Commit | Line | Data |
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c64d8cd5 MW |
1 | /* -*-c-*- |
2 | * | |
3 | * Report MTU on path to specified host | |
4 | * | |
5 | * (c) 2008 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
10 | * This file is part of Trivial IP Encryption (TrIPE). | |
11 | * | |
11ad66c2 MW |
12 | * TrIPE is free software: you can redistribute it and/or modify it under |
13 | * the terms of the GNU General Public License as published by the Free | |
14 | * Software Foundation; either version 3 of the License, or (at your | |
15 | * option) any later version. | |
c64d8cd5 | 16 | * |
11ad66c2 MW |
17 | * TrIPE is distributed in the hope that it will be useful, but WITHOUT |
18 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
19 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
20 | * for more details. | |
c64d8cd5 MW |
21 | * |
22 | * You should have received a copy of the GNU General Public License | |
11ad66c2 | 23 | * along with TrIPE. If not, see <https://www.gnu.org/licenses/>. |
c64d8cd5 MW |
24 | */ |
25 | ||
26 | /*----- Header files ------------------------------------------------------*/ | |
27 | ||
28 | #include "config.h" | |
29 | ||
d245350a | 30 | #include <assert.h> |
c64d8cd5 | 31 | #include <errno.h> |
88510d86 | 32 | #include <stddef.h> |
c64d8cd5 MW |
33 | #include <stdio.h> |
34 | #include <stdlib.h> | |
35 | #include <string.h> | |
36 | #include <time.h> | |
37 | ||
38 | #include <sys/types.h> | |
39 | #include <sys/time.h> | |
40 | #include <unistd.h> | |
41 | ||
42 | #include <sys/socket.h> | |
43 | #include <netinet/in.h> | |
44 | #include <arpa/inet.h> | |
45 | #include <netdb.h> | |
46 | ||
88510d86 MW |
47 | #include <netinet/in_systm.h> |
48 | #include <netinet/ip.h> | |
49 | #include <netinet/ip_icmp.h> | |
102fa2f0 MW |
50 | #include <netinet/ip6.h> |
51 | #include <netinet/icmp6.h> | |
88510d86 MW |
52 | #include <netinet/udp.h> |
53 | ||
85ccca5f MW |
54 | #ifdef HAVE_GETIFADDRS |
55 | # include <net/if.h> | |
56 | # include <ifaddrs.h> | |
57 | # include <sys/ioctl.h> | |
58 | #endif | |
88510d86 MW |
59 | |
60 | #include <mLib/alloc.h> | |
61 | #include <mLib/bits.h> | |
c64d8cd5 MW |
62 | #include <mLib/dstr.h> |
63 | #include <mLib/hex.h> | |
64 | #include <mLib/mdwopt.h> | |
65 | #include <mLib/quis.h> | |
66 | #include <mLib/report.h> | |
67 | #include <mLib/tv.h> | |
68 | ||
69 | /*----- Static variables --------------------------------------------------*/ | |
70 | ||
71 | static unsigned char buf[65536]; | |
72 | ||
88510d86 MW |
73 | #define POLY 0x1002d |
74 | ||
c64d8cd5 MW |
75 | /*----- Utility functions -------------------------------------------------*/ |
76 | ||
88510d86 MW |
77 | /* Step a value according to a simple LFSR. */ |
78 | #define STEP(q) \ | |
79 | do (q) = ((q) & 0x8000) ? ((q) << 1) ^ POLY : ((q) << 1); while (0) | |
80 | ||
c64d8cd5 MW |
81 | /* Fill buffer with a constant but pseudorandom string. Uses a simple |
82 | * LFSR. | |
83 | */ | |
84 | static void fillbuffer(unsigned char *p, size_t sz) | |
85 | { | |
86 | unsigned int y = 0xbc20; | |
87 | const unsigned char *l = p + sz; | |
88 | int i; | |
c64d8cd5 MW |
89 | |
90 | while (p < l) { | |
91 | *p++ = y & 0xff; | |
88510d86 | 92 | for (i = 0; i < 8; i++) STEP(y); |
c64d8cd5 MW |
93 | } |
94 | } | |
95 | ||
88510d86 MW |
96 | /* Convert a string to floating point. */ |
97 | static double s2f(const char *s, const char *what) | |
98 | { | |
99 | double f; | |
100 | char *q; | |
c64d8cd5 | 101 | |
88510d86 MW |
102 | errno = 0; |
103 | f = strtod(s, &q); | |
104 | if (errno || *q) die(EXIT_FAILURE, "bad %s", what); | |
105 | return (f); | |
106 | } | |
c64d8cd5 | 107 | |
88510d86 MW |
108 | /* Convert a floating-point value into a struct timeval. */ |
109 | static void f2tv(struct timeval *tv, double t) | |
110 | { tv->tv_sec = t; tv->tv_usec = (t - tv->tv_sec)*MILLION; } | |
111 | ||
454f5a1a MW |
112 | union addr { |
113 | struct sockaddr sa; | |
114 | struct sockaddr_in sin; | |
22062fb6 | 115 | struct sockaddr_in6 sin6; |
454f5a1a MW |
116 | }; |
117 | ||
22062fb6 MW |
118 | /* Check whether an address family is even slightly supported. */ |
119 | static int addrfamok(int af) | |
120 | { | |
121 | switch (af) { | |
122 | case AF_INET: case AF_INET6: return (1); | |
123 | default: return (0); | |
124 | } | |
125 | } | |
126 | ||
454f5a1a MW |
127 | /* Return the size of a socket address. */ |
128 | static size_t addrsz(const union addr *a) | |
129 | { | |
130 | switch (a->sa.sa_family) { | |
131 | case AF_INET: return (sizeof(a->sin)); | |
22062fb6 | 132 | case AF_INET6: return (sizeof(a->sin6)); |
454f5a1a MW |
133 | default: abort(); |
134 | } | |
135 | } | |
136 | ||
88510d86 MW |
137 | /*----- Main algorithm skeleton -------------------------------------------*/ |
138 | ||
139 | struct param { | |
140 | unsigned f; /* Various flags */ | |
141 | #define F_VERBOSE 1u /* Give a running commentary */ | |
142 | double retx; /* Initial retransmit interval */ | |
143 | double regr; /* Retransmit growth factor */ | |
144 | double timeout; /* Retransmission timeout */ | |
145 | int seqoff; /* Offset to write sequence number */ | |
146 | const struct probe_ops *pops; /* Probe algorithm description */ | |
454f5a1a | 147 | union addr a; /* Destination address */ |
88510d86 MW |
148 | }; |
149 | ||
150 | struct probestate { | |
151 | const struct param *pp; | |
152 | unsigned q; | |
153 | }; | |
154 | ||
155 | struct probe_ops { | |
156 | const char *name; | |
157 | const struct probe_ops *next; | |
158 | size_t statesz; | |
159 | int (*setup)(void *, int, const struct param *); | |
160 | void (*finish)(void *); | |
161 | void (*selprep)(void *, int *, fd_set *); | |
162 | int (*xmit)(void *, int); | |
163 | int (*selproc)(void *, fd_set *, struct probestate *); | |
164 | }; | |
165 | ||
166 | #define OPS_CHAIN 0 | |
167 | ||
168 | enum { | |
169 | RC_FAIL = -99, | |
170 | RC_OK = 0, | |
171 | RC_LOWER = -1, | |
172 | RC_HIGHER = -2, | |
173 | RC_NOREPLY = -3 | |
174 | /* or a positive MTU upper-bound */ | |
175 | }; | |
176 | ||
177 | /* Add a file descriptor FD to the set `fd_in', updating `*maxfd'. */ | |
178 | #define ADDFD(fd) \ | |
179 | do { FD_SET(fd, fd_in); if (*maxfd < fd) *maxfd = fd; } while (0) | |
180 | ||
181 | /* Check whether a buffer contains a packet from our current probe. */ | |
182 | static int mypacketp(struct probestate *ps, | |
183 | const unsigned char *p, size_t sz) | |
184 | { | |
185 | const struct param *pp = ps->pp; | |
c64d8cd5 | 186 | |
88510d86 MW |
187 | return (sz >= pp->seqoff + 2 && LOAD16(p + pp->seqoff) == ps->q); |
188 | } | |
189 | ||
190 | /* See whether MTU is an acceptable MTU value. Return an appropriate | |
191 | * RC_... code or a new suggested MTU. | |
192 | */ | |
193 | static int probe(struct probestate *ps, void *st, int mtu) | |
c64d8cd5 | 194 | { |
88510d86 | 195 | const struct param *pp = ps->pp; |
c64d8cd5 | 196 | fd_set fd_in; |
88510d86 MW |
197 | struct timeval tv, now, when, done; |
198 | double timer = pp->retx; | |
199 | int rc, maxfd; | |
200 | ||
201 | /* Set up the first retransmit and give-up timers. */ | |
202 | gettimeofday(&now, 0); | |
203 | f2tv(&tv, pp->timeout); TV_ADD(&done, &now, &tv); | |
204 | f2tv(&tv, timer); TV_ADD(&when, &now, &tv); | |
205 | if (TV_CMP(&when, >, &done)) when = done; | |
206 | ||
207 | /* Send the initial probe. */ | |
208 | if (pp->f & F_VERBOSE) | |
209 | moan("sending probe of size %d (seq = %04x)", mtu, ps->q); | |
210 | STEP(ps->q); | |
211 | STORE16(buf + pp->seqoff, ps->q); | |
212 | if ((rc = pp->pops->xmit(st, mtu)) != RC_OK) return (rc); | |
213 | ||
214 | for (;;) { | |
215 | ||
216 | /* Wait for something interesting to happen. */ | |
217 | maxfd = 0; FD_ZERO(&fd_in); | |
218 | pp->pops->selprep(st, &maxfd, &fd_in); | |
219 | TV_SUB(&tv, &when, &now); | |
220 | if (select(maxfd + 1, &fd_in, 0, 0, &tv) < 0) return (RC_FAIL); | |
221 | gettimeofday(&now, 0); | |
222 | ||
223 | /* See whether the probe method has any answers for us. */ | |
224 | if ((rc = pp->pops->selproc(st, &fd_in, ps)) != RC_OK) return (rc); | |
225 | ||
226 | /* If we've waited too long, give up. If we should retransmit, do | |
227 | * that. | |
228 | */ | |
229 | if (TV_CMP(&now, >, &done)) | |
230 | return (RC_NOREPLY); | |
231 | else if (TV_CMP(&now, >, &when)) { | |
232 | if (pp->f & F_VERBOSE) moan("re-sending probe of size %d", mtu); | |
233 | if ((rc = pp->pops->xmit(st, mtu)) != RC_OK) return (rc); | |
234 | do { | |
235 | timer *= pp->regr; f2tv(&tv, timer); TV_ADD(&when, &when, &tv); | |
236 | } while (TV_CMP(&when, <, &now)); | |
237 | if (TV_CMP(&when, >, &done)) when = done; | |
238 | } | |
239 | } | |
240 | } | |
c64d8cd5 | 241 | |
88510d86 MW |
242 | /* Discover the path MTU to the destination address. */ |
243 | static int pathmtu(const struct param *pp) | |
244 | { | |
245 | int sk; | |
246 | int mtu, lo, hi; | |
247 | int rc, droppy = -1; | |
248 | void *st; | |
249 | struct probestate ps; | |
250 | ||
251 | /* Build and connect a UDP socket. We'll need this to know the local port | |
252 | * number to use if nothing else. Set other stuff up. | |
253 | */ | |
454f5a1a MW |
254 | if ((sk = socket(pp->a.sa.sa_family, SOCK_DGRAM, IPPROTO_UDP)) < 0) |
255 | goto fail_0; | |
256 | if (connect(sk, &pp->a.sa, addrsz(&pp->a))) goto fail_1; | |
88510d86 MW |
257 | st = xmalloc(pp->pops->statesz); |
258 | if ((mtu = pp->pops->setup(st, sk, pp)) < 0) goto fail_2; | |
259 | ps.pp = pp; ps.q = rand() & 0xffff; | |
22062fb6 MW |
260 | switch (pp->a.sa.sa_family) { |
261 | case AF_INET: lo = 576; break; | |
262 | case AF_INET6: lo = 1280; break; | |
263 | default: abort(); | |
264 | } | |
265 | hi = mtu; | |
266 | if (hi < lo) { errno = EMSGSIZE; return (-1); } | |
88510d86 MW |
267 | |
268 | /* And now we do a thing which is sort of like a binary search, except that | |
269 | * we also take explicit clues as establishing a new upper bound, and we | |
270 | * try to hug that initially. | |
271 | */ | |
c64d8cd5 | 272 | for (;;) { |
d245350a MW |
273 | assert(lo <= mtu && mtu <= hi); |
274 | if (pp->f & F_VERBOSE) moan("probe: %d <= %d <= %d", lo, mtu, hi); | |
88510d86 MW |
275 | rc = probe(&ps, st, mtu); |
276 | switch (rc) { | |
277 | ||
278 | case RC_FAIL: | |
279 | if (pp->f & F_VERBOSE) moan("probe failed"); | |
280 | goto fail_3; | |
281 | ||
282 | case RC_NOREPLY: | |
283 | /* If we've not seen a dropped packet before then we don't know what | |
284 | * this means yet -- in particular, we don't know which bit of the | |
285 | * network is swallowing packets. Send a minimum-size probe. If | |
286 | * that doesn't come back then assume that the remote host is | |
287 | * swallowing our packets. If it does, then we assume that dropped | |
288 | * packets are a result of ICMP fragmentation-needed reports being | |
289 | * lost or suppressed. | |
290 | */ | |
291 | if (pp->f & F_VERBOSE) moan("gave up: black hole detected"); | |
292 | if (droppy == -1) { | |
293 | if (pp->f & F_VERBOSE) moan("sending minimum-size probe"); | |
294 | switch (probe(&ps, st, lo)) { | |
295 | case RC_FAIL: | |
296 | goto fail_3; | |
297 | case RC_NOREPLY: | |
298 | if (pp->f & F_VERBOSE) { | |
299 | moan("no reply from min-size probe: " | |
300 | "assume black hole at target"); | |
301 | } | |
302 | droppy = 1; | |
303 | break; | |
304 | case RC_HIGHER: | |
305 | if (pp->f & F_VERBOSE) { | |
306 | moan("reply from min-size probe OK: " | |
307 | "assume black hole in network"); | |
308 | } | |
309 | droppy = 0; | |
310 | break; | |
311 | default: | |
312 | if (pp->f & F_VERBOSE) | |
313 | moan("unexpected return code from probe"); | |
314 | errno = ENOTCONN; | |
315 | goto fail_3; | |
316 | } | |
317 | } | |
318 | ||
319 | if (droppy) goto higher; else goto lower; | |
320 | ||
321 | case RC_HIGHER: | |
322 | higher: | |
323 | if (droppy == -1) { | |
324 | if (pp->f & F_VERBOSE) | |
325 | moan("probe returned: remote host is not a black hole"); | |
326 | droppy = 0; | |
327 | } | |
328 | if (mtu == hi) { | |
329 | if (pp->f & F_VERBOSE) moan("probe returned: found correct MTU"); | |
330 | goto done; | |
331 | } | |
88510d86 | 332 | lo = mtu; |
d245350a MW |
333 | |
334 | /* Now we must make a new guess, between lo and hi. We know that lo | |
335 | * is good; but we're not so sure about hi here. We know that hi > | |
336 | * lo, so this will find an approximate midpoint, greater than lo and | |
337 | * no more than hi. | |
338 | */ | |
339 | if (pp->f & F_VERBOSE) moan("probe returned: guessing higher"); | |
88510d86 MW |
340 | mtu += (hi - lo + 1)/2; |
341 | break; | |
342 | ||
343 | case RC_LOWER: | |
344 | lower: | |
d245350a MW |
345 | /* If this didn't work, and we're already at the bottom of our |
346 | * possible range, then something has gone horribly wrong. | |
347 | */ | |
348 | assert(lo < mtu); | |
349 | hi = mtu - 1; | |
350 | if (lo == hi) { | |
88510d86 | 351 | if (pp->f & F_VERBOSE) moan("error returned: found correct MTU"); |
d245350a | 352 | mtu = lo; |
88510d86 MW |
353 | goto done; |
354 | } | |
d245350a MW |
355 | |
356 | /* We must make a new guess, between lo and hi. We're probably | |
357 | * fairly sure that lo will succeed, since either it's the minimum | |
358 | * MTU or we've tested it already; but we're not quite sure about hi, | |
359 | * so we want to aim high. | |
360 | */ | |
88510d86 | 361 | if (pp->f & F_VERBOSE) moan("error returned: guessing lower"); |
88510d86 MW |
362 | mtu -= (hi - lo + 1)/2; |
363 | break; | |
364 | ||
365 | default: | |
366 | if (pp->f & F_VERBOSE) moan("error returned with new MTU estimate"); | |
367 | mtu = hi = rc; | |
368 | break; | |
369 | } | |
c64d8cd5 | 370 | } |
88510d86 MW |
371 | |
372 | done: | |
373 | /* Clean up and return our result. */ | |
374 | pp->pops->finish(st); | |
375 | xfree(st); | |
c64d8cd5 MW |
376 | close(sk); |
377 | return (mtu); | |
378 | ||
88510d86 MW |
379 | fail_3: |
380 | pp->pops->finish(st); | |
381 | fail_2: | |
382 | xfree(st); | |
c64d8cd5 MW |
383 | fail_1: |
384 | close(sk); | |
385 | fail_0: | |
386 | return (-1); | |
387 | } | |
388 | ||
88510d86 MW |
389 | /*----- Doing it the hard way ---------------------------------------------*/ |
390 | ||
85ccca5f MW |
391 | #ifdef HAVE_GETIFADDRS |
392 | ||
88510d86 | 393 | #if defined(linux) || defined(__OpenBSD__) |
4fcb3e51 | 394 | # define IPHDR_SANE |
88510d86 MW |
395 | #endif |
396 | ||
397 | #ifdef IPHDR_SANE | |
398 | # define sane_htons htons | |
399 | # define sane_htonl htonl | |
c64d8cd5 | 400 | #else |
88510d86 MW |
401 | # define sane_htons |
402 | # define sane_htonl | |
403 | #endif | |
404 | ||
405 | static int rawicmp = -1, rawudp = -1, rawerr = 0; | |
102fa2f0 | 406 | static int rawicmp6 = -1, rawudp6 = -1, rawerr6 = 0; |
88510d86 MW |
407 | |
408 | #define IPCK_INIT 0xffff | |
409 | ||
f03efaf5 MW |
410 | /* Compare two addresses. Maybe compare the port numbers too. */ |
411 | #define AEF_PORT 1u | |
412 | static int addreq(const union addr *a, const union addr *b, unsigned f) | |
413 | { | |
414 | switch (a->sa.sa_family) { | |
415 | case AF_INET: | |
416 | return (a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr && | |
417 | (!(f&AEF_PORT) || a->sin.sin_port == b->sin.sin_port)); | |
418 | case AF_INET6: | |
419 | return (!memcmp(a->sin6.sin6_addr.s6_addr, | |
420 | b->sin6.sin6_addr.s6_addr, 16) && | |
421 | (!(f&AEF_PORT) || a->sin6.sin6_port == b->sin6.sin6_port)); | |
422 | default: | |
423 | abort(); | |
424 | } | |
425 | } | |
426 | ||
88510d86 MW |
427 | /* Compute an IP checksum over some data. This is a restartable interface: |
428 | * initialize A to `IPCK_INIT' for the first call. | |
429 | */ | |
430 | static unsigned ipcksum(const void *buf, size_t n, unsigned a) | |
431 | { | |
432 | unsigned long aa = a ^ 0xffff; | |
433 | const unsigned char *p = buf, *l = p + n; | |
434 | ||
435 | while (p < l - 1) { aa += LOAD16_B(p); p += 2; } | |
436 | if (p < l) { aa += (unsigned)(*p) << 8; } | |
437 | do aa = (aa & 0xffff) + (aa >> 16); while (aa >= 0x10000); | |
438 | return (aa == 0xffff ? aa : aa ^ 0xffff); | |
439 | } | |
440 | ||
441 | /* TCP/UDP pseudoheader structure. */ | |
442 | struct phdr { | |
443 | struct in_addr ph_src, ph_dst; | |
1d25a3ed MW |
444 | uint8_t ph_z, ph_p; |
445 | uint16_t ph_len; | |
88510d86 | 446 | }; |
102fa2f0 MW |
447 | struct phdr6 { |
448 | struct in6_addr ph6_src, ph6_dst; | |
449 | uint32_t ph6_len; | |
450 | uint8_t ph6_z0, ph6_z1, ph6_z2, ph6_nxt; | |
451 | }; | |
88510d86 MW |
452 | |
453 | struct raw_state { | |
454f5a1a | 454 | union addr me, a; |
88510d86 | 455 | int sk, rawicmp, rawudp; |
5854b1cc | 456 | uint16_t srcport, dstport; |
88510d86 MW |
457 | unsigned q; |
458 | }; | |
459 | ||
460 | static int raw_setup(void *stv, int sk, const struct param *pp) | |
461 | { | |
462 | struct raw_state *st = stv; | |
cb160b86 | 463 | socklen_t sz; |
88510d86 MW |
464 | int i, mtu = -1; |
465 | struct ifaddrs *ifa, *ifaa, *ifap; | |
466 | struct ifreq ifr; | |
102fa2f0 | 467 | struct icmp6_filter f6; |
88510d86 | 468 | |
454f5a1a MW |
469 | /* Check that the address is OK, and that we have the necessary raw |
470 | * sockets. | |
102fa2f0 MW |
471 | * |
472 | * For IPv6, also set the filter so we don't get too many useless wakeups. | |
454f5a1a MW |
473 | */ |
474 | switch (pp->a.sa.sa_family) { | |
475 | case AF_INET: | |
476 | if (rawerr) { errno = rawerr; goto fail_0; } | |
477 | st->rawicmp = rawicmp; st->rawudp = rawudp; st->sk = sk; | |
102fa2f0 MW |
478 | /* IPv4 filtering is available on Linux but isn't portable. */ |
479 | break; | |
480 | case AF_INET6: | |
481 | if (rawerr6) { errno = rawerr6; goto fail_0; } | |
482 | st->rawicmp = rawicmp6; st->rawudp = rawudp6; st->sk = sk; | |
483 | ICMP6_FILTER_SETBLOCKALL(&f6); | |
484 | ICMP6_FILTER_SETPASS(ICMP6_PACKET_TOO_BIG, &f6); | |
485 | ICMP6_FILTER_SETPASS(ICMP6_DST_UNREACH, &f6); | |
486 | if (setsockopt(st->rawicmp, IPPROTO_ICMPV6, ICMP6_FILTER, | |
487 | &f6, sizeof(f6))) { | |
488 | die(EXIT_FAILURE, "failed to set icmpv6 filter: %s", | |
489 | strerror(errno)); | |
490 | } | |
454f5a1a MW |
491 | break; |
492 | default: | |
493 | errno = EPFNOSUPPORT; goto fail_0; | |
494 | } | |
88510d86 MW |
495 | |
496 | /* Initialize the sequence number. */ | |
497 | st->q = rand() & 0xffff; | |
498 | ||
499 | /* Snaffle the local and remote address and port number. */ | |
454f5a1a | 500 | st->a = pp->a; |
88510d86 | 501 | sz = sizeof(st->me); |
454f5a1a | 502 | if (getsockname(sk, &st->me.sa, &sz)) |
88510d86 MW |
503 | goto fail_0; |
504 | ||
102fa2f0 MW |
505 | /* Only now do some fiddling because Linux doesn't like port numbers in |
506 | * IPv6 raw destination addresses... | |
507 | */ | |
b9e97e20 MW |
508 | switch (pp->a.sa.sa_family) { |
509 | case AF_INET: | |
510 | st->srcport = st->me.sin.sin_port; st->me.sin.sin_port = 0; | |
511 | st->dstport = st->a.sin.sin_port; st->a.sin.sin_port = 0; | |
512 | break; | |
102fa2f0 MW |
513 | case AF_INET6: |
514 | st->srcport = st->me.sin6.sin6_port; st->me.sin6.sin6_port = 0; | |
515 | st->dstport = st->a.sin6.sin6_port; st->a.sin6.sin6_port = 0; | |
516 | break; | |
b9e97e20 MW |
517 | default: |
518 | abort(); | |
519 | } | |
5854b1cc | 520 | |
88510d86 MW |
521 | /* There isn't a portable way to force the DF flag onto a packet through |
522 | * UDP, or even through raw IP, unless we write the entire IP header | |
523 | * ourselves. This is somewhat annoying, especially since we have an | |
524 | * uphill struggle keeping track of which systems randomly expect which | |
525 | * header fields to be presented in host byte order. Oh, well. | |
526 | */ | |
527 | i = 1; | |
528 | if (setsockopt(rawudp, IPPROTO_IP, IP_HDRINCL, &i, sizeof(i))) goto fail_0; | |
529 | ||
530 | /* Find an upper bound on the MTU. Do two passes over the interface | |
531 | * list. If we can find matches for our local address then use the | |
532 | * highest one of those; otherwise do a second pass and simply take the | |
533 | * highest MTU of any network interface. | |
534 | */ | |
535 | if (getifaddrs(&ifaa)) goto fail_0; | |
536 | for (i = 0; i < 2; i++) { | |
537 | for (ifap = 0, ifa = ifaa; ifa; ifa = ifa->ifa_next) { | |
538 | if (!(ifa->ifa_flags & IFF_UP) || !ifa->ifa_addr || | |
454f5a1a | 539 | ifa->ifa_addr->sa_family != st->me.sa.sa_family || |
88510d86 | 540 | (i == 0 && |
454f5a1a | 541 | !addreq((union addr *)ifa->ifa_addr, &st->me, 0)) || |
88510d86 MW |
542 | (i == 1 && ifap && strcmp(ifap->ifa_name, ifa->ifa_name) == 0) || |
543 | strlen(ifa->ifa_name) >= sizeof(ifr.ifr_name)) | |
544 | continue; | |
545 | ifap = ifa; | |
546 | strcpy(ifr.ifr_name, ifa->ifa_name); | |
547 | if (ioctl(sk, SIOCGIFMTU, &ifr)) goto fail_1; | |
548 | if (mtu < ifr.ifr_mtu) mtu = ifr.ifr_mtu; | |
549 | } | |
550 | if (mtu > 0) break; | |
551 | } | |
552 | if (mtu < 0) { errno = ENOTCONN; goto fail_1; } | |
553 | freeifaddrs(ifaa); | |
554 | ||
555 | /* Done. */ | |
556 | return (mtu); | |
557 | ||
558 | fail_1: | |
559 | freeifaddrs(ifaa); | |
560 | fail_0: | |
561 | return (-1); | |
562 | } | |
563 | ||
564 | static void raw_finish(void *stv) { ; } | |
565 | ||
566 | static void raw_selprep(void *stv, int *maxfd, fd_set *fd_in) | |
567 | { struct raw_state *st = stv; ADDFD(st->sk); ADDFD(st->rawicmp); } | |
568 | ||
569 | static int raw_xmit(void *stv, int mtu) | |
570 | { | |
571 | struct raw_state *st = stv; | |
572 | unsigned char b[65536], *p; | |
573 | struct ip *ip; | |
102fa2f0 | 574 | struct ip6_hdr *ip6; |
88510d86 MW |
575 | struct udphdr *udp; |
576 | struct phdr ph; | |
102fa2f0 | 577 | struct phdr6 ph6; |
88510d86 MW |
578 | unsigned ck; |
579 | ||
b9e97e20 MW |
580 | switch (st->a.sa.sa_family) { |
581 | ||
582 | case AF_INET: | |
583 | ||
584 | /* Build the IP header. */ | |
585 | ip = (struct ip *)b; | |
586 | ip->ip_v = 4; | |
587 | ip->ip_hl = sizeof(*ip)/4; | |
588 | ip->ip_tos = IPTOS_RELIABILITY; | |
589 | ip->ip_len = sane_htons(mtu); | |
590 | STEP(st->q); ip->ip_id = htons(st->q); | |
591 | ip->ip_off = sane_htons(0 | IP_DF); | |
592 | ip->ip_ttl = 64; | |
593 | ip->ip_p = IPPROTO_UDP; | |
594 | ip->ip_sum = 0; | |
595 | ip->ip_src = st->me.sin.sin_addr; | |
596 | ip->ip_dst = st->a.sin.sin_addr; | |
597 | ||
598 | /* Build a UDP packet in the output buffer. */ | |
599 | udp = (struct udphdr *)(ip + 1); | |
600 | udp->uh_sport = st->srcport; | |
601 | udp->uh_dport = st->dstport; | |
602 | udp->uh_ulen = htons(mtu - sizeof(*ip)); | |
603 | udp->uh_sum = 0; | |
604 | ||
605 | /* Copy the payload. */ | |
606 | p = (unsigned char *)(udp + 1); | |
607 | memcpy(p, buf, mtu - (p - b)); | |
608 | ||
609 | /* Calculate the UDP checksum. */ | |
610 | ph.ph_src = ip->ip_src; | |
611 | ph.ph_dst = ip->ip_dst; | |
612 | ph.ph_z = 0; | |
613 | ph.ph_p = IPPROTO_UDP; | |
614 | ph.ph_len = udp->uh_ulen; | |
615 | ck = IPCK_INIT; | |
616 | ck = ipcksum(&ph, sizeof(ph), ck); | |
617 | ck = ipcksum(udp, mtu - sizeof(*ip), ck); | |
618 | udp->uh_sum = htons(ck); | |
619 | ||
620 | break; | |
621 | ||
102fa2f0 MW |
622 | case AF_INET6: |
623 | ||
624 | /* Build the IP header. */ | |
625 | ip6 = (struct ip6_hdr *)b; | |
626 | STEP(st->q); ip6->ip6_flow = htonl(0x60000000 | st->q); | |
627 | ip6->ip6_plen = htons(mtu - sizeof(*ip6)); | |
628 | ip6->ip6_nxt = IPPROTO_UDP; | |
629 | ip6->ip6_hlim = 64; | |
630 | ip6->ip6_src = st->me.sin6.sin6_addr; | |
631 | ip6->ip6_dst = st->a.sin6.sin6_addr; | |
632 | ||
633 | /* Build a UDP packet in the output buffer. */ | |
634 | udp = (struct udphdr *)(ip6 + 1); | |
635 | udp->uh_sport = st->srcport; | |
636 | udp->uh_dport = st->dstport; | |
637 | udp->uh_ulen = htons(mtu - sizeof(*ip6)); | |
638 | udp->uh_sum = 0; | |
639 | ||
640 | /* Copy the payload. */ | |
641 | p = (unsigned char *)(udp + 1); | |
642 | memcpy(p, buf, mtu - (p - b)); | |
643 | ||
644 | /* Calculate the UDP checksum. */ | |
645 | ph6.ph6_src = ip6->ip6_src; | |
646 | ph6.ph6_dst = ip6->ip6_dst; | |
647 | ph6.ph6_len = udp->uh_ulen; | |
648 | ph6.ph6_z0 = ph6.ph6_z1 = ph6.ph6_z2 = 0; | |
649 | ph6.ph6_nxt = IPPROTO_UDP; | |
650 | ck = IPCK_INIT; | |
651 | ck = ipcksum(&ph6, sizeof(ph6), ck); | |
652 | ck = ipcksum(udp, mtu - sizeof(*ip6), ck); | |
653 | udp->uh_sum = htons(ck); | |
654 | ||
655 | break; | |
656 | ||
b9e97e20 MW |
657 | default: |
658 | abort(); | |
659 | } | |
88510d86 MW |
660 | |
661 | /* Send the whole thing off. If we're too big for the interface then we | |
662 | * might need to trim immediately. | |
663 | */ | |
454f5a1a | 664 | if (sendto(st->rawudp, b, mtu, 0, &st->a.sa, addrsz(&st->a)) < 0) { |
88510d86 MW |
665 | if (errno == EMSGSIZE) return (RC_LOWER); |
666 | else goto fail_0; | |
667 | } | |
668 | ||
669 | /* Done. */ | |
670 | return (RC_OK); | |
671 | ||
672 | fail_0: | |
673 | return (RC_FAIL); | |
674 | } | |
675 | ||
676 | static int raw_selproc(void *stv, fd_set *fd_in, struct probestate *ps) | |
677 | { | |
678 | struct raw_state *st = stv; | |
679 | unsigned char b[65536]; | |
680 | struct ip *ip; | |
102fa2f0 | 681 | struct ip6_hdr *ip6; |
88510d86 | 682 | struct icmp *icmp; |
102fa2f0 | 683 | struct icmp6_hdr *icmp6; |
88510d86 | 684 | struct udphdr *udp; |
9ad20ce0 | 685 | const unsigned char *payload; |
88510d86 MW |
686 | ssize_t n; |
687 | ||
688 | /* An ICMP packet: see what's inside. */ | |
689 | if (FD_ISSET(st->rawicmp, fd_in)) { | |
690 | if ((n = read(st->rawicmp, b, sizeof(b))) < 0) goto fail_0; | |
691 | ||
b9e97e20 MW |
692 | switch (st->me.sa.sa_family) { |
693 | ||
694 | case AF_INET: | |
695 | ||
696 | ip = (struct ip *)b; | |
697 | if (n < sizeof(*ip) || n < sizeof(4*ip->ip_hl) || | |
698 | ip->ip_v != 4 || ip->ip_p != IPPROTO_ICMP) | |
699 | goto skip_icmp; | |
700 | n -= sizeof(4*ip->ip_hl); | |
701 | ||
702 | icmp = (struct icmp *)(b + 4*ip->ip_hl); | |
703 | if (n < sizeof(*icmp) || icmp->icmp_type != ICMP_UNREACH) | |
704 | goto skip_icmp; | |
705 | n -= offsetof(struct icmp, icmp_ip); | |
706 | ||
707 | ip = &icmp->icmp_ip; | |
708 | if (n < sizeof(*ip) || | |
709 | ip->ip_p != IPPROTO_UDP || ip->ip_hl != sizeof(*ip)/4 || | |
710 | ip->ip_id != htons(st->q) || | |
711 | ip->ip_src.s_addr != st->me.sin.sin_addr.s_addr || | |
712 | ip->ip_dst.s_addr != st->a.sin.sin_addr.s_addr) | |
713 | goto skip_icmp; | |
714 | n -= sizeof(*ip); | |
715 | ||
716 | udp = (struct udphdr *)(ip + 1); | |
717 | if (n < sizeof(*udp) || udp->uh_sport != st->srcport || | |
718 | udp->uh_dport != st->dstport) | |
719 | goto skip_icmp; | |
720 | n -= sizeof(*udp); | |
721 | ||
722 | payload = (const unsigned char *)(udp + 1); | |
723 | if (!mypacketp(ps, payload, n)) goto skip_icmp; | |
724 | ||
725 | if (icmp->icmp_code == ICMP_UNREACH_PORT) return (RC_HIGHER); | |
726 | else if (icmp->icmp_code != ICMP_UNREACH_NEEDFRAG) goto skip_icmp; | |
727 | else if (icmp->icmp_nextmtu) return (htons(icmp->icmp_nextmtu)); | |
728 | else return (RC_LOWER); | |
729 | ||
730 | break; | |
731 | ||
102fa2f0 MW |
732 | case AF_INET6: |
733 | icmp6 = (struct icmp6_hdr *)b; | |
734 | if (n < sizeof(*icmp6) || | |
735 | (icmp6->icmp6_type != ICMP6_PACKET_TOO_BIG && | |
736 | icmp6->icmp6_type != ICMP6_DST_UNREACH)) | |
737 | goto skip_icmp; | |
738 | n -= sizeof(*icmp6); | |
739 | ||
740 | ip6 = (struct ip6_hdr *)(icmp6 + 1); | |
741 | if (n < sizeof(*ip6) || ip6->ip6_nxt != IPPROTO_UDP || | |
742 | memcmp(ip6->ip6_src.s6_addr, | |
743 | st->me.sin6.sin6_addr.s6_addr, 16) || | |
744 | memcmp(ip6->ip6_dst.s6_addr, | |
745 | st->a.sin6.sin6_addr.s6_addr, 16) || | |
746 | (ntohl(ip6->ip6_flow)&0xffff) != st->q) | |
747 | goto skip_icmp; | |
748 | n -= sizeof(*ip6); | |
749 | ||
750 | udp = (struct udphdr *)(ip6 + 1); | |
751 | if (n < sizeof(*udp) || udp->uh_sport != st->srcport || | |
752 | udp->uh_dport != st->dstport) | |
753 | goto skip_icmp; | |
754 | n -= sizeof(*udp); | |
755 | ||
756 | payload = (const unsigned char *)(udp + 1); | |
757 | if (!mypacketp(ps, payload, n)) goto skip_icmp; | |
758 | ||
759 | if (icmp6->icmp6_type == ICMP6_PACKET_TOO_BIG) | |
760 | return (ntohs(icmp6->icmp6_mtu)); | |
761 | else switch (icmp6->icmp6_code) { | |
762 | case ICMP6_DST_UNREACH_ADMIN: | |
763 | case ICMP6_DST_UNREACH_NOPORT: | |
764 | return (RC_HIGHER); | |
765 | default: | |
766 | goto skip_icmp; | |
767 | } | |
768 | break; | |
769 | ||
b9e97e20 MW |
770 | default: |
771 | abort(); | |
772 | } | |
88510d86 | 773 | } |
b9e97e20 | 774 | |
88510d86 MW |
775 | skip_icmp:; |
776 | ||
777 | /* If we got a reply to the current probe then we're good. If we got an | |
778 | * error, or the packet's sequence number is wrong, then ignore it. | |
779 | */ | |
780 | if (FD_ISSET(st->sk, fd_in)) { | |
781 | if ((n = read(st->sk, b, sizeof(b))) < 0) return (RC_OK); | |
782 | else if (mypacketp(ps, b, n)) return (RC_HIGHER); | |
783 | else return (RC_OK); | |
784 | } | |
785 | ||
786 | return (RC_OK); | |
787 | ||
788 | fail_0: | |
789 | return (RC_FAIL); | |
790 | } | |
791 | ||
792 | static const struct probe_ops raw_ops = { | |
793 | "raw", OPS_CHAIN, sizeof(struct raw_state), | |
794 | raw_setup, raw_finish, | |
795 | raw_selprep, raw_xmit, raw_selproc | |
796 | }; | |
797 | ||
798 | #undef OPS_CHAIN | |
799 | #define OPS_CHAIN &raw_ops | |
800 | ||
85ccca5f MW |
801 | #endif |
802 | ||
88510d86 MW |
803 | /*----- Doing the job on Linux --------------------------------------------*/ |
804 | ||
805 | #if defined(linux) | |
806 | ||
807 | #ifndef IP_MTU | |
808 | # define IP_MTU 14 /* Blech! */ | |
809 | #endif | |
810 | ||
811 | struct linux_state { | |
10583b59 | 812 | int sol, so_mtu_discover, so_mtu; |
88510d86 | 813 | int sk; |
10583b59 | 814 | size_t hdrlen; |
88510d86 MW |
815 | }; |
816 | ||
817 | static int linux_setup(void *stv, int sk, const struct param *pp) | |
818 | { | |
819 | struct linux_state *st = stv; | |
820 | int i, mtu; | |
cb160b86 | 821 | socklen_t sz; |
88510d86 | 822 | |
454f5a1a MW |
823 | /* Check that the address is OK. */ |
824 | switch (pp->a.sa.sa_family) { | |
10583b59 MW |
825 | case AF_INET: |
826 | st->sol = IPPROTO_IP; | |
827 | st->so_mtu_discover = IP_MTU_DISCOVER; | |
828 | st->so_mtu = IP_MTU; | |
829 | st->hdrlen = 28; | |
830 | break; | |
831 | case AF_INET6: | |
832 | st->sol = IPPROTO_IPV6; | |
833 | st->so_mtu_discover = IPV6_MTU_DISCOVER; | |
834 | st->so_mtu = IPV6_MTU; | |
835 | st->hdrlen = 48; | |
836 | break; | |
837 | default: | |
838 | errno = EPFNOSUPPORT; | |
839 | return (-1); | |
454f5a1a MW |
840 | } |
841 | ||
88510d86 MW |
842 | /* Snaffle the UDP socket. */ |
843 | st->sk = sk; | |
844 | ||
845 | /* Turn on kernel path-MTU discovery and force DF on. */ | |
18d5f6eb | 846 | i = IP_PMTUDISC_PROBE; |
10583b59 | 847 | if (setsockopt(st->sk, st->sol, st->so_mtu_discover, &i, sizeof(i))) |
88510d86 MW |
848 | return (-1); |
849 | ||
850 | /* Read the initial MTU guess back and report it. */ | |
851 | sz = sizeof(mtu); | |
10583b59 | 852 | if (getsockopt(st->sk, st->sol, st->so_mtu, &mtu, &sz)) |
88510d86 MW |
853 | return (-1); |
854 | ||
855 | /* Done. */ | |
856 | return (mtu); | |
857 | } | |
858 | ||
859 | static void linux_finish(void *stv) { ; } | |
860 | ||
861 | static void linux_selprep(void *stv, int *maxfd, fd_set *fd_in) | |
862 | { struct linux_state *st = stv; ADDFD(st->sk); } | |
863 | ||
864 | static int linux_xmit(void *stv, int mtu) | |
865 | { | |
866 | struct linux_state *st = stv; | |
867 | ||
868 | /* Write the packet. */ | |
10583b59 | 869 | if (write(st->sk, buf, mtu - st->hdrlen) >= 0) return (RC_OK); |
88510d86 MW |
870 | else if (errno == EMSGSIZE) return (RC_LOWER); |
871 | else return (RC_FAIL); | |
872 | } | |
873 | ||
874 | static int linux_selproc(void *stv, fd_set *fd_in, struct probestate *ps) | |
875 | { | |
876 | struct linux_state *st = stv; | |
877 | int mtu; | |
cb160b86 | 878 | socklen_t sz; |
88510d86 MW |
879 | ssize_t n; |
880 | unsigned char b[65536]; | |
881 | ||
882 | /* Read an answer. If it looks like the right kind of error then report a | |
883 | * success. This is potentially wrong, since we can't tell whether an | |
884 | * error was delayed from an earlier probe. However, we never return | |
885 | * RC_LOWER from this method, so the packet sizes ought to be monotonically | |
886 | * decreasing and this won't cause trouble. Otherwise update from the | |
887 | * kernel's idea of the right MTU. | |
888 | */ | |
889 | if (FD_ISSET(st->sk, fd_in)) { | |
890 | n = read(st->sk, &buf, sizeof(buf)); | |
891 | if (n >= 0 ? | |
892 | mypacketp(ps, b, n) : | |
893 | errno == ECONNREFUSED || errno == EHOSTUNREACH) | |
894 | return (RC_HIGHER); | |
895 | sz = sizeof(mtu); | |
10583b59 | 896 | if (getsockopt(st->sk, st->sol, st->so_mtu, &mtu, &sz)) |
88510d86 MW |
897 | return (RC_FAIL); |
898 | return (mtu); | |
899 | } | |
900 | return (RC_OK); | |
901 | } | |
902 | ||
903 | static const struct probe_ops linux_ops = { | |
904 | "linux", OPS_CHAIN, sizeof(struct linux_state), | |
905 | linux_setup, linux_finish, | |
906 | linux_selprep, linux_xmit, linux_selproc | |
907 | }; | |
c64d8cd5 | 908 | |
88510d86 MW |
909 | #undef OPS_CHAIN |
910 | #define OPS_CHAIN &linux_ops | |
c64d8cd5 MW |
911 | |
912 | #endif | |
913 | ||
914 | /*----- Help options ------------------------------------------------------*/ | |
915 | ||
88510d86 MW |
916 | static const struct probe_ops *probe_ops = OPS_CHAIN; |
917 | ||
c64d8cd5 MW |
918 | static void version(FILE *fp) |
919 | { pquis(fp, "$, TrIPE version " VERSION "\n"); } | |
920 | ||
921 | static void usage(FILE *fp) | |
88510d86 | 922 | { |
22062fb6 | 923 | pquis(fp, "Usage: $ [-46v] [-H HEADER] [-m METHOD]\n\ |
88510d86 MW |
924 | [-r SECS] [-g FACTOR] [-t SECS] HOST [PORT]\n"); |
925 | } | |
c64d8cd5 MW |
926 | |
927 | static void help(FILE *fp) | |
928 | { | |
88510d86 MW |
929 | const struct probe_ops *ops; |
930 | ||
c64d8cd5 MW |
931 | version(fp); |
932 | fputc('\n', fp); | |
933 | usage(fp); | |
934 | fputs("\ | |
935 | \n\ | |
936 | Options in full:\n\ | |
937 | \n\ | |
938 | -h, --help Show this help text.\n\ | |
b13c3272 | 939 | -V, --version Show version number.\n\ |
c64d8cd5 MW |
940 | -u, --usage Show brief usage message.\n\ |
941 | \n\ | |
22062fb6 MW |
942 | -4, --ipv4 Restrict to IPv4 only.\n\ |
943 | -6, --ipv6 Restrict to IPv6 only.\n\ | |
88510d86 MW |
944 | -g, --growth=FACTOR Growth factor for retransmit interval.\n\ |
945 | -m, --method=METHOD Use METHOD to probe for MTU.\n\ | |
946 | -r, --retransmit=SECS Retransmit if no reply after SEC.\n\ | |
947 | -t, --timeout=SECS Give up expecting a reply after SECS.\n\ | |
a8f70fe1 | 948 | -v, --verbose Write a running commentary to stderr.\n\ |
c64d8cd5 | 949 | -H, --header=HEX Packet header, in hexadecimal.\n\ |
88510d86 MW |
950 | \n\ |
951 | Probe methods:\n\ | |
c64d8cd5 | 952 | ", fp); |
88510d86 MW |
953 | for (ops = probe_ops; ops; ops = ops->next) |
954 | printf("\t%s\n", ops->name); | |
c64d8cd5 MW |
955 | } |
956 | ||
957 | /*----- Main code ---------------------------------------------------------*/ | |
958 | ||
959 | int main(int argc, char *argv[]) | |
960 | { | |
88510d86 | 961 | struct param pp = { 0, 0.333, 3.0, 8.0, 0, OPS_CHAIN }; |
c64d8cd5 MW |
962 | hex_ctx hc; |
963 | dstr d = DSTR_INIT; | |
964 | size_t sz; | |
22062fb6 MW |
965 | int i, err; |
966 | struct addrinfo aihint = { 0 }, *ailist, *ai; | |
967 | const char *host, *svc = "7"; | |
c64d8cd5 MW |
968 | unsigned f = 0; |
969 | ||
970 | #define f_bogus 1u | |
971 | ||
85ccca5f | 972 | #ifdef HAVE_GETIFADDRS |
88510d86 MW |
973 | if ((rawicmp = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0 || |
974 | (rawudp = socket(PF_INET, SOCK_RAW, IPPROTO_UDP)) < 0) | |
975 | rawerr = errno; | |
102fa2f0 MW |
976 | if ((rawicmp6 = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0 || |
977 | (rawudp6 = socket(PF_INET6, SOCK_RAW, IPPROTO_RAW)) < 0) | |
978 | rawerr6 = errno; | |
85ccca5f | 979 | #endif |
88510d86 MW |
980 | if (setuid(getuid())) |
981 | abort(); | |
982 | ||
c64d8cd5 MW |
983 | ego(argv[0]); |
984 | fillbuffer(buf, sizeof(buf)); | |
22062fb6 MW |
985 | |
986 | aihint.ai_family = AF_UNSPEC; | |
987 | aihint.ai_protocol = IPPROTO_UDP; | |
988 | aihint.ai_socktype = SOCK_DGRAM; | |
989 | aihint.ai_flags = AI_ADDRCONFIG; | |
c64d8cd5 MW |
990 | |
991 | for (;;) { | |
992 | static const struct option opts[] = { | |
993 | { "help", 0, 0, 'h' }, | |
88510d86 | 994 | { "version", 0, 0, 'V' }, |
c64d8cd5 | 995 | { "usage", 0, 0, 'u' }, |
22062fb6 MW |
996 | { "ipv4", 0, 0, '4' }, |
997 | { "ipv6", 0, 0, '6' }, | |
c64d8cd5 | 998 | { "header", OPTF_ARGREQ, 0, 'H' }, |
88510d86 MW |
999 | { "growth", OPTF_ARGREQ, 0, 'g' }, |
1000 | { "method", OPTF_ARGREQ, 0, 'm' }, | |
1001 | { "retransmit", OPTF_ARGREQ, 0, 'r' }, | |
c64d8cd5 | 1002 | { "timeout", OPTF_ARGREQ, 0, 't' }, |
88510d86 | 1003 | { "verbose", 0, 0, 'v' }, |
c64d8cd5 MW |
1004 | { 0, 0, 0, 0 } |
1005 | }; | |
1006 | ||
22062fb6 | 1007 | i = mdwopt(argc, argv, "hVu" "46H:g:m:r:t:v", opts, 0, 0, 0); |
c64d8cd5 MW |
1008 | if (i < 0) break; |
1009 | switch (i) { | |
1010 | case 'h': help(stdout); exit(0); | |
88510d86 | 1011 | case 'V': version(stdout); exit(0); |
c64d8cd5 MW |
1012 | case 'u': usage(stdout); exit(0); |
1013 | ||
1014 | case 'H': | |
1015 | DRESET(&d); | |
1016 | hex_init(&hc); | |
1017 | hex_decode(&hc, optarg, strlen(optarg), &d); | |
1018 | hex_decode(&hc, 0, 0, &d); | |
88510d86 | 1019 | sz = d.len < 532 ? d.len : 532; |
c64d8cd5 | 1020 | memcpy(buf, d.buf, sz); |
88510d86 | 1021 | pp.seqoff = sz; |
c64d8cd5 MW |
1022 | break; |
1023 | ||
22062fb6 MW |
1024 | case '4': aihint.ai_family = AF_INET; break; |
1025 | case '6': aihint.ai_family = AF_INET6; break; | |
88510d86 MW |
1026 | case 'g': pp.regr = s2f(optarg, "retransmit growth factor"); break; |
1027 | case 'r': pp.retx = s2f(optarg, "retransmit interval"); break; | |
1028 | case 't': pp.timeout = s2f(optarg, "timeout"); break; | |
1029 | ||
1030 | case 'm': | |
1031 | for (pp.pops = OPS_CHAIN; pp.pops; pp.pops = pp.pops->next) | |
1032 | if (strcmp(pp.pops->name, optarg) == 0) goto found_alg; | |
1033 | die(EXIT_FAILURE, "unknown probe algorithm `%s'", optarg); | |
1034 | found_alg: | |
c64d8cd5 MW |
1035 | break; |
1036 | ||
88510d86 MW |
1037 | case 'v': pp.f |= F_VERBOSE; break; |
1038 | ||
c64d8cd5 MW |
1039 | default: |
1040 | f |= f_bogus; | |
1041 | break; | |
1042 | } | |
1043 | } | |
1044 | argv += optind; argc -= optind; | |
1045 | if ((f & f_bogus) || 1 > argc || argc > 2) { | |
1046 | usage(stderr); | |
1047 | exit(EXIT_FAILURE); | |
1048 | } | |
1049 | ||
22062fb6 MW |
1050 | host = argv[0]; |
1051 | if (argv[1]) svc = argv[1]; | |
1052 | if ((err = getaddrinfo(host, svc, &aihint, &ailist)) != 0) { | |
1053 | die(EXIT_FAILURE, "unknown host `%s' or service `%s': %s", | |
1054 | host, svc, gai_strerror(err)); | |
c64d8cd5 | 1055 | } |
22062fb6 MW |
1056 | for (ai = ailist; ai && !addrfamok(ai->ai_family); ai = ai->ai_next); |
1057 | if (!ai) die(EXIT_FAILURE, "no supported address families for `%s'", host); | |
1058 | assert(ai->ai_addrlen <= sizeof(pp.a)); | |
1059 | memcpy(&pp.a, ai->ai_addr, ai->ai_addrlen); | |
c64d8cd5 | 1060 | |
88510d86 | 1061 | i = pathmtu(&pp); |
c64d8cd5 MW |
1062 | if (i < 0) |
1063 | die(EXIT_FAILURE, "failed to discover MTU: %s", strerror(errno)); | |
1064 | printf("%d\n", i); | |
1065 | if (ferror(stdout) || fflush(stdout) || fclose(stdout)) | |
1066 | die(EXIT_FAILURE, "failed to write result: %s", strerror(errno)); | |
1067 | return (0); | |
1068 | } | |
1069 | ||
1070 | /*----- That's all, folks -------------------------------------------------*/ |