summaryrefslogtreecommitdiff
path: root/nest/rt-attr.c
blob: cec1d7cfdd72983ddd831bb0f09934beeb964705 (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
/*
 *	BIRD -- Route Attribute Cache
 *
 *	(c) 1998--2000 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

/**
 * DOC: Route attribute cache
 *
 * Each route entry carries a set of route attributes. Several of them
 * vary from route to route, but most attributes are usually common
 * for a large number of routes. To conserve memory, we've decided to
 * store only the varying ones directly in the &rte and hold the rest
 * in a special structure called &rta which is shared among all the
 * &rte's with these attributes.
 *
 * Each &rta contains all the static attributes of the route (i.e.,
 * those which are always present) as structure members and a list of
 * dynamic attributes represented by a linked list of &ea_list
 * structures, each of them consisting of an array of &eattr's containing
 * the individual attributes. An attribute can be specified more than once
 * in the &ea_list chain and in such case the first occurrence overrides
 * the others. This semantics is used especially when someone (for example
 * a filter) wishes to alter values of several dynamic attributes, but
 * it wants to preserve the original attribute lists maintained by
 * another module.
 *
 * Each &eattr contains an attribute identifier (split to protocol ID and
 * per-protocol attribute ID), protocol dependent flags, a type code (consisting
 * of several bit fields describing attribute characteristics) and either an
 * embedded 32-bit value or a pointer to a &adata structure holding attribute
 * contents.
 *
 * There exist two variants of &rta's -- cached and un-cached ones. Un-cached
 * &rta's can have arbitrarily complex structure of &ea_list's and they
 * can be modified by any module in the route processing chain. Cached
 * &rta's have their attribute lists normalized (that means at most one
 * &ea_list is present and its values are sorted in order to speed up
 * searching), they are stored in a hash table to make fast lookup possible
 * and they are provided with a use count to allow sharing.
 *
 * Routing tables always contain only cached &rta's.
 */

#include "nest/bird.h"
#include "nest/rt.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "nest/cli.h"
#include "lib/attrs.h"
#include "lib/alloca.h"
#include "lib/hash.h"
#include "lib/idm.h"
#include "lib/resource.h"
#include "lib/string.h"

#include <stddef.h>
#include <stdlib.h>

const adata null_adata;		/* adata of length 0 */

struct ea_class ea_gen_igp_metric = {
  .name = "igp_metric",
  .type = T_INT,
};

struct ea_class ea_gen_preference = {
  .name = "preference",
  .type = T_INT,
};

struct ea_class ea_gen_from = {
  .name = "from",
  .type = T_IP,
};

const char * const rta_src_names[RTS_MAX] = {
  [RTS_STATIC]		= "static",
  [RTS_INHERIT]		= "inherit",
  [RTS_DEVICE]		= "device",
  [RTS_STATIC_DEVICE]	= "static-device",
  [RTS_REDIRECT]	= "redirect",
  [RTS_RIP]		= "RIP",
  [RTS_OSPF]		= "OSPF",
  [RTS_OSPF_IA]		= "OSPF-IA",
  [RTS_OSPF_EXT1]	= "OSPF-E1",
  [RTS_OSPF_EXT2]	= "OSPF-E2",
  [RTS_BGP]		= "BGP",
  [RTS_PIPE]		= "pipe",
  [RTS_BABEL]		= "Babel",
  [RTS_RPKI]		= "RPKI",
};

static void
ea_gen_source_format(const eattr *a, byte *buf, uint size)
{
  if ((a->u.data >= RTS_MAX) || !rta_src_names[a->u.data])
    bsnprintf(buf, size, "unknown");
  else
    bsnprintf(buf, size, "%s", rta_src_names[a->u.data]);
}

struct ea_class ea_gen_source = {
  .name = "source",
  .type = T_ENUM_RTS,
  .readonly = 1,
  .format = ea_gen_source_format,
};

struct ea_class ea_gen_nexthop = {
  .name = "nexthop",
  .type = T_NEXTHOP_LIST,
};

/*
 * ea_set_hostentry() acquires hostentry from hostcache.
 * New hostentry has zero use count. Cached rta locks its
 * hostentry (increases its use count), uncached rta does not lock it.
 * Hostentry with zero use count is removed asynchronously
 * during host cache update, therefore it is safe to hold
 * such hostentry temporarily as long as you hold the table lock.
 *
 * There is no need to hold a lock for hostentry->dep table, because that table
 * contains routes responsible for that hostentry, and therefore is non-empty if
 * given hostentry has non-zero use count. If the hostentry has zero use count,
 * the entry is removed before dep is referenced.
 *
 * The protocol responsible for routes with recursive next hops should hold a
 * lock for a 'source' table governing that routes (argument tab),
 * because its routes reference hostentries related to the governing table.
 * When all such routes are
 * removed, rtas are immediately removed achieving zero uc. Then the 'source'
 * table lock could be immediately released, although hostentries may still
 * exist - they will be freed together with the 'source' table.
 */

  static void
ea_gen_hostentry_stored(const eattr *ea)
{
  struct hostentry_adata *had = (struct hostentry_adata *) ea->u.ptr;
  had->he->uc++;
}

static void
ea_gen_hostentry_freed(const eattr *ea)
{
  struct hostentry_adata *had = (struct hostentry_adata *) ea->u.ptr;
  had->he->uc--;
}

struct ea_class ea_gen_hostentry = {
  .name = "hostentry",
  .type = T_HOSTENTRY,
  .readonly = 1,
  .stored = ea_gen_hostentry_stored,
  .freed = ea_gen_hostentry_freed,
};

const char * rta_dest_names[RTD_MAX] = {
  [RTD_NONE]		= "",
  [RTD_UNICAST]		= "unicast",
  [RTD_BLACKHOLE]	= "blackhole",
  [RTD_UNREACHABLE]	= "unreachable",
  [RTD_PROHIBIT]	= "prohibited",
};

struct ea_class ea_gen_flowspec_valid = {
  .name = "flowspec_valid",
  .type = T_ENUM_FLOWSPEC_VALID,
  .readonly = 1,
};

const char * flowspec_valid_names[FLOWSPEC__MAX] = {
  [FLOWSPEC_UNKNOWN]	= "unknown",
  [FLOWSPEC_VALID]	= "",
  [FLOWSPEC_INVALID]	= "invalid",
};

pool *rta_pool;

static slab *rte_src_slab;

static struct idm src_ids;
#define SRC_ID_INIT_SIZE 4

/* rte source hash */

#define RSH_KEY(n)		n->proto, n->private_id
#define RSH_NEXT(n)		n->next
#define RSH_EQ(p1,n1,p2,n2)	p1 == p2 && n1 == n2
#define RSH_FN(p,n)		p->hash_key ^ u32_hash(n)

#define RSH_REHASH		rte_src_rehash
#define RSH_PARAMS		/2, *2, 1, 1, 8, 20
#define RSH_INIT_ORDER		6

static HASH(struct rte_src) src_hash;

static void
rte_src_init(void)
{
  rte_src_slab = sl_new(rta_pool, sizeof(struct rte_src));

  idm_init(&src_ids, rta_pool, SRC_ID_INIT_SIZE);

  HASH_INIT(src_hash, rta_pool, RSH_INIT_ORDER);
}


HASH_DEFINE_REHASH_FN(RSH, struct rte_src)

struct rte_src *
rt_find_source(struct proto *p, u32 id)
{
  return HASH_FIND(src_hash, RSH, p, id);
}

struct rte_src *
rt_get_source(struct proto *p, u32 id)
{
  struct rte_src *src = rt_find_source(p, id);

  if (src)
    return src;

  src = sl_allocz(rte_src_slab);
  src->proto = p;
  src->private_id = id;
  src->global_id = idm_alloc(&src_ids);
  src->uc = 0;

  HASH_INSERT2(src_hash, RSH, rta_pool, src);

  return src;
}

void
rt_prune_sources(void)
{
  HASH_WALK_FILTER(src_hash, next, src, sp)
  {
    if (src->uc == 0)
    {
      HASH_DO_REMOVE(src_hash, RSH, sp);
      idm_free(&src_ids, src->global_id);
      sl_free(src);
    }
  }
  HASH_WALK_FILTER_END;

  HASH_MAY_RESIZE_DOWN(src_hash, RSH, rta_pool);
}


/*
 *	Multipath Next Hop
 */

static int
nexthop_compare_node(const struct nexthop *x, const struct nexthop *y)
{
  int r;
  /* Should we also compare flags ? */

  r = ((int) y->weight) - ((int) x->weight);
  if (r)
    return r;

  r = ipa_compare(x->gw, y->gw);
  if (r)
    return r;

  r = ((int) y->labels) - ((int) x->labels);
  if (r)
    return r;

  for (int i = 0; i < y->labels; i++)
  {
    r = ((int) y->label[i]) - ((int) x->label[i]);
    if (r)
      return r;
  }

  return ((int) x->iface->index) - ((int) y->iface->index);
}

static int
nexthop_compare_qsort(const void *x, const void *y)
{
  return nexthop_compare_node( *(const struct nexthop **) x, *(const struct nexthop **) y );
}

/**
 * nexthop_merge - merge nexthop lists
 * @x: list 1
 * @y: list 2
 * @max: max number of nexthops
 * @lp: linpool for allocating nexthops
 *
 * The nexthop_merge() function takes two nexthop lists @x and @y and merges them,
 * eliminating possible duplicates. The input lists must be sorted and the
 * result is sorted too. The number of nexthops in result is limited by @max.
 * New nodes are allocated from linpool @lp.
 *
 * The arguments @rx and @ry specify whether corresponding input lists may be
 * consumed by the function (i.e. their nodes reused in the resulting list), in
 * that case the caller should not access these lists after that. To eliminate
 * issues with deallocation of these lists, the caller should use some form of
 * bulk deallocation (e.g. stack or linpool) to free these nodes when the
 * resulting list is no longer needed. When reusability is not set, the
 * corresponding lists are not modified nor linked from the resulting list.
 */
struct nexthop_adata *
nexthop_merge(struct nexthop_adata *xin, struct nexthop_adata *yin, int max, linpool *lp)
{
  uint outlen = ADATA_SIZE(xin->ad.length) + ADATA_SIZE(yin->ad.length);
  struct nexthop_adata *out = lp_alloc(lp, outlen);
  out->ad.length = outlen - sizeof (struct adata);

  struct nexthop *x = &xin->nh, *y = &yin->nh, *cur = &out->nh;
  int xvalid, yvalid;

  while (max--)
  {
    xvalid = NEXTHOP_VALID(x, xin);
    yvalid = NEXTHOP_VALID(y, yin);

    if (!xvalid && !yvalid)
      break;

    ASSUME(NEXTHOP_VALID(cur, out));

    int cmp = !xvalid ? 1 : !yvalid ? -1 : nexthop_compare_node(x, y);

    if (cmp < 0)
    {
      ASSUME(NEXTHOP_VALID(x, xin));
      memcpy(cur, x, nexthop_size(x));
      x = NEXTHOP_NEXT(x);
    }
    else if (cmp > 0)
    {
      ASSUME(NEXTHOP_VALID(y, yin));
      memcpy(cur, y, nexthop_size(y));
      y = NEXTHOP_NEXT(y);
    }
    else
    {
      ASSUME(NEXTHOP_VALID(x, xin));
      memcpy(cur, x, nexthop_size(x));
      x = NEXTHOP_NEXT(x);

      ASSUME(NEXTHOP_VALID(y, yin));
      y = NEXTHOP_NEXT(y);
    }
    cur = NEXTHOP_NEXT(cur);
  }

  out->ad.length = (void *) cur - (void *) out->ad.data;

  return out;
}

struct nexthop_adata *
nexthop_sort(struct nexthop_adata *nhad, linpool *lp)
{
  /* Count the nexthops */
  uint cnt = 0;
  NEXTHOP_WALK(nh, nhad)
    cnt++;

  if (cnt <= 1)
    return nhad;

  /* Get pointers to them */
  struct nexthop **sptr = tmp_alloc(cnt * sizeof(struct nexthop *));

  uint i = 0;
  NEXTHOP_WALK(nh, nhad)
    sptr[i++] = nh;

  /* Sort the pointers */
  qsort(sptr, cnt, sizeof(struct nexthop *), nexthop_compare_qsort);

  /* Allocate the output */
  struct nexthop_adata *out = (struct nexthop_adata *) lp_alloc_adata(lp, nhad->ad.length);
  struct nexthop *dest = &out->nh;

  /* Deduplicate nexthops while storing them */
  for (uint i = 0; i < cnt; i++)
  {
    if (i && !nexthop_compare_node(sptr[i], sptr[i-1]))
      continue;

    memcpy(dest, sptr[i], NEXTHOP_SIZE(sptr[i]));
    dest = NEXTHOP_NEXT(dest);
  }

  out->ad.length = (void *) dest - (void *) out->ad.data;
  return out;
}

int
nexthop_is_sorted(struct nexthop_adata *nhad)
{
  struct nexthop *prev = NULL;
  NEXTHOP_WALK(nh, nhad)
  {
    if (prev && (nexthop_compare_node(prev, nh) >= 0))
      return 0;

    prev = nh;
  }

  return 1;
}

/*
 *	Extended Attributes
 */

#define EA_CLASS_INITIAL_MAX	128
static struct ea_class **ea_class_global = NULL;
static uint ea_class_max;
static struct idm ea_class_idm;

/* Config parser lex register function */
void ea_lex_register(struct ea_class *def);
void ea_lex_unregister(struct ea_class *def);

static void
ea_class_free(struct ea_class *cl)
{
  /* No more ea class references. Unregister the attribute. */
  idm_free(&ea_class_idm, cl->id);
  ea_class_global[cl->id] = NULL;
  ea_lex_unregister(cl);
}

static void
ea_class_ref_free(resource *r)
{
  struct ea_class_ref *ref = SKIP_BACK(struct ea_class_ref, r, r);
  if (!--ref->class->uc)
    ea_class_free(ref->class);
}

static void
ea_class_ref_dump(resource *r)
{
  struct ea_class_ref *ref = SKIP_BACK(struct ea_class_ref, r, r);
  debug("name \"%s\", type=%d\n", ref->class->name, ref->class->type);
}

static struct resclass ea_class_ref_class = {
  .name = "Attribute class reference",
  .size = sizeof(struct ea_class_ref),
  .free = ea_class_ref_free,
  .dump = ea_class_ref_dump,
  .lookup = NULL,
  .memsize = NULL,
};

static void
ea_class_init(void)
{
  idm_init(&ea_class_idm, rta_pool, EA_CLASS_INITIAL_MAX);
  ea_class_global = mb_allocz(rta_pool,
      sizeof(*ea_class_global) * (ea_class_max = EA_CLASS_INITIAL_MAX));
}

static struct ea_class_ref *
ea_ref_class(pool *p, struct ea_class *def)
{
  def->uc++;
  struct ea_class_ref *ref = ralloc(p, &ea_class_ref_class);
  ref->class = def;
  return ref;
}

static struct ea_class_ref *
ea_register(pool *p, struct ea_class *def)
{
  def->id = idm_alloc(&ea_class_idm);

  ASSERT_DIE(ea_class_global);
  while (def->id >= ea_class_max)
    ea_class_global = mb_realloc(ea_class_global, sizeof(*ea_class_global) * (ea_class_max *= 2));

  ASSERT_DIE(def->id < ea_class_max);
  ea_class_global[def->id] = def;

  ea_lex_register(def);

  return ea_ref_class(p, def);
}

struct ea_class_ref *
ea_register_alloc(pool *p, struct ea_class cl)
{
  struct ea_class *clp = ea_class_find_by_name(cl.name);
  if (clp && clp->type == cl.type)
    return ea_ref_class(p, clp);

  uint namelen = strlen(cl.name) + 1;

  struct {
    struct ea_class cl;
    char name[0];
  } *cla = mb_alloc(rta_pool, sizeof(struct ea_class) + namelen);
  cla->cl = cl;
  memcpy(cla->name, cl.name, namelen);
  cla->cl.name = cla->name;

  return ea_register(p, &cla->cl);
}

void
ea_register_init(struct ea_class *clp)
{
  ASSERT_DIE(!ea_class_find_by_name(clp->name));
  ea_register(&root_pool, clp);
}

struct ea_class *
ea_class_find_by_id(uint id)
{
  ASSERT_DIE(id < ea_class_max);
  ASSERT_DIE(ea_class_global[id]);
  return ea_class_global[id];
}

static inline eattr *
ea__find(ea_list *e, unsigned id)
{
  eattr *a;
  int l, r, m;

  while (e)
    {
      if (e->flags & EALF_BISECT)
	{
	  l = 0;
	  r = e->count - 1;
	  while (l <= r)
	    {
	      m = (l+r) / 2;
	      a = &e->attrs[m];
	      if (a->id == id)
		return a;
	      else if (a->id < id)
		l = m+1;
	      else
		r = m-1;
	    }
	}
      else
	for(m=0; m<e->count; m++)
	  if (e->attrs[m].id == id)
	    return &e->attrs[m];
      e = e->next;
    }
  return NULL;
}

/**
 * ea_find - find an extended attribute
 * @e: attribute list to search in
 * @id: attribute ID to search for
 *
 * Given an extended attribute list, ea_find() searches for a first
 * occurrence of an attribute with specified ID, returning either a pointer
 * to its &eattr structure or %NULL if no such attribute exists.
 */
eattr *
ea_find_by_id(ea_list *e, unsigned id)
{
  eattr *a = ea__find(e, id & EA_CODE_MASK);

  if (a && a->undef && !(id & EA_ALLOW_UNDEF))
    return NULL;
  return a;
}

/**
 * ea_walk - walk through extended attributes
 * @s: walk state structure
 * @id: start of attribute ID interval
 * @max: length of attribute ID interval
 *
 * Given an extended attribute list, ea_walk() walks through the list looking
 * for first occurrences of attributes with ID in specified interval from @id to
 * (@id + @max - 1), returning pointers to found &eattr structures, storing its
 * walk state in @s for subsequent calls.
 *
 * The function ea_walk() is supposed to be called in a loop, with initially
 * zeroed walk state structure @s with filled the initial extended attribute
 * list, returning one found attribute in each call or %NULL when no other
 * attribute exists. The extended attribute list or the arguments should not be
 * modified between calls. The maximum value of @max is 128.
 */
eattr *
ea_walk(struct ea_walk_state *s, uint id, uint max)
{
  ea_list *e = s->eattrs;
  eattr *a = s->ea;
  eattr *a_max;

  max = id + max;

  if (a)
    goto step;

  for (; e; e = e->next)
  {
    if (e->flags & EALF_BISECT)
    {
      int l, r, m;

      l = 0;
      r = e->count - 1;
      while (l < r)
      {
	m = (l+r) / 2;
	if (e->attrs[m].id < id)
	  l = m + 1;
	else
	  r = m;
      }
      a = e->attrs + l;
    }
    else
      a = e->attrs;

  step:
    a_max = e->attrs + e->count;
    for (; a < a_max; a++)
      if ((a->id >= id) && (a->id < max))
      {
	int n = a->id - id;

	if (BIT32_TEST(s->visited, n))
	  continue;

	BIT32_SET(s->visited, n);

	if (a->undef)
	  continue;

	s->eattrs = e;
	s->ea = a;
	return a;
      }
      else if (e->flags & EALF_BISECT)
	break;
  }

  return NULL;
}

static inline void
ea_do_sort(ea_list *e)
{
  unsigned n = e->count;
  eattr *a = e->attrs;
  eattr *b = alloca(n * sizeof(eattr));
  unsigned s, ss;

  /* We need to use a stable sorting algorithm, hence mergesort */
  do
    {
      s = ss = 0;
      while (s < n)
	{
	  eattr *p, *q, *lo, *hi;
	  p = b;
	  ss = s;
	  *p++ = a[s++];
	  while (s < n && p[-1].id <= a[s].id)
	    *p++ = a[s++];
	  if (s < n)
	    {
	      q = p;
	      *p++ = a[s++];
	      while (s < n && p[-1].id <= a[s].id)
		*p++ = a[s++];
	      lo = b;
	      hi = q;
	      s = ss;
	      while (lo < q && hi < p)
		if (lo->id <= hi->id)
		  a[s++] = *lo++;
		else
		  a[s++] = *hi++;
	      while (lo < q)
		a[s++] = *lo++;
	      while (hi < p)
		a[s++] = *hi++;
	    }
	}
    }
  while (ss);
}

/**
 * In place discard duplicates and undefs in sorted ea_list. We use stable sort
 * for this reason.
 **/
static inline void
ea_do_prune(ea_list *e)
{
  eattr *s, *d, *l, *s0;
  int i = 0;

  s = d = e->attrs;	    /* Beginning of the list. @s is source, @d is destination. */
  l = e->attrs + e->count;  /* End of the list */

  /* Walk from begin to end. */
  while (s < l)
    {
      s0 = s++;
      /* Find a consecutive block of the same attribute */
      while (s < l && s->id == s[-1].id)
	s++;

      /* Now s0 is the most recent version, s[-1] the oldest one */
      /* Drop undefs unless this is a true overlay */
      if (s0->undef && (s[-1].undef || !e->next))
	continue;

      /* Copy the newest version to destination */
      *d = *s0;

      /* Preserve info whether it originated locally */
      d->originated = s[-1].originated;

      /* Not fresh any more, we prefer surstroemming */
      d->fresh = 0;

      /* Next destination */
      d++;
      i++;
    }

  e->count = i;
}

/**
 * ea_sort - sort an attribute list
 * @e: list to be sorted
 *
 * This function takes a &ea_list chain and sorts the attributes
 * within each of its entries.
 *
 * If an attribute occurs multiple times in a single &ea_list,
 * ea_sort() leaves only the first (the only significant) occurrence.
 */
static void
ea_sort(ea_list *e)
{
  if (!(e->flags & EALF_SORTED))
  {
    ea_do_sort(e);
    ea_do_prune(e);
    e->flags |= EALF_SORTED;
  }

  if (e->count > 5)
    e->flags |= EALF_BISECT;
}

/**
 * ea_scan - estimate attribute list size
 * @e: attribute list
 *
 * This function calculates an upper bound of the size of
 * a given &ea_list after merging with ea_merge().
 */
static unsigned
ea_scan(const ea_list *e, int overlay)
{
  unsigned cnt = 0;

  while (e)
    {
      cnt += e->count;
      e = e->next;
      if (e && overlay && ea_is_cached(e))
	break;
    }
  return sizeof(ea_list) + sizeof(eattr)*cnt;
}

/**
 * ea_merge - merge segments of an attribute list
 * @e: attribute list
 * @t: buffer to store the result to
 *
 * This function takes a possibly multi-segment attribute list
 * and merges all of its segments to one.
 *
 * The primary use of this function is for &ea_list normalization:
 * first call ea_scan() to determine how much memory will the result
 * take, then allocate a buffer (usually using alloca()), merge the
 * segments with ea_merge() and finally sort and prune the result
 * by calling ea_sort().
 */
static void
ea_merge(ea_list *e, ea_list *t, int overlay)
{
  eattr *d = t->attrs;

  t->flags = 0;
  t->count = 0;

  while (e)
    {
      memcpy(d, e->attrs, sizeof(eattr)*e->count);
      t->count += e->count;
      d += e->count;
      e = e->next;

      if (e && overlay && ea_is_cached(e))
	break;
    }

  t->next = e;
}

ea_list *
ea_normalize(ea_list *e, int overlay)
{
  ea_list *t = tmp_alloc(ea_scan(e, overlay));
  ea_merge(e, t, overlay);
  ea_sort(t);

  return t->count ? t : t->next;
}

/**
 * ea_same - compare two &ea_list's
 * @x: attribute list
 * @y: attribute list
 *
 * ea_same() compares two normalized attribute lists @x and @y and returns
 * 1 if they contain the same attributes, 0 otherwise.
 */
int
ea_same(ea_list *x, ea_list *y)
{
  int c;

  if (!x || !y)
    return x == y;
  if (x->next != y->next)
    return 0;
  if (x->count != y->count)
    return 0;
  for(c=0; c<x->count; c++)
    {
      eattr *a = &x->attrs[c];
      eattr *b = &y->attrs[c];

      if (a->id != b->id ||
	  a->flags != b->flags ||
	  a->type != b->type ||
	  a->originated != b->originated ||
	  a->fresh != b->fresh ||
	  a->undef != b->undef ||
	  ((a->type & EAF_EMBEDDED) ? a->u.data != b->u.data : !adata_same(a->u.ptr, b->u.ptr)))
	return 0;
    }
  return 1;
}

uint
ea_list_size(ea_list *o)
{
  unsigned i, elen;

  ASSERT_DIE(o);
  elen = BIRD_CPU_ALIGN(sizeof(ea_list) + sizeof(eattr) * o->count);

  for(i=0; i<o->count; i++)
    {
      eattr *a = &o->attrs[i];
      if (!a->undef && !(a->type & EAF_EMBEDDED))
	elen += ADATA_SIZE(a->u.ptr->length);
    }

  return elen;
}

void
ea_list_copy(ea_list *n, ea_list *o, uint elen)
{
  uint adpos = sizeof(ea_list) + sizeof(eattr) * o->count;
  memcpy(n, o, adpos);
  adpos = BIRD_CPU_ALIGN(adpos);

  for(uint i=0; i<o->count; i++)
    {
      eattr *a = &n->attrs[i];
      if (!a->undef && !(a->type & EAF_EMBEDDED))
	{
	  unsigned size = ADATA_SIZE(a->u.ptr->length);
	  ASSERT_DIE(adpos + size <= elen);

	  struct adata *d = ((void *) n) + adpos;
	  memcpy(d, a->u.ptr, size);
	  a->u.ptr = d;

	  adpos += size;
	}
    }

  ASSERT_DIE(adpos == elen);
}

static void
ea_list_ref(ea_list *l)
{
  for(uint i=0; i<l->count; i++)
    {
      eattr *a = &l->attrs[i];
      ASSERT_DIE(a->id < ea_class_max);

      if (a->undef)
	continue;

      struct ea_class *cl = ea_class_global[a->id];
      ASSERT_DIE(cl && cl->uc);

      CALL(cl->stored, a);
      cl->uc++;
    }

  if (l->next)
  {
    ASSERT_DIE(ea_is_cached(l->next));
    ea_clone(l->next);
  }
}

static void
ea_list_unref(ea_list *l)
{
  for(uint i=0; i<l->count; i++)
    {
      eattr *a = &l->attrs[i];
      ASSERT_DIE(a->id < ea_class_max);

      if (a->undef)
	continue;

      struct ea_class *cl = ea_class_global[a->id];
      ASSERT_DIE(cl && cl->uc);

      CALL(cl->freed, a);
      if (!--cl->uc)
	ea_class_free(cl);
    }

  if (l->next)
    ea_free(l->next);
}

void
ea_format_bitfield(const struct eattr *a, byte *buf, int bufsize, const char **names, int min, int max)
{
  byte *bound = buf + bufsize - 32;
  u32 data = a->u.data;
  int i;

  for (i = min; i < max; i++)
    if ((data & (1u << i)) && names[i])
    {
      if (buf > bound)
      {
	strcpy(buf, " ...");
	return;
      }

      buf += bsprintf(buf, " %s", names[i]);
      data &= ~(1u << i);
    }

  if (data)
    bsprintf(buf, " %08x", data);

  return;
}

static inline void
opaque_format(const struct adata *ad, byte *buf, uint size)
{
  byte *bound = buf + size - 10;
  uint i;

  for(i = 0; i < ad->length; i++)
    {
      if (buf > bound)
	{
	  strcpy(buf, " ...");
	  return;
	}
      if (i)
	*buf++ = ' ';

      buf += bsprintf(buf, "%02x", ad->data[i]);
    }

  *buf = 0;
  return;
}

static inline void
ea_show_int_set(struct cli *c, const struct adata *ad, int way, byte *pos, byte *buf, byte *end)
{
  int i = int_set_format(ad, way, 0, pos, end - pos);
  cli_printf(c, -1012, "\t%s", buf);
  while (i)
    {
      i = int_set_format(ad, way, i, buf, end - buf - 1);
      cli_printf(c, -1012, "\t\t%s", buf);
    }
}

static inline void
ea_show_ec_set(struct cli *c, const struct adata *ad, byte *pos, byte *buf, byte *end)
{
  int i = ec_set_format(ad, 0, pos, end - pos);
  cli_printf(c, -1012, "\t%s", buf);
  while (i)
    {
      i = ec_set_format(ad, i, buf, end - buf - 1);
      cli_printf(c, -1012, "\t\t%s", buf);
    }
}

static inline void
ea_show_lc_set(struct cli *c, const struct adata *ad, byte *pos, byte *buf, byte *end)
{
  int i = lc_set_format(ad, 0, pos, end - pos);
  cli_printf(c, -1012, "\t%s", buf);
  while (i)
    {
      i = lc_set_format(ad, i, buf, end - buf - 1);
      cli_printf(c, -1012, "\t\t%s", buf);
    }
}

/**
 * ea_show - print an &eattr to CLI
 * @c: destination CLI
 * @e: attribute to be printed
 *
 * This function takes an extended attribute represented by its &eattr
 * structure and prints it to the CLI according to the type information.
 *
 * If the protocol defining the attribute provides its own
 * get_attr() hook, it's consulted first.
 */
static void
ea_show(struct cli *c, const eattr *e)
{
  const struct adata *ad = (e->type & EAF_EMBEDDED) ? NULL : e->u.ptr;
  byte buf[CLI_MSG_SIZE];
  byte *pos = buf, *end = buf + sizeof(buf);

  ASSERT_DIE(e->id < ea_class_max);

  struct ea_class *cls = ea_class_global[e->id];
  ASSERT_DIE(cls);

  if (e->undef)
    return;
  else if (cls->format)
    cls->format(e, buf, end - buf);
  else
    switch (e->type)
      {
	case T_INT:
	  bsprintf(pos, "%u", e->u.data);
	  break;
	case T_OPAQUE:
	  opaque_format(ad, pos, end - pos);
	  break;
	case T_IP:
	  bsprintf(pos, "%I", *(ip_addr *) ad->data);
	  break;
	case T_QUAD:
	  bsprintf(pos, "%R", e->u.data);
	  break;
	case T_PATH:
	  as_path_format(ad, pos, end - pos);
	  break;
	case T_CLIST:
	  ea_show_int_set(c, ad, 1, pos, buf, end);
	  return;
	case T_ECLIST:
	  ea_show_ec_set(c, ad, pos, buf, end);
	  return;
	case T_LCLIST:
	  ea_show_lc_set(c, ad, pos, buf, end);
	  return;
	default:
	  bsprintf(pos, "<type %02x>", e->type);
      }

  cli_printf(c, -1012, "\t%s: %s", cls->name, buf);
}

static void
nexthop_dump(const struct adata *ad)
{
  struct nexthop_adata *nhad = (struct nexthop_adata *) ad;

  debug(":");

  NEXTHOP_WALK(nh, nhad)
    {
      if (ipa_nonzero(nh->gw)) debug(" ->%I", nh->gw);
      if (nh->labels) debug(" L %d", nh->label[0]);
      for (int i=1; i<nh->labels; i++)
	debug("/%d", nh->label[i]);
      debug(" [%s]", nh->iface ? nh->iface->name : "???");
    }
}

/**
 * ea_dump - dump an extended attribute
 * @e: attribute to be dumped
 *
 * ea_dump() dumps contents of the extended attribute given to
 * the debug output.
 */
void
ea_dump(ea_list *e)
{
  int i;

  if (!e)
    {
      debug("NONE");
      return;
    }
  while (e)
    {
      debug("[%c%c%c] uc=%d h=%08x",
	    (e->flags & EALF_SORTED) ? 'S' : 's',
	    (e->flags & EALF_BISECT) ? 'B' : 'b',
	    (e->flags & EALF_CACHED) ? 'C' : 'c',
	    e->uc, e->hash_key);
      for(i=0; i<e->count; i++)
	{
	  eattr *a = &e->attrs[i];
	  debug(" %04x.%02x", a->id, a->flags);
	  debug("=%c",
	      "?iO?IRP???S??pE?"
	      "??L???N?????????"
	      "?o???r??????????" [a->type]);
	  if (a->originated)
	    debug("o");
	  if (a->type & EAF_EMBEDDED)
	    debug(":%08x", a->u.data);
	  else if (a->id == ea_gen_nexthop.id)
	    nexthop_dump(a->u.ptr);
	  else
	    {
	      int j, len = a->u.ptr->length;
	      debug("[%d]:", len);
	      for(j=0; j<len; j++)
		debug("%02x", a->u.ptr->data[j]);
	    }
	}
      if (e = e->next)
	debug(" | ");
    }
}

/**
 * ea_hash - calculate an &ea_list hash key
 * @e: attribute list
 *
 * ea_hash() takes an extended attribute list and calculated a hopefully
 * uniformly distributed hash value from its contents.
 */
inline uint
ea_hash(ea_list *e)
{
  const u64 mul = 0x68576150f3d6847;
  u64 h = 0xafcef24eda8b29;
  int i;

  if (e)			/* Assuming chain of length 1 */
    {
      h ^= mem_hash(&e->next, sizeof(e->next));
      for(i=0; i<e->count; i++)
	{
	  struct eattr *a = &e->attrs[i];
	  h ^= a->id; h *= mul;
	  if (a->undef)
	    continue;
	  if (a->type & EAF_EMBEDDED)
	    h ^= a->u.data;
	  else
	    {
	      const struct adata *d = a->u.ptr;
	      h ^= mem_hash(d->data, d->length);
	    }
	  h *= mul;
	}
    }
  return (h >> 32) ^ (h & 0xffffffff);
}

/**
 * ea_append - concatenate &ea_list's
 * @to: destination list (can be %NULL)
 * @what: list to be appended (can be %NULL)
 *
 * This function appends the &ea_list @what at the end of
 * &ea_list @to and returns a pointer to the resulting list.
 */
ea_list *
ea_append(ea_list *to, ea_list *what)
{
  ea_list *res;

  if (!to)
    return what;
  res = to;
  while (to->next)
    to = to->next;
  to->next = what;
  return res;
}

/*
 *	rta's
 */

static uint rta_cache_count;
static uint rta_cache_size = 32;
static uint rta_cache_limit;
static uint rta_cache_mask;
static ea_list **rta_hash_table;

static void
rta_alloc_hash(void)
{
  rta_hash_table = mb_allocz(rta_pool, sizeof(ea_list *) * rta_cache_size);
  if (rta_cache_size < 32768)
    rta_cache_limit = rta_cache_size * 2;
  else
    rta_cache_limit = ~0;
  rta_cache_mask = rta_cache_size - 1;
}

static inline void
rta_insert(ea_list *r)
{
  uint h = r->hash_key & rta_cache_mask;
  r->next_hash = rta_hash_table[h];
  if (r->next_hash)
    r->next_hash->pprev_hash = &r->next_hash;
  r->pprev_hash = &rta_hash_table[h];
  rta_hash_table[h] = r;
}

static void
rta_rehash(void)
{
  uint ohs = rta_cache_size;
  uint h;
  ea_list *r, *n;
  ea_list **oht = rta_hash_table;

  rta_cache_size = 2*rta_cache_size;
  DBG("Rehashing rta cache from %d to %d entries.\n", ohs, rta_cache_size);
  rta_alloc_hash();
  for(h=0; h<ohs; h++)
    for(r=oht[h]; r; r=n)
      {
	n = r->next_hash;
	rta_insert(r);
      }
  mb_free(oht);
}

/**
 * rta_lookup - look up a &rta in attribute cache
 * @o: a un-cached &rta
 *
 * rta_lookup() gets an un-cached &rta structure and returns its cached
 * counterpart. It starts with examining the attribute cache to see whether
 * there exists a matching entry. If such an entry exists, it's returned and
 * its use count is incremented, else a new entry is created with use count
 * set to 1.
 *
 * The extended attribute lists attached to the &rta are automatically
 * converted to the normalized form.
 */
ea_list *
ea_lookup(ea_list *o, int overlay)
{
  ea_list *r;
  uint h;

  ASSERT(!ea_is_cached(o));
  o = ea_normalize(o, overlay);
  h = ea_hash(o);

  for(r=rta_hash_table[h & rta_cache_mask]; r; r=r->next_hash)
    if (r->hash_key == h && ea_same(r, o))
      return ea_clone(r);

  uint elen = ea_list_size(o);
  r = mb_alloc(rta_pool, elen);
  ea_list_copy(r, o, elen);
  ea_list_ref(r);

  r->flags |= EALF_CACHED;
  r->hash_key = h;
  r->uc = 1;

  rta_insert(r);

  if (++rta_cache_count > rta_cache_limit)
    rta_rehash();

  return r;
}

void
ea__free(ea_list *a)
{
  ASSERT(rta_cache_count && ea_is_cached(a));
  rta_cache_count--;
  *a->pprev_hash = a->next_hash;
  if (a->next_hash)
    a->next_hash->pprev_hash = a->pprev_hash;

  ea_list_unref(a);
  mb_free(a);
}

/**
 * rta_dump_all - dump attribute cache
 *
 * This function dumps the whole contents of route attribute cache
 * to the debug output.
 */
void
ea_dump_all(void)
{
  debug("Route attribute cache (%d entries, rehash at %d):\n", rta_cache_count, rta_cache_limit);
  for (uint h=0; h < rta_cache_size; h++)
    for (ea_list *a = rta_hash_table[h]; a; a = a->next_hash)
      {
	debug("%p ", a);
	ea_dump(a);
	debug("\n");
      }
  debug("\n");
}

void
ea_show_list(struct cli *c, ea_list *eal)
{
  for( ; eal; eal=eal->next)
    for(int i=0; i<eal->count; i++)
      ea_show(c, &eal->attrs[i]);
}

/**
 * rta_init - initialize route attribute cache
 *
 * This function is called during initialization of the routing
 * table module to set up the internals of the attribute cache.
 */
void
rta_init(void)
{
  rta_pool = rp_new(&root_pool, "Attributes");

  rta_alloc_hash();
  rte_src_init();
  ea_class_init();

  ea_register_init(&ea_gen_preference);
  ea_register_init(&ea_gen_igp_metric);
  ea_register_init(&ea_gen_from);
  ea_register_init(&ea_gen_source);
  ea_register_init(&ea_gen_nexthop);
  ea_register_init(&ea_gen_hostentry);
  ea_register_init(&ea_gen_flowspec_valid);
}

/*
 *  Documentation for functions declared inline in route.h
 */
#if 0

/**
 * rta_clone - clone route attributes
 * @r: a &rta to be cloned
 *
 * rta_clone() takes a cached &rta and returns its identical cached
 * copy. Currently it works by just returning the original &rta with
 * its use count incremented.
 */
static inline rta *rta_clone(rta *r)
{ DUMMY; }

/**
 * rta_free - free route attributes
 * @r: a &rta to be freed
 *
 * If you stop using a &rta (for example when deleting a route which uses
 * it), you need to call rta_free() to notify the attribute cache the
 * attribute is no longer in use and can be freed if you were the last
 * user (which rta_free() tests by inspecting the use count).
 */
static inline void rta_free(rta *r)
{ DUMMY; }

#endif