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_lo;
  65   u32 seq_hi;
  66   ipsec_integ_alg_t integ_alg;
  67 } ah_encrypt_trace_t;
  68
  69 /* packet trace format function */
  70 static u8 *
  71 format_ah_encrypt_trace (u8 * s, va_list * args)
  72 {
  73   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  74   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  75   ah_encrypt_trace_t *t = va_arg (*args, ah_encrypt_trace_t *);
  76
  77   s = format (s, "ah: sa-index %d spi %u seq %u:%u integrity %U",
  78               t->sa_index, t->spi, t->seq_hi, t->seq_lo,
  79               format_ipsec_integ_alg, t->integ_alg);
  80   return s;
  81 }
  82
  83 always_inline uword
  84 ah_encrypt_inline (vlib_main_t * vm,
  85                    vlib_node_runtime_t * node, vlib_frame_t * from_frame,
  86                    int is_ip6)
  87 {
  88   u32 n_left_from, *from, *to_next = 0, next_index, thread_index;
  89   int icv_size = 0;
  90   from = vlib_frame_vector_args (from_frame);
  91   n_left_from = from_frame->n_vectors;
  92   ipsec_main_t *im = &ipsec_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               i_b0->error = node->errors[AH_ENCRYPT_ERROR_SEQ_CYCLED];
 132               goto trace;
 133             }
 134           vlib_increment_combined_counter
 135             (&ipsec_sa_counters, thread_index, sa_index0,
 136              1, i_b0->current_length);
 137
 138           ssize_t adv;
 139           ih0 = vlib_buffer_get_current (i_b0);
 140           ttl = ih0->ip4.ttl;
 141           tos = ih0->ip4.tos;
 142
 143           if (PREDICT_TRUE (sa0->is_tunnel))
 144             {
 145               if (is_ip6)
 146                 adv = -sizeof (ip6_and_ah_header_t);
 147               else
 148                 adv = -sizeof (ip4_and_ah_header_t);
 149             }
 150           else
 151             {
 152               adv = -sizeof (ah_header_t);
 153             }
 154
 155           icv_size = sa0->integ_trunc_size;
 156           const u8 padding_len = ah_calc_icv_padding_len (icv_size, is_ip6);
 157           adv -= padding_len;
 158           /* transport mode save the eth header before it is overwritten */
 159           if (PREDICT_FALSE (!sa0->is_tunnel))
 160             {
 161               ethernet_header_t *ieh0 = (ethernet_header_t *)
 162                 ((u8 *) vlib_buffer_get_current (i_b0) -
 163                  sizeof (ethernet_header_t));
 164               ethernet_header_t *oeh0 =
 165                 (ethernet_header_t *) ((u8 *) ieh0 + (adv - icv_size));
 166               clib_memcpy_fast (oeh0, ieh0, sizeof (ethernet_header_t));
 167             }
 168
 169           vlib_buffer_advance (i_b0, adv - icv_size);
 170
 171           if (is_ip6)
 172             {
 173               ih6_0 = (ip6_and_ah_header_t *) ih0;
 174               ip_hdr_size = sizeof (ip6_header_t);
 175               oh6_0 = vlib_buffer_get_current (i_b0);
 176
 177               hop_limit = ih6_0->ip6.hop_limit;
 178               ip_version_traffic_class_and_flow_label =
 179                 ih6_0->ip6.ip_version_traffic_class_and_flow_label;
 180               if (PREDICT_TRUE (sa0->is_tunnel))
 181                 {
 182                   next_hdr_type = IP_PROTOCOL_IPV6;
 183                 }
 184               else
 185                 {
 186                   next_hdr_type = ih6_0->ip6.protocol;
 187                   memmove (oh6_0, ih6_0, sizeof (ip6_header_t));
 188                 }
 189
 190               oh6_0->ip6.protocol = IP_PROTOCOL_IPSEC_AH;
 191               oh6_0->ip6.hop_limit = 0;
 192               oh6_0->ip6.ip_version_traffic_class_and_flow_label = 0x60;
 193               oh6_0->ah.reserved = 0;
 194               oh6_0->ah.nexthdr = next_hdr_type;
 195               oh6_0->ah.spi = clib_net_to_host_u32 (sa0->spi);
 196               oh6_0->ah.seq_no = clib_net_to_host_u32 (sa0->seq);
 197               oh6_0->ip6.payload_length =
 198                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, i_b0) -
 199                                       sizeof (ip6_header_t));
 200               oh6_0->ah.hdrlen =
 201                 (sizeof (ah_header_t) + icv_size + padding_len) / 4 - 2;
 202             }
 203           else
 204             {
 205               ip_hdr_size = sizeof (ip4_header_t);
 206               oh0 = vlib_buffer_get_current (i_b0);
 207               clib_memset (oh0, 0, sizeof (ip4_and_ah_header_t));
 208
 209               if (PREDICT_TRUE (sa0->is_tunnel))
 210                 {
 211                   next_hdr_type = IP_PROTOCOL_IP_IN_IP;
 212                 }
 213               else
 214                 {
 215                   next_hdr_type = ih0->ip4.protocol;
 216                   memmove (oh0, ih0, sizeof (ip4_header_t));
 217                 }
 218
 219               oh0->ip4.length =
 220                 clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, i_b0));
 221               oh0->ip4.ip_version_and_header_length = 0x45;
 222               oh0->ip4.fragment_id = 0;
 223               oh0->ip4.flags_and_fragment_offset = 0;
 224               oh0->ip4.ttl = 0;
 225               oh0->ip4.tos = 0;
 226               oh0->ip4.protocol = IP_PROTOCOL_IPSEC_AH;
 227               oh0->ah.spi = clib_net_to_host_u32 (sa0->spi);
 228               oh0->ah.seq_no = clib_net_to_host_u32 (sa0->seq);
 229               oh0->ip4.checksum = 0;
 230               oh0->ah.nexthdr = next_hdr_type;
 231               oh0->ah.hdrlen =
 232                 (sizeof (ah_header_t) + icv_size + padding_len) / 4 - 2;
 233             }
 234
 235
 236           if (PREDICT_TRUE (!is_ip6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 237             {
 238               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 239               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 240
 241               next0 = sa0->dpo[IPSEC_PROTOCOL_AH].dpoi_next_node;
 242               vnet_buffer (i_b0)->ip.adj_index[VLIB_TX] =
 243                 sa0->dpo[IPSEC_PROTOCOL_AH].dpoi_index;
 244             }
 245           else if (is_ip6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 246             {
 247               oh6_0->ip6.src_address.as_u64[0] =
 248                 sa0->tunnel_src_addr.ip6.as_u64[0];
 249               oh6_0->ip6.src_address.as_u64[1] =
 250                 sa0->tunnel_src_addr.ip6.as_u64[1];
 251               oh6_0->ip6.dst_address.as_u64[0] =
 252                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 253               oh6_0->ip6.dst_address.as_u64[1] =
 254                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 255
 256               next0 = sa0->dpo[IPSEC_PROTOCOL_AH].dpoi_next_node;
 257               vnet_buffer (i_b0)->ip.adj_index[VLIB_TX] =
 258                 sa0->dpo[IPSEC_PROTOCOL_AH].dpoi_index;
 259             }
 260
 261           u8 sig[64];
 262
 263           u8 *digest =
 264             vlib_buffer_get_current (i_b0) + ip_hdr_size +
 265             sizeof (ah_header_t);
 266           clib_memset (digest, 0, icv_size);
 267
 268           unsigned size = hmac_calc (vm, sa0, vlib_buffer_get_current (i_b0),
 269                                      i_b0->current_length, sig);
 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               ah_encrypt_trace_t *tr =
 295                 vlib_add_trace (vm, node, i_b0, sizeof (*tr));
 296               tr->spi = sa0->spi;
 297               tr->seq_lo = sa0->seq;
 298               tr->seq_hi = sa0->seq_hi;
 299               tr->integ_alg = sa0->integ_alg;
 300               tr->sa_index = sa_index0;
 301             }
 302
 303           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 304                                            to_next, n_left_to_next, i_bi0,
 305                                            next0);
 306         }
 307       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 308     }
 309   vlib_node_increment_counter (vm, node->node_index,
 310                                AH_ENCRYPT_ERROR_RX_PKTS,
 311                                from_frame->n_vectors);
 312
 313   return from_frame->n_vectors;
 314 }
 315
 316 VLIB_NODE_FN (ah4_encrypt_node) (vlib_main_t * vm,
 317                                  vlib_node_runtime_t * node,
 318                                  vlib_frame_t * from_frame)
 319 {
 320   return ah_encrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 321 }
 322
 323 /* *INDENT-OFF* */
 324 VLIB_REGISTER_NODE (ah4_encrypt_node) = {
 325   .name = "ah4-encrypt",
 326   .vector_size = sizeof (u32),
 327   .format_trace = format_ah_encrypt_trace,
 328   .type = VLIB_NODE_TYPE_INTERNAL,
 329
 330   .n_errors = ARRAY_LEN(ah_encrypt_error_strings),
 331   .error_strings = ah_encrypt_error_strings,
 332
 333   .n_next_nodes = AH_ENCRYPT_N_NEXT,
 334   .next_nodes = {
 335 #define _(s,n) [AH_ENCRYPT_NEXT_##s] = n,
 336     foreach_ah_encrypt_next
 337 #undef _
 338   },
 339 };
 340 /* *INDENT-ON* */
 341
 342 VLIB_NODE_FN (ah6_encrypt_node) (vlib_main_t * vm,
 343                                  vlib_node_runtime_t * node,
 344                                  vlib_frame_t * from_frame)
 345 {
 346   return ah_encrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 347 }
 348
 349 /* *INDENT-OFF* */
 350 VLIB_REGISTER_NODE (ah6_encrypt_node) = {
 351   .name = "ah6-encrypt",
 352   .vector_size = sizeof (u32),
 353   .format_trace = format_ah_encrypt_trace,
 354   .type = VLIB_NODE_TYPE_INTERNAL,
 355
 356   .n_errors = ARRAY_LEN(ah_encrypt_error_strings),
 357   .error_strings = ah_encrypt_error_strings,
 358
 359   .n_next_nodes = AH_ENCRYPT_N_NEXT,
 360   .next_nodes = {
 361 #define _(s,n) [AH_ENCRYPT_NEXT_##s] = n,
 362     foreach_ah_encrypt_next
 363 #undef _
 364   },
 365 };
 366 /* *INDENT-ON* */
 367
 368 /*
 369  * fd.io coding-style-patch-verification: ON
 370  *
 371  * Local Variables:
 372  * eval: (c-set-style "gnu")
 373  * End:
 374  */