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       if (is_ip6)
 141         vlib_node_increment_counter (vm, esp6_encrypt_node.index,
 142                                      ESP_ENCRYPT_ERROR_NO_BUFFER,
 143                                      n_left_from);
 144       else
 145         vlib_node_increment_counter (vm, esp4_encrypt_node.index,
 146                                      ESP_ENCRYPT_ERROR_NO_BUFFER,
 147                                      n_left_from);
 148       clib_warning ("not enough empty buffers. discarding frame");
 149       goto free_buffers_and_exit;
 150     }
 151
 152   next_index = node->cached_next_index;
 153
 154   while (n_left_from > 0)
 155     {
 156       u32 n_left_to_next;
 157
 158       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 159
 160       while (n_left_from > 0 && n_left_to_next > 0)
 161         {
 162           u32 i_bi0, o_bi0, next0;
 163           vlib_buffer_t *i_b0, *o_b0 = 0;
 164           u32 sa_index0;
 165           ipsec_sa_t *sa0;
 166           ip4_and_esp_header_t *oh0 = 0;
 167           ip6_and_esp_header_t *ih6_0, *oh6_0 = 0;
 168           ip4_and_udp_and_esp_header_t *iuh0, *ouh0 = 0;
 169           uword last_empty_buffer;
 170           esp_header_t *o_esp0;
 171           esp_footer_t *f0;
 172           u8 ip_udp_hdr_size;
 173           u8 next_hdr_type;
 174           u32 ip_proto = 0;
 175           u8 transport_mode = 0;
 176
 177           i_bi0 = from[0];
 178           from += 1;
 179           n_left_from -= 1;
 180           n_left_to_next -= 1;
 181
 182           next0 = ESP_ENCRYPT_NEXT_DROP;
 183
 184           i_b0 = vlib_get_buffer (vm, i_bi0);
 185           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 186           sa0 = pool_elt_at_index (im->sad, sa_index0);
 187
 188           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 189             {
 190               clib_warning ("sequence number counter has cycled SPI %u",
 191                             sa0->spi);
 192               if (is_ip6)
 193                 vlib_node_increment_counter (vm, esp6_encrypt_node.index,
 194                                              ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 195               else
 196                 vlib_node_increment_counter (vm, esp4_encrypt_node.index,
 197                                              ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 198               //TODO: rekey SA
 199               o_bi0 = i_bi0;
 200               to_next[0] = o_bi0;
 201               to_next += 1;
 202               goto trace;
 203             }
 204
 205           sa0->total_data_size += i_b0->current_length;
 206
 207           /* grab free buffer */
 208           last_empty_buffer = vec_len (empty_buffers) - 1;
 209           o_bi0 = empty_buffers[last_empty_buffer];
 210           o_b0 = vlib_get_buffer (vm, o_bi0);
 211           o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 212           o_b0->current_data = sizeof (ethernet_header_t);
 213           iuh0 = vlib_buffer_get_current (i_b0);
 214           vlib_prefetch_buffer_with_index (vm,
 215                                            empty_buffers[last_empty_buffer -
 216                                                          1], STORE);
 217           _vec_len (empty_buffers) = last_empty_buffer;
 218           to_next[0] = o_bi0;
 219           to_next += 1;
 220
 221           /* add old buffer to the recycle list */
 222           vec_add1 (recycle, i_bi0);
 223
 224           if (is_ip6)
 225             {
 226               ih6_0 = vlib_buffer_get_current (i_b0);
 227               next_hdr_type = IP_PROTOCOL_IPV6;
 228               oh6_0 = vlib_buffer_get_current (o_b0);
 229
 230               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 231                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 232               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 233               ip_udp_hdr_size = sizeof (ip6_header_t);
 234               o_esp0 = vlib_buffer_get_current (o_b0) + ip_udp_hdr_size;
 235               oh6_0->ip6.hop_limit = 254;
 236               oh6_0->ip6.src_address.as_u64[0] =
 237                 ih6_0->ip6.src_address.as_u64[0];
 238               oh6_0->ip6.src_address.as_u64[1] =
 239                 ih6_0->ip6.src_address.as_u64[1];
 240               oh6_0->ip6.dst_address.as_u64[0] =
 241                 ih6_0->ip6.dst_address.as_u64[0];
 242               oh6_0->ip6.dst_address.as_u64[1] =
 243                 ih6_0->ip6.dst_address.as_u64[1];
 244               o_esp0->spi = clib_net_to_host_u32 (sa0->spi);
 245               o_esp0->seq = clib_net_to_host_u32 (sa0->seq);
 246               ip_proto = ih6_0->ip6.protocol;
 247
 248               next0 = ESP_ENCRYPT_NEXT_IP6_LOOKUP;
 249             }
 250           else
 251             {
 252               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 253               oh0 = vlib_buffer_get_current (o_b0);
 254               ouh0 = vlib_buffer_get_current (o_b0);
 255
 256               oh0->ip4.ip_version_and_header_length = 0x45;
 257               oh0->ip4.tos = iuh0->ip4.tos;
 258               oh0->ip4.fragment_id = 0;
 259               oh0->ip4.flags_and_fragment_offset = 0;
 260               oh0->ip4.ttl = 254;
 261               if (sa0->udp_encap)
 262                 {
 263                   ouh0->udp.src_port =
 264                     clib_host_to_net_u16 (UDP_DST_PORT_ipsec);
 265                   ouh0->udp.dst_port =
 266                     clib_host_to_net_u16 (UDP_DST_PORT_ipsec);
 267                   ouh0->udp.checksum = 0;
 268                   ouh0->ip4.protocol = IP_PROTOCOL_UDP;
 269                   ip_udp_hdr_size =
 270                     sizeof (udp_header_t) + sizeof (ip4_header_t);
 271                 }
 272               else
 273                 {
 274                   oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 275                   ip_udp_hdr_size = sizeof (ip4_header_t);
 276                 }
 277               o_esp0 = vlib_buffer_get_current (o_b0) + ip_udp_hdr_size;
 278               oh0->ip4.src_address.as_u32 = iuh0->ip4.src_address.as_u32;
 279               oh0->ip4.dst_address.as_u32 = iuh0->ip4.dst_address.as_u32;
 280               o_esp0->spi = clib_net_to_host_u32 (sa0->spi);
 281               o_esp0->seq = clib_net_to_host_u32 (sa0->seq);
 282               ip_proto = iuh0->ip4.protocol;
 283
 284               next0 = ESP_ENCRYPT_NEXT_IP4_LOOKUP;
 285             }
 286
 287           if (PREDICT_TRUE (!is_ip6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 288             {
 289               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 290               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 291
 292               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 293             }
 294           else if (is_ip6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 295             {
 296               oh6_0->ip6.src_address.as_u64[0] =
 297                 sa0->tunnel_src_addr.ip6.as_u64[0];
 298               oh6_0->ip6.src_address.as_u64[1] =
 299                 sa0->tunnel_src_addr.ip6.as_u64[1];
 300               oh6_0->ip6.dst_address.as_u64[0] =
 301                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 302               oh6_0->ip6.dst_address.as_u64[1] =
 303                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 304
 305               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 306             }
 307           else
 308             {
 309               next_hdr_type = ip_proto;
 310               if (vnet_buffer (i_b0)->sw_if_index[VLIB_TX] != ~0)
 311                 {
 312                   transport_mode = 1;
 313                   ethernet_header_t *ieh0, *oeh0;
 314                   ieh0 =
 315                     (ethernet_header_t *) ((u8 *)
 316                                            vlib_buffer_get_current (i_b0) -
 317                                            sizeof (ethernet_header_t));
 318                   oeh0 = (ethernet_header_t *) o_b0->data;
 319                   clib_memcpy (oeh0, ieh0, sizeof (ethernet_header_t));
 320                   next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 321                   vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 322                     vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 323                 }
 324               vlib_buffer_advance (i_b0, ip_udp_hdr_size);
 325             }
 326
 327           ASSERT (sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 328
 329           if (PREDICT_TRUE (sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE))
 330             {
 331
 332               const int BLOCK_SIZE =
 333                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;
 334               const int IV_SIZE =
 335                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
 336               int blocks = 1 + (i_b0->current_length + 1) / BLOCK_SIZE;
 337
 338               /* pad packet in input buffer */
 339               u8 pad_bytes = BLOCK_SIZE * blocks - 2 - i_b0->current_length;
 340               u8 i;
 341               u8 *padding =
 342                 vlib_buffer_get_current (i_b0) + i_b0->current_length;
 343               i_b0->current_length = BLOCK_SIZE * blocks;
 344               for (i = 0; i < pad_bytes; ++i)
 345                 {
 346                   padding[i] = i + 1;
 347                 }
 348               f0 = vlib_buffer_get_current (i_b0) + i_b0->current_length - 2;
 349               f0->pad_length = pad_bytes;
 350               f0->next_header = next_hdr_type;
 351
 352               o_b0->current_length = ip_udp_hdr_size + sizeof (esp_header_t) +
 353                 BLOCK_SIZE * blocks + IV_SIZE;
 354
 355               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 356                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 357
 358               u8 iv[em->
 359                     ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size];
 360               RAND_bytes (iv, sizeof (iv));
 361
 362               clib_memcpy ((u8 *) vlib_buffer_get_current (o_b0) +
 363                            ip_udp_hdr_size + sizeof (esp_header_t), iv,
 364                            em->ipsec_proto_main_crypto_algs[sa0->
 365                                                             crypto_alg].iv_size);
 366
 367               esp_encrypt_cbc (vm, sa0->crypto_alg,
 368                                (u8 *) vlib_buffer_get_current (i_b0),
 369                                (u8 *) vlib_buffer_get_current (o_b0) +
 370                                ip_udp_hdr_size + sizeof (esp_header_t) +
 371                                IV_SIZE, BLOCK_SIZE * blocks,
 372                                sa0->crypto_key, iv);
 373             }
 374
 375           o_b0->current_length += hmac_calc (sa0->integ_alg, sa0->integ_key,
 376                                              sa0->integ_key_len,
 377                                              (u8 *) o_esp0,
 378                                              o_b0->current_length -
 379                                              ip_udp_hdr_size,
 380                                              vlib_buffer_get_current (o_b0) +
 381                                              o_b0->current_length,
 382                                              sa0->use_esn, sa0->seq_hi);
 383
 384
 385           if (is_ip6)
 386             {
 387               oh6_0->ip6.payload_length =
 388                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0) -
 389                                       sizeof (ip6_header_t));
 390             }
 391           else
 392             {
 393               oh0->ip4.length =
 394                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0));
 395               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 396               if (sa0->udp_encap)
 397                 {
 398                   ouh0->udp.length =
 399                     clib_host_to_net_u16 (clib_net_to_host_u16
 400                                           (oh0->ip4.length) -
 401                                           ip4_header_bytes (&oh0->ip4));
 402                 }
 403             }
 404
 405           if (transport_mode)
 406             vlib_buffer_reset (o_b0);
 407
 408         trace:
 409           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 410             {
 411               if (o_b0)
 412                 {
 413                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 414                   o_b0->trace_index = i_b0->trace_index;
 415                   esp_encrypt_trace_t *tr =
 416                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 417                   tr->spi = sa0->spi;
 418                   tr->seq = sa0->seq - 1;
 419                   tr->udp_encap = sa0->udp_encap;
 420                   tr->crypto_alg = sa0->crypto_alg;
 421                   tr->integ_alg = sa0->integ_alg;
 422                 }
 423             }
 424
 425           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 426                                            to_next, n_left_to_next, o_bi0,
 427                                            next0);
 428         }
 429       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 430     }
 431   if (is_ip6)
 432     vlib_node_increment_counter (vm, esp6_encrypt_node.index,
 433                                  ESP_ENCRYPT_ERROR_RX_PKTS,
 434                                  from_frame->n_vectors);
 435   else
 436     vlib_node_increment_counter (vm, esp4_encrypt_node.index,
 437                                  ESP_ENCRYPT_ERROR_RX_PKTS,
 438                                  from_frame->n_vectors);
 439
 440 free_buffers_and_exit:
 441   if (recycle)
 442     vlib_buffer_free (vm, recycle, vec_len (recycle));
 443   vec_free (recycle);
 444   return from_frame->n_vectors;
 445 }
 446
 447 VLIB_NODE_FN (esp4_encrypt_node) (vlib_main_t * vm,
 448                                   vlib_node_runtime_t * node,
 449                                   vlib_frame_t * from_frame)
 450 {
 451   return esp_encrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 452 }
 453
 454 /* *INDENT-OFF* */
 455 VLIB_REGISTER_NODE (esp4_encrypt_node) = {
 456   .name = "esp4-encrypt",
 457   .vector_size = sizeof (u32),
 458   .format_trace = format_esp_encrypt_trace,
 459   .type = VLIB_NODE_TYPE_INTERNAL,
 460
 461   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 462   .error_strings = esp_encrypt_error_strings,
 463
 464   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 465   .next_nodes = {
 466 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 467     foreach_esp_encrypt_next
 468 #undef _
 469   },
 470 };
 471 /* *INDENT-ON* */
 472
 473 VLIB_NODE_FN (esp6_encrypt_node) (vlib_main_t * vm,
 474                                   vlib_node_runtime_t * node,
 475                                   vlib_frame_t * from_frame)
 476 {
 477   return esp_encrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 478 }
 479
 480 /* *INDENT-OFF* */
 481 VLIB_REGISTER_NODE (esp6_encrypt_node) = {
 482   .name = "esp6-encrypt",
 483   .vector_size = sizeof (u32),
 484   .format_trace = format_esp_encrypt_trace,
 485   .type = VLIB_NODE_TYPE_INTERNAL,
 486
 487   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 488   .error_strings = esp_encrypt_error_strings,
 489
 490   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 491   .next_nodes = {
 492 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 493     foreach_esp_encrypt_next
 494 #undef _
 495   },
 496 };
 497 /* *INDENT-ON* */
 498
 499 /*
 500  * fd.io coding-style-patch-verification: ON
 501  *
 502  * Local Variables:
 503  * eval: (c-set-style "gnu")
 504  * End:
 505  */