diff --git a/src/id_generator/id_generator.cpp b/src/id_generator/id_generator.cpp
index d66bd45..8cc68ab 100644
--- a/src/id_generator/id_generator.cpp
+++ b/src/id_generator/id_generator.cpp
@@ -1,11 +1,15 @@
 #include <time.h>
 #include <string.h>
 
+#include "log.h"
 #include "macro.h"
 #include "times.h"
-#include "stellar_priv.h"
+#include "stellar_utils.h"
 #include "id_generator.h"
 
+#define ID_GENERATOR_LOG_ERROR(format, ...) LOG_ERROR("id generator", format, ##__VA_ARGS__)
+#define ID_GENERATOR_LOG_DEBUG(format, ...) LOG_DEBUG("id generator", format, ##__VA_ARGS__)
+
 struct id_generator
 {
     uint8_t device_base;   // 5bit  [0, 31]
diff --git a/src/id_generator/id_generator.h b/src/id_generator/id_generator.h
index c100264..1f356ef 100644
--- a/src/id_generator/id_generator.h
+++ b/src/id_generator/id_generator.h
@@ -7,11 +7,6 @@ extern "C"
 
 #include <stdint.h>
 
-#include "log.h"
-
-#define ID_GENERATOR_LOG_ERROR(format, ...) LOG_ERROR("id generator", format, ##__VA_ARGS__)
-#define ID_GENERATOR_LOG_DEBUG(format, ...) LOG_DEBUG("id generator", format, ##__VA_ARGS__)
-
 /*
  * device_base   (5bit)  : [0, 31]
  * device_offset (7bit)  : [0, 127]
diff --git a/src/packet/packet_def.h b/src/packet/packet_def.h
index 3e24343..7cb8deb 100644
--- a/src/packet/packet_def.h
+++ b/src/packet/packet_def.h
@@ -23,7 +23,7 @@ struct metadata
     struct sids sids;
 
     uint64_t session_id;
-    uint64_t domain_id;
+    uint64_t domain;
     uint16_t link_id;
     int is_ctrl;
 
diff --git a/src/packet/packet_utils.cpp b/src/packet/packet_utils.cpp
index 6b249f8..5a07136 100644
--- a/src/packet/packet_utils.cpp
+++ b/src/packet/packet_utils.cpp
@@ -66,14 +66,14 @@ uint64_t packet_get_session_id(const struct packet *pkt)
     return pkt->meta.session_id;
 }
 
-void packet_set_domain_id(struct packet *pkt, uint64_t id)
+void packet_set_domain(struct packet *pkt, uint64_t domain)
 {
-    pkt->meta.domain_id = id;
+    pkt->meta.domain = domain;
 }
 
-uint64_t packet_get_domain_id(const struct packet *pkt)
+uint64_t packet_get_domain(const struct packet *pkt)
 {
-    return pkt->meta.domain_id;
+    return pkt->meta.domain;
 }
 
 void packet_set_link_id(struct packet *pkt, uint16_t id)
@@ -326,7 +326,6 @@ int packet_get_innermost_tuple6(const struct packet *pkt, struct tuple6 *tuple)
     const struct raw_layer *layer_l3 = NULL;
     const struct raw_layer *layer_l4 = NULL;
     const struct raw_layer *layer = NULL;
-    uint64_t domain = packet_get_domain_id(pkt);
 
     for (int8_t i = pkt->layers_used - 1; i >= 0; i--)
     {
@@ -375,7 +374,7 @@ int packet_get_innermost_tuple6(const struct packet *pkt, struct tuple6 *tuple)
 
     if (layer_l3 && layer_l4 && layer_l4 - layer_l3 == 1)
     {
-        tuple->domain = packet_get_domain_id(pkt);
+        tuple->domain = packet_get_domain(pkt);
         return 0;
     }
     else
@@ -392,7 +391,6 @@ int packet_get_outermost_tuple6(const struct packet *pkt, struct tuple6 *tuple)
     const struct raw_layer *layer_l3 = NULL;
     const struct raw_layer *layer_l4 = NULL;
     const struct raw_layer *layer = NULL;
-    uint64_t domain = packet_get_domain_id(pkt);
 
     for (int8_t i = 0; i < pkt->layers_used; i++)
     {
@@ -441,7 +439,7 @@ int packet_get_outermost_tuple6(const struct packet *pkt, struct tuple6 *tuple)
 
     if (layer_l3 && layer_l4 && layer_l4 - layer_l3 == 1)
     {
-        tuple->domain = packet_get_domain_id(pkt);
+        tuple->domain = packet_get_domain(pkt);
         return 0;
     }
     else
diff --git a/src/packet/packet_utils.h b/src/packet/packet_utils.h
index 3e4c4f9..fb8d3e7 100644
--- a/src/packet/packet_utils.h
+++ b/src/packet/packet_utils.h
@@ -22,8 +22,8 @@ void packet_prepend_sids(struct packet *pkt, const struct sids *sids);
 void packet_set_session_id(struct packet *pkt, uint64_t id);
 uint64_t packet_get_session_id(const struct packet *pkt);
 
-void packet_set_domain_id(struct packet *pkt, uint64_t id);
-uint64_t packet_get_domain_id(const struct packet *pkt);
+void packet_set_domain(struct packet *pkt, uint64_t domain);
+uint64_t packet_get_domain(const struct packet *pkt);
 
 void packet_set_link_id(struct packet *pkt, uint16_t id);
 uint16_t packet_get_link_id(const struct packet *pkt);
diff --git a/src/packet_io/lock_free_queue.cpp b/src/packet_io/lock_free_queue.cpp
index a8d03e2..17d1b65 100644
--- a/src/packet_io/lock_free_queue.cpp
+++ b/src/packet_io/lock_free_queue.cpp
@@ -3,9 +3,13 @@
 #include <unistd.h>
 #include <stdint.h>
 
+#include "log.h"
 #include "macro.h"
 #include "lock_free_queue.h"
 
+#define LOCK_FREE_QUEUE_LOG_ERROR(format, ...) LOG_ERROR("lock free queue", format, ##__VA_ARGS__)
+#define LOCK_FREE_QUEUE_LOG_DEBUG(format, ...) LOG_DEBUG("lock free queue", format, ##__VA_ARGS__)
+
 struct lock_free_queue
 {
     uint64_t *queue;
diff --git a/src/packet_io/lock_free_queue.h b/src/packet_io/lock_free_queue.h
index 584f561..7acbc62 100644
--- a/src/packet_io/lock_free_queue.h
+++ b/src/packet_io/lock_free_queue.h
@@ -5,11 +5,6 @@ extern "C"
 {
 #endif
 
-#include "log.h"
-
-#define LOCK_FREE_QUEUE_LOG_ERROR(format, ...) LOG_ERROR("lock free queue", format, ##__VA_ARGS__)
-#define LOCK_FREE_QUEUE_LOG_DEBUG(format, ...) LOG_DEBUG("lock free queue", format, ##__VA_ARGS__)
-
 struct lock_free_queue;
 
 struct lock_free_queue *lock_free_queue_new(uint32_t size);
diff --git a/src/packet_io/marsio_io.cpp b/src/packet_io/marsio_io.cpp
index 7add76b..2850d6d 100644
--- a/src/packet_io/marsio_io.cpp
+++ b/src/packet_io/marsio_io.cpp
@@ -31,7 +31,7 @@ static void metadata_from_mbuff_to_packet(marsio_buff_t *mbuff, struct packet *p
     struct route_ctx route_ctx = {0};
     struct sids sids = {0};
     uint64_t session_id = {0};
-    uint64_t domain_id = {0};
+    uint64_t domain = {0};
     uint16_t link_id = {0};
     int is_ctrl = {0};
     enum packet_direction direction = PACKET_DIRECTION_OUTGOING;
@@ -67,9 +67,9 @@ static void metadata_from_mbuff_to_packet(marsio_buff_t *mbuff, struct packet *p
 
 // TODO
 #if 0
-    if (marsio_buff_get_metadata(mbuff, MR_BUFF_DOMAIN_ID, &domain_id, sizeof(domain_id)) == sizeof(domain_id))
+    if (marsio_buff_get_metadata(mbuff, MR_BUFF_DOMAIN, &domain, sizeof(domain)) == sizeof(domain))
     {
-        packet_set_domain_id(pkt, domain_id);
+        packet_set_domain(pkt, domain);
     }
     else
     {
@@ -107,7 +107,7 @@ static void metadata_from_packet_to_mbuff(struct packet *pkt, marsio_buff_t *mbu
     const struct route_ctx *route_ctx = packet_get_route_ctx(pkt);
     const struct sids *sids = packet_get_sids(pkt);
     uint64_t session_id = packet_get_session_id(pkt);
-    uint64_t domain_id = packet_get_domain_id(pkt);
+    uint64_t domain = packet_get_domain(pkt);
     uint16_t link_id = packet_get_link_id(pkt);
     int is_ctrl = packet_is_ctrl(pkt);
     enum packet_direction direction = packet_get_direction(pkt);
@@ -129,7 +129,7 @@ static void metadata_from_packet_to_mbuff(struct packet *pkt, marsio_buff_t *mbu
 
 // TODO
 #if 0
-    if (marsio_buff_set_metadata(mbuff, MR_BUFF_DOMAIN_ID, &domain_id, sizeof(domain_id)) != 0)
+    if (marsio_buff_set_metadata(mbuff, MR_BUFF_DOMAIN, &domain, sizeof(domain)) != 0)
     {
         PACKET_IO_LOG_ERROR("failed to set domain id");
     }
diff --git a/src/plugin/plugin_manager.cpp b/src/plugin/plugin_manager.cpp
index 2dfa3cc..2d0cd1d 100644
--- a/src/plugin/plugin_manager.cpp
+++ b/src/plugin/plugin_manager.cpp
@@ -1,9 +1,9 @@
 #include <assert.h>
 #include "plugin_manager.h"
-#include "session_priv.h"
-#include "stellar_priv.h"
+#include "session_utils.h"
+#include "packet_utils.h"
+#include "stellar_utils.h"
 #include "stellar/utils.h"
-#include "stellar/session.h"
 #include "stellar/session_exdata.h"
 #include "stellar/session_mq.h"
 #include "tcp_reassembly.h"
@@ -212,7 +212,6 @@ PLUGIN_SPEC_LOAD_ERROR:
 	return NULL;	
 }
 
-#include "session_priv.h"
 static void tcp_stream_msg_free_fn(void *msg, void *msg_free_arg)
 {
 	struct session *cur_sess = plugin_manager_scratch_session_get();
diff --git a/src/plugin/plugin_manager.h b/src/plugin/plugin_manager.h
index b6dd98f..236a1ff 100644
--- a/src/plugin/plugin_manager.h
+++ b/src/plugin/plugin_manager.h
@@ -5,11 +5,6 @@ extern "C"
 {
 #endif
 
-#include "session_priv.h"
-
-#define PLUGIN_MANAGER_LOG_ERROR(format, ...) LOG_ERROR("plugin manager", format, ##__VA_ARGS__)
-#define PLUGIN_MANAGER_LOG_DEBUG(format, ...) LOG_DEBUG("plugin manager", format, ##__VA_ARGS__)
-
 struct plugin_manager_schema;
 struct plugin_manager_runtime;
 
diff --git a/src/session/CMakeLists.txt b/src/session/CMakeLists.txt
index e7c2d0d..1573f66 100644
--- a/src/session/CMakeLists.txt
+++ b/src/session/CMakeLists.txt
@@ -1,5 +1,5 @@
 add_library(session_manager
-    session.cpp
+    session_utils.cpp
     session_pool.cpp
     session_table.cpp
     session_timer.cpp
diff --git a/src/session/session_def.h b/src/session/session_def.h
new file mode 100644
index 0000000..a611f18
--- /dev/null
+++ b/src/session/session_def.h
@@ -0,0 +1,83 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include "list.h"
+#include "tuple.h"
+#include "uthash.h"
+#include "timeout.h"
+#include "packet_def.h"
+#include "stellar/session.h"
+#include "tcp_reassembly.h"
+
+#define EX_DATA_MAX_COUNT 4
+
+// output format: "${src_addr}:${src_port}-${dst_addr}:${dst_port}-${ip_proto}-${domain}"
+// output max len: (46 + 1 + 5) + 1 + (46 + 1 + 5) + 1 + 1 + 1 + 20 = 129
+#define TUPLE6_STR_SIZE 130
+
+struct tcp_half
+{
+    struct tcp_reassembly *assembler;
+    struct tcp_segment in_order; // current packet in order segment
+    uint32_t in_order_ref;       // reference count of current packet in order segment
+
+    uint32_t inject_inc_seq_offset; // inject packet base on current packet increase seq offset
+    uint32_t inject_inc_ack_offset; // inject packet base on current packet increase ack offset
+
+    uint32_t seq;  // current packet sequence number
+    uint32_t ack;  // current packet ack number
+    uint16_t len;  // current packet payload length
+    uint8_t flags; // current packet flags
+
+    uint32_t isn;    // current direction initial sequence number
+    uint8_t history; // current direction received flags
+};
+
+/*
+ * sizeof(struct session) > 1024 bytes
+ * max thread number = 128
+ * per thread max tcp session number = 50000
+ * per thread max udp session number = 50000
+ *
+ * session memory usage = 128 * (50000 + 50000) * 1024 = 13107200000 bytes = 12.2 GB
+ */
+struct session
+{
+    uint64_t id;
+    uint64_t stats[MAX_FLOW_DIRECTION][MAX_STAT];
+    uint64_t timestamps[MAX_TIMESTAMP]; // realtime seconds
+    struct tcp_half tcp_halfs[MAX_FLOW_DIRECTION];
+    struct timeout timeout;
+    struct list_head lru;
+    struct list_head free;
+    struct list_head evicte;
+    UT_hash_handle hh1;
+    UT_hash_handle hh2;
+    UT_hash_handle hh3;
+    struct tuple6 tuple;
+    char tuple_str[TUPLE6_STR_SIZE];
+    struct sids sids[MAX_FLOW_DIRECTION];
+    struct route_ctx route_ctx[MAX_FLOW_DIRECTION];
+    const struct packet *first_pkt[MAX_FLOW_DIRECTION];
+    const struct packet *curr_pkt;
+    void *ex_data[EX_DATA_MAX_COUNT];
+    void *user_data;
+    int is_symmetric;
+    int dup;
+    enum session_direction sess_dir;
+    enum flow_direction tuple_dir;
+    enum flow_direction flow_dir;
+    enum session_type type;
+    enum session_state state;
+    enum closing_reason reason;
+    struct session_manager *mgr;
+    struct session_manager_stat *mgr_stat;
+};
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/session/session_manager.cpp b/src/session/session_manager.cpp
index 1ccd9ec..d9dd5e5 100644
--- a/src/session/session_manager.cpp
+++ b/src/session/session_manager.cpp
@@ -2,12 +2,16 @@
 #include <stdlib.h>
 #include <assert.h>
 
+#include "log.h"
 #include "macro.h"
 #include "times.h"
 #include "tcp_utils.h"
 #include "udp_utils.h"
 #include "packet_layer.h"
+#include "packet_utils.h"
 #include "id_generator.h"
+#include "session_def.h"
+#include "session_utils.h"
 #include "session_pool.h"
 #include "session_table.h"
 #include "session_timer.h"
@@ -16,6 +20,9 @@
 #include "evicted_session_filter.h"
 #include "duplicated_packet_filter.h"
 
+#define SESSION_LOG_ERROR(format, ...) LOG_ERROR("session", format, ##__VA_ARGS__)
+#define SESSION_LOG_DEBUG(format, ...) LOG_DEBUG("session", format, ##__VA_ARGS__)
+
 struct session_manager
 {
      struct list_head evicte_queue;
@@ -528,7 +535,7 @@ static void session_update(struct session *sess, enum session_state next_state,
      if (session_get_current_state(sess) == SESSION_STATE_INIT)
      {
           session_set_id(sess, id_generator_alloc());
-          session_set_tuple(sess, key);
+          session_set_tuple6(sess, key);
           session_set_tuple_direction(sess, dir);
 
           enum packet_direction pkt_dir = packet_get_direction(pkt);
diff --git a/src/session/session_manager.h b/src/session/session_manager.h
index 48cf685..f562a80 100644
--- a/src/session/session_manager.h
+++ b/src/session/session_manager.h
@@ -5,12 +5,6 @@ extern "C"
 {
 #endif
 
-#include "session_priv.h"
-#include "log.h"
-
-#define SESSION_LOG_ERROR(format, ...) LOG_ERROR("session", format, ##__VA_ARGS__)
-#define SESSION_LOG_DEBUG(format, ...) LOG_DEBUG("session", format, ##__VA_ARGS__)
-
 struct session_manager_options
 {
     // max session number
diff --git a/src/session/session_pool.cpp b/src/session/session_pool.cpp
index 134a752..aff982a 100644
--- a/src/session/session_pool.cpp
+++ b/src/session/session_pool.cpp
@@ -1,3 +1,6 @@
+#include <stdlib.h>
+
+#include "session_def.h"
 #include "session_pool.h"
 
 struct session_pool
diff --git a/src/session/session_pool.h b/src/session/session_pool.h
index 76433a5..49d035c 100644
--- a/src/session/session_pool.h
+++ b/src/session/session_pool.h
@@ -5,7 +5,7 @@ extern "C"
 {
 #endif
 
-#include "session_priv.h"
+#include <stdint.h>
 
 struct session_pool;
 struct session_pool *session_pool_new(uint64_t count);
diff --git a/src/session/session_table.cpp b/src/session/session_table.cpp
index bd62db7..24d735a 100644
--- a/src/session/session_table.cpp
+++ b/src/session/session_table.cpp
@@ -2,6 +2,7 @@
 
 #define HASH_FUNCTION(keyptr, keylen, hashv) HASH_FUNCTION_OVERWRITE(keyptr, keylen, &hashv)
 #define HASH_KEYCMP(a, b, len) HASH_KEYCMP_OVERWRITE(a, b, len)
+#include "session_def.h"
 #include "session_table.h"
 
 struct session_table
diff --git a/src/session/session_table.h b/src/session/session_table.h
index d543543..205f3e0 100644
--- a/src/session/session_table.h
+++ b/src/session/session_table.h
@@ -5,8 +5,6 @@ extern "C"
 {
 #endif
 
-#include "session_priv.h"
-
 struct session_table;
 struct session_table *session_table_new();
 void session_table_free(struct session_table *table);
diff --git a/src/session/session_timer.cpp b/src/session/session_timer.cpp
index 07cb3bc..c3ff593 100644
--- a/src/session/session_timer.cpp
+++ b/src/session/session_timer.cpp
@@ -1,3 +1,4 @@
+#include "session_def.h"
 #include "session_timer.h"
 
 struct session_timer
diff --git a/src/session/session_timer.h b/src/session/session_timer.h
index 074522a..56b2f79 100644
--- a/src/session/session_timer.h
+++ b/src/session/session_timer.h
@@ -5,7 +5,7 @@ extern "C"
 {
 #endif
 
-#include "session_priv.h"
+#include <stdint.h>
 
 struct session_timer;
 struct session_timer *session_timer_new(uint64_t now);
diff --git a/src/session/session_transition.cpp b/src/session/session_transition.cpp
index 5a61d0a..cd439eb 100644
--- a/src/session/session_transition.cpp
+++ b/src/session/session_transition.cpp
@@ -1,8 +1,12 @@
 #include <stdio.h>
 #include <assert.h>
 
+#include "log.h"
+#include "session_utils.h"
 #include "session_transition.h"
 
+#define SESSION_TRANSITION_LOG_INFO(format, ...) LOG_INFO("session transition", format, ##__VA_ARGS__)
+
 #define MAX_TRANSITION_PER_STATE 8
 
 struct session_transition
diff --git a/src/session/session_transition.h b/src/session/session_transition.h
index a23031d..e413f93 100644
--- a/src/session/session_transition.h
+++ b/src/session/session_transition.h
@@ -5,10 +5,7 @@ extern "C"
 {
 #endif
 
-#include "log.h"
-#include "session_priv.h"
-
-#define SESSION_TRANSITION_LOG_INFO(format, ...) LOG_INFO("session transition", format, ##__VA_ARGS__)
+#include "stellar/session.h"
 
 enum session_inputs
 {
diff --git a/src/session/session.cpp b/src/session/session_utils.cpp
similarity index 97%
rename from src/session/session.cpp
rename to src/session/session_utils.cpp
index cb90fee..6d4c007 100644
--- a/src/session/session.cpp
+++ b/src/session/session_utils.cpp
@@ -1,26 +1,25 @@
 #include <assert.h>
 
-#include "packet_def.h"
-#include "session_priv.h"
-#include "tcp_utils.h"
-#include "tcp_reassembly.h"
+#include "session_def.h"
+#include "session_utils.h"
+#include "session_manager.h"
 
 #define EX_KEY_MAX_LEN 64
 
-struct ex_schema
+struct session_exdata_schema
 {
     char key[EX_KEY_MAX_LEN];
     session_ex_free_cb *free_cb;
     void *args;
 };
 
-struct ex_manager
+struct session_exdata_manager
 {
-    struct ex_schema schemas[EX_DATA_MAX_COUNT];
+    struct session_exdata_schema schemas[EX_DATA_MAX_COUNT];
     uint8_t count;
 };
 
-static struct ex_manager g_ex_manager = {0};
+static struct session_exdata_manager g_ex_manager = {0};
 
 /******************************************************************************
  * session set/get
@@ -41,7 +40,7 @@ uint64_t session_get_id(const struct session *sess)
     return sess->id;
 }
 
-void session_set_tuple(struct session *sess, const struct tuple6 *tuple)
+void session_set_tuple6(struct session *sess, const struct tuple6 *tuple)
 {
     memcpy(&sess->tuple, tuple, sizeof(struct tuple6));
 }
@@ -264,6 +263,7 @@ struct tcp_segment *session_get_tcp_segment(struct session *sess)
             session_inc_stat(sess, dir, STAT_TCP_SEGMENTS_REORDERED, 1);
             session_inc_stat(sess, dir, STAT_TCP_PAYLOADS_REORDERED, seg->len);
 
+            // TODO
             sess->mgr_stat->nr_tcp_seg_reorded++;
         }
         return seg;
@@ -326,7 +326,7 @@ uint8_t session_get_ex_new_index(const char *key, session_ex_free_cb *free_cb, v
     uint8_t idx = g_ex_manager.count;
     g_ex_manager.count++;
 
-    struct ex_schema *schema = &g_ex_manager.schemas[idx];
+    struct session_exdata_schema *schema = &g_ex_manager.schemas[idx];
     strncpy(schema->key, key, EX_KEY_MAX_LEN);
     schema->free_cb = free_cb;
     schema->args = args;
@@ -377,7 +377,7 @@ void session_free_ex_data(struct session *sess, uint8_t idx)
         return;
     }
 
-    struct ex_schema *schema = &g_ex_manager.schemas[idx];
+    struct session_exdata_schema *schema = &g_ex_manager.schemas[idx];
     if (schema->free_cb != NULL && sess->ex_data[idx] != NULL)
     {
         printf("free ex_data, idx: %d, key: %s, val: %p\n", idx, schema->key, sess->ex_data[idx]);
diff --git a/src/session/session_priv.h b/src/session/session_utils.h
similarity index 61%
rename from src/session/session_priv.h
rename to src/session/session_utils.h
index c53fbeb..cd2811c 100644
--- a/src/session/session_priv.h
+++ b/src/session/session_utils.h
@@ -5,113 +5,88 @@ extern "C"
 {
 #endif
 
-#include "list.h"
-#include "tuple.h"
-#include "uthash.h"
-#include "timeout.h"
-#include "packet_def.h"
-#include "packet_utils.h"
+#include <stdint.h>
+
 #include "stellar/session.h"
-#include "tcp_reassembly.h"
-#include "session_manager.h"
 
-#define EX_DATA_MAX_COUNT 4
-
-// output format: "${src_addr}:${src_port}-${dst_addr}:${dst_port}-${ip_proto}-${domain}"
-// output max len: (46 + 1 + 5) + 1 + (46 + 1 + 5) + 1 + 1 + 1 + 20 = 129
-#define TUPLE6_STR_SIZE 130
-
-struct tcp_half
-{
-    struct tcp_reassembly *assembler;
-    struct tcp_segment in_order; // current packet in order segment
-    uint32_t in_order_ref;       // reference count of current packet in order segment
-
-    uint32_t inject_inc_seq_offset; // inject packet base on current packet increase seq offset
-    uint32_t inject_inc_ack_offset; // inject packet base on current packet increase ack offset
-
-    uint32_t seq;  // current packet sequence number
-    uint32_t ack;  // current packet ack number
-    uint16_t len;  // current packet payload length
-    uint8_t flags; // current packet flags
-
-    uint32_t isn;    // current direction initial sequence number
-    uint8_t history; // current direction received flags
-};
-
-/*
- * sizeof(struct session) > 1024 bytes
- * max thread number = 128
- * per thread max tcp session number = 50000
- * per thread max udp session number = 50000
- *
- * session memory usage = 128 * (50000 + 50000) * 1024 = 13107200000 bytes = 12.2 GB
- */
-struct session
-{
-    uint64_t id;
-    uint64_t stats[MAX_FLOW_DIRECTION][MAX_STAT];
-    uint64_t timestamps[MAX_TIMESTAMP]; // realtime seconds
-    struct tcp_half tcp_halfs[MAX_FLOW_DIRECTION];
-    struct timeout timeout;
-    struct list_head lru;
-    struct list_head free;
-    struct list_head evicte;
-    UT_hash_handle hh1;
-    UT_hash_handle hh2;
-    UT_hash_handle hh3;
-    struct tuple6 tuple;
-    char tuple_str[TUPLE6_STR_SIZE];
-    struct sids sids[MAX_FLOW_DIRECTION];
-    struct route_ctx route_ctx[MAX_FLOW_DIRECTION];
-    const struct packet *first_pkt[MAX_FLOW_DIRECTION];
-    const struct packet *curr_pkt;
-    void *ex_data[EX_DATA_MAX_COUNT];
-    void *user_data;
-    int is_symmetric;
-    int dup;
-    enum session_direction sess_dir;
-    enum flow_direction tuple_dir;
-    enum flow_direction flow_dir;
-    enum session_type type;
-    enum session_state state;
-    enum closing_reason reason;
-    struct session_manager *mgr;
-    struct session_manager_stat *mgr_stat;
-};
+/******************************************************************************
+ * session set/get
+ ******************************************************************************/
 
 void session_init(struct session *sess);
-void session_set_id(struct session *sess, uint64_t id);
 
-void session_set_tuple(struct session *sess, const struct tuple6 *key);
+// session ID
+void session_set_id(struct session *sess, uint64_t id);
+uint64_t session_get_id(const struct session *sess);
+
+// session tuple
+void session_set_tuple6(struct session *sess, const struct tuple6 *tuple);
 const struct tuple6 *session_get_tuple6(const struct session *sess);
 
+// session tuple direction
 void session_set_tuple_direction(struct session *sess, enum flow_direction dir);
 enum flow_direction session_get_tuple6_direction(const struct session *sess);
+const char *session_get0_readable_addr(const struct session *sess);
 
+// session direction
 void session_set_direction(struct session *sess, enum session_direction dir);
-void session_set_current_flow_direction(struct session *sess, enum flow_direction dir);
-void session_set_current_state(struct session *sess, enum session_state state);
-void session_set_type(struct session *sess, enum session_type type);
-void session_set_duplicate_traffic(struct session *sess);
-void session_set_closing_reason(struct session *sess, enum closing_reason reason);
-void session_inc_stat(struct session *sess, enum flow_direction dir, enum session_stat stat, uint64_t val);
-void session_set_timestamp(struct session *sess, enum session_timestamp type, uint64_t value);
+enum session_direction session_get_direction(const struct session *sess);
 
+// session flow direction
+void session_set_current_flow_direction(struct session *sess, enum flow_direction dir);
+enum flow_direction session_get_current_flow_direction(const struct session *sess);
+
+// session state
+void session_set_current_state(struct session *sess, enum session_state state);
+enum session_state session_get_current_state(const struct session *sess);
+
+// session type
+void session_set_type(struct session *sess, enum session_type type);
+enum session_type session_get_type(const struct session *sess);
+
+// session seen duplicate traffic
+void session_set_duplicate_traffic(struct session *sess);
+int session_has_duplicate_traffic(const struct session *sess);
+
+// session closing reason
+void session_set_closing_reason(struct session *sess, enum closing_reason reason);
+enum closing_reason session_get_closing_reason(const struct session *sess);
+
+// session stat
+void session_inc_stat(struct session *sess, enum flow_direction dir, enum session_stat stat, uint64_t val);
+uint64_t session_get_stat(const struct session *sess, enum flow_direction dir, enum session_stat stat);
+
+// session timestamp
+void session_set_timestamp(struct session *sess, enum session_timestamp type, uint64_t value);
+uint64_t session_get_timestamp(const struct session *sess, enum session_timestamp type);
+
+// session sids
 void session_clear_sids(struct session *sess, enum flow_direction dir);
 void session_set_sids(struct session *sess, enum flow_direction dir, const struct sids *sids);
 const struct sids *session_get_sids(const struct session *sess, enum flow_direction dir);
 
+// session route ctx
 void session_clear_route_ctx(struct session *sess, enum flow_direction dir);
 void session_set_route_ctx(struct session *sess, enum flow_direction dir, const struct route_ctx *ctx);
 const struct route_ctx *session_get_route_ctx(const struct session *sess, enum flow_direction dir);
 
+// session first packet
 void session_set_first_packet(struct session *sess, enum flow_direction dir, const struct packet *pkt);
-void session_set_current_packet(struct session *sess, const struct packet *pkt);
+const struct packet *session_get_first_packet(const struct session *sess, enum flow_direction dir);
 
+// session current packet
+void session_set_current_packet(struct session *sess, const struct packet *pkt);
+const struct packet *session_get0_current_packet(const struct session *sess);
+const char *session_get0_current_payload(const struct session *sess, uint16_t *payload_len);
+
+// session symmetric
+int session_is_symmetric(const struct session *sess, unsigned char *flag);
+
+// session user data
 void session_set_user_data(struct session *sess, void *user_data);
 void *session_get_user_data(const struct session *sess);
 
+// session tcp segment
 struct tcp_segment *session_get_tcp_segment(struct session *sess);
 void session_free_tcp_segment(struct session *sess, struct tcp_segment *seg);
 
@@ -129,6 +104,7 @@ typedef void session_ex_free_cb(struct session *sess, uint8_t idx, void *ex_ptr,
  * if key exist, not allow update, return original index.
  */
 uint8_t session_get_ex_new_index(const char *key, session_ex_free_cb *free_cb, void *args);
+
 /*
  * Support update ex_data.
  *
@@ -147,15 +123,16 @@ void session_free_ex_data(struct session *sess, uint8_t idx);
 void session_free_all_ex_data(struct session *sess);
 
 /******************************************************************************
- * debug
+ * to string
  ******************************************************************************/
 
-const char *session_type_to_str(enum session_type type);
-const char *session_state_to_str(enum session_state state);
-const char *flow_direction_to_str(enum flow_direction dir);
 const char *closing_reason_to_str(enum closing_reason reason);
-void session_print(struct session *sess);
+const char *session_state_to_str(enum session_state state);
+const char *session_type_to_str(enum session_type type);
+const char *flow_direction_to_str(enum flow_direction dir);
+
 int session_to_json(struct session *sess, char *buff, int size);
+void session_print(struct session *sess);
 
 #ifdef __cplusplus
 }
diff --git a/src/session/test/gtest_case_tcp_fast_open.cpp b/src/session/test/gtest_case_tcp_fast_open.cpp
index 5af9e20..26329a2 100644
--- a/src/session/test/gtest_case_tcp_fast_open.cpp
+++ b/src/session/test/gtest_case_tcp_fast_open.cpp
@@ -1,9 +1,12 @@
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
+#include "packet_def.h"
 #include "packet_parse.h"
-#include "session_priv.h"
+#include "session_utils.h"
 #include "session_manager.h"
+#include "tcp_reassembly.h"
 
 struct session_manager_options opts = {
     // max session number
diff --git a/src/session/test/gtest_filter_tcp_dupkt.cpp b/src/session/test/gtest_filter_tcp_dupkt.cpp
index b16c3a6..e0d30bb 100644
--- a/src/session/test/gtest_filter_tcp_dupkt.cpp
+++ b/src/session/test/gtest_filter_tcp_dupkt.cpp
@@ -1,9 +1,11 @@
 #include <gtest/gtest.h>
 
-#include "session_priv.h"
-#include "session_manager.h"
-
 #include "ipv4_utils.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
+#include "session_manager.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_overload_evict_tcp_sess.cpp b/src/session/test/gtest_overload_evict_tcp_sess.cpp
index 942b803..421f189 100644
--- a/src/session/test/gtest_overload_evict_tcp_sess.cpp
+++ b/src/session/test/gtest_overload_evict_tcp_sess.cpp
@@ -1,10 +1,12 @@
 #include <gtest/gtest.h>
 
-#include "session_priv.h"
-#include "session_manager.h"
-
 #include "macro.h"
 #include "ipv4_utils.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
+#include "session_manager.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_overload_evict_udp_sess.cpp b/src/session/test/gtest_overload_evict_udp_sess.cpp
index de10da9..e0713c4 100644
--- a/src/session/test/gtest_overload_evict_udp_sess.cpp
+++ b/src/session/test/gtest_overload_evict_udp_sess.cpp
@@ -1,10 +1,12 @@
 #include <gtest/gtest.h>
 
-#include "session_priv.h"
-#include "session_manager.h"
-
 #include "macro.h"
 #include "ipv4_utils.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
+#include "session_manager.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_sess_mgr_tcp_reassembly.cpp b/src/session/test/gtest_sess_mgr_tcp_reassembly.cpp
index 731c77f..493a8c2 100644
--- a/src/session/test/gtest_sess_mgr_tcp_reassembly.cpp
+++ b/src/session/test/gtest_sess_mgr_tcp_reassembly.cpp
@@ -1,9 +1,12 @@
 #include <gtest/gtest.h>
 
-#include "session_priv.h"
-#include "session_manager.h"
-
 #include "ipv4_utils.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
+#include "session_manager.h"
+#include "tcp_reassembly.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_session.cpp b/src/session/test/gtest_session.cpp
index 72430b0..afd8625 100644
--- a/src/session/test/gtest_session.cpp
+++ b/src/session/test/gtest_session.cpp
@@ -1,6 +1,7 @@
 #include <gtest/gtest.h>
 
-#include "session_priv.h"
+#include "session_def.h"
+#include "session_utils.h"
 
 #define SESSION_KEY_IPV4_TCP(name)                        \
     struct tuple6 name;                                   \
@@ -57,7 +58,7 @@ TEST(SESSION, EX_NEW_INDEX)
 TEST(SESSION, EX_SET_GET)
 {
     struct session sess;
-    memset(&sess, 0, sizeof(sess));
+    session_init(&sess);
     uint8_t idx = session_get_ex_new_index("ex_set_get", NULL, NULL);
     session_set_ex_data(&sess, idx, (void *)0x1234);
     EXPECT_TRUE(session_get0_ex_data(&sess, idx) == (void *)0x1234);
@@ -66,7 +67,7 @@ TEST(SESSION, EX_SET_GET)
 TEST(SESSION, EX_FREE_BY_RESET)
 {
     struct session sess;
-    memset(&sess, 0, sizeof(sess));
+    session_init(&sess);
     uint8_t idx = session_get_ex_new_index("ex_free_by_reset", free_ex_data, NULL);
     char *ptr = strdup("hello");
     session_set_ex_data(&sess, idx, ptr);
@@ -76,7 +77,7 @@ TEST(SESSION, EX_FREE_BY_RESET)
 TEST(SESSION, EX_FREE_BY_CB)
 {
     struct session sess;
-    memset(&sess, 0, sizeof(sess));
+    session_init(&sess);
     uint8_t idx = session_get_ex_new_index("ex_free_by_cb", free_ex_data, NULL);
     char *ptr = strdup("hello");
     session_set_ex_data(&sess, idx, ptr);
diff --git a/src/session/test/gtest_session_table.cpp b/src/session/test/gtest_session_table.cpp
index 477766f..3f7e866 100644
--- a/src/session/test/gtest_session_table.cpp
+++ b/src/session/test/gtest_session_table.cpp
@@ -1,5 +1,7 @@
 #include <gtest/gtest.h>
 
+#include "tuple.h"
+#include "session_utils.h"
 #include "session_pool.h"
 #include "session_table.h"
 
@@ -112,17 +114,17 @@ TEST(SESSION_TABLE, OP_SESSION)
     sess1 = session_pool_pop(sess_pool);
     EXPECT_TRUE(sess1 != NULL);
     session_set_id(sess1, 1);
-    session_set_tuple(sess1, &sess1_tup6);
+    session_set_tuple6(sess1, &sess1_tup6);
 
     sess2 = session_pool_pop(sess_pool);
     EXPECT_TRUE(sess2 != NULL);
     session_set_id(sess2, 2);
-    session_set_tuple(sess2, &sess2_tup6);
+    session_set_tuple6(sess2, &sess2_tup6);
 
     sess3 = session_pool_pop(sess_pool);
     EXPECT_TRUE(sess3 != NULL);
     session_set_id(sess3, 3);
-    session_set_tuple(sess3, &sess3_tup6);
+    session_set_tuple6(sess3, &sess3_tup6);
 
     session_table_add(sess_table, sess1);
     EXPECT_TRUE(session_table_get_count(sess_table) == 1);
@@ -206,21 +208,21 @@ TEST(SESSION_TABLE, FIND_OLDEST_NEWEST)
     sess1 = session_pool_pop(sess_pool);
     EXPECT_TRUE(sess1 != NULL);
     session_set_id(sess1, 1);
-    session_set_tuple(sess1, &sess1_tup6);
+    session_set_tuple6(sess1, &sess1_tup6);
     session_table_add(sess_table, sess1);
     EXPECT_TRUE(session_table_find_lru(sess_table) == sess1);
 
     sess2 = session_pool_pop(sess_pool);
     EXPECT_TRUE(sess2 != NULL);
     session_set_id(sess2, 2);
-    session_set_tuple(sess2, &sess2_tup6);
+    session_set_tuple6(sess2, &sess2_tup6);
     session_table_add(sess_table, sess2);
     EXPECT_TRUE(session_table_find_lru(sess_table) == sess1);
 
     sess3 = session_pool_pop(sess_pool);
     EXPECT_TRUE(sess3 != NULL);
     session_set_id(sess3, 3);
-    session_set_tuple(sess3, &sess3_tup6);
+    session_set_tuple6(sess3, &sess3_tup6);
     session_table_add(sess_table, sess3);
     EXPECT_TRUE(session_table_find_lru(sess_table) == sess1);
 
diff --git a/src/session/test/gtest_session_timer.cpp b/src/session/test/gtest_session_timer.cpp
index c0b4804..6a5e757 100644
--- a/src/session/test/gtest_session_timer.cpp
+++ b/src/session/test/gtest_session_timer.cpp
@@ -1,5 +1,7 @@
 #include <gtest/gtest.h>
 
+#include "session_def.h"
+#include "session_utils.h"
 #include "session_timer.h"
 
 TEST(SESSION_TIMER, EXPIRE)
diff --git a/src/session/test/gtest_state_tcp_active_to_closing.cpp b/src/session/test/gtest_state_tcp_active_to_closing.cpp
index dfb36d7..aa0dc8d 100644
--- a/src/session/test/gtest_state_tcp_active_to_closing.cpp
+++ b/src/session/test/gtest_state_tcp_active_to_closing.cpp
@@ -1,11 +1,14 @@
 // TCP state machine test: active -> closing
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
-#include "session_manager.h"
-
 #include "tcp_utils.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
+#include "session_manager.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_state_tcp_init_to_opening.cpp b/src/session/test/gtest_state_tcp_init_to_opening.cpp
index 027dae7..a03243b 100644
--- a/src/session/test/gtest_state_tcp_init_to_opening.cpp
+++ b/src/session/test/gtest_state_tcp_init_to_opening.cpp
@@ -1,11 +1,14 @@
 // TCP state machine test: init -> opening
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
-#include "session_manager.h"
-
 #include "ipv4_utils.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
+#include "session_manager.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_state_tcp_init_to_opening_to_active_to_closing_to_closed.cpp b/src/session/test/gtest_state_tcp_init_to_opening_to_active_to_closing_to_closed.cpp
index c319049..5562e5d 100644
--- a/src/session/test/gtest_state_tcp_init_to_opening_to_active_to_closing_to_closed.cpp
+++ b/src/session/test/gtest_state_tcp_init_to_opening_to_active_to_closing_to_closed.cpp
@@ -1,10 +1,13 @@
 // TCP state machine test: init -> opening -> active -> closing -> closed
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
 #include "session_manager.h"
-
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_state_tcp_opening_to_active.cpp b/src/session/test/gtest_state_tcp_opening_to_active.cpp
index c086a6b..ede25e5 100644
--- a/src/session/test/gtest_state_tcp_opening_to_active.cpp
+++ b/src/session/test/gtest_state_tcp_opening_to_active.cpp
@@ -1,10 +1,13 @@
 // TCP state machine test: opening -> active
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
 #include "session_manager.h"
-
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_state_tcp_opening_to_closing.cpp b/src/session/test/gtest_state_tcp_opening_to_closing.cpp
index 3b772eb..2e820dc 100644
--- a/src/session/test/gtest_state_tcp_opening_to_closing.cpp
+++ b/src/session/test/gtest_state_tcp_opening_to_closing.cpp
@@ -1,11 +1,14 @@
 // TCP state machine test: opening -> closing
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
-#include "session_manager.h"
-
 #include "tcp_utils.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
+#include "session_manager.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_state_udp_init_to_opening_to_active_to_closing.cpp b/src/session/test/gtest_state_udp_init_to_opening_to_active_to_closing.cpp
index 01de7a8..146605a 100644
--- a/src/session/test/gtest_state_udp_init_to_opening_to_active_to_closing.cpp
+++ b/src/session/test/gtest_state_udp_init_to_opening_to_active_to_closing.cpp
@@ -1,10 +1,13 @@
 // UDP state machine test: init -> opening -> active -> closing
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
 #include "session_manager.h"
-
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_state_udp_init_to_opening_to_closing.cpp b/src/session/test/gtest_state_udp_init_to_opening_to_closing.cpp
index f461a86..f7b5cf0 100644
--- a/src/session/test/gtest_state_udp_init_to_opening_to_closing.cpp
+++ b/src/session/test/gtest_state_udp_init_to_opening_to_closing.cpp
@@ -1,10 +1,13 @@
 // UDP state machine test: init -> opening -> closing
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
 #include "session_manager.h"
-
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_timeout_tcp_data.cpp b/src/session/test/gtest_timeout_tcp_data.cpp
index 6e2cd31..ae88c81 100644
--- a/src/session/test/gtest_timeout_tcp_data.cpp
+++ b/src/session/test/gtest_timeout_tcp_data.cpp
@@ -1,9 +1,12 @@
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
 #include "session_manager.h"
-
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_timeout_tcp_handshake.cpp b/src/session/test/gtest_timeout_tcp_handshake.cpp
index 598e818..2cc0c20 100644
--- a/src/session/test/gtest_timeout_tcp_handshake.cpp
+++ b/src/session/test/gtest_timeout_tcp_handshake.cpp
@@ -1,10 +1,12 @@
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
 #include "session_manager.h"
-
-#include "ipv4_utils.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_timeout_tcp_init.cpp b/src/session/test/gtest_timeout_tcp_init.cpp
index 29ae072..2bf3dc8 100644
--- a/src/session/test/gtest_timeout_tcp_init.cpp
+++ b/src/session/test/gtest_timeout_tcp_init.cpp
@@ -1,10 +1,12 @@
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
 #include "session_manager.h"
-
-#include "ipv4_utils.h"
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/gtest_timeout_udp_data.cpp b/src/session/test/gtest_timeout_udp_data.cpp
index 6debd1a..5cad862 100644
--- a/src/session/test/gtest_timeout_udp_data.cpp
+++ b/src/session/test/gtest_timeout_udp_data.cpp
@@ -1,9 +1,12 @@
 #include <gtest/gtest.h>
 
+#include "tuple.h"
 #include "times.h"
-#include "session_priv.h"
+#include "packet_def.h"
+#include "packet_parse.h"
+#include "packet_layer.h"
+#include "session_utils.h"
 #include "session_manager.h"
-
 #include "test_packets.h"
 
 struct session_manager_options opts = {
diff --git a/src/session/test/test_packets.h b/src/session/test/test_packets.h
index 12a62ed..e2f0225 100644
--- a/src/session/test/test_packets.h
+++ b/src/session/test/test_packets.h
@@ -5,9 +5,6 @@ extern "C"
 {
 #endif
 
-#include "packet_parse.h"
-#include "packet_layer.h"
-
 /******************************************************************************
  * test packet: HTTP www.example.com
  ******************************************************************************/
diff --git a/src/stellar/config.cpp b/src/stellar/config.cpp
index 23dbe43..d211257 100644
--- a/src/stellar/config.cpp
+++ b/src/stellar/config.cpp
@@ -2,8 +2,12 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "config.h"
+#include "log.h"
 #include "toml.h"
+#include "config.h"
+
+#define CONFIG_LOG_ERROR(format, ...) LOG_ERROR("config", format, ##__VA_ARGS__)
+#define CONFIG_LOG_DEBUG(format, ...) LOG_DEBUG("config", format, ##__VA_ARGS__)
 
 // return  0: success
 // retuun -1: failed
diff --git a/src/stellar/config.h b/src/stellar/config.h
index dc7c822..abc61f8 100644
--- a/src/stellar/config.h
+++ b/src/stellar/config.h
@@ -9,9 +9,6 @@ extern "C"
 #include "ip_reassembly.h"
 #include "session_manager.h"
 
-#define CONFIG_LOG_ERROR(format, ...) LOG_ERROR("config", format, ##__VA_ARGS__)
-#define CONFIG_LOG_DEBUG(format, ...) LOG_DEBUG("config", format, ##__VA_ARGS__)
-
 struct device_options
 {
     uint8_t base;
diff --git a/src/stellar/inject.cpp b/src/stellar/inject.cpp
index 1fa56e6..2765dd4 100644
--- a/src/stellar/inject.cpp
+++ b/src/stellar/inject.cpp
@@ -1,12 +1,17 @@
 #include <errno.h>
 #include <assert.h>
 
+#include "log.h"
 #include "times.h"
 #include "packet_io.h"
 #include "packet_def.h"
 #include "packet_build.h"
-#include "session_priv.h"
-#include "stellar_priv.h"
+#include "packet_utils.h"
+#include "session_def.h"
+#include "session_utils.h"
+#include "stellar_utils.h"
+#include "tcp_reassembly.h"
+#include "session_manager.h"
 
 #define INJECT_PACKET_LOG_ERROR(format, ...) LOG_ERROR("inject packet", format, ##__VA_ARGS__)
 #define INJECT_PACKE_LOG_DEBUG(format, ...) LOG_DEBUG("inject packet", format, ##__VA_ARGS__)
diff --git a/src/stellar/main.cpp b/src/stellar/main.cpp
index 3b86339..48a0b79 100644
--- a/src/stellar/main.cpp
+++ b/src/stellar/main.cpp
@@ -1,4 +1,4 @@
-#include "stellar_priv.h"
+#include "stellar_utils.h"
 
 int main(int argc, char **argv)
 {
diff --git a/src/stellar/stat.cpp b/src/stellar/stat.cpp
index fa20824..3246a88 100644
--- a/src/stellar/stat.cpp
+++ b/src/stellar/stat.cpp
@@ -1,11 +1,16 @@
 #include <errno.h>
-#include <unistd.h>
 #include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
 
+#include "log.h"
 #include "stat.h"
 #include "fieldstat/fieldstat_easy.h"
 #include "fieldstat/fieldstat_exporter.h"
 
+#define STAT_LOG_ERROR(format, ...) LOG_ERROR("stat", format, ##__VA_ARGS__)
+
 #define IS_FREE 0
 #define IS_BUSY 0xf
 
diff --git a/src/stellar/stat.h b/src/stellar/stat.h
index c8983c8..c7623f5 100644
--- a/src/stellar/stat.h
+++ b/src/stellar/stat.h
@@ -9,8 +9,6 @@ extern "C"
 #include "ip_reassembly.h"
 #include "session_manager.h"
 
-#define STAT_LOG_ERROR(format, ...) LOG_ERROR("stat", format, ##__VA_ARGS__)
-
 struct thread_stat
 {
     struct io_stat *io;
diff --git a/src/stellar/stellar.cpp b/src/stellar/stellar.cpp
index 5fc9938..b48af57 100644
--- a/src/stellar/stellar.cpp
+++ b/src/stellar/stellar.cpp
@@ -1,18 +1,28 @@
 #include <errno.h>
+#include <stdio.h>
 #include <assert.h>
 #include <unistd.h>
-#include <pthread.h>
+#include <string.h>
 #include <signal.h>
+#include <pthread.h>
 #include <sys/prctl.h>
 
+#include "log.h"
 #include "stat.h"
 #include "logo.h"
 #include "times.h"
 #include "config.h"
+#include "packet_def.h"
+#include "packet_utils.h"
+#include "session_utils.h"
 #include "id_generator.h"
-#include "stellar_priv.h"
+#include "stellar_utils.h"
 #include "plugin_manager.h"
 
+#define STELLAR_LOG_STATE(format, ...) LOG_STATE("stellar", format, ##__VA_ARGS__)
+#define STELLAR_LOG_ERROR(format, ...) LOG_ERROR("stellar", format, ##__VA_ARGS__)
+#define STELLAR_LOG_DEBUG(format, ...) LOG_DEBUG("stellar", format, ##__VA_ARGS__)
+
 struct stellar_thread
 {
     pthread_t tid;
@@ -426,7 +436,6 @@ int stellar_main(int argc, char **argv)
         goto error_out;
     }
     stellar_print_config(config);
-    STELLAR_LOG_DEBUG("sizeof(struct session) = %lu bytes", sizeof(struct session));
 
     if (id_generator_init(config->dev_opts.base, config->dev_opts.offset) != 0)
     {
diff --git a/src/stellar/stellar_priv.h b/src/stellar/stellar_utils.h
similarity index 66%
rename from src/stellar/stellar_priv.h
rename to src/stellar/stellar_utils.h
index 3017199..b646e7c 100644
--- a/src/stellar/stellar_priv.h
+++ b/src/stellar/stellar_utils.h
@@ -7,16 +7,14 @@ extern "C"
 
 #include "stellar/stellar.h"
 
-#define STELLAR_LOG_STATE(format, ...) LOG_STATE("stellar", format, ##__VA_ARGS__)
-#define STELLAR_LOG_ERROR(format, ...) LOG_ERROR("stellar", format, ##__VA_ARGS__)
-#define STELLAR_LOG_DEBUG(format, ...) LOG_DEBUG("stellar", format, ##__VA_ARGS__)
-
 struct packet_io *stellar_get_packet_io(const struct stellar *st);
 struct session_manager *stellar_get_session_manager(const struct stellar *st);
 struct plugin_manager_schema *stellar_get_plugin_manager(const struct stellar *st);
 // TODO fix plugin manager, delete this function
 void stellar_set_plugin_manger(struct stellar *st, struct plugin_manager_schema *plug_mgr);
 
+int stellar_main(int argc, char **argv);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/tcp_reassembly/tcp_reassembly.cpp b/src/tcp_reassembly/tcp_reassembly.cpp
index 10ef79b..0cf3b3a 100644
--- a/src/tcp_reassembly/tcp_reassembly.cpp
+++ b/src/tcp_reassembly/tcp_reassembly.cpp
@@ -1,8 +1,12 @@
 #include <string.h>
 
+#include "log.h"
 #include "list.h"
-#include "tcp_reassembly.h"
 #include "interval_tree.h"
+#include "tcp_reassembly.h"
+
+#define TCP_REASSEMBLY_LOG_DEBUG(format, ...) LOG_DEBUG("tcp_reassembly", format, ##__VA_ARGS__)
+#define TCP_REASSEMBLY_LOG_ERROR(format, ...) LOG_ERROR("tcp_reassembly", format, ##__VA_ARGS__)
 
 struct tcp_segment_private
 {
diff --git a/src/tcp_reassembly/tcp_reassembly.h b/src/tcp_reassembly/tcp_reassembly.h
index f135274..65a7a35 100644
--- a/src/tcp_reassembly/tcp_reassembly.h
+++ b/src/tcp_reassembly/tcp_reassembly.h
@@ -7,11 +7,6 @@ extern "C"
 
 #include <stdint.h>
 
-#include "log.h"
-
-#define TCP_REASSEMBLY_LOG_DEBUG(format, ...) LOG_DEBUG("tcp_reassembly", format, ##__VA_ARGS__)
-#define TCP_REASSEMBLY_LOG_ERROR(format, ...) LOG_ERROR("tcp_reassembly", format, ##__VA_ARGS__)
-
 struct tcp_segment
 {
      uint32_t len;
diff --git a/test/packet_inject/packet_inject_main.cpp b/test/packet_inject/packet_inject_main.cpp
index dbb17a2..0b1f591 100644
--- a/test/packet_inject/packet_inject_main.cpp
+++ b/test/packet_inject/packet_inject_main.cpp
@@ -3,7 +3,7 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "stellar_priv.h"
+#include "stellar_utils.h"
 #include "packet_inject_main.h"
 
 struct packet_inject_rule rule = {0};