aboutsummaryrefslogtreecommitdiffstats
path: root/src/plugins/nat/nat.h
blob: d2b114afbbecda7d3f8d960a6d166f111d284861 (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
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
/*
 * Copyright (c) 2016 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 NAT plugin global declarations
 */
#ifndef __included_nat_h__
#define __included_nat_h__

#include <vnet/vnet.h>
#include <vnet/ip/ip.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/ip/icmp46_packet.h>
#include <vnet/api_errno.h>
#include <vnet/fib/fib_source.h>
#include <vppinfra/elog.h>
#include <vppinfra/bihash_8_8.h>
#include <vppinfra/bihash_16_8.h>
#include <vppinfra/dlist.h>
#include <vppinfra/error.h>
#include <vlibapi/api.h>
#include <vlib/log.h>
#include <vppinfra/bihash_16_8.h>

/* default session timeouts */
#define SNAT_UDP_TIMEOUT 300
#define SNAT_TCP_TRANSITORY_TIMEOUT 240
#define SNAT_TCP_ESTABLISHED_TIMEOUT 7440
#define SNAT_ICMP_TIMEOUT 60

/* number of worker handoff frame queue elements */
#define NAT_FQ_NELTS 64

/* NAT buffer flags */
#define SNAT_FLAG_HAIRPINNING (1 << 0)

typedef struct
{
  u32 arc_next;
} nat_buffer_opaque_t;

typedef enum
{
  NAT_NEXT_DROP,
  NAT_NEXT_ICMP_ERROR,
  NAT_NEXT_IN2OUT_PRE,
  NAT_NEXT_OUT2IN_PRE,
  NAT_NEXT_IN2OUT_ED_FAST_PATH,
  NAT_NEXT_IN2OUT_ED_SLOW_PATH,
  NAT_NEXT_IN2OUT_ED_OUTPUT_SLOW_PATH,
  NAT_NEXT_OUT2IN_ED_FAST_PATH,
  NAT_NEXT_OUT2IN_ED_SLOW_PATH,
  NAT_N_NEXT,
} nat_next_t;

typedef struct
{
  u32 next_index;
} nat_pre_trace_t;

#define nat_buffer_opaque(b) \
  ((nat_buffer_opaque_t *)((vnet_buffer_opaque2_t *)b->opaque2)->__unused2)

/*
STATIC_ASSERT (sizeof (nat_buffer_opaque_t) <=
               STRUCT_SIZE_OF (vnet_buffer_opaque_t, unused),
               "Custom meta-data too large for vnet_buffer_opaque_t");

#define nat_buffer_opaque(b) \
  ((nat_buffer_opaque_t *)((u8 *)((b)->opaque) + \
    STRUCT_OFFSET_OF (vnet_buffer_opaque_t, unused)))*/

/* session key (4-tuple) */
typedef struct
{
  union
  {
    struct
    {
      ip4_address_t addr;
      u16 port;
      u16 protocol:3, fib_index:13;
    };
    u64 as_u64;
  };
} snat_session_key_t;

/* endpoint-dependent session key (6-tuple) */
typedef struct
{
  union
  {
    struct
    {
      ip4_address_t l_addr;
      ip4_address_t r_addr;
      u32 proto:8, fib_index:24;
      u16 l_port;
      u16 r_port;
    };
    u64 as_u64[2];
  };
} nat_ed_ses_key_t;

/* deterministic session outside key */
typedef struct
{
  union
  {
    struct
    {
      ip4_address_t ext_host_addr;
      u16 ext_host_port;
      u16 out_port;
    };
    u64 as_u64;
  };
} snat_det_out_key_t;

/* user (internal host) key */
typedef struct
{
  union
  {
    struct
    {
      ip4_address_t addr;
      u32 fib_index;
    };
    u64 as_u64;
  };
} snat_user_key_t;

typedef struct
{
  u32 sw_if_index;
  u32 next_index;
  u8 cached;
} nat44_reass_trace_t;

/* NAT API Configuration flags */
#define foreach_nat_config_flag \
  _(0x01, IS_TWICE_NAT)         \
  _(0x02, IS_SELF_TWICE_NAT)    \
  _(0x04, IS_OUT2IN_ONLY)       \
  _(0x08, IS_ADDR_ONLY)         \
  _(0x10, IS_OUTSIDE)           \
  _(0x20, IS_INSIDE)            \
  _(0x40, IS_STATIC)            \
  _(0x80, IS_EXT_HOST_VALID)    \

typedef enum nat_config_flags_t_
{
#define _(n,f) NAT_API_##f = n,
  foreach_nat_config_flag
#undef _
} nat_config_flags_t;

/* External address and port allocation modes */
#define foreach_nat_addr_and_port_alloc_alg \
  _(0, DEFAULT, "default")         \
  _(1, MAPE, "map-e")              \
  _(2, RANGE, "port-range")

typedef enum
{
#define _(v, N, s) NAT_ADDR_AND_PORT_ALLOC_ALG_##N = v,
  foreach_nat_addr_and_port_alloc_alg
#undef _
} nat_addr_and_port_alloc_alg_t;


/* Supported L4 protocols */
#define foreach_snat_protocol \
  _(UDP, 0, udp, "udp")       \
  _(TCP, 1, tcp, "tcp")       \
  _(ICMP, 2, icmp, "icmp")

typedef enum
{
#define _(N, i, n, s) SNAT_PROTOCOL_##N = i,
  foreach_snat_protocol
#undef _
} snat_protocol_t;


/* Session state */
#define foreach_snat_session_state          \
  _(0, UNKNOWN, "unknown")                 \
  _(1, UDP_ACTIVE, "udp-active")           \
  _(2, TCP_SYN_SENT, "tcp-syn-sent")       \
  _(3, TCP_ESTABLISHED, "tcp-established") \
  _(4, TCP_FIN_WAIT, "tcp-fin-wait")       \
  _(5, TCP_CLOSE_WAIT, "tcp-close-wait")   \
  _(6, TCP_CLOSING, "tcp-closing")         \
  _(7, TCP_LAST_ACK, "tcp-last-ack")       \
  _(8, TCP_CLOSED, "tcp-closed")           \
  _(9, ICMP_ACTIVE, "icmp-active")

typedef enum
{
#define _(v, N, s) SNAT_SESSION_##N = v,
  foreach_snat_session_state
#undef _
} snat_session_state_t;

#define foreach_nat_in2out_ed_error                     \
_(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
_(IN2OUT_PACKETS, "good in2out packets processed")      \
_(OUT_OF_PORTS, "out of ports")                         \
_(BAD_ICMP_TYPE, "unsupported ICMP type")               \
_(MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")   \
_(MAX_USER_SESS_EXCEEDED, "max user sessions exceeded") \
_(DROP_FRAGMENT, "drop fragment")                       \
_(MAX_REASS, "maximum reassemblies exceeded")           \
_(MAX_FRAG, "maximum fragments per reassembly exceeded")\
_(CANNOT_CREATE_USER, "cannot create NAT user")         \
_(NON_SYN, "non-SYN packet try to create session")      \
_(TCP_PACKETS, "TCP packets")                           \
_(TCP_CLOSED, "drops due to TCP in transitory timeout") \
_(UDP_PACKETS, "UDP packets")                           \
_(ICMP_PACKETS, "ICMP packets")                         \
_(OTHER_PACKETS, "other protocol packets")              \
_(FRAGMENTS, "fragments")                               \
_(CACHED_FRAGMENTS, "cached fragments")                 \
_(PROCESSED_FRAGMENTS, "processed fragments")

typedef enum
{
#define _(sym,str) NAT_IN2OUT_ED_ERROR_##sym,
  foreach_nat_in2out_ed_error
#undef _
    NAT_IN2OUT_ED_N_ERROR,
} nat_in2out_ed_error_t;

#define foreach_nat_out2in_ed_error                     \
_(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
_(OUT2IN_PACKETS, "good out2in packets processed")      \
_(OUT_OF_PORTS, "out of ports")                         \
_(BAD_ICMP_TYPE, "unsupported ICMP type")               \
_(NO_TRANSLATION, "no translation")                     \
_(MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")   \
_(MAX_USER_SESS_EXCEEDED, "max user sessions exceeded") \
_(DROP_FRAGMENT, "drop fragment")                       \
_(MAX_REASS, "maximum reassemblies exceeded")           \
_(MAX_FRAG, "maximum fragments per reassembly exceeded")\
_(CANNOT_CREATE_USER, "cannot create NAT user")         \
_(NON_SYN, "non-SYN packet try to create session")      \
_(TCP_PACKETS, "TCP packets")                           \
_(TCP_CLOSED, "drops due to TCP in transitory timeout") \
_(UDP_PACKETS, "UDP packets")                           \
_(ICMP_PACKETS, "ICMP packets")                         \
_(OTHER_PACKETS, "other protocol packets")              \
_(FRAGMENTS, "fragments")                               \
_(CACHED_FRAGMENTS, "cached fragments")                 \
_(PROCESSED_FRAGMENTS, "processed fragments")

typedef enum
{
#define _(sym,str) NAT_OUT2IN_ED_ERROR_##sym,
  foreach_nat_out2in_ed_error
#undef _
    NAT_OUT2IN_ED_N_ERROR,
} nat_out2in_ed_error_t;


/* Endpoint dependent TCP session state */
#define NAT44_SES_I2O_FIN 1
#define NAT44_SES_O2I_FIN 2
#define NAT44_SES_I2O_FIN_ACK 4
#define NAT44_SES_O2I_FIN_ACK 8
#define NAT44_SES_I2O_SYN 16
#define NAT44_SES_O2I_SYN 32
#define NAT44_SES_RST     64

/* Session flags */
#define SNAT_SESSION_FLAG_STATIC_MAPPING       1
#define SNAT_SESSION_FLAG_UNKNOWN_PROTO        2
#define SNAT_SESSION_FLAG_LOAD_BALANCING       4
#define SNAT_SESSION_FLAG_TWICE_NAT            8
#define SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT   16
#define SNAT_SESSION_FLAG_FWD_BYPASS           32
#define SNAT_SESSION_FLAG_AFFINITY             64
#define SNAT_SESSION_FLAG_OUTPUT_FEATURE       128

/* NAT interface flags */
#define NAT_INTERFACE_FLAG_IS_INSIDE 1
#define NAT_INTERFACE_FLAG_IS_OUTSIDE 2

/* Static mapping flags */
#define NAT_STATIC_MAPPING_FLAG_ADDR_ONLY    1
#define NAT_STATIC_MAPPING_FLAG_OUT2IN_ONLY  2
#define NAT_STATIC_MAPPING_FLAG_IDENTITY_NAT 4
#define NAT_STATIC_MAPPING_FLAG_LB           8

/* *INDENT-OFF* */
typedef CLIB_PACKED(struct
{
  /* Outside network key */
  snat_session_key_t out2in;

  /* Inside network key */
  snat_session_key_t in2out;

  /* Flags */
  u32 flags;

  /* Per-user translations */
  u32 per_user_index;
  u32 per_user_list_head_index;

  /* index in global LRU list */
  u32 global_lru_index;
  f64 last_lru_update;

  /* Last heard timer */
  f64 last_heard;

  /* Last HA refresh */
  f64 ha_last_refreshed;

  /* Counters */
  u64 total_bytes;
  u32 total_pkts;

  /* External host address and port */
  ip4_address_t ext_host_addr;
  u16 ext_host_port;

  /* External host address and port after translation */
  ip4_address_t ext_host_nat_addr;
  u16 ext_host_nat_port;

  /* TCP session state */
  u8 state;
  u32 i2o_fin_seq;
  u32 o2i_fin_seq;
  u32 tcp_close_timestamp;

  /* user index */
  u32 user_index;
}) snat_session_t;
/* *INDENT-ON* */


typedef struct
{
  ip4_address_t addr;
  u32 fib_index;
  u32 sessions_per_user_list_head_index;
  u32 nsessions;
  u32 nstaticsessions;
  /* discovered minimum session timeout time */
  u64 min_session_timeout;
} snat_user_t;

typedef struct
{
  ip4_address_t addr;
  u32 fib_index;
/* *INDENT-OFF* */
#define _(N, i, n, s) \
  u16 busy_##n##_ports; \
  u16 * busy_##n##_ports_per_thread; \
  u32 busy_##n##_port_refcounts[65535];
  foreach_snat_protocol
#undef _
/* *INDENT-ON* */
} snat_address_t;

typedef struct
{
  u32 fib_index;
  u32 refcount;
} nat_outside_fib_t;

typedef struct
{
  /* Inside network port */
  u16 in_port;
  /* Outside network address and port */
  snat_det_out_key_t out;
  /* Session state */
  u8 state;
  /* Expire timeout */
  u32 expire;
} snat_det_session_t;

typedef struct
{
  /* inside IP address range */
  ip4_address_t in_addr;
  u8 in_plen;
  /* outside IP address range */
  ip4_address_t out_addr;
  u8 out_plen;
  /* inside IP addresses / outside IP addresses */
  u32 sharing_ratio;
  /* number of ports available to internal host */
  u16 ports_per_host;
  /* session counter */
  u32 ses_num;
  /* vector of sessions */
  snat_det_session_t *sessions;
} snat_det_map_t;

typedef struct
{
  /* backend IP address */
  ip4_address_t addr;
  /* backend port number */
  u16 port;
  /* probability of the backend to be randomly matched */
  u8 probability;
  u8 prefix;
  /* backend FIB table */
  u32 vrf_id;
  u32 fib_index;
} nat44_lb_addr_port_t;

typedef enum
{
  /* twice-nat disabled */
  TWICE_NAT_DISABLED,
  /* twice-nat enabled */
  TWICE_NAT,
  /* twice-nat only when src IP equals dst IP after translation */
  TWICE_NAT_SELF,
} twice_nat_type_t;

typedef enum
{
  /* no load-balancing */
  NO_LB_NAT,
  /* load-balancing */
  LB_NAT,
  /* load-balancing with affinity */
  AFFINITY_LB_NAT,
} lb_nat_type_t;

typedef struct
{
  /* local IP address */
  ip4_address_t local_addr;
  /* external IP address */
  ip4_address_t external_addr;
  /* local port */
  u16 local_port;
  /* external port */
  u16 external_port;
  /* is twice-nat */
  twice_nat_type_t twice_nat;
  /* local FIB table */
  u32 vrf_id;
  u32 fib_index;
  /* protocol */
  snat_protocol_t proto;
  /* 0 = disabled, otherwise client IP affinity sticky time in seconds */
  u32 affinity;
  /* worker threads used by backends/local host */
  u32 *workers;
  /* opaque string tag */
  u8 *tag;
  /* backends for load-balancing mode */
  nat44_lb_addr_port_t *locals;
  /* affinity per service lis */
  u32 affinity_per_service_list_head_index;
  /* flags */
  u32 flags;
} snat_static_mapping_t;

typedef struct
{
  u32 sw_if_index;
  u8 flags;
} snat_interface_t;

typedef struct
{
  ip4_address_t l_addr;
  u16 l_port;
  u16 e_port;
  u32 sw_if_index;
  u32 vrf_id;
  snat_protocol_t proto;
  u32 flags;
  int addr_only;
  int twice_nat;
  int is_add;
  int out2in_only;
  int identity_nat;
  u8 *tag;
} snat_static_map_resolve_t;

typedef struct
{
  /* Main lookup tables */
  clib_bihash_8_8_t out2in;
  clib_bihash_8_8_t in2out;

  /* Endpoint dependent sessions lookup tables */
  clib_bihash_16_8_t out2in_ed;
  clib_bihash_16_8_t in2out_ed;

  /* Find-a-user => src address lookup */
  clib_bihash_8_8_t user_hash;

  /* User pool */
  snat_user_t *users;

  /* Session pool */
  snat_session_t *sessions;

  /* Pool of doubly-linked list elements */
  dlist_elt_t *list_pool;

  /* LRU session list - head is stale, tail is fresh */
  dlist_elt_t *global_lru_pool;
  u32 global_lru_head_index;

  /* NAT thread index */
  u32 snat_thread_index;

  /* real thread index */
  u32 thread_index;

  /* discovered minimum session timeout time */
  u64 min_session_timeout;

  /* session scavenging */
  u32 cleared;
  u32 cleanup_runs;
  f64 cleanup_timeout;

} snat_main_per_thread_data_t;

struct snat_main_s;

/* ICMP session match function */
typedef u32 (snat_icmp_match_function_t) (struct snat_main_s * sm,
					  vlib_node_runtime_t * node,
					  u32 thread_index,
					  vlib_buffer_t * b0,
					  ip4_header_t * ip0, u8 * p_proto,
					  snat_session_key_t * p_value,
					  u8 * p_dont_translate, void *d,
					  void *e);

/* Return worker thread index for given packet */
typedef u32 (snat_get_worker_in2out_function_t) (ip4_header_t * ip,
						 u32 rx_fib_index,
						 u8 is_output);

typedef u32 (snat_get_worker_out2in_function_t) (vlib_buffer_t * b,
						 ip4_header_t * ip,
						 u32 rx_fib_index,
						 u8 is_output);

/* NAT address and port allacotaion function */
typedef int (nat_alloc_out_addr_and_port_function_t) (snat_address_t *
						      addresses,
						      u32 fib_index,
						      u32 thread_index,
						      snat_session_key_t * k,
						      u16 port_per_thread,
						      u32 snat_thread_index);

typedef struct ed_bihash_key_s
{
  u32 src_address;
  u32 dst_address;
  u16 src_port;
  u16 dst_port;
  u8 protocol;
} ed_bihash_key_t;

typedef struct ed_bihash_kv_s
{
  union
  {
    ed_bihash_key_t k;
    clib_bihash_kv_16_8_t kv;
  };
} ed_bihash_kv_t;

STATIC_ASSERT (STRUCT_SIZE_OF (ed_bihash_kv_t, k) <=
	       STRUCT_SIZE_OF (ed_bihash_kv_t, kv.key),
	       "ed key needs to fit in bihash key");

typedef struct snat_main_s
{
  /* ICMP session match functions */
  snat_icmp_match_function_t *icmp_match_in2out_cb;
  snat_icmp_match_function_t *icmp_match_out2in_cb;

  /* Thread settings */
  u32 num_workers;
  u32 first_worker_index;
  u32 *workers;
  snat_get_worker_in2out_function_t *worker_in2out_cb;
  snat_get_worker_out2in_function_t *worker_out2in_cb;
  u16 port_per_thread;
  u32 num_snat_thread;

  /* Per thread data */
  snat_main_per_thread_data_t *per_thread_data;

  /* Find a static mapping by local */
  clib_bihash_8_8_t static_mapping_by_local;

  /* Find a static mapping by external */
  clib_bihash_8_8_t static_mapping_by_external;

  /* Static mapping pool */
  snat_static_mapping_t *static_mappings;

  /* Interface pool */
  snat_interface_t *interfaces;
  snat_interface_t *output_feature_interfaces;

  /* Vector of outside addresses */
  snat_address_t *addresses;
  /* Address and port allocation function */
  nat_alloc_out_addr_and_port_function_t *alloc_addr_and_port;
  /* Address and port allocation type */
  nat_addr_and_port_alloc_alg_t addr_and_port_alloc_alg;
  /* Port set parameters (MAP-E) */
  u8 psid_offset;
  u8 psid_length;
  u16 psid;
  /* Port range parameters */
  u16 start_port;
  u16 end_port;

  /* vector of outside fibs */
  nat_outside_fib_t *outside_fibs;

  /* Vector of twice NAT addresses for extenal hosts */
  snat_address_t *twice_nat_addresses;

  /* sw_if_indices whose intfc addresses should be auto-added */
  u32 *auto_add_sw_if_indices;
  u32 *auto_add_sw_if_indices_twice_nat;

  /* vector of interface address static mappings to resolve. */
  snat_static_map_resolve_t *to_resolve;

  /* Randomize port allocation order */
  u32 random_seed;

  /* Worker handoff frame-queue index */
  u32 fq_in2out_index;
  u32 fq_in2out_output_index;
  u32 fq_out2in_index;

  /* node indexes */
  u32 error_node_index;

  /* handoff fq nodes  */
  u32 handoff_out2in_index;
  u32 handoff_in2out_index;
  u32 handoff_in2out_output_index;

  /* respect feature arc nodes */
  u32 pre_out2in_node_index;
  u32 pre_in2out_node_index;

  u32 in2out_node_index;
  u32 in2out_output_node_index;
  u32 in2out_fast_node_index;
  u32 in2out_slowpath_node_index;
  u32 in2out_slowpath_output_node_index;
  u32 ed_in2out_node_index;
  u32 ed_in2out_slowpath_node_index;
  u32 out2in_node_index;
  u32 out2in_fast_node_index;
  u32 ed_out2in_node_index;
  u32 ed_out2in_slowpath_node_index;
  u32 det_in2out_node_index;
  u32 det_out2in_node_index;

  u32 hairpinning_node_index;
  u32 hairpin_dst_node_index;
  u32 hairpin_src_node_index;
  u32 ed_hairpinning_node_index;
  u32 ed_hairpin_dst_node_index;
  u32 ed_hairpin_src_node_index;


  /* Deterministic NAT mappings */
  snat_det_map_t *det_maps;

  /* If forwarding is enabled */
  u8 forwarding_enabled;

  /* Config parameters */
  u8 static_mapping_only;
  u8 static_mapping_connection_tracking;
  u8 deterministic;
  u8 out2in_dpo;
  u8 endpoint_dependent;
  u32 translation_buckets;
  u32 translation_memory_size;
  u32 max_translations;
  u32 user_buckets;
  u32 user_memory_size;
  u32 max_translations_per_user;
  u32 outside_vrf_id;
  u32 outside_fib_index;
  u32 inside_vrf_id;
  u32 inside_fib_index;

  /* values of various timeouts */

  // min timeout of all proto timeouts
  u32 min_timeout;
  // proto timeouts
  u32 udp_timeout;
  u32 tcp_transitory_timeout;
  u32 tcp_established_timeout;
  u32 icmp_timeout;

  /* TCP MSS clamping */
  u16 mss_clamping;
  u16 mss_value_net;

  /* counters/gauges */
  vlib_simple_counter_main_t total_users;
  vlib_simple_counter_main_t total_sessions;

  /* API message ID base */
  u16 msg_id_base;

  /* log class */
  vlib_log_class_t log_class;
  /* logging level */
  u8 log_level;

  /* convenience */
  vlib_main_t *vlib_main;
  vnet_main_t *vnet_main;
  ip4_main_t *ip4_main;
  ip_lookup_main_t *ip4_lookup_main;
  api_main_t *api_main;

  clib_bihash_16_8_t ed_ext_ports;
} snat_main_t;

typedef struct
{
  u32 thread_index;
  f64 now;
} nat44_is_idle_session_ctx_t;

typedef struct
{
  u32 cached_sw_if_index;
  u32 cached_ip4_address;
} snat_runtime_t;

extern snat_main_t snat_main;

// nat pre ed next_node feature classification
extern vlib_node_registration_t nat_default_node;
extern vlib_node_registration_t nat_pre_in2out_node;
extern vlib_node_registration_t nat_pre_out2in_node;

extern vlib_node_registration_t snat_in2out_node;
extern vlib_node_registration_t snat_in2out_output_node;
extern vlib_node_registration_t snat_out2in_node;
extern vlib_node_registration_t snat_in2out_worker_handoff_node;
extern vlib_node_registration_t snat_in2out_output_worker_handoff_node;
extern vlib_node_registration_t snat_out2in_worker_handoff_node;
extern vlib_node_registration_t snat_det_in2out_node;
extern vlib_node_registration_t snat_det_out2in_node;
extern vlib_node_registration_t nat44_ed_in2out_node;
extern vlib_node_registration_t nat44_ed_in2out_output_node;
extern vlib_node_registration_t nat44_ed_out2in_node;

extern fib_source_t nat_fib_src_hi;
extern fib_source_t nat_fib_src_low;

/* format functions */
format_function_t format_snat_user;
format_function_t format_snat_user_v2;
format_function_t format_snat_static_mapping;
format_function_t format_snat_static_map_to_resolve;
format_function_t format_snat_session;
format_function_t format_det_map_ses;
format_function_t format_snat_key;
format_function_t format_static_mapping_key;
format_function_t format_snat_protocol;
format_function_t format_nat_addr_and_port_alloc_alg;
/* unformat functions */
unformat_function_t unformat_snat_protocol;

/** \brief Check if SNAT session is created from static mapping.
    @param s SNAT session
    @return 1 if SNAT session is created from static mapping otherwise 0
*/
#define snat_is_session_static(s) (s->flags & SNAT_SESSION_FLAG_STATIC_MAPPING)

/** \brief Check if SNAT session for unknown protocol.
    @param s SNAT session
    @return 1 if SNAT session for unknown protocol otherwise 0
*/
#define snat_is_unk_proto_session(s) (s->flags & SNAT_SESSION_FLAG_UNKNOWN_PROTO)

/** \brief Check if NAT session is twice NAT.
    @param s NAT session
    @return 1 if NAT session is twice NAT
*/
#define is_twice_nat_session(s) (s->flags & SNAT_SESSION_FLAG_TWICE_NAT)

/** \brief Check if NAT session is load-balancing.
    @param s NAT session
    @return 1 if NAT session is load-balancing
*/
#define is_lb_session(s) (s->flags & SNAT_SESSION_FLAG_LOAD_BALANCING)

/** \brief Check if NAT session is forwarding bypass.
    @param s NAT session
    @return 1 if NAT session is load-balancing
*/
#define is_fwd_bypass_session(s) (s->flags & SNAT_SESSION_FLAG_FWD_BYPASS)

/** \brief Check if NAT session is endpoint dependent.
    @param s NAT session
    @return 1 if NAT session is endpoint dependent
*/
#define is_ed_session(s) (s->flags & SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT)

/** \brief Check if NAT session has affinity record.
    @param s NAT session
    @return 1 if NAT session has affinity record
*/
#define is_affinity_sessions(s) (s->flags & SNAT_SESSION_FLAG_AFFINITY)

/** \brief Check if NAT interface is inside.
    @param i NAT interfce
    @return 1 if inside interface
*/
#define nat_interface_is_inside(i) i->flags & NAT_INTERFACE_FLAG_IS_INSIDE

/** \brief Check if NAT interface is outside.
    @param i NAT interfce
    @return 1 if outside interface
*/
#define nat_interface_is_outside(i) i->flags & NAT_INTERFACE_FLAG_IS_OUTSIDE

/** \brief Check if NAT44 endpoint-dependent TCP session is closed.
    @param s NAT session
    @return 1 if session is closed
*/
#define nat44_is_ses_closed(s) s->state == 0xf

/** \brief Check if NAT static mapping is address only (1:1NAT).
    @param sm NAT static mapping
    @return 1 if 1:1NAT, 0 if 1:1NAPT
*/
#define is_addr_only_static_mapping(sm) (sm->flags & NAT_STATIC_MAPPING_FLAG_ADDR_ONLY)

/** \brief Check if NAT static mapping match only out2in direction.
    @param sm NAT static mapping
    @return 1 if rule match only out2in direction
*/
#define is_out2in_only_static_mapping(sm) (sm->flags & NAT_STATIC_MAPPING_FLAG_OUT2IN_ONLY)

/** \brief Check if NAT static mapping is identity NAT.
    @param sm NAT static mapping
    @return 1 if identity NAT
*/
#define is_identity_static_mapping(sm) (sm->flags & NAT_STATIC_MAPPING_FLAG_IDENTITY_NAT)

/** \brief Check if NAT static mapping is load-balancing.
    @param sm NAT static mapping
    @return 1 if load-balancing
*/
#define is_lb_static_mapping(sm) (sm->flags & NAT_STATIC_MAPPING_FLAG_LB)

/** \brief Check if client initiating TCP connection (received SYN from client)
    @param t TCP header
    @return 1 if client initiating TCP connection
*/
always_inline bool
tcp_flags_is_init (u8 f)
{
  return (f & TCP_FLAG_SYN) && !(f & TCP_FLAG_ACK);
}

/* logging */
#define nat_log_err(...) \
  vlib_log(VLIB_LOG_LEVEL_ERR, snat_main.log_class, __VA_ARGS__)
#define nat_log_warn(...) \
  vlib_log(VLIB_LOG_LEVEL_WARNING, snat_main.log_class, __VA_ARGS__)
#define nat_log_notice(...) \
  vlib_log(VLIB_LOG_LEVEL_NOTICE, snat_main.log_class, __VA_ARGS__)
#define nat_log_info(...) \
  vlib_log(VLIB_LOG_LEVEL_INFO, snat_main.log_class, __VA_ARGS__)
#define nat_log_debug(...)\
  vlib_log(VLIB_LOG_LEVEL_DEBUG, snat_main.log_class, __VA_ARGS__)

/* NAT API Logging Levels */
#define foreach_nat_log_level \
  _(0x00, LOG_NONE)           \
  _(0x01, LOG_ERROR)          \
  _(0x02, LOG_WARNING)        \
  _(0x03, LOG_NOTICE)         \
  _(0x04, LOG_INFO)           \
  _(0x05, LOG_DEBUG)

typedef enum nat_log_level_t_
{
#define _(n,f) SNAT_##f = n,
  foreach_nat_log_level
#undef _
} nat_log_level_t;

#define nat_elog(_level, _str)                    \
do                                                \
  {                                               \
    snat_main_t *sm = &snat_main;                 \
    if (PREDICT_FALSE (sm->log_level >= _level))  \
      {                                           \
        ELOG_TYPE_DECLARE (e) =                   \
          {                                       \
            .format = "nat-msg " _str,            \
            .format_args = "",                    \
          };                                      \
        ELOG_DATA (&sm->vlib_main->elog_main, e); \
      }                                           \
  } while (0);

#define nat_elog_addr(_level, _str, _addr)               \
do                                                       \
  {                                                      \
    if (PREDICT_FALSE (sm->log_level >= _level))         \
      {                                                  \
        ELOG_TYPE_DECLARE (e) =                          \
          {                                              \
            .format = "nat-msg " _str " %d.%d.%d.%d",    \
            .format_args = "i1i1i1i1",                   \
          };                                             \
        CLIB_PACKED(struct                               \
          {                                              \
            u8 oct1;                                     \
            u8 oct2;                                     \
            u8 oct3;                                     \
            u8 oct4;                                     \
          }) *ed;                                        \
        ed = ELOG_DATA (&vlib_global_main.elog_main, e); \
        ed->oct4 = _addr >> 24;                          \
        ed->oct3 = _addr >> 16;                          \
        ed->oct2 = _addr >> 8;                           \
        ed->oct1 = _addr;                                \
    }                                                    \
  } while (0);

#define nat_elog_debug_handoff(_str, _tid, _fib, _src, _dst)                \
do                                                                          \
  {                                                                         \
  if (PREDICT_FALSE (sm->log_level >= SNAT_LOG_DEBUG))                      \
    {                                                                       \
      ELOG_TYPE_DECLARE (e) =                                               \
        {                                                                   \
          .format = "nat-msg " _str " ip src: %d.%d.%d.%d dst: %d.%d.%d.%d" \
                                    " tid from: %d to: %d fib: %d",         \
        .format_args = "i1i1i1i1i1i1i1i1i4i4i4",                            \
      };                                                                    \
      CLIB_PACKED(struct                                                    \
        {                                                                   \
          u8 src_oct1;                                                      \
          u8 src_oct2;                                                      \
          u8 src_oct3;                                                      \
          u8 src_oct4;                                                      \
          u8 dst_oct1;                                                      \
          u8 dst_oct2;                                                      \
          u8 dst_oct3;                                                      \
          u8 dst_oct4;                                                      \
          u32 ftid;                                                         \
          u32 ttid;                                                         \
          u32 fib;                                                          \
        }) *ed;                                                             \
      ed = ELOG_DATA (&vlib_global_main.elog_main, e);                      \
      ed->src_oct1 = _src >> 24;                                            \
      ed->src_oct2 = _src >> 16;                                            \
      ed->src_oct3 = _src >> 8;                                             \
      ed->src_oct4 = _src;                                                  \
      ed->dst_oct1 = _dst >> 24;                                            \
      ed->dst_oct2 = _dst >> 16;                                            \
      ed->dst_oct3 = _dst >> 8;                                             \
      ed->dst_oct4 = _dst;                                                  \
      ed->ftid = vlib_get_thread_index ();                                  \
      ed->ttid = _tid;                                                      \
      ed->fib = _fib;                                                       \
    }                                                                       \
  } while (0);

#define nat_elog_debug_handoff_v2(_str, _prt, _fib, _src, _dst)              \
do                                                                           \
  {                                                                          \
  if (PREDICT_FALSE (sm->log_level >= SNAT_LOG_DEBUG))                       \
    {                                                                        \
      ELOG_TYPE_DECLARE (e) =                                                \
        {                                                                    \
          .format = "nat-msg " _str " ip_src:%d.%d.%d.%d ip_dst:%d.%d.%d.%d" \
                                    " tid:%d prt:%d fib:%d",                 \
        .format_args = "i1i1i1i1i1i1i1i1i4i4i4",                             \
      };                                                                     \
      CLIB_PACKED(struct                                                     \
        {                                                                    \
          u8 src_oct1;                                                       \
          u8 src_oct2;                                                       \
          u8 src_oct3;                                                       \
          u8 src_oct4;                                                       \
          u8 dst_oct1;                                                       \
          u8 dst_oct2;                                                       \
          u8 dst_oct3;                                                       \
          u8 dst_oct4;                                                       \
          u32 tid;                                                           \
          u32 prt;                                                           \
          u32 fib;                                                           \
        }) *ed;                                                              \
      ed = ELOG_DATA (&vlib_global_main.elog_main, e);                       \
      ed->src_oct1 = _src >> 24;                                             \
      ed->src_oct2 = _src >> 16;                                             \
      ed->src_oct3 = _src >> 8;                                              \
      ed->src_oct4 = _src;                                                   \
      ed->dst_oct1 = _dst >> 24;                                             \
      ed->dst_oct2 = _dst >> 16;                                             \
      ed->dst_oct3 = _dst >> 8;                                              \
      ed->dst_oct4 = _dst;                                                   \
      ed->tid = vlib_get_thread_index ();                                    \
      ed->prt = _prt;                                                        \
      ed->fib = _fib;                                                        \
    }                                                                        \
  } while (0);

#define nat_elog_X1(_level, _fmt, _arg, _val1)         \
do                                                     \
  {                                                    \
    snat_main_t *sm = &snat_main;                      \
    if (PREDICT_FALSE (sm->log_level >= _level))       \
      {                                                \
        ELOG_TYPE_DECLARE (e) =                        \
          {                                            \
            .format = "nat-msg " _fmt,                 \
            .format_args = _arg,                       \
          };                                           \
        CLIB_PACKED(struct                             \
          {                                            \
            typeof (_val1) val1;                       \
          }) *ed;                                      \
        ed = ELOG_DATA (&sm->vlib_main->elog_main, e); \
        ed->val1 = _val1;                              \
      }                                                \
  } while (0);

#define nat_elog_notice(nat_elog_str) \
  nat_elog(SNAT_LOG_INFO, "[notice] " nat_elog_str)
#define nat_elog_warn(nat_elog_str) \
  nat_elog(SNAT_LOG_WARNING, "[warning] " nat_elog_str)
#define nat_elog_err(nat_elog_str) \
  nat_elog(SNAT_LOG_ERROR, "[error] " nat_elog_str)
#define nat_elog_debug(nat_elog_str) \
  nat_elog(SNAT_LOG_DEBUG, "[debug] " nat_elog_str)
#define nat_elog_info(nat_elog_str) \
  nat_elog(SNAT_LOG_INFO, "[info] " nat_elog_str)

#define nat_elog_notice_X1(nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1) \
  nat_elog_X1(SNAT_LOG_NOTICE, "[notice] " nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1)
#define nat_elog_warn_X1(nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1) \
  nat_elog_X1(SNAT_LOG_WARNING, "[warning] " nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1)
#define nat_elog_err_X1(nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1) \
  nat_elog_X1(SNAT_LOG_ERROR, "[error] " nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1)
#define nat_elog_debug_X1(nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1) \
  nat_elog_X1(SNAT_LOG_DEBUG, "[debug] " nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1)
#define nat_elog_info_X1(nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1) \
  nat_elog_X1(SNAT_LOG_INFO, "[info] " nat_elog_fmt_str, nat_elog_fmt_arg, nat_elog_val1)

/* ICMP session match functions */
u32 icmp_match_in2out_fast (snat_main_t * sm, vlib_node_runtime_t * node,
			    u32 thread_index, vlib_buffer_t * b0,
			    ip4_header_t * ip0, u8 * p_proto,
			    snat_session_key_t * p_value,
			    u8 * p_dont_translate, void *d, void *e);
u32 icmp_match_in2out_slow (snat_main_t * sm, vlib_node_runtime_t * node,
			    u32 thread_index, vlib_buffer_t * b0,
			    ip4_header_t * ip0, u8 * p_proto,
			    snat_session_key_t * p_value,
			    u8 * p_dont_translate, void *d, void *e);
u32 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
			    u32 thread_index, vlib_buffer_t * b0,
			    ip4_header_t * ip0, u8 * p_proto,
			    snat_session_key_t * p_value,
			    u8 * p_dont_translate, void *d, void *e);
u32 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
			    u32 thread_index, vlib_buffer_t * b0,
			    ip4_header_t * ip0, u8 * p_proto,
			    snat_session_key_t * p_value,
			    u8 * p_dont_translate, void *d, void *e);

/* ICMP deterministic NAT session match functions */
u32 icmp_match_out2in_det (snat_main_t * sm, vlib_node_runtime_t * node,
			   u32 thread_index, vlib_buffer_t * b0,
			   ip4_header_t * ip0, u8 * p_proto,
			   snat_session_key_t * p_value,
			   u8 * p_dont_translate, void *d, void *e);
u32 icmp_match_in2out_det (snat_main_t * sm, vlib_node_runtime_t * node,
			   u32 thread_index, vlib_buffer_t * b0,
			   ip4_header_t * ip0, u8 * p_proto,
			   snat_session_key_t * p_value,
			   u8 * p_dont_translate, void *d, void *e);

/* ICMP endpoint-dependent session match functions */
u32 icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
			  u32 thread_index, vlib_buffer_t * b0,
			  ip4_header_t * ip0, u8 * p_proto,
			  snat_session_key_t * p_value,
			  u8 * p_dont_translate, void *d, void *e);
u32 icmp_match_in2out_ed (snat_main_t * sm, vlib_node_runtime_t * node,
			  u32 thread_index, vlib_buffer_t * b0,
			  ip4_header_t * ip0, u8 * p_proto,
			  snat_session_key_t * p_value,
			  u8 * p_dont_translate, void *d, void *e);

u32 icmp_in2out (snat_main_t * sm, vlib_buffer_t * b0, ip4_header_t * ip0,
		 icmp46_header_t * icmp0, u32 sw_if_index0, u32 rx_fib_index0,
		 vlib_node_runtime_t * node, u32 next0, u32 thread_index,
		 void *d, void *e);

u32 icmp_out2in (snat_main_t * sm, vlib_buffer_t * b0, ip4_header_t * ip0,
		 icmp46_header_t * icmp0, u32 sw_if_index0, u32 rx_fib_index0,
		 vlib_node_runtime_t * node, u32 next0, u32 thread_index,
		 void *d, void *e);

/* hairpinning functions */
u32 snat_icmp_hairpinning (snat_main_t * sm, vlib_buffer_t * b0,
			   ip4_header_t * ip0, icmp46_header_t * icmp0,
			   int is_ed);
void nat_hairpinning_sm_unknown_proto (snat_main_t * sm, vlib_buffer_t * b,
				       ip4_header_t * ip);
void nat44_ed_hairpinning_unknown_proto (snat_main_t * sm, vlib_buffer_t * b,
					 ip4_header_t * ip);
int snat_hairpinning (snat_main_t * sm, vlib_buffer_t * b0,
		      ip4_header_t * ip0, udp_header_t * udp0,
		      tcp_header_t * tcp0, u32 proto0, int is_ed);
void nat44_reass_hairpinning (snat_main_t * sm, vlib_buffer_t * b0,
			      ip4_header_t * ip0, u16 sport, u16 dport,
			      u32 proto0, int is_ed);

/* Call back functions for clib_bihash_add_or_overwrite_stale */
int nat44_i2o_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg);
int nat44_o2i_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg);
int nat44_i2o_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg);
int nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg);

/**
 * @brief Add external address to NAT44 pool
 *
 * @param addr      IPv4 address
 * @param vrf_id    VRF id of tenant, ~0 means independent of VRF
 * @param twice_nat 1 if twice NAT address
 *
 * @return 0 on success, non-zero value otherwise
 */
int snat_add_address (snat_main_t * sm, ip4_address_t * addr, u32 vrf_id,
		      u8 twice_nat);

/**
 * @brief Delete external address from NAT44 pool
 *
 * @param addr      IPv4 address
 * @param delete_sm 1 if delete static mapping using address
 * @param twice_nat 1 if twice NAT address
 *
 * @return 0 on success, non-zero value otherwise
 */
int snat_del_address (snat_main_t * sm, ip4_address_t addr, u8 delete_sm,
		      u8 twice_nat);

/**
 * @brief Add/delete external address to FIB DPO (out2in DPO mode)
 *
 * @param addr   IPv4 address
 * @param is_add 1 = add, 0 = delete
 *
 * @return 0 on success, non-zero value otherwise
 */
void nat44_add_del_address_dpo (ip4_address_t addr, u8 is_add);

/**
 * @brief Add/delete NAT44 static mapping
 *
 * @param l_addr       local IPv4 address
 * @param e_addr       external IPv4 address
 * @param l_port       local port number
 * @param e_port       external port number
 * @param vrf_id       local VRF ID
 * @param addr_only    1 = 1:1NAT, 0 = 1:1NAPT
 * @param sw_if_index  use interface address as external IPv4 address
 * @param proto        L4 protocol
 * @param is_add       1 = add, 0 = delete
 * @param twice_nat    twice-nat mode
 * @param out2in_only  if 1 rule match only out2in direction
 * @param tag          opaque string tag
 * @param identity_nat identity NAT
 *
 * @return 0 on success, non-zero value otherwise
 */
int snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
			     u16 l_port, u16 e_port, u32 vrf_id,
			     int addr_only, u32 sw_if_index,
			     snat_protocol_t proto, int is_add,
			     twice_nat_type_t twice_nat, u8 out2in_only,
			     u8 * tag, u8 identity_nat);

/**
 * @brief Add/delete static mapping with load-balancing (multiple backends)
 *
 * @param e_addr      external IPv4 address
 * @param e_port      external port number
 * @param proto       L4 protocol
 * @param locals      list of local backends
 * @param is_add      1 = add, 0 = delete
 * @param twice_nat   twice-nat mode
 * @param out2in_only if 1 rule match only out2in direction
 * @param tag         opaque string tag
 * @param affinity    0 = disabled, otherwise client IP affinity sticky time
 *
 * @return 0 on success, non-zero value otherwise
 */
int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
				     snat_protocol_t proto,
				     nat44_lb_addr_port_t * locals, u8 is_add,
				     twice_nat_type_t twice_nat,
				     u8 out2in_only, u8 * tag, u32 affinity);

int nat44_lb_static_mapping_add_del_local (ip4_address_t e_addr, u16 e_port,
					   ip4_address_t l_addr, u16 l_port,
					   snat_protocol_t proto, u32 vrf_id,
					   u8 probability, u8 is_add);

clib_error_t *snat_api_init (vlib_main_t * vm, snat_main_t * sm);

/**
 * @brief Set NAT plugin workers
 *
 * @param bitmap NAT workers bitmap
 *
 * @return 0 on success, non-zero value otherwise
 */
int snat_set_workers (uword * bitmap);

/**
 * @brief Enable/disable NAT44 feature on the interface
 *
 * @param sw_if_index software index of the interface
 * @param is_inside   1 = inside, 0 = outside
 * @param is_del      1 = delete, 0 = add
 *
 * @return 0 on success, non-zero value otherwise
 */
int snat_interface_add_del (u32 sw_if_index, u8 is_inside, int is_del);

/**
 * @brief Enable/disable NAT44 output feature on the interface (postrouting NAT)
 *
 * @param sw_if_index software index of the interface
 * @param is_inside   1 = inside, 0 = outside
 * @param is_del      1 = delete, 0 = add
 *
 * @return 0 on success, non-zero value otherwise
 */
int snat_interface_add_del_output_feature (u32 sw_if_index, u8 is_inside,
					   int is_del);

/**
 * @brief Add/delete NAT44 pool address from specific interfce
 *
 * @param sw_if_index software index of the interface
 * @param is_del      1 = delete, 0 = add
 * @param twice_nat   1 = twice NAT address for extenal hosts
 *
 * @return 0 on success, non-zero value otherwise
 */
int snat_add_interface_address (snat_main_t * sm, u32 sw_if_index, int is_del,
				u8 twice_nat);

/**
 * @brief Delete NAT44 session
 *
 * @param addr   IPv4 address
 * @param port   L4 port number
 * @param proto  L4 protocol
 * @param vrf_id VRF ID
 * @param is_in  1 = inside network address and port pair, 0 = outside
 *
 * @return 0 on success, non-zero value otherwise
 */
int nat44_del_session (snat_main_t * sm, ip4_address_t * addr, u16 port,
		       snat_protocol_t proto, u32 vrf_id, int is_in);

/**
 * @brief Delete NAT44 endpoint-dependent session
 *
 * @param addr   IPv4 address
 * @param port   L4 port number
 * @param proto  L4 protocol
 * @param vrf_id VRF ID
 * @param is_in  1 = inside network address and port pair, 0 = outside
 *
 * @return 0 on success, non-zero value otherwise
 */
int nat44_del_ed_session (snat_main_t * sm, ip4_address_t * addr, u16 port,
			  ip4_address_t * eh_addr, u16 eh_port, u8 proto,
			  u32 vrf_id, int is_in);

/**
 * @brief Free NAT44 session data (lookup keys, external addrres port)
 *
 * @param s            NAT session
 * @param thread_index thread index
 * @param is_ha        is HA event
 */
void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
			    u32 thread_index, u8 is_ha);

/**
 * @brief Free NAT44 ED session data (lookup keys, external addrres port)
 *
 * @param s            NAT session
 * @param thread_index thread index
 * @param is_ha        is HA event
 */
void
nat44_free_session_data (snat_main_t * sm, snat_session_t * s,
			 u32 thread_index, u8 is_ha);
/**
 * @brief Find or create NAT user
 *
 * @param addr         IPv4 address
 * @param fib_index    FIB table index
 * @param thread_index thread index
 *
 * @return NAT user data structure on success otherwise zero value
 */
snat_user_t *nat_user_get_or_create (snat_main_t * sm,
				     ip4_address_t * addr, u32 fib_index,
				     u32 thread_index);

/**
 * @brief Allocate new NAT session or recycle last used
 *
 * @param u            NAT user
 * @param thread_index thread index
 *
 * @return session data structure on success otherwise zero value
 */
snat_session_t *nat_session_alloc_or_recycle (snat_main_t * sm,
					      snat_user_t * u,
					      u32 thread_index, f64 now);

/**
 * @brief Allocate NAT endpoint-dependent session
 *
 * @param u            NAT user
 * @param thread_index thread index
 *
 * @return session data structure on success otherwise zero value
 */
snat_session_t *nat_ed_session_alloc (snat_main_t * sm, snat_user_t * u,
				      u32 thread_index, f64 now);

/**
 * @brief Set address and port assignment algorithm for MAP-E CE
 *
 * @param psid        Port Set Identifier value
 * @param psid_offset number of offset bits
 * @param psid_length length of PSID
 */
void nat_set_alloc_addr_and_port_mape (u16 psid, u16 psid_offset,
				       u16 psid_length);

/**
 * @brief Set address and port assignment algorithm for port range
 *
 * @param start_port beginning of the port range
 * @param end_port   end of the port range
 */
void nat_set_alloc_addr_and_port_range (u16 start_port, u16 end_port);

/**
 * @brief Set address and port assignment algorithm to default/standard
 */
void nat_set_alloc_addr_and_port_default (void);

/**
 * @brief Free outside address and port pair
 *
 * @param addresses    vector of outside addresses
 * @param thread_index thread index
 * @param k            address, port and protocol
 */
void snat_free_outside_address_and_port (snat_address_t * addresses,
					 u32 thread_index,
					 snat_session_key_t * k);

/**
 * @brief Alloc outside address and port
 *
 * @param addresses         vector of outside addresses
 * @param fib_index         FIB table index
 * @param thread_index      thread index
 * @param k                 allocated address and port pair
 * @param port_per_thread   number of ports per threead
 * @param snat_thread_index NAT thread index
 *
 * @return 0 on success, non-zero value otherwise
 */
int snat_alloc_outside_address_and_port (snat_address_t * addresses,
					 u32 fib_index,
					 u32 thread_index,
					 snat_session_key_t * k,
					 u16 port_per_thread,
					 u32 snat_thread_index);

/**
 * @brief Match NAT44 static mapping.
 *
 * @param match         address and port to match
 * @param mapping       external/local address and port of the matched mapping
 * @param by_external   if 0 match by local address otherwise match by external
 *                      address
 * @param is_addr_only  1 if matched mapping is address only
 * @param twice_nat     matched mapping is twice NAT type
 * @param lb            1 if matched mapping is load-balanced
 * @param ext_host_addr external host address
 *
 * @returns 0 if match found otherwise 1.
 */
int snat_static_mapping_match (snat_main_t * sm,
			       snat_session_key_t match,
			       snat_session_key_t * mapping,
			       u8 by_external,
			       u8 * is_addr_only,
			       twice_nat_type_t * twice_nat,
			       lb_nat_type_t * lb,
			       ip4_address_t * ext_host_addr,
			       u8 * is_identity_nat);

/**
 * @brief Add/del NAT address to FIB.
 *
 * Add the external NAT address to the FIB as receive entries. This ensures
 * that VPP will reply to ARP for this address and we don't need to enable
 * proxy ARP on the outside interface.
 *
 * @param addr        IPv4 address
 * @param plen        address prefix length
 * @param sw_if_index software index of the outside interface
 * @param is_add      0 = delete, 1 = add.
 */
void snat_add_del_addr_to_fib (ip4_address_t * addr,
			       u8 p_len, u32 sw_if_index, int is_add);

/*
 * Why is this here? Because we don't need to touch this layer to
 * simply reply to an icmp. We need to change id to a unique
 * value to NAT an echo request/reply.
 */

typedef struct
{
  u16 identifier;
  u16 sequence;
} icmp_echo_header_t;

typedef struct
{
  u16 src_port, dst_port;
} tcp_udp_header_t;

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