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 = NAT_PROTOCOL_ICMP;
 282       key0.addr = ip0->dst_address;
 283       key0.port = vnet_buffer (b)->ip.reass.l4_src_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_nat_proto (inner_ip0->protocol);
 290       key0.addr = inner_ip0->src_address;
 291       switch (key0.protocol)
 292         {
 293         case NAT_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 NAT_PROTOCOL_UDP:
 299         case NAT_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   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 333   u32 sw_if_index0;
 334   u32 rx_fib_index0;
 335   snat_session_key_t key0;
 336   snat_session_key_t sm0;
 337   snat_session_t *s0 = 0;
 338   u8 dont_translate = 0;
 339   clib_bihash_kv_8_8_t kv0, value0;
 340   u8 is_addr_only;
 341   u32 next0 = ~0;
 342   int err;
 343   u8 identity_nat;
 344   vlib_main_t *vm = vlib_get_main ();
 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 (&tsm->out2in, &kv0, &value0))
 363     {
 364       /* Try to match static mapping by external address and port,
 365          destination address and port in packet */
 366       if (snat_static_mapping_match
 367           (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0, &identity_nat))
 368         {
 369           if (!sm->forwarding_enabled)
 370             {
 371               /* Don't NAT packet aimed at the intfc address */
 372               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 373                                                     ip0->dst_address.as_u32)))
 374                 {
 375                   dont_translate = 1;
 376                   goto out;
 377                 }
 378               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 379               next0 = SNAT_OUT2IN_NEXT_DROP;
 380               goto out;
 381             }
 382           else
 383             {
 384               dont_translate = 1;
 385               goto out;
 386             }
 387         }
 388
 389       if (PREDICT_FALSE
 390           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 391            ICMP4_echo_reply
 392            && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 393                ICMP4_echo_request || !is_addr_only)))
 394         {
 395           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 396           next0 = SNAT_OUT2IN_NEXT_DROP;
 397           goto out;
 398         }
 399
 400       if (PREDICT_FALSE (identity_nat))
 401         {
 402           dont_translate = 1;
 403           goto out;
 404         }
 405       /* Create session initiated by host from external network */
 406       s0 = create_session_for_static_mapping (sm, b0, sm0, key0,
 407                                               node, thread_index,
 408                                               vlib_time_now (vm));
 409
 410       if (!s0)
 411         {
 412           next0 = SNAT_OUT2IN_NEXT_DROP;
 413           goto out;
 414         }
 415     }
 416   else
 417     {
 418       if (PREDICT_FALSE
 419           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 420            ICMP4_echo_reply
 421            && vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 422            ICMP4_echo_request
 423            && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 424                                            reass.icmp_type_or_tcp_flags)))
 425         {
 426           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 427           next0 = SNAT_OUT2IN_NEXT_DROP;
 428           goto out;
 429         }
 430
 431       s0 = pool_elt_at_index (tsm->sessions, 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   vlib_main_t *vm = vlib_get_main ();
 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 =
 561         ip_incremental_checksum_buffer (vm, b0,
 562                                         (u8 *) icmp0 -
 563                                         (u8 *) vlib_buffer_get_current (b0),
 564                                         ntohs (ip0->length) -
 565                                         ip4_header_bytes (ip0), 0);
 566       checksum0 = ~ip_csum_fold (sum0);
 567       if (checksum0 != 0 && checksum0 != 0xffff)
 568         {
 569           next0 = SNAT_OUT2IN_NEXT_DROP;
 570           goto out;
 571         }
 572     }
 573
 574   old_addr0 = ip0->dst_address.as_u32;
 575   new_addr0 = ip0->dst_address.as_u32 = sm0.addr.as_u32;
 576   vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
 577
 578   sum0 = ip0->checksum;
 579   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 580                          dst_address /* changed member */ );
 581   ip0->checksum = ip_csum_fold (sum0);
 582
 583
 584   if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 585     {
 586       if (icmp0->checksum == 0)
 587         icmp0->checksum = 0xffff;
 588
 589       if (!icmp_type_is_error_message (icmp0->type))
 590         {
 591           new_id0 = sm0.port;
 592           if (PREDICT_FALSE (new_id0 != echo0->identifier))
 593             {
 594               old_id0 = echo0->identifier;
 595               new_id0 = sm0.port;
 596               echo0->identifier = new_id0;
 597
 598               sum0 = icmp0->checksum;
 599               sum0 =
 600                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 601                                 identifier /* changed member */ );
 602               icmp0->checksum = ip_csum_fold (sum0);
 603             }
 604         }
 605       else
 606         {
 607           inner_ip0 = (ip4_header_t *) (echo0 + 1);
 608           l4_header = ip4_next_header (inner_ip0);
 609
 610           if (!ip4_header_checksum_is_valid (inner_ip0))
 611             {
 612               next0 = SNAT_OUT2IN_NEXT_DROP;
 613               goto out;
 614             }
 615
 616           old_addr0 = inner_ip0->src_address.as_u32;
 617           inner_ip0->src_address = sm0.addr;
 618           new_addr0 = inner_ip0->src_address.as_u32;
 619
 620           sum0 = icmp0->checksum;
 621           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 622                                  src_address /* changed member */ );
 623           icmp0->checksum = ip_csum_fold (sum0);
 624
 625           switch (protocol)
 626             {
 627             case NAT_PROTOCOL_ICMP:
 628               inner_icmp0 = (icmp46_header_t *) l4_header;
 629               inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 630
 631               old_id0 = inner_echo0->identifier;
 632               new_id0 = sm0.port;
 633               inner_echo0->identifier = new_id0;
 634
 635               sum0 = icmp0->checksum;
 636               sum0 =
 637                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 638                                 identifier);
 639               icmp0->checksum = ip_csum_fold (sum0);
 640               break;
 641             case NAT_PROTOCOL_UDP:
 642             case NAT_PROTOCOL_TCP:
 643               old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 644               new_id0 = sm0.port;
 645               ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 646
 647               sum0 = icmp0->checksum;
 648               sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 649                                      src_port);
 650               icmp0->checksum = ip_csum_fold (sum0);
 651               break;
 652             default:
 653               ASSERT (0);
 654             }
 655         }
 656     }
 657
 658 out:
 659   return next0;
 660 }
 661 #endif
 662
 663 static inline u32
 664 icmp_out2in_slow_path (snat_main_t * sm,
 665                        vlib_buffer_t * b0,
 666                        ip4_header_t * ip0,
 667                        icmp46_header_t * icmp0,
 668                        u32 sw_if_index0,
 669                        u32 rx_fib_index0,
 670                        vlib_node_runtime_t * node,
 671                        u32 next0, f64 now,
 672                        u32 thread_index, snat_session_t ** p_s0)
 673 {
 674   vlib_main_t *vm = vlib_get_main ();
 675
 676   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 677                        next0, thread_index, p_s0, 0);
 678   snat_session_t *s0 = *p_s0;
 679   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
 680     {
 681       /* Accounting */
 682       nat44_session_update_counters (s0, now,
 683                                      vlib_buffer_length_in_chain
 684                                      (vm, b0), thread_index);
 685       /* Per-user LRU list maintenance */
 686       nat44_session_update_lru (sm, s0, thread_index);
 687     }
 688   return next0;
 689 }
 690
 691 static int
 692 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 693                              vlib_buffer_t * b,
 694                              ip4_header_t * ip, u32 rx_fib_index)
 695 {
 696   clib_bihash_kv_8_8_t kv, value;
 697   snat_static_mapping_t *m;
 698   snat_session_key_t m_key;
 699   u32 old_addr, new_addr;
 700   ip_csum_t sum;
 701
 702   m_key.addr = ip->dst_address;
 703   m_key.port = 0;
 704   m_key.protocol = 0;
 705   m_key.fib_index = 0;
 706   kv.key = m_key.as_u64;
 707   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 708     return 1;
 709
 710   m = pool_elt_at_index (sm->static_mappings, value.value);
 711
 712   old_addr = ip->dst_address.as_u32;
 713   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 714   sum = ip->checksum;
 715   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 716   ip->checksum = ip_csum_fold (sum);
 717
 718   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 719   return 0;
 720 }
 721
 722 VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 723                                  vlib_node_runtime_t * node,
 724                                  vlib_frame_t * frame)
 725 {
 726   u32 n_left_from, *from, *to_next;
 727   snat_out2in_next_t next_index;
 728   u32 pkts_processed = 0;
 729   snat_main_t *sm = &snat_main;
 730   f64 now = vlib_time_now (vm);
 731   u32 thread_index = vm->thread_index;
 732   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 733   u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
 734     0, fragments = 0;
 735
 736   from = vlib_frame_vector_args (frame);
 737   n_left_from = frame->n_vectors;
 738   next_index = node->cached_next_index;
 739
 740   while (n_left_from > 0)
 741     {
 742       u32 n_left_to_next;
 743
 744       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 745
 746       while (n_left_from >= 4 && n_left_to_next >= 2)
 747         {
 748           u32 bi0, bi1;
 749           vlib_buffer_t *b0, *b1;
 750           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 751           u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 752           u32 sw_if_index0, sw_if_index1;
 753           ip4_header_t *ip0, *ip1;
 754           ip_csum_t sum0, sum1;
 755           u32 new_addr0, old_addr0;
 756           u16 new_port0, old_port0;
 757           u32 new_addr1, old_addr1;
 758           u16 new_port1, old_port1;
 759           udp_header_t *udp0, *udp1;
 760           tcp_header_t *tcp0, *tcp1;
 761           icmp46_header_t *icmp0, *icmp1;
 762           snat_session_key_t key0, key1, sm0, sm1;
 763           u32 rx_fib_index0, rx_fib_index1;
 764           u32 proto0, proto1;
 765           snat_session_t *s0 = 0, *s1 = 0;
 766           clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
 767           u8 identity_nat0, identity_nat1;
 768
 769           /* Prefetch next iteration. */
 770           {
 771             vlib_buffer_t *p2, *p3;
 772
 773             p2 = vlib_get_buffer (vm, from[2]);
 774             p3 = vlib_get_buffer (vm, from[3]);
 775
 776             vlib_prefetch_buffer_header (p2, LOAD);
 777             vlib_prefetch_buffer_header (p3, LOAD);
 778
 779             CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 780             CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 781           }
 782
 783           /* speculatively enqueue b0 and b1 to the current next frame */
 784           to_next[0] = bi0 = from[0];
 785           to_next[1] = bi1 = from[1];
 786           from += 2;
 787           to_next += 2;
 788           n_left_from -= 2;
 789           n_left_to_next -= 2;
 790
 791           b0 = vlib_get_buffer (vm, bi0);
 792           b1 = vlib_get_buffer (vm, bi1);
 793
 794           vnet_buffer (b0)->snat.flags = 0;
 795           vnet_buffer (b1)->snat.flags = 0;
 796
 797           ip0 = vlib_buffer_get_current (b0);
 798           udp0 = ip4_next_header (ip0);
 799           tcp0 = (tcp_header_t *) udp0;
 800           icmp0 = (icmp46_header_t *) udp0;
 801
 802           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 803           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 804                                    sw_if_index0);
 805
 806           if (PREDICT_FALSE (ip0->ttl == 1))
 807             {
 808               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 809               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 810                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 811                                            0);
 812               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 813               goto trace0;
 814             }
 815
 816           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 817
 818           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 819             {
 820               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 821                 {
 822                   if (!sm->forwarding_enabled)
 823                     {
 824                       b0->error =
 825                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 826                       next0 = SNAT_OUT2IN_NEXT_DROP;
 827                     }
 828                 }
 829               other_packets++;
 830               goto trace0;
 831             }
 832
 833           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 834             {
 835               next0 = icmp_out2in_slow_path
 836                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 837                  next0, now, thread_index, &s0);
 838               icmp_packets++;
 839               goto trace0;
 840             }
 841
 842           key0.addr = ip0->dst_address;
 843           key0.port = vnet_buffer (b0)->ip.reass.l4_dst_port;
 844           key0.protocol = proto0;
 845           key0.fib_index = rx_fib_index0;
 846
 847           kv0.key = key0.as_u64;
 848
 849           if (clib_bihash_search_8_8
 850               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
 851             {
 852               /* Try to match static mapping by external address and port,
 853                  destination address and port in packet */
 854               if (snat_static_mapping_match
 855                   (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
 856                 {
 857                   /*
 858                    * Send DHCP packets to the ipv4 stack, or we won't
 859                    * be able to use dhcp client on the outside interface
 860                    */
 861                   if (PREDICT_FALSE
 862                       (proto0 == NAT_PROTOCOL_UDP
 863                        && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
 864                            clib_host_to_net_u16
 865                            (UDP_DST_PORT_dhcp_to_client))))
 866                     {
 867                       vnet_feature_next (&next0, b0);
 868                       goto trace0;
 869                     }
 870
 871                   if (!sm->forwarding_enabled)
 872                     {
 873                       b0->error =
 874                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 875                       next0 = SNAT_OUT2IN_NEXT_DROP;
 876                     }
 877                   goto trace0;
 878                 }
 879
 880               if (PREDICT_FALSE (identity_nat0))
 881                 goto trace0;
 882
 883               /* Create session initiated by host from external network */
 884               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
 885                                                       thread_index, now);
 886               if (!s0)
 887                 {
 888                   next0 = SNAT_OUT2IN_NEXT_DROP;
 889                   goto trace0;
 890                 }
 891             }
 892           else
 893             s0 = pool_elt_at_index (tsm->sessions, value0.value);
 894
 895           old_addr0 = ip0->dst_address.as_u32;
 896           ip0->dst_address = s0->in2out.addr;
 897           new_addr0 = ip0->dst_address.as_u32;
 898           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 899
 900           sum0 = ip0->checksum;
 901           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 902                                  ip4_header_t,
 903                                  dst_address /* changed member */ );
 904           ip0->checksum = ip_csum_fold (sum0);
 905
 906           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 907             {
 908               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 909                 {
 910                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 911                   new_port0 = udp0->dst_port = s0->in2out.port;
 912                   sum0 = tcp0->checksum;
 913                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 914                                          ip4_header_t,
 915                                          dst_address /* changed member */ );
 916
 917                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
 918                                          ip4_header_t /* cheat */ ,
 919                                          length /* changed member */ );
 920                   tcp0->checksum = ip_csum_fold (sum0);
 921                 }
 922               tcp_packets++;
 923             }
 924           else
 925             {
 926               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 927                 {
 928                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 929                   new_port0 = udp0->dst_port = s0->in2out.port;
 930                   if (PREDICT_FALSE (udp0->checksum))
 931                     {
 932                       sum0 = udp0->checksum;
 933                       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address      /* changed member */
 934                         );
 935                       sum0 =
 936                         ip_csum_update (sum0, old_port0, new_port0,
 937                                         ip4_header_t /* cheat */ ,
 938                                         length /* changed member */ );
 939                       udp0->checksum = ip_csum_fold (sum0);
 940                     }
 941                 }
 942               udp_packets++;
 943             }
 944
 945           /* Accounting */
 946           nat44_session_update_counters (s0, now,
 947                                          vlib_buffer_length_in_chain (vm, b0),
 948                                          thread_index);
 949           /* Per-user LRU list maintenance */
 950           nat44_session_update_lru (sm, s0, thread_index);
 951         trace0:
 952
 953           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 954                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 955             {
 956               snat_out2in_trace_t *t =
 957                 vlib_add_trace (vm, node, b0, sizeof (*t));
 958               t->sw_if_index = sw_if_index0;
 959               t->next_index = next0;
 960               t->session_index = ~0;
 961               if (s0)
 962                 t->session_index =
 963                   s0 - sm->per_thread_data[thread_index].sessions;
 964             }
 965
 966           pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
 967
 968
 969           ip1 = vlib_buffer_get_current (b1);
 970           udp1 = ip4_next_header (ip1);
 971           tcp1 = (tcp_header_t *) udp1;
 972           icmp1 = (icmp46_header_t *) udp1;
 973
 974           sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 975           rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 976                                    sw_if_index1);
 977
 978           if (PREDICT_FALSE (ip1->ttl == 1))
 979             {
 980               vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 981               icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 982                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
 983                                            0);
 984               next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 985               goto trace1;
 986             }
 987
 988           proto1 = ip_proto_to_nat_proto (ip1->protocol);
 989
 990           if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
 991             {
 992               if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
 993                 {
 994                   if (!sm->forwarding_enabled)
 995                     {
 996                       b1->error =
 997                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 998                       next1 = SNAT_OUT2IN_NEXT_DROP;
 999                     }
1000                 }
1001               other_packets++;
1002               goto trace1;
1003             }
1004
1005           if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
1006             {
1007               next1 = icmp_out2in_slow_path
1008                 (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
1009                  next1, now, thread_index, &s1);
1010               icmp_packets++;
1011               goto trace1;
1012             }
1013
1014           key1.addr = ip1->dst_address;
1015           key1.port = vnet_buffer (b1)->ip.reass.l4_dst_port;
1016           key1.protocol = proto1;
1017           key1.fib_index = rx_fib_index1;
1018
1019           kv1.key = key1.as_u64;
1020
1021           if (clib_bihash_search_8_8
1022               (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
1023             {
1024               /* Try to match static mapping by external address and port,
1025                  destination address and port in packet */
1026               if (snat_static_mapping_match
1027                   (sm, key1, &sm1, 1, 0, 0, 0, 0, &identity_nat1))
1028                 {
1029                   /*
1030                    * Send DHCP packets to the ipv4 stack, or we won't
1031                    * be able to use dhcp client on the outside interface
1032                    */
1033                   if (PREDICT_FALSE
1034                       (proto1 == NAT_PROTOCOL_UDP
1035                        && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
1036                            clib_host_to_net_u16
1037                            (UDP_DST_PORT_dhcp_to_client))))
1038                     {
1039                       vnet_feature_next (&next1, b1);
1040                       goto trace1;
1041                     }
1042
1043                   if (!sm->forwarding_enabled)
1044                     {
1045                       b1->error =
1046                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1047                       next1 = SNAT_OUT2IN_NEXT_DROP;
1048                     }
1049                   goto trace1;
1050                 }
1051
1052               if (PREDICT_FALSE (identity_nat1))
1053                 goto trace1;
1054
1055               /* Create session initiated by host from external network */
1056               s1 = create_session_for_static_mapping (sm, b1, sm1, key1, node,
1057                                                       thread_index, now);
1058               if (!s1)
1059                 {
1060                   next1 = SNAT_OUT2IN_NEXT_DROP;
1061                   goto trace1;
1062                 }
1063             }
1064           else
1065             s1 =
1066               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1067                                  value1.value);
1068
1069           old_addr1 = ip1->dst_address.as_u32;
1070           ip1->dst_address = s1->in2out.addr;
1071           new_addr1 = ip1->dst_address.as_u32;
1072           vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1073
1074           sum1 = ip1->checksum;
1075           sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1076                                  ip4_header_t,
1077                                  dst_address /* changed member */ );
1078           ip1->checksum = ip_csum_fold (sum1);
1079
1080           if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
1081             {
1082               if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1083                 {
1084                   old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1085                   new_port1 = udp1->dst_port = s1->in2out.port;
1086
1087                   sum1 = tcp1->checksum;
1088                   sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1089                                          ip4_header_t,
1090                                          dst_address /* changed member */ );
1091
1092                   sum1 = ip_csum_update (sum1, old_port1, new_port1,
1093                                          ip4_header_t /* cheat */ ,
1094                                          length /* changed member */ );
1095                   tcp1->checksum = ip_csum_fold (sum1);
1096                 }
1097               tcp_packets++;
1098             }
1099           else
1100             {
1101               if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
1102                 {
1103                   old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
1104                   new_port1 = udp1->dst_port = s1->in2out.port;
1105                   if (PREDICT_FALSE (udp1->checksum))
1106                     {
1107
1108                       sum1 = udp1->checksum;
1109                       sum1 =
1110                         ip_csum_update (sum1, old_addr1, new_addr1,
1111                                         ip4_header_t,
1112                                         dst_address /* changed member */ );
1113                       sum1 =
1114                         ip_csum_update (sum1, old_port1, new_port1,
1115                                         ip4_header_t /* cheat */ ,
1116                                         length /* changed member */ );
1117                       udp1->checksum = ip_csum_fold (sum1);
1118                     }
1119                 }
1120               udp_packets++;
1121             }
1122
1123           /* Accounting */
1124           nat44_session_update_counters (s1, now,
1125                                          vlib_buffer_length_in_chain (vm, b1),
1126                                          thread_index);
1127           /* Per-user LRU list maintenance */
1128           nat44_session_update_lru (sm, s1, thread_index);
1129         trace1:
1130
1131           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1132                              && (b1->flags & VLIB_BUFFER_IS_TRACED)))
1133             {
1134               snat_out2in_trace_t *t =
1135                 vlib_add_trace (vm, node, b1, sizeof (*t));
1136               t->sw_if_index = sw_if_index1;
1137               t->next_index = next1;
1138               t->session_index = ~0;
1139               if (s1)
1140                 t->session_index =
1141                   s1 - sm->per_thread_data[thread_index].sessions;
1142             }
1143
1144           pkts_processed += next1 == SNAT_OUT2IN_NEXT_LOOKUP;
1145
1146           /* verify speculative enqueues, maybe switch current next frame */
1147           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
1148                                            to_next, n_left_to_next,
1149                                            bi0, bi1, next0, next1);
1150         }
1151
1152       while (n_left_from > 0 && n_left_to_next > 0)
1153         {
1154           u32 bi0;
1155           vlib_buffer_t *b0;
1156           u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1157           u32 sw_if_index0;
1158           ip4_header_t *ip0;
1159           ip_csum_t sum0;
1160           u32 new_addr0, old_addr0;
1161           u16 new_port0, old_port0;
1162           udp_header_t *udp0;
1163           tcp_header_t *tcp0;
1164           icmp46_header_t *icmp0;
1165           snat_session_key_t key0, sm0;
1166           u32 rx_fib_index0;
1167           u32 proto0;
1168           snat_session_t *s0 = 0;
1169           clib_bihash_kv_8_8_t kv0, value0;
1170           u8 identity_nat0;
1171
1172           /* speculatively enqueue b0 to the current next frame */
1173           bi0 = from[0];
1174           to_next[0] = bi0;
1175           from += 1;
1176           to_next += 1;
1177           n_left_from -= 1;
1178           n_left_to_next -= 1;
1179
1180           b0 = vlib_get_buffer (vm, bi0);
1181
1182           vnet_buffer (b0)->snat.flags = 0;
1183
1184           ip0 = vlib_buffer_get_current (b0);
1185           udp0 = ip4_next_header (ip0);
1186           tcp0 = (tcp_header_t *) udp0;
1187           icmp0 = (icmp46_header_t *) udp0;
1188
1189           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1190           rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1191                                    sw_if_index0);
1192
1193           proto0 = ip_proto_to_nat_proto (ip0->protocol);
1194
1195           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1196             {
1197               if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1198                 {
1199                   if (!sm->forwarding_enabled)
1200                     {
1201                       b0->error =
1202                         node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1203                       next0 = SNAT_OUT2IN_NEXT_DROP;
1204                     }
1205                 }
1206               other_packets++;
1207               goto trace00;
1208             }
1209
1210           if (PREDICT_FALSE (ip0->ttl == 1))
1211             {
1212               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1213               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1214                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1215                                            0);
1216               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1217               goto trace00;
1218             }
1219
1220           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1221             {
1222               next0 = icmp_out2in_slow_path
1223                 (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1224                  next0, now, thread_index, &s0);
1225               icmp_packets++;
1226               goto trace00;
1227             }
1228
1229           key0.addr = ip0->dst_address;
1230           key0.port = vnet_buffer (b0)->ip.reass.l4_dst_port;
1231           key0.protocol = proto0;
1232           key0.fib_index = rx_fib_index0;
1233
1234           kv0.key = key0.as_u64;
1235
1236           if (clib_bihash_search_8_8
1237               (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
1238             {
1239               /* Try to match static mapping by external address and port,
1240                  destination address and port in packet */
1241               if (snat_static_mapping_match
1242                   (sm, key0, &sm0, 1, 0, 0, 0, 0, &identity_nat0))
1243                 {
1244                   /*
1245                    * Send DHCP packets to the ipv4 stack, or we won't
1246                    * be able to use dhcp client on the outside interface
1247                    */
1248                   if (PREDICT_FALSE
1249                       (proto0 == NAT_PROTOCOL_UDP
1250                        && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
1251                            clib_host_to_net_u16
1252                            (UDP_DST_PORT_dhcp_to_client))))
1253                     {
1254                       vnet_feature_next (&next0, b0);
1255                       goto trace00;
1256                     }
1257
1258                   if (!sm->forwarding_enabled)
1259                     {
1260                       b0->error =
1261                         node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1262                       next0 = SNAT_OUT2IN_NEXT_DROP;
1263                     }
1264                   goto trace00;
1265                 }
1266
1267               if (PREDICT_FALSE (identity_nat0))
1268                 goto trace00;
1269
1270               /* Create session initiated by host from external network */
1271               s0 = create_session_for_static_mapping (sm, b0, sm0, key0, node,
1272                                                       thread_index, now);
1273               if (!s0)
1274                 {
1275                   next0 = SNAT_OUT2IN_NEXT_DROP;
1276                   goto trace00;
1277                 }
1278             }
1279           else
1280             s0 =
1281               pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1282                                  value0.value);
1283
1284           old_addr0 = ip0->dst_address.as_u32;
1285           ip0->dst_address = s0->in2out.addr;
1286           new_addr0 = ip0->dst_address.as_u32;
1287           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1288
1289           sum0 = ip0->checksum;
1290           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1291                                  ip4_header_t,
1292                                  dst_address /* changed member */ );
1293           ip0->checksum = ip_csum_fold (sum0);
1294
1295           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1296             {
1297               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1298                 {
1299                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1300                   new_port0 = udp0->dst_port = s0->in2out.port;
1301
1302                   sum0 = tcp0->checksum;
1303                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1304                                          ip4_header_t,
1305                                          dst_address /* changed member */ );
1306
1307                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1308                                          ip4_header_t /* cheat */ ,
1309                                          length /* changed member */ );
1310                   tcp0->checksum = ip_csum_fold (sum0);
1311                 }
1312               tcp_packets++;
1313             }
1314           else
1315             {
1316               if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1317                 {
1318                   old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1319                   new_port0 = udp0->dst_port = s0->in2out.port;
1320                   if (PREDICT_FALSE (udp0->checksum))
1321                     {
1322                       sum0 = udp0->checksum;
1323                       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address      /* changed member */
1324                         );
1325                       sum0 =
1326                         ip_csum_update (sum0, old_port0, new_port0,
1327                                         ip4_header_t /* cheat */ ,
1328                                         length /* changed member */ );
1329                       udp0->checksum = ip_csum_fold (sum0);
1330                     }
1331                 }
1332               udp_packets++;
1333             }
1334
1335           /* Accounting */
1336           nat44_session_update_counters (s0, now,
1337                                          vlib_buffer_length_in_chain (vm, b0),
1338                                          thread_index);
1339           /* Per-user LRU list maintenance */
1340           nat44_session_update_lru (sm, s0, thread_index);
1341         trace00:
1342
1343           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1344                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1345             {
1346               snat_out2in_trace_t *t =
1347                 vlib_add_trace (vm, node, b0, sizeof (*t));
1348               t->sw_if_index = sw_if_index0;
1349               t->next_index = next0;
1350               t->session_index = ~0;
1351               if (s0)
1352                 t->session_index =
1353                   s0 - sm->per_thread_data[thread_index].sessions;
1354             }
1355
1356           pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
1357
1358           /* verify speculative enqueue, maybe switch current next frame */
1359           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1360                                            to_next, n_left_to_next,
1361                                            bi0, next0);
1362         }
1363
1364       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1365     }
1366
1367   vlib_node_increment_counter (vm, sm->out2in_node_index,
1368                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1369                                pkts_processed);
1370   vlib_node_increment_counter (vm, sm->out2in_node_index,
1371                                SNAT_OUT2IN_ERROR_TCP_PACKETS, tcp_packets);
1372   vlib_node_increment_counter (vm, sm->out2in_node_index,
1373                                SNAT_OUT2IN_ERROR_UDP_PACKETS, udp_packets);
1374   vlib_node_increment_counter (vm, sm->out2in_node_index,
1375                                SNAT_OUT2IN_ERROR_ICMP_PACKETS, icmp_packets);
1376   vlib_node_increment_counter (vm, sm->out2in_node_index,
1377                                SNAT_OUT2IN_ERROR_OTHER_PACKETS,
1378                                other_packets);
1379   vlib_node_increment_counter (vm, sm->out2in_node_index,
1380                                SNAT_OUT2IN_ERROR_FRAGMENTS, fragments);
1381
1382   return frame->n_vectors;
1383 }
1384
1385 /* *INDENT-OFF* */
1386 VLIB_REGISTER_NODE (snat_out2in_node) = {
1387   .name = "nat44-out2in",
1388   .vector_size = sizeof (u32),
1389   .format_trace = format_snat_out2in_trace,
1390   .type = VLIB_NODE_TYPE_INTERNAL,
1391
1392   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1393   .error_strings = snat_out2in_error_strings,
1394
1395   .runtime_data_bytes = sizeof (snat_runtime_t),
1396
1397   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1398
1399   /* edit / add dispositions here */
1400   .next_nodes = {
1401     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1402     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1403     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1404   },
1405 };
1406 /* *INDENT-ON* */
1407
1408 VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
1409                                       vlib_node_runtime_t * node,
1410                                       vlib_frame_t * frame)
1411 {
1412   u32 n_left_from, *from, *to_next;
1413   snat_out2in_next_t next_index;
1414   u32 pkts_processed = 0;
1415   snat_main_t *sm = &snat_main;
1416
1417   from = vlib_frame_vector_args (frame);
1418   n_left_from = frame->n_vectors;
1419   next_index = node->cached_next_index;
1420
1421   while (n_left_from > 0)
1422     {
1423       u32 n_left_to_next;
1424
1425       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1426
1427       while (n_left_from > 0 && n_left_to_next > 0)
1428         {
1429           u32 bi0;
1430           vlib_buffer_t *b0;
1431           u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1432           u32 sw_if_index0;
1433           ip4_header_t *ip0;
1434           ip_csum_t sum0;
1435           u32 new_addr0, old_addr0;
1436           u16 new_port0, old_port0;
1437           udp_header_t *udp0;
1438           tcp_header_t *tcp0;
1439           icmp46_header_t *icmp0;
1440           snat_session_key_t key0, sm0;
1441           u32 proto0;
1442           u32 rx_fib_index0;
1443
1444           /* speculatively enqueue b0 to the current next frame */
1445           bi0 = from[0];
1446           to_next[0] = bi0;
1447           from += 1;
1448           to_next += 1;
1449           n_left_from -= 1;
1450           n_left_to_next -= 1;
1451
1452           b0 = vlib_get_buffer (vm, bi0);
1453
1454           ip0 = vlib_buffer_get_current (b0);
1455           udp0 = ip4_next_header (ip0);
1456           tcp0 = (tcp_header_t *) udp0;
1457           icmp0 = (icmp46_header_t *) udp0;
1458
1459           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1460           rx_fib_index0 =
1461             ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1462
1463           vnet_feature_next (&next0, b0);
1464
1465           if (PREDICT_FALSE (ip0->ttl == 1))
1466             {
1467               vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1468               icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1469                                            ICMP4_time_exceeded_ttl_exceeded_in_transit,
1470                                            0);
1471               next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1472               goto trace00;
1473             }
1474
1475           proto0 = ip_proto_to_nat_proto (ip0->protocol);
1476
1477           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1478             goto trace00;
1479
1480           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1481             {
1482               next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1483                                    rx_fib_index0, node, next0, ~0, 0, 0);
1484               goto trace00;
1485             }
1486
1487           key0.addr = ip0->dst_address;
1488           key0.port = udp0->dst_port;
1489           key0.fib_index = rx_fib_index0;
1490
1491           if (snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0, 0))
1492             {
1493               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1494               goto trace00;
1495             }
1496
1497           new_addr0 = sm0.addr.as_u32;
1498           new_port0 = sm0.port;
1499           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
1500           old_addr0 = ip0->dst_address.as_u32;
1501           ip0->dst_address.as_u32 = new_addr0;
1502
1503           sum0 = ip0->checksum;
1504           sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1505                                  ip4_header_t,
1506                                  dst_address /* changed member */ );
1507           ip0->checksum = ip_csum_fold (sum0);
1508
1509           if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1510             {
1511               old_port0 = udp0->dst_port;
1512               udp0->dst_port = new_port0;
1513
1514               if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1515                 {
1516                   sum0 = tcp0->checksum;
1517                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1518                                          ip4_header_t,
1519                                          dst_address /* changed member */ );
1520                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1521                                          ip4_header_t /* cheat */ ,
1522                                          length /* changed member */ );
1523                   tcp0->checksum = ip_csum_fold (sum0);
1524                 }
1525               else if (udp0->checksum)
1526                 {
1527                   sum0 = udp0->checksum;
1528                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1529                                          ip4_header_t,
1530                                          dst_address /* changed member */ );
1531                   sum0 = ip_csum_update (sum0, old_port0, new_port0,
1532                                          ip4_header_t /* cheat */ ,
1533                                          length /* changed member */ );
1534                   udp0->checksum = ip_csum_fold (sum0);
1535                 }
1536             }
1537           else
1538             {
1539               if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1540                 {
1541                   sum0 = tcp0->checksum;
1542                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1543                                          ip4_header_t,
1544                                          dst_address /* changed member */ );
1545                   tcp0->checksum = ip_csum_fold (sum0);
1546                 }
1547               else if (udp0->checksum)
1548                 {
1549                   sum0 = udp0->checksum;
1550                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1551                                          ip4_header_t,
1552                                          dst_address /* changed member */ );
1553                   udp0->checksum = ip_csum_fold (sum0);
1554                 }
1555             }
1556
1557         trace00:
1558
1559           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1560                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1561             {
1562               snat_out2in_trace_t *t =
1563                 vlib_add_trace (vm, node, b0, sizeof (*t));
1564               t->sw_if_index = sw_if_index0;
1565               t->next_index = next0;
1566             }
1567
1568           pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1569
1570           /* verify speculative enqueue, maybe switch current next frame */
1571           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
1572                                            to_next, n_left_to_next,
1573                                            bi0, next0);
1574         }
1575
1576       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1577     }
1578
1579   vlib_node_increment_counter (vm, sm->out2in_fast_node_index,
1580                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1581                                pkts_processed);
1582   return frame->n_vectors;
1583 }
1584
1585 /* *INDENT-OFF* */
1586 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1587   .name = "nat44-out2in-fast",
1588   .vector_size = sizeof (u32),
1589   .format_trace = format_snat_out2in_fast_trace,
1590   .type = VLIB_NODE_TYPE_INTERNAL,
1591
1592   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1593   .error_strings = snat_out2in_error_strings,
1594
1595   .runtime_data_bytes = sizeof (snat_runtime_t),
1596
1597   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1598
1599   /* edit / add dispositions here */
1600   .next_nodes = {
1601     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1602     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1603     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1604   },
1605 };
1606 /* *INDENT-ON* */
1607
1608 /*
1609  * fd.io coding-style-patch-verification: ON
1610  *
1611  * Local Variables:
1612  * eval: (c-set-style "gnu")
1613  * End:
1614  */