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 is_ip4, is_l2, rv;
  43
  44   is_ip4 = ip46_address_is_ip4 (&itp->itp_tun.src);
  45   is_l2 = itp->itp_flags & IPSEC_PROTECT_L2;
  46
  47   if (is_ip4)
  48     {
  49       if (is_l2)
  50         rv = vnet_feature_enable_disable ("ethernet-output",
  51                                           "esp4-encrypt-tun",
  52                                           itp->itp_sw_if_index, enable,
  53                                           &sai, sizeof (sai));
  54       else
  55         rv = vnet_feature_enable_disable ("ip4-output",
  56                                           "esp4-encrypt-tun",
  57                                           itp->itp_sw_if_index, enable,
  58                                           &sai, sizeof (sai));
  59     }
  60   else
  61     {
  62       if (is_l2)
  63         rv = vnet_feature_enable_disable ("ethernet-output",
  64                                           "esp6-encrypt-tun",
  65                                           itp->itp_sw_if_index, enable,
  66                                           &sai, sizeof (sai));
  67       else
  68         rv = vnet_feature_enable_disable ("ip6-output",
  69                                           "esp6-encrypt-tun",
  70                                           itp->itp_sw_if_index, enable,
  71                                           &sai, sizeof (sai));
  72     }
  73
  74   ASSERT (!rv);
  75   return (rv);
  76 }
  77
  78 static void
  79 ipsec_tun_protect_db_add (ipsec_main_t * im, const ipsec_tun_protect_t * itp)
  80 {
  81   const ipsec_sa_t *sa;
  82   u32 sai;
  83
  84   /* *INDENT-OFF* */
  85   FOR_EACH_IPSEC_PROTECT_INPUT_SAI(itp, sai,
  86   ({
  87       sa = ipsec_sa_get (sai);
  88
  89       ipsec_tun_lkup_result_t res = {
  90         .tun_index = itp - ipsec_protect_pool,
  91         .sa_index = sai,
  92       };
  93
  94       /*
  95        * The key is formed from the tunnel's destination
  96        * as the packet lookup is done from the packet's source
  97        */
  98       if (ip46_address_is_ip4 (&itp->itp_crypto.dst))
  99         {
 100           ipsec4_tunnel_key_t key = {
 101             .remote_ip = itp->itp_crypto.dst.ip4.as_u32,
 102             .spi = clib_host_to_net_u32 (sa->spi),
 103           };
 104           hash_set (im->tun4_protect_by_key, key.as_u64, res.as_u64);
 105         }
 106       else
 107         {
 108           ipsec6_tunnel_key_t key = {
 109             .remote_ip = itp->itp_crypto.dst.ip6,
 110             .spi = clib_host_to_net_u32 (sa->spi),
 111           };
 112           hash_set_mem_alloc (&im->tun6_protect_by_key, &key, res.as_u64);
 113         }
 114   }))
 115   /* *INDENT-ON* */
 116 }
 117
 118 static void
 119 ipsec_tun_protect_db_remove (ipsec_main_t * im,
 120                              const ipsec_tun_protect_t * itp)
 121 {
 122   const ipsec_sa_t *sa;
 123
 124   /* *INDENT-OFF* */
 125   FOR_EACH_IPSEC_PROTECT_INPUT_SA(itp, sa,
 126   ({
 127       if (ip46_address_is_ip4 (&itp->itp_crypto.dst))
 128         {
 129           ipsec4_tunnel_key_t key = {
 130             .remote_ip = itp->itp_crypto.dst.ip4.as_u32,
 131             .spi = clib_host_to_net_u32 (sa->spi),
 132           };
 133           hash_unset (im->tun4_protect_by_key, &key);
 134         }
 135       else
 136         {
 137           ipsec6_tunnel_key_t key = {
 138             .remote_ip = itp->itp_crypto.dst.ip6,
 139             .spi = clib_host_to_net_u32 (sa->spi),
 140           };
 141           hash_unset_mem_free (&im->tun6_protect_by_key, &key);
 142         }
 143   }))
 144   /* *INDENT-ON* */
 145 }
 146
 147 static void
 148 ipsec_tun_protect_config (ipsec_main_t * im,
 149                           ipsec_tun_protect_t * itp, u32 sa_out, u32 * sas_in)
 150 {
 151   ipsec_sa_t *sa;
 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   /* *INDENT-OFF* */
 160   FOR_EACH_IPSEC_PROTECT_INPUT_SA(itp, sa,
 161   ({
 162     if (ipsec_sa_is_set_IS_TUNNEL (sa))
 163       {
 164         itp->itp_crypto.src = sa->tunnel_dst_addr;
 165         itp->itp_crypto.dst = sa->tunnel_src_addr;
 166         ipsec_sa_set_IS_PROTECT (sa);
 167         itp->itp_flags |= IPSEC_PROTECT_ENCAPED;
 168       }
 169     else
 170       {
 171         itp->itp_crypto.src = itp->itp_tun.src;
 172         itp->itp_crypto.dst = itp->itp_tun.dst;
 173         itp->itp_flags &= ~IPSEC_PROTECT_ENCAPED;
 174       }
 175   }));
 176   /* *INDENT-ON* */
 177
 178   /*
 179    * add to the DB against each SA
 180    */
 181   ipsec_tun_protect_db_add (im, itp);
 182
 183   /*
 184    * enable the encrypt feature for egress.
 185    */
 186   ipsec_tun_protect_feature_set (itp, 1);
 187
 188 }
 189
 190 static void
 191 ipsec_tun_protect_unconfig (ipsec_main_t * im, ipsec_tun_protect_t * itp)
 192 {
 193   ipsec_sa_t *sa;
 194
 195   ipsec_tun_protect_feature_set (itp, 0);
 196
 197   /* *INDENT-OFF* */
 198   FOR_EACH_IPSEC_PROTECT_INPUT_SA(itp, sa,
 199   ({
 200     ipsec_sa_unset_IS_PROTECT (sa);
 201   }));
 202   /* *INDENT-ON* */
 203
 204   ipsec_tun_protect_db_remove (im, itp);
 205 }
 206
 207 index_t
 208 ipsec_tun_protect_find (u32 sw_if_index)
 209 {
 210   if (vec_len (ipsec_protect_db.tunnels) < sw_if_index)
 211     return (INDEX_INVALID);
 212
 213   return (ipsec_protect_db.tunnels[sw_if_index]);
 214 }
 215
 216 int
 217 ipsec_tun_protect_update (u32 sw_if_index, u32 sa_out, u32 * sas_in)
 218 {
 219   u32 itpi, ii;
 220   ipsec_tun_protect_t *itp;
 221   ipsec_main_t *im;
 222   int rv;
 223
 224   rv = 0;
 225   im = &ipsec_main;
 226   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 227                            INDEX_INVALID);
 228   itpi = ipsec_protect_db.tunnels[sw_if_index];
 229
 230   vec_foreach_index (ii, sas_in)
 231   {
 232     sas_in[ii] = ipsec_get_sa_index_by_sa_id (sas_in[ii]);
 233     if (~0 == sas_in[ii])
 234       {
 235         rv = VNET_API_ERROR_INVALID_VALUE;
 236         goto out;
 237       }
 238   }
 239
 240   sa_out = ipsec_get_sa_index_by_sa_id (sa_out);
 241
 242   if (~0 == sa_out)
 243     {
 244       rv = VNET_API_ERROR_INVALID_VALUE;
 245       goto out;
 246     }
 247
 248   if (INDEX_INVALID == itpi)
 249     {
 250       vnet_device_class_t *dev_class;
 251       vnet_hw_interface_t *hi;
 252       vnet_main_t *vnm;
 253       u8 is_l2;
 254
 255       vnm = vnet_get_main ();
 256       hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
 257       dev_class = vnet_get_device_class (vnm, hi->dev_class_index);
 258
 259       if (NULL == dev_class->ip_tun_desc)
 260         {
 261           rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;
 262           goto out;
 263         }
 264
 265       pool_get_zero (ipsec_protect_pool, itp);
 266
 267       itp->itp_sw_if_index = sw_if_index;
 268       ipsec_protect_db.tunnels[sw_if_index] = itp - ipsec_protect_pool;
 269       ipsec_protect_db.count++;
 270
 271       itp->itp_n_sa_in = vec_len (sas_in);
 272       for (ii = 0; ii < itp->itp_n_sa_in; ii++)
 273         itp->itp_in_sas[ii] = sas_in[ii];
 274       itp->itp_out_sa = sa_out;
 275
 276       rv = dev_class->ip_tun_desc (sw_if_index,
 277                                    &itp->itp_tun.src,
 278                                    &itp->itp_tun.dst, &is_l2);
 279
 280       if (rv)
 281         goto out;
 282
 283       if (is_l2)
 284         itp->itp_flags |= IPSEC_PROTECT_L2;
 285
 286       /*
 287        * add to the tunnel DB for ingress
 288        *  - if the SA is in trasnport mode, then the packates will arrivw
 289        *    with the IP src,dst of the protected tunnel, in which case we can
 290        *    simply strip the IP header and hand the payload to the protocol
 291        *    appropriate input handler
 292        *  - if the SA is in tunnel mode then there are two IP headers present
 293        *    one for the crytpo tunnel endpoints (described in the SA) and one
 294        *    for the tunnel endpoints. The outer IP headers in the srriving
 295        *    packets will have the crypto endpoints. So the DB needs to contain
 296        *    the crpto endpoint. Once the crypto header is stripped, revealing,
 297        *    the tunnel-IP we have 2 choices:
 298        *     1) do a tunnel lookup based on the revealed header
 299        *     2) skip the tunnel lookup and assume that the packet matches the
 300        *        one that is protected here.
 301        *    If we did 1) then we would allow our peer to use the SA for tunnel
 302        *    X to inject traffic onto tunnel Y, this is not good. If we do 2)
 303        *    then we don't verify that the peer is indeed using SA for tunnel
 304        *    X and addressing tunnel X. So we take a compromise, once the SA
 305        *    matches to tunnel X we veriy that the inner IP matches the value
 306        *    of the tunnel we are protecting, else it's dropped.
 307        */
 308       ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 309
 310       if (1 == hash_elts (im->tun4_protect_by_key))
 311         ip4_register_protocol (IP_PROTOCOL_IPSEC_ESP,
 312                                ipsec4_tun_input_node.index);
 313       if (1 == hash_elts (im->tun6_protect_by_key))
 314         ip6_register_protocol (IP_PROTOCOL_IPSEC_ESP,
 315                                ipsec6_tun_input_node.index);
 316     }
 317   else
 318     {
 319       /* updating SAs only */
 320       itp = pool_elt_at_index (ipsec_protect_pool, itpi);
 321
 322       ipsec_tun_protect_unconfig (im, itp);
 323       ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 324     }
 325
 326   vec_free (sas_in);
 327 out:
 328   return (rv);
 329 }
 330
 331 int
 332 ipsec_tun_protect_del (u32 sw_if_index)
 333 {
 334   ipsec_tun_protect_t *itp;
 335   ipsec_main_t *im;
 336   index_t itpi;
 337
 338   im = &ipsec_main;
 339
 340   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 341                            INDEX_INVALID);
 342   itpi = ipsec_protect_db.tunnels[sw_if_index];
 343
 344   if (INDEX_INVALID == itpi)
 345     return (VNET_API_ERROR_NO_SUCH_ENTRY);
 346
 347   itp = ipsec_tun_protect_get (itpi);
 348   ipsec_tun_protect_unconfig (im, itp);
 349
 350   ipsec_protect_db.tunnels[itp->itp_sw_if_index] = INDEX_INVALID;
 351
 352   pool_put (ipsec_protect_pool, itp);
 353
 354   /* if (0 == hash_elts (im->tun4_protect_by_key)) */
 355   /*   ip4_unregister_protocol (IP_PROTOCOL_IPSEC_ESP); */
 356   /* if (0 == hash_elts (im->tun6_protect_by_key)) */
 357   /*   ip6_unregister_protocol (IP_PROTOCOL_IPSEC_ESP); */
 358
 359   return (0);
 360 }
 361
 362 void
 363 ipsec_tun_protect_walk (ipsec_tun_protect_walk_cb_t fn, void *ctx)
 364 {
 365   index_t itpi;
 366
 367   /* *INDENT-OFF* */
 368   pool_foreach_index(itpi, ipsec_protect_pool,
 369   ({
 370     fn (itpi, ctx);
 371   }));
 372   /* *INDENT-ON* */
 373 }
 374
 375 clib_error_t *
 376 ipsec_tunnel_protect_init (vlib_main_t * vm)
 377 {
 378   ipsec_main_t *im;
 379
 380   im = &ipsec_main;
 381   im->tun6_protect_by_key = hash_create_mem (0,
 382                                              sizeof (ipsec6_tunnel_key_t),
 383                                              sizeof (u64));
 384   im->tun4_protect_by_key = hash_create (0, sizeof (u64));
 385
 386   return 0;
 387 }
 388
 389 VLIB_INIT_FUNCTION (ipsec_tunnel_protect_init);
 390
 391
 392 /*
 393  * fd.io coding-style-patch-verification: ON
 394  *
 395  * Local Variables:
 396  * eval: (c-set-style "gnu")
 397  * End:
 398  */