GoBackN协议的C语言实现

模仿数据链路层的gobackn协议 /*该协议是搭载ack的回退n步协议*/ #include <stdio.h> #include "protocol.h" #define max_seq 7 #define flag 126 #define ESC 100 #define wait_time 2700 //发送计时器等待的时间 #define ack_wait_time 280 static int phl_ready = 0; unsigned char buf[max_seq+1][270]; unsigned char ack[8]; //发送空的ack帧