
726 }
727
728 /* mop up an odd byte, if necessary */
729 if (nleft == 1)
730 sum += *(u_char *)w;
731
732 /*
733 * add back carry outs from top 16 bits to low 16 bits
734 */
735 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
736 sum += (sum >> 16); /* add carry */
737 answer = ~sum; /* truncate to 16 bits */
738 return (answer);
739 }
740 #endif notyet
741
742 /*
743 * Subtract 2 timeval structs: out = out - in.
744 * Out is assumed to be >= in.
745 */
746 void
tvsub(out,in)747 tvsub(out, in)
748 register struct timeval *out, *in;
749 {
750 if ((out->tv_usec -= in->tv_usec) < 0) {
751 out->tv_sec--;
752 out->tv_usec += 1000000;
753 }
754 out->tv_sec -= in->tv_sec;
755 }
756
757
758 /*
759 * Construct an Internet address representation.
760 * If the nflag has been supplied, give
761 * numeric value, otherwise try for symbolic name.
762 */
763 char *
inetname(in)764 inetname(in)
765 struct in_addr in;
766 {
767 register char *cp;
768 static char line[50];
769 struct hostent *hp;
770 static char domain[MAXHOSTNAMELEN + 1];
771 static int first = 1;
772
773 if (first && !nflag) {
774 first = 0;
775 if (gethostname(domain, MAXHOSTNAMELEN) == 0 &&
776 (cp = index(domain, '.')))
777 (void) strcpy(domain, cp + 1);
778 else
779 domain[0] = 0;
780 }
781 cp = 0;
782 if (!nflag && in.s_addr != INADDR_ANY) {
783 hp = gethostbyaddr((char *)&in, sizeof (in), AF_INET);
784 if (hp) {
785 if ((cp = index(hp->h_name, '.')) &&
786 !strcmp(cp + 1, domain))
787 *cp = 0;
788 cp = hp->h_name;
789 }
790 }
791 if (cp)
792 (void) strcpy(line, cp);
793 else {
794 in.s_addr = ntohl(in.s_addr);
795 #define C(x) ((x) & 0xff)
796 Sprintf(line, "%lu.%lu.%lu.%lu", C(in.s_addr >> 24),
797 C(in.s_addr >> 16), C(in.s_addr >> 8), C(in.s_addr));
798 }
799 return (line);
800 }
801
802 void
usage()803 usage()
804 {
805 (void)fprintf(stderr,
806 "usage: traceroute [-dnrv] [-m max_ttl] [-p port#] [-q nqueries]\n\t\
807 [-s src_addr] [-t tos] [-w wait] host [data size]\n");
808 exit(1);
809 }
810