Imported nxcomp-3.1.0-4.tar.gznxcomp/3.1.0-4

Summary: Imported nxcomp-3.1.0-4.tar.gz
Keywords:

Imported nxcomp-3.1.0-4.tar.gz
into Git repository

1 files changed, 1263 insertions, 0 deletions

diff --git a/nxcomp/Proxy.h b/nxcomp/Proxy.h
new file mode 100755
index 000000000..54187a8ec
--- /dev/null
+++ b/nxcomp/Proxy.h
@@ -0,0 +1,1263 @@
+/**************************************************************************/
+/*                                                                        */
+/* Copyright (c) 2001, 2007 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 NoMachine S.r.l.                    */
+/*                                                                        */
+/* 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 */