src/plugins/nat/nat.h

   1
   2 /*
   3  * nat.h - NAT plugin definitions
   4  *
   5  * Copyright (c) 2016 Cisco and/or its affiliates.
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at:
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  */
  18 #ifndef __included_nat_h__
  19 #define __included_nat_h__
  20
  21 #include <vnet/vnet.h>
  22 #include <vnet/ip/ip.h>
  23 #include <vnet/ethernet/ethernet.h>
  24 #include <vnet/ip/icmp46_packet.h>
  25 #include <vnet/api_errno.h>
  26 #include <vppinfra/bihash_8_8.h>
  27 #include <vppinfra/bihash_16_8.h>
  28 #include <vppinfra/dlist.h>
  29 #include <vppinfra/error.h>
  30 #include <vlibapi/api.h>
  31 #include <vlib/log.h>
  32
  33
  34 #define SNAT_UDP_TIMEOUT 300
  35 #define SNAT_UDP_TIMEOUT_MIN 120
  36 #define SNAT_TCP_TRANSITORY_TIMEOUT 240
  37 #define SNAT_TCP_ESTABLISHED_TIMEOUT 7440
  38 #define SNAT_TCP_INCOMING_SYN 6
  39 #define SNAT_ICMP_TIMEOUT 60
  40
  41 #define NAT_FQ_NELTS 64
  42
  43 #define SNAT_FLAG_HAIRPINNING (1 << 0)
  44
  45 /* Key */
  46 typedef struct {
  47   union
  48   {
  49     struct
  50     {
  51       ip4_address_t addr;
  52       u16 port;
  53       u16 protocol:3,
  54         fib_index:13;
  55     };
  56     u64 as_u64;
  57   };
  58 } snat_session_key_t;
  59
  60 typedef struct {
  61   union
  62   {
  63     struct
  64     {
  65       ip4_address_t l_addr;
  66       ip4_address_t r_addr;
  67       u32 proto:8,
  68           fib_index:24;
  69       u16 l_port;
  70       u16 r_port;
  71     };
  72     u64 as_u64[2];
  73   };
  74 } nat_ed_ses_key_t;
  75
  76 typedef struct {
  77   union
  78   {
  79     struct
  80     {
  81       ip4_address_t ext_host_addr;
  82       u16 ext_host_port;
  83       u16 out_port;
  84     };
  85     u64 as_u64;
  86   };
  87 } snat_det_out_key_t;
  88
  89 typedef struct {
  90   union
  91   {
  92     struct
  93     {
  94       ip4_address_t addr;
  95       u32 fib_index;
  96     };
  97     u64 as_u64;
  98   };
  99 } snat_user_key_t;
 100
 101
 102 #define foreach_snat_protocol \
 103   _(UDP, 0, udp, "udp")       \
 104   _(TCP, 1, tcp, "tcp")       \
 105   _(ICMP, 2, icmp, "icmp")
 106
 107 typedef enum {
 108 #define _(N, i, n, s) SNAT_PROTOCOL_##N = i,
 109   foreach_snat_protocol
 110 #undef _
 111 } snat_protocol_t;
 112
 113
 114 #define foreach_snat_session_state          \
 115   _(0, UNKNOWN, "unknown")                 \
 116   _(1, UDP_ACTIVE, "udp-active")           \
 117   _(2, TCP_SYN_SENT, "tcp-syn-sent")       \
 118   _(3, TCP_ESTABLISHED, "tcp-established") \
 119   _(4, TCP_FIN_WAIT, "tcp-fin-wait")       \
 120   _(5, TCP_CLOSE_WAIT, "tcp-close-wait")   \
 121   _(6, TCP_CLOSING, "tcp-closing")         \
 122   _(7, TCP_LAST_ACK, "tcp-last-ack")       \
 123   _(8, TCP_CLOSED, "tcp-closed")           \
 124   _(9, ICMP_ACTIVE, "icmp-active")
 125
 126 typedef enum {
 127 #define _(v, N, s) SNAT_SESSION_##N = v,
 128   foreach_snat_session_state
 129 #undef _
 130 } snat_session_state_t;
 131
 132 #define NAT44_SES_I2O_FIN 1
 133 #define NAT44_SES_O2I_FIN 2
 134 #define NAT44_SES_I2O_FIN_ACK 4
 135 #define NAT44_SES_O2I_FIN_ACK 8
 136
 137 #define nat44_is_ses_closed(s) s->state == 0xf
 138
 139 #define SNAT_SESSION_FLAG_STATIC_MAPPING       1
 140 #define SNAT_SESSION_FLAG_UNKNOWN_PROTO        2
 141 #define SNAT_SESSION_FLAG_LOAD_BALANCING       4
 142 #define SNAT_SESSION_FLAG_TWICE_NAT            8
 143 #define SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT   16
 144 #define SNAT_SESSION_FLAG_FWD_BYPASS           32
 145
 146 #define NAT_INTERFACE_FLAG_IS_INSIDE 1
 147 #define NAT_INTERFACE_FLAG_IS_OUTSIDE 2
 148
 149 typedef CLIB_PACKED(struct {
 150   snat_session_key_t out2in;    /* 0-15 */
 151
 152   snat_session_key_t in2out;    /* 16-31 */
 153
 154   u32 flags;                    /* 32-35 */
 155
 156   /* per-user translations */
 157   u32 per_user_index;           /* 36-39 */
 158
 159   u32 per_user_list_head_index; /* 40-43 */
 160
 161   /* Last heard timer */
 162   f64 last_heard;               /* 44-51 */
 163
 164   u64 total_bytes;              /* 52-59 */
 165
 166   u32 total_pkts;               /* 60-63 */
 167
 168   /* Outside address */
 169   u32 outside_address_index;    /* 64-67 */
 170
 171   /* External host address and port */
 172   ip4_address_t ext_host_addr;  /* 68-71 */
 173   u16 ext_host_port;            /* 72-73 */
 174
 175   /* External hos address and port after translation */
 176   ip4_address_t ext_host_nat_addr; /* 74-77 */
 177   u16 ext_host_nat_port;           /* 78-79 */
 178
 179   /* TCP session state */
 180   u8 state;
 181   u32 i2o_fin_seq;
 182   u32 o2i_fin_seq;
 183 }) snat_session_t;
 184
 185
 186 typedef struct {
 187   ip4_address_t addr;
 188   u32 fib_index;
 189   u32 sessions_per_user_list_head_index;
 190   u32 nsessions;
 191   u32 nstaticsessions;
 192 } snat_user_t;
 193
 194 typedef struct {
 195   ip4_address_t addr;
 196   u32 fib_index;
 197 #define _(N, i, n, s) \
 198   u16 busy_##n##_ports; \
 199   u16 * busy_##n##_ports_per_thread; \
 200   uword * busy_##n##_port_bitmap;
 201   foreach_snat_protocol
 202 #undef _
 203 } snat_address_t;
 204
 205 typedef struct {
 206   u16 in_port;
 207   snat_det_out_key_t out;
 208   u8 state;
 209   u32 expire;
 210 } snat_det_session_t;
 211
 212 typedef struct {
 213   ip4_address_t in_addr;
 214   u8 in_plen;
 215   ip4_address_t out_addr;
 216   u8 out_plen;
 217   u32 sharing_ratio;
 218   u16 ports_per_host;
 219   u32 ses_num;
 220   /* vector of sessions */
 221   snat_det_session_t * sessions;
 222 } snat_det_map_t;
 223
 224 typedef struct {
 225   ip4_address_t addr;
 226   u16 port;
 227   u8 probability;
 228   u8 prefix;
 229 } nat44_lb_addr_port_t;
 230
 231 typedef enum {
 232   TWICE_NAT_DISABLED,
 233   TWICE_NAT,
 234   TWICE_NAT_SELF,
 235 } twice_nat_type_t;
 236
 237 typedef struct {
 238   ip4_address_t local_addr;
 239   ip4_address_t external_addr;
 240   u16 local_port;
 241   u16 external_port;
 242   u8 addr_only;
 243   twice_nat_type_t twice_nat;
 244   u8 out2in_only;
 245   u32 vrf_id;
 246   u32 fib_index;
 247   snat_protocol_t proto;
 248   u32 *workers;
 249   u8 *tag;
 250   nat44_lb_addr_port_t *locals;
 251 } snat_static_mapping_t;
 252
 253 typedef struct {
 254   u32 sw_if_index;
 255   u8 flags;
 256 } snat_interface_t;
 257
 258 typedef struct {
 259   ip4_address_t l_addr;
 260   u16 l_port;
 261   u16 e_port;
 262   u32 sw_if_index;
 263   u32 vrf_id;
 264   snat_protocol_t proto;
 265   int addr_only;
 266   int twice_nat;
 267   int is_add;
 268   u8 *tag;
 269 } snat_static_map_resolve_t;
 270
 271 typedef struct {
 272   /* Main lookup tables */
 273   clib_bihash_8_8_t out2in;
 274   clib_bihash_8_8_t in2out;
 275
 276   /* Endpoint dependent sessions lookup tables */
 277   clib_bihash_16_8_t out2in_ed;
 278   clib_bihash_16_8_t in2out_ed;
 279
 280   /* Find-a-user => src address lookup */
 281   clib_bihash_8_8_t user_hash;
 282
 283   /* User pool */
 284   snat_user_t * users;
 285
 286   /* Session pool */
 287   snat_session_t * sessions;
 288
 289   /* Pool of doubly-linked list elements */
 290   dlist_elt_t * list_pool;
 291
 292   u32 snat_thread_index;
 293 } snat_main_per_thread_data_t;
 294
 295 struct snat_main_s;
 296
 297 typedef u32 snat_icmp_match_function_t (struct snat_main_s *sm,
 298                                         vlib_node_runtime_t *node,
 299                                         u32 thread_index,
 300                                         vlib_buffer_t *b0,
 301                                         ip4_header_t *ip0,
 302                                         u8 *p_proto,
 303                                         snat_session_key_t *p_value,
 304                                         u8 *p_dont_translate,
 305                                         void *d,
 306                                         void *e);
 307
 308 typedef u32 (snat_get_worker_function_t) (ip4_header_t * ip, u32 rx_fib_index);
 309
 310 typedef int nat_alloc_out_addr_and_port_function_t (snat_address_t * addresses,
 311                                                     u32 fib_index,
 312                                                     u32 thread_index,
 313                                                     snat_session_key_t * k,
 314                                                     u32 * address_indexp,
 315                                                     u16 port_per_thread,
 316                                                     u32 snat_thread_index);
 317
 318 typedef struct snat_main_s {
 319   snat_icmp_match_function_t * icmp_match_in2out_cb;
 320   snat_icmp_match_function_t * icmp_match_out2in_cb;
 321
 322   u32 num_workers;
 323   u32 first_worker_index;
 324   u32 * workers;
 325   snat_get_worker_function_t * worker_in2out_cb;
 326   snat_get_worker_function_t * worker_out2in_cb;
 327   u16 port_per_thread;
 328   u32 num_snat_thread;
 329
 330   /* Per thread data */
 331   snat_main_per_thread_data_t * per_thread_data;
 332
 333   /* Find a static mapping by local */
 334   clib_bihash_8_8_t static_mapping_by_local;
 335
 336   /* Find a static mapping by external */
 337   clib_bihash_8_8_t static_mapping_by_external;
 338
 339   /* Static mapping pool */
 340   snat_static_mapping_t * static_mappings;
 341
 342   /* Interface pool */
 343   snat_interface_t * interfaces;
 344   snat_interface_t * output_feature_interfaces;
 345
 346   /* Vector of outside addresses */
 347   snat_address_t * addresses;
 348   nat_alloc_out_addr_and_port_function_t *alloc_addr_and_port;
 349   u8 psid_offset;
 350   u8 psid_length;
 351   u16 psid;
 352
 353   /* Vector of twice NAT addresses for extenal hosts */
 354   snat_address_t * twice_nat_addresses;
 355
 356   /* sw_if_indices whose intfc addresses should be auto-added */
 357   u32 * auto_add_sw_if_indices;
 358   u32 * auto_add_sw_if_indices_twice_nat;
 359
 360   /* vector of interface address static mappings to resolve. */
 361   snat_static_map_resolve_t *to_resolve;
 362
 363   /* Randomize port allocation order */
 364   u32 random_seed;
 365
 366   /* Worker handoff index */
 367   u32 fq_in2out_index;
 368   u32 fq_in2out_output_index;
 369   u32 fq_out2in_index;
 370
 371   /* in2out and out2in node index */
 372   u32 in2out_node_index;
 373   u32 in2out_output_node_index;
 374   u32 out2in_node_index;
 375   u32 error_node_index;
 376
 377   /* Deterministic NAT */
 378   snat_det_map_t * det_maps;
 379
 380   /* If forwarding is enabled */
 381   u8 forwarding_enabled;
 382
 383   /* Config parameters */
 384   u8 static_mapping_only;
 385   u8 static_mapping_connection_tracking;
 386   u8 deterministic;
 387   u8 out2in_dpo;
 388   u8 endpoint_dependent;
 389   u32 translation_buckets;
 390   u32 translation_memory_size;
 391   u32 max_translations;
 392   u32 user_buckets;
 393   u32 user_memory_size;
 394   u32 max_translations_per_user;
 395   u32 outside_vrf_id;
 396   u32 outside_fib_index;
 397   u32 inside_vrf_id;
 398   u32 inside_fib_index;
 399
 400   /* values of various timeouts */
 401   u32 udp_timeout;
 402   u32 tcp_established_timeout;
 403   u32 tcp_transitory_timeout;
 404   u32 icmp_timeout;
 405
 406   /* API message ID base */
 407   u16 msg_id_base;
 408
 409   /* log class */
 410   vlib_log_class_t log_class;
 411
 412   /* convenience */
 413   vlib_main_t * vlib_main;
 414   vnet_main_t * vnet_main;
 415   ip4_main_t * ip4_main;
 416   ip_lookup_main_t * ip4_lookup_main;
 417   api_main_t * api_main;
 418 } snat_main_t;
 419
 420 extern snat_main_t snat_main;
 421 extern vlib_node_registration_t snat_in2out_node;
 422 extern vlib_node_registration_t snat_in2out_output_node;
 423 extern vlib_node_registration_t snat_out2in_node;
 424 extern vlib_node_registration_t snat_in2out_fast_node;
 425 extern vlib_node_registration_t snat_out2in_fast_node;
 426 extern vlib_node_registration_t snat_in2out_worker_handoff_node;
 427 extern vlib_node_registration_t snat_in2out_output_worker_handoff_node;
 428 extern vlib_node_registration_t snat_out2in_worker_handoff_node;
 429 extern vlib_node_registration_t snat_det_in2out_node;
 430 extern vlib_node_registration_t snat_det_out2in_node;
 431 extern vlib_node_registration_t snat_hairpin_dst_node;
 432 extern vlib_node_registration_t snat_hairpin_src_node;
 433 extern vlib_node_registration_t nat44_ed_in2out_node;
 434 extern vlib_node_registration_t nat44_ed_in2out_output_node;
 435 extern vlib_node_registration_t nat44_ed_out2in_node;
 436 extern vlib_node_registration_t nat44_ed_hairpin_dst_node;
 437 extern vlib_node_registration_t nat44_ed_hairpin_src_node;
 438 extern vlib_node_registration_t nat44_ed_in2out_worker_handoff_node;
 439 extern vlib_node_registration_t nat44_ed_in2out_output_worker_handoff_node;
 440 extern vlib_node_registration_t nat44_ed_out2in_worker_handoff_node;
 441
 442 void snat_free_outside_address_and_port (snat_address_t * addresses,
 443                                          u32 thread_index,
 444                                          snat_session_key_t * k,
 445                                          u32 address_index);
 446
 447 int snat_alloc_outside_address_and_port (snat_address_t * addresses,
 448                                          u32 fib_index,
 449                                          u32 thread_index,
 450                                          snat_session_key_t * k,
 451                                          u32 * address_indexp,
 452                                          u16 port_per_thread,
 453                                          u32 snat_thread_index);
 454
 455 int snat_static_mapping_match (snat_main_t * sm,
 456                                snat_session_key_t match,
 457                                snat_session_key_t * mapping,
 458                                u8 by_external,
 459                                u8 *is_addr_only,
 460                                twice_nat_type_t *twice_nat,
 461                                u8 *lb);
 462
 463 void snat_add_del_addr_to_fib (ip4_address_t * addr,
 464                                u8 p_len,
 465                                u32 sw_if_index,
 466                                int is_add);
 467
 468 format_function_t format_snat_user;
 469 format_function_t format_snat_static_mapping;
 470 format_function_t format_snat_static_map_to_resolve;
 471 format_function_t format_snat_session;
 472 format_function_t format_det_map_ses;
 473
 474 typedef struct {
 475   u32 cached_sw_if_index;
 476   u32 cached_ip4_address;
 477 } snat_runtime_t;
 478
 479 /** \brief Check if SNAT session is created from static mapping.
 480     @param s SNAT session
 481     @return 1 if SNAT session is created from static mapping otherwise 0
 482 */
 483 #define snat_is_session_static(s) (s->flags & SNAT_SESSION_FLAG_STATIC_MAPPING)
 484
 485 /** \brief Check if SNAT session for unknown protocol.
 486     @param s SNAT session
 487     @return 1 if SNAT session for unknown protocol otherwise 0
 488 */
 489 #define snat_is_unk_proto_session(s) (s->flags & SNAT_SESSION_FLAG_UNKNOWN_PROTO)
 490
 491 /** \brief Check if NAT session is twice NAT.
 492     @param s NAT session
 493     @return 1 if NAT session is twice NAT
 494 */
 495 #define is_twice_nat_session(s) (s->flags & SNAT_SESSION_FLAG_TWICE_NAT)
 496
 497 /** \brief Check if NAT session is load-balancing.
 498     @param s NAT session
 499     @return 1 if NAT session is load-balancing
 500 */
 501 #define is_lb_session(s) (s->flags & SNAT_SESSION_FLAG_LOAD_BALANCING)
 502
 503 /** \brief Check if NAT session is forwarding bypass.
 504     @param s NAT session
 505     @return 1 if NAT session is load-balancing
 506 */
 507 #define is_fwd_bypass_session(s) (s->flags & SNAT_SESSION_FLAG_FWD_BYPASS)
 508
 509 /** \brief Check if NAT session is endpoint dependent.
 510     @param s NAT session
 511     @return 1 if NAT session is endpoint dependent
 512 */
 513 #define is_ed_session(s) (s->flags & SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT)
 514
 515 #define nat_interface_is_inside(i) i->flags & NAT_INTERFACE_FLAG_IS_INSIDE
 516 #define nat_interface_is_outside(i) i->flags & NAT_INTERFACE_FLAG_IS_OUTSIDE
 517
 518 #define nat_log_err(...) \
 519   vlib_log(VLIB_LOG_LEVEL_ERR, snat_main.log_class, __VA_ARGS__)
 520 #define nat_log_warn(...) \
 521   vlib_log(VLIB_LOG_LEVEL_WARNING, snat_main.log_class, __VA_ARGS__)
 522 #define nat_log_notice(...) \
 523   vlib_log(VLIB_LOG_LEVEL_NOTICE, snat_main.log_class, __VA_ARGS__)
 524 #define nat_log_info(...) \
 525   vlib_log(VLIB_LOG_LEVEL_INFO, snat_main.log_class, __VA_ARGS__)
 526 #define nat_log_debug(...)\
 527   vlib_log(VLIB_LOG_LEVEL_DEBUG, snat_main.log_class, __VA_ARGS__)
 528
 529 /*
 530  * Why is this here? Because we don't need to touch this layer to
 531  * simply reply to an icmp. We need to change id to a unique
 532  * value to NAT an echo request/reply.
 533  */
 534
 535 typedef struct {
 536   u16 identifier;
 537   u16 sequence;
 538 } icmp_echo_header_t;
 539
 540 typedef struct {
 541   u16 src_port, dst_port;
 542 } tcp_udp_header_t;
 543
 544 u32 icmp_match_in2out_fast(snat_main_t *sm, vlib_node_runtime_t *node,
 545                            u32 thread_index, vlib_buffer_t *b0,
 546                            ip4_header_t *ip0, u8 *p_proto,
 547                            snat_session_key_t *p_value,
 548                            u8 *p_dont_translate, void *d, void *e);
 549 u32 icmp_match_in2out_slow(snat_main_t *sm, vlib_node_runtime_t *node,
 550                            u32 thread_index, vlib_buffer_t *b0,
 551                            ip4_header_t *ip0, u8 *p_proto,
 552                            snat_session_key_t *p_value,
 553                            u8 *p_dont_translate, void *d, void *e);
 554 u32 icmp_match_in2out_det(snat_main_t *sm, vlib_node_runtime_t *node,
 555                           u32 thread_index, vlib_buffer_t *b0,
 556                           ip4_header_t *ip0, u8 *p_proto,
 557                           snat_session_key_t *p_value,
 558                           u8 *p_dont_translate, void *d, void *e);
 559 u32 icmp_match_in2out_ed(snat_main_t *sm, vlib_node_runtime_t *node,
 560                          u32 thread_index, vlib_buffer_t *b0,
 561                          ip4_header_t *ip0, u8 *p_proto,
 562                          snat_session_key_t *p_value,
 563                          u8 *p_dont_translate, void *d, void *e);
 564 u32 icmp_match_out2in_fast(snat_main_t *sm, vlib_node_runtime_t *node,
 565                            u32 thread_index, vlib_buffer_t *b0,
 566                            ip4_header_t *ip0, u8 *p_proto,
 567                            snat_session_key_t *p_value,
 568                            u8 *p_dont_translate, void *d, void *e);
 569 u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
 570                            u32 thread_index, vlib_buffer_t *b0,
 571                            ip4_header_t *ip0, u8 *p_proto,
 572                            snat_session_key_t *p_value,
 573                            u8 *p_dont_translate, void *d, void *e);
 574 u32 icmp_match_out2in_det(snat_main_t *sm, vlib_node_runtime_t *node,
 575                           u32 thread_index, vlib_buffer_t *b0,
 576                           ip4_header_t *ip0, u8 *p_proto,
 577                           snat_session_key_t *p_value,
 578                           u8 *p_dont_translate, void *d, void *e);
 579 u32 icmp_match_out2in_ed(snat_main_t *sm, vlib_node_runtime_t *node,
 580                          u32 thread_index, vlib_buffer_t *b0,
 581                          ip4_header_t *ip0, u8 *p_proto,
 582                          snat_session_key_t *p_value,
 583                          u8 *p_dont_translate, void *d, void *e);
 584 void increment_v4_address(ip4_address_t * a);
 585 int snat_add_address(snat_main_t *sm, ip4_address_t *addr, u32 vrf_id,
 586                      u8 twice_nat);
 587 int snat_del_address(snat_main_t *sm, ip4_address_t addr, u8 delete_sm,
 588                      u8 twice_nat);
 589 void nat44_add_del_address_dpo (ip4_address_t addr, u8 is_add);
 590 int snat_add_static_mapping(ip4_address_t l_addr, ip4_address_t e_addr,
 591                             u16 l_port, u16 e_port, u32 vrf_id, int addr_only,
 592                             u32 sw_if_index, snat_protocol_t proto, int is_add,
 593                             twice_nat_type_t twice_nat, u8 out2in_only,
 594                             u8 *tag);
 595 clib_error_t * snat_api_init(vlib_main_t * vm, snat_main_t * sm);
 596 int snat_set_workers (uword * bitmap);
 597 int snat_interface_add_del(u32 sw_if_index, u8 is_inside, int is_del);
 598 int snat_interface_add_del_output_feature(u32 sw_if_index, u8 is_inside,
 599                                           int is_del);
 600 int snat_add_interface_address(snat_main_t *sm, u32 sw_if_index, int is_del,
 601                                u8 twice_nat);
 602 uword unformat_snat_protocol(unformat_input_t * input, va_list * args);
 603 u8 * format_snat_protocol(u8 * s, va_list * args);
 604 int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 605                                      snat_protocol_t proto, u32 vrf_id,
 606                                      nat44_lb_addr_port_t *locals, u8 is_add,
 607                                      twice_nat_type_t twice_nat, u8 out2in_only,
 608                                      u8 *tag);
 609 int nat44_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
 610                        snat_protocol_t proto, u32 vrf_id, int is_in);
 611 int nat44_del_ed_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
 612                           ip4_address_t *eh_addr, u16 eh_port, u8 proto,
 613                           u32 vrf_id, int is_in);
 614 void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
 615                             u32 thread_index);
 616 snat_user_t * nat_user_get_or_create (snat_main_t *sm, ip4_address_t *addr,
 617                                       u32 fib_index, u32 thread_index);
 618 snat_session_t * nat_session_alloc_or_recycle (snat_main_t *sm, snat_user_t *u,
 619                                                u32 thread_index);
 620 void nat_set_alloc_addr_and_port_mape (u16 psid, u16 psid_offset,
 621                                        u16 psid_length);
 622 void nat_set_alloc_addr_and_port_default (void);
 623
 624 #endif /* __included_snat_h__ */