rrqnet-ifupdown.sh(8)
=====================
:doctype: manpage
:revdate: {sys:date "+%Y-%m-%d %H:%M:%S"}

NAME
----
rrqnet-ifupdown.sh - script for managing rrqnet virtual cables with
ifup and ifdown

SYNOPSIS
--------
 for HOOKD in down post-down pre-up up ; do
     ln -s /etc/rrqnet/ifupdown.sh /etc/network/if-$HOOKD.d/rrqnet
 done

DESCRIPTION
-----------

*/etc/rrqnet/ifupdown.sh* is a utility script for managing +rrqnet+
virtual cables via +/etc/network/interfaces+ declarations. In normal
use the script is set up as hook script by means of links from all
+/etc/network/if-*.d/rrqnet+ for automatic invocation with the
commands +ifup+ and +ifdown+.

A +rrqnet+ virtual cable uses a +tap+ interface at each cable end
host, and a service process (aptly named +rrqnet+) to tunnel the +tap+
network traffic over UDP. Each +rrqnet+ process acts as a networking
switch that facilitates level 2 connectivity among all its end points
with packet routing according to the destination Ethernet machine
addresses.

This script handles the special purpose "option codes" for the IFACE
blocks that are used for declaring the +rrqnet+ daemon configuration
to for the +tap+ interface for its virtual cabling. I.e., the IFACE
block is made for the tap interface and it includes one or more of
these +rrqnet+ options.

The list of IFACE options for +rrqnet+ are:

*rrqnet_port* [ notap ] _port_::

This IFACE option is required both as way of marking that the
configuration block is for an +rrqnet+ virtual cable +tap+, and to
declare which UDP port the +rrqnet+ daemon should listen on for
incoming cabling. The port number may be preceded by +notap+ to
indcate that this +rrqnet+ should not have an actual tap interface on
the host but rather only serve to interconnect remote connections.

*rrqnet_nice* _nice_::

This IFACE option is used for adjusting the +rrqnet+ process
scheduling priority. Refer the +nice+ man page for full details.

*rrqnet_remote* _remote_::

This IFACE option is used for declaring the remote connection details.
Refer to +rrqnet+ man page for the full specification. Multiple
remotes for a single +rrqnet+ daemon are declared by using multiple
+rrqnet_remote+ lines.

*rrqnet_options* _options_::

This IFACE option is used for declaring any additional +rrqnet+ daemon
settings ([-tpg] [-4] [-B n] [-T n] [-m mcast]). Refer to the +rrqnet+
man page for the full specification.

*rrqnet_log* _level_ _pathname_::

This IFACE option is used for declaring the log level as one of +-v+,
+-vv+ or +-vvv+, and to nominate the log file. If omitted, all the
+rrqnet+ daemon output will be directed to +/dev/null+. If __pathname_
is of the form "facility.priority", then stderr is sent to +syslog+.
Otherwise, stderr is appended to the nominated file.

*rrqnet_bridge* _bridge_::

This IFACE option is only used to make the +tap+ (once created) to be
made a "port" of the nominated preceding +bridge+ interface. The same
things is achieved by including the +tap+ in the +bridge_ports+ list
of the bridge, provided that the +tap+ is created before the bridge.

*rrqnet_dhcp* _method args_::

This IFACE option is used for attaching a DHCP client to the
interface. The +method+ identifies the DHCP client method, and
currently only the +dhclient+ method is defined, which is run as
follows:
+
----
dhclient -pf $PIDFILE $DHCPARGS -lf $LEASES $IFACE
----
+
The given +args+ if non-empty replaces +$DHCPARGS+, which by default
are "-4 -cf /dev/null". Refer to the +dhclient+ man page for details.

EXAMPLES
--------

The following is a configuration example:

----
iface mynet0 inet static
    address 10.0.0.2/24
    broadcast 10.0.0.255
    rrqnet_port 3636
    rrqnet_options -4 -B 10 -T 1
    rrqnet_remote 111.222.333.444:3636=/sec/mynet.key
    rrqnet_log -v /var/log/mynet0.log
----

The above example declares a virtual cable plug for UDP port +3636+
tunneling through host +111.222.333.444+ port +3636+ where the local
+tap+ +mynet0+ has ipv4 address +10.0.0.2+. The +rrqnet_port+ option
marks the IFACE block as an ++rrqnet+ virtual cabling set up which
then is duly handled by +rrqnet-ifupdown.sh+.

The +rrqnet_options+ in the example tells the +rrqnet+ process to use
an ipv4-only socket, 10 packet buffers and a single delivery thread,
in addition to the socket reader threads. The default is to use an
ipv6 socket, 10 bufffers and 5 delivery threads.

NOTES
-----

This script creates the +tap+ interface if needed, and brings it up.
Thereafter, if so configured the +tap+ is added to the +bridge+, and
then the +rrqnet+ virtual cable process is started under a +daemon+
supervision.

Note that the +rrqnet+ virtual cable requires UDP networking for its
tunnel traffic. The tunnel packets will have a UDP header in addition
to the orignal packet, which means that packets grow with some 28/48
(ipv4/6) bytes.


SEE ALSO
--------

*brctl(8)* - ethernet bridge administration

*daemon(1)* - turns other processes into daemons

*dhclient(8)* - Dynamic Host Configuration Protocol Client

*interfaces(5)* - network interface configuration for ifup and ifdown

*rrqnet(8)* - packet tunneling over UDP, multiple channels

AUTHOR
------
Ralph Rönnquist <ralph.ronnquist@gmail.com>
