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