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[out] p_proto           protocol used for matching
  89  * @param[out] p_value           address and port after NAT translation
  90  * @param[out] p_dont_translate  if packet should not be translated
  91  * @param d                      optional parameter
  92  * @param e                      optional parameter
  93  */
  94 u32
  95 icmp_match_out2in_det (snat_main_t * sm, vlib_node_runtime_t * node,
  96                        u32 thread_index, vlib_buffer_t * b0,
  97                        ip4_header_t * ip0, u8 * p_proto,
  98                        snat_session_key_t * p_value,
  99                        u8 * p_dont_translate, void *d, void *e)
 100 {
 101   icmp46_header_t *icmp0;
 102   u32 sw_if_index0;
 103   u8 protocol;
 104   snat_det_out_key_t key0;
 105   u8 dont_translate = 0;
 106   u32 next0 = ~0;
 107   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 108   ip4_header_t *inner_ip0;
 109   void *l4_header = 0;
 110   icmp46_header_t *inner_icmp0;
 111   snat_det_map_t *dm0 = 0;
 112   ip4_address_t new_addr0 = { {0} };
 113   snat_det_session_t *ses0 = 0;
 114   ip4_address_t out_addr;
 115
 116   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 117   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 118   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 119
 120   if (!icmp_is_error_message (icmp0))
 121     {
 122       protocol = SNAT_PROTOCOL_ICMP;
 123       key0.ext_host_addr = ip0->src_address;
 124       key0.ext_host_port = 0;
 125       key0.out_port = echo0->identifier;
 126       out_addr = ip0->dst_address;
 127     }
 128   else
 129     {
 130       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 131       l4_header = ip4_next_header (inner_ip0);
 132       protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 133       key0.ext_host_addr = inner_ip0->dst_address;
 134       out_addr = inner_ip0->src_address;
 135       switch (protocol)
 136         {
 137         case SNAT_PROTOCOL_ICMP:
 138           inner_icmp0 = (icmp46_header_t *) l4_header;
 139           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 140           key0.ext_host_port = 0;
 141           key0.out_port = inner_echo0->identifier;
 142           break;
 143         case SNAT_PROTOCOL_UDP:
 144         case SNAT_PROTOCOL_TCP:
 145           key0.ext_host_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 146           key0.out_port = ((tcp_udp_header_t *) l4_header)->src_port;
 147           break;
 148         default:
 149           b0->error = node->errors[NAT_DET_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 150           next0 = NAT_DET_OUT2IN_NEXT_DROP;
 151           goto out;
 152         }
 153     }
 154
 155   dm0 = snat_det_map_by_out (sm, &out_addr);
 156   if (PREDICT_FALSE (!dm0))
 157     {
 158       /* Don't NAT packet aimed at the intfc address */
 159       if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 160                                             ip0->dst_address.as_u32)))
 161         {
 162           dont_translate = 1;
 163           goto out;
 164         }
 165       nat_log_info ("unknown dst address:  %U",
 166                     format_ip4_address, &ip0->dst_address);
 167       goto out;
 168     }
 169
 170   snat_det_reverse (dm0, &ip0->dst_address,
 171                     clib_net_to_host_u16 (key0.out_port), &new_addr0);
 172
 173   ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
 174   if (PREDICT_FALSE (!ses0))
 175     {
 176       /* Don't NAT packet aimed at the intfc address */
 177       if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 178                                             ip0->dst_address.as_u32)))
 179         {
 180           dont_translate = 1;
 181           goto out;
 182         }
 183       nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 184                     format_ip4_address, &key0.ext_host_addr,
 185                     clib_net_to_host_u16 (key0.ext_host_port),
 186                     format_ip4_address, &out_addr,
 187                     clib_net_to_host_u16 (key0.out_port),
 188                     format_ip4_address, &new_addr0);
 189       b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 190       next0 = NAT_DET_OUT2IN_NEXT_DROP;
 191       goto out;
 192     }
 193
 194   if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
 195                      !icmp_is_error_message (icmp0)))
 196     {
 197       b0->error = node->errors[NAT_DET_OUT2IN_ERROR_BAD_ICMP_TYPE];
 198       next0 = NAT_DET_OUT2IN_NEXT_DROP;
 199       goto out;
 200     }
 201
 202   goto out;
 203
 204 out:
 205   *p_proto = protocol;
 206   if (ses0)
 207     {
 208       p_value->addr = new_addr0;
 209       p_value->fib_index = sm->inside_fib_index;
 210       p_value->port = ses0->in_port;
 211     }
 212   *p_dont_translate = dont_translate;
 213   if (d)
 214     *(snat_det_session_t **) d = ses0;
 215   if (e)
 216     *(snat_det_map_t **) e = dm0;
 217   return next0;
 218 }
 219 #endif
 220
 221 VLIB_NODE_FN (snat_det_out2in_node) (vlib_main_t * vm,
 222                                      vlib_node_runtime_t * node,
 223                                      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           old_port0 = udp0->dst_port;
 347           udp0->dst_port = new_port0 = ses0->in_port;
 348
 349           old_addr0 = ip0->dst_address;
 350           ip0->dst_address = new_addr0;
 351           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 352
 353           sum0 = ip0->checksum;
 354           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 355                                  ip4_header_t,
 356                                  dst_address /* changed member */ );
 357           ip0->checksum = ip_csum_fold (sum0);
 358
 359           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 360             {
 361               if (tcp0->flags & TCP_FLAG_FIN
 362                   && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 363                 ses0->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 364               else if (tcp0->flags & TCP_FLAG_ACK
 365                        && ses0->state == SNAT_SESSION_TCP_LAST_ACK)
 366                 snat_det_ses_close (dm0, ses0);
 367
 368               sum0 = tcp0->checksum;
 369               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 370                                      ip4_header_t,
 371                                      dst_address /* changed member */ );
 372               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 373                                      ip4_header_t /* cheat */ ,
 374                                      length /* changed member */ );
 375               tcp0->checksum = ip_csum_fold (sum0);
 376             }
 377           else if (udp0->checksum)
 378             {
 379               sum0 = udp0->checksum;
 380               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 381                                      ip4_header_t,
 382                                      dst_address /* changed member */ );
 383               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 384                                      ip4_header_t /* cheat */ ,
 385                                      length /* changed member */ );
 386               udp0->checksum = ip_csum_fold (sum0);
 387             }
 388
 389         trace0:
 390
 391           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 392                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 393             {
 394               nat_det_out2in_trace_t *t =
 395                 vlib_add_trace (vm, node, b0, sizeof (*t));
 396               t->sw_if_index = sw_if_index0;
 397               t->next_index = next0;
 398               t->session_index = ~0;
 399               if (ses0)
 400                 t->session_index = ses0 - dm0->sessions;
 401             }
 402
 403           pkts_processed += next0 != NAT_DET_OUT2IN_NEXT_DROP;
 404
 405           b1 = vlib_get_buffer (vm, bi1);
 406
 407           ip1 = vlib_buffer_get_current (b1);
 408           udp1 = ip4_next_header (ip1);
 409           tcp1 = (tcp_header_t *) udp1;
 410
 411           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 412
 413           if (PREDICT_FALSE (ip1->ttl == 1))
 414             {
 415               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 416               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 417                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 418                                            0);
 419               next1 = NAT_DET_OUT2IN_NEXT_ICMP_ERROR;
 420               goto trace1;
 421             }
 422
 423           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 424
 425           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
 426             {
 427               rx_fib_index1 =
 428                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 429               icmp1 = (icmp46_header_t *) udp1;
 430
 431               next1 = icmp_out2in (sm, b1, ip1, icmp1, sw_if_index1,
 432                                    rx_fib_index1, node, next1, thread_index,
 433                                    &ses1, &dm1);
 434               goto trace1;
 435             }
 436
 437           key1.ext_host_addr = ip1->src_address;
 438           key1.ext_host_port = tcp1->src;
 439           key1.out_port = tcp1->dst;
 440
 441           dm1 = snat_det_map_by_out (sm, &ip1->dst_address);
 442           if (PREDICT_FALSE (!dm1))
 443             {
 444               nat_log_info ("unknown dst address:  %U",
 445                             format_ip4_address, &ip1->dst_address);
 446               next1 = NAT_DET_OUT2IN_NEXT_DROP;
 447               b1->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 448               goto trace1;
 449             }
 450
 451           snat_det_reverse (dm1, &ip1->dst_address,
 452                             clib_net_to_host_u16 (tcp1->dst), &new_addr1);
 453
 454           ses1 = snat_det_get_ses_by_out (dm1, &new_addr1, key1.as_u64);
 455           if (PREDICT_FALSE (!ses1))
 456             {
 457               nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 458                             format_ip4_address, &ip1->src_address,
 459                             clib_net_to_host_u16 (tcp1->src),
 460                             format_ip4_address, &ip1->dst_address,
 461                             clib_net_to_host_u16 (tcp1->dst),
 462                             format_ip4_address, &new_addr1);
 463               next1 = NAT_DET_OUT2IN_NEXT_DROP;
 464               b1->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 465               goto trace1;
 466             }
 467           old_port1 = udp1->dst_port;
 468           udp1->dst_port = new_port1 = ses1->in_port;
 469
 470           old_addr1 = ip1->dst_address;
 471           ip1->dst_address = new_addr1;
 472           vnet_buffer (b1)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 473
 474           sum1 = ip1->checksum;
 475           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 476                                  ip4_header_t,
 477                                  dst_address /* changed member */ );
 478           ip1->checksum = ip_csum_fold (sum1);
 479
 480           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
 481             {
 482               if (tcp1->flags & TCP_FLAG_FIN
 483                   && ses1->state == SNAT_SESSION_TCP_ESTABLISHED)
 484                 ses1->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 485               else if (tcp1->flags & TCP_FLAG_ACK
 486                        && ses1->state == SNAT_SESSION_TCP_LAST_ACK)
 487                 snat_det_ses_close (dm1, ses1);
 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               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 494                                      ip4_header_t /* cheat */ ,
 495                                      length /* changed member */ );
 496               tcp1->checksum = ip_csum_fold (sum1);
 497             }
 498           else if (udp1->checksum)
 499             {
 500               sum1 = udp1->checksum;
 501               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 502                                      ip4_header_t,
 503                                      dst_address /* changed member */ );
 504               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 505                                      ip4_header_t /* cheat */ ,
 506                                      length /* changed member */ );
 507               udp1->checksum = ip_csum_fold (sum1);
 508             }
 509
 510         trace1:
 511
 512           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 513                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 514             {
 515               nat_det_out2in_trace_t *t =
 516                 vlib_add_trace (vm, node, b1, sizeof (*t));
 517               t->sw_if_index = sw_if_index1;
 518               t->next_index = next1;
 519               t->session_index = ~0;
 520               if (ses1)
 521                 t->session_index = ses1 - dm1->sessions;
 522             }
 523
 524           pkts_processed += next1 != NAT_DET_OUT2IN_NEXT_DROP;
 525
 526           /* verify speculative enqueues, maybe switch current next frame */
 527           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 528                                            to_next, n_left_to_next,
 529                                            bi0, bi1, next0, next1);
 530         }
 531
 532       while (n_left_from > 0 && n_left_to_next > 0)
 533         {
 534           u32 bi0;
 535           vlib_buffer_t *b0;
 536           u32 next0 = NAT_DET_OUT2IN_NEXT_LOOKUP;
 537           u32 sw_if_index0;
 538           ip4_header_t *ip0;
 539           ip_csum_t sum0;
 540           ip4_address_t new_addr0, old_addr0;
 541           u16 new_port0, old_port0;
 542           udp_header_t *udp0;
 543           tcp_header_t *tcp0;
 544           u32 proto0;
 545           snat_det_out_key_t key0;
 546           snat_det_map_t *dm0;
 547           snat_det_session_t *ses0 = 0;
 548           u32 rx_fib_index0;
 549           icmp46_header_t *icmp0;
 550
 551           /* speculatively enqueue b0 to the current next frame */
 552           bi0 = from[0];
 553           to_next[0] = bi0;
 554           from += 1;
 555           to_next += 1;
 556           n_left_from -= 1;
 557           n_left_to_next -= 1;
 558
 559           b0 = vlib_get_buffer (vm, bi0);
 560
 561           ip0 = vlib_buffer_get_current (b0);
 562           udp0 = ip4_next_header (ip0);
 563           tcp0 = (tcp_header_t *) udp0;
 564
 565           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 566
 567           if (PREDICT_FALSE (ip0->ttl == 1))
 568             {
 569               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 570               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 571                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 572                                            0);
 573               next0 = NAT_DET_OUT2IN_NEXT_ICMP_ERROR;
 574               goto trace00;
 575             }
 576
 577           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 578
 579           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 580             {
 581               rx_fib_index0 =
 582                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 583               icmp0 = (icmp46_header_t *) udp0;
 584
 585               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
 586                                    rx_fib_index0, node, next0, thread_index,
 587                                    &ses0, &dm0);
 588               goto trace00;
 589             }
 590
 591           key0.ext_host_addr = ip0->src_address;
 592           key0.ext_host_port = tcp0->src;
 593           key0.out_port = tcp0->dst;
 594
 595           dm0 = snat_det_map_by_out (sm, &ip0->dst_address);
 596           if (PREDICT_FALSE (!dm0))
 597             {
 598               nat_log_info ("unknown dst address:  %U",
 599                             format_ip4_address, &ip0->dst_address);
 600               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 601               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 602               goto trace00;
 603             }
 604
 605           snat_det_reverse (dm0, &ip0->dst_address,
 606                             clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 607
 608           ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
 609           if (PREDICT_FALSE (!ses0))
 610             {
 611               nat_log_info ("no match src %U:%d dst %U:%d for user %U",
 612                             format_ip4_address, &ip0->src_address,
 613                             clib_net_to_host_u16 (tcp0->src),
 614                             format_ip4_address, &ip0->dst_address,
 615                             clib_net_to_host_u16 (tcp0->dst),
 616                             format_ip4_address, &new_addr0);
 617               next0 = NAT_DET_OUT2IN_NEXT_DROP;
 618               b0->error = node->errors[NAT_DET_OUT2IN_ERROR_NO_TRANSLATION];
 619               goto trace00;
 620             }
 621           old_port0 = udp0->dst_port;
 622           udp0->dst_port = new_port0 = ses0->in_port;
 623
 624           old_addr0 = ip0->dst_address;
 625           ip0->dst_address = new_addr0;
 626           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
 627
 628           sum0 = ip0->checksum;
 629           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 630                                  ip4_header_t,
 631                                  dst_address /* changed member */ );
 632           ip0->checksum = ip_csum_fold (sum0);
 633
 634           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 635             {
 636               if (tcp0->flags & TCP_FLAG_FIN
 637                   && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 638                 ses0->state = SNAT_SESSION_TCP_CLOSE_WAIT;
 639               else if (tcp0->flags & TCP_FLAG_ACK
 640                        && ses0->state == SNAT_SESSION_TCP_LAST_ACK)
 641                 snat_det_ses_close (dm0, ses0);
 642
 643               sum0 = tcp0->checksum;
 644               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 645                                      ip4_header_t,
 646                                      dst_address /* changed member */ );
 647               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 648                                      ip4_header_t /* cheat */ ,
 649                                      length /* changed member */ );
 650               tcp0->checksum = ip_csum_fold (sum0);
 651             }
 652           else if (udp0->checksum)
 653             {
 654               sum0 = udp0->checksum;
 655               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 656                                      ip4_header_t,
 657                                      dst_address /* changed member */ );
 658               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 659                                      ip4_header_t /* cheat */ ,
 660                                      length /* changed member */ );
 661               udp0->checksum = ip_csum_fold (sum0);
 662             }
 663
 664         trace00:
 665
 666           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 667                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 668             {
 669               nat_det_out2in_trace_t *t =
 670                 vlib_add_trace (vm, node, b0, sizeof (*t));
 671               t->sw_if_index = sw_if_index0;
 672               t->next_index = next0;
 673               t->session_index = ~0;
 674               if (ses0)
 675                 t->session_index = ses0 - dm0->sessions;
 676             }
 677
 678           pkts_processed += next0 != NAT_DET_OUT2IN_NEXT_DROP;
 679
 680           /* verify speculative enqueue, maybe switch current next frame */
 681           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 682                                            to_next, n_left_to_next,
 683                                            bi0, next0);
 684         }
 685
 686       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 687     }
 688
 689   vlib_node_increment_counter (vm, sm->det_out2in_node_index,
 690                                NAT_DET_OUT2IN_ERROR_OUT2IN_PACKETS,
 691                                pkts_processed);
 692   return frame->n_vectors;
 693 }
 694
 695 /* *INDENT-OFF* */
 696 VLIB_REGISTER_NODE (snat_det_out2in_node) = {
 697   .name = "nat44-det-out2in",
 698   .vector_size = sizeof (u32),
 699   .format_trace = format_nat_det_out2in_trace,
 700   .type = VLIB_NODE_TYPE_INTERNAL,
 701   .n_errors = ARRAY_LEN(nat_det_out2in_error_strings),
 702   .error_strings = nat_det_out2in_error_strings,
 703   .runtime_data_bytes = sizeof (snat_runtime_t),
 704   .n_next_nodes = NAT_DET_OUT2IN_N_NEXT,
 705   /* edit / add dispositions here */
 706   .next_nodes = {
 707     [NAT_DET_OUT2IN_NEXT_DROP] = "error-drop",
 708     [NAT_DET_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
 709     [NAT_DET_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 710   },
 711 };
 712 /* *INDENT-ON* */
 713
 714 /*
 715  * fd.io coding-style-patch-verification: ON
 716  *
 717  * Local Variables:
 718  * eval: (c-set-style "gnu")
 719  * End:
 720  */