BitTorrent UDP Tracker 响应

Question

我对UDP公告响应是如何处理的有些疑问，这在bep UDP协议规范中有提到。

import socket,struct
clisocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
connection_id=0x41727101980
transaction_id = 12345

# responses Tracker : Specification  UDP [ User Datagaram Protocol ]
info_hash  = "%1D%D4%D1%EDQn%DB%5CL%83%90%1B%2B%F8%83%A2%19%C0%7C%98"
peer_id = "-UT1234-m%09%B2%D5%99%FA%1Fj%88%AC%0D%A7"
action =1 # announce
downloaded = 0
left = 0
uploaded = 0
event =0
ip = 0
key = 0
num_want = -1
port = 9999

announce_pack = struct.pack(">QLL20s20sQQQLLLLH",connection_id,action,transaction_id,info_hash,peer_id,down  loaded,left,uploaded,event,ip,key,num_want,port)
clisocket.sendto(announce_pack, ("tracker.ccc.de", 80))
res = clisocket.recv(1024)
action=struct.unpack(">HLLLLQQQ20s20sLLQ",res)

但是我遇到了以下错误。

DeprecationWarning: struct integer overflow masking is deprecated announce_pack=struct.pack(">QLL20s20sQQQLLLLH",connection_id,action,transaction_id,info_hash,peer_id,downloaded,left,uploaded,event,ip,key,num_want,port)
Traceback (most recent call last):
action=struct.unpack(">HLLLLQQQ20s20sLLQ",res)
struct.error: unpack requires a string argument of length 98

Answer 1

看起来你传给结构体的字符串太大了，可能是因为你收到了多个数据包。试试这个

action=struct.unpack(">HLLLLQQQ20s20sLLQ",res[:98])

另外，你似乎没有正确解析公告的响应。可以查看这里，了解UDP跟踪器数据包的格式。