From 2f00c1d8d9819bed703f61259c484e26268f0f88 Mon Sep 17 00:00:00 2001
From: Yury Popov <github@phoenix.dj>
Date: Fri, 17 Mar 2017 09:31:37 +0300
Subject: [PATCH] TIME_WAIT sockets fixes (#1838)

* Enable SO_REUSEADDR for server TCP sockets

* Reduce TCP_MSL to 5 sec

* Add changes notice for future updates

* Move MSL change to lwipiots.h
---
 app/include/lwipopts.h | 12 +++++++++++-
 app/modules/net.c      |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/app/include/lwipopts.h b/app/include/lwipopts.h
index 23f731ad..3cb93b73 100755
--- a/app/include/lwipopts.h
+++ b/app/include/lwipopts.h
@@ -899,6 +899,15 @@
 #define TCP_TTL                         (IP_DEFAULT_TTL)
 #endif
 
+/**
+ * TCP_MSL: Maximum segment lifetime
+ * Override for <tcp_impl.h> file
+ * See https://github.com/nodemcu/nodemcu-firmware/issues/1836 for details
+ */
+#ifndef TCP_MSL
+#define TCP_MSL 5000UL
+#endif
+
 /**
  * TCP_MAXRTX: Maximum number of retransmissions of data segments.
  */
@@ -1455,7 +1464,8 @@
  * SO_REUSE==1: Enable SO_REUSEADDR option.
  */
 #ifndef SO_REUSE
-#define SO_REUSE                        0
+/* See https://github.com/nodemcu/nodemcu-firmware/issues/1836 for details */
+#define SO_REUSE                        1
 #endif
 
 /**
diff --git a/app/modules/net.c b/app/modules/net.c
index 4a3c65cc..90c25d26 100644
--- a/app/modules/net.c
+++ b/app/modules/net.c
@@ -386,6 +386,7 @@ int net_listen( lua_State *L ) {
       ud->tcp_pcb = tcp_new();
       if (!ud->tcp_pcb)
         return luaL_error(L, "cannot allocate PCB");
+      ud->tcp_pcb->so_options |= SOF_REUSEADDR;
       err = tcp_bind(ud->tcp_pcb, &addr, port);
       if (err == ERR_OK) {
         tcp_arg(ud->tcp_pcb, ud);