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 vlib_node_registration_t snat_det_out2in_node;
  66
  67 static u8 *
  68 format_nat_det_out2in_trace (u8 * s, va_list * args)
  69 {
  70   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  71   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  72   nat_det_out2in_trace_t *t = va_arg (*args, nat_det_out2in_trace_t *);
  73
  74   s =
  75     format (s,
  76             "NAT_DET_OUT2IN: sw_if_index %d, next index %d, session index %d",
  77             t->sw_if_index, t->next_index, t->session_index);
  78   return s;
  79 }
  80
  81 /**
  82  * Get address and port values to be used for ICMP packet translation
  83  * and create session if needed
  84  *
  85  * @param[in,out] sm             NAT main
  86  * @param[in,out] node           NAT node runtime
  87  * @param[in] thread_index       thread index
  88  * @param[in,out] b0             buffer containing packet to be translated
  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, u8 * p_proto,
  99                        snat_session_key_t * p_value,
 100                        u8 * p_dont_translate, void *d, void *e)
 101 {
 102   icmp46_header_t *icmp0;
 103   u32 sw_if_index0;
 104   u8 protocol;
 105   snat_det_out_key_t key0;
 106   u8 dont_translate = 0;
 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
 117   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 118   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 119   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 120
 121   if (!icmp_is_error_message (icmp0))
 122     {
 123       protocol = SNAT_PROTOCOL_ICMP;
 124       key0.ext_host_addr = ip0->src_address;
 125       key0.ext_host_port = 0;
 126       key0.out_port = echo0->identifier;
 127       out_addr = ip0->dst_address;
 128     }
 129   else
 130     {
 131       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 132       l4_header = ip4_next_header (inner_ip0);
 133       protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 134       key0.ext_host_addr = inner_ip0->dst_address;
 135       out_addr = inner_ip0->src_address;
 136       switch (protocol)
 137         {
 138         case SNAT_PROTOCOL_ICMP:
 139           inner_icmp0 = (icmp46_header_t *) l4_header;
 140           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 141           key0.ext_host_port = 0;
 142           key0.out_port = inner_echo0->identifier;
 143           break;
 144         case SNAT_PROTOCOL_UDP:
 145         case SNAT_PROTOCOL_TCP:
 146           key0.ext_host_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 147           key0.out_port = ((tcp_udp_header_t *) l4_header)->src_port;
 148           break;
 149         default:
 150           b0->error = node->errors[NAT_DET_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 151           next0 = NAT_DET_OUT2IN_NEXT_DROP;
 152           goto out;
 153         }
 154     }
 155
 156   dm0 = snat_det_map_by_out (sm, &out_addr);
 157   if (PREDICT_FALSE (!dm0))
 158     {
 159       /* Don't NAT packet aimed at the intfc address */
 160       if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 161                                             ip0->dst_address.as_u32)))
 162         {
 163           dont_translate = 1;
 164           goto out;
 165         }
 166       nat_log_info ("unknown dst address:  %U",
 167                     format_ip4_address, &ip0->dst_address);
 168       goto out;
 169     }
 170
 171   snat_det_reverse (dm0, &ip0->dst_address,
 172                     clib_net_to_host_u16 (key0.out_port), &new_addr0);
 173
 174   ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
 175   if (PREDICT_FALSE (!ses0))
 176     {
 177       /* Don't NAT packet aimed at the intfc address */
 178       if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 179                                             ip0->dst_address.as_u32)))
 180         {
 181           dont_translate = 1;
 182           goto out;
 183         }
 184       nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 185                     format_ip4_address, &key0.ext_host_addr,
 186                     clib_net_to_host_u16 (key0.ext_host_port),
 187                     format_ip4_address, &out_addr,
 188                     clib_net_to_host_u16 (key0.out_port),
 189                     format_ip4_address, &new_addr0);
 190       b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 191       next0 = NAT_DET_OUT2IN_NEXT_DROP;
 192       goto out;
 193     }
 194
 195   if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
 196                      !icmp_is_error_message (icmp0)))
 197     {
 198       b0->error = node->errors[NAT_DET_OUT2IN_ERROR_BAD_ICMP_TYPE];
 199       next0 = NAT_DET_OUT2IN_NEXT_DROP;
 200       goto out;
 201     }
 202
 203   goto out;
 204
 205 out:
 206   *p_proto = protocol;
 207   if (ses0)
 208     {
 209       p_value->addr = new_addr0;
 210       p_value->fib_index = sm->inside_fib_index;
 211       p_value->port = ses0->in_port;
 212     }
 213   *p_dont_translate = dont_translate;
 214   if (d)
 215     *(snat_det_session_t **) d = ses0;
 216   if (e)
 217     *(snat_det_map_t **) e = dm0;
 218   return next0;
 219 }
 220
 221 static uword
 222 snat_det_out2in_node_fn (vlib_main_t * vm,
 223                          vlib_node_runtime_t * node, vlib_frame_t * frame)
 224 {
 225   u32 n_left_from, *from, *to_next;
 226   nat_det_out2in_next_t next_index;
 227   u32 pkts_processed = 0;
 228   snat_main_t *sm = &snat_main;
 229   u32 thread_index = vm->thread_index;
 230
 231   from = vlib_frame_vector_args (frame);
 232   n_left_from = frame->n_vectors;
 233   next_index = node->cached_next_index;
 234
 235   while (n_left_from > 0)
 236     {
 237       u32 n_left_to_next;
 238
 239       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 240
 241       while (n_left_from >= 4 && n_left_to_next >= 2)
 242         {
 243           u32 bi0, bi1;
 244           vlib_buffer_t *b0, *b1;
 245           u32 next0 = NAT_DET_OUT2IN_NEXT_LOOKUP;
 246           u32 next1 = NAT_DET_OUT2IN_NEXT_LOOKUP;
 247           u32 sw_if_index0, sw_if_index1;
 248           ip4_header_t *ip0, *ip1;
 249           ip_csum_t sum0, sum1;
 250           ip4_address_t new_addr0, old_addr0, new_addr1, old_addr1;
 251           u16 new_port0, old_port0, old_port1, new_port1;
 252           udp_header_t *udp0, *udp1;
 253           tcp_header_t *tcp0, *tcp1;
 254           u32 proto0, proto1;
 255           snat_det_out_key_t key0, key1;
 256           snat_det_map_t *dm0, *dm1;
 257           snat_det_session_t *ses0 = 0, *ses1 = 0;
 258           u32 rx_fib_index0, rx_fib_index1;
 259           icmp46_header_t *icmp0, *icmp1;
 260
 261           /* Prefetch next iteration. */
 262           {
 263             vlib_buffer_t *p2, *p3;
 264
 265             p2 = vlib_get_buffer (vm, from[2]);
 266             p3 = vlib_get_buffer (vm, from[3]);
 267
 268             vlib_prefetch_buffer_header (p2, LOAD);
 269             vlib_prefetch_buffer_header (p3, LOAD);
 270
 271             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 272             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 273           }
 274
 275           /* speculatively enqueue b0 and b1 to the current next frame */
 276           to_next[0] = bi0 = from[0];
 277           to_next[1] = bi1 = from[1];
 278           from += 2;
 279           to_next += 2;
 280           n_left_from -= 2;
 281           n_left_to_next -= 2;
 282
 283           b0 = vlib_get_buffer (vm, bi0);
 284           b1 = vlib_get_buffer (vm, bi1);
 285
 286           ip0 = vlib_buffer_get_current (b0);
 287           udp0 = ip4_next_header (ip0);
 288           tcp0 = (tcp_header_t *) udp0;
 289
 290           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 291
 292           if (PREDICT_FALSE (ip0->ttl == 1))
 293             {
 294               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 295               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 296                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 297                                            0);
 298               next0 = NAT_DET_OUT2IN_NEXT_ICMP_ERROR;
 299               goto trace0;
 300             }
 301
 302           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 303
 304           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 305             {
 306               rx_fib_index0 =
 307                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 308               icmp0 = (icmp46_header_t *) udp0;
 309
 310               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
 311                                    rx_fib_index0, node, next0, thread_index,
 312                                    &ses0, &dm0);
 313               goto trace0;
 314             }
 315
 316           key0.ext_host_addr = ip0->src_address;
 317           key0.ext_host_port = tcp0->src;
 318           key0.out_port = tcp0->dst;
 319
 320           dm0 = snat_det_map_by_out (sm, &ip0->dst_address);
 321           if (PREDICT_FALSE (!dm0))
 322             {
 323               nat_log_info ("unknown dst address:  %U",
 324                             format_ip4_address, &ip0->dst_address);
 325               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 326               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 327               goto trace0;
 328             }
 329
 330           snat_det_reverse (dm0, &ip0->dst_address,
 331                             clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 332
 333           ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
 334           if (PREDICT_FALSE (!ses0))
 335             {
 336               nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 337                             format_ip4_address, &ip0->src_address,
 338                             clib_net_to_host_u16 (tcp0->src),
 339                             format_ip4_address, &ip0->dst_address,
 340                             clib_net_to_host_u16 (tcp0->dst),
 341                             format_ip4_address, &new_addr0);
 342               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 343               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 344               goto trace0;
 345             }
 346           new_port0 = ses0->in_port;
 347
 348           old_addr0 = ip0->dst_address;
 349           ip0->dst_address = new_addr0;
 350           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 351
 352           sum0 = ip0->checksum;
 353           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 354                                  ip4_header_t,
 355                                  dst_address /* changed member */ );
 356           ip0->checksum = ip_csum_fold (sum0);
 357
 358           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 359             {
 360               if (tcp0->flags & TCP_FLAG_FIN
 361                   && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 362                 ses0->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 363               else if (tcp0->flags & TCP_FLAG_ACK
 364                        && ses0->state == SNAT_SESSION_TCP_LAST_ACK)
 365                 snat_det_ses_close (dm0, ses0);
 366
 367               old_port0 = tcp0->dst;
 368               tcp0->dst = new_port0;
 369
 370               sum0 = tcp0->checksum;
 371               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 372                                      ip4_header_t,
 373                                      dst_address /* changed member */ );
 374
 375               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 376                                      ip4_header_t /* cheat */ ,
 377                                      length /* changed member */ );
 378               tcp0->checksum = ip_csum_fold (sum0);
 379             }
 380           else
 381             {
 382               old_port0 = udp0->dst_port;
 383               udp0->dst_port = new_port0;
 384               udp0->checksum = 0;
 385             }
 386
 387         trace0:
 388
 389           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 390                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 391             {
 392               nat_det_out2in_trace_t *t =
 393                 vlib_add_trace (vm, node, b0, sizeof (*t));
 394               t->sw_if_index = sw_if_index0;
 395               t->next_index = next0;
 396               t->session_index = ~0;
 397               if (ses0)
 398                 t->session_index = ses0 - dm0->sessions;
 399             }
 400
 401           pkts_processed += next0 != NAT_DET_OUT2IN_NEXT_DROP;
 402
 403           b1 = vlib_get_buffer (vm, bi1);
 404
 405           ip1 = vlib_buffer_get_current (b1);
 406           udp1 = ip4_next_header (ip1);
 407           tcp1 = (tcp_header_t *) udp1;
 408
 409           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 410
 411           if (PREDICT_FALSE (ip1->ttl == 1))
 412             {
 413               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 414               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 415                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 416                                            0);
 417               next1 = NAT_DET_OUT2IN_NEXT_ICMP_ERROR;
 418               goto trace1;
 419             }
 420
 421           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 422
 423           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
 424             {
 425               rx_fib_index1 =
 426                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 427               icmp1 = (icmp46_header_t *) udp1;
 428
 429               next1 = icmp_out2in (sm, b1, ip1, icmp1, sw_if_index1,
 430                                    rx_fib_index1, node, next1, thread_index,
 431                                    &ses1, &dm1);
 432               goto trace1;
 433             }
 434
 435           key1.ext_host_addr = ip1->src_address;
 436           key1.ext_host_port = tcp1->src;
 437           key1.out_port = tcp1->dst;
 438
 439           dm1 = snat_det_map_by_out (sm, &ip1->dst_address);
 440           if (PREDICT_FALSE (!dm1))
 441             {
 442               nat_log_info ("unknown dst address:  %U",
 443                             format_ip4_address, &ip1->dst_address);
 444               next1 = NAT_DET_OUT2IN_NEXT_DROP;
 445               b1->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 446               goto trace1;
 447             }
 448
 449           snat_det_reverse (dm1, &ip1->dst_address,
 450                             clib_net_to_host_u16 (tcp1->dst), &new_addr1);
 451
 452           ses1 = snat_det_get_ses_by_out (dm1, &new_addr1, key1.as_u64);
 453           if (PREDICT_FALSE (!ses1))
 454             {
 455               nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 456                             format_ip4_address, &ip1->src_address,
 457                             clib_net_to_host_u16 (tcp1->src),
 458                             format_ip4_address, &ip1->dst_address,
 459                             clib_net_to_host_u16 (tcp1->dst),
 460                             format_ip4_address, &new_addr1);
 461               next1 = NAT_DET_OUT2IN_NEXT_DROP;
 462               b1->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 463               goto trace1;
 464             }
 465           new_port1 = ses1->in_port;
 466
 467           old_addr1 = ip1->dst_address;
 468           ip1->dst_address = new_addr1;
 469           vnet_buffer (b1)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 470
 471           sum1 = ip1->checksum;
 472           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 473                                  ip4_header_t,
 474                                  dst_address /* changed member */ );
 475           ip1->checksum = ip_csum_fold (sum1);
 476
 477           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
 478             {
 479               if (tcp1->flags & TCP_FLAG_FIN
 480                   && ses1->state == SNAT_SESSION_TCP_ESTABLISHED)
 481                 ses1->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 482               else if (tcp1->flags & TCP_FLAG_ACK
 483                        && ses1->state == SNAT_SESSION_TCP_LAST_ACK)
 484                 snat_det_ses_close (dm1, ses1);
 485
 486               old_port1 = tcp1->dst;
 487               tcp1->dst = new_port1;
 488
 489               sum1 = tcp1->checksum;
 490               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 491                                      ip4_header_t,
 492                                      dst_address /* changed member */ );
 493
 494               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 495                                      ip4_header_t /* cheat */ ,
 496                                      length /* changed member */ );
 497               tcp1->checksum = ip_csum_fold (sum1);
 498             }
 499           else
 500             {
 501               old_port1 = udp1->dst_port;
 502               udp1->dst_port = new_port1;
 503               udp1->checksum = 0;
 504             }
 505
 506         trace1:
 507
 508           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 509                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 510             {
 511               nat_det_out2in_trace_t *t =
 512                 vlib_add_trace (vm, node, b1, sizeof (*t));
 513               t->sw_if_index = sw_if_index1;
 514               t->next_index = next1;
 515               t->session_index = ~0;
 516               if (ses1)
 517                 t->session_index = ses1 - dm1->sessions;
 518             }
 519
 520           pkts_processed += next1 != NAT_DET_OUT2IN_NEXT_DROP;
 521
 522           /* verify speculative enqueues, maybe switch current next frame */
 523           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 524                                            to_next, n_left_to_next,
 525                                            bi0, bi1, next0, next1);
 526         }
 527
 528       while (n_left_from > 0 && n_left_to_next > 0)
 529         {
 530           u32 bi0;
 531           vlib_buffer_t *b0;
 532           u32 next0 = NAT_DET_OUT2IN_NEXT_LOOKUP;
 533           u32 sw_if_index0;
 534           ip4_header_t *ip0;
 535           ip_csum_t sum0;
 536           ip4_address_t new_addr0, old_addr0;
 537           u16 new_port0, old_port0;
 538           udp_header_t *udp0;
 539           tcp_header_t *tcp0;
 540           u32 proto0;
 541           snat_det_out_key_t key0;
 542           snat_det_map_t *dm0;
 543           snat_det_session_t *ses0 = 0;
 544           u32 rx_fib_index0;
 545           icmp46_header_t *icmp0;
 546
 547           /* speculatively enqueue b0 to the current next frame */
 548           bi0 = from[0];
 549           to_next[0] = bi0;
 550           from += 1;
 551           to_next += 1;
 552           n_left_from -= 1;
 553           n_left_to_next -= 1;
 554
 555           b0 = vlib_get_buffer (vm, bi0);
 556
 557           ip0 = vlib_buffer_get_current (b0);
 558           udp0 = ip4_next_header (ip0);
 559           tcp0 = (tcp_header_t *) udp0;
 560
 561           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 562
 563           if (PREDICT_FALSE (ip0->ttl == 1))
 564             {
 565               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 566               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 567                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 568                                            0);
 569               next0 = NAT_DET_OUT2IN_NEXT_ICMP_ERROR;
 570               goto trace00;
 571             }
 572
 573           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 574
 575           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 576             {
 577               rx_fib_index0 =
 578                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 579               icmp0 = (icmp46_header_t *) udp0;
 580
 581               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
 582                                    rx_fib_index0, node, next0, thread_index,
 583                                    &ses0, &dm0);
 584               goto trace00;
 585             }
 586
 587           key0.ext_host_addr = ip0->src_address;
 588           key0.ext_host_port = tcp0->src;
 589           key0.out_port = tcp0->dst;
 590
 591           dm0 = snat_det_map_by_out (sm, &ip0->dst_address);
 592           if (PREDICT_FALSE (!dm0))
 593             {
 594               nat_log_info ("unknown dst address:  %U",
 595                             format_ip4_address, &ip0->dst_address);
 596               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 597               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 598               goto trace00;
 599             }
 600
 601           snat_det_reverse (dm0, &ip0->dst_address,
 602                             clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 603
 604           ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
 605           if (PREDICT_FALSE (!ses0))
 606             {
 607               nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 608                             format_ip4_address, &ip0->src_address,
 609                             clib_net_to_host_u16 (tcp0->src),
 610                             format_ip4_address, &ip0->dst_address,
 611                             clib_net_to_host_u16 (tcp0->dst),
 612                             format_ip4_address, &new_addr0);
 613               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 614               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 615               goto trace00;
 616             }
 617           new_port0 = ses0->in_port;
 618
 619           old_addr0 = ip0->dst_address;
 620           ip0->dst_address = new_addr0;
 621           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 622
 623           sum0 = ip0->checksum;
 624           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 625                                  ip4_header_t,
 626                                  dst_address /* changed member */ );
 627           ip0->checksum = ip_csum_fold (sum0);
 628
 629           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 630             {
 631               if (tcp0->flags & TCP_FLAG_FIN
 632                   && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 633                 ses0->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 634               else if (tcp0->flags & TCP_FLAG_ACK
 635                        && ses0->state == SNAT_SESSION_TCP_LAST_ACK)
 636                 snat_det_ses_close (dm0, ses0);
 637
 638               old_port0 = tcp0->dst;
 639               tcp0->dst = new_port0;
 640
 641               sum0 = tcp0->checksum;
 642               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 643                                      ip4_header_t,
 644                                      dst_address /* changed member */ );
 645
 646               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 647                                      ip4_header_t /* cheat */ ,
 648                                      length /* changed member */ );
 649               tcp0->checksum = ip_csum_fold (sum0);
 650             }
 651           else
 652             {
 653               old_port0 = udp0->dst_port;
 654               udp0->dst_port = new_port0;
 655               udp0->checksum = 0;
 656             }
 657
 658         trace00:
 659
 660           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 661                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 662             {
 663               nat_det_out2in_trace_t *t =
 664                 vlib_add_trace (vm, node, b0, sizeof (*t));
 665               t->sw_if_index = sw_if_index0;
 666               t->next_index = next0;
 667               t->session_index = ~0;
 668               if (ses0)
 669                 t->session_index = ses0 - dm0->sessions;
 670             }
 671
 672           pkts_processed += next0 != NAT_DET_OUT2IN_NEXT_DROP;
 673
 674           /* verify speculative enqueue, maybe switch current next frame */
 675           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 676                                            to_next, n_left_to_next,
 677                                            bi0, next0);
 678         }
 679
 680       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 681     }
 682
 683   vlib_node_increment_counter (vm, snat_det_out2in_node.index,
 684                                NAT_DET_OUT2IN_ERROR_OUT2IN_PACKETS,
 685                                pkts_processed);
 686   return frame->n_vectors;
 687 }
 688
 689 /* *INDENT-OFF* */
 690 VLIB_REGISTER_NODE (snat_det_out2in_node) = {
 691   .function = snat_det_out2in_node_fn,
 692   .name = "nat44-det-out2in",
 693   .vector_size = sizeof (u32),
 694   .format_trace = format_nat_det_out2in_trace,
 695   .type = VLIB_NODE_TYPE_INTERNAL,
 696   .n_errors = ARRAY_LEN(nat_det_out2in_error_strings),
 697   .error_strings = nat_det_out2in_error_strings,
 698   .runtime_data_bytes = sizeof (snat_runtime_t),
 699   .n_next_nodes = NAT_DET_OUT2IN_N_NEXT,
 700   /* edit / add dispositions here */
 701   .next_nodes = {
 702     [NAT_DET_OUT2IN_NEXT_DROP] = "error-drop",
 703     [NAT_DET_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
 704     [NAT_DET_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 705   },
 706 };
 707 /* *INDENT-ON* */
 708
 709 VLIB_NODE_FUNCTION_MULTIARCH (snat_det_out2in_node, snat_det_out2in_node_fn);
 710
 711 /*
 712  * fd.io coding-style-patch-verification: ON
 713  *
 714  * Local Variables:
 715  * eval: (c-set-style "gnu")
 716  * End:
 717  */