diff options
Diffstat (limited to 'share/man/man4/udp.4')
-rw-r--r-- | share/man/man4/udp.4 | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/share/man/man4/udp.4 b/share/man/man4/udp.4 new file mode 100644 index 000000000000..03d6db2eef20 --- /dev/null +++ b/share/man/man4/udp.4 @@ -0,0 +1,170 @@ +.\" 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 +.\" $FreeBSD$ +.\" +.Dd June 5, 1993 +.Dt UDP 4 +.Os +.Sh NAME +.Nm udp +.Nd Internet User Datagram Protocol +.Sh SYNOPSIS +.In sys/types.h +.In sys/socket.h +.In 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 ERRORS +A socket operation may fail with one of the following errors returned: +.Bl -tag -width Er +.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 has not 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 MIB VARIABLES +The +.Nm +protocol implements a number of variables in the +.Li net.inet +branch of the +.Xr sysctl 3 +MIB. +.Bl -tag -width UDPCTL_RECVSPACEX +.It UDPCTL_CHECKSUM +.Pq udp.checksum +Enable udp checksums (enabled by default). +.It UDPCTL_MAXDGRAM +.Pq udp.maxdgram +Maximum outgoing UDP datagram size +.It UDPCTL_RECVSPACE +.Pq udp.recvspace +Maximum space for incoming UDP datagrams +.It udp.log_in_vain +For all udp datagrams, to ports on which there is no socket +listening, log the connection attempt (disabled by default). +.It udp.blackhole +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. +See +.Xr blackhole 4 . ) +.El +.Sh SEE ALSO +.Xr getsockopt 2 , +.Xr recv 2 , +.Xr send 2 , +.Xr socket 2 , +.Xr blackhole 4 , +.Xr inet 4 , +.Xr intro 4 , +.Xr ip 4 +.Sh HISTORY +The +.Nm +protocol appeared in +.Bx 4.2 . |