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   EVP_CIPHER_CTX * ctx = &(em->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->last_encrytp_alg)) {
 102     cipher = em->esp_crypto_algs[alg].type;
 103     em->last_encrytp_alg = alg;
 104   }
 105
 106   EVP_EncryptInit_ex(ctx, cipher, NULL, key, iv);
 107
 108   EVP_EncryptUpdate(ctx, out, &out_len, in, in_len);
 109   EVP_EncryptFinal_ex(ctx, out + out_len, &out_len);
 110 }
 111
 112 always_inline int
 113 esp_seq_advance (ipsec_sa_t * sa)
 114 {
 115   if (PREDICT_TRUE(sa->use_esn))
 116     {
 117       if (PREDICT_FALSE(sa->seq == ESP_SEQ_MAX))
 118         {
 119           if (PREDICT_FALSE(sa->use_anti_replay && sa->seq_hi == ESP_SEQ_MAX))
 120             return 1;
 121           sa->seq_hi++;
 122         }
 123       sa->seq++;
 124     }
 125   else
 126     {
 127       if (PREDICT_FALSE(sa->use_anti_replay && sa->seq == ESP_SEQ_MAX))
 128         return 1;
 129       sa->seq++;
 130     }
 131
 132   return 0;
 133 }
 134
 135 static uword
 136 esp_encrypt_node_fn (vlib_main_t * vm,
 137                      vlib_node_runtime_t * node,
 138                      vlib_frame_t * from_frame)
 139 {
 140   u32 n_left_from, *from, * to_next = 0, next_index;
 141   from = vlib_frame_vector_args (from_frame);
 142   n_left_from = from_frame->n_vectors;
 143   ipsec_main_t *im = &ipsec_main;
 144   u32 * recycle = 0;
 145
 146   ipsec_alloc_empty_buffers(vm, im);
 147
 148   if (PREDICT_FALSE(vec_len (im->empty_buffers) < n_left_from)){
 149     vlib_node_increment_counter (vm, esp_encrypt_node.index,
 150                                  ESP_ENCRYPT_ERROR_NO_BUFFER, n_left_from);
 151     clib_warning("no enough empty buffers. discarding frame");
 152     goto free_buffers_and_exit;
 153   }
 154
 155   next_index = node->cached_next_index;
 156
 157   while (n_left_from > 0)
 158     {
 159       u32 n_left_to_next;
 160
 161       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 162
 163       while (n_left_from > 0 && n_left_to_next > 0)
 164         {
 165           u32 i_bi0, o_bi0, next0;
 166           vlib_buffer_t * i_b0, *o_b0 = 0;
 167           u32 sa_index0;
 168           ipsec_sa_t * sa0;
 169           ip4_and_esp_header_t * ih0, * oh0 = 0;
 170           ip6_and_esp_header_t * ih6_0, * oh6_0 = 0;
 171           uword last_empty_buffer;
 172           esp_header_t * o_esp0;
 173           esp_footer_t *f0;
 174           u8 is_ipv6;
 175           u8 ip_hdr_size;
 176           u8 next_hdr_type;
 177
 178           i_bi0 = from[0];
 179           from += 1;
 180           n_left_from -= 1;
 181           n_left_to_next -= 1;
 182
 183           next0 = ESP_ENCRYPT_NEXT_DROP;
 184
 185           i_b0 = vlib_get_buffer (vm, i_bi0);
 186           sa_index0 = vnet_buffer(i_b0)->output_features.ipsec_sad_index;
 187           sa0 = pool_elt_at_index(im->sad, sa_index0);
 188
 189           if (PREDICT_FALSE(esp_seq_advance(sa0)))
 190             {
 191               clib_warning("sequence number counter has cycled SPI %u", sa0->spi);
 192               vlib_node_increment_counter (vm, esp_encrypt_node.index,
 193                                            ESP_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 194               //TODO: rekey SA
 195               o_bi0 = i_bi0;
 196               goto trace;
 197             }
 198
 199           /* grab free buffer */
 200           last_empty_buffer = vec_len (im->empty_buffers) - 1;
 201           o_bi0 = im->empty_buffers[last_empty_buffer];
 202           o_b0 = vlib_get_buffer (vm, o_bi0);
 203           o_b0->current_data = sizeof(ethernet_header_t);
 204           ih0 = vlib_buffer_get_current (i_b0);
 205           vlib_prefetch_buffer_with_index (vm, im->empty_buffers[last_empty_buffer-1], STORE);
 206           _vec_len (im->empty_buffers) = last_empty_buffer;
 207           to_next[0] = o_bi0;
 208           to_next += 1;
 209
 210           /* add old buffer to the recycle list */
 211           vec_add1(recycle, i_bi0);
 212
 213           /* is ipv6 */
 214           if (PREDICT_FALSE((ih0->ip4.ip_version_and_header_length & 0xF0 ) == 0x60))
 215             {
 216               is_ipv6 = 1;
 217               ih6_0 = vlib_buffer_get_current (i_b0);
 218               ip_hdr_size = sizeof(ip6_header_t);
 219               next_hdr_type = IP_PROTOCOL_IPV6;
 220               oh6_0 = vlib_buffer_get_current (o_b0);
 221               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof(ip6_header_t);
 222
 223               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 224                   ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 225               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_ESP;
 226               oh6_0->ip6.hop_limit = 254;
 227               oh6_0->esp.spi = clib_net_to_host_u32(sa0->spi);
 228               oh6_0->esp.seq = clib_net_to_host_u32(sa0->seq);
 229             }
 230           else
 231             {
 232               is_ipv6 = 0;
 233               ip_hdr_size = sizeof(ip4_header_t);
 234               next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 235               oh0 = vlib_buffer_get_current (o_b0);
 236               o_esp0 = vlib_buffer_get_current (o_b0) + sizeof(ip4_header_t);
 237
 238               oh0->ip4.ip_version_and_header_length = 0x45;
 239               oh0->ip4.tos = ih0->ip4.tos;
 240               oh0->ip4.fragment_id = 0;
 241               oh0->ip4.flags_and_fragment_offset = 0;
 242               oh0->ip4.ttl = 254;
 243               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_ESP;
 244               oh0->esp.spi = clib_net_to_host_u32(sa0->spi);
 245               oh0->esp.seq = clib_net_to_host_u32(sa0->seq);
 246             }
 247
 248           if (PREDICT_TRUE(sa0->is_tunnel && !sa0->is_tunnel_ip6))
 249             {
 250               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 251               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 252
 253               /* in tunnel mode send it back to FIB */
 254               next0 = ESP_ENCRYPT_NEXT_IP4_INPUT;
 255               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32)~0;
 256             }
 257           else if(sa0->is_tunnel && sa0->is_tunnel_ip6)
 258             {
 259               oh6_0->ip6.src_address.as_u64[0] = sa0->tunnel_src_addr.ip6.as_u64[0];
 260               oh6_0->ip6.src_address.as_u64[1] = sa0->tunnel_src_addr.ip6.as_u64[1];
 261               oh6_0->ip6.dst_address.as_u64[0] = sa0->tunnel_dst_addr.ip6.as_u64[0];
 262               oh6_0->ip6.dst_address.as_u64[1] = sa0->tunnel_dst_addr.ip6.as_u64[1];
 263
 264               /* in tunnel mode send it back to FIB */
 265               next0 = ESP_ENCRYPT_NEXT_IP6_INPUT;
 266               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32)~0;
 267             }
 268           else
 269             {
 270               next0 = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 271               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] =
 272                 vnet_buffer (i_b0)->sw_if_index[VLIB_TX];
 273             }
 274
 275           ASSERT(sa0->crypto_alg < IPSEC_CRYPTO_N_ALG);
 276
 277           if (PREDICT_TRUE(sa0->crypto_alg != IPSEC_CRYPTO_ALG_NONE)) {
 278
 279             const int BLOCK_SIZE = 16;
 280             const int IV_SIZE = 16;
 281             int blocks = 1 + (i_b0->current_length + 1) / BLOCK_SIZE;
 282
 283             /* pad packet in input buffer */
 284             u8 pad_bytes = BLOCK_SIZE * blocks - 2 - i_b0->current_length;
 285             u8 i;
 286             u8 * padding = vlib_buffer_get_current (i_b0) + i_b0->current_length;
 287             i_b0->current_length = BLOCK_SIZE * blocks;
 288             for (i = 0; i < pad_bytes; ++i)
 289               {
 290                 padding[i] = i + 1;
 291               }
 292             f0 = vlib_buffer_get_current (i_b0) + i_b0->current_length - 2;
 293             f0->pad_length = pad_bytes;
 294             f0->next_header = next_hdr_type;
 295
 296             o_b0->current_length = ip_hdr_size + sizeof(esp_header_t) +
 297                   BLOCK_SIZE * blocks + IV_SIZE;
 298
 299             vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 300               vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 301             o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 302
 303             u8 iv[16];
 304             RAND_bytes(iv, sizeof(iv));
 305
 306             memcpy((u8 *) vlib_buffer_get_current (o_b0) + ip_hdr_size +
 307                    sizeof(esp_header_t), iv, 16 );
 308
 309             esp_encrypt_aes_cbc(sa0->crypto_alg,
 310                                 (u8 *) vlib_buffer_get_current (i_b0),
 311                                 (u8 *) vlib_buffer_get_current (o_b0) +
 312                                   ip_hdr_size + sizeof(esp_header_t) + IV_SIZE,
 313                                 BLOCK_SIZE * blocks,
 314                                 sa0->crypto_key,
 315                                 iv);
 316           }
 317
 318           o_b0->current_length += hmac_calc(sa0->integ_alg, sa0->integ_key,
 319                                             sa0->integ_key_len,
 320                                             (u8 *) o_esp0,
 321                                             o_b0->current_length - ip_hdr_size,
 322                                             vlib_buffer_get_current (o_b0) +
 323                                             o_b0->current_length,
 324                                             sa0->use_esn,
 325                                             sa0->seq_hi);
 326
 327
 328           if (PREDICT_FALSE(is_ipv6))
 329             {
 330               oh6_0->ip6.payload_length = clib_host_to_net_u16 (
 331                   vlib_buffer_length_in_chain (vm, o_b0) - sizeof(ip6_header_t));
 332             }
 333           else
 334             {
 335               oh0->ip4.length = clib_host_to_net_u16 (
 336                   vlib_buffer_length_in_chain (vm, o_b0));
 337               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 338             }
 339
 340 trace:
 341           if (PREDICT_FALSE(i_b0->flags & VLIB_BUFFER_IS_TRACED)) {
 342             if (o_b0) {
 343               o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 344               o_b0->trace_index = i_b0->trace_index;
 345             }
 346             esp_encrypt_trace_t *tr = vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 347             tr->spi = sa0->spi;
 348             tr->seq = sa0->seq - 1;
 349             tr->crypto_alg = sa0->crypto_alg;
 350             tr->integ_alg = sa0->integ_alg;
 351           }
 352
 353           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 354               to_next, n_left_to_next, o_bi0, next0);
 355         }
 356       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 357     }
 358   vlib_node_increment_counter (vm, esp_encrypt_node.index,
 359                                ESP_ENCRYPT_ERROR_RX_PKTS,
 360                                from_frame->n_vectors);
 361
 362 free_buffers_and_exit:
 363   vlib_buffer_free (vm, recycle, vec_len(recycle));
 364   vec_free(recycle);
 365   return from_frame->n_vectors;
 366 }
 367
 368
 369 VLIB_REGISTER_NODE (esp_encrypt_node) = {
 370   .function = esp_encrypt_node_fn,
 371   .name = "esp-encrypt",
 372   .vector_size = sizeof (u32),
 373   .format_trace = format_esp_encrypt_trace,
 374   .type = VLIB_NODE_TYPE_INTERNAL,
 375
 376   .n_errors = ARRAY_LEN(esp_encrypt_error_strings),
 377   .error_strings = esp_encrypt_error_strings,
 378
 379   .n_next_nodes = ESP_ENCRYPT_N_NEXT,
 380   .next_nodes = {
 381 #define _(s,n) [ESP_ENCRYPT_NEXT_##s] = n,
 382     foreach_esp_encrypt_next
 383 #undef _
 384   },
 385 };
 386