added option to control TOS byte in peer traffic

include/libtorrent/proxy_base.hpp

@@ -101,6 +101,20 @@ public:
 		m_sock.async_write_some(buffers, handler);
 	}
 
+#ifndef BOOST_NO_EXCEPTIONS
+	template <class SettableSocketOption>
+	void set_option(SettableSocketOption const& opt)
+	{
+		m_sock.set_option(opt);
+	}
+#endif
+
+	template <class SettableSocketOption>
+	asio::error_code set_option(SettableSocketOption const& opt, asio::error_code& ec)
+	{
+		return m_sock.set_option(opt, ec);
+	}
+
 #ifndef BOOST_NO_EXCEPTIONS
 	void bind(endpoint_type const& endpoint)
 	{

include/libtorrent/session_settings.hpp

@@ -127,6 +127,7 @@ namespace libtorrent
 			, cache_size(512)
 			, cache_expiry(60)
 			, outgoing_ports(0,0)
+			, peer_tos(0)
 		{}
 
 		// this is the user agent that will be sent to the tracker
@@ -339,6 +340,13 @@ namespace libtorrent
 		// is useful for users that have routers that
 		// allow QoS settings based on local port.
 		std::pair<int, int> outgoing_ports;
+
+		// the TOS byte of all peer traffic (including
+		// web seeds) is set to this value. The default
+		// is the QBSS scavenger service
+		// http://qbone.internet2.edu/qbss/
+		// For unmarked packets, set to 0
+		char peer_tos;
 	};
 	
 #ifndef TORRENT_DISABLE_DHT

include/libtorrent/socket.hpp

@@ -185,6 +185,19 @@ namespace libtorrent
 		int m_value;
 	};
 	
+	struct type_of_service
+	{
+		type_of_service(char val): m_value(val) {}
+		template<class Protocol>
+		int level(Protocol const&) const { return IPPROTO_IP; }
+		template<class Protocol>
+		int name(Protocol const&) const { return IP_TOS; }
+		template<class Protocol>
+		char const* data(Protocol const&) const { return &m_value; }
+		template<class Protocol>
+		size_t size(Protocol const&) const { return sizeof(m_value); }
+		char m_value;
+	};
 }
 
 #endif // TORRENT_SOCKET_HPP_INCLUDED

include/libtorrent/variant_stream.hpp

@@ -256,6 +256,45 @@ namespace aux
       { return EndpointType(); }
   };
 
+// -------------- set_option -----------
+
+  template <class SettableSocketOption>
+  struct set_option_visitor
+    : boost::static_visitor<>
+  {
+      set_option_visitor(SettableSocketOption const& opt)
+        : opt_(opt)
+      {}
+
+      template <class T>
+      void operator()(T* p) const
+      { p->set_option(opt_); }
+
+		std::size_t operator()(boost::blank) const {}
+
+      SettableSocketOption const& opt_;
+  };
+
+  template <class SettableSocketOption>
+  struct set_option_visitor_ec
+    : boost::static_visitor<asio::error_code>
+  {
+      set_option_visitor_ec(SettableSocketOption const& opt, asio::error_code& ec)
+        : opt_(opt)
+        , ec_(ec)
+      {}
+
+      template <class T>
+      asio::error_code operator()(T* p) const
+      { return p->set_option(opt_, ec_); }
+
+		asio::error_code operator()(boost::blank) const
+      { return ec_; }
+
+      SettableSocketOption const& opt_;
+      asio::error_code& ec_;
+  };
+
 // -------------- local_endpoint -----------
 
   template <class EndpointType>
@@ -657,6 +696,22 @@ public:
         );
     }
 
+    template <class SettableSocketOption>
+    void set_option(SettableSocketOption const& opt)
+    {
+        TORRENT_ASSERT(instantiated());
+        boost::apply_visitor(aux::set_option_visitor<SettableSocketOption>(opt)
+            , m_variant);
+    }
+
+    template <class SettableSocketOption>
+    asio::error_code set_option(SettableSocketOption const& opt, asio::error_code& ec)
+    {
+        TORRENT_ASSERT(instantiated());
+        return boost::apply_visitor(aux::set_option_visitor_ec<SettableSocketOption>(opt, ec)
+            , m_variant);
+    }
+	 
     endpoint_type local_endpoint() const
     {
         TORRENT_ASSERT(instantiated());