src/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 #include <vnet/udp/udp.h>
  22
  23 #include <vnet/ipsec/ipsec.h>
  24 #include <vnet/ipsec/esp.h>
  25
  26 ipsec_proto_main_t ipsec_proto_main;
  27
  28 #define foreach_esp_encrypt_next                   \
  29 _(DROP, "error-drop")                              \
  30 _(IP4_LOOKUP, "ip4-lookup")                        \
  31 _(IP6_LOOKUP, "ip6-lookup")                        \
  32 _(INTERFACE_OUTPUT, "interface-output")
  33
  34 #define _(v, s) ESP_ENCRYPT_NEXT_##v,
  35 typedef enum
  36 {
  37   foreach_esp_encrypt_next
  38 #undef _
  39     ESP_ENCRYPT_N_NEXT,
  40 } esp_encrypt_next_t;
  41
  42 #define foreach_esp_encrypt_error                   \
  43  _(RX_PKTS, "ESP pkts received")                    \
  44  _(NO_BUFFER, "No buffer (packet dropped)")         \
  45  _(DECRYPTION_FAILED, "ESP encryption failed")      \
  46  _(SEQ_CYCLED, "sequence number cycled")
  47
  48
  49 typedef enum
  50 {
  51 #define _(sym,str) ESP_ENCRYPT_ERROR_##sym,
  52   foreach_esp_encrypt_error
  53 #undef _
  54     ESP_ENCRYPT_N_ERROR,
  55 } esp_encrypt_error_t;
  56
  57 static char *esp_encrypt_error_strings[] = {
  58 #define _(sym,string) string,
  59   foreach_esp_encrypt_error
  60 #undef _
  61 };
  62
  63 typedef struct
  64 {
  65   u32 spi;
  66   u32 seq;
  67   u8 udp_encap;
  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%s",
  81               t->spi, t->seq,
  82               format_ipsec_crypto_alg, t->crypto_alg,
  83               format_ipsec_integ_alg, t->integ_alg,
  84               t->udp_encap ? " udp-encap-enabled" : "");
  85   return s;
  86 }
  87
  88 always_inline void
  89 esp_encrypt_cbc (vlib_main_t * vm, ipsec_crypto_alg_t alg,
  90                  u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
  91 {
  92   ipsec_proto_main_t *em = &ipsec_proto_main;
  93   u32 thread_index = vm->thread_index;
  94 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
  95   EVP_CIPHER_CTX *ctx = em->per_thread_data[thread_index].encrypt_ctx;
  96 #else
  97   EVP_CIPHER_CTX *ctx = &(em->per_thread_data[thread_index].encrypt_ctx);
  98 #endif
  99   const EVP_CIPHER *cipher = NULL;
 100   int out_len;
 101
 102   ASSERT (alg < IPSEC_CRYPTO_N_ALG);
 103
 104   if (PREDICT_FALSE
 105       (em->ipsec_proto_main_crypto_algs[alg].type == IPSEC_CRYPTO_ALG_NONE))
 106     return;
 107
 108   if (PREDICT_FALSE
 109       (alg != em->per_thread_data[thread_index].last_encrypt_alg))
 110     {
 111       cipher = em->ipsec_proto_main_crypto_algs[alg].type;
 112       em->per_thread_data[thread_index].last_encrypt_alg = alg;
 113     }
 114
 115   EVP_EncryptInit_ex (ctx, cipher, NULL, key, iv);
 116
 117   EVP_EncryptUpdate (ctx, out, &out_len, in, in_len);
 118   EVP_EncryptFinal_ex (ctx, out + out_len, &out_len);
 119 }
 120
 121 always_inline uword
 122 esp_encrypt_inline (vlib_main_t * vm,
 123                     vlib_node_runtime_t * node, vlib_frame_t * from_frame,
 124                     int is_ip6)
 125 {
 126   u32 n_left_from, *from, *to_next = 0, next_index;
 127   from = vlib_frame_vector_args (from_frame);
 128   n_left_from = from_frame->n_vectors;
 129   ipsec_main_t *im = &ipsec_main;
 130   ipsec_proto_main_t *em = &ipsec_proto_main;
 131   u32 *recycle = 0;
 132   u32 thread_index = vm->thread_index;
 133
 134   ipsec_alloc_empty_buffers (vm, im);
 135
 136   u32 *empty_buffers = im->empty_buffers[thread_index];
 137
 138   if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
 139     {
 140       vlib_node_increment_counter (vm, node->node_index,
 141                                    ESP_ENCRYPT_ERROR_NO_BUFFER, n_left_from);
 142       clib_warning ("not enough empty buffers. discarding frame");
 143       goto free_buffers_and_exit;
 144     }
 145
 146   next_index = node->cached_next_index;
 147
 148   while (n_left_from > 0)
 149     {
 150       u32 n_left_to_next;
 151
 152       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 153
 154       while (n_left_from > 0 && n_left_to_next > 0)
 155         {
 156           u32 i_bi0, o_bi0, next0;
 157           vlib_buffer_t *i_b0, *o_b0 = 0;
 158           u32 sa_index0;
 159           ipsec_sa_t *sa0;
 160           ip4_and_esp_header_t *oh0 = 0;
 161           ip6_and_esp_header_t *ih6_0, *oh6_0 = 0;
 162           ip4_and_udp_and_esp_header_t *iuh0, *ouh0 = 0;
 163           uword last_empty_buffer;
 164           esp_header_t *o_esp0;
 165           esp_footer_t *f0;
 166           u8 ip_udp_hdr_size;
 167           u8 next_hdr_type;
 168           u32 ip_proto = 0;
 169           u8 transport_mode = 0;
 170
 171           i_bi0 = from[0];
 172           from += 1;
 173           n_left_from -= 1;
 174           n_left_to_next -= 1;
 175
 176           next0 = ESP_ENCRYPT_NEXT_DROP;
 177
 178           i_b0 = vlib_get_buffer (vm, i_bi0);
 179           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 180           sa0 = pool_elt_at_index (im->sad, sa_index0);
 181
 182           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 183             {
 184               clib_warning ("sequence number counter has cycled SPI %u",
 185                             sa0->spi);
 186               vlib_node_increment_counter (vm, node->node_index,
 187                                            ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 188               //TODO: rekey SA
 189               o_bi0 = i_bi0;
 190               to_next[0] = o_bi0;
 191               to_next += 1;
 192               goto trace;
 193             }
 194
 195           sa0->total_data_size += i_b0->current_length;
 196
 197           /* grab free buffer */
 198           last_empty_buffer = vec_len (empty_buffers) - 1;
 199           o_bi0 = empty_buffers[last_empty_buffer];
 200           o_b0 = vlib_get_buffer (vm, o_bi0);
 201           o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 202           o_b0->current_data = sizeof (ethernet_header_t);
 203           iuh0 = vlib_buffer_get_current (i_b0);
 204           vlib_prefetch_buffer_with_index (vm,
 205                                            empty_buffers[last_empty_buffer -
 206                                                          1], STORE);
 207           _vec_len (empty_buffers) = last_empty_buffer;
 208           to_next[0] = o_bi0;
 209           to_next += 1;
 210
 211           /* add old buffer to the recycle list */
 212           vec_add1 (recycle, i_bi0);
 213
 214           if (is_ip6)
 215             {
 216               ih6_0 = vlib_buffer_get_current (i_b0);
 217               next_hdr_type = IP_PROTOCOL_IPV6;
 218               oh6_0 = vlib_buffer_get_current (o_b0);
 219
 220               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 221                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 222               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 223               ip_udp_hdr_size = sizeof (ip6_header_t);
 224               o_esp0 = vlib_buffer_get_current (o_b0) + ip_udp_hdr_size;
 225               oh6_0->ip6.hop_limit = 254;
 226               oh6_0->ip6.src_address.as_u64[0] =
 227                 ih6_0->ip6.src_address.as_u64[0];
 228               oh6_0->ip6.src_address.as_u64[1] =
 229                 ih6_0->ip6.src_address.as_u64[1];
 230               oh6_0->ip6.dst_address.as_u64[0] =
 231                 ih6_0->ip6.dst_address.as_u64[0];
 232               oh6_0->ip6.dst_address.as_u64[1] =
 233                 ih6_0->ip6.dst_address.as_u64[1];
 234               o_esp0->spi = clib_net_to_host_u32 (sa0->spi);
 235               o_esp0->seq = clib_net_to_host_u32 (sa0->seq);
 236               ip_proto = ih6_0->ip6.protocol;
 237
 238               next0 = ESP_ENCRYPT_NEXT_IP6_LOOKUP;
 239             }
 240           else
 241             {
 242               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 243               oh0 = vlib_buffer_get_current (o_b0);
 244               ouh0 = vlib_buffer_get_current (o_b0);
 245
 246               oh0->ip4.ip_version_and_header_length = 0x45;
 247               oh0->ip4.tos = iuh0->ip4.tos;
 248               oh0->ip4.fragment_id = 0;
 249               oh0->ip4.flags_and_fragment_offset = 0;
 250               oh0->ip4.ttl = 254;
 251               if (sa0->udp_encap)
 252                 {
 253                   ouh0->udp.src_port =
 254                     clib_host_to_net_u16 (UDP_DST_PORT_ipsec);
 255                   ouh0->udp.dst_port =
 256                     clib_host_to_net_u16 (UDP_DST_PORT_ipsec);
 257                   ouh0->udp.checksum = 0;
 258                   ouh0->ip4.protocol = IP_PROTOCOL_UDP;
 259                   ip_udp_hdr_size =
 260                     sizeof (udp_header_t) + sizeof (ip4_header_t);
 261                 }
 262               else
 263                 {
 264                   oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 265                   ip_udp_hdr_size = sizeof (ip4_header_t);
 266                 }
 267               o_esp0 = vlib_buffer_get_current (o_b0) + ip_udp_hdr_size;
 268               oh0->ip4.src_address.as_u32 = iuh0->ip4.src_address.as_u32;
 269               oh0->ip4.dst_address.as_u32 = iuh0->ip4.dst_address.as_u32;
 270               o_esp0->spi = clib_net_to_host_u32 (sa0->spi);
 271               o_esp0->seq = clib_net_to_host_u32 (sa0->seq);
 272               ip_proto = iuh0->ip4.protocol;
 273
 274               next0 = ESP_ENCRYPT_NEXT_IP4_LOOKUP;
 275             }
 276
 277           if (PREDICT_TRUE (!is_ip6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 278             {
 279               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 280               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 281
 282               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = sa0->tx_fib_index;
 283             }
 284           else if (is_ip6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 285             {
 286               oh6_0->ip6.src_address.as_u64[0] =
 287                 sa0->tunnel_src_addr.ip6.as_u64[0];
 288               oh6_0->ip6.src_address.as_u64[1] =
 289                 sa0->tunnel_src_addr.ip6.as_u64[1];
 290               oh6_0->ip6.dst_address.as_u64[0] =
 291                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 292               oh6_0->ip6.dst_address.as_u64[1] =
 293                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 294
 295               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = sa0->tx_fib_index;
 296             }
 297           else
 298             {
 299               next_hdr_type = ip_proto;
 300               if (vnet_buffer (i_b0)->sw_if_index[VLIB_TX] != ~0)
 301                 {
 302                   transport_mode = 1;
 303                   ethernet_header_t *ieh0, *oeh0;
 304                   ieh0 =
 305                     (ethernet_header_t *) ((u8 *)
 306                                            vlib_buffer_get_current (i_b0) -
 307                                            sizeof (ethernet_header_t));
 308                   oeh0 = (ethernet_header_t *) o_b0->data;
 309                   clib_memcpy_fast (oeh0, ieh0, sizeof (ethernet_header_t));
 310                   next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 311                   vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 312                     vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 313                 }
 314
 315               if (is_ip6)
 316                 {
 317                   vlib_buffer_advance (i_b0, sizeof (ip6_header_t));
 318                 }
 319               else
 320                 {
 321                   vlib_buffer_advance (i_b0, sizeof (ip4_header_t));
 322                 }
 323             }
 324
 325           ASSERT (sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 326
 327           if (PREDICT_TRUE (sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE))
 328             {
 329
 330               const int BLOCK_SIZE =
 331                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;
 332               const int IV_SIZE =
 333                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
 334               int blocks = 1 + (i_b0->current_length + 1) / BLOCK_SIZE;
 335
 336               /* pad packet in input buffer */
 337               u8 pad_bytes = BLOCK_SIZE * blocks - 2 - i_b0->current_length;
 338               u8 i;
 339               u8 *padding =
 340                 vlib_buffer_get_current (i_b0) + i_b0->current_length;
 341               i_b0->current_length = BLOCK_SIZE * blocks;
 342               for (i = 0; i < pad_bytes; ++i)
 343                 {
 344                   padding[i] = i + 1;
 345                 }
 346               f0 = vlib_buffer_get_current (i_b0) + i_b0->current_length - 2;
 347               f0->pad_length = pad_bytes;
 348               f0->next_header = next_hdr_type;
 349
 350               o_b0->current_length = ip_udp_hdr_size + sizeof (esp_header_t) +
 351                 BLOCK_SIZE * blocks + IV_SIZE;
 352
 353               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 354                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 355
 356               u8 iv[em->
 357                     ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size];
 358               RAND_bytes (iv, sizeof (iv));
 359
 360               clib_memcpy_fast ((u8 *) vlib_buffer_get_current (o_b0) +
 361                                 ip_udp_hdr_size + sizeof (esp_header_t), iv,
 362                                 em->ipsec_proto_main_crypto_algs[sa0->
 363                                                                  crypto_alg].iv_size);
 364
 365               esp_encrypt_cbc (vm, sa0->crypto_alg,
 366                                (u8 *) vlib_buffer_get_current (i_b0),
 367                                (u8 *) vlib_buffer_get_current (o_b0) +
 368                                ip_udp_hdr_size + sizeof (esp_header_t) +
 369                                IV_SIZE, BLOCK_SIZE * blocks,
 370                                sa0->crypto_key, iv);
 371             }
 372
 373           o_b0->current_length += hmac_calc (sa0->integ_alg, sa0->integ_key,
 374                                              sa0->integ_key_len,
 375                                              (u8 *) o_esp0,
 376                                              o_b0->current_length -
 377                                              ip_udp_hdr_size,
 378                                              vlib_buffer_get_current (o_b0) +
 379                                              o_b0->current_length,
 380                                              sa0->use_esn, sa0->seq_hi);
 381
 382
 383           if (is_ip6)
 384             {
 385               oh6_0->ip6.payload_length =
 386                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0) -
 387                                       sizeof (ip6_header_t));
 388             }
 389           else
 390             {
 391               oh0->ip4.length =
 392                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0));
 393               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 394               if (sa0->udp_encap)
 395                 {
 396                   ouh0->udp.length =
 397                     clib_host_to_net_u16 (clib_net_to_host_u16
 398                                           (oh0->ip4.length) -
 399                                           ip4_header_bytes (&oh0->ip4));
 400                 }
 401             }
 402
 403           if (transport_mode)
 404             vlib_buffer_reset (o_b0);
 405
 406         trace:
 407           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 408             {
 409               if (o_b0)
 410                 {
 411                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 412                   o_b0->trace_index = i_b0->trace_index;
 413                   esp_encrypt_trace_t *tr =
 414                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 415                   tr->spi = sa0->spi;
 416                   tr->seq = sa0->seq - 1;
 417                   tr->udp_encap = sa0->udp_encap;
 418                   tr->crypto_alg = sa0->crypto_alg;
 419                   tr->integ_alg = sa0->integ_alg;
 420                 }
 421             }
 422
 423           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 424                                            to_next, n_left_to_next, o_bi0,
 425                                            next0);
 426         }
 427       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 428     }
 429   vlib_node_increment_counter (vm, node->node_index,
 430                                ESP_ENCRYPT_ERROR_RX_PKTS,
 431                                from_frame->n_vectors);
 432
 433 free_buffers_and_exit:
 434   if (recycle)
 435     vlib_buffer_free (vm, recycle, vec_len (recycle));
 436   vec_free (recycle);
 437   return from_frame->n_vectors;
 438 }
 439
 440 VLIB_NODE_FN (esp4_encrypt_node) (vlib_main_t * vm,
 441                                   vlib_node_runtime_t * node,
 442                                   vlib_frame_t * from_frame)
 443 {
 444   return esp_encrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 445 }
 446
 447 /* *INDENT-OFF* */
 448 VLIB_REGISTER_NODE (esp4_encrypt_node) = {
 449   .name = "esp4-encrypt",
 450   .vector_size = sizeof (u32),
 451   .format_trace = format_esp_encrypt_trace,
 452   .type = VLIB_NODE_TYPE_INTERNAL,
 453
 454   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 455   .error_strings = esp_encrypt_error_strings,
 456
 457   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 458   .next_nodes = {
 459 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 460     foreach_esp_encrypt_next
 461 #undef _
 462   },
 463 };
 464 /* *INDENT-ON* */
 465
 466 VLIB_NODE_FN (esp6_encrypt_node) (vlib_main_t * vm,
 467                                   vlib_node_runtime_t * node,
 468                                   vlib_frame_t * from_frame)
 469 {
 470   return esp_encrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 471 }
 472
 473 /* *INDENT-OFF* */
 474 VLIB_REGISTER_NODE (esp6_encrypt_node) = {
 475   .name = "esp6-encrypt",
 476   .vector_size = sizeof (u32),
 477   .format_trace = format_esp_encrypt_trace,
 478   .type = VLIB_NODE_TYPE_INTERNAL,
 479
 480   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 481   .error_strings = esp_encrypt_error_strings,
 482
 483   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 484   .next_nodes = {
 485 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 486     foreach_esp_encrypt_next
 487 #undef _
 488   },
 489 };
 490 /* *INDENT-ON* */
 491
 492 /*
 493  * fd.io coding-style-patch-verification: ON
 494  *
 495  * Local Variables:
 496  * eval: (c-set-style "gnu")
 497  * End:
 498  */