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