1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
Demo/rpc/rpc.py
# Sun RPC version 2 -- RFC1057.

# XXX There should be separate exceptions for the various reasons why
# XXX an RPC can fail, rather than using RuntimeError for everything

# XXX Need to use class based exceptions rather than string exceptions

# XXX The UDP version of the protocol resends requests when it does
# XXX not receive a timely reply -- use only for idempotent calls!

# XXX There is no provision for call timeout on TCP connections

import xdr
import socket
import os

RPCVERSION = 2

CALL = 0
REPLY = 1

AUTH_NULL = 0
AUTH_UNIX = 1
AUTH_SHORT = 2
AUTH_DES = 3

MSG_ACCEPTED = 0
MSG_DENIED = 1

SUCCESS = 0                             # RPC executed successfully
PROG_UNAVAIL  = 1                       # remote hasn't exported program
PROG_MISMATCH = 2                       # remote can't support version #
PROC_UNAVAIL  = 3                       # program can't support procedure
GARBAGE_ARGS  = 4                       # procedure can't decode params

RPC_MISMATCH = 0                        # RPC version number != 2
AUTH_ERROR = 1                          # remote can't authenticate caller

AUTH_BADCRED      = 1                   # bad credentials (seal broken)
AUTH_REJECTEDCRED = 2                   # client must begin new session
AUTH_BADVERF      = 3                   # bad verifier (seal broken)
AUTH_REJECTEDVERF = 4                   # verifier expired or replayed
AUTH_TOOWEAK      = 5                   # rejected for security reasons


class Packer(xdr.Packer):

    def pack_auth(self, auth):
        flavor, stuff = auth
        self.pack_enum(flavor)
        self.pack_opaque(stuff)

    def pack_auth_unix(self, stamp, machinename, uid, gid, gids):
        self.pack_uint(stamp)
        self.pack_string(machinename)
        self.pack_uint(uid)
        self.pack_uint(gid)
        self.pack_uint(len(gids))
        for i in gids:
            self.pack_uint(i)

    def pack_callheader(self, xid, prog, vers, proc, cred, verf):
        self.pack_uint(xid)
        self.pack_enum(CALL)
        self.pack_uint(RPCVERSION)
        self.pack_uint(prog)
        self.pack_uint(vers)
        self.pack_uint(proc)
        self.pack_auth(cred)
        self.pack_auth(verf)
        # Caller must add procedure-specific part of call

    def pack_replyheader(self, xid, verf):
        self.pack_uint(xid)
        self.pack_enum(REPLY)
        self.pack_uint(MSG_ACCEPTED)
        self.pack_auth(verf)
        self.pack_enum(SUCCESS)
        # Caller must add procedure-specific part of reply


# Exceptions
class BadRPCFormat(Exception): pass
class BadRPCVersion(Exception): pass
class GarbageArgs(Exception): pass

class Unpacker(xdr.Unpacker):

    def unpack_auth(self):
        flavor = self.unpack_enum()
        stuff = self.unpack_opaque()
        return (flavor, stuff)

    def unpack_callheader(self):
        xid = self.unpack_uint()
        temp = self.unpack_enum()
        if temp != CALL:
            raise BadRPCFormat, 'no CALL but %r' % (temp,)
        temp = self.unpack_uint()
        if temp != RPCVERSION:
            raise BadRPCVersion, 'bad RPC version %r' % (temp,)
        prog = self.unpack_uint()
        vers = self.unpack_uint()
        proc = self.unpack_uint()
        cred = self.unpack_auth()
        verf = self.unpack_auth()
        return xid, prog, vers, proc, cred, verf
        # Caller must add procedure-specific part of call

    def unpack_replyheader(self):
        xid = self.unpack_uint()
        mtype = self.unpack_enum()
        if mtype != REPLY:
            raise RuntimeError, 'no REPLY but %r' % (mtype,)
        stat = self.unpack_enum()
        if stat == MSG_DENIED:
            stat = self.unpack_enum()
            if stat == RPC_MISMATCH:
                low = self.unpack_uint()
                high = self.unpack_uint()
                raise RuntimeError, \
                  'MSG_DENIED: RPC_MISMATCH: %r' % ((low, high),)
            if stat == AUTH_ERROR:
                stat = self.unpack_uint()
                raise RuntimeError, \
                        'MSG_DENIED: AUTH_ERROR: %r' % (stat,)
            raise RuntimeError, 'MSG_DENIED: %r' % (stat,)
        if stat != MSG_ACCEPTED:
            raise RuntimeError, \
              'Neither MSG_DENIED nor MSG_ACCEPTED: %r' % (stat,)
        verf = self.unpack_auth()
        stat = self.unpack_enum()
        if stat == PROG_UNAVAIL:
            raise RuntimeError, 'call failed: PROG_UNAVAIL'
        if stat == PROG_MISMATCH:
            low = self.unpack_uint()
            high = self.unpack_uint()
            raise RuntimeError, \
                    'call failed: PROG_MISMATCH: %r' % ((low, high),)
        if stat == PROC_UNAVAIL:
            raise RuntimeError, 'call failed: PROC_UNAVAIL'
        if stat == GARBAGE_ARGS:
            raise RuntimeError, 'call failed: GARBAGE_ARGS'
        if stat != SUCCESS:
            raise RuntimeError, 'call failed: %r' % (stat,)
        return xid, verf
        # Caller must get procedure-specific part of reply


# Subroutines to create opaque authentication objects

def make_auth_null():
    return ''

def make_auth_unix(seed, host, uid, gid, groups):
    p = Packer()
    p.pack_auth_unix(seed, host, uid, gid, groups)
    return p.get_buf()

def make_auth_unix_default():
    try:
        from os import getuid, getgid
        uid = getuid()
        gid = getgid()
    except ImportError:
        uid = gid = 0
    import time
    return make_auth_unix(int(time.time()-unix_epoch()), \
              socket.gethostname(), uid, gid, [])

_unix_epoch = -1
def unix_epoch():
    """Very painful calculation of when the Unix Epoch is.

    This is defined as the return value of time.time() on Jan 1st,
    1970, 00:00:00 GMT.

    On a Unix system, this should always return 0.0.  On a Mac, the
    calculations are needed -- and hard because of integer overflow
    and other limitations.

    """
    global _unix_epoch
    if _unix_epoch >= 0: return _unix_epoch
    import time
    now = time.time()
    localt = time.localtime(now)        # (y, m, d, hh, mm, ss, ..., ..., ...)
    gmt = time.gmtime(now)
    offset = time.mktime(localt) - time.mktime(gmt)
    y, m, d, hh, mm, ss = 1970, 1, 1, 0, 0, 0
    offset, ss = divmod(ss + offset, 60)
    offset, mm = divmod(mm + offset, 60)
    offset, hh = divmod(hh + offset, 24)
    d = d + offset
    _unix_epoch = time.mktime((y, m, d, hh, mm, ss, 0, 0, 0))
    print "Unix epoch:", time.ctime(_unix_epoch)
    return _unix_epoch


# Common base class for clients

class Client:

    def __init__(self, host, prog, vers, port):
        self.host = host
        self.prog = prog
        self.vers = vers
        self.port = port
        self.makesocket() # Assigns to self.sock
        self.bindsocket()
        self.connsocket()
        self.lastxid = 0 # XXX should be more random?
        self.addpackers()
        self.cred = None
        self.verf = None

    def close(self):
        self.sock.close()

    def makesocket(self):
        # This MUST be overridden
        raise RuntimeError, 'makesocket not defined'

    def connsocket(self):
        # Override this if you don't want/need a connection
        self.sock.connect((self.host, self.port))

    def bindsocket(self):
        # Override this to bind to a different port (e.g. reserved)
        self.sock.bind(('', 0))

    def addpackers(self):
        # Override this to use derived classes from Packer/Unpacker
        self.packer = Packer()
        self.unpacker = Unpacker('')

    def make_call(self, proc, args, pack_func, unpack_func):
        # Don't normally override this (but see Broadcast)
        if pack_func is None and args is not None:
            raise TypeError, 'non-null args with null pack_func'
        self.start_call(proc)
        if pack_func:
            pack_func(args)
        self.do_call()
        if unpack_func:
            result = unpack_func()
        else:
            result = None
        self.unpacker.done()
        return result

    def start_call(self, proc):
        # Don't override this
        self.lastxid = xid = self.lastxid + 1
        cred = self.mkcred()
        verf = self.mkverf()
        p = self.packer
        p.reset()
        p.pack_callheader(xid, self.prog, self.vers, proc, cred, verf)

    def do_call(self):
        # This MUST be overridden
        raise RuntimeError, 'do_call not defined'

    def mkcred(self):
        # Override this to use more powerful credentials
        if self.cred is None:
            self.cred = (AUTH_NULL, make_auth_null())
        return self.cred

    def mkverf(self):
        # Override this to use a more powerful verifier
        if self.verf is None:
            self.verf = (AUTH_NULL, make_auth_null())
        return self.verf

    def call_0(self):               # Procedure 0 is always like this
        return self.make_call(0, None, None, None)


# Record-Marking standard support

def sendfrag(sock, last, frag):
    x = len(frag)
    if last: x = x | 0x80000000L
    header = (chr(int(x>>24 & 0xff)) + chr(int(x>>16 & 0xff)) + \
              chr(int(x>>8 & 0xff)) + chr(int(x & 0xff)))
    sock.send(header + frag)

def sendrecord(sock, record):
    sendfrag(sock, 1, record)

def recvfrag(sock):
    header = sock.recv(4)
    if len(header) < 4:
        raise EOFError
    x = long(ord(header[0]))<<24 | ord(header[1])<<16 | \
        ord(header[2])<<8 | ord(header[3])
    last = ((x & 0x80000000) != 0)
    n = int(x & 0x7fffffff)
    frag = ''
    while n > 0:
        buf = sock.recv(n)
        if not buf: raise EOFError
        n = n - len(buf)
        frag = frag + buf
    return last, frag

def recvrecord(sock):
    record = ''
    last = 0
    while not last:
        last, frag = recvfrag(sock)
        record = record + frag
    return record


# Try to bind to a reserved port (must be root)

last_resv_port_tried = None
def bindresvport(sock, host):
    global last_resv_port_tried
    FIRST, LAST = 600, 1024 # Range of ports to try
    if last_resv_port_tried is None:
        import os
        last_resv_port_tried = FIRST + os.getpid() % (LAST-FIRST)
    for i in range(last_resv_port_tried, LAST) + \
              range(FIRST, last_resv_port_tried):
        last_resv_port_tried = i
        try:
            sock.bind((host, i))
            return last_resv_port_tried
        except socket.error, (errno, msg):
            if errno != 114:
                raise socket.error, (errno, msg)
    raise RuntimeError, 'can\'t assign reserved port'


# Client using TCP to a specific port

class RawTCPClient(Client):

    def makesocket(self):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    def do_call(self):
        call = self.packer.get_buf()
        sendrecord(self.sock, call)
        reply = recvrecord(self.sock)
        u = self.unpacker
        u.reset(reply)
        xid, verf = u.unpack_replyheader()
        if xid != self.lastxid:
            # Can't really happen since this is TCP...
            raise RuntimeError, 'wrong xid in reply %r instead of %r' % (
                                 xid, self.lastxid)


# Client using UDP to a specific port

class RawUDPClient(Client):

    def makesocket(self):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

    def do_call(self):
        call = self.packer.get_buf()
        self.sock.send(call)
        try:
            from select import select
        except ImportError:
            print 'WARNING: select not found, RPC may hang'
            select = None
        BUFSIZE = 8192 # Max UDP buffer size
        timeout = 1
        count = 5
        while 1:
            r, w, x = [self.sock], [], []
            if select:
                r, w, x = select(r, w, x, timeout)
            if self.sock not in r:
                count = count - 1
                if count < 0: raise RuntimeError, 'timeout'
                if timeout < 25: timeout = timeout *2
##                              print 'RESEND', timeout, count
                self.sock.send(call)
                continue
            reply = self.sock.recv(BUFSIZE)
            u = self.unpacker
            u.reset(reply)
            xid, verf = u.unpack_replyheader()
            if xid != self.lastxid:
##                              print 'BAD xid'
                continue
            break


# Client using UDP broadcast to a specific port

class RawBroadcastUDPClient(RawUDPClient):

    def __init__(self, bcastaddr, prog, vers, port):
        RawUDPClient.__init__(self, bcastaddr, prog, vers, port)
        self.reply_handler = None
        self.timeout = 30

    def connsocket(self):
        # Don't connect -- use sendto
        self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

    def set_reply_handler(self, reply_handler):
        self.reply_handler = reply_handler

    def set_timeout(self, timeout):
        self.timeout = timeout # Use None for infinite timeout

    def make_call(self, proc, args, pack_func, unpack_func):
        if pack_func is None and args is not None:
            raise TypeError, 'non-null args with null pack_func'
        self.start_call(proc)
        if pack_func:
            pack_func(args)
        call = self.packer.get_buf()
        self.sock.sendto(call, (self.host, self.port))
        try:
            from select import select
        except ImportError:
            print 'WARNING: select not found, broadcast will hang'
            select = None
        BUFSIZE = 8192 # Max UDP buffer size (for reply)
        replies = []
        if unpack_func is None:
            def dummy(): pass
            unpack_func = dummy
        while 1:
            r, w, x = [self.sock], [], []
            if select:
                if self.timeout is None:
                    r, w, x = select(r, w, x)
                else:
                    r, w, x = select(r, w, x, self.timeout)
            if self.sock not in r:
                break
            reply, fromaddr = self.sock.recvfrom(BUFSIZE)
            u = self.unpacker
            u.reset(reply)
            xid, verf = u.unpack_replyheader()
            if xid != self.lastxid:
##                              print 'BAD xid'
                continue
            reply = unpack_func()
            self.unpacker.done()
            replies.append((reply, fromaddr))
            if self.reply_handler:
                self.reply_handler(reply, fromaddr)
        return replies


# Port mapper interface

# Program number, version and (fixed!) port number
PMAP_PROG = 100000
PMAP_VERS = 2
PMAP_PORT = 111

# Procedure numbers
PMAPPROC_NULL = 0                       # (void) -> void
PMAPPROC_SET = 1                        # (mapping) -> bool
PMAPPROC_UNSET = 2                      # (mapping) -> bool
PMAPPROC_GETPORT = 3                    # (mapping) -> unsigned int
PMAPPROC_DUMP = 4                       # (void) -> pmaplist
PMAPPROC_CALLIT = 5                     # (call_args) -> call_result

# A mapping is (prog, vers, prot, port) and prot is one of:

IPPROTO_TCP = 6
IPPROTO_UDP = 17

# A pmaplist is a variable-length list of mappings, as follows:
# either (1, mapping, pmaplist) or (0).

# A call_args is (prog, vers, proc, args) where args is opaque;
# a call_result is (port, res) where res is opaque.


class PortMapperPacker(Packer):

    def pack_mapping(self, mapping):
        prog, vers, prot, port = mapping
        self.pack_uint(prog)
        self.pack_uint(vers)
        self.pack_uint(prot)
        self.pack_uint(port)

    def pack_pmaplist(self, list):
        self.pack_list(list, self.pack_mapping)

    def pack_call_args(self, ca):
        prog, vers, proc, args = ca
        self.pack_uint(prog)
        self.pack_uint(vers)
        self.pack_uint(proc)
        self.pack_opaque(args)


class PortMapperUnpacker(Unpacker):

    def unpack_mapping(self):
        prog = self.unpack_uint()
        vers = self.unpack_uint()
        prot = self.unpack_uint()
        port = self.unpack_uint()
        return prog, vers, prot, port

    def unpack_pmaplist(self):
        return self.unpack_list(self.unpack_mapping)

    def unpack_call_result(self):
        port = self.unpack_uint()
        res = self.unpack_opaque()
        return port, res


class PartialPortMapperClient:

    def addpackers(self):
        self.packer = PortMapperPacker()
        self.unpacker = PortMapperUnpacker('')

    def Set(self, mapping):
        return self.make_call(PMAPPROC_SET, mapping, \
                self.packer.pack_mapping, \
                self.unpacker.unpack_uint)

    def Unset(self, mapping):
        return self.make_call(PMAPPROC_UNSET, mapping, \
                self.packer.pack_mapping, \
                self.unpacker.unpack_uint)

    def Getport(self, mapping):
        return self.make_call(PMAPPROC_GETPORT, mapping, \
                self.packer.pack_mapping, \
                self.unpacker.unpack_uint)

    def Dump(self):
        return self.make_call(PMAPPROC_DUMP, None, \
                None, \
                self.unpacker.unpack_pmaplist)

    def Callit(self, ca):
        return self.make_call(PMAPPROC_CALLIT, ca, \
                self.packer.pack_call_args, \
                self.unpacker.unpack_call_result)


class TCPPortMapperClient(PartialPortMapperClient, RawTCPClient):

    def __init__(self, host):
        RawTCPClient.__init__(self, \
                host, PMAP_PROG, PMAP_VERS, PMAP_PORT)


class UDPPortMapperClient(PartialPortMapperClient, RawUDPClient):

    def __init__(self, host):
        RawUDPClient.__init__(self, \
                host, PMAP_PROG, PMAP_VERS, PMAP_PORT)


class BroadcastUDPPortMapperClient(PartialPortMapperClient, \
                                   RawBroadcastUDPClient):

    def __init__(self, bcastaddr):
        RawBroadcastUDPClient.__init__(self, \
                bcastaddr, PMAP_PROG, PMAP_VERS, PMAP_PORT)


# Generic clients that find their server through the Port mapper

class TCPClient(RawTCPClient):

    def __init__(self, host, prog, vers):
        pmap = TCPPortMapperClient(host)
        port = pmap.Getport((prog, vers, IPPROTO_TCP, 0))
        pmap.close()
        if port == 0:
            raise RuntimeError, 'program not registered'
        RawTCPClient.__init__(self, host, prog, vers, port)


class UDPClient(RawUDPClient):

    def __init__(self, host, prog, vers):
        pmap = UDPPortMapperClient(host)
        port = pmap.Getport((prog, vers, IPPROTO_UDP, 0))
        pmap.close()
        if port == 0:
            raise RuntimeError, 'program not registered'
        RawUDPClient.__init__(self, host, prog, vers, port)


class BroadcastUDPClient(Client):

    def __init__(self, bcastaddr, prog, vers):
        self.pmap = BroadcastUDPPortMapperClient(bcastaddr)
        self.pmap.set_reply_handler(self.my_reply_handler)
        self.prog = prog
        self.vers = vers
        self.user_reply_handler = None
        self.addpackers()

    def close(self):
        self.pmap.close()

    def set_reply_handler(self, reply_handler):
        self.user_reply_handler = reply_handler

    def set_timeout(self, timeout):
        self.pmap.set_timeout(timeout)

    def my_reply_handler(self, reply, fromaddr):
        port, res = reply
        self.unpacker.reset(res)
        result = self.unpack_func()
        self.unpacker.done()
        self.replies.append((result, fromaddr))
        if self.user_reply_handler is not None:
            self.user_reply_handler(result, fromaddr)

    def make_call(self, proc, args, pack_func, unpack_func):
        self.packer.reset()
        if pack_func:
            pack_func(args)
        if unpack_func is None:
            def dummy(): pass
            self.unpack_func = dummy
        else:
            self.unpack_func = unpack_func
        self.replies = []
        packed_args = self.packer.get_buf()
        dummy_replies = self.pmap.Callit( \
                (self.prog, self.vers, proc, packed_args))
        return self.replies


# Server classes

# These are not symmetric to the Client classes
# XXX No attempt is made to provide authorization hooks yet

class Server:

    def __init__(self, host, prog, vers, port):
        self.host = host # Should normally be '' for default interface
        self.prog = prog
        self.vers = vers
        self.port = port # Should normally be 0 for random port
        self.makesocket() # Assigns to self.sock and self.prot
        self.bindsocket()
        self.host, self.port = self.sock.getsockname()
        self.addpackers()

    def register(self):
        mapping = self.prog, self.vers, self.prot, self.port
        p = TCPPortMapperClient(self.host)
        if not p.Set(mapping):
            raise RuntimeError, 'register failed'

    def unregister(self):
        mapping = self.prog, self.vers, self.prot, self.port
        p = TCPPortMapperClient(self.host)
        if not p.Unset(mapping):
            raise RuntimeError, 'unregister failed'

    def handle(self, call):
        # Don't use unpack_header but parse the header piecewise
        # XXX I have no idea if I am using the right error responses!
        self.unpacker.reset(call)
        self.packer.reset()
        xid = self.unpacker.unpack_uint()
        self.packer.pack_uint(xid)
        temp = self.unpacker.unpack_enum()
        if temp != CALL:
            return None # Not worthy of a reply
        self.packer.pack_uint(REPLY)
        temp = self.unpacker.unpack_uint()
        if temp != RPCVERSION:
            self.packer.pack_uint(MSG_DENIED)
            self.packer.pack_uint(RPC_MISMATCH)
            self.packer.pack_uint(RPCVERSION)
            self.packer.pack_uint(RPCVERSION)
            return self.packer.get_buf()
        self.packer.pack_uint(MSG_ACCEPTED)
        self.packer.pack_auth((AUTH_NULL, make_auth_null()))
        prog = self.unpacker.unpack_uint()
        if prog != self.prog:
            self.packer.pack_uint(PROG_UNAVAIL)
            return self.packer.get_buf()
        vers = self.unpacker.unpack_uint()
        if vers != self.vers:
            self.packer.pack_uint(PROG_MISMATCH)
            self.packer.pack_uint(self.vers)
            self.packer.pack_uint(self.vers)
            return self.packer.get_buf()
        proc = self.unpacker.unpack_uint()
        methname = 'handle_' + repr(proc)
        try:
            meth = getattr(self, methname)
        except AttributeError:
            self.packer.pack_uint(PROC_UNAVAIL)
            return self.packer.get_buf()
        cred = self.unpacker.unpack_auth()
        verf = self.unpacker.unpack_auth()
        try:
            meth() # Unpack args, call turn_around(), pack reply
        except (EOFError, GarbageArgs):
            # Too few or too many arguments
            self.packer.reset()
            self.packer.pack_uint(xid)
            self.packer.pack_uint(REPLY)
            self.packer.pack_uint(MSG_ACCEPTED)
            self.packer.pack_auth((AUTH_NULL, make_auth_null()))
            self.packer.pack_uint(GARBAGE_ARGS)
        return self.packer.get_buf()

    def turn_around(self):
        try:
            self.unpacker.done()
        except RuntimeError:
            raise GarbageArgs
        self.packer.pack_uint(SUCCESS)

    def handle_0(self): # Handle NULL message
        self.turn_around()

    def makesocket(self):
        # This MUST be overridden
        raise RuntimeError, 'makesocket not defined'

    def bindsocket(self):
        # Override this to bind to a different port (e.g. reserved)
        self.sock.bind((self.host, self.port))

    def addpackers(self):
        # Override this to use derived classes from Packer/Unpacker
        self.packer = Packer()
        self.unpacker = Unpacker('')


class TCPServer(Server):

    def makesocket(self):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.prot = IPPROTO_TCP

    def loop(self):
        self.sock.listen(0)
        while 1:
            self.session(self.sock.accept())

    def session(self, connection):
        sock, (host, port) = connection
        while 1:
            try:
                call = recvrecord(sock)
            except EOFError:
                break
            except socket.error, msg:
                print 'socket error:', msg
                break
            reply = self.handle(call)
            if reply is not None:
                sendrecord(sock, reply)

    def forkingloop(self):
        # Like loop but uses forksession()
        self.sock.listen(0)
        while 1:
            self.forksession(self.sock.accept())

    def forksession(self, connection):
        # Like session but forks off a subprocess
        import os
        # Wait for deceased children
        try:
            while 1:
                pid, sts = os.waitpid(0, 1)
        except os.error:
            pass
        pid = None
        try:
            pid = os.fork()
            if pid: # Parent
                connection[0].close()
                return
            # Child
            self.session(connection)
        finally:
            # Make sure we don't fall through in the parent
            if pid == 0:
                os._exit(0)


class UDPServer(Server):

    def makesocket(self):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        self.prot = IPPROTO_UDP

    def loop(self):
        while 1:
            self.session()

    def session(self):
        call, host_port = self.sock.recvfrom(8192)
        reply = self.handle(call)
        if reply is not None:
            self.sock.sendto(reply, host_port)


# Simple test program -- dump local portmapper status

def test():
    pmap = UDPPortMapperClient('')
    list = pmap.Dump()
    list.sort()
    for prog, vers, prot, port in list:
        print prog, vers,
        if prot == IPPROTO_TCP: print 'tcp',
        elif prot == IPPROTO_UDP: print 'udp',
        else: print prot,
        print port


# Test program for broadcast operation -- dump everybody's portmapper status

def testbcast():
    import sys
    if sys.argv[1:]:
        bcastaddr = sys.argv[1]
    else:
        bcastaddr = '<broadcast>'
    def rh(reply, fromaddr):
        host, port = fromaddr
        print host + '\t' + repr(reply)
    pmap = BroadcastUDPPortMapperClient(bcastaddr)
    pmap.set_reply_handler(rh)
    pmap.set_timeout(5)
    replies = pmap.Getport((100002, 1, IPPROTO_UDP, 0))


# Test program for server, with corresponding client
# On machine A: python -c 'import rpc; rpc.testsvr()'
# On machine B: python -c 'import rpc; rpc.testclt()' A
# (A may be == B)

def testsvr():
    # Simple test class -- proc 1 doubles its string argument as reply
    class S(UDPServer):
        def handle_1(self):
            arg = self.unpacker.unpack_string()
            self.turn_around()
            print 'RPC function 1 called, arg', repr(arg)
            self.packer.pack_string(arg + arg)
    #
    s = S('', 0x20000000, 1, 0)
    try:
        s.unregister()
    except RuntimeError, msg:
        print 'RuntimeError:', msg, '(ignored)'
    s.register()
    print 'Service started...'
    try:
        s.loop()
    finally:
        s.unregister()
        print 'Service interrupted.'


def testclt():
    import sys
    if sys.argv[1:]: host = sys.argv[1]
    else: host = ''
    # Client for above server
    class C(UDPClient):
        def call_1(self, arg):
            return self.make_call(1, arg, \
                    self.packer.pack_string, \
                    self.unpacker.unpack_string)
    c = C(host, 0x20000000, 1)
    print 'making call...'
    reply = c.call_1('hello, world, ')
    print 'call returned', repr(reply)