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_inlines.h>
  31 #include <nat/nat44_inlines.h>
  32 #include <nat/nat_syslog.h>
  33 #include <nat/nat_ha.h>
  34
  35 #include <vppinfra/hash.h>
  36 #include <vppinfra/error.h>
  37 #include <vppinfra/elog.h>
  38
  39 typedef struct
  40 {
  41   u32 sw_if_index;
  42   u32 next_index;
  43   u32 session_index;
  44 } snat_out2in_trace_t;
  45
  46 /* packet trace format function */
  47 static u8 *
  48 format_snat_out2in_trace (u8 * s, va_list * args)
  49 {
  50   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  51   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  52   snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
  53
  54   s =
  55     format (s,
  56             "NAT44_OUT2IN: sw_if_index %d, next index %d, session index %d",
  57             t->sw_if_index, t->next_index, t->session_index);
  58   return s;
  59 }
  60
  61 static u8 *
  62 format_snat_out2in_fast_trace (u8 * s, va_list * args)
  63 {
  64   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  65   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  66   snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
  67
  68   s = format (s, "NAT44_OUT2IN_FAST: sw_if_index %d, next index %d",
  69               t->sw_if_index, t->next_index);
  70   return s;
  71 }
  72
  73 #define foreach_snat_out2in_error                       \
  74 _(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
  75 _(OUT2IN_PACKETS, "good out2in packets processed")      \
  76 _(OUT_OF_PORTS, "out of ports")                         \
  77 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
  78 _(NO_TRANSLATION, "no translation")                     \
  79 _(MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")   \
  80 _(DROP_FRAGMENT, "drop fragment")                       \
  81 _(MAX_REASS, "maximum reassemblies exceeded")           \
  82 _(MAX_FRAG, "maximum fragments per reassembly exceeded")\
  83 _(TCP_PACKETS, "TCP packets")                           \
  84 _(UDP_PACKETS, "UDP packets")                           \
  85 _(ICMP_PACKETS, "ICMP packets")                         \
  86 _(OTHER_PACKETS, "other protocol packets")              \
  87 _(FRAGMENTS, "fragments")                               \
  88 _(CACHED_FRAGMENTS, "cached fragments")                 \
  89 _(PROCESSED_FRAGMENTS, "processed fragments")
  90
  91 typedef enum
  92 {
  93 #define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
  94   foreach_snat_out2in_error
  95 #undef _
  96     SNAT_OUT2IN_N_ERROR,
  97 } snat_out2in_error_t;
  98
  99 static char *snat_out2in_error_strings[] = {
 100 #define _(sym,string) string,
 101   foreach_snat_out2in_error
 102 #undef _
 103 };
 104
 105 typedef enum
 106 {
 107   SNAT_OUT2IN_NEXT_DROP,
 108   SNAT_OUT2IN_NEXT_LOOKUP,
 109   SNAT_OUT2IN_NEXT_ICMP_ERROR,
 110   SNAT_OUT2IN_N_NEXT,
 111 } snat_out2in_next_t;
 112
 113 #ifndef CLIB_MARCH_VARIANT
 114 int
 115 nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 116 {
 117   snat_main_t *sm = &snat_main;
 118   nat44_is_idle_session_ctx_t *ctx = arg;
 119   snat_session_t *s;
 120   u64 sess_timeout_time;
 121   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
 122                                                        ctx->thread_index);
 123   clib_bihash_kv_8_8_t s_kv;
 124
 125   s = pool_elt_at_index (tsm->sessions, kv->value);
 126   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
 127   if (ctx->now >= sess_timeout_time)
 128     {
 129       s_kv.key = s->in2out.as_u64;
 130       if (clib_bihash_add_del_8_8 (&tsm->in2out, &s_kv, 0))
 131         nat_elog_warn ("out2in key del failed");
 132
 133       snat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
 134                                            s->in2out.addr.as_u32,
 135                                            s->out2in.addr.as_u32,
 136                                            s->in2out.protocol,
 137                                            s->in2out.port,
 138                                            s->out2in.port,
 139                                            s->in2out.fib_index);
 140
 141       nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
 142                                &s->in2out.addr, s->in2out.port,
 143                                &s->out2in.addr, s->out2in.port,
 144                                s->in2out.protocol);
 145
 146       nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
 147                    s->ext_host_port, s->out2in.protocol, s->out2in.fib_index,
 148                    ctx->thread_index);
 149
 150       if (!snat_is_session_static (s))
 151         snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
 152                                             &s->out2in);
 153
 154       nat44_delete_session (sm, s, ctx->thread_index);
 155       return 1;
 156     }
 157
 158   return 0;
 159 }
 160 #endif
 161
 162 /**
 163  * @brief Create session for static mapping.
 164  *
 165  * Create NAT session initiated by host from external network with static
 166  * mapping.
 167  *
 168  * @param sm     NAT main.
 169  * @param b0     Vlib buffer.
 170  * @param in2out In2out NAT44 session key.
 171  * @param out2in Out2in NAT44 session key.
 172  * @param node   Vlib node.
 173  *
 174  * @returns SNAT session if successfully created otherwise 0.
 175  */
 176 static inline snat_session_t *
 177 create_session_for_static_mapping (snat_main_t * sm,
 178                                    vlib_buffer_t * b0,
 179                                    snat_session_key_t in2out,
 180                                    snat_session_key_t out2in,
 181                                    vlib_node_runtime_t * node,
 182                                    u32 thread_index, f64 now)
 183 {
 184   snat_user_t *u;
 185   snat_session_t *s;
 186   clib_bihash_kv_8_8_t kv0;
 187   ip4_header_t *ip0;
 188   udp_header_t *udp0;
 189   nat44_is_idle_session_ctx_t ctx0;
 190
 191   nat44_session_try_cleanup (&in2out.addr, in2out.fib_index, thread_index,
 192                              now);
 193
 194   if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
 195     {
 196       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
 197       nat_elog_notice ("maximum sessions exceeded");
 198       return 0;
 199     }
 200
 201   ip0 = vlib_buffer_get_current (b0);
 202   udp0 = ip4_next_header (ip0);
 203
 204   u =
 205     nat_user_get_or_create (sm, &in2out.addr, in2out.fib_index, thread_index);
 206   if (!u)
 207     {
 208       nat_elog_warn ("create NAT user failed");
 209       return 0;
 210     }
 211
 212   s = nat_session_alloc_or_recycle (sm, u, thread_index, now);
 213   if (!s)
 214     {
 215       nat44_delete_user_with_no_session (sm, u, thread_index);
 216       nat_elog_warn ("create NAT session failed");
 217       return 0;
 218     }
 219
 220   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 221   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
 222   s->ext_host_port = udp0->src_port;
 223   user_session_increment (sm, u, 1 /* static */ );
 224   s->in2out = in2out;
 225   s->out2in = out2in;
 226   s->in2out.protocol = out2in.protocol;
 227
 228   /* Add to translation hashes */
 229   ctx0.now = now;
 230   ctx0.thread_index = thread_index;
 231   kv0.key = s->in2out.as_u64;
 232   kv0.value = s - sm->per_thread_data[thread_index].sessions;
 233   if (clib_bihash_add_or_overwrite_stale_8_8
 234       (&sm->per_thread_data[thread_index].in2out, &kv0,
 235        nat44_i2o_is_idle_session_cb, &ctx0))
 236     nat_elog_notice ("in2out key add failed");
 237
 238   kv0.key = s->out2in.as_u64;
 239
 240   if (clib_bihash_add_or_overwrite_stale_8_8
 241       (&sm->per_thread_data[thread_index].out2in, &kv0,
 242        nat44_o2i_is_idle_session_cb, &ctx0))
 243     nat_elog_notice ("out2in key add failed");
 244
 245   /* log NAT event */
 246   snat_ipfix_logging_nat44_ses_create (thread_index,
 247                                        s->in2out.addr.as_u32,
 248                                        s->out2in.addr.as_u32,
 249                                        s->in2out.protocol,
 250                                        s->in2out.port,
 251                                        s->out2in.port, s->in2out.fib_index);
 252
 253   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
 254                            &s->in2out.addr, s->in2out.port, &s->out2in.addr,
 255                            s->out2in.port, s->in2out.protocol);
 256
 257   nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
 258                s->out2in.port, &s->ext_host_addr, s->ext_host_port,
 259                &s->ext_host_nat_addr, s->ext_host_nat_port,
 260                s->in2out.protocol, s->in2out.fib_index, s->flags,
 261                thread_index, 0);
 262
 263   return s;
 264 }
 265
 266 #ifndef CLIB_MARCH_VARIANT
 267 static_always_inline
 268   snat_out2in_error_t icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
 269                                     snat_session_key_t * p_key0)
 270 {
 271   icmp46_header_t *icmp0;
 272   snat_session_key_t key0;
 273   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 274   ip4_header_t *inner_ip0;
 275   void *l4_header = 0;
 276   icmp46_header_t *inner_icmp0;
 277
 278   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 279   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 280
 281   if (!icmp_type_is_error_message
 282       (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
 283     {
 284       key0.protocol = SNAT_PROTOCOL_ICMP;
 285       key0.addr = ip0->dst_address;
 286       key0.port = vnet_buffer (b)->ip.reass.l4_src_port;        // TODO should this be dst port?
 287     }
 288   else
 289     {
 290       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 291       l4_header = ip4_next_header (inner_ip0);
 292       key0.protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 293       key0.addr = inner_ip0->src_address;
 294       switch (key0.protocol)
 295         {
 296         case SNAT_PROTOCOL_ICMP:
 297           inner_icmp0 = (icmp46_header_t *) l4_header;
 298           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 299           key0.port = inner_echo0->identifier;
 300           break;
 301         case SNAT_PROTOCOL_UDP:
 302         case SNAT_PROTOCOL_TCP:
 303           key0.port = ((tcp_udp_header_t *) l4_header)->src_port;
 304           break;
 305         default:
 306           return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
 307         }
 308     }
 309   *p_key0 = key0;
 310   return -1;                    /* success */
 311 }
 312
 313 /**
 314  * Get address and port values to be used for ICMP packet translation
 315  * and create session if needed
 316  *
 317  * @param[in,out] sm             NAT main
 318  * @param[in,out] node           NAT node runtime
 319  * @param[in] thread_index       thread index
 320  * @param[in,out] b0             buffer containing packet to be translated
 321  * @param[out] p_proto           protocol used for matching
 322  * @param[out] p_value           address and port after NAT translation
 323  * @param[out] p_dont_translate  if packet should not be translated
 324  * @param d                      optional parameter
 325  * @param e                      optional parameter
 326  */
 327 u32
 328 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 329                         u32 thread_index, vlib_buffer_t * b0,
 330                         ip4_header_t * ip0, u8 * p_proto,
 331                         snat_session_key_t * p_value,
 332                         u8 * p_dont_translate, void *d, void *e)
 333 {
 334   u32 sw_if_index0;
 335   u32 rx_fib_index0;
 336   snat_session_key_t key0;
 337   snat_session_key_t sm0;
 338   snat_session_t *s0 = 0;
 339   u8 dont_translate = 0;
 340   clib_bihash_kv_8_8_t kv0, value0;
 341   u8 is_addr_only;
 342   u32 next0 = ~0;
 343   int err;
 344   u8 identity_nat;
 345
 346   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 347   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 348
 349   key0.protocol = 0;
 350
 351   err = icmp_get_key (b0, ip0, &key0);
 352   if (err != -1)
 353     {
 354       b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 355       next0 = SNAT_OUT2IN_NEXT_DROP;
 356       goto out;
 357     }
 358   key0.fib_index = rx_fib_index0;
 359
 360   kv0.key = key0.as_u64;
 361
 362   if (clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].out2in, &kv0,
 363                               &value0))
 364     {
 365       /* Try to match static mapping by external address and port,
 366          destination address and port in packet */
 367       if (snat_static_mapping_match
 368           (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0, &identity_nat))
 369         {
 370           if (!sm->forwarding_enabled)
 371             {
 372               /* Don't NAT packet aimed at the intfc address */
 373               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 374                                                     ip0->dst_address.as_u32)))
 375                 {
 376                   dont_translate = 1;
 377                   goto out;
 378                 }
 379               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 380               next0 = SNAT_OUT2IN_NEXT_DROP;
 381               goto out;
 382             }
 383           else
 384             {
 385               dont_translate = 1;
 386               goto out;
 387             }
 388         }
 389
 390       if (PREDICT_FALSE
 391           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 392            ICMP4_echo_reply
 393            && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 394                ICMP4_echo_request || !is_addr_only)))
 395         {
 396           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 397           next0 = SNAT_OUT2IN_NEXT_DROP;
 398           goto out;
 399         }
 400
 401       if (PREDICT_FALSE (identity_nat))
 402         {
 403           dont_translate = 1;
 404           goto out;
 405         }
 406       /* Create session initiated by host from external network */
 407       s0 = create_session_for_static_mapping (sm, b0, sm0, key0,
 408                                               node, thread_index,
 409                                               vlib_time_now (sm->vlib_main));
 410
 411       if (!s0)
 412         {
 413           next0 = SNAT_OUT2IN_NEXT_DROP;
 414           goto out;
 415         }
 416     }
 417   else
 418     {
 419       if (PREDICT_FALSE
 420           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 421            ICMP4_echo_reply
 422            && vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 423            ICMP4_echo_request
 424            && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 425                                            reass.icmp_type_or_tcp_flags)))
 426         {
 427           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 428           next0 = SNAT_OUT2IN_NEXT_DROP;
 429           goto out;
 430         }
 431
 432       s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 433                               value0.value);
 434     }
 435
 436 out:
 437   *p_proto = key0.protocol;
 438   if (s0)
 439     *p_value = s0->in2out;
 440   *p_dont_translate = dont_translate;
 441   if (d)
 442     *(snat_session_t **) d = s0;
 443   return next0;
 444 }
 445 #endif
 446
 447 #ifndef CLIB_MARCH_VARIANT
 448 /**
 449  * Get address and port values to be used for ICMP packet translation
 450  *
 451  * @param[in] sm                 NAT main
 452  * @param[in,out] node           NAT node runtime
 453  * @param[in] thread_index       thread index
 454  * @param[in,out] b0             buffer containing packet to be translated
 455  * @param[out] p_proto           protocol used for matching
 456  * @param[out] p_value           address and port after NAT translation
 457  * @param[out] p_dont_translate  if packet should not be translated
 458  * @param d                      optional parameter
 459  * @param e                      optional parameter
 460  */
 461 u32
 462 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
 463                         u32 thread_index, vlib_buffer_t * b0,
 464                         ip4_header_t * ip0, u8 * p_proto,
 465                         snat_session_key_t * p_value,
 466                         u8 * p_dont_translate, void *d, void *e)
 467 {
 468   u32 sw_if_index0;
 469   u32 rx_fib_index0;
 470   snat_session_key_t key0;
 471   snat_session_key_t sm0;
 472   u8 dont_translate = 0;
 473   u8 is_addr_only;
 474   u32 next0 = ~0;
 475   int err;
 476
 477   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 478   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 479
 480   err = icmp_get_key (b0, ip0, &key0);
 481   if (err != -1)
 482     {
 483       b0->error = node->errors[err];
 484       next0 = SNAT_OUT2IN_NEXT_DROP;
 485       goto out2;
 486     }
 487   key0.fib_index = rx_fib_index0;
 488
 489   if (snat_static_mapping_match
 490       (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0, 0))
 491     {
 492       /* Don't NAT packet aimed at the intfc address */
 493       if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
 494         {
 495           dont_translate = 1;
 496           goto out;
 497         }
 498       b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 499       next0 = SNAT_OUT2IN_NEXT_DROP;
 500       goto out;
 501     }
 502
 503   if (PREDICT_FALSE
 504       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
 505        && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 506            ICMP4_echo_request || !is_addr_only)
 507        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 508                                        reass.icmp_type_or_tcp_flags)))
 509     {
 510       b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 511       next0 = SNAT_OUT2IN_NEXT_DROP;
 512       goto out;
 513     }
 514
 515 out:
 516   *p_value = sm0;
 517 out2:
 518   *p_proto = key0.protocol;
 519   *p_dont_translate = dont_translate;
 520   return next0;
 521 }
 522 #endif
 523
 524 #ifndef CLIB_MARCH_VARIANT
 525 u32
 526 icmp_out2in (snat_main_t * sm,
 527              vlib_buffer_t * b0,
 528              ip4_header_t * ip0,
 529              icmp46_header_t * icmp0,
 530              u32 sw_if_index0,
 531              u32 rx_fib_index0,
 532              vlib_node_runtime_t * node,
 533              u32 next0, u32 thread_index, void *d, void *e)
 534 {
 535   snat_session_key_t sm0;
 536   u8 protocol;
 537   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 538   ip4_header_t *inner_ip0 = 0;
 539   void *l4_header = 0;
 540   icmp46_header_t *inner_icmp0;
 541   u8 dont_translate;
 542   u32 new_addr0, old_addr0;
 543   u16 old_id0, new_id0;
 544   ip_csum_t sum0;
 545   u16 checksum0;
 546   u32 next0_tmp;
 547
 548   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 549
 550   next0_tmp = sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0,
 551                                         &protocol, &sm0, &dont_translate, d,
 552                                         e);
 553   if (next0_tmp != ~0)
 554     next0 = next0_tmp;
 555   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
 556     goto out;
 557
 558   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 559     {
 560       sum0 = ip_incremental_checksum_buffer (sm->vlib_main, b0, (u8 *) icmp0 -
 561                                              (u8 *)
 562                                              vlib_buffer_get_current (b0),
 563                                              ntohs (ip0->length) -
 564                                              ip4_header_bytes (ip0), 0);
 565       checksum0 = ~ip_csum_fold (sum0);
 566       if (checksum0 != 0 && checksum0 != 0xffff)
 567         {
 568           next0 = SNAT_OUT2IN_NEXT_DROP;
 569           goto out;
 570         }
 571     }
 572
 573   old_addr0 = ip0->dst_address.as_u32;
 574   new_addr0 = ip0->dst_address.as_u32 = sm0.addr.as_u32;
 575   vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
 576
 577   sum0 = ip0->checksum;
 578   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 579                          dst_address /* changed member */ );
 580   ip0->checksum = ip_csum_fold (sum0);
 581
 582
 583   if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 584     {
 585       if (icmp0->checksum == 0)
 586         icmp0->checksum = 0xffff;
 587
 588       if (!icmp_type_is_error_message (icmp0->type))
 589         {
 590           new_id0 = sm0.port;
 591           if (PREDICT_FALSE (new_id0 != echo0->identifier))
 592             {
 593               old_id0 = echo0->identifier;
 594               new_id0 = sm0.port;
 595               echo0->identifier = new_id0;
 596
 597               sum0 = icmp0->checksum;
 598               sum0 =
 599                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 600                                 identifier /* changed member */ );
 601               icmp0->checksum = ip_csum_fold (sum0);
 602             }
 603         }
 604       else
 605         {
 606           inner_ip0 = (ip4_header_t *) (echo0 + 1);
 607           l4_header = ip4_next_header (inner_ip0);
 608
 609           if (!ip4_header_checksum_is_valid (inner_ip0))
 610             {
 611               next0 = SNAT_OUT2IN_NEXT_DROP;
 612               goto out;
 613             }
 614
 615           old_addr0 = inner_ip0->src_address.as_u32;
 616           inner_ip0->src_address = sm0.addr;
 617           new_addr0 = inner_ip0->src_address.as_u32;
 618
 619           sum0 = icmp0->checksum;
 620           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 621                                  src_address /* changed member */ );
 622           icmp0->checksum = ip_csum_fold (sum0);
 623
 624           switch (protocol)
 625             {
 626             case SNAT_PROTOCOL_ICMP:
 627               inner_icmp0 = (icmp46_header_t *) l4_header;
 628               inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 629
 630               old_id0 = inner_echo0->identifier;
 631               new_id0 = sm0.port;
 632               inner_echo0->identifier = new_id0;
 633
 634               sum0 = icmp0->checksum;
 635               sum0 =
 636                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 637                                 identifier);
 638               icmp0->checksum = ip_csum_fold (sum0);
 639               break;
 640             case SNAT_PROTOCOL_UDP:
 641             case SNAT_PROTOCOL_TCP:
 642               old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 643               new_id0 = sm0.port;
 644               ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 645
 646               sum0 = icmp0->checksum;
 647               sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 648                                      src_port);
 649               icmp0->checksum = ip_csum_fold (sum0);
 650               break;
 651             default:
 652               ASSERT (0);
 653             }
 654         }
 655     }
 656
 657 out:
 658   return next0;
 659 }
 660 #endif
 661
 662 static inline u32
 663 icmp_out2in_slow_path (snat_main_t * sm,
 664                        vlib_buffer_t * b0,
 665                        ip4_header_t * ip0,
 666                        icmp46_header_t * icmp0,
 667                        u32 sw_if_index0,
 668                        u32 rx_fib_index0,
 669                        vlib_node_runtime_t * node,
 670                        u32 next0, f64 now,
 671                        u32 thread_index, snat_session_t ** p_s0)
 672 {
 673   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 674                        next0, thread_index, p_s0, 0);
 675   snat_session_t *s0 = *p_s0;
 676   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
 677     {
 678       /* Accounting */
 679       nat44_session_update_counters (s0, now,
 680                                      vlib_buffer_length_in_chain
 681                                      (sm->vlib_main, b0), thread_index);
 682       /* Per-user LRU list maintenance */
 683       nat44_session_update_lru (sm, s0, thread_index);
 684     }
 685   return next0;
 686 }
 687
 688 static int
 689 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 690                              vlib_buffer_t * b,
 691                              ip4_header_t * ip, u32 rx_fib_index)
 692 {
 693   clib_bihash_kv_8_8_t kv, value;
 694   snat_static_mapping_t *m;
 695   snat_session_key_t m_key;
 696   u32 old_addr, new_addr;
 697   ip_csum_t sum;
 698
 699   m_key.addr = ip->dst_address;
 700   m_key.port = 0;
 701   m_key.protocol = 0;
 702   m_key.fib_index = 0;
 703   kv.key = m_key.as_u64;
 704   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 705     return 1;
 706
 707   m = pool_elt_at_index (sm->static_mappings, value.value);
 708
 709   old_addr = ip->dst_address.as_u32;
 710   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 711   sum = ip->checksum;
 712   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 713   ip->checksum = ip_csum_fold (sum);
 714
 715   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 716   return 0;
 717 }
 718
 719 VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 720                                  vlib_node_runtime_t * node,
 721                                  vlib_frame_t * frame)
 722 {
 723   u32 n_left_from, *from, *to_next;
 724   snat_out2in_next_t next_index;
 725   u32 pkts_processed = 0;
 726   snat_main_t *sm = &snat_main;
 727   f64 now = vlib_time_now (vm);
 728   u32 thread_index = vm->thread_index;
 729   u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
 730     0, fragments = 0;
 731
 732   from = vlib_frame_vector_args (frame);
 733   n_left_from = frame->n_vectors;
 734   next_index = node->cached_next_index;
 735
 736   while (n_left_from > 0)
 737     {
 738       u32 n_left_to_next;
 739
 740       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 741
 742       while (n_left_from >= 4 && n_left_to_next >= 2)
 743         {
 744           u32 bi0, bi1;
 745           vlib_buffer_t *b0, *b1;
 746           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 747           u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 748           u32 sw_if_index0, sw_if_index1;
 749           ip4_header_t *ip0, *ip1;
 750           ip_csum_t sum0, sum1;
 751           u32 new_addr0, old_addr0;
 752           u16 new_port0, old_port0;
 753           u32 new_addr1, old_addr1;
 754           u16 new_port1, old_port1;
 755           udp_header_t *udp0, *udp1;
 756           tcp_header_t *tcp0, *tcp1;
 757           icmp46_header_t *icmp0, *icmp1;
 758           snat_session_key_t key0, key1, sm0, sm1;
 759           u32 rx_fib_index0, rx_fib_index1;
 760           u32 proto0, proto1;
 761           snat_session_t *s0 = 0, *s1 = 0;
 762           clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
 763           u8 identity_nat0, identity_nat1;
 764
 765           /* Prefetch next iteration. */
 766           {
 767             vlib_buffer_t *p2, *p3;
 768
 769             p2 = vlib_get_buffer (vm, from[2]);
 770             p3 = vlib_get_buffer (vm, from[3]);
 771
 772             vlib_prefetch_buffer_header (p2, LOAD);
 773             vlib_prefetch_buffer_header (p3, LOAD);
 774
 775             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 776             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 777           }
 778
 779           /* speculatively enqueue b0 and b1 to the current next frame */
 780           to_next[0] = bi0 = from[0];
 781           to_next[1] = bi1 = from[1];
 782           from += 2;
 783           to_next += 2;
 784           n_left_from -= 2;
 785           n_left_to_next -= 2;
 786
 787           b0 = vlib_get_buffer (vm, bi0);
 788           b1 = vlib_get_buffer (vm, bi1);
 789
 790           vnet_buffer (b0)->snat.flags = 0;
 791           vnet_buffer (b1)->snat.flags = 0;
 792
 793           ip0 = vlib_buffer_get_current (b0);
 794           udp0 = ip4_next_header (ip0);
 795           tcp0 = (tcp_header_t *) udp0;
 796           icmp0 = (icmp46_header_t *) udp0;
 797
 798           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 799           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 800                                    sw_if_index0);
 801
 802           if (PREDICT_FALSE (ip0->ttl == 1))
 803             {
 804               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 805               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 806                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 807                                            0);
 808               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 809               goto trace0;
 810             }
 811
 812           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 813
 814           if (PREDICT_FALSE (proto0 == ~0))
 815             {
 816               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 817                 {
 818                   if (!sm->forwarding_enabled)
 819                     {
 820                       b0->error =
 821                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 822                       next0 = SNAT_OUT2IN_NEXT_DROP;
 823                     }
 824                 }
 825               other_packets++;
 826               goto trace0;
 827             }
 828
 829           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 830             {
 831               next0 = icmp_out2in_slow_path
 832                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 833                  next0, now, thread_index, &s0);
 834               icmp_packets++;
 835               goto trace0;
 836             }
 837
 838           key0.addr = ip0->dst_address;
 839           key0.port = vnet_buffer (b0)->ip.reass.l4_dst_port;
 840           key0.protocol = proto0;
 841           key0.fib_index = rx_fib_index0;
 842
 843           kv0.key = key0.as_u64;
 844
 845           if (clib_bihash_search_8_8
 846               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
 847             {
 848               /* Try to match static mapping by external address and port,
 849                  destination address and port in packet */
 850               if (snat_static_mapping_match
 851                   (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
 852                 {
 853                   /*
 854                    * Send DHCP packets to the ipv4 stack, or we won't
 855                    * be able to use dhcp client on the outside interface
 856                    */
 857                   if (PREDICT_FALSE
 858                       (proto0 == SNAT_PROTOCOL_UDP
 859                        && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
 860                            clib_host_to_net_u16
 861                            (UDP_DST_PORT_dhcp_to_client))))
 862                     {
 863                       vnet_feature_next (&next0, b0);
 864                       goto trace0;
 865                     }
 866
 867                   if (!sm->forwarding_enabled)
 868                     {
 869                       b0->error =
 870                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 871                       next0 = SNAT_OUT2IN_NEXT_DROP;
 872                     }
 873                   goto trace0;
 874                 }
 875
 876               if (PREDICT_FALSE (identity_nat0))
 877                 goto trace0;
 878
 879               /* Create session initiated by host from external network */
 880               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
 881                                                       thread_index, now);
 882               if (!s0)
 883                 {
 884                   next0 = SNAT_OUT2IN_NEXT_DROP;
 885                   goto trace0;
 886                 }
 887             }
 888           else
 889             s0 =
 890               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 891                                  value0.value);
 892
 893           old_addr0 = ip0->dst_address.as_u32;
 894           ip0->dst_address = s0->in2out.addr;
 895           new_addr0 = ip0->dst_address.as_u32;
 896           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 897
 898           sum0 = ip0->checksum;
 899           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 900                                  ip4_header_t,
 901                                  dst_address /* changed member */ );
 902           ip0->checksum = ip_csum_fold (sum0);
 903
 904           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 905             {
 906               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 907                 {
 908                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 909                   new_port0 = udp0->dst_port = s0->in2out.port;
 910                   sum0 = tcp0->checksum;
 911                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 912                                          ip4_header_t,
 913                                          dst_address /* changed member */ );
 914
 915                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
 916                                          ip4_header_t /* cheat */ ,
 917                                          length /* changed member */ );
 918                   tcp0->checksum = ip_csum_fold (sum0);
 919                 }
 920               tcp_packets++;
 921             }
 922           else
 923             {
 924               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 925                 {
 926                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 927                   new_port0 = udp0->dst_port = s0->in2out.port;
 928                   if (PREDICT_FALSE (udp0->checksum))
 929                     {
 930                       sum0 = udp0->checksum;
 931                       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address      /* changed member */
 932                         );
 933                       sum0 =
 934                         ip_csum_update (sum0, old_port0, new_port0,
 935                                         ip4_header_t /* cheat */ ,
 936                                         length /* changed member */ );
 937                       udp0->checksum = ip_csum_fold (sum0);
 938                     }
 939                 }
 940               udp_packets++;
 941             }
 942
 943           /* Accounting */
 944           nat44_session_update_counters (s0, now,
 945                                          vlib_buffer_length_in_chain (vm, b0),
 946                                          thread_index);
 947           /* Per-user LRU list maintenance */
 948           nat44_session_update_lru (sm, s0, thread_index);
 949         trace0:
 950
 951           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 952                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 953             {
 954               snat_out2in_trace_t *t =
 955                 vlib_add_trace (vm, node, b0, sizeof (*t));
 956               t->sw_if_index = sw_if_index0;
 957               t->next_index = next0;
 958               t->session_index = ~0;
 959               if (s0)
 960                 t->session_index =
 961                   s0 - sm->per_thread_data[thread_index].sessions;
 962             }
 963
 964           pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
 965
 966
 967           ip1 = vlib_buffer_get_current (b1);
 968           udp1 = ip4_next_header (ip1);
 969           tcp1 = (tcp_header_t *) udp1;
 970           icmp1 = (icmp46_header_t *) udp1;
 971
 972           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 973           rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 974                                    sw_if_index1);
 975
 976           if (PREDICT_FALSE (ip1->ttl == 1))
 977             {
 978               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 979               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 980                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 981                                            0);
 982               next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 983               goto trace1;
 984             }
 985
 986           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 987
 988           if (PREDICT_FALSE (proto1 == ~0))
 989             {
 990               if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
 991                 {
 992                   if (!sm->forwarding_enabled)
 993                     {
 994                       b1->error =
 995                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 996                       next1 = SNAT_OUT2IN_NEXT_DROP;
 997                     }
 998                 }
 999               other_packets++;
1000               goto trace1;
1001             }
1002
1003           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
1004             {
1005               next1 = icmp_out2in_slow_path
1006                 (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
1007                  next1, now, thread_index, &s1);
1008               icmp_packets++;
1009               goto trace1;
1010             }
1011
1012           key1.addr = ip1->dst_address;
1013           key1.port = vnet_buffer (b1)->ip.reass.l4_dst_port;
1014           key1.protocol = proto1;
1015           key1.fib_index = rx_fib_index1;
1016
1017           kv1.key = key1.as_u64;
1018
1019           if (clib_bihash_search_8_8
1020               (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
1021             {
1022               /* Try to match static mapping by external address and port,
1023                  destination address and port in packet */
1024               if (snat_static_mapping_match
1025                   (sm, key1, &sm1, 1, 0, 0, 0, 0, &identity_nat1))
1026                 {
1027                   /*
1028                    * Send DHCP packets to the ipv4 stack, or we won't
1029                    * be able to use dhcp client on the outside interface
1030                    */
1031                   if (PREDICT_FALSE
1032                       (proto1 == SNAT_PROTOCOL_UDP
1033                        && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
1034                            clib_host_to_net_u16
1035                            (UDP_DST_PORT_dhcp_to_client))))
1036                     {
1037                       vnet_feature_next (&next1, b1);
1038                       goto trace1;
1039                     }
1040
1041                   if (!sm->forwarding_enabled)
1042                     {
1043                       b1->error =
1044                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1045                       next1 = SNAT_OUT2IN_NEXT_DROP;
1046                     }
1047                   goto trace1;
1048                 }
1049
1050               if (PREDICT_FALSE (identity_nat1))
1051                 goto trace1;
1052
1053               /* Create session initiated by host from external network */
1054               s1 = create_session_for_static_mapping (sm, b1, sm1, key1, node,
1055                                                       thread_index, now);
1056               if (!s1)
1057                 {
1058                   next1 = SNAT_OUT2IN_NEXT_DROP;
1059                   goto trace1;
1060                 }
1061             }
1062           else
1063             s1 =
1064               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1065                                  value1.value);
1066
1067           old_addr1 = ip1->dst_address.as_u32;
1068           ip1->dst_address = s1->in2out.addr;
1069           new_addr1 = ip1->dst_address.as_u32;
1070           vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1071
1072           sum1 = ip1->checksum;
1073           sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1074                                  ip4_header_t,
1075                                  dst_address /* changed member */ );
1076           ip1->checksum = ip_csum_fold (sum1);
1077
1078           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
1079             {
1080               if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1081                 {
1082                   old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1083                   new_port1 = udp1->dst_port = s1->in2out.port;
1084
1085                   sum1 = tcp1->checksum;
1086                   sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1087                                          ip4_header_t,
1088                                          dst_address /* changed member */ );
1089
1090                   sum1 = ip_csum_update (sum1, old_port1, new_port1,
1091                                          ip4_header_t /* cheat */ ,
1092                                          length /* changed member */ );
1093                   tcp1->checksum = ip_csum_fold (sum1);
1094                 }
1095               tcp_packets++;
1096             }
1097           else
1098             {
1099               if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1100                 {
1101                   old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1102                   new_port1 = udp1->dst_port = s1->in2out.port;
1103                   if (PREDICT_FALSE (udp1->checksum))
1104                     {
1105
1106                       sum1 = udp1->checksum;
1107                       sum1 =
1108                         ip_csum_update (sum1, old_addr1, new_addr1,
1109                                         ip4_header_t,
1110                                         dst_address /* changed member */ );
1111                       sum1 =
1112                         ip_csum_update (sum1, old_port1, new_port1,
1113                                         ip4_header_t /* cheat */ ,
1114                                         length /* changed member */ );
1115                       udp1->checksum = ip_csum_fold (sum1);
1116                     }
1117                 }
1118               udp_packets++;
1119             }
1120
1121           /* Accounting */
1122           nat44_session_update_counters (s1, now,
1123                                          vlib_buffer_length_in_chain (vm, b1),
1124                                          thread_index);
1125           /* Per-user LRU list maintenance */
1126           nat44_session_update_lru (sm, s1, thread_index);
1127         trace1:
1128
1129           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1130                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1131             {
1132               snat_out2in_trace_t *t =
1133                 vlib_add_trace (vm, node, b1, sizeof (*t));
1134               t->sw_if_index = sw_if_index1;
1135               t->next_index = next1;
1136               t->session_index = ~0;
1137               if (s1)
1138                 t->session_index =
1139                   s1 - sm->per_thread_data[thread_index].sessions;
1140             }
1141
1142           pkts_processed += next1 == SNAT_OUT2IN_NEXT_LOOKUP;
1143
1144           /* verify speculative enqueues, maybe switch current next frame */
1145           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
1146                                            to_next, n_left_to_next,
1147                                            bi0, bi1, next0, next1);
1148         }
1149
1150       while (n_left_from > 0 && n_left_to_next > 0)
1151         {
1152           u32 bi0;
1153           vlib_buffer_t *b0;
1154           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1155           u32 sw_if_index0;
1156           ip4_header_t *ip0;
1157           ip_csum_t sum0;
1158           u32 new_addr0, old_addr0;
1159           u16 new_port0, old_port0;
1160           udp_header_t *udp0;
1161           tcp_header_t *tcp0;
1162           icmp46_header_t *icmp0;
1163           snat_session_key_t key0, sm0;
1164           u32 rx_fib_index0;
1165           u32 proto0;
1166           snat_session_t *s0 = 0;
1167           clib_bihash_kv_8_8_t kv0, value0;
1168           u8 identity_nat0;
1169
1170           /* speculatively enqueue b0 to the current next frame */
1171           bi0 = from[0];
1172           to_next[0] = bi0;
1173           from += 1;
1174           to_next += 1;
1175           n_left_from -= 1;
1176           n_left_to_next -= 1;
1177
1178           b0 = vlib_get_buffer (vm, bi0);
1179
1180           vnet_buffer (b0)->snat.flags = 0;
1181
1182           ip0 = vlib_buffer_get_current (b0);
1183           udp0 = ip4_next_header (ip0);
1184           tcp0 = (tcp_header_t *) udp0;
1185           icmp0 = (icmp46_header_t *) udp0;
1186
1187           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1188           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1189                                    sw_if_index0);
1190
1191           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1192
1193           if (PREDICT_FALSE (proto0 == ~0))
1194             {
1195               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1196                 {
1197                   if (!sm->forwarding_enabled)
1198                     {
1199                       b0->error =
1200                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1201                       next0 = SNAT_OUT2IN_NEXT_DROP;
1202                     }
1203                 }
1204               other_packets++;
1205               goto trace00;
1206             }
1207
1208           if (PREDICT_FALSE (ip0->ttl == 1))
1209             {
1210               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1211               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1212                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1213                                            0);
1214               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1215               goto trace00;
1216             }
1217
1218           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1219             {
1220               next0 = icmp_out2in_slow_path
1221                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1222                  next0, now, thread_index, &s0);
1223               icmp_packets++;
1224               goto trace00;
1225             }
1226
1227           key0.addr = ip0->dst_address;
1228           key0.port = vnet_buffer (b0)->ip.reass.l4_dst_port;
1229           key0.protocol = proto0;
1230           key0.fib_index = rx_fib_index0;
1231
1232           kv0.key = key0.as_u64;
1233
1234           if (clib_bihash_search_8_8
1235               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
1236             {
1237               /* Try to match static mapping by external address and port,
1238                  destination address and port in packet */
1239               if (snat_static_mapping_match
1240                   (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
1241                 {
1242                   /*
1243                    * Send DHCP packets to the ipv4 stack, or we won't
1244                    * be able to use dhcp client on the outside interface
1245                    */
1246                   if (PREDICT_FALSE
1247                       (proto0 == SNAT_PROTOCOL_UDP
1248                        && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
1249                            clib_host_to_net_u16
1250                            (UDP_DST_PORT_dhcp_to_client))))
1251                     {
1252                       vnet_feature_next (&next0, b0);
1253                       goto trace00;
1254                     }
1255
1256                   if (!sm->forwarding_enabled)
1257                     {
1258                       b0->error =
1259                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1260                       next0 = SNAT_OUT2IN_NEXT_DROP;
1261                     }
1262                   goto trace00;
1263                 }
1264
1265               if (PREDICT_FALSE (identity_nat0))
1266                 goto trace00;
1267
1268               /* Create session initiated by host from external network */
1269               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
1270                                                       thread_index, now);
1271               if (!s0)
1272                 {
1273                   next0 = SNAT_OUT2IN_NEXT_DROP;
1274                   goto trace00;
1275                 }
1276             }
1277           else
1278             s0 =
1279               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1280                                  value0.value);
1281
1282           old_addr0 = ip0->dst_address.as_u32;
1283           ip0->dst_address = s0->in2out.addr;
1284           new_addr0 = ip0->dst_address.as_u32;
1285           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1286
1287           sum0 = ip0->checksum;
1288           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1289                                  ip4_header_t,
1290                                  dst_address /* changed member */ );
1291           ip0->checksum = ip_csum_fold (sum0);
1292
1293           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1294             {
1295               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1296                 {
1297                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1298                   new_port0 = udp0->dst_port = s0->in2out.port;
1299
1300                   sum0 = tcp0->checksum;
1301                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1302                                          ip4_header_t,
1303                                          dst_address /* changed member */ );
1304
1305                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1306                                          ip4_header_t /* cheat */ ,
1307                                          length /* changed member */ );
1308                   tcp0->checksum = ip_csum_fold (sum0);
1309                 }
1310               tcp_packets++;
1311             }
1312           else
1313             {
1314               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1315                 {
1316                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1317                   new_port0 = udp0->dst_port = s0->in2out.port;
1318                   if (PREDICT_FALSE (udp0->checksum))
1319                     {
1320                       sum0 = udp0->checksum;
1321                       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address      /* changed member */
1322                         );
1323                       sum0 =
1324                         ip_csum_update (sum0, old_port0, new_port0,
1325                                         ip4_header_t /* cheat */ ,
1326                                         length /* changed member */ );
1327                       udp0->checksum = ip_csum_fold (sum0);
1328                     }
1329                 }
1330               udp_packets++;
1331             }
1332
1333           /* Accounting */
1334           nat44_session_update_counters (s0, now,
1335                                          vlib_buffer_length_in_chain (vm, b0),
1336                                          thread_index);
1337           /* Per-user LRU list maintenance */
1338           nat44_session_update_lru (sm, s0, thread_index);
1339         trace00:
1340
1341           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1342                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1343             {
1344               snat_out2in_trace_t *t =
1345                 vlib_add_trace (vm, node, b0, sizeof (*t));
1346               t->sw_if_index = sw_if_index0;
1347               t->next_index = next0;
1348               t->session_index = ~0;
1349               if (s0)
1350                 t->session_index =
1351                   s0 - sm->per_thread_data[thread_index].sessions;
1352             }
1353
1354           pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
1355
1356           /* verify speculative enqueue, maybe switch current next frame */
1357           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1358                                            to_next, n_left_to_next,
1359                                            bi0, next0);
1360         }
1361
1362       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1363     }
1364
1365   vlib_node_increment_counter (vm, sm->out2in_node_index,
1366                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1367                                pkts_processed);
1368   vlib_node_increment_counter (vm, sm->out2in_node_index,
1369                                SNAT_OUT2IN_ERROR_TCP_PACKETS, tcp_packets);
1370   vlib_node_increment_counter (vm, sm->out2in_node_index,
1371                                SNAT_OUT2IN_ERROR_UDP_PACKETS, udp_packets);
1372   vlib_node_increment_counter (vm, sm->out2in_node_index,
1373                                SNAT_OUT2IN_ERROR_ICMP_PACKETS, icmp_packets);
1374   vlib_node_increment_counter (vm, sm->out2in_node_index,
1375                                SNAT_OUT2IN_ERROR_OTHER_PACKETS,
1376                                other_packets);
1377   vlib_node_increment_counter (vm, sm->out2in_node_index,
1378                                SNAT_OUT2IN_ERROR_FRAGMENTS, fragments);
1379
1380   return frame->n_vectors;
1381 }
1382
1383 /* *INDENT-OFF* */
1384 VLIB_REGISTER_NODE (snat_out2in_node) = {
1385   .name = "nat44-out2in",
1386   .vector_size = sizeof (u32),
1387   .format_trace = format_snat_out2in_trace,
1388   .type = VLIB_NODE_TYPE_INTERNAL,
1389
1390   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1391   .error_strings = snat_out2in_error_strings,
1392
1393   .runtime_data_bytes = sizeof (snat_runtime_t),
1394
1395   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1396
1397   /* edit / add dispositions here */
1398   .next_nodes = {
1399     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1400     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1401     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1402   },
1403 };
1404 /* *INDENT-ON* */
1405
1406 VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
1407                                       vlib_node_runtime_t * node,
1408                                       vlib_frame_t * frame)
1409 {
1410   u32 n_left_from, *from, *to_next;
1411   snat_out2in_next_t next_index;
1412   u32 pkts_processed = 0;
1413   snat_main_t *sm = &snat_main;
1414
1415   from = vlib_frame_vector_args (frame);
1416   n_left_from = frame->n_vectors;
1417   next_index = node->cached_next_index;
1418
1419   while (n_left_from > 0)
1420     {
1421       u32 n_left_to_next;
1422
1423       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1424
1425       while (n_left_from > 0 && n_left_to_next > 0)
1426         {
1427           u32 bi0;
1428           vlib_buffer_t *b0;
1429           u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1430           u32 sw_if_index0;
1431           ip4_header_t *ip0;
1432           ip_csum_t sum0;
1433           u32 new_addr0, old_addr0;
1434           u16 new_port0, old_port0;
1435           udp_header_t *udp0;
1436           tcp_header_t *tcp0;
1437           icmp46_header_t *icmp0;
1438           snat_session_key_t key0, sm0;
1439           u32 proto0;
1440           u32 rx_fib_index0;
1441
1442           /* speculatively enqueue b0 to the current next frame */
1443           bi0 = from[0];
1444           to_next[0] = bi0;
1445           from += 1;
1446           to_next += 1;
1447           n_left_from -= 1;
1448           n_left_to_next -= 1;
1449
1450           b0 = vlib_get_buffer (vm, bi0);
1451
1452           ip0 = vlib_buffer_get_current (b0);
1453           udp0 = ip4_next_header (ip0);
1454           tcp0 = (tcp_header_t *) udp0;
1455           icmp0 = (icmp46_header_t *) udp0;
1456
1457           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1458           rx_fib_index0 =
1459             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1460
1461           vnet_feature_next (&next0, b0);
1462
1463           if (PREDICT_FALSE (ip0->ttl == 1))
1464             {
1465               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1466               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1467                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1468                                            0);
1469               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1470               goto trace00;
1471             }
1472
1473           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1474
1475           if (PREDICT_FALSE (proto0 == ~0))
1476             goto trace00;
1477
1478           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1479             {
1480               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1481                                    rx_fib_index0, node, next0, ~0, 0, 0);
1482               goto trace00;
1483             }
1484
1485           key0.addr = ip0->dst_address;
1486           key0.port = udp0->dst_port;
1487           key0.fib_index = rx_fib_index0;
1488
1489           if (snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0, 0))
1490             {
1491               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1492               goto trace00;
1493             }
1494
1495           new_addr0 = sm0.addr.as_u32;
1496           new_port0 = sm0.port;
1497           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
1498           old_addr0 = ip0->dst_address.as_u32;
1499           ip0->dst_address.as_u32 = new_addr0;
1500
1501           sum0 = ip0->checksum;
1502           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1503                                  ip4_header_t,
1504                                  dst_address /* changed member */ );
1505           ip0->checksum = ip_csum_fold (sum0);
1506
1507           if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1508             {
1509               old_port0 = udp0->dst_port;
1510               udp0->dst_port = new_port0;
1511
1512               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1513                 {
1514                   sum0 = tcp0->checksum;
1515                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1516                                          ip4_header_t,
1517                                          dst_address /* changed member */ );
1518                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1519                                          ip4_header_t /* cheat */ ,
1520                                          length /* changed member */ );
1521                   tcp0->checksum = ip_csum_fold (sum0);
1522                 }
1523               else if (udp0->checksum)
1524                 {
1525                   sum0 = udp0->checksum;
1526                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1527                                          ip4_header_t,
1528                                          dst_address /* changed member */ );
1529                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1530                                          ip4_header_t /* cheat */ ,
1531                                          length /* changed member */ );
1532                   udp0->checksum = ip_csum_fold (sum0);
1533                 }
1534             }
1535           else
1536             {
1537               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1538                 {
1539                   sum0 = tcp0->checksum;
1540                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1541                                          ip4_header_t,
1542                                          dst_address /* changed member */ );
1543                   tcp0->checksum = ip_csum_fold (sum0);
1544                 }
1545               else if (udp0->checksum)
1546                 {
1547                   sum0 = udp0->checksum;
1548                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1549                                          ip4_header_t,
1550                                          dst_address /* changed member */ );
1551                   udp0->checksum = ip_csum_fold (sum0);
1552                 }
1553             }
1554
1555         trace00:
1556
1557           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1558                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1559             {
1560               snat_out2in_trace_t *t =
1561                 vlib_add_trace (vm, node, b0, sizeof (*t));
1562               t->sw_if_index = sw_if_index0;
1563               t->next_index = next0;
1564             }
1565
1566           pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1567
1568           /* verify speculative enqueue, maybe switch current next frame */
1569           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1570                                            to_next, n_left_to_next,
1571                                            bi0, next0);
1572         }
1573
1574       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1575     }
1576
1577   vlib_node_increment_counter (vm, sm->out2in_fast_node_index,
1578                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1579                                pkts_processed);
1580   return frame->n_vectors;
1581 }
1582
1583 /* *INDENT-OFF* */
1584 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1585   .name = "nat44-out2in-fast",
1586   .vector_size = sizeof (u32),
1587   .format_trace = format_snat_out2in_fast_trace,
1588   .type = VLIB_NODE_TYPE_INTERNAL,
1589
1590   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1591   .error_strings = snat_out2in_error_strings,
1592
1593   .runtime_data_bytes = sizeof (snat_runtime_t),
1594
1595   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1596
1597   /* edit / add dispositions here */
1598   .next_nodes = {
1599     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1600     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1601     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1602   },
1603 };
1604 /* *INDENT-ON* */
1605
1606 /*
1607  * fd.io coding-style-patch-verification: ON
1608  *
1609  * Local Variables:
1610  * eval: (c-set-style "gnu")
1611  * End:
1612  */