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 esp_main_t esp_main;
  26
  27 #define foreach_esp_encrypt_next                   \
  28 _(DROP, "error-drop")                              \
  29 _(IP4_LOOKUP, "ip4-lookup")                        \
  30 _(IP6_LOOKUP, "ip6-lookup")                        \
  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 thread_index = vlib_get_thread_index ();
  93   EVP_CIPHER_CTX *ctx = &(em->per_thread_data[thread_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
 103       (alg != em->per_thread_data[thread_index].last_encrypt_alg))
 104     {
 105       cipher = em->esp_crypto_algs[alg].type;
 106       em->per_thread_data[thread_index].last_encrypt_alg = alg;
 107     }
 108
 109   EVP_EncryptInit_ex (ctx, cipher, NULL, key, iv);
 110
 111   EVP_EncryptUpdate (ctx, out, &out_len, in, in_len);
 112   EVP_EncryptFinal_ex (ctx, out + out_len, &out_len);
 113 }
 114
 115 static uword
 116 esp_encrypt_node_fn (vlib_main_t * vm,
 117                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 118 {
 119   u32 n_left_from, *from, *to_next = 0, next_index;
 120   from = vlib_frame_vector_args (from_frame);
 121   n_left_from = from_frame->n_vectors;
 122   ipsec_main_t *im = &ipsec_main;
 123   u32 *recycle = 0;
 124   u32 thread_index = vlib_get_thread_index ();
 125
 126   ipsec_alloc_empty_buffers (vm, im);
 127
 128   u32 *empty_buffers = im->empty_buffers[thread_index];
 129
 130   if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
 131     {
 132       vlib_node_increment_counter (vm, esp_encrypt_node.index,
 133                                    ESP_ENCRYPT_ERROR_NO_BUFFER, n_left_from);
 134       clib_warning ("no enough empty buffers. discarding frame");
 135       goto free_buffers_and_exit;
 136     }
 137
 138   next_index = node->cached_next_index;
 139
 140   while (n_left_from > 0)
 141     {
 142       u32 n_left_to_next;
 143
 144       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 145
 146       while (n_left_from > 0 && n_left_to_next > 0)
 147         {
 148           u32 i_bi0, o_bi0, next0;
 149           vlib_buffer_t *i_b0, *o_b0 = 0;
 150           u32 sa_index0;
 151           ipsec_sa_t *sa0;
 152           ip4_and_esp_header_t *ih0, *oh0 = 0;
 153           ip6_and_esp_header_t *ih6_0, *oh6_0 = 0;
 154           uword last_empty_buffer;
 155           esp_header_t *o_esp0;
 156           esp_footer_t *f0;
 157           u8 is_ipv6;
 158           u8 ip_hdr_size;
 159           u8 next_hdr_type;
 160           u32 ip_proto = 0;
 161           u8 transport_mode = 0;
 162
 163           i_bi0 = from[0];
 164           from += 1;
 165           n_left_from -= 1;
 166           n_left_to_next -= 1;
 167
 168           next0 = ESP_ENCRYPT_NEXT_DROP;
 169
 170           i_b0 = vlib_get_buffer (vm, i_bi0);
 171           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 172           sa0 = pool_elt_at_index (im->sad, sa_index0);
 173
 174           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 175             {
 176               clib_warning ("sequence number counter has cycled SPI %u",
 177                             sa0->spi);
 178               vlib_node_increment_counter (vm, esp_encrypt_node.index,
 179                                            ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 180               //TODO: rekey SA
 181               o_bi0 = i_bi0;
 182               to_next[0] = o_bi0;
 183               to_next += 1;
 184               goto trace;
 185             }
 186
 187           sa0->total_data_size += i_b0->current_length;
 188
 189           /* grab free buffer */
 190           last_empty_buffer = vec_len (empty_buffers) - 1;
 191           o_bi0 = empty_buffers[last_empty_buffer];
 192           o_b0 = vlib_get_buffer (vm, o_bi0);
 193           o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 194           o_b0->current_data = sizeof (ethernet_header_t);
 195           ih0 = vlib_buffer_get_current (i_b0);
 196           vlib_prefetch_buffer_with_index (vm,
 197                                            empty_buffers[last_empty_buffer -
 198                                                          1], STORE);
 199           _vec_len (empty_buffers) = last_empty_buffer;
 200           to_next[0] = o_bi0;
 201           to_next += 1;
 202
 203           /* add old buffer to the recycle list */
 204           vec_add1 (recycle, i_bi0);
 205
 206           /* is ipv6 */
 207           if (PREDICT_FALSE
 208               ((ih0->ip4.ip_version_and_header_length & 0xF0) == 0x60))
 209             {
 210               is_ipv6 = 1;
 211               ih6_0 = vlib_buffer_get_current (i_b0);
 212               ip_hdr_size = sizeof (ip6_header_t);
 213               next_hdr_type = IP_PROTOCOL_IPV6;
 214               oh6_0 = vlib_buffer_get_current (o_b0);
 215               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof (ip6_header_t);
 216
 217               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 218                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 219               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 220               oh6_0->ip6.hop_limit = 254;
 221               oh6_0->ip6.src_address.as_u64[0] =
 222                 ih6_0->ip6.src_address.as_u64[0];
 223               oh6_0->ip6.src_address.as_u64[1] =
 224                 ih6_0->ip6.src_address.as_u64[1];
 225               oh6_0->ip6.dst_address.as_u64[0] =
 226                 ih6_0->ip6.dst_address.as_u64[0];
 227               oh6_0->ip6.dst_address.as_u64[1] =
 228                 ih6_0->ip6.dst_address.as_u64[1];
 229               oh6_0->esp.spi = clib_net_to_host_u32 (sa0->spi);
 230               oh6_0->esp.seq = clib_net_to_host_u32 (sa0->seq);
 231               ip_proto = ih6_0->ip6.protocol;
 232
 233               next0 = ESP_ENCRYPT_NEXT_IP6_LOOKUP;
 234             }
 235           else
 236             {
 237               is_ipv6 = 0;
 238               ip_hdr_size = sizeof (ip4_header_t);
 239               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 240               oh0 = vlib_buffer_get_current (o_b0);
 241               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof (ip4_header_t);
 242
 243               oh0->ip4.ip_version_and_header_length = 0x45;
 244               oh0->ip4.tos = ih0->ip4.tos;
 245               oh0->ip4.fragment_id = 0;
 246               oh0->ip4.flags_and_fragment_offset = 0;
 247               oh0->ip4.ttl = 254;
 248               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 249               oh0->ip4.src_address.as_u32 = ih0->ip4.src_address.as_u32;
 250               oh0->ip4.dst_address.as_u32 = ih0->ip4.dst_address.as_u32;
 251               oh0->esp.spi = clib_net_to_host_u32 (sa0->spi);
 252               oh0->esp.seq = clib_net_to_host_u32 (sa0->seq);
 253               ip_proto = ih0->ip4.protocol;
 254
 255               next0 = ESP_ENCRYPT_NEXT_IP4_LOOKUP;
 256             }
 257
 258           if (PREDICT_TRUE
 259               (!is_ipv6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 260             {
 261               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 262               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 263
 264               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 265             }
 266           else if (is_ipv6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 267             {
 268               oh6_0->ip6.src_address.as_u64[0] =
 269                 sa0->tunnel_src_addr.ip6.as_u64[0];
 270               oh6_0->ip6.src_address.as_u64[1] =
 271                 sa0->tunnel_src_addr.ip6.as_u64[1];
 272               oh6_0->ip6.dst_address.as_u64[0] =
 273                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 274               oh6_0->ip6.dst_address.as_u64[1] =
 275                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 276
 277               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 278             }
 279           else
 280             {
 281               next_hdr_type = ip_proto;
 282               if (vnet_buffer (i_b0)->sw_if_index[VLIB_TX] != ~0)
 283                 {
 284                   transport_mode = 1;
 285                   ethernet_header_t *ieh0, *oeh0;
 286                   ieh0 =
 287                     (ethernet_header_t *) ((u8 *)
 288                                            vlib_buffer_get_current (i_b0) -
 289                                            sizeof (ethernet_header_t));
 290                   oeh0 = (ethernet_header_t *) o_b0->data;
 291                   clib_memcpy (oeh0, ieh0, sizeof (ethernet_header_t));
 292                   next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 293                   vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 294                     vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 295                 }
 296               vlib_buffer_advance (i_b0, ip_hdr_size);
 297             }
 298
 299           ASSERT (sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 300
 301           if (PREDICT_TRUE (sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE))
 302             {
 303
 304               const int BLOCK_SIZE = 16;
 305               const int IV_SIZE = 16;
 306               int blocks = 1 + (i_b0->current_length + 1) / BLOCK_SIZE;
 307
 308               /* pad packet in input buffer */
 309               u8 pad_bytes = BLOCK_SIZE * blocks - 2 - i_b0->current_length;
 310               u8 i;
 311               u8 *padding =
 312                 vlib_buffer_get_current (i_b0) + i_b0->current_length;
 313               i_b0->current_length = BLOCK_SIZE * blocks;
 314               for (i = 0; i < pad_bytes; ++i)
 315                 {
 316                   padding[i] = i + 1;
 317                 }
 318               f0 = vlib_buffer_get_current (i_b0) + i_b0->current_length - 2;
 319               f0->pad_length = pad_bytes;
 320               f0->next_header = next_hdr_type;
 321
 322               o_b0->current_length = ip_hdr_size + sizeof (esp_header_t) +
 323                 BLOCK_SIZE * blocks + IV_SIZE;
 324
 325               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 326                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 327
 328               u8 iv[16];
 329               RAND_bytes (iv, sizeof (iv));
 330
 331               clib_memcpy ((u8 *) vlib_buffer_get_current (o_b0) +
 332                            ip_hdr_size + sizeof (esp_header_t), iv, 16);
 333
 334               esp_encrypt_aes_cbc (sa0->crypto_alg,
 335                                    (u8 *) vlib_buffer_get_current (i_b0),
 336                                    (u8 *) vlib_buffer_get_current (o_b0) +
 337                                    ip_hdr_size + sizeof (esp_header_t) +
 338                                    IV_SIZE, BLOCK_SIZE * blocks,
 339                                    sa0->crypto_key, iv);
 340             }
 341
 342           o_b0->current_length += hmac_calc (sa0->integ_alg, sa0->integ_key,
 343                                              sa0->integ_key_len,
 344                                              (u8 *) o_esp0,
 345                                              o_b0->current_length -
 346                                              ip_hdr_size,
 347                                              vlib_buffer_get_current (o_b0) +
 348                                              o_b0->current_length,
 349                                              sa0->use_esn, sa0->seq_hi);
 350
 351
 352           if (PREDICT_FALSE (is_ipv6))
 353             {
 354               oh6_0->ip6.payload_length =
 355                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0) -
 356                                       sizeof (ip6_header_t));
 357             }
 358           else
 359             {
 360               oh0->ip4.length =
 361                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0));
 362               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 363             }
 364
 365           if (transport_mode)
 366             vlib_buffer_reset (o_b0);
 367
 368         trace:
 369           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 370             {
 371               if (o_b0)
 372                 {
 373                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 374                   o_b0->trace_index = i_b0->trace_index;
 375                   esp_encrypt_trace_t *tr =
 376                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 377                   tr->spi = sa0->spi;
 378                   tr->seq = sa0->seq - 1;
 379                   tr->crypto_alg = sa0->crypto_alg;
 380                   tr->integ_alg = sa0->integ_alg;
 381                 }
 382             }
 383
 384           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 385                                            to_next, n_left_to_next, o_bi0,
 386                                            next0);
 387         }
 388       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 389     }
 390   vlib_node_increment_counter (vm, esp_encrypt_node.index,
 391                                ESP_ENCRYPT_ERROR_RX_PKTS,
 392                                from_frame->n_vectors);
 393
 394 free_buffers_and_exit:
 395   if (recycle)
 396     vlib_buffer_free (vm, recycle, vec_len (recycle));
 397   vec_free (recycle);
 398   return from_frame->n_vectors;
 399 }
 400
 401
 402 /* *INDENT-OFF* */
 403 VLIB_REGISTER_NODE (esp_encrypt_node) = {
 404   .function = esp_encrypt_node_fn,
 405   .name = "esp-encrypt",
 406   .vector_size = sizeof (u32),
 407   .format_trace = format_esp_encrypt_trace,
 408   .type = VLIB_NODE_TYPE_INTERNAL,
 409
 410   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 411   .error_strings = esp_encrypt_error_strings,
 412
 413   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 414   .next_nodes = {
 415 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 416     foreach_esp_encrypt_next
 417 #undef _
 418   },
 419 };
 420 /* *INDENT-ON* */
 421
 422 VLIB_NODE_FUNCTION_MULTIARCH (esp_encrypt_node, esp_encrypt_node_fn)
 423 /*
 424  * fd.io coding-style-patch-verification: ON
 425  *
 426  * Local Variables:
 427  * eval: (c-set-style "gnu")
 428  * End:
 429  */