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               vlib_node_increment_counter (vm, node->node_index,
 129                                            AH_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 130               goto trace;
 131             }
 132
 133
 134           sa0->total_data_size += i_b0->current_length;
 135
 136           ssize_t adv;
 137           ih0 = vlib_buffer_get_current (i_b0);
 138           ttl = ih0->ip4.ttl;
 139           tos = ih0->ip4.tos;
 140
 141           if (PREDICT_TRUE (sa0->is_tunnel))
 142             {
 143               if (is_ip6)
 144                 adv = -sizeof (ip6_and_ah_header_t);
 145               else
 146                 adv = -sizeof (ip4_and_ah_header_t);
 147             }
 148           else
 149             {
 150               adv = -sizeof (ah_header_t);
 151             }
 152
 153           icv_size =
 154             em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
 155           const u8 padding_len = ah_calc_icv_padding_len (icv_size, is_ip6);
 156           adv -= padding_len;
 157           /* transport mode save the eth header before it is overwritten */
 158           if (PREDICT_FALSE (!sa0->is_tunnel))
 159             {
 160               ethernet_header_t *ieh0 = (ethernet_header_t *)
 161                 ((u8 *) vlib_buffer_get_current (i_b0) -
 162                  sizeof (ethernet_header_t));
 163               ethernet_header_t *oeh0 =
 164                 (ethernet_header_t *) ((u8 *) ieh0 + (adv - icv_size));
 165               clib_memcpy_fast (oeh0, ieh0, sizeof (ethernet_header_t));
 166             }
 167
 168           vlib_buffer_advance (i_b0, adv - icv_size);
 169
 170           if (is_ip6)
 171             {
 172               ih6_0 = (ip6_and_ah_header_t *) ih0;
 173               ip_hdr_size = sizeof (ip6_header_t);
 174               oh6_0 = vlib_buffer_get_current (i_b0);
 175
 176               hop_limit = ih6_0->ip6.hop_limit;
 177               ip_version_traffic_class_and_flow_label =
 178                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 179               if (PREDICT_TRUE (sa0->is_tunnel))
 180                 {
 181                   next_hdr_type = IP_PROTOCOL_IPV6;
 182                 }
 183               else
 184                 {
 185                   next_hdr_type = ih6_0->ip6.protocol;
 186                   memmove (oh6_0, ih6_0, sizeof (ip6_header_t));
 187                 }
 188
 189               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_AH;
 190               oh6_0->ip6.hop_limit = 0;
 191               oh6_0->ip6.ip_version_traffic_class_and_flow_label = 0x60;
 192               oh6_0->ah.reserved = 0;
 193               oh6_0->ah.nexthdr = next_hdr_type;
 194               oh6_0->ah.spi = clib_net_to_host_u32 (sa0->spi);
 195               oh6_0->ah.seq_no = clib_net_to_host_u32 (sa0->seq);
 196               oh6_0->ip6.payload_length =
 197                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, i_b0) -
 198                                       sizeof (ip6_header_t));
 199               oh6_0->ah.hdrlen =
 200                 (sizeof (ah_header_t) + icv_size + padding_len) / 4 - 2;
 201             }
 202           else
 203             {
 204               ip_hdr_size = sizeof (ip4_header_t);
 205               oh0 = vlib_buffer_get_current (i_b0);
 206               clib_memset (oh0, 0, sizeof (ip4_and_ah_header_t));
 207
 208               if (PREDICT_TRUE (sa0->is_tunnel))
 209                 {
 210                   next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 211                 }
 212               else
 213                 {
 214                   next_hdr_type = ih0->ip4.protocol;
 215                   memmove (oh0, ih0, sizeof (ip4_header_t));
 216                 }
 217
 218               oh0->ip4.length =
 219                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, i_b0));
 220               oh0->ip4.ip_version_and_header_length = 0x45;
 221               oh0->ip4.fragment_id = 0;
 222               oh0->ip4.flags_and_fragment_offset = 0;
 223               oh0->ip4.ttl = 0;
 224               oh0->ip4.tos = 0;
 225               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_AH;
 226               oh0->ah.spi = clib_net_to_host_u32 (sa0->spi);
 227               oh0->ah.seq_no = clib_net_to_host_u32 (sa0->seq);
 228               oh0->ip4.checksum = 0;
 229               oh0->ah.nexthdr = next_hdr_type;
 230               oh0->ah.hdrlen =
 231                 (sizeof (ah_header_t) + icv_size + padding_len) / 4 - 2;
 232             }
 233
 234
 235           if (PREDICT_TRUE (!is_ip6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 236             {
 237               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 238               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 239
 240               next0 = AH_ENCRYPT_NEXT_IP4_LOOKUP;
 241               vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 242             }
 243           else if (is_ip6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 244             {
 245               oh6_0->ip6.src_address.as_u64[0] =
 246                 sa0->tunnel_src_addr.ip6.as_u64[0];
 247               oh6_0->ip6.src_address.as_u64[1] =
 248                 sa0->tunnel_src_addr.ip6.as_u64[1];
 249               oh6_0->ip6.dst_address.as_u64[0] =
 250                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 251               oh6_0->ip6.dst_address.as_u64[1] =
 252                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 253
 254               next0 = AH_ENCRYPT_NEXT_IP6_LOOKUP;
 255               vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 256             }
 257
 258           u8 sig[64];
 259           clib_memset (sig, 0, sizeof (sig));
 260           u8 *digest =
 261             vlib_buffer_get_current (i_b0) + ip_hdr_size +
 262             sizeof (ah_header_t);
 263           clib_memset (digest, 0, icv_size);
 264
 265           unsigned size = hmac_calc (sa0->integ_alg, sa0->integ_key,
 266                                      sa0->integ_key_len,
 267                                      vlib_buffer_get_current (i_b0),
 268                                      i_b0->current_length, sig, sa0->use_esn,
 269                                      sa0->seq_hi);
 270
 271           memcpy (digest, sig, size);
 272           if (is_ip6)
 273             {
 274               oh6_0->ip6.hop_limit = hop_limit;
 275               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 276                 ip_version_traffic_class_and_flow_label;
 277             }
 278           else
 279             {
 280               oh0->ip4.ttl = ttl;
 281               oh0->ip4.tos = tos;
 282               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 283             }
 284
 285           if (!sa0->is_tunnel)
 286             {
 287               next0 = AH_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 288               vlib_buffer_advance (i_b0, -sizeof (ethernet_header_t));
 289             }
 290
 291         trace:
 292           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 293             {
 294               i_b0->flags |= VLIB_BUFFER_IS_TRACED;
 295               ah_encrypt_trace_t *tr =
 296                 vlib_add_trace (vm, node, i_b0, sizeof (*tr));
 297               tr->spi = sa0->spi;
 298               tr->seq = sa0->seq - 1;
 299               tr->integ_alg = sa0->integ_alg;
 300             }
 301
 302           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 303                                            to_next, n_left_to_next, i_bi0,
 304                                            next0);
 305         }
 306       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 307     }
 308   vlib_node_increment_counter (vm, node->node_index,
 309                                AH_ENCRYPT_ERROR_RX_PKTS,
 310                                from_frame->n_vectors);
 311
 312   return from_frame->n_vectors;
 313 }
 314
 315 VLIB_NODE_FN (ah4_encrypt_node) (vlib_main_t * vm,
 316                                  vlib_node_runtime_t * node,
 317                                  vlib_frame_t * from_frame)
 318 {
 319   return ah_encrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 320 }
 321
 322 /* *INDENT-OFF* */
 323 VLIB_REGISTER_NODE (ah4_encrypt_node) = {
 324   .name = "ah4-encrypt",
 325   .vector_size = sizeof (u32),
 326   .format_trace = format_ah_encrypt_trace,
 327   .type = VLIB_NODE_TYPE_INTERNAL,
 328
 329   .n_errors = ARRAY_LEN(ah_encrypt_error_strings),
 330   .error_strings = ah_encrypt_error_strings,
 331
 332   .n_next_nodes = AH_ENCRYPT_N_NEXT,
 333   .next_nodes = {
 334 #define _(s,n) [AH_ENCRYPT_NEXT_##s] = n,
 335     foreach_ah_encrypt_next
 336 #undef _
 337   },
 338 };
 339 /* *INDENT-ON* */
 340
 341 VLIB_NODE_FN (ah6_encrypt_node) (vlib_main_t * vm,
 342                                  vlib_node_runtime_t * node,
 343                                  vlib_frame_t * from_frame)
 344 {
 345   return ah_encrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 346 }
 347
 348 /* *INDENT-OFF* */
 349 VLIB_REGISTER_NODE (ah6_encrypt_node) = {
 350   .name = "ah6-encrypt",
 351   .vector_size = sizeof (u32),
 352   .format_trace = format_ah_encrypt_trace,
 353   .type = VLIB_NODE_TYPE_INTERNAL,
 354
 355   .n_errors = ARRAY_LEN(ah_encrypt_error_strings),
 356   .error_strings = ah_encrypt_error_strings,
 357
 358   .n_next_nodes = AH_ENCRYPT_N_NEXT,
 359   .next_nodes = {
 360 #define _(s,n) [AH_ENCRYPT_NEXT_##s] = n,
 361     foreach_ah_encrypt_next
 362 #undef _
 363   },
 364 };
 365 /* *INDENT-ON* */
 366
 367 /*
 368  * fd.io coding-style-patch-verification: ON
 369  *
 370  * Local Variables:
 371  * eval: (c-set-style "gnu")
 372  * End:
 373  */