python实现简单tftp(基于udp协议)-创新互联
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() 分享题目:python实现简单tftp(基于udp协议)-创新互联
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