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 #include <nat/lib/nat_inlines.h>
  30
  31 typedef struct
  32 {
  33   u32 sw_if_index;
  34   u32 next_index;
  35   u32 session_index;
  36 } nat_det_in2out_trace_t;
  37
  38 typedef enum
  39 {
  40   NAT_DET_IN2OUT_NEXT_LOOKUP,
  41   NAT_DET_IN2OUT_NEXT_DROP,
  42   NAT_DET_IN2OUT_NEXT_ICMP_ERROR,
  43   NAT_DET_IN2OUT_N_NEXT,
  44 } nat_det_in2out_next_t;
  45
  46 #define foreach_nat_det_in2out_error                    \
  47 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
  48 _(NO_TRANSLATION, "No translation")                     \
  49 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  50 _(OUT_OF_PORTS, "Out of ports")                         \
  51 _(IN2OUT_PACKETS, "Good in2out packets processed")
  52
  53 typedef enum
  54 {
  55 #define _(sym,str) NAT_DET_IN2OUT_ERROR_##sym,
  56   foreach_nat_det_in2out_error
  57 #undef _
  58     NAT_DET_IN2OUT_N_ERROR,
  59 } nat_det_in2out_error_t;
  60
  61 static char *nat_det_in2out_error_strings[] = {
  62 #define _(sym,string) string,
  63   foreach_nat_det_in2out_error
  64 #undef _
  65 };
  66
  67 static u8 *
  68 format_nat_det_in2out_trace (u8 * s, va_list * args)
  69 {
  70   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  71   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  72   nat_det_in2out_trace_t *t = va_arg (*args, nat_det_in2out_trace_t *);
  73
  74   s = format (s, "NAT_DET_IN2OUT: sw_if_index %d, next index %d, session %d",
  75               t->sw_if_index, t->next_index, t->session_index);
  76
  77   return s;
  78 }
  79
  80 #ifndef CLIB_MARCH_VARIANT
  81 /**
  82  * Get address and port values to be used for ICMP packet translation
  83  * and create session if needed
  84  *
  85  * @param[in,out] sm             NAT main
  86  * @param[in,out] node           NAT node runtime
  87  * @param[in] thread_index       thread index
  88  * @param[in,out] b0             buffer containing packet to be translated
  89  * @param[in,out] ip0            ip header
  90  * @param[out] p_proto           protocol used for matching
  91  * @param[out] p_value           address and port after NAT translation
  92  * @param[out] p_dont_translate  if packet should not be translated
  93  * @param d                      optional parameter
  94  * @param e                      optional parameter
  95  */
  96 u32
  97 icmp_match_in2out_det (snat_main_t * sm, vlib_node_runtime_t * node,
  98                        u32 thread_index, vlib_buffer_t * b0,
  99                        ip4_header_t * ip0, ip4_address_t * addr,
 100                        u16 * port, u32 * fib_index,
 101                        nat_protocol_t * proto, void *d, void *e,
 102                        u8 * dont_translate)
 103 {
 104   vlib_main_t *vm = vlib_get_main ();
 105   icmp46_header_t *icmp0;
 106   u32 sw_if_index0;
 107   u32 rx_fib_index0;
 108   nat_protocol_t protocol;
 109   snat_det_out_key_t key0;
 110   u32 next0 = ~0;
 111   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 112   ip4_header_t *inner_ip0;
 113   void *l4_header = 0;
 114   icmp46_header_t *inner_icmp0;
 115   snat_det_map_t *dm0 = 0;
 116   ip4_address_t new_addr0;
 117   u16 lo_port0, i0;
 118   snat_det_session_t *ses0 = 0;
 119   ip4_address_t in_addr;
 120   u16 in_port;
 121   *dont_translate = 0;
 122
 123   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 124   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 125   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 126   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 127
 128   if (!icmp_type_is_error_message
 129       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
 130     {
 131       protocol = NAT_PROTOCOL_ICMP;
 132       in_addr = ip0->src_address;
 133       in_port = vnet_buffer (b0)->ip.reass.l4_src_port;
 134     }
 135   else
 136     {
 137       /* if error message, then it's not fragmented and we can access it */
 138       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 139       l4_header = ip4_next_header (inner_ip0);
 140       protocol = ip_proto_to_nat_proto (inner_ip0->protocol);
 141       in_addr = inner_ip0->dst_address;
 142       switch (protocol)
 143         {
 144         case NAT_PROTOCOL_ICMP:
 145           inner_icmp0 = (icmp46_header_t *) l4_header;
 146           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 147           in_port = inner_echo0->identifier;
 148           break;
 149         case NAT_PROTOCOL_UDP:
 150         case NAT_PROTOCOL_TCP:
 151           in_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 152           break;
 153         default:
 154           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
 155           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 156           goto out;
 157         }
 158     }
 159
 160   dm0 = snat_det_map_by_user (sm, &in_addr);
 161   if (PREDICT_FALSE (!dm0))
 162     {
 163       nat_log_info ("no match for internal host %U",
 164                     format_ip4_address, &in_addr);
 165       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 166                                                   IP_PROTOCOL_ICMP,
 167                                                   rx_fib_index0)))
 168         {
 169           *dont_translate = 1;
 170           goto out;
 171         }
 172       next0 = NAT_DET_IN2OUT_NEXT_DROP;
 173       b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 174       goto out;
 175     }
 176
 177   snat_det_forward (dm0, &in_addr, &new_addr0, &lo_port0);
 178
 179   key0.ext_host_addr = ip0->dst_address;
 180   key0.ext_host_port = 0;
 181
 182   ses0 = snat_det_find_ses_by_in (dm0, &in_addr, in_port, key0);
 183   if (PREDICT_FALSE (!ses0))
 184     {
 185       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 186                                                   IP_PROTOCOL_ICMP,
 187                                                   rx_fib_index0)))
 188         {
 189           *dont_translate = 1;
 190           goto out;
 191         }
 192       if (icmp0->type != ICMP4_echo_request)
 193         {
 194           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_BAD_ICMP_TYPE];
 195           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 196           goto out;
 197         }
 198       for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 199         {
 200           key0.out_port = clib_host_to_net_u16 (lo_port0 +
 201                                                 ((i0 +
 202                                                   clib_net_to_host_u16
 203                                                   (echo0->identifier)) %
 204                                                  dm0->ports_per_host));
 205
 206           if (snat_det_get_ses_by_out (dm0, &in_addr, key0.as_u64))
 207             continue;
 208
 209           ses0 =
 210             snat_det_ses_create (thread_index, dm0,
 211                                  &in_addr, echo0->identifier, &key0);
 212           break;
 213         }
 214       if (PREDICT_FALSE (!ses0))
 215         {
 216           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 217           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_OUT_OF_PORTS];
 218           goto out;
 219         }
 220     }
 221
 222   if (PREDICT_FALSE
 223       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_request
 224        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 225                                        reass.icmp_type_or_tcp_flags)))
 226     {
 227       b0->error = node->errors[NAT_DET_IN2OUT_ERROR_BAD_ICMP_TYPE];
 228       next0 = NAT_DET_IN2OUT_NEXT_DROP;
 229       goto out;
 230     }
 231
 232   u32 now = (u32) vlib_time_now (vm);
 233
 234   ses0->state = SNAT_SESSION_ICMP_ACTIVE;
 235   ses0->expire = now + sm->icmp_timeout;
 236
 237 out:
 238   *proto = protocol;
 239   if (ses0)
 240     {
 241       *addr = new_addr0;
 242       *fib_index = sm->outside_fib_index;
 243       *port = ses0->out.out_port;
 244     }
 245   if (d)
 246     *(snat_det_session_t **) d = ses0;
 247   if (e)
 248     *(snat_det_map_t **) e = dm0;
 249   return next0;
 250 }
 251 #endif
 252
 253 VLIB_NODE_FN (snat_det_in2out_node) (vlib_main_t * vm,
 254                                      vlib_node_runtime_t * node,
 255                                      vlib_frame_t * frame)
 256 {
 257   u32 n_left_from, *from, *to_next;
 258   nat_det_in2out_next_t next_index;
 259   u32 pkts_processed = 0;
 260   snat_main_t *sm = &snat_main;
 261   u32 now = (u32) vlib_time_now (vm);
 262   u32 thread_index = vm->thread_index;
 263
 264   from = vlib_frame_vector_args (frame);
 265   n_left_from = frame->n_vectors;
 266   next_index = node->cached_next_index;
 267
 268   while (n_left_from > 0)
 269     {
 270       u32 n_left_to_next;
 271
 272       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 273
 274       while (n_left_from >= 4 && n_left_to_next >= 2)
 275         {
 276           u32 bi0, bi1;
 277           vlib_buffer_t *b0, *b1;
 278           u32 next0, next1;
 279           u32 sw_if_index0, sw_if_index1;
 280           ip4_header_t *ip0, *ip1;
 281           ip_csum_t sum0, sum1;
 282           ip4_address_t new_addr0, old_addr0, new_addr1, old_addr1;
 283           u16 old_port0, new_port0, lo_port0, i0;
 284           u16 old_port1, new_port1, lo_port1, i1;
 285           udp_header_t *udp0, *udp1;
 286           tcp_header_t *tcp0, *tcp1;
 287           u32 proto0, proto1;
 288           snat_det_out_key_t key0, key1;
 289           snat_det_map_t *dm0, *dm1;
 290           snat_det_session_t *ses0 = 0, *ses1 = 0;
 291           u32 rx_fib_index0, rx_fib_index1;
 292           icmp46_header_t *icmp0, *icmp1;
 293
 294           /* Prefetch next iteration. */
 295           {
 296             vlib_buffer_t *p2, *p3;
 297
 298             p2 = vlib_get_buffer (vm, from[2]);
 299             p3 = vlib_get_buffer (vm, from[3]);
 300
 301             vlib_prefetch_buffer_header (p2, LOAD);
 302             vlib_prefetch_buffer_header (p3, LOAD);
 303
 304             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
 305             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
 306           }
 307
 308           /* speculatively enqueue b0 and b1 to the current next frame */
 309           to_next[0] = bi0 = from[0];
 310           to_next[1] = bi1 = from[1];
 311           from += 2;
 312           to_next += 2;
 313           n_left_from -= 2;
 314           n_left_to_next -= 2;
 315
 316           b0 = vlib_get_buffer (vm, bi0);
 317           b1 = vlib_get_buffer (vm, bi1);
 318
 319           next0 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 320           next1 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 321
 322           ip0 = vlib_buffer_get_current (b0);
 323           udp0 = ip4_next_header (ip0);
 324           tcp0 = (tcp_header_t *) udp0;
 325
 326           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 327
 328           if (PREDICT_FALSE (ip0->ttl == 1))
 329             {
 330               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 331               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 332                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 333                                            0);
 334               next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 335               goto trace0;
 336             }
 337
 338           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 339
 340           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 341             {
 342               rx_fib_index0 =
 343                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 344               icmp0 = (icmp46_header_t *) udp0;
 345
 346               next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0,
 347                                    rx_fib_index0, node, next0, thread_index,
 348                                    &ses0, &dm0);
 349               goto trace0;
 350             }
 351
 352           dm0 = snat_det_map_by_user (sm, &ip0->src_address);
 353           if (PREDICT_FALSE (!dm0))
 354             {
 355               nat_log_info ("no match for internal host %U",
 356                             format_ip4_address, &ip0->src_address);
 357               next0 = NAT_DET_IN2OUT_NEXT_DROP;
 358               b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 359               goto trace0;
 360             }
 361
 362           snat_det_forward (dm0, &ip0->src_address, &new_addr0, &lo_port0);
 363
 364           key0.ext_host_addr = ip0->dst_address;
 365           key0.ext_host_port = tcp0->dst;
 366
 367           ses0 =
 368             snat_det_find_ses_by_in (dm0, &ip0->src_address, tcp0->src, key0);
 369           if (PREDICT_FALSE (!ses0))
 370             {
 371               for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 372                 {
 373                   key0.out_port = clib_host_to_net_u16 (lo_port0 +
 374                                                         ((i0 +
 375                                                           clib_net_to_host_u16
 376                                                           (tcp0->src)) %
 377                                                          dm0->
 378                                                          ports_per_host));
 379
 380                   if (snat_det_get_ses_by_out
 381                       (dm0, &ip0->src_address, key0.as_u64))
 382                     continue;
 383
 384                   ses0 =
 385                     snat_det_ses_create (thread_index, dm0, &ip0->src_address,
 386                                          tcp0->src, &key0);
 387                   break;
 388                 }
 389               if (PREDICT_FALSE (!ses0))
 390                 {
 391                   /* too many sessions for user, send ICMP error packet */
 392                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 393                   icmp4_error_set_vnet_buffer (b0,
 394                                                ICMP4_destination_unreachable,
 395                                                ICMP4_destination_unreachable_destination_unreachable_host,
 396                                                0);
 397                   next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 398                   goto trace0;
 399                 }
 400             }
 401
 402           old_port0 = udp0->src_port;
 403           udp0->src_port = new_port0 = ses0->out.out_port;
 404
 405           old_addr0.as_u32 = ip0->src_address.as_u32;
 406           ip0->src_address.as_u32 = new_addr0.as_u32;
 407           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 408
 409           sum0 = ip0->checksum;
 410           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 411                                  ip4_header_t,
 412                                  src_address /* changed member */ );
 413           ip0->checksum = ip_csum_fold (sum0);
 414
 415           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 416             {
 417               if (tcp0->flags & TCP_FLAG_SYN)
 418                 ses0->state = SNAT_SESSION_TCP_SYN_SENT;
 419               else if (tcp0->flags & TCP_FLAG_ACK
 420                        && ses0->state == SNAT_SESSION_TCP_SYN_SENT)
 421                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 422               else if (tcp0->flags & TCP_FLAG_FIN
 423                        && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 424                 ses0->state = SNAT_SESSION_TCP_FIN_WAIT;
 425               else if (tcp0->flags & TCP_FLAG_ACK
 426                        && ses0->state == SNAT_SESSION_TCP_FIN_WAIT)
 427                 snat_det_ses_close (dm0, ses0);
 428               else if (tcp0->flags & TCP_FLAG_FIN
 429                        && ses0->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 430                 ses0->state = SNAT_SESSION_TCP_LAST_ACK;
 431               else if (tcp0->flags == 0
 432                        && ses0->state == SNAT_SESSION_UNKNOWN)
 433                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 434
 435               sum0 = tcp0->checksum;
 436               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 437                                      ip4_header_t,
 438                                      dst_address /* changed member */ );
 439               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 440                                      ip4_header_t /* cheat */ ,
 441                                      length /* changed member */ );
 442               mss_clamping (sm->mss_clamping, tcp0, &sum0);
 443               tcp0->checksum = ip_csum_fold (sum0);
 444             }
 445           else
 446             {
 447               ses0->state = SNAT_SESSION_UDP_ACTIVE;
 448
 449               if (PREDICT_FALSE (udp0->checksum))
 450                 {
 451                   sum0 = udp0->checksum;
 452                   sum0 =
 453                     ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 454                                     ip4_header_t,
 455                                     dst_address /* changed member */ );
 456                   sum0 =
 457                     ip_csum_update (sum0, old_port0, new_port0,
 458                                     ip4_header_t /* cheat */ ,
 459                                     length /* changed member */ );
 460                   udp0->checksum = ip_csum_fold (sum0);
 461                 }
 462             }
 463
 464           switch (ses0->state)
 465             {
 466             case SNAT_SESSION_UDP_ACTIVE:
 467               ses0->expire = now + sm->udp_timeout;
 468               break;
 469             case SNAT_SESSION_TCP_SYN_SENT:
 470             case SNAT_SESSION_TCP_FIN_WAIT:
 471             case SNAT_SESSION_TCP_CLOSE_WAIT:
 472             case SNAT_SESSION_TCP_LAST_ACK:
 473               ses0->expire = now + sm->tcp_transitory_timeout;
 474               break;
 475             case SNAT_SESSION_TCP_ESTABLISHED:
 476               ses0->expire = now + sm->tcp_established_timeout;
 477               break;
 478             }
 479
 480         trace0:
 481           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 482                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 483             {
 484               nat_det_in2out_trace_t *t =
 485                 vlib_add_trace (vm, node, b0, sizeof (*t));
 486               t->sw_if_index = sw_if_index0;
 487               t->next_index = next0;
 488               t->session_index = ~0;
 489               if (ses0)
 490                 t->session_index = ses0 - dm0->sessions;
 491             }
 492
 493           pkts_processed += next0 != NAT_DET_IN2OUT_NEXT_DROP;
 494
 495           ip1 = vlib_buffer_get_current (b1);
 496           udp1 = ip4_next_header (ip1);
 497           tcp1 = (tcp_header_t *) udp1;
 498
 499           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 500
 501           if (PREDICT_FALSE (ip1->ttl == 1))
 502             {
 503               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 504               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 505                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 506                                            0);
 507               next1 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 508               goto trace1;
 509             }
 510
 511           proto1 = ip_proto_to_nat_proto (ip1->protocol);
 512
 513           if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 514             {
 515               rx_fib_index1 =
 516                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 517               icmp1 = (icmp46_header_t *) udp1;
 518
 519               next1 = icmp_in2out (sm, b1, ip1, icmp1, sw_if_index1,
 520                                    rx_fib_index1, node, next1, thread_index,
 521                                    &ses1, &dm1);
 522               goto trace1;
 523             }
 524
 525           dm1 = snat_det_map_by_user (sm, &ip1->src_address);
 526           if (PREDICT_FALSE (!dm1))
 527             {
 528               nat_log_info ("no match for internal host %U",
 529                             format_ip4_address, &ip0->src_address);
 530               next1 = NAT_DET_IN2OUT_NEXT_DROP;
 531               b1->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 532               goto trace1;
 533             }
 534
 535           snat_det_forward (dm1, &ip1->src_address, &new_addr1, &lo_port1);
 536
 537           key1.ext_host_addr = ip1->dst_address;
 538           key1.ext_host_port = tcp1->dst;
 539
 540           ses1 =
 541             snat_det_find_ses_by_in (dm1, &ip1->src_address, tcp1->src, key1);
 542           if (PREDICT_FALSE (!ses1))
 543             {
 544               for (i1 = 0; i1 < dm1->ports_per_host; i1++)
 545                 {
 546                   key1.out_port = clib_host_to_net_u16 (lo_port1 +
 547                                                         ((i1 +
 548                                                           clib_net_to_host_u16
 549                                                           (tcp1->src)) %
 550                                                          dm1->
 551                                                          ports_per_host));
 552
 553                   if (snat_det_get_ses_by_out
 554                       (dm1, &ip1->src_address, key1.as_u64))
 555                     continue;
 556
 557                   ses1 =
 558                     snat_det_ses_create (thread_index, dm1, &ip1->src_address,
 559                                          tcp1->src, &key1);
 560                   break;
 561                 }
 562               if (PREDICT_FALSE (!ses1))
 563                 {
 564                   /* too many sessions for user, send ICMP error packet */
 565                   vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 566                   icmp4_error_set_vnet_buffer (b1,
 567                                                ICMP4_destination_unreachable,
 568                                                ICMP4_destination_unreachable_destination_unreachable_host,
 569                                                0);
 570                   next1 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 571                   goto trace1;
 572                 }
 573             }
 574
 575           old_port1 = udp1->src_port;
 576           udp1->src_port = new_port1 = ses1->out.out_port;
 577
 578           old_addr1.as_u32 = ip1->src_address.as_u32;
 579           ip1->src_address.as_u32 = new_addr1.as_u32;
 580           vnet_buffer (b1)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 581
 582           sum1 = ip1->checksum;
 583           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 584                                  ip4_header_t,
 585                                  src_address /* changed member */ );
 586           ip1->checksum = ip_csum_fold (sum1);
 587
 588           if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
 589             {
 590               if (tcp1->flags & TCP_FLAG_SYN)
 591                 ses1->state = SNAT_SESSION_TCP_SYN_SENT;
 592               else if (tcp1->flags & TCP_FLAG_ACK
 593                        && ses1->state == SNAT_SESSION_TCP_SYN_SENT)
 594                 ses1->state = SNAT_SESSION_TCP_ESTABLISHED;
 595               else if (tcp1->flags & TCP_FLAG_FIN
 596                        && ses1->state == SNAT_SESSION_TCP_ESTABLISHED)
 597                 ses1->state = SNAT_SESSION_TCP_FIN_WAIT;
 598               else if (tcp1->flags & TCP_FLAG_ACK
 599                        && ses1->state == SNAT_SESSION_TCP_FIN_WAIT)
 600                 snat_det_ses_close (dm1, ses1);
 601               else if (tcp1->flags & TCP_FLAG_FIN
 602                        && ses1->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 603                 ses1->state = SNAT_SESSION_TCP_LAST_ACK;
 604               else if (tcp1->flags == 0
 605                        && ses1->state == SNAT_SESSION_UNKNOWN)
 606                 ses1->state = SNAT_SESSION_TCP_ESTABLISHED;
 607
 608               sum1 = tcp1->checksum;
 609               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 610                                      ip4_header_t,
 611                                      dst_address /* changed member */ );
 612               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 613                                      ip4_header_t /* cheat */ ,
 614                                      length /* changed member */ );
 615               mss_clamping (sm->mss_clamping, tcp1, &sum1);
 616               tcp1->checksum = ip_csum_fold (sum1);
 617             }
 618           else
 619             {
 620               ses1->state = SNAT_SESSION_UDP_ACTIVE;
 621
 622               if (PREDICT_FALSE (udp1->checksum))
 623                 {
 624                   sum1 = udp1->checksum;
 625                   sum1 =
 626                     ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 627                                     ip4_header_t,
 628                                     dst_address /* changed member */ );
 629                   sum1 =
 630                     ip_csum_update (sum1, old_port1, new_port1,
 631                                     ip4_header_t /* cheat */ ,
 632                                     length /* changed member */ );
 633                   udp1->checksum = ip_csum_fold (sum1);
 634                 }
 635             }
 636
 637           switch (ses1->state)
 638             {
 639             case SNAT_SESSION_UDP_ACTIVE:
 640               ses1->expire = now + sm->udp_timeout;
 641               break;
 642             case SNAT_SESSION_TCP_SYN_SENT:
 643             case SNAT_SESSION_TCP_FIN_WAIT:
 644             case SNAT_SESSION_TCP_CLOSE_WAIT:
 645             case SNAT_SESSION_TCP_LAST_ACK:
 646               ses1->expire = now + sm->tcp_transitory_timeout;
 647               break;
 648             case SNAT_SESSION_TCP_ESTABLISHED:
 649               ses1->expire = now + sm->tcp_established_timeout;
 650               break;
 651             }
 652
 653         trace1:
 654           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 655                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 656             {
 657               nat_det_in2out_trace_t *t =
 658                 vlib_add_trace (vm, node, b1, sizeof (*t));
 659               t->sw_if_index = sw_if_index1;
 660               t->next_index = next1;
 661               t->session_index = ~0;
 662               if (ses1)
 663                 t->session_index = ses1 - dm1->sessions;
 664             }
 665
 666           pkts_processed += next1 != NAT_DET_IN2OUT_NEXT_DROP;
 667
 668           /* verify speculative enqueues, maybe switch current next frame */
 669           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 670                                            to_next, n_left_to_next,
 671                                            bi0, bi1, next0, next1);
 672         }
 673
 674       while (n_left_from > 0 && n_left_to_next > 0)
 675         {
 676           u32 bi0;
 677           vlib_buffer_t *b0;
 678           u32 next0;
 679           u32 sw_if_index0;
 680           ip4_header_t *ip0;
 681           ip_csum_t sum0;
 682           ip4_address_t new_addr0, old_addr0;
 683           u16 old_port0, new_port0, lo_port0, i0;
 684           udp_header_t *udp0;
 685           tcp_header_t *tcp0;
 686           u32 proto0;
 687           snat_det_out_key_t key0;
 688           snat_det_map_t *dm0;
 689           snat_det_session_t *ses0 = 0;
 690           u32 rx_fib_index0;
 691           icmp46_header_t *icmp0;
 692
 693           /* speculatively enqueue b0 to the current next frame */
 694           bi0 = from[0];
 695           to_next[0] = bi0;
 696           from += 1;
 697           to_next += 1;
 698           n_left_from -= 1;
 699           n_left_to_next -= 1;
 700
 701           b0 = vlib_get_buffer (vm, bi0);
 702           next0 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 703
 704           ip0 = vlib_buffer_get_current (b0);
 705           udp0 = ip4_next_header (ip0);
 706           tcp0 = (tcp_header_t *) udp0;
 707
 708           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 709
 710           if (PREDICT_FALSE (ip0->ttl == 1))
 711             {
 712               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 713               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 714                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 715                                            0);
 716               next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 717               goto trace00;
 718             }
 719
 720           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 721
 722           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 723             {
 724               rx_fib_index0 =
 725                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 726               icmp0 = (icmp46_header_t *) udp0;
 727
 728               next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0,
 729                                    rx_fib_index0, node, next0, thread_index,
 730                                    &ses0, &dm0);
 731               goto trace00;
 732             }
 733
 734           dm0 = snat_det_map_by_user (sm, &ip0->src_address);
 735           if (PREDICT_FALSE (!dm0))
 736             {
 737               nat_log_info ("no match for internal host %U",
 738                             format_ip4_address, &ip0->src_address);
 739               next0 = NAT_DET_IN2OUT_NEXT_DROP;
 740               b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 741               goto trace00;
 742             }
 743
 744           snat_det_forward (dm0, &ip0->src_address, &new_addr0, &lo_port0);
 745
 746           key0.ext_host_addr = ip0->dst_address;
 747           key0.ext_host_port = tcp0->dst;
 748
 749           ses0 =
 750             snat_det_find_ses_by_in (dm0, &ip0->src_address, tcp0->src, key0);
 751           if (PREDICT_FALSE (!ses0))
 752             {
 753               for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 754                 {
 755                   key0.out_port = clib_host_to_net_u16 (lo_port0 +
 756                                                         ((i0 +
 757                                                           clib_net_to_host_u16
 758                                                           (tcp0->src)) %
 759                                                          dm0->
 760                                                          ports_per_host));
 761
 762                   if (snat_det_get_ses_by_out
 763                       (dm0, &ip0->src_address, key0.as_u64))
 764                     continue;
 765
 766                   ses0 =
 767                     snat_det_ses_create (thread_index, dm0, &ip0->src_address,
 768                                          tcp0->src, &key0);
 769                   break;
 770                 }
 771               if (PREDICT_FALSE (!ses0))
 772                 {
 773                   /* too many sessions for user, send ICMP error packet */
 774                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 775                   icmp4_error_set_vnet_buffer (b0,
 776                                                ICMP4_destination_unreachable,
 777                                                ICMP4_destination_unreachable_destination_unreachable_host,
 778                                                0);
 779                   next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 780                   goto trace00;
 781                 }
 782             }
 783
 784           old_port0 = udp0->src_port;
 785           udp0->src_port = new_port0 = ses0->out.out_port;
 786
 787           old_addr0.as_u32 = ip0->src_address.as_u32;
 788           ip0->src_address.as_u32 = new_addr0.as_u32;
 789           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 790
 791           sum0 = ip0->checksum;
 792           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 793                                  ip4_header_t,
 794                                  src_address /* changed member */ );
 795           ip0->checksum = ip_csum_fold (sum0);
 796
 797           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 798             {
 799               if (tcp0->flags & TCP_FLAG_SYN)
 800                 ses0->state = SNAT_SESSION_TCP_SYN_SENT;
 801               else if (tcp0->flags & TCP_FLAG_ACK
 802                        && ses0->state == SNAT_SESSION_TCP_SYN_SENT)
 803                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 804               else if (tcp0->flags & TCP_FLAG_FIN
 805                        && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 806                 ses0->state = SNAT_SESSION_TCP_FIN_WAIT;
 807               else if (tcp0->flags & TCP_FLAG_ACK
 808                        && ses0->state == SNAT_SESSION_TCP_FIN_WAIT)
 809                 snat_det_ses_close (dm0, ses0);
 810               else if (tcp0->flags & TCP_FLAG_FIN
 811                        && ses0->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 812                 ses0->state = SNAT_SESSION_TCP_LAST_ACK;
 813               else if (tcp0->flags == 0
 814                        && ses0->state == SNAT_SESSION_UNKNOWN)
 815                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 816
 817               sum0 = tcp0->checksum;
 818               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 819                                      ip4_header_t,
 820                                      dst_address /* changed member */ );
 821               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 822                                      ip4_header_t /* cheat */ ,
 823                                      length /* changed member */ );
 824               mss_clamping (sm->mss_clamping, tcp0, &sum0);
 825               tcp0->checksum = ip_csum_fold (sum0);
 826             }
 827           else
 828             {
 829               ses0->state = SNAT_SESSION_UDP_ACTIVE;
 830
 831               if (PREDICT_FALSE (udp0->checksum))
 832                 {
 833                   sum0 = udp0->checksum;
 834                   sum0 =
 835                     ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 836                                     ip4_header_t,
 837                                     dst_address /* changed member */ );
 838                   sum0 =
 839                     ip_csum_update (sum0, old_port0, new_port0,
 840                                     ip4_header_t /* cheat */ ,
 841                                     length /* changed member */ );
 842                   udp0->checksum = ip_csum_fold (sum0);
 843                 }
 844             }
 845
 846           switch (ses0->state)
 847             {
 848             case SNAT_SESSION_UDP_ACTIVE:
 849               ses0->expire = now + sm->udp_timeout;
 850               break;
 851             case SNAT_SESSION_TCP_SYN_SENT:
 852             case SNAT_SESSION_TCP_FIN_WAIT:
 853             case SNAT_SESSION_TCP_CLOSE_WAIT:
 854             case SNAT_SESSION_TCP_LAST_ACK:
 855               ses0->expire = now + sm->tcp_transitory_timeout;
 856               break;
 857             case SNAT_SESSION_TCP_ESTABLISHED:
 858               ses0->expire = now + sm->tcp_established_timeout;
 859               break;
 860             }
 861
 862         trace00:
 863           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 864                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 865             {
 866               nat_det_in2out_trace_t *t =
 867                 vlib_add_trace (vm, node, b0, sizeof (*t));
 868               t->sw_if_index = sw_if_index0;
 869               t->next_index = next0;
 870               t->session_index = ~0;
 871               if (ses0)
 872                 t->session_index = ses0 - dm0->sessions;
 873             }
 874
 875           pkts_processed += next0 != NAT_DET_IN2OUT_NEXT_DROP;
 876
 877           /* verify speculative enqueue, maybe switch current next frame */
 878           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 879                                            to_next, n_left_to_next,
 880                                            bi0, next0);
 881         }
 882
 883       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 884     }
 885
 886   vlib_node_increment_counter (vm, sm->det_in2out_node_index,
 887                                NAT_DET_IN2OUT_ERROR_IN2OUT_PACKETS,
 888                                pkts_processed);
 889   return frame->n_vectors;
 890 }
 891
 892 /* *INDENT-OFF* */
 893 VLIB_REGISTER_NODE (snat_det_in2out_node) = {
 894   .name = "nat44-det-in2out",
 895   .vector_size = sizeof (u32),
 896   .format_trace = format_nat_det_in2out_trace,
 897   .type = VLIB_NODE_TYPE_INTERNAL,
 898   .n_errors = ARRAY_LEN(nat_det_in2out_error_strings),
 899   .error_strings = nat_det_in2out_error_strings,
 900   .n_next_nodes = NAT_DET_IN2OUT_N_NEXT,
 901   /* edit / add dispositions here */
 902   .next_nodes = {
 903     [NAT_DET_IN2OUT_NEXT_DROP] = "error-drop",
 904     [NAT_DET_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
 905     [NAT_DET_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 906   },
 907 };
 908 /* *INDENT-ON* */
 909
 910 /*
 911  * fd.io coding-style-patch-verification: ON
 912  *
 913  * Local Variables:
 914  * eval: (c-set-style "gnu")
 915  * End:
 916  */