Add C4NetIOTCP::Bind() for binding without connect

src/network/C4NetIO.cpp

@@ -1151,20 +1151,77 @@ bool C4NetIOTCP::Execute(int iMaxTime, pollfd *fds) // (mt-safe)
 	return true;
 }
 
-bool C4NetIOTCP::Connect(const C4NetIO::addr_t &addr) // (mt-safe)
+C4NetIOTCP::Socket::~Socket()
+{
+	if (sock != INVALID_SOCKET)
+		closesocket(sock);
+}
+
+C4NetIO::addr_t C4NetIOTCP::Socket::GetAddress()
+{
+	sockaddr_in6 addr;
+	socklen_t address_len = sizeof addr;
+	C4NetIO::addr_t result;
+	if (::getsockname(sock, (sockaddr*) &addr, &address_len) != SOCKET_ERROR)
+	{
+		result.SetAddress((sockaddr*) &addr);
+	}
+	return result;
+}
+
+SOCKET C4NetIOTCP::CreateSocket(addr_t::AddressFamily family)
 {
 	// create new socket
-	SOCKET nsock = ::socket(addr.GetFamily() == HostAddress::IPv6 ? AF_INET6 : AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+	SOCKET nsock = ::socket(family == HostAddress::IPv6 ? AF_INET6 : AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
 	if (nsock == INVALID_SOCKET)
 	{
 		SetError("socket creation failed", true);
-		return false;
+		return INVALID_SOCKET;
 	}
 
-	if (addr.GetFamily() == HostAddress::IPv6)
+	if (family == HostAddress::IPv6)
 		if (!InitIPv6Socket(nsock))
-			return false;
+		{
+			closesocket(nsock);
+			return INVALID_SOCKET;
+		}
 
+	return nsock;
+}
+
+std::unique_ptr<C4NetIOTCP::Socket> C4NetIOTCP::Bind(const C4NetIO::addr_t &addr) // (mt-safe)
+{
+	SOCKET nsock = CreateSocket(addr.GetFamily());
+	if (nsock == INVALID_SOCKET) return nullptr;
+
+	// bind the socket to the given address
+	if (::bind(nsock, &addr, addr.GetAddrLen()) == SOCKET_ERROR)
+	{
+		SetError("binding the socket failed", true);
+		closesocket(nsock);
+		return nullptr;
+	}
+	return std::unique_ptr<Socket>(new Socket(nsock));
+}
+
+bool C4NetIOTCP::Connect(const addr_t &addr, std::unique_ptr<Socket> socket) // (mt-safe)
+{
+	SOCKET nsock = socket->sock;
+	socket->sock = INVALID_SOCKET;
+	return Connect(addr, nsock);
+}
+
+bool C4NetIOTCP::Connect(const C4NetIO::addr_t &addr) // (mt-safe)
+{
+	// create new socket
+	SOCKET nsock = CreateSocket(addr.GetFamily());
+	if (nsock == INVALID_SOCKET) return false;
+
+	return Connect(addr, nsock);
+}
+
+bool C4NetIOTCP::Connect(const C4NetIO::addr_t &addr, SOCKET nsock) // (mt-safe)
+{
 #ifdef STDSCHEDULER_USE_EVENTS
 	// set event
 	if (::WSAEventSelect(nsock, Event, FD_CONNECT) == SOCKET_ERROR)

src/network/C4NetIO.h

@@ -338,6 +338,18 @@ public:
 	C4NetIOTCP();
 	~C4NetIOTCP() override;
 
+	// Socket is an unconnected, but bound socket.
+	class Socket
+	{
+		SOCKET sock;
+		Socket(SOCKET s) : sock(s) { }
+		friend class C4NetIOTCP;
+	public:
+		~Socket();
+		// GetAddress returns the address the socket is bound to.
+		C4NetIO::addr_t GetAddress();
+	};
+
 	// *** interface
 
 	// * not multithreading safe
@@ -349,6 +361,8 @@ public:
 	bool Execute(int iMaxTime = TO_INF, pollfd * readyfds = nullptr) override;
 
 	// * multithreading safe
+	std::unique_ptr<Socket> Bind(const addr_t &addr);
+	bool Connect(const addr_t &addr, std::unique_ptr<Socket> socket);
 	bool Connect(const addr_t &addr) override;
 	bool Close(const addr_t &addr) override;
 
@@ -474,6 +488,9 @@ protected:
 
 	bool Listen(uint16_t inListenPort);
 
+	SOCKET CreateSocket(addr_t::AddressFamily family);
+	bool Connect(const addr_t &addr, SOCKET nsock);
+
 	Peer *Accept(SOCKET nsock = INVALID_SOCKET, const addr_t &ConnectAddr = addr_t());
 	Peer *GetPeer(const addr_t &addr);
 	void OnShareFree(CStdCSecEx *pCSec) override;

tests/C4NetIOTest.cpp

@@ -83,3 +83,21 @@ TEST_F(C4NetIOTest, HostAddressCategories)
 		EXPECT_TRUE(check(addr.IsPrivate(), t->priv));
 	}
 }
+
+
+// Tests C4NetIOTCP::Bind
+TEST_F(C4NetIOTest, TCPBind)
+{
+	C4NetIOTCP NetIO;
+	ASSERT_TRUE(NetIO.Init());
+
+	C4NetIO::addr_t addr(StdStrBuf("[::1]:0"));
+	auto socket = NetIO.Bind(addr);
+	ASSERT_NE(socket, nullptr);
+	auto bound_addr = socket->GetAddress();
+	EXPECT_TRUE(bound_addr.IsLoopback());
+	EXPECT_EQ(bound_addr.GetFamily(), C4NetIO::addr_t::IPv6);
+	EXPECT_NE(bound_addr.GetPort(), 0);
+
+	NetIO.Close();
+}