From 85a9da6f27cc447f796a5a051c56d67a1b20aba9 Mon Sep 17 00:00:00 2001
From: Eric Frias <efrias@syncad.com>
Date: Wed, 9 Apr 2014 18:29:59 -0400
Subject: [PATCH] Add to tcp_socket to enable TCP keepalives

---
 include/fc/network/tcp_socket.hpp |  3 ++-
 src/network/tcp_socket.cpp        | 38 +++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/include/fc/network/tcp_socket.hpp b/include/fc/network/tcp_socket.hpp
index a6affb3..3229f87 100644
--- a/include/fc/network/tcp_socket.hpp
+++ b/include/fc/network/tcp_socket.hpp
@@ -2,6 +2,7 @@
 #include <fc/utility.hpp>
 #include <fc/fwd.hpp>
 #include <fc/io/iostream.hpp>
+#include <fc/time.hpp>
 
 namespace fc {
   namespace ip { class endpoint; } 
@@ -13,6 +14,7 @@ namespace fc {
 
       void     connect_to( const fc::ip::endpoint& remote_endpoint );
       void     connect_to( const fc::ip::endpoint& remote_endpoint, const fc::ip::endpoint& local_endpoint );
+      void     enable_keep_alives(const fc::microseconds& interval);
       fc::ip::endpoint remote_endpoint()const;
 
       void get( char& c )
@@ -58,7 +60,6 @@ namespace fc {
       void     listen( uint16_t port );
       void     listen( const fc::ip::endpoint& ep );
       uint16_t get_port()const;
-    
     private:
       // non copyable
       tcp_server( const tcp_server& ); 
diff --git a/src/network/tcp_socket.cpp b/src/network/tcp_socket.cpp
index e71d759..0cca7bc 100644
--- a/src/network/tcp_socket.cpp
+++ b/src/network/tcp_socket.cpp
@@ -6,6 +6,10 @@
 #include <fc/io/stdio.hpp>
 #include <fc/exception/exception.hpp>
 
+#if defined _WIN32 || defined WIN32 || defined OS_WIN64 || defined _WIN64 || defined WIN64 || defined WINNT
+# include <MSTcpIP.h>
+#endif
+
 namespace fc {
 
   class tcp_socket::impl {
@@ -64,6 +68,40 @@ namespace fc {
     fc::asio::tcp::connect(my->_sock, fc::asio::tcp::endpoint( boost::asio::ip::address_v4(remote_endpoint.get_address()), remote_endpoint.port() ) ); 
   }
 
+  void tcp_socket::enable_keep_alives(const fc::microseconds& interval)
+  {
+    if (interval.count())
+    {
+      boost::asio::socket_base::keep_alive option(true);
+      my->_sock.set_option(option);
+#if defined _WIN32 || defined WIN32 || defined OS_WIN64 || defined _WIN64 || defined WIN64 || defined WINNT
+      struct tcp_keepalive keepalive_settings;
+      keepalive_settings.onoff = 1;
+      keepalive_settings.keepalivetime = interval.count() / fc::milliseconds(1).count();
+      keepalive_settings.keepaliveinterval = interval.count() / fc::milliseconds(1).count();
+
+      DWORD dwBytesRet = 0;
+      if (WSAIoctl(my->_sock.native(), SIO_KEEPALIVE_VALS, &keepalive_settings, sizeof(keepalive_settings),
+                   NULL, 0, &dwBytesRet, NULL, NULL) == SOCKET_ERROR)
+        wlog("Error setting TCP keepalive values");
+#else
+      // This should work for modern Linuxes and for OSX >= Mountain Lion
+      int timeout_sec = interval.count() / fc::seconds(1).count();
+      if (setsockopt(my->_sock.native(), SOL_TCP, TCP_KEEPIDLE, 
+                     (char*)&timeout_sec, sizeof(timeout_sec)) < 0)
+        wlog("Error setting TCP keepalive idle time");
+      if (setsockopt(my->_sock.native(), SOL_TCP, TCP_KEEPINTVL, 
+                     (char*)&timeout_sec, sizeof(timeout_sec)) < 0)
+        wlog("Error setting TCP keepalive interval");
+#endif
+    }
+    else
+    {
+      boost::asio::socket_base::keep_alive option(false);
+      my->_sock.set_option(option);
+    }
+  }
+
   class tcp_server::impl {
     public:
       impl(uint16_t port)