src/plugins/nat/out2in.c

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 /**
  16  * @file
  17  * @brief NAT44 endpoint-dependent outside to inside network translation
  18  */
  19
  20 #include <vlib/vlib.h>
  21 #include <vnet/vnet.h>
  22 #include <vnet/pg/pg.h>
  23
  24 #include <vnet/ip/ip.h>
  25 #include <vnet/udp/udp.h>
  26 #include <vnet/ethernet/ethernet.h>
  27 #include <vnet/fib/ip4_fib.h>
  28 #include <nat/nat.h>
  29 #include <nat/nat_ipfix_logging.h>
  30 #include <nat/nat_reass.h>
  31 #include <nat/nat_inlines.h>
  32
  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 vlib_node_registration_t snat_out2in_node;
  72 vlib_node_registration_t snat_out2in_fast_node;
  73 vlib_node_registration_t nat44_out2in_reass_node;
  74
  75 #define foreach_snat_out2in_error                       \
  76 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
  77 _(OUT2IN_PACKETS, "Good out2in packets processed")      \
  78 _(OUT_OF_PORTS, "Out of ports")                         \
  79 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  80 _(NO_TRANSLATION, "No translation")                     \
  81 _(MAX_SESSIONS_EXCEEDED, "Maximum sessions exceeded")   \
  82 _(DROP_FRAGMENT, "Drop fragment")                       \
  83 _(MAX_REASS, "Maximum reassemblies exceeded")           \
  84 _(MAX_FRAG, "Maximum fragments per reassembly exceeded")
  85
  86 typedef enum
  87 {
  88 #define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
  89   foreach_snat_out2in_error
  90 #undef _
  91     SNAT_OUT2IN_N_ERROR,
  92 } snat_out2in_error_t;
  93
  94 static char *snat_out2in_error_strings[] = {
  95 #define _(sym,string) string,
  96   foreach_snat_out2in_error
  97 #undef _
  98 };
  99
 100 typedef enum
 101 {
 102   SNAT_OUT2IN_NEXT_DROP,
 103   SNAT_OUT2IN_NEXT_LOOKUP,
 104   SNAT_OUT2IN_NEXT_ICMP_ERROR,
 105   SNAT_OUT2IN_NEXT_REASS,
 106   SNAT_OUT2IN_N_NEXT,
 107 } snat_out2in_next_t;
 108
 109 int
 110 nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 111 {
 112   snat_main_t *sm = &snat_main;
 113   nat44_is_idle_session_ctx_t *ctx = arg;
 114   snat_session_t *s;
 115   u64 sess_timeout_time;
 116   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
 117                                                        ctx->thread_index);
 118   clib_bihash_kv_8_8_t s_kv;
 119
 120   s = pool_elt_at_index (tsm->sessions, kv->value);
 121   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
 122   if (ctx->now >= sess_timeout_time)
 123     {
 124       s_kv.key = s->in2out.as_u64;
 125       if (clib_bihash_add_del_8_8 (&tsm->in2out, &s_kv, 0))
 126         nat_log_warn ("out2in key del failed");
 127
 128       snat_ipfix_logging_nat44_ses_delete (s->in2out.addr.as_u32,
 129                                            s->out2in.addr.as_u32,
 130                                            s->in2out.protocol,
 131                                            s->in2out.port,
 132                                            s->out2in.port,
 133                                            s->in2out.fib_index);
 134
 135       if (!snat_is_session_static (s))
 136         snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
 137                                             &s->out2in);
 138
 139       nat44_delete_session (sm, s, ctx->thread_index);
 140       return 1;
 141     }
 142
 143   return 0;
 144 }
 145
 146 /**
 147  * @brief Create session for static mapping.
 148  *
 149  * Create NAT session initiated by host from external network with static
 150  * mapping.
 151  *
 152  * @param sm     NAT main.
 153  * @param b0     Vlib buffer.
 154  * @param in2out In2out NAT44 session key.
 155  * @param out2in Out2in NAT44 session key.
 156  * @param node   Vlib node.
 157  *
 158  * @returns SNAT session if successfully created otherwise 0.
 159  */
 160 static inline snat_session_t *
 161 create_session_for_static_mapping (snat_main_t * sm,
 162                                    vlib_buffer_t * b0,
 163                                    snat_session_key_t in2out,
 164                                    snat_session_key_t out2in,
 165                                    vlib_node_runtime_t * node,
 166                                    u32 thread_index, f64 now)
 167 {
 168   snat_user_t *u;
 169   snat_session_t *s;
 170   clib_bihash_kv_8_8_t kv0;
 171   ip4_header_t *ip0;
 172   udp_header_t *udp0;
 173   nat44_is_idle_session_ctx_t ctx0;
 174
 175   if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 176     {
 177       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
 178       nat_log_notice ("maximum sessions exceeded");
 179       return 0;
 180     }
 181
 182   ip0 = vlib_buffer_get_current (b0);
 183   udp0 = ip4_next_header (ip0);
 184
 185   u =
 186     nat_user_get_or_create (sm, &in2out.addr, in2out.fib_index, thread_index);
 187   if (!u)
 188     {
 189       nat_log_warn ("create NAT user failed");
 190       return 0;
 191     }
 192
 193   s = nat_session_alloc_or_recycle (sm, u, thread_index);
 194   if (!s)
 195     {
 196       nat44_delete_user_with_no_session (sm, u, thread_index);
 197       nat_log_warn ("create NAT session failed");
 198       return 0;
 199     }
 200
 201   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 202   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
 203   s->ext_host_port = udp0->src_port;
 204   user_session_increment (sm, u, 1 /* static */ );
 205   s->in2out = in2out;
 206   s->out2in = out2in;
 207   s->in2out.protocol = out2in.protocol;
 208
 209   /* Add to translation hashes */
 210   ctx0.now = now;
 211   ctx0.thread_index = thread_index;
 212   kv0.key = s->in2out.as_u64;
 213   kv0.value = s - sm->per_thread_data[thread_index].sessions;
 214   if (clib_bihash_add_or_overwrite_stale_8_8
 215       (&sm->per_thread_data[thread_index].in2out, &kv0,
 216        nat44_i2o_is_idle_session_cb, &ctx0))
 217     nat_log_notice ("in2out key add failed");
 218
 219   kv0.key = s->out2in.as_u64;
 220
 221   if (clib_bihash_add_or_overwrite_stale_8_8
 222       (&sm->per_thread_data[thread_index].out2in, &kv0,
 223        nat44_o2i_is_idle_session_cb, &ctx0))
 224     nat_log_notice ("out2in key add failed");
 225
 226   /* log NAT event */
 227   snat_ipfix_logging_nat44_ses_create (s->in2out.addr.as_u32,
 228                                        s->out2in.addr.as_u32,
 229                                        s->in2out.protocol,
 230                                        s->in2out.port,
 231                                        s->out2in.port, s->in2out.fib_index);
 232   return s;
 233 }
 234
 235 static_always_inline
 236   snat_out2in_error_t icmp_get_key (ip4_header_t * ip0,
 237                                     snat_session_key_t * p_key0)
 238 {
 239   icmp46_header_t *icmp0;
 240   snat_session_key_t key0;
 241   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 242   ip4_header_t *inner_ip0;
 243   void *l4_header = 0;
 244   icmp46_header_t *inner_icmp0;
 245
 246   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 247   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 248
 249   if (!icmp_is_error_message (icmp0))
 250     {
 251       key0.protocol = SNAT_PROTOCOL_ICMP;
 252       key0.addr = ip0->dst_address;
 253       key0.port = echo0->identifier;
 254     }
 255   else
 256     {
 257       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 258       l4_header = ip4_next_header (inner_ip0);
 259       key0.protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 260       key0.addr = inner_ip0->src_address;
 261       switch (key0.protocol)
 262         {
 263         case SNAT_PROTOCOL_ICMP:
 264           inner_icmp0 = (icmp46_header_t *) l4_header;
 265           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 266           key0.port = inner_echo0->identifier;
 267           break;
 268         case SNAT_PROTOCOL_UDP:
 269         case SNAT_PROTOCOL_TCP:
 270           key0.port = ((tcp_udp_header_t *) l4_header)->src_port;
 271           break;
 272         default:
 273           return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
 274         }
 275     }
 276   *p_key0 = key0;
 277   return -1;                    /* success */
 278 }
 279
 280 /**
 281  * Get address and port values to be used for ICMP packet translation
 282  * and create session if needed
 283  *
 284  * @param[in,out] sm             NAT main
 285  * @param[in,out] node           NAT node runtime
 286  * @param[in] thread_index       thread index
 287  * @param[in,out] b0             buffer containing packet to be translated
 288  * @param[out] p_proto           protocol used for matching
 289  * @param[out] p_value           address and port after NAT translation
 290  * @param[out] p_dont_translate  if packet should not be translated
 291  * @param d                      optional parameter
 292  * @param e                      optional parameter
 293  */
 294 u32
 295 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 296                         u32 thread_index, vlib_buffer_t * b0,
 297                         ip4_header_t * ip0, u8 * p_proto,
 298                         snat_session_key_t * p_value,
 299                         u8 * p_dont_translate, void *d, void *e)
 300 {
 301   icmp46_header_t *icmp0;
 302   u32 sw_if_index0;
 303   u32 rx_fib_index0;
 304   snat_session_key_t key0;
 305   snat_session_key_t sm0;
 306   snat_session_t *s0 = 0;
 307   u8 dont_translate = 0;
 308   clib_bihash_kv_8_8_t kv0, value0;
 309   u8 is_addr_only;
 310   u32 next0 = ~0;
 311   int err;
 312
 313   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 314   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 315   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 316
 317   key0.protocol = 0;
 318
 319   err = icmp_get_key (ip0, &key0);
 320   if (err != -1)
 321     {
 322       b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 323       next0 = SNAT_OUT2IN_NEXT_DROP;
 324       goto out;
 325     }
 326   key0.fib_index = rx_fib_index0;
 327
 328   kv0.key = key0.as_u64;
 329
 330   if (clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].out2in, &kv0,
 331                               &value0))
 332     {
 333       /* Try to match static mapping by external address and port,
 334          destination address and port in packet */
 335       if (snat_static_mapping_match
 336           (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0))
 337         {
 338           if (!sm->forwarding_enabled)
 339             {
 340               /* Don't NAT packet aimed at the intfc address */
 341               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 342                                                     ip0->dst_address.as_u32)))
 343                 {
 344                   dont_translate = 1;
 345                   goto out;
 346                 }
 347               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 348               next0 = SNAT_OUT2IN_NEXT_DROP;
 349               goto out;
 350             }
 351           else
 352             {
 353               dont_translate = 1;
 354               goto out;
 355             }
 356         }
 357
 358       if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
 359                          (icmp0->type != ICMP4_echo_request
 360                           || !is_addr_only)))
 361         {
 362           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 363           next0 = SNAT_OUT2IN_NEXT_DROP;
 364           goto out;
 365         }
 366
 367       /* Create session initiated by host from external network */
 368       s0 = create_session_for_static_mapping (sm, b0, sm0, key0,
 369                                               node, thread_index,
 370                                               vlib_time_now (sm->vlib_main));
 371
 372       if (!s0)
 373         {
 374           next0 = SNAT_OUT2IN_NEXT_DROP;
 375           goto out;
 376         }
 377     }
 378   else
 379     {
 380       if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
 381                          icmp0->type != ICMP4_echo_request &&
 382                          !icmp_is_error_message (icmp0)))
 383         {
 384           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 385           next0 = SNAT_OUT2IN_NEXT_DROP;
 386           goto out;
 387         }
 388
 389       s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 390                               value0.value);
 391     }
 392
 393 out:
 394   *p_proto = key0.protocol;
 395   if (s0)
 396     *p_value = s0->in2out;
 397   *p_dont_translate = dont_translate;
 398   if (d)
 399     *(snat_session_t **) d = s0;
 400   return next0;
 401 }
 402
 403 /**
 404  * Get address and port values to be used for ICMP packet translation
 405  *
 406  * @param[in] sm                 NAT main
 407  * @param[in,out] node           NAT node runtime
 408  * @param[in] thread_index       thread index
 409  * @param[in,out] b0             buffer containing packet to be translated
 410  * @param[out] p_proto           protocol used for matching
 411  * @param[out] p_value           address and port after NAT translation
 412  * @param[out] p_dont_translate  if packet should not be translated
 413  * @param d                      optional parameter
 414  * @param e                      optional parameter
 415  */
 416 u32
 417 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
 418                         u32 thread_index, vlib_buffer_t * b0,
 419                         ip4_header_t * ip0, u8 * p_proto,
 420                         snat_session_key_t * p_value,
 421                         u8 * p_dont_translate, void *d, void *e)
 422 {
 423   icmp46_header_t *icmp0;
 424   u32 sw_if_index0;
 425   u32 rx_fib_index0;
 426   snat_session_key_t key0;
 427   snat_session_key_t sm0;
 428   u8 dont_translate = 0;
 429   u8 is_addr_only;
 430   u32 next0 = ~0;
 431   int err;
 432
 433   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 434   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 435   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 436
 437   err = icmp_get_key (ip0, &key0);
 438   if (err != -1)
 439     {
 440       b0->error = node->errors[err];
 441       next0 = SNAT_OUT2IN_NEXT_DROP;
 442       goto out2;
 443     }
 444   key0.fib_index = rx_fib_index0;
 445
 446   if (snat_static_mapping_match (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0))
 447     {
 448       /* Don't NAT packet aimed at the intfc address */
 449       if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
 450         {
 451           dont_translate = 1;
 452           goto out;
 453         }
 454       b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 455       next0 = SNAT_OUT2IN_NEXT_DROP;
 456       goto out;
 457     }
 458
 459   if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
 460                      (icmp0->type != ICMP4_echo_request || !is_addr_only) &&
 461                      !icmp_is_error_message (icmp0)))
 462     {
 463       b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 464       next0 = SNAT_OUT2IN_NEXT_DROP;
 465       goto out;
 466     }
 467
 468 out:
 469   *p_value = sm0;
 470 out2:
 471   *p_proto = key0.protocol;
 472   *p_dont_translate = dont_translate;
 473   return next0;
 474 }
 475
 476 u32
 477 icmp_out2in (snat_main_t * sm,
 478              vlib_buffer_t * b0,
 479              ip4_header_t * ip0,
 480              icmp46_header_t * icmp0,
 481              u32 sw_if_index0,
 482              u32 rx_fib_index0,
 483              vlib_node_runtime_t * node,
 484              u32 next0, u32 thread_index, void *d, void *e)
 485 {
 486   snat_session_key_t sm0;
 487   u8 protocol;
 488   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 489   ip4_header_t *inner_ip0 = 0;
 490   void *l4_header = 0;
 491   icmp46_header_t *inner_icmp0;
 492   u8 dont_translate;
 493   u32 new_addr0, old_addr0;
 494   u16 old_id0, new_id0;
 495   ip_csum_t sum0;
 496   u16 checksum0;
 497   u32 next0_tmp;
 498
 499   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 500
 501   next0_tmp = sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0,
 502                                         &protocol, &sm0, &dont_translate, d,
 503                                         e);
 504   if (next0_tmp != ~0)
 505     next0 = next0_tmp;
 506   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
 507     goto out;
 508
 509   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 510     {
 511       sum0 = ip_incremental_checksum (0, icmp0,
 512                                       ntohs (ip0->length) -
 513                                       ip4_header_bytes (ip0));
 514       checksum0 = ~ip_csum_fold (sum0);
 515       if (checksum0 != 0 && checksum0 != 0xffff)
 516         {
 517           next0 = SNAT_OUT2IN_NEXT_DROP;
 518           goto out;
 519         }
 520     }
 521
 522   old_addr0 = ip0->dst_address.as_u32;
 523   new_addr0 = ip0->dst_address.as_u32 = sm0.addr.as_u32;
 524   vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
 525
 526   sum0 = ip0->checksum;
 527   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 528                          dst_address /* changed member */ );
 529   ip0->checksum = ip_csum_fold (sum0);
 530
 531   if (icmp0->checksum == 0)
 532     icmp0->checksum = 0xffff;
 533
 534   if (!icmp_is_error_message (icmp0))
 535     {
 536       new_id0 = sm0.port;
 537       if (PREDICT_FALSE (new_id0 != echo0->identifier))
 538         {
 539           old_id0 = echo0->identifier;
 540           new_id0 = sm0.port;
 541           echo0->identifier = new_id0;
 542
 543           sum0 = icmp0->checksum;
 544           sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 545                                  identifier /* changed member */ );
 546           icmp0->checksum = ip_csum_fold (sum0);
 547         }
 548     }
 549   else
 550     {
 551       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 552       l4_header = ip4_next_header (inner_ip0);
 553
 554       if (!ip4_header_checksum_is_valid (inner_ip0))
 555         {
 556           next0 = SNAT_OUT2IN_NEXT_DROP;
 557           goto out;
 558         }
 559
 560       old_addr0 = inner_ip0->src_address.as_u32;
 561       inner_ip0->src_address = sm0.addr;
 562       new_addr0 = inner_ip0->src_address.as_u32;
 563
 564       sum0 = icmp0->checksum;
 565       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 566                              src_address /* changed member */ );
 567       icmp0->checksum = ip_csum_fold (sum0);
 568
 569       switch (protocol)
 570         {
 571         case SNAT_PROTOCOL_ICMP:
 572           inner_icmp0 = (icmp46_header_t *) l4_header;
 573           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 574
 575           old_id0 = inner_echo0->identifier;
 576           new_id0 = sm0.port;
 577           inner_echo0->identifier = new_id0;
 578
 579           sum0 = icmp0->checksum;
 580           sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 581                                  identifier);
 582           icmp0->checksum = ip_csum_fold (sum0);
 583           break;
 584         case SNAT_PROTOCOL_UDP:
 585         case SNAT_PROTOCOL_TCP:
 586           old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 587           new_id0 = sm0.port;
 588           ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 589
 590           sum0 = icmp0->checksum;
 591           sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 592                                  src_port);
 593           icmp0->checksum = ip_csum_fold (sum0);
 594           break;
 595         default:
 596           ASSERT (0);
 597         }
 598     }
 599
 600 out:
 601   return next0;
 602 }
 603
 604
 605 static inline u32
 606 icmp_out2in_slow_path (snat_main_t * sm,
 607                        vlib_buffer_t * b0,
 608                        ip4_header_t * ip0,
 609                        icmp46_header_t * icmp0,
 610                        u32 sw_if_index0,
 611                        u32 rx_fib_index0,
 612                        vlib_node_runtime_t * node,
 613                        u32 next0, f64 now,
 614                        u32 thread_index, snat_session_t ** p_s0)
 615 {
 616   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 617                        next0, thread_index, p_s0, 0);
 618   snat_session_t *s0 = *p_s0;
 619   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
 620     {
 621       /* Accounting */
 622       nat44_session_update_counters (s0, now,
 623                                      vlib_buffer_length_in_chain
 624                                      (sm->vlib_main, b0));
 625       /* Per-user LRU list maintenance */
 626       nat44_session_update_lru (sm, s0, thread_index);
 627     }
 628   return next0;
 629 }
 630
 631 static int
 632 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 633                              vlib_buffer_t * b,
 634                              ip4_header_t * ip, u32 rx_fib_index)
 635 {
 636   clib_bihash_kv_8_8_t kv, value;
 637   snat_static_mapping_t *m;
 638   snat_session_key_t m_key;
 639   u32 old_addr, new_addr;
 640   ip_csum_t sum;
 641
 642   m_key.addr = ip->dst_address;
 643   m_key.port = 0;
 644   m_key.protocol = 0;
 645   m_key.fib_index = 0;
 646   kv.key = m_key.as_u64;
 647   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 648     return 1;
 649
 650   m = pool_elt_at_index (sm->static_mappings, value.value);
 651
 652   old_addr = ip->dst_address.as_u32;
 653   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 654   sum = ip->checksum;
 655   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 656   ip->checksum = ip_csum_fold (sum);
 657
 658   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 659   return 0;
 660 }
 661
 662 static uword
 663 snat_out2in_node_fn (vlib_main_t * vm,
 664                      vlib_node_runtime_t * node, vlib_frame_t * frame)
 665 {
 666   u32 n_left_from, *from, *to_next;
 667   snat_out2in_next_t next_index;
 668   u32 pkts_processed = 0;
 669   snat_main_t *sm = &snat_main;
 670   f64 now = vlib_time_now (vm);
 671   u32 thread_index = vm->thread_index;
 672
 673   from = vlib_frame_vector_args (frame);
 674   n_left_from = frame->n_vectors;
 675   next_index = node->cached_next_index;
 676
 677   while (n_left_from > 0)
 678     {
 679       u32 n_left_to_next;
 680
 681       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 682
 683       while (n_left_from >= 4 && n_left_to_next >= 2)
 684         {
 685           u32 bi0, bi1;
 686           vlib_buffer_t *b0, *b1;
 687           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 688           u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 689           u32 sw_if_index0, sw_if_index1;
 690           ip4_header_t *ip0, *ip1;
 691           ip_csum_t sum0, sum1;
 692           u32 new_addr0, old_addr0;
 693           u16 new_port0, old_port0;
 694           u32 new_addr1, old_addr1;
 695           u16 new_port1, old_port1;
 696           udp_header_t *udp0, *udp1;
 697           tcp_header_t *tcp0, *tcp1;
 698           icmp46_header_t *icmp0, *icmp1;
 699           snat_session_key_t key0, key1, sm0, sm1;
 700           u32 rx_fib_index0, rx_fib_index1;
 701           u32 proto0, proto1;
 702           snat_session_t *s0 = 0, *s1 = 0;
 703           clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
 704
 705           /* Prefetch next iteration. */
 706           {
 707             vlib_buffer_t *p2, *p3;
 708
 709             p2 = vlib_get_buffer (vm, from[2]);
 710             p3 = vlib_get_buffer (vm, from[3]);
 711
 712             vlib_prefetch_buffer_header (p2, LOAD);
 713             vlib_prefetch_buffer_header (p3, LOAD);
 714
 715             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 716             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 717           }
 718
 719           /* speculatively enqueue b0 and b1 to the current next frame */
 720           to_next[0] = bi0 = from[0];
 721           to_next[1] = bi1 = from[1];
 722           from += 2;
 723           to_next += 2;
 724           n_left_from -= 2;
 725           n_left_to_next -= 2;
 726
 727           b0 = vlib_get_buffer (vm, bi0);
 728           b1 = vlib_get_buffer (vm, bi1);
 729
 730           vnet_buffer (b0)->snat.flags = 0;
 731           vnet_buffer (b1)->snat.flags = 0;
 732
 733           ip0 = vlib_buffer_get_current (b0);
 734           udp0 = ip4_next_header (ip0);
 735           tcp0 = (tcp_header_t *) udp0;
 736           icmp0 = (icmp46_header_t *) udp0;
 737
 738           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 739           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 740                                    sw_if_index0);
 741
 742           if (PREDICT_FALSE (ip0->ttl == 1))
 743             {
 744               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 745               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 746                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 747                                            0);
 748               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 749               goto trace0;
 750             }
 751
 752           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 753
 754           if (PREDICT_FALSE (proto0 == ~0))
 755             {
 756               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 757                 {
 758                   if (!sm->forwarding_enabled)
 759                     {
 760                       b0->error =
 761                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 762                       next0 = SNAT_OUT2IN_NEXT_DROP;
 763                     }
 764                 }
 765               goto trace0;
 766             }
 767
 768           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 769             {
 770               next0 = icmp_out2in_slow_path
 771                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 772                  next0, now, thread_index, &s0);
 773               goto trace0;
 774             }
 775
 776           if (PREDICT_FALSE (ip4_is_fragment (ip0)))
 777             {
 778               next0 = SNAT_OUT2IN_NEXT_REASS;
 779               goto trace0;
 780             }
 781
 782           key0.addr = ip0->dst_address;
 783           key0.port = udp0->dst_port;
 784           key0.protocol = proto0;
 785           key0.fib_index = rx_fib_index0;
 786
 787           kv0.key = key0.as_u64;
 788
 789           if (clib_bihash_search_8_8
 790               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
 791             {
 792               /* Try to match static mapping by external address and port,
 793                  destination address and port in packet */
 794               if (snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0))
 795                 {
 796                   /*
 797                    * Send DHCP packets to the ipv4 stack, or we won't
 798                    * be able to use dhcp client on the outside interface
 799                    */
 800                   if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
 801                                      && (udp0->dst_port ==
 802                                          clib_host_to_net_u16
 803                                          (UDP_DST_PORT_dhcp_to_client))))
 804                     {
 805                       vnet_feature_next (&next0, b0);
 806                       goto trace0;
 807                     }
 808
 809                   if (!sm->forwarding_enabled)
 810                     {
 811                       b0->error =
 812                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 813                       next0 = SNAT_OUT2IN_NEXT_DROP;
 814                     }
 815                   goto trace0;
 816                 }
 817
 818               /* Create session initiated by host from external network */
 819               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
 820                                                       thread_index, now);
 821               if (!s0)
 822                 {
 823                   next0 = SNAT_OUT2IN_NEXT_DROP;
 824                   goto trace0;
 825                 }
 826             }
 827           else
 828             s0 =
 829               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 830                                  value0.value);
 831
 832           old_addr0 = ip0->dst_address.as_u32;
 833           ip0->dst_address = s0->in2out.addr;
 834           new_addr0 = ip0->dst_address.as_u32;
 835           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 836
 837           sum0 = ip0->checksum;
 838           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 839                                  ip4_header_t,
 840                                  dst_address /* changed member */ );
 841           ip0->checksum = ip_csum_fold (sum0);
 842
 843           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 844             {
 845               old_port0 = tcp0->dst_port;
 846               tcp0->dst_port = s0->in2out.port;
 847               new_port0 = tcp0->dst_port;
 848
 849               sum0 = tcp0->checksum;
 850               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 851                                      ip4_header_t,
 852                                      dst_address /* changed member */ );
 853
 854               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 855                                      ip4_header_t /* cheat */ ,
 856                                      length /* changed member */ );
 857               tcp0->checksum = ip_csum_fold (sum0);
 858             }
 859           else
 860             {
 861               old_port0 = udp0->dst_port;
 862               udp0->dst_port = s0->in2out.port;
 863               udp0->checksum = 0;
 864             }
 865
 866           /* Accounting */
 867           nat44_session_update_counters (s0, now,
 868                                          vlib_buffer_length_in_chain (vm,
 869                                                                       b0));
 870           /* Per-user LRU list maintenance */
 871           nat44_session_update_lru (sm, s0, thread_index);
 872         trace0:
 873
 874           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 875                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 876             {
 877               snat_out2in_trace_t *t =
 878                 vlib_add_trace (vm, node, b0, sizeof (*t));
 879               t->sw_if_index = sw_if_index0;
 880               t->next_index = next0;
 881               t->session_index = ~0;
 882               if (s0)
 883                 t->session_index =
 884                   s0 - sm->per_thread_data[thread_index].sessions;
 885             }
 886
 887           pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
 888
 889
 890           ip1 = vlib_buffer_get_current (b1);
 891           udp1 = ip4_next_header (ip1);
 892           tcp1 = (tcp_header_t *) udp1;
 893           icmp1 = (icmp46_header_t *) udp1;
 894
 895           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 896           rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 897                                    sw_if_index1);
 898
 899           if (PREDICT_FALSE (ip1->ttl == 1))
 900             {
 901               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 902               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 903                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 904                                            0);
 905               next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 906               goto trace1;
 907             }
 908
 909           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 910
 911           if (PREDICT_FALSE (proto1 == ~0))
 912             {
 913               if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
 914                 {
 915                   if (!sm->forwarding_enabled)
 916                     {
 917                       b1->error =
 918                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 919                       next1 = SNAT_OUT2IN_NEXT_DROP;
 920                     }
 921                 }
 922               goto trace1;
 923             }
 924
 925           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
 926             {
 927               next1 = icmp_out2in_slow_path
 928                 (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
 929                  next1, now, thread_index, &s1);
 930               goto trace1;
 931             }
 932
 933           if (PREDICT_FALSE (ip4_is_fragment (ip1)))
 934             {
 935               next1 = SNAT_OUT2IN_NEXT_REASS;
 936               goto trace1;
 937             }
 938
 939           key1.addr = ip1->dst_address;
 940           key1.port = udp1->dst_port;
 941           key1.protocol = proto1;
 942           key1.fib_index = rx_fib_index1;
 943
 944           kv1.key = key1.as_u64;
 945
 946           if (clib_bihash_search_8_8
 947               (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
 948             {
 949               /* Try to match static mapping by external address and port,
 950                  destination address and port in packet */
 951               if (snat_static_mapping_match (sm, key1, &sm1, 1, 0, 0, 0, 0))
 952                 {
 953                   /*
 954                    * Send DHCP packets to the ipv4 stack, or we won't
 955                    * be able to use dhcp client on the outside interface
 956                    */
 957                   if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_UDP
 958                                      && (udp1->dst_port ==
 959                                          clib_host_to_net_u16
 960                                          (UDP_DST_PORT_dhcp_to_client))))
 961                     {
 962                       vnet_feature_next (&next1, b1);
 963                       goto trace1;
 964                     }
 965
 966                   if (!sm->forwarding_enabled)
 967                     {
 968                       b1->error =
 969                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 970                       next1 = SNAT_OUT2IN_NEXT_DROP;
 971                     }
 972                   goto trace1;
 973                 }
 974
 975               /* Create session initiated by host from external network */
 976               s1 = create_session_for_static_mapping (sm, b1, sm1, key1, node,
 977                                                       thread_index, now);
 978               if (!s1)
 979                 {
 980                   next1 = SNAT_OUT2IN_NEXT_DROP;
 981                   goto trace1;
 982                 }
 983             }
 984           else
 985             s1 =
 986               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 987                                  value1.value);
 988
 989           old_addr1 = ip1->dst_address.as_u32;
 990           ip1->dst_address = s1->in2out.addr;
 991           new_addr1 = ip1->dst_address.as_u32;
 992           vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
 993
 994           sum1 = ip1->checksum;
 995           sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
 996                                  ip4_header_t,
 997                                  dst_address /* changed member */ );
 998           ip1->checksum = ip_csum_fold (sum1);
 999
1000           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
1001             {
1002               old_port1 = tcp1->dst_port;
1003               tcp1->dst_port = s1->in2out.port;
1004               new_port1 = tcp1->dst_port;
1005
1006               sum1 = tcp1->checksum;
1007               sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1008                                      ip4_header_t,
1009                                      dst_address /* changed member */ );
1010
1011               sum1 = ip_csum_update (sum1, old_port1, new_port1,
1012                                      ip4_header_t /* cheat */ ,
1013                                      length /* changed member */ );
1014               tcp1->checksum = ip_csum_fold (sum1);
1015             }
1016           else
1017             {
1018               old_port1 = udp1->dst_port;
1019               udp1->dst_port = s1->in2out.port;
1020               udp1->checksum = 0;
1021             }
1022
1023           /* Accounting */
1024           nat44_session_update_counters (s1, now,
1025                                          vlib_buffer_length_in_chain (vm,
1026                                                                       b1));
1027           /* Per-user LRU list maintenance */
1028           nat44_session_update_lru (sm, s1, thread_index);
1029         trace1:
1030
1031           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1032                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1033             {
1034               snat_out2in_trace_t *t =
1035                 vlib_add_trace (vm, node, b1, sizeof (*t));
1036               t->sw_if_index = sw_if_index1;
1037               t->next_index = next1;
1038               t->session_index = ~0;
1039               if (s1)
1040                 t->session_index =
1041                   s1 - sm->per_thread_data[thread_index].sessions;
1042             }
1043
1044           pkts_processed += next1 != SNAT_OUT2IN_NEXT_DROP;
1045
1046           /* verify speculative enqueues, maybe switch current next frame */
1047           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
1048                                            to_next, n_left_to_next,
1049                                            bi0, bi1, next0, next1);
1050         }
1051
1052       while (n_left_from > 0 && n_left_to_next > 0)
1053         {
1054           u32 bi0;
1055           vlib_buffer_t *b0;
1056           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1057           u32 sw_if_index0;
1058           ip4_header_t *ip0;
1059           ip_csum_t sum0;
1060           u32 new_addr0, old_addr0;
1061           u16 new_port0, old_port0;
1062           udp_header_t *udp0;
1063           tcp_header_t *tcp0;
1064           icmp46_header_t *icmp0;
1065           snat_session_key_t key0, sm0;
1066           u32 rx_fib_index0;
1067           u32 proto0;
1068           snat_session_t *s0 = 0;
1069           clib_bihash_kv_8_8_t kv0, value0;
1070
1071           /* speculatively enqueue b0 to the current next frame */
1072           bi0 = from[0];
1073           to_next[0] = bi0;
1074           from += 1;
1075           to_next += 1;
1076           n_left_from -= 1;
1077           n_left_to_next -= 1;
1078
1079           b0 = vlib_get_buffer (vm, bi0);
1080
1081           vnet_buffer (b0)->snat.flags = 0;
1082
1083           ip0 = vlib_buffer_get_current (b0);
1084           udp0 = ip4_next_header (ip0);
1085           tcp0 = (tcp_header_t *) udp0;
1086           icmp0 = (icmp46_header_t *) udp0;
1087
1088           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1089           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1090                                    sw_if_index0);
1091
1092           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1093
1094           if (PREDICT_FALSE (proto0 == ~0))
1095             {
1096               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1097                 {
1098                   if (!sm->forwarding_enabled)
1099                     {
1100                       b0->error =
1101                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1102                       next0 = SNAT_OUT2IN_NEXT_DROP;
1103                     }
1104                 }
1105               goto trace00;
1106             }
1107
1108           if (PREDICT_FALSE (ip0->ttl == 1))
1109             {
1110               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1111               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1112                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1113                                            0);
1114               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1115               goto trace00;
1116             }
1117
1118           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1119             {
1120               next0 = icmp_out2in_slow_path
1121                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1122                  next0, now, thread_index, &s0);
1123               goto trace00;
1124             }
1125
1126           if (PREDICT_FALSE (ip4_is_fragment (ip0)))
1127             {
1128               next0 = SNAT_OUT2IN_NEXT_REASS;
1129               goto trace00;
1130             }
1131
1132           key0.addr = ip0->dst_address;
1133           key0.port = udp0->dst_port;
1134           key0.protocol = proto0;
1135           key0.fib_index = rx_fib_index0;
1136
1137           kv0.key = key0.as_u64;
1138
1139           if (clib_bihash_search_8_8
1140               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
1141             {
1142               /* Try to match static mapping by external address and port,
1143                  destination address and port in packet */
1144               if (snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0))
1145                 {
1146                   /*
1147                    * Send DHCP packets to the ipv4 stack, or we won't
1148                    * be able to use dhcp client on the outside interface
1149                    */
1150                   if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
1151                                      && (udp0->dst_port ==
1152                                          clib_host_to_net_u16
1153                                          (UDP_DST_PORT_dhcp_to_client))))
1154                     {
1155                       vnet_feature_next (&next0, b0);
1156                       goto trace00;
1157                     }
1158
1159                   if (!sm->forwarding_enabled)
1160                     {
1161                       b0->error =
1162                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1163                       next0 = SNAT_OUT2IN_NEXT_DROP;
1164                     }
1165                   goto trace00;
1166                 }
1167
1168               /* Create session initiated by host from external network */
1169               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
1170                                                       thread_index, now);
1171               if (!s0)
1172                 {
1173                   next0 = SNAT_OUT2IN_NEXT_DROP;
1174                   goto trace00;
1175                 }
1176             }
1177           else
1178             s0 =
1179               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1180                                  value0.value);
1181
1182           old_addr0 = ip0->dst_address.as_u32;
1183           ip0->dst_address = s0->in2out.addr;
1184           new_addr0 = ip0->dst_address.as_u32;
1185           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1186
1187           sum0 = ip0->checksum;
1188           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1189                                  ip4_header_t,
1190                                  dst_address /* changed member */ );
1191           ip0->checksum = ip_csum_fold (sum0);
1192
1193           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1194             {
1195               old_port0 = tcp0->dst_port;
1196               tcp0->dst_port = s0->in2out.port;
1197               new_port0 = tcp0->dst_port;
1198
1199               sum0 = tcp0->checksum;
1200               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1201                                      ip4_header_t,
1202                                      dst_address /* changed member */ );
1203
1204               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1205                                      ip4_header_t /* cheat */ ,
1206                                      length /* changed member */ );
1207               tcp0->checksum = ip_csum_fold (sum0);
1208             }
1209           else
1210             {
1211               old_port0 = udp0->dst_port;
1212               udp0->dst_port = s0->in2out.port;
1213               udp0->checksum = 0;
1214             }
1215
1216           /* Accounting */
1217           nat44_session_update_counters (s0, now,
1218                                          vlib_buffer_length_in_chain (vm,
1219                                                                       b0));
1220           /* Per-user LRU list maintenance */
1221           nat44_session_update_lru (sm, s0, thread_index);
1222         trace00:
1223
1224           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1225                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1226             {
1227               snat_out2in_trace_t *t =
1228                 vlib_add_trace (vm, node, b0, sizeof (*t));
1229               t->sw_if_index = sw_if_index0;
1230               t->next_index = next0;
1231               t->session_index = ~0;
1232               if (s0)
1233                 t->session_index =
1234                   s0 - sm->per_thread_data[thread_index].sessions;
1235             }
1236
1237           pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1238
1239           /* verify speculative enqueue, maybe switch current next frame */
1240           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1241                                            to_next, n_left_to_next,
1242                                            bi0, next0);
1243         }
1244
1245       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1246     }
1247
1248   vlib_node_increment_counter (vm, snat_out2in_node.index,
1249                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1250                                pkts_processed);
1251   return frame->n_vectors;
1252 }
1253
1254 /* *INDENT-OFF* */
1255 VLIB_REGISTER_NODE (snat_out2in_node) = {
1256   .function = snat_out2in_node_fn,
1257   .name = "nat44-out2in",
1258   .vector_size = sizeof (u32),
1259   .format_trace = format_snat_out2in_trace,
1260   .type = VLIB_NODE_TYPE_INTERNAL,
1261
1262   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1263   .error_strings = snat_out2in_error_strings,
1264
1265   .runtime_data_bytes = sizeof (snat_runtime_t),
1266
1267   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1268
1269   /* edit / add dispositions here */
1270   .next_nodes = {
1271     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1272     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1273     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1274     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
1275   },
1276 };
1277 /* *INDENT-ON* */
1278
1279 VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_node, snat_out2in_node_fn);
1280
1281 static uword
1282 nat44_out2in_reass_node_fn (vlib_main_t * vm,
1283                             vlib_node_runtime_t * node, vlib_frame_t * frame)
1284 {
1285   u32 n_left_from, *from, *to_next;
1286   snat_out2in_next_t next_index;
1287   u32 pkts_processed = 0;
1288   snat_main_t *sm = &snat_main;
1289   f64 now = vlib_time_now (vm);
1290   u32 thread_index = vm->thread_index;
1291   snat_main_per_thread_data_t *per_thread_data =
1292     &sm->per_thread_data[thread_index];
1293   u32 *fragments_to_drop = 0;
1294   u32 *fragments_to_loopback = 0;
1295
1296   from = vlib_frame_vector_args (frame);
1297   n_left_from = frame->n_vectors;
1298   next_index = node->cached_next_index;
1299
1300   while (n_left_from > 0)
1301     {
1302       u32 n_left_to_next;
1303
1304       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1305
1306       while (n_left_from > 0 && n_left_to_next > 0)
1307         {
1308           u32 bi0, sw_if_index0, proto0, rx_fib_index0, new_addr0, old_addr0;
1309           vlib_buffer_t *b0;
1310           u32 next0;
1311           u8 cached0 = 0;
1312           ip4_header_t *ip0;
1313           nat_reass_ip4_t *reass0;
1314           udp_header_t *udp0;
1315           tcp_header_t *tcp0;
1316           snat_session_key_t key0, sm0;
1317           clib_bihash_kv_8_8_t kv0, value0;
1318           snat_session_t *s0 = 0;
1319           u16 old_port0, new_port0;
1320           ip_csum_t sum0;
1321
1322           /* speculatively enqueue b0 to the current next frame */
1323           bi0 = from[0];
1324           to_next[0] = bi0;
1325           from += 1;
1326           to_next += 1;
1327           n_left_from -= 1;
1328           n_left_to_next -= 1;
1329
1330           b0 = vlib_get_buffer (vm, bi0);
1331           next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1332
1333           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1334           rx_fib_index0 =
1335             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
1336                                                  sw_if_index0);
1337
1338           if (PREDICT_FALSE (nat_reass_is_drop_frag (0)))
1339             {
1340               next0 = SNAT_OUT2IN_NEXT_DROP;
1341               b0->error = node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT];
1342               goto trace0;
1343             }
1344
1345           ip0 = (ip4_header_t *) vlib_buffer_get_current (b0);
1346           udp0 = ip4_next_header (ip0);
1347           tcp0 = (tcp_header_t *) udp0;
1348           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1349
1350           reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
1351                                                  ip0->dst_address,
1352                                                  ip0->fragment_id,
1353                                                  ip0->protocol,
1354                                                  1, &fragments_to_drop);
1355
1356           if (PREDICT_FALSE (!reass0))
1357             {
1358               next0 = SNAT_OUT2IN_NEXT_DROP;
1359               b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_REASS];
1360               nat_log_notice ("maximum reassemblies exceeded");
1361               goto trace0;
1362             }
1363
1364           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
1365             {
1366               key0.addr = ip0->dst_address;
1367               key0.port = udp0->dst_port;
1368               key0.protocol = proto0;
1369               key0.fib_index = rx_fib_index0;
1370               kv0.key = key0.as_u64;
1371
1372               if (clib_bihash_search_8_8
1373                   (&per_thread_data->out2in, &kv0, &value0))
1374                 {
1375                   /* Try to match static mapping by external address and port,
1376                      destination address and port in packet */
1377                   if (snat_static_mapping_match
1378                       (sm, key0, &sm0, 1, 0, 0, 0, 0))
1379                     {
1380                       /*
1381                        * Send DHCP packets to the ipv4 stack, or we won't
1382                        * be able to use dhcp client on the outside interface
1383                        */
1384                       if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
1385                                          && (udp0->dst_port
1386                                              ==
1387                                              clib_host_to_net_u16
1388                                              (UDP_DST_PORT_dhcp_to_client))))
1389                         {
1390                           vnet_feature_next (&next0, b0);
1391                           goto trace0;
1392                         }
1393
1394                       if (!sm->forwarding_enabled)
1395                         {
1396                           b0->error =
1397                             node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1398                           next0 = SNAT_OUT2IN_NEXT_DROP;
1399                         }
1400                       goto trace0;
1401                     }
1402
1403                   /* Create session initiated by host from external network */
1404                   s0 =
1405                     create_session_for_static_mapping (sm, b0, sm0, key0,
1406                                                        node, thread_index,
1407                                                        now);
1408                   if (!s0)
1409                     {
1410                       b0->error =
1411                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1412                       next0 = SNAT_OUT2IN_NEXT_DROP;
1413                       goto trace0;
1414                     }
1415                   reass0->sess_index = s0 - per_thread_data->sessions;
1416                   reass0->thread_index = thread_index;
1417                 }
1418               else
1419                 {
1420                   s0 = pool_elt_at_index (per_thread_data->sessions,
1421                                           value0.value);
1422                   reass0->sess_index = value0.value;
1423                 }
1424               nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
1425             }
1426           else
1427             {
1428               if (PREDICT_FALSE (reass0->sess_index == (u32) ~ 0))
1429                 {
1430                   if (nat_ip4_reass_add_fragment
1431                       (reass0, bi0, &fragments_to_drop))
1432                     {
1433                       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_FRAG];
1434                       nat_log_notice
1435                         ("maximum fragments per reassembly exceeded");
1436                       next0 = SNAT_OUT2IN_NEXT_DROP;
1437                       goto trace0;
1438                     }
1439                   cached0 = 1;
1440                   goto trace0;
1441                 }
1442               s0 = pool_elt_at_index (per_thread_data->sessions,
1443                                       reass0->sess_index);
1444             }
1445
1446           old_addr0 = ip0->dst_address.as_u32;
1447           ip0->dst_address = s0->in2out.addr;
1448           new_addr0 = ip0->dst_address.as_u32;
1449           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1450
1451           sum0 = ip0->checksum;
1452           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1453                                  ip4_header_t,
1454                                  dst_address /* changed member */ );
1455           ip0->checksum = ip_csum_fold (sum0);
1456
1457           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
1458             {
1459               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1460                 {
1461                   old_port0 = tcp0->dst_port;
1462                   tcp0->dst_port = s0->in2out.port;
1463                   new_port0 = tcp0->dst_port;
1464
1465                   sum0 = tcp0->checksum;
1466                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1467                                          ip4_header_t,
1468                                          dst_address /* changed member */ );
1469
1470                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1471                                          ip4_header_t /* cheat */ ,
1472                                          length /* changed member */ );
1473                   tcp0->checksum = ip_csum_fold (sum0);
1474                 }
1475               else
1476                 {
1477                   old_port0 = udp0->dst_port;
1478                   udp0->dst_port = s0->in2out.port;
1479                   udp0->checksum = 0;
1480                 }
1481             }
1482
1483           /* Accounting */
1484           nat44_session_update_counters (s0, now,
1485                                          vlib_buffer_length_in_chain (vm,
1486                                                                       b0));
1487           /* Per-user LRU list maintenance */
1488           nat44_session_update_lru (sm, s0, thread_index);
1489
1490         trace0:
1491           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1492                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1493             {
1494               nat44_reass_trace_t *t =
1495                 vlib_add_trace (vm, node, b0, sizeof (*t));
1496               t->cached = cached0;
1497               t->sw_if_index = sw_if_index0;
1498               t->next_index = next0;
1499             }
1500
1501           if (cached0)
1502             {
1503               n_left_to_next++;
1504               to_next--;
1505             }
1506           else
1507             {
1508               pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1509
1510               /* verify speculative enqueue, maybe switch current next frame */
1511               vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1512                                                to_next, n_left_to_next,
1513                                                bi0, next0);
1514             }
1515
1516           if (n_left_from == 0 && vec_len (fragments_to_loopback))
1517             {
1518               from = vlib_frame_vector_args (frame);
1519               u32 len = vec_len (fragments_to_loopback);
1520               if (len <= VLIB_FRAME_SIZE)
1521                 {
1522                   clib_memcpy (from, fragments_to_loopback,
1523                                sizeof (u32) * len);
1524                   n_left_from = len;
1525                   vec_reset_length (fragments_to_loopback);
1526                 }
1527               else
1528                 {
1529                   clib_memcpy (from,
1530                                fragments_to_loopback + (len -
1531                                                         VLIB_FRAME_SIZE),
1532                                sizeof (u32) * VLIB_FRAME_SIZE);
1533                   n_left_from = VLIB_FRAME_SIZE;
1534                   _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
1535                 }
1536             }
1537         }
1538
1539       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1540     }
1541
1542   vlib_node_increment_counter (vm, nat44_out2in_reass_node.index,
1543                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1544                                pkts_processed);
1545
1546   nat_send_all_to_node (vm, fragments_to_drop, node,
1547                         &node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT],
1548                         SNAT_OUT2IN_NEXT_DROP);
1549
1550   vec_free (fragments_to_drop);
1551   vec_free (fragments_to_loopback);
1552   return frame->n_vectors;
1553 }
1554
1555 /* *INDENT-OFF* */
1556 VLIB_REGISTER_NODE (nat44_out2in_reass_node) = {
1557   .function = nat44_out2in_reass_node_fn,
1558   .name = "nat44-out2in-reass",
1559   .vector_size = sizeof (u32),
1560   .format_trace = format_nat44_reass_trace,
1561   .type = VLIB_NODE_TYPE_INTERNAL,
1562
1563   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1564   .error_strings = snat_out2in_error_strings,
1565
1566   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1567
1568   /* edit / add dispositions here */
1569   .next_nodes = {
1570     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1571     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1572     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1573     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
1574   },
1575 };
1576 /* *INDENT-ON* */
1577
1578 VLIB_NODE_FUNCTION_MULTIARCH (nat44_out2in_reass_node,
1579                               nat44_out2in_reass_node_fn);
1580
1581 static uword
1582 snat_out2in_fast_node_fn (vlib_main_t * vm,
1583                           vlib_node_runtime_t * node, vlib_frame_t * frame)
1584 {
1585   u32 n_left_from, *from, *to_next;
1586   snat_out2in_next_t next_index;
1587   u32 pkts_processed = 0;
1588   snat_main_t *sm = &snat_main;
1589
1590   from = vlib_frame_vector_args (frame);
1591   n_left_from = frame->n_vectors;
1592   next_index = node->cached_next_index;
1593
1594   while (n_left_from > 0)
1595     {
1596       u32 n_left_to_next;
1597
1598       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1599
1600       while (n_left_from > 0 && n_left_to_next > 0)
1601         {
1602           u32 bi0;
1603           vlib_buffer_t *b0;
1604           u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1605           u32 sw_if_index0;
1606           ip4_header_t *ip0;
1607           ip_csum_t sum0;
1608           u32 new_addr0, old_addr0;
1609           u16 new_port0, old_port0;
1610           udp_header_t *udp0;
1611           tcp_header_t *tcp0;
1612           icmp46_header_t *icmp0;
1613           snat_session_key_t key0, sm0;
1614           u32 proto0;
1615           u32 rx_fib_index0;
1616
1617           /* speculatively enqueue b0 to the current next frame */
1618           bi0 = from[0];
1619           to_next[0] = bi0;
1620           from += 1;
1621           to_next += 1;
1622           n_left_from -= 1;
1623           n_left_to_next -= 1;
1624
1625           b0 = vlib_get_buffer (vm, bi0);
1626
1627           ip0 = vlib_buffer_get_current (b0);
1628           udp0 = ip4_next_header (ip0);
1629           tcp0 = (tcp_header_t *) udp0;
1630           icmp0 = (icmp46_header_t *) udp0;
1631
1632           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1633           rx_fib_index0 =
1634             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1635
1636           vnet_feature_next (&next0, b0);
1637
1638           if (PREDICT_FALSE (ip0->ttl == 1))
1639             {
1640               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1641               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1642                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1643                                            0);
1644               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1645               goto trace00;
1646             }
1647
1648           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1649
1650           if (PREDICT_FALSE (proto0 == ~0))
1651             goto trace00;
1652
1653           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1654             {
1655               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1656                                    rx_fib_index0, node, next0, ~0, 0, 0);
1657               goto trace00;
1658             }
1659
1660           key0.addr = ip0->dst_address;
1661           key0.port = udp0->dst_port;
1662           key0.fib_index = rx_fib_index0;
1663
1664           if (snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0))
1665             {
1666               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1667               goto trace00;
1668             }
1669
1670           new_addr0 = sm0.addr.as_u32;
1671           new_port0 = sm0.port;
1672           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
1673           old_addr0 = ip0->dst_address.as_u32;
1674           ip0->dst_address.as_u32 = new_addr0;
1675
1676           sum0 = ip0->checksum;
1677           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1678                                  ip4_header_t,
1679                                  dst_address /* changed member */ );
1680           ip0->checksum = ip_csum_fold (sum0);
1681
1682           if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1683             {
1684               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1685                 {
1686                   old_port0 = tcp0->dst_port;
1687                   tcp0->dst_port = new_port0;
1688
1689                   sum0 = tcp0->checksum;
1690                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1691                                          ip4_header_t,
1692                                          dst_address /* changed member */ );
1693
1694                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1695                                          ip4_header_t /* cheat */ ,
1696                                          length /* changed member */ );
1697                   tcp0->checksum = ip_csum_fold (sum0);
1698                 }
1699               else
1700                 {
1701                   old_port0 = udp0->dst_port;
1702                   udp0->dst_port = new_port0;
1703                   udp0->checksum = 0;
1704                 }
1705             }
1706           else
1707             {
1708               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1709                 {
1710                   sum0 = tcp0->checksum;
1711                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1712                                          ip4_header_t,
1713                                          dst_address /* changed member */ );
1714
1715                   tcp0->checksum = ip_csum_fold (sum0);
1716                 }
1717             }
1718
1719         trace00:
1720
1721           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1722                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1723             {
1724               snat_out2in_trace_t *t =
1725                 vlib_add_trace (vm, node, b0, sizeof (*t));
1726               t->sw_if_index = sw_if_index0;
1727               t->next_index = next0;
1728             }
1729
1730           pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1731
1732           /* verify speculative enqueue, maybe switch current next frame */
1733           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1734                                            to_next, n_left_to_next,
1735                                            bi0, next0);
1736         }
1737
1738       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1739     }
1740
1741   vlib_node_increment_counter (vm, snat_out2in_fast_node.index,
1742                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1743                                pkts_processed);
1744   return frame->n_vectors;
1745 }
1746
1747 /* *INDENT-OFF* */
1748 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1749   .function = snat_out2in_fast_node_fn,
1750   .name = "nat44-out2in-fast",
1751   .vector_size = sizeof (u32),
1752   .format_trace = format_snat_out2in_fast_trace,
1753   .type = VLIB_NODE_TYPE_INTERNAL,
1754
1755   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1756   .error_strings = snat_out2in_error_strings,
1757
1758   .runtime_data_bytes = sizeof (snat_runtime_t),
1759
1760   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1761
1762   /* edit / add dispositions here */
1763   .next_nodes = {
1764     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1765     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1766     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1767     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
1768   },
1769 };
1770 /* *INDENT-ON* */
1771
1772 VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_fast_node,
1773                               snat_out2in_fast_node_fn);
1774
1775 /*
1776  * fd.io coding-style-patch-verification: ON
1777  *
1778  * Local Variables:
1779  * eval: (c-set-style "gnu")
1780  * End:
1781  */