aboutsummaryrefslogtreecommitdiffstats
path: root/src/vlib/buffer_funcs.h
blob: ce8d1ef9078f17106bf07159c26cc222fe0f092f (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
/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * buffer_funcs.h: VLIB buffer related functions/inlines
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef included_vlib_buffer_funcs_h
#define included_vlib_buffer_funcs_h

#include <vppinfra/hash.h>
#include <vppinfra/fifo.h>

/** \file
    vlib buffer access methods.
*/


/** \brief Translate buffer index into buffer pointer

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffer_index - (u32) buffer index
    @return - (vlib_buffer_t *) buffer pointer
*/
always_inline vlib_buffer_t *
vlib_get_buffer (vlib_main_t * vm, u32 buffer_index)
{
  vlib_buffer_main_t *bm = vm->buffer_main;
  uword offset = ((uword) buffer_index) << CLIB_LOG2_CACHE_LINE_BYTES;
  ASSERT (offset < bm->buffer_mem_size);

  return uword_to_pointer (bm->buffer_mem_start + offset, void *);
}

static_always_inline void
vlib_buffer_copy_indices (u32 * dst, u32 * src, u32 n_indices)
{
  clib_memcpy_fast (dst, src, n_indices * sizeof (u32));
}

STATIC_ASSERT_OFFSET_OF (vlib_buffer_t, template_end, 64);
static_always_inline void
vlib_buffer_copy_template (vlib_buffer_t * b, vlib_buffer_t * bt)
{
#if defined CLIB_HAVE_VEC512
  b->as_u8x64[0] = bt->as_u8x64[0];
#elif defined (CLIB_HAVE_VEC256)
  b->as_u8x32[0] = bt->as_u8x32[0];
  b->as_u8x32[1] = bt->as_u8x32[1];
#elif defined (CLIB_HAVE_VEC128)
  b->as_u8x16[0] = bt->as_u8x16[0];
  b->as_u8x16[1] = bt->as_u8x16[1];
  b->as_u8x16[2] = bt->as_u8x16[2];
  b->as_u8x16[3] = bt->as_u8x16[3];
#else
  clib_memcpy_fast (b, bt, 64);
#endif
}

always_inline u8
vlib_buffer_pool_get_default_for_numa (vlib_main_t * vm, u32 numa_node)
{
  ASSERT (numa_node < vm->buffer_main->n_numa_nodes);
  return numa_node;
}

/** \brief Translate array of buffer indices into buffer pointers with offset

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param bi - (u32 *) array of buffer indices
    @param b - (void **) array to store buffer pointers
    @param count - (uword) number of elements
    @param offset - (i32) offset applied to each pointer
*/
static_always_inline void
vlib_get_buffers_with_offset (vlib_main_t * vm, u32 * bi, void **b, int count,
			      i32 offset)
{
#if defined (CLIB_HAVE_VEC256) || defined (CLIB_HAVE_VEC128)
  uword buffer_mem_start = vm->buffer_main->buffer_mem_start;
#endif
#ifdef CLIB_HAVE_VEC256
  u64x4 off = u64x4_splat (buffer_mem_start + offset);
  /* if count is not const, compiler will not unroll while loop
     se we maintain two-in-parallel variant */
  while (count >= 8)
    {
      u64x4 b0 = u32x4_extend_to_u64x4 (u32x4_load_unaligned (bi));
      u64x4 b1 = u32x4_extend_to_u64x4 (u32x4_load_unaligned (bi + 4));
      /* shift and add to get vlib_buffer_t pointer */
      u64x4_store_unaligned ((b0 << CLIB_LOG2_CACHE_LINE_BYTES) + off, b);
      u64x4_store_unaligned ((b1 << CLIB_LOG2_CACHE_LINE_BYTES) + off, b + 4);
      b += 8;
      bi += 8;
      count -= 8;
    }
#endif
  while (count >= 4)
    {
#ifdef CLIB_HAVE_VEC256
      u64x4 b0 = u32x4_extend_to_u64x4 (u32x4_load_unaligned (bi));
      /* shift and add to get vlib_buffer_t pointer */
      u64x4_store_unaligned ((b0 << CLIB_LOG2_CACHE_LINE_BYTES) + off, b);
#elif defined (CLIB_HAVE_VEC128)
      u64x2 off = u64x2_splat (buffer_mem_start + offset);
      u32x4 bi4 = u32x4_load_unaligned (bi);
      u64x2 b0 = u32x4_extend_to_u64x2 ((u32x4) bi4);
#if defined (__aarch64__)
      u64x2 b1 = u32x4_extend_to_u64x2_high ((u32x4) bi4);
#else
      bi4 = u32x4_shuffle (bi4, 2, 3, 0, 1);
      u64x2 b1 = u32x4_extend_to_u64x2 ((u32x4) bi4);
#endif
      u64x2_store_unaligned ((b0 << CLIB_LOG2_CACHE_LINE_BYTES) + off, b);
      u64x2_store_unaligned ((b1 << CLIB_LOG2_CACHE_LINE_BYTES) + off, b + 2);
#else
      b[0] = ((u8 *) vlib_get_buffer (vm, bi[0])) + offset;
      b[1] = ((u8 *) vlib_get_buffer (vm, bi[1])) + offset;
      b[2] = ((u8 *) vlib_get_buffer (vm, bi[2])) + offset;
      b[3] = ((u8 *) vlib_get_buffer (vm, bi[3])) + offset;
#endif
      b += 4;
      bi += 4;
      count -= 4;
    }
  while (count)
    {
      b[0] = ((u8 *) vlib_get_buffer (vm, bi[0])) + offset;
      b += 1;
      bi += 1;
      count -= 1;
    }
}

/** \brief Translate array of buffer indices into buffer pointers

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param bi - (u32 *) array of buffer indices
    @param b - (vlib_buffer_t **) array to store buffer pointers
    @param count - (uword) number of elements
*/

static_always_inline void
vlib_get_buffers (vlib_main_t * vm, u32 * bi, vlib_buffer_t ** b, int count)
{
  vlib_get_buffers_with_offset (vm, bi, (void **) b, count, 0);
}

/** \brief Translate buffer pointer into buffer index

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param p - (void *) buffer pointer
    @return - (u32) buffer index
*/

always_inline u32
vlib_get_buffer_index (vlib_main_t * vm, void *p)
{
  vlib_buffer_main_t *bm = vm->buffer_main;
  uword offset = pointer_to_uword (p) - bm->buffer_mem_start;
  ASSERT (pointer_to_uword (p) >= bm->buffer_mem_start);
  ASSERT (offset < bm->buffer_mem_size);
  ASSERT ((offset % (1 << CLIB_LOG2_CACHE_LINE_BYTES)) == 0);
  return offset >> CLIB_LOG2_CACHE_LINE_BYTES;
}

/** \brief Translate array of buffer pointers into buffer indices with offset

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param b - (void **) array of buffer pointers
    @param bi - (u32 *) array to store buffer indices
    @param count - (uword) number of elements
    @param offset - (i32) offset applied to each pointer
*/
static_always_inline void
vlib_get_buffer_indices_with_offset (vlib_main_t * vm, void **b, u32 * bi,
				     uword count, i32 offset)
{
#ifdef CLIB_HAVE_VEC256
  u32x8 mask = { 0, 2, 4, 6, 1, 3, 5, 7 };
  u64x4 off4 = u64x4_splat (vm->buffer_main->buffer_mem_start - offset);

  while (count >= 8)
    {
      /* load 4 pointers into 256-bit register */
      u64x4 v0 = u64x4_load_unaligned (b);
      u64x4 v1 = u64x4_load_unaligned (b + 4);
      u32x8 v2, v3;

      v0 -= off4;
      v1 -= off4;

      v0 >>= CLIB_LOG2_CACHE_LINE_BYTES;
      v1 >>= CLIB_LOG2_CACHE_LINE_BYTES;

      /* permute 256-bit register so lower u32s of each buffer index are
       * placed into lower 128-bits */
      v2 = u32x8_permute ((u32x8) v0, mask);
      v3 = u32x8_permute ((u32x8) v1, mask);

      /* extract lower 128-bits and save them to the array of buffer indices */
      u32x4_store_unaligned (u32x8_extract_lo (v2), bi);
      u32x4_store_unaligned (u32x8_extract_lo (v3), bi + 4);
      bi += 8;
      b += 8;
      count -= 8;
    }
#endif
  while (count >= 4)
    {
      /* equivalent non-nector implementation */
      bi[0] = vlib_get_buffer_index (vm, ((u8 *) b[0]) + offset);
      bi[1] = vlib_get_buffer_index (vm, ((u8 *) b[1]) + offset);
      bi[2] = vlib_get_buffer_index (vm, ((u8 *) b[2]) + offset);
      bi[3] = vlib_get_buffer_index (vm, ((u8 *) b[3]) + offset);
      bi += 4;
      b += 4;
      count -= 4;
    }
  while (count)
    {
      bi[0] = vlib_get_buffer_index (vm, ((u8 *) b[0]) + offset);
      bi += 1;
      b += 1;
      count -= 1;
    }
}

/** \brief Translate array of buffer pointers into buffer indices

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param b - (vlib_buffer_t **) array of buffer pointers
    @param bi - (u32 *) array to store buffer indices
    @param count - (uword) number of elements
*/
static_always_inline void
vlib_get_buffer_indices (vlib_main_t * vm, vlib_buffer_t ** b, u32 * bi,
			 uword count)
{
  vlib_get_buffer_indices_with_offset (vm, (void **) b, bi, count, 0);
}

/** \brief Get next buffer in buffer linklist, or zero for end of list.

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param b - (void *) buffer pointer
    @return - (vlib_buffer_t *) next buffer, or NULL
*/
always_inline vlib_buffer_t *
vlib_get_next_buffer (vlib_main_t * vm, vlib_buffer_t * b)
{
  return (b->flags & VLIB_BUFFER_NEXT_PRESENT
	  ? vlib_get_buffer (vm, b->next_buffer) : 0);
}

uword vlib_buffer_length_in_chain_slow_path (vlib_main_t * vm,
					     vlib_buffer_t * b_first);

/** \brief Get length in bytes of the buffer chain

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param b - (void *) buffer pointer
    @return - (uword) length of buffer chain
*/
always_inline uword
vlib_buffer_length_in_chain (vlib_main_t * vm, vlib_buffer_t * b)
{
  uword len = b->current_length;

  if (PREDICT_TRUE ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0))
    return len;

  if (PREDICT_TRUE (b->flags & VLIB_BUFFER_TOTAL_LENGTH_VALID))
    return len + b->total_length_not_including_first_buffer;

  return vlib_buffer_length_in_chain_slow_path (vm, b);
}

/** \brief Get length in bytes of the buffer index buffer chain

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param bi - (u32) buffer index
    @return - (uword) length of buffer chain
*/
always_inline uword
vlib_buffer_index_length_in_chain (vlib_main_t * vm, u32 bi)
{
  vlib_buffer_t *b = vlib_get_buffer (vm, bi);
  return vlib_buffer_length_in_chain (vm, b);
}

/** \brief Copy buffer contents to memory

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffer_index - (u32) buffer index
    @param contents - (u8 *) memory, <strong>must be large enough</strong>
    @return - (uword) length of buffer chain
*/
always_inline uword
vlib_buffer_contents (vlib_main_t * vm, u32 buffer_index, u8 * contents)
{
  uword content_len = 0;
  uword l;
  vlib_buffer_t *b;

  while (1)
    {
      b = vlib_get_buffer (vm, buffer_index);
      l = b->current_length;
      clib_memcpy_fast (contents + content_len, b->data + b->current_data, l);
      content_len += l;
      if (!(b->flags & VLIB_BUFFER_NEXT_PRESENT))
	break;
      buffer_index = b->next_buffer;
    }

  return content_len;
}

always_inline uword
vlib_buffer_get_pa (vlib_main_t * vm, vlib_buffer_t * b)
{
  return vlib_physmem_get_pa (vm, b->data);
}

always_inline uword
vlib_buffer_get_current_pa (vlib_main_t * vm, vlib_buffer_t * b)
{
  return vlib_buffer_get_pa (vm, b) + b->current_data;
}

/** \brief Prefetch buffer metadata by buffer index
    The first 64 bytes of buffer contains most header information

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param bi - (u32) buffer index
    @param type - LOAD, STORE. In most cases, STORE is the right answer
*/
/* Prefetch buffer header given index. */
#define vlib_prefetch_buffer_with_index(vm,bi,type)	\
  do {							\
    vlib_buffer_t * _b = vlib_get_buffer (vm, bi);	\
    vlib_prefetch_buffer_header (_b, type);		\
  } while (0)

typedef enum
{
  /* Index is unknown. */
  VLIB_BUFFER_UNKNOWN,

  /* Index is known and free/allocated. */
  VLIB_BUFFER_KNOWN_FREE,
  VLIB_BUFFER_KNOWN_ALLOCATED,
} vlib_buffer_known_state_t;

void vlib_buffer_validate_alloc_free (vlib_main_t * vm, u32 * buffers,
				      uword n_buffers,
				      vlib_buffer_known_state_t
				      expected_state);

always_inline vlib_buffer_known_state_t
vlib_buffer_is_known (vlib_main_t * vm, u32 buffer_index)
{
  vlib_buffer_main_t *bm = vm->buffer_main;

  clib_spinlock_lock (&bm->buffer_known_hash_lockp);
  uword *p = hash_get (bm->buffer_known_hash, buffer_index);
  clib_spinlock_unlock (&bm->buffer_known_hash_lockp);
  return p ? p[0] : VLIB_BUFFER_UNKNOWN;
}

/* Validates sanity of a single buffer.
   Returns format'ed vector with error message if any. */
u8 *vlib_validate_buffer (vlib_main_t * vm, u32 buffer_index,
			  uword follow_chain);

static_always_inline vlib_buffer_pool_t *
vlib_get_buffer_pool (vlib_main_t * vm, u8 buffer_pool_index)
{
  vlib_buffer_main_t *bm = vm->buffer_main;
  return vec_elt_at_index (bm->buffer_pools, buffer_pool_index);
}

static_always_inline uword
vlib_buffer_pool_get (vlib_main_t * vm, u8 buffer_pool_index, u32 * buffers,
		      u32 n_buffers)
{
  vlib_buffer_pool_t *bp = vlib_get_buffer_pool (vm, buffer_pool_index);
  u32 len;

  ASSERT (bp->buffers);

  clib_spinlock_lock (&bp->lock);
  len = vec_len (bp->buffers);
  if (PREDICT_TRUE (n_buffers < len))
    {
      len -= n_buffers;
      vlib_buffer_copy_indices (buffers, bp->buffers + len, n_buffers);
      _vec_len (bp->buffers) = len;
      clib_spinlock_unlock (&bp->lock);
      return n_buffers;
    }
  else
    {
      vlib_buffer_copy_indices (buffers, bp->buffers, len);
      _vec_len (bp->buffers) = 0;
      clib_spinlock_unlock (&bp->lock);
      return len;
    }
}


/** \brief Allocate buffers from specific pool into supplied array

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index array
    @param n_buffers - (u32) number of buffers requested
    @return - (u32) number of buffers actually allocated, may be
    less than the number requested or zero
*/

always_inline u32
vlib_buffer_alloc_from_pool (vlib_main_t * vm, u32 * buffers, u32 n_buffers,
			     u8 buffer_pool_index)
{
  vlib_buffer_main_t *bm = vm->buffer_main;
  vlib_buffer_pool_t *bp;
  vlib_buffer_pool_thread_t *bpt;
  u32 *src, *dst, len, n_left;

  bp = vec_elt_at_index (bm->buffer_pools, buffer_pool_index);
  bpt = vec_elt_at_index (bp->threads, vm->thread_index);

  dst = buffers;
  n_left = n_buffers;
  len = vec_len (bpt->cached_buffers);

  /* per-thread cache contains enough buffers */
  if (len >= n_buffers)
    {
      src = bpt->cached_buffers + len - n_buffers;
      vlib_buffer_copy_indices (dst, src, n_buffers);
      _vec_len (bpt->cached_buffers) -= n_buffers;

      if (CLIB_DEBUG > 0)
	vlib_buffer_validate_alloc_free (vm, buffers, n_buffers,
					 VLIB_BUFFER_KNOWN_FREE);
      return n_buffers;
    }

  /* take everything available in the cache */
  if (len)
    {
      vlib_buffer_copy_indices (dst, bpt->cached_buffers, len);
      _vec_len (bpt->cached_buffers) = 0;
      dst += len;
      n_left -= len;
    }

  len = round_pow2 (n_left, 32);
  vec_validate_aligned (bpt->cached_buffers, len - 1, CLIB_CACHE_LINE_BYTES);
  len = vlib_buffer_pool_get (vm, buffer_pool_index, bpt->cached_buffers,
			      len);
  _vec_len (bpt->cached_buffers) = len;

  if (len)
    {
      u32 n_copy = clib_min (len, n_left);
      src = bpt->cached_buffers + len - n_copy;
      vlib_buffer_copy_indices (dst, src, n_copy);
      _vec_len (bpt->cached_buffers) -= n_copy;
      n_left -= n_copy;
    }

  n_buffers -= n_left;

  /* Verify that buffers are known free. */
  if (CLIB_DEBUG > 0)
    vlib_buffer_validate_alloc_free (vm, buffers, n_buffers,
				     VLIB_BUFFER_KNOWN_FREE);

  return n_buffers;
}

/** \brief Allocate buffers from specific numa node into supplied array

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index array
    @param n_buffers - (u32) number of buffers requested
    @param numa_node - (u32) numa node
    @return - (u32) number of buffers actually allocated, may be
    less than the number requested or zero
*/
always_inline u32
vlib_buffer_alloc_on_numa (vlib_main_t * vm, u32 * buffers, u32 n_buffers,
			   u32 numa_node)
{
  u8 index = vlib_buffer_pool_get_default_for_numa (vm, numa_node);
  return vlib_buffer_alloc_from_pool (vm, buffers, n_buffers, index);
}

/** \brief Allocate buffers into supplied array

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index array
    @param n_buffers - (u32) number of buffers requested
    @return - (u32) number of buffers actually allocated, may be
    less than the number requested or zero
*/

always_inline u32
vlib_buffer_alloc (vlib_main_t * vm, u32 * buffers, u32 n_buffers)
{
  return vlib_buffer_alloc_on_numa (vm, buffers, n_buffers, vm->numa_node);
}

/** \brief Allocate buffers into ring

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index ring
    @param start - (u32) first slot in the ring
    @param ring_size - (u32) ring size
    @param n_buffers - (u32) number of buffers requested
    @return - (u32) number of buffers actually allocated, may be
    less than the number requested or zero
*/
always_inline u32
vlib_buffer_alloc_to_ring (vlib_main_t * vm, u32 * ring, u32 start,
			   u32 ring_size, u32 n_buffers)
{
  u32 n_alloc;

  ASSERT (n_buffers <= ring_size);

  if (PREDICT_TRUE (start + n_buffers <= ring_size))
    return vlib_buffer_alloc (vm, ring + start, n_buffers);

  n_alloc = vlib_buffer_alloc (vm, ring + start, ring_size - start);

  if (PREDICT_TRUE (n_alloc == ring_size - start))
    n_alloc += vlib_buffer_alloc (vm, ring, n_buffers - n_alloc);

  return n_alloc;
}

/** \brief Allocate buffers into ring from specific buffer pool

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index ring
    @param start - (u32) first slot in the ring
    @param ring_size - (u32) ring size
    @param n_buffers - (u32) number of buffers requested
    @return - (u32) number of buffers actually allocated, may be
    less than the number requested or zero
*/
always_inline u32
vlib_buffer_alloc_to_ring_from_pool (vlib_main_t * vm, u32 * ring, u32 start,
				     u32 ring_size, u32 n_buffers,
				     u8 buffer_pool_index)
{
  u32 n_alloc;

  ASSERT (n_buffers <= ring_size);

  if (PREDICT_TRUE (start + n_buffers <= ring_size))
    return vlib_buffer_alloc_from_pool (vm, ring + start, n_buffers,
					buffer_pool_index);

  n_alloc = vlib_buffer_alloc_from_pool (vm, ring + start, ring_size - start,
					 buffer_pool_index);

  if (PREDICT_TRUE (n_alloc == ring_size - start))
    n_alloc += vlib_buffer_alloc_from_pool (vm, ring, n_buffers - n_alloc,
					    buffer_pool_index);

  return n_alloc;
}

static void
vlib_buffer_pool_put (vlib_main_t * vm, u8 buffer_pool_index,
		      u32 * buffers, u32 n_buffers)
{
  vlib_buffer_pool_t *bp = vlib_get_buffer_pool (vm, buffer_pool_index);
  vlib_buffer_pool_thread_t *bpt =
    vec_elt_at_index (bp->threads, vm->thread_index);

  vec_add_aligned (bpt->cached_buffers, buffers, n_buffers,
		   CLIB_CACHE_LINE_BYTES);

  if (vec_len (bpt->cached_buffers) > 4 * VLIB_FRAME_SIZE)
    {
      clib_spinlock_lock (&bp->lock);
      /* keep last stored buffers, as they are more likely hot in the cache */
      vec_add_aligned (bp->buffers, bpt->cached_buffers, VLIB_FRAME_SIZE,
		       CLIB_CACHE_LINE_BYTES);
      vec_delete (bpt->cached_buffers, VLIB_FRAME_SIZE, 0);
      bpt->n_alloc -= VLIB_FRAME_SIZE;
      clib_spinlock_unlock (&bp->lock);
    }
}

static_always_inline void
vlib_buffer_free_inline (vlib_main_t * vm, u32 * buffers, u32 n_buffers,
			 int maybe_next)
{
  const int queue_size = 128;
  vlib_buffer_pool_t *bp = 0;
  u8 buffer_pool_index = ~0;
  u32 n_queue = 0, queue[queue_size + 4];
  vlib_buffer_t bt = { };
#if defined(CLIB_HAVE_VEC128) && !__aarch64__
  vlib_buffer_t bpi_mask = {.buffer_pool_index = ~0 };
  vlib_buffer_t bpi_vec = {.buffer_pool_index = ~0 };
  vlib_buffer_t flags_refs_mask = {
    .flags = VLIB_BUFFER_NEXT_PRESENT,
    .ref_count = ~0
  };
#endif

  while (n_buffers)
    {
      vlib_buffer_t *b[8];
      u32 bi, sum = 0, flags, next;

      if (n_buffers < 12)
	goto one_by_one;

      vlib_get_buffers (vm, buffers, b, 4);
      vlib_get_buffers (vm, buffers + 8, b + 4, 4);

      vlib_prefetch_buffer_header (b[4], LOAD);
      vlib_prefetch_buffer_header (b[5], LOAD);
      vlib_prefetch_buffer_header (b[6], LOAD);
      vlib_prefetch_buffer_header (b[7], LOAD);

#if defined(CLIB_HAVE_VEC128) && !__aarch64__
      u8x16 p0, p1, p2, p3, r;
      p0 = u8x16_load_unaligned (b[0]);
      p1 = u8x16_load_unaligned (b[1]);
      p2 = u8x16_load_unaligned (b[2]);
      p3 = u8x16_load_unaligned (b[3]);

      r = p0 ^ bpi_vec.as_u8x16[0];
      r |= p1 ^ bpi_vec.as_u8x16[0];
      r |= p2 ^ bpi_vec.as_u8x16[0];
      r |= p3 ^ bpi_vec.as_u8x16[0];
      r &= bpi_mask.as_u8x16[0];
      r |= (p0 | p1 | p2 | p3) & flags_refs_mask.as_u8x16[0];

      sum = !u8x16_is_all_zero (r);
#else
      sum |= b[0]->flags;
      sum |= b[1]->flags;
      sum |= b[2]->flags;
      sum |= b[3]->flags;
      sum &= VLIB_BUFFER_NEXT_PRESENT;
      sum += b[0]->ref_count - 1;
      sum += b[1]->ref_count - 1;
      sum += b[2]->ref_count - 1;
      sum += b[3]->ref_count - 1;
      sum |= b[0]->buffer_pool_index ^ buffer_pool_index;
      sum |= b[1]->buffer_pool_index ^ buffer_pool_index;
      sum |= b[2]->buffer_pool_index ^ buffer_pool_index;
      sum |= b[3]->buffer_pool_index ^ buffer_pool_index;
#endif

      if (sum)
	goto one_by_one;

      vlib_buffer_copy_indices (queue + n_queue, buffers, 4);
      vlib_buffer_copy_template (b[0], &bt);
      vlib_buffer_copy_template (b[1], &bt);
      vlib_buffer_copy_template (b[2], &bt);
      vlib_buffer_copy_template (b[3], &bt);
      n_queue += 4;

      if (CLIB_DEBUG > 0)
	vlib_buffer_validate_alloc_free (vm, buffers, 4,
					 VLIB_BUFFER_KNOWN_ALLOCATED);

      VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b[0]);
      VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b[1]);
      VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b[2]);
      VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b[3]);

      if (n_queue >= queue_size)
	{
	  vlib_buffer_pool_put (vm, buffer_pool_index, queue, n_queue);
	  n_queue = 0;
	}
      buffers += 4;
      n_buffers -= 4;
      continue;

    one_by_one:
      bi = buffers[0];

    next_in_chain:
      b[0] = vlib_get_buffer (vm, bi);
      flags = b[0]->flags;
      next = b[0]->next_buffer;

      if (PREDICT_FALSE (buffer_pool_index != b[0]->buffer_pool_index))
	{
	  buffer_pool_index = b[0]->buffer_pool_index;
#if defined(CLIB_HAVE_VEC128) && !__aarch64__
	  bpi_vec.buffer_pool_index = buffer_pool_index;
#endif
	  bp = vlib_get_buffer_pool (vm, buffer_pool_index);
	  vlib_buffer_copy_template (&bt, &bp->buffer_template);

	  if (n_queue)
	    {
	      vlib_buffer_pool_put (vm, buffer_pool_index, queue, n_queue);
	      n_queue = 0;
	    }
	}

      ASSERT (pointer_to_uword (b[0]) >= bp->start &&
	      pointer_to_uword (b[0]) <
	      bp->start + bp->size - (bp->data_size + sizeof (*b[0])));

      VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b[0]);

      if (clib_atomic_sub_fetch (&b[0]->ref_count, 1) == 0)
	{
	  if (CLIB_DEBUG > 0)
	    vlib_buffer_validate_alloc_free (vm, &bi, 1,
					     VLIB_BUFFER_KNOWN_ALLOCATED);
	  vlib_buffer_copy_template (b[0], &bt);
	  queue[n_queue++] = bi;
	}

      if (n_queue == queue_size)
	{
	  vlib_buffer_pool_put (vm, buffer_pool_index, queue, queue_size);
	  n_queue = 0;
	}

      if (flags & VLIB_BUFFER_NEXT_PRESENT)
	{
	  bi = next;
	  goto next_in_chain;
	}

      buffers++;
      n_buffers--;
    }

  if (n_queue)
    vlib_buffer_pool_put (vm, buffer_pool_index, queue, n_queue);
}


/** \brief Free buffers
    Frees the entire buffer chain for each buffer

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index array
    @param n_buffers - (u32) number of buffers to free

*/
always_inline void
vlib_buffer_free (vlib_main_t * vm,
		  /* pointer to first buffer */
		  u32 * buffers,
		  /* number of buffers to free */
		  u32 n_buffers)
{
  vlib_buffer_free_inline (vm, buffers, n_buffers, /* maybe next */ 1);
}

/** \brief Free buffers, does not free the buffer chain for each buffer

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index array
    @param n_buffers - (u32) number of buffers to free

*/
always_inline void
vlib_buffer_free_no_next (vlib_main_t * vm,
			  /* pointer to first buffer */
			  u32 * buffers,
			  /* number of buffers to free */
			  u32 n_buffers)
{
  vlib_buffer_free_inline (vm, buffers, n_buffers, /* maybe next */ 0);
}

/** \brief Free one buffer
    Shorthand to free a single buffer chain.

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffer_index - (u32) buffer index to free
*/
always_inline void
vlib_buffer_free_one (vlib_main_t * vm, u32 buffer_index)
{
  vlib_buffer_free_inline (vm, &buffer_index, 1, /* maybe next */ 1);
}

/** \brief Free buffers from ring

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index ring
    @param start - (u32) first slot in the ring
    @param ring_size - (u32) ring size
    @param n_buffers - (u32) number of buffers
*/
always_inline void
vlib_buffer_free_from_ring (vlib_main_t * vm, u32 * ring, u32 start,
			    u32 ring_size, u32 n_buffers)
{
  ASSERT (n_buffers <= ring_size);

  if (PREDICT_TRUE (start + n_buffers <= ring_size))
    {
      vlib_buffer_free (vm, ring + start, n_buffers);
    }
  else
    {
      vlib_buffer_free (vm, ring + start, ring_size - start);
      vlib_buffer_free (vm, ring, n_buffers - (ring_size - start));
    }
}

/** \brief Free buffers from ring without freeing tail buffers

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param buffers - (u32 * ) buffer index ring
    @param start - (u32) first slot in the ring
    @param ring_size - (u32) ring size
    @param n_buffers - (u32) number of buffers
*/
always_inline void
vlib_buffer_free_from_ring_no_next (vlib_main_t * vm, u32 * ring, u32 start,
				    u32 ring_size, u32 n_buffers)
{
  ASSERT (n_buffers <= ring_size);

  if (PREDICT_TRUE (start + n_buffers <= ring_size))
    {
      vlib_buffer_free_no_next (vm, ring + start, n_buffers);
    }
  else
    {
      vlib_buffer_free_no_next (vm, ring + start, ring_size - start);
      vlib_buffer_free_no_next (vm, ring, n_buffers - (ring_size - start));
    }
}

/* Append given data to end of buffer, possibly allocating new buffers. */
int vlib_buffer_add_data (vlib_main_t * vm, u32 * buffer_index, void *data,
			  u32 n_data_bytes);

/* duplicate all buffers in chain */
always_inline vlib_buffer_t *
vlib_buffer_copy (vlib_main_t * vm, vlib_buffer_t * b)
{
  vlib_buffer_t *s, *d, *fd;
  uword n_alloc, n_buffers = 1;
  u32 flag_mask = VLIB_BUFFER_NEXT_PRESENT | VLIB_BUFFER_TOTAL_LENGTH_VALID;
  int i;

  s = b;
  while (s->flags & VLIB_BUFFER_NEXT_PRESENT)
    {
      n_buffers++;
      s = vlib_get_buffer (vm, s->next_buffer);
    }
  u32 new_buffers[n_buffers];

  n_alloc = vlib_buffer_alloc (vm, new_buffers, n_buffers);

  /* No guarantee that we'll get all the buffers we asked for */
  if (PREDICT_FALSE (n_alloc < n_buffers))
    {
      if (n_alloc > 0)
	vlib_buffer_free (vm, new_buffers, n_alloc);
      return 0;
    }

  /* 1st segment */
  s = b;
  fd = d = vlib_get_buffer (vm, new_buffers[0]);
  d->current_data = s->current_data;
  d->current_length = s->current_length;
  d->flags = s->flags & flag_mask;
  d->total_length_not_including_first_buffer =
    s->total_length_not_including_first_buffer;
  clib_memcpy_fast (d->opaque, s->opaque, sizeof (s->opaque));
  clib_memcpy_fast (d->opaque2, s->opaque2, sizeof (s->opaque2));
  clib_memcpy_fast (vlib_buffer_get_current (d),
		    vlib_buffer_get_current (s), s->current_length);

  /* next segments */
  for (i = 1; i < n_buffers; i++)
    {
      /* previous */
      d->next_buffer = new_buffers[i];
      /* current */
      s = vlib_get_buffer (vm, s->next_buffer);
      d = vlib_get_buffer (vm, new_buffers[i]);
      d->current_data = s->current_data;
      d->current_length = s->current_length;
      clib_memcpy_fast (vlib_buffer_get_current (d),
			vlib_buffer_get_current (s), s->current_length);
      d->flags = s->flags & flag_mask;
    }

  return fd;
}

/** \brief Create a maximum of 256 clones of buffer and store them
    in the supplied array

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param src_buffer - (u32) source buffer index
    @param buffers - (u32 * ) buffer index array
    @param n_buffers - (u16) number of buffer clones requested (<=256)
    @param head_end_offset - (u16) offset relative to current position
           where packet head ends
    @return - (u16) number of buffers actually cloned, may be
    less than the number requested or zero
*/
always_inline u16
vlib_buffer_clone_256 (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
		       u16 n_buffers, u16 head_end_offset)
{
  u16 i;
  vlib_buffer_t *s = vlib_get_buffer (vm, src_buffer);

  ASSERT (s->ref_count == 1);
  ASSERT (n_buffers);
  ASSERT (n_buffers <= 256);

  if (s->current_length <= head_end_offset + CLIB_CACHE_LINE_BYTES * 2)
    {
      buffers[0] = src_buffer;
      for (i = 1; i < n_buffers; i++)
	{
	  vlib_buffer_t *d;
	  d = vlib_buffer_copy (vm, s);
	  if (d == 0)
	    return i;
	  buffers[i] = vlib_get_buffer_index (vm, d);

	}
      return n_buffers;
    }

  if (PREDICT_FALSE (n_buffers == 1))
    {
      buffers[0] = src_buffer;
      return 1;
    }

  n_buffers = vlib_buffer_alloc_from_pool (vm, buffers, n_buffers,
					   s->buffer_pool_index);

  for (i = 0; i < n_buffers; i++)
    {
      vlib_buffer_t *d = vlib_get_buffer (vm, buffers[i]);
      d->current_data = s->current_data;
      d->current_length = head_end_offset;
      ASSERT (d->buffer_pool_index == s->buffer_pool_index);

      d->total_length_not_including_first_buffer = s->current_length -
	head_end_offset;
      if (PREDICT_FALSE (s->flags & VLIB_BUFFER_NEXT_PRESENT))
	{
	  d->total_length_not_including_first_buffer +=
	    s->total_length_not_including_first_buffer;
	}
      d->flags = s->flags | VLIB_BUFFER_NEXT_PRESENT;
      d->flags &= ~VLIB_BUFFER_EXT_HDR_VALID;
      clib_memcpy_fast (d->opaque, s->opaque, sizeof (s->opaque));
      clib_memcpy_fast (d->opaque2, s->opaque2, sizeof (s->opaque2));
      clib_memcpy_fast (vlib_buffer_get_current (d),
			vlib_buffer_get_current (s), head_end_offset);
      d->next_buffer = src_buffer;
    }
  vlib_buffer_advance (s, head_end_offset);
  s->ref_count = n_buffers;
  while (s->flags & VLIB_BUFFER_NEXT_PRESENT)
    {
      s = vlib_get_buffer (vm, s->next_buffer);
      s->ref_count = n_buffers;
    }

  return n_buffers;
}

/** \brief Create multiple clones of buffer and store them
    in the supplied array

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param src_buffer - (u32) source buffer index
    @param buffers - (u32 * ) buffer index array
    @param n_buffers - (u16) number of buffer clones requested (<=256)
    @param head_end_offset - (u16) offset relative to current position
           where packet head ends
    @return - (u16) number of buffers actually cloned, may be
    less than the number requested or zero
*/
always_inline u16
vlib_buffer_clone (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
		   u16 n_buffers, u16 head_end_offset)
{
  vlib_buffer_t *s = vlib_get_buffer (vm, src_buffer);
  u16 n_cloned = 0;

  while (n_buffers > 256)
    {
      vlib_buffer_t *copy;
      copy = vlib_buffer_copy (vm, s);
      n_cloned += vlib_buffer_clone_256 (vm,
					 vlib_get_buffer_index (vm, copy),
					 (buffers + n_cloned),
					 256, head_end_offset);
      n_buffers -= 256;
    }
  n_cloned += vlib_buffer_clone_256 (vm, src_buffer,
				     buffers + n_cloned,
				     n_buffers, head_end_offset);

  return n_cloned;
}

/** \brief Attach cloned tail to the buffer

    @param vm - (vlib_main_t *) vlib main data structure pointer
    @param head - (vlib_buffer_t *) head buffer
    @param tail - (Vlib buffer_t *) tail buffer to clone and attach to head
*/

always_inline void
vlib_buffer_attach_clone (vlib_main_t * vm, vlib_buffer_t * head,
			  vlib_buffer_t * tail)
{
  ASSERT ((head->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
  ASSERT (head->buffer_pool_index == tail->buffer_pool_index);

  head->flags |= VLIB_BUFFER_NEXT_PRESENT;
  head->flags &= ~VLIB_BUFFER_TOTAL_LENGTH_VALID;
  head->flags &= ~VLIB_BUFFER_EXT_HDR_VALID;
  head->flags |= (tail->flags & VLIB_BUFFER_TOTAL_LENGTH_VALID);
  head->next_buffer = vlib_get_buffer_index (vm, tail);
  head->total_length_not_including_first_buffer = tail->current_length +
    tail->total_length_not_including_first_buffer;

next_segment:
  clib_atomic_add_fetch (&tail->ref_count, 1);

  if (tail->flags & VLIB_BUFFER_NEXT_PRESENT)
    {
      tail = vlib_get_buffer (vm, tail->next_buffer);
      goto next_segment;
    }
}

/* Initializes the buffer as an empty packet with no chained buffers. */
always_inline void
vlib_buffer_chain_init (vlib_buffer_t * first)
{
  first->total_length_not_including_first_buffer = 0;
  first->current_length = 0;
  first->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
  first->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
}

/* The provided next_bi buffer index is appended to the end of the packet. */
always_inline vlib_buffer_t *
vlib_buffer_chain_buffer (vlib_main_t * vm, vlib_buffer_t * last, u32 next_bi)
{
  vlib_buffer_t *next_buffer = vlib_get_buffer (vm, next_bi);
  last->next_buffer = next_bi;
  last->flags |= VLIB_BUFFER_NEXT_PRESENT;
  next_buffer->current_length = 0;
  next_buffer->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
  return next_buffer;
}

/* Increases or decreases the packet length.
 * It does not allocate or deallocate new buffers.
 * Therefore, the added length must be compatible
 * with the last buffer. */
always_inline void
vlib_buffer_chain_increase_length (vlib_buffer_t * first,
				   vlib_buffer_t * last, i32 len)
{
  last->current_length += len;
  if (first != last)
    first->total_length_not_including_first_buffer += len;
}

/* Copy data to the end of the packet and increases its length.
 * It does not allocate new buffers.
 * Returns the number of copied bytes. */
always_inline u16
vlib_buffer_chain_append_data (vlib_main_t * vm,
			       vlib_buffer_t * first,
			       vlib_buffer_t * last, void *data, u16 data_len)
{
  u32 n_buffer_bytes = VLIB_BUFFER_DATA_SIZE;
  ASSERT (n_buffer_bytes >= last->current_length + last->current_data);
  u16 len = clib_min (data_len,
		      n_buffer_bytes - last->current_length -
		      last->current_data);
  clib_memcpy_fast (vlib_buffer_get_current (last) + last->current_length,
		    data, len);
  vlib_buffer_chain_increase_length (first, last, len);
  return len;
}

/* Copy data to the end of the packet and increases its length.
 * Allocates additional buffers from the free list if necessary.
 * Returns the number of copied bytes.
 * 'last' value is modified whenever new buffers are allocated and
 * chained and points to the last buffer in the chain. */
u16
vlib_buffer_chain_append_data_with_alloc (vlib_main_t * vm,
					  vlib_buffer_t * first,
					  vlib_buffer_t ** last, void *data,
					  u16 data_len);
void vlib_buffer_chain_validate (vlib_main_t * vm, vlib_buffer_t * first);

format_function_t format_vlib_buffer, format_vlib_buffer_and_data,
  format_vlib_buffer_contents;

typedef struct
{
  /* Vector of packet data. */
  u8 *packet_data;

  /* Number of buffers to allocate in each call to allocator. */
  u32 min_n_buffers_each_alloc;

  u8 *name;
} vlib_packet_template_t;

void vlib_packet_template_init (vlib_main_t * vm,
				vlib_packet_template_t * t,
				void *packet_data,
				uword n_packet_data_bytes,
				uword min_n_buffers_each_alloc,
				char *fmt, ...);

void *vlib_packet_template_get_packet (vlib_main_t * vm,
				       vlib_packet_template_t * t,
				       u32 * bi_result);

always_inline void
vlib_packet_template_free (vlib_main_t * vm, vlib_packet_template_t * t)
{
  vec_free (t->packet_data);
}

/**
 * @brief compress buffer chain in a way where the first buffer is at least
 * VLIB_BUFFER_CLONE_HEAD_SIZE long
 *
 * @param[in] vm - vlib_main
 * @param[in,out] first - first buffer in chain
 * @param[in,out] discard_vector - vector of buffer indexes which were removed
 * from the chain
 */
always_inline void
vlib_buffer_chain_compress (vlib_main_t * vm,
			    vlib_buffer_t * first, u32 ** discard_vector)
{
  if (first->current_length >= VLIB_BUFFER_CLONE_HEAD_SIZE ||
      !(first->flags & VLIB_BUFFER_NEXT_PRESENT))
    {
      /* this is already big enough or not a chain */
      return;
    }

  u32 want_first_size = clib_min (VLIB_BUFFER_CLONE_HEAD_SIZE,
				  VLIB_BUFFER_DATA_SIZE -
				  first->current_data);
  do
    {
      vlib_buffer_t *second = vlib_get_buffer (vm, first->next_buffer);
      u32 need = want_first_size - first->current_length;
      u32 amount_to_copy = clib_min (need, second->current_length);
      clib_memcpy_fast (((u8 *) vlib_buffer_get_current (first)) +
			first->current_length,
			vlib_buffer_get_current (second), amount_to_copy);
      first->current_length += amount_to_copy;
      second->current_data += amount_to_copy;
      second->current_length -= amount_to_copy;
      if (first->flags & VLIB_BUFFER_TOTAL_LENGTH_VALID)
	{
	  first->total_length_not_including_first_buffer -= amount_to_copy;
	}
      if (!second->current_length)
	{
	  vec_add1 (*discard_vector, first->next_buffer);
	  if (second->flags & VLIB_BUFFER_NEXT_PRESENT)
	    {
	      first->next_buffer = second->next_buffer;
	    }
	  else
	    {
	      first->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
	    }
	  second->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
	}
    }
  while ((first->current_length < want_first_size) &&
	 (first->flags & VLIB_BUFFER_NEXT_PRESENT));
}

/**
 * @brief linearize buffer chain - the first buffer is filled, if needed,
 * buffers are allocated and filled, returns free space in last buffer or
 * negative on failure
 *
 * @param[in] vm - vlib_main
 * @param[in,out] first - first buffer in chain
 */
always_inline int
vlib_buffer_chain_linearize (vlib_main_t * vm, vlib_buffer_t * first)
{
  vlib_buffer_t *b = first;
  u32 buf_len = VLIB_BUFFER_DATA_SIZE;
  // free buffer chain starting from the second buffer
  int free_count = (b->flags & VLIB_BUFFER_NEXT_PRESENT) != 0;
  u32 chain_to_free = b->next_buffer;

  u32 len = vlib_buffer_length_in_chain (vm, b);
  u32 free_len = buf_len - b->current_data - b->current_length;
  int alloc_len = clib_max (len - free_len, 0);	//use the free len in the first buffer
  int n_buffers = (alloc_len + buf_len - 1) / buf_len;
  u32 new_buffers[n_buffers];

  u32 n_alloc = vlib_buffer_alloc (vm, new_buffers, n_buffers);
  if (n_alloc != n_buffers)
    {
      vlib_buffer_free_no_next (vm, new_buffers, n_alloc);
      return -1;
    }

  vlib_buffer_t *s = b;
  while (s->flags & VLIB_BUFFER_NEXT_PRESENT)
    {
      s = vlib_get_buffer (vm, s->next_buffer);
      int d_free_len = buf_len - b->current_data - b->current_length;
      ASSERT (d_free_len >= 0);
      // chain buf and split write
      u32 copy_len = clib_min (d_free_len, s->current_length);
      u8 *d = vlib_buffer_put_uninit (b, copy_len);
      clib_memcpy (d, vlib_buffer_get_current (s), copy_len);
      int rest = s->current_length - copy_len;
      if (rest > 0)
	{
	  //prev buf is full
	  ASSERT (vlib_buffer_get_tail (b) == b->data + buf_len);
	  ASSERT (n_buffers > 0);
	  b = vlib_buffer_chain_buffer (vm, b, new_buffers[--n_buffers]);
	  //make full use of the new buffers
	  b->current_data = 0;
	  d = vlib_buffer_put_uninit (b, rest);
	  clib_memcpy (d, vlib_buffer_get_current (s) + copy_len, rest);
	}
    }
  vlib_buffer_free (vm, &chain_to_free, free_count);
  b->flags &= ~VLIB_BUFFER_TOTAL_LENGTH_VALID;
  if (b == first)		/* no buffers addeed */
    b->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
  ASSERT (len == vlib_buffer_length_in_chain (vm, first));
  ASSERT (n_buffers == 0);
  return buf_len - b->current_data - b->current_length;
}

#endif /* included_vlib_buffer_funcs_h */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */