ax25rtd with DG2FEF/DG1KJD Linux-AX.25 Kernel NOTES:

- Here is an example ax25rtd.conf file:

ax25-maxroutes 256
ip-maxroutes 256
ip-encaps-dev ipax0

[sp0]
ax25-learn-routes yes
ax25-learn-only-mine yes
ip-adjust-mode no
ip-learn-routes no
arp-add yes

[ipax0]
arp-add yes
ip-learn-routes yes

- ax25-learn-only-mine has to be on for now, since ax25rtd is not able to
  recognize digipeater paths yet when this node is part of it.

- ax25rtd will be replaced as soon as possible by something reasonable, so
  this is only a temporary solution

- ipax0 must be up when ax25rtd is startet

- all other listeners (ax25d et al) must be registrated at this point of
  time, too

- There must be an entry for ipax0 in /etc/axports, here is an example:

ipax0 dg1kjd-10 76800 256 7 IP-encap device

----
   Jens


*****************************************************************
* Please send all comments and suggestions regarding ax25rtd to *
* Klaus Kudielka (klaus.kudielka@ieee.org).                     *
*****************************************************************

Just a quick small README...
This will hopefully go into the man pages ASAP.

Ax25routed
----------

/usr/sbin/ax25rtd

This is a daemon that:

- emulates the ceased "autorouter" of Linux Kernel AX.25
- sets up ARP entries automagically
- may adjust IP routes and encapsulation mode
  (although I really do not recommend to use this feature...)

The "autorouter" is not really an autorouter. It just listens to the AX.25
traffic on your ports and uses this information to setup AX.25 routes. This
can be turned on or off by altering the configuration file
/etc/ax25/ax25rtd.conf.

Ax25routed provides a socket /var/ax25/ax25rtd/control which is used for
runtime maintainance through ax25rtctl or to set up new routes by other
daemons (a Flexnet router, perhaps?)

On startup ax25rtd reads the configuration file and afterwards preloads
the caches from the files /var/ax25/ax25rtd/ax25_route and
/var/ax25/ax25rtd/ip_route. On SIGTERM or ax25rtctl --save it saves the
caches to those files.

ax25rtd.conf
---------------

The file /etc/ax25/ax25rtd.conf is the configuration file for ax25rtd.
The parameters of the options shown here are the default values except the
ones marked with (example)

ax25-maxroutes	256
ip-maxroutes	256

	The maximum size of the three lists / caches. On overflow,
	ax25rtd will substitute the oldest entry with the new one.
[1k2]
	This marks the beginning of per-port definitions. Note that
	you have to use port names as defined in axports(5) here,
	anywhere else you may use the port or the device name.

ax25-learn-routes no

	Set this to "yes", ax25rtd will add the routing information
	for every heard frame (with complete digipeater path) to the
	kernel AX.25 routing table. Note that ax25rtd's internal cache
	will be updated anyway, regardless of this option.

ax25-learn-only-mine no

	If you set it to "yes", only frames that are sent to (1) the
	interface callsign, (2) any of the listeners on this device, or
	(3) the callsigns specified by ax25-more-mycalls will be used
	to update the internal cache and (depending on
	ax25-learn-routes) the kernel routing table.

ax25-add-path db0ach	(example)

	This is useful on DAMA digipeaters. In this case, the DAMA
	master has to be used for _every_ AX.25 connection, thus
	ax25rtd will add this digipeater(s) to every target we learn
	that has no digipeater path (yet). "db0ach" is just an
	example here.

ax25-more-mycalls dl1bke dl1bke-8	(example)

	You can specify more calls as calls here that belong to
	this interface... "dl1bke" and "dl1bke-8" are examples.

ip-learn-routes no

	If set to "yes", ax25rtd will modify the IP routing table if it
	receives an IP frame (directed to us). This is dangerous!

	It should not screw up your routing table, though. Ax25rtd
	recognizes the netmask of the device and will adjust the route
	only if it fits the netmask and the old route points to
	one of the devices ax25rtd knows about (hence an AX.25 device).

	The problems begin if you have more than one port and a user
	is able to hear your outgoing traffic on at least two of them.
	Due to technical reasons ax25rtd adjusts the route _after_ the
	kernel has sent the reply to the received TCP frame already.
	This has technical reasons.

	If the remote does the same both are switching between the two
	ports.

	Don't use this feature unless you know what you are doing.

	It _should_ be safe do enable this on one-port machines, although
	I strongly recommend to set a network route instead, i.e.:

		route add -net 44.0.0.0 scc3

	Note that ax25rtd's internal cache will be updated anyway,
	regardless of this option.

irtt <irtt>

       If ip-learn-routes is enabled this will assign newly added
       routes an initial round trip time (IRTT) for TCP. <irtt>
       is measured in msec, hence

	       irtt 10000

       sets the irtt to 10 seconds. A value of 0 disables this
       feature (default).

ip-adjust-mode no

	If you set this option to "yes" ax25rtd will change the IP
	encapsulation mode according to the last received IP frame.

	The problem with this option is that the kernel AX.25 sends
	a received IP frame to the IP layer regardless if it was
	sent in UI frame encapsulation "mode datagram (dg)" or
	in I frame encaps, hence in an AX.25 connection, "mode virtual
	connect (vc)". The Linux kernel will respond to this frame
	before ax25rtd can adjust the mode. If the remote does the
	same... You get the picture.

	Don't use this feature unless you know what you are doing.

arp-add	no

	This option, if set to "yes", changes the ARP table to the
	source callsign of the received frame. It should be harmless,
	just has the the effect that if it is a new entry, the Linux
	ARP code will send one ARP request before ax25rtd has adjust
	the ARP table. If there was already an existing ARP entry
	for this IP route, one IP datagram will be sent to the old
	address. Not really a problem, I hope.


Ax25rtctl
---------

/usr/sbin/ax25rtctl <option>

This is a program to control ax25rtd. There are several options:

ax25rtctl --add ax25 <callsign> <dev> <time> [digipeater]
ax25rtctl -a ax25 <callsign> <dev> <time> [digipeater]

	Add an entry to the AX.25 routing table. If time is "0"
	this entry will be marked permanent, hence: the daemon will not
	overwrite this route.

ax25rtctl --del ax25 <callsign> <dev>
ax25rtctl -d ax25 <callsign> <dev>

	Remove an entry from the AX.25 routing table.

ax25rtctl --add ip <ip> <dev> <time> <call> <ipmode>
ax25rtctl -a ip <ip> <dev> <time> <call> <ipmode>

	Add an entry to the IP routing table. If time is "0" the
	entry will be marked permanent.

ax25rtctl --del ip <ip>
ax25rtctl -d ip <ip>

	Remove an entry from the IP routing table.

ax25rtctl --list ax25
ax25rtctl -l ax25

	Lists the content of the cache for the AX.25 routing table.

ax25rtctl --list ip
ax25rtctl -l ip

	Lists the content of the cache for the IP routing table.

ax25rtctl --expire <minutes>
ax25rtctl -e <minutes>

	Removes the entries older than <minutes> from the caches and
	the kernel routing tables.

ax25rtctl --save
ax25rtctl -s

	Saves the AX.25 and IP cache to /var/ax25/ax25rtd/ax25_route and
	/var/ax25/ax25rtd/ip_route (or the files specified in
	/etc/ax25/ax25rtd.conf).

ax25rtctl --reload
ax25rtctl -r

	Reloads the config file /etc/ax25/ax25rtd.conf. This will
	*not* affect the caches or the heard list.

ax25rtctl --shutdown
ax25rtctl -q

	Same as 'killall -TERM ax25rtd' ;-)


ax25rtctl --version
ax25rtctl -V

	Guess what...


Note that you can specify either the port name (as defined in
/etc/ax25/axports) or the interface name (shown by ifconfig). If names
conflict (i.e. port scc0 is in fact interface scc3, and vica versa), the
interface name has precedence over the port name.  Example:

   ax25rtctl --add ax25 dl0tha scc3 0 db0pra

is equivalent to

   ax25rtctl --add ax25 dl0tha 9k6 0 dbpra

All commands return port names in their output, though.
With one exception: ax25_route and ip_route use interface names.


/var/ax25/ax25rtd/control
----------------------------

The commands recognized on this socket are:

add ax25 <callsign> <dev> <time> [<digipeater>]
	Add an AX.25 route
add ip   <ip> <dev> <time> <call> <mode>
	Add an IP route & mode

del ax25 <callsign> <dev>
	Remove an AX.25 route from cache an kernel routing table
del ip   <ip>
	Remove an IP route from cache and kernel routing table

list [ax25|ip]
	List cache entries.

reload
	Reload config

save
	Save cache

expire <min>
	Expire cache entries older than <min> minutes

shutdown
	Save caches and exit

version
	Prints the version of the ax25rtd


Note that every command has to end with a '\n', and every line of the
response ends with an '\n' as well. The last line of a cache list
is just a period alone on a line (".\n").
