SSF.OS.UDP
Class udpSocket

java.lang.Object
  |
  +--SSF.OS.UDP.udpSocket

All Implemented Interfaces:

socketAPI

public class udpSocket

extends java.lang.Object

implements socketAPI

The four socket variables: local_ip, remote_ip, local_port, remote_port identify an end2end UDP session, if at least the local_port, remote_ip and remote_port have valid values. Else if only local_port (and optionally local_ip) are valid, while remote_ip = remote_port = -1, this is a local 'listening server' socket.

The socket variables last_remote_ip, last_remote_port, last_local_ip store the source and destination of the last received UDP/IP header if this is a 'listening server socket', and they can be retrieved by the application that opened this socket.

UDP has no flow control, therefore for a UDP socket the write() operation sends nbytes of data (virtual or an object) immediately in a single UDP datagram if nbytes <= max_datagram_size set by DML attribute udpinit.max_datagram_size.

The UDP socket write() Continuation returns immediately after the datagram was passed through a chain of push() (or equivalent) methods to UDP, IP, and NIC; with a success() if the datagram was successfuly placed in the NIC output queue, and with the failure() if the datagram was dropped by either UDP (nbytes > max_datagram_size), or IP (no route to remote_ip), or by NIC (output queue overflow). Thus write() blocks only for zero elapsed simulation time.

However, UDP socket read() blocks until it receives the requested nbytes of virtual bytes. The socket owner may request to read an arbitrary number of virtual bytes (greater than max_datagram_size). SSF.OS.UDP application writers should keep in mind that since UDP is unreliable, the read() might block forever.

Field Summary

ProtocolSession	appsess local application session that created this socket
dataMessage	emptyMsg
int	last_local_ip
int	last_remote_ip
int	last_remote_port
int	local_ip
int	local_port
int	remote_ip
int	remote_port
udpSession	udpsess local UDP session associated with this socket
udpSessionMaster	udpsessMaster

Constructor Summary

udpSocket(ProtocolSession caller, socketMaster sm)
Constructors

Method Summary

void	abort() not supported for udp sockets
void	accept(socketAPI[] new_socket, Continuation caller) not supported for udp sockets
void	bind(int my_ip, int my_port) names a local socket.
void	close(Continuation caller) Close a connection.
void	connect(int dest_ip, int dest_port, Continuation caller) sets remote IP and UDP port number and creates a UDP session so that socket write() may be used to send UDP datagrams - non-blocking.
void	listen(int request_limit) after bind(), create a UDP listening session so that read() may be used.
void	messageBuffer(dataMessage msg)
void	read(byte[] buf, int nbytes, Continuation caller) not supported for udp sockets
void	read(int nbytes, Continuation caller) Read pseudo-data received by the socket.
void	read(java.lang.Object[] obj, int nbytes, Continuation caller) Read a data object received by the socket.
void	write(byte[] buf, int nbytes, Continuation caller) not supported for udp sockets
void	write(int nbytes, Continuation caller) Write simulated pseudo-data to the socket.
void	write(java.lang.Object[] obj, int nbytes, Continuation caller) Write a concrete data object to the socket.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

udpsess

public udpSession udpsess

local UDP session associated with this socket

udpsessMaster

public udpSessionMaster udpsessMaster

appsess

public ProtocolSession appsess

local application session that created this socket

local_ip

public int local_ip

remote_ip

public int remote_ip

local_port

public int local_port

remote_port

public int remote_port

last_remote_ip

public int last_remote_ip

last_local_ip

public int last_local_ip

last_remote_port

public int last_remote_port

emptyMsg

public dataMessage emptyMsg

Constructor Detail

udpSocket

public udpSocket(ProtocolSession caller,
                 socketMaster sm)

Constructors

Method Detail

bind

public void bind(int my_ip,
                 int my_port)

names a local socket. If local_ip = -1, a valid local host interface address will be assigned by SSF.OS.IP to datagrams sent via this socket after a UDP session is created via listen() or connect().

Specified by:

bind in interface socketAPI

Parameters:

my_ip - local IP address

my_port - local port number

listen

public void listen(int request_limit)

after bind(), create a UDP listening session so that read() may be used. request_limit is not implemented.

Specified by:

listen in interface socketAPI

Parameters:

request_limit - For tcpSocket, specifies the maximum number of connection requests pending accept. Ignored by udpSocket.

connect

public void connect(int dest_ip,
                    int dest_port,
                    Continuation caller)
             throws ProtocolException

sets remote IP and UDP port number and creates a UDP session so that socket write() may be used to send UDP datagrams - non-blocking.

Specified by:

connect in interface socketAPI

Parameters:

dest_ip - remote IP address

dest_port - remote port number

caller - user-defined Continuation specifying the actions to be taken when a connection is either successfully established or an error is signalled.

ProtocolException

accept

public void accept(socketAPI[] new_socket,
                   Continuation caller)

not supported for udp sockets

Specified by:

accept in interface socketAPI

Parameters:

new_socket - one-element array that will contain the new connected socket when Continuation returns successfully.

caller - user-defined Continuation specifying the actions to be taken when a connection is either successfully accepted or an error is signalled.

write

public void write(java.lang.Object[] obj,
                  int nbytes,
                  Continuation caller)

Description copied from interface: socketAPI

Write a concrete data object to the socket.

Specified by:

write in interface socketAPI

Parameters:

obj - user-defined array whose first element obj[0] will be sent

nbytes - nominal size (in bytes) of the data object that defines the transmitted payload size

caller - user-defined Continuation specifying the actions to be taken when either nbytes of (virtual) data is successfully written or an error is signalled.

write

public void write(byte[] buf,
                  int nbytes,
                  Continuation caller)

not supported for udp sockets

Specified by:

write in interface socketAPI

Parameters:

nbytes - size of data to be transmitted

caller - user-defined Continuation specifying the actions to be taken when either nbytes of data is successfully written or an error is signalled.

write

public void write(int nbytes,
                  Continuation caller)

Description copied from interface: socketAPI

Write simulated pseudo-data to the socket.

Specified by:

write in interface socketAPI

Parameters:

nbytes - number of bytes of pseudo-data that defines the transmitted payload size

caller - user-defined Continuation specifying the actions to be taken when either nbytes of data is successfully written or an error is signalled.

read

public void read(byte[] buf,
                 int nbytes,
                 Continuation caller)

not supported for udp sockets

Specified by:

read in interface socketAPI

Parameters:

nbytes - expected received data size

caller - user-defined Continuation specifying the actions to be taken when either all data is read successfully or an error is signalled.

abort

public void abort()

not supported for udp sockets

Specified by:

abort in interface socketAPI

read

public void read(java.lang.Object[] obj,
                 int nbytes,
                 Continuation caller)

Description copied from interface: socketAPI

Read a data object received by the socket.

Specified by:

read in interface socketAPI

Parameters:

obj - user-defined array whose first element obj[0] will contain the data object if read is successful

nbytes - expected number of received data bytes

caller - user-defined Continuation specifying the actions to be taken when either all data is read successfully or an error is signalled.

read

public void read(int nbytes,
                 Continuation caller)

Description copied from interface: socketAPI

Read pseudo-data received by the socket.

Specified by:

read in interface socketAPI

Parameters:

nbytes - expected number of bytes of received pseudo-data

caller - user-defined Continuation specifying the actions to be taken when either all data is read successfully or an error is signalled.

close

public void close(Continuation caller)
           throws ProtocolException

Description copied from interface: socketAPI

Close a connection.

Specified by:

close in interface socketAPI

Parameters:

caller - the user defined Continuation class which defines the action should be taken when connection is either successfully closed or an error is signalled.

ProtocolException

messageBuffer

public void messageBuffer(dataMessage msg)