DECnet on Ubuntu - Setup

Here I describe how to connect two virtual Ubuntu 9.10 installations over DECnet.

Since I do not have two PC’s running Ubuntu, I use virtual installations running under VMWare Workstation. But this should not make any difference to physical Ubuntu-computers.

Using virtual installations has the advantage that you easily can clone one installation to get another network member. So backup your Ubuntu base installation BEFORE you install DECnet onto it, and later use the clone to setup a second system.

Installation

DECnet has always been part of Debian, but nowadays it’s not installed by default anymore. Here is some documentation.

Under UBUNTU, use the “Synaptic Package Manager” and install the packages “dnet-common” and “dnet-progs”. You will be asked for a node name and a node address.

DECnet addressing and MAC-ID

Under “DECnet Phase IV”, a computer (node) address in the network is given in the form "area.node", with area 1..63 and node 1..1023. Here I choosed the address “2.10”. A computer is also identified by a six-letter name, I use “linux1” in this example.

Setting a DECnet address changes the MAC-ID of your network card. Here is a MAC-ID calculator. So before installation, “ifconfig” shows something like

eth0     Link encap:Ethernet  Hardware Adresse 00:0c:29:ef:18:55
 inet Adresse:192.168.1.187 Bcast:192.168.1.255  Maske:255.255.255.0

and after installation, this changes to

eth0     Link encap:Ethernet  Hardware Adresse aa:00:04:00:0a:08 
 inet Adresse:192.168.1.196 Bcast:192.168.1.255  Maske:255.255.255.0

Attention: To force the new MAC-ID, I had also to edit /etc/network/interfaces (as described here):

$ sudo gedit /etc/network/interfaces

Add the two lines beginning with “iface”

auto eth0 
 iface eth0 inet dhcp
 hwaddress ether AA:00:04:00:0A:08

Then execute:

$ sudo /etc/init.d/networking restart

Twiddling with the MAC-ID maybe confuse your network router, so Reboot!

Setting up a 2nd Ubuntu.

To test this setup, we need a second node in the DECnet. Use a copy of your original Ubuntu installation. Give the copy another hostname! I called this node “linux2”, and gave it a DECnet address of “2.11”, so it’s MAC-id is AA:00:04:00:0B:08.

DECnet setup

DECnet is configured with three configuration files, each must be edited on both Ubuntu installations. They are pretty simple and self-explanatory

1) “/etc/decnet.conf” is like “/etc/hosts” for TCP/IP. It lists all nodes in the network and specifes the “localhost”

Here is /etc/decnet.conf on node “linux1”. It lists the other Ubuntu “linux” and a two nodes “simvax” and “vx3200”, wich we will add later.

#
 # DECnet hosts file 
 #
 #Node      Node     Name     Node        Line   Line 
 #Type      Address  Tag      Name        Tag    Device 
 #-----     -------  -----    -------   -----     ---- 
 executor   2.10     name     linux1  line       eth0 
 node       2.11     name     linux2 
 node       2.20     name     simvax 
 node       2.21     name     vx3200

And here the same for node “linux2”. Now “linux2” is “executor” and “linux1” is just a normal node.

#
 # DECnet hosts file 
 #
 #Node      Node     Name     Node        Line   Line 
 #Type      Address  Tag      Name        Tag    Device 
 #-----     -------  -----    -------   -----     ---- 
 executor   2.11     name     linux2  line       eth0 
 node       2.10     name     linux1 
 node       2.20     name     simvax 
 node       2.21     name     vx3200

All users must read decnet.conf:

# chmod a+r /etc/decnet.conf

2) “/etc/decnet.proxy” . This file controls access to the local machine and maps remote users to local users. Here it is for both “linux1” and “linux2”:

#     /etc/decnet.proxy
 #
 # DECnet proxy database.
 # The format of this file is (one entry per line) 
 # node::remoteuser localuser
 #
 # ... 
 #
 # ^tramp$::^test$ chrissie # Explicitly convert 'test' on tramp to chrissie     
 # ^zaphod$::.*   none     # Disable proxies from zaphod 
 .*::.* */DEFAULT
 # associate all remote users with a
 # similarly named user on the local VMS machine 
 
 #                              #   a user called 'none') 
 # .*::.* decnet            # Like a default     DECnet account 
 # .*::.* *                 #     Equivalent to VMS *::* * proxy (make this last 
 #                              #   if you use it)

I added only the rule: “.*::.* */DEFAULT”. This means, that each remote user is authenticated by his remote username and password. So if a user has an identical account on local host and remote host, everything is fine and there is no need to give user name and password for each command (see below).

3) “/etc/dnet.conf” specifies services (“objects”) for remote users. It’s like the old “/etc/inetd.conf” for TCP/IP. The default configuration is fine:

# /etc/dnetd.conf 
 #
 # Define DECnet objects
 #
 # Fields
 # name:    object name (or * for any named object, number must be     0) 
 # number:  object number (or 0 for a named object) 
 # options: auth[,auto accept]:
 #  auth:        Whether to authenticate users: Y     or N 
 #  auto accept: Should we accept incoming connections 
 #                This is needed for     non-decnet daemons 
 #                (not calling     dnet_accept) 
 # user:    If auth is N then use this user 
 # daemon:  program to run or 'internal' 
 #
 # name         number    options  user           daemon 
 #
 FAL            17            Y,N      none       fal 
 MIRROR         25        Y,N          root     internal 
 MAIL           27            N,N      vmsmail    vmsmaild 
 CTERM          42            N,N      root       ctermd 
 DTERM          23            N,N      root       rmtermd 
 NML            19            N,N      nobody     dnetnml 
 *              *            Y,R      none       internal

“FAL” is the “File Access Listener”, the service for remote file access. “CTERM” and “DTERM” are two flavours of remote login. “MIRROR” is used for DECnet-Ping.

DECnet on Ubuntu - Tools

Now we will use the DECnet installation. Make sure both Ubuntu installation ("linux1" and "linux2") are up and running on the same network - be it physical or virtual.
For all examples, I will work on "linux1" and contact "linux2" over network. My username and my password are both "joerg".
There are "man" pages for each command below!

"dneigh" - Show other nodes on the net

The command "dneigh" shows other nodes on the same DECnet.

joerg@linux1:~$ dneigh
linux2                   ether   AA:00:04:00:0B:08   ---        1498       eth0
linux1                   loop    AA:00:04:00:0A:08   ---        16434      lo
joerg@linux1:~$

Attention: in my tests, I found that "dneigh" shows other nodes only after other applications like "phone" where run.

"dnping" - test "MIRROR" object on remote node.

dnping is not as low-level as TCP/IP ping. It needs an active service on the remote host, and you must also authenticate on the remote host with username and password.

joerg@linux1:~$ dnping linux2 -u joerg -p joerg
Sent 10 packets, Received 10 packets

If something is wrong, the error is "socket: Connection refused.

"phone" - chat with other user

This is pretty cool ... at least it was so in the '80s! You can see who's logged on, and can "ring" him to talk with you over a graphical application.
1) Start phone utiltiy:

joerg@linux1:~$phone

(Inside phone, all commands start with "%".)
2) see, who is logged on:

%dir linux2

3) Ring him:

%dial linux2::joerg

4) on the other side, see it "ringing". No matter what you do, your terminal display is every 10 seconds disturbed by the message

LINUX1::JOERG is phoning you on LINUX2::     (17:12:20)

5) on the other node, answer the call :

joerg@linux2:~$phone
%answer

Now type text, it appears directly in your panel of the "phone" screen on both local and remote host.
6) Hang up
Type

%quit

"sethost" - remote login

This is like "telnet". See me logging on from linux1 to linux2:

joerg@linux1:~$ sethost linux2
sethost V1.0.4
Connecting to linux2
Cterm connection. Escape Sequence  is ^]

CTERM Version 1.0.6
DECnet for Linux

linux2 login: joerg
Password:

Last login: Sat Mar 20 19:51:25 CET 2010 on pts/1
Linux linux2 2.6.31-14-generic #48-Ubuntu SMP Fri Oct 16 14:04:26 UTC 2009 i686

To access official Ubuntu documentation, please visit:
http://help.ubuntu.com/

0 packages can be updated.
0 updates are security updates.

joerg@linux2:~$

"dndir" - show directory on remote node

This is the first file related command I expercise, so things are getting more VMS-like now.
All file-related DECnet commands use OpenVMS syntax for files and directories. Even if both local and remote nodes are Linuxes, the remote node is always accessed as if it would using OpenVMS.
The OpenVMS file path syntax is quite different from UNIX path logic. The generic form for VMS-file names is

node::device:[rootdir.subdir.subdir...]file.ext;version

Most parts of the path are optional.
I have an Eclipse-Installation in "/usr/joerg/eclipse" on "linux2". To list its installation directory, type

joerg@linux1:~$ dndir linux2::[home.joerg.eclipse]*.*

and get:

Directory of HOME:[JOERG.ECLIPSE]
ABOUT.HTML;1      ABOUT_FILES.DIR;1 ARTIFACTS.XML;1   CONFIGURATION.DIR;1
DROPINS.DIR;1     ECLIPSE.;1        ECLIPSE.INI;1     EPL-V10.HTML;1
FEATURES.DIR;1    ICON.XPM;1        LIBCAIRO-SWT.SO;1 NOTICE.HTML;1
P2.DIR;1          PLUGINS.DIR;1     README.DIR;1

You see:

• VMS file names are NOT case-sensitive. Filenames are ALWAYS mapped to uppercase, even if this generates duplicate filenames on the remote Linux node.

• Subdirectories are listed as normal files, with a ".DIR" extension.

• the VMS version number is always "1" for Linux nodes.

• "/home" can also be accessed as device "HOME:"

You wonder about missing authentication? No log-in on the remote "linux2" is required here because

• we have the rule ".*::.* */DEFAULT" in "/etc/dnet-proxy"

• AND we have user "joerg" with password "joerg" on both "linux1" and "linux2".

Normally you must give username and password (for the remote node!) as part of the remote node name. So

node

 becomes

node ”username password”

and the generic filename path is now

node”username password”::device:[rootdir.subdir,subdir...]file.ext;version

Whoa! To squeeze all this through the Unix-shell parameter expansion, better surround the whole stuff with single quotes:

joerg@linux1:~$ dndir 'linux2"joerg joerg"::home:[joerg.eclipse]*.*'

"dncopy" - Copy files over DECnet

This is why we're dealing with DECnet!
After managing "dndir", using "dncopy" is easy. The dncopy-Command has the usual syntax

dncopy options sourcefile targetfile

or

dncopy options sourcefile targetdirectory

Both source and target can reside on any machine, so you can work on a DECnet node “linux1” and copy files from ”linux2” to ”linux3”.

Here I generate a dummy-textfile “test.out” and copy it from “linux1:/home/joerg” to “linux2:/home/joerg”

joerg@linux1:~$ ls -l >test.out
joerg@linux1:~$ ls -l *.out
-rw-r--r-- 1 joerg joerg 1308 2010-03-25 10:55 test.out

joerg@linux1:~$ dncopy -s test.out 'linux2"joerg joerg"::home:[joerg]'
Sent 1308 bytes in 0.00 seconds:  infK/s

joerg@linux1:~$ dndir -l 'linux2"joerg joerg"::home:[joerg]*.out'

Directory of HOME:[JOERG]

TEST.OUT;1             1308 25-MAR-2010 10:55:57 [1750,1750] (RWED,RWD,R,R)

Be aware of file types: VMS files sometimes have an internal block structure, they are not just a stream of bytes.
At least VMS-executables (with .EXE-Extension) must be copied with the “-mblock” Option. And other binary files, as backup-dumps, too.
Read “man dncopy” and try experimenting with “-mrecord”,” -mblock” and “-b” options.

Other commands

There are still more DECnet commands. See the man pages of

• dntype,
• dndel,
• dntask,
• dnsubmit
• and dnprint.

DECnet on a VAX

Using DECnet under VMS is of course much easier then using it under Linux. But you have to deal with that vintage VMS/VAX stuff. VMS is a very rich and comfortable operating system, but some of its concepts are now rather unfamiliar.

This tutorial is valid for simulated and physical VAXes.

The simulated VAX becomes node address 2.20, and is named “SIMVAX”.
The physical VAX 3200 is node 2.21 and is named “VX3200”.

Setup a VAX emulation with SimH

Before trashing the physical VAX, I setup a SimH-Simulation.

Explaining SimH is far beyond the scope of this tutorial.

Here is the startup file:

; uvax.vaxsim
 ;
 ; See also: http://www.wherry.com/gadgets/retrocomputing/vax-simh.html 
 
 ; simulates my uVAX, 3200 (label on box says "uVAX II/GPX") 
 load -r ../../../emulation/simh/ka655x.bin 
 ; I have 2x 8MB
 set cpu 16m
 
 ; save NVR in file
 attach nvr nvram.bin
 
 ; I have aTK50
 set TQ0 enable
 set TQ0 WRITEENABLE
 set TQ TK50
 set TQ1 disable
 set TQ2 disable
 set TQ3 disable
 
 sh tq
 sh tq0
 
 
 ; I have one RD54
 set RQ0 enable
 set RQ0 writeenable
 set RQ0 RD54
 set RQ1 disable
 set RQ2 disable
 set RQ3 cdrom
 
 attach RQ0 vms5.2-1.durd_54 
 attach RQ3 ../../../os/openvms/openvms-vax-7.3.iso 
 
 
 sh rq
 sh rq0
 
 ; no rl01/02 
 set rl disable
 
 ; Network on UBUNTU 
 set xq enabled
 set xq
 ; MAC-ID for DECnet addr 2.20
 set xq mac=AA-00-04-00-14-08
 attach xq0 eth0 
 sh xq
 
 echo
 echo ### Booting VAX CPU ....
 echo ###
 echo ### After the >>> prompt enter: 
 echo ### >>> b dua0 /r5:1
 echo ###
 
 set console telnet=23
 boot cpu

You see that the network card’s MAC-ID is already defined by a DECnet node address. The VAX gets DECnet node address “2.20”, so the MAC-ID is AA-00-04-00-14-08.

I let this simulation run on an Ubuntu host, here “linux1”:

Attention: Due to limitations of SimH’s network drivers, the simulated VAX can not connect to the machine it is running on. So if the simulated VAX “SIMVAX” runs onUbuntu installation “linux1”, there will be no network connection between SIMVAX and linux1. All other connection (SIMVAX - linux2, linux1 - linux2, etc) will work well.!

You start the simulated vax by running something like

$ sudo ~/simh/vax uvax.vaxsim

Then you have to start a VT100-emulation and connect it over telnet to SimH’s host machine. The simulated VAX will then start running.

Setup a physical VAX

On the physical VAX, no MAC-ID setup is necessary. But you have to connect it to your network.

>>>boot DUA0:

$ run sys$system:ncp
 NCP> set executor state off

$ @sys$manager:netconfig

        DECnet-VAX network configuration procedure 

 This procedure will help you define the parameters needed to get DECnet 
 running on this machine. You will be shown the changes before they are 
 executed, in case you wish to perform them manually.

 What do you want your DECnet node name to be?          [oldnam]: simvax 
 What do you want your DECnet address to be?                  : 2.20 
 Do you want to operate as a router?        [NO (nonrouting)]: 
 Do you want a default DECnet account?                    [NO]: yes 
 Do you want default access to the TASK object disabled? [YES]: no 
 Do you want a default account for the MAIL object?     [YES]: 
 Do you want a default account for the FAL object?        [NO]: yes 
 Do you want a default account for the PHONE object?    [YES]: 
 Do you want a default account for the NML object?      [YES]: 

$ run sys$system:ncp
 NCP> clear node *
 NCP> purge node *
 NCP> exit

 $ run sys$system:ncp
 NCP>define node 2.10 name linux1
 NCP>define node 2.11 name linux2
 NCP>define node 2.21 name vx3200
 NCP>set known nodes all
 NCP>show node *

 Known Node Volatile Summary as of 21-MAR-1999 15:45:26

 Executor node = 2.20 (SIMVAX)

 State                    = on 
 Identification           = SIMHVAX 

 Node           State     Active Delay  Circuit    Next node 
                            Links 
 2.10 (LINUX1)                               QNA-0          0 
 2.11 (LINUX2)                               QNA-0          0 
 2.21 (VX3200)                               QNA-0          0

 “NCP>define node ...” 

$ dir linux2"joerg joerg"::[home.joerg.eclipse]

 Directory LINUX2"joerg password"::HOME:[JOERG.ECLIPSE] 

 ABOUT.HTML;1     ABOUT_FILES.DIR;1 ARTIFACTS.XML;1  CONFIGURATION.DIR;1 
 DROPINS.DIR;1    ECLIPSE.;1       ECLIPSE.INI;1    EPL-V10.HTML;1   
 FEATURES.DIR;1   ICON.XPM;1       LIBCAIRO-SWT.SO;1 NOTICE.HTML;1    
 P2.DIR;1         PLUGINS.DIR;1    README.DIR;1