A network communications channel. More...

#include <socket.h>

Inheritance diagram for PSocket:

Collaboration diagram for PSocket:

Classes
class	SelectList
	List of sockets used for Select() function. More...

struct	Slice
	Structure that defines a "slice" of memory to be written to. More...

Public Member Functions
virtual bool	Read (void *ptr, PINDEX len)
	Low level read from the channel. More...

virtual bool	Write (const void *buf, PINDEX len)
	Low level write to the channel. More...

	~PSocket ()

Socket options functions
PBoolean	SetOption (int option, int value, int level=SOL_SOCKET)
	Set options on the socket. More...

PBoolean	SetOption (int option, const void *valuePtr, PINDEX valueSize, int level=SOL_SOCKET)
	Set options on the socket. More...

PBoolean	GetOption (int option, int &value, int level=SOL_SOCKET)
	Get options on the socket. More...

PBoolean	GetOption (int option, void *valuePtr, PINDEX valueSize, int level=SOL_SOCKET)
	Get options on the socket. More...

Scattered read/write functions
virtual bool	Read (Slice *slices, size_t sliceCount)
	Low level scattered read from the channel. More...

virtual bool	Write (const Slice *slices, size_t sliceCount)
	Low level scattered write to the channel. More...

Public Member Functions inherited from PChannel
PBoolean	SetErrorValues (Errors errorCode, int osError, ErrorGroup group=LastGeneralError)
	Set error values to those specified. More...

virtual Comparison	Compare (const PObject &obj) const
	Get the relative rank of the two strings. More...

virtual PINDEX	HashFunction () const
	Calculate a hash value for use in sets and dictionaries. More...

virtual PBoolean	IsOpen () const
	Determine if the channel is currently open. More...

virtual PString	GetName () const
	Get the platform and I/O channel type name of the channel. More...

virtual P_INT_PTR	GetHandle () const
	Get the integer operating system handle for the channel. More...

FILE *	FDOpen (const char *mode)
	Re-open the device using the stdio library. More...

virtual PChannel *	GetBaseReadChannel () const
	Get the base channel of channel indirection using PIndirectChannel. More...

virtual PChannel *	GetBaseWriteChannel () const
	Get the base channel of channel indirection using PIndirectChannel. More...

void	SetReadTimeout (const PTimeInterval &time)
	Set the timeout for read operations. More...

PTimeInterval	GetReadTimeout () const
	Get the timeout for read operations. More...

PINDEX	GetLastReadCount () const
	Get the number of bytes read by the last Read() call. More...

virtual int	ReadChar ()
	Read a single character from the channel. More...

PBoolean	ReadBlock (void *buf, PINDEX len)
	Read len bytes into the buffer from the channel. More...

PString	ReadString (PINDEX len)
	Read `len` character into a string from the channel. More...

void	SetWriteTimeout (const PTimeInterval &time)
	Set the timeout for write operations to complete. More...

PTimeInterval	GetWriteTimeout () const
	Get the timeout for write operations to complete. More...

virtual PBoolean	Write (const void buf, PINDEX len, const void )
	Low level write to the channel with marker. More...

virtual PINDEX	GetLastWriteCount () const
	Get the number of bytes written by the last Write() call. More...

PBoolean	WriteChar (int c)
	Write a single character to the channel. More...

PBoolean	WriteString (const PString &str)
	Write a string to the channel. More...

	~PChannel ()
	Close down the channel. More...

Errors	GetErrorCode (ErrorGroup group=NumErrorGroups) const
	Get normalised error code. More...

int	GetErrorNumber (ErrorGroup group=NumErrorGroups) const
	Get OS errro code. More...

virtual PString	GetErrorText (ErrorGroup group=NumErrorGroups) const
	Get error message description. More...

virtual bool	ReadAsync (AsyncContext &context)
	Begin an asynchronous read from channel. More...

virtual void	OnReadComplete (AsyncContext &context)
	User callback function for when a `ReadAsync()` call has completed or timed out. More...

virtual bool	WriteAsync (AsyncContext &context)
	Begin an asynchronous write from channel. More...

virtual void	OnWriteComplete (AsyncContext &context)
	User callback function for when a WriteAsync() call has completed or timed out. More...

virtual PBoolean	Close ()
	Close the channel, shutting down the link to the data source. More...

virtual bool	SetLocalEcho (bool localEcho)
	Set local echo mode. More...

virtual bool	FlowControl (const void *flowData)
	Flow Control information Pass data to the channel for flowControl determination. More...

PBoolean	SetBufferSize (PINDEX newSize)
	Set the iostream buffer size for reads and writes. More...

PBoolean	SendCommandString (const PString &command)
	Send a command meta-string. More...

void	AbortCommandString ()
	Abort a command string that is in progress. More...

Public Member Functions inherited from PObject
unsigned	GetTraceContextIdentifier () const
	Get PTRACE context identifier. More...

void	SetTraceContextIdentifier (unsigned id)

void	GetTraceContextIdentifier (PObject &obj)

void	GetTraceContextIdentifier (PObject *obj)

void	SetTraceContextIdentifier (const PObject &obj)

void	SetTraceContextIdentifier (const PObject *obj)

virtual	~PObject ()

virtual PObject *	Clone () const
	Create a copy of the class on the heap. More...

template<class CLS >
CLS *	CloneAs () const
	As for Clone() but converts to specified type. More...

virtual const char *	GetClass (unsigned ancestor=0) const
	Get the current dynamic type of the object instance. More...

PBoolean	IsClass (const char *cls) const

virtual PBoolean	InternalIsDescendant (const char *clsName) const
	Determine if the dynamic type of the current instance is a descendent of the specified class. More...

__inline const PObject *	PTraceObjectInstance () const

virtual Comparison	CompareObjectMemoryDirect (const PObject &obj) const
	Determine the byte wise comparison of two objects. More...

bool	operator== (const PObject &obj) const
	Compare the two objects. More...

bool	operator!= (const PObject &obj) const
	Compare the two objects. More...

bool	operator< (const PObject &obj) const
	Compare the two objects. More...

bool	operator> (const PObject &obj) const
	Compare the two objects. More...

bool	operator<= (const PObject &obj) const
	Compare the two objects. More...

bool	operator>= (const PObject &obj) const
	Compare the two objects. More...

virtual void	PrintOn (ostream &strm) const
	Output the contents of the object to the stream. More...

virtual void	ReadFrom (istream &strm)
	Input the contents of the object from the stream. More...

Static Public Member Functions
Multiple socket selection functions
static int	Select (PSocket &sock1, PSocket &sock2)
	Select a socket with available data. More...

static int	Select (PSocket &sock1, PSocket &sock2, const PTimeInterval &timeout)
	Select a socket with available data. More...

static Errors	Select (SelectList &read)
	Select a socket with available data. More...

static Errors	Select (SelectList &read, const PTimeInterval &timeout)
	Select a socket with available data. More...

static Errors	Select (SelectList &read, SelectList &write)
	Select a socket with available data. More...

static Errors	Select (SelectList &read, SelectList &write, const PTimeInterval &timeout)
	Select a socket with available data. More...

static Errors	Select (SelectList &read, SelectList &write, SelectList &except)
	Select a socket with available data. More...

static Errors	Select (SelectList &read, SelectList &write, SelectList &except, const PTimeInterval &timeout)
	Select a socket with available data. More...

Integer conversion functions
static WORD	Host2Net (WORD v)
	Convert from host to network byte order. More...

static DWORD	Host2Net (DWORD v)
	Convert from host to network byte order. More...

static WORD	Net2Host (WORD v)
	Convert from network to host byte order. More...

static DWORD	Net2Host (DWORD v)
	Convert from network to host byte order. More...

Static Public Member Functions inherited from PChannel
static PString	GetErrorText (Errors lastError, int osError=0)
	Get error message description. More...

Protected Member Functions
	PSocket ()

virtual PBoolean	ConvertOSError (P_INT_PTR libcReturnValue, ErrorGroup group=LastGeneralError)
	Convert an operating system error into platform independent error. More...

virtual PBoolean	OpenSocket ()=0

virtual const char *	GetProtocolName () const =0
	This function returns the protocol name for the socket type. More...

int	os_close ()

int	os_socket (int af, int type, int proto)

PBoolean	os_connect (struct sockaddr *sin, socklen_t size)

PBoolean	os_vread (Slice slices, size_t sliceCount, int flags, struct sockaddr from, socklen_t *fromlen)

PBoolean	os_vwrite (const Slice slices, size_t sliceCount, int flags, struct sockaddr to, socklen_t tolen)

PBoolean	os_accept (PSocket &listener, struct sockaddr addr, socklen_t size)

virtual int	os_errno () const

Protected Member Functions inherited from PChannel
	PChannel (const PChannel &)

PChannel &	operator= (const PChannel &)

int	ReadCharWithTimeout (PTimeInterval &timeout)
	Read a character with specified timeout. More...

PBoolean	ReceiveCommandString (int nextChar, const PString &reply, PINDEX &pos, PINDEX start)

PBoolean	PXSetIOBlock (PXBlockType type, const PTimeInterval &timeout)

P_INT_PTR	GetOSHandleAsInt () const

int	PXClose ()

	PChannel ()
	Create the channel. More...

Protected Member Functions inherited from PObject
	PObject ()
	Constructor for PObject, made protected so cannot ever create one on its own. More...

Protected Attributes
WORD	port
	Port to be used by the socket when opening the channel. More...

Protected Attributes inherited from PChannel
P_INT_PTR	os_handle
	The operating system file handle return by standard open() function. More...

Errors	lastErrorCode [NumErrorGroups+1]
	The platform independant error code. More...

int	lastErrorNumber [NumErrorGroups+1]
	The operating system error number (eg as returned by errno). More...

PINDEX	lastReadCount
	Number of byte last read by the Read() function. More...

PINDEX	lastWriteCount
	Number of byte last written by the Write() function. More...

PTimeInterval	readTimeout
	Timeout for read operations. More...

PTimeInterval	writeTimeout
	Timeout for write operations. More...

PString	channelName
	Name of channel. More...

PMutex	px_threadMutex

PXBlockType	px_lastBlockType

PThread *	px_readThread

PThread *	px_writeThread

PMutex	px_writeMutex

PThread *	px_selectThread [3]

PMutex	px_selectMutex [3]

Protected Attributes inherited from PObject
unsigned	m_traceContextIdentifier

Socket establishment functions
enum	Reusability { CanReuseAddress, AddressIsExclusive }
	Flags to reuse of port numbers in Listen() function. More...

virtual PBoolean	Connect (const PString &address)
	Connect a socket to a remote host on the specified port number. More...

virtual PBoolean	Listen (unsigned queueSize=5, WORD port=0, Reusability reuse=AddressIsExclusive)
	Listen on a socket for a remote host on the specified port number. More...

virtual PBoolean	Accept (PSocket &socket)
	Open a socket to a remote host on the specified port number. More...

virtual PBoolean	Shutdown (ShutdownValue option)
	Close one or both of the data streams associated with a socket. More...

Port/Service database functions
virtual WORD	GetPortByService (const PString &service) const
	Get the port number for the specified service name. More...

virtual PString	GetServiceByPort (WORD port) const
	Get the service name from the port number. More...

void	SetPort (WORD port)
	Set the port number for the channel. More...

void	SetPort (const PString &service)
	Set the port number for the channel. More...

WORD	GetPort () const
	Get the port the TCP socket channel object instance is using. More...

PString	GetService () const
	Get a service name for the port number the TCP socket channel object instance is using. More...

static WORD	GetProtocolByName (const PString &name)
	Get the number of the protocol associated with the specified name. More...

static PString	GetNameByProtocol (WORD proto)
	Get the name of the protocol number specified. More...

static WORD	GetPortByService (const char *protocol, const PString &service)
	Get the port number for the specified service name. More...

static PString	GetServiceByPort (const char *protocol, WORD port)
	Get the service name from the port number. More...

Additional Inherited Members
Public Types inherited from PChannel
enum	PXBlockType { PXReadBlock, PXWriteBlock, PXAcceptBlock, PXConnectBlock }

enum	Errors { NoError, NotFound, FileExists, DiskFull, AccessDenied, DeviceInUse, BadParameter, NoMemory, NotOpen, Timeout, Interrupted, BufferTooSmall, Miscellaneous, ProtocolFailure, Unavailable, NumNormalisedErrors }
	Normalised error codes. More...

enum	ErrorGroup { LastReadError, LastWriteError, LastGeneralError, NumErrorGroups }
	Error groups. More...

typedef PNotifierTemplate < PChannel::AsyncContext & >	AsyncNotifier

enum	ShutdownValue { ShutdownRead = 0, ShutdownWrite = 1, ShutdownReadAndWrite = 2 }

Friends inherited from PObject

Detailed Description

A network communications channel.

This is based on the concepts in the Berkley Sockets library.

A socket represents a bidirectional communications channel to a port at a remote host.

Member Enumeration Documentation

enum PSocket::Reusability

Flags to reuse of port numbers in Listen() function.

Enumerator
CanReuseAddress
AddressIsExclusive

Constructor & Destructor Documentation

PSocket::PSocket ( )

protected

PSocket::~PSocket ( )

Member Function Documentation

virtual PBoolean PSocket::Accept ( PSocket & socket )

virtual

Open a socket to a remote host on the specified port number.

This is an "accepting" socket. When a "listening" socket has a pending connection to make, this will accept a connection made by the "connecting" socket created to establish a link.

The port that the socket uses is the one used in the Listen() command of the socket parameter. Note an error occurs if the socket parameter has not had the Listen() function called on it.

Note that this function will block until a remote system connects to the port number specified in the "listening" socket. The time that the function will block is determined by the read timeout of the socket parameter. This will normally be PMaxTimeInterval which indicates an infinite time.

The default behaviour is to assert.

Returns: true if the channel was successfully opened.

Parameters

socket Listening socket making the connection.

Reimplemented in PSocksSocket, PTelnetSocket, and PTCPSocket.

virtual PBoolean PSocket::Connect ( const PString & address )

virtual

Connect a socket to a remote host on the specified port number.

This is typically used by the client or initiator of a communications channel. This connects to a "listening" socket at the other end of the communications channel.

Use the SetReadTimeout() function to set a maximum time for the Connect().

Returns: true if the channel was successfully connected to the remote host.

Parameters

address Address of remote machine to connect to.

Reimplemented in PIPSocket, PSocksUDPSocket, PEthSocket, PSocksSocket, PTelnetSocket, and PUDPSocket.

virtual PBoolean PSocket::ConvertOSError	(	P_INT_PTR	libcReturnValue,
		ErrorGroup	group = `LastGeneralError`
	)

protectedvirtual

Convert an operating system error into platform independent error.

The internal error codes are set by this function. They may be obtained via the GetErrorCode() and GetErrorNumber() functions.

Returns: true if there was no error.

Reimplemented from PChannel.

static PString PSocket::GetNameByProtocol ( WORD proto )

static

Get the name of the protocol number specified.

Returns: Name of protocol or the number if the protocol was not found.

Parameters

proto Number of protocol.

PBoolean PSocket::GetOption	(	int	option,
		int &	value,
		int	level = `SOL_SOCKET`
	)

Get options on the socket.

These options are defined as Berkeley socket options of the class SOL_SOCKET.

Returns: true if the option was successfully retrieved.

Parameters

option	Option to get.
value	Integer to receive value.
level	Level for option.

PBoolean PSocket::GetOption	(	int	option,
		void *	valuePtr,
		PINDEX	valueSize,
		int	level = `SOL_SOCKET`
	)

Get options on the socket.

These options are defined as Berkeley socket options of the class SOL_SOCKET.

Returns: true if the option was successfully retrieved.

Parameters

option	Option to get.
valuePtr	Pointer to buffer for value.
valueSize	Size of buffer to receive value.
level	Level for option

WORD PSocket::GetPort ( ) const

Get the port the TCP socket channel object instance is using.

Returns: Port number.

virtual WORD PSocket::GetPortByService ( const PString & service ) const

virtual

Get the port number for the specified service name.

Parameters

service Name of service to get port number for.

static WORD PSocket::GetPortByService	(	const char *	protocol,
		const PString &	service
	)

static

Get the port number for the specified service name.

A name is a unique string contained in a system database. The parameter here may be either this unique name, an integer value or both separated by a space (name then integer). In the latter case the integer value is used if the name cannot be found in the database.

The exact behviour of this function is dependent on whether TCP or UDP transport is being used. The PTCPSocket and PUDPSocket classes will implement this function.

The static version of the function is independent of the socket type as its first parameter may be "tcp" or "udp".

Returns: Port number for service name, or 0 if service cannot be found.

Parameters

protocol	Protocol type for port lookup.
service	Name of service to get port number for.

static WORD PSocket::GetProtocolByName ( const PString & name )

static

Get the number of the protocol associated with the specified name.

Returns: Number of protocol or 0 if the protocol was not found.

Parameters

name	Name of protocol.

virtual const char* PSocket::GetProtocolName ( ) const

protectedpure virtual

This function returns the protocol name for the socket type.

Implemented in PEthSocket, PTCPSocket, PUDPSocket, and PICMPSocket.

PString PSocket::GetService ( ) const

Get a service name for the port number the TCP socket channel object instance is using.

Returns: String service name or a string representation of the port number if no service with that number can be found.

virtual PString PSocket::GetServiceByPort ( WORD port ) const

virtual

Get the service name from the port number.

Parameters

port	Number for service to find name of.

static PString PSocket::GetServiceByPort	(	const char *	protocol,
		WORD	port
	)

static

Get the service name from the port number.

A service name is a unique string contained in a system database. The parameter here may be either this unique name, an integer value or both separated by a space (name then integer). In the latter case the integer value is used if the name cannot be found in the database.

The exact behviour of this function is dependent on whether TCP or UDP transport is being used. The PTCPSocket and PUDPSocket classes will implement this function.

The static version of the function is independent of the socket type as its first parameter may be "tcp" or "udp".

Returns: Service name for port number.

Parameters

protocol	Protocol type for port lookup
port	Number for service to find name of.

static WORD PSocket::Host2Net ( WORD v )

inlinestatic

Convert from host to network byte order.

static DWORD PSocket::Host2Net ( DWORD v )

inlinestatic

Convert from host to network byte order.

virtual PBoolean PSocket::Listen	(	unsigned	queueSize = `5`,
		WORD	port = `0`,
		Reusability	reuse = `AddressIsExclusive`
	)

virtual

Listen on a socket for a remote host on the specified port number.

This may be used for server based applications. A "connecting" socket begins a connection by initiating a connection to this socket. An active socket of this type is then used to generate other "accepting" sockets which establish a two way communications channel with the "connecting" socket.

If the port parameter is zero then the port number as defined by the object instance construction or the descendent classes SetPort() or SetService() function.

Returns: true if the channel was successfully opened.

Parameters

queueSize	Number of pending accepts that may be queued.
port	Port number to use for the connection.
reuse	Can/Cant listen more than once.

Reimplemented in PIPSocket, PSocksUDPSocket, PEthSocket, and PSocksSocket.

static WORD PSocket::Net2Host ( WORD v )

inlinestatic

Convert from network to host byte order.

static DWORD PSocket::Net2Host ( DWORD v )

inlinestatic

Convert from network to host byte order.

virtual PBoolean PSocket::OpenSocket ( )

protectedpure virtual

Implemented in PEthSocket, PTCPSocket, PUDPSocket, and PICMPSocket.

PBoolean PSocket::os_accept	(	PSocket &	listener,
		struct sockaddr *	addr,
		socklen_t *	size
	)

protected

int PSocket::os_close ( )

protected

PBoolean PSocket::os_connect	(	struct sockaddr *	sin,
		socklen_t	size
	)

protected

virtual int PSocket::os_errno ( ) const

protectedvirtual

Reimplemented from PChannel.

int PSocket::os_socket	(	int	af,
		int	type,
		int	proto
	)

protected

PBoolean PSocket::os_vread	(	Slice *	slices,
		size_t	sliceCount,
		int	flags,
		struct sockaddr *	from,
		socklen_t *	fromlen
	)

protected

PBoolean PSocket::os_vwrite	(	const Slice *	slices,
		size_t	sliceCount,
		int	flags,
		struct sockaddr *	to,
		socklen_t	tolen
	)

protected

virtual bool PSocket::Read	(	void *	buf,
		PINDEX	len
	)

virtual

Low level read from the channel.

This function may block until the requested number of characters were read or the read timeout was reached. The GetLastReadCount() function returns the actual number of bytes read.

The GetErrorCode() function should be consulted after Read() returns false to determine what caused the failure.

Returns: true indicates that at least one character was read from the channel. false means no bytes were read due to timeout or some other I/O error.

Reimplemented from PChannel.

Reimplemented in PEthSocket, PUDPSocket, PTelnetSocket, and PTCPSocket.

virtual bool PSocket::Read	(	Slice *	slices,
		size_t	sliceCount
	)

virtual

Low level scattered read from the channel.

This is identical to Read except that the data will be read into a series of scattered memory slices. By default, this call will default to calling Read multiple times, but this may be implemented by operating systems to do a real scattered read

Returns: true indicates that at least one character was read from the channel. false means no bytes were read due to timeout or some other I/O error.

static int PSocket::Select	(	PSocket &	sock1,
		PSocket &	sock2
	)

static