src/plugins/nat/nat44-ei/nat44_ei_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/lib/nat_syslog.h>
  31 #include <nat/nat44-ei/nat44_ei_inlines.h>
  32
  33 #include <vppinfra/hash.h>
  34 #include <vppinfra/error.h>
  35 #include <vppinfra/elog.h>
  36
  37 typedef struct
  38 {
  39   u32 sw_if_index;
  40   u32 next_index;
  41   u32 session_index;
  42 } snat_out2in_trace_t;
  43
  44 /* packet trace format function */
  45 static u8 *
  46 format_snat_out2in_trace (u8 * s, va_list * args)
  47 {
  48   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  49   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  50   snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
  51
  52   s =
  53     format (s,
  54             "NAT44_OUT2IN: sw_if_index %d, next index %d, session index %d",
  55             t->sw_if_index, t->next_index, t->session_index);
  56   return s;
  57 }
  58
  59 static u8 *
  60 format_snat_out2in_fast_trace (u8 * s, va_list * args)
  61 {
  62   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  63   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  64   snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
  65
  66   s = format (s, "NAT44_OUT2IN_FAST: sw_if_index %d, next index %d",
  67               t->sw_if_index, t->next_index);
  68   return s;
  69 }
  70
  71 #define foreach_snat_out2in_error                       \
  72 _(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
  73 _(OUT_OF_PORTS, "out of ports")                         \
  74 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  75 _(NO_TRANSLATION, "no translation")                     \
  76 _(MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")   \
  77 _(CANNOT_CREATE_USER, "cannot create NAT user")
  78
  79 typedef enum
  80 {
  81 #define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
  82   foreach_snat_out2in_error
  83 #undef _
  84     SNAT_OUT2IN_N_ERROR,
  85 } snat_out2in_error_t;
  86
  87 static char *snat_out2in_error_strings[] = {
  88 #define _(sym,string) string,
  89   foreach_snat_out2in_error
  90 #undef _
  91 };
  92
  93 typedef enum
  94 {
  95   SNAT_OUT2IN_NEXT_DROP,
  96   SNAT_OUT2IN_NEXT_LOOKUP,
  97   SNAT_OUT2IN_NEXT_ICMP_ERROR,
  98   SNAT_OUT2IN_N_NEXT,
  99 } snat_out2in_next_t;
 100
 101 #ifndef CLIB_MARCH_VARIANT
 102 int
 103 nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 104 {
 105   snat_main_t *sm = &snat_main;
 106   nat44_is_idle_session_ctx_t *ctx = arg;
 107   snat_session_t *s;
 108   u64 sess_timeout_time;
 109   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
 110                                                        ctx->thread_index);
 111   clib_bihash_kv_8_8_t s_kv;
 112
 113   s = pool_elt_at_index (tsm->sessions, kv->value);
 114   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
 115   if (ctx->now >= sess_timeout_time)
 116     {
 117       init_nat_i2o_k (&s_kv, s);
 118       if (clib_bihash_add_del_8_8 (&tsm->in2out, &s_kv, 0))
 119         nat_elog_warn ("out2in key del failed");
 120
 121       nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
 122                                           s->in2out.addr.as_u32,
 123                                           s->out2in.addr.as_u32,
 124                                           s->nat_proto,
 125                                           s->in2out.port,
 126                                           s->out2in.port,
 127                                           s->in2out.fib_index);
 128
 129       nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
 130                                &s->in2out.addr, s->in2out.port,
 131                                &s->out2in.addr, s->out2in.port, s->nat_proto);
 132
 133       nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
 134                    s->ext_host_port, s->nat_proto, s->out2in.fib_index,
 135                    ctx->thread_index);
 136
 137       if (!snat_is_session_static (s))
 138         snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
 139                                             &s->out2in.addr, s->out2in.port,
 140                                             s->nat_proto);
 141
 142       nat44_delete_session (sm, s, ctx->thread_index);
 143       return 1;
 144     }
 145
 146   return 0;
 147 }
 148 #endif
 149
 150 /**
 151  * @brief Create session for static mapping.
 152  *
 153  * Create NAT session initiated by host from external network with static
 154  * mapping.
 155  *
 156  * @param sm     NAT main.
 157  * @param b0     Vlib buffer.
 158  * @param in2out In2out NAT44 session key.
 159  * @param out2in Out2in NAT44 session key.
 160  * @param node   Vlib node.
 161  *
 162  * @returns SNAT session if successfully created otherwise 0.
 163  */
 164 static inline snat_session_t *
 165 create_session_for_static_mapping (snat_main_t * sm,
 166                                    vlib_buffer_t * b0,
 167                                    ip4_address_t i2o_addr,
 168                                    u16 i2o_port,
 169                                    u32 i2o_fib_index,
 170                                    ip4_address_t o2i_addr,
 171                                    u16 o2i_port,
 172                                    u32 o2i_fib_index,
 173                                    nat_protocol_t proto,
 174                                    vlib_node_runtime_t * node,
 175                                    u32 thread_index, f64 now)
 176 {
 177   snat_user_t *u;
 178   snat_session_t *s;
 179   clib_bihash_kv_8_8_t kv0;
 180   ip4_header_t *ip0;
 181   udp_header_t *udp0;
 182   nat44_is_idle_session_ctx_t ctx0;
 183
 184   if (PREDICT_FALSE (nat44_ei_maximum_sessions_exceeded (sm, thread_index)))
 185     {
 186       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
 187       nat_elog_notice ("maximum sessions exceeded");
 188       return 0;
 189     }
 190
 191   ip0 = vlib_buffer_get_current (b0);
 192   udp0 = ip4_next_header (ip0);
 193
 194   u = nat_user_get_or_create (sm, &i2o_addr, i2o_fib_index, thread_index);
 195   if (!u)
 196     {
 197       b0->error = node->errors[SNAT_OUT2IN_ERROR_CANNOT_CREATE_USER];
 198       return 0;
 199     }
 200
 201   s = nat_session_alloc_or_recycle (sm, u, thread_index, now);
 202   if (!s)
 203     {
 204       nat44_delete_user_with_no_session (sm, u, thread_index);
 205       nat_elog_warn ("create NAT session failed");
 206       return 0;
 207     }
 208
 209   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 210   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
 211   s->ext_host_port = udp0->src_port;
 212   user_session_increment (sm, u, 1 /* static */ );
 213   s->in2out.addr = i2o_addr;
 214   s->in2out.port = i2o_port;
 215   s->in2out.fib_index = i2o_fib_index;
 216   s->out2in.addr = o2i_addr;
 217   s->out2in.port = o2i_port;
 218   s->out2in.fib_index = o2i_fib_index;
 219   s->nat_proto = proto;
 220
 221   /* Add to translation hashes */
 222   ctx0.now = now;
 223   ctx0.thread_index = thread_index;
 224   init_nat_i2o_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
 225   if (clib_bihash_add_or_overwrite_stale_8_8
 226       (&sm->per_thread_data[thread_index].in2out, &kv0,
 227        nat44_i2o_is_idle_session_cb, &ctx0))
 228     nat_elog_notice ("in2out key add failed");
 229
 230   init_nat_o2i_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
 231   if (clib_bihash_add_or_overwrite_stale_8_8
 232       (&sm->per_thread_data[thread_index].out2in, &kv0,
 233        nat44_o2i_is_idle_session_cb, &ctx0))
 234     nat_elog_notice ("out2in key add failed");
 235
 236   /* log NAT event */
 237   nat_ipfix_logging_nat44_ses_create (thread_index,
 238                                       s->in2out.addr.as_u32,
 239                                       s->out2in.addr.as_u32,
 240                                       s->nat_proto,
 241                                       s->in2out.port,
 242                                       s->out2in.port, s->in2out.fib_index);
 243
 244   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
 245                            &s->in2out.addr, s->in2out.port, &s->out2in.addr,
 246                            s->out2in.port, s->nat_proto);
 247
 248   nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
 249                s->out2in.port, &s->ext_host_addr, s->ext_host_port,
 250                &s->ext_host_nat_addr, s->ext_host_nat_port,
 251                s->nat_proto, s->in2out.fib_index, s->flags, thread_index, 0);
 252
 253   return s;
 254 }
 255
 256 #ifndef CLIB_MARCH_VARIANT
 257 static_always_inline snat_out2in_error_t
 258 icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
 259               ip4_address_t * addr, u16 * port, nat_protocol_t * nat_proto)
 260 {
 261   icmp46_header_t *icmp0;
 262   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 263   ip4_header_t *inner_ip0;
 264   void *l4_header = 0;
 265   icmp46_header_t *inner_icmp0;
 266
 267   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 268   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 269
 270   if (!icmp_type_is_error_message
 271       (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
 272     {
 273       *nat_proto = NAT_PROTOCOL_ICMP;
 274       *addr = ip0->dst_address;
 275       *port = vnet_buffer (b)->ip.reass.l4_src_port;
 276     }
 277   else
 278     {
 279       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 280       l4_header = ip4_next_header (inner_ip0);
 281       *nat_proto = ip_proto_to_nat_proto (inner_ip0->protocol);
 282       *addr = inner_ip0->src_address;
 283       switch (*nat_proto)
 284         {
 285         case NAT_PROTOCOL_ICMP:
 286           inner_icmp0 = (icmp46_header_t *) l4_header;
 287           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 288           *port = inner_echo0->identifier;
 289           break;
 290         case NAT_PROTOCOL_UDP:
 291         case NAT_PROTOCOL_TCP:
 292           *port = ((tcp_udp_header_t *) l4_header)->src_port;
 293           break;
 294         default:
 295           return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
 296         }
 297     }
 298   return -1;                    /* success */
 299 }
 300
 301 /**
 302  * Get address and port values to be used for ICMP packet translation
 303  * and create session if needed
 304  *
 305  * @param[in,out] sm             NAT main
 306  * @param[in,out] node           NAT node runtime
 307  * @param[in] thread_index       thread index
 308  * @param[in,out] b0             buffer containing packet to be translated
 309  * @param[in,out] ip0            ip header
 310  * @param[out] p_proto           protocol used for matching
 311  * @param[out] p_value           address and port after NAT translation
 312  * @param[out] p_dont_translate  if packet should not be translated
 313  * @param d                      optional parameter
 314  * @param e                      optional parameter
 315  */
 316 u32
 317 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 318                         u32 thread_index, vlib_buffer_t * b0,
 319                         ip4_header_t * ip0, ip4_address_t * addr,
 320                         u16 * port, u32 * fib_index,
 321                         nat_protocol_t * proto, void *d, void *e,
 322                         u8 * dont_translate)
 323 {
 324   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 325   u32 sw_if_index0;
 326   snat_session_t *s0 = 0;
 327   clib_bihash_kv_8_8_t kv0, value0;
 328   u8 is_addr_only;
 329   u32 next0 = ~0;
 330   int err;
 331   u8 identity_nat;
 332   vlib_main_t *vm = vlib_get_main ();
 333   *dont_translate = 0;
 334
 335   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 336   *fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 337
 338   *proto = 0;
 339
 340   err = icmp_get_key (b0, ip0, addr, port, proto);
 341   if (err != -1)
 342     {
 343       b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 344       next0 = SNAT_OUT2IN_NEXT_DROP;
 345       goto out;
 346     }
 347
 348   ip4_address_t mapping_addr;
 349   u16 mapping_port;
 350   u32 mapping_fib_index;
 351
 352   init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
 353   if (clib_bihash_search_8_8 (&tsm->out2in, &kv0, &value0))
 354     {
 355       /* Try to match static mapping by external address and port,
 356          destination address and port in packet */
 357       if (snat_static_mapping_match
 358           (sm, *addr, *port, *fib_index, *proto,
 359            &mapping_addr, &mapping_port, &mapping_fib_index, 1, &is_addr_only,
 360            0, 0, 0, &identity_nat, 0))
 361         {
 362           if (!sm->forwarding_enabled)
 363             {
 364               /* Don't NAT packet aimed at the intfc address */
 365               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 366                                                     ip0->dst_address.as_u32)))
 367                 {
 368                   *dont_translate = 1;
 369                   goto out;
 370                 }
 371               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 372               next0 = SNAT_OUT2IN_NEXT_DROP;
 373               goto out;
 374             }
 375           else
 376             {
 377               *dont_translate = 1;
 378               goto out;
 379             }
 380         }
 381
 382       if (PREDICT_FALSE
 383           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 384            ICMP4_echo_reply
 385            && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 386                ICMP4_echo_request || !is_addr_only)))
 387         {
 388           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 389           next0 = SNAT_OUT2IN_NEXT_DROP;
 390           goto out;
 391         }
 392
 393       if (PREDICT_FALSE (identity_nat))
 394         {
 395           *dont_translate = 1;
 396           goto out;
 397         }
 398       /* Create session initiated by host from external network */
 399       s0 =
 400         create_session_for_static_mapping (sm, b0, mapping_addr, mapping_port,
 401                                            mapping_fib_index, *addr, *port,
 402                                            *fib_index, *proto, node,
 403                                            thread_index, vlib_time_now (vm));
 404
 405       if (!s0)
 406         {
 407           next0 = SNAT_OUT2IN_NEXT_DROP;
 408           goto out;
 409         }
 410     }
 411   else
 412     {
 413       if (PREDICT_FALSE
 414           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 415            ICMP4_echo_reply
 416            && vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 417            ICMP4_echo_request
 418            && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 419                                            reass.icmp_type_or_tcp_flags)))
 420         {
 421           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 422           next0 = SNAT_OUT2IN_NEXT_DROP;
 423           goto out;
 424         }
 425
 426       s0 = pool_elt_at_index (tsm->sessions, value0.value);
 427     }
 428
 429 out:
 430   if (s0)
 431     {
 432       *addr = s0->in2out.addr;
 433       *port = s0->in2out.port;
 434       *fib_index = s0->in2out.fib_index;
 435     }
 436   if (d)
 437     *(snat_session_t **) d = s0;
 438   return next0;
 439 }
 440 #endif
 441
 442 #ifndef CLIB_MARCH_VARIANT
 443 /**
 444  * Get address and port values to be used for ICMP packet translation
 445  *
 446  * @param[in] sm                 NAT main
 447  * @param[in,out] node           NAT node runtime
 448  * @param[in] thread_index       thread index
 449  * @param[in,out] b0             buffer containing packet to be translated
 450  * @param[in,out] ip0            ip header
 451  * @param[out] p_proto           protocol used for matching
 452  * @param[out] p_value           address and port after NAT translation
 453  * @param[out] p_dont_translate  if packet should not be translated
 454  * @param d                      optional parameter
 455  * @param e                      optional parameter
 456  */
 457 u32
 458 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
 459                         u32 thread_index, vlib_buffer_t * b0,
 460                         ip4_header_t * ip0, ip4_address_t * mapping_addr,
 461                         u16 * mapping_port, u32 * mapping_fib_index,
 462                         nat_protocol_t * proto, void *d, void *e,
 463                         u8 * dont_translate)
 464 {
 465   u32 sw_if_index0;
 466   u32 rx_fib_index0;
 467   u8 is_addr_only;
 468   u32 next0 = ~0;
 469   int err;
 470   ip4_address_t addr;
 471   u16 port;
 472   *dont_translate = 0;
 473
 474   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 475   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 476
 477   err = icmp_get_key (b0, ip0, &addr, &port, proto);
 478   if (err != -1)
 479     {
 480       b0->error = node->errors[err];
 481       next0 = SNAT_OUT2IN_NEXT_DROP;
 482       goto out;
 483     }
 484   if (snat_static_mapping_match
 485       (sm, addr, port, rx_fib_index0, *proto, mapping_addr, mapping_port,
 486        mapping_fib_index, 1, &is_addr_only, 0, 0, 0, 0, 0))
 487     {
 488       /* Don't NAT packet aimed at the intfc address */
 489       if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
 490         {
 491           *dont_translate = 1;
 492           goto out;
 493         }
 494       b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 495       next0 = SNAT_OUT2IN_NEXT_DROP;
 496       goto out;
 497     }
 498
 499   if (PREDICT_FALSE
 500       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
 501        && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 502            ICMP4_echo_request || !is_addr_only)
 503        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 504                                        reass.icmp_type_or_tcp_flags)))
 505     {
 506       b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 507       next0 = SNAT_OUT2IN_NEXT_DROP;
 508       goto out;
 509     }
 510
 511 out:
 512   return next0;
 513 }
 514 #endif
 515
 516 #ifndef CLIB_MARCH_VARIANT
 517 u32
 518 icmp_out2in (snat_main_t * sm,
 519              vlib_buffer_t * b0,
 520              ip4_header_t * ip0,
 521              icmp46_header_t * icmp0,
 522              u32 sw_if_index0,
 523              u32 rx_fib_index0,
 524              vlib_node_runtime_t * node,
 525              u32 next0, u32 thread_index, void *d, void *e)
 526 {
 527   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 528   ip4_header_t *inner_ip0 = 0;
 529   void *l4_header = 0;
 530   icmp46_header_t *inner_icmp0;
 531   u8 dont_translate;
 532   u32 new_addr0, old_addr0;
 533   u16 old_id0, new_id0;
 534   ip_csum_t sum0;
 535   u16 checksum0;
 536   u32 next0_tmp;
 537   vlib_main_t *vm = vlib_get_main ();
 538   ip4_address_t addr;
 539   u16 port;
 540   u32 fib_index;
 541   nat_protocol_t proto;
 542
 543   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 544
 545   next0_tmp = sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0,
 546                                         &addr, &port, &fib_index, &proto,
 547                                         d, e, &dont_translate);
 548   if (next0_tmp != ~0)
 549     next0 = next0_tmp;
 550   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
 551     goto out;
 552
 553   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 554     {
 555       sum0 =
 556         ip_incremental_checksum_buffer (vm, b0,
 557                                         (u8 *) icmp0 -
 558                                         (u8 *) vlib_buffer_get_current (b0),
 559                                         ntohs (ip0->length) -
 560                                         ip4_header_bytes (ip0), 0);
 561       checksum0 = ~ip_csum_fold (sum0);
 562       if (checksum0 != 0 && checksum0 != 0xffff)
 563         {
 564           next0 = SNAT_OUT2IN_NEXT_DROP;
 565           goto out;
 566         }
 567     }
 568
 569   old_addr0 = ip0->dst_address.as_u32;
 570   new_addr0 = ip0->dst_address.as_u32 = addr.as_u32;
 571   vnet_buffer (b0)->sw_if_index[VLIB_TX] = fib_index;
 572
 573   sum0 = ip0->checksum;
 574   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 575                          dst_address /* changed member */ );
 576   ip0->checksum = ip_csum_fold (sum0);
 577
 578
 579   if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 580     {
 581       if (icmp0->checksum == 0)
 582         icmp0->checksum = 0xffff;
 583
 584       if (!icmp_type_is_error_message (icmp0->type))
 585         {
 586           new_id0 = port;
 587           if (PREDICT_FALSE (new_id0 != echo0->identifier))
 588             {
 589               old_id0 = echo0->identifier;
 590               new_id0 = port;
 591               echo0->identifier = new_id0;
 592
 593               sum0 = icmp0->checksum;
 594               sum0 =
 595                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 596                                 identifier /* changed member */ );
 597               icmp0->checksum = ip_csum_fold (sum0);
 598             }
 599         }
 600       else
 601         {
 602           inner_ip0 = (ip4_header_t *) (echo0 + 1);
 603           l4_header = ip4_next_header (inner_ip0);
 604
 605           if (!ip4_header_checksum_is_valid (inner_ip0))
 606             {
 607               next0 = SNAT_OUT2IN_NEXT_DROP;
 608               goto out;
 609             }
 610
 611           old_addr0 = inner_ip0->src_address.as_u32;
 612           inner_ip0->src_address = addr;
 613           new_addr0 = inner_ip0->src_address.as_u32;
 614
 615           sum0 = icmp0->checksum;
 616           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 617                                  src_address /* changed member */ );
 618           icmp0->checksum = ip_csum_fold (sum0);
 619
 620           switch (proto)
 621             {
 622             case NAT_PROTOCOL_ICMP:
 623               inner_icmp0 = (icmp46_header_t *) l4_header;
 624               inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 625
 626               old_id0 = inner_echo0->identifier;
 627               new_id0 = port;
 628               inner_echo0->identifier = new_id0;
 629
 630               sum0 = icmp0->checksum;
 631               sum0 =
 632                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 633                                 identifier);
 634               icmp0->checksum = ip_csum_fold (sum0);
 635               break;
 636             case NAT_PROTOCOL_UDP:
 637             case NAT_PROTOCOL_TCP:
 638               old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 639               new_id0 = port;
 640               ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 641
 642               sum0 = icmp0->checksum;
 643               sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 644                                      src_port);
 645               icmp0->checksum = ip_csum_fold (sum0);
 646               break;
 647             default:
 648               ASSERT (0);
 649             }
 650         }
 651     }
 652
 653 out:
 654   return next0;
 655 }
 656 #endif
 657
 658 static inline u32
 659 icmp_out2in_slow_path (snat_main_t * sm,
 660                        vlib_buffer_t * b0,
 661                        ip4_header_t * ip0,
 662                        icmp46_header_t * icmp0,
 663                        u32 sw_if_index0,
 664                        u32 rx_fib_index0,
 665                        vlib_node_runtime_t * node,
 666                        u32 next0, f64 now,
 667                        u32 thread_index, snat_session_t ** p_s0)
 668 {
 669   vlib_main_t *vm = vlib_get_main ();
 670
 671   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 672                        next0, thread_index, p_s0, 0);
 673   snat_session_t *s0 = *p_s0;
 674   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
 675     {
 676       /* Accounting */
 677       nat44_ei_session_update_counters (
 678         s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
 679       /* Per-user LRU list maintenance */
 680       nat44_session_update_lru (sm, s0, thread_index);
 681     }
 682   return next0;
 683 }
 684
 685 static int
 686 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 687                              vlib_buffer_t * b,
 688                              ip4_header_t * ip, u32 rx_fib_index)
 689 {
 690   clib_bihash_kv_8_8_t kv, value;
 691   snat_static_mapping_t *m;
 692   u32 old_addr, new_addr;
 693   ip_csum_t sum;
 694
 695   init_nat_k (&kv, ip->dst_address, 0, 0, 0);
 696   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 697     return 1;
 698
 699   m = pool_elt_at_index (sm->static_mappings, value.value);
 700
 701   old_addr = ip->dst_address.as_u32;
 702   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 703   sum = ip->checksum;
 704   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 705   ip->checksum = ip_csum_fold (sum);
 706
 707   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 708   return 0;
 709 }
 710
 711 VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 712                                  vlib_node_runtime_t * node,
 713                                  vlib_frame_t * frame)
 714 {
 715   u32 n_left_from, *from;
 716   snat_main_t *sm = &snat_main;
 717   f64 now = vlib_time_now (vm);
 718   u32 thread_index = vm->thread_index;
 719   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 720
 721   from = vlib_frame_vector_args (frame);
 722   n_left_from = frame->n_vectors;
 723
 724   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
 725   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 726   vlib_get_buffers (vm, from, b, n_left_from);
 727
 728   while (n_left_from >= 2)
 729     {
 730       vlib_buffer_t *b0, *b1;
 731       u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 732       u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 733       u32 sw_if_index0, sw_if_index1;
 734       ip4_header_t *ip0, *ip1;
 735       ip_csum_t sum0, sum1;
 736       u32 new_addr0, old_addr0;
 737       u16 new_port0, old_port0;
 738       u32 new_addr1, old_addr1;
 739       u16 new_port1, old_port1;
 740       udp_header_t *udp0, *udp1;
 741       tcp_header_t *tcp0, *tcp1;
 742       icmp46_header_t *icmp0, *icmp1;
 743       u32 rx_fib_index0, rx_fib_index1;
 744       u32 proto0, proto1;
 745       snat_session_t *s0 = 0, *s1 = 0;
 746       clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
 747       u8 identity_nat0, identity_nat1;
 748       ip4_address_t sm_addr0, sm_addr1;
 749       u16 sm_port0, sm_port1;
 750       u32 sm_fib_index0, sm_fib_index1;
 751
 752       b0 = *b;
 753       b++;
 754       b1 = *b;
 755       b++;
 756
 757       /* Prefetch next iteration. */
 758       if (PREDICT_TRUE (n_left_from >= 4))
 759         {
 760           vlib_buffer_t *p2, *p3;
 761
 762           p2 = *b;
 763           p3 = *(b + 1);
 764
 765           vlib_prefetch_buffer_header (p2, LOAD);
 766           vlib_prefetch_buffer_header (p3, LOAD);
 767
 768           CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
 769           CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
 770         }
 771
 772       vnet_buffer (b0)->snat.flags = 0;
 773       vnet_buffer (b1)->snat.flags = 0;
 774
 775       ip0 = vlib_buffer_get_current (b0);
 776       udp0 = ip4_next_header (ip0);
 777       tcp0 = (tcp_header_t *) udp0;
 778       icmp0 = (icmp46_header_t *) udp0;
 779
 780       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 781       rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 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 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 791           goto trace0;
 792         }
 793
 794       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 795
 796       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 797         {
 798           if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 799             {
 800               if (!sm->forwarding_enabled)
 801                 {
 802                   b0->error =
 803                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 804                   next0 = SNAT_OUT2IN_NEXT_DROP;
 805                 }
 806             }
 807           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
 808                                          thread_index, sw_if_index0, 1);
 809
 810           goto trace0;
 811         }
 812
 813       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 814         {
 815           next0 = icmp_out2in_slow_path
 816             (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 817              next0, now, thread_index, &s0);
 818           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
 819                                          thread_index, sw_if_index0, 1);
 820           goto trace0;
 821         }
 822
 823       init_nat_k (&kv0, ip0->dst_address,
 824                   vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 825                   proto0);
 826       if (clib_bihash_search_8_8
 827           (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
 828         {
 829           /* Try to match static mapping by external address and port,
 830              destination address and port in packet */
 831           if (snat_static_mapping_match
 832               (sm, ip0->dst_address,
 833                vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 834                proto0, &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
 835                0, &identity_nat0, 0))
 836             {
 837               /*
 838                * Send DHCP packets to the ipv4 stack, or we won't
 839                * be able to use dhcp client on the outside interface
 840                */
 841               if (PREDICT_FALSE
 842                   (proto0 == NAT_PROTOCOL_UDP
 843                    && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
 844                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
 845                 {
 846                   vnet_feature_next (&next0, b0);
 847                   goto trace0;
 848                 }
 849
 850               if (!sm->forwarding_enabled)
 851                 {
 852                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 853                   next0 = SNAT_OUT2IN_NEXT_DROP;
 854                 }
 855               goto trace0;
 856             }
 857
 858           if (PREDICT_FALSE (identity_nat0))
 859             goto trace0;
 860
 861           /* Create session initiated by host from external network */
 862           s0 = create_session_for_static_mapping (sm, b0,
 863                                                   sm_addr0, sm_port0,
 864                                                   sm_fib_index0,
 865                                                   ip0->dst_address,
 866                                                   vnet_buffer (b0)->ip.
 867                                                   reass.l4_dst_port,
 868                                                   rx_fib_index0, proto0, node,
 869                                                   thread_index, now);
 870           if (!s0)
 871             {
 872               next0 = SNAT_OUT2IN_NEXT_DROP;
 873               goto trace0;
 874             }
 875         }
 876       else
 877         s0 = pool_elt_at_index (tsm->sessions, value0.value);
 878
 879       old_addr0 = ip0->dst_address.as_u32;
 880       ip0->dst_address = s0->in2out.addr;
 881       new_addr0 = ip0->dst_address.as_u32;
 882       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 883
 884       sum0 = ip0->checksum;
 885       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 886                              ip4_header_t, dst_address /* changed member */ );
 887       ip0->checksum = ip_csum_fold (sum0);
 888
 889       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 890         {
 891           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 892             {
 893               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 894               new_port0 = udp0->dst_port = s0->in2out.port;
 895               sum0 = tcp0->checksum;
 896               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 897                                      ip4_header_t,
 898                                      dst_address /* changed member */ );
 899
 900               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 901                                      ip4_header_t /* cheat */ ,
 902                                      length /* changed member */ );
 903               tcp0->checksum = ip_csum_fold (sum0);
 904             }
 905           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
 906                                          thread_index, sw_if_index0, 1);
 907         }
 908       else
 909         {
 910           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 911             {
 912               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 913               new_port0 = udp0->dst_port = s0->in2out.port;
 914               if (PREDICT_FALSE (udp0->checksum))
 915                 {
 916                   sum0 = udp0->checksum;
 917                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
 918                     );
 919                   sum0 =
 920                     ip_csum_update (sum0, old_port0, new_port0,
 921                                     ip4_header_t /* cheat */ ,
 922                                     length /* changed member */ );
 923                   udp0->checksum = ip_csum_fold (sum0);
 924                 }
 925             }
 926           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
 927                                          thread_index, sw_if_index0, 1);
 928         }
 929
 930       /* Accounting */
 931       nat44_ei_session_update_counters (
 932         s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
 933       /* Per-user LRU list maintenance */
 934       nat44_session_update_lru (sm, s0, thread_index);
 935     trace0:
 936
 937       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 938                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 939         {
 940           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
 941           t->sw_if_index = sw_if_index0;
 942           t->next_index = next0;
 943           t->session_index = ~0;
 944           if (s0)
 945             t->session_index =
 946               s0 - sm->per_thread_data[thread_index].sessions;
 947         }
 948
 949       if (next0 == SNAT_OUT2IN_NEXT_DROP)
 950         {
 951           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
 952                                          thread_index, sw_if_index0, 1);
 953         }
 954
 955
 956       ip1 = vlib_buffer_get_current (b1);
 957       udp1 = ip4_next_header (ip1);
 958       tcp1 = (tcp_header_t *) udp1;
 959       icmp1 = (icmp46_header_t *) udp1;
 960
 961       sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 962       rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 963                                sw_if_index1);
 964
 965       if (PREDICT_FALSE (ip1->ttl == 1))
 966         {
 967           vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 968           icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 969                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 970                                        0);
 971           next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 972           goto trace1;
 973         }
 974
 975       proto1 = ip_proto_to_nat_proto (ip1->protocol);
 976
 977       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
 978         {
 979           if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
 980             {
 981               if (!sm->forwarding_enabled)
 982                 {
 983                   b1->error =
 984                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 985                   next1 = SNAT_OUT2IN_NEXT_DROP;
 986                 }
 987             }
 988           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
 989                                          thread_index, sw_if_index1, 1);
 990           goto trace1;
 991         }
 992
 993       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 994         {
 995           next1 = icmp_out2in_slow_path
 996             (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
 997              next1, now, thread_index, &s1);
 998           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
 999                                          thread_index, sw_if_index1, 1);
1000           goto trace1;
1001         }
1002
1003       init_nat_k (&kv1, ip1->dst_address,
1004                   vnet_buffer (b1)->ip.reass.l4_dst_port, rx_fib_index1,
1005                   proto1);
1006
1007       if (clib_bihash_search_8_8
1008           (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
1009         {
1010           /* Try to match static mapping by external address and port,
1011              destination address and port in packet */
1012           if (snat_static_mapping_match
1013               (sm, ip1->dst_address,
1014                vnet_buffer (b1)->ip.reass.l4_dst_port, proto1,
1015                rx_fib_index1, &sm_addr1, &sm_port1, &sm_fib_index1, 1, 0,
1016                0, 0, 0, &identity_nat1, 0))
1017             {
1018               /*
1019                * Send DHCP packets to the ipv4 stack, or we won't
1020                * be able to use dhcp client on the outside interface
1021                */
1022               if (PREDICT_FALSE
1023                   (proto1 == NAT_PROTOCOL_UDP
1024                    && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
1025                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
1026                 {
1027                   vnet_feature_next (&next1, b1);
1028                   goto trace1;
1029                 }
1030
1031               if (!sm->forwarding_enabled)
1032                 {
1033                   b1->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1034                   next1 = SNAT_OUT2IN_NEXT_DROP;
1035                 }
1036               goto trace1;
1037             }
1038
1039           if (PREDICT_FALSE (identity_nat1))
1040             goto trace1;
1041
1042           /* Create session initiated by host from external network */
1043           s1 =
1044             create_session_for_static_mapping (sm, b1, sm_addr1, sm_port1,
1045                                                sm_fib_index1,
1046                                                ip1->dst_address,
1047                                                vnet_buffer (b1)->ip.
1048                                                reass.l4_dst_port,
1049                                                rx_fib_index1, proto1, node,
1050                                                thread_index, now);
1051           if (!s1)
1052             {
1053               next1 = SNAT_OUT2IN_NEXT_DROP;
1054               goto trace1;
1055             }
1056         }
1057       else
1058         s1 =
1059           pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1060                              value1.value);
1061
1062       old_addr1 = ip1->dst_address.as_u32;
1063       ip1->dst_address = s1->in2out.addr;
1064       new_addr1 = ip1->dst_address.as_u32;
1065       vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1066
1067       sum1 = ip1->checksum;
1068       sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1069                              ip4_header_t, dst_address /* changed member */ );
1070       ip1->checksum = ip_csum_fold (sum1);
1071
1072       if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
1073         {
1074           if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1075             {
1076               old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1077               new_port1 = udp1->dst_port = s1->in2out.port;
1078
1079               sum1 = tcp1->checksum;
1080               sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1081                                      ip4_header_t,
1082                                      dst_address /* changed member */ );
1083
1084               sum1 = ip_csum_update (sum1, old_port1, new_port1,
1085                                      ip4_header_t /* cheat */ ,
1086                                      length /* changed member */ );
1087               tcp1->checksum = ip_csum_fold (sum1);
1088             }
1089           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
1090                                          thread_index, sw_if_index1, 1);
1091         }
1092       else
1093         {
1094           if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1095             {
1096               old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1097               new_port1 = udp1->dst_port = s1->in2out.port;
1098               if (PREDICT_FALSE (udp1->checksum))
1099                 {
1100
1101                   sum1 = udp1->checksum;
1102                   sum1 =
1103                     ip_csum_update (sum1, old_addr1, new_addr1,
1104                                     ip4_header_t,
1105                                     dst_address /* changed member */ );
1106                   sum1 =
1107                     ip_csum_update (sum1, old_port1, new_port1,
1108                                     ip4_header_t /* cheat */ ,
1109                                     length /* changed member */ );
1110                   udp1->checksum = ip_csum_fold (sum1);
1111                 }
1112             }
1113           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
1114                                          thread_index, sw_if_index1, 1);
1115         }
1116
1117       /* Accounting */
1118       nat44_ei_session_update_counters (
1119         s1, now, vlib_buffer_length_in_chain (vm, b1), thread_index);
1120       /* Per-user LRU list maintenance */
1121       nat44_session_update_lru (sm, s1, thread_index);
1122     trace1:
1123
1124       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1125                          && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1126         {
1127           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b1, sizeof (*t));
1128           t->sw_if_index = sw_if_index1;
1129           t->next_index = next1;
1130           t->session_index = ~0;
1131           if (s1)
1132             t->session_index =
1133               s1 - sm->per_thread_data[thread_index].sessions;
1134         }
1135
1136       if (next1 == SNAT_OUT2IN_NEXT_DROP)
1137         {
1138           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
1139                                          thread_index, sw_if_index1, 1);
1140         }
1141
1142       n_left_from -= 2;
1143       next[0] = next0;
1144       next[1] = next1;
1145       next += 2;
1146     }
1147
1148   while (n_left_from > 0)
1149     {
1150       vlib_buffer_t *b0;
1151       u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1152       u32 sw_if_index0;
1153       ip4_header_t *ip0;
1154       ip_csum_t sum0;
1155       u32 new_addr0, old_addr0;
1156       u16 new_port0, old_port0;
1157       udp_header_t *udp0;
1158       tcp_header_t *tcp0;
1159       icmp46_header_t *icmp0;
1160       u32 rx_fib_index0;
1161       u32 proto0;
1162       snat_session_t *s0 = 0;
1163       clib_bihash_kv_8_8_t kv0, value0;
1164       u8 identity_nat0;
1165       ip4_address_t sm_addr0;
1166       u16 sm_port0;
1167       u32 sm_fib_index0;
1168
1169       b0 = *b;
1170       ++b;
1171
1172       vnet_buffer (b0)->snat.flags = 0;
1173
1174       ip0 = vlib_buffer_get_current (b0);
1175       udp0 = ip4_next_header (ip0);
1176       tcp0 = (tcp_header_t *) udp0;
1177       icmp0 = (icmp46_header_t *) udp0;
1178
1179       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1180       rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1181                                sw_if_index0);
1182
1183       proto0 = ip_proto_to_nat_proto (ip0->protocol);
1184
1185       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1186         {
1187           if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1188             {
1189               if (!sm->forwarding_enabled)
1190                 {
1191                   b0->error =
1192                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1193                   next0 = SNAT_OUT2IN_NEXT_DROP;
1194                 }
1195             }
1196           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
1197                                          thread_index, sw_if_index0, 1);
1198           goto trace00;
1199         }
1200
1201       if (PREDICT_FALSE (ip0->ttl == 1))
1202         {
1203           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1204           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1205                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
1206                                        0);
1207           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1208           goto trace00;
1209         }
1210
1211       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1212         {
1213           next0 = icmp_out2in_slow_path
1214             (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1215              next0, now, thread_index, &s0);
1216           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
1217                                          thread_index, sw_if_index0, 1);
1218           goto trace00;
1219         }
1220
1221       init_nat_k (&kv0, ip0->dst_address,
1222                   vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
1223                   proto0);
1224
1225       if (clib_bihash_search_8_8
1226           (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
1227         {
1228           /* Try to match static mapping by external address and port,
1229              destination address and port in packet */
1230           if (snat_static_mapping_match
1231               (sm, ip0->dst_address,
1232                vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
1233                proto0, &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
1234                0, &identity_nat0, 0))
1235             {
1236               /*
1237                * Send DHCP packets to the ipv4 stack, or we won't
1238                * be able to use dhcp client on the outside interface
1239                */
1240               if (PREDICT_FALSE
1241                   (proto0 == NAT_PROTOCOL_UDP
1242                    && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
1243                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
1244                 {
1245                   vnet_feature_next (&next0, b0);
1246                   goto trace00;
1247                 }
1248
1249               if (!sm->forwarding_enabled)
1250                 {
1251                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1252                   next0 = SNAT_OUT2IN_NEXT_DROP;
1253                 }
1254               goto trace00;
1255             }
1256
1257           if (PREDICT_FALSE (identity_nat0))
1258             goto trace00;
1259
1260           /* Create session initiated by host from external network */
1261           s0 = create_session_for_static_mapping (sm, b0,
1262                                                   sm_addr0, sm_port0,
1263                                                   sm_fib_index0,
1264                                                   ip0->dst_address,
1265                                                   vnet_buffer (b0)->ip.
1266                                                   reass.l4_dst_port,
1267                                                   rx_fib_index0, proto0, node,
1268                                                   thread_index, now);
1269           if (!s0)
1270             {
1271               next0 = SNAT_OUT2IN_NEXT_DROP;
1272               goto trace00;
1273             }
1274         }
1275       else
1276         s0 =
1277           pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1278                              value0.value);
1279
1280       old_addr0 = ip0->dst_address.as_u32;
1281       ip0->dst_address = s0->in2out.addr;
1282       new_addr0 = ip0->dst_address.as_u32;
1283       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1284
1285       sum0 = ip0->checksum;
1286       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1287                              ip4_header_t, dst_address /* changed member */ );
1288       ip0->checksum = ip_csum_fold (sum0);
1289
1290       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1291         {
1292           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1293             {
1294               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1295               new_port0 = udp0->dst_port = s0->in2out.port;
1296
1297               sum0 = tcp0->checksum;
1298               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1299                                      ip4_header_t,
1300                                      dst_address /* changed member */ );
1301
1302               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1303                                      ip4_header_t /* cheat */ ,
1304                                      length /* changed member */ );
1305               tcp0->checksum = ip_csum_fold (sum0);
1306             }
1307           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
1308                                          thread_index, sw_if_index0, 1);
1309         }
1310       else
1311         {
1312           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1313             {
1314               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1315               new_port0 = udp0->dst_port = s0->in2out.port;
1316               if (PREDICT_FALSE (udp0->checksum))
1317                 {
1318                   sum0 = udp0->checksum;
1319                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
1320                     );
1321                   sum0 =
1322                     ip_csum_update (sum0, old_port0, new_port0,
1323                                     ip4_header_t /* cheat */ ,
1324                                     length /* changed member */ );
1325                   udp0->checksum = ip_csum_fold (sum0);
1326                 }
1327             }
1328           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
1329                                          thread_index, sw_if_index0, 1);
1330         }
1331
1332       /* Accounting */
1333       nat44_ei_session_update_counters (
1334         s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
1335       /* Per-user LRU list maintenance */
1336       nat44_session_update_lru (sm, s0, thread_index);
1337     trace00:
1338
1339       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1340                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1341         {
1342           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
1343           t->sw_if_index = sw_if_index0;
1344           t->next_index = next0;
1345           t->session_index = ~0;
1346           if (s0)
1347             t->session_index =
1348               s0 - sm->per_thread_data[thread_index].sessions;
1349         }
1350
1351       if (next0 == SNAT_OUT2IN_NEXT_DROP)
1352         {
1353           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
1354                                          thread_index, sw_if_index0, 1);
1355         }
1356
1357       n_left_from--;
1358       next[0] = next0;
1359       next++;
1360     }
1361
1362   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
1363                                frame->n_vectors);
1364
1365   return frame->n_vectors;
1366 }
1367
1368 /* *INDENT-OFF* */
1369 VLIB_REGISTER_NODE (snat_out2in_node) = {
1370   .name = "nat44-out2in",
1371   .vector_size = sizeof (u32),
1372   .format_trace = format_snat_out2in_trace,
1373   .type = VLIB_NODE_TYPE_INTERNAL,
1374
1375   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1376   .error_strings = snat_out2in_error_strings,
1377
1378   .runtime_data_bytes = sizeof (snat_runtime_t),
1379
1380   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1381
1382   /* edit / add dispositions here */
1383   .next_nodes = {
1384     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1385     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1386     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1387   },
1388 };
1389 /* *INDENT-ON* */
1390
1391 VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
1392                                       vlib_node_runtime_t * node,
1393                                       vlib_frame_t * frame)
1394 {
1395   u32 n_left_from, *from;
1396   snat_main_t *sm = &snat_main;
1397
1398   from = vlib_frame_vector_args (frame);
1399   n_left_from = frame->n_vectors;
1400
1401   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
1402   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
1403   vlib_get_buffers (vm, from, b, n_left_from);
1404   while (n_left_from > 0)
1405     {
1406       vlib_buffer_t *b0;
1407       u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1408       u32 sw_if_index0;
1409       ip4_header_t *ip0;
1410       ip_csum_t sum0;
1411       u32 new_addr0, old_addr0;
1412       u16 new_port0, old_port0;
1413       udp_header_t *udp0;
1414       tcp_header_t *tcp0;
1415       icmp46_header_t *icmp0;
1416       u32 proto0;
1417       u32 rx_fib_index0;
1418       ip4_address_t sm_addr0;
1419       u16 sm_port0;
1420       u32 sm_fib_index0;
1421
1422       b0 = *b;
1423       b++;
1424
1425       ip0 = vlib_buffer_get_current (b0);
1426       udp0 = ip4_next_header (ip0);
1427       tcp0 = (tcp_header_t *) udp0;
1428       icmp0 = (icmp46_header_t *) udp0;
1429
1430       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1431       rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1432
1433       vnet_feature_next (&next0, b0);
1434
1435       if (PREDICT_FALSE (ip0->ttl == 1))
1436         {
1437           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1438           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1439                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
1440                                        0);
1441           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1442           goto trace00;
1443         }
1444
1445       proto0 = ip_proto_to_nat_proto (ip0->protocol);
1446
1447       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1448         goto trace00;
1449
1450       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1451         {
1452           next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1453                                rx_fib_index0, node, next0, ~0, 0, 0);
1454           goto trace00;
1455         }
1456
1457       if (snat_static_mapping_match
1458           (sm, ip0->dst_address, udp0->dst_port, rx_fib_index0, proto0,
1459            &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0, 0, 0, 0))
1460         {
1461           b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1462           goto trace00;
1463         }
1464
1465       new_addr0 = sm_addr0.as_u32;
1466       new_port0 = sm_port0;
1467       vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm_fib_index0;
1468       old_addr0 = ip0->dst_address.as_u32;
1469       ip0->dst_address.as_u32 = new_addr0;
1470
1471       sum0 = ip0->checksum;
1472       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1473                              ip4_header_t, dst_address /* changed member */ );
1474       ip0->checksum = ip_csum_fold (sum0);
1475
1476       if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1477         {
1478           old_port0 = udp0->dst_port;
1479           udp0->dst_port = new_port0;
1480
1481           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1482             {
1483               sum0 = tcp0->checksum;
1484               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1485                                      ip4_header_t,
1486                                      dst_address /* changed member */ );
1487               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1488                                      ip4_header_t /* cheat */ ,
1489                                      length /* changed member */ );
1490               tcp0->checksum = ip_csum_fold (sum0);
1491             }
1492           else if (udp0->checksum)
1493             {
1494               sum0 = udp0->checksum;
1495               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1496                                      ip4_header_t,
1497                                      dst_address /* changed member */ );
1498               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1499                                      ip4_header_t /* cheat */ ,
1500                                      length /* changed member */ );
1501               udp0->checksum = ip_csum_fold (sum0);
1502             }
1503         }
1504       else
1505         {
1506           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1507             {
1508               sum0 = tcp0->checksum;
1509               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1510                                      ip4_header_t,
1511                                      dst_address /* changed member */ );
1512               tcp0->checksum = ip_csum_fold (sum0);
1513             }
1514           else if (udp0->checksum)
1515             {
1516               sum0 = udp0->checksum;
1517               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1518                                      ip4_header_t,
1519                                      dst_address /* changed member */ );
1520               udp0->checksum = ip_csum_fold (sum0);
1521             }
1522         }
1523
1524     trace00:
1525
1526       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1527                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1528         {
1529           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
1530           t->sw_if_index = sw_if_index0;
1531           t->next_index = next0;
1532         }
1533
1534       if (next0 == SNAT_OUT2IN_NEXT_DROP)
1535         {
1536           vlib_increment_simple_counter (&sm->counters.fastpath.out2in.drops,
1537                                          vm->thread_index, sw_if_index0, 1);
1538         }
1539
1540       n_left_from--;
1541       next[0] = next0;
1542       next++;
1543     }
1544
1545   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
1546                                frame->n_vectors);
1547
1548   return frame->n_vectors;
1549 }
1550
1551 /* *INDENT-OFF* */
1552 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1553   .name = "nat44-out2in-fast",
1554   .vector_size = sizeof (u32),
1555   .format_trace = format_snat_out2in_fast_trace,
1556   .type = VLIB_NODE_TYPE_INTERNAL,
1557
1558   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1559   .error_strings = snat_out2in_error_strings,
1560
1561   .runtime_data_bytes = sizeof (snat_runtime_t),
1562
1563   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1564
1565   /* edit / add dispositions here */
1566   .next_nodes = {
1567     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1568     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1569     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1570   },
1571 };
1572 /* *INDENT-ON* */
1573
1574 /*
1575  * fd.io coding-style-patch-verification: ON
1576  *
1577  * Local Variables:
1578  * eval: (c-set-style "gnu")
1579  * End:
1580  */