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
  34 #define foreach_nat_out2in_ed_error                     \
  35 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
  36 _(OUT2IN_PACKETS, "Good out2in packets processed")      \
  37 _(OUT_OF_PORTS, "Out of ports")                         \
  38 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  39 _(NO_TRANSLATION, "No translation")                     \
  40 _(MAX_SESSIONS_EXCEEDED, "Maximum sessions exceeded")   \
  41 _(DROP_FRAGMENT, "Drop fragment")                       \
  42 _(MAX_REASS, "Maximum reassemblies exceeded")           \
  43 _(MAX_FRAG, "Maximum fragments per reassembly exceeded")\
  44 _(NON_SYN, "non-SYN packet try to create session")
  45
  46 typedef enum
  47 {
  48 #define _(sym,str) NAT_OUT2IN_ED_ERROR_##sym,
  49   foreach_nat_out2in_ed_error
  50 #undef _
  51     NAT_OUT2IN_ED_N_ERROR,
  52 } nat_out2in_ed_error_t;
  53
  54 static char *nat_out2in_ed_error_strings[] = {
  55 #define _(sym,string) string,
  56   foreach_nat_out2in_ed_error
  57 #undef _
  58 };
  59
  60 typedef enum
  61 {
  62   NAT44_ED_OUT2IN_NEXT_DROP,
  63   NAT44_ED_OUT2IN_NEXT_LOOKUP,
  64   NAT44_ED_OUT2IN_NEXT_ICMP_ERROR,
  65   NAT44_ED_OUT2IN_NEXT_IN2OUT,
  66   NAT44_ED_OUT2IN_NEXT_SLOW_PATH,
  67   NAT44_ED_OUT2IN_NEXT_REASS,
  68   NAT44_ED_OUT2IN_N_NEXT,
  69 } nat44_ed_out2in_next_t;
  70
  71 typedef struct
  72 {
  73   u32 sw_if_index;
  74   u32 next_index;
  75   u32 session_index;
  76   u32 is_slow_path;
  77 } nat44_ed_out2in_trace_t;
  78
  79 vlib_node_registration_t nat44_ed_out2in_node;
  80 vlib_node_registration_t nat44_ed_out2in_slowpath_node;
  81 vlib_node_registration_t nat44_ed_out2in_reass_node;
  82
  83 static u8 *
  84 format_nat44_ed_out2in_trace (u8 * s, va_list * args)
  85 {
  86   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  87   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  88   nat44_ed_out2in_trace_t *t = va_arg (*args, nat44_ed_out2in_trace_t *);
  89   char *tag;
  90
  91   tag =
  92     t->is_slow_path ? "NAT44_OUT2IN_ED_SLOW_PATH" :
  93     "NAT44_OUT2IN_ED_FAST_PATH";
  94
  95   s = format (s, "%s: sw_if_index %d, next index %d, session %d", tag,
  96               t->sw_if_index, t->next_index, t->session_index);
  97
  98   return s;
  99 }
 100
 101 static inline u32
 102 icmp_out2in_ed_slow_path (snat_main_t * sm, vlib_buffer_t * b0,
 103                           ip4_header_t * ip0, icmp46_header_t * icmp0,
 104                           u32 sw_if_index0, u32 rx_fib_index0,
 105                           vlib_node_runtime_t * node, u32 next0, f64 now,
 106                           u32 thread_index, snat_session_t ** p_s0)
 107 {
 108   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 109                        next0, thread_index, p_s0, 0);
 110   snat_session_t *s0 = *p_s0;
 111   if (PREDICT_TRUE (next0 != NAT44_ED_OUT2IN_NEXT_DROP && s0))
 112     {
 113       /* Accounting */
 114       nat44_session_update_counters (s0, now,
 115                                      vlib_buffer_length_in_chain
 116                                      (sm->vlib_main, b0));
 117       /* Per-user LRU list maintenance */
 118       nat44_session_update_lru (sm, s0, thread_index);
 119     }
 120   return next0;
 121 }
 122
 123 int
 124 nat44_o2i_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg)
 125 {
 126   snat_main_t *sm = &snat_main;
 127   nat44_is_idle_session_ctx_t *ctx = arg;
 128   snat_session_t *s;
 129   u64 sess_timeout_time;
 130   nat_ed_ses_key_t ed_key;
 131   clib_bihash_kv_16_8_t ed_kv;
 132   int i;
 133   snat_address_t *a;
 134   snat_session_key_t key;
 135   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
 136                                                        ctx->thread_index);
 137
 138   s = pool_elt_at_index (tsm->sessions, kv->value);
 139   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
 140   if (ctx->now >= sess_timeout_time)
 141     {
 142       ed_key.l_addr = s->in2out.addr;
 143       ed_key.r_addr = s->ext_host_addr;
 144       ed_key.fib_index = s->in2out.fib_index;
 145       if (snat_is_unk_proto_session (s))
 146         {
 147           ed_key.proto = s->in2out.port;
 148           ed_key.r_port = 0;
 149           ed_key.l_port = 0;
 150         }
 151       else
 152         {
 153           ed_key.proto = snat_proto_to_ip_proto (s->in2out.protocol);
 154           ed_key.l_port = s->in2out.port;
 155           ed_key.r_port = s->ext_host_port;
 156         }
 157       if (is_twice_nat_session (s))
 158         {
 159           ed_key.r_addr = s->ext_host_nat_addr;
 160           ed_key.r_port = s->ext_host_nat_port;
 161         }
 162       ed_kv.key[0] = ed_key.as_u64[0];
 163       ed_kv.key[1] = ed_key.as_u64[1];
 164       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &ed_kv, 0))
 165         nat_log_warn ("in2out_ed key del failed");
 166
 167       if (snat_is_unk_proto_session (s))
 168         goto delete;
 169
 170       snat_ipfix_logging_nat44_ses_delete (s->in2out.addr.as_u32,
 171                                            s->out2in.addr.as_u32,
 172                                            s->in2out.protocol,
 173                                            s->in2out.port,
 174                                            s->out2in.port,
 175                                            s->in2out.fib_index);
 176
 177       nat_syslog_nat44_sdel (s->user_index, s->in2out.fib_index,
 178                              &s->in2out.addr, s->in2out.port,
 179                              &s->ext_host_nat_addr, s->ext_host_nat_port,
 180                              &s->out2in.addr, s->out2in.port,
 181                              &s->ext_host_addr, s->ext_host_port,
 182                              s->in2out.protocol, is_twice_nat_session (s));
 183
 184       if (is_twice_nat_session (s))
 185         {
 186           for (i = 0; i < vec_len (sm->twice_nat_addresses); i++)
 187             {
 188               key.protocol = s->in2out.protocol;
 189               key.port = s->ext_host_nat_port;
 190               a = sm->twice_nat_addresses + i;
 191               if (a->addr.as_u32 == s->ext_host_nat_addr.as_u32)
 192                 {
 193                   snat_free_outside_address_and_port (sm->twice_nat_addresses,
 194                                                       ctx->thread_index,
 195                                                       &key);
 196                   break;
 197                 }
 198             }
 199         }
 200
 201       if (snat_is_session_static (s))
 202         goto delete;
 203
 204       snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
 205                                           &s->out2in);
 206     delete:
 207       nat44_delete_session (sm, s, ctx->thread_index);
 208       return 1;
 209     }
 210
 211   return 0;
 212 }
 213
 214 static snat_session_t *
 215 create_session_for_static_mapping_ed (snat_main_t * sm,
 216                                       vlib_buffer_t * b,
 217                                       snat_session_key_t l_key,
 218                                       snat_session_key_t e_key,
 219                                       vlib_node_runtime_t * node,
 220                                       u32 thread_index,
 221                                       twice_nat_type_t twice_nat,
 222                                       lb_nat_type_t lb_nat, f64 now)
 223 {
 224   snat_session_t *s;
 225   snat_user_t *u;
 226   ip4_header_t *ip;
 227   udp_header_t *udp;
 228   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 229   clib_bihash_kv_16_8_t kv;
 230   snat_session_key_t eh_key;
 231   nat44_is_idle_session_ctx_t ctx;
 232
 233   if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 234     {
 235       b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
 236       nat_log_notice ("maximum sessions exceeded");
 237       return 0;
 238     }
 239
 240   u = nat_user_get_or_create (sm, &l_key.addr, l_key.fib_index, thread_index);
 241   if (!u)
 242     {
 243       nat_log_warn ("create NAT user failed");
 244       return 0;
 245     }
 246
 247   s = nat_ed_session_alloc (sm, u, thread_index, now);
 248   if (!s)
 249     {
 250       nat44_delete_user_with_no_session (sm, u, thread_index);
 251       nat_log_warn ("create NAT session failed");
 252       return 0;
 253     }
 254
 255   ip = vlib_buffer_get_current (b);
 256   udp = ip4_next_header (ip);
 257
 258   s->ext_host_addr.as_u32 = ip->src_address.as_u32;
 259   s->ext_host_port = e_key.protocol == SNAT_PROTOCOL_ICMP ? 0 : udp->src_port;
 260   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 261   if (lb_nat)
 262     s->flags |= SNAT_SESSION_FLAG_LOAD_BALANCING;
 263   if (lb_nat == AFFINITY_LB_NAT)
 264     s->flags |= SNAT_SESSION_FLAG_AFFINITY;
 265   s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
 266   s->out2in = e_key;
 267   s->in2out = l_key;
 268   s->in2out.protocol = s->out2in.protocol;
 269   user_session_increment (sm, u, 1);
 270
 271   /* Add to lookup tables */
 272   make_ed_kv (&kv, &e_key.addr, &s->ext_host_addr, ip->protocol,
 273               e_key.fib_index, e_key.port, s->ext_host_port);
 274   kv.value = s - tsm->sessions;
 275   ctx.now = now;
 276   ctx.thread_index = thread_index;
 277   if (clib_bihash_add_or_overwrite_stale_16_8 (&tsm->out2in_ed, &kv,
 278                                                nat44_o2i_ed_is_idle_session_cb,
 279                                                &ctx))
 280     nat_log_notice ("out2in-ed key add failed");
 281
 282   if (twice_nat == TWICE_NAT || (twice_nat == TWICE_NAT_SELF &&
 283                                  ip->src_address.as_u32 == l_key.addr.as_u32))
 284     {
 285       eh_key.protocol = e_key.protocol;
 286       if (snat_alloc_outside_address_and_port (sm->twice_nat_addresses, 0,
 287                                                thread_index, &eh_key,
 288                                                sm->port_per_thread,
 289                                                tsm->snat_thread_index))
 290         {
 291           b->error = node->errors[NAT_OUT2IN_ED_ERROR_OUT_OF_PORTS];
 292           nat44_delete_session (sm, s, thread_index);
 293           if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &kv, 0))
 294             nat_log_notice ("out2in-ed key del failed");
 295           return 0;
 296         }
 297       s->ext_host_nat_addr.as_u32 = eh_key.addr.as_u32;
 298       s->ext_host_nat_port = eh_key.port;
 299       s->flags |= SNAT_SESSION_FLAG_TWICE_NAT;
 300       make_ed_kv (&kv, &l_key.addr, &s->ext_host_nat_addr, ip->protocol,
 301                   l_key.fib_index, l_key.port, s->ext_host_nat_port);
 302     }
 303   else
 304     {
 305       make_ed_kv (&kv, &l_key.addr, &s->ext_host_addr, ip->protocol,
 306                   l_key.fib_index, l_key.port, s->ext_host_port);
 307     }
 308   kv.value = s - tsm->sessions;
 309   if (clib_bihash_add_or_overwrite_stale_16_8 (&tsm->in2out_ed, &kv,
 310                                                nat44_i2o_ed_is_idle_session_cb,
 311                                                &ctx))
 312     nat_log_notice ("in2out-ed key add failed");
 313
 314   snat_ipfix_logging_nat44_ses_create (s->in2out.addr.as_u32,
 315                                        s->out2in.addr.as_u32,
 316                                        s->in2out.protocol,
 317                                        s->in2out.port,
 318                                        s->out2in.port, s->in2out.fib_index);
 319
 320   nat_syslog_nat44_sdel (s->user_index, s->in2out.fib_index,
 321                          &s->in2out.addr, s->in2out.port,
 322                          &s->ext_host_nat_addr, s->ext_host_nat_port,
 323                          &s->out2in.addr, s->out2in.port,
 324                          &s->ext_host_addr, s->ext_host_port,
 325                          s->in2out.protocol, is_twice_nat_session (s));
 326
 327   return s;
 328 }
 329
 330 static_always_inline int
 331 icmp_get_ed_key (ip4_header_t * ip0, nat_ed_ses_key_t * p_key0)
 332 {
 333   icmp46_header_t *icmp0;
 334   nat_ed_ses_key_t key0;
 335   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 336   ip4_header_t *inner_ip0;
 337   void *l4_header = 0;
 338   icmp46_header_t *inner_icmp0;
 339
 340   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 341   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 342
 343   if (!icmp_is_error_message (icmp0))
 344     {
 345       key0.proto = IP_PROTOCOL_ICMP;
 346       key0.l_addr = ip0->dst_address;
 347       key0.r_addr = ip0->src_address;
 348       key0.l_port = echo0->identifier;
 349       key0.r_port = 0;
 350     }
 351   else
 352     {
 353       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 354       l4_header = ip4_next_header (inner_ip0);
 355       key0.proto = inner_ip0->protocol;
 356       key0.l_addr = inner_ip0->src_address;
 357       key0.r_addr = inner_ip0->dst_address;
 358       switch (ip_proto_to_snat_proto (inner_ip0->protocol))
 359         {
 360         case SNAT_PROTOCOL_ICMP:
 361           inner_icmp0 = (icmp46_header_t *) l4_header;
 362           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 363           key0.l_port = inner_echo0->identifier;
 364           key0.r_port = 0;
 365           break;
 366         case SNAT_PROTOCOL_UDP:
 367         case SNAT_PROTOCOL_TCP:
 368           key0.l_port = ((tcp_udp_header_t *) l4_header)->src_port;
 369           key0.r_port = ((tcp_udp_header_t *) l4_header)->dst_port;
 370           break;
 371         default:
 372           return -1;
 373         }
 374     }
 375   *p_key0 = key0;
 376   return 0;
 377 }
 378
 379 static int
 380 next_src_nat (snat_main_t * sm, ip4_header_t * ip, u8 proto, u16 src_port,
 381               u16 dst_port, u32 thread_index, u32 rx_fib_index)
 382 {
 383   clib_bihash_kv_16_8_t kv, value;
 384   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 385
 386   make_ed_kv (&kv, &ip->src_address, &ip->dst_address, proto,
 387               rx_fib_index, src_port, dst_port);
 388   if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
 389     return 1;
 390
 391   return 0;
 392 }
 393
 394 static void
 395 create_bypass_for_fwd (snat_main_t * sm, ip4_header_t * ip, u32 rx_fib_index,
 396                        u32 thread_index)
 397 {
 398   nat_ed_ses_key_t key;
 399   clib_bihash_kv_16_8_t kv, value;
 400   udp_header_t *udp;
 401   snat_user_t *u;
 402   snat_session_t *s = 0;
 403   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 404   f64 now = vlib_time_now (sm->vlib_main);
 405
 406   if (ip->protocol == IP_PROTOCOL_ICMP)
 407     {
 408       if (icmp_get_ed_key (ip, &key))
 409         return;
 410     }
 411   else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
 412     {
 413       udp = ip4_next_header (ip);
 414       key.r_addr = ip->src_address;
 415       key.l_addr = ip->dst_address;
 416       key.proto = ip->protocol;
 417       key.l_port = udp->dst_port;
 418       key.r_port = udp->src_port;
 419     }
 420   else
 421     {
 422       key.r_addr = ip->src_address;
 423       key.l_addr = ip->dst_address;
 424       key.proto = ip->protocol;
 425       key.l_port = key.r_port = 0;
 426     }
 427   key.fib_index = 0;
 428   kv.key[0] = key.as_u64[0];
 429   kv.key[1] = key.as_u64[1];
 430
 431   if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
 432     {
 433       s = pool_elt_at_index (tsm->sessions, value.value);
 434     }
 435   else
 436     {
 437       if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 438         return;
 439
 440       u = nat_user_get_or_create (sm, &ip->dst_address, sm->inside_fib_index,
 441                                   thread_index);
 442       if (!u)
 443         {
 444           nat_log_warn ("create NAT user failed");
 445           return;
 446         }
 447
 448       s = nat_ed_session_alloc (sm, u, thread_index, now);
 449       if (!s)
 450         {
 451           nat44_delete_user_with_no_session (sm, u, thread_index);
 452           nat_log_warn ("create NAT session failed");
 453           return;
 454         }
 455
 456       s->ext_host_addr = key.r_addr;
 457       s->ext_host_port = key.r_port;
 458       s->flags |= SNAT_SESSION_FLAG_FWD_BYPASS;
 459       s->out2in.addr = key.l_addr;
 460       s->out2in.port = key.l_port;
 461       s->out2in.protocol = ip_proto_to_snat_proto (key.proto);
 462       s->out2in.fib_index = 0;
 463       s->in2out = s->out2in;
 464       user_session_increment (sm, u, 0);
 465
 466       kv.value = s - tsm->sessions;
 467       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &kv, 1))
 468         nat_log_notice ("in2out_ed key add failed");
 469     }
 470
 471   if (ip->protocol == IP_PROTOCOL_TCP)
 472     {
 473       tcp_header_t *tcp = ip4_next_header (ip);
 474       if (nat44_set_tcp_session_state_o2i (sm, s, tcp, thread_index))
 475         return;
 476     }
 477
 478   /* Accounting */
 479   nat44_session_update_counters (s, now, 0);
 480   /* Per-user LRU list maintenance */
 481   nat44_session_update_lru (sm, s, thread_index);
 482 }
 483
 484 u32
 485 icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
 486                       u32 thread_index, vlib_buffer_t * b, ip4_header_t * ip,
 487                       u8 * p_proto, snat_session_key_t * p_value,
 488                       u8 * p_dont_translate, void *d, void *e)
 489 {
 490   u32 next = ~0, sw_if_index, rx_fib_index;
 491   icmp46_header_t *icmp;
 492   nat_ed_ses_key_t key;
 493   clib_bihash_kv_16_8_t kv, value;
 494   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 495   snat_session_t *s = 0;
 496   u8 dont_translate = 0, is_addr_only, identity_nat;
 497   snat_session_key_t e_key, l_key;
 498
 499   icmp = (icmp46_header_t *) ip4_next_header (ip);
 500   sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
 501   rx_fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 502
 503   if (icmp_get_ed_key (ip, &key))
 504     {
 505       b->error = node->errors[NAT_OUT2IN_ED_ERROR_UNSUPPORTED_PROTOCOL];
 506       next = NAT44_ED_OUT2IN_NEXT_DROP;
 507       goto out;
 508     }
 509   key.fib_index = rx_fib_index;
 510   kv.key[0] = key.as_u64[0];
 511   kv.key[1] = key.as_u64[1];
 512
 513   if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv, &value))
 514     {
 515       /* Try to match static mapping */
 516       e_key.addr = ip->dst_address;
 517       e_key.port = key.l_port;
 518       e_key.protocol = ip_proto_to_snat_proto (key.proto);
 519       e_key.fib_index = rx_fib_index;
 520       if (snat_static_mapping_match
 521           (sm, e_key, &l_key, 1, &is_addr_only, 0, 0, 0, &identity_nat))
 522         {
 523           if (!sm->forwarding_enabled)
 524             {
 525               /* Don't NAT packet aimed at the intfc address */
 526               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index,
 527                                                     ip->dst_address.as_u32)))
 528                 {
 529                   dont_translate = 1;
 530                   goto out;
 531                 }
 532               b->error = node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
 533               next = NAT44_ED_OUT2IN_NEXT_DROP;
 534               goto out;
 535             }
 536           else
 537             {
 538               dont_translate = 1;
 539               if (next_src_nat (sm, ip, key.proto, key.l_port, key.r_port,
 540                                 thread_index, rx_fib_index))
 541                 {
 542                   next = NAT44_ED_OUT2IN_NEXT_IN2OUT;
 543                   goto out;
 544                 }
 545               create_bypass_for_fwd (sm, ip, rx_fib_index, thread_index);
 546               goto out;
 547             }
 548         }
 549
 550       if (PREDICT_FALSE (icmp->type != ICMP4_echo_reply &&
 551                          (icmp->type != ICMP4_echo_request || !is_addr_only)))
 552         {
 553           b->error = node->errors[NAT_OUT2IN_ED_ERROR_BAD_ICMP_TYPE];
 554           next = NAT44_ED_OUT2IN_NEXT_DROP;
 555           goto out;
 556         }
 557
 558       if (PREDICT_FALSE (identity_nat))
 559         {
 560           dont_translate = 1;
 561           goto out;
 562         }
 563
 564       /* Create session initiated by host from external network */
 565       s = create_session_for_static_mapping_ed (sm, b, l_key, e_key, node,
 566                                                 thread_index, 0, 0,
 567                                                 vlib_time_now
 568                                                 (sm->vlib_main));
 569
 570       if (!s)
 571         {
 572           next = NAT44_ED_OUT2IN_NEXT_DROP;
 573           goto out;
 574         }
 575     }
 576   else
 577     {
 578       if (PREDICT_FALSE (icmp->type != ICMP4_echo_reply &&
 579                          icmp->type != ICMP4_echo_request &&
 580                          !icmp_is_error_message (icmp)))
 581         {
 582           b->error = node->errors[NAT_OUT2IN_ED_ERROR_BAD_ICMP_TYPE];
 583           next = NAT44_ED_OUT2IN_NEXT_DROP;
 584           goto out;
 585         }
 586
 587       s = pool_elt_at_index (tsm->sessions, value.value);
 588     }
 589
 590   *p_proto = ip_proto_to_snat_proto (key.proto);
 591 out:
 592   if (s)
 593     *p_value = s->in2out;
 594   *p_dont_translate = dont_translate;
 595   if (d)
 596     *(snat_session_t **) d = s;
 597   return next;
 598 }
 599
 600 static snat_session_t *
 601 nat44_ed_out2in_unknown_proto (snat_main_t * sm,
 602                                vlib_buffer_t * b,
 603                                ip4_header_t * ip,
 604                                u32 rx_fib_index,
 605                                u32 thread_index,
 606                                f64 now,
 607                                vlib_main_t * vm, vlib_node_runtime_t * node)
 608 {
 609   clib_bihash_kv_8_8_t kv, value;
 610   clib_bihash_kv_16_8_t s_kv, s_value;
 611   snat_static_mapping_t *m;
 612   u32 old_addr, new_addr;
 613   ip_csum_t sum;
 614   snat_session_t *s;
 615   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 616   snat_user_t *u;
 617
 618   old_addr = ip->dst_address.as_u32;
 619
 620   make_ed_kv (&s_kv, &ip->dst_address, &ip->src_address, ip->protocol,
 621               rx_fib_index, 0, 0);
 622
 623   if (!clib_bihash_search_16_8 (&tsm->out2in_ed, &s_kv, &s_value))
 624     {
 625       s = pool_elt_at_index (tsm->sessions, s_value.value);
 626       new_addr = ip->dst_address.as_u32 = s->in2out.addr.as_u32;
 627     }
 628   else
 629     {
 630       if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 631         {
 632           b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
 633           nat_log_notice ("maximum sessions exceeded");
 634           return 0;
 635         }
 636
 637       make_sm_kv (&kv, &ip->dst_address, 0, 0, 0);
 638       if (clib_bihash_search_8_8
 639           (&sm->static_mapping_by_external, &kv, &value))
 640         {
 641           b->error = node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
 642           return 0;
 643         }
 644
 645       m = pool_elt_at_index (sm->static_mappings, value.value);
 646
 647       new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 648
 649       u = nat_user_get_or_create (sm, &m->local_addr, m->fib_index,
 650                                   thread_index);
 651       if (!u)
 652         {
 653           nat_log_warn ("create NAT user failed");
 654           return 0;
 655         }
 656
 657       /* Create a new session */
 658       s = nat_ed_session_alloc (sm, u, thread_index, now);
 659       if (!s)
 660         {
 661           nat44_delete_user_with_no_session (sm, u, thread_index);
 662           nat_log_warn ("create NAT session failed");
 663           return 0;
 664         }
 665
 666       s->ext_host_addr.as_u32 = ip->src_address.as_u32;
 667       s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
 668       s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 669       s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
 670       s->out2in.addr.as_u32 = old_addr;
 671       s->out2in.fib_index = rx_fib_index;
 672       s->in2out.addr.as_u32 = new_addr;
 673       s->in2out.fib_index = m->fib_index;
 674       s->in2out.port = s->out2in.port = ip->protocol;
 675       user_session_increment (sm, u, 1);
 676
 677       /* Add to lookup tables */
 678       s_kv.value = s - tsm->sessions;
 679       if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &s_kv, 1))
 680         nat_log_notice ("out2in key add failed");
 681
 682       make_ed_kv (&s_kv, &ip->dst_address, &ip->src_address, ip->protocol,
 683                   m->fib_index, 0, 0);
 684       s_kv.value = s - tsm->sessions;
 685       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &s_kv, 1))
 686         nat_log_notice ("in2out key add failed");
 687     }
 688
 689   /* Update IP checksum */
 690   sum = ip->checksum;
 691   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 692   ip->checksum = ip_csum_fold (sum);
 693
 694   vnet_buffer (b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
 695
 696   /* Accounting */
 697   nat44_session_update_counters (s, now, vlib_buffer_length_in_chain (vm, b));
 698   /* Per-user LRU list maintenance */
 699   nat44_session_update_lru (sm, s, thread_index);
 700
 701   return s;
 702 }
 703
 704 static inline uword
 705 nat44_ed_out2in_node_fn_inline (vlib_main_t * vm,
 706                                 vlib_node_runtime_t * node,
 707                                 vlib_frame_t * frame, int is_slow_path)
 708 {
 709   u32 n_left_from, *from, *to_next, pkts_processed = 0, stats_node_index;
 710   nat44_ed_out2in_next_t next_index;
 711   snat_main_t *sm = &snat_main;
 712   f64 now = vlib_time_now (vm);
 713   u32 thread_index = vm->thread_index;
 714   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 715
 716   stats_node_index = is_slow_path ? nat44_ed_out2in_slowpath_node.index :
 717     nat44_ed_out2in_node.index;
 718
 719   from = vlib_frame_vector_args (frame);
 720   n_left_from = frame->n_vectors;
 721   next_index = node->cached_next_index;
 722
 723   while (n_left_from > 0)
 724     {
 725       u32 n_left_to_next;
 726
 727       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 728
 729       while (n_left_from >= 4 && n_left_to_next >= 2)
 730         {
 731           u32 bi0, bi1;
 732           vlib_buffer_t *b0, *b1;
 733           u32 next0, sw_if_index0, rx_fib_index0, proto0, old_addr0,
 734             new_addr0;
 735           u32 next1, sw_if_index1, rx_fib_index1, proto1, old_addr1,
 736             new_addr1;
 737           u16 old_port0, new_port0, old_port1, new_port1;
 738           ip4_header_t *ip0, *ip1;
 739           udp_header_t *udp0, *udp1;
 740           tcp_header_t *tcp0, *tcp1;
 741           icmp46_header_t *icmp0, *icmp1;
 742           snat_session_t *s0 = 0, *s1 = 0;
 743           clib_bihash_kv_16_8_t kv0, value0, kv1, value1;
 744           ip_csum_t sum0, sum1;
 745           snat_session_key_t e_key0, l_key0, e_key1, l_key1;
 746           lb_nat_type_t lb_nat0, lb_nat1;
 747           twice_nat_type_t twice_nat0, twice_nat1;
 748           u8 identity_nat0, identity_nat1;
 749
 750           /* Prefetch next iteration. */
 751           {
 752             vlib_buffer_t *p2, *p3;
 753
 754             p2 = vlib_get_buffer (vm, from[2]);
 755             p3 = vlib_get_buffer (vm, from[3]);
 756
 757             vlib_prefetch_buffer_header (p2, LOAD);
 758             vlib_prefetch_buffer_header (p3, LOAD);
 759
 760             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 761             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 762           }
 763
 764           /* speculatively enqueue b0 and b1 to the current next frame */
 765           to_next[0] = bi0 = from[0];
 766           to_next[1] = bi1 = from[1];
 767           from += 2;
 768           to_next += 2;
 769           n_left_from -= 2;
 770           n_left_to_next -= 2;
 771
 772           b0 = vlib_get_buffer (vm, bi0);
 773           b1 = vlib_get_buffer (vm, bi1);
 774
 775           next0 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
 776           vnet_buffer (b0)->snat.flags = 0;
 777           ip0 = vlib_buffer_get_current (b0);
 778
 779           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 780           rx_fib_index0 =
 781             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
 782                                                  sw_if_index0);
 783
 784           if (PREDICT_FALSE (ip0->ttl == 1))
 785             {
 786               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 787               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 788                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 789                                            0);
 790               next0 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
 791               goto trace00;
 792             }
 793
 794           udp0 = ip4_next_header (ip0);
 795           tcp0 = (tcp_header_t *) udp0;
 796           icmp0 = (icmp46_header_t *) udp0;
 797           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 798
 799           if (is_slow_path)
 800             {
 801               if (PREDICT_FALSE (proto0 == ~0))
 802                 {
 803                   s0 =
 804                     nat44_ed_out2in_unknown_proto (sm, b0, ip0, rx_fib_index0,
 805                                                    thread_index, now, vm,
 806                                                    node);
 807                   if (!sm->forwarding_enabled)
 808                     {
 809                       if (!s0)
 810                         next0 = NAT44_ED_OUT2IN_NEXT_DROP;
 811                       goto trace00;
 812                     }
 813                 }
 814
 815               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 816                 {
 817                   next0 = icmp_out2in_ed_slow_path
 818                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 819                      next0, now, thread_index, &s0);
 820                   goto trace00;
 821                 }
 822             }
 823           else
 824             {
 825               if (PREDICT_FALSE (proto0 == ~0))
 826                 {
 827                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
 828                   goto trace00;
 829                 }
 830
 831               if (ip4_is_fragment (ip0))
 832                 {
 833                   next0 = NAT44_ED_OUT2IN_NEXT_REASS;
 834                   goto trace00;
 835                 }
 836
 837               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 838                 {
 839                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
 840                   goto trace00;
 841                 }
 842             }
 843
 844           make_ed_kv (&kv0, &ip0->dst_address, &ip0->src_address,
 845                       ip0->protocol, rx_fib_index0, udp0->dst_port,
 846                       udp0->src_port);
 847
 848           if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv0, &value0))
 849             {
 850               if (is_slow_path)
 851                 {
 852                   /* Try to match static mapping by external address and port,
 853                      destination address and port in packet */
 854                   e_key0.addr = ip0->dst_address;
 855                   e_key0.port = udp0->dst_port;
 856                   e_key0.protocol = proto0;
 857                   e_key0.fib_index = rx_fib_index0;
 858                   if (snat_static_mapping_match (sm, e_key0, &l_key0, 1, 0,
 859                                                  &twice_nat0, &lb_nat0,
 860                                                  &ip0->src_address,
 861                                                  &identity_nat0))
 862                     {
 863                       /*
 864                        * Send DHCP packets to the ipv4 stack, or we won't
 865                        * be able to use dhcp client on the outside interface
 866                        */
 867                       if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
 868                                          && (udp0->dst_port ==
 869                                              clib_host_to_net_u16
 870                                              (UDP_DST_PORT_dhcp_to_client))))
 871                         {
 872                           vnet_feature_next (&next0, b0);
 873                           goto trace00;
 874                         }
 875
 876                       if (!sm->forwarding_enabled)
 877                         {
 878                           b0->error =
 879                             node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
 880                           next0 = NAT44_ED_OUT2IN_NEXT_DROP;
 881                         }
 882                       else
 883                         {
 884                           if (next_src_nat (sm, ip0, ip0->protocol,
 885                                             udp0->src_port, udp0->dst_port,
 886                                             thread_index, rx_fib_index0))
 887                             {
 888                               next0 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
 889                               goto trace00;
 890                             }
 891                           create_bypass_for_fwd (sm, ip0, rx_fib_index0,
 892                                                  thread_index);
 893                         }
 894                       goto trace00;
 895                     }
 896
 897                   if (PREDICT_FALSE (identity_nat0))
 898                     goto trace00;
 899
 900                   if ((proto0 == SNAT_PROTOCOL_TCP) && !tcp_is_init (tcp0))
 901                     {
 902                       b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
 903                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
 904                       goto trace00;
 905                     }
 906
 907                   /* Create session initiated by host from external network */
 908                   s0 = create_session_for_static_mapping_ed (sm, b0, l_key0,
 909                                                              e_key0, node,
 910                                                              thread_index,
 911                                                              twice_nat0,
 912                                                              lb_nat0, now);
 913
 914                   if (!s0)
 915                     {
 916                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
 917                       goto trace00;
 918                     }
 919                 }
 920               else
 921                 {
 922                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
 923                   goto trace00;
 924                 }
 925             }
 926           else
 927             {
 928               s0 = pool_elt_at_index (tsm->sessions, value0.value);
 929             }
 930
 931           old_addr0 = ip0->dst_address.as_u32;
 932           new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
 933           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 934
 935           sum0 = ip0->checksum;
 936           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 937                                  dst_address);
 938           if (PREDICT_FALSE (is_twice_nat_session (s0)))
 939             sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
 940                                    s0->ext_host_nat_addr.as_u32, ip4_header_t,
 941                                    src_address);
 942           ip0->checksum = ip_csum_fold (sum0);
 943
 944           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 945             {
 946               old_port0 = tcp0->dst_port;
 947               new_port0 = tcp0->dst_port = s0->in2out.port;
 948
 949               sum0 = tcp0->checksum;
 950               sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 951                                      dst_address);
 952               sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
 953                                      length);
 954               if (is_twice_nat_session (s0))
 955                 {
 956                   sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
 957                                          s0->ext_host_nat_addr.as_u32,
 958                                          ip4_header_t, dst_address);
 959                   sum0 = ip_csum_update (sum0, tcp0->src_port,
 960                                          s0->ext_host_nat_port, ip4_header_t,
 961                                          length);
 962                   tcp0->src_port = s0->ext_host_nat_port;
 963                   ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
 964                 }
 965               tcp0->checksum = ip_csum_fold (sum0);
 966               if (nat44_set_tcp_session_state_o2i
 967                   (sm, s0, tcp0, thread_index))
 968                 goto trace00;
 969             }
 970           else
 971             {
 972               udp0->dst_port = s0->in2out.port;
 973               if (is_twice_nat_session (s0))
 974                 {
 975                   udp0->src_port = s0->ext_host_nat_port;
 976                   ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
 977                 }
 978               udp0->checksum = 0;
 979             }
 980
 981           /* Accounting */
 982           nat44_session_update_counters (s0, now,
 983                                          vlib_buffer_length_in_chain (vm,
 984                                                                       b0));
 985           /* Per-user LRU list maintenance */
 986           nat44_session_update_lru (sm, s0, thread_index);
 987
 988         trace00:
 989           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 990                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 991             {
 992               nat44_ed_out2in_trace_t *t =
 993                 vlib_add_trace (vm, node, b0, sizeof (*t));
 994               t->is_slow_path = is_slow_path;
 995               t->sw_if_index = sw_if_index0;
 996               t->next_index = next0;
 997               t->session_index = ~0;
 998               if (s0)
 999                 t->session_index = s0 - tsm->sessions;
1000             }
1001
1002           pkts_processed += next0 != NAT44_ED_OUT2IN_NEXT_DROP;
1003
1004           next1 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
1005           vnet_buffer (b1)->snat.flags = 0;
1006           ip1 = vlib_buffer_get_current (b1);
1007
1008           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
1009           rx_fib_index1 =
1010             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
1011                                                  sw_if_index1);
1012
1013           if (PREDICT_FALSE (ip1->ttl == 1))
1014             {
1015               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1016               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
1017                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1018                                            0);
1019               next1 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
1020               goto trace01;
1021             }
1022
1023           udp1 = ip4_next_header (ip1);
1024           tcp1 = (tcp_header_t *) udp1;
1025           icmp1 = (icmp46_header_t *) udp1;
1026           proto1 = ip_proto_to_snat_proto (ip1->protocol);
1027
1028           if (is_slow_path)
1029             {
1030               if (PREDICT_FALSE (proto1 == ~0))
1031                 {
1032                   s1 =
1033                     nat44_ed_out2in_unknown_proto (sm, b1, ip1, rx_fib_index1,
1034                                                    thread_index, now, vm,
1035                                                    node);
1036                   if (!sm->forwarding_enabled)
1037                     {
1038                       if (!s1)
1039                         next1 = NAT44_ED_OUT2IN_NEXT_DROP;
1040                       goto trace01;
1041                     }
1042                 }
1043
1044               if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
1045                 {
1046                   next1 = icmp_out2in_ed_slow_path
1047                     (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
1048                      next1, now, thread_index, &s1);
1049                   goto trace01;
1050                 }
1051             }
1052           else
1053             {
1054               if (PREDICT_FALSE (proto1 == ~0))
1055                 {
1056                   next1 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1057                   goto trace01;
1058                 }
1059
1060               if (ip4_is_fragment (ip1))
1061                 {
1062                   next1 = NAT44_ED_OUT2IN_NEXT_REASS;
1063                   goto trace01;
1064                 }
1065
1066               if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
1067                 {
1068                   next1 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1069                   goto trace01;
1070                 }
1071             }
1072
1073           make_ed_kv (&kv1, &ip1->dst_address, &ip1->src_address,
1074                       ip1->protocol, rx_fib_index1, udp1->dst_port,
1075                       udp1->src_port);
1076
1077           if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv1, &value1))
1078             {
1079               if (is_slow_path)
1080                 {
1081                   /* Try to match static mapping by external address and port,
1082                      destination address and port in packet */
1083                   e_key1.addr = ip1->dst_address;
1084                   e_key1.port = udp1->dst_port;
1085                   e_key1.protocol = proto1;
1086                   e_key1.fib_index = rx_fib_index1;
1087                   if (snat_static_mapping_match (sm, e_key1, &l_key1, 1, 0,
1088                                                  &twice_nat1, &lb_nat1,
1089                                                  &ip1->src_address,
1090                                                  &identity_nat1))
1091                     {
1092                       /*
1093                        * Send DHCP packets to the ipv4 stack, or we won't
1094                        * be able to use dhcp client on the outside interface
1095                        */
1096                       if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_UDP
1097                                          && (udp1->dst_port ==
1098                                              clib_host_to_net_u16
1099                                              (UDP_DST_PORT_dhcp_to_client))))
1100                         {
1101                           vnet_feature_next (&next1, b1);
1102                           goto trace01;
1103                         }
1104
1105                       if (!sm->forwarding_enabled)
1106                         {
1107                           b1->error =
1108                             node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
1109                           next1 = NAT44_ED_OUT2IN_NEXT_DROP;
1110                         }
1111                       else
1112                         {
1113                           if (next_src_nat (sm, ip1, ip1->protocol,
1114                                             udp1->src_port, udp1->dst_port,
1115                                             thread_index, rx_fib_index1))
1116                             {
1117                               next1 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
1118                               goto trace01;
1119                             }
1120                           create_bypass_for_fwd (sm, ip1, rx_fib_index1,
1121                                                  thread_index);
1122                         }
1123                       goto trace01;
1124                     }
1125
1126                   if (PREDICT_FALSE (identity_nat1))
1127                     goto trace01;
1128
1129                   if ((proto1 == SNAT_PROTOCOL_TCP) && !tcp_is_init (tcp1))
1130                     {
1131                       b1->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
1132                       next1 = NAT44_ED_OUT2IN_NEXT_DROP;
1133                       goto trace01;
1134                     }
1135
1136                   /* Create session initiated by host from external network */
1137                   s1 = create_session_for_static_mapping_ed (sm, b1, l_key1,
1138                                                              e_key1, node,
1139                                                              thread_index,
1140                                                              twice_nat1,
1141                                                              lb_nat1, now);
1142
1143                   if (!s1)
1144                     {
1145                       next1 = NAT44_ED_OUT2IN_NEXT_DROP;
1146                       goto trace01;
1147                     }
1148                 }
1149               else
1150                 {
1151                   next1 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1152                   goto trace01;
1153                 }
1154             }
1155           else
1156             {
1157               s1 = pool_elt_at_index (tsm->sessions, value1.value);
1158             }
1159
1160           old_addr1 = ip1->dst_address.as_u32;
1161           new_addr1 = ip1->dst_address.as_u32 = s1->in2out.addr.as_u32;
1162           vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1163
1164           sum1 = ip1->checksum;
1165           sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t,
1166                                  dst_address);
1167           if (PREDICT_FALSE (is_twice_nat_session (s1)))
1168             sum1 = ip_csum_update (sum1, ip1->src_address.as_u32,
1169                                    s1->ext_host_nat_addr.as_u32, ip4_header_t,
1170                                    src_address);
1171           ip1->checksum = ip_csum_fold (sum1);
1172
1173           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
1174             {
1175               old_port1 = tcp1->dst_port;
1176               new_port1 = tcp1->dst_port = s1->in2out.port;
1177
1178               sum1 = tcp1->checksum;
1179               sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t,
1180                                      dst_address);
1181               sum1 = ip_csum_update (sum1, old_port1, new_port1, ip4_header_t,
1182                                      length);
1183               if (is_twice_nat_session (s1))
1184                 {
1185                   sum1 = ip_csum_update (sum1, ip1->src_address.as_u32,
1186                                          s1->ext_host_nat_addr.as_u32,
1187                                          ip4_header_t, dst_address);
1188                   sum1 = ip_csum_update (sum1, tcp1->src_port,
1189                                          s1->ext_host_nat_port, ip4_header_t,
1190                                          length);
1191                   tcp1->src_port = s1->ext_host_nat_port;
1192                   ip1->src_address.as_u32 = s1->ext_host_nat_addr.as_u32;
1193                 }
1194               tcp1->checksum = ip_csum_fold (sum1);
1195               if (nat44_set_tcp_session_state_o2i
1196                   (sm, s1, tcp1, thread_index))
1197                 goto trace01;
1198             }
1199           else
1200             {
1201               udp1->dst_port = s1->in2out.port;
1202               if (is_twice_nat_session (s1))
1203                 {
1204                   udp1->src_port = s1->ext_host_nat_port;
1205                   ip1->src_address.as_u32 = s1->ext_host_nat_addr.as_u32;
1206                 }
1207               udp1->checksum = 0;
1208             }
1209
1210           /* Accounting */
1211           nat44_session_update_counters (s1, now,
1212                                          vlib_buffer_length_in_chain (vm,
1213                                                                       b1));
1214           /* Per-user LRU list maintenance */
1215           nat44_session_update_lru (sm, s1, thread_index);
1216
1217         trace01:
1218           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1219                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1220             {
1221               nat44_ed_out2in_trace_t *t =
1222                 vlib_add_trace (vm, node, b1, sizeof (*t));
1223               t->is_slow_path = is_slow_path;
1224               t->sw_if_index = sw_if_index1;
1225               t->next_index = next1;
1226               t->session_index = ~0;
1227               if (s1)
1228                 t->session_index = s1 - tsm->sessions;
1229             }
1230
1231           pkts_processed += next1 != NAT44_ED_OUT2IN_NEXT_DROP;
1232
1233           /* verify speculative enqueues, maybe switch current next frame */
1234           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
1235                                            to_next, n_left_to_next,
1236                                            bi0, bi1, next0, next1);
1237         }
1238
1239       while (n_left_from > 0 && n_left_to_next > 0)
1240         {
1241           u32 bi0;
1242           vlib_buffer_t *b0;
1243           u32 next0, sw_if_index0, rx_fib_index0, proto0, old_addr0,
1244             new_addr0;
1245           u16 old_port0, new_port0;
1246           ip4_header_t *ip0;
1247           udp_header_t *udp0;
1248           tcp_header_t *tcp0;
1249           icmp46_header_t *icmp0;
1250           snat_session_t *s0 = 0;
1251           clib_bihash_kv_16_8_t kv0, value0;
1252           ip_csum_t sum0;
1253           snat_session_key_t e_key0, l_key0;
1254           lb_nat_type_t lb_nat0;
1255           twice_nat_type_t twice_nat0;
1256           u8 identity_nat0;
1257
1258           /* speculatively enqueue b0 to the current next frame */
1259           bi0 = from[0];
1260           to_next[0] = bi0;
1261           from += 1;
1262           to_next += 1;
1263           n_left_from -= 1;
1264           n_left_to_next -= 1;
1265
1266           b0 = vlib_get_buffer (vm, bi0);
1267           next0 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
1268           vnet_buffer (b0)->snat.flags = 0;
1269           ip0 = vlib_buffer_get_current (b0);
1270
1271           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1272           rx_fib_index0 =
1273             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
1274                                                  sw_if_index0);
1275
1276           if (PREDICT_FALSE (ip0->ttl == 1))
1277             {
1278               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1279               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1280                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1281                                            0);
1282               next0 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
1283               goto trace0;
1284             }
1285
1286           udp0 = ip4_next_header (ip0);
1287           tcp0 = (tcp_header_t *) udp0;
1288           icmp0 = (icmp46_header_t *) udp0;
1289           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1290
1291           if (is_slow_path)
1292             {
1293               if (PREDICT_FALSE (proto0 == ~0))
1294                 {
1295                   s0 =
1296                     nat44_ed_out2in_unknown_proto (sm, b0, ip0, rx_fib_index0,
1297                                                    thread_index, now, vm,
1298                                                    node);
1299                   if (!sm->forwarding_enabled)
1300                     {
1301                       if (!s0)
1302                         next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1303                       goto trace0;
1304                     }
1305                 }
1306
1307               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1308                 {
1309                   next0 = icmp_out2in_ed_slow_path
1310                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1311                      next0, now, thread_index, &s0);
1312                   goto trace0;
1313                 }
1314             }
1315           else
1316             {
1317               if (PREDICT_FALSE (proto0 == ~0))
1318                 {
1319                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1320                   goto trace0;
1321                 }
1322
1323               if (ip4_is_fragment (ip0))
1324                 {
1325                   next0 = NAT44_ED_OUT2IN_NEXT_REASS;
1326                   goto trace0;
1327                 }
1328
1329               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1330                 {
1331                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1332                   goto trace0;
1333                 }
1334             }
1335
1336           make_ed_kv (&kv0, &ip0->dst_address, &ip0->src_address,
1337                       ip0->protocol, rx_fib_index0, udp0->dst_port,
1338                       udp0->src_port);
1339
1340           if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv0, &value0))
1341             {
1342               if (is_slow_path)
1343                 {
1344                   /* Try to match static mapping by external address and port,
1345                      destination address and port in packet */
1346                   e_key0.addr = ip0->dst_address;
1347                   e_key0.port = udp0->dst_port;
1348                   e_key0.protocol = proto0;
1349                   e_key0.fib_index = rx_fib_index0;
1350                   if (snat_static_mapping_match (sm, e_key0, &l_key0, 1, 0,
1351                                                  &twice_nat0, &lb_nat0,
1352                                                  &ip0->src_address,
1353                                                  &identity_nat0))
1354                     {
1355                       /*
1356                        * Send DHCP packets to the ipv4 stack, or we won't
1357                        * be able to use dhcp client on the outside interface
1358                        */
1359                       if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
1360                                          && (udp0->dst_port ==
1361                                              clib_host_to_net_u16
1362                                              (UDP_DST_PORT_dhcp_to_client))))
1363                         {
1364                           vnet_feature_next (&next0, b0);
1365                           goto trace0;
1366                         }
1367
1368                       if (!sm->forwarding_enabled)
1369                         {
1370                           b0->error =
1371                             node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
1372                           next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1373                         }
1374                       else
1375                         {
1376                           if (next_src_nat (sm, ip0, ip0->protocol,
1377                                             udp0->src_port, udp0->dst_port,
1378                                             thread_index, rx_fib_index0))
1379                             {
1380                               next0 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
1381                               goto trace0;
1382                             }
1383                           create_bypass_for_fwd (sm, ip0, rx_fib_index0,
1384                                                  thread_index);
1385                         }
1386                       goto trace0;
1387                     }
1388
1389                   if (PREDICT_FALSE (identity_nat0))
1390                     goto trace0;
1391
1392                   if ((proto0 == SNAT_PROTOCOL_TCP) && !tcp_is_init (tcp0))
1393                     {
1394                       b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
1395                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1396                       goto trace0;
1397                     }
1398
1399                   /* Create session initiated by host from external network */
1400                   s0 = create_session_for_static_mapping_ed (sm, b0, l_key0,
1401                                                              e_key0, node,
1402                                                              thread_index,
1403                                                              twice_nat0,
1404                                                              lb_nat0, now);
1405
1406                   if (!s0)
1407                     {
1408                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1409                       goto trace0;
1410                     }
1411                 }
1412               else
1413                 {
1414                   next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
1415                   goto trace0;
1416                 }
1417             }
1418           else
1419             {
1420               s0 = pool_elt_at_index (tsm->sessions, value0.value);
1421             }
1422
1423           old_addr0 = ip0->dst_address.as_u32;
1424           new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
1425           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1426
1427           sum0 = ip0->checksum;
1428           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
1429                                  dst_address);
1430           if (PREDICT_FALSE (is_twice_nat_session (s0)))
1431             sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
1432                                    s0->ext_host_nat_addr.as_u32, ip4_header_t,
1433                                    src_address);
1434           ip0->checksum = ip_csum_fold (sum0);
1435
1436           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1437             {
1438               old_port0 = tcp0->dst_port;
1439               new_port0 = tcp0->dst_port = s0->in2out.port;
1440
1441               sum0 = tcp0->checksum;
1442               sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
1443                                      dst_address);
1444               sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
1445                                      length);
1446               if (is_twice_nat_session (s0))
1447                 {
1448                   sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
1449                                          s0->ext_host_nat_addr.as_u32,
1450                                          ip4_header_t, dst_address);
1451                   sum0 = ip_csum_update (sum0, tcp0->src_port,
1452                                          s0->ext_host_nat_port, ip4_header_t,
1453                                          length);
1454                   tcp0->src_port = s0->ext_host_nat_port;
1455                   ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
1456                 }
1457               tcp0->checksum = ip_csum_fold (sum0);
1458               if (nat44_set_tcp_session_state_o2i
1459                   (sm, s0, tcp0, thread_index))
1460                 goto trace0;
1461             }
1462           else
1463             {
1464               udp0->dst_port = s0->in2out.port;
1465               if (is_twice_nat_session (s0))
1466                 {
1467                   udp0->src_port = s0->ext_host_nat_port;
1468                   ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
1469                 }
1470               udp0->checksum = 0;
1471             }
1472
1473           /* Accounting */
1474           nat44_session_update_counters (s0, now,
1475                                          vlib_buffer_length_in_chain (vm,
1476                                                                       b0));
1477           /* Per-user LRU list maintenance */
1478           nat44_session_update_lru (sm, s0, thread_index);
1479
1480         trace0:
1481           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1482                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1483             {
1484               nat44_ed_out2in_trace_t *t =
1485                 vlib_add_trace (vm, node, b0, sizeof (*t));
1486               t->is_slow_path = is_slow_path;
1487               t->sw_if_index = sw_if_index0;
1488               t->next_index = next0;
1489               t->session_index = ~0;
1490               if (s0)
1491                 t->session_index = s0 - tsm->sessions;
1492             }
1493
1494           pkts_processed += next0 != NAT44_ED_OUT2IN_NEXT_DROP;
1495           /* verify speculative enqueue, maybe switch current next frame */
1496           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1497                                            to_next, n_left_to_next,
1498                                            bi0, next0);
1499         }
1500
1501       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1502     }
1503
1504   vlib_node_increment_counter (vm, stats_node_index,
1505                                NAT_OUT2IN_ED_ERROR_OUT2IN_PACKETS,
1506                                pkts_processed);
1507   return frame->n_vectors;
1508 }
1509
1510 static uword
1511 nat44_ed_out2in_fast_path_fn (vlib_main_t * vm,
1512                               vlib_node_runtime_t * node,
1513                               vlib_frame_t * frame)
1514 {
1515   return nat44_ed_out2in_node_fn_inline (vm, node, frame, 0);
1516 }
1517
1518 /* *INDENT-OFF* */
1519 VLIB_REGISTER_NODE (nat44_ed_out2in_node) = {
1520   .function = nat44_ed_out2in_fast_path_fn,
1521   .name = "nat44-ed-out2in",
1522   .vector_size = sizeof (u32),
1523   .format_trace = format_nat44_ed_out2in_trace,
1524   .type = VLIB_NODE_TYPE_INTERNAL,
1525   .n_errors = ARRAY_LEN(nat_out2in_ed_error_strings),
1526   .error_strings = nat_out2in_ed_error_strings,
1527   .runtime_data_bytes = sizeof (snat_runtime_t),
1528   .n_next_nodes = NAT44_ED_OUT2IN_N_NEXT,
1529   .next_nodes = {
1530     [NAT44_ED_OUT2IN_NEXT_DROP] = "error-drop",
1531     [NAT44_ED_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1532     [NAT44_ED_OUT2IN_NEXT_SLOW_PATH] = "nat44-ed-out2in-slowpath",
1533     [NAT44_ED_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1534     [NAT44_ED_OUT2IN_NEXT_IN2OUT] = "nat44-ed-in2out",
1535     [NAT44_ED_OUT2IN_NEXT_REASS] = "nat44-ed-out2in-reass",
1536   },
1537 };
1538 /* *INDENT-ON* */
1539
1540 VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_out2in_node,
1541                               nat44_ed_out2in_fast_path_fn);
1542
1543 static uword
1544 nat44_ed_out2in_slow_path_fn (vlib_main_t * vm,
1545                               vlib_node_runtime_t * node,
1546                               vlib_frame_t * frame)
1547 {
1548   return nat44_ed_out2in_node_fn_inline (vm, node, frame, 1);
1549 }
1550
1551 /* *INDENT-OFF* */
1552 VLIB_REGISTER_NODE (nat44_ed_out2in_slowpath_node) = {
1553   .function = nat44_ed_out2in_slow_path_fn,
1554   .name = "nat44-ed-out2in-slowpath",
1555   .vector_size = sizeof (u32),
1556   .format_trace = format_nat44_ed_out2in_trace,
1557   .type = VLIB_NODE_TYPE_INTERNAL,
1558   .n_errors = ARRAY_LEN(nat_out2in_ed_error_strings),
1559   .error_strings = nat_out2in_ed_error_strings,
1560   .runtime_data_bytes = sizeof (snat_runtime_t),
1561   .n_next_nodes = NAT44_ED_OUT2IN_N_NEXT,
1562   .next_nodes = {
1563     [NAT44_ED_OUT2IN_NEXT_DROP] = "error-drop",
1564     [NAT44_ED_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1565     [NAT44_ED_OUT2IN_NEXT_SLOW_PATH] = "nat44-ed-out2in-slowpath",
1566     [NAT44_ED_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1567     [NAT44_ED_OUT2IN_NEXT_IN2OUT] = "nat44-ed-in2out",
1568     [NAT44_ED_OUT2IN_NEXT_REASS] = "nat44-ed-out2in-reass",
1569   },
1570 };
1571 /* *INDENT-ON* */
1572
1573 VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_out2in_slowpath_node,
1574                               nat44_ed_out2in_slow_path_fn);
1575
1576 static uword
1577 nat44_ed_out2in_reass_node_fn (vlib_main_t * vm,
1578                                vlib_node_runtime_t * node,
1579                                vlib_frame_t * frame)
1580 {
1581   u32 n_left_from, *from, *to_next;
1582   nat44_ed_out2in_next_t next_index;
1583   u32 pkts_processed = 0;
1584   snat_main_t *sm = &snat_main;
1585   f64 now = vlib_time_now (vm);
1586   u32 thread_index = vm->thread_index;
1587   snat_main_per_thread_data_t *per_thread_data =
1588     &sm->per_thread_data[thread_index];
1589   u32 *fragments_to_drop = 0;
1590   u32 *fragments_to_loopback = 0;
1591
1592   from = vlib_frame_vector_args (frame);
1593   n_left_from = frame->n_vectors;
1594   next_index = node->cached_next_index;
1595
1596   while (n_left_from > 0)
1597     {
1598       u32 n_left_to_next;
1599
1600       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1601
1602       while (n_left_from > 0 && n_left_to_next > 0)
1603         {
1604           u32 bi0, sw_if_index0, proto0, rx_fib_index0, new_addr0, old_addr0;
1605           vlib_buffer_t *b0;
1606           u32 next0;
1607           u8 cached0 = 0;
1608           ip4_header_t *ip0;
1609           nat_reass_ip4_t *reass0;
1610           udp_header_t *udp0;
1611           tcp_header_t *tcp0;
1612           icmp46_header_t *icmp0;
1613           clib_bihash_kv_16_8_t kv0, value0;
1614           snat_session_t *s0 = 0;
1615           u16 old_port0, new_port0;
1616           ip_csum_t sum0;
1617           snat_session_key_t e_key0, l_key0;
1618           lb_nat_type_t lb0;
1619           twice_nat_type_t twice_nat0;
1620           u8 identity_nat0;
1621
1622           /* speculatively enqueue b0 to the current next frame */
1623           bi0 = from[0];
1624           to_next[0] = bi0;
1625           from += 1;
1626           to_next += 1;
1627           n_left_from -= 1;
1628           n_left_to_next -= 1;
1629
1630           b0 = vlib_get_buffer (vm, bi0);
1631           next0 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
1632
1633           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1634           rx_fib_index0 =
1635             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
1636                                                  sw_if_index0);
1637
1638           if (PREDICT_FALSE (nat_reass_is_drop_frag (0)))
1639             {
1640               next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1641               b0->error = node->errors[NAT_OUT2IN_ED_ERROR_DROP_FRAGMENT];
1642               goto trace0;
1643             }
1644
1645           ip0 = (ip4_header_t *) vlib_buffer_get_current (b0);
1646           udp0 = ip4_next_header (ip0);
1647           tcp0 = (tcp_header_t *) udp0;
1648           icmp0 = (icmp46_header_t *) udp0;
1649           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1650
1651           reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
1652                                                  ip0->dst_address,
1653                                                  ip0->fragment_id,
1654                                                  ip0->protocol,
1655                                                  1, &fragments_to_drop);
1656
1657           if (PREDICT_FALSE (!reass0))
1658             {
1659               next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1660               b0->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_REASS];
1661               nat_log_notice ("maximum reassemblies exceeded");
1662               goto trace0;
1663             }
1664
1665           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
1666             {
1667               if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1668                 {
1669                   next0 = icmp_out2in_ed_slow_path
1670                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1671                      next0, now, thread_index, &s0);
1672
1673                   if (PREDICT_TRUE (next0 != NAT44_ED_OUT2IN_NEXT_DROP))
1674                     {
1675                       if (s0)
1676                         reass0->sess_index = s0 - per_thread_data->sessions;
1677                       else
1678                         reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
1679                       reass0->thread_index = thread_index;
1680                       nat_ip4_reass_get_frags (reass0,
1681                                                &fragments_to_loopback);
1682                     }
1683
1684                   goto trace0;
1685                 }
1686
1687               make_ed_kv (&kv0, &ip0->dst_address, &ip0->src_address,
1688                           ip0->protocol, rx_fib_index0, udp0->dst_port,
1689                           udp0->src_port);
1690
1691               if (clib_bihash_search_16_8
1692                   (&per_thread_data->out2in_ed, &kv0, &value0))
1693                 {
1694                   /* Try to match static mapping by external address and port,
1695                      destination address and port in packet */
1696                   e_key0.addr = ip0->dst_address;
1697                   e_key0.port = udp0->dst_port;
1698                   e_key0.protocol = proto0;
1699                   e_key0.fib_index = rx_fib_index0;
1700                   if (snat_static_mapping_match (sm, e_key0, &l_key0, 1, 0,
1701                                                  &twice_nat0, &lb0, 0,
1702                                                  &identity_nat0))
1703                     {
1704                       /*
1705                        * Send DHCP packets to the ipv4 stack, or we won't
1706                        * be able to use dhcp client on the outside interface
1707                        */
1708                       if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
1709                                          && (udp0->dst_port
1710                                              ==
1711                                              clib_host_to_net_u16
1712                                              (UDP_DST_PORT_dhcp_to_client))))
1713                         {
1714                           vnet_feature_next (&next0, b0);
1715                           goto trace0;
1716                         }
1717
1718                       if (!sm->forwarding_enabled)
1719                         {
1720                           b0->error =
1721                             node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
1722                           next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1723                         }
1724                       else
1725                         {
1726                           if (next_src_nat (sm, ip0, ip0->protocol,
1727                                             udp0->src_port, udp0->dst_port,
1728                                             thread_index, rx_fib_index0))
1729                             {
1730                               next0 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
1731                               goto trace0;
1732                             }
1733                           create_bypass_for_fwd (sm, ip0, rx_fib_index0,
1734                                                  thread_index);
1735                           reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
1736                           nat_ip4_reass_get_frags (reass0,
1737                                                    &fragments_to_loopback);
1738                         }
1739                       goto trace0;
1740                     }
1741
1742                   if (PREDICT_FALSE (identity_nat0))
1743                     {
1744                       reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
1745                       goto trace0;
1746                     }
1747
1748                   if ((proto0 == SNAT_PROTOCOL_TCP) && !tcp_is_init (tcp0))
1749                     {
1750                       b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
1751                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1752                       goto trace0;
1753                     }
1754
1755                   /* Create session initiated by host from external network */
1756                   s0 = create_session_for_static_mapping_ed (sm, b0, l_key0,
1757                                                              e_key0, node,
1758                                                              thread_index,
1759                                                              twice_nat0, lb0,
1760                                                              now);
1761                   if (!s0)
1762                     {
1763                       b0->error =
1764                         node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
1765                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1766                       goto trace0;
1767                     }
1768                   reass0->sess_index = s0 - per_thread_data->sessions;
1769                   reass0->thread_index = thread_index;
1770                 }
1771               else
1772                 {
1773                   s0 = pool_elt_at_index (per_thread_data->sessions,
1774                                           value0.value);
1775                   reass0->sess_index = value0.value;
1776                 }
1777               nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
1778             }
1779           else
1780             {
1781               if (reass0->flags & NAT_REASS_FLAG_ED_DONT_TRANSLATE)
1782                 goto trace0;
1783               if (PREDICT_FALSE (reass0->sess_index == (u32) ~ 0))
1784                 {
1785                   if (nat_ip4_reass_add_fragment
1786                       (reass0, bi0, &fragments_to_drop))
1787                     {
1788                       b0->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_FRAG];
1789                       nat_log_notice
1790                         ("maximum fragments per reassembly exceeded");
1791                       next0 = NAT44_ED_OUT2IN_NEXT_DROP;
1792                       goto trace0;
1793                     }
1794                   cached0 = 1;
1795                   goto trace0;
1796                 }
1797               s0 = pool_elt_at_index (per_thread_data->sessions,
1798                                       reass0->sess_index);
1799             }
1800
1801           old_addr0 = ip0->dst_address.as_u32;
1802           ip0->dst_address = s0->in2out.addr;
1803           new_addr0 = ip0->dst_address.as_u32;
1804           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1805
1806           sum0 = ip0->checksum;
1807           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1808                                  ip4_header_t,
1809                                  dst_address /* changed member */ );
1810           if (PREDICT_FALSE (is_twice_nat_session (s0)))
1811             sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
1812                                    s0->ext_host_nat_addr.as_u32, ip4_header_t,
1813                                    src_address);
1814           ip0->checksum = ip_csum_fold (sum0);
1815
1816           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
1817             {
1818               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1819                 {
1820                   old_port0 = tcp0->dst_port;
1821                   tcp0->dst_port = s0->in2out.port;
1822                   new_port0 = tcp0->dst_port;
1823
1824                   sum0 = tcp0->checksum;
1825                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1826                                          ip4_header_t,
1827                                          dst_address /* changed member */ );
1828
1829                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1830                                          ip4_header_t /* cheat */ ,
1831                                          length /* changed member */ );
1832                   if (is_twice_nat_session (s0))
1833                     {
1834                       sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
1835                                              s0->ext_host_nat_addr.as_u32,
1836                                              ip4_header_t, dst_address);
1837                       sum0 = ip_csum_update (sum0, tcp0->src_port,
1838                                              s0->ext_host_nat_port,
1839                                              ip4_header_t, length);
1840                       tcp0->src_port = s0->ext_host_nat_port;
1841                       ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
1842                     }
1843                   tcp0->checksum = ip_csum_fold (sum0);
1844                 }
1845               else
1846                 {
1847                   old_port0 = udp0->dst_port;
1848                   udp0->dst_port = s0->in2out.port;
1849                   if (is_twice_nat_session (s0))
1850                     {
1851                       udp0->src_port = s0->ext_host_nat_port;
1852                       ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
1853                     }
1854                   udp0->checksum = 0;
1855                 }
1856             }
1857
1858           /* Accounting */
1859           nat44_session_update_counters (s0, now,
1860                                          vlib_buffer_length_in_chain (vm,
1861                                                                       b0));
1862           /* Per-user LRU list maintenance */
1863           nat44_session_update_lru (sm, s0, thread_index);
1864
1865         trace0:
1866           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1867                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1868             {
1869               nat44_reass_trace_t *t =
1870                 vlib_add_trace (vm, node, b0, sizeof (*t));
1871               t->cached = cached0;
1872               t->sw_if_index = sw_if_index0;
1873               t->next_index = next0;
1874             }
1875
1876           if (cached0)
1877             {
1878               n_left_to_next++;
1879               to_next--;
1880             }
1881           else
1882             {
1883               pkts_processed += next0 != NAT44_ED_OUT2IN_NEXT_DROP;
1884
1885               /* verify speculative enqueue, maybe switch current next frame */
1886               vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1887                                                to_next, n_left_to_next,
1888                                                bi0, next0);
1889             }
1890
1891           if (n_left_from == 0 && vec_len (fragments_to_loopback))
1892             {
1893               from = vlib_frame_vector_args (frame);
1894               u32 len = vec_len (fragments_to_loopback);
1895               if (len <= VLIB_FRAME_SIZE)
1896                 {
1897                   clib_memcpy_fast (from, fragments_to_loopback,
1898                                     sizeof (u32) * len);
1899                   n_left_from = len;
1900                   vec_reset_length (fragments_to_loopback);
1901                 }
1902               else
1903                 {
1904                   clib_memcpy_fast (from, fragments_to_loopback +
1905                                     (len - VLIB_FRAME_SIZE),
1906                                     sizeof (u32) * VLIB_FRAME_SIZE);
1907                   n_left_from = VLIB_FRAME_SIZE;
1908                   _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
1909                 }
1910             }
1911         }
1912
1913       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1914     }
1915
1916   vlib_node_increment_counter (vm, nat44_ed_out2in_reass_node.index,
1917                                NAT_OUT2IN_ED_ERROR_OUT2IN_PACKETS,
1918                                pkts_processed);
1919
1920   nat_send_all_to_node (vm, fragments_to_drop, node,
1921                         &node->errors[NAT_OUT2IN_ED_ERROR_DROP_FRAGMENT],
1922                         NAT44_ED_OUT2IN_NEXT_DROP);
1923
1924   vec_free (fragments_to_drop);
1925   vec_free (fragments_to_loopback);
1926   return frame->n_vectors;
1927 }
1928
1929 /* *INDENT-OFF* */
1930 VLIB_REGISTER_NODE (nat44_ed_out2in_reass_node) = {
1931   .function = nat44_ed_out2in_reass_node_fn,
1932   .name = "nat44-ed-out2in-reass",
1933   .vector_size = sizeof (u32),
1934   .format_trace = format_nat44_reass_trace,
1935   .type = VLIB_NODE_TYPE_INTERNAL,
1936   .n_errors = ARRAY_LEN(nat_out2in_ed_error_strings),
1937   .error_strings = nat_out2in_ed_error_strings,
1938   .n_next_nodes = NAT44_ED_OUT2IN_N_NEXT,
1939   .next_nodes = {
1940     [NAT44_ED_OUT2IN_NEXT_DROP] = "error-drop",
1941     [NAT44_ED_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1942     [NAT44_ED_OUT2IN_NEXT_SLOW_PATH] = "nat44-ed-out2in-slowpath",
1943     [NAT44_ED_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1944     [NAT44_ED_OUT2IN_NEXT_IN2OUT] = "nat44-ed-in2out",
1945     [NAT44_ED_OUT2IN_NEXT_REASS] = "nat44-ed-out2in-reass",
1946   },
1947 };
1948 /* *INDENT-ON* */
1949
1950 VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_out2in_reass_node,
1951                               nat44_ed_out2in_reass_node_fn);
1952
1953 /*
1954  * fd.io coding-style-patch-verification: ON
1955  *
1956  * Local Variables:
1957  * eval: (c-set-style "gnu")
1958  * End:
1959  */