mirror of
https://github.com/chocolate-doom/master-server.git
synced 2024-11-27 22:52:06 +00:00
113 lines
3 KiB
Python
Executable file
113 lines
3 KiB
Python
Executable file
#!/usr/bin/env python
|
|
#
|
|
# Copyright(C) 2010 Simon Howard
|
|
#
|
|
# This program is free software; you can redistribute it and/or
|
|
# modify it under the terms of the GNU General Public License
|
|
# as published by the Free Software Foundation; either version 2
|
|
# of the License, or (at your option) any later version.
|
|
#
|
|
# This program is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with this program; if not, write to the Free Software
|
|
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
|
|
# 02111-1307, USA.
|
|
#
|
|
#
|
|
# Cronjob script that checks the master server is running.
|
|
#
|
|
|
|
import socket
|
|
import sys
|
|
import struct
|
|
from select import select
|
|
from time import time
|
|
|
|
NET_MASTER_PACKET_TYPE_ADD = 0
|
|
NET_MASTER_PACKET_TYPE_ADD_RESPONSE = 1
|
|
NET_MASTER_PACKET_TYPE_QUERY = 2
|
|
NET_MASTER_PACKET_TYPE_QUERY_RESPONSE = 3
|
|
|
|
QUERY_ATTEMPTS = 5
|
|
|
|
MASTER_SERVER = "master.chocolate-doom.org"
|
|
UDP_PORT = 2342
|
|
|
|
def send_message(sock, addr, message_type, payload=None):
|
|
header = struct.pack(">h", message_type)
|
|
packet = header
|
|
|
|
if payload is not None:
|
|
packet += payload
|
|
|
|
sock.sendto(packet, addr)
|
|
|
|
def get_response(sock, addr, expected_type, timeout):
|
|
""" Wait for a response packet to be received. """
|
|
|
|
start_time = time()
|
|
|
|
while time() - start_time < timeout:
|
|
r, w, x = select([sock], [], [], 1)
|
|
|
|
if sock in r:
|
|
packet, remote_addr = sock.recvfrom(1024)
|
|
|
|
type, = struct.unpack(">h", packet[0:2])
|
|
|
|
if expected_type == type:
|
|
return type, packet[2:]
|
|
|
|
raise Exception("No response received from server in %i seconds"
|
|
% (time() - start_time))
|
|
|
|
def read_string(packet):
|
|
terminator = struct.pack("b", 0)
|
|
strlen = packet.index(terminator)
|
|
|
|
result = struct.unpack("%ss" % strlen, packet[0:strlen])
|
|
|
|
return packet[strlen + 1:], result
|
|
|
|
def parse_query_response(packet):
|
|
servers = []
|
|
|
|
while len(packet) > 0:
|
|
packet, addr_str = read_string(packet)
|
|
|
|
servers.append(addr_str)
|
|
|
|
return servers
|
|
|
|
def query_master(addr_str):
|
|
""" Query a master server for its list of server IP addresses. """
|
|
|
|
addr = (socket.gethostbyname(addr_str), UDP_PORT)
|
|
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
|
|
|
|
send_message(sock, addr, NET_MASTER_PACKET_TYPE_QUERY)
|
|
|
|
type, response = get_response(sock, addr,
|
|
NET_MASTER_PACKET_TYPE_QUERY_RESPONSE,
|
|
5)
|
|
|
|
servers = parse_query_response(response)
|
|
|
|
# Try several times, as there might be packet loss.
|
|
|
|
failures = 0
|
|
|
|
while failures < QUERY_ATTEMPTS:
|
|
try:
|
|
query_master(MASTER_SERVER)
|
|
break
|
|
except:
|
|
failures += 1
|
|
else:
|
|
sys.stderr.write("No response from master server after %i attempts.\n"
|
|
% failures)
|
|
|