src/vnet/ipsec/esp_decrypt.c

   1 /*
   2  * esp_decrypt.c : IPSec ESP decrypt 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 #include <vnet/ipsec/ipsec_io.h>
  25
  26 #define foreach_esp_decrypt_next                \
  27 _(DROP, "error-drop")                           \
  28 _(IP4_INPUT, "ip4-input-no-checksum")           \
  29 _(IP6_INPUT, "ip6-input")                       \
  30 _(IPSEC_GRE_INPUT, "ipsec-gre-input")
  31
  32 #define _(v, s) ESP_DECRYPT_NEXT_##v,
  33 typedef enum
  34 {
  35   foreach_esp_decrypt_next
  36 #undef _
  37     ESP_DECRYPT_N_NEXT,
  38 } esp_decrypt_next_t;
  39
  40
  41 #define foreach_esp_decrypt_error                   \
  42  _(RX_PKTS, "ESP pkts received")                    \
  43  _(NO_BUFFER, "No buffer (packed dropped)")         \
  44  _(DECRYPTION_FAILED, "ESP decryption failed")      \
  45  _(INTEG_ERROR, "Integrity check failed")           \
  46  _(REPLAY, "SA replayed packet")                    \
  47  _(NOT_IP, "Not IP packet (dropped)")
  48
  49
  50 typedef enum
  51 {
  52 #define _(sym,str) ESP_DECRYPT_ERROR_##sym,
  53   foreach_esp_decrypt_error
  54 #undef _
  55     ESP_DECRYPT_N_ERROR,
  56 } esp_decrypt_error_t;
  57
  58 static char *esp_decrypt_error_strings[] = {
  59 #define _(sym,string) string,
  60   foreach_esp_decrypt_error
  61 #undef _
  62 };
  63
  64 typedef struct
  65 {
  66   ipsec_crypto_alg_t crypto_alg;
  67   ipsec_integ_alg_t integ_alg;
  68 } esp_decrypt_trace_t;
  69
  70 /* packet trace format function */
  71 static u8 *
  72 format_esp_decrypt_trace (u8 * s, va_list * args)
  73 {
  74   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  75   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  76   esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *);
  77
  78   s = format (s, "esp: crypto %U integrity %U",
  79               format_ipsec_crypto_alg, t->crypto_alg,
  80               format_ipsec_integ_alg, t->integ_alg);
  81   return s;
  82 }
  83
  84 always_inline void
  85 esp_decrypt_cbc (vlib_main_t * vm, ipsec_sa_t * sa,
  86                  u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
  87 {
  88   vnet_crypto_op_t _op, *op = &_op;
  89
  90
  91   if (PREDICT_FALSE (sa->crypto_dec_op_type == VNET_CRYPTO_OP_NONE))
  92     return;
  93
  94   op->op = sa->crypto_dec_op_type;
  95   op->iv = iv;
  96   op->src = in;
  97   op->dst = out;
  98   op->len = in_len;
  99   op->key = key;
 100
 101   vnet_crypto_process_ops (vm, op, 1);
 102 }
 103
 104 always_inline uword
 105 esp_decrypt_inline (vlib_main_t * vm,
 106                     vlib_node_runtime_t * node, vlib_frame_t * from_frame,
 107                     int is_ip6)
 108 {
 109   ipsec_main_t *im = &ipsec_main;
 110   u32 *from = vlib_frame_vector_args (from_frame);
 111   u32 n_left_from = from_frame->n_vectors;
 112   u32 new_bufs[VLIB_FRAME_SIZE];
 113   vlib_buffer_t *i_bufs[VLIB_FRAME_SIZE], **ib = i_bufs;
 114   vlib_buffer_t *o_bufs[VLIB_FRAME_SIZE], **ob = o_bufs;
 115   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 116   u32 n_alloc, thread_index = vm->thread_index;
 117
 118   n_alloc = vlib_buffer_alloc (vm, new_bufs, n_left_from);
 119   if (n_alloc != n_left_from)
 120     {
 121       vlib_node_increment_counter (vm, node->node_index,
 122                                    ESP_DECRYPT_ERROR_NO_BUFFER,
 123                                    n_left_from - n_alloc);
 124       if (n_alloc == 0)
 125         goto done;
 126       n_left_from = n_alloc;
 127     }
 128
 129   vlib_get_buffers (vm, from, ib, n_left_from);
 130   vlib_get_buffers (vm, new_bufs, ob, n_left_from);
 131
 132   while (n_left_from > 0)
 133     {
 134       esp_header_t *esp0;
 135       ipsec_sa_t *sa0;
 136       u32 sa_index0 = ~0;
 137       ip4_header_t *ih4 = 0, *oh4 = 0;
 138       ip6_header_t *ih6 = 0, *oh6 = 0;
 139       u8 tunnel_mode = 1;
 140
 141       next[0] = ESP_DECRYPT_NEXT_DROP;
 142
 143       esp0 = vlib_buffer_get_current (ib[0]);
 144       sa_index0 = vnet_buffer (ib[0])->ipsec.sad_index;
 145       sa0 = pool_elt_at_index (im->sad, sa_index0);
 146
 147       /* anti-replay check */
 148       if (ipsec_sa_anti_replay_check (sa0, &esp0->seq))
 149         {
 150           u32 tmp, off = n_alloc - n_left_from;
 151           /* send original packet to drop node */
 152           tmp = from[off];
 153           from[off] = new_bufs[off];
 154           new_bufs[off] = tmp;
 155           ib[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
 156           next[0] = ESP_DECRYPT_NEXT_DROP;
 157           goto trace;
 158         }
 159
 160       vlib_increment_combined_counter
 161         (&ipsec_sa_counters, thread_index, sa_index0,
 162          1, ib[0]->current_length);
 163
 164       if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 165         {
 166           u8 sig[64];
 167           int icv_size = sa0->integ_trunc_size;
 168           clib_memset (sig, 0, sizeof (sig));
 169           u8 *icv = vlib_buffer_get_current (ib[0]) + ib[0]->current_length -
 170             icv_size;
 171           ib[0]->current_length -= icv_size;
 172
 173           hmac_calc (vm, sa0, (u8 *) esp0, ib[0]->current_length, sig);
 174
 175           if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
 176             {
 177               u32 tmp, off = n_alloc - n_left_from;
 178               /* send original packet to drop node */
 179               tmp = from[off];
 180               from[off] = new_bufs[off];
 181               new_bufs[off] = tmp;
 182               ib[0]->error = node->errors[ESP_DECRYPT_ERROR_INTEG_ERROR];
 183               next[0] = ESP_DECRYPT_NEXT_DROP;
 184               goto trace;
 185             }
 186         }
 187
 188       ipsec_sa_anti_replay_advance (sa0, &esp0->seq);
 189
 190       if ((sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
 191            sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) ||
 192           (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_DES_CBC &&
 193            sa0->crypto_alg <= IPSEC_CRYPTO_ALG_3DES_CBC))
 194         {
 195           const int BLOCK_SIZE = sa0->crypto_block_size;
 196           const int IV_SIZE = sa0->crypto_block_size;
 197           esp_footer_t *f0;
 198           u8 ip_hdr_size = 0;
 199
 200           int blocks =
 201             (ib[0]->current_length - sizeof (esp_header_t) -
 202              IV_SIZE) / BLOCK_SIZE;
 203
 204           ob[0]->current_data = sizeof (ethernet_header_t);
 205
 206           /* transport mode */
 207           if (PREDICT_FALSE (!ipsec_sa_is_set_IS_TUNNEL (sa0) &&
 208                              !ipsec_sa_is_set_IS_TUNNEL_V6 (sa0)))
 209             {
 210               tunnel_mode = 0;
 211
 212               if (is_ip6)
 213                 {
 214                   ip_hdr_size = sizeof (ip6_header_t);
 215                   ih6 = (ip6_header_t *) ((u8 *) esp0 - ip_hdr_size);
 216                   oh6 = vlib_buffer_get_current (ob[0]);
 217                 }
 218               else
 219                 {
 220                   ip_hdr_size = sizeof (ip4_header_t);
 221                   if (ipsec_sa_is_set_UDP_ENCAP (sa0))
 222                     ih4 = (ip4_header_t *) ((u8 *) esp0 - ip_hdr_size -
 223                                             sizeof (udp_header_t));
 224                   else
 225                     ih4 = (ip4_header_t *) ((u8 *) esp0 - ip_hdr_size);
 226                   oh4 = vlib_buffer_get_current (ob[0]);
 227                 }
 228             }
 229
 230           esp_decrypt_cbc (vm, sa0, esp0->data + IV_SIZE,
 231                            (u8 *) vlib_buffer_get_current (ob[0]) +
 232                            ip_hdr_size, BLOCK_SIZE * blocks,
 233                            sa0->crypto_key.data, esp0->data);
 234
 235           ob[0]->current_length = (blocks * BLOCK_SIZE) - 2 + ip_hdr_size;
 236           ob[0]->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 237           f0 = (esp_footer_t *) ((u8 *) vlib_buffer_get_current (ob[0]) +
 238                                  ob[0]->current_length);
 239           ob[0]->current_length -= f0->pad_length;
 240
 241           /* tunnel mode */
 242           if (PREDICT_TRUE (tunnel_mode))
 243             {
 244               if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
 245                 {
 246                   next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
 247                   oh4 = vlib_buffer_get_current (ob[0]);
 248                 }
 249               else if (f0->next_header == IP_PROTOCOL_IPV6)
 250                 next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
 251               else
 252                 {
 253                   vlib_node_increment_counter (vm, node->node_index,
 254                                                ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
 255                                                1);
 256                   ob[0] = 0;
 257                   goto trace;
 258                 }
 259             }
 260           /* transport mode */
 261           else
 262             {
 263               u32 len = vlib_buffer_length_in_chain (vm, ob[0]);
 264               if (is_ip6)
 265                 {
 266                   next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
 267                   oh6->ip_version_traffic_class_and_flow_label =
 268                     ih6->ip_version_traffic_class_and_flow_label;
 269                   oh6->protocol = f0->next_header;
 270                   oh6->hop_limit = ih6->hop_limit;
 271                   oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
 272                   oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
 273                   oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
 274                   oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
 275                   len -= sizeof (ip6_header_t);
 276                   oh6->payload_length = clib_host_to_net_u16 (len);
 277                 }
 278               else
 279                 {
 280                   next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
 281                   oh4->ip_version_and_header_length = 0x45;
 282                   oh4->tos = ih4->tos;
 283                   oh4->fragment_id = 0;
 284                   oh4->flags_and_fragment_offset = 0;
 285                   oh4->ttl = ih4->ttl;
 286                   oh4->protocol = f0->next_header;
 287                   oh4->src_address.as_u32 = ih4->src_address.as_u32;
 288                   oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
 289                   oh4->length = clib_host_to_net_u16 (len);
 290                   oh4->checksum = ip4_header_checksum (oh4);
 291                 }
 292             }
 293
 294           /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 295           if (PREDICT_FALSE
 296               ((vnet_buffer (ib[0])->ipsec.flags) &
 297                IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 298             next[0] = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 299
 300           vnet_buffer (ob[0])->sw_if_index[VLIB_TX] = (u32) ~ 0;
 301           vnet_buffer (ob[0])->sw_if_index[VLIB_RX] =
 302             vnet_buffer (ib[0])->sw_if_index[VLIB_RX];
 303         }
 304
 305     trace:
 306       if (PREDICT_FALSE (ib[0]->flags & VLIB_BUFFER_IS_TRACED))
 307         {
 308           if (ob[0])
 309             {
 310               ob[0]->flags |= VLIB_BUFFER_IS_TRACED;
 311               ob[0]->trace_index = ib[0]->trace_index;
 312               esp_decrypt_trace_t *tr =
 313                 vlib_add_trace (vm, node, ob[0], sizeof (*tr));
 314               tr->crypto_alg = sa0->crypto_alg;
 315               tr->integ_alg = sa0->integ_alg;
 316             }
 317         }
 318
 319       /* next */
 320       n_left_from -= 1;
 321       ib += 1;
 322       ob += 1;
 323       next += 1;
 324     }
 325
 326   vlib_node_increment_counter (vm, node->node_index,
 327                                ESP_DECRYPT_ERROR_RX_PKTS, n_alloc);
 328
 329   vlib_buffer_enqueue_to_next (vm, node, new_bufs, nexts, n_alloc);
 330 done:
 331   vlib_buffer_free (vm, from, from_frame->n_vectors);
 332   return n_alloc;
 333 }
 334
 335 VLIB_NODE_FN (esp4_decrypt_node) (vlib_main_t * vm,
 336                                   vlib_node_runtime_t * node,
 337                                   vlib_frame_t * from_frame)
 338 {
 339   return esp_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 340 }
 341
 342 /* *INDENT-OFF* */
 343 VLIB_REGISTER_NODE (esp4_decrypt_node) = {
 344   .name = "esp4-decrypt",
 345   .vector_size = sizeof (u32),
 346   .format_trace = format_esp_decrypt_trace,
 347   .type = VLIB_NODE_TYPE_INTERNAL,
 348
 349   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 350   .error_strings = esp_decrypt_error_strings,
 351
 352   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 353   .next_nodes = {
 354 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 355     foreach_esp_decrypt_next
 356 #undef _
 357   },
 358 };
 359 /* *INDENT-ON* */
 360
 361 VLIB_NODE_FN (esp6_decrypt_node) (vlib_main_t * vm,
 362                                   vlib_node_runtime_t * node,
 363                                   vlib_frame_t * from_frame)
 364 {
 365   return esp_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 366 }
 367
 368 /* *INDENT-OFF* */
 369 VLIB_REGISTER_NODE (esp6_decrypt_node) = {
 370   .name = "esp6-decrypt",
 371   .vector_size = sizeof (u32),
 372   .format_trace = format_esp_decrypt_trace,
 373   .type = VLIB_NODE_TYPE_INTERNAL,
 374
 375   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 376   .error_strings = esp_decrypt_error_strings,
 377
 378   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 379   .next_nodes = {
 380 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 381     foreach_esp_decrypt_next
 382 #undef _
 383   },
 384 };
 385 /* *INDENT-ON* */
 386
 387 /*
 388  * fd.io coding-style-patch-verification: ON
 389  *
 390  * Local Variables:
 391  * eval: (c-set-style "gnu")
 392  * End:
 393  */