aboutsummaryrefslogtreecommitdiffstats
path: root/src/vnet/ipsec/esp_decrypt.c
blob: c94577a5d5a4f3fcb1e0ba740a4caac5909dcb4d (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
/*
 * esp_decrypt.c : IPSec ESP decrypt node
 *
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <vnet/vnet.h>
#include <vnet/api_errno.h>
#include <vnet/ip/ip.h>

#include <vnet/ipsec/ipsec.h>
#include <vnet/ipsec/esp.h>
#include <vnet/ipsec/ipsec_io.h>

#define foreach_esp_decrypt_next                \
_(DROP, "error-drop")                           \
_(IP4_INPUT, "ip4-input-no-checksum")           \
_(IP6_INPUT, "ip6-input")                       \
_(IPSEC_GRE_INPUT, "ipsec-gre-input")

#define _(v, s) ESP_DECRYPT_NEXT_##v,
typedef enum
{
  foreach_esp_decrypt_next
#undef _
    ESP_DECRYPT_N_NEXT,
} esp_decrypt_next_t;


#define foreach_esp_decrypt_error                               \
 _(RX_PKTS, "ESP pkts received")                                \
 _(DECRYPTION_FAILED, "ESP decryption failed")                  \
 _(INTEG_ERROR, "Integrity check failed")                       \
 _(CRYPTO_ENGINE_ERROR, "crypto engine error (packet dropped)") \
 _(REPLAY, "SA replayed packet")                                \
 _(CHAINED_BUFFER, "chained buffers (packet dropped)")          \
 _(OVERSIZED_HEADER, "buffer with oversized header (dropped)")  \
 _(NO_TAIL_SPACE, "no enough buffer tail space (dropped)")


typedef enum
{
#define _(sym,str) ESP_DECRYPT_ERROR_##sym,
  foreach_esp_decrypt_error
#undef _
    ESP_DECRYPT_N_ERROR,
} esp_decrypt_error_t;

static char *esp_decrypt_error_strings[] = {
#define _(sym,string) string,
  foreach_esp_decrypt_error
#undef _
};

typedef struct
{
  u32 seq;
  ipsec_crypto_alg_t crypto_alg;
  ipsec_integ_alg_t integ_alg;
} esp_decrypt_trace_t;

/* packet trace format function */
static u8 *
format_esp_decrypt_trace (u8 * s, va_list * args)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *);

  s = format (s, "esp: crypto %U integrity %U seq %u",
	      format_ipsec_crypto_alg, t->crypto_alg,
	      format_ipsec_integ_alg, t->integ_alg, t->seq);
  return s;
}

typedef struct
{
  union
  {
    struct
    {
      u8 icv_sz;
      u8 iv_sz;
      ipsec_sa_flags_t flags:8;
      u32 sa_index;
    };
    u64 sa_data;
  };

  i16 current_data;
  i16 current_length;
  u16 hdr_sz;
} esp_decrypt_packet_data_t;

STATIC_ASSERT_SIZEOF (esp_decrypt_packet_data_t, 2 * sizeof (u64));

#define ESP_ENCRYPT_PD_F_FD_TRANSPORT (1 << 2)

always_inline uword
esp_decrypt_inline (vlib_main_t * vm,
		    vlib_node_runtime_t * node, vlib_frame_t * from_frame,
		    int is_ip6)
{
  ipsec_main_t *im = &ipsec_main;
  u32 thread_index = vm->thread_index;
  u16 buffer_data_size = vlib_buffer_get_default_data_size (vm);
  u16 len;
  ipsec_per_thread_data_t *ptd = vec_elt_at_index (im->ptd, thread_index);
  u32 *from = vlib_frame_vector_args (from_frame);
  u32 n, n_left = from_frame->n_vectors;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
  u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
  esp_decrypt_packet_data_t pkt_data[VLIB_FRAME_SIZE], *pd = pkt_data;
  esp_decrypt_packet_data_t cpd = { };
  u32 current_sa_index = ~0, current_sa_bytes = 0, current_sa_pkts = 0;
  const u8 esp_sz = sizeof (esp_header_t);
  ipsec_sa_t *sa0 = 0;

  vlib_get_buffers (vm, from, b, n_left);
  vec_reset_length (ptd->crypto_ops);
  vec_reset_length (ptd->integ_ops);
  clib_memset_u16 (nexts, -1, n_left);

  while (n_left > 0)
    {
      u8 *payload;

      if (n_left > 2)
	{
	  u8 *p;
	  vlib_prefetch_buffer_header (b[2], LOAD);
	  p = vlib_buffer_get_current (b[1]);
	  CLIB_PREFETCH (p, CLIB_CACHE_LINE_BYTES, LOAD);
	  p -= CLIB_CACHE_LINE_BYTES;
	  CLIB_PREFETCH (p, CLIB_CACHE_LINE_BYTES, LOAD);
	}

      if (vlib_buffer_chain_linearize (vm, b[0]) != 1)
	{
	  b[0]->error = node->errors[ESP_DECRYPT_ERROR_CHAINED_BUFFER];
	  next[0] = ESP_DECRYPT_NEXT_DROP;
	  goto next;
	}

      if (vnet_buffer (b[0])->ipsec.sad_index != current_sa_index)
	{
	  current_sa_index = vnet_buffer (b[0])->ipsec.sad_index;
	  sa0 = pool_elt_at_index (im->sad, current_sa_index);
	  cpd.icv_sz = sa0->integ_icv_size;
	  cpd.iv_sz = sa0->crypto_iv_size;
	  cpd.flags = sa0->flags;
	  cpd.sa_index = current_sa_index;

	  vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
					   current_sa_index, current_sa_pkts,
					   current_sa_bytes);

	  current_sa_bytes = current_sa_pkts = 0;
	}

      /* store packet data for next round for easier prefetch */
      pd->sa_data = cpd.sa_data;
      pd->current_data = b[0]->current_data;
      pd->current_length = b[0]->current_length;
      pd->hdr_sz = pd->current_data - vnet_buffer (b[0])->l3_hdr_offset;
      payload = b[0]->data + pd->current_data;

      /* we need 4 extra bytes for HMAC calculation when ESN are used */
      if (ipsec_sa_is_set_USE_ESN (sa0) && pd->icv_sz &&
	  (pd->current_data + pd->current_length + 4 > buffer_data_size))
	{
	  b[0]->error = node->errors[ESP_DECRYPT_ERROR_NO_TAIL_SPACE];
	  next[0] = ESP_DECRYPT_NEXT_DROP;
	  goto next;
	}

      /* anti-reply check */
      if (ipsec_sa_anti_replay_check (sa0, &((esp_header_t *) payload)->seq))
	{
	  b[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
	  next[0] = ESP_DECRYPT_NEXT_DROP;
	  goto next;
	}

      len = pd->current_length - cpd.icv_sz;
      current_sa_pkts += 1;
      current_sa_bytes += pd->current_length;

      if (PREDICT_TRUE (cpd.icv_sz > 0))
	{
	  vnet_crypto_op_t *op;
	  vec_add2_aligned (ptd->integ_ops, op, 1, CLIB_CACHE_LINE_BYTES);

	  vnet_crypto_op_init (op, sa0->integ_op_id);
	  op->key = sa0->integ_key.data;
	  op->key_len = sa0->integ_key.len;
	  op->src = payload;
	  op->flags = VNET_CRYPTO_OP_FLAG_HMAC_CHECK;
	  op->user_data = b - bufs;
	  op->digest = payload + len;
	  op->digest_len = cpd.icv_sz;
	  op->len = len;
	  if (ipsec_sa_is_set_USE_ESN (sa0))
	    {
	      /* shift ICV for 4 bytes to insert ESN */
	      u8 tmp[ESP_MAX_ICV_SIZE], sz = sizeof (sa0->seq_hi);
	      clib_memcpy_fast (tmp, payload + len, ESP_MAX_ICV_SIZE);
	      clib_memcpy_fast (payload + len, &sa0->seq_hi, sz);
	      clib_memcpy_fast (payload + len + sz, tmp, ESP_MAX_ICV_SIZE);
	      op->len += sz;
	      op->digest += sz;
	    }
	}

      payload += esp_sz;
      len -= esp_sz;

      if (sa0->crypto_enc_op_id != VNET_CRYPTO_OP_NONE)
	{
	  vnet_crypto_op_t *op;
	  vec_add2_aligned (ptd->crypto_ops, op, 1, CLIB_CACHE_LINE_BYTES);
	  vnet_crypto_op_init (op, sa0->crypto_dec_op_id);
	  op->key = sa0->crypto_key.data;
	  op->iv = payload;
	  op->src = op->dst = payload += cpd.iv_sz;
	  op->len = len - cpd.iv_sz;
	  op->user_data = b - bufs;
	}

      /* next */
    next:
      n_left -= 1;
      next += 1;
      pd += 1;
      b += 1;
    }

  vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
				   current_sa_index, current_sa_pkts,
				   current_sa_bytes);

  if ((n = vec_len (ptd->integ_ops)))
    {
      vnet_crypto_op_t *op = ptd->integ_ops;
      n -= vnet_crypto_process_ops (vm, op, n);
      while (n)
	{
	  ASSERT (op - ptd->integ_ops < vec_len (ptd->integ_ops));
	  if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
	    {
	      u32 err, bi = op->user_data;
	      if (op->status == VNET_CRYPTO_OP_STATUS_FAIL_BAD_HMAC)
		err = ESP_DECRYPT_ERROR_INTEG_ERROR;
	      else
		err = ESP_DECRYPT_ERROR_CRYPTO_ENGINE_ERROR;
	      bufs[bi]->error = node->errors[err];
	      nexts[bi] = ESP_DECRYPT_NEXT_DROP;
	      n--;
	    }
	  op++;
	}
    }
  if ((n = vec_len (ptd->crypto_ops)))
    {
      vnet_crypto_op_t *op = ptd->crypto_ops;
      n -= vnet_crypto_process_ops (vm, op, n);
      while (n)
	{
	  ASSERT (op - ptd->crypto_ops < vec_len (ptd->crypto_ops));
	  if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
	    {
	      u32 err, bi;

	      bi = op->user_data;

	      if (op->status == VNET_CRYPTO_OP_STATUS_FAIL_BAD_HMAC)
		err = ESP_DECRYPT_ERROR_DECRYPTION_FAILED;
	      else
		err = ESP_DECRYPT_ERROR_CRYPTO_ENGINE_ERROR;

	      bufs[bi]->error = node->errors[err];
	      nexts[bi] = ESP_DECRYPT_NEXT_DROP;
	      n--;
	    }
	  op++;
	}
    }

  /* Post decryption ronud - adjust packet data start and length and next
     node */

  n_left = from_frame->n_vectors;
  next = nexts;
  pd = pkt_data;
  b = bufs;

  while (n_left)
    {
      const u8 tun_flags = IPSEC_SA_FLAG_IS_TUNNEL |
	IPSEC_SA_FLAG_IS_TUNNEL_V6;

      if (n_left >= 2)
	{
	  void *data = b[1]->data + pd[1].current_data;

	  /* buffer metadata */
	  vlib_prefetch_buffer_header (b[1], LOAD);

	  /* esp_footer_t */
	  CLIB_PREFETCH (data + pd[1].current_length - pd[1].icv_sz - 2,
			 CLIB_CACHE_LINE_BYTES, LOAD);

	  /* packet headers */
	  CLIB_PREFETCH (data - CLIB_CACHE_LINE_BYTES,
			 CLIB_CACHE_LINE_BYTES * 2, LOAD);
	}

      if (next[0] < ESP_DECRYPT_N_NEXT)
	goto trace;

      sa0 = vec_elt_at_index (im->sad, pd->sa_index);
      u8 *payload = b[0]->data + pd->current_data;

      ipsec_sa_anti_replay_advance (sa0, &((esp_header_t *) payload)->seq);

      esp_footer_t *f = (esp_footer_t *) (b[0]->data + pd->current_data +
					  pd->current_length - sizeof (*f) -
					  pd->icv_sz);
      u16 adv = pd->iv_sz + esp_sz;
      u16 tail = sizeof (esp_footer_t) + f->pad_length + pd->icv_sz;

      if ((pd->flags & tun_flags) == 0)	/* transport mode */
	{
	  u8 udp_sz = (is_ip6 == 0 && pd->flags & IPSEC_SA_FLAG_UDP_ENCAP) ?
	    sizeof (udp_header_t) : 0;
	  u16 ip_hdr_sz = pd->hdr_sz - udp_sz;
	  u8 *old_ip = b[0]->data + pd->current_data - ip_hdr_sz - udp_sz;
	  u8 *ip = old_ip + adv + udp_sz;

	  if (is_ip6 && ip_hdr_sz > 64)
	    memmove (ip, old_ip, ip_hdr_sz);
	  else
	    clib_memcpy_le64 (ip, old_ip, ip_hdr_sz);

	  b[0]->current_data = pd->current_data + adv - ip_hdr_sz;
	  b[0]->current_length = pd->current_length + ip_hdr_sz - tail - adv;

	  if (is_ip6)
	    {
	      ip6_header_t *ip6 = (ip6_header_t *) ip;
	      u16 len = clib_net_to_host_u16 (ip6->payload_length);
	      len -= adv + tail;
	      ip6->payload_length = clib_host_to_net_u16 (len);
	      ip6->protocol = f->next_header;
	      next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
	    }
	  else
	    {
	      ip4_header_t *ip4 = (ip4_header_t *) ip;
	      ip_csum_t sum = ip4->checksum;
	      u16 len = clib_net_to_host_u16 (ip4->length);
	      len = clib_host_to_net_u16 (len - adv - tail - udp_sz);
	      sum = ip_csum_update (sum, ip4->protocol, f->next_header,
				    ip4_header_t, protocol);
	      sum = ip_csum_update (sum, ip4->length, len,
				    ip4_header_t, length);
	      ip4->checksum = ip_csum_fold (sum);
	      ip4->protocol = f->next_header;
	      ip4->length = len;
	      next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
	    }
	}
      else
	{
	  if (PREDICT_TRUE (f->next_header == IP_PROTOCOL_IP_IN_IP))
	    {
	      next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
	      b[0]->current_data = pd->current_data + adv;
	      b[0]->current_length = pd->current_length + adv - tail;
	    }
	  else if (f->next_header == IP_PROTOCOL_IPV6)
	    {
	      next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
	      b[0]->current_data = pd->current_data + adv;
	      b[0]->current_length = pd->current_length + adv - tail;
	    }
	  else
	    {
	      next[0] = ESP_DECRYPT_NEXT_DROP;
	      b[0]->error = node->errors[ESP_DECRYPT_ERROR_DECRYPTION_FAILED];
	    }
	}

      if (PREDICT_FALSE (ipsec_sa_is_set_IS_GRE (sa0)))
	next[0] = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;

    trace:
      if (PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
	{
	  esp_decrypt_trace_t *tr;
	  u8 *payload = b[0]->data + pd->current_data;
	  tr = vlib_add_trace (vm, node, b[0], sizeof (*tr));
	  sa0 = pool_elt_at_index (im->sad,
				   vnet_buffer (b[0])->ipsec.sad_index);
	  tr->crypto_alg = sa0->crypto_alg;
	  tr->integ_alg = sa0->integ_alg;
	  tr->seq = clib_host_to_net_u32 (((esp_header_t *) payload)->seq);
	}

      /* next */
      n_left -= 1;
      next += 1;
      pd += 1;
      b += 1;
    }

  n_left = from_frame->n_vectors;
  vlib_node_increment_counter (vm, node->node_index,
			       ESP_DECRYPT_ERROR_RX_PKTS, n_left);

  vlib_buffer_enqueue_to_next (vm, node, from, nexts, n_left);

  b = bufs;
  return n_left;
}

VLIB_NODE_FN (esp4_decrypt_node) (vlib_main_t * vm,
				  vlib_node_runtime_t * node,
				  vlib_frame_t * from_frame)
{
  return esp_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (esp4_decrypt_node) = {
  .name = "esp4-decrypt",
  .vector_size = sizeof (u32),
  .format_trace = format_esp_decrypt_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
  .error_strings = esp_decrypt_error_strings,

  .n_next_nodes = ESP_DECRYPT_N_NEXT,
  .next_nodes = {
#define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
    foreach_esp_decrypt_next
#undef _
  },
};
/* *INDENT-ON* */

VLIB_NODE_FN (esp6_decrypt_node) (vlib_main_t * vm,
				  vlib_node_runtime_t * node,
				  vlib_frame_t * from_frame)
{
  return esp_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (esp6_decrypt_node) = {
  .name = "esp6-decrypt",
  .vector_size = sizeof (u32),
  .format_trace = format_esp_decrypt_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
  .error_strings = esp_decrypt_error_strings,

  .n_next_nodes = ESP_DECRYPT_N_NEXT,
  .next_nodes = {
#define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
    foreach_esp_decrypt_next
#undef _
  },
};
/* *INDENT-ON* */

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