summaryrefslogtreecommitdiffstats
path: root/bgpd/bgp_open.c
blob: 2a168899f78df2c39a5b1c04d135a2cb0f994d36 (plain)
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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
/* BGP open message handling
   Copyright (C) 1998, 1999 Kunihiro Ishiguro

This file is part of GNU Zebra.

GNU Zebra 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, or (at your option) any
later version.

GNU Zebra 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 GNU Zebra; see the file COPYING.  If not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

#include <zebra.h>

#include "linklist.h"
#include "prefix.h"
#include "stream.h"
#include "thread.h"
#include "log.h"
#include "command.h"
#include "memory.h"
#include "queue.h"

#include "lib/json.h"
#include "bgpd/bgpd.h"
#include "bgpd/bgp_attr.h"
#include "bgpd/bgp_debug.h"
#include "bgpd/bgp_fsm.h"
#include "bgpd/bgp_packet.h"
#include "bgpd/bgp_open.h"
#include "bgpd/bgp_aspath.h"
#include "bgpd/bgp_vty.h"

/* BGP-4 Multiprotocol Extentions lead us to the complex world. We can
   negotiate remote peer supports extentions or not. But if
   remote-peer doesn't supports negotiation process itself.  We would
   like to do manual configuration.

   So there is many configurable point.  First of all we want set each
   peer whether we send capability negotiation to the peer or not.
   Next, if we send capability to the peer we want to set my capabilty
   inforation at each peer. */

void
bgp_capability_vty_out (struct vty *vty, struct peer *peer, u_char use_json, json_object *json_neigh)
{
  char *pnt;
  char *end;
  struct capability_mp_data mpc;
  struct capability_header *hdr;
  json_object *json_cap = NULL;

  if (use_json)
    json_cap = json_object_new_object();

  pnt = peer->notify.data;
  end = pnt + peer->notify.length;
  
  while (pnt < end)
    {
      if (pnt + sizeof (struct capability_mp_data) + 2 > end)
	return;
      
      hdr = (struct capability_header *)pnt;
      if (pnt + hdr->length + 2 > end)
	return;

      memcpy (&mpc, pnt + 2, sizeof(struct capability_mp_data));

      if (hdr->code == CAPABILITY_CODE_MP)
	{
          if (use_json)
            {
              switch (ntohs (mpc.afi))
                {
                  case AFI_IP:
                    json_object_string_add(json_cap, "capabilityErrorMultiProtocolAfi", "IPv4");
                  break;
                  case AFI_IP6:
                    json_object_string_add(json_cap, "capabilityErrorMultiProtocolAfi", "IPv6");
                  break;
                  default:
                    json_object_int_add(json_cap, "capabilityErrorMultiProtocolAfiUnknown", ntohs (mpc.afi));
                  break;
                }
              switch (mpc.safi)
                {
                  case SAFI_UNICAST:
                    json_object_string_add(json_cap, "capabilityErrorMultiProtocolSafi", "unicast");
                  break;
                  case SAFI_MULTICAST:
                    json_object_string_add(json_cap, "capabilityErrorMultiProtocolSafi", "multicast");
                  break;
                  case SAFI_MPLS_LABELED_VPN:
                    json_object_string_add(json_cap, "capabilityErrorMultiProtocolSafi", "MPLS-labeled VPN");
                  break;
                  default:
                    json_object_int_add(json_cap, "capabilityErrorMultiProtocolSafiUnknown", mpc.safi);
                  break;
                }
            }
          else
            {
              vty_out (vty, "  Capability error for: Multi protocol ");
              switch (ntohs (mpc.afi))
                {
                  case AFI_IP:
                    vty_out (vty, "AFI IPv4, ");
                  break;
                  case AFI_IP6:
                    vty_out (vty, "AFI IPv6, ");
                  break;
                  default:
                    vty_out (vty, "AFI Unknown %d, ", ntohs (mpc.afi));
                  break;
                }
              switch (mpc.safi)
                {
                  case SAFI_UNICAST:
                    vty_out (vty, "SAFI Unicast");
                  break;
                  case SAFI_MULTICAST:
                    vty_out (vty, "SAFI Multicast");
                  break;
                 case SAFI_MPLS_LABELED_VPN:
                    vty_out (vty, "SAFI MPLS-labeled VPN");
                  break;
                  default:
                    vty_out (vty, "SAFI Unknown %d ", mpc.safi);
                  break;
                }
              vty_out (vty, "%s", VTY_NEWLINE);
            }
        }
      else if (hdr->code >= 128)
        {
          if (use_json)
            json_object_int_add(json_cap, "capabilityErrorVendorSpecificCapabilityCode", hdr->code);
          else
            vty_out (vty, "  Capability error: vendor specific capability code %d",
                     hdr->code);
        }
      else
        {
          if (use_json)
            json_object_int_add(json_cap, "capabilityErrorUnknownCapabilityCode", hdr->code);
          else
            vty_out (vty, "  Capability error: unknown capability code %d",
                     hdr->code);
        }
      pnt += hdr->length + 2;
    }
  if (use_json)
    json_object_object_add(json_neigh, "capabilityErrors", json_cap);
}

static void 
bgp_capability_mp_data (struct stream *s, struct capability_mp_data *mpc)
{
  mpc->afi = stream_getw (s);
  mpc->reserved = stream_getc (s);
  mpc->safi = stream_getc (s);
}

int
bgp_afi_safi_valid_indices (afi_t afi, safi_t *safi)
{
  switch (afi)
    {
      case AFI_IP:
#ifdef HAVE_IPV6
      case AFI_IP6:
#endif
        switch (*safi)
          {
            /* BGP MPLS-labeled VPN SAFI isn't contigious with others, remap */
            case SAFI_MPLS_LABELED_VPN:
              *safi = SAFI_MPLS_VPN;
            case SAFI_UNICAST:
            case SAFI_MULTICAST:
            case SAFI_MPLS_VPN:
              return 1;
          }
    }
  zlog_debug ("unknown afi/safi (%u/%u)", afi, *safi);
  
  return 0;
}

/* Set negotiated capability value. */
static int
bgp_capability_mp (struct peer *peer, struct capability_header *hdr)
{
  struct capability_mp_data mpc;
  struct stream *s = BGP_INPUT (peer);
  
  /* Verify length is 4 */
  if (hdr->length != 4)
    {
      zlog_warn("MP Cap: Received invalid length %d, non-multiple of 4",
		hdr->length);
      return -1;
    }

  bgp_capability_mp_data (s, &mpc);
  
  if (bgp_debug_neighbor_events(peer))
    zlog_debug ("%s OPEN has MP_EXT CAP for afi/safi: %u/%u",
               peer->host, mpc.afi, mpc.safi);
  
  if (!bgp_afi_safi_valid_indices (mpc.afi, &mpc.safi))
    return -1;
   
  /* Now safi remapped, and afi/safi are valid array indices */
  peer->afc_recv[mpc.afi][mpc.safi] = 1;
  
  if (peer->afc[mpc.afi][mpc.safi])
    peer->afc_nego[mpc.afi][mpc.safi] = 1;
  else 
    return -1;

  return 0;
}

static void
bgp_capability_orf_not_support (struct peer *peer, afi_t afi, safi_t safi,
				u_char type, u_char mode)
{
  if (bgp_debug_neighbor_events(peer))
    zlog_debug ("%s Addr-family %d/%d has ORF type/mode %d/%d not supported",
	       peer->host, afi, safi, type, mode);
}

static const struct message orf_type_str[] =
{
  { ORF_TYPE_PREFIX,		"Prefixlist"		},
  { ORF_TYPE_PREFIX_OLD,	"Prefixlist (old)"	},
};
static const int orf_type_str_max = array_size(orf_type_str);

static const struct message orf_mode_str[] =
{
  { ORF_MODE_RECEIVE,	"Receive"	},
  { ORF_MODE_SEND,	"Send"		},
  { ORF_MODE_BOTH,	"Both"		},
};
static const int orf_mode_str_max = array_size(orf_mode_str);

static int
bgp_capability_orf_entry (struct peer *peer, struct capability_header *hdr)
{
  struct stream *s = BGP_INPUT (peer);
  struct capability_orf_entry entry;
  afi_t afi;
  safi_t safi;
  u_char type;
  u_char mode;
  u_int16_t sm_cap = 0; /* capability send-mode receive */
  u_int16_t rm_cap = 0; /* capability receive-mode receive */ 
  int i;

  /* ORF Entry header */
  bgp_capability_mp_data (s, &entry.mpc);
  entry.num = stream_getc (s);
  afi = entry.mpc.afi;
  safi = entry.mpc.safi;
  
  if (bgp_debug_neighbor_events(peer))
    zlog_debug ("%s ORF Cap entry for afi/safi: %u/%u",
	        peer->host, entry.mpc.afi, entry.mpc.safi);

  /* Check AFI and SAFI. */
  if (!bgp_afi_safi_valid_indices (entry.mpc.afi, &safi))
    {
      zlog_info ("%s Addr-family %d/%d not supported."
                 " Ignoring the ORF capability",
                 peer->host, entry.mpc.afi, entry.mpc.safi);
      return 0;
    }
  
  /* validate number field */
  if (sizeof (struct capability_orf_entry) + (entry.num * 2) > hdr->length)
    {
      zlog_info ("%s ORF Capability entry length error,"
                 " Cap length %u, num %u",
                 peer->host, hdr->length, entry.num);
      bgp_notify_send (peer, BGP_NOTIFY_CEASE, BGP_NOTIFY_OPEN_MALFORMED_ATTR);
      return -1;
    }

  for (i = 0 ; i < entry.num ; i++)
    {
      type = stream_getc(s);
      mode = stream_getc(s);
      
      /* ORF Mode error check */
      switch (mode)
        {
          case ORF_MODE_BOTH:
          case ORF_MODE_SEND:
          case ORF_MODE_RECEIVE:
            break;
          default:
	    bgp_capability_orf_not_support (peer, afi, safi, type, mode);
	    continue;
	}
      /* ORF Type and afi/safi error checks */
      /* capcode versus type */
      switch (hdr->code)
        {
          case CAPABILITY_CODE_ORF:
            switch (type)
              {
                case ORF_TYPE_PREFIX:
                  break;
                default:
                  bgp_capability_orf_not_support (peer, afi, safi, type, mode);
                  continue;
              }
            break;
          case CAPABILITY_CODE_ORF_OLD:
            switch (type)
              {
                case ORF_TYPE_PREFIX_OLD:
                  break;
                default:
                  bgp_capability_orf_not_support (peer, afi, safi, type, mode);
                  continue;
              }
            break;
          default:
            bgp_capability_orf_not_support (peer, afi, safi, type, mode);
            continue;
        }
                
      /* AFI vs SAFI */
      if (!((afi == AFI_IP && safi == SAFI_UNICAST)
            || (afi == AFI_IP && safi == SAFI_MULTICAST)
            || (afi == AFI_IP6 && safi == SAFI_UNICAST)))
        {
          bgp_capability_orf_not_support (peer, afi, safi, type, mode);
          continue;
        }
      
      if (bgp_debug_neighbor_events(peer))
        zlog_debug ("%s OPEN has %s ORF capability"
                    " as %s for afi/safi: %d/%d",
                    peer->host, LOOKUP (orf_type_str, type),
                    LOOKUP (orf_mode_str, mode),
                    entry.mpc.afi, safi);

      if (hdr->code == CAPABILITY_CODE_ORF)
	{
          sm_cap = PEER_CAP_ORF_PREFIX_SM_RCV;
          rm_cap = PEER_CAP_ORF_PREFIX_RM_RCV;
	}
      else if (hdr->code == CAPABILITY_CODE_ORF_OLD)
	{
          sm_cap = PEER_CAP_ORF_PREFIX_SM_OLD_RCV;
          rm_cap = PEER_CAP_ORF_PREFIX_RM_OLD_RCV;
	}
      else
	{
	  bgp_capability_orf_not_support (peer, afi, safi, type, mode);
	  continue;
	}

      switch (mode)
	{
	  case ORF_MODE_BOTH:
	    SET_FLAG (peer->af_cap[afi][safi], sm_cap);
	    SET_FLAG (peer->af_cap[afi][safi], rm_cap);
	    break;
	  case ORF_MODE_SEND:
	    SET_FLAG (peer->af_cap[afi][safi], sm_cap);
	    break;
	  case ORF_MODE_RECEIVE:
	    SET_FLAG (peer->af_cap[afi][safi], rm_cap);
	    break;
	}
    }
  return 0;
}

static int
bgp_capability_restart (struct peer *peer, struct capability_header *caphdr)
{
  struct stream *s = BGP_INPUT (peer);
  u_int16_t restart_flag_time;
  int restart_bit = 0;
  size_t end = stream_get_getp (s) + caphdr->length;

  /* Verify length is a multiple of 4 */
  if ((caphdr->length-2) % 4)
    {
      zlog_warn("Restart Cap: Received invalid length %d, non-multiple of 4",
		caphdr->length);
      return -1;
    }

  SET_FLAG (peer->cap, PEER_CAP_RESTART_RCV);
  restart_flag_time = stream_getw(s);
  if (CHECK_FLAG (restart_flag_time, RESTART_R_BIT))
    {
      SET_FLAG (peer->cap, PEER_CAP_RESTART_BIT_RCV);
      restart_bit = 1;
    }
  UNSET_FLAG (restart_flag_time, 0xF000);
  peer->v_gr_restart = restart_flag_time;

  if (bgp_debug_neighbor_events(peer))
    {
      zlog_debug ("%s OPEN has Graceful Restart capability", peer->host);
      zlog_debug ("%s Peer has%srestarted. Restart Time : %d",
                  peer->host, restart_bit ? " " : " not ",
                  peer->v_gr_restart);
    }

  while (stream_get_getp (s) + 4 <= end)
    {
      afi_t afi = stream_getw (s);
      safi_t safi = stream_getc (s);
      u_char flag = stream_getc (s);
      
      if (!bgp_afi_safi_valid_indices (afi, &safi))
        {
          if (bgp_debug_neighbor_events(peer))
            zlog_debug ("%s Addr-family %d/%d(afi/safi) not supported."
                        " Ignore the Graceful Restart capability for this AFI/SAFI",
                        peer->host, afi, safi);
        }
      else if (!peer->afc[afi][safi])
        {
          if (bgp_debug_neighbor_events(peer))
            zlog_debug ("%s Addr-family %d/%d(afi/safi) not enabled."
                        " Ignore the Graceful Restart capability",
                        peer->host, afi, safi);
        }
      else
        {
          if (bgp_debug_neighbor_events(peer))
            zlog_debug ("%s Address family %s is%spreserved", peer->host,
                        afi_safi_print (afi, safi),
                        CHECK_FLAG (peer->af_cap[afi][safi],
                                    PEER_CAP_RESTART_AF_PRESERVE_RCV)
                        ? " " : " not ");

          SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_RESTART_AF_RCV);
          if (CHECK_FLAG (flag, RESTART_F_BIT))
            SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_RESTART_AF_PRESERVE_RCV);
          
        }
    }
  return 0;
}

/* Unlike other capability parsing routines, this one returns 0 on error */
static as_t
bgp_capability_as4 (struct peer *peer, struct capability_header *hdr)
{
  SET_FLAG (peer->cap, PEER_CAP_AS4_RCV);
  
  if (hdr->length != CAPABILITY_CODE_AS4_LEN)
    {
      zlog_err ("%s AS4 capability has incorrect data length %d",
                peer->host, hdr->length);
      return 0;
    }
  
  as_t as4 = stream_getl (BGP_INPUT(peer));
  
  if (BGP_DEBUG (as4, AS4))
    zlog_debug ("%s [AS4] about to set cap PEER_CAP_AS4_RCV, got as4 %u",
                peer->host, as4);
  return as4;
}

static int
bgp_capability_addpath (struct peer *peer, struct capability_header *hdr)
{
  struct stream *s = BGP_INPUT (peer);
  size_t end = stream_get_getp (s) + hdr->length;

  SET_FLAG (peer->cap, PEER_CAP_ADDPATH_RCV);

  /* Verify length is a multiple of 4 */
  if (hdr->length % 4)
    {
      zlog_warn("Add Path: Received invalid length %d, non-multiple of 4",
		hdr->length);
      return -1;
    }

  while (stream_get_getp (s) + 4 <= end)
    {
      afi_t afi = stream_getw (s);
      safi_t safi = stream_getc (s);
      u_char send_receive = stream_getc (s);

      if (bgp_debug_neighbor_events(peer))
        zlog_debug ("%s OPEN has AddPath CAP for afi/safi: %u/%u%s%s",
                    peer->host, afi, safi,
                    (send_receive & BGP_ADDPATH_RX) ? ", receive" : "",
                    (send_receive & BGP_ADDPATH_TX) ? ", transmit" : "");

      if (!bgp_afi_safi_valid_indices (afi, &safi))
        {
          if (bgp_debug_neighbor_events(peer))
            zlog_debug ("%s Addr-family %d/%d(afi/safi) not supported."
                        " Ignore the Addpath Attribute for this AFI/SAFI",
                        peer->host, afi, safi);
	  continue;
        }
      else if (!peer->afc[afi][safi])
        {
          if (bgp_debug_neighbor_events(peer))
            zlog_debug ("%s Addr-family %d/%d(afi/safi) not enabled."
                        " Ignore the AddPath capability for this AFI/SAFI",
                        peer->host, afi, safi);
	  continue;
        }

      if (send_receive & BGP_ADDPATH_RX)
        SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ADDPATH_AF_RX_RCV);

      if (send_receive & BGP_ADDPATH_TX)
        SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ADDPATH_AF_TX_RCV);
    }

  return 0;
}

static int
bgp_capability_enhe (struct peer *peer, struct capability_header *hdr)
{
  struct stream *s = BGP_INPUT (peer);
  size_t end = stream_get_getp (s) + hdr->length;

  /* Verify length is a multiple of 4 */
  if (hdr->length % 6)
    {
      zlog_warn("Extended NH: Received invalid length %d, non-multiple of 6",
		hdr->length);
      return -1;
    }

  while (stream_get_getp (s) + 6 <= end)
    {
      afi_t afi = stream_getw (s);
      safi_t safi = stream_getw (s);
      afi_t nh_afi = stream_getw (s);

      if (bgp_debug_neighbor_events(peer))
        zlog_debug ("%s   Received with value triple (afi/safi/next-hop afi): %u/%u/%u",
                    peer->host, afi, safi, nh_afi);

      if (!bgp_afi_safi_valid_indices (afi, &safi))
        return -1;

      if (afi != AFI_IP || nh_afi != AFI_IP6)
        {
          zlog_warn ("%s Extended Next-hop capability, wrong afi/next-hop afi: %u/%u",
                     peer->host, afi, nh_afi);
          return -1;
        }

      /* Until SAFIs other than SAFI_UNICAST are supported */
      if (safi != SAFI_UNICAST)
        zlog_warn ("%s Extended Next-hop capability came with unsupported SAFI: %u",
                   peer->host, safi);

      SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ENHE_AF_RCV);

      if (CHECK_FLAG (peer->af_cap[afi][safi], PEER_CAP_ENHE_AF_ADV))
        SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ENHE_AF_NEGO);
    }

  SET_FLAG (peer->cap, PEER_CAP_ENHE_RCV);

  return 0;
}

static int
bgp_capability_hostname (struct peer *peer, struct capability_header *hdr)
{
  struct stream *s = BGP_INPUT (peer);
  char str[BGP_MAX_HOSTNAME+1];
  size_t end = stream_get_getp (s) + hdr->length;
  u_char len;

  SET_FLAG(peer->cap, PEER_CAP_HOSTNAME_RCV);

  len = stream_getc(s);
  if (stream_get_getp(s) + len > end)
    {
      zlog_warn("%s: Received malformed hostname capability from peer %s",
                __FUNCTION__, peer->host);
      return -1;
    }

  if (len > BGP_MAX_HOSTNAME)
    {
      stream_get(str, s, BGP_MAX_HOSTNAME);
      stream_forward_getp(s, len-BGP_MAX_HOSTNAME);
      len = BGP_MAX_HOSTNAME;   /* to set the '\0' below */
    }
  else if (len)
    stream_get(str, s, len);

  if (len)
    {
      str[len] = '\0';

      if (peer->hostname != NULL)
        XFREE(MTYPE_HOST, peer->hostname);

      if (peer->domainname != NULL)
        {
          XFREE(MTYPE_HOST, peer->domainname);
          peer->domainname = NULL;
        }

      peer->hostname = XSTRDUP(MTYPE_HOST, str);
    }

  if (stream_get_getp(s) +1 > end)
    {
      zlog_warn("%s: Received invalid domain name len (hostname capability) from peer %s",
                __FUNCTION__, peer->host);
      return -1;
    }

  len = stream_getc(s);
  if (stream_get_getp(s) + len > end)
    {
      zlog_warn("%s: Received runt domain name (hostname capability) from peer %s",
                __FUNCTION__, peer->host);
      return -1;
    }

  if (len > BGP_MAX_HOSTNAME)
    {
      stream_get(str, s, BGP_MAX_HOSTNAME);
      stream_forward_getp(s, len-BGP_MAX_HOSTNAME);
      len = BGP_MAX_HOSTNAME;   /* to set the '\0' below */
    }
  else if (len)
    stream_get(str, s, len);

  if (len)
    {
      str[len] = '\0';
      peer->domainname = XSTRDUP(MTYPE_HOST, str);
    }

  if (bgp_debug_neighbor_events(peer))
    {
      zlog_debug("%s received hostname %s, domainname %s",
                 peer->host, peer->hostname, peer->domainname);
    }

  return 0;
}

  static const struct message capcode_str[] =
{
  { CAPABILITY_CODE_MP,			"MultiProtocol Extensions"	},
  { CAPABILITY_CODE_REFRESH,		"Route Refresh"			},
  { CAPABILITY_CODE_ORF,		"Cooperative Route Filtering" 	},
  { CAPABILITY_CODE_RESTART,		"Graceful Restart"		},
  { CAPABILITY_CODE_AS4,		"4-octet AS number"		},
  { CAPABILITY_CODE_ADDPATH,            "AddPath"                       },
  { CAPABILITY_CODE_DYNAMIC,		"Dynamic"			},
  { CAPABILITY_CODE_ENHE,               "Extended Next Hop Encoding"    },
  { CAPABILITY_CODE_DYNAMIC_OLD,	"Dynamic (Old)"			},
  { CAPABILITY_CODE_REFRESH_OLD,	"Route Refresh (Old)"		},
  { CAPABILITY_CODE_ORF_OLD,		"ORF (Old)"			},
  { CAPABILITY_CODE_FQDN,               "FQDN"                          },
};
static const int capcode_str_max = array_size(capcode_str);

/* Minimum sizes for length field of each cap (so not inc. the header) */
static const size_t cap_minsizes[] = 
{
  [CAPABILITY_CODE_MP]		= sizeof (struct capability_mp_data),
  [CAPABILITY_CODE_REFRESH]	= CAPABILITY_CODE_REFRESH_LEN,
  [CAPABILITY_CODE_ORF]		= sizeof (struct capability_orf_entry),
  [CAPABILITY_CODE_RESTART]	= sizeof (struct capability_gr),
  [CAPABILITY_CODE_AS4]		= CAPABILITY_CODE_AS4_LEN,
  [CAPABILITY_CODE_ADDPATH]     = CAPABILITY_CODE_ADDPATH_LEN,
  [CAPABILITY_CODE_DYNAMIC]	= CAPABILITY_CODE_DYNAMIC_LEN,
  [CAPABILITY_CODE_DYNAMIC_OLD]	= CAPABILITY_CODE_DYNAMIC_LEN,
  [CAPABILITY_CODE_ENHE]        = CAPABILITY_CODE_ENHE_LEN,
  [CAPABILITY_CODE_REFRESH_OLD]	= CAPABILITY_CODE_REFRESH_LEN,
  [CAPABILITY_CODE_ORF_OLD]	= sizeof (struct capability_orf_entry),
  [CAPABILITY_CODE_FQDN]        = CAPABILITY_CODE_MIN_FQDN_LEN,
};

/**
 * Parse given capability.
 * XXX: This is reading into a stream, but not using stream API
 *
 * @param[out] mp_capability Set to 1 on return iff one or more Multiprotocol
 *                           capabilities were encountered.
 */
static int
bgp_capability_parse (struct peer *peer, size_t length, int *mp_capability,
		      u_char **error)
{
  int ret;
  struct stream *s = BGP_INPUT (peer);
  size_t end = stream_get_getp (s) + length;
  
  assert (STREAM_READABLE (s) >= length);
  
  while (stream_get_getp (s) < end)
    {
      size_t start;
      u_char *sp = stream_pnt (s);
      struct capability_header caphdr;

      ret = 0;
      /* We need at least capability code and capability length. */
      if (stream_get_getp(s) + 2 > end)
	{
	  zlog_info ("%s Capability length error (< header)", peer->host);
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE, BGP_NOTIFY_OPEN_MALFORMED_ATTR);
	  return -1;
	}
      
      caphdr.code = stream_getc (s);
      caphdr.length = stream_getc (s);
      start = stream_get_getp (s);
      
      /* Capability length check sanity check. */
      if (start + caphdr.length > end)
	{
	  zlog_info ("%s Capability length error (< length)", peer->host);
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE, BGP_NOTIFY_OPEN_MALFORMED_ATTR);
	  return -1;
	}
      
      if (bgp_debug_neighbor_events(peer))
	zlog_debug ("%s OPEN has %s capability (%u), length %u",
		   peer->host,
		   LOOKUP (capcode_str, caphdr.code),
		   caphdr.code, caphdr.length);
      
      /* Length sanity check, type-specific, for known capabilities */
      switch (caphdr.code)
        {
          case CAPABILITY_CODE_MP:
          case CAPABILITY_CODE_REFRESH:
          case CAPABILITY_CODE_REFRESH_OLD:
          case CAPABILITY_CODE_ORF:
          case CAPABILITY_CODE_ORF_OLD:
          case CAPABILITY_CODE_RESTART:
          case CAPABILITY_CODE_AS4:
          case CAPABILITY_CODE_ADDPATH:
          case CAPABILITY_CODE_DYNAMIC:
          case CAPABILITY_CODE_DYNAMIC_OLD:
          case CAPABILITY_CODE_ENHE:
	  case CAPABILITY_CODE_FQDN:
              /* Check length. */
              if (caphdr.length < cap_minsizes[caphdr.code])
                {
                  zlog_info ("%s %s Capability length error: got %u,"
                             " expected at least %u",
                             peer->host, 
                             LOOKUP (capcode_str, caphdr.code),
                             caphdr.length, 
			     (unsigned) cap_minsizes[caphdr.code]);
                  bgp_notify_send (peer, BGP_NOTIFY_CEASE, BGP_NOTIFY_OPEN_MALFORMED_ATTR);
                  return -1;
                }
          /* we deliberately ignore unknown codes, see below */
          default:
            break;
        }
      
      switch (caphdr.code)
        {
          case CAPABILITY_CODE_MP:
            {
	      *mp_capability = 1;

              /* Ignore capability when override-capability is set. */
              if (! CHECK_FLAG (peer->flags, PEER_FLAG_OVERRIDE_CAPABILITY))
                {
                  /* Set negotiated value. */
                  ret = bgp_capability_mp (peer, &caphdr);

                  /* Unsupported Capability. */
                  if (ret < 0)
                    {
                      /* Store return data. */
                      memcpy (*error, sp, caphdr.length + 2);
                      *error += caphdr.length + 2;
                    }
		  ret = 0;	/* Don't return error for this */
                }
            }
            break;
          case CAPABILITY_CODE_REFRESH:
          case CAPABILITY_CODE_REFRESH_OLD:
            {
              /* BGP refresh capability */
              if (caphdr.code == CAPABILITY_CODE_REFRESH_OLD)
                SET_FLAG (peer->cap, PEER_CAP_REFRESH_OLD_RCV);
              else
                SET_FLAG (peer->cap, PEER_CAP_REFRESH_NEW_RCV);
            }
            break;
          case CAPABILITY_CODE_ORF:
          case CAPABILITY_CODE_ORF_OLD:
            ret = bgp_capability_orf_entry (peer, &caphdr);
            break;
          case CAPABILITY_CODE_RESTART:
            ret = bgp_capability_restart (peer, &caphdr);
            break;
          case CAPABILITY_CODE_DYNAMIC:
	  case CAPABILITY_CODE_DYNAMIC_OLD:
            SET_FLAG (peer->cap, PEER_CAP_DYNAMIC_RCV);
            break;
          case CAPABILITY_CODE_AS4:
              /* Already handled as a special-case parsing of the capabilities
               * at the beginning of OPEN processing. So we care not a jot
               * for the value really, only error case.
               */
              if (!bgp_capability_as4 (peer, &caphdr))
                ret = -1;
              break;            
          case CAPABILITY_CODE_ADDPATH:
            ret = bgp_capability_addpath (peer, &caphdr);
            break;
          case CAPABILITY_CODE_ENHE:
            ret = bgp_capability_enhe (peer, &caphdr);
            break;
	  case CAPABILITY_CODE_FQDN:
	    ret = bgp_capability_hostname (peer, &caphdr);
	    break;
          default:
            if (caphdr.code > 128)
              {
                /* We don't send Notification for unknown vendor specific
                   capabilities.  It seems reasonable for now...  */
                zlog_warn ("%s Vendor specific capability %d",
                           peer->host, caphdr.code);
              }
            else
              {
                zlog_warn ("%s unrecognized capability code: %d - ignored",
                           peer->host, caphdr.code);
                memcpy (*error, sp, caphdr.length + 2);
                *error += caphdr.length + 2;
              }
          }

      if (ret < 0)
	{
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE, BGP_NOTIFY_OPEN_MALFORMED_ATTR);
	  return -1;
	}
      if (stream_get_getp(s) != (start + caphdr.length))
        {
          if (stream_get_getp(s) > (start + caphdr.length))
            zlog_warn ("%s Cap-parser for %s read past cap-length, %u!",
                       peer->host, LOOKUP (capcode_str, caphdr.code),
                       caphdr.length);
          stream_set_getp (s, start + caphdr.length);
        }
    }
  return 0;
}

static int
bgp_auth_parse (struct peer *peer, size_t length)
{
  bgp_notify_send (peer, 
		   BGP_NOTIFY_OPEN_ERR, 
		   BGP_NOTIFY_OPEN_AUTH_FAILURE); 
  return -1;
}

static int
strict_capability_same (struct peer *peer)
{
  int i, j;

  for (i = AFI_IP; i < AFI_MAX; i++)
    for (j = SAFI_UNICAST; j < SAFI_MAX; j++)
      if (peer->afc[i][j] != peer->afc_nego[i][j])
	return 0;
  return 1;
}

/* peek into option, stores ASN to *as4 if the AS4 capability was found.
 * Returns  0 if no as4 found, as4cap value otherwise.
 */
as_t
peek_for_as4_capability (struct peer *peer, u_char length)
{
  struct stream *s = BGP_INPUT (peer);
  size_t orig_getp = stream_get_getp (s);
  size_t end = orig_getp + length;
  as_t as4 = 0;
  
  /* The full capability parser will better flag the error.. */
  if (STREAM_READABLE(s) < length)
    return 0;

  if (BGP_DEBUG (as4, AS4))
    zlog_info ("%s [AS4] rcv OPEN w/ OPTION parameter len: %u,"
                " peeking for as4",
	        peer->host, length);
  /* the error cases we DONT handle, we ONLY try to read as4 out of
   * correctly formatted options.
   */
  while (stream_get_getp(s) < end) 
    {
      u_char opt_type;
      u_char opt_length;
      
      /* Check the length. */
      if (stream_get_getp (s) + 2 > end)
        goto end;
      
      /* Fetch option type and length. */
      opt_type = stream_getc (s);
      opt_length = stream_getc (s);
      
      /* Option length check. */
      if (stream_get_getp (s) + opt_length > end)
        goto end;
      
      if (opt_type == BGP_OPEN_OPT_CAP)
        {
          unsigned long capd_start = stream_get_getp (s);
          unsigned long capd_end = capd_start + opt_length;
          
          assert (capd_end <= end);
          
	  while (stream_get_getp (s) < capd_end)
	    {
	      struct capability_header hdr;
	      
	      if (stream_get_getp (s) + 2 > capd_end)
                goto end;
              
              hdr.code = stream_getc (s);
              hdr.length = stream_getc (s);
              
	      if ((stream_get_getp(s) +  hdr.length) > capd_end)
		goto end;

	      if (hdr.code == CAPABILITY_CODE_AS4)
	        {
	          if (BGP_DEBUG (as4, AS4))
	            zlog_info ("[AS4] found AS4 capability, about to parse");
	          as4 = bgp_capability_as4 (peer, &hdr);
	          
	          goto end;
                }
              stream_forward_getp (s, hdr.length);
	    }
	}
    }

end:
  stream_set_getp (s, orig_getp);
  return as4;
}

/**
 * Parse open option.
 *
 * @param[out] mp_capability @see bgp_capability_parse() for semantics.
 */
int
bgp_open_option_parse (struct peer *peer, u_char length, int *mp_capability)
{
  int ret;
  u_char *error;
  u_char error_data[BGP_MAX_PACKET_SIZE];
  struct stream *s = BGP_INPUT(peer);
  size_t end = stream_get_getp (s) + length;

  ret = 0;
  error = error_data;

  if (bgp_debug_neighbor_events(peer))
    zlog_debug ("%s rcv OPEN w/ OPTION parameter len: %u",
	       peer->host, length);
  
  while (stream_get_getp(s) < end)
    {
      u_char opt_type;
      u_char opt_length;
      
      /* Must have at least an OPEN option header */
      if (STREAM_READABLE(s) < 2)
	{
	  zlog_info ("%s Option length error", peer->host);
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE, BGP_NOTIFY_OPEN_MALFORMED_ATTR);
	  return -1;
	}

      /* Fetch option type and length. */
      opt_type = stream_getc (s);
      opt_length = stream_getc (s);
      
      /* Option length check. */
      if (STREAM_READABLE (s) < opt_length)
	{
	  zlog_info ("%s Option length error", peer->host);
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE, BGP_NOTIFY_OPEN_MALFORMED_ATTR);
	  return -1;
	}

      if (bgp_debug_neighbor_events(peer))
	zlog_debug ("%s rcvd OPEN w/ optional parameter type %u (%s) len %u",
		   peer->host, opt_type,
		   opt_type == BGP_OPEN_OPT_AUTH ? "Authentication" :
		   opt_type == BGP_OPEN_OPT_CAP ? "Capability" : "Unknown",
		   opt_length);
  
      switch (opt_type)
	{
	case BGP_OPEN_OPT_AUTH:
	  ret = bgp_auth_parse (peer, opt_length);
	  break;
	case BGP_OPEN_OPT_CAP:
	  ret = bgp_capability_parse (peer, opt_length, mp_capability, &error);
	  break;
	default:
	  bgp_notify_send (peer, 
			   BGP_NOTIFY_OPEN_ERR, 
			   BGP_NOTIFY_OPEN_UNSUP_PARAM); 
	  ret = -1;
	  break;
	}

      /* Parse error.  To accumulate all unsupported capability codes,
         bgp_capability_parse does not return -1 when encounter
         unsupported capability code.  To detect that, please check
         error and erro_data pointer, like below.  */
      if (ret < 0)
	return -1;
    }

  /* All OPEN option is parsed.  Check capability when strict compare
     flag is enabled.*/
  if (CHECK_FLAG (peer->flags, PEER_FLAG_STRICT_CAP_MATCH))
    {
      /* If Unsupported Capability exists. */
      if (error != error_data)
	{
	  bgp_notify_send_with_data (peer, 
				     BGP_NOTIFY_OPEN_ERR, 
				     BGP_NOTIFY_OPEN_UNSUP_CAPBL, 
				     error_data, error - error_data);
	  return -1;
	}

      /* Check local capability does not negotiated with remote
         peer. */
      if (! strict_capability_same (peer))
	{
	  bgp_notify_send (peer, 
			   BGP_NOTIFY_OPEN_ERR, 
			   BGP_NOTIFY_OPEN_UNSUP_CAPBL);
	  return -1;
	}
    }

  /* Check there are no common AFI/SAFIs and send Unsupported Capability
     error. */
  if (*mp_capability &&
      ! CHECK_FLAG (peer->flags, PEER_FLAG_OVERRIDE_CAPABILITY))
    {
      if (! peer->afc_nego[AFI_IP][SAFI_UNICAST] 
	  && ! peer->afc_nego[AFI_IP][SAFI_MULTICAST]
	  && ! peer->afc_nego[AFI_IP][SAFI_MPLS_VPN]
	  && ! peer->afc_nego[AFI_IP6][SAFI_UNICAST]
	  && ! peer->afc_nego[AFI_IP6][SAFI_MULTICAST])
	{
	  zlog_err ("%s [Error] Configured AFI/SAFIs do not "
		    "overlap with received MP capabilities",
		    peer->host);

	  if (error != error_data)
	    bgp_notify_send_with_data (peer, 
				       BGP_NOTIFY_OPEN_ERR, 
				       BGP_NOTIFY_OPEN_UNSUP_CAPBL, 
				       error_data, error - error_data);
	  else
	    bgp_notify_send (peer, 
			     BGP_NOTIFY_OPEN_ERR, 
			     BGP_NOTIFY_OPEN_UNSUP_CAPBL);
	  return -1;
	}
    }
  return 0;
}

static void
bgp_open_capability_orf (struct stream *s, struct peer *peer,
                         afi_t afi, safi_t safi, u_char code)
{
  u_char cap_len;
  u_char orf_len;
  unsigned long capp;
  unsigned long orfp;
  unsigned long numberp;
  int number_of_orfs = 0;

  if (safi == SAFI_MPLS_VPN)
    safi = SAFI_MPLS_LABELED_VPN;

  stream_putc (s, BGP_OPEN_OPT_CAP);
  capp = stream_get_endp (s);           /* Set Capability Len Pointer */
  stream_putc (s, 0);                   /* Capability Length */
  stream_putc (s, code);                /* Capability Code */
  orfp = stream_get_endp (s);           /* Set ORF Len Pointer */
  stream_putc (s, 0);                   /* ORF Length */
  stream_putw (s, afi);
  stream_putc (s, 0);
  stream_putc (s, safi);
  numberp = stream_get_endp (s);        /* Set Number Pointer */
  stream_putc (s, 0);                   /* Number of ORFs */

  /* Address Prefix ORF */
  if (CHECK_FLAG (peer->af_flags[afi][safi], PEER_FLAG_ORF_PREFIX_SM)
      || CHECK_FLAG (peer->af_flags[afi][safi], PEER_FLAG_ORF_PREFIX_RM))
    {
      stream_putc (s, (code == CAPABILITY_CODE_ORF ?
		   ORF_TYPE_PREFIX : ORF_TYPE_PREFIX_OLD));

      if (CHECK_FLAG (peer->af_flags[afi][safi], PEER_FLAG_ORF_PREFIX_SM)
	  && CHECK_FLAG (peer->af_flags[afi][safi], PEER_FLAG_ORF_PREFIX_RM))
	{
	  SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_SM_ADV);
	  SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_RM_ADV);
	  stream_putc (s, ORF_MODE_BOTH);
	}
      else if (CHECK_FLAG (peer->af_flags[afi][safi], PEER_FLAG_ORF_PREFIX_SM))
	{
	  SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_SM_ADV);
	  stream_putc (s, ORF_MODE_SEND);
	}
      else
	{
	  SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_RM_ADV);
	  stream_putc (s, ORF_MODE_RECEIVE);
	}
      number_of_orfs++;
    }

  /* Total Number of ORFs. */
  stream_putc_at (s, numberp, number_of_orfs);

  /* Total ORF Len. */
  orf_len = stream_get_endp (s) - orfp - 1;
  stream_putc_at (s, orfp, orf_len);

  /* Total Capability Len. */
  cap_len = stream_get_endp (s) - capp - 1;
  stream_putc_at (s, capp, cap_len);
}

/* Fill in capability open option to the packet. */
void
bgp_open_capability (struct stream *s, struct peer *peer)
{
  u_char len;
  unsigned long cp, capp, rcapp;
  afi_t afi;
  safi_t safi;
  as_t local_as;
  u_int32_t restart_time;
  u_char afi_safi_count = 0;
  struct utsname names;
  int adv_addpath_tx = 0;

  /* Remember current pointer for Opt Parm Len. */
  cp = stream_get_endp (s);

  /* Opt Parm Len. */
  stream_putc (s, 0);

  /* Do not send capability. */
  if (! CHECK_FLAG (peer->sflags, PEER_STATUS_CAPABILITY_OPEN) 
      || CHECK_FLAG (peer->flags, PEER_FLAG_DONT_CAPABILITY))
    return;

  /* IPv4 unicast. */
  if (peer->afc[AFI_IP][SAFI_UNICAST])
    {
      peer->afc_adv[AFI_IP][SAFI_UNICAST] = 1;
      stream_putc (s, BGP_OPEN_OPT_CAP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN + 2);
      stream_putc (s, CAPABILITY_CODE_MP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN);
      stream_putw (s, AFI_IP);
      stream_putc (s, 0);
      stream_putc (s, SAFI_UNICAST);
    }
  /* IPv4 multicast. */
  if (peer->afc[AFI_IP][SAFI_MULTICAST])
    {
      peer->afc_adv[AFI_IP][SAFI_MULTICAST] = 1;
      stream_putc (s, BGP_OPEN_OPT_CAP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN + 2);
      stream_putc (s, CAPABILITY_CODE_MP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN);
      stream_putw (s, AFI_IP);
      stream_putc (s, 0);
      stream_putc (s, SAFI_MULTICAST);
    }
  /* IPv4 VPN */
  if (peer->afc[AFI_IP][SAFI_MPLS_VPN])
    {
      peer->afc_adv[AFI_IP][SAFI_MPLS_VPN] = 1;
      stream_putc (s, BGP_OPEN_OPT_CAP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN + 2);
      stream_putc (s, CAPABILITY_CODE_MP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN);
      stream_putw (s, AFI_IP);
      stream_putc (s, 0);
      stream_putc (s, SAFI_MPLS_LABELED_VPN);
    }
#ifdef HAVE_IPV6
  /* Currently supporting RFC-5549 for Link-Local peering only */
  if (CHECK_FLAG (peer->flags, PEER_FLAG_CAPABILITY_ENHE) &&
      peer->su.sa.sa_family == AF_INET6 &&
      IN6_IS_ADDR_LINKLOCAL(&peer->su.sin6.sin6_addr))
    {
      /* RFC 5549 Extended Next Hop Encoding */
      SET_FLAG (peer->cap, PEER_CAP_ENHE_ADV);
      stream_putc (s, BGP_OPEN_OPT_CAP);
      stream_putc (s, CAPABILITY_CODE_ENHE_LEN + 2);
      stream_putc (s, CAPABILITY_CODE_ENHE);
      stream_putc (s, CAPABILITY_CODE_ENHE_LEN);
      /* Currently supporting for SAFI_UNICAST only */
      SET_FLAG (peer->af_cap[AFI_IP][SAFI_UNICAST], PEER_CAP_ENHE_AF_ADV);
      stream_putw (s, AFI_IP);
      stream_putw (s, SAFI_UNICAST);
      stream_putw (s, AFI_IP6);

      if (CHECK_FLAG (peer->af_cap[AFI_IP][SAFI_UNICAST], PEER_CAP_ENHE_AF_RCV))
        SET_FLAG (peer->af_cap[AFI_IP][SAFI_UNICAST], PEER_CAP_ENHE_AF_NEGO);
    }
  /* IPv6 unicast. */
  if (peer->afc[AFI_IP6][SAFI_UNICAST])
    {
      peer->afc_adv[AFI_IP6][SAFI_UNICAST] = 1;
      stream_putc (s, BGP_OPEN_OPT_CAP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN + 2);
      stream_putc (s, CAPABILITY_CODE_MP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN);
      stream_putw (s, AFI_IP6);
      stream_putc (s, 0);
      stream_putc (s, SAFI_UNICAST);
    }
  /* IPv6 multicast. */
  if (peer->afc[AFI_IP6][SAFI_MULTICAST])
    {
      peer->afc_adv[AFI_IP6][SAFI_MULTICAST] = 1;
      stream_putc (s, BGP_OPEN_OPT_CAP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN + 2);
      stream_putc (s, CAPABILITY_CODE_MP);
      stream_putc (s, CAPABILITY_CODE_MP_LEN);
      stream_putw (s, AFI_IP6);
      stream_putc (s, 0);
      stream_putc (s, SAFI_MULTICAST);
    }
#endif /* HAVE_IPV6 */

  /* Route refresh. */
  SET_FLAG (peer->cap, PEER_CAP_REFRESH_ADV);
  stream_putc (s, BGP_OPEN_OPT_CAP);
  stream_putc (s, CAPABILITY_CODE_REFRESH_LEN + 2);
  stream_putc (s, CAPABILITY_CODE_REFRESH_OLD);
  stream_putc (s, CAPABILITY_CODE_REFRESH_LEN);
  stream_putc (s, BGP_OPEN_OPT_CAP);
  stream_putc (s, CAPABILITY_CODE_REFRESH_LEN + 2);
  stream_putc (s, CAPABILITY_CODE_REFRESH);
  stream_putc (s, CAPABILITY_CODE_REFRESH_LEN);

  /* AS4 */
  SET_FLAG (peer->cap, PEER_CAP_AS4_ADV);
  stream_putc (s, BGP_OPEN_OPT_CAP);
  stream_putc (s, CAPABILITY_CODE_AS4_LEN + 2);
  stream_putc (s, CAPABILITY_CODE_AS4);
  stream_putc (s, CAPABILITY_CODE_AS4_LEN);
  if ( peer->change_local_as )
    local_as = peer->change_local_as;
  else
    local_as = peer->local_as;
  stream_putl (s, local_as );

  /* AddPath */
  for (afi = AFI_IP ; afi < AFI_MAX ; afi++)
    for (safi = SAFI_UNICAST ; safi < SAFI_MAX ; safi++)
      if (peer->afc[afi][safi])
        {
          afi_safi_count++;

          /* Only advertise addpath TX if a feature that will use it is
           * configured */
          if (CHECK_FLAG(peer->af_flags[afi][safi], PEER_FLAG_ADDPATH_TX_ALL_PATHS))
            adv_addpath_tx = 1;
        }

  SET_FLAG (peer->cap, PEER_CAP_ADDPATH_ADV);
  stream_putc (s, BGP_OPEN_OPT_CAP);
  stream_putc (s, (CAPABILITY_CODE_ADDPATH_LEN * afi_safi_count) + 2);
  stream_putc (s, CAPABILITY_CODE_ADDPATH);
  stream_putc (s, CAPABILITY_CODE_ADDPATH_LEN * afi_safi_count);

  for (afi = AFI_IP ; afi < AFI_MAX ; afi++)
    for (safi = SAFI_UNICAST ; safi < SAFI_MAX ; safi++)
      if (peer->afc[afi][safi])
        {
          stream_putw (s, afi);
          stream_putc (s, safi);

          if (adv_addpath_tx)
            {
              stream_putc (s, BGP_ADDPATH_RX|BGP_ADDPATH_TX);
              SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ADDPATH_AF_RX_ADV);
              SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ADDPATH_AF_TX_ADV);
            }
          else
            {
              stream_putc (s, BGP_ADDPATH_RX);
              SET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ADDPATH_AF_RX_ADV);
              UNSET_FLAG (peer->af_cap[afi][safi], PEER_CAP_ADDPATH_AF_TX_ADV);
            }
        }

  /* ORF capability. */
  for (afi = AFI_IP ; afi < AFI_MAX ; afi++)
    for (safi = SAFI_UNICAST ; safi < SAFI_MAX ; safi++)
      if (CHECK_FLAG (peer->af_flags[afi][safi], PEER_FLAG_ORF_PREFIX_SM)
	  || CHECK_FLAG (peer->af_flags[afi][safi], PEER_FLAG_ORF_PREFIX_RM))
	{
	  bgp_open_capability_orf (s, peer, afi, safi, CAPABILITY_CODE_ORF_OLD);
	  bgp_open_capability_orf (s, peer, afi, safi, CAPABILITY_CODE_ORF);
	}

  /* Dynamic capability. */
  if (CHECK_FLAG (peer->flags, PEER_FLAG_DYNAMIC_CAPABILITY))
    {
      SET_FLAG (peer->cap, PEER_CAP_DYNAMIC_ADV);
      stream_putc (s, BGP_OPEN_OPT_CAP);
      stream_putc (s, CAPABILITY_CODE_DYNAMIC_LEN + 2);
      stream_putc (s, CAPABILITY_CODE_DYNAMIC_OLD);
      stream_putc (s, CAPABILITY_CODE_DYNAMIC_LEN);
      stream_putc (s, BGP_OPEN_OPT_CAP);
      stream_putc (s, CAPABILITY_CODE_DYNAMIC_LEN + 2);
      stream_putc (s, CAPABILITY_CODE_DYNAMIC);
      stream_putc (s, CAPABILITY_CODE_DYNAMIC_LEN);
    }

  /* Hostname capability */
  uname(&names);
  if (names.nodename[0] != '\0')
    {
      SET_FLAG(peer->cap, PEER_CAP_HOSTNAME_ADV);
      stream_putc (s, BGP_OPEN_OPT_CAP);
      rcapp = stream_get_endp(s);	/* Ptr to length placeholder */
      stream_putc(s, 0);		/* dummy len for now */
      stream_putc (s, CAPABILITY_CODE_FQDN);
      capp = stream_get_endp(s);
      stream_putc(s, 0);		/* dummy len for now */
      len = strlen(names.nodename);
      if (len > BGP_MAX_HOSTNAME)
	len = BGP_MAX_HOSTNAME;

      stream_putc(s, len);
      stream_put(s, names.nodename, len);
#ifdef _GNU_SOURCE
      if ((names.domainname[0] != '\0') &&
	  (strcmp(names.domainname, "(none)") != 0))
	{
	  len = strlen(names.domainname);
	  if (len > BGP_MAX_HOSTNAME)
	    len = BGP_MAX_HOSTNAME;

	  stream_putc(s, len);
	  stream_put(s, names.domainname, len);
	}
	else
#endif
	{
	  stream_putc(s, 0);	/* 0 length */
	}

      /* Set the lengths straight */
      len = stream_get_endp(s) - rcapp - 1;
      stream_putc_at(s, rcapp, len);
      len = stream_get_endp(s) - capp - 1;
      stream_putc_at(s, capp, len);

      if (bgp_debug_neighbor_events(peer))
	zlog_debug("%s Sending hostname cap with hn = %s, dn = %s",
		   peer->host, names.nodename, names.domainname);
    }

  /* Sending base graceful-restart capability irrespective of the config */
  SET_FLAG (peer->cap, PEER_CAP_RESTART_ADV);
  stream_putc (s, BGP_OPEN_OPT_CAP);
  capp = stream_get_endp (s);           /* Set Capability Len Pointer */
  stream_putc (s, 0);                   /* Capability Length */
  stream_putc (s, CAPABILITY_CODE_RESTART);
  rcapp = stream_get_endp (s);          /* Set Restart Capability Len Pointer */
  stream_putc (s, 0);
  restart_time = peer->bgp->restart_time;
  if (peer->bgp->t_startup)
    {
      SET_FLAG (restart_time, RESTART_R_BIT);
      SET_FLAG (peer->cap, PEER_CAP_RESTART_BIT_ADV);
    }
  stream_putw (s, restart_time);

  /* Send address-family specific graceful-restart capability only when GR config
     is present */
  if (bgp_flag_check (peer->bgp, BGP_FLAG_GRACEFUL_RESTART))
    {
      for (afi = AFI_IP ; afi < AFI_MAX ; afi++)
        for (safi = SAFI_UNICAST ; safi < SAFI_MAX ; safi++)
          if (peer->afc[afi][safi])
            {
              stream_putw (s, afi);
              stream_putc (s, safi);
              stream_putc (s, 0); //Forwarding is not retained as of now.
            }
    }

  /* Total Graceful restart capability Len. */
  len = stream_get_endp (s) - rcapp - 1;
  stream_putc_at (s, rcapp, len);

  /* Total Capability Len. */
  len = stream_get_endp (s) - capp - 1;
  stream_putc_at (s, capp, len);

  /* Total Opt Parm Len. */
  len = stream_get_endp (s) - cp - 1;
  stream_putc_at (s, cp, len);
}