174 lines
5.3 KiB
Groff
174 lines
5.3 KiB
Groff
.\" Copyright (c) 1990, 1991 The Regents of the University of California.
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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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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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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.\" from: @(#)clnp.4 6.3 (Berkeley) 7/31/91
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.\" $Id: clnp.4,v 1.2 1993/08/01 07:56:10 mycroft Exp $
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.\"
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.Dd July 31, 1991
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.Dt CLNP 4
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.Os
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.Sh NAME
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.Nm clnp
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.Nd Connectionless-Mode Network Protocol
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.Sh SYNOPSIS
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.Fd #include <sys/socket.h>
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.Fd #include <netargo/iso.h>
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.Fd #include <netargo/clnp.h>
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.Ft int
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.Fn socket AF_ISO SOCK_RAW 0
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.Sh DESCRIPTION
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.Tn CLNP
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is the connectionless-mode network protocol used by the
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connectionless-mode network service. This protocol is specified in
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.Tn ISO
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8473.
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It may be accessed
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through a
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.Dq raw socket
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for debugging purposes only.
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.Tn CLNP
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sockets are connectionless,
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and are normally used with the
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.Xr sendto
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and
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.Xr recvfrom
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calls, though the
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.Xr connect 2
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call may also be used to fix the destination for future
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packets (in which case the
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.Xr read 2
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or
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.Xr recv 2
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and
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.Xr write 2
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or
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.Xr send 2
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system calls may be used).
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.Pp
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Outgoing packets automatically have a
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.Tn CLNP
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header prepended to
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them. Incoming packets received by the user contain the full
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.Tn CLNP
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header.
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The following
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.Xr setsockopt
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options apply to
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.Tn CLNP :
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.Bl -tag -width CLNPOPT_FLAGS
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.It Dv CLNPOPT_FLAGS
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Sets the flags which are passed to clnp when sending a datagram.
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Valid flags are:
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.Pp
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.Bl -tag -width "CLNP_NO_CKSUM" -offset indent -compact
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.It Dv CLNP_NO_SEG
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Do not allow segmentation
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.It Dv CLNP_NO_ER
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Suppress ER pdus
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.It Dv CLNP_NO_CKSUM
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Do not generate the
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.Tn CLNP
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checksum
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.El
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.Pp
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.It Dv CLNPOPT_OPTS
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Sets
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.Tn CLNP
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options. The options must be formatted exactly as specified by
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.Tn ISO
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8473, section 7.5
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.Dq Options Part.
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Once an option has been set, it will
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be sent on all packets until a different option is set.
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.El
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.Sh CONGESTION EXPERIENCE BIT
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Whenever a packet is transmitted, the globally unique quality of
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service option is added to the packet. The sequencing preferred bit and
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the low transit delay bit are set in this option.
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.Pp
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If a packet is forwarded containing the globally unique quality of
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service option, and the interface through which the packet will be
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transmitted has a queue length greater than
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.Em congest_threshold ,
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then the congestion experienced bit is set in the quality of service option.
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.Pp
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The threshold value stored in
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.Em congest_threshold
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may be tuned.
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.Pp
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When a packet is received with the
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globally unique quality of service option present, and the
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congestion experienced bit is set, then the transport congestion
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control function is called.
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.Sh DIAGNOSTICS
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A socket operation may fail with one of the following errors returned:
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.Bl -tag -width [EADDRNOTAVAIL]
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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 hasn't 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 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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.It Bq Er EHOSTUNREACH
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When trying to send a datagram, but no route to the destination
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address exists.
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.It Bq Er EINVAL
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When specifying unsupported options.
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.El
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.Sh SEE ALSO
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.Xr send 2 ,
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.Xr recv 2 ,
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.Xr intro 4 ,
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.Xr iso 4
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.Sh HISTORY
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The
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.Nm
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protocol implementation
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.Ud
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.Sh BUGS
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Packets are sent with the type code of 0x1d (technically an invalid
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packet type) for lack of a better way to identify raw
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.Tn CLNP
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packets.
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.Pp
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No more than
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.Dv MLEN
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bytes of options can be specified.
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