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,
34 foreach_esp_decrypt_next
40 #define foreach_esp_decrypt_error \
41 _(RX_PKTS, "ESP pkts received") \
42 _(NO_BUFFER, "No buffer (packed dropped)") \
43 _(DECRYPTION_FAILED, "ESP decryption failed") \
44 _(INTEG_ERROR, "Integrity check failed") \
45 _(REPLAY, "SA replayed packet") \
46 _(NOT_IP, "Not IP packet (dropped)")
50 #define _(sym,str) ESP_DECRYPT_ERROR_##sym,
51 foreach_esp_decrypt_error
54 } esp_decrypt_error_t;
56 static char * esp_decrypt_error_strings[] = {
57 #define _(sym,string) string,
58 foreach_esp_decrypt_error
63 ipsec_crypto_alg_t crypto_alg;
64 ipsec_integ_alg_t integ_alg;
65 } esp_decrypt_trace_t;
67 /* packet trace format function */
68 static u8 * format_esp_decrypt_trace (u8 * s, va_list * args)
70 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
71 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
72 esp_decrypt_trace_t * t = va_arg (*args, esp_decrypt_trace_t *);
74 s = format (s, "esp: crypto %U integrity %U",
75 format_ipsec_crypto_alg, t->crypto_alg,
76 format_ipsec_integ_alg, t->integ_alg);
81 esp_decrypt_aes_cbc(ipsec_crypto_alg_t alg,
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)) {
100 cipher = em->esp_crypto_algs[alg].type;
101 em->per_thread_data[cpu_index].last_decrypt_alg = alg;
104 EVP_DecryptInit_ex(ctx, cipher, NULL, key, iv);
106 EVP_DecryptUpdate(ctx, out, &out_len, in, in_len);
107 EVP_DecryptFinal_ex(ctx, out + out_len, &out_len);
111 esp_replay_check (ipsec_sa_t * sa, u32 seq)
115 if (PREDICT_TRUE(seq > sa->last_seq))
118 diff = sa->last_seq - seq;
120 if (ESP_WINDOW_SIZE > diff)
121 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
129 esp_replay_check_esn (ipsec_sa_t * sa, u32 seq)
131 u32 tl = sa->last_seq;
132 u32 th = sa->last_seq_hi;
135 if (PREDICT_TRUE(tl >= (ESP_WINDOW_SIZE - 1)))
137 if (seq >= (tl - ESP_WINDOW_SIZE + 1))
141 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
153 if (seq >= (tl - ESP_WINDOW_SIZE + 1))
156 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
162 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
172 esp_replay_advance (ipsec_sa_t * sa, u32 seq)
176 if (seq > sa->last_seq)
178 pos = seq - sa->last_seq;
179 if (pos < ESP_WINDOW_SIZE)
180 sa->replay_window = ((sa->replay_window) << pos) | 1;
182 sa->replay_window = 1;
187 pos = sa->last_seq - seq;
188 sa->replay_window |= (1ULL << pos);
193 esp_replay_advance_esn (ipsec_sa_t * sa, u32 seq)
195 int wrap = sa->seq_hi - sa->last_seq_hi;
198 if (wrap == 0 && seq > sa->last_seq)
200 pos = seq - sa->last_seq;
201 if (pos < ESP_WINDOW_SIZE)
202 sa->replay_window = ((sa->replay_window) << pos) | 1;
204 sa->replay_window = 1;
209 pos = ~seq + sa->last_seq + 1;
210 if (pos < ESP_WINDOW_SIZE)
211 sa->replay_window = ((sa->replay_window) << pos) | 1;
213 sa->replay_window = 1;
215 sa->last_seq_hi = sa->seq_hi;
219 pos = ~seq + sa->last_seq + 1;
220 sa->replay_window |= (1ULL << pos);
224 pos = sa->last_seq - seq;
225 sa->replay_window |= (1ULL << pos);
230 esp_decrypt_node_fn (vlib_main_t * vm,
231 vlib_node_runtime_t * node,
232 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)){
247 vlib_node_increment_counter (vm, esp_decrypt_node.index,
248 ESP_DECRYPT_ERROR_NO_BUFFER, n_left_from);
249 goto free_buffers_and_exit;
252 next_index = node->cached_next_index;
254 while (n_left_from > 0)
258 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
260 while (n_left_from > 0 && n_left_to_next > 0)
262 u32 i_bi0, o_bi0 = (u32) ~0, next0;
263 vlib_buffer_t * i_b0;
264 vlib_buffer_t * o_b0 = 0;
269 ip4_header_t *ih4 = 0, *oh4 = 0;
270 ip6_header_t *ih6 = 0, *oh6 = 0;
272 u8 transport_ip6 = 0;
280 next0 = ESP_DECRYPT_NEXT_DROP;
282 i_b0 = vlib_get_buffer (vm, i_bi0);
283 esp0 = vlib_buffer_get_current (i_b0);
285 sa_index0 = vnet_buffer(i_b0)->output_features.ipsec_sad_index;
286 sa0 = pool_elt_at_index (im->sad, sa_index0);
288 seq = clib_host_to_net_u32(esp0->seq);
290 /* anti-replay check */
291 if (sa0->use_anti_replay)
295 if (PREDICT_TRUE(sa0->use_esn))
296 rv = esp_replay_check_esn(sa0, seq);
298 rv = esp_replay_check(sa0, seq);
300 if (PREDICT_FALSE(rv))
302 clib_warning("anti-replay SPI %u seq %u", sa0->spi, seq);
303 vlib_node_increment_counter (vm, esp_decrypt_node.index,
304 ESP_DECRYPT_ERROR_REPLAY, 1);
310 if (PREDICT_TRUE(sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
313 int icv_size = em->esp_integ_algs[sa0->integ_alg].trunc_size;
314 memset(sig, 0, sizeof(sig));
315 u8 * icv = vlib_buffer_get_current (i_b0) + i_b0->current_length - icv_size;
316 i_b0->current_length -= icv_size;
318 hmac_calc(sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
319 (u8 *) esp0, i_b0->current_length, sig, sa0->use_esn,
322 if (PREDICT_FALSE(memcmp(icv, sig, icv_size)))
324 vlib_node_increment_counter (vm, esp_decrypt_node.index,
325 ESP_DECRYPT_ERROR_INTEG_ERROR, 1);
331 if (PREDICT_TRUE(sa0->use_anti_replay))
333 if (PREDICT_TRUE(sa0->use_esn))
334 esp_replay_advance_esn(sa0, seq);
336 esp_replay_advance(sa0, seq);
339 /* grab free buffer */
340 uword last_empty_buffer = vec_len (empty_buffers) - 1;
341 o_bi0 = empty_buffers[last_empty_buffer];
342 o_b0 = vlib_get_buffer (vm, o_bi0);
343 vlib_prefetch_buffer_with_index (vm, empty_buffers[last_empty_buffer-1], STORE);
344 _vec_len (empty_buffers) = last_empty_buffer;
346 /* add old buffer to the recycle list */
347 vec_add1(recycle, i_bi0);
349 if (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
350 sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) {
351 const int BLOCK_SIZE = 16;
352 const int IV_SIZE = 16;
356 int blocks = (i_b0->current_length - sizeof (esp_header_t) - IV_SIZE) / BLOCK_SIZE;
358 o_b0->current_data = sizeof(ethernet_header_t);
361 if (PREDICT_FALSE(!sa0->is_tunnel && !sa0->is_tunnel_ip6))
364 ih4 = (ip4_header_t *) (i_b0->data + sizeof(ethernet_header_t));
365 if (PREDICT_TRUE((ih4->ip_version_and_header_length & 0xF0 ) != 0x40))
367 if (PREDICT_TRUE((ih4->ip_version_and_header_length & 0xF0 ) == 0x60))
370 ip_hdr_size = sizeof(ip6_header_t);
371 ih6 = (ip6_header_t *) (i_b0->data + sizeof(ethernet_header_t));
372 oh6 = vlib_buffer_get_current (o_b0);
376 vlib_node_increment_counter (vm, esp_decrypt_node.index,
377 ESP_DECRYPT_ERROR_NOT_IP,
385 oh4 = vlib_buffer_get_current (o_b0);
386 ip_hdr_size = sizeof(ip4_header_t);
390 esp_decrypt_aes_cbc(sa0->crypto_alg,
391 esp0->data + IV_SIZE,
392 (u8 *) vlib_buffer_get_current (o_b0) + ip_hdr_size,
397 o_b0->current_length = (blocks * 16) - 2 + ip_hdr_size;
398 o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
399 f0 = (esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) + o_b0->current_length);
400 o_b0->current_length -= f0->pad_length;
403 if (PREDICT_TRUE(tunnel_mode))
405 if (PREDICT_TRUE(f0->next_header == IP_PROTOCOL_IP_IN_IP))
406 next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
407 else if (f0->next_header == IP_PROTOCOL_IPV6)
408 next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
411 clib_warning("next header: 0x%x", f0->next_header);
412 vlib_node_increment_counter (vm, esp_decrypt_node.index,
413 ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
422 if (PREDICT_FALSE(transport_ip6))
424 next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
425 oh6->ip_version_traffic_class_and_flow_label =
426 ih6->ip_version_traffic_class_and_flow_label;
427 oh6->protocol = f0->next_header;
428 oh6->hop_limit = ih6->hop_limit;
429 oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
430 oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
431 oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
432 oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
433 oh6->payload_length = clib_host_to_net_u16 (
434 vlib_buffer_length_in_chain (vm, o_b0) - sizeof(ip6_header_t));
438 next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
439 oh4->ip_version_and_header_length = 0x45;
441 oh4->fragment_id = 0;
442 oh4->flags_and_fragment_offset = 0;
444 oh4->protocol = f0->next_header;
445 oh4->src_address.as_u32 = ih4->src_address.as_u32;
446 oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
447 oh4->length = clib_host_to_net_u16 (
448 vlib_buffer_length_in_chain (vm, o_b0));
449 oh4->checksum = ip4_header_checksum (oh4);
456 vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32)~0;
460 if (PREDICT_FALSE(i_b0->flags & VLIB_BUFFER_IS_TRACED)) {
462 o_b0->flags |= VLIB_BUFFER_IS_TRACED;
463 o_b0->trace_index = i_b0->trace_index;
465 esp_decrypt_trace_t *tr = vlib_add_trace (vm, node, o_b0, sizeof (*tr));
466 tr->crypto_alg = sa0->crypto_alg;
467 tr->integ_alg = sa0->integ_alg;
470 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
471 n_left_to_next, o_bi0, next0);
473 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
475 vlib_node_increment_counter (vm, esp_decrypt_node.index,
476 ESP_DECRYPT_ERROR_RX_PKTS,
477 from_frame->n_vectors);
479 free_buffers_and_exit:
480 vlib_buffer_free (vm, recycle, vec_len(recycle));
482 return from_frame->n_vectors;
486 VLIB_REGISTER_NODE (esp_decrypt_node) = {
487 .function = esp_decrypt_node_fn,
488 .name = "esp-decrypt",
489 .vector_size = sizeof (u32),
490 .format_trace = format_esp_decrypt_trace,
491 .type = VLIB_NODE_TYPE_INTERNAL,
493 .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
494 .error_strings = esp_decrypt_error_strings,
496 .n_next_nodes = ESP_DECRYPT_N_NEXT,
498 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
499 foreach_esp_decrypt_next
504 VLIB_NODE_FUNCTION_MULTIARCH (esp_decrypt_node, esp_decrypt_node_fn)