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