140 lines
4.1 KiB
Groff
140 lines
4.1 KiB
Groff
.\" Copyright (c) 1983, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)udp.4 8.1 (Berkeley) 6/5/93
|
|
.\" $Id: udp.4,v 1.5 1997/02/22 13:24:51 peter Exp $
|
|
.\"
|
|
.Dd June 5, 1993
|
|
.Dt UDP 4
|
|
.Os BSD 4.2
|
|
.Sh NAME
|
|
.Nm udp
|
|
.Nd Internet User Datagram Protocol
|
|
.Sh SYNOPSIS
|
|
.Fd #include <sys/types.h>
|
|
.Fd #include <sys/socket.h>
|
|
.Fd #include <netinet/in.h>
|
|
.Ft int
|
|
.Fn socket AF_INET SOCK_DGRAM 0
|
|
.Sh DESCRIPTION
|
|
.Tn UDP
|
|
is a simple, unreliable datagram protocol which is used
|
|
to support the
|
|
.Dv SOCK_DGRAM
|
|
abstraction for the Internet
|
|
protocol family.
|
|
.Tn UDP
|
|
sockets are connectionless, and are
|
|
normally used with the
|
|
.Xr sendto 2
|
|
and
|
|
.Xr recvfrom 2
|
|
calls, though the
|
|
.Xr connect 2
|
|
call may also be used to fix the destination for future
|
|
packets (in which case the
|
|
.Xr recv 2
|
|
or
|
|
.Xr read 2
|
|
and
|
|
.Xr send 2
|
|
or
|
|
.Xr write 2
|
|
system calls may be used).
|
|
.Pp
|
|
.Tn UDP
|
|
address formats are identical to those used by
|
|
.Tn TCP .
|
|
In particular
|
|
.Tn UDP
|
|
provides a port identifier in addition
|
|
to the normal Internet address format. Note that the
|
|
.Tn UDP
|
|
port
|
|
space is separate from the
|
|
.Tn TCP
|
|
port space (i.e. a
|
|
.Tn UDP
|
|
port
|
|
may not be
|
|
.Dq connected
|
|
to a
|
|
.Tn TCP
|
|
port). In addition broadcast
|
|
packets may be sent (assuming the underlying network supports
|
|
this) by using a reserved
|
|
.Dq broadcast address ;
|
|
this address
|
|
is network interface dependent.
|
|
.Pp
|
|
Options at the
|
|
.Tn IP
|
|
transport level may be used with
|
|
.Tn UDP ;
|
|
see
|
|
.Xr ip 4 .
|
|
.Sh DIAGNOSTICS
|
|
A socket operation may fail with one of the following errors returned:
|
|
.Bl -tag -width [EADDRNOTAVAIL]
|
|
.It 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;
|
|
.It Bq Er ENOTCONN
|
|
when trying to send a datagram, but
|
|
no destination address is specified, and the socket hasn't been
|
|
connected;
|
|
.It Bq Er ENOBUFS
|
|
when the system runs out of memory for
|
|
an internal data structure;
|
|
.It Bq Er EADDRINUSE
|
|
when an attempt
|
|
is made to create a socket with a port which has already been
|
|
allocated;
|
|
.It Bq Er EADDRNOTAVAIL
|
|
when an attempt is made to create a
|
|
socket with a network address for which no network interface
|
|
exists.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr getsockopt 2 ,
|
|
.Xr recv 2 ,
|
|
.Xr send 2 ,
|
|
.Xr socket 2 ,
|
|
.Xr inet 4 ,
|
|
.Xr intro 4 ,
|
|
.Xr ip 4
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
protocol appeared in
|
|
.Bx 4.2 .
|