From a1658663728447810dbdcd7a5b547ccd0dfd23f4 Mon Sep 17 00:00:00 2001
From: xueyunfei <xueyunfei@espressif.com>
Date: Wed, 31 Aug 2022 17:28:17 +0800
Subject: [PATCH] Lwip:add TCP Fin2 timeout configuration

* Update submodule: git log --oneline 76303df2386902e0d7873be4217f1d9d1b50f982..6132c9755a43d4e04de4457f1558ced415756e4d

Detailed description of the changes:
  - napt: Fix clean compilation  (espressif/esp-lwip@6132c975)
  - Lwip:add TCP Fin2 timeout configuration (espressif/esp-lwip@15b4400e)
  - napt: Fix IP forwarding when forward netif enable NAPT (espressif/esp-lwip@c950063f)
  - napt/stats: Move some napt counters to stats module (espressif/esp-lwip@475d658a)
  - ip_napt_maint: Fix timestamp overflow handling (espressif/esp-lwip@2e904508)
  - napt: Fixes and improvements (espressif/esp-lwip@fb1f3552)
---
 components/lwip/Kconfig                       | 8 +++++++-
 components/lwip/lwip                          | 2 +-
 components/lwip/port/esp32/include/lwipopts.h | 5 +++++
 docs/en/api-guides/lwip.rst                   | 1 +
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/components/lwip/Kconfig b/components/lwip/Kconfig
index 57e8c2b045..7c15daa570 100644
--- a/components/lwip/Kconfig
+++ b/components/lwip/Kconfig
@@ -506,7 +506,13 @@ menu "LWIP"
             int "Maximum segment lifetime (MSL)"
             default 60000
             help
-                Set maximum segment lifetime in in milliseconds.
+                Set maximum segment lifetime in milliseconds.
+
+        config LWIP_TCP_FIN_WAIT_TIMEOUT
+            int "Maximum FIN segment lifetime"
+            default 20000
+            help
+                Set maximum segment lifetime in milliseconds.
 
         config LWIP_TCP_SND_BUF_DEFAULT
             int "Default send buffer size"
diff --git a/components/lwip/lwip b/components/lwip/lwip
index 76303df238..6132c9755a 160000
--- a/components/lwip/lwip
+++ b/components/lwip/lwip
@@ -1 +1 @@
-Subproject commit 76303df2386902e0d7873be4217f1d9d1b50f982
+Subproject commit 6132c9755a43d4e04de4457f1558ced415756e4d
diff --git a/components/lwip/port/esp32/include/lwipopts.h b/components/lwip/port/esp32/include/lwipopts.h
index bb0d371c6e..511d4fc0dd 100644
--- a/components/lwip/port/esp32/include/lwipopts.h
+++ b/components/lwip/port/esp32/include/lwipopts.h
@@ -359,6 +359,11 @@
  */
 #define TCP_MSL                         CONFIG_LWIP_TCP_MSL
 
+/**
+ * TCP_FIN_WAIT_TIMEOUT: The maximum FIN segment lifetime in milliseconds
+ */
+#define TCP_FIN_WAIT_TIMEOUT            CONFIG_LWIP_TCP_FIN_WAIT_TIMEOUT
+
 /**
  * TCP_MAXRTX: Maximum number of retransmissions of data segments.
  */
diff --git a/docs/en/api-guides/lwip.rst b/docs/en/api-guides/lwip.rst
index ecae070395..ae517d0800 100644
--- a/docs/en/api-guides/lwip.rst
+++ b/docs/en/api-guides/lwip.rst
@@ -439,6 +439,7 @@ Most lwIP RAM usage is on-demand, as RAM is allocated from the heap as needed. T
 
 - Reducing :ref:`CONFIG_LWIP_MAX_SOCKETS` reduces the maximum number of sockets in the system. This will also cause TCP sockets in the ``WAIT_CLOSE`` state to be closed and recycled more rapidly (if needed to open a new socket), further reducing peak RAM usage.
 - Reducing :ref:`CONFIG_LWIP_TCPIP_RECVMBOX_SIZE`, :ref:`CONFIG_LWIP_TCP_RECVMBOX_SIZE` and :ref:`CONFIG_LWIP_UDP_RECVMBOX_SIZE` reduce memory usage at the expense of throughput, depending on usage.
+- Reducing :ref:`CONFIG_LWIP_TCP_MSL`, :ref:`CONFIG_LWIP_TCP_FIN_WAIT_TIMEOUT` reduces the maximum segment lifetime in the system. This will also cause TCP sockets in the ``TIME_WAIT``, ``FIN_WAIT_2`` state to be closed and recycled more rapidly 
 - Disable  :ref:`CONFIG_LWIP_IPV6` can save about 39 KB for firmware size and 2KB RAM when system power up and 7KB RAM when TCPIP stack running. If there is no requirement for supporting IPV6 then it can be disabled to save flash and RAM footprint.
 
 If using Wi-Fi, please also refer to :ref:`wifi-buffer-usage`.