2 * esp_decrypt.c : IPSec ESP decrypt node
4 * Copyright (c) 2015 Cisco and/or its affiliates.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
18 #include <vnet/vnet.h>
19 #include <vnet/api_errno.h>
20 #include <vnet/ip/ip.h>
22 #include <vnet/ipsec/ipsec.h>
23 #include <vnet/ipsec/esp.h>
25 #define ESP_WINDOW_SIZE 64
27 #define foreach_esp_decrypt_next \
28 _(DROP, "error-drop") \
29 _(IP4_INPUT, "ip4-input") \
30 _(IP6_INPUT, "ip6-input")
32 #define _(v, s) ESP_DECRYPT_NEXT_##v,
35 foreach_esp_decrypt_next
41 #define foreach_esp_decrypt_error \
42 _(RX_PKTS, "ESP pkts received") \
43 _(NO_BUFFER, "No buffer (packed dropped)") \
44 _(DECRYPTION_FAILED, "ESP decryption failed") \
45 _(INTEG_ERROR, "Integrity check failed") \
46 _(REPLAY, "SA replayed packet") \
47 _(NOT_IP, "Not IP packet (dropped)")
52 #define _(sym,str) ESP_DECRYPT_ERROR_##sym,
53 foreach_esp_decrypt_error
56 } esp_decrypt_error_t;
58 static char *esp_decrypt_error_strings[] = {
59 #define _(sym,string) string,
60 foreach_esp_decrypt_error
66 ipsec_crypto_alg_t crypto_alg;
67 ipsec_integ_alg_t integ_alg;
68 } esp_decrypt_trace_t;
70 /* packet trace format function */
72 format_esp_decrypt_trace (u8 * s, va_list * args)
74 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
75 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
76 esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *);
78 s = format (s, "esp: crypto %U integrity %U",
79 format_ipsec_crypto_alg, t->crypto_alg,
80 format_ipsec_integ_alg, t->integ_alg);
85 esp_decrypt_aes_cbc (ipsec_crypto_alg_t alg,
86 u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
88 esp_main_t *em = &esp_main;
89 u32 cpu_index = os_get_cpu_number ();
90 EVP_CIPHER_CTX *ctx = &(em->per_thread_data[cpu_index].decrypt_ctx);
91 const EVP_CIPHER *cipher = NULL;
94 ASSERT (alg < IPSEC_CRYPTO_N_ALG);
96 if (PREDICT_FALSE (em->esp_crypto_algs[alg].type == 0))
99 if (PREDICT_FALSE (alg != em->per_thread_data[cpu_index].last_decrypt_alg))
101 cipher = em->esp_crypto_algs[alg].type;
102 em->per_thread_data[cpu_index].last_decrypt_alg = alg;
105 EVP_DecryptInit_ex (ctx, cipher, NULL, key, iv);
107 EVP_DecryptUpdate (ctx, out, &out_len, in, in_len);
108 EVP_DecryptFinal_ex (ctx, out + out_len, &out_len);
112 esp_replay_check (ipsec_sa_t * sa, u32 seq)
116 if (PREDICT_TRUE (seq > sa->last_seq))
119 diff = sa->last_seq - seq;
121 if (ESP_WINDOW_SIZE > diff)
122 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
130 esp_replay_check_esn (ipsec_sa_t * sa, u32 seq)
132 u32 tl = sa->last_seq;
133 u32 th = sa->last_seq_hi;
136 if (PREDICT_TRUE (tl >= (ESP_WINDOW_SIZE - 1)))
138 if (seq >= (tl - ESP_WINDOW_SIZE + 1))
142 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
154 if (seq >= (tl - ESP_WINDOW_SIZE + 1))
157 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
163 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
173 esp_replay_advance (ipsec_sa_t * sa, u32 seq)
177 if (seq > sa->last_seq)
179 pos = seq - sa->last_seq;
180 if (pos < ESP_WINDOW_SIZE)
181 sa->replay_window = ((sa->replay_window) << pos) | 1;
183 sa->replay_window = 1;
188 pos = sa->last_seq - seq;
189 sa->replay_window |= (1ULL << pos);
194 esp_replay_advance_esn (ipsec_sa_t * sa, u32 seq)
196 int wrap = sa->seq_hi - sa->last_seq_hi;
199 if (wrap == 0 && seq > sa->last_seq)
201 pos = seq - sa->last_seq;
202 if (pos < ESP_WINDOW_SIZE)
203 sa->replay_window = ((sa->replay_window) << pos) | 1;
205 sa->replay_window = 1;
210 pos = ~seq + sa->last_seq + 1;
211 if (pos < ESP_WINDOW_SIZE)
212 sa->replay_window = ((sa->replay_window) << pos) | 1;
214 sa->replay_window = 1;
216 sa->last_seq_hi = sa->seq_hi;
220 pos = ~seq + sa->last_seq + 1;
221 sa->replay_window |= (1ULL << pos);
225 pos = sa->last_seq - seq;
226 sa->replay_window |= (1ULL << pos);
231 esp_decrypt_node_fn (vlib_main_t * vm,
232 vlib_node_runtime_t * node, vlib_frame_t * from_frame)
234 u32 n_left_from, *from, next_index, *to_next;
235 ipsec_main_t *im = &ipsec_main;
236 esp_main_t *em = &esp_main;
238 from = vlib_frame_vector_args (from_frame);
239 n_left_from = from_frame->n_vectors;
240 u32 cpu_index = os_get_cpu_number ();
242 ipsec_alloc_empty_buffers (vm, im);
244 u32 *empty_buffers = im->empty_buffers[cpu_index];
246 if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
248 vlib_node_increment_counter (vm, esp_decrypt_node.index,
249 ESP_DECRYPT_ERROR_NO_BUFFER, n_left_from);
250 goto free_buffers_and_exit;
253 next_index = node->cached_next_index;
255 while (n_left_from > 0)
259 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
261 while (n_left_from > 0 && n_left_to_next > 0)
263 u32 i_bi0, o_bi0 = (u32) ~ 0, next0;
265 vlib_buffer_t *o_b0 = 0;
270 ip4_header_t *ih4 = 0, *oh4 = 0;
271 ip6_header_t *ih6 = 0, *oh6 = 0;
273 u8 transport_ip6 = 0;
281 next0 = ESP_DECRYPT_NEXT_DROP;
283 i_b0 = vlib_get_buffer (vm, i_bi0);
284 esp0 = vlib_buffer_get_current (i_b0);
286 sa_index0 = vnet_buffer (i_b0)->output_features.ipsec_sad_index;
287 sa0 = pool_elt_at_index (im->sad, sa_index0);
289 seq = clib_host_to_net_u32 (esp0->seq);
291 /* anti-replay check */
292 if (sa0->use_anti_replay)
296 if (PREDICT_TRUE (sa0->use_esn))
297 rv = esp_replay_check_esn (sa0, seq);
299 rv = esp_replay_check (sa0, seq);
301 if (PREDICT_FALSE (rv))
303 clib_warning ("anti-replay SPI %u seq %u", sa0->spi, seq);
304 vlib_node_increment_counter (vm, esp_decrypt_node.index,
305 ESP_DECRYPT_ERROR_REPLAY, 1);
311 if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
314 int icv_size = em->esp_integ_algs[sa0->integ_alg].trunc_size;
315 memset (sig, 0, sizeof (sig));
317 vlib_buffer_get_current (i_b0) + i_b0->current_length -
319 i_b0->current_length -= icv_size;
321 hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
322 (u8 *) esp0, i_b0->current_length, sig, sa0->use_esn,
325 if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
327 vlib_node_increment_counter (vm, esp_decrypt_node.index,
328 ESP_DECRYPT_ERROR_INTEG_ERROR,
335 if (PREDICT_TRUE (sa0->use_anti_replay))
337 if (PREDICT_TRUE (sa0->use_esn))
338 esp_replay_advance_esn (sa0, seq);
340 esp_replay_advance (sa0, seq);
343 /* grab free buffer */
344 uword last_empty_buffer = vec_len (empty_buffers) - 1;
345 o_bi0 = empty_buffers[last_empty_buffer];
346 o_b0 = vlib_get_buffer (vm, o_bi0);
347 vlib_prefetch_buffer_with_index (vm,
348 empty_buffers[last_empty_buffer -
350 _vec_len (empty_buffers) = last_empty_buffer;
352 /* add old buffer to the recycle list */
353 vec_add1 (recycle, i_bi0);
355 if (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
356 sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256)
358 const int BLOCK_SIZE = 16;
359 const int IV_SIZE = 16;
364 (i_b0->current_length - sizeof (esp_header_t) -
365 IV_SIZE) / BLOCK_SIZE;
367 o_b0->current_data = sizeof (ethernet_header_t);
370 if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
374 (ip4_header_t *) (i_b0->data +
375 sizeof (ethernet_header_t));
377 ((ih4->ip_version_and_header_length & 0xF0) != 0x40))
380 ((ih4->ip_version_and_header_length & 0xF0) ==
384 ip_hdr_size = sizeof (ip6_header_t);
386 (ip6_header_t *) (i_b0->data +
387 sizeof (ethernet_header_t));
388 oh6 = vlib_buffer_get_current (o_b0);
392 vlib_node_increment_counter (vm,
393 esp_decrypt_node.index,
394 ESP_DECRYPT_ERROR_NOT_IP,
402 oh4 = vlib_buffer_get_current (o_b0);
403 ip_hdr_size = sizeof (ip4_header_t);
407 esp_decrypt_aes_cbc (sa0->crypto_alg,
408 esp0->data + IV_SIZE,
409 (u8 *) vlib_buffer_get_current (o_b0) +
410 ip_hdr_size, BLOCK_SIZE * blocks,
411 sa0->crypto_key, esp0->data);
413 o_b0->current_length = (blocks * 16) - 2 + ip_hdr_size;
414 o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
416 (esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) +
417 o_b0->current_length);
418 o_b0->current_length -= f0->pad_length;
421 if (PREDICT_TRUE (tunnel_mode))
423 if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
424 next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
425 else if (f0->next_header == IP_PROTOCOL_IPV6)
426 next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
429 clib_warning ("next header: 0x%x", f0->next_header);
430 vlib_node_increment_counter (vm, esp_decrypt_node.index,
431 ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
440 if (PREDICT_FALSE (transport_ip6))
442 next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
443 oh6->ip_version_traffic_class_and_flow_label =
444 ih6->ip_version_traffic_class_and_flow_label;
445 oh6->protocol = f0->next_header;
446 oh6->hop_limit = ih6->hop_limit;
447 oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
448 oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
449 oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
450 oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
451 oh6->payload_length =
452 clib_host_to_net_u16 (vlib_buffer_length_in_chain
454 o_b0) - sizeof (ip6_header_t));
458 next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
459 oh4->ip_version_and_header_length = 0x45;
461 oh4->fragment_id = 0;
462 oh4->flags_and_fragment_offset = 0;
464 oh4->protocol = f0->next_header;
465 oh4->src_address.as_u32 = ih4->src_address.as_u32;
466 oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
468 clib_host_to_net_u16 (vlib_buffer_length_in_chain
470 oh4->checksum = ip4_header_checksum (oh4);
477 vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
481 if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
485 o_b0->flags |= VLIB_BUFFER_IS_TRACED;
486 o_b0->trace_index = i_b0->trace_index;
488 esp_decrypt_trace_t *tr =
489 vlib_add_trace (vm, node, o_b0, sizeof (*tr));
490 tr->crypto_alg = sa0->crypto_alg;
491 tr->integ_alg = sa0->integ_alg;
494 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
495 n_left_to_next, o_bi0, next0);
497 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
499 vlib_node_increment_counter (vm, esp_decrypt_node.index,
500 ESP_DECRYPT_ERROR_RX_PKTS,
501 from_frame->n_vectors);
503 free_buffers_and_exit:
504 vlib_buffer_free (vm, recycle, vec_len (recycle));
506 return from_frame->n_vectors;
511 VLIB_REGISTER_NODE (esp_decrypt_node) = {
512 .function = esp_decrypt_node_fn,
513 .name = "esp-decrypt",
514 .vector_size = sizeof (u32),
515 .format_trace = format_esp_decrypt_trace,
516 .type = VLIB_NODE_TYPE_INTERNAL,
518 .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
519 .error_strings = esp_decrypt_error_strings,
521 .n_next_nodes = ESP_DECRYPT_N_NEXT,
523 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
524 foreach_esp_decrypt_next
530 VLIB_NODE_FUNCTION_MULTIARCH (esp_decrypt_node, esp_decrypt_node_fn)
532 * fd.io coding-style-patch-verification: ON
535 * eval: (c-set-style "gnu")