From 417a6078a8168951a0a9e2b69996409c7bc65ef7 Mon Sep 17 00:00:00 2001
From: yuanjm <yuanjianmin@espressif.com>
Date: Thu, 26 Mar 2020 11:58:18 +0800
Subject: [PATCH] feat(lwip): Add kconfig to congigure initial RTO time and set
 default value to 1000

---
 components/lwip/Kconfig                         | 7 +++++++
 components/lwip/lwip/src/core/tcp.c             | 5 +++--
 components/lwip/lwip/src/include/lwip/opt.h     | 5 +++++
 components/lwip/port/esp8266/include/lwipopts.h | 6 ++++++
 4 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/components/lwip/Kconfig b/components/lwip/Kconfig
index 0006c006..3f442249 100644
--- a/components/lwip/Kconfig
+++ b/components/lwip/Kconfig
@@ -479,6 +479,13 @@ config LWIP_TCP_TIMESTAMPS
         really used locally. Therefore, it is only enabled when a TS option is
         received in the initial SYN packet from a remote host.
 
+config LWIP_TCP_RTO_TIME
+    int "Default TCP RTO TIME"
+    default 1000
+    help
+        Set default TCP RTO time for a reasonable initial RTO.
+        Advise to set initial RTO to 1 second
+
 endmenu # TCP
 
 menu "UDP"
diff --git a/components/lwip/lwip/src/core/tcp.c b/components/lwip/lwip/src/core/tcp.c
index fba9d99e..3af362d7 100644
--- a/components/lwip/lwip/src/core/tcp.c
+++ b/components/lwip/lwip/src/core/tcp.c
@@ -1630,8 +1630,9 @@ tcp_alloc(u8_t prio)
     /* As initial send MSS, we use TCP_MSS but limit it to 536.
        The send MSS is updated when an MSS option is received. */
     pcb->mss = INITIAL_MSS;
-    pcb->rto = 3000 / TCP_SLOW_INTERVAL;
-    pcb->sv = 3000 / TCP_SLOW_INTERVAL;
+    /* make TCP's retransmission time to be configurable */
+    pcb->rto = LWIP_TCP_RTO_TIME / TCP_SLOW_INTERVAL;
+    pcb->sv = LWIP_TCP_RTO_TIME / TCP_SLOW_INTERVAL;
     pcb->rtime = -1;
     pcb->cwnd = 1;
     pcb->tmr = tcp_ticks;
diff --git a/components/lwip/lwip/src/include/lwip/opt.h b/components/lwip/lwip/src/include/lwip/opt.h
index 8f8b0777..634ae70b 100644
--- a/components/lwip/lwip/src/include/lwip/opt.h
+++ b/components/lwip/lwip/src/include/lwip/opt.h
@@ -1350,6 +1350,11 @@
 #define LWIP_WND_SCALE                  0
 #define TCP_RCV_SCALE                   0
 #endif
+
+#if !defined LWIP_TCP_RTO_TIME || defined __DOXYGEN__
+#define LWIP_TCP_RTO_TIME             3000
+#endif
+
 /**
  * @}
  */
diff --git a/components/lwip/port/esp8266/include/lwipopts.h b/components/lwip/port/esp8266/include/lwipopts.h
index 970ac342..60eaf9e7 100644
--- a/components/lwip/port/esp8266/include/lwipopts.h
+++ b/components/lwip/port/esp8266/include/lwipopts.h
@@ -1097,6 +1097,12 @@ size_t memp_malloc_get_size(size_t type);
  */
 #define LWIP_WND_SCALE                  0
 #define TCP_RCV_SCALE                   0
+
+/**
+ * LWIP_TCP_RTO_TIME: make TCP RTO time configurable.
+ * Default is 1 second.
+ */
+#define LWIP_TCP_RTO_TIME             CONFIG_LWIP_TCP_RTO_TIME
 /**
  * @}
  */