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   index_t sai;
 195
 196   ipsec_tun_protect_feature_set (itp, 0);
 197
 198   /* *INDENT-OFF* */
 199   FOR_EACH_IPSEC_PROTECT_INPUT_SA(itp, sa,
 200   ({
 201     ipsec_sa_unset_IS_PROTECT (sa);
 202   }));
 203
 204   ipsec_tun_protect_db_remove (im, itp);
 205
 206   ipsec_sa_unlock(itp->itp_out_sa);
 207
 208   FOR_EACH_IPSEC_PROTECT_INPUT_SAI(itp, sai,
 209   ({
 210     ipsec_sa_unlock(sai);
 211   }));
 212   /* *INDENT-ON* */
 213 }
 214
 215 index_t
 216 ipsec_tun_protect_find (u32 sw_if_index)
 217 {
 218   if (vec_len (ipsec_protect_db.tunnels) < sw_if_index)
 219     return (INDEX_INVALID);
 220
 221   return (ipsec_protect_db.tunnels[sw_if_index]);
 222 }
 223
 224 int
 225 ipsec_tun_protect_update (u32 sw_if_index, u32 sa_out, u32 * sas_in)
 226 {
 227   u32 itpi, ii;
 228   ipsec_tun_protect_t *itp;
 229   ipsec_main_t *im;
 230   int rv;
 231
 232   rv = 0;
 233   im = &ipsec_main;
 234   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 235                            INDEX_INVALID);
 236   itpi = ipsec_protect_db.tunnels[sw_if_index];
 237
 238   vec_foreach_index (ii, sas_in)
 239   {
 240     sas_in[ii] = ipsec_sa_find_and_lock (sas_in[ii]);
 241     if (~0 == sas_in[ii])
 242       {
 243         rv = VNET_API_ERROR_INVALID_VALUE;
 244         goto out;
 245       }
 246   }
 247
 248   sa_out = ipsec_sa_find_and_lock (sa_out);
 249
 250   if (~0 == sa_out)
 251     {
 252       rv = VNET_API_ERROR_INVALID_VALUE;
 253       goto out;
 254     }
 255
 256   if (INDEX_INVALID == itpi)
 257     {
 258       vnet_device_class_t *dev_class;
 259       vnet_hw_interface_t *hi;
 260       vnet_main_t *vnm;
 261       u8 is_l2;
 262
 263       vnm = vnet_get_main ();
 264       hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
 265       dev_class = vnet_get_device_class (vnm, hi->dev_class_index);
 266
 267       if (NULL == dev_class->ip_tun_desc)
 268         {
 269           rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;
 270           goto out;
 271         }
 272
 273       pool_get_zero (ipsec_protect_pool, itp);
 274
 275       itp->itp_sw_if_index = sw_if_index;
 276       ipsec_protect_db.tunnels[sw_if_index] = itp - ipsec_protect_pool;
 277       ipsec_protect_db.count++;
 278
 279       itp->itp_n_sa_in = vec_len (sas_in);
 280       for (ii = 0; ii < itp->itp_n_sa_in; ii++)
 281         itp->itp_in_sas[ii] = sas_in[ii];
 282       itp->itp_out_sa = sa_out;
 283
 284       rv = dev_class->ip_tun_desc (sw_if_index,
 285                                    &itp->itp_tun.src,
 286                                    &itp->itp_tun.dst, &is_l2);
 287
 288       if (rv)
 289         goto out;
 290
 291       if (is_l2)
 292         itp->itp_flags |= IPSEC_PROTECT_L2;
 293
 294       /*
 295        * add to the tunnel DB for ingress
 296        *  - if the SA is in trasnport mode, then the packates will arrivw
 297        *    with the IP src,dst of the protected tunnel, in which case we can
 298        *    simply strip the IP header and hand the payload to the protocol
 299        *    appropriate input handler
 300        *  - if the SA is in tunnel mode then there are two IP headers present
 301        *    one for the crytpo tunnel endpoints (described in the SA) and one
 302        *    for the tunnel endpoints. The outer IP headers in the srriving
 303        *    packets will have the crypto endpoints. So the DB needs to contain
 304        *    the crpto endpoint. Once the crypto header is stripped, revealing,
 305        *    the tunnel-IP we have 2 choices:
 306        *     1) do a tunnel lookup based on the revealed header
 307        *     2) skip the tunnel lookup and assume that the packet matches the
 308        *        one that is protected here.
 309        *    If we did 1) then we would allow our peer to use the SA for tunnel
 310        *    X to inject traffic onto tunnel Y, this is not good. If we do 2)
 311        *    then we don't verify that the peer is indeed using SA for tunnel
 312        *    X and addressing tunnel X. So we take a compromise, once the SA
 313        *    matches to tunnel X we veriy that the inner IP matches the value
 314        *    of the tunnel we are protecting, else it's dropped.
 315        */
 316       ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 317
 318       if (1 == hash_elts (im->tun4_protect_by_key))
 319         ip4_register_protocol (IP_PROTOCOL_IPSEC_ESP,
 320                                ipsec4_tun_input_node.index);
 321       if (1 == hash_elts (im->tun6_protect_by_key))
 322         ip6_register_protocol (IP_PROTOCOL_IPSEC_ESP,
 323                                ipsec6_tun_input_node.index);
 324     }
 325   else
 326     {
 327       /* updating SAs only */
 328       itp = pool_elt_at_index (ipsec_protect_pool, itpi);
 329
 330       ipsec_tun_protect_unconfig (im, itp);
 331       ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 332     }
 333
 334   vec_free (sas_in);
 335 out:
 336   return (rv);
 337 }
 338
 339 int
 340 ipsec_tun_protect_del (u32 sw_if_index)
 341 {
 342   ipsec_tun_protect_t *itp;
 343   ipsec_main_t *im;
 344   index_t itpi;
 345
 346   im = &ipsec_main;
 347
 348   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 349                            INDEX_INVALID);
 350   itpi = ipsec_protect_db.tunnels[sw_if_index];
 351
 352   if (INDEX_INVALID == itpi)
 353     return (VNET_API_ERROR_NO_SUCH_ENTRY);
 354
 355   itp = ipsec_tun_protect_get (itpi);
 356   ipsec_tun_protect_unconfig (im, itp);
 357
 358   ipsec_protect_db.tunnels[itp->itp_sw_if_index] = INDEX_INVALID;
 359
 360   pool_put (ipsec_protect_pool, itp);
 361
 362   /* if (0 == hash_elts (im->tun4_protect_by_key)) */
 363   /*   ip4_unregister_protocol (IP_PROTOCOL_IPSEC_ESP); */
 364   /* if (0 == hash_elts (im->tun6_protect_by_key)) */
 365   /*   ip6_unregister_protocol (IP_PROTOCOL_IPSEC_ESP); */
 366
 367   return (0);
 368 }
 369
 370 void
 371 ipsec_tun_protect_walk (ipsec_tun_protect_walk_cb_t fn, void *ctx)
 372 {
 373   index_t itpi;
 374
 375   /* *INDENT-OFF* */
 376   pool_foreach_index(itpi, ipsec_protect_pool,
 377   ({
 378     fn (itpi, ctx);
 379   }));
 380   /* *INDENT-ON* */
 381 }
 382
 383 clib_error_t *
 384 ipsec_tunnel_protect_init (vlib_main_t * vm)
 385 {
 386   ipsec_main_t *im;
 387
 388   im = &ipsec_main;
 389   im->tun6_protect_by_key = hash_create_mem (0,
 390                                              sizeof (ipsec6_tunnel_key_t),
 391                                              sizeof (u64));
 392   im->tun4_protect_by_key = hash_create (0, sizeof (u64));
 393
 394   return 0;
 395 }
 396
 397 VLIB_INIT_FUNCTION (ipsec_tunnel_protect_init);
 398
 399
 400 /*
 401  * fd.io coding-style-patch-verification: ON
 402  *
 403  * Local Variables:
 404  * eval: (c-set-style "gnu")
 405  * End:
 406  */