1.\" Copyright (c) 2014, Kevin Lo. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.Dd October 1, 2014 26.Dt UDPLITE 4 27.Os 28.Sh NAME 29.Nm udplite 30.Nd Lightweight User Datagram Protocol 31.Sh SYNOPSIS 32.In sys/types.h 33.In sys/socket.h 34.In netinet/udplite.h 35.Ft int 36.Fn socket AF_INET SOCK_DGRAM IPPROTO_UDPLITE 37.Sh DESCRIPTION 38The 39.Tn UDP-Lite 40protocol provides a partial checksum which allows 41corrupted packets to be transmitted to the receiving 42application. 43This has advantages for some types of multimedia 44transport that may be able to make use of slightly 45damaged datagrams, rather than having them discarded 46by lower-layer protocols. 47.Pp 48.Tn UDP-Lite 49supports a number of socket options which can be set with 50.Xr setsockopt 2 51and tested with 52.Xr getsockopt 2 : 53.Bl -tag -width ".Dv UDPLITE_SEND_CSCOV" 54.It Dv UDPLITE_SEND_CSCOV 55This option sets the sender checksum coverage. 56A value of zero indicates that all sent packets will have 57full checksum coverage. 58A value of 8 to 65535 limits the checksum coverage of all sent packets 59to the value given. 60.It Dv UDPLITE_RECV_CSCOV 61This option is the receiver-side analogue. 62A value of zero instructs the kernel to drop all received packets 63not having full checksum coverage. 64A value of 8 to 65535 instructs the kernel to drop all received 65packets with a partial checksum coverage smaller than the value specified. 66.El 67.Sh ERRORS 68A socket operation may fail with one of the following errors returned: 69.Bl -tag -width Er 70.It Bq Er EISCONN 71when trying to establish a connection on a socket which 72already has one, or when trying to send a datagram with the destination 73address specified and the socket is already connected; 74.It Bq Er ENOTCONN 75when trying to send a datagram, but 76no destination address is specified, and the socket has not been 77connected; 78.It Bq Er ENOBUFS 79when the system runs out of memory for 80an internal data structure; 81.It Bq Er EADDRINUSE 82when an attempt 83is made to create a socket with a port which has already been 84allocated; 85.It Bq Er EADDRNOTAVAIL 86when an attempt is made to create a 87socket with a network address for which no network interface 88exists. 89.El 90.Sh SEE ALSO 91.Xr getsockopt 2 , 92.Xr recv 2 , 93.Xr send 2 , 94.Xr socket 2 95