A simple regular-expression based DNS server, based on twisted.
hosts 文件里指定要劫持的域名，格式为：
#IP Domain
127.0.0.1 www.alipay.com
127.0.0.1 /.*?\.alipay\.com/
支持正则表达式，用/包围。
非劫持域名会向上级 DNS Server 递归查询，返回正确的 IP 地址。
Attacker(127.0.0.1):
sudo python dns.py
Target(127.0.0.1):
➜ ~ nslookup
> server 127.0.0.1
Default server: 127.0.0.1
Address: 127.0.0.1#53
> test.website
Server: 127.0.0.1
Address: 127.0.0.1#53
Non-authoritative answer:
Name: test.website
Address: 1.1.1.1
>
