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 #define _(v, s) AH_ENCRYPT_NEXT_##v,
  33 typedef enum
  34 {
  35   foreach_ah_encrypt_next
  36 #undef _
  37     AH_ENCRYPT_N_NEXT,
  38 } ah_encrypt_next_t;
  39
  40 #define foreach_ah_encrypt_error                   \
  41  _(RX_PKTS, "AH pkts received")                    \
  42  _(SEQ_CYCLED, "sequence number cycled")
  43
  44
  45 typedef enum
  46 {
  47 #define _(sym,str) AH_ENCRYPT_ERROR_##sym,
  48   foreach_ah_encrypt_error
  49 #undef _
  50     AH_ENCRYPT_N_ERROR,
  51 } ah_encrypt_error_t;
  52
  53 static char *ah_encrypt_error_strings[] = {
  54 #define _(sym,string) string,
  55   foreach_ah_encrypt_error
  56 #undef _
  57 };
  58
  59 vlib_node_registration_t ah_encrypt_node;
  60
  61 typedef struct
  62 {
  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: spi %u seq %u integrity %U",
  77               t->spi, t->seq, format_ipsec_integ_alg, t->integ_alg);
  78   return s;
  79 }
  80
  81 static uword
  82 ah_encrypt_node_fn (vlib_main_t * vm,
  83                     vlib_node_runtime_t * node, vlib_frame_t * from_frame)
  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 is_ipv6;
 108           u8 ip_hdr_size;
 109           u8 next_hdr_type;
 110           u8 transport_mode = 0;
 111           u8 tos = 0;
 112           u8 ttl = 0;
 113           u8 hop_limit = 0;
 114           u32 ip_version_traffic_class_and_flow_label = 0;
 115
 116           i_bi0 = from[0];
 117           from += 1;
 118           n_left_from -= 1;
 119           n_left_to_next -= 1;
 120           next0 = AH_ENCRYPT_NEXT_DROP;
 121
 122           i_b0 = vlib_get_buffer (vm, i_bi0);
 123           to_next[0] = i_bi0;
 124           to_next += 1;
 125           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 126           sa0 = pool_elt_at_index (im->sad, sa_index0);
 127
 128           if (PREDICT_FALSE (esp_seq_advance (sa0)))
 129             {
 130               clib_warning ("sequence number counter has cycled SPI %u",
 131                             sa0->spi);
 132               vlib_node_increment_counter (vm, ah_encrypt_node.index,
 133                                            AH_ENCRYPT_ERROR_SEQ_CYCLED, 1);
 134               //TODO need to confirm if below is needed
 135               to_next[0] = i_bi0;
 136               to_next += 1;
 137               goto trace;
 138             }
 139
 140
 141           sa0->total_data_size += i_b0->current_length;
 142
 143           ssize_t adv;
 144           ih0 = vlib_buffer_get_current (i_b0);
 145           ttl = ih0->ip4.ttl;
 146           tos = ih0->ip4.tos;
 147
 148           is_ipv6 = (ih0->ip4.ip_version_and_header_length & 0xF0) == 0x60;
 149           /* is ipv6 */
 150           if (PREDICT_TRUE (sa0->is_tunnel))
 151             {
 152               if (PREDICT_TRUE (!is_ipv6))
 153                 adv = -sizeof (ip4_and_ah_header_t);
 154               else
 155                 adv = -sizeof (ip6_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_ipv6);
 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 (PREDICT_FALSE (is_ipv6))
 180             {                   /* is ipv6 */
 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               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
 245               (!is_ipv6 && sa0->is_tunnel && !sa0->is_tunnel_ip6))
 246             {
 247               oh0->ip4.src_address.as_u32 = sa0->tunnel_src_addr.ip4.as_u32;
 248               oh0->ip4.dst_address.as_u32 = sa0->tunnel_dst_addr.ip4.as_u32;
 249
 250               next0 = AH_ENCRYPT_NEXT_IP4_LOOKUP;
 251               vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 252             }
 253           else if (is_ipv6 && sa0->is_tunnel && sa0->is_tunnel_ip6)
 254             {
 255               oh6_0->ip6.src_address.as_u64[0] =
 256                 sa0->tunnel_src_addr.ip6.as_u64[0];
 257               oh6_0->ip6.src_address.as_u64[1] =
 258                 sa0->tunnel_src_addr.ip6.as_u64[1];
 259               oh6_0->ip6.dst_address.as_u64[0] =
 260                 sa0->tunnel_dst_addr.ip6.as_u64[0];
 261               oh6_0->ip6.dst_address.as_u64[1] =
 262                 sa0->tunnel_dst_addr.ip6.as_u64[1];
 263
 264               next0 = AH_ENCRYPT_NEXT_IP6_LOOKUP;
 265               vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 266             }
 267           else
 268             {
 269               transport_mode = 1;
 270               next0 = AH_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 271             }
 272
 273           u8 sig[64];
 274           memset (sig, 0, sizeof (sig));
 275           u8 *digest =
 276             vlib_buffer_get_current (i_b0) + ip_hdr_size +
 277             sizeof (ah_header_t);
 278           memset (digest, 0, icv_size);
 279
 280           unsigned size = hmac_calc (sa0->integ_alg, sa0->integ_key,
 281                                      sa0->integ_key_len,
 282                                      vlib_buffer_get_current (i_b0),
 283                                      i_b0->current_length, sig, sa0->use_esn,
 284                                      sa0->seq_hi);
 285
 286           memcpy (digest, sig, size);
 287           if (PREDICT_FALSE (is_ipv6))
 288             {
 289               oh6_0->ip6.hop_limit = hop_limit;
 290               oh6_0->ip6.ip_version_traffic_class_and_flow_label =
 291                 ip_version_traffic_class_and_flow_label;
 292             }
 293           else
 294             {
 295               oh0->ip4.ttl = ttl;
 296               oh0->ip4.tos = tos;
 297               oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
 298             }
 299
 300           if (transport_mode)
 301             vlib_buffer_advance (i_b0, -sizeof (ethernet_header_t));
 302
 303         trace:
 304           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 305             {
 306               i_b0->flags |= VLIB_BUFFER_IS_TRACED;
 307               ah_encrypt_trace_t *tr =
 308                 vlib_add_trace (vm, node, i_b0, sizeof (*tr));
 309               tr->spi = sa0->spi;
 310               tr->seq = sa0->seq - 1;
 311               tr->integ_alg = sa0->integ_alg;
 312             }
 313
 314           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 315                                            to_next, n_left_to_next, i_bi0,
 316                                            next0);
 317         }
 318       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 319     }
 320   vlib_node_increment_counter (vm, ah_encrypt_node.index,
 321                                AH_ENCRYPT_ERROR_RX_PKTS,
 322                                from_frame->n_vectors);
 323
 324   return from_frame->n_vectors;
 325 }
 326
 327
 328 /* *INDENT-OFF* */
 329 VLIB_REGISTER_NODE (ah_encrypt_node) = {
 330   .function = ah_encrypt_node_fn,
 331   .name = "ah-encrypt",
 332   .vector_size = sizeof (u32),
 333   .format_trace = format_ah_encrypt_trace,
 334   .type = VLIB_NODE_TYPE_INTERNAL,
 335
 336   .n_errors = ARRAY_LEN(ah_encrypt_error_strings),
 337   .error_strings = ah_encrypt_error_strings,
 338
 339   .n_next_nodes = AH_ENCRYPT_N_NEXT,
 340   .next_nodes = {
 341 #define _(s,n) [AH_ENCRYPT_NEXT_##s] = n,
 342     foreach_ah_encrypt_next
 343 #undef _
 344   },
 345 };
 346 /* *INDENT-ON* */
 347
 348 VLIB_NODE_FUNCTION_MULTIARCH (ah_encrypt_node, ah_encrypt_node_fn)
 349 /*
 350  * fd.io coding-style-patch-verification: ON
 351  *
 352  * Local Variables:
 353  * eval: (c-set-style "gnu")
 354  * End:
 355  */