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from socket import *
import time, select, sys
from errno import ETIMEDOUT
UDP_PORT = 8056
PING_MESSAGE = b"pclient-game-ping"
PONG_MESSAGE = b"server-game-pong"
def serverside_ping(only_port=None):
port = only_port or UDP_PORT
s = socket(AF_INET, SOCK_DGRAM)
try:
s.bind(('', port))
s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
return s
except error as e:
if only_port is None:
s = socket(AF_INET, SOCK_DGRAM)
s.bind(('', INADDR_ANY))
return s
else:
return None
def answer_ping(s, descr, addr, extra='', httpport=''):
try:
data, source = s.recvfrom(100)
except error as e:
print('ping error:', str(e), file=sys.stderr)
return
if data == PING_MESSAGE:
print("ping by", source, file=sys.stderr)
answer = '%s:%s:%s:%s:%s:%s' % (PONG_MESSAGE, descr,
addr[0], addr[1], extra, httpport)
s.sendto(answer.encode(), source)
else:
print("unexpected data on UDP port %d by" % UDP_PORT, source, file=sys.stderr)
def pick(hostlist, delay=1):
s = socket(AF_INET, SOCK_DGRAM)
s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
for host in hostlist:
print("* Looking for a server on %s... " % host, file=sys.stderr)
try:
s.sendto(PING_MESSAGE, (host, UDP_PORT))
except error as e:
print('send:', str(e), file=sys.stderr)
continue
while 1:
iwtd, owtd, ewtd = select.select([s], [], [], delay)
if not iwtd:
break
try:
data, answer_from = s.recvfrom(200)
except error as e:
if e.args[0] != ETIMEDOUT:
print('recv:', str(e), file=sys.stderr)
continue
break
data = data.split(':')
if len(data) >= 4 and data[0] == PONG_MESSAGE:
hostname = data[2] or answer_from[0]
try:
port = int(data[3])
except ValueError:
pass
else:
result = (hostname, port)
print("* Picking %r at" % data[1], result, file=sys.stderr)
return result
print("got an unexpected answer", data, "from", answer_from, file=sys.stderr)
print("no server found.", file=sys.stderr)
raise SystemExit
def find_servers(hostlist=[('127.0.0.1', None), ('<broadcast>', None)],
tries=2, delay=0.5, verbose=1, port_needed=1):
import gamesrv
if verbose:
print('Looking for servers in the following list:', file=sys.stderr)
for host, udpport in hostlist:
print(' %s, UDP port %s' % (
host, udpport or ("%s (default)" % UDP_PORT)), file=sys.stderr)
events = {}
replies = []
s = socket(AF_INET, SOCK_DGRAM)
s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
for trynum in range(tries):
for host, udpport in hostlist:
try:
ipaddr = host
if host != '<broadcast>':
try:
ipaddr = gethostbyname(host)
except error as e:
print('gethostbyname:', str(e), file=sys.stderr)
s.sendto(PING_MESSAGE, (ipaddr, udpport or UDP_PORT))
hostsend, hostrecv = events.setdefault(ipaddr, ([], []))
hostsend.append(time.time())
except error as e:
print('send:', str(e), file=sys.stderr)
continue
endtime = time.time() + delay
while gamesrv.recursiveloop(endtime, [s]):
try:
data, answer_from = s.recvfrom(200)
except error as e:
if e.args[0] != ETIMEDOUT:
print('recv:', str(e), file=sys.stderr)
continue
break
try:
ipaddr = gethostbyname(answer_from[0])
except error:
ipaddr = answer_from[0]
else:
hostsend, hostrecv = events.setdefault(ipaddr, ([], []))
hostrecv.append(time.time())
data = data.split(b':')
if len(data) >= 4 and data[0] == PONG_MESSAGE:
try:
port = int(data[3])
except ValueError:
if port_needed:
continue
port = ''
if data[2]:
hostname = data[2]
realhostname = [hostname]
else:
hostname = answer_from[0]
realhostname = lazy_gethostbyaddr(hostname)
server = ':'.join(data[1:2]+data[4:])
replies.append((hostname, realhostname, port, server, ipaddr))
else:
print("got an unexpected answer from", answer_from, file=sys.stderr)
servers = {}
aliases = {}
timeout = time.time() + 2.0 # wait for gethostbyaddr() for 2 seconds
while replies:
i = 0
now = time.time()
while i < len(replies):
hostname, realhostname, port, server, ipaddr = replies[i]
if realhostname:
hostname = realhostname[0] # got an answer
elif now < timeout:
i += 1 # must wait some more time
continue
result = (hostname, port)
servers[result] = server
aliases[hostname] = ipaddr
del replies[i]
if replies:
time.sleep(0.08) # time for gethostbyaddr() to finish
if verbose:
print("%d answer(s):" % len(servers), list(servers.keys()), file=sys.stderr)
for host, port in list(servers.keys()):
ping = None
ipaddr = aliases[host]
if ipaddr in events:
hostsend, hostrecv = events[ipaddr]
if len(hostsend) == len(hostrecv) == tries:
ping = min([t2-t1 for t1, t2 in zip(hostsend, hostrecv)])
servers[host, port] = (servers[host, port], ping)
sys.setcheckinterval(4096)
return servers
# ____________________________________________________________
HOSTNAMECACHE = {}
def _lazygetter(hostname, resultlst):
try:
try:
hostname = gethostbyaddr(hostname)[0]
if hostname == 'localhost':
from .msgstruct import HOSTNAME as hostname
except error:
pass
finally:
resultlst.append(hostname)
def lazy_gethostbyaddr(hostname):
try:
return HOSTNAMECACHE[hostname]
except KeyError:
resultlst = HOSTNAMECACHE[hostname] = []
import _thread
_thread.start_new_thread(_lazygetter, (hostname, resultlst))
return resultlst
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