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 vlib_node_registration_t esp_encrypt_node;
  64
  65 typedef struct
  66 {
  67   u32 spi;
  68   u32 seq;
  69   u8 udp_encap;
  70   ipsec_crypto_alg_t crypto_alg;
  71   ipsec_integ_alg_t integ_alg;
  72 } esp_encrypt_trace_t;
  73
  74 /* packet trace format function */
  75 static u8 *
  76 format_esp_encrypt_trace (u8 * s, va_list * args)
  77 {
  78   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  79   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  80   esp_encrypt_trace_t *t = va_arg (*args, esp_encrypt_trace_t *);
  81
  82   s = format (s, "esp: spi %u seq %u crypto %U integrity %U%s",
  83               t->spi, t->seq,
  84               format_ipsec_crypto_alg, t->crypto_alg,
  85               format_ipsec_integ_alg, t->integ_alg,
  86               t->udp_encap ? " udp-encap-enabled" : "");
  87   return s;
  88 }
  89
  90 always_inline void
  91 esp_encrypt_cbc (ipsec_crypto_alg_t alg,
  92                  u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
  93 {
  94   ipsec_proto_main_t *em = &ipsec_proto_main;
  95   u32 thread_index = vlib_get_thread_index ();
  96 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
  97   EVP_CIPHER_CTX *ctx = em->per_thread_data[thread_index].encrypt_ctx;
  98 #else
  99   EVP_CIPHER_CTX *ctx = &(em->per_thread_data[thread_index].encrypt_ctx);
 100 #endif
 101   const EVP_CIPHER *cipher = NULL;
 102   int out_len;
 103
 104   ASSERT (alg < IPSEC_CRYPTO_N_ALG);
 105
 106   if (PREDICT_FALSE
 107       (em->ipsec_proto_main_crypto_algs[alg].type == IPSEC_CRYPTO_ALG_NONE))
 108     return;
 109
 110   if (PREDICT_FALSE
 111       (alg != em->per_thread_data[thread_index].last_encrypt_alg))
 112     {
 113       cipher = em->ipsec_proto_main_crypto_algs[alg].type;
 114       em->per_thread_data[thread_index].last_encrypt_alg = alg;
 115     }
 116
 117   EVP_EncryptInit_ex (ctx, cipher, NULL, key, iv);
 118
 119   EVP_EncryptUpdate (ctx, out, &out_len, in, in_len);
 120   EVP_EncryptFinal_ex (ctx, out + out_len, &out_len);
 121 }
 122
 123 static uword
 124 esp_encrypt_node_fn (vlib_main_t * vm,
 125                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 126 {
 127   u32 n_left_from, *from, *to_next = 0, next_index;
 128   from = vlib_frame_vector_args (from_frame);
 129   n_left_from = from_frame->n_vectors;
 130   ipsec_main_t *im = &ipsec_main;
 131   ipsec_proto_main_t *em = &ipsec_proto_main;
 132   u32 *recycle = 0;
 133   u32 thread_index = vlib_get_thread_index ();
 134
 135   ipsec_alloc_empty_buffers (vm, im);
 136
 137   u32 *empty_buffers = im->empty_buffers[thread_index];
 138
 139   if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
 140     {
 141       vlib_node_increment_counter (vm, esp_encrypt_node.index,
 142                                    ESP_ENCRYPT_ERROR_NO_BUFFER, n_left_from);
 143       clib_warning ("no enough empty buffers. discarding frame");
 144       goto free_buffers_and_exit;
 145     }
 146
 147   next_index = node->cached_next_index;
 148
 149   while (n_left_from > 0)
 150     {
 151       u32 n_left_to_next;
 152
 153       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 154
 155       while (n_left_from > 0 && n_left_to_next > 0)
 156         {
 157           u32 i_bi0, o_bi0, next0;
 158           vlib_buffer_t *i_b0, *o_b0 = 0;
 159           u32 sa_index0;
 160           ipsec_sa_t *sa0;
 161           ip4_and_esp_header_t *oh0 = 0;
 162           ip6_and_esp_header_t *ih6_0, *oh6_0 = 0;
 163           ip4_and_udp_and_esp_header_t *iuh0, *ouh0 = 0;
 164           uword last_empty_buffer;
 165           esp_header_t *o_esp0;
 166           esp_footer_t *f0;
 167           u8 is_ipv6;
 168           u8 ip_udp_hdr_size;
 169           u8 next_hdr_type;
 170           u32 ip_proto = 0;
 171           u8 transport_mode = 0;
 172
 173           i_bi0 = from[0];
 174           from += 1;
 175           n_left_from -= 1;
 176           n_left_to_next -= 1;
 177
 178           next0 = ESP_ENCRYPT_NEXT_DROP;
 179
 180           i_b0 = vlib_get_buffer (vm, i_bi0);
 181           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 182           sa0 = pool_elt_at_index (im->sad, sa_index0);
 183
 184           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 185             {
 186               clib_warning ("sequence number counter has cycled SPI %u",
 187                             sa0->spi);
 188               vlib_node_increment_counter (vm, esp_encrypt_node.index,
 189                                            ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 190               //TODO: rekey SA
 191               o_bi0 = i_bi0;
 192               to_next[0] = o_bi0;
 193               to_next += 1;
 194               goto trace;
 195             }
 196
 197           sa0->total_data_size += i_b0->current_length;
 198
 199           /* grab free buffer */
 200           last_empty_buffer = vec_len (empty_buffers) - 1;
 201           o_bi0 = empty_buffers[last_empty_buffer];
 202           o_b0 = vlib_get_buffer (vm, o_bi0);
 203           o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 204           o_b0->current_data = sizeof (ethernet_header_t);
 205           iuh0 = vlib_buffer_get_current (i_b0);
 206           vlib_prefetch_buffer_with_index (vm,
 207                                            empty_buffers[last_empty_buffer -
 208                                                          1], STORE);
 209           _vec_len (empty_buffers) = last_empty_buffer;
 210           to_next[0] = o_bi0;
 211           to_next += 1;
 212
 213           /* add old buffer to the recycle list */
 214           vec_add1 (recycle, i_bi0);
 215
 216           /* is ipv6 */
 217           if (PREDICT_FALSE
 218               ((iuh0->ip4.ip_version_and_header_length & 0xF0) == 0x60))
 219             {
 220               is_ipv6 = 1;
 221               ih6_0 = vlib_buffer_get_current (i_b0);
 222               next_hdr_type = IP_PROTOCOL_IPV6;
 223               oh6_0 = vlib_buffer_get_current (o_b0);
 224
 225               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 226                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 227               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 228               ip_udp_hdr_size = sizeof (ip6_header_t);
 229               o_esp0 = vlib_buffer_get_current (o_b0) + ip_udp_hdr_size;
 230               oh6_0->ip6.hop_limit = 254;
 231               oh6_0->ip6.src_address.as_u64[0] =
 232                 ih6_0->ip6.src_address.as_u64[0];
 233               oh6_0->ip6.src_address.as_u64[1] =
 234                 ih6_0->ip6.src_address.as_u64[1];
 235               oh6_0->ip6.dst_address.as_u64[0] =
 236                 ih6_0->ip6.dst_address.as_u64[0];
 237               oh6_0->ip6.dst_address.as_u64[1] =
 238                 ih6_0->ip6.dst_address.as_u64[1];
 239               o_esp0->spi = clib_net_to_host_u32 (sa0->spi);
 240               o_esp0->seq = clib_net_to_host_u32 (sa0->seq);
 241               ip_proto = ih6_0->ip6.protocol;
 242
 243               next0 = ESP_ENCRYPT_NEXT_IP6_LOOKUP;
 244             }
 245           else
 246             {
 247               is_ipv6 = 0;
 248               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 249               oh0 = vlib_buffer_get_current (o_b0);
 250               ouh0 = vlib_buffer_get_current (o_b0);
 251
 252               oh0->ip4.ip_version_and_header_length = 0x45;
 253               oh0->ip4.tos = iuh0->ip4.tos;
 254               oh0->ip4.fragment_id = 0;
 255               oh0->ip4.flags_and_fragment_offset = 0;
 256               oh0->ip4.ttl = 254;
 257               if (sa0->udp_encap)
 258                 {
 259                   ouh0->udp.src_port =
 260                     clib_host_to_net_u16 (UDP_DST_PORT_ipsec);
 261                   ouh0->udp.dst_port =
 262                     clib_host_to_net_u16 (UDP_DST_PORT_ipsec);
 263                   ouh0->udp.checksum = 0;
 264                   ouh0->ip4.protocol = IP_PROTOCOL_UDP;
 265                   ip_udp_hdr_size =
 266                     sizeof (udp_header_t) + sizeof (ip4_header_t);
 267                 }
 268               else
 269                 {
 270                   oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 271                   ip_udp_hdr_size = sizeof (ip4_header_t);
 272                 }
 273               o_esp0 = vlib_buffer_get_current (o_b0) + ip_udp_hdr_size;
 274               oh0->ip4.src_address.as_u32 = iuh0->ip4.src_address.as_u32;
 275               oh0->ip4.dst_address.as_u32 = iuh0->ip4.dst_address.as_u32;
 276               o_esp0->spi = clib_net_to_host_u32 (sa0->spi);
 277               o_esp0->seq = clib_net_to_host_u32 (sa0->seq);
 278               ip_proto = iuh0->ip4.protocol;
 279
 280               next0 = ESP_ENCRYPT_NEXT_IP4_LOOKUP;
 281             }
 282
 283           if (PREDICT_TRUE
 284               (!is_ipv6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 285             {
 286               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 287               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 288
 289               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 290             }
 291           else if (is_ipv6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 292             {
 293               oh6_0->ip6.src_address.as_u64[0] =
 294                 sa0->tunnel_src_addr.ip6.as_u64[0];
 295               oh6_0->ip6.src_address.as_u64[1] =
 296                 sa0->tunnel_src_addr.ip6.as_u64[1];
 297               oh6_0->ip6.dst_address.as_u64[0] =
 298                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 299               oh6_0->ip6.dst_address.as_u64[1] =
 300                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 301
 302               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 303             }
 304           else
 305             {
 306               next_hdr_type = ip_proto;
 307               if (vnet_buffer (i_b0)->sw_if_index[VLIB_TX] != ~0)
 308                 {
 309                   transport_mode = 1;
 310                   ethernet_header_t *ieh0, *oeh0;
 311                   ieh0 =
 312                     (ethernet_header_t *) ((u8 *)
 313                                            vlib_buffer_get_current (i_b0) -
 314                                            sizeof (ethernet_header_t));
 315                   oeh0 = (ethernet_header_t *) o_b0->data;
 316                   clib_memcpy (oeh0, ieh0, sizeof (ethernet_header_t));
 317                   next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 318                   vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 319                     vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 320                 }
 321               vlib_buffer_advance (i_b0, ip_udp_hdr_size);
 322             }
 323
 324           ASSERT (sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 325
 326           if (PREDICT_TRUE (sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE))
 327             {
 328
 329               const int BLOCK_SIZE =
 330                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;
 331               const int IV_SIZE =
 332                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
 333               int blocks = 1 + (i_b0->current_length + 1) / BLOCK_SIZE;
 334
 335               /* pad packet in input buffer */
 336               u8 pad_bytes = BLOCK_SIZE * blocks - 2 - i_b0->current_length;
 337               u8 i;
 338               u8 *padding =
 339                 vlib_buffer_get_current (i_b0) + i_b0->current_length;
 340               i_b0->current_length = BLOCK_SIZE * blocks;
 341               for (i = 0; i < pad_bytes; ++i)
 342                 {
 343                   padding[i] = i + 1;
 344                 }
 345               f0 = vlib_buffer_get_current (i_b0) + i_b0->current_length - 2;
 346               f0->pad_length = pad_bytes;
 347               f0->next_header = next_hdr_type;
 348
 349               o_b0->current_length = ip_udp_hdr_size + sizeof (esp_header_t) +
 350                 BLOCK_SIZE * blocks + IV_SIZE;
 351
 352               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 353                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 354
 355               u8 iv[em->
 356                     ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size];
 357               RAND_bytes (iv, sizeof (iv));
 358
 359               clib_memcpy ((u8 *) vlib_buffer_get_current (o_b0) +
 360                            ip_udp_hdr_size + sizeof (esp_header_t), iv,
 361                            em->ipsec_proto_main_crypto_algs[sa0->
 362                                                             crypto_alg].iv_size);
 363
 364               esp_encrypt_cbc (sa0->crypto_alg,
 365                                (u8 *) vlib_buffer_get_current (i_b0),
 366                                (u8 *) vlib_buffer_get_current (o_b0) +
 367                                ip_udp_hdr_size + sizeof (esp_header_t) +
 368                                IV_SIZE, BLOCK_SIZE * blocks,
 369                                sa0->crypto_key, iv);
 370             }
 371
 372           o_b0->current_length += hmac_calc (sa0->integ_alg, sa0->integ_key,
 373                                              sa0->integ_key_len,
 374                                              (u8 *) o_esp0,
 375                                              o_b0->current_length -
 376                                              ip_udp_hdr_size,
 377                                              vlib_buffer_get_current (o_b0) +
 378                                              o_b0->current_length,
 379                                              sa0->use_esn, sa0->seq_hi);
 380
 381
 382           if (PREDICT_FALSE (is_ipv6))
 383             {
 384               oh6_0->ip6.payload_length =
 385                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0) -
 386                                       sizeof (ip6_header_t));
 387             }
 388           else
 389             {
 390               oh0->ip4.length =
 391                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0));
 392               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 393               if (sa0->udp_encap)
 394                 {
 395                   ouh0->udp.length =
 396                     clib_host_to_net_u16 (clib_net_to_host_u16
 397                                           (oh0->ip4.length) -
 398                                           ip4_header_bytes (&oh0->ip4));
 399                 }
 400             }
 401
 402           if (transport_mode)
 403             vlib_buffer_reset (o_b0);
 404
 405         trace:
 406           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 407             {
 408               if (o_b0)
 409                 {
 410                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 411                   o_b0->trace_index = i_b0->trace_index;
 412                   esp_encrypt_trace_t *tr =
 413                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 414                   tr->spi = sa0->spi;
 415                   tr->seq = sa0->seq - 1;
 416                   tr->udp_encap = sa0->udp_encap;
 417                   tr->crypto_alg = sa0->crypto_alg;
 418                   tr->integ_alg = sa0->integ_alg;
 419                 }
 420             }
 421
 422           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 423                                            to_next, n_left_to_next, o_bi0,
 424                                            next0);
 425         }
 426       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 427     }
 428   vlib_node_increment_counter (vm, esp_encrypt_node.index,
 429                                ESP_ENCRYPT_ERROR_RX_PKTS,
 430                                from_frame->n_vectors);
 431
 432 free_buffers_and_exit:
 433   if (recycle)
 434     vlib_buffer_free (vm, recycle, vec_len (recycle));
 435   vec_free (recycle);
 436   return from_frame->n_vectors;
 437 }
 438
 439
 440 /* *INDENT-OFF* */
 441 VLIB_REGISTER_NODE (esp_encrypt_node) = {
 442   .function = esp_encrypt_node_fn,
 443   .name = "esp-encrypt",
 444   .vector_size = sizeof (u32),
 445   .format_trace = format_esp_encrypt_trace,
 446   .type = VLIB_NODE_TYPE_INTERNAL,
 447
 448   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 449   .error_strings = esp_encrypt_error_strings,
 450
 451   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 452   .next_nodes = {
 453 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 454     foreach_esp_encrypt_next
 455 #undef _
 456   },
 457 };
 458 /* *INDENT-ON* */
 459
 460 VLIB_NODE_FUNCTION_MULTIARCH (esp_encrypt_node, esp_encrypt_node_fn)
 461 /*
 462  * fd.io coding-style-patch-verification: ON
 463  *
 464  * Local Variables:
 465  * eval: (c-set-style "gnu")
 466  * End:
 467  */