nat.h

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/*
 * nat.h - NAT plugin definitions
 *
 * Copyright (c) 2016 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef __included_nat_h__
#define __included_nat_h__

#include <vnet/vnet.h>
#include <vnet/ip/ip.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/ip/icmp46_packet.h>
#include <vnet/api_errno.h>
#include <vppinfra/bihash_8_8.h>
#include <vppinfra/bihash_16_8.h>
#include <vppinfra/dlist.h>
#include <vppinfra/error.h>
#include <vlibapi/api.h>
#include <vlib/log.h>


#define SNAT_UDP_TIMEOUT 300
#define SNAT_UDP_TIMEOUT_MIN 120
#define SNAT_TCP_TRANSITORY_TIMEOUT 240
#define SNAT_TCP_ESTABLISHED_TIMEOUT 7440
#define SNAT_TCP_INCOMING_SYN 6
#define SNAT_ICMP_TIMEOUT 60

#define NAT_FQ_NELTS 64

#define SNAT_FLAG_HAIRPINNING (1 << 0)

/* Key */
typedef struct {
  union
  {
    struct
    {
      ip4_address_t addr;
      u16 port;
      u16 protocol:3,
        fib_index:13;
    };
    u64 as_u64;
  };
} snat_session_key_t;

typedef struct {
  union
  {
    struct
    {
      ip4_address_t l_addr;
      ip4_address_t r_addr;
      u32 proto:8,
          fib_index:24;
      u16 l_port;
      u16 r_port;
    };
    u64 as_u64[2];
  };
} nat_ed_ses_key_t;

typedef struct {
  union
  {
    struct
    {
      ip4_address_t ext_host_addr;
      u16 ext_host_port;
      u16 out_port;
    };
    u64 as_u64;
  };
} snat_det_out_key_t;

typedef struct {
  union
  {
    struct
    {
      ip4_address_t addr;
      u32 fib_index;
    };
    u64 as_u64;
  };
} snat_user_key_t;


#define foreach_snat_protocol \
  _(UDP, 0, udp, "udp")       \
  _(TCP, 1, tcp, "tcp")       \
  _(ICMP, 2, icmp, "icmp")

typedef enum {
#define _(N, i, n, s) SNAT_PROTOCOL_##N = i,
  foreach_snat_protocol
#undef _
} snat_protocol_t;


#define foreach_snat_session_state          \
  _(0, UNKNOWN, "unknown")                 \
  _(1, UDP_ACTIVE, "udp-active")           \
  _(2, TCP_SYN_SENT, "tcp-syn-sent")       \
  _(3, TCP_ESTABLISHED, "tcp-established") \
  _(4, TCP_FIN_WAIT, "tcp-fin-wait")       \
  _(5, TCP_CLOSE_WAIT, "tcp-close-wait")   \
  _(6, TCP_CLOSING, "tcp-closing")         \
  _(7, TCP_LAST_ACK, "tcp-last-ack")       \
  _(8, TCP_CLOSED, "tcp-closed")           \
  _(9, ICMP_ACTIVE, "icmp-active")

typedef enum {
#define _(v, N, s) SNAT_SESSION_##N = v,
  foreach_snat_session_state
#undef _
} snat_session_state_t;

#define NAT44_SES_I2O_FIN 1
#define NAT44_SES_O2I_FIN 2
#define NAT44_SES_I2O_FIN_ACK 4
#define NAT44_SES_O2I_FIN_ACK 8

#define nat44_is_ses_closed(s) s->state == 0xf

#define SNAT_SESSION_FLAG_STATIC_MAPPING       1
#define SNAT_SESSION_FLAG_UNKNOWN_PROTO        2
#define SNAT_SESSION_FLAG_LOAD_BALANCING       4
#define SNAT_SESSION_FLAG_TWICE_NAT            8
#define SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT   16
#define SNAT_SESSION_FLAG_FWD_BYPASS           32

#define NAT_INTERFACE_FLAG_IS_INSIDE 1
#define NAT_INTERFACE_FLAG_IS_OUTSIDE 2

typedef CLIB_PACKED(struct {
  snat_session_key_t out2in;    /* 0-15 */

  snat_session_key_t in2out;    /* 16-31 */

  u32 flags;                    /* 32-35 */

  /* per-user translations */
  u32 per_user_index;           /* 36-39 */

  u32 per_user_list_head_index; /* 40-43 */

  /* Last heard timer */
  f64 last_heard;               /* 44-51 */

  u64 total_bytes;              /* 52-59 */

  u32 total_pkts;               /* 60-63 */

  /* Outside address */
  u32 outside_address_index;    /* 64-67 */

  /* External host address and port */
  ip4_address_t ext_host_addr;  /* 68-71 */
  u16 ext_host_port;            /* 72-73 */

  /* External hos address and port after translation */
  ip4_address_t ext_host_nat_addr; /* 74-77 */
  u16 ext_host_nat_port;           /* 78-79 */

  /* TCP session state */
  u8 state;
  u32 i2o_fin_seq;
  u32 o2i_fin_seq;
}) snat_session_t;


typedef struct {
  ip4_address_t addr;
  u32 fib_index;
  u32 sessions_per_user_list_head_index;
  u32 nsessions;
  u32 nstaticsessions;
} snat_user_t;

typedef struct {
  ip4_address_t addr;
  u32 fib_index;
#define _(N, i, n, s) \
  u16 busy_##n##_ports; \
  u16 * busy_##n##_ports_per_thread; \
  uword * busy_##n##_port_bitmap;
  foreach_snat_protocol
#undef _
} snat_address_t;

typedef struct {
  u16 in_port;
  snat_det_out_key_t out;
  u8 state;
  u32 expire;
} snat_det_session_t;

typedef struct {
  ip4_address_t in_addr;
  u8 in_plen;
  ip4_address_t out_addr;
  u8 out_plen;
  u32 sharing_ratio;
  u16 ports_per_host;
  u32 ses_num;
  /* vector of sessions */
  snat_det_session_t * sessions;
} snat_det_map_t;

typedef struct {
  ip4_address_t addr;
  u16 port;
  u8 probability;
  u8 prefix;
} nat44_lb_addr_port_t;

typedef enum {
  TWICE_NAT_DISABLED,
  TWICE_NAT,
  TWICE_NAT_SELF,
} twice_nat_type_t;

typedef struct {
  ip4_address_t local_addr;
  ip4_address_t external_addr;
  u16 local_port;
  u16 external_port;
  u8 addr_only;
  twice_nat_type_t twice_nat;
  u8 out2in_only;
  u32 vrf_id;
  u32 fib_index;
  snat_protocol_t proto;
  u32 *workers;
  u8 *tag;
  nat44_lb_addr_port_t *locals;
} snat_static_mapping_t;

typedef struct {
  u32 sw_if_index;
  u8 flags;
} snat_interface_t;

typedef struct {
  ip4_address_t l_addr;
  u16 l_port;
  u16 e_port;
  u32 sw_if_index;
  u32 vrf_id;
  snat_protocol_t proto;
  int addr_only;
  int twice_nat;
  int is_add;
  u8 *tag;
} snat_static_map_resolve_t;

typedef struct {
  /* Main lookup tables */
  clib_bihash_8_8_t out2in;
  clib_bihash_8_8_t in2out;

  /* Endpoint dependent sessions lookup tables */
  clib_bihash_16_8_t out2in_ed;
  clib_bihash_16_8_t in2out_ed;

  /* Find-a-user => src address lookup */
  clib_bihash_8_8_t user_hash;

  /* User pool */
  snat_user_t * users;

  /* Session pool */
  snat_session_t * sessions;

  /* Pool of doubly-linked list elements */
  dlist_elt_t * list_pool;

  u32 snat_thread_index;
} snat_main_per_thread_data_t;

struct snat_main_s;

typedef u32 snat_icmp_match_function_t (struct snat_main_s *sm,
                                        vlib_node_runtime_t *node,
                                        u32 thread_index,
                                        vlib_buffer_t *b0,
                                        ip4_header_t *ip0,
                                        u8 *p_proto,
                                        snat_session_key_t *p_value,
                                        u8 *p_dont_translate,
                                        void *d,
                                        void *e);

typedef u32 (snat_get_worker_function_t) (ip4_header_t * ip, u32 rx_fib_index);

typedef int nat_alloc_out_addr_and_port_function_t (snat_address_t * addresses,
                                                    u32 fib_index,
                                                    u32 thread_index,
                                                    snat_session_key_t * k,
                                                    u32 * address_indexp,
                                                    u16 port_per_thread,
                                                    u32 snat_thread_index);

typedef struct snat_main_s {
  snat_icmp_match_function_t * icmp_match_in2out_cb;
  snat_icmp_match_function_t * icmp_match_out2in_cb;

  u32 num_workers;
  u32 first_worker_index;
  u32 * workers;
  snat_get_worker_function_t * worker_in2out_cb;
  snat_get_worker_function_t * worker_out2in_cb;
  u16 port_per_thread;
  u32 num_snat_thread;

  /* Per thread data */
  snat_main_per_thread_data_t * per_thread_data;

  /* Find a static mapping by local */
  clib_bihash_8_8_t static_mapping_by_local;

  /* Find a static mapping by external */
  clib_bihash_8_8_t static_mapping_by_external;

  /* Static mapping pool */
  snat_static_mapping_t * static_mappings;

  /* Interface pool */
  snat_interface_t * interfaces;
  snat_interface_t * output_feature_interfaces;

  /* Vector of outside addresses */
  snat_address_t * addresses;
  nat_alloc_out_addr_and_port_function_t *alloc_addr_and_port;
  u8 psid_offset;
  u8 psid_length;
  u16 psid;

  /* Vector of twice NAT addresses for extenal hosts */
  snat_address_t * twice_nat_addresses;

  /* sw_if_indices whose intfc addresses should be auto-added */
  u32 * auto_add_sw_if_indices;
  u32 * auto_add_sw_if_indices_twice_nat;

  /* vector of interface address static mappings to resolve. */
  snat_static_map_resolve_t *to_resolve;

  /* Randomize port allocation order */
  u32 random_seed;

  /* Worker handoff index */
  u32 fq_in2out_index;
  u32 fq_in2out_output_index;
  u32 fq_out2in_index;

  /* in2out and out2in node index */
  u32 in2out_node_index;
  u32 in2out_output_node_index;
  u32 out2in_node_index;
  u32 error_node_index;

  /* Deterministic NAT */
  snat_det_map_t * det_maps;

  /* If forwarding is enabled */
  u8 forwarding_enabled;

  /* Config parameters */
  u8 static_mapping_only;
  u8 static_mapping_connection_tracking;
  u8 deterministic;
  u8 out2in_dpo;
  u8 endpoint_dependent;
  u32 translation_buckets;
  u32 translation_memory_size;
  u32 max_translations;
  u32 user_buckets;
  u32 user_memory_size;
  u32 max_translations_per_user;
  u32 outside_vrf_id;
  u32 outside_fib_index;
  u32 inside_vrf_id;
  u32 inside_fib_index;

  /* values of various timeouts */
  u32 udp_timeout;
  u32 tcp_established_timeout;
  u32 tcp_transitory_timeout;
  u32 icmp_timeout;

  /* API message ID base */
  u16 msg_id_base;

  /* log class */
  vlib_log_class_t log_class;

  /* convenience */
  vlib_main_t * vlib_main;
  vnet_main_t * vnet_main;
  ip4_main_t * ip4_main;
  ip_lookup_main_t * ip4_lookup_main;
  api_main_t * api_main;
} snat_main_t;

extern snat_main_t snat_main;
extern vlib_node_registration_t snat_in2out_node;
extern vlib_node_registration_t snat_in2out_output_node;
extern vlib_node_registration_t snat_out2in_node;
extern vlib_node_registration_t snat_in2out_fast_node;
extern vlib_node_registration_t snat_out2in_fast_node;
extern vlib_node_registration_t snat_in2out_worker_handoff_node;
extern vlib_node_registration_t snat_in2out_output_worker_handoff_node;
extern vlib_node_registration_t snat_out2in_worker_handoff_node;
extern vlib_node_registration_t snat_det_in2out_node;
extern vlib_node_registration_t snat_det_out2in_node;
extern vlib_node_registration_t snat_hairpin_dst_node;
extern vlib_node_registration_t snat_hairpin_src_node;
extern vlib_node_registration_t nat44_ed_in2out_node;
extern vlib_node_registration_t nat44_ed_in2out_output_node;
extern vlib_node_registration_t nat44_ed_out2in_node;
extern vlib_node_registration_t nat44_ed_hairpin_dst_node;
extern vlib_node_registration_t nat44_ed_hairpin_src_node;
extern vlib_node_registration_t nat44_ed_in2out_worker_handoff_node;
extern vlib_node_registration_t nat44_ed_in2out_output_worker_handoff_node;
extern vlib_node_registration_t nat44_ed_out2in_worker_handoff_node;

void snat_free_outside_address_and_port (snat_address_t * addresses,
                                         u32 thread_index,
                                         snat_session_key_t * k,
                                         u32 address_index);

int snat_alloc_outside_address_and_port (snat_address_t * addresses,
                                         u32 fib_index,
                                         u32 thread_index,
                                         snat_session_key_t * k,
                                         u32 * address_indexp,
                                         u16 port_per_thread,
                                         u32 snat_thread_index);

int snat_static_mapping_match (snat_main_t * sm,
                               snat_session_key_t match,
                               snat_session_key_t * mapping,
                               u8 by_external,
                               u8 *is_addr_only,
                               twice_nat_type_t *twice_nat,
                               u8 *lb);

void snat_add_del_addr_to_fib (ip4_address_t * addr,
                               u8 p_len,
                               u32 sw_if_index,
                               int is_add);

format_function_t format_snat_user;
format_function_t format_snat_static_mapping;
format_function_t format_snat_static_map_to_resolve;
format_function_t format_snat_session;
format_function_t format_det_map_ses;

typedef struct {
  u32 cached_sw_if_index;
  u32 cached_ip4_address;
} snat_runtime_t;

/** \brief Check if SNAT session is created from static mapping.
    @param s SNAT session
    @return 1 if SNAT session is created from static mapping otherwise 0
*/
#define snat_is_session_static(s) (s->flags & SNAT_SESSION_FLAG_STATIC_MAPPING)

/** \brief Check if SNAT session for unknown protocol.
    @param s SNAT session
    @return 1 if SNAT session for unknown protocol otherwise 0
*/
#define snat_is_unk_proto_session(s) (s->flags & SNAT_SESSION_FLAG_UNKNOWN_PROTO)

/** \brief Check if NAT session is twice NAT.
    @param s NAT session
    @return 1 if NAT session is twice NAT
*/
#define is_twice_nat_session(s) (s->flags & SNAT_SESSION_FLAG_TWICE_NAT)

/** \brief Check if NAT session is load-balancing.
    @param s NAT session
    @return 1 if NAT session is load-balancing
*/
#define is_lb_session(s) (s->flags & SNAT_SESSION_FLAG_LOAD_BALANCING)

/** \brief Check if NAT session is forwarding bypass.
    @param s NAT session
    @return 1 if NAT session is load-balancing
*/
#define is_fwd_bypass_session(s) (s->flags & SNAT_SESSION_FLAG_FWD_BYPASS)

/** \brief Check if NAT session is endpoint dependent.
    @param s NAT session
    @return 1 if NAT session is endpoint dependent
*/
#define is_ed_session(s) (s->flags & SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT)

#define nat_interface_is_inside(i) i->flags & NAT_INTERFACE_FLAG_IS_INSIDE
#define nat_interface_is_outside(i) i->flags & NAT_INTERFACE_FLAG_IS_OUTSIDE

#define nat_log_err(...) \
  vlib_log(VLIB_LOG_LEVEL_ERR, snat_main.log_class, __VA_ARGS__)
#define nat_log_warn(...) \
  vlib_log(VLIB_LOG_LEVEL_WARNING, snat_main.log_class, __VA_ARGS__)
#define nat_log_notice(...) \
  vlib_log(VLIB_LOG_LEVEL_NOTICE, snat_main.log_class, __VA_ARGS__)
#define nat_log_info(...) \
  vlib_log(VLIB_LOG_LEVEL_INFO, snat_main.log_class, __VA_ARGS__)
#define nat_log_debug(...)\
  vlib_log(VLIB_LOG_LEVEL_DEBUG, snat_main.log_class, __VA_ARGS__)

/*
 * Why is this here? Because we don't need to touch this layer to
 * simply reply to an icmp. We need to change id to a unique
 * value to NAT an echo request/reply.
 */

typedef struct {
  u16 identifier;
  u16 sequence;
} icmp_echo_header_t;

typedef struct {
  u16 src_port, dst_port;
} tcp_udp_header_t;

u32 icmp_match_in2out_fast(snat_main_t *sm, vlib_node_runtime_t *node,
                           u32 thread_index, vlib_buffer_t *b0,
                           ip4_header_t *ip0, u8 *p_proto,
                           snat_session_key_t *p_value,
                           u8 *p_dont_translate, void *d, void *e);
u32 icmp_match_in2out_slow(snat_main_t *sm, vlib_node_runtime_t *node,
                           u32 thread_index, vlib_buffer_t *b0,
                           ip4_header_t *ip0, u8 *p_proto,
                           snat_session_key_t *p_value,
                           u8 *p_dont_translate, void *d, void *e);
u32 icmp_match_in2out_det(snat_main_t *sm, vlib_node_runtime_t *node,
                          u32 thread_index, vlib_buffer_t *b0,
                          ip4_header_t *ip0, u8 *p_proto,
                          snat_session_key_t *p_value,
                          u8 *p_dont_translate, void *d, void *e);
u32 icmp_match_in2out_ed(snat_main_t *sm, vlib_node_runtime_t *node,
                         u32 thread_index, vlib_buffer_t *b0,
                         ip4_header_t *ip0, u8 *p_proto,
                         snat_session_key_t *p_value,
                         u8 *p_dont_translate, void *d, void *e);
u32 icmp_match_out2in_fast(snat_main_t *sm, vlib_node_runtime_t *node,
                           u32 thread_index, vlib_buffer_t *b0,
                           ip4_header_t *ip0, u8 *p_proto,
                           snat_session_key_t *p_value,
                           u8 *p_dont_translate, void *d, void *e);
u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
                           u32 thread_index, vlib_buffer_t *b0,
                           ip4_header_t *ip0, u8 *p_proto,
                           snat_session_key_t *p_value,
                           u8 *p_dont_translate, void *d, void *e);
u32 icmp_match_out2in_det(snat_main_t *sm, vlib_node_runtime_t *node,
                          u32 thread_index, vlib_buffer_t *b0,
                          ip4_header_t *ip0, u8 *p_proto,
                          snat_session_key_t *p_value,
                          u8 *p_dont_translate, void *d, void *e);
u32 icmp_match_out2in_ed(snat_main_t *sm, vlib_node_runtime_t *node,
                         u32 thread_index, vlib_buffer_t *b0,
                         ip4_header_t *ip0, u8 *p_proto,
                         snat_session_key_t *p_value,
                         u8 *p_dont_translate, void *d, void *e);
void increment_v4_address(ip4_address_t * a);
int snat_add_address(snat_main_t *sm, ip4_address_t *addr, u32 vrf_id,
                     u8 twice_nat);
int snat_del_address(snat_main_t *sm, ip4_address_t addr, u8 delete_sm,
                     u8 twice_nat);
void nat44_add_del_address_dpo (ip4_address_t addr, u8 is_add);
int snat_add_static_mapping(ip4_address_t l_addr, ip4_address_t e_addr,
                            u16 l_port, u16 e_port, u32 vrf_id, int addr_only,
                            u32 sw_if_index, snat_protocol_t proto, int is_add,
                            twice_nat_type_t twice_nat, u8 out2in_only,
                            u8 *tag);
clib_error_t * snat_api_init(vlib_main_t * vm, snat_main_t * sm);
int snat_set_workers (uword * bitmap);
int snat_interface_add_del(u32 sw_if_index, u8 is_inside, int is_del);
int snat_interface_add_del_output_feature(u32 sw_if_index, u8 is_inside,
                                          int is_del);
int snat_add_interface_address(snat_main_t *sm, u32 sw_if_index, int is_del,
                               u8 twice_nat);
uword unformat_snat_protocol(unformat_input_t * input, va_list * args);
u8 * format_snat_protocol(u8 * s, va_list * args);
int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
                                     snat_protocol_t proto, u32 vrf_id,
                                     nat44_lb_addr_port_t *locals, u8 is_add,
                                     twice_nat_type_t twice_nat, u8 out2in_only,
                                     u8 *tag);
int nat44_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
                       snat_protocol_t proto, u32 vrf_id, int is_in);
int nat44_del_ed_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
                          ip4_address_t *eh_addr, u16 eh_port, u8 proto,
                          u32 vrf_id, int is_in);
void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
                            u32 thread_index);
snat_user_t * nat_user_get_or_create (snat_main_t *sm, ip4_address_t *addr,
                                      u32 fib_index, u32 thread_index);
snat_session_t * nat_session_alloc_or_recycle (snat_main_t *sm, snat_user_t *u,
                                               u32 thread_index);
void nat_set_alloc_addr_and_port_mape (u16 psid, u16 psid_offset,
                                       u16 psid_length);
void nat_set_alloc_addr_and_port_default (void);

#endif /* __included_snat_h__ */