1 /* $OpenBSD: traceroute.c,v 1.61 2004/01/26 18:23:51 deraadt Exp $ */
2 /* $NetBSD: traceroute.c,v 1.10 1995/05/21 15:50:45 mycroft Exp $ */
5 * Copyright (c) 1990, 1993
6 * The Regents of the University of California. All rights reserved.
8 * This code is derived from software contributed to Berkeley by
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * @(#)traceroute.c 8.1 (Berkeley) 6/6/93
39 * traceroute host - trace the route ip packets follow going to "host".
41 * Attempt to trace the route an ip packet would follow to some
42 * internet host. We find out intermediate hops by launching probe
43 * packets with a small ttl (time to live) then listening for an
44 * icmp "time exceeded" reply from a gateway. We start our probes
45 * with a ttl of one and increase by one until we get an icmp "port
46 * unreachable" (which means we got to "host") or hit a max (which
47 * defaults to 64 hops & can be changed with the -m flag). Three
48 * probes (change with -q flag) are sent at each ttl setting and a
49 * line is printed showing the ttl, address of the gateway and
50 * round trip time of each probe. If the probe answers come from
51 * different gateways, the address of each responding system will
52 * be printed. If there is no response within a 5 sec. timeout
53 * interval (changed with the -w flag), a "*" is printed for that
56 * Probe packets are UDP format. We don't want the destination
57 * host to process them so the destination port is set to an
58 * unlikely value (if some clod on the destination is using that
59 * value, it can be changed with the -p flag).
61 * A sample use might be:
63 * [yak 71]% traceroute nis.nsf.net.
64 * traceroute to nis.nsf.net (35.1.1.48), 64 hops max, 56 byte packet
65 * 1 helios.ee.lbl.gov (128.3.112.1) 19 ms 19 ms 0 ms
66 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
67 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
68 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 39 ms
69 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 39 ms 39 ms 39 ms
70 * 6 128.32.197.4 (128.32.197.4) 40 ms 59 ms 59 ms
71 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 59 ms
72 * 8 129.140.70.13 (129.140.70.13) 99 ms 99 ms 80 ms
73 * 9 129.140.71.6 (129.140.71.6) 139 ms 239 ms 319 ms
74 * 10 129.140.81.7 (129.140.81.7) 220 ms 199 ms 199 ms
75 * 11 nic.merit.edu (35.1.1.48) 239 ms 239 ms 239 ms
77 * Note that lines 2 & 3 are the same. This is due to a buggy
78 * kernel on the 2nd hop system -- lbl-csam.arpa -- that forwards
79 * packets with a zero ttl.
81 * A more interesting example is:
83 * [yak 72]% traceroute allspice.lcs.mit.edu.
84 * traceroute to allspice.lcs.mit.edu (18.26.0.115), 64 hops max
85 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
86 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms
87 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms
88 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms
89 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms
90 * 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms
91 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms
92 * 8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms
93 * 9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms
94 * 10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms
95 * 11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms
97 * 13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms
102 * 18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms
104 * (I start to see why I'm having so much trouble with mail to
105 * MIT.) Note that the gateways 12, 14, 15, 16 & 17 hops away
106 * either don't send ICMP "time exceeded" messages or send them
107 * with a ttl too small to reach us. 14 - 17 are running the
108 * MIT C Gateway code that doesn't send "time exceeded"s. God
109 * only knows what's going on with 12.
111 * The silent gateway 12 in the above may be the result of a bug in
112 * the 4.[23]BSD network code (and its derivatives): 4.x (x <= 3)
113 * sends an unreachable message using whatever ttl remains in the
114 * original datagram. Since, for gateways, the remaining ttl is
115 * zero, the icmp "time exceeded" is guaranteed to not make it back
116 * to us. The behavior of this bug is slightly more interesting
117 * when it appears on the destination system:
119 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
120 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 39 ms
121 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 39 ms 19 ms
122 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 19 ms
123 * 5 ccn-nerif35.Berkeley.EDU (128.32.168.35) 39 ms 39 ms 39 ms
124 * 6 csgw.Berkeley.EDU (128.32.133.254) 39 ms 59 ms 39 ms
131 * 13 rip.Berkeley.EDU (128.32.131.22) 59 ms ! 39 ms ! 39 ms !
133 * Notice that there are 12 "gateways" (13 is the final
134 * destination) and exactly the last half of them are "missing".
135 * What's really happening is that rip (a Sun-3 running Sun OS3.5)
136 * is using the ttl from our arriving datagram as the ttl in its
137 * icmp reply. So, the reply will time out on the return path
138 * (with no notice sent to anyone since icmp's aren't sent for
139 * icmp's) until we probe with a ttl that's at least twice the path
140 * length. I.e., rip is really only 7 hops away. A reply that
141 * returns with a ttl of 1 is a clue this problem exists.
142 * Traceroute prints a "!" after the time if the ttl is <= 1.
143 * Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or
144 * non-standard (HPUX) software, expect to see this problem
145 * frequently and/or take care picking the target host of your
148 * Other possible annotations after the time are !H, !N, !P (got a host,
149 * network or protocol unreachable, respectively), !S or !F (source
150 * route failed or fragmentation needed -- neither of these should
151 * ever occur and the associated gateway is busted if you see one). If
152 * almost all the probes result in some kind of unreachable, traceroute
153 * will give up and exit.
157 * This program must be run by root or be setuid. (I suggest that
158 * you *don't* make it setuid -- casual use could result in a lot
159 * of unnecessary traffic on our poor, congested nets.)
161 * This program requires a kernel mod that does not appear in any
162 * system available from Berkeley: A raw ip socket using proto
163 * IPPROTO_RAW must interpret the data sent as an ip datagram (as
164 * opposed to data to be wrapped in a ip datagram). See the README
165 * file that came with the source to this program for a description
166 * of the mods I made to /sys/netinet/raw_ip.c. Your mileage may
167 * vary. But, again, ANY 4.x (x < 4) BSD KERNEL WILL HAVE TO BE
168 * MODIFIED TO RUN THIS PROGRAM.
170 * The udp port usage may appear bizarre (well, ok, it is bizarre).
171 * The problem is that an icmp message only contains 8 bytes of
172 * data from the original datagram. 8 bytes is the size of a udp
173 * header so, if we want to associate replies with the original
174 * datagram, the necessary information must be encoded into the
175 * udp header (the ip id could be used but there's no way to
176 * interlock with the kernel's assignment of ip id's and, anyway,
177 * it would have taken a lot more kernel hacking to allow this
178 * code to set the ip id). So, to allow two or more users to
179 * use traceroute simultaneously, we use this task's pid as the
180 * source port (the high bit is set to move the port number out
181 * of the "likely" range). To keep track of which probe is being
182 * replied to (so times and/or hop counts don't get confused by a
183 * reply that was delayed in transit), we increment the destination
184 * port number before each probe.
186 * Don't use this as a coding example. I was trying to find a
187 * routing problem and this code sort-of popped out after 48 hours
188 * without sleep. I was amazed it ever compiled, much less ran.
190 * I stole the idea for this program from Steve Deering. Since
191 * the first release, I've learned that had I attended the right
192 * IETF working group meetings, I also could have stolen it from Guy
193 * Almes or Matt Mathis. I don't know (or care) who came up with
194 * the idea first. I envy the originators' perspicacity and I'm
195 * glad they didn't keep the idea a secret.
197 * Tim Seaver, Ken Adelman and C. Philip Wood provided bug fixes and/or
198 * enhancements to the original distribution.
200 * I've hacked up a round-trip-route version of this that works by
201 * sending a loose-source-routed udp datagram through the destination
202 * back to yourself. Unfortunately, SO many gateways botch source
203 * routing, the thing is almost worthless. Maybe one day...
205 * -- Van Jacobson (van@helios.ee.lbl.gov)
206 * Tue Dec 20 03:50:13 PST 1988
209 #include <sys/param.h>
210 #include <sys/time.h>
211 #include <sys/socket.h>
212 #include <sys/file.h>
213 #include <sys/ioctl.h>
214 #include <sys/sysctl.h>
216 #include <netinet/in_systm.h>
217 #include <netinet/in.h>
218 #include <netinet/ip.h>
219 #include <netinet/ip_icmp.h>
220 #include <netinet/ip_var.h>
221 #include <netinet/udp.h>
223 #include <arpa/inet.h>
234 #define MAX_LSRR ((MAX_IPOPTLEN - 4) / 4)
237 * Format of the data in a (udp) probe packet.
240 u_char seq; /* sequence number of this packet */
241 u_int8_t ttl; /* ttl packet left with */
242 u_int32_t sec; /* time packet left */
247 * Support for ICMP extensions - RFC4950.
249 #define ICMP_EXT_OFFSET 8 + 128 /* ICMP type, code, checksum (unused)
250 * + original datagram */
251 #define ICMP_EXT_VERSION 2
253 /* ICMP Extension Header according to RFC4884. */
254 #define EXT_VERSION(x) (((x) & 0xf0000000) >> 28)
255 #define EXT_CHECKSUM(x) ((x) & 0x0000ffff)
258 * ICMP extensions, object header
260 struct icmp_ext_obj_hdr {
263 #define MPLS_STACK_ENTRY_CLASS 1
265 #define MPLS_STACK_ENTRY_C_TYPE 1
268 /* MPLS Label Stack Object. */
269 #define MPLS_LABEL(x) (((x) & 0xfffff000) >> 12)
270 #define MPLS_EXP(x) (((x) & 0x00000e00) >> 9)
271 #define MPLS_STACK(x) (((x) & 0x00000100) >> 8)
272 #define MPLS_TTL(x) ((x) & 0x000000ff)
274 struct in_addr gateway[MAX_LSRR + 1];
277 int32_t usec_perturb;
279 u_char packet[512], *outpacket; /* last inbound (icmp) packet */
281 void decode_extensions(unsigned char *, int);
282 void dump_packet(void);
283 int wait_for_reply(int, struct sockaddr_in *, struct timeval *);
284 void send_probe(int, u_int8_t, int, struct sockaddr_in *);
285 int packet_ok(u_char *, int, struct sockaddr_in *, int, int);
286 const char *pr_type(u_int8_t);
287 void print(u_char *, int, struct sockaddr_in *);
288 char *inetname(struct in_addr);
289 u_short in_cksum(u_short *, int);
292 int s; /* receive (icmp) socket file descriptor */
293 int sndsock; /* send (udp) socket file descriptor */
295 int datalen; /* How much data */
296 int headerlen; /* How long packet's header is */
302 u_int8_t max_ttl = IPDEFTTL;
303 u_int8_t first_ttl = 1;
305 u_short port = 32768+666; /* start udp dest port # for probe packets */
306 u_char proto = IPPROTO_UDP;
307 u_int8_t icmp_type = ICMP_ECHO; /* default ICMP code/type */
308 u_char icmp_code = 0;
309 int options; /* socket options */
311 int waittime = 5; /* time to wait for response (in seconds) */
312 int nflag; /* print addresses numerically */
314 int Mflag; /* show MPLS labels if any */
317 main(int argc, char *argv[])
319 int mib[4] = { CTL_NET, PF_INET, IPPROTO_IP, IPCTL_DEFTTL };
320 int ttl_flag = 0, incflag = 1, protoset = 0, sump = 0;
321 int ch, i, lsrr = 0, on = 1, probe, seq = 0, tos = 0;
322 size_t size = sizeof(max_ttl);
323 struct sockaddr_in from, to;
331 if ((s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0)
332 err(5, "icmp socket");
333 if ((sndsock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
334 err(5, "raw socket");
340 sysctl(mib, sizeof(mib)/sizeof(mib[0]), &max_ttl, &size, NULL, 0);
342 while ((ch = getopt(argc, argv, "SDIdg:f:m:np:q:rs:t:w:vlP:cM")) != -1)
350 l = strtol(optarg, &ep, 10);
351 if (errno || !*optarg || *ep || l < 1 || l > max_ttl)
352 errx(1, "min ttl must be 1 to %u.", max_ttl);
353 first_ttl = (u_int8_t)l;
365 if (lsrr >= MAX_LSRR)
366 errx(1, "too many gateways; max %d", MAX_LSRR);
367 if (inet_aton(optarg, &gateway[lsrr]) == 0) {
368 hp = gethostbyname(optarg);
370 errx(1, "unknown host %s", optarg);
371 memcpy(&gateway[lsrr], hp->h_addr, hp->h_length);
379 errx(1, "protocol already set with -P");
381 proto = IPPROTO_ICMP;
389 l = strtol(optarg, &ep, 10);
390 if (errno || !*optarg || *ep || l < first_ttl ||
392 errx(1, "max ttl must be %u to %u.", first_ttl,
394 max_ttl = (u_int8_t)l;
405 l = strtol(optarg, &ep, 10);
406 if (errno || !*optarg || *ep || l <= 0 || l >= 65536)
407 errx(1, "port must be >0, <65536.");
412 errx(1, "protocol already set with -I");
416 l = strtol(optarg, &ep, 10);
417 if (errno || !*optarg || *ep || l < 1 ||
419 struct protoent *pent;
421 pent = getprotobyname(optarg);
423 proto = pent->p_proto;
425 errx(1, "proto must be >=1, or a name.");
432 l = strtol(optarg, &ep, 10);
433 if (errno || !*optarg || *ep || l < 1 || l > INT_MAX)
434 errx(1, "nprobes must be >0.");
438 options |= SO_DONTROUTE;
442 * set the ip source address of the outbound
443 * probe (e.g., on a multi-homed host).
450 l = strtol(optarg, &ep, 10);
451 if (errno || !*optarg || *ep || l < 0 || l > 255)
452 errx(1, "tos must be 0 to 255.");
461 l = strtol(optarg, &ep, 10);
462 if (errno || !*optarg || *ep || l <= 1 || l > INT_MAX)
463 errx(1, "wait must be >1 sec.");
477 memset(&to, 0, sizeof(struct sockaddr));
478 to.sin_family = AF_INET;
479 if (inet_aton(*argv, &to.sin_addr) != 0)
482 hp = gethostbyname(*argv);
484 errx(1, "unknown host %s", *argv);
485 to.sin_family = hp->h_addrtype;
486 memcpy(&to.sin_addr, hp->h_addr, hp->h_length);
487 if ((hostname = strdup(hp->h_name)) == NULL)
489 if (hp->h_addr_list[1] != NULL)
490 warnx("Warning: %s has multiple addresses; using %s",
491 hostname, inet_ntoa(to.sin_addr));
496 l = strtol(*argv, &ep, 10);
497 if (errno || !*argv || *ep || l < 0 || l > INT_MAX)
498 errx(1, "datalen out of range");
504 headerlen = (sizeof(struct ip) + lsrrlen +
505 sizeof(struct udphdr) + sizeof(struct packetdata));
508 headerlen = (sizeof(struct ip) + lsrrlen +
509 sizeof(struct icmp) + sizeof(struct packetdata));
512 headerlen = (sizeof(struct ip) + lsrrlen +
513 sizeof(struct packetdata));
516 if (datalen < 0 || datalen > IP_MAXPACKET - headerlen)
517 errx(1, "packet size must be 0 to %d.",
518 IP_MAXPACKET - headerlen);
520 datalen += headerlen;
522 outpacket = (u_char *)malloc(datalen);
523 if (outpacket == NULL)
525 memset(outpacket, 0, datalen);
527 ip = (struct ip *)outpacket;
529 u_char *p = (u_char *)(ip + 1);
535 gateway[lsrr] = to.sin_addr;
536 for (i = 1; i <= lsrr; i++) {
537 memcpy(p, &gateway[i], sizeof(struct in_addr));
538 p += sizeof(struct in_addr);
540 ip->ip_dst = gateway[0];
542 ip->ip_dst = to.sin_addr;
543 ip->ip_off = htons(0);
544 ip->ip_hl = (sizeof(struct ip) + lsrrlen) >> 2;
546 ip->ip_v = IPVERSION;
549 ident = (getpid() & 0xffff) | 0x8000;
550 tmprnd = arc4random();
551 sec_perturb = (tmprnd & 0x80000000) ? -(tmprnd & 0x7ff) :
553 usec_perturb = arc4random();
555 if (options & SO_DEBUG)
556 setsockopt(s, SOL_SOCKET, SO_DEBUG, (char *)&on, sizeof(on));
558 if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, (char *)&datalen,
559 sizeof(datalen)) < 0)
561 #endif /* SO_SNDBUF */
563 if (setsockopt(sndsock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
565 err(6, "IP_HDRINCL");
566 #endif /* IP_HDRINCL */
567 if (options & SO_DEBUG)
568 setsockopt(sndsock, SOL_SOCKET, SO_DEBUG,
569 (char *)&on, sizeof(on));
570 if (options & SO_DONTROUTE)
571 setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE,
572 (char *)&on, sizeof(on));
575 memset(&from, 0, sizeof(struct sockaddr));
576 from.sin_family = AF_INET;
577 if (inet_aton(source, &from.sin_addr) == 0)
578 errx(1, "unknown host %s", source);
579 ip->ip_src = from.sin_addr;
581 (ntohl(from.sin_addr.s_addr) & 0xff000000U) == 0x7f000000U &&
582 (ntohl(to.sin_addr.s_addr) & 0xff000000U) != 0x7f000000U)
583 errx(1, "source is on 127/8, destination is not");
586 bind(sndsock, (struct sockaddr *)&from, sizeof(from)) < 0)
590 fprintf(stderr, "traceroute to %s (%s)", hostname,
591 inet_ntoa(to.sin_addr));
593 fprintf(stderr, " from %s", source);
594 fprintf(stderr, ", %u hops max, %d byte packets\n", max_ttl, datalen);
598 printf("Skipping %u intermediate hops\n", first_ttl - 1);
600 for (ttl = first_ttl; ttl <= max_ttl; ++ttl) {
601 int got_there = 0, unreachable = 0, timeout = 0, loss;
603 in_addr_t lastaddr = 0;
607 for (probe = 0, loss = 0; probe < nprobes; ++probe) {
609 struct timeval t1, t2;
612 gettimeofday(&t1, NULL);
613 send_probe(++seq, ttl, incflag, &to);
614 while ((cc = wait_for_reply(s, &from, &t1))) {
615 gettimeofday(&t2, NULL);
616 if (t2.tv_sec - t1.tv_sec > waittime) {
620 i = packet_ok(packet, cc, &from, seq, incflag);
621 /* Skip short packet */
625 from.sin_addr.s_addr != lastaddr) {
628 print(packet, cc, &from);
629 lastaddr = from.sin_addr.s_addr;
632 dt = (quad_t)(t2.tv_sec - t1.tv_sec) * 1000000 +
633 (quad_t)(t2.tv_usec - t1.tv_usec);
634 printf(" %u", (u_int)(dt / 1000));
636 printf(".%u", (u_int)(dt % 1000));
638 ip = (struct ip *)packet;
640 printf(" (%u)", ip->ip_ttl);
643 ip = (struct ip *)packet;
650 /* time exceeded in transit */
655 case ICMP_UNREACH_PORT:
657 ip = (struct ip *)packet;
663 case ICMP_UNREACH_NET:
667 case ICMP_UNREACH_HOST:
671 case ICMP_UNREACH_PROTOCOL:
675 case ICMP_UNREACH_NEEDFRAG:
679 case ICMP_UNREACH_SRCFAIL:
683 case ICMP_UNREACH_FILTER_PROHIB:
687 case ICMP_UNREACH_NET_PROHIB: /*misuse*/
691 case ICMP_UNREACH_HOST_PROHIB:
695 case ICMP_UNREACH_NET_UNKNOWN:
696 case ICMP_UNREACH_HOST_UNKNOWN:
700 case ICMP_UNREACH_ISOLATED:
704 case ICMP_UNREACH_TOSNET:
705 case ICMP_UNREACH_TOSHOST:
711 printf(" !<%d>", i - 1);
721 else if (cc && probe == nprobes - 1 && Mflag)
722 decode_extensions(packet, cc);
726 printf(" (%d%% loss)", (loss * 100) / nprobes);
728 if (got_there || (unreachable && (unreachable + timeout) >= nprobes))
735 wait_for_reply(int sock, struct sockaddr_in *from, struct timeval *sent)
737 socklen_t fromlen = sizeof (*from);
738 struct timeval now, wait;
742 fdsn = howmany(sock+1, NFDBITS) * sizeof(fd_mask);
743 if ((fdsp = (fd_set *)malloc(fdsn)) == NULL)
745 memset(fdsp, 0, fdsn);
747 gettimeofday(&now, NULL);
748 wait.tv_sec = (sent->tv_sec + waittime) - now.tv_sec;
749 wait.tv_usec = sent->tv_usec - now.tv_usec;
750 if (wait.tv_usec < 0) {
751 wait.tv_usec += 1000000;
755 wait.tv_sec = wait.tv_usec = 0;
757 if (select(sock+1, fdsp, NULL, NULL, &wait) > 0)
758 cc = recvfrom(s, (char *)packet, sizeof(packet), 0,
759 (struct sockaddr *)from, &fromlen);
766 decode_extensions(unsigned char *buf, int ip_len)
769 struct icmp_ext_obj_hdr *obj_hdr;
771 int data_len, obj_len;
774 ip = (struct ip *)buf;
776 if (ip_len <= (int)(sizeof(struct ip) + ICMP_EXT_OFFSET)) {
778 * No support for ICMP extensions on this host
784 * Move forward to the start of the ICMP extensions, if present
786 buf += (ip->ip_hl << 2) + ICMP_EXT_OFFSET;
787 cmn_hdr = (uint32_t *)buf;
789 if (EXT_VERSION(ntohl(*cmn_hdr)) != ICMP_EXT_VERSION) {
796 data_len = ip_len - ((u_char *)cmn_hdr - (u_char *)ip);
799 * Check the checksum, cmn_hdr->checksum == 0 means no checksum'ing
802 * If the checksum is ok, we'll get 0, as the checksum is calculated
803 * with the checksum field being 0'd.
805 if (EXT_CHECKSUM(ntohl(*cmn_hdr)) &&
806 in_cksum((u_short *)cmn_hdr, data_len)) {
810 buf += sizeof(*cmn_hdr);
811 data_len -= sizeof(*cmn_hdr);
813 while (data_len >= (int)sizeof(struct icmp_ext_obj_hdr)) {
814 unsigned char *nextbuf;
816 obj_hdr = (struct icmp_ext_obj_hdr *)buf;
817 obj_len = ntohs(obj_hdr->length);
820 * Sanity check the length field
822 if (obj_len < (int)sizeof(*obj_hdr) || obj_len > data_len)
825 /* Object has to be 4-byte aligned. */
829 nextbuf = buf + obj_len;
833 * Move past the object header
835 buf += sizeof(struct icmp_ext_obj_hdr);
836 obj_len -= sizeof(struct icmp_ext_obj_hdr);
838 switch (obj_hdr->class_num) {
839 case MPLS_STACK_ENTRY_CLASS:
840 switch (obj_hdr->c_type) {
841 case MPLS_STACK_ENTRY_C_TYPE:
842 while (obj_len >= (int)sizeof(uint32_t)) {
843 mpls_hdr = ntohl(*(uint32_t *)buf);
845 buf += sizeof(uint32_t);
846 obj_len -= sizeof(uint32_t);
847 printf(" [MPLS: Label %d Exp %d]",
848 MPLS_LABEL(mpls_hdr),
853 * Something went wrong, and we're at
854 * a unknown offset into the packet,
855 * ditch the rest of it.
862 * Unknown object, skip past it
871 * Unknown object, skip past it
885 fprintf(stderr, "packet data:");
886 for (p = outpacket, i = 0; i < datalen; i++) {
888 fprintf(stderr, "\n ");
889 fprintf(stderr, " %02x", *p++);
891 fprintf(stderr, "\n");
895 send_probe(int seq, u_int8_t ttl, int iflag, struct sockaddr_in *to)
897 struct ip *ip = (struct ip *)outpacket;
898 u_char *p = (u_char *)(ip + 1);
899 struct udphdr *up = (struct udphdr *)(p + lsrrlen);
900 struct icmp *icmpp = (struct icmp *)(p + lsrrlen);
901 struct packetdata *op;
905 ip->ip_len = datalen;
907 ip->ip_id = htons(ident+seq);
911 icmpp->icmp_type = icmp_type;
912 icmpp->icmp_code = icmp_code;
913 icmpp->icmp_seq = htons(seq);
914 icmpp->icmp_id = htons(ident);
915 op = (struct packetdata *)(icmpp + 1);
918 up->uh_sport = htons(ident);
920 up->uh_dport = htons(port+seq);
922 up->uh_dport = htons(port);
923 up->uh_ulen = htons((u_short)(datalen - sizeof(struct ip) -
926 op = (struct packetdata *)(up + 1);
929 op = (struct packetdata *)(ip + 1);
936 * We don't want hostiles snooping the net to get any useful
937 * information about us. Send the timestamp in network byte order,
938 * and perturb the timestamp enough that they won't know our
939 * real clock ticker. We don't want to perturb the time by too
940 * much: being off by a suspiciously large amount might indicate
943 * The timestamps in the packet are currently unused. If future
944 * work wants to use them they will have to subtract out the
945 * perturbation first.
947 gettimeofday(&tv, NULL);
948 op->sec = htonl(tv.tv_sec + sec_perturb);
949 op->usec = htonl((tv.tv_usec + usec_perturb) % 1000000);
951 if (proto == IPPROTO_ICMP && icmp_type == ICMP_ECHO) {
952 icmpp->icmp_cksum = 0;
953 icmpp->icmp_cksum = in_cksum((u_short *)icmpp,
954 datalen - sizeof(struct ip) - lsrrlen);
955 if (icmpp->icmp_cksum == 0)
956 icmpp->icmp_cksum = 0xffff;
962 i = sendto(sndsock, outpacket, datalen, 0, (struct sockaddr *)to,
963 sizeof(struct sockaddr_in));
964 if (i < 0 || i != datalen) {
967 printf("traceroute: wrote %s %d chars, ret=%d\n", hostname,
973 static const char *ttab[] = {
996 * Convert an ICMP "type" field to a printable string.
1002 return ("OUT-OF-RANGE");
1007 packet_ok(u_char *buf, int cc, struct sockaddr_in *from, int seq, int iflag)
1016 ip = (struct ip *) buf;
1017 hlen = ip->ip_hl << 2;
1018 if (cc < hlen + ICMP_MINLEN) {
1020 printf("packet too short (%d bytes) from %s\n", cc,
1021 inet_ntoa(from->sin_addr));
1025 icp = (struct icmp *)(buf + hlen);
1027 icp = (struct icmp *)buf;
1028 #endif /* ARCHAIC */
1029 type = icp->icmp_type;
1030 code = icp->icmp_code;
1031 if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS) ||
1032 type == ICMP_UNREACH || type == ICMP_ECHOREPLY) {
1037 hip = &icp->icmp_ip;
1038 hlen = hip->ip_hl << 2;
1042 if (icmp_type == ICMP_ECHO &&
1043 type == ICMP_ECHOREPLY &&
1044 icp->icmp_id == htons(ident) &&
1045 icp->icmp_seq == htons(seq))
1046 return (-2); /* we got there */
1048 icmpp = (struct icmp *)((u_char *)hip + hlen);
1049 if (hlen + 8 <= cc && hip->ip_p == IPPROTO_ICMP &&
1050 icmpp->icmp_id == htons(ident) &&
1051 icmpp->icmp_seq == htons(seq))
1052 return (type == ICMP_TIMXCEED? -1 : code + 1);
1056 up = (struct udphdr *)((u_char *)hip + hlen);
1057 if (hlen + 12 <= cc && hip->ip_p == proto &&
1058 up->uh_sport == htons(ident) &&
1059 ((iflag && up->uh_dport == htons(port + seq)) ||
1060 (!iflag && up->uh_dport == htons(port))))
1061 return (type == ICMP_TIMXCEED? -1 : code + 1);
1064 /* this is some odd, user specified proto,
1065 * how do we check it?
1067 if (hip->ip_p == proto)
1068 return (type == ICMP_TIMXCEED? -1 : code + 1);
1074 in_addr_t *lp = (in_addr_t *)&icp->icmp_ip;
1076 printf("\n%d bytes from %s", cc, inet_ntoa(from->sin_addr));
1077 printf(" to %s", inet_ntoa(ip->ip_dst));
1078 printf(": icmp type %u (%s) code %d\n", type, pr_type(type),
1080 for (i = 4; i < cc ; i += sizeof(in_addr_t))
1081 printf("%2d: x%8.8lx\n", i, (unsigned long)*lp++);
1083 #endif /* ARCHAIC */
1088 print(u_char *buf, int cc, struct sockaddr_in *from)
1093 ip = (struct ip *) buf;
1094 hlen = ip->ip_hl << 2;
1098 printf(" %s", inet_ntoa(from->sin_addr));
1100 printf(" %s (%s)", inetname(from->sin_addr),
1101 inet_ntoa(from->sin_addr));
1104 printf(" %d bytes to %s", cc, inet_ntoa (ip->ip_dst));
1109 * Checksum routine for Internet Protocol family headers (C Version)
1112 in_cksum(u_short *addr, int len)
1114 u_short *w = addr, answer;
1115 int nleft = len, sum = 0;
1118 * Our algorithm is simple, using a 32 bit accumulator (sum),
1119 * we add sequential 16 bit words to it, and at the end, fold
1120 * back all the carry bits from the top 16 bits into the lower
1128 /* mop up an odd byte, if necessary */
1130 sum += *(u_char *)w;
1133 * add back carry outs from top 16 bits to low 16 bits
1135 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
1136 sum += (sum >> 16); /* add carry */
1137 answer = ~sum; /* truncate to 16 bits */
1142 * Construct an Internet address representation.
1143 * If the nflag has been supplied, give
1144 * numeric value, otherwise try for symbolic name.
1147 inetname(struct in_addr in)
1149 static char domain[MAXHOSTNAMELEN], line[MAXHOSTNAMELEN];
1150 static int first = 1;
1154 if (first && !nflag) {
1156 if (gethostname(domain, sizeof domain) == 0 &&
1157 (cp = strchr(domain, '.')) != NULL) {
1158 strlcpy(domain, cp + 1, sizeof(domain));
1161 if (!nflag && in.s_addr != INADDR_ANY) {
1162 hp = gethostbyaddr(&in, sizeof(in), AF_INET);
1164 if ((cp = strchr(hp->h_name, '.')) != NULL &&
1165 strcmp(cp + 1, domain) == 0)
1167 strlcpy(line, hp->h_name, sizeof(line));
1171 return (inet_ntoa(in));
1178 "usage: %s [-cdDIlMnrSv] [-f first_ttl] [-g gateway_addr] [-m max_ttl]\n"
1179 "\t[-p port] [-P proto] [-q nqueries] [-s src_addr] [-t tos]\n"
1180 "\t[-w waittime] host [packetsize]\n", getprogname());