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 #define SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT   16
 133 #define SNAT_SESSION_FLAG_FWD_BYPASS           32
 134
 135 #define NAT_INTERFACE_FLAG_IS_INSIDE 1
 136 #define NAT_INTERFACE_FLAG_IS_OUTSIDE 2
 137
 138 typedef CLIB_PACKED(struct {
 139   snat_session_key_t out2in;    /* 0-15 */
 140
 141   snat_session_key_t in2out;    /* 16-31 */
 142
 143   u32 flags;                    /* 32-35 */
 144
 145   /* per-user translations */
 146   u32 per_user_index;           /* 36-39 */
 147
 148   u32 per_user_list_head_index; /* 40-43 */
 149
 150   /* Last heard timer */
 151   f64 last_heard;               /* 44-51 */
 152
 153   u64 total_bytes;              /* 52-59 */
 154
 155   u32 total_pkts;               /* 60-63 */
 156
 157   /* Outside address */
 158   u32 outside_address_index;    /* 64-67 */
 159
 160   /* External host address and port */
 161   ip4_address_t ext_host_addr;  /* 68-71 */
 162   u16 ext_host_port;            /* 72-73 */
 163
 164   /* External hos address and port after translation */
 165   ip4_address_t ext_host_nat_addr; /* 74-77 */
 166   u16 ext_host_nat_port;           /* 78-79 */
 167 }) snat_session_t;
 168
 169
 170 typedef struct {
 171   ip4_address_t addr;
 172   u32 fib_index;
 173   u32 sessions_per_user_list_head_index;
 174   u32 nsessions;
 175   u32 nstaticsessions;
 176 } snat_user_t;
 177
 178 typedef struct {
 179   ip4_address_t addr;
 180   u32 fib_index;
 181 #define _(N, i, n, s) \
 182   u16 busy_##n##_ports; \
 183   u16 * busy_##n##_ports_per_thread; \
 184   uword * busy_##n##_port_bitmap;
 185   foreach_snat_protocol
 186 #undef _
 187 } snat_address_t;
 188
 189 typedef struct {
 190   u16 in_port;
 191   snat_det_out_key_t out;
 192   u8 state;
 193   u32 expire;
 194 } snat_det_session_t;
 195
 196 typedef struct {
 197   ip4_address_t in_addr;
 198   u8 in_plen;
 199   ip4_address_t out_addr;
 200   u8 out_plen;
 201   u32 sharing_ratio;
 202   u16 ports_per_host;
 203   u32 ses_num;
 204   /* vector of sessions */
 205   snat_det_session_t * sessions;
 206 } snat_det_map_t;
 207
 208 typedef struct {
 209   ip4_address_t addr;
 210   u16 port;
 211   u8 probability;
 212   u8 prefix;
 213 } nat44_lb_addr_port_t;
 214
 215 typedef enum {
 216   TWICE_NAT_DISABLED,
 217   TWICE_NAT,
 218   TWICE_NAT_SELF,
 219 } twice_nat_type_t;
 220
 221 typedef struct {
 222   ip4_address_t local_addr;
 223   ip4_address_t external_addr;
 224   u16 local_port;
 225   u16 external_port;
 226   u8 addr_only;
 227   twice_nat_type_t twice_nat;
 228   u8 out2in_only;
 229   u32 vrf_id;
 230   u32 fib_index;
 231   snat_protocol_t proto;
 232   u32 worker_index;
 233   u8 *tag;
 234   nat44_lb_addr_port_t *locals;
 235 } snat_static_mapping_t;
 236
 237 typedef struct {
 238   u32 sw_if_index;
 239   u8 flags;
 240 } snat_interface_t;
 241
 242 typedef struct {
 243   ip4_address_t l_addr;
 244   u16 l_port;
 245   u16 e_port;
 246   u32 sw_if_index;
 247   u32 vrf_id;
 248   snat_protocol_t proto;
 249   int addr_only;
 250   int twice_nat;
 251   int is_add;
 252   u8 *tag;
 253 } snat_static_map_resolve_t;
 254
 255 typedef struct {
 256   /* Main lookup tables */
 257   clib_bihash_8_8_t out2in;
 258   clib_bihash_8_8_t in2out;
 259
 260   /* Find-a-user => src address lookup */
 261   clib_bihash_8_8_t user_hash;
 262
 263   /* User pool */
 264   snat_user_t * users;
 265
 266   /* Session pool */
 267   snat_session_t * sessions;
 268
 269   /* Pool of doubly-linked list elements */
 270   dlist_elt_t * list_pool;
 271
 272   u32 snat_thread_index;
 273 } snat_main_per_thread_data_t;
 274
 275 struct snat_main_s;
 276
 277 typedef u32 snat_icmp_match_function_t (struct snat_main_s *sm,
 278                                         vlib_node_runtime_t *node,
 279                                         u32 thread_index,
 280                                         vlib_buffer_t *b0,
 281                                         ip4_header_t *ip0,
 282                                         u8 *p_proto,
 283                                         snat_session_key_t *p_value,
 284                                         u8 *p_dont_translate,
 285                                         void *d,
 286                                         void *e);
 287
 288 typedef u32 (snat_get_worker_function_t) (ip4_header_t * ip, u32 rx_fib_index);
 289
 290 typedef int nat_alloc_out_addr_and_port_function_t (snat_address_t * addresses,
 291                                                     u32 fib_index,
 292                                                     u32 thread_index,
 293                                                     snat_session_key_t * k,
 294                                                     u32 * address_indexp,
 295                                                     u16 port_per_thread,
 296                                                     u32 snat_thread_index);
 297
 298 typedef struct snat_main_s {
 299   /* Endpoint address dependent sessions lookup tables */
 300   clib_bihash_16_8_t out2in_ed;
 301   clib_bihash_16_8_t in2out_ed;
 302
 303   snat_icmp_match_function_t * icmp_match_in2out_cb;
 304   snat_icmp_match_function_t * icmp_match_out2in_cb;
 305
 306   u32 num_workers;
 307   u32 first_worker_index;
 308   u32 next_worker;
 309   u32 * workers;
 310   snat_get_worker_function_t * worker_in2out_cb;
 311   snat_get_worker_function_t * worker_out2in_cb;
 312   u16 port_per_thread;
 313   u32 num_snat_thread;
 314
 315   /* Per thread data */
 316   snat_main_per_thread_data_t * per_thread_data;
 317
 318   /* Find a static mapping by local */
 319   clib_bihash_8_8_t static_mapping_by_local;
 320
 321   /* Find a static mapping by external */
 322   clib_bihash_8_8_t static_mapping_by_external;
 323
 324   /* Static mapping pool */
 325   snat_static_mapping_t * static_mappings;
 326
 327   /* Interface pool */
 328   snat_interface_t * interfaces;
 329   snat_interface_t * output_feature_interfaces;
 330
 331   /* Vector of outside addresses */
 332   snat_address_t * addresses;
 333   nat_alloc_out_addr_and_port_function_t *alloc_addr_and_port;
 334   u8 psid_offset;
 335   u8 psid_length;
 336   u16 psid;
 337
 338   /* Vector of twice NAT addresses for extenal hosts */
 339   snat_address_t * twice_nat_addresses;
 340
 341   /* sw_if_indices whose intfc addresses should be auto-added */
 342   u32 * auto_add_sw_if_indices;
 343   u32 * auto_add_sw_if_indices_twice_nat;
 344
 345   /* vector of interface address static mappings to resolve. */
 346   snat_static_map_resolve_t *to_resolve;
 347
 348   /* Randomize port allocation order */
 349   u32 random_seed;
 350
 351   /* Worker handoff index */
 352   u32 fq_in2out_index;
 353   u32 fq_in2out_output_index;
 354   u32 fq_out2in_index;
 355
 356   /* in2out and out2in node index */
 357   u32 in2out_node_index;
 358   u32 in2out_output_node_index;
 359   u32 out2in_node_index;
 360
 361   /* Deterministic NAT */
 362   snat_det_map_t * det_maps;
 363
 364   /* If forwarding is enabled */
 365   u8 forwarding_enabled;
 366
 367   /* Config parameters */
 368   u8 static_mapping_only;
 369   u8 static_mapping_connection_tracking;
 370   u8 deterministic;
 371   u8 out2in_dpo;
 372   u32 translation_buckets;
 373   u32 translation_memory_size;
 374   u32 max_translations;
 375   u32 user_buckets;
 376   u32 user_memory_size;
 377   u32 max_translations_per_user;
 378   u32 outside_vrf_id;
 379   u32 outside_fib_index;
 380   u32 inside_vrf_id;
 381   u32 inside_fib_index;
 382
 383   /* values of various timeouts */
 384   u32 udp_timeout;
 385   u32 tcp_established_timeout;
 386   u32 tcp_transitory_timeout;
 387   u32 icmp_timeout;
 388
 389   /* API message ID base */
 390   u16 msg_id_base;
 391
 392   /* convenience */
 393   vlib_main_t * vlib_main;
 394   vnet_main_t * vnet_main;
 395   ip4_main_t * ip4_main;
 396   ip_lookup_main_t * ip4_lookup_main;
 397   api_main_t * api_main;
 398 } snat_main_t;
 399
 400 extern snat_main_t snat_main;
 401 extern vlib_node_registration_t snat_in2out_node;
 402 extern vlib_node_registration_t snat_in2out_output_node;
 403 extern vlib_node_registration_t snat_out2in_node;
 404 extern vlib_node_registration_t snat_in2out_fast_node;
 405 extern vlib_node_registration_t snat_out2in_fast_node;
 406 extern vlib_node_registration_t snat_in2out_worker_handoff_node;
 407 extern vlib_node_registration_t snat_in2out_output_worker_handoff_node;
 408 extern vlib_node_registration_t snat_out2in_worker_handoff_node;
 409 extern vlib_node_registration_t snat_det_in2out_node;
 410 extern vlib_node_registration_t snat_det_out2in_node;
 411 extern vlib_node_registration_t snat_hairpin_dst_node;
 412 extern vlib_node_registration_t snat_hairpin_src_node;
 413
 414 void snat_free_outside_address_and_port (snat_address_t * addresses,
 415                                          u32 thread_index,
 416                                          snat_session_key_t * k,
 417                                          u32 address_index);
 418
 419 int snat_alloc_outside_address_and_port (snat_address_t * addresses,
 420                                          u32 fib_index,
 421                                          u32 thread_index,
 422                                          snat_session_key_t * k,
 423                                          u32 * address_indexp,
 424                                          u16 port_per_thread,
 425                                          u32 snat_thread_index);
 426
 427 int snat_static_mapping_match (snat_main_t * sm,
 428                                snat_session_key_t match,
 429                                snat_session_key_t * mapping,
 430                                u8 by_external,
 431                                u8 *is_addr_only,
 432                                twice_nat_type_t *twice_nat,
 433                                u8 *lb);
 434
 435 void snat_add_del_addr_to_fib (ip4_address_t * addr,
 436                                u8 p_len,
 437                                u32 sw_if_index,
 438                                int is_add);
 439
 440 format_function_t format_snat_user;
 441 format_function_t format_snat_static_mapping;
 442 format_function_t format_snat_static_map_to_resolve;
 443 format_function_t format_det_map_ses;
 444
 445 typedef struct {
 446   u32 cached_sw_if_index;
 447   u32 cached_ip4_address;
 448 } snat_runtime_t;
 449
 450 /** \brief Check if SNAT session is created from static mapping.
 451     @param s SNAT session
 452     @return 1 if SNAT session is created from static mapping otherwise 0
 453 */
 454 #define snat_is_session_static(s) (s->flags & SNAT_SESSION_FLAG_STATIC_MAPPING)
 455
 456 /** \brief Check if SNAT session for unknown protocol.
 457     @param s SNAT session
 458     @return 1 if SNAT session for unknown protocol otherwise 0
 459 */
 460 #define snat_is_unk_proto_session(s) (s->flags & SNAT_SESSION_FLAG_UNKNOWN_PROTO)
 461
 462 /** \brief Check if NAT session is twice NAT.
 463     @param s NAT session
 464     @return 1 if NAT session is twice NAT
 465 */
 466 #define is_twice_nat_session(s) (s->flags & SNAT_SESSION_FLAG_TWICE_NAT)
 467
 468 /** \brief Check if NAT session is load-balancing.
 469     @param s NAT session
 470     @return 1 if NAT session is load-balancing
 471 */
 472 #define is_lb_session(s) (s->flags & SNAT_SESSION_FLAG_LOAD_BALANCING)
 473
 474 /** \brief Check if NAT session is forwarding bypass.
 475     @param s NAT session
 476     @return 1 if NAT session is load-balancing
 477 */
 478 #define is_fwd_bypass_session(s) (s->flags & SNAT_SESSION_FLAG_FWD_BYPASS)
 479
 480 /** \brief Check if NAT session is endpoint dependent.
 481     @param s NAT session
 482     @return 1 if NAT session is endpoint dependent
 483 */
 484 #define is_ed_session(s) (s->flags & SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT)
 485
 486 #define nat_interface_is_inside(i) i->flags & NAT_INTERFACE_FLAG_IS_INSIDE
 487 #define nat_interface_is_outside(i) i->flags & NAT_INTERFACE_FLAG_IS_OUTSIDE
 488
 489 /*
 490  * Why is this here? Because we don't need to touch this layer to
 491  * simply reply to an icmp. We need to change id to a unique
 492  * value to NAT an echo request/reply.
 493  */
 494
 495 typedef struct {
 496   u16 identifier;
 497   u16 sequence;
 498 } icmp_echo_header_t;
 499
 500 always_inline u32
 501 ip_proto_to_snat_proto (u8 ip_proto)
 502 {
 503   u32 snat_proto = ~0;
 504
 505   snat_proto = (ip_proto == IP_PROTOCOL_UDP) ? SNAT_PROTOCOL_UDP : snat_proto;
 506   snat_proto = (ip_proto == IP_PROTOCOL_TCP) ? SNAT_PROTOCOL_TCP : snat_proto;
 507   snat_proto = (ip_proto == IP_PROTOCOL_ICMP) ? SNAT_PROTOCOL_ICMP : snat_proto;
 508   snat_proto = (ip_proto == IP_PROTOCOL_ICMP6) ? SNAT_PROTOCOL_ICMP : snat_proto;
 509
 510   return snat_proto;
 511 }
 512
 513 always_inline u8
 514 snat_proto_to_ip_proto (snat_protocol_t snat_proto)
 515 {
 516   u8 ip_proto = ~0;
 517
 518   ip_proto = (snat_proto == SNAT_PROTOCOL_UDP) ? IP_PROTOCOL_UDP : ip_proto;
 519   ip_proto = (snat_proto == SNAT_PROTOCOL_TCP) ? IP_PROTOCOL_TCP : ip_proto;
 520   ip_proto = (snat_proto == SNAT_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP : ip_proto;
 521
 522   return ip_proto;
 523 }
 524
 525 typedef struct {
 526   u16 src_port, dst_port;
 527 } tcp_udp_header_t;
 528
 529 u32 icmp_match_in2out_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_in2out_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_in2out_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 u32 icmp_match_out2in_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_out2in_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_out2in_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 void increment_v4_address(ip4_address_t * a);
 560 void snat_add_address(snat_main_t *sm, ip4_address_t *addr, u32 vrf_id,
 561                       u8 twice_nat);
 562 int snat_del_address(snat_main_t *sm, ip4_address_t addr, u8 delete_sm,
 563                      u8 twice_nat);
 564 void nat44_add_del_address_dpo (ip4_address_t addr, u8 is_add);
 565 int snat_add_static_mapping(ip4_address_t l_addr, ip4_address_t e_addr,
 566                             u16 l_port, u16 e_port, u32 vrf_id, int addr_only,
 567                             u32 sw_if_index, snat_protocol_t proto, int is_add,
 568                             twice_nat_type_t twice_nat, u8 out2in_only,
 569                             u8 *tag);
 570 clib_error_t * snat_api_init(vlib_main_t * vm, snat_main_t * sm);
 571 int snat_set_workers (uword * bitmap);
 572 int snat_interface_add_del(u32 sw_if_index, u8 is_inside, int is_del);
 573 int snat_interface_add_del_output_feature(u32 sw_if_index, u8 is_inside,
 574                                           int is_del);
 575 int snat_add_interface_address(snat_main_t *sm, u32 sw_if_index, int is_del,
 576                                u8 twice_nat);
 577 uword unformat_snat_protocol(unformat_input_t * input, va_list * args);
 578 u8 * format_snat_protocol(u8 * s, va_list * args);
 579 int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 580                                      snat_protocol_t proto, u32 vrf_id,
 581                                      nat44_lb_addr_port_t *locals, u8 is_add,
 582                                      twice_nat_type_t twice_nat, u8 out2in_only,
 583                                      u8 *tag);
 584 int nat44_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
 585                        snat_protocol_t proto, u32 vrf_id, int is_in);
 586 void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
 587                             u32 thread_index);
 588 snat_user_t * nat_user_get_or_create (snat_main_t *sm, ip4_address_t *addr,
 589                                       u32 fib_index, u32 thread_index);
 590 snat_session_t * nat_session_alloc_or_recycle (snat_main_t *sm, snat_user_t *u,
 591                                                u32 thread_index);
 592 void nat_set_alloc_addr_and_port_mape (u16 psid, u16 psid_offset,
 593                                        u16 psid_length);
 594 void nat_set_alloc_addr_and_port_default (void);
 595
 596 static_always_inline u8
 597 icmp_is_error_message (icmp46_header_t * icmp)
 598 {
 599   switch(icmp->type)
 600     {
 601     case ICMP4_destination_unreachable:
 602     case ICMP4_time_exceeded:
 603     case ICMP4_parameter_problem:
 604     case ICMP4_source_quench:
 605     case ICMP4_redirect:
 606     case ICMP4_alternate_host_address:
 607       return 1;
 608     }
 609   return 0;
 610 }
 611
 612 static_always_inline u8
 613 is_interface_addr(snat_main_t *sm, vlib_node_runtime_t *node, u32 sw_if_index0,
 614                   u32 ip4_addr)
 615 {
 616   snat_runtime_t *rt = (snat_runtime_t *) node->runtime_data;
 617   ip4_address_t * first_int_addr;
 618
 619   if (PREDICT_FALSE(rt->cached_sw_if_index != sw_if_index0))
 620     {
 621       first_int_addr =
 622         ip4_interface_first_address (sm->ip4_main, sw_if_index0,
 623                                      0 /* just want the address */);
 624       rt->cached_sw_if_index = sw_if_index0;
 625       if (first_int_addr)
 626         rt->cached_ip4_address = first_int_addr->as_u32;
 627       else
 628         rt->cached_ip4_address = 0;
 629     }
 630
 631   if (PREDICT_FALSE(ip4_addr == rt->cached_ip4_address))
 632     return 1;
 633   else
 634     return 0;
 635 }
 636
 637 always_inline u8
 638 maximum_sessions_exceeded (snat_main_t *sm, u32 thread_index)
 639 {
 640   if (pool_elts (sm->per_thread_data[thread_index].sessions) >= sm->max_translations)
 641     return 1;
 642
 643   return 0;
 644 }
 645
 646 static_always_inline void
 647 nat_send_all_to_node(vlib_main_t *vm, u32 *bi_vector,
 648                      vlib_node_runtime_t *node, vlib_error_t *error, u32 next)
 649 {
 650   u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
 651
 652   from = bi_vector;
 653   n_left_from = vec_len(bi_vector);
 654   next_index = node->cached_next_index;
 655   while (n_left_from > 0) {
 656     vlib_get_next_frame(vm, node, next_index, to_next, n_left_to_next);
 657     while (n_left_from > 0 && n_left_to_next > 0) {
 658       u32 bi0 = to_next[0] = from[0];
 659       from += 1;
 660       n_left_from -= 1;
 661       to_next += 1;
 662       n_left_to_next -= 1;
 663       vlib_buffer_t *p0 = vlib_get_buffer(vm, bi0);
 664       p0->error = *error;
 665       vlib_validate_buffer_enqueue_x1(vm, node, next_index, to_next,
 666                                       n_left_to_next, bi0, next);
 667     }
 668     vlib_put_next_frame(vm, node, next_index, n_left_to_next);
 669   }
 670 }
 671
 672 always_inline void
 673 user_session_increment(snat_main_t *sm, snat_user_t *u, u8 is_static)
 674 {
 675   if (u->nsessions + u->nstaticsessions < sm->max_translations_per_user)
 676     {
 677       if (is_static)
 678         u->nstaticsessions++;
 679       else
 680         u->nsessions++;
 681     }
 682 }
 683
 684 #endif /* __included_snat_h__ */