From d2e3d21a85bd2e92c9f5e7835eda6fa3ce451831 Mon Sep 17 00:00:00 2001
From: LiPeng <lipeng@espressif.com>
Date: Wed, 20 Dec 2023 11:37:41 +0800
Subject: [PATCH] tcp: Apply faster PCB recycling in FIN_WAIT_1 or FIN_WAIT_2
 state

---
 src/core/tcp.c | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/core/tcp.c b/src/core/tcp.c
index 3fbdd89ae..fe6baaf25 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -1765,7 +1765,9 @@ tcp_kill_state(enum tcp_state state)
   struct tcp_pcb *pcb, *inactive;
   u32_t inactivity;
 
+#if !ESP_LWIP
   LWIP_ASSERT("invalid state", (state == CLOSING) || (state == LAST_ACK));
+#endif
 
   inactivity = 0;
   inactive = NULL;
@@ -1870,17 +1872,41 @@ tcp_alloc(u8_t prio)
         tcp_kill_state(CLOSING);
         /* Try to allocate a tcp_pcb again. */
         pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+#if ESP_LWIP
         if (pcb == NULL) {
-          /* Try killing oldest active connection with lower priority than the new one. */
-          LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing oldest connection with prio lower than %d\n", prio));
-          tcp_kill_prio(prio);
-          /* Try to allocate a tcp_pcb again. */
+          /* Try killing oldest connection in FIN_WAIT_2. */
+          LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest FIN_WAIT_2 connection\n"));
+          tcp_kill_state(FIN_WAIT_2);
           pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+          if (pcb == NULL) {
+            /* Try killing oldest connection in FIN_WAIT_1. */
+            LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest FIN_WAIT_1 connection\n"));
+            tcp_kill_state(FIN_WAIT_1);
+            pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+#endif
+            if (pcb == NULL) {
+              /* Try killing oldest active connection with lower priority than the new one. */
+              LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing oldest connection with prio lower than %d\n", prio));
+              tcp_kill_prio(prio);
+              /* Try to allocate a tcp_pcb again. */
+              pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+              if (pcb != NULL) {
+                /* adjust err stats: memp_malloc failed multiple times before */
+                MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+              }
+            }
+#if ESP_LWIP
+            if (pcb != NULL) {
+            /* adjust err stats: memp_malloc failed multiple times before */
+            MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+            }
+          }
           if (pcb != NULL) {
             /* adjust err stats: memp_malloc failed multiple times before */
             MEMP_STATS_DEC(err, MEMP_TCP_PCB);
           }
         }
+#endif
         if (pcb != NULL) {
           /* adjust err stats: memp_malloc failed multiple times before */
           MEMP_STATS_DEC(err, MEMP_TCP_PCB);