From 85fe75d1cbaf372f0a98558adcd5a612a0e19602 Mon Sep 17 00:00:00 2001
From: ShadowNinja <shadowninja@minetest.net>
Date: Wed, 5 Feb 2014 21:24:46 +0100
Subject: Add the option to bind to a specific address

---
 src/connection.cpp      | 27 ++++++++++++++++++---------
 src/connection.h        |  9 ++++-----
 src/defaultsettings.cpp |  1 +
 src/game.cpp            | 26 +++++++++++++++++++++++---
 src/main.cpp            | 17 ++++++++++++++++-
 src/server.cpp          | 10 ++++++----
 src/server.h            |  2 +-
 src/socket.cpp          | 27 +++++++++++++++++++--------
 src/socket.h            |  2 +-
 src/test.cpp            |  9 ++++++---
 10 files changed, 95 insertions(+), 35 deletions(-)

(limited to 'src')

diff --git a/src/connection.cpp b/src/connection.cpp
index 92f9f8ec2..f8c68ed2e 100644
--- a/src/connection.cpp
+++ b/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);
-		serve(c.port);
+				<<c.address.serializeString()<<std::endl);
+		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);
 }
 
diff --git a/src/connection.h b/src/connection.h
index c9474032d..9d646f499 100644
--- a/src/connection.h
+++ b/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();
diff --git a/src/defaultsettings.cpp b/src/defaultsettings.cpp
index bac5e0e2d..9d1aadad9 100644
--- a/src/defaultsettings.cpp
+++ b/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");
diff --git a/src/game.cpp b/src/game.cpp
index 56519d30a..b540e3314 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -909,8 +909,8 @@ bool nodePlacementPrediction(Client &client,
 
 			// Dont place node when player would be inside new node
 			// NOTE: This is to be eventually implemented by a mod as client-side Lua
-			if (!nodedef->get(n).walkable || 
-				(client.checkPrivilege("noclip") && g_settings->getBool("noclip")) || 
+			if (!nodedef->get(n).walkable ||
+				(client.checkPrivilege("noclip") && g_settings->getBool("noclip")) ||
 				(nodedef->get(n).walkable &&
 				neighbourpos != player->getStandingNodePos() + v3s16(0,1,0) &&
 				neighbourpos != player->getStandingNodePos() + v3s16(0,2,0))) {
@@ -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))
diff --git a/src/main.cpp b/src/main.cpp
index 8186e26c8..b5de4b93f 100644
--- a/src/main.cpp
+++ b/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);
diff --git a/src/server.cpp b/src/server.cpp
index 00db9128d..151bcada1 100644
--- a/src/server.cpp
+++ b/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()
diff --git a/src/server.h b/src/server.h
index 19bedf74a..54078defc 100644
--- a/src/server.h
+++ b/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.
diff --git a/src/socket.cpp b/src/socket.cpp
index 78ff364e5..00856fb00 100644
--- a/src/socket.cpp
+++ b/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)
@@ -347,12 +358,12 @@ 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(port);
+		address.sin6_port   = htons(addr.getPort());
 
 		if(bind(m_handle, (const struct sockaddr *) &address,
-		        sizeof(struct sockaddr_in6)) < 0)
+				sizeof(struct sockaddr_in6)) < 0)
 		{
 			dstream << (int) m_handle << ": Bind failed: "
 			        << strerror(errno) << std::endl;
@@ -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(port);
+		address.sin_port        = htons(addr.getPort());
 
 		if(bind(m_handle, (const struct sockaddr *) &address,
 		        sizeof(struct sockaddr_in)) < 0)
diff --git a/src/socket.h b/src/socket.h
index ba88b0142..7d35a32da 100644
--- a/src/socket.h
+++ b/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);
diff --git a/src/test.cpp b/src/test.cpp
index c969c0951..dd2691947 100644
--- a/src/test.cpp
+++ b/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);
-- 
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