src/plugins/snat/snat.h

   1
   2 /*
   3  * snat.h - simple nat 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_snat_h__
  19 #define __included_snat_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/dlist.h>
  28 #include <vppinfra/error.h>
  29 #include <vlibapi/api.h>
  30
  31
  32 #define SNAT_UDP_TIMEOUT 300
  33 #define SNAT_TCP_TRANSITORY_TIMEOUT 240
  34 #define SNAT_TCP_ESTABLISHED_TIMEOUT 7440
  35 #define SNAT_ICMP_TIMEOUT 60
  36
  37 /* Key */
  38 typedef struct {
  39   union
  40   {
  41     struct
  42     {
  43       ip4_address_t addr;
  44       u16 port;
  45       u16 protocol:3,
  46         fib_index:13;
  47     };
  48     u64 as_u64;
  49   };
  50 } snat_session_key_t;
  51
  52 typedef struct {
  53   union
  54   {
  55     struct
  56     {
  57       ip4_address_t ext_host_addr;
  58       u16 ext_host_port;
  59       u16 out_port;
  60     };
  61     u64 as_u64;
  62   };
  63 } snat_det_out_key_t;
  64
  65 typedef struct {
  66   union
  67   {
  68     struct
  69     {
  70       ip4_address_t addr;
  71       u32 fib_index;
  72     };
  73     u64 as_u64;
  74   };
  75 } snat_user_key_t;
  76
  77 typedef struct {
  78   union
  79   {
  80     struct
  81     {
  82       ip4_address_t addr;
  83       u16 port;
  84       u16 fib_index;
  85     };
  86     u64 as_u64;
  87   };
  88 } snat_worker_key_t;
  89
  90
  91 #define foreach_snat_protocol \
  92   _(UDP, 0, udp, "udp")       \
  93   _(TCP, 1, tcp, "tcp")       \
  94   _(ICMP, 2, icmp, "icmp")
  95
  96 typedef enum {
  97 #define _(N, i, n, s) SNAT_PROTOCOL_##N = i,
  98   foreach_snat_protocol
  99 #undef _
 100 } snat_protocol_t;
 101
 102
 103 #define foreach_snat_session_state          \
 104   _(0, UNKNOWN, "unknown")                 \
 105   _(1, UDP_ACTIVE, "udp-active")           \
 106   _(2, TCP_SYN_SENT, "tcp-syn-sent")       \
 107   _(3, TCP_ESTABLISHED, "tcp-established") \
 108   _(4, TCP_FIN_WAIT, "tcp-fin-wait")       \
 109   _(5, TCP_CLOSE_WAIT, "tcp-close-wait")   \
 110   _(6, TCP_LAST_ACK, "tcp-last-ack")       \
 111   _(7, ICMP_ACTIVE, "icmp-active")
 112
 113 typedef enum {
 114 #define _(v, N, s) SNAT_SESSION_##N = v,
 115   foreach_snat_session_state
 116 #undef _
 117 } snat_session_state_t;
 118
 119
 120 #define SNAT_SESSION_FLAG_STATIC_MAPPING 1
 121
 122 typedef CLIB_PACKED(struct {
 123   snat_session_key_t out2in;    /* 0-15 */
 124
 125   snat_session_key_t in2out;    /* 16-31 */
 126
 127   u32 flags;                    /* 32-35 */
 128
 129   /* per-user translations */
 130   u32 per_user_index;           /* 36-39 */
 131
 132   u32 per_user_list_head_index; /* 40-43 */
 133
 134   /* Last heard timer */
 135   f64 last_heard;               /* 44-51 */
 136
 137   u64 total_bytes;              /* 52-59 */
 138
 139   u32 total_pkts;               /* 60-63 */
 140
 141   /* Outside address */
 142   u32 outside_address_index;    /* 64-67 */
 143
 144 }) snat_session_t;
 145
 146
 147 typedef struct {
 148   ip4_address_t addr;
 149   u32 fib_index;
 150   u32 sessions_per_user_list_head_index;
 151   u32 nsessions;
 152   u32 nstaticsessions;
 153 } snat_user_t;
 154
 155 typedef struct {
 156   ip4_address_t addr;
 157   u32 fib_index;
 158 #define _(N, i, n, s) \
 159   u32 busy_##n##_ports; \
 160   uword * busy_##n##_port_bitmap;
 161   foreach_snat_protocol
 162 #undef _
 163 } snat_address_t;
 164
 165 typedef struct {
 166   u16 in_port;
 167   snat_det_out_key_t out;
 168   u8 state;
 169   u32 expire;
 170 } snat_det_session_t;
 171
 172 typedef struct {
 173   ip4_address_t in_addr;
 174   u8 in_plen;
 175   ip4_address_t out_addr;
 176   u8 out_plen;
 177   u32 sharing_ratio;
 178   u16 ports_per_host;
 179   u32 ses_num;
 180   /* vector of sessions */
 181   snat_det_session_t * sessions;
 182 } snat_det_map_t;
 183
 184 typedef struct {
 185   ip4_address_t local_addr;
 186   ip4_address_t external_addr;
 187   u16 local_port;
 188   u16 external_port;
 189   u8 addr_only;
 190   u32 vrf_id;
 191   u32 fib_index;
 192   snat_protocol_t proto;
 193 } snat_static_mapping_t;
 194
 195 typedef struct {
 196   u32 sw_if_index;
 197   u8 is_inside;
 198 } snat_interface_t;
 199
 200 typedef struct {
 201   ip4_address_t l_addr;
 202   u16 l_port;
 203   u16 e_port;
 204   u32 sw_if_index;
 205   u32 vrf_id;
 206   snat_protocol_t proto;
 207   int addr_only;
 208   int is_add;
 209 } snat_static_map_resolve_t;
 210
 211 typedef struct {
 212   /* User pool */
 213   snat_user_t * users;
 214
 215   /* Session pool */
 216   snat_session_t * sessions;
 217
 218   /* Pool of doubly-linked list elements */
 219   dlist_elt_t * list_pool;
 220 } snat_main_per_thread_data_t;
 221
 222 struct snat_main_s;
 223
 224 typedef u32 snat_icmp_match_function_t (struct snat_main_s *sm,
 225                                         vlib_node_runtime_t *node,
 226                                         u32 thread_index,
 227                                         vlib_buffer_t *b0,
 228                                         u8 *p_proto,
 229                                         snat_session_key_t *p_value,
 230                                         u8 *p_dont_translate,
 231                                         void *d,
 232                                         void *e);
 233
 234 typedef u32 (snat_get_worker_function_t) (ip4_header_t * ip, u32 rx_fib_index);
 235
 236 typedef struct snat_main_s {
 237   /* Main lookup tables */
 238   clib_bihash_8_8_t out2in;
 239   clib_bihash_8_8_t in2out;
 240
 241   /* Find-a-user => src address lookup */
 242   clib_bihash_8_8_t user_hash;
 243
 244   /* Non-translated packets worker lookup => src address + VRF */
 245   clib_bihash_8_8_t worker_by_in;
 246
 247   /* Translated packets worker lookup => IP address + port number */
 248   clib_bihash_8_8_t worker_by_out;
 249
 250   snat_icmp_match_function_t * icmp_match_in2out_cb;
 251   snat_icmp_match_function_t * icmp_match_out2in_cb;
 252
 253   u32 num_workers;
 254   u32 first_worker_index;
 255   u32 next_worker;
 256   u32 * workers;
 257   snat_get_worker_function_t * worker_in2out_cb;
 258   snat_get_worker_function_t * worker_out2in_cb;
 259
 260   /* Per thread data */
 261   snat_main_per_thread_data_t * per_thread_data;
 262
 263   /* Find a static mapping by local */
 264   clib_bihash_8_8_t static_mapping_by_local;
 265
 266   /* Find a static mapping by external */
 267   clib_bihash_8_8_t static_mapping_by_external;
 268
 269   /* Static mapping pool */
 270   snat_static_mapping_t * static_mappings;
 271
 272   /* Interface pool */
 273   snat_interface_t * interfaces;
 274
 275   /* Vector of outside addresses */
 276   snat_address_t * addresses;
 277
 278   /* sw_if_indices whose intfc addresses should be auto-added */
 279   u32 * auto_add_sw_if_indices;
 280
 281   /* vector of interface address static mappings to resolve. */
 282   snat_static_map_resolve_t *to_resolve;
 283
 284   /* Randomize port allocation order */
 285   u32 random_seed;
 286
 287   /* Worker handoff index */
 288   u32 fq_in2out_index;
 289   u32 fq_out2in_index;
 290
 291   /* in2out and out2in node index */
 292   u32 in2out_node_index;
 293   u32 out2in_node_index;
 294
 295   /* Deterministic NAT */
 296   snat_det_map_t * det_maps;
 297
 298   /* Config parameters */
 299   u8 static_mapping_only;
 300   u8 static_mapping_connection_tracking;
 301   u8 deterministic;
 302   u32 translation_buckets;
 303   u32 translation_memory_size;
 304   u32 user_buckets;
 305   u32 user_memory_size;
 306   u32 max_translations_per_user;
 307   u32 outside_vrf_id;
 308   u32 outside_fib_index;
 309   u32 inside_vrf_id;
 310   u32 inside_fib_index;
 311
 312   /* tenant VRF aware address pool activation flag */
 313   u8 vrf_mode;
 314
 315   /* values of various timeouts */
 316   u32 udp_timeout;
 317   u32 tcp_established_timeout;
 318   u32 tcp_transitory_timeout;
 319   u32 icmp_timeout;
 320
 321   /* API message ID base */
 322   u16 msg_id_base;
 323
 324   /* convenience */
 325   vlib_main_t * vlib_main;
 326   vnet_main_t * vnet_main;
 327   ip4_main_t * ip4_main;
 328   ip_lookup_main_t * ip4_lookup_main;
 329   api_main_t * api_main;
 330 } snat_main_t;
 331
 332 extern snat_main_t snat_main;
 333 extern vlib_node_registration_t snat_in2out_node;
 334 extern vlib_node_registration_t snat_out2in_node;
 335 extern vlib_node_registration_t snat_in2out_fast_node;
 336 extern vlib_node_registration_t snat_out2in_fast_node;
 337 extern vlib_node_registration_t snat_in2out_worker_handoff_node;
 338 extern vlib_node_registration_t snat_out2in_worker_handoff_node;
 339 extern vlib_node_registration_t snat_det_in2out_node;
 340 extern vlib_node_registration_t snat_det_out2in_node;
 341
 342 void snat_free_outside_address_and_port (snat_main_t * sm,
 343                                          snat_session_key_t * k,
 344                                          u32 address_index);
 345
 346 int snat_alloc_outside_address_and_port (snat_main_t * sm,
 347                                          u32 fib_index,
 348                                          snat_session_key_t * k,
 349                                          u32 * address_indexp);
 350
 351 int snat_static_mapping_match (snat_main_t * sm,
 352                                snat_session_key_t match,
 353                                snat_session_key_t * mapping,
 354                                u8 by_external,
 355                                u8 *is_addr_only);
 356
 357 void snat_add_del_addr_to_fib (ip4_address_t * addr,
 358                                u8 p_len,
 359                                u32 sw_if_index,
 360                                int is_add);
 361
 362 format_function_t format_snat_user;
 363
 364 typedef struct {
 365   u32 cached_sw_if_index;
 366   u32 cached_ip4_address;
 367 } snat_runtime_t;
 368
 369 /** \brief Check if SNAT session is created from static mapping.
 370     @param s SNAT session
 371     @return 1 if SNAT session is created from static mapping otherwise 0
 372 */
 373 #define snat_is_session_static(s) s->flags & SNAT_SESSION_FLAG_STATIC_MAPPING
 374
 375 /*
 376  * Why is this here? Because we don't need to touch this layer to
 377  * simply reply to an icmp. We need to change id to a unique
 378  * value to NAT an echo request/reply.
 379  */
 380
 381 typedef struct {
 382   u16 identifier;
 383   u16 sequence;
 384 } icmp_echo_header_t;
 385
 386 always_inline snat_protocol_t
 387 ip_proto_to_snat_proto (u8 ip_proto)
 388 {
 389   snat_protocol_t snat_proto = ~0;
 390
 391   snat_proto = (ip_proto == IP_PROTOCOL_UDP) ? SNAT_PROTOCOL_UDP : snat_proto;
 392   snat_proto = (ip_proto == IP_PROTOCOL_TCP) ? SNAT_PROTOCOL_TCP : snat_proto;
 393   snat_proto = (ip_proto == IP_PROTOCOL_ICMP) ? SNAT_PROTOCOL_ICMP : snat_proto;
 394
 395   return snat_proto;
 396 }
 397
 398 always_inline u8
 399 snat_proto_to_ip_proto (snat_protocol_t snat_proto)
 400 {
 401   u8 ip_proto = ~0;
 402
 403   ip_proto = (snat_proto == SNAT_PROTOCOL_UDP) ? IP_PROTOCOL_UDP : ip_proto;
 404   ip_proto = (snat_proto == SNAT_PROTOCOL_TCP) ? IP_PROTOCOL_TCP : ip_proto;
 405   ip_proto = (snat_proto == SNAT_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP : ip_proto;
 406
 407   return ip_proto;
 408 }
 409
 410 typedef struct {
 411   u16 src_port, dst_port;
 412 } tcp_udp_header_t;
 413
 414 u32 icmp_match_in2out_fast(snat_main_t *sm, vlib_node_runtime_t *node,
 415                            u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
 416                            snat_session_key_t *p_value,
 417                            u8 *p_dont_translate, void *d, void *e);
 418 u32 icmp_match_in2out_slow(snat_main_t *sm, vlib_node_runtime_t *node,
 419                            u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
 420                            snat_session_key_t *p_value,
 421                            u8 *p_dont_translate, void *d, void *e);
 422 u32 icmp_match_in2out_det(snat_main_t *sm, vlib_node_runtime_t *node,
 423                           u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
 424                           snat_session_key_t *p_value,
 425                           u8 *p_dont_translate, void *d, void *e);
 426 u32 icmp_match_out2in_fast(snat_main_t *sm, vlib_node_runtime_t *node,
 427                            u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
 428                            snat_session_key_t *p_value,
 429                            u8 *p_dont_translate, void *d, void *e);
 430 u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
 431                            u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
 432                            snat_session_key_t *p_value,
 433                            u8 *p_dont_translate, void *d, void *e);
 434 u32 icmp_match_out2in_det(snat_main_t *sm, vlib_node_runtime_t *node,
 435                           u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
 436                           snat_session_key_t *p_value,
 437                           u8 *p_dont_translate, void *d, void *e);
 438
 439 static_always_inline u8
 440 icmp_is_error_message (icmp46_header_t * icmp)
 441 {
 442   switch(icmp->type)
 443     {
 444     case ICMP4_destination_unreachable:
 445     case ICMP4_time_exceeded:
 446     case ICMP4_parameter_problem:
 447     case ICMP4_source_quench:
 448     case ICMP4_redirect:
 449     case ICMP4_alternate_host_address:
 450       return 1;
 451     }
 452   return 0;
 453 }
 454
 455 static_always_inline u8
 456 is_interface_addr(snat_main_t *sm, vlib_node_runtime_t *node, u32 sw_if_index0,
 457                   u32 ip4_addr)
 458 {
 459   snat_runtime_t *rt = (snat_runtime_t *) node->runtime_data;
 460   ip4_address_t * first_int_addr;
 461
 462   if (PREDICT_FALSE(rt->cached_sw_if_index != sw_if_index0))
 463     {
 464       first_int_addr =
 465         ip4_interface_first_address (sm->ip4_main, sw_if_index0,
 466                                      0 /* just want the address */);
 467       rt->cached_sw_if_index = sw_if_index0;
 468       if (first_int_addr)
 469         rt->cached_ip4_address = first_int_addr->as_u32;
 470       else
 471         rt->cached_ip4_address = 0;
 472     }
 473
 474   if (PREDICT_FALSE(ip4_addr == rt->cached_ip4_address))
 475     return 1;
 476   else
 477     return 0;
 478 }
 479
 480 #endif /* __included_snat_h__ */