python实现简单tftp(基于udp协议)

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()

#!/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

#!/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