src/plugins/nat/det44/det44_out2in.c

   1 /*
   2  * Copyright (c) 2020 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 /**
  17  * @file
  18  * @brief Deterministic NAT (CGN) outside to inside translation
  19  */
  20
  21 #include <vlib/vlib.h>
  22 #include <vnet/vnet.h>
  23 #include <vnet/ip/ip.h>
  24 #include <vnet/fib/ip4_fib.h>
  25 #include <vppinfra/error.h>
  26 #include <vppinfra/elog.h>
  27
  28 #include <nat/det44/det44.h>
  29 #include <nat/det44/det44_inlines.h>
  30
  31 #include <nat/lib/lib.h>
  32 #include <nat/lib/inlines.h>
  33 #include <nat/lib/nat_inlines.h>
  34
  35 typedef enum
  36 {
  37   DET44_OUT2IN_NEXT_DROP,
  38   DET44_OUT2IN_NEXT_LOOKUP,
  39   DET44_OUT2IN_NEXT_ICMP_ERROR,
  40   DET44_OUT2IN_N_NEXT,
  41 } det44_out2in_next_t;
  42
  43 typedef struct
  44 {
  45   u32 sw_if_index;
  46   u32 next_index;
  47   u32 session_index;
  48 } det44_out2in_trace_t;
  49
  50 #define foreach_det44_out2in_error                 \
  51 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")    \
  52 _(NO_TRANSLATION, "No translation")                \
  53 _(BAD_ICMP_TYPE, "unsupported ICMP type")          \
  54 _(OUT2IN_PACKETS, "Good out2in packets processed")
  55
  56 typedef enum
  57 {
  58 #define _(sym,str) DET44_OUT2IN_ERROR_##sym,
  59   foreach_det44_out2in_error
  60 #undef _
  61     DET44_OUT2IN_N_ERROR,
  62 } det44_out2in_error_t;
  63
  64 static char *det44_out2in_error_strings[] = {
  65 #define _(sym,string) string,
  66   foreach_det44_out2in_error
  67 #undef _
  68 };
  69
  70 static u8 *
  71 format_det44_out2in_trace (u8 * s, va_list * args)
  72 {
  73   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  74   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  75   det44_out2in_trace_t *t = va_arg (*args, det44_out2in_trace_t *);
  76
  77   s =
  78     format (s,
  79             "DET44_OUT2IN: sw_if_index %d, next index %d, session index %d",
  80             t->sw_if_index, t->next_index, t->session_index);
  81   return s;
  82 }
  83
  84 #ifndef CLIB_MARCH_VARIANT
  85 /**
  86  * Get address and port values to be used for ICMP packet translation
  87  * and create session if needed
  88  *
  89  * @param[in,out] node           NAT node runtime
  90  * @param[in] thread_index       thread index
  91  * @param[in,out] b0             buffer containing packet to be translated
  92  * @param[in,out] ip0            ip header
  93  * @param[out] p_proto           protocol used for matching
  94  * @param[out] p_value           address and port after NAT translation
  95  * @param[out] p_dont_translate  if packet should not be translated
  96  * @param d                      optional parameter
  97  * @param e                      optional parameter
  98  */
  99 u32
 100 icmp_match_out2in_det (vlib_node_runtime_t * node,
 101                        u32 thread_index, vlib_buffer_t * b0,
 102                        ip4_header_t * ip0, ip4_address_t * addr,
 103                        u16 * port, u32 * fib_index,
 104                        nat_protocol_t * proto, void *d, void *e,
 105                        u8 * dont_translate)
 106 {
 107   det44_main_t *dm = &det44_main;
 108   icmp46_header_t *icmp0;
 109   u32 sw_if_index0;
 110   u8 protocol;
 111   snat_det_out_key_t key0;
 112   u32 next0 = ~0;
 113   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 114   ip4_header_t *inner_ip0;
 115   void *l4_header = 0;
 116   icmp46_header_t *inner_icmp0;
 117   snat_det_map_t *mp0 = 0;
 118   ip4_address_t new_addr0 = { {0} };
 119   snat_det_session_t *ses0 = 0;
 120   ip4_address_t out_addr;
 121   *dont_translate = 0;
 122
 123   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 124   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 125   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 126
 127   if (!icmp_type_is_error_message
 128       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
 129     {
 130       protocol = NAT_PROTOCOL_ICMP;
 131       key0.ext_host_addr = ip0->src_address;
 132       key0.ext_host_port = 0;
 133       key0.out_port = vnet_buffer (b0)->ip.reass.l4_src_port;
 134       out_addr = ip0->dst_address;
 135     }
 136   else
 137     {
 138       /* if error message, then it's not fragmented and we can access it */
 139       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 140       l4_header = ip4_next_header (inner_ip0);
 141       protocol = ip_proto_to_nat_proto (inner_ip0->protocol);
 142       key0.ext_host_addr = inner_ip0->dst_address;
 143       out_addr = inner_ip0->src_address;
 144       switch (protocol)
 145         {
 146         case NAT_PROTOCOL_ICMP:
 147           inner_icmp0 = (icmp46_header_t *) l4_header;
 148           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 149           key0.ext_host_port = 0;
 150           key0.out_port = inner_echo0->identifier;
 151           break;
 152         case NAT_PROTOCOL_UDP:
 153         case NAT_PROTOCOL_TCP:
 154           key0.ext_host_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 155           key0.out_port = ((tcp_udp_header_t *) l4_header)->src_port;
 156           break;
 157         default:
 158           b0->error = node->errors[DET44_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 159           next0 = DET44_OUT2IN_NEXT_DROP;
 160           goto out;
 161         }
 162     }
 163
 164   mp0 = snat_det_map_by_out (&out_addr);
 165   if (PREDICT_FALSE (!mp0))
 166     {
 167       /* Don't NAT packet aimed at the intfc address */
 168       if (PREDICT_FALSE (!det44_is_interface_addr (node, sw_if_index0,
 169                                                    ip0->dst_address.as_u32)))
 170         {
 171           *dont_translate = 1;
 172           goto out;
 173         }
 174       det44_log_info ("unknown dst address:  %U",
 175                       format_ip4_address, &ip0->dst_address);
 176       b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 177       next0 = DET44_OUT2IN_NEXT_DROP;
 178
 179       goto out;
 180     }
 181
 182   snat_det_reverse (mp0, &ip0->dst_address,
 183                     clib_net_to_host_u16 (key0.out_port), &new_addr0);
 184
 185   ses0 = snat_det_get_ses_by_out (mp0, &new_addr0, key0.as_u64);
 186   if (PREDICT_FALSE (!ses0))
 187     {
 188       /* Don't NAT packet aimed at the intfc address */
 189       if (PREDICT_FALSE (!det44_is_interface_addr (node, sw_if_index0,
 190                                                    ip0->dst_address.as_u32)))
 191         {
 192           *dont_translate = 1;
 193           goto out;
 194         }
 195       det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 196                       format_ip4_address, &key0.ext_host_addr,
 197                       clib_net_to_host_u16 (key0.ext_host_port),
 198                       format_ip4_address, &out_addr,
 199                       clib_net_to_host_u16 (key0.out_port),
 200                       format_ip4_address, &new_addr0);
 201       b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 202       next0 = DET44_OUT2IN_NEXT_DROP;
 203       goto out;
 204     }
 205
 206   if (PREDICT_FALSE
 207       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
 208        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 209                                        reass.icmp_type_or_tcp_flags)))
 210     {
 211       b0->error = node->errors[DET44_OUT2IN_ERROR_BAD_ICMP_TYPE];
 212       next0 = DET44_OUT2IN_NEXT_DROP;
 213       goto out;
 214     }
 215
 216   goto out;
 217
 218 out:
 219   *proto = protocol;
 220   if (ses0)
 221     {
 222       *addr = new_addr0;
 223       *fib_index = dm->inside_fib_index;
 224       *port = ses0->in_port;
 225     }
 226   if (d)
 227     *(snat_det_session_t **) d = ses0;
 228   if (e)
 229     *(snat_det_map_t **) e = mp0;
 230   return next0;
 231 }
 232 #endif
 233
 234 #ifndef CLIB_MARCH_VARIANT
 235 u32
 236 det44_icmp_out2in (vlib_buffer_t * b0,
 237                    ip4_header_t * ip0,
 238                    icmp46_header_t * icmp0,
 239                    u32 sw_if_index0,
 240                    u32 rx_fib_index0,
 241                    vlib_node_runtime_t * node,
 242                    u32 next0, u32 thread_index, void *d, void *e)
 243 {
 244   vlib_main_t *vm = vlib_get_main ();
 245   u32 new_addr0, old_addr0, next0_tmp, fib_index;
 246   u16 old_id0, new_id0, port, checksum0;
 247   icmp_echo_header_t *echo0, *inner_echo0;
 248   icmp46_header_t *inner_icmp0;
 249   ip4_header_t *inner_ip0;
 250   ip4_address_t addr;
 251   void *l4_header;
 252   u8 dont_translate;
 253   ip_csum_t sum0;
 254   nat_protocol_t proto;
 255
 256   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 257   next0_tmp = icmp_match_out2in_det (node, thread_index, b0, ip0,
 258                                      &addr, &port, &fib_index, &proto,
 259                                      d, e, &dont_translate);
 260   if (next0_tmp != ~0)
 261     next0 = next0_tmp;
 262   if (next0 == DET44_OUT2IN_NEXT_DROP || dont_translate)
 263     goto out;
 264
 265   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 266     {
 267       sum0 =
 268         ip_incremental_checksum_buffer (vm, b0,
 269                                         (u8 *) icmp0 -
 270                                         (u8 *) vlib_buffer_get_current (b0),
 271                                         ntohs (ip0->length) -
 272                                         ip4_header_bytes (ip0), 0);
 273       checksum0 = ~ip_csum_fold (sum0);
 274       if (checksum0 != 0 && checksum0 != 0xffff)
 275         {
 276           next0 = DET44_OUT2IN_NEXT_DROP;
 277           goto out;
 278         }
 279     }
 280
 281   old_addr0 = ip0->dst_address.as_u32;
 282   new_addr0 = ip0->dst_address.as_u32 = addr.as_u32;
 283   vnet_buffer (b0)->sw_if_index[VLIB_TX] = fib_index;
 284
 285   sum0 = ip0->checksum;
 286   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 287                          dst_address /* changed member */ );
 288   ip0->checksum = ip_csum_fold (sum0);
 289
 290
 291   if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 292     {
 293       if (icmp0->checksum == 0)
 294         icmp0->checksum = 0xffff;
 295
 296       if (!icmp_type_is_error_message (icmp0->type))
 297         {
 298           new_id0 = port;
 299           if (PREDICT_FALSE (new_id0 != echo0->identifier))
 300             {
 301               old_id0 = echo0->identifier;
 302               new_id0 = port;
 303               echo0->identifier = new_id0;
 304
 305               sum0 = icmp0->checksum;
 306               sum0 =
 307                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 308                                 identifier /* changed member */ );
 309               icmp0->checksum = ip_csum_fold (sum0);
 310             }
 311         }
 312       else
 313         {
 314           inner_ip0 = (ip4_header_t *) (echo0 + 1);
 315           l4_header = ip4_next_header (inner_ip0);
 316
 317           if (!ip4_header_checksum_is_valid (inner_ip0))
 318             {
 319               next0 = DET44_OUT2IN_NEXT_DROP;
 320               goto out;
 321             }
 322
 323           old_addr0 = inner_ip0->src_address.as_u32;
 324           inner_ip0->src_address = addr;
 325           new_addr0 = inner_ip0->src_address.as_u32;
 326
 327           sum0 = icmp0->checksum;
 328           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 329                                  src_address /* changed member */ );
 330           icmp0->checksum = ip_csum_fold (sum0);
 331
 332           switch (proto)
 333             {
 334             case NAT_PROTOCOL_ICMP:
 335               inner_icmp0 = (icmp46_header_t *) l4_header;
 336               inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 337
 338               old_id0 = inner_echo0->identifier;
 339               new_id0 = port;
 340               inner_echo0->identifier = new_id0;
 341
 342               sum0 = icmp0->checksum;
 343               sum0 =
 344                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 345                                 identifier);
 346               icmp0->checksum = ip_csum_fold (sum0);
 347               break;
 348             case NAT_PROTOCOL_UDP:
 349             case NAT_PROTOCOL_TCP:
 350               old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 351               new_id0 = port;
 352               ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 353
 354               sum0 = icmp0->checksum;
 355               sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 356                                      src_port);
 357               icmp0->checksum = ip_csum_fold (sum0);
 358               break;
 359             default:
 360               ASSERT (0);
 361             }
 362         }
 363     }
 364
 365 out:
 366   return next0;
 367 }
 368 #endif
 369
 370 VLIB_NODE_FN (det44_out2in_node) (vlib_main_t * vm,
 371                                   vlib_node_runtime_t * node,
 372                                   vlib_frame_t * frame)
 373 {
 374   u32 n_left_from, *from;
 375   u32 pkts_processed = 0;
 376   det44_main_t *dm = &det44_main;
 377   u32 thread_index = vm->thread_index;
 378
 379   from = vlib_frame_vector_args (frame);
 380   n_left_from = frame->n_vectors;
 381
 382   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
 383   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 384   vlib_get_buffers (vm, from, b, n_left_from);
 385
 386   while (n_left_from >= 2)
 387     {
 388       vlib_buffer_t *b0, *b1;
 389       u32 next0 = DET44_OUT2IN_NEXT_LOOKUP;
 390       u32 next1 = DET44_OUT2IN_NEXT_LOOKUP;
 391       u32 sw_if_index0, sw_if_index1;
 392       ip4_header_t *ip0, *ip1;
 393       ip_csum_t sum0, sum1;
 394       ip4_address_t new_addr0, old_addr0, new_addr1, old_addr1;
 395       u16 new_port0, old_port0, old_port1, new_port1;
 396       udp_header_t *udp0, *udp1;
 397       tcp_header_t *tcp0, *tcp1;
 398       u32 proto0, proto1;
 399       snat_det_out_key_t key0, key1;
 400       snat_det_map_t *mp0, *mp1;
 401       snat_det_session_t *ses0 = 0, *ses1 = 0;
 402       u32 rx_fib_index0, rx_fib_index1;
 403       icmp46_header_t *icmp0, *icmp1;
 404
 405       b0 = *b;
 406       b++;
 407       b1 = *b;
 408       b++;
 409
 410       /* Prefetch next iteration. */
 411       if (PREDICT_TRUE (n_left_from >= 4))
 412         {
 413           vlib_buffer_t *p2, *p3;
 414
 415           p2 = *b;
 416           p3 = *(b + 1);
 417
 418           vlib_prefetch_buffer_header (p2, LOAD);
 419           vlib_prefetch_buffer_header (p3, LOAD);
 420
 421           clib_prefetch_load (p2->data);
 422           clib_prefetch_load (p3->data);
 423         }
 424
 425
 426       ip0 = vlib_buffer_get_current (b0);
 427       udp0 = ip4_next_header (ip0);
 428       tcp0 = (tcp_header_t *) udp0;
 429
 430       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 431
 432       if (PREDICT_FALSE (ip0->ttl == 1))
 433         {
 434           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 435           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 436                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 437                                        0);
 438           next0 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 439           goto trace0;
 440         }
 441
 442       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 443
 444       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 445         {
 446           rx_fib_index0 =
 447             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 448           icmp0 = (icmp46_header_t *) udp0;
 449
 450           next0 = det44_icmp_out2in (b0, ip0, icmp0, sw_if_index0,
 451                                      rx_fib_index0, node, next0,
 452                                      thread_index, &ses0, &mp0);
 453           goto trace0;
 454         }
 455
 456       key0.ext_host_addr = ip0->src_address;
 457       key0.ext_host_port = tcp0->src;
 458       key0.out_port = tcp0->dst;
 459
 460       mp0 = snat_det_map_by_out (&ip0->dst_address);
 461       if (PREDICT_FALSE (!mp0))
 462         {
 463           det44_log_info ("unknown dst address:  %U",
 464                           format_ip4_address, &ip0->dst_address);
 465           next0 = DET44_OUT2IN_NEXT_DROP;
 466           b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 467           goto trace0;
 468         }
 469
 470       snat_det_reverse (mp0, &ip0->dst_address,
 471                         clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 472
 473       ses0 = snat_det_get_ses_by_out (mp0, &new_addr0, key0.as_u64);
 474       if (PREDICT_FALSE (!ses0))
 475         {
 476           det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 477                           format_ip4_address, &ip0->src_address,
 478                           clib_net_to_host_u16 (tcp0->src),
 479                           format_ip4_address, &ip0->dst_address,
 480                           clib_net_to_host_u16 (tcp0->dst),
 481                           format_ip4_address, &new_addr0);
 482           next0 = DET44_OUT2IN_NEXT_DROP;
 483           b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 484           goto trace0;
 485         }
 486       old_port0 = udp0->dst_port;
 487       udp0->dst_port = new_port0 = ses0->in_port;
 488
 489       old_addr0 = ip0->dst_address;
 490       ip0->dst_address = new_addr0;
 491       vnet_buffer (b0)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 492
 493       sum0 = ip0->checksum;
 494       sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 495                              ip4_header_t, dst_address /* changed member */ );
 496       ip0->checksum = ip_csum_fold (sum0);
 497
 498       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 499         {
 500           if (tcp0->flags & TCP_FLAG_FIN
 501               && ses0->state == DET44_SESSION_TCP_ESTABLISHED)
 502             ses0->state = DET44_SESSION_TCP_CLOSE_WAIT;
 503           else if (tcp0->flags & TCP_FLAG_ACK
 504                    && ses0->state == DET44_SESSION_TCP_LAST_ACK)
 505             snat_det_ses_close (mp0, ses0);
 506
 507           sum0 = tcp0->checksum;
 508           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 509                                  ip4_header_t,
 510                                  dst_address /* changed member */ );
 511           sum0 = ip_csum_update (sum0, old_port0, new_port0,
 512                                  ip4_header_t /* cheat */ ,
 513                                  length /* changed member */ );
 514           tcp0->checksum = ip_csum_fold (sum0);
 515         }
 516       else if (udp0->checksum)
 517         {
 518           sum0 = udp0->checksum;
 519           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 520                                  ip4_header_t,
 521                                  dst_address /* changed member */ );
 522           sum0 = ip_csum_update (sum0, old_port0, new_port0,
 523                                  ip4_header_t /* cheat */ ,
 524                                  length /* changed member */ );
 525           udp0->checksum = ip_csum_fold (sum0);
 526         }
 527
 528     trace0:
 529
 530       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 531                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 532         {
 533           det44_out2in_trace_t *t =
 534             vlib_add_trace (vm, node, b0, sizeof (*t));
 535           t->sw_if_index = sw_if_index0;
 536           t->next_index = next0;
 537           t->session_index = ~0;
 538           if (ses0)
 539             t->session_index = ses0 - mp0->sessions;
 540         }
 541
 542       pkts_processed += next0 != DET44_OUT2IN_NEXT_DROP;
 543
 544       ip1 = vlib_buffer_get_current (b1);
 545       udp1 = ip4_next_header (ip1);
 546       tcp1 = (tcp_header_t *) udp1;
 547
 548       sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 549
 550       if (PREDICT_FALSE (ip1->ttl == 1))
 551         {
 552           vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 553           icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 554                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 555                                        0);
 556           next1 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 557           goto trace1;
 558         }
 559
 560       proto1 = ip_proto_to_nat_proto (ip1->protocol);
 561
 562       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 563         {
 564           rx_fib_index1 =
 565             ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 566           icmp1 = (icmp46_header_t *) udp1;
 567
 568           next1 = det44_icmp_out2in (b1, ip1, icmp1, sw_if_index1,
 569                                      rx_fib_index1, node, next1,
 570                                      thread_index, &ses1, &mp1);
 571           goto trace1;
 572         }
 573
 574       key1.ext_host_addr = ip1->src_address;
 575       key1.ext_host_port = tcp1->src;
 576       key1.out_port = tcp1->dst;
 577
 578       mp1 = snat_det_map_by_out (&ip1->dst_address);
 579       if (PREDICT_FALSE (!mp1))
 580         {
 581           det44_log_info ("unknown dst address:  %U",
 582                           format_ip4_address, &ip1->dst_address);
 583           next1 = DET44_OUT2IN_NEXT_DROP;
 584           b1->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 585           goto trace1;
 586         }
 587
 588       snat_det_reverse (mp1, &ip1->dst_address,
 589                         clib_net_to_host_u16 (tcp1->dst), &new_addr1);
 590
 591       ses1 = snat_det_get_ses_by_out (mp1, &new_addr1, key1.as_u64);
 592       if (PREDICT_FALSE (!ses1))
 593         {
 594           det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 595                           format_ip4_address, &ip1->src_address,
 596                           clib_net_to_host_u16 (tcp1->src),
 597                           format_ip4_address, &ip1->dst_address,
 598                           clib_net_to_host_u16 (tcp1->dst),
 599                           format_ip4_address, &new_addr1);
 600           next1 = DET44_OUT2IN_NEXT_DROP;
 601           b1->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 602           goto trace1;
 603         }
 604       old_port1 = udp1->dst_port;
 605       udp1->dst_port = new_port1 = ses1->in_port;
 606
 607       old_addr1 = ip1->dst_address;
 608       ip1->dst_address = new_addr1;
 609       vnet_buffer (b1)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 610
 611       sum1 = ip1->checksum;
 612       sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 613                              ip4_header_t, dst_address /* changed member */ );
 614       ip1->checksum = ip_csum_fold (sum1);
 615
 616       if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
 617         {
 618           if (tcp1->flags & TCP_FLAG_FIN
 619               && ses1->state == DET44_SESSION_TCP_ESTABLISHED)
 620             ses1->state = DET44_SESSION_TCP_CLOSE_WAIT;
 621           else if (tcp1->flags & TCP_FLAG_ACK
 622                    && ses1->state == DET44_SESSION_TCP_LAST_ACK)
 623             snat_det_ses_close (mp1, ses1);
 624
 625           sum1 = tcp1->checksum;
 626           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 627                                  ip4_header_t,
 628                                  dst_address /* changed member */ );
 629           sum1 = ip_csum_update (sum1, old_port1, new_port1,
 630                                  ip4_header_t /* cheat */ ,
 631                                  length /* changed member */ );
 632           tcp1->checksum = ip_csum_fold (sum1);
 633         }
 634       else if (udp1->checksum)
 635         {
 636           sum1 = udp1->checksum;
 637           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 638                                  ip4_header_t,
 639                                  dst_address /* changed member */ );
 640           sum1 = ip_csum_update (sum1, old_port1, new_port1,
 641                                  ip4_header_t /* cheat */ ,
 642                                  length /* changed member */ );
 643           udp1->checksum = ip_csum_fold (sum1);
 644         }
 645
 646     trace1:
 647
 648       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 649                          && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 650         {
 651           det44_out2in_trace_t *t =
 652             vlib_add_trace (vm, node, b1, sizeof (*t));
 653           t->sw_if_index = sw_if_index1;
 654           t->next_index = next1;
 655           t->session_index = ~0;
 656           if (ses1)
 657             t->session_index = ses1 - mp1->sessions;
 658         }
 659
 660       pkts_processed += next1 != DET44_OUT2IN_NEXT_DROP;
 661
 662       n_left_from -= 2;
 663       next[0] = next0;
 664       next[1] = next1;
 665       next += 2;
 666     }
 667
 668   while (n_left_from > 0)
 669     {
 670       vlib_buffer_t *b0;
 671       u32 next0 = DET44_OUT2IN_NEXT_LOOKUP;
 672       u32 sw_if_index0;
 673       ip4_header_t *ip0;
 674       ip_csum_t sum0;
 675       ip4_address_t new_addr0, old_addr0;
 676       u16 new_port0, old_port0;
 677       udp_header_t *udp0;
 678       tcp_header_t *tcp0;
 679       u32 proto0;
 680       snat_det_out_key_t key0;
 681       snat_det_map_t *mp0;
 682       snat_det_session_t *ses0 = 0;
 683       u32 rx_fib_index0;
 684       icmp46_header_t *icmp0;
 685
 686       b0 = *b;
 687       b++;
 688
 689       ip0 = vlib_buffer_get_current (b0);
 690       udp0 = ip4_next_header (ip0);
 691       tcp0 = (tcp_header_t *) udp0;
 692
 693       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 694
 695       if (PREDICT_FALSE (ip0->ttl == 1))
 696         {
 697           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 698           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 699                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 700                                        0);
 701           next0 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 702           goto trace00;
 703         }
 704
 705       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 706
 707       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 708         {
 709           rx_fib_index0 =
 710             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 711           icmp0 = (icmp46_header_t *) udp0;
 712
 713           next0 = det44_icmp_out2in (b0, ip0, icmp0, sw_if_index0,
 714                                      rx_fib_index0, node, next0,
 715                                      thread_index, &ses0, &mp0);
 716           goto trace00;
 717         }
 718
 719       key0.ext_host_addr = ip0->src_address;
 720       key0.ext_host_port = tcp0->src;
 721       key0.out_port = tcp0->dst;
 722
 723       mp0 = snat_det_map_by_out (&ip0->dst_address);
 724       if (PREDICT_FALSE (!mp0))
 725         {
 726           det44_log_info ("unknown dst address:  %U",
 727                           format_ip4_address, &ip0->dst_address);
 728           next0 = DET44_OUT2IN_NEXT_DROP;
 729           b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 730           goto trace00;
 731         }
 732
 733       snat_det_reverse (mp0, &ip0->dst_address,
 734                         clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 735
 736       ses0 = snat_det_get_ses_by_out (mp0, &new_addr0, key0.as_u64);
 737       if (PREDICT_FALSE (!ses0))
 738         {
 739           det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 740                           format_ip4_address, &ip0->src_address,
 741                           clib_net_to_host_u16 (tcp0->src),
 742                           format_ip4_address, &ip0->dst_address,
 743                           clib_net_to_host_u16 (tcp0->dst),
 744                           format_ip4_address, &new_addr0);
 745           next0 = DET44_OUT2IN_NEXT_DROP;
 746           b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 747           goto trace00;
 748         }
 749       old_port0 = udp0->dst_port;
 750       udp0->dst_port = new_port0 = ses0->in_port;
 751
 752       old_addr0 = ip0->dst_address;
 753       ip0->dst_address = new_addr0;
 754       vnet_buffer (b0)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 755
 756       sum0 = ip0->checksum;
 757       sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 758                              ip4_header_t, dst_address /* changed member */ );
 759       ip0->checksum = ip_csum_fold (sum0);
 760
 761       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 762         {
 763           if (tcp0->flags & TCP_FLAG_FIN
 764               && ses0->state == DET44_SESSION_TCP_ESTABLISHED)
 765             ses0->state = DET44_SESSION_TCP_CLOSE_WAIT;
 766           else if (tcp0->flags & TCP_FLAG_ACK
 767                    && ses0->state == DET44_SESSION_TCP_LAST_ACK)
 768             snat_det_ses_close (mp0, ses0);
 769
 770           sum0 = tcp0->checksum;
 771           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 772                                  ip4_header_t,
 773                                  dst_address /* changed member */ );
 774           sum0 = ip_csum_update (sum0, old_port0, new_port0,
 775                                  ip4_header_t /* cheat */ ,
 776                                  length /* changed member */ );
 777           tcp0->checksum = ip_csum_fold (sum0);
 778         }
 779       else if (udp0->checksum)
 780         {
 781           sum0 = udp0->checksum;
 782           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 783                                  ip4_header_t,
 784                                  dst_address /* changed member */ );
 785           sum0 = ip_csum_update (sum0, old_port0, new_port0,
 786                                  ip4_header_t /* cheat */ ,
 787                                  length /* changed member */ );
 788           udp0->checksum = ip_csum_fold (sum0);
 789         }
 790
 791     trace00:
 792
 793       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 794                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 795         {
 796           det44_out2in_trace_t *t =
 797             vlib_add_trace (vm, node, b0, sizeof (*t));
 798           t->sw_if_index = sw_if_index0;
 799           t->next_index = next0;
 800           t->session_index = ~0;
 801           if (ses0)
 802             t->session_index = ses0 - mp0->sessions;
 803         }
 804
 805       pkts_processed += next0 != DET44_OUT2IN_NEXT_DROP;
 806
 807       n_left_from--;
 808       next[0] = next0;
 809       next++;
 810     }
 811   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
 812                                frame->n_vectors);
 813
 814
 815   vlib_node_increment_counter (vm, dm->out2in_node_index,
 816                                DET44_OUT2IN_ERROR_OUT2IN_PACKETS,
 817                                pkts_processed);
 818   return frame->n_vectors;
 819 }
 820
 821 VLIB_REGISTER_NODE (det44_out2in_node) = {
 822   .name = "det44-out2in",
 823   .vector_size = sizeof (u32),
 824   .format_trace = format_det44_out2in_trace,
 825   .type = VLIB_NODE_TYPE_INTERNAL,
 826   .n_errors = ARRAY_LEN(det44_out2in_error_strings),
 827   .error_strings = det44_out2in_error_strings,
 828   .runtime_data_bytes = sizeof (det44_runtime_t),
 829   .n_next_nodes = DET44_OUT2IN_N_NEXT,
 830   /* edit / add dispositions here */
 831   .next_nodes = {
 832     [DET44_OUT2IN_NEXT_DROP] = "error-drop",
 833     [DET44_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
 834     [DET44_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 835   },
 836 };
 837
 838 /*
 839  * fd.io coding-style-patch-verification: ON
 840  *
 841  * Local Variables:
 842  * eval: (c-set-style "gnu")
 843  * End:
 844  */