src/vnet/ipsec/ah_decrypt.c

   1 /*
   2  * ah_decrypt.c : IPSec AH decrypt 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_decrypt_next                \
  27 _(DROP, "error-drop")                           \
  28 _(IP4_INPUT, "ip4-input")                       \
  29 _(IP6_INPUT, "ip6-input")                       \
  30 _(IPSEC_GRE_INPUT, "ipsec-gre-input")
  31
  32 #define _(v, s) AH_DECRYPT_NEXT_##v,
  33 typedef enum
  34 {
  35   foreach_ah_decrypt_next
  36 #undef _
  37     AH_DECRYPT_N_NEXT,
  38 } ah_decrypt_next_t;
  39
  40
  41 #define foreach_ah_decrypt_error                   \
  42  _(RX_PKTS, "AH pkts received")                    \
  43  _(DECRYPTION_FAILED, "AH decryption failed")      \
  44  _(INTEG_ERROR, "Integrity check failed")           \
  45  _(REPLAY, "SA replayed packet")                    \
  46  _(NOT_IP, "Not IP packet (dropped)")
  47
  48
  49 typedef enum
  50 {
  51 #define _(sym,str) AH_DECRYPT_ERROR_##sym,
  52   foreach_ah_decrypt_error
  53 #undef _
  54     AH_DECRYPT_N_ERROR,
  55 } ah_decrypt_error_t;
  56
  57 static char *ah_decrypt_error_strings[] = {
  58 #define _(sym,string) string,
  59   foreach_ah_decrypt_error
  60 #undef _
  61 };
  62
  63 typedef struct
  64 {
  65   ipsec_integ_alg_t integ_alg;
  66 } ah_decrypt_trace_t;
  67
  68 /* packet trace format function */
  69 static u8 *
  70 format_ah_decrypt_trace (u8 * s, va_list * args)
  71 {
  72   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  73   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  74   ah_decrypt_trace_t *t = va_arg (*args, ah_decrypt_trace_t *);
  75
  76   s = format (s, "ah: integrity %U", format_ipsec_integ_alg, t->integ_alg);
  77   return s;
  78 }
  79
  80 static uword
  81 ah_decrypt_node_fn (vlib_main_t * vm,
  82                     vlib_node_runtime_t * node, vlib_frame_t * from_frame)
  83 {
  84   u32 n_left_from, *from, next_index, *to_next;
  85   ipsec_main_t *im = &ipsec_main;
  86   ipsec_proto_main_t *em = &ipsec_proto_main;
  87   from = vlib_frame_vector_args (from_frame);
  88   n_left_from = from_frame->n_vectors;
  89   int icv_size = 0;
  90
  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;
 102           u32 next0;
 103           vlib_buffer_t *i_b0;
 104           ah_header_t *ah0;
 105           ipsec_sa_t *sa0;
 106           u32 sa_index0 = ~0;
 107           u32 seq;
 108           ip4_header_t *ih4 = 0, *oh4 = 0;
 109           ip6_header_t *ih6 = 0, *oh6 = 0;
 110           u8 tunnel_mode = 1;
 111           u8 transport_ip6 = 0;
 112           u8 ip_hdr_size = 0;
 113           u8 tos = 0;
 114           u8 ttl = 0;
 115
 116
 117           i_bi0 = from[0];
 118           from += 1;
 119           n_left_from -= 1;
 120           n_left_to_next -= 1;
 121
 122           next0 = AH_DECRYPT_NEXT_DROP;
 123
 124           i_b0 = vlib_get_buffer (vm, i_bi0);
 125           to_next[0] = i_bi0;
 126           to_next += 1;
 127           ih4 = vlib_buffer_get_current (i_b0);
 128           ip_hdr_size = ip4_header_bytes (ih4);
 129           ah0 = (ah_header_t *) ((u8 *) ih4 + ip_hdr_size);
 130
 131           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 132           sa0 = pool_elt_at_index (im->sad, sa_index0);
 133
 134           seq = clib_host_to_net_u32 (ah0->seq_no);
 135           /* anti-replay check */
 136           //TODO UT remaining
 137           if (sa0->use_anti_replay)
 138             {
 139               int rv = 0;
 140
 141               if (PREDICT_TRUE (sa0->use_esn))
 142                 rv = esp_replay_check_esn (sa0, seq);
 143               else
 144                 rv = esp_replay_check (sa0, seq);
 145
 146               if (PREDICT_FALSE (rv))
 147                 {
 148                   clib_warning ("anti-replay SPI %u seq %u", sa0->spi, seq);
 149                   vlib_node_increment_counter (vm, ah_decrypt_node.index,
 150                                                AH_DECRYPT_ERROR_REPLAY, 1);
 151                   to_next[0] = i_bi0;
 152                   to_next += 1;
 153                   goto trace;
 154                 }
 155             }
 156
 157
 158           sa0->total_data_size += i_b0->current_length;
 159           icv_size =
 160             em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
 161           if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 162             {
 163               u8 sig[64];
 164               u8 digest[64];
 165               memset (sig, 0, sizeof (sig));
 166               memset (digest, 0, sizeof (digest));
 167               u8 *icv =
 168                 vlib_buffer_get_current (i_b0) + ip_hdr_size +
 169                 sizeof (ah_header_t);
 170               memcpy (digest, icv, icv_size);
 171               memset (icv, 0, icv_size);
 172
 173               if ((ih4->ip_version_and_header_length & 0xF0) == 0x40)
 174                 {
 175                   tos = ih4->tos;
 176                   ttl = ih4->ttl;
 177                   ih4->tos = 0;
 178                   ih4->ttl = 0;
 179                   ih4->checksum = 0;
 180                   ih4->flags_and_fragment_offset = 0;
 181                 }               //TODO else part for IPv6
 182               hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
 183                          (u8 *) ih4, i_b0->current_length, sig, sa0->use_esn,
 184                          sa0->seq_hi);
 185
 186               if (PREDICT_FALSE (memcmp (digest, sig, icv_size)))
 187                 {
 188                   vlib_node_increment_counter (vm, ah_decrypt_node.index,
 189                                                AH_DECRYPT_ERROR_INTEG_ERROR,
 190                                                1);
 191                   to_next[0] = i_bi0;
 192                   to_next += 1;
 193                   goto trace;
 194                 }
 195
 196               //TODO UT remaining
 197               if (PREDICT_TRUE (sa0->use_anti_replay))
 198                 {
 199                   if (PREDICT_TRUE (sa0->use_esn))
 200                     esp_replay_advance_esn (sa0, seq);
 201                   else
 202                     esp_replay_advance (sa0, seq);
 203                 }
 204
 205             }
 206
 207
 208           vlib_buffer_advance (i_b0,
 209                                ip_hdr_size + sizeof (ah_header_t) + icv_size);
 210           i_b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
 211
 212           /* transport mode */
 213           if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
 214             {
 215               tunnel_mode = 0;
 216
 217               if (PREDICT_TRUE
 218                   ((ih4->ip_version_and_header_length & 0xF0) != 0x40))
 219                 {
 220                   if (PREDICT_TRUE
 221                       ((ih4->ip_version_and_header_length & 0xF0) == 0x60))
 222                     transport_ip6 = 1;
 223                   else
 224                     {
 225                       clib_warning ("next header: 0x%x", ah0->nexthdr);
 226                       vlib_node_increment_counter (vm, ah_decrypt_node.index,
 227                                                    AH_DECRYPT_ERROR_NOT_IP,
 228                                                    1);
 229                       goto trace;
 230                     }
 231                 }
 232             }
 233
 234           if (PREDICT_TRUE (tunnel_mode))
 235             {
 236               if (PREDICT_TRUE (ah0->nexthdr == IP_PROTOCOL_IP_IN_IP))
 237                 next0 = AH_DECRYPT_NEXT_IP4_INPUT;
 238               else if (ah0->nexthdr == IP_PROTOCOL_IPV6)
 239                 next0 = AH_DECRYPT_NEXT_IP6_INPUT;
 240               else
 241                 {
 242                   clib_warning ("next header: 0x%x", ah0->nexthdr);
 243                   vlib_node_increment_counter (vm, ah_decrypt_node.index,
 244                                                AH_DECRYPT_ERROR_DECRYPTION_FAILED,
 245                                                1);
 246                   goto trace;
 247                 }
 248             }
 249           /* transport mode */
 250           else
 251             {
 252               if (PREDICT_FALSE (transport_ip6))
 253                 {
 254                   ih6 =
 255                     (ip6_header_t *) (i_b0->data +
 256                                       sizeof (ethernet_header_t));
 257                   vlib_buffer_advance (i_b0, -sizeof (ip6_header_t));
 258                   oh6 = vlib_buffer_get_current (i_b0);
 259                   memmove (oh6, ih6, sizeof (ip6_header_t));
 260
 261                   next0 = AH_DECRYPT_NEXT_IP6_INPUT;
 262                   oh6->protocol = ah0->nexthdr;
 263                   oh6->payload_length =
 264                     clib_host_to_net_u16 (vlib_buffer_length_in_chain
 265                                           (vm, i_b0) - sizeof (ip6_header_t));
 266                 }
 267               else
 268                 {
 269                   vlib_buffer_advance (i_b0, -sizeof (ip4_header_t));
 270                   oh4 = vlib_buffer_get_current (i_b0);
 271                   memmove (oh4, ih4, sizeof (ip4_header_t));
 272
 273                   next0 = AH_DECRYPT_NEXT_IP4_INPUT;
 274                   oh4->ip_version_and_header_length = 0x45;
 275                   oh4->fragment_id = 0;
 276                   oh4->flags_and_fragment_offset = 0;
 277                   oh4->protocol = ah0->nexthdr;
 278                   oh4->length =
 279                     clib_host_to_net_u16 (vlib_buffer_length_in_chain
 280                                           (vm, i_b0));
 281                   oh4->ttl = ttl;
 282                   oh4->tos = tos;
 283                   oh4->checksum = ip4_header_checksum (oh4);
 284                 }
 285             }
 286
 287           /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 288           if (PREDICT_FALSE
 289               ((vnet_buffer (i_b0)->ipsec.flags) &
 290                IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 291             next0 = AH_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 292
 293
 294           vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 295         trace:
 296           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 297             {
 298               i_b0->flags |= VLIB_BUFFER_IS_TRACED;
 299               ah_decrypt_trace_t *tr =
 300                 vlib_add_trace (vm, node, i_b0, sizeof (*tr));
 301               tr->integ_alg = sa0->integ_alg;
 302             }
 303           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 304                                            n_left_to_next, i_bi0, next0);
 305         }
 306       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 307     }
 308   vlib_node_increment_counter (vm, ah_decrypt_node.index,
 309                                AH_DECRYPT_ERROR_RX_PKTS,
 310                                from_frame->n_vectors);
 311
 312   return from_frame->n_vectors;
 313 }
 314
 315
 316 /* *INDENT-OFF* */
 317 VLIB_REGISTER_NODE (ah_decrypt_node) = {
 318   .function = ah_decrypt_node_fn,
 319   .name = "ah-decrypt",
 320   .vector_size = sizeof (u32),
 321   .format_trace = format_ah_decrypt_trace,
 322   .type = VLIB_NODE_TYPE_INTERNAL,
 323
 324   .n_errors = ARRAY_LEN(ah_decrypt_error_strings),
 325   .error_strings = ah_decrypt_error_strings,
 326
 327   .n_next_nodes = AH_DECRYPT_N_NEXT,
 328   .next_nodes = {
 329 #define _(s,n) [AH_DECRYPT_NEXT_##s] = n,
 330     foreach_ah_decrypt_next
 331 #undef _
 332   },
 333 };
 334 /* *INDENT-ON* */
 335
 336 VLIB_NODE_FUNCTION_MULTIARCH (ah_decrypt_node, ah_decrypt_node_fn)
 337 /*
 338  * fd.io coding-style-patch-verification: ON
 339  *
 340  * Local Variables:
 341  * eval: (c-set-style "gnu")
 342  * End:
 343  */