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