.\" $OpenBSD: clnp.4,v 1.6 2000/12/21 21:01:15 aaron Exp $ .\" $NetBSD: clnp.4,v 1.4 1994/11/30 16:22:07 jtc Exp $ .\" .\" Copyright (c) 1990, 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. .\" .\" @(#)clnp.4 8.2 (Berkeley) 4/2/94 .\" .Dd April 2, 1994 .Dt CLNP 4 .Os .Sh NAME .Nm clnp .Nd Connectionless-Mode Network Protocol .Sh SYNOPSIS .Fd #include .Fd #include .Fd #include .Ft int .Fn socket AF_ISO SOCK_RAW 0 .Sh DESCRIPTION CLNP is the connectionless-mode network protocol used by the connectionless-mode network service. This protocol is specified in ISO 8473. It may be accessed through a .Dq raw socket for debugging purposes only. CLNP 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 read 2 or .Xr recv 2 and .Xr write 2 or .Xr send 2 system calls may be used). .Pp Outgoing packets automatically have a CLNP header prepended to them. Incoming packets received by the user contain the full CLNP header. The following .Xr setsockopt options apply to CLNP: .Bl -tag -width CLNPOPT_FLAGS .It Dv CLNPOPT_FLAGS Sets the flags which are passed to clnp when sending a datagram. Valid flags are: .Pp .Bl -tag -width "CLNP_NO_CKSUM" -offset indent -compact .It Dv CLNP_NO_SEG Do not allow segmentation. .It Dv CLNP_NO_ER Suppress ER pdus. .It Dv CLNP_NO_CKSUM Do not generate the CLNP checksum. .El .Pp .It Dv CLNPOPT_OPTS Sets CLNP options. The options must be formatted exactly as specified by ISO 8473, section 7.5. .Dq Options Part. Once an option has been set, it will be sent on all packets until a different option is set. .El .Sh CONGESTION EXPERIENCE BIT Whenever a packet is transmitted, the globally unique quality of service option is added to the packet. The sequencing preferred bit and the low transit delay bit are set in this option. .Pp If a packet is forwarded containing the globally unique quality of service option, and the interface through which the packet will be transmitted has a queue length greater than .Em congest_threshold , then the congestion experienced bit is set in the quality of service option. .Pp The threshold value stored in .Em congest_threshold may be tuned. .Pp When a packet is received with the globally unique quality of service option present, and the congestion experienced bit is set, then the transport congestion control function is called. .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 EADDRNOTAVAIL When an attempt is made to create a socket with a network address for which no network interface exists; .It Bq Er EHOSTUNREACH When trying to send a datagram, but no route to the destination address exists. .It Bq Er EINVAL When specifying unsupported options. .El .Sh SEE ALSO .Xr recv 2 , .Xr send 2 , .Xr iso 4 , .Xr netintro 4 .Sh BUGS Packets are sent with the type code of 0x1d (technically an invalid packet type) for lack of a better way to identify raw CLNP packets. .Pp No more than .Dv MLEN bytes of options can be specified.