mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-12-26 13:05:18 +01:00
1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
217 lines
6.4 KiB
Groff
217 lines
6.4 KiB
Groff
.\" 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.
|
|
.\"
|
|
.\" @(#)esis.4 8.2 (Berkeley) 11/30/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd November 30, 1993
|
|
.Dt ESIS 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm esis
|
|
.Nd End System to Intermediate System Routing Protocol
|
|
.Sh SYNOPSIS
|
|
.Sy pseudo-device
|
|
.Nm ether
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm ES-IS
|
|
routing protocol is used to dynamically map between
|
|
.Tn ISO NSAP
|
|
addresses and
|
|
.Tn ISO SNPA
|
|
addresses; to permit End and Intermediate Systems
|
|
to learn of each other's existence; and to allow Intermediate Systems
|
|
to inform End Systems of (potentially) better routes to use when
|
|
forwarding
|
|
.Tn NPDU Ns s
|
|
to a particular destination.
|
|
.Pp
|
|
The mapping between
|
|
.Tn NSAP
|
|
addresses and
|
|
.Tn SNPA
|
|
addresses is accomplished by
|
|
transmitting hello
|
|
.Tn PDU Ns s
|
|
between the cooperating Systems. These
|
|
.Tn PDU Ns s
|
|
are transmitted whenever the
|
|
.Em configuration
|
|
timer expires.
|
|
When a hello
|
|
.Tn PDU
|
|
is received, the
|
|
.Tn SNPA
|
|
address that it conveys is stored in the routing table for as long as the
|
|
.Em holding time
|
|
in the
|
|
.Tn PDU
|
|
suggests. The default
|
|
.Em holding time
|
|
(120 seconds) placed in the hello
|
|
.Tn PDU ,
|
|
the configuration timer value,
|
|
and the system type (End System or Intermediate System) may be changed by
|
|
issuing an
|
|
.Dv SIOCSSTYPE
|
|
.Xr ioctl 2 ,
|
|
which is defined in
|
|
.Pa /sys/netiso/iso_snpac.h.
|
|
.Pp
|
|
The protocol behaves differently depending on whether the System is
|
|
configured as an End System or an Intermediate System.
|
|
.Sh END SYSTEM OPERATION
|
|
When an interface requests a mapping for an address not in the cache,
|
|
the
|
|
.Tn SNPA
|
|
of any known Intermediate System is returned. If an Intermediate
|
|
System is not known, then the
|
|
.Em all end systems
|
|
multicast address
|
|
is returned. It is assumed that the intended recipient of the NPDU will
|
|
immediately transmit a hello
|
|
.Tn PDU
|
|
back to the originator of the
|
|
.Tn NPDU .
|
|
.Pp
|
|
If an
|
|
.Tn NPDU
|
|
is forwarded by the End System, a redirect
|
|
.Tn PDU
|
|
will not be
|
|
generated.
|
|
However, redirect
|
|
.Tn PDU Ns s
|
|
received will be processed. This processing
|
|
consists of adding an entry in the routing table. If the
|
|
redirect is towards an Intermediate System, then an entry is made in the
|
|
routing table as well.
|
|
The entry in the routing table will mark the
|
|
.Tn NSAP
|
|
address contained in the redirect
|
|
.Tn PDU
|
|
as the gateway for the destination
|
|
system (if an NET is supplied), or will create a route with
|
|
the NSAP address as the
|
|
destination and the
|
|
.Tn SNPA
|
|
address (embodied as a link-level sockaddr) as the
|
|
gateway.
|
|
.Pp
|
|
If the System is configured as an End System, it will report all the
|
|
.Tn NSAP Ns s
|
|
that have been configured using the ifconfig command, and no others.
|
|
It is possible to have more than one
|
|
.Tn NSAP
|
|
assigned to a given interface,
|
|
and it is also possible to have the same
|
|
.Tn NSAP
|
|
assigned to multiple
|
|
interfaces.
|
|
However, any
|
|
.Tn NSAP
|
|
containing an NSEL that is consistent with the
|
|
nsellength option (default one) of any interface will be accepted as
|
|
an
|
|
.Tn NSAP
|
|
for this System.
|
|
.Sh INTERMEDIATE SYSTEM OPERATION
|
|
When an interface requests a mapping for an address not in the routing table,
|
|
an error is returned.
|
|
.Pp
|
|
When an
|
|
.Tn NPDU
|
|
is forwarded out on the same interface that the
|
|
.Tn NPDU
|
|
arrived upon,
|
|
a redirect
|
|
.Tn PDU
|
|
is generated.
|
|
.Sh MANUAL ROUTING TABLE MODIFICATION
|
|
.Pp
|
|
To facilitate communications with systems which do not use
|
|
.Nm ES-IS,
|
|
one may add a route whose destination is a sockaddr_iso containing
|
|
the
|
|
.Tn NSAP
|
|
in question, and the gateway being a link-level sockaddr,
|
|
either by writing a special purpose program, or using the
|
|
.Xr route 8
|
|
command e.g.:
|
|
.Bd -literal
|
|
route add -iface -osi 49.0.4.8.0.2b.b.83.bf \
|
|
-link qe0:8.0.2b.b.83.bf
|
|
.Ed
|
|
.Pp
|
|
If the
|
|
System is configured as an End System and has a single network interface
|
|
which does not support multicast reception,
|
|
it is necessary to manually configure the location of an
|
|
.Tn IS ,
|
|
using the route command in a similar way.
|
|
There, the destination address should be
|
|
.Dq default
|
|
(spelled
|
|
out literally as 7
|
|
.Tn ASCII
|
|
characters), and the gateway should be
|
|
once again be a link-level sockaddr specifying the
|
|
.Tn SNPA
|
|
of the
|
|
.Tn IS .
|
|
.Sh SEE ALSO
|
|
.Xr iso 4 ,
|
|
.Xr un 4 ,
|
|
.Xr ifconfig 8 ,
|
|
.Xr route 8
|
|
.Rs
|
|
.%T "End system to Intermediate system routing exchange protocol for use in conjunction with the Protocol for providing the connectionless-mode network service"
|
|
.%R ISO
|
|
.%N 9542
|
|
.Re
|
|
.Sh BUGS
|
|
Redirect
|
|
.Tn PDU Ns s
|
|
do not contain options from the forwarded
|
|
.Tn NPDU
|
|
which generated
|
|
the redirect. The multicast address used on the 802.3 network is taken from
|
|
the
|
|
.Tn NBS
|
|
December 1987 agreements. This multicast address is not compatible
|
|
with the 802.5 (Token Ring) multicast addresses format. Therefore, broadcast
|
|
addresses are used on the 802.5 subnetwork.
|
|
Researchers at the University of Wisconsin are constructing an implementation
|
|
of the
|
|
.Tn IS-IS
|
|
routing protocol.
|