forked from FRRouting/frr
-
Notifications
You must be signed in to change notification settings - Fork 3
/
Copy pathbfd_packet.c
1237 lines (1040 loc) · 30.8 KB
/
bfd_packet.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*********************************************************************
* Copyright 2017 Cumulus Networks, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* bfd_packet.c: implements the BFD protocol packet handling.
*
* Authors
* -------
* Shrijeet Mukherjee [shm@cumulusnetworks.com]
* Kanna Rajagopal [kanna@cumulusnetworks.com]
* Radhika Mahankali [Radhika@cumulusnetworks.com]
*/
#include <zebra.h>
#ifdef BFD_LINUX
#include <linux/if_packet.h>
#endif /* BFD_LINUX */
#include <netinet/if_ether.h>
#include <netinet/udp.h>
#include "lib/sockopt.h"
#include "bfd.h"
/*
* Prototypes
*/
static int ptm_bfd_process_echo_pkt(struct bfd_vrf_global *bvrf, int s);
int _ptm_bfd_send(struct bfd_session *bs, uint16_t *port, const void *data,
size_t datalen);
static void bfd_sd_reschedule(struct bfd_vrf_global *bvrf, int sd);
ssize_t bfd_recv_ipv4(int sd, uint8_t *msgbuf, size_t msgbuflen, uint8_t *ttl,
ifindex_t *ifindex, struct sockaddr_any *local,
struct sockaddr_any *peer);
ssize_t bfd_recv_ipv6(int sd, uint8_t *msgbuf, size_t msgbuflen, uint8_t *ttl,
ifindex_t *ifindex, struct sockaddr_any *local,
struct sockaddr_any *peer);
int bp_udp_send(int sd, uint8_t ttl, uint8_t *data, size_t datalen,
struct sockaddr *to, socklen_t tolen);
int bp_bfd_echo_in(struct bfd_vrf_global *bvrf, int sd,
uint8_t *ttl, uint32_t *my_discr);
/* socket related prototypes */
static void bp_set_ipopts(int sd);
static void bp_bind_ip(int sd, uint16_t port);
static void bp_set_ipv6opts(int sd);
static void bp_bind_ipv6(int sd, uint16_t port);
/*
* Functions
*/
int _ptm_bfd_send(struct bfd_session *bs, uint16_t *port, const void *data,
size_t datalen)
{
struct sockaddr *sa;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
socklen_t slen;
ssize_t rv;
int sd = -1;
if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_IPV6)) {
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
memcpy(&sin6.sin6_addr, &bs->key.peer, sizeof(sin6.sin6_addr));
if (bs->ifp && IN6_IS_ADDR_LINKLOCAL(&sin6.sin6_addr))
sin6.sin6_scope_id = bs->ifp->ifindex;
sin6.sin6_port =
(port) ? *port
: (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH))
? htons(BFD_DEF_MHOP_DEST_PORT)
: htons(BFD_DEFDESTPORT);
sd = bs->sock;
sa = (struct sockaddr *)&sin6;
slen = sizeof(sin6);
} else {
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
memcpy(&sin.sin_addr, &bs->key.peer, sizeof(sin.sin_addr));
sin.sin_port =
(port) ? *port
: (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH))
? htons(BFD_DEF_MHOP_DEST_PORT)
: htons(BFD_DEFDESTPORT);
sd = bs->sock;
sa = (struct sockaddr *)&sin;
slen = sizeof(sin);
}
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
sa->sa_len = slen;
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
rv = sendto(sd, data, datalen, 0, sa, slen);
if (rv <= 0) {
if (bglobal.debug_network)
zlog_debug("packet-send: send failure: %s",
strerror(errno));
return -1;
}
if (rv < (ssize_t)datalen) {
if (bglobal.debug_network)
zlog_debug("packet-send: send partial: %s",
strerror(errno));
}
return 0;
}
void ptm_bfd_echo_snd(struct bfd_session *bfd)
{
struct sockaddr *sa;
socklen_t salen;
int sd;
struct bfd_echo_pkt bep;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
struct bfd_vrf_global *bvrf = bfd_vrf_look_by_session(bfd);
if (!bvrf)
return;
if (!CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE))
SET_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE);
memset(&bep, 0, sizeof(bep));
bep.ver = BFD_ECHO_VERSION;
bep.len = BFD_ECHO_PKT_LEN;
bep.my_discr = htonl(bfd->discrs.my_discr);
if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_IPV6)) {
if (bvrf->bg_echov6 == -1)
return;
sd = bvrf->bg_echov6;
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
memcpy(&sin6.sin6_addr, &bfd->key.peer, sizeof(sin6.sin6_addr));
if (bfd->ifp && IN6_IS_ADDR_LINKLOCAL(&sin6.sin6_addr))
sin6.sin6_scope_id = bfd->ifp->ifindex;
sin6.sin6_port = htons(BFD_DEF_ECHO_PORT);
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
sin6.sin6_len = sizeof(sin6);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
sa = (struct sockaddr *)&sin6;
salen = sizeof(sin6);
} else {
sd = bvrf->bg_echo;
memset(&sin6, 0, sizeof(sin6));
sin.sin_family = AF_INET;
memcpy(&sin.sin_addr, &bfd->key.peer, sizeof(sin.sin_addr));
sin.sin_port = htons(BFD_DEF_ECHO_PORT);
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
sin.sin_len = sizeof(sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
sa = (struct sockaddr *)&sin;
salen = sizeof(sin);
}
if (bp_udp_send(sd, BFD_TTL_VAL, (uint8_t *)&bep, sizeof(bep), sa,
salen)
== -1)
return;
bfd->stats.tx_echo_pkt++;
}
static int ptm_bfd_process_echo_pkt(struct bfd_vrf_global *bvrf, int s)
{
struct bfd_session *bfd;
uint32_t my_discr = 0;
uint8_t ttl = 0;
/* Receive and parse echo packet. */
if (bp_bfd_echo_in(bvrf, s, &ttl, &my_discr) == -1)
return 0;
/* Your discriminator not zero - use it to find session */
bfd = bfd_id_lookup(my_discr);
if (bfd == NULL) {
if (bglobal.debug_network)
zlog_debug("echo-packet: no matching session (id:%u)",
my_discr);
return -1;
}
if (!CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE)) {
if (bglobal.debug_network)
zlog_debug("echo-packet: echo disabled [%s] (id:%u)",
bs_to_string(bfd), my_discr);
return -1;
}
bfd->stats.rx_echo_pkt++;
/* Compute detect time */
bfd->echo_detect_TO = bfd->remote_detect_mult * bfd->echo_xmt_TO;
/* Update echo receive timeout. */
if (bfd->echo_detect_TO > 0)
bfd_echo_recvtimer_update(bfd);
return 0;
}
void ptm_bfd_snd(struct bfd_session *bfd, int fbit)
{
struct bfd_pkt cp = {};
/* Set fields according to section 6.5.7 */
cp.diag = bfd->local_diag;
BFD_SETVER(cp.diag, BFD_VERSION);
cp.flags = 0;
BFD_SETSTATE(cp.flags, bfd->ses_state);
if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_CBIT))
BFD_SETCBIT(cp.flags, BFD_CBIT);
BFD_SETDEMANDBIT(cp.flags, BFD_DEF_DEMAND);
/*
* Polling and Final can't be set at the same time.
*
* RFC 5880, Section 6.5.
*/
BFD_SETFBIT(cp.flags, fbit);
if (fbit == 0)
BFD_SETPBIT(cp.flags, bfd->polling);
cp.detect_mult = bfd->detect_mult;
cp.len = BFD_PKT_LEN;
cp.discrs.my_discr = htonl(bfd->discrs.my_discr);
cp.discrs.remote_discr = htonl(bfd->discrs.remote_discr);
if (bfd->polling) {
cp.timers.desired_min_tx =
htonl(bfd->timers.desired_min_tx);
cp.timers.required_min_rx =
htonl(bfd->timers.required_min_rx);
} else {
/*
* We can only announce current setting on poll, this
* avoids timing mismatch with our peer and give it
* the oportunity to learn. See `bs_final_handler` for
* more information.
*/
cp.timers.desired_min_tx =
htonl(bfd->cur_timers.desired_min_tx);
cp.timers.required_min_rx =
htonl(bfd->cur_timers.required_min_rx);
}
cp.timers.required_min_echo = htonl(bfd->timers.required_min_echo);
if (_ptm_bfd_send(bfd, NULL, &cp, BFD_PKT_LEN) != 0)
return;
bfd->stats.tx_ctrl_pkt++;
}
ssize_t bfd_recv_ipv4(int sd, uint8_t *msgbuf, size_t msgbuflen, uint8_t *ttl,
ifindex_t *ifindex, struct sockaddr_any *local,
struct sockaddr_any *peer)
{
struct cmsghdr *cm;
ssize_t mlen;
struct sockaddr_in msgaddr;
struct msghdr msghdr;
struct iovec iov[1];
uint8_t cmsgbuf[255];
/* Prepare the recvmsg params. */
iov[0].iov_base = msgbuf;
iov[0].iov_len = msgbuflen;
memset(&msghdr, 0, sizeof(msghdr));
msghdr.msg_name = &msgaddr;
msghdr.msg_namelen = sizeof(msgaddr);
msghdr.msg_iov = iov;
msghdr.msg_iovlen = 1;
msghdr.msg_control = cmsgbuf;
msghdr.msg_controllen = sizeof(cmsgbuf);
mlen = recvmsg(sd, &msghdr, MSG_DONTWAIT);
if (mlen == -1) {
if (errno != EAGAIN)
zlog_err("ipv4-recv: recv failed: %s", strerror(errno));
return -1;
}
/* Get source address */
peer->sa_sin = *((struct sockaddr_in *)(msghdr.msg_name));
/* Get and check TTL */
for (cm = CMSG_FIRSTHDR(&msghdr); cm != NULL;
cm = CMSG_NXTHDR(&msghdr, cm)) {
if (cm->cmsg_level != IPPROTO_IP)
continue;
switch (cm->cmsg_type) {
#ifdef BFD_LINUX
case IP_TTL: {
uint32_t ttlval;
memcpy(&ttlval, CMSG_DATA(cm), sizeof(ttlval));
if (ttlval > 255) {
if (bglobal.debug_network)
zlog_debug("ipv4-recv: invalid TTL: %u",
ttlval);
return -1;
}
*ttl = ttlval;
break;
}
case IP_PKTINFO: {
struct in_pktinfo *pi =
(struct in_pktinfo *)CMSG_DATA(cm);
if (pi == NULL)
break;
local->sa_sin.sin_family = AF_INET;
local->sa_sin.sin_addr = pi->ipi_addr;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
local->sa_sin.sin_len = sizeof(local->sa_sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
*ifindex = pi->ipi_ifindex;
break;
}
#endif /* BFD_LINUX */
#ifdef BFD_BSD
case IP_RECVTTL: {
memcpy(ttl, CMSG_DATA(cm), sizeof(*ttl));
break;
}
case IP_RECVDSTADDR: {
struct in_addr ia;
memcpy(&ia, CMSG_DATA(cm), sizeof(ia));
local->sa_sin.sin_family = AF_INET;
local->sa_sin.sin_addr = ia;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
local->sa_sin.sin_len = sizeof(local->sa_sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
break;
}
#endif /* BFD_BSD */
default:
/*
* On *BSDs we expect to land here when skipping
* the IP_RECVIF header. It will be handled by
* getsockopt_ifindex() below.
*/
/* NOTHING */
break;
}
}
/* OS agnostic way of getting interface name. */
if (*ifindex == IFINDEX_INTERNAL)
*ifindex = getsockopt_ifindex(AF_INET, &msghdr);
return mlen;
}
ssize_t bfd_recv_ipv6(int sd, uint8_t *msgbuf, size_t msgbuflen, uint8_t *ttl,
ifindex_t *ifindex, struct sockaddr_any *local,
struct sockaddr_any *peer)
{
struct cmsghdr *cm;
struct in6_pktinfo *pi6 = NULL;
ssize_t mlen;
uint32_t ttlval;
struct sockaddr_in6 msgaddr6;
struct msghdr msghdr6;
struct iovec iov[1];
uint8_t cmsgbuf6[255];
/* Prepare the recvmsg params. */
iov[0].iov_base = msgbuf;
iov[0].iov_len = msgbuflen;
memset(&msghdr6, 0, sizeof(msghdr6));
msghdr6.msg_name = &msgaddr6;
msghdr6.msg_namelen = sizeof(msgaddr6);
msghdr6.msg_iov = iov;
msghdr6.msg_iovlen = 1;
msghdr6.msg_control = cmsgbuf6;
msghdr6.msg_controllen = sizeof(cmsgbuf6);
mlen = recvmsg(sd, &msghdr6, MSG_DONTWAIT);
if (mlen == -1) {
if (errno != EAGAIN)
zlog_err("ipv6-recv: recv failed: %s", strerror(errno));
return -1;
}
/* Get source address */
peer->sa_sin6 = *((struct sockaddr_in6 *)(msghdr6.msg_name));
/* Get and check TTL */
for (cm = CMSG_FIRSTHDR(&msghdr6); cm != NULL;
cm = CMSG_NXTHDR(&msghdr6, cm)) {
if (cm->cmsg_level != IPPROTO_IPV6)
continue;
if (cm->cmsg_type == IPV6_HOPLIMIT) {
memcpy(&ttlval, CMSG_DATA(cm), sizeof(ttlval));
if (ttlval > 255) {
if (bglobal.debug_network)
zlog_debug("ipv6-recv: invalid TTL: %u",
ttlval);
return -1;
}
*ttl = ttlval;
} else if (cm->cmsg_type == IPV6_PKTINFO) {
pi6 = (struct in6_pktinfo *)CMSG_DATA(cm);
if (pi6) {
local->sa_sin6.sin6_family = AF_INET6;
local->sa_sin6.sin6_addr = pi6->ipi6_addr;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
local->sa_sin6.sin6_len = sizeof(local->sa_sin6);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
*ifindex = pi6->ipi6_ifindex;
/* Set scope ID for link local addresses. */
if (IN6_IS_ADDR_LINKLOCAL(
&peer->sa_sin6.sin6_addr))
peer->sa_sin6.sin6_scope_id = *ifindex;
if (IN6_IS_ADDR_LINKLOCAL(
&local->sa_sin6.sin6_addr))
local->sa_sin6.sin6_scope_id = *ifindex;
}
}
}
return mlen;
}
static void bfd_sd_reschedule(struct bfd_vrf_global *bvrf, int sd)
{
if (sd == bvrf->bg_shop) {
THREAD_OFF(bvrf->bg_ev[0]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_shop,
&bvrf->bg_ev[0]);
} else if (sd == bvrf->bg_mhop) {
THREAD_OFF(bvrf->bg_ev[1]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_mhop,
&bvrf->bg_ev[1]);
} else if (sd == bvrf->bg_shop6) {
THREAD_OFF(bvrf->bg_ev[2]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_shop6,
&bvrf->bg_ev[2]);
} else if (sd == bvrf->bg_mhop6) {
THREAD_OFF(bvrf->bg_ev[3]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_mhop6,
&bvrf->bg_ev[3]);
} else if (sd == bvrf->bg_echo) {
THREAD_OFF(bvrf->bg_ev[4]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_echo,
&bvrf->bg_ev[4]);
} else if (sd == bvrf->bg_echov6) {
THREAD_OFF(bvrf->bg_ev[5]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_echov6,
&bvrf->bg_ev[5]);
}
}
static void cp_debug(bool mhop, struct sockaddr_any *peer,
struct sockaddr_any *local, ifindex_t ifindex,
vrf_id_t vrfid, const char *fmt, ...)
{
char buf[512], peerstr[128], localstr[128], portstr[64], vrfstr[64];
va_list vl;
/* Don't to any processing if debug is disabled. */
if (bglobal.debug_network == false)
return;
if (peer->sa_sin.sin_family)
snprintf(peerstr, sizeof(peerstr), " peer:%s", satostr(peer));
else
peerstr[0] = 0;
if (local->sa_sin.sin_family)
snprintf(localstr, sizeof(localstr), " local:%s",
satostr(local));
else
localstr[0] = 0;
if (ifindex != IFINDEX_INTERNAL)
snprintf(portstr, sizeof(portstr), " port:%u", ifindex);
else
portstr[0] = 0;
if (vrfid != VRF_DEFAULT)
snprintf(vrfstr, sizeof(vrfstr), " vrf:%u", vrfid);
else
vrfstr[0] = 0;
va_start(vl, fmt);
vsnprintf(buf, sizeof(buf), fmt, vl);
va_end(vl);
zlog_debug("control-packet: %s [mhop:%s%s%s%s%s]", buf,
mhop ? "yes" : "no", peerstr, localstr, portstr, vrfstr);
}
int bfd_recv_cb(struct thread *t)
{
int sd = THREAD_FD(t);
struct bfd_session *bfd;
struct bfd_pkt *cp;
bool is_mhop;
ssize_t mlen = 0;
uint8_t ttl = 0;
vrf_id_t vrfid;
ifindex_t ifindex = IFINDEX_INTERNAL;
struct sockaddr_any local, peer;
uint8_t msgbuf[1516];
struct interface *ifp = NULL;
struct bfd_vrf_global *bvrf = THREAD_ARG(t);
vrfid = bvrf->vrf->vrf_id;
/* Schedule next read. */
bfd_sd_reschedule(bvrf, sd);
/* Handle echo packets. */
if (sd == bvrf->bg_echo || sd == bvrf->bg_echov6) {
ptm_bfd_process_echo_pkt(bvrf, sd);
return 0;
}
/* Sanitize input/output. */
memset(&local, 0, sizeof(local));
memset(&peer, 0, sizeof(peer));
/* Handle control packets. */
is_mhop = false;
if (sd == bvrf->bg_shop || sd == bvrf->bg_mhop) {
is_mhop = sd == bvrf->bg_mhop;
mlen = bfd_recv_ipv4(sd, msgbuf, sizeof(msgbuf), &ttl, &ifindex,
&local, &peer);
} else if (sd == bvrf->bg_shop6 || sd == bvrf->bg_mhop6) {
is_mhop = sd == bvrf->bg_mhop6;
mlen = bfd_recv_ipv6(sd, msgbuf, sizeof(msgbuf), &ttl, &ifindex,
&local, &peer);
}
/* update vrf-id because when in vrf-lite mode,
* the socket is on default namespace
*/
if (ifindex) {
ifp = if_lookup_by_index(ifindex, vrfid);
if (ifp)
vrfid = ifp->vrf_id;
}
/* Implement RFC 5880 6.8.6 */
if (mlen < BFD_PKT_LEN) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"too small (%ld bytes)", mlen);
return 0;
}
/* Validate single hop packet TTL. */
if ((!is_mhop) && (ttl != BFD_TTL_VAL)) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"invalid TTL: %d expected %d", ttl, BFD_TTL_VAL);
return 0;
}
/*
* Parse the control header for inconsistencies:
* - Invalid version;
* - Bad multiplier configuration;
* - Short packets;
* - Invalid discriminator;
*/
cp = (struct bfd_pkt *)(msgbuf);
if (BFD_GETVER(cp->diag) != BFD_VERSION) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"bad version %d", BFD_GETVER(cp->diag));
return 0;
}
if (cp->detect_mult == 0) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"detect multiplier set to zero");
return 0;
}
if ((cp->len < BFD_PKT_LEN) || (cp->len > mlen)) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid, "too small");
return 0;
}
if (cp->discrs.my_discr == 0) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"'my discriminator' is zero");
return 0;
}
/* Find the session that this packet belongs. */
bfd = ptm_bfd_sess_find(cp, &peer, &local, ifindex, vrfid, is_mhop);
if (bfd == NULL) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"no session found");
return 0;
}
bfd->stats.rx_ctrl_pkt++;
/*
* Multi hop: validate packet TTL.
* Single hop: set local address that received the packet.
*/
if (is_mhop) {
if (ttl < bfd->mh_ttl) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"exceeded max hop count (expected %d, got %d)",
bfd->mh_ttl, ttl);
return 0;
}
} else if (bfd->local_address.sa_sin.sin_family == AF_UNSPEC) {
bfd->local_address = local;
}
/*
* If no interface was detected, save the interface where the
* packet came in.
*/
if (bfd->ifp == NULL)
bfd->ifp = if_lookup_by_index(ifindex, vrfid);
/* Log remote discriminator changes. */
if ((bfd->discrs.remote_discr != 0)
&& (bfd->discrs.remote_discr != ntohl(cp->discrs.my_discr)))
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"remote discriminator mismatch (expected %u, got %u)",
bfd->discrs.remote_discr, ntohl(cp->discrs.my_discr));
bfd->discrs.remote_discr = ntohl(cp->discrs.my_discr);
/* Save remote diagnostics before state switch. */
bfd->remote_diag = cp->diag & BFD_DIAGMASK;
/* Update remote timers settings. */
bfd->remote_timers.desired_min_tx = ntohl(cp->timers.desired_min_tx);
bfd->remote_timers.required_min_rx = ntohl(cp->timers.required_min_rx);
bfd->remote_timers.required_min_echo =
ntohl(cp->timers.required_min_echo);
bfd->remote_detect_mult = cp->detect_mult;
if (BFD_GETCBIT(cp->flags))
bfd->remote_cbit = 1;
else
bfd->remote_cbit = 0;
/* State switch from section 6.2. */
bs_state_handler(bfd, BFD_GETSTATE(cp->flags));
/* RFC 5880, Section 6.5: handle POLL/FINAL negotiation sequence. */
if (bfd->polling && BFD_GETFBIT(cp->flags)) {
/* Disable pooling. */
bfd->polling = 0;
/* Handle poll finalization. */
bs_final_handler(bfd);
} else {
/* Received a packet, lets update the receive timer. */
bfd_recvtimer_update(bfd);
}
/* Handle echo timers changes. */
bs_echo_timer_handler(bfd);
/*
* We've received a packet with the POLL bit set, we must send
* a control packet back with the FINAL bit set.
*
* RFC 5880, Section 6.5.
*/
if (BFD_GETPBIT(cp->flags)) {
/* We are finalizing a poll negotiation. */
bs_final_handler(bfd);
/* Send the control packet with the final bit immediately. */
ptm_bfd_snd(bfd, 1);
}
return 0;
}
/*
* bp_bfd_echo_in: proccesses an BFD echo packet. On TTL == BFD_TTL_VAL
* the packet is looped back or returns the my discriminator ID along
* with the TTL.
*
* Returns -1 on error or loopback or 0 on success.
*/
int bp_bfd_echo_in(struct bfd_vrf_global *bvrf, int sd,
uint8_t *ttl, uint32_t *my_discr)
{
struct bfd_echo_pkt *bep;
ssize_t rlen;
struct sockaddr_any local, peer;
ifindex_t ifindex = IFINDEX_INTERNAL;
vrf_id_t vrfid = VRF_DEFAULT;
uint8_t msgbuf[1516];
if (sd == bvrf->bg_echo)
rlen = bfd_recv_ipv4(sd, msgbuf, sizeof(msgbuf), ttl, &ifindex,
&local, &peer);
else
rlen = bfd_recv_ipv6(sd, msgbuf, sizeof(msgbuf), ttl, &ifindex,
&local, &peer);
/* Short packet, better not risk reading it. */
if (rlen < (ssize_t)sizeof(*bep)) {
cp_debug(false, &peer, &local, ifindex, vrfid,
"small echo packet");
return -1;
}
/* Test for loopback. */
if (*ttl == BFD_TTL_VAL) {
bp_udp_send(sd, *ttl - 1, msgbuf, rlen,
(struct sockaddr *)&peer,
(sd == bvrf->bg_echo) ? sizeof(peer.sa_sin)
: sizeof(peer.sa_sin6));
return -1;
}
/* Read my discriminator from BFD Echo packet. */
bep = (struct bfd_echo_pkt *)msgbuf;
*my_discr = ntohl(bep->my_discr);
if (*my_discr == 0) {
cp_debug(false, &peer, &local, ifindex, vrfid,
"invalid echo packet discriminator (zero)");
return -1;
}
return 0;
}
int bp_udp_send(int sd, uint8_t ttl, uint8_t *data, size_t datalen,
struct sockaddr *to, socklen_t tolen)
{
struct cmsghdr *cmsg;
ssize_t wlen;
int ttlval = ttl;
bool is_ipv6 = to->sa_family == AF_INET6;
struct msghdr msg;
struct iovec iov[1];
uint8_t msgctl[255];
/* Prepare message data. */
iov[0].iov_base = data;
iov[0].iov_len = datalen;
memset(&msg, 0, sizeof(msg));
memset(msgctl, 0, sizeof(msgctl));
msg.msg_name = to;
msg.msg_namelen = tolen;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
/* Prepare the packet TTL information. */
if (ttl > 0) {
/* Use ancillary data. */
msg.msg_control = msgctl;
msg.msg_controllen = CMSG_LEN(sizeof(ttlval));
/* Configure the ancillary data. */
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(ttlval));
if (is_ipv6) {
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_HOPLIMIT;
} else {
#ifdef BFD_LINUX
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_TTL;
#else
/* FreeBSD does not support TTL in ancillary data. */
msg.msg_control = NULL;
msg.msg_controllen = 0;
bp_set_ttl(sd, ttl);
#endif /* BFD_BSD */
}
memcpy(CMSG_DATA(cmsg), &ttlval, sizeof(ttlval));
}
/* Send echo back. */
wlen = sendmsg(sd, &msg, 0);
if (wlen <= 0) {
if (bglobal.debug_network)
zlog_debug("udp-send: loopback failure: (%d) %s", errno,
strerror(errno));
return -1;
} else if (wlen < (ssize_t)datalen) {
if (bglobal.debug_network)
zlog_debug("udp-send: partial send: %zd expected %zu",
wlen, datalen);
return -1;
}
return 0;
}
/*
* Sockets creation.
*/
/*
* IPv4 sockets
*/
int bp_set_ttl(int sd, uint8_t value)
{
int ttl = value;
if (setsockopt(sd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)) == -1) {
zlog_warn("set-ttl: setsockopt(IP_TTL, %d): %s", value,
strerror(errno));
return -1;
}
return 0;
}
int bp_set_tos(int sd, uint8_t value)
{
int tos = value;
if (setsockopt(sd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) == -1) {
zlog_warn("set-tos: setsockopt(IP_TOS, %d): %s", value,
strerror(errno));
return -1;
}
return 0;
}
static void bp_set_ipopts(int sd)
{
int rcvttl = BFD_RCV_TTL_VAL;
if (bp_set_ttl(sd, BFD_TTL_VAL) != 0)
zlog_fatal("set-ipopts: TTL configuration failed");
if (setsockopt(sd, IPPROTO_IP, IP_RECVTTL, &rcvttl, sizeof(rcvttl))
== -1)
zlog_fatal("set-ipopts: setsockopt(IP_RECVTTL, %d): %s", rcvttl,
strerror(errno));
#ifdef BFD_LINUX
int pktinfo = BFD_PKT_INFO_VAL;
/* Figure out address and interface to do the peer matching. */
if (setsockopt(sd, IPPROTO_IP, IP_PKTINFO, &pktinfo, sizeof(pktinfo))
== -1)
zlog_fatal("set-ipopts: setsockopt(IP_PKTINFO, %d): %s",
pktinfo, strerror(errno));
#endif /* BFD_LINUX */
#ifdef BFD_BSD
int yes = 1;
/* Find out our address for peer matching. */
if (setsockopt(sd, IPPROTO_IP, IP_RECVDSTADDR, &yes, sizeof(yes)) == -1)
zlog_fatal("set-ipopts: setsockopt(IP_RECVDSTADDR, %d): %s",
yes, strerror(errno));
/* Find out interface where the packet came in. */
if (setsockopt_ifindex(AF_INET, sd, yes) == -1)
zlog_fatal("set-ipopts: setsockopt_ipv4_ifindex(%d): %s", yes,
strerror(errno));
#endif /* BFD_BSD */
}
static void bp_bind_ip(int sd, uint16_t port)
{
struct sockaddr_in sin;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = htonl(INADDR_ANY);
sin.sin_port = htons(port);
if (bind(sd, (struct sockaddr *)&sin, sizeof(sin)) == -1)
zlog_fatal("bind-ip: bind: %s", strerror(errno));
}
int bp_udp_shop(const struct vrf *vrf)
{
int sd;
frr_with_privs(&bglobal.bfdd_privs) {
sd = vrf_socket(AF_INET, SOCK_DGRAM, PF_UNSPEC, vrf->vrf_id,
vrf->name);
}
if (sd == -1)
zlog_fatal("udp-shop: socket: %s", strerror(errno));
bp_set_ipopts(sd);
bp_bind_ip(sd, BFD_DEFDESTPORT);
return sd;
}
int bp_udp_mhop(const struct vrf *vrf)
{
int sd;
frr_with_privs(&bglobal.bfdd_privs) {
sd = vrf_socket(AF_INET, SOCK_DGRAM, PF_UNSPEC, vrf->vrf_id,
vrf->name);
}
if (sd == -1)
zlog_fatal("udp-mhop: socket: %s", strerror(errno));
bp_set_ipopts(sd);
bp_bind_ip(sd, BFD_DEF_MHOP_DEST_PORT);
return sd;
}
int bp_peer_socket(const struct bfd_session *bs)
{
int sd, pcount;
struct sockaddr_in sin;
static int srcPort = BFD_SRCPORTINIT;
const char *device_to_bind = NULL;
if (bs->key.ifname[0])
device_to_bind = (const char *)bs->key.ifname;
else if ((!vrf_is_backend_netns() && bs->vrf->vrf_id != VRF_DEFAULT)
|| ((CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH)
&& bs->key.vrfname[0])))
device_to_bind = (const char *)bs->key.vrfname;
frr_with_privs(&bglobal.bfdd_privs) {
sd = vrf_socket(AF_INET, SOCK_DGRAM, PF_UNSPEC,
bs->vrf->vrf_id, device_to_bind);
}
if (sd == -1) {
zlog_err("ipv4-new: failed to create socket: %s",
strerror(errno));
return -1;
}
/* Set TTL to 255 for all transmitted packets */
if (bp_set_ttl(sd, BFD_TTL_VAL) != 0) {
close(sd);
return -1;
}
/* Set TOS to CS6 for all transmitted packets */
if (bp_set_tos(sd, BFD_TOS_VAL) != 0) {
close(sd);
return -1;
}
/* Find an available source port in the proper range */
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
sin.sin_len = sizeof(sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
memcpy(&sin.sin_addr, &bs->key.local, sizeof(sin.sin_addr));
if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH) == 0)
sin.sin_addr.s_addr = INADDR_ANY;