Fix windows debugger connection problems.

Unify network socket creation between platform.
Ensure IPV6_V6ONLY flag is not set on sockets (allow IPv4 connection in IPv6 socket, dual-stack).

(cherry picked from commit 812908e236e83db368dfef49b8badb9a6182e1de)

drivers/unix/packet_peer_udp_posix.cpp

@@ -121,8 +121,6 @@ int PacketPeerUDPPosix::get_max_packet_size() const{
 
 Error PacketPeerUDPPosix::listen(int p_port, IP_Address::AddrType p_address_type, int p_recv_buffer_size) {
 
-	ERR_FAIL_COND_V(p_address_type != IP_Address::TYPE_IPV4 && p_address_type != IP_Address::TYPE_IPV6, ERR_INVALID_PARAMETER);
-
 	close();
 	int sock = _get_socket(p_address_type);
 	if (sock == -1 )
@@ -223,11 +221,7 @@ int PacketPeerUDPPosix::_get_socket(IP_Address::AddrType p_type) {
 	if (sockfd != -1)
 		return sockfd;
 
-	int family = p_type == IP_Address::TYPE_IPV6 ? AF_INET6 : AF_INET;
-
-	sockfd = socket(family, SOCK_DGRAM, IPPROTO_UDP);
-	ERR_FAIL_COND_V( sockfd == -1, -1 );
-	//fcntl(sockfd, F_SETFL, O_NONBLOCK);
+	sockfd = _socket_create(p_type, SOCK_DGRAM, IPPROTO_UDP);
 
 	return sockfd;
 }

drivers/unix/socket_helpers.h

@@ -45,6 +45,27 @@ static size_t _set_listen_sockaddr(struct sockaddr_storage* p_addr, int p_port,
 	};
 };
 
+static int _socket_create(IP_Address::AddrType p_type, int type, int protocol) {
+
+	ERR_FAIL_COND_V(p_type > IP_Address::TYPE_ANY || p_type < IP_Address::TYPE_NONE, ERR_INVALID_PARAMETER);
+
+	int family = p_type == IP_Address::TYPE_IPV4 ? AF_INET : AF_INET6;
+	int sockfd = socket(family, type, protocol);
+
+	ERR_FAIL_COND_V( sockfd == -1, -1 );
+
+	if(family == AF_INET6) {
+		// Ensure IPv4 over IPv6 is enabled
+		int v6_only = 0;
+		if(setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&v6_only, sizeof(v6_only)) != 0) {
+			WARN_PRINT("Unable to set IPv4 address mapping over IPv6");
+		}
+	}
+
+	return sockfd;
+}
+
+
 static void _set_ip_addr_port(IP_Address& r_ip, int& r_port, struct sockaddr_storage* p_addr) {
 
 	if (p_addr->ss_family == AF_INET) {

drivers/unix/stream_peer_tcp_posix.cpp

@@ -137,8 +137,8 @@ Error StreamPeerTCPPosix::connect(const IP_Address& p_host, uint16_t p_port) {
 
 	ERR_FAIL_COND_V( p_host.type == IP_Address::TYPE_NONE, ERR_INVALID_PARAMETER);
 
-	int family = p_host.type == IP_Address::TYPE_IPV6 ? AF_INET6 : AF_INET;
-	if ((sockfd = socket(family, SOCK_STREAM, 0)) == -1) {
+	sockfd = _socket_create(p_host.type, SOCK_STREAM, IPPROTO_TCP);
+	if (sockfd == -1) {
 		ERR_PRINT("Socket creation failed!");
 		disconnect();
 		//perror("socket");

drivers/unix/tcp_server_posix.cpp

@@ -71,8 +71,8 @@ void TCPServerPosix::make_default() {
 Error TCPServerPosix::listen(uint16_t p_port, IP_Address::AddrType p_type, const List<String> *p_accepted_hosts) {
 
 	int sockfd;
-	int family = p_type == IP_Address::TYPE_IPV6 ? AF_INET6 : AF_INET;
-	sockfd = socket(family, SOCK_STREAM, 0);
+	sockfd = _socket_create(p_type, SOCK_STREAM, IPPROTO_TCP);
+
 	ERR_FAIL_COND_V(sockfd == -1, FAILED);
 #ifndef NO_FCNTL
 	fcntl(sockfd, F_SETFL, O_NONBLOCK);

platform/windows/packet_peer_udp_winsock.cpp

@@ -239,11 +239,7 @@ int PacketPeerUDPWinsock::_get_socket(IP_Address::AddrType p_type) {
 	if (sockfd != -1)
 		return sockfd;
 
-	int family = p_type == IP_Address::TYPE_IPV6 ? AF_INET6 : AF_INET;
-
-	sockfd = socket(family, SOCK_DGRAM, IPPROTO_UDP);
-	ERR_FAIL_COND_V( sockfd == -1, -1 );
-	//fcntl(sockfd, F_SETFL, O_NONBLOCK);
+	sockfd = _socket_create(p_type, SOCK_DGRAM, IPPROTO_UDP);
 
 	return sockfd;
 }

platform/windows/stream_peer_winsock.cpp

@@ -296,8 +296,8 @@ Error StreamPeerWinsock::connect(const IP_Address& p_host, uint16_t p_port) {
 
 	ERR_FAIL_COND_V( p_host.type == IP_Address::TYPE_NONE, ERR_INVALID_PARAMETER);
 
-	int family = p_host.type == IP_Address::TYPE_IPV6 ? AF_INET6 : AF_INET;
-	if ((sockfd = socket(family, SOCK_STREAM, IPPROTO_TCP)) == INVALID_SOCKET) {
+	sockfd = _socket_create(p_host.type, SOCK_STREAM, IPPROTO_TCP);
+	if (sockfd  == INVALID_SOCKET) {
 		ERR_PRINT("Socket creation failed!");
 		disconnect();
 		//perror("socket");

platform/windows/tcp_server_winsock.cpp

@@ -66,7 +66,7 @@ void TCPServerWinsock::cleanup() {
 Error TCPServerWinsock::listen(uint16_t p_port, IP_Address::AddrType p_type,const List<String> *p_accepted_hosts) {
 
 	int sockfd;
-	sockfd = socket(AF_INET, SOCK_STREAM, 0);
+	sockfd = _socket_create(p_type, SOCK_STREAM, IPPROTO_TCP);
 	ERR_FAIL_COND_V(sockfd == INVALID_SOCKET, FAILED);
 
 	unsigned long par = 1;