mdw@git.distorted.org.uk Git - hippotat/blob - hippotat/__init__.py

   1 # -*- python -*-
   2
   3 import signal
   4 signal.signal(signal.SIGINT, signal.SIG_DFL)
   5
   6 import sys
   7
   8 import twisted
   9 from twisted.internet import reactor
  10 import twisted.internet.endpoints
  11 import twisted.logger
  12 from twisted.logger import LogLevel
  13 import twisted.python.constants
  14 from twisted.python.constants import NamedConstant
  15
  16 import ipaddress
  17 from ipaddress import AddressValueError
  18
  19 from optparse import OptionParser
  20 from configparser import ConfigParser
  21 from configparser import NoOptionError
  22
  23 from functools import partial
  24
  25 import collections
  26 import time
  27 import codecs
  28 import traceback
  29
  30 import re as regexp
  31
  32 import hippotat.slip as slip
  33
  34 class DBG(twisted.python.constants.Names):
  35   ROUTE = NamedConstant()
  36   DROP = NamedConstant()
  37   FLOW = NamedConstant()
  38   HTTP = NamedConstant()
  39   HTTP_CTRL = NamedConstant()
  40   INIT = NamedConstant()
  41   QUEUE = NamedConstant()
  42   QUEUE_CTRL = NamedConstant()
  43   HTTP_FULL = NamedConstant()
  44   SLIP_FULL = NamedConstant()
  45   CTRL_DUMP = NamedConstant()
  46
  47 _hex_codec = codecs.getencoder('hex_codec')
  48
  49 log = twisted.logger.Logger()
  50
  51 def log_debug(dflag, msg, idof=None, d=None):
  52   #print('---------------->',repr((dflag, msg, idof, d)), file=sys.stderr)
  53   if idof is not None:
  54     msg = '[%#x] %s' % (id(idof), msg)
  55   if d is not None:
  56     #d = d[0:64]
  57     d = _hex_codec(d)[0].decode('ascii')
  58     msg += ' ' + d
  59   log.info('{dflag} {msgcore}', dflag=dflag, msgcore=msg)
  60
  61 defcfg = '''
  62 [DEFAULT]
  63 #[<client>] overrides
  64 max_batch_down = 65536           # used by server, subject to [limits]
  65 max_queue_time = 10              # used by server, subject to [limits]
  66 target_requests_outstanding = 3  # must match; subject to [limits] on server
  67 http_timeout = 30                # used by both } must be
  68 http_timeout_grace = 5           # used by both }  compatible
  69 max_requests_outstanding = 4     # used by client
  70 max_batch_up = 4000              # used by client
  71 http_retry = 5                   # used by client
  72
  73 #[server] or [<client>] overrides
  74 ipif = userv root ipif %(local)s,%(peer)s,%(mtu)s,slip %(rnets)s
  75 # extra interpolations:  %(local)s        %(peer)s          %(rnet)s
  76 #  obtained   on server  [virtual]server  [virtual]relay    [virtual]network
  77 #      from   on client  <client>         [virtual]server   [virtual]routes
  78
  79 [virtual]
  80 mtu = 1500
  81 routes = ''
  82 # network = <prefix>/<len>  # mandatory for server
  83 # server  = <ipaddr>   # used by both, default is computed from `network'
  84 # relay   = <ipaddr>   # used by server, default from `network' and `server'
  85 #  default server is first host in network
  86 #  default relay is first host which is not server
  87
  88 [server]
  89 # addrs = 127.0.0.1 ::1    # mandatory for server
  90 port = 80                  # used by server
  91 # url              # used by client; default from first `addrs' and `port'
  92
  93 # [<client-ip4-or-ipv6-address>]
  94 # password = <password>    # used by both, must match
  95
  96 [limits]
  97 max_batch_down = 262144           # used by server
  98 max_queue_time = 121              # used by server
  99 http_timeout = 121                # used by server
 100 target_requests_outstanding = 10  # used by server
 101 '''
 102
 103 # these need to be defined here so that they can be imported by import *
 104 cfg = ConfigParser()
 105 optparser = OptionParser()
 106
 107 _mimetrans = bytes.maketrans(b'-'+slip.esc, slip.esc+b'-')
 108 def mime_translate(s):
 109   # SLIP-encoded packets cannot contain ESC ESC.
 110   # Swap `-' and ESC.  The result cannot contain `--'
 111   return s.translate(_mimetrans)
 112
 113 class ConfigResults:
 114   def __init__(self, d = { }):
 115     self.__dict__ = d
 116   def __repr__(self):
 117     return 'ConfigResults('+repr(self.__dict__)+')'
 118
 119 c = ConfigResults()
 120
 121 def log_discard(packet, iface, saddr, daddr, why):
 122   log_debug(DBG.DROP,
 123             'discarded packet [%s] %s -> %s: %s' % (iface, saddr, daddr, why),
 124             d=packet)
 125
 126 #---------- packet parsing ----------
 127
 128 def packet_addrs(packet):
 129   version = packet[0] >> 4
 130   if version == 4:
 131     addrlen = 4
 132     saddroff = 3*4
 133     factory = ipaddress.IPv4Address
 134   elif version == 6:
 135     addrlen = 16
 136     saddroff = 2*4
 137     factory = ipaddress.IPv6Address
 138   else:
 139     raise ValueError('unsupported IP version %d' % version)
 140   saddr = factory(packet[ saddroff           : saddroff + addrlen   ])
 141   daddr = factory(packet[ saddroff + addrlen : saddroff + addrlen*2 ])
 142   return (saddr, daddr)
 143
 144 #---------- address handling ----------
 145
 146 def ipaddr(input):
 147   try:
 148     r = ipaddress.IPv4Address(input)
 149   except AddressValueError:
 150     r = ipaddress.IPv6Address(input)
 151   return r
 152
 153 def ipnetwork(input):
 154   try:
 155     r = ipaddress.IPv4Network(input)
 156   except NetworkValueError:
 157     r = ipaddress.IPv6Network(input)
 158   return r
 159
 160 #---------- ipif (SLIP) subprocess ----------
 161
 162 class SlipStreamDecoder():
 163   def __init__(self, desc, on_packet):
 164     self._buffer = b''
 165     self._on_packet = on_packet
 166     self._desc = desc
 167     self._log('__init__')
 168
 169   def _log(self, msg, **kwargs):
 170     log_debug(DBG.SLIP_FULL, 'slip %s: %s' % (self._desc, msg), **kwargs)
 171
 172   def inputdata(self, data):
 173     self._log('inputdata', d=data)
 174     packets = slip.decode(data)
 175     packets[0] = self._buffer + packets[0]
 176     self._buffer = packets.pop()
 177     for packet in packets:
 178       self._maybe_packet(packet)
 179     self._log('bufremain', d=self._buffer)
 180
 181   def _maybe_packet(self, packet):
 182     self._log('maybepacket', d=packet)
 183     if len(packet):
 184       self._on_packet(packet)
 185
 186   def flush(self):
 187     self._log('flush')
 188     self._maybe_packet(self._buffer)
 189     self._buffer = b''
 190
 191 class _IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol):
 192   def __init__(self, router):
 193     self._router = router
 194     self._decoder = SlipStreamDecoder('ipif', self.slip_on_packet)
 195   def connectionMade(self): pass
 196   def outReceived(self, data):
 197     self._decoder.inputdata(data)
 198   def slip_on_packet(self, packet):
 199     (saddr, daddr) = packet_addrs(packet)
 200     if saddr.is_link_local or daddr.is_link_local:
 201       log_discard(packet, 'ipif', saddr, daddr, 'link-local')
 202       return
 203     self._router(packet, saddr, daddr)
 204   def processEnded(self, status):
 205     status.raiseException()
 206
 207 def start_ipif(command, router):
 208   global ipif
 209   ipif = _IpifProcessProtocol(router)
 210   reactor.spawnProcess(ipif,
 211                        '/bin/sh',['sh','-xc', command],
 212                        childFDs={0:'w', 1:'r', 2:2},
 213                        env=None)
 214
 215 def queue_inbound(packet):
 216   log_debug(DBG.FLOW, "queue_inbound", d=packet)
 217   ipif.transport.write(slip.delimiter)
 218   ipif.transport.write(slip.encode(packet))
 219   ipif.transport.write(slip.delimiter)
 220
 221 #---------- packet queue ----------
 222
 223 class PacketQueue():
 224   def __init__(self, desc, max_queue_time):
 225     self._desc = desc
 226     assert(desc + '')
 227     self._max_queue_time = max_queue_time
 228     self._pq = collections.deque() # packets
 229
 230   def _log(self, dflag, msg, **kwargs):
 231     log_debug(dflag, self._desc+' pq: '+msg, **kwargs)
 232
 233   def append(self, packet):
 234     self._log(DBG.QUEUE, 'append', d=packet)
 235     self._pq.append((time.monotonic(), packet))
 236
 237   def nonempty(self):
 238     self._log(DBG.QUEUE, 'nonempty ?')
 239     while True:
 240       try: (queuetime, packet) = self._pq[0]
 241       except IndexError:
 242         self._log(DBG.QUEUE, 'nonempty ? empty.')
 243         return False
 244
 245       age = time.monotonic() - queuetime
 246       if age > self._max_queue_time:
 247         # strip old packets off the front
 248         self._log(DBG.QUEUE, 'dropping (old)', d=packet)
 249         self._pq.popleft()
 250         continue
 251
 252       self._log(DBG.QUEUE, 'nonempty ? nonempty.')
 253       return True
 254
 255   def process(self, sizequery, moredata, max_batch):
 256     # sizequery() should return size of batch so far
 257     # moredata(s) should add s to batch
 258     self._log(DBG.QUEUE, 'process...')
 259     while True:
 260       try: (dummy, packet) = self._pq[0]
 261       except IndexError:
 262         self._log(DBG.QUEUE, 'process... empty')
 263         break
 264
 265       self._log(DBG.QUEUE_CTRL, 'process... packet', d=packet)
 266
 267       encoded = slip.encode(packet)
 268       sofar = sizequery()
 269
 270       self._log(DBG.QUEUE_CTRL,
 271                 'process... (sofar=%d, max=%d) encoded' % (sofar, max_batch),
 272                 d=encoded)
 273
 274       if sofar > 0:
 275         if sofar + len(slip.delimiter) + len(encoded) > max_batch:
 276           self._log(DBG.QUEUE_CTRL, 'process... overflow')
 277           break
 278         moredata(slip.delimiter)
 279
 280       moredata(encoded)
 281       self._pq.popleft()
 282
 283 #---------- error handling ----------
 284
 285 _crashing = False
 286
 287 def crash(err):
 288   global _crashing
 289   _crashing = True
 290   print('========== CRASH ==========', err,
 291         '===========================', file=sys.stderr)
 292   try: reactor.stop()
 293   except twisted.internet.error.ReactorNotRunning: pass
 294
 295 def crash_on_defer(defer):
 296   defer.addErrback(lambda err: crash(err))
 297
 298 def crash_on_critical(event):
 299   if event.get('log_level') >= LogLevel.critical:
 300     crash(twisted.logger.formatEvent(event))
 301
 302 #---------- config processing ----------
 303
 304 def process_cfg_common_always():
 305   global mtu
 306   c.mtu = cfg.get('virtual','mtu')
 307
 308 def process_cfg_ipif(section, varmap):
 309   for d, s in varmap:
 310     try: v = getattr(c, s)
 311     except AttributeError: continue
 312     setattr(c, d, v)
 313
 314   #print(repr(c))
 315
 316   c.ipif_command = cfg.get(section,'ipif', vars=c.__dict__)
 317
 318 def process_cfg_network():
 319   c.network = ipnetwork(cfg.get('virtual','network'))
 320   if c.network.num_addresses < 3 + 2:
 321     raise ValueError('network needs at least 2^3 addresses')
 322
 323 def process_cfg_server():
 324   try:
 325     c.server = cfg.get('virtual','server')
 326   except NoOptionError:
 327     process_cfg_network()
 328     c.server = next(c.network.hosts())
 329
 330 class ServerAddr():
 331   def __init__(self, port, addrspec):
 332     self.port = port
 333     # also self.addr
 334     try:
 335       self.addr = ipaddress.IPv4Address(addrspec)
 336       self._endpointfactory = twisted.internet.endpoints.TCP4ServerEndpoint
 337       self._inurl = b'%s'
 338     except AddressValueError:
 339       self.addr = ipaddress.IPv6Address(addrspec)
 340       self._endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint
 341       self._inurl = b'[%s]'
 342   def make_endpoint(self):
 343     return self._endpointfactory(reactor, self.port, self.addr)
 344   def url(self):
 345     url = b'http://' + (self._inurl % str(self.addr).encode('ascii'))
 346     if self.port != 80: url += b':%d' % self.port
 347     url += b'/'
 348     return url
 349
 350 def process_cfg_saddrs():
 351   try: port = cfg.getint('server','port')
 352   except NoOptionError: port = 80
 353
 354   c.saddrs = [ ]
 355   for addrspec in cfg.get('server','addrs').split():
 356     sa = ServerAddr(port, addrspec)
 357     c.saddrs.append(sa)
 358
 359 def process_cfg_clients(constructor):
 360   c.clients = [ ]
 361   for cs in cfg.sections():
 362     if not (':' in cs or '.' in cs): continue
 363     ci = ipaddr(cs)
 364     pw = cfg.get(cs, 'password')
 365     pw = pw.encode('utf-8')
 366     constructor(ci,cs,pw)
 367
 368 #---------- startup ----------
 369
 370 def common_startup():
 371   log_formatter = twisted.logger.formatEventAsClassicLogText
 372   stdout_obs = twisted.logger.FileLogObserver(sys.stdout, log_formatter)
 373   stderr_obs = twisted.logger.FileLogObserver(sys.stderr, log_formatter)
 374   pred = twisted.logger.LogLevelFilterPredicate(LogLevel.error)
 375   log_observer = twisted.logger.FilteringLogObserver(
 376     stderr_obs, [pred], stdout_obs
 377   )
 378   twisted.logger.globalLogBeginner.beginLoggingTo(
 379     [ log_observer, crash_on_critical ]
 380     )
 381
 382   optparser.add_option('-c', '--config', dest='configfile',
 383                        default='/etc/hippotat/config')
 384   (opts, args) = optparser.parse_args()
 385   if len(args): optparser.error('no non-option arguments please')
 386
 387   re = regexp.compile('#.*')
 388   cfg.read_string(re.sub('', defcfg))
 389   cfg.read(opts.configfile)
 390
 391 def common_run():
 392   log_debug(DBG.INIT, 'entering reactor')
 393   if not _crashing: reactor.run()
 394   print('CRASHED (end)', file=sys.stderr)