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.\" $OpenBSD: eoip.4,v 1.2 2018/06/19 00:41:14 dlg Exp $
.\" $NetBSD: gre.4,v 1.10 1999/12/22 14:55:49 kleink Exp $
.\"
.\" Copyright 1998 (c) The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Heiko W. Rupp <hwr@pilhuhn.de>
.\"
.\" 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.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
.\"
.Dd $Mdocdate: June 19 2018 $
.Dt EOIP 4
.Os
.Sh NAME
.Nm eoip
.Nd MikroTik Ethernet over IP tunnel network device
.Sh SYNOPSIS
.Cd "pseudo-device gre"
.Sh DESCRIPTION
The
.Nm
interface provides tunnelling of Ethernet frames across
IPv4 and IPv6 networks using the
MikroTik Ethernet over IP (EoIP) encapsulation protocol.
.Pp
The protocol is based on the Generic Routing and Encapsulation (GRE)
protocol.
GRE datagrams (IP protocol number 47) consist of a GRE header
and an outer IP header for encapsulating another protocol's datagram.
The GRE header specifies a version and the type of the encapsulated datagram,
allowing for the tunnelling of multiple protocols.
EoIP uses GRE version 1, its own protocol identifier (0x6400)
for Ethernet, and has its own keepalive semantics,
making it distinct from the Ethernet over GRE version 0 protocol
supported by
.Xr egre 4 .
However, it is implemented as part of the same driver providing
.Xr egre 4 .
.Pp
Different tunnels between the same endpoints are distinguished
by a 16-bit tunnel identifier field in the header.
.Pp
All GRE packet processing in the system is allowed or denied by setting the
.Va net.inet.gre.allow
.Xr sysctl 8
variable.
To allow GRE packet processing, set
.Va net.inet.gre.allow
to 1.
.Pp
.Nm
interfaces can be created at runtime using the
.Ic ifconfig eoip Ns Ar N Ic create
command or by setting up a
.Xr hostname.if 5
configuration file for
.Xr netstart 8 .
.Pp
For correct operation, encapsulated traffic must not be routed
over the interface itself.
This can be implemented by adding a distinct or a more specific
route to the tunnel destination than the hosts or networks routed
via the tunnel interface.
Alternatively, the tunnel traffic may be configured in a separate
routing table to the encapsulated traffic.
.Ss Programming Interface
.Nm
interfaces support the following
.Xr ioctl 2
calls for configuring tunnel options:
.Bl -tag -width indent -offset 3n
.It Dv SIOCSLIFPHYADDR Fa "struct if_laddrreq *"
Set the unicast IPv4 or IPv6 addresses for the encapsulating IP packets.
The addresses may only be configured while the interface is down.
.It Dv SIOCGLIFPHYADDR Fa "struct if_laddrreq *"
Get the addresses used for the encapsulating IP packets.
.It Dv SIOCDIFPHYADDR Fa "struct ifreq *"
Clear the addresses used for the encapsulating IP packets.
The addresses may only be cleared while the interface is down.
.It Dv SIOCSVNETID Fa "struct ifreq *"
Configure a virtual network identifier for use as the Tunnel Identifier.
The virtual network identifier may only be configured while the
interface is down.
The Tunnel Identifier is a 16-bit value.
.It Dv SIOCGVNETID Fa "struct ifreq *"
Get the virtual network identifer used in the GRE Key header.
.It Dv SIOCSLIFPHYRTABLE Fa "struct ifreq *"
Set the routing table the tunnel traffic operates in.
The routing table may only be configured while the interface is down.
.It Dv SIOCGLIFPHYRTABLE Fa "struct ifreq *"
Get the routing table the tunnel traffic operates in.
.It Dv SIOCSLIFPHYTTL Fa "struct ifreq *"
Set the Time-To-Live field in IPv4 encapsulation headers, or the
Hop Limit field in IPv6 encapsulation headers.
.It Dv SIOCGLIFPHYTTL Fa "struct ifreq *"
Get the value used in the Time-To-Live field in a IPv4 encapsulation
header or the Hop Limit field in a IPv6 encapsulation header.
.It Dv SIOCSLIFPHYDF Fa "struct ifreq *"
Configure whether the tunnel traffic sent by the interface can be
fragmented or not.
This sets the Don't Fragment (DF) bit on IPv4 packets,
and disables fragmentation of IPv6 packets.
.It Dv SIOCGLIFPHYDF Fa "struct ifreq *"
Get whether the tunnel traffic sent by the interface can be fragmented
or not.
.It Dv SIOCSETKALIVE Fa "struct ifkalivereq *"
Enable the transmission of keepalive packets to detect tunnel failure.
Keepalives may only be configured while the interace is down.
.Pp
Setting the keepalive period or count to 0 disables keepalives on
the tunnel.
.It Dv SIOCGETKALIVE Fa "struct ifkalivereq *"
Get the configuration of keepalive packets.
.El
.Ss Security Considerations
EoIP does not provide any integrated security features.
It should only be deployed on trusted private networks,
or protected with IPsec to add authentication and encryption for
confidentiality.
IPsec is especially recommended when transporting EoIP over the
public internet.
.Pp
The Packet Filter
.Xr pf 4
can be used to filter tunnel traffic with endpoint policies
.Xr pf.conf 5 .
.Pp
The Time-to-Live (TTL) value of a tunnel can be set to 1 or a low
value to restrict the traffic to the local network:
.Bd -literal -offset indent
# ifconfig eoipN tunnelttl 1
.Ed
.Sh EXAMPLES
.Bd -literal
Host X ---- Host A ------------ tunnel ----------- MikroTik D --- Host E
\e /
\e /
+------ Host B ------ Host C ------+
.Ed
.Pp
On Host A
.Pq Ox :
.Bd -literal -offset indent
# route add default B
# ifconfig eoipN create
# ifconfig eoipN tunnel A D
# ifconfig eoipN up
# route add E D
.Ed
.Pp
On Host D (MikroTik):
.Bd -literal -offset indent
[admin@MikroTik] > interface eoip
[admin@MikroTik] /interface eoip> add name="eoipN" \e
\e... local-address=D remote-address=A
[admin@MikroTik] /interface eoip> enable eoipN
.Ed
.Sh SEE ALSO
.Xr egre 4 ,
.Xr inet 4 ,
.Xr ip 4 ,
.Xr netintro 4 ,
.Xr options 4 ,
.Xr hostname.if 5 ,
.Xr protocols 5 ,
.Xr ifconfig 8 ,
.Xr netstart 8 ,
.Xr sysctl 8
.Sh STANDARDS
.Rs
.%A S. Hanks
.%A "T. Li"
.%A D. Farinacci
.%A P. Traina
.%D October 1994
.%R RFC 1701
.%T Generic Routing Encapsulation (GRE)
.Re
.Sh AUTHORS
.An David Gwynne Aq Mt dlg@openbsd.org
|
