aboutsummaryrefslogtreecommitdiff
path: root/nxcomp/Proxy.h
blob: 8fd2b7d176ea46854af141be94ec1bf9e2d32b7b (plain)
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
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
/**************************************************************************/
/*                                                                        */
/* Copyright (c) 2001, 2009 NoMachine, http://www.nomachine.com/.         */
/*                                                                        */
/* NXCOMP, NX protocol compression and NX extensions to this software     */
/* are copyright of NoMachine. Redistribution and use of the present      */
/* software is allowed according to terms specified in the file LICENSE   */
/* which comes in the source distribution.                                */
/*                                                                        */
/* Check http://www.nomachine.com/licensing.html for applicability.       */
/*                                                                        */
/* NX and NoMachine are trademarks of Medialogic S.p.A.                   */
/*                                                                        */
/* All rights reserved.                                                   */
/*                                                                        */
/**************************************************************************/

#ifndef Proxy_H
#define Proxy_H

#include <sys/types.h>

#ifdef _AIX
#include <sys/select.h>
#endif

#include "Misc.h"
#include "Timestamp.h"

#include "List.h"
#include "Channel.h"
#include "Transport.h"
#include "EncodeBuffer.h"
#include "ProxyReadBuffer.h"

//
// Forward declaration as we
// need a pointer.
//

class Agent;

//
// Set the verbosity level.
//

#define PANIC
#define WARNING
#undef  TEST
#undef  DEBUG

//
// Log the important tracepoints related
// to writing packets to the peer proxy.
//

#undef  FLUSH

//
// Codes used for control messages in
// proxy-to-proxy protocol.
//
// The following codes are currently
// unused.
//
// code_alert_reply,
// code_reset_request,
// code_reset_reply,
// code_load_reply,
// code_save_reply,
// code_shutdown_reply,
// code_configuration_request,
// code_configuration_reply.
//
// These are for compatibility with
// old versions.
//
// code_sync_request,
// code_sync_reply,
//
// The code_new_aux_connection should not
// be used anymore. Auxiliary X connections
// are treated as normal X channels since
// version 1.5.0.
//

typedef enum
{
  code_new_x_connection,
  code_new_cups_connection,
  code_new_aux_connection,
  code_new_smb_connection,
  code_new_media_connection,
  code_switch_connection,
  code_drop_connection,
  code_finish_connection,
  code_begin_congestion,
  code_end_congestion,
  code_alert_request,
  code_alert_reply,
  code_reset_request,
  code_reset_reply,
  code_load_request,
  code_load_reply,
  code_save_request,
  code_save_reply,
  code_shutdown_request,
  code_shutdown_reply,
  code_control_token_request,
  code_control_token_reply,
  code_configuration_request,
  code_configuration_reply,
  code_statistics_request,
  code_statistics_reply,
  code_new_http_connection,
  code_sync_request,
  code_sync_reply,
  code_new_font_connection,
  code_new_slave_connection,
  code_finish_listeners,
  code_split_token_request,
  code_split_token_reply,
  code_data_token_request,
  code_data_token_reply,
  code_last_tag

} T_proxy_code;

typedef enum
{
  operation_in_negotiation,
  operation_in_messages,
  operation_in_configuration,
  operation_in_statistics,
  operation_last_tag

} T_proxy_operation;

typedef enum
{
  frame_ping,
  frame_data,

} T_frame_type;

typedef enum
{
  token_control,
  token_split,
  token_data

} T_token_type;

typedef enum
{
  load_if_any,
  load_if_first

} T_load_type;

class Proxy
{
  public:

  //
  // Maximum number of supported channels.
  //

  static const int CONNECTIONS_LIMIT  = 256;

  //
  // Numboer of token types.
  //

  static const int TOKEN_TYPES = 3;

  //
  // Lenght of buffer we use to add our
  // control messages plus the length of
  // the data frame.
  //

  static const int CONTROL_CODES_LENGTH = ENCODE_BUFFER_PREFIX_SIZE - 5;

  static const int CONTROL_CODES_THRESHOLD = CONTROL_CODES_LENGTH - 9;

  Proxy(int fd);

  virtual ~Proxy();

  //
  // Inform the proxy that the negotiation phase is
  // completed and that it can start handling binary
  // messages.
  //

  int setOperational();

  int getOperational()
  {
    return (operation_ != operation_in_negotiation);
  }

  int setReadDescriptors(fd_set *fdSet, int &fdMax, T_timestamp &tsMax);

  int setWriteDescriptors(fd_set *fdSet, int &fdMax, T_timestamp &tsMax);

  //
  // Perform the operation on the proxy
  // link or its own channels.
  //

  int handleRead(int &resultFds, fd_set &fdSet);

  int handleFlush(int &resultFds, fd_set &fdSet);

  int handleRead();

  int handleRead(int fd, const char *data = NULL, int size = 0);

  int handleEvents();

  int handleFlush();

  int handleFlush(int fd);

  int handlePing();

  int handleFinish();

  int handleShutdown();

  int handleStatistics(int type, ostream *statofs);

  int handleAlert(int alert);

  int handleRotate()
  {
    activeChannels_.rotate();

    return 1;
  }

  int handleChannelConfiguration();

  int handleSocketConfiguration();

  int handleLinkConfiguration();

  int handleCacheConfiguration();

  //
  // These must be called just after initialization to
  // tell to the proxy where the network connections
  // have to be forwarded.
  //

  virtual void handleDisplayConfiguration(const char *xServerDisplay, int xServerAddrFamily,
                                              sockaddr * xServerAddr, unsigned int xServerAddrLength) = 0;

  virtual void handlePortConfiguration(int cupsServerPort, int smbServerPort, int mediaServerPort,
                                           int httpServerPort, const char *fontServerPort) = 0;

  //
  // Create new tunneled channels.
  //

  virtual int handleNewConnection(T_channel_type type, int clientFd) = 0;

  virtual int handleNewConnectionFromProxy(T_channel_type type, int channelId) = 0;

  virtual int handleNewAgentConnection(Agent *agent) = 0;

  virtual int handleNewXConnection(int clientFd) = 0;

  virtual int handleNewXConnectionFromProxy(int channelId) = 0;

  int handleNewGenericConnection(int clientFd, T_channel_type type, const char *label);

  int handleNewGenericConnectionFromProxy(int channelId, T_channel_type type,
                                              const char *hostname, int port, const char *label);

  int handleNewGenericConnectionFromProxy(int channelId, T_channel_type type,
                                              const char *hostname, const char *path, const char *label);

  int handleNewSlaveConnection(int clientFd);

  int handleNewSlaveConnectionFromProxy(int channelId);

  //
  // Force closure of channels.
  //

  int handleCloseConnection(int clientFd);

  int handleCloseAllXConnections();

  int handleCloseAllListeners();

  //
  // Called when the loop has replaced
  // or closed a previous alert.
  //

  void handleResetAlert();

  //
  // Handle the persistent cache.
  //

  virtual int handleLoad(T_load_type type) = 0;

  virtual int handleSave() = 0;

  protected:

  //
  // Timeout related data:
  //
  // flush
  // split
  // motion
  //
  // Timeouts in milliseconds after which the
  // proxy will have to perform the operation.
  //
  // readTs, writeTs
  //
  // Timestamp of last packet received or sent
  // to remote proxy. Used to detect lost con-
  // nection.
  //
  // loopTs
  //
  // Timestamp of last loop completed by the
  // proxy
  //
  // pingTs
  //
  // Timestamp of last ping request sent to the
  // remote peer.
  //
  // alertTs
  //
  // Timestamp of last 'no data received' alert
  // dialog shown to the user.
  //
  // loadTs
  //
  // Were message stores populated from data on
  // disk.
  //
  // splitTs
  // motionTs
  //
  // Timestamps of the last operation of this
  // kind handled by the proxy.
  //

  typedef struct
  {
    int split;
    int motion;

    T_timestamp readTs;
    T_timestamp writeTs;

    T_timestamp loopTs;
    T_timestamp pingTs;
    T_timestamp alertTs;
    T_timestamp loadTs;

    T_timestamp splitTs;
    T_timestamp motionTs;

  } T_proxy_timeouts;

  //
  // Bytes accumulated so far while waiting
  // to send the next token, number of tokens
  // remaining for each token type and other
  // token related information.
  //

  typedef struct
  {
    int size;
    int limit;

    int bytes;
    int remaining;

    T_proxy_code request;
    T_proxy_code reply;

    T_token_type type;

  } T_proxy_token;

  int handlePostConnectionFromProxy(int channelId, int serverFd,
                                        T_channel_type type, const char *label);

  int handleDrain();

  int handleFrame(T_frame_type type);

  int handleFinish(int channelId);

  int handleDrop(int channelId);

  int handleFinishFromProxy(int channelId);

  int handleDropFromProxy(int channelId);

  int handleStatisticsFromProxy(int type);

  int handleStatisticsFromProxy(const unsigned char *message, unsigned int length);

  int handleNegotiation(const unsigned char *message, unsigned int length);

  int handleNegotiationFromProxy(const unsigned char *message, unsigned int length);

  int handleToken(T_frame_type type);

  int handleTokenFromProxy(T_proxy_token &token, int count);

  int handleTokenReplyFromProxy(T_proxy_token &token, int count);

  int handleSyncFromProxy(int channelId);

  int handleSwitch(int channelId);

  int handleControl(T_proxy_code code, int data = -1);

  int handleControlFromProxy(const unsigned char *message);

  //
  // Interleave reads of the X server
  // events while writing data to the
  // remote proxy.
  //

  virtual int handleAsyncEvents() = 0;

  //
  // Timer related functions.
  //

  protected:

  void setTimer(int value)
  {
    SetTimer(value);
  }

  void resetTimer()
  {
    ResetTimer();

    timer_ = 0;
  }

  public:

  void handleTimer()
  {
    timer_ = 1;
  }

  int getTimer()
  {
    return timer_;
  }

  //
  // Can the channel consume data and the
  // proxy produce more output?
  //

  int canRead(int fd) const
  {
    return (isTimeToRead() == 1 &&
                isTimeToRead(getChannel(fd)) == 1);
  }

  //
  // Can the proxy read more data from its
  // peer?
  //

  int canRead() const
  {
    return (transport_ -> readable() != 0);
  }

  int canFlush() const
  {
    return (encodeBuffer_.getLength() +
                controlLength_ + transport_ -> length() +
                    transport_ -> flushable() > 0);
  }

  int needFlush(int channelId) const
  {
    return (outputChannel_ == channelId &&
                encodeBuffer_.getLength() > 0);
  }

  int needFlush() const
  {
    return (encodeBuffer_.getLength() > 0);
  }

  int shouldFlush() const
  {
    if ((int) ((encodeBuffer_.getLength() +
            controlLength_) / statistics ->
                getStreamRatio()) >= control -> TokenSize)
    {
      #if defined(TEST) || defined(INFO) || defined(FLUSH)
      *logofs << "Proxy: FLUSH! Requesting a flush with "
              << (encodeBuffer_.getLength() + controlLength_)
              << " bytes and stream ratio " << (double) statistics ->
                 getStreamRatio() << ".\n" << logofs_flush;
      #endif

      return 1;
    }

    #if defined(TEST) || defined(INFO) || defined(FLUSH)
    *logofs << "Proxy: Not requesting a flush with "
            << (encodeBuffer_.getLength() + controlLength_)
            << " bytes and stream ratio " << (double) statistics ->
               getStreamRatio() << ".\n" << logofs_flush;
    #endif

    return 0;
  }

  int needDrain() const
  {
    return (congestion_ == 1 || transport_ -> length() >
                control -> TransportProxyBufferThreshold);
  }

  int getFd() const
  {
    return fd_;
  }

  int getFlushable(int fd) const
  {
    if (fd == fd_)
    {
      return (encodeBuffer_.getLength() + controlLength_ +
                  transport_ -> flushable());
    }

    return 0;
  }

  int getSplitSize()
  {
    return (clientStore_ != NULL ? clientStore_ ->
                getSplitTotalSize() : 0);
  }

  int getSplitStorageSize()
  {
    return (clientStore_ != NULL ? clientStore_ ->
                getSplitTotalStorageSize() : 0);
  }

  //
  // Returns the number of active channels
  // that currently managed by this proxy.
  //

  int getChannels(T_channel_type type = channel_none);

  //
  // If descriptor corresponds to a valid
  // channel, returns the type of traffic
  // carried by it.
  //

  T_channel_type getType(int fd);

  //
  // Given a channel type, returns the
  // literal name.
  //

  const char *getTypeName(T_channel_type type);

  //
  // Get a convenient name for 'localhost'.
  //

  const char *getComputerName();

  //
  // Set if we have initiated the shutdown
  // procedure and if the shutdown request
  // has been received from the remote.
  //

  int getFinish() const
  {
    return finish_;
  }

  int getShutdown() const
  {
    return shutdown_;
  }

  //
  // Interfaces to the transport buffers.
  //

  int getLength(int fd) const
  {
    if (fd == fd_)
    {
      return transport_ -> length();
    }

    int channelId = getChannel(fd);

    if (channelId < 0 || channels_[channelId] == NULL)
    {
      return 0;
    }

    return transports_[channelId] -> length();
  }

  int getPending(int fd) const
  {
    if (fd == fd_)
    {
      return transport_ -> pending();
    }

    int channelId = getChannel(fd);

    if (channelId < 0 || channels_[channelId] == NULL)
    {
      return 0;
    }

    return transports_[channelId] -> pending();
  }

  //
  // Check if the proxy or the given channel
  // has data in the buffer because of a
  // blocking write.
  //

  int getBlocked(int fd) const
  {
    if (fd == fd_)
    {
      return transport_ -> blocked();
    }

    int channelId = getChannel(fd);

    if (channelId < 0 || channels_[channelId] == NULL)
    {
      return 0;
    }

    return transports_[channelId] -> blocked();
  }

  //
  // Check if the proxy or the given channel has
  // data to read.
  //

  int getReadable(int fd) const
  {
    if (fd == fd_)
    {
      return transport_ -> readable();
    }

    int channelId = getChannel(fd);

    if (channelId < 0 || channels_[channelId] == NULL)
    {
      return 0;
    }

    return transports_[channelId] -> readable();
  }

  //
  // Return a vale between 0 and 9 in the case
  // of the proxy descriptor.
  //

  int getCongestion(int fd) const
  {
    if (fd == fd_)
    {
      return (agent_ != nothing && congestions_[agent_] == 1 ? 9 :
                  (int) statistics -> getCongestionInFrame());
    }

    int channelId = getChannel(fd);

    if (channelId < 0 || channels_[channelId] == NULL)
    {
      return 0;
    }

    return channels_[channelId] -> getCongestion();
  }

  //
  // Let the statistics class get info
  // from the message stores.
  //

  const ClientStore * const getClientStore() const
  {
    return clientStore_;
  }

  const ServerStore * const getServerStore() const
  {
    return serverStore_;
  }

  //
  // These can be called asynchronously by
  // channels during their read or write
  // loop.
  //

  int handleAsyncRead(int fd)
  {
    return handleRead(fd);
  }

  int handleAsyncCongestion(int fd)
  {
    int channelId = getChannel(fd);

    return handleControl(code_begin_congestion, channelId);
  }

  int handleAsyncDecongestion(int fd)
  {
    int channelId = getChannel(fd);

    return handleControl(code_end_congestion, channelId);
  }

  int handleAsyncSplit(int fd, Split *split)
  {
    return channels_[getChannel(fd)] ->
               handleSplitEvent(encodeBuffer_, split);
  }

  int handleAsyncInit()
  {
    return handleFlush();
  }

  int handleAsyncPriority()
  {
    if (control -> FlushPriority == 1)
    {
      return handleFlush();
    }

    return 0;
  }

  int canAsyncFlush() const
  {
    return shouldFlush();
  }

  int handleAsyncFlush()
  {
    return handleFlush();
  }

  int handleAsyncSwitch(int fd)
  {
    return handleSwitch(getChannel(fd));
  }

  int handleAsyncKeeperCallback()
  {
    KeeperCallback();

    return 1;
  }

  //
  // Internal interfaces used to verify the
  // availability of channels and the proxy
  // link.
  //

  protected:

  int isTimeToRead() const
  {
    if (congestion_ == 0 && transport_ ->
            blocked() == 0)
    {
      return 1;
    }
    else
    {
      #if defined(TEST) || defined(INFO)
      *logofs << "Proxy: Can't read from channels "
              << "with congestion " << congestion_
              << " and blocked " << transport_ ->
                 blocked() << ".\n" << logofs_flush;
      #endif

      return 0;
    }
  }

  int isTimeToRead(int channelId) const
  {
    if (channelId >= 0 && channelId < CONNECTIONS_LIMIT &&
            channels_[channelId] != NULL &&
                congestions_[channelId] == 0)
    {
      if (channels_[channelId] -> getType() == channel_x11 ||
              tokens_[token_data].remaining > 0 ||
                  channels_[channelId] ->
                      getFinish() == 1)
      {
        return 1;
      }

      #if defined(TEST) || defined(INFO)
      *logofs << "Proxy: Can't read from generic "
              << "descriptor FD#" << getFd(channelId)
              << " channel ID#" << channelId << " with "
              << tokens_[token_data].remaining
              << " data tokens remaining.\n"
              << logofs_flush;
      #endif

      return 0;
    }

    #if defined(TEST) || defined(INFO)

    if (channelId < 0 || channelId >= CONNECTIONS_LIMIT ||
            channels_[channelId] == NULL)
    {
      *logofs << "Proxy: WARNING! No valid channel for ID#"
              << channelId << ".\n" << logofs_flush;
    }
    else if (channels_[channelId] -> getFinish())
    {
      *logofs << "Proxy: Can't read from finishing "
              << "descriptor FD#" << getFd(channelId)
              << " channel ID#" << channelId << ".\n"
              << logofs_flush;
    }
    else if (congestions_[channelId] == 1)
    {
      *logofs << "Proxy: Can't read from congested "
              << "descriptor FD#" << getFd(channelId)
              << " channel ID#" << channelId << ".\n"
              << logofs_flush;
    }

    #endif

    return 0;
  }

  //
  // Handle the flush and split timeouts.
  // All these functions should round up
  // to the value of the latency timeout
  // to save a further loop.
  //

  protected:

  int isTimeToSplit() const
  {
    if (isTimestamp(timeouts_.splitTs) &&
            getTimeToNextSplit() <= control ->
                LatencyTimeout)
    {
      if (tokens_[token_split].remaining > 0)
      {
        return 1;
      }

      #if defined(TEST) || defined(INFO)
      *logofs << "Proxy: WARNING! Can't encode splits "
              << "with " << tokens_[token_split].remaining
              << " split tokens remaining.\n"
              << logofs_flush;
      #endif
    }

    return 0;
  }

  int isTimeToMotion() const
  {
    return (isTimestamp(timeouts_.motionTs) &&
                getTimeToNextMotion() <= control ->
                    LatencyTimeout);
  }

  int getTimeToNextSplit() const
  {
    #if defined(TEST) || defined(INFO) || defined(FLUSH)

    if (isTimestamp(timeouts_.splitTs) == 0)
    {
      #ifdef PANIC
      *logofs << "Proxy: PANIC! No split timeout was set "
              << "for proxy FD#" << fd_ << ".\n"
              << logofs_flush;
      #endif

      cerr << "Error" << ": No split timeout was set "
           << "for proxy FD#" << fd_ << ".\n";

      HandleCleanup();
    }

    #endif

    int diffTs = timeouts_.split -
                     diffTimestamp(timeouts_.splitTs,
                         getTimestamp());

    return (diffTs > 0 ? diffTs : 0);
  }

  int getTimeToNextMotion() const
  {
    #if defined(TEST) || defined(INFO) || defined(FLUSH)

    if (isTimestamp(timeouts_.motionTs) == 0)
    {
      #ifdef PANIC
      *logofs << "Proxy: PANIC! No motion timeout was set "
              << "for proxy FD#" << fd_ << ".\n"
              << logofs_flush;
      #endif

      cerr << "Error" << ": No motion timeout was set "
           << "for proxy FD#" << fd_ << ".\n";

      HandleCleanup();
    }

    #endif

    int diffTs = timeouts_.motion -
                     diffTimestamp(timeouts_.motionTs,
                         getTimestamp());

    return (diffTs > 0 ? diffTs : 0);
  }

  protected:

  //
  // Implement persistence of cache on disk.
  //

  virtual int handleLoadFromProxy() = 0;
  virtual int handleSaveFromProxy() = 0;

  int handleLoadStores();
  int handleSaveStores();

  char *handleSaveAllStores(const char *savePath) const;

  virtual int handleSaveAllStores(ostream *cachefs, md5_state_t *md5StateStream,
                                      md5_state_t *md5StateClient) const = 0;

  int handleSaveVersion(unsigned char *buffer, int &major, int &minor, int &patch) const;

  void handleFailOnSave(const char *fullName, const char *failContext) const;

  const char *handleLoadAllStores(const char *loadPath, const char *loadName) const;

  virtual int handleLoadAllStores(istream *cachefs, md5_state_t *md5StateStream) const = 0;

  int handleLoadVersion(const unsigned char *buffer, int &major, int &minor, int &patch) const;

  void handleFailOnLoad(const char *fullName, const char *failContext) const;

  //
  // Prepare for a new persistent cache.
  //

  int handleResetPersistentCache();

  //
  // Reset the stores in the case of a
  // failure loading the cache.
  //

  int handleResetStores();

  //
  // Reset the transport buffer and the
  // other counters.
  //

  void handleResetFlush();

  //
  // Utility functions used to map file
  // descriptors to channel ids.
  //

  protected:

  int allocateChannelMap(int fd);
  int checkChannelMap(int channelId);
  int assignChannelMap(int channelId, int fd);

  void cleanupChannelMap(int channelId);

  virtual int checkLocalChannelMap(int channelId) = 0;

  int addControlCodes(T_proxy_code code, int data);
  int addTokenCodes(T_proxy_token &token);

  int getFd(int channelId) const
  {
    if (channelId >= 0 && channelId < CONNECTIONS_LIMIT)
    {
      return fdMap_[channelId];
    }

    return -1;
  }

  int getChannel(int fd) const
  {
    if (fd >= 0 && fd < CONNECTIONS_LIMIT)
    {
      return channelMap_[fd];
    }

    return -1;
  }

  protected:

  void setSplitTimeout(int channelId);
  void setMotionTimeout(int channelId);

  void increaseChannels(int channelId);
  void decreaseChannels(int channelId);

  int allocateTransport(int channelFd, int channelId);
  int deallocateTransport(int channelId);

  //
  // The proxy has its own transport.
  //

  ProxyTransport *transport_;

  //
  // The static compressor is shared among
  // channels and all the message stores.
  //

  StaticCompressor *compressor_;

  //
  // Map NX specific opcodes.
  //

  OpcodeStore *opcodeStore_;

  //
  // Stores are shared between channels.
  //

  ClientStore *clientStore_;
  ServerStore *serverStore_;

  //
  // Client and server caches are shared
  // between channels.
  //

  ClientCache *clientCache_;
  ServerCache *serverCache_;

  //
  // The proxy's file descriptor.
  //

  int fd_;

  //
  // Channels currently selected for I/O
  // operations.
  //

  int inputChannel_;
  int outputChannel_;

  //
  // List of active channels.
  //

  List activeChannels_;

  //
  // Used to read data sent from peer proxy.
  //

  ProxyReadBuffer readBuffer_;

  //
  // Used to send data to peer proxy.
  //

  EncodeBuffer encodeBuffer_;

  //
  // Control messages' array.
  //

  int controlLength_;

  unsigned char controlCodes_[CONTROL_CODES_LENGTH];

  //
  // Table of channel classes taking
  // care of open X connections.
  //

  Channel *channels_[CONNECTIONS_LIMIT];

  //
  // Table of open sockets.
  //

  Transport *transports_[CONNECTIONS_LIMIT];

  //
  // Timeout related data.
  //

  T_proxy_timeouts timeouts_;

  //
  // Proxy can be decoding messages,
  // handling a link reconfiguration,
  // or decoding statistics.
  //

  int operation_;

  //
  // True if we are currently draining
  // the proxy link.
  //

  int draining_;

  //
  // Force flush because of prioritized
  // control messages to send.
  //

  int priority_;

  //
  // Set if we have initiated the close
  // down procedure.
  //

  int finish_;

  //
  // Remote peer requested the shutdown.
  //

  int shutdown_;

  //
  // We are in the middle of a network
  // congestion in the path to remote
  // proxy.
  //

  int congestion_;

  //
  // Channels at the remote end that
  // are not consuming their data.
  //

  int congestions_[CONNECTIONS_LIMIT];

  //
  // Is the timer expired?
  //

  int timer_;

  //
  // Did the proxy request an alert?
  //

  int alert_;

  //
  // The channel id of the agent.
  //

  int agent_;

  //
  // Token related data.
  //

  T_proxy_token tokens_[TOKEN_TYPES];

  //
  // Pointer to stream descriptor where
  // proxy is producing statistics.
  //

  ostream *currentStatistics_;

  private:

  //
  // Map channel ids to file descriptors.
  //

  int channelMap_[CONNECTIONS_LIMIT];
  int fdMap_[CONNECTIONS_LIMIT];
};

#endif /* Proxy_H */