src/plugins/nat/nat.h - fdio/vpp - Gitiles


 /*
  * 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>


 #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 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 fib_index;
       u16 l_port;
       u8 proto;
       u8 rsvd;
     };
     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_LAST_ACK, "tcp-last-ack")       \
   _(7, ICMP_ACTIVE, "icmp-active")

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


 #define SNAT_SESSION_FLAG_STATIC_MAPPING 1
 #define SNAT_SESSION_FLAG_UNKNOWN_PROTO  2
 #define SNAT_SESSION_FLAG_LOAD_BALANCING 4

 #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 */
   ip4_address_t ext_host_addr;  /* 68-71 */

 }) 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 struct {
   ip4_address_t local_addr;
   ip4_address_t external_addr;
   u16 local_port;
   u16 external_port;
   u8 addr_only;
   u32 vrf_id;
   u32 fib_index;
   snat_protocol_t proto;
   u32 worker_index;
   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 is_add;
 } snat_static_map_resolve_t;

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

   /* 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 struct snat_main_s {
   /* Endpoint address dependent sessions lookup tables */
   clib_bihash_16_8_t out2in_ed;
   clib_bihash_16_8_t in2out_ed;

   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 next_worker;
   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;

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

   /* 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;

   /* Deterministic NAT */
   snat_det_map_t * det_maps;

   /* Config parameters */
   u8 static_mapping_only;
   u8 static_mapping_connection_tracking;
   u8 deterministic;
   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;

   /* tenant VRF aware address pool activation flag */
   u8 vrf_mode;

   /* 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;

   /* 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;

 void snat_free_outside_address_and_port (snat_main_t * sm,
                                          u32 thread_index,
                                          snat_session_key_t * k,
                                          u32 address_index);

 int snat_alloc_outside_address_and_port (snat_main_t * sm,
                                          u32 fib_index,
                                          u32 thread_index,
                                          snat_session_key_t * k,
                                          u32 * address_indexp);

 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);

 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;

 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

 #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

 /*
  * 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;

 always_inline u32
 ip_proto_to_snat_proto (u8 ip_proto)
 {
   u32 snat_proto = ~0;

   snat_proto = (ip_proto == IP_PROTOCOL_UDP) ? SNAT_PROTOCOL_UDP : snat_proto;
   snat_proto = (ip_proto == IP_PROTOCOL_TCP) ? SNAT_PROTOCOL_TCP : snat_proto;
   snat_proto = (ip_proto == IP_PROTOCOL_ICMP) ? SNAT_PROTOCOL_ICMP : snat_proto;
   snat_proto = (ip_proto == IP_PROTOCOL_ICMP6) ? SNAT_PROTOCOL_ICMP : snat_proto;

   return snat_proto;
 }

 always_inline u8
 snat_proto_to_ip_proto (snat_protocol_t snat_proto)
 {
   u8 ip_proto = ~0;

   ip_proto = (snat_proto == SNAT_PROTOCOL_UDP) ? IP_PROTOCOL_UDP : ip_proto;
   ip_proto = (snat_proto == SNAT_PROTOCOL_TCP) ? IP_PROTOCOL_TCP : ip_proto;
   ip_proto = (snat_proto == SNAT_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP : ip_proto;

   return ip_proto;
 }

 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_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);
 void increment_v4_address(ip4_address_t * a);
 void snat_add_address(snat_main_t *sm, ip4_address_t *addr, u32 vrf_id);
 int snat_del_address(snat_main_t *sm, ip4_address_t addr, u8 delete_sm);
 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);
 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);
 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);
 int nat44_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
                        snat_protocol_t proto, u32 vrf_id, int is_in);

 static_always_inline u8
 icmp_is_error_message (icmp46_header_t * icmp)
 {
   switch(icmp->type)
     {
     case ICMP4_destination_unreachable:
     case ICMP4_time_exceeded:
     case ICMP4_parameter_problem:
     case ICMP4_source_quench:
     case ICMP4_redirect:
     case ICMP4_alternate_host_address:
       return 1;
     }
   return 0;
 }

 static_always_inline u8
 is_interface_addr(snat_main_t *sm, vlib_node_runtime_t *node, u32 sw_if_index0,
                   u32 ip4_addr)
 {
   snat_runtime_t *rt = (snat_runtime_t *) node->runtime_data;
   ip4_address_t * first_int_addr;

   if (PREDICT_FALSE(rt->cached_sw_if_index != sw_if_index0))
     {
       first_int_addr =
         ip4_interface_first_address (sm->ip4_main, sw_if_index0,
                                      0 /* just want the address */);
       rt->cached_sw_if_index = sw_if_index0;
       if (first_int_addr)
         rt->cached_ip4_address = first_int_addr->as_u32;
       else
         rt->cached_ip4_address = 0;
     }

   if (PREDICT_FALSE(ip4_addr == rt->cached_ip4_address))
     return 1;
   else
     return 0;
 }

 always_inline u8
 maximum_sessions_exceeded (snat_main_t *sm, u32 thread_index)
 {
   if (pool_elts (sm->per_thread_data[thread_index].sessions) >= sm->max_translations)
     return 1;

   return 0;
 }

 #endif /* __included_nat_h__ */

	/*
	* 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>


	#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 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 fib_index;
	u16 l_port;
	u8 proto;
	u8 rsvd;
	};
	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_LAST_ACK, "tcp-last-ack") \
	_(7, ICMP_ACTIVE, "icmp-active")

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


	#define SNAT_SESSION_FLAG_STATIC_MAPPING 1
	#define SNAT_SESSION_FLAG_UNKNOWN_PROTO 2
	#define SNAT_SESSION_FLAG_LOAD_BALANCING 4

	#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 */
	ip4_address_t ext_host_addr; /* 68-71 */

	}) 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 struct {
	ip4_address_t local_addr;
	ip4_address_t external_addr;
	u16 local_port;
	u16 external_port;
	u8 addr_only;
	u32 vrf_id;
	u32 fib_index;
	snat_protocol_t proto;
	u32 worker_index;
	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 is_add;
	} snat_static_map_resolve_t;

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

	/* 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 struct snat_main_s {
	/* Endpoint address dependent sessions lookup tables */
	clib_bihash_16_8_t out2in_ed;
	clib_bihash_16_8_t in2out_ed;

	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 next_worker;
	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;

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

	/* 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;

	/* Deterministic NAT */
	snat_det_map_t * det_maps;

	/* Config parameters */
	u8 static_mapping_only;
	u8 static_mapping_connection_tracking;
	u8 deterministic;
	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;

	/* tenant VRF aware address pool activation flag */
	u8 vrf_mode;

	/* 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;

	/* 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;

	void snat_free_outside_address_and_port (snat_main_t * sm,
	u32 thread_index,
	snat_session_key_t * k,
	u32 address_index);

	int snat_alloc_outside_address_and_port (snat_main_t * sm,
	u32 fib_index,
	u32 thread_index,
	snat_session_key_t * k,
	u32 * address_indexp);

	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);

	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;

	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

	#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

	/*
	* 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;

	always_inline u32
	ip_proto_to_snat_proto (u8 ip_proto)
	{
	u32 snat_proto = ~0;

	snat_proto = (ip_proto == IP_PROTOCOL_UDP) ? SNAT_PROTOCOL_UDP : snat_proto;
	snat_proto = (ip_proto == IP_PROTOCOL_TCP) ? SNAT_PROTOCOL_TCP : snat_proto;
	snat_proto = (ip_proto == IP_PROTOCOL_ICMP) ? SNAT_PROTOCOL_ICMP : snat_proto;
	snat_proto = (ip_proto == IP_PROTOCOL_ICMP6) ? SNAT_PROTOCOL_ICMP : snat_proto;

	return snat_proto;
	}

	always_inline u8
	snat_proto_to_ip_proto (snat_protocol_t snat_proto)
	{
	u8 ip_proto = ~0;

	ip_proto = (snat_proto == SNAT_PROTOCOL_UDP) ? IP_PROTOCOL_UDP : ip_proto;
	ip_proto = (snat_proto == SNAT_PROTOCOL_TCP) ? IP_PROTOCOL_TCP : ip_proto;
	ip_proto = (snat_proto == SNAT_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP : ip_proto;

	return ip_proto;
	}

	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_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);
	void increment_v4_address(ip4_address_t * a);
	void snat_add_address(snat_main_t sm, ip4_address_t addr, u32 vrf_id);
	int snat_del_address(snat_main_t *sm, ip4_address_t addr, u8 delete_sm);
	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);
	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);
	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);
	int nat44_del_session (snat_main_t sm, ip4_address_t addr, u16 port,
	snat_protocol_t proto, u32 vrf_id, int is_in);

	static_always_inline u8
	icmp_is_error_message (icmp46_header_t * icmp)
	{
	switch(icmp->type)
	{
	case ICMP4_destination_unreachable:
	case ICMP4_time_exceeded:
	case ICMP4_parameter_problem:
	case ICMP4_source_quench:
	case ICMP4_redirect:
	case ICMP4_alternate_host_address:
	return 1;
	}
	return 0;
	}

	static_always_inline u8
	is_interface_addr(snat_main_t sm, vlib_node_runtime_t node, u32 sw_if_index0,
	u32 ip4_addr)
	{
	snat_runtime_t rt = (snat_runtime_t ) node->runtime_data;
	ip4_address_t * first_int_addr;

	if (PREDICT_FALSE(rt->cached_sw_if_index != sw_if_index0))
	{
	first_int_addr =
	ip4_interface_first_address (sm->ip4_main, sw_if_index0,
	0 /* just want the address */);
	rt->cached_sw_if_index = sw_if_index0;
	if (first_int_addr)
	rt->cached_ip4_address = first_int_addr->as_u32;
	else
	rt->cached_ip4_address = 0;
	}

	if (PREDICT_FALSE(ip4_addr == rt->cached_ip4_address))
	return 1;
	else
	return 0;
	}

	always_inline u8
	maximum_sessions_exceeded (snat_main_t *sm, u32 thread_index)
	{
	if (pool_elts (sm->per_thread_data[thread_index].sessions) >= sm->max_translations)
	return 1;

	return 0;
	}

	#endif /* __included_nat_h__ */