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       goto out;
 177     }
 178
 179   snat_det_reverse (mp0, &ip0->dst_address,
 180                     clib_net_to_host_u16 (key0.out_port), &new_addr0);
 181
 182   ses0 = snat_det_get_ses_by_out (mp0, &new_addr0, key0.as_u64);
 183   if (PREDICT_FALSE (!ses0))
 184     {
 185       /* Don't NAT packet aimed at the intfc address */
 186       if (PREDICT_FALSE (!det44_is_interface_addr (node, sw_if_index0,
 187                                                    ip0->dst_address.as_u32)))
 188         {
 189           *dont_translate = 1;
 190           goto out;
 191         }
 192       det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 193                       format_ip4_address, &key0.ext_host_addr,
 194                       clib_net_to_host_u16 (key0.ext_host_port),
 195                       format_ip4_address, &out_addr,
 196                       clib_net_to_host_u16 (key0.out_port),
 197                       format_ip4_address, &new_addr0);
 198       b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 199       next0 = DET44_OUT2IN_NEXT_DROP;
 200       goto out;
 201     }
 202
 203   if (PREDICT_FALSE
 204       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
 205        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 206                                        reass.icmp_type_or_tcp_flags)))
 207     {
 208       b0->error = node->errors[DET44_OUT2IN_ERROR_BAD_ICMP_TYPE];
 209       next0 = DET44_OUT2IN_NEXT_DROP;
 210       goto out;
 211     }
 212
 213   goto out;
 214
 215 out:
 216   *proto = protocol;
 217   if (ses0)
 218     {
 219       *addr = new_addr0;
 220       *fib_index = dm->inside_fib_index;
 221       *port = ses0->in_port;
 222     }
 223   if (d)
 224     *(snat_det_session_t **) d = ses0;
 225   if (e)
 226     *(snat_det_map_t **) e = mp0;
 227   return next0;
 228 }
 229 #endif
 230
 231 #ifndef CLIB_MARCH_VARIANT
 232 u32
 233 det44_icmp_out2in (vlib_buffer_t * b0,
 234                    ip4_header_t * ip0,
 235                    icmp46_header_t * icmp0,
 236                    u32 sw_if_index0,
 237                    u32 rx_fib_index0,
 238                    vlib_node_runtime_t * node,
 239                    u32 next0, u32 thread_index, void *d, void *e)
 240 {
 241   vlib_main_t *vm = vlib_get_main ();
 242   u32 new_addr0, old_addr0, next0_tmp, fib_index;
 243   u16 old_id0, new_id0, port, checksum0;
 244   icmp_echo_header_t *echo0, *inner_echo0;
 245   icmp46_header_t *inner_icmp0;
 246   ip4_header_t *inner_ip0;
 247   ip4_address_t addr;
 248   void *l4_header;
 249   u8 dont_translate;
 250   ip_csum_t sum0;
 251   nat_protocol_t proto;
 252
 253   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 254   next0_tmp = icmp_match_out2in_det (node, thread_index, b0, ip0,
 255                                      &addr, &port, &fib_index, &proto,
 256                                      d, e, &dont_translate);
 257   if (next0_tmp != ~0)
 258     next0 = next0_tmp;
 259   if (next0 == DET44_OUT2IN_NEXT_DROP || dont_translate)
 260     goto out;
 261
 262   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 263     {
 264       sum0 =
 265         ip_incremental_checksum_buffer (vm, b0,
 266                                         (u8 *) icmp0 -
 267                                         (u8 *) vlib_buffer_get_current (b0),
 268                                         ntohs (ip0->length) -
 269                                         ip4_header_bytes (ip0), 0);
 270       checksum0 = ~ip_csum_fold (sum0);
 271       if (checksum0 != 0 && checksum0 != 0xffff)
 272         {
 273           next0 = DET44_OUT2IN_NEXT_DROP;
 274           goto out;
 275         }
 276     }
 277
 278   old_addr0 = ip0->dst_address.as_u32;
 279   new_addr0 = ip0->dst_address.as_u32 = addr.as_u32;
 280   vnet_buffer (b0)->sw_if_index[VLIB_TX] = fib_index;
 281
 282   sum0 = ip0->checksum;
 283   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 284                          dst_address /* changed member */ );
 285   ip0->checksum = ip_csum_fold (sum0);
 286
 287
 288   if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 289     {
 290       if (icmp0->checksum == 0)
 291         icmp0->checksum = 0xffff;
 292
 293       if (!icmp_type_is_error_message (icmp0->type))
 294         {
 295           new_id0 = port;
 296           if (PREDICT_FALSE (new_id0 != echo0->identifier))
 297             {
 298               old_id0 = echo0->identifier;
 299               new_id0 = port;
 300               echo0->identifier = new_id0;
 301
 302               sum0 = icmp0->checksum;
 303               sum0 =
 304                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 305                                 identifier /* changed member */ );
 306               icmp0->checksum = ip_csum_fold (sum0);
 307             }
 308         }
 309       else
 310         {
 311           inner_ip0 = (ip4_header_t *) (echo0 + 1);
 312           l4_header = ip4_next_header (inner_ip0);
 313
 314           if (!ip4_header_checksum_is_valid (inner_ip0))
 315             {
 316               next0 = DET44_OUT2IN_NEXT_DROP;
 317               goto out;
 318             }
 319
 320           old_addr0 = inner_ip0->src_address.as_u32;
 321           inner_ip0->src_address = addr;
 322           new_addr0 = inner_ip0->src_address.as_u32;
 323
 324           sum0 = icmp0->checksum;
 325           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 326                                  src_address /* changed member */ );
 327           icmp0->checksum = ip_csum_fold (sum0);
 328
 329           switch (proto)
 330             {
 331             case NAT_PROTOCOL_ICMP:
 332               inner_icmp0 = (icmp46_header_t *) l4_header;
 333               inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 334
 335               old_id0 = inner_echo0->identifier;
 336               new_id0 = port;
 337               inner_echo0->identifier = new_id0;
 338
 339               sum0 = icmp0->checksum;
 340               sum0 =
 341                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 342                                 identifier);
 343               icmp0->checksum = ip_csum_fold (sum0);
 344               break;
 345             case NAT_PROTOCOL_UDP:
 346             case NAT_PROTOCOL_TCP:
 347               old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 348               new_id0 = port;
 349               ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 350
 351               sum0 = icmp0->checksum;
 352               sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 353                                      src_port);
 354               icmp0->checksum = ip_csum_fold (sum0);
 355               break;
 356             default:
 357               ASSERT (0);
 358             }
 359         }
 360     }
 361
 362 out:
 363   return next0;
 364 }
 365 #endif
 366
 367 VLIB_NODE_FN (det44_out2in_node) (vlib_main_t * vm,
 368                                   vlib_node_runtime_t * node,
 369                                   vlib_frame_t * frame)
 370 {
 371   u32 n_left_from, *from;
 372   u32 pkts_processed = 0;
 373   det44_main_t *dm = &det44_main;
 374   u32 thread_index = vm->thread_index;
 375
 376   from = vlib_frame_vector_args (frame);
 377   n_left_from = frame->n_vectors;
 378
 379   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
 380   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 381   vlib_get_buffers (vm, from, b, n_left_from);
 382
 383   while (n_left_from >= 2)
 384     {
 385       vlib_buffer_t *b0, *b1;
 386       u32 next0 = DET44_OUT2IN_NEXT_LOOKUP;
 387       u32 next1 = DET44_OUT2IN_NEXT_LOOKUP;
 388       u32 sw_if_index0, sw_if_index1;
 389       ip4_header_t *ip0, *ip1;
 390       ip_csum_t sum0, sum1;
 391       ip4_address_t new_addr0, old_addr0, new_addr1, old_addr1;
 392       u16 new_port0, old_port0, old_port1, new_port1;
 393       udp_header_t *udp0, *udp1;
 394       tcp_header_t *tcp0, *tcp1;
 395       u32 proto0, proto1;
 396       snat_det_out_key_t key0, key1;
 397       snat_det_map_t *mp0, *mp1;
 398       snat_det_session_t *ses0 = 0, *ses1 = 0;
 399       u32 rx_fib_index0, rx_fib_index1;
 400       icmp46_header_t *icmp0, *icmp1;
 401
 402       b0 = *b;
 403       b++;
 404       b1 = *b;
 405       b++;
 406
 407       /* Prefetch next iteration. */
 408       if (PREDICT_TRUE (n_left_from >= 4))
 409         {
 410           vlib_buffer_t *p2, *p3;
 411
 412           p2 = *b;
 413           p3 = *(b + 1);
 414
 415           vlib_prefetch_buffer_header (p2, LOAD);
 416           vlib_prefetch_buffer_header (p3, LOAD);
 417
 418           CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
 419           CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
 420         }
 421
 422
 423       ip0 = vlib_buffer_get_current (b0);
 424       udp0 = ip4_next_header (ip0);
 425       tcp0 = (tcp_header_t *) udp0;
 426
 427       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 428
 429       if (PREDICT_FALSE (ip0->ttl == 1))
 430         {
 431           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 432           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 433                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 434                                        0);
 435           next0 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 436           goto trace0;
 437         }
 438
 439       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 440
 441       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 442         {
 443           rx_fib_index0 =
 444             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 445           icmp0 = (icmp46_header_t *) udp0;
 446
 447           next0 = det44_icmp_out2in (b0, ip0, icmp0, sw_if_index0,
 448                                      rx_fib_index0, node, next0,
 449                                      thread_index, &ses0, &mp0);
 450           goto trace0;
 451         }
 452
 453       key0.ext_host_addr = ip0->src_address;
 454       key0.ext_host_port = tcp0->src;
 455       key0.out_port = tcp0->dst;
 456
 457       mp0 = snat_det_map_by_out (&ip0->dst_address);
 458       if (PREDICT_FALSE (!mp0))
 459         {
 460           det44_log_info ("unknown dst address:  %U",
 461                           format_ip4_address, &ip0->dst_address);
 462           next0 = DET44_OUT2IN_NEXT_DROP;
 463           b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 464           goto trace0;
 465         }
 466
 467       snat_det_reverse (mp0, &ip0->dst_address,
 468                         clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 469
 470       ses0 = snat_det_get_ses_by_out (mp0, &new_addr0, key0.as_u64);
 471       if (PREDICT_FALSE (!ses0))
 472         {
 473           det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 474                           format_ip4_address, &ip0->src_address,
 475                           clib_net_to_host_u16 (tcp0->src),
 476                           format_ip4_address, &ip0->dst_address,
 477                           clib_net_to_host_u16 (tcp0->dst),
 478                           format_ip4_address, &new_addr0);
 479           next0 = DET44_OUT2IN_NEXT_DROP;
 480           b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 481           goto trace0;
 482         }
 483       old_port0 = udp0->dst_port;
 484       udp0->dst_port = new_port0 = ses0->in_port;
 485
 486       old_addr0 = ip0->dst_address;
 487       ip0->dst_address = new_addr0;
 488       vnet_buffer (b0)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 489
 490       sum0 = ip0->checksum;
 491       sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 492                              ip4_header_t, dst_address /* changed member */ );
 493       ip0->checksum = ip_csum_fold (sum0);
 494
 495       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 496         {
 497           if (tcp0->flags & TCP_FLAG_FIN
 498               && ses0->state == DET44_SESSION_TCP_ESTABLISHED)
 499             ses0->state = DET44_SESSION_TCP_CLOSE_WAIT;
 500           else if (tcp0->flags & TCP_FLAG_ACK
 501                    && ses0->state == DET44_SESSION_TCP_LAST_ACK)
 502             snat_det_ses_close (mp0, ses0);
 503
 504           sum0 = tcp0->checksum;
 505           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 506                                  ip4_header_t,
 507                                  dst_address /* changed member */ );
 508           sum0 = ip_csum_update (sum0, old_port0, new_port0,
 509                                  ip4_header_t /* cheat */ ,
 510                                  length /* changed member */ );
 511           tcp0->checksum = ip_csum_fold (sum0);
 512         }
 513       else if (udp0->checksum)
 514         {
 515           sum0 = udp0->checksum;
 516           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 517                                  ip4_header_t,
 518                                  dst_address /* changed member */ );
 519           sum0 = ip_csum_update (sum0, old_port0, new_port0,
 520                                  ip4_header_t /* cheat */ ,
 521                                  length /* changed member */ );
 522           udp0->checksum = ip_csum_fold (sum0);
 523         }
 524
 525     trace0:
 526
 527       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 528                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 529         {
 530           det44_out2in_trace_t *t =
 531             vlib_add_trace (vm, node, b0, sizeof (*t));
 532           t->sw_if_index = sw_if_index0;
 533           t->next_index = next0;
 534           t->session_index = ~0;
 535           if (ses0)
 536             t->session_index = ses0 - mp0->sessions;
 537         }
 538
 539       pkts_processed += next0 != DET44_OUT2IN_NEXT_DROP;
 540
 541       ip1 = vlib_buffer_get_current (b1);
 542       udp1 = ip4_next_header (ip1);
 543       tcp1 = (tcp_header_t *) udp1;
 544
 545       sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 546
 547       if (PREDICT_FALSE (ip1->ttl == 1))
 548         {
 549           vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 550           icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 551                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 552                                        0);
 553           next1 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 554           goto trace1;
 555         }
 556
 557       proto1 = ip_proto_to_nat_proto (ip1->protocol);
 558
 559       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 560         {
 561           rx_fib_index1 =
 562             ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 563           icmp1 = (icmp46_header_t *) udp1;
 564
 565           next1 = det44_icmp_out2in (b1, ip1, icmp1, sw_if_index1,
 566                                      rx_fib_index1, node, next1,
 567                                      thread_index, &ses1, &mp1);
 568           goto trace1;
 569         }
 570
 571       key1.ext_host_addr = ip1->src_address;
 572       key1.ext_host_port = tcp1->src;
 573       key1.out_port = tcp1->dst;
 574
 575       mp1 = snat_det_map_by_out (&ip1->dst_address);
 576       if (PREDICT_FALSE (!mp1))
 577         {
 578           det44_log_info ("unknown dst address:  %U",
 579                           format_ip4_address, &ip1->dst_address);
 580           next1 = DET44_OUT2IN_NEXT_DROP;
 581           b1->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 582           goto trace1;
 583         }
 584
 585       snat_det_reverse (mp1, &ip1->dst_address,
 586                         clib_net_to_host_u16 (tcp1->dst), &new_addr1);
 587
 588       ses1 = snat_det_get_ses_by_out (mp1, &new_addr1, key1.as_u64);
 589       if (PREDICT_FALSE (!ses1))
 590         {
 591           det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 592                           format_ip4_address, &ip1->src_address,
 593                           clib_net_to_host_u16 (tcp1->src),
 594                           format_ip4_address, &ip1->dst_address,
 595                           clib_net_to_host_u16 (tcp1->dst),
 596                           format_ip4_address, &new_addr1);
 597           next1 = DET44_OUT2IN_NEXT_DROP;
 598           b1->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 599           goto trace1;
 600         }
 601       old_port1 = udp1->dst_port;
 602       udp1->dst_port = new_port1 = ses1->in_port;
 603
 604       old_addr1 = ip1->dst_address;
 605       ip1->dst_address = new_addr1;
 606       vnet_buffer (b1)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 607
 608       sum1 = ip1->checksum;
 609       sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 610                              ip4_header_t, dst_address /* changed member */ );
 611       ip1->checksum = ip_csum_fold (sum1);
 612
 613       if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
 614         {
 615           if (tcp1->flags & TCP_FLAG_FIN
 616               && ses1->state == DET44_SESSION_TCP_ESTABLISHED)
 617             ses1->state = DET44_SESSION_TCP_CLOSE_WAIT;
 618           else if (tcp1->flags & TCP_FLAG_ACK
 619                    && ses1->state == DET44_SESSION_TCP_LAST_ACK)
 620             snat_det_ses_close (mp1, ses1);
 621
 622           sum1 = tcp1->checksum;
 623           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 624                                  ip4_header_t,
 625                                  dst_address /* changed member */ );
 626           sum1 = ip_csum_update (sum1, old_port1, new_port1,
 627                                  ip4_header_t /* cheat */ ,
 628                                  length /* changed member */ );
 629           tcp1->checksum = ip_csum_fold (sum1);
 630         }
 631       else if (udp1->checksum)
 632         {
 633           sum1 = udp1->checksum;
 634           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 635                                  ip4_header_t,
 636                                  dst_address /* changed member */ );
 637           sum1 = ip_csum_update (sum1, old_port1, new_port1,
 638                                  ip4_header_t /* cheat */ ,
 639                                  length /* changed member */ );
 640           udp1->checksum = ip_csum_fold (sum1);
 641         }
 642
 643     trace1:
 644
 645       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 646                          && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 647         {
 648           det44_out2in_trace_t *t =
 649             vlib_add_trace (vm, node, b1, sizeof (*t));
 650           t->sw_if_index = sw_if_index1;
 651           t->next_index = next1;
 652           t->session_index = ~0;
 653           if (ses1)
 654             t->session_index = ses1 - mp1->sessions;
 655         }
 656
 657       pkts_processed += next1 != DET44_OUT2IN_NEXT_DROP;
 658
 659       n_left_from -= 2;
 660       next[0] = next0;
 661       next[1] = next1;
 662       next += 2;
 663     }
 664
 665   while (n_left_from > 0)
 666     {
 667       vlib_buffer_t *b0;
 668       u32 next0 = DET44_OUT2IN_NEXT_LOOKUP;
 669       u32 sw_if_index0;
 670       ip4_header_t *ip0;
 671       ip_csum_t sum0;
 672       ip4_address_t new_addr0, old_addr0;
 673       u16 new_port0, old_port0;
 674       udp_header_t *udp0;
 675       tcp_header_t *tcp0;
 676       u32 proto0;
 677       snat_det_out_key_t key0;
 678       snat_det_map_t *mp0;
 679       snat_det_session_t *ses0 = 0;
 680       u32 rx_fib_index0;
 681       icmp46_header_t *icmp0;
 682
 683       b0 = *b;
 684       b++;
 685
 686       ip0 = vlib_buffer_get_current (b0);
 687       udp0 = ip4_next_header (ip0);
 688       tcp0 = (tcp_header_t *) udp0;
 689
 690       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 691
 692       if (PREDICT_FALSE (ip0->ttl == 1))
 693         {
 694           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 695           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 696                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 697                                        0);
 698           next0 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 699           goto trace00;
 700         }
 701
 702       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 703
 704       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 705         {
 706           rx_fib_index0 =
 707             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 708           icmp0 = (icmp46_header_t *) udp0;
 709
 710           next0 = det44_icmp_out2in (b0, ip0, icmp0, sw_if_index0,
 711                                      rx_fib_index0, node, next0,
 712                                      thread_index, &ses0, &mp0);
 713           goto trace00;
 714         }
 715
 716       key0.ext_host_addr = ip0->src_address;
 717       key0.ext_host_port = tcp0->src;
 718       key0.out_port = tcp0->dst;
 719
 720       mp0 = snat_det_map_by_out (&ip0->dst_address);
 721       if (PREDICT_FALSE (!mp0))
 722         {
 723           det44_log_info ("unknown dst address:  %U",
 724                           format_ip4_address, &ip0->dst_address);
 725           next0 = DET44_OUT2IN_NEXT_DROP;
 726           b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 727           goto trace00;
 728         }
 729
 730       snat_det_reverse (mp0, &ip0->dst_address,
 731                         clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 732
 733       ses0 = snat_det_get_ses_by_out (mp0, &new_addr0, key0.as_u64);
 734       if (PREDICT_FALSE (!ses0))
 735         {
 736           det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 737                           format_ip4_address, &ip0->src_address,
 738                           clib_net_to_host_u16 (tcp0->src),
 739                           format_ip4_address, &ip0->dst_address,
 740                           clib_net_to_host_u16 (tcp0->dst),
 741                           format_ip4_address, &new_addr0);
 742           next0 = DET44_OUT2IN_NEXT_DROP;
 743           b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 744           goto trace00;
 745         }
 746       old_port0 = udp0->dst_port;
 747       udp0->dst_port = new_port0 = ses0->in_port;
 748
 749       old_addr0 = ip0->dst_address;
 750       ip0->dst_address = new_addr0;
 751       vnet_buffer (b0)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 752
 753       sum0 = ip0->checksum;
 754       sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 755                              ip4_header_t, dst_address /* changed member */ );
 756       ip0->checksum = ip_csum_fold (sum0);
 757
 758       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 759         {
 760           if (tcp0->flags & TCP_FLAG_FIN
 761               && ses0->state == DET44_SESSION_TCP_ESTABLISHED)
 762             ses0->state = DET44_SESSION_TCP_CLOSE_WAIT;
 763           else if (tcp0->flags & TCP_FLAG_ACK
 764                    && ses0->state == DET44_SESSION_TCP_LAST_ACK)
 765             snat_det_ses_close (mp0, ses0);
 766
 767           sum0 = tcp0->checksum;
 768           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 769                                  ip4_header_t,
 770                                  dst_address /* changed member */ );
 771           sum0 = ip_csum_update (sum0, old_port0, new_port0,
 772                                  ip4_header_t /* cheat */ ,
 773                                  length /* changed member */ );
 774           tcp0->checksum = ip_csum_fold (sum0);
 775         }
 776       else if (udp0->checksum)
 777         {
 778           sum0 = udp0->checksum;
 779           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 780                                  ip4_header_t,
 781                                  dst_address /* changed member */ );
 782           sum0 = ip_csum_update (sum0, old_port0, new_port0,
 783                                  ip4_header_t /* cheat */ ,
 784                                  length /* changed member */ );
 785           udp0->checksum = ip_csum_fold (sum0);
 786         }
 787
 788     trace00:
 789
 790       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 791                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 792         {
 793           det44_out2in_trace_t *t =
 794             vlib_add_trace (vm, node, b0, sizeof (*t));
 795           t->sw_if_index = sw_if_index0;
 796           t->next_index = next0;
 797           t->session_index = ~0;
 798           if (ses0)
 799             t->session_index = ses0 - mp0->sessions;
 800         }
 801
 802       pkts_processed += next0 != DET44_OUT2IN_NEXT_DROP;
 803
 804       n_left_from--;
 805       next[0] = next0;
 806       next++;
 807     }
 808   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
 809                                frame->n_vectors);
 810
 811
 812   vlib_node_increment_counter (vm, dm->out2in_node_index,
 813                                DET44_OUT2IN_ERROR_OUT2IN_PACKETS,
 814                                pkts_processed);
 815   return frame->n_vectors;
 816 }
 817
 818 /* *INDENT-OFF* */
 819 VLIB_REGISTER_NODE (det44_out2in_node) = {
 820   .name = "det44-out2in",
 821   .vector_size = sizeof (u32),
 822   .format_trace = format_det44_out2in_trace,
 823   .type = VLIB_NODE_TYPE_INTERNAL,
 824   .n_errors = ARRAY_LEN(det44_out2in_error_strings),
 825   .error_strings = det44_out2in_error_strings,
 826   .runtime_data_bytes = sizeof (det44_runtime_t),
 827   .n_next_nodes = DET44_OUT2IN_N_NEXT,
 828   /* edit / add dispositions here */
 829   .next_nodes = {
 830     [DET44_OUT2IN_NEXT_DROP] = "error-drop",
 831     [DET44_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
 832     [DET44_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 833   },
 834 };
 835 /* *INDENT-ON* */
 836
 837 /*
 838  * fd.io coding-style-patch-verification: ON
 839  *
 840  * Local Variables:
 841  * eval: (c-set-style "gnu")
 842  * End:
 843  */