mdw@git.distorted.org.uk Git - tripe/blob - svc/connect.in

   1 #! @PYTHON@
   2 ### -*-python-*-
   3 ###
   4 ### Connect to remote peers, and keep track of them
   5 ###
   6 ### (c) 2007 Straylight/Edgeware
   7 ###
   8
   9 ###----- Licensing notice ---------------------------------------------------
  10 ###
  11 ### This file is part of Trivial IP Encryption (TrIPE).
  12 ###
  13 ### TrIPE is free software: you can redistribute it and/or modify it under
  14 ### the terms of the GNU General Public License as published by the Free
  15 ### Software Foundation; either version 3 of the License, or (at your
  16 ### option) any later version.
  17 ###
  18 ### TrIPE is distributed in the hope that it will be useful, but WITHOUT
  19 ### ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  20 ### FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  21 ### for more details.
  22 ###
  23 ### You should have received a copy of the GNU General Public License
  24 ### along with TrIPE.  If not, see <https://www.gnu.org/licenses/>.
  25
  26 VERSION = '@VERSION@'
  27
  28 ###--------------------------------------------------------------------------
  29 ### External dependencies.
  30
  31 from optparse import OptionParser
  32 import tripe as T
  33 import os as OS
  34 import signal as SIG
  35 import errno as E
  36 from math import sqrt
  37 import cdb as CDB
  38 import mLib as M
  39 import re as RX
  40 import sys as SYS
  41 from time import time
  42 import subprocess as PROC
  43
  44 S = T.svcmgr
  45
  46 ###--------------------------------------------------------------------------
  47 ### Running auxiliary commands.
  48
  49 class SelLineQueue (M.SelLineBuffer):
  50   """Glues the select-line-buffer into the coroutine queue system."""
  51
  52   def __new__(cls, file, queue, tag, kind):
  53     """See __init__ for documentation."""
  54     return M.SelLineBuffer.__new__(cls, file.fileno())
  55
  56   def __init__(me, file, queue, tag, kind):
  57     """
  58     Initialize a new line-reading adaptor.
  59
  60     The adaptor reads lines from FILE.  Each line is inserted as a message of
  61     the stated KIND, bearing the TAG, into the QUEUE.  End-of-file is
  62     represented as None.
  63     """
  64     me._q = queue
  65     me._file = file
  66     me._tag = tag
  67     me._kind = kind
  68     me.enable()
  69
  70   @T._callback
  71   def line(me, line):
  72     me._q.put((me._tag, me._kind, line))
  73
  74   @T._callback
  75   def eof(me):
  76     me.disable()
  77     me._q.put((me._tag, me._kind, None))
  78
  79 class ErrorWatch (T.Coroutine):
  80   """
  81   An object which watches stderr streams for errors and converts them into
  82   warnings of the form
  83
  84     WARN connect INFO stderr LINE
  85
  86   The INFO is a list of tokens associated with the file when it was
  87   registered.
  88
  89   Usually there is a single ErrorWatch object, called errorwatch.
  90   """
  91
  92   def __init__(me):
  93     """Initialization: there are no arguments."""
  94     T.Coroutine.__init__(me)
  95     me._q = T.Queue()
  96     me._map = {}
  97     me._seq = 1
  98
  99   def watch(me, file, info):
 100     """
 101     Adds FILE to the collection of files to watch.
 102
 103     INFO will be written in the warning messages from this FILE.  Returns a
 104     sequence number which can be used to unregister the file again.
 105     """
 106     seq = me._seq
 107     me._seq += 1
 108     me._map[seq] = info, SelLineQueue(file, me._q, seq, 'stderr')
 109     return seq
 110
 111   def unwatch(me, seq):
 112     """Stop watching the file with sequence number SEQ."""
 113     del me._map[seq]
 114     return me
 115
 116   def run(me):
 117     """
 118     Coroutine function: read items from the queue and report them.
 119
 120     Unregisters files automatically when they reach EOF.
 121     """
 122     while True:
 123       seq, _, line = me._q.get()
 124       if line is None:
 125         me.unwatch(seq)
 126       else:
 127         S.warn(*['connect'] + me._map[seq][0] + ['stderr', line])
 128
 129 def dbwatch():
 130   """
 131   Coroutine function: wake up every minute and notice changes to the
 132   database.  When a change happens, tell the Pinger (q.v.) to rescan its
 133   peers.
 134   """
 135   cr = T.Coroutine.getcurrent()
 136   main = cr.parent
 137   fw = M.FWatch(opts.cdb)
 138   while True:
 139     timer = M.SelTimer(time() + 60, lambda: cr.switch())
 140     main.switch()
 141     if fw.update():
 142       pinger.rescan(False)
 143       S.notify('connect', 'peerdb-update')
 144
 145 class ChildWatch (M.SelSignal):
 146   """
 147   An object which watches for specified processes exiting and reports
 148   terminations by writing items of the form (TAG, 'exit', RESULT) to a queue.
 149
 150   There is usually only one ChildWatch object, called childwatch.
 151   """
 152
 153   def __new__(cls):
 154     """Initialize the child-watcher."""
 155     return M.SelSignal.__new__(cls, SIG.SIGCHLD)
 156
 157   def __init__(me):
 158     """Initialize the child-watcher."""
 159     me._pid = {}
 160     me.enable()
 161
 162   def watch(me, pid, queue, tag):
 163     """
 164     Register PID as a child to watch.  If it exits, write (TAG, 'exit', CODE)
 165     to the QUEUE, where CODE is one of
 166
 167       * None (successful termination)
 168       * ['exit-nonzero', CODE] (CODE is a string!)
 169       * ['exit-signal', 'S' + CODE] (CODE is the signal number as a string)
 170       * ['exit-unknown', STATUS] (STATUS is the entire exit status, in hex)
 171     """
 172     me._pid[pid] = queue, tag
 173     return me
 174
 175   def unwatch(me, pid):
 176     """Unregister PID as a child to watch."""
 177     del me._pid[pid]
 178     return me
 179
 180   @T._callback
 181   def signalled(me):
 182     """
 183     Called when child processes exit: collect exit statuses and report
 184     failures.
 185     """
 186     while True:
 187       try:
 188         pid, status = OS.waitpid(-1, OS.WNOHANG)
 189       except OSError, exc:
 190         if exc.errno == E.ECHILD:
 191           break
 192       if pid == 0:
 193         break
 194       if pid not in me._pid:
 195         continue
 196       queue, tag = me._pid[pid]
 197       if OS.WIFEXITED(status):
 198         exit = OS.WEXITSTATUS(status)
 199         if exit == 0:
 200           code = None
 201         else:
 202           code = ['exit-nonzero', str(exit)]
 203       elif OS.WIFSIGNALED(status):
 204         code = ['exit-signal', 'S' + str(OS.WTERMSIG(status))]
 205       else:
 206         code = ['exit-unknown', hex(status)]
 207       queue.put((tag, 'exit', code))
 208
 209 class Command (object):
 210   """
 211   Represents a running command.
 212
 213   This class is the main interface to the machery provided by the ChildWatch
 214   and ErrorWatch objects.  See also potwatch.
 215   """
 216
 217   def __init__(me, info, queue, tag, args, env):
 218     """
 219     Start a new child process.
 220
 221     The ARGS are a list of arguments to be given to the child process.  The
 222     ENV is either None or a dictionary of environment variable assignments to
 223     override the extant environment.  INFO is a list of tokens to be included
 224     in warnings about the child's stderr output.  If the child writes a line
 225     to standard output, put (TAG, 'stdout', LINE) to the QUEUE.  When the
 226     child exits, write (TAG, 'exit', CODE) to the QUEUE.
 227     """
 228     me._info = info
 229     me._q = queue
 230     me._tag = tag
 231     myenv = OS.environ.copy()
 232     if env: myenv.update(env)
 233     me._proc = PROC.Popen(args = args, env = myenv, bufsize = 1,
 234                           stdout = PROC.PIPE, stderr = PROC.PIPE)
 235     me._lq = SelLineQueue(me._proc.stdout, queue, tag, 'stdout')
 236     errorwatch.watch(me._proc.stderr, info)
 237     childwatch.watch(me._proc.pid, queue, tag)
 238
 239   def __del__(me):
 240     """
 241     If I've been forgotten then stop watching for termination.
 242     """
 243     childwatch.unwatch(me._proc.pid)
 244
 245 def potwatch(what, name, q):
 246   """
 247   Watch the queue Q for activity as reported by a Command object.
 248
 249   Information from the process's stdout is reported as
 250
 251     NOTE WHAT NAME stdout LINE
 252
 253   abnormal termination is reported as
 254
 255     WARN WHAT NAME CODE
 256
 257   where CODE is what the ChildWatch wrote.
 258   """
 259   eofp = deadp = False
 260   while not deadp or not eofp:
 261     _, kind, more = q.get()
 262     if kind == 'stdout':
 263       if more is None:
 264         eofp = True
 265       else:
 266         S.notify('connect', what, name, 'stdout', more)
 267     elif kind == 'exit':
 268       if more: S.warn('connect', what, name, *more)
 269       deadp = True
 270
 271 ###--------------------------------------------------------------------------
 272 ### Peer database utilities.
 273
 274 _magic = ['_magic']                     # An object distinct from all others
 275
 276 class Peer (object):
 277   """Representation of a peer in the database."""
 278
 279   def __init__(me, peer, cdb = None):
 280     """
 281     Create a new peer, named PEER.
 282
 283     Information about the peer is read from the database CDB, or the default
 284     one given on the command-line.
 285     """
 286     me.name = peer
 287     record = (cdb or CDB.init(opts.cdb))['P' + peer]
 288     me.__dict__.update(M.URLDecode(record, semip = True))
 289
 290   def get(me, key, default = _magic, filter = None):
 291     """
 292     Get the information stashed under KEY from the peer's database record.
 293
 294     If DEFAULT is given, then use it if the database doesn't contain the
 295     necessary information.  If no DEFAULT is given, then report an error.  If
 296     a FILTER function is given then apply it to the information from the
 297     database before returning it.
 298     """
 299     try:
 300       attr = me.__dict__[key]
 301     except KeyError:
 302       if default is _magic:
 303         raise T.TripeJobError('malformed-peer', me.name, 'missing-key', key)
 304       return default
 305     else:
 306       if filter is not None: attr = filter(attr)
 307       return attr
 308
 309   def has(me, key):
 310     """
 311     Return whether the peer's database record has the KEY.
 312     """
 313     return key in me.__dict__
 314
 315   def list(me):
 316     """
 317     Iterate over the available keys in the peer's database record.
 318     """
 319     return me.__dict__.iterkeys()
 320
 321 def boolean(value):
 322   """Parse VALUE as a boolean."""
 323   return value in ['t', 'true', 'y', 'yes', 'on']
 324
 325 ###--------------------------------------------------------------------------
 326 ### Waking up and watching peers.
 327
 328 def run_connect(peer, cmd):
 329   """
 330   Start the job of connecting to the passive PEER.
 331
 332   The CMD string is a shell command which will connect to the peer (via some
 333   back-channel, say ssh and userv), issue a command
 334
 335     SVCSUBMIT connect passive [OPTIONS] USER
 336
 337   and write the resulting challenge to standard error.
 338   """
 339   q = T.Queue()
 340   cmd = Command(['connect', peer.name], q, 'connect',
 341                 ['/bin/sh', '-c', cmd], None)
 342   _, kind, more = q.peek()
 343   if kind == 'stdout':
 344     if more is None:
 345       S.warn('connect', 'connect', peer.name, 'unexpected-eof')
 346     else:
 347       chal = more
 348       S.greet(peer.name, chal)
 349       q.get()
 350   potwatch('connect', peer.name, q)
 351
 352 def run_disconnect(peer, cmd):
 353   """
 354   Start the job of disconnecting from a passive PEER.
 355
 356   The CMD string is a shell command which will disconnect from the peer.
 357   """
 358   q = T.Queue()
 359   cmd = Command(['disconnect', peer.name], q, 'disconnect',
 360                 ['/bin/sh', '-c', cmd], None)
 361   potwatch('disconnect', peer.name, q)
 362
 363 _pingseq = 0
 364 class PingPeer (object):
 365   """
 366   Object representing a peer which we are pinging to ensure that it is still
 367   present.
 368
 369   PingPeer objects are held by the Pinger (q.v.).  The Pinger maintains an
 370   event queue -- which saves us from having an enormous swarm of coroutines
 371   -- but most of the actual work is done here.
 372
 373   In order to avoid confusion between different PingPeer instances for the
 374   same actual peer, each PingPeer has a sequence number (its `seq'
 375   attribute).  Events for the PingPeer are identified by a (PEER, SEQ) pair.
 376   (Using the PingPeer instance itself will prevent garbage collection of
 377   otherwise defunct instances.)
 378   """
 379
 380   def __init__(me, pinger, queue, peer, pingnow):
 381     """
 382     Create a new PingPeer.
 383
 384     The PINGER is the Pinger object we should send the results to.  This is
 385     used when we remove ourselves, if the peer has been explicitly removed.
 386
 387     The QUEUE is the event queue on which timer and ping-command events
 388     should be written.
 389
 390     The PEER is a `Peer' object describing the peer.
 391
 392     If PINGNOW is true, then immediately start pinging the peer.  Otherwise
 393     wait until the usual retry interval.
 394     """
 395     global _pingseq
 396     me._pinger = pinger
 397     me._q = queue
 398     me._peer = peer.name
 399     me.update(peer)
 400     me.seq = _pingseq
 401     _pingseq += 1
 402     me._failures = 0
 403     me._sabotage = False
 404     me._last = '-'
 405     me._nping = 0
 406     me._nlost = 0
 407     me._sigma_t = 0
 408     me._sigma_t2 = 0
 409     me._min = me._max = '-'
 410     now = time()
 411     if pingnow:
 412       me._timer = None
 413       me._ping()
 414     else:
 415       me._timer = M.SelTimer(now + me._every, me._time)
 416     me._last_reconn = now
 417
 418   def update(me, peer):
 419     """
 420     Refreshes the timer parameters for this peer.  We don't, however,
 421     immediately reschedule anything: that will happen next time anything
 422     interesting happens.
 423     """
 424     if peer is None: peer = Peer(me._peer)
 425     assert peer.name == me._peer
 426     me._every = peer.get('every', filter = T.timespec, default = 120)
 427     me._timeout = peer.get('timeout', filter = T.timespec, default = 10)
 428     me._retries = peer.get('retries', filter = int, default = 5)
 429     me._connectp = peer.has('connect')
 430     me._knockp = peer.has('knock')
 431     return me
 432
 433   def _ping(me):
 434     """
 435     Send a ping to the peer; the result is sent to the Pinger's event queue.
 436     """
 437     S.rawcommand(T.TripeAsynchronousCommand(
 438       me._q, (me._peer, me.seq),
 439       ['EPING',
 440        '-background', S.bgtag(),
 441        '-timeout', str(me._timeout),
 442        '--',
 443        me._peer]))
 444
 445   def _reconnect(me, now):
 446     now = time()
 447     try:
 448       peer = Peer(me._peer)
 449       if me._connectp or me._knockp:
 450         S.warn('connect', 'reconnecting', me._peer)
 451         S.forcekx(me._peer, quiet = not me._knockp)
 452         if me._connectp: T.spawn(run_connect, peer, peer.get('connect'))
 453         me._timer = M.SelTimer(now + me._every, me._time)
 454         me._sabotage = False
 455         me._last_reconn = now
 456       else:
 457         S.kill(me._peer)
 458     except T.TripeError, e:
 459       if e.args[0] == 'unknown-peer': me._pinger.kill(me._peer)
 460
 461   def reconnect(me):
 462     """
 463     Attempt reconnection to the peer.
 464
 465     Applies rate-limiting so that we don't hammer a remote peer just because
 466     we notice several problems in a short time interval.
 467     """
 468     now = time()
 469     if now >= me._last_reconn + 5: me._reconnect(now)
 470
 471   def event(me, code, stuff):
 472     """
 473     Respond to an event which happened to this peer.
 474
 475     Timer events indicate that we should start a new ping.  (The server has
 476     its own timeout which detects lost packets.)
 477
 478     We trap unknown-peer responses and detach from the Pinger.
 479
 480     If the ping fails and we run out of retries, we attempt to restart the
 481     connection.
 482     """
 483     now = time()
 484     if code == 'TIMER':
 485       me._failures = 0
 486       me._ping()
 487     elif code == 'FAIL':
 488       S.notify('connect', 'ping-failed', me._peer, *stuff)
 489       if not stuff: pass
 490       elif stuff[0] == 'unknown-peer': me._pinger.kill(me._peer)
 491       elif stuff[0] == 'ping-send-failed': me._reconnect(now)
 492     elif code == 'INFO':
 493       outcome = stuff[0]
 494       if outcome == 'ping-ok' and me._sabotage:
 495         outcome = 'ping-timeout'
 496       if outcome == 'ping-ok':
 497         if me._failures > 0: S.warn('connect', 'ping-ok', me._peer)
 498         t = float(stuff[1])
 499         me._last = '%.1fms' % t
 500         me._sigma_t += t
 501         me._sigma_t2 += t*t
 502         me._nping += 1
 503         if me._min == '-' or t < me._min: me._min = t
 504         if me._max == '-' or t > me._max: me._max = t
 505         me._timer = M.SelTimer(now + me._every, me._time)
 506       elif outcome == 'ping-timeout':
 507         me._failures += 1
 508         me._nlost += 1
 509         S.warn('connect', 'ping-timeout', me._peer,
 510                'attempt', str(me._failures), 'of', str(me._retries))
 511         if me._failures < me._retries:
 512           me._ping()
 513           me._last = 'timeout'
 514         else:
 515           me._reconnect(now)
 516           me._last = 'reconnect'
 517       elif outcome == 'ping-peer-died':
 518         me._pinger.kill(me._peer)
 519
 520   def sabotage(me):
 521     """Sabotage the peer, for testing purposes."""
 522     me._sabotage = True
 523     if me._timer: me._timer.kill()
 524     T.defer(me._time)
 525
 526   def info(me):
 527     if not me._nping:
 528       mean = sd = min = max = '-'
 529     else:
 530       meanval = me._sigma_t/me._nping
 531       mean = '%.1fms' % meanval
 532       sd = '%.1fms' % sqrt(me._sigma_t2/me._nping - meanval*meanval)
 533       min = '%.1fms' % me._min
 534       max = '%.1fms' % me._max
 535     n = me._nping + me._nlost
 536     if not n: pclost = '-'
 537     else: pclost = '%d' % ((100*me._nlost + n//2)//n)
 538     return { 'last-ping': me._last,
 539              'mean-ping': mean,
 540              'sd-ping': sd,
 541              'n-ping': '%d' % me._nping,
 542              'n-lost': '%d' % me._nlost,
 543              'percent-lost': pclost,
 544              'min-ping': min,
 545              'max-ping': max,
 546              'state': me._timer and 'idle' or 'check',
 547              'failures': str(me._failures) }
 548
 549   @T._callback
 550   def _time(me):
 551     """
 552     Handle timer callbacks by posting a timeout event on the queue.
 553     """
 554     me._timer = None
 555     me._q.put(((me._peer, me.seq), 'TIMER', None))
 556
 557   def __str__(me):
 558     return 'PingPeer(%s, %d, f = %d)' % (me._peer, me.seq, me._failures)
 559   def __repr__(me):
 560     return str(me)
 561
 562 class Pinger (T.Coroutine):
 563   """
 564   The Pinger keeps track of the peers which we expect to be connected and
 565   takes action if they seem to stop responding.
 566
 567   There is usually only one Pinger, called pinger.
 568
 569   The Pinger maintains a collection of PingPeer objects, and an event queue.
 570   The PingPeers direct the results of their pings, and timer events, to the
 571   event queue.  The Pinger's coroutine picks items off the queue and
 572   dispatches them back to the PingPeers as appropriate.
 573   """
 574
 575   def __init__(me):
 576     """Initialize the Pinger."""
 577     T.Coroutine.__init__(me)
 578     me._peers = {}
 579     me._q = T.Queue()
 580
 581   def run(me):
 582     """
 583     Coroutine function: reads the pinger queue and sends events to the
 584     PingPeer objects they correspond to.
 585     """
 586     while True:
 587       (peer, seq), code, stuff = me._q.get()
 588       if peer in me._peers and seq == me._peers[peer].seq:
 589         try: me._peers[peer].event(code, stuff)
 590         except Exception, e:
 591           SYS.excepthook(*SYS.exc_info())
 592
 593   def add(me, peer, pingnow):
 594     """
 595     Add PEER to the collection of peers under the Pinger's watchful eye.
 596     The arguments are as for PingPeer: see above.
 597     """
 598     me._peers[peer.name] = PingPeer(me, me._q, peer, pingnow)
 599     return me
 600
 601   def kill(me, peername):
 602     """Remove PEER from the peers being watched by the Pinger."""
 603     try: del me._peers[peername]
 604     except KeyError: pass
 605     return me
 606
 607   def rescan(me, startup):
 608     """
 609     General resynchronization method.
 610
 611     We scan the list of peers (with connect scripts) known at the server.
 612     Any which are known to the Pinger but aren't known to the server are
 613     removed from our list; newly arrived peers are added.  (Note that a peer
 614     can change state here either due to the server sneakily changing its list
 615     without issuing notifications or, more likely, the database changing its
 616     idea of whether a peer is interesting.)  Finally, PingPeers which are
 617     still present are prodded to update their timing parameters.
 618
 619     This method is called once at startup to pick up the peers already
 620     installed, and again by the dbwatcher coroutine when it detects a change
 621     to the database.
 622     """
 623     if T._debug: print '# rescan peers'
 624     correct = {}
 625     start = {}
 626     for name in S.list():
 627       try: peer = Peer(name)
 628       except KeyError: continue
 629       if peer.get('watch', filter = boolean, default = False):
 630         if T._debug: print '# interesting peer %s' % peer
 631         correct[peer.name] = start[peer.name] = peer
 632       elif startup:
 633         if T._debug: print '# peer %s ready for adoption' % peer
 634         start[peer.name] = peer
 635     for name, obj in me._peers.items():
 636       try:
 637         peer = correct[name]
 638       except KeyError:
 639         if T._debug: print '# peer %s vanished' % name
 640         del me._peers[name]
 641       else:
 642         obj.update(peer)
 643     for name, peer in start.iteritems():
 644       if name in me._peers: continue
 645       if startup:
 646         if T._debug: print '# setting up peer %s' % name
 647         ifname = S.ifname(name)
 648         addr = S.addr(name)
 649         T.defer(adoptpeer, peer, ifname, *addr)
 650       else:
 651         if T._debug: print '# adopting new peer %s' % name
 652         me.add(peer, True)
 653     return me
 654
 655   def adopted(me):
 656     """
 657     Returns the list of peers being watched by the Pinger.
 658     """
 659     return me._peers.keys()
 660
 661   def find(me, name):
 662     """Return the PingPeer with the given name."""
 663     return me._peers[name]
 664
 665 ###--------------------------------------------------------------------------
 666 ### New connections.
 667
 668 def encode_envvars(env, prefix, vars):
 669   """
 670   Encode the variables in VARS suitably for including in a program
 671   environment.  Lowercase letters in variable names are forced to uppercase;
 672   runs of non-alphanumeric characters are replaced by single underscores; and
 673   the PREFIX is prepended.  The resulting variables are written to ENV.
 674   """
 675   for k, v in vars.iteritems():
 676     env[prefix + r_bad.sub('_', k.upper())] = v
 677
 678 r_bad = RX.compile(r'[\W_]+')
 679 def envvars(peer):
 680   """
 681   Translate the database information for a PEER into a dictionary of
 682   environment variables with plausible upper-case names and a P_ prefix.
 683   Also collect the crypto information into A_ variables.
 684   """
 685   env = {}
 686   encode_envvars(env, 'P_', dict([(k, peer.get(k)) for k in peer.list()]))
 687   encode_envvars(env, 'A_', S.algs(peer.name))
 688   return env
 689
 690 def run_ifupdown(what, peer, *args):
 691   """
 692   Run the interface up/down script for a peer.
 693
 694   WHAT is 'ifup' or 'ifdown'.  PEER names the peer in question.  ARGS is a
 695   list of arguments to pass to the script, in addition to the peer name.
 696
 697   The command is run and watched in the background by potwatch.
 698   """
 699   q = T.Queue()
 700   c = Command([what, peer.name], q, what,
 701               M.split(peer.get(what), quotep = True)[0] +
 702               [peer.name] + list(args),
 703               envvars(peer))
 704   potwatch(what, peer.name, q)
 705
 706 def adoptpeer(peer, ifname, *addr):
 707   """
 708   Add a new peer to our collection.
 709
 710   PEER is the `Peer' object; IFNAME is the interface name for its tunnel; and
 711   ADDR is the list of tokens representing its address.
 712
 713   We try to bring up the interface and provoke a connection to the peer if
 714   it's passive.
 715   """
 716   if peer.has('ifup'):
 717     T.Coroutine(run_ifupdown, name = 'ifup %s' % peer.name) \
 718         .switch('ifup', peer, ifname, *addr)
 719   cmd = peer.get('connect', default = None)
 720   if cmd is not None:
 721     T.Coroutine(run_connect, name = 'connect %s' % peer.name) \
 722         .switch(peer, cmd)
 723   if peer.get('watch', filter = boolean, default = False):
 724     pinger.add(peer, False)
 725
 726 def disownpeer(peer):
 727   """Drop the PEER from the Pinger and put its interface to bed."""
 728   try: pinger.kill(peer)
 729   except KeyError: pass
 730   cmd = peer.get('disconnect', default = None)
 731   if cmd is not None:
 732     T.Coroutine(run_disconnect, name = 'disconnect %s' % peer.name) \
 733         .switch(peer, cmd)
 734   if peer.has('ifdown'):
 735     T.Coroutine(run_ifupdown, name = 'ifdown %s' % peer.name) \
 736         .switch('ifdown', peer)
 737
 738 def addpeer(peer, addr, ephemp):
 739   """
 740   Process a connect request from a new peer PEER on address ADDR.
 741
 742   Any existing peer with this name is disconnected from the server.  EPHEMP
 743   is the default ephemeral-ness state for the new peer.
 744   """
 745   if peer.name in S.list():
 746     S.kill(peer.name)
 747   try:
 748     S.add(peer.name,
 749           tunnel = peer.get('tunnel', default = None),
 750           keepalive = peer.get('keepalive', default = None),
 751           key = peer.get('key', default = None),
 752           priv = peer.get('priv', default = None),
 753           mobile = peer.get('mobile', filter = boolean, default = False),
 754           knock = peer.get('knock', default = None),
 755           cork = peer.get('cork', filter = boolean, default = False),
 756           ephemeral = peer.get('ephemeral', filter = boolean,
 757                                default = ephemp),
 758           *addr)
 759   except T.TripeError, exc:
 760     raise T.TripeJobError(*exc.args)
 761
 762 ## Dictionary mapping challenges to waiting passive-connection coroutines.
 763 chalmap = {}
 764
 765 def notify(_, code, *rest):
 766   """
 767   Watch for notifications.
 768
 769   We trap ADD and KILL notifications, and send them straight to adoptpeer and
 770   disownpeer respectively; and dispatch GREET notifications to the
 771   corresponding waiting coroutine.
 772   """
 773   if code == 'ADD':
 774     try: p = Peer(rest[0])
 775     except KeyError: pass
 776     else: adoptpeer(p, *rest[1:])
 777   elif code == 'KILL':
 778     try: p = Peer(rest[0])
 779     except KeyError: pass
 780     else: disownpeer(p, *rest[1:])
 781   elif code == 'GREET':
 782     chal = rest[0]
 783     try: cr = chalmap[chal]
 784     except KeyError: pass
 785     else: cr.switch(rest[1:])
 786   elif code == 'KNOCK':
 787     try: p = Peer(rest[0])
 788     except KeyError:
 789       S.warn(['connect', 'knock-unknown-peer', rest[0]])
 790       return
 791     if p.get('peer') != 'PASSIVE':
 792       S.warn(['connect', 'knock-active-peer', p.name])
 793       return
 794     dot = p.name.find('.')
 795     if dot >= 0: kname = p.name[dot + 1:]
 796     else: kname = p.name
 797     ktag = p.get('key', p.name)
 798     if kname != ktag:
 799       S.warn(['connect', 'knock-tag-mismatch',
 800               'peer', pname, 'public-key-tag', ktag])
 801       return
 802     T.spawn(addpeer, p, rest[1:], True)
 803
 804 ###--------------------------------------------------------------------------
 805 ### Command implementation.
 806
 807 def cmd_kick(name):
 808   """
 809   kick NAME: Force a new connection attempt for the NAMEd peer.
 810   """
 811   try: pp = pinger.find(name)
 812   except KeyError: raise T.TripeJobError('peer-not-adopted', name)
 813   try: peer = Peer(name)
 814   except KeyError: raise T.TripeJobError('unknown-peer', name)
 815   conn = peer.get('connect', None)
 816   if conn: T.spawn(run_connect, peer, peer.get('connect'))
 817   else: T.spawn(lambda p: S.forcekx(p.name), peer)
 818
 819 def cmd_adopted():
 820   """
 821   adopted: Report a list of adopted peers.
 822   """
 823   for name in pinger.adopted():
 824     T.svcinfo(name)
 825
 826 def cmd_active(name):
 827   """
 828   active NAME: Handle an active connection request for the peer called NAME.
 829
 830   The appropriate address is read from the database automatically.
 831   """
 832   try: peer = Peer(name)
 833   except KeyError: raise T.TripeJobError('unknown-peer', name)
 834   addr = peer.get('peer')
 835   if addr == 'PASSIVE':
 836     raise T.TripeJobError('passive-peer', name)
 837   addpeer(peer, M.split(addr, quotep = True)[0], True)
 838
 839 def cmd_listactive():
 840   """
 841   list: Report a list of the available active peers.
 842   """
 843   cdb = CDB.init(opts.cdb)
 844   for key in cdb.keys():
 845     if key.startswith('P') and Peer(key[1:]).get('peer', '') != 'PASSIVE':
 846       T.svcinfo(key[1:])
 847
 848 def cmd_info(name):
 849   """
 850   info NAME: Report the database entries for the named peer.
 851   """
 852   try: peer = Peer(name)
 853   except KeyError: raise T.TripeJobError('unknown-peer', name)
 854   d = {}
 855   try: pp = pinger.find(name)
 856   except KeyError: pass
 857   else: d.update(pp.info())
 858   items = list(peer.list()) + d.keys()
 859   items.sort()
 860   for i in items:
 861     try: v = d[i]
 862     except KeyError: v = peer.get(i)
 863     T.svcinfo('%s=%s' % (i, v.replace('\n', ' ')))
 864
 865 def cmd_userpeer(user):
 866   """
 867   userpeer USER: Report the peer name for the named user.
 868   """
 869   try: name = CDB.init(opts.cdb)['U' + user]
 870   except KeyError: raise T.TripeJobError('unknown-user', user)
 871   T.svcinfo(name)
 872
 873 def cmd_passive(*args):
 874   """
 875   passive [OPTIONS] USER: Await the arrival of the named USER.
 876
 877   Report a challenge; when (and if!) the server receives a greeting quoting
 878   this challenge, add the corresponding peer to the server.
 879   """
 880   now = time()
 881   timeout = 30
 882   op = T.OptParse(args, ['-timeout'])
 883   for opt in op:
 884     if opt == '-timeout':
 885       timeout = T.timespec(op.arg())
 886   user, = op.rest(1, 1)
 887   try: name = CDB.init(opts.cdb)['U' + user]
 888   except KeyError: raise T.TripeJobError('unknown-user', user)
 889   try: peer = Peer(name)
 890   except KeyError: raise T.TripeJobError('unknown-peer', name)
 891   chal = S.getchal()
 892   cr = T.Coroutine.getcurrent()
 893   timer = M.SelTimer(now + timeout, lambda: cr.switch(None))
 894   try:
 895     T.svcinfo(chal)
 896     chalmap[chal] = cr
 897     addr = cr.parent.switch()
 898     if addr is None:
 899       raise T.TripeJobError('connect-timeout')
 900     addpeer(peer, addr, True)
 901   finally:
 902     del chalmap[chal]
 903
 904 def cmd_sabotage(name):
 905   """
 906   sabotage NAME: Sabotage the NAMEd peer so that we think it can't be pinged.
 907   """
 908   try: pp = pinger.find(name)
 909   except KeyError: raise T.TripeJobError('unknown-peer', name)
 910   pp.sabotage()
 911
 912 ###--------------------------------------------------------------------------
 913 ### Start up.
 914
 915 def setup():
 916   """
 917   Service setup.
 918
 919   Register the notification watcher, rescan the peers, and add automatic
 920   active peers.
 921   """
 922   S.handler['NOTE'] = notify
 923   S.watch('+n')
 924
 925   pinger.rescan(opts.startup)
 926
 927   if opts.startup:
 928     cdb = CDB.init(opts.cdb)
 929     try:
 930       autos = cdb['%AUTO']
 931     except KeyError:
 932       autos = ''
 933     for name in M.split(autos)[0]:
 934       try:
 935         peer = Peer(name, cdb)
 936         addpeer(peer, M.split(peer.get('peer'), quotep = True)[0], False)
 937       except T.TripeJobError, err:
 938         S.warn('connect', 'auto-add-failed', name, *err.args)
 939
 940 def init():
 941   """
 942   Initialization to be done before service startup.
 943   """
 944   global errorwatch, childwatch, pinger
 945   errorwatch = ErrorWatch()
 946   childwatch = ChildWatch()
 947   pinger = Pinger()
 948   T.Coroutine(dbwatch, name = 'dbwatch').switch()
 949   errorwatch.switch()
 950   pinger.switch()
 951
 952 def parse_options():
 953   """
 954   Parse the command-line options.
 955
 956   Automatically changes directory to the requested configdir, and turns on
 957   debugging.  Returns the options object.
 958   """
 959   op = OptionParser(usage = '%prog [-a FILE] [-d DIR]',
 960                     version = '%%prog %s' % VERSION)
 961
 962   op.add_option('-a', '--admin-socket',
 963                 metavar = 'FILE', dest = 'tripesock', default = T.tripesock,
 964                 help = 'Select socket to connect to [default %default]')
 965   op.add_option('-d', '--directory',
 966                 metavar = 'DIR', dest = 'dir', default = T.configdir,
 967                 help = 'Select current diretory [default %default]')
 968   op.add_option('-p', '--peerdb',
 969                 metavar = 'FILE', dest = 'cdb', default = T.peerdb,
 970                 help = 'Select peers database [default %default]')
 971   op.add_option('--daemon', dest = 'daemon',
 972                 default = False, action = 'store_true',
 973                 help = 'Become a daemon after successful initialization')
 974   op.add_option('--debug', dest = 'debug',
 975                 default = False, action = 'store_true',
 976                 help = 'Emit debugging trace information')
 977   op.add_option('--startup', dest = 'startup',
 978                 default = False, action = 'store_true',
 979                 help = 'Being called as part of the server startup')
 980
 981   opts, args = op.parse_args()
 982   if args: op.error('no arguments permitted')
 983   OS.chdir(opts.dir)
 984   T._debug = opts.debug
 985   return opts
 986
 987 ## Service table, for running manually.
 988 service_info = [('connect', VERSION, {
 989   'adopted': (0, 0, '', cmd_adopted),
 990   'kick': (1, 1, 'PEER', cmd_kick),
 991   'passive': (1, None, '[OPTIONS] USER', cmd_passive),
 992   'active': (1, 1, 'PEER', cmd_active),
 993   'info': (1, 1, 'PEER', cmd_info),
 994   'list-active': (0, 0, '', cmd_listactive),
 995   'userpeer': (1, 1, 'USER', cmd_userpeer),
 996   'sabotage': (1, 1, 'PEER', cmd_sabotage)
 997 })]
 998
 999 if __name__ == '__main__':
1000   opts = parse_options()
1001   OS.environ['TRIPESOCK'] = opts.tripesock
1002   T.runservices(opts.tripesock, service_info,
1003                 init = init, setup = setup,
1004                 daemon = opts.daemon)
1005
1006 ###----- That's all, folks --------------------------------------------------