src/plugins/nat/nat_det_in2out.c

   1 /*
   2  * Copyright (c) 2018 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 /**
  16  * @file
  17  * @brief Deterministic/CGN NAT44 inside to outside network translation
  18  */
  19
  20 #include <vlib/vlib.h>
  21 #include <vnet/vnet.h>
  22 #include <vnet/ip/ip.h>
  23 #include <vnet/fib/ip4_fib.h>
  24 #include <vppinfra/error.h>
  25 #include <vppinfra/elog.h>
  26 #include <nat/nat.h>
  27 #include <nat/nat_det.h>
  28 #include <nat/nat_inlines.h>
  29
  30 typedef struct
  31 {
  32   u32 sw_if_index;
  33   u32 next_index;
  34   u32 session_index;
  35 } nat_det_in2out_trace_t;
  36
  37 typedef enum
  38 {
  39   NAT_DET_IN2OUT_NEXT_LOOKUP,
  40   NAT_DET_IN2OUT_NEXT_DROP,
  41   NAT_DET_IN2OUT_NEXT_ICMP_ERROR,
  42   NAT_DET_IN2OUT_N_NEXT,
  43 } nat_det_in2out_next_t;
  44
  45 #define foreach_nat_det_in2out_error                    \
  46 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
  47 _(NO_TRANSLATION, "No translation")                     \
  48 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  49 _(OUT_OF_PORTS, "Out of ports")                         \
  50 _(IN2OUT_PACKETS, "Good in2out packets processed")
  51
  52 typedef enum
  53 {
  54 #define _(sym,str) NAT_DET_IN2OUT_ERROR_##sym,
  55   foreach_nat_det_in2out_error
  56 #undef _
  57     NAT_DET_IN2OUT_N_ERROR,
  58 } nat_det_in2out_error_t;
  59
  60 static char *nat_det_in2out_error_strings[] = {
  61 #define _(sym,string) string,
  62   foreach_nat_det_in2out_error
  63 #undef _
  64 };
  65
  66 static u8 *
  67 format_nat_det_in2out_trace (u8 * s, va_list * args)
  68 {
  69   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  70   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  71   nat_det_in2out_trace_t *t = va_arg (*args, nat_det_in2out_trace_t *);
  72
  73   s = format (s, "NAT_DET_IN2OUT: sw_if_index %d, next index %d, session %d",
  74               t->sw_if_index, t->next_index, t->session_index);
  75
  76   return s;
  77 }
  78
  79 #ifndef CLIB_MARCH_VARIANT
  80 /**
  81  * Get address and port values to be used for ICMP packet translation
  82  * and create session if needed
  83  *
  84  * @param[in,out] sm             NAT main
  85  * @param[in,out] node           NAT node runtime
  86  * @param[in] thread_index       thread index
  87  * @param[in,out] b0             buffer containing packet to be translated
  88  * @param[out] p_proto           protocol used for matching
  89  * @param[out] p_value           address and port after NAT translation
  90  * @param[out] p_dont_translate  if packet should not be translated
  91  * @param d                      optional parameter
  92  * @param e                      optional parameter
  93  */
  94 u32
  95 icmp_match_in2out_det (snat_main_t * sm, vlib_node_runtime_t * node,
  96                        u32 thread_index, vlib_buffer_t * b0,
  97                        ip4_header_t * ip0, u8 * p_proto,
  98                        snat_session_key_t * p_value,
  99                        u8 * p_dont_translate, void *d, void *e)
 100 {
 101   icmp46_header_t *icmp0;
 102   u32 sw_if_index0;
 103   u32 rx_fib_index0;
 104   u8 protocol;
 105   snat_det_out_key_t key0;
 106   u8 dont_translate = 0;
 107   u32 next0 = ~0;
 108   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 109   ip4_header_t *inner_ip0;
 110   void *l4_header = 0;
 111   icmp46_header_t *inner_icmp0;
 112   snat_det_map_t *dm0 = 0;
 113   ip4_address_t new_addr0;
 114   u16 lo_port0, i0;
 115   snat_det_session_t *ses0 = 0;
 116   ip4_address_t in_addr;
 117   u16 in_port;
 118
 119   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 120   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 121   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 122   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 123
 124   if (!icmp_type_is_error_message
 125       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
 126     {
 127       protocol = SNAT_PROTOCOL_ICMP;
 128       in_addr = ip0->src_address;
 129       in_port = vnet_buffer (b0)->ip.reass.l4_src_port;
 130     }
 131   else
 132     {
 133       /* if error message, then it's not fragmented and we can access it */
 134       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 135       l4_header = ip4_next_header (inner_ip0);
 136       protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 137       in_addr = inner_ip0->dst_address;
 138       switch (protocol)
 139         {
 140         case SNAT_PROTOCOL_ICMP:
 141           inner_icmp0 = (icmp46_header_t *) l4_header;
 142           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 143           in_port = inner_echo0->identifier;
 144           break;
 145         case SNAT_PROTOCOL_UDP:
 146         case SNAT_PROTOCOL_TCP:
 147           in_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 148           break;
 149         default:
 150           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
 151           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 152           goto out;
 153         }
 154     }
 155
 156   dm0 = snat_det_map_by_user (sm, &in_addr);
 157   if (PREDICT_FALSE (!dm0))
 158     {
 159       nat_log_info ("no match for internal host %U",
 160                     format_ip4_address, &in_addr);
 161       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 162                                                   IP_PROTOCOL_ICMP,
 163                                                   rx_fib_index0)))
 164         {
 165           dont_translate = 1;
 166           goto out;
 167         }
 168       next0 = NAT_DET_IN2OUT_NEXT_DROP;
 169       b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 170       goto out;
 171     }
 172
 173   snat_det_forward (dm0, &in_addr, &new_addr0, &lo_port0);
 174
 175   key0.ext_host_addr = ip0->dst_address;
 176   key0.ext_host_port = 0;
 177
 178   ses0 = snat_det_find_ses_by_in (dm0, &in_addr, in_port, key0);
 179   if (PREDICT_FALSE (!ses0))
 180     {
 181       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 182                                                   IP_PROTOCOL_ICMP,
 183                                                   rx_fib_index0)))
 184         {
 185           dont_translate = 1;
 186           goto out;
 187         }
 188       if (icmp0->type != ICMP4_echo_request)
 189         {
 190           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_BAD_ICMP_TYPE];
 191           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 192           goto out;
 193         }
 194       for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 195         {
 196           key0.out_port = clib_host_to_net_u16 (lo_port0 +
 197                                                 ((i0 +
 198                                                   clib_net_to_host_u16
 199                                                   (echo0->identifier)) %
 200                                                  dm0->ports_per_host));
 201
 202           if (snat_det_get_ses_by_out (dm0, &in_addr, key0.as_u64))
 203             continue;
 204
 205           ses0 =
 206             snat_det_ses_create (thread_index, dm0,
 207                                  &in_addr, echo0->identifier, &key0);
 208           break;
 209         }
 210       if (PREDICT_FALSE (!ses0))
 211         {
 212           next0 = NAT_DET_IN2OUT_NEXT_DROP;
 213           b0->error = node->errors[NAT_DET_IN2OUT_ERROR_OUT_OF_PORTS];
 214           goto out;
 215         }
 216     }
 217
 218   if (PREDICT_FALSE
 219       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_request
 220        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 221                                        reass.icmp_type_or_tcp_flags)))
 222     {
 223       b0->error = node->errors[NAT_DET_IN2OUT_ERROR_BAD_ICMP_TYPE];
 224       next0 = NAT_DET_IN2OUT_NEXT_DROP;
 225       goto out;
 226     }
 227
 228   u32 now = (u32) vlib_time_now (sm->vlib_main);
 229
 230   ses0->state = SNAT_SESSION_ICMP_ACTIVE;
 231   ses0->expire = now + sm->icmp_timeout;
 232
 233 out:
 234   *p_proto = protocol;
 235   if (ses0)
 236     {
 237       p_value->addr = new_addr0;
 238       p_value->fib_index = sm->outside_fib_index;
 239       p_value->port = ses0->out.out_port;
 240     }
 241   *p_dont_translate = dont_translate;
 242   if (d)
 243     *(snat_det_session_t **) d = ses0;
 244   if (e)
 245     *(snat_det_map_t **) e = dm0;
 246   return next0;
 247 }
 248 #endif
 249
 250 VLIB_NODE_FN (snat_det_in2out_node) (vlib_main_t * vm,
 251                                      vlib_node_runtime_t * node,
 252                                      vlib_frame_t * frame)
 253 {
 254   u32 n_left_from, *from, *to_next;
 255   nat_det_in2out_next_t next_index;
 256   u32 pkts_processed = 0;
 257   snat_main_t *sm = &snat_main;
 258   u32 now = (u32) vlib_time_now (vm);
 259   u32 thread_index = vm->thread_index;
 260
 261   from = vlib_frame_vector_args (frame);
 262   n_left_from = frame->n_vectors;
 263   next_index = node->cached_next_index;
 264
 265   while (n_left_from > 0)
 266     {
 267       u32 n_left_to_next;
 268
 269       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 270
 271       while (n_left_from >= 4 && n_left_to_next >= 2)
 272         {
 273           u32 bi0, bi1;
 274           vlib_buffer_t *b0, *b1;
 275           u32 next0, next1;
 276           u32 sw_if_index0, sw_if_index1;
 277           ip4_header_t *ip0, *ip1;
 278           ip_csum_t sum0, sum1;
 279           ip4_address_t new_addr0, old_addr0, new_addr1, old_addr1;
 280           u16 old_port0, new_port0, lo_port0, i0;
 281           u16 old_port1, new_port1, lo_port1, i1;
 282           udp_header_t *udp0, *udp1;
 283           tcp_header_t *tcp0, *tcp1;
 284           u32 proto0, proto1;
 285           snat_det_out_key_t key0, key1;
 286           snat_det_map_t *dm0, *dm1;
 287           snat_det_session_t *ses0 = 0, *ses1 = 0;
 288           u32 rx_fib_index0, rx_fib_index1;
 289           icmp46_header_t *icmp0, *icmp1;
 290
 291           /* Prefetch next iteration. */
 292           {
 293             vlib_buffer_t *p2, *p3;
 294
 295             p2 = vlib_get_buffer (vm, from[2]);
 296             p3 = vlib_get_buffer (vm, from[3]);
 297
 298             vlib_prefetch_buffer_header (p2, LOAD);
 299             vlib_prefetch_buffer_header (p3, LOAD);
 300
 301             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 302             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 303           }
 304
 305           /* speculatively enqueue b0 and b1 to the current next frame */
 306           to_next[0] = bi0 = from[0];
 307           to_next[1] = bi1 = from[1];
 308           from += 2;
 309           to_next += 2;
 310           n_left_from -= 2;
 311           n_left_to_next -= 2;
 312
 313           b0 = vlib_get_buffer (vm, bi0);
 314           b1 = vlib_get_buffer (vm, bi1);
 315
 316           next0 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 317           next1 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 318
 319           ip0 = vlib_buffer_get_current (b0);
 320           udp0 = ip4_next_header (ip0);
 321           tcp0 = (tcp_header_t *) udp0;
 322
 323           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 324
 325           if (PREDICT_FALSE (ip0->ttl == 1))
 326             {
 327               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 328               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 329                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 330                                            0);
 331               next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 332               goto trace0;
 333             }
 334
 335           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 336
 337           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 338             {
 339               rx_fib_index0 =
 340                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 341               icmp0 = (icmp46_header_t *) udp0;
 342
 343               next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0,
 344                                    rx_fib_index0, node, next0, thread_index,
 345                                    &ses0, &dm0);
 346               goto trace0;
 347             }
 348
 349           dm0 = snat_det_map_by_user (sm, &ip0->src_address);
 350           if (PREDICT_FALSE (!dm0))
 351             {
 352               nat_log_info ("no match for internal host %U",
 353                             format_ip4_address, &ip0->src_address);
 354               next0 = NAT_DET_IN2OUT_NEXT_DROP;
 355               b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 356               goto trace0;
 357             }
 358
 359           snat_det_forward (dm0, &ip0->src_address, &new_addr0, &lo_port0);
 360
 361           key0.ext_host_addr = ip0->dst_address;
 362           key0.ext_host_port = tcp0->dst;
 363
 364           ses0 =
 365             snat_det_find_ses_by_in (dm0, &ip0->src_address, tcp0->src, key0);
 366           if (PREDICT_FALSE (!ses0))
 367             {
 368               for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 369                 {
 370                   key0.out_port = clib_host_to_net_u16 (lo_port0 +
 371                                                         ((i0 +
 372                                                           clib_net_to_host_u16
 373                                                           (tcp0->src)) %
 374                                                          dm0->
 375                                                          ports_per_host));
 376
 377                   if (snat_det_get_ses_by_out
 378                       (dm0, &ip0->src_address, key0.as_u64))
 379                     continue;
 380
 381                   ses0 =
 382                     snat_det_ses_create (thread_index, dm0, &ip0->src_address,
 383                                          tcp0->src, &key0);
 384                   break;
 385                 }
 386               if (PREDICT_FALSE (!ses0))
 387                 {
 388                   /* too many sessions for user, send ICMP error packet */
 389                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 390                   icmp4_error_set_vnet_buffer (b0,
 391                                                ICMP4_destination_unreachable,
 392                                                ICMP4_destination_unreachable_destination_unreachable_host,
 393                                                0);
 394                   next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 395                   goto trace0;
 396                 }
 397             }
 398
 399           old_port0 = udp0->src_port;
 400           udp0->src_port = new_port0 = ses0->out.out_port;
 401
 402           old_addr0.as_u32 = ip0->src_address.as_u32;
 403           ip0->src_address.as_u32 = new_addr0.as_u32;
 404           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 405
 406           sum0 = ip0->checksum;
 407           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 408                                  ip4_header_t,
 409                                  src_address /* changed member */ );
 410           ip0->checksum = ip_csum_fold (sum0);
 411
 412           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 413             {
 414               if (tcp0->flags & TCP_FLAG_SYN)
 415                 ses0->state = SNAT_SESSION_TCP_SYN_SENT;
 416               else if (tcp0->flags & TCP_FLAG_ACK
 417                        && ses0->state == SNAT_SESSION_TCP_SYN_SENT)
 418                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 419               else if (tcp0->flags & TCP_FLAG_FIN
 420                        && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 421                 ses0->state = SNAT_SESSION_TCP_FIN_WAIT;
 422               else if (tcp0->flags & TCP_FLAG_ACK
 423                        && ses0->state == SNAT_SESSION_TCP_FIN_WAIT)
 424                 snat_det_ses_close (dm0, ses0);
 425               else if (tcp0->flags & TCP_FLAG_FIN
 426                        && ses0->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 427                 ses0->state = SNAT_SESSION_TCP_LAST_ACK;
 428               else if (tcp0->flags == 0
 429                        && ses0->state == SNAT_SESSION_UNKNOWN)
 430                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 431
 432               sum0 = tcp0->checksum;
 433               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 434                                      ip4_header_t,
 435                                      dst_address /* changed member */ );
 436               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 437                                      ip4_header_t /* cheat */ ,
 438                                      length /* changed member */ );
 439               mss_clamping (sm, tcp0, &sum0);
 440               tcp0->checksum = ip_csum_fold (sum0);
 441             }
 442           else
 443             {
 444               ses0->state = SNAT_SESSION_UDP_ACTIVE;
 445
 446               if (PREDICT_FALSE (udp0->checksum))
 447                 {
 448                   sum0 = udp0->checksum;
 449                   sum0 =
 450                     ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 451                                     ip4_header_t,
 452                                     dst_address /* changed member */ );
 453                   sum0 =
 454                     ip_csum_update (sum0, old_port0, new_port0,
 455                                     ip4_header_t /* cheat */ ,
 456                                     length /* changed member */ );
 457                   udp0->checksum = ip_csum_fold (sum0);
 458                 }
 459             }
 460
 461           switch (ses0->state)
 462             {
 463             case SNAT_SESSION_UDP_ACTIVE:
 464               ses0->expire = now + sm->udp_timeout;
 465               break;
 466             case SNAT_SESSION_TCP_SYN_SENT:
 467             case SNAT_SESSION_TCP_FIN_WAIT:
 468             case SNAT_SESSION_TCP_CLOSE_WAIT:
 469             case SNAT_SESSION_TCP_LAST_ACK:
 470               ses0->expire = now + sm->tcp_transitory_timeout;
 471               break;
 472             case SNAT_SESSION_TCP_ESTABLISHED:
 473               ses0->expire = now + sm->tcp_established_timeout;
 474               break;
 475             }
 476
 477         trace0:
 478           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 479                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 480             {
 481               nat_det_in2out_trace_t *t =
 482                 vlib_add_trace (vm, node, b0, sizeof (*t));
 483               t->sw_if_index = sw_if_index0;
 484               t->next_index = next0;
 485               t->session_index = ~0;
 486               if (ses0)
 487                 t->session_index = ses0 - dm0->sessions;
 488             }
 489
 490           pkts_processed += next0 != NAT_DET_IN2OUT_NEXT_DROP;
 491
 492           ip1 = vlib_buffer_get_current (b1);
 493           udp1 = ip4_next_header (ip1);
 494           tcp1 = (tcp_header_t *) udp1;
 495
 496           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 497
 498           if (PREDICT_FALSE (ip1->ttl == 1))
 499             {
 500               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 501               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 502                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 503                                            0);
 504               next1 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 505               goto trace1;
 506             }
 507
 508           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 509
 510           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
 511             {
 512               rx_fib_index1 =
 513                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 514               icmp1 = (icmp46_header_t *) udp1;
 515
 516               next1 = icmp_in2out (sm, b1, ip1, icmp1, sw_if_index1,
 517                                    rx_fib_index1, node, next1, thread_index,
 518                                    &ses1, &dm1);
 519               goto trace1;
 520             }
 521
 522           dm1 = snat_det_map_by_user (sm, &ip1->src_address);
 523           if (PREDICT_FALSE (!dm1))
 524             {
 525               nat_log_info ("no match for internal host %U",
 526                             format_ip4_address, &ip0->src_address);
 527               next1 = NAT_DET_IN2OUT_NEXT_DROP;
 528               b1->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 529               goto trace1;
 530             }
 531
 532           snat_det_forward (dm1, &ip1->src_address, &new_addr1, &lo_port1);
 533
 534           key1.ext_host_addr = ip1->dst_address;
 535           key1.ext_host_port = tcp1->dst;
 536
 537           ses1 =
 538             snat_det_find_ses_by_in (dm1, &ip1->src_address, tcp1->src, key1);
 539           if (PREDICT_FALSE (!ses1))
 540             {
 541               for (i1 = 0; i1 < dm1->ports_per_host; i1++)
 542                 {
 543                   key1.out_port = clib_host_to_net_u16 (lo_port1 +
 544                                                         ((i1 +
 545                                                           clib_net_to_host_u16
 546                                                           (tcp1->src)) %
 547                                                          dm1->
 548                                                          ports_per_host));
 549
 550                   if (snat_det_get_ses_by_out
 551                       (dm1, &ip1->src_address, key1.as_u64))
 552                     continue;
 553
 554                   ses1 =
 555                     snat_det_ses_create (thread_index, dm1, &ip1->src_address,
 556                                          tcp1->src, &key1);
 557                   break;
 558                 }
 559               if (PREDICT_FALSE (!ses1))
 560                 {
 561                   /* too many sessions for user, send ICMP error packet */
 562                   vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 563                   icmp4_error_set_vnet_buffer (b1,
 564                                                ICMP4_destination_unreachable,
 565                                                ICMP4_destination_unreachable_destination_unreachable_host,
 566                                                0);
 567                   next1 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 568                   goto trace1;
 569                 }
 570             }
 571
 572           old_port1 = udp1->src_port;
 573           udp1->src_port = new_port1 = ses1->out.out_port;
 574
 575           old_addr1.as_u32 = ip1->src_address.as_u32;
 576           ip1->src_address.as_u32 = new_addr1.as_u32;
 577           vnet_buffer (b1)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 578
 579           sum1 = ip1->checksum;
 580           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 581                                  ip4_header_t,
 582                                  src_address /* changed member */ );
 583           ip1->checksum = ip_csum_fold (sum1);
 584
 585           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
 586             {
 587               if (tcp1->flags & TCP_FLAG_SYN)
 588                 ses1->state = SNAT_SESSION_TCP_SYN_SENT;
 589               else if (tcp1->flags & TCP_FLAG_ACK
 590                        && ses1->state == SNAT_SESSION_TCP_SYN_SENT)
 591                 ses1->state = SNAT_SESSION_TCP_ESTABLISHED;
 592               else if (tcp1->flags & TCP_FLAG_FIN
 593                        && ses1->state == SNAT_SESSION_TCP_ESTABLISHED)
 594                 ses1->state = SNAT_SESSION_TCP_FIN_WAIT;
 595               else if (tcp1->flags & TCP_FLAG_ACK
 596                        && ses1->state == SNAT_SESSION_TCP_FIN_WAIT)
 597                 snat_det_ses_close (dm1, ses1);
 598               else if (tcp1->flags & TCP_FLAG_FIN
 599                        && ses1->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 600                 ses1->state = SNAT_SESSION_TCP_LAST_ACK;
 601               else if (tcp1->flags == 0
 602                        && ses1->state == SNAT_SESSION_UNKNOWN)
 603                 ses1->state = SNAT_SESSION_TCP_ESTABLISHED;
 604
 605               sum1 = tcp1->checksum;
 606               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 607                                      ip4_header_t,
 608                                      dst_address /* changed member */ );
 609               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 610                                      ip4_header_t /* cheat */ ,
 611                                      length /* changed member */ );
 612               mss_clamping (sm, tcp1, &sum1);
 613               tcp1->checksum = ip_csum_fold (sum1);
 614             }
 615           else
 616             {
 617               ses1->state = SNAT_SESSION_UDP_ACTIVE;
 618
 619               if (PREDICT_FALSE (udp1->checksum))
 620                 {
 621                   sum1 = udp1->checksum;
 622                   sum1 =
 623                     ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 624                                     ip4_header_t,
 625                                     dst_address /* changed member */ );
 626                   sum1 =
 627                     ip_csum_update (sum1, old_port1, new_port1,
 628                                     ip4_header_t /* cheat */ ,
 629                                     length /* changed member */ );
 630                   udp1->checksum = ip_csum_fold (sum1);
 631                 }
 632             }
 633
 634           switch (ses1->state)
 635             {
 636             case SNAT_SESSION_UDP_ACTIVE:
 637               ses1->expire = now + sm->udp_timeout;
 638               break;
 639             case SNAT_SESSION_TCP_SYN_SENT:
 640             case SNAT_SESSION_TCP_FIN_WAIT:
 641             case SNAT_SESSION_TCP_CLOSE_WAIT:
 642             case SNAT_SESSION_TCP_LAST_ACK:
 643               ses1->expire = now + sm->tcp_transitory_timeout;
 644               break;
 645             case SNAT_SESSION_TCP_ESTABLISHED:
 646               ses1->expire = now + sm->tcp_established_timeout;
 647               break;
 648             }
 649
 650         trace1:
 651           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 652                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 653             {
 654               nat_det_in2out_trace_t *t =
 655                 vlib_add_trace (vm, node, b1, sizeof (*t));
 656               t->sw_if_index = sw_if_index1;
 657               t->next_index = next1;
 658               t->session_index = ~0;
 659               if (ses1)
 660                 t->session_index = ses1 - dm1->sessions;
 661             }
 662
 663           pkts_processed += next1 != NAT_DET_IN2OUT_NEXT_DROP;
 664
 665           /* verify speculative enqueues, maybe switch current next frame */
 666           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 667                                            to_next, n_left_to_next,
 668                                            bi0, bi1, next0, next1);
 669         }
 670
 671       while (n_left_from > 0 && n_left_to_next > 0)
 672         {
 673           u32 bi0;
 674           vlib_buffer_t *b0;
 675           u32 next0;
 676           u32 sw_if_index0;
 677           ip4_header_t *ip0;
 678           ip_csum_t sum0;
 679           ip4_address_t new_addr0, old_addr0;
 680           u16 old_port0, new_port0, lo_port0, i0;
 681           udp_header_t *udp0;
 682           tcp_header_t *tcp0;
 683           u32 proto0;
 684           snat_det_out_key_t key0;
 685           snat_det_map_t *dm0;
 686           snat_det_session_t *ses0 = 0;
 687           u32 rx_fib_index0;
 688           icmp46_header_t *icmp0;
 689
 690           /* speculatively enqueue b0 to the current next frame */
 691           bi0 = from[0];
 692           to_next[0] = bi0;
 693           from += 1;
 694           to_next += 1;
 695           n_left_from -= 1;
 696           n_left_to_next -= 1;
 697
 698           b0 = vlib_get_buffer (vm, bi0);
 699           next0 = NAT_DET_IN2OUT_NEXT_LOOKUP;
 700
 701           ip0 = vlib_buffer_get_current (b0);
 702           udp0 = ip4_next_header (ip0);
 703           tcp0 = (tcp_header_t *) udp0;
 704
 705           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 706
 707           if (PREDICT_FALSE (ip0->ttl == 1))
 708             {
 709               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 710               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 711                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 712                                            0);
 713               next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 714               goto trace00;
 715             }
 716
 717           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 718
 719           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 720             {
 721               rx_fib_index0 =
 722                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 723               icmp0 = (icmp46_header_t *) udp0;
 724
 725               next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0,
 726                                    rx_fib_index0, node, next0, thread_index,
 727                                    &ses0, &dm0);
 728               goto trace00;
 729             }
 730
 731           dm0 = snat_det_map_by_user (sm, &ip0->src_address);
 732           if (PREDICT_FALSE (!dm0))
 733             {
 734               nat_log_info ("no match for internal host %U",
 735                             format_ip4_address, &ip0->src_address);
 736               next0 = NAT_DET_IN2OUT_NEXT_DROP;
 737               b0->error = node->errors[NAT_DET_IN2OUT_ERROR_NO_TRANSLATION];
 738               goto trace00;
 739             }
 740
 741           snat_det_forward (dm0, &ip0->src_address, &new_addr0, &lo_port0);
 742
 743           key0.ext_host_addr = ip0->dst_address;
 744           key0.ext_host_port = tcp0->dst;
 745
 746           ses0 =
 747             snat_det_find_ses_by_in (dm0, &ip0->src_address, tcp0->src, key0);
 748           if (PREDICT_FALSE (!ses0))
 749             {
 750               for (i0 = 0; i0 < dm0->ports_per_host; i0++)
 751                 {
 752                   key0.out_port = clib_host_to_net_u16 (lo_port0 +
 753                                                         ((i0 +
 754                                                           clib_net_to_host_u16
 755                                                           (tcp0->src)) %
 756                                                          dm0->
 757                                                          ports_per_host));
 758
 759                   if (snat_det_get_ses_by_out
 760                       (dm0, &ip0->src_address, key0.as_u64))
 761                     continue;
 762
 763                   ses0 =
 764                     snat_det_ses_create (thread_index, dm0, &ip0->src_address,
 765                                          tcp0->src, &key0);
 766                   break;
 767                 }
 768               if (PREDICT_FALSE (!ses0))
 769                 {
 770                   /* too many sessions for user, send ICMP error packet */
 771                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 772                   icmp4_error_set_vnet_buffer (b0,
 773                                                ICMP4_destination_unreachable,
 774                                                ICMP4_destination_unreachable_destination_unreachable_host,
 775                                                0);
 776                   next0 = NAT_DET_IN2OUT_NEXT_ICMP_ERROR;
 777                   goto trace00;
 778                 }
 779             }
 780
 781           old_port0 = udp0->src_port;
 782           udp0->src_port = new_port0 = ses0->out.out_port;
 783
 784           old_addr0.as_u32 = ip0->src_address.as_u32;
 785           ip0->src_address.as_u32 = new_addr0.as_u32;
 786           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
 787
 788           sum0 = ip0->checksum;
 789           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 790                                  ip4_header_t,
 791                                  src_address /* changed member */ );
 792           ip0->checksum = ip_csum_fold (sum0);
 793
 794           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 795             {
 796               if (tcp0->flags & TCP_FLAG_SYN)
 797                 ses0->state = SNAT_SESSION_TCP_SYN_SENT;
 798               else if (tcp0->flags & TCP_FLAG_ACK
 799                        && ses0->state == SNAT_SESSION_TCP_SYN_SENT)
 800                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 801               else if (tcp0->flags & TCP_FLAG_FIN
 802                        && ses0->state == SNAT_SESSION_TCP_ESTABLISHED)
 803                 ses0->state = SNAT_SESSION_TCP_FIN_WAIT;
 804               else if (tcp0->flags & TCP_FLAG_ACK
 805                        && ses0->state == SNAT_SESSION_TCP_FIN_WAIT)
 806                 snat_det_ses_close (dm0, ses0);
 807               else if (tcp0->flags & TCP_FLAG_FIN
 808                        && ses0->state == SNAT_SESSION_TCP_CLOSE_WAIT)
 809                 ses0->state = SNAT_SESSION_TCP_LAST_ACK;
 810               else if (tcp0->flags == 0
 811                        && ses0->state == SNAT_SESSION_UNKNOWN)
 812                 ses0->state = SNAT_SESSION_TCP_ESTABLISHED;
 813
 814               sum0 = tcp0->checksum;
 815               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 816                                      ip4_header_t,
 817                                      dst_address /* changed member */ );
 818               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 819                                      ip4_header_t /* cheat */ ,
 820                                      length /* changed member */ );
 821               mss_clamping (sm, tcp0, &sum0);
 822               tcp0->checksum = ip_csum_fold (sum0);
 823             }
 824           else
 825             {
 826               ses0->state = SNAT_SESSION_UDP_ACTIVE;
 827
 828               if (PREDICT_FALSE (udp0->checksum))
 829                 {
 830                   sum0 = udp0->checksum;
 831                   sum0 =
 832                     ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 833                                     ip4_header_t,
 834                                     dst_address /* changed member */ );
 835                   sum0 =
 836                     ip_csum_update (sum0, old_port0, new_port0,
 837                                     ip4_header_t /* cheat */ ,
 838                                     length /* changed member */ );
 839                   udp0->checksum = ip_csum_fold (sum0);
 840                 }
 841             }
 842
 843           switch (ses0->state)
 844             {
 845             case SNAT_SESSION_UDP_ACTIVE:
 846               ses0->expire = now + sm->udp_timeout;
 847               break;
 848             case SNAT_SESSION_TCP_SYN_SENT:
 849             case SNAT_SESSION_TCP_FIN_WAIT:
 850             case SNAT_SESSION_TCP_CLOSE_WAIT:
 851             case SNAT_SESSION_TCP_LAST_ACK:
 852               ses0->expire = now + sm->tcp_transitory_timeout;
 853               break;
 854             case SNAT_SESSION_TCP_ESTABLISHED:
 855               ses0->expire = now + sm->tcp_established_timeout;
 856               break;
 857             }
 858
 859         trace00:
 860           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 861                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 862             {
 863               nat_det_in2out_trace_t *t =
 864                 vlib_add_trace (vm, node, b0, sizeof (*t));
 865               t->sw_if_index = sw_if_index0;
 866               t->next_index = next0;
 867               t->session_index = ~0;
 868               if (ses0)
 869                 t->session_index = ses0 - dm0->sessions;
 870             }
 871
 872           pkts_processed += next0 != NAT_DET_IN2OUT_NEXT_DROP;
 873
 874           /* verify speculative enqueue, maybe switch current next frame */
 875           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 876                                            to_next, n_left_to_next,
 877                                            bi0, next0);
 878         }
 879
 880       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 881     }
 882
 883   vlib_node_increment_counter (vm, sm->det_in2out_node_index,
 884                                NAT_DET_IN2OUT_ERROR_IN2OUT_PACKETS,
 885                                pkts_processed);
 886   return frame->n_vectors;
 887 }
 888
 889 /* *INDENT-OFF* */
 890 VLIB_REGISTER_NODE (snat_det_in2out_node) = {
 891   .name = "nat44-det-in2out",
 892   .vector_size = sizeof (u32),
 893   .format_trace = format_nat_det_in2out_trace,
 894   .type = VLIB_NODE_TYPE_INTERNAL,
 895   .n_errors = ARRAY_LEN(nat_det_in2out_error_strings),
 896   .error_strings = nat_det_in2out_error_strings,
 897   .n_next_nodes = NAT_DET_IN2OUT_N_NEXT,
 898   /* edit / add dispositions here */
 899   .next_nodes = {
 900     [NAT_DET_IN2OUT_NEXT_DROP] = "error-drop",
 901     [NAT_DET_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
 902     [NAT_DET_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 903   },
 904 };
 905 /* *INDENT-ON* */
 906
 907 /*
 908  * fd.io coding-style-patch-verification: ON
 909  *
 910  * Local Variables:
 911  * eval: (c-set-style "gnu")
 912  * End:
 913  */