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, *to_next;
 372   det44_out2in_next_t next_index;
 373   u32 pkts_processed = 0;
 374   det44_main_t *dm = &det44_main;
 375   u32 thread_index = vm->thread_index;
 376
 377   from = vlib_frame_vector_args (frame);
 378   n_left_from = frame->n_vectors;
 379   next_index = node->cached_next_index;
 380
 381   while (n_left_from > 0)
 382     {
 383       u32 n_left_to_next;
 384
 385       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 386
 387       while (n_left_from >= 4 && n_left_to_next >= 2)
 388         {
 389           u32 bi0, bi1;
 390           vlib_buffer_t *b0, *b1;
 391           u32 next0 = DET44_OUT2IN_NEXT_LOOKUP;
 392           u32 next1 = DET44_OUT2IN_NEXT_LOOKUP;
 393           u32 sw_if_index0, sw_if_index1;
 394           ip4_header_t *ip0, *ip1;
 395           ip_csum_t sum0, sum1;
 396           ip4_address_t new_addr0, old_addr0, new_addr1, old_addr1;
 397           u16 new_port0, old_port0, old_port1, new_port1;
 398           udp_header_t *udp0, *udp1;
 399           tcp_header_t *tcp0, *tcp1;
 400           u32 proto0, proto1;
 401           snat_det_out_key_t key0, key1;
 402           snat_det_map_t *mp0, *mp1;
 403           snat_det_session_t *ses0 = 0, *ses1 = 0;
 404           u32 rx_fib_index0, rx_fib_index1;
 405           icmp46_header_t *icmp0, *icmp1;
 406
 407           /* Prefetch next iteration. */
 408           {
 409             vlib_buffer_t *p2, *p3;
 410
 411             p2 = vlib_get_buffer (vm, from[2]);
 412             p3 = vlib_get_buffer (vm, from[3]);
 413
 414             vlib_prefetch_buffer_header (p2, LOAD);
 415             vlib_prefetch_buffer_header (p3, LOAD);
 416
 417             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
 418             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
 419           }
 420
 421           /* speculatively enqueue b0 and b1 to the current next frame */
 422           to_next[0] = bi0 = from[0];
 423           to_next[1] = bi1 = from[1];
 424           from += 2;
 425           to_next += 2;
 426           n_left_from -= 2;
 427           n_left_to_next -= 2;
 428
 429           b0 = vlib_get_buffer (vm, bi0);
 430           b1 = vlib_get_buffer (vm, bi1);
 431
 432           ip0 = vlib_buffer_get_current (b0);
 433           udp0 = ip4_next_header (ip0);
 434           tcp0 = (tcp_header_t *) udp0;
 435
 436           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 437
 438           if (PREDICT_FALSE (ip0->ttl == 1))
 439             {
 440               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 441               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 442                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 443                                            0);
 444               next0 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 445               goto trace0;
 446             }
 447
 448           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 449
 450           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 451             {
 452               rx_fib_index0 =
 453                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 454               icmp0 = (icmp46_header_t *) udp0;
 455
 456               next0 = det44_icmp_out2in (b0, ip0, icmp0, sw_if_index0,
 457                                          rx_fib_index0, node, next0,
 458                                          thread_index, &ses0, &mp0);
 459               goto trace0;
 460             }
 461
 462           key0.ext_host_addr = ip0->src_address;
 463           key0.ext_host_port = tcp0->src;
 464           key0.out_port = tcp0->dst;
 465
 466           mp0 = snat_det_map_by_out (&ip0->dst_address);
 467           if (PREDICT_FALSE (!mp0))
 468             {
 469               det44_log_info ("unknown dst address:  %U",
 470                               format_ip4_address, &ip0->dst_address);
 471               next0 = DET44_OUT2IN_NEXT_DROP;
 472               b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 473               goto trace0;
 474             }
 475
 476           snat_det_reverse (mp0, &ip0->dst_address,
 477                             clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 478
 479           ses0 = snat_det_get_ses_by_out (mp0, &new_addr0, key0.as_u64);
 480           if (PREDICT_FALSE (!ses0))
 481             {
 482               det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 483                               format_ip4_address, &ip0->src_address,
 484                               clib_net_to_host_u16 (tcp0->src),
 485                               format_ip4_address, &ip0->dst_address,
 486                               clib_net_to_host_u16 (tcp0->dst),
 487                               format_ip4_address, &new_addr0);
 488               next0 = DET44_OUT2IN_NEXT_DROP;
 489               b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 490               goto trace0;
 491             }
 492           old_port0 = udp0->dst_port;
 493           udp0->dst_port = new_port0 = ses0->in_port;
 494
 495           old_addr0 = ip0->dst_address;
 496           ip0->dst_address = new_addr0;
 497           vnet_buffer (b0)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 498
 499           sum0 = ip0->checksum;
 500           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 501                                  ip4_header_t,
 502                                  dst_address /* changed member */ );
 503           ip0->checksum = ip_csum_fold (sum0);
 504
 505           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 506             {
 507               if (tcp0->flags & TCP_FLAG_FIN
 508                   && ses0->state == DET44_SESSION_TCP_ESTABLISHED)
 509                 ses0->state = DET44_SESSION_TCP_CLOSE_WAIT;
 510               else if (tcp0->flags & TCP_FLAG_ACK
 511                        && ses0->state == DET44_SESSION_TCP_LAST_ACK)
 512                 snat_det_ses_close (mp0, ses0);
 513
 514               sum0 = tcp0->checksum;
 515               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 516                                      ip4_header_t,
 517                                      dst_address /* changed member */ );
 518               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 519                                      ip4_header_t /* cheat */ ,
 520                                      length /* changed member */ );
 521               tcp0->checksum = ip_csum_fold (sum0);
 522             }
 523           else if (udp0->checksum)
 524             {
 525               sum0 = udp0->checksum;
 526               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 527                                      ip4_header_t,
 528                                      dst_address /* changed member */ );
 529               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 530                                      ip4_header_t /* cheat */ ,
 531                                      length /* changed member */ );
 532               udp0->checksum = ip_csum_fold (sum0);
 533             }
 534
 535         trace0:
 536
 537           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 538                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 539             {
 540               det44_out2in_trace_t *t =
 541                 vlib_add_trace (vm, node, b0, sizeof (*t));
 542               t->sw_if_index = sw_if_index0;
 543               t->next_index = next0;
 544               t->session_index = ~0;
 545               if (ses0)
 546                 t->session_index = ses0 - mp0->sessions;
 547             }
 548
 549           pkts_processed += next0 != DET44_OUT2IN_NEXT_DROP;
 550
 551           b1 = vlib_get_buffer (vm, bi1);
 552
 553           ip1 = vlib_buffer_get_current (b1);
 554           udp1 = ip4_next_header (ip1);
 555           tcp1 = (tcp_header_t *) udp1;
 556
 557           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 558
 559           if (PREDICT_FALSE (ip1->ttl == 1))
 560             {
 561               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 562               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 563                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 564                                            0);
 565               next1 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 566               goto trace1;
 567             }
 568
 569           proto1 = ip_proto_to_nat_proto (ip1->protocol);
 570
 571           if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 572             {
 573               rx_fib_index1 =
 574                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index1);
 575               icmp1 = (icmp46_header_t *) udp1;
 576
 577               next1 = det44_icmp_out2in (b1, ip1, icmp1, sw_if_index1,
 578                                          rx_fib_index1, node, next1,
 579                                          thread_index, &ses1, &mp1);
 580               goto trace1;
 581             }
 582
 583           key1.ext_host_addr = ip1->src_address;
 584           key1.ext_host_port = tcp1->src;
 585           key1.out_port = tcp1->dst;
 586
 587           mp1 = snat_det_map_by_out (&ip1->dst_address);
 588           if (PREDICT_FALSE (!mp1))
 589             {
 590               det44_log_info ("unknown dst address:  %U",
 591                               format_ip4_address, &ip1->dst_address);
 592               next1 = DET44_OUT2IN_NEXT_DROP;
 593               b1->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 594               goto trace1;
 595             }
 596
 597           snat_det_reverse (mp1, &ip1->dst_address,
 598                             clib_net_to_host_u16 (tcp1->dst), &new_addr1);
 599
 600           ses1 = snat_det_get_ses_by_out (mp1, &new_addr1, key1.as_u64);
 601           if (PREDICT_FALSE (!ses1))
 602             {
 603               det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 604                               format_ip4_address, &ip1->src_address,
 605                               clib_net_to_host_u16 (tcp1->src),
 606                               format_ip4_address, &ip1->dst_address,
 607                               clib_net_to_host_u16 (tcp1->dst),
 608                               format_ip4_address, &new_addr1);
 609               next1 = DET44_OUT2IN_NEXT_DROP;
 610               b1->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 611               goto trace1;
 612             }
 613           old_port1 = udp1->dst_port;
 614           udp1->dst_port = new_port1 = ses1->in_port;
 615
 616           old_addr1 = ip1->dst_address;
 617           ip1->dst_address = new_addr1;
 618           vnet_buffer (b1)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 619
 620           sum1 = ip1->checksum;
 621           sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 622                                  ip4_header_t,
 623                                  dst_address /* changed member */ );
 624           ip1->checksum = ip_csum_fold (sum1);
 625
 626           if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
 627             {
 628               if (tcp1->flags & TCP_FLAG_FIN
 629                   && ses1->state == DET44_SESSION_TCP_ESTABLISHED)
 630                 ses1->state = DET44_SESSION_TCP_CLOSE_WAIT;
 631               else if (tcp1->flags & TCP_FLAG_ACK
 632                        && ses1->state == DET44_SESSION_TCP_LAST_ACK)
 633                 snat_det_ses_close (mp1, ses1);
 634
 635               sum1 = tcp1->checksum;
 636               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 637                                      ip4_header_t,
 638                                      dst_address /* changed member */ );
 639               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 640                                      ip4_header_t /* cheat */ ,
 641                                      length /* changed member */ );
 642               tcp1->checksum = ip_csum_fold (sum1);
 643             }
 644           else if (udp1->checksum)
 645             {
 646               sum1 = udp1->checksum;
 647               sum1 = ip_csum_update (sum1, old_addr1.as_u32, new_addr1.as_u32,
 648                                      ip4_header_t,
 649                                      dst_address /* changed member */ );
 650               sum1 = ip_csum_update (sum1, old_port1, new_port1,
 651                                      ip4_header_t /* cheat */ ,
 652                                      length /* changed member */ );
 653               udp1->checksum = ip_csum_fold (sum1);
 654             }
 655
 656         trace1:
 657
 658           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 659                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 660             {
 661               det44_out2in_trace_t *t =
 662                 vlib_add_trace (vm, node, b1, sizeof (*t));
 663               t->sw_if_index = sw_if_index1;
 664               t->next_index = next1;
 665               t->session_index = ~0;
 666               if (ses1)
 667                 t->session_index = ses1 - mp1->sessions;
 668             }
 669
 670           pkts_processed += next1 != DET44_OUT2IN_NEXT_DROP;
 671
 672           /* verify speculative enqueues, maybe switch current next frame */
 673           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 674                                            to_next, n_left_to_next,
 675                                            bi0, bi1, next0, next1);
 676         }
 677
 678       while (n_left_from > 0 && n_left_to_next > 0)
 679         {
 680           u32 bi0;
 681           vlib_buffer_t *b0;
 682           u32 next0 = DET44_OUT2IN_NEXT_LOOKUP;
 683           u32 sw_if_index0;
 684           ip4_header_t *ip0;
 685           ip_csum_t sum0;
 686           ip4_address_t new_addr0, old_addr0;
 687           u16 new_port0, old_port0;
 688           udp_header_t *udp0;
 689           tcp_header_t *tcp0;
 690           u32 proto0;
 691           snat_det_out_key_t key0;
 692           snat_det_map_t *mp0;
 693           snat_det_session_t *ses0 = 0;
 694           u32 rx_fib_index0;
 695           icmp46_header_t *icmp0;
 696
 697           /* speculatively enqueue b0 to the current next frame */
 698           bi0 = from[0];
 699           to_next[0] = bi0;
 700           from += 1;
 701           to_next += 1;
 702           n_left_from -= 1;
 703           n_left_to_next -= 1;
 704
 705           b0 = vlib_get_buffer (vm, bi0);
 706
 707           ip0 = vlib_buffer_get_current (b0);
 708           udp0 = ip4_next_header (ip0);
 709           tcp0 = (tcp_header_t *) udp0;
 710
 711           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 712
 713           if (PREDICT_FALSE (ip0->ttl == 1))
 714             {
 715               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 716               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 717                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 718                                            0);
 719               next0 = DET44_OUT2IN_NEXT_ICMP_ERROR;
 720               goto trace00;
 721             }
 722
 723           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 724
 725           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 726             {
 727               rx_fib_index0 =
 728                 ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 729               icmp0 = (icmp46_header_t *) udp0;
 730
 731               next0 = det44_icmp_out2in (b0, ip0, icmp0, sw_if_index0,
 732                                          rx_fib_index0, node, next0,
 733                                          thread_index, &ses0, &mp0);
 734               goto trace00;
 735             }
 736
 737           key0.ext_host_addr = ip0->src_address;
 738           key0.ext_host_port = tcp0->src;
 739           key0.out_port = tcp0->dst;
 740
 741           mp0 = snat_det_map_by_out (&ip0->dst_address);
 742           if (PREDICT_FALSE (!mp0))
 743             {
 744               det44_log_info ("unknown dst address:  %U",
 745                               format_ip4_address, &ip0->dst_address);
 746               next0 = DET44_OUT2IN_NEXT_DROP;
 747               b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 748               goto trace00;
 749             }
 750
 751           snat_det_reverse (mp0, &ip0->dst_address,
 752                             clib_net_to_host_u16 (tcp0->dst), &new_addr0);
 753
 754           ses0 = snat_det_get_ses_by_out (mp0, &new_addr0, key0.as_u64);
 755           if (PREDICT_FALSE (!ses0))
 756             {
 757               det44_log_info ("no match src %U:%d dst %U:%d for user %U",
 758                               format_ip4_address, &ip0->src_address,
 759                               clib_net_to_host_u16 (tcp0->src),
 760                               format_ip4_address, &ip0->dst_address,
 761                               clib_net_to_host_u16 (tcp0->dst),
 762                               format_ip4_address, &new_addr0);
 763               next0 = DET44_OUT2IN_NEXT_DROP;
 764               b0->error = node->errors[DET44_OUT2IN_ERROR_NO_TRANSLATION];
 765               goto trace00;
 766             }
 767           old_port0 = udp0->dst_port;
 768           udp0->dst_port = new_port0 = ses0->in_port;
 769
 770           old_addr0 = ip0->dst_address;
 771           ip0->dst_address = new_addr0;
 772           vnet_buffer (b0)->sw_if_index[VLIB_TX] = dm->inside_fib_index;
 773
 774           sum0 = ip0->checksum;
 775           sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 776                                  ip4_header_t,
 777                                  dst_address /* changed member */ );
 778           ip0->checksum = ip_csum_fold (sum0);
 779
 780           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 781             {
 782               if (tcp0->flags & TCP_FLAG_FIN
 783                   && ses0->state == DET44_SESSION_TCP_ESTABLISHED)
 784                 ses0->state = DET44_SESSION_TCP_CLOSE_WAIT;
 785               else if (tcp0->flags & TCP_FLAG_ACK
 786                        && ses0->state == DET44_SESSION_TCP_LAST_ACK)
 787                 snat_det_ses_close (mp0, ses0);
 788
 789               sum0 = tcp0->checksum;
 790               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 791                                      ip4_header_t,
 792                                      dst_address /* changed member */ );
 793               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 794                                      ip4_header_t /* cheat */ ,
 795                                      length /* changed member */ );
 796               tcp0->checksum = ip_csum_fold (sum0);
 797             }
 798           else if (udp0->checksum)
 799             {
 800               sum0 = udp0->checksum;
 801               sum0 = ip_csum_update (sum0, old_addr0.as_u32, new_addr0.as_u32,
 802                                      ip4_header_t,
 803                                      dst_address /* changed member */ );
 804               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 805                                      ip4_header_t /* cheat */ ,
 806                                      length /* changed member */ );
 807               udp0->checksum = ip_csum_fold (sum0);
 808             }
 809
 810         trace00:
 811
 812           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 813                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 814             {
 815               det44_out2in_trace_t *t =
 816                 vlib_add_trace (vm, node, b0, sizeof (*t));
 817               t->sw_if_index = sw_if_index0;
 818               t->next_index = next0;
 819               t->session_index = ~0;
 820               if (ses0)
 821                 t->session_index = ses0 - mp0->sessions;
 822             }
 823
 824           pkts_processed += next0 != DET44_OUT2IN_NEXT_DROP;
 825
 826           /* verify speculative enqueue, maybe switch current next frame */
 827           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 828                                            to_next, n_left_to_next,
 829                                            bi0, next0);
 830         }
 831
 832       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 833     }
 834
 835   vlib_node_increment_counter (vm, dm->out2in_node_index,
 836                                DET44_OUT2IN_ERROR_OUT2IN_PACKETS,
 837                                pkts_processed);
 838   return frame->n_vectors;
 839 }
 840
 841 /* *INDENT-OFF* */
 842 VLIB_REGISTER_NODE (det44_out2in_node) = {
 843   .name = "det44-out2in",
 844   .vector_size = sizeof (u32),
 845   .format_trace = format_det44_out2in_trace,
 846   .type = VLIB_NODE_TYPE_INTERNAL,
 847   .n_errors = ARRAY_LEN(det44_out2in_error_strings),
 848   .error_strings = det44_out2in_error_strings,
 849   .runtime_data_bytes = sizeof (det44_runtime_t),
 850   .n_next_nodes = DET44_OUT2IN_N_NEXT,
 851   /* edit / add dispositions here */
 852   .next_nodes = {
 853     [DET44_OUT2IN_NEXT_DROP] = "error-drop",
 854     [DET44_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
 855     [DET44_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
 856   },
 857 };
 858 /* *INDENT-ON* */
 859
 860 /*
 861  * fd.io coding-style-patch-verification: ON
 862  *
 863  * Local Variables:
 864  * eval: (c-set-style "gnu")
 865  * End:
 866  */