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 from zope.interface import implementer
   9
  10 import twisted
  11 from twisted.internet import reactor
  12 import twisted.internet.endpoints
  13 import twisted.logger
  14 from twisted.logger import LogLevel
  15 import twisted.python.constants
  16 from twisted.python.constants import NamedConstant
  17
  18 import ipaddress
  19 from ipaddress import AddressValueError
  20
  21 from optparse import OptionParser
  22 from configparser import ConfigParser
  23 from configparser import NoOptionError
  24
  25 from functools import partial
  26
  27 import collections
  28 import time
  29 import codecs
  30 import traceback
  31
  32 import re as regexp
  33
  34 import hippotat.slip as slip
  35
  36 class DBG(twisted.python.constants.Names):
  37   INIT = NamedConstant()
  38   ROUTE = NamedConstant()
  39   DROP = NamedConstant()
  40   FLOW = NamedConstant()
  41   HTTP = NamedConstant()
  42   TWISTED = NamedConstant()
  43   QUEUE = NamedConstant()
  44   HTTP_CTRL = NamedConstant()
  45   QUEUE_CTRL = NamedConstant()
  46   HTTP_FULL = NamedConstant()
  47   CTRL_DUMP = NamedConstant()
  48   SLIP_FULL = NamedConstant()
  49   DATA_COMPLETE = NamedConstant()
  50
  51 _hex_codec = codecs.getencoder('hex_codec')
  52
  53 #---------- logging ----------
  54
  55 org_stderr = sys.stderr
  56
  57 log = twisted.logger.Logger()
  58
  59 debug_set = set()
  60 debug_def_detail = DBG.HTTP
  61
  62 def log_debug(dflag, msg, idof=None, d=None):
  63   if dflag not in debug_set: return
  64   #print('---------------->',repr((dflag, msg, idof, d)), file=sys.stderr)
  65   if idof is not None:
  66     msg = '[%#x] %s' % (id(idof), msg)
  67   if d is not None:
  68     trunc = ''
  69     if not DBG.DATA_COMPLETE in debug_set:
  70       if len(d) > 64:
  71         d = d[0:64]
  72         trunc = '...'
  73     d = _hex_codec(d)[0].decode('ascii')
  74     msg += ' ' + d + trunc
  75   log.info('{dflag} {msgcore}', dflag=dflag, msgcore=msg)
  76
  77 @implementer(twisted.logger.ILogFilterPredicate)
  78 class LogNotBoringTwisted:
  79   def __call__(self, event):
  80     yes = twisted.logger.PredicateResult.yes
  81     no  = twisted.logger.PredicateResult.no
  82     try:
  83       if event.get('log_level') != LogLevel.info:
  84         return yes
  85       dflag = event.get('dflag')
  86       if dflag                         in debug_set: return yes
  87       if dflag is None and DBG.TWISTED in debug_set: return yes
  88       return no
  89     except Exception:
  90       print(traceback.format_exc(), file=org_stderr)
  91       return yes
  92
  93 #---------- default config ----------
  94
  95 defcfg = '''
  96 [DEFAULT]
  97 #[<client>] overrides
  98 max_batch_down = 65536           # used by server, subject to [limits]
  99 max_queue_time = 10              # used by server, subject to [limits]
 100 target_requests_outstanding = 3  # must match; subject to [limits] on server
 101 http_timeout = 30                # used by both } must be
 102 http_timeout_grace = 5           # used by both }  compatible
 103 max_requests_outstanding = 4     # used by client
 104 max_batch_up = 4000              # used by client
 105 http_retry = 5                   # used by client
 106
 107 #[server] or [<client>] overrides
 108 ipif = userv root ipif %(local)s,%(peer)s,%(mtu)s,slip %(rnets)s
 109 # extra interpolations:  %(local)s        %(peer)s          %(rnet)s
 110 #  obtained   on server  [virtual]server  [virtual]relay    [virtual]network
 111 #      from   on client  <client>         [virtual]server   [virtual]routes
 112
 113 [virtual]
 114 mtu = 1500
 115 routes = ''
 116 # network = <prefix>/<len>  # mandatory for server
 117 # server  = <ipaddr>   # used by both, default is computed from `network'
 118 # relay   = <ipaddr>   # used by server, default from `network' and `server'
 119 #  default server is first host in network
 120 #  default relay is first host which is not server
 121
 122 [server]
 123 # addrs = 127.0.0.1 ::1    # mandatory for server
 124 port = 80                  # used by server
 125 # url              # used by client; default from first `addrs' and `port'
 126
 127 # [<client-ip4-or-ipv6-address>]
 128 # password = <password>    # used by both, must match
 129
 130 [limits]
 131 max_batch_down = 262144           # used by server
 132 max_queue_time = 121              # used by server
 133 http_timeout = 121                # used by server
 134 target_requests_outstanding = 10  # used by server
 135 '''
 136
 137 # these need to be defined here so that they can be imported by import *
 138 cfg = ConfigParser()
 139 optparser = OptionParser()
 140
 141 _mimetrans = bytes.maketrans(b'-'+slip.esc, slip.esc+b'-')
 142 def mime_translate(s):
 143   # SLIP-encoded packets cannot contain ESC ESC.
 144   # Swap `-' and ESC.  The result cannot contain `--'
 145   return s.translate(_mimetrans)
 146
 147 class ConfigResults:
 148   def __init__(self, d = { }):
 149     self.__dict__ = d
 150   def __repr__(self):
 151     return 'ConfigResults('+repr(self.__dict__)+')'
 152
 153 c = ConfigResults()
 154
 155 def log_discard(packet, iface, saddr, daddr, why):
 156   log_debug(DBG.DROP,
 157             'discarded packet [%s] %s -> %s: %s' % (iface, saddr, daddr, why),
 158             d=packet)
 159
 160 #---------- packet parsing ----------
 161
 162 def packet_addrs(packet):
 163   version = packet[0] >> 4
 164   if version == 4:
 165     addrlen = 4
 166     saddroff = 3*4
 167     factory = ipaddress.IPv4Address
 168   elif version == 6:
 169     addrlen = 16
 170     saddroff = 2*4
 171     factory = ipaddress.IPv6Address
 172   else:
 173     raise ValueError('unsupported IP version %d' % version)
 174   saddr = factory(packet[ saddroff           : saddroff + addrlen   ])
 175   daddr = factory(packet[ saddroff + addrlen : saddroff + addrlen*2 ])
 176   return (saddr, daddr)
 177
 178 #---------- address handling ----------
 179
 180 def ipaddr(input):
 181   try:
 182     r = ipaddress.IPv4Address(input)
 183   except AddressValueError:
 184     r = ipaddress.IPv6Address(input)
 185   return r
 186
 187 def ipnetwork(input):
 188   try:
 189     r = ipaddress.IPv4Network(input)
 190   except NetworkValueError:
 191     r = ipaddress.IPv6Network(input)
 192   return r
 193
 194 #---------- ipif (SLIP) subprocess ----------
 195
 196 class SlipStreamDecoder():
 197   def __init__(self, desc, on_packet):
 198     self._buffer = b''
 199     self._on_packet = on_packet
 200     self._desc = desc
 201     self._log('__init__')
 202
 203   def _log(self, msg, **kwargs):
 204     log_debug(DBG.SLIP_FULL, 'slip %s: %s' % (self._desc, msg), **kwargs)
 205
 206   def inputdata(self, data):
 207     self._log('inputdata', d=data)
 208     packets = slip.decode(data)
 209     packets[0] = self._buffer + packets[0]
 210     self._buffer = packets.pop()
 211     for packet in packets:
 212       self._maybe_packet(packet)
 213     self._log('bufremain', d=self._buffer)
 214
 215   def _maybe_packet(self, packet):
 216     self._log('maybepacket', d=packet)
 217     if len(packet):
 218       self._on_packet(packet)
 219
 220   def flush(self):
 221     self._log('flush')
 222     self._maybe_packet(self._buffer)
 223     self._buffer = b''
 224
 225 class _IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol):
 226   def __init__(self, router):
 227     self._router = router
 228     self._decoder = SlipStreamDecoder('ipif', self.slip_on_packet)
 229   def connectionMade(self): pass
 230   def outReceived(self, data):
 231     self._decoder.inputdata(data)
 232   def slip_on_packet(self, packet):
 233     (saddr, daddr) = packet_addrs(packet)
 234     if saddr.is_link_local or daddr.is_link_local:
 235       log_discard(packet, 'ipif', saddr, daddr, 'link-local')
 236       return
 237     self._router(packet, saddr, daddr)
 238   def processEnded(self, status):
 239     status.raiseException()
 240
 241 def start_ipif(command, router):
 242   global ipif
 243   ipif = _IpifProcessProtocol(router)
 244   reactor.spawnProcess(ipif,
 245                        '/bin/sh',['sh','-xc', command],
 246                        childFDs={0:'w', 1:'r', 2:2},
 247                        env=None)
 248
 249 def queue_inbound(packet):
 250   log_debug(DBG.FLOW, "queue_inbound", d=packet)
 251   ipif.transport.write(slip.delimiter)
 252   ipif.transport.write(slip.encode(packet))
 253   ipif.transport.write(slip.delimiter)
 254
 255 #---------- packet queue ----------
 256
 257 class PacketQueue():
 258   def __init__(self, desc, max_queue_time):
 259     self._desc = desc
 260     assert(desc + '')
 261     self._max_queue_time = max_queue_time
 262     self._pq = collections.deque() # packets
 263
 264   def _log(self, dflag, msg, **kwargs):
 265     log_debug(dflag, self._desc+' pq: '+msg, **kwargs)
 266
 267   def append(self, packet):
 268     self._log(DBG.QUEUE, 'append', d=packet)
 269     self._pq.append((time.monotonic(), packet))
 270
 271   def nonempty(self):
 272     self._log(DBG.QUEUE, 'nonempty ?')
 273     while True:
 274       try: (queuetime, packet) = self._pq[0]
 275       except IndexError:
 276         self._log(DBG.QUEUE, 'nonempty ? empty.')
 277         return False
 278
 279       age = time.monotonic() - queuetime
 280       if age > self._max_queue_time:
 281         # strip old packets off the front
 282         self._log(DBG.QUEUE, 'dropping (old)', d=packet)
 283         self._pq.popleft()
 284         continue
 285
 286       self._log(DBG.QUEUE, 'nonempty ? nonempty.')
 287       return True
 288
 289   def process(self, sizequery, moredata, max_batch):
 290     # sizequery() should return size of batch so far
 291     # moredata(s) should add s to batch
 292     self._log(DBG.QUEUE, 'process...')
 293     while True:
 294       try: (dummy, packet) = self._pq[0]
 295       except IndexError:
 296         self._log(DBG.QUEUE, 'process... empty')
 297         break
 298
 299       self._log(DBG.QUEUE_CTRL, 'process... packet', d=packet)
 300
 301       encoded = slip.encode(packet)
 302       sofar = sizequery()
 303
 304       self._log(DBG.QUEUE_CTRL,
 305                 'process... (sofar=%d, max=%d) encoded' % (sofar, max_batch),
 306                 d=encoded)
 307
 308       if sofar > 0:
 309         if sofar + len(slip.delimiter) + len(encoded) > max_batch:
 310           self._log(DBG.QUEUE_CTRL, 'process... overflow')
 311           break
 312         moredata(slip.delimiter)
 313
 314       moredata(encoded)
 315       self._pq.popleft()
 316
 317 #---------- error handling ----------
 318
 319 _crashing = False
 320
 321 def crash(err):
 322   global _crashing
 323   _crashing = True
 324   print('========== CRASH ==========', err,
 325         '===========================', file=sys.stderr)
 326   try: reactor.stop()
 327   except twisted.internet.error.ReactorNotRunning: pass
 328
 329 def crash_on_defer(defer):
 330   defer.addErrback(lambda err: crash(err))
 331
 332 def crash_on_critical(event):
 333   if event.get('log_level') >= LogLevel.critical:
 334     crash(twisted.logger.formatEvent(event))
 335
 336 #---------- config processing ----------
 337
 338 def process_cfg_common_always():
 339   global mtu
 340   c.mtu = cfg.get('virtual','mtu')
 341
 342 def process_cfg_ipif(section, varmap):
 343   for d, s in varmap:
 344     try: v = getattr(c, s)
 345     except AttributeError: continue
 346     setattr(c, d, v)
 347
 348   #print(repr(c))
 349
 350   c.ipif_command = cfg.get(section,'ipif', vars=c.__dict__)
 351
 352 def process_cfg_network():
 353   c.network = ipnetwork(cfg.get('virtual','network'))
 354   if c.network.num_addresses < 3 + 2:
 355     raise ValueError('network needs at least 2^3 addresses')
 356
 357 def process_cfg_server():
 358   try:
 359     c.server = cfg.get('virtual','server')
 360   except NoOptionError:
 361     process_cfg_network()
 362     c.server = next(c.network.hosts())
 363
 364 class ServerAddr():
 365   def __init__(self, port, addrspec):
 366     self.port = port
 367     # also self.addr
 368     try:
 369       self.addr = ipaddress.IPv4Address(addrspec)
 370       self._endpointfactory = twisted.internet.endpoints.TCP4ServerEndpoint
 371       self._inurl = b'%s'
 372     except AddressValueError:
 373       self.addr = ipaddress.IPv6Address(addrspec)
 374       self._endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint
 375       self._inurl = b'[%s]'
 376   def make_endpoint(self):
 377     return self._endpointfactory(reactor, self.port, self.addr)
 378   def url(self):
 379     url = b'http://' + (self._inurl % str(self.addr).encode('ascii'))
 380     if self.port != 80: url += b':%d' % self.port
 381     url += b'/'
 382     return url
 383
 384 def process_cfg_saddrs():
 385   try: port = cfg.getint('server','port')
 386   except NoOptionError: port = 80
 387
 388   c.saddrs = [ ]
 389   for addrspec in cfg.get('server','addrs').split():
 390     sa = ServerAddr(port, addrspec)
 391     c.saddrs.append(sa)
 392
 393 def process_cfg_clients(constructor):
 394   c.clients = [ ]
 395   for cs in cfg.sections():
 396     if not (':' in cs or '.' in cs): continue
 397     ci = ipaddr(cs)
 398     pw = cfg.get(cs, 'password')
 399     pw = pw.encode('utf-8')
 400     constructor(ci,cs,pw)
 401
 402 #---------- startup ----------
 403
 404 def common_startup():
 405   optparser.add_option('-c', '--config', dest='configfile',
 406                        default='/etc/hippotat/config')
 407
 408   def dfs_less_detailed(dl):
 409     return [df for df in DBG.iterconstants() if df <= dl]
 410
 411   def ds_default(od,os,dl,op):
 412     global debug_set
 413     debug_set = set(dfs_less_detailed(debug_def_detail))
 414
 415   def ds_select(od,os, spec, op):
 416     for it in spec.split(','):
 417
 418       if it.startswith('-'):
 419         mutator = debug_set.discard
 420         it = it[1:]
 421       else:
 422         mutator = debug_set.add
 423
 424       if it == '+':
 425         dfs = DBG.iterconstants()
 426
 427       else:
 428         if it.endswith('+'):
 429           mapper = dfs_less_detailed
 430           it = it[0:len(it)-1]
 431         else:
 432           mapper = lambda x: [x]
 433
 434           try:
 435             dfspec = DBG.lookupByName(it)
 436           except ValueError:
 437             optparser.error('unknown debug flag %s in --debug-select' % it)
 438
 439         dfs = mapper(dfspec)
 440
 441       for df in dfs:
 442         mutator(df)
 443
 444   optparser.add_option('-D', '--debug',
 445                        nargs=0,
 446                        action='callback',
 447                        help='enable default debug (to stdout)',
 448                        callback= ds_default)
 449
 450   optparser.add_option('--debug-select',
 451                        nargs=1,
 452                        type='string',
 453                        metavar='[-]DFLAG[+]|[-]+,...',
 454                        help=
 455 '''enable (`-': disable) each specified DFLAG;
 456 `+': do same for all "more interesting" DFLAGSs;
 457 just `+': all DFLAGs.
 458   DFLAGS: ''' + ' '.join([df.name for df in DBG.iterconstants()]),
 459                        action='callback',
 460                        callback= ds_select)
 461
 462   (opts, args) = optparser.parse_args()
 463   if len(args): optparser.error('no non-option arguments please')
 464
 465   #print(repr(debug_set), file=sys.stderr)
 466
 467   re = regexp.compile('#.*')
 468   cfg.read_string(re.sub('', defcfg))
 469   cfg.read(opts.configfile)
 470
 471   log_formatter = twisted.logger.formatEventAsClassicLogText
 472   stdout_obs = twisted.logger.FileLogObserver(sys.stdout, log_formatter)
 473   stderr_obs = twisted.logger.FileLogObserver(sys.stderr, log_formatter)
 474   pred = twisted.logger.LogLevelFilterPredicate(LogLevel.error)
 475   stdsomething_obs = twisted.logger.FilteringLogObserver(
 476     stderr_obs, [pred], stdout_obs
 477   )
 478   log_observer = twisted.logger.FilteringLogObserver(
 479     stdsomething_obs, [LogNotBoringTwisted()]
 480   )
 481   #log_observer = stdsomething_obs
 482   twisted.logger.globalLogBeginner.beginLoggingTo(
 483     [ log_observer, crash_on_critical ]
 484     )
 485
 486 def common_run():
 487   log_debug(DBG.INIT, 'entering reactor')
 488   if not _crashing: reactor.run()
 489   print('CRASHED (end)', file=sys.stderr)