src/plugins/nat/out2in_ed.c

   1 /*
   2  * Copyright (c) 2018 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 /**
  16  * @file
  17  * @brief 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 #include <vnet/ip/ip.h>
  24 #include <vnet/ethernet/ethernet.h>
  25 #include <vnet/fib/ip4_fib.h>
  26 #include <vnet/udp/udp.h>
  27 #include <vppinfra/error.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 #include <nat/nat_ha.h>
  34
  35 static char *nat_out2in_ed_error_strings[] = {
  36 #define _(sym,string) string,
  37   foreach_nat_out2in_ed_error
  38 #undef _
  39 };
  40
  41 typedef enum
  42 {
  43   NAT44_ED_OUT2IN_NEXT_DROP,
  44   NAT44_ED_OUT2IN_NEXT_LOOKUP,
  45   NAT44_ED_OUT2IN_NEXT_ICMP_ERROR,
  46   NAT44_ED_OUT2IN_NEXT_IN2OUT,
  47   NAT44_ED_OUT2IN_NEXT_SLOW_PATH,
  48   NAT44_ED_OUT2IN_NEXT_REASS,
  49   NAT44_ED_OUT2IN_N_NEXT,
  50 } nat44_ed_out2in_next_t;
  51
  52 typedef struct
  53 {
  54   u32 sw_if_index;
  55   u32 next_index;
  56   u32 session_index;
  57   u32 is_slow_path;
  58 } nat44_ed_out2in_trace_t;
  59
  60 static u8 *
  61 format_nat44_ed_out2in_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   nat44_ed_out2in_trace_t *t = va_arg (*args, nat44_ed_out2in_trace_t *);
  66   char *tag;
  67
  68   tag =
  69     t->is_slow_path ? "NAT44_OUT2IN_ED_SLOW_PATH" :
  70     "NAT44_OUT2IN_ED_FAST_PATH";
  71
  72   s = format (s, "%s: sw_if_index %d, next index %d, session %d", tag,
  73               t->sw_if_index, t->next_index, t->session_index);
  74
  75   return s;
  76 }
  77
  78 static inline u32
  79 icmp_out2in_ed_slow_path (snat_main_t * sm, vlib_buffer_t * b0,
  80                           ip4_header_t * ip0, icmp46_header_t * icmp0,
  81                           u32 sw_if_index0, u32 rx_fib_index0,
  82                           vlib_node_runtime_t * node, u32 next0, f64 now,
  83                           u32 thread_index, snat_session_t ** p_s0)
  84 {
  85   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
  86                        next0, thread_index, p_s0, 0);
  87   snat_session_t *s0 = *p_s0;
  88   if (PREDICT_TRUE (next0 != NAT44_ED_OUT2IN_NEXT_DROP && s0))
  89     {
  90       /* Accounting */
  91       nat44_session_update_counters (s0, now,
  92                                      vlib_buffer_length_in_chain
  93                                      (sm->vlib_main, b0), thread_index);
  94       /* Per-user LRU list maintenance */
  95       nat44_session_update_lru (sm, s0, thread_index);
  96     }
  97   return next0;
  98 }
  99
 100 #ifndef CLIB_MARCH_VARIANT
 101 int
 102 nat44_o2i_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg)
 103 {
 104   snat_main_t *sm = &snat_main;
 105   nat44_is_idle_session_ctx_t *ctx = arg;
 106   snat_session_t *s;
 107   u64 sess_timeout_time;
 108   nat_ed_ses_key_t ed_key;
 109   clib_bihash_kv_16_8_t ed_kv;
 110   int i;
 111   snat_address_t *a;
 112   snat_session_key_t key;
 113   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
 114                                                        ctx->thread_index);
 115
 116   s = pool_elt_at_index (tsm->sessions, kv->value);
 117   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
 118   if (ctx->now >= sess_timeout_time)
 119     {
 120       ed_key.l_addr = s->in2out.addr;
 121       ed_key.r_addr = s->ext_host_addr;
 122       ed_key.fib_index = s->in2out.fib_index;
 123       if (snat_is_unk_proto_session (s))
 124         {
 125           ed_key.proto = s->in2out.port;
 126           ed_key.r_port = 0;
 127           ed_key.l_port = 0;
 128         }
 129       else
 130         {
 131           ed_key.proto = snat_proto_to_ip_proto (s->in2out.protocol);
 132           ed_key.l_port = s->in2out.port;
 133           ed_key.r_port = s->ext_host_port;
 134         }
 135       if (is_twice_nat_session (s))
 136         {
 137           ed_key.r_addr = s->ext_host_nat_addr;
 138           ed_key.r_port = s->ext_host_nat_port;
 139         }
 140       ed_kv.key[0] = ed_key.as_u64[0];
 141       ed_kv.key[1] = ed_key.as_u64[1];
 142       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &ed_kv, 0))
 143         nat_elog_warn ("in2out_ed key del failed");
 144
 145       if (snat_is_unk_proto_session (s))
 146         goto delete;
 147
 148       snat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
 149                                            s->in2out.addr.as_u32,
 150                                            s->out2in.addr.as_u32,
 151                                            s->in2out.protocol,
 152                                            s->in2out.port,
 153                                            s->out2in.port,
 154                                            s->in2out.fib_index);
 155
 156       nat_syslog_nat44_sdel (s->user_index, s->in2out.fib_index,
 157                              &s->in2out.addr, s->in2out.port,
 158                              &s->ext_host_nat_addr, s->ext_host_nat_port,
 159                              &s->out2in.addr, s->out2in.port,
 160                              &s->ext_host_addr, s->ext_host_port,
 161                              s->in2out.protocol, is_twice_nat_session (s));
 162
 163       nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
 164                    s->ext_host_port, s->out2in.protocol, s->out2in.fib_index,
 165                    ctx->thread_index);
 166
 167       if (is_twice_nat_session (s))
 168         {
 169           for (i = 0; i < vec_len (sm->twice_nat_addresses); i++)
 170             {
 171               key.protocol = s->in2out.protocol;
 172               key.port = s->ext_host_nat_port;
 173               a = sm->twice_nat_addresses + i;
 174               if (a->addr.as_u32 == s->ext_host_nat_addr.as_u32)
 175                 {
 176                   snat_free_outside_address_and_port (sm->twice_nat_addresses,
 177                                                       ctx->thread_index,
 178                                                       &key);
 179                   break;
 180                 }
 181             }
 182         }
 183
 184       if (snat_is_session_static (s))
 185         goto delete;
 186
 187       snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
 188                                           &s->out2in);
 189     delete:
 190       nat44_delete_session (sm, s, ctx->thread_index);
 191       return 1;
 192     }
 193
 194   return 0;
 195 }
 196 #endif
 197
 198 static snat_session_t *
 199 create_session_for_static_mapping_ed (snat_main_t * sm,
 200                                       vlib_buffer_t * b,
 201                                       snat_session_key_t l_key,
 202                                       snat_session_key_t e_key,
 203                                       vlib_node_runtime_t * node,
 204                                       u32 thread_index,
 205                                       twice_nat_type_t twice_nat,
 206                                       lb_nat_type_t lb_nat, f64 now)
 207 {
 208   snat_session_t *s;
 209   snat_user_t *u;
 210   ip4_header_t *ip;
 211   udp_header_t *udp;
 212   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 213   clib_bihash_kv_16_8_t kv;
 214   snat_session_key_t eh_key;
 215   nat44_is_idle_session_ctx_t ctx;
 216
 217   if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 218     {
 219       b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
 220       nat_elog_notice ("maximum sessions exceeded");
 221       return 0;
 222     }
 223
 224   u = nat_user_get_or_create (sm, &l_key.addr, l_key.fib_index, thread_index);
 225   if (!u)
 226     {
 227       nat_elog_warn ("create NAT user failed");
 228       return 0;
 229     }
 230
 231   s = nat_ed_session_alloc (sm, u, thread_index, now);
 232   if (!s)
 233     {
 234       nat44_delete_user_with_no_session (sm, u, thread_index);
 235       nat_elog_warn ("create NAT session failed");
 236       return 0;
 237     }
 238
 239   ip = vlib_buffer_get_current (b);
 240   udp = ip4_next_header (ip);
 241
 242   s->ext_host_addr.as_u32 = ip->src_address.as_u32;
 243   s->ext_host_port = e_key.protocol == SNAT_PROTOCOL_ICMP ? 0 : udp->src_port;
 244   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 245   if (lb_nat)
 246     s->flags |= SNAT_SESSION_FLAG_LOAD_BALANCING;
 247   if (lb_nat == AFFINITY_LB_NAT)
 248     s->flags |= SNAT_SESSION_FLAG_AFFINITY;
 249   s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
 250   s->out2in = e_key;
 251   s->in2out = l_key;
 252   s->in2out.protocol = s->out2in.protocol;
 253   user_session_increment (sm, u, 1);
 254
 255   /* Add to lookup tables */
 256   make_ed_kv (&kv, &e_key.addr, &s->ext_host_addr, ip->protocol,
 257               e_key.fib_index, e_key.port, s->ext_host_port);
 258   kv.value = s - tsm->sessions;
 259   ctx.now = now;
 260   ctx.thread_index = thread_index;
 261   if (clib_bihash_add_or_overwrite_stale_16_8 (&tsm->out2in_ed, &kv,
 262                                                nat44_o2i_ed_is_idle_session_cb,
 263                                                &ctx))
 264     nat_elog_notice ("out2in-ed key add failed");
 265
 266   if (twice_nat == TWICE_NAT || (twice_nat == TWICE_NAT_SELF &&
 267                                  ip->src_address.as_u32 == l_key.addr.as_u32))
 268     {
 269       eh_key.protocol = e_key.protocol;
 270       if (snat_alloc_outside_address_and_port (sm->twice_nat_addresses, 0,
 271                                                thread_index, &eh_key,
 272                                                sm->port_per_thread,
 273                                                tsm->snat_thread_index))
 274         {
 275           b->error = node->errors[NAT_OUT2IN_ED_ERROR_OUT_OF_PORTS];
 276           nat44_delete_session (sm, s, thread_index);
 277           if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &kv, 0))
 278             nat_elog_notice ("out2in-ed key del failed");
 279           return 0;
 280         }
 281       s->ext_host_nat_addr.as_u32 = eh_key.addr.as_u32;
 282       s->ext_host_nat_port = eh_key.port;
 283       s->flags |= SNAT_SESSION_FLAG_TWICE_NAT;
 284       make_ed_kv (&kv, &l_key.addr, &s->ext_host_nat_addr, ip->protocol,
 285                   l_key.fib_index, l_key.port, s->ext_host_nat_port);
 286     }
 287   else
 288     {
 289       make_ed_kv (&kv, &l_key.addr, &s->ext_host_addr, ip->protocol,
 290                   l_key.fib_index, l_key.port, s->ext_host_port);
 291     }
 292   kv.value = s - tsm->sessions;
 293   if (clib_bihash_add_or_overwrite_stale_16_8 (&tsm->in2out_ed, &kv,
 294                                                nat44_i2o_ed_is_idle_session_cb,
 295                                                &ctx))
 296     nat_elog_notice ("in2out-ed key add failed");
 297
 298   snat_ipfix_logging_nat44_ses_create (thread_index,
 299                                        s->in2out.addr.as_u32,
 300                                        s->out2in.addr.as_u32,
 301                                        s->in2out.protocol,
 302                                        s->in2out.port,
 303                                        s->out2in.port, s->in2out.fib_index);
 304
 305   nat_syslog_nat44_sadd (s->user_index, s->in2out.fib_index,
 306                          &s->in2out.addr, s->in2out.port,
 307                          &s->ext_host_nat_addr, s->ext_host_nat_port,
 308                          &s->out2in.addr, s->out2in.port,
 309                          &s->ext_host_addr, s->ext_host_port,
 310                          s->in2out.protocol, is_twice_nat_session (s));
 311
 312   nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
 313                s->out2in.port, &s->ext_host_addr, s->ext_host_port,
 314                &s->ext_host_nat_addr, s->ext_host_nat_port,
 315                s->in2out.protocol, s->in2out.fib_index, s->flags,
 316                thread_index, 0);
 317
 318   return s;
 319 }
 320
 321 static int
 322 next_src_nat (snat_main_t * sm, ip4_header_t * ip, u8 proto, u16 src_port,
 323               u16 dst_port, u32 thread_index, u32 rx_fib_index)
 324 {
 325   clib_bihash_kv_16_8_t kv, value;
 326   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 327
 328   make_ed_kv (&kv, &ip->src_address, &ip->dst_address, proto,
 329               rx_fib_index, src_port, dst_port);
 330   if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
 331     return 1;
 332
 333   return 0;
 334 }
 335
 336 static void
 337 create_bypass_for_fwd (snat_main_t * sm, ip4_header_t * ip, u32 rx_fib_index,
 338                        u32 thread_index)
 339 {
 340   nat_ed_ses_key_t key;
 341   clib_bihash_kv_16_8_t kv, value;
 342   udp_header_t *udp;
 343   snat_user_t *u;
 344   snat_session_t *s = 0;
 345   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 346   f64 now = vlib_time_now (sm->vlib_main);
 347
 348   if (ip->protocol == IP_PROTOCOL_ICMP)
 349     {
 350       if (get_icmp_o2i_ed_key (ip, &key))
 351         return;
 352     }
 353   else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
 354     {
 355       udp = ip4_next_header (ip);
 356       key.r_addr = ip->src_address;
 357       key.l_addr = ip->dst_address;
 358       key.proto = ip->protocol;
 359       key.l_port = udp->dst_port;
 360       key.r_port = udp->src_port;
 361     }
 362   else
 363     {
 364       key.r_addr = ip->src_address;
 365       key.l_addr = ip->dst_address;
 366       key.proto = ip->protocol;
 367       key.l_port = key.r_port = 0;
 368     }
 369   key.fib_index = 0;
 370   kv.key[0] = key.as_u64[0];
 371   kv.key[1] = key.as_u64[1];
 372
 373   if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
 374     {
 375       s = pool_elt_at_index (tsm->sessions, value.value);
 376     }
 377   else
 378     {
 379       u32 proto;
 380
 381       if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 382         return;
 383
 384       u = nat_user_get_or_create (sm, &ip->dst_address, sm->inside_fib_index,
 385                                   thread_index);
 386       if (!u)
 387         {
 388           nat_elog_warn ("create NAT user failed");
 389           return;
 390         }
 391
 392       s = nat_ed_session_alloc (sm, u, thread_index, now);
 393       if (!s)
 394         {
 395           nat44_delete_user_with_no_session (sm, u, thread_index);
 396           nat_elog_warn ("create NAT session failed");
 397           return;
 398         }
 399
 400       proto = ip_proto_to_snat_proto (key.proto);
 401
 402       s->ext_host_addr = key.r_addr;
 403       s->ext_host_port = key.r_port;
 404       s->flags |= SNAT_SESSION_FLAG_FWD_BYPASS;
 405       s->out2in.addr = key.l_addr;
 406       s->out2in.port = key.l_port;
 407       s->out2in.protocol = proto;
 408       if (proto == ~0)
 409         {
 410           s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
 411           s->out2in.port = ip->protocol;
 412         }
 413       s->out2in.fib_index = 0;
 414       s->in2out = s->out2in;
 415       user_session_increment (sm, u, 0);
 416
 417       kv.value = s - tsm->sessions;
 418       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &kv, 1))
 419         nat_elog_notice ("in2out_ed key add failed");
 420     }
 421
 422   if (ip->protocol == IP_PROTOCOL_TCP)
 423     {
 424       tcp_header_t *tcp = ip4_next_header (ip);
 425       if (nat44_set_tcp_session_state_o2i (sm, s, tcp, thread_index))
 426         return;
 427     }
 428
 429   /* Accounting */
 430   nat44_session_update_counters (s, now, 0, thread_index);
 431   /* Per-user LRU list maintenance */
 432   nat44_session_update_lru (sm, s, thread_index);
 433 }
 434
 435 static inline void
 436 create_bypass_for_fwd_worker (snat_main_t * sm, ip4_header_t * ip,
 437                               u32 rx_fib_index)
 438 {
 439   ip4_header_t ip_wkr = {
 440     .src_address = ip->dst_address,
 441   };
 442   u32 thread_index = sm->worker_in2out_cb (&ip_wkr, rx_fib_index, 0);
 443
 444   create_bypass_for_fwd (sm, ip, rx_fib_index, thread_index);
 445 }
 446
 447 #ifndef CLIB_MARCH_VARIANT
 448 u32
 449 icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
 450                       u32 thread_index, vlib_buffer_t * b, ip4_header_t * ip,
 451                       u8 * p_proto, snat_session_key_t * p_value,
 452                       u8 * p_dont_translate, void *d, void *e)
 453 {
 454   u32 next = ~0, sw_if_index, rx_fib_index;
 455   icmp46_header_t *icmp;
 456   nat_ed_ses_key_t key;
 457   clib_bihash_kv_16_8_t kv, value;
 458   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 459   snat_session_t *s = 0;
 460   u8 dont_translate = 0, is_addr_only, identity_nat;
 461   snat_session_key_t e_key, l_key;
 462
 463   icmp = (icmp46_header_t *) ip4_next_header (ip);
 464   sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
 465   rx_fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 466
 467   if (get_icmp_o2i_ed_key (ip, &key))
 468     {
 469       b->error = node->errors[NAT_OUT2IN_ED_ERROR_UNSUPPORTED_PROTOCOL];
 470       next = NAT44_ED_OUT2IN_NEXT_DROP;
 471       goto out;
 472     }
 473   key.fib_index = rx_fib_index;
 474   kv.key[0] = key.as_u64[0];
 475   kv.key[1] = key.as_u64[1];
 476
 477   if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv, &value))
 478     {
 479       /* Try to match static mapping */
 480       e_key.addr = ip->dst_address;
 481       e_key.port = key.l_port;
 482       e_key.protocol = ip_proto_to_snat_proto (key.proto);
 483       e_key.fib_index = rx_fib_index;
 484       if (snat_static_mapping_match
 485           (sm, e_key, &l_key, 1, &is_addr_only, 0, 0, 0, &identity_nat))
 486         {
 487           if (!sm->forwarding_enabled)
 488             {
 489               /* Don't NAT packet aimed at the intfc address */
 490               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index,
 491                                                     ip->dst_address.as_u32)))
 492                 {
 493                   dont_translate = 1;
 494                   goto out;
 495                 }
 496               b->error = node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
 497               next = NAT44_ED_OUT2IN_NEXT_DROP;
 498               goto out;
 499             }
 500           else
 501             {
 502               dont_translate = 1;
 503               if (next_src_nat (sm, ip, key.proto, key.l_port, key.r_port,
 504                                 thread_index, rx_fib_index))
 505                 {
 506                   next = NAT44_ED_OUT2IN_NEXT_IN2OUT;
 507                   goto out;
 508                 }
 509               if (sm->num_workers > 1)
 510                 create_bypass_for_fwd_worker (sm, ip, rx_fib_index);
 511               else
 512                 create_bypass_for_fwd (sm, ip, rx_fib_index, thread_index);
 513               goto out;
 514             }
 515         }
 516
 517       if (PREDICT_FALSE (icmp->type != ICMP4_echo_reply &&
 518                          (icmp->type != ICMP4_echo_request || !is_addr_only)))
 519         {
 520           b->error = node->errors[NAT_OUT2IN_ED_ERROR_BAD_ICMP_TYPE];
 521           next = NAT44_ED_OUT2IN_NEXT_DROP;
 522           goto out;
 523         }
 524
 525       if (PREDICT_FALSE (identity_nat))
 526         {
 527           dont_translate = 1;
 528           goto out;
 529         }
 530
 531       /* Create session initiated by host from external network */
 532       s = create_session_for_static_mapping_ed (sm, b, l_key, e_key, node,
 533                                                 thread_index, 0, 0,
 534                                                 vlib_time_now
 535                                                 (sm->vlib_main));
 536
 537       if (!s)
 538         {
 539           next = NAT44_ED_OUT2IN_NEXT_DROP;
 540           goto out;
 541         }
 542     }
 543   else
 544     {
 545       if (PREDICT_FALSE (icmp->type != ICMP4_echo_reply &&
 546                          icmp->type != ICMP4_echo_request &&
 547                          !icmp_is_error_message (icmp)))
 548         {
 549           b->error = node->errors[NAT_OUT2IN_ED_ERROR_BAD_ICMP_TYPE];
 550           next = NAT44_ED_OUT2IN_NEXT_DROP;
 551           goto out;
 552         }
 553
 554       s = pool_elt_at_index (tsm->sessions, value.value);
 555     }
 556
 557   *p_proto = ip_proto_to_snat_proto (key.proto);
 558 out:
 559   if (s)
 560     *p_value = s->in2out;
 561   *p_dont_translate = dont_translate;
 562   if (d)
 563     *(snat_session_t **) d = s;
 564   return next;
 565 }
 566 #endif
 567
 568 static snat_session_t *
 569 nat44_ed_out2in_unknown_proto (snat_main_t * sm,
 570                                vlib_buffer_t * b,
 571                                ip4_header_t * ip,
 572                                u32 rx_fib_index,
 573                                u32 thread_index,
 574                                f64 now,
 575                                vlib_main_t * vm, vlib_node_runtime_t * node)
 576 {
 577   clib_bihash_kv_8_8_t kv, value;
 578   clib_bihash_kv_16_8_t s_kv, s_value;
 579   snat_static_mapping_t *m;
 580   u32 old_addr, new_addr;
 581   ip_csum_t sum;
 582   snat_session_t *s;
 583   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 584   snat_user_t *u;
 585
 586   old_addr = ip->dst_address.as_u32;
 587
 588   make_ed_kv (&s_kv, &ip->dst_address, &ip->src_address, ip->protocol,
 589               rx_fib_index, 0, 0);
 590
 591   if (!clib_bihash_search_16_8 (&tsm->out2in_ed, &s_kv, &s_value))
 592     {
 593       s = pool_elt_at_index (tsm->sessions, s_value.value);
 594       new_addr = ip->dst_address.as_u32 = s->in2out.addr.as_u32;
 595     }
 596   else
 597     {
 598       if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 599         {
 600           b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
 601           nat_elog_notice ("maximum sessions exceeded");
 602           return 0;
 603         }
 604
 605       make_sm_kv (&kv, &ip->dst_address, 0, 0, 0);
 606       if (clib_bihash_search_8_8
 607           (&sm->static_mapping_by_external, &kv, &value))
 608         {
 609           b->error = node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
 610           return 0;
 611         }
 612
 613       m = pool_elt_at_index (sm->static_mappings, value.value);
 614
 615       new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 616
 617       u = nat_user_get_or_create (sm, &m->local_addr, m->fib_index,
 618                                   thread_index);
 619       if (!u)
 620         {
 621           nat_elog_warn ("create NAT user failed");
 622           return 0;
 623         }
 624
 625       /* Create a new session */
 626       s = nat_ed_session_alloc (sm, u, thread_index, now);
 627       if (!s)
 628         {
 629           nat44_delete_user_with_no_session (sm, u, thread_index);
 630           nat_elog_warn ("create NAT session failed");
 631           return 0;
 632         }
 633
 634       s->ext_host_addr.as_u32 = ip->src_address.as_u32;
 635       s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
 636       s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 637       s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
 638       s->out2in.addr.as_u32 = old_addr;
 639       s->out2in.fib_index = rx_fib_index;
 640       s->in2out.addr.as_u32 = new_addr;
 641       s->in2out.fib_index = m->fib_index;
 642       s->in2out.port = s->out2in.port = ip->protocol;
 643       user_session_increment (sm, u, 1);
 644
 645       /* Add to lookup tables */
 646       s_kv.value = s - tsm->sessions;
 647       if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &s_kv, 1))
 648         nat_elog_notice ("out2in key add failed");
 649
 650       make_ed_kv (&s_kv, &ip->dst_address, &ip->src_address, ip->protocol,
 651                   m->fib_index, 0, 0);
 652       s_kv.value = s - tsm->sessions;
 653       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &s_kv, 1))
 654         nat_elog_notice ("in2out key add failed");
 655     }
 656
 657   /* Update IP checksum */
 658   sum = ip->checksum;
 659   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 660   ip->checksum = ip_csum_fold (sum);
 661
 662   vnet_buffer (b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
 663
 664   /* Accounting */
 665   nat44_session_update_counters (s, now, vlib_buffer_length_in_chain (vm, b),
 666                                  thread_index);
 667   /* Per-user LRU list maintenance */
 668   nat44_session_update_lru (sm, s, thread_index);
 669
 670   return s;
 671 }
 672
 673 static inline uword
 674 nat44_ed_out2in_node_fn_inline (vlib_main_t * vm,
 675                                 vlib_node_runtime_t * node,
 676                                 vlib_frame_t * frame, int is_slow_path)
 677 {
 678   u32 n_left_from, *from, *to_next, pkts_processed = 0, stats_node_index;
 679   nat44_ed_out2in_next_t next_index;
 680   snat_main_t *sm = &snat_main;
 681   f64 now = vlib_time_now (vm);
 682   u32 thread_index = vm->thread_index;
 683   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 684   u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
 685     0, fragments = 0;
 686
 687   stats_node_index = is_slow_path ? sm->ed_out2in_slowpath_node_index :
 688     sm->ed_out2in_node_index;
 689
 690   from = vlib_frame_vector_args (frame);
 691   n_left_from = frame->n_vectors;
 692   next_index = node->cached_next_index;
 693
 694   while (n_left_from > 0)
 695     {
 696       u32 n_left_to_next;
 697
 698       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 699
 700       while (n_left_from >= 4 && n_left_to_next >= 2)
 701         {
 702           u32 bi0, bi1;
 703           vlib_buffer_t *b0, *b1;
 704           u32 next0, sw_if_index0, rx_fib_index0, proto0, old_addr0,
 705             new_addr0;
 706           u32 next1, sw_if_index1, rx_fib_index1, proto1, old_addr1,
 707             new_addr1;
 708           u16 old_port0, new_port0, old_port1, new_port1;
 709           ip4_header_t *ip0, *ip1;
 710           udp_header_t *udp0, *udp1;
 711           tcp_header_t *tcp0, *tcp1;
 712           icmp46_header_t *icmp0, *icmp1;
 713           snat_session_t *s0 = 0, *s1 = 0;
 714           clib_bihash_kv_16_8_t kv0, value0, kv1, value1;
 715           ip_csum_t sum0, sum1;
 716           snat_session_key_t e_key0, l_key0, e_key1, l_key1;
 717           lb_nat_type_t lb_nat0, lb_nat1;
 718           twice_nat_type_t twice_nat0, twice_nat1;
 719           u8 identity_nat0, identity_nat1;
 720
 721           /* Prefetch next iteration. */
 722           {
 723             vlib_buffer_t *p2, *p3;
 724
 725             p2 = vlib_get_buffer (vm, from[2]);
 726             p3 = vlib_get_buffer (vm, from[3]);
 727
 728             vlib_prefetch_buffer_header (p2, LOAD);
 729             vlib_prefetch_buffer_header (p3, LOAD);
 730
 731             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 732             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 733           }
 734
 735           /* speculatively enqueue b0 and b1 to the current next frame */
 736           to_next[0] = bi0 = from[0];
 737           to_next[1] = bi1 = from[1];
 738           from += 2;
 739           to_next += 2;
 740           n_left_from -= 2;
 741           n_left_to_next -= 2;
 742
 743           b0 = vlib_get_buffer (vm, bi0);
 744           b1 = vlib_get_buffer (vm, bi1);
 745
 746           next0 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
 747           vnet_buffer (b0)->snat.flags = 0;
 748           ip0 = vlib_buffer_get_current (b0);
 749
 750           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 751           rx_fib_index0 =
 752             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
 753                                                  sw_if_index0);
 754
 755           if (PREDICT_FALSE (ip0->ttl == 1))
 756             {
 757               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 758               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 759                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 760                                            0);
 761               next0 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
 762               goto trace00;
 763             }
 764
 765           udp0 = ip4_next_header (ip0);
 766           tcp0 = (tcp_header_t *) udp0;
 767           icmp0 = (icmp46_header_t *) udp0;
 768           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 769
 770           if (is_slow_path)
 771             {
 772               if (PREDICT_FALSE (proto0 == ~0))
 773                 {
 774                   s0 =
 775                     nat44_ed_out2in_unknown_proto (sm, b0, ip0, rx_fib_index0,
 776                                                    thread_index, now, vm,
 777                                                    node);
 778                   other_packets++;
 779                   if (!sm->forwarding_enabled)
 780                     {
 781                       if (!s0)
 782                         next0 = NAT44_ED_OUT2IN_NEXT_DROP;
 783                       goto trace00;
 784                     }
 785                 }
 786
 787               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 788                 {
 789                   next0 = icmp_out2in_ed_slow_path
 790                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 791                      next0, now, thread_index, &s0);
 792                   icmp_packets++;
 793                   goto trace00;
 794                 }
 795             }
 796           else
 797             {
 798               if (PREDICT_FALSE (proto0 == ~0))
 799                 {
 800                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
 801                   goto trace00;
 802                 }
 803
 804               if (ip4_is_fragment (ip0))
 805                 {
 806                   next0 = NAT44_ED_OUT2IN_NEXT_REASS;
 807                   fragments++;
 808                   goto trace00;
 809                 }
 810
 811               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 812                 {
 813                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
 814                   goto trace00;
 815                 }
 816             }
 817
 818           make_ed_kv (&kv0, &ip0->dst_address, &ip0->src_address,
 819                       ip0->protocol, rx_fib_index0, udp0->dst_port,
 820                       udp0->src_port);
 821
 822           if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv0, &value0))
 823             {
 824               if (is_slow_path)
 825                 {
 826                   /* Try to match static mapping by external address and port,
 827                      destination address and port in packet */
 828                   e_key0.addr = ip0->dst_address;
 829                   e_key0.port = udp0->dst_port;
 830                   e_key0.protocol = proto0;
 831                   e_key0.fib_index = rx_fib_index0;
 832                   if (snat_static_mapping_match (sm, e_key0, &l_key0, 1, 0,
 833                                                  &twice_nat0, &lb_nat0,
 834                                                  &ip0->src_address,
 835                                                  &identity_nat0))
 836                     {
 837                       /*
 838                        * Send DHCP packets to the ipv4 stack, or we won't
 839                        * be able to use dhcp client on the outside interface
 840                        */
 841                       if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
 842                                          && (udp0->dst_port ==
 843                                              clib_host_to_net_u16
 844                                              (UDP_DST_PORT_dhcp_to_client))))
 845                         {
 846                           vnet_feature_next (&next0, b0);
 847                           goto trace00;
 848                         }
 849
 850                       if (!sm->forwarding_enabled)
 851                         {
 852                           b0->error =
 853                             node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
 854                           next0 = NAT44_ED_OUT2IN_NEXT_DROP;
 855                         }
 856                       else
 857                         {
 858                           if (next_src_nat (sm, ip0, ip0->protocol,
 859                                             udp0->src_port, udp0->dst_port,
 860                                             thread_index, rx_fib_index0))
 861                             {
 862                               next0 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
 863                               goto trace00;
 864                             }
 865                           if (sm->num_workers > 1)
 866                             create_bypass_for_fwd_worker (sm, ip0,
 867                                                           rx_fib_index0);
 868                           else
 869                             create_bypass_for_fwd (sm, ip0, rx_fib_index0,
 870                                                    thread_index);
 871                         }
 872                       goto trace00;
 873                     }
 874
 875                   if (PREDICT_FALSE (identity_nat0))
 876                     goto trace00;
 877
 878                   if ((proto0 == SNAT_PROTOCOL_TCP) && !tcp_is_init (tcp0))
 879                     {
 880                       b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
 881                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
 882                       goto trace00;
 883                     }
 884
 885                   /* Create session initiated by host from external network */
 886                   s0 = create_session_for_static_mapping_ed (sm, b0, l_key0,
 887                                                              e_key0, node,
 888                                                              thread_index,
 889                                                              twice_nat0,
 890                                                              lb_nat0, now);
 891
 892                   if (!s0)
 893                     {
 894                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
 895                       goto trace00;
 896                     }
 897                 }
 898               else
 899                 {
 900                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
 901                   goto trace00;
 902                 }
 903             }
 904           else
 905             {
 906               s0 = pool_elt_at_index (tsm->sessions, value0.value);
 907             }
 908
 909           old_addr0 = ip0->dst_address.as_u32;
 910           new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
 911           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 912
 913           sum0 = ip0->checksum;
 914           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 915                                  dst_address);
 916           if (PREDICT_FALSE (is_twice_nat_session (s0)))
 917             sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
 918                                    s0->ext_host_nat_addr.as_u32, ip4_header_t,
 919                                    src_address);
 920           ip0->checksum = ip_csum_fold (sum0);
 921
 922           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 923             {
 924               old_port0 = tcp0->dst_port;
 925               new_port0 = tcp0->dst_port = s0->in2out.port;
 926
 927               sum0 = tcp0->checksum;
 928               sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 929                                      dst_address);
 930               sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
 931                                      length);
 932               if (is_twice_nat_session (s0))
 933                 {
 934                   sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
 935                                          s0->ext_host_nat_addr.as_u32,
 936                                          ip4_header_t, dst_address);
 937                   sum0 = ip_csum_update (sum0, tcp0->src_port,
 938                                          s0->ext_host_nat_port, ip4_header_t,
 939                                          length);
 940                   tcp0->src_port = s0->ext_host_nat_port;
 941                   ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
 942                 }
 943               tcp0->checksum = ip_csum_fold (sum0);
 944               tcp_packets++;
 945               if (nat44_set_tcp_session_state_o2i
 946                   (sm, s0, tcp0, thread_index))
 947                 goto trace00;
 948             }
 949           else
 950             {
 951               udp0->dst_port = s0->in2out.port;
 952               if (is_twice_nat_session (s0))
 953                 {
 954                   udp0->src_port = s0->ext_host_nat_port;
 955                   ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
 956                 }
 957               udp0->checksum = 0;
 958               udp_packets++;
 959             }
 960
 961           /* Accounting */
 962           nat44_session_update_counters (s0, now,
 963                                          vlib_buffer_length_in_chain (vm, b0),
 964                                          thread_index);
 965           /* Per-user LRU list maintenance */
 966           nat44_session_update_lru (sm, s0, thread_index);
 967
 968         trace00:
 969           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 970                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 971             {
 972               nat44_ed_out2in_trace_t *t =
 973                 vlib_add_trace (vm, node, b0, sizeof (*t));
 974               t->is_slow_path = is_slow_path;
 975               t->sw_if_index = sw_if_index0;
 976               t->next_index = next0;
 977               t->session_index = ~0;
 978               if (s0)
 979                 t->session_index = s0 - tsm->sessions;
 980             }
 981
 982           pkts_processed += next0 == NAT44_ED_OUT2IN_NEXT_LOOKUP;
 983
 984           next1 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
 985           vnet_buffer (b1)->snat.flags = 0;
 986           ip1 = vlib_buffer_get_current (b1);
 987
 988           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 989           rx_fib_index1 =
 990             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
 991                                                  sw_if_index1);
 992
 993           if (PREDICT_FALSE (ip1->ttl == 1))
 994             {
 995               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 996               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 997                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 998                                            0);
 999               next1 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
1000               goto trace01;
1001             }
1002
1003           udp1 = ip4_next_header (ip1);
1004           tcp1 = (tcp_header_t *) udp1;
1005           icmp1 = (icmp46_header_t *) udp1;
1006           proto1 = ip_proto_to_snat_proto (ip1->protocol);
1007
1008           if (is_slow_path)
1009             {
1010               if (PREDICT_FALSE (proto1 == ~0))
1011                 {
1012                   s1 =
1013                     nat44_ed_out2in_unknown_proto (sm, b1, ip1, rx_fib_index1,
1014                                                    thread_index, now, vm,
1015                                                    node);
1016                   other_packets++;
1017                   if (!sm->forwarding_enabled)
1018                     {
1019                       if (!s1)
1020                         next1 = NAT44_ED_OUT2IN_NEXT_DROP;
1021                       goto trace01;
1022                     }
1023                 }
1024
1025               if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
1026                 {
1027                   next1 = icmp_out2in_ed_slow_path
1028                     (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
1029                      next1, now, thread_index, &s1);
1030                   icmp_packets++;
1031                   goto trace01;
1032                 }
1033             }
1034           else
1035             {
1036               if (PREDICT_FALSE (proto1 == ~0))
1037                 {
1038                   next1 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1039                   goto trace01;
1040                 }
1041
1042               if (ip4_is_fragment (ip1))
1043                 {
1044                   next1 = NAT44_ED_OUT2IN_NEXT_REASS;
1045                   fragments++;
1046                   goto trace01;
1047                 }
1048
1049               if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
1050                 {
1051                   next1 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1052                   goto trace01;
1053                 }
1054             }
1055
1056           make_ed_kv (&kv1, &ip1->dst_address, &ip1->src_address,
1057                       ip1->protocol, rx_fib_index1, udp1->dst_port,
1058                       udp1->src_port);
1059
1060           if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv1, &value1))
1061             {
1062               if (is_slow_path)
1063                 {
1064                   /* Try to match static mapping by external address and port,
1065                      destination address and port in packet */
1066                   e_key1.addr = ip1->dst_address;
1067                   e_key1.port = udp1->dst_port;
1068                   e_key1.protocol = proto1;
1069                   e_key1.fib_index = rx_fib_index1;
1070                   if (snat_static_mapping_match (sm, e_key1, &l_key1, 1, 0,
1071                                                  &twice_nat1, &lb_nat1,
1072                                                  &ip1->src_address,
1073                                                  &identity_nat1))
1074                     {
1075                       /*
1076                        * Send DHCP packets to the ipv4 stack, or we won't
1077                        * be able to use dhcp client on the outside interface
1078                        */
1079                       if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_UDP
1080                                          && (udp1->dst_port ==
1081                                              clib_host_to_net_u16
1082                                              (UDP_DST_PORT_dhcp_to_client))))
1083                         {
1084                           vnet_feature_next (&next1, b1);
1085                           goto trace01;
1086                         }
1087
1088                       if (!sm->forwarding_enabled)
1089                         {
1090                           b1->error =
1091                             node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
1092                           next1 = NAT44_ED_OUT2IN_NEXT_DROP;
1093                         }
1094                       else
1095                         {
1096                           if (next_src_nat (sm, ip1, ip1->protocol,
1097                                             udp1->src_port, udp1->dst_port,
1098                                             thread_index, rx_fib_index1))
1099                             {
1100                               next1 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
1101                               goto trace01;
1102                             }
1103                           if (sm->num_workers > 1)
1104                             create_bypass_for_fwd_worker (sm, ip1,
1105                                                           rx_fib_index1);
1106                           else
1107                             create_bypass_for_fwd (sm, ip1, rx_fib_index1,
1108                                                    thread_index);
1109                         }
1110                       goto trace01;
1111                     }
1112
1113                   if (PREDICT_FALSE (identity_nat1))
1114                     goto trace01;
1115
1116                   if ((proto1 == SNAT_PROTOCOL_TCP) && !tcp_is_init (tcp1))
1117                     {
1118                       b1->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
1119                       next1 = NAT44_ED_OUT2IN_NEXT_DROP;
1120                       goto trace01;
1121                     }
1122
1123                   /* Create session initiated by host from external network */
1124                   s1 = create_session_for_static_mapping_ed (sm, b1, l_key1,
1125                                                              e_key1, node,
1126                                                              thread_index,
1127                                                              twice_nat1,
1128                                                              lb_nat1, now);
1129
1130                   if (!s1)
1131                     {
1132                       next1 = NAT44_ED_OUT2IN_NEXT_DROP;
1133                       goto trace01;
1134                     }
1135                 }
1136               else
1137                 {
1138                   next1 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1139                   goto trace01;
1140                 }
1141             }
1142           else
1143             {
1144               s1 = pool_elt_at_index (tsm->sessions, value1.value);
1145             }
1146
1147           old_addr1 = ip1->dst_address.as_u32;
1148           new_addr1 = ip1->dst_address.as_u32 = s1->in2out.addr.as_u32;
1149           vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1150
1151           sum1 = ip1->checksum;
1152           sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t,
1153                                  dst_address);
1154           if (PREDICT_FALSE (is_twice_nat_session (s1)))
1155             sum1 = ip_csum_update (sum1, ip1->src_address.as_u32,
1156                                    s1->ext_host_nat_addr.as_u32, ip4_header_t,
1157                                    src_address);
1158           ip1->checksum = ip_csum_fold (sum1);
1159
1160           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
1161             {
1162               old_port1 = tcp1->dst_port;
1163               new_port1 = tcp1->dst_port = s1->in2out.port;
1164
1165               sum1 = tcp1->checksum;
1166               sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t,
1167                                      dst_address);
1168               sum1 = ip_csum_update (sum1, old_port1, new_port1, ip4_header_t,
1169                                      length);
1170               if (is_twice_nat_session (s1))
1171                 {
1172                   sum1 = ip_csum_update (sum1, ip1->src_address.as_u32,
1173                                          s1->ext_host_nat_addr.as_u32,
1174                                          ip4_header_t, dst_address);
1175                   sum1 = ip_csum_update (sum1, tcp1->src_port,
1176                                          s1->ext_host_nat_port, ip4_header_t,
1177                                          length);
1178                   tcp1->src_port = s1->ext_host_nat_port;
1179                   ip1->src_address.as_u32 = s1->ext_host_nat_addr.as_u32;
1180                 }
1181               tcp1->checksum = ip_csum_fold (sum1);
1182               tcp_packets++;
1183               if (nat44_set_tcp_session_state_o2i
1184                   (sm, s1, tcp1, thread_index))
1185                 goto trace01;
1186             }
1187           else
1188             {
1189               udp1->dst_port = s1->in2out.port;
1190               if (is_twice_nat_session (s1))
1191                 {
1192                   udp1->src_port = s1->ext_host_nat_port;
1193                   ip1->src_address.as_u32 = s1->ext_host_nat_addr.as_u32;
1194                 }
1195               udp1->checksum = 0;
1196               udp_packets++;
1197             }
1198
1199           /* Accounting */
1200           nat44_session_update_counters (s1, now,
1201                                          vlib_buffer_length_in_chain (vm, b1),
1202                                          thread_index);
1203           /* Per-user LRU list maintenance */
1204           nat44_session_update_lru (sm, s1, thread_index);
1205
1206         trace01:
1207           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1208                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1209             {
1210               nat44_ed_out2in_trace_t *t =
1211                 vlib_add_trace (vm, node, b1, sizeof (*t));
1212               t->is_slow_path = is_slow_path;
1213               t->sw_if_index = sw_if_index1;
1214               t->next_index = next1;
1215               t->session_index = ~0;
1216               if (s1)
1217                 t->session_index = s1 - tsm->sessions;
1218             }
1219
1220           pkts_processed += next1 == NAT44_ED_OUT2IN_NEXT_LOOKUP;
1221
1222           /* verify speculative enqueues, maybe switch current next frame */
1223           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
1224                                            to_next, n_left_to_next,
1225                                            bi0, bi1, next0, next1);
1226         }
1227
1228       while (n_left_from > 0 && n_left_to_next > 0)
1229         {
1230           u32 bi0;
1231           vlib_buffer_t *b0;
1232           u32 next0, sw_if_index0, rx_fib_index0, proto0, old_addr0,
1233             new_addr0;
1234           u16 old_port0, new_port0;
1235           ip4_header_t *ip0;
1236           udp_header_t *udp0;
1237           tcp_header_t *tcp0;
1238           icmp46_header_t *icmp0;
1239           snat_session_t *s0 = 0;
1240           clib_bihash_kv_16_8_t kv0, value0;
1241           ip_csum_t sum0;
1242           snat_session_key_t e_key0, l_key0;
1243           lb_nat_type_t lb_nat0;
1244           twice_nat_type_t twice_nat0;
1245           u8 identity_nat0;
1246
1247           /* speculatively enqueue b0 to the current next frame */
1248           bi0 = from[0];
1249           to_next[0] = bi0;
1250           from += 1;
1251           to_next += 1;
1252           n_left_from -= 1;
1253           n_left_to_next -= 1;
1254
1255           b0 = vlib_get_buffer (vm, bi0);
1256           next0 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
1257           vnet_buffer (b0)->snat.flags = 0;
1258           ip0 = vlib_buffer_get_current (b0);
1259
1260           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1261           rx_fib_index0 =
1262             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
1263                                                  sw_if_index0);
1264
1265           if (PREDICT_FALSE (ip0->ttl == 1))
1266             {
1267               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1268               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1269                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1270                                            0);
1271               next0 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
1272               goto trace0;
1273             }
1274
1275           udp0 = ip4_next_header (ip0);
1276           tcp0 = (tcp_header_t *) udp0;
1277           icmp0 = (icmp46_header_t *) udp0;
1278           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1279
1280           if (is_slow_path)
1281             {
1282               if (PREDICT_FALSE (proto0 == ~0))
1283                 {
1284                   s0 =
1285                     nat44_ed_out2in_unknown_proto (sm, b0, ip0, rx_fib_index0,
1286                                                    thread_index, now, vm,
1287                                                    node);
1288                   other_packets++;
1289                   if (!sm->forwarding_enabled)
1290                     {
1291                       if (!s0)
1292                         next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1293                       goto trace0;
1294                     }
1295                 }
1296
1297               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1298                 {
1299                   next0 = icmp_out2in_ed_slow_path
1300                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1301                      next0, now, thread_index, &s0);
1302                   icmp_packets++;
1303                   goto trace0;
1304                 }
1305             }
1306           else
1307             {
1308               if (PREDICT_FALSE (proto0 == ~0))
1309                 {
1310                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1311                   goto trace0;
1312                 }
1313
1314               if (ip4_is_fragment (ip0))
1315                 {
1316                   next0 = NAT44_ED_OUT2IN_NEXT_REASS;
1317                   fragments++;
1318                   goto trace0;
1319                 }
1320
1321               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1322                 {
1323                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1324                   goto trace0;
1325                 }
1326             }
1327
1328           make_ed_kv (&kv0, &ip0->dst_address, &ip0->src_address,
1329                       ip0->protocol, rx_fib_index0, udp0->dst_port,
1330                       udp0->src_port);
1331
1332           if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv0, &value0))
1333             {
1334               if (is_slow_path)
1335                 {
1336                   /* Try to match static mapping by external address and port,
1337                      destination address and port in packet */
1338                   e_key0.addr = ip0->dst_address;
1339                   e_key0.port = udp0->dst_port;
1340                   e_key0.protocol = proto0;
1341                   e_key0.fib_index = rx_fib_index0;
1342                   if (snat_static_mapping_match (sm, e_key0, &l_key0, 1, 0,
1343                                                  &twice_nat0, &lb_nat0,
1344                                                  &ip0->src_address,
1345                                                  &identity_nat0))
1346                     {
1347                       /*
1348                        * Send DHCP packets to the ipv4 stack, or we won't
1349                        * be able to use dhcp client on the outside interface
1350                        */
1351                       if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
1352                                          && (udp0->dst_port ==
1353                                              clib_host_to_net_u16
1354                                              (UDP_DST_PORT_dhcp_to_client))))
1355                         {
1356                           vnet_feature_next (&next0, b0);
1357                           goto trace0;
1358                         }
1359
1360                       if (!sm->forwarding_enabled)
1361                         {
1362                           b0->error =
1363                             node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
1364                           next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1365                         }
1366                       else
1367                         {
1368                           if (next_src_nat (sm, ip0, ip0->protocol,
1369                                             udp0->src_port, udp0->dst_port,
1370                                             thread_index, rx_fib_index0))
1371                             {
1372                               next0 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
1373                               goto trace0;
1374                             }
1375                           if (sm->num_workers > 1)
1376                             create_bypass_for_fwd_worker (sm, ip0,
1377                                                           rx_fib_index0);
1378                           else
1379                             create_bypass_for_fwd (sm, ip0, rx_fib_index0,
1380                                                    thread_index);
1381                         }
1382                       goto trace0;
1383                     }
1384
1385                   if (PREDICT_FALSE (identity_nat0))
1386                     goto trace0;
1387
1388                   if ((proto0 == SNAT_PROTOCOL_TCP) && !tcp_is_init (tcp0))
1389                     {
1390                       b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
1391                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1392                       goto trace0;
1393                     }
1394
1395                   /* Create session initiated by host from external network */
1396                   s0 = create_session_for_static_mapping_ed (sm, b0, l_key0,
1397                                                              e_key0, node,
1398                                                              thread_index,
1399                                                              twice_nat0,
1400                                                              lb_nat0, now);
1401
1402                   if (!s0)
1403                     {
1404                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1405                       goto trace0;
1406                     }
1407                 }
1408               else
1409                 {
1410                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1411                   goto trace0;
1412                 }
1413             }
1414           else
1415             {
1416               s0 = pool_elt_at_index (tsm->sessions, value0.value);
1417             }
1418
1419           old_addr0 = ip0->dst_address.as_u32;
1420           new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
1421           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1422
1423           sum0 = ip0->checksum;
1424           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
1425                                  dst_address);
1426           if (PREDICT_FALSE (is_twice_nat_session (s0)))
1427             sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
1428                                    s0->ext_host_nat_addr.as_u32, ip4_header_t,
1429                                    src_address);
1430           ip0->checksum = ip_csum_fold (sum0);
1431
1432           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1433             {
1434               old_port0 = tcp0->dst_port;
1435               new_port0 = tcp0->dst_port = s0->in2out.port;
1436
1437               sum0 = tcp0->checksum;
1438               sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
1439                                      dst_address);
1440               sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
1441                                      length);
1442               if (is_twice_nat_session (s0))
1443                 {
1444                   sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
1445                                          s0->ext_host_nat_addr.as_u32,
1446                                          ip4_header_t, dst_address);
1447                   sum0 = ip_csum_update (sum0, tcp0->src_port,
1448                                          s0->ext_host_nat_port, ip4_header_t,
1449                                          length);
1450                   tcp0->src_port = s0->ext_host_nat_port;
1451                   ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
1452                 }
1453               tcp0->checksum = ip_csum_fold (sum0);
1454               tcp_packets++;
1455               if (nat44_set_tcp_session_state_o2i
1456                   (sm, s0, tcp0, thread_index))
1457                 goto trace0;
1458             }
1459           else
1460             {
1461               udp0->dst_port = s0->in2out.port;
1462               if (is_twice_nat_session (s0))
1463                 {
1464                   udp0->src_port = s0->ext_host_nat_port;
1465                   ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
1466                 }
1467               udp0->checksum = 0;
1468               udp_packets++;
1469             }
1470
1471           /* Accounting */
1472           nat44_session_update_counters (s0, now,
1473                                          vlib_buffer_length_in_chain (vm, b0),
1474                                          thread_index);
1475           /* Per-user LRU list maintenance */
1476           nat44_session_update_lru (sm, s0, thread_index);
1477
1478         trace0:
1479           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1480                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1481             {
1482               nat44_ed_out2in_trace_t *t =
1483                 vlib_add_trace (vm, node, b0, sizeof (*t));
1484               t->is_slow_path = is_slow_path;
1485               t->sw_if_index = sw_if_index0;
1486               t->next_index = next0;
1487               t->session_index = ~0;
1488               if (s0)
1489                 t->session_index = s0 - tsm->sessions;
1490             }
1491
1492           pkts_processed += next0 == NAT44_ED_OUT2IN_NEXT_LOOKUP;
1493           /* verify speculative enqueue, maybe switch current next frame */
1494           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1495                                            to_next, n_left_to_next,
1496                                            bi0, next0);
1497         }
1498
1499       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1500     }
1501
1502   vlib_node_increment_counter (vm, stats_node_index,
1503                                NAT_OUT2IN_ED_ERROR_OUT2IN_PACKETS,
1504                                pkts_processed);
1505   vlib_node_increment_counter (vm, stats_node_index,
1506                                NAT_OUT2IN_ED_ERROR_TCP_PACKETS, tcp_packets);
1507   vlib_node_increment_counter (vm, stats_node_index,
1508                                NAT_OUT2IN_ED_ERROR_UDP_PACKETS, udp_packets);
1509   vlib_node_increment_counter (vm, stats_node_index,
1510                                NAT_OUT2IN_ED_ERROR_ICMP_PACKETS,
1511                                icmp_packets);
1512   vlib_node_increment_counter (vm, stats_node_index,
1513                                NAT_OUT2IN_ED_ERROR_OTHER_PACKETS,
1514                                other_packets);
1515   vlib_node_increment_counter (vm, stats_node_index,
1516                                NAT_OUT2IN_ED_ERROR_FRAGMENTS, fragments);
1517   return frame->n_vectors;
1518 }
1519
1520 VLIB_NODE_FN (nat44_ed_out2in_node) (vlib_main_t * vm,
1521                                      vlib_node_runtime_t * node,
1522                                      vlib_frame_t * frame)
1523 {
1524   return nat44_ed_out2in_node_fn_inline (vm, node, frame, 0);
1525 }
1526
1527 /* *INDENT-OFF* */
1528 VLIB_REGISTER_NODE (nat44_ed_out2in_node) = {
1529   .name = "nat44-ed-out2in",
1530   .vector_size = sizeof (u32),
1531   .format_trace = format_nat44_ed_out2in_trace,
1532   .type = VLIB_NODE_TYPE_INTERNAL,
1533   .n_errors = ARRAY_LEN(nat_out2in_ed_error_strings),
1534   .error_strings = nat_out2in_ed_error_strings,
1535   .runtime_data_bytes = sizeof (snat_runtime_t),
1536   .n_next_nodes = NAT44_ED_OUT2IN_N_NEXT,
1537   .next_nodes = {
1538     [NAT44_ED_OUT2IN_NEXT_DROP] = "error-drop",
1539     [NAT44_ED_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1540     [NAT44_ED_OUT2IN_NEXT_SLOW_PATH] = "nat44-ed-out2in-slowpath",
1541     [NAT44_ED_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1542     [NAT44_ED_OUT2IN_NEXT_IN2OUT] = "nat44-ed-in2out",
1543     [NAT44_ED_OUT2IN_NEXT_REASS] = "nat44-ed-out2in-reass",
1544   },
1545 };
1546 /* *INDENT-ON* */
1547
1548 VLIB_NODE_FN (nat44_ed_out2in_slowpath_node) (vlib_main_t * vm,
1549                                               vlib_node_runtime_t * node,
1550                                               vlib_frame_t * frame)
1551 {
1552   return nat44_ed_out2in_node_fn_inline (vm, node, frame, 1);
1553 }
1554
1555 /* *INDENT-OFF* */
1556 VLIB_REGISTER_NODE (nat44_ed_out2in_slowpath_node) = {
1557   .name = "nat44-ed-out2in-slowpath",
1558   .vector_size = sizeof (u32),
1559   .format_trace = format_nat44_ed_out2in_trace,
1560   .type = VLIB_NODE_TYPE_INTERNAL,
1561   .n_errors = ARRAY_LEN(nat_out2in_ed_error_strings),
1562   .error_strings = nat_out2in_ed_error_strings,
1563   .runtime_data_bytes = sizeof (snat_runtime_t),
1564   .n_next_nodes = NAT44_ED_OUT2IN_N_NEXT,
1565   .next_nodes = {
1566     [NAT44_ED_OUT2IN_NEXT_DROP] = "error-drop",
1567     [NAT44_ED_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1568     [NAT44_ED_OUT2IN_NEXT_SLOW_PATH] = "nat44-ed-out2in-slowpath",
1569     [NAT44_ED_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1570     [NAT44_ED_OUT2IN_NEXT_IN2OUT] = "nat44-ed-in2out",
1571     [NAT44_ED_OUT2IN_NEXT_REASS] = "nat44-ed-out2in-reass",
1572   },
1573 };
1574 /* *INDENT-ON* */
1575
1576 VLIB_NODE_FN (nat44_ed_out2in_reass_node) (vlib_main_t * vm,
1577                                            vlib_node_runtime_t * node,
1578                                            vlib_frame_t * frame)
1579 {
1580   u32 n_left_from, *from, *to_next;
1581   nat44_ed_out2in_next_t next_index;
1582   u32 pkts_processed = 0;
1583   snat_main_t *sm = &snat_main;
1584   f64 now = vlib_time_now (vm);
1585   u32 thread_index = vm->thread_index;
1586   snat_main_per_thread_data_t *per_thread_data =
1587     &sm->per_thread_data[thread_index];
1588   u32 *fragments_to_drop = 0;
1589   u32 *fragments_to_loopback = 0;
1590
1591   from = vlib_frame_vector_args (frame);
1592   n_left_from = frame->n_vectors;
1593   next_index = node->cached_next_index;
1594
1595   while (n_left_from > 0)
1596     {
1597       u32 n_left_to_next;
1598
1599       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1600
1601       while (n_left_from > 0 && n_left_to_next > 0)
1602         {
1603           u32 bi0, sw_if_index0, proto0, rx_fib_index0, new_addr0, old_addr0;
1604           vlib_buffer_t *b0;
1605           u32 next0;
1606           u8 cached0 = 0;
1607           ip4_header_t *ip0;
1608           nat_reass_ip4_t *reass0;
1609           udp_header_t *udp0;
1610           tcp_header_t *tcp0;
1611           icmp46_header_t *icmp0;
1612           clib_bihash_kv_16_8_t kv0, value0;
1613           snat_session_t *s0 = 0;
1614           u16 old_port0, new_port0;
1615           ip_csum_t sum0;
1616           snat_session_key_t e_key0, l_key0;
1617           lb_nat_type_t lb0;
1618           twice_nat_type_t twice_nat0;
1619           u8 identity_nat0;
1620
1621           /* speculatively enqueue b0 to the current next frame */
1622           bi0 = from[0];
1623           to_next[0] = bi0;
1624           from += 1;
1625           to_next += 1;
1626           n_left_from -= 1;
1627           n_left_to_next -= 1;
1628
1629           b0 = vlib_get_buffer (vm, bi0);
1630           next0 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
1631
1632           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1633           rx_fib_index0 =
1634             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
1635                                                  sw_if_index0);
1636
1637           if (PREDICT_FALSE (nat_reass_is_drop_frag (0)))
1638             {
1639               next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1640               b0->error = node->errors[NAT_OUT2IN_ED_ERROR_DROP_FRAGMENT];
1641               goto trace0;
1642             }
1643
1644           ip0 = (ip4_header_t *) vlib_buffer_get_current (b0);
1645           udp0 = ip4_next_header (ip0);
1646           tcp0 = (tcp_header_t *) udp0;
1647           icmp0 = (icmp46_header_t *) udp0;
1648           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1649
1650           reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
1651                                                  ip0->dst_address,
1652                                                  ip0->fragment_id,
1653                                                  ip0->protocol,
1654                                                  1, &fragments_to_drop);
1655
1656           if (PREDICT_FALSE (!reass0))
1657             {
1658               next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1659               b0->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_REASS];
1660               nat_elog_notice ("maximum reassemblies exceeded");
1661               goto trace0;
1662             }
1663
1664           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
1665             {
1666               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1667                 {
1668                   next0 = icmp_out2in_ed_slow_path
1669                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1670                      next0, now, thread_index, &s0);
1671
1672                   if (PREDICT_TRUE (next0 != NAT44_ED_OUT2IN_NEXT_DROP))
1673                     {
1674                       if (s0)
1675                         reass0->sess_index = s0 - per_thread_data->sessions;
1676                       else
1677                         reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
1678                       reass0->thread_index = thread_index;
1679                       nat_ip4_reass_get_frags (reass0,
1680                                                &fragments_to_loopback);
1681                     }
1682
1683                   goto trace0;
1684                 }
1685
1686               make_ed_kv (&kv0, &ip0->dst_address, &ip0->src_address,
1687                           ip0->protocol, rx_fib_index0, udp0->dst_port,
1688                           udp0->src_port);
1689
1690               if (clib_bihash_search_16_8
1691                   (&per_thread_data->out2in_ed, &kv0, &value0))
1692                 {
1693                   /* Try to match static mapping by external address and port,
1694                      destination address and port in packet */
1695                   e_key0.addr = ip0->dst_address;
1696                   e_key0.port = udp0->dst_port;
1697                   e_key0.protocol = proto0;
1698                   e_key0.fib_index = rx_fib_index0;
1699                   if (snat_static_mapping_match (sm, e_key0, &l_key0, 1, 0,
1700                                                  &twice_nat0, &lb0, 0,
1701                                                  &identity_nat0))
1702                     {
1703                       /*
1704                        * Send DHCP packets to the ipv4 stack, or we won't
1705                        * be able to use dhcp client on the outside interface
1706                        */
1707                       if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
1708                                          && (udp0->dst_port
1709                                              ==
1710                                              clib_host_to_net_u16
1711                                              (UDP_DST_PORT_dhcp_to_client))))
1712                         {
1713                           vnet_feature_next (&next0, b0);
1714                           goto trace0;
1715                         }
1716
1717                       if (!sm->forwarding_enabled)
1718                         {
1719                           b0->error =
1720                             node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
1721                           next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1722                         }
1723                       else
1724                         {
1725                           if (next_src_nat (sm, ip0, ip0->protocol,
1726                                             udp0->src_port, udp0->dst_port,
1727                                             thread_index, rx_fib_index0))
1728                             {
1729                               next0 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
1730                               goto trace0;
1731                             }
1732                           if (sm->num_workers > 1)
1733                             create_bypass_for_fwd_worker (sm, ip0,
1734                                                           rx_fib_index0);
1735                           else
1736                             create_bypass_for_fwd (sm, ip0, rx_fib_index0,
1737                                                    thread_index);
1738                           reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
1739                           nat_ip4_reass_get_frags (reass0,
1740                                                    &fragments_to_loopback);
1741                         }
1742                       goto trace0;
1743                     }
1744
1745                   if (PREDICT_FALSE (identity_nat0))
1746                     {
1747                       reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
1748                       goto trace0;
1749                     }
1750
1751                   if ((proto0 == SNAT_PROTOCOL_TCP) && !tcp_is_init (tcp0))
1752                     {
1753                       b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
1754                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1755                       goto trace0;
1756                     }
1757
1758                   /* Create session initiated by host from external network */
1759                   s0 = create_session_for_static_mapping_ed (sm, b0, l_key0,
1760                                                              e_key0, node,
1761                                                              thread_index,
1762                                                              twice_nat0, lb0,
1763                                                              now);
1764                   if (!s0)
1765                     {
1766                       b0->error =
1767                         node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
1768                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1769                       goto trace0;
1770                     }
1771                   reass0->sess_index = s0 - per_thread_data->sessions;
1772                   reass0->thread_index = thread_index;
1773                 }
1774               else
1775                 {
1776                   s0 = pool_elt_at_index (per_thread_data->sessions,
1777                                           value0.value);
1778                   reass0->sess_index = value0.value;
1779                 }
1780               nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
1781             }
1782           else
1783             {
1784               if (reass0->flags & NAT_REASS_FLAG_ED_DONT_TRANSLATE)
1785                 goto trace0;
1786               if (PREDICT_FALSE (reass0->sess_index == (u32) ~ 0))
1787                 {
1788                   if (nat_ip4_reass_add_fragment
1789                       (thread_index, reass0, bi0, &fragments_to_drop))
1790                     {
1791                       b0->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_FRAG];
1792                       nat_elog_notice
1793                         ("maximum fragments per reassembly exceeded");
1794                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1795                       goto trace0;
1796                     }
1797                   cached0 = 1;
1798                   goto trace0;
1799                 }
1800               s0 = pool_elt_at_index (per_thread_data->sessions,
1801                                       reass0->sess_index);
1802             }
1803
1804           old_addr0 = ip0->dst_address.as_u32;
1805           ip0->dst_address = s0->in2out.addr;
1806           new_addr0 = ip0->dst_address.as_u32;
1807           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1808
1809           sum0 = ip0->checksum;
1810           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1811                                  ip4_header_t,
1812                                  dst_address /* changed member */ );
1813           if (PREDICT_FALSE (is_twice_nat_session (s0)))
1814             sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
1815                                    s0->ext_host_nat_addr.as_u32, ip4_header_t,
1816                                    src_address);
1817           ip0->checksum = ip_csum_fold (sum0);
1818
1819           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
1820             {
1821               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1822                 {
1823                   old_port0 = tcp0->dst_port;
1824                   tcp0->dst_port = s0->in2out.port;
1825                   new_port0 = tcp0->dst_port;
1826
1827                   sum0 = tcp0->checksum;
1828                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1829                                          ip4_header_t,
1830                                          dst_address /* changed member */ );
1831
1832                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1833                                          ip4_header_t /* cheat */ ,
1834                                          length /* changed member */ );
1835                   if (is_twice_nat_session (s0))
1836                     {
1837                       sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
1838                                              s0->ext_host_nat_addr.as_u32,
1839                                              ip4_header_t, dst_address);
1840                       sum0 = ip_csum_update (sum0, tcp0->src_port,
1841                                              s0->ext_host_nat_port,
1842                                              ip4_header_t, length);
1843                       tcp0->src_port = s0->ext_host_nat_port;
1844                       ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
1845                     }
1846                   tcp0->checksum = ip_csum_fold (sum0);
1847                 }
1848               else
1849                 {
1850                   old_port0 = udp0->dst_port;
1851                   udp0->dst_port = s0->in2out.port;
1852                   if (is_twice_nat_session (s0))
1853                     {
1854                       udp0->src_port = s0->ext_host_nat_port;
1855                       ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
1856                     }
1857                   udp0->checksum = 0;
1858                 }
1859             }
1860
1861           /* Accounting */
1862           nat44_session_update_counters (s0, now,
1863                                          vlib_buffer_length_in_chain (vm, b0),
1864                                          thread_index);
1865           /* Per-user LRU list maintenance */
1866           nat44_session_update_lru (sm, s0, thread_index);
1867
1868         trace0:
1869           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1870                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1871             {
1872               nat44_reass_trace_t *t =
1873                 vlib_add_trace (vm, node, b0, sizeof (*t));
1874               t->cached = cached0;
1875               t->sw_if_index = sw_if_index0;
1876               t->next_index = next0;
1877             }
1878
1879           if (cached0)
1880             {
1881               n_left_to_next++;
1882               to_next--;
1883             }
1884           else
1885             {
1886               pkts_processed += next0 != NAT44_ED_OUT2IN_NEXT_DROP;
1887
1888               /* verify speculative enqueue, maybe switch current next frame */
1889               vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1890                                                to_next, n_left_to_next,
1891                                                bi0, next0);
1892             }
1893
1894           if (n_left_from == 0 && vec_len (fragments_to_loopback))
1895             {
1896               from = vlib_frame_vector_args (frame);
1897               u32 len = vec_len (fragments_to_loopback);
1898               if (len <= VLIB_FRAME_SIZE)
1899                 {
1900                   clib_memcpy_fast (from, fragments_to_loopback,
1901                                     sizeof (u32) * len);
1902                   n_left_from = len;
1903                   vec_reset_length (fragments_to_loopback);
1904                 }
1905               else
1906                 {
1907                   clib_memcpy_fast (from, fragments_to_loopback +
1908                                     (len - VLIB_FRAME_SIZE),
1909                                     sizeof (u32) * VLIB_FRAME_SIZE);
1910                   n_left_from = VLIB_FRAME_SIZE;
1911                   _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
1912                 }
1913             }
1914         }
1915
1916       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1917     }
1918
1919   vlib_node_increment_counter (vm, sm->ed_out2in_reass_node_index,
1920                                NAT_OUT2IN_ED_ERROR_OUT2IN_PACKETS,
1921                                pkts_processed);
1922
1923   nat_send_all_to_node (vm, fragments_to_drop, node,
1924                         &node->errors[NAT_OUT2IN_ED_ERROR_DROP_FRAGMENT],
1925                         NAT44_ED_OUT2IN_NEXT_DROP);
1926
1927   vec_free (fragments_to_drop);
1928   vec_free (fragments_to_loopback);
1929   return frame->n_vectors;
1930 }
1931
1932 /* *INDENT-OFF* */
1933 VLIB_REGISTER_NODE (nat44_ed_out2in_reass_node) = {
1934   .name = "nat44-ed-out2in-reass",
1935   .vector_size = sizeof (u32),
1936   .format_trace = format_nat44_reass_trace,
1937   .type = VLIB_NODE_TYPE_INTERNAL,
1938   .n_errors = ARRAY_LEN(nat_out2in_ed_error_strings),
1939   .error_strings = nat_out2in_ed_error_strings,
1940   .n_next_nodes = NAT44_ED_OUT2IN_N_NEXT,
1941   .next_nodes = {
1942     [NAT44_ED_OUT2IN_NEXT_DROP] = "error-drop",
1943     [NAT44_ED_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1944     [NAT44_ED_OUT2IN_NEXT_SLOW_PATH] = "nat44-ed-out2in-slowpath",
1945     [NAT44_ED_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1946     [NAT44_ED_OUT2IN_NEXT_IN2OUT] = "nat44-ed-in2out",
1947     [NAT44_ED_OUT2IN_NEXT_REASS] = "nat44-ed-out2in-reass",
1948   },
1949 };
1950 /* *INDENT-ON* */
1951
1952 /*
1953  * fd.io coding-style-patch-verification: ON
1954  *
1955  * Local Variables:
1956  * eval: (c-set-style "gnu")
1957  * End:
1958  */