pymaster: implement server-to-master challenge, implement ratelimiting, remove server remove handler it can be broken with IP spoofing, refactoring
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3cbb519ccb
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232
pymaster.py
232
pymaster.py
@ -6,103 +6,157 @@ import traceback
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import logging
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import os
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from optparse import OptionParser
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from struct import pack
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from struct import pack, unpack
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from time import time
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from ipaddress import ip_address, ip_network
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from server_entry import ServerEntry
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from protocol import MasterProtocol
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import ipfilter
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LOG_FILENAME = 'pymaster.log'
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MAX_SERVERS_FOR_IP = 14
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CHALLENGE_SEND_PERIOD = 10
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def logPrint( msg ):
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logging.debug( msg )
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def log(msg):
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logging.debug(msg)
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class RateLimitItem:
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def __init__(self, resetAt):
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self.reset(resetAt)
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def reset(self, resetAt):
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self.resetAt = resetAt
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self.logs = self.calls = 0
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def inc(self):
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self.calls = self.calls + 1
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self.logs = self.logs + 1
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def shouldReset(self, curtime):
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return curtime > self.resetAt
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class IPRateLimit:
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def __init__(self, type, period, maxcalls):
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self.type = type
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self.period = period
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self.maxcalls = maxcalls
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self.maxlogs = maxcalls + 2
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self.ips = {}
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def ratelimit(self, ip):
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curtime = time()
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if ip not in self.ips:
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self.ips[ip] = RateLimitItem(curtime + self.period)
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elif self.ips[ip].shouldReset(curtime):
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self.ips[ip].reset(curtime + self.period)
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self.ips[ip].inc()
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if self.ips[ip].calls > self.maxcalls:
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if self.ips[ip].logs < self.maxlogs:
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log('Ratelimited %s %s' % (self.type, ip))
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return True
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return False
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class PyMaster:
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def __init__(self, ip, port):
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self.serverList = []
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self.sock = socket.socket( socket.AF_INET, socket.SOCK_DGRAM )
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self.sock.bind( (ip, port) )
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self.serverRL = IPRateLimit('server', 60, 30)
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self.clientRL = IPRateLimit('client', 60, 120)
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self.ipfilterRL = IPRateLimit('filterlog', 60, 10)
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self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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self.sock.bind((ip, port))
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logPrint("Welcome to PyMaster!")
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logPrint("I ask you again, are you my master?")
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logPrint("Running on %s:%d" % (ip, port))
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log("Welcome to PyMaster!")
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log("I ask you again, are you my master?")
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log("Running on %s:%d" % (ip, port))
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def serverLoop(self):
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data, addr = self.sock.recvfrom(1024)
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data = data.decode('latin_1')
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if( data[0] == MasterProtocol.clientQuery ):
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self.clientQuery(data, addr)
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elif( data[0] == MasterProtocol.challengeRequest ):
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self.sendChallengeToServer(data, addr)
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elif( data[0] == MasterProtocol.addServer ):
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self.addServerToList(data, addr)
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elif( data[0] == MasterProtocol.removeServer ):
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self.removeServerFromList(data, addr)
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else:
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logPrint("Unknown message: {0} from {1}:{2}".format(data, addr[0], addr[1]))
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def clientQuery(self, data, addr):
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region = data[1] # UNUSED
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data = data.strip('1' + region)
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try:
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query = data.split('\0')
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except ValueError:
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logPrint(traceback.format_exc())
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if ip_address(addr[0]) in ipfilter.ipfilter:
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if not self.ipfilterRL.ratelimit(addr[0]):
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log('Filter: %s:%d' % (addr[0], addr[1]))
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return
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queryAddr = query[0] # UNUSED
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rawFilter = query[1]
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if len(data) == 0:
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return
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# Remove first \ character
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rawFilter = rawFilter.strip('\\')
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split = rawFilter.split('\\')
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# only client stuff
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if data.startswith(MasterProtocol.clientQuery):
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if not self.clientRL.ratelimit(addr[0]):
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self.clientQuery(data, addr)
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return
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# Use NoneType as undefined
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gamedir = 'valve' # halflife, by default
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clver = None
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nat = 0
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# only server stuff
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if not self.serverRL.ratelimit(addr[0]):
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if data.startswith(MasterProtocol.challengeRequest):
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self.sendChallengeToServer(data, addr)
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elif data.startswith(MasterProtocol.addServer):
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self.addServerToList(data, addr)
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elif data.startswith(MasterProtocol.removeServer):
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self.removeServerFromList(data, addr)
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else:
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log('Unknown message: %s from %s:%d' % (str(data), addr[0], addr[1]))
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for i in range( 0, len(split), 2 ):
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def clientQuery(self, data, addr):
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data = data.decode('latin_1')
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data = data.strip('1' + data[1])
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info = data.split('\0')[1].strip('\\')
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split = info.split('\\')
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protocol = None
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gamedir = 'valve'
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clver = None
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nat = 0
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for i in range(0, len(split), 2):
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try:
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key = split[i + 1]
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if( split[i] == 'gamedir' ):
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gamedir = key.lower() # keep gamedir in lowercase
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elif( split[i] == 'nat' ):
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nat = int(key)
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elif( split[i] == 'clver' ):
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clver = key
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k = split[i]
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v = split[i + 1]
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if k == 'gamedir':
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gamedir = v.lower() # keep gamedir in lowercase
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elif k == 'nat':
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nat = int(v)
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elif k == 'clver':
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clver = v
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elif k == 'protocol':
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protocol = int(v)
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# somebody is playing :)
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elif k == 'thisismypcid' or k == 'heydevelopersifyoureadthis':
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self.fakeInfoForOldVersions(gamedir, addr)
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return
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else:
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logPrint('Unhandled info string entry: {0}/{1}. Infostring was: {2}'.format(split[i], key, split))
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log('Client Query: %s:%d, invalid infostring=%s' % (addr[0], addr[1], rawFilter))
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except IndexError:
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pass
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if( clver == None ): # Probably an old vulnerable version
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self.fakeInfoForOldVersions( gamedir, addr )
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self.fakeInfoForOldVersions(gamedir, addr)
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return
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packet = MasterProtocol.queryPacketHeader
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for i in self.serverList:
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if( time() > i.die ):
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if time() > i.die:
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self.serverList.remove(i)
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continue
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if( not i.check ):
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if not i.check:
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continue
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if( nat != i.nat ):
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if nat != i.nat or gamedir != i.gamedir:
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continue
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if( gamedir != None ):
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if( gamedir != i.gamedir ):
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continue
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if protocol != None and protocol != i.protocol:
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continue
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if( nat ):
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reply = '\xff\xff\xff\xffc {0}:{1}'.format( addr[0], addr[1] )
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data = reply.encode( 'latin_1' )
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if nat:
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# Tell server to send info reply
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self.sock.sendto( data, i.addr )
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data = ('\xff\xff\xff\xffc %s:%d' % (addr[0], addr[1])).encode('latin_1')
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self.sock.sendto(data, i.addr)
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# Use pregenerated address string
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packet += i.queryAddr
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@ -124,53 +178,65 @@ class PyMaster:
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sendFakeInfo(self.sock, "GooglePlay или GitHub", gamedir, addr)
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def removeServerFromList(self, data, addr):
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for i in self.serverList:
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if (i.addr == addr):
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logPrint("Remove Server: from {0}:{1}".format(addr[0], addr[1]))
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self.serverList.remove(i)
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pass
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def sendChallengeToServer(self, data, addr):
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logPrint("Challenge Request: from {0}:{1}".format(addr[0], addr[1]))
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# At first, remove old server- data from list
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#self.removeServerFromList(None, addr)
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count = 0
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s = None
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for i in self.serverList:
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if ( i.addr[0] == addr[0] ):
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if( i.addr[1] == addr[1] ):
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self.serverList.remove(i)
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else:
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count += 1
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if( count > MAX_SERVERS_FOR_IP ):
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if addr[0] != i.addr[0]:
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continue
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if addr[1] == i.addr[1]:
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s = i
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break
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else:
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count += 1
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if count > MAX_SERVERS_FOR_IP:
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return
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# Generate a 32 bit challenge number
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challenge = random.randint(0, 2**32-1)
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challenge2 = None
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if len(data) == 6:
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# little endian challenge
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challenge2 = unpack('<I', data[2:])[0]
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# Add server to list
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self.serverList.append(ServerEntry(addr, challenge))
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if not s:
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challenge = random.randint(0, 2**32-1) & 0xffffffff #hash(addr[0]) + hash(addr[1]) + hash(time())
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s = ServerEntry(addr, challenge)
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self.serverList.append(s)
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elif s.sentChallengeAt + 5 > time():
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return
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# And send him a challenge
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packet = MasterProtocol.challengePacketHeader
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packet += pack('I', challenge)
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packet += pack('I', s.challenge)
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# send server-to-master challenge back
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if challenge2 is not None:
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packet += pack('I', challenge2)
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self.sock.sendto(packet, addr)
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def addServerToList(self, data, addr):
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logPrint("Add Server: from {0}:{1}".format(addr[0], addr[1]))
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# Remove the header. Just for better parsing.
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serverInfo = data.strip('\x30\x0a\x5c')
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info = data.strip(b'\x30\x0a\x5c').decode('latin_1')
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# Find a server with same address
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for serverEntry in self.serverList:
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if( serverEntry.addr == addr ):
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s = None
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for s in self.serverList:
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if s.addr == addr:
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break
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if not s:
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log('Server skipped challenge request: %s:%d' % (addr[0], addr[1]))
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return
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serverEntry.setInfoString( serverInfo )
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if s.setInfoString( info ):
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log('Add server: %s:%d, game=%s/%s, protocol=%d, players=%d/%d/%d, version=%s' % (addr[0], addr[1], s.gamemap, s.gamedir, s.protocol, s.players, s.bots, s.maxplayers, s.version))
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else:
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log('Failed challenge from %s:%d: %d must be %d' % (addr[0], addr[1], s.challenge, s.challenge2))
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def spawn_pymaster(verbose, ip, port):
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if verbose:
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logging.getLogger().addHandler(logging.StreamHandler())
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logging.getLogger().addHandler(logging.FileHandler(LOG_FILENAME))
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# logging.getLogger().addHandler(logging.FileHandler(LOG_FILENAME))
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logging.getLogger().setLevel(logging.DEBUG)
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masterMain = PyMaster(ip, port)
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@ -178,7 +244,7 @@ def spawn_pymaster(verbose, ip, port):
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try:
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masterMain.serverLoop()
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except Exception:
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logPrint(traceback.format_exc())
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log(traceback.format_exc())
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pass
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if __name__ == "__main__":
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