diff --git a/include/stellar/session.h b/include/stellar/session.h
index 10bd35c..182677a 100644
--- a/include/stellar/session.h
+++ b/include/stellar/session.h
@@ -149,6 +149,8 @@ uint64_t session_get_stat(const struct session *sess, enum flow_direction dir, e
 
 const char *session_get0_readable_addr(const struct session *sess);
 
+void session_set_discard(struct session *sess);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/session/session_manager.cpp b/src/session/session_manager.cpp
index 5fd61e1..d708004 100644
--- a/src/session/session_manager.cpp
+++ b/src/session/session_manager.cpp
@@ -700,6 +700,7 @@ static struct session *session_manager_new_tcp_session(struct session_manager *m
           return NULL;
      }
      session_init(sess);
+     sess->mgr = mgr;
      sess->mgr_stat = &mgr->stat;
 
      enum session_state next_state = session_transition_run(SESSION_STATE_INIT, TCP_SYN);
@@ -746,6 +747,7 @@ static struct session *session_manager_new_udp_session(struct session_manager *m
           return NULL;
      }
      session_init(sess);
+     sess->mgr = mgr;
      sess->mgr_stat = &mgr->stat;
 
      enum flow_direction dir = identify_direction_by_port(ntohs(key->src_port), ntohs(key->dst_port));
@@ -1168,3 +1170,29 @@ struct session_manager_stat *session_manager_stat(struct session_manager *mgr)
 {
      return &mgr->stat;
 }
+
+void session_set_discard(struct session *sess)
+{
+     uint64_t now = stellar_get_monotonic_time_msec();
+     struct session_manager *mgr = sess->mgr;
+     enum session_type type = session_get_type(sess);
+     enum session_state curr_state = session_get_current_state(sess);
+     enum session_state next_state = session_transition_run(curr_state, USER_CLOSE);
+     session_transition_log(sess, curr_state, next_state, USER_CLOSE);
+     session_set_current_state(sess, next_state);
+
+     switch (type)
+     {
+     case SESSION_TYPE_TCP:
+          session_timer_update(mgr->sess_timer, sess, now + mgr->opts.tcp_discard_timeout);
+          SESS_MGR_STAT_UPDATE(&mgr->stat, curr_state, next_state, tcp);
+          break;
+     case SESSION_TYPE_UDP:
+          session_timer_update(mgr->sess_timer, sess, now + mgr->opts.udp_discard_timeout);
+          SESS_MGR_STAT_UPDATE(&mgr->stat, curr_state, next_state, udp);
+          break;
+     default:
+          assert(0);
+          break;
+     }
+}
diff --git a/src/session/session_priv.h b/src/session/session_priv.h
index 41d6c59..d2f1092 100644
--- a/src/session/session_priv.h
+++ b/src/session/session_priv.h
@@ -76,6 +76,7 @@ struct session
     enum session_type type;
     enum session_state state;
     enum closing_reason reason;
+    struct session_manager *mgr;
     struct session_manager_stat *mgr_stat;
 };
 
diff --git a/src/stellar/stellar.cpp b/src/stellar/stellar.cpp
index 2b81ce1..95af957 100644
--- a/src/stellar/stellar.cpp
+++ b/src/stellar/stellar.cpp
@@ -178,6 +178,10 @@ static void *work_thread(void *arg)
 
         fast_path:
             plugin_manager_on_session_egress(sess, pkt);
+            if (sess && session_get_current_state(sess) == SESSION_STATE_DISCARD)
+            {
+                packet_set_action(pkt, PACKET_ACTION_DROP);
+            }
             update_session_stat(sess, pkt);
             if (packet_get_action(pkt) == PACKET_ACTION_DROP)
             {
@@ -218,11 +222,7 @@ static void *work_thread(void *arg)
 
         merge_thread_stat(thread, now);
         ip_reassembly_expire(ip_reass, now);
-
-        // TODO
         plugin_manager_on_polling(runtime->plug_mgr);
-        // session_manager_cron();
-        // poll_non_packet_events();
 
         if (nr_recv == 0)
         {
diff --git a/test/packet_injector.cpp b/test/packet_injector.cpp
index 4475597..91c2e4b 100644
--- a/test/packet_injector.cpp
+++ b/test/packet_injector.cpp
@@ -54,7 +54,7 @@ static void inject_packet_plugin(struct session *sess, int topic_id, const void
 {
     char buffer[1024] = {0};
     struct inject_rule *p_rule = &rule;
-    struct packet *pkt = (struct packet *)msg;
+    // struct packet *pkt = (struct packet *)msg;
     const struct tuple6 *tuple = session_get_tuple6(sess);
     if (p_rule->ip_type == 4 &&
         memcmp(&tuple->src_addr.v4, &p_rule->v4, sizeof(struct in_addr)) &&
@@ -75,8 +75,6 @@ static void inject_packet_plugin(struct session *sess, int topic_id, const void
     if (session_get_stat(sess, FLOW_DIRECTION_C2S, STAT_INJECTED_PACKETS_SUCCESS) > 0 ||
         session_get_stat(sess, FLOW_DIRECTION_S2C, STAT_INJECTED_PACKETS_SUCCESS) > 0)
     {
-        // later packets need drop
-        packet_set_action(pkt, PACKET_ACTION_DROP);
         return;
     }
     if (p_rule->count_dir == AFTER_RECV_C2S_N_PACKET && session_get_stat(sess, FLOW_DIRECTION_C2S, STAT_RAW_PACKETS_RECEIVED) != p_rule->count_num)
@@ -90,31 +88,27 @@ static void inject_packet_plugin(struct session *sess, int topic_id, const void
     switch (p_rule->inject_type)
     {
     case INJECT_TYPE_TCP_RST:
-        // current packet need drop
-        packet_set_action(pkt, PACKET_ACTION_DROP);
         EXPECT_TRUE(stellar_inject_tcp_rst(sess, FLOW_DIRECTION_C2S) > 0);
         EXPECT_TRUE(stellar_inject_tcp_rst(sess, FLOW_DIRECTION_S2C) > 0);
+        session_set_discard(sess);
         break;
     case INJECT_TYPE_TCP_FIN:
-        // current packet need drop
-        packet_set_action(pkt, PACKET_ACTION_DROP);
         EXPECT_TRUE(stellar_inject_tcp_fin(sess, FLOW_DIRECTION_C2S) > 0);
         EXPECT_TRUE(stellar_inject_tcp_fin(sess, FLOW_DIRECTION_S2C) > 0);
+        session_set_discard(sess);
         break;
     case INJECT_TYPE_TCP_PAYLOAD:
-        // current packet need drop
-        packet_set_action(pkt, PACKET_ACTION_DROP);
         snprintf(buffer, sizeof(buffer), "HTTP/1.1 200 OK\r\nContent-Length: %d\r\n\r\n%s", 5 + 5 + 2, "Hello");
         EXPECT_TRUE(stellar_inject_payload(sess, FLOW_DIRECTION_S2C, buffer, strlen(buffer)) > 0); // inject payload to client
-        EXPECT_TRUE(stellar_inject_payload(sess, FLOW_DIRECTION_S2C, "World\r\n", 7) > 0);
-        EXPECT_TRUE(stellar_inject_tcp_fin(sess, FLOW_DIRECTION_S2C) > 0); // inject FIN to client
-        EXPECT_TRUE(stellar_inject_tcp_rst(sess, FLOW_DIRECTION_C2S) > 0); // inject RST to server
+        EXPECT_TRUE(stellar_inject_payload(sess, FLOW_DIRECTION_S2C, "World\r\n", 7) > 0);         // inject payload to client
+        EXPECT_TRUE(stellar_inject_tcp_rst(sess, FLOW_DIRECTION_S2C) > 0);                         // inject RST to client
+        EXPECT_TRUE(stellar_inject_tcp_rst(sess, FLOW_DIRECTION_C2S) > 0);                         // inject RST to server
+        session_set_discard(sess);
         break;
     case INJECT_TYPE_UDP_PAYLOAD:
-        // current packet need drop
-        packet_set_action(pkt, PACKET_ACTION_DROP);
         EXPECT_TRUE(stellar_inject_payload(sess, FLOW_DIRECTION_C2S, "Hello Server", 12) > 0);
         EXPECT_TRUE(stellar_inject_payload(sess, FLOW_DIRECTION_S2C, "Hello Client", 12) > 0);
+        session_set_discard(sess);
         break;
     case INJECT_TYPE_CTRL_MSG:
         // TOOD