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 #include <nat/nat44-ei/nat44_ei.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 (&sm->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_ei_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, thread_index,
 226                    s - sm->per_thread_data[thread_index].sessions);
 227   if (clib_bihash_add_or_overwrite_stale_8_8 (
 228         &sm->in2out, &kv0, nat44_i2o_is_idle_session_cb, &ctx0))
 229     nat_elog_notice ("in2out key add failed");
 230
 231   init_nat_o2i_kv (&kv0, s, thread_index,
 232                    s - sm->per_thread_data[thread_index].sessions);
 233   if (clib_bihash_add_or_overwrite_stale_8_8 (
 234         &sm->out2in, &kv0, 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 (&sm->out2in, &kv0, &value0))
 355     {
 356       /* Try to match static mapping by external address and port,
 357          destination address and port in packet */
 358       if (nat44_ei_static_mapping_match (
 359             *addr, *port, *fib_index, *proto, &mapping_addr, &mapping_port,
 360             &mapping_fib_index, 1, &is_addr_only, &identity_nat))
 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,
 427                               nat_value_get_session_index (&value0));
 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 (nat44_ei_static_mapping_match (addr, port, rx_fib_index0, *proto,
 486                                      mapping_addr, mapping_port,
 487                                      mapping_fib_index, 1, &is_addr_only, 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_ei_session_update_counters (
 679         s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
 680       /* Per-user LRU list maintenance */
 681       nat44_session_update_lru (sm, s0, thread_index);
 682     }
 683   return next0;
 684 }
 685
 686 static int
 687 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 688                              vlib_buffer_t * b,
 689                              ip4_header_t * ip, u32 rx_fib_index)
 690 {
 691   clib_bihash_kv_8_8_t kv, value;
 692   snat_static_mapping_t *m;
 693   u32 old_addr, new_addr;
 694   ip_csum_t sum;
 695
 696   init_nat_k (&kv, ip->dst_address, 0, 0, 0);
 697   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 698     return 1;
 699
 700   m = pool_elt_at_index (sm->static_mappings, value.value);
 701
 702   old_addr = ip->dst_address.as_u32;
 703   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 704   sum = ip->checksum;
 705   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 706   ip->checksum = ip_csum_fold (sum);
 707
 708   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 709   return 0;
 710 }
 711
 712 VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 713                                  vlib_node_runtime_t * node,
 714                                  vlib_frame_t * frame)
 715 {
 716   u32 n_left_from, *from;
 717   snat_main_t *sm = &snat_main;
 718   f64 now = vlib_time_now (vm);
 719   u32 thread_index = vm->thread_index;
 720   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 721
 722   from = vlib_frame_vector_args (frame);
 723   n_left_from = frame->n_vectors;
 724
 725   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
 726   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 727   vlib_get_buffers (vm, from, b, n_left_from);
 728
 729   while (n_left_from >= 2)
 730     {
 731       vlib_buffer_t *b0, *b1;
 732       u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 733       u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 734       u32 sw_if_index0, sw_if_index1;
 735       ip4_header_t *ip0, *ip1;
 736       ip_csum_t sum0, sum1;
 737       u32 new_addr0, old_addr0;
 738       u16 new_port0, old_port0;
 739       u32 new_addr1, old_addr1;
 740       u16 new_port1, old_port1;
 741       udp_header_t *udp0, *udp1;
 742       tcp_header_t *tcp0, *tcp1;
 743       icmp46_header_t *icmp0, *icmp1;
 744       u32 rx_fib_index0, rx_fib_index1;
 745       u32 proto0, proto1;
 746       snat_session_t *s0 = 0, *s1 = 0;
 747       clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
 748       u8 identity_nat0, identity_nat1;
 749       ip4_address_t sm_addr0, sm_addr1;
 750       u16 sm_port0, sm_port1;
 751       u32 sm_fib_index0, sm_fib_index1;
 752
 753       b0 = *b;
 754       b++;
 755       b1 = *b;
 756       b++;
 757
 758       /* Prefetch next iteration. */
 759       if (PREDICT_TRUE (n_left_from >= 4))
 760         {
 761           vlib_buffer_t *p2, *p3;
 762
 763           p2 = *b;
 764           p3 = *(b + 1);
 765
 766           vlib_prefetch_buffer_header (p2, LOAD);
 767           vlib_prefetch_buffer_header (p3, LOAD);
 768
 769           CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
 770           CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
 771         }
 772
 773       vnet_buffer (b0)->snat.flags = 0;
 774       vnet_buffer (b1)->snat.flags = 0;
 775
 776       ip0 = vlib_buffer_get_current (b0);
 777       udp0 = ip4_next_header (ip0);
 778       tcp0 = (tcp_header_t *) udp0;
 779       icmp0 = (icmp46_header_t *) udp0;
 780
 781       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 782       rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 783                                sw_if_index0);
 784
 785       if (PREDICT_FALSE (ip0->ttl == 1))
 786         {
 787           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 788           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 789                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 790                                        0);
 791           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 792           goto trace0;
 793         }
 794
 795       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 796
 797       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 798         {
 799           if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 800             {
 801               if (!sm->forwarding_enabled)
 802                 {
 803                   b0->error =
 804                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 805                   next0 = SNAT_OUT2IN_NEXT_DROP;
 806                 }
 807             }
 808           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
 809                                          thread_index, sw_if_index0, 1);
 810
 811           goto trace0;
 812         }
 813
 814       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 815         {
 816           next0 = icmp_out2in_slow_path
 817             (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 818              next0, now, thread_index, &s0);
 819           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
 820                                          thread_index, sw_if_index0, 1);
 821           goto trace0;
 822         }
 823
 824       init_nat_k (&kv0, ip0->dst_address,
 825                   vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 826                   proto0);
 827       if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
 828         {
 829           /* Try to match static mapping by external address and port,
 830              destination address and port in packet */
 831           if (nat44_ei_static_mapping_match (
 832                 ip0->dst_address, vnet_buffer (b0)->ip.reass.l4_dst_port,
 833                 rx_fib_index0, proto0, &sm_addr0, &sm_port0, &sm_fib_index0, 1,
 834                 0, &identity_nat0))
 835             {
 836               /*
 837                * Send DHCP packets to the ipv4 stack, or we won't
 838                * be able to use dhcp client on the outside interface
 839                */
 840               if (PREDICT_FALSE
 841                   (proto0 == NAT_PROTOCOL_UDP
 842                    && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
 843                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
 844                 {
 845                   vnet_feature_next (&next0, b0);
 846                   goto trace0;
 847                 }
 848
 849               if (!sm->forwarding_enabled)
 850                 {
 851                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 852                   next0 = SNAT_OUT2IN_NEXT_DROP;
 853                 }
 854               goto trace0;
 855             }
 856
 857           if (PREDICT_FALSE (identity_nat0))
 858             goto trace0;
 859
 860           /* Create session initiated by host from external network */
 861           s0 = create_session_for_static_mapping (sm, b0,
 862                                                   sm_addr0, sm_port0,
 863                                                   sm_fib_index0,
 864                                                   ip0->dst_address,
 865                                                   vnet_buffer (b0)->ip.
 866                                                   reass.l4_dst_port,
 867                                                   rx_fib_index0, proto0, node,
 868                                                   thread_index, now);
 869           if (!s0)
 870             {
 871               next0 = SNAT_OUT2IN_NEXT_DROP;
 872               goto trace0;
 873             }
 874         }
 875       else
 876         s0 = pool_elt_at_index (tsm->sessions,
 877                                 nat_value_get_session_index (&value0));
 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       if (clib_bihash_search_8_8 (&sm->out2in, &kv1, &value1))
1007         {
1008           /* Try to match static mapping by external address and port,
1009              destination address and port in packet */
1010           if (nat44_ei_static_mapping_match (
1011                 ip1->dst_address, vnet_buffer (b1)->ip.reass.l4_dst_port,
1012                 rx_fib_index1, proto1, &sm_addr1, &sm_port1, &sm_fib_index1, 1,
1013                 0, &identity_nat1))
1014             {
1015               /*
1016                * Send DHCP packets to the ipv4 stack, or we won't
1017                * be able to use dhcp client on the outside interface
1018                */
1019               if (PREDICT_FALSE
1020                   (proto1 == NAT_PROTOCOL_UDP
1021                    && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
1022                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
1023                 {
1024                   vnet_feature_next (&next1, b1);
1025                   goto trace1;
1026                 }
1027
1028               if (!sm->forwarding_enabled)
1029                 {
1030                   b1->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1031                   next1 = SNAT_OUT2IN_NEXT_DROP;
1032                 }
1033               goto trace1;
1034             }
1035
1036           if (PREDICT_FALSE (identity_nat1))
1037             goto trace1;
1038
1039           /* Create session initiated by host from external network */
1040           s1 =
1041             create_session_for_static_mapping (sm, b1, sm_addr1, sm_port1,
1042                                                sm_fib_index1,
1043                                                ip1->dst_address,
1044                                                vnet_buffer (b1)->ip.
1045                                                reass.l4_dst_port,
1046                                                rx_fib_index1, proto1, node,
1047                                                thread_index, now);
1048           if (!s1)
1049             {
1050               next1 = SNAT_OUT2IN_NEXT_DROP;
1051               goto trace1;
1052             }
1053         }
1054       else
1055         s1 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1056                                 nat_value_get_session_index (&value1));
1057
1058       old_addr1 = ip1->dst_address.as_u32;
1059       ip1->dst_address = s1->in2out.addr;
1060       new_addr1 = ip1->dst_address.as_u32;
1061       vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1062
1063       sum1 = ip1->checksum;
1064       sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1065                              ip4_header_t, dst_address /* changed member */ );
1066       ip1->checksum = ip_csum_fold (sum1);
1067
1068       if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
1069         {
1070           if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1071             {
1072               old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1073               new_port1 = udp1->dst_port = s1->in2out.port;
1074
1075               sum1 = tcp1->checksum;
1076               sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1077                                      ip4_header_t,
1078                                      dst_address /* changed member */ );
1079
1080               sum1 = ip_csum_update (sum1, old_port1, new_port1,
1081                                      ip4_header_t /* cheat */ ,
1082                                      length /* changed member */ );
1083               tcp1->checksum = ip_csum_fold (sum1);
1084             }
1085           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
1086                                          thread_index, sw_if_index1, 1);
1087         }
1088       else
1089         {
1090           if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1091             {
1092               old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1093               new_port1 = udp1->dst_port = s1->in2out.port;
1094               if (PREDICT_FALSE (udp1->checksum))
1095                 {
1096
1097                   sum1 = udp1->checksum;
1098                   sum1 =
1099                     ip_csum_update (sum1, old_addr1, new_addr1,
1100                                     ip4_header_t,
1101                                     dst_address /* changed member */ );
1102                   sum1 =
1103                     ip_csum_update (sum1, old_port1, new_port1,
1104                                     ip4_header_t /* cheat */ ,
1105                                     length /* changed member */ );
1106                   udp1->checksum = ip_csum_fold (sum1);
1107                 }
1108             }
1109           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
1110                                          thread_index, sw_if_index1, 1);
1111         }
1112
1113       /* Accounting */
1114       nat44_ei_session_update_counters (
1115         s1, now, vlib_buffer_length_in_chain (vm, b1), thread_index);
1116       /* Per-user LRU list maintenance */
1117       nat44_session_update_lru (sm, s1, thread_index);
1118     trace1:
1119
1120       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1121                          && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1122         {
1123           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b1, sizeof (*t));
1124           t->sw_if_index = sw_if_index1;
1125           t->next_index = next1;
1126           t->session_index = ~0;
1127           if (s1)
1128             t->session_index =
1129               s1 - sm->per_thread_data[thread_index].sessions;
1130         }
1131
1132       if (next1 == SNAT_OUT2IN_NEXT_DROP)
1133         {
1134           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
1135                                          thread_index, sw_if_index1, 1);
1136         }
1137
1138       n_left_from -= 2;
1139       next[0] = next0;
1140       next[1] = next1;
1141       next += 2;
1142     }
1143
1144   while (n_left_from > 0)
1145     {
1146       vlib_buffer_t *b0;
1147       u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1148       u32 sw_if_index0;
1149       ip4_header_t *ip0;
1150       ip_csum_t sum0;
1151       u32 new_addr0, old_addr0;
1152       u16 new_port0, old_port0;
1153       udp_header_t *udp0;
1154       tcp_header_t *tcp0;
1155       icmp46_header_t *icmp0;
1156       u32 rx_fib_index0;
1157       u32 proto0;
1158       snat_session_t *s0 = 0;
1159       clib_bihash_kv_8_8_t kv0, value0;
1160       u8 identity_nat0;
1161       ip4_address_t sm_addr0;
1162       u16 sm_port0;
1163       u32 sm_fib_index0;
1164
1165       b0 = *b;
1166       ++b;
1167
1168       vnet_buffer (b0)->snat.flags = 0;
1169
1170       ip0 = vlib_buffer_get_current (b0);
1171       udp0 = ip4_next_header (ip0);
1172       tcp0 = (tcp_header_t *) udp0;
1173       icmp0 = (icmp46_header_t *) udp0;
1174
1175       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1176       rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1177                                sw_if_index0);
1178
1179       proto0 = ip_proto_to_nat_proto (ip0->protocol);
1180
1181       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1182         {
1183           if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1184             {
1185               if (!sm->forwarding_enabled)
1186                 {
1187                   b0->error =
1188                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1189                   next0 = SNAT_OUT2IN_NEXT_DROP;
1190                 }
1191             }
1192           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
1193                                          thread_index, sw_if_index0, 1);
1194           goto trace00;
1195         }
1196
1197       if (PREDICT_FALSE (ip0->ttl == 1))
1198         {
1199           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1200           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1201                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
1202                                        0);
1203           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1204           goto trace00;
1205         }
1206
1207       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1208         {
1209           next0 = icmp_out2in_slow_path
1210             (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1211              next0, now, thread_index, &s0);
1212           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
1213                                          thread_index, sw_if_index0, 1);
1214           goto trace00;
1215         }
1216
1217       init_nat_k (&kv0, ip0->dst_address,
1218                   vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
1219                   proto0);
1220
1221       if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
1222         {
1223           /* Try to match static mapping by external address and port,
1224              destination address and port in packet */
1225           if (nat44_ei_static_mapping_match (
1226                 ip0->dst_address, vnet_buffer (b0)->ip.reass.l4_dst_port,
1227                 rx_fib_index0, proto0, &sm_addr0, &sm_port0, &sm_fib_index0, 1,
1228                 0, &identity_nat0))
1229             {
1230               /*
1231                * Send DHCP packets to the ipv4 stack, or we won't
1232                * be able to use dhcp client on the outside interface
1233                */
1234               if (PREDICT_FALSE
1235                   (proto0 == NAT_PROTOCOL_UDP
1236                    && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
1237                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
1238                 {
1239                   vnet_feature_next (&next0, b0);
1240                   goto trace00;
1241                 }
1242
1243               if (!sm->forwarding_enabled)
1244                 {
1245                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1246                   next0 = SNAT_OUT2IN_NEXT_DROP;
1247                 }
1248               goto trace00;
1249             }
1250
1251           if (PREDICT_FALSE (identity_nat0))
1252             goto trace00;
1253
1254           /* Create session initiated by host from external network */
1255           s0 = create_session_for_static_mapping (sm, b0,
1256                                                   sm_addr0, sm_port0,
1257                                                   sm_fib_index0,
1258                                                   ip0->dst_address,
1259                                                   vnet_buffer (b0)->ip.
1260                                                   reass.l4_dst_port,
1261                                                   rx_fib_index0, proto0, node,
1262                                                   thread_index, now);
1263           if (!s0)
1264             {
1265               next0 = SNAT_OUT2IN_NEXT_DROP;
1266               goto trace00;
1267             }
1268         }
1269       else
1270         s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1271                                 nat_value_get_session_index (&value0));
1272
1273       old_addr0 = ip0->dst_address.as_u32;
1274       ip0->dst_address = s0->in2out.addr;
1275       new_addr0 = ip0->dst_address.as_u32;
1276       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1277
1278       sum0 = ip0->checksum;
1279       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1280                              ip4_header_t, dst_address /* changed member */ );
1281       ip0->checksum = ip_csum_fold (sum0);
1282
1283       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1284         {
1285           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1286             {
1287               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1288               new_port0 = udp0->dst_port = s0->in2out.port;
1289
1290               sum0 = tcp0->checksum;
1291               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1292                                      ip4_header_t,
1293                                      dst_address /* changed member */ );
1294
1295               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1296                                      ip4_header_t /* cheat */ ,
1297                                      length /* changed member */ );
1298               tcp0->checksum = ip_csum_fold (sum0);
1299             }
1300           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
1301                                          thread_index, sw_if_index0, 1);
1302         }
1303       else
1304         {
1305           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1306             {
1307               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1308               new_port0 = udp0->dst_port = s0->in2out.port;
1309               if (PREDICT_FALSE (udp0->checksum))
1310                 {
1311                   sum0 = udp0->checksum;
1312                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
1313                     );
1314                   sum0 =
1315                     ip_csum_update (sum0, old_port0, new_port0,
1316                                     ip4_header_t /* cheat */ ,
1317                                     length /* changed member */ );
1318                   udp0->checksum = ip_csum_fold (sum0);
1319                 }
1320             }
1321           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
1322                                          thread_index, sw_if_index0, 1);
1323         }
1324
1325       /* Accounting */
1326       nat44_ei_session_update_counters (
1327         s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
1328       /* Per-user LRU list maintenance */
1329       nat44_session_update_lru (sm, s0, thread_index);
1330     trace00:
1331
1332       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1333                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1334         {
1335           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
1336           t->sw_if_index = sw_if_index0;
1337           t->next_index = next0;
1338           t->session_index = ~0;
1339           if (s0)
1340             t->session_index =
1341               s0 - sm->per_thread_data[thread_index].sessions;
1342         }
1343
1344       if (next0 == SNAT_OUT2IN_NEXT_DROP)
1345         {
1346           vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
1347                                          thread_index, sw_if_index0, 1);
1348         }
1349
1350       n_left_from--;
1351       next[0] = next0;
1352       next++;
1353     }
1354
1355   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
1356                                frame->n_vectors);
1357
1358   return frame->n_vectors;
1359 }
1360
1361 /* *INDENT-OFF* */
1362 VLIB_REGISTER_NODE (snat_out2in_node) = {
1363   .name = "nat44-out2in",
1364   .vector_size = sizeof (u32),
1365   .format_trace = format_snat_out2in_trace,
1366   .type = VLIB_NODE_TYPE_INTERNAL,
1367
1368   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1369   .error_strings = snat_out2in_error_strings,
1370
1371   .runtime_data_bytes = sizeof (snat_runtime_t),
1372
1373   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1374
1375   /* edit / add dispositions here */
1376   .next_nodes = {
1377     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1378     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1379     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1380   },
1381 };
1382 /* *INDENT-ON* */
1383
1384 VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
1385                                       vlib_node_runtime_t * node,
1386                                       vlib_frame_t * frame)
1387 {
1388   u32 n_left_from, *from;
1389   snat_main_t *sm = &snat_main;
1390
1391   from = vlib_frame_vector_args (frame);
1392   n_left_from = frame->n_vectors;
1393
1394   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
1395   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
1396   vlib_get_buffers (vm, from, b, n_left_from);
1397   while (n_left_from > 0)
1398     {
1399       vlib_buffer_t *b0;
1400       u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1401       u32 sw_if_index0;
1402       ip4_header_t *ip0;
1403       ip_csum_t sum0;
1404       u32 new_addr0, old_addr0;
1405       u16 new_port0, old_port0;
1406       udp_header_t *udp0;
1407       tcp_header_t *tcp0;
1408       icmp46_header_t *icmp0;
1409       u32 proto0;
1410       u32 rx_fib_index0;
1411       ip4_address_t sm_addr0;
1412       u16 sm_port0;
1413       u32 sm_fib_index0;
1414
1415       b0 = *b;
1416       b++;
1417
1418       ip0 = vlib_buffer_get_current (b0);
1419       udp0 = ip4_next_header (ip0);
1420       tcp0 = (tcp_header_t *) udp0;
1421       icmp0 = (icmp46_header_t *) udp0;
1422
1423       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1424       rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1425
1426       vnet_feature_next (&next0, b0);
1427
1428       if (PREDICT_FALSE (ip0->ttl == 1))
1429         {
1430           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1431           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1432                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
1433                                        0);
1434           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1435           goto trace00;
1436         }
1437
1438       proto0 = ip_proto_to_nat_proto (ip0->protocol);
1439
1440       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1441         goto trace00;
1442
1443       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1444         {
1445           next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1446                                rx_fib_index0, node, next0, ~0, 0, 0);
1447           goto trace00;
1448         }
1449
1450       if (nat44_ei_static_mapping_match (ip0->dst_address, udp0->dst_port,
1451                                          rx_fib_index0, proto0, &sm_addr0,
1452                                          &sm_port0, &sm_fib_index0, 1, 0, 0))
1453         {
1454           b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1455           goto trace00;
1456         }
1457
1458       new_addr0 = sm_addr0.as_u32;
1459       new_port0 = sm_port0;
1460       vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm_fib_index0;
1461       old_addr0 = ip0->dst_address.as_u32;
1462       ip0->dst_address.as_u32 = new_addr0;
1463
1464       sum0 = ip0->checksum;
1465       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1466                              ip4_header_t, dst_address /* changed member */ );
1467       ip0->checksum = ip_csum_fold (sum0);
1468
1469       if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1470         {
1471           old_port0 = udp0->dst_port;
1472           udp0->dst_port = new_port0;
1473
1474           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1475             {
1476               sum0 = tcp0->checksum;
1477               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1478                                      ip4_header_t,
1479                                      dst_address /* changed member */ );
1480               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1481                                      ip4_header_t /* cheat */ ,
1482                                      length /* changed member */ );
1483               tcp0->checksum = ip_csum_fold (sum0);
1484             }
1485           else if (udp0->checksum)
1486             {
1487               sum0 = udp0->checksum;
1488               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1489                                      ip4_header_t,
1490                                      dst_address /* changed member */ );
1491               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1492                                      ip4_header_t /* cheat */ ,
1493                                      length /* changed member */ );
1494               udp0->checksum = ip_csum_fold (sum0);
1495             }
1496         }
1497       else
1498         {
1499           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1500             {
1501               sum0 = tcp0->checksum;
1502               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1503                                      ip4_header_t,
1504                                      dst_address /* changed member */ );
1505               tcp0->checksum = ip_csum_fold (sum0);
1506             }
1507           else if (udp0->checksum)
1508             {
1509               sum0 = udp0->checksum;
1510               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1511                                      ip4_header_t,
1512                                      dst_address /* changed member */ );
1513               udp0->checksum = ip_csum_fold (sum0);
1514             }
1515         }
1516
1517     trace00:
1518
1519       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1520                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1521         {
1522           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
1523           t->sw_if_index = sw_if_index0;
1524           t->next_index = next0;
1525         }
1526
1527       if (next0 == SNAT_OUT2IN_NEXT_DROP)
1528         {
1529           vlib_increment_simple_counter (&sm->counters.fastpath.out2in.drops,
1530                                          vm->thread_index, sw_if_index0, 1);
1531         }
1532
1533       n_left_from--;
1534       next[0] = next0;
1535       next++;
1536     }
1537
1538   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
1539                                frame->n_vectors);
1540
1541   return frame->n_vectors;
1542 }
1543
1544 /* *INDENT-OFF* */
1545 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1546   .name = "nat44-out2in-fast",
1547   .vector_size = sizeof (u32),
1548   .format_trace = format_snat_out2in_fast_trace,
1549   .type = VLIB_NODE_TYPE_INTERNAL,
1550
1551   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1552   .error_strings = snat_out2in_error_strings,
1553
1554   .runtime_data_bytes = sizeof (snat_runtime_t),
1555
1556   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1557
1558   /* edit / add dispositions here */
1559   .next_nodes = {
1560     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1561     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1562     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1563   },
1564 };
1565 /* *INDENT-ON* */
1566
1567 /*
1568  * fd.io coding-style-patch-verification: ON
1569  *
1570  * Local Variables:
1571  * eval: (c-set-style "gnu")
1572  * End:
1573  */