xref: /haiku/docs/user/net/DatagramSocket.dox (revision c8127e2b7d6e3e8497a38cb084301b0876aa15c5)

/*
 * Copyright 2013-2014 Haiku, Inc. All rights reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *		Adrien Destugues, pulkomandy@pulkomandy.tk
 *		Axel Dörfler, axeld@pinc-software.de
 *
 * Corresponds to:
 *		headers/os/net/DatagramSocket.h rev 43302
 *		src/kits/network/libnetapi/DatagramSocket.cpp rev 43302
 */

/*!
	\file DatagramSocket.h
	\ingroup network
	\brief BAbstractSocket implementation for datagram connections.
*/

/*!
	\class BDatagramSocket
	\ingroup network
	\brief BAbstractSocket implementation for datagram connections.

	Datagrams are atomic messages. There is no notion of sequence and the data
	sent in a sequence of write calls may not get to the other end of the
	connections in the same order. There is no flow control, so some of them
	may not even make it to the peer. The most well known datagram protocol
	is UDP, which also happens to be the only one that Haiku currently supports.

	The main uses for datagram sockets are when performance is more important
	than safety (the lack of acknowledge mechanism allows to send a lot of
	datagram packets at once, whereas TCP is limited by its sliding window
	mechanism), when the application wants to manage flow control and
	acknowledges itself (ie. when you want to implement your own protocol on
	top of UDP), and when lost packets don't matter (for example, in
	a video stream, there is no use for receiving late video frames if they
	were already skipped to play the following ones).

	Since UDP is a connectionless protocol, in order to specify the target,
	or to be able to know from where you got a packet, this class provides
	you with the extra methods SendTo() and ReceiveFrom().
*/

/*!
	\fn BDatagramSocket::BDatagramSocket()
	\brief Default constructor.

	Does nothing. Call Bind() or Connect() to actually start network
	communications.

	\see BAbstractSocket::BAbstractSocket().
*/

/*!
	\fn BDatagramSocket::BDatagramSocket(const BNetworkAddress& peer,
		bigtime_t timeout)
	\brief Create and connect a datagram socket.

	The socket is immediately connected to the given peer. Use InitCheck() to
	make sure the connection was successful.

	\param peer host to connect to
	\param timeout connection timeout, in microsecond.
*/

/*!
	\fn BDatagramSocket::BDatagramSocket(const BDatagramSocket& other)
	\brief Copy constructor.
*/

/*!
	\fn BDatagramSocket::~BDatagramSocket()
	\brief Destructor.

	The socket is disconnected.
*/

/*!
	\fn BDatagramSocket::SetBroadcast(bool broadcast)
	\brief enables or disable broadcast mode

	In broadcast mode, datagrams can be sent to multiple peers at once.
	Calling this method is not enough, you must also set your peer address to
	be \c INADDR_BROADCAST to effectively send a broadcast message.

	Note that broadcast messages usually don't propagate on Internet as they
	would generate too much traffic. Their use is thus restricted to local
	networks.

	\param broadcast the requested state for broadcast permissions.
	\return \c B_OK on success, or other error codes on failure.
*/

/*!
	\fn void BDatagramSocket::SetPeer(const BNetworkAddress& peer)
	\brief Change the remote host for this connections.

	Datagram connections are not statically bound to a remote address, so it is
	possible to change the destination of packets at runtime.

	Note that packets coming to the right local address, no matter where they
	come from, will always be accepted.

	\param peer the address to which following Write calls will send datagrams
*/

/*!
	\fn size_t BDatagramSocket::MaxTransmissionSize() const

	The maximum size for datagram sockets is 32768 bytes.

	\returns 32768
*/

/*!
	\fn ssize_t BDatagramSocket::SendTo(const BNetworkAddress& address,
		const void* buffer, size_t size)
	\brief Send a single datagram to the given address

	Unlike the Write() method, which always sends to the same peer, this method
	can be used to send messages to different destinations.

	\param address the host to send the datagram to
	\param buffer datagram contents
	\param size size of the buffer
	\returns the number of bytes sent, which may be less than requested, or a
		negative error code.
*/

/*!
	\fn ssize_t BDatagramSocket::ReceiveFrom(void* buffer, size_t bufferSize,
		BNetworkAddress& from)
	\brief receive a single datagram from a given host

	Receives a datagram, and fills the \a from address with the host that
	sent it.
	If the buffer is too small, extra bytes from the datagram will be lost.

	\param buffer the buffer to store the datagram in
	\param bufferSize size of the buffer
	\param from the datagram sender address
*/

/*!
	\fn ssize_t BDatagramSocket::Read(void* buffer, size_t size)
	\brief Receive a datagram from any sender

	This is similar to ReceiveFrom(), but there is no way to know who sent
	the message.

	If the buffer is too small, the remaining part of the datagram is lost.

	\param buffer memory to store the datagram in
	\param size the size of the buffer
	\return the number of bytes actually written, or a negative error code.
*/

/*!
	\fn ssize_t BDatagramSocket::Write(const void* buffer, size_t size)
	\brief Send a datagram to the default target

	If the socket is connected, send a datagram to the connected host.
	If it's not, send to the peer given to the SetPeer() function.

	\param buffer the datagram to send
	\param size the size of the message
	\return the number of bytes written, which may be less than requested, or
		a negative error code.
*/