Lorenzo Colitti | 313379e | 2013-07-11 01:07:11 +0900 | [diff] [blame] | 1 | /* |
| 2 | * tracepath.c |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License |
| 6 | * as published by the Free Software Foundation; either version |
| 7 | * 2 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> |
| 10 | */ |
| 11 | |
| 12 | #include <stdio.h> |
| 13 | #include <stdlib.h> |
| 14 | #include <unistd.h> |
| 15 | #include <sys/socket.h> |
| 16 | #include <linux/types.h> |
| 17 | #include <linux/errqueue.h> |
| 18 | #include <errno.h> |
| 19 | #include <string.h> |
| 20 | #include <netdb.h> |
| 21 | #include <netinet/in.h> |
| 22 | #include <resolv.h> |
| 23 | #include <sys/time.h> |
| 24 | #include <sys/uio.h> |
| 25 | #include <arpa/inet.h> |
| 26 | #ifdef USE_IDN |
| 27 | #include <idna.h> |
| 28 | #include <locale.h> |
| 29 | #endif |
| 30 | |
| 31 | #ifndef IP_PMTUDISC_PROBE |
| 32 | #define IP_PMTUDISC_PROBE 3 |
| 33 | #endif |
| 34 | |
| 35 | #define MAX_HOPS_LIMIT 255 |
| 36 | #define MAX_HOPS_DEFAULT 30 |
| 37 | |
| 38 | struct hhistory |
| 39 | { |
| 40 | int hops; |
| 41 | struct timeval sendtime; |
| 42 | }; |
| 43 | |
| 44 | struct hhistory his[64]; |
| 45 | int hisptr; |
| 46 | |
| 47 | struct sockaddr_in target; |
| 48 | __u16 base_port; |
| 49 | int max_hops = MAX_HOPS_DEFAULT; |
| 50 | |
| 51 | const int overhead = 28; |
| 52 | int mtu = 65535; |
| 53 | void *pktbuf; |
| 54 | int hops_to = -1; |
| 55 | int hops_from = -1; |
| 56 | int no_resolve = 0; |
| 57 | int show_both = 0; |
| 58 | |
| 59 | #define HOST_COLUMN_SIZE 52 |
| 60 | |
| 61 | struct probehdr |
| 62 | { |
| 63 | __u32 ttl; |
| 64 | struct timeval tv; |
| 65 | }; |
| 66 | |
| 67 | void data_wait(int fd) |
| 68 | { |
| 69 | fd_set fds; |
| 70 | struct timeval tv; |
| 71 | FD_ZERO(&fds); |
| 72 | FD_SET(fd, &fds); |
| 73 | tv.tv_sec = 1; |
| 74 | tv.tv_usec = 0; |
| 75 | select(fd+1, &fds, NULL, NULL, &tv); |
| 76 | } |
| 77 | |
| 78 | void print_host(const char *a, const char *b, int both) |
| 79 | { |
| 80 | int plen; |
| 81 | plen = printf("%s", a); |
| 82 | if (both) |
| 83 | plen += printf(" (%s)", b); |
| 84 | if (plen >= HOST_COLUMN_SIZE) |
| 85 | plen = HOST_COLUMN_SIZE - 1; |
| 86 | printf("%*s", HOST_COLUMN_SIZE - plen, ""); |
| 87 | } |
| 88 | |
| 89 | int recverr(int fd, int ttl) |
| 90 | { |
| 91 | int res; |
| 92 | struct probehdr rcvbuf; |
| 93 | char cbuf[512]; |
| 94 | struct iovec iov; |
| 95 | struct msghdr msg; |
| 96 | struct cmsghdr *cmsg; |
| 97 | struct sock_extended_err *e; |
| 98 | struct sockaddr_in addr; |
| 99 | struct timeval tv; |
| 100 | struct timeval *rettv; |
| 101 | int slot; |
| 102 | int rethops; |
| 103 | int sndhops; |
| 104 | int progress = -1; |
| 105 | int broken_router; |
| 106 | |
| 107 | restart: |
| 108 | memset(&rcvbuf, -1, sizeof(rcvbuf)); |
| 109 | iov.iov_base = &rcvbuf; |
| 110 | iov.iov_len = sizeof(rcvbuf); |
| 111 | msg.msg_name = (__u8*)&addr; |
| 112 | msg.msg_namelen = sizeof(addr); |
| 113 | msg.msg_iov = &iov; |
| 114 | msg.msg_iovlen = 1; |
| 115 | msg.msg_flags = 0; |
| 116 | msg.msg_control = cbuf; |
| 117 | msg.msg_controllen = sizeof(cbuf); |
| 118 | |
| 119 | gettimeofday(&tv, NULL); |
| 120 | res = recvmsg(fd, &msg, MSG_ERRQUEUE); |
| 121 | if (res < 0) { |
| 122 | if (errno == EAGAIN) |
| 123 | return progress; |
| 124 | goto restart; |
| 125 | } |
| 126 | |
| 127 | progress = mtu; |
| 128 | |
| 129 | rethops = -1; |
| 130 | sndhops = -1; |
| 131 | e = NULL; |
| 132 | rettv = NULL; |
| 133 | slot = ntohs(addr.sin_port) - base_port; |
| 134 | if (slot>=0 && slot < 63 && his[slot].hops) { |
| 135 | sndhops = his[slot].hops; |
| 136 | rettv = &his[slot].sendtime; |
| 137 | his[slot].hops = 0; |
| 138 | } |
| 139 | broken_router = 0; |
| 140 | if (res == sizeof(rcvbuf)) { |
| 141 | if (rcvbuf.ttl == 0 || rcvbuf.tv.tv_sec == 0) { |
| 142 | broken_router = 1; |
| 143 | } else { |
| 144 | sndhops = rcvbuf.ttl; |
| 145 | rettv = &rcvbuf.tv; |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
| 150 | if (cmsg->cmsg_level == SOL_IP) { |
| 151 | if (cmsg->cmsg_type == IP_RECVERR) { |
| 152 | e = (struct sock_extended_err *) CMSG_DATA(cmsg); |
| 153 | } else if (cmsg->cmsg_type == IP_TTL) { |
| 154 | memcpy(&rethops, CMSG_DATA(cmsg), sizeof(rethops)); |
| 155 | } else { |
| 156 | printf("cmsg:%d\n ", cmsg->cmsg_type); |
| 157 | } |
| 158 | } |
| 159 | } |
| 160 | if (e == NULL) { |
| 161 | printf("no info\n"); |
| 162 | return 0; |
| 163 | } |
| 164 | if (e->ee_origin == SO_EE_ORIGIN_LOCAL) { |
| 165 | printf("%2d?: %*s ", ttl, -(HOST_COLUMN_SIZE - 1), "[LOCALHOST]"); |
| 166 | } else if (e->ee_origin == SO_EE_ORIGIN_ICMP) { |
| 167 | char abuf[128]; |
| 168 | struct sockaddr_in *sin = (struct sockaddr_in*)(e+1); |
| 169 | struct hostent *h = NULL; |
| 170 | char *idn = NULL; |
| 171 | |
| 172 | inet_ntop(AF_INET, &sin->sin_addr, abuf, sizeof(abuf)); |
| 173 | |
| 174 | if (sndhops>0) |
| 175 | printf("%2d: ", sndhops); |
| 176 | else |
| 177 | printf("%2d?: ", ttl); |
| 178 | |
| 179 | if (!no_resolve || show_both) { |
| 180 | fflush(stdout); |
| 181 | h = gethostbyaddr((char *) &sin->sin_addr, sizeof(sin->sin_addr), AF_INET); |
| 182 | } |
| 183 | |
| 184 | #ifdef USE_IDN |
| 185 | if (h && idna_to_unicode_lzlz(h->h_name, &idn, 0) != IDNA_SUCCESS) |
| 186 | idn = NULL; |
| 187 | #endif |
| 188 | if (no_resolve) |
| 189 | print_host(abuf, h ? (idn ? idn : h->h_name) : abuf, show_both); |
| 190 | else |
| 191 | print_host(h ? (idn ? idn : h->h_name) : abuf, abuf, show_both); |
| 192 | |
| 193 | #ifdef USE_IDN |
| 194 | free(idn); |
| 195 | #endif |
| 196 | } |
| 197 | |
| 198 | if (rettv) { |
| 199 | int diff = (tv.tv_sec-rettv->tv_sec)*1000000+(tv.tv_usec-rettv->tv_usec); |
| 200 | printf("%3d.%03dms ", diff/1000, diff%1000); |
| 201 | if (broken_router) |
| 202 | printf("(This broken router returned corrupted payload) "); |
| 203 | } |
| 204 | |
| 205 | switch (e->ee_errno) { |
| 206 | case ETIMEDOUT: |
| 207 | printf("\n"); |
| 208 | break; |
| 209 | case EMSGSIZE: |
| 210 | printf("pmtu %d\n", e->ee_info); |
| 211 | mtu = e->ee_info; |
| 212 | progress = mtu; |
| 213 | break; |
| 214 | case ECONNREFUSED: |
| 215 | printf("reached\n"); |
| 216 | hops_to = sndhops<0 ? ttl : sndhops; |
| 217 | hops_from = rethops; |
| 218 | return 0; |
| 219 | case EPROTO: |
| 220 | printf("!P\n"); |
| 221 | return 0; |
| 222 | case EHOSTUNREACH: |
| 223 | if (e->ee_origin == SO_EE_ORIGIN_ICMP && |
| 224 | e->ee_type == 11 && |
| 225 | e->ee_code == 0) { |
| 226 | if (rethops>=0) { |
| 227 | if (rethops<=64) |
| 228 | rethops = 65-rethops; |
| 229 | else if (rethops<=128) |
| 230 | rethops = 129-rethops; |
| 231 | else |
| 232 | rethops = 256-rethops; |
| 233 | if (sndhops>=0 && rethops != sndhops) |
| 234 | printf("asymm %2d ", rethops); |
| 235 | else if (sndhops<0 && rethops != ttl) |
| 236 | printf("asymm %2d ", rethops); |
| 237 | } |
| 238 | printf("\n"); |
| 239 | break; |
| 240 | } |
| 241 | printf("!H\n"); |
| 242 | return 0; |
| 243 | case ENETUNREACH: |
| 244 | printf("!N\n"); |
| 245 | return 0; |
| 246 | case EACCES: |
| 247 | printf("!A\n"); |
| 248 | return 0; |
| 249 | default: |
| 250 | printf("\n"); |
| 251 | errno = e->ee_errno; |
| 252 | perror("NET ERROR"); |
| 253 | return 0; |
| 254 | } |
| 255 | goto restart; |
| 256 | } |
| 257 | |
| 258 | int probe_ttl(int fd, int ttl) |
| 259 | { |
| 260 | int i; |
| 261 | struct probehdr *hdr = pktbuf; |
| 262 | |
| 263 | memset(pktbuf, 0, mtu); |
| 264 | restart: |
| 265 | for (i=0; i<10; i++) { |
| 266 | int res; |
| 267 | |
| 268 | hdr->ttl = ttl; |
| 269 | target.sin_port = htons(base_port + hisptr); |
| 270 | gettimeofday(&hdr->tv, NULL); |
| 271 | his[hisptr].hops = ttl; |
| 272 | his[hisptr].sendtime = hdr->tv; |
| 273 | if (sendto(fd, pktbuf, mtu-overhead, 0, (struct sockaddr*)&target, sizeof(target)) > 0) |
| 274 | break; |
| 275 | res = recverr(fd, ttl); |
| 276 | his[hisptr].hops = 0; |
| 277 | if (res==0) |
| 278 | return 0; |
| 279 | if (res > 0) |
| 280 | goto restart; |
| 281 | } |
| 282 | hisptr = (hisptr + 1)&63; |
| 283 | |
| 284 | if (i<10) { |
| 285 | data_wait(fd); |
| 286 | if (recv(fd, pktbuf, mtu, MSG_DONTWAIT) > 0) { |
| 287 | printf("%2d?: reply received 8)\n", ttl); |
| 288 | return 0; |
| 289 | } |
| 290 | return recverr(fd, ttl); |
| 291 | } |
| 292 | |
| 293 | printf("%2d: send failed\n", ttl); |
| 294 | return 0; |
| 295 | } |
| 296 | |
| 297 | static void usage(void) __attribute((noreturn)); |
| 298 | |
| 299 | static void usage(void) |
| 300 | { |
| 301 | fprintf(stderr, "Usage: tracepath [-n] [-b] [-l <len>] [-p port] <destination>\n"); |
| 302 | exit(-1); |
| 303 | } |
| 304 | |
| 305 | int |
| 306 | main(int argc, char **argv) |
| 307 | { |
| 308 | struct hostent *he; |
| 309 | int fd; |
| 310 | int on; |
| 311 | int ttl; |
| 312 | char *p; |
| 313 | int ch; |
| 314 | #ifdef USE_IDN |
| 315 | int rc; |
| 316 | setlocale(LC_ALL, ""); |
| 317 | #endif |
| 318 | |
| 319 | while ((ch = getopt(argc, argv, "nbh?l:m:p:")) != EOF) { |
| 320 | switch(ch) { |
| 321 | case 'n': |
| 322 | no_resolve = 1; |
| 323 | break; |
| 324 | case 'b': |
| 325 | show_both = 1; |
| 326 | break; |
| 327 | case 'l': |
| 328 | if ((mtu = atoi(optarg)) <= overhead) { |
| 329 | fprintf(stderr, "Error: pktlen must be > %d and <= %d.\n", |
| 330 | overhead, INT_MAX); |
| 331 | exit(1); |
| 332 | } |
| 333 | break; |
| 334 | case 'm': |
| 335 | max_hops = atoi(optarg); |
| 336 | if (max_hops < 0 || max_hops > MAX_HOPS_LIMIT) { |
| 337 | fprintf(stderr, |
| 338 | "Error: max hops must be 0 .. %d (inclusive).\n", |
| 339 | MAX_HOPS_LIMIT); |
| 340 | } |
| 341 | break; |
| 342 | case 'p': |
| 343 | base_port = atoi(optarg); |
| 344 | break; |
| 345 | default: |
| 346 | usage(); |
| 347 | } |
| 348 | } |
| 349 | |
| 350 | argc -= optind; |
| 351 | argv += optind; |
| 352 | |
| 353 | if (argc != 1) |
| 354 | usage(); |
| 355 | |
| 356 | fd = socket(AF_INET, SOCK_DGRAM, 0); |
| 357 | if (fd < 0) { |
| 358 | perror("socket"); |
| 359 | exit(1); |
| 360 | } |
| 361 | target.sin_family = AF_INET; |
| 362 | |
| 363 | /* Backward compatiblity */ |
| 364 | if (!base_port) { |
| 365 | p = strchr(argv[0], '/'); |
| 366 | if (p) { |
| 367 | *p = 0; |
| 368 | base_port = atoi(p+1); |
| 369 | } else |
| 370 | base_port = 44444; |
| 371 | } |
| 372 | |
| 373 | p = argv[0]; |
| 374 | #ifdef USE_IDN |
| 375 | rc = idna_to_ascii_lz(argv[0], &p, 0); |
| 376 | if (rc != IDNA_SUCCESS) { |
| 377 | fprintf(stderr, "IDNA encoding failed: %s\n", idna_strerror(rc)); |
| 378 | exit(2); |
| 379 | } |
| 380 | #endif |
| 381 | |
| 382 | he = gethostbyname(p); |
| 383 | if (he == NULL) { |
| 384 | herror("gethostbyname"); |
| 385 | exit(1); |
| 386 | } |
| 387 | |
| 388 | #ifdef USE_IDN |
| 389 | free(p); |
| 390 | #endif |
| 391 | |
| 392 | memcpy(&target.sin_addr, he->h_addr, 4); |
| 393 | |
| 394 | on = IP_PMTUDISC_PROBE; |
| 395 | if (setsockopt(fd, SOL_IP, IP_MTU_DISCOVER, &on, sizeof(on)) && |
| 396 | (on = IP_PMTUDISC_DO, |
| 397 | setsockopt(fd, SOL_IP, IP_MTU_DISCOVER, &on, sizeof(on)))) { |
| 398 | perror("IP_MTU_DISCOVER"); |
| 399 | exit(1); |
| 400 | } |
| 401 | on = 1; |
| 402 | if (setsockopt(fd, SOL_IP, IP_RECVERR, &on, sizeof(on))) { |
| 403 | perror("IP_RECVERR"); |
| 404 | exit(1); |
| 405 | } |
| 406 | if (setsockopt(fd, SOL_IP, IP_RECVTTL, &on, sizeof(on))) { |
| 407 | perror("IP_RECVTTL"); |
| 408 | exit(1); |
| 409 | } |
| 410 | |
| 411 | pktbuf = malloc(mtu); |
| 412 | if (!pktbuf) { |
| 413 | perror("malloc"); |
| 414 | exit(1); |
| 415 | } |
| 416 | |
| 417 | for (ttl = 1; ttl <= max_hops; ttl++) { |
| 418 | int res; |
| 419 | int i; |
| 420 | |
| 421 | on = ttl; |
| 422 | if (setsockopt(fd, SOL_IP, IP_TTL, &on, sizeof(on))) { |
| 423 | perror("IP_TTL"); |
| 424 | exit(1); |
| 425 | } |
| 426 | |
| 427 | restart: |
| 428 | for (i=0; i<3; i++) { |
| 429 | int old_mtu; |
| 430 | |
| 431 | old_mtu = mtu; |
| 432 | res = probe_ttl(fd, ttl); |
| 433 | if (mtu != old_mtu) |
| 434 | goto restart; |
| 435 | if (res == 0) |
| 436 | goto done; |
| 437 | if (res > 0) |
| 438 | break; |
| 439 | } |
| 440 | |
| 441 | if (res < 0) |
| 442 | printf("%2d: no reply\n", ttl); |
| 443 | } |
| 444 | printf(" Too many hops: pmtu %d\n", mtu); |
| 445 | done: |
| 446 | printf(" Resume: pmtu %d ", mtu); |
| 447 | if (hops_to>=0) |
| 448 | printf("hops %d ", hops_to); |
| 449 | if (hops_from>=0) |
| 450 | printf("back %d ", hops_from); |
| 451 | printf("\n"); |
| 452 | exit(0); |
| 453 | } |