NAT: Refactoring / Housekeeping (VPP-1415)

Change-Id: Ia3ce24cc94f9b2fb331ad62a4181ddcd41bc78ca
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 592 insertions, 220 deletions

diff --git a/src/plugins/nat/nat.h b/src/plugins/nat/nat.h
index 06a61626333..865d27efb5a 100644
--- a/src/plugins/nat/nat.h
+++ b/src/plugins/nat/nat.h
@@ -1,7 +1,4 @@
-
 /*
- * 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.
@@ -15,6 +12,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+/**
+ * @file NAT plugin global declarations
+ */
 #ifndef __included_nat_h__
 #define __included_nat_h__
 
@@ -30,40 +30,43 @@
 #include <vlibapi/api.h>
 #include <vlib/log.h>
 
-
+/* default session timeouts */
 #define SNAT_UDP_TIMEOUT 300
 #define SNAT_TCP_TRANSITORY_TIMEOUT 240
 #define SNAT_TCP_ESTABLISHED_TIMEOUT 7440
 #define SNAT_ICMP_TIMEOUT 60
 
+/* number of worker handoff frame queue elements */
 #define NAT_FQ_NELTS 64
 
+/* NAT buffer flags */
 #define SNAT_FLAG_HAIRPINNING (1 << 0)
 
-/* Key */
-typedef struct {
+/* session key (4-tuple) */
+typedef struct
+{
   union
   {
     struct
     {
       ip4_address_t addr;
       u16 port;
-      u16 protocol:3,
-        fib_index:13;
+      u16 protocol:3, fib_index:13;
     };
     u64 as_u64;
   };
 } snat_session_key_t;
 
-typedef struct {
+/* endpoint-dependent session key (6-tuple) */
+typedef struct
+{
   union
   {
     struct
     {
       ip4_address_t l_addr;
       ip4_address_t r_addr;
-      u32 proto:8,
-          fib_index:24;
+      u32 proto:8, fib_index:24;
       u16 l_port;
       u16 r_port;
     };
@@ -71,7 +74,9 @@ typedef struct {
   };
 } nat_ed_ses_key_t;
 
-typedef struct {
+/* deterministic session outside key */
+typedef struct
+{
   union
   {
     struct
@@ -84,7 +89,9 @@ typedef struct {
   };
 } snat_det_out_key_t;
 
-typedef struct {
+/* user (internal host) key */
+typedef struct
+{
   union
   {
     struct
@@ -96,29 +103,42 @@ typedef struct {
   };
 } snat_user_key_t;
 
+typedef struct
+{
+  u32 sw_if_index;
+  u32 next_index;
+  u8 cached;
+} nat44_reass_trace_t;
+
+/* External address and port allocation modes */
 #define foreach_nat_addr_and_port_alloc_alg \
   _(0, DEFAULT, "default")         \
   _(1, MAPE, "map-e")              \
   _(2, RANGE, "port-range")
 
-typedef enum {
+typedef enum
+{
 #define _(v, N, s) NAT_ADDR_AND_PORT_ALLOC_ALG_##N = v,
   foreach_nat_addr_and_port_alloc_alg
 #undef _
 } nat_addr_and_port_alloc_alg_t;
 
+
+/* Supported L4 protocols */
 #define foreach_snat_protocol \
   _(UDP, 0, udp, "udp")       \
   _(TCP, 1, tcp, "tcp")       \
   _(ICMP, 2, icmp, "icmp")
 
-typedef enum {
+typedef enum
+{
 #define _(N, i, n, s) SNAT_PROTOCOL_##N = i,
   foreach_snat_protocol
 #undef _
 } snat_protocol_t;
 
 
+/* Session state */
 #define foreach_snat_session_state          \
   _(0, UNKNOWN, "unknown")                 \
   _(1, UDP_ACTIVE, "udp-active")           \
@@ -131,12 +151,14 @@ typedef enum {
   _(8, TCP_CLOSED, "tcp-closed")           \
   _(9, ICMP_ACTIVE, "icmp-active")
 
-typedef enum {
+typedef enum
+{
 #define _(v, N, s) SNAT_SESSION_##N = v,
   foreach_snat_session_state
 #undef _
 } snat_session_state_t;
 
+/* Endpoint dependent TCP session state */
 #define NAT44_SES_I2O_FIN 1
 #define NAT44_SES_O2I_FIN 2
 #define NAT44_SES_I2O_FIN_ACK 4
@@ -144,8 +166,7 @@ typedef enum {
 #define NAT44_SES_I2O_SYN 16
 #define NAT44_SES_O2I_SYN 32
 
-#define nat44_is_ses_closed(s) s->state == 0xf
-
+/* Session flags */
 #define SNAT_SESSION_FLAG_STATIC_MAPPING       1
 #define SNAT_SESSION_FLAG_UNKNOWN_PROTO        2
 #define SNAT_SESSION_FLAG_LOAD_BALANCING       4
@@ -154,47 +175,51 @@ typedef enum {
 #define SNAT_SESSION_FLAG_FWD_BYPASS           32
 #define SNAT_SESSION_FLAG_AFFINITY             64
 
+/* NAT interface flags */
 #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 */
+/* *INDENT-OFF* */
+typedef CLIB_PACKED(struct
+{
+  /* Outside network key */
+  snat_session_key_t out2in;
 
-  snat_session_key_t in2out;    /* 16-31 */
+  /* Inside network key */
+  snat_session_key_t in2out;
 
-  u32 flags;                    /* 32-35 */
+  /* Flags */
+  u32 flags;
 
-  /* per-user translations */
-  u32 per_user_index;           /* 36-39 */
-
-  u32 per_user_list_head_index; /* 40-43 */
+  /* Per-user translations */
+  u32 per_user_index;
+  u32 per_user_list_head_index;
 
   /* Last heard timer */
-  f64 last_heard;               /* 44-51 */
-
-  u64 total_bytes;              /* 52-59 */
-
-  u32 total_pkts;               /* 60-63 */
+  f64 last_heard;
 
-  /* Outside address */
-  u32 outside_address_index;    /* 64-67 */
+  /* Counters */
+  u64 total_bytes;
+  u32 total_pkts;
 
   /* External host address and port */
-  ip4_address_t ext_host_addr;  /* 68-71 */
-  u16 ext_host_port;            /* 72-73 */
+  ip4_address_t ext_host_addr;
+  u16 ext_host_port;
 
   /* External host address and port after translation */
-  ip4_address_t ext_host_nat_addr; /* 74-77 */
-  u16 ext_host_nat_port;           /* 78-79 */
+  ip4_address_t ext_host_nat_addr;
+  u16 ext_host_nat_port;
 
   /* TCP session state */
   u8 state;
   u32 i2o_fin_seq;
   u32 o2i_fin_seq;
 }) snat_session_t;
+/* *INDENT-ON* */
 
 
-typedef struct {
+typedef struct
+{
   ip4_address_t addr;
   u32 fib_index;
   u32 sessions_per_user_list_head_index;
@@ -202,86 +227,131 @@ typedef struct {
   u32 nstaticsessions;
 } snat_user_t;
 
-typedef struct {
+typedef struct
+{
   ip4_address_t addr;
   u32 fib_index;
+/* *INDENT-OFF* */
 #define _(N, i, n, s) \
   u16 busy_##n##_ports; \
   u16 * busy_##n##_ports_per_thread; \
   uword * busy_##n##_port_bitmap;
   foreach_snat_protocol
 #undef _
+/* *INDENT-ON* */
 } snat_address_t;
 
-typedef struct {
+typedef struct
+{
   u32 fib_index;
   u32 refcount;
 } nat_outside_fib_t;
 
-typedef struct {
+typedef struct
+{
+  /* Inside network port */
   u16 in_port;
+  /* Outside network address and port */
   snat_det_out_key_t out;
+  /* Session state */
   u8 state;
+  /* Expire timeout */
   u32 expire;
 } snat_det_session_t;
 
-typedef struct {
+typedef struct
+{
+  /* inside IP address range */
   ip4_address_t in_addr;
   u8 in_plen;
+  /* outside IP address range */
   ip4_address_t out_addr;
   u8 out_plen;
+  /* inside IP addresses / outside IP addresses */
   u32 sharing_ratio;
+  /* number of ports available to internal host */
   u16 ports_per_host;
+  /* session counter */
   u32 ses_num;
   /* vector of sessions */
-  snat_det_session_t * sessions;
+  snat_det_session_t *sessions;
 } snat_det_map_t;
 
-typedef struct {
+typedef struct
+{
+  /* backend IP address */
   ip4_address_t addr;
+  /* backend port number */
   u16 port;
+  /* probability of the backend to be randomly matched */
   u8 probability;
   u8 prefix;
+  /* backend FIB table */
   u32 vrf_id;
   u32 fib_index;
 } nat44_lb_addr_port_t;
 
-typedef enum {
+typedef enum
+{
+  /* twice-nat disabled */
   TWICE_NAT_DISABLED,
+  /* twice-nat enabled */
   TWICE_NAT,
+  /* twice-nat only when src IP equals dst IP after translation */
   TWICE_NAT_SELF,
 } twice_nat_type_t;
 
-typedef enum {
+typedef enum
+{
+  /* no load-balancing */
   NO_LB_NAT,
+  /* load-balancing */
   LB_NAT,
+  /* load-balancing with affinity */
   AFFINITY_LB_NAT,
 } lb_nat_type_t;
 
-typedef struct {
+typedef struct
+{
+  /* local IP address */
   ip4_address_t local_addr;
+  /* external IP address */
   ip4_address_t external_addr;
+  /* local port */
   u16 local_port;
+  /* external port */
   u16 external_port;
+  /* 1 = 1:1NAT, 0 = 1:1NAPT */
   u8 addr_only;
+  /* is twice-nat */
   twice_nat_type_t twice_nat;
+  /* 1 = rule match only out2in direction */
   u8 out2in_only;
+  /* local FIB table */
   u32 vrf_id;
   u32 fib_index;
+  /* protocol */
   snat_protocol_t proto;
+  /* 0 = disabled, otherwise client IP affinity sticky time in seconds */
   u32 affinity;
+  /* worker threads used by backends/local host */
   u32 *workers;
+  /* opaque string tag */
   u8 *tag;
+  /* backends for load-balancing mode */
   nat44_lb_addr_port_t *locals;
+  /* affinity per service lis */
   u32 affinity_per_service_list_head_index;
 } snat_static_mapping_t;
 
-typedef struct {
+typedef struct
+{
   u32 sw_if_index;
   u8 flags;
 } snat_interface_t;
 
-typedef struct {
+typedef struct
+{
   ip4_address_t l_addr;
   u16 l_port;
   u16 e_port;
@@ -294,7 +364,8 @@ typedef struct {
   u8 *tag;
 } snat_static_map_resolve_t;
 
-typedef struct {
+typedef struct
+{
   /* Main lookup tables */
   clib_bihash_8_8_t out2in;
   clib_bihash_8_8_t in2out;
@@ -307,54 +378,60 @@ typedef struct {
   clib_bihash_8_8_t user_hash;
 
   /* User pool */
-  snat_user_t * users;
+  snat_user_t *users;
 
   /* Session pool */
-  snat_session_t * sessions;
+  snat_session_t *sessions;
 
   /* Pool of doubly-linked list elements */
-  dlist_elt_t * list_pool;
+  dlist_elt_t *list_pool;
 
+  /* NAT thread index */
   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;
-
+/* ICMP session match function */
+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);
+
+/* Return worker thread index for given packet */
+typedef u32 (snat_get_worker_function_t) (ip4_header_t * ip,
+					  u32 rx_fib_index);
+
+/* NAT address and port allacotaion function */
+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,
+						      u16 port_per_thread,
+						      u32 snat_thread_index);
+
+typedef struct snat_main_s
+{
+  /* ICMP session match functions */
+  snat_icmp_match_function_t *icmp_match_in2out_cb;
+  snat_icmp_match_function_t *icmp_match_out2in_cb;
+
+  /* Thread settings */
   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;
+  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;
+  snat_main_per_thread_data_t *per_thread_data;
 
   /* Find a static mapping by local */
   clib_bihash_8_8_t static_mapping_by_local;
@@ -363,14 +440,14 @@ typedef struct snat_main_s {
   clib_bihash_8_8_t static_mapping_by_external;
 
   /* Static mapping pool */
-  snat_static_mapping_t * static_mappings;
+  snat_static_mapping_t *static_mappings;
 
   /* Interface pool */
-  snat_interface_t * interfaces;
-  snat_interface_t * output_feature_interfaces;
+  snat_interface_t *interfaces;
+  snat_interface_t *output_feature_interfaces;
 
   /* Vector of outside addresses */
-  snat_address_t * addresses;
+  snat_address_t *addresses;
   /* Address and port allocation function */
   nat_alloc_out_addr_and_port_function_t *alloc_addr_and_port;
   /* Address and port allocation type */
@@ -384,14 +461,14 @@ typedef struct snat_main_s {
   u16 end_port;
 
   /* vector of outside fibs */
-  nat_outside_fib_t * outside_fibs;
+  nat_outside_fib_t *outside_fibs;
 
   /* Vector of twice NAT addresses for extenal hosts */
-  snat_address_t * twice_nat_addresses;
+  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;
+  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;
@@ -399,7 +476,7 @@ typedef struct snat_main_s {
   /* Randomize port allocation order */
   u32 random_seed;
 
-  /* Worker handoff index */
+  /* Worker handoff frame-queue index */
   u32 fq_in2out_index;
   u32 fq_in2out_output_index;
   u32 fq_out2in_index;
@@ -410,8 +487,8 @@ typedef struct snat_main_s {
   u32 out2in_node_index;
   u32 error_node_index;
 
-  /* Deterministic NAT */
-  snat_det_map_t * det_maps;
+  /* Deterministic NAT mappings */
+  snat_det_map_t *det_maps;
 
   /* If forwarding is enabled */
   u8 forwarding_enabled;
@@ -450,18 +527,25 @@ typedef struct snat_main_s {
   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;
+  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;
 
-typedef struct {
+typedef struct
+{
   u32 thread_index;
   f64 now;
 } nat44_is_idle_session_ctx_t;
 
+typedef struct
+{
+  u32 cached_sw_if_index;
+  u32 cached_ip4_address;
+} snat_runtime_t;
+
 extern snat_main_t snat_main;
 extern vlib_node_registration_t snat_in2out_node;
 extern vlib_node_registration_t snat_in2out_output_node;
@@ -484,42 +568,19 @@ 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);
-
-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,
-                               lb_nat_type_t *lb,
-                               ip4_address_t * ext_host_addr);
-
-void snat_add_del_addr_to_fib (ip4_address_t * addr,
-                               u8 p_len,
-                               u32 sw_if_index,
-                               int is_add);
-
+/* format functions */
 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;
+format_function_t format_snat_key;
+format_function_t format_static_mapping_key;
+format_function_t format_snat_protocol;
+format_function_t format_nat_addr_and_port_alloc_alg;
+format_function_t format_nat44_reass_trace;
+/* unformat functions */
+unformat_function_t unformat_snat_protocol;
 
 /** \brief Check if SNAT session is created from static mapping.
     @param s SNAT session
@@ -563,9 +624,25 @@ typedef struct {
 */
 #define is_affinity_sessions(s) (s->flags & SNAT_SESSION_FLAG_AFFINITY)
 
+/** \brief Check if NAT interface is inside.
+    @param i NAT interfce
+    @return 1 if inside interface
+*/
 #define nat_interface_is_inside(i) i->flags & NAT_INTERFACE_FLAG_IS_INSIDE
+
+/** \brief Check if NAT interface is outside.
+    @param i NAT interfce
+    @return 1 if outside interface
+*/
 #define nat_interface_is_outside(i) i->flags & NAT_INTERFACE_FLAG_IS_OUTSIDE
 
+/** \brief Check if NAT44 endpoint-dependent TCP session is closed.
+    @param s NAT session
+    @return 1 if session is closed
+*/
+#define nat44_is_ses_closed(s) s->state == 0xf
+
+/* logging */
 #define nat_log_err(...) \
   vlib_log(VLIB_LOG_LEVEL_ERR, snat_main.log_class, __VA_ARGS__)
 #define nat_log_warn(...) \
@@ -577,107 +654,402 @@ typedef struct {
 #define nat_log_debug(...)\
   vlib_log(VLIB_LOG_LEVEL_DEBUG, snat_main.log_class, __VA_ARGS__)
 
+/* ICMP session match functions */
+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_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);
+
+/* ICMP deterministic NAT session match functions */
+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_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);
+
+/* ICMP endpoint-dependent session match functions */
+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);
+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_in2out (snat_main_t * sm, vlib_buffer_t * b0, ip4_header_t * ip0,
+		 icmp46_header_t * icmp0, u32 sw_if_index0, u32 rx_fib_index0,
+		 vlib_node_runtime_t * node, u32 next0, u32 thread_index,
+		 void *d, void *e);
+
+u32 icmp_out2in (snat_main_t * sm, vlib_buffer_t * b0, ip4_header_t * ip0,
+		 icmp46_header_t * icmp0, u32 sw_if_index0, u32 rx_fib_index0,
+		 vlib_node_runtime_t * node, u32 next0, u32 thread_index,
+		 void *d, void *e);
+
+/* hairpinning functions */
+u32 snat_icmp_hairpinning (snat_main_t * sm, vlib_buffer_t * b0,
+			   ip4_header_t * ip0, icmp46_header_t * icmp0,
+			   int is_ed);
+void nat_hairpinning_sm_unknown_proto (snat_main_t * sm, vlib_buffer_t * b,
+				       ip4_header_t * ip);
+void nat44_ed_hairpinning_unknown_proto (snat_main_t * sm, vlib_buffer_t * b,
+					 ip4_header_t * ip);
+int snat_hairpinning (snat_main_t * sm, vlib_buffer_t * b0,
+		      ip4_header_t * ip0, udp_header_t * udp0,
+		      tcp_header_t * tcp0, u32 proto0, int is_ed);
+void nat44_reass_hairpinning (snat_main_t * sm, vlib_buffer_t * b0,
+			      ip4_header_t * ip0, u16 sport, u16 dport,
+			      u32 proto0, int is_ed);
+
+/* Call back functions for clib_bihash_add_or_overwrite_stale */
+int nat44_i2o_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg);
+int nat44_o2i_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg);
+int nat44_i2o_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg);
+int nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg);
+
+/**
+ * @brief Increment IPv4 address
+ */
+void increment_v4_address (ip4_address_t * a);
+
+/**
+ * @brief Add external address to NAT44 pool
+ *
+ * @param addr      IPv4 address
+ * @param vrf_id    VRF id of tenant, ~0 means independent of VRF
+ * @param twice_nat 1 if twice NAT address
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int snat_add_address (snat_main_t * sm, ip4_address_t * addr, u32 vrf_id,
+		      u8 twice_nat);
+
+/**
+ * @brief Delete external address from NAT44 pool
+ *
+ * @param addr      IPv4 address
+ * @param delete_sm 1 if delete static mapping using address
+ * @param twice_nat 1 if twice NAT address
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int snat_del_address (snat_main_t * sm, ip4_address_t addr, u8 delete_sm,
+		      u8 twice_nat);
+
+/**
+ * @brief Add/delete external address to FIB DPO (out2in DPO mode)
+ *
+ * @param addr   IPv4 address
+ * @param is_add 1 = add, 0 = delete
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+void nat44_add_del_address_dpo (ip4_address_t addr, u8 is_add);
+
+/**
+ * @brief Add/delete NAT44 static mapping
+ *
+ * @param l_addr      local IPv4 address
+ * @param e_addr      external IPv4 address
+ * @param l_port      local port number
+ * @param e_port      external port number
+ * @param vrf_id      local VRF ID
+ * @param addr_only   1 = 1:1NAT, 0 = 1:1NAPT
+ * @param sw_if_index use interface address as external IPv4 address
+ * @param proto       L4 protocol
+ * @param is_add      1 = add, 0 = delete
+ * @param twice_nat   twice-nat mode
+ * @param out2in_only if 1 rule match only out2in direction
+ * @param tagi        opaque string tag
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+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);
+
+/**
+ * @brief Add/delete static mapping with load-balancing (multiple backends)
+ *
+ * @param e_addr      external IPv4 address
+ * @param e_port      external port number
+ * @param proto       L4 protocol
+ * @param locals      list of local backends
+ * @param is_add      1 = add, 0 = delete
+ * @param twice_nat   twice-nat mode
+ * @param out2in_only if 1 rule match only out2in direction
+ * @param tag         opaque string tag
+ * @param affinity    0 = disabled, otherwise client IP affinity sticky time
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
+				     snat_protocol_t proto,
+				     nat44_lb_addr_port_t * locals, u8 is_add,
+				     twice_nat_type_t twice_nat,
+				     u8 out2in_only, u8 * tag, u32 affinity);
+
+clib_error_t *snat_api_init (vlib_main_t * vm, snat_main_t * sm);
+
+/**
+ * @brief Set NAT plugin workers
+ *
+ * @param bitmap NAT workers bitmap
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int snat_set_workers (uword * bitmap);
+
+/**
+ * @brief Enable/disable NAT44 feature on the interface
+ *
+ * @param sw_if_index software index of the interface
+ * @param is_inside   1 = inside, 0 = outside
+ * @param is_del      1 = delete, 0 = add
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int snat_interface_add_del (u32 sw_if_index, u8 is_inside, int is_del);
+
+/**
+ * @brief Enable/disable NAT44 output feature on the interface (postrouting NAT)
+ *
+ * @param sw_if_index software index of the interface
+ * @param is_inside   1 = inside, 0 = outside
+ * @param is_del      1 = delete, 0 = add
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int snat_interface_add_del_output_feature (u32 sw_if_index, u8 is_inside,
+					   int is_del);
+
+/**
+ * @brief Add/delete NAT44 pool address from specific interfce
+ *
+ * @param sw_if_index software index of the interface
+ * @param is_del      1 = delete, 0 = add
+ * @param twice_nat   1 = twice NAT address for extenal hosts
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int snat_add_interface_address (snat_main_t * sm, u32 sw_if_index, int is_del,
+				u8 twice_nat);
+
+/**
+ * @brief Delete NAT44 session
+ *
+ * @param addr   IPv4 address
+ * @param port   L4 port number
+ * @param proto  L4 protocol
+ * @param vrf_id VRF ID
+ * @param is_in  1 = inside network addres and por pair, 0 = outside
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int nat44_del_session (snat_main_t * sm, ip4_address_t * addr, u16 port,
+		       snat_protocol_t proto, u32 vrf_id, int is_in);
+
+/**
+ * @brief Delete NAT44 endpoint-dependent session
+ *
+ * @param addr   IPv4 address
+ * @param port   L4 port number
+ * @param proto  L4 protocol
+ * @param vrf_id VRF ID
+ * @param is_in  1 = inside network addres and por pair, 0 = outside
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+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);
+
+/**
+ * @brief Free NAT44 session data (lookup keys, external addrres port)
+ *
+ * @param s            NAT session
+ * @param thread_index thread index
+ */
+void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
+			    u32 thread_index);
+
+/**
+ * @brief Find or create NAT user
+ *
+ * @param addr         IPv4 address
+ * @param fib_index    FIB table index
+ * @param thread_index thread index
+ *
+ * @return NAT user data structure on success otherwise zero value
+ */
+snat_user_t *nat_user_get_or_create (snat_main_t * sm, ip4_address_t * addr,
+				     u32 fib_index, u32 thread_index);
+
+/**
+ * @brief Allocate new NAT session or recycle last used
+ *
+ * @param u            NAT user
+ * @param thread_index thread index
+ *
+ * @return session data structure on success otherwise zero value
+ */
+snat_session_t *nat_session_alloc_or_recycle (snat_main_t * sm,
+					      snat_user_t * u,
+					      u32 thread_index);
+
+/**
+ * @brief Allocate NAT endpoint-dependent session
+ *
+ * @param u            NAT user
+ * @param thread_index thread index
+ *
+ * @return session data structure on success otherwise zero value
+ */
+snat_session_t *nat_ed_session_alloc (snat_main_t * sm, snat_user_t * u,
+				      u32 thread_index);
+
+/**
+ * @brief Set address and port assignment algorithm for MAP-E CE
+ *
+ * @param psid        Port Set Identifier value
+ * @param psid_offset number of offset bits
+ * @param psid_length length of PSID
+ */
+void nat_set_alloc_addr_and_port_mape (u16 psid, u16 psid_offset,
+				       u16 psid_length);
+
+/**
+ * @brief Set address and port assignment algorithm for port range
+ *
+ * @param start_port beginning of the port range
+ * @param end_port   end of the port range
+ */
+void nat_set_alloc_addr_and_port_range (u16 start_port, u16 end_port);
+
+/**
+ * @brief Set address and port assignment algorithm to default/standard
+ */
+void nat_set_alloc_addr_and_port_default (void);
+
+/**
+ * @brief Free outside address and port pair
+ *
+ * @param addresses    vector of outside addresses
+ * @param thread_index thread index
+ * @param k            adddress, port and protocol
+ */
+void snat_free_outside_address_and_port (snat_address_t * addresses,
+					 u32 thread_index,
+					 snat_session_key_t * k);
+
+/**
+ * @brief Alloc outside address and port
+ *
+ * @param addresses         vector of outside addresses
+ * @param fib_index         FIB table index
+ * @param thread_index      thread index
+ * @param k                 allocated address and port pair
+ * @param port_per_thread   number of ports per threead
+ * @param snat_thread_index NAT thread index
+ *
+ * @return 0 on success, non-zero value otherwise
+ */
+int snat_alloc_outside_address_and_port (snat_address_t * addresses,
+					 u32 fib_index,
+					 u32 thread_index,
+					 snat_session_key_t * k,
+					 u16 port_per_thread,
+					 u32 snat_thread_index);
+
+/**
+ * @brief Match NAT44 static mapping.
+ *
+ * @param match         address and port to match
+ * @param mapping       external/local address and port of the matched mapping
+ * @param by_external   if 0 match by local address otherwise match by external
+ *                      address
+ * @param is_addr_only  1 if matched mapping is address only
+ * @param twice_nat     matched mapping is twice NAT type
+ * @param lb            1 if matched mapping is load-balanced
+ * @param ext_host_addr external host address
+ *
+ * @returns 0 if match found otherwise 1.
+ */
+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,
+			       lb_nat_type_t * lb,
+			       ip4_address_t * ext_host_addr);
+
+/**
+ * @brief Add/del NAT address to FIB.
+ *
+ * Add the external NAT address to the FIB as receive entries. This ensures
+ * that VPP will reply to ARP for this address and we don't need to enable
+ * proxy ARP on the outside interface.
+ *
+ * @param addr        IPv4 address
+ * @param plen        address prefix length
+ * @param sw_if_index software index of the outside interface
+ * @param is_add      0 = delete, 1 = add.
+ */
+void snat_add_del_addr_to_fib (ip4_address_t * addr,
+			       u8 p_len, u32 sw_if_index, int is_add);
+
+
 /*
  * 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 {
+typedef struct
+{
   u16 identifier;
   u16 sequence;
 } icmp_echo_header_t;
 
-typedef struct {
+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);
-u8 * format_nat_addr_and_port_alloc_alg(u8 * s, va_list * args);
-int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
-                                     snat_protocol_t proto,
-                                     nat44_lb_addr_port_t *locals, u8 is_add,
-                                     twice_nat_type_t twice_nat, u8 out2in_only,
-                                     u8 *tag, u32 affinity);
-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);
-snat_session_t * nat_ed_session_alloc (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_range (u16 start_port, u16 end_port);
-void nat_set_alloc_addr_and_port_default (void);
-int nat44_i2o_ed_is_idle_session_cb (clib_bihash_kv_16_8_t *kv, void *arg);
-int nat44_o2i_ed_is_idle_session_cb (clib_bihash_kv_16_8_t *kv, void *arg);
-int nat44_i2o_is_idle_session_cb (clib_bihash_kv_8_8_t *kv, void *arg);
-int nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t *kv, void *arg);
+#endif /* __included_nat_h__ */
 
-#endif /* __included_snat_h__ */
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */