Abstraction layer for TCP, UDP, TLS, UDS and filedescriptor sockets.

Classes
class	AcceptLimiter

class	CbEntry

class	Connection

class	ConnOpener

class	IoCallback
	Details about a particular Comm IO callback event. More...

class	TcpAcceptor

class	TcpKeepAlive
	Configuration settings for the TCP keep-alive feature. More...

Typedefs
typedef RefCount< Comm::Connection >	ConnectionPointer

Enumerations
enum	Flag { OK = 0 , COMM_ERROR = -1 , TIMEOUT = -4 , SHUTDOWN = -5 , IDLE = -6 , INPROGRESS = -7 , ERR_CONNECT = -8 , ERR_DNS = -9 , ERR_CLOSING = -10 , ERR_PROTOCOL = -11 , ENDFILE = -12 , ERR__END__ = -999999 }

enum	iocb_type { IOCB_NONE , IOCB_READ , IOCB_WRITE }
	Type of IO callbacks the Comm layer deals with. More...

Functions
std::ostream &	operator<< (std::ostream &, const Connection &)

std::ostream &	operator<< (std::ostream &os, const ConnectionPointer &conn)

bool	IsConnOpen (const Comm::ConnectionPointer &conn)

void	SetSelect (int, unsigned int, PF , void , time_t)
	Mark an FD to be watched for its IO status. More...

void	CallbackTableInit ()

void	CallbackTableDestruct ()

void	SelectLoopInit (void)
	Initialize the module on Squid startup. More...

void	ResetSelect (int fd)
	reset/undo/unregister the watch for an FD which was set by Comm::SetSelect() More...

Comm::Flag	DoSelect (int)
	Do poll and trigger callback functions as appropriate. More...

void	QuickPollRequired (void)

void	Read (const Comm::ConnectionPointer &conn, AsyncCall::Pointer &callback)

bool	MonitorsRead (int fd)
	whether the FD socket is being monitored for read More...

Comm::Flag	ReadNow (CommIoCbParams &params, SBuf &buf)

void	ReadCancel (int fd, AsyncCall::Pointer &callback)
	Cancel the read pending on FD. No action if none pending. More...

time_t	MortalReadTimeout (const time_t startTime, const time_t lifetimeLimit)
	maximum read delay for readers with limited lifetime More...

void	ApplyTcpKeepAlive (int fd, const TcpKeepAlive &)
	apply configured TCP keep-alive settings to the given FD socket More...

void	Write (const Comm::ConnectionPointer &conn, const char buf, int size, AsyncCall::Pointer &callback, FREE free_func)

void	Write (const Comm::ConnectionPointer &conn, MemBuf *mb, AsyncCall::Pointer &callback)

void	WriteCancel (const Comm::ConnectionPointer &conn, const char *reason)
	Cancel the write pending on FD. No action if none pending. More...

Variables
PF	HandleWrite

CbEntry *	iocb_table

PF	HandleRead
	callback handler to process an FD which is available for reading More...

Typedef Documentation

◆ ConnectionPointer

typedef RefCount<Comm::Connection> Comm::ConnectionPointer

Definition at line 28 of file forward.h.

Enumeration Type Documentation

◆ Flag

enum Comm::Flag

Enumerator
OK
COMM_ERROR
TIMEOUT
SHUTDOWN
IDLE
INPROGRESS
ERR_CONNECT
ERR_DNS
ERR_CLOSING
ERR_PROTOCOL
ENDFILE	read(2) returned success, but with 0 bytes
ERR__END__

Definition at line 15 of file Flag.h.

◆ iocb_type

enum Comm::iocb_type

Enumerator
IOCB_NONE
IOCB_READ
IOCB_WRITE

Definition at line 22 of file IoCallback.h.

Function Documentation

◆ ApplyTcpKeepAlive()

void Comm::ApplyTcpKeepAlive	(	int	fd,
		const TcpKeepAlive &	cfg
	)

Definition at line 51 of file Tcp.cc.

References Comm::TcpKeepAlive::enabled, Comm::TcpKeepAlive::idle, Comm::TcpKeepAlive::interval, SetBooleanSocketOption(), SetSocketOption(), and Comm::TcpKeepAlive::timeout.

Referenced by Comm::TcpAcceptor::acceptInto().

◆ CallbackTableDestruct()

void Comm::CallbackTableDestruct ( )

Definition at line 34 of file IoCallback.cc.

References Comm::IoCallback::conn, iocb_table, Comm::CbEntry::readcb, safe_free, Squid_MaxFD, and Comm::CbEntry::writecb.

Referenced by comm_exit().

◆ CallbackTableInit()

void Comm::CallbackTableInit ( )

Definition at line 22 of file IoCallback.cc.

References Comm::CbEntry::fd, IOCB_READ, iocb_table, IOCB_WRITE, Comm::CbEntry::readcb, Squid_MaxFD, Comm::IoCallback::type, Comm::CbEntry::writecb, and xcalloc().

Referenced by comm_init().

◆ DoSelect()

Comm::Flag Comm::DoSelect ( int msec )

Perform a select() or equivalent call. This is used by the main select loop engine to check for FD with IO available.

Check all connections for new connections and input data that is to be processed. Also check for connections with data queued and whether we can write it out.

Called to do the new-style IO, courtesy of of squid (like most of this new IO code). This routine handles the stuff we've hidden in comm_setselect and fd_table[] and calls callbacks for IO ready events.

Parameters

msec	milliseconds to poll for (limited by max_poll_time)

Check all connections for new connections and input data that is to be processed. Also check for connections with data queued and whether we can write it out.

Called to do the new-style IO, courtesy of of squid (like most of this new IO code). This routine handles the stuff we've hidden in comm_setselect and fd_table[] and calls callbacks for IO ready events.

Definition at line 311 of file ModDevPoll.cc.

References COMM_ERROR, comm_flush_updates(), COMM_SELECT_READ, COMM_SELECT_WRITE, StatHist::count(), DEBUG_DEVPOLL, debugs, devpoll_fd, devpoll_state, do_poll, dpoll_nfds, F(), fd_table, getCurrentTime(), ignoreErrno(), int, max_poll_time, NULL, OK, StatCounters::select_fds, StatCounters::select_fds_hist, StatCounters::select_loops, SetSelect(), statCounter, _devpoll_state::state, and TIMEOUT.

Referenced by CommSelectEngine::checkEvents().

◆ IsConnOpen()

bool Comm::IsConnOpen ( const Comm::ConnectionPointer & conn )

Definition at line 27 of file Connection.cc.

References conn.

◆ MonitorsRead()

bool Comm::MonitorsRead ( int fd )

Definition at line 29 of file Read.cc.

References assert, COMMIO_FD_READCB, and isOpen().

Referenced by HttpStateData::maybeReadVirginBody(), and fde::readPending().

◆ MortalReadTimeout()

time_t Comm::MortalReadTimeout	(	const time_t	startTime,
		const time_t	lifetimeLimit
	)

Definition at line 248 of file Read.cc.

References Config, min(), SquidConfig::read, squid_curtime, Ident::Timeout, and SquidConfig::Timeout.

Referenced by Security::PeerConnector::noteWantRead(), and Http::Tunneler::readMore().

◆ operator<<() [1/2]

std::ostream & Comm::operator<<	(	std::ostream &	os,
		const Connection &	conn
	)

Definition at line 194 of file Connection.cc.

References COMM_UNSET, conn, and hier_code_str.

◆ operator<<() [2/2]

std::ostream & Comm::operator<<	(	std::ostream &	os,
		const ConnectionPointer &	conn
	)

inline

Definition at line 198 of file Connection.h.

References conn.

◆ QuickPollRequired()

void Comm::QuickPollRequired ( void )

Definition at line 417 of file ModDevPoll.cc.

References max_poll_time.

Referenced by DiskdIOStrategy::init().

◆ Read()

void Comm::Read	(	const Comm::ConnectionPointer &	conn,
		AsyncCall::Pointer &	callback
	)

Start monitoring for read.

callback is scheduled when the read is possible, or on file descriptor close.

Definition at line 40 of file Read.cc.

References comm_read_base(), and conn.

Referenced by HttpStateData::maybeReadVirginBody(), Http::Tunneler::readMore(), Server::readSomeData(), Adaptation::Icap::Xaction::scheduleRead(), and ConnStateData::startPinnedConnectionMonitoring().

◆ ReadCancel()

void Comm::ReadCancel	(	int	fd,
		AsyncCall::Pointer &	callback
	)

Definition at line 219 of file Read.cc.

References Comm::IoCallback::active(), assert, Comm::IoCallback::callback, AsyncCall::cancel(), Comm::IoCallback::cancel(), COMM_SELECT_READ, COMMIO_FD_READCB, debugs, isOpen(), and SetSelect().

Referenced by Adaptation::Icap::Xaction::cancelRead(), Ftp::Server::closeDataConnection(), commStopHalfClosedMonitor(), Http::Tunneler::disconnect(), ConnStateData::stopPinnedConnectionMonitoring(), and Server::stopReading().

◆ ReadNow()

Comm::Flag Comm::ReadNow	(	CommIoCbParams &	params,
		SBuf &	buf
	)

Perform a read(2) on a connection immediately.

If params.size is non-zero will limit size of the read to either the buffer free space or params.size, whichever is smallest.

The returned flag is also placed in params.flag.

Return values

Comm::OK	data has been read and placed in buf, amount in params.size
Comm::COMM_ERROR	an error occurred, the code is placed in params.xerrno
Comm::INPROGRESS	unable to read at this time, or a minor error occurred
Comm::ENDFILE	0-byte read has occurred. Usually indicates the remote end has disconnected.

Definition at line 81 of file Read.cc.

References COMM_ERROR, CommCommonCbParams::conn, debugs, ENDFILE, Comm::Connection::fd, fd_bytes(), FD_READ, FD_READ_METHOD(), CommCommonCbParams::flag, ignoreErrno(), INPROGRESS, OK, SBuf::rawAppendFinish(), SBuf::rawAppendStart(), StatCounters::reads, CommIoCbParams::size, StatCounters::sock, SBuf::spaceSize(), statCounter, StatCounters::syscalls, CommCommonCbParams::xerrno, and xstrerr().

Referenced by Server::doClientRead(), Http::Tunneler::handleReadyRead(), Adaptation::Icap::Xaction::noteCommRead(), and HttpStateData::readReply().

◆ ResetSelect()

void Comm::ResetSelect ( int fd )

inline

Definition at line 30 of file Loops.h.

References COMM_SELECT_READ, COMM_SELECT_WRITE, and SetSelect().

Referenced by fd_close(), and ConnStateData::parseTlsHandshake().

◆ SelectLoopInit()

void Comm::SelectLoopInit ( void )

Initialise /dev/poll support.

Allocates memory, opens /dev/poll device handle.

Definition at line 176 of file ModDevPoll.cc.

References commDevPollRegisterWithCacheManager(), devpoll_fd, DEVPOLL_QUERYSIZE, devpoll_state, devpoll_update, DEVPOLL_UPDATESIZE, do_poll, dpoll_nfds, fatalf(), fd_open(), FD_UNKNOWN, xcalloc(), and xstrerr().

Referenced by comm_init().

◆ SetSelect()

void Comm::SetSelect	(	int	fd,
		unsigned int	type,
		PF *	handler,
		void *	client_data,
		time_t	timeout
	)

Set polling state of file descriptor and callback functions.

Sets requested polling state for given file handle along with desired callback function in the event the request event triggers.

Note that setting a polling state with a NULL callback function will clear the polling for that event on that file descriptor.

Parameters

fd	file descriptor to change
type	may be COMM_SELECT_READ (input) or COMM_SELECT_WRITE (output)
handler	callback function, or NULL to stop type of polling
client_data	pointer to be provided to call back function
timeout	if non-zero then timeout relative to now

This is a needed exported function which will be called to register and deregister interest in a pending IO state for a given FD.

Definition at line 223 of file ModDevPoll.cc.

References assert, COMM_SELECT_READ, COMM_SELECT_WRITE, comm_update_fd(), debugs, devpoll_state, F(), fd_table, handler(), NULL, squid_curtime, and _devpoll_state::state.

Referenced by _comm_close(), Comm::TcpAcceptor::acceptOne(), checkTimeouts(), Comm::ConnOpener::cleanFd(), clientNegotiateSSL(), comm_read_base(), comm_read_cancel(), diskHandleRead(), diskHandleWrite(), Comm::ConnOpener::doConnect(), ConnStateData::doPeekAndSpliceStep(), DoSelect(), htcpIncomingConnectionOpened(), htcpOpenPorts(), htcpRecv(), htcpSocketShutdown(), httpsEstablish(), icpConnectionShutdown(), icpHandleUdp(), icpIncomingConnectionOpened(), icpOpenPorts(), icpUdpSend(), idnsRead(), Dns::Init(), CommIO::Initialize(), logfileHandleWrite(), logfileQueueWrite(), Security::PeerConnector::noteWantRead(), Security::PeerConnector::noteWantWrite(), CommIO::NULLFDHandler(), IcmpSquid::Open(), ReadCancel(), IcmpSquid::Recv(), ResetSelect(), MessageBucket::scheduleWrite(), Comm::IoCallback::selectOrQueueWrite(), snmpHandleUdp(), snmpPortOpened(), Comm::TcpAcceptor::start(), ConnStateData::tunnelOnError(), wccp2ConnectionOpen(), wccp2HandleUdp(), wccpConnectionOpen(), and wccpHandleUdp().

◆ Write() [1/2]

void Comm::Write	(	const Comm::ConnectionPointer &	conn,
		const char *	buf,
		int	size,
		AsyncCall::Pointer &	callback,
		FREE *	free_func
	)

Queue a write. callback is scheduled when the write completes, on error, or on file descriptor close.

free_func is used to free the passed buffer when the write has completed.

Definition at line 33 of file Write.cc.

References Comm::IoCallback::active(), assert, COMMIO_FD_WRITECB, Comm::IoCallback::conn, conn, debugs, fd_table, IOCB_WRITE, Comm::IoCallback::selectOrQueueWrite(), Comm::IoCallback::setCallback(), size, and squid_curtime.

Referenced by Ftp::Server::acceptDataConnection(), errorSend(), HttpStateData::finishingBrokenPost(), HttpStateData::finishingChunkedRequest(), Ftp::Server::handleDataReply(), helperDispatch(), helperDispatchWriteDone(), helperStatefulDispatch(), idnsDoSendQueryVC(), Mgr::StoreToCommWriter::scheduleCommWrite(), Adaptation::Icap::Xaction::scheduleWrite(), Client::sendMoreRequestBody(), HttpStateData::sendRequest(), ClientHttpRequest::sslBumpStart(), Mgr::Inquirer::start(), whoisStart(), Ipc::UdsSender::write(), TunnelStateData::Connection::write(), Write(), Server::write(), Ftp::Client::writeCommand(), Http::One::Server::writeControlMsgAndCall(), Ftp::Server::writeEarlyReply(), Ftp::Server::writeForwardedReplyAndCall(), Log::TcpLogger::writeIfPossible(), Ftp::Server::writeReply(), and Http::Tunneler::writeRequest().

◆ Write() [2/2]

void Comm::Write	(	const Comm::ConnectionPointer &	conn,
		MemBuf *	mb,
		AsyncCall::Pointer &	callback
	)

Queue a write. callback is scheduled when the write completes, on error, or on file descriptor close.

Definition at line 27 of file Write.cc.

References MemBuf::buf, conn, MemBuf::freeFunc(), MemBuf::size, and Write().

◆ WriteCancel()

void Comm::WriteCancel	(	const Comm::ConnectionPointer &	conn,
		const char *	reason
	)

Variable Documentation

◆ HandleRead

void Comm::HandleRead

extern

Handle an FD which is ready for read(2).

If there is no provided buffer to fill call the callback.

Otherwise attempt a read into the provided buffer. If the read attempt succeeds or fails, call the callback. Else, wait for another IO notification.

Definition at line 128 of file Read.cc.

Referenced by comm_read_base().

◆ HandleWrite

void Comm::HandleWrite

Write to FD. This function is used by the lowest level of IO loop which only has access to FD numbers. We have to use the comm iocb_table to map FD numbers to waiting data and Comm::Connections. Once the write has been concluded we schedule the waiting call with success/fail results.

Definition at line 33 of file forward.h.

Referenced by checkTimeouts(), MessageBucket::scheduleWrite(), and Comm::IoCallback::selectOrQueueWrite().

◆ iocb_table

Comm::CbEntry * Comm::iocb_table

extern

Table of scheduled IO events which have yet to be processed ?? Callbacks which might be scheduled in future are stored in fd_table.

Definition at line 19 of file IoCallback.cc.

Referenced by CallbackTableDestruct(), and CallbackTableInit().

squid-cache.org

Optimising Web Delivery

Classes

Typedefs

Enumerations

Functions

Variables