vnet/vnet/ipsec/esp_encrypt.c

   1 /*
   2  * esp_encrypt.c : IPSec ESP encrypt node
   3  *
   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:
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  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.
  16  */
  17
  18 #include <vnet/vnet.h>
  19 #include <vnet/api_errno.h>
  20 #include <vnet/ip/ip.h>
  21
  22 #include <vnet/ipsec/ipsec.h>
  23 #include <vnet/ipsec/esp.h>
  24
  25 #define ESP_SEQ_MAX (4294967295UL)
  26
  27 #define foreach_esp_encrypt_next                   \
  28 _(DROP, "error-drop")                              \
  29 _(IP4_INPUT, "ip4-input")                          \
  30 _(IP6_INPUT, "ip6-input")                          \
  31 _(INTERFACE_OUTPUT, "interface-output")
  32
  33 #define _(v, s) ESP_ENCRYPT_NEXT_##v,
  34 typedef enum
  35 {
  36   foreach_esp_encrypt_next
  37 #undef _
  38     ESP_ENCRYPT_N_NEXT,
  39 } esp_encrypt_next_t;
  40
  41 #define foreach_esp_encrypt_error                   \
  42  _(RX_PKTS, "ESP pkts received")                    \
  43  _(NO_BUFFER, "No buffer (packet dropped)")         \
  44  _(DECRYPTION_FAILED, "ESP encryption failed")      \
  45  _(SEQ_CYCLED, "sequence number cycled")
  46
  47
  48 typedef enum
  49 {
  50 #define _(sym,str) ESP_ENCRYPT_ERROR_##sym,
  51   foreach_esp_encrypt_error
  52 #undef _
  53     ESP_ENCRYPT_N_ERROR,
  54 } esp_encrypt_error_t;
  55
  56 static char *esp_encrypt_error_strings[] = {
  57 #define _(sym,string) string,
  58   foreach_esp_encrypt_error
  59 #undef _
  60 };
  61
  62 vlib_node_registration_t esp_encrypt_node;
  63
  64 typedef struct
  65 {
  66   u32 spi;
  67   u32 seq;
  68   ipsec_crypto_alg_t crypto_alg;
  69   ipsec_integ_alg_t integ_alg;
  70 } esp_encrypt_trace_t;
  71
  72 /* packet trace format function */
  73 static u8 *
  74 format_esp_encrypt_trace (u8 * s, va_list * args)
  75 {
  76   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  77   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  78   esp_encrypt_trace_t *t = va_arg (*args, esp_encrypt_trace_t *);
  79
  80   s = format (s, "esp: spi %u seq %u crypto %U integrity %U",
  81               t->spi, t->seq,
  82               format_ipsec_crypto_alg, t->crypto_alg,
  83               format_ipsec_integ_alg, t->integ_alg);
  84   return s;
  85 }
  86
  87 always_inline void
  88 esp_encrypt_aes_cbc (ipsec_crypto_alg_t alg,
  89                      u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
  90 {
  91   esp_main_t *em = &esp_main;
  92   u32 cpu_index = os_get_cpu_number ();
  93   EVP_CIPHER_CTX *ctx = &(em->per_thread_data[cpu_index].encrypt_ctx);
  94   const EVP_CIPHER *cipher = NULL;
  95   int out_len;
  96
  97   ASSERT (alg < IPSEC_CRYPTO_N_ALG);
  98
  99   if (PREDICT_FALSE (em->esp_crypto_algs[alg].type == IPSEC_CRYPTO_ALG_NONE))
 100     return;
 101
 102   if (PREDICT_FALSE (alg != em->per_thread_data[cpu_index].last_encrypt_alg))
 103     {
 104       cipher = em->esp_crypto_algs[alg].type;
 105       em->per_thread_data[cpu_index].last_encrypt_alg = alg;
 106     }
 107
 108   EVP_EncryptInit_ex (ctx, cipher, NULL, key, iv);
 109
 110   EVP_EncryptUpdate (ctx, out, &out_len, in, in_len);
 111   EVP_EncryptFinal_ex (ctx, out + out_len, &out_len);
 112 }
 113
 114 always_inline int
 115 esp_seq_advance (ipsec_sa_t * sa)
 116 {
 117   if (PREDICT_TRUE (sa->use_esn))
 118     {
 119       if (PREDICT_FALSE (sa->seq == ESP_SEQ_MAX))
 120         {
 121           if (PREDICT_FALSE
 122               (sa->use_anti_replay && sa->seq_hi == ESP_SEQ_MAX))
 123             return 1;
 124           sa->seq_hi++;
 125         }
 126       sa->seq++;
 127     }
 128   else
 129     {
 130       if (PREDICT_FALSE (sa->use_anti_replay && sa->seq == ESP_SEQ_MAX))
 131         return 1;
 132       sa->seq++;
 133     }
 134
 135   return 0;
 136 }
 137
 138 static uword
 139 esp_encrypt_node_fn (vlib_main_t * vm,
 140                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 141 {
 142   u32 n_left_from, *from, *to_next = 0, next_index;
 143   from = vlib_frame_vector_args (from_frame);
 144   n_left_from = from_frame->n_vectors;
 145   ipsec_main_t *im = &ipsec_main;
 146   u32 *recycle = 0;
 147   u32 cpu_index = os_get_cpu_number ();
 148
 149   ipsec_alloc_empty_buffers (vm, im);
 150
 151   u32 *empty_buffers = im->empty_buffers[cpu_index];
 152
 153   if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
 154     {
 155       vlib_node_increment_counter (vm, esp_encrypt_node.index,
 156                                    ESP_ENCRYPT_ERROR_NO_BUFFER, n_left_from);
 157       clib_warning ("no enough empty buffers. discarding frame");
 158       goto free_buffers_and_exit;
 159     }
 160
 161   next_index = node->cached_next_index;
 162
 163   while (n_left_from > 0)
 164     {
 165       u32 n_left_to_next;
 166
 167       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 168
 169       while (n_left_from > 0 && n_left_to_next > 0)
 170         {
 171           u32 i_bi0, o_bi0, next0;
 172           vlib_buffer_t *i_b0, *o_b0 = 0;
 173           u32 sa_index0;
 174           ipsec_sa_t *sa0;
 175           ip4_and_esp_header_t *ih0, *oh0 = 0;
 176           ip6_and_esp_header_t *ih6_0, *oh6_0 = 0;
 177           uword last_empty_buffer;
 178           esp_header_t *o_esp0;
 179           esp_footer_t *f0;
 180           u8 is_ipv6;
 181           u8 ip_hdr_size;
 182           u8 next_hdr_type;
 183           u32 ip_proto = 0;
 184           u8 transport_mode = 0;
 185
 186           i_bi0 = from[0];
 187           from += 1;
 188           n_left_from -= 1;
 189           n_left_to_next -= 1;
 190
 191           next0 = ESP_ENCRYPT_NEXT_DROP;
 192
 193           i_b0 = vlib_get_buffer (vm, i_bi0);
 194           sa_index0 = vnet_buffer (i_b0)->output_features.ipsec_sad_index;
 195           sa0 = pool_elt_at_index (im->sad, sa_index0);
 196
 197           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 198             {
 199               clib_warning ("sequence number counter has cycled SPI %u",
 200                             sa0->spi);
 201               vlib_node_increment_counter (vm, esp_encrypt_node.index,
 202                                            ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 203               //TODO: rekey SA
 204               o_bi0 = i_bi0;
 205               goto trace;
 206             }
 207
 208           /* grab free buffer */
 209           last_empty_buffer = vec_len (empty_buffers) - 1;
 210           o_bi0 = empty_buffers[last_empty_buffer];
 211           o_b0 = vlib_get_buffer (vm, o_bi0);
 212           o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 213           o_b0->current_data = sizeof (ethernet_header_t);
 214           ih0 = vlib_buffer_get_current (i_b0);
 215           vlib_prefetch_buffer_with_index (vm,
 216                                            empty_buffers[last_empty_buffer -
 217                                                          1], STORE);
 218           _vec_len (empty_buffers) = last_empty_buffer;
 219           to_next[0] = o_bi0;
 220           to_next += 1;
 221
 222           /* add old buffer to the recycle list */
 223           vec_add1 (recycle, i_bi0);
 224
 225           /* is ipv6 */
 226           if (PREDICT_FALSE
 227               ((ih0->ip4.ip_version_and_header_length & 0xF0) == 0x60))
 228             {
 229               is_ipv6 = 1;
 230               ih6_0 = vlib_buffer_get_current (i_b0);
 231               ip_hdr_size = sizeof (ip6_header_t);
 232               next_hdr_type = IP_PROTOCOL_IPV6;
 233               oh6_0 = vlib_buffer_get_current (o_b0);
 234               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof (ip6_header_t);
 235
 236               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 237                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 238               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 239               oh6_0->ip6.hop_limit = 254;
 240               oh6_0->ip6.src_address.as_u64[0] =
 241                 ih6_0->ip6.src_address.as_u64[0];
 242               oh6_0->ip6.src_address.as_u64[1] =
 243                 ih6_0->ip6.src_address.as_u64[1];
 244               oh6_0->ip6.dst_address.as_u64[0] =
 245                 ih6_0->ip6.dst_address.as_u64[0];
 246               oh6_0->ip6.dst_address.as_u64[1] =
 247                 ih6_0->ip6.dst_address.as_u64[1];
 248               oh6_0->esp.spi = clib_net_to_host_u32 (sa0->spi);
 249               oh6_0->esp.seq = clib_net_to_host_u32 (sa0->seq);
 250               ip_proto = ih6_0->ip6.protocol;
 251             }
 252           else
 253             {
 254               is_ipv6 = 0;
 255               ip_hdr_size = sizeof (ip4_header_t);
 256               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 257               oh0 = vlib_buffer_get_current (o_b0);
 258               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof (ip4_header_t);
 259
 260               oh0->ip4.ip_version_and_header_length = 0x45;
 261               oh0->ip4.tos = ih0->ip4.tos;
 262               oh0->ip4.fragment_id = 0;
 263               oh0->ip4.flags_and_fragment_offset = 0;
 264               oh0->ip4.ttl = 254;
 265               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 266               oh0->ip4.src_address.as_u32 = ih0->ip4.src_address.as_u32;
 267               oh0->ip4.dst_address.as_u32 = ih0->ip4.dst_address.as_u32;
 268               oh0->esp.spi = clib_net_to_host_u32 (sa0->spi);
 269               oh0->esp.seq = clib_net_to_host_u32 (sa0->seq);
 270               ip_proto = ih0->ip4.protocol;
 271             }
 272
 273           if (PREDICT_TRUE (sa0->is_tunnel && !sa0->is_tunnel_ip6))
 274             {
 275               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 276               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 277
 278               /* in tunnel mode send it back to FIB */
 279               next0 = ESP_ENCRYPT_NEXT_IP4_INPUT;
 280               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 281             }
 282           else if (sa0->is_tunnel && sa0->is_tunnel_ip6)
 283             {
 284               oh6_0->ip6.src_address.as_u64[0] =
 285                 sa0->tunnel_src_addr.ip6.as_u64[0];
 286               oh6_0->ip6.src_address.as_u64[1] =
 287                 sa0->tunnel_src_addr.ip6.as_u64[1];
 288               oh6_0->ip6.dst_address.as_u64[0] =
 289                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 290               oh6_0->ip6.dst_address.as_u64[1] =
 291                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 292
 293               /* in tunnel mode send it back to FIB */
 294               next0 = ESP_ENCRYPT_NEXT_IP6_INPUT;
 295               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 296             }
 297           else
 298             {
 299               transport_mode = 1;
 300               ethernet_header_t *ieh0, *oeh0;
 301               ieh0 = (ethernet_header_t *) i_b0->data;
 302               oeh0 = (ethernet_header_t *) o_b0->data;
 303               clib_memcpy (oeh0, ieh0, sizeof (ethernet_header_t));
 304               vlib_buffer_advance (i_b0, ip_hdr_size);
 305               next_hdr_type = ip_proto;
 306               next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 307               o_b0->flags |= BUFFER_OUTPUT_FEAT_DONE;
 308               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 309                 vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 310               vnet_buffer (o_b0)->output_features.bitmap =
 311                 vnet_buffer (i_b0)->output_features.bitmap;
 312             }
 313
 314           ASSERT (sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 315
 316           if (PREDICT_TRUE (sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE))
 317             {
 318
 319               const int BLOCK_SIZE = 16;
 320               const int IV_SIZE = 16;
 321               int blocks = 1 + (i_b0->current_length + 1) / BLOCK_SIZE;
 322
 323               /* pad packet in input buffer */
 324               u8 pad_bytes = BLOCK_SIZE * blocks - 2 - i_b0->current_length;
 325               u8 i;
 326               u8 *padding =
 327                 vlib_buffer_get_current (i_b0) + i_b0->current_length;
 328               i_b0->current_length = BLOCK_SIZE * blocks;
 329               for (i = 0; i < pad_bytes; ++i)
 330                 {
 331                   padding[i] = i + 1;
 332                 }
 333               f0 = vlib_buffer_get_current (i_b0) + i_b0->current_length - 2;
 334               f0->pad_length = pad_bytes;
 335               f0->next_header = next_hdr_type;
 336
 337               o_b0->current_length = ip_hdr_size + sizeof (esp_header_t) +
 338                 BLOCK_SIZE * blocks + IV_SIZE;
 339
 340               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 341                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 342
 343               u8 iv[16];
 344               RAND_bytes (iv, sizeof (iv));
 345
 346               clib_memcpy ((u8 *) vlib_buffer_get_current (o_b0) +
 347                            ip_hdr_size + sizeof (esp_header_t), iv, 16);
 348
 349               esp_encrypt_aes_cbc (sa0->crypto_alg,
 350                                    (u8 *) vlib_buffer_get_current (i_b0),
 351                                    (u8 *) vlib_buffer_get_current (o_b0) +
 352                                    ip_hdr_size + sizeof (esp_header_t) +
 353                                    IV_SIZE, BLOCK_SIZE * blocks,
 354                                    sa0->crypto_key, iv);
 355             }
 356
 357           o_b0->current_length += hmac_calc (sa0->integ_alg, sa0->integ_key,
 358                                              sa0->integ_key_len,
 359                                              (u8 *) o_esp0,
 360                                              o_b0->current_length -
 361                                              ip_hdr_size,
 362                                              vlib_buffer_get_current (o_b0) +
 363                                              o_b0->current_length,
 364                                              sa0->use_esn, sa0->seq_hi);
 365
 366
 367           if (PREDICT_FALSE (is_ipv6))
 368             {
 369               oh6_0->ip6.payload_length =
 370                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0) -
 371                                       sizeof (ip6_header_t));
 372             }
 373           else
 374             {
 375               oh0->ip4.length =
 376                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0));
 377               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 378             }
 379
 380           if (transport_mode)
 381             vlib_buffer_reset (o_b0);
 382
 383         trace:
 384           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 385             {
 386               if (o_b0)
 387                 {
 388                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 389                   o_b0->trace_index = i_b0->trace_index;
 390                 }
 391               esp_encrypt_trace_t *tr =
 392                 vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 393               tr->spi = sa0->spi;
 394               tr->seq = sa0->seq - 1;
 395               tr->crypto_alg = sa0->crypto_alg;
 396               tr->integ_alg = sa0->integ_alg;
 397             }
 398
 399           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 400                                            to_next, n_left_to_next, o_bi0,
 401                                            next0);
 402         }
 403       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 404     }
 405   vlib_node_increment_counter (vm, esp_encrypt_node.index,
 406                                ESP_ENCRYPT_ERROR_RX_PKTS,
 407                                from_frame->n_vectors);
 408
 409 free_buffers_and_exit:
 410   vlib_buffer_free (vm, recycle, vec_len (recycle));
 411   vec_free (recycle);
 412   return from_frame->n_vectors;
 413 }
 414
 415
 416 /* *INDENT-OFF* */
 417 VLIB_REGISTER_NODE (esp_encrypt_node) = {
 418   .function = esp_encrypt_node_fn,
 419   .name = "esp-encrypt",
 420   .vector_size = sizeof (u32),
 421   .format_trace = format_esp_encrypt_trace,
 422   .type = VLIB_NODE_TYPE_INTERNAL,
 423
 424   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 425   .error_strings = esp_encrypt_error_strings,
 426
 427   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 428   .next_nodes = {
 429 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 430     foreach_esp_encrypt_next
 431 #undef _
 432   },
 433 };
 434 /* *INDENT-ON* */
 435
 436 VLIB_NODE_FUNCTION_MULTIARCH (esp_encrypt_node, esp_encrypt_node_fn)
 437 /*
 438  * fd.io coding-style-patch-verification: ON
 439  *
 440  * Local Variables:
 441  * eval: (c-set-style "gnu")
 442  * End:
 443  */