src/plugins/nat/out2in.c

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 /**
  16  * @file
  17  * @brief NAT44 endpoint-dependent outside to inside network translation
  18  */
  19
  20 #include <vlib/vlib.h>
  21 #include <vnet/vnet.h>
  22 #include <vnet/pg/pg.h>
  23
  24 #include <vnet/ip/ip.h>
  25 #include <vnet/udp/udp.h>
  26 #include <vnet/ethernet/ethernet.h>
  27 #include <vnet/fib/ip4_fib.h>
  28 #include <nat/nat.h>
  29 #include <nat/nat_ipfix_logging.h>
  30 #include <nat/nat_reass.h>
  31 #include <nat/nat_inlines.h>
  32 #include <nat/nat_syslog.h>
  33
  34 #include <vppinfra/hash.h>
  35 #include <vppinfra/error.h>
  36 #include <vppinfra/elog.h>
  37
  38 typedef struct
  39 {
  40   u32 sw_if_index;
  41   u32 next_index;
  42   u32 session_index;
  43 } snat_out2in_trace_t;
  44
  45 /* packet trace format function */
  46 static u8 *
  47 format_snat_out2in_trace (u8 * s, va_list * args)
  48 {
  49   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  50   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  51   snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
  52
  53   s =
  54     format (s,
  55             "NAT44_OUT2IN: sw_if_index %d, next index %d, session index %d",
  56             t->sw_if_index, t->next_index, t->session_index);
  57   return s;
  58 }
  59
  60 static u8 *
  61 format_snat_out2in_fast_trace (u8 * s, va_list * args)
  62 {
  63   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  64   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  65   snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
  66
  67   s = format (s, "NAT44_OUT2IN_FAST: sw_if_index %d, next index %d",
  68               t->sw_if_index, t->next_index);
  69   return s;
  70 }
  71
  72 vlib_node_registration_t snat_out2in_node;
  73 vlib_node_registration_t snat_out2in_fast_node;
  74 vlib_node_registration_t nat44_out2in_reass_node;
  75
  76 #define foreach_snat_out2in_error                       \
  77 _(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
  78 _(OUT2IN_PACKETS, "good out2in packets processed")      \
  79 _(OUT_OF_PORTS, "out of ports")                         \
  80 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  81 _(NO_TRANSLATION, "no translation")                     \
  82 _(MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")   \
  83 _(DROP_FRAGMENT, "drop fragment")                       \
  84 _(MAX_REASS, "maximum reassemblies exceeded")           \
  85 _(MAX_FRAG, "maximum fragments per reassembly exceeded")\
  86 _(TCP_PACKETS, "TCP packets")                           \
  87 _(UDP_PACKETS, "UDP packets")                           \
  88 _(ICMP_PACKETS, "ICMP packets")                         \
  89 _(OTHER_PACKETS, "other protocol packets")              \
  90 _(FRAGMENTS, "fragments")                               \
  91 _(CACHED_FRAGMENTS, "cached fragments")                 \
  92 _(PROCESSED_FRAGMENTS, "processed fragments")
  93
  94 typedef enum
  95 {
  96 #define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
  97   foreach_snat_out2in_error
  98 #undef _
  99     SNAT_OUT2IN_N_ERROR,
 100 } snat_out2in_error_t;
 101
 102 static char *snat_out2in_error_strings[] = {
 103 #define _(sym,string) string,
 104   foreach_snat_out2in_error
 105 #undef _
 106 };
 107
 108 typedef enum
 109 {
 110   SNAT_OUT2IN_NEXT_DROP,
 111   SNAT_OUT2IN_NEXT_LOOKUP,
 112   SNAT_OUT2IN_NEXT_ICMP_ERROR,
 113   SNAT_OUT2IN_NEXT_REASS,
 114   SNAT_OUT2IN_N_NEXT,
 115 } snat_out2in_next_t;
 116
 117 int
 118 nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 119 {
 120   snat_main_t *sm = &snat_main;
 121   nat44_is_idle_session_ctx_t *ctx = arg;
 122   snat_session_t *s;
 123   u64 sess_timeout_time;
 124   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
 125                                                        ctx->thread_index);
 126   clib_bihash_kv_8_8_t s_kv;
 127
 128   s = pool_elt_at_index (tsm->sessions, kv->value);
 129   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
 130   if (ctx->now >= sess_timeout_time)
 131     {
 132       s_kv.key = s->in2out.as_u64;
 133       if (clib_bihash_add_del_8_8 (&tsm->in2out, &s_kv, 0))
 134         nat_log_warn ("out2in key del failed");
 135
 136       snat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
 137                                            s->in2out.addr.as_u32,
 138                                            s->out2in.addr.as_u32,
 139                                            s->in2out.protocol,
 140                                            s->in2out.port,
 141                                            s->out2in.port,
 142                                            s->in2out.fib_index);
 143
 144       nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
 145                                &s->in2out.addr, s->in2out.port,
 146                                &s->out2in.addr, s->out2in.port,
 147                                s->in2out.protocol);
 148
 149       if (!snat_is_session_static (s))
 150         snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
 151                                             &s->out2in);
 152
 153       nat44_delete_session (sm, s, ctx->thread_index);
 154       return 1;
 155     }
 156
 157   return 0;
 158 }
 159
 160 /**
 161  * @brief Create session for static mapping.
 162  *
 163  * Create NAT session initiated by host from external network with static
 164  * mapping.
 165  *
 166  * @param sm     NAT main.
 167  * @param b0     Vlib buffer.
 168  * @param in2out In2out NAT44 session key.
 169  * @param out2in Out2in NAT44 session key.
 170  * @param node   Vlib node.
 171  *
 172  * @returns SNAT session if successfully created otherwise 0.
 173  */
 174 static inline snat_session_t *
 175 create_session_for_static_mapping (snat_main_t * sm,
 176                                    vlib_buffer_t * b0,
 177                                    snat_session_key_t in2out,
 178                                    snat_session_key_t out2in,
 179                                    vlib_node_runtime_t * node,
 180                                    u32 thread_index, f64 now)
 181 {
 182   snat_user_t *u;
 183   snat_session_t *s;
 184   clib_bihash_kv_8_8_t kv0;
 185   ip4_header_t *ip0;
 186   udp_header_t *udp0;
 187   nat44_is_idle_session_ctx_t ctx0;
 188
 189   if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 190     {
 191       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
 192       nat_log_notice ("maximum sessions exceeded");
 193       return 0;
 194     }
 195
 196   ip0 = vlib_buffer_get_current (b0);
 197   udp0 = ip4_next_header (ip0);
 198
 199   u =
 200     nat_user_get_or_create (sm, &in2out.addr, in2out.fib_index, thread_index);
 201   if (!u)
 202     {
 203       nat_log_warn ("create NAT user failed");
 204       return 0;
 205     }
 206
 207   s = nat_session_alloc_or_recycle (sm, u, thread_index);
 208   if (!s)
 209     {
 210       nat44_delete_user_with_no_session (sm, u, thread_index);
 211       nat_log_warn ("create NAT session failed");
 212       return 0;
 213     }
 214
 215   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 216   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
 217   s->ext_host_port = udp0->src_port;
 218   user_session_increment (sm, u, 1 /* static */ );
 219   s->in2out = in2out;
 220   s->out2in = out2in;
 221   s->in2out.protocol = out2in.protocol;
 222
 223   /* Add to translation hashes */
 224   ctx0.now = now;
 225   ctx0.thread_index = thread_index;
 226   kv0.key = s->in2out.as_u64;
 227   kv0.value = s - sm->per_thread_data[thread_index].sessions;
 228   if (clib_bihash_add_or_overwrite_stale_8_8
 229       (&sm->per_thread_data[thread_index].in2out, &kv0,
 230        nat44_i2o_is_idle_session_cb, &ctx0))
 231     nat_log_notice ("in2out key add failed");
 232
 233   kv0.key = s->out2in.as_u64;
 234
 235   if (clib_bihash_add_or_overwrite_stale_8_8
 236       (&sm->per_thread_data[thread_index].out2in, &kv0,
 237        nat44_o2i_is_idle_session_cb, &ctx0))
 238     nat_log_notice ("out2in key add failed");
 239
 240   /* log NAT event */
 241   snat_ipfix_logging_nat44_ses_create (thread_index,
 242                                        s->in2out.addr.as_u32,
 243                                        s->out2in.addr.as_u32,
 244                                        s->in2out.protocol,
 245                                        s->in2out.port,
 246                                        s->out2in.port, s->in2out.fib_index);
 247
 248   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
 249                            &s->in2out.addr, s->in2out.port, &s->out2in.addr,
 250                            s->out2in.port, s->in2out.protocol);
 251
 252   return s;
 253 }
 254
 255 static_always_inline
 256   snat_out2in_error_t icmp_get_key (ip4_header_t * ip0,
 257                                     snat_session_key_t * p_key0)
 258 {
 259   icmp46_header_t *icmp0;
 260   snat_session_key_t key0;
 261   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 262   ip4_header_t *inner_ip0;
 263   void *l4_header = 0;
 264   icmp46_header_t *inner_icmp0;
 265
 266   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 267   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 268
 269   if (!icmp_is_error_message (icmp0))
 270     {
 271       key0.protocol = SNAT_PROTOCOL_ICMP;
 272       key0.addr = ip0->dst_address;
 273       key0.port = echo0->identifier;
 274     }
 275   else
 276     {
 277       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 278       l4_header = ip4_next_header (inner_ip0);
 279       key0.protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 280       key0.addr = inner_ip0->src_address;
 281       switch (key0.protocol)
 282         {
 283         case SNAT_PROTOCOL_ICMP:
 284           inner_icmp0 = (icmp46_header_t *) l4_header;
 285           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 286           key0.port = inner_echo0->identifier;
 287           break;
 288         case SNAT_PROTOCOL_UDP:
 289         case SNAT_PROTOCOL_TCP:
 290           key0.port = ((tcp_udp_header_t *) l4_header)->src_port;
 291           break;
 292         default:
 293           return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
 294         }
 295     }
 296   *p_key0 = key0;
 297   return -1;                    /* success */
 298 }
 299
 300 /**
 301  * Get address and port values to be used for ICMP packet translation
 302  * and create session if needed
 303  *
 304  * @param[in,out] sm             NAT main
 305  * @param[in,out] node           NAT node runtime
 306  * @param[in] thread_index       thread index
 307  * @param[in,out] b0             buffer containing packet to be translated
 308  * @param[out] p_proto           protocol used for matching
 309  * @param[out] p_value           address and port after NAT translation
 310  * @param[out] p_dont_translate  if packet should not be translated
 311  * @param d                      optional parameter
 312  * @param e                      optional parameter
 313  */
 314 u32
 315 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 316                         u32 thread_index, vlib_buffer_t * b0,
 317                         ip4_header_t * ip0, u8 * p_proto,
 318                         snat_session_key_t * p_value,
 319                         u8 * p_dont_translate, void *d, void *e)
 320 {
 321   icmp46_header_t *icmp0;
 322   u32 sw_if_index0;
 323   u32 rx_fib_index0;
 324   snat_session_key_t key0;
 325   snat_session_key_t sm0;
 326   snat_session_t *s0 = 0;
 327   u8 dont_translate = 0;
 328   clib_bihash_kv_8_8_t kv0, value0;
 329   u8 is_addr_only;
 330   u32 next0 = ~0;
 331   int err;
 332   u8 identity_nat;
 333
 334   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 335   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 336   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 337
 338   key0.protocol = 0;
 339
 340   err = icmp_get_key (ip0, &key0);
 341   if (err != -1)
 342     {
 343       b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 344       next0 = SNAT_OUT2IN_NEXT_DROP;
 345       goto out;
 346     }
 347   key0.fib_index = rx_fib_index0;
 348
 349   kv0.key = key0.as_u64;
 350
 351   if (clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].out2in, &kv0,
 352                               &value0))
 353     {
 354       /* Try to match static mapping by external address and port,
 355          destination address and port in packet */
 356       if (snat_static_mapping_match
 357           (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0, &identity_nat))
 358         {
 359           if (!sm->forwarding_enabled)
 360             {
 361               /* Don't NAT packet aimed at the intfc address */
 362               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 363                                                     ip0->dst_address.as_u32)))
 364                 {
 365                   dont_translate = 1;
 366                   goto out;
 367                 }
 368               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 369               next0 = SNAT_OUT2IN_NEXT_DROP;
 370               goto out;
 371             }
 372           else
 373             {
 374               dont_translate = 1;
 375               goto out;
 376             }
 377         }
 378
 379       if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
 380                          (icmp0->type != ICMP4_echo_request
 381                           || !is_addr_only)))
 382         {
 383           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 384           next0 = SNAT_OUT2IN_NEXT_DROP;
 385           goto out;
 386         }
 387
 388       if (PREDICT_FALSE (identity_nat))
 389         {
 390           dont_translate = 1;
 391           goto out;
 392         }
 393       /* Create session initiated by host from external network */
 394       s0 = create_session_for_static_mapping (sm, b0, sm0, key0,
 395                                               node, thread_index,
 396                                               vlib_time_now (sm->vlib_main));
 397
 398       if (!s0)
 399         {
 400           next0 = SNAT_OUT2IN_NEXT_DROP;
 401           goto out;
 402         }
 403     }
 404   else
 405     {
 406       if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
 407                          icmp0->type != ICMP4_echo_request &&
 408                          !icmp_is_error_message (icmp0)))
 409         {
 410           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 411           next0 = SNAT_OUT2IN_NEXT_DROP;
 412           goto out;
 413         }
 414
 415       s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 416                               value0.value);
 417     }
 418
 419 out:
 420   *p_proto = key0.protocol;
 421   if (s0)
 422     *p_value = s0->in2out;
 423   *p_dont_translate = dont_translate;
 424   if (d)
 425     *(snat_session_t **) d = s0;
 426   return next0;
 427 }
 428
 429 /**
 430  * Get address and port values to be used for ICMP packet translation
 431  *
 432  * @param[in] sm                 NAT main
 433  * @param[in,out] node           NAT node runtime
 434  * @param[in] thread_index       thread index
 435  * @param[in,out] b0             buffer containing packet to be translated
 436  * @param[out] p_proto           protocol used for matching
 437  * @param[out] p_value           address and port after NAT translation
 438  * @param[out] p_dont_translate  if packet should not be translated
 439  * @param d                      optional parameter
 440  * @param e                      optional parameter
 441  */
 442 u32
 443 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
 444                         u32 thread_index, vlib_buffer_t * b0,
 445                         ip4_header_t * ip0, u8 * p_proto,
 446                         snat_session_key_t * p_value,
 447                         u8 * p_dont_translate, void *d, void *e)
 448 {
 449   icmp46_header_t *icmp0;
 450   u32 sw_if_index0;
 451   u32 rx_fib_index0;
 452   snat_session_key_t key0;
 453   snat_session_key_t sm0;
 454   u8 dont_translate = 0;
 455   u8 is_addr_only;
 456   u32 next0 = ~0;
 457   int err;
 458
 459   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 460   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 461   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 462
 463   err = icmp_get_key (ip0, &key0);
 464   if (err != -1)
 465     {
 466       b0->error = node->errors[err];
 467       next0 = SNAT_OUT2IN_NEXT_DROP;
 468       goto out2;
 469     }
 470   key0.fib_index = rx_fib_index0;
 471
 472   if (snat_static_mapping_match
 473       (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0, 0))
 474     {
 475       /* Don't NAT packet aimed at the intfc address */
 476       if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
 477         {
 478           dont_translate = 1;
 479           goto out;
 480         }
 481       b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 482       next0 = SNAT_OUT2IN_NEXT_DROP;
 483       goto out;
 484     }
 485
 486   if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
 487                      (icmp0->type != ICMP4_echo_request || !is_addr_only) &&
 488                      !icmp_is_error_message (icmp0)))
 489     {
 490       b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 491       next0 = SNAT_OUT2IN_NEXT_DROP;
 492       goto out;
 493     }
 494
 495 out:
 496   *p_value = sm0;
 497 out2:
 498   *p_proto = key0.protocol;
 499   *p_dont_translate = dont_translate;
 500   return next0;
 501 }
 502
 503 u32
 504 icmp_out2in (snat_main_t * sm,
 505              vlib_buffer_t * b0,
 506              ip4_header_t * ip0,
 507              icmp46_header_t * icmp0,
 508              u32 sw_if_index0,
 509              u32 rx_fib_index0,
 510              vlib_node_runtime_t * node,
 511              u32 next0, u32 thread_index, void *d, void *e)
 512 {
 513   snat_session_key_t sm0;
 514   u8 protocol;
 515   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 516   ip4_header_t *inner_ip0 = 0;
 517   void *l4_header = 0;
 518   icmp46_header_t *inner_icmp0;
 519   u8 dont_translate;
 520   u32 new_addr0, old_addr0;
 521   u16 old_id0, new_id0;
 522   ip_csum_t sum0;
 523   u16 checksum0;
 524   u32 next0_tmp;
 525
 526   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 527
 528   next0_tmp = sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0,
 529                                         &protocol, &sm0, &dont_translate, d,
 530                                         e);
 531   if (next0_tmp != ~0)
 532     next0 = next0_tmp;
 533   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
 534     goto out;
 535
 536   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 537     {
 538       sum0 = ip_incremental_checksum_buffer (sm->vlib_main, b0, (u8 *) icmp0 -
 539                                              (u8 *)
 540                                              vlib_buffer_get_current (b0),
 541                                              ntohs (ip0->length) -
 542                                              ip4_header_bytes (ip0), 0);
 543       checksum0 = ~ip_csum_fold (sum0);
 544       if (checksum0 != 0 && checksum0 != 0xffff)
 545         {
 546           next0 = SNAT_OUT2IN_NEXT_DROP;
 547           goto out;
 548         }
 549     }
 550
 551   old_addr0 = ip0->dst_address.as_u32;
 552   new_addr0 = ip0->dst_address.as_u32 = sm0.addr.as_u32;
 553   vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
 554
 555   sum0 = ip0->checksum;
 556   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 557                          dst_address /* changed member */ );
 558   ip0->checksum = ip_csum_fold (sum0);
 559
 560   if (icmp0->checksum == 0)
 561     icmp0->checksum = 0xffff;
 562
 563   if (!icmp_is_error_message (icmp0))
 564     {
 565       new_id0 = sm0.port;
 566       if (PREDICT_FALSE (new_id0 != echo0->identifier))
 567         {
 568           old_id0 = echo0->identifier;
 569           new_id0 = sm0.port;
 570           echo0->identifier = new_id0;
 571
 572           sum0 = icmp0->checksum;
 573           sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 574                                  identifier /* changed member */ );
 575           icmp0->checksum = ip_csum_fold (sum0);
 576         }
 577     }
 578   else
 579     {
 580       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 581       l4_header = ip4_next_header (inner_ip0);
 582
 583       if (!ip4_header_checksum_is_valid (inner_ip0))
 584         {
 585           next0 = SNAT_OUT2IN_NEXT_DROP;
 586           goto out;
 587         }
 588
 589       old_addr0 = inner_ip0->src_address.as_u32;
 590       inner_ip0->src_address = sm0.addr;
 591       new_addr0 = inner_ip0->src_address.as_u32;
 592
 593       sum0 = icmp0->checksum;
 594       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 595                              src_address /* changed member */ );
 596       icmp0->checksum = ip_csum_fold (sum0);
 597
 598       switch (protocol)
 599         {
 600         case SNAT_PROTOCOL_ICMP:
 601           inner_icmp0 = (icmp46_header_t *) l4_header;
 602           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 603
 604           old_id0 = inner_echo0->identifier;
 605           new_id0 = sm0.port;
 606           inner_echo0->identifier = new_id0;
 607
 608           sum0 = icmp0->checksum;
 609           sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 610                                  identifier);
 611           icmp0->checksum = ip_csum_fold (sum0);
 612           break;
 613         case SNAT_PROTOCOL_UDP:
 614         case SNAT_PROTOCOL_TCP:
 615           old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 616           new_id0 = sm0.port;
 617           ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 618
 619           sum0 = icmp0->checksum;
 620           sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 621                                  src_port);
 622           icmp0->checksum = ip_csum_fold (sum0);
 623           break;
 624         default:
 625           ASSERT (0);
 626         }
 627     }
 628
 629 out:
 630   return next0;
 631 }
 632
 633
 634 static inline u32
 635 icmp_out2in_slow_path (snat_main_t * sm,
 636                        vlib_buffer_t * b0,
 637                        ip4_header_t * ip0,
 638                        icmp46_header_t * icmp0,
 639                        u32 sw_if_index0,
 640                        u32 rx_fib_index0,
 641                        vlib_node_runtime_t * node,
 642                        u32 next0, f64 now,
 643                        u32 thread_index, snat_session_t ** p_s0)
 644 {
 645   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 646                        next0, thread_index, p_s0, 0);
 647   snat_session_t *s0 = *p_s0;
 648   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
 649     {
 650       /* Accounting */
 651       nat44_session_update_counters (s0, now,
 652                                      vlib_buffer_length_in_chain
 653                                      (sm->vlib_main, b0));
 654       /* Per-user LRU list maintenance */
 655       nat44_session_update_lru (sm, s0, thread_index);
 656     }
 657   return next0;
 658 }
 659
 660 static int
 661 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 662                              vlib_buffer_t * b,
 663                              ip4_header_t * ip, u32 rx_fib_index)
 664 {
 665   clib_bihash_kv_8_8_t kv, value;
 666   snat_static_mapping_t *m;
 667   snat_session_key_t m_key;
 668   u32 old_addr, new_addr;
 669   ip_csum_t sum;
 670
 671   m_key.addr = ip->dst_address;
 672   m_key.port = 0;
 673   m_key.protocol = 0;
 674   m_key.fib_index = 0;
 675   kv.key = m_key.as_u64;
 676   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 677     return 1;
 678
 679   m = pool_elt_at_index (sm->static_mappings, value.value);
 680
 681   old_addr = ip->dst_address.as_u32;
 682   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 683   sum = ip->checksum;
 684   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 685   ip->checksum = ip_csum_fold (sum);
 686
 687   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 688   return 0;
 689 }
 690
 691 static uword
 692 snat_out2in_node_fn (vlib_main_t * vm,
 693                      vlib_node_runtime_t * node, vlib_frame_t * frame)
 694 {
 695   u32 n_left_from, *from, *to_next;
 696   snat_out2in_next_t next_index;
 697   u32 pkts_processed = 0;
 698   snat_main_t *sm = &snat_main;
 699   f64 now = vlib_time_now (vm);
 700   u32 thread_index = vm->thread_index;
 701   u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
 702     0, fragments = 0;
 703
 704   from = vlib_frame_vector_args (frame);
 705   n_left_from = frame->n_vectors;
 706   next_index = node->cached_next_index;
 707
 708   while (n_left_from > 0)
 709     {
 710       u32 n_left_to_next;
 711
 712       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 713
 714       while (n_left_from >= 4 && n_left_to_next >= 2)
 715         {
 716           u32 bi0, bi1;
 717           vlib_buffer_t *b0, *b1;
 718           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 719           u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 720           u32 sw_if_index0, sw_if_index1;
 721           ip4_header_t *ip0, *ip1;
 722           ip_csum_t sum0, sum1;
 723           u32 new_addr0, old_addr0;
 724           u16 new_port0, old_port0;
 725           u32 new_addr1, old_addr1;
 726           u16 new_port1, old_port1;
 727           udp_header_t *udp0, *udp1;
 728           tcp_header_t *tcp0, *tcp1;
 729           icmp46_header_t *icmp0, *icmp1;
 730           snat_session_key_t key0, key1, sm0, sm1;
 731           u32 rx_fib_index0, rx_fib_index1;
 732           u32 proto0, proto1;
 733           snat_session_t *s0 = 0, *s1 = 0;
 734           clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
 735           u8 identity_nat0, identity_nat1;
 736
 737           /* Prefetch next iteration. */
 738           {
 739             vlib_buffer_t *p2, *p3;
 740
 741             p2 = vlib_get_buffer (vm, from[2]);
 742             p3 = vlib_get_buffer (vm, from[3]);
 743
 744             vlib_prefetch_buffer_header (p2, LOAD);
 745             vlib_prefetch_buffer_header (p3, LOAD);
 746
 747             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 748             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 749           }
 750
 751           /* speculatively enqueue b0 and b1 to the current next frame */
 752           to_next[0] = bi0 = from[0];
 753           to_next[1] = bi1 = from[1];
 754           from += 2;
 755           to_next += 2;
 756           n_left_from -= 2;
 757           n_left_to_next -= 2;
 758
 759           b0 = vlib_get_buffer (vm, bi0);
 760           b1 = vlib_get_buffer (vm, bi1);
 761
 762           vnet_buffer (b0)->snat.flags = 0;
 763           vnet_buffer (b1)->snat.flags = 0;
 764
 765           ip0 = vlib_buffer_get_current (b0);
 766           udp0 = ip4_next_header (ip0);
 767           tcp0 = (tcp_header_t *) udp0;
 768           icmp0 = (icmp46_header_t *) udp0;
 769
 770           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 771           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 772                                    sw_if_index0);
 773
 774           if (PREDICT_FALSE (ip0->ttl == 1))
 775             {
 776               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 777               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 778                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 779                                            0);
 780               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 781               goto trace0;
 782             }
 783
 784           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 785
 786           if (PREDICT_FALSE (proto0 == ~0))
 787             {
 788               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 789                 {
 790                   if (!sm->forwarding_enabled)
 791                     {
 792                       b0->error =
 793                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 794                       next0 = SNAT_OUT2IN_NEXT_DROP;
 795                     }
 796                 }
 797               other_packets++;
 798               goto trace0;
 799             }
 800
 801           if (PREDICT_FALSE (ip4_is_fragment (ip0)))
 802             {
 803               next0 = SNAT_OUT2IN_NEXT_REASS;
 804               fragments++;
 805               goto trace0;
 806             }
 807
 808           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 809             {
 810               next0 = icmp_out2in_slow_path
 811                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 812                  next0, now, thread_index, &s0);
 813               icmp_packets++;
 814               goto trace0;
 815             }
 816
 817           key0.addr = ip0->dst_address;
 818           key0.port = udp0->dst_port;
 819           key0.protocol = proto0;
 820           key0.fib_index = rx_fib_index0;
 821
 822           kv0.key = key0.as_u64;
 823
 824           if (clib_bihash_search_8_8
 825               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
 826             {
 827               /* Try to match static mapping by external address and port,
 828                  destination address and port in packet */
 829               if (snat_static_mapping_match
 830                   (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
 831                 {
 832                   /*
 833                    * Send DHCP packets to the ipv4 stack, or we won't
 834                    * be able to use dhcp client on the outside interface
 835                    */
 836                   if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
 837                                      && (udp0->dst_port ==
 838                                          clib_host_to_net_u16
 839                                          (UDP_DST_PORT_dhcp_to_client))))
 840                     {
 841                       vnet_feature_next (&next0, b0);
 842                       goto trace0;
 843                     }
 844
 845                   if (!sm->forwarding_enabled)
 846                     {
 847                       b0->error =
 848                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 849                       next0 = SNAT_OUT2IN_NEXT_DROP;
 850                     }
 851                   goto trace0;
 852                 }
 853
 854               if (PREDICT_FALSE (identity_nat0))
 855                 goto trace0;
 856
 857               /* Create session initiated by host from external network */
 858               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
 859                                                       thread_index, now);
 860               if (!s0)
 861                 {
 862                   next0 = SNAT_OUT2IN_NEXT_DROP;
 863                   goto trace0;
 864                 }
 865             }
 866           else
 867             s0 =
 868               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 869                                  value0.value);
 870
 871           old_addr0 = ip0->dst_address.as_u32;
 872           ip0->dst_address = s0->in2out.addr;
 873           new_addr0 = ip0->dst_address.as_u32;
 874           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 875
 876           sum0 = ip0->checksum;
 877           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 878                                  ip4_header_t,
 879                                  dst_address /* changed member */ );
 880           ip0->checksum = ip_csum_fold (sum0);
 881
 882           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 883             {
 884               old_port0 = tcp0->dst_port;
 885               tcp0->dst_port = s0->in2out.port;
 886               new_port0 = tcp0->dst_port;
 887
 888               sum0 = tcp0->checksum;
 889               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 890                                      ip4_header_t,
 891                                      dst_address /* changed member */ );
 892
 893               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 894                                      ip4_header_t /* cheat */ ,
 895                                      length /* changed member */ );
 896               tcp0->checksum = ip_csum_fold (sum0);
 897               tcp_packets++;
 898             }
 899           else
 900             {
 901               old_port0 = udp0->dst_port;
 902               udp0->dst_port = s0->in2out.port;
 903               udp0->checksum = 0;
 904               udp_packets++;
 905             }
 906
 907           /* Accounting */
 908           nat44_session_update_counters (s0, now,
 909                                          vlib_buffer_length_in_chain (vm,
 910                                                                       b0));
 911           /* Per-user LRU list maintenance */
 912           nat44_session_update_lru (sm, s0, thread_index);
 913         trace0:
 914
 915           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 916                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 917             {
 918               snat_out2in_trace_t *t =
 919                 vlib_add_trace (vm, node, b0, sizeof (*t));
 920               t->sw_if_index = sw_if_index0;
 921               t->next_index = next0;
 922               t->session_index = ~0;
 923               if (s0)
 924                 t->session_index =
 925                   s0 - sm->per_thread_data[thread_index].sessions;
 926             }
 927
 928           pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
 929
 930
 931           ip1 = vlib_buffer_get_current (b1);
 932           udp1 = ip4_next_header (ip1);
 933           tcp1 = (tcp_header_t *) udp1;
 934           icmp1 = (icmp46_header_t *) udp1;
 935
 936           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 937           rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 938                                    sw_if_index1);
 939
 940           if (PREDICT_FALSE (ip1->ttl == 1))
 941             {
 942               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 943               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 944                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 945                                            0);
 946               next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 947               goto trace1;
 948             }
 949
 950           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 951
 952           if (PREDICT_FALSE (proto1 == ~0))
 953             {
 954               if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
 955                 {
 956                   if (!sm->forwarding_enabled)
 957                     {
 958                       b1->error =
 959                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 960                       next1 = SNAT_OUT2IN_NEXT_DROP;
 961                     }
 962                 }
 963               other_packets++;
 964               goto trace1;
 965             }
 966
 967           if (PREDICT_FALSE (ip4_is_fragment (ip1)))
 968             {
 969               next1 = SNAT_OUT2IN_NEXT_REASS;
 970               fragments++;
 971               goto trace1;
 972             }
 973
 974           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
 975             {
 976               next1 = icmp_out2in_slow_path
 977                 (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
 978                  next1, now, thread_index, &s1);
 979               icmp_packets++;
 980               goto trace1;
 981             }
 982
 983           key1.addr = ip1->dst_address;
 984           key1.port = udp1->dst_port;
 985           key1.protocol = proto1;
 986           key1.fib_index = rx_fib_index1;
 987
 988           kv1.key = key1.as_u64;
 989
 990           if (clib_bihash_search_8_8
 991               (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
 992             {
 993               /* Try to match static mapping by external address and port,
 994                  destination address and port in packet */
 995               if (snat_static_mapping_match
 996                   (sm, key1, &sm1, 1, 0, 0, 0, 0, &identity_nat1))
 997                 {
 998                   /*
 999                    * Send DHCP packets to the ipv4 stack, or we won't
1000                    * be able to use dhcp client on the outside interface
1001                    */
1002                   if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_UDP
1003                                      && (udp1->dst_port ==
1004                                          clib_host_to_net_u16
1005                                          (UDP_DST_PORT_dhcp_to_client))))
1006                     {
1007                       vnet_feature_next (&next1, b1);
1008                       goto trace1;
1009                     }
1010
1011                   if (!sm->forwarding_enabled)
1012                     {
1013                       b1->error =
1014                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1015                       next1 = SNAT_OUT2IN_NEXT_DROP;
1016                     }
1017                   goto trace1;
1018                 }
1019
1020               if (PREDICT_FALSE (identity_nat1))
1021                 goto trace1;
1022
1023               /* Create session initiated by host from external network */
1024               s1 = create_session_for_static_mapping (sm, b1, sm1, key1, node,
1025                                                       thread_index, now);
1026               if (!s1)
1027                 {
1028                   next1 = SNAT_OUT2IN_NEXT_DROP;
1029                   goto trace1;
1030                 }
1031             }
1032           else
1033             s1 =
1034               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1035                                  value1.value);
1036
1037           old_addr1 = ip1->dst_address.as_u32;
1038           ip1->dst_address = s1->in2out.addr;
1039           new_addr1 = ip1->dst_address.as_u32;
1040           vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1041
1042           sum1 = ip1->checksum;
1043           sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1044                                  ip4_header_t,
1045                                  dst_address /* changed member */ );
1046           ip1->checksum = ip_csum_fold (sum1);
1047
1048           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
1049             {
1050               old_port1 = tcp1->dst_port;
1051               tcp1->dst_port = s1->in2out.port;
1052               new_port1 = tcp1->dst_port;
1053
1054               sum1 = tcp1->checksum;
1055               sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1056                                      ip4_header_t,
1057                                      dst_address /* changed member */ );
1058
1059               sum1 = ip_csum_update (sum1, old_port1, new_port1,
1060                                      ip4_header_t /* cheat */ ,
1061                                      length /* changed member */ );
1062               tcp1->checksum = ip_csum_fold (sum1);
1063               tcp_packets++;
1064             }
1065           else
1066             {
1067               old_port1 = udp1->dst_port;
1068               udp1->dst_port = s1->in2out.port;
1069               udp1->checksum = 0;
1070               udp_packets++;
1071             }
1072
1073           /* Accounting */
1074           nat44_session_update_counters (s1, now,
1075                                          vlib_buffer_length_in_chain (vm,
1076                                                                       b1));
1077           /* Per-user LRU list maintenance */
1078           nat44_session_update_lru (sm, s1, thread_index);
1079         trace1:
1080
1081           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1082                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1083             {
1084               snat_out2in_trace_t *t =
1085                 vlib_add_trace (vm, node, b1, sizeof (*t));
1086               t->sw_if_index = sw_if_index1;
1087               t->next_index = next1;
1088               t->session_index = ~0;
1089               if (s1)
1090                 t->session_index =
1091                   s1 - sm->per_thread_data[thread_index].sessions;
1092             }
1093
1094           pkts_processed += next1 == SNAT_OUT2IN_NEXT_LOOKUP;
1095
1096           /* verify speculative enqueues, maybe switch current next frame */
1097           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
1098                                            to_next, n_left_to_next,
1099                                            bi0, bi1, next0, next1);
1100         }
1101
1102       while (n_left_from > 0 && n_left_to_next > 0)
1103         {
1104           u32 bi0;
1105           vlib_buffer_t *b0;
1106           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1107           u32 sw_if_index0;
1108           ip4_header_t *ip0;
1109           ip_csum_t sum0;
1110           u32 new_addr0, old_addr0;
1111           u16 new_port0, old_port0;
1112           udp_header_t *udp0;
1113           tcp_header_t *tcp0;
1114           icmp46_header_t *icmp0;
1115           snat_session_key_t key0, sm0;
1116           u32 rx_fib_index0;
1117           u32 proto0;
1118           snat_session_t *s0 = 0;
1119           clib_bihash_kv_8_8_t kv0, value0;
1120           u8 identity_nat0;
1121
1122           /* speculatively enqueue b0 to the current next frame */
1123           bi0 = from[0];
1124           to_next[0] = bi0;
1125           from += 1;
1126           to_next += 1;
1127           n_left_from -= 1;
1128           n_left_to_next -= 1;
1129
1130           b0 = vlib_get_buffer (vm, bi0);
1131
1132           vnet_buffer (b0)->snat.flags = 0;
1133
1134           ip0 = vlib_buffer_get_current (b0);
1135           udp0 = ip4_next_header (ip0);
1136           tcp0 = (tcp_header_t *) udp0;
1137           icmp0 = (icmp46_header_t *) udp0;
1138
1139           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1140           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1141                                    sw_if_index0);
1142
1143           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1144
1145           if (PREDICT_FALSE (proto0 == ~0))
1146             {
1147               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1148                 {
1149                   if (!sm->forwarding_enabled)
1150                     {
1151                       b0->error =
1152                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1153                       next0 = SNAT_OUT2IN_NEXT_DROP;
1154                     }
1155                 }
1156               other_packets++;
1157               goto trace00;
1158             }
1159
1160           if (PREDICT_FALSE (ip0->ttl == 1))
1161             {
1162               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1163               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1164                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1165                                            0);
1166               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1167               goto trace00;
1168             }
1169
1170           if (PREDICT_FALSE (ip4_is_fragment (ip0)))
1171             {
1172               next0 = SNAT_OUT2IN_NEXT_REASS;
1173               fragments++;
1174               goto trace00;
1175             }
1176
1177           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1178             {
1179               next0 = icmp_out2in_slow_path
1180                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1181                  next0, now, thread_index, &s0);
1182               icmp_packets++;
1183               goto trace00;
1184             }
1185
1186           key0.addr = ip0->dst_address;
1187           key0.port = udp0->dst_port;
1188           key0.protocol = proto0;
1189           key0.fib_index = rx_fib_index0;
1190
1191           kv0.key = key0.as_u64;
1192
1193           if (clib_bihash_search_8_8
1194               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
1195             {
1196               /* Try to match static mapping by external address and port,
1197                  destination address and port in packet */
1198               if (snat_static_mapping_match
1199                   (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
1200                 {
1201                   /*
1202                    * Send DHCP packets to the ipv4 stack, or we won't
1203                    * be able to use dhcp client on the outside interface
1204                    */
1205                   if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
1206                                      && (udp0->dst_port ==
1207                                          clib_host_to_net_u16
1208                                          (UDP_DST_PORT_dhcp_to_client))))
1209                     {
1210                       vnet_feature_next (&next0, b0);
1211                       goto trace00;
1212                     }
1213
1214                   if (!sm->forwarding_enabled)
1215                     {
1216                       b0->error =
1217                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1218                       next0 = SNAT_OUT2IN_NEXT_DROP;
1219                     }
1220                   goto trace00;
1221                 }
1222
1223               if (PREDICT_FALSE (identity_nat0))
1224                 goto trace00;
1225
1226               /* Create session initiated by host from external network */
1227               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
1228                                                       thread_index, now);
1229               if (!s0)
1230                 {
1231                   next0 = SNAT_OUT2IN_NEXT_DROP;
1232                   goto trace00;
1233                 }
1234             }
1235           else
1236             s0 =
1237               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1238                                  value0.value);
1239
1240           old_addr0 = ip0->dst_address.as_u32;
1241           ip0->dst_address = s0->in2out.addr;
1242           new_addr0 = ip0->dst_address.as_u32;
1243           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1244
1245           sum0 = ip0->checksum;
1246           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1247                                  ip4_header_t,
1248                                  dst_address /* changed member */ );
1249           ip0->checksum = ip_csum_fold (sum0);
1250
1251           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1252             {
1253               old_port0 = tcp0->dst_port;
1254               tcp0->dst_port = s0->in2out.port;
1255               new_port0 = tcp0->dst_port;
1256
1257               sum0 = tcp0->checksum;
1258               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1259                                      ip4_header_t,
1260                                      dst_address /* changed member */ );
1261
1262               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1263                                      ip4_header_t /* cheat */ ,
1264                                      length /* changed member */ );
1265               tcp0->checksum = ip_csum_fold (sum0);
1266               tcp_packets++;
1267             }
1268           else
1269             {
1270               old_port0 = udp0->dst_port;
1271               udp0->dst_port = s0->in2out.port;
1272               udp0->checksum = 0;
1273               udp_packets++;
1274             }
1275
1276           /* Accounting */
1277           nat44_session_update_counters (s0, now,
1278                                          vlib_buffer_length_in_chain (vm,
1279                                                                       b0));
1280           /* Per-user LRU list maintenance */
1281           nat44_session_update_lru (sm, s0, thread_index);
1282         trace00:
1283
1284           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1285                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1286             {
1287               snat_out2in_trace_t *t =
1288                 vlib_add_trace (vm, node, b0, sizeof (*t));
1289               t->sw_if_index = sw_if_index0;
1290               t->next_index = next0;
1291               t->session_index = ~0;
1292               if (s0)
1293                 t->session_index =
1294                   s0 - sm->per_thread_data[thread_index].sessions;
1295             }
1296
1297           pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
1298
1299           /* verify speculative enqueue, maybe switch current next frame */
1300           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1301                                            to_next, n_left_to_next,
1302                                            bi0, next0);
1303         }
1304
1305       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1306     }
1307
1308   vlib_node_increment_counter (vm, snat_out2in_node.index,
1309                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1310                                pkts_processed);
1311   vlib_node_increment_counter (vm, snat_out2in_node.index,
1312                                SNAT_OUT2IN_ERROR_TCP_PACKETS, tcp_packets);
1313   vlib_node_increment_counter (vm, snat_out2in_node.index,
1314                                SNAT_OUT2IN_ERROR_UDP_PACKETS, udp_packets);
1315   vlib_node_increment_counter (vm, snat_out2in_node.index,
1316                                SNAT_OUT2IN_ERROR_ICMP_PACKETS, icmp_packets);
1317   vlib_node_increment_counter (vm, snat_out2in_node.index,
1318                                SNAT_OUT2IN_ERROR_OTHER_PACKETS,
1319                                other_packets);
1320   vlib_node_increment_counter (vm, snat_out2in_node.index,
1321                                SNAT_OUT2IN_ERROR_FRAGMENTS, fragments);
1322
1323   return frame->n_vectors;
1324 }
1325
1326 /* *INDENT-OFF* */
1327 VLIB_REGISTER_NODE (snat_out2in_node) = {
1328   .function = snat_out2in_node_fn,
1329   .name = "nat44-out2in",
1330   .vector_size = sizeof (u32),
1331   .format_trace = format_snat_out2in_trace,
1332   .type = VLIB_NODE_TYPE_INTERNAL,
1333
1334   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1335   .error_strings = snat_out2in_error_strings,
1336
1337   .runtime_data_bytes = sizeof (snat_runtime_t),
1338
1339   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1340
1341   /* edit / add dispositions here */
1342   .next_nodes = {
1343     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1344     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1345     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1346     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
1347   },
1348 };
1349 /* *INDENT-ON* */
1350
1351 VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_node, snat_out2in_node_fn);
1352
1353 static uword
1354 nat44_out2in_reass_node_fn (vlib_main_t * vm,
1355                             vlib_node_runtime_t * node, vlib_frame_t * frame)
1356 {
1357   u32 n_left_from, *from, *to_next;
1358   snat_out2in_next_t next_index;
1359   u32 pkts_processed = 0, cached_fragments = 0;
1360   snat_main_t *sm = &snat_main;
1361   f64 now = vlib_time_now (vm);
1362   u32 thread_index = vm->thread_index;
1363   snat_main_per_thread_data_t *per_thread_data =
1364     &sm->per_thread_data[thread_index];
1365   u32 *fragments_to_drop = 0;
1366   u32 *fragments_to_loopback = 0;
1367
1368   from = vlib_frame_vector_args (frame);
1369   n_left_from = frame->n_vectors;
1370   next_index = node->cached_next_index;
1371
1372   while (n_left_from > 0)
1373     {
1374       u32 n_left_to_next;
1375
1376       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1377
1378       while (n_left_from > 0 && n_left_to_next > 0)
1379         {
1380           u32 bi0, sw_if_index0, proto0, rx_fib_index0, new_addr0, old_addr0;
1381           vlib_buffer_t *b0;
1382           u32 next0;
1383           u8 cached0 = 0;
1384           ip4_header_t *ip0;
1385           nat_reass_ip4_t *reass0;
1386           udp_header_t *udp0;
1387           tcp_header_t *tcp0;
1388           icmp46_header_t *icmp0;
1389           snat_session_key_t key0, sm0;
1390           clib_bihash_kv_8_8_t kv0, value0;
1391           snat_session_t *s0 = 0;
1392           u16 old_port0, new_port0;
1393           ip_csum_t sum0;
1394           u8 identity_nat0;
1395
1396           /* speculatively enqueue b0 to the current next frame */
1397           bi0 = from[0];
1398           to_next[0] = bi0;
1399           from += 1;
1400           to_next += 1;
1401           n_left_from -= 1;
1402           n_left_to_next -= 1;
1403
1404           b0 = vlib_get_buffer (vm, bi0);
1405           next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1406
1407           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1408           rx_fib_index0 =
1409             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
1410                                                  sw_if_index0);
1411
1412           if (PREDICT_FALSE (nat_reass_is_drop_frag (0)))
1413             {
1414               next0 = SNAT_OUT2IN_NEXT_DROP;
1415               b0->error = node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT];
1416               goto trace0;
1417             }
1418
1419           ip0 = (ip4_header_t *) vlib_buffer_get_current (b0);
1420           udp0 = ip4_next_header (ip0);
1421           tcp0 = (tcp_header_t *) udp0;
1422           icmp0 = (icmp46_header_t *) udp0;
1423           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1424
1425           reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
1426                                                  ip0->dst_address,
1427                                                  ip0->fragment_id,
1428                                                  ip0->protocol,
1429                                                  1, &fragments_to_drop);
1430
1431           if (PREDICT_FALSE (!reass0))
1432             {
1433               next0 = SNAT_OUT2IN_NEXT_DROP;
1434               b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_REASS];
1435               nat_log_notice ("maximum reassemblies exceeded");
1436               goto trace0;
1437             }
1438
1439           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
1440             {
1441               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1442                 {
1443                   next0 = icmp_out2in_slow_path
1444                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1445                      next0, now, thread_index, &s0);
1446
1447                   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP))
1448                     {
1449                       if (s0)
1450                         reass0->sess_index = s0 - per_thread_data->sessions;
1451                       else
1452                         reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
1453                       reass0->thread_index = thread_index;
1454                       nat_ip4_reass_get_frags (reass0,
1455                                                &fragments_to_loopback);
1456                     }
1457
1458                   goto trace0;
1459                 }
1460
1461               key0.addr = ip0->dst_address;
1462               key0.port = udp0->dst_port;
1463               key0.protocol = proto0;
1464               key0.fib_index = rx_fib_index0;
1465               kv0.key = key0.as_u64;
1466
1467               if (clib_bihash_search_8_8
1468                   (&per_thread_data->out2in, &kv0, &value0))
1469                 {
1470                   /* Try to match static mapping by external address and port,
1471                      destination address and port in packet */
1472                   if (snat_static_mapping_match
1473                       (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
1474                     {
1475                       /*
1476                        * Send DHCP packets to the ipv4 stack, or we won't
1477                        * be able to use dhcp client on the outside interface
1478                        */
1479                       if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
1480                                          && (udp0->dst_port
1481                                              ==
1482                                              clib_host_to_net_u16
1483                                              (UDP_DST_PORT_dhcp_to_client))))
1484                         {
1485                           vnet_feature_next (&next0, b0);
1486                           goto trace0;
1487                         }
1488
1489                       if (!sm->forwarding_enabled)
1490                         {
1491                           b0->error =
1492                             node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1493                           next0 = SNAT_OUT2IN_NEXT_DROP;
1494                         }
1495                       else
1496                         {
1497                           reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
1498                           nat_ip4_reass_get_frags (reass0,
1499                                                    &fragments_to_loopback);
1500                         }
1501                       goto trace0;
1502                     }
1503
1504                   if (PREDICT_FALSE (identity_nat0))
1505                     goto trace0;
1506
1507                   /* Create session initiated by host from external network */
1508                   s0 =
1509                     create_session_for_static_mapping (sm, b0, sm0, key0,
1510                                                        node, thread_index,
1511                                                        now);
1512                   if (!s0)
1513                     {
1514                       b0->error =
1515                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1516                       next0 = SNAT_OUT2IN_NEXT_DROP;
1517                       goto trace0;
1518                     }
1519                   reass0->sess_index = s0 - per_thread_data->sessions;
1520                   reass0->thread_index = thread_index;
1521                 }
1522               else
1523                 {
1524                   s0 = pool_elt_at_index (per_thread_data->sessions,
1525                                           value0.value);
1526                   reass0->sess_index = value0.value;
1527                 }
1528               nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
1529             }
1530           else
1531             {
1532               if (reass0->flags & NAT_REASS_FLAG_ED_DONT_TRANSLATE)
1533                 goto trace0;
1534               if (PREDICT_FALSE (reass0->sess_index == (u32) ~ 0))
1535                 {
1536                   if (nat_ip4_reass_add_fragment
1537                       (thread_index, reass0, bi0, &fragments_to_drop))
1538                     {
1539                       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_FRAG];
1540                       nat_log_notice
1541                         ("maximum fragments per reassembly exceeded");
1542                       next0 = SNAT_OUT2IN_NEXT_DROP;
1543                       goto trace0;
1544                     }
1545                   cached0 = 1;
1546                   goto trace0;
1547                 }
1548               s0 = pool_elt_at_index (per_thread_data->sessions,
1549                                       reass0->sess_index);
1550             }
1551
1552           old_addr0 = ip0->dst_address.as_u32;
1553           ip0->dst_address = s0->in2out.addr;
1554           new_addr0 = ip0->dst_address.as_u32;
1555           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1556
1557           sum0 = ip0->checksum;
1558           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1559                                  ip4_header_t,
1560                                  dst_address /* changed member */ );
1561           ip0->checksum = ip_csum_fold (sum0);
1562
1563           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
1564             {
1565               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1566                 {
1567                   old_port0 = tcp0->dst_port;
1568                   tcp0->dst_port = s0->in2out.port;
1569                   new_port0 = tcp0->dst_port;
1570
1571                   sum0 = tcp0->checksum;
1572                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1573                                          ip4_header_t,
1574                                          dst_address /* changed member */ );
1575
1576                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1577                                          ip4_header_t /* cheat */ ,
1578                                          length /* changed member */ );
1579                   tcp0->checksum = ip_csum_fold (sum0);
1580                 }
1581               else
1582                 {
1583                   old_port0 = udp0->dst_port;
1584                   udp0->dst_port = s0->in2out.port;
1585                   udp0->checksum = 0;
1586                 }
1587             }
1588
1589           /* Accounting */
1590           nat44_session_update_counters (s0, now,
1591                                          vlib_buffer_length_in_chain (vm,
1592                                                                       b0));
1593           /* Per-user LRU list maintenance */
1594           nat44_session_update_lru (sm, s0, thread_index);
1595
1596         trace0:
1597           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1598                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1599             {
1600               nat44_reass_trace_t *t =
1601                 vlib_add_trace (vm, node, b0, sizeof (*t));
1602               t->cached = cached0;
1603               t->sw_if_index = sw_if_index0;
1604               t->next_index = next0;
1605             }
1606
1607           if (cached0)
1608             {
1609               n_left_to_next++;
1610               to_next--;
1611               cached_fragments++;
1612             }
1613           else
1614             {
1615               pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1616
1617               /* verify speculative enqueue, maybe switch current next frame */
1618               vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1619                                                to_next, n_left_to_next,
1620                                                bi0, next0);
1621             }
1622
1623           if (n_left_from == 0 && vec_len (fragments_to_loopback))
1624             {
1625               from = vlib_frame_vector_args (frame);
1626               u32 len = vec_len (fragments_to_loopback);
1627               if (len <= VLIB_FRAME_SIZE)
1628                 {
1629                   clib_memcpy_fast (from, fragments_to_loopback,
1630                                     sizeof (u32) * len);
1631                   n_left_from = len;
1632                   vec_reset_length (fragments_to_loopback);
1633                 }
1634               else
1635                 {
1636                   clib_memcpy_fast (from, fragments_to_loopback +
1637                                     (len - VLIB_FRAME_SIZE),
1638                                     sizeof (u32) * VLIB_FRAME_SIZE);
1639                   n_left_from = VLIB_FRAME_SIZE;
1640                   _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
1641                 }
1642             }
1643         }
1644
1645       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1646     }
1647
1648   vlib_node_increment_counter (vm, nat44_out2in_reass_node.index,
1649                                SNAT_OUT2IN_ERROR_PROCESSED_FRAGMENTS,
1650                                pkts_processed);
1651   vlib_node_increment_counter (vm, nat44_out2in_reass_node.index,
1652                                SNAT_OUT2IN_ERROR_CACHED_FRAGMENTS,
1653                                cached_fragments);
1654
1655   nat_send_all_to_node (vm, fragments_to_drop, node,
1656                         &node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT],
1657                         SNAT_OUT2IN_NEXT_DROP);
1658
1659   vec_free (fragments_to_drop);
1660   vec_free (fragments_to_loopback);
1661   return frame->n_vectors;
1662 }
1663
1664 /* *INDENT-OFF* */
1665 VLIB_REGISTER_NODE (nat44_out2in_reass_node) = {
1666   .function = nat44_out2in_reass_node_fn,
1667   .name = "nat44-out2in-reass",
1668   .vector_size = sizeof (u32),
1669   .format_trace = format_nat44_reass_trace,
1670   .type = VLIB_NODE_TYPE_INTERNAL,
1671
1672   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1673   .error_strings = snat_out2in_error_strings,
1674
1675   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1676
1677   /* edit / add dispositions here */
1678   .next_nodes = {
1679     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1680     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1681     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1682     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
1683   },
1684 };
1685 /* *INDENT-ON* */
1686
1687 VLIB_NODE_FUNCTION_MULTIARCH (nat44_out2in_reass_node,
1688                               nat44_out2in_reass_node_fn);
1689
1690 static uword
1691 snat_out2in_fast_node_fn (vlib_main_t * vm,
1692                           vlib_node_runtime_t * node, vlib_frame_t * frame)
1693 {
1694   u32 n_left_from, *from, *to_next;
1695   snat_out2in_next_t next_index;
1696   u32 pkts_processed = 0;
1697   snat_main_t *sm = &snat_main;
1698
1699   from = vlib_frame_vector_args (frame);
1700   n_left_from = frame->n_vectors;
1701   next_index = node->cached_next_index;
1702
1703   while (n_left_from > 0)
1704     {
1705       u32 n_left_to_next;
1706
1707       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1708
1709       while (n_left_from > 0 && n_left_to_next > 0)
1710         {
1711           u32 bi0;
1712           vlib_buffer_t *b0;
1713           u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1714           u32 sw_if_index0;
1715           ip4_header_t *ip0;
1716           ip_csum_t sum0;
1717           u32 new_addr0, old_addr0;
1718           u16 new_port0, old_port0;
1719           udp_header_t *udp0;
1720           tcp_header_t *tcp0;
1721           icmp46_header_t *icmp0;
1722           snat_session_key_t key0, sm0;
1723           u32 proto0;
1724           u32 rx_fib_index0;
1725
1726           /* speculatively enqueue b0 to the current next frame */
1727           bi0 = from[0];
1728           to_next[0] = bi0;
1729           from += 1;
1730           to_next += 1;
1731           n_left_from -= 1;
1732           n_left_to_next -= 1;
1733
1734           b0 = vlib_get_buffer (vm, bi0);
1735
1736           ip0 = vlib_buffer_get_current (b0);
1737           udp0 = ip4_next_header (ip0);
1738           tcp0 = (tcp_header_t *) udp0;
1739           icmp0 = (icmp46_header_t *) udp0;
1740
1741           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1742           rx_fib_index0 =
1743             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1744
1745           vnet_feature_next (&next0, b0);
1746
1747           if (PREDICT_FALSE (ip0->ttl == 1))
1748             {
1749               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1750               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1751                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1752                                            0);
1753               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1754               goto trace00;
1755             }
1756
1757           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1758
1759           if (PREDICT_FALSE (proto0 == ~0))
1760             goto trace00;
1761
1762           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1763             {
1764               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1765                                    rx_fib_index0, node, next0, ~0, 0, 0);
1766               goto trace00;
1767             }
1768
1769           key0.addr = ip0->dst_address;
1770           key0.port = udp0->dst_port;
1771           key0.fib_index = rx_fib_index0;
1772
1773           if (snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0, 0))
1774             {
1775               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1776               goto trace00;
1777             }
1778
1779           new_addr0 = sm0.addr.as_u32;
1780           new_port0 = sm0.port;
1781           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
1782           old_addr0 = ip0->dst_address.as_u32;
1783           ip0->dst_address.as_u32 = new_addr0;
1784
1785           sum0 = ip0->checksum;
1786           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1787                                  ip4_header_t,
1788                                  dst_address /* changed member */ );
1789           ip0->checksum = ip_csum_fold (sum0);
1790
1791           if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1792             {
1793               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1794                 {
1795                   old_port0 = tcp0->dst_port;
1796                   tcp0->dst_port = new_port0;
1797
1798                   sum0 = tcp0->checksum;
1799                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1800                                          ip4_header_t,
1801                                          dst_address /* changed member */ );
1802
1803                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1804                                          ip4_header_t /* cheat */ ,
1805                                          length /* changed member */ );
1806                   tcp0->checksum = ip_csum_fold (sum0);
1807                 }
1808               else
1809                 {
1810                   old_port0 = udp0->dst_port;
1811                   udp0->dst_port = new_port0;
1812                   udp0->checksum = 0;
1813                 }
1814             }
1815           else
1816             {
1817               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1818                 {
1819                   sum0 = tcp0->checksum;
1820                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1821                                          ip4_header_t,
1822                                          dst_address /* changed member */ );
1823
1824                   tcp0->checksum = ip_csum_fold (sum0);
1825                 }
1826             }
1827
1828         trace00:
1829
1830           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1831                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1832             {
1833               snat_out2in_trace_t *t =
1834                 vlib_add_trace (vm, node, b0, sizeof (*t));
1835               t->sw_if_index = sw_if_index0;
1836               t->next_index = next0;
1837             }
1838
1839           pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1840
1841           /* verify speculative enqueue, maybe switch current next frame */
1842           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1843                                            to_next, n_left_to_next,
1844                                            bi0, next0);
1845         }
1846
1847       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1848     }
1849
1850   vlib_node_increment_counter (vm, snat_out2in_fast_node.index,
1851                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1852                                pkts_processed);
1853   return frame->n_vectors;
1854 }
1855
1856 /* *INDENT-OFF* */
1857 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1858   .function = snat_out2in_fast_node_fn,
1859   .name = "nat44-out2in-fast",
1860   .vector_size = sizeof (u32),
1861   .format_trace = format_snat_out2in_fast_trace,
1862   .type = VLIB_NODE_TYPE_INTERNAL,
1863
1864   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1865   .error_strings = snat_out2in_error_strings,
1866
1867   .runtime_data_bytes = sizeof (snat_runtime_t),
1868
1869   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1870
1871   /* edit / add dispositions here */
1872   .next_nodes = {
1873     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1874     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1875     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1876     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
1877   },
1878 };
1879 /* *INDENT-ON* */
1880
1881 VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_fast_node,
1882                               snat_out2in_fast_node_fn);
1883
1884 /*
1885  * fd.io coding-style-patch-verification: ON
1886  *
1887  * Local Variables:
1888  * eval: (c-set-style "gnu")
1889  * End:
1890  */