编译完了是一个基于串口PPP接入程序，用户拨号成功后，产生一个PPP服务进程，其他进程或内核可以向该进程发送数据包，在此基础上可以做数据链路加密的服务-end of a compiler based on the Serial PPP access, users dial-up after the success of PPP services have a process, or other processes to process core can send data packets, th