src/plugins/nat/nat_det_out2in.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 Deterministic/CGN NAT44 outside to inside network translation
  18  */
  19
  20 #include <vlib/vlib.h>
  21 #include <vnet/vnet.h>
  22 #include <vnet/ip/ip.h>
  23 #include <vnet/fib/ip4_fib.h>
  24 #include <vppinfra/error.h>
  25 #include <vppinfra/elog.h>
  26 #include <nat/nat.h>
  27 #include <nat/nat_det.h>
  28 #include <nat/nat_inlines.h>
  29
  30 typedef enum
  31 {
  32   NAT_DET_OUT2IN_NEXT_DROP,
  33   NAT_DET_OUT2IN_NEXT_LOOKUP,
  34   NAT_DET_OUT2IN_NEXT_ICMP_ERROR,
  35   NAT_DET_OUT2IN_N_NEXT,
  36 } nat_det_out2in_next_t;
  37
  38 typedef struct
  39 {
  40   u32 sw_if_index;
  41   u32 next_index;
  42   u32 session_index;
  43 } nat_det_out2in_trace_t;
  44
  45 #define foreach_nat_det_out2in_error                       \
  46 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
  47 _(NO_TRANSLATION, "No translation")                     \
  48 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  49 _(OUT2IN_PACKETS, "Good out2in packets processed")
  50
  51 typedef enum
  52 {
  53 #define _(sym,str) NAT_DET_OUT2IN_ERROR_##sym,
  54   foreach_nat_det_out2in_error
  55 #undef _
  56     SNAT_OUT2IN_N_ERROR,
  57 } nat_det_out2in_error_t;
  58
  59 static char *nat_det_out2in_error_strings[] = {
  60 #define _(sym,string) string,
  61   foreach_nat_det_out2in_error
  62 #undef _
  63 };
  64
  65 static u8 *
  66 format_nat_det_out2in_trace (u8 * s, va_list * args)
  67 {
  68   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  69   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  70   nat_det_out2in_trace_t *t = va_arg (*args, nat_det_out2in_trace_t *);
  71
  72   s =
  73     format (s,
  74             "NAT_DET_OUT2IN: sw_if_index %d, next index %d, session index %d",
  75             t->sw_if_index, t->next_index, t->session_index);
  76   return s;
  77 }
  78
  79 #ifndef CLIB_MARCH_VARIANT
  80 /**
  81  * Get address and port values to be used for ICMP packet translation
  82  * and create session if needed
  83  *
  84  * @param[in,out] sm             NAT main
  85  * @param[in,out] node           NAT node runtime
  86  * @param[in] thread_index       thread index
  87  * @param[in,out] b0             buffer containing packet to be translated
  88  * @param[in,out] ip0            ip header
  89  * @param[out] p_proto           protocol used for matching
  90  * @param[out] p_value           address and port after NAT translation
  91  * @param[out] p_dont_translate  if packet should not be translated
  92  * @param d                      optional parameter
  93  * @param e                      optional parameter
  94  */
  95 u32
  96 icmp_match_out2in_det (snat_main_t * sm, vlib_node_runtime_t * node,
  97                        u32 thread_index, vlib_buffer_t * b0,
  98                        ip4_header_t * ip0, ip4_address_t * addr,
  99                        u16 * port, u32 * fib_index,
 100                        nat_protocol_t * proto, void *d, void *e,
 101                        u8 * dont_translate)
 102 {
 103   icmp46_header_t *icmp0;
 104   u32 sw_if_index0;
 105   u8 protocol;
 106   snat_det_out_key_t key0;
 107   u32 next0 = ~0;
 108   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 109   ip4_header_t *inner_ip0;
 110   void *l4_header = 0;
 111   icmp46_header_t *inner_icmp0;
 112   snat_det_map_t *dm0 = 0;
 113   ip4_address_t new_addr0 = { {0} };
 114   snat_det_session_t *ses0 = 0;
 115   ip4_address_t out_addr;
 116   *dont_translate = 0;
 117
 118   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 119   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 120   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 121
 122   if (!icmp_type_is_error_message
 123       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
 124     {
 125       protocol = NAT_PROTOCOL_ICMP;
 126       key0.ext_host_addr = ip0->src_address;
 127       key0.ext_host_port = 0;
 128       key0.out_port = vnet_buffer (b0)->ip.reass.l4_src_port;
 129       out_addr = ip0->dst_address;
 130     }
 131   else
 132     {
 133       /* if error message, then it's not fragmented and we can access it */
 134       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 135       l4_header = ip4_next_header (inner_ip0);
 136       protocol = ip_proto_to_nat_proto (inner_ip0->protocol);
 137       key0.ext_host_addr = inner_ip0->dst_address;
 138       out_addr = inner_ip0->src_address;
 139       switch (protocol)
 140         {
 141         case NAT_PROTOCOL_ICMP:
 142           inner_icmp0 = (icmp46_header_t *) l4_header;
 143           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 144           key0.ext_host_port = 0;
 145           key0.out_port = inner_echo0->identifier;
 146           break;
 147         case NAT_PROTOCOL_UDP:
 148         case NAT_PROTOCOL_TCP:
 149           key0.ext_host_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 150           key0.out_port = ((tcp_udp_header_t *) l4_header)->src_port;
 151           break;
 152         default:
 153           b0->error = node->errors[NAT_DET_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 154           next0 = NAT_DET_OUT2IN_NEXT_DROP;
 155           goto out;
 156         }
 157     }
 158
 159   dm0 = snat_det_map_by_out (sm, &out_addr);
 160   if (PREDICT_FALSE (!dm0))
 161     {
 162       /* Don't NAT packet aimed at the intfc address */
 163       if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 164                                             ip0->dst_address.as_u32)))
 165         {
 166           *dont_translate = 1;
 167           goto out;
 168         }
 169       nat_log_info ("unknown dst address:  %U",
 170                     format_ip4_address, &ip0->dst_address);
 171       goto out;
 172     }
 173
 174   snat_det_reverse (dm0, &ip0->dst_address,
 175                     clib_net_to_host_u16 (key0.out_port), &new_addr0);
 176
 177   ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
 178   if (PREDICT_FALSE (!ses0))
 179     {
 180       /* Don't NAT packet aimed at the intfc address */
 181       if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 182                                             ip0->dst_address.as_u32)))
 183         {
 184           *dont_translate = 1;
 185           goto out;
 186         }
 187       nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 188                     format_ip4_address, &key0.ext_host_addr,
 189                     clib_net_to_host_u16 (key0.ext_host_port),
 190                     format_ip4_address, &out_addr,
 191                     clib_net_to_host_u16 (key0.out_port),
 192                     format_ip4_address, &new_addr0);
 193       b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 194       next0 = NAT_DET_OUT2IN_NEXT_DROP;
 195       goto out;
 196     }
 197
 198   if (PREDICT_FALSE
 199       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
 200        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 201                                        reass.icmp_type_or_tcp_flags)))
 202     {
 203       b0->error = node->errors[NAT_DET_OUT2IN_ERROR_BAD_ICMP_TYPE];
 204       next0 = NAT_DET_OUT2IN_NEXT_DROP;
 205       goto out;
 206     }
 207
 208   goto out;
 209
 210 out:
 211   *proto = protocol;
 212   if (ses0)
 213     {
 214       *addr = new_addr0;
 215       *fib_index = sm->inside_fib_index;
 216       *port = ses0->in_port;
 217     }
 218   if (d)
 219     *(snat_det_session_t **) d = ses0;
 220   if (e)
 221     *(snat_det_map_t **) e = dm0;
 222   return next0;
 223 }
 224 #endif
 225
 226 VLIB_NODE_FN (snat_det_out2in_node) (vlib_main_t * vm,
 227                                      vlib_node_runtime_t * node,
 228                                      vlib_frame_t * frame)
 229 {
 230   u32 n_left_from, *from, *to_next;
 231   nat_det_out2in_next_t next_index;
 232   u32 pkts_processed = 0;
 233   snat_main_t *sm = &snat_main;
 234   u32 thread_index = vm->thread_index;
 235
 236   from = vlib_frame_vector_args (frame);
 237   n_left_from = frame->n_vectors;
 238   next_index = node->cached_next_index;
 239
 240   while (n_left_from > 0)
 241     {
 242       u32 n_left_to_next;
 243
 244       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 245
 246       while (n_left_from >= 4 && n_left_to_next >= 2)
 247         {
 248           u32 bi0, bi1;
 249           vlib_buffer_t *b0, *b1;
 250           u32 next0 = NAT_DET_OUT2IN_NEXT_LOOKUP;
 251           u32 next1 = NAT_DET_OUT2IN_NEXT_LOOKUP;
 252           u32 sw_if_index0, sw_if_index1;
 253           ip4_header_t *ip0, *ip1;
 254           ip_csum_t sum0, sum1;
 255           ip4_address_t new_addr0, old_addr0, new_addr1, old_addr1;
 256           u16 new_port0, old_port0, old_port1, new_port1;
 257           udp_header_t *udp0, *udp1;
 258           tcp_header_t *tcp0, *tcp1;
 259           u32 proto0, proto1;
 260           snat_det_out_key_t key0, key1;
 261           snat_det_map_t *dm0, *dm1;
 262           snat_det_session_t *ses0 = 0, *ses1 = 0;
 263           u32 rx_fib_index0, rx_fib_index1;
 264           icmp46_header_t *icmp0, *icmp1;
 265
 266           /* Prefetch next iteration. */
 267           {
 268             vlib_buffer_t *p2, *p3;
 269
 270             p2 = vlib_get_buffer (vm, from[2]);
 271             p3 = vlib_get_buffer (vm, from[3]);
 272
 273             vlib_prefetch_buffer_header (p2, LOAD);
 274             vlib_prefetch_buffer_header (p3, LOAD);
 275
 276             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
 277             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
 278           }
 279
 280           /* speculatively enqueue b0 and b1 to the current next frame */
 281           to_next[0] = bi0 = from[0];
 282           to_next[1] = bi1 = from[1];
 283           from += 2;
 284           to_next += 2;
 285           n_left_from -= 2;
 286           n_left_to_next -= 2;
 287
 288           b0 = vlib_get_buffer (vm, bi0);
 289           b1 = vlib_get_buffer (vm, bi1);
 290
 291           ip0 = vlib_buffer_get_current (b0);
 292           udp0 = ip4_next_header (ip0);
 293           tcp0 = (tcp_header_t *) udp0;
 294
 295           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 296
 297           if (PREDICT_FALSE (ip0->ttl == 1))
 298             {
 299               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 300               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 301                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 302                                            0);
 303               next0 = NAT_DET_OUT2IN_NEXT_ICMP_ERROR;
 304               goto trace0;
 305             }
 306
 307           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 308
 309           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 310             {
 311               rx_fib_index0 =
 312                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 313               icmp0 = (icmp46_header_t *) udp0;
 314
 315               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
 316                                    rx_fib_index0, node, next0, thread_index,
 317                                    &ses0, &dm0);
 318               goto trace0;
 319             }
 320
 321           key0.ext_host_addr = ip0->src_address;
 322           key0.ext_host_port = tcp0->src;
 323           key0.out_port = tcp0->dst;
 324
 325           dm0 = snat_det_map_by_out (sm, &ip0->dst_address);
 326           if (PREDICT_FALSE (!dm0))
 327             {
 328               nat_log_info ("unknown dst address:  %U",
 329                             format_ip4_address, &ip0->dst_address);
 330               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 331               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 332               goto trace0;
 333             }
 334
 335           snat_det_reverse (dm0, &ip0->dst_address,
 336                             clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 337
 338           ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
 339           if (PREDICT_FALSE (!ses0))
 340             {
 341               nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 342                             format_ip4_address, &ip0->src_address,
 343                             clib_net_to_host_u16 (tcp0->src),
 344                             format_ip4_address, &ip0->dst_address,
 345                             clib_net_to_host_u16 (tcp0->dst),
 346                             format_ip4_address, &new_addr0);
 347               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 348               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 349               goto trace0;
 350             }
 351           old_port0 = udp0->dst_port;
 352           udp0->dst_port = new_port0 = ses0->in_port;
 353
 354           old_addr0 = ip0->dst_address;
 355           ip0->dst_address = new_addr0;
 356           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 357
 358           sum0 = ip0->checksum;
 359           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 360                                  ip4_header_t,
 361                                  dst_address /* changed member */ );
 362           ip0->checksum = ip_csum_fold (sum0);
 363
 364           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 365             {
 366               if (tcp0->flags & TCP_FLAG_FIN
 367                   && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 368                 ses0->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 369               else if (tcp0->flags & TCP_FLAG_ACK
 370                        && ses0->state == SNAT_SESSION_TCP_LAST_ACK)
 371                 snat_det_ses_close (dm0, ses0);
 372
 373               sum0 = tcp0->checksum;
 374               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 375                                      ip4_header_t,
 376                                      dst_address /* changed member */ );
 377               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 378                                      ip4_header_t /* cheat */ ,
 379                                      length /* changed member */ );
 380               tcp0->checksum = ip_csum_fold (sum0);
 381             }
 382           else if (udp0->checksum)
 383             {
 384               sum0 = udp0->checksum;
 385               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 386                                      ip4_header_t,
 387                                      dst_address /* changed member */ );
 388               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 389                                      ip4_header_t /* cheat */ ,
 390                                      length /* changed member */ );
 391               udp0->checksum = ip_csum_fold (sum0);
 392             }
 393
 394         trace0:
 395
 396           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 397                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 398             {
 399               nat_det_out2in_trace_t *t =
 400                 vlib_add_trace (vm, node, b0, sizeof (*t));
 401               t->sw_if_index = sw_if_index0;
 402               t->next_index = next0;
 403               t->session_index = ~0;
 404               if (ses0)
 405                 t->session_index = ses0 - dm0->sessions;
 406             }
 407
 408           pkts_processed += next0 != NAT_DET_OUT2IN_NEXT_DROP;
 409
 410           b1 = vlib_get_buffer (vm, bi1);
 411
 412           ip1 = vlib_buffer_get_current (b1);
 413           udp1 = ip4_next_header (ip1);
 414           tcp1 = (tcp_header_t *) udp1;
 415
 416           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 417
 418           if (PREDICT_FALSE (ip1->ttl == 1))
 419             {
 420               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 421               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 422                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 423                                            0);
 424               next1 = NAT_DET_OUT2IN_NEXT_ICMP_ERROR;
 425               goto trace1;
 426             }
 427
 428           proto1 = ip_proto_to_nat_proto (ip1->protocol);
 429
 430           if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 431             {
 432               rx_fib_index1 =
 433                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 434               icmp1 = (icmp46_header_t *) udp1;
 435
 436               next1 = icmp_out2in (sm, b1, ip1, icmp1, sw_if_index1,
 437                                    rx_fib_index1, node, next1, thread_index,
 438                                    &ses1, &dm1);
 439               goto trace1;
 440             }
 441
 442           key1.ext_host_addr = ip1->src_address;
 443           key1.ext_host_port = tcp1->src;
 444           key1.out_port = tcp1->dst;
 445
 446           dm1 = snat_det_map_by_out (sm, &ip1->dst_address);
 447           if (PREDICT_FALSE (!dm1))
 448             {
 449               nat_log_info ("unknown dst address:  %U",
 450                             format_ip4_address, &ip1->dst_address);
 451               next1 = NAT_DET_OUT2IN_NEXT_DROP;
 452               b1->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 453               goto trace1;
 454             }
 455
 456           snat_det_reverse (dm1, &ip1->dst_address,
 457                             clib_net_to_host_u16 (tcp1->dst), &new_addr1);
 458
 459           ses1 = snat_det_get_ses_by_out (dm1, &new_addr1, key1.as_u64);
 460           if (PREDICT_FALSE (!ses1))
 461             {
 462               nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 463                             format_ip4_address, &ip1->src_address,
 464                             clib_net_to_host_u16 (tcp1->src),
 465                             format_ip4_address, &ip1->dst_address,
 466                             clib_net_to_host_u16 (tcp1->dst),
 467                             format_ip4_address, &new_addr1);
 468               next1 = NAT_DET_OUT2IN_NEXT_DROP;
 469               b1->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 470               goto trace1;
 471             }
 472           old_port1 = udp1->dst_port;
 473           udp1->dst_port = new_port1 = ses1->in_port;
 474
 475           old_addr1 = ip1->dst_address;
 476           ip1->dst_address = new_addr1;
 477           vnet_buffer (b1)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 478
 479           sum1 = ip1->checksum;
 480           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 481                                  ip4_header_t,
 482                                  dst_address /* changed member */ );
 483           ip1->checksum = ip_csum_fold (sum1);
 484
 485           if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
 486             {
 487               if (tcp1->flags & TCP_FLAG_FIN
 488                   && ses1->state == SNAT_SESSION_TCP_ESTABLISHED)
 489                 ses1->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 490               else if (tcp1->flags & TCP_FLAG_ACK
 491                        && ses1->state == SNAT_SESSION_TCP_LAST_ACK)
 492                 snat_det_ses_close (dm1, ses1);
 493
 494               sum1 = tcp1->checksum;
 495               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 496                                      ip4_header_t,
 497                                      dst_address /* changed member */ );
 498               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 499                                      ip4_header_t /* cheat */ ,
 500                                      length /* changed member */ );
 501               tcp1->checksum = ip_csum_fold (sum1);
 502             }
 503           else if (udp1->checksum)
 504             {
 505               sum1 = udp1->checksum;
 506               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 507                                      ip4_header_t,
 508                                      dst_address /* changed member */ );
 509               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 510                                      ip4_header_t /* cheat */ ,
 511                                      length /* changed member */ );
 512               udp1->checksum = ip_csum_fold (sum1);
 513             }
 514
 515         trace1:
 516
 517           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 518                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 519             {
 520               nat_det_out2in_trace_t *t =
 521                 vlib_add_trace (vm, node, b1, sizeof (*t));
 522               t->sw_if_index = sw_if_index1;
 523               t->next_index = next1;
 524               t->session_index = ~0;
 525               if (ses1)
 526                 t->session_index = ses1 - dm1->sessions;
 527             }
 528
 529           pkts_processed += next1 != NAT_DET_OUT2IN_NEXT_DROP;
 530
 531           /* verify speculative enqueues, maybe switch current next frame */
 532           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 533                                            to_next, n_left_to_next,
 534                                            bi0, bi1, next0, next1);
 535         }
 536
 537       while (n_left_from > 0 && n_left_to_next > 0)
 538         {
 539           u32 bi0;
 540           vlib_buffer_t *b0;
 541           u32 next0 = NAT_DET_OUT2IN_NEXT_LOOKUP;
 542           u32 sw_if_index0;
 543           ip4_header_t *ip0;
 544           ip_csum_t sum0;
 545           ip4_address_t new_addr0, old_addr0;
 546           u16 new_port0, old_port0;
 547           udp_header_t *udp0;
 548           tcp_header_t *tcp0;
 549           u32 proto0;
 550           snat_det_out_key_t key0;
 551           snat_det_map_t *dm0;
 552           snat_det_session_t *ses0 = 0;
 553           u32 rx_fib_index0;
 554           icmp46_header_t *icmp0;
 555
 556           /* speculatively enqueue b0 to the current next frame */
 557           bi0 = from[0];
 558           to_next[0] = bi0;
 559           from += 1;
 560           to_next += 1;
 561           n_left_from -= 1;
 562           n_left_to_next -= 1;
 563
 564           b0 = vlib_get_buffer (vm, bi0);
 565
 566           ip0 = vlib_buffer_get_current (b0);
 567           udp0 = ip4_next_header (ip0);
 568           tcp0 = (tcp_header_t *) udp0;
 569
 570           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 571
 572           if (PREDICT_FALSE (ip0->ttl == 1))
 573             {
 574               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 575               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 576                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 577                                            0);
 578               next0 = NAT_DET_OUT2IN_NEXT_ICMP_ERROR;
 579               goto trace00;
 580             }
 581
 582           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 583
 584           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 585             {
 586               rx_fib_index0 =
 587                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 588               icmp0 = (icmp46_header_t *) udp0;
 589
 590               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
 591                                    rx_fib_index0, node, next0, thread_index,
 592                                    &ses0, &dm0);
 593               goto trace00;
 594             }
 595
 596           key0.ext_host_addr = ip0->src_address;
 597           key0.ext_host_port = tcp0->src;
 598           key0.out_port = tcp0->dst;
 599
 600           dm0 = snat_det_map_by_out (sm, &ip0->dst_address);
 601           if (PREDICT_FALSE (!dm0))
 602             {
 603               nat_log_info ("unknown dst address:  %U",
 604                             format_ip4_address, &ip0->dst_address);
 605               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 606               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 607               goto trace00;
 608             }
 609
 610           snat_det_reverse (dm0, &ip0->dst_address,
 611                             clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 612
 613           ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
 614           if (PREDICT_FALSE (!ses0))
 615             {
 616               nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 617                             format_ip4_address, &ip0->src_address,
 618                             clib_net_to_host_u16 (tcp0->src),
 619                             format_ip4_address, &ip0->dst_address,
 620                             clib_net_to_host_u16 (tcp0->dst),
 621                             format_ip4_address, &new_addr0);
 622               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 623               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 624               goto trace00;
 625             }
 626           old_port0 = udp0->dst_port;
 627           udp0->dst_port = new_port0 = ses0->in_port;
 628
 629           old_addr0 = ip0->dst_address;
 630           ip0->dst_address = new_addr0;
 631           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 632
 633           sum0 = ip0->checksum;
 634           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 635                                  ip4_header_t,
 636                                  dst_address /* changed member */ );
 637           ip0->checksum = ip_csum_fold (sum0);
 638
 639           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 640             {
 641               if (tcp0->flags & TCP_FLAG_FIN
 642                   && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 643                 ses0->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 644               else if (tcp0->flags & TCP_FLAG_ACK
 645                        && ses0->state == SNAT_SESSION_TCP_LAST_ACK)
 646                 snat_det_ses_close (dm0, ses0);
 647
 648               sum0 = tcp0->checksum;
 649               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 650                                      ip4_header_t,
 651                                      dst_address /* changed member */ );
 652               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 653                                      ip4_header_t /* cheat */ ,
 654                                      length /* changed member */ );
 655               tcp0->checksum = ip_csum_fold (sum0);
 656             }
 657           else if (udp0->checksum)
 658             {
 659               sum0 = udp0->checksum;
 660               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 661                                      ip4_header_t,
 662                                      dst_address /* changed member */ );
 663               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 664                                      ip4_header_t /* cheat */ ,
 665                                      length /* changed member */ );
 666               udp0->checksum = ip_csum_fold (sum0);
 667             }
 668
 669         trace00:
 670
 671           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 672                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 673             {
 674               nat_det_out2in_trace_t *t =
 675                 vlib_add_trace (vm, node, b0, sizeof (*t));
 676               t->sw_if_index = sw_if_index0;
 677               t->next_index = next0;
 678               t->session_index = ~0;
 679               if (ses0)
 680                 t->session_index = ses0 - dm0->sessions;
 681             }
 682
 683           pkts_processed += next0 != NAT_DET_OUT2IN_NEXT_DROP;
 684
 685           /* verify speculative enqueue, maybe switch current next frame */
 686           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 687                                            to_next, n_left_to_next,
 688                                            bi0, next0);
 689         }
 690
 691       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 692     }
 693
 694   vlib_node_increment_counter (vm, sm->det_out2in_node_index,
 695                                NAT_DET_OUT2IN_ERROR_OUT2IN_PACKETS,
 696                                pkts_processed);
 697   return frame->n_vectors;
 698 }
 699
 700 /* *INDENT-OFF* */
 701 VLIB_REGISTER_NODE (snat_det_out2in_node) = {
 702   .name = "nat44-det-out2in",
 703   .vector_size = sizeof (u32),
 704   .format_trace = format_nat_det_out2in_trace,
 705   .type = VLIB_NODE_TYPE_INTERNAL,
 706   .n_errors = ARRAY_LEN(nat_det_out2in_error_strings),
 707   .error_strings = nat_det_out2in_error_strings,
 708   .runtime_data_bytes = sizeof (snat_runtime_t),
 709   .n_next_nodes = NAT_DET_OUT2IN_N_NEXT,
 710   /* edit / add dispositions here */
 711   .next_nodes = {
 712     [NAT_DET_OUT2IN_NEXT_DROP] = "error-drop",
 713     [NAT_DET_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
 714     [NAT_DET_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 715   },
 716 };
 717 /* *INDENT-ON* */
 718
 719 /*
 720  * fd.io coding-style-patch-verification: ON
 721  *
 722  * Local Variables:
 723  * eval: (c-set-style "gnu")
 724  * End:
 725  */