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

   1 # -*- python -*-
   2
   3 import signal
   4 signal.signal(signal.SIGINT, signal.SIG_DFL)
   5
   6 import sys
   7 import os
   8
   9 from zope.interface import implementer
  10
  11 import twisted
  12 from twisted.internet import reactor
  13 import twisted.internet.endpoints
  14 import twisted.logger
  15 from twisted.logger import LogLevel
  16 import twisted.python.constants
  17 from twisted.python.constants import NamedConstant
  18
  19 import ipaddress
  20 from ipaddress import AddressValueError
  21
  22 from optparse import OptionParser
  23 import configparser
  24 from configparser import ConfigParser
  25 from configparser import NoOptionError
  26
  27 from functools import partial
  28
  29 import collections
  30 import time
  31 import codecs
  32 import traceback
  33
  34 import re as regexp
  35
  36 import hippotatlib.slip as slip
  37
  38 class DBG(twisted.python.constants.Names):
  39   INIT = NamedConstant()
  40   CONFIG = NamedConstant()
  41   ROUTE = NamedConstant()
  42   DROP = NamedConstant()
  43   FLOW = NamedConstant()
  44   HTTP = NamedConstant()
  45   TWISTED = NamedConstant()
  46   QUEUE = NamedConstant()
  47   HTTP_CTRL = NamedConstant()
  48   QUEUE_CTRL = NamedConstant()
  49   HTTP_FULL = NamedConstant()
  50   CTRL_DUMP = NamedConstant()
  51   SLIP_FULL = NamedConstant()
  52   DATA_COMPLETE = NamedConstant()
  53
  54 _hex_codec = codecs.getencoder('hex_codec')
  55
  56 #---------- logging ----------
  57
  58 org_stderr = sys.stderr
  59
  60 log = twisted.logger.Logger()
  61
  62 debug_set = set()
  63 debug_def_detail = DBG.HTTP
  64
  65 def log_debug(dflag, msg, idof=None, d=None):
  66   if dflag not in debug_set: return
  67   #print('---------------->',repr((dflag, msg, idof, d)), file=sys.stderr)
  68   if idof is not None:
  69     msg = '[%#x] %s' % (id(idof), msg)
  70   if d is not None:
  71     trunc = ''
  72     if not DBG.DATA_COMPLETE in debug_set:
  73       if len(d) > 64:
  74         d = d[0:64]
  75         trunc = '...'
  76     d = _hex_codec(d)[0].decode('ascii')
  77     msg += ' ' + d + trunc
  78   log.info('{dflag} {msgcore}', dflag=dflag, msgcore=msg)
  79
  80 @implementer(twisted.logger.ILogFilterPredicate)
  81 class LogNotBoringTwisted:
  82   def __call__(self, event):
  83     yes = twisted.logger.PredicateResult.yes
  84     no  = twisted.logger.PredicateResult.no
  85     try:
  86       if event.get('log_level') != LogLevel.info:
  87         return yes
  88       dflag = event.get('dflag')
  89       if dflag is False                            : return yes
  90       if dflag                         in debug_set: return yes
  91       if dflag is None and DBG.TWISTED in debug_set: return yes
  92       return no
  93     except Exception:
  94       print(traceback.format_exc(), file=org_stderr)
  95       return yes
  96
  97 #---------- default config ----------
  98
  99 defcfg = '''
 100 [DEFAULT]
 101 max_batch_down = 65536
 102 max_queue_time = 10
 103 target_requests_outstanding = 3
 104 http_timeout = 30
 105 http_timeout_grace = 5
 106 max_requests_outstanding = 6
 107 max_batch_up = 4000
 108 http_retry = 5
 109 port = 80
 110 vroutes = ''
 111
 112 #[server] or [<client>] overrides
 113 ipif = userv root ipif %(local)s,%(peer)s,%(mtu)s,slip %(rnets)s
 114
 115 # relating to virtual network
 116 mtu = 1500
 117
 118 [SERVER]
 119 server = SERVER
 120 # addrs = 127.0.0.1 ::1
 121 # url
 122
 123 # relating to virtual network
 124 vvnetwork = 172.24.230.192
 125 # vnetwork = <prefix>/<len>
 126 # vadd  r  = <ipaddr>
 127 # vrelay   = <ipaddr>
 128
 129
 130 # [<client-ip4-or-ipv6-address>]
 131 # password = <password>    # used by both, must match
 132
 133 [LIMIT]
 134 max_batch_down = 262144
 135 max_queue_time = 121
 136 http_timeout = 121
 137 target_requests_outstanding = 10
 138 '''
 139
 140 # these need to be defined here so that they can be imported by import *
 141 cfg = ConfigParser(strict=False)
 142 optparser = OptionParser()
 143
 144 _mimetrans = bytes.maketrans(b'-'+slip.esc, slip.esc+b'-')
 145 def mime_translate(s):
 146   # SLIP-encoded packets cannot contain ESC ESC.
 147   # Swap `-' and ESC.  The result cannot contain `--'
 148   return s.translate(_mimetrans)
 149
 150 class ConfigResults:
 151   def __init__(self):
 152     pass
 153   def __repr__(self):
 154     return 'ConfigResults('+repr(self.__dict__)+')'
 155
 156 def log_discard(packet, iface, saddr, daddr, why):
 157   log_debug(DBG.DROP,
 158             'discarded packet [%s] %s -> %s: %s' % (iface, saddr, daddr, why),
 159             d=packet)
 160
 161 #---------- packet parsing ----------
 162
 163 def packet_addrs(packet):
 164   version = packet[0] >> 4
 165   if version == 4:
 166     addrlen = 4
 167     saddroff = 3*4
 168     factory = ipaddress.IPv4Address
 169   elif version == 6:
 170     addrlen = 16
 171     saddroff = 2*4
 172     factory = ipaddress.IPv6Address
 173   else:
 174     raise ValueError('unsupported IP version %d' % version)
 175   saddr = factory(packet[ saddroff           : saddroff + addrlen   ])
 176   daddr = factory(packet[ saddroff + addrlen : saddroff + addrlen*2 ])
 177   return (saddr, daddr)
 178
 179 #---------- address handling ----------
 180
 181 def ipaddr(input):
 182   try:
 183     r = ipaddress.IPv4Address(input)
 184   except AddressValueError:
 185     r = ipaddress.IPv6Address(input)
 186   return r
 187
 188 def ipnetwork(input):
 189   try:
 190     r = ipaddress.IPv4Network(input)
 191   except NetworkValueError:
 192     r = ipaddress.IPv6Network(input)
 193   return r
 194
 195 #---------- ipif (SLIP) subprocess ----------
 196
 197 class SlipStreamDecoder():
 198   def __init__(self, desc, on_packet):
 199     self._buffer = b''
 200     self._on_packet = on_packet
 201     self._desc = desc
 202     self._log('__init__')
 203
 204   def _log(self, msg, **kwargs):
 205     log_debug(DBG.SLIP_FULL, 'slip %s: %s' % (self._desc, msg), **kwargs)
 206
 207   def inputdata(self, data):
 208     self._log('inputdata', d=data)
 209     data = self._buffer + data
 210     self._buffer = b''
 211     packets = slip.decode(data, True)
 212     self._buffer = packets.pop()
 213     for packet in packets:
 214       self._maybe_packet(packet)
 215     self._log('bufremain', d=self._buffer)
 216
 217   def _maybe_packet(self, packet):
 218     self._log('maybepacket', d=packet)
 219     if len(packet):
 220       self._on_packet(packet)
 221
 222   def flush(self):
 223     self._log('flush')
 224     data = self._buffer
 225     self._buffer = b''
 226     packets = slip.decode(data)
 227     assert(len(packets) == 1)
 228     self._maybe_packet(packets[0])
 229
 230 class _IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol):
 231   def __init__(self, router):
 232     self._router = router
 233     self._decoder = SlipStreamDecoder('ipif', self.slip_on_packet)
 234   def connectionMade(self): pass
 235   def outReceived(self, data):
 236     self._decoder.inputdata(data)
 237   def slip_on_packet(self, packet):
 238     (saddr, daddr) = packet_addrs(packet)
 239     if saddr.is_link_local or daddr.is_link_local:
 240       log_discard(packet, 'ipif', saddr, daddr, 'link-local')
 241       return
 242     self._router(packet, saddr, daddr)
 243   def processEnded(self, status):
 244     status.raiseException()
 245
 246 def start_ipif(command, router):
 247   ipif = _IpifProcessProtocol(router)
 248   reactor.spawnProcess(ipif,
 249                        '/bin/sh',['sh','-xc', command],
 250                        childFDs={0:'w', 1:'r', 2:2},
 251                        env=None)
 252   return ipif
 253
 254 def queue_inbound(ipif, packet):
 255   log_debug(DBG.FLOW, "queue_inbound", d=packet)
 256   ipif.transport.write(slip.delimiter)
 257   ipif.transport.write(slip.encode(packet))
 258   ipif.transport.write(slip.delimiter)
 259
 260 #---------- packet queue ----------
 261
 262 class PacketQueue():
 263   def __init__(self, desc, max_queue_time):
 264     self._desc = desc
 265     assert(desc + '')
 266     self._max_queue_time = max_queue_time
 267     self._pq = collections.deque() # packets
 268
 269   def _log(self, dflag, msg, **kwargs):
 270     log_debug(dflag, self._desc+' pq: '+msg, **kwargs)
 271
 272   def append(self, packet):
 273     self._log(DBG.QUEUE, 'append', d=packet)
 274     self._pq.append((time.monotonic(), packet))
 275
 276   def nonempty(self):
 277     self._log(DBG.QUEUE, 'nonempty ?')
 278     while True:
 279       try: (queuetime, packet) = self._pq[0]
 280       except IndexError:
 281         self._log(DBG.QUEUE, 'nonempty ? empty.')
 282         return False
 283
 284       age = time.monotonic() - queuetime
 285       if age > self._max_queue_time:
 286         # strip old packets off the front
 287         self._log(DBG.QUEUE, 'dropping (old)', d=packet)
 288         self._pq.popleft()
 289         continue
 290
 291       self._log(DBG.QUEUE, 'nonempty ? nonempty.')
 292       return True
 293
 294   def process(self, sizequery, moredata, max_batch):
 295     # sizequery() should return size of batch so far
 296     # moredata(s) should add s to batch
 297     self._log(DBG.QUEUE, 'process...')
 298     while True:
 299       try: (dummy, packet) = self._pq[0]
 300       except IndexError:
 301         self._log(DBG.QUEUE, 'process... empty')
 302         break
 303
 304       self._log(DBG.QUEUE_CTRL, 'process... packet', d=packet)
 305
 306       encoded = slip.encode(packet)
 307       sofar = sizequery()
 308
 309       self._log(DBG.QUEUE_CTRL,
 310                 'process... (sofar=%d, max=%d) encoded' % (sofar, max_batch),
 311                 d=encoded)
 312
 313       if sofar > 0:
 314         if sofar + len(slip.delimiter) + len(encoded) > max_batch:
 315           self._log(DBG.QUEUE_CTRL, 'process... overflow')
 316           break
 317         moredata(slip.delimiter)
 318
 319       moredata(encoded)
 320       self._pq.popleft()
 321
 322 #---------- error handling ----------
 323
 324 _crashing = False
 325
 326 def crash(err):
 327   global _crashing
 328   _crashing = True
 329   print('========== CRASH ==========', err,
 330         '===========================', file=sys.stderr)
 331   try: reactor.stop()
 332   except twisted.internet.error.ReactorNotRunning: pass
 333
 334 def crash_on_defer(defer):
 335   defer.addErrback(lambda err: crash(err))
 336
 337 def crash_on_critical(event):
 338   if event.get('log_level') >= LogLevel.critical:
 339     crash(twisted.logger.formatEvent(event))
 340
 341 #---------- config processing ----------
 342
 343 def _cfg_process_putatives():
 344   servers = { }
 345   clients = { }
 346   # maps from abstract object to canonical name for cs's
 347
 348   def putative(cmap, abstract, canoncs):
 349     try:
 350       current_canoncs = cmap[abstract]
 351     except KeyError:
 352       pass
 353     else:
 354       assert(current_canoncs == canoncs)
 355     cmap[abstract] = canoncs
 356
 357   server_pat = r'[-.0-9A-Za-z]+'
 358   client_pat = r'[.:0-9a-f]+'
 359   server_re = regexp.compile(server_pat)
 360   serverclient_re = regexp.compile(server_pat + r' ' + client_pat)
 361
 362   for cs in cfg.sections():
 363     if cs == 'LIMIT':
 364       # plan A "[LIMIT]"
 365       continue
 366
 367     try:
 368       # plan B "[<client>]" part 1
 369       ci = ipaddr(cs)
 370     except AddressValueError:
 371
 372       if server_re.fullmatch(cs):
 373         # plan C "[<servername>]"
 374         putative(servers, cs, cs)
 375         continue
 376
 377       if serverclient_re.fullmatch(cs):
 378         # plan D "[<servername> <client>]" part 1
 379         (pss,pcs) = cs.split(' ')
 380
 381         if pcs == 'LIMIT':
 382           # plan E "[<servername> LIMIT]"
 383           continue
 384
 385         try:
 386           # plan D "[<servername> <client>]" part 2
 387           ci = ipaddr(pc)
 388         except AddressValueError:
 389           # plan F "[<some thing we do not understand>]"
 390           # well, we ignore this
 391           print('warning: ignoring config section %s' % cs, file=sys.stderr)
 392           continue
 393
 394         else: # no AddressValueError
 395           # plan D "[<servername> <client]" part 3
 396           putative(clients, ci, pcs)
 397           putative(servers, pss, pss)
 398           continue
 399
 400     else: # no AddressValueError
 401       # plan B "[<client>" part 2
 402       putative(clients, ci, cs)
 403       continue
 404
 405   return (servers, clients)
 406
 407 def cfg_process_common(c, ss):
 408   c.mtu = cfg.getint(ss, 'mtu')
 409
 410 def cfg_process_saddrs(c, ss):
 411   class ServerAddr():
 412     def __init__(self, port, addrspec):
 413       self.port = port
 414       # also self.addr
 415       try:
 416         self.addr = ipaddress.IPv4Address(addrspec)
 417         self._endpointfactory = twisted.internet.endpoints.TCP4ServerEndpoint
 418         self._inurl = b'%s'
 419       except AddressValueError:
 420         self.addr = ipaddress.IPv6Address(addrspec)
 421         self._endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint
 422         self._inurl = b'[%s]'
 423     def make_endpoint(self):
 424       return self._endpointfactory(reactor, self.port, self.addr)
 425     def url(self):
 426       url = b'http://' + (self._inurl % str(self.addr).encode('ascii'))
 427       if self.port != 80: url += b':%d' % self.port
 428       url += b'/'
 429       return url
 430
 431   c.port = cfg.getint(ss,'port')
 432   c.saddrs = [ ]
 433   for addrspec in cfg.get(ss, 'addrs').split():
 434     sa = ServerAddr(c.port, addrspec)
 435     c.saddrs.append(sa)
 436
 437 def cfg_process_vnetwork(c, ss):
 438   c.vnetwork = ipnetwork(cfg.get(ss,'vnetwork'))
 439   if c.vnetwork.num_addresses < 3 + 2:
 440     raise ValueError('vnetwork needs at least 2^3 addresses')
 441
 442 def cfg_process_vaddr(c, ss):
 443   try:
 444     c.vaddr = cfg.get(ss,'vaddr')
 445   except NoOptionError:
 446     cfg_process_vnetwork(c, ss)
 447     c.vaddr = next(c.vnetwork.hosts())
 448
 449 def cfg_search_section(key,sections):
 450   for section in sections:
 451     if cfg.has_option(section, key):
 452       return section
 453   raise NoOptionError(key, repr(sections))
 454
 455 def cfg_search(getter,key,sections):
 456   section = cfg_search_section(key,sections)
 457   return getter(section, key)
 458
 459 def cfg_process_client_limited(cc,ss,sections,key):
 460   val = cfg_search(cfg.getint, key, sections)
 461   lim = cfg_search(cfg.getint, key, ['%s LIMIT' % ss, 'LIMIT'])
 462   cc.__dict__[key] = min(val,lim)
 463
 464 def cfg_process_client_common(cc,ss,cs,ci):
 465   # returns sections to search in, iff password is defined, otherwise None
 466   cc.ci = ci
 467
 468   sections = ['%s %s' % (ss,cs),
 469               cs,
 470               ss,
 471               'DEFAULT']
 472
 473   try: pwsection = cfg_search_section('password', sections)
 474   except NoOptionError: return None
 475
 476   pw = cfg.get(pwsection, 'password')
 477   cc.password = pw.encode('utf-8')
 478
 479   cfg_process_client_limited(cc,ss,sections,'target_requests_outstanding')
 480   cfg_process_client_limited(cc,ss,sections,'http_timeout')
 481
 482   return sections
 483
 484 def cfg_process_ipif(c, sections, varmap):
 485   for d, s in varmap:
 486     try: v = getattr(c, s)
 487     except AttributeError: continue
 488     setattr(c, d, v)
 489
 490   #print('CFGIPIF',repr((varmap, sections, c.__dict__)),file=sys.stderr)
 491
 492   section = cfg_search_section('ipif', sections)
 493   c.ipif_command = cfg.get(section,'ipif', vars=c.__dict__)
 494
 495 #---------- startup ----------
 496
 497 def common_startup(process_cfg):
 498   # calls process_cfg(putative_clients, putative_servers)
 499
 500   # ConfigParser hates #-comments after values
 501   trailingcomments_re = regexp.compile(r'#.*')
 502   cfg.read_string(trailingcomments_re.sub('', defcfg))
 503   need_defcfg = True
 504
 505   def readconfig(pathname, mandatory=True):
 506     def log(m, p=pathname):
 507       if not DBG.CONFIG in debug_set: return
 508       print('DBG.CONFIG: %s: %s' % (m, pathname))
 509
 510     try:
 511       files = os.listdir(pathname)
 512
 513     except FileNotFoundError:
 514       if mandatory: raise
 515       log('skipped')
 516       return
 517
 518     except NotADirectoryError:
 519       cfg.read(pathname)
 520       log('read file')
 521       return
 522
 523     # is a directory
 524     log('directory')
 525     re = regexp.compile('[^-A-Za-z0-9_]')
 526     for f in os.listdir(cdir):
 527       if re.search(f): continue
 528       subpath = pathname + '/' + f
 529       try:
 530         os.stat(subpath)
 531       except FileNotFoundError:
 532         log('entry skipped', subpath)
 533         continue
 534       cfg.read(subpath)
 535       log('entry read', subpath)
 536
 537   def oc_config(od,os, value, op):
 538     nonlocal need_defcfg
 539     need_defcfg = False
 540     readconfig(value)
 541
 542   def dfs_less_detailed(dl):
 543     return [df for df in DBG.iterconstants() if df <= dl]
 544
 545   def ds_default(od,os,dl,op):
 546     global debug_set
 547     debug_set = set(dfs_less_detailed(debug_def_detail))
 548
 549   def ds_select(od,os, spec, op):
 550     for it in spec.split(','):
 551
 552       if it.startswith('-'):
 553         mutator = debug_set.discard
 554         it = it[1:]
 555       else:
 556         mutator = debug_set.add
 557
 558       if it == '+':
 559         dfs = DBG.iterconstants()
 560
 561       else:
 562         if it.endswith('+'):
 563           mapper = dfs_less_detailed
 564           it = it[0:len(it)-1]
 565         else:
 566           mapper = lambda x: [x]
 567
 568           try:
 569             dfspec = DBG.lookupByName(it)
 570           except ValueError:
 571             optparser.error('unknown debug flag %s in --debug-select' % it)
 572
 573         dfs = mapper(dfspec)
 574
 575       for df in dfs:
 576         mutator(df)
 577
 578   optparser.add_option('-D', '--debug',
 579                        nargs=0,
 580                        action='callback',
 581                        help='enable default debug (to stdout)',
 582                        callback= ds_default)
 583
 584   optparser.add_option('--debug-select',
 585                        nargs=1,
 586                        type='string',
 587                        metavar='[-]DFLAG[+]|[-]+,...',
 588                        help=
 589 '''enable (`-': disable) each specified DFLAG;
 590 `+': do same for all "more interesting" DFLAGSs;
 591 just `+': all DFLAGs.
 592   DFLAGS: ''' + ' '.join([df.name for df in DBG.iterconstants()]),
 593                        action='callback',
 594                        callback= ds_select)
 595
 596   optparser.add_option('-c', '--config',
 597                        nargs=1,
 598                        type='string',
 599                        metavar='CONFIGFILE',
 600                        dest='configfile',
 601                        action='callback',
 602                        callback= oc_config)
 603
 604   (opts, args) = optparser.parse_args()
 605   if len(args): optparser.error('no non-option arguments please')
 606
 607   if need_defcfg:
 608     readconfig('/etc/hippotat/config',   False)
 609     readconfig('/etc/hippotat/config.d', False)
 610
 611   try:
 612     (pss, pcs) = _cfg_process_putatives()
 613     process_cfg(pss, pcs)
 614   except (configparser.Error, ValueError):
 615     traceback.print_exc(file=sys.stderr)
 616     print('\nInvalid configuration, giving up.', file=sys.stderr)
 617     sys.exit(12)
 618
 619   #print(repr(debug_set), file=sys.stderr)
 620
 621   log_formatter = twisted.logger.formatEventAsClassicLogText
 622   stdout_obs = twisted.logger.FileLogObserver(sys.stdout, log_formatter)
 623   stderr_obs = twisted.logger.FileLogObserver(sys.stderr, log_formatter)
 624   pred = twisted.logger.LogLevelFilterPredicate(LogLevel.error)
 625   stdsomething_obs = twisted.logger.FilteringLogObserver(
 626     stderr_obs, [pred], stdout_obs
 627   )
 628   log_observer = twisted.logger.FilteringLogObserver(
 629     stdsomething_obs, [LogNotBoringTwisted()]
 630   )
 631   #log_observer = stdsomething_obs
 632   twisted.logger.globalLogBeginner.beginLoggingTo(
 633     [ log_observer, crash_on_critical ]
 634     )
 635
 636 def common_run():
 637   log_debug(DBG.INIT, 'entering reactor')
 638   if not _crashing: reactor.run()
 639   print('CRASHED (end)', file=sys.stderr)