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