1 /* vi: set sw=4 ts=4: */
3 * Copyright (c) 1988, 1989, 1991, 1994, 1995, 1996, 1997, 1998, 1999, 2000
4 * The Regents of the University of California. All rights reserved.
6 * Busybox port by Vladimir Oleynik (C) 2005 <dzo@simtreas.ru>
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that: (1) source code distributions
10 * retain the above copyright notice and this paragraph in its entirety, (2)
11 * distributions including binary code include the above copyright notice and
12 * this paragraph in its entirety in the documentation or other materials
13 * provided with the distribution, and (3) all advertising materials mentioning
14 * features or use of this software display the following acknowledgement:
15 * ``This product includes software developed by the University of California,
16 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
17 * the University nor the names of its contributors may be used to endorse
18 * or promote products derived from this software without specific prior
20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
21 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
25 //#define version "1.4a12"
29 * traceroute host - trace the route ip packets follow going to "host".
31 * Attempt to trace the route an ip packet would follow to some
32 * internet host. We find out intermediate hops by launching probe
33 * packets with a small ttl (time to live) then listening for an
34 * icmp "time exceeded" reply from a gateway. We start our probes
35 * with a ttl of one and increase by one until we get an icmp "port
36 * unreachable" (which means we got to "host") or hit a max (which
37 * defaults to 30 hops & can be changed with the -m flag). Three
38 * probes (change with -q flag) are sent at each ttl setting and a
39 * line is printed showing the ttl, address of the gateway and
40 * round trip time of each probe. If the probe answers come from
41 * different gateways, the address of each responding system will
42 * be printed. If there is no response within a 5 sec. timeout
43 * interval (changed with the -w flag), a "*" is printed for that
46 * Probe packets are UDP format. We don't want the destination
47 * host to process them so the destination port is set to an
48 * unlikely value (if some clod on the destination is using that
49 * value, it can be changed with the -p flag).
51 * A sample use might be:
53 * [yak 71]% traceroute nis.nsf.net.
54 * traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 56 byte packet
55 * 1 helios.ee.lbl.gov (128.3.112.1) 19 ms 19 ms 0 ms
56 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
57 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
58 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 39 ms
59 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 39 ms 39 ms 39 ms
60 * 6 128.32.197.4 (128.32.197.4) 40 ms 59 ms 59 ms
61 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 59 ms
62 * 8 129.140.70.13 (129.140.70.13) 99 ms 99 ms 80 ms
63 * 9 129.140.71.6 (129.140.71.6) 139 ms 239 ms 319 ms
64 * 10 129.140.81.7 (129.140.81.7) 220 ms 199 ms 199 ms
65 * 11 nic.merit.edu (35.1.1.48) 239 ms 239 ms 239 ms
67 * Note that lines 2 & 3 are the same. This is due to a buggy
68 * kernel on the 2nd hop system -- lbl-csam.arpa -- that forwards
69 * packets with a zero ttl.
71 * A more interesting example is:
73 * [yak 72]% traceroute allspice.lcs.mit.edu.
74 * traceroute to allspice.lcs.mit.edu (18.26.0.115), 30 hops max
75 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
76 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms
77 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms
78 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms
79 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms
80 * 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms
81 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms
82 * 8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms
83 * 9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms
84 * 10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms
85 * 11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms
87 * 13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms
92 * 18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms
94 * (I start to see why I'm having so much trouble with mail to
95 * MIT.) Note that the gateways 12, 14, 15, 16 & 17 hops away
96 * either don't send ICMP "time exceeded" messages or send them
97 * with a ttl too small to reach us. 14 - 17 are running the
98 * MIT C Gateway code that doesn't send "time exceeded"s. God
99 * only knows what's going on with 12.
101 * The silent gateway 12 in the above may be the result of a bug in
102 * the 4.[23]BSD network code (and its derivatives): 4.x (x <= 3)
103 * sends an unreachable message using whatever ttl remains in the
104 * original datagram. Since, for gateways, the remaining ttl is
105 * zero, the icmp "time exceeded" is guaranteed to not make it back
106 * to us. The behavior of this bug is slightly more interesting
107 * when it appears on the destination system:
109 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
110 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 39 ms
111 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 39 ms 19 ms
112 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 19 ms
113 * 5 ccn-nerif35.Berkeley.EDU (128.32.168.35) 39 ms 39 ms 39 ms
114 * 6 csgw.Berkeley.EDU (128.32.133.254) 39 ms 59 ms 39 ms
121 * 13 rip.Berkeley.EDU (128.32.131.22) 59 ms ! 39 ms ! 39 ms !
123 * Notice that there are 12 "gateways" (13 is the final
124 * destination) and exactly the last half of them are "missing".
125 * What's really happening is that rip (a Sun-3 running Sun OS3.5)
126 * is using the ttl from our arriving datagram as the ttl in its
127 * icmp reply. So, the reply will time out on the return path
128 * (with no notice sent to anyone since icmp's aren't sent for
129 * icmp's) until we probe with a ttl that's at least twice the path
130 * length. I.e., rip is really only 7 hops away. A reply that
131 * returns with a ttl of 1 is a clue this problem exists.
132 * Traceroute prints a "!" after the time if the ttl is <= 1.
133 * Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or
134 * non-standard (HPUX) software, expect to see this problem
135 * frequently and/or take care picking the target host of your
138 * Other possible annotations after the time are !H, !N, !P (got a host,
139 * network or protocol unreachable, respectively), !S or !F (source
140 * route failed or fragmentation needed -- neither of these should
141 * ever occur and the associated gateway is busted if you see one). If
142 * almost all the probes result in some kind of unreachable, traceroute
143 * will give up and exit.
147 * This program must be run by root or be setuid. (I suggest that
148 * you *don't* make it setuid -- casual use could result in a lot
149 * of unnecessary traffic on our poor, congested nets.)
151 * This program requires a kernel mod that does not appear in any
152 * system available from Berkeley: A raw ip socket using proto
153 * IPPROTO_RAW must interpret the data sent as an ip datagram (as
154 * opposed to data to be wrapped in a ip datagram). See the README
155 * file that came with the source to this program for a description
156 * of the mods I made to /sys/netinet/raw_ip.c. Your mileage may
157 * vary. But, again, ANY 4.x (x < 4) BSD KERNEL WILL HAVE TO BE
158 * MODIFIED TO RUN THIS PROGRAM.
160 * The udp port usage may appear bizarre (well, ok, it is bizarre).
161 * The problem is that an icmp message only contains 8 bytes of
162 * data from the original datagram. 8 bytes is the size of a udp
163 * header so, if we want to associate replies with the original
164 * datagram, the necessary information must be encoded into the
165 * udp header (the ip id could be used but there's no way to
166 * interlock with the kernel's assignment of ip id's and, anyway,
167 * it would have taken a lot more kernel hacking to allow this
168 * code to set the ip id). So, to allow two or more users to
169 * use traceroute simultaneously, we use this task's pid as the
170 * source port (the high bit is set to move the port number out
171 * of the "likely" range). To keep track of which probe is being
172 * replied to (so times and/or hop counts don't get confused by a
173 * reply that was delayed in transit), we increment the destination
174 * port number before each probe.
176 * Don't use this as a coding example. I was trying to find a
177 * routing problem and this code sort-of popped out after 48 hours
178 * without sleep. I was amazed it ever compiled, much less ran.
180 * I stole the idea for this program from Steve Deering. Since
181 * the first release, I've learned that had I attended the right
182 * IETF working group meetings, I also could have stolen it from Guy
183 * Almes or Matt Mathis. I don't know (or care) who came up with
184 * the idea first. I envy the originators' perspicacity and I'm
185 * glad they didn't keep the idea a secret.
187 * Tim Seaver, Ken Adelman and C. Philip Wood provided bug fixes and/or
188 * enhancements to the original distribution.
190 * I've hacked up a round-trip-route version of this that works by
191 * sending a loose-source-routed udp datagram through the destination
192 * back to yourself. Unfortunately, SO many gateways botch source
193 * routing, the thing is almost worthless. Maybe one day...
195 * -- Van Jacobson (van@ee.lbl.gov)
196 * Tue Dec 20 03:50:13 PST 1988
199 #define TRACEROUTE_SO_DEBUG 0
201 /* TODO: undefs were uncommented - ??! we have config system for that! */
202 /* probably ok to remove altogether */
203 //#undef CONFIG_FEATURE_TRACEROUTE_VERBOSE
204 //#define CONFIG_FEATURE_TRACEROUTE_VERBOSE
205 //#undef CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE
206 //#define CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE
207 //#undef CONFIG_FEATURE_TRACEROUTE_USE_ICMP
208 //#define CONFIG_FEATURE_TRACEROUTE_USE_ICMP
212 #include <arpa/inet.h>
213 #include <netinet/in.h>
214 #include <netinet/udp.h>
215 #include <netinet/ip.h>
216 #include <netinet/ip_icmp.h>
219 #include "inet_common.h"
223 * Definitions for internet protocol version 4.
224 * Per RFC 791, September 1981.
230 #define IPPROTO_ICMP 1
237 * Overlay for ip header used by other protocols (tcp, udp).
240 unsigned char ih_x1[9]; /* (unused) */
241 unsigned char ih_pr; /* protocol */
242 short ih_len; /* protocol length */
243 struct in_addr ih_src; /* source internet address */
244 struct in_addr ih_dst; /* destination internet address */
248 * UDP kernel structures and variables.
251 struct ipovly ui_i; /* overlaid ip structure */
252 struct udphdr ui_u; /* udp header */
254 #define ui_next ui_i.ih_next
255 #define ui_prev ui_i.ih_prev
256 #define ui_x1 ui_i.ih_x1
257 #define ui_pr ui_i.ih_pr
258 #define ui_len ui_i.ih_len
259 #define ui_src ui_i.ih_src
260 #define ui_dst ui_i.ih_dst
261 #define ui_sport ui_u.uh_sport
262 #define ui_dport ui_u.uh_dport
263 #define ui_ulen ui_u.uh_ulen
264 #define ui_sum ui_u.uh_sum
267 /* Host name and address list */
274 /* Data section of the probe packet */
276 unsigned char seq; /* sequence number of this packet */
277 unsigned char ttl; /* ttl packet left with */
278 // UNUSED. Retaining to have the same packet size.
279 struct timeval tv_UNUSED ATTRIBUTE_PACKED; /* time packet left */
284 char device[sizeof(struct ifreq)];
288 static struct ip *outip; /* last output (udp) packet */
289 static struct udphdr *outudp; /* last output (udp) packet */
290 static struct outdata *outdata; /* last output (udp) packet */
292 #if ENABLE_FEATURE_TRACEROUTE_USE_ICMP
293 static struct icmp *outicmp; /* last output (icmp) packet */
296 static int s; /* receive (icmp) socket file descriptor */
297 static int sndsock; /* send (udp/icmp) socket file descriptor */
299 static int packlen; /* total length of packet */
300 static int minpacket; /* min ip packet size */
301 static int maxpacket = 32 * 1024; /* max ip packet size */
302 static int pmtu; /* Path MTU Discovery (RFC1191) */
304 static char *hostname;
306 static uint16_t ident;
307 static uint16_t port = 32768 + 666; /* start udp dest port # for probe packets */
309 static int waittime = 5; /* time to wait for response (in seconds) */
310 static int doipcksum = 1; /* calculate ip checksums by default */
312 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
313 static int optlen; /* length of ip options */
319 /* Keep in sync with getopt32 call! */
320 #define OPT_DONT_FRAGMNT (1<<0) /* F */
321 #define OPT_USE_ICMP (1<<1) /* I */
322 #define OPT_TTL_FLAG (1<<2) /* l */
323 #define OPT_ADDR_NUM (1<<3) /* n */
324 #define OPT_BYPASS_ROUTE (1<<4) /* r */
325 #define OPT_DEBUG (1<<5) /* d */
326 #define OPT_VERBOSE (1<<6) /* v */
327 #define OPT_IP_CHKSUM (1<<7) /* x */
328 #define OPT_TOS (1<<8) /* t */
329 #define OPT_DEVICE (1<<9) /* i */
330 #define OPT_MAX_TTL (1<<10) /* m */
331 #define OPT_PORT (1<<11) /* p */
332 #define OPT_NPROBES (1<<12) /* q */
333 #define OPT_SOURCE (1<<13) /* s */
334 #define OPT_WAITTIME (1<<14) /* w */
335 #define OPT_PAUSE_MS (1<<15) /* z */
336 #define OPT_FIRST_TTL (1<<16) /* f */
338 #if ENABLE_FEATURE_TRACEROUTE_USE_ICMP
339 /* use icmp echo instead of udp packets */
340 #define useicmp (option_mask32 & OPT_USE_ICMP)
342 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
343 #define verbose (option_mask32 & OPT_VERBOSE)
345 #define nflag (option_mask32 & OPT_ADDR_NUM)
349 struct sockaddr_storage whereto; /* Who to try to reach */
350 struct sockaddr_storage wherefrom; /* Who we are */
351 /* last inbound (icmp) packet */
352 unsigned char packet[512];
353 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
354 /* Maximum number of gateways (include room for one noop) */
355 #define NGATEWAYS ((int)((MAX_IPOPTLEN - IPOPT_MINOFF - 1) / sizeof(uint32_t)))
356 /* loose source route gateway list (including room for final destination) */
357 uint32_t gwlist[NGATEWAYS + 1];
361 #define G (*ptr_to_globals)
362 #define INIT_G() PTR_TO_GLOBALS = xzalloc(sizeof(G))
363 #define packet (G.packet )
364 #define whereto (G.whereto )
365 #define wherefrom (G.wherefrom)
366 #define gwlist (G.gwlist )
370 * Return the interface list
373 ifaddrlist(struct IFADDRLIST **ipaddrp)
375 enum { IFREQ_BUFSIZE = (32 * 1024) / sizeof(struct ifreq) };
378 #ifdef HAVE_SOCKADDR_SA_LEN
381 struct ifreq *ifrp, *ifend, *ifnext;
382 struct sockaddr_in *addr_sin;
383 struct IFADDRLIST *al;
386 /* Was on stack, but 32k is a bit too much: */
387 struct ifreq *ibuf = xmalloc(IFREQ_BUFSIZE * sizeof(ibuf[0]));
388 struct IFADDRLIST *st_ifaddrlist;
390 fd = xsocket(AF_INET, SOCK_DGRAM, 0);
392 ifc.ifc_len = IFREQ_BUFSIZE * sizeof(ibuf[0]);
393 ifc.ifc_buf = (caddr_t)ibuf;
395 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
396 || ifc.ifc_len < sizeof(struct ifreq)
399 bb_error_msg_and_die(
400 "SIOCGIFCONF: ifreq struct too small (%u bytes)",
401 (unsigned)(IFREQ_BUFSIZE * sizeof(ibuf[0])));
402 bb_perror_msg_and_die("SIOCGIFCONF");
405 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
407 nipaddr = 1 + (ifc.ifc_len / sizeof(struct ifreq));
408 st_ifaddrlist = xzalloc(nipaddr * sizeof(struct IFADDRLIST));
412 for (; ifrp < ifend; ifrp = ifnext) {
413 #ifdef HAVE_SOCKADDR_SA_LEN
414 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
415 if (n < sizeof(*ifrp))
418 ifnext = (struct ifreq *)((char *)ifrp + n);
419 if (ifrp->ifr_addr.sa_family != AF_INET)
425 * Need a template to preserve address info that is
426 * used below to locate the next entry. (Otherwise,
427 * SIOCGIFFLAGS stomps over it because the requests
428 * are returned in a union.)
430 strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name));
431 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
434 bb_perror_msg_and_die("SIOCGIFFLAGS: %.*s",
435 (int)sizeof(ifr.ifr_name), ifr.ifr_name);
439 if ((ifr.ifr_flags & IFF_UP) == 0)
442 safe_strncpy(al->device, ifr.ifr_name, sizeof(ifr.ifr_name) + 1);
444 /* Ignore sun virtual interfaces */
445 if (strchr(al->device, ':') != NULL)
448 ioctl_or_perror_and_die(fd, SIOCGIFADDR, (char *)&ifr,
449 "SIOCGIFADDR: %s", al->device);
451 addr_sin = (struct sockaddr_in *)&ifr.ifr_addr;
452 al->addr = addr_sin->sin_addr.s_addr;
457 bb_error_msg_and_die("can't find any network interfaces");
461 *ipaddrp = st_ifaddrlist;
467 setsin(struct sockaddr_in *addr_sin, uint32_t addr)
469 memset(addr_sin, 0, sizeof(*addr_sin));
470 #ifdef HAVE_SOCKADDR_SA_LEN
471 addr_sin->sin_len = sizeof(*addr_sin);
473 addr_sin->sin_family = AF_INET;
474 addr_sin->sin_addr.s_addr = addr;
479 * Return the source address for the given destination address
482 findsaddr(const struct sockaddr_in *to, struct sockaddr_in *from)
487 uint32_t dest, tmask;
488 struct IFADDRLIST *al;
489 char buf[256], tdevice[256], device[256];
491 f = xfopen("/proc/net/route", "r");
493 /* Find the appropriate interface */
497 while (fgets(buf, sizeof(buf), f) != NULL) {
499 if (n == 1 && strncmp(buf, "Iface", 5) == 0)
501 i = sscanf(buf, "%255s %x %*s %*s %*s %*s %*s %x",
502 tdevice, &dest, &tmask);
504 bb_error_msg_and_die("junk in buffer");
505 if ((to->sin_addr.s_addr & tmask) == dest
506 && (tmask > mask || mask == 0)
509 strcpy(device, tdevice);
514 if (device[0] == '\0')
515 bb_error_msg_and_die("can't find interface");
517 /* Get the interface address list */
520 /* Find our appropriate source address */
521 for (i = n; i > 0; --i, ++al)
522 if (strcmp(device, al->device) == 0)
525 bb_error_msg_and_die("can't find interface %s", device);
527 setsin(from, al->addr);
531 "Usage: %s [-dFIlnrvx] [-g gateway] [-i iface] [-f first_ttl]\n"
532 "\t[-m max_ttl] [ -p port] [-q nqueries] [-s src_addr] [-t tos]\n"
533 "\t[-w waittime] [-z pausemsecs] host [packetlen]"
538 wait_for_reply(int sock, struct sockaddr_in *fromp)
540 struct pollfd pfd[1];
542 socklen_t fromlen = sizeof(*fromp);
545 pfd[0].events = POLLIN;
546 if (safe_poll(pfd, 1, waittime * 1000) > 0)
547 cc = recvfrom(sock, packet, sizeof(packet), 0,
548 (struct sockaddr *)fromp, &fromlen);
553 * Checksum routine for Internet Protocol family headers (C Version)
556 in_cksum(uint16_t *addr, int len)
564 * Our algorithm is simple, using a 32 bit accumulator (sum),
565 * we add sequential 16 bit words to it, and at the end, fold
566 * back all the carry bits from the top 16 bits into the lower
574 /* mop up an odd byte, if necessary */
576 sum += *(unsigned char *)w;
579 * add back carry outs from top 16 bits to low 16 bits
581 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
582 sum += (sum >> 16); /* add carry */
583 answer = ~sum; /* truncate to 16 bits */
589 send_probe(int seq, int ttl)
592 struct udpiphdr *ui, *oui;
596 outip->ip_id = htons(ident + seq);
599 * In most cases, the kernel will recalculate the ip checksum.
600 * But we must do it anyway so that the udp checksum comes out
605 in_cksum((uint16_t *)outip, sizeof(*outip) + optlen);
606 if (outip->ip_sum == 0)
607 outip->ip_sum = 0xffff;
613 // UNUSED: was storing gettimeofday's result there, but never ever checked it
614 /*memcpy(&outdata->tv, tp, sizeof(outdata->tv));*/
616 #if ENABLE_FEATURE_TRACEROUTE_USE_ICMP
618 outicmp->icmp_seq = htons(seq);
621 outudp->dest = htons(port + seq);
623 #if ENABLE_FEATURE_TRACEROUTE_USE_ICMP
625 /* Always calculate checksum for icmp packets */
626 outicmp->icmp_cksum = 0;
627 outicmp->icmp_cksum = in_cksum((uint16_t *)outicmp,
628 packlen - (sizeof(*outip) + optlen));
629 if (outicmp->icmp_cksum == 0)
630 outicmp->icmp_cksum = 0xffff;
634 /* Checksum (we must save and restore ip header) */
636 ui = (struct udpiphdr *)outip;
637 oui = (struct udpiphdr *)&tip;
638 /* Easier to zero and put back things that are ok */
639 memset((char *)ui, 0, sizeof(ui->ui_i));
640 ui->ui_src = oui->ui_src;
641 ui->ui_dst = oui->ui_dst;
642 ui->ui_pr = oui->ui_pr;
643 ui->ui_len = outudp->len;
645 outudp->check = in_cksum((uint16_t *)ui, packlen);
646 if (outudp->check == 0)
647 outudp->check = 0xffff;
651 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
652 /* XXX undocumented debugging hack */
657 sp = (uint16_t *)outip;
658 nshorts = (unsigned)packlen / sizeof(uint16_t);
660 printf("[ %d bytes", packlen);
661 while (--nshorts >= 0) {
664 printf(" %04x", ntohs(*sp));
670 printf(" %02x", *(unsigned char *)sp);
676 #if !defined(IP_HDRINCL) && defined(IP_TTL)
677 if (setsockopt(sndsock, IPPROTO_IP, IP_TTL,
678 (char *)&ttl, sizeof(ttl)) < 0) {
679 bb_perror_msg_and_die("setsockopt ttl %d", ttl);
683 cc = xsendto(sndsock, (char *)outip,
684 packlen, (struct sockaddr *)&whereto, sizeof(whereto));
686 bb_info_msg("wrote %s %d chars, ret=%d", hostname, packlen, cc);
690 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
692 * Convert an ICMP "type" field to a printable string.
694 static inline const char *
695 pr_type(unsigned char t)
697 static const char *const ttab[] = {
698 "Echo Reply", "ICMP 1", "ICMP 2", "Dest Unreachable",
699 "Source Quench", "Redirect", "ICMP 6", "ICMP 7",
700 "Echo", "Router Advert", "Router Solicit", "Time Exceeded",
701 "Param Problem", "Timestamp", "Timestamp Reply", "Info Request",
702 "Info Reply", "Mask Request", "Mask Reply"
706 return "OUT-OF-RANGE";
713 packet_ok(unsigned char *buf, int cc, struct sockaddr_in *from, int seq)
716 unsigned char type, code;
720 ip = (struct ip *) buf;
721 hlen = ip->ip_hl << 2;
722 if (cc < hlen + ICMP_MINLEN) {
723 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
725 printf("packet too short (%d bytes) from %s\n", cc,
726 inet_ntoa(from->sin_addr));
731 icp = (struct icmp *)(buf + hlen);
732 type = icp->icmp_type;
733 code = icp->icmp_code;
734 /* Path MTU Discovery (RFC1191) */
735 if (code != ICMP_UNREACH_NEEDFRAG)
738 pmtu = ntohs(icp->icmp_nextmtu);
740 if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS) ||
741 type == ICMP_UNREACH || type == ICMP_ECHOREPLY) {
746 hlen = hip->ip_hl << 2;
747 #if ENABLE_FEATURE_TRACEROUTE_USE_ICMP
752 if (type == ICMP_ECHOREPLY &&
753 icp->icmp_id == htons(ident) &&
754 icp->icmp_seq == htons(seq))
757 hicmp = (struct icmp *)((unsigned char *)hip + hlen);
758 /* XXX 8 is a magic number */
759 if (hlen + 8 <= cc &&
760 hip->ip_p == IPPROTO_ICMP &&
761 hicmp->icmp_id == htons(ident) &&
762 hicmp->icmp_seq == htons(seq))
763 return (type == ICMP_TIMXCEED ? -1 : code + 1);
767 up = (struct udphdr *)((unsigned char *)hip + hlen);
768 /* XXX 8 is a magic number */
769 if (hlen + 12 <= cc &&
770 hip->ip_p == IPPROTO_UDP &&
771 up->source == htons(ident) &&
772 up->dest == htons(port + seq))
773 return (type == ICMP_TIMXCEED ? -1 : code + 1);
776 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
779 uint32_t *lp = (uint32_t *)&icp->icmp_ip;
781 printf("\n%d bytes from %s to "
782 "%s: icmp type %d (%s) code %d\n",
783 cc, inet_ntoa(from->sin_addr),
784 inet_ntoa(ip->ip_dst), type, pr_type(type), icp->icmp_code);
785 for (i = 4; i < cc; i += sizeof(*lp))
786 printf("%2d: x%8.8x\n", i, *lp++);
794 * Construct an Internet address representation.
795 * If the nflag has been supplied, give
796 * numeric value, otherwise try for symbolic name.
799 print_inetname(struct sockaddr_in *from)
803 ina = inet_ntoa(from->sin_addr);
808 if (from->sin_addr.s_addr != INADDR_ANY)
809 n = xmalloc_sockaddr2host_noport((struct sockaddr*)from);
810 printf(" %s (%s)", (n ? n : ina), ina);
816 print(unsigned char *buf, int cc, struct sockaddr_in *from)
821 ip = (struct ip *) buf;
822 hlen = ip->ip_hl << 2;
825 print_inetname(from);
826 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
828 printf(" %d bytes to %s", cc, inet_ntoa(ip->ip_dst));
833 static struct hostinfo *
834 gethostinfo(const char *host)
842 hi = xzalloc(sizeof(*hi));
843 addr = inet_addr(host);
844 if (addr != 0xffffffff) {
845 hi->name = xstrdup(host);
847 hi->addrs = xzalloc(sizeof(hi->addrs[0]));
852 hp = xgethostbyname(host);
853 if (hp->h_addrtype != AF_INET || hp->h_length != 4)
854 bb_perror_msg_and_die("bad host %s", host);
855 hi->name = xstrdup(hp->h_name);
856 for (n = 0, p = hp->h_addr_list; *p != NULL; ++n, ++p)
859 hi->addrs = xzalloc(n * sizeof(hi->addrs[0]));
860 for (ap = hi->addrs, p = hp->h_addr_list; *p != NULL; ++ap, ++p)
861 memcpy(ap, *p, sizeof(*ap));
866 freehostinfo(struct hostinfo *hi)
873 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
875 getaddr(uint32_t *ap, const char *host)
879 hi = gethostinfo(host);
886 print_delta_ms(unsigned t1p, unsigned t2p)
888 unsigned tt = t2p - t1p;
889 printf(" %u.%03u ms", tt/1000, tt%1000);
892 int traceroute_main(int argc, char **argv);
893 int traceroute_main(int argc, char **argv)
898 struct sockaddr_in *from;
899 struct sockaddr_in *to;
907 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
911 struct IFADDRLIST *al;
919 unsigned pausemsecs = 0;
920 char *pausemsecs_str;
923 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
924 llist_t *source_route_list = NULL;
928 from = (struct sockaddr_in *)&wherefrom;
929 to = (struct sockaddr_in *)&whereto;
932 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
933 opt_complementary = "x-x:g::";
935 opt_complementary = "x-x";
938 op = getopt32(argv, "FIlnrdvxt:i:m:p:q:s:w:z:f:"
939 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
942 , &tos_str, &device, &max_ttl_str, &port_str, &nprobes_str
943 , &source, &waittime_str, &pausemsecs_str, &first_ttl_str
944 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
949 if (op & OPT_DONT_FRAGMNT)
951 if (op & OPT_IP_CHKSUM) {
953 bb_error_msg("warning: ip checksums disabled");
956 tos = xatou_range(tos_str, 0, 255);
957 if (op & OPT_MAX_TTL)
958 max_ttl = xatou_range(max_ttl_str, 1, 255);
960 port = xatou16(port_str);
961 if (op & OPT_NPROBES)
962 nprobes = xatou_range(nprobes_str, 1, INT_MAX);
963 if (op & OPT_SOURCE) {
965 * set the ip source address of the outbound
966 * probe (e.g., on a multi-homed host).
969 bb_error_msg_and_die("-s %s: permission denied", source);
971 if (op & OPT_WAITTIME)
972 waittime = xatou_range(waittime_str, 2, 24 * 60 * 60);
973 if (op & OPT_PAUSE_MS)
974 pausemsecs = xatou_range(pausemsecs_str, 0, 60 * 60 * 1000);
975 if (op & OPT_FIRST_TTL)
976 first_ttl = xatou_range(first_ttl_str, 1, 255);
978 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
979 if (source_route_list) {
982 l_sr = source_route_list;
984 if (lsrr >= NGATEWAYS)
985 bb_error_msg_and_die("no more than %d gateways", NGATEWAYS);
986 getaddr(gwlist + lsrr, l_sr->data);
989 free(source_route_list);
990 source_route_list = l_sr;
992 optlen = (lsrr + 1) * sizeof(gwlist[0]);
996 if (first_ttl > max_ttl) {
997 bb_error_msg_and_die(
998 "first ttl (%d) may not be greater than max ttl (%d)",
1002 minpacket = sizeof(*outip) + sizeof(*outdata) + optlen;
1004 #if ENABLE_FEATURE_TRACEROUTE_USE_ICMP
1006 minpacket += 8; /* XXX magic number */
1009 minpacket += sizeof(*outudp);
1010 packlen = minpacket; /* minimum sized packet */
1012 /* Process destination and optional packet size */
1013 switch (argc - optind) {
1016 packlen = xatoul_range(argv[optind + 1], minpacket, maxpacket);
1020 hostname = argv[optind];
1021 hi = gethostinfo(hostname);
1022 setsin(to, hi->addrs[0]);
1024 bb_error_msg("warning: %s has multiple addresses; using %s",
1025 hostname, inet_ntoa(to->sin_addr));
1026 hostname = hi->name;
1035 /* Ensure the socket fds won't be 0, 1 or 2 */
1036 bb_sanitize_stdio();
1038 s = xsocket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
1040 #if TRACEROUTE_SO_DEBUG
1042 setsockopt(s, SOL_SOCKET, SO_DEBUG,
1043 &const_int_1, sizeof(const_int_1));
1045 if (op & OPT_BYPASS_ROUTE)
1046 setsockopt(s, SOL_SOCKET, SO_DONTROUTE,
1047 &const_int_1, sizeof(const_int_1));
1049 sndsock = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW);
1051 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
1052 #if defined(IP_OPTIONS)
1054 unsigned char optlist[MAX_IPOPTLEN];
1057 gwlist[lsrr] = to->sin_addr.s_addr;
1060 /* force 4 byte alignment */
1061 optlist[0] = IPOPT_NOP;
1062 /* loose source route option */
1063 optlist[1] = IPOPT_LSRR;
1064 i = lsrr * sizeof(gwlist[0]);
1066 /* Pointer to LSRR addresses */
1067 optlist[3] = IPOPT_MINOFF;
1068 memcpy(optlist + 4, gwlist, i);
1070 if ((setsockopt(sndsock, IPPROTO_IP, IP_OPTIONS,
1071 (char *)optlist, i + sizeof(gwlist[0]))) < 0) {
1072 bb_perror_msg_and_die("IP_OPTIONS");
1075 #endif /* IP_OPTIONS */
1076 #endif /* CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE */
1079 if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, &packlen, sizeof(packlen)) < 0) {
1080 bb_perror_msg_and_die("SO_SNDBUF");
1084 if (setsockopt(sndsock, IPPROTO_IP, IP_HDRINCL, &const_int_1, sizeof(const_int_1)) < 0
1085 && errno != ENOPROTOOPT
1087 bb_perror_msg_and_die("IP_HDRINCL");
1091 if (tos_str && setsockopt(sndsock, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) {
1092 bb_perror_msg_and_die("setsockopt tos %d", tos);
1096 #if TRACEROUTE_SO_DEBUG
1098 setsockopt(sndsock, SOL_SOCKET, SO_DEBUG,
1099 &const_int_1, sizeof(const_int_1));
1101 if (op & OPT_BYPASS_ROUTE)
1102 setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE,
1103 &const_int_1, sizeof(const_int_1));
1105 /* Revert to non-privileged user after opening sockets */
1109 outip = xzalloc(packlen);
1111 outip->ip_v = IPVERSION;
1113 outip->ip_tos = tos;
1114 outip->ip_len = htons(packlen);
1115 outip->ip_off = htons(off);
1116 outp = (unsigned char *)(outip + 1);
1117 outip->ip_dst = to->sin_addr;
1119 outip->ip_hl = (outp - (unsigned char *)outip) >> 2;
1120 ident = (getpid() & 0xffff) | 0x8000;
1121 #if ENABLE_FEATURE_TRACEROUTE_USE_ICMP
1123 outip->ip_p = IPPROTO_ICMP;
1124 outicmp = (struct icmp *)outp;
1125 outicmp->icmp_type = ICMP_ECHO;
1126 outicmp->icmp_id = htons(ident);
1127 outdata = (struct outdata *)(outp + 8); /* XXX magic number */
1131 outip->ip_p = IPPROTO_UDP;
1132 outudp = (struct udphdr *)outp;
1133 outudp->source = htons(ident);
1134 outudp->len = htons((uint16_t)(packlen - (sizeof(*outip) + optlen)));
1135 outdata = (struct outdata *)(outudp + 1);
1138 /* Get the interface address list */
1139 n = ifaddrlist(&al);
1141 /* Look for a specific device */
1142 if (op & OPT_DEVICE) {
1143 for (i = n; i > 0; --i, ++al)
1144 if (strcmp(device, al->device) == 0)
1146 bb_error_msg_and_die("can't find interface %s", device);
1150 /* Determine our source address */
1151 if (!(op & OPT_SOURCE)) {
1153 * If a device was specified, use the interface address.
1154 * Otherwise, try to determine our source address.
1156 if (op & OPT_DEVICE)
1157 setsin(from, al->addr);
1158 findsaddr(to, from);
1160 hi = gethostinfo(source);
1164 * If the device was specified make sure it
1165 * corresponds to the source address specified.
1166 * Otherwise, use the first address (and warn if
1167 * there are more than one).
1169 if (op & OPT_DEVICE) {
1170 for (i = hi->n, ap = hi->addrs; i > 0; --i, ++ap)
1171 if (*ap == al->addr)
1173 bb_error_msg_and_die("%s is not on interface %s",
1178 setsin(from, hi->addrs[0]);
1181 "warning: %s has multiple addresses; using %s",
1182 source, inet_ntoa(from->sin_addr));
1187 outip->ip_src = from->sin_addr;
1189 xbind(sndsock, (struct sockaddr *)from, sizeof(*from));
1192 printf("traceroute to %s (%s)", hostname, inet_ntoa(to->sin_addr));
1193 if (op & OPT_SOURCE)
1194 printf(" from %s", source);
1195 printf(", %d hops max, %d byte packets\n", max_ttl, packlen);
1198 for (ttl = first_ttl; ttl <= max_ttl; ++ttl) {
1199 uint32_t lastaddr = 0;
1200 int gotlastaddr = 0;
1202 int unreachable = 0;
1205 printf("%2d ", ttl);
1206 for (probe = 0; probe < nprobes; ++probe) {
1212 if (sentfirst && pausemsecs > 0)
1213 usleep(pausemsecs * 1000);
1214 t1 = monotonic_us();
1215 send_probe(++seq, ttl);
1217 while ((cc = wait_for_reply(s, from)) != 0) {
1218 t2 = monotonic_us();
1219 i = packet_ok(packet, cc, from, seq);
1220 /* Skip short packet */
1224 from->sin_addr.s_addr != lastaddr) {
1225 print(packet, cc, from);
1226 lastaddr = from->sin_addr.s_addr;
1229 print_delta_ms(t1, t2);
1230 ip = (struct ip *)packet;
1231 if (op & OPT_TTL_FLAG)
1232 printf(" (%d)", ip->ip_ttl);
1234 if (ip->ip_ttl <= 1)
1239 /* time exceeded in transit */
1245 case ICMP_UNREACH_PORT:
1246 if (ip->ip_ttl <= 1)
1251 case ICMP_UNREACH_NET:
1256 case ICMP_UNREACH_HOST:
1261 case ICMP_UNREACH_PROTOCOL:
1266 case ICMP_UNREACH_NEEDFRAG:
1268 printf(" !F-%d", pmtu);
1271 case ICMP_UNREACH_SRCFAIL:
1276 case ICMP_UNREACH_FILTER_PROHIB:
1277 case ICMP_UNREACH_NET_PROHIB: /* misuse */
1282 case ICMP_UNREACH_HOST_PROHIB:
1287 case ICMP_UNREACH_HOST_PRECEDENCE:
1292 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
1297 case ICMP_UNREACH_NET_UNKNOWN:
1298 case ICMP_UNREACH_HOST_UNKNOWN:
1303 case ICMP_UNREACH_ISOLATED:
1308 case ICMP_UNREACH_TOSNET:
1309 case ICMP_UNREACH_TOSHOST:
1316 printf(" !<%d>", code);
1323 (void)fflush(stdout);
1327 (unreachable > 0 && unreachable >= nprobes - 1))