Connection Class Reference

Class that represents a network connection. More...

#include <connection.h>

Inheritance diagram for Connection:

Collaboration diagram for Connection:

Classes
class	ConnectionObserver
	Interface for receiving network traffic. More...

Public Types
enum	ConnectionState { Initial, Open, Closing, Error }

Public Slots
void	socketReady ()
void	run ()
void	encryptedBytesWritten (qint64 written)
void	sslErrors (const QList< QSslError > &errors)
void	socketError (QAbstractSocket::SocketError socketError)
void	disconnected ()
void	readyRead ()

Signals
void	error (QTcpSocket::SocketError socketError)
void	finished ()
void	blackListNetworkAddr (QHostAddress aAddr)
void	connectionAttemptFailed (const Hash &aNodeHash)

Public Member Functions
	Connection (int aSocketDescriptor, ConnectionObserver &aObserver, Model &aModel, MController &aController)
	Connection (const QHostAddress &aAddr, const int aPort, ConnectionObserver &aObserver, Model &aModel, MController &aController, const Hash &aFpOfNodeToTry)
	~Connection ()
Node *	node () const
void	setNode (Node *aNode)
QHostAddress	peerAddress () const
const Hash &	fingerPrintOfNodeAttempted ()
ConnectionState	connectionState () const
ProtocolItemType	stageOfBucketFill () const
void	setStageOfBucketFill (ProtocolItemType aStage)
bool	isInbound () const
time_t	getOpenTime () const
Hash	getPeerHash () const
unsigned long	bytesIn () const
unsigned long	bytesOut () const
bool	forciblyCloseSocket ()
bool	isInPrivateAddrSpace () const

Static Public Member Functions
static bool	Ipv6AddressesEqual (const Q_IPV6ADDR &aAddr1, const Q_IPV6ADDR &aAddr2)

Public Attributes
QList< SendQueueItem >	iSendQueue
QList< QByteArray * >	iNextProtocolItemToSend
bool	iNeedsToRun
time_t	iTimeOfLastActivity
unsigned	iNumberOfPacketsReceived

Static Public Attributes
static const unsigned	iMinutesBetweenBucketFill = 30

Protected Member Functions
void	performRead ()
void	readLoop ()
void	runForIncomingConnections ()
void	runForOutgoingConnections ()
void	checkForBucketFill ()
void	flushSocket ()
void	setupSocketSignals ()
void	msleep (int aMilliSeconds)

Protected Attributes
ConnectionState	iConnectionState
ConnectionObserver &	iObserver
QSslSocket *	iSocket
Model &	iModel
quint32	iBytesExpectedInPacketBeingRead
QByteArray *	iBytesRead
int	iInvocationsSinceLastByteReceived
Node *	iNodeOfConnectedPeer
QHostAddress	iAddrToConnect
const int	iPortToConnect
const int	iSocketDescriptor
const bool	iSocketIsIncoming
MController &	iController
Hash	iFpOfNodeWeTrying
ProtocolItemType	iStageOfBucketFill
quint32	iTimeOfBucketFill
Hash	iEndOfBucket
const time_t	iSocketOpenTime
unsigned long	iBytesIn
unsigned long	iBytesOut
QHostAddress	iPeerAddress
int	iBytesPendingWrite
int	iSleepBetweenSendOperations
Hash	iPeerHash

Detailed Description

Class that represents a network connection.

At runtime we'll have 1-n of these. This is a base-class that allows us to do some operations like "send", "receive" without needing to know if we're having a socket conn or some other kind.

Member Enumeration Documentation

enum Connection::ConnectionState

Enumeration of the connection states

Enumerator
Initial	SYN packet sent
Open	SSL handshake was success, peerCert is avail
Closing	Disconnection has been asked
Error	Connection itself reports an error

Constructor & Destructor Documentation

Connection::Connection	(	int	aSocketDescriptor,
		ConnectionObserver &	aObserver,
		Model &	aModel,
		MController &	aController
	)

Constructor to use when incoming connection

Connection::Connection	(	const QHostAddress &	aAddr,
		const int	aPort,
		ConnectionObserver &	aObserver,
		Model &	aModel,
		MController &	aController,
		const Hash &	aFpOfNodeToTry
	)

Constructor. Class will initiate connetion to given addr.

Parameters

aAddr	network address to try
aPort	port in said addr
aObserver	class wishing to receive status updates about this connection
aModel	datamodel reference
aController	application controller reference
aFpOfNodeToTry	sometimes we need to connect some particular node ; hash of the attempted host may be given here. It is not used by connection itself but the observers may query it in case of failed connection of the connection was attempted to some particular node. In particular this logic is used by publishing engine that needs to know not only successful connections but also failed ones and for failed ones we don't get node FP via normal mechanism (node greeting)

Connection::~Connection

(

)

Method for tearing down a connection

Member Function Documentation

void Connection::blackListNetworkAddr ( QHostAddress  aAddr )

signal

unsigned long Connection::bytesIn ( ) const

inline

returs data transfer amount

unsigned long Connection::bytesOut ( ) const

inline

returns data transfer amount

void Connection::checkForBucketFill ( )

protected

method for keeping buckets filled. this checks if we have content that according to its network addr should belong to that peer ; and then adds it to send queue

void Connection::connectionAttemptFailed ( const Hash &  aNodeHash )

signal

Emitted when outgoing connectio fails. Used for keeping count on nodes not to try immediately again

ConnectionState Connection::connectionState ( ) const

inline

getter method for connection state

void Connection::disconnected ( )

slot

Connected from QSslSocket. Called on close

void Connection::encryptedBytesWritten ( qint64  written )

slot

Connected from QSslSocket. Called when bytes have been written

void Connection::error ( QTcpSocket::SocketError  socketError )

signal

const Hash& Connection::fingerPrintOfNodeAttempted

(

)

method for getting the hash this connection was trying to attempt .. if connection was originally asked to be to some particular node, this will return hash of the node ; if connection was to no particular node, a zero hash will be returned

void Connection::finished ( )

signal

void Connection::flushSocket ( )

protected

method that tries to flush pending output, if platform supports

bool Connection::forciblyCloseSocket

(

)

Forcibly closes socket.

Returns

true if socket was still allocated and its "abort" method got called.

time_t Connection::getOpenTime ( ) const

inline

method for getting open time of connection

Hash Connection::getPeerHash

(

)

const

method for getting peering node fingerprint. if connection is not yet open, returns KNullHash

static bool Connection::Ipv6AddressesEqual ( const Q_IPV6ADDR &  aAddr1, const Q_IPV6ADDR &  aAddr2  )

static

helper method for comparing ipv6 addresses

bool Connection::isInbound ( ) const

inline

method for getting information if connection is inbound

bool Connection::isInPrivateAddrSpace

(

)

const

method for checking if connection is in private (non-routable) ipv4-addr space like 192.168.. network

void Connection::msleep ( int  aMilliSeconds )

protected

stops execution for some time

Node* Connection::node ( ) const

inline

getter method for node of this connection. value may be null if connection is still in early stage so non-nulliness must be tested

Parameters

none

Returns

node of connection or NULL if handshake still pending. ownership is NOT transferred, it is not ok to delete the returned pointer.

QHostAddress Connection::peerAddress

(

)

const

method for getting peer addr

void Connection::performRead ( )

protected

void Connection::readLoop ( )

protected

called from run()

void Connection::readyRead ( )

slot

Connected from QSslSocket. Called when bytes are available

void Connection::run ( )

slot

this class is a kind of a thread, we need to have run ; note that right now QThread is not inherited but our worker-method is still named run, called by thread when it is started ( from networklistener or networkconnectorengine)

void Connection::runForIncomingConnections ( )

protected

2 versions of run, called from run(),first for incoming connections

void Connection::runForOutgoingConnections ( )

protected

2 versions of run, called from run(),then for outgoing connections

void Connection::setNode ( Node *  aNode )

inline

for testing purposes only: this should never be called in production setup. this does get called from test-code

void Connection::setStageOfBucketFill ( ProtocolItemType  aStage )

inline

Method for setting bucket fill stage. See also stageOfBucketFill.

void Connection::setupSocketSignals ( )

protected

method that sets up signals/slots of socket

void Connection::socketError ( QAbstractSocket::SocketError  socketError )

slot

Connected from QSslSocket::error. Called on error

void Connection::socketReady ( )

slot

Called when socket is encrypted and ready to transmit

void Connection::sslErrors ( const QList< QSslError > &  errors )

slot

Connected from QSslSocket. Called on handshake errors

ProtocolItemType Connection::stageOfBucketFill ( ) const

inline

Method for getting the bucket fill stage. See explanation at documentation of the variable Connection::iStageOfBucketFill for idea how this should be used

Member Data Documentation

QHostAddress Connection::iAddrToConnect

protected

network address to connect, if connection is outgoing connection

quint32 Connection::iBytesExpectedInPacketBeingRead

protected

when starting to receive packet from peer, length is stored here

unsigned long Connection::iBytesIn

protected

transferred data amount

unsigned long Connection::iBytesOut

protected

transferred data amount

int Connection::iBytesPendingWrite

protected

indication if write operation has been started but is not yet complete

QByteArray* Connection::iBytesRead

protected

when reading packet from peer, this contains bytes being read

ConnectionState Connection::iConnectionState

protected

< closed/open etc.

MController& Connection::iController

protected

application controller reference

Hash Connection::iEndOfBucket

protected

Where our bucket ends. Our own node fp is the start of the bucket, here is the end

Hash Connection::iFpOfNodeWeTrying

protected

It may be that connection is asked to specific node, in addition to being into some known network address. If the node is known, store the target node fingerprintin here. This is used at least in wishlist-connections where the connection itself will signal its open-for-business state when connection to asked node is ready

int Connection::iInvocationsSinceLastByteReceived

protected

this variable here is used as counter during pending read of data packet, zeroed every time bytes are received ; if it reaches high number (a sign of stalled download) do drop connection to that peer

const unsigned Connection::iMinutesBetweenBucketFill = 30

static

how often peers are queried for new content to send/receive ; this is also max permitted lenght for data transmission inactivity ; nodes that have been idle longer than this are considered "dead"

Model& Connection::iModel

protected

datamodel reference

bool Connection::iNeedsToRun

if set to false, connection closes itself

QList<QByteArray *> Connection::iNextProtocolItemToSend

This is the next item to send. This does not include the length. .. as protocol items over socket are sent so that length goes first, as uint32, followed by that many bytes. This QByteArray contains the bytes, not the uint32 that goes first. Reason is that this is wanted this way is that the class doing the sending to be aware of the length, forcing this way it to calculate it itself.

Node* Connection::iNodeOfConnectedPeer

protected

node-data-structure of the connected node

unsigned Connection::iNumberOfPacketsReceived

nr of received complete protocol packets

ConnectionObserver& Connection::iObserver

protected

received data is sent to ConnectionObserver

QHostAddress Connection::iPeerAddress

protected

storage for peeraddress

Hash Connection::iPeerHash

protected

hash of peering node

const int Connection::iPortToConnect

protected

port to connect, if connection is outgoing connection

QList<SendQueueItem> Connection::iSendQueue

many things going on inside classified ads are about the connected node ; when node is disconnected, we may forget about many things that may have been in progress. therefore it may make sense to store also the queue of things to send in here ; when connection goes away, so goes the queue and no further processing needed.

The order of things in this list is significant, the first item to be append()ed should be sent first.

int Connection::iSleepBetweenSendOperations

protected

How many milliseconds to sleep between send operations

QSslSocket* Connection::iSocket

protected

socket for data transfer: the actual socket is owned by stack frame of the thread so even tough we have this pointer here, it may not be deleted

const int Connection::iSocketDescriptor

protected

descriptor of already-connected socket if connection is incoming-connection

const bool Connection::iSocketIsIncoming

protected

true if incoming socket

const time_t Connection::iSocketOpenTime

protected

time of socket open

ProtocolItemType Connection::iStageOfBucketFill

protected

method of handling around network churn is implemented in several places. .. churn requires us to copy stuff beloging to NodesAroundHash ( see nodemodel ) to nodes that are in the same bucket with us. Our concept of bucket is a bit stretched but there is kind of bucket and we will send of over new data to nodes that we think belongs to the bucket of connecting node.

sending the data happens in several stages, connection itself stores the stage here. filling the bucket according to stage then happens in NodeModel::getNextItemToSend method

quint32 Connection::iTimeOfBucketFill

protected

time of last bucket fill

time_t Connection::iTimeOfLastActivity

last time there was any traffic with peer

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The documentation for this class was generated from the following file:

• /tmp/classified-ads/classified_ads/net/connection.h