I've made a Tun class that wraps pytun.TunTapDevice :
from pytun import TunTapDevice
class Tun(object):
def __init__(self,name='tun',addr=None,dstaddr=None,netmask=None,mtu=None):
tun = TunTapDevice(name=name)
if addr : tun.addr = addr
if dstaddr : tun.dstaddr = dstaddr
if netmask : tun.netmask = netmask
if mtu : tun.mtu = mtu
self._tun = tun
self.up = self._tun.up
self.down = self._tun.down
self.read = self._tun.read
self.write = self._tun.write
self.close = self._tun.close
@property
def name(self):
return self._tun.name
@property
def mtu(self):
return self._tun.mtu
The question is not about how to write a tunnel, but about how to write a test-case to ensure it works properly in unix-like oses using python unit-testing.
What should I write out to it to ensure is works? Maybe an ARP request, ICMP, DNS packet or anything else:
class TestTunnel(unittest.TestCase):
def setUp(self):
self.tun = Tun(name='tun0', addr='192.168.0.23', netmask='255.255.255.0',mtu=1500)
def test_tunnel(self):
self.tun.write(?????)
self.assertEqual(self.tun.read(),????)
EDIT 1:
finally i got it by this code:
from select import select
import dpkt
import struct
class TunnelTestCase( unittest.TestCase):
def setUp(self):
self.tun = Tun(name='testtun',
addr='192.168.6.92',
dstaddr='192.168.6.93',
netmask='255.255.255.0',
mtu=1500)
self.tun.up()
def _ip2str(self,ip):
return '.'.join([str(i) for i in struct.unpack('!BBBB',ip)])
def test_echo(self):
reqPack = dpkt.ip.IP('E\x00\x00T\x00\x00@\x00@\x01\xac\x9f\xc0\xa8\x06]\xc0\xa8\x06\\\x08\x00\x1c\xae\t\xc7\x00\x01\x0f\x8adQq\xab\x01\x00\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234567')
self.tun.write(reqPack.pack())
r,_w,_ex = select([self.tun],[],[],4)
if len(r) and r[0] == self.tun:
replyPack = dpkt.ip.IP(self.tun.read())
self.assertEqual(self._ip2str(replyPack.src), self.tun.addr)
self.assertEqual(self._ip2str(replyPack.dst), self.tun.dstaddr)
return
self.assert_(False, 'ICMP Echo timeout, the tunnel interface may not works properly in your system.')