BitTorrent-Client: Erste Peer-Liste von Trackers [Python]

Question

Ich versuche, die Peer-Liste von den Tracker zu bekommen https://wiki.theory.org/BitTorrent_Tracker_Protocol

mit Aber die meisten der Torrent-Dateien auf dem Netz verwenden ein udp Tracker. Die obige Website ist für HTTP-Tracker. Die Torrent-Dateien mit HTTP-basierte Tracker geben einen Fehler (Passkey error , or hash error or user error or 404 not found response)

Gerade jetzt mein Anforderungscode für alle HTTP-Tracker wie folgt aussehen:.

payload = urllib.urlencode(payload) 
     for ann in self.torrent.announce_list: 
      if("udp" not in ann[0]): 
       url = ann[0] 
       print "Encoded Request URL :",(url + "?" + payload) 
       print "Requesting Tracker for Peer List" 
       try: 
        response = urllib.urlopen(url + "?" + payload).read() 
        print "RESPONSE :",response 
       except Exception, e: 
        print e 

ich meine URL gegen die Anträge wird gemacht von uTorrent kreuzig haben mit Wireshark. Sie alle passen zusammen. Der Info-Hash wird korrekt generiert.

Wie kann ich die Peer-Liste von UDP sowie HTTP-Tracker abrufen? Ich versuche, keine externe Bibliothek wie lib-torrent zu verwenden. Eine Anleitung wäre wirklich hilfreich.

Answer 1

Der folgende Code funktionierte für mich. Aufruf von announce_udp() mit der Tracker-URL und dem Payload-Dictionary mit allen URL-Parametern.

import binascii, urllib, socket, random, struct 
from bcode import bdecode 
from urlparse import urlparse, urlunsplit 

def announce_udp(tracker,payload): 
    tracker = tracker.lower() 
    parsed = urlparse(tracker) 

    # Teporarly Change udp:// to http:// to get hostname and portnumbe 
    url = parsed.geturl()[3:] 
    url = "http" + url 
    hostname = urlparse(url).hostname 
    port = urlparse(url).port 


    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 
    sock.settimeout(8) 
    conn = (socket.gethostbyname(hostname), port) 
    #sock.bind((socket.gethostname(),s_port)) 

    #Get connection ID 
    req, transaction_id = udp_create_connection_request() 
    sock.sendto(req, conn); 
    buf = sock.recvfrom(2048)[0] 
    connection_id = udp_parse_connection_response(buf, transaction_id) 

    #Annoucing 
    s_port = sock.getsockname()[1] #get port number to which socket is connected 
    req, transaction_id = udp_create_announce_request(connection_id, payload,s_port) 
    sock.sendto(req, conn) 
    print "Announce Request Sent" 
    buf = sock.recvfrom(2048)[0] 
    print "Response received" 
    return udp_parse_announce_response(buf, transaction_id) 

def udp_create_announce_request(connection_id, payload, s_port): 
    action = 0x1 #action (1 = announce) 
    transaction_id = udp_get_transaction_id() 
    # print "2.Transaction ID :", transaction_id 
    buf = struct.pack("!q", connection_id)         #first 8 bytes is connection id 
    buf += struct.pack("!i", action)          #next 4 bytes is action 
    buf += struct.pack("!i", transaction_id)        #followed by 4 byte transaction id 
    buf += struct.pack("!20s", urllib.unquote(payload['info_hash']))  #the info hash of the torrent we announce ourselves in 
    buf += struct.pack("!20s", urllib.unquote(payload['peer_id']))   #the peer_id we announce 
    buf += struct.pack("!q", int(urllib.unquote(payload['downloaded']))) #number of bytes downloaded 
    buf += struct.pack("!q", int(urllib.unquote(payload['left'])))   #number of bytes left 
    buf += struct.pack("!q", int(urllib.unquote(payload['uploaded'])))  #number of bytes uploaded 
    buf += struct.pack("!i", 0x2)           #event 2 denotes start of downloading 
    buf += struct.pack("!i", 0x0)           #IP address set to 0. Response received to the sender of this packet 
    key = udp_get_transaction_id()           #Unique key randomized by client 
    buf += struct.pack("!i", key) 
    buf += struct.pack("!i", -1)           #Number of peers required. Set to -1 for default 
    buf += struct.pack("!i", s_port)          #port on which response will be sent 
    return (buf, transaction_id) 

def udp_parse_announce_response(buf, sent_transaction_id): 
    #print "Response is:"+str(buf) 
    if len(buf) < 20: 
     raise RuntimeError("Wrong response length while announcing: %s" % len(buf)) 
    action = struct.unpack_from("!i", buf)[0] #first 4 bytes is action 
    res_transaction_id = struct.unpack_from("!i", buf, 4)[0] #next 4 bytes is transaction id  
    if res_transaction_id != sent_transaction_id: 
     raise RuntimeError("Transaction ID doesnt match in announce response! Expected %s, got %s" 
      % (sent_transaction_id, res_transaction_id)) 
    print "Reading Response" 
    if action == 0x1: 
     print "Action is 3" 
     ret = dict() 
     offset = 8; #next 4 bytes after action is transaction_id, so data doesnt start till byte 8  
     ret['interval'] = struct.unpack_from("!i", buf, offset)[0] 
     print "Interval:"+str(ret['interval']) 
     offset += 4 
     ret['leeches'] = struct.unpack_from("!i", buf, offset)[0] 
     print "Leeches:"+str(ret['leeches']) 
     offset += 4 
     ret['seeds'] = struct.unpack_from("!i", buf, offset)[0] 
     print "Seeds:"+str(ret['seeds']) 
     offset += 4 
     peers = list() 
     x = 0 
     while offset != len(buf): 
      peers.append(dict()) 
      peers[x]['IP'] = struct.unpack_from("!i",buf,offset)[0] 
      print "IP: "+socket.inet_ntoa(struct.pack("!i",peers[x]['IP'])) 
      offset += 4 
      if offset >= len(buf): 
       raise RuntimeError("Error while reading peer port") 
      peers[x]['port'] = struct.unpack_from("!H",buf,offset)[0] 
      print "Port: "+str(peers[x]['port']) 
      offset += 2 
      x += 1 
     return ret,peers 
    else: 
     #an error occured, try and extract the error string 
     error = struct.unpack_from("!s", buf, 8) 
     print "Action="+str(action) 
     raise RuntimeError("Error while annoucing: %s" % error) 

def udp_create_connection_request(): 
    connection_id = 0x41727101980     #default connection id 
    action = 0x0         #action (0 = give me a new connection id) 
    transaction_id = udp_get_transaction_id() 
    print "1.Transaction ID :", transaction_id 
    buf = struct.pack("!q", connection_id)   #first 8 bytes is connection id 
    buf += struct.pack("!i", action)    #next 4 bytes is action 
    buf += struct.pack("!i", transaction_id)  #next 4 bytes is transaction id 
    return (buf, transaction_id) 

def udp_parse_connection_response(buf, sent_transaction_id): 
    if len(buf) < 16: 
     raise RuntimeError("Wrong response length getting connection id: %s" % len(buf))    
    action = struct.unpack_from("!i", buf)[0] #first 4 bytes is action 

    res_transaction_id = struct.unpack_from("!i", buf, 4)[0] #next 4 bytes is transaction id 
    if res_transaction_id != sent_transaction_id: 
     raise RuntimeError("Transaction ID doesnt match in connection response! Expected %s, got %s" 
      % (sent_transaction_id, res_transaction_id)) 

    if action == 0x0: 
     connection_id = struct.unpack_from("!q", buf, 8)[0] #unpack 8 bytes from byte 8, should be the connection_id 
     return connection_id 
    elif action == 0x3:  
     error = struct.unpack_from("!s", buf, 8) 
     raise RuntimeError("Error while trying to get a connection response: %s" % error) 
    pass 

def udp_get_transaction_id(): 
    return int(random.randrange(0, 255))