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 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
  94   EVP_CIPHER_CTX *ctx = em->per_thread_data[thread_index].encrypt_ctx;
  95 #else
  96   EVP_CIPHER_CTX *ctx = &(em->per_thread_data[thread_index].encrypt_ctx);
  97 #endif
  98   const EVP_CIPHER *cipher = NULL;
  99   int out_len;
 100
 101   ASSERT (alg < IPSEC_CRYPTO_N_ALG);
 102
 103   if (PREDICT_FALSE (em->esp_crypto_algs[alg].type == IPSEC_CRYPTO_ALG_NONE))
 104     return;
 105
 106   if (PREDICT_FALSE
 107       (alg != em->per_thread_data[thread_index].last_encrypt_alg))
 108     {
 109       cipher = em->esp_crypto_algs[alg].type;
 110       em->per_thread_data[thread_index].last_encrypt_alg = alg;
 111     }
 112
 113   EVP_EncryptInit_ex (ctx, cipher, NULL, key, iv);
 114
 115   EVP_EncryptUpdate (ctx, out, &out_len, in, in_len);
 116   EVP_EncryptFinal_ex (ctx, out + out_len, &out_len);
 117 }
 118
 119 static uword
 120 esp_encrypt_node_fn (vlib_main_t * vm,
 121                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 122 {
 123   u32 n_left_from, *from, *to_next = 0, next_index;
 124   from = vlib_frame_vector_args (from_frame);
 125   n_left_from = from_frame->n_vectors;
 126   ipsec_main_t *im = &ipsec_main;
 127   u32 *recycle = 0;
 128   u32 thread_index = vlib_get_thread_index ();
 129
 130   ipsec_alloc_empty_buffers (vm, im);
 131
 132   u32 *empty_buffers = im->empty_buffers[thread_index];
 133
 134   if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
 135     {
 136       vlib_node_increment_counter (vm, esp_encrypt_node.index,
 137                                    ESP_ENCRYPT_ERROR_NO_BUFFER, n_left_from);
 138       clib_warning ("no enough empty buffers. discarding frame");
 139       goto free_buffers_and_exit;
 140     }
 141
 142   next_index = node->cached_next_index;
 143
 144   while (n_left_from > 0)
 145     {
 146       u32 n_left_to_next;
 147
 148       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 149
 150       while (n_left_from > 0 && n_left_to_next > 0)
 151         {
 152           u32 i_bi0, o_bi0, next0;
 153           vlib_buffer_t *i_b0, *o_b0 = 0;
 154           u32 sa_index0;
 155           ipsec_sa_t *sa0;
 156           ip4_and_esp_header_t *ih0, *oh0 = 0;
 157           ip6_and_esp_header_t *ih6_0, *oh6_0 = 0;
 158           uword last_empty_buffer;
 159           esp_header_t *o_esp0;
 160           esp_footer_t *f0;
 161           u8 is_ipv6;
 162           u8 ip_hdr_size;
 163           u8 next_hdr_type;
 164           u32 ip_proto = 0;
 165           u8 transport_mode = 0;
 166
 167           i_bi0 = from[0];
 168           from += 1;
 169           n_left_from -= 1;
 170           n_left_to_next -= 1;
 171
 172           next0 = ESP_ENCRYPT_NEXT_DROP;
 173
 174           i_b0 = vlib_get_buffer (vm, i_bi0);
 175           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 176           sa0 = pool_elt_at_index (im->sad, sa_index0);
 177
 178           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 179             {
 180               clib_warning ("sequence number counter has cycled SPI %u",
 181                             sa0->spi);
 182               vlib_node_increment_counter (vm, esp_encrypt_node.index,
 183                                            ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 184               //TODO: rekey SA
 185               o_bi0 = i_bi0;
 186               to_next[0] = o_bi0;
 187               to_next += 1;
 188               goto trace;
 189             }
 190
 191           sa0->total_data_size += i_b0->current_length;
 192
 193           /* grab free buffer */
 194           last_empty_buffer = vec_len (empty_buffers) - 1;
 195           o_bi0 = empty_buffers[last_empty_buffer];
 196           o_b0 = vlib_get_buffer (vm, o_bi0);
 197           o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 198           o_b0->current_data = sizeof (ethernet_header_t);
 199           ih0 = vlib_buffer_get_current (i_b0);
 200           vlib_prefetch_buffer_with_index (vm,
 201                                            empty_buffers[last_empty_buffer -
 202                                                          1], STORE);
 203           _vec_len (empty_buffers) = last_empty_buffer;
 204           to_next[0] = o_bi0;
 205           to_next += 1;
 206
 207           /* add old buffer to the recycle list */
 208           vec_add1 (recycle, i_bi0);
 209
 210           /* is ipv6 */
 211           if (PREDICT_FALSE
 212               ((ih0->ip4.ip_version_and_header_length & 0xF0) == 0x60))
 213             {
 214               is_ipv6 = 1;
 215               ih6_0 = vlib_buffer_get_current (i_b0);
 216               ip_hdr_size = sizeof (ip6_header_t);
 217               next_hdr_type = IP_PROTOCOL_IPV6;
 218               oh6_0 = vlib_buffer_get_current (o_b0);
 219               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof (ip6_header_t);
 220
 221               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 222                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 223               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 224               oh6_0->ip6.hop_limit = 254;
 225               oh6_0->ip6.src_address.as_u64[0] =
 226                 ih6_0->ip6.src_address.as_u64[0];
 227               oh6_0->ip6.src_address.as_u64[1] =
 228                 ih6_0->ip6.src_address.as_u64[1];
 229               oh6_0->ip6.dst_address.as_u64[0] =
 230                 ih6_0->ip6.dst_address.as_u64[0];
 231               oh6_0->ip6.dst_address.as_u64[1] =
 232                 ih6_0->ip6.dst_address.as_u64[1];
 233               oh6_0->esp.spi = clib_net_to_host_u32 (sa0->spi);
 234               oh6_0->esp.seq = clib_net_to_host_u32 (sa0->seq);
 235               ip_proto = ih6_0->ip6.protocol;
 236
 237               next0 = ESP_ENCRYPT_NEXT_IP6_LOOKUP;
 238             }
 239           else
 240             {
 241               is_ipv6 = 0;
 242               ip_hdr_size = sizeof (ip4_header_t);
 243               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 244               oh0 = vlib_buffer_get_current (o_b0);
 245               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof (ip4_header_t);
 246
 247               oh0->ip4.ip_version_and_header_length = 0x45;
 248               oh0->ip4.tos = ih0->ip4.tos;
 249               oh0->ip4.fragment_id = 0;
 250               oh0->ip4.flags_and_fragment_offset = 0;
 251               oh0->ip4.ttl = 254;
 252               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 253               oh0->ip4.src_address.as_u32 = ih0->ip4.src_address.as_u32;
 254               oh0->ip4.dst_address.as_u32 = ih0->ip4.dst_address.as_u32;
 255               oh0->esp.spi = clib_net_to_host_u32 (sa0->spi);
 256               oh0->esp.seq = clib_net_to_host_u32 (sa0->seq);
 257               ip_proto = ih0->ip4.protocol;
 258
 259               next0 = ESP_ENCRYPT_NEXT_IP4_LOOKUP;
 260             }
 261
 262           if (PREDICT_TRUE
 263               (!is_ipv6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 264             {
 265               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 266               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 267
 268               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 269             }
 270           else if (is_ipv6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 271             {
 272               oh6_0->ip6.src_address.as_u64[0] =
 273                 sa0->tunnel_src_addr.ip6.as_u64[0];
 274               oh6_0->ip6.src_address.as_u64[1] =
 275                 sa0->tunnel_src_addr.ip6.as_u64[1];
 276               oh6_0->ip6.dst_address.as_u64[0] =
 277                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 278               oh6_0->ip6.dst_address.as_u64[1] =
 279                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 280
 281               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 282             }
 283           else
 284             {
 285               next_hdr_type = ip_proto;
 286               if (vnet_buffer (i_b0)->sw_if_index[VLIB_TX] != ~0)
 287                 {
 288                   transport_mode = 1;
 289                   ethernet_header_t *ieh0, *oeh0;
 290                   ieh0 =
 291                     (ethernet_header_t *) ((u8 *)
 292                                            vlib_buffer_get_current (i_b0) -
 293                                            sizeof (ethernet_header_t));
 294                   oeh0 = (ethernet_header_t *) o_b0->data;
 295                   clib_memcpy (oeh0, ieh0, sizeof (ethernet_header_t));
 296                   next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 297                   vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 298                     vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 299                 }
 300               vlib_buffer_advance (i_b0, ip_hdr_size);
 301             }
 302
 303           ASSERT (sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 304
 305           if (PREDICT_TRUE (sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE))
 306             {
 307
 308               const int BLOCK_SIZE = 16;
 309               const int IV_SIZE = 16;
 310               int blocks = 1 + (i_b0->current_length + 1) / BLOCK_SIZE;
 311
 312               /* pad packet in input buffer */
 313               u8 pad_bytes = BLOCK_SIZE * blocks - 2 - i_b0->current_length;
 314               u8 i;
 315               u8 *padding =
 316                 vlib_buffer_get_current (i_b0) + i_b0->current_length;
 317               i_b0->current_length = BLOCK_SIZE * blocks;
 318               for (i = 0; i < pad_bytes; ++i)
 319                 {
 320                   padding[i] = i + 1;
 321                 }
 322               f0 = vlib_buffer_get_current (i_b0) + i_b0->current_length - 2;
 323               f0->pad_length = pad_bytes;
 324               f0->next_header = next_hdr_type;
 325
 326               o_b0->current_length = ip_hdr_size + sizeof (esp_header_t) +
 327                 BLOCK_SIZE * blocks + IV_SIZE;
 328
 329               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 330                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 331
 332               u8 iv[16];
 333               RAND_bytes (iv, sizeof (iv));
 334
 335               clib_memcpy ((u8 *) vlib_buffer_get_current (o_b0) +
 336                            ip_hdr_size + sizeof (esp_header_t), iv, 16);
 337
 338               esp_encrypt_aes_cbc (sa0->crypto_alg,
 339                                    (u8 *) vlib_buffer_get_current (i_b0),
 340                                    (u8 *) vlib_buffer_get_current (o_b0) +
 341                                    ip_hdr_size + sizeof (esp_header_t) +
 342                                    IV_SIZE, BLOCK_SIZE * blocks,
 343                                    sa0->crypto_key, iv);
 344             }
 345
 346           o_b0->current_length += hmac_calc (sa0->integ_alg, sa0->integ_key,
 347                                              sa0->integ_key_len,
 348                                              (u8 *) o_esp0,
 349                                              o_b0->current_length -
 350                                              ip_hdr_size,
 351                                              vlib_buffer_get_current (o_b0) +
 352                                              o_b0->current_length,
 353                                              sa0->use_esn, sa0->seq_hi);
 354
 355
 356           if (PREDICT_FALSE (is_ipv6))
 357             {
 358               oh6_0->ip6.payload_length =
 359                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0) -
 360                                       sizeof (ip6_header_t));
 361             }
 362           else
 363             {
 364               oh0->ip4.length =
 365                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0));
 366               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 367             }
 368
 369           if (transport_mode)
 370             vlib_buffer_reset (o_b0);
 371
 372         trace:
 373           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 374             {
 375               if (o_b0)
 376                 {
 377                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 378                   o_b0->trace_index = i_b0->trace_index;
 379                   esp_encrypt_trace_t *tr =
 380                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 381                   tr->spi = sa0->spi;
 382                   tr->seq = sa0->seq - 1;
 383                   tr->crypto_alg = sa0->crypto_alg;
 384                   tr->integ_alg = sa0->integ_alg;
 385                 }
 386             }
 387
 388           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 389                                            to_next, n_left_to_next, o_bi0,
 390                                            next0);
 391         }
 392       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 393     }
 394   vlib_node_increment_counter (vm, esp_encrypt_node.index,
 395                                ESP_ENCRYPT_ERROR_RX_PKTS,
 396                                from_frame->n_vectors);
 397
 398 free_buffers_and_exit:
 399   if (recycle)
 400     vlib_buffer_free (vm, recycle, vec_len (recycle));
 401   vec_free (recycle);
 402   return from_frame->n_vectors;
 403 }
 404
 405
 406 /* *INDENT-OFF* */
 407 VLIB_REGISTER_NODE (esp_encrypt_node) = {
 408   .function = esp_encrypt_node_fn,
 409   .name = "esp-encrypt",
 410   .vector_size = sizeof (u32),
 411   .format_trace = format_esp_encrypt_trace,
 412   .type = VLIB_NODE_TYPE_INTERNAL,
 413
 414   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 415   .error_strings = esp_encrypt_error_strings,
 416
 417   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 418   .next_nodes = {
 419 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 420     foreach_esp_encrypt_next
 421 #undef _
 422   },
 423 };
 424 /* *INDENT-ON* */
 425
 426 VLIB_NODE_FUNCTION_MULTIARCH (esp_encrypt_node, esp_encrypt_node_fn)
 427 /*
 428  * fd.io coding-style-patch-verification: ON
 429  *
 430  * Local Variables:
 431  * eval: (c-set-style "gnu")
 432  * End:
 433  */