X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=hippotat%2F__init__.py;h=6f0d3e87d8a2ba2dcf5f7d4e1f7ea154b716f22e;hb=88487243bc0be906c63258005df75b96bc8165a5;hp=ee844cd53faa83b09602c3231043b2d9fb588861;hpb=c491fea13a428b0c33df3294b23db7e2773e8dc6;p=hippotat.git

diff --git a/hippotat/__init__.py b/hippotat/__init__.py
index ee844cd..6f0d3e8 100644
--- a/hippotat/__init__.py
+++ b/hippotat/__init__.py
@@ -1,10 +1,35 @@
 # -*- python -*-
 
-import hippotat.slip as slip
+import signal
+signal.signal(signal.SIGINT, signal.SIG_DFL)
+
+import twisted
+from twisted.internet import reactor
+from twisted.logger import LogLevel
 
 import ipaddress
 from ipaddress import AddressValueError
 
+import hippotat.slip as slip
+
+from optparse import OptionParser
+from configparser import ConfigParser
+from configparser import NoOptionError
+
+import collections
+
+# these need to be defined here so that they can be imported by import *
+cfg = ConfigParser()
+optparser = OptionParser()
+
+class ConfigResults:
+  def __init__(self, d = { }):
+    self.__dict__ = d
+  def __repr__(self):
+    return 'ConfigResults('+repr(self.__dict__)+')'
+
+c = ConfigResults()
+
 #---------- packet parsing ----------
 
 def packet_addrs(packet):
@@ -38,3 +63,158 @@ def ipnetwork(input):
   except NetworkValueError:
     r = ipaddress.IPv6Network(input)
   return r
+
+#---------- ipif (SLIP) subprocess ----------
+
+class _IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol):
+  def __init__(self, router):
+    self._buffer = b''
+    self._router = router
+  def connectionMade(self): pass
+  def outReceived(self, data):
+    #print('RECV ', repr(data))
+    self._buffer += data
+    packets = slip.decode(self._buffer)
+    self._buffer = packets.pop()
+    for packet in packets:
+      if not len(packet): continue
+      (saddr, daddr) = packet_addrs(packet)
+      self._router(packet, saddr, daddr)
+  def processEnded(self, status):
+    status.raiseException()
+
+def start_ipif(command, router):
+  global ipif
+  ipif = _IpifProcessProtocol(router)
+  reactor.spawnProcess(ipif,
+                       '/bin/sh',['sh','-xc', command],
+                       childFDs={0:'w', 1:'r', 2:2})
+
+def queue_inbound(packet):
+  ipif.transport.write(slip.delimiter)
+  ipif.transport.write(slip.encode(packet))
+  ipif.transport.write(slip.delimiter)
+
+#---------- packet queue ----------
+
+class PacketQueue():
+  def __init__(self, max_queue_time):
+    self._max_queue_time = max_queue_time
+    self._pq = collections.deque() # packets
+
+  def append(self, packet):
+    self._pq.append((time.monotonic(), packet))
+
+  def nonempty(self):
+    while True:
+      try: (queuetime, packet) = self._pq[0]
+      except IndexError: return False
+
+      age = time.monotonic() - queuetime
+      if age > self.max_queue_time:
+        # strip old packets off the front
+        self._pq.popleft()
+        continue
+
+      return True
+
+  def popleft(self):
+    # caller must have checked nonempty
+    try: (dummy, packet) = self._pq[0]
+    except IndexError: return None
+    return packet
+
+#---------- error handling ----------
+
+def crash(err):
+  print('CRASH ', err, file=sys.stderr)
+  try: reactor.stop()
+  except twisted.internet.error.ReactorNotRunning: pass
+
+def crash_on_defer(defer):
+  defer.addErrback(lambda err: crash(err))
+
+def crash_on_critical(event):
+  if event.get('log_level') >= LogLevel.critical:
+    crash(twisted.logger.formatEvent(event))
+
+#---------- config processing ----------
+
+def process_cfg_common_always():
+  global mtu
+  c.mtu = cfg.get('virtual','mtu')
+
+def process_cfg_ipif(section, varmap):
+  for d, s in varmap:
+    try: v = getattr(c, s)
+    except KeyError: pass
+    setattr(c, d, v)
+
+  print(repr(c))
+
+  c.ipif_command = cfg.get(section,'ipif', vars=c.__dict__)
+
+def process_cfg_network():
+  c.network = ipnetwork(cfg.get('virtual','network'))
+  if c.network.num_addresses < 3 + 2:
+    raise ValueError('network needs at least 2^3 addresses')
+
+def process_cfg_server():
+  try:
+    c.server = cfg.get('virtual','server')
+  except NoOptionError:
+    process_cfg_network()
+    c.server = next(c.network.hosts())
+
+class ServerAddr():
+  def __init__(self, port, addrspec):
+    self.port = port
+    # also self.addr
+    try:
+      self.addr = ipaddress.IPv4Address(addrspec)
+      self._endpointfactory = twisted.internet.endpoints.TCP4ServerEndpoint
+      self._inurl = '%s'
+    except AddressValueError:
+      self.addr = ipaddress.IPv6Address(addrspec)
+      self._endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint
+      self._inurl = '[%s]'
+  def make_endpoint(self):
+    return self._endpointfactory(reactor, self.port, self.addr)
+  def url(self):
+    url = 'http://' + (self._inurl % self.addr)
+    if self.port != 80: url += ':%d' % self.port
+    url += '/'
+    return url
+    
+def process_cfg_saddrs():
+  port = cfg.getint('server','port')
+
+  c.saddrs = [ ]
+  for addrspec in cfg.get('server','addrs').split():
+    sa = ServerAddr(port, addrspec)
+    c.saddrs.append(sa)
+
+def process_cfg_clients(constructor):
+  c.clients = [ ]
+  for cs in cfg.sections():
+    if not (':' in cs or '.' in cs): continue
+    ci = ipaddr(cs)
+    pw = cfg.get(cs, 'password')
+    constructor(ci,cs,pw)
+
+#---------- startup ----------
+
+def common_startup(defcfg):
+  twisted.logger.globalLogPublisher.addObserver(crash_on_critical)
+
+  optparser.add_option('-c', '--config', dest='configfile',
+                       default='/etc/hippotat/config')
+  (opts, args) = optparser.parse_args()
+  if len(args): optparser.error('no non-option arguments please')
+
+  cfg.read_string(defcfg)
+  cfg.read(opts.configfile)
+
+def common_run():
+  reactor.run()
+  print('CRASHED (end)', file=sys.stderr)