aboutsummaryrefslogtreecommitdiffstats
path: root/src/vnet/unix/tapcli.c
blob: f39e2d7e75d899dc7982a717f37b6ee2be8da8c2 (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
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
/*
 *------------------------------------------------------------------
 * tapcli.c - dynamic tap interface hookup
 *
 * Copyright (c) 2009 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.
 *------------------------------------------------------------------
 */
/**
 * @file
 * @brief  dynamic tap interface hookup
 */

#include <fcntl.h>		/* for open */
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/uio.h>		/* for iovec */
#include <netinet/in.h>

#include <linux/if_arp.h>
#include <linux/if_tun.h>

#include <vlib/vlib.h>
#include <vlib/unix/unix.h>

#include <vnet/ip/ip.h>

#include <vnet/ethernet/ethernet.h>

#include <vnet/feature/feature.h>
#include <vnet/devices/devices.h>
#include <vnet/unix/tuntap.h>
#include <vnet/unix/tapcli.h>

static vnet_device_class_t tapcli_dev_class;
static vnet_hw_interface_class_t tapcli_interface_class;
static vlib_node_registration_t tapcli_rx_node;

static void tapcli_nopunt_frame (vlib_main_t * vm,
                                 vlib_node_runtime_t * node,
                                 vlib_frame_t * frame);
/**
 * @brief Struct for the tapcli interface
 */
typedef struct {
  u32 unix_fd;
  u32 unix_file_index;
  u32 provision_fd;
  /** For counters */
  u32 sw_if_index;
  u32 hw_if_index;
  u32 is_promisc;
  struct ifreq ifr;
  u32 per_interface_next_index;
  /** for delete */
  u8 active;
} tapcli_interface_t;

/**
 * @brief Struct for RX trace
 */
typedef struct {
  u16 sw_if_index;
} tapcli_rx_trace_t;

/**
 * @brief Function to format TAP CLI trace
 *
 * @param *s - u8 - formatting string
 * @param *va - va_list
 *
 * @return *s - u8 - formatted string
 *
 */
u8 * format_tapcli_rx_trace (u8 * s, va_list * va)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
  vnet_main_t * vnm = vnet_get_main();
  tapcli_rx_trace_t * t = va_arg (*va, tapcli_rx_trace_t *);
  s = format (s, "%U", format_vnet_sw_if_index_name,
                vnm, t->sw_if_index);
  return s;
}

/**
 * @brief TAPCLI main state struct
 */
typedef struct {
  /** Vector of iovecs for readv calls. */
  struct iovec * rd_iovecs;

  /** Vector of iovecs for writev calls. */
  struct iovec * wr_iovecs;

  /** Vector of VLIB rx buffers to use.  We allocate them in blocks
     of VLIB_FRAME_SIZE (256). */
  u32 * rx_buffers;

  /** tap device destination MAC address. Required, or Linux drops pkts */
  u8 ether_dst_mac[6];

  /** Interface MTU in bytes and # of default sized buffers. */
  u32 mtu_bytes, mtu_buffers;

  /** Vector of tap interfaces */
  tapcli_interface_t * tapcli_interfaces;

  /** Vector of deleted tap interfaces */
  u32 * tapcli_inactive_interfaces;

  /** Bitmap of tap interfaces with pending reads */
  uword * pending_read_bitmap;

  /** Hash table to find tapcli interface given hw_if_index */
  uword * tapcli_interface_index_by_sw_if_index;

  /** Hash table to find tapcli interface given unix fd */
  uword * tapcli_interface_index_by_unix_fd;

  /** renumbering table */
  u32 * show_dev_instance_by_real_dev_instance;

  /** 1 => disable CLI */
  int is_disabled;

  /** convenience - vlib_main_t */
  vlib_main_t * vlib_main;
  /** convenience - vnet_main_t */
  vnet_main_t * vnet_main;
  /** convenience - unix_main_t */
  unix_main_t * unix_main;
} tapcli_main_t;

static tapcli_main_t tapcli_main;

/**
 * @brief tapcli TX node function
 * @node tap-cli-tx
 *
 * Output node, writes the buffers comprising the incoming frame
 * to the tun/tap device, aka hands them to the Linux kernel stack.
 *
 * @param *vm - vlib_main_t
 * @param *node - vlib_node_runtime_t
 * @param *frame - vlib_frame_t
 *
 * @return n_packets - uword
 *
 */
static uword
tapcli_tx (vlib_main_t * vm,
	   vlib_node_runtime_t * node,
	   vlib_frame_t * frame)
{
  u32 * buffers = vlib_frame_args (frame);
  uword n_packets = frame->n_vectors;
  tapcli_main_t * tm = &tapcli_main;
  tapcli_interface_t * ti;
  int i;

  for (i = 0; i < n_packets; i++)
    {
      struct iovec * iov;
      vlib_buffer_t * b;
      uword l;
      vnet_hw_interface_t * hw;
      uword * p;
      u32 tx_sw_if_index;

      b = vlib_get_buffer (vm, buffers[i]);

      tx_sw_if_index = vnet_buffer(b)->sw_if_index[VLIB_TX];
      if (tx_sw_if_index == (u32)~0)
        tx_sw_if_index = vnet_buffer(b)->sw_if_index[VLIB_RX];
        
      ASSERT(tx_sw_if_index != (u32)~0);

      /* Use the sup intfc to finesse vlan subifs */
      hw = vnet_get_sup_hw_interface (tm->vnet_main, tx_sw_if_index);
      tx_sw_if_index = hw->sw_if_index;

      p = hash_get (tm->tapcli_interface_index_by_sw_if_index, 
                    tx_sw_if_index);
      if (p == 0)
        {
          clib_warning ("sw_if_index %d unknown", tx_sw_if_index);
          /* $$$ leak, but this should never happen... */
          continue;
        }
      else
        ti = vec_elt_at_index (tm->tapcli_interfaces, p[0]);

      /* Re-set iovecs if present. */
      if (tm->wr_iovecs)
	_vec_len (tm->wr_iovecs) = 0;

      /* VLIB buffer chain -> Unix iovec(s). */
      vec_add2 (tm->wr_iovecs, iov, 1);
      iov->iov_base = b->data + b->current_data;
      iov->iov_len = l = b->current_length;

      if (PREDICT_FALSE (b->flags & VLIB_BUFFER_NEXT_PRESENT))
	{
	  do {
	    b = vlib_get_buffer (vm, b->next_buffer);

	    vec_add2 (tm->wr_iovecs, iov, 1);

	    iov->iov_base = b->data + b->current_data;
	    iov->iov_len = b->current_length;
	    l += b->current_length;
	  } while (b->flags & VLIB_BUFFER_NEXT_PRESENT);
	}

      if (writev (ti->unix_fd, tm->wr_iovecs, vec_len (tm->wr_iovecs)) < l)
	clib_unix_warning ("writev");
    }

  vlib_buffer_free(vm, vlib_frame_vector_args(frame), frame->n_vectors);

  return n_packets;
}

VLIB_REGISTER_NODE (tapcli_tx_node,static) = {
  .function = tapcli_tx,
  .name = "tapcli-tx",
  .type = VLIB_NODE_TYPE_INTERNAL,
  .vector_size = 4,
};

/**
 * @brief Dispatch tapcli RX node function for node tap_cli_rx
 *
 *
 * @param *vm - vlib_main_t
 * @param *node - vlib_node_runtime_t
 * @param *ti - tapcli_interface_t
 *
 * @return n_packets - uword
 *
 */
static uword tapcli_rx_iface(vlib_main_t * vm,
                            vlib_node_runtime_t * node,
                            tapcli_interface_t * ti)
{
  tapcli_main_t * tm = &tapcli_main;
  const uword buffer_size = VLIB_BUFFER_DATA_SIZE;
  u32 n_trace = vlib_get_trace_count (vm, node);
  u8 set_trace = 0;

  vnet_main_t *vnm;
  vnet_sw_interface_t * si;
  u8 admin_down;
  u32 next = node->cached_next_index;
  u32 n_left_to_next, next_index;
  u32 *to_next;

  vnm = vnet_get_main();
  si = vnet_get_sw_interface (vnm, ti->sw_if_index);
  admin_down = !(si->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP);

  vlib_get_next_frame(vm, node, next, to_next, n_left_to_next);

  while (n_left_to_next) { // Fill at most one vector
    vlib_buffer_t *b_first, *b, *prev;
    u32 bi_first, bi;
    word n_bytes_in_packet;
    int j, n_bytes_left;

    if (PREDICT_FALSE(vec_len(tm->rx_buffers) < tm->mtu_buffers)) {
      uword len = vec_len(tm->rx_buffers);
      _vec_len(tm->rx_buffers) +=
          vlib_buffer_alloc_from_free_list(vm, &tm->rx_buffers[len],
                            VLIB_FRAME_SIZE - len, VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
      if (PREDICT_FALSE(vec_len(tm->rx_buffers) < tm->mtu_buffers)) {
          vlib_node_increment_counter(vm, tapcli_rx_node.index,
                                      TAPCLI_ERROR_BUFFER_ALLOC,
                                      tm->mtu_buffers - vec_len(tm->rx_buffers));
        break;
      }
    }

    uword i_rx = vec_len (tm->rx_buffers) - 1;

    /* Allocate RX buffers from end of rx_buffers.
           Turn them into iovecs to pass to readv. */
    vec_validate (tm->rd_iovecs, tm->mtu_buffers - 1);
    for (j = 0; j < tm->mtu_buffers; j++) {
      b = vlib_get_buffer (vm, tm->rx_buffers[i_rx - j]);
      tm->rd_iovecs[j].iov_base = b->data;
      tm->rd_iovecs[j].iov_len = buffer_size;
    }

    n_bytes_left = readv (ti->unix_fd, tm->rd_iovecs, tm->mtu_buffers);
    n_bytes_in_packet = n_bytes_left;
    if (n_bytes_left <= 0) {
      if (errno != EAGAIN) {
        vlib_node_increment_counter(vm, tapcli_rx_node.index,
                                    TAPCLI_ERROR_READ, 1);
      }
      break;
    }

    bi_first = tm->rx_buffers[i_rx];
    b = b_first = vlib_get_buffer (vm, tm->rx_buffers[i_rx]);
    prev = NULL;

    while (1) {
      b->current_length = n_bytes_left < buffer_size ? n_bytes_left : buffer_size;
      n_bytes_left -= buffer_size;

      if (prev) {
        prev->next_buffer = bi;
        prev->flags |= VLIB_BUFFER_NEXT_PRESENT;
      }
      prev = b;

      /* last segment */
      if (n_bytes_left <= 0)
        break;

      i_rx--;
      bi = tm->rx_buffers[i_rx];
      b = vlib_get_buffer (vm, bi);
    }

    _vec_len (tm->rx_buffers) = i_rx;

    b_first->total_length_not_including_first_buffer =
        (n_bytes_in_packet > buffer_size) ? n_bytes_in_packet - buffer_size : 0;
    b_first->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;

    VLIB_BUFFER_TRACE_TRAJECTORY_INIT(b_first);

    vnet_buffer (b_first)->sw_if_index[VLIB_RX] = ti->sw_if_index;
    vnet_buffer (b_first)->sw_if_index[VLIB_TX] = (u32)~0;

    b_first->error = node->errors[TAPCLI_ERROR_NONE];
    next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
    next_index = (ti->per_interface_next_index != ~0) ?
        ti->per_interface_next_index : next_index;
    next_index = admin_down ? VNET_DEVICE_INPUT_NEXT_DROP : next_index;

    to_next[0] = bi_first;
    to_next++;
    n_left_to_next--;

    vnet_feature_start_device_input_x1 (ti->sw_if_index, &next_index, b_first);

    vlib_validate_buffer_enqueue_x1 (vm, node, next,
                                     to_next, n_left_to_next,
                                     bi_first, next_index);

    /* Interface counters for tapcli interface. */
    if (PREDICT_TRUE(!admin_down)) {
      vlib_increment_combined_counter (
          vnet_main.interface_main.combined_sw_if_counters
          + VNET_INTERFACE_COUNTER_RX,
          vlib_get_thread_index(), ti->sw_if_index,
          1, n_bytes_in_packet);

      if (PREDICT_FALSE(n_trace > 0)) {
        vlib_trace_buffer (vm, node, next_index,
                           b_first, /* follow_chain */ 1);
        n_trace--;
        set_trace = 1;
        tapcli_rx_trace_t *t0 = vlib_add_trace (vm, node, b_first, sizeof (*t0));
        t0->sw_if_index = si->sw_if_index;
      }
    }
  }
  vlib_put_next_frame (vm, node, next, n_left_to_next);
  if (set_trace)
    vlib_set_trace_count (vm, node, n_trace);
  return VLIB_FRAME_SIZE - n_left_to_next;
}

/**
 * @brief tapcli RX node function
 * @node tap-cli-rx
 *
 * Input node from the Kernel tun/tap device
 *
 * @param *vm - vlib_main_t
 * @param *node - vlib_node_runtime_t
 * @param *frame - vlib_frame_t
 *
 * @return n_packets - uword
 *
 */
static uword
tapcli_rx (vlib_main_t * vm,
	   vlib_node_runtime_t * node,
	   vlib_frame_t * frame)
{
  tapcli_main_t * tm = &tapcli_main;
  static u32 * ready_interface_indices;
  tapcli_interface_t * ti;
  int i;
  u32 total_count = 0;

  vec_reset_length (ready_interface_indices);
  clib_bitmap_foreach (i, tm->pending_read_bitmap,
  ({
    vec_add1 (ready_interface_indices, i);
  }));

  if (vec_len (ready_interface_indices) == 0)
    return 0;

  for (i = 0; i < vec_len(ready_interface_indices); i++)
  {
    tm->pending_read_bitmap =
        clib_bitmap_set (tm->pending_read_bitmap,
                         ready_interface_indices[i], 0);

    ti = vec_elt_at_index (tm->tapcli_interfaces, ready_interface_indices[i]);
    total_count += tapcli_rx_iface(vm, node, ti);
  }
  return total_count; //This might return more than 256.
}

/** TAPCLI error strings */
static char * tapcli_rx_error_strings[] = {
#define _(sym,string) string,
  foreach_tapcli_error
#undef _
};

VLIB_REGISTER_NODE (tapcli_rx_node, static) = {
  .function = tapcli_rx,
  .name = "tapcli-rx",
  .sibling_of = "device-input",
  .type = VLIB_NODE_TYPE_INPUT,
  .state = VLIB_NODE_STATE_INTERRUPT,
  .vector_size = 4,
  .n_errors = TAPCLI_N_ERROR,
  .error_strings = tapcli_rx_error_strings,
  .format_trace = format_tapcli_rx_trace,
};


/**
 * @brief Gets called when file descriptor is ready from epoll.
 *
 * @param *uf - unix_file_t
 *
 * @return error - clib_error_t
 *
 */
static clib_error_t * tapcli_read_ready (unix_file_t * uf)
{
  vlib_main_t * vm = vlib_get_main();
  tapcli_main_t * tm = &tapcli_main;
  uword * p;

  /** Schedule the rx node */
  vlib_node_set_interrupt_pending (vm, tapcli_rx_node.index);

  p = hash_get (tm->tapcli_interface_index_by_unix_fd, uf->file_descriptor);

  /** Mark the specific tap interface ready-to-read */
  if (p)
    tm->pending_read_bitmap = clib_bitmap_set (tm->pending_read_bitmap,
                                               p[0], 1);
  else
    clib_warning ("fd %d not in hash table", uf->file_descriptor);

  return 0;
}

/**
 * @brief CLI function for TAPCLI configuration
 *
 * @param *vm - vlib_main_t
 * @param *input - unformat_input_t
 *
 * @return error - clib_error_t
 *
 */
static clib_error_t *
tapcli_config (vlib_main_t * vm, unformat_input_t * input)
{
  tapcli_main_t *tm = &tapcli_main;
  const uword buffer_size = VLIB_BUFFER_DATA_SIZE;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "mtu %d", &tm->mtu_bytes))
	;
      else if (unformat (input, "disable"))
        tm->is_disabled = 1;
      else
          return clib_error_return (0, "unknown input `%U'",
                                    format_unformat_error, input);
    }

  if (tm->is_disabled)
    return 0;

  if (geteuid())
    {
      clib_warning ("tapcli disabled: must be superuser");
      tm->is_disabled = 1;
      return 0;
    }

  tm->mtu_buffers = (tm->mtu_bytes + (buffer_size - 1)) / buffer_size;

  return 0;
}

/**
 * @brief Renumber TAPCLI interface
 *
 * @param *hi - vnet_hw_interface_t
 * @param new_dev_instance - u32
 *
 * @return rc - int
 *
 */
static int tap_name_renumber (vnet_hw_interface_t * hi,
                              u32 new_dev_instance)
{
  tapcli_main_t *tm = &tapcli_main;

  vec_validate_init_empty (tm->show_dev_instance_by_real_dev_instance,
                           hi->dev_instance, ~0);

  tm->show_dev_instance_by_real_dev_instance [hi->dev_instance] =
    new_dev_instance;

  return 0;
}

VLIB_CONFIG_FUNCTION (tapcli_config, "tapcli");

/**
 * @brief Free "no punt" frame
 *
 * @param *vm - vlib_main_t
 * @param *node - vlib_node_runtime_t
 * @param *frame - vlib_frame_t
 *
 */
static void
tapcli_nopunt_frame (vlib_main_t * vm,
                   vlib_node_runtime_t * node,
                   vlib_frame_t * frame)
{
  u32 * buffers = vlib_frame_args (frame);
  uword n_packets = frame->n_vectors;
  vlib_buffer_free (vm, buffers, n_packets);
  vlib_frame_free (vm, node, frame);
}

VNET_HW_INTERFACE_CLASS (tapcli_interface_class,static) = {
  .name = "tapcli",
  .flags = VNET_HW_INTERFACE_CLASS_FLAG_P2P,
};

/**
 * @brief Formatter for TAPCLI interface name
 *
 * @param *s - formatter string
 * @param *args - va_list
 *
 * @return *s - formatted string
 *
 */
static u8 * format_tapcli_interface_name (u8 * s, va_list * args)
{
  u32 i = va_arg (*args, u32);
  u32 show_dev_instance = ~0;
  tapcli_main_t * tm = &tapcli_main;

  if (i < vec_len (tm->show_dev_instance_by_real_dev_instance))
    show_dev_instance = tm->show_dev_instance_by_real_dev_instance[i];

  if (show_dev_instance != ~0)
    i = show_dev_instance;

  s = format (s, "tap-%d", i);
  return s;
}

/**
 * @brief Modify interface flags for TAPCLI interface
 *
 * @param *vnm - vnet_main_t
 * @param *hw - vnet_hw_interface_t
 * @param flags - u32
 *
 * @return rc - u32
 *
 */
static u32 tapcli_flag_change (vnet_main_t * vnm,
                               vnet_hw_interface_t * hw,
                               u32 flags)
{
  tapcli_main_t *tm = &tapcli_main;
  tapcli_interface_t *ti;

   ti = vec_elt_at_index (tm->tapcli_interfaces, hw->dev_instance);

  if (flags & ETHERNET_INTERFACE_FLAG_MTU)
    {
      const uword buffer_size = VLIB_BUFFER_DATA_SIZE;
      tm->mtu_bytes = hw->max_packet_bytes;
      tm->mtu_buffers = (tm->mtu_bytes + (buffer_size - 1)) / buffer_size;
    }
   else
    {
      struct ifreq ifr;
      u32 want_promisc;

      memcpy (&ifr, &ti->ifr, sizeof (ifr));

      /* get flags, modify to bring up interface... */
      if (ioctl (ti->provision_fd, SIOCGIFFLAGS, &ifr) < 0)
        {
          clib_unix_warning ("Couldn't get interface flags for %s", hw->name);
          return 0;
        }

      want_promisc = (flags & ETHERNET_INTERFACE_FLAG_ACCEPT_ALL) != 0;

      if (want_promisc == ti->is_promisc)
        return 0;

      if (flags & ETHERNET_INTERFACE_FLAG_ACCEPT_ALL)
        ifr.ifr_flags |= IFF_PROMISC;
      else
        ifr.ifr_flags &= ~(IFF_PROMISC);

      /* get flags, modify to bring up interface... */
      if (ioctl (ti->provision_fd, SIOCSIFFLAGS, &ifr) < 0)
        {
          clib_unix_warning ("Couldn't set interface flags for %s", hw->name);
          return 0;
        }

      ti->is_promisc = want_promisc;
    }

  return 0;
}

/**
 * @brief Setting the TAP interface's next processing node
 *
 * @param *vnm - vnet_main_t
 * @param hw_if_index - u32
 * @param node_index - u32
 *
 */
static void tapcli_set_interface_next_node (vnet_main_t *vnm,
                                            u32 hw_if_index,
                                            u32 node_index)
{
  tapcli_main_t *tm = &tapcli_main;
  tapcli_interface_t *ti;
  vnet_hw_interface_t *hw = vnet_get_hw_interface (vnm, hw_if_index);

  ti = vec_elt_at_index (tm->tapcli_interfaces, hw->dev_instance);

  /** Shut off redirection */
  if (node_index == ~0)
    {
      ti->per_interface_next_index = node_index;
      return;
    }

  ti->per_interface_next_index =
    vlib_node_add_next (tm->vlib_main, tapcli_rx_node.index, node_index);
}

/**
 * @brief Set link_state == admin_state otherwise things like ip6 neighbor discovery breaks
 *
 * @param *vnm - vnet_main_t
 * @param hw_if_index - u32
 * @param flags - u32
 *
 * @return error - clib_error_t
 */
static clib_error_t *
tapcli_interface_admin_up_down (vnet_main_t * vnm, u32 hw_if_index, u32 flags)
{
  uword is_admin_up = (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) != 0;
  u32 hw_flags;
  u32 speed_duplex = VNET_HW_INTERFACE_FLAG_FULL_DUPLEX
    | VNET_HW_INTERFACE_FLAG_SPEED_1G;

  if (is_admin_up)
    hw_flags = VNET_HW_INTERFACE_FLAG_LINK_UP | speed_duplex;
  else
    hw_flags = speed_duplex;

  vnet_hw_interface_set_flags (vnm, hw_if_index, hw_flags);
  return 0;
}

VNET_DEVICE_CLASS (tapcli_dev_class,static) = {
  .name = "tapcli",
  .tx_function = tapcli_tx,
  .format_device_name = format_tapcli_interface_name,
  .rx_redirect_to_node = tapcli_set_interface_next_node,
  .name_renumber = tap_name_renumber,
  .admin_up_down_function = tapcli_interface_admin_up_down,
};

/**
 * @brief Dump TAP interfaces
 *
 * @param **out_tapids - tapcli_interface_details_t
 *
 * @return rc - int
 *
 */
int vnet_tap_dump_ifs (tapcli_interface_details_t **out_tapids)
{
  tapcli_main_t * tm = &tapcli_main;
  tapcli_interface_t * ti;

  tapcli_interface_details_t * r_tapids = NULL;
  tapcli_interface_details_t * tapid = NULL;

  vec_foreach (ti, tm->tapcli_interfaces) {
    if (!ti->active)
        continue;
    vec_add2(r_tapids, tapid, 1);
    tapid->sw_if_index = ti->sw_if_index;
    strncpy((char *)tapid->dev_name, ti->ifr.ifr_name, sizeof (ti->ifr.ifr_name)-1);
  }

  *out_tapids = r_tapids;

  return 0;
}

/**
 * @brief Get tap interface from inactive interfaces or create new
 *
 * @return interface - tapcli_interface_t
 *
 */
static tapcli_interface_t *tapcli_get_new_tapif()
{
  tapcli_main_t * tm = &tapcli_main;
  tapcli_interface_t *ti = NULL;

  int inactive_cnt = vec_len(tm->tapcli_inactive_interfaces);
  // if there are any inactive ifaces
  if (inactive_cnt > 0) {
    // take last
    u32 ti_idx = tm->tapcli_inactive_interfaces[inactive_cnt - 1];
    if (vec_len(tm->tapcli_interfaces) > ti_idx) {
      ti = vec_elt_at_index (tm->tapcli_interfaces, ti_idx);
      clib_warning("reusing tap interface");
    }
    // "remove" from inactive list
    _vec_len(tm->tapcli_inactive_interfaces) -= 1;
  }

  // ti was not retrieved from inactive ifaces - create new
  if (!ti)
    vec_add2 (tm->tapcli_interfaces, ti, 1);

  return ti;
}

typedef struct 
{
    ip6_address_t addr;
    u32 mask_width;
    unsigned int ifindex;
} ip6_ifreq_t;

/**
 * @brief Connect a TAP interface
 *
 * @param vm - vlib_main_t
 * @param ap - vnet_tap_connect_args_t 
 *
 * @return rc - int
 *
 */
int vnet_tap_connect (vlib_main_t * vm, vnet_tap_connect_args_t *ap)
{
  tapcli_main_t * tm = &tapcli_main;
  tapcli_interface_t * ti = NULL;
  struct ifreq ifr;
  int flags;
  int dev_net_tun_fd;
  int dev_tap_fd = -1;
  clib_error_t * error;
  u8 hwaddr [6];
  int rv = 0;

  if (tm->is_disabled)
    {
      return VNET_API_ERROR_FEATURE_DISABLED;
    }

  flags = IFF_TAP | IFF_NO_PI;

  if ((dev_net_tun_fd = open ("/dev/net/tun", O_RDWR)) < 0)
    return VNET_API_ERROR_SYSCALL_ERROR_1;

  memset (&ifr, 0, sizeof (ifr));
  strncpy(ifr.ifr_name, (char *) ap->intfc_name, sizeof (ifr.ifr_name)-1);
  ifr.ifr_flags = flags;
  if (ioctl (dev_net_tun_fd, TUNSETIFF, (void *)&ifr) < 0)
    {
      rv = VNET_API_ERROR_SYSCALL_ERROR_2;
      goto error;
    }
    
  /* Open a provisioning socket */
  if ((dev_tap_fd = socket(PF_PACKET, SOCK_RAW,
                           htons(ETH_P_ALL))) < 0 )
    {
      rv = VNET_API_ERROR_SYSCALL_ERROR_3;
      goto error;
    }

  /* Find the interface index. */
  {
    struct ifreq ifr;
    struct sockaddr_ll sll;

    memset (&ifr, 0, sizeof(ifr));
    strncpy (ifr.ifr_name, (char *) ap->intfc_name, sizeof (ifr.ifr_name)-1);
    if (ioctl (dev_tap_fd, SIOCGIFINDEX, &ifr) < 0 )
      {
        rv = VNET_API_ERROR_SYSCALL_ERROR_4;
        goto error;
      }

    /* Bind the provisioning socket to the interface. */
    memset(&sll, 0, sizeof(sll));
    sll.sll_family   = AF_PACKET;
    sll.sll_ifindex  = ifr.ifr_ifindex;
    sll.sll_protocol = htons(ETH_P_ALL);

    if (bind(dev_tap_fd, (struct sockaddr*) &sll, sizeof(sll)) < 0)
      {
        rv = VNET_API_ERROR_SYSCALL_ERROR_5;
        goto error;
      }
  }

  /* non-blocking I/O on /dev/tapX */
  {
    int one = 1;
    if (ioctl (dev_net_tun_fd, FIONBIO, &one) < 0)
      {
        rv = VNET_API_ERROR_SYSCALL_ERROR_6;
	goto error;
      }
  }
  ifr.ifr_mtu = tm->mtu_bytes;
  if (ioctl (dev_tap_fd, SIOCSIFMTU, &ifr) < 0)
    {
      rv = VNET_API_ERROR_SYSCALL_ERROR_7;
      goto error;
    }

  /* get flags, modify to bring up interface... */
  if (ioctl (dev_tap_fd, SIOCGIFFLAGS, &ifr) < 0)
    {
      rv = VNET_API_ERROR_SYSCALL_ERROR_8;
      goto error;
    }

  ifr.ifr_flags |= (IFF_UP | IFF_RUNNING);

  if (ioctl (dev_tap_fd, SIOCSIFFLAGS, &ifr) < 0)
    {
      rv = VNET_API_ERROR_SYSCALL_ERROR_9;
      goto error;
    }

  if (ap->ip4_address_set)
    {
      struct sockaddr_in sin;
      /* ip4: mask defaults to /24 */
      u32 mask = clib_host_to_net_u32 (0xFFFFFF00);

      memset(&sin, 0, sizeof(sin));
      sin.sin_family = AF_INET;
      /* sin.sin_port = 0; */
      sin.sin_addr.s_addr = ap->ip4_address->as_u32;
      memcpy (&ifr.ifr_ifru.ifru_addr, &sin, sizeof (sin));

      if (ioctl (dev_tap_fd, SIOCSIFADDR, &ifr) < 0)
        {
          rv = VNET_API_ERROR_SYSCALL_ERROR_10;
          goto error;
        }

      if (ap->ip4_mask_width > 0 && ap->ip4_mask_width < 33)
        {
          mask = ~0;
          mask <<= (32 - ap->ip4_mask_width);
        }

      mask = clib_host_to_net_u32(mask);
      sin.sin_family = AF_INET;
      sin.sin_port = 0;
      sin.sin_addr.s_addr = mask;
      memcpy (&ifr.ifr_ifru.ifru_addr, &sin, sizeof (sin));

      if (ioctl (dev_tap_fd, SIOCSIFNETMASK, &ifr) < 0)
        {
          rv = VNET_API_ERROR_SYSCALL_ERROR_10;
          goto error;
        }
    }

  if (ap->ip6_address_set)
    {
      struct ifreq ifr2;
      ip6_ifreq_t ifr6;
      int sockfd6;

      sockfd6 = socket(AF_INET6, SOCK_DGRAM, IPPROTO_IP);
      if (sockfd6 < 0)
        {
          rv = VNET_API_ERROR_SYSCALL_ERROR_10;
          goto error;
        }

      memset (&ifr2, 0, sizeof(ifr));
      strncpy (ifr2.ifr_name, (char *) ap->intfc_name, 
               sizeof (ifr2.ifr_name)-1);
      if (ioctl (sockfd6, SIOCGIFINDEX, &ifr2) < 0 )
        {
          close (sockfd6);
          rv = VNET_API_ERROR_SYSCALL_ERROR_4;
          goto error;
        }
      
      memcpy (&ifr6.addr, ap->ip6_address, sizeof (ip6_address_t));
      ifr6.mask_width = ap->ip6_mask_width;
      ifr6.ifindex = ifr2.ifr_ifindex;
      
      if (ioctl (sockfd6, SIOCSIFADDR, &ifr6) < 0)
        {
          close (sockfd6);
          clib_unix_warning ("ifr6");
          rv = VNET_API_ERROR_SYSCALL_ERROR_10;
          goto error;
        }
      close (sockfd6);
    }

  ti = tapcli_get_new_tapif();
  ti->per_interface_next_index = ~0;

  if (ap->hwaddr_arg != 0)
    clib_memcpy(hwaddr, ap->hwaddr_arg, 6);
  else
    {
      f64 now = vlib_time_now(vm);
      u32 rnd;
      rnd = (u32) (now * 1e6);
      rnd = random_u32 (&rnd);

      memcpy (hwaddr+2, &rnd, sizeof(rnd));
      hwaddr[0] = 2;
      hwaddr[1] = 0xfe;
    }

  error = ethernet_register_interface
        (tm->vnet_main,
         tapcli_dev_class.index,
         ti - tm->tapcli_interfaces /* device instance */,
         hwaddr /* ethernet address */,
         &ti->hw_if_index, 
         tapcli_flag_change);

  if (error)
    {
      clib_error_report (error);
      rv = VNET_API_ERROR_INVALID_REGISTRATION;
      goto error;
    }

  {
    unix_file_t template = {0};
    template.read_function = tapcli_read_ready;
    template.file_descriptor = dev_net_tun_fd;
    ti->unix_file_index = unix_file_add (&unix_main, &template);
    ti->unix_fd = dev_net_tun_fd;
    ti->provision_fd = dev_tap_fd;
    clib_memcpy (&ti->ifr, &ifr, sizeof (ifr));
  }
  
  {
    vnet_hw_interface_t * hw;
    hw = vnet_get_hw_interface (tm->vnet_main, ti->hw_if_index);
    hw->min_supported_packet_bytes = TAP_MTU_MIN;
    hw->max_supported_packet_bytes = TAP_MTU_MAX;
    hw->max_l3_packet_bytes[VLIB_RX] = hw->max_l3_packet_bytes[VLIB_TX] = hw->max_supported_packet_bytes - sizeof(ethernet_header_t);
    ti->sw_if_index = hw->sw_if_index;
    if (ap->sw_if_indexp)
      *(ap->sw_if_indexp) = hw->sw_if_index;
  }

  ti->active = 1;
  
  hash_set (tm->tapcli_interface_index_by_sw_if_index, ti->sw_if_index,
            ti - tm->tapcli_interfaces);
  
  hash_set (tm->tapcli_interface_index_by_unix_fd, ti->unix_fd,
            ti - tm->tapcli_interfaces);
  
  return rv;

 error:
  close (dev_net_tun_fd);
  if (dev_tap_fd >= 0)
      close (dev_tap_fd);

  return rv;
}

/**
 * @brief Renumber a TAP interface
 *
 * @param *vm - vlib_main_t
 * @param *intfc_name - u8
 * @param *hwaddr_arg - u8
 * @param *sw_if_indexp - u32
 * @param renumber - u8
 * @param custom_dev_instance - u32
 *
 * @return rc - int
 *
 */
int vnet_tap_connect_renumber (vlib_main_t * vm, 
                               vnet_tap_connect_args_t *ap)
{
  int rv = vnet_tap_connect(vm, ap);

  if (!rv && ap->renumber)
    vnet_interface_name_renumber (*(ap->sw_if_indexp), ap->custom_dev_instance);

  return rv;
}

/**
 * @brief Disconnect TAP CLI interface
 *
 * @param *ti - tapcli_interface_t
 *
 * @return rc - int
 *
 */
static int tapcli_tap_disconnect (tapcli_interface_t *ti)
{
  int rv = 0;
  vnet_main_t * vnm = vnet_get_main();
  tapcli_main_t * tm = &tapcli_main;
  u32 sw_if_index = ti->sw_if_index;

  // bring interface down
  vnet_sw_interface_set_flags (vnm, sw_if_index, 0);

  if (ti->unix_file_index != ~0) {
    unix_file_del (&unix_main, unix_main.file_pool + ti->unix_file_index);
    ti->unix_file_index = ~0;
  }
  else
    close(ti->unix_fd);

  hash_unset (tm->tapcli_interface_index_by_unix_fd, ti->unix_fd);
  hash_unset (tm->tapcli_interface_index_by_sw_if_index, ti->sw_if_index);
  close(ti->provision_fd);
  ti->unix_fd = -1;
  ti->provision_fd = -1;

  return rv;
}

/**
 * @brief Delete TAP interface
 *
 * @param *vm - vlib_main_t
 * @param sw_if_index - u32
 *
 * @return rc - int
 *
 */
int vnet_tap_delete(vlib_main_t *vm, u32 sw_if_index)
{
  int rv = 0;
  tapcli_main_t * tm = &tapcli_main;
  tapcli_interface_t *ti;
  uword *p = NULL;

  p = hash_get (tm->tapcli_interface_index_by_sw_if_index,
                sw_if_index);
  if (p == 0) {
    clib_warning ("sw_if_index %d unknown", sw_if_index);
    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
  }
  ti = vec_elt_at_index (tm->tapcli_interfaces, p[0]);

  // inactive
  ti->active = 0;
  tapcli_tap_disconnect(ti);
  // add to inactive list
  vec_add1(tm->tapcli_inactive_interfaces, ti - tm->tapcli_interfaces);

  // reset renumbered iface
  if (p[0] < vec_len (tm->show_dev_instance_by_real_dev_instance))
    tm->show_dev_instance_by_real_dev_instance[p[0]] = ~0;

  ethernet_delete_interface (tm->vnet_main, ti->hw_if_index);
  return rv;
}

/**
 * @brief CLI function to delete TAP interface
 *
 * @param *vm - vlib_main_t
 * @param *input - unformat_input_t
 * @param *cmd - vlib_cli_command_t
 *
 * @return error - clib_error_t
 *
 */
static clib_error_t *
tap_delete_command_fn (vlib_main_t * vm,
		 unformat_input_t * input,
		 vlib_cli_command_t * cmd)
{
  tapcli_main_t * tm = &tapcli_main;
  u32 sw_if_index = ~0;

  if (tm->is_disabled)
    {
      return clib_error_return (0, "device disabled...");
    }

  if (unformat (input, "%U", unformat_vnet_sw_interface, tm->vnet_main,
                &sw_if_index))
      ;
  else
    return clib_error_return (0, "unknown input `%U'",
                              format_unformat_error, input);


  int rc = vnet_tap_delete (vm, sw_if_index);

  if (!rc) {
    vlib_cli_output (vm, "Deleted.");
  } else {
    vlib_cli_output (vm, "Error during deletion of tap interface. (rc: %d)", rc);
  }

  return 0;
}

VLIB_CLI_COMMAND (tap_delete_command, static) = {
    .path = "tap delete",
    .short_help = "tap delete <vpp-tap-intfc-name>",
    .function = tap_delete_command_fn,
};

/**
 * @brief Modifies tap interface - can result in new interface being created
 *
 * @param *vm - vlib_main_t
 * @param orig_sw_if_index - u32
 * @param *intfc_name - u8
 * @param *hwaddr_arg - u8
 * @param *sw_if_indexp - u32
 * @param renumber - u8
 * @param custom_dev_instance - u32
 *
 * @return rc - int
 *
 */
int vnet_tap_modify (vlib_main_t * vm, vnet_tap_connect_args_t *ap)
{
    int rv = vnet_tap_delete (vm, ap->orig_sw_if_index);

    if (rv)
      return rv;

    rv = vnet_tap_connect_renumber(vm, ap);

    return rv;
}

/**
 * @brief CLI function to modify TAP interface
 *
 * @param *vm - vlib_main_t
 * @param *input - unformat_input_t
 * @param *cmd - vlib_cli_command_t
 *
 * @return error - clib_error_t
 *
 */
static clib_error_t *
tap_modify_command_fn (vlib_main_t * vm,
		 unformat_input_t * input,
		 vlib_cli_command_t * cmd)
{
  u8 * intfc_name;
  tapcli_main_t * tm = &tapcli_main;
  u32 sw_if_index = ~0;
  u32 new_sw_if_index = ~0;
  int user_hwaddr = 0;
  u8 hwaddr[6];
  vnet_tap_connect_args_t _a, *ap= &_a;

  if (tm->is_disabled)
    {
      return clib_error_return (0, "device disabled...");
    }

  if (unformat (input, "%U", unformat_vnet_sw_interface, tm->vnet_main,
                &sw_if_index))
      ;
  else
    return clib_error_return (0, "unknown input `%U'",
                              format_unformat_error, input);

  if (unformat (input, "%s", &intfc_name))
    ;
  else
    return clib_error_return (0, "unknown input `%U'",
                              format_unformat_error, input);

  if (unformat(input, "hwaddr %U", unformat_ethernet_address,
               &hwaddr))
    user_hwaddr = 1;


  memset (ap, 0, sizeof(*ap));
  ap->orig_sw_if_index = sw_if_index;
  ap->intfc_name = intfc_name;
  ap->sw_if_indexp = &new_sw_if_index;
  if (user_hwaddr)
    ap->hwaddr_arg = hwaddr;

  int rc = vnet_tap_modify (vm, ap);

  if (!rc) {
    vlib_cli_output (vm, "Modified %U for Linux tap '%s'",
                   format_vnet_sw_if_index_name, tm->vnet_main, 
                     *(ap->sw_if_indexp), ap->intfc_name);
  } else {
    vlib_cli_output (vm, "Error during modification of tap interface. (rc: %d)", rc);
  }

  return 0;
}

VLIB_CLI_COMMAND (tap_modify_command, static) = {
    .path = "tap modify",
    .short_help = "tap modify <vpp-tap-intfc-name> <linux-intfc-name> [hwaddr <addr>]",
    .function = tap_modify_command_fn,
};

/**
 * @brief CLI function to connect TAP interface
 *
 * @param *vm - vlib_main_t
 * @param *input - unformat_input_t
 * @param *cmd - vlib_cli_command_t
 *
 * @return error - clib_error_t
 *
 */
static clib_error_t *
tap_connect_command_fn (vlib_main_t * vm,
		 unformat_input_t * input,
		 vlib_cli_command_t * cmd)
{
  u8 * intfc_name = 0;
  unformat_input_t _line_input, *line_input = &_line_input;
  vnet_tap_connect_args_t _a, *ap= &_a;
  tapcli_main_t * tm = &tapcli_main;
  u8 hwaddr[6];
  u8 *hwaddr_arg = 0;
  u32 sw_if_index;
  ip4_address_t ip4_address;
  int ip4_address_set = 0;
  ip6_address_t ip6_address;
  int ip6_address_set = 0;
  u32 ip4_mask_width = 0;
  u32 ip6_mask_width = 0;
  clib_error_t *error = NULL;

  if (tm->is_disabled)
    return clib_error_return (0, "device disabled...");

  if (!unformat_user (input, unformat_line_input, line_input))
    return 0;

  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat(line_input, "hwaddr %U", unformat_ethernet_address,
                   &hwaddr))
        hwaddr_arg = hwaddr;
      
      /* It is here for backward compatibility */
      else if (unformat(line_input, "hwaddr random"))
        ;
      
      else if (unformat (line_input, "address %U/%d",
                         unformat_ip4_address, &ip4_address, &ip4_mask_width))
        ip4_address_set = 1;
      
      else if (unformat (line_input, "address %U/%d",
                         unformat_ip6_address, &ip6_address, &ip6_mask_width))
        ip6_address_set = 1;
      
      else if (unformat (line_input, "%s", &intfc_name))
        ;
      else
        {
          error = clib_error_return (0, "unknown input `%U'",
                                     format_unformat_error, line_input);
          goto done;
        }
    }
  
  if (intfc_name == 0)
    {
      error = clib_error_return (0, "interface name must be specified");
      goto done;
    }

  memset (ap, 0, sizeof (*ap));

  ap->intfc_name = intfc_name;
  ap->hwaddr_arg = hwaddr_arg;
  if (ip4_address_set)
    {
      ap->ip4_address = &ip4_address;
      ap->ip4_mask_width = ip4_mask_width;
      ap->ip4_address_set = 1;
    }
  if (ip6_address_set)
    {
      ap->ip6_address = &ip6_address;
      ap->ip6_mask_width = ip6_mask_width;
      ap->ip6_address_set = 1;
    }

  ap->sw_if_indexp = &sw_if_index;

  int rv = vnet_tap_connect(vm, ap);

  switch (rv) 
    {
    case VNET_API_ERROR_SYSCALL_ERROR_1:
      error = clib_error_return (0, "Couldn't open /dev/net/tun");
      goto done;
      
    case VNET_API_ERROR_SYSCALL_ERROR_2:
      error = clib_error_return (0, "Error setting flags on '%s'", intfc_name);
      goto done;

    case VNET_API_ERROR_SYSCALL_ERROR_3:
      error = clib_error_return (0,  "Couldn't open provisioning socket");
      goto done;

    case VNET_API_ERROR_SYSCALL_ERROR_4:
      error = clib_error_return (0,  "Couldn't get if_index");
      goto done;
    
    case VNET_API_ERROR_SYSCALL_ERROR_5:
      error = clib_error_return (0,  "Couldn't bind provisioning socket");
      goto done;

    case VNET_API_ERROR_SYSCALL_ERROR_6:
      error = clib_error_return (0,  "Couldn't set device non-blocking flag");
      goto done;

    case VNET_API_ERROR_SYSCALL_ERROR_7:
      error = clib_error_return (0,  "Couldn't set device MTU");
      goto done;

    case VNET_API_ERROR_SYSCALL_ERROR_8:
      error = clib_error_return (0,  "Couldn't get interface flags");
      goto done;

    case VNET_API_ERROR_SYSCALL_ERROR_9:
      error = clib_error_return (0,  "Couldn't set intfc admin state up");
      goto done;

    case VNET_API_ERROR_SYSCALL_ERROR_10:
      error = clib_error_return (0,  "Couldn't set intfc address/mask");
      goto done;

    case VNET_API_ERROR_INVALID_REGISTRATION:
      error = clib_error_return (0,  "Invalid registration");
      goto done;

    case 0:
      break;

    default:
      error = clib_error_return (0,  "Unknown error: %d", rv);
      goto done;
    }

  vlib_cli_output(vm, "%U\n", format_vnet_sw_if_index_name, 
                  vnet_get_main(), sw_if_index);

done:
  unformat_free (line_input);

  return error;
}

VLIB_CLI_COMMAND (tap_connect_command, static) = {
    .path = "tap connect",
    .short_help =
	"tap connect <intfc-name> [address <ip-addr>/mw] [hwaddr <addr>]",
    .function = tap_connect_command_fn,
};

/**
 * @brief TAPCLI main init
 *
 * @param *vm - vlib_main_t
 *
 * @return error - clib_error_t
 *
 */
clib_error_t *
tapcli_init (vlib_main_t * vm)
{
  tapcli_main_t * tm = &tapcli_main;

  tm->vlib_main = vm;
  tm->vnet_main = vnet_get_main();
  tm->unix_main = &unix_main;
  tm->mtu_bytes = TAP_MTU_DEFAULT;
  tm->tapcli_interface_index_by_sw_if_index = hash_create (0, sizeof(uword));
  tm->tapcli_interface_index_by_unix_fd = hash_create (0, sizeof (uword));
  tm->rx_buffers = 0;
  vec_alloc(tm->rx_buffers, VLIB_FRAME_SIZE);
  vec_reset_length(tm->rx_buffers);
  vm->os_punt_frame = tapcli_nopunt_frame;
  return 0;
}

VLIB_INIT_FUNCTION (tapcli_init);