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that this means full checksum coverage for received packets. If an application is willing to accept packets with partial coverage, it is expected to use the socekt option and provice the minimum coverage it accepts. Reviewed by: kevlo MFC after: 3 days
97 lines
3.4 KiB
Groff
97 lines
3.4 KiB
Groff
.\" Copyright (c) 2014, Kevin Lo.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd October 1, 2014
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.Dt UDPLITE 4
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.Os
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.Sh NAME
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.Nm udplite
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.Nd Lightweight User Datagram Protocol
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.Sh SYNOPSIS
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.In sys/types.h
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.In sys/socket.h
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.In netinet/udplite.h
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.Ft int
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.Fn socket AF_INET SOCK_DGRAM IPPROTO_UDPLITE
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.Sh DESCRIPTION
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The
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.Tn UDP-Lite
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protocol provides a partial checksum which allows
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corrupted packets to be transmitted to the receiving
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application.
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This has advantages for some types of multimedia
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transport that may be able to make use of slightly
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damaged datagrams, rather than having them discarded
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by lower-layer protocols.
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.Pp
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.Tn UDP-Lite
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supports a number of socket options which can be set with
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.Xr setsockopt 2
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and tested with
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.Xr getsockopt 2 :
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.Bl -tag -width ".Dv UDPLITE_SEND_CSCOV"
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.It Dv UDPLITE_SEND_CSCOV
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This option sets the sender checksum coverage.
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A value of zero indicates that all sent packets will have
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full checksum coverage.
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A value of 8 to 65535 limits the checksum coverage of all sent packets
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to the value given.
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.It Dv UDPLITE_RECV_CSCOV
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This option is the receiver-side analogue.
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A value of zero instructs the kernel to drop all received packets
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not having full checksum coverage.
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A value of 8 to 65535 instructs the kernel to drop all received
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packets with a partial checksum coverage smaller than the value specified.
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.El
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.Sh ERRORS
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A socket operation may fail with one of the following errors returned:
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.Bl -tag -width Er
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.It Bq Er EISCONN
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when trying to establish a connection on a socket which
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already has one, or when trying to send a datagram with the destination
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address specified and the socket is already connected;
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.It Bq Er ENOTCONN
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when trying to send a datagram, but
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no destination address is specified, and the socket has not been
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connected;
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.It Bq Er ENOBUFS
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when the system runs out of memory for
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an internal data structure;
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.It Bq Er EADDRINUSE
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when an attempt
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is made to create a socket with a port which has already been
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allocated;
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.It Bq Er EADDRNOTAVAIL
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when an attempt is made to create a
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socket with a network address for which no network interface
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exists.
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.El
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.Sh SEE ALSO
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.Xr getsockopt 2 ,
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.Xr recv 2 ,
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.Xr send 2 ,
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.Xr socket 2
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