1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * 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 char copyright[] = 13 "@(#) Copyright (c) 1990 The Regents of the University of California.\n\ 14 All rights reserved.\n"; 15 #endif /* not lint */ 16 17 #ifndef lint 18 static char sccsid[] = "@(#)traceroute.c 5.5 (Berkeley) 05/26/92"; 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 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; 394 395 ident = (getpid() & 0xffff) | 0x8000; 396 397 if ((pe = getprotobyname("icmp")) == NULL) { 398 Fprintf(stderr, "icmp: unknown protocol\n"); 399 exit(10); 400 } 401 if ((s = socket(AF_INET, SOCK_RAW, pe->p_proto)) < 0) { 402 perror("traceroute: icmp socket"); 403 exit(5); 404 } 405 if (options & SO_DEBUG) 406 (void) setsockopt(s, SOL_SOCKET, SO_DEBUG, 407 (char *)&on, sizeof(on)); 408 if (options & SO_DONTROUTE) 409 (void) setsockopt(s, SOL_SOCKET, SO_DONTROUTE, 410 (char *)&on, sizeof(on)); 411 412 if ((sndsock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) { 413 perror("traceroute: raw socket"); 414 exit(5); 415 } 416 #ifdef SO_SNDBUF 417 if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, (char *)&datalen, 418 sizeof(datalen)) < 0) { 419 perror("traceroute: SO_SNDBUF"); 420 exit(6); 421 } 422 #endif SO_SNDBUF 423 #ifdef IP_HDRINCL 424 if (setsockopt(sndsock, IPPROTO_IP, IP_HDRINCL, (char *)&on, 425 sizeof(on)) < 0) { 426 perror("traceroute: IP_HDRINCL"); 427 exit(6); 428 } 429 #endif IP_HDRINCL 430 if (options & SO_DEBUG) 431 (void) setsockopt(sndsock, SOL_SOCKET, SO_DEBUG, 432 (char *)&on, sizeof(on)); 433 if (options & SO_DONTROUTE) 434 (void) setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE, 435 (char *)&on, sizeof(on)); 436 437 if (source) { 438 (void) bzero((char *)&from, sizeof(struct sockaddr)); 439 from.sin_family = AF_INET; 440 from.sin_addr.s_addr = inet_addr(source); 441 if (from.sin_addr.s_addr == -1) { 442 Printf("traceroute: unknown host %s\n", source); 443 exit(1); 444 } 445 outpacket->ip.ip_src = from.sin_addr; 446 #ifndef IP_HDRINCL 447 if (bind(sndsock, (struct sockaddr *)&from, sizeof(from)) < 0) { 448 perror ("traceroute: bind:"); 449 exit (1); 450 } 451 #endif IP_HDRINCL 452 } 453 454 Fprintf(stderr, "traceroute to %s (%s)", hostname, 455 inet_ntoa(to->sin_addr)); 456 if (source) 457 Fprintf(stderr, " from %s", source); 458 Fprintf(stderr, ", %d hops max, %d byte packets\n", max_ttl, datalen); 459 (void) fflush(stderr); 460 461 for (ttl = 1; ttl <= max_ttl; ++ttl) { 462 u_long lastaddr = 0; 463 int got_there = 0; 464 int unreachable = 0; 465 466 Printf("%2d ", ttl); 467 for (probe = 0; probe < nprobes; ++probe) { 468 int cc; 469 struct timeval t1, t2; 470 struct timezone tz; 471 struct ip *ip; 472 473 (void) gettimeofday(&t1, &tz); 474 send_probe(++seq, ttl); 475 while (cc = wait_for_reply(s, &from)) { 476 (void) gettimeofday(&t2, &tz); 477 if ((i = packet_ok(packet, cc, &from, seq))) { 478 if (from.sin_addr.s_addr != lastaddr) { 479 print(packet, cc, &from); 480 lastaddr = from.sin_addr.s_addr; 481 } 482 Printf(" %g ms", deltaT(&t1, &t2)); 483 switch(i - 1) { 484 case ICMP_UNREACH_PORT: 485 #ifndef ARCHAIC 486 ip = (struct ip *)packet; 487 if (ip->ip_ttl <= 1) 488 Printf(" !"); 489 #endif ARCHAIC 490 ++got_there; 491 break; 492 case ICMP_UNREACH_NET: 493 ++unreachable; 494 Printf(" !N"); 495 break; 496 case ICMP_UNREACH_HOST: 497 ++unreachable; 498 Printf(" !H"); 499 break; 500 case ICMP_UNREACH_PROTOCOL: 501 ++got_there; 502 Printf(" !P"); 503 break; 504 case ICMP_UNREACH_NEEDFRAG: 505 ++unreachable; 506 Printf(" !F"); 507 break; 508 case ICMP_UNREACH_SRCFAIL: 509 ++unreachable; 510 Printf(" !S"); 511 break; 512 } 513 break; 514 } 515 } 516 if (cc == 0) 517 Printf(" *"); 518 (void) fflush(stdout); 519 } 520 putchar('\n'); 521 if (got_there || unreachable >= nprobes-1) 522 exit(0); 523 } 524 } 525 526 int 527 wait_for_reply(sock, from) 528 int sock; 529 struct sockaddr_in *from; 530 { 531 fd_set fds; 532 struct timeval wait; 533 int cc = 0; 534 int fromlen = sizeof (*from); 535 536 FD_ZERO(&fds); 537 FD_SET(sock, &fds); 538 wait.tv_sec = waittime; wait.tv_usec = 0; 539 540 if (select(sock+1, &fds, (fd_set *)0, (fd_set *)0, &wait) > 0) 541 cc=recvfrom(s, (char *)packet, sizeof(packet), 0, 542 (struct sockaddr *)from, &fromlen); 543 544 return(cc); 545 } 546 547 548 void 549 send_probe(seq, ttl) 550 int seq, ttl; 551 { 552 struct opacket *op = outpacket; 553 struct ip *ip = &op->ip; 554 struct udphdr *up = &op->udp; 555 int i; 556 557 ip->ip_off = 0; 558 ip->ip_p = IPPROTO_UDP; 559 ip->ip_len = datalen; 560 ip->ip_ttl = ttl; 561 562 up->uh_sport = htons(ident); 563 up->uh_dport = htons(port+seq); 564 up->uh_ulen = htons((u_short)(datalen - sizeof(struct ip))); 565 up->uh_sum = 0; 566 567 op->seq = seq; 568 op->ttl = ttl; 569 (void) gettimeofday(&op->tv, &tz); 570 571 i = sendto(sndsock, (char *)outpacket, datalen, 0, &whereto, 572 sizeof(struct sockaddr)); 573 if (i < 0 || i != datalen) { 574 if (i<0) 575 perror("sendto"); 576 Printf("traceroute: wrote %s %d chars, ret=%d\n", hostname, 577 datalen, i); 578 (void) fflush(stdout); 579 } 580 } 581 582 583 double 584 deltaT(t1p, t2p) 585 struct timeval *t1p, *t2p; 586 { 587 register double dt; 588 589 dt = (double)(t2p->tv_sec - t1p->tv_sec) * 1000.0 + 590 (double)(t2p->tv_usec - t1p->tv_usec) / 1000.0; 591 return (dt); 592 } 593 594 595 /* 596 * Convert an ICMP "type" field to a printable string. 597 */ 598 char * 599 pr_type(t) 600 u_char t; 601 { 602 static char *ttab[] = { 603 "Echo Reply", "ICMP 1", "ICMP 2", "Dest Unreachable", 604 "Source Quench", "Redirect", "ICMP 6", "ICMP 7", 605 "Echo", "ICMP 9", "ICMP 10", "Time Exceeded", 606 "Param Problem", "Timestamp", "Timestamp Reply", "Info Request", 607 "Info Reply" 608 }; 609 610 if(t > 16) 611 return("OUT-OF-RANGE"); 612 613 return(ttab[t]); 614 } 615 616 617 int 618 packet_ok(buf, cc, from, seq) 619 u_char *buf; 620 int cc; 621 struct sockaddr_in *from; 622 int seq; 623 { 624 register struct icmp *icp; 625 u_char type, code; 626 int hlen; 627 #ifndef ARCHAIC 628 struct ip *ip; 629 630 ip = (struct ip *) buf; 631 hlen = ip->ip_hl << 2; 632 if (cc < hlen + ICMP_MINLEN) { 633 if (verbose) 634 Printf("packet too short (%d bytes) from %s\n", cc, 635 inet_ntoa(from->sin_addr)); 636 return (0); 637 } 638 cc -= hlen; 639 icp = (struct icmp *)(buf + hlen); 640 #else 641 icp = (struct icmp *)buf; 642 #endif ARCHAIC 643 type = icp->icmp_type; code = icp->icmp_code; 644 if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS) || 645 type == ICMP_UNREACH) { 646 struct ip *hip; 647 struct udphdr *up; 648 649 hip = &icp->icmp_ip; 650 hlen = hip->ip_hl << 2; 651 up = (struct udphdr *)((u_char *)hip + hlen); 652 if (hlen + 12 <= cc && hip->ip_p == IPPROTO_UDP && 653 up->uh_sport == htons(ident) && 654 up->uh_dport == htons(port+seq)) 655 return (type == ICMP_TIMXCEED? -1 : code+1); 656 } 657 #ifndef ARCHAIC 658 if (verbose) { 659 int i; 660 u_long *lp = (u_long *)&icp->icmp_ip; 661 662 Printf("\n%d bytes from %s to %s", cc, 663 inet_ntoa(from->sin_addr), inet_ntoa(ip->ip_dst)); 664 Printf(": icmp type %d (%s) code %d\n", type, pr_type(type), 665 icp->icmp_code); 666 for (i = 4; i < cc ; i += sizeof(long)) 667 Printf("%2d: x%8.8lx\n", i, *lp++); 668 } 669 #endif ARCHAIC 670 return(0); 671 } 672 673 674 void 675 print(buf, cc, from) 676 u_char *buf; 677 int cc; 678 struct sockaddr_in *from; 679 { 680 struct ip *ip; 681 int hlen; 682 683 ip = (struct ip *) buf; 684 hlen = ip->ip_hl << 2; 685 cc -= hlen; 686 687 if (nflag) 688 Printf(" %s", inet_ntoa(from->sin_addr)); 689 else 690 Printf(" %s (%s)", inetname(from->sin_addr), 691 inet_ntoa(from->sin_addr)); 692 693 if (verbose) 694 Printf (" %d bytes to %s", cc, inet_ntoa (ip->ip_dst)); 695 } 696 697 698 #ifdef notyet 699 /* 700 * Checksum routine for Internet Protocol family headers (C Version) 701 */ 702 u_short 703 in_cksum(addr, len) 704 u_short *addr; 705 int len; 706 { 707 register int nleft = len; 708 register u_short *w = addr; 709 register u_short answer; 710 register int sum = 0; 711 712 /* 713 * Our algorithm is simple, using a 32 bit accumulator (sum), 714 * we add sequential 16 bit words to it, and at the end, fold 715 * back all the carry bits from the top 16 bits into the lower 716 * 16 bits. 717 */ 718 while (nleft > 1) { 719 sum += *w++; 720 nleft -= 2; 721 } 722 723 /* mop up an odd byte, if necessary */ 724 if (nleft == 1) 725 sum += *(u_char *)w; 726 727 /* 728 * add back carry outs from top 16 bits to low 16 bits 729 */ 730 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ 731 sum += (sum >> 16); /* add carry */ 732 answer = ~sum; /* truncate to 16 bits */ 733 return (answer); 734 } 735 #endif notyet 736 737 /* 738 * Subtract 2 timeval structs: out = out - in. 739 * Out is assumed to be >= in. 740 */ 741 void 742 tvsub(out, in) 743 register struct timeval *out, *in; 744 { 745 if ((out->tv_usec -= in->tv_usec) < 0) { 746 out->tv_sec--; 747 out->tv_usec += 1000000; 748 } 749 out->tv_sec -= in->tv_sec; 750 } 751 752 753 /* 754 * Construct an Internet address representation. 755 * If the nflag has been supplied, give 756 * numeric value, otherwise try for symbolic name. 757 */ 758 char * 759 inetname(in) 760 struct in_addr in; 761 { 762 register char *cp; 763 static char line[50]; 764 struct hostent *hp; 765 static char domain[MAXHOSTNAMELEN + 1]; 766 static int first = 1; 767 768 if (first && !nflag) { 769 first = 0; 770 if (gethostname(domain, MAXHOSTNAMELEN) == 0 && 771 (cp = index(domain, '.'))) 772 (void) strcpy(domain, cp + 1); 773 else 774 domain[0] = 0; 775 } 776 cp = 0; 777 if (!nflag && in.s_addr != INADDR_ANY) { 778 hp = gethostbyaddr((char *)&in, sizeof (in), AF_INET); 779 if (hp) { 780 if ((cp = index(hp->h_name, '.')) && 781 !strcmp(cp + 1, domain)) 782 *cp = 0; 783 cp = hp->h_name; 784 } 785 } 786 if (cp) 787 (void) strcpy(line, cp); 788 else { 789 in.s_addr = ntohl(in.s_addr); 790 #define C(x) ((x) & 0xff) 791 Sprintf(line, "%lu.%lu.%lu.%lu", C(in.s_addr >> 24), 792 C(in.s_addr >> 16), C(in.s_addr >> 8), C(in.s_addr)); 793 } 794 return (line); 795 } 796 797 void 798 usage() 799 { 800 (void)fprintf(stderr, 801 "usage: traceroute [-dnrv] [-m max_ttl] [-p port#] [-q nqueries]\n\t\ 802 [-s src_addr] [-t tos] [-w wait] host [data size]\n"); 803 exit(1); 804 } 805