<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def validate_node(self, node_ip, node_port=None, same_nodes=1):

 self.debug_print("Validating: " + node_ip)
 
 # Is this a valid IP?
 if not is_ip_valid(node_ip) or node_ip == "0.0.0.0":
 self.debug_print("Invalid node ip in validate node")
 return 0
 
 # Is this a valid port?
 if node_port != 0 and node_port is not None:
 if not is_valid_port(node_port):

 self.debug_print("Invalid node port in validate port")
 return 0
 
 """
 Don't accept connections from self to passive server
 or connections to already connected nodes.
 """

        if not self.enable_duplicate_ip_cons:
            # Don't connect to ourself.
            if (node_ip == "127.0.0.1" or
                    node_ip == get_lan_ip(self.interface) or
                    node_ip == self.wan_ip):
                self.debug_print("Cannot connect to ourself.")
                return 0

            # No, really: don't connect to ourself.
            if node_ip == self.passive_bind and node_port == self.passive_port:
                self.debug_print("Error connecting to same listen server.")
                return 0

            # Don't connect to same nodes.
            if same_nodes:
                for node in self.outbound + self.inbound:
                    try:
                        addr, port = node["con"].s.getpeername()
                        if node_ip == addr:
                            self.debug_print("Already connected to this node.")
                            return 0
                    except Exception as e:
                        print(e)
                        return 0

        return 1