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4d9ad5dc MS |
1 | /* |
2 | * Multicast traceroute for FRRouting | |
3 | * Copyright (C) 2017 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 | #include <zebra.h> | |
21 | ||
22 | #include "pimd.h" | |
23 | #include "pim_util.h" | |
24 | #include "pim_sock.h" | |
25 | #include "pim_rp.h" | |
26 | #include "pim_oil.h" | |
27 | #include "pim_ifchannel.h" | |
28 | #include "pim_macro.h" | |
29 | #include "pim_igmp_mtrace.h" | |
30 | ||
31 | static void mtrace_rsp_init(struct igmp_mtrace_rsp *mtrace_rspp) | |
32 | { | |
33 | mtrace_rspp->arrival = 0; | |
34 | mtrace_rspp->incoming.s_addr = 0; | |
35 | mtrace_rspp->outgoing.s_addr = 0; | |
36 | mtrace_rspp->prev_hop.s_addr = 0; | |
37 | mtrace_rspp->in_count = MTRACE_UNKNOWN_COUNT; | |
38 | mtrace_rspp->out_count = MTRACE_UNKNOWN_COUNT; | |
39 | mtrace_rspp->total = MTRACE_UNKNOWN_COUNT; | |
40 | mtrace_rspp->rtg_proto = 0; | |
41 | mtrace_rspp->fwd_ttl = 0; | |
42 | mtrace_rspp->mbz = 0; | |
43 | mtrace_rspp->s = 0; | |
44 | mtrace_rspp->src_mask = 0; | |
45 | mtrace_rspp->fwd_code = MTRACE_FWD_CODE_NO_ERROR; | |
46 | } | |
47 | ||
48 | static void mtrace_rsp_debug(uint32_t qry_id, int rsp, | |
49 | struct igmp_mtrace_rsp *mrspp) | |
50 | { | |
51 | char inc_str[INET_ADDRSTRLEN]; | |
52 | char out_str[INET_ADDRSTRLEN]; | |
53 | char prv_str[INET_ADDRSTRLEN]; | |
54 | ||
55 | zlog_debug( | |
56 | "Rx mt(%d) qid=%ud arr=%x in=%s out=%s prev=%s proto=%d fwd=%d", | |
57 | rsp, ntohl(qry_id), mrspp->arrival, | |
58 | inet_ntop(AF_INET, &(mrspp->incoming), inc_str, | |
59 | sizeof(inc_str)), | |
60 | inet_ntop(AF_INET, &(mrspp->outgoing), out_str, | |
61 | sizeof(out_str)), | |
62 | inet_ntop(AF_INET, &(mrspp->prev_hop), prv_str, | |
63 | sizeof(prv_str)), | |
64 | mrspp->rtg_proto, mrspp->fwd_code); | |
65 | } | |
66 | ||
67 | static void mtrace_debug(struct pim_interface *pim_ifp, | |
68 | struct igmp_mtrace *mtracep, int mtrace_len) | |
69 | { | |
70 | char inc_str[INET_ADDRSTRLEN]; | |
71 | char grp_str[INET_ADDRSTRLEN]; | |
72 | char src_str[INET_ADDRSTRLEN]; | |
73 | char dst_str[INET_ADDRSTRLEN]; | |
74 | char rsp_str[INET_ADDRSTRLEN]; | |
75 | ||
76 | zlog_debug( | |
77 | "Rx mtrace packet incoming on %s: " | |
78 | "hops=%d type=%d size=%d, grp=%s, src=%s," | |
79 | " dst=%s rsp=%s ttl=%d qid=%ud", | |
80 | inet_ntop(AF_INET, &(pim_ifp->primary_address), inc_str, | |
81 | sizeof(inc_str)), | |
82 | mtracep->hops, mtracep->type, mtrace_len, | |
83 | inet_ntop(AF_INET, &(mtracep->grp_addr), grp_str, | |
84 | sizeof(grp_str)), | |
85 | inet_ntop(AF_INET, &(mtracep->src_addr), src_str, | |
86 | sizeof(src_str)), | |
87 | inet_ntop(AF_INET, &(mtracep->dst_addr), dst_str, | |
88 | sizeof(dst_str)), | |
89 | inet_ntop(AF_INET, &(mtracep->rsp_addr), rsp_str, | |
90 | sizeof(rsp_str)), | |
91 | mtracep->rsp_ttl, ntohl(mtracep->qry_id)); | |
92 | if (mtrace_len > (int)sizeof(struct igmp_mtrace)) { | |
93 | ||
94 | int i; | |
95 | ||
96 | int responses = mtrace_len - sizeof(struct igmp_mtrace); | |
97 | ||
98 | if ((responses % sizeof(struct igmp_mtrace_rsp)) != 0) | |
99 | if (PIM_DEBUG_MTRACE) | |
100 | zlog_debug( | |
101 | "Mtrace response block of wrong" | |
102 | " length"); | |
103 | ||
104 | responses = responses / sizeof(struct igmp_mtrace_rsp); | |
105 | ||
106 | for (i = 0; i < responses; i++) | |
107 | mtrace_rsp_debug(mtracep->qry_id, i, &mtracep->rsp[i]); | |
108 | } | |
109 | } | |
110 | ||
111 | /* 5.1 Query Arrival Time */ | |
112 | static uint32_t query_arrival_time(void) | |
113 | { | |
114 | struct timeval tv; | |
115 | uint32_t qat; | |
116 | ||
117 | char m_qat[] = "Query arrival time lookup failed: errno=%d: %s"; | |
118 | ||
119 | if (gettimeofday(&tv, NULL) < 0) { | |
120 | if (PIM_DEBUG_MTRACE) | |
121 | zlog_warn(m_qat, errno, safe_strerror(errno)); | |
122 | return 0; | |
123 | } | |
124 | /* not sure second offset correct, as I get different value */ | |
125 | qat = ((tv.tv_sec + 32384) << 16) + ((tv.tv_usec << 10) / 15625); | |
126 | ||
127 | return qat; | |
128 | } | |
129 | ||
130 | static int mtrace_send_packet(struct interface *ifp, | |
131 | struct igmp_mtrace *mtracep, | |
132 | size_t mtrace_buf_len, struct in_addr dst_addr, | |
133 | struct in_addr group_addr) | |
134 | { | |
135 | struct sockaddr_in to; | |
136 | struct pim_interface *pim_ifp; | |
137 | socklen_t tolen; | |
138 | ssize_t sent; | |
139 | int ret; | |
140 | int fd; | |
141 | char pim_str[INET_ADDRSTRLEN]; | |
142 | char rsp_str[INET_ADDRSTRLEN]; | |
143 | u_char ttl; | |
144 | ||
145 | pim_ifp = ifp->info; | |
146 | ||
147 | memset(&to, 0, sizeof(to)); | |
148 | to.sin_family = AF_INET; | |
149 | to.sin_addr = dst_addr; | |
150 | tolen = sizeof(to); | |
151 | ||
152 | if (PIM_DEBUG_MTRACE) | |
153 | zlog_debug("Sending mtrace packet to %s on %s", | |
154 | inet_ntop(AF_INET, &mtracep->rsp_addr, rsp_str, | |
155 | sizeof(rsp_str)), | |
156 | inet_ntop(AF_INET, &pim_ifp->primary_address, | |
157 | pim_str, sizeof(pim_str))); | |
158 | ||
159 | fd = pim_socket_raw(IPPROTO_IGMP); | |
160 | ||
161 | if (fd < 0) | |
162 | return -1; | |
163 | ||
164 | ret = pim_socket_bind(fd, ifp); | |
165 | ||
166 | if (ret < 0) { | |
167 | ret = -1; | |
168 | goto close_fd; | |
169 | } | |
170 | ||
171 | if (IPV4_CLASS_DE(ntohl(dst_addr.s_addr))) { | |
172 | if (IPV4_MC_LINKLOCAL(ntohl(dst_addr.s_addr))) { | |
173 | ttl = 1; | |
174 | } else { | |
175 | if (mtracep->type == PIM_IGMP_MTRACE_RESPONSE) | |
176 | ttl = mtracep->rsp_ttl; | |
177 | else | |
178 | ttl = 64; | |
179 | } | |
180 | ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, | |
181 | sizeof(ttl)); | |
182 | ||
183 | if (ret < 0) { | |
184 | if (PIM_DEBUG_MTRACE) | |
185 | zlog_warn("Failed to set socket multicast TTL"); | |
186 | ret = -1; | |
187 | goto close_fd; | |
188 | } | |
189 | } | |
190 | ||
191 | sent = sendto(fd, (char *)mtracep, mtrace_buf_len, MSG_DONTWAIT, | |
192 | (struct sockaddr *)&to, tolen); | |
193 | ||
194 | if (sent != (ssize_t)mtrace_buf_len) { | |
195 | char dst_str[INET_ADDRSTRLEN]; | |
196 | char group_str[INET_ADDRSTRLEN]; | |
197 | ||
198 | pim_inet4_dump("<dst?>", dst_addr, dst_str, sizeof(dst_str)); | |
199 | pim_inet4_dump("<group?>", group_addr, group_str, | |
200 | sizeof(group_str)); | |
201 | if (sent < 0) { | |
202 | if (PIM_DEBUG_MTRACE) | |
203 | zlog_warn( | |
204 | "Send mtrace request failed for %s on" | |
205 | "%s: group=%s msg_size=%zd: errno=%d: " | |
206 | " %s", | |
207 | dst_str, ifp->name, group_str, | |
208 | mtrace_buf_len, errno, | |
209 | safe_strerror(errno)); | |
210 | } else { | |
211 | if (PIM_DEBUG_MTRACE) | |
212 | zlog_warn( | |
213 | "Send mtrace request failed for %s on" | |
214 | " %s: group=%s msg_size=%zd: sent=%zd", | |
215 | dst_str, ifp->name, group_str, | |
216 | mtrace_buf_len, sent); | |
217 | } | |
218 | ret = -1; | |
219 | goto close_fd; | |
220 | } | |
221 | ret = 0; | |
222 | close_fd: | |
223 | close(fd); | |
224 | return ret; | |
225 | } | |
226 | ||
227 | static int mtrace_un_forward_packet(struct pim_instance *pim, struct ip *ip_hdr, | |
228 | struct interface *interface) | |
229 | { | |
230 | struct pim_nexthop nexthop; | |
231 | struct sockaddr_in to; | |
232 | struct interface *if_out; | |
233 | socklen_t tolen; | |
234 | int ret; | |
235 | int fd; | |
236 | int sent; | |
237 | uint16_t checksum; | |
238 | ||
239 | checksum = ip_hdr->ip_sum; | |
240 | ||
241 | ip_hdr->ip_sum = 0; | |
242 | ||
243 | if (checksum != in_cksum(ip_hdr, ip_hdr->ip_hl * 4)) | |
244 | return -1; | |
245 | ||
246 | if (ip_hdr->ip_ttl-- <= 1) | |
247 | return -1; | |
248 | ||
249 | ip_hdr->ip_sum = in_cksum(ip_hdr, ip_hdr->ip_hl * 4); | |
250 | ||
251 | fd = pim_socket_raw(IPPROTO_RAW); | |
252 | ||
253 | if (fd < 0) | |
254 | return -1; | |
255 | ||
256 | pim_socket_ip_hdr(fd); | |
257 | ||
258 | if (interface == NULL) { | |
259 | ret = pim_nexthop_lookup(pim, &nexthop, ip_hdr->ip_dst, 0); | |
260 | ||
261 | if (ret != 0) { | |
262 | if (PIM_DEBUG_MTRACE) | |
263 | zlog_warn( | |
264 | "Dropping mtrace packet, " | |
265 | "no route to destination"); | |
266 | return -1; | |
267 | } | |
268 | ||
269 | if_out = nexthop.interface; | |
270 | } else { | |
271 | if_out = interface; | |
272 | } | |
273 | ||
274 | ret = pim_socket_bind(fd, if_out); | |
275 | ||
276 | if (ret < 0) { | |
277 | close(fd); | |
278 | return -1; | |
279 | } | |
280 | ||
281 | memset(&to, 0, sizeof(to)); | |
282 | to.sin_family = AF_INET; | |
283 | to.sin_addr = ip_hdr->ip_dst; | |
284 | tolen = sizeof(to); | |
285 | ||
286 | sent = sendto(fd, ip_hdr, ntohs(ip_hdr->ip_len), 0, | |
287 | (struct sockaddr *)&to, tolen); | |
288 | ||
289 | close(fd); | |
290 | ||
291 | if (sent < 0) { | |
292 | if (PIM_DEBUG_MTRACE) | |
293 | zlog_warn( | |
294 | "Failed to forward mtrace packet:" | |
295 | " sendto errno=%d, %s", | |
296 | errno, safe_strerror(errno)); | |
297 | return -1; | |
298 | } | |
299 | ||
300 | if (PIM_DEBUG_MTRACE) { | |
301 | zlog_debug("Fwd mtrace packet len=%u to %s ttl=%u", | |
302 | ntohs(ip_hdr->ip_len), inet_ntoa(ip_hdr->ip_dst), | |
303 | ip_hdr->ip_ttl); | |
304 | } | |
305 | ||
306 | return 0; | |
307 | } | |
308 | ||
309 | static int mtrace_mc_forward_packet(struct pim_instance *pim, struct ip *ip_hdr) | |
310 | { | |
311 | struct prefix_sg sg; | |
312 | struct channel_oil *c_oil; | |
313 | struct listnode *chnode; | |
314 | struct listnode *chnextnode; | |
315 | struct pim_ifchannel *ch = NULL; | |
316 | int ret = -1; | |
317 | ||
318 | memset(&sg, 0, sizeof(struct prefix_sg)); | |
319 | sg.grp = ip_hdr->ip_dst; | |
320 | ||
321 | c_oil = pim_find_channel_oil(pim, &sg); | |
322 | ||
323 | if (c_oil == NULL) { | |
324 | if (PIM_DEBUG_MTRACE) { | |
325 | zlog_debug( | |
326 | "Dropping mtrace multicast packet " | |
327 | "len=%u to %s ttl=%u", | |
328 | ntohs(ip_hdr->ip_len), | |
329 | inet_ntoa(ip_hdr->ip_dst), ip_hdr->ip_ttl); | |
330 | } | |
331 | return -1; | |
332 | } | |
333 | if (c_oil->up == NULL) | |
334 | return -1; | |
335 | if (c_oil->up->ifchannels == NULL) | |
336 | return -1; | |
337 | for (ALL_LIST_ELEMENTS(c_oil->up->ifchannels, chnode, chnextnode, ch)) { | |
338 | if (pim_macro_chisin_oiflist(ch)) { | |
339 | int r; | |
340 | ||
341 | r = mtrace_un_forward_packet(pim, ip_hdr, | |
342 | ch->interface); | |
343 | if (r == 0) | |
344 | ret = 0; | |
345 | } | |
346 | } | |
347 | return ret; | |
348 | } | |
349 | ||
350 | ||
351 | static int mtrace_forward_packet(struct pim_instance *pim, struct ip *ip_hdr) | |
352 | { | |
353 | if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr))) | |
354 | return mtrace_mc_forward_packet(pim, ip_hdr); | |
355 | else | |
356 | return mtrace_un_forward_packet(pim, ip_hdr, NULL); | |
357 | } | |
358 | ||
359 | /* 6.5 Sending Traceroute Responses */ | |
360 | static int mtrace_send_mc_response(struct pim_instance *pim, | |
361 | struct igmp_mtrace *mtracep, | |
362 | size_t mtrace_len) | |
363 | { | |
364 | struct prefix_sg sg; | |
365 | struct channel_oil *c_oil; | |
366 | struct listnode *chnode; | |
367 | struct listnode *chnextnode; | |
368 | struct pim_ifchannel *ch = NULL; | |
369 | int ret = -1; | |
370 | ||
371 | memset(&sg, 0, sizeof(struct prefix_sg)); | |
372 | sg.grp = mtracep->rsp_addr; | |
373 | ||
374 | c_oil = pim_find_channel_oil(pim, &sg); | |
375 | ||
376 | if (c_oil == NULL) { | |
377 | if (PIM_DEBUG_MTRACE) { | |
378 | zlog_debug( | |
379 | "Dropping mtrace multicast response packet " | |
380 | "len=%u to %s", | |
381 | (unsigned int)mtrace_len, | |
382 | inet_ntoa(mtracep->rsp_addr)); | |
383 | } | |
384 | return -1; | |
385 | } | |
386 | if (c_oil->up == NULL) | |
387 | return -1; | |
388 | if (c_oil->up->ifchannels == NULL) | |
389 | return -1; | |
390 | for (ALL_LIST_ELEMENTS(c_oil->up->ifchannels, chnode, chnextnode, ch)) { | |
391 | if (pim_macro_chisin_oiflist(ch)) { | |
392 | int r; | |
393 | ||
394 | r = mtrace_send_packet(ch->interface, mtracep, | |
395 | mtrace_len, mtracep->rsp_addr, | |
396 | mtracep->grp_addr); | |
397 | if (r == 0) | |
398 | ret = 0; | |
399 | } | |
400 | } | |
401 | return ret; | |
402 | } | |
403 | ||
404 | static int mtrace_send_response(struct pim_instance *pim, | |
405 | struct igmp_mtrace *mtracep, size_t mtrace_len) | |
406 | { | |
407 | struct pim_nexthop nexthop; | |
408 | int ret; | |
409 | ||
410 | mtracep->type = PIM_IGMP_MTRACE_RESPONSE; | |
411 | ||
412 | mtracep->checksum = 0; | |
413 | mtracep->checksum = in_cksum((char *)mtracep, mtrace_len); | |
414 | ||
415 | if (IPV4_CLASS_DE(ntohl(mtracep->rsp_addr.s_addr))) { | |
416 | struct pim_rpf *p_rpf; | |
417 | char grp_str[INET_ADDRSTRLEN]; | |
418 | ||
419 | if (pim_rp_i_am_rp(pim, mtracep->rsp_addr)) | |
420 | return mtrace_send_mc_response(pim, mtracep, | |
421 | mtrace_len); | |
422 | ||
423 | p_rpf = pim_rp_g(pim, mtracep->rsp_addr); | |
424 | ||
425 | if (p_rpf == NULL) { | |
426 | if (PIM_DEBUG_MTRACE) | |
427 | zlog_warn("mtrace no RP for %s", | |
428 | inet_ntop(AF_INET, | |
429 | &(mtracep->rsp_addr), | |
430 | grp_str, sizeof(grp_str))); | |
431 | return -1; | |
432 | } | |
433 | nexthop = p_rpf->source_nexthop; | |
434 | if (PIM_DEBUG_MTRACE) | |
435 | zlog_debug("mtrace response to RP"); | |
436 | } else { | |
437 | /* TODO: should use unicast rib lookup */ | |
438 | ret = pim_nexthop_lookup(pim, &nexthop, mtracep->rsp_addr, 1); | |
439 | ||
440 | if (ret != 0) { | |
441 | if (PIM_DEBUG_MTRACE) | |
442 | zlog_warn( | |
443 | "Dropped response qid=%ud, no route to " | |
444 | "response address", | |
445 | mtracep->qry_id); | |
446 | return -1; | |
447 | } | |
448 | } | |
449 | ||
450 | return mtrace_send_packet(nexthop.interface, mtracep, mtrace_len, | |
451 | mtracep->rsp_addr, mtracep->grp_addr); | |
452 | } | |
453 | ||
454 | int igmp_mtrace_recv_qry_req(struct igmp_sock *igmp, struct ip *ip_hdr, | |
455 | struct in_addr from, const char *from_str, | |
456 | char *igmp_msg, int igmp_msg_len) | |
457 | { | |
458 | static uint32_t qry_id, qry_src; | |
459 | char mtrace_buf[MTRACE_HDR_SIZE + MTRACE_MAX_HOPS * MTRACE_RSP_SIZE]; | |
460 | struct pim_nexthop nexthop; | |
461 | struct interface *ifp; | |
462 | struct interface *out_ifp; | |
463 | struct pim_interface *pim_ifp; | |
464 | struct pim_interface *pim_out_ifp; | |
465 | struct pim_instance *pim; | |
466 | struct igmp_mtrace *mtracep; | |
467 | struct igmp_mtrace_rsp *rspp; | |
468 | struct in_addr nh_addr; | |
469 | enum mtrace_fwd_code fwd_code = MTRACE_FWD_CODE_NO_ERROR; | |
470 | int ret; | |
471 | size_t r_len; | |
472 | int last_rsp_ind = 0; | |
473 | size_t mtrace_len; | |
474 | uint16_t recv_checksum; | |
475 | uint16_t checksum; | |
476 | ||
477 | ifp = igmp->interface; | |
478 | pim_ifp = ifp->info; | |
479 | pim = pim_ifp->pim; | |
480 | ||
481 | /* | |
482 | * 6. Router Behaviour | |
483 | * Check if mtrace packet is addressed elsewhere and forward, | |
484 | * if applicable | |
485 | */ | |
486 | if (!IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr))) | |
487 | if (!if_lookup_exact_address(&ip_hdr->ip_dst, AF_INET, | |
488 | pim->vrf_id)) | |
489 | return mtrace_forward_packet(pim, ip_hdr); | |
490 | ||
491 | if (igmp_msg_len < (int)sizeof(struct igmp_mtrace)) { | |
492 | if (PIM_DEBUG_MTRACE) | |
493 | zlog_warn( | |
494 | "Recv mtrace packet from %s on %s: too short," | |
495 | " len=%d, min=%lu", | |
496 | from_str, ifp->name, igmp_msg_len, | |
497 | sizeof(struct igmp_mtrace)); | |
498 | return -1; | |
499 | } | |
500 | ||
501 | mtracep = (struct igmp_mtrace *)igmp_msg; | |
502 | ||
503 | recv_checksum = mtracep->checksum; | |
504 | ||
505 | mtracep->checksum = 0; | |
506 | ||
507 | checksum = in_cksum(igmp_msg, igmp_msg_len); | |
508 | ||
509 | if (recv_checksum != checksum) { | |
510 | if (PIM_DEBUG_MTRACE) | |
511 | zlog_warn( | |
512 | "Recv mtrace packet from %s on %s: checksum" | |
513 | " mismatch: received=%x computed=%x", | |
514 | from_str, ifp->name, recv_checksum, checksum); | |
515 | return -1; | |
516 | } | |
517 | ||
518 | if (PIM_DEBUG_MTRACE) | |
519 | mtrace_debug(pim_ifp, mtracep, igmp_msg_len); | |
520 | ||
521 | /* subtract header from message length */ | |
522 | r_len = igmp_msg_len - sizeof(struct igmp_mtrace); | |
523 | ||
524 | /* Classify mtrace packet, check if it is a query */ | |
525 | if (!r_len) { | |
526 | if (PIM_DEBUG_MTRACE) | |
527 | zlog_debug("Received IGMP multicast traceroute query"); | |
528 | ||
529 | /* 6.1.1 Packet verification */ | |
530 | if (!pim_if_connected_to_source(ifp, mtracep->dst_addr)) { | |
531 | if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr))) { | |
532 | if (PIM_DEBUG_MTRACE) | |
533 | zlog_debug( | |
534 | "Dropping multicast query " | |
535 | "on wrong interface"); | |
536 | return -1; | |
537 | } | |
538 | /* Unicast query on wrong interface */ | |
539 | fwd_code = MTRACE_FWD_CODE_WRONG_IF; | |
540 | } | |
541 | if (qry_id == mtracep->qry_id && qry_src == from.s_addr) { | |
542 | if (PIM_DEBUG_MTRACE) | |
543 | zlog_debug( | |
544 | "Dropping multicast query with " | |
545 | "duplicate source and id"); | |
546 | return -1; | |
547 | } | |
548 | qry_id = mtracep->qry_id; | |
549 | qry_src = from.s_addr; | |
550 | } | |
551 | /* if response fields length is equal to a whole number of responses */ | |
552 | else if ((r_len % sizeof(struct igmp_mtrace_rsp)) == 0) { | |
553 | r_len = igmp_msg_len - sizeof(struct igmp_mtrace); | |
554 | ||
555 | if (r_len != 0) | |
556 | last_rsp_ind = r_len / sizeof(struct igmp_mtrace_rsp); | |
557 | if (last_rsp_ind > MTRACE_MAX_HOPS) { | |
558 | if (PIM_DEBUG_MTRACE) | |
559 | zlog_warn("Mtrace request of excessive size"); | |
560 | return -1; | |
561 | } | |
562 | } else { | |
563 | if (PIM_DEBUG_MTRACE) | |
564 | zlog_warn( | |
565 | "Recv mtrace packet from %s on %s: " | |
566 | "invalid length %d", | |
567 | from_str, ifp->name, igmp_msg_len); | |
568 | return -1; | |
569 | } | |
570 | ||
571 | /* 6.2.1 Packet Verification - drop not link-local multicast */ | |
572 | if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr)) | |
573 | && !IPV4_MC_LINKLOCAL(ntohl(ip_hdr->ip_dst.s_addr))) { | |
574 | if (PIM_DEBUG_MTRACE) | |
575 | zlog_warn( | |
576 | "Recv mtrace packet from %s on %s:" | |
577 | " not link-local multicast %s", | |
578 | from_str, ifp->name, inet_ntoa(ip_hdr->ip_dst)); | |
579 | return -1; | |
580 | } | |
581 | ||
582 | /* 6.2.2. Normal Processing */ | |
583 | ||
584 | /* 6.2.2. 1. */ | |
585 | ||
586 | if (last_rsp_ind == MTRACE_MAX_HOPS) { | |
587 | mtracep->rsp[MTRACE_MAX_HOPS - 1].fwd_code = | |
588 | MTRACE_FWD_CODE_NO_SPACE; | |
589 | return mtrace_send_response(pim_ifp->pim, mtracep, | |
590 | igmp_msg_len); | |
591 | } | |
592 | ||
593 | /* calculate new mtrace mtrace lenght with extra response */ | |
594 | mtrace_len = igmp_msg_len + sizeof(struct igmp_mtrace_rsp); | |
595 | ||
596 | /* copy received query/request */ | |
597 | memcpy(mtrace_buf, igmp_msg, igmp_msg_len); | |
598 | ||
599 | /* repoint mtracep pointer to copy */ | |
600 | mtracep = (struct igmp_mtrace *)mtrace_buf; | |
601 | ||
602 | /* pointer for extra response field to be filled in */ | |
603 | rspp = &mtracep->rsp[last_rsp_ind]; | |
604 | ||
605 | /* initialize extra response field */ | |
606 | mtrace_rsp_init(rspp); | |
607 | ||
608 | rspp->arrival = htonl(query_arrival_time()); | |
609 | rspp->outgoing = pim_ifp->primary_address; | |
610 | rspp->out_count = htonl(MTRACE_UNKNOWN_COUNT); | |
611 | ||
612 | /* 6.2.2. 2. Attempt to determine forwarding information */ | |
613 | ||
614 | nh_addr.s_addr = 0; | |
615 | ||
616 | ret = pim_nexthop_lookup(pim, &nexthop, mtracep->src_addr, 1); | |
617 | ||
618 | if (ret == 0) { | |
619 | char nexthop_str[INET_ADDRSTRLEN]; | |
620 | ||
621 | if (PIM_DEBUG_MTRACE) | |
622 | zlog_debug("mtrace pim_nexthop_lookup OK"); | |
623 | ||
624 | if (PIM_DEBUG_MTRACE) | |
625 | zlog_warn("mtrace next_hop=%s", | |
626 | inet_ntop(nexthop.mrib_nexthop_addr.family, | |
627 | &nexthop.mrib_nexthop_addr.u.prefix, | |
628 | nexthop_str, sizeof(nexthop_str))); | |
629 | ||
630 | if (nexthop.mrib_nexthop_addr.family == AF_INET) | |
631 | nh_addr = nexthop.mrib_nexthop_addr.u.prefix4; | |
632 | } | |
633 | /* 6.4 Forwarding Traceroute Requests: ... Otherwise, ... */ | |
634 | else { | |
635 | if (PIM_DEBUG_MTRACE) | |
636 | zlog_debug("mtrace not found neighbor"); | |
637 | if (!fwd_code) | |
638 | rspp->fwd_code = MTRACE_FWD_CODE_NO_ROUTE; | |
639 | else | |
640 | rspp->fwd_code = fwd_code; | |
641 | /* 6.5 Sending Traceroute Responses */ | |
642 | return mtrace_send_response(pim, mtracep, mtrace_len); | |
643 | } | |
644 | ||
645 | out_ifp = nexthop.interface; | |
646 | pim_out_ifp = out_ifp->info; | |
647 | ||
648 | rspp->incoming = pim_out_ifp->primary_address; | |
649 | rspp->prev_hop = nh_addr; | |
650 | rspp->in_count = htonl(MTRACE_UNKNOWN_COUNT); | |
651 | rspp->total = htonl(MTRACE_UNKNOWN_COUNT); | |
652 | rspp->rtg_proto = MTRACE_RTG_PROTO_PIM; | |
653 | rspp->s = 1; | |
654 | rspp->src_mask = 32; | |
655 | ||
656 | if (nh_addr.s_addr == 0) { | |
657 | /* reached source? */ | |
658 | if (pim_if_connected_to_source(out_ifp, mtracep->src_addr)) | |
659 | return mtrace_send_response(pim, mtracep, mtrace_len); | |
660 | /* | |
661 | * 6.4 Forwarding Traceroute Requests: | |
662 | * Previous-hop router not known | |
663 | */ | |
664 | inet_aton(MCAST_ALL_ROUTERS, &nh_addr); | |
665 | } | |
666 | ||
667 | if (mtracep->hops <= (last_rsp_ind + 1)) | |
668 | return mtrace_send_response(pim, mtracep, mtrace_len); | |
669 | ||
670 | mtracep->checksum = 0; | |
671 | ||
672 | mtracep->checksum = in_cksum(mtrace_buf, mtrace_len); | |
673 | ||
674 | return mtrace_send_packet(out_ifp, mtracep, mtrace_len, nh_addr, | |
675 | mtracep->grp_addr); | |
676 | } | |
677 | ||
678 | int igmp_mtrace_recv_response(struct igmp_sock *igmp, struct ip *ip_hdr, | |
679 | struct in_addr from, const char *from_str, | |
680 | char *igmp_msg, int igmp_msg_len) | |
681 | { | |
682 | static uint32_t qry_id, rsp_dst; | |
683 | struct interface *ifp; | |
684 | struct pim_interface *pim_ifp; | |
685 | struct pim_instance *pim; | |
686 | struct igmp_mtrace *mtracep; | |
687 | uint16_t recv_checksum; | |
688 | uint16_t checksum; | |
689 | ||
690 | ifp = igmp->interface; | |
691 | pim_ifp = ifp->info; | |
692 | pim = pim_ifp->pim; | |
693 | ||
694 | mtracep = (struct igmp_mtrace *)igmp_msg; | |
695 | ||
696 | recv_checksum = mtracep->checksum; | |
697 | ||
698 | mtracep->checksum = 0; | |
699 | ||
700 | checksum = in_cksum(igmp_msg, igmp_msg_len); | |
701 | ||
702 | if (recv_checksum != checksum) { | |
703 | if (PIM_DEBUG_MTRACE) | |
704 | zlog_warn( | |
705 | "Recv mtrace response from %s on %s: checksum" | |
706 | " mismatch: received=%x computed=%x", | |
707 | from_str, ifp->name, recv_checksum, checksum); | |
708 | return -1; | |
709 | } | |
710 | ||
711 | mtracep->checksum = checksum; | |
712 | ||
713 | if (PIM_DEBUG_MTRACE) | |
714 | mtrace_debug(pim_ifp, mtracep, igmp_msg_len); | |
715 | ||
716 | /* Drop duplicate packets */ | |
717 | if (qry_id == mtracep->qry_id && rsp_dst == ip_hdr->ip_dst.s_addr) { | |
718 | if (PIM_DEBUG_MTRACE) | |
719 | zlog_debug("duplicate mtrace response packet dropped"); | |
720 | return -1; | |
721 | } | |
722 | ||
723 | qry_id = mtracep->qry_id; | |
724 | rsp_dst = ip_hdr->ip_dst.s_addr; | |
725 | ||
726 | return mtrace_forward_packet(pim, ip_hdr); | |
727 | } |