src/vnet/ipsec/ah_decrypt.c

   1 /*
   2  * ah_decrypt.c : IPSec AH 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/ah.h>
  25 #include <vnet/ipsec/ipsec_io.h>
  26 #include <vnet/ipsec/ipsec.api_enum.h>
  27
  28 #define foreach_ah_decrypt_next                 \
  29   _(DROP, "error-drop")                         \
  30   _(IP4_INPUT, "ip4-input")                     \
  31   _(IP6_INPUT, "ip6-input")                     \
  32   _(HANDOFF, "handoff")
  33
  34 #define _(v, s) AH_DECRYPT_NEXT_##v,
  35 typedef enum
  36 {
  37   foreach_ah_decrypt_next
  38 #undef _
  39     AH_DECRYPT_N_NEXT,
  40 } ah_decrypt_next_t;
  41
  42 typedef struct
  43 {
  44   ipsec_integ_alg_t integ_alg;
  45   u32 seq_num;
  46 } ah_decrypt_trace_t;
  47
  48 /* packet trace format function */
  49 static u8 *
  50 format_ah_decrypt_trace (u8 * s, va_list * args)
  51 {
  52   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  53   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  54   ah_decrypt_trace_t *t = va_arg (*args, ah_decrypt_trace_t *);
  55
  56   s = format (s, "ah: integrity %U seq-num %d",
  57               format_ipsec_integ_alg, t->integ_alg, t->seq_num);
  58   return s;
  59 }
  60
  61 typedef struct
  62 {
  63   union
  64   {
  65     struct
  66     {
  67       u8 hop_limit;
  68       u8 nexthdr;
  69       u32 ip_version_traffic_class_and_flow_label;
  70     };
  71
  72     struct
  73     {
  74       u8 ttl;
  75       u8 tos;
  76     };
  77   };
  78   u32 sa_index;
  79   u32 seq;
  80   u32 seq_hi;
  81   u8 icv_padding_len;
  82   u8 icv_size;
  83   u8 ip_hdr_size;
  84   i16 current_data;
  85   u8 nexthdr_cached;
  86 } ah_decrypt_packet_data_t;
  87
  88 static_always_inline void
  89 ah_process_ops (vlib_main_t * vm, vlib_node_runtime_t * node,
  90                 vnet_crypto_op_t * ops, vlib_buffer_t * b[], u16 * nexts)
  91 {
  92   u32 n_fail, n_ops = vec_len (ops);
  93   vnet_crypto_op_t *op = ops;
  94
  95   if (n_ops == 0)
  96     return;
  97
  98   n_fail = n_ops - vnet_crypto_process_ops (vm, op, n_ops);
  99
 100   while (n_fail)
 101     {
 102       ASSERT (op - ops < n_ops);
 103
 104       if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
 105         {
 106           u32 bi = op->user_data;
 107           b[bi]->error = node->errors[AH_DECRYPT_ERROR_INTEG_ERROR];
 108           nexts[bi] = AH_DECRYPT_NEXT_DROP;
 109           n_fail--;
 110         }
 111       op++;
 112     }
 113 }
 114
 115 always_inline uword
 116 ah_decrypt_inline (vlib_main_t * vm,
 117                    vlib_node_runtime_t * node, vlib_frame_t * from_frame,
 118                    int is_ip6)
 119 {
 120   u32 n_left, *from;
 121   u32 thread_index = vm->thread_index;
 122   u16 buffer_data_size = vlib_buffer_get_default_data_size (vm);
 123   ah_decrypt_packet_data_t pkt_data[VLIB_FRAME_SIZE], *pd = pkt_data;
 124   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
 125   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 126   ipsec_main_t *im = &ipsec_main;
 127   ipsec_per_thread_data_t *ptd = vec_elt_at_index (im->ptd, thread_index);
 128   from = vlib_frame_vector_args (from_frame);
 129   n_left = from_frame->n_vectors;
 130   ipsec_sa_t *sa0 = 0;
 131   u32 current_sa_index = ~0, current_sa_bytes = 0, current_sa_pkts = 0;
 132
 133   clib_memset (pkt_data, 0, VLIB_FRAME_SIZE * sizeof (pkt_data[0]));
 134   vlib_get_buffers (vm, from, b, n_left);
 135   clib_memset_u16 (nexts, -1, n_left);
 136   vec_reset_length (ptd->integ_ops);
 137
 138   while (n_left > 0)
 139     {
 140       ah_header_t *ah0;
 141       ip4_header_t *ih4;
 142       ip6_header_t *ih6;
 143
 144       if (vnet_buffer (b[0])->ipsec.sad_index != current_sa_index)
 145         {
 146           if (current_sa_index != ~0)
 147             vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
 148                                              current_sa_index,
 149                                              current_sa_pkts,
 150                                              current_sa_bytes);
 151           current_sa_index = vnet_buffer (b[0])->ipsec.sad_index;
 152           sa0 = ipsec_sa_get (current_sa_index);
 153
 154           current_sa_bytes = current_sa_pkts = 0;
 155           vlib_prefetch_combined_counter (&ipsec_sa_counters,
 156                                           thread_index, current_sa_index);
 157         }
 158
 159       if (PREDICT_FALSE (~0 == sa0->thread_index))
 160         {
 161           /* this is the first packet to use this SA, claim the SA
 162            * for this thread. this could happen simultaneously on
 163            * another thread */
 164           clib_atomic_cmp_and_swap (&sa0->thread_index, ~0,
 165                                     ipsec_sa_assign_thread (thread_index));
 166         }
 167
 168       if (PREDICT_TRUE (thread_index != sa0->thread_index))
 169         {
 170           vnet_buffer (b[0])->ipsec.thread_index = sa0->thread_index;
 171           next[0] = AH_DECRYPT_NEXT_HANDOFF;
 172           goto next;
 173         }
 174
 175       pd->sa_index = current_sa_index;
 176
 177       ih4 = vlib_buffer_get_current (b[0]);
 178       ih6 = vlib_buffer_get_current (b[0]);
 179       pd->current_data = b[0]->current_data;
 180
 181       if (is_ip6)
 182         {
 183           ip6_ext_header_t *prev = NULL;
 184           ah0 =
 185             ip6_ext_header_find (vm, b[0], ih6, IP_PROTOCOL_IPSEC_AH, &prev);
 186           pd->ip_hdr_size = sizeof (ip6_header_t);
 187           ASSERT ((u8 *) ah0 - (u8 *) ih6 == pd->ip_hdr_size);
 188         }
 189       else
 190         {
 191           if (ip4_is_fragment (ih4))
 192             {
 193               b[0]->error = node->errors[AH_DECRYPT_ERROR_DROP_FRAGMENTS];
 194               next[0] = AH_DECRYPT_NEXT_DROP;
 195               goto next;
 196             }
 197           pd->ip_hdr_size = ip4_header_bytes (ih4);
 198           ah0 = (ah_header_t *) ((u8 *) ih4 + pd->ip_hdr_size);
 199         }
 200
 201       pd->seq = clib_host_to_net_u32 (ah0->seq_no);
 202
 203       /* anti-replay check */
 204       if (ipsec_sa_anti_replay_and_sn_advance (sa0, pd->seq, ~0, false,
 205                                                &pd->seq_hi))
 206         {
 207           b[0]->error = node->errors[AH_DECRYPT_ERROR_REPLAY];
 208           next[0] = AH_DECRYPT_NEXT_DROP;
 209           goto next;
 210         }
 211
 212       current_sa_bytes += b[0]->current_length;
 213       current_sa_pkts += 1;
 214
 215       pd->icv_size = sa0->integ_icv_size;
 216       pd->nexthdr_cached = ah0->nexthdr;
 217       if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 218         {
 219           if (PREDICT_FALSE (ipsec_sa_is_set_USE_ESN (sa0) &&
 220                              pd->current_data + b[0]->current_length
 221                              + sizeof (u32) > buffer_data_size))
 222             {
 223               b[0]->error = node->errors[AH_DECRYPT_ERROR_NO_TAIL_SPACE];
 224               next[0] = AH_DECRYPT_NEXT_DROP;
 225               goto next;
 226             }
 227
 228           vnet_crypto_op_t *op;
 229           vec_add2_aligned (ptd->integ_ops, op, 1, CLIB_CACHE_LINE_BYTES);
 230           vnet_crypto_op_init (op, sa0->integ_op_id);
 231
 232           op->src = (u8 *) ih4;
 233           op->len = b[0]->current_length;
 234           op->digest = (u8 *) ih4 - pd->icv_size;
 235           op->flags = VNET_CRYPTO_OP_FLAG_HMAC_CHECK;
 236           op->digest_len = pd->icv_size;
 237           op->key_index = sa0->integ_key_index;
 238           op->user_data = b - bufs;
 239           if (ipsec_sa_is_set_USE_ESN (sa0))
 240             {
 241               u32 seq_hi = clib_host_to_net_u32 (pd->seq_hi);
 242
 243               op->len += sizeof (seq_hi);
 244               clib_memcpy (op->src + b[0]->current_length, &seq_hi,
 245                            sizeof (seq_hi));
 246             }
 247           clib_memcpy (op->digest, ah0->auth_data, pd->icv_size);
 248           clib_memset (ah0->auth_data, 0, pd->icv_size);
 249
 250           if (is_ip6)
 251             {
 252               pd->ip_version_traffic_class_and_flow_label =
 253                 ih6->ip_version_traffic_class_and_flow_label;
 254               pd->hop_limit = ih6->hop_limit;
 255               ih6->ip_version_traffic_class_and_flow_label = 0x60;
 256               ih6->hop_limit = 0;
 257               pd->nexthdr = ah0->nexthdr;
 258               pd->icv_padding_len =
 259                 ah_calc_icv_padding_len (pd->icv_size, 1 /* is_ipv6 */ );
 260             }
 261           else
 262             {
 263               pd->tos = ih4->tos;
 264               pd->ttl = ih4->ttl;
 265               ih4->tos = 0;
 266               ih4->ttl = 0;
 267               ih4->checksum = 0;
 268               pd->icv_padding_len =
 269                 ah_calc_icv_padding_len (pd->icv_size, 0 /* is_ipv6 */ );
 270             }
 271         }
 272
 273     next:
 274       n_left -= 1;
 275       pd += 1;
 276       next += 1;
 277       b += 1;
 278     }
 279
 280   n_left = from_frame->n_vectors;
 281   next = nexts;
 282   pd = pkt_data;
 283   b = bufs;
 284
 285   vlib_node_increment_counter (vm, node->node_index, AH_DECRYPT_ERROR_RX_PKTS,
 286                                n_left);
 287   vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
 288                                    current_sa_index, current_sa_pkts,
 289                                    current_sa_bytes);
 290
 291   ah_process_ops (vm, node, ptd->integ_ops, bufs, nexts);
 292
 293   while (n_left > 0)
 294     {
 295       ip4_header_t *oh4;
 296       ip6_header_t *oh6;
 297       u64 n_lost = 0;
 298
 299       if (next[0] < AH_DECRYPT_N_NEXT)
 300         goto trace;
 301
 302       sa0 = ipsec_sa_get (pd->sa_index);
 303
 304       if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 305         {
 306           /* redo the anti-reply check. see esp_decrypt for details */
 307           if (ipsec_sa_anti_replay_and_sn_advance (sa0, pd->seq, pd->seq_hi,
 308                                                    true, NULL))
 309             {
 310               b[0]->error = node->errors[AH_DECRYPT_ERROR_REPLAY];
 311               next[0] = AH_DECRYPT_NEXT_DROP;
 312               goto trace;
 313             }
 314           n_lost = ipsec_sa_anti_replay_advance (sa0, thread_index, pd->seq,
 315                                                  pd->seq_hi);
 316           vlib_prefetch_simple_counter (&ipsec_sa_lost_counters, thread_index,
 317                                         pd->sa_index);
 318         }
 319
 320       u16 ah_hdr_len = sizeof (ah_header_t) + pd->icv_size
 321         + pd->icv_padding_len;
 322       vlib_buffer_advance (b[0], pd->ip_hdr_size + ah_hdr_len);
 323       b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
 324
 325       if (PREDICT_TRUE (ipsec_sa_is_set_IS_TUNNEL (sa0)))
 326         {                       /* tunnel mode */
 327           if (PREDICT_TRUE (pd->nexthdr_cached == IP_PROTOCOL_IP_IN_IP))
 328             next[0] = AH_DECRYPT_NEXT_IP4_INPUT;
 329           else if (pd->nexthdr_cached == IP_PROTOCOL_IPV6)
 330             next[0] = AH_DECRYPT_NEXT_IP6_INPUT;
 331           else
 332             {
 333               b[0]->error = node->errors[AH_DECRYPT_ERROR_DECRYPTION_FAILED];
 334               next[0] = AH_DECRYPT_NEXT_DROP;
 335               goto trace;
 336             }
 337         }
 338       else
 339         {                       /* transport mode */
 340           if (is_ip6)
 341             {
 342               vlib_buffer_advance (b[0], -sizeof (ip6_header_t));
 343               oh6 = vlib_buffer_get_current (b[0]);
 344               if (ah_hdr_len >= sizeof (ip6_header_t))
 345                 clib_memcpy (oh6, b[0]->data + pd->current_data,
 346                              sizeof (ip6_header_t));
 347               else
 348                 memmove (oh6, b[0]->data + pd->current_data,
 349                          sizeof (ip6_header_t));
 350
 351               next[0] = AH_DECRYPT_NEXT_IP6_INPUT;
 352               oh6->protocol = pd->nexthdr;
 353               oh6->hop_limit = pd->hop_limit;
 354               oh6->ip_version_traffic_class_and_flow_label =
 355                 pd->ip_version_traffic_class_and_flow_label;
 356               oh6->payload_length =
 357                 clib_host_to_net_u16 (vlib_buffer_length_in_chain
 358                                       (vm, b[0]) - sizeof (ip6_header_t));
 359             }
 360           else
 361             {
 362               vlib_buffer_advance (b[0], -sizeof (ip4_header_t));
 363               oh4 = vlib_buffer_get_current (b[0]);
 364               if (ah_hdr_len >= sizeof (ip4_header_t))
 365                 clib_memcpy (oh4, b[0]->data + pd->current_data,
 366                              sizeof (ip4_header_t));
 367               else
 368                 memmove (oh4, b[0]->data + pd->current_data,
 369                          sizeof (ip4_header_t));
 370
 371               next[0] = AH_DECRYPT_NEXT_IP4_INPUT;
 372               oh4->ip_version_and_header_length = 0x45;
 373               oh4->fragment_id = 0;
 374               oh4->flags_and_fragment_offset = 0;
 375               oh4->protocol = pd->nexthdr_cached;
 376               oh4->length =
 377                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b[0]));
 378               oh4->ttl = pd->ttl;
 379               oh4->tos = pd->tos;
 380               oh4->checksum = ip4_header_checksum (oh4);
 381             }
 382         }
 383
 384       if (PREDICT_FALSE (n_lost))
 385         vlib_increment_simple_counter (&ipsec_sa_lost_counters, thread_index,
 386                                        pd->sa_index, n_lost);
 387
 388       vnet_buffer (b[0])->sw_if_index[VLIB_TX] = (u32) ~ 0;
 389     trace:
 390       if (PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
 391         {
 392           sa0 = ipsec_sa_get (vnet_buffer (b[0])->ipsec.sad_index);
 393           ah_decrypt_trace_t *tr =
 394             vlib_add_trace (vm, node, b[0], sizeof (*tr));
 395           tr->integ_alg = sa0->integ_alg;
 396           tr->seq_num = pd->seq;
 397         }
 398
 399       n_left -= 1;
 400       pd += 1;
 401       next += 1;
 402       b += 1;
 403     }
 404
 405   n_left = from_frame->n_vectors;
 406   vlib_buffer_enqueue_to_next (vm, node, from, nexts, n_left);
 407
 408   return n_left;
 409 }
 410
 411 VLIB_NODE_FN (ah4_decrypt_node) (vlib_main_t * vm,
 412                                  vlib_node_runtime_t * node,
 413                                  vlib_frame_t * from_frame)
 414 {
 415   return ah_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 416 }
 417
 418 /* *INDENT-OFF* */
 419 VLIB_REGISTER_NODE (ah4_decrypt_node) = {
 420   .name = "ah4-decrypt",
 421   .vector_size = sizeof (u32),
 422   .format_trace = format_ah_decrypt_trace,
 423   .type = VLIB_NODE_TYPE_INTERNAL,
 424
 425   .n_errors = AH_DECRYPT_N_ERROR,
 426   .error_counters = ah_decrypt_error_counters,
 427
 428   .n_next_nodes = AH_DECRYPT_N_NEXT,
 429   .next_nodes = {
 430     [AH_DECRYPT_NEXT_DROP] = "ip4-drop",
 431     [AH_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
 432     [AH_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
 433     [AH_DECRYPT_NEXT_HANDOFF] = "ah4-decrypt-handoff",
 434   },
 435 };
 436 /* *INDENT-ON* */
 437
 438 VLIB_NODE_FN (ah6_decrypt_node) (vlib_main_t * vm,
 439                                  vlib_node_runtime_t * node,
 440                                  vlib_frame_t * from_frame)
 441 {
 442   return ah_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 443 }
 444
 445 /* *INDENT-OFF* */
 446 VLIB_REGISTER_NODE (ah6_decrypt_node) = {
 447   .name = "ah6-decrypt",
 448   .vector_size = sizeof (u32),
 449   .format_trace = format_ah_decrypt_trace,
 450   .type = VLIB_NODE_TYPE_INTERNAL,
 451
 452   .n_errors = AH_DECRYPT_N_ERROR,
 453   .error_counters = ah_decrypt_error_counters,
 454
 455   .n_next_nodes = AH_DECRYPT_N_NEXT,
 456   .next_nodes = {
 457     [AH_DECRYPT_NEXT_DROP] = "ip6-drop",
 458     [AH_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
 459     [AH_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
 460     [AH_DECRYPT_NEXT_HANDOFF] = "ah6-decrypt-handoff",
 461   },
 462 };
 463 /* *INDENT-ON* */
 464
 465 #ifndef CLIB_MARCH_VARIANT
 466
 467 static clib_error_t *
 468 ah_decrypt_init (vlib_main_t *vm)
 469 {
 470   ipsec_main_t *im = &ipsec_main;
 471
 472   im->ah4_dec_fq_index =
 473     vlib_frame_queue_main_init (ah4_decrypt_node.index, 0);
 474   im->ah6_dec_fq_index =
 475     vlib_frame_queue_main_init (ah6_decrypt_node.index, 0);
 476
 477   return 0;
 478 }
 479
 480 VLIB_INIT_FUNCTION (ah_decrypt_init);
 481
 482 #endif
 483
 484 /*
 485  * fd.io coding-style-patch-verification: ON
 486  *
 487  * Local Variables:
 488  * eval: (c-set-style "gnu")
 489  * End:
 490  */