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   u32 ii;
 152
 153   itp->itp_n_sa_in = vec_len (sas_in);
 154   for (ii = 0; ii < itp->itp_n_sa_in; ii++)
 155     itp->itp_in_sas[ii] = sas_in[ii];
 156   itp->itp_out_sa = sa_out;
 157
 158   /* *INDENT-OFF* */
 159   FOR_EACH_IPSEC_PROTECT_INPUT_SA(itp, sa,
 160   ({
 161     if (ipsec_sa_is_set_IS_TUNNEL (sa))
 162       {
 163         itp->itp_crypto.src = sa->tunnel_dst_addr;
 164         itp->itp_crypto.dst = sa->tunnel_src_addr;
 165         ipsec_sa_set_IS_PROTECT (sa);
 166         itp->itp_flags |= IPSEC_PROTECT_ENCAPED;
 167       }
 168     else
 169       {
 170         itp->itp_crypto.src = itp->itp_tun.src;
 171         itp->itp_crypto.dst = itp->itp_tun.dst;
 172         itp->itp_flags &= ~IPSEC_PROTECT_ENCAPED;
 173       }
 174   }));
 175   /* *INDENT-ON* */
 176
 177   /*
 178    * add to the DB against each SA
 179    */
 180   ipsec_tun_protect_db_add (im, itp);
 181
 182   /*
 183    * enable the encrypt feature for egress.
 184    */
 185   ipsec_tun_protect_feature_set (itp, 1);
 186
 187 }
 188
 189 static void
 190 ipsec_tun_protect_unconfig (ipsec_main_t * im, ipsec_tun_protect_t * itp)
 191 {
 192   ipsec_sa_t *sa;
 193   index_t sai;
 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
 203   ipsec_tun_protect_db_remove (im, itp);
 204
 205   ipsec_sa_unlock(itp->itp_out_sa);
 206
 207   FOR_EACH_IPSEC_PROTECT_INPUT_SAI(itp, sai,
 208   ({
 209     ipsec_sa_unlock(sai);
 210   }));
 211   /* *INDENT-ON* */
 212 }
 213
 214 index_t
 215 ipsec_tun_protect_find (u32 sw_if_index)
 216 {
 217   if (vec_len (ipsec_protect_db.tunnels) < sw_if_index)
 218     return (INDEX_INVALID);
 219
 220   return (ipsec_protect_db.tunnels[sw_if_index]);
 221 }
 222
 223 int
 224 ipsec_tun_protect_update (u32 sw_if_index, u32 sa_out, u32 * sas_in)
 225 {
 226   u32 itpi, ii;
 227   ipsec_tun_protect_t *itp;
 228   ipsec_main_t *im;
 229   int rv;
 230
 231   rv = 0;
 232   im = &ipsec_main;
 233   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 234                            INDEX_INVALID);
 235   itpi = ipsec_protect_db.tunnels[sw_if_index];
 236
 237   vec_foreach_index (ii, sas_in)
 238   {
 239     sas_in[ii] = ipsec_sa_find_and_lock (sas_in[ii]);
 240     if (~0 == sas_in[ii])
 241       {
 242         rv = VNET_API_ERROR_INVALID_VALUE;
 243         goto out;
 244       }
 245   }
 246
 247   sa_out = ipsec_sa_find_and_lock (sa_out);
 248
 249   if (~0 == sa_out)
 250     {
 251       rv = VNET_API_ERROR_INVALID_VALUE;
 252       goto out;
 253     }
 254
 255   if (INDEX_INVALID == itpi)
 256     {
 257       vnet_device_class_t *dev_class;
 258       vnet_hw_interface_t *hi;
 259       vnet_main_t *vnm;
 260       u8 is_l2;
 261
 262       vnm = vnet_get_main ();
 263       hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
 264       dev_class = vnet_get_device_class (vnm, hi->dev_class_index);
 265
 266       if (NULL == dev_class->ip_tun_desc)
 267         {
 268           rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;
 269           goto out;
 270         }
 271
 272       pool_get_zero (ipsec_protect_pool, itp);
 273
 274       itp->itp_sw_if_index = sw_if_index;
 275       ipsec_protect_db.tunnels[sw_if_index] = itp - ipsec_protect_pool;
 276       ipsec_protect_db.count++;
 277
 278       itp->itp_n_sa_in = vec_len (sas_in);
 279       for (ii = 0; ii < itp->itp_n_sa_in; ii++)
 280         itp->itp_in_sas[ii] = sas_in[ii];
 281       itp->itp_out_sa = sa_out;
 282
 283       rv = dev_class->ip_tun_desc (sw_if_index,
 284                                    &itp->itp_tun.src,
 285                                    &itp->itp_tun.dst, &is_l2);
 286
 287       if (rv)
 288         goto out;
 289
 290       if (is_l2)
 291         itp->itp_flags |= IPSEC_PROTECT_L2;
 292
 293       /*
 294        * add to the tunnel DB for ingress
 295        *  - if the SA is in trasnport mode, then the packates will arrivw
 296        *    with the IP src,dst of the protected tunnel, in which case we can
 297        *    simply strip the IP header and hand the payload to the protocol
 298        *    appropriate input handler
 299        *  - if the SA is in tunnel mode then there are two IP headers present
 300        *    one for the crytpo tunnel endpoints (described in the SA) and one
 301        *    for the tunnel endpoints. The outer IP headers in the srriving
 302        *    packets will have the crypto endpoints. So the DB needs to contain
 303        *    the crpto endpoint. Once the crypto header is stripped, revealing,
 304        *    the tunnel-IP we have 2 choices:
 305        *     1) do a tunnel lookup based on the revealed header
 306        *     2) skip the tunnel lookup and assume that the packet matches the
 307        *        one that is protected here.
 308        *    If we did 1) then we would allow our peer to use the SA for tunnel
 309        *    X to inject traffic onto tunnel Y, this is not good. If we do 2)
 310        *    then we don't verify that the peer is indeed using SA for tunnel
 311        *    X and addressing tunnel X. So we take a compromise, once the SA
 312        *    matches to tunnel X we veriy that the inner IP matches the value
 313        *    of the tunnel we are protecting, else it's dropped.
 314        */
 315       ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 316
 317       if (1 == hash_elts (im->tun4_protect_by_key))
 318         ip4_register_protocol (IP_PROTOCOL_IPSEC_ESP,
 319                                ipsec4_tun_input_node.index);
 320       if (1 == hash_elts (im->tun6_protect_by_key))
 321         ip6_register_protocol (IP_PROTOCOL_IPSEC_ESP,
 322                                ipsec6_tun_input_node.index);
 323     }
 324   else
 325     {
 326       /* updating SAs only */
 327       itp = pool_elt_at_index (ipsec_protect_pool, itpi);
 328
 329       ipsec_tun_protect_unconfig (im, itp);
 330       ipsec_tun_protect_config (im, itp, sa_out, sas_in);
 331     }
 332
 333   vec_free (sas_in);
 334 out:
 335   return (rv);
 336 }
 337
 338 int
 339 ipsec_tun_protect_del (u32 sw_if_index)
 340 {
 341   ipsec_tun_protect_t *itp;
 342   ipsec_main_t *im;
 343   index_t itpi;
 344
 345   im = &ipsec_main;
 346
 347   vec_validate_init_empty (ipsec_protect_db.tunnels, sw_if_index,
 348                            INDEX_INVALID);
 349   itpi = ipsec_protect_db.tunnels[sw_if_index];
 350
 351   if (INDEX_INVALID == itpi)
 352     return (VNET_API_ERROR_NO_SUCH_ENTRY);
 353
 354   itp = ipsec_tun_protect_get (itpi);
 355   ipsec_tun_protect_unconfig (im, itp);
 356
 357   ipsec_protect_db.tunnels[itp->itp_sw_if_index] = INDEX_INVALID;
 358
 359   pool_put (ipsec_protect_pool, itp);
 360
 361   if (0 == hash_elts (im->tun4_protect_by_key))
 362     ip4_unregister_protocol (IP_PROTOCOL_IPSEC_ESP);
 363   if (0 == hash_elts (im->tun6_protect_by_key))
 364     ip6_unregister_protocol (IP_PROTOCOL_IPSEC_ESP);
 365
 366   return (0);
 367 }
 368
 369 void
 370 ipsec_tun_protect_walk (ipsec_tun_protect_walk_cb_t fn, void *ctx)
 371 {
 372   index_t itpi;
 373
 374   /* *INDENT-OFF* */
 375   pool_foreach_index(itpi, ipsec_protect_pool,
 376   ({
 377     fn (itpi, ctx);
 378   }));
 379   /* *INDENT-ON* */
 380 }
 381
 382 clib_error_t *
 383 ipsec_tunnel_protect_init (vlib_main_t * vm)
 384 {
 385   ipsec_main_t *im;
 386
 387   im = &ipsec_main;
 388   im->tun6_protect_by_key = hash_create_mem (0,
 389                                              sizeof (ipsec6_tunnel_key_t),
 390                                              sizeof (u64));
 391   im->tun4_protect_by_key = hash_create (0, sizeof (u64));
 392
 393   return 0;
 394 }
 395
 396 VLIB_INIT_FUNCTION (ipsec_tunnel_protect_init);
 397
 398
 399 /*
 400  * fd.io coding-style-patch-verification: ON
 401  *
 402  * Local Variables:
 403  * eval: (c-set-style "gnu")
 404  * End:
 405  */