2 * Multicast traceroute for FRRouting
3 * Copyright (C) 2017 Mladen Sablic
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.
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.
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
20 /* based on draft-ietf-idmr-traceroute-ipm-07 */
29 #include "pim_ifchannel.h"
30 #include "pim_macro.h"
31 #include "pim_igmp_mtrace.h"
33 static struct in_addr
mtrace_primary_address(struct interface
*ifp
)
35 struct connected
*ifc
;
36 struct listnode
*node
;
38 struct pim_interface
*pim_ifp
;
42 return pim_ifp
->primary_address
;
45 any
.s_addr
= INADDR_ANY
;
47 for (ALL_LIST_ELEMENTS_RO(ifp
->connected
, node
, ifc
)) {
48 struct prefix
*p
= ifc
->address
;
50 if (p
->family
!= AF_INET
)
53 if (!CHECK_FLAG(ifc
->flags
, ZEBRA_IFA_SECONDARY
))
55 /* in case no primary found, return a secondary */
61 static bool mtrace_fwd_info_weak(struct pim_instance
*pim
,
62 struct igmp_mtrace
*mtracep
,
63 struct igmp_mtrace_rsp
*rspp
,
64 struct interface
**ifpp
)
66 struct pim_nexthop nexthop
;
67 struct interface
*ifp_in
;
68 struct in_addr nh_addr
;
70 char nexthop_str
[INET_ADDRSTRLEN
];
74 memset(&nexthop
, 0, sizeof(nexthop
));
76 ret
= pim_nexthop_lookup(pim
, &nexthop
, mtracep
->src_addr
, 1);
80 zlog_debug("mtrace not found neighbor");
85 zlog_debug("mtrace pim_nexthop_lookup OK");
88 zlog_warn("mtrace next_hop=%s",
89 inet_ntop(nexthop
.mrib_nexthop_addr
.family
,
90 &nexthop
.mrib_nexthop_addr
.u
.prefix
,
91 nexthop_str
, sizeof(nexthop_str
)));
93 if (nexthop
.mrib_nexthop_addr
.family
== AF_INET
)
94 nh_addr
= nexthop
.mrib_nexthop_addr
.u
.prefix4
;
96 ifp_in
= nexthop
.interface
;
98 /* return interface for forwarding mtrace packets */
101 /* 6.2.2. 4. Fill in the Incoming Interface Address... */
102 rspp
->incoming
= mtrace_primary_address(ifp_in
);
103 rspp
->prev_hop
= nh_addr
;
104 rspp
->in_count
= htonl(MTRACE_UNKNOWN_COUNT
);
105 rspp
->total
= htonl(MTRACE_UNKNOWN_COUNT
);
106 rspp
->rtg_proto
= MTRACE_RTG_PROTO_PIM
;
110 static bool mtrace_fwd_info(struct pim_instance
*pim
,
111 struct igmp_mtrace
*mtracep
,
112 struct igmp_mtrace_rsp
*rspp
,
113 struct interface
**ifpp
)
116 struct pim_upstream
*up
;
117 struct interface
*ifp_in
;
118 struct in_addr nh_addr
;
120 char up_str
[INET_ADDRSTRLEN
];
122 memset(&sg
, 0, sizeof(struct prefix_sg
));
123 sg
.src
= mtracep
->src_addr
;
124 sg
.grp
= mtracep
->grp_addr
;
126 up
= pim_upstream_find(pim
, &sg
);
130 up
= pim_upstream_find(pim
, &sg
);
136 ifp_in
= up
->rpf
.source_nexthop
.interface
;
137 nh_addr
= up
->rpf
.source_nexthop
.mrib_nexthop_addr
.u
.prefix4
;
138 total
= htonl(MTRACE_UNKNOWN_COUNT
);
140 if (PIM_DEBUG_MTRACE
)
141 zlog_debug("fwd_info: upstream next hop=%s",
142 inet_ntop(AF_INET
, &(nh_addr
), up_str
,
146 total
= up
->channel_oil
->cc
.pktcnt
;
148 /* return interface for forwarding mtrace packets */
151 /* 6.2.2. 4. Fill in the Incoming Interface Address... */
152 rspp
->incoming
= mtrace_primary_address(ifp_in
);
153 rspp
->prev_hop
= nh_addr
;
154 rspp
->in_count
= htonl(MTRACE_UNKNOWN_COUNT
);
156 rspp
->rtg_proto
= MTRACE_RTG_PROTO_PIM
;
158 /* 6.2.2. 4. Fill in ... S, and Src Mask */
161 rspp
->src_mask
= MTRACE_SRC_MASK_SOURCE
;
164 rspp
->src_mask
= MTRACE_SRC_MASK_GROUP
;
170 static void mtrace_rsp_set_fwd_code(struct igmp_mtrace_rsp
*mtrace_rspp
,
171 enum mtrace_fwd_code fwd_code
)
173 if (mtrace_rspp
->fwd_code
== MTRACE_FWD_CODE_NO_ERROR
)
174 mtrace_rspp
->fwd_code
= fwd_code
;
177 static void mtrace_rsp_init(struct igmp_mtrace_rsp
*mtrace_rspp
)
179 mtrace_rspp
->arrival
= 0;
180 mtrace_rspp
->incoming
.s_addr
= 0;
181 mtrace_rspp
->outgoing
.s_addr
= 0;
182 mtrace_rspp
->prev_hop
.s_addr
= 0;
183 mtrace_rspp
->in_count
= htonl(MTRACE_UNKNOWN_COUNT
);
184 mtrace_rspp
->out_count
= htonl(MTRACE_UNKNOWN_COUNT
);
185 mtrace_rspp
->total
= htonl(MTRACE_UNKNOWN_COUNT
);
186 mtrace_rspp
->rtg_proto
= 0;
187 mtrace_rspp
->fwd_ttl
= 0;
188 mtrace_rspp
->mbz
= 0;
190 mtrace_rspp
->src_mask
= 0;
191 mtrace_rspp
->fwd_code
= MTRACE_FWD_CODE_NO_ERROR
;
194 static void mtrace_rsp_debug(uint32_t qry_id
, int rsp
,
195 struct igmp_mtrace_rsp
*mrspp
)
197 char inc_str
[INET_ADDRSTRLEN
];
198 char out_str
[INET_ADDRSTRLEN
];
199 char prv_str
[INET_ADDRSTRLEN
];
202 "Rx mt(%d) qid=%ud arr=%x in=%s out=%s prev=%s proto=%d fwd=%d",
203 rsp
, ntohl(qry_id
), mrspp
->arrival
,
204 inet_ntop(AF_INET
, &(mrspp
->incoming
), inc_str
,
206 inet_ntop(AF_INET
, &(mrspp
->outgoing
), out_str
,
208 inet_ntop(AF_INET
, &(mrspp
->prev_hop
), prv_str
,
210 mrspp
->rtg_proto
, mrspp
->fwd_code
);
213 static void mtrace_debug(struct pim_interface
*pim_ifp
,
214 struct igmp_mtrace
*mtracep
, int mtrace_len
)
216 char inc_str
[INET_ADDRSTRLEN
];
217 char grp_str
[INET_ADDRSTRLEN
];
218 char src_str
[INET_ADDRSTRLEN
];
219 char dst_str
[INET_ADDRSTRLEN
];
220 char rsp_str
[INET_ADDRSTRLEN
];
222 struct in_addr ga
, sa
, da
, ra
;
224 ga
= mtracep
->grp_addr
;
225 sa
= mtracep
->src_addr
;
226 da
= mtracep
->dst_addr
;
227 ra
= mtracep
->rsp_addr
;
230 "Rx mtrace packet incoming on %s: "
231 "hops=%d type=%d size=%d, grp=%s, src=%s,"
232 " dst=%s rsp=%s ttl=%d qid=%ud",
233 inet_ntop(AF_INET
, &(pim_ifp
->primary_address
), inc_str
,
235 mtracep
->hops
, mtracep
->type
, mtrace_len
,
236 inet_ntop(AF_INET
, &ga
, grp_str
,
238 inet_ntop(AF_INET
, &sa
, src_str
,
240 inet_ntop(AF_INET
, &da
, dst_str
,
242 inet_ntop(AF_INET
, &ra
, rsp_str
,
244 mtracep
->rsp_ttl
, ntohl(mtracep
->qry_id
));
245 if (mtrace_len
> (int)sizeof(struct igmp_mtrace
)) {
249 int responses
= mtrace_len
- sizeof(struct igmp_mtrace
);
251 if ((responses
% sizeof(struct igmp_mtrace_rsp
)) != 0)
252 if (PIM_DEBUG_MTRACE
)
254 "Mtrace response block of wrong"
257 responses
= responses
/ sizeof(struct igmp_mtrace_rsp
);
259 for (i
= 0; i
< responses
; i
++)
260 mtrace_rsp_debug(mtracep
->qry_id
, i
, &mtracep
->rsp
[i
]);
264 /* 5.1 Query Arrival Time */
265 static uint32_t query_arrival_time(void)
270 char m_qat
[] = "Query arrival time lookup failed: errno=%d: %s";
272 if (gettimeofday(&tv
, NULL
) < 0) {
273 if (PIM_DEBUG_MTRACE
)
274 zlog_warn(m_qat
, errno
, safe_strerror(errno
));
277 /* not sure second offset correct, as I get different value */
278 qat
= ((tv
.tv_sec
+ 32384) << 16) + ((tv
.tv_usec
<< 10) / 15625);
283 static int mtrace_send_packet(struct interface
*ifp
,
284 struct igmp_mtrace
*mtracep
,
285 size_t mtrace_buf_len
, struct in_addr dst_addr
,
286 struct in_addr group_addr
)
288 struct sockaddr_in to
;
293 char if_str
[INET_ADDRSTRLEN
];
294 char rsp_str
[INET_ADDRSTRLEN
];
297 memset(&to
, 0, sizeof(to
));
298 to
.sin_family
= AF_INET
;
299 to
.sin_addr
= dst_addr
;
302 if (PIM_DEBUG_MTRACE
) {
303 struct in_addr if_addr
;
305 if_addr
= mtrace_primary_address(ifp
);
307 "Sending mtrace packet to %s on %s",
308 inet_ntop(AF_INET
, &mtracep
->rsp_addr
, rsp_str
,
310 inet_ntop(AF_INET
, &if_addr
, if_str
, sizeof(if_str
)));
313 fd
= pim_socket_raw(IPPROTO_IGMP
);
318 ret
= pim_socket_bind(fd
, ifp
);
325 if (IPV4_CLASS_DE(ntohl(dst_addr
.s_addr
))) {
326 if (IPV4_MC_LINKLOCAL(ntohl(dst_addr
.s_addr
))) {
329 if (mtracep
->type
== PIM_IGMP_MTRACE_RESPONSE
)
330 ttl
= mtracep
->rsp_ttl
;
334 ret
= setsockopt(fd
, IPPROTO_IP
, IP_MULTICAST_TTL
, &ttl
,
338 if (PIM_DEBUG_MTRACE
)
339 zlog_warn("Failed to set socket multicast TTL");
345 sent
= sendto(fd
, (char *)mtracep
, mtrace_buf_len
, MSG_DONTWAIT
,
346 (struct sockaddr
*)&to
, tolen
);
348 if (sent
!= (ssize_t
)mtrace_buf_len
) {
349 char dst_str
[INET_ADDRSTRLEN
];
350 char group_str
[INET_ADDRSTRLEN
];
352 pim_inet4_dump("<dst?>", dst_addr
, dst_str
, sizeof(dst_str
));
353 pim_inet4_dump("<group?>", group_addr
, group_str
,
356 if (PIM_DEBUG_MTRACE
)
358 "Send mtrace request failed for %s on"
359 "%s: group=%s msg_size=%zd: errno=%d: "
361 dst_str
, ifp
->name
, group_str
,
362 mtrace_buf_len
, errno
,
363 safe_strerror(errno
));
365 if (PIM_DEBUG_MTRACE
)
367 "Send mtrace request failed for %s on"
368 " %s: group=%s msg_size=%zd: sent=%zd",
369 dst_str
, ifp
->name
, group_str
,
370 mtrace_buf_len
, sent
);
381 static int mtrace_un_forward_packet(struct pim_instance
*pim
, struct ip
*ip_hdr
,
382 struct interface
*interface
)
384 struct pim_nexthop nexthop
;
385 struct sockaddr_in to
;
386 struct interface
*if_out
;
393 checksum
= ip_hdr
->ip_sum
;
397 if (checksum
!= in_cksum(ip_hdr
, ip_hdr
->ip_hl
* 4))
400 if (ip_hdr
->ip_ttl
-- <= 1)
403 ip_hdr
->ip_sum
= in_cksum(ip_hdr
, ip_hdr
->ip_hl
* 4);
405 fd
= pim_socket_raw(IPPROTO_RAW
);
410 pim_socket_ip_hdr(fd
);
412 if (interface
== NULL
) {
413 memset(&nexthop
, 0, sizeof(nexthop
));
414 ret
= pim_nexthop_lookup(pim
, &nexthop
, ip_hdr
->ip_dst
, 0);
418 if (PIM_DEBUG_MTRACE
)
420 "Dropping mtrace packet, "
421 "no route to destination");
425 if_out
= nexthop
.interface
;
430 ret
= pim_socket_bind(fd
, if_out
);
437 memset(&to
, 0, sizeof(to
));
438 to
.sin_family
= AF_INET
;
439 to
.sin_addr
= ip_hdr
->ip_dst
;
442 sent
= sendto(fd
, ip_hdr
, ntohs(ip_hdr
->ip_len
), 0,
443 (struct sockaddr
*)&to
, tolen
);
448 if (PIM_DEBUG_MTRACE
)
450 "Failed to forward mtrace packet:"
451 " sendto errno=%d, %s",
452 errno
, safe_strerror(errno
));
456 if (PIM_DEBUG_MTRACE
) {
457 zlog_debug("Fwd mtrace packet len=%u to %s ttl=%u",
458 ntohs(ip_hdr
->ip_len
), inet_ntoa(ip_hdr
->ip_dst
),
465 static int mtrace_mc_forward_packet(struct pim_instance
*pim
, struct ip
*ip_hdr
)
468 struct channel_oil
*c_oil
;
469 struct listnode
*chnode
;
470 struct listnode
*chnextnode
;
471 struct pim_ifchannel
*ch
= NULL
;
474 memset(&sg
, 0, sizeof(struct prefix_sg
));
475 sg
.grp
= ip_hdr
->ip_dst
;
477 c_oil
= pim_find_channel_oil(pim
, &sg
);
480 if (PIM_DEBUG_MTRACE
) {
482 "Dropping mtrace multicast packet "
483 "len=%u to %s ttl=%u",
484 ntohs(ip_hdr
->ip_len
),
485 inet_ntoa(ip_hdr
->ip_dst
), ip_hdr
->ip_ttl
);
489 if (c_oil
->up
== NULL
)
491 if (c_oil
->up
->ifchannels
== NULL
)
493 for (ALL_LIST_ELEMENTS(c_oil
->up
->ifchannels
, chnode
, chnextnode
, ch
)) {
494 if (pim_macro_chisin_oiflist(ch
)) {
497 r
= mtrace_un_forward_packet(pim
, ip_hdr
,
507 static int mtrace_forward_packet(struct pim_instance
*pim
, struct ip
*ip_hdr
)
509 if (IPV4_CLASS_DE(ntohl(ip_hdr
->ip_dst
.s_addr
)))
510 return mtrace_mc_forward_packet(pim
, ip_hdr
);
512 return mtrace_un_forward_packet(pim
, ip_hdr
, NULL
);
515 static int mtrace_send_mc_response(struct pim_instance
*pim
,
516 struct igmp_mtrace
*mtracep
,
520 struct channel_oil
*c_oil
;
521 struct listnode
*chnode
;
522 struct listnode
*chnextnode
;
523 struct pim_ifchannel
*ch
= NULL
;
526 memset(&sg
, 0, sizeof(struct prefix_sg
));
527 sg
.grp
= mtracep
->rsp_addr
;
529 c_oil
= pim_find_channel_oil(pim
, &sg
);
532 if (PIM_DEBUG_MTRACE
) {
534 "Dropping mtrace multicast response packet "
536 (unsigned int)mtrace_len
,
537 inet_ntoa(mtracep
->rsp_addr
));
541 if (c_oil
->up
== NULL
)
543 if (c_oil
->up
->ifchannels
== NULL
)
545 for (ALL_LIST_ELEMENTS(c_oil
->up
->ifchannels
, chnode
, chnextnode
, ch
)) {
546 if (pim_macro_chisin_oiflist(ch
)) {
549 r
= mtrace_send_packet(ch
->interface
, mtracep
,
550 mtrace_len
, mtracep
->rsp_addr
,
559 /* 6.5 Sending Traceroute Responses */
560 static int mtrace_send_response(struct pim_instance
*pim
,
561 struct igmp_mtrace
*mtracep
, size_t mtrace_len
)
563 struct pim_nexthop nexthop
;
566 mtracep
->type
= PIM_IGMP_MTRACE_RESPONSE
;
568 mtracep
->checksum
= 0;
569 mtracep
->checksum
= in_cksum((char *)mtracep
, mtrace_len
);
571 if (IPV4_CLASS_DE(ntohl(mtracep
->rsp_addr
.s_addr
))) {
572 struct pim_rpf
*p_rpf
;
573 char grp_str
[INET_ADDRSTRLEN
];
575 if (pim_rp_i_am_rp(pim
, mtracep
->rsp_addr
))
576 return mtrace_send_mc_response(pim
, mtracep
,
579 p_rpf
= pim_rp_g(pim
, mtracep
->rsp_addr
);
582 if (PIM_DEBUG_MTRACE
)
583 zlog_warn("mtrace no RP for %s",
585 &(mtracep
->rsp_addr
),
586 grp_str
, sizeof(grp_str
)));
589 nexthop
= p_rpf
->source_nexthop
;
590 if (PIM_DEBUG_MTRACE
)
591 zlog_debug("mtrace response to RP");
593 memset(&nexthop
, 0, sizeof(nexthop
));
594 /* TODO: should use unicast rib lookup */
595 ret
= pim_nexthop_lookup(pim
, &nexthop
, mtracep
->rsp_addr
, 1);
598 if (PIM_DEBUG_MTRACE
)
600 "Dropped response qid=%ud, no route to "
607 return mtrace_send_packet(nexthop
.interface
, mtracep
, mtrace_len
,
608 mtracep
->rsp_addr
, mtracep
->grp_addr
);
611 int igmp_mtrace_recv_qry_req(struct igmp_sock
*igmp
, struct ip
*ip_hdr
,
612 struct in_addr from
, const char *from_str
,
613 char *igmp_msg
, int igmp_msg_len
)
615 static uint32_t qry_id
, qry_src
;
616 char mtrace_buf
[MTRACE_HDR_SIZE
+ MTRACE_MAX_HOPS
* MTRACE_RSP_SIZE
];
617 struct interface
*ifp
;
618 struct interface
*out_ifp
= NULL
;
619 struct pim_interface
*pim_ifp
;
620 struct pim_instance
*pim
;
621 struct igmp_mtrace
*mtracep
;
622 struct igmp_mtrace_rsp
*rspp
;
623 struct in_addr nh_addr
;
624 enum mtrace_fwd_code fwd_code
= MTRACE_FWD_CODE_NO_ERROR
;
626 int last_rsp_ind
= 0;
628 uint16_t recv_checksum
;
633 ifp
= igmp
->interface
;
638 * 6. Router Behaviour
639 * Check if mtrace packet is addressed elsewhere and forward,
642 if (!IPV4_CLASS_DE(ntohl(ip_hdr
->ip_dst
.s_addr
)))
643 if (!if_lookup_exact_address(&ip_hdr
->ip_dst
, AF_INET
,
645 return mtrace_forward_packet(pim
, ip_hdr
);
647 if (igmp_msg_len
< (int)sizeof(struct igmp_mtrace
)) {
648 if (PIM_DEBUG_MTRACE
)
650 "Recv mtrace packet from %s on %s: too short,"
652 from_str
, ifp
->name
, igmp_msg_len
,
653 sizeof(struct igmp_mtrace
));
657 mtracep
= (struct igmp_mtrace
*)igmp_msg
;
659 recv_checksum
= mtracep
->checksum
;
661 mtracep
->checksum
= 0;
663 checksum
= in_cksum(igmp_msg
, igmp_msg_len
);
665 if (recv_checksum
!= checksum
) {
666 if (PIM_DEBUG_MTRACE
)
668 "Recv mtrace packet from %s on %s: checksum"
669 " mismatch: received=%x computed=%x",
670 from_str
, ifp
->name
, recv_checksum
, checksum
);
674 /* Collecting IGMP Rx stats */
675 igmp
->rx_stats
.mtrace_req
++;
677 if (PIM_DEBUG_MTRACE
)
678 mtrace_debug(pim_ifp
, mtracep
, igmp_msg_len
);
680 /* subtract header from message length */
681 r_len
= igmp_msg_len
- sizeof(struct igmp_mtrace
);
683 /* Classify mtrace packet, check if it is a query */
685 if (PIM_DEBUG_MTRACE
)
686 zlog_debug("Received IGMP multicast traceroute query");
688 /* 6.1.1 Packet verification */
689 if (!pim_if_connected_to_source(ifp
, mtracep
->dst_addr
)) {
690 if (IPV4_CLASS_DE(ntohl(ip_hdr
->ip_dst
.s_addr
))) {
691 if (PIM_DEBUG_MTRACE
)
693 "Dropping multicast query "
694 "on wrong interface");
697 /* Unicast query on wrong interface */
698 fwd_code
= MTRACE_FWD_CODE_WRONG_IF
;
699 if (PIM_DEBUG_MTRACE
)
700 zlog_debug("Multicast query on wrong interface");
702 if (qry_id
== mtracep
->qry_id
&& qry_src
== from
.s_addr
) {
703 if (PIM_DEBUG_MTRACE
)
705 "Dropping multicast query with "
706 "duplicate source and id");
709 qry_id
= mtracep
->qry_id
;
710 qry_src
= from
.s_addr
;
712 /* if response fields length is equal to a whole number of responses */
713 else if ((r_len
% sizeof(struct igmp_mtrace_rsp
)) == 0) {
714 r_len
= igmp_msg_len
- sizeof(struct igmp_mtrace
);
717 last_rsp_ind
= r_len
/ sizeof(struct igmp_mtrace_rsp
);
718 if (last_rsp_ind
> MTRACE_MAX_HOPS
) {
719 if (PIM_DEBUG_MTRACE
)
720 zlog_warn("Mtrace request of excessive size");
724 if (PIM_DEBUG_MTRACE
)
726 "Recv mtrace packet from %s on %s: "
728 from_str
, ifp
->name
, igmp_msg_len
);
732 /* 6.2.1 Packet Verification - drop not link-local multicast */
733 if (IPV4_CLASS_DE(ntohl(ip_hdr
->ip_dst
.s_addr
))
734 && !IPV4_MC_LINKLOCAL(ntohl(ip_hdr
->ip_dst
.s_addr
))) {
735 if (PIM_DEBUG_MTRACE
)
737 "Recv mtrace packet from %s on %s:"
738 " not link-local multicast %s",
739 from_str
, ifp
->name
, inet_ntoa(ip_hdr
->ip_dst
));
743 /* 6.2.2. Normal Processing */
745 /* 6.2.2. 1. If there is room in the current buffer? */
747 if (last_rsp_ind
== MTRACE_MAX_HOPS
) {
748 /* ...there was no room... */
749 mtracep
->rsp
[MTRACE_MAX_HOPS
- 1].fwd_code
=
750 MTRACE_FWD_CODE_NO_SPACE
;
751 return mtrace_send_response(pim_ifp
->pim
, mtracep
,
755 /* ...insert new response block... */
757 /* calculate new mtrace lenght with extra response */
758 mtrace_len
= igmp_msg_len
+ sizeof(struct igmp_mtrace_rsp
);
760 /* copy received query/request */
761 memcpy(mtrace_buf
, igmp_msg
, igmp_msg_len
);
763 /* repoint mtracep pointer to copy */
764 mtracep
= (struct igmp_mtrace
*)mtrace_buf
;
766 /* pointer for extra response field to be filled in */
767 rspp
= &mtracep
->rsp
[last_rsp_ind
];
769 /* initialize extra response field */
770 mtrace_rsp_init(rspp
);
772 /* carry over any error noted when receiving the query */
773 rspp
->fwd_code
= fwd_code
;
775 /* ...and fill in Query Arrival Time... */
776 rspp
->arrival
= htonl(query_arrival_time());
777 rspp
->outgoing
= pim_ifp
->primary_address
;
778 rspp
->out_count
= htonl(MTRACE_UNKNOWN_COUNT
);
781 /* 6.2.2. 2. Attempt to determine the forwarding information... */
783 if (mtracep
->grp_addr
.s_addr
)
784 fwd_info
= mtrace_fwd_info(pim
, mtracep
, rspp
, &out_ifp
);
786 fwd_info
= mtrace_fwd_info_weak(pim
, mtracep
, rspp
, &out_ifp
);
788 /* 6.2.2 3. If no forwarding information... */
790 if (PIM_DEBUG_MTRACE
)
791 zlog_debug("mtrace not found multicast state");
792 mtrace_rsp_set_fwd_code(rspp
, MTRACE_FWD_CODE_NO_ROUTE
);
793 /* 6.2.2. 3. forward the packet to requester */
794 return mtrace_send_response(pim
, mtracep
, mtrace_len
);
797 nh_addr
= rspp
->prev_hop
;
799 reached_source
= false;
801 if (nh_addr
.s_addr
== 0) {
802 /* no pim? i.e. 7.5.3. No Previous Hop */
803 if (!out_ifp
->info
) {
804 if (PIM_DEBUG_MTRACE
)
805 zlog_debug("mtrace not found incoming if w/ pim");
806 mtrace_rsp_set_fwd_code(rspp
,
807 MTRACE_FWD_CODE_NO_MULTICAST
);
808 return mtrace_send_response(pim
, mtracep
, mtrace_len
);
810 /* reached source? i.e. 7.5.1 Arriving at source */
811 if (pim_if_connected_to_source(out_ifp
, mtracep
->src_addr
)) {
812 reached_source
= true;
813 rspp
->prev_hop
= mtracep
->src_addr
;
816 * 6.4 Forwarding Traceroute Requests:
817 * Previous-hop router not known,
818 * packet is sent to an appropriate multicast address
820 (void)inet_aton(MCAST_ALL_ROUTERS
, &nh_addr
);
823 /* 6.2.2 8. If this router is the Rendez-vous Point */
824 if (pim_rp_i_am_rp(pim
, mtracep
->grp_addr
)) {
825 mtrace_rsp_set_fwd_code(rspp
, MTRACE_FWD_CODE_REACHED_RP
);
826 /* 7.7.1. PIM-SM ...RP has not performed source-specific join */
827 if (rspp
->src_mask
== MTRACE_SRC_MASK_GROUP
)
828 return mtrace_send_response(pim
, mtracep
, mtrace_len
);
832 * 6.4 Forwarding Traceroute Requests: the number of response
833 * blocks exceeds number of responses, so forward to the requester.
835 if (mtracep
->hops
<= (last_rsp_ind
+ 1))
836 return mtrace_send_response(pim
, mtracep
, mtrace_len
);
838 /* 7.5.1. Arriving at source: terminate trace */
840 return mtrace_send_response(pim
, mtracep
, mtrace_len
);
842 mtracep
->checksum
= 0;
844 mtracep
->checksum
= in_cksum(mtrace_buf
, mtrace_len
);
846 /* 6.4 Forwarding Traceroute Requests: response blocks less than req. */
847 return mtrace_send_packet(out_ifp
, mtracep
, mtrace_len
, nh_addr
,
851 /* 6.3. Traceroute responses */
852 int igmp_mtrace_recv_response(struct igmp_sock
*igmp
, struct ip
*ip_hdr
,
853 struct in_addr from
, const char *from_str
,
854 char *igmp_msg
, int igmp_msg_len
)
856 static uint32_t qry_id
, rsp_dst
;
857 struct interface
*ifp
;
858 struct pim_interface
*pim_ifp
;
859 struct pim_instance
*pim
;
860 struct igmp_mtrace
*mtracep
;
861 uint16_t recv_checksum
;
864 ifp
= igmp
->interface
;
868 mtracep
= (struct igmp_mtrace
*)igmp_msg
;
870 recv_checksum
= mtracep
->checksum
;
872 mtracep
->checksum
= 0;
874 checksum
= in_cksum(igmp_msg
, igmp_msg_len
);
876 if (recv_checksum
!= checksum
) {
877 if (PIM_DEBUG_MTRACE
)
879 "Recv mtrace response from %s on %s: checksum"
880 " mismatch: received=%x computed=%x",
881 from_str
, ifp
->name
, recv_checksum
, checksum
);
885 mtracep
->checksum
= checksum
;
887 /* Collecting IGMP Rx stats */
888 igmp
->rx_stats
.mtrace_rsp
++;
890 if (PIM_DEBUG_MTRACE
)
891 mtrace_debug(pim_ifp
, mtracep
, igmp_msg_len
);
893 /* Drop duplicate packets */
894 if (qry_id
== mtracep
->qry_id
&& rsp_dst
== ip_hdr
->ip_dst
.s_addr
) {
895 if (PIM_DEBUG_MTRACE
)
896 zlog_debug("duplicate mtrace response packet dropped");
900 qry_id
= mtracep
->qry_id
;
901 rsp_dst
= ip_hdr
->ip_dst
.s_addr
;
903 return mtrace_forward_packet(pim
, ip_hdr
);