aboutsummaryrefslogtreecommitdiffstats
path: root/hicn-plugin/src/faces/face.h
blob: 43900dd4e9f276560c6ab099d6dd284a8035793a (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
/*
 * Copyright (c) 2021 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.
 */

#ifndef __HICN_FACE_H__
#define __HICN_FACE_H__

#include <vnet/fib/fib_node.h>
#include <vnet/vnet.h>
#include <vlib/vlib.h>
#include <vnet/ip/ip46_address.h>
#include <vnet/dpo/dpo.h>
#include <vnet/adj/adj_types.h>
#include <vppinfra/bihash_8_8.h>
#include <vnet/adj/adj_midchain.h>

#include <vpp_plugins/hicn/error.h>

#include "face_flags.h"
#include "../hicn_buffer_flags.h"
#include "../hicn_logging.h"

typedef u8 hicn_face_flags_t;
typedef index_t hicn_face_id_t;

/**
 * @file face.h
 *
 * This file implements a general face type. The purpose of a face is to
 * carry the needed information to forward interest and data packets to the
 * next node in the network. There are two type of faces: complete faces (in
 * short faces), and incomplete faces (in short ifaces).
 *
 * A face that does not contain the indication of the adjacency is an
 * incomplete face (iface), otherwise it is considered to be complete. Ifaces
 * are used to forward data back to the previous hICN hop from which we
 * received an interest, while faces are used to forward interest packets to
 * the next hicn node. Faces and ifaces are created at two different points in
 * time. Faces are created when a route is added, while ifaces are created when
 * an interest is received. In details, faces and ifaces carry the following
 * information:
 * - nat_addr: the ip address to perform src nat or dst nat on interest and
 * data packets, respectively;
 * - pl_id: the path label
 * - locks: the number of entities using this face. When 0 the face can be
 * deallocated
 * - dpo: the dpo that identifies the next node in the vlib graph for
 * processing the vlib buffer. The dpo contains the dpo.dpoi_next field that
 * points to the next node in the vlib graph and the dpo.dpoi_index which is an
 * index to adj used by the next node to perform the l2 rewrite. In case of
 * ifaces, it is likely we don't know the adjacency when creting the face. In
 * this case, the next node in the vlib graph will be the node that performs a
 * lookup in the fib. Only in case of udp tunnels, which are bidirectional
 * tunnel we know that the incoming tunnel is also the outgoing one, therefore
 * in this case we store the tunnel in the dpo.dpoi_index fields. For all the
 * other tunnels (which are most likely unidirectional), the source address of
 *   the interest will be used to retrieve the outgoing tunnel when sending the
 * corresponding data back.
 * - sw_if: the incoming interface of the interest
 * - fib_node, fib_entry_index and fib_sibling are information used to be
 * notified of changes in the adjacency pointed by the dpo.
 *
 * We maintain one hash tables to retrieve faces and ifaces, which indexes
 * faces and ifaces for nat_address, sw_if and dpo.
 */

/**
 * @brief Structure representing a face. It containes the fields shared among
 * all the types of faces as well it leaves some space for storing additional
 * information specific to each type.
 */
typedef struct __attribute__ ((packed)) hicn_face_s
{
  /* Flags to idenfity if the face is incomplete (iface), complete (face) */
  /* And a network or application face (1B) */
  hicn_face_flags_t flags;

  /* Align the upcoming fields */
  u8 iface_next;

  /* Path label (2B) */
  u16 pl_id;

  /* Number of dpo holding a reference to the dpoi (4B) */
  u32 locks;

  /* Dpo for the adjacency (8B) */
  union
  {
    dpo_id_t dpo;
    u64 align_dpo;
  };

  /* Local address of the interface sw_if */
  ip46_address_t nat_addr;

  /* local interface for the local ip address */
  u32 sw_if;

  fib_node_t fib_node;

  fib_node_index_t fib_entry_index;

  u32 fib_sibling;
} hicn_face_t;

/* Pool of faces */
extern hicn_face_t *hicn_dpoi_face_pool;

#define HICN_FACE_NULL (hicn_face_id_t) ~0

/**
 * @brief Definition of the virtual functin table for an hICN FACE DPO.
 */
typedef struct hicn_face_vft_s
{
  u8 *(*format_face) (u8 *s, va_list *args);
  /**< Format an hICN face dpo*/
  int (*hicn_face_del) (hicn_face_id_t face_id);
  void (*hicn_face_get_dpo) (hicn_face_t *face, dpo_id_t *dpo);
} hicn_face_vft_t;

#define foreach_hicn_face_counter                                             \
  _ (INTEREST_RX, 0, "Interest rx")                                           \
  _ (INTEREST_TX, 1, "Interest tx")                                           \
  _ (DATA_RX, 2, "Data rx")                                                   \
  _ (DATA_TX, 3, "Data tx")

typedef enum
{
#define _(a, b, c) HICN_FACE_COUNTERS_##a = (b),
  foreach_hicn_face_counter
#undef _
    HICN_N_COUNTER
} hicn_face_counters_t;

extern mhash_t hicn_face_hashtb;

extern const char *HICN_FACE_CTRX_STRING[];

#define get_face_counter_string(ctrxno)                                       \
  (char *) (HICN_FACE_CTRX_STRING[ctrxno])

/* Vector maintaining a dpo per face */
extern dpo_id_t *face_dpo_vec;
extern hicn_face_vft_t *face_vft_vec;

/* Vector holding the set of face names */
extern char **face_type_names_vec;

/* Pathlabel counter */
extern u8 pl_index;

/* First face type registered in the sytem.*/
extern dpo_type_t first_type;

/* Per-face counters */
extern vlib_combined_counter_main_t *counters;

/**
 * @brief Return the face id from the face object
 *
 * @param Pointer to the face state
 * @return face id
 */
always_inline hicn_face_id_t
hicn_dpoi_get_index (hicn_face_t *face_dpoi)
{
  return face_dpoi - hicn_dpoi_face_pool;
}

/**
 * @brief Return the face object from the face id.
 * This method is robust to invalid face id.
 *
 * @param dpoi_index Face identifier
 * @return Pointer to the face or NULL
 */
always_inline hicn_face_t *
hicn_dpoi_get_from_idx_safe (hicn_face_id_t dpoi_index)
{
  if (!pool_is_free_index (hicn_dpoi_face_pool, dpoi_index))
    return (hicn_face_t *) pool_elt_at_index (hicn_dpoi_face_pool, dpoi_index);
  else
    return NULL;
}

/**
 * @brief Return the face from the face id. Face id must be valid.
 *
 * @param dpoi_index Face identifier
 * @return Pointer to the face
 */
always_inline hicn_face_t *
hicn_dpoi_get_from_idx (hicn_face_id_t dpoi_index)
{
  return (hicn_face_t *) pool_elt_at_index (hicn_dpoi_face_pool, dpoi_index);
}

/**
 * @brief Return true if the face id belongs to an existing face
 */
always_inline int
hicn_dpoi_idx_is_valid (hicn_face_id_t face_id)
{
  return pool_len (hicn_dpoi_face_pool) > face_id &&
	 !pool_is_free_index (hicn_dpoi_face_pool, face_id);
}

/**
 * @brief Delete a face
 *
 * @param face_id Id of the face to delete
 * @return HICN_ERROR_FACE_NOT_FOUND if the face does not exist, otherwise
 * HICN_ERROR_NONE
 */
int hicn_face_del (hicn_face_id_t face_id);

/**
 * @brief Add a lock to the face dpo
 *
 * @param dpo Pointer to the face dpo
 */
always_inline void
hicn_face_lock_with_id (hicn_face_id_t face_id)
{
  hicn_face_t *face;
  face = hicn_dpoi_get_from_idx (face_id);
  face->locks++;
}

/**
 * @brief Remove a lock to the face dpo. Deallocate the face id locks == 0
 *
 * @param dpo Pointer to the face dpo
 */
always_inline int
hicn_face_unlock_with_id (hicn_face_id_t face_id)
{
  hicn_face_t *face;
  face = hicn_dpoi_get_from_idx (face_id);

  if (face->locks > 0)
    {
      face->locks--;

      if (face->locks == 0)
	{
	  HICN_DEBUG ("Deleting face %d", face_id);
	  return hicn_face_del (face_id);
	}
    }

  return HICN_ERROR_NONE;
}

/**
 * @brief Add a lock to the face through its dpo
 *
 * @param dpo Pointer to the face dpo
 */
always_inline void
hicn_face_lock (dpo_id_t *dpo)
{
  hicn_face_lock_with_id (dpo->dpoi_index);
}

/**
 * @brief Remove a lock to the face through its dpo. Deallocate the face id
 * locks == 0
 *
 * @param dpo Pointer to the face dpo
 */
always_inline void
hicn_face_unlock (dpo_id_t *dpo)
{
  hicn_face_unlock_with_id (dpo->dpoi_index);
}

/**
 * @brief Init the internal structures of the face module
 *
 * Must be called before processing any packet
 */
void hicn_face_module_init (vlib_main_t *vm);

u8 *format_hicn_face (u8 *s, va_list *args);

/**
 * @brief Format all the existing faces
 *
 * @param s Pointer to a previous string. If null it will be initialize
 * @param n Number of input parameters
 * @return String with the faces formatted
 */
u8 *format_hicn_face_all (u8 *s, int n, ...);

/**
 * @bried vector of faces used to collect faces having the same local address
 *
 */
typedef hicn_face_id_t *hicn_face_vec_t;

typedef struct hicn_input_faces_s_
{
  /* Vector of all possible input faces */
  u32 vec_id;

  /* Preferred face. If an prod_app face is in the vector it will be the
   * preferred one. */
  /* It's not possible to have multiple prod_app face in the same vector, they
   * would have */
  /* the same local address. Every prod_app face is a point-to-point face
   * between the forwarder */
  /* and the application. */
  hicn_face_id_t face_id;

} hicn_face_input_faces_t;

/**
 * Key definition for the mhash table. An face is uniquely identified by ip
 * address, the interface id and a dpo pointing to the next node in the vlib
 * graph. The ip address can correspond to the remote ip address of the next
 * hicn hop, or to the local address of the receiving interface. The former is
 * used to retrieve the incoming face when an interest is received, the latter
 * when the arring packet is a data. If the face is a regular face In case of
 * iface, the following structure can be filled in different ways:
 * - dpo equal to DPO_INVALID when the iface is a regular hICN iface
 * - in case of udp_tunnel dpo =
 *   {
 *    .dpoi_index = tunnel_id,
 *    .dpoi_type = DPO_FIRST,  //We don't need the type, we leave it invalid
 *    .dpoi_proto = DPO_PROTO_IP4 or DPO_PROTO_IP6,
 *    .dpoi_next_node = HICN6_IFACE_OUTPUT_NEXT_UDP4_ENCAP or
 *                      HICN6_IFACE_OUTPUT_NEXT_UDP6_ENCAP or
 *                      HICN4_IFACE_OUTPUT_NEXT_UDP4_ENCAP or
 *                      HICN4_IFACE_OUTPUT_NEXT_UDP6_ENCAP
 *    }
 */
typedef struct __attribute__ ((packed)) hicn_face_key_s
{
  ip46_address_t addr;
  union
  {
    dpo_id_t dpo;
    u64 align_dpo;
  };
  u32 sw_if;
} hicn_face_key_t;

/**
 * @brief Create the key object for the mhash. Fill in the key object with the
 * expected values.
 *
 * @param addr nat address of the face
 * @param sw_if interface associated to the face
 * @param key Pointer to an allocated hicn_face_ip_key_t object
 */
always_inline void
hicn_face_get_key (const ip46_address_t *addr, u32 sw_if, const dpo_id_t *dpo,
		   hicn_face_key_t *key)
{
  key->dpo = *dpo;
  key->addr = *addr;
  key->sw_if = sw_if;
}

/**
 * @brief Get the face obj from the nat address. Does not add any lock.
 *
 * @param addr Ip v4 address used to create the key for the hash table.
 * @param sw_if Software interface id used to create the key for the hash
 * table.
 * @param hashtb Hash table (remote or local) where to perform the lookup.
 *
 * @result Pointer to the face.
 */
always_inline hicn_face_t *
hicn_face_get (const ip46_address_t *addr, u32 sw_if, mhash_t *hashtb,
	       index_t adj_index)
{
  hicn_face_key_t key;

  dpo_id_t dpo = DPO_INVALID;

  dpo.dpoi_index = adj_index;

  hicn_face_get_key (addr, sw_if, &dpo, &key);

  hicn_face_id_t *dpoi_index = (hicn_face_id_t *) mhash_get (hashtb, &key);

  if (dpoi_index != NULL && hicn_dpoi_idx_is_valid (*dpoi_index))
    {
      hicn_face_lock_with_id (*dpoi_index);
      return hicn_dpoi_get_from_idx (*dpoi_index);
    }

  return NULL;
}

/**
 * @brief Get the face obj from the nat address and the dpo. Does not add any
 * lock.
 *
 * @param addr Ip v4 address used to create the key for the hash table.
 * @param sw_if Software interface id used to create the key for the hash
 * table.
 * @param hashtb Hash table (remote or local) where to perform the lookup.
 *
 * @result Pointer to the face.
 */
always_inline hicn_face_t *
hicn_face_get_with_dpo (const ip46_address_t *addr, u32 sw_if,
			const dpo_id_t *dpo, mhash_t *hashtb)
{
  hicn_face_key_t key;

  hicn_face_get_key (addr, sw_if, dpo, &key);

  hicn_face_id_t *dpoi_index = (hicn_face_id_t *) mhash_get (hashtb, &key);

  if (dpoi_index != NULL && hicn_dpoi_idx_is_valid (*dpoi_index))
    {
      hicn_face_lock_with_id (*dpoi_index);
      return hicn_dpoi_get_from_idx (*dpoi_index);
    }

  return NULL;
}

/**
 * @brief Create a new face ip. API for other modules (e.g., routing)
 *
 * @param dpo_nh dpo contained in the face that points to the next node in
 *        the vlib graph
 * @param nat_addr nat ip v4 or v6 address of the face
 * @param sw_if interface associated to the face
 * @param pfaceid Pointer to return the face id
 * @param is_app_prod if HICN_FACE_FLAGS_APPFACE_PROD the face is a local
 * application face, all other values are ignored
 * @return HICN_ERROR_FACE_NO_GLOBAL_IP if the face does not have a globally
 * reachable ip address, otherwise HICN_ERROR_NONE
 */
int hicn_face_add (const dpo_id_t *dpo_nh, ip46_address_t *nat_address,
		   int sw_if, hicn_face_id_t *pfaceid, dpo_proto_t dpo_proto);

/**
 * @brief Create a new incomplete face ip. (Meant to be used by the data plane)
 *
 * @param local_addr Local ip v4 or v6 address of the face
 * @param remote_addr Remote ip v4 or v6 address of the face
 * @param sw_if interface associated to the face
 * @param pfaceid Pointer to return the face id
 * @return HICN_ERROR_FACE_NO_GLOBAL_IP if the face does not have a globally
 * reachable ip address, otherwise HICN_ERROR_NONE
 */
always_inline void
hicn_iface_add (const ip46_address_t *nat_address, int sw_if,
		hicn_face_id_t *pfaceid, u32 adj_index, u8 flags)
{
  hicn_face_t *face;
  pool_get (hicn_dpoi_face_pool, face);

  clib_memcpy (&(face->nat_addr), nat_address, sizeof (ip46_address_t));
  face->sw_if = sw_if;

  face->dpo = (dpo_id_t) DPO_INVALID;
  face->dpo.dpoi_index = adj_index;

  hicn_face_key_t key;
  hicn_face_get_key (nat_address, sw_if, &face->dpo, &key);

  face->iface_next = 1;

  face->pl_id = pl_index++;
  face->flags = HICN_FACE_FLAGS_IFACE;
  face->flags |= flags;
  face->locks = 1;

  *pfaceid = hicn_dpoi_get_index (face);

  mhash_set_mem (&hicn_face_hashtb, &key, (uword *) pfaceid, 0);

  for (int i = 0; i < HICN_N_COUNTER; i++)
    {
      vlib_validate_combined_counter (&counters[(*pfaceid) * HICN_N_COUNTER],
				      i);
      vlib_zero_combined_counter (&counters[(*pfaceid) * HICN_N_COUNTER], i);
    }
}

/**** Helpers to manipulate faces and ifaces from the face/iface input nodes
 * ****/

/**
 * @brief Call back to get the adj of the tunnel
 */
static adj_walk_rc_t
hicn4_iface_adj_walk_cb (adj_index_t ai, void *ctx)
{

  hicn_face_t *face = (hicn_face_t *) ctx;

  dpo_set (&face->dpo, DPO_ADJACENCY_MIDCHAIN, DPO_PROTO_IP4, ai);
  adj_nbr_midchain_stack (ai, &face->dpo);

  return (ADJ_WALK_RC_CONTINUE);
}

always_inline int
hicn_face_ip4_find (hicn_face_id_t *index, u8 *hicnb_flags,
		    const ip4_address_t *nat_addr, u32 sw_if, u32 adj_index,
		    u32 node_index)
{
  int ret = HICN_ERROR_FACE_NOT_FOUND;
  hicn_face_id_t face_id;

  /*All (complete) faces are indexed by remote addess as well */
  /* if the face exists, it adds a lock */
  hicn_face_t *face = hicn_face_get ((const ip46_address_t *) nat_addr, sw_if,
				     &hicn_face_hashtb, adj_index);

  if (face != NULL)
    {
      /* unlock the face. We don't take a lock on each interest we receive */
      face_id = hicn_dpoi_get_index (face);
      hicn_face_unlock_with_id (face_id);

      *hicnb_flags = HICN_BUFFER_FLAGS_DEFAULT;
      *index = face_id;

      ret = HICN_ERROR_FACE_ALREADY_CREATED;
    }

  return ret;
}

/**
 * @brief Retrieve, or create if it doesn't exist, a face from the ip6 local
 * address and returns its dpo. This method adds a lock on the face state.
 *
 * @param dpo: Result of the lookup
 * @param hicnb_flags: Flags that indicate whether the face is an application
 * face or not
 * @param nat_addr: Ip v4 remote address of the face
 * @param sw_if: software interface id of the face
 * @param node_index: vlib edge index to use in the packet processing
 */
always_inline int
hicn_face_ip4_add_and_lock (hicn_face_id_t *index, u8 *hicnb_flags,
			    const ip4_address_t *nat_addr, u32 sw_if,
			    u32 adj_index, u32 node_index)
{
  int ret = HICN_ERROR_NONE;
  hicn_face_t *face = NULL;

  ret = hicn_face_ip4_find (index, hicnb_flags, nat_addr, sw_if, adj_index,
			    node_index);

  if (ret == HICN_ERROR_FACE_NOT_FOUND)
    {
      ip46_address_t ip_address = { 0 };
      ip46_address_set_ip4 (&ip_address, nat_addr);

      hicn_face_id_t idx;
      u8 face_flags = *hicnb_flags & HICN_BUFFER_FLAGS_FROM_UDP4_TUNNEL ?
			      HICN_FACE_FLAGS_UDP4 :
		      *hicnb_flags & HICN_BUFFER_FLAGS_FROM_UDP6_TUNNEL ?
			      HICN_FACE_FLAGS_UDP6 :
			      0;

      hicn_iface_add (&ip_address, sw_if, &idx, adj_index, face_flags);

      face = hicn_dpoi_get_from_idx (idx);

      face->iface_next = node_index;

      /* if (nat_addr->as_u32 == 0) */
      /*   { */
      adj_nbr_walk (face->sw_if, FIB_PROTOCOL_IP4, hicn4_iface_adj_walk_cb,
		    face);
      /* } */

      *hicnb_flags = HICN_BUFFER_FLAGS_DEFAULT;
      *hicnb_flags |= HICN_BUFFER_FLAGS_NEW_FACE;

      *index = idx;
    }

  return ret;
}

/**
 * @brief Call back to get the adj of the tunnel
 */
static adj_walk_rc_t
hicn6_iface_adj_walk_cb (adj_index_t ai, void *ctx)
{

  hicn_face_t *face = (hicn_face_t *) ctx;

  ip_adjacency_t *adj = adj_get (ai);
  if ((adj->lookup_next_index == IP_LOOKUP_NEXT_MIDCHAIN) ||
      (adj->lookup_next_index == IP_LOOKUP_NEXT_MCAST_MIDCHAIN))
    {
      dpo_set (&face->dpo, DPO_ADJACENCY_MIDCHAIN,
	       (dpo_proto_t) adj->ia_nh_proto, ai);
      adj_nbr_midchain_stack (ai, &face->dpo);
    }

  return (ADJ_WALK_RC_CONTINUE);
}

always_inline int
hicn_face_ip6_find (hicn_face_id_t *index, u8 *hicnb_flags,
		    const ip6_address_t *nat_addr, u32 sw_if, u32 adj_index,
		    u32 node_index)
{
  int ret = HICN_ERROR_FACE_NOT_FOUND;
  hicn_face_id_t face_id;

  hicn_face_t *face = hicn_face_get ((const ip46_address_t *) nat_addr, sw_if,
				     &hicn_face_hashtb, adj_index);

  if (face != NULL)
    {
      /* unlock the face. We don't take a lock on each interest we receive */
      face_id = hicn_dpoi_get_index (face);
      hicn_face_unlock_with_id (face_id);
      *hicnb_flags = HICN_BUFFER_FLAGS_DEFAULT;
      *index = face_id;

      ret = HICN_ERROR_FACE_ALREADY_CREATED;
    }

  return ret;
}

/**
 * @brief Retrieve, or create if it doesn't exist, a face from the ip6 local
 * address and returns its dpo. This method adds a lock on the face state.
 *
 * @param dpo: Result of the lookup
 * @param hicnb_flags: Flags that indicate whether the face is an application
 * face or not
 * @param nat_addr: Ip v6 remote address of the face
 * @param sw_if: software interface id of the face
 * @param node_index: vlib edge index to use in the packet processing
 */
always_inline int
hicn_face_ip6_add_and_lock (hicn_face_id_t *index, u8 *hicnb_flags,
			    const ip6_address_t *nat_addr, u32 sw_if,
			    u32 adj_index, u32 node_index)
{
  int ret = HICN_ERROR_NONE;
  hicn_face_t *face = NULL;

  ret = hicn_face_ip6_find (index, hicnb_flags, nat_addr, sw_if, adj_index,
			    node_index);

  if (ret == HICN_ERROR_FACE_NOT_FOUND)
    {
      ip46_address_t ip_address = { 0 };
      ip46_address_set_ip6 (&ip_address, nat_addr);
      hicn_face_id_t idx;
      u8 face_flags = *hicnb_flags & HICN_BUFFER_FLAGS_FROM_UDP4_TUNNEL ?
			      HICN_FACE_FLAGS_UDP4 :
		      *hicnb_flags & HICN_BUFFER_FLAGS_FROM_UDP6_TUNNEL ?
			      HICN_FACE_FLAGS_UDP6 :
			      0;

      hicn_iface_add ((const ip46_address_t *) nat_addr, sw_if, &idx,
		      adj_index, face_flags);

      face = hicn_dpoi_get_from_idx (idx);
      face->iface_next = node_index;

      adj_nbr_walk (face->sw_if, FIB_PROTOCOL_IP6, hicn6_iface_adj_walk_cb,
		    face);

      *hicnb_flags = HICN_BUFFER_FLAGS_NEW_FACE;
      *index = idx;
    }

  return ret;
}

/**
 * @brief Check if a face is an application face
 *
 * @param face_id: The id of the face
 * @return 1 if application face, 0 otherwise
 */
always_inline int
hicn_face_is_local (hicn_face_id_t face_id)
{
  hicn_face_t *face;
  face = hicn_dpoi_get_from_idx (face_id);
  ASSERT (face != NULL);

  return face->flags & HICN_FACE_FLAGS_APPFACE_PROD ||
	 face->flags & HICN_FACE_FLAGS_APPFACE_CONS;
}

#endif // __HICN_FACE_H__

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