Adds configurable SO_REUSEADDR option. references XRPLF#311

Author: zaphoyd

changelog.md

@@ -11,6 +11,8 @@ HEAD
 - Feature: Adds the ability to pause reading on a connection. Paused connections will not
   read more data from their socket, allowing TCP flow control to work without blocking
   the main thread.
+- Feature: Adds the ability to specify whether or not to use the `SO_REUSEADDR` TCP socket
+  option. The default for this value has been changed from `true` to `false`.
 - Improvement: Open, close, and pong timeouts can be disabled entirely by setting their
   duration to 0.
 - Improvement: Numerous performance improvements. Including: tuned default

test/transport/integration.cpp

@@ -108,6 +108,7 @@ void run_server(server * s, int port, bool log = false) {
     }
 
     s->init_asio();
+    s->set_reuse_addr(true);
 
     s->listen(port);
     s->start_accept();
@@ -124,6 +125,7 @@ void run_client(client & c, std::string uri, bool log = false) {
     }
     websocketpp::lib::error_code ec;
     c.init_asio(ec);
+    c.set_reuse_addr(true);
     BOOST_CHECK(!ec);
 
     client::connection_ptr con = c.get_connection(uri,ec);

websocketpp/transport/asio/endpoint.hpp

@@ -91,6 +91,7 @@ class endpoint : public config::socket_type {
     explicit endpoint()
       : m_external_io_service(false)
       , m_listen_backlog(0)
+      , m_reuse_addr(false)
       , m_state(UNINITIALIZED)
     {
         //std::cout << "transport::asio::endpoint constructor" << std::endl;
@@ -123,6 +124,7 @@ class endpoint : public config::socket_type {
       , m_external_io_service(src.m_external_io_service)
       , m_acceptor(src.m_acceptor)
       , m_listen_backlog(0)
+      , m_reuse_addr(src.m_reuse_addr)
       , m_state(src.m_state)
     {
         src.m_io_service = NULL;
@@ -137,6 +139,7 @@ class endpoint : public config::socket_type {
             m_external_io_service = rhs.m_external_io_service;
             m_acceptor = rhs.m_acceptor;
             m_listen_backlog = rhs.m_listen_backlog
+            m_reuse_addr = rhs.m_reuse_addr;
             m_state = rhs.m_state;
 
             rhs.m_io_service = NULL;
@@ -287,6 +290,24 @@ class endpoint : public config::socket_type {
     void set_listen_backlog(int backlog) {
         m_listen_backlog = backlog;
     }
+    
+    /// Sets whether or not to use the SO_REUSEADDR flag when opening a listening socket
+    /**
+     * Specifies whether or not to use the SO_REUSEADDR TCP socket option. What this flag
+     * does depends on your operating system. Please consult operating system
+     * documentation for more details.
+     *
+     * New values affect future calls to listen only.
+     *
+     * The default is false.
+     *
+     * @since 0.4.0-alpha1
+     *
+     * @param value Whether or not to use the SO_REUSEADDR option
+     */
+    void set_reuse_addr(bool value) {
+        m_reuse_addr = value;
+    }
 
     /// Retrieve a reference to the endpoint's io_service
     /**
@@ -324,7 +345,7 @@ class endpoint : public config::socket_type {
         m_alog->write(log::alevel::devel,"asio::listen");
 
         m_acceptor->open(ep.protocol());
-        m_acceptor->set_option(boost::asio::socket_base::reuse_address(true));
+        m_acceptor->set_option(boost::asio::socket_base::reuse_address(m_reuse_addr));
         m_acceptor->bind(ep);
         if (m_listen_backlog == 0) {
             m_acceptor->listen();
@@ -1024,6 +1045,7 @@ class endpoint : public config::socket_type {
 
     // Network constants
     int                 m_listen_backlog;
+    bool                m_reuse_addr;
 
     elog_type* m_elog;
     alog_type* m_alog;