Posted in Python onJuly 30, 2018
本文实例为大家分享了python实现简单tftp的具体代码,供大家参考,具体内容如下
- tftp是基于udp的协议
- 实现简单的tftp,首先要有tftp的协议图。
- tftp默认接收端口为69,但每次有连接过来后,tftp会随机分配一个端口来专门为这个连接来服务。
- 操作码:1.上传 2.下载 3.传数据 4.接收确认 5.错误码
tftp服务器简单实现:
from threading import Thread from socket import * import struct def upload(filename,user_ip,user_port): num = 0 f = open(filename,'ab') s_up = socket(AF_INET,SOCK_DGRAM) send_data_1 = struct.pack("!HH",4,num) s_up.sendto(send_data_1,(user_ip,user_port)) #第一次用随机端口发送 while True: recv_data,user_info = s_up.recvfrom(1024) #第二次客户连接我随机端口 caozuohao_up,ack_num = struct.unpack('!HH',recv_data[:4]) print(caozuohao_up,ack_num,num) if int(caozuohao_up) == 3 and ack_num == num : f.write(recv_data[4:]) send_data = struct.pack("!HH",4,num) s_up.sendto(send_data,(user_ip,user_port)) #第二次我用随机端口发 num = num + 1 if len(recv_data) < 516: print(user_ip+'上传文件'+filename+':完成') f.close() exit() def download(filename,user_ip,user_port): s_down = socket(AF_INET, SOCK_DGRAM) num = 0 try: f = open(filename,'rb') except: error_data = struct.pack('!HHHb',5,5,5,num) s_down.sendto(error_data, (user_ip,user_port)) #文件不存在时发送 exit() #只会退出此线程 while True: read_data = f.read(512) send_data = struct.pack('!HH',3,num) + read_data s_down.sendto(send_data, (user_ip,user_port)) #数据第一次发送 if len(read_data) < 512: print('传输完成, 对方下载成功') exit() recv_ack = s_down.recv(1024) #第二次接收 caozuoma,ack_num = struct.unpack("!HH", recv_ack) # print(caozuoma,ack_num,len(read_data)) num += 1 if int(caozuoma) != 4 or int(ack_num) != num-1 : exit() f.close() s = socket(AF_INET,SOCK_DGRAM) s.bind(('',69)) def main(): while 1: recv_data,(user_ip,user_port) = s.recvfrom(1024) #第一次客户连接69端口 print(recv_data, user_ip, user_port) if struct.unpack('!b5sb',recv_data[-7:]) == (0, b'octet', 0): caozuoma = struct.unpack('!H',recv_data[:2]) filename = recv_data[2:-7].decode('gb2312') if caozuoma[0] == 1: print('对方想下载数据',filename) t = Thread(target = download, args = (filename,user_ip,user_port)) t.start() elif caozuoma[0] == 2: print('对方想上传数据',filename) t = Thread(target = upload, args = (filename,user_ip,user_port)) t.start() if __name__ == '__main__': main()
上传数据简单实现:
#!/usr/bin/env python3 #coding=utf-8 import struct from socket import * server_ip = '192.168.119.157' send_data_1 = struct.pack('!H8sb5sb',2,'王辉.jpg'.encode('gb2312'),0,b'octet',0) s = socket(AF_INET,SOCK_DGRAM) s.sendto(send_data_1,(server_ip,69)) #第一次发给服务器69端口 f = open('王辉.jpg','rb') recv_data = s.recvfrom(1024) #第一次接收数据 rand_port = recv_data[1][1] print() ack_num = struct.unpack("!HH",recv_data[0][:4]) num = 0 while True: read_data = f.read(512) send_data = struct.pack('!HH',3,num) + read_data s.sendto(send_data,(server_ip,rand_port)) #第二次发给服务器的随机端口 recv_data_2,userinfo = s.recvfrom(1024) print(recv_data_2) ack_num = struct.unpack('!H',recv_data_2[2:4]) print(len(read_data),num,ack_num[0],rand_port) if len(read_data) < 512 or ack_num[0] != num : break num = num + 1
下载数据简单实现:
#!/usr/bin/env python3 #coding=utf-8 import struct from socket import * filename = 'test.jpg' server_ip = '192.168.1.113' send_data = struct.pack('!H%dsb5sb'%len(filename),1,filename.encode('gb2312'),0,'octet'.encode('gb2312'),0) s = socket(AF_INET,SOCK_DGRAM) s.sendto(send_data,(server_ip,69)) #第一次发送, 连接服务器69端口 f = open(filename,'ab') while 1: recv_data = s.recvfrom(1024) #接收数据 caozuoma,ack_num = struct.unpack('!HH',recv_data[0][:4]) #获取数据块编号 rand_port = recv_data[1][1] #获取服务器的随机端口 if int(caozuoma) == 5: print('服务器返回: 文件不存在...') break print(caozuoma,ack_num,rand_port,len(recv_data[0])) f.write(recv_data[0][4:]) if len(recv_data[0]) < 516: break ack_data = struct.pack("!HH",4,ack_num) s.sendto(ack_data,(server_ip,rand_port)) #回复ACK确认包
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持三水点靠木。
python实现简单tftp(基于udp协议)
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Erick-LONG声明:登载此文出于传递更多信息之目的,并不意味着赞同其观点或证实其描述。
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