src/plugins/nat/nat_det_in2out.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 inside to outside 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 struct
  31 {
  32   u32 sw_if_index;
  33   u32 next_index;
  34   u32 session_index;
  35 } nat_det_in2out_trace_t;
  36
  37 typedef enum
  38 {
  39   NAT_DET_IN2OUT_NEXT_LOOKUP,
  40   NAT_DET_IN2OUT_NEXT_DROP,
  41   NAT_DET_IN2OUT_NEXT_ICMP_ERROR,
  42   NAT_DET_IN2OUT_N_NEXT,
  43 } nat_det_in2out_next_t;
  44
  45 #define foreach_nat_det_in2out_error                    \
  46 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
  47 _(NO_TRANSLATION, "No translation")                     \
  48 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  49 _(OUT_OF_PORTS, "Out of ports")                         \
  50 _(IN2OUT_PACKETS, "Good in2out packets processed")
  51
  52 typedef enum
  53 {
  54 #define _(sym,str) NAT_DET_IN2OUT_ERROR_##sym,
  55   foreach_nat_det_in2out_error
  56 #undef _
  57     NAT_DET_IN2OUT_N_ERROR,
  58 } nat_det_in2out_error_t;
  59
  60 static char *nat_det_in2out_error_strings[] = {
  61 #define _(sym,string) string,
  62   foreach_nat_det_in2out_error
  63 #undef _
  64 };
  65
  66 static u8 *
  67 format_nat_det_in2out_trace (u8 * s, va_list * args)
  68 {
  69   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  70   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  71   nat_det_in2out_trace_t *t = va_arg (*args, nat_det_in2out_trace_t *);
  72
  73   s = format (s, "NAT_DET_IN2OUT: sw_if_index %d, next index %d, session %d",
  74               t->sw_if_index, t->next_index, t->session_index);
  75
  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_in2out_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, u8 * p_dont_translate,
 100                        void *d, void *e)
 101 {
 102   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 103   icmp46_header_t *icmp0;
 104   u32 sw_if_index0;
 105   u32 rx_fib_index0;
 106   u8 protocol;
 107   snat_det_out_key_t key0;
 108   u8 dont_translate = 0;
 109   u32 next0 = ~0;
 110   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 111   ip4_header_t *inner_ip0;
 112   void *l4_header = 0;
 113   icmp46_header_t *inner_icmp0;
 114   snat_det_map_t *dm0 = 0;
 115   ip4_address_t new_addr0;
 116   u16 lo_port0, i0;
 117   snat_det_session_t *ses0 = 0;
 118   ip4_address_t in_addr;
 119   u16 in_port;
 120
 121   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 122   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 123   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 124   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 125
 126   if (!icmp_type_is_error_message
 127       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
 128     {
 129       protocol = SNAT_PROTOCOL_ICMP;
 130       in_addr = ip0->src_address;
 131       in_port = vnet_buffer (b0)->ip.reass.l4_src_port;
 132     }
 133   else
 134     {
 135       /* if error message, then it's not fragmented and we can access it */
 136       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 137       l4_header = ip4_next_header (inner_ip0);
 138       protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 139       in_addr = inner_ip0->dst_address;
 140       switch (protocol)
 141         {
 142         case SNAT_PROTOCOL_ICMP:
 143           inner_icmp0 = (icmp46_header_t *) l4_header;
 144           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 145           in_port = inner_echo0->identifier;
 146           break;
 147         case SNAT_PROTOCOL_UDP:
 148         case SNAT_PROTOCOL_TCP:
 149           in_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 150           break;
 151         default:
 152           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
 153           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 154           goto out;
 155         }
 156     }
 157
 158   dm0 = snat_det_map_by_user (sm, &in_addr);
 159   if (PREDICT_FALSE (!dm0))
 160     {
 161       nat_log_info ("no match for internal host %U",
 162                     format_ip4_address, &in_addr);
 163       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 164                                                   IP_PROTOCOL_ICMP,
 165                                                   rx_fib_index0)))
 166         {
 167           dont_translate = 1;
 168           goto out;
 169         }
 170       next0 = NAT_DET_IN2OUT_NEXT_DROP;
 171       b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 172       goto out;
 173     }
 174
 175   snat_det_forward (dm0, &in_addr, &new_addr0, &lo_port0);
 176
 177   key0.ext_host_addr = ip0->dst_address;
 178   key0.ext_host_port = 0;
 179
 180   ses0 = snat_det_find_ses_by_in (dm0, &in_addr, in_port, key0);
 181   if (PREDICT_FALSE (!ses0))
 182     {
 183       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 184                                                   IP_PROTOCOL_ICMP,
 185                                                   rx_fib_index0)))
 186         {
 187           dont_translate = 1;
 188           goto out;
 189         }
 190       if (icmp0->type != ICMP4_echo_request)
 191         {
 192           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_BAD_ICMP_TYPE];
 193           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 194           goto out;
 195         }
 196       for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 197         {
 198           key0.out_port = clib_host_to_net_u16 (lo_port0 +
 199                                                 ((i0 +
 200                                                   clib_net_to_host_u16
 201                                                   (echo0->identifier)) %
 202                                                  dm0->ports_per_host));
 203
 204           if (snat_det_get_ses_by_out (dm0, &in_addr, key0.as_u64))
 205             continue;
 206
 207           ses0 =
 208             snat_det_ses_create (thread_index, dm0,
 209                                  &in_addr, echo0->identifier, &key0);
 210           break;
 211         }
 212       if (PREDICT_FALSE (!ses0))
 213         {
 214           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 215           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_OUT_OF_PORTS];
 216           goto out;
 217         }
 218     }
 219
 220   if (PREDICT_FALSE
 221       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_request
 222        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 223                                        reass.icmp_type_or_tcp_flags)))
 224     {
 225       b0->error = node->errors[NAT_DET_IN2OUT_ERROR_BAD_ICMP_TYPE];
 226       next0 = NAT_DET_IN2OUT_NEXT_DROP;
 227       goto out;
 228     }
 229
 230   u32 now = (u32) vlib_time_now (tsm->vlib_main);
 231
 232   ses0->state = SNAT_SESSION_ICMP_ACTIVE;
 233   ses0->expire = now + sm->icmp_timeout;
 234
 235 out:
 236   *p_proto = protocol;
 237   if (ses0)
 238     {
 239       p_value->addr = new_addr0;
 240       p_value->fib_index = sm->outside_fib_index;
 241       p_value->port = ses0->out.out_port;
 242     }
 243   *p_dont_translate = dont_translate;
 244   if (d)
 245     *(snat_det_session_t **) d = ses0;
 246   if (e)
 247     *(snat_det_map_t **) e = dm0;
 248   return next0;
 249 }
 250 #endif
 251
 252 VLIB_NODE_FN (snat_det_in2out_node) (vlib_main_t * vm,
 253                                      vlib_node_runtime_t * node,
 254                                      vlib_frame_t * frame)
 255 {
 256   u32 n_left_from, *from, *to_next;
 257   nat_det_in2out_next_t next_index;
 258   u32 pkts_processed = 0;
 259   snat_main_t *sm = &snat_main;
 260   u32 now = (u32) vlib_time_now (vm);
 261   u32 thread_index = vm->thread_index;
 262
 263   from = vlib_frame_vector_args (frame);
 264   n_left_from = frame->n_vectors;
 265   next_index = node->cached_next_index;
 266
 267   while (n_left_from > 0)
 268     {
 269       u32 n_left_to_next;
 270
 271       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 272
 273       while (n_left_from >= 4 && n_left_to_next >= 2)
 274         {
 275           u32 bi0, bi1;
 276           vlib_buffer_t *b0, *b1;
 277           u32 next0, next1;
 278           u32 sw_if_index0, sw_if_index1;
 279           ip4_header_t *ip0, *ip1;
 280           ip_csum_t sum0, sum1;
 281           ip4_address_t new_addr0, old_addr0, new_addr1, old_addr1;
 282           u16 old_port0, new_port0, lo_port0, i0;
 283           u16 old_port1, new_port1, lo_port1, i1;
 284           udp_header_t *udp0, *udp1;
 285           tcp_header_t *tcp0, *tcp1;
 286           u32 proto0, proto1;
 287           snat_det_out_key_t key0, key1;
 288           snat_det_map_t *dm0, *dm1;
 289           snat_det_session_t *ses0 = 0, *ses1 = 0;
 290           u32 rx_fib_index0, rx_fib_index1;
 291           icmp46_header_t *icmp0, *icmp1;
 292
 293           /* Prefetch next iteration. */
 294           {
 295             vlib_buffer_t *p2, *p3;
 296
 297             p2 = vlib_get_buffer (vm, from[2]);
 298             p3 = vlib_get_buffer (vm, from[3]);
 299
 300             vlib_prefetch_buffer_header (p2, LOAD);
 301             vlib_prefetch_buffer_header (p3, LOAD);
 302
 303             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 304             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 305           }
 306
 307           /* speculatively enqueue b0 and b1 to the current next frame */
 308           to_next[0] = bi0 = from[0];
 309           to_next[1] = bi1 = from[1];
 310           from += 2;
 311           to_next += 2;
 312           n_left_from -= 2;
 313           n_left_to_next -= 2;
 314
 315           b0 = vlib_get_buffer (vm, bi0);
 316           b1 = vlib_get_buffer (vm, bi1);
 317
 318           next0 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 319           next1 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 320
 321           ip0 = vlib_buffer_get_current (b0);
 322           udp0 = ip4_next_header (ip0);
 323           tcp0 = (tcp_header_t *) udp0;
 324
 325           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 326
 327           if (PREDICT_FALSE (ip0->ttl == 1))
 328             {
 329               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 330               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 331                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 332                                            0);
 333               next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 334               goto trace0;
 335             }
 336
 337           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 338
 339           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 340             {
 341               rx_fib_index0 =
 342                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 343               icmp0 = (icmp46_header_t *) udp0;
 344
 345               next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0,
 346                                    rx_fib_index0, node, next0, thread_index,
 347                                    &ses0, &dm0);
 348               goto trace0;
 349             }
 350
 351           dm0 = snat_det_map_by_user (sm, &ip0->src_address);
 352           if (PREDICT_FALSE (!dm0))
 353             {
 354               nat_log_info ("no match for internal host %U",
 355                             format_ip4_address, &ip0->src_address);
 356               next0 = NAT_DET_IN2OUT_NEXT_DROP;
 357               b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 358               goto trace0;
 359             }
 360
 361           snat_det_forward (dm0, &ip0->src_address, &new_addr0, &lo_port0);
 362
 363           key0.ext_host_addr = ip0->dst_address;
 364           key0.ext_host_port = tcp0->dst;
 365
 366           ses0 =
 367             snat_det_find_ses_by_in (dm0, &ip0->src_address, tcp0->src, key0);
 368           if (PREDICT_FALSE (!ses0))
 369             {
 370               for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 371                 {
 372                   key0.out_port = clib_host_to_net_u16 (lo_port0 +
 373                                                         ((i0 +
 374                                                           clib_net_to_host_u16
 375                                                           (tcp0->src)) %
 376                                                          dm0->
 377                                                          ports_per_host));
 378
 379                   if (snat_det_get_ses_by_out
 380                       (dm0, &ip0->src_address, key0.as_u64))
 381                     continue;
 382
 383                   ses0 =
 384                     snat_det_ses_create (thread_index, dm0, &ip0->src_address,
 385                                          tcp0->src, &key0);
 386                   break;
 387                 }
 388               if (PREDICT_FALSE (!ses0))
 389                 {
 390                   /* too many sessions for user, send ICMP error packet */
 391                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 392                   icmp4_error_set_vnet_buffer (b0,
 393                                                ICMP4_destination_unreachable,
 394                                                ICMP4_destination_unreachable_destination_unreachable_host,
 395                                                0);
 396                   next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 397                   goto trace0;
 398                 }
 399             }
 400
 401           old_port0 = udp0->src_port;
 402           udp0->src_port = new_port0 = ses0->out.out_port;
 403
 404           old_addr0.as_u32 = ip0->src_address.as_u32;
 405           ip0->src_address.as_u32 = new_addr0.as_u32;
 406           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 407
 408           sum0 = ip0->checksum;
 409           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 410                                  ip4_header_t,
 411                                  src_address /* changed member */ );
 412           ip0->checksum = ip_csum_fold (sum0);
 413
 414           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 415             {
 416               if (tcp0->flags & TCP_FLAG_SYN)
 417                 ses0->state = SNAT_SESSION_TCP_SYN_SENT;
 418               else if (tcp0->flags & TCP_FLAG_ACK
 419                        && ses0->state == SNAT_SESSION_TCP_SYN_SENT)
 420                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 421               else if (tcp0->flags & TCP_FLAG_FIN
 422                        && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 423                 ses0->state = SNAT_SESSION_TCP_FIN_WAIT;
 424               else if (tcp0->flags & TCP_FLAG_ACK
 425                        && ses0->state == SNAT_SESSION_TCP_FIN_WAIT)
 426                 snat_det_ses_close (dm0, ses0);
 427               else if (tcp0->flags & TCP_FLAG_FIN
 428                        && ses0->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 429                 ses0->state = SNAT_SESSION_TCP_LAST_ACK;
 430               else if (tcp0->flags == 0
 431                        && ses0->state == SNAT_SESSION_UNKNOWN)
 432                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 433
 434               sum0 = tcp0->checksum;
 435               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 436                                      ip4_header_t,
 437                                      dst_address /* changed member */ );
 438               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 439                                      ip4_header_t /* cheat */ ,
 440                                      length /* changed member */ );
 441               mss_clamping (sm, tcp0, &sum0);
 442               tcp0->checksum = ip_csum_fold (sum0);
 443             }
 444           else
 445             {
 446               ses0->state = SNAT_SESSION_UDP_ACTIVE;
 447
 448               if (PREDICT_FALSE (udp0->checksum))
 449                 {
 450                   sum0 = udp0->checksum;
 451                   sum0 =
 452                     ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 453                                     ip4_header_t,
 454                                     dst_address /* changed member */ );
 455                   sum0 =
 456                     ip_csum_update (sum0, old_port0, new_port0,
 457                                     ip4_header_t /* cheat */ ,
 458                                     length /* changed member */ );
 459                   udp0->checksum = ip_csum_fold (sum0);
 460                 }
 461             }
 462
 463           switch (ses0->state)
 464             {
 465             case SNAT_SESSION_UDP_ACTIVE:
 466               ses0->expire = now + sm->udp_timeout;
 467               break;
 468             case SNAT_SESSION_TCP_SYN_SENT:
 469             case SNAT_SESSION_TCP_FIN_WAIT:
 470             case SNAT_SESSION_TCP_CLOSE_WAIT:
 471             case SNAT_SESSION_TCP_LAST_ACK:
 472               ses0->expire = now + sm->tcp_transitory_timeout;
 473               break;
 474             case SNAT_SESSION_TCP_ESTABLISHED:
 475               ses0->expire = now + sm->tcp_established_timeout;
 476               break;
 477             }
 478
 479         trace0:
 480           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 481                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 482             {
 483               nat_det_in2out_trace_t *t =
 484                 vlib_add_trace (vm, node, b0, sizeof (*t));
 485               t->sw_if_index = sw_if_index0;
 486               t->next_index = next0;
 487               t->session_index = ~0;
 488               if (ses0)
 489                 t->session_index = ses0 - dm0->sessions;
 490             }
 491
 492           pkts_processed += next0 != NAT_DET_IN2OUT_NEXT_DROP;
 493
 494           ip1 = vlib_buffer_get_current (b1);
 495           udp1 = ip4_next_header (ip1);
 496           tcp1 = (tcp_header_t *) udp1;
 497
 498           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 499
 500           if (PREDICT_FALSE (ip1->ttl == 1))
 501             {
 502               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 503               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 504                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 505                                            0);
 506               next1 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 507               goto trace1;
 508             }
 509
 510           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 511
 512           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
 513             {
 514               rx_fib_index1 =
 515                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 516               icmp1 = (icmp46_header_t *) udp1;
 517
 518               next1 = icmp_in2out (sm, b1, ip1, icmp1, sw_if_index1,
 519                                    rx_fib_index1, node, next1, thread_index,
 520                                    &ses1, &dm1);
 521               goto trace1;
 522             }
 523
 524           dm1 = snat_det_map_by_user (sm, &ip1->src_address);
 525           if (PREDICT_FALSE (!dm1))
 526             {
 527               nat_log_info ("no match for internal host %U",
 528                             format_ip4_address, &ip0->src_address);
 529               next1 = NAT_DET_IN2OUT_NEXT_DROP;
 530               b1->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 531               goto trace1;
 532             }
 533
 534           snat_det_forward (dm1, &ip1->src_address, &new_addr1, &lo_port1);
 535
 536           key1.ext_host_addr = ip1->dst_address;
 537           key1.ext_host_port = tcp1->dst;
 538
 539           ses1 =
 540             snat_det_find_ses_by_in (dm1, &ip1->src_address, tcp1->src, key1);
 541           if (PREDICT_FALSE (!ses1))
 542             {
 543               for (i1 = 0; i1 < dm1->ports_per_host; i1++)
 544                 {
 545                   key1.out_port = clib_host_to_net_u16 (lo_port1 +
 546                                                         ((i1 +
 547                                                           clib_net_to_host_u16
 548                                                           (tcp1->src)) %
 549                                                          dm1->
 550                                                          ports_per_host));
 551
 552                   if (snat_det_get_ses_by_out
 553                       (dm1, &ip1->src_address, key1.as_u64))
 554                     continue;
 555
 556                   ses1 =
 557                     snat_det_ses_create (thread_index, dm1, &ip1->src_address,
 558                                          tcp1->src, &key1);
 559                   break;
 560                 }
 561               if (PREDICT_FALSE (!ses1))
 562                 {
 563                   /* too many sessions for user, send ICMP error packet */
 564                   vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 565                   icmp4_error_set_vnet_buffer (b1,
 566                                                ICMP4_destination_unreachable,
 567                                                ICMP4_destination_unreachable_destination_unreachable_host,
 568                                                0);
 569                   next1 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 570                   goto trace1;
 571                 }
 572             }
 573
 574           old_port1 = udp1->src_port;
 575           udp1->src_port = new_port1 = ses1->out.out_port;
 576
 577           old_addr1.as_u32 = ip1->src_address.as_u32;
 578           ip1->src_address.as_u32 = new_addr1.as_u32;
 579           vnet_buffer (b1)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 580
 581           sum1 = ip1->checksum;
 582           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 583                                  ip4_header_t,
 584                                  src_address /* changed member */ );
 585           ip1->checksum = ip_csum_fold (sum1);
 586
 587           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
 588             {
 589               if (tcp1->flags & TCP_FLAG_SYN)
 590                 ses1->state = SNAT_SESSION_TCP_SYN_SENT;
 591               else if (tcp1->flags & TCP_FLAG_ACK
 592                        && ses1->state == SNAT_SESSION_TCP_SYN_SENT)
 593                 ses1->state = SNAT_SESSION_TCP_ESTABLISHED;
 594               else if (tcp1->flags & TCP_FLAG_FIN
 595                        && ses1->state == SNAT_SESSION_TCP_ESTABLISHED)
 596                 ses1->state = SNAT_SESSION_TCP_FIN_WAIT;
 597               else if (tcp1->flags & TCP_FLAG_ACK
 598                        && ses1->state == SNAT_SESSION_TCP_FIN_WAIT)
 599                 snat_det_ses_close (dm1, ses1);
 600               else if (tcp1->flags & TCP_FLAG_FIN
 601                        && ses1->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 602                 ses1->state = SNAT_SESSION_TCP_LAST_ACK;
 603               else if (tcp1->flags == 0
 604                        && ses1->state == SNAT_SESSION_UNKNOWN)
 605                 ses1->state = SNAT_SESSION_TCP_ESTABLISHED;
 606
 607               sum1 = tcp1->checksum;
 608               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 609                                      ip4_header_t,
 610                                      dst_address /* changed member */ );
 611               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 612                                      ip4_header_t /* cheat */ ,
 613                                      length /* changed member */ );
 614               mss_clamping (sm, tcp1, &sum1);
 615               tcp1->checksum = ip_csum_fold (sum1);
 616             }
 617           else
 618             {
 619               ses1->state = SNAT_SESSION_UDP_ACTIVE;
 620
 621               if (PREDICT_FALSE (udp1->checksum))
 622                 {
 623                   sum1 = udp1->checksum;
 624                   sum1 =
 625                     ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 626                                     ip4_header_t,
 627                                     dst_address /* changed member */ );
 628                   sum1 =
 629                     ip_csum_update (sum1, old_port1, new_port1,
 630                                     ip4_header_t /* cheat */ ,
 631                                     length /* changed member */ );
 632                   udp1->checksum = ip_csum_fold (sum1);
 633                 }
 634             }
 635
 636           switch (ses1->state)
 637             {
 638             case SNAT_SESSION_UDP_ACTIVE:
 639               ses1->expire = now + sm->udp_timeout;
 640               break;
 641             case SNAT_SESSION_TCP_SYN_SENT:
 642             case SNAT_SESSION_TCP_FIN_WAIT:
 643             case SNAT_SESSION_TCP_CLOSE_WAIT:
 644             case SNAT_SESSION_TCP_LAST_ACK:
 645               ses1->expire = now + sm->tcp_transitory_timeout;
 646               break;
 647             case SNAT_SESSION_TCP_ESTABLISHED:
 648               ses1->expire = now + sm->tcp_established_timeout;
 649               break;
 650             }
 651
 652         trace1:
 653           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 654                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 655             {
 656               nat_det_in2out_trace_t *t =
 657                 vlib_add_trace (vm, node, b1, sizeof (*t));
 658               t->sw_if_index = sw_if_index1;
 659               t->next_index = next1;
 660               t->session_index = ~0;
 661               if (ses1)
 662                 t->session_index = ses1 - dm1->sessions;
 663             }
 664
 665           pkts_processed += next1 != NAT_DET_IN2OUT_NEXT_DROP;
 666
 667           /* verify speculative enqueues, maybe switch current next frame */
 668           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 669                                            to_next, n_left_to_next,
 670                                            bi0, bi1, next0, next1);
 671         }
 672
 673       while (n_left_from > 0 && n_left_to_next > 0)
 674         {
 675           u32 bi0;
 676           vlib_buffer_t *b0;
 677           u32 next0;
 678           u32 sw_if_index0;
 679           ip4_header_t *ip0;
 680           ip_csum_t sum0;
 681           ip4_address_t new_addr0, old_addr0;
 682           u16 old_port0, new_port0, lo_port0, i0;
 683           udp_header_t *udp0;
 684           tcp_header_t *tcp0;
 685           u32 proto0;
 686           snat_det_out_key_t key0;
 687           snat_det_map_t *dm0;
 688           snat_det_session_t *ses0 = 0;
 689           u32 rx_fib_index0;
 690           icmp46_header_t *icmp0;
 691
 692           /* speculatively enqueue b0 to the current next frame */
 693           bi0 = from[0];
 694           to_next[0] = bi0;
 695           from += 1;
 696           to_next += 1;
 697           n_left_from -= 1;
 698           n_left_to_next -= 1;
 699
 700           b0 = vlib_get_buffer (vm, bi0);
 701           next0 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 702
 703           ip0 = vlib_buffer_get_current (b0);
 704           udp0 = ip4_next_header (ip0);
 705           tcp0 = (tcp_header_t *) udp0;
 706
 707           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 708
 709           if (PREDICT_FALSE (ip0->ttl == 1))
 710             {
 711               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 712               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 713                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 714                                            0);
 715               next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 716               goto trace00;
 717             }
 718
 719           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 720
 721           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 722             {
 723               rx_fib_index0 =
 724                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 725               icmp0 = (icmp46_header_t *) udp0;
 726
 727               next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0,
 728                                    rx_fib_index0, node, next0, thread_index,
 729                                    &ses0, &dm0);
 730               goto trace00;
 731             }
 732
 733           dm0 = snat_det_map_by_user (sm, &ip0->src_address);
 734           if (PREDICT_FALSE (!dm0))
 735             {
 736               nat_log_info ("no match for internal host %U",
 737                             format_ip4_address, &ip0->src_address);
 738               next0 = NAT_DET_IN2OUT_NEXT_DROP;
 739               b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 740               goto trace00;
 741             }
 742
 743           snat_det_forward (dm0, &ip0->src_address, &new_addr0, &lo_port0);
 744
 745           key0.ext_host_addr = ip0->dst_address;
 746           key0.ext_host_port = tcp0->dst;
 747
 748           ses0 =
 749             snat_det_find_ses_by_in (dm0, &ip0->src_address, tcp0->src, key0);
 750           if (PREDICT_FALSE (!ses0))
 751             {
 752               for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 753                 {
 754                   key0.out_port = clib_host_to_net_u16 (lo_port0 +
 755                                                         ((i0 +
 756                                                           clib_net_to_host_u16
 757                                                           (tcp0->src)) %
 758                                                          dm0->
 759                                                          ports_per_host));
 760
 761                   if (snat_det_get_ses_by_out
 762                       (dm0, &ip0->src_address, key0.as_u64))
 763                     continue;
 764
 765                   ses0 =
 766                     snat_det_ses_create (thread_index, dm0, &ip0->src_address,
 767                                          tcp0->src, &key0);
 768                   break;
 769                 }
 770               if (PREDICT_FALSE (!ses0))
 771                 {
 772                   /* too many sessions for user, send ICMP error packet */
 773                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 774                   icmp4_error_set_vnet_buffer (b0,
 775                                                ICMP4_destination_unreachable,
 776                                                ICMP4_destination_unreachable_destination_unreachable_host,
 777                                                0);
 778                   next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 779                   goto trace00;
 780                 }
 781             }
 782
 783           old_port0 = udp0->src_port;
 784           udp0->src_port = new_port0 = ses0->out.out_port;
 785
 786           old_addr0.as_u32 = ip0->src_address.as_u32;
 787           ip0->src_address.as_u32 = new_addr0.as_u32;
 788           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 789
 790           sum0 = ip0->checksum;
 791           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 792                                  ip4_header_t,
 793                                  src_address /* changed member */ );
 794           ip0->checksum = ip_csum_fold (sum0);
 795
 796           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 797             {
 798               if (tcp0->flags & TCP_FLAG_SYN)
 799                 ses0->state = SNAT_SESSION_TCP_SYN_SENT;
 800               else if (tcp0->flags & TCP_FLAG_ACK
 801                        && ses0->state == SNAT_SESSION_TCP_SYN_SENT)
 802                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 803               else if (tcp0->flags & TCP_FLAG_FIN
 804                        && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 805                 ses0->state = SNAT_SESSION_TCP_FIN_WAIT;
 806               else if (tcp0->flags & TCP_FLAG_ACK
 807                        && ses0->state == SNAT_SESSION_TCP_FIN_WAIT)
 808                 snat_det_ses_close (dm0, ses0);
 809               else if (tcp0->flags & TCP_FLAG_FIN
 810                        && ses0->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 811                 ses0->state = SNAT_SESSION_TCP_LAST_ACK;
 812               else if (tcp0->flags == 0
 813                        && ses0->state == SNAT_SESSION_UNKNOWN)
 814                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 815
 816               sum0 = tcp0->checksum;
 817               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 818                                      ip4_header_t,
 819                                      dst_address /* changed member */ );
 820               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 821                                      ip4_header_t /* cheat */ ,
 822                                      length /* changed member */ );
 823               mss_clamping (sm, tcp0, &sum0);
 824               tcp0->checksum = ip_csum_fold (sum0);
 825             }
 826           else
 827             {
 828               ses0->state = SNAT_SESSION_UDP_ACTIVE;
 829
 830               if (PREDICT_FALSE (udp0->checksum))
 831                 {
 832                   sum0 = udp0->checksum;
 833                   sum0 =
 834                     ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 835                                     ip4_header_t,
 836                                     dst_address /* changed member */ );
 837                   sum0 =
 838                     ip_csum_update (sum0, old_port0, new_port0,
 839                                     ip4_header_t /* cheat */ ,
 840                                     length /* changed member */ );
 841                   udp0->checksum = ip_csum_fold (sum0);
 842                 }
 843             }
 844
 845           switch (ses0->state)
 846             {
 847             case SNAT_SESSION_UDP_ACTIVE:
 848               ses0->expire = now + sm->udp_timeout;
 849               break;
 850             case SNAT_SESSION_TCP_SYN_SENT:
 851             case SNAT_SESSION_TCP_FIN_WAIT:
 852             case SNAT_SESSION_TCP_CLOSE_WAIT:
 853             case SNAT_SESSION_TCP_LAST_ACK:
 854               ses0->expire = now + sm->tcp_transitory_timeout;
 855               break;
 856             case SNAT_SESSION_TCP_ESTABLISHED:
 857               ses0->expire = now + sm->tcp_established_timeout;
 858               break;
 859             }
 860
 861         trace00:
 862           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 863                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 864             {
 865               nat_det_in2out_trace_t *t =
 866                 vlib_add_trace (vm, node, b0, sizeof (*t));
 867               t->sw_if_index = sw_if_index0;
 868               t->next_index = next0;
 869               t->session_index = ~0;
 870               if (ses0)
 871                 t->session_index = ses0 - dm0->sessions;
 872             }
 873
 874           pkts_processed += next0 != NAT_DET_IN2OUT_NEXT_DROP;
 875
 876           /* verify speculative enqueue, maybe switch current next frame */
 877           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 878                                            to_next, n_left_to_next,
 879                                            bi0, next0);
 880         }
 881
 882       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 883     }
 884
 885   vlib_node_increment_counter (vm, sm->det_in2out_node_index,
 886                                NAT_DET_IN2OUT_ERROR_IN2OUT_PACKETS,
 887                                pkts_processed);
 888   return frame->n_vectors;
 889 }
 890
 891 /* *INDENT-OFF* */
 892 VLIB_REGISTER_NODE (snat_det_in2out_node) = {
 893   .name = "nat44-det-in2out",
 894   .vector_size = sizeof (u32),
 895   .format_trace = format_nat_det_in2out_trace,
 896   .type = VLIB_NODE_TYPE_INTERNAL,
 897   .n_errors = ARRAY_LEN(nat_det_in2out_error_strings),
 898   .error_strings = nat_det_in2out_error_strings,
 899   .n_next_nodes = NAT_DET_IN2OUT_N_NEXT,
 900   /* edit / add dispositions here */
 901   .next_nodes = {
 902     [NAT_DET_IN2OUT_NEXT_DROP] = "error-drop",
 903     [NAT_DET_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
 904     [NAT_DET_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 905   },
 906 };
 907 /* *INDENT-ON* */
 908
 909 /*
 910  * fd.io coding-style-patch-verification: ON
 911  *
 912  * Local Variables:
 913  * eval: (c-set-style "gnu")
 914  * End:
 915  */