is a simple, unreliable datagram protocol which is used
to support the
abstraction for the Internet
sockets are connectionless, and are
normally used with the
calls, though the
call may also be used to fix the destination for future
packets (in which case the
system calls may be used).
address formats are identical to those used by
#include <particular> UDP
provides a port identifier in addition
to the normal Internet address format.
Note that the
space is separate from the
port space (i.e., a
may not be
In addition broadcast
packets may be sent (assuming the underlying network supports
this) by using a reserved
is network interface dependent.
Options at the
transport level may be used with
A socket operation may fail with one of the following errors returned:
Bq Er EISCONN
when trying to establish a connection on a socket which
already has one, or when trying to send a datagram with the destination
address specified and the socket is already connected;
Bq Er ENOTCONN
when trying to send a datagram, but
no destination address is specified, and the socket has not been
Bq Er ENOBUFS
when the system runs out of memory for
an internal data structure;
Bq Er EADDRINUSE
when an attempt
is made to create a socket with a port which has already been
Bq Er EADDRNOTAVAIL
when an attempt is made to create a
socket with a network address for which no network interface
protocol implements a number of variables in the
branch of the
Enable udp checksums (enabled by default).
Maximum outgoing UDP datagram size
Maximum space for incoming UDP datagrams
For all udp datagrams, to ports on which there is no socket
listening, log the connection attempt (disabled by default).
When a datagram is received on a port where there is no socket
listening, do not return an ICMP port unreachable message.
(Disabled by default.