package main

import (
	"fmt"
	"net"
	"strings"
	"sync"
)

type List struct {
	Lock   sync.Mutex
	IPList map[string]bool
}

var CheckList *List = NewList()

func main() {
	for _,k := range []string{"127.0.0.1","192.168.10.1","172.18.80.1"} {
		CheckList.Add(k)
	}
	conn,_ := net.Dial("tcp","127.0.0.1:1789")
	if !CheckList.IsExist(conn) {
		fmt.Println("没有在白名单")
		conn.Close()
		return
	}
}

func NewList() *List {
	return &List{IPList: make(map[string]bool)}

}

func (self *List) Add(s string) {
	if self.IPList[s] {
		return
	}
	self.Lock.Lock()
	self.IPList[s] = true
	self.Lock.Unlock()
}
func (self *List) IsExist(conn net.Conn) bool {
	ip := strings.Split(conn.RemoteAddr().String(),":")[0]
	return self.IPList[ip]
}