src/vnet/ipsec/ah_encrypt.c

   1 /*
   2  * ah_encrypt.c : IPSec AH encrypt 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/ah.h>
  25
  26 #define foreach_ah_encrypt_next \
  27   _ (DROP, "error-drop")            \
  28   _ (IP4_LOOKUP, "ip4-lookup")      \
  29   _ (IP6_LOOKUP, "ip6-lookup")      \
  30   _ (INTERFACE_OUTPUT, "interface-output")
  31
  32
  33 #define _(v, s) AH_ENCRYPT_NEXT_##v,
  34 typedef enum
  35 {
  36   foreach_ah_encrypt_next
  37 #undef _
  38     AH_ENCRYPT_N_NEXT,
  39 } ah_encrypt_next_t;
  40
  41 #define foreach_ah_encrypt_error                   \
  42  _(RX_PKTS, "AH pkts received")                    \
  43  _(SEQ_CYCLED, "sequence number cycled")
  44
  45
  46 typedef enum
  47 {
  48 #define _(sym,str) AH_ENCRYPT_ERROR_##sym,
  49   foreach_ah_encrypt_error
  50 #undef _
  51     AH_ENCRYPT_N_ERROR,
  52 } ah_encrypt_error_t;
  53
  54 static char *ah_encrypt_error_strings[] = {
  55 #define _(sym,string) string,
  56   foreach_ah_encrypt_error
  57 #undef _
  58 };
  59
  60 typedef struct
  61 {
  62   u32 spi;
  63   u32 seq;
  64   ipsec_integ_alg_t integ_alg;
  65 } ah_encrypt_trace_t;
  66
  67 /* packet trace format function */
  68 static u8 *
  69 format_ah_encrypt_trace (u8 * s, va_list * args)
  70 {
  71   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  72   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  73   ah_encrypt_trace_t *t = va_arg (*args, ah_encrypt_trace_t *);
  74
  75   s = format (s, "ah: spi %u seq %u integrity %U",
  76               t->spi, t->seq, format_ipsec_integ_alg, t->integ_alg);
  77   return s;
  78 }
  79
  80 always_inline uword
  81 ah_encrypt_inline (vlib_main_t * vm,
  82                    vlib_node_runtime_t * node, vlib_frame_t * from_frame,
  83                    int is_ip6)
  84 {
  85   u32 n_left_from, *from, *to_next = 0, next_index;
  86   int icv_size = 0;
  87   from = vlib_frame_vector_args (from_frame);
  88   n_left_from = from_frame->n_vectors;
  89   ipsec_main_t *im = &ipsec_main;
  90   ipsec_proto_main_t *em = &ipsec_proto_main;
  91   next_index = node->cached_next_index;
  92
  93   while (n_left_from > 0)
  94     {
  95       u32 n_left_to_next;
  96
  97       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  98
  99       while (n_left_from > 0 && n_left_to_next > 0)
 100         {
 101           u32 i_bi0, next0;
 102           vlib_buffer_t *i_b0 = 0;
 103           u32 sa_index0;
 104           ipsec_sa_t *sa0;
 105           ip4_and_ah_header_t *ih0, *oh0 = 0;
 106           ip6_and_ah_header_t *ih6_0, *oh6_0 = 0;
 107           u8 ip_hdr_size;
 108           u8 next_hdr_type;
 109           u8 tos = 0;
 110           u8 ttl = 0;
 111           u8 hop_limit = 0;
 112           u32 ip_version_traffic_class_and_flow_label = 0;
 113
 114           i_bi0 = from[0];
 115           from += 1;
 116           n_left_from -= 1;
 117           n_left_to_next -= 1;
 118           next0 = AH_ENCRYPT_NEXT_DROP;
 119
 120           i_b0 = vlib_get_buffer (vm, i_bi0);
 121           to_next[0] = i_bi0;
 122           to_next += 1;
 123           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 124           sa0 = pool_elt_at_index (im->sad, sa_index0);
 125
 126           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 127             {
 128               clib_warning ("sequence number counter has cycled SPI %u",
 129                             sa0->spi);
 130               if (is_ip6)
 131                 vlib_node_increment_counter (vm, ah6_encrypt_node.index,
 132                                              AH_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 133               else
 134                 vlib_node_increment_counter (vm, ah4_encrypt_node.index,
 135                                              AH_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 136               //TODO need to confirm if below is needed
 137               to_next[0] = i_bi0;
 138               to_next += 1;
 139               goto trace;
 140             }
 141
 142
 143           sa0->total_data_size += i_b0->current_length;
 144
 145           ssize_t adv;
 146           ih0 = vlib_buffer_get_current (i_b0);
 147           ttl = ih0->ip4.ttl;
 148           tos = ih0->ip4.tos;
 149
 150           if (PREDICT_TRUE (sa0->is_tunnel))
 151             {
 152               if (is_ip6)
 153                 adv = -sizeof (ip6_and_ah_header_t);
 154               else
 155                 adv = -sizeof (ip4_and_ah_header_t);
 156             }
 157           else
 158             {
 159               adv = -sizeof (ah_header_t);
 160             }
 161
 162           icv_size =
 163             em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
 164           const u8 padding_len = ah_calc_icv_padding_len (icv_size, is_ip6);
 165           adv -= padding_len;
 166           /* transport mode save the eth header before it is overwritten */
 167           if (PREDICT_FALSE (!sa0->is_tunnel))
 168             {
 169               ethernet_header_t *ieh0 = (ethernet_header_t *)
 170                 ((u8 *) vlib_buffer_get_current (i_b0) -
 171                  sizeof (ethernet_header_t));
 172               ethernet_header_t *oeh0 =
 173                 (ethernet_header_t *) ((u8 *) ieh0 + (adv - icv_size));
 174               clib_memcpy (oeh0, ieh0, sizeof (ethernet_header_t));
 175             }
 176
 177           vlib_buffer_advance (i_b0, adv - icv_size);
 178
 179           if (is_ip6)
 180             {
 181               ih6_0 = (ip6_and_ah_header_t *) ih0;
 182               ip_hdr_size = sizeof (ip6_header_t);
 183               oh6_0 = vlib_buffer_get_current (i_b0);
 184
 185               hop_limit = ih6_0->ip6.hop_limit;
 186               ip_version_traffic_class_and_flow_label =
 187                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 188               if (PREDICT_TRUE (sa0->is_tunnel))
 189                 {
 190                   next_hdr_type = IP_PROTOCOL_IPV6;
 191                 }
 192               else
 193                 {
 194                   next_hdr_type = ih6_0->ip6.protocol;
 195                   memmove (oh6_0, ih6_0, sizeof (ip6_header_t));
 196                 }
 197
 198               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_AH;
 199               oh6_0->ip6.hop_limit = 0;
 200               oh6_0->ip6.ip_version_traffic_class_and_flow_label = 0x60;
 201               oh6_0->ah.reserved = 0;
 202               oh6_0->ah.nexthdr = next_hdr_type;
 203               oh6_0->ah.spi = clib_net_to_host_u32 (sa0->spi);
 204               oh6_0->ah.seq_no = clib_net_to_host_u32 (sa0->seq);
 205               oh6_0->ip6.payload_length =
 206                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, i_b0) -
 207                                       sizeof (ip6_header_t));
 208               oh6_0->ah.hdrlen =
 209                 (sizeof (ah_header_t) + icv_size + padding_len) / 4 - 2;
 210             }
 211           else
 212             {
 213               ip_hdr_size = sizeof (ip4_header_t);
 214               oh0 = vlib_buffer_get_current (i_b0);
 215               clib_memset (oh0, 0, sizeof (ip4_and_ah_header_t));
 216
 217               if (PREDICT_TRUE (sa0->is_tunnel))
 218                 {
 219                   next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 220                 }
 221               else
 222                 {
 223                   next_hdr_type = ih0->ip4.protocol;
 224                   memmove (oh0, ih0, sizeof (ip4_header_t));
 225                 }
 226
 227               oh0->ip4.length =
 228                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, i_b0));
 229               oh0->ip4.ip_version_and_header_length = 0x45;
 230               oh0->ip4.fragment_id = 0;
 231               oh0->ip4.flags_and_fragment_offset = 0;
 232               oh0->ip4.ttl = 0;
 233               oh0->ip4.tos = 0;
 234               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_AH;
 235               oh0->ah.spi = clib_net_to_host_u32 (sa0->spi);
 236               oh0->ah.seq_no = clib_net_to_host_u32 (sa0->seq);
 237               oh0->ip4.checksum = 0;
 238               oh0->ah.nexthdr = next_hdr_type;
 239               oh0->ah.hdrlen =
 240                 (sizeof (ah_header_t) + icv_size + padding_len) / 4 - 2;
 241             }
 242
 243
 244           if (PREDICT_TRUE (!is_ip6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 245             {
 246               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 247               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 248
 249               next0 = AH_ENCRYPT_NEXT_IP4_LOOKUP;
 250               vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 251             }
 252           else if (is_ip6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 253             {
 254               oh6_0->ip6.src_address.as_u64[0] =
 255                 sa0->tunnel_src_addr.ip6.as_u64[0];
 256               oh6_0->ip6.src_address.as_u64[1] =
 257                 sa0->tunnel_src_addr.ip6.as_u64[1];
 258               oh6_0->ip6.dst_address.as_u64[0] =
 259                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 260               oh6_0->ip6.dst_address.as_u64[1] =
 261                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 262
 263               next0 = AH_ENCRYPT_NEXT_IP6_LOOKUP;
 264               vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 265             }
 266
 267           u8 sig[64];
 268           clib_memset (sig, 0, sizeof (sig));
 269           u8 *digest =
 270             vlib_buffer_get_current (i_b0) + ip_hdr_size +
 271             sizeof (ah_header_t);
 272           clib_memset (digest, 0, icv_size);
 273
 274           unsigned size = hmac_calc (sa0->integ_alg, sa0->integ_key,
 275                                      sa0->integ_key_len,
 276                                      vlib_buffer_get_current (i_b0),
 277                                      i_b0->current_length, sig, sa0->use_esn,
 278                                      sa0->seq_hi);
 279
 280           memcpy (digest, sig, size);
 281           if (is_ip6)
 282             {
 283               oh6_0->ip6.hop_limit = hop_limit;
 284               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 285                 ip_version_traffic_class_and_flow_label;
 286             }
 287           else
 288             {
 289               oh0->ip4.ttl = ttl;
 290               oh0->ip4.tos = tos;
 291               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 292             }
 293
 294           if (!sa0->is_tunnel)
 295             {
 296               next0 = AH_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 297               vlib_buffer_advance (i_b0, -sizeof (ethernet_header_t));
 298             }
 299
 300         trace:
 301           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 302             {
 303               i_b0->flags |= VLIB_BUFFER_IS_TRACED;
 304               ah_encrypt_trace_t *tr =
 305                 vlib_add_trace (vm, node, i_b0, sizeof (*tr));
 306               tr->spi = sa0->spi;
 307               tr->seq = sa0->seq - 1;
 308               tr->integ_alg = sa0->integ_alg;
 309             }
 310
 311           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 312                                            to_next, n_left_to_next, i_bi0,
 313                                            next0);
 314         }
 315       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 316     }
 317   if (is_ip6)
 318     vlib_node_increment_counter (vm, ah6_encrypt_node.index,
 319                                  AH_ENCRYPT_ERROR_RX_PKTS,
 320                                  from_frame->n_vectors);
 321   else
 322     vlib_node_increment_counter (vm, ah4_encrypt_node.index,
 323                                  AH_ENCRYPT_ERROR_RX_PKTS,
 324                                  from_frame->n_vectors);
 325
 326   return from_frame->n_vectors;
 327 }
 328
 329 static uword
 330 ah4_encrypt_node_fn (vlib_main_t * vm,
 331                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 332 {
 333   return ah_encrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 334 }
 335
 336 /* *INDENT-OFF* */
 337 VLIB_REGISTER_NODE (ah4_encrypt_node) = {
 338   .function = ah4_encrypt_node_fn,
 339   .name = "ah4-encrypt",
 340   .vector_size = sizeof (u32),
 341   .format_trace = format_ah_encrypt_trace,
 342   .type = VLIB_NODE_TYPE_INTERNAL,
 343
 344   .n_errors = ARRAY_LEN(ah_encrypt_error_strings),
 345   .error_strings = ah_encrypt_error_strings,
 346
 347   .n_next_nodes = AH_ENCRYPT_N_NEXT,
 348   .next_nodes = {
 349 #define _(s,n) [AH_ENCRYPT_NEXT_##s] = n,
 350     foreach_ah_encrypt_next
 351 #undef _
 352   },
 353 };
 354 /* *INDENT-ON* */
 355
 356 VLIB_NODE_FUNCTION_MULTIARCH (ah4_encrypt_node, ah4_encrypt_node_fn);
 357
 358 static uword
 359 ah6_encrypt_node_fn (vlib_main_t * vm,
 360                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 361 {
 362   return ah_encrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 363 }
 364
 365 /* *INDENT-OFF* */
 366 VLIB_REGISTER_NODE (ah6_encrypt_node) = {
 367   .function = ah6_encrypt_node_fn,
 368   .name = "ah6-encrypt",
 369   .vector_size = sizeof (u32),
 370   .format_trace = format_ah_encrypt_trace,
 371   .type = VLIB_NODE_TYPE_INTERNAL,
 372
 373   .n_errors = ARRAY_LEN(ah_encrypt_error_strings),
 374   .error_strings = ah_encrypt_error_strings,
 375
 376   .n_next_nodes = AH_ENCRYPT_N_NEXT,
 377   .next_nodes = {
 378 #define _(s,n) [AH_ENCRYPT_NEXT_##s] = n,
 379     foreach_ah_encrypt_next
 380 #undef _
 381   },
 382 };
 383 /* *INDENT-ON* */
 384
 385 VLIB_NODE_FUNCTION_MULTIARCH (ah6_encrypt_node, ah6_encrypt_node_fn);
 386 /*
 387  * fd.io coding-style-patch-verification: ON
 388  *
 389  * Local Variables:
 390  * eval: (c-set-style "gnu")
 391  * End:
 392  */