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