A datagram socket to be used for multicasts. More...

#include <Socket.h>

Inheritance diagram for nidas::util::MulticastSocket:

Public Member Functions
	MulticastSocket () throw (IOException)
	Create an unbound multicast socket. More...

	MulticastSocket (int port) throw (IOException)
	Create multicast socket, bind it to a local port. More...

	throw (IOException)
	Creates a datagram socket and binds it to the specified local address. More...

void	joinGroup (Inet4Address groupAddr) throw (IOException)
	Join a multicast group on all interfaces. More...

void	joinGroup (Inet4Address groupAddr, const Inet4NetworkInterface &iface) throw (IOException)
	Join a multicast group on a given interface. More...

void	leaveGroup (Inet4Address groupAddr) throw (IOException)
	Leave a multicast group on all interfaces. More...

void	leaveGroup (Inet4Address groupAddr, const Inet4NetworkInterface &iface) throw (IOException)
	Leave a multicast group on a given interface. More...

void	setTimeToLive (int val) throw (IOException)

int	getTimeToLive () const throw (IOException)

void	setMulticastLoop (bool val) throw (IOException)
	Whether to set the IP_MULTICAST_LOOP socket option. More...

bool	getMulticastLoop () const throw (IOException)

void	setInterface (Inet4Address maddr, const Inet4NetworkInterface &iface) throw (IOException)
	Set the interface for a given multicast address. More...

void	setInterface (Inet4Address iaddr) throw (IOException)
	Set the interface for a given multicast address. More...

Inet4NetworkInterface	getInterface () const throw (IOException)

Inet4NetworkInterface	findInterface (const Inet4Address &iaddr) const throw (IOException)

std::list< Inet4NetworkInterface >	getInterfaces () const throw (IOException)
	Return the IP addresses of all my network interfaces. More...

void	close () throw (IOException)

void	setTimeout (int val)
	Set the timeout for receive(), recv(), and recvfrom() methods. More...

void	connect (const std::string &host, int port) throw (UnknownHostException,IOException)
	Datagrams are connectionless, so this doesn't establish a true connection, it just sets the default destination address for the send() calls. More...

void	connect (const Inet4Address &addr, int port) throw (IOException)
	Datagrams are connectionless, so this doesn't establish a true connection, it just sets the default destination address for the send() calls. More...

void	connect (const SocketAddress &addr) throw (IOException)
	Datagrams are connectionless, so this doesn't establish a true connection, it just sets the default destination address for the send() calls. More...

void	bind (const Inet4Address &addr, int port) throw (IOException)
	Bind the DatagramSocket to the specified local address. More...

void	bind (const SocketAddress &addr) throw (IOException)
	Bind the DatagramSocket to the specified local address. More...

int	getFd () const

void	receive (DatagramPacketBase &packet) throw (IOException)
	Read a packet from the DatagramSocket. More...

void	receive (DatagramPacketBase &packet, Inet4PacketInfo &info, int flags=0) throw (IOException)
	Read a packet from the DatagramSocket. More...

void	send (const DatagramPacketBase &packet, int flags=0) throw (IOException)

size_t	send (const void *buf, size_t len, int flags=0) throw (IOException)

size_t	send (const struct iovec *iov, int iovcnt, int flags=MSG_NOSIGNAL) throw (IOException)

size_t	recv (void *buf, size_t len, int flags=0) throw (IOException)

size_t	recvfrom (void *buf, size_t len, int flags, SocketAddress &from) throw (IOException)

size_t	sendto (const void *buf, size_t len, int flags, const SocketAddress &to) throw (IOException)

size_t	sendto (const struct iovec *iov, int iovcnt, int flags, const SocketAddress &to) throw (IOException)

const SocketAddress &	getLocalSocketAddress () const throw ()
	Get local address of this socket. More...

int	getLocalPort () const throw ()
	Get local port number of this socket. More...

void	setNonBlocking (bool val) throw (IOException)
	Do fcntl system call to set O_NONBLOCK file descriptor flag on the socket. More...

bool	isNonBlocking () const throw (IOException)

void	setReceiveBufferSize (int size) throw (IOException)

int	getReceiveBufferSize () throw (IOException)

void	setSendBufferSize (int size) throw (IOException)

int	getSendBufferSize () throw (IOException)

void	setBroadcastEnable (bool val) throw (IOException)

bool	getBroadcastEnable () const throw (IOException)

void	setPktInfo (bool val) throw (IOException)
	Control whether a IP_PKTINFO ancillary message is received with each datagram. More...

Protected Attributes
SocketImpl	_impl

Detailed Description

A datagram socket to be used for multicasts.

This class provides the default public copy constructors and assignment operators. Objects of this class can be copied and assigned to without restriction. However, because of this, the destructor does not close the socket, so, in general, you should make sure that the socket is closed once at some point.

Usage example:

// host A listens for multicasts to address 239.0.0.1, port 9000:
MulticastSocket msock(9000);
// join the multicast group in whatever interface the system chooses,
// typically the first ethernet interface.
msock.joinGroup(Inet4Address::getByName("239.0.0.1"));
char buf[512];
Inet4SocketAddress from;
for (;;) {
    msock.recvfrom(buf,sizeof(buf),0,from);
    ...
}
// how to join on all multicast and loopback interfaces
// note that multicast works over the loopback interface
list<Inet4NetworkInterface> ifaces = msock.getInterfaces();
for (list<Inet4NetworkInterface>::const_iterator ii = ifaces.begin();
      ii != ifaces.end(); ++ii)
{
      if ((ii->getFlags() & (IFF_LOOPBACK | IFF_MULTICAST)) && (ii->getFlags() & IFF_UP))
          msock.joinGroup(Inet4Address::getByName("239.0.0.1"),*ii);
}
// host B multicasts to address 239.0.0.1, port 9000:
DatagramSocket msock;
Inet4Address maddr = Inet4Address::getByName("239.0.0.1");
Inet4SocketAddress msaddr = Inet4SocketAddress(maddr,9000);
for (;;) {
    msock.sendto("hello\n",6,0,msaddr);
    ...
}
// host C also does similar multicasts, but uses MulticastSocket
// methods to send packets out a specific interface, and
// to set the time to live (TTL) parameter.
MulticastSocket msock;
Inet4Address maddr = Inet4Address::getByName("239.0.0.1");
list<Inet4NetworkInterfaces> ifaces = msock.getInterfaces();
list<Inet4NetworkInterfaces>::const_iterator ii; 
for (ii = ifaces.begin(); ii != ifaces.end(); ++ii) {
  Inet4NetworkInterface ni = *ii;
  if (ni.getName() == "eth1")
      msock.setInterface(maddr,ni);
}
msock.setTimeToLive(2);  // go through one router
Inet4SocketAddress msaddr = Inet4SocketAddress(maddr,9000);
for (;;) {
    msock.sendto("hello\n",6,0,msaddr);
    ...
}

Note: if the above examples are not working for you, check your firewall settings. They might be blocking multicasts.

Constructor & Destructor Documentation

nidas::util::MulticastSocket::MulticastSocket	(		)
throw	(	IOException
	)

inline

Create an unbound multicast socket.

You must bind it to a port if you want to receive packets. If you are sending packets on this MulticastSocket, and do not use getInterfaces() and setInterface() to choose a specific interface, the system sends packets out on the first non-loopback interface that it finds. If a firewall is blocking multicast packets on that interface the packets won't be sent.

nidas::util::MulticastSocket::MulticastSocket	(	int	port	)
throw	(	IOException
	)

inline

Create multicast socket, bind it to a local port.

Member Function Documentation

void nidas::util::DatagramSocket::bind	(	const Inet4Address &	addr,
		int	port
	)
throw	(	IOException
	)

inlineinherited

Bind the DatagramSocket to the specified local address.

The address should correspond to the address of a local interface. Only packets sent to the given port and interface, by unicast, broadcast or multicast will be received.

Referenced by nidas::core::DatagramSocket::connect(), and nidas::core::DerivedDataReader::run().

void nidas::util::DatagramSocket::bind	(	const SocketAddress &	addr	)
throw	(	IOException
	)

inlineinherited

Bind the DatagramSocket to the specified local address.

The address should correspond to the address of a local interface. Only packets sent to the given port and interface, by unicast, broadcast or multicast will be received.

void nidas::util::DatagramSocket::close	(		)
throw	(	IOException
	)

inlineinherited

Referenced by nidas::core::MultipleUDPSockets::close(), nidas::core::UDPSocketIODevice::close(), nidas::core::DatagramSocket::close(), PacketReader::loop(), nidas::core::StatusListener::run(), nidas::core::DerivedDataReader::run(), nidas::core::DSMEngineStat::run(), nidas::util::McSocketListener::run(), nidas::util::McSocketMulticaster< SocketTT >::run(), nidas::util::McSocketListener::~McSocketListener(), and nidas::util::McSocketMulticaster< SocketTT >::~McSocketMulticaster().

void nidas::util::DatagramSocket::connect	(	const std::string &	host,
		int	port
	)
throw	(	UnknownHostException,
		IOException
	)

inlineinherited

Datagrams are connectionless, so this doesn't establish a true connection, it just sets the default destination address for the send() calls.

Referenced by nidas::core::DatagramSocket::connect(), and nidas::util::McSocketListener::run().

void nidas::util::DatagramSocket::connect	(	const Inet4Address &	addr,
		int	port
	)
throw	(	IOException
	)

inlineinherited

Datagrams are connectionless, so this doesn't establish a true connection, it just sets the default destination address for the send() calls.

void nidas::util::DatagramSocket::connect	(	const SocketAddress &	addr	)
throw	(	IOException
	)

inlineinherited

Datagrams are connectionless, so this doesn't establish a true connection, it just sets the default destination address for the send() calls.

Inet4NetworkInterface nidas::util::MulticastSocket::findInterface	(	const Inet4Address &	iaddr	)	const
throw	(	IOException
	)

inline

bool nidas::util::DatagramSocket::getBroadcastEnable	(		)	const
throw	(	IOException
	)

inlineinherited

int nidas::util::DatagramSocket::getFd ( ) const

inlineinherited

Referenced by nidas::core::UDPSocketIODevice::close(), nidas::core::MultipleUDPSockets::getFd(), nidas::core::DatagramSocket::getFd(), nidas::core::UDPSocketIODevice::getReadFd(), nidas::core::UDPSocketIODevice::getWriteFd(), nidas::core::DerivedDataReader::run(), nidas::util::McSocketListener::run(), and nidas::util::McSocketMulticaster< SocketTT >::run().

Inet4NetworkInterface nidas::util::MulticastSocket::getInterface	(		)	const
throw	(	IOException
	)

inline

References nidas::util::Inet4NetworkInterface::getInterface().

std::list<Inet4NetworkInterface> nidas::util::MulticastSocket::getInterfaces	(		)	const
throw	(	IOException
	)

inline

Return the IP addresses of all my network interfaces.

Referenced by nidas::util::McSocket< SocketT >::getInterfaces(), nidas::util::listMulticastInterfaces(), nidas::core::StatusListener::run(), and nidas::core::DSMServerStat::run().

int nidas::util::DatagramSocket::getLocalPort	(	)	const
throw	(
	)

inlineinherited

Get local port number of this socket.

Referenced by nidas::core::StatusListener::run(), and nidas::util::McSocketMulticaster< SocketTT >::run().

const SocketAddress& nidas::util::DatagramSocket::getLocalSocketAddress	(	)	const
throw	(
	)

inlineinherited

Get local address of this socket.

Referenced by nidas::core::MultipleUDPSockets::handleChangedSockets(), nidas::core::StatusListener::run(), nidas::core::DerivedDataReader::run(), nidas::core::DSMEngineStat::run(), nidas::util::McSocketListener::run(), and nidas::util::McSocketMulticaster< SocketTT >::run().

bool nidas::util::MulticastSocket::getMulticastLoop	(		)	const
throw	(	IOException
	)

inline

int nidas::util::DatagramSocket::getReceiveBufferSize	(		)
throw	(	IOException
	)

inlineinherited

Referenced by nidas::core::MultipleUDPSockets::getBufferSize(), and nidas::core::DatagramSocket::getBufferSize().

int nidas::util::DatagramSocket::getSendBufferSize	(		)
throw	(	IOException
	)

inlineinherited

int nidas::util::MulticastSocket::getTimeToLive	(		)	const
throw	(	IOException
	)

inline

bool nidas::util::DatagramSocket::isNonBlocking	(		)	const
throw	(	IOException
	)

inlineinherited

Referenced by nidas::core::DatagramSocket::isNonBlocking().

void nidas::util::MulticastSocket::joinGroup	(	Inet4Address	groupAddr	)
throw	(	IOException
	)

inline

Join a multicast group on all interfaces.

Referenced by nidas::core::UDPSocketIODevice::open(), and nidas::core::StatusListener::run().

void nidas::util::MulticastSocket::joinGroup	(	Inet4Address	groupAddr,
		const Inet4NetworkInterface &	iface
	)
throw	(	IOException
	)

inline

Join a multicast group on a given interface.

void nidas::util::MulticastSocket::leaveGroup	(	Inet4Address	groupAddr	)
throw	(	IOException
	)

inline

Leave a multicast group on all interfaces.

void nidas::util::MulticastSocket::leaveGroup	(	Inet4Address	groupAddr,
		const Inet4NetworkInterface &	iface
	)
throw	(	IOException
	)

inline

Leave a multicast group on a given interface.

void nidas::util::DatagramSocket::receive	(	DatagramPacketBase &	packet	)
throw	(	IOException
	)

inlineinherited

Read a packet from the DatagramSocket.

On return, packet.getLength() will contain the number bytes received, and packet.getSocketAddress() will contain the address of the sender.

Referenced by PacketReader::loop(), nidas::core::DerivedDataReader::run(), nidas::util::McSocketListener::run(), and nidas::util::McSocketMulticaster< SocketTT >::run().

void nidas::util::DatagramSocket::receive	(	DatagramPacketBase &	packet,
		Inet4PacketInfo &	info,
		int	flags = `0`
	)
throw	(	IOException
	)

inlineinherited

Read a packet from the DatagramSocket.

On return, packet.getLength() will contain the number bytes received, and packet.getSocketAddress() will contain the address of the sender. info will contain the information on the local and destination addresses of the packet, and the interface it was received on. If setPktInfo(true) has not be set on this socket, then it is set prior to receiving the packet, and then unset after receipt of the packet.

size_t nidas::util::DatagramSocket::recv	(	void *	buf,
		size_t	len,
		int	flags = `0`
	)
throw	(	IOException
	)

inlineinherited

Referenced by nidas::core::UDPSocketIODevice::read(), and nidas::core::DatagramSocket::read().

size_t nidas::util::DatagramSocket::recvfrom	(	void *	buf,
		size_t	len,
		int	flags,
		SocketAddress &	from
	)
throw	(	IOException
	)

inlineinherited

References len.

Referenced by nidas::core::StatusListener::run().

void nidas::util::DatagramSocket::send	(	const DatagramPacketBase &	packet,
		int	flags = `0`
	)
throw	(	IOException
	)

inlineinherited

Referenced by nidas::util::McSocketMulticaster< SocketTT >::run(), nidas::core::UDPSocketIODevice::write(), and nidas::core::DatagramSocket::write().

size_t nidas::util::DatagramSocket::send	(	const void *	buf,
		size_t	len,
		int	flags = `0`
	)
throw	(	IOException
	)

inlineinherited

size_t nidas::util::DatagramSocket::send	(	const struct iovec *	iov,
		int	iovcnt,
		int	flags = `MSG_NOSIGNAL`
	)
throw	(	IOException
	)

inlineinherited

size_t nidas::util::DatagramSocket::sendto	(	const void *	buf,
		size_t	len,
		int	flags,
		const SocketAddress &	to
	)
throw	(	IOException
	)

inlineinherited

References len.

Referenced by nidas::core::StatusThread::sendStatus(), and nidas::core::MultipleUDPSockets::write().

size_t nidas::util::DatagramSocket::sendto	(	const struct iovec *	iov,
		int	iovcnt,
		int	flags,
		const SocketAddress &	to
	)
throw	(	IOException
	)

inlineinherited

void nidas::util::DatagramSocket::setBroadcastEnable	(	bool	val	)
throw	(	IOException
	)

inlineinherited

void nidas::util::MulticastSocket::setInterface	(	Inet4Address	maddr,
		const Inet4NetworkInterface &	iface
	)
throw	(	IOException
	)

inline

Set the interface for a given multicast address.

If you are sending packets on this MulticastSocket, and do not use setInterface() specific interface, the system will send packets out on the first interface that it finds that is capable of MULTICAST. See setInterface(Inet4Address maddr);

If there are no multicast interfaces that are UP, then the system may not choose the loopback interface by default. So doing multicast on a DHCP laptop that isn't connected to the net may give problems.

Referenced by nidas::core::MultipleUDPSockets::addClient(), nidas::core::DSMServerStat::run(), and nidas::util::McSocketMulticaster< SocketTT >::run().

void nidas::util::MulticastSocket::setInterface	(	Inet4Address	iaddr	)
throw	(	IOException
	)

inline

Set the interface for a given multicast address.

This uses the default value of INADDR_ANY for the specific interface, which causes the system to choose what it thinks is the most appropriate interface, typically the first ethernet interface on the system. If you have more than one candidate interface, you can add an entry in the routing table to indicate which you want to use: route add -host 239.0.0.10 dev eth1

void nidas::util::MulticastSocket::setMulticastLoop	(	bool	val	)
throw	(	IOException
	)

inline

Whether to set the IP_MULTICAST_LOOP socket option.

According to "man 7 ip", IP_MULTICAST_LOOP controls "whether sent multicast packets should be looped back to the local sockets." This is the default in Linux in that setting it does not seem to be necessary for a process on a host to receive multicast packets that are sent out on one of its interfaces, providing the multicast reader has joined that interface, and a firewall is not blocking them (a source of frustration!).

Referenced by nidas::core::MultipleUDPSockets::addClient().

void nidas::util::DatagramSocket::setNonBlocking	(	bool	val	)
throw	(	IOException
	)

inlineinherited

Do fcntl system call to set O_NONBLOCK file descriptor flag on the socket.

Parameters

val	true=set O_NONBLOCK, false=unset O_NONBLOCK.

Referenced by nidas::core::DatagramSocket::connect(), nidas::core::McSocketUDP::connect(), nidas::core::McSocketUDP::connected(), and nidas::core::DatagramSocket::setNonBlocking().

void nidas::util::DatagramSocket::setPktInfo	(	bool	val	)
throw	(	IOException
	)

inlineinherited

Control whether a IP_PKTINFO ancillary message is received with each datagram.

Only supported on DatagramSockets. The IP_PKTINFO message is converted to an Inet4PacketInfo object which is available via the getInet4PacketInfo() method.

Parameters

val,: if true enable the IP_PKTINFO message, if false, disable.

void nidas::util::DatagramSocket::setReceiveBufferSize	(	int	size	)
throw	(	IOException
	)

inlineinherited

void nidas::util::DatagramSocket::setSendBufferSize	(	int	size	)
throw	(	IOException
	)

inlineinherited

void nidas::util::DatagramSocket::setTimeout ( int val )

inlineinherited

Set the timeout for receive(), recv(), and recvfrom() methods.

Parameters

val	timeout in milliseconds. 0=no timeout (infinite) The receive methods will return IOTimeoutException if an operation times out.

void nidas::util::MulticastSocket::setTimeToLive	(	int	val	)
throw	(	IOException
	)

inline

nidas::util::MulticastSocket::throw ( IOException )

inline

Creates a datagram socket and binds it to the specified local address.

Member Data Documentation

SocketImpl nidas::util::DatagramSocket::_impl

protectedinherited

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

nidas/util/Socket.h

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation