todo

实现了ipv6到ipv4的转换（部分实现）

Here's a rough list of things that may make this better:

(- means it still needs to be done, + means it has been done)

- Read config from file, not just command line
- Once using a config file, have multiple listeners and stuff all come up at once
- Some kind of TCP Wrappers with rules from config file
+ Daemonize
+ Switch to non-root user once bound to low port number