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