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 _(CANNOT_CREATE_USER, "cannot create NAT user")
  89
  90 typedef enum
  91 {
  92 #define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
  93   foreach_snat_out2in_error
  94 #undef _
  95     SNAT_OUT2IN_N_ERROR,
  96 } snat_out2in_error_t;
  97
  98 static char *snat_out2in_error_strings[] = {
  99 #define _(sym,string) string,
 100   foreach_snat_out2in_error
 101 #undef _
 102 };
 103
 104 typedef enum
 105 {
 106   SNAT_OUT2IN_NEXT_DROP,
 107   SNAT_OUT2IN_NEXT_LOOKUP,
 108   SNAT_OUT2IN_NEXT_ICMP_ERROR,
 109   SNAT_OUT2IN_N_NEXT,
 110 } snat_out2in_next_t;
 111
 112 #ifndef CLIB_MARCH_VARIANT
 113 int
 114 nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 115 {
 116   snat_main_t *sm = &snat_main;
 117   nat44_is_idle_session_ctx_t *ctx = arg;
 118   snat_session_t *s;
 119   u64 sess_timeout_time;
 120   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
 121                                                        ctx->thread_index);
 122   clib_bihash_kv_8_8_t s_kv;
 123
 124   s = pool_elt_at_index (tsm->sessions, kv->value);
 125   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
 126   if (ctx->now >= sess_timeout_time)
 127     {
 128       init_nat_i2o_k (&s_kv, s);
 129       if (clib_bihash_add_del_8_8 (&tsm->in2out, &s_kv, 0))
 130         nat_elog_warn ("out2in key del failed");
 131
 132       snat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
 133                                            s->in2out.addr.as_u32,
 134                                            s->out2in.addr.as_u32,
 135                                            s->nat_proto,
 136                                            s->in2out.port,
 137                                            s->out2in.port,
 138                                            s->in2out.fib_index);
 139
 140       nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
 141                                &s->in2out.addr, s->in2out.port,
 142                                &s->out2in.addr, s->out2in.port, s->nat_proto);
 143
 144       nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
 145                    s->ext_host_port, s->nat_proto, s->out2in.fib_index,
 146                    ctx->thread_index);
 147
 148       if (!snat_is_session_static (s))
 149         snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
 150                                             &s->out2in.addr, s->out2in.port,
 151                                             s->nat_proto);
 152
 153       nat44_delete_session (sm, s, ctx->thread_index);
 154       return 1;
 155     }
 156
 157   return 0;
 158 }
 159 #endif
 160
 161 /**
 162  * @brief Create session for static mapping.
 163  *
 164  * Create NAT session initiated by host from external network with static
 165  * mapping.
 166  *
 167  * @param sm     NAT main.
 168  * @param b0     Vlib buffer.
 169  * @param in2out In2out NAT44 session key.
 170  * @param out2in Out2in NAT44 session key.
 171  * @param node   Vlib node.
 172  *
 173  * @returns SNAT session if successfully created otherwise 0.
 174  */
 175 static inline snat_session_t *
 176 create_session_for_static_mapping (snat_main_t * sm,
 177                                    vlib_buffer_t * b0,
 178                                    ip4_address_t i2o_addr,
 179                                    u16 i2o_port,
 180                                    u32 i2o_fib_index,
 181                                    ip4_address_t o2i_addr,
 182                                    u16 o2i_port,
 183                                    u32 o2i_fib_index,
 184                                    nat_protocol_t proto,
 185                                    vlib_node_runtime_t * node,
 186                                    u32 thread_index, f64 now)
 187 {
 188   snat_user_t *u;
 189   snat_session_t *s;
 190   clib_bihash_kv_8_8_t kv0;
 191   ip4_header_t *ip0;
 192   udp_header_t *udp0;
 193   nat44_is_idle_session_ctx_t ctx0;
 194
 195   if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
 196     {
 197       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
 198       nat_elog_notice ("maximum sessions exceeded");
 199       return 0;
 200     }
 201
 202   ip0 = vlib_buffer_get_current (b0);
 203   udp0 = ip4_next_header (ip0);
 204
 205   u = nat_user_get_or_create (sm, &i2o_addr, i2o_fib_index, thread_index);
 206   if (!u)
 207     {
 208       b0->error = node->errors[SNAT_OUT2IN_ERROR_CANNOT_CREATE_USER];
 209       return 0;
 210     }
 211
 212   s = nat_session_alloc_or_recycle (sm, u, thread_index, now);
 213   if (!s)
 214     {
 215       nat44_delete_user_with_no_session (sm, u, thread_index);
 216       nat_elog_warn ("create NAT session failed");
 217       return 0;
 218     }
 219
 220   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 221   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
 222   s->ext_host_port = udp0->src_port;
 223   user_session_increment (sm, u, 1 /* static */ );
 224   s->in2out.addr = i2o_addr;
 225   s->in2out.port = i2o_port;
 226   s->in2out.fib_index = i2o_fib_index;
 227   s->out2in.addr = o2i_addr;
 228   s->out2in.port = o2i_port;
 229   s->out2in.fib_index = o2i_fib_index;
 230   s->nat_proto = proto;
 231
 232   /* Add to translation hashes */
 233   ctx0.now = now;
 234   ctx0.thread_index = thread_index;
 235   init_nat_i2o_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
 236   if (clib_bihash_add_or_overwrite_stale_8_8
 237       (&sm->per_thread_data[thread_index].in2out, &kv0,
 238        nat44_i2o_is_idle_session_cb, &ctx0))
 239     nat_elog_notice ("in2out key add failed");
 240
 241   init_nat_o2i_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
 242   if (clib_bihash_add_or_overwrite_stale_8_8
 243       (&sm->per_thread_data[thread_index].out2in, &kv0,
 244        nat44_o2i_is_idle_session_cb, &ctx0))
 245     nat_elog_notice ("out2in key add failed");
 246
 247   /* log NAT event */
 248   snat_ipfix_logging_nat44_ses_create (thread_index,
 249                                        s->in2out.addr.as_u32,
 250                                        s->out2in.addr.as_u32,
 251                                        s->nat_proto,
 252                                        s->in2out.port,
 253                                        s->out2in.port, s->in2out.fib_index);
 254
 255   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
 256                            &s->in2out.addr, s->in2out.port, &s->out2in.addr,
 257                            s->out2in.port, s->nat_proto);
 258
 259   nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
 260                s->out2in.port, &s->ext_host_addr, s->ext_host_port,
 261                &s->ext_host_nat_addr, s->ext_host_nat_port,
 262                s->nat_proto, s->in2out.fib_index, s->flags, thread_index, 0);
 263
 264   return s;
 265 }
 266
 267 #ifndef CLIB_MARCH_VARIANT
 268 static_always_inline snat_out2in_error_t
 269 icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
 270               ip4_address_t * addr, u16 * port, nat_protocol_t * nat_proto)
 271 {
 272   icmp46_header_t *icmp0;
 273   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 274   ip4_header_t *inner_ip0;
 275   void *l4_header = 0;
 276   icmp46_header_t *inner_icmp0;
 277
 278   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
 279   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 280
 281   if (!icmp_type_is_error_message
 282       (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
 283     {
 284       *nat_proto = NAT_PROTOCOL_ICMP;
 285       *addr = ip0->dst_address;
 286       *port = vnet_buffer (b)->ip.reass.l4_src_port;
 287     }
 288   else
 289     {
 290       inner_ip0 = (ip4_header_t *) (echo0 + 1);
 291       l4_header = ip4_next_header (inner_ip0);
 292       *nat_proto = ip_proto_to_nat_proto (inner_ip0->protocol);
 293       *addr = inner_ip0->src_address;
 294       switch (*nat_proto)
 295         {
 296         case NAT_PROTOCOL_ICMP:
 297           inner_icmp0 = (icmp46_header_t *) l4_header;
 298           inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 299           *port = inner_echo0->identifier;
 300           break;
 301         case NAT_PROTOCOL_UDP:
 302         case NAT_PROTOCOL_TCP:
 303           *port = ((tcp_udp_header_t *) l4_header)->src_port;
 304           break;
 305         default:
 306           return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
 307         }
 308     }
 309   return -1;                    /* success */
 310 }
 311
 312 /**
 313  * Get address and port values to be used for ICMP packet translation
 314  * and create session if needed
 315  *
 316  * @param[in,out] sm             NAT main
 317  * @param[in,out] node           NAT node runtime
 318  * @param[in] thread_index       thread index
 319  * @param[in,out] b0             buffer containing packet to be translated
 320  * @param[in,out] ip0            ip header
 321  * @param[out] p_proto           protocol used for matching
 322  * @param[out] p_value           address and port after NAT translation
 323  * @param[out] p_dont_translate  if packet should not be translated
 324  * @param d                      optional parameter
 325  * @param e                      optional parameter
 326  */
 327 u32
 328 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 329                         u32 thread_index, vlib_buffer_t * b0,
 330                         ip4_header_t * ip0, ip4_address_t * addr,
 331                         u16 * port, u32 * fib_index,
 332                         nat_protocol_t * proto, void *d, void *e,
 333                         u8 * dont_translate)
 334 {
 335   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 336   u32 sw_if_index0;
 337   snat_session_t *s0 = 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   vlib_main_t *vm = vlib_get_main ();
 344   *dont_translate = 0;
 345
 346   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 347   *fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 348
 349   *proto = 0;
 350
 351   err = icmp_get_key (b0, ip0, addr, port, proto);
 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
 359   ip4_address_t mapping_addr;
 360   u16 mapping_port;
 361   u32 mapping_fib_index;
 362
 363   init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
 364   if (clib_bihash_search_8_8 (&tsm->out2in, &kv0, &value0))
 365     {
 366       /* Try to match static mapping by external address and port,
 367          destination address and port in packet */
 368       if (snat_static_mapping_match
 369           (sm, *addr, *port, *fib_index, *proto,
 370            &mapping_addr, &mapping_port, &mapping_fib_index, 1, &is_addr_only,
 371            0, 0, 0, &identity_nat))
 372         {
 373           if (!sm->forwarding_enabled)
 374             {
 375               /* Don't NAT packet aimed at the intfc address */
 376               if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
 377                                                     ip0->dst_address.as_u32)))
 378                 {
 379                   *dont_translate = 1;
 380                   goto out;
 381                 }
 382               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 383               next0 = SNAT_OUT2IN_NEXT_DROP;
 384               goto out;
 385             }
 386           else
 387             {
 388               *dont_translate = 1;
 389               goto out;
 390             }
 391         }
 392
 393       if (PREDICT_FALSE
 394           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 395            ICMP4_echo_reply
 396            && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 397                ICMP4_echo_request || !is_addr_only)))
 398         {
 399           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 400           next0 = SNAT_OUT2IN_NEXT_DROP;
 401           goto out;
 402         }
 403
 404       if (PREDICT_FALSE (identity_nat))
 405         {
 406           *dont_translate = 1;
 407           goto out;
 408         }
 409       /* Create session initiated by host from external network */
 410       s0 =
 411         create_session_for_static_mapping (sm, b0, mapping_addr, mapping_port,
 412                                            mapping_fib_index, *addr, *port,
 413                                            *fib_index, *proto, node,
 414                                            thread_index, vlib_time_now (vm));
 415
 416       if (!s0)
 417         {
 418           next0 = SNAT_OUT2IN_NEXT_DROP;
 419           goto out;
 420         }
 421     }
 422   else
 423     {
 424       if (PREDICT_FALSE
 425           (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 426            ICMP4_echo_reply
 427            && vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 428            ICMP4_echo_request
 429            && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 430                                            reass.icmp_type_or_tcp_flags)))
 431         {
 432           b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 433           next0 = SNAT_OUT2IN_NEXT_DROP;
 434           goto out;
 435         }
 436
 437       s0 = pool_elt_at_index (tsm->sessions, value0.value);
 438     }
 439
 440 out:
 441   if (s0)
 442     {
 443       *addr = s0->in2out.addr;
 444       *port = s0->in2out.port;
 445       *fib_index = s0->in2out.fib_index;
 446     }
 447   if (d)
 448     *(snat_session_t **) d = s0;
 449   return next0;
 450 }
 451 #endif
 452
 453 #ifndef CLIB_MARCH_VARIANT
 454 /**
 455  * Get address and port values to be used for ICMP packet translation
 456  *
 457  * @param[in] sm                 NAT main
 458  * @param[in,out] node           NAT node runtime
 459  * @param[in] thread_index       thread index
 460  * @param[in,out] b0             buffer containing packet to be translated
 461  * @param[in,out] ip0            ip header
 462  * @param[out] p_proto           protocol used for matching
 463  * @param[out] p_value           address and port after NAT translation
 464  * @param[out] p_dont_translate  if packet should not be translated
 465  * @param d                      optional parameter
 466  * @param e                      optional parameter
 467  */
 468 u32
 469 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
 470                         u32 thread_index, vlib_buffer_t * b0,
 471                         ip4_header_t * ip0, ip4_address_t * mapping_addr,
 472                         u16 * mapping_port, u32 * mapping_fib_index,
 473                         nat_protocol_t * proto, void *d, void *e,
 474                         u8 * dont_translate)
 475 {
 476   u32 sw_if_index0;
 477   u32 rx_fib_index0;
 478   u8 is_addr_only;
 479   u32 next0 = ~0;
 480   int err;
 481   ip4_address_t addr;
 482   u16 port;
 483   *dont_translate = 0;
 484
 485   sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 486   rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 487
 488   err = icmp_get_key (b0, ip0, &addr, &port, proto);
 489   if (err != -1)
 490     {
 491       b0->error = node->errors[err];
 492       next0 = SNAT_OUT2IN_NEXT_DROP;
 493       goto out;
 494     }
 495   if (snat_static_mapping_match
 496       (sm, addr, port, rx_fib_index0, *proto, mapping_addr, mapping_port,
 497        mapping_fib_index, 1, &is_addr_only, 0, 0, 0, 0))
 498     {
 499       /* Don't NAT packet aimed at the intfc address */
 500       if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
 501         {
 502           *dont_translate = 1;
 503           goto out;
 504         }
 505       b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 506       next0 = SNAT_OUT2IN_NEXT_DROP;
 507       goto out;
 508     }
 509
 510   if (PREDICT_FALSE
 511       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
 512        && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 513            ICMP4_echo_request || !is_addr_only)
 514        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 515                                        reass.icmp_type_or_tcp_flags)))
 516     {
 517       b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
 518       next0 = SNAT_OUT2IN_NEXT_DROP;
 519       goto out;
 520     }
 521
 522 out:
 523   return next0;
 524 }
 525 #endif
 526
 527 #ifndef CLIB_MARCH_VARIANT
 528 u32
 529 icmp_out2in (snat_main_t * sm,
 530              vlib_buffer_t * b0,
 531              ip4_header_t * ip0,
 532              icmp46_header_t * icmp0,
 533              u32 sw_if_index0,
 534              u32 rx_fib_index0,
 535              vlib_node_runtime_t * node,
 536              u32 next0, u32 thread_index, void *d, void *e)
 537 {
 538   icmp_echo_header_t *echo0, *inner_echo0 = 0;
 539   ip4_header_t *inner_ip0 = 0;
 540   void *l4_header = 0;
 541   icmp46_header_t *inner_icmp0;
 542   u8 dont_translate;
 543   u32 new_addr0, old_addr0;
 544   u16 old_id0, new_id0;
 545   ip_csum_t sum0;
 546   u16 checksum0;
 547   u32 next0_tmp;
 548   vlib_main_t *vm = vlib_get_main ();
 549   ip4_address_t addr;
 550   u16 port;
 551   u32 fib_index;
 552   nat_protocol_t proto;
 553
 554   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 555
 556   next0_tmp = sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0,
 557                                         &addr, &port, &fib_index, &proto,
 558                                         d, e, &dont_translate);
 559   if (next0_tmp != ~0)
 560     next0 = next0_tmp;
 561   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
 562     goto out;
 563
 564   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
 565     {
 566       sum0 =
 567         ip_incremental_checksum_buffer (vm, b0,
 568                                         (u8 *) icmp0 -
 569                                         (u8 *) vlib_buffer_get_current (b0),
 570                                         ntohs (ip0->length) -
 571                                         ip4_header_bytes (ip0), 0);
 572       checksum0 = ~ip_csum_fold (sum0);
 573       if (checksum0 != 0 && checksum0 != 0xffff)
 574         {
 575           next0 = SNAT_OUT2IN_NEXT_DROP;
 576           goto out;
 577         }
 578     }
 579
 580   old_addr0 = ip0->dst_address.as_u32;
 581   new_addr0 = ip0->dst_address.as_u32 = addr.as_u32;
 582   vnet_buffer (b0)->sw_if_index[VLIB_TX] = fib_index;
 583
 584   sum0 = ip0->checksum;
 585   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 586                          dst_address /* changed member */ );
 587   ip0->checksum = ip_csum_fold (sum0);
 588
 589
 590   if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 591     {
 592       if (icmp0->checksum == 0)
 593         icmp0->checksum = 0xffff;
 594
 595       if (!icmp_type_is_error_message (icmp0->type))
 596         {
 597           new_id0 = port;
 598           if (PREDICT_FALSE (new_id0 != echo0->identifier))
 599             {
 600               old_id0 = echo0->identifier;
 601               new_id0 = port;
 602               echo0->identifier = new_id0;
 603
 604               sum0 = icmp0->checksum;
 605               sum0 =
 606                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 607                                 identifier /* changed member */ );
 608               icmp0->checksum = ip_csum_fold (sum0);
 609             }
 610         }
 611       else
 612         {
 613           inner_ip0 = (ip4_header_t *) (echo0 + 1);
 614           l4_header = ip4_next_header (inner_ip0);
 615
 616           if (!ip4_header_checksum_is_valid (inner_ip0))
 617             {
 618               next0 = SNAT_OUT2IN_NEXT_DROP;
 619               goto out;
 620             }
 621
 622           old_addr0 = inner_ip0->src_address.as_u32;
 623           inner_ip0->src_address = addr;
 624           new_addr0 = inner_ip0->src_address.as_u32;
 625
 626           sum0 = icmp0->checksum;
 627           sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 628                                  src_address /* changed member */ );
 629           icmp0->checksum = ip_csum_fold (sum0);
 630
 631           switch (proto)
 632             {
 633             case NAT_PROTOCOL_ICMP:
 634               inner_icmp0 = (icmp46_header_t *) l4_header;
 635               inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 636
 637               old_id0 = inner_echo0->identifier;
 638               new_id0 = port;
 639               inner_echo0->identifier = new_id0;
 640
 641               sum0 = icmp0->checksum;
 642               sum0 =
 643                 ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
 644                                 identifier);
 645               icmp0->checksum = ip_csum_fold (sum0);
 646               break;
 647             case NAT_PROTOCOL_UDP:
 648             case NAT_PROTOCOL_TCP:
 649               old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
 650               new_id0 = port;
 651               ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 652
 653               sum0 = icmp0->checksum;
 654               sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
 655                                      src_port);
 656               icmp0->checksum = ip_csum_fold (sum0);
 657               break;
 658             default:
 659               ASSERT (0);
 660             }
 661         }
 662     }
 663
 664 out:
 665   return next0;
 666 }
 667 #endif
 668
 669 static inline u32
 670 icmp_out2in_slow_path (snat_main_t * sm,
 671                        vlib_buffer_t * b0,
 672                        ip4_header_t * ip0,
 673                        icmp46_header_t * icmp0,
 674                        u32 sw_if_index0,
 675                        u32 rx_fib_index0,
 676                        vlib_node_runtime_t * node,
 677                        u32 next0, f64 now,
 678                        u32 thread_index, snat_session_t ** p_s0)
 679 {
 680   vlib_main_t *vm = vlib_get_main ();
 681
 682   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 683                        next0, thread_index, p_s0, 0);
 684   snat_session_t *s0 = *p_s0;
 685   if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
 686     {
 687       /* Accounting */
 688       nat44_session_update_counters (s0, now,
 689                                      vlib_buffer_length_in_chain
 690                                      (vm, b0), thread_index);
 691       /* Per-user LRU list maintenance */
 692       nat44_session_update_lru (sm, s0, thread_index);
 693     }
 694   return next0;
 695 }
 696
 697 static int
 698 nat_out2in_sm_unknown_proto (snat_main_t * sm,
 699                              vlib_buffer_t * b,
 700                              ip4_header_t * ip, u32 rx_fib_index)
 701 {
 702   clib_bihash_kv_8_8_t kv, value;
 703   snat_static_mapping_t *m;
 704   u32 old_addr, new_addr;
 705   ip_csum_t sum;
 706
 707   init_nat_k (&kv, ip->dst_address, 0, 0, 0);
 708   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 709     return 1;
 710
 711   m = pool_elt_at_index (sm->static_mappings, value.value);
 712
 713   old_addr = ip->dst_address.as_u32;
 714   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 715   sum = ip->checksum;
 716   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 717   ip->checksum = ip_csum_fold (sum);
 718
 719   vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 720   return 0;
 721 }
 722
 723 VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 724                                  vlib_node_runtime_t * node,
 725                                  vlib_frame_t * frame)
 726 {
 727   u32 n_left_from, *from;
 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
 739   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
 740   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 741   vlib_get_buffers (vm, from, b, n_left_from);
 742
 743   while (n_left_from >= 2)
 744     {
 745       vlib_buffer_t *b0, *b1;
 746       u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
 747       u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
 748       u32 sw_if_index0, sw_if_index1;
 749       ip4_header_t *ip0, *ip1;
 750       ip_csum_t sum0, sum1;
 751       u32 new_addr0, old_addr0;
 752       u16 new_port0, old_port0;
 753       u32 new_addr1, old_addr1;
 754       u16 new_port1, old_port1;
 755       udp_header_t *udp0, *udp1;
 756       tcp_header_t *tcp0, *tcp1;
 757       icmp46_header_t *icmp0, *icmp1;
 758       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       ip4_address_t sm_addr0, sm_addr1;
 764       u16 sm_port0, sm_port1;
 765       u32 sm_fib_index0, sm_fib_index1;
 766
 767       b0 = *b;
 768       b++;
 769       b1 = *b;
 770       b++;
 771
 772       /* Prefetch next iteration. */
 773       if (PREDICT_TRUE (n_left_from >= 4))
 774         {
 775           vlib_buffer_t *p2, *p3;
 776
 777           p2 = *b;
 778           p3 = *(b + 1);
 779
 780           vlib_prefetch_buffer_header (p2, LOAD);
 781           vlib_prefetch_buffer_header (p3, LOAD);
 782
 783           CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
 784           CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
 785         }
 786
 787       vnet_buffer (b0)->snat.flags = 0;
 788       vnet_buffer (b1)->snat.flags = 0;
 789
 790       ip0 = vlib_buffer_get_current (b0);
 791       udp0 = ip4_next_header (ip0);
 792       tcp0 = (tcp_header_t *) udp0;
 793       icmp0 = (icmp46_header_t *) udp0;
 794
 795       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 796       rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 797                                sw_if_index0);
 798
 799       if (PREDICT_FALSE (ip0->ttl == 1))
 800         {
 801           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 802           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 803                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 804                                        0);
 805           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 806           goto trace0;
 807         }
 808
 809       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 810
 811       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 812         {
 813           if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
 814             {
 815               if (!sm->forwarding_enabled)
 816                 {
 817                   b0->error =
 818                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 819                   next0 = SNAT_OUT2IN_NEXT_DROP;
 820                 }
 821             }
 822           other_packets++;
 823           goto trace0;
 824         }
 825
 826       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 827         {
 828           next0 = icmp_out2in_slow_path
 829             (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
 830              next0, now, thread_index, &s0);
 831           icmp_packets++;
 832           goto trace0;
 833         }
 834
 835       init_nat_k (&kv0, ip0->dst_address,
 836                   vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 837                   proto0);
 838       if (clib_bihash_search_8_8
 839           (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
 840         {
 841           /* Try to match static mapping by external address and port,
 842              destination address and port in packet */
 843           if (snat_static_mapping_match
 844               (sm, ip0->dst_address,
 845                vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 846                proto0, &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
 847                0, &identity_nat0))
 848             {
 849               /*
 850                * Send DHCP packets to the ipv4 stack, or we won't
 851                * be able to use dhcp client on the outside interface
 852                */
 853               if (PREDICT_FALSE
 854                   (proto0 == NAT_PROTOCOL_UDP
 855                    && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
 856                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
 857                 {
 858                   vnet_feature_next (&next0, b0);
 859                   goto trace0;
 860                 }
 861
 862               if (!sm->forwarding_enabled)
 863                 {
 864                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
 865                   next0 = SNAT_OUT2IN_NEXT_DROP;
 866                 }
 867               goto trace0;
 868             }
 869
 870           if (PREDICT_FALSE (identity_nat0))
 871             goto trace0;
 872
 873           /* Create session initiated by host from external network */
 874           s0 = create_session_for_static_mapping (sm, b0,
 875                                                   sm_addr0, sm_port0,
 876                                                   sm_fib_index0,
 877                                                   ip0->dst_address,
 878                                                   vnet_buffer (b0)->ip.
 879                                                   reass.l4_dst_port,
 880                                                   rx_fib_index0, proto0, node,
 881                                                   thread_index, now);
 882           if (!s0)
 883             {
 884               next0 = SNAT_OUT2IN_NEXT_DROP;
 885               goto trace0;
 886             }
 887         }
 888       else
 889         s0 = pool_elt_at_index (tsm->sessions, value0.value);
 890
 891       old_addr0 = ip0->dst_address.as_u32;
 892       ip0->dst_address = s0->in2out.addr;
 893       new_addr0 = ip0->dst_address.as_u32;
 894       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 895
 896       sum0 = ip0->checksum;
 897       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 898                              ip4_header_t, dst_address /* changed member */ );
 899       ip0->checksum = ip_csum_fold (sum0);
 900
 901       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 902         {
 903           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 904             {
 905               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 906               new_port0 = udp0->dst_port = s0->in2out.port;
 907               sum0 = tcp0->checksum;
 908               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 909                                      ip4_header_t,
 910                                      dst_address /* changed member */ );
 911
 912               sum0 = ip_csum_update (sum0, old_port0, new_port0,
 913                                      ip4_header_t /* cheat */ ,
 914                                      length /* changed member */ );
 915               tcp0->checksum = ip_csum_fold (sum0);
 916             }
 917           tcp_packets++;
 918         }
 919       else
 920         {
 921           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
 922             {
 923               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 924               new_port0 = udp0->dst_port = s0->in2out.port;
 925               if (PREDICT_FALSE (udp0->checksum))
 926                 {
 927                   sum0 = udp0->checksum;
 928                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
 929                     );
 930                   sum0 =
 931                     ip_csum_update (sum0, old_port0, new_port0,
 932                                     ip4_header_t /* cheat */ ,
 933                                     length /* changed member */ );
 934                   udp0->checksum = ip_csum_fold (sum0);
 935                 }
 936             }
 937           udp_packets++;
 938         }
 939
 940       /* Accounting */
 941       nat44_session_update_counters (s0, now,
 942                                      vlib_buffer_length_in_chain (vm, b0),
 943                                      thread_index);
 944       /* Per-user LRU list maintenance */
 945       nat44_session_update_lru (sm, s0, thread_index);
 946     trace0:
 947
 948       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 949                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 950         {
 951           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
 952           t->sw_if_index = sw_if_index0;
 953           t->next_index = next0;
 954           t->session_index = ~0;
 955           if (s0)
 956             t->session_index =
 957               s0 - sm->per_thread_data[thread_index].sessions;
 958         }
 959
 960       pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
 961
 962
 963       ip1 = vlib_buffer_get_current (b1);
 964       udp1 = ip4_next_header (ip1);
 965       tcp1 = (tcp_header_t *) udp1;
 966       icmp1 = (icmp46_header_t *) udp1;
 967
 968       sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
 969       rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
 970                                sw_if_index1);
 971
 972       if (PREDICT_FALSE (ip1->ttl == 1))
 973         {
 974           vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 975           icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 976                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
 977                                        0);
 978           next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
 979           goto trace1;
 980         }
 981
 982       proto1 = ip_proto_to_nat_proto (ip1->protocol);
 983
 984       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
 985         {
 986           if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
 987             {
 988               if (!sm->forwarding_enabled)
 989                 {
 990                   b1->error =
 991                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 992                   next1 = SNAT_OUT2IN_NEXT_DROP;
 993                 }
 994             }
 995           other_packets++;
 996           goto trace1;
 997         }
 998
 999       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
1000         {
1001           next1 = icmp_out2in_slow_path
1002             (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
1003              next1, now, thread_index, &s1);
1004           icmp_packets++;
1005           goto trace1;
1006         }
1007
1008       init_nat_k (&kv1, ip1->dst_address,
1009                   vnet_buffer (b1)->ip.reass.l4_dst_port, rx_fib_index1,
1010                   proto1);
1011
1012       if (clib_bihash_search_8_8
1013           (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
1014         {
1015           /* Try to match static mapping by external address and port,
1016              destination address and port in packet */
1017           if (snat_static_mapping_match
1018               (sm, ip1->dst_address,
1019                vnet_buffer (b1)->ip.reass.l4_dst_port, proto1,
1020                rx_fib_index1, &sm_addr1, &sm_port1, &sm_fib_index1, 1, 0,
1021                0, 0, 0, &identity_nat1))
1022             {
1023               /*
1024                * Send DHCP packets to the ipv4 stack, or we won't
1025                * be able to use dhcp client on the outside interface
1026                */
1027               if (PREDICT_FALSE
1028                   (proto1 == NAT_PROTOCOL_UDP
1029                    && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
1030                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
1031                 {
1032                   vnet_feature_next (&next1, b1);
1033                   goto trace1;
1034                 }
1035
1036               if (!sm->forwarding_enabled)
1037                 {
1038                   b1->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1039                   next1 = SNAT_OUT2IN_NEXT_DROP;
1040                 }
1041               goto trace1;
1042             }
1043
1044           if (PREDICT_FALSE (identity_nat1))
1045             goto trace1;
1046
1047           /* Create session initiated by host from external network */
1048           s1 =
1049             create_session_for_static_mapping (sm, b1, sm_addr1, sm_port1,
1050                                                sm_fib_index1,
1051                                                ip1->dst_address,
1052                                                vnet_buffer (b1)->ip.
1053                                                reass.l4_dst_port,
1054                                                rx_fib_index1, proto1, node,
1055                                                thread_index, now);
1056           if (!s1)
1057             {
1058               next1 = SNAT_OUT2IN_NEXT_DROP;
1059               goto trace1;
1060             }
1061         }
1062       else
1063         s1 =
1064           pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1065                              value1.value);
1066
1067       old_addr1 = ip1->dst_address.as_u32;
1068       ip1->dst_address = s1->in2out.addr;
1069       new_addr1 = ip1->dst_address.as_u32;
1070       vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
1071
1072       sum1 = ip1->checksum;
1073       sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
1074                              ip4_header_t, dst_address /* changed member */ );
1075       ip1->checksum = ip_csum_fold (sum1);
1076
1077       if (PREDICT_TRUE (proto1 == NAT_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 = vlib_add_trace (vm, node, b1, sizeof (*t));
1132           t->sw_if_index = sw_if_index1;
1133           t->next_index = next1;
1134           t->session_index = ~0;
1135           if (s1)
1136             t->session_index =
1137               s1 - sm->per_thread_data[thread_index].sessions;
1138         }
1139
1140       pkts_processed += next1 == SNAT_OUT2IN_NEXT_LOOKUP;
1141
1142       n_left_from -= 2;
1143       next[0] = next0;
1144       next[1] = next1;
1145       next += 2;
1146     }
1147
1148   while (n_left_from > 0)
1149     {
1150       vlib_buffer_t *b0;
1151       u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
1152       u32 sw_if_index0;
1153       ip4_header_t *ip0;
1154       ip_csum_t sum0;
1155       u32 new_addr0, old_addr0;
1156       u16 new_port0, old_port0;
1157       udp_header_t *udp0;
1158       tcp_header_t *tcp0;
1159       icmp46_header_t *icmp0;
1160       u32 rx_fib_index0;
1161       u32 proto0;
1162       snat_session_t *s0 = 0;
1163       clib_bihash_kv_8_8_t kv0, value0;
1164       u8 identity_nat0;
1165       ip4_address_t sm_addr0;
1166       u16 sm_port0;
1167       u32 sm_fib_index0;
1168
1169       b0 = *b;
1170       ++b;
1171
1172       vnet_buffer (b0)->snat.flags = 0;
1173
1174       ip0 = vlib_buffer_get_current (b0);
1175       udp0 = ip4_next_header (ip0);
1176       tcp0 = (tcp_header_t *) udp0;
1177       icmp0 = (icmp46_header_t *) udp0;
1178
1179       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1180       rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
1181                                sw_if_index0);
1182
1183       proto0 = ip_proto_to_nat_proto (ip0->protocol);
1184
1185       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1186         {
1187           if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
1188             {
1189               if (!sm->forwarding_enabled)
1190                 {
1191                   b0->error =
1192                     node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
1193                   next0 = SNAT_OUT2IN_NEXT_DROP;
1194                 }
1195             }
1196           other_packets++;
1197           goto trace00;
1198         }
1199
1200       if (PREDICT_FALSE (ip0->ttl == 1))
1201         {
1202           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1203           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1204                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
1205                                        0);
1206           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1207           goto trace00;
1208         }
1209
1210       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1211         {
1212           next0 = icmp_out2in_slow_path
1213             (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
1214              next0, now, thread_index, &s0);
1215           icmp_packets++;
1216           goto trace00;
1217         }
1218
1219       init_nat_k (&kv0, ip0->dst_address,
1220                   vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
1221                   proto0);
1222
1223       if (clib_bihash_search_8_8
1224           (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
1225         {
1226           /* Try to match static mapping by external address and port,
1227              destination address and port in packet */
1228           if (snat_static_mapping_match
1229               (sm, ip0->dst_address,
1230                vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
1231                proto0, &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
1232                0, &identity_nat0))
1233             {
1234               /*
1235                * Send DHCP packets to the ipv4 stack, or we won't
1236                * be able to use dhcp client on the outside interface
1237                */
1238               if (PREDICT_FALSE
1239                   (proto0 == NAT_PROTOCOL_UDP
1240                    && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
1241                        clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
1242                 {
1243                   vnet_feature_next (&next0, b0);
1244                   goto trace00;
1245                 }
1246
1247               if (!sm->forwarding_enabled)
1248                 {
1249                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1250                   next0 = SNAT_OUT2IN_NEXT_DROP;
1251                 }
1252               goto trace00;
1253             }
1254
1255           if (PREDICT_FALSE (identity_nat0))
1256             goto trace00;
1257
1258           /* Create session initiated by host from external network */
1259           s0 = create_session_for_static_mapping (sm, b0,
1260                                                   sm_addr0, sm_port0,
1261                                                   sm_fib_index0,
1262                                                   ip0->dst_address,
1263                                                   vnet_buffer (b0)->ip.
1264                                                   reass.l4_dst_port,
1265                                                   rx_fib_index0, proto0, node,
1266                                                   thread_index, now);
1267           if (!s0)
1268             {
1269               next0 = SNAT_OUT2IN_NEXT_DROP;
1270               goto trace00;
1271             }
1272         }
1273       else
1274         s0 =
1275           pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
1276                              value0.value);
1277
1278       old_addr0 = ip0->dst_address.as_u32;
1279       ip0->dst_address = s0->in2out.addr;
1280       new_addr0 = ip0->dst_address.as_u32;
1281       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
1282
1283       sum0 = ip0->checksum;
1284       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1285                              ip4_header_t, dst_address /* changed member */ );
1286       ip0->checksum = ip_csum_fold (sum0);
1287
1288       if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1289         {
1290           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1291             {
1292               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1293               new_port0 = udp0->dst_port = s0->in2out.port;
1294
1295               sum0 = tcp0->checksum;
1296               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1297                                      ip4_header_t,
1298                                      dst_address /* changed member */ );
1299
1300               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1301                                      ip4_header_t /* cheat */ ,
1302                                      length /* changed member */ );
1303               tcp0->checksum = ip_csum_fold (sum0);
1304             }
1305           tcp_packets++;
1306         }
1307       else
1308         {
1309           if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
1310             {
1311               old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
1312               new_port0 = udp0->dst_port = s0->in2out.port;
1313               if (PREDICT_FALSE (udp0->checksum))
1314                 {
1315                   sum0 = udp0->checksum;
1316                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
1317                     );
1318                   sum0 =
1319                     ip_csum_update (sum0, old_port0, new_port0,
1320                                     ip4_header_t /* cheat */ ,
1321                                     length /* changed member */ );
1322                   udp0->checksum = ip_csum_fold (sum0);
1323                 }
1324             }
1325           udp_packets++;
1326         }
1327
1328       /* Accounting */
1329       nat44_session_update_counters (s0, now,
1330                                      vlib_buffer_length_in_chain (vm, b0),
1331                                      thread_index);
1332       /* Per-user LRU list maintenance */
1333       nat44_session_update_lru (sm, s0, thread_index);
1334     trace00:
1335
1336       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1337                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1338         {
1339           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
1340           t->sw_if_index = sw_if_index0;
1341           t->next_index = next0;
1342           t->session_index = ~0;
1343           if (s0)
1344             t->session_index =
1345               s0 - sm->per_thread_data[thread_index].sessions;
1346         }
1347
1348       pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
1349
1350       n_left_from--;
1351       next[0] = next0;
1352       next++;
1353     }
1354
1355   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
1356                                frame->n_vectors);
1357
1358   vlib_node_increment_counter (vm, sm->out2in_node_index,
1359                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1360                                pkts_processed);
1361   vlib_node_increment_counter (vm, sm->out2in_node_index,
1362                                SNAT_OUT2IN_ERROR_TCP_PACKETS, tcp_packets);
1363   vlib_node_increment_counter (vm, sm->out2in_node_index,
1364                                SNAT_OUT2IN_ERROR_UDP_PACKETS, udp_packets);
1365   vlib_node_increment_counter (vm, sm->out2in_node_index,
1366                                SNAT_OUT2IN_ERROR_ICMP_PACKETS, icmp_packets);
1367   vlib_node_increment_counter (vm, sm->out2in_node_index,
1368                                SNAT_OUT2IN_ERROR_OTHER_PACKETS,
1369                                other_packets);
1370   vlib_node_increment_counter (vm, sm->out2in_node_index,
1371                                SNAT_OUT2IN_ERROR_FRAGMENTS, fragments);
1372
1373   return frame->n_vectors;
1374 }
1375
1376 /* *INDENT-OFF* */
1377 VLIB_REGISTER_NODE (snat_out2in_node) = {
1378   .name = "nat44-out2in",
1379   .vector_size = sizeof (u32),
1380   .format_trace = format_snat_out2in_trace,
1381   .type = VLIB_NODE_TYPE_INTERNAL,
1382
1383   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1384   .error_strings = snat_out2in_error_strings,
1385
1386   .runtime_data_bytes = sizeof (snat_runtime_t),
1387
1388   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1389
1390   /* edit / add dispositions here */
1391   .next_nodes = {
1392     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1393     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1394     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1395   },
1396 };
1397 /* *INDENT-ON* */
1398
1399 VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
1400                                       vlib_node_runtime_t * node,
1401                                       vlib_frame_t * frame)
1402 {
1403   u32 n_left_from, *from;
1404   u32 pkts_processed = 0;
1405   snat_main_t *sm = &snat_main;
1406
1407   from = vlib_frame_vector_args (frame);
1408   n_left_from = frame->n_vectors;
1409
1410   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
1411   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
1412   vlib_get_buffers (vm, from, b, n_left_from);
1413   while (n_left_from > 0)
1414     {
1415       vlib_buffer_t *b0;
1416       u32 next0 = SNAT_OUT2IN_NEXT_DROP;
1417       u32 sw_if_index0;
1418       ip4_header_t *ip0;
1419       ip_csum_t sum0;
1420       u32 new_addr0, old_addr0;
1421       u16 new_port0, old_port0;
1422       udp_header_t *udp0;
1423       tcp_header_t *tcp0;
1424       icmp46_header_t *icmp0;
1425       u32 proto0;
1426       u32 rx_fib_index0;
1427       ip4_address_t sm_addr0;
1428       u16 sm_port0;
1429       u32 sm_fib_index0;
1430
1431       b0 = *b;
1432       b++;
1433
1434       ip0 = vlib_buffer_get_current (b0);
1435       udp0 = ip4_next_header (ip0);
1436       tcp0 = (tcp_header_t *) udp0;
1437       icmp0 = (icmp46_header_t *) udp0;
1438
1439       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
1440       rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
1441
1442       vnet_feature_next (&next0, b0);
1443
1444       if (PREDICT_FALSE (ip0->ttl == 1))
1445         {
1446           vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
1447           icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
1448                                        ICMP4_time_exceeded_ttl_exceeded_in_transit,
1449                                        0);
1450           next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
1451           goto trace00;
1452         }
1453
1454       proto0 = ip_proto_to_nat_proto (ip0->protocol);
1455
1456       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
1457         goto trace00;
1458
1459       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
1460         {
1461           next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
1462                                rx_fib_index0, node, next0, ~0, 0, 0);
1463           goto trace00;
1464         }
1465
1466       if (snat_static_mapping_match
1467           (sm, ip0->dst_address, udp0->dst_port, rx_fib_index0, proto0,
1468            &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0, 0, 0))
1469         {
1470           b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
1471           goto trace00;
1472         }
1473
1474       new_addr0 = sm_addr0.as_u32;
1475       new_port0 = sm_port0;
1476       vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm_fib_index0;
1477       old_addr0 = ip0->dst_address.as_u32;
1478       ip0->dst_address.as_u32 = new_addr0;
1479
1480       sum0 = ip0->checksum;
1481       sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1482                              ip4_header_t, dst_address /* changed member */ );
1483       ip0->checksum = ip_csum_fold (sum0);
1484
1485       if (PREDICT_FALSE (new_port0 != udp0->dst_port))
1486         {
1487           old_port0 = udp0->dst_port;
1488           udp0->dst_port = new_port0;
1489
1490           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1491             {
1492               sum0 = tcp0->checksum;
1493               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1494                                      ip4_header_t,
1495                                      dst_address /* changed member */ );
1496               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1497                                      ip4_header_t /* cheat */ ,
1498                                      length /* changed member */ );
1499               tcp0->checksum = ip_csum_fold (sum0);
1500             }
1501           else if (udp0->checksum)
1502             {
1503               sum0 = udp0->checksum;
1504               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1505                                      ip4_header_t,
1506                                      dst_address /* changed member */ );
1507               sum0 = ip_csum_update (sum0, old_port0, new_port0,
1508                                      ip4_header_t /* cheat */ ,
1509                                      length /* changed member */ );
1510               udp0->checksum = ip_csum_fold (sum0);
1511             }
1512         }
1513       else
1514         {
1515           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
1516             {
1517               sum0 = tcp0->checksum;
1518               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1519                                      ip4_header_t,
1520                                      dst_address /* changed member */ );
1521               tcp0->checksum = ip_csum_fold (sum0);
1522             }
1523           else if (udp0->checksum)
1524             {
1525               sum0 = udp0->checksum;
1526               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
1527                                      ip4_header_t,
1528                                      dst_address /* changed member */ );
1529               udp0->checksum = ip_csum_fold (sum0);
1530             }
1531         }
1532
1533     trace00:
1534
1535       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
1536                          && (b0->flags & VLIB_BUFFER_IS_TRACED)))
1537         {
1538           snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
1539           t->sw_if_index = sw_if_index0;
1540           t->next_index = next0;
1541         }
1542
1543       pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
1544
1545       n_left_from--;
1546       next[0] = next0;
1547       next++;
1548     }
1549
1550   vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
1551                                frame->n_vectors);
1552
1553   vlib_node_increment_counter (vm, sm->out2in_fast_node_index,
1554                                SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
1555                                pkts_processed);
1556   return frame->n_vectors;
1557 }
1558
1559 /* *INDENT-OFF* */
1560 VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
1561   .name = "nat44-out2in-fast",
1562   .vector_size = sizeof (u32),
1563   .format_trace = format_snat_out2in_fast_trace,
1564   .type = VLIB_NODE_TYPE_INTERNAL,
1565
1566   .n_errors = ARRAY_LEN(snat_out2in_error_strings),
1567   .error_strings = snat_out2in_error_strings,
1568
1569   .runtime_data_bytes = sizeof (snat_runtime_t),
1570
1571   .n_next_nodes = SNAT_OUT2IN_N_NEXT,
1572
1573   /* edit / add dispositions here */
1574   .next_nodes = {
1575     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
1576     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
1577     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
1578   },
1579 };
1580 /* *INDENT-ON* */
1581
1582 /*
1583  * fd.io coding-style-patch-verification: ON
1584  *
1585  * Local Variables:
1586  * eval: (c-set-style "gnu")
1587  * End:
1588  */