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 vlib_node_registration_t snat_det_in2out_node;
  67
  68 static u8 *
  69 format_nat_det_in2out_trace (u8 * s, va_list * args)
  70 {
  71   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  72   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  73   nat_det_in2out_trace_t *t = va_arg (*args, nat_det_in2out_trace_t *);
  74
  75   s = format (s, "NAT_DET_IN2OUT: sw_if_index %d, next index %d, session %d",
  76               t->sw_if_index, t->next_index, t->session_index);
  77
  78   return s;
  79 }
  80
  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[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,
 100                        u8 * p_dont_translate, 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_is_error_message (icmp0))
 126     {
 127       protocol = SNAT_PROTOCOL_ICMP;
 128       in_addr = ip0->src_address;
 129       in_port = echo0->identifier;
 130     }
 131   else
 132     {
 133       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 134       l4_header = ip4_next_header (inner_ip0);
 135       protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 136       in_addr = inner_ip0->dst_address;
 137       switch (protocol)
 138         {
 139         case SNAT_PROTOCOL_ICMP:
 140           inner_icmp0 = (icmp46_header_t *) l4_header;
 141           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 142           in_port = inner_echo0->identifier;
 143           break;
 144         case SNAT_PROTOCOL_UDP:
 145         case SNAT_PROTOCOL_TCP:
 146           in_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 147           break;
 148         default:
 149           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
 150           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 151           goto out;
 152         }
 153     }
 154
 155   dm0 = snat_det_map_by_user (sm, &in_addr);
 156   if (PREDICT_FALSE (!dm0))
 157     {
 158       nat_log_info ("no match for internal host %U",
 159                     format_ip4_address, &in_addr);
 160       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 161                                                   IP_PROTOCOL_ICMP,
 162                                                   rx_fib_index0)))
 163         {
 164           dont_translate = 1;
 165           goto out;
 166         }
 167       next0 = NAT_DET_IN2OUT_NEXT_DROP;
 168       b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 169       goto out;
 170     }
 171
 172   snat_det_forward (dm0, &in_addr, &new_addr0, &lo_port0);
 173
 174   key0.ext_host_addr = ip0->dst_address;
 175   key0.ext_host_port = 0;
 176
 177   ses0 = snat_det_find_ses_by_in (dm0, &in_addr, in_port, key0);
 178   if (PREDICT_FALSE (!ses0))
 179     {
 180       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 181                                                   IP_PROTOCOL_ICMP,
 182                                                   rx_fib_index0)))
 183         {
 184           dont_translate = 1;
 185           goto out;
 186         }
 187       if (icmp0->type != ICMP4_echo_request)
 188         {
 189           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_BAD_ICMP_TYPE];
 190           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 191           goto out;
 192         }
 193       for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 194         {
 195           key0.out_port = clib_host_to_net_u16 (lo_port0 +
 196                                                 ((i0 +
 197                                                   clib_net_to_host_u16
 198                                                   (echo0->identifier)) %
 199                                                  dm0->ports_per_host));
 200
 201           if (snat_det_get_ses_by_out (dm0, &in_addr, key0.as_u64))
 202             continue;
 203
 204           ses0 =
 205             snat_det_ses_create (thread_index, dm0,
 206                                  &in_addr, echo0->identifier, &key0);
 207           break;
 208         }
 209       if (PREDICT_FALSE (!ses0))
 210         {
 211           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 212           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_OUT_OF_PORTS];
 213           goto out;
 214         }
 215     }
 216
 217   if (PREDICT_FALSE (icmp0->type != ICMP4_echo_request &&
 218                      !icmp_is_error_message (icmp0)))
 219     {
 220       b0->error = node->errors[NAT_DET_IN2OUT_ERROR_BAD_ICMP_TYPE];
 221       next0 = NAT_DET_IN2OUT_NEXT_DROP;
 222       goto out;
 223     }
 224
 225   u32 now = (u32) vlib_time_now (sm->vlib_main);
 226
 227   ses0->state = SNAT_SESSION_ICMP_ACTIVE;
 228   ses0->expire = now + sm->icmp_timeout;
 229
 230 out:
 231   *p_proto = protocol;
 232   if (ses0)
 233     {
 234       p_value->addr = new_addr0;
 235       p_value->fib_index = sm->outside_fib_index;
 236       p_value->port = ses0->out.out_port;
 237     }
 238   *p_dont_translate = dont_translate;
 239   if (d)
 240     *(snat_det_session_t **) d = ses0;
 241   if (e)
 242     *(snat_det_map_t **) e = dm0;
 243   return next0;
 244 }
 245
 246 static uword
 247 snat_det_in2out_node_fn (vlib_main_t * vm,
 248                          vlib_node_runtime_t * node, 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           new_port0 = ses0->out.out_port;
 396
 397           old_addr0.as_u32 = ip0->src_address.as_u32;
 398           ip0->src_address.as_u32 = new_addr0.as_u32;
 399           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 400
 401           sum0 = ip0->checksum;
 402           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 403                                  ip4_header_t,
 404                                  src_address /* changed member */ );
 405           ip0->checksum = ip_csum_fold (sum0);
 406
 407           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 408             {
 409               if (tcp0->flags & TCP_FLAG_SYN)
 410                 ses0->state = SNAT_SESSION_TCP_SYN_SENT;
 411               else if (tcp0->flags & TCP_FLAG_ACK
 412                        && ses0->state == SNAT_SESSION_TCP_SYN_SENT)
 413                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 414               else if (tcp0->flags & TCP_FLAG_FIN
 415                        && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 416                 ses0->state = SNAT_SESSION_TCP_FIN_WAIT;
 417               else if (tcp0->flags & TCP_FLAG_ACK
 418                        && ses0->state == SNAT_SESSION_TCP_FIN_WAIT)
 419                 snat_det_ses_close (dm0, ses0);
 420               else if (tcp0->flags & TCP_FLAG_FIN
 421                        && ses0->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 422                 ses0->state = SNAT_SESSION_TCP_LAST_ACK;
 423               else if (tcp0->flags == 0
 424                        && ses0->state == SNAT_SESSION_UNKNOWN)
 425                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 426
 427               old_port0 = tcp0->src;
 428               tcp0->src = new_port0;
 429
 430               sum0 = tcp0->checksum;
 431               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 432                                      ip4_header_t,
 433                                      dst_address /* changed member */ );
 434               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 435                                      ip4_header_t /* cheat */ ,
 436                                      length /* changed member */ );
 437               mss_clamping (sm, tcp0, &sum0);
 438               tcp0->checksum = ip_csum_fold (sum0);
 439             }
 440           else
 441             {
 442               ses0->state = SNAT_SESSION_UDP_ACTIVE;
 443               old_port0 = udp0->src_port;
 444               udp0->src_port = new_port0;
 445               udp0->checksum = 0;
 446             }
 447
 448           switch (ses0->state)
 449             {
 450             case SNAT_SESSION_UDP_ACTIVE:
 451               ses0->expire = now + sm->udp_timeout;
 452               break;
 453             case SNAT_SESSION_TCP_SYN_SENT:
 454             case SNAT_SESSION_TCP_FIN_WAIT:
 455             case SNAT_SESSION_TCP_CLOSE_WAIT:
 456             case SNAT_SESSION_TCP_LAST_ACK:
 457               ses0->expire = now + sm->tcp_transitory_timeout;
 458               break;
 459             case SNAT_SESSION_TCP_ESTABLISHED:
 460               ses0->expire = now + sm->tcp_established_timeout;
 461               break;
 462             }
 463
 464         trace0:
 465           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 466                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 467             {
 468               nat_det_in2out_trace_t *t =
 469                 vlib_add_trace (vm, node, b0, sizeof (*t));
 470               t->sw_if_index = sw_if_index0;
 471               t->next_index = next0;
 472               t->session_index = ~0;
 473               if (ses0)
 474                 t->session_index = ses0 - dm0->sessions;
 475             }
 476
 477           pkts_processed += next0 != NAT_DET_IN2OUT_NEXT_DROP;
 478
 479           ip1 = vlib_buffer_get_current (b1);
 480           udp1 = ip4_next_header (ip1);
 481           tcp1 = (tcp_header_t *) udp1;
 482
 483           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 484
 485           if (PREDICT_FALSE (ip1->ttl == 1))
 486             {
 487               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 488               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 489                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 490                                            0);
 491               next1 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 492               goto trace1;
 493             }
 494
 495           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 496
 497           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
 498             {
 499               rx_fib_index1 =
 500                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 501               icmp1 = (icmp46_header_t *) udp1;
 502
 503               next1 = icmp_in2out (sm, b1, ip1, icmp1, sw_if_index1,
 504                                    rx_fib_index1, node, next1, thread_index,
 505                                    &ses1, &dm1);
 506               goto trace1;
 507             }
 508
 509           dm1 = snat_det_map_by_user (sm, &ip1->src_address);
 510           if (PREDICT_FALSE (!dm1))
 511             {
 512               nat_log_info ("no match for internal host %U",
 513                             format_ip4_address, &ip0->src_address);
 514               next1 = NAT_DET_IN2OUT_NEXT_DROP;
 515               b1->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 516               goto trace1;
 517             }
 518
 519           snat_det_forward (dm1, &ip1->src_address, &new_addr1, &lo_port1);
 520
 521           key1.ext_host_addr = ip1->dst_address;
 522           key1.ext_host_port = tcp1->dst;
 523
 524           ses1 =
 525             snat_det_find_ses_by_in (dm1, &ip1->src_address, tcp1->src, key1);
 526           if (PREDICT_FALSE (!ses1))
 527             {
 528               for (i1 = 0; i1 < dm1->ports_per_host; i1++)
 529                 {
 530                   key1.out_port = clib_host_to_net_u16 (lo_port1 +
 531                                                         ((i1 +
 532                                                           clib_net_to_host_u16
 533                                                           (tcp1->src)) %
 534                                                          dm1->
 535                                                          ports_per_host));
 536
 537                   if (snat_det_get_ses_by_out
 538                       (dm1, &ip1->src_address, key1.as_u64))
 539                     continue;
 540
 541                   ses1 =
 542                     snat_det_ses_create (thread_index, dm1, &ip1->src_address,
 543                                          tcp1->src, &key1);
 544                   break;
 545                 }
 546               if (PREDICT_FALSE (!ses1))
 547                 {
 548                   /* too many sessions for user, send ICMP error packet */
 549                   vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 550                   icmp4_error_set_vnet_buffer (b1,
 551                                                ICMP4_destination_unreachable,
 552                                                ICMP4_destination_unreachable_destination_unreachable_host,
 553                                                0);
 554                   next1 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 555                   goto trace1;
 556                 }
 557             }
 558
 559           new_port1 = ses1->out.out_port;
 560
 561           old_addr1.as_u32 = ip1->src_address.as_u32;
 562           ip1->src_address.as_u32 = new_addr1.as_u32;
 563           vnet_buffer (b1)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 564
 565           sum1 = ip1->checksum;
 566           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 567                                  ip4_header_t,
 568                                  src_address /* changed member */ );
 569           ip1->checksum = ip_csum_fold (sum1);
 570
 571           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
 572             {
 573               if (tcp1->flags & TCP_FLAG_SYN)
 574                 ses1->state = SNAT_SESSION_TCP_SYN_SENT;
 575               else if (tcp1->flags & TCP_FLAG_ACK
 576                        && ses1->state == SNAT_SESSION_TCP_SYN_SENT)
 577                 ses1->state = SNAT_SESSION_TCP_ESTABLISHED;
 578               else if (tcp1->flags & TCP_FLAG_FIN
 579                        && ses1->state == SNAT_SESSION_TCP_ESTABLISHED)
 580                 ses1->state = SNAT_SESSION_TCP_FIN_WAIT;
 581               else if (tcp1->flags & TCP_FLAG_ACK
 582                        && ses1->state == SNAT_SESSION_TCP_FIN_WAIT)
 583                 snat_det_ses_close (dm1, ses1);
 584               else if (tcp1->flags & TCP_FLAG_FIN
 585                        && ses1->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 586                 ses1->state = SNAT_SESSION_TCP_LAST_ACK;
 587               else if (tcp1->flags == 0
 588                        && ses1->state == SNAT_SESSION_UNKNOWN)
 589                 ses1->state = SNAT_SESSION_TCP_ESTABLISHED;
 590
 591               old_port1 = tcp1->src;
 592               tcp1->src = new_port1;
 593
 594               sum1 = tcp1->checksum;
 595               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 596                                      ip4_header_t,
 597                                      dst_address /* changed member */ );
 598               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 599                                      ip4_header_t /* cheat */ ,
 600                                      length /* changed member */ );
 601               mss_clamping (sm, tcp1, &sum1);
 602               tcp1->checksum = ip_csum_fold (sum1);
 603             }
 604           else
 605             {
 606               ses1->state = SNAT_SESSION_UDP_ACTIVE;
 607               old_port1 = udp1->src_port;
 608               udp1->src_port = new_port1;
 609               udp1->checksum = 0;
 610             }
 611
 612           switch (ses1->state)
 613             {
 614             case SNAT_SESSION_UDP_ACTIVE:
 615               ses1->expire = now + sm->udp_timeout;
 616               break;
 617             case SNAT_SESSION_TCP_SYN_SENT:
 618             case SNAT_SESSION_TCP_FIN_WAIT:
 619             case SNAT_SESSION_TCP_CLOSE_WAIT:
 620             case SNAT_SESSION_TCP_LAST_ACK:
 621               ses1->expire = now + sm->tcp_transitory_timeout;
 622               break;
 623             case SNAT_SESSION_TCP_ESTABLISHED:
 624               ses1->expire = now + sm->tcp_established_timeout;
 625               break;
 626             }
 627
 628         trace1:
 629           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 630                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 631             {
 632               nat_det_in2out_trace_t *t =
 633                 vlib_add_trace (vm, node, b1, sizeof (*t));
 634               t->sw_if_index = sw_if_index1;
 635               t->next_index = next1;
 636               t->session_index = ~0;
 637               if (ses1)
 638                 t->session_index = ses1 - dm1->sessions;
 639             }
 640
 641           pkts_processed += next1 != NAT_DET_IN2OUT_NEXT_DROP;
 642
 643           /* verify speculative enqueues, maybe switch current next frame */
 644           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 645                                            to_next, n_left_to_next,
 646                                            bi0, bi1, next0, next1);
 647         }
 648
 649       while (n_left_from > 0 && n_left_to_next > 0)
 650         {
 651           u32 bi0;
 652           vlib_buffer_t *b0;
 653           u32 next0;
 654           u32 sw_if_index0;
 655           ip4_header_t *ip0;
 656           ip_csum_t sum0;
 657           ip4_address_t new_addr0, old_addr0;
 658           u16 old_port0, new_port0, lo_port0, i0;
 659           udp_header_t *udp0;
 660           tcp_header_t *tcp0;
 661           u32 proto0;
 662           snat_det_out_key_t key0;
 663           snat_det_map_t *dm0;
 664           snat_det_session_t *ses0 = 0;
 665           u32 rx_fib_index0;
 666           icmp46_header_t *icmp0;
 667
 668           /* speculatively enqueue b0 to the current next frame */
 669           bi0 = from[0];
 670           to_next[0] = bi0;
 671           from += 1;
 672           to_next += 1;
 673           n_left_from -= 1;
 674           n_left_to_next -= 1;
 675
 676           b0 = vlib_get_buffer (vm, bi0);
 677           next0 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 678
 679           ip0 = vlib_buffer_get_current (b0);
 680           udp0 = ip4_next_header (ip0);
 681           tcp0 = (tcp_header_t *) udp0;
 682
 683           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 684
 685           if (PREDICT_FALSE (ip0->ttl == 1))
 686             {
 687               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 688               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 689                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 690                                            0);
 691               next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 692               goto trace00;
 693             }
 694
 695           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 696
 697           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 698             {
 699               rx_fib_index0 =
 700                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 701               icmp0 = (icmp46_header_t *) udp0;
 702
 703               next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0,
 704                                    rx_fib_index0, node, next0, thread_index,
 705                                    &ses0, &dm0);
 706               goto trace00;
 707             }
 708
 709           dm0 = snat_det_map_by_user (sm, &ip0->src_address);
 710           if (PREDICT_FALSE (!dm0))
 711             {
 712               nat_log_info ("no match for internal host %U",
 713                             format_ip4_address, &ip0->src_address);
 714               next0 = NAT_DET_IN2OUT_NEXT_DROP;
 715               b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 716               goto trace00;
 717             }
 718
 719           snat_det_forward (dm0, &ip0->src_address, &new_addr0, &lo_port0);
 720
 721           key0.ext_host_addr = ip0->dst_address;
 722           key0.ext_host_port = tcp0->dst;
 723
 724           ses0 =
 725             snat_det_find_ses_by_in (dm0, &ip0->src_address, tcp0->src, key0);
 726           if (PREDICT_FALSE (!ses0))
 727             {
 728               for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 729                 {
 730                   key0.out_port = clib_host_to_net_u16 (lo_port0 +
 731                                                         ((i0 +
 732                                                           clib_net_to_host_u16
 733                                                           (tcp0->src)) %
 734                                                          dm0->
 735                                                          ports_per_host));
 736
 737                   if (snat_det_get_ses_by_out
 738                       (dm0, &ip0->src_address, key0.as_u64))
 739                     continue;
 740
 741                   ses0 =
 742                     snat_det_ses_create (thread_index, dm0, &ip0->src_address,
 743                                          tcp0->src, &key0);
 744                   break;
 745                 }
 746               if (PREDICT_FALSE (!ses0))
 747                 {
 748                   /* too many sessions for user, send ICMP error packet */
 749                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 750                   icmp4_error_set_vnet_buffer (b0,
 751                                                ICMP4_destination_unreachable,
 752                                                ICMP4_destination_unreachable_destination_unreachable_host,
 753                                                0);
 754                   next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 755                   goto trace00;
 756                 }
 757             }
 758
 759           new_port0 = ses0->out.out_port;
 760
 761           old_addr0.as_u32 = ip0->src_address.as_u32;
 762           ip0->src_address.as_u32 = new_addr0.as_u32;
 763           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 764
 765           sum0 = ip0->checksum;
 766           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 767                                  ip4_header_t,
 768                                  src_address /* changed member */ );
 769           ip0->checksum = ip_csum_fold (sum0);
 770
 771           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 772             {
 773               if (tcp0->flags & TCP_FLAG_SYN)
 774                 ses0->state = SNAT_SESSION_TCP_SYN_SENT;
 775               else if (tcp0->flags & TCP_FLAG_ACK
 776                        && ses0->state == SNAT_SESSION_TCP_SYN_SENT)
 777                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 778               else if (tcp0->flags & TCP_FLAG_FIN
 779                        && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 780                 ses0->state = SNAT_SESSION_TCP_FIN_WAIT;
 781               else if (tcp0->flags & TCP_FLAG_ACK
 782                        && ses0->state == SNAT_SESSION_TCP_FIN_WAIT)
 783                 snat_det_ses_close (dm0, ses0);
 784               else if (tcp0->flags & TCP_FLAG_FIN
 785                        && ses0->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 786                 ses0->state = SNAT_SESSION_TCP_LAST_ACK;
 787               else if (tcp0->flags == 0
 788                        && ses0->state == SNAT_SESSION_UNKNOWN)
 789                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 790
 791               old_port0 = tcp0->src;
 792               tcp0->src = new_port0;
 793
 794               sum0 = tcp0->checksum;
 795               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 796                                      ip4_header_t,
 797                                      dst_address /* changed member */ );
 798               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 799                                      ip4_header_t /* cheat */ ,
 800                                      length /* changed member */ );
 801               mss_clamping (sm, tcp0, &sum0);
 802               tcp0->checksum = ip_csum_fold (sum0);
 803             }
 804           else
 805             {
 806               ses0->state = SNAT_SESSION_UDP_ACTIVE;
 807               old_port0 = udp0->src_port;
 808               udp0->src_port = new_port0;
 809               udp0->checksum = 0;
 810             }
 811
 812           switch (ses0->state)
 813             {
 814             case SNAT_SESSION_UDP_ACTIVE:
 815               ses0->expire = now + sm->udp_timeout;
 816               break;
 817             case SNAT_SESSION_TCP_SYN_SENT:
 818             case SNAT_SESSION_TCP_FIN_WAIT:
 819             case SNAT_SESSION_TCP_CLOSE_WAIT:
 820             case SNAT_SESSION_TCP_LAST_ACK:
 821               ses0->expire = now + sm->tcp_transitory_timeout;
 822               break;
 823             case SNAT_SESSION_TCP_ESTABLISHED:
 824               ses0->expire = now + sm->tcp_established_timeout;
 825               break;
 826             }
 827
 828         trace00:
 829           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 830                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 831             {
 832               nat_det_in2out_trace_t *t =
 833                 vlib_add_trace (vm, node, b0, sizeof (*t));
 834               t->sw_if_index = sw_if_index0;
 835               t->next_index = next0;
 836               t->session_index = ~0;
 837               if (ses0)
 838                 t->session_index = ses0 - dm0->sessions;
 839             }
 840
 841           pkts_processed += next0 != NAT_DET_IN2OUT_NEXT_DROP;
 842
 843           /* verify speculative enqueue, maybe switch current next frame */
 844           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 845                                            to_next, n_left_to_next,
 846                                            bi0, next0);
 847         }
 848
 849       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 850     }
 851
 852   vlib_node_increment_counter (vm, snat_det_in2out_node.index,
 853                                NAT_DET_IN2OUT_ERROR_IN2OUT_PACKETS,
 854                                pkts_processed);
 855   return frame->n_vectors;
 856 }
 857
 858 /* *INDENT-OFF* */
 859 VLIB_REGISTER_NODE (snat_det_in2out_node) = {
 860   .function = snat_det_in2out_node_fn,
 861   .name = "nat44-det-in2out",
 862   .vector_size = sizeof (u32),
 863   .format_trace = format_nat_det_in2out_trace,
 864   .type = VLIB_NODE_TYPE_INTERNAL,
 865   .n_errors = ARRAY_LEN(nat_det_in2out_error_strings),
 866   .error_strings = nat_det_in2out_error_strings,
 867   .n_next_nodes = NAT_DET_IN2OUT_N_NEXT,
 868   /* edit / add dispositions here */
 869   .next_nodes = {
 870     [NAT_DET_IN2OUT_NEXT_DROP] = "error-drop",
 871     [NAT_DET_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
 872     [NAT_DET_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 873   },
 874 };
 875 /* *INDENT-ON* */
 876
 877 VLIB_NODE_FUNCTION_MULTIARCH (snat_det_in2out_node, snat_det_in2out_node_fn);
 878
 879 /*
 880  * fd.io coding-style-patch-verification: ON
 881  *
 882  * Local Variables:
 883  * eval: (c-set-style "gnu")
 884  * End:
 885  */