vnet/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 #define ESP_SEQ_MAX (4294967295UL)
  26
  27 #define foreach_esp_encrypt_next                   \
  28 _(DROP, "error-drop")                              \
  29 _(IP4_INPUT, "ip4-input")                          \
  30 _(IP6_INPUT, "ip6-input")                          \
  31 _(INTERFACE_OUTPUT, "interface-output")
  32
  33 #define _(v, s) ESP_ENCRYPT_NEXT_##v,
  34 typedef enum {
  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 #define _(sym,str) ESP_ENCRYPT_ERROR_##sym,
  49   foreach_esp_encrypt_error
  50 #undef _
  51   ESP_ENCRYPT_N_ERROR,
  52 } esp_encrypt_error_t;
  53
  54 static char * esp_encrypt_error_strings[] = {
  55 #define _(sym,string) string,
  56   foreach_esp_encrypt_error
  57 #undef _
  58 };
  59
  60 vlib_node_registration_t esp_encrypt_node;
  61
  62 typedef struct {
  63   u32 spi;
  64   u32 seq;
  65   ipsec_crypto_alg_t crypto_alg;
  66   ipsec_integ_alg_t integ_alg;
  67 } esp_encrypt_trace_t;
  68
  69 /* packet trace format function */
  70 static u8 * format_esp_encrypt_trace (u8 * s, va_list * args)
  71 {
  72   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  73   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  74   esp_encrypt_trace_t * t = va_arg (*args, esp_encrypt_trace_t *);
  75
  76   s = format (s, "esp: spi %u seq %u crypto %U integrity %U",
  77               t->spi, t->seq,
  78               format_ipsec_crypto_alg, t->crypto_alg,
  79               format_ipsec_integ_alg, t->integ_alg);
  80   return s;
  81 }
  82
  83 always_inline void
  84 esp_encrypt_aes_cbc(ipsec_crypto_alg_t alg,
  85                     u8 * in,
  86                     u8 * out,
  87                     size_t in_len,
  88                     u8 * key,
  89                     u8 * iv)
  90 {
  91   esp_main_t * em = &esp_main;
  92   u32 cpu_index = os_get_cpu_number();
  93   EVP_CIPHER_CTX * ctx = &(em->per_thread_data[cpu_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(alg != em->per_thread_data[cpu_index].last_encrypt_alg)) {
 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 always_inline int
 114 esp_seq_advance (ipsec_sa_t * sa)
 115 {
 116   if (PREDICT_TRUE(sa->use_esn))
 117     {
 118       if (PREDICT_FALSE(sa->seq == ESP_SEQ_MAX))
 119         {
 120           if (PREDICT_FALSE(sa->use_anti_replay && sa->seq_hi == ESP_SEQ_MAX))
 121             return 1;
 122           sa->seq_hi++;
 123         }
 124       sa->seq++;
 125     }
 126   else
 127     {
 128       if (PREDICT_FALSE(sa->use_anti_replay && sa->seq == ESP_SEQ_MAX))
 129         return 1;
 130       sa->seq++;
 131     }
 132
 133   return 0;
 134 }
 135
 136 static uword
 137 esp_encrypt_node_fn (vlib_main_t * vm,
 138                      vlib_node_runtime_t * node,
 139                      vlib_frame_t * from_frame)
 140 {
 141   u32 n_left_from, *from, * to_next = 0, next_index;
 142   from = vlib_frame_vector_args (from_frame);
 143   n_left_from = from_frame->n_vectors;
 144   ipsec_main_t *im = &ipsec_main;
 145   u32 * recycle = 0;
 146   u32 cpu_index = os_get_cpu_number();
 147
 148   ipsec_alloc_empty_buffers(vm, im);
 149
 150   u32 * empty_buffers = im->empty_buffers[cpu_index];
 151
 152   if (PREDICT_FALSE(vec_len (empty_buffers) < n_left_from)){
 153     vlib_node_increment_counter (vm, esp_encrypt_node.index,
 154                                  ESP_ENCRYPT_ERROR_NO_BUFFER, n_left_from);
 155     clib_warning("no enough empty buffers. discarding frame");
 156     goto free_buffers_and_exit;
 157   }
 158
 159   next_index = node->cached_next_index;
 160
 161   while (n_left_from > 0)
 162     {
 163       u32 n_left_to_next;
 164
 165       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 166
 167       while (n_left_from > 0 && n_left_to_next > 0)
 168         {
 169           u32 i_bi0, o_bi0, next0;
 170           vlib_buffer_t * i_b0, *o_b0 = 0;
 171           u32 sa_index0;
 172           ipsec_sa_t * sa0;
 173           ip4_and_esp_header_t * ih0, * oh0 = 0;
 174           ip6_and_esp_header_t * ih6_0, * oh6_0 = 0;
 175           uword last_empty_buffer;
 176           esp_header_t * o_esp0;
 177           esp_footer_t *f0;
 178           u8 is_ipv6;
 179           u8 ip_hdr_size;
 180           u8 next_hdr_type;
 181           u32 ip_proto = 0;
 182           u8 transport_mode = 0;
 183
 184           i_bi0 = from[0];
 185           from += 1;
 186           n_left_from -= 1;
 187           n_left_to_next -= 1;
 188
 189           next0 = ESP_ENCRYPT_NEXT_DROP;
 190
 191           i_b0 = vlib_get_buffer (vm, i_bi0);
 192           sa_index0 = vnet_buffer(i_b0)->output_features.ipsec_sad_index;
 193           sa0 = pool_elt_at_index(im->sad, sa_index0);
 194
 195           if (PREDICT_FALSE(esp_seq_advance(sa0)))
 196             {
 197               clib_warning("sequence number counter has cycled SPI %u", sa0->spi);
 198               vlib_node_increment_counter (vm, esp_encrypt_node.index,
 199                                            ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 200               //TODO: rekey SA
 201               o_bi0 = i_bi0;
 202               goto trace;
 203             }
 204
 205           /* grab free buffer */
 206           last_empty_buffer = vec_len (empty_buffers) - 1;
 207           o_bi0 = empty_buffers[last_empty_buffer];
 208           o_b0 = vlib_get_buffer (vm, o_bi0);
 209           o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 210           o_b0->current_data = sizeof(ethernet_header_t);
 211           ih0 = vlib_buffer_get_current (i_b0);
 212           vlib_prefetch_buffer_with_index (vm, empty_buffers[last_empty_buffer-1], STORE);
 213           _vec_len (empty_buffers) = last_empty_buffer;
 214           to_next[0] = o_bi0;
 215           to_next += 1;
 216
 217           /* add old buffer to the recycle list */
 218           vec_add1(recycle, i_bi0);
 219
 220           /* is ipv6 */
 221           if (PREDICT_FALSE((ih0->ip4.ip_version_and_header_length & 0xF0 ) == 0x60))
 222             {
 223               is_ipv6 = 1;
 224               ih6_0 = vlib_buffer_get_current (i_b0);
 225               ip_hdr_size = sizeof(ip6_header_t);
 226               next_hdr_type = IP_PROTOCOL_IPV6;
 227               oh6_0 = vlib_buffer_get_current (o_b0);
 228               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof(ip6_header_t);
 229
 230               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 231                   ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 232               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 233               oh6_0->ip6.hop_limit = 254;
 234               oh6_0->ip6.src_address.as_u64[0] = ih6_0->ip6.src_address.as_u64[0];
 235               oh6_0->ip6.src_address.as_u64[1] = ih6_0->ip6.src_address.as_u64[1];
 236               oh6_0->ip6.dst_address.as_u64[0] = ih6_0->ip6.dst_address.as_u64[0];
 237               oh6_0->ip6.dst_address.as_u64[1] = ih6_0->ip6.dst_address.as_u64[1];
 238               oh6_0->esp.spi = clib_net_to_host_u32(sa0->spi);
 239               oh6_0->esp.seq = clib_net_to_host_u32(sa0->seq);
 240               ip_proto = ih6_0->ip6.protocol;
 241             }
 242           else
 243             {
 244               is_ipv6 = 0;
 245               ip_hdr_size = sizeof(ip4_header_t);
 246               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 247               oh0 = vlib_buffer_get_current (o_b0);
 248               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof(ip4_header_t);
 249
 250               oh0->ip4.ip_version_and_header_length = 0x45;
 251               oh0->ip4.tos = ih0->ip4.tos;
 252               oh0->ip4.fragment_id = 0;
 253               oh0->ip4.flags_and_fragment_offset = 0;
 254               oh0->ip4.ttl = 254;
 255               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 256               oh0->ip4.src_address.as_u32 = ih0->ip4.src_address.as_u32;
 257               oh0->ip4.dst_address.as_u32 = ih0->ip4.dst_address.as_u32;
 258               oh0->esp.spi = clib_net_to_host_u32(sa0->spi);
 259               oh0->esp.seq = clib_net_to_host_u32(sa0->seq);
 260               ip_proto = ih0->ip4.protocol;
 261             }
 262
 263           if (PREDICT_TRUE(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               /* in tunnel mode send it back to FIB */
 269               next0 = ESP_ENCRYPT_NEXT_IP4_INPUT;
 270               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32)~0;
 271             }
 272           else if(sa0->is_tunnel && sa0->is_tunnel_ip6)
 273             {
 274               oh6_0->ip6.src_address.as_u64[0] = sa0->tunnel_src_addr.ip6.as_u64[0];
 275               oh6_0->ip6.src_address.as_u64[1] = sa0->tunnel_src_addr.ip6.as_u64[1];
 276               oh6_0->ip6.dst_address.as_u64[0] = sa0->tunnel_dst_addr.ip6.as_u64[0];
 277               oh6_0->ip6.dst_address.as_u64[1] = sa0->tunnel_dst_addr.ip6.as_u64[1];
 278
 279               /* in tunnel mode send it back to FIB */
 280               next0 = ESP_ENCRYPT_NEXT_IP6_INPUT;
 281               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32)~0;
 282             }
 283           else
 284             {
 285               transport_mode = 1;
 286               ethernet_header_t *ieh0, *oeh0;
 287               ieh0 = (ethernet_header_t *) i_b0->data;
 288               oeh0 = (ethernet_header_t *) o_b0->data;
 289               clib_memcpy (oeh0, ieh0, sizeof(ethernet_header_t));
 290               vlib_buffer_advance(i_b0, ip_hdr_size);
 291               next_hdr_type = ip_proto;
 292               next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 293               o_b0->flags |= BUFFER_OUTPUT_FEAT_DONE;
 294               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 295                 vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 296               vnet_buffer(o_b0)->output_features.bitmap =
 297                 vnet_buffer(i_b0)->output_features.bitmap;
 298             }
 299
 300           ASSERT(sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 301
 302           if (PREDICT_TRUE(sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE)) {
 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 = 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) + ip_hdr_size +
 331                    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) + IV_SIZE,
 337                                 BLOCK_SIZE * blocks,
 338                                 sa0->crypto_key,
 339                                 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 - ip_hdr_size,
 346                                             vlib_buffer_get_current (o_b0) +
 347                                             o_b0->current_length,
 348                                             sa0->use_esn,
 349                                             sa0->seq_hi);
 350
 351
 352           if (PREDICT_FALSE(is_ipv6))
 353             {
 354               oh6_0->ip6.payload_length = clib_host_to_net_u16 (
 355                   vlib_buffer_length_in_chain (vm, o_b0) - sizeof(ip6_header_t));
 356             }
 357           else
 358             {
 359               oh0->ip4.length = clib_host_to_net_u16 (
 360                   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             if (o_b0) {
 370               o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 371               o_b0->trace_index = i_b0->trace_index;
 372             }
 373             esp_encrypt_trace_t *tr = vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 374             tr->spi = sa0->spi;
 375             tr->seq = sa0->seq - 1;
 376             tr->crypto_alg = sa0->crypto_alg;
 377             tr->integ_alg = sa0->integ_alg;
 378           }
 379
 380           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 381               to_next, n_left_to_next, o_bi0, next0);
 382         }
 383       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 384     }
 385   vlib_node_increment_counter (vm, esp_encrypt_node.index,
 386                                ESP_ENCRYPT_ERROR_RX_PKTS,
 387                                from_frame->n_vectors);
 388
 389 free_buffers_and_exit:
 390   vlib_buffer_free (vm, recycle, vec_len(recycle));
 391   vec_free(recycle);
 392   return from_frame->n_vectors;
 393 }
 394
 395
 396 VLIB_REGISTER_NODE (esp_encrypt_node) = {
 397   .function = esp_encrypt_node_fn,
 398   .name = "esp-encrypt",
 399   .vector_size = sizeof (u32),
 400   .format_trace = format_esp_encrypt_trace,
 401   .type = VLIB_NODE_TYPE_INTERNAL,
 402
 403   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 404   .error_strings = esp_encrypt_error_strings,
 405
 406   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 407   .next_nodes = {
 408 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 409     foreach_esp_encrypt_next
 410 #undef _
 411   },
 412 };
 413
 414 VLIB_NODE_FUNCTION_MULTIARCH (esp_encrypt_node, esp_encrypt_node_fn)
 415