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   if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
 192     {
 193       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
 194       nat_elog_notice ("maximum sessions exceeded");
 195       return 0;
 196     }
 197
 198   ip0 = vlib_buffer_get_current (b0);
 199   udp0 = ip4_next_header (ip0);
 200
 201   u =
 202     nat_user_get_or_create (sm, &in2out.addr, in2out.fib_index, thread_index);
 203   if (!u)
 204     {
 205       nat_elog_warn ("create NAT user failed");
 206       return 0;
 207     }
 208
 209   s = nat_session_alloc_or_recycle (sm, u, thread_index, now);
 210   if (!s)
 211     {
 212       nat44_delete_user_with_no_session (sm, u, thread_index);
 213       nat_elog_warn ("create NAT session failed");
 214       return 0;
 215     }
 216
 217   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 218   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
 219   s->ext_host_port = udp0->src_port;
 220   user_session_increment (sm, u, 1 /* static */ );
 221   s->in2out = in2out;
 222   s->out2in = out2in;
 223   s->in2out.protocol = out2in.protocol;
 224
 225   /* Add to translation hashes */
 226   ctx0.now = now;
 227   ctx0.thread_index = thread_index;
 228   kv0.key = s->in2out.as_u64;
 229   kv0.value = s - sm->per_thread_data[thread_index].sessions;
 230   if (clib_bihash_add_or_overwrite_stale_8_8
 231       (&sm->per_thread_data[thread_index].in2out, &kv0,
 232        nat44_i2o_is_idle_session_cb, &ctx0))
 233     nat_elog_notice ("in2out key add failed");
 234
 235   kv0.key = s->out2in.as_u64;
 236
 237   if (clib_bihash_add_or_overwrite_stale_8_8
 238       (&sm->per_thread_data[thread_index].out2in, &kv0,
 239        nat44_o2i_is_idle_session_cb, &ctx0))
 240     nat_elog_notice ("out2in key add failed");
 241
 242   /* log NAT event */
 243   snat_ipfix_logging_nat44_ses_create (thread_index,
 244                                        s->in2out.addr.as_u32,
 245                                        s->out2in.addr.as_u32,
 246                                        s->in2out.protocol,
 247                                        s->in2out.port,
 248                                        s->out2in.port, s->in2out.fib_index);
 249
 250   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
 251                            &s->in2out.addr, s->in2out.port, &s->out2in.addr,
 252                            s->out2in.port, s->in2out.protocol);
 253
 254   nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
 255                s->out2in.port, &s->ext_host_addr, s->ext_host_port,
 256                &s->ext_host_nat_addr, s->ext_host_nat_port,
 257                s->in2out.protocol, s->in2out.fib_index, s->flags,
 258                thread_index, 0);
 259
 260   return s;
 261 }
 262
 263 #ifndef CLIB_MARCH_VARIANT
 264 static_always_inline
 265   snat_out2in_error_t icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
 266                                     snat_session_key_t * p_key0)
 267 {
 268   icmp46_header_t *icmp0;
 269   snat_session_key_t key0;
 270   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 271   ip4_header_t *inner_ip0;
 272   void *l4_header = 0;
 273   icmp46_header_t *inner_icmp0;
 274
 275   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 276   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 277
 278   if (!icmp_type_is_error_message
 279       (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
 280     {
 281       key0.protocol = SNAT_PROTOCOL_ICMP;
 282       key0.addr = ip0->dst_address;
 283       key0.port = vnet_buffer (b)->ip.reass.l4_src_port;        // TODO should this be dst port?
 284     }
 285   else
 286     {
 287       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 288       l4_header = ip4_next_header (inner_ip0);
 289       key0.protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
 290       key0.addr = inner_ip0->src_address;
 291       switch (key0.protocol)
 292         {
 293         case SNAT_PROTOCOL_ICMP:
 294           inner_icmp0 = (icmp46_header_t *) l4_header;
 295           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 296           key0.port = inner_echo0->identifier;
 297           break;
 298         case SNAT_PROTOCOL_UDP:
 299         case SNAT_PROTOCOL_TCP:
 300           key0.port = ((tcp_udp_header_t *) l4_header)->src_port;
 301           break;
 302         default:
 303           return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
 304         }
 305     }
 306   *p_key0 = key0;
 307   return -1;                    /* success */
 308 }
 309
 310 /**
 311  * Get address and port values to be used for ICMP packet translation
 312  * and create session if needed
 313  *
 314  * @param[in,out] sm             NAT main
 315  * @param[in,out] node           NAT node runtime
 316  * @param[in] thread_index       thread index
 317  * @param[in,out] b0             buffer containing packet to be translated
 318  * @param[in,out] ip0            ip header
 319  * @param[out] p_proto           protocol used for matching
 320  * @param[out] p_value           address and port after NAT translation
 321  * @param[out] p_dont_translate  if packet should not be translated
 322  * @param d                      optional parameter
 323  * @param e                      optional parameter
 324  */
 325 u32
 326 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 327                         u32 thread_index, vlib_buffer_t * b0,
 328                         ip4_header_t * ip0, u8 * p_proto,
 329                         snat_session_key_t * p_value,
 330                         u8 * p_dont_translate, void *d, void *e)
 331 {
 332   u32 sw_if_index0;
 333   u32 rx_fib_index0;
 334   snat_session_key_t key0;
 335   snat_session_key_t sm0;
 336   snat_session_t *s0 = 0;
 337   u8 dont_translate = 0;
 338   clib_bihash_kv_8_8_t kv0, value0;
 339   u8 is_addr_only;
 340   u32 next0 = ~0;
 341   int err;
 342   u8 identity_nat;
 343
 344   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 345   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 346
 347   key0.protocol = 0;
 348
 349   err = icmp_get_key (b0, ip0, &key0);
 350   if (err != -1)
 351     {
 352       b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 353       next0 = SNAT_OUT2IN_NEXT_DROP;
 354       goto out;
 355     }
 356   key0.fib_index = rx_fib_index0;
 357
 358   kv0.key = key0.as_u64;
 359
 360   if (clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].out2in, &kv0,
 361                               &value0))
 362     {
 363       /* Try to match static mapping by external address and port,
 364          destination address and port in packet */
 365       if (snat_static_mapping_match
 366           (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0, &identity_nat))
 367         {
 368           if (!sm->forwarding_enabled)
 369             {
 370               /* Don't NAT packet aimed at the intfc address */
 371               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 372                                                     ip0->dst_address.as_u32)))
 373                 {
 374                   dont_translate = 1;
 375                   goto out;
 376                 }
 377               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 378               next0 = SNAT_OUT2IN_NEXT_DROP;
 379               goto out;
 380             }
 381           else
 382             {
 383               dont_translate = 1;
 384               goto out;
 385             }
 386         }
 387
 388       if (PREDICT_FALSE
 389           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 390            ICMP4_echo_reply
 391            && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 392                ICMP4_echo_request || !is_addr_only)))
 393         {
 394           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 395           next0 = SNAT_OUT2IN_NEXT_DROP;
 396           goto out;
 397         }
 398
 399       if (PREDICT_FALSE (identity_nat))
 400         {
 401           dont_translate = 1;
 402           goto out;
 403         }
 404       /* Create session initiated by host from external network */
 405       s0 = create_session_for_static_mapping (sm, b0, sm0, key0,
 406                                               node, thread_index,
 407                                               vlib_time_now (sm->vlib_main));
 408
 409       if (!s0)
 410         {
 411           next0 = SNAT_OUT2IN_NEXT_DROP;
 412           goto out;
 413         }
 414     }
 415   else
 416     {
 417       if (PREDICT_FALSE
 418           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 419            ICMP4_echo_reply
 420            && vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 421            ICMP4_echo_request
 422            && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 423                                            reass.icmp_type_or_tcp_flags)))
 424         {
 425           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 426           next0 = SNAT_OUT2IN_NEXT_DROP;
 427           goto out;
 428         }
 429
 430       s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 431                               value0.value);
 432     }
 433
 434 out:
 435   *p_proto = key0.protocol;
 436   if (s0)
 437     *p_value = s0->in2out;
 438   *p_dont_translate = dont_translate;
 439   if (d)
 440     *(snat_session_t **) d = s0;
 441   return next0;
 442 }
 443 #endif
 444
 445 #ifndef CLIB_MARCH_VARIANT
 446 /**
 447  * Get address and port values to be used for ICMP packet translation
 448  *
 449  * @param[in] sm                 NAT main
 450  * @param[in,out] node           NAT node runtime
 451  * @param[in] thread_index       thread index
 452  * @param[in,out] b0             buffer containing packet to be translated
 453  * @param[in,out] ip0            ip header
 454  * @param[out] p_proto           protocol used for matching
 455  * @param[out] p_value           address and port after NAT translation
 456  * @param[out] p_dont_translate  if packet should not be translated
 457  * @param d                      optional parameter
 458  * @param e                      optional parameter
 459  */
 460 u32
 461 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
 462                         u32 thread_index, vlib_buffer_t * b0,
 463                         ip4_header_t * ip0, u8 * p_proto,
 464                         snat_session_key_t * p_value,
 465                         u8 * p_dont_translate, void *d, void *e)
 466 {
 467   u32 sw_if_index0;
 468   u32 rx_fib_index0;
 469   snat_session_key_t key0;
 470   snat_session_key_t sm0;
 471   u8 dont_translate = 0;
 472   u8 is_addr_only;
 473   u32 next0 = ~0;
 474   int err;
 475
 476   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 477   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 478
 479   err = icmp_get_key (b0, ip0, &key0);
 480   if (err != -1)
 481     {
 482       b0->error = node->errors[err];
 483       next0 = SNAT_OUT2IN_NEXT_DROP;
 484       goto out2;
 485     }
 486   key0.fib_index = rx_fib_index0;
 487
 488   if (snat_static_mapping_match
 489       (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0, 0))
 490     {
 491       /* Don't NAT packet aimed at the intfc address */
 492       if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
 493         {
 494           dont_translate = 1;
 495           goto out;
 496         }
 497       b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 498       next0 = SNAT_OUT2IN_NEXT_DROP;
 499       goto out;
 500     }
 501
 502   if (PREDICT_FALSE
 503       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
 504        && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 505            ICMP4_echo_request || !is_addr_only)
 506        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 507                                        reass.icmp_type_or_tcp_flags)))
 508     {
 509       b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 510       next0 = SNAT_OUT2IN_NEXT_DROP;
 511       goto out;
 512     }
 513
 514 out:
 515   *p_value = sm0;
 516 out2:
 517   *p_proto = key0.protocol;
 518   *p_dont_translate = dont_translate;
 519   return next0;
 520 }
 521 #endif
 522
 523 #ifndef CLIB_MARCH_VARIANT
 524 u32
 525 icmp_out2in (snat_main_t * sm,
 526              vlib_buffer_t * b0,
 527              ip4_header_t * ip0,
 528              icmp46_header_t * icmp0,
 529              u32 sw_if_index0,
 530              u32 rx_fib_index0,
 531              vlib_node_runtime_t * node,
 532              u32 next0, u32 thread_index, void *d, void *e)
 533 {
 534   snat_session_key_t sm0;
 535   u8 protocol;
 536   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 537   ip4_header_t *inner_ip0 = 0;
 538   void *l4_header = 0;
 539   icmp46_header_t *inner_icmp0;
 540   u8 dont_translate;
 541   u32 new_addr0, old_addr0;
 542   u16 old_id0, new_id0;
 543   ip_csum_t sum0;
 544   u16 checksum0;
 545   u32 next0_tmp;
 546
 547   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 548
 549   next0_tmp = sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0,
 550                                         &protocol, &sm0, &dont_translate, d,
 551                                         e);
 552   if (next0_tmp != ~0)
 553     next0 = next0_tmp;
 554   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
 555     goto out;
 556
 557   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 558     {
 559       sum0 = ip_incremental_checksum_buffer (sm->vlib_main, b0, (u8 *) icmp0 -
 560                                              (u8 *)
 561                                              vlib_buffer_get_current (b0),
 562                                              ntohs (ip0->length) -
 563                                              ip4_header_bytes (ip0), 0);
 564       checksum0 = ~ip_csum_fold (sum0);
 565       if (checksum0 != 0 && checksum0 != 0xffff)
 566         {
 567           next0 = SNAT_OUT2IN_NEXT_DROP;
 568           goto out;
 569         }
 570     }
 571
 572   old_addr0 = ip0->dst_address.as_u32;
 573   new_addr0 = ip0->dst_address.as_u32 = sm0.addr.as_u32;
 574   vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
 575
 576   sum0 = ip0->checksum;
 577   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 578                          dst_address /* changed member */ );
 579   ip0->checksum = ip_csum_fold (sum0);
 580
 581
 582   if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 583     {
 584       if (icmp0->checksum == 0)
 585         icmp0->checksum = 0xffff;
 586
 587       if (!icmp_type_is_error_message (icmp0->type))
 588         {
 589           new_id0 = sm0.port;
 590           if (PREDICT_FALSE (new_id0 != echo0->identifier))
 591             {
 592               old_id0 = echo0->identifier;
 593               new_id0 = sm0.port;
 594               echo0->identifier = new_id0;
 595
 596               sum0 = icmp0->checksum;
 597               sum0 =
 598                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 599                                 identifier /* changed member */ );
 600               icmp0->checksum = ip_csum_fold (sum0);
 601             }
 602         }
 603       else
 604         {
 605           inner_ip0 = (ip4_header_t *) (echo0 + 1);
 606           l4_header = ip4_next_header (inner_ip0);
 607
 608           if (!ip4_header_checksum_is_valid (inner_ip0))
 609             {
 610               next0 = SNAT_OUT2IN_NEXT_DROP;
 611               goto out;
 612             }
 613
 614           old_addr0 = inner_ip0->src_address.as_u32;
 615           inner_ip0->src_address = sm0.addr;
 616           new_addr0 = inner_ip0->src_address.as_u32;
 617
 618           sum0 = icmp0->checksum;
 619           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 620                                  src_address /* changed member */ );
 621           icmp0->checksum = ip_csum_fold (sum0);
 622
 623           switch (protocol)
 624             {
 625             case SNAT_PROTOCOL_ICMP:
 626               inner_icmp0 = (icmp46_header_t *) l4_header;
 627               inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 628
 629               old_id0 = inner_echo0->identifier;
 630               new_id0 = sm0.port;
 631               inner_echo0->identifier = new_id0;
 632
 633               sum0 = icmp0->checksum;
 634               sum0 =
 635                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 636                                 identifier);
 637               icmp0->checksum = ip_csum_fold (sum0);
 638               break;
 639             case SNAT_PROTOCOL_UDP:
 640             case SNAT_PROTOCOL_TCP:
 641               old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 642               new_id0 = sm0.port;
 643               ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 644
 645               sum0 = icmp0->checksum;
 646               sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 647                                      src_port);
 648               icmp0->checksum = ip_csum_fold (sum0);
 649               break;
 650             default:
 651               ASSERT (0);
 652             }
 653         }
 654     }
 655
 656 out:
 657   return next0;
 658 }
 659 #endif
 660
 661 static inline u32
 662 icmp_out2in_slow_path (snat_main_t * sm,
 663                        vlib_buffer_t * b0,
 664                        ip4_header_t * ip0,
 665                        icmp46_header_t * icmp0,
 666                        u32 sw_if_index0,
 667                        u32 rx_fib_index0,
 668                        vlib_node_runtime_t * node,
 669                        u32 next0, f64 now,
 670                        u32 thread_index, snat_session_t ** p_s0)
 671 {
 672   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 673                        next0, thread_index, p_s0, 0);
 674   snat_session_t *s0 = *p_s0;
 675   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
 676     {
 677       /* Accounting */
 678       nat44_session_update_counters (s0, now,
 679                                      vlib_buffer_length_in_chain
 680                                      (sm->vlib_main, b0), thread_index);
 681       /* Per-user LRU list maintenance */
 682       nat44_session_update_lru (sm, s0, thread_index);
 683     }
 684   return next0;
 685 }
 686
 687 static int
 688 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 689                              vlib_buffer_t * b,
 690                              ip4_header_t * ip, u32 rx_fib_index)
 691 {
 692   clib_bihash_kv_8_8_t kv, value;
 693   snat_static_mapping_t *m;
 694   snat_session_key_t m_key;
 695   u32 old_addr, new_addr;
 696   ip_csum_t sum;
 697
 698   m_key.addr = ip->dst_address;
 699   m_key.port = 0;
 700   m_key.protocol = 0;
 701   m_key.fib_index = 0;
 702   kv.key = m_key.as_u64;
 703   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 704     return 1;
 705
 706   m = pool_elt_at_index (sm->static_mappings, value.value);
 707
 708   old_addr = ip->dst_address.as_u32;
 709   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 710   sum = ip->checksum;
 711   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 712   ip->checksum = ip_csum_fold (sum);
 713
 714   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 715   return 0;
 716 }
 717
 718 VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 719                                  vlib_node_runtime_t * node,
 720                                  vlib_frame_t * frame)
 721 {
 722   u32 n_left_from, *from, *to_next;
 723   snat_out2in_next_t next_index;
 724   u32 pkts_processed = 0;
 725   snat_main_t *sm = &snat_main;
 726   f64 now = vlib_time_now (vm);
 727   u32 thread_index = vm->thread_index;
 728   u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
 729     0, fragments = 0;
 730
 731   from = vlib_frame_vector_args (frame);
 732   n_left_from = frame->n_vectors;
 733   next_index = node->cached_next_index;
 734
 735   while (n_left_from > 0)
 736     {
 737       u32 n_left_to_next;
 738
 739       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 740
 741       while (n_left_from >= 4 && n_left_to_next >= 2)
 742         {
 743           u32 bi0, bi1;
 744           vlib_buffer_t *b0, *b1;
 745           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 746           u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 747           u32 sw_if_index0, sw_if_index1;
 748           ip4_header_t *ip0, *ip1;
 749           ip_csum_t sum0, sum1;
 750           u32 new_addr0, old_addr0;
 751           u16 new_port0, old_port0;
 752           u32 new_addr1, old_addr1;
 753           u16 new_port1, old_port1;
 754           udp_header_t *udp0, *udp1;
 755           tcp_header_t *tcp0, *tcp1;
 756           icmp46_header_t *icmp0, *icmp1;
 757           snat_session_key_t key0, key1, sm0, sm1;
 758           u32 rx_fib_index0, rx_fib_index1;
 759           u32 proto0, proto1;
 760           snat_session_t *s0 = 0, *s1 = 0;
 761           clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
 762           u8 identity_nat0, identity_nat1;
 763
 764           /* Prefetch next iteration. */
 765           {
 766             vlib_buffer_t *p2, *p3;
 767
 768             p2 = vlib_get_buffer (vm, from[2]);
 769             p3 = vlib_get_buffer (vm, from[3]);
 770
 771             vlib_prefetch_buffer_header (p2, LOAD);
 772             vlib_prefetch_buffer_header (p3, LOAD);
 773
 774             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 775             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 776           }
 777
 778           /* speculatively enqueue b0 and b1 to the current next frame */
 779           to_next[0] = bi0 = from[0];
 780           to_next[1] = bi1 = from[1];
 781           from += 2;
 782           to_next += 2;
 783           n_left_from -= 2;
 784           n_left_to_next -= 2;
 785
 786           b0 = vlib_get_buffer (vm, bi0);
 787           b1 = vlib_get_buffer (vm, bi1);
 788
 789           vnet_buffer (b0)->snat.flags = 0;
 790           vnet_buffer (b1)->snat.flags = 0;
 791
 792           ip0 = vlib_buffer_get_current (b0);
 793           udp0 = ip4_next_header (ip0);
 794           tcp0 = (tcp_header_t *) udp0;
 795           icmp0 = (icmp46_header_t *) udp0;
 796
 797           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 798           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 799                                    sw_if_index0);
 800
 801           if (PREDICT_FALSE (ip0->ttl == 1))
 802             {
 803               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 804               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 805                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 806                                            0);
 807               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 808               goto trace0;
 809             }
 810
 811           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 812
 813           if (PREDICT_FALSE (proto0 == ~0))
 814             {
 815               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 816                 {
 817                   if (!sm->forwarding_enabled)
 818                     {
 819                       b0->error =
 820                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 821                       next0 = SNAT_OUT2IN_NEXT_DROP;
 822                     }
 823                 }
 824               other_packets++;
 825               goto trace0;
 826             }
 827
 828           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 829             {
 830               next0 = icmp_out2in_slow_path
 831                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 832                  next0, now, thread_index, &s0);
 833               icmp_packets++;
 834               goto trace0;
 835             }
 836
 837           key0.addr = ip0->dst_address;
 838           key0.port = vnet_buffer (b0)->ip.reass.l4_dst_port;
 839           key0.protocol = proto0;
 840           key0.fib_index = rx_fib_index0;
 841
 842           kv0.key = key0.as_u64;
 843
 844           if (clib_bihash_search_8_8
 845               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
 846             {
 847               /* Try to match static mapping by external address and port,
 848                  destination address and port in packet */
 849               if (snat_static_mapping_match
 850                   (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
 851                 {
 852                   /*
 853                    * Send DHCP packets to the ipv4 stack, or we won't
 854                    * be able to use dhcp client on the outside interface
 855                    */
 856                   if (PREDICT_FALSE
 857                       (proto0 == SNAT_PROTOCOL_UDP
 858                        && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
 859                            clib_host_to_net_u16
 860                            (UDP_DST_PORT_dhcp_to_client))))
 861                     {
 862                       vnet_feature_next (&next0, b0);
 863                       goto trace0;
 864                     }
 865
 866                   if (!sm->forwarding_enabled)
 867                     {
 868                       b0->error =
 869                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 870                       next0 = SNAT_OUT2IN_NEXT_DROP;
 871                     }
 872                   goto trace0;
 873                 }
 874
 875               if (PREDICT_FALSE (identity_nat0))
 876                 goto trace0;
 877
 878               /* Create session initiated by host from external network */
 879               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
 880                                                       thread_index, now);
 881               if (!s0)
 882                 {
 883                   next0 = SNAT_OUT2IN_NEXT_DROP;
 884                   goto trace0;
 885                 }
 886             }
 887           else
 888             s0 =
 889               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
 890                                  value0.value);
 891
 892           old_addr0 = ip0->dst_address.as_u32;
 893           ip0->dst_address = s0->in2out.addr;
 894           new_addr0 = ip0->dst_address.as_u32;
 895           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 896
 897           sum0 = ip0->checksum;
 898           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 899                                  ip4_header_t,
 900                                  dst_address /* changed member */ );
 901           ip0->checksum = ip_csum_fold (sum0);
 902
 903           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 904             {
 905               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 906                 {
 907                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 908                   new_port0 = udp0->dst_port = s0->in2out.port;
 909                   sum0 = tcp0->checksum;
 910                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 911                                          ip4_header_t,
 912                                          dst_address /* changed member */ );
 913
 914                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
 915                                          ip4_header_t /* cheat */ ,
 916                                          length /* changed member */ );
 917                   tcp0->checksum = ip_csum_fold (sum0);
 918                 }
 919               tcp_packets++;
 920             }
 921           else
 922             {
 923               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 924                 {
 925                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 926                   new_port0 = udp0->dst_port = s0->in2out.port;
 927                   if (PREDICT_FALSE (udp0->checksum))
 928                     {
 929                       sum0 = udp0->checksum;
 930                       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address      /* changed member */
 931                         );
 932                       sum0 =
 933                         ip_csum_update (sum0, old_port0, new_port0,
 934                                         ip4_header_t /* cheat */ ,
 935                                         length /* changed member */ );
 936                       udp0->checksum = ip_csum_fold (sum0);
 937                     }
 938                 }
 939               udp_packets++;
 940             }
 941
 942           /* Accounting */
 943           nat44_session_update_counters (s0, now,
 944                                          vlib_buffer_length_in_chain (vm, b0),
 945                                          thread_index);
 946           /* Per-user LRU list maintenance */
 947           nat44_session_update_lru (sm, s0, thread_index);
 948         trace0:
 949
 950           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 951                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 952             {
 953               snat_out2in_trace_t *t =
 954                 vlib_add_trace (vm, node, b0, sizeof (*t));
 955               t->sw_if_index = sw_if_index0;
 956               t->next_index = next0;
 957               t->session_index = ~0;
 958               if (s0)
 959                 t->session_index =
 960                   s0 - sm->per_thread_data[thread_index].sessions;
 961             }
 962
 963           pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
 964
 965
 966           ip1 = vlib_buffer_get_current (b1);
 967           udp1 = ip4_next_header (ip1);
 968           tcp1 = (tcp_header_t *) udp1;
 969           icmp1 = (icmp46_header_t *) udp1;
 970
 971           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 972           rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 973                                    sw_if_index1);
 974
 975           if (PREDICT_FALSE (ip1->ttl == 1))
 976             {
 977               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 978               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 979                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 980                                            0);
 981               next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 982               goto trace1;
 983             }
 984
 985           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 986
 987           if (PREDICT_FALSE (proto1 == ~0))
 988             {
 989               if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
 990                 {
 991                   if (!sm->forwarding_enabled)
 992                     {
 993                       b1->error =
 994                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 995                       next1 = SNAT_OUT2IN_NEXT_DROP;
 996                     }
 997                 }
 998               other_packets++;
 999               goto trace1;
1000             }
1001
1002           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
1003             {
1004               next1 = icmp_out2in_slow_path
1005                 (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
1006                  next1, now, thread_index, &s1);
1007               icmp_packets++;
1008               goto trace1;
1009             }
1010
1011           key1.addr = ip1->dst_address;
1012           key1.port = vnet_buffer (b1)->ip.reass.l4_dst_port;
1013           key1.protocol = proto1;
1014           key1.fib_index = rx_fib_index1;
1015
1016           kv1.key = key1.as_u64;
1017
1018           if (clib_bihash_search_8_8
1019               (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
1020             {
1021               /* Try to match static mapping by external address and port,
1022                  destination address and port in packet */
1023               if (snat_static_mapping_match
1024                   (sm, key1, &sm1, 1, 0, 0, 0, 0, &identity_nat1))
1025                 {
1026                   /*
1027                    * Send DHCP packets to the ipv4 stack, or we won't
1028                    * be able to use dhcp client on the outside interface
1029                    */
1030                   if (PREDICT_FALSE
1031                       (proto1 == SNAT_PROTOCOL_UDP
1032                        && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
1033                            clib_host_to_net_u16
1034                            (UDP_DST_PORT_dhcp_to_client))))
1035                     {
1036                       vnet_feature_next (&next1, b1);
1037                       goto trace1;
1038                     }
1039
1040                   if (!sm->forwarding_enabled)
1041                     {
1042                       b1->error =
1043                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1044                       next1 = SNAT_OUT2IN_NEXT_DROP;
1045                     }
1046                   goto trace1;
1047                 }
1048
1049               if (PREDICT_FALSE (identity_nat1))
1050                 goto trace1;
1051
1052               /* Create session initiated by host from external network */
1053               s1 = create_session_for_static_mapping (sm, b1, sm1, key1, node,
1054                                                       thread_index, now);
1055               if (!s1)
1056                 {
1057                   next1 = SNAT_OUT2IN_NEXT_DROP;
1058                   goto trace1;
1059                 }
1060             }
1061           else
1062             s1 =
1063               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1064                                  value1.value);
1065
1066           old_addr1 = ip1->dst_address.as_u32;
1067           ip1->dst_address = s1->in2out.addr;
1068           new_addr1 = ip1->dst_address.as_u32;
1069           vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1070
1071           sum1 = ip1->checksum;
1072           sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1073                                  ip4_header_t,
1074                                  dst_address /* changed member */ );
1075           ip1->checksum = ip_csum_fold (sum1);
1076
1077           if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
1078             {
1079               if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1080                 {
1081                   old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1082                   new_port1 = udp1->dst_port = s1->in2out.port;
1083
1084                   sum1 = tcp1->checksum;
1085                   sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1086                                          ip4_header_t,
1087                                          dst_address /* changed member */ );
1088
1089                   sum1 = ip_csum_update (sum1, old_port1, new_port1,
1090                                          ip4_header_t /* cheat */ ,
1091                                          length /* changed member */ );
1092                   tcp1->checksum = ip_csum_fold (sum1);
1093                 }
1094               tcp_packets++;
1095             }
1096           else
1097             {
1098               if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1099                 {
1100                   old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1101                   new_port1 = udp1->dst_port = s1->in2out.port;
1102                   if (PREDICT_FALSE (udp1->checksum))
1103                     {
1104
1105                       sum1 = udp1->checksum;
1106                       sum1 =
1107                         ip_csum_update (sum1, old_addr1, new_addr1,
1108                                         ip4_header_t,
1109                                         dst_address /* changed member */ );
1110                       sum1 =
1111                         ip_csum_update (sum1, old_port1, new_port1,
1112                                         ip4_header_t /* cheat */ ,
1113                                         length /* changed member */ );
1114                       udp1->checksum = ip_csum_fold (sum1);
1115                     }
1116                 }
1117               udp_packets++;
1118             }
1119
1120           /* Accounting */
1121           nat44_session_update_counters (s1, now,
1122                                          vlib_buffer_length_in_chain (vm, b1),
1123                                          thread_index);
1124           /* Per-user LRU list maintenance */
1125           nat44_session_update_lru (sm, s1, thread_index);
1126         trace1:
1127
1128           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1129                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1130             {
1131               snat_out2in_trace_t *t =
1132                 vlib_add_trace (vm, node, b1, sizeof (*t));
1133               t->sw_if_index = sw_if_index1;
1134               t->next_index = next1;
1135               t->session_index = ~0;
1136               if (s1)
1137                 t->session_index =
1138                   s1 - sm->per_thread_data[thread_index].sessions;
1139             }
1140
1141           pkts_processed += next1 == SNAT_OUT2IN_NEXT_LOOKUP;
1142
1143           /* verify speculative enqueues, maybe switch current next frame */
1144           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
1145                                            to_next, n_left_to_next,
1146                                            bi0, bi1, next0, next1);
1147         }
1148
1149       while (n_left_from > 0 && n_left_to_next > 0)
1150         {
1151           u32 bi0;
1152           vlib_buffer_t *b0;
1153           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1154           u32 sw_if_index0;
1155           ip4_header_t *ip0;
1156           ip_csum_t sum0;
1157           u32 new_addr0, old_addr0;
1158           u16 new_port0, old_port0;
1159           udp_header_t *udp0;
1160           tcp_header_t *tcp0;
1161           icmp46_header_t *icmp0;
1162           snat_session_key_t key0, sm0;
1163           u32 rx_fib_index0;
1164           u32 proto0;
1165           snat_session_t *s0 = 0;
1166           clib_bihash_kv_8_8_t kv0, value0;
1167           u8 identity_nat0;
1168
1169           /* speculatively enqueue b0 to the current next frame */
1170           bi0 = from[0];
1171           to_next[0] = bi0;
1172           from += 1;
1173           to_next += 1;
1174           n_left_from -= 1;
1175           n_left_to_next -= 1;
1176
1177           b0 = vlib_get_buffer (vm, bi0);
1178
1179           vnet_buffer (b0)->snat.flags = 0;
1180
1181           ip0 = vlib_buffer_get_current (b0);
1182           udp0 = ip4_next_header (ip0);
1183           tcp0 = (tcp_header_t *) udp0;
1184           icmp0 = (icmp46_header_t *) udp0;
1185
1186           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1187           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1188                                    sw_if_index0);
1189
1190           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1191
1192           if (PREDICT_FALSE (proto0 == ~0))
1193             {
1194               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1195                 {
1196                   if (!sm->forwarding_enabled)
1197                     {
1198                       b0->error =
1199                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1200                       next0 = SNAT_OUT2IN_NEXT_DROP;
1201                     }
1202                 }
1203               other_packets++;
1204               goto trace00;
1205             }
1206
1207           if (PREDICT_FALSE (ip0->ttl == 1))
1208             {
1209               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1210               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1211                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1212                                            0);
1213               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1214               goto trace00;
1215             }
1216
1217           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1218             {
1219               next0 = icmp_out2in_slow_path
1220                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1221                  next0, now, thread_index, &s0);
1222               icmp_packets++;
1223               goto trace00;
1224             }
1225
1226           key0.addr = ip0->dst_address;
1227           key0.port = vnet_buffer (b0)->ip.reass.l4_dst_port;
1228           key0.protocol = proto0;
1229           key0.fib_index = rx_fib_index0;
1230
1231           kv0.key = key0.as_u64;
1232
1233           if (clib_bihash_search_8_8
1234               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
1235             {
1236               /* Try to match static mapping by external address and port,
1237                  destination address and port in packet */
1238               if (snat_static_mapping_match
1239                   (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
1240                 {
1241                   /*
1242                    * Send DHCP packets to the ipv4 stack, or we won't
1243                    * be able to use dhcp client on the outside interface
1244                    */
1245                   if (PREDICT_FALSE
1246                       (proto0 == SNAT_PROTOCOL_UDP
1247                        && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
1248                            clib_host_to_net_u16
1249                            (UDP_DST_PORT_dhcp_to_client))))
1250                     {
1251                       vnet_feature_next (&next0, b0);
1252                       goto trace00;
1253                     }
1254
1255                   if (!sm->forwarding_enabled)
1256                     {
1257                       b0->error =
1258                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1259                       next0 = SNAT_OUT2IN_NEXT_DROP;
1260                     }
1261                   goto trace00;
1262                 }
1263
1264               if (PREDICT_FALSE (identity_nat0))
1265                 goto trace00;
1266
1267               /* Create session initiated by host from external network */
1268               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
1269                                                       thread_index, now);
1270               if (!s0)
1271                 {
1272                   next0 = SNAT_OUT2IN_NEXT_DROP;
1273                   goto trace00;
1274                 }
1275             }
1276           else
1277             s0 =
1278               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1279                                  value0.value);
1280
1281           old_addr0 = ip0->dst_address.as_u32;
1282           ip0->dst_address = s0->in2out.addr;
1283           new_addr0 = ip0->dst_address.as_u32;
1284           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1285
1286           sum0 = ip0->checksum;
1287           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1288                                  ip4_header_t,
1289                                  dst_address /* changed member */ );
1290           ip0->checksum = ip_csum_fold (sum0);
1291
1292           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1293             {
1294               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1295                 {
1296                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1297                   new_port0 = udp0->dst_port = s0->in2out.port;
1298
1299                   sum0 = tcp0->checksum;
1300                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1301                                          ip4_header_t,
1302                                          dst_address /* changed member */ );
1303
1304                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1305                                          ip4_header_t /* cheat */ ,
1306                                          length /* changed member */ );
1307                   tcp0->checksum = ip_csum_fold (sum0);
1308                 }
1309               tcp_packets++;
1310             }
1311           else
1312             {
1313               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1314                 {
1315                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1316                   new_port0 = udp0->dst_port = s0->in2out.port;
1317                   if (PREDICT_FALSE (udp0->checksum))
1318                     {
1319                       sum0 = udp0->checksum;
1320                       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address      /* changed member */
1321                         );
1322                       sum0 =
1323                         ip_csum_update (sum0, old_port0, new_port0,
1324                                         ip4_header_t /* cheat */ ,
1325                                         length /* changed member */ );
1326                       udp0->checksum = ip_csum_fold (sum0);
1327                     }
1328                 }
1329               udp_packets++;
1330             }
1331
1332           /* Accounting */
1333           nat44_session_update_counters (s0, now,
1334                                          vlib_buffer_length_in_chain (vm, b0),
1335                                          thread_index);
1336           /* Per-user LRU list maintenance */
1337           nat44_session_update_lru (sm, s0, thread_index);
1338         trace00:
1339
1340           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1341                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1342             {
1343               snat_out2in_trace_t *t =
1344                 vlib_add_trace (vm, node, b0, sizeof (*t));
1345               t->sw_if_index = sw_if_index0;
1346               t->next_index = next0;
1347               t->session_index = ~0;
1348               if (s0)
1349                 t->session_index =
1350                   s0 - sm->per_thread_data[thread_index].sessions;
1351             }
1352
1353           pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
1354
1355           /* verify speculative enqueue, maybe switch current next frame */
1356           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1357                                            to_next, n_left_to_next,
1358                                            bi0, next0);
1359         }
1360
1361       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1362     }
1363
1364   vlib_node_increment_counter (vm, sm->out2in_node_index,
1365                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1366                                pkts_processed);
1367   vlib_node_increment_counter (vm, sm->out2in_node_index,
1368                                SNAT_OUT2IN_ERROR_TCP_PACKETS, tcp_packets);
1369   vlib_node_increment_counter (vm, sm->out2in_node_index,
1370                                SNAT_OUT2IN_ERROR_UDP_PACKETS, udp_packets);
1371   vlib_node_increment_counter (vm, sm->out2in_node_index,
1372                                SNAT_OUT2IN_ERROR_ICMP_PACKETS, icmp_packets);
1373   vlib_node_increment_counter (vm, sm->out2in_node_index,
1374                                SNAT_OUT2IN_ERROR_OTHER_PACKETS,
1375                                other_packets);
1376   vlib_node_increment_counter (vm, sm->out2in_node_index,
1377                                SNAT_OUT2IN_ERROR_FRAGMENTS, fragments);
1378
1379   return frame->n_vectors;
1380 }
1381
1382 /* *INDENT-OFF* */
1383 VLIB_REGISTER_NODE (snat_out2in_node) = {
1384   .name = "nat44-out2in",
1385   .vector_size = sizeof (u32),
1386   .format_trace = format_snat_out2in_trace,
1387   .type = VLIB_NODE_TYPE_INTERNAL,
1388
1389   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1390   .error_strings = snat_out2in_error_strings,
1391
1392   .runtime_data_bytes = sizeof (snat_runtime_t),
1393
1394   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1395
1396   /* edit / add dispositions here */
1397   .next_nodes = {
1398     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1399     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1400     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1401   },
1402 };
1403 /* *INDENT-ON* */
1404
1405 VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
1406                                       vlib_node_runtime_t * node,
1407                                       vlib_frame_t * frame)
1408 {
1409   u32 n_left_from, *from, *to_next;
1410   snat_out2in_next_t next_index;
1411   u32 pkts_processed = 0;
1412   snat_main_t *sm = &snat_main;
1413
1414   from = vlib_frame_vector_args (frame);
1415   n_left_from = frame->n_vectors;
1416   next_index = node->cached_next_index;
1417
1418   while (n_left_from > 0)
1419     {
1420       u32 n_left_to_next;
1421
1422       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1423
1424       while (n_left_from > 0 && n_left_to_next > 0)
1425         {
1426           u32 bi0;
1427           vlib_buffer_t *b0;
1428           u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1429           u32 sw_if_index0;
1430           ip4_header_t *ip0;
1431           ip_csum_t sum0;
1432           u32 new_addr0, old_addr0;
1433           u16 new_port0, old_port0;
1434           udp_header_t *udp0;
1435           tcp_header_t *tcp0;
1436           icmp46_header_t *icmp0;
1437           snat_session_key_t key0, sm0;
1438           u32 proto0;
1439           u32 rx_fib_index0;
1440
1441           /* speculatively enqueue b0 to the current next frame */
1442           bi0 = from[0];
1443           to_next[0] = bi0;
1444           from += 1;
1445           to_next += 1;
1446           n_left_from -= 1;
1447           n_left_to_next -= 1;
1448
1449           b0 = vlib_get_buffer (vm, bi0);
1450
1451           ip0 = vlib_buffer_get_current (b0);
1452           udp0 = ip4_next_header (ip0);
1453           tcp0 = (tcp_header_t *) udp0;
1454           icmp0 = (icmp46_header_t *) udp0;
1455
1456           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1457           rx_fib_index0 =
1458             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1459
1460           vnet_feature_next (&next0, b0);
1461
1462           if (PREDICT_FALSE (ip0->ttl == 1))
1463             {
1464               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1465               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1466                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1467                                            0);
1468               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1469               goto trace00;
1470             }
1471
1472           proto0 = ip_proto_to_snat_proto (ip0->protocol);
1473
1474           if (PREDICT_FALSE (proto0 == ~0))
1475             goto trace00;
1476
1477           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
1478             {
1479               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1480                                    rx_fib_index0, node, next0, ~0, 0, 0);
1481               goto trace00;
1482             }
1483
1484           key0.addr = ip0->dst_address;
1485           key0.port = udp0->dst_port;
1486           key0.fib_index = rx_fib_index0;
1487
1488           if (snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0, 0))
1489             {
1490               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1491               goto trace00;
1492             }
1493
1494           new_addr0 = sm0.addr.as_u32;
1495           new_port0 = sm0.port;
1496           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
1497           old_addr0 = ip0->dst_address.as_u32;
1498           ip0->dst_address.as_u32 = new_addr0;
1499
1500           sum0 = ip0->checksum;
1501           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1502                                  ip4_header_t,
1503                                  dst_address /* changed member */ );
1504           ip0->checksum = ip_csum_fold (sum0);
1505
1506           if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1507             {
1508               old_port0 = udp0->dst_port;
1509               udp0->dst_port = new_port0;
1510
1511               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1512                 {
1513                   sum0 = tcp0->checksum;
1514                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1515                                          ip4_header_t,
1516                                          dst_address /* changed member */ );
1517                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1518                                          ip4_header_t /* cheat */ ,
1519                                          length /* changed member */ );
1520                   tcp0->checksum = ip_csum_fold (sum0);
1521                 }
1522               else if (udp0->checksum)
1523                 {
1524                   sum0 = udp0->checksum;
1525                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1526                                          ip4_header_t,
1527                                          dst_address /* changed member */ );
1528                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1529                                          ip4_header_t /* cheat */ ,
1530                                          length /* changed member */ );
1531                   udp0->checksum = ip_csum_fold (sum0);
1532                 }
1533             }
1534           else
1535             {
1536               if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
1537                 {
1538                   sum0 = tcp0->checksum;
1539                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1540                                          ip4_header_t,
1541                                          dst_address /* changed member */ );
1542                   tcp0->checksum = ip_csum_fold (sum0);
1543                 }
1544               else if (udp0->checksum)
1545                 {
1546                   sum0 = udp0->checksum;
1547                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1548                                          ip4_header_t,
1549                                          dst_address /* changed member */ );
1550                   udp0->checksum = ip_csum_fold (sum0);
1551                 }
1552             }
1553
1554         trace00:
1555
1556           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1557                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1558             {
1559               snat_out2in_trace_t *t =
1560                 vlib_add_trace (vm, node, b0, sizeof (*t));
1561               t->sw_if_index = sw_if_index0;
1562               t->next_index = next0;
1563             }
1564
1565           pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1566
1567           /* verify speculative enqueue, maybe switch current next frame */
1568           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1569                                            to_next, n_left_to_next,
1570                                            bi0, next0);
1571         }
1572
1573       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1574     }
1575
1576   vlib_node_increment_counter (vm, sm->out2in_fast_node_index,
1577                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1578                                pkts_processed);
1579   return frame->n_vectors;
1580 }
1581
1582 /* *INDENT-OFF* */
1583 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1584   .name = "nat44-out2in-fast",
1585   .vector_size = sizeof (u32),
1586   .format_trace = format_snat_out2in_fast_trace,
1587   .type = VLIB_NODE_TYPE_INTERNAL,
1588
1589   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1590   .error_strings = snat_out2in_error_strings,
1591
1592   .runtime_data_bytes = sizeof (snat_runtime_t),
1593
1594   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1595
1596   /* edit / add dispositions here */
1597   .next_nodes = {
1598     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1599     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1600     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1601   },
1602 };
1603 /* *INDENT-ON* */
1604
1605 /*
1606  * fd.io coding-style-patch-verification: ON
1607  *
1608  * Local Variables:
1609  * eval: (c-set-style "gnu")
1610  * End:
1611  */