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4d9ad5dc MS |
1 | /* |
2 | * Multicast Traceroute for FRRouting | |
3 | * Copyright (C) 2018 Mladen Sablic | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but | |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along | |
16 | * with this program; see the file COPYING; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | */ | |
19 | ||
20 | #ifdef __linux__ | |
21 | ||
22 | #include "pim_igmp_mtrace.h" | |
23 | ||
24 | #include "checksum.h" | |
25 | #include "mtracebis_routeget.h" | |
26 | ||
27 | #include <sys/select.h> | |
28 | #include <netinet/in.h> | |
29 | #include <arpa/inet.h> | |
30 | #include <unistd.h> | |
31 | #include <sys/types.h> | |
32 | #include <sys/time.h> | |
33 | #include <stdio.h> | |
34 | #include <stdlib.h> | |
35 | #include <string.h> | |
36 | #include <time.h> | |
37 | #include <net/if.h> | |
5b02bd3a DS |
38 | #include <unistd.h> |
39 | #include <getopt.h> | |
04a2eef3 | 40 | #include <netdb.h> |
4d9ad5dc MS |
41 | |
42 | #define MTRACEBIS_VERSION "0.1" | |
43 | #define MTRACE_TIMEOUT (5) | |
44 | ||
45 | #define IP_HDR_LEN (sizeof(struct ip)) | |
46 | #define IP_RA_LEN (4) | |
47 | #define MTRACE_BUF_LEN (MTRACE_HDR_SIZE + (MTRACE_MAX_HOPS * MTRACE_RSP_SIZE)) | |
48 | #define IP_AND_MTRACE_BUF_LEN (IP_HDR_LEN + IP_RA_LEN + MTRACE_BUF_LEN) | |
49 | ||
50 | static const char *progname; | |
51 | static void usage(void) | |
52 | { | |
53 | fprintf(stderr, "Usage : %s <multicast source>\n", progname); | |
54 | } | |
55 | static void version(void) | |
56 | { | |
57 | fprintf(stderr, "%s %s\n", progname, MTRACEBIS_VERSION); | |
58 | } | |
59 | ||
04a2eef3 MS |
60 | static void print_host(struct in_addr addr) |
61 | { | |
62 | struct hostent *h; | |
63 | ||
64 | h = gethostbyaddr(&addr, sizeof(addr), AF_INET); | |
65 | if (h == NULL) | |
66 | printf("?"); | |
67 | else | |
68 | printf("%s", h->h_name); | |
69 | printf(" (%s) ", inet_ntoa(addr)); | |
70 | } | |
71 | ||
72 | static void print_line_no(int i) | |
73 | { | |
74 | printf("%3d ", -i); | |
75 | } | |
76 | ||
77 | static const char *rtg_proto_str(enum mtrace_rtg_proto proto) | |
78 | { | |
79 | static char buf[80]; | |
80 | ||
81 | buf[0] = '\0'; | |
82 | ||
83 | switch (proto) { | |
84 | case MTRACE_RTG_PROTO_DVMRP: | |
85 | return "DVMRP"; | |
86 | case MTRACE_RTG_PROTO_MOSPF: | |
87 | return "MOSPF"; | |
88 | case MTRACE_RTG_PROTO_PIM: | |
89 | return "PIM"; | |
90 | case MTRACE_RTG_PROTO_CBT: | |
91 | return "CBT"; | |
92 | case MTRACE_RTG_PROTO_PIM_SPECIAL: | |
93 | return "PIM special"; | |
94 | case MTRACE_RTG_PROTO_PIM_STATIC: | |
95 | return "PIM static"; | |
96 | case MTRACE_RTG_PROTO_DVMRP_STATIC: | |
97 | return "DVMRP static"; | |
98 | case MTRACE_RTG_PROTO_PIM_MBGP: | |
99 | return "PIM MBGP"; | |
100 | case MTRACE_RTG_PROTO_CBT_SPECIAL: | |
101 | return "CBT special"; | |
102 | case MTRACE_RTG_PROTO_CBT_STATIC: | |
103 | return "CBT static"; | |
104 | case MTRACE_RTG_PROTO_PIM_ASSERT: | |
105 | return "PIM assert"; | |
106 | default: | |
107 | sprintf(buf, "unknown protocol (%d)", proto); | |
108 | return buf; | |
109 | } | |
110 | } | |
111 | ||
112 | static void print_rtg_proto(uint32_t rtg_proto) | |
113 | { | |
114 | printf("%s", rtg_proto_str(rtg_proto)); | |
115 | } | |
116 | ||
117 | static void print_fwd_ttl(uint32_t fwd_ttl) | |
118 | { | |
119 | printf("thresh^ %d", fwd_ttl); | |
120 | } | |
121 | ||
122 | static const char *fwd_code_str(enum mtrace_fwd_code code) | |
123 | { | |
124 | static char buf[80]; | |
125 | ||
126 | buf[0] = '\0'; | |
127 | ||
128 | switch (code) { | |
129 | case MTRACE_FWD_CODE_NO_ERROR: | |
130 | return "no error"; | |
131 | case MTRACE_FWD_CODE_WRONG_IF: | |
132 | return "wrong interface"; | |
133 | case MTRACE_FWD_CODE_PRUNE_SENT: | |
134 | return "prune sent"; | |
135 | case MTRACE_FWD_CODE_PRUNE_RCVD: | |
136 | return "prune received"; | |
137 | case MTRACE_FWD_CODE_SCOPED: | |
138 | return "scoped"; | |
139 | case MTRACE_FWD_CODE_NO_ROUTE: | |
140 | return "no route"; | |
141 | case MTRACE_FWD_CODE_WRONG_LAST_HOP: | |
142 | return "wrong last hop"; | |
143 | case MTRACE_FWD_CODE_NOT_FORWARDING: | |
144 | return "not forwarding"; | |
145 | case MTRACE_FWD_CODE_REACHED_RP: | |
146 | return "reached RP"; | |
147 | case MTRACE_FWD_CODE_RPF_IF: | |
148 | return "RPF interface"; | |
149 | case MTRACE_FWD_CODE_NO_MULTICAST: | |
150 | return "no multicast"; | |
151 | case MTRACE_FWD_CODE_INFO_HIDDEN: | |
152 | return "info hidden"; | |
153 | case MTRACE_FWD_CODE_NO_SPACE: | |
154 | return "no space"; | |
155 | case MTRACE_FWD_CODE_OLD_ROUTER: | |
156 | return "old router"; | |
157 | case MTRACE_FWD_CODE_ADMIN_PROHIB: | |
158 | return "admin. prohib."; | |
159 | default: | |
160 | sprintf(buf, "unknown fwd. code (%d)", code); | |
161 | return buf; | |
162 | } | |
163 | } | |
164 | ||
165 | static void print_fwd_code(uint32_t fwd_code) | |
166 | { | |
167 | printf("%s", fwd_code_str(fwd_code)); | |
168 | } | |
169 | ||
170 | static void print_rsp(struct igmp_mtrace_rsp *rsp) | |
171 | { | |
172 | print_host(rsp->outgoing); | |
173 | if (rsp->fwd_code == 0) { | |
174 | print_rtg_proto(rsp->rtg_proto); | |
175 | printf(" "); | |
176 | print_fwd_ttl(rsp->fwd_ttl); | |
177 | } else { | |
178 | print_fwd_code(rsp->fwd_code); | |
179 | } | |
180 | printf("\n"); | |
181 | } | |
182 | ||
183 | static void print_dest(struct igmp_mtrace *mtrace) | |
184 | { | |
185 | print_line_no(0); | |
186 | print_host(mtrace->dst_addr); | |
187 | printf("\n"); | |
188 | } | |
189 | ||
190 | static void print_summary(struct igmp_mtrace *mtrace, int hops, long msec) | |
191 | { | |
192 | int i; | |
193 | int t = 0; | |
194 | ||
195 | for (i = 0; i < hops; i++) | |
196 | t += mtrace->rsp[i].fwd_ttl; | |
197 | ||
198 | printf("Round trip time %ld ms; total ttl of %d required.\n", msec, t); | |
199 | } | |
200 | ||
201 | static void print_responses(struct igmp_mtrace *mtrace, int hops, long msec) | |
202 | { | |
203 | int i; | |
204 | ||
205 | print_dest(mtrace); | |
206 | ||
207 | for (i = 0; i < hops; i++) { | |
208 | print_line_no(i + 1); | |
209 | print_rsp(&mtrace->rsp[i]); | |
210 | } | |
211 | print_summary(mtrace, hops, msec); | |
212 | } | |
213 | ||
4d9ad5dc MS |
214 | static int send_query(int fd, struct in_addr to_addr, |
215 | struct igmp_mtrace *mtrace) | |
216 | { | |
217 | struct sockaddr_in to; | |
218 | socklen_t tolen; | |
219 | int sent; | |
220 | ||
221 | memset(&to, 0, sizeof(to)); | |
222 | to.sin_family = AF_INET; | |
223 | to.sin_addr = to_addr; | |
224 | tolen = sizeof(to); | |
225 | ||
226 | sent = sendto(fd, (char *)mtrace, sizeof(*mtrace), MSG_DONTWAIT, | |
227 | (struct sockaddr *)&to, tolen); | |
228 | ||
229 | if (sent < 1) | |
230 | return -1; | |
231 | return 0; | |
232 | } | |
233 | ||
234 | static void print_query(struct igmp_mtrace *mtrace) | |
235 | { | |
236 | char src_str[INET_ADDRSTRLEN]; | |
237 | char dst_str[INET_ADDRSTRLEN]; | |
238 | char grp_str[INET_ADDRSTRLEN]; | |
239 | ||
240 | printf("* Mtrace from %s to %s via group %s\n", | |
241 | inet_ntop(AF_INET, &mtrace->src_addr, src_str, sizeof(src_str)), | |
242 | inet_ntop(AF_INET, &mtrace->dst_addr, dst_str, sizeof(dst_str)), | |
243 | inet_ntop(AF_INET, &mtrace->grp_addr, grp_str, sizeof(grp_str))); | |
244 | } | |
245 | ||
04a2eef3 | 246 | static int recv_response(int fd, int *hops, struct igmp_mtrace *mtracer) |
4d9ad5dc MS |
247 | { |
248 | int recvd; | |
249 | char mtrace_buf[IP_AND_MTRACE_BUF_LEN]; | |
250 | struct ip *ip; | |
251 | struct igmp_mtrace *mtrace; | |
252 | int mtrace_len; | |
253 | int responses; | |
4d9ad5dc MS |
254 | u_short sum; |
255 | ||
256 | recvd = recvfrom(fd, mtrace_buf, IP_AND_MTRACE_BUF_LEN, 0, NULL, 0); | |
257 | ||
258 | if (recvd < 1) { | |
259 | fprintf(stderr, "recvfrom error: %s\n", strerror(errno)); | |
260 | return -1; | |
261 | } | |
262 | ||
263 | if (recvd < (int)sizeof(struct ip)) { | |
264 | fprintf(stderr, "no ip header\n"); | |
265 | return -1; | |
266 | } | |
267 | ||
268 | ip = (struct ip *)mtrace_buf; | |
269 | ||
270 | if (ip->ip_v != 4) { | |
271 | fprintf(stderr, "IP not version 4\n"); | |
272 | return -1; | |
273 | } | |
274 | ||
275 | sum = ip->ip_sum; | |
276 | ip->ip_sum = 0; | |
277 | ||
278 | if (sum != in_cksum(ip, ip->ip_hl * 4)) | |
279 | return -1; | |
280 | ||
281 | mtrace = (struct igmp_mtrace *)(mtrace_buf + (4 * ip->ip_hl)); | |
282 | ||
283 | mtrace_len = ntohs(ip->ip_len) - ip->ip_hl * 4; | |
284 | ||
285 | if (mtrace_len < (int)MTRACE_HDR_SIZE) | |
286 | return -1; | |
287 | ||
288 | sum = mtrace->checksum; | |
289 | mtrace->checksum = 0; | |
290 | if (sum != in_cksum(mtrace, mtrace_len)) { | |
291 | fprintf(stderr, "mtrace checksum wrong\n"); | |
292 | return -1; | |
293 | } | |
294 | ||
295 | if (mtrace->type != PIM_IGMP_MTRACE_RESPONSE) | |
296 | return -1; | |
297 | ||
298 | ||
299 | responses = mtrace_len - sizeof(struct igmp_mtrace); | |
300 | responses /= sizeof(struct igmp_mtrace_rsp); | |
301 | ||
04a2eef3 MS |
302 | if (responses > MTRACE_MAX_HOPS) { |
303 | fprintf(stderr, "mtrace too large\n"); | |
304 | return -1; | |
305 | } | |
4d9ad5dc MS |
306 | |
307 | if (hops) | |
308 | *hops = responses; | |
309 | ||
04a2eef3 MS |
310 | if (mtracer) |
311 | memcpy(mtracer, mtrace, mtrace_len); | |
4d9ad5dc MS |
312 | |
313 | return 0; | |
314 | } | |
315 | ||
04a2eef3 MS |
316 | static int wait_for_response(int fd, int *hops, struct igmp_mtrace *mtrace, |
317 | long *ret_msec) | |
4d9ad5dc MS |
318 | { |
319 | fd_set readfds; | |
320 | struct timeval timeout; | |
321 | int ret = -1; | |
322 | long msec, rmsec, tmsec; | |
323 | ||
324 | FD_ZERO(&readfds); | |
325 | FD_SET(fd, &readfds); | |
326 | ||
327 | memset(&timeout, 0, sizeof(timeout)); | |
328 | ||
329 | timeout.tv_sec = MTRACE_TIMEOUT; | |
330 | ||
331 | tmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000; | |
332 | do { | |
333 | ret = select(fd + 1, &readfds, NULL, NULL, &timeout); | |
334 | if (ret <= 0) | |
335 | return ret; | |
336 | rmsec = timeout.tv_sec * 1000 + timeout.tv_usec / 1000; | |
337 | msec = tmsec - rmsec; | |
04a2eef3 MS |
338 | } while (recv_response(fd, hops, mtrace) != 0); |
339 | ||
340 | if (ret_msec) | |
341 | *ret_msec = msec; | |
4d9ad5dc MS |
342 | |
343 | return ret; | |
344 | } | |
345 | ||
04a2eef3 MS |
346 | static bool check_end(struct igmp_mtrace *mtrace, int hops) |
347 | { | |
348 | return mtrace->src_addr.s_addr == mtrace->rsp[hops - 1].prev_hop.s_addr; | |
349 | } | |
350 | ||
4d9ad5dc MS |
351 | int main(int argc, char *const argv[]) |
352 | { | |
353 | struct in_addr mc_source; | |
354 | struct in_addr iface_addr; | |
355 | struct in_addr gw_addr; | |
356 | struct in_addr mtrace_addr; | |
357 | struct igmp_mtrace mtrace; | |
04a2eef3 | 358 | struct igmp_mtrace *mtracep; |
4d9ad5dc MS |
359 | int hops = 255; |
360 | int rhops; | |
361 | int maxhops = 255; | |
362 | int perhop = 3; | |
363 | int ifindex; | |
364 | int unicast = 1; | |
365 | int ttl = 64; | |
366 | int fd = -1; | |
367 | int ret = -1; | |
368 | int c; | |
04a2eef3 | 369 | long msec; |
4d9ad5dc MS |
370 | int i, j; |
371 | char ifname[IF_NAMESIZE]; | |
04a2eef3 | 372 | char mbuf[MTRACE_BUF_LEN]; |
4d9ad5dc MS |
373 | |
374 | mtrace_addr.s_addr = inet_addr("224.0.1.32"); | |
375 | ||
376 | uid_t uid = getuid(); | |
377 | ||
378 | if (uid != 0) { | |
379 | printf("must run as root\n"); | |
380 | exit(EXIT_FAILURE); | |
381 | } | |
382 | ||
383 | if (argc <= 0) | |
384 | progname = "mtracebis"; | |
385 | else | |
386 | progname = argv[0]; | |
387 | ||
388 | if (argc != 2) { | |
389 | usage(); | |
390 | exit(EXIT_FAILURE); | |
391 | } | |
392 | ||
393 | while (1) { | |
394 | static struct option long_options[] = { | |
395 | {"help", no_argument, 0, 'h'}, | |
396 | {"version", no_argument, 0, 'v'}, | |
996c9314 | 397 | {0, 0, 0, 0}}; |
4d9ad5dc MS |
398 | int option_index = 0; |
399 | ||
400 | c = getopt_long(argc, argv, "vh", long_options, &option_index); | |
401 | ||
402 | if (c == -1) | |
403 | break; | |
404 | ||
405 | switch (c) { | |
406 | case 'h': | |
407 | usage(); | |
408 | exit(0); | |
409 | case 'v': | |
410 | version(); | |
411 | exit(0); | |
412 | default: | |
413 | usage(); | |
414 | exit(EXIT_FAILURE); | |
415 | } | |
416 | } | |
417 | if (inet_pton(AF_INET, argv[1], &mc_source) != 1) { | |
418 | usage(); | |
419 | fprintf(stderr, "%s: %s not a valid IPv4 address\n", argv[0], | |
420 | argv[1]); | |
421 | exit(EXIT_FAILURE); | |
422 | } | |
423 | ||
424 | ifindex = routeget(mc_source, &iface_addr, &gw_addr); | |
425 | if (ifindex < 0) { | |
426 | fprintf(stderr, "%s: failed to get route to source %s\n", | |
427 | argv[0], argv[1]); | |
428 | exit(EXIT_FAILURE); | |
429 | } | |
430 | ||
431 | if (if_indextoname(ifindex, ifname) == NULL) { | |
432 | fprintf(stderr, "%s: if_indextoname error: %s\n", argv[0], | |
433 | strerror(errno)); | |
434 | exit(EXIT_FAILURE); | |
435 | } | |
436 | ||
437 | /* zero mtrace struct */ | |
438 | memset((char *)&mtrace, 0, sizeof(mtrace)); | |
439 | ||
440 | /* set up query */ | |
441 | mtrace.type = PIM_IGMP_MTRACE_QUERY_REQUEST; | |
442 | mtrace.hops = hops; | |
443 | mtrace.checksum = 0; | |
444 | mtrace.grp_addr.s_addr = 0; | |
445 | mtrace.src_addr = mc_source; | |
446 | mtrace.dst_addr = iface_addr; | |
447 | mtrace.rsp_addr = unicast ? iface_addr : mtrace_addr; | |
448 | mtrace.rsp_ttl = ttl; | |
449 | mtrace.qry_id = 0xffffff & time(NULL); | |
450 | ||
451 | mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace)); | |
452 | ||
453 | fd = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP); | |
454 | ||
455 | if (fd < 1) { | |
456 | fprintf(stderr, "%s: socket error: %s\n", argv[0], | |
457 | strerror(errno)); | |
458 | exit(EXIT_FAILURE); | |
459 | } | |
460 | ||
461 | ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname, | |
462 | strlen(ifname)); | |
463 | ||
464 | if (ret < 0) { | |
465 | fprintf(stderr, "%s: setsockopt error: %s\n", argv[0], | |
466 | strerror(errno)); | |
467 | ret = EXIT_FAILURE; | |
468 | goto close_fd; | |
469 | } | |
470 | ||
471 | print_query(&mtrace); | |
472 | if (send_query(fd, gw_addr, &mtrace) < 0) { | |
473 | fprintf(stderr, "%s: sendto error: %s\n", argv[0], | |
474 | strerror(errno)); | |
475 | ret = EXIT_FAILURE; | |
476 | goto close_fd; | |
477 | } | |
478 | printf("Querying full reverse path...\n"); | |
04a2eef3 MS |
479 | mtracep = (struct igmp_mtrace *)mbuf; |
480 | ret = wait_for_response(fd, &rhops, mtracep, &msec); | |
4d9ad5dc | 481 | if (ret > 0) { |
04a2eef3 | 482 | print_responses(mtracep, rhops, msec); |
4d9ad5dc MS |
483 | ret = 0; |
484 | goto close_fd; | |
485 | } | |
486 | if (ret < 0) { | |
487 | fprintf(stderr, "%s: select error: %s\n", argv[0], | |
488 | strerror(errno)); | |
489 | ret = EXIT_FAILURE; | |
490 | goto close_fd; | |
491 | } | |
492 | printf(" * "); | |
493 | printf("switching to hop-by-hop:\n"); | |
04a2eef3 | 494 | print_dest(&mtrace); |
4d9ad5dc | 495 | for (i = 1; i < maxhops; i++) { |
04a2eef3 | 496 | print_line_no(i); |
4d9ad5dc MS |
497 | mtrace.hops = i; |
498 | for (j = 0; j < perhop; j++) { | |
499 | mtrace.qry_id++; | |
500 | mtrace.checksum = 0; | |
501 | mtrace.checksum = in_cksum(&mtrace, sizeof(mtrace)); | |
502 | if (send_query(fd, gw_addr, &mtrace) < 0) { | |
503 | fprintf(stderr, "%s: sendto error: %s\n", | |
504 | argv[0], strerror(errno)); | |
505 | ret = EXIT_FAILURE; | |
506 | goto close_fd; | |
507 | } | |
04a2eef3 | 508 | ret = wait_for_response(fd, &rhops, mtracep, &msec); |
4d9ad5dc | 509 | if (ret > 0) { |
04a2eef3 MS |
510 | if (check_end(mtracep, rhops)) { |
511 | print_rsp(&mtracep->rsp[rhops - 1]); | |
512 | print_summary(mtracep, rhops, msec); | |
513 | ret = 0; | |
514 | goto close_fd; | |
515 | } | |
4d9ad5dc | 516 | if (i > rhops) { |
04a2eef3 | 517 | printf(" * ...giving up.\n"); |
4d9ad5dc MS |
518 | ret = 0; |
519 | goto close_fd; | |
520 | } | |
04a2eef3 | 521 | print_rsp(&mtracep->rsp[rhops - 1]); |
4d9ad5dc MS |
522 | break; |
523 | } | |
524 | printf(" *"); | |
525 | } | |
526 | if (ret <= 0) | |
527 | printf("\n"); | |
528 | } | |
529 | ret = 0; | |
530 | close_fd: | |
531 | close(fd); | |
532 | exit(ret); | |
533 | } | |
534 | ||
535 | #else /* __linux__ */ | |
536 | ||
537 | #include <stdio.h> | |
538 | #include <stdlib.h> | |
539 | ||
540 | int main(int argc, char *argv[]) | |
541 | { | |
542 | printf("%s implemented only for GNU/Linux\n", argv[0]); | |
543 | exit(0); | |
544 | } | |
545 | ||
546 | #endif /* __linux__ */ |