#include <HappyConnOpener.h>

Inheritance diagram for HappyConnOpener:

Collaboration diagram for HappyConnOpener:

[legend]

Classes
class	Attempt
	a connection opening attempt in progress (or falsy) More...

class	CbDialer
	AsyncCall dialer for our callback. Gives us access to callback Answer. More...

Public Types
typedef HappyConnOpenerAnswer	Answer

typedef CbcPointer< AsyncJob >	Pointer

Public Member Functions
	HappyConnOpener (const ResolvedPeersPointer &, const AsyncCall::Pointer &, HttpRequestPointer &, const time_t aFwdStart, int tries, const AccessLogEntryPointer &al)

virtual	~HappyConnOpener () override

void	allowPersistent (bool permitted)
	configures reuse of old connections More...

void	setRetriable (bool retriable)
	configures whether the request may be retried later if things go wrong More...

void	setHost (const char *)
	configures the origin server domain name More...

void	noteCandidatesChange ()
	reacts to changes in the destinations list More...

void	noteGavePrimeItsChance ()
	reacts to expired happy_eyeballs_connect_timeout More...

void	noteSpareAllowance ()
	reacts to satisfying happy_eyeballs_connect_gap and happy_eyeballs_connect_limit More...

bool	canBeCalled (AsyncCall &call) const
	whether we can be called More...

void	callStart (AsyncCall &call)

virtual void	callEnd ()
	called right after the called job method More...

virtual void	callException (const std::exception &e)
	called when the job throws during an async call More...

virtual void *	toCbdata ()=0

Static Public Member Functions
static Pointer	Start (AsyncJob *job)
	starts a freshly created job (i.e., makes the job asynchronous) More...

Public Attributes
HappyAbsoluteTime	primeStart = 0
	the start of the first connection attempt for the currentPeer More...

Protected Member Functions
void	deleteThis (const char *aReason)

void	mustStop (const char *aReason)

bool	done () const
	the job is destroyed in callEnd() when done() More...

Protected Attributes
const char *	stopReason
	reason for forcing done() to be true More...

const char *	typeName
	kid (leaf) class name, for debugging More...

AsyncCall::Pointer	inCall
	the asynchronous call being handled, if any More...

const InstanceId< AsyncJob >	id
	job identifier More...

Private Member Functions
	CBDATA_CHILD (HappyConnOpener)

virtual void	start () override
	called by AsyncStart; do not call directly More...

virtual bool	doneAll () const override
	whether positive goal has been reached More...

virtual void	swanSong () override

virtual const char *	status () const override
	internal cleanup; do not call directly More...

void	maybeOpenAnotherPrimeConnection ()
	starts a prime connection attempt if possible or does nothing otherwise More...

void	maybeGivePrimeItsChance ()

void	stopGivingPrimeItsChance ()
	called when the prime attempt has used up its chance for a solo victory More...

void	stopWaitingForSpareAllowance ()
	called when the spare attempt should no longer obey spare connection limits More...

void	maybeOpenSpareConnection ()
	if possible, starts a spare connection attempt More...

void	startConnecting (Attempt &, Comm::ConnectionPointer &)
	starts opening (or reusing) a connection to the given destination More...

void	openFreshConnection (Attempt &, Comm::ConnectionPointer &)

bool	reuseOldConnection (const Comm::ConnectionPointer &)

void	connectDone (const CommConnectCbParams &)

void	checkForNewConnection ()

void	updateSpareWaitAfterPrimeFailure ()
	reacts to a prime attempt failure More...

void	cancelSpareWait (const char *reason)
	stops waiting for the right conditions to open a spare connection More...

bool	ranOutOfTimeOrAttempts () const
	Check for maximum connection tries and forwarding time restrictions. More...

ErrorState *	makeError (const err_type type) const

Answer *	futureAnswer (const Comm::ConnectionPointer &)

void	sendSuccess (const Comm::ConnectionPointer &conn, bool reused, const char *connKind)
	send a successful result to the initiator (if it still needs an answer) More...

void	sendFailure ()
	inform the initiator about our failure to connect (if needed) More...

void	cancelAttempt (Attempt &, const char *reason)
	cancels the in-progress attempt, making its path a future candidate More...

Private Attributes
const time_t	fwdStart
	requestor start time More...

AsyncCall::Pointer	callback_
	handler to be called on connection completion. More...

ResolvedPeersPointer	destinations
	Candidate paths. Shared with the initiator. May not be finalized yet. More...

Attempt	prime
	current connection opening attempt on the prime track (if any) More...

Attempt	spare
	current connection opening attempt on the spare track (if any) More...

Comm::ConnectionPointer	currentPeer

HappySpareWait	spareWaiting
	preconditions for an attempt to open a spare connection More...

AccessLogEntryPointer	ale
	transaction details More...

ErrorState *	lastError = nullptr
	last problem details (or nil) More...

Comm::ConnectionPointer	lastFailedConnection
	nil if none has failed More...

bool	ignoreSpareRestrictions = false
	whether spare connection attempts disregard happy_eyeballs_* settings More...

bool	gotSpareAllowance = false
	whether we have received a permission to open a spare while spares are limited More...

bool	allowPconn_ = true
	whether persistent connections are allowed More...

bool	retriable_ = true
	whether we are opening connections for a request that may be resent More...

const char *	host_ = nullptr
	origin server domain name (or equivalent) More...

HttpRequestPointer	cause
	the request that needs a to-server connection More...

int	n_tries
	number of connection opening attempts, including those in the requestor More...

const char *	ranOutOfTimeOrAttemptsEarlier_ = nullptr
	Reason to ran out of time or attempts. More...

Friends
class	HappyOrderEnforcer

Detailed Description

A TCP connection opening algorithm based on Happy Eyeballs (RFC 8305). Maintains two concurrent connection opening tracks: prime and spare. Shares ResolvedPeers list with the job initiator.

Definition at line 102 of file HappyConnOpener.h.

Member Typedef Documentation

◆ Answer

typedef HappyConnOpenerAnswer HappyConnOpener::Answer

Definition at line 106 of file HappyConnOpener.h.

◆ Pointer

typedef CbcPointer<AsyncJob> AsyncJob::Pointer

inherited

Definition at line 34 of file AsyncJob.h.

Constructor & Destructor Documentation

◆ HappyConnOpener()

HappyConnOpener::HappyConnOpener	(	const ResolvedPeersPointer &	dests,
		const AsyncCall::Pointer &	aCall,
		HttpRequestPointer &	request,
		const time_t	aFwdStart,
		int	tries,
		const AccessLogEntryPointer &	al
	)

Definition at line 329 of file HappyConnOpener.cc.

References assert, callback_, destinations, and AsyncCall::getDialer().

◆ ~HappyConnOpener()

HappyConnOpener::~HappyConnOpener ( )

overridevirtual

Definition at line 342 of file HappyConnOpener.cc.

References host_, lastError, and safe_free.

Member Function Documentation

◆ allowPersistent()

void HappyConnOpener::allowPersistent ( bool permitted )

inline

Definition at line 135 of file HappyConnOpener.h.

References allowPconn_.

◆ callEnd()

void AsyncJob::callEnd ( )

virtualinherited

called right after the called job method

Reimplemented in Adaptation::Icap::Xaction.

Definition at line 136 of file AsyncJob.cc.

References AsyncCall::debugLevel, debugs, AsyncCall::debugSection, AsyncJob::done(), HERE(), AsyncJob::inCall, NULL, AsyncJob::status(), AsyncJob::swanSong(), and AsyncJob::typeName.

Referenced by Adaptation::Icap::Xaction::callEnd(), and AsyncJob::deleteThis().

◆ callException()

void AsyncJob::callException ( const std::exception & e )

virtualinherited

Reimplemented in ClientHttpRequest, Ftp::Server, Adaptation::Icap::ModXact, Adaptation::Icap::Xaction, Adaptation::Icap::ServiceRep, Ipc::Forwarder, and Ipc::Inquirer.

Definition at line 127 of file AsyncJob.cc.

References cbdataReferenceValid(), debugs, Must, AsyncJob::mustStop(), and CbdataParent::toCbdata().

Referenced by Ipc::Inquirer::callException(), Ipc::Forwarder::callException(), Ftp::Server::callException(), and Adaptation::Icap::Xaction::callException().

◆ callStart()

void AsyncJob::callStart ( AsyncCall & call )

inherited

called just before the called method

Definition at line 114 of file AsyncJob.cc.

References cbdataReferenceValid(), AsyncCall::debugLevel, debugs, AsyncCall::debugSection, AsyncJob::inCall, Must, AsyncJob::status(), CbdataParent::toCbdata(), and AsyncJob::typeName.

◆ canBeCalled()

bool AsyncJob::canBeCalled ( AsyncCall & call ) const

inherited

Definition at line 101 of file AsyncJob.cc.

References AsyncCall::cancel(), debugs, HERE(), AsyncJob::inCall, and NULL.

◆ cancelAttempt()

void HappyConnOpener::cancelAttempt	(	Attempt &	attempt,
		const char *	reason
	)

private

Definition at line 485 of file HappyConnOpener.cc.

References HappyConnOpener::Attempt::cancel(), destinations, Must, HappyConnOpener::Attempt::path, and ResolvedPeers::retryPath().

Referenced by swanSong().

◆ cancelSpareWait()

void HappyConnOpener::cancelSpareWait ( const char * reason )

private

Definition at line 662 of file HappyConnOpener.cc.

References HappySpareWait::clear(), debugs, HappySpareWait::forSpareAllowance, Must, spareWaiting, stopGivingPrimeItsChance(), stopWaitingForSpareAllowance(), and HappySpareWait::toGivePrimeItsChance.

Referenced by checkForNewConnection(), swanSong(), and updateSpareWaitAfterPrimeFailure().

◆ CBDATA_CHILD()

HappyConnOpener::CBDATA_CHILD ( HappyConnOpener )

private

◆ checkForNewConnection()

void HappyConnOpener::checkForNewConnection ( )

private

Called when an external event changes initiator interest, destinations, prime, spare, or spareWaiting. Leaves HappyConnOpener in one of these (mutually exclusive beyond the exceptional state #0) "stable" states:

0. Exceptional termination: done()

Processing a single peer: currentPeer 1.1. Connecting: prime || spare 1.2. Waiting for spare gap and/or paths: !prime && !spare
Waiting for a new peer: destinations->empty() && !destinations->destinationsFinalized && !currentPeer
Finished: destinations->empty() && destinations->destinationsFinalized && !currentPeer

Definition at line 687 of file HappyConnOpener.cc.

References cancelSpareWait(), current_dtime, currentPeer, debugs, destinations, ResolvedPeers::destinationsFinalized, AsyncJob::done(), doneAll(), ResolvedPeers::doneWithPeer(), ResolvedPeers::doneWithSpares(), ResolvedPeers::empty(), ResolvedPeers::extractFront(), HappySpareWait::forNewPeer, gotSpareAllowance, ignoreSpareRestrictions, maybeGivePrimeItsChance(), maybeOpenAnotherPrimeConnection(), maybeOpenSpareConnection(), Must, prime, primeStart, ranOutOfTimeOrAttempts(), spare, spareWaiting, and startConnecting().

Referenced by connectDone(), noteCandidatesChange(), noteGavePrimeItsChance(), and start().

◆ connectDone()

void HappyConnOpener::connectDone ( const CommConnectCbParams & params )

private

called by Comm::ConnOpener objects after a prime or spare connection attempt completes (successfully or not)

Definition at line 579 of file HappyConnOpener.cc.

References checkForNewConnection(), Comm::Connection::close(), CommCommonCbParams::conn, debugs, ERR_CONNECT_FAIL, HappyConnOpener::Attempt::finish(), CommCommonCbParams::flag, Comm::Connection::getPeer(), gotSpareAllowance, SpareAllowanceGiver::jobUsedAllowance(), lastError, lastFailedConnection, makeError(), Must, Comm::OK, HappyConnOpener::Attempt::path, peerConnectFailed(), prime, sendSuccess(), spare, spareWaiting, TheSpareAllowanceGiver, updateSpareWaitAfterPrimeFailure(), CommCommonCbParams::xerrno, and ErrorState::xerrno.

Referenced by openFreshConnection().

◆ deleteThis()

void AsyncJob::deleteThis ( const char * aReason )

protectedinherited

Definition at line 49 of file AsyncJob.cc.

References asyncCall(), AsyncJob::callEnd(), debugs, AsyncJob::inCall, JobMemFun(), Must, NULL, AsyncJob::stopReason, and AsyncJob::typeName.

Referenced by ConnStateData::connStateClosed().

◆ done()

bool AsyncJob::done ( ) const

protectedinherited

Definition at line 90 of file AsyncJob.cc.

References AsyncJob::doneAll(), NULL, and AsyncJob::stopReason.

Referenced by AsyncJob::callEnd(), checkForNewConnection(), and Downloader::downloadFinished().

◆ doneAll()

bool HappyConnOpener::doneAll ( ) const

overrideprivatevirtual

Reimplemented from AsyncJob.

Definition at line 364 of file HappyConnOpener.cc.

References callback_, AsyncCall::canceled(), destinations, ResolvedPeers::destinationsFinalized, ResolvedPeers::empty(), prime, ranOutOfTimeOrAttempts(), and spare.

Referenced by checkForNewConnection().

◆ futureAnswer()

HappyConnOpener::Answer * HappyConnOpener::futureAnswer ( const Comm::ConnectionPointer & conn )

private

Returns: pre-filled Answer if the initiator needs an answer (or nil)

Definition at line 458 of file HappyConnOpener.cc.

References assert, callback_, AsyncCall::canceled(), conn, AsyncCall::getDialer(), and n_tries.

Referenced by sendFailure(), and sendSuccess().

◆ makeError()

ErrorState * HappyConnOpener::makeError ( const err_type type ) const

private

Create "503 Service Unavailable" or "504 Gateway Timeout" error depending on whether this is a validation request. RFC 7234 section 5.2.2 says that we MUST reply with "504 Gateway Timeout" if validation fails and cached reply has proxy-revalidate, must-revalidate or s-maxage Cache-Control directive.

Definition at line 449 of file HappyConnOpener.cc.

References ale, cause, HttpRequest::flags, RefCount< C >::getRaw(), RequestFlags::needValidation, Http::scGatewayTimeout, Http::scServiceUnavailable, and type.

Referenced by connectDone(), and sendFailure().