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