Add the option to bind to a specific address

builtin/mainmenu.lua

@@ -626,6 +626,9 @@ function tabbuilder.handle_server_buttons(fields)
 			gamedata.selected_world	= filterlist.get_raw_index(worldlist,selected)
 
 			engine.setting_set("port",gamedata.port)
+			if fields["te_serveraddr"] ~= nil then
+				engine.setting_set("bind_address",fields["te_serveraddr"])
+			end
 
 			menu.update_last_game(gamedata.selected_world)
 			engine.start()
@@ -950,11 +953,24 @@ function tabbuilder.tab_server()
 		dump(engine.setting_getbool("enable_damage")) .. "]"..
 		"checkbox[0.5,1.15;cb_server_announce;".. fgettext("Public") .. ";" ..
 		dump(engine.setting_getbool("server_announce")) .. "]"..
-		"field[0.8,3.2;3,0.5;te_playername;".. fgettext("Name") .. ";" ..
+		"field[0.8,3.2;3.5,0.5;te_playername;".. fgettext("Name") .. ";" ..
 		engine.setting_get("name") .. "]" ..
-		"pwdfield[0.8,4.2;3,0.5;te_passwd;".. fgettext("Password") .. "]" ..
+		"pwdfield[0.8,4.2;3.5,0.5;te_passwd;".. fgettext("Password") .. "]"
-		"field[0.8,5.2;3,0.5;te_serverport;".. fgettext("Server Port") .. ";" ..
+		
-		engine.setting_get("port") .."]" ..
+	local bind_addr = engine.setting_get("bind_address")
+	if bind_addr ~= nil and bind_addr ~= "" then
+		retval = retval ..
+			"field[0.8,5.2;2.25,0.5;te_serveraddr;".. fgettext("Bind Address") .. ";" ..
+			engine.setting_get("bind_address") .."]" ..
+			"field[3.05,5.2;1.25,0.5;te_serverport;".. fgettext("Port") .. ";" ..
+			engine.setting_get("port") .."]"
+	else
+		retval = retval ..
+			"field[0.8,5.2;3.5,0.5;te_serverport;".. fgettext("Server Port") .. ";" ..
+			engine.setting_get("port") .."]"
+	end
+	
+	retval = retval ..
 		"textlist[4,0.25;7.5,3.7;srv_worlds;" ..
 		menu.render_world_list() ..
 		";" .. index .. "]"

minetest.conf.example

@@ -231,7 +231,9 @@
 # Server stuff
 #
 # Network port to listen (UDP)
-#port =
+#port = 30000
+# Bind address
+#bind_address =
 # Name of server
 #server_name = Minetest server
 # Description of server

src/connection.cpp

@@ -1597,8 +1597,8 @@ void ConnectionSendThread::processNonReliableCommand(ConnectionCommand &c)
 		return;
 	case CONNCMD_SERVE:
 		LOG(dout_con<<m_connection->getDesc()<<" UDP processing CONNCMD_SERVE port="
-				<<c.port<<std::endl);
+				<<c.address.serializeString()<<std::endl);
-		serve(c.port);
+		serve(c.address);
 		return;
 	case CONNCMD_CONNECT:
 		LOG(dout_con<<m_connection->getDesc()<<" UDP processing CONNCMD_CONNECT"<<std::endl);
@@ -1631,11 +1631,12 @@ void ConnectionSendThread::processNonReliableCommand(ConnectionCommand &c)
 	}
 }
 
-void ConnectionSendThread::serve(u16 port)
+void ConnectionSendThread::serve(Address bind_address)
 {
-	LOG(dout_con<<m_connection->getDesc()<<"UDP serving at port "<<port<<std::endl);
+	LOG(dout_con<<m_connection->getDesc()
+			<<"UDP serving at port " << bind_address.serializeString() <<std::endl);
 	try{
-		m_connection->m_udpSocket.Bind(port);
+		m_connection->m_udpSocket.Bind(bind_address);
 		m_connection->SetPeerID(PEER_ID_SERVER);
 	}
 	catch(SocketException &e){
@@ -1658,7 +1659,14 @@ void ConnectionSendThread::connect(Address address)
 	e.peerAdded(peer->id, peer->address);
 	m_connection->putEvent(e);
 
-	m_connection->m_udpSocket.Bind(0);
+	Address bind_addr;
+
+	if (address.isIPv6())
+		bind_addr.setAddress((IPv6AddressBytes*) NULL);
+	else
+		bind_addr.setAddress(0,0,0,0);
+
+	m_connection->m_udpSocket.Bind(bind_addr);
 
 	// Send a dummy packet to server with peer_id = PEER_ID_INEXISTENT
 	m_connection->SetPeerID(PEER_ID_INEXISTENT);
@@ -1716,7 +1724,8 @@ void ConnectionSendThread::send(u16 peer_id, u8 channelnum,
 	assert(channelnum < CHANNEL_COUNT);
 
 	PeerHelper peer = m_connection->getPeerNoEx(peer_id);
-	if(!peer) {
+	if(!peer)
+	{
 		LOG(dout_con<<m_connection->getDesc()<<" peer: peer_id="<<peer_id
 				<< ">>>NOT<<< found on sending packet"
 				<< ", channel " << (channelnum % 0xFF)
@@ -2766,10 +2775,10 @@ void Connection::putCommand(ConnectionCommand &c)
 	}
 }
 
-void Connection::Serve(unsigned short port)
+void Connection::Serve(Address bind_addr)
 {
 	ConnectionCommand c;
-	c.serve(port);
+	c.serve(bind_addr);
 	putCommand(c);
 }
 

src/connection.h

@@ -406,7 +406,6 @@ enum ConnectionCommandType{
 struct ConnectionCommand
 {
 	enum ConnectionCommandType type;
-	u16 port;
 	Address address;
 	u16 peer_id;
 	u8 channelnum;
@@ -416,10 +415,10 @@ struct ConnectionCommand
 
 	ConnectionCommand(): type(CONNCMD_NONE), peer_id(PEER_ID_INEXISTENT), reliable(false), raw(false) {}
 
-	void serve(u16 port_)
+	void serve(Address address_)
 	{
 		type = CONNCMD_SERVE;
-		port = port_;
+		address = address_;
 	}
 	void connect(Address address_)
 	{
@@ -912,7 +911,7 @@ private:
 
 	void processReliableCommand (ConnectionCommand &c);
 	void processNonReliableCommand (ConnectionCommand &c);
-	void serve          (u16 port);
+	void serve          (Address bind_address);
 	void connect        (Address address);
 	void disconnect     ();
 	void disconnect_peer(u16 peer_id);
@@ -996,7 +995,7 @@ public:
 	void putCommand(ConnectionCommand &c);
 	
 	void SetTimeoutMs(int timeout){ m_bc_receive_timeout = timeout; }
-	void Serve(unsigned short port);
+	void Serve(Address bind_addr);
 	void Connect(Address address);
 	bool Connected();
 	void Disconnect();

src/defaultsettings.cpp

@@ -175,6 +175,7 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("workaround_window_size","5");
 	settings->setDefault("max_packets_per_iteration","1024");
 	settings->setDefault("port", "30000");
+	settings->setDefault("bind_address","");
 	settings->setDefault("default_game", "minetest");
 	settings->setDefault("motd", "");
 	settings->setDefault("max_users", "15");

src/game.cpp

@@ -1029,7 +1029,27 @@ void the_game(
 		infostream<<"Creating server"<<std::endl;
 		server = new Server(map_dir, gamespec,
 				simple_singleplayer_mode);
-		server->start(port);
+
+		std::string bind_str = g_settings->get("bind_address");
+		Address bind_addr(0,0,0,0, port);
+
+		if (bind_str != "")
+		{
+			try {
+				bind_addr.Resolve(bind_str.c_str());
+				address = bind_str;
+			} catch (ResolveError &e) {
+				infostream << "Resolving bind address \"" << bind_str
+						   << "\" failed: " << e.what()
+						   << " -- Listening on all addresses." << std::endl;
+
+				if (g_settings->getBool("ipv6_server")) {
+					bind_addr.setAddress((IPv6AddressBytes*) NULL);
+				}
+			}
+		}
+
+		server->start(bind_addr);
 	}
 
 	do{ // Client scope (breakable do-while(0))

src/main.cpp

@@ -1024,6 +1024,21 @@ int main(int argc, char *argv[])
 	if(port == 0)
 		port = 30000;
 
+	// Bind address
+	std::string bind_str = g_settings->get("bind_address");
+	Address bind_addr(0,0,0,0, port);
+	try {
+		bind_addr.Resolve(bind_str.c_str());
+	} catch (ResolveError &e) {
+		infostream << "Resolving bind address \"" << bind_str
+		           << "\" failed: " << e.what()
+		           << " -- Listening on all addresses." << std::endl;
+
+		if (g_settings->getBool("ipv6_server")) {
+			bind_addr.setAddress((IPv6AddressBytes*) NULL);
+		}
+	}
+
 	// World directory
 	std::string commanded_world = "";
 	if(cmd_args.exists("world"))
@@ -1270,7 +1285,7 @@ int main(int argc, char *argv[])
 			return 0;
 		}
 
-		server.start(port);
+		server.start(bind_addr);
 
 		// Run server
 		dedicated_server_loop(server, kill);

src/server.cpp

@@ -452,17 +452,18 @@ Server::~Server()
 	}
 }
 
-void Server::start(unsigned short port)
+void Server::start(Address bind_addr)
 {
 	DSTACK(__FUNCTION_NAME);
-	infostream<<"Starting server on port "<<port<<"..."<<std::endl;
+	infostream<<"Starting server on "
+			<< bind_addr.serializeString() <<"..."<<std::endl;
 
 	// Stop thread if already running
 	m_thread->Stop();
 
 	// Initialize connection
 	m_con.SetTimeoutMs(30);
-	m_con.Serve(port);
+	m_con.Serve(bind_addr);
 
 	// Start thread
 	m_thread->Start();
@@ -477,7 +478,8 @@ void Server::start(unsigned short port)
 	<<"      \\/        \\/     \\/          \\/     \\/        "<<std::endl;
 	actionstream<<"World at ["<<m_path_world<<"]"<<std::endl;
 	actionstream<<"Server for gameid=\""<<m_gamespec.id
-			<<"\" listening on port "<<port<<"."<<std::endl;
+			<<"\" listening on "<<bind_addr.serializeString()<<":"
+			<<bind_addr.getPort() << "."<<std::endl;
 }
 
 void Server::stop()

src/server.h

@@ -177,7 +177,7 @@ public:
 		bool simple_singleplayer_mode
 	);
 	~Server();
-	void start(unsigned short port);
+	void start(Address bind_addr);
 	void stop();
 	// This is mainly a way to pass the time to the server.
 	// Actual processing is done in an another thread.

src/socket.cpp

@@ -92,24 +92,27 @@ void sockets_cleanup()
 Address::Address()
 {
 	m_addr_family = 0;
-	memset(&m_address, 0, sizeof m_address);
+	memset(&m_address, 0, sizeof(m_address));
 	m_port = 0;
 }
 
 Address::Address(u32 address, u16 port)
 {
+	memset(&m_address, 0, sizeof(m_address));
 	setAddress(address);
 	setPort(port);
 }
 
 Address::Address(u8 a, u8 b, u8 c, u8 d, u16 port)
 {
+	memset(&m_address, 0, sizeof(m_address));
 	setAddress(a, b, c, d);
 	setPort(port);
 }
 
 Address::Address(const IPv6AddressBytes * ipv6_bytes, u16 port)
 {
+	memset(&m_address, 0, sizeof(m_address));
 	setAddress(ipv6_bytes);
 	setPort(port);
 }
@@ -334,12 +337,20 @@ UDPSocket::~UDPSocket()
 #endif
 }
 
-void UDPSocket::Bind(u16 port)
+void UDPSocket::Bind(Address addr)
 {
 	if(socket_enable_debug_output)
 	{
 		dstream << "UDPSocket(" << (int) m_handle << ")::Bind(): "
-		        << "port=" << port << std::endl;
+		        << addr.serializeString() << ":"
+		        << addr.getPort() << std::endl;
+	}
+
+	if (addr.getFamily() != m_addr_family)
+	{
+		char errmsg[] = "Socket and bind address families do not match";
+		errorstream << "Bind failed: " << errmsg << std::endl;
+		throw SocketException(errmsg);
 	}
 
 	if(m_addr_family == AF_INET6)
@@ -347,9 +358,9 @@ void UDPSocket::Bind(u16 port)
 		struct sockaddr_in6 address;
 		memset(&address, 0, sizeof(address));
 
+		address             = addr.getAddress6();
 		address.sin6_family = AF_INET6;
-		address.sin6_addr   = in6addr_any;
+		address.sin6_port   = htons(addr.getPort());
-		address.sin6_port   = htons(port);
 
 		if(bind(m_handle, (const struct sockaddr *) &address,
 				sizeof(struct sockaddr_in6)) < 0)
@@ -364,9 +375,9 @@ void UDPSocket::Bind(u16 port)
 		struct sockaddr_in address;
 		memset(&address, 0, sizeof(address));
 
+		address                 = addr.getAddress();
 		address.sin_family      = AF_INET;
-		address.sin_addr.s_addr = INADDR_ANY;
+		address.sin_port        = htons(addr.getPort());
-		address.sin_port        = htons(port);
 
 		if(bind(m_handle, (const struct sockaddr *) &address,
 		        sizeof(struct sockaddr_in)) < 0)

src/socket.h

@@ -115,7 +115,7 @@ class UDPSocket
 public:
 	UDPSocket(bool ipv6);
 	~UDPSocket();
-	void Bind(unsigned short port);
+	void Bind(Address addr);
 	//void Close();
 	//bool IsOpen();
 	void Send(const Address & destination, const void * data, int size);

src/test.cpp

@@ -1506,11 +1506,13 @@ struct TestSocket: public TestBase
 	void Run()
 	{
 		const int port = 30003;
+		Address address(0,0,0,0, port);
+		Address address6((IPv6AddressBytes*) NULL, port);
 
 		// IPv6 socket test
 		{
 			UDPSocket socket6(true);
-			socket6.Bind(port);
+			socket6.Bind(address6);
 
 			const char sendbuffer[] = "hello world!";
 			IPv6AddressBytes bytes;
@@ -1536,7 +1538,7 @@ struct TestSocket: public TestBase
 		// IPv4 socket test
 		{
 			UDPSocket socket(false);
-			socket.Bind(port);
+			socket.Bind(address);
 
 			const char sendbuffer[] = "hello world!";
 			socket.Send(Address(127,0,0,1,port), sendbuffer, sizeof(sendbuffer));
@@ -1656,7 +1658,8 @@ struct TestConnection: public TestBase
 		
 		infostream<<"** Creating server Connection"<<std::endl;
 		con::Connection server(proto_id, 512, 5.0, false, &hand_server);
-		server.Serve(30001);
+		Address address(0,0,0,0, 30001);
+		server.Serve(address);
 		
 		infostream<<"** Creating client Connection"<<std::endl;
 		con::Connection client(proto_id, 512, 5.0, false, &hand_client);