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loadbalancerTCP.py
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loadbalancerTCP.py
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#!/usr/bin/env python
# -*- encoding: utf-8 -*-
import time
import struct
import socket
import asyncore, sys
import logging
from pytap import TapDevice
import netifaces
import re
regex_ipv4 = re.compile(r'^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$')
class Loadbalancer(asyncore.dispatcher):
out_buffer = []
def __init__(self, sock, control):
asyncore.dispatcher.__init__(self, sock)
if self.socket:
self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 8192)
# self.socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, True)
self.set_reuse_addr()
self.control = control
self.port = control.port
def initiate_send(self):
packet = self.out_buffer.pop() if len(self.out_buffer) else ''
logging.debug('Sending {}b packet to loadbalancing'.format(len(packet)))
while len(packet) > 0:
num_sent = asyncore.dispatcher.send(self, packet)
logging.debug('\t {}b sent'.format(num_sent))
if num_sent == 0:
break
packet = packet[num_sent:]
def writable(self):
return (not self.connected) or len(self.out_buffer)
def handle_read(self):
""" Everything read goes into the device """
data = self.recv(8192)
if data:
logging.debug('Reading {}b packet from loadbalancing'.format(len(data)))
self.control.write(data)
def send(self, data):
logging.debug('\tAdding {}b packet to buffer'.format(len(data)))
self.out_buffer.append(data)
self.initiate_send()
# NOTE: dispatcher already connects before send, when disconnected, right?
# def send(self, data):
# """ Wrap the builtin send with a reconnector """
# try:
# asyncore.dispatcher_with_send.send(self, data)
# except socket.error as e:
# if e.errno == 32:
# self.loadbalancer_connect()
# else:
# logging.exception("{} - Could not send data because: {}".format(self, e.strerror))
def handle_close(self):
""" Empty buffer and close """
self.out_buffer = []
self.close()
if self in self.control.loadbalancer_pool:
self.control.loadbalancer_pool.remove(self)
logging.info('{} Closed'.format(repr(self)))
def __repr__(self):
try:
return 'Loadbalancer:{}'.format(self.addr[-1])
except:
return 'Loadbalancer:<unbound>'
class LoadbalancerServer(Loadbalancer):
def handle_read(self):
""" Check for auth before first read """
data = self.recv(8192)
if data:
self.control.write(self.authorize(data))
def authorize(self, data):
""" Do authentication """
if data[:len(self.control.secret)] != self.control.secret:
self.send('403 unauthorized!')
self.close()
return
# If auth is successfull, replace with the normal read func
self.handle_read = lambda: Loadbalancer.handle_read(self)
return data[len(self.control.secret):]
class LoadbalancerClient(Loadbalancer):
def __init__(self, control, interface_spec):
sock = self.parse_interface_spec(interface_spec)
Loadbalancer.__init__(self, sock, control)
self.setup()
def authorize(self):
""" Do authentication """
self.send(self.control.secret)
def parse_interface_spec(self, interface_spec):
""" Parse interface_spec and make socket accordingly. """
# Test if there is an interface with that name
interfaces = netifaces.interfaces()
if ':' in interface_spec and interface_spec not in interfaces:
# So either ipv6 or interface/ipv4/ipv6:port
try:
socket.inet_pton(socket.AF_INET6, interface_spec)
ip_addr, port = interface_spec, 0
except socket.error:
# not ipv6, so interface/ipv4/ipv6:port
interface_name, port = interface_spec.split(':')
port = int(port)
try:
socket.inet_pton(socket.AF_INET6, interface_name)
ip_addr = interface_name
except socket.error:
# not ipv6, so ipv4 or interface-name
if re.match(regex_ipv4, interface_name):
ip_addr = interface_name
else:
ip_addr = get_ip_address(interface_name, self.socket)
else:
# ':' is not there or it is a subinterface/strange-name
port = 0
if re.match(regex_ipv4, interface_spec):
ip = interface_spec
else:
if_ = netifaces.ifaddresses(interface_spec)
# Find first address we can find (either v4 or v6)
for addr_family,addrs in if_.items():
for addr in addrs:
if 'addr' in addr:
ip_addr = addr['addr']
break
else:
logging.error('Cannot bind to specified interface "{}", has no address!'.format(interface_spec))
raise socket.error()
try:
socket.inet_pton(socket.AF_INET6, ip_addr)
sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
except:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self._addr = (ip_addr, port)
return sock
def setup(self):
""" Bind and connect """
self.loadbalancer_bind()
# Connect and authorize
self.connect((self.control.destination, self.control.port))
def loadbalancer_bind(self):
""" bind to the interface and the specified port (or random) """
try:
self.bind(self._addr)
logging.debug('Bound to {}:{}'.format(*self.addr))
except IOError as e:
logging.exception('Exception when binding loadbalancer to {}: |{}|'.format(repr(self._addr), e.strerror))
return
def handle_connect(self):
""" Authorize afterwards"""
self.authorize()
class LoadbalancerControl(asyncore.file_dispatcher):
shutdown = False # Loadbalancers shouldn't reconnect
rr = 0 # RoundRobin iterator counter
def __init__(self, options={}):
self.secret = options.get('secret','')
self.port = options.get('port',11111)
self.buffer = []
self.loadbalancer_pool = []
_tap = options.get('tap', True)
_name = options.get('name', '')
self.dev = TapDevice(tap=_tap, name=_name)
asyncore.file_dispatcher.__init__(self, self.dev.getFD())
self.dev.up()
if options.get('tunnel_address', False):
self.dev.ifconfig(address=options.get('tunnel_address'))
logging.debug('Interface ready')
def eth_addr (self, a) :
b = "%.2x:%.2x:%.2x:%.2x:%.2x:%.2x" % (ord(a[0]) , ord(a[1]) , ord(a[2]), ord(a[3]), ord(a[4]) , ord(a[5]))
return b
def validate(self, data):
eth_length = 14
eth_header = data[:eth_length]
eth = struct.unpack('!6s6sH' , eth_header)
eth_protocol = socket.ntohs(eth[2])
# print 'Destination MAC : ' + self.eth_addr(data[0:6]) + ' Source MAC : ' + self.eth_addr(data[6:12]) + ' Protocol : ' + str(eth_protocol)
ip_header = data[eth_length:20+eth_length]
iph = struct.unpack('!BBHHHBBH4s4s' , ip_header)
version_ihl = iph[0]
ihl = version_ihl & 0xF
iph_length = ihl * 4
protocol = iph[6]
s_addr = socket.inet_ntoa(iph[8])
d_addr = socket.inet_ntoa(iph[9])
# udp_header = data[iph_length+eth_length:iph_length+20+eth_length]
# udph = struct.unpack('!HHLLBBHHH' , udp_header)
# print "[{}] - {}:{} -> {}:{}".format(protocol, s_addr,udph[0], d_addr,udph[1])
def writable(self):
return len(self.buffer) > 0
def handle_write(self):
""" Write local buffer to interface """
try:
packet = self.buffer.pop()
logging.debug('Writing {}byte packet to device'.format(len(packet)))
self.dev.write(packet)
except IndexError:
pass
except OSError as e:
if e.errno == 22:
# Invalid packet
logging.debug('Failed to write invalid packet "{}"'.format(packet))
else:
logging.exception('Writing "{}" to device caused exception: {}'.format(packet, e.strerror))
except Exception as e:
logging.exception('Writing "{}" to device caused exception: {}'.format(packet, e.strerror))
def write(self, packet):
""" Forward data from loadbalancers to local buffer """
if packet:
# self.validate(packet)
self.buffer.append(packet)
def handle_read_event(self):
""" Forward received packets to loadbalancers """
packet = self.dev.read()
self.balance_data_round_robin(packet)
def balance_data_round_robin(self, packet):
""" Use Round Robin to distribute each packet via revolving loadbalancers """
if len(self.loadbalancer_pool) == 0:
return
# logging.debug('Sending {}byte packet via {}'.format(len(packet), repr(self.loadbalancer_pool[self.rr])))
self.loadbalancer_pool[self.rr].send(packet)
self.rr = self.rr+1 if self.rr < len(self.loadbalancer_pool)-1 else 0
def quit(self):
""" Gracefully close all loadbalancers and self """
self.shutdown = True
logging.debug('Closing loadbalancers...')
# Loadbalancer modifies the pool in close, so make a static list
for s in list(self.loadbalancer_pool):
s.handle_close()
if self.loadbalancer_pool:
logging.debug('Waiting for loadbalancers to close...')
for i in range(5):
if len(self.loadbalancer_pool) == 0:
break
time.sleep(1)
else:
for s in self.loadbalancer_pool:
s.close()
del s
logging.debug('Closing self...')
self.dev.close()
class LoadbalancerClientControl(LoadbalancerControl):
def __init__(self, destination, interfaces, options):
LoadbalancerControl.__init__(self, options)
self.destination = destination
for interface_specs in interfaces:
self.assign_loadbalancer_to_interface(interface_specs)
def assign_loadbalancer_to_interface(self, interface_specs):
""" Build a loadbalancer, which binds to the specified interface address """
logging.debug('Building Loadbalancer for {}'.format(interface_specs))
balancer = LoadbalancerClient(self, interface_specs)
self.loadbalancer_pool.append(balancer)
class LoadbalancerServerControlHelper(asyncore.dispatcher):
""" Helper class to spawn server-loadbalancers for connecting client-loadbalancers """
def __init__(self, control):
asyncore.dispatcher.__init__(self)
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.set_reuse_addr()
self.bind(('0.0.0.0', control.port))
self.listen(10)
self.control = control
logging.debug('Waiting for connections on {}:{}'.format(*self.socket.getsockname()))
def readable(self): return True
def writable(self): return True
def handle_accept(self):
""" Spawn a many loadbalancer as the client brings """
pair = self.accept()
if pair is not None:
sock, addr = pair
logging.info('Incoming connection from {}'.format(repr(addr)))
handler = LoadbalancerServer(sock, self.control)
self.control.loadbalancer_pool.append(handler)
class LoadbalancerServerControl(LoadbalancerControl):
def __init__(self, options):
LoadbalancerControl.__init__(self, options)
self.helper = LoadbalancerServerControlHelper(self)
if __name__ == '__main__':
import argparse
argparser = argparse.ArgumentParser(description="Creates a tun/tap device, which sends packets via multiple interfaces to a corresponding server. This is an implementation of link aggregation / bonding, except with a dynamic distribution algorithm, allowing for example for weighted interfaces.", epilog="Created and Maintained by Kai Sisterhenn under GPLv3, sistason@sistason.de")
argparser.add_argument('--remote', '-r', help='Run as client, connecting to specified destination IP')
argparser.add_argument('interfaces', nargs='*', help='Set the outgoing interfaces[:port], which should be used to balance the traffic (client option).')
argparser.add_argument('--port', '-p', type=int, default=11111, help='Set the port on which to connect to / listen on')
# TODO: to two-factor-authentication
argparser.add_argument('--secret','-s', help='Set a passphrase to authenticate connecting clients. Will stop accidental usage by other programs, but is transmitted trivially in the clear, so don\'t think it does security.')
argparser.add_argument('--name', '-n', help='Name of the tap/tun device', default='')
argparser.add_argument('--tun', '-t', type=bool, help='Use a tun device instead of a tap device', default=False)
argparser.add_argument('--address', '-a', help='Address of the tun/tap device')
p=vars(argparser.parse_args())
destination = p['remote']
interfaces = p['interfaces']
options = {'port':p['port'], 'secret':p['secret'], 'name':p['name'], 'tap':not p['tun'], 'tunnel_address':p['address']}
logging.basicConfig(format='%(levelname)s:%(funcName)s\t\t%(message)s', level=logging.INFO)
if destination:
loadbalancer = LoadbalancerClientControl(destination, interfaces, options)
else:
loadbalancer = LoadbalancerServerControl(options)
try:
asyncore.loop()
except Exception as e:
logging.exception(e)
finally:
loadbalancer.quit()