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
  22 #include <vnet/ipsec/ipsec.h>
  23 #include <vnet/ipsec/esp.h>
  24
  25
  26 #define foreach_esp_encrypt_next                   \
  27 _(DROP, "error-drop")                              \
  28 _(IP4_LOOKUP, "ip4-lookup")                        \
  29 _(IP6_LOOKUP, "ip6-lookup")                        \
  30 _(INTERFACE_OUTPUT, "interface-output")
  31
  32 #define _(v, s) ESP_ENCRYPT_NEXT_##v,
  33 typedef enum
  34 {
  35   foreach_esp_encrypt_next
  36 #undef _
  37     ESP_ENCRYPT_N_NEXT,
  38 } esp_encrypt_next_t;
  39
  40 #define foreach_esp_encrypt_error                   \
  41  _(RX_PKTS, "ESP pkts received")                    \
  42  _(NO_BUFFER, "No buffer (packet dropped)")         \
  43  _(DECRYPTION_FAILED, "ESP encryption failed")      \
  44  _(SEQ_CYCLED, "sequence number cycled")
  45
  46
  47 typedef enum
  48 {
  49 #define _(sym,str) ESP_ENCRYPT_ERROR_##sym,
  50   foreach_esp_encrypt_error
  51 #undef _
  52     ESP_ENCRYPT_N_ERROR,
  53 } esp_encrypt_error_t;
  54
  55 static char *esp_encrypt_error_strings[] = {
  56 #define _(sym,string) string,
  57   foreach_esp_encrypt_error
  58 #undef _
  59 };
  60
  61 vlib_node_registration_t esp_encrypt_node;
  62
  63 typedef struct
  64 {
  65   u32 spi;
  66   u32 seq;
  67   ipsec_crypto_alg_t crypto_alg;
  68   ipsec_integ_alg_t integ_alg;
  69 } esp_encrypt_trace_t;
  70
  71 /* packet trace format function */
  72 static u8 *
  73 format_esp_encrypt_trace (u8 * s, va_list * args)
  74 {
  75   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  76   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  77   esp_encrypt_trace_t *t = va_arg (*args, esp_encrypt_trace_t *);
  78
  79   s = format (s, "esp: spi %u seq %u crypto %U integrity %U",
  80               t->spi, t->seq,
  81               format_ipsec_crypto_alg, t->crypto_alg,
  82               format_ipsec_integ_alg, t->integ_alg);
  83   return s;
  84 }
  85
  86 always_inline void
  87 esp_encrypt_aes_cbc (ipsec_crypto_alg_t alg,
  88                      u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
  89 {
  90   esp_main_t *em = &esp_main;
  91   u32 cpu_index = os_get_cpu_number ();
  92   EVP_CIPHER_CTX *ctx = &(em->per_thread_data[cpu_index].encrypt_ctx);
  93   const EVP_CIPHER *cipher = NULL;
  94   int out_len;
  95
  96   ASSERT (alg < IPSEC_CRYPTO_N_ALG);
  97
  98   if (PREDICT_FALSE (em->esp_crypto_algs[alg].type == IPSEC_CRYPTO_ALG_NONE))
  99     return;
 100
 101   if (PREDICT_FALSE (alg != em->per_thread_data[cpu_index].last_encrypt_alg))
 102     {
 103       cipher = em->esp_crypto_algs[alg].type;
 104       em->per_thread_data[cpu_index].last_encrypt_alg = alg;
 105     }
 106
 107   EVP_EncryptInit_ex (ctx, cipher, NULL, key, iv);
 108
 109   EVP_EncryptUpdate (ctx, out, &out_len, in, in_len);
 110   EVP_EncryptFinal_ex (ctx, out + out_len, &out_len);
 111 }
 112
 113 static uword
 114 esp_encrypt_node_fn (vlib_main_t * vm,
 115                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 116 {
 117   u32 n_left_from, *from, *to_next = 0, next_index;
 118   from = vlib_frame_vector_args (from_frame);
 119   n_left_from = from_frame->n_vectors;
 120   ipsec_main_t *im = &ipsec_main;
 121   u32 *recycle = 0;
 122   u32 cpu_index = os_get_cpu_number ();
 123
 124   ipsec_alloc_empty_buffers (vm, im);
 125
 126   u32 *empty_buffers = im->empty_buffers[cpu_index];
 127
 128   if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
 129     {
 130       vlib_node_increment_counter (vm, esp_encrypt_node.index,
 131                                    ESP_ENCRYPT_ERROR_NO_BUFFER, n_left_from);
 132       clib_warning ("no enough empty buffers. discarding frame");
 133       goto free_buffers_and_exit;
 134     }
 135
 136   next_index = node->cached_next_index;
 137
 138   while (n_left_from > 0)
 139     {
 140       u32 n_left_to_next;
 141
 142       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 143
 144       while (n_left_from > 0 && n_left_to_next > 0)
 145         {
 146           u32 i_bi0, o_bi0, next0;
 147           vlib_buffer_t *i_b0, *o_b0 = 0;
 148           u32 sa_index0;
 149           ipsec_sa_t *sa0;
 150           ip4_and_esp_header_t *ih0, *oh0 = 0;
 151           ip6_and_esp_header_t *ih6_0, *oh6_0 = 0;
 152           uword last_empty_buffer;
 153           esp_header_t *o_esp0;
 154           esp_footer_t *f0;
 155           u8 is_ipv6;
 156           u8 ip_hdr_size;
 157           u8 next_hdr_type;
 158           u32 ip_proto = 0;
 159           u8 transport_mode = 0;
 160
 161           i_bi0 = from[0];
 162           from += 1;
 163           n_left_from -= 1;
 164           n_left_to_next -= 1;
 165
 166           next0 = ESP_ENCRYPT_NEXT_DROP;
 167
 168           i_b0 = vlib_get_buffer (vm, i_bi0);
 169           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 170           sa0 = pool_elt_at_index (im->sad, sa_index0);
 171
 172           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 173             {
 174               clib_warning ("sequence number counter has cycled SPI %u",
 175                             sa0->spi);
 176               vlib_node_increment_counter (vm, esp_encrypt_node.index,
 177                                            ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 178               //TODO: rekey SA
 179               o_bi0 = i_bi0;
 180               to_next[0] = o_bi0;
 181               to_next += 1;
 182               goto trace;
 183             }
 184
 185           /* grab free buffer */
 186           last_empty_buffer = vec_len (empty_buffers) - 1;
 187           o_bi0 = empty_buffers[last_empty_buffer];
 188           o_b0 = vlib_get_buffer (vm, o_bi0);
 189           o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 190           o_b0->current_data = sizeof (ethernet_header_t);
 191           ih0 = vlib_buffer_get_current (i_b0);
 192           vlib_prefetch_buffer_with_index (vm,
 193                                            empty_buffers[last_empty_buffer -
 194                                                          1], STORE);
 195           _vec_len (empty_buffers) = last_empty_buffer;
 196           to_next[0] = o_bi0;
 197           to_next += 1;
 198
 199           /* add old buffer to the recycle list */
 200           vec_add1 (recycle, i_bi0);
 201
 202           /* is ipv6 */
 203           if (PREDICT_FALSE
 204               ((ih0->ip4.ip_version_and_header_length & 0xF0) == 0x60))
 205             {
 206               is_ipv6 = 1;
 207               ih6_0 = vlib_buffer_get_current (i_b0);
 208               ip_hdr_size = sizeof (ip6_header_t);
 209               next_hdr_type = IP_PROTOCOL_IPV6;
 210               oh6_0 = vlib_buffer_get_current (o_b0);
 211               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof (ip6_header_t);
 212
 213               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 214                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 215               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 216               oh6_0->ip6.hop_limit = 254;
 217               oh6_0->ip6.src_address.as_u64[0] =
 218                 ih6_0->ip6.src_address.as_u64[0];
 219               oh6_0->ip6.src_address.as_u64[1] =
 220                 ih6_0->ip6.src_address.as_u64[1];
 221               oh6_0->ip6.dst_address.as_u64[0] =
 222                 ih6_0->ip6.dst_address.as_u64[0];
 223               oh6_0->ip6.dst_address.as_u64[1] =
 224                 ih6_0->ip6.dst_address.as_u64[1];
 225               oh6_0->esp.spi = clib_net_to_host_u32 (sa0->spi);
 226               oh6_0->esp.seq = clib_net_to_host_u32 (sa0->seq);
 227               ip_proto = ih6_0->ip6.protocol;
 228
 229               next0 = ESP_ENCRYPT_NEXT_IP6_LOOKUP;
 230             }
 231           else
 232             {
 233               is_ipv6 = 0;
 234               ip_hdr_size = sizeof (ip4_header_t);
 235               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 236               oh0 = vlib_buffer_get_current (o_b0);
 237               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof (ip4_header_t);
 238
 239               oh0->ip4.ip_version_and_header_length = 0x45;
 240               oh0->ip4.tos = ih0->ip4.tos;
 241               oh0->ip4.fragment_id = 0;
 242               oh0->ip4.flags_and_fragment_offset = 0;
 243               oh0->ip4.ttl = 254;
 244               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 245               oh0->ip4.src_address.as_u32 = ih0->ip4.src_address.as_u32;
 246               oh0->ip4.dst_address.as_u32 = ih0->ip4.dst_address.as_u32;
 247               oh0->esp.spi = clib_net_to_host_u32 (sa0->spi);
 248               oh0->esp.seq = clib_net_to_host_u32 (sa0->seq);
 249               ip_proto = ih0->ip4.protocol;
 250
 251               next0 = ESP_ENCRYPT_NEXT_IP4_LOOKUP;
 252             }
 253
 254           if (PREDICT_TRUE
 255               (!is_ipv6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 256             {
 257               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 258               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 259
 260               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 261             }
 262           else if (is_ipv6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 263             {
 264               oh6_0->ip6.src_address.as_u64[0] =
 265                 sa0->tunnel_src_addr.ip6.as_u64[0];
 266               oh6_0->ip6.src_address.as_u64[1] =
 267                 sa0->tunnel_src_addr.ip6.as_u64[1];
 268               oh6_0->ip6.dst_address.as_u64[0] =
 269                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 270               oh6_0->ip6.dst_address.as_u64[1] =
 271                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 272
 273               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 274             }
 275           else
 276             {
 277               next_hdr_type = ip_proto;
 278               if (vnet_buffer (i_b0)->sw_if_index[VLIB_TX] != ~0)
 279                 {
 280                   transport_mode = 1;
 281                   ethernet_header_t *ieh0, *oeh0;
 282                   ieh0 =
 283                     (ethernet_header_t *) ((u8 *)
 284                                            vlib_buffer_get_current (i_b0) -
 285                                            sizeof (ethernet_header_t));
 286                   oeh0 = (ethernet_header_t *) o_b0->data;
 287                   clib_memcpy (oeh0, ieh0, sizeof (ethernet_header_t));
 288                   next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 289                   vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 290                     vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 291                 }
 292               vlib_buffer_advance (i_b0, ip_hdr_size);
 293             }
 294
 295           ASSERT (sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 296
 297           if (PREDICT_TRUE (sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE))
 298             {
 299
 300               const int BLOCK_SIZE = 16;
 301               const int IV_SIZE = 16;
 302               int blocks = 1 + (i_b0->current_length + 1) / BLOCK_SIZE;
 303
 304               /* pad packet in input buffer */
 305               u8 pad_bytes = BLOCK_SIZE * blocks - 2 - i_b0->current_length;
 306               u8 i;
 307               u8 *padding =
 308                 vlib_buffer_get_current (i_b0) + i_b0->current_length;
 309               i_b0->current_length = BLOCK_SIZE * blocks;
 310               for (i = 0; i < pad_bytes; ++i)
 311                 {
 312                   padding[i] = i + 1;
 313                 }
 314               f0 = vlib_buffer_get_current (i_b0) + i_b0->current_length - 2;
 315               f0->pad_length = pad_bytes;
 316               f0->next_header = next_hdr_type;
 317
 318               o_b0->current_length = ip_hdr_size + sizeof (esp_header_t) +
 319                 BLOCK_SIZE * blocks + IV_SIZE;
 320
 321               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 322                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 323
 324               u8 iv[16];
 325               RAND_bytes (iv, sizeof (iv));
 326
 327               clib_memcpy ((u8 *) vlib_buffer_get_current (o_b0) +
 328                            ip_hdr_size + sizeof (esp_header_t), iv, 16);
 329
 330               esp_encrypt_aes_cbc (sa0->crypto_alg,
 331                                    (u8 *) vlib_buffer_get_current (i_b0),
 332                                    (u8 *) vlib_buffer_get_current (o_b0) +
 333                                    ip_hdr_size + sizeof (esp_header_t) +
 334                                    IV_SIZE, BLOCK_SIZE * blocks,
 335                                    sa0->crypto_key, iv);
 336             }
 337
 338           o_b0->current_length += hmac_calc (sa0->integ_alg, sa0->integ_key,
 339                                              sa0->integ_key_len,
 340                                              (u8 *) o_esp0,
 341                                              o_b0->current_length -
 342                                              ip_hdr_size,
 343                                              vlib_buffer_get_current (o_b0) +
 344                                              o_b0->current_length,
 345                                              sa0->use_esn, sa0->seq_hi);
 346
 347
 348           if (PREDICT_FALSE (is_ipv6))
 349             {
 350               oh6_0->ip6.payload_length =
 351                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0) -
 352                                       sizeof (ip6_header_t));
 353             }
 354           else
 355             {
 356               oh0->ip4.length =
 357                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0));
 358               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 359             }
 360
 361           if (transport_mode)
 362             vlib_buffer_reset (o_b0);
 363
 364         trace:
 365           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 366             {
 367               if (o_b0)
 368                 {
 369                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 370                   o_b0->trace_index = i_b0->trace_index;
 371                   esp_encrypt_trace_t *tr =
 372                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 373                   tr->spi = sa0->spi;
 374                   tr->seq = sa0->seq - 1;
 375                   tr->crypto_alg = sa0->crypto_alg;
 376                   tr->integ_alg = sa0->integ_alg;
 377                 }
 378             }
 379
 380           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 381                                            to_next, n_left_to_next, o_bi0,
 382                                            next0);
 383         }
 384       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 385     }
 386   vlib_node_increment_counter (vm, esp_encrypt_node.index,
 387                                ESP_ENCRYPT_ERROR_RX_PKTS,
 388                                from_frame->n_vectors);
 389
 390 free_buffers_and_exit:
 391   if (recycle)
 392     vlib_buffer_free (vm, recycle, vec_len (recycle));
 393   vec_free (recycle);
 394   return from_frame->n_vectors;
 395 }
 396
 397
 398 /* *INDENT-OFF* */
 399 VLIB_REGISTER_NODE (esp_encrypt_node) = {
 400   .function = esp_encrypt_node_fn,
 401   .name = "esp-encrypt",
 402   .vector_size = sizeof (u32),
 403   .format_trace = format_esp_encrypt_trace,
 404   .type = VLIB_NODE_TYPE_INTERNAL,
 405
 406   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 407   .error_strings = esp_encrypt_error_strings,
 408
 409   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 410   .next_nodes = {
 411 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 412     foreach_esp_encrypt_next
 413 #undef _
 414   },
 415 };
 416 /* *INDENT-ON* */
 417
 418 VLIB_NODE_FUNCTION_MULTIARCH (esp_encrypt_node, esp_encrypt_node_fn)
 419 /*
 420  * fd.io coding-style-patch-verification: ON
 421  *
 422  * Local Variables:
 423  * eval: (c-set-style "gnu")
 424  * End:
 425  */