src/plugins/nat/nat44_classify.c

   1 /*
   2  * Copyright (c) 2018 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 /**
  16  * @file
  17  * @brief Classify for one armed NAT44 (in+out interface)
  18  */
  19
  20 #include <vlib/vlib.h>
  21 #include <vnet/vnet.h>
  22 #include <vnet/fib/ip4_fib.h>
  23 #include <nat/nat.h>
  24 #include <nat/nat_reass.h>
  25 #include <nat/nat_inlines.h>
  26
  27 vlib_node_registration_t nat44_classify_node;
  28 vlib_node_registration_t nat44_ed_classify_node;
  29 vlib_node_registration_t nat44_det_classify_node;
  30 vlib_node_registration_t nat44_handoff_classify_node;
  31
  32 #define foreach_nat44_classify_error                      \
  33 _(MAX_REASS, "Maximum reassemblies exceeded")             \
  34 _(MAX_FRAG, "Maximum fragments per reassembly exceeded")
  35
  36 typedef enum
  37 {
  38 #define _(sym,str) NAT44_CLASSIFY_ERROR_##sym,
  39   foreach_nat44_classify_error
  40 #undef _
  41     NAT44_CLASSIFY_N_ERROR,
  42 } nat44_classify_error_t;
  43
  44 static char *nat44_classify_error_strings[] = {
  45 #define _(sym,string) string,
  46   foreach_nat44_classify_error
  47 #undef _
  48 };
  49
  50 typedef enum
  51 {
  52   NAT44_CLASSIFY_NEXT_IN2OUT,
  53   NAT44_CLASSIFY_NEXT_OUT2IN,
  54   NAT44_CLASSIFY_NEXT_DROP,
  55   NAT44_CLASSIFY_N_NEXT,
  56 } nat44_classify_next_t;
  57
  58 typedef struct
  59 {
  60   u8 next_in2out;
  61   u8 cached;
  62 } nat44_classify_trace_t;
  63
  64 static u8 *
  65 format_nat44_classify_trace (u8 * s, va_list * args)
  66 {
  67   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  68   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  69   nat44_classify_trace_t *t = va_arg (*args, nat44_classify_trace_t *);
  70   char *next;
  71
  72   if (t->cached)
  73     s = format (s, "nat44-classify: fragment cached");
  74   else
  75     {
  76       next = t->next_in2out ? "nat44-in2out" : "nat44-out2in";
  77       s = format (s, "nat44-classify: next %s", next);
  78     }
  79
  80   return s;
  81 }
  82
  83 static inline uword
  84 nat44_classify_node_fn_inline (vlib_main_t * vm,
  85                                vlib_node_runtime_t * node,
  86                                vlib_frame_t * frame, int is_ed)
  87 {
  88   u32 n_left_from, *from, *to_next;
  89   nat44_classify_next_t next_index;
  90   snat_main_t *sm = &snat_main;
  91   snat_static_mapping_t *m;
  92   u32 thread_index = vm->thread_index;
  93   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
  94   u32 *fragments_to_drop = 0;
  95   u32 *fragments_to_loopback = 0;
  96
  97   from = vlib_frame_vector_args (frame);
  98   n_left_from = frame->n_vectors;
  99   next_index = node->cached_next_index;
 100
 101   while (n_left_from > 0)
 102     {
 103       u32 n_left_to_next;
 104
 105       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 106
 107       while (n_left_from > 0 && n_left_to_next > 0)
 108         {
 109           u32 bi0;
 110           vlib_buffer_t *b0;
 111           u32 next0 = NAT44_CLASSIFY_NEXT_IN2OUT, sw_if_index0, rx_fib_index0;
 112           ip4_header_t *ip0;
 113           snat_address_t *ap;
 114           snat_session_key_t m_key0;
 115           clib_bihash_kv_8_8_t kv0, value0;
 116           clib_bihash_kv_16_8_t ed_kv0, ed_value0;
 117           udp_header_t *udp0;
 118           nat_reass_ip4_t *reass0;
 119           u8 cached0 = 0;
 120
 121           /* speculatively enqueue b0 to the current next frame */
 122           bi0 = from[0];
 123           to_next[0] = bi0;
 124           from += 1;
 125           to_next += 1;
 126           n_left_from -= 1;
 127           n_left_to_next -= 1;
 128
 129           b0 = vlib_get_buffer (vm, bi0);
 130           ip0 = vlib_buffer_get_current (b0);
 131           udp0 = ip4_next_header (ip0);
 132
 133           if (is_ed && ip0->protocol != IP_PROTOCOL_ICMP)
 134             {
 135               if (!ip4_is_fragment (ip0) || ip4_is_first_fragment (ip0))
 136                 {
 137                   /* process leading fragment/whole packet (with L4 header) */
 138                   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 139                   rx_fib_index0 =
 140                     fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
 141                                                          sw_if_index0);
 142                   make_ed_kv (&ed_kv0, &ip0->src_address, &ip0->dst_address,
 143                               ip0->protocol, rx_fib_index0, udp0->src_port,
 144                               udp0->dst_port);
 145                   if (ip4_is_fragment (ip0))
 146                     {
 147                       reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
 148                                                              ip0->dst_address,
 149                                                              ip0->fragment_id,
 150                                                              ip0->protocol,
 151                                                              1,
 152                                                              &fragments_to_drop);
 153                       if (PREDICT_FALSE (!reass0))
 154                         {
 155                           next0 = NAT44_CLASSIFY_NEXT_DROP;
 156                           b0->error =
 157                             node->errors[NAT44_CLASSIFY_ERROR_MAX_REASS];
 158                           nat_log_notice ("maximum reassemblies exceeded");
 159                           goto enqueue0;
 160                         }
 161                       if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &ed_kv0,
 162                                                     &ed_value0))
 163                         {
 164                           /* session exists so classify as IN2OUT,
 165                            * save this information for future fragments and set
 166                            * past fragments to be looped over and reprocessed */
 167                           reass0->sess_index = ed_value0.value;
 168                           reass0->classify_next =
 169                             NAT_REASS_IP4_CLASSIFY_NEXT_IN2OUT;
 170                           nat_ip4_reass_get_frags (reass0,
 171                                                    &fragments_to_loopback);
 172                           goto enqueue0;
 173                         }
 174                       else
 175                         {
 176                           /* session doesn't exist so continue in the code,
 177                            * save this information for future fragments and set
 178                            * past fragments to be looped over and reprocessed */
 179                           reass0->flags |=
 180                             NAT_REASS_FLAG_CLASSIFY_ED_CONTINUE;
 181                           nat_ip4_reass_get_frags (reass0,
 182                                                    &fragments_to_loopback);
 183                         }
 184                     }
 185                   else
 186                     {
 187                       /* process whole packet */
 188                       if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &ed_kv0,
 189                                                     &ed_value0))
 190                         goto enqueue0;
 191                       /* session doesn't exist so continue in code */
 192                     }
 193                 }
 194               else
 195                 {
 196                   /* process non-first fragment */
 197                   reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
 198                                                          ip0->dst_address,
 199                                                          ip0->fragment_id,
 200                                                          ip0->protocol,
 201                                                          1,
 202                                                          &fragments_to_drop);
 203                   if (PREDICT_FALSE (!reass0))
 204                     {
 205                       next0 = NAT44_CLASSIFY_NEXT_DROP;
 206                       b0->error =
 207                         node->errors[NAT44_CLASSIFY_ERROR_MAX_REASS];
 208                       nat_log_notice ("maximum reassemblies exceeded");
 209                       goto enqueue0;
 210                     }
 211                   /* check if first fragment has arrived */
 212                   if (reass0->classify_next == NAT_REASS_IP4_CLASSIFY_NONE &&
 213                       !(reass0->flags & NAT_REASS_FLAG_CLASSIFY_ED_CONTINUE))
 214                     {
 215                       /* first fragment still hasn't arrived, cache this fragment */
 216                       if (nat_ip4_reass_add_fragment (reass0, bi0,
 217                                                       &fragments_to_drop))
 218                         {
 219                           b0->error =
 220                             node->errors[NAT44_CLASSIFY_ERROR_MAX_FRAG];
 221                           nat_log_notice
 222                             ("maximum fragments per reassembly exceeded");
 223                           next0 = NAT44_CLASSIFY_NEXT_DROP;
 224                           goto enqueue0;
 225                         }
 226                       cached0 = 1;
 227                       goto enqueue0;
 228                     }
 229                   if (reass0->classify_next ==
 230                       NAT_REASS_IP4_CLASSIFY_NEXT_IN2OUT)
 231                     goto enqueue0;
 232                   /* flag NAT_REASS_FLAG_CLASSIFY_ED_CONTINUE is set
 233                    * so keep the default next0 and continue in code to
 234                    * potentially find other classification for this packet */
 235                 }
 236             }
 237
 238           /* *INDENT-OFF* */
 239           vec_foreach (ap, sm->addresses)
 240             {
 241               if (ip0->dst_address.as_u32 == ap->addr.as_u32)
 242                 {
 243                   next0 = NAT44_CLASSIFY_NEXT_OUT2IN;
 244                   goto enqueue0;
 245                 }
 246             }
 247           /* *INDENT-ON* */
 248
 249           if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
 250             {
 251               m_key0.addr = ip0->dst_address;
 252               m_key0.port = 0;
 253               m_key0.protocol = 0;
 254               m_key0.fib_index = 0;
 255               kv0.key = m_key0.as_u64;
 256               /* try to classify the fragment based on IP header alone */
 257               if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external,
 258                                            &kv0, &value0))
 259                 {
 260                   m = pool_elt_at_index (sm->static_mappings, value0.value);
 261                   if (m->local_addr.as_u32 != m->external_addr.as_u32)
 262                     next0 = NAT44_CLASSIFY_NEXT_OUT2IN;
 263                   goto enqueue0;
 264                 }
 265               if (!ip4_is_fragment (ip0) || ip4_is_first_fragment (ip0))
 266                 {
 267                   /* process leading fragment/whole packet (with L4 header) */
 268                   m_key0.port = clib_net_to_host_u16 (udp0->dst_port);
 269                   m_key0.protocol = ip_proto_to_snat_proto (ip0->protocol);
 270                   kv0.key = m_key0.as_u64;
 271                   if (!clib_bihash_search_8_8
 272                       (&sm->static_mapping_by_external, &kv0, &value0))
 273                     {
 274                       m =
 275                         pool_elt_at_index (sm->static_mappings, value0.value);
 276                       if (m->local_addr.as_u32 != m->external_addr.as_u32)
 277                         next0 = NAT44_CLASSIFY_NEXT_OUT2IN;
 278                     }
 279                   if (ip4_is_fragment (ip0))
 280                     {
 281                       reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
 282                                                              ip0->dst_address,
 283                                                              ip0->fragment_id,
 284                                                              ip0->protocol,
 285                                                              1,
 286                                                              &fragments_to_drop);
 287                       if (PREDICT_FALSE (!reass0))
 288                         {
 289                           next0 = NAT44_CLASSIFY_NEXT_DROP;
 290                           b0->error =
 291                             node->errors[NAT44_CLASSIFY_ERROR_MAX_REASS];
 292                           nat_log_notice ("maximum reassemblies exceeded");
 293                           goto enqueue0;
 294                         }
 295                       /* save classification for future fragments and set past
 296                        * fragments to be looped over and reprocessed */
 297                       if (next0 == NAT44_CLASSIFY_NEXT_OUT2IN)
 298                         reass0->classify_next =
 299                           NAT_REASS_IP4_CLASSIFY_NEXT_OUT2IN;
 300                       else
 301                         reass0->classify_next =
 302                           NAT_REASS_IP4_CLASSIFY_NEXT_IN2OUT;
 303                       nat_ip4_reass_get_frags (reass0,
 304                                                &fragments_to_loopback);
 305                     }
 306                 }
 307               else
 308                 {
 309                   /* process non-first fragment */
 310                   reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
 311                                                          ip0->dst_address,
 312                                                          ip0->fragment_id,
 313                                                          ip0->protocol,
 314                                                          1,
 315                                                          &fragments_to_drop);
 316                   if (PREDICT_FALSE (!reass0))
 317                     {
 318                       next0 = NAT44_CLASSIFY_NEXT_DROP;
 319                       b0->error =
 320                         node->errors[NAT44_CLASSIFY_ERROR_MAX_REASS];
 321                       nat_log_notice ("maximum reassemblies exceeded");
 322                       goto enqueue0;
 323                     }
 324                   if (reass0->classify_next == NAT_REASS_IP4_CLASSIFY_NONE)
 325                     /* first fragment still hasn't arrived */
 326                     {
 327                       if (nat_ip4_reass_add_fragment (reass0, bi0,
 328                                                       &fragments_to_drop))
 329                         {
 330                           b0->error =
 331                             node->errors[NAT44_CLASSIFY_ERROR_MAX_FRAG];
 332                           nat_log_notice
 333                             ("maximum fragments per reassembly exceeded");
 334                           next0 = NAT44_CLASSIFY_NEXT_DROP;
 335                           goto enqueue0;
 336                         }
 337                       cached0 = 1;
 338                       goto enqueue0;
 339                     }
 340                   else if (reass0->classify_next ==
 341                            NAT_REASS_IP4_CLASSIFY_NEXT_OUT2IN)
 342                     next0 = NAT44_CLASSIFY_NEXT_OUT2IN;
 343                   else if (reass0->classify_next ==
 344                            NAT_REASS_IP4_CLASSIFY_NEXT_IN2OUT)
 345                     next0 = NAT44_CLASSIFY_NEXT_IN2OUT;
 346                 }
 347             }
 348
 349         enqueue0:
 350           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 351                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 352             {
 353               nat44_classify_trace_t *t =
 354                 vlib_add_trace (vm, node, b0, sizeof (*t));
 355               t->cached = cached0;
 356               if (!cached0)
 357                 t->next_in2out = next0 == NAT44_CLASSIFY_NEXT_IN2OUT ? 1 : 0;
 358             }
 359
 360           if (cached0)
 361             {
 362               n_left_to_next++;
 363               to_next--;
 364             }
 365           else
 366             /* verify speculative enqueue, maybe switch current next frame */
 367             vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 368                                              to_next, n_left_to_next,
 369                                              bi0, next0);
 370
 371           if (n_left_from == 0 && vec_len (fragments_to_loopback))
 372             {
 373               from = vlib_frame_vector_args (frame);
 374               u32 len = vec_len (fragments_to_loopback);
 375               if (len <= VLIB_FRAME_SIZE)
 376                 {
 377                   clib_memcpy_fast (from, fragments_to_loopback,
 378                                     sizeof (u32) * len);
 379                   n_left_from = len;
 380                   vec_reset_length (fragments_to_loopback);
 381                 }
 382               else
 383                 {
 384                   clib_memcpy_fast (from, fragments_to_loopback +
 385                                     (len - VLIB_FRAME_SIZE),
 386                                     sizeof (u32) * VLIB_FRAME_SIZE);
 387                   n_left_from = VLIB_FRAME_SIZE;
 388                   _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
 389                 }
 390             }
 391         }
 392
 393       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 394     }
 395
 396   nat_send_all_to_node (vm, fragments_to_drop, node, 0,
 397                         NAT44_CLASSIFY_NEXT_DROP);
 398
 399   vec_free (fragments_to_drop);
 400
 401   return frame->n_vectors;
 402 }
 403
 404 static uword
 405 nat44_classify_node_fn (vlib_main_t * vm,
 406                         vlib_node_runtime_t * node, vlib_frame_t * frame)
 407 {
 408   return nat44_classify_node_fn_inline (vm, node, frame, 0);
 409 }
 410
 411 /* *INDENT-OFF* */
 412 VLIB_REGISTER_NODE (nat44_classify_node) = {
 413   .function = nat44_classify_node_fn,
 414   .name = "nat44-classify",
 415   .vector_size = sizeof (u32),
 416   .format_trace = format_nat44_classify_trace,
 417   .type = VLIB_NODE_TYPE_INTERNAL,
 418   .n_errors = ARRAY_LEN(nat44_classify_error_strings),
 419   .error_strings = nat44_classify_error_strings,
 420   .n_next_nodes = NAT44_CLASSIFY_N_NEXT,
 421   .next_nodes = {
 422     [NAT44_CLASSIFY_NEXT_IN2OUT] = "nat44-in2out",
 423     [NAT44_CLASSIFY_NEXT_OUT2IN] = "nat44-out2in",
 424     [NAT44_CLASSIFY_NEXT_DROP] = "error-drop",
 425   },
 426 };
 427 /* *INDENT-ON* */
 428
 429 VLIB_NODE_FUNCTION_MULTIARCH (nat44_classify_node, nat44_classify_node_fn);
 430 static uword
 431 nat44_ed_classify_node_fn (vlib_main_t * vm,
 432                            vlib_node_runtime_t * node, vlib_frame_t * frame)
 433 {
 434   return nat44_classify_node_fn_inline (vm, node, frame, 1);
 435 }
 436
 437 /* *INDENT-OFF* */
 438 VLIB_REGISTER_NODE (nat44_ed_classify_node) = {
 439   .function = nat44_ed_classify_node_fn,
 440   .name = "nat44-ed-classify",
 441   .vector_size = sizeof (u32),
 442   .format_trace = format_nat44_classify_trace,
 443   .type = VLIB_NODE_TYPE_INTERNAL,
 444   .n_next_nodes = NAT44_CLASSIFY_N_NEXT,
 445   .next_nodes = {
 446     [NAT44_CLASSIFY_NEXT_IN2OUT] = "nat44-ed-in2out",
 447     [NAT44_CLASSIFY_NEXT_OUT2IN] = "nat44-ed-out2in",
 448     [NAT44_CLASSIFY_NEXT_DROP] = "error-drop",
 449   },
 450 };
 451 /* *INDENT-ON* */
 452
 453 VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_classify_node,
 454                               nat44_ed_classify_node_fn);
 455
 456 static uword
 457 nat44_det_classify_node_fn (vlib_main_t * vm,
 458                             vlib_node_runtime_t * node, vlib_frame_t * frame)
 459 {
 460   return nat44_classify_node_fn_inline (vm, node, frame, 0);
 461 }
 462
 463 /* *INDENT-OFF* */
 464 VLIB_REGISTER_NODE (nat44_det_classify_node) = {
 465   .function = nat44_det_classify_node_fn,
 466   .name = "nat44-det-classify",
 467   .vector_size = sizeof (u32),
 468   .format_trace = format_nat44_classify_trace,
 469   .type = VLIB_NODE_TYPE_INTERNAL,
 470   .n_next_nodes = NAT44_CLASSIFY_N_NEXT,
 471   .next_nodes = {
 472     [NAT44_CLASSIFY_NEXT_IN2OUT] = "nat44-det-in2out",
 473     [NAT44_CLASSIFY_NEXT_OUT2IN] = "nat44-det-out2in",
 474     [NAT44_CLASSIFY_NEXT_DROP] = "error-drop",
 475   },
 476 };
 477 /* *INDENT-ON* */
 478
 479 VLIB_NODE_FUNCTION_MULTIARCH (nat44_det_classify_node,
 480                               nat44_det_classify_node_fn);
 481
 482 static uword
 483 nat44_handoff_classify_node_fn (vlib_main_t * vm,
 484                                 vlib_node_runtime_t * node,
 485                                 vlib_frame_t * frame)
 486 {
 487   return nat44_classify_node_fn_inline (vm, node, frame, 0);
 488 }
 489
 490 /* *INDENT-OFF* */
 491 VLIB_REGISTER_NODE (nat44_handoff_classify_node) = {
 492   .function = nat44_handoff_classify_node_fn,
 493   .name = "nat44-handoff-classify",
 494   .vector_size = sizeof (u32),
 495   .format_trace = format_nat44_classify_trace,
 496   .type = VLIB_NODE_TYPE_INTERNAL,
 497   .n_next_nodes = NAT44_CLASSIFY_N_NEXT,
 498   .next_nodes = {
 499     [NAT44_CLASSIFY_NEXT_IN2OUT] = "nat44-in2out-worker-handoff",
 500     [NAT44_CLASSIFY_NEXT_OUT2IN] = "nat44-out2in-worker-handoff",
 501     [NAT44_CLASSIFY_NEXT_DROP] = "error-drop",
 502   },
 503 };
 504
 505 VLIB_NODE_FUNCTION_MULTIARCH (nat44_handoff_classify_node,
 506                               nat44_handoff_classify_node_fn);
 507 /* *INDENT-ON* */
 508
 509 /*
 510  * fd.io coding-style-patch-verification: ON
 511  *
 512  * Local Variables:
 513  * eval: (c-set-style "gnu")
 514  * End:
 515  */