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
  32
  33 #define SNAT_UDP_TIMEOUT 300
  34 #define SNAT_UDP_TIMEOUT_MIN 120
  35 #define SNAT_TCP_TRANSITORY_TIMEOUT 240
  36 #define SNAT_TCP_ESTABLISHED_TIMEOUT 7440
  37 #define SNAT_TCP_INCOMING_SYN 6
  38 #define SNAT_ICMP_TIMEOUT 60
  39
  40 #define SNAT_FLAG_HAIRPINNING (1 << 0)
  41
  42 /* Key */
  43 typedef struct {
  44   union
  45   {
  46     struct
  47     {
  48       ip4_address_t addr;
  49       u16 port;
  50       u16 protocol:3,
  51         fib_index:13;
  52     };
  53     u64 as_u64;
  54   };
  55 } snat_session_key_t;
  56
  57 typedef struct {
  58   union
  59   {
  60     struct
  61     {
  62       ip4_address_t l_addr;
  63       ip4_address_t r_addr;
  64       u32 proto:8,
  65           fib_index:24;
  66       u16 l_port;
  67       u16 r_port;
  68     };
  69     u64 as_u64[2];
  70   };
  71 } nat_ed_ses_key_t;
  72
  73 typedef struct {
  74   union
  75   {
  76     struct
  77     {
  78       ip4_address_t ext_host_addr;
  79       u16 ext_host_port;
  80       u16 out_port;
  81     };
  82     u64 as_u64;
  83   };
  84 } snat_det_out_key_t;
  85
  86 typedef struct {
  87   union
  88   {
  89     struct
  90     {
  91       ip4_address_t addr;
  92       u32 fib_index;
  93     };
  94     u64 as_u64;
  95   };
  96 } snat_user_key_t;
  97
  98
  99 #define foreach_snat_protocol \
 100   _(UDP, 0, udp, "udp")       \
 101   _(TCP, 1, tcp, "tcp")       \
 102   _(ICMP, 2, icmp, "icmp")
 103
 104 typedef enum {
 105 #define _(N, i, n, s) SNAT_PROTOCOL_##N = i,
 106   foreach_snat_protocol
 107 #undef _
 108 } snat_protocol_t;
 109
 110
 111 #define foreach_snat_session_state          \
 112   _(0, UNKNOWN, "unknown")                 \
 113   _(1, UDP_ACTIVE, "udp-active")           \
 114   _(2, TCP_SYN_SENT, "tcp-syn-sent")       \
 115   _(3, TCP_ESTABLISHED, "tcp-established") \
 116   _(4, TCP_FIN_WAIT, "tcp-fin-wait")       \
 117   _(5, TCP_CLOSE_WAIT, "tcp-close-wait")   \
 118   _(6, TCP_LAST_ACK, "tcp-last-ack")       \
 119   _(7, ICMP_ACTIVE, "icmp-active")
 120
 121 typedef enum {
 122 #define _(v, N, s) SNAT_SESSION_##N = v,
 123   foreach_snat_session_state
 124 #undef _
 125 } snat_session_state_t;
 126
 127
 128 #define SNAT_SESSION_FLAG_STATIC_MAPPING 1
 129 #define SNAT_SESSION_FLAG_UNKNOWN_PROTO  2
 130 #define SNAT_SESSION_FLAG_LOAD_BALANCING 4
 131 #define SNAT_SESSION_FLAG_TWICE_NAT      8
 132
 133 #define NAT_INTERFACE_FLAG_IS_INSIDE 1
 134 #define NAT_INTERFACE_FLAG_IS_OUTSIDE 2
 135
 136 typedef CLIB_PACKED(struct {
 137   snat_session_key_t out2in;    /* 0-15 */
 138
 139   snat_session_key_t in2out;    /* 16-31 */
 140
 141   u32 flags;                    /* 32-35 */
 142
 143   /* per-user translations */
 144   u32 per_user_index;           /* 36-39 */
 145
 146   u32 per_user_list_head_index; /* 40-43 */
 147
 148   /* Last heard timer */
 149   f64 last_heard;               /* 44-51 */
 150
 151   u64 total_bytes;              /* 52-59 */
 152
 153   u32 total_pkts;               /* 60-63 */
 154
 155   /* Outside address */
 156   u32 outside_address_index;    /* 64-67 */
 157
 158   /* External host address and port */
 159   ip4_address_t ext_host_addr;  /* 68-71 */
 160   u16 ext_host_port;            /* 72-73 */
 161
 162   /* External hos address and port after translation */
 163   ip4_address_t ext_host_nat_addr; /* 74-77 */
 164   u16 ext_host_nat_port;           /* 78-79 */
 165 }) snat_session_t;
 166
 167
 168 typedef struct {
 169   ip4_address_t addr;
 170   u32 fib_index;
 171   u32 sessions_per_user_list_head_index;
 172   u32 nsessions;
 173   u32 nstaticsessions;
 174 } snat_user_t;
 175
 176 typedef struct {
 177   ip4_address_t addr;
 178   u32 fib_index;
 179 #define _(N, i, n, s) \
 180   u16 busy_##n##_ports; \
 181   u16 * busy_##n##_ports_per_thread; \
 182   uword * busy_##n##_port_bitmap;
 183   foreach_snat_protocol
 184 #undef _
 185 } snat_address_t;
 186
 187 typedef struct {
 188   u16 in_port;
 189   snat_det_out_key_t out;
 190   u8 state;
 191   u32 expire;
 192 } snat_det_session_t;
 193
 194 typedef struct {
 195   ip4_address_t in_addr;
 196   u8 in_plen;
 197   ip4_address_t out_addr;
 198   u8 out_plen;
 199   u32 sharing_ratio;
 200   u16 ports_per_host;
 201   u32 ses_num;
 202   /* vector of sessions */
 203   snat_det_session_t * sessions;
 204 } snat_det_map_t;
 205
 206 typedef struct {
 207   ip4_address_t addr;
 208   u16 port;
 209   u8 probability;
 210   u8 prefix;
 211 } nat44_lb_addr_port_t;
 212
 213 typedef struct {
 214   ip4_address_t local_addr;
 215   ip4_address_t external_addr;
 216   u16 local_port;
 217   u16 external_port;
 218   u8 addr_only;
 219   u8 twice_nat;
 220   u8 out2in_only;
 221   u32 vrf_id;
 222   u32 fib_index;
 223   snat_protocol_t proto;
 224   u32 worker_index;
 225   u8 *tag;
 226   nat44_lb_addr_port_t *locals;
 227 } snat_static_mapping_t;
 228
 229 typedef struct {
 230   u32 sw_if_index;
 231   u8 flags;
 232 } snat_interface_t;
 233
 234 typedef struct {
 235   ip4_address_t l_addr;
 236   u16 l_port;
 237   u16 e_port;
 238   u32 sw_if_index;
 239   u32 vrf_id;
 240   snat_protocol_t proto;
 241   int addr_only;
 242   int twice_nat;
 243   int is_add;
 244   u8 *tag;
 245 } snat_static_map_resolve_t;
 246
 247 typedef struct {
 248   /* Main lookup tables */
 249   clib_bihash_8_8_t out2in;
 250   clib_bihash_8_8_t in2out;
 251
 252   /* Find-a-user => src address lookup */
 253   clib_bihash_8_8_t user_hash;
 254
 255   /* User pool */
 256   snat_user_t * users;
 257
 258   /* Session pool */
 259   snat_session_t * sessions;
 260
 261   /* Pool of doubly-linked list elements */
 262   dlist_elt_t * list_pool;
 263
 264   u32 snat_thread_index;
 265 } snat_main_per_thread_data_t;
 266
 267 struct snat_main_s;
 268
 269 typedef u32 snat_icmp_match_function_t (struct snat_main_s *sm,
 270                                         vlib_node_runtime_t *node,
 271                                         u32 thread_index,
 272                                         vlib_buffer_t *b0,
 273                                         ip4_header_t *ip0,
 274                                         u8 *p_proto,
 275                                         snat_session_key_t *p_value,
 276                                         u8 *p_dont_translate,
 277                                         void *d,
 278                                         void *e);
 279
 280 typedef u32 (snat_get_worker_function_t) (ip4_header_t * ip, u32 rx_fib_index);
 281
 282 typedef int nat_alloc_out_addr_and_port_function_t (snat_address_t * addresses,
 283                                                     u32 fib_index,
 284                                                     u32 thread_index,
 285                                                     snat_session_key_t * k,
 286                                                     u32 * address_indexp,
 287                                                     u16 port_per_thread,
 288                                                     u32 snat_thread_index);
 289
 290 typedef struct snat_main_s {
 291   /* Endpoint address dependent sessions lookup tables */
 292   clib_bihash_16_8_t out2in_ed;
 293   clib_bihash_16_8_t in2out_ed;
 294
 295   snat_icmp_match_function_t * icmp_match_in2out_cb;
 296   snat_icmp_match_function_t * icmp_match_out2in_cb;
 297
 298   u32 num_workers;
 299   u32 first_worker_index;
 300   u32 next_worker;
 301   u32 * workers;
 302   snat_get_worker_function_t * worker_in2out_cb;
 303   snat_get_worker_function_t * worker_out2in_cb;
 304   u16 port_per_thread;
 305   u32 num_snat_thread;
 306
 307   /* Per thread data */
 308   snat_main_per_thread_data_t * per_thread_data;
 309
 310   /* Find a static mapping by local */
 311   clib_bihash_8_8_t static_mapping_by_local;
 312
 313   /* Find a static mapping by external */
 314   clib_bihash_8_8_t static_mapping_by_external;
 315
 316   /* Static mapping pool */
 317   snat_static_mapping_t * static_mappings;
 318
 319   /* Interface pool */
 320   snat_interface_t * interfaces;
 321   snat_interface_t * output_feature_interfaces;
 322
 323   /* Vector of outside addresses */
 324   snat_address_t * addresses;
 325   nat_alloc_out_addr_and_port_function_t *alloc_addr_and_port;
 326   u8 psid_offset;
 327   u8 psid_length;
 328   u16 psid;
 329
 330   /* Vector of twice NAT addresses for extenal hosts */
 331   snat_address_t * twice_nat_addresses;
 332
 333   /* sw_if_indices whose intfc addresses should be auto-added */
 334   u32 * auto_add_sw_if_indices;
 335   u32 * auto_add_sw_if_indices_twice_nat;
 336
 337   /* vector of interface address static mappings to resolve. */
 338   snat_static_map_resolve_t *to_resolve;
 339
 340   /* Randomize port allocation order */
 341   u32 random_seed;
 342
 343   /* Worker handoff index */
 344   u32 fq_in2out_index;
 345   u32 fq_in2out_output_index;
 346   u32 fq_out2in_index;
 347
 348   /* in2out and out2in node index */
 349   u32 in2out_node_index;
 350   u32 in2out_output_node_index;
 351   u32 out2in_node_index;
 352
 353   /* Deterministic NAT */
 354   snat_det_map_t * det_maps;
 355
 356   /* If forwarding is enabled */
 357   u8 forwarding_enabled;
 358
 359   /* Config parameters */
 360   u8 static_mapping_only;
 361   u8 static_mapping_connection_tracking;
 362   u8 deterministic;
 363   u8 out2in_dpo;
 364   u32 translation_buckets;
 365   u32 translation_memory_size;
 366   u32 max_translations;
 367   u32 user_buckets;
 368   u32 user_memory_size;
 369   u32 max_translations_per_user;
 370   u32 outside_vrf_id;
 371   u32 outside_fib_index;
 372   u32 inside_vrf_id;
 373   u32 inside_fib_index;
 374
 375   /* values of various timeouts */
 376   u32 udp_timeout;
 377   u32 tcp_established_timeout;
 378   u32 tcp_transitory_timeout;
 379   u32 icmp_timeout;
 380
 381   /* API message ID base */
 382   u16 msg_id_base;
 383
 384   /* convenience */
 385   vlib_main_t * vlib_main;
 386   vnet_main_t * vnet_main;
 387   ip4_main_t * ip4_main;
 388   ip_lookup_main_t * ip4_lookup_main;
 389   api_main_t * api_main;
 390 } snat_main_t;
 391
 392 extern snat_main_t snat_main;
 393 extern vlib_node_registration_t snat_in2out_node;
 394 extern vlib_node_registration_t snat_in2out_output_node;
 395 extern vlib_node_registration_t snat_out2in_node;
 396 extern vlib_node_registration_t snat_in2out_fast_node;
 397 extern vlib_node_registration_t snat_out2in_fast_node;
 398 extern vlib_node_registration_t snat_in2out_worker_handoff_node;
 399 extern vlib_node_registration_t snat_in2out_output_worker_handoff_node;
 400 extern vlib_node_registration_t snat_out2in_worker_handoff_node;
 401 extern vlib_node_registration_t snat_det_in2out_node;
 402 extern vlib_node_registration_t snat_det_out2in_node;
 403 extern vlib_node_registration_t snat_hairpin_dst_node;
 404 extern vlib_node_registration_t snat_hairpin_src_node;
 405
 406 void snat_free_outside_address_and_port (snat_address_t * addresses,
 407                                          u32 thread_index,
 408                                          snat_session_key_t * k,
 409                                          u32 address_index);
 410
 411 int snat_alloc_outside_address_and_port (snat_address_t * addresses,
 412                                          u32 fib_index,
 413                                          u32 thread_index,
 414                                          snat_session_key_t * k,
 415                                          u32 * address_indexp,
 416                                          u16 port_per_thread,
 417                                          u32 snat_thread_index);
 418
 419 int snat_static_mapping_match (snat_main_t * sm,
 420                                snat_session_key_t match,
 421                                snat_session_key_t * mapping,
 422                                u8 by_external,
 423                                u8 *is_addr_only,
 424                                u8 *twice_nat);
 425
 426 void snat_add_del_addr_to_fib (ip4_address_t * addr,
 427                                u8 p_len,
 428                                u32 sw_if_index,
 429                                int is_add);
 430
 431 format_function_t format_snat_user;
 432 format_function_t format_snat_static_mapping;
 433 format_function_t format_snat_static_map_to_resolve;
 434 format_function_t format_det_map_ses;
 435
 436 typedef struct {
 437   u32 cached_sw_if_index;
 438   u32 cached_ip4_address;
 439 } snat_runtime_t;
 440
 441 /** \brief Check if SNAT session is created from static mapping.
 442     @param s SNAT session
 443     @return 1 if SNAT session is created from static mapping otherwise 0
 444 */
 445 #define snat_is_session_static(s) (s->flags & SNAT_SESSION_FLAG_STATIC_MAPPING)
 446
 447 /** \brief Check if SNAT session for unknown protocol.
 448     @param s SNAT session
 449     @return 1 if SNAT session for unknown protocol otherwise 0
 450 */
 451 #define snat_is_unk_proto_session(s) (s->flags & SNAT_SESSION_FLAG_UNKNOWN_PROTO)
 452
 453 /** \brief Check if NAT session is twice NAT.
 454     @param s NAT session
 455     @return 1 if NAT session is twice NAT
 456 */
 457 #define is_twice_nat_session(s) (s->flags & SNAT_SESSION_FLAG_TWICE_NAT)
 458
 459 /** \brief Check if NAT session is load-balancing.
 460     @param s NAT session
 461     @return 1 if NAT session is load-balancing
 462 */
 463 #define is_lb_session(s) (s->flags & SNAT_SESSION_FLAG_LOAD_BALANCING)
 464
 465 /** \brief Check if NAT session is endpoint dependent.
 466     @param s NAT session
 467     @return 1 if NAT session is endpoint dependent
 468 */
 469 #define is_ed_session(s) (snat_is_unk_proto_session (s) || is_twice_nat_session (s) || is_lb_session (s))
 470
 471 #define nat_interface_is_inside(i) i->flags & NAT_INTERFACE_FLAG_IS_INSIDE
 472 #define nat_interface_is_outside(i) i->flags & NAT_INTERFACE_FLAG_IS_OUTSIDE
 473
 474 /*
 475  * Why is this here? Because we don't need to touch this layer to
 476  * simply reply to an icmp. We need to change id to a unique
 477  * value to NAT an echo request/reply.
 478  */
 479
 480 typedef struct {
 481   u16 identifier;
 482   u16 sequence;
 483 } icmp_echo_header_t;
 484
 485 always_inline u32
 486 ip_proto_to_snat_proto (u8 ip_proto)
 487 {
 488   u32 snat_proto = ~0;
 489
 490   snat_proto = (ip_proto == IP_PROTOCOL_UDP) ? SNAT_PROTOCOL_UDP : snat_proto;
 491   snat_proto = (ip_proto == IP_PROTOCOL_TCP) ? SNAT_PROTOCOL_TCP : snat_proto;
 492   snat_proto = (ip_proto == IP_PROTOCOL_ICMP) ? SNAT_PROTOCOL_ICMP : snat_proto;
 493   snat_proto = (ip_proto == IP_PROTOCOL_ICMP6) ? SNAT_PROTOCOL_ICMP : snat_proto;
 494
 495   return snat_proto;
 496 }
 497
 498 always_inline u8
 499 snat_proto_to_ip_proto (snat_protocol_t snat_proto)
 500 {
 501   u8 ip_proto = ~0;
 502
 503   ip_proto = (snat_proto == SNAT_PROTOCOL_UDP) ? IP_PROTOCOL_UDP : ip_proto;
 504   ip_proto = (snat_proto == SNAT_PROTOCOL_TCP) ? IP_PROTOCOL_TCP : ip_proto;
 505   ip_proto = (snat_proto == SNAT_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP : ip_proto;
 506
 507   return ip_proto;
 508 }
 509
 510 typedef struct {
 511   u16 src_port, dst_port;
 512 } tcp_udp_header_t;
 513
 514 u32 icmp_match_in2out_fast(snat_main_t *sm, vlib_node_runtime_t *node,
 515                            u32 thread_index, vlib_buffer_t *b0,
 516                            ip4_header_t *ip0, u8 *p_proto,
 517                            snat_session_key_t *p_value,
 518                            u8 *p_dont_translate, void *d, void *e);
 519 u32 icmp_match_in2out_slow(snat_main_t *sm, vlib_node_runtime_t *node,
 520                            u32 thread_index, vlib_buffer_t *b0,
 521                            ip4_header_t *ip0, u8 *p_proto,
 522                            snat_session_key_t *p_value,
 523                            u8 *p_dont_translate, void *d, void *e);
 524 u32 icmp_match_in2out_det(snat_main_t *sm, vlib_node_runtime_t *node,
 525                           u32 thread_index, vlib_buffer_t *b0,
 526                           ip4_header_t *ip0, u8 *p_proto,
 527                           snat_session_key_t *p_value,
 528                           u8 *p_dont_translate, void *d, void *e);
 529 u32 icmp_match_out2in_fast(snat_main_t *sm, vlib_node_runtime_t *node,
 530                            u32 thread_index, vlib_buffer_t *b0,
 531                            ip4_header_t *ip0, u8 *p_proto,
 532                            snat_session_key_t *p_value,
 533                            u8 *p_dont_translate, void *d, void *e);
 534 u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
 535                            u32 thread_index, vlib_buffer_t *b0,
 536                            ip4_header_t *ip0, u8 *p_proto,
 537                            snat_session_key_t *p_value,
 538                            u8 *p_dont_translate, void *d, void *e);
 539 u32 icmp_match_out2in_det(snat_main_t *sm, vlib_node_runtime_t *node,
 540                           u32 thread_index, vlib_buffer_t *b0,
 541                           ip4_header_t *ip0, u8 *p_proto,
 542                           snat_session_key_t *p_value,
 543                           u8 *p_dont_translate, void *d, void *e);
 544 void increment_v4_address(ip4_address_t * a);
 545 void snat_add_address(snat_main_t *sm, ip4_address_t *addr, u32 vrf_id,
 546                       u8 twice_nat);
 547 int snat_del_address(snat_main_t *sm, ip4_address_t addr, u8 delete_sm,
 548                      u8 twice_nat);
 549 void nat44_add_del_address_dpo (ip4_address_t addr, u8 is_add);
 550 int snat_add_static_mapping(ip4_address_t l_addr, ip4_address_t e_addr,
 551                             u16 l_port, u16 e_port, u32 vrf_id, int addr_only,
 552                             u32 sw_if_index, snat_protocol_t proto, int is_add,
 553                             u8 twice_nat, u8 out2in_only, u8 *tag);
 554 clib_error_t * snat_api_init(vlib_main_t * vm, snat_main_t * sm);
 555 int snat_set_workers (uword * bitmap);
 556 int snat_interface_add_del(u32 sw_if_index, u8 is_inside, int is_del);
 557 int snat_interface_add_del_output_feature(u32 sw_if_index, u8 is_inside,
 558                                           int is_del);
 559 int snat_add_interface_address(snat_main_t *sm, u32 sw_if_index, int is_del,
 560                                u8 twice_nat);
 561 uword unformat_snat_protocol(unformat_input_t * input, va_list * args);
 562 u8 * format_snat_protocol(u8 * s, va_list * args);
 563 int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 564                                      snat_protocol_t proto, u32 vrf_id,
 565                                      nat44_lb_addr_port_t *locals, u8 is_add,
 566                                      u8 twice_nat, u8 out2in_only, u8 *tag);
 567 int nat44_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
 568                        snat_protocol_t proto, u32 vrf_id, int is_in);
 569 void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
 570                             u32 thread_index);
 571 snat_user_t * nat_user_get_or_create (snat_main_t *sm, ip4_address_t *addr,
 572                                       u32 fib_index, u32 thread_index);
 573 snat_session_t * nat_session_alloc_or_recycle (snat_main_t *sm, snat_user_t *u,
 574                                                u32 thread_index);
 575 void nat_set_alloc_addr_and_port_mape (u16 psid, u16 psid_offset,
 576                                        u16 psid_length);
 577 void nat_set_alloc_addr_and_port_default (void);
 578
 579 static_always_inline u8
 580 icmp_is_error_message (icmp46_header_t * icmp)
 581 {
 582   switch(icmp->type)
 583     {
 584     case ICMP4_destination_unreachable:
 585     case ICMP4_time_exceeded:
 586     case ICMP4_parameter_problem:
 587     case ICMP4_source_quench:
 588     case ICMP4_redirect:
 589     case ICMP4_alternate_host_address:
 590       return 1;
 591     }
 592   return 0;
 593 }
 594
 595 static_always_inline u8
 596 is_interface_addr(snat_main_t *sm, vlib_node_runtime_t *node, u32 sw_if_index0,
 597                   u32 ip4_addr)
 598 {
 599   snat_runtime_t *rt = (snat_runtime_t *) node->runtime_data;
 600   ip4_address_t * first_int_addr;
 601
 602   if (PREDICT_FALSE(rt->cached_sw_if_index != sw_if_index0))
 603     {
 604       first_int_addr =
 605         ip4_interface_first_address (sm->ip4_main, sw_if_index0,
 606                                      0 /* just want the address */);
 607       rt->cached_sw_if_index = sw_if_index0;
 608       if (first_int_addr)
 609         rt->cached_ip4_address = first_int_addr->as_u32;
 610       else
 611         rt->cached_ip4_address = 0;
 612     }
 613
 614   if (PREDICT_FALSE(ip4_addr == rt->cached_ip4_address))
 615     return 1;
 616   else
 617     return 0;
 618 }
 619
 620 always_inline u8
 621 maximum_sessions_exceeded (snat_main_t *sm, u32 thread_index)
 622 {
 623   if (pool_elts (sm->per_thread_data[thread_index].sessions) >= sm->max_translations)
 624     return 1;
 625
 626   return 0;
 627 }
 628
 629 static_always_inline void
 630 nat_send_all_to_node(vlib_main_t *vm, u32 *bi_vector,
 631                      vlib_node_runtime_t *node, vlib_error_t *error, u32 next)
 632 {
 633   u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
 634
 635   from = bi_vector;
 636   n_left_from = vec_len(bi_vector);
 637   next_index = node->cached_next_index;
 638   while (n_left_from > 0) {
 639     vlib_get_next_frame(vm, node, next_index, to_next, n_left_to_next);
 640     while (n_left_from > 0 && n_left_to_next > 0) {
 641       u32 bi0 = to_next[0] = from[0];
 642       from += 1;
 643       n_left_from -= 1;
 644       to_next += 1;
 645       n_left_to_next -= 1;
 646       vlib_buffer_t *p0 = vlib_get_buffer(vm, bi0);
 647       p0->error = *error;
 648       vlib_validate_buffer_enqueue_x1(vm, node, next_index, to_next,
 649                                       n_left_to_next, bi0, next);
 650     }
 651     vlib_put_next_frame(vm, node, next_index, n_left_to_next);
 652   }
 653 }
 654
 655 #endif /* __included_snat_h__ */