clean up broadcasting

include/libtorrent/broadcast_socket.hpp

@@ -70,7 +70,9 @@ namespace libtorrent
 			, receive_handler_t const& handler, bool loopback = true);
 		~broadcast_socket() { close(); }
 
-		void send(char const* buffer, int size, error_code& ec);
+		enum flags_t { broadcast = 1 };
+		void send(char const* buffer, int size, error_code& ec, int flags = 0);
+
 		void close();
 		int num_send_sockets() const { return m_unicast_sockets.size(); }
 		void enable_ip_broadcast(bool e);
@@ -80,19 +82,27 @@ namespace libtorrent
 		struct socket_entry
 		{
 			socket_entry(boost::shared_ptr<datagram_socket> const& s)
-				: socket(s) {}
+				: socket(s), broadcast(false) {}
 			socket_entry(boost::shared_ptr<datagram_socket> const& s
-				, address_v4 const& mask): socket(s), netmask(mask) {}
+				, address_v4 const& mask): socket(s), netmask(mask), broadcast(false) {}
 			boost::shared_ptr<datagram_socket> socket;
-			char buffer[1024];
+			char buffer[1500];
 			udp::endpoint remote;
 			address_v4 netmask;
+			bool broadcast;
 			void close()
 			{
 				if (!socket) return;
 				error_code ec;
 				socket->close(ec);
 			}
+			bool can_broadcast() const
+			{
+				error_code ec;
+				return broadcast
+					&& netmask != address_v4()
+					&& socket->local_endpoint(ec).address().is_v4();
+			}
 			address_v4 broadcast_address() const
 			{
 				error_code ec;
@@ -118,12 +128,6 @@ namespace libtorrent
 		std::list<socket_entry> m_unicast_sockets;
 		udp::endpoint m_multicast_endpoint;
 		receive_handler_t m_on_receive;
-
-		// if set, use IP broadcast as well as IP multicast
-		// this is off by default because it's expensive in
-		// terms of bandwidth usage
-		bool m_ip_broadcast;
-		
 	};
 }
 	

src/broadcast_socket.cpp

@@ -205,7 +205,6 @@ namespace libtorrent
 		, bool loopback)
 		: m_multicast_endpoint(multicast_endpoint)
 		, m_on_receive(handler)
-		, m_ip_broadcast(false)
 	{
 		TORRENT_ASSERT(is_multicast(m_multicast_endpoint.address()));
 
@@ -232,9 +231,10 @@ namespace libtorrent
 			ec = error_code();
 			open_multicast_socket(ios, i->interface_address, loopback, ec);
 #ifndef NDEBUG
-//			fprintf(stderr, "broadcast socket [ if: %s group: %s ] %s\n"
+//			fprintf(stderr, "broadcast socket [ if: %s group: %s mask: %s ] %s\n"
 //				, i->interface_address.to_string().c_str()
-//				, print_address(multicast_endpoint.address()).c_str()
+//				, multicast_endpoint.address().to_string().c_str()
+//				, i->netmask.to_string().c_str()
 //				, ec.message().c_str());
 #endif
 			open_unicast_socket(ios, i->interface_address
@@ -242,21 +242,6 @@ namespace libtorrent
 		}
 	}
 
-	void broadcast_socket::enable_ip_broadcast(bool e)
-	{
-		if (e == m_ip_broadcast) return;
-		m_ip_broadcast = e;
-
-		asio::socket_base::broadcast option(m_ip_broadcast);
-		error_code ec;
-		for (std::list<socket_entry>::iterator i = m_unicast_sockets.begin()
-			, end(m_unicast_sockets.end()); i != end; ++i)
-		{
-			if (!i->socket) continue;
-			i->socket->set_option(option, ec);
-		}
-	}
-
 	void broadcast_socket::open_multicast_socket(io_service& ios
 		, address const& addr, bool loopback, error_code& ec)
 	{
@@ -294,8 +279,15 @@ namespace libtorrent
 		if (ec) return;
 		s->bind(udp::endpoint(addr, 0), ec);
 		if (ec) return;
+
 		m_unicast_sockets.push_back(socket_entry(s, mask));
 		socket_entry& se = m_unicast_sockets.back();
+
+		// allow sending broadcast messages
+		asio::socket_base::broadcast option(true);
+		s->set_option(option, ec);
+		if (!ec) se.broadcast = true;
+
 #if defined TORRENT_ASIO_DEBUGGING
 		add_outstanding_async("broadcast_socket::on_receive");
 #endif
@@ -303,7 +295,7 @@ namespace libtorrent
 			, se.remote, boost::bind(&broadcast_socket::on_receive, this, &se, _1, _2));
 	}
 
-	void broadcast_socket::send(char const* buffer, int size, error_code& ec)
+	void broadcast_socket::send(char const* buffer, int size, error_code& ec, int flags)
 	{
 		for (std::list<socket_entry>::iterator i = m_unicast_sockets.begin()
 			, end(m_unicast_sockets.end()); i != end; ++i)
@@ -311,6 +303,13 @@ namespace libtorrent
 			if (!i->socket) continue;
 			error_code e;
 			i->socket->send_to(asio::buffer(buffer, size), m_multicast_endpoint, 0, e);
+
+			// if the user specified the broadcast flag, send one to the broadcast
+			// address as well
+			if ((flags & broadcast_socket::broadcast) && i->can_broadcast())
+				i->socket->send_to(asio::buffer(buffer, size)
+					, udp::endpoint(i->broadcast_address(), m_multicast_endpoint.port()), 0, e);
+
 #ifndef NDEBUG
 //			fprintf(stderr, " sending on unicast %s to: %s\n", print_address(i->socket->local_endpoint().address()).c_str()
 //				, print_endpoint(m_multicast_endpoint).c_str());
@@ -331,9 +330,6 @@ namespace libtorrent
 			if (!i->socket) continue;
 			error_code e;
 			i->socket->send_to(asio::buffer(buffer, size), m_multicast_endpoint, 0, e);
-			if (m_ip_broadcast && i->socket->local_endpoint(e).address().is_v4())
-				i->socket->send_to(asio::buffer(buffer, size)
-					, udp::endpoint(i->broadcast_address(), m_multicast_endpoint.port()), 0, e);
 #ifndef NDEBUG
 //			extern std::string print_address(address const& addr);
 //			extern std::string print_endpoint(udp::endpoint const& ep);

src/lsd.cpp

@@ -98,8 +98,7 @@ void lsd::announce(sha1_hash const& ih, int listen_port, bool broadcast)
 
 	m_retry_count = 1;
 	error_code ec;
-	m_socket.enable_ip_broadcast(broadcast);
-	m_socket.send(msg, msg_len, ec);
+	m_socket.send(msg, msg_len, ec, broadcast ? broadcast_socket::broadcast : 0);
 	if (ec)
 	{
 		m_disabled = true;
@@ -131,8 +130,6 @@ void lsd::resend_announce(error_code const& e, std::string msg)
 	if (e) return;
 
 	error_code ec;
-	// don't broadcast resends
-	m_socket.enable_ip_broadcast(false);
 	m_socket.send(msg.c_str(), int(msg.size()), ec);
 
 	++m_retry_count;