2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 static char copyright[] =
39 "@(#) Copyright (c) 1990, 1993\n\
40 The Regents of the University of California. All rights reserved.\n";
44 static char sccsid[] = "@(#)traceroute.c 8.1 (Berkeley) 6/6/93";
48 * traceroute host - trace the route ip packets follow going to "host".
50 * Attempt to trace the route an ip packet would follow to some
51 * internet host. We find out intermediate hops by launching probe
52 * packets with a small ttl (time to live) then listening for an
53 * icmp "time exceeded" reply from a gateway. We start our probes
54 * with a ttl of one and increase by one until we get an icmp "port
55 * unreachable" (which means we got to "host") or hit a max (which
56 * defaults to 30 hops & can be changed with the -m flag). Three
57 * probes (change with -q flag) are sent at each ttl setting and a
58 * line is printed showing the ttl, address of the gateway and
59 * round trip time of each probe. If the probe answers come from
60 * different gateways, the address of each responding system will
61 * be printed. If there is no response within a 5 sec. timeout
62 * interval (changed with the -w flag), a "*" is printed for that
65 * Probe packets are UDP format. We don't want the destination
66 * host to process them so the destination port is set to an
67 * unlikely value (if some clod on the destination is using that
68 * value, it can be changed with the -p flag).
70 * A sample use might be:
72 * [yak 71]% traceroute nis.nsf.net.
73 * traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 56 byte packet
74 * 1 helios.ee.lbl.gov (128.3.112.1) 19 ms 19 ms 0 ms
75 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
76 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
77 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 39 ms
78 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 39 ms 39 ms 39 ms
79 * 6 128.32.197.4 (128.32.197.4) 40 ms 59 ms 59 ms
80 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 59 ms
81 * 8 129.140.70.13 (129.140.70.13) 99 ms 99 ms 80 ms
82 * 9 129.140.71.6 (129.140.71.6) 139 ms 239 ms 319 ms
83 * 10 129.140.81.7 (129.140.81.7) 220 ms 199 ms 199 ms
84 * 11 nic.merit.edu (35.1.1.48) 239 ms 239 ms 239 ms
86 * Note that lines 2 & 3 are the same. This is due to a buggy
87 * kernel on the 2nd hop system -- lbl-csam.arpa -- that forwards
88 * packets with a zero ttl.
90 * A more interesting example is:
92 * [yak 72]% traceroute allspice.lcs.mit.edu.
93 * traceroute to allspice.lcs.mit.edu (18.26.0.115), 30 hops max
94 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
95 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms
96 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms
97 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms
98 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms
99 * 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms
100 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms
101 * 8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms
102 * 9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms
103 * 10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms
104 * 11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms
106 * 13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms
111 * 18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms
113 * (I start to see why I'm having so much trouble with mail to
114 * MIT.) Note that the gateways 12, 14, 15, 16 & 17 hops away
115 * either don't send ICMP "time exceeded" messages or send them
116 * with a ttl too small to reach us. 14 - 17 are running the
117 * MIT C Gateway code that doesn't send "time exceeded"s. God
118 * only knows what's going on with 12.
120 * The silent gateway 12 in the above may be the result of a bug in
121 * the 4.[23]BSD network code (and its derivatives): 4.x (x <= 3)
122 * sends an unreachable message using whatever ttl remains in the
123 * original datagram. Since, for gateways, the remaining ttl is
124 * zero, the icmp "time exceeded" is guaranteed to not make it back
125 * to us. The behavior of this bug is slightly more interesting
126 * when it appears on the destination system:
128 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
129 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 39 ms
130 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 39 ms 19 ms
131 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 19 ms
132 * 5 ccn-nerif35.Berkeley.EDU (128.32.168.35) 39 ms 39 ms 39 ms
133 * 6 csgw.Berkeley.EDU (128.32.133.254) 39 ms 59 ms 39 ms
140 * 13 rip.Berkeley.EDU (128.32.131.22) 59 ms ! 39 ms ! 39 ms !
142 * Notice that there are 12 "gateways" (13 is the final
143 * destination) and exactly the last half of them are "missing".
144 * What's really happening is that rip (a Sun-3 running Sun OS3.5)
145 * is using the ttl from our arriving datagram as the ttl in its
146 * icmp reply. So, the reply will time out on the return path
147 * (with no notice sent to anyone since icmp's aren't sent for
148 * icmp's) until we probe with a ttl that's at least twice the path
149 * length. I.e., rip is really only 7 hops away. A reply that
150 * returns with a ttl of 1 is a clue this problem exists.
151 * Traceroute prints a "!" after the time if the ttl is <= 1.
152 * Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or
153 * non-standard (HPUX) software, expect to see this problem
154 * frequently and/or take care picking the target host of your
157 * Other possible annotations after the time are !H, !N, !P (got a host,
158 * network or protocol unreachable, respectively), !S or !F (source
159 * route failed or fragmentation needed -- neither of these should
160 * ever occur and the associated gateway is busted if you see one). If
161 * almost all the probes result in some kind of unreachable, traceroute
162 * will give up and exit.
166 * This program must be run by root or be setuid. (I suggest that
167 * you *don't* make it setuid -- casual use could result in a lot
168 * of unnecessary traffic on our poor, congested nets.)
170 * This program requires a kernel mod that does not appear in any
171 * system available from Berkeley: A raw ip socket using proto
172 * IPPROTO_RAW must interpret the data sent as an ip datagram (as
173 * opposed to data to be wrapped in a ip datagram). See the README
174 * file that came with the source to this program for a description
175 * of the mods I made to /sys/netinet/raw_ip.c. Your mileage may
176 * vary. But, again, ANY 4.x (x < 4) BSD KERNEL WILL HAVE TO BE
177 * MODIFIED TO RUN THIS PROGRAM.
179 * The udp port usage may appear bizarre (well, ok, it is bizarre).
180 * The problem is that an icmp message only contains 8 bytes of
181 * data from the original datagram. 8 bytes is the size of a udp
182 * header so, if we want to associate replies with the original
183 * datagram, the necessary information must be encoded into the
184 * udp header (the ip id could be used but there's no way to
185 * interlock with the kernel's assignment of ip id's and, anyway,
186 * it would have taken a lot more kernel hacking to allow this
187 * code to set the ip id). So, to allow two or more users to
188 * use traceroute simultaneously, we use this task's pid as the
189 * source port (the high bit is set to move the port number out
190 * of the "likely" range). To keep track of which probe is being
191 * replied to (so times and/or hop counts don't get confused by a
192 * reply that was delayed in transit), we increment the destination
193 * port number before each probe.
195 * Don't use this as a coding example. I was trying to find a
196 * routing problem and this code sort-of popped out after 48 hours
197 * without sleep. I was amazed it ever compiled, much less ran.
199 * I stole the idea for this program from Steve Deering. Since
200 * the first release, I've learned that had I attended the right
201 * IETF working group meetings, I also could have stolen it from Guy
202 * Almes or Matt Mathis. I don't know (or care) who came up with
203 * the idea first. I envy the originators' perspicacity and I'm
204 * glad they didn't keep the idea a secret.
206 * Tim Seaver, Ken Adelman and C. Philip Wood provided bug fixes and/or
207 * enhancements to the original distribution.
209 * I've hacked up a round-trip-route version of this that works by
210 * sending a loose-source-routed udp datagram through the destination
211 * back to yourself. Unfortunately, SO many gateways botch source
212 * routing, the thing is almost worthless. Maybe one day...
214 * -- Van Jacobson (van@helios.ee.lbl.gov)
215 * Tue Dec 20 03:50:13 PST 1988
218 #include <sys/param.h>
219 #include <sys/time.h>
220 #include <sys/socket.h>
221 #include <sys/file.h>
222 #include <sys/ioctl.h>
224 #include <netinet/in_systm.h>
225 #include <netinet/in.h>
226 #include <netinet/ip.h>
227 #include <netinet/ip_icmp.h>
228 #include <netinet/udp.h>
230 #include <arpa/inet.h>
239 #define MAXPACKET 65535 /* max ip packet size */
240 #ifndef MAXHOSTNAMELEN
241 #define MAXHOSTNAMELEN 64
245 #define NFDBITS (8*sizeof(fd_set))
246 #define FD_SETSIZE NFDBITS
247 #define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
248 #define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
249 #define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
250 #define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
253 #define Fprintf (void)fprintf
254 #define Sprintf (void)sprintf
255 #define Printf (void)printf
258 * format of a (udp) probe packet.
263 u_char seq; /* sequence number of this packet */
264 u_char ttl; /* ttl packet left with */
265 struct timeval tv; /* time packet left */
268 u_char packet[512]; /* last inbound (icmp) packet */
269 struct opacket *outpacket; /* last output (udp) packet */
271 int wait_for_reply __P((int, struct sockaddr_in *, struct timeval *));
272 void send_probe __P((int, int));
273 double deltaT __P((struct timeval *, struct timeval *));
274 int packet_ok __P((u_char *, int, struct sockaddr_in *, int));
275 void print __P((u_char *, int, struct sockaddr_in *));
276 void tvsub __P((struct timeval *, struct timeval *));
277 char *inetname __P((struct in_addr));
280 int s; /* receive (icmp) socket file descriptor */
281 int sndsock; /* send (udp) socket file descriptor */
282 struct timezone tz; /* leftover */
284 struct sockaddr whereto; /* Who to try to reach */
285 int datalen; /* How much data */
293 u_short port = 32768+666; /* start udp dest port # for probe packets */
294 int options; /* socket options */
296 int waittime = 5; /* time to wait for response (in seconds) */
297 int nflag; /* print addresses numerically */
308 struct sockaddr_in from, *to;
309 int ch, i, on, probe, seq, tos, ttl;
313 to = (struct sockaddr_in *)&whereto;
314 while ((ch = getopt(argc, argv, "dm:np:q:rs:t:w:v")) != EOF)
320 max_ttl = atoi(optarg);
323 "traceroute: max ttl must be >1.\n");
334 "traceroute: port must be >0.\n");
339 nprobes = atoi(optarg);
342 "traceroute: nprobes must be >0.\n");
347 options |= SO_DONTROUTE;
351 * set the ip source address of the outbound
352 * probe (e.g., on a multi-homed host).
358 if (tos < 0 || tos > 255) {
360 "traceroute: tos must be 0 to 255.\n");
368 waittime = atoi(optarg);
371 "traceroute: wait must be >1 sec.\n");
386 (void) bzero((char *)&whereto, sizeof(struct sockaddr));
387 to->sin_family = AF_INET;
388 to->sin_addr.s_addr = inet_addr(*argv);
389 if (to->sin_addr.s_addr != -1)
392 hp = gethostbyname(*argv);
394 to->sin_family = hp->h_addrtype;
395 bcopy(hp->h_addr, (caddr_t)&to->sin_addr, hp->h_length);
396 hostname = strdup(hp->h_name);
398 (void)fprintf(stderr,
399 "traceroute: unknown host %s\n", *argv);
404 datalen = atoi(*argv);
405 if (datalen < 0 || datalen >= MAXPACKET - sizeof(struct opacket)) {
407 "traceroute: packet size must be 0 <= s < %ld.\n",
408 MAXPACKET - sizeof(struct opacket));
411 datalen += sizeof(struct opacket);
412 outpacket = (struct opacket *)malloc((unsigned)datalen);
414 perror("traceroute: malloc");
417 (void) bzero((char *)outpacket, datalen);
418 outpacket->ip.ip_dst = to->sin_addr;
419 outpacket->ip.ip_tos = tos;
420 outpacket->ip.ip_v = IPVERSION;
421 outpacket->ip.ip_id = 0;
423 ident = (getpid() & 0xffff) | 0x8000;
425 if ((pe = getprotobyname("icmp")) == NULL) {
426 Fprintf(stderr, "icmp: unknown protocol\n");
429 if ((s = socket(AF_INET, SOCK_RAW, pe->p_proto)) < 0) {
430 perror("traceroute: icmp socket");
433 if (options & SO_DEBUG)
434 (void) setsockopt(s, SOL_SOCKET, SO_DEBUG,
435 (char *)&on, sizeof(on));
436 if (options & SO_DONTROUTE)
437 (void) setsockopt(s, SOL_SOCKET, SO_DONTROUTE,
438 (char *)&on, sizeof(on));
440 if ((sndsock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) {
441 perror("traceroute: raw socket");
445 if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, (char *)&datalen,
446 sizeof(datalen)) < 0) {
447 perror("traceroute: SO_SNDBUF");
452 if (setsockopt(sndsock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
454 perror("traceroute: IP_HDRINCL");
458 if (options & SO_DEBUG)
459 (void) setsockopt(sndsock, SOL_SOCKET, SO_DEBUG,
460 (char *)&on, sizeof(on));
461 if (options & SO_DONTROUTE)
462 (void) setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE,
463 (char *)&on, sizeof(on));
466 (void) bzero((char *)&from, sizeof(struct sockaddr));
467 from.sin_family = AF_INET;
468 from.sin_addr.s_addr = inet_addr(source);
469 if (from.sin_addr.s_addr == -1) {
470 Printf("traceroute: unknown host %s\n", source);
473 outpacket->ip.ip_src = from.sin_addr;
475 if (bind(sndsock, (struct sockaddr *)&from, sizeof(from)) < 0) {
476 perror ("traceroute: bind:");
482 Fprintf(stderr, "traceroute to %s (%s)", hostname,
483 inet_ntoa(to->sin_addr));
485 Fprintf(stderr, " from %s", source);
486 Fprintf(stderr, ", %d hops max, %d byte packets\n", max_ttl, datalen);
487 (void) fflush(stderr);
489 for (ttl = 1; ttl <= max_ttl; ++ttl) {
495 for (probe = 0; probe < nprobes; ++probe) {
497 struct timeval t1, t2;
501 (void) gettimeofday(&t1, &tz);
502 send_probe(++seq, ttl);
503 while (cc = wait_for_reply(s, &from, &t1)) {
504 (void) gettimeofday(&t2, &tz);
505 if ((i = packet_ok(packet, cc, &from, seq))) {
506 if (from.sin_addr.s_addr != lastaddr) {
507 print(packet, cc, &from);
508 lastaddr = from.sin_addr.s_addr;
510 Printf(" %.3f ms", deltaT(&t1, &t2));
512 case ICMP_UNREACH_PORT:
514 ip = (struct ip *)packet;
520 case ICMP_UNREACH_NET:
524 case ICMP_UNREACH_HOST:
528 case ICMP_UNREACH_PROTOCOL:
532 case ICMP_UNREACH_NEEDFRAG:
536 case ICMP_UNREACH_SRCFAIL:
546 (void) fflush(stdout);
549 if (got_there || unreachable >= nprobes-1)
555 wait_for_reply(sock, from, sent)
557 struct sockaddr_in *from;
558 struct timeval *sent;
561 struct timeval now, wait;
563 int fromlen = sizeof (*from);
567 gettimeofday(&now, NULL);
568 wait.tv_sec = (sent->tv_sec + waittime) - now.tv_sec;
569 wait.tv_usec = sent->tv_usec - now.tv_usec;
570 if (wait.tv_usec < 0) {
571 wait.tv_usec += 1000000;
575 wait.tv_sec = wait.tv_usec = 0;
577 if (select(sock+1, &fds, (fd_set *)0, (fd_set *)0, &wait) > 0)
578 cc=recvfrom(s, (char *)packet, sizeof(packet), 0,
579 (struct sockaddr *)from, &fromlen);
589 struct opacket *op = outpacket;
590 struct ip *ip = &op->ip;
591 struct udphdr *up = &op->udp;
595 ip->ip_hl = sizeof(*ip) >> 2;
596 ip->ip_p = IPPROTO_UDP;
597 ip->ip_len = datalen;
599 ip->ip_v = IPVERSION;
600 ip->ip_id = htons(ident+seq);
602 up->uh_sport = htons(ident);
603 up->uh_dport = htons(port+seq);
604 up->uh_ulen = htons((u_short)(datalen - sizeof(struct ip)));
609 (void) gettimeofday(&op->tv, &tz);
611 i = sendto(sndsock, (char *)outpacket, datalen, 0, &whereto,
612 sizeof(struct sockaddr));
613 if (i < 0 || i != datalen) {
616 Printf("traceroute: wrote %s %d chars, ret=%d\n", hostname,
618 (void) fflush(stdout);
625 struct timeval *t1p, *t2p;
629 dt = (double)(t2p->tv_sec - t1p->tv_sec) * 1000.0 +
630 (double)(t2p->tv_usec - t1p->tv_usec) / 1000.0;
636 * Convert an ICMP "type" field to a printable string.
642 static char *ttab[] = {
643 "Echo Reply", "ICMP 1", "ICMP 2", "Dest Unreachable",
644 "Source Quench", "Redirect", "ICMP 6", "ICMP 7",
645 "Echo", "ICMP 9", "ICMP 10", "Time Exceeded",
646 "Param Problem", "Timestamp", "Timestamp Reply", "Info Request",
651 return("OUT-OF-RANGE");
658 packet_ok(buf, cc, from, seq)
661 struct sockaddr_in *from;
664 register struct icmp *icp;
670 ip = (struct ip *) buf;
671 hlen = ip->ip_hl << 2;
672 if (cc < hlen + ICMP_MINLEN) {
674 Printf("packet too short (%d bytes) from %s\n", cc,
675 inet_ntoa(from->sin_addr));
679 icp = (struct icmp *)(buf + hlen);
681 icp = (struct icmp *)buf;
683 type = icp->icmp_type; code = icp->icmp_code;
684 if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS) ||
685 type == ICMP_UNREACH) {
690 hlen = hip->ip_hl << 2;
691 up = (struct udphdr *)((u_char *)hip + hlen);
692 if (hlen + 12 <= cc && hip->ip_p == IPPROTO_UDP &&
693 up->uh_sport == htons(ident) &&
694 up->uh_dport == htons(port+seq))
695 return (type == ICMP_TIMXCEED? -1 : code+1);
700 u_long *lp = (u_long *)&icp->icmp_ip;
702 Printf("\n%d bytes from %s to %s", cc,
703 inet_ntoa(from->sin_addr), inet_ntoa(ip->ip_dst));
704 Printf(": icmp type %d (%s) code %d\n", type, pr_type(type),
706 for (i = 4; i < cc ; i += sizeof(long))
707 Printf("%2d: x%8.8lx\n", i, *lp++);
718 struct sockaddr_in *from;
723 ip = (struct ip *) buf;
724 hlen = ip->ip_hl << 2;
728 Printf(" %s", inet_ntoa(from->sin_addr));
730 Printf(" %s (%s)", inetname(from->sin_addr),
731 inet_ntoa(from->sin_addr));
734 Printf (" %d bytes to %s", cc, inet_ntoa (ip->ip_dst));
740 * Checksum routine for Internet Protocol family headers (C Version)
747 register int nleft = len;
748 register u_short *w = addr;
749 register u_short answer;
750 register int sum = 0;
753 * Our algorithm is simple, using a 32 bit accumulator (sum),
754 * we add sequential 16 bit words to it, and at the end, fold
755 * back all the carry bits from the top 16 bits into the lower
763 /* mop up an odd byte, if necessary */
768 * add back carry outs from top 16 bits to low 16 bits
770 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
771 sum += (sum >> 16); /* add carry */
772 answer = ~sum; /* truncate to 16 bits */
778 * Subtract 2 timeval structs: out = out - in.
779 * Out is assumed to be >= in.
783 register struct timeval *out, *in;
785 if ((out->tv_usec -= in->tv_usec) < 0) {
787 out->tv_usec += 1000000;
789 out->tv_sec -= in->tv_sec;
794 * Construct an Internet address representation.
795 * If the nflag has been supplied, give
796 * numeric value, otherwise try for symbolic name.
803 static char line[50];
805 static char domain[MAXHOSTNAMELEN + 1];
806 static int first = 1;
808 if (first && !nflag) {
810 if (gethostname(domain, MAXHOSTNAMELEN) == 0 &&
811 (cp = index(domain, '.')))
812 (void) strcpy(domain, cp + 1);
817 if (!nflag && in.s_addr != INADDR_ANY) {
818 hp = gethostbyaddr((char *)&in, sizeof (in), AF_INET);
820 if ((cp = index(hp->h_name, '.')) &&
821 !strcmp(cp + 1, domain))
827 (void) strcpy(line, cp);
829 in.s_addr = ntohl(in.s_addr);
830 #define C(x) ((x) & 0xff)
831 Sprintf(line, "%lu.%lu.%lu.%lu", C(in.s_addr >> 24),
832 C(in.s_addr >> 16), C(in.s_addr >> 8), C(in.s_addr));
840 (void)fprintf(stderr,
841 "usage: traceroute [-dnrv] [-m max_ttl] [-p port#] [-q nqueries]\n\t\
842 [-s src_addr] [-t tos] [-w wait] host [data size]\n");