Reference

UDPSocket(3cc)

UDP sockets implement the TCP SOCK_DGRAM UDP protocol. Unreliable Datagram Protocol sockets.

NAME

UDPSocket - UDP sockets implement the TCP SOCK_DGRAM UDP protocol. Unreliable Datagram Protocol sockets.

SYNOPSIS

#include <socket.h>

Inherits Socket.

Inherited by UDPBroadcast, UDPReceive [protected], and UDPTransmit [protected].

Public Methods

UDPSocket (void)
Create an unbound UDP socket, mostly for internal use. UDPSocket (const InetAddress &bind, tpport_t port)
Create a UDP socket and bind it to a specific interface and port address so that other UDP sockets on remote machines (or the same host) may find and send UDP messages to it. virtual ~UDPSocket ()
Destroy a UDP socket as a socket. void setPeer (const InetHostAddress &host, tpport_t port)
set the peer address to send message packets to. Socket::Error getInterfaceIndex (const char *ethX, int &InterfaceIndex)
get the interface index for a named network device Socket::Error join (const InetMcastAddress &ia, int InterfaceIndex)
join a multicast group on a particular interface int send (const void *buf, size_t len)
Send a message packet to a peer host. int receive (void *buf, size_t len)
Receive a message from any host. InetHostAddress getPeer (tpport_t *port=NULL) const
Examine address of sender of next waiting packet. int peek (void *buf, size_t len)
Examine contents of next waiting packet.

Protected Attributes

sockaddr_in peer

DETAILED DESCRIPTION

UDP sockets implement the TCP SOCK_DGRAM UDP protocol. Unreliable Datagram Protocol sockets.

They can be used to pass unverified messages between hosts, or to broadcast a specific message to an entire subnet. Please note that Streaming of realtime data commonly use UDPDuplex related classes rather than UDPSocket.

In addition to connected TCP sessions, Common C++ supports UDP sockets and these also cover a range of functionality. Like a TCPSocket, A UDPSocket can be created bound to a specific network interface and/or port address, though this is not required. UDP sockets also are usually either connected or otherwise 'associated' with a specific 'peer' UDP socket. Since UDP sockets operate through discreet packets, there are no streaming operators used with UDP sockets.

In addition to the UDP 'socket' class, there is a 'UDPBroadcast' class. The UDPBroadcast is a socket that is set to send messages to a subnet as a whole rather than to an individual peer socket that it may be associated with.

UDP sockets are often used for building 'realtime' media streaming protocols and full duplex messaging services. When used in this manner, typically a pair of UDP sockets are used together; one socket is used to send and the other to receive data with an associated pair of UDP sockets on a 'peer' host. This concept is represented through the Common C++ UDPDuplex object, which is a pair of sockets that communicate with another UDPDuplex pair.

Author: David Sugar <[email protected]>

CONSTRUCTOR & DESTRUCTOR DOCUMENTATION

UDPSocket::UDPSocket (void)

Create an unbound UDP socket, mostly for internal use.

UDPSocket::UDPSocket (const InetAddress & bind, tpport_t port)

Create a UDP socket and bind it to a specific interface and port address so that other UDP sockets on remote machines (or the same host) may find and send UDP messages to it.

On failure to bind, an exception is thrown.

Parameters:

bind

address to bind this socket to.

port

number to bind this socket to.

virtual UDPSocket::~UDPSocket () [virtual]

Destroy a UDP socket as a socket.

MEMBER FUNCTION DOCUMENTATION

Socket::Error UDPSocket::getInterfaceIndex (const char * ethX, int & InterfaceIndex)

get the interface index for a named network device

Parameters:

ethX

is device name, like 'eth0' or 'eth1'

InterfaceIndex

is the index value returned by os

Todo:
Win32 implementation.

InetHostAddress UDPSocket::getPeer (tpport_t * port = NULL) const

Examine address of sender of next waiting packet.

This also sets 'peer' address to the sender so that the next 'send' message acts as a 'reply'. This additional behavior overides the standard socket getSender behavior.

Parameters:

port

pointer to hold port number.

Reimplemented from Socket.

Socket::Error UDPSocket::join (const InetMcastAddress & ia, int InterfaceIndex)

join a multicast group on a particular interface

Parameters:

ia

is the multicast address to use

InterfaceIndex

is the index value returned by getInterfaceIndex

Todo:
Win32 implementation.

int UDPSocket::peek (void * buf, size_t len) [inline]

Examine contents of next waiting packet.

Parameters:

buf

pointer to packet buffer for contents.

len

of packet buffer.

Returns: number of bytes examined.

int UDPSocket::receive (void * buf, size_t len) [inline]

Receive a message from any host.

Parameters:

buf

pointer to packet buffer to receive.

len

of packet buffer to receive.

Returns: number of bytes received.

Reimplemented in UDPReceive.

int UDPSocket::send (const void * buf, size_t len) [inline]

Send a message packet to a peer host.

Parameters:

buf

pointer to packet buffer to send.

len

of packet buffer to send.

Returns: number of bytes sent.

void UDPSocket::setPeer (const InetHostAddress & host, tpport_t port)

set the peer address to send message packets to.

This can be set before every send() call if nessisary.

Parameters:

host

address to send packets to.

port

number to deliver packets to.

MEMBER DATA DOCUMENTATION

struct sockaddr_in UDPSocket::peer [protected]

AUTHOR

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