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
  27 #define foreach_ah_decrypt_next                 \
  28   _(DROP, "error-drop")                         \
  29   _(IP4_INPUT, "ip4-input")                     \
  30   _(IP6_INPUT, "ip6-input")                     \
  31   _(HANDOFF, "handoff")
  32
  33 #define _(v, s) AH_DECRYPT_NEXT_##v,
  34 typedef enum
  35 {
  36   foreach_ah_decrypt_next
  37 #undef _
  38     AH_DECRYPT_N_NEXT,
  39 } ah_decrypt_next_t;
  40
  41 typedef struct
  42 {
  43   ipsec_integ_alg_t integ_alg;
  44   u32 seq_num;
  45 } ah_decrypt_trace_t;
  46
  47 /* packet trace format function */
  48 static u8 *
  49 format_ah_decrypt_trace (u8 * s, va_list * args)
  50 {
  51   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  52   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  53   ah_decrypt_trace_t *t = va_arg (*args, ah_decrypt_trace_t *);
  54
  55   s = format (s, "ah: integrity %U seq-num %d",
  56               format_ipsec_integ_alg, t->integ_alg, t->seq_num);
  57   return s;
  58 }
  59
  60 typedef struct
  61 {
  62   union
  63   {
  64     struct
  65     {
  66       u8 hop_limit;
  67       u8 nexthdr;
  68       u32 ip_version_traffic_class_and_flow_label;
  69     };
  70
  71     struct
  72     {
  73       u8 ttl;
  74       u8 tos;
  75     };
  76   };
  77   u32 sa_index;
  78   u32 seq;
  79   u32 seq_hi;
  80   u8 icv_padding_len;
  81   u8 icv_size;
  82   u8 ip_hdr_size;
  83   i16 current_data;
  84   u8 nexthdr_cached;
  85 } ah_decrypt_packet_data_t;
  86
  87 static_always_inline void
  88 ah_process_ops (vlib_main_t * vm, vlib_node_runtime_t * node,
  89                 vnet_crypto_op_t * ops, vlib_buffer_t * b[], u16 * nexts)
  90 {
  91   u32 n_fail, n_ops = vec_len (ops);
  92   vnet_crypto_op_t *op = ops;
  93
  94   if (n_ops == 0)
  95     return;
  96
  97   n_fail = n_ops - vnet_crypto_process_ops (vm, op, n_ops);
  98
  99   while (n_fail)
 100     {
 101       ASSERT (op - ops < n_ops);
 102
 103       if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
 104         {
 105           u32 bi = op->user_data;
 106           ah_decrypt_set_next_index (
 107             b[bi], node, vm->thread_index, AH_DECRYPT_ERROR_INTEG_ERROR, bi,
 108             nexts, AH_DECRYPT_NEXT_DROP, vnet_buffer (b[bi])->ipsec.sad_index);
 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, current_sa_pkts,
 149                                              current_sa_bytes);
 150           current_sa_index = vnet_buffer (b[0])->ipsec.sad_index;
 151           sa0 = ipsec_sa_get (current_sa_index);
 152
 153           current_sa_bytes = current_sa_pkts = 0;
 154           vlib_prefetch_combined_counter (&ipsec_sa_counters,
 155                                           thread_index, current_sa_index);
 156         }
 157
 158       if (PREDICT_FALSE ((u16) ~0 == sa0->thread_index))
 159         {
 160           /* this is the first packet to use this SA, claim the SA
 161            * for this thread. this could happen simultaneously on
 162            * another thread */
 163           clib_atomic_cmp_and_swap (&sa0->thread_index, ~0,
 164                                     ipsec_sa_assign_thread (thread_index));
 165         }
 166
 167       if (PREDICT_TRUE (thread_index != sa0->thread_index))
 168         {
 169           vnet_buffer (b[0])->ipsec.thread_index = sa0->thread_index;
 170           next[0] = AH_DECRYPT_NEXT_HANDOFF;
 171           goto next;
 172         }
 173
 174       pd->sa_index = current_sa_index;
 175
 176       ih4 = vlib_buffer_get_current (b[0]);
 177       ih6 = vlib_buffer_get_current (b[0]);
 178       pd->current_data = b[0]->current_data;
 179
 180       if (is_ip6)
 181         {
 182           ip6_ext_header_t *prev = NULL;
 183           ah0 =
 184             ip6_ext_header_find (vm, b[0], ih6, IP_PROTOCOL_IPSEC_AH, &prev);
 185           pd->ip_hdr_size = sizeof (ip6_header_t);
 186           ASSERT ((u8 *) ah0 - (u8 *) ih6 == pd->ip_hdr_size);
 187         }
 188       else
 189         {
 190           if (ip4_is_fragment (ih4))
 191             {
 192               ah_decrypt_set_next_index (
 193                 b[0], node, vm->thread_index, AH_DECRYPT_ERROR_DROP_FRAGMENTS,
 194                 0, next, AH_DECRYPT_NEXT_DROP, current_sa_index);
 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           ah_decrypt_set_next_index (b[0], node, vm->thread_index,
 208                                      AH_DECRYPT_ERROR_REPLAY, 0, next,
 209                                      AH_DECRYPT_NEXT_DROP, current_sa_index);
 210           goto next;
 211         }
 212
 213       current_sa_bytes += b[0]->current_length;
 214       current_sa_pkts += 1;
 215
 216       pd->icv_size = sa0->integ_icv_size;
 217       pd->nexthdr_cached = ah0->nexthdr;
 218       if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 219         {
 220           if (PREDICT_FALSE (ipsec_sa_is_set_USE_ESN (sa0) &&
 221                              pd->current_data + b[0]->current_length
 222                              + sizeof (u32) > buffer_data_size))
 223             {
 224               ah_decrypt_set_next_index (
 225                 b[0], node, vm->thread_index, AH_DECRYPT_ERROR_NO_TAIL_SPACE,
 226                 0, next, AH_DECRYPT_NEXT_DROP, current_sa_index);
 227               goto next;
 228             }
 229
 230           vnet_crypto_op_t *op;
 231           vec_add2_aligned (ptd->integ_ops, op, 1, CLIB_CACHE_LINE_BYTES);
 232           vnet_crypto_op_init (op, sa0->integ_op_id);
 233
 234           op->src = (u8 *) ih4;
 235           op->len = b[0]->current_length;
 236           op->digest = (u8 *) ih4 - pd->icv_size;
 237           op->flags = VNET_CRYPTO_OP_FLAG_HMAC_CHECK;
 238           op->digest_len = pd->icv_size;
 239           op->key_index = sa0->integ_key_index;
 240           op->user_data = b - bufs;
 241           if (ipsec_sa_is_set_USE_ESN (sa0))
 242             {
 243               u32 seq_hi = clib_host_to_net_u32 (pd->seq_hi);
 244
 245               op->len += sizeof (seq_hi);
 246               clib_memcpy (op->src + b[0]->current_length, &seq_hi,
 247                            sizeof (seq_hi));
 248             }
 249           clib_memcpy (op->digest, ah0->auth_data, pd->icv_size);
 250           clib_memset (ah0->auth_data, 0, pd->icv_size);
 251
 252           if (is_ip6)
 253             {
 254               pd->ip_version_traffic_class_and_flow_label =
 255                 ih6->ip_version_traffic_class_and_flow_label;
 256               pd->hop_limit = ih6->hop_limit;
 257               ih6->ip_version_traffic_class_and_flow_label = 0x60;
 258               ih6->hop_limit = 0;
 259               pd->nexthdr = ah0->nexthdr;
 260               pd->icv_padding_len =
 261                 ah_calc_icv_padding_len (pd->icv_size, 1 /* is_ipv6 */ );
 262             }
 263           else
 264             {
 265               pd->tos = ih4->tos;
 266               pd->ttl = ih4->ttl;
 267               ih4->tos = 0;
 268               ih4->ttl = 0;
 269               ih4->checksum = 0;
 270               pd->icv_padding_len =
 271                 ah_calc_icv_padding_len (pd->icv_size, 0 /* is_ipv6 */ );
 272             }
 273         }
 274
 275     next:
 276       n_left -= 1;
 277       pd += 1;
 278       next += 1;
 279       b += 1;
 280     }
 281
 282   n_left = from_frame->n_vectors;
 283   next = nexts;
 284   pd = pkt_data;
 285   b = bufs;
 286
 287   vlib_node_increment_counter (vm, node->node_index, AH_DECRYPT_ERROR_RX_PKTS,
 288                                n_left);
 289   vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
 290                                    current_sa_index, current_sa_pkts,
 291                                    current_sa_bytes);
 292
 293   ah_process_ops (vm, node, ptd->integ_ops, bufs, nexts);
 294
 295   while (n_left > 0)
 296     {
 297       ip4_header_t *oh4;
 298       ip6_header_t *oh6;
 299       u64 n_lost = 0;
 300
 301       if (next[0] < AH_DECRYPT_N_NEXT)
 302         goto trace;
 303
 304       sa0 = ipsec_sa_get (pd->sa_index);
 305
 306       if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 307         {
 308           /* redo the anti-reply check. see esp_decrypt for details */
 309           if (ipsec_sa_anti_replay_and_sn_advance (sa0, pd->seq, pd->seq_hi,
 310                                                    true, NULL))
 311             {
 312               ah_decrypt_set_next_index (b[0], node, vm->thread_index,
 313                                          AH_DECRYPT_ERROR_REPLAY, 0, next,
 314                                          AH_DECRYPT_NEXT_DROP, pd->sa_index);
 315               goto trace;
 316             }
 317           n_lost = ipsec_sa_anti_replay_advance (sa0, thread_index, pd->seq,
 318                                                  pd->seq_hi);
 319           vlib_prefetch_simple_counter (
 320             &ipsec_sa_err_counters[IPSEC_SA_ERROR_LOST], thread_index,
 321             pd->sa_index);
 322         }
 323
 324       u16 ah_hdr_len = sizeof (ah_header_t) + pd->icv_size
 325         + pd->icv_padding_len;
 326       vlib_buffer_advance (b[0], pd->ip_hdr_size + ah_hdr_len);
 327       b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
 328       b[0]->flags &= ~(VNET_BUFFER_F_L4_CHECKSUM_COMPUTED |
 329                        VNET_BUFFER_F_L4_CHECKSUM_CORRECT);
 330
 331       if (PREDICT_TRUE (ipsec_sa_is_set_IS_TUNNEL (sa0)))
 332         {                       /* tunnel mode */
 333           if (PREDICT_TRUE (pd->nexthdr_cached == IP_PROTOCOL_IP_IN_IP))
 334             next[0] = AH_DECRYPT_NEXT_IP4_INPUT;
 335           else if (pd->nexthdr_cached == IP_PROTOCOL_IPV6)
 336             next[0] = AH_DECRYPT_NEXT_IP6_INPUT;
 337           else
 338             {
 339               ah_decrypt_set_next_index (b[0], node, vm->thread_index,
 340                                          AH_DECRYPT_ERROR_DECRYPTION_FAILED, 0,
 341                                          next, AH_DECRYPT_NEXT_DROP,
 342                                          pd->sa_index);
 343               goto trace;
 344             }
 345         }
 346       else
 347         {                       /* transport mode */
 348           if (is_ip6)
 349             {
 350               vlib_buffer_advance (b[0], -sizeof (ip6_header_t));
 351               oh6 = vlib_buffer_get_current (b[0]);
 352               if (ah_hdr_len >= sizeof (ip6_header_t))
 353                 clib_memcpy (oh6, b[0]->data + pd->current_data,
 354                              sizeof (ip6_header_t));
 355               else
 356                 memmove (oh6, b[0]->data + pd->current_data,
 357                          sizeof (ip6_header_t));
 358
 359               next[0] = AH_DECRYPT_NEXT_IP6_INPUT;
 360               oh6->protocol = pd->nexthdr;
 361               oh6->hop_limit = pd->hop_limit;
 362               oh6->ip_version_traffic_class_and_flow_label =
 363                 pd->ip_version_traffic_class_and_flow_label;
 364               oh6->payload_length =
 365                 clib_host_to_net_u16 (vlib_buffer_length_in_chain
 366                                       (vm, b[0]) - sizeof (ip6_header_t));
 367             }
 368           else
 369             {
 370               vlib_buffer_advance (b[0], -sizeof (ip4_header_t));
 371               oh4 = vlib_buffer_get_current (b[0]);
 372               if (ah_hdr_len >= sizeof (ip4_header_t))
 373                 clib_memcpy (oh4, b[0]->data + pd->current_data,
 374                              sizeof (ip4_header_t));
 375               else
 376                 memmove (oh4, b[0]->data + pd->current_data,
 377                          sizeof (ip4_header_t));
 378
 379               next[0] = AH_DECRYPT_NEXT_IP4_INPUT;
 380               oh4->ip_version_and_header_length = 0x45;
 381               oh4->fragment_id = 0;
 382               oh4->flags_and_fragment_offset = 0;
 383               oh4->protocol = pd->nexthdr_cached;
 384               oh4->length =
 385                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b[0]));
 386               oh4->ttl = pd->ttl;
 387               oh4->tos = pd->tos;
 388               oh4->checksum = ip4_header_checksum (oh4);
 389             }
 390         }
 391
 392       if (PREDICT_FALSE (n_lost))
 393         vlib_increment_simple_counter (
 394           &ipsec_sa_err_counters[IPSEC_SA_ERROR_LOST], thread_index,
 395           pd->sa_index, n_lost);
 396
 397       vnet_buffer (b[0])->sw_if_index[VLIB_TX] = (u32) ~ 0;
 398     trace:
 399       if (PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
 400         {
 401           sa0 = ipsec_sa_get (vnet_buffer (b[0])->ipsec.sad_index);
 402           ah_decrypt_trace_t *tr =
 403             vlib_add_trace (vm, node, b[0], sizeof (*tr));
 404           tr->integ_alg = sa0->integ_alg;
 405           tr->seq_num = pd->seq;
 406         }
 407
 408       n_left -= 1;
 409       pd += 1;
 410       next += 1;
 411       b += 1;
 412     }
 413
 414   n_left = from_frame->n_vectors;
 415   vlib_buffer_enqueue_to_next (vm, node, from, nexts, n_left);
 416
 417   return n_left;
 418 }
 419
 420 VLIB_NODE_FN (ah4_decrypt_node) (vlib_main_t * vm,
 421                                  vlib_node_runtime_t * node,
 422                                  vlib_frame_t * from_frame)
 423 {
 424   return ah_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 425 }
 426
 427 /* *INDENT-OFF* */
 428 VLIB_REGISTER_NODE (ah4_decrypt_node) = {
 429   .name = "ah4-decrypt",
 430   .vector_size = sizeof (u32),
 431   .format_trace = format_ah_decrypt_trace,
 432   .type = VLIB_NODE_TYPE_INTERNAL,
 433
 434   .n_errors = AH_DECRYPT_N_ERROR,
 435   .error_counters = ah_decrypt_error_counters,
 436
 437   .n_next_nodes = AH_DECRYPT_N_NEXT,
 438   .next_nodes = {
 439     [AH_DECRYPT_NEXT_DROP] = "ip4-drop",
 440     [AH_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
 441     [AH_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
 442     [AH_DECRYPT_NEXT_HANDOFF] = "ah4-decrypt-handoff",
 443   },
 444 };
 445 /* *INDENT-ON* */
 446
 447 VLIB_NODE_FN (ah6_decrypt_node) (vlib_main_t * vm,
 448                                  vlib_node_runtime_t * node,
 449                                  vlib_frame_t * from_frame)
 450 {
 451   return ah_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 452 }
 453
 454 /* *INDENT-OFF* */
 455 VLIB_REGISTER_NODE (ah6_decrypt_node) = {
 456   .name = "ah6-decrypt",
 457   .vector_size = sizeof (u32),
 458   .format_trace = format_ah_decrypt_trace,
 459   .type = VLIB_NODE_TYPE_INTERNAL,
 460
 461   .n_errors = AH_DECRYPT_N_ERROR,
 462   .error_counters = ah_decrypt_error_counters,
 463
 464   .n_next_nodes = AH_DECRYPT_N_NEXT,
 465   .next_nodes = {
 466     [AH_DECRYPT_NEXT_DROP] = "ip6-drop",
 467     [AH_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
 468     [AH_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
 469     [AH_DECRYPT_NEXT_HANDOFF] = "ah6-decrypt-handoff",
 470   },
 471 };
 472 /* *INDENT-ON* */
 473
 474 #ifndef CLIB_MARCH_VARIANT
 475
 476 static clib_error_t *
 477 ah_decrypt_init (vlib_main_t *vm)
 478 {
 479   ipsec_main_t *im = &ipsec_main;
 480
 481   im->ah4_dec_fq_index =
 482     vlib_frame_queue_main_init (ah4_decrypt_node.index, 0);
 483   im->ah6_dec_fq_index =
 484     vlib_frame_queue_main_init (ah6_decrypt_node.index, 0);
 485
 486   return 0;
 487 }
 488
 489 VLIB_INIT_FUNCTION (ah_decrypt_init);
 490
 491 #endif
 492
 493 /*
 494  * fd.io coding-style-patch-verification: ON
 495  *
 496  * Local Variables:
 497  * eval: (c-set-style "gnu")
 498  * End:
 499  */