src/vnet/ipsec/ipsec_tun.c

   1 /*
   2  * ipsec_tun.h : IPSEC tunnel protection
   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/ipsec/ipsec_tun.h>
  19 #include <vnet/ipsec/esp.h>
  20 #include <vnet/udp/udp.h>
  21
  22 /**
  23  * Pool of tunnel protection objects
  24  */
  25 ipsec_tun_protect_t *ipsec_protect_pool;
  26
  27 /**
  28  * DB of protected tunnels
  29  */
  30 typedef struct ipsec_protect_db_t_
  31 {
  32   u32 *tunnels;
  33   u32 count;
  34 } ipsec_protect_db_t;
  35
  36 static ipsec_protect_db_t ipsec_protect_db;
  37
  38 static int
  39 ipsec_tun_protect_feature_set (ipsec_tun_protect_t * itp, u8 enable)
  40 {
  41   u32 sai = itp->itp_out_sa;
  42   int rv;
  43
  44   const char *enc_node = (ip46_address_is_ip4 (&itp->itp_tun.src) ?
  45                           "esp4-encrypt-tun" : "esp6-encrypt-tun");
  46
  47   if (itp->itp_flags & IPSEC_PROTECT_L2)
  48     {
  49       rv = vnet_feature_enable_disable ("ethernet-output",
  50                                         enc_node,
  51                                         itp->itp_sw_if_index, enable,
  52                                         &sai, sizeof (sai));
  53     }
  54   else
  55     {
  56       rv = vnet_feature_enable_disable ("ip4-output",
  57                                         enc_node,
  58                                         itp->itp_sw_if_index, enable,
  59                                         &sai, sizeof (sai));
  60       rv = vnet_feature_enable_disable ("ip6-output",
  61                                         enc_node,
  62                                         itp->itp_sw_if_index, enable,
  63                                         &sai, sizeof (sai));
  64     }
  65   ASSERT (!rv);
  66   return (rv);
  67 }
  68
  69 static void
  70 ipsec_tun_protect_db_add (ipsec_main_t * im, const ipsec_tun_protect_t * itp)
  71 {
  72   const ipsec_sa_t *sa;
  73   u32 sai;
  74
  75   /* *INDENT-OFF* */
  76   FOR_EACH_IPSEC_PROTECT_INPUT_SAI(itp, sai,
  77   ({
  78       sa = ipsec_sa_get (sai);
  79
  80       ipsec_tun_lkup_result_t res = {
  81         .tun_index = itp - ipsec_protect_pool,
  82         .sa_index = sai,
  83       };
  84
  85       /*
  86        * The key is formed from the tunnel's destination
  87        * as the packet lookup is done from the packet's source
  88        */
  89       if (ip46_address_is_ip4 (&itp->itp_crypto.dst))
  90         {
  91           ipsec4_tunnel_key_t key = {
  92             .remote_ip = itp->itp_crypto.dst.ip4,
  93             .spi = clib_host_to_net_u32 (sa->spi),
  94           };
  95           hash_set (im->tun4_protect_by_key, key.as_u64, res.as_u64);
  96           if (1 == hash_elts(im->tun4_protect_by_key))
  97             udp_register_dst_port (vlib_get_main(),
  98                                    UDP_DST_PORT_ipsec,
  99                                    ipsec4_tun_input_node.index, 1);
 100         }
 101       else
 102         {
 103           ipsec6_tunnel_key_t key = {
 104             .remote_ip = itp->itp_crypto.dst.ip6,
 105             .spi = clib_host_to_net_u32 (sa->spi),
 106           };
 107           hash_set_mem_alloc (&im->tun6_protect_by_key, &key, res.as_u64);
 108         }
 109   }))
 110   /* *INDENT-ON* */
 111 }
 112
 113 static void
 114 ipsec_tun_protect_db_remove (ipsec_main_t * im,
 115                              const ipsec_tun_protect_t * itp)
 116 {
 117   const ipsec_sa_t *sa;
 118
 119   /* *INDENT-OFF* */
 120   FOR_EACH_IPSEC_PROTECT_INPUT_SA(itp, sa,
 121   ({
 122       if (ip46_address_is_ip4 (&itp->itp_crypto.dst))
 123         {
 124           ipsec4_tunnel_key_t key = {
 125             .remote_ip = itp->itp_crypto.dst.ip4,
 126             .spi = clib_host_to_net_u32 (sa->spi),
 127           };
 128           hash_unset (im->tun4_protect_by_key, key.as_u64);
 129           if (0 == hash_elts(im->tun4_protect_by_key))
 130             udp_unregister_dst_port (vlib_get_main(),
 131                                      UDP_DST_PORT_ipsec,
 132                                      1);
 133         }
 134       else
 135         {
 136           ipsec6_tunnel_key_t key = {
 137             .remote_ip = itp->itp_crypto.dst.ip6,
 138             .spi = clib_host_to_net_u32 (sa->spi),
 139           };
 140           hash_unset_mem_free (&im->tun6_protect_by_key, &key);
 141         }
 142   }))
 143   /* *INDENT-ON* */
 144 }
 145
 146 static void
 147 ipsec_tun_protect_config (ipsec_main_t * im,
 148                           ipsec_tun_protect_t * itp, u32 sa_out, u32 * sas_in)
 149 {
 150   ipsec_sa_t *sa;
 151   index_t sai;
 152   u32 ii;
 153
 154   itp->itp_n_sa_in = vec_len (sas_in);
 155   for (ii = 0; ii < itp->itp_n_sa_in; ii++)
 156     itp->itp_in_sas[ii] = sas_in[ii];
 157   itp->itp_out_sa = sa_out;
 158
 159   ipsec_sa_lock (itp->itp_out_sa);
 160
 161   /* *INDENT-OFF* */
 162   FOR_EACH_IPSEC_PROTECT_INPUT_SAI(itp, sai,
 163   ({
 164     ipsec_sa_lock(sai);
 165   }));
 166   FOR_EACH_IPSEC_PROTECT_INPUT_SA(itp, sa,
 167   ({
 168     if (ipsec_sa_is_set_IS_TUNNEL (sa))
 169       {
 170         itp->itp_crypto.src = sa->tunnel_dst_addr;
 171         itp->itp_crypto.dst = sa->tunnel_src_addr;
 172         ipsec_sa_set_IS_PROTECT (sa);
 173         itp->itp_flags |= IPSEC_PROTECT_ENCAPED;
 174       }
 175     else
 176       {
 177         itp->itp_crypto.src = itp->itp_tun.src;
 178         itp->itp_crypto.dst = itp->itp_tun.dst;
 179         itp->itp_flags &= ~IPSEC_PROTECT_ENCAPED;
 180       }
 181   }));
 182   /* *INDENT-ON* */
 183
 184   /*
 185    * add to the DB against each SA
 186    */
 187   ipsec_tun_protect_db_add (im, itp);
 188
 189   /*
 190    * enable the encrypt feature for egress.
 191    */
 192   ipsec_tun_protect_feature_set (itp, 1);
 193 }
 194
 195 static void
 196 ipsec_tun_protect_unconfig (ipsec_main_t * im, ipsec_tun_protect_t * itp)
 197 {
 198   ipsec_sa_t *sa;
 199   index_t sai;
 200
 201   ipsec_tun_protect_feature_set (itp, 0);
 202
 203   /* *INDENT-OFF* */
 204   FOR_EACH_IPSEC_PROTECT_INPUT_SA(itp, sa,
 205   ({
 206     ipsec_sa_unset_IS_PROTECT (sa);
 207   }));
 208
 209   ipsec_tun_protect_db_remove (im, itp);
 210
 211   ipsec_sa_unlock(itp->itp_out_sa);
 212
 213   FOR_EACH_IPSEC_PROTECT_INPUT_SAI(itp, sai,
 214   ({
 215     ipsec_sa_unlock(sai);
 216   }));
 217   /* *INDENT-ON* */
 218 }
 219
 220 index_t
 221 ipsec_tun_protect_find (u32 sw_if_index)
 222 {
 223   if (vec_len (ipsec_protect_db.tunnels) < sw_if_index)
 224     return (INDEX_INVALID);
 225
 226   return (ipsec_protect_db.tunnels[sw_if_index]);
 227 }
 228
 229 int
 230 ipsec_tun_protect_update_one (u32 sw_if_index, u32 sa_out, u32 sa_in)
 231 {
 232   u32 *sas_in = NULL;
 233   int rv;
 234
 235   vec_add1 (sas_in, sa_in);
 236   rv = ipsec_tun_protect_update (sw_if_index, sa_out, sas_in);
 237
 238   return (rv);
 239 }
 240
 241 int
 242 ipsec_tun_protect_update_out (u32 sw_if_index, u32 sa_out)
 243 {
 244   u32 itpi, *sas_in, sai, *saip;
 245   ipsec_tun_protect_t *itp;
 246   ipsec_main_t *im;
 247   int rv;
 248
 249   sas_in = NULL;
 250   rv = 0;
 251   im = &ipsec_main;
 252   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 253                            INDEX_INVALID);
 254   itpi = ipsec_protect_db.tunnels[sw_if_index];
 255
 256   if (INDEX_INVALID == itpi)
 257     {
 258       return (VNET_API_ERROR_INVALID_INTERFACE);
 259     }
 260
 261   itp = pool_elt_at_index (ipsec_protect_pool, itpi);
 262
 263   /* *INDENT-0FF* */
 264   FOR_EACH_IPSEC_PROTECT_INPUT_SAI (itp, sai, (
 265                                                 {
 266                                                 ipsec_sa_lock (sai);
 267                                                 vec_add1 (sas_in, sai);
 268                                                 }
 269                                     ));
 270   /* *INDENT-ON* */
 271
 272   sa_out = ipsec_sa_find_and_lock (sa_out);
 273
 274   if (~0 == sa_out)
 275     {
 276       rv = VNET_API_ERROR_INVALID_VALUE;
 277       goto out;
 278     }
 279
 280   ipsec_tun_protect_unconfig (im, itp);
 281   ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 282
 283   ipsec_sa_unlock (sa_out);
 284   vec_foreach (saip, sas_in) ipsec_sa_unlock (*saip);
 285
 286 out:
 287   vec_free (sas_in);
 288   return (rv);
 289 }
 290
 291 int
 292 ipsec_tun_protect_update_in (u32 sw_if_index, u32 sa_in)
 293 {
 294   u32 itpi, *sas_in, sa_out;
 295   ipsec_tun_protect_t *itp;
 296   ipsec_main_t *im;
 297   int rv;
 298
 299   sas_in = NULL;
 300   rv = 0;
 301   im = &ipsec_main;
 302   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 303                            INDEX_INVALID);
 304   itpi = ipsec_protect_db.tunnels[sw_if_index];
 305
 306   if (INDEX_INVALID == itpi)
 307     {
 308       return (VNET_API_ERROR_INVALID_INTERFACE);
 309     }
 310
 311   sa_in = ipsec_sa_find_and_lock (sa_in);
 312
 313   if (~0 == sa_in)
 314     {
 315       rv = VNET_API_ERROR_INVALID_VALUE;
 316       goto out;
 317     }
 318   vec_add1 (sas_in, sa_in);
 319
 320   itp = pool_elt_at_index (ipsec_protect_pool, itpi);
 321   sa_out = itp->itp_out_sa;
 322
 323   ipsec_sa_lock (sa_out);
 324
 325   ipsec_tun_protect_unconfig (im, itp);
 326   ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 327
 328   ipsec_sa_unlock (sa_out);
 329   ipsec_sa_unlock (sa_in);
 330 out:
 331   vec_free (sas_in);
 332   return (rv);
 333 }
 334
 335 int
 336 ipsec_tun_protect_update (u32 sw_if_index, u32 sa_out, u32 * sas_in)
 337 {
 338   ipsec_tun_protect_t *itp;
 339   u32 itpi, ii, *saip;
 340   ipsec_main_t *im;
 341   int rv;
 342
 343   rv = 0;
 344   im = &ipsec_main;
 345   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 346                            INDEX_INVALID);
 347   itpi = ipsec_protect_db.tunnels[sw_if_index];
 348
 349   vec_foreach_index (ii, sas_in)
 350   {
 351     sas_in[ii] = ipsec_sa_find_and_lock (sas_in[ii]);
 352     if (~0 == sas_in[ii])
 353       {
 354         rv = VNET_API_ERROR_INVALID_VALUE;
 355         goto out;
 356       }
 357   }
 358
 359   sa_out = ipsec_sa_find_and_lock (sa_out);
 360
 361   if (~0 == sa_out)
 362     {
 363       rv = VNET_API_ERROR_INVALID_VALUE;
 364       goto out;
 365     }
 366
 367   if (INDEX_INVALID == itpi)
 368     {
 369       vnet_device_class_t *dev_class;
 370       vnet_hw_interface_t *hi;
 371       vnet_main_t *vnm;
 372       u8 is_l2;
 373
 374       vnm = vnet_get_main ();
 375       hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
 376       dev_class = vnet_get_device_class (vnm, hi->dev_class_index);
 377
 378       if (NULL == dev_class->ip_tun_desc)
 379         {
 380           rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;
 381           goto out;
 382         }
 383
 384       pool_get_zero (ipsec_protect_pool, itp);
 385
 386       itp->itp_sw_if_index = sw_if_index;
 387       ipsec_protect_db.tunnels[sw_if_index] = itp - ipsec_protect_pool;
 388       ipsec_protect_db.count++;
 389
 390       itp->itp_n_sa_in = vec_len (sas_in);
 391       for (ii = 0; ii < itp->itp_n_sa_in; ii++)
 392         itp->itp_in_sas[ii] = sas_in[ii];
 393       itp->itp_out_sa = sa_out;
 394
 395       rv = dev_class->ip_tun_desc (sw_if_index,
 396                                    &itp->itp_tun.src,
 397                                    &itp->itp_tun.dst, &is_l2);
 398
 399       if (rv)
 400         goto out;
 401
 402       if (is_l2)
 403         itp->itp_flags |= IPSEC_PROTECT_L2;
 404
 405       /*
 406        * add to the tunnel DB for ingress
 407        *  - if the SA is in trasnport mode, then the packates will arrivw
 408        *    with the IP src,dst of the protected tunnel, in which case we can
 409        *    simply strip the IP header and hand the payload to the protocol
 410        *    appropriate input handler
 411        *  - if the SA is in tunnel mode then there are two IP headers present
 412        *    one for the crytpo tunnel endpoints (described in the SA) and one
 413        *    for the tunnel endpoints. The outer IP headers in the srriving
 414        *    packets will have the crypto endpoints. So the DB needs to contain
 415        *    the crpto endpoint. Once the crypto header is stripped, revealing,
 416        *    the tunnel-IP we have 2 choices:
 417        *     1) do a tunnel lookup based on the revealed header
 418        *     2) skip the tunnel lookup and assume that the packet matches the
 419        *        one that is protected here.
 420        *    If we did 1) then we would allow our peer to use the SA for tunnel
 421        *    X to inject traffic onto tunnel Y, this is not good. If we do 2)
 422        *    then we don't verify that the peer is indeed using SA for tunnel
 423        *    X and addressing tunnel X. So we take a compromise, once the SA
 424        *    matches to tunnel X we veriy that the inner IP matches the value
 425        *    of the tunnel we are protecting, else it's dropped.
 426        */
 427       ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 428
 429       if (1 == hash_elts (im->tun4_protect_by_key))
 430         ip4_register_protocol (IP_PROTOCOL_IPSEC_ESP,
 431                                ipsec4_tun_input_node.index);
 432       if (1 == hash_elts (im->tun6_protect_by_key))
 433         ip6_register_protocol (IP_PROTOCOL_IPSEC_ESP,
 434                                ipsec6_tun_input_node.index);
 435     }
 436   else
 437     {
 438       /* updating SAs only */
 439       itp = pool_elt_at_index (ipsec_protect_pool, itpi);
 440
 441       ipsec_tun_protect_unconfig (im, itp);
 442       ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 443     }
 444
 445   ipsec_sa_unlock (sa_out);
 446   vec_foreach (saip, sas_in) ipsec_sa_unlock (*saip);
 447   vec_free (sas_in);
 448
 449 out:
 450   return (rv);
 451 }
 452
 453 int
 454 ipsec_tun_protect_del (u32 sw_if_index)
 455 {
 456   ipsec_tun_protect_t *itp;
 457   ipsec_main_t *im;
 458   index_t itpi;
 459
 460   im = &ipsec_main;
 461
 462   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 463                            INDEX_INVALID);
 464   itpi = ipsec_protect_db.tunnels[sw_if_index];
 465
 466   if (INDEX_INVALID == itpi)
 467     return (VNET_API_ERROR_NO_SUCH_ENTRY);
 468
 469   itp = ipsec_tun_protect_get (itpi);
 470   ipsec_tun_protect_unconfig (im, itp);
 471
 472   ipsec_protect_db.tunnels[itp->itp_sw_if_index] = INDEX_INVALID;
 473
 474   pool_put (ipsec_protect_pool, itp);
 475
 476   if (0 == hash_elts (im->tun4_protect_by_key))
 477     ip4_unregister_protocol (IP_PROTOCOL_IPSEC_ESP);
 478   if (0 == hash_elts (im->tun6_protect_by_key))
 479     ip6_unregister_protocol (IP_PROTOCOL_IPSEC_ESP);
 480
 481   return (0);
 482 }
 483
 484 void
 485 ipsec_tun_protect_walk (ipsec_tun_protect_walk_cb_t fn, void *ctx)
 486 {
 487   index_t itpi;
 488
 489   /* *INDENT-OFF* */
 490   pool_foreach_index(itpi, ipsec_protect_pool,
 491   ({
 492     fn (itpi, ctx);
 493   }));
 494   /* *INDENT-ON* */
 495 }
 496
 497 clib_error_t *
 498 ipsec_tunnel_protect_init (vlib_main_t * vm)
 499 {
 500   ipsec_main_t *im;
 501
 502   im = &ipsec_main;
 503   im->tun6_protect_by_key = hash_create_mem (0,
 504                                              sizeof (ipsec6_tunnel_key_t),
 505                                              sizeof (u64));
 506   im->tun4_protect_by_key = hash_create (0, sizeof (u64));
 507
 508   return 0;
 509 }
 510
 511 VLIB_INIT_FUNCTION (ipsec_tunnel_protect_init);
 512
 513
 514 /*
 515  * fd.io coding-style-patch-verification: ON
 516  *
 517  * Local Variables:
 518  * eval: (c-set-style "gnu")
 519  * End:
 520  */