traceroute.c revision 1.15
1 /* $NetBSD: traceroute.c,v 1.15 1996/09/27 01:34:51 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Van Jacobson. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifndef lint 40 static char copyright[] = 41 "@(#) Copyright (c) 1990, 1993\n\ 42 The Regents of the University of California. All rights reserved.\n"; 43 #endif /* not lint */ 44 45 #ifndef lint 46 #if 0 47 static char sccsid[] = "@(#)traceroute.c 8.1 (Berkeley) 6/6/93";*/ 48 #else 49 static char rcsid[] = "$NetBSD: traceroute.c,v 1.15 1996/09/27 01:34:51 thorpej Exp $"; 50 #endif 51 #endif /* not lint */ 52 53 /* 54 * traceroute host - trace the route ip packets follow going to "host". 55 * 56 * Attempt to trace the route an ip packet would follow to some 57 * internet host. We find out intermediate hops by launching probe 58 * packets with a small ttl (time to live) then listening for an 59 * icmp "time exceeded" reply from a gateway. We start our probes 60 * with a ttl of one and increase by one until we get an icmp "port 61 * unreachable" (which means we got to "host") or hit a max (which 62 * defaults to 30 hops & can be changed with the -m flag). Three 63 * probes (change with -q flag) are sent at each ttl setting and a 64 * line is printed showing the ttl, address of the gateway and 65 * round trip time of each probe. If the probe answers come from 66 * different gateways, the address of each responding system will 67 * be printed. If there is no response within a 5 sec. timeout 68 * interval (changed with the -w flag), a "*" is printed for that 69 * probe. 70 * 71 * Probe packets are UDP format. We don't want the destination 72 * host to process them so the destination port is set to an 73 * unlikely value (if some clod on the destination is using that 74 * value, it can be changed with the -p flag). 75 * 76 * A sample use might be: 77 * 78 * [yak 71]% traceroute nis.nsf.net. 79 * traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 56 byte packet 80 * 1 helios.ee.lbl.gov (128.3.112.1) 19 ms 19 ms 0 ms 81 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms 82 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms 83 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 39 ms 84 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 39 ms 39 ms 39 ms 85 * 6 128.32.197.4 (128.32.197.4) 40 ms 59 ms 59 ms 86 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 59 ms 87 * 8 129.140.70.13 (129.140.70.13) 99 ms 99 ms 80 ms 88 * 9 129.140.71.6 (129.140.71.6) 139 ms 239 ms 319 ms 89 * 10 129.140.81.7 (129.140.81.7) 220 ms 199 ms 199 ms 90 * 11 nic.merit.edu (35.1.1.48) 239 ms 239 ms 239 ms 91 * 92 * Note that lines 2 & 3 are the same. This is due to a buggy 93 * kernel on the 2nd hop system -- lbl-csam.arpa -- that forwards 94 * packets with a zero ttl. 95 * 96 * A more interesting example is: 97 * 98 * [yak 72]% traceroute allspice.lcs.mit.edu. 99 * traceroute to allspice.lcs.mit.edu (18.26.0.115), 30 hops max 100 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms 101 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms 102 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms 103 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms 104 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms 105 * 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms 106 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms 107 * 8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms 108 * 9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms 109 * 10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms 110 * 11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms 111 * 12 * * * 112 * 13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms 113 * 14 * * * 114 * 15 * * * 115 * 16 * * * 116 * 17 * * * 117 * 18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms 118 * 119 * (I start to see why I'm having so much trouble with mail to 120 * MIT.) Note that the gateways 12, 14, 15, 16 & 17 hops away 121 * either don't send ICMP "time exceeded" messages or send them 122 * with a ttl too small to reach us. 14 - 17 are running the 123 * MIT C Gateway code that doesn't send "time exceeded"s. God 124 * only knows what's going on with 12. 125 * 126 * The silent gateway 12 in the above may be the result of a bug in 127 * the 4.[23]BSD network code (and its derivatives): 4.x (x <= 3) 128 * sends an unreachable message using whatever ttl remains in the 129 * original datagram. Since, for gateways, the remaining ttl is 130 * zero, the icmp "time exceeded" is guaranteed to not make it back 131 * to us. The behavior of this bug is slightly more interesting 132 * when it appears on the destination system: 133 * 134 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms 135 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 39 ms 136 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 39 ms 19 ms 137 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 19 ms 138 * 5 ccn-nerif35.Berkeley.EDU (128.32.168.35) 39 ms 39 ms 39 ms 139 * 6 csgw.Berkeley.EDU (128.32.133.254) 39 ms 59 ms 39 ms 140 * 7 * * * 141 * 8 * * * 142 * 9 * * * 143 * 10 * * * 144 * 11 * * * 145 * 12 * * * 146 * 13 rip.Berkeley.EDU (128.32.131.22) 59 ms ! 39 ms ! 39 ms ! 147 * 148 * Notice that there are 12 "gateways" (13 is the final 149 * destination) and exactly the last half of them are "missing". 150 * What's really happening is that rip (a Sun-3 running Sun OS3.5) 151 * is using the ttl from our arriving datagram as the ttl in its 152 * icmp reply. So, the reply will time out on the return path 153 * (with no notice sent to anyone since icmp's aren't sent for 154 * icmp's) until we probe with a ttl that's at least twice the path 155 * length. I.e., rip is really only 7 hops away. A reply that 156 * returns with a ttl of 1 is a clue this problem exists. 157 * Traceroute prints a "!" after the time if the ttl is <= 1. 158 * Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or 159 * non-standard (HPUX) software, expect to see this problem 160 * frequently and/or take care picking the target host of your 161 * probes. 162 * 163 * Other possible annotations after the time are !H, !N, !P (got a host, 164 * network or protocol unreachable, respectively), !S or !F (source 165 * route failed or fragmentation needed -- neither of these should 166 * ever occur and the associated gateway is busted if you see one). If 167 * almost all the probes result in some kind of unreachable, traceroute 168 * will give up and exit. 169 * 170 * Notes 171 * ----- 172 * This program must be run by root or be setuid. (I suggest that 173 * you *don't* make it setuid -- casual use could result in a lot 174 * of unnecessary traffic on our poor, congested nets.) 175 * 176 * This program requires a kernel mod that does not appear in any 177 * system available from Berkeley: A raw ip socket using proto 178 * IPPROTO_RAW must interpret the data sent as an ip datagram (as 179 * opposed to data to be wrapped in a ip datagram). See the README 180 * file that came with the source to this program for a description 181 * of the mods I made to /sys/netinet/raw_ip.c. Your mileage may 182 * vary. But, again, ANY 4.x (x < 4) BSD KERNEL WILL HAVE TO BE 183 * MODIFIED TO RUN THIS PROGRAM. 184 * 185 * The udp port usage may appear bizarre (well, ok, it is bizarre). 186 * The problem is that an icmp message only contains 8 bytes of 187 * data from the original datagram. 8 bytes is the size of a udp 188 * header so, if we want to associate replies with the original 189 * datagram, the necessary information must be encoded into the 190 * udp header (the ip id could be used but there's no way to 191 * interlock with the kernel's assignment of ip id's and, anyway, 192 * it would have taken a lot more kernel hacking to allow this 193 * code to set the ip id). So, to allow two or more users to 194 * use traceroute simultaneously, we use this task's pid as the 195 * source port (the high bit is set to move the port number out 196 * of the "likely" range). To keep track of which probe is being 197 * replied to (so times and/or hop counts don't get confused by a 198 * reply that was delayed in transit), we increment the destination 199 * port number before each probe. 200 * 201 * Don't use this as a coding example. I was trying to find a 202 * routing problem and this code sort-of popped out after 48 hours 203 * without sleep. I was amazed it ever compiled, much less ran. 204 * 205 * I stole the idea for this program from Steve Deering. Since 206 * the first release, I've learned that had I attended the right 207 * IETF working group meetings, I also could have stolen it from Guy 208 * Almes or Matt Mathis. I don't know (or care) who came up with 209 * the idea first. I envy the originators' perspicacity and I'm 210 * glad they didn't keep the idea a secret. 211 * 212 * Tim Seaver, Ken Adelman and C. Philip Wood provided bug fixes and/or 213 * enhancements to the original distribution. 214 * 215 * I've hacked up a round-trip-route version of this that works by 216 * sending a loose-source-routed udp datagram through the destination 217 * back to yourself. Unfortunately, SO many gateways botch source 218 * routing, the thing is almost worthless. Maybe one day... 219 * 220 * -- Van Jacobson (van (at) helios.ee.lbl.gov) 221 * Tue Dec 20 03:50:13 PST 1988 222 */ 223 224 #include <sys/param.h> 225 #include <sys/time.h> 226 #include <sys/socket.h> 227 #include <sys/file.h> 228 #include <sys/ioctl.h> 229 230 #include <netinet/in_systm.h> 231 #include <netinet/in.h> 232 #include <netinet/ip.h> 233 #include <netinet/ip_icmp.h> 234 #include <netinet/ip_var.h> 235 #include <netinet/udp.h> 236 237 #include <arpa/inet.h> 238 239 #include <ctype.h> 240 #include <err.h> 241 #include <errno.h> 242 #include <netdb.h> 243 #include <stdio.h> 244 #include <stdlib.h> 245 #include <string.h> 246 #include <unistd.h> 247 248 #define Fprintf (void)fprintf 249 #define Sprintf (void)sprintf 250 #define Printf (void)printf 251 252 #define HEADERSIZE (sizeof(struct ip) + lsrrlen + sizeof(struct udphdr) + sizeof(struct packetdata)) 253 #define MAX_LSRR ((MAX_IPOPTLEN - 4) / 4) 254 255 /* 256 * Format of the data in a (udp) probe packet. 257 */ 258 struct packetdata { 259 u_char seq; /* sequence number of this packet */ 260 u_char ttl; /* ttl packet left with */ 261 struct timeval tv; /* time packet left */ 262 }; 263 264 struct in_addr gateway[MAX_LSRR + 1]; 265 int lsrrlen = 0; 266 267 u_char packet[512], *outpacket; /* last inbound (icmp) packet */ 268 269 int wait_for_reply __P((int, struct sockaddr_in *)); 270 void send_probe __P((int, int, struct sockaddr_in *)); 271 double deltaT __P((struct timeval *, struct timeval *)); 272 int packet_ok __P((u_char *, int, struct sockaddr_in *, int)); 273 void print __P((u_char *, int, struct sockaddr_in *)); 274 char *inetname __P((struct in_addr)); 275 void usage __P((void)); 276 277 int s; /* receive (icmp) socket file descriptor */ 278 int sndsock; /* send (udp) socket file descriptor */ 279 struct timezone tz; /* leftover */ 280 281 int datalen; /* How much data */ 282 283 char *source = 0; 284 char *hostname; 285 286 int nprobes = 3; 287 int max_ttl = 30; 288 u_short ident; 289 u_short port = 32768+666; /* start udp dest port # for probe packets */ 290 int options; /* socket options */ 291 int verbose; 292 int waittime = 5; /* time to wait for response (in seconds) */ 293 int nflag; /* print addresses numerically */ 294 int dump; 295 296 int 297 main(argc, argv) 298 int argc; 299 char *argv[]; 300 { 301 struct hostent *hp; 302 struct protoent *pe; 303 struct sockaddr_in from, to; 304 int ch, i, lsrr, on, probe, seq, tos, ttl, ttl_flag; 305 struct ip *ip; 306 307 lsrr = 0; 308 on = 1; 309 seq = tos = 0; 310 ttl_flag = 0; 311 while ((ch = getopt(argc, argv, "dDg:lm:np:q:rs:t:w:v")) != -1) 312 switch (ch) { 313 case 'd': 314 options |= SO_DEBUG; 315 break; 316 case 'D': 317 dump = 1; 318 break; 319 case 'g': 320 if (lsrr >= MAX_LSRR) 321 errx(1, "too many gateways; max %d", MAX_LSRR); 322 if (inet_aton(optarg, &gateway[lsrr]) == 0) { 323 hp = gethostbyname(optarg); 324 if (hp == 0) 325 errx(1, "unknown host %s", optarg); 326 memcpy(&gateway[lsrr], hp->h_addr, hp->h_length); 327 } 328 if (++lsrr == 1) 329 lsrrlen = 4; 330 lsrrlen += 4; 331 break; 332 case 'l': 333 ttl_flag = 1; 334 break; 335 case 'm': 336 max_ttl = atoi(optarg); 337 if (max_ttl < 1 || max_ttl > MAXTTL) 338 errx(1, "max ttl must be 1 to %d.", MAXTTL); 339 break; 340 case 'n': 341 nflag++; 342 break; 343 case 'p': 344 port = atoi(optarg); 345 if (port < 1) 346 errx(1, "port must be >0."); 347 break; 348 case 'q': 349 nprobes = atoi(optarg); 350 if (nprobes < 1) 351 errx(1, "nprobes must be >0."); 352 break; 353 case 'r': 354 options |= SO_DONTROUTE; 355 break; 356 case 's': 357 /* 358 * set the ip source address of the outbound 359 * probe (e.g., on a multi-homed host). 360 */ 361 source = optarg; 362 break; 363 case 't': 364 tos = atoi(optarg); 365 if (tos < 0 || tos > 255) 366 errx(1, "tos must be 0 to 255."); 367 break; 368 case 'v': 369 verbose++; 370 break; 371 case 'w': 372 waittime = atoi(optarg); 373 if (waittime <= 1) 374 errx(1, "wait must be >1 sec."); 375 break; 376 default: 377 usage(); 378 } 379 argc -= optind; 380 argv += optind; 381 382 if (argc < 1) 383 usage(); 384 385 setlinebuf (stdout); 386 387 (void) memset(&to, 0, sizeof(struct sockaddr)); 388 to.sin_family = AF_INET; 389 if (inet_aton(*argv, &to.sin_addr) != 0) 390 hostname = *argv; 391 else { 392 hp = gethostbyname(*argv); 393 if (hp == 0) 394 errx(1, "unknown host %s", *argv); 395 to.sin_family = hp->h_addrtype; 396 memcpy(&to.sin_addr, hp->h_addr, hp->h_length); 397 hostname = hp->h_name; 398 } 399 if (*++argv) 400 datalen = atoi(*argv); 401 if (datalen < 0 || datalen > IP_MAXPACKET - HEADERSIZE) 402 errx(1, "packet size must be 0 to %d.", 403 IP_MAXPACKET - HEADERSIZE); 404 datalen += HEADERSIZE; 405 406 outpacket = (u_char *)malloc(datalen); 407 if (outpacket == 0) 408 err(1, "malloc"); 409 (void) memset(outpacket, 0, datalen); 410 411 ip = (struct ip *)outpacket; 412 if (lsrr != 0) { 413 u_char *p; 414 p = (u_char *)(ip + 1); 415 *p++ = IPOPT_NOP; 416 *p++ = IPOPT_LSRR; 417 *p++ = lsrrlen - 1; 418 *p++ = IPOPT_MINOFF; 419 gateway[lsrr] = to.sin_addr; 420 for (i = 1; i <= lsrr; i++) 421 *((struct in_addr *)p)++ = gateway[i]; 422 ip->ip_dst = gateway[0]; 423 } else 424 ip->ip_dst = to.sin_addr; 425 ip->ip_off = 0; 426 ip->ip_hl = (sizeof(struct ip) + lsrrlen) >> 2; 427 ip->ip_p = IPPROTO_UDP; 428 ip->ip_v = IPVERSION; 429 ip->ip_tos = tos; 430 431 ident = (getpid() & 0xffff) | 0x8000; 432 433 if ((pe = getprotobyname("icmp")) == NULL) { 434 Fprintf(stderr, "icmp: unknown protocol\n"); 435 exit(10); 436 } 437 if ((s = socket(AF_INET, SOCK_RAW, pe->p_proto)) < 0) 438 err(5, "icmp socket"); 439 if (options & SO_DEBUG) 440 (void) setsockopt(s, SOL_SOCKET, SO_DEBUG, 441 (char *)&on, sizeof(on)); 442 if (options & SO_DONTROUTE) 443 (void) setsockopt(s, SOL_SOCKET, SO_DONTROUTE, 444 (char *)&on, sizeof(on)); 445 446 if ((sndsock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) 447 err(5, "raw socket"); 448 449 #ifdef SO_SNDBUF 450 if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, (char *)&datalen, 451 sizeof(datalen)) < 0) 452 err(6, "SO_SNDBUF"); 453 #endif SO_SNDBUF 454 #ifdef IP_HDRINCL 455 if (setsockopt(sndsock, IPPROTO_IP, IP_HDRINCL, (char *)&on, 456 sizeof(on)) < 0) 457 err(6, "IP_HDRINCL"); 458 #endif IP_HDRINCL 459 if (options & SO_DEBUG) 460 (void) setsockopt(sndsock, SOL_SOCKET, SO_DEBUG, 461 (char *)&on, sizeof(on)); 462 if (options & SO_DONTROUTE) 463 (void) setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE, 464 (char *)&on, sizeof(on)); 465 466 if (source) { 467 (void) memset(&from, 0, sizeof(struct sockaddr)); 468 from.sin_family = AF_INET; 469 if (inet_aton(source, &from.sin_addr) == 0) 470 errx(1, "unknown host %s", source); 471 ip->ip_src = from.sin_addr; 472 #ifndef IP_HDRINCL 473 if (bind(sndsock, (struct sockaddr *)&from, sizeof(from)) < 0) 474 err(1, "bind"); 475 #endif IP_HDRINCL 476 } 477 478 setuid(getuid()); 479 Fprintf(stderr, "traceroute to %s (%s)", hostname, 480 inet_ntoa(to.sin_addr)); 481 if (source) 482 Fprintf(stderr, " from %s", source); 483 Fprintf(stderr, ", %d hops max, %d byte packets\n", max_ttl, datalen); 484 (void) fflush(stderr); 485 486 for (ttl = 1; ttl <= max_ttl; ++ttl) { 487 u_long lastaddr = 0; 488 int got_there = 0; 489 int unreachable = 0; 490 491 Printf("%2d ", ttl); 492 for (probe = 0; probe < nprobes; ++probe) { 493 int cc; 494 struct timeval t1, t2; 495 struct timezone tz; 496 497 (void) gettimeofday(&t1, &tz); 498 send_probe(++seq, ttl, &to); 499 while (cc = wait_for_reply(s, &from)) { 500 (void) gettimeofday(&t2, &tz); 501 /* 502 * Since we'll be receiving all ICMP 503 * messages to this host above, we may 504 * never end up with cc=0, so we need 505 * an additional termination check. 506 */ 507 if (t2.tv_sec - t1.tv_sec > waittime) { 508 cc = 0; 509 break; 510 } 511 if ((i = packet_ok(packet, cc, &from, seq))) { 512 if (from.sin_addr.s_addr != lastaddr) { 513 print(packet, cc, &from); 514 lastaddr = from.sin_addr.s_addr; 515 } 516 ip = (struct ip *)packet; 517 Printf(" %g ms", deltaT(&t1, &t2)); 518 if (ttl_flag) 519 Printf(" (ttl = %d)", 520 ip->ip_ttl); 521 switch(i - 1) { 522 case ICMP_UNREACH_PORT: 523 #ifndef ARCHAIC 524 ip = (struct ip *)packet; 525 if (ip->ip_ttl <= 1) 526 Printf(" !"); 527 #endif ARCHAIC 528 ++got_there; 529 break; 530 case ICMP_UNREACH_NET: 531 ++unreachable; 532 Printf(" !N"); 533 break; 534 case ICMP_UNREACH_HOST: 535 ++unreachable; 536 Printf(" !H"); 537 break; 538 case ICMP_UNREACH_PROTOCOL: 539 ++got_there; 540 Printf(" !P"); 541 break; 542 case ICMP_UNREACH_NEEDFRAG: 543 ++unreachable; 544 Printf(" !F"); 545 break; 546 case ICMP_UNREACH_SRCFAIL: 547 ++unreachable; 548 Printf(" !S"); 549 break; 550 } 551 break; 552 } 553 } 554 if (cc == 0) 555 Printf(" *"); 556 (void) fflush(stdout); 557 } 558 putchar('\n'); 559 if (got_there || unreachable >= nprobes) 560 exit(0); 561 } 562 } 563 564 int 565 wait_for_reply(sock, from) 566 int sock; 567 struct sockaddr_in *from; 568 { 569 fd_set fds; 570 struct timeval wait; 571 int cc = 0; 572 int fromlen = sizeof (*from); 573 574 FD_ZERO(&fds); 575 FD_SET(sock, &fds); 576 wait.tv_sec = waittime; wait.tv_usec = 0; 577 578 if (select(sock+1, &fds, (fd_set *)0, (fd_set *)0, &wait) > 0) 579 cc=recvfrom(s, (char *)packet, sizeof(packet), 0, 580 (struct sockaddr *)from, &fromlen); 581 582 return(cc); 583 } 584 585 void 586 dump_packet() 587 { 588 u_char *p; 589 int i; 590 591 Fprintf(stderr, "packet data:"); 592 for (p = outpacket, i = 0; i < datalen; i++) { 593 if ((i % 24) == 0) 594 Fprintf(stderr, "\n "); 595 Fprintf(stderr, " %02x", *p++); 596 } 597 Fprintf(stderr, "\n"); 598 } 599 600 void 601 send_probe(seq, ttl, to) 602 int seq, ttl; 603 struct sockaddr_in *to; 604 { 605 struct ip *ip = (struct ip *)outpacket; 606 u_char *p = (u_char *)(ip + 1); 607 struct udphdr *up = (struct udphdr *)(p + lsrrlen); 608 struct packetdata *op = (struct packetdata *)(up + 1); 609 int i; 610 611 ip->ip_len = datalen; 612 ip->ip_ttl = ttl; 613 ip->ip_id = htons(ident+seq); 614 615 up->uh_sport = htons(ident); 616 up->uh_dport = htons(port+seq); 617 up->uh_ulen = htons((u_short)(datalen - sizeof(struct ip) - lsrrlen)); 618 up->uh_sum = 0; 619 620 op->seq = seq; 621 op->ttl = ttl; 622 (void) gettimeofday(&op->tv, &tz); 623 624 if (dump) 625 dump_packet(); 626 627 i = sendto(sndsock, outpacket, datalen, 0, (struct sockaddr *)to, 628 sizeof(struct sockaddr_in)); 629 if (i < 0 || i != datalen) { 630 if (i<0) 631 perror("sendto"); 632 Printf("traceroute: wrote %s %d chars, ret=%d\n", hostname, 633 datalen, i); 634 (void) fflush(stdout); 635 } 636 } 637 638 639 double 640 deltaT(t1p, t2p) 641 struct timeval *t1p, *t2p; 642 { 643 register double dt; 644 645 dt = (double)(t2p->tv_sec - t1p->tv_sec) * 1000.0 + 646 (double)(t2p->tv_usec - t1p->tv_usec) / 1000.0; 647 return (dt); 648 } 649 650 651 /* 652 * Convert an ICMP "type" field to a printable string. 653 */ 654 char * 655 pr_type(t) 656 u_char t; 657 { 658 static char *ttab[] = { 659 "Echo Reply", "ICMP 1", "ICMP 2", "Dest Unreachable", 660 "Source Quench", "Redirect", "ICMP 6", "ICMP 7", 661 "Echo", "ICMP 9", "ICMP 10", "Time Exceeded", 662 "Param Problem", "Timestamp", "Timestamp Reply", "Info Request", 663 "Info Reply" 664 }; 665 666 if(t > 16) 667 return("OUT-OF-RANGE"); 668 669 return(ttab[t]); 670 } 671 672 673 int 674 packet_ok(buf, cc, from, seq) 675 u_char *buf; 676 int cc; 677 struct sockaddr_in *from; 678 int seq; 679 { 680 register struct icmp *icp; 681 u_char type, code; 682 int hlen; 683 #ifndef ARCHAIC 684 struct ip *ip; 685 686 ip = (struct ip *) buf; 687 hlen = ip->ip_hl << 2; 688 if (cc < hlen + ICMP_MINLEN) { 689 if (verbose) 690 Printf("packet too short (%d bytes) from %s\n", cc, 691 inet_ntoa(from->sin_addr)); 692 return (0); 693 } 694 cc -= hlen; 695 icp = (struct icmp *)(buf + hlen); 696 #else 697 icp = (struct icmp *)buf; 698 #endif ARCHAIC 699 type = icp->icmp_type; code = icp->icmp_code; 700 if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS) || 701 type == ICMP_UNREACH) { 702 struct ip *hip; 703 struct udphdr *up; 704 705 hip = &icp->icmp_ip; 706 hlen = hip->ip_hl << 2; 707 up = (struct udphdr *)((u_char *)hip + hlen); 708 if (hlen + 12 <= cc && hip->ip_p == IPPROTO_UDP && 709 up->uh_sport == htons(ident) && 710 up->uh_dport == htons(port+seq)) 711 return (type == ICMP_TIMXCEED? -1 : code+1); 712 } 713 #ifndef ARCHAIC 714 if (verbose) { 715 int i; 716 u_long *lp = (u_long *)&icp->icmp_ip; 717 718 Printf("\n%d bytes from %s", cc, inet_ntoa(from->sin_addr)); 719 Printf(" to %s", inet_ntoa(ip->ip_dst)); 720 Printf(": icmp type %d (%s) code %d\n", type, pr_type(type), 721 icp->icmp_code); 722 for (i = 4; i < cc ; i += sizeof(long)) 723 Printf("%2d: x%8.8lx\n", i, *lp++); 724 } 725 #endif ARCHAIC 726 return(0); 727 } 728 729 730 void 731 print(buf, cc, from) 732 u_char *buf; 733 int cc; 734 struct sockaddr_in *from; 735 { 736 struct ip *ip; 737 int hlen; 738 739 ip = (struct ip *) buf; 740 hlen = ip->ip_hl << 2; 741 cc -= hlen; 742 743 if (nflag) 744 Printf(" %s", inet_ntoa(from->sin_addr)); 745 else 746 Printf(" %s (%s)", inetname(from->sin_addr), 747 inet_ntoa(from->sin_addr)); 748 749 if (verbose) 750 Printf (" %d bytes to %s", cc, inet_ntoa (ip->ip_dst)); 751 } 752 753 754 #ifdef notyet 755 /* 756 * Checksum routine for Internet Protocol family headers (C Version) 757 */ 758 u_short 759 in_cksum(addr, len) 760 u_short *addr; 761 int len; 762 { 763 register int nleft = len; 764 register u_short *w = addr; 765 register u_short answer; 766 register int sum = 0; 767 768 /* 769 * Our algorithm is simple, using a 32 bit accumulator (sum), 770 * we add sequential 16 bit words to it, and at the end, fold 771 * back all the carry bits from the top 16 bits into the lower 772 * 16 bits. 773 */ 774 while (nleft > 1) { 775 sum += *w++; 776 nleft -= 2; 777 } 778 779 /* mop up an odd byte, if necessary */ 780 if (nleft == 1) 781 sum += *(u_char *)w; 782 783 /* 784 * add back carry outs from top 16 bits to low 16 bits 785 */ 786 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ 787 sum += (sum >> 16); /* add carry */ 788 answer = ~sum; /* truncate to 16 bits */ 789 return (answer); 790 } 791 #endif notyet 792 793 /* 794 * Construct an Internet address representation. 795 * If the nflag has been supplied, give 796 * numeric value, otherwise try for symbolic name. 797 */ 798 char * 799 inetname(in) 800 struct in_addr in; 801 { 802 register char *cp; 803 static char line[50]; 804 struct hostent *hp; 805 static char domain[MAXHOSTNAMELEN + 1]; 806 static int first = 1; 807 808 if (first && !nflag) { 809 first = 0; 810 if (gethostname(domain, MAXHOSTNAMELEN) == 0 && 811 (cp = index(domain, '.'))) { 812 (void) strncpy(domain, cp + 1, sizeof(domain)); 813 domain[sizeof(domain) - 1] = '\0'; 814 } else 815 domain[0] = 0; 816 } 817 cp = 0; 818 if (!nflag && in.s_addr != INADDR_ANY) { 819 hp = gethostbyaddr((char *)&in, sizeof (in), AF_INET); 820 if (hp) { 821 if ((cp = index(hp->h_name, '.')) && 822 !strcmp(cp + 1, domain)) 823 *cp = 0; 824 cp = hp->h_name; 825 } 826 } 827 if (cp) { 828 (void) strncpy(line, cp, sizeof(line)); 829 line[sizeof(line) - 1] = '\0'; 830 } else { 831 in.s_addr = ntohl(in.s_addr); 832 #define C(x) ((x) & 0xff) 833 Sprintf(line, "%lu.%lu.%lu.%lu", C(in.s_addr >> 24), 834 C(in.s_addr >> 16), C(in.s_addr >> 8), C(in.s_addr)); 835 } 836 return (line); 837 } 838 839 void 840 usage() 841 { 842 (void)fprintf(stderr, 843 "usage: traceroute [-dDnrv] [-g gateway_addr] ... [-m max_ttl] [-p port#]\n\t\ 844 [-q nqueries] [-s src_addr] [-t tos] [-w wait] host [data size]\n"); 845 exit(1); 846 } 847
Indexes created Sun Sep 28 16:09:52 GMT 2025