TNL::NetConnection class Reference

TNL::NetConnection Class Reference

#include <tnlNetConnection.h>

Inheritance diagram for TNL::NetConnection:

Detailed Description

TNL network connection base class.

NetConnection is the base class for the connection classes in TNL. It implements a notification protocol on the unreliable packet transport of UDP (via the TNL::Net layer). NetConnection manages the flow of packets over the network, and calls its subclasses to read and write packet data, as well as handle packet delivery notification.

Because string data can easily soak up network bandwidth, for efficiency NetConnection implements an optional networked string table. Users can then notify the connection of strings it references often, such as player names, and transmit only a tag, instead of the whole string.

Adaptive Protocol

Functions and state for the adaptive rate protocol.
TNL's adaptive rate uses rate control algorithms similar to TCP/IP's.
There are a few state variables here that aren't documented.

void setIsAdaptive ()

Enables the adaptive protocol.

void setFixedRateParameters (U32 minPacketSendPeriod, U32 minPacketRecvPeriod, U32 maxSendBandwidth, U32 maxRecvBandwidth)

sets the fixed rate send and receive data sizes, and sets the connection to not behave as an adaptive rate connection

bool isAdaptive ()

Query the adaptive status of the connection.

virtual bool isDataToTransmit ()

Returns true if this connection has data to transmit.

F32 cwnd

F32 ssthresh

U32 mLastSeqRecvdAck

U32 mLastAckTime

Public Types

enum TerminationReason {
  ReasonTimedOut,
  ReasonFailedConnectHandshake,
  ReasonRemoteHostRejectedConnection,
  ReasonRemoteDisconnectPacket,
  ReasonDuplicateConnectionAttempt,
  ReasonSelfDisconnect,
  ReasonError
}

enum NetConnectionTypeFlags {
  ConnectionToServer = BIT(0),
  ConnectionToClient = BIT(1),
  ConnectionAdaptive = BIT(2),
  ConnectionRemoteAdaptive = BIT(3)
}

Flags specifying the type of the connection instance. More...

enum NetConnectionState {
  NotConnected = 0,
  AwaitingChallengeResponse,
  SendingPunchPackets,
  ComputingPuzzleSolution,
  AwaitingConnectResponse,
  ConnectTimedOut,
  ConnectRejected,
  Connected,
  Disconnected,
  TimedOut,
  StateCount
}

Connection state flags for a NetConnection instance. More...

Public Member Functions

NetConnection ()

~NetConnection ()

U32 getNextSendSequence ()

Returns the next send sequence that will be sent by this side.

U32 getLastSendSequence ()

Returns the sequence of the last packet sent by this connection, or the current packet's send sequence if called from within writePacket().

void setInitialRecvSequence (U32 sequence)

Sets the initial sequence number of packets read from the remote host.

U32 getInitialRecvSequence ()

Returns the initial sequence number of packets sent from the remote host.

U32 getInitialSendSequence ()

Returns the initial sequence number of packets sent to the remote host.

void connect (NetInterface *connectionInterface, const Address &address, bool requestKeyExchange=false, bool requestCertificate=false)

Connect to a server through a given network interface.

bool connectLocal (NetInterface *connectionInterface, NetInterface *localServerInterface)

Connects to a server interface within the same process.

void connectArranged (NetInterface *connectionInterface, const Vector< Address > &possibleAddresses, Nonce &myNonce, Nonce &remoteNonce, ByteBufferPtr sharedSecret, bool isInitiator, bool requestsKeyExchange=false, bool requestsCertificate=false)

Connects to a remote host that is also connecting to this connection (negotiated by a third party).

void disconnect (const char *reason)

Sends a disconnect packet to notify the remote host that this side is terminating the connection for the specified reason.

bool windowFull ()

Returns true if the packet send window is full and no more data packets can be sent.

ConnectionParameters & getConnectionParameters ()

bool isInitiator ()

returns true if this object initiated the connection with the remote host

void setRemoteConnectionObject (NetConnection *connection)

NetConnection * getRemoteConnectionObject ()

void setInterface (NetInterface *myInterface)

Sets the NetInterface this NetConnection will communicate through.

NetInterface * getInterface ()

Returns the NetInterface this connection communicates through.

void setSymmetricCipher (SymmetricCipher *theCipher)

Sets the SymmetricCipher this NetConnection will use for encryption.

virtual NetClassGroup getNetClassGroup () const

Returns the class group of objects that can be transmitted over this NetConnection.

void setPingTimeouts (U32 msPerPing, U32 pingRetryCount)

Sets the ping/timeout characteristics for a fixed-rate connection. Total timeout is msPerPing * pingRetryCount.

void setSimulatedNetParams (F32 packetLoss, U32 latency)

Simulates a network situation with a percentage random packet loss and a connection one way latency as specified.

void setIsConnectionToServer ()

Specifies that this NetConnection instance is a connection to a "server.".

bool isConnectionToServer ()

Returns true if this is a connection to a "server.".

void setIsConnectionToClient ()

Specifies that this NetConnection instance is a connection to a "client.".

bool isConnectionToClient ()

Returns true if this is a connection to a "client.".

bool isLocalConnection ()

Returns true if the remote side of this connection is a NetConnection instance in on the same host.

bool isNetworkConnection ()

Returns true if the remote side if this connection is on a remote host.

F32 getRoundTripTime ()

Returns the running average packet round trip time.

F32 getOneWayTime ()

Returns have of the average of the round trip packet time.

const Address & getNetAddress ()

Returns the remote address of the host we're connected or trying to connect to.

const char * getNetAddressString () const

Returns the remote address in string form.

void setNetAddress (const Address &address)

Sets the address of the remote host we want to connect to.

NetError sendPacket (BitStream *stream)

Sends a packet that was written into a BitStream to the remote host, or the mRemoteConnection on this host.

bool checkTimeout (U32 time)

Checks to see if the connection has timed out, possibly sending a ping packet to the remote host. Returns true if the connection timed out.

void checkPacketSend (bool force, U32 currentTime)

Checks to see if a packet should be sent at the currentTime to the remote host.

void setConnectionState (NetConnectionState state)

Sets the current connection state of this NetConnection.

NetConnectionState getConnectionState ()

Gets the current connection state of this NetConnection.

bool isEstablished ()

Returns true if the connection handshaking has completed successfully.

void setTranslatesStrings ()

Enables string tag translation on this connection.

Static Public Member Functions

char * getErrorBuffer ()

returns the current error buffer

void setLastError (const char *fmt,...)

Sets an error string and notifies the currently processing connection that it should terminate.

Data Fields

U32 mConnectSendCount

Number of challenge or connect requests sent to the remote host.

U32 mConnectLastSendTime

The send time of the last challenge or connect request.

NetConnectionState mConnectionState

Current state of this NetConnection.

Protected Member Functions

virtual void onConnectTerminated (TerminationReason reason, const char *rejectionString)

Called when a pending connection is terminated.

virtual void onConnectionTerminated (TerminationReason, const char *errorDisconnectString)

Called when this established connection is terminated for any reason.

virtual void onConnectionEstablished ()

Called when the connection is successfully established with the remote host.

virtual bool validateCertficate (Certificate *theCertificate, bool isInitiator)

validates that the given certificate is a valid certificate for this connection.

virtual bool validatePublicKey (AsymmetricKey *theKey, bool isInitiator)

Validates that the given public key is valid for this connection.

virtual void writeConnectRequest (BitStream *stream)

Fills the connect request packet with additional custom data (from a subclass).

virtual bool readConnectRequest (BitStream *stream, const char **errorString)

Called after this connection instance is created on a non-initiating host (server).

virtual void writeConnectAccept (BitStream *stream)

Writes any data needed to start the connection on the accept packet.

virtual bool readConnectAccept (BitStream *stream, const char **errorString)

Reads out the extra data read by writeConnectAccept and returns true if it is processed properly.

virtual void readPacket (BitStream *bstream)

Called to read a subclass's packet data from the packet.

virtual void prepareWritePacket ()

Called to prepare the connection for packet writing.

virtual void writePacket (BitStream *bstream, PacketNotify *note)

Called to write a subclass's packet data into the packet.

virtual void packetReceived (PacketNotify *note)

Called when the packet associated with the specified notify is known to have been received by the remote host.

virtual void packetDropped (PacketNotify *note)

Called when the packet associated with the specified notify is known to have been not received by the remote host.

virtual PacketNotify * allocNotify ()

Allocates a data record to track data sent on an individual packet.

void readRawPacket (BitStream *bstream)

Reads a raw packet from a BitStream, as dispatched from NetInterface.

void writeRawPacket (BitStream *bstream, NetPacketType packetType)

Writes a full packet of the specified type into the BitStream.

void writePacketHeader (BitStream *bstream, NetPacketType packetType)

Writes the notify protocol's packet header into the BitStream.

bool readPacketHeader (BitStream *bstream)

Reads a notify protocol packet header from the BitStream and returns true if it was a data packet that needs more processing.

void writePacketRateInfo (BitStream *bstream, PacketNotify *note)

Writes any packet send rate change information into the packet.

void readPacketRateInfo (BitStream *bstream)

Reads any packet send rate information requests from the packet.

void sendPingPacket ()

Sends a ping packet to the remote host, to determine if it is still alive and what its packet window status is.

void sendAckPacket ()

Sends an ack packet to the remote host, in response to receiving a ping packet.

void handleNotify (U32 sequence, bool recvd)

Dispatches a notify when a packet is ACK'd or NACK'd.

void keepAlive ()

Called when a packet is received to stop any timeout action in progress.

void clearAllPacketNotifies ()

Clears out the pending notify list.

PacketNotify * getCurrentWritePacketNotify ()

Returns the notify structure for the current packet write, or last written packet.

Protected Attributes

PacketNotify * mNotifyQueueHead

Linked list of structures representing the data in sent packets.

PacketNotify * mNotifyQueueTail

Tail of the notify queue linked list. New packets are added to the end of the tail.

SafePtr< NetConnection > mRemoteConnection

Safe pointer to a short-circuit remote connection on the same host.

ConnectionParameters mConnectionParameters

SafePtr< NetInterface > mInterface

The NetInterface of which this NetConnection is a member.

RefPtr< SymmetricCipher > mSymmetricCipher

The helper object that performs symmetric encryption on packets.

Static Protected Attributes

char mErrorBuffer [256]

String buffer that errors are written into.

Private Types

typedef Object Parent

enum HeaderConstants {
  MaxPacketWindowSizeShift = 5,
  MaxPacketWindowSize = (1 << MaxPacketWindowSizeShift),
  PacketWindowMask = MaxPacketWindowSize - 1,
  MaxAckMaskSize = 1 << (MaxPacketWindowSizeShift - 5),
  MaxAckByteCount = MaxAckMaskSize << 2,
  SequenceNumberBitSize = 11,
  SequenceNumberWindowSize = (1 << SequenceNumberBitSize),
  SequenceNumberMask = -SequenceNumberWindowSize,
  AckSequenceNumberBitSize = 10,
  AckSequenceNumberWindowSize = (1 << AckSequenceNumberBitSize),
  AckSequenceNumberMask = -AckSequenceNumberWindowSize,
  PacketHeaderBitSize = 3 + AckSequenceNumberBitSize + SequenceNumberBitSize,
  PacketHeaderByteSize = (PacketHeaderBitSize + 7) >> 3,
  PacketHeaderPadBits = (PacketHeaderByteSize << 3) - PacketHeaderBitSize,
  MessageSignatureBytes = 5
}

Constants controlling the data representation of each packet header. More...

enum NetPacketType {
  DataPacket,
  PingPacket,
  AckPacket,
  InvalidPacketType
}

Two-bit identifier for each connected packet. More...

enum DefaultPingConstants {
  AdaptiveInitialPingTimeout = 60000,
  AdaptivePingRetryCount = 4,
  DefaultPingTimeout = 5000,
  DefaultPingRetryCount = 10,
  AdaptiveUnackedSentPingTimeout = 3000
}

Constants controlling the behavior of pings and timeouts. More...

enum RateDefaults {
  DefaultFixedBandwidth = 2500,
  DefaultFixedSendPeriod = 96,
  MaxFixedBandwidth = 65535,
  MaxFixedSendPeriod = 2047
}

Private Member Functions

bool hasUnackedSentPackets ()

Returns true if this connection has sent packets that have not yet been acked by the remote host.

void computeNegotiatedRate ()

Called internally when the local or remote rate changes.

Private Attributes

U32 mLastPacketRecvTime

Time of the receipt of the last data packet.

U32 mLastSeqRecvdAtSend [MaxPacketWindowSize]

The sequence number of the last packet received from the remote host when we sent the packet with sequence X & PacketWindowMask.

U32 mLastSeqRecvd

The sequence number of the most recently received packet from the remote host.

U32 mHighestAckedSeq

The highest sequence number the remote side has acknowledged.

U32 mLastSendSeq

The sequence number of the last packet sent.

U32 mAckMask [MaxAckMaskSize]

long string of bits, each acking a packet sent by the remote host

U32 mLastRecvAckAck

The highest sequence this side knows the other side has received an ACK or NACK for.

U32 mInitialSendSeq

The first mLastSendSeq for this side of the connection.

U32 mInitialRecvSeq

The first mLastSeqRecvd (the first mLastSendSeq for the remote host).

U32 mHighestAckedSendTime

The send time of the highest packet sequence acked by the remote host.

U32 mPingTimeout

Milliseconds to wait before sending a ping packet.

U32 mPingRetryCount

Number of unacknowledged pings to send before timing out.

BitSet32 mTypeFlags

Flags describing the type of connection this is, OR'd from NetConnectionTypeFlags.

U32 mLastUpdateTime

The last time a packet was sent from this instance.

F32 mRoundTripTime

Running average round trip time.

U32 mSendDelayCredit

Metric to help compensate for irregularities on fixed rate packet sends.

U32 mSimulatedLatency

Amount of additional time this connection delays its packet sends to simulate latency in the connection.

F32 mSimulatedPacketLoss

Function to simulate packet loss on a network.

NetRate mLocalRate

Current communications rate negotiated for this connection.

NetRate mRemoteRate

Maximum allowable communications rate for this connection.

bool mLocalRateChanged

Set to true when the local connection's rate has changed.

U32 mCurrentPacketSendSize

Current size of each packet sent to the remote host.

U32 mCurrentPacketSendPeriod

Millisecond delay between sent packets.

Address mNetAddress

The network address of the host this instance is connected to.

U32 mPingSendCount

Number of unacknowledged ping packets sent to the remote host.

U32 mLastPingSendTime

Last time a ping packet was sent from this connection.

ConnectionStringTable * mStringTable

Helper for managing translation between global NetStringTable ids to local ids for this connection.

Friends

class NetInterface

class ConnectionStringTable

Member Typedef Documentation

typedef Object TNL::NetConnection::Parent [private]

Reimplemented in TNL::EventConnection, TNL::GhostConnection, and TNLTest::TestConnection.

Member Enumeration Documentation

enum TNL::NetConnection::HeaderConstants [private]

Constants controlling the data representation of each packet header.

Enumeration values:

MaxPacketWindowSizeShift Packet window size is 2^MaxPacketWindowSizeShift.

MaxPacketWindowSize Maximum number of packets in the packet window.

PacketWindowMask Mask for accessing the packet window.

MaxAckMaskSize Each ack word can ack 32 packets.

MaxAckByteCount The maximum number of ack bytes sent in each packet.

SequenceNumberBitSize Bit size of the send and sequence number.

SequenceNumberWindowSize Size of the send sequence number window.

SequenceNumberMask Mask used to reconstruct the full send sequence number of the packet from the partial sequence number sent.

AckSequenceNumberBitSize Bit size of the ack receive sequence number.

AckSequenceNumberWindowSize Size of the ack receive sequence number window.

AckSequenceNumberMask Mask used to reconstruct the full ack receive sequence number of the packet from the partial sequence number sent.

PacketHeaderBitSize Size, in bits, of the packet header sequence number section.

PacketHeaderByteSize Size, in bytes, of the packet header sequence number information.

PacketHeaderPadBits Padding bits to get header bytes to align on a byte boundary, for encryption purposes.

MessageSignatureBytes Special data bytes written into the end of the packet to guarantee data consistency.

enum TNL::NetConnection::NetPacketType [private]

Two-bit identifier for each connected packet.

Enumeration values:

DataPacket Standard data packet. Each data packet sent increments the current packet sequence number (mLastSendSeq).

PingPacket Ping packet, sent if this instance hasn't heard from the remote host for a while.
Sending a ping packet does not increment the packet sequence number.

AckPacket Packet sent in response to a ping packet. Sending an ack packet does not increment the sequence number.

InvalidPacketType

enum TNL::NetConnection::DefaultPingConstants [private]

Constants controlling the behavior of pings and timeouts.

Enumeration values:

AdaptiveInitialPingTimeout

AdaptivePingRetryCount

DefaultPingTimeout Default milliseconds to wait before sending a ping packet.

DefaultPingRetryCount Default number of unacknowledged pings to send before timing out.

AdaptiveUnackedSentPingTimeout

enum TNL::NetConnection::TerminationReason

Enumeration values:

ReasonTimedOut

ReasonFailedConnectHandshake

ReasonRemoteHostRejectedConnection

ReasonRemoteDisconnectPacket

ReasonDuplicateConnectionAttempt

ReasonSelfDisconnect

ReasonError

enum TNL::NetConnection::NetConnectionTypeFlags

Flags specifying the type of the connection instance.

Enumeration values:

ConnectionToServer A connection to a "server", used for directing NetEvents.

ConnectionToClient A connection to a "client".

ConnectionAdaptive Indicates that this connection uses the adaptive protocol.

ConnectionRemoteAdaptive Indicates that the remote side of this connection requested the adaptive protocol.

enum TNL::NetConnection::RateDefaults [private]

Enumeration values:

DefaultFixedBandwidth The default send/receive bandwidth - 2.5 Kb per second.

DefaultFixedSendPeriod The default delay between each packet send - approx 10 packets per second.

MaxFixedBandwidth The maximum bandwidth for a connection using the fixed rate transmission method.

MaxFixedSendPeriod The maximum period between packets in the fixed rate send transmission method.

enum TNL::NetConnection::NetConnectionState

Connection state flags for a NetConnection instance.

Enumeration values:

NotConnected Initial state of a NetConnection instance - not connected.

AwaitingChallengeResponse We've sent a challenge request, awaiting the response.

SendingPunchPackets The state of a pending arranged connection when both sides haven't heard from the other yet.

ComputingPuzzleSolution We've received a challenge response, and are in the process of computing a solution to its puzzle.

AwaitingConnectResponse We've received a challenge response and sent a connect request.

ConnectTimedOut The connection timed out during the connection process.

ConnectRejected The connection was rejected.

Connected We've accepted a connect request, or we've received a connect response accept.

Disconnected The connection has been disconnected.

TimedOut The connection timed out.

StateCount

Constructor & Destructor Documentation

TNL::NetConnection::NetConnection ( )

TNL::NetConnection::~NetConnection ( )

Member Function Documentation

bool TNL::NetConnection::hasUnackedSentPackets ( ) [inline, private]

Returns true if this connection has sent packets that have not yet been acked by the remote host.

virtual void TNL::NetConnection::onConnectTerminated ( TerminationReason reason,

const char * rejectionString

) [protected, virtual]

Called when a pending connection is terminated.

virtual void TNL::NetConnection::onConnectionTerminated ( TerminationReason ,

const char * errorDisconnectString

) [protected, virtual]

Called when this established connection is terminated for any reason.

virtual void TNL::NetConnection::onConnectionEstablished ( ) [protected, virtual]

Called when the connection is successfully established with the remote host.

Reimplemented in TNLTest::TestConnection.

virtual bool TNL::NetConnection::validateCertficate ( Certificate * theCertificate,

bool isInitiator

) [inline, protected, virtual]

validates that the given certificate is a valid certificate for this connection.

virtual bool TNL::NetConnection::validatePublicKey ( AsymmetricKey * theKey,

bool isInitiator

) [inline, protected, virtual]

Validates that the given public key is valid for this connection.
If this host requires a valid certificate for the communication, this function should always return false. It will only be called if the remote side of the connection did not provide a certificate.

virtual void TNL::NetConnection::writeConnectRequest ( BitStream * stream ) [protected, virtual]

Fills the connect request packet with additional custom data (from a subclass).

Reimplemented in TNL::EventConnection.

virtual bool TNL::NetConnection::readConnectRequest ( BitStream * stream,

const char ** errorString

) [protected, virtual]

Called after this connection instance is created on a non-initiating host (server).
Reads data sent by the writeConnectRequest method and returns true if the connection is accepted or false if it's not. The errorString pointer should be filled if the connection is rejected.
Reimplemented in TNL::EventConnection.

virtual void TNL::NetConnection::writeConnectAccept ( BitStream * stream ) [protected, virtual]

Writes any data needed to start the connection on the accept packet.

Reimplemented in TNL::EventConnection.

virtual bool TNL::NetConnection::readConnectAccept ( BitStream * stream,

const char ** errorString

) [protected, virtual]

Reads out the extra data read by writeConnectAccept and returns true if it is processed properly.

Reimplemented in TNL::EventConnection.

virtual void TNL::NetConnection::readPacket ( BitStream * bstream ) [protected, virtual]

Called to read a subclass's packet data from the packet.

Reimplemented in TNL::EventConnection, and TNL::GhostConnection.

virtual void TNL::NetConnection::prepareWritePacket ( ) [protected, virtual]

Called to prepare the connection for packet writing.
Any setup work to determine if there isDataToTransmit() should happen in this function. prepareWritePacket should _always_ call the Parent:: function.
Reimplemented in TNL::GhostConnection.

virtual void TNL::NetConnection::writePacket ( BitStream * bstream,

PacketNotify * note

) [protected, virtual]

Called to write a subclass's packet data into the packet.
Information about what the instance wrote into the packet can be attached to the notify object.
Reimplemented in TNL::EventConnection, and TNL::GhostConnection.

virtual void TNL::NetConnection::packetReceived ( PacketNotify * note ) [protected, virtual]

Called when the packet associated with the specified notify is known to have been received by the remote host.
Packets are guaranteed to be notified in the order in which they were sent.
Reimplemented in TNL::EventConnection, and TNL::GhostConnection.

virtual void TNL::NetConnection::packetDropped ( PacketNotify * note ) [protected, virtual]

Called when the packet associated with the specified notify is known to have been not received by the remote host.
Packets are guaranteed to be notified in the order in which they were sent.
Reimplemented in TNL::EventConnection, and TNL::GhostConnection.

virtual PacketNotify* TNL::NetConnection::allocNotify ( ) [inline, protected, virtual]

Allocates a data record to track data sent on an individual packet.
If you need to track additional notification information, you'll have to override this so you allocate a subclass of PacketNotify with extra fields.
Reimplemented in TNL::EventConnection, and TNL::GhostConnection.

U32 TNL::NetConnection::getNextSendSequence ( ) [inline]

Returns the next send sequence that will be sent by this side.

U32 TNL::NetConnection::getLastSendSequence ( ) [inline]

Returns the sequence of the last packet sent by this connection, or the current packet's send sequence if called from within writePacket().

void TNL::NetConnection::readRawPacket ( BitStream * bstream ) [protected]

Reads a raw packet from a BitStream, as dispatched from NetInterface.

void TNL::NetConnection::writeRawPacket ( BitStream * bstream,

NetPacketType packetType

) [protected]

Writes a full packet of the specified type into the BitStream.

void TNL::NetConnection::writePacketHeader ( BitStream * bstream,

NetPacketType packetType

) [protected]

Writes the notify protocol's packet header into the BitStream.

bool TNL::NetConnection::readPacketHeader ( BitStream * bstream ) [protected]

Reads a notify protocol packet header from the BitStream and returns true if it was a data packet that needs more processing.

void TNL::NetConnection::writePacketRateInfo ( BitStream * bstream,

PacketNotify * note

) [protected]

Writes any packet send rate change information into the packet.

void TNL::NetConnection::readPacketRateInfo ( BitStream * bstream ) [protected]

Reads any packet send rate information requests from the packet.

void TNL::NetConnection::sendPingPacket ( ) [protected]

Sends a ping packet to the remote host, to determine if it is still alive and what its packet window status is.

void TNL::NetConnection::sendAckPacket ( ) [protected]

Sends an ack packet to the remote host, in response to receiving a ping packet.

void TNL::NetConnection::handleNotify ( U32 sequence,

bool recvd

) [protected]

Dispatches a notify when a packet is ACK'd or NACK'd.

void TNL::NetConnection::keepAlive ( ) [protected]

Called when a packet is received to stop any timeout action in progress.

void TNL::NetConnection::clearAllPacketNotifies ( ) [protected]

Clears out the pending notify list.

void TNL::NetConnection::setInitialRecvSequence ( U32 sequence )

Sets the initial sequence number of packets read from the remote host.

U32 TNL::NetConnection::getInitialRecvSequence ( ) [inline]

Returns the initial sequence number of packets sent from the remote host.

U32 TNL::NetConnection::getInitialSendSequence ( ) [inline]

Returns the initial sequence number of packets sent to the remote host.

void TNL::NetConnection::connect ( NetInterface * connectionInterface,

const Address & address,

bool requestKeyExchange = false,

bool requestCertificate = false

)

Connect to a server through a given network interface.
The connection request can require that the connection use encryption, or that the remote host's certificate be validated by a known Certificate Authority

bool TNL::NetConnection::connectLocal ( NetInterface * connectionInterface,

NetInterface * localServerInterface

)

Connects to a server interface within the same process.

void TNL::NetConnection::connectArranged ( NetInterface * connectionInterface,

const Vector< Address > & possibleAddresses,

Nonce & myNonce,

Nonce & remoteNonce,

ByteBufferPtr sharedSecret,

bool isInitiator,

bool requestsKeyExchange = false,

bool requestsCertificate = false

)

Connects to a remote host that is also connecting to this connection (negotiated by a third party).

void TNL::NetConnection::disconnect ( const char * reason )

Sends a disconnect packet to notify the remote host that this side is terminating the connection for the specified reason.
This will remove the connection from its NetInterface, and may have the side effect that the connection is deleted, if there are no other objects with RefPtrs to the connection.

bool TNL::NetConnection::windowFull ( )

Returns true if the packet send window is full and no more data packets can be sent.

void TNL::NetConnection::computeNegotiatedRate ( ) [private]

Called internally when the local or remote rate changes.

PacketNotify* TNL::NetConnection::getCurrentWritePacketNotify ( ) [inline, protected]

Returns the notify structure for the current packet write, or last written packet.

ConnectionParameters& TNL::NetConnection::getConnectionParameters ( ) [inline]

bool TNL::NetConnection::isInitiator ( ) [inline]

returns true if this object initiated the connection with the remote host

void TNL::NetConnection::setRemoteConnectionObject ( NetConnection * connection ) [inline]

NetConnection* TNL::NetConnection::getRemoteConnectionObject ( ) [inline]

char* TNL::NetConnection::getErrorBuffer ( ) [inline, static]

returns the current error buffer

void TNL::NetConnection::setLastError ( const char * fmt,

...

) [static]

Sets an error string and notifies the currently processing connection that it should terminate.

void TNL::NetConnection::setInterface ( NetInterface * myInterface )

Sets the NetInterface this NetConnection will communicate through.

NetInterface* TNL::NetConnection::getInterface ( )

Returns the NetInterface this connection communicates through.

void TNL::NetConnection::setSymmetricCipher ( SymmetricCipher * theCipher )

Sets the SymmetricCipher this NetConnection will use for encryption.

virtual NetClassGroup TNL::NetConnection::getNetClassGroup ( ) const [inline, virtual]

Returns the class group of objects that can be transmitted over this NetConnection.

void TNL::NetConnection::setPingTimeouts ( U32 msPerPing,

U32 pingRetryCount

) [inline]

Sets the ping/timeout characteristics for a fixed-rate connection. Total timeout is msPerPing * pingRetryCount.

void TNL::NetConnection::setSimulatedNetParams ( F32 packetLoss,

U32 latency

) [inline]

Simulates a network situation with a percentage random packet loss and a connection one way latency as specified.

void TNL::NetConnection::setIsConnectionToServer ( ) [inline]

Specifies that this NetConnection instance is a connection to a "server.".

bool TNL::NetConnection::isConnectionToServer ( ) [inline]

Returns true if this is a connection to a "server.".

void TNL::NetConnection::setIsConnectionToClient ( ) [inline]

Specifies that this NetConnection instance is a connection to a "client.".

bool TNL::NetConnection::isConnectionToClient ( ) [inline]

Returns true if this is a connection to a "client.".

bool TNL::NetConnection::isLocalConnection ( ) [inline]

Returns true if the remote side of this connection is a NetConnection instance in on the same host.

bool TNL::NetConnection::isNetworkConnection ( ) [inline]

Returns true if the remote side if this connection is on a remote host.

F32 TNL::NetConnection::getRoundTripTime ( ) [inline]

Returns the running average packet round trip time.

F32 TNL::NetConnection::getOneWayTime ( ) [inline]

Returns have of the average of the round trip packet time.

const Address& TNL::NetConnection::getNetAddress ( )

Returns the remote address of the host we're connected or trying to connect to.

const char* TNL::NetConnection::getNetAddressString ( ) const [inline]

Returns the remote address in string form.

void TNL::NetConnection::setNetAddress ( const Address & address )

Sets the address of the remote host we want to connect to.

NetError TNL::NetConnection::sendPacket ( BitStream * stream )

Sends a packet that was written into a BitStream to the remote host, or the mRemoteConnection on this host.

bool TNL::NetConnection::checkTimeout ( U32 time )

Checks to see if the connection has timed out, possibly sending a ping packet to the remote host. Returns true if the connection timed out.

void TNL::NetConnection::checkPacketSend ( bool force,

U32 currentTime

)

Checks to see if a packet should be sent at the currentTime to the remote host.
If force is true and there is space in the window, it will always send a packet.

void TNL::NetConnection::setConnectionState ( NetConnectionState state ) [inline]

Sets the current connection state of this NetConnection.

NetConnectionState TNL::NetConnection::getConnectionState ( ) [inline]

Gets the current connection state of this NetConnection.

bool TNL::NetConnection::isEstablished ( ) [inline]

Returns true if the connection handshaking has completed successfully.

void TNL::NetConnection::setIsAdaptive ( )

Enables the adaptive protocol.
By default NetConnection operates with a fixed rate protocol - that is, it sends a packet every few milliseconds, based on some configuration parameters. However, it is possible to use an adaptive rate protocol that attempts to maximize thoroughput over the connection.
Calling this function enables this behavior.

void TNL::NetConnection::setFixedRateParameters ( U32 minPacketSendPeriod,

U32 minPacketRecvPeriod,

U32 maxSendBandwidth,

U32 maxRecvBandwidth

)

sets the fixed rate send and receive data sizes, and sets the connection to not behave as an adaptive rate connection

bool TNL::NetConnection::isAdaptive ( ) [inline]

Query the adaptive status of the connection.

virtual bool TNL::NetConnection::isDataToTransmit ( ) [inline, virtual]

Returns true if this connection has data to transmit.
The adaptive rate protocol needs to be able to tell if there is data ready to be sent, so that it can avoid sending unnecessary packets. Each subclass of NetConnection may need to send different data - events, ghost updates, or other things. Therefore, this hook is provided so that child classes can overload it and let the adaptive protocol function properly.

Note:
Make sure this calls to its parents - the accepted idiom is:
return Parent::isDataToTransmit() || localConditions();

Reimplemented in TNL::EventConnection, TNL::GhostConnection, and TNLTest::TestConnection.

void TNL::NetConnection::setTranslatesStrings ( )

Enables string tag translation on this connection.

Friends And Related Function Documentation

friend class NetInterface [friend]

friend class ConnectionStringTable [friend]

Field Documentation

U32 TNL::NetConnection::mLastPacketRecvTime [private]

Time of the receipt of the last data packet.

U32 TNL::NetConnection::mLastSeqRecvdAtSend[MaxPacketWindowSize] [private]

The sequence number of the last packet received from the remote host when we sent the packet with sequence X & PacketWindowMask.

U32 TNL::NetConnection::mLastSeqRecvd [private]

The sequence number of the most recently received packet from the remote host.

U32 TNL::NetConnection::mHighestAckedSeq [private]

The highest sequence number the remote side has acknowledged.

U32 TNL::NetConnection::mLastSendSeq [private]

The sequence number of the last packet sent.

U32 TNL::NetConnection::mAckMask[MaxAckMaskSize] [private]

long string of bits, each acking a packet sent by the remote host
The bit associated with mLastSeqRecvd is the low bit of the 0'th word of mAckMask.

U32 TNL::NetConnection::mLastRecvAckAck [private]

The highest sequence this side knows the other side has received an ACK or NACK for.

U32 TNL::NetConnection::mInitialSendSeq [private]

The first mLastSendSeq for this side of the connection.

U32 TNL::NetConnection::mInitialRecvSeq [private]

The first mLastSeqRecvd (the first mLastSendSeq for the remote host).

U32 TNL::NetConnection::mHighestAckedSendTime [private]

The send time of the highest packet sequence acked by the remote host.
Used in the computation of round trip time.

U32 TNL::NetConnection::mPingTimeout [private]

Milliseconds to wait before sending a ping packet.

U32 TNL::NetConnection::mPingRetryCount [private]

Number of unacknowledged pings to send before timing out.

BitSet32 TNL::NetConnection::mTypeFlags [private]

Flags describing the type of connection this is, OR'd from NetConnectionTypeFlags.

U32 TNL::NetConnection::mLastUpdateTime [private]

The last time a packet was sent from this instance.

F32 TNL::NetConnection::mRoundTripTime [private]

Running average round trip time.

U32 TNL::NetConnection::mSendDelayCredit [private]

Metric to help compensate for irregularities on fixed rate packet sends.

U32 TNL::NetConnection::mSimulatedLatency [private]

Amount of additional time this connection delays its packet sends to simulate latency in the connection.

F32 TNL::NetConnection::mSimulatedPacketLoss [private]

Function to simulate packet loss on a network.

NetRate TNL::NetConnection::mLocalRate [private]

Current communications rate negotiated for this connection.

NetRate TNL::NetConnection::mRemoteRate [private]

Maximum allowable communications rate for this connection.

bool TNL::NetConnection::mLocalRateChanged [private]

Set to true when the local connection's rate has changed.

U32 TNL::NetConnection::mCurrentPacketSendSize [private]

Current size of each packet sent to the remote host.

U32 TNL::NetConnection::mCurrentPacketSendPeriod [private]

Millisecond delay between sent packets.

Address TNL::NetConnection::mNetAddress [private]

The network address of the host this instance is connected to.

U32 TNL::NetConnection::mPingSendCount [private]

Number of unacknowledged ping packets sent to the remote host.

U32 TNL::NetConnection::mLastPingSendTime [private]

Last time a ping packet was sent from this connection.

PacketNotify* TNL::NetConnection::mNotifyQueueHead [protected]

Linked list of structures representing the data in sent packets.

PacketNotify* TNL::NetConnection::mNotifyQueueTail [protected]

Tail of the notify queue linked list. New packets are added to the end of the tail.

SafePtr<NetConnection> TNL::NetConnection::mRemoteConnection [protected]

Safe pointer to a short-circuit remote connection on the same host.
This currently isn't enabled - see the end of netConnection.cpp for an example of how to use this. If it's set, the code will use short circuited networking.

ConnectionParameters TNL::NetConnection::mConnectionParameters [protected]

U32 TNL::NetConnection::mConnectSendCount

Number of challenge or connect requests sent to the remote host.

U32 TNL::NetConnection::mConnectLastSendTime

The send time of the last challenge or connect request.

char TNL::NetConnection::mErrorBuffer[256] [static, protected]

String buffer that errors are written into.

SafePtr<NetInterface> TNL::NetConnection::mInterface [protected]

The NetInterface of which this NetConnection is a member.

RefPtr<SymmetricCipher> TNL::NetConnection::mSymmetricCipher [protected]

The helper object that performs symmetric encryption on packets.

NetConnectionState TNL::NetConnection::mConnectionState

Current state of this NetConnection.

F32 TNL::NetConnection::cwnd [private]

F32 TNL::NetConnection::ssthresh [private]

U32 TNL::NetConnection::mLastSeqRecvdAck [private]

U32 TNL::NetConnection::mLastAckTime [private]

ConnectionStringTable* TNL::NetConnection::mStringTable [private]

Helper for managing translation between global NetStringTable ids to local ids for this connection.


Adaptive Protocol
Functions and state for the adaptive rate protocol. TNL's adaptive rate uses rate control algorithms similar to TCP/IP's. There are a few state variables here that aren't documented.
void	setIsAdaptive ()
	Enables the adaptive protocol.
void	setFixedRateParameters (U32 minPacketSendPeriod, U32 minPacketRecvPeriod, U32 maxSendBandwidth, U32 maxRecvBandwidth)
	sets the fixed rate send and receive data sizes, and sets the connection to not behave as an adaptive rate connection
bool	isAdaptive ()
	Query the adaptive status of the connection.
virtual bool	isDataToTransmit ()
	Returns true if this connection has data to transmit.
F32	cwnd
F32	ssthresh
U32	mLastSeqRecvdAck
U32	mLastAckTime
Public Types
enum	TerminationReason { ReasonTimedOut, ReasonFailedConnectHandshake, ReasonRemoteHostRejectedConnection, ReasonRemoteDisconnectPacket, ReasonDuplicateConnectionAttempt, ReasonSelfDisconnect, ReasonError }
enum	NetConnectionTypeFlags { ConnectionToServer = BIT(0), ConnectionToClient = BIT(1), ConnectionAdaptive = BIT(2), ConnectionRemoteAdaptive = BIT(3) }
	Flags specifying the type of the connection instance. More...
enum	NetConnectionState { NotConnected = 0, AwaitingChallengeResponse, SendingPunchPackets, ComputingPuzzleSolution, AwaitingConnectResponse, ConnectTimedOut, ConnectRejected, Connected, Disconnected, TimedOut, StateCount }
	Connection state flags for a NetConnection instance. More...
Public Member Functions
	NetConnection ()
	~NetConnection ()
U32	getNextSendSequence ()
	Returns the next send sequence that will be sent by this side.
U32	getLastSendSequence ()
	Returns the sequence of the last packet sent by this connection, or the current packet's send sequence if called from within writePacket().
void	setInitialRecvSequence (U32 sequence)
	Sets the initial sequence number of packets read from the remote host.
U32	getInitialRecvSequence ()
	Returns the initial sequence number of packets sent from the remote host.
U32	getInitialSendSequence ()
	Returns the initial sequence number of packets sent to the remote host.
void	connect (NetInterface *connectionInterface, const Address &address, bool requestKeyExchange=false, bool requestCertificate=false)
	Connect to a server through a given network interface.
bool	connectLocal (NetInterface connectionInterface, NetInterface localServerInterface)
	Connects to a server interface within the same process.
void	connectArranged (NetInterface *connectionInterface, const Vector< Address > &possibleAddresses, Nonce &myNonce, Nonce &remoteNonce, ByteBufferPtr sharedSecret, bool isInitiator, bool requestsKeyExchange=false, bool requestsCertificate=false)
	Connects to a remote host that is also connecting to this connection (negotiated by a third party).
void	disconnect (const char *reason)
	Sends a disconnect packet to notify the remote host that this side is terminating the connection for the specified reason.
bool	windowFull ()
	Returns true if the packet send window is full and no more data packets can be sent.
ConnectionParameters &	getConnectionParameters ()
bool	isInitiator ()
	returns true if this object initiated the connection with the remote host
void	setRemoteConnectionObject (NetConnection *connection)
NetConnection *	getRemoteConnectionObject ()
void	setInterface (NetInterface *myInterface)
	Sets the NetInterface this NetConnection will communicate through.
NetInterface *	getInterface ()
	Returns the NetInterface this connection communicates through.
void	setSymmetricCipher (SymmetricCipher *theCipher)
	Sets the SymmetricCipher this NetConnection will use for encryption.
virtual NetClassGroup	getNetClassGroup () const
	Returns the class group of objects that can be transmitted over this NetConnection.
void	setPingTimeouts (U32 msPerPing, U32 pingRetryCount)
	Sets the ping/timeout characteristics for a fixed-rate connection. Total timeout is msPerPing * pingRetryCount.
void	setSimulatedNetParams (F32 packetLoss, U32 latency)
	Simulates a network situation with a percentage random packet loss and a connection one way latency as specified.
void	setIsConnectionToServer ()
	Specifies that this NetConnection instance is a connection to a "server.".
bool	isConnectionToServer ()
	Returns true if this is a connection to a "server.".
void	setIsConnectionToClient ()
	Specifies that this NetConnection instance is a connection to a "client.".
bool	isConnectionToClient ()
	Returns true if this is a connection to a "client.".
bool	isLocalConnection ()
	Returns true if the remote side of this connection is a NetConnection instance in on the same host.
bool	isNetworkConnection ()
	Returns true if the remote side if this connection is on a remote host.
F32	getRoundTripTime ()
	Returns the running average packet round trip time.
F32	getOneWayTime ()
	Returns have of the average of the round trip packet time.
const Address &	getNetAddress ()
	Returns the remote address of the host we're connected or trying to connect to.
const char *	getNetAddressString () const
	Returns the remote address in string form.
void	setNetAddress (const Address &address)
	Sets the address of the remote host we want to connect to.
NetError	sendPacket (BitStream *stream)
	Sends a packet that was written into a BitStream to the remote host, or the mRemoteConnection on this host.
bool	checkTimeout (U32 time)
	Checks to see if the connection has timed out, possibly sending a ping packet to the remote host. Returns true if the connection timed out.
void	checkPacketSend (bool force, U32 currentTime)
	Checks to see if a packet should be sent at the currentTime to the remote host.
void	setConnectionState (NetConnectionState state)
	Sets the current connection state of this NetConnection.
NetConnectionState	getConnectionState ()
	Gets the current connection state of this NetConnection.
bool	isEstablished ()
	Returns true if the connection handshaking has completed successfully.
void	setTranslatesStrings ()
	Enables string tag translation on this connection.
Static Public Member Functions
char *	getErrorBuffer ()
	returns the current error buffer
void	setLastError (const char *fmt,...)
	Sets an error string and notifies the currently processing connection that it should terminate.
Data Fields
U32	mConnectSendCount
	Number of challenge or connect requests sent to the remote host.
U32	mConnectLastSendTime
	The send time of the last challenge or connect request.
NetConnectionState	mConnectionState
	Current state of this NetConnection.
Protected Member Functions
virtual void	onConnectTerminated (TerminationReason reason, const char *rejectionString)
	Called when a pending connection is terminated.
virtual void	onConnectionTerminated (TerminationReason, const char *errorDisconnectString)
	Called when this established connection is terminated for any reason.
virtual void	onConnectionEstablished ()
	Called when the connection is successfully established with the remote host.
virtual bool	validateCertficate (Certificate *theCertificate, bool isInitiator)
	validates that the given certificate is a valid certificate for this connection.
virtual bool	validatePublicKey (AsymmetricKey *theKey, bool isInitiator)
	Validates that the given public key is valid for this connection.
virtual void	writeConnectRequest (BitStream *stream)
	Fills the connect request packet with additional custom data (from a subclass).
virtual bool	readConnectRequest (BitStream stream, const char *errorString)
	Called after this connection instance is created on a non-initiating host (server).
virtual void	writeConnectAccept (BitStream *stream)
	Writes any data needed to start the connection on the accept packet.
virtual bool	readConnectAccept (BitStream stream, const char *errorString)
	Reads out the extra data read by writeConnectAccept and returns true if it is processed properly.
virtual void	readPacket (BitStream *bstream)
	Called to read a subclass's packet data from the packet.
virtual void	prepareWritePacket ()
	Called to prepare the connection for packet writing.
virtual void	writePacket (BitStream bstream, PacketNotify note)
	Called to write a subclass's packet data into the packet.
virtual void	packetReceived (PacketNotify *note)
	Called when the packet associated with the specified notify is known to have been received by the remote host.
virtual void	packetDropped (PacketNotify *note)
	Called when the packet associated with the specified notify is known to have been not received by the remote host.
virtual PacketNotify *	allocNotify ()
	Allocates a data record to track data sent on an individual packet.
void	readRawPacket (BitStream *bstream)
	Reads a raw packet from a BitStream, as dispatched from NetInterface.
void	writeRawPacket (BitStream *bstream, NetPacketType packetType)
	Writes a full packet of the specified type into the BitStream.
void	writePacketHeader (BitStream *bstream, NetPacketType packetType)
	Writes the notify protocol's packet header into the BitStream.
bool	readPacketHeader (BitStream *bstream)
	Reads a notify protocol packet header from the BitStream and returns true if it was a data packet that needs more processing.
void	writePacketRateInfo (BitStream bstream, PacketNotify note)
	Writes any packet send rate change information into the packet.
void	readPacketRateInfo (BitStream *bstream)
	Reads any packet send rate information requests from the packet.
void	sendPingPacket ()
	Sends a ping packet to the remote host, to determine if it is still alive and what its packet window status is.
void	sendAckPacket ()
	Sends an ack packet to the remote host, in response to receiving a ping packet.
void	handleNotify (U32 sequence, bool recvd)
	Dispatches a notify when a packet is ACK'd or NACK'd.
void	keepAlive ()
	Called when a packet is received to stop any timeout action in progress.
void	clearAllPacketNotifies ()
	Clears out the pending notify list.
PacketNotify *	getCurrentWritePacketNotify ()
	Returns the notify structure for the current packet write, or last written packet.
Protected Attributes
PacketNotify *	mNotifyQueueHead
	Linked list of structures representing the data in sent packets.
PacketNotify *	mNotifyQueueTail
	Tail of the notify queue linked list. New packets are added to the end of the tail.
SafePtr< NetConnection >	mRemoteConnection
	Safe pointer to a short-circuit remote connection on the same host.
ConnectionParameters	mConnectionParameters
SafePtr< NetInterface >	mInterface
	The NetInterface of which this NetConnection is a member.
RefPtr< SymmetricCipher >	mSymmetricCipher
	The helper object that performs symmetric encryption on packets.
Static Protected Attributes
char	mErrorBuffer [256]
	String buffer that errors are written into.
Private Types
typedef Object	Parent
enum	HeaderConstants { MaxPacketWindowSizeShift = 5, MaxPacketWindowSize = (1 << MaxPacketWindowSizeShift), PacketWindowMask = MaxPacketWindowSize - 1, MaxAckMaskSize = 1 << (MaxPacketWindowSizeShift - 5), MaxAckByteCount = MaxAckMaskSize << 2, SequenceNumberBitSize = 11, SequenceNumberWindowSize = (1 << SequenceNumberBitSize), SequenceNumberMask = -SequenceNumberWindowSize, AckSequenceNumberBitSize = 10, AckSequenceNumberWindowSize = (1 << AckSequenceNumberBitSize), AckSequenceNumberMask = -AckSequenceNumberWindowSize, PacketHeaderBitSize = 3 + AckSequenceNumberBitSize + SequenceNumberBitSize, PacketHeaderByteSize = (PacketHeaderBitSize + 7) >> 3, PacketHeaderPadBits = (PacketHeaderByteSize << 3) - PacketHeaderBitSize, MessageSignatureBytes = 5 }
	Constants controlling the data representation of each packet header. More...
enum	NetPacketType { DataPacket, PingPacket, AckPacket, InvalidPacketType }
	Two-bit identifier for each connected packet. More...
enum	DefaultPingConstants { AdaptiveInitialPingTimeout = 60000, AdaptivePingRetryCount = 4, DefaultPingTimeout = 5000, DefaultPingRetryCount = 10, AdaptiveUnackedSentPingTimeout = 3000 }
	Constants controlling the behavior of pings and timeouts. More...
enum	RateDefaults { DefaultFixedBandwidth = 2500, DefaultFixedSendPeriod = 96, MaxFixedBandwidth = 65535, MaxFixedSendPeriod = 2047 }
Private Member Functions
bool	hasUnackedSentPackets ()
	Returns true if this connection has sent packets that have not yet been acked by the remote host.
void	computeNegotiatedRate ()
	Called internally when the local or remote rate changes.
Private Attributes
U32	mLastPacketRecvTime
	Time of the receipt of the last data packet.
U32	mLastSeqRecvdAtSend [MaxPacketWindowSize]
	The sequence number of the last packet received from the remote host when we sent the packet with sequence X & PacketWindowMask.
U32	mLastSeqRecvd
	The sequence number of the most recently received packet from the remote host.
U32	mHighestAckedSeq
	The highest sequence number the remote side has acknowledged.
U32	mLastSendSeq
	The sequence number of the last packet sent.
U32	mAckMask [MaxAckMaskSize]
	long string of bits, each acking a packet sent by the remote host
U32	mLastRecvAckAck
	The highest sequence this side knows the other side has received an ACK or NACK for.
U32	mInitialSendSeq
	The first mLastSendSeq for this side of the connection.
U32	mInitialRecvSeq
	The first mLastSeqRecvd (the first mLastSendSeq for the remote host).
U32	mHighestAckedSendTime
	The send time of the highest packet sequence acked by the remote host.
U32	mPingTimeout
	Milliseconds to wait before sending a ping packet.
U32	mPingRetryCount
	Number of unacknowledged pings to send before timing out.
BitSet32	mTypeFlags
	Flags describing the type of connection this is, OR'd from NetConnectionTypeFlags.
U32	mLastUpdateTime
	The last time a packet was sent from this instance.
F32	mRoundTripTime
	Running average round trip time.
U32	mSendDelayCredit
	Metric to help compensate for irregularities on fixed rate packet sends.
U32	mSimulatedLatency
	Amount of additional time this connection delays its packet sends to simulate latency in the connection.
F32	mSimulatedPacketLoss
	Function to simulate packet loss on a network.
NetRate	mLocalRate
	Current communications rate negotiated for this connection.
NetRate	mRemoteRate
	Maximum allowable communications rate for this connection.
bool	mLocalRateChanged
	Set to true when the local connection's rate has changed.
U32	mCurrentPacketSendSize
	Current size of each packet sent to the remote host.
U32	mCurrentPacketSendPeriod
	Millisecond delay between sent packets.
Address	mNetAddress
	The network address of the host this instance is connected to.
U32	mPingSendCount
	Number of unacknowledged ping packets sent to the remote host.
U32	mLastPingSendTime
	Last time a ping packet was sent from this connection.
ConnectionStringTable *	mStringTable
	Helper for managing translation between global NetStringTable ids to local ids for this connection.
Friends
class	NetInterface
class	ConnectionStringTable