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ns_server.py
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ns_server.py
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import socket
import sys
import struct
import ctypes
FILTER=''.join([(len(repr(chr(x)))==3) and chr(x) or '.' for x in range(256)])
def dump(src, length=8):
N=0; result=''
while src:
s,src = src[:length],src[length:]
hexa = ' '.join(["%02X"%ord(x) for x in s])
s = s.translate(FILTER)
result += "%04X %-*s %s\n" % (N, length*3, hexa, s)
N+=length
return result
peers = int(sys.argv[1])
port = 0
if len(sys.argv) > 2 and sys.argv[2]:
port = int(sys.argv[2])
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(('', port))
print s.getsockname()[1]
bind_map = {}
conn_map = {}
peer_map = {}
while 1:
try:
message, address = s.recvfrom(65535)
print dump(message)
offset = 0
alias = struct.unpack_from('!I', message, offset)[0]
print '%08x = %s:%d' % (alias, address[0], address[1])
offset += 4
count = struct.unpack_from('!I', message, offset)[0]
offset += 4
for i in range(count):
h, _junk, port = struct.unpack_from('!IIH', message, offset)[0:3]
bind_map.setdefault(alias, {})[h] = port
print '%08x:%d <- %08x' % (alias, port, h)
offset += 10
conn_map[alias] = ctypes.create_string_buffer(message[offset:])
peer_map.setdefault(alias, {})[0] = address[0]
peer_map.setdefault(alias, {})[1] = address[1]
if len(peer_map) == peers:
for src in peer_map.iterkeys():
reply = conn_map[src]
offset = 0
count = struct.unpack_from('!I', reply, offset)[0]
offset += 4
log = ''
for i in range(count):
h = struct.unpack_from('!I', reply, offset)[0]
port = bind_map[h][src]
struct.pack_into('!4sH', reply, offset + 4, socket.inet_pton(socket.AF_INET, peer_map[h][0]), port)
log += str([peer_map[h][0], port])
offset += 10
s.sendto(reply, (peer_map[src][0], peer_map[src][1]))
print ['sending to: ', peer_map[src][0], peer_map[src][1], log]
except (KeyboardInterrupt, SystemExit):
exit(1)