src/vnet/ipsec/ipsec_tun_in.c

   1 /*
   2  * ipsec_tun_protect_in.c : IPSec interface input 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 #include <vnet/ipsec/ipsec_punt.h>
  26 #include <vnet/ipsec/ipsec_tun.h>
  27 #include <vnet/ip/ip4_input.h>
  28
  29 /* Statistics (not really errors) */
  30 #define foreach_ipsec_tun_protect_input_error                     \
  31   _(RX, "good packets received")                                  \
  32   _(DISABLED, "ipsec packets received on disabled interface")     \
  33   _(NO_TUNNEL, "no matching tunnel")                              \
  34   _(TUNNEL_MISMATCH, "SPI-tunnel mismatch")                       \
  35   _(NAT_KEEPALIVE, "NAT Keepalive")                               \
  36   _(TOO_SHORT, "Too Short")                                       \
  37   _(SPI_0, "SPI 0")
  38
  39 static char *ipsec_tun_protect_input_error_strings[] = {
  40 #define _(sym,string) string,
  41   foreach_ipsec_tun_protect_input_error
  42 #undef _
  43 };
  44
  45 typedef enum
  46 {
  47 #define _(sym,str) IPSEC_TUN_PROTECT_INPUT_ERROR_##sym,
  48   foreach_ipsec_tun_protect_input_error
  49 #undef _
  50     IPSEC_TUN_PROTECT_INPUT_N_ERROR,
  51 } ipsec_tun_protect_input_error_t;
  52
  53 typedef enum ipsec_tun_next_t_
  54 {
  55 #define _(v, s) IPSEC_TUN_PROTECT_NEXT_##v,
  56   foreach_ipsec_input_next
  57 #undef _
  58     IPSEC_TUN_PROTECT_NEXT_DECRYPT,
  59   IPSEC_TUN_PROTECT_N_NEXT,
  60 } ipsec_tun_next_t;
  61
  62 typedef struct
  63 {
  64   union
  65   {
  66     ipsec4_tunnel_key_t key4;
  67     ipsec6_tunnel_key_t key6;
  68   };
  69   u8 is_ip6;
  70   u32 seq;
  71   u32 sa_index;
  72 } ipsec_tun_protect_input_trace_t;
  73
  74 static u8 *
  75 format_ipsec_tun_protect_input_trace (u8 * s, va_list * args)
  76 {
  77   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  78   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  79   ipsec_tun_protect_input_trace_t *t =
  80     va_arg (*args, ipsec_tun_protect_input_trace_t *);
  81
  82   if (t->is_ip6)
  83     s = format (s, "IPSec: %U seq %u sa %d",
  84                 format_ipsec6_tunnel_key, &t->key6, t->seq, t->sa_index);
  85   else
  86     s = format (s, "IPSec: %U seq %u sa %d",
  87                 format_ipsec4_tunnel_key, &t->key4, t->seq, t->sa_index);
  88   return s;
  89 }
  90
  91 always_inline u16
  92 ipsec_ip4_if_no_tunnel (vlib_node_runtime_t * node,
  93                         vlib_buffer_t * b,
  94                         const esp_header_t * esp, const ip4_header_t * ip4)
  95 {
  96   if (PREDICT_FALSE (0 == esp->spi))
  97     {
  98       b->error = node->errors[IPSEC_TUN_PROTECT_INPUT_ERROR_SPI_0];
  99       b->punt_reason = ipsec_punt_reason[(ip4->protocol == IP_PROTOCOL_UDP ?
 100                                           IPSEC_PUNT_IP4_SPI_UDP_0 :
 101                                           IPSEC_PUNT_IP4_NO_SUCH_TUNNEL)];
 102     }
 103   else
 104     {
 105       b->error = node->errors[IPSEC_TUN_PROTECT_INPUT_ERROR_NO_TUNNEL];
 106       b->punt_reason = ipsec_punt_reason[IPSEC_PUNT_IP4_NO_SUCH_TUNNEL];
 107     }
 108   return IPSEC_INPUT_NEXT_PUNT;
 109 }
 110
 111 always_inline u16
 112 ipsec_ip6_if_no_tunnel (vlib_node_runtime_t * node,
 113                         vlib_buffer_t * b, const esp_header_t * esp)
 114 {
 115   b->error = node->errors[IPSEC_TUN_PROTECT_INPUT_ERROR_NO_TUNNEL];
 116   b->punt_reason = ipsec_punt_reason[IPSEC_PUNT_IP6_NO_SUCH_TUNNEL];
 117
 118   return (IPSEC_INPUT_NEXT_PUNT);
 119 }
 120
 121 always_inline uword
 122 ipsec_tun_protect_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 123                                 vlib_frame_t * from_frame, int is_ip6)
 124 {
 125   ipsec_main_t *im = &ipsec_main;
 126   vnet_main_t *vnm = im->vnet_main;
 127   vnet_interface_main_t *vim = &vnm->interface_main;
 128
 129   int is_trace = node->flags & VLIB_NODE_FLAG_TRACE;
 130   u32 thread_index = vm->thread_index;
 131
 132   u32 n_left_from, *from;
 133   u16 nexts[VLIB_FRAME_SIZE], *next;
 134   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
 135
 136   from = vlib_frame_vector_args (from_frame);
 137   n_left_from = from_frame->n_vectors;
 138
 139   vlib_get_buffers (vm, from, bufs, n_left_from);
 140   b = bufs;
 141   next = nexts;
 142
 143   clib_memset_u16 (nexts, im->esp4_decrypt_next_index, n_left_from);
 144
 145   u64 n_bytes = 0, n_packets = 0;
 146   u32 n_disabled = 0, n_no_tunnel = 0;
 147
 148   u32 last_sw_if_index = ~0;
 149   ipsec_tun_lkup_result_t last_result = {
 150     .tun_index = ~0
 151   };
 152   ipsec4_tunnel_key_t last_key4;
 153   ipsec6_tunnel_key_t last_key6;
 154
 155   vlib_combined_counter_main_t *rx_counter;
 156   vlib_combined_counter_main_t *drop_counter;
 157   ipsec_tun_protect_t *itp0;
 158
 159   if (is_ip6)
 160     clib_memset (&last_key6, 0xff, sizeof (last_key6));
 161   else
 162     last_key4.as_u64 = ~0;
 163
 164   rx_counter = vim->combined_sw_if_counters + VNET_INTERFACE_COUNTER_RX;
 165   drop_counter = vim->combined_sw_if_counters + VNET_INTERFACE_COUNTER_DROP;
 166
 167   while (n_left_from > 0)
 168     {
 169       u32 sw_if_index0, len0, hdr_sz0;
 170       ipsec_tun_lkup_result_t itr0;
 171       ipsec4_tunnel_key_t key40;
 172       ipsec6_tunnel_key_t key60;
 173       ip4_header_t *ip40;
 174       ip6_header_t *ip60;
 175       esp_header_t *esp0;
 176       u16 buf_rewind0;
 177
 178       ip40 =
 179         (ip4_header_t *) (b[0]->data + vnet_buffer (b[0])->l3_hdr_offset);
 180
 181       if (is_ip6)
 182         {
 183           ip60 = (ip6_header_t *) ip40;
 184           esp0 = (esp_header_t *) (ip60 + 1);
 185           hdr_sz0 = sizeof (ip6_header_t);
 186         }
 187       else
 188         {
 189           /* NAT UDP port 4500 case, don't advance any more */
 190           if (ip40->protocol == IP_PROTOCOL_UDP)
 191             {
 192               esp0 =
 193                 (esp_header_t *) ((u8 *) ip40 + ip4_header_bytes (ip40) +
 194                                   sizeof (udp_header_t));
 195               hdr_sz0 = 0;
 196               buf_rewind0 = ip4_header_bytes (ip40) + sizeof (udp_header_t);
 197             }
 198           else
 199             {
 200               esp0 = (esp_header_t *) ((u8 *) ip40 + ip4_header_bytes (ip40));
 201               buf_rewind0 = hdr_sz0 = ip4_header_bytes (ip40);
 202             }
 203         }
 204
 205       /* stats for the tunnel include all the data after the IP header
 206          just like a norml IP-IP tunnel */
 207       vlib_buffer_advance (b[0], hdr_sz0);
 208       len0 = vlib_buffer_length_in_chain (vm, b[0]);
 209
 210       if (len0 < sizeof (esp_header_t))
 211         {
 212           if (esp0->spi_bytes[0] == 0xff)
 213             b[0]->error =
 214               node->errors[IPSEC_TUN_PROTECT_INPUT_ERROR_NAT_KEEPALIVE];
 215           else
 216             b[0]->error =
 217               node->errors[IPSEC_TUN_PROTECT_INPUT_ERROR_TOO_SHORT];
 218
 219           next[0] = IPSEC_INPUT_NEXT_DROP;
 220           goto trace00;
 221         }
 222
 223       if (is_ip6)
 224         {
 225           key60.remote_ip = ip60->src_address;
 226           key60.spi = esp0->spi;
 227
 228           if (memcmp (&key60, &last_key6, sizeof (last_key6)) == 0)
 229             {
 230               itr0 = last_result;
 231             }
 232           else
 233             {
 234               uword *p = hash_get_mem (im->tun6_protect_by_key, &key60);
 235               if (p)
 236                 {
 237                   itr0.as_u64 = p[0];
 238                   last_result = itr0;
 239                   clib_memcpy_fast (&last_key6, &key60, sizeof (key60));
 240                 }
 241               else
 242                 {
 243                   next[0] = ipsec_ip6_if_no_tunnel (node, b[0], esp0);
 244                   n_no_tunnel++;
 245                   goto trace00;
 246                 }
 247             }
 248         }
 249       else
 250         {
 251           key40.remote_ip = ip40->src_address;
 252           key40.spi = esp0->spi;
 253
 254           if (key40.as_u64 == last_key4.as_u64)
 255             {
 256               itr0 = last_result;
 257             }
 258           else
 259             {
 260               uword *p = hash_get (im->tun4_protect_by_key, key40.as_u64);
 261               if (p)
 262                 {
 263                   itr0.as_u64 = p[0];
 264                   last_result = itr0;
 265                   last_key4.as_u64 = key40.as_u64;
 266                 }
 267               else
 268                 {
 269                   next[0] = ipsec_ip4_if_no_tunnel (node, b[0], esp0, ip40);
 270                   vlib_buffer_advance (b[0], -buf_rewind0);
 271                   n_no_tunnel++;
 272                   goto trace00;
 273                 }
 274             }
 275         }
 276
 277       itp0 = pool_elt_at_index (ipsec_protect_pool, itr0.tun_index);
 278       vnet_buffer (b[0])->ipsec.sad_index = itr0.sa_index;
 279       vnet_buffer (b[0])->ipsec.protect_index = itr0.tun_index;
 280
 281       sw_if_index0 = itp0->itp_sw_if_index;
 282       vnet_buffer (b[0])->sw_if_index[VLIB_RX] = sw_if_index0;
 283
 284       if (PREDICT_FALSE (!vnet_sw_interface_is_admin_up (vnm, sw_if_index0)))
 285         {
 286           vlib_increment_combined_counter
 287             (drop_counter, thread_index, sw_if_index0, 1, len0);
 288           n_disabled++;
 289           b[0]->error = node->errors[IPSEC_TUN_PROTECT_INPUT_ERROR_DISABLED];
 290           next[0] = IPSEC_INPUT_NEXT_DROP;
 291           goto trace00;
 292         }
 293       else
 294         {
 295           if (PREDICT_TRUE (sw_if_index0 == last_sw_if_index))
 296             {
 297               n_packets++;
 298               n_bytes += len0;
 299             }
 300           else
 301             {
 302               if (n_packets && !(itp0->itp_flags & IPSEC_PROTECT_ENCAPED))
 303                 {
 304                   vlib_increment_combined_counter
 305                     (rx_counter, thread_index, last_sw_if_index,
 306                      n_packets, n_bytes);
 307                 }
 308
 309               last_sw_if_index = sw_if_index0;
 310               n_packets = 1;
 311               n_bytes = len0;
 312             }
 313
 314           /*
 315            * compare the packet's outer IP headers to that of the tunnels
 316            */
 317           if (is_ip6)
 318             {
 319               if (PREDICT_FALSE
 320                   (!ip46_address_is_equal_v6
 321                    (&itp0->itp_crypto.dst, &ip60->src_address)
 322                    || !ip46_address_is_equal_v6 (&itp0->itp_crypto.src,
 323                                                  &ip60->dst_address)))
 324                 {
 325                   b[0]->error =
 326                     node->errors
 327                     [IPSEC_TUN_PROTECT_INPUT_ERROR_TUNNEL_MISMATCH];
 328                   next[0] = IPSEC_INPUT_NEXT_DROP;
 329                   goto trace00;
 330                 }
 331             }
 332           else
 333             {
 334               if (PREDICT_FALSE
 335                   (!ip46_address_is_equal_v4
 336                    (&itp0->itp_crypto.dst, &ip40->src_address)
 337                    || !ip46_address_is_equal_v4 (&itp0->itp_crypto.src,
 338                                                  &ip40->dst_address)))
 339                 {
 340                   b[0]->error =
 341                     node->errors
 342                     [IPSEC_TUN_PROTECT_INPUT_ERROR_TUNNEL_MISMATCH];
 343                   next[0] = IPSEC_INPUT_NEXT_DROP;
 344                   goto trace00;
 345                 }
 346             }
 347
 348           /*
 349            * There are two encap possibilities
 350            * 1) the tunnel and ths SA are prodiving encap, i.e. it's
 351            *   MAC | SA-IP | TUN-IP | ESP | PAYLOAD
 352            * implying the SA is in tunnel mode (on a tunnel interface)
 353            * 2) only the tunnel provides encap
 354            *   MAC | TUN-IP | ESP | PAYLOAD
 355            * implying the SA is in transport mode.
 356            *
 357            * For 2) we need only strip the tunnel encap and we're good.
 358            *  since the tunnel and crypto ecnap (int the tun=protect
 359            * object) are the same and we verified above that these match
 360            * for 1) we need to strip the SA-IP outer headers, to
 361            * reveal the tunnel IP and then check that this matches
 362            * the configured tunnel. this we can;t do here since it
 363            * involves a lookup in the per-tunnel-type DB - so ship
 364            * the packet to the tunnel-types provided node to do that
 365            */
 366           next[0] = IPSEC_TUN_PROTECT_NEXT_DECRYPT;
 367         }
 368     trace00:
 369       if (PREDICT_FALSE (is_trace))
 370         {
 371           if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
 372             {
 373               ipsec_tun_protect_input_trace_t *tr =
 374                 vlib_add_trace (vm, node, b[0], sizeof (*tr));
 375               if (is_ip6)
 376                 clib_memcpy (&tr->key6, &key60, sizeof (tr->key6));
 377               else
 378                 clib_memcpy (&tr->key4, &key40, sizeof (tr->key4));
 379               tr->is_ip6 = is_ip6;
 380               tr->seq = (len0 >= sizeof (*esp0) ?
 381                          clib_host_to_net_u32 (esp0->seq) : ~0);
 382               tr->sa_index = vnet_buffer (b[0])->ipsec.sad_index;
 383             }
 384         }
 385
 386       /* next */
 387       b += 1;
 388       next += 1;
 389       n_left_from -= 1;
 390     }
 391
 392   if (n_packets && !(itp0->itp_flags & IPSEC_PROTECT_ENCAPED))
 393     {
 394       vlib_increment_combined_counter (rx_counter,
 395                                        thread_index,
 396                                        last_sw_if_index, n_packets, n_bytes);
 397     }
 398
 399   vlib_node_increment_counter (vm, node->node_index,
 400                                IPSEC_TUN_PROTECT_INPUT_ERROR_RX,
 401                                from_frame->n_vectors - (n_disabled +
 402                                                         n_no_tunnel));
 403
 404   vlib_buffer_enqueue_to_next (vm, node, from, nexts, from_frame->n_vectors);
 405
 406   return from_frame->n_vectors;
 407 }
 408
 409 VLIB_NODE_FN (ipsec4_tun_input_node) (vlib_main_t * vm,
 410                                       vlib_node_runtime_t * node,
 411                                       vlib_frame_t * from_frame)
 412 {
 413   return ipsec_tun_protect_input_inline (vm, node, from_frame,
 414                                          0 /* is_ip6 */ );
 415 }
 416
 417 /* *INDENT-OFF* */
 418 VLIB_REGISTER_NODE (ipsec4_tun_input_node) = {
 419   .name = "ipsec4-tun-input",
 420   .vector_size = sizeof (u32),
 421   .format_trace = format_ipsec_tun_protect_input_trace,
 422   .type = VLIB_NODE_TYPE_INTERNAL,
 423   .n_errors = ARRAY_LEN(ipsec_tun_protect_input_error_strings),
 424   .error_strings = ipsec_tun_protect_input_error_strings,
 425   .n_next_nodes = IPSEC_TUN_PROTECT_N_NEXT,
 426   .next_nodes = {
 427     [IPSEC_TUN_PROTECT_NEXT_DROP] = "ip4-drop",
 428     [IPSEC_TUN_PROTECT_NEXT_PUNT] = "punt-dispatch",
 429     [IPSEC_TUN_PROTECT_NEXT_DECRYPT] = "esp4-decrypt-tun",
 430   }
 431 };
 432 /* *INDENT-ON* */
 433
 434 VLIB_NODE_FN (ipsec6_tun_input_node) (vlib_main_t * vm,
 435                                       vlib_node_runtime_t * node,
 436                                       vlib_frame_t * from_frame)
 437 {
 438   return ipsec_tun_protect_input_inline (vm, node, from_frame,
 439                                          1 /* is_ip6 */ );
 440 }
 441
 442 /* *INDENT-OFF* */
 443 VLIB_REGISTER_NODE (ipsec6_tun_input_node) = {
 444   .name = "ipsec6-tun-input",
 445   .vector_size = sizeof (u32),
 446   .format_trace = format_ipsec_tun_protect_input_trace,
 447   .type = VLIB_NODE_TYPE_INTERNAL,
 448   .n_errors = ARRAY_LEN(ipsec_tun_protect_input_error_strings),
 449   .error_strings = ipsec_tun_protect_input_error_strings,
 450   .n_next_nodes = IPSEC_TUN_PROTECT_N_NEXT,
 451   .next_nodes = {
 452     [IPSEC_TUN_PROTECT_NEXT_DROP] = "ip6-drop",
 453     [IPSEC_TUN_PROTECT_NEXT_PUNT] = "punt-dispatch",
 454     [IPSEC_TUN_PROTECT_NEXT_DECRYPT] = "esp6-decrypt-tun",
 455   }
 456 };
 457 /* *INDENT-ON* */
 458
 459 /*
 460  * fd.io coding-style-patch-verification: ON
 461  *
 462  * Local Variables:
 463  * eval: (c-set-style "gnu")
 464  * End:
 465  */