Line data Source code
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 : /* based on draft-ietf-idmr-traceroute-ipm-07 */
21 :
22 : #include <zebra.h>
23 :
24 : #include "pimd.h"
25 : #include "pim_instance.h"
26 : #include "pim_util.h"
27 : #include "pim_sock.h"
28 : #include "pim_rp.h"
29 : #include "pim_oil.h"
30 : #include "pim_ifchannel.h"
31 : #include "pim_macro.h"
32 : #include "pim_igmp_mtrace.h"
33 :
34 0 : static struct in_addr mtrace_primary_address(struct interface *ifp)
35 : {
36 0 : struct connected *ifc;
37 0 : struct listnode *node;
38 0 : struct in_addr any;
39 0 : struct pim_interface *pim_ifp;
40 :
41 0 : if (ifp->info) {
42 0 : pim_ifp = ifp->info;
43 0 : return pim_ifp->primary_address;
44 : }
45 :
46 0 : any.s_addr = INADDR_ANY;
47 :
48 0 : for (ALL_LIST_ELEMENTS_RO(ifp->connected, node, ifc)) {
49 0 : struct prefix *p = ifc->address;
50 :
51 0 : if (p->family != AF_INET)
52 0 : continue;
53 :
54 0 : if (!CHECK_FLAG(ifc->flags, ZEBRA_IFA_SECONDARY))
55 0 : return p->u.prefix4;
56 : /* in case no primary found, return a secondary */
57 0 : any = p->u.prefix4;
58 : }
59 0 : return any;
60 : }
61 :
62 0 : static bool mtrace_fwd_info_weak(struct pim_instance *pim,
63 : struct igmp_mtrace *mtracep,
64 : struct igmp_mtrace_rsp *rspp,
65 : struct interface **ifpp)
66 : {
67 0 : struct pim_nexthop nexthop;
68 0 : struct interface *ifp_in;
69 0 : struct in_addr nh_addr;
70 :
71 0 : nh_addr.s_addr = INADDR_ANY;
72 :
73 0 : memset(&nexthop, 0, sizeof(nexthop));
74 :
75 0 : if (!pim_nexthop_lookup(pim, &nexthop, mtracep->src_addr, 1)) {
76 0 : if (PIM_DEBUG_MTRACE)
77 0 : zlog_debug("mtrace not found neighbor");
78 0 : return false;
79 : }
80 :
81 0 : if (PIM_DEBUG_MTRACE)
82 0 : zlog_debug("mtrace pim_nexthop_lookup OK");
83 :
84 0 : if (PIM_DEBUG_MTRACE)
85 0 : zlog_debug("mtrace next_hop=%pPAs", &nexthop.mrib_nexthop_addr);
86 :
87 0 : nh_addr = nexthop.mrib_nexthop_addr;
88 :
89 0 : ifp_in = nexthop.interface;
90 :
91 : /* return interface for forwarding mtrace packets */
92 0 : *ifpp = ifp_in;
93 :
94 : /* 6.2.2. 4. Fill in the Incoming Interface Address... */
95 0 : rspp->incoming = mtrace_primary_address(ifp_in);
96 0 : rspp->prev_hop = nh_addr;
97 0 : rspp->in_count = htonl(MTRACE_UNKNOWN_COUNT);
98 0 : rspp->total = htonl(MTRACE_UNKNOWN_COUNT);
99 0 : rspp->rtg_proto = MTRACE_RTG_PROTO_PIM;
100 0 : return true;
101 : }
102 :
103 0 : static bool mtrace_fwd_info(struct pim_instance *pim,
104 : struct igmp_mtrace *mtracep,
105 : struct igmp_mtrace_rsp *rspp,
106 : struct interface **ifpp)
107 : {
108 0 : pim_sgaddr sg;
109 0 : struct pim_upstream *up;
110 0 : struct interface *ifp_in;
111 0 : struct in_addr nh_addr;
112 0 : uint32_t total;
113 :
114 0 : memset(&sg, 0, sizeof(sg));
115 0 : sg.src = mtracep->src_addr;
116 0 : sg.grp = mtracep->grp_addr;
117 :
118 0 : up = pim_upstream_find(pim, &sg);
119 :
120 0 : if (!up) {
121 0 : sg.src = PIMADDR_ANY;
122 0 : up = pim_upstream_find(pim, &sg);
123 : }
124 :
125 0 : if (!up)
126 : return false;
127 :
128 0 : if (!up->rpf.source_nexthop.interface) {
129 0 : if (PIM_DEBUG_TRACE)
130 0 : zlog_debug("%s: up %s RPF is not present", __func__,
131 : up->sg_str);
132 0 : return false;
133 : }
134 :
135 0 : ifp_in = up->rpf.source_nexthop.interface;
136 0 : nh_addr = up->rpf.source_nexthop.mrib_nexthop_addr;
137 0 : total = htonl(MTRACE_UNKNOWN_COUNT);
138 :
139 0 : if (PIM_DEBUG_MTRACE)
140 0 : zlog_debug("fwd_info: upstream next hop=%pI4", &nh_addr);
141 :
142 0 : if (up->channel_oil)
143 0 : total = up->channel_oil->cc.pktcnt;
144 :
145 : /* return interface for forwarding mtrace packets */
146 0 : *ifpp = ifp_in;
147 :
148 : /* 6.2.2. 4. Fill in the Incoming Interface Address... */
149 0 : rspp->incoming = mtrace_primary_address(ifp_in);
150 0 : rspp->prev_hop = nh_addr;
151 0 : rspp->in_count = htonl(MTRACE_UNKNOWN_COUNT);
152 0 : rspp->total = total;
153 0 : rspp->rtg_proto = MTRACE_RTG_PROTO_PIM;
154 :
155 : /* 6.2.2. 4. Fill in ... S, and Src Mask */
156 0 : if (!pim_addr_is_any(sg.src)) {
157 0 : rspp->s = 1;
158 0 : rspp->src_mask = MTRACE_SRC_MASK_SOURCE;
159 : } else {
160 0 : rspp->s = 0;
161 0 : rspp->src_mask = MTRACE_SRC_MASK_GROUP;
162 : }
163 :
164 : return true;
165 : }
166 :
167 0 : static void mtrace_rsp_set_fwd_code(struct igmp_mtrace_rsp *mtrace_rspp,
168 : enum mtrace_fwd_code fwd_code)
169 : {
170 0 : if (mtrace_rspp->fwd_code == MTRACE_FWD_CODE_NO_ERROR)
171 0 : mtrace_rspp->fwd_code = fwd_code;
172 : }
173 :
174 0 : static void mtrace_rsp_init(struct igmp_mtrace_rsp *mtrace_rspp)
175 : {
176 0 : mtrace_rspp->arrival = 0;
177 0 : mtrace_rspp->incoming.s_addr = INADDR_ANY;
178 0 : mtrace_rspp->outgoing.s_addr = INADDR_ANY;
179 0 : mtrace_rspp->prev_hop.s_addr = INADDR_ANY;
180 0 : mtrace_rspp->in_count = htonl(MTRACE_UNKNOWN_COUNT);
181 0 : mtrace_rspp->out_count = htonl(MTRACE_UNKNOWN_COUNT);
182 0 : mtrace_rspp->total = htonl(MTRACE_UNKNOWN_COUNT);
183 0 : mtrace_rspp->rtg_proto = 0;
184 0 : mtrace_rspp->fwd_ttl = 0;
185 0 : mtrace_rspp->mbz = 0;
186 0 : mtrace_rspp->s = 0;
187 0 : mtrace_rspp->src_mask = 0;
188 0 : mtrace_rspp->fwd_code = MTRACE_FWD_CODE_NO_ERROR;
189 : }
190 :
191 0 : static void mtrace_rsp_debug(uint32_t qry_id, int rsp,
192 : struct igmp_mtrace_rsp *mrspp)
193 : {
194 0 : struct in_addr incoming = mrspp->incoming;
195 0 : struct in_addr outgoing = mrspp->outgoing;
196 0 : struct in_addr prev_hop = mrspp->prev_hop;
197 :
198 0 : zlog_debug(
199 : "Rx mt(%d) qid=%ud arr=%x in=%pI4 out=%pI4 prev=%pI4 proto=%d fwd=%d",
200 : rsp, ntohl(qry_id), mrspp->arrival, &incoming, &outgoing,
201 : &prev_hop, mrspp->rtg_proto, mrspp->fwd_code);
202 0 : }
203 :
204 0 : static void mtrace_debug(struct pim_interface *pim_ifp,
205 : struct igmp_mtrace *mtracep, int mtrace_len)
206 : {
207 0 : struct in_addr ga, sa, da, ra;
208 :
209 0 : ga = mtracep->grp_addr;
210 0 : sa = mtracep->src_addr;
211 0 : da = mtracep->dst_addr;
212 0 : ra = mtracep->rsp_addr;
213 :
214 0 : zlog_debug(
215 : "Rx mtrace packet incoming on %pI4: hops=%d type=%d size=%d, grp=%pI4, src=%pI4, dst=%pI4 rsp=%pI4 ttl=%d qid=%ud",
216 : &pim_ifp->primary_address, mtracep->hops, mtracep->type,
217 : mtrace_len, &ga, &sa, &da, &ra, mtracep->rsp_ttl,
218 : ntohl(mtracep->qry_id));
219 0 : if (mtrace_len > (int)sizeof(struct igmp_mtrace)) {
220 :
221 0 : int i;
222 :
223 0 : int responses = mtrace_len - sizeof(struct igmp_mtrace);
224 :
225 0 : if ((responses % sizeof(struct igmp_mtrace_rsp)) != 0)
226 0 : if (PIM_DEBUG_MTRACE)
227 0 : zlog_debug(
228 : "Mtrace response block of wrong length");
229 :
230 0 : responses = responses / sizeof(struct igmp_mtrace_rsp);
231 :
232 0 : for (i = 0; i < responses; i++)
233 0 : mtrace_rsp_debug(mtracep->qry_id, i, &mtracep->rsp[i]);
234 : }
235 0 : }
236 :
237 : /* 5.1 Query Arrival Time */
238 0 : static uint32_t query_arrival_time(void)
239 : {
240 0 : struct timeval tv;
241 0 : uint32_t qat;
242 :
243 0 : if (gettimeofday(&tv, NULL) < 0) {
244 0 : if (PIM_DEBUG_MTRACE)
245 0 : zlog_debug("Query arrival time lookup failed: errno=%d: %s",
246 : errno, safe_strerror(errno));
247 0 : return 0;
248 : }
249 : /* not sure second offset correct, as I get different value */
250 0 : qat = ((tv.tv_sec + 32384) << 16) + ((tv.tv_usec << 10) / 15625);
251 :
252 0 : return qat;
253 : }
254 :
255 0 : static int mtrace_send_packet(struct interface *ifp,
256 : struct igmp_mtrace *mtracep,
257 : size_t mtrace_buf_len, struct in_addr dst_addr,
258 : struct in_addr group_addr)
259 : {
260 0 : struct sockaddr_in to;
261 0 : socklen_t tolen;
262 0 : ssize_t sent;
263 0 : int ret;
264 0 : int fd;
265 0 : uint8_t ttl;
266 :
267 0 : memset(&to, 0, sizeof(to));
268 0 : to.sin_family = AF_INET;
269 0 : to.sin_addr = dst_addr;
270 0 : tolen = sizeof(to);
271 :
272 0 : if (PIM_DEBUG_MTRACE) {
273 0 : struct in_addr if_addr;
274 0 : struct in_addr rsp_addr = mtracep->rsp_addr;
275 :
276 0 : if_addr = mtrace_primary_address(ifp);
277 0 : zlog_debug("Sending mtrace packet to %pI4 on %pI4", &rsp_addr,
278 : &if_addr);
279 : }
280 :
281 0 : fd = pim_socket_raw(IPPROTO_IGMP);
282 :
283 0 : if (fd < 0)
284 : return -1;
285 :
286 0 : ret = pim_socket_bind(fd, ifp);
287 :
288 0 : if (ret < 0) {
289 0 : ret = -1;
290 0 : goto close_fd;
291 : }
292 :
293 0 : if (IPV4_CLASS_DE(ntohl(dst_addr.s_addr))) {
294 0 : if (IPV4_MC_LINKLOCAL(ntohl(dst_addr.s_addr))) {
295 0 : ttl = 1;
296 : } else {
297 0 : if (mtracep->type == PIM_IGMP_MTRACE_RESPONSE)
298 0 : ttl = mtracep->rsp_ttl;
299 : else
300 0 : ttl = 64;
301 : }
302 0 : ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl,
303 : sizeof(ttl));
304 :
305 0 : if (ret < 0) {
306 0 : if (PIM_DEBUG_MTRACE)
307 0 : zlog_debug("Failed to set socket multicast TTL");
308 0 : ret = -1;
309 0 : goto close_fd;
310 : }
311 : }
312 :
313 0 : sent = sendto(fd, (char *)mtracep, mtrace_buf_len, MSG_DONTWAIT,
314 : (struct sockaddr *)&to, tolen);
315 :
316 0 : if (sent != (ssize_t)mtrace_buf_len) {
317 0 : char dst_str[INET_ADDRSTRLEN];
318 0 : char group_str[INET_ADDRSTRLEN];
319 :
320 0 : pim_inet4_dump("<dst?>", dst_addr, dst_str, sizeof(dst_str));
321 0 : pim_inet4_dump("<group?>", group_addr, group_str,
322 : sizeof(group_str));
323 0 : if (sent < 0) {
324 0 : if (PIM_DEBUG_MTRACE)
325 0 : zlog_debug(
326 : "Send mtrace request failed for %s on%s: group=%s msg_size=%zd: errno=%d: %s",
327 : dst_str, ifp->name, group_str,
328 : mtrace_buf_len, errno,
329 : safe_strerror(errno));
330 : } else {
331 0 : if (PIM_DEBUG_MTRACE)
332 0 : zlog_debug(
333 : "Send mtrace request failed for %s on %s: group=%s msg_size=%zd: sent=%zd",
334 : dst_str, ifp->name, group_str,
335 : mtrace_buf_len, sent);
336 : }
337 0 : ret = -1;
338 0 : goto close_fd;
339 : }
340 : ret = 0;
341 0 : close_fd:
342 0 : close(fd);
343 0 : return ret;
344 : }
345 :
346 0 : static int mtrace_un_forward_packet(struct pim_instance *pim, struct ip *ip_hdr,
347 : struct interface *interface)
348 : {
349 0 : struct pim_nexthop nexthop;
350 0 : struct sockaddr_in to;
351 0 : struct interface *if_out;
352 0 : socklen_t tolen;
353 0 : int ret;
354 0 : int fd;
355 0 : int sent;
356 0 : uint16_t checksum;
357 :
358 0 : checksum = ip_hdr->ip_sum;
359 :
360 0 : ip_hdr->ip_sum = 0;
361 :
362 0 : if (checksum != in_cksum(ip_hdr, ip_hdr->ip_hl * 4))
363 : return -1;
364 :
365 0 : if (ip_hdr->ip_ttl-- <= 1)
366 : return -1;
367 :
368 0 : if (interface == NULL) {
369 0 : memset(&nexthop, 0, sizeof(nexthop));
370 0 : if (!pim_nexthop_lookup(pim, &nexthop, ip_hdr->ip_dst, 0)) {
371 0 : if (PIM_DEBUG_MTRACE)
372 0 : zlog_debug(
373 : "Dropping mtrace packet, no route to destination");
374 0 : return -1;
375 : }
376 :
377 0 : if_out = nexthop.interface;
378 : } else {
379 : if_out = interface;
380 : }
381 :
382 0 : ip_hdr->ip_sum = in_cksum(ip_hdr, ip_hdr->ip_hl * 4);
383 :
384 0 : fd = pim_socket_raw(IPPROTO_RAW);
385 :
386 0 : if (fd < 0)
387 : return -1;
388 :
389 0 : pim_socket_ip_hdr(fd);
390 :
391 0 : ret = pim_socket_bind(fd, if_out);
392 :
393 0 : if (ret < 0) {
394 0 : close(fd);
395 0 : return -1;
396 : }
397 :
398 0 : memset(&to, 0, sizeof(to));
399 0 : to.sin_family = AF_INET;
400 0 : to.sin_addr = ip_hdr->ip_dst;
401 0 : tolen = sizeof(to);
402 :
403 0 : sent = sendto(fd, ip_hdr, ntohs(ip_hdr->ip_len), 0,
404 : (struct sockaddr *)&to, tolen);
405 :
406 0 : close(fd);
407 :
408 0 : if (sent < 0) {
409 0 : if (PIM_DEBUG_MTRACE)
410 0 : zlog_debug(
411 : "Failed to forward mtrace packet: sendto errno=%d, %s",
412 : errno, safe_strerror(errno));
413 0 : return -1;
414 : }
415 :
416 0 : if (PIM_DEBUG_MTRACE) {
417 0 : zlog_debug("Fwd mtrace packet len=%u to %pI4 ttl=%u",
418 : ntohs(ip_hdr->ip_len), &ip_hdr->ip_dst,
419 : ip_hdr->ip_ttl);
420 : }
421 :
422 : return 0;
423 : }
424 :
425 0 : static int mtrace_mc_forward_packet(struct pim_instance *pim, struct ip *ip_hdr)
426 : {
427 0 : pim_sgaddr sg;
428 0 : struct channel_oil *c_oil;
429 0 : struct listnode *chnode;
430 0 : struct listnode *chnextnode;
431 0 : struct pim_ifchannel *ch = NULL;
432 0 : int ret = -1;
433 :
434 0 : memset(&sg, 0, sizeof(sg));
435 0 : sg.grp = ip_hdr->ip_dst;
436 :
437 0 : c_oil = pim_find_channel_oil(pim, &sg);
438 :
439 0 : if (c_oil == NULL) {
440 0 : if (PIM_DEBUG_MTRACE) {
441 0 : zlog_debug(
442 : "Dropping mtrace multicast packet len=%u to %pI4 ttl=%u",
443 : ntohs(ip_hdr->ip_len),
444 : &ip_hdr->ip_dst, ip_hdr->ip_ttl);
445 : }
446 0 : return -1;
447 : }
448 0 : if (c_oil->up == NULL)
449 : return -1;
450 0 : if (c_oil->up->ifchannels == NULL)
451 : return -1;
452 0 : for (ALL_LIST_ELEMENTS(c_oil->up->ifchannels, chnode, chnextnode, ch)) {
453 0 : if (pim_macro_chisin_oiflist(ch)) {
454 0 : int r;
455 :
456 0 : r = mtrace_un_forward_packet(pim, ip_hdr,
457 : ch->interface);
458 0 : if (r == 0)
459 0 : ret = 0;
460 : }
461 : }
462 : return ret;
463 : }
464 :
465 :
466 0 : static int mtrace_forward_packet(struct pim_instance *pim, struct ip *ip_hdr)
467 : {
468 0 : if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr)))
469 0 : return mtrace_mc_forward_packet(pim, ip_hdr);
470 : else
471 0 : return mtrace_un_forward_packet(pim, ip_hdr, NULL);
472 : }
473 :
474 0 : static int mtrace_send_mc_response(struct pim_instance *pim,
475 : struct igmp_mtrace *mtracep,
476 : size_t mtrace_len)
477 : {
478 0 : pim_sgaddr sg;
479 0 : struct channel_oil *c_oil;
480 0 : struct listnode *chnode;
481 0 : struct listnode *chnextnode;
482 0 : struct pim_ifchannel *ch = NULL;
483 0 : int ret = -1;
484 :
485 0 : memset(&sg, 0, sizeof(sg));
486 0 : sg.grp = mtracep->rsp_addr;
487 :
488 0 : c_oil = pim_find_channel_oil(pim, &sg);
489 :
490 0 : if (c_oil == NULL) {
491 0 : if (PIM_DEBUG_MTRACE) {
492 0 : struct in_addr rsp_addr = mtracep->rsp_addr;
493 :
494 0 : zlog_debug(
495 : "Dropping mtrace multicast response packet len=%u to %pI4",
496 : (unsigned int)mtrace_len, &rsp_addr);
497 : }
498 0 : return -1;
499 : }
500 0 : if (c_oil->up == NULL)
501 : return -1;
502 0 : if (c_oil->up->ifchannels == NULL)
503 : return -1;
504 0 : for (ALL_LIST_ELEMENTS(c_oil->up->ifchannels, chnode, chnextnode, ch)) {
505 0 : if (pim_macro_chisin_oiflist(ch)) {
506 0 : int r;
507 :
508 0 : r = mtrace_send_packet(ch->interface, mtracep,
509 : mtrace_len, mtracep->rsp_addr,
510 : mtracep->grp_addr);
511 0 : if (r == 0)
512 0 : ret = 0;
513 : }
514 : }
515 : return ret;
516 : }
517 :
518 : /* 6.5 Sending Traceroute Responses */
519 0 : static int mtrace_send_response(struct pim_instance *pim,
520 : struct igmp_mtrace *mtracep, size_t mtrace_len)
521 : {
522 0 : struct pim_nexthop nexthop;
523 :
524 0 : mtracep->type = PIM_IGMP_MTRACE_RESPONSE;
525 :
526 0 : mtracep->checksum = 0;
527 0 : mtracep->checksum = in_cksum((char *)mtracep, mtrace_len);
528 :
529 0 : if (IPV4_CLASS_DE(ntohl(mtracep->rsp_addr.s_addr))) {
530 0 : struct pim_rpf *p_rpf;
531 :
532 0 : if (pim_rp_i_am_rp(pim, mtracep->rsp_addr))
533 0 : return mtrace_send_mc_response(pim, mtracep,
534 : mtrace_len);
535 :
536 0 : p_rpf = pim_rp_g(pim, mtracep->rsp_addr);
537 :
538 0 : if (p_rpf == NULL) {
539 0 : if (PIM_DEBUG_MTRACE) {
540 0 : struct in_addr rsp_addr = mtracep->rsp_addr;
541 :
542 0 : zlog_debug("mtrace no RP for %pI4", &rsp_addr);
543 : }
544 0 : return -1;
545 : }
546 0 : nexthop = p_rpf->source_nexthop;
547 0 : if (PIM_DEBUG_MTRACE)
548 0 : zlog_debug("mtrace response to RP");
549 : } else {
550 0 : memset(&nexthop, 0, sizeof(nexthop));
551 : /* TODO: should use unicast rib lookup */
552 0 : if (!pim_nexthop_lookup(pim, &nexthop, mtracep->rsp_addr, 1)) {
553 0 : if (PIM_DEBUG_MTRACE)
554 0 : zlog_debug(
555 : "Dropped response qid=%ud, no route to response address",
556 : mtracep->qry_id);
557 0 : return -1;
558 : }
559 : }
560 :
561 0 : return mtrace_send_packet(nexthop.interface, mtracep, mtrace_len,
562 : mtracep->rsp_addr, mtracep->grp_addr);
563 : }
564 :
565 0 : int igmp_mtrace_recv_qry_req(struct gm_sock *igmp, struct ip *ip_hdr,
566 : struct in_addr from, const char *from_str,
567 : char *igmp_msg, int igmp_msg_len)
568 : {
569 0 : static uint32_t qry_id, qry_src;
570 0 : char mtrace_buf[MTRACE_HDR_SIZE + MTRACE_MAX_HOPS * MTRACE_RSP_SIZE];
571 0 : struct interface *ifp;
572 0 : struct interface *out_ifp = NULL;
573 0 : struct pim_interface *pim_ifp;
574 0 : struct pim_instance *pim;
575 0 : struct igmp_mtrace *mtracep;
576 0 : struct igmp_mtrace_rsp *rspp;
577 0 : struct in_addr nh_addr;
578 0 : enum mtrace_fwd_code fwd_code = MTRACE_FWD_CODE_NO_ERROR;
579 0 : size_t r_len;
580 0 : int last_rsp_ind = 0;
581 0 : size_t mtrace_len;
582 0 : uint16_t recv_checksum;
583 0 : uint16_t checksum;
584 0 : bool reached_source;
585 0 : bool fwd_info;
586 :
587 0 : ifp = igmp->interface;
588 0 : pim_ifp = ifp->info;
589 0 : pim = pim_ifp->pim;
590 :
591 : /*
592 : * 6. Router Behaviour
593 : * Check if mtrace packet is addressed elsewhere and forward,
594 : * if applicable
595 : */
596 0 : if (!IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr)))
597 0 : if (!if_address_is_local(&ip_hdr->ip_dst, AF_INET,
598 0 : pim->vrf->vrf_id))
599 0 : return mtrace_forward_packet(pim, ip_hdr);
600 :
601 0 : if (igmp_msg_len < (int)sizeof(struct igmp_mtrace)) {
602 0 : if (PIM_DEBUG_MTRACE)
603 0 : zlog_debug(
604 : "Recv mtrace packet from %s on %s: too short, len=%d, min=%zu",
605 : from_str, ifp->name, igmp_msg_len,
606 : sizeof(struct igmp_mtrace));
607 0 : return -1;
608 : }
609 :
610 0 : mtracep = (struct igmp_mtrace *)igmp_msg;
611 :
612 0 : recv_checksum = mtracep->checksum;
613 :
614 0 : mtracep->checksum = 0;
615 :
616 0 : checksum = in_cksum(igmp_msg, igmp_msg_len);
617 :
618 0 : if (recv_checksum != checksum) {
619 0 : if (PIM_DEBUG_MTRACE)
620 0 : zlog_debug(
621 : "Recv mtrace packet from %s on %s: checksum mismatch: received=%x computed=%x",
622 : from_str, ifp->name, recv_checksum, checksum);
623 0 : return -1;
624 : }
625 :
626 : /* Collecting IGMP Rx stats */
627 0 : igmp->igmp_stats.mtrace_req++;
628 :
629 0 : if (PIM_DEBUG_MTRACE)
630 0 : mtrace_debug(pim_ifp, mtracep, igmp_msg_len);
631 :
632 : /* subtract header from message length */
633 0 : r_len = igmp_msg_len - sizeof(struct igmp_mtrace);
634 :
635 : /* Classify mtrace packet, check if it is a query */
636 0 : if (!r_len) {
637 0 : if (PIM_DEBUG_MTRACE)
638 0 : zlog_debug("Received IGMP multicast traceroute query");
639 :
640 : /* 6.1.1 Packet verification */
641 0 : if (!pim_if_connected_to_source(ifp, mtracep->dst_addr)) {
642 0 : if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr))) {
643 0 : if (PIM_DEBUG_MTRACE)
644 0 : zlog_debug(
645 : "Dropping multicast query on wrong interface");
646 0 : return -1;
647 : }
648 : /* Unicast query on wrong interface */
649 0 : fwd_code = MTRACE_FWD_CODE_WRONG_IF;
650 0 : if (PIM_DEBUG_MTRACE)
651 0 : zlog_debug("Multicast query on wrong interface");
652 : }
653 0 : if (qry_id == mtracep->qry_id && qry_src == from.s_addr) {
654 0 : if (PIM_DEBUG_MTRACE)
655 0 : zlog_debug(
656 : "Dropping multicast query with duplicate source and id");
657 0 : return -1;
658 : }
659 0 : qry_id = mtracep->qry_id;
660 0 : qry_src = from.s_addr;
661 : }
662 : /* if response fields length is equal to a whole number of responses */
663 0 : else if ((r_len % sizeof(struct igmp_mtrace_rsp)) == 0) {
664 0 : r_len = igmp_msg_len - sizeof(struct igmp_mtrace);
665 :
666 0 : if (r_len != 0)
667 0 : last_rsp_ind = r_len / sizeof(struct igmp_mtrace_rsp);
668 0 : if (last_rsp_ind > MTRACE_MAX_HOPS) {
669 0 : if (PIM_DEBUG_MTRACE)
670 0 : zlog_debug("Mtrace request of excessive size");
671 0 : return -1;
672 : }
673 : } else {
674 0 : if (PIM_DEBUG_MTRACE)
675 0 : zlog_debug(
676 : "Recv mtrace packet from %s on %s: invalid length %d",
677 : from_str, ifp->name, igmp_msg_len);
678 0 : return -1;
679 : }
680 :
681 : /* 6.2.1 Packet Verification - drop not link-local multicast */
682 0 : if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr))
683 0 : && !IPV4_MC_LINKLOCAL(ntohl(ip_hdr->ip_dst.s_addr))) {
684 0 : if (PIM_DEBUG_MTRACE)
685 0 : zlog_debug(
686 : "Recv mtrace packet from %s on %s: not link-local multicast %pI4",
687 : from_str, ifp->name, &ip_hdr->ip_dst);
688 0 : return -1;
689 : }
690 :
691 : /* 6.2.2. Normal Processing */
692 :
693 : /* 6.2.2. 1. If there is room in the current buffer? */
694 :
695 0 : if (last_rsp_ind == MTRACE_MAX_HOPS) {
696 : /* ...there was no room... */
697 0 : mtracep->rsp[MTRACE_MAX_HOPS - 1].fwd_code =
698 : MTRACE_FWD_CODE_NO_SPACE;
699 0 : return mtrace_send_response(pim_ifp->pim, mtracep,
700 : igmp_msg_len);
701 : }
702 :
703 : /* ...insert new response block... */
704 :
705 : /* calculate new mtrace lenght with extra response */
706 0 : mtrace_len = igmp_msg_len + sizeof(struct igmp_mtrace_rsp);
707 :
708 : /* copy received query/request */
709 0 : memcpy(mtrace_buf, igmp_msg, igmp_msg_len);
710 :
711 : /* repoint mtracep pointer to copy */
712 0 : mtracep = (struct igmp_mtrace *)mtrace_buf;
713 :
714 : /* pointer for extra response field to be filled in */
715 0 : rspp = &mtracep->rsp[last_rsp_ind];
716 :
717 : /* initialize extra response field */
718 0 : mtrace_rsp_init(rspp);
719 :
720 : /* carry over any error noted when receiving the query */
721 0 : rspp->fwd_code = fwd_code;
722 :
723 : /* ...and fill in Query Arrival Time... */
724 0 : rspp->arrival = htonl(query_arrival_time());
725 0 : rspp->outgoing = pim_ifp->primary_address;
726 0 : rspp->out_count = htonl(MTRACE_UNKNOWN_COUNT);
727 0 : rspp->fwd_ttl = 1;
728 :
729 : /* 6.2.2. 2. Attempt to determine the forwarding information... */
730 :
731 0 : if (mtracep->grp_addr.s_addr != INADDR_ANY)
732 0 : fwd_info = mtrace_fwd_info(pim, mtracep, rspp, &out_ifp);
733 : else
734 0 : fwd_info = mtrace_fwd_info_weak(pim, mtracep, rspp, &out_ifp);
735 :
736 : /* 6.2.2 3. If no forwarding information... */
737 0 : if (!fwd_info) {
738 0 : if (PIM_DEBUG_MTRACE)
739 0 : zlog_debug("mtrace not found multicast state");
740 0 : mtrace_rsp_set_fwd_code(rspp, MTRACE_FWD_CODE_NO_ROUTE);
741 : /* 6.2.2. 3. forward the packet to requester */
742 0 : return mtrace_send_response(pim, mtracep, mtrace_len);
743 : }
744 :
745 0 : nh_addr = rspp->prev_hop;
746 :
747 0 : reached_source = false;
748 :
749 0 : if (nh_addr.s_addr == INADDR_ANY) {
750 : /* no pim? i.e. 7.5.3. No Previous Hop */
751 0 : if (!out_ifp->info) {
752 0 : if (PIM_DEBUG_MTRACE)
753 0 : zlog_debug("mtrace not found incoming if w/ pim");
754 0 : mtrace_rsp_set_fwd_code(rspp,
755 : MTRACE_FWD_CODE_NO_MULTICAST);
756 0 : return mtrace_send_response(pim, mtracep, mtrace_len);
757 : }
758 : /* reached source? i.e. 7.5.1 Arriving at source */
759 0 : if (pim_if_connected_to_source(out_ifp, mtracep->src_addr)) {
760 0 : reached_source = true;
761 0 : rspp->prev_hop = mtracep->src_addr;
762 : }
763 : /*
764 : * 6.4 Forwarding Traceroute Requests:
765 : * Previous-hop router not known,
766 : * packet is sent to an appropriate multicast address
767 : */
768 0 : (void)inet_aton(MCAST_ALL_ROUTERS, &nh_addr);
769 : }
770 :
771 : /* 6.2.2 8. If this router is the Rendez-vous Point */
772 0 : if (mtracep->grp_addr.s_addr != INADDR_ANY &&
773 0 : pim_rp_i_am_rp(pim, mtracep->grp_addr)) {
774 0 : mtrace_rsp_set_fwd_code(rspp, MTRACE_FWD_CODE_REACHED_RP);
775 : /* 7.7.1. PIM-SM ...RP has not performed source-specific join */
776 0 : if (rspp->src_mask == MTRACE_SRC_MASK_GROUP)
777 0 : return mtrace_send_response(pim, mtracep, mtrace_len);
778 : }
779 :
780 : /*
781 : * 6.4 Forwarding Traceroute Requests: the number of response
782 : * blocks exceeds number of responses, so forward to the requester.
783 : */
784 0 : if (mtracep->hops <= (last_rsp_ind + 1))
785 0 : return mtrace_send_response(pim, mtracep, mtrace_len);
786 :
787 : /* 7.5.1. Arriving at source: terminate trace */
788 0 : if (reached_source)
789 0 : return mtrace_send_response(pim, mtracep, mtrace_len);
790 :
791 0 : mtracep->checksum = 0;
792 :
793 0 : mtracep->checksum = in_cksum(mtrace_buf, mtrace_len);
794 :
795 : /* 6.4 Forwarding Traceroute Requests: response blocks less than req. */
796 0 : return mtrace_send_packet(out_ifp, mtracep, mtrace_len, nh_addr,
797 : mtracep->grp_addr);
798 : }
799 :
800 : /* 6.3. Traceroute responses */
801 0 : int igmp_mtrace_recv_response(struct gm_sock *igmp, struct ip *ip_hdr,
802 : struct in_addr from, const char *from_str,
803 : char *igmp_msg, int igmp_msg_len)
804 : {
805 0 : static uint32_t qry_id, rsp_dst;
806 0 : struct interface *ifp;
807 0 : struct pim_interface *pim_ifp;
808 0 : struct pim_instance *pim;
809 0 : struct igmp_mtrace *mtracep;
810 0 : uint16_t recv_checksum;
811 0 : uint16_t checksum;
812 :
813 0 : ifp = igmp->interface;
814 0 : pim_ifp = ifp->info;
815 0 : pim = pim_ifp->pim;
816 :
817 0 : if (igmp_msg_len < (int)sizeof(struct igmp_mtrace)) {
818 0 : if (PIM_DEBUG_MTRACE)
819 0 : zlog_debug(
820 : "Recv mtrace packet from %s on %s: too short, len=%d, min=%zu",
821 : from_str, ifp->name, igmp_msg_len,
822 : sizeof(struct igmp_mtrace));
823 0 : return -1;
824 : }
825 :
826 0 : mtracep = (struct igmp_mtrace *)igmp_msg;
827 :
828 0 : recv_checksum = mtracep->checksum;
829 :
830 0 : mtracep->checksum = 0;
831 :
832 0 : checksum = in_cksum(igmp_msg, igmp_msg_len);
833 :
834 0 : if (recv_checksum != checksum) {
835 0 : if (PIM_DEBUG_MTRACE)
836 0 : zlog_debug(
837 : "Recv mtrace response from %s on %s: checksum mismatch: received=%x computed=%x",
838 : from_str, ifp->name, recv_checksum, checksum);
839 0 : return -1;
840 : }
841 :
842 0 : mtracep->checksum = checksum;
843 :
844 : /* Collecting IGMP Rx stats */
845 0 : igmp->igmp_stats.mtrace_rsp++;
846 :
847 0 : if (PIM_DEBUG_MTRACE)
848 0 : mtrace_debug(pim_ifp, mtracep, igmp_msg_len);
849 :
850 : /* Drop duplicate packets */
851 0 : if (qry_id == mtracep->qry_id && rsp_dst == ip_hdr->ip_dst.s_addr) {
852 0 : if (PIM_DEBUG_MTRACE)
853 0 : zlog_debug("duplicate mtrace response packet dropped");
854 0 : return -1;
855 : }
856 :
857 0 : qry_id = mtracep->qry_id;
858 0 : rsp_dst = ip_hdr->ip_dst.s_addr;
859 :
860 0 : return mtrace_forward_packet(pim, ip_hdr);
861 : }
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