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.
28 * Modified for NRL 4.4BSD IPv6 release.
31 * Modified for Linux IPv6 by Pedro Roque <roque@di.fc.ul.pt>
34 * As ICMP error messages for IPv6 now include more than 8 bytes
35 * UDP datagrams are now sent via an UDP socket instead of magic
38 * Converted to busybox applet by Leonid Lisovskiy <lly@sf.net>
43 * traceroute host - trace the route ip packets follow going to "host".
45 * Attempt to trace the route an ip packet would follow to some
46 * internet host. We find out intermediate hops by launching probe
47 * packets with a small ttl (time to live) then listening for an
48 * icmp "time exceeded" reply from a gateway. We start our probes
49 * with a ttl of one and increase by one until we get an icmp "port
50 * unreachable" (which means we got to "host") or hit a max (which
51 * defaults to 30 hops & can be changed with the -m flag). Three
52 * probes (change with -q flag) are sent at each ttl setting and a
53 * line is printed showing the ttl, address of the gateway and
54 * round trip time of each probe. If the probe answers come from
55 * different gateways, the address of each responding system will
56 * be printed. If there is no response within a 5 sec. timeout
57 * interval (changed with the -w flag), a "*" is printed for that
60 * Probe packets are UDP format. We don't want the destination
61 * host to process them so the destination port is set to an
62 * unlikely value (if some clod on the destination is using that
63 * value, it can be changed with the -p flag).
65 * A sample use might be:
67 * [yak 71]% traceroute nis.nsf.net.
68 * traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 56 byte packet
69 * 1 helios.ee.lbl.gov (128.3.112.1) 19 ms 19 ms 0 ms
70 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
71 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
72 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 39 ms
73 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 39 ms 39 ms 39 ms
74 * 6 128.32.197.4 (128.32.197.4) 40 ms 59 ms 59 ms
75 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 59 ms
76 * 8 129.140.70.13 (129.140.70.13) 99 ms 99 ms 80 ms
77 * 9 129.140.71.6 (129.140.71.6) 139 ms 239 ms 319 ms
78 * 10 129.140.81.7 (129.140.81.7) 220 ms 199 ms 199 ms
79 * 11 nic.merit.edu (35.1.1.48) 239 ms 239 ms 239 ms
81 * Note that lines 2 & 3 are the same. This is due to a buggy
82 * kernel on the 2nd hop system -- lbl-csam.arpa -- that forwards
83 * packets with a zero ttl.
85 * A more interesting example is:
87 * [yak 72]% traceroute allspice.lcs.mit.edu.
88 * traceroute to allspice.lcs.mit.edu (18.26.0.115), 30 hops max
89 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
90 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms
91 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms
92 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms
93 * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms
94 * 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms
95 * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms
96 * 8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms
97 * 9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms
98 * 10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms
99 * 11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms
101 * 13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms
106 * 18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms
108 * (I start to see why I'm having so much trouble with mail to
109 * MIT.) Note that the gateways 12, 14, 15, 16 & 17 hops away
110 * either don't send ICMP "time exceeded" messages or send them
111 * with a ttl too small to reach us. 14 - 17 are running the
112 * MIT C Gateway code that doesn't send "time exceeded"s. God
113 * only knows what's going on with 12.
115 * The silent gateway 12 in the above may be the result of a bug in
116 * the 4.[23]BSD network code (and its derivatives): 4.x (x <= 3)
117 * sends an unreachable message using whatever ttl remains in the
118 * original datagram. Since, for gateways, the remaining ttl is
119 * zero, the icmp "time exceeded" is guaranteed to not make it back
120 * to us. The behavior of this bug is slightly more interesting
121 * when it appears on the destination system:
123 * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
124 * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 39 ms
125 * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 39 ms 19 ms
126 * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 19 ms
127 * 5 ccn-nerif35.Berkeley.EDU (128.32.168.35) 39 ms 39 ms 39 ms
128 * 6 csgw.Berkeley.EDU (128.32.133.254) 39 ms 59 ms 39 ms
135 * 13 rip.Berkeley.EDU (128.32.131.22) 59 ms ! 39 ms ! 39 ms !
137 * Notice that there are 12 "gateways" (13 is the final
138 * destination) and exactly the last half of them are "missing".
139 * What's really happening is that rip (a Sun-3 running Sun OS3.5)
140 * is using the ttl from our arriving datagram as the ttl in its
141 * icmp reply. So, the reply will time out on the return path
142 * (with no notice sent to anyone since icmp's aren't sent for
143 * icmp's) until we probe with a ttl that's at least twice the path
144 * length. I.e., rip is really only 7 hops away. A reply that
145 * returns with a ttl of 1 is a clue this problem exists.
146 * Traceroute prints a "!" after the time if the ttl is <= 1.
147 * Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or
148 * non-standard (HPUX) software, expect to see this problem
149 * frequently and/or take care picking the target host of your
152 * Other possible annotations after the time are !H, !N, !P (got a host,
153 * network or protocol unreachable, respectively), !S or !F (source
154 * route failed or fragmentation needed -- neither of these should
155 * ever occur and the associated gateway is busted if you see one). If
156 * almost all the probes result in some kind of unreachable, traceroute
157 * will give up and exit.
161 * This program must be run by root or be setuid. (I suggest that
162 * you *don't* make it setuid -- casual use could result in a lot
163 * of unnecessary traffic on our poor, congested nets.)
165 * This program requires a kernel mod that does not appear in any
166 * system available from Berkeley: A raw ip socket using proto
167 * IPPROTO_RAW must interpret the data sent as an ip datagram (as
168 * opposed to data to be wrapped in a ip datagram). See the README
169 * file that came with the source to this program for a description
170 * of the mods I made to /sys/netinet/raw_ip.c. Your mileage may
171 * vary. But, again, ANY 4.x (x < 4) BSD KERNEL WILL HAVE TO BE
172 * MODIFIED TO RUN THIS PROGRAM.
174 * The udp port usage may appear bizarre (well, ok, it is bizarre).
175 * The problem is that an icmp message only contains 8 bytes of
176 * data from the original datagram. 8 bytes is the size of a udp
177 * header so, if we want to associate replies with the original
178 * datagram, the necessary information must be encoded into the
179 * udp header (the ip id could be used but there's no way to
180 * interlock with the kernel's assignment of ip id's and, anyway,
181 * it would have taken a lot more kernel hacking to allow this
182 * code to set the ip id). So, to allow two or more users to
183 * use traceroute simultaneously, we use this task's pid as the
184 * source port (the high bit is set to move the port number out
185 * of the "likely" range). To keep track of which probe is being
186 * replied to (so times and/or hop counts don't get confused by a
187 * reply that was delayed in transit), we increment the destination
188 * port number before each probe.
190 * Don't use this as a coding example. I was trying to find a
191 * routing problem and this code sort-of popped out after 48 hours
192 * without sleep. I was amazed it ever compiled, much less ran.
194 * I stole the idea for this program from Steve Deering. Since
195 * the first release, I've learned that had I attended the right
196 * IETF working group meetings, I also could have stolen it from Guy
197 * Almes or Matt Mathis. I don't know (or care) who came up with
198 * the idea first. I envy the originators' perspicacity and I'm
199 * glad they didn't keep the idea a secret.
201 * Tim Seaver, Ken Adelman and C. Philip Wood provided bug fixes and/or
202 * enhancements to the original distribution.
204 * I've hacked up a round-trip-route version of this that works by
205 * sending a loose-source-routed udp datagram through the destination
206 * back to yourself. Unfortunately, SO many gateways botch source
207 * routing, the thing is almost worthless. Maybe one day...
209 * -- Van Jacobson (van@ee.lbl.gov)
210 * Tue Dec 20 03:50:13 PST 1988
213 //usage:#define traceroute_trivial_usage
214 //usage: "[-"IF_TRACEROUTE6("46")"FIldnrv] [-f 1ST_TTL] [-m MAXTTL] [-p PORT] [-q PROBES]\n"
215 //usage: " [-s SRC_IP] [-t TOS] [-w WAIT_SEC] [-g GATEWAY] [-i IFACE]\n"
216 //usage: " [-z PAUSE_MSEC] HOST [BYTES]"
217 //usage:#define traceroute_full_usage "\n\n"
218 //usage: "Trace the route to HOST\n"
219 //usage: IF_TRACEROUTE6(
220 //usage: "\n -4,-6 Force IP or IPv6 name resolution"
222 //usage: "\n -F Set the don't fragment bit"
223 //usage: "\n -I Use ICMP ECHO instead of UDP datagrams"
224 //usage: "\n -l Display the TTL value of the returned packet"
225 //usage: "\n -d Set SO_DEBUG options to socket"
226 //usage: "\n -n Print numeric addresses"
227 //usage: "\n -r Bypass routing tables, send directly to HOST"
228 //usage: "\n -v Verbose"
229 //usage: "\n -m Max time-to-live (max number of hops)"
230 //usage: "\n -p Base UDP port number used in probes"
231 //usage: "\n (default 33434)"
232 //usage: "\n -q Number of probes per TTL (default 3)"
233 //usage: "\n -s IP address to use as the source address"
234 //usage: "\n -t Type-of-service in probe packets (default 0)"
235 //usage: "\n -w Time in seconds to wait for a response (default 3)"
236 //usage: "\n -g Loose source route gateway (8 max)"
238 //usage:#define traceroute6_trivial_usage
239 //usage: "[-dnrv] [-m MAXTTL] [-p PORT] [-q PROBES]\n"
240 //usage: " [-s SRC_IP] [-t TOS] [-w WAIT_SEC] [-i IFACE]\n"
241 //usage: " HOST [BYTES]"
242 //usage:#define traceroute6_full_usage "\n\n"
243 //usage: "Trace the route to HOST\n"
244 //usage: "\n -d Set SO_DEBUG options to socket"
245 //usage: "\n -n Print numeric addresses"
246 //usage: "\n -r Bypass routing tables, send directly to HOST"
247 //usage: "\n -v Verbose"
248 //usage: "\n -m Max time-to-live (max number of hops)"
249 //usage: "\n -p Base UDP port number used in probes"
250 //usage: "\n (default is 33434)"
251 //usage: "\n -q Number of probes per TTL (default 3)"
252 //usage: "\n -s IP address to use as the source address"
253 //usage: "\n -t Type-of-service in probe packets (default 0)"
254 //usage: "\n -w Time in seconds to wait for a response (default 3)"
256 #define TRACEROUTE_SO_DEBUG 0
258 /* TODO: undefs were uncommented - ??! we have config system for that! */
259 /* probably ok to remove altogether */
260 //#undef CONFIG_FEATURE_TRACEROUTE_VERBOSE
261 //#define CONFIG_FEATURE_TRACEROUTE_VERBOSE
262 //#undef CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE
263 //#define CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE
264 //#undef CONFIG_FEATURE_TRACEROUTE_USE_ICMP
265 //#define CONFIG_FEATURE_TRACEROUTE_USE_ICMP
269 #include <arpa/inet.h>
270 #include <netinet/in.h>
271 #include <netinet/udp.h>
272 #include <netinet/ip.h>
273 #include <netinet/ip_icmp.h>
274 #if ENABLE_FEATURE_IPV6
275 # include <netinet/ip6.h>
276 # include <netinet/icmp6.h>
278 # define SOL_IPV6 IPPROTO_IPV6
283 #include "inet_common.h"
286 # define IPPROTO_ICMP 1
289 # define IPPROTO_IP 0
293 #define OPT_STRING "FIlnrdvxt:i:m:p:q:s:w:z:f:" \
294 IF_FEATURE_TRACEROUTE_SOURCE_ROUTE("g:") \
295 "4" IF_TRACEROUTE6("6")
297 OPT_DONT_FRAGMNT = (1 << 0), /* F */
298 OPT_USE_ICMP = (1 << 1) * ENABLE_FEATURE_TRACEROUTE_USE_ICMP, /* I */
299 OPT_TTL_FLAG = (1 << 2), /* l */
300 OPT_ADDR_NUM = (1 << 3), /* n */
301 OPT_BYPASS_ROUTE = (1 << 4), /* r */
302 OPT_DEBUG = (1 << 5), /* d */
303 OPT_VERBOSE = (1 << 6) * ENABLE_FEATURE_TRACEROUTE_VERBOSE, /* v */
304 OPT_IP_CHKSUM = (1 << 7), /* x */
305 OPT_TOS = (1 << 8), /* t */
306 OPT_DEVICE = (1 << 9), /* i */
307 OPT_MAX_TTL = (1 << 10), /* m */
308 OPT_PORT = (1 << 11), /* p */
309 OPT_NPROBES = (1 << 12), /* q */
310 OPT_SOURCE = (1 << 13), /* s */
311 OPT_WAITTIME = (1 << 14), /* w */
312 OPT_PAUSE_MS = (1 << 15), /* z */
313 OPT_FIRST_TTL = (1 << 16), /* f */
314 OPT_SOURCE_ROUTE = (1 << 17) * ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE, /* g */
315 OPT_IPV4 = (1 << (17+ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE)), /* 4 */
316 OPT_IPV6 = (1 << (18+ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE)) * ENABLE_TRACEROUTE6, /* 6 */
318 #define verbose (option_mask32 & OPT_VERBOSE)
322 rcvsock = 3, /* receive (icmp) socket file descriptor */
323 sndsock = 4, /* send (udp/icmp) socket file descriptor */
326 /* Data section of the probe packet */
328 unsigned char seq; /* sequence number of this packet */
329 unsigned char ttl; /* ttl packet left with */
330 // UNUSED. Retaining to have the same packet size.
331 struct timeval tv_UNUSED PACKED; /* time packet left */
334 #if ENABLE_TRACEROUTE6
338 struct timeval tv_UNUSED PACKED; /* time packet left */
344 struct outdata_t *outdata;
345 len_and_sockaddr *dest_lsa;
346 int packlen; /* total length of packet */
347 int pmtu; /* Path MTU Discovery (RFC1191) */
349 uint16_t port; // 32768 + 666; /* start udp dest port # for probe packets */
350 int waittime; // 5; /* time to wait for response (in seconds) */
351 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
352 int optlen; /* length of ip options */
356 unsigned char recv_pkt[512]; /* last inbound (icmp) packet */
357 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
358 /* Maximum number of gateways (include room for one noop) */
359 #define NGATEWAYS ((int)((MAX_IPOPTLEN - IPOPT_MINOFF - 1) / sizeof(uint32_t)))
360 /* loose source route gateway list (including room for final destination) */
361 uint32_t gwlist[NGATEWAYS + 1];
365 #define G (*ptr_to_globals)
366 #define outip (G.outip )
367 #define outdata (G.outdata )
368 #define dest_lsa (G.dest_lsa )
369 #define packlen (G.packlen )
370 #define pmtu (G.pmtu )
371 #define ident (G.ident )
372 #define port (G.port )
373 #define waittime (G.waittime )
374 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
375 # define optlen (G.optlen )
377 #define recv_pkt (G.recv_pkt )
378 #define gwlist (G.gwlist )
379 #define INIT_G() do { \
380 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
381 port = 32768 + 666; \
385 #define outicmp ((struct icmp *)(outip + 1))
386 #define outudp ((struct udphdr *)(outip + 1))
389 /* libbb candidate? tftp uses this idiom too */
390 static len_and_sockaddr* dup_sockaddr(const len_and_sockaddr *lsa)
392 len_and_sockaddr *new_lsa = xzalloc(LSA_LEN_SIZE + lsa->len);
393 memcpy(new_lsa, lsa, LSA_LEN_SIZE + lsa->len);
399 wait_for_reply(len_and_sockaddr *from_lsa, struct sockaddr *to, unsigned *timestamp_us, int *left_ms)
401 struct pollfd pfd[1];
405 pfd[0].events = POLLIN;
406 if (*left_ms >= 0 && safe_poll(pfd, 1, *left_ms) > 0) {
409 read_len = recv_from_to(rcvsock,
410 recv_pkt, sizeof(recv_pkt),
411 /*flags:*/ MSG_DONTWAIT,
412 &from_lsa->u.sa, to, from_lsa->len);
414 *left_ms -= (t - *timestamp_us) / 1000;
422 * Checksum routine for Internet Protocol family headers (C Version)
425 in_cksum(uint16_t *addr, int len)
433 * Our algorithm is simple, using a 32 bit accumulator (sum),
434 * we add sequential 16 bit words to it, and at the end, fold
435 * back all the carry bits from the top 16 bits into the lower
443 /* mop up an odd byte, if necessary */
445 sum += *(unsigned char *)w;
447 /* add back carry outs from top 16 bits to low 16 bits */
448 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
449 sum += (sum >> 16); /* add carry */
450 answer = ~sum; /* truncate to 16 bits */
455 send_probe(int seq, int ttl)
461 #if ENABLE_TRACEROUTE6
462 if (dest_lsa->u.sa.sa_family == AF_INET6) {
463 struct outdata6_t *pkt = (struct outdata6_t *) outip;
464 pkt->ident6 = htonl(ident);
465 pkt->seq6 = htonl(seq);
466 /*gettimeofday(&pkt->tv, &tz);*/
472 // UNUSED: was storing gettimeofday's result there, but never ever checked it
473 /*memcpy(&outdata->tv, tp, sizeof(outdata->tv));*/
475 if (option_mask32 & OPT_USE_ICMP) {
476 outicmp->icmp_seq = htons(seq);
478 /* Always calculate checksum for icmp packets */
479 outicmp->icmp_cksum = 0;
480 outicmp->icmp_cksum = in_cksum((uint16_t *)outicmp,
481 packlen - (sizeof(*outip) + optlen));
482 if (outicmp->icmp_cksum == 0)
483 outicmp->icmp_cksum = 0xffff;
487 //BUG! verbose is (x & OPT_VERBOSE), not a counter!
488 #if 0 //ENABLE_FEATURE_TRACEROUTE_VERBOSE
489 /* XXX undocumented debugging hack */
494 sp = (uint16_t *)outip;
495 nshorts = (unsigned)packlen / sizeof(uint16_t);
497 printf("[ %d bytes", packlen);
498 while (--nshorts >= 0) {
501 printf(" %04x", ntohs(*sp));
507 printf(" %02x", *(unsigned char *)sp);
513 #if ENABLE_TRACEROUTE6
514 if (dest_lsa->u.sa.sa_family == AF_INET6) {
515 res = setsockopt(sndsock, SOL_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
517 bb_perror_msg_and_die("setsockopt UNICAST_HOPS %d", ttl);
524 res = setsockopt(sndsock, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
526 bb_perror_msg_and_die("setsockopt ttl %d", ttl);
529 len = packlen - sizeof(*outip);
530 if (!(option_mask32 & OPT_USE_ICMP)) {
532 len -= sizeof(*outudp);
533 set_nport(&dest_lsa->u.sa, htons(port + seq));
537 res = xsendto(sndsock, out, len, &dest_lsa->u.sa, dest_lsa->len);
539 bb_info_msg("sent %d octets, ret=%d", len, res);
542 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
544 * Convert an ICMP "type" field to a printable string.
547 pr_type(unsigned char t)
549 static const char *const ttab[] = {
550 "Echo Reply", "ICMP 1", "ICMP 2", "Dest Unreachable",
551 "Source Quench", "Redirect", "ICMP 6", "ICMP 7",
552 "Echo", "Router Advert", "Router Solicit", "Time Exceeded",
553 "Param Problem", "Timestamp", "Timestamp Reply", "Info Request",
554 "Info Reply", "Mask Request", "Mask Reply"
556 # if ENABLE_TRACEROUTE6
557 static const char *const ttab6[] = {
558 [0] "Error", "Dest Unreachable", "Packet Too Big", "Time Exceeded",
560 [8] "Echo Request", "Echo Reply", "Membership Query", "Membership Report",
561 [12] "Membership Reduction", "Router Solicit", "Router Advert", "Neighbor Solicit",
562 [16] "Neighbor Advert", "Redirect",
565 if (dest_lsa->u.sa.sa_family == AF_INET6) {
568 if (t < 128 || t > ND_REDIRECT)
569 return "OUT-OF-RANGE";
570 return ttab6[(t & 63) + 8];
573 if (t >= ARRAY_SIZE(ttab))
574 return "OUT-OF-RANGE";
580 #if !ENABLE_FEATURE_TRACEROUTE_VERBOSE
581 #define packet4_ok(read_len, from, seq) \
582 packet4_ok(read_len, seq)
585 packet4_ok(int read_len, const struct sockaddr_in *from, int seq)
587 const struct icmp *icp;
588 unsigned char type, code;
592 ip = (struct ip *) recv_pkt;
593 hlen = ip->ip_hl << 2;
594 if (read_len < hlen + ICMP_MINLEN) {
595 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
597 printf("packet too short (%d bytes) from %s\n", read_len,
598 inet_ntoa(from->sin_addr));
603 icp = (struct icmp *)(recv_pkt + hlen);
604 type = icp->icmp_type;
605 code = icp->icmp_code;
606 /* Path MTU Discovery (RFC1191) */
608 if (code == ICMP_UNREACH_NEEDFRAG)
609 pmtu = ntohs(icp->icmp_nextmtu);
611 if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS)
612 || type == ICMP_UNREACH
613 || type == ICMP_ECHOREPLY
615 const struct ip *hip;
616 const struct udphdr *up;
619 hlen = hip->ip_hl << 2;
620 if (option_mask32 & OPT_USE_ICMP) {
624 if (type == ICMP_ECHOREPLY
625 && icp->icmp_id == htons(ident)
626 && icp->icmp_seq == htons(seq)
628 return ICMP_UNREACH_PORT+1;
631 hicmp = (struct icmp *)((unsigned char *)hip + hlen);
632 if (hlen + SIZEOF_ICMP_HDR <= read_len
633 && hip->ip_p == IPPROTO_ICMP
634 && hicmp->icmp_id == htons(ident)
635 && hicmp->icmp_seq == htons(seq)
637 return (type == ICMP_TIMXCEED ? -1 : code + 1);
640 up = (struct udphdr *)((char *)hip + hlen);
641 if (hlen + 12 <= read_len
642 && hip->ip_p == IPPROTO_UDP
643 // Off: since we do not form the entire IP packet,
644 // but defer it to kernel, we can't set source port,
645 // and thus can't check it here in the reply
646 /* && up->source == htons(ident) */
647 && up->dest == htons(port + seq)
649 return (type == ICMP_TIMXCEED ? -1 : code + 1);
653 #if ENABLE_FEATURE_TRACEROUTE_VERBOSE
656 uint32_t *lp = (uint32_t *)&icp->icmp_ip;
658 printf("\n%d bytes from %s to "
659 "%s: icmp type %d (%s) code %d\n",
660 read_len, inet_ntoa(from->sin_addr),
661 inet_ntoa(ip->ip_dst),
662 type, pr_type(type), icp->icmp_code);
663 for (i = 4; i < read_len; i += sizeof(*lp))
664 printf("%2d: x%8.8x\n", i, *lp++);
670 #if ENABLE_TRACEROUTE6
671 # if !ENABLE_FEATURE_TRACEROUTE_VERBOSE
672 #define packet_ok(read_len, from_lsa, to, seq) \
673 packet_ok(read_len, from_lsa, seq)
676 packet_ok(int read_len, len_and_sockaddr *from_lsa,
680 const struct icmp6_hdr *icp;
681 unsigned char type, code;
683 if (from_lsa->u.sa.sa_family == AF_INET)
684 return packet4_ok(read_len, &from_lsa->u.sin, seq);
686 icp = (struct icmp6_hdr *) recv_pkt;
688 type = icp->icmp6_type;
689 code = icp->icmp6_code;
691 if ((type == ICMP6_TIME_EXCEEDED && code == ICMP6_TIME_EXCEED_TRANSIT)
692 || type == ICMP6_DST_UNREACH
698 hip = (struct ip6_hdr *)(icp + 1);
699 up = (struct udphdr *) (hip + 1);
700 nexthdr = hip->ip6_nxt;
702 if (nexthdr == IPPROTO_FRAGMENT) {
703 nexthdr = *(unsigned char*)up;
706 if (nexthdr == IPPROTO_UDP) {
707 struct outdata6_t *pkt;
709 pkt = (struct outdata6_t *) (up + 1);
711 if (ntohl(pkt->ident6) == ident
712 && ntohl(pkt->seq6) == seq
714 return (type == ICMP6_TIME_EXCEEDED ? -1 : (code<<8)+1);
719 # if ENABLE_FEATURE_TRACEROUTE_VERBOSE
722 char pa1[MAXHOSTNAMELEN];
723 char pa2[MAXHOSTNAMELEN];
726 p = (unsigned char *) (icp + 1);
728 printf("\n%d bytes from %s to "
729 "%s: icmp type %d (%s) code %d\n",
731 inet_ntop(AF_INET6, &from_lsa->u.sin6.sin6_addr, pa1, sizeof(pa1)),
732 inet_ntop(AF_INET6, &((struct sockaddr_in6*)to)->sin6_addr, pa2, sizeof(pa2)),
733 type, pr_type(type), icp->icmp6_code);
735 read_len -= sizeof(struct icmp6_hdr);
736 for (i = 0; i < read_len; i++) {
741 printf("%02x", p[i]);
742 if ((i % 16 == 15) && (i + 1 < read_len))
751 #else /* !ENABLE_TRACEROUTE6 */
752 static ALWAYS_INLINE int
753 packet_ok(int read_len,
754 len_and_sockaddr *from_lsa IF_NOT_FEATURE_TRACEROUTE_VERBOSE(UNUSED_PARAM),
755 struct sockaddr *to UNUSED_PARAM,
758 return packet4_ok(read_len, &from_lsa->u.sin, seq);
763 * Construct an Internet address representation.
764 * If the -n flag has been supplied, give
765 * numeric value, otherwise try for symbolic name.
768 print_inetname(const struct sockaddr *from)
770 char *ina = xmalloc_sockaddr2dotted_noport(from);
772 if (option_mask32 & OPT_ADDR_NUM) {
777 if (from->sa_family != AF_INET
778 || ((struct sockaddr_in*)from)->sin_addr.s_addr != INADDR_ANY
780 /* Try to reverse resolve if it is not 0.0.0.0 */
781 n = xmalloc_sockaddr2host_noport((struct sockaddr*)from);
783 printf(" %s (%s)", (n ? n : ina), ina);
790 print(int read_len, const struct sockaddr *from, const struct sockaddr *to)
792 print_inetname(from);
795 char *ina = xmalloc_sockaddr2dotted_noport(to);
796 #if ENABLE_TRACEROUTE6
797 if (to->sa_family == AF_INET6) {
798 read_len -= sizeof(struct ip6_hdr);
802 struct ip *ip4packet = (struct ip*)recv_pkt;
803 read_len -= ip4packet->ip_hl << 2;
805 printf(" %d bytes to %s", read_len, ina);
811 print_delta_ms(unsigned t1p, unsigned t2p)
813 unsigned tt = t2p - t1p;
814 printf(" %u.%03u ms", tt / 1000, tt % 1000);
818 * Usage: [-dFIlnrvx] [-g gateway] [-i iface] [-f first_ttl]
819 * [-m max_ttl] [ -p port] [-q nqueries] [-s src_addr] [-t tos]
820 * [-w waittime] [-z pausemsecs] host [packetlen]"
823 common_traceroute_main(int op, char **argv)
830 unsigned pausemsecs = 0;
838 char *pausemsecs_str;
840 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
841 llist_t *source_route_list = NULL;
844 #if ENABLE_TRACEROUTE6
847 enum { af = AF_INET };
851 len_and_sockaddr *from_lsa;
852 struct sockaddr *lastaddr;
858 opt_complementary = "-1:x-x" IF_FEATURE_TRACEROUTE_SOURCE_ROUTE(":g::");
859 op |= getopt32(argv, OPT_STRING
860 , &tos_str, &device, &max_ttl_str, &port_str, &nprobes_str
861 , &source, &waittime_str, &pausemsecs_str, &first_ttl_str
862 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
869 if (op & OPT_IP_CHKSUM)
870 bb_error_msg("warning: ip checksums disabled");
873 tos = xatou_range(tos_str, 0, 255);
874 if (op & OPT_MAX_TTL)
875 max_ttl = xatou_range(max_ttl_str, 1, 255);
877 port = xatou16(port_str);
878 if (op & OPT_NPROBES)
879 nprobes = xatou_range(nprobes_str, 1, INT_MAX);
880 if (op & OPT_SOURCE) {
882 * set the ip source address of the outbound
883 * probe (e.g., on a multi-homed host).
886 bb_error_msg_and_die(bb_msg_you_must_be_root);
888 if (op & OPT_WAITTIME)
889 waittime = xatou_range(waittime_str, 1, 24 * 60 * 60);
890 if (op & OPT_PAUSE_MS)
891 pausemsecs = xatou_range(pausemsecs_str, 0, 60 * 60 * 1000);
892 if (op & OPT_FIRST_TTL)
893 first_ttl = xatou_range(first_ttl_str, 1, max_ttl);
895 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE
896 if (source_route_list) {
897 while (source_route_list) {
898 len_and_sockaddr *lsa;
900 if (lsrr >= NGATEWAYS)
901 bb_error_msg_and_die("no more than %d gateways", NGATEWAYS);
902 lsa = xhost_and_af2sockaddr(llist_pop(&source_route_list), 0, AF_INET);
903 gwlist[lsrr] = lsa->u.sin.sin_addr.s_addr;
907 optlen = (lsrr + 1) * sizeof(gwlist[0]);
911 /* Process destination and optional packet size */
912 minpacket = sizeof(*outip) + SIZEOF_ICMP_HDR + sizeof(*outdata) + optlen;
913 if (!(op & OPT_USE_ICMP))
914 minpacket += sizeof(*outudp) - SIZEOF_ICMP_HDR;
915 #if ENABLE_TRACEROUTE6
921 dest_lsa = xhost_and_af2sockaddr(argv[0], port, af);
922 af = dest_lsa->u.sa.sa_family;
924 minpacket = sizeof(struct outdata6_t);
926 dest_lsa = xhost2sockaddr(argv[0], port);
930 packlen = xatoul_range(argv[1], minpacket, 32 * 1024);
932 /* Ensure the socket fds won't be 0, 1 or 2 */
935 #if ENABLE_TRACEROUTE6
936 if (af == AF_INET6) {
937 xmove_fd(xsocket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6), rcvsock);
938 # ifdef IPV6_RECVPKTINFO
939 setsockopt(rcvsock, SOL_IPV6, IPV6_RECVPKTINFO,
940 &const_int_1, sizeof(const_int_1));
941 setsockopt(rcvsock, SOL_IPV6, IPV6_2292PKTINFO,
942 &const_int_1, sizeof(const_int_1));
944 setsockopt(rcvsock, SOL_IPV6, IPV6_PKTINFO,
945 &const_int_1, sizeof(const_int_1));
950 xmove_fd(xsocket(AF_INET, SOCK_RAW, IPPROTO_ICMP), rcvsock);
953 #if TRACEROUTE_SO_DEBUG
955 setsockopt(rcvsock, SOL_SOCKET, SO_DEBUG,
956 &const_int_1, sizeof(const_int_1));
958 if (op & OPT_BYPASS_ROUTE)
959 setsockopt(rcvsock, SOL_SOCKET, SO_DONTROUTE,
960 &const_int_1, sizeof(const_int_1));
962 #if ENABLE_TRACEROUTE6
963 if (af == AF_INET6) {
964 static const int two = 2;
965 if (setsockopt(rcvsock, SOL_RAW, IPV6_CHECKSUM, &two, sizeof(two)) < 0)
966 bb_perror_msg_and_die("setsockopt RAW_CHECKSUM");
967 xmove_fd(xsocket(af, SOCK_DGRAM, 0), sndsock);
971 if (op & OPT_USE_ICMP)
972 xmove_fd(xsocket(AF_INET, SOCK_RAW, IPPROTO_ICMP), sndsock);
974 xmove_fd(xsocket(AF_INET, SOCK_DGRAM, 0), sndsock);
975 #if ENABLE_FEATURE_TRACEROUTE_SOURCE_ROUTE && defined IP_OPTIONS
977 unsigned char optlist[MAX_IPOPTLEN];
981 gwlist[lsrr] = dest_lsa->u.sin.sin_addr.s_addr;
984 /* force 4 byte alignment */
985 optlist[0] = IPOPT_NOP;
986 /* loose source route option */
987 optlist[1] = IPOPT_LSRR;
988 size = lsrr * sizeof(gwlist[0]);
989 optlist[2] = size + 3;
990 /* pointer to LSRR addresses */
991 optlist[3] = IPOPT_MINOFF;
992 memcpy(optlist + 4, gwlist, size);
994 if (setsockopt(sndsock, IPPROTO_IP, IP_OPTIONS,
995 (char *)optlist, size + sizeof(gwlist[0])) < 0) {
996 bb_perror_msg_and_die("IP_OPTIONS");
1003 if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, &packlen, sizeof(packlen)) < 0) {
1004 bb_perror_msg_and_die("SO_SNDBUF");
1008 if ((op & OPT_TOS) && setsockopt(sndsock, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) {
1009 bb_perror_msg_and_die("setsockopt tos %d", tos);
1013 if (op & OPT_DONT_FRAGMNT)
1014 setsockopt(sndsock, IPPROTO_IP, IP_DONTFRAG,
1015 &const_int_1, sizeof(const_int_1));
1017 #if TRACEROUTE_SO_DEBUG
1019 setsockopt(sndsock, SOL_SOCKET, SO_DEBUG,
1020 &const_int_1, sizeof(const_int_1));
1022 if (op & OPT_BYPASS_ROUTE)
1023 setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE,
1024 &const_int_1, sizeof(const_int_1));
1026 outip = xzalloc(packlen);
1030 if (af == AF_INET) {
1031 if (op & OPT_USE_ICMP) {
1033 outicmp->icmp_type = ICMP_ECHO;
1034 outicmp->icmp_id = htons(ident);
1035 outdata = (struct outdata_t *)((char *)outicmp + SIZEOF_ICMP_HDR);
1037 outdata = (struct outdata_t *)(outudp + 1);
1041 if (op & OPT_DEVICE) /* hmm, do we need error check? */
1042 setsockopt_bindtodevice(sndsock, device);
1044 if (op & OPT_SOURCE) {
1045 #if ENABLE_TRACEROUTE6
1046 // TODO: need xdotted_and_af2sockaddr?
1047 len_and_sockaddr *source_lsa = xhost_and_af2sockaddr(source, 0, af);
1049 len_and_sockaddr *source_lsa = xdotted2sockaddr(source, 0);
1051 /* Ping4 does this (why?) */
1053 if (setsockopt(sndsock, IPPROTO_IP, IP_MULTICAST_IF,
1054 &source_lsa->u.sa, source_lsa->len))
1055 bb_error_msg_and_die("can't set multicast source interface");
1056 //TODO: we can query source port we bound to,
1057 // and check it in replies... if we care enough
1058 xbind(sndsock, &source_lsa->u.sa, source_lsa->len);
1061 #if ENABLE_TRACEROUTE6
1062 else if (af == AF_INET6) {
1063 //TODO: why we don't do it for IPv4?
1064 len_and_sockaddr *source_lsa;
1066 int probe_fd = xsocket(af, SOCK_DGRAM, 0);
1067 if (op & OPT_DEVICE)
1068 setsockopt_bindtodevice(probe_fd, device);
1069 set_nport(&dest_lsa->u.sa, htons(1025));
1070 /* dummy connect. makes kernel pick source IP (and port) */
1071 xconnect(probe_fd, &dest_lsa->u.sa, dest_lsa->len);
1072 set_nport(&dest_lsa->u.sa, htons(port));
1074 /* read IP and port */
1075 source_lsa = get_sock_lsa(probe_fd);
1076 if (source_lsa == NULL)
1077 bb_error_msg_and_die("can't get probe addr");
1081 /* bind our sockets to this IP (but not port) */
1082 set_nport(&source_lsa->u.sa, 0);
1083 xbind(sndsock, &source_lsa->u.sa, source_lsa->len);
1084 xbind(rcvsock, &source_lsa->u.sa, source_lsa->len);
1090 /* Revert to non-privileged user after opening sockets */
1094 printf("traceroute to %s (%s)", argv[0],
1095 xmalloc_sockaddr2dotted_noport(&dest_lsa->u.sa));
1096 if (op & OPT_SOURCE)
1097 printf(" from %s", source);
1098 printf(", %d hops max, %d byte packets\n", max_ttl, packlen);
1100 from_lsa = dup_sockaddr(dest_lsa);
1101 lastaddr = xzalloc(dest_lsa->len);
1102 to = xzalloc(dest_lsa->len);
1104 for (ttl = first_ttl; ttl <= max_ttl; ++ttl) {
1106 int unreachable = 0; /* counter */
1107 int gotlastaddr = 0; /* flags */
1111 for (probe = 0; probe < nprobes; ++probe) {
1119 if (probe != 0 && pausemsecs > 0)
1120 usleep(pausemsecs * 1000);
1122 send_probe(++seq, ttl);
1123 t2 = t1 = monotonic_us();
1125 left_ms = waittime * 1000;
1126 while ((read_len = wait_for_reply(from_lsa, to, &t2, &left_ms)) != 0) {
1129 /* Recv'ed a packet, or read error */
1130 /* t2 = monotonic_us() - set by wait_for_reply */
1134 icmp_code = packet_ok(read_len, from_lsa, to, seq);
1135 /* Skip short packet */
1140 || (memcmp(lastaddr, &from_lsa->u.sa, from_lsa->len) != 0)
1142 print(read_len, &from_lsa->u.sa, to);
1143 memcpy(lastaddr, &from_lsa->u.sa, from_lsa->len);
1147 print_delta_ms(t1, t2);
1148 ip = (struct ip *)recv_pkt;
1150 if (from_lsa->u.sa.sa_family == AF_INET)
1151 if (op & OPT_TTL_FLAG)
1152 printf(" (%d)", ip->ip_ttl);
1154 /* time exceeded in transit */
1155 if (icmp_code == -1)
1158 switch (icmp_code) {
1159 #if ENABLE_TRACEROUTE6
1160 case ICMP6_DST_UNREACH_NOPORT << 8:
1164 case ICMP_UNREACH_PORT:
1165 if (ip->ip_ttl <= 1)
1170 case ICMP_UNREACH_NET:
1171 #if ENABLE_TRACEROUTE6 && (ICMP6_DST_UNREACH_NOROUTE != ICMP_UNREACH_NET)
1172 case ICMP6_DST_UNREACH_NOROUTE << 8:
1177 case ICMP_UNREACH_HOST:
1178 #if ENABLE_TRACEROUTE6
1179 case ICMP6_DST_UNREACH_ADDR << 8:
1184 case ICMP_UNREACH_PROTOCOL:
1188 case ICMP_UNREACH_NEEDFRAG:
1189 printf(" !F-%d", pmtu);
1192 case ICMP_UNREACH_SRCFAIL:
1193 #if ENABLE_TRACEROUTE6
1194 case ICMP6_DST_UNREACH_ADMIN << 8:
1199 case ICMP_UNREACH_FILTER_PROHIB:
1200 case ICMP_UNREACH_NET_PROHIB: /* misuse */
1204 case ICMP_UNREACH_HOST_PROHIB:
1208 case ICMP_UNREACH_HOST_PRECEDENCE:
1212 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
1216 case ICMP_UNREACH_NET_UNKNOWN:
1217 case ICMP_UNREACH_HOST_UNKNOWN:
1221 case ICMP_UNREACH_ISOLATED:
1225 case ICMP_UNREACH_TOSNET:
1226 case ICMP_UNREACH_TOSHOST:
1231 printf(" !<%d>", icmp_code);
1236 } /* while (wait and read a packet) */
1238 /* there was no packet at all? */
1241 } /* for (nprobes) */
1245 || (unreachable > 0 && unreachable >= nprobes - 1)
1254 int traceroute_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1255 int traceroute_main(int argc UNUSED_PARAM, char **argv)
1257 return common_traceroute_main(0, argv);
1260 #if ENABLE_TRACEROUTE6
1261 int traceroute6_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1262 int traceroute6_main(int argc UNUSED_PARAM, char **argv)
1264 return common_traceroute_main(OPT_IPV6, argv);