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")
49 #define _(sym,str) ESP_DECRYPT_ERROR_##sym,
50 foreach_esp_decrypt_error
53 } esp_decrypt_error_t;
55 static char * esp_decrypt_error_strings[] = {
56 #define _(sym,string) string,
57 foreach_esp_decrypt_error
62 ipsec_crypto_alg_t crypto_alg;
63 ipsec_integ_alg_t integ_alg;
64 } esp_decrypt_trace_t;
66 /* packet trace format function */
67 static u8 * format_esp_decrypt_trace (u8 * s, va_list * args)
69 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
70 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
71 esp_decrypt_trace_t * t = va_arg (*args, esp_decrypt_trace_t *);
73 s = format (s, "esp: crypto %U integrity %U",
74 format_ipsec_crypto_alg, t->crypto_alg,
75 format_ipsec_integ_alg, t->integ_alg);
80 esp_decrypt_aes_cbc(ipsec_crypto_alg_t alg,
87 esp_main_t * em = &esp_main;
88 u32 cpu_index = os_get_cpu_number();
89 EVP_CIPHER_CTX * ctx = &(em->per_thread_data[cpu_index].decrypt_ctx);
90 const EVP_CIPHER * cipher = NULL;
93 ASSERT(alg < IPSEC_CRYPTO_N_ALG);
95 if (PREDICT_FALSE(em->esp_crypto_algs[alg].type == 0))
98 if (PREDICT_FALSE(alg != em->per_thread_data[cpu_index].last_decrypt_alg)) {
99 cipher = em->esp_crypto_algs[alg].type;
100 em->per_thread_data[cpu_index].last_decrypt_alg = alg;
103 EVP_DecryptInit_ex(ctx, cipher, NULL, key, iv);
105 EVP_DecryptUpdate(ctx, out, &out_len, in, in_len);
106 EVP_DecryptFinal_ex(ctx, out + out_len, &out_len);
110 esp_replay_check (ipsec_sa_t * sa, u32 seq)
114 if (PREDICT_TRUE(seq > sa->last_seq))
117 diff = sa->last_seq - seq;
119 if (ESP_WINDOW_SIZE > diff)
120 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
128 esp_replay_check_esn (ipsec_sa_t * sa, u32 seq)
130 u32 tl = sa->last_seq;
131 u32 th = sa->last_seq_hi;
134 if (PREDICT_TRUE(tl >= (ESP_WINDOW_SIZE - 1)))
136 if (seq >= (tl - ESP_WINDOW_SIZE + 1))
140 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
152 if (seq >= (tl - ESP_WINDOW_SIZE + 1))
155 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
161 return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
171 esp_replay_advance (ipsec_sa_t * sa, u32 seq)
175 if (seq > sa->last_seq)
177 pos = seq - sa->last_seq;
178 if (pos < ESP_WINDOW_SIZE)
179 sa->replay_window = ((sa->replay_window) << pos) | 1;
181 sa->replay_window = 1;
186 pos = sa->last_seq - seq;
187 sa->replay_window |= (1ULL << pos);
192 esp_replay_advance_esn (ipsec_sa_t * sa, u32 seq)
194 int wrap = sa->seq_hi - sa->last_seq_hi;
197 if (wrap == 0 && seq > sa->last_seq)
199 pos = seq - sa->last_seq;
200 if (pos < ESP_WINDOW_SIZE)
201 sa->replay_window = ((sa->replay_window) << pos) | 1;
203 sa->replay_window = 1;
208 pos = ~seq + sa->last_seq + 1;
209 if (pos < ESP_WINDOW_SIZE)
210 sa->replay_window = ((sa->replay_window) << pos) | 1;
212 sa->replay_window = 1;
214 sa->last_seq_hi = sa->seq_hi;
218 pos = ~seq + sa->last_seq + 1;
219 sa->replay_window |= (1ULL << pos);
223 pos = sa->last_seq - seq;
224 sa->replay_window |= (1ULL << pos);
229 esp_decrypt_node_fn (vlib_main_t * vm,
230 vlib_node_runtime_t * node,
231 vlib_frame_t * from_frame)
233 u32 n_left_from, *from, next_index, *to_next;
234 ipsec_main_t *im = &ipsec_main;
235 esp_main_t *em = &esp_main;
237 from = vlib_frame_vector_args (from_frame);
238 n_left_from = from_frame->n_vectors;
239 u32 cpu_index = os_get_cpu_number();
240 u32 * empty_buffers = im->empty_buffers[cpu_index];
242 ipsec_alloc_empty_buffers(vm, im);
244 if (PREDICT_FALSE(vec_len (empty_buffers) < n_left_from)){
245 vlib_node_increment_counter (vm, esp_decrypt_node.index,
246 ESP_DECRYPT_ERROR_NO_BUFFER, n_left_from);
247 goto free_buffers_and_exit;
250 next_index = node->cached_next_index;
252 while (n_left_from > 0)
256 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
258 while (n_left_from > 0 && n_left_to_next > 0)
260 u32 i_bi0, o_bi0 = (u32) ~0, next0;
261 vlib_buffer_t * i_b0;
262 vlib_buffer_t * o_b0 = 0;
273 next0 = ESP_DECRYPT_NEXT_DROP;
275 i_b0 = vlib_get_buffer (vm, i_bi0);
276 esp0 = vlib_buffer_get_current (i_b0);
278 sa_index0 = vnet_buffer(i_b0)->output_features.ipsec_sad_index;
279 sa0 = pool_elt_at_index (im->sad, sa_index0);
281 seq = clib_host_to_net_u32(esp0->seq);
283 /* anti-replay check */
284 if (sa0->use_anti_replay)
288 if (PREDICT_TRUE(sa0->use_esn))
289 rv = esp_replay_check_esn(sa0, seq);
291 rv = esp_replay_check(sa0, seq);
293 if (PREDICT_FALSE(rv))
295 clib_warning("anti-replay SPI %u seq %u", sa0->spi, seq);
296 vlib_node_increment_counter (vm, esp_decrypt_node.index,
297 ESP_DECRYPT_ERROR_REPLAY, 1);
303 if (PREDICT_TRUE(sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
306 int icv_size = em->esp_integ_algs[sa0->integ_alg].trunc_size;
307 memset(sig, 0, sizeof(sig));
308 u8 * icv = vlib_buffer_get_current (i_b0) + i_b0->current_length - icv_size;
309 i_b0->current_length -= icv_size;
311 hmac_calc(sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
312 (u8 *) esp0, i_b0->current_length, sig, sa0->use_esn,
315 if (PREDICT_FALSE(memcmp(icv, sig, icv_size)))
317 vlib_node_increment_counter (vm, esp_decrypt_node.index,
318 ESP_DECRYPT_ERROR_INTEG_ERROR, 1);
324 if (PREDICT_TRUE(sa0->use_anti_replay))
326 if (PREDICT_TRUE(sa0->use_esn))
327 esp_replay_advance_esn(sa0, seq);
329 esp_replay_advance(sa0, seq);
332 /* grab free buffer */
333 uword last_empty_buffer = vec_len (empty_buffers) - 1;
334 o_bi0 = empty_buffers[last_empty_buffer];
335 o_b0 = vlib_get_buffer (vm, o_bi0);
336 vlib_prefetch_buffer_with_index (vm, empty_buffers[last_empty_buffer-1], STORE);
337 _vec_len (empty_buffers) = last_empty_buffer;
339 /* add old buffer to the recycle list */
340 vec_add1(recycle, i_bi0);
342 if (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
343 sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) {
344 const int BLOCK_SIZE = 16;
345 const int IV_SIZE = 16;
348 int blocks = (i_b0->current_length - sizeof (esp_header_t) - IV_SIZE) / BLOCK_SIZE;
350 o_b0->current_data = sizeof(ethernet_header_t);
352 esp_decrypt_aes_cbc(sa0->crypto_alg,
353 esp0->data + IV_SIZE,
354 (u8 *) vlib_buffer_get_current (o_b0),
359 o_b0->current_length = (blocks * 16) - 2;
360 o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
361 f0 = (esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) + o_b0->current_length);
362 o_b0->current_length -= f0->pad_length;
363 if (PREDICT_TRUE(f0->next_header == IP_PROTOCOL_IP_IN_IP))
364 next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
365 else if (f0->next_header == IP_PROTOCOL_IPV6)
366 next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
369 clib_warning("next header: 0x%x", f0->next_header);
370 vlib_node_increment_counter (vm, esp_decrypt_node.index,
371 ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
380 vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32)~0;
384 if (PREDICT_FALSE(i_b0->flags & VLIB_BUFFER_IS_TRACED)) {
386 o_b0->flags |= VLIB_BUFFER_IS_TRACED;
387 o_b0->trace_index = i_b0->trace_index;
389 esp_decrypt_trace_t *tr = vlib_add_trace (vm, node, o_b0, sizeof (*tr));
390 tr->crypto_alg = sa0->crypto_alg;
391 tr->integ_alg = sa0->integ_alg;
394 vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
395 n_left_to_next, o_bi0, next0);
397 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
399 vlib_node_increment_counter (vm, esp_decrypt_node.index,
400 ESP_DECRYPT_ERROR_RX_PKTS,
401 from_frame->n_vectors);
403 free_buffers_and_exit:
404 vlib_buffer_free (vm, recycle, vec_len(recycle));
406 return from_frame->n_vectors;
410 VLIB_REGISTER_NODE (esp_decrypt_node) = {
411 .function = esp_decrypt_node_fn,
412 .name = "esp-decrypt",
413 .vector_size = sizeof (u32),
414 .format_trace = format_esp_decrypt_trace,
415 .type = VLIB_NODE_TYPE_INTERNAL,
417 .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
418 .error_strings = esp_decrypt_error_strings,
420 .n_next_nodes = ESP_DECRYPT_N_NEXT,
422 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
423 foreach_esp_decrypt_next