src/plugins/nat/out2in.c

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 /**
  16  * @file
  17  * @brief NAT44 endpoint-dependent outside to inside network translation
  18  */
  19
  20 #include <vlib/vlib.h>
  21 #include <vnet/vnet.h>
  22
  23 #include <vnet/ip/ip.h>
  24 #include <vnet/udp/udp_local.h>
  25 #include <vnet/ethernet/ethernet.h>
  26 #include <vnet/fib/ip4_fib.h>
  27 #include <nat/nat.h>
  28 #include <nat/lib/ipfix_logging.h>
  29 #include <nat/nat_inlines.h>
  30 #include <nat/nat44/inlines.h>
  31 #include <nat/lib/nat_syslog.h>
  32 #include <nat/nat_ha.h>
  33
  34 #include <vppinfra/hash.h>
  35 #include <vppinfra/error.h>
  36 #include <vppinfra/elog.h>
  37
  38 typedef struct
  39 {
  40   u32 sw_if_index;
  41   u32 next_index;
  42   u32 session_index;
  43 } snat_out2in_trace_t;
  44
  45 /* packet trace format function */
  46 static u8 *
  47 format_snat_out2in_trace (u8 * s, va_list * args)
  48 {
  49   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  50   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  51   snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
  52
  53   s =
  54     format (s,
  55             "NAT44_OUT2IN: sw_if_index %d, next index %d, session index %d",
  56             t->sw_if_index, t->next_index, t->session_index);
  57   return s;
  58 }
  59
  60 static u8 *
  61 format_snat_out2in_fast_trace (u8 * s, va_list * args)
  62 {
  63   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  64   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  65   snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
  66
  67   s = format (s, "NAT44_OUT2IN_FAST: sw_if_index %d, next index %d",
  68               t->sw_if_index, t->next_index);
  69   return s;
  70 }
  71
  72 #define foreach_snat_out2in_error                       \
  73 _(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
  74 _(OUT_OF_PORTS, "out of ports")                         \
  75 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  76 _(NO_TRANSLATION, "no translation")                     \
  77 _(MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")   \
  78 _(CANNOT_CREATE_USER, "cannot create NAT user")
  79
  80 typedef enum
  81 {
  82 #define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
  83   foreach_snat_out2in_error
  84 #undef _
  85     SNAT_OUT2IN_N_ERROR,
  86 } snat_out2in_error_t;
  87
  88 static char *snat_out2in_error_strings[] = {
  89 #define _(sym,string) string,
  90   foreach_snat_out2in_error
  91 #undef _
  92 };
  93
  94 typedef enum
  95 {
  96   SNAT_OUT2IN_NEXT_DROP,
  97   SNAT_OUT2IN_NEXT_LOOKUP,
  98   SNAT_OUT2IN_NEXT_ICMP_ERROR,
  99   SNAT_OUT2IN_N_NEXT,
 100 } snat_out2in_next_t;
 101
 102 #ifndef CLIB_MARCH_VARIANT
 103 int
 104 nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 105 {
 106   snat_main_t *sm = &snat_main;
 107   nat44_is_idle_session_ctx_t *ctx = arg;
 108   snat_session_t *s;
 109   u64 sess_timeout_time;
 110   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
 111                                                        ctx->thread_index);
 112   clib_bihash_kv_8_8_t s_kv;
 113
 114   s = pool_elt_at_index (tsm->sessions, kv->value);
 115   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
 116   if (ctx->now >= sess_timeout_time)
 117     {
 118       init_nat_i2o_k (&s_kv, s);
 119       if (clib_bihash_add_del_8_8 (&tsm->in2out, &s_kv, 0))
 120         nat_elog_warn ("out2in key del failed");
 121
 122       nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
 123                                           s->in2out.addr.as_u32,
 124                                           s->out2in.addr.as_u32,
 125                                           s->nat_proto,
 126                                           s->in2out.port,
 127                                           s->out2in.port,
 128                                           s->in2out.fib_index);
 129
 130       nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
 131                                &s->in2out.addr, s->in2out.port,
 132                                &s->out2in.addr, s->out2in.port, s->nat_proto);
 133
 134       nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
 135                    s->ext_host_port, s->nat_proto, s->out2in.fib_index,
 136                    ctx->thread_index);
 137
 138       if (!snat_is_session_static (s))
 139         snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
 140                                             &s->out2in.addr, s->out2in.port,
 141                                             s->nat_proto);
 142
 143       nat44_delete_session (sm, s, ctx->thread_index);
 144       return 1;
 145     }
 146
 147   return 0;
 148 }
 149 #endif
 150
 151 /**
 152  * @brief Create session for static mapping.
 153  *
 154  * Create NAT session initiated by host from external network with static
 155  * mapping.
 156  *
 157  * @param sm     NAT main.
 158  * @param b0     Vlib buffer.
 159  * @param in2out In2out NAT44 session key.
 160  * @param out2in Out2in NAT44 session key.
 161  * @param node   Vlib node.
 162  *
 163  * @returns SNAT session if successfully created otherwise 0.
 164  */
 165 static inline snat_session_t *
 166 create_session_for_static_mapping (snat_main_t * sm,
 167                                    vlib_buffer_t * b0,
 168                                    ip4_address_t i2o_addr,
 169                                    u16 i2o_port,
 170                                    u32 i2o_fib_index,
 171                                    ip4_address_t o2i_addr,
 172                                    u16 o2i_port,
 173                                    u32 o2i_fib_index,
 174                                    nat_protocol_t proto,
 175                                    vlib_node_runtime_t * node,
 176                                    u32 thread_index, f64 now)
 177 {
 178   snat_user_t *u;
 179   snat_session_t *s;
 180   clib_bihash_kv_8_8_t kv0;
 181   ip4_header_t *ip0;
 182   udp_header_t *udp0;
 183   nat44_is_idle_session_ctx_t ctx0;
 184
 185   if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
 186     {
 187       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
 188       nat_elog_notice ("maximum sessions exceeded");
 189       return 0;
 190     }
 191
 192   ip0 = vlib_buffer_get_current (b0);
 193   udp0 = ip4_next_header (ip0);
 194
 195   u = nat_user_get_or_create (sm, &i2o_addr, i2o_fib_index, thread_index);
 196   if (!u)
 197     {
 198       b0->error = node->errors[SNAT_OUT2IN_ERROR_CANNOT_CREATE_USER];
 199       return 0;
 200     }
 201
 202   s = nat_session_alloc_or_recycle (sm, u, thread_index, now);
 203   if (!s)
 204     {
 205       nat44_delete_user_with_no_session (sm, u, thread_index);
 206       nat_elog_warn ("create NAT session failed");
 207       return 0;
 208     }
 209
 210   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 211   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
 212   s->ext_host_port = udp0->src_port;
 213   user_session_increment (sm, u, 1 /* static */ );
 214   s->in2out.addr = i2o_addr;
 215   s->in2out.port = i2o_port;
 216   s->in2out.fib_index = i2o_fib_index;
 217   s->out2in.addr = o2i_addr;
 218   s->out2in.port = o2i_port;
 219   s->out2in.fib_index = o2i_fib_index;
 220   s->nat_proto = proto;
 221
 222   /* Add to translation hashes */
 223   ctx0.now = now;
 224   ctx0.thread_index = thread_index;
 225   init_nat_i2o_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
 226   if (clib_bihash_add_or_overwrite_stale_8_8
 227       (&sm->per_thread_data[thread_index].in2out, &kv0,
 228        nat44_i2o_is_idle_session_cb, &ctx0))
 229     nat_elog_notice ("in2out key add failed");
 230
 231   init_nat_o2i_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
 232   if (clib_bihash_add_or_overwrite_stale_8_8
 233       (&sm->per_thread_data[thread_index].out2in, &kv0,
 234        nat44_o2i_is_idle_session_cb, &ctx0))
 235     nat_elog_notice ("out2in key add failed");
 236
 237   /* log NAT event */
 238   nat_ipfix_logging_nat44_ses_create (thread_index,
 239                                       s->in2out.addr.as_u32,
 240                                       s->out2in.addr.as_u32,
 241                                       s->nat_proto,
 242                                       s->in2out.port,
 243                                       s->out2in.port, s->in2out.fib_index);
 244
 245   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
 246                            &s->in2out.addr, s->in2out.port, &s->out2in.addr,
 247                            s->out2in.port, s->nat_proto);
 248
 249   nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
 250                s->out2in.port, &s->ext_host_addr, s->ext_host_port,
 251                &s->ext_host_nat_addr, s->ext_host_nat_port,
 252                s->nat_proto, s->in2out.fib_index, s->flags, thread_index, 0);
 253
 254   return s;
 255 }
 256
 257 #ifndef CLIB_MARCH_VARIANT
 258 static_always_inline snat_out2in_error_t
 259 icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
 260               ip4_address_t * addr, u16 * port, nat_protocol_t * nat_proto)
 261 {
 262   icmp46_header_t *icmp0;
 263   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 264   ip4_header_t *inner_ip0;
 265   void *l4_header = 0;
 266   icmp46_header_t *inner_icmp0;
 267
 268   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 269   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 270
 271   if (!icmp_type_is_error_message
 272       (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
 273     {
 274       *nat_proto = NAT_PROTOCOL_ICMP;
 275       *addr = ip0->dst_address;
 276       *port = vnet_buffer (b)->ip.reass.l4_src_port;
 277     }
 278   else
 279     {
 280       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 281       l4_header = ip4_next_header (inner_ip0);
 282       *nat_proto = ip_proto_to_nat_proto (inner_ip0->protocol);
 283       *addr = inner_ip0->src_address;
 284       switch (*nat_proto)
 285         {
 286         case NAT_PROTOCOL_ICMP:
 287           inner_icmp0 = (icmp46_header_t *) l4_header;
 288           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 289           *port = inner_echo0->identifier;
 290           break;
 291         case NAT_PROTOCOL_UDP:
 292         case NAT_PROTOCOL_TCP:
 293           *port = ((tcp_udp_header_t *) l4_header)->src_port;
 294           break;
 295         default:
 296           return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
 297         }
 298     }
 299   return -1;                    /* success */
 300 }
 301
 302 /**
 303  * Get address and port values to be used for ICMP packet translation
 304  * and create session if needed
 305  *
 306  * @param[in,out] sm             NAT main
 307  * @param[in,out] node           NAT node runtime
 308  * @param[in] thread_index       thread index
 309  * @param[in,out] b0             buffer containing packet to be translated
 310  * @param[in,out] ip0            ip header
 311  * @param[out] p_proto           protocol used for matching
 312  * @param[out] p_value           address and port after NAT translation
 313  * @param[out] p_dont_translate  if packet should not be translated
 314  * @param d                      optional parameter
 315  * @param e                      optional parameter
 316  */
 317 u32
 318 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 319                         u32 thread_index, vlib_buffer_t * b0,
 320                         ip4_header_t * ip0, ip4_address_t * addr,
 321                         u16 * port, u32 * fib_index,
 322                         nat_protocol_t * proto, void *d, void *e,
 323                         u8 * dont_translate)
 324 {
 325   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 326   u32 sw_if_index0;
 327   snat_session_t *s0 = 0;
 328   clib_bihash_kv_8_8_t kv0, value0;
 329   u8 is_addr_only;
 330   u32 next0 = ~0;
 331   int err;
 332   u8 identity_nat;
 333   vlib_main_t *vm = vlib_get_main ();
 334   *dont_translate = 0;
 335
 336   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 337   *fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 338
 339   *proto = 0;
 340
 341   err = icmp_get_key (b0, ip0, addr, port, proto);
 342   if (err != -1)
 343     {
 344       b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 345       next0 = SNAT_OUT2IN_NEXT_DROP;
 346       goto out;
 347     }
 348
 349   ip4_address_t mapping_addr;
 350   u16 mapping_port;
 351   u32 mapping_fib_index;
 352
 353   init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
 354   if (clib_bihash_search_8_8 (&tsm->out2in, &kv0, &value0))
 355     {
 356       /* Try to match static mapping by external address and port,
 357          destination address and port in packet */
 358       if (snat_static_mapping_match
 359           (sm, *addr, *port, *fib_index, *proto,
 360            &mapping_addr, &mapping_port, &mapping_fib_index, 1, &is_addr_only,
 361            0, 0, 0, &identity_nat, 0))
 362         {
 363           if (!sm->forwarding_enabled)
 364             {
 365               /* Don't NAT packet aimed at the intfc address */
 366               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 367                                                     ip0->dst_address.as_u32)))
 368                 {
 369                   *dont_translate = 1;
 370                   goto out;
 371                 }
 372               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 373               next0 = SNAT_OUT2IN_NEXT_DROP;
 374               goto out;
 375             }
 376           else
 377             {
 378               *dont_translate = 1;
 379               goto out;
 380             }
 381         }
 382
 383       if (PREDICT_FALSE
 384           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 385            ICMP4_echo_reply
 386            && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 387                ICMP4_echo_request || !is_addr_only)))
 388         {
 389           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 390           next0 = SNAT_OUT2IN_NEXT_DROP;
 391           goto out;
 392         }
 393
 394       if (PREDICT_FALSE (identity_nat))
 395         {
 396           *dont_translate = 1;
 397           goto out;
 398         }
 399       /* Create session initiated by host from external network */
 400       s0 =
 401         create_session_for_static_mapping (sm, b0, mapping_addr, mapping_port,
 402                                            mapping_fib_index, *addr, *port,
 403                                            *fib_index, *proto, node,
 404                                            thread_index, vlib_time_now (vm));
 405
 406       if (!s0)
 407         {
 408           next0 = SNAT_OUT2IN_NEXT_DROP;
 409           goto out;
 410         }
 411     }
 412   else
 413     {
 414       if (PREDICT_FALSE
 415           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 416            ICMP4_echo_reply
 417            && vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 418            ICMP4_echo_request
 419            && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 420                                            reass.icmp_type_or_tcp_flags)))
 421         {
 422           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 423           next0 = SNAT_OUT2IN_NEXT_DROP;
 424           goto out;
 425         }
 426
 427       s0 = pool_elt_at_index (tsm->sessions, value0.value);
 428     }
 429
 430 out:
 431   if (s0)
 432     {
 433       *addr = s0->in2out.addr;
 434       *port = s0->in2out.port;
 435       *fib_index = s0->in2out.fib_index;
 436     }
 437   if (d)
 438     *(snat_session_t **) d = s0;
 439   return next0;
 440 }
 441 #endif
 442
 443 #ifndef CLIB_MARCH_VARIANT
 444 /**
 445  * Get address and port values to be used for ICMP packet translation
 446  *
 447  * @param[in] sm                 NAT main
 448  * @param[in,out] node           NAT node runtime
 449  * @param[in] thread_index       thread index
 450  * @param[in,out] b0             buffer containing packet to be translated
 451  * @param[in,out] ip0            ip header
 452  * @param[out] p_proto           protocol used for matching
 453  * @param[out] p_value           address and port after NAT translation
 454  * @param[out] p_dont_translate  if packet should not be translated
 455  * @param d                      optional parameter
 456  * @param e                      optional parameter
 457  */
 458 u32
 459 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
 460                         u32 thread_index, vlib_buffer_t * b0,
 461                         ip4_header_t * ip0, ip4_address_t * mapping_addr,
 462                         u16 * mapping_port, u32 * mapping_fib_index,
 463                         nat_protocol_t * proto, void *d, void *e,
 464                         u8 * dont_translate)
 465 {
 466   u32 sw_if_index0;
 467   u32 rx_fib_index0;
 468   u8 is_addr_only;
 469   u32 next0 = ~0;
 470   int err;
 471   ip4_address_t addr;
 472   u16 port;
 473   *dont_translate = 0;
 474
 475   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 476   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 477
 478   err = icmp_get_key (b0, ip0, &addr, &port, proto);
 479   if (err != -1)
 480     {
 481       b0->error = node->errors[err];
 482       next0 = SNAT_OUT2IN_NEXT_DROP;
 483       goto out;
 484     }
 485   if (snat_static_mapping_match
 486       (sm, addr, port, rx_fib_index0, *proto, mapping_addr, mapping_port,
 487        mapping_fib_index, 1, &is_addr_only, 0, 0, 0, 0, 0))
 488     {
 489       /* Don't NAT packet aimed at the intfc address */
 490       if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
 491         {
 492           *dont_translate = 1;
 493           goto out;
 494         }
 495       b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 496       next0 = SNAT_OUT2IN_NEXT_DROP;
 497       goto out;
 498     }
 499
 500   if (PREDICT_FALSE
 501       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
 502        && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 503            ICMP4_echo_request || !is_addr_only)
 504        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 505                                        reass.icmp_type_or_tcp_flags)))
 506     {
 507       b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 508       next0 = SNAT_OUT2IN_NEXT_DROP;
 509       goto out;
 510     }
 511
 512 out:
 513   return next0;
 514 }
 515 #endif
 516
 517 #ifndef CLIB_MARCH_VARIANT
 518 u32
 519 icmp_out2in (snat_main_t * sm,
 520              vlib_buffer_t * b0,
 521              ip4_header_t * ip0,
 522              icmp46_header_t * icmp0,
 523              u32 sw_if_index0,
 524              u32 rx_fib_index0,
 525              vlib_node_runtime_t * node,
 526              u32 next0, u32 thread_index, void *d, void *e)
 527 {
 528   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 529   ip4_header_t *inner_ip0 = 0;
 530   void *l4_header = 0;
 531   icmp46_header_t *inner_icmp0;
 532   u8 dont_translate;
 533   u32 new_addr0, old_addr0;
 534   u16 old_id0, new_id0;
 535   ip_csum_t sum0;
 536   u16 checksum0;
 537   u32 next0_tmp;
 538   vlib_main_t *vm = vlib_get_main ();
 539   ip4_address_t addr;
 540   u16 port;
 541   u32 fib_index;
 542   nat_protocol_t proto;
 543
 544   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 545
 546   next0_tmp = sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0,
 547                                         &addr, &port, &fib_index, &proto,
 548                                         d, e, &dont_translate);
 549   if (next0_tmp != ~0)
 550     next0 = next0_tmp;
 551   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
 552     goto out;
 553
 554   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 555     {
 556       sum0 =
 557         ip_incremental_checksum_buffer (vm, b0,
 558                                         (u8 *) icmp0 -
 559                                         (u8 *) vlib_buffer_get_current (b0),
 560                                         ntohs (ip0->length) -
 561                                         ip4_header_bytes (ip0), 0);
 562       checksum0 = ~ip_csum_fold (sum0);
 563       if (checksum0 != 0 && checksum0 != 0xffff)
 564         {
 565           next0 = SNAT_OUT2IN_NEXT_DROP;
 566           goto out;
 567         }
 568     }
 569
 570   old_addr0 = ip0->dst_address.as_u32;
 571   new_addr0 = ip0->dst_address.as_u32 = addr.as_u32;
 572   vnet_buffer (b0)->sw_if_index[VLIB_TX] = fib_index;
 573
 574   sum0 = ip0->checksum;
 575   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 576                          dst_address /* changed member */ );
 577   ip0->checksum = ip_csum_fold (sum0);
 578
 579
 580   if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 581     {
 582       if (icmp0->checksum == 0)
 583         icmp0->checksum = 0xffff;
 584
 585       if (!icmp_type_is_error_message (icmp0->type))
 586         {
 587           new_id0 = port;
 588           if (PREDICT_FALSE (new_id0 != echo0->identifier))
 589             {
 590               old_id0 = echo0->identifier;
 591               new_id0 = port;
 592               echo0->identifier = new_id0;
 593
 594               sum0 = icmp0->checksum;
 595               sum0 =
 596                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 597                                 identifier /* changed member */ );
 598               icmp0->checksum = ip_csum_fold (sum0);
 599             }
 600         }
 601       else
 602         {
 603           inner_ip0 = (ip4_header_t *) (echo0 + 1);
 604           l4_header = ip4_next_header (inner_ip0);
 605
 606           if (!ip4_header_checksum_is_valid (inner_ip0))
 607             {
 608               next0 = SNAT_OUT2IN_NEXT_DROP;
 609               goto out;
 610             }
 611
 612           old_addr0 = inner_ip0->src_address.as_u32;
 613           inner_ip0->src_address = addr;
 614           new_addr0 = inner_ip0->src_address.as_u32;
 615
 616           sum0 = icmp0->checksum;
 617           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 618                                  src_address /* changed member */ );
 619           icmp0->checksum = ip_csum_fold (sum0);
 620
 621           switch (proto)
 622             {
 623             case NAT_PROTOCOL_ICMP:
 624               inner_icmp0 = (icmp46_header_t *) l4_header;
 625               inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 626
 627               old_id0 = inner_echo0->identifier;
 628               new_id0 = port;
 629               inner_echo0->identifier = new_id0;
 630
 631               sum0 = icmp0->checksum;
 632               sum0 =
 633                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 634                                 identifier);
 635               icmp0->checksum = ip_csum_fold (sum0);
 636               break;
 637             case NAT_PROTOCOL_UDP:
 638             case NAT_PROTOCOL_TCP:
 639               old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 640               new_id0 = port;
 641               ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 642
 643               sum0 = icmp0->checksum;
 644               sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 645                                      src_port);
 646               icmp0->checksum = ip_csum_fold (sum0);
 647               break;
 648             default:
 649               ASSERT (0);
 650             }
 651         }
 652     }
 653
 654 out:
 655   return next0;
 656 }
 657 #endif
 658
 659 static inline u32
 660 icmp_out2in_slow_path (snat_main_t * sm,
 661                        vlib_buffer_t * b0,
 662                        ip4_header_t * ip0,
 663                        icmp46_header_t * icmp0,
 664                        u32 sw_if_index0,
 665                        u32 rx_fib_index0,
 666                        vlib_node_runtime_t * node,
 667                        u32 next0, f64 now,
 668                        u32 thread_index, snat_session_t ** p_s0)
 669 {
 670   vlib_main_t *vm = vlib_get_main ();
 671
 672   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 673                        next0, thread_index, p_s0, 0);
 674   snat_session_t *s0 = *p_s0;
 675   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
 676     {
 677       /* Accounting */
 678       nat44_session_update_counters (s0, now,
 679                                      vlib_buffer_length_in_chain
 680                                      (vm, b0), thread_index);
 681       /* Per-user LRU list maintenance */
 682       nat44_session_update_lru (sm, s0, thread_index);
 683     }
 684   return next0;
 685 }
 686
 687 static int
 688 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 689                              vlib_buffer_t * b,
 690                              ip4_header_t * ip, u32 rx_fib_index)
 691 {
 692   clib_bihash_kv_8_8_t kv, value;
 693   snat_static_mapping_t *m;
 694   u32 old_addr, new_addr;
 695   ip_csum_t sum;
 696
 697   init_nat_k (&kv, ip->dst_address, 0, 0, 0);
 698   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 699     return 1;
 700
 701   m = pool_elt_at_index (sm->static_mappings, value.value);
 702
 703   old_addr = ip->dst_address.as_u32;
 704   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 705   sum = ip->checksum;
 706   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 707   ip->checksum = ip_csum_fold (sum);
 708
 709   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 710   return 0;
 711 }
 712
 713 VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 714                                  vlib_node_runtime_t * node,
 715                                  vlib_frame_t * frame)
 716 {
 717   u32 n_left_from, *from;
 718   snat_main_t *sm = &snat_main;
 719   f64 now = vlib_time_now (vm);
 720   u32 thread_index = vm->thread_index;
 721   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 722
 723   from = vlib_frame_vector_args (frame);
 724   n_left_from = frame->n_vectors;
 725
 726   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
 727   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 728   vlib_get_buffers (vm, from, b, n_left_from);
 729
 730   while (n_left_from >= 2)
 731     {
 732       vlib_buffer_t *b0, *b1;
 733       u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 734       u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 735       u32 sw_if_index0, sw_if_index1;
 736       ip4_header_t *ip0, *ip1;
 737       ip_csum_t sum0, sum1;
 738       u32 new_addr0, old_addr0;
 739       u16 new_port0, old_port0;
 740       u32 new_addr1, old_addr1;
 741       u16 new_port1, old_port1;
 742       udp_header_t *udp0, *udp1;
 743       tcp_header_t *tcp0, *tcp1;
 744       icmp46_header_t *icmp0, *icmp1;
 745       u32 rx_fib_index0, rx_fib_index1;
 746       u32 proto0, proto1;
 747       snat_session_t *s0 = 0, *s1 = 0;
 748       clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
 749       u8 identity_nat0, identity_nat1;
 750       ip4_address_t sm_addr0, sm_addr1;
 751       u16 sm_port0, sm_port1;
 752       u32 sm_fib_index0, sm_fib_index1;
 753
 754       b0 = *b;
 755       b++;
 756       b1 = *b;
 757       b++;
 758
 759       /* Prefetch next iteration. */
 760       if (PREDICT_TRUE (n_left_from >= 4))
 761         {
 762           vlib_buffer_t *p2, *p3;
 763
 764           p2 = *b;
 765           p3 = *(b + 1);
 766
 767           vlib_prefetch_buffer_header (p2, LOAD);
 768           vlib_prefetch_buffer_header (p3, LOAD);
 769
 770           CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
 771           CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
 772         }
 773
 774       vnet_buffer (b0)->snat.flags = 0;
 775       vnet_buffer (b1)->snat.flags = 0;
 776
 777       ip0 = vlib_buffer_get_current (b0);
 778       udp0 = ip4_next_header (ip0);
 779       tcp0 = (tcp_header_t *) udp0;
 780       icmp0 = (icmp46_header_t *) udp0;
 781
 782       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 783       rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 784                                sw_if_index0);
 785
 786       if (PREDICT_FALSE (ip0->ttl == 1))
 787         {
 788           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 789           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 790                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 791                                        0);
 792           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 793           goto trace0;
 794         }
 795
 796       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 797
 798       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 799         {
 800           if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 801             {
 802               if (!sm->forwarding_enabled)
 803                 {
 804                   b0->error =
 805                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 806                   next0 = SNAT_OUT2IN_NEXT_DROP;
 807                 }
 808             }
 809           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
 810                                          thread_index, sw_if_index0, 1);
 811
 812           goto trace0;
 813         }
 814
 815       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 816         {
 817           next0 = icmp_out2in_slow_path
 818             (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 819              next0, now, thread_index, &s0);
 820           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
 821                                          thread_index, sw_if_index0, 1);
 822           goto trace0;
 823         }
 824
 825       init_nat_k (&kv0, ip0->dst_address,
 826                   vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 827                   proto0);
 828       if (clib_bihash_search_8_8
 829           (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
 830         {
 831           /* Try to match static mapping by external address and port,
 832              destination address and port in packet */
 833           if (snat_static_mapping_match
 834               (sm, ip0->dst_address,
 835                vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 836                proto0, &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
 837                0, &identity_nat0, 0))
 838             {
 839               /*
 840                * Send DHCP packets to the ipv4 stack, or we won't
 841                * be able to use dhcp client on the outside interface
 842                */
 843               if (PREDICT_FALSE
 844                   (proto0 == NAT_PROTOCOL_UDP
 845                    && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
 846                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
 847                 {
 848                   vnet_feature_next (&next0, b0);
 849                   goto trace0;
 850                 }
 851
 852               if (!sm->forwarding_enabled)
 853                 {
 854                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 855                   next0 = SNAT_OUT2IN_NEXT_DROP;
 856                 }
 857               goto trace0;
 858             }
 859
 860           if (PREDICT_FALSE (identity_nat0))
 861             goto trace0;
 862
 863           /* Create session initiated by host from external network */
 864           s0 = create_session_for_static_mapping (sm, b0,
 865                                                   sm_addr0, sm_port0,
 866                                                   sm_fib_index0,
 867                                                   ip0->dst_address,
 868                                                   vnet_buffer (b0)->ip.
 869                                                   reass.l4_dst_port,
 870                                                   rx_fib_index0, proto0, node,
 871                                                   thread_index, now);
 872           if (!s0)
 873             {
 874               next0 = SNAT_OUT2IN_NEXT_DROP;
 875               goto trace0;
 876             }
 877         }
 878       else
 879         s0 = pool_elt_at_index (tsm->sessions, value0.value);
 880
 881       old_addr0 = ip0->dst_address.as_u32;
 882       ip0->dst_address = s0->in2out.addr;
 883       new_addr0 = ip0->dst_address.as_u32;
 884       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 885
 886       sum0 = ip0->checksum;
 887       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 888                              ip4_header_t, dst_address /* changed member */ );
 889       ip0->checksum = ip_csum_fold (sum0);
 890
 891       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 892         {
 893           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 894             {
 895               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 896               new_port0 = udp0->dst_port = s0->in2out.port;
 897               sum0 = tcp0->checksum;
 898               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 899                                      ip4_header_t,
 900                                      dst_address /* changed member */ );
 901
 902               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 903                                      ip4_header_t /* cheat */ ,
 904                                      length /* changed member */ );
 905               tcp0->checksum = ip_csum_fold (sum0);
 906             }
 907           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
 908                                          thread_index, sw_if_index0, 1);
 909         }
 910       else
 911         {
 912           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 913             {
 914               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 915               new_port0 = udp0->dst_port = s0->in2out.port;
 916               if (PREDICT_FALSE (udp0->checksum))
 917                 {
 918                   sum0 = udp0->checksum;
 919                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
 920                     );
 921                   sum0 =
 922                     ip_csum_update (sum0, old_port0, new_port0,
 923                                     ip4_header_t /* cheat */ ,
 924                                     length /* changed member */ );
 925                   udp0->checksum = ip_csum_fold (sum0);
 926                 }
 927             }
 928           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
 929                                          thread_index, sw_if_index0, 1);
 930         }
 931
 932       /* Accounting */
 933       nat44_session_update_counters (s0, now,
 934                                      vlib_buffer_length_in_chain (vm, b0),
 935                                      thread_index);
 936       /* Per-user LRU list maintenance */
 937       nat44_session_update_lru (sm, s0, thread_index);
 938     trace0:
 939
 940       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 941                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 942         {
 943           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
 944           t->sw_if_index = sw_if_index0;
 945           t->next_index = next0;
 946           t->session_index = ~0;
 947           if (s0)
 948             t->session_index =
 949               s0 - sm->per_thread_data[thread_index].sessions;
 950         }
 951
 952       if (next0 == SNAT_OUT2IN_NEXT_DROP)
 953         {
 954           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
 955                                          thread_index, sw_if_index0, 1);
 956         }
 957
 958
 959       ip1 = vlib_buffer_get_current (b1);
 960       udp1 = ip4_next_header (ip1);
 961       tcp1 = (tcp_header_t *) udp1;
 962       icmp1 = (icmp46_header_t *) udp1;
 963
 964       sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 965       rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 966                                sw_if_index1);
 967
 968       if (PREDICT_FALSE (ip1->ttl == 1))
 969         {
 970           vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 971           icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 972                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 973                                        0);
 974           next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 975           goto trace1;
 976         }
 977
 978       proto1 = ip_proto_to_nat_proto (ip1->protocol);
 979
 980       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
 981         {
 982           if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
 983             {
 984               if (!sm->forwarding_enabled)
 985                 {
 986                   b1->error =
 987                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 988                   next1 = SNAT_OUT2IN_NEXT_DROP;
 989                 }
 990             }
 991           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
 992                                          thread_index, sw_if_index1, 1);
 993           goto trace1;
 994         }
 995
 996       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 997         {
 998           next1 = icmp_out2in_slow_path
 999             (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
1000              next1, now, thread_index, &s1);
1001           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
1002                                          thread_index, sw_if_index1, 1);
1003           goto trace1;
1004         }
1005
1006       init_nat_k (&kv1, ip1->dst_address,
1007                   vnet_buffer (b1)->ip.reass.l4_dst_port, rx_fib_index1,
1008                   proto1);
1009
1010       if (clib_bihash_search_8_8
1011           (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
1012         {
1013           /* Try to match static mapping by external address and port,
1014              destination address and port in packet */
1015           if (snat_static_mapping_match
1016               (sm, ip1->dst_address,
1017                vnet_buffer (b1)->ip.reass.l4_dst_port, proto1,
1018                rx_fib_index1, &sm_addr1, &sm_port1, &sm_fib_index1, 1, 0,
1019                0, 0, 0, &identity_nat1, 0))
1020             {
1021               /*
1022                * Send DHCP packets to the ipv4 stack, or we won't
1023                * be able to use dhcp client on the outside interface
1024                */
1025               if (PREDICT_FALSE
1026                   (proto1 == NAT_PROTOCOL_UDP
1027                    && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
1028                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
1029                 {
1030                   vnet_feature_next (&next1, b1);
1031                   goto trace1;
1032                 }
1033
1034               if (!sm->forwarding_enabled)
1035                 {
1036                   b1->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1037                   next1 = SNAT_OUT2IN_NEXT_DROP;
1038                 }
1039               goto trace1;
1040             }
1041
1042           if (PREDICT_FALSE (identity_nat1))
1043             goto trace1;
1044
1045           /* Create session initiated by host from external network */
1046           s1 =
1047             create_session_for_static_mapping (sm, b1, sm_addr1, sm_port1,
1048                                                sm_fib_index1,
1049                                                ip1->dst_address,
1050                                                vnet_buffer (b1)->ip.
1051                                                reass.l4_dst_port,
1052                                                rx_fib_index1, proto1, node,
1053                                                thread_index, now);
1054           if (!s1)
1055             {
1056               next1 = SNAT_OUT2IN_NEXT_DROP;
1057               goto trace1;
1058             }
1059         }
1060       else
1061         s1 =
1062           pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1063                              value1.value);
1064
1065       old_addr1 = ip1->dst_address.as_u32;
1066       ip1->dst_address = s1->in2out.addr;
1067       new_addr1 = ip1->dst_address.as_u32;
1068       vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1069
1070       sum1 = ip1->checksum;
1071       sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1072                              ip4_header_t, dst_address /* changed member */ );
1073       ip1->checksum = ip_csum_fold (sum1);
1074
1075       if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
1076         {
1077           if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1078             {
1079               old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1080               new_port1 = udp1->dst_port = s1->in2out.port;
1081
1082               sum1 = tcp1->checksum;
1083               sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1084                                      ip4_header_t,
1085                                      dst_address /* changed member */ );
1086
1087               sum1 = ip_csum_update (sum1, old_port1, new_port1,
1088                                      ip4_header_t /* cheat */ ,
1089                                      length /* changed member */ );
1090               tcp1->checksum = ip_csum_fold (sum1);
1091             }
1092           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
1093                                          thread_index, sw_if_index1, 1);
1094         }
1095       else
1096         {
1097           if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1098             {
1099               old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1100               new_port1 = udp1->dst_port = s1->in2out.port;
1101               if (PREDICT_FALSE (udp1->checksum))
1102                 {
1103
1104                   sum1 = udp1->checksum;
1105                   sum1 =
1106                     ip_csum_update (sum1, old_addr1, new_addr1,
1107                                     ip4_header_t,
1108                                     dst_address /* changed member */ );
1109                   sum1 =
1110                     ip_csum_update (sum1, old_port1, new_port1,
1111                                     ip4_header_t /* cheat */ ,
1112                                     length /* changed member */ );
1113                   udp1->checksum = ip_csum_fold (sum1);
1114                 }
1115             }
1116           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
1117                                          thread_index, sw_if_index1, 1);
1118         }
1119
1120       /* Accounting */
1121       nat44_session_update_counters (s1, now,
1122                                      vlib_buffer_length_in_chain (vm, b1),
1123                                      thread_index);
1124       /* Per-user LRU list maintenance */
1125       nat44_session_update_lru (sm, s1, thread_index);
1126     trace1:
1127
1128       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1129                          && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1130         {
1131           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b1, sizeof (*t));
1132           t->sw_if_index = sw_if_index1;
1133           t->next_index = next1;
1134           t->session_index = ~0;
1135           if (s1)
1136             t->session_index =
1137               s1 - sm->per_thread_data[thread_index].sessions;
1138         }
1139
1140       if (next1 == SNAT_OUT2IN_NEXT_DROP)
1141         {
1142           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
1143                                          thread_index, sw_if_index1, 1);
1144         }
1145
1146       n_left_from -= 2;
1147       next[0] = next0;
1148       next[1] = next1;
1149       next += 2;
1150     }
1151
1152   while (n_left_from > 0)
1153     {
1154       vlib_buffer_t *b0;
1155       u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1156       u32 sw_if_index0;
1157       ip4_header_t *ip0;
1158       ip_csum_t sum0;
1159       u32 new_addr0, old_addr0;
1160       u16 new_port0, old_port0;
1161       udp_header_t *udp0;
1162       tcp_header_t *tcp0;
1163       icmp46_header_t *icmp0;
1164       u32 rx_fib_index0;
1165       u32 proto0;
1166       snat_session_t *s0 = 0;
1167       clib_bihash_kv_8_8_t kv0, value0;
1168       u8 identity_nat0;
1169       ip4_address_t sm_addr0;
1170       u16 sm_port0;
1171       u32 sm_fib_index0;
1172
1173       b0 = *b;
1174       ++b;
1175
1176       vnet_buffer (b0)->snat.flags = 0;
1177
1178       ip0 = vlib_buffer_get_current (b0);
1179       udp0 = ip4_next_header (ip0);
1180       tcp0 = (tcp_header_t *) udp0;
1181       icmp0 = (icmp46_header_t *) udp0;
1182
1183       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1184       rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1185                                sw_if_index0);
1186
1187       proto0 = ip_proto_to_nat_proto (ip0->protocol);
1188
1189       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1190         {
1191           if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1192             {
1193               if (!sm->forwarding_enabled)
1194                 {
1195                   b0->error =
1196                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1197                   next0 = SNAT_OUT2IN_NEXT_DROP;
1198                 }
1199             }
1200           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
1201                                          thread_index, sw_if_index0, 1);
1202           goto trace00;
1203         }
1204
1205       if (PREDICT_FALSE (ip0->ttl == 1))
1206         {
1207           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1208           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1209                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
1210                                        0);
1211           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1212           goto trace00;
1213         }
1214
1215       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1216         {
1217           next0 = icmp_out2in_slow_path
1218             (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1219              next0, now, thread_index, &s0);
1220           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
1221                                          thread_index, sw_if_index0, 1);
1222           goto trace00;
1223         }
1224
1225       init_nat_k (&kv0, ip0->dst_address,
1226                   vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
1227                   proto0);
1228
1229       if (clib_bihash_search_8_8
1230           (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
1231         {
1232           /* Try to match static mapping by external address and port,
1233              destination address and port in packet */
1234           if (snat_static_mapping_match
1235               (sm, ip0->dst_address,
1236                vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
1237                proto0, &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
1238                0, &identity_nat0, 0))
1239             {
1240               /*
1241                * Send DHCP packets to the ipv4 stack, or we won't
1242                * be able to use dhcp client on the outside interface
1243                */
1244               if (PREDICT_FALSE
1245                   (proto0 == NAT_PROTOCOL_UDP
1246                    && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
1247                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
1248                 {
1249                   vnet_feature_next (&next0, b0);
1250                   goto trace00;
1251                 }
1252
1253               if (!sm->forwarding_enabled)
1254                 {
1255                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1256                   next0 = SNAT_OUT2IN_NEXT_DROP;
1257                 }
1258               goto trace00;
1259             }
1260
1261           if (PREDICT_FALSE (identity_nat0))
1262             goto trace00;
1263
1264           /* Create session initiated by host from external network */
1265           s0 = create_session_for_static_mapping (sm, b0,
1266                                                   sm_addr0, sm_port0,
1267                                                   sm_fib_index0,
1268                                                   ip0->dst_address,
1269                                                   vnet_buffer (b0)->ip.
1270                                                   reass.l4_dst_port,
1271                                                   rx_fib_index0, proto0, node,
1272                                                   thread_index, now);
1273           if (!s0)
1274             {
1275               next0 = SNAT_OUT2IN_NEXT_DROP;
1276               goto trace00;
1277             }
1278         }
1279       else
1280         s0 =
1281           pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1282                              value0.value);
1283
1284       old_addr0 = ip0->dst_address.as_u32;
1285       ip0->dst_address = s0->in2out.addr;
1286       new_addr0 = ip0->dst_address.as_u32;
1287       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1288
1289       sum0 = ip0->checksum;
1290       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1291                              ip4_header_t, dst_address /* changed member */ );
1292       ip0->checksum = ip_csum_fold (sum0);
1293
1294       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1295         {
1296           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1297             {
1298               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1299               new_port0 = udp0->dst_port = s0->in2out.port;
1300
1301               sum0 = tcp0->checksum;
1302               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1303                                      ip4_header_t,
1304                                      dst_address /* changed member */ );
1305
1306               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1307                                      ip4_header_t /* cheat */ ,
1308                                      length /* changed member */ );
1309               tcp0->checksum = ip_csum_fold (sum0);
1310             }
1311           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
1312                                          thread_index, sw_if_index0, 1);
1313         }
1314       else
1315         {
1316           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1317             {
1318               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1319               new_port0 = udp0->dst_port = s0->in2out.port;
1320               if (PREDICT_FALSE (udp0->checksum))
1321                 {
1322                   sum0 = udp0->checksum;
1323                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
1324                     );
1325                   sum0 =
1326                     ip_csum_update (sum0, old_port0, new_port0,
1327                                     ip4_header_t /* cheat */ ,
1328                                     length /* changed member */ );
1329                   udp0->checksum = ip_csum_fold (sum0);
1330                 }
1331             }
1332           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
1333                                          thread_index, sw_if_index0, 1);
1334         }
1335
1336       /* Accounting */
1337       nat44_session_update_counters (s0, now,
1338                                      vlib_buffer_length_in_chain (vm, b0),
1339                                      thread_index);
1340       /* Per-user LRU list maintenance */
1341       nat44_session_update_lru (sm, s0, thread_index);
1342     trace00:
1343
1344       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1345                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1346         {
1347           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
1348           t->sw_if_index = sw_if_index0;
1349           t->next_index = next0;
1350           t->session_index = ~0;
1351           if (s0)
1352             t->session_index =
1353               s0 - sm->per_thread_data[thread_index].sessions;
1354         }
1355
1356       if (next0 == SNAT_OUT2IN_NEXT_DROP)
1357         {
1358           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
1359                                          thread_index, sw_if_index0, 1);
1360         }
1361
1362       n_left_from--;
1363       next[0] = next0;
1364       next++;
1365     }
1366
1367   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
1368                                frame->n_vectors);
1369
1370   return frame->n_vectors;
1371 }
1372
1373 /* *INDENT-OFF* */
1374 VLIB_REGISTER_NODE (snat_out2in_node) = {
1375   .name = "nat44-out2in",
1376   .vector_size = sizeof (u32),
1377   .format_trace = format_snat_out2in_trace,
1378   .type = VLIB_NODE_TYPE_INTERNAL,
1379
1380   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1381   .error_strings = snat_out2in_error_strings,
1382
1383   .runtime_data_bytes = sizeof (snat_runtime_t),
1384
1385   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1386
1387   /* edit / add dispositions here */
1388   .next_nodes = {
1389     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1390     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1391     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1392   },
1393 };
1394 /* *INDENT-ON* */
1395
1396 VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
1397                                       vlib_node_runtime_t * node,
1398                                       vlib_frame_t * frame)
1399 {
1400   u32 n_left_from, *from;
1401   snat_main_t *sm = &snat_main;
1402
1403   from = vlib_frame_vector_args (frame);
1404   n_left_from = frame->n_vectors;
1405
1406   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
1407   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
1408   vlib_get_buffers (vm, from, b, n_left_from);
1409   while (n_left_from > 0)
1410     {
1411       vlib_buffer_t *b0;
1412       u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1413       u32 sw_if_index0;
1414       ip4_header_t *ip0;
1415       ip_csum_t sum0;
1416       u32 new_addr0, old_addr0;
1417       u16 new_port0, old_port0;
1418       udp_header_t *udp0;
1419       tcp_header_t *tcp0;
1420       icmp46_header_t *icmp0;
1421       u32 proto0;
1422       u32 rx_fib_index0;
1423       ip4_address_t sm_addr0;
1424       u16 sm_port0;
1425       u32 sm_fib_index0;
1426
1427       b0 = *b;
1428       b++;
1429
1430       ip0 = vlib_buffer_get_current (b0);
1431       udp0 = ip4_next_header (ip0);
1432       tcp0 = (tcp_header_t *) udp0;
1433       icmp0 = (icmp46_header_t *) udp0;
1434
1435       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1436       rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1437
1438       vnet_feature_next (&next0, b0);
1439
1440       if (PREDICT_FALSE (ip0->ttl == 1))
1441         {
1442           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1443           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1444                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
1445                                        0);
1446           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1447           goto trace00;
1448         }
1449
1450       proto0 = ip_proto_to_nat_proto (ip0->protocol);
1451
1452       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1453         goto trace00;
1454
1455       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1456         {
1457           next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1458                                rx_fib_index0, node, next0, ~0, 0, 0);
1459           goto trace00;
1460         }
1461
1462       if (snat_static_mapping_match
1463           (sm, ip0->dst_address, udp0->dst_port, rx_fib_index0, proto0,
1464            &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0, 0, 0, 0))
1465         {
1466           b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1467           goto trace00;
1468         }
1469
1470       new_addr0 = sm_addr0.as_u32;
1471       new_port0 = sm_port0;
1472       vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm_fib_index0;
1473       old_addr0 = ip0->dst_address.as_u32;
1474       ip0->dst_address.as_u32 = new_addr0;
1475
1476       sum0 = ip0->checksum;
1477       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1478                              ip4_header_t, dst_address /* changed member */ );
1479       ip0->checksum = ip_csum_fold (sum0);
1480
1481       if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1482         {
1483           old_port0 = udp0->dst_port;
1484           udp0->dst_port = new_port0;
1485
1486           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1487             {
1488               sum0 = tcp0->checksum;
1489               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1490                                      ip4_header_t,
1491                                      dst_address /* changed member */ );
1492               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1493                                      ip4_header_t /* cheat */ ,
1494                                      length /* changed member */ );
1495               tcp0->checksum = ip_csum_fold (sum0);
1496             }
1497           else if (udp0->checksum)
1498             {
1499               sum0 = udp0->checksum;
1500               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1501                                      ip4_header_t,
1502                                      dst_address /* changed member */ );
1503               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1504                                      ip4_header_t /* cheat */ ,
1505                                      length /* changed member */ );
1506               udp0->checksum = ip_csum_fold (sum0);
1507             }
1508         }
1509       else
1510         {
1511           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1512             {
1513               sum0 = tcp0->checksum;
1514               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1515                                      ip4_header_t,
1516                                      dst_address /* changed member */ );
1517               tcp0->checksum = ip_csum_fold (sum0);
1518             }
1519           else if (udp0->checksum)
1520             {
1521               sum0 = udp0->checksum;
1522               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1523                                      ip4_header_t,
1524                                      dst_address /* changed member */ );
1525               udp0->checksum = ip_csum_fold (sum0);
1526             }
1527         }
1528
1529     trace00:
1530
1531       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1532                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1533         {
1534           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
1535           t->sw_if_index = sw_if_index0;
1536           t->next_index = next0;
1537         }
1538
1539       if (next0 == SNAT_OUT2IN_NEXT_DROP)
1540         {
1541           vlib_increment_simple_counter (&sm->counters.fastpath.out2in.drops,
1542                                          vm->thread_index, sw_if_index0, 1);
1543         }
1544
1545       n_left_from--;
1546       next[0] = next0;
1547       next++;
1548     }
1549
1550   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
1551                                frame->n_vectors);
1552
1553   return frame->n_vectors;
1554 }
1555
1556 /* *INDENT-OFF* */
1557 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1558   .name = "nat44-out2in-fast",
1559   .vector_size = sizeof (u32),
1560   .format_trace = format_snat_out2in_fast_trace,
1561   .type = VLIB_NODE_TYPE_INTERNAL,
1562
1563   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1564   .error_strings = snat_out2in_error_strings,
1565
1566   .runtime_data_bytes = sizeof (snat_runtime_t),
1567
1568   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1569
1570   /* edit / add dispositions here */
1571   .next_nodes = {
1572     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1573     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1574     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1575   },
1576 };
1577 /* *INDENT-ON* */
1578
1579 /*
1580  * fd.io coding-style-patch-verification: ON
1581  *
1582  * Local Variables:
1583  * eval: (c-set-style "gnu")
1584  * End:
1585  */