diff --git a/src/session/session.cpp b/src/session/session.cpp
index 168c13e..cdea80b 100644
--- a/src/session/session.cpp
+++ b/src/session/session.cpp
@@ -88,6 +88,17 @@ enum session_type session_get_type(const struct session *sess)
     return sess->type;
 }
 
+// closing reasion
+void session_set_closing_reasion(struct session *sess, enum closing_reasion reasion)
+{
+    sess->closing_reasion = reasion;
+}
+
+enum closing_reasion session_get_closing_reasion(const struct session *sess)
+{
+    return sess->closing_reasion;
+}
+
 // session metrics
 void session_inc_c2s_metrics(struct session *sess, uint64_t packets, uint64_t bytes)
 {
@@ -388,6 +399,27 @@ static void udp_ex_data_tostring(uint64_t ex_data, char *buffer, size_t buffer_l
     }
 }
 
+const char *session_closing_reasion_tostring(enum closing_reasion reasion)
+{
+    switch (reasion)
+    {
+    case CLOSING_BY_TIMEOUT:
+        return "CLOSING_BY_TIMEOUT";
+    case CLOSING_BY_EVICTED:
+        return "CLOSING_BY_EVICTED";
+    case CLOSING_BY_CLIENT_FIN:
+        return "CLOSING_BY_CLIENT_FIN";
+    case CLOSING_BY_CLIENT_RST:
+        return "CLOSING_BY_CLIENT_RST";
+    case CLOSING_BY_SERVER_FIN:
+        return "CLOSING_BY_SERVER_FIN";
+    case CLOSING_BY_SERVER_RST:
+        return "CLOSING_BY_SERVER_RST";
+    default:
+        return "unknown";
+    }
+}
+
 const char *session_state_tostring(enum session_state state)
 {
     switch (state)
@@ -445,6 +477,7 @@ void session_dump(struct session *sess)
     printf("session tuple6 dir         : %s\n", session_dir_tostring(session_get_tuple6_dir(sess)));
     printf("session state              : %s\n", session_state_tostring(session_get_state(sess)));
     printf("session type               : %s\n", session_type_tostring(session_get_type(sess)));
+    printf("session closing reasion    : %s\n", session_closing_reasion_tostring(session_get_closing_reasion(sess)));
     printf("session c2s packets        : %" PRIu64 "\n", session_get_c2s_packets(sess));
     printf("session c2s bytes          : %" PRIu64 "\n", session_get_c2s_bytes(sess));
     printf("session s2c packets        : %" PRIu64 "\n", session_get_s2c_packets(sess));
diff --git a/src/session/session.h b/src/session/session.h
index 26f1543..309c9ce 100644
--- a/src/session/session.h
+++ b/src/session/session.h
@@ -20,12 +20,6 @@ enum session_state
     SESSION_STATE_CLOSED,
 };
 
-enum session_action
-{
-    SESSION_ACTION_DISCARD,
-    SESSION_ACTION_FASTFORWARD,
-};
-
 enum session_type
 {
     SESSION_TYPE_TCP = 0x1,
@@ -39,6 +33,16 @@ enum session_dir
     SESSION_DIR_S2C = 2,
 };
 
+enum closing_reasion
+{
+    CLOSING_BY_TIMEOUT = 1,
+    CLOSING_BY_EVICTED = 2,
+    CLOSING_BY_CLIENT_FIN = 3,
+    CLOSING_BY_CLIENT_RST = 4,
+    CLOSING_BY_SERVER_FIN = 5,
+    CLOSING_BY_SERVER_RST = 6,
+};
+
 struct session;
 
 /******************************************************************************
@@ -65,6 +69,10 @@ enum session_state session_get_state(const struct session *sess);
 void session_set_type(struct session *sess, enum session_type type);
 enum session_type session_get_type(const struct session *sess);
 
+// closing reasion
+void session_set_closing_reasion(struct session *sess, enum closing_reasion reasion);
+enum closing_reasion session_get_closing_reasion(const struct session *sess);
+
 // session metrics
 void session_inc_c2s_metrics(struct session *sess, uint64_t packets, uint64_t bytes);
 void session_inc_s2c_metrics(struct session *sess, uint64_t packets, uint64_t bytes);
@@ -140,6 +148,7 @@ void session_run_expirecb(struct session *sess);
  * session dump
  ******************************************************************************/
 
+const char *session_closing_reasion_tostring(enum closing_reasion reasion);
 const char *session_state_tostring(enum session_state state);
 const char *session_type_tostring(enum session_type type);
 const char *session_dir_tostring(enum session_dir dir);
diff --git a/src/session/session_private.h b/src/session/session_private.h
index 0ab5fb5..18460a4 100644
--- a/src/session/session_private.h
+++ b/src/session/session_private.h
@@ -49,6 +49,9 @@ struct session
     // session type
     enum session_type type;
 
+    // closing reasion
+    enum closing_reasion closing_reasion;
+
     // session metrics
     uint64_t c2s_bytes;
     uint64_t s2c_bytes;