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

   1 # -*- python -*-
   2 #
   3 # Hippotat - Asinine IP Over HTTP program
   4 # hippotatlib/__init__.py - common library code
   5 #
   6 # Copyright 2017 Ian Jackson
   7 #
   8 # This program is free software: you can redistribute it and/or modify
   9 # it under the terms of the GNU Affero General Public License as
  10 # published by the Free Software Foundation, either version 3 of the
  11 # License, or (at your option) any later version, with the "CAF Login
  12 # Exception" as published by Ian Jackson (version 2, or at your option
  13 # any later version) as an Additional Permission.
  14 #
  15 # This program is distributed in the hope that it will be useful,
  16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 # GNU Affero General Public License for more details.
  19 #
  20 # You should have received a copy of the GNU Affero General Public
  21 # License and the CAF Login Exception along with this program, in the
  22 # file AGPLv3+CAFv2.  If not, email Ian Jackson
  23 # <ijackson@chiark.greenend.org.uk>.
  24
  25 import signal
  26 signal.signal(signal.SIGINT, signal.SIG_DFL)
  27
  28 import sys
  29 import os
  30
  31 from zope.interface import implementer
  32
  33 import twisted
  34 from twisted.internet import reactor
  35 import twisted.internet.endpoints
  36 import twisted.logger
  37 from twisted.logger import LogLevel
  38 import twisted.python.constants
  39 from twisted.python.constants import NamedConstant
  40
  41 import ipaddress
  42 from ipaddress import AddressValueError
  43
  44 from optparse import OptionParser
  45 import configparser
  46 from configparser import ConfigParser
  47 from configparser import NoOptionError
  48
  49 from functools import partial
  50
  51 import collections
  52 import time
  53 import codecs
  54 import traceback
  55
  56 import re as regexp
  57
  58 import hippotatlib.slip as slip
  59
  60 class DBG(twisted.python.constants.Names):
  61   INIT = NamedConstant()
  62   CONFIG = NamedConstant()
  63   ROUTE = NamedConstant()
  64   DROP = NamedConstant()
  65   OWNSOURCE = NamedConstant()
  66   FLOW = NamedConstant()
  67   HTTP = NamedConstant()
  68   TWISTED = NamedConstant()
  69   QUEUE = NamedConstant()
  70   HTTP_CTRL = NamedConstant()
  71   QUEUE_CTRL = NamedConstant()
  72   HTTP_FULL = NamedConstant()
  73   CTRL_DUMP = NamedConstant()
  74   SLIP_FULL = NamedConstant()
  75   DATA_COMPLETE = NamedConstant()
  76
  77 _hex_codec = codecs.getencoder('hex_codec')
  78
  79 #---------- logging ----------
  80
  81 org_stderr = sys.stderr
  82
  83 log = twisted.logger.Logger()
  84
  85 debug_set = set()
  86 debug_def_detail = DBG.HTTP
  87
  88 def log_debug(dflag, msg, idof=None, d=None):
  89   if dflag not in debug_set: return
  90   #print('---------------->',repr((dflag, msg, idof, d)), file=sys.stderr)
  91   if idof is not None:
  92     msg = '[%#x] %s' % (id(idof), msg)
  93   if d is not None:
  94     trunc = ''
  95     if not DBG.DATA_COMPLETE in debug_set:
  96       if len(d) > 64:
  97         d = d[0:64]
  98         trunc = '...'
  99     d = _hex_codec(d)[0].decode('ascii')
 100     msg += ' ' + d + trunc
 101   log.info('{dflag} {msgcore}', dflag=dflag, msgcore=msg)
 102
 103 @implementer(twisted.logger.ILogFilterPredicate)
 104 class LogNotBoringTwisted:
 105   def __call__(self, event):
 106     yes = twisted.logger.PredicateResult.yes
 107     no  = twisted.logger.PredicateResult.no
 108     try:
 109       if event.get('log_level') != LogLevel.info:
 110         return yes
 111       dflag = event.get('dflag')
 112       if dflag is False                            : return yes
 113       if dflag                         in debug_set: return yes
 114       if dflag is None and DBG.TWISTED in debug_set: return yes
 115       return no
 116     except Exception:
 117       print(traceback.format_exc(), file=org_stderr)
 118       return yes
 119
 120 #---------- default config ----------
 121
 122 defcfg = '''
 123 [DEFAULT]
 124 max_batch_down = 65536
 125 max_queue_time = 10
 126 target_requests_outstanding = 3
 127 http_timeout = 30
 128 http_timeout_grace = 5
 129 max_requests_outstanding = 6
 130 max_batch_up = 4000
 131 http_retry = 5
 132 port = 80
 133 vroutes = ''
 134
 135 #[server] or [<client>] overrides
 136 ipif = userv root ipif %(local)s,%(peer)s,%(mtu)s,slip %(rnets)s
 137
 138 # relating to virtual network
 139 mtu = 1500
 140
 141 [SERVER]
 142 server = SERVER
 143 # addrs = 127.0.0.1 ::1
 144 # url
 145
 146 # relating to virtual network
 147 vvnetwork = 172.24.230.192
 148 # vnetwork = <prefix>/<len>
 149 # vadd  r  = <ipaddr>
 150 # vrelay   = <ipaddr>
 151
 152
 153 # [<client-ip4-or-ipv6-address>]
 154 # password = <password>    # used by both, must match
 155
 156 [LIMIT]
 157 max_batch_down = 262144
 158 max_queue_time = 121
 159 http_timeout = 121
 160 target_requests_outstanding = 10
 161 '''
 162
 163 # these need to be defined here so that they can be imported by import *
 164 cfg = ConfigParser(strict=False)
 165 optparser = OptionParser()
 166
 167 _mimetrans = bytes.maketrans(b'-'+slip.esc, slip.esc+b'-')
 168 def mime_translate(s):
 169   # SLIP-encoded packets cannot contain ESC ESC.
 170   # Swap `-' and ESC.  The result cannot contain `--'
 171   return s.translate(_mimetrans)
 172
 173 class ConfigResults:
 174   def __init__(self):
 175     pass
 176   def __repr__(self):
 177     return 'ConfigResults('+repr(self.__dict__)+')'
 178
 179 def log_discard(packet, iface, saddr, daddr, why):
 180   log_debug(DBG.DROP,
 181             'discarded packet [%s] %s -> %s: %s' % (iface, saddr, daddr, why),
 182             d=packet)
 183
 184 #---------- packet parsing ----------
 185
 186 def packet_addrs(packet):
 187   version = packet[0] >> 4
 188   if version == 4:
 189     addrlen = 4
 190     saddroff = 3*4
 191     factory = ipaddress.IPv4Address
 192   elif version == 6:
 193     addrlen = 16
 194     saddroff = 2*4
 195     factory = ipaddress.IPv6Address
 196   else:
 197     raise ValueError('unsupported IP version %d' % version)
 198   saddr = factory(packet[ saddroff           : saddroff + addrlen   ])
 199   daddr = factory(packet[ saddroff + addrlen : saddroff + addrlen*2 ])
 200   return (saddr, daddr)
 201
 202 #---------- address handling ----------
 203
 204 def ipaddr(input):
 205   try:
 206     r = ipaddress.IPv4Address(input)
 207   except AddressValueError:
 208     r = ipaddress.IPv6Address(input)
 209   return r
 210
 211 def ipnetwork(input):
 212   try:
 213     r = ipaddress.IPv4Network(input)
 214   except NetworkValueError:
 215     r = ipaddress.IPv6Network(input)
 216   return r
 217
 218 #---------- ipif (SLIP) subprocess ----------
 219
 220 class SlipStreamDecoder():
 221   def __init__(self, desc, on_packet):
 222     self._buffer = b''
 223     self._on_packet = on_packet
 224     self._desc = desc
 225     self._log('__init__')
 226
 227   def _log(self, msg, **kwargs):
 228     log_debug(DBG.SLIP_FULL, 'slip %s: %s' % (self._desc, msg), **kwargs)
 229
 230   def inputdata(self, data):
 231     self._log('inputdata', d=data)
 232     data = self._buffer + data
 233     self._buffer = b''
 234     packets = slip.decode(data, True)
 235     self._buffer = packets.pop()
 236     for packet in packets:
 237       self._maybe_packet(packet)
 238     self._log('bufremain', d=self._buffer)
 239
 240   def _maybe_packet(self, packet):
 241     self._log('maybepacket', d=packet)
 242     if len(packet):
 243       self._on_packet(packet)
 244
 245   def flush(self):
 246     self._log('flush')
 247     data = self._buffer
 248     self._buffer = b''
 249     packets = slip.decode(data)
 250     assert(len(packets) == 1)
 251     self._maybe_packet(packets[0])
 252
 253 class _IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol):
 254   def __init__(self, router):
 255     self._router = router
 256     self._decoder = SlipStreamDecoder('ipif', self.slip_on_packet)
 257   def connectionMade(self): pass
 258   def outReceived(self, data):
 259     self._decoder.inputdata(data)
 260   def slip_on_packet(self, packet):
 261     (saddr, daddr) = packet_addrs(packet)
 262     if saddr.is_link_local or daddr.is_link_local:
 263       log_discard(packet, 'ipif', saddr, daddr, 'link-local')
 264       return
 265     self._router(packet, saddr, daddr)
 266   def processEnded(self, status):
 267     status.raiseException()
 268
 269 def start_ipif(command, router):
 270   ipif = _IpifProcessProtocol(router)
 271   reactor.spawnProcess(ipif,
 272                        '/bin/sh',['sh','-xc', command],
 273                        childFDs={0:'w', 1:'r', 2:2},
 274                        env=None)
 275   return ipif
 276
 277 def queue_inbound(ipif, packet):
 278   log_debug(DBG.FLOW, "queue_inbound", d=packet)
 279   ipif.transport.write(slip.delimiter)
 280   ipif.transport.write(slip.encode(packet))
 281   ipif.transport.write(slip.delimiter)
 282
 283 #---------- packet queue ----------
 284
 285 class PacketQueue():
 286   def __init__(self, desc, max_queue_time):
 287     self._desc = desc
 288     assert(desc + '')
 289     self._max_queue_time = max_queue_time
 290     self._pq = collections.deque() # packets
 291
 292   def _log(self, dflag, msg, **kwargs):
 293     log_debug(dflag, self._desc+' pq: '+msg, **kwargs)
 294
 295   def append(self, packet):
 296     self._log(DBG.QUEUE, 'append', d=packet)
 297     self._pq.append((time.monotonic(), packet))
 298
 299   def nonempty(self):
 300     self._log(DBG.QUEUE, 'nonempty ?')
 301     while True:
 302       try: (queuetime, packet) = self._pq[0]
 303       except IndexError:
 304         self._log(DBG.QUEUE, 'nonempty ? empty.')
 305         return False
 306
 307       age = time.monotonic() - queuetime
 308       if age > self._max_queue_time:
 309         # strip old packets off the front
 310         self._log(DBG.QUEUE, 'dropping (old)', d=packet)
 311         self._pq.popleft()
 312         continue
 313
 314       self._log(DBG.QUEUE, 'nonempty ? nonempty.')
 315       return True
 316
 317   def process(self, sizequery, moredata, max_batch):
 318     # sizequery() should return size of batch so far
 319     # moredata(s) should add s to batch
 320     self._log(DBG.QUEUE, 'process...')
 321     while True:
 322       try: (dummy, packet) = self._pq[0]
 323       except IndexError:
 324         self._log(DBG.QUEUE, 'process... empty')
 325         break
 326
 327       self._log(DBG.QUEUE_CTRL, 'process... packet', d=packet)
 328
 329       encoded = slip.encode(packet)
 330       sofar = sizequery()
 331
 332       self._log(DBG.QUEUE_CTRL,
 333                 'process... (sofar=%d, max=%d) encoded' % (sofar, max_batch),
 334                 d=encoded)
 335
 336       if sofar > 0:
 337         if sofar + len(slip.delimiter) + len(encoded) > max_batch:
 338           self._log(DBG.QUEUE_CTRL, 'process... overflow')
 339           break
 340         moredata(slip.delimiter)
 341
 342       moredata(encoded)
 343       self._pq.popleft()
 344
 345 #---------- error handling ----------
 346
 347 _crashing = False
 348
 349 def crash(err):
 350   global _crashing
 351   _crashing = True
 352   print('========== CRASH ==========', err,
 353         '===========================', file=sys.stderr)
 354   try: reactor.stop()
 355   except twisted.internet.error.ReactorNotRunning: pass
 356
 357 def crash_on_defer(defer):
 358   defer.addErrback(lambda err: crash(err))
 359
 360 def crash_on_critical(event):
 361   if event.get('log_level') >= LogLevel.critical:
 362     crash(twisted.logger.formatEvent(event))
 363
 364 #---------- config processing ----------
 365
 366 def _cfg_process_putatives():
 367   servers = { }
 368   clients = { }
 369   # maps from abstract object to canonical name for cs's
 370
 371   def putative(cmap, abstract, canoncs):
 372     try:
 373       current_canoncs = cmap[abstract]
 374     except KeyError:
 375       pass
 376     else:
 377       assert(current_canoncs == canoncs)
 378     cmap[abstract] = canoncs
 379
 380   server_pat = r'[-.0-9A-Za-z]+'
 381   client_pat = r'[.:0-9a-f]+'
 382   server_re = regexp.compile(server_pat)
 383   serverclient_re = regexp.compile(server_pat + r' ' + client_pat)
 384
 385   for cs in cfg.sections():
 386     if cs == 'LIMIT':
 387       # plan A "[LIMIT]"
 388       continue
 389
 390     try:
 391       # plan B "[<client>]" part 1
 392       ci = ipaddr(cs)
 393     except AddressValueError:
 394
 395       if server_re.fullmatch(cs):
 396         # plan C "[<servername>]"
 397         putative(servers, cs, cs)
 398         continue
 399
 400       if serverclient_re.fullmatch(cs):
 401         # plan D "[<servername> <client>]" part 1
 402         (pss,pcs) = cs.split(' ')
 403
 404         if pcs == 'LIMIT':
 405           # plan E "[<servername> LIMIT]"
 406           continue
 407
 408         try:
 409           # plan D "[<servername> <client>]" part 2
 410           ci = ipaddr(pc)
 411         except AddressValueError:
 412           # plan F "[<some thing we do not understand>]"
 413           # well, we ignore this
 414           print('warning: ignoring config section %s' % cs, file=sys.stderr)
 415           continue
 416
 417         else: # no AddressValueError
 418           # plan D "[<servername> <client]" part 3
 419           putative(clients, ci, pcs)
 420           putative(servers, pss, pss)
 421           continue
 422
 423     else: # no AddressValueError
 424       # plan B "[<client>" part 2
 425       putative(clients, ci, cs)
 426       continue
 427
 428   return (servers, clients)
 429
 430 def cfg_process_common(c, ss):
 431   c.mtu = cfg.getint(ss, 'mtu')
 432
 433 def cfg_process_saddrs(c, ss):
 434   class ServerAddr():
 435     def __init__(self, port, addrspec):
 436       self.port = port
 437       # also self.addr
 438       try:
 439         self.addr = ipaddress.IPv4Address(addrspec)
 440         self._endpointfactory = twisted.internet.endpoints.TCP4ServerEndpoint
 441         self._inurl = b'%s'
 442       except AddressValueError:
 443         self.addr = ipaddress.IPv6Address(addrspec)
 444         self._endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint
 445         self._inurl = b'[%s]'
 446     def make_endpoint(self):
 447       return self._endpointfactory(reactor, self.port, self.addr)
 448     def url(self):
 449       url = b'http://' + (self._inurl % str(self.addr).encode('ascii'))
 450       if self.port != 80: url += b':%d' % self.port
 451       url += b'/'
 452       return url
 453
 454   c.port = cfg.getint(ss,'port')
 455   c.saddrs = [ ]
 456   for addrspec in cfg.get(ss, 'addrs').split():
 457     sa = ServerAddr(c.port, addrspec)
 458     c.saddrs.append(sa)
 459
 460 def cfg_process_vnetwork(c, ss):
 461   c.vnetwork = ipnetwork(cfg.get(ss,'vnetwork'))
 462   if c.vnetwork.num_addresses < 3 + 2:
 463     raise ValueError('vnetwork needs at least 2^3 addresses')
 464
 465 def cfg_process_vaddr(c, ss):
 466   try:
 467     c.vaddr = cfg.get(ss,'vaddr')
 468   except NoOptionError:
 469     cfg_process_vnetwork(c, ss)
 470     c.vaddr = next(c.vnetwork.hosts())
 471
 472 def cfg_search_section(key,sections):
 473   for section in sections:
 474     if cfg.has_option(section, key):
 475       return section
 476   raise NoOptionError(key, repr(sections))
 477
 478 def cfg_search(getter,key,sections):
 479   section = cfg_search_section(key,sections)
 480   return getter(section, key)
 481
 482 def cfg_process_client_limited(cc,ss,sections,key):
 483   val = cfg_search(cfg.getint, key, sections)
 484   lim = cfg_search(cfg.getint, key, ['%s LIMIT' % ss, 'LIMIT'])
 485   cc.__dict__[key] = min(val,lim)
 486
 487 def cfg_process_client_common(cc,ss,cs,ci):
 488   # returns sections to search in, iff password is defined, otherwise None
 489   cc.ci = ci
 490
 491   sections = ['%s %s' % (ss,cs),
 492               cs,
 493               ss,
 494               'DEFAULT']
 495
 496   try: pwsection = cfg_search_section('password', sections)
 497   except NoOptionError: return None
 498
 499   pw = cfg.get(pwsection, 'password')
 500   cc.password = pw.encode('utf-8')
 501
 502   cfg_process_client_limited(cc,ss,sections,'target_requests_outstanding')
 503   cfg_process_client_limited(cc,ss,sections,'http_timeout')
 504
 505   return sections
 506
 507 def cfg_process_ipif(c, sections, varmap):
 508   for d, s in varmap:
 509     try: v = getattr(c, s)
 510     except AttributeError: continue
 511     setattr(c, d, v)
 512
 513   #print('CFGIPIF',repr((varmap, sections, c.__dict__)),file=sys.stderr)
 514
 515   section = cfg_search_section('ipif', sections)
 516   c.ipif_command = cfg.get(section,'ipif', vars=c.__dict__)
 517
 518 #---------- startup ----------
 519
 520 def common_startup(process_cfg):
 521   # calls process_cfg(putative_clients, putative_servers)
 522
 523   # ConfigParser hates #-comments after values
 524   trailingcomments_re = regexp.compile(r'#.*')
 525   cfg.read_string(trailingcomments_re.sub('', defcfg))
 526   need_defcfg = True
 527
 528   def readconfig(pathname, mandatory=True):
 529     def log(m, p=pathname):
 530       if not DBG.CONFIG in debug_set: return
 531       print('DBG.CONFIG: %s: %s' % (m, pathname))
 532
 533     try:
 534       files = os.listdir(pathname)
 535
 536     except FileNotFoundError:
 537       if mandatory: raise
 538       log('skipped')
 539       return
 540
 541     except NotADirectoryError:
 542       cfg.read(pathname)
 543       log('read file')
 544       return
 545
 546     # is a directory
 547     log('directory')
 548     re = regexp.compile('[^-A-Za-z0-9_]')
 549     for f in os.listdir(cdir):
 550       if re.search(f): continue
 551       subpath = pathname + '/' + f
 552       try:
 553         os.stat(subpath)
 554       except FileNotFoundError:
 555         log('entry skipped', subpath)
 556         continue
 557       cfg.read(subpath)
 558       log('entry read', subpath)
 559
 560   def oc_config(od,os, value, op):
 561     nonlocal need_defcfg
 562     need_defcfg = False
 563     readconfig(value)
 564
 565   def dfs_less_detailed(dl):
 566     return [df for df in DBG.iterconstants() if df <= dl]
 567
 568   def ds_default(od,os,dl,op):
 569     global debug_set
 570     debug_set = set(dfs_less_detailed(debug_def_detail))
 571
 572   def ds_select(od,os, spec, op):
 573     for it in spec.split(','):
 574
 575       if it.startswith('-'):
 576         mutator = debug_set.discard
 577         it = it[1:]
 578       else:
 579         mutator = debug_set.add
 580
 581       if it == '+':
 582         dfs = DBG.iterconstants()
 583
 584       else:
 585         if it.endswith('+'):
 586           mapper = dfs_less_detailed
 587           it = it[0:len(it)-1]
 588         else:
 589           mapper = lambda x: [x]
 590
 591           try:
 592             dfspec = DBG.lookupByName(it)
 593           except ValueError:
 594             optparser.error('unknown debug flag %s in --debug-select' % it)
 595
 596         dfs = mapper(dfspec)
 597
 598       for df in dfs:
 599         mutator(df)
 600
 601   optparser.add_option('-D', '--debug',
 602                        nargs=0,
 603                        action='callback',
 604                        help='enable default debug (to stdout)',
 605                        callback= ds_default)
 606
 607   optparser.add_option('--debug-select',
 608                        nargs=1,
 609                        type='string',
 610                        metavar='[-]DFLAG[+]|[-]+,...',
 611                        help=
 612 '''enable (`-': disable) each specified DFLAG;
 613 `+': do same for all "more interesting" DFLAGSs;
 614 just `+': all DFLAGs.
 615   DFLAGS: ''' + ' '.join([df.name for df in DBG.iterconstants()]),
 616                        action='callback',
 617                        callback= ds_select)
 618
 619   optparser.add_option('-c', '--config',
 620                        nargs=1,
 621                        type='string',
 622                        metavar='CONFIGFILE',
 623                        dest='configfile',
 624                        action='callback',
 625                        callback= oc_config)
 626
 627   (opts, args) = optparser.parse_args()
 628   if len(args): optparser.error('no non-option arguments please')
 629
 630   if need_defcfg:
 631     readconfig('/etc/hippotat/config',   False)
 632     readconfig('/etc/hippotat/config.d', False)
 633
 634   try:
 635     (pss, pcs) = _cfg_process_putatives()
 636     process_cfg(pss, pcs)
 637   except (configparser.Error, ValueError):
 638     traceback.print_exc(file=sys.stderr)
 639     print('\nInvalid configuration, giving up.', file=sys.stderr)
 640     sys.exit(12)
 641
 642   #print(repr(debug_set), file=sys.stderr)
 643
 644   log_formatter = twisted.logger.formatEventAsClassicLogText
 645   stdout_obs = twisted.logger.FileLogObserver(sys.stdout, log_formatter)
 646   stderr_obs = twisted.logger.FileLogObserver(sys.stderr, log_formatter)
 647   pred = twisted.logger.LogLevelFilterPredicate(LogLevel.error)
 648   stdsomething_obs = twisted.logger.FilteringLogObserver(
 649     stderr_obs, [pred], stdout_obs
 650   )
 651   log_observer = twisted.logger.FilteringLogObserver(
 652     stdsomething_obs, [LogNotBoringTwisted()]
 653   )
 654   #log_observer = stdsomething_obs
 655   twisted.logger.globalLogBeginner.beginLoggingTo(
 656     [ log_observer, crash_on_critical ]
 657     )
 658
 659 def common_run():
 660   log_debug(DBG.INIT, 'entering reactor')
 661   if not _crashing: reactor.run()
 662   print('CRASHED (end)', file=sys.stderr)