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14 <h2>Connecting to other Clusters</h2>
19 <address><a href="mailto:djk@tobit.co.uk">Dirk Koopman G1TLH</a></address>
21 <!-- Created: Sun Dec 13 20:25:14 GMT 1998 -->
23 Last modified: Sun Sep 2 22:02:36 BST 2001
25 <p>At the moment, anybody can connect inwards at any time from outside, either by ax25 or by
26 telnet (assuming you have followed the instructions in <a href="install.html">installation</a>
27 instructions. However, in order to connect outwards, you will need to create <em>connect</em> scripts.
29 <p><em>Connect</em> scripts live in the <tt>/spider/connect</tt> directory and are simple ascii scripts
30 that are written using a normal editor. There are a couple of examples in the issue directory.
32 <p>The first example is a simple telnet (TCP/IP) connect to port 7000 of WR3D (this will actually
33 work if you have or make an arrangement to connect to WR3D)[oh, and substitute x1xxx for your real
36 <p>The colouration will be explained later on in this page, you don't have to try to emulate the colours!</p>
39 <span class=cmd>timeout 15</span>
41 <span class=connect>connect telnet wr3d.dxcluster.net 7000</span>
42 <span class=expect>'login'</span> <span class=send>'x1xxx'</span>
43 <span class=cmd>client wr3d telnet</span>
46 <p>If you put the above script in a file called: <tt>/spider/connect/wr3d</tt> then you can leave out
47 line: <span class=cmd>client wr3d telnet</span>.
48 <p>For a connect that requires a login and execution of the programs
49 from a normal shell, do:-</p>
52 <span class=cmd>timeout 15</span>
53 <span class=connect>connect telnet dirkl.tobit.co.uk</span>
54 <span class=expect>'login'</span> <span class=send>'gb7djk'</span>
55 <span class=expect>'word'</span> <span class=send>'gb7djk'</span>
56 <span class=expect>'\$'</span> <span class=send>'cd /spider/perl'</span>
57 # set the line to prevent echoing, leaving this out will
58 # confuse whole networks for hours!
59 <span class=expect>'\$'</span> <span class=send>'stty -echo raw'</span>
60 # tell GB7DJK that you are GB7DJK-1
61 <span class=expect>'\$'</span> <span class=send>'/spider/src/client gb7djk-1 telnet'</span>
62 # tell GB7DJK-1 that it is connected to GB7DJK
63 # you can leave this out if you call this script 'gb7djk'
64 <span class=cmd>client gb7djk telnet</span>
67 <p>An ax25 example (connecting from GB7DJK, to GB7DXM via my local BPQ node and one X1J intermediate node):-
70 <span class=cmd>timeout 60</span>
71 <span class=cmd>abort (Busy|Sorry|Fail)</span>
72 # don't forget to chmod 4775 netrom_call!
73 <span class=connect>connect ax25 /usr/sbin/netrom_call bbs gb7djk-0 g1tlh-0</span>
74 <span class=expect>'Connected'</span> <span class=send>'c np7'</span>
75 <span class=expect>'*** Connect'</span> <span class=send>'c gb7dxm'</span>
76 <span class=expect>'Connect'</span> <span class=send>''</span>
79 <p>The <tt>-0</tt> ssid is important if you want it to work reliably. Obviously if you are
80 using a different ssid then you would use that. You can use the Netrom alias instead if it
81 it is in the machines node table.</p>
83 <p>The line: "<tt><span class=expect>'Connected'</span> <span class=send>''</span></tt>" means: wait for
84 the string <span class=expect>Connected</span> and when that is seen, then move onto the next line
85 <b>without <span class=send>sending</span> anything</b>. The reason you do this (in this case) is to wait
86 for the final "connect" string from the BPQ node that directly connects you to the
87 cluster node itself.</p>
89 <p>An AGW Engine example would be very similar and look like this:-</p>
92 <span class=cmd>timeout 60</span>
93 <span class=cmd>abort (Busy|Sorry|Fail)</span>
94 <span class=connect>connect agw 2 g1tlh</span>
95 <span class=expect>'*** Connect'</span> <span class=send>'c np7'</span>
96 <span class=expect>'Connected'</span> <span class=send>'c gb7dxm'</span>
97 <span class=expect>'Connect'</span> <span class=send>''</span>
100 <p>A connection is started manually by typing in <tt>connect <scriptname></tt> on a sysop enabled
101 <tt>client.pl</tt> session. For example:-</p>
104 G1TLH de GB7DJK 13-Dec-1998 2041Z > connect gb7djk-1
105 connection to GB7DJK-1 started
106 G1TLH de GB7DJK 13-Dec-1998 2043Z >
109 <p>Consider the following specific example, it is located in the file <tt>/spider/connect/gb7djk-1</tt> :-</p>
112 <span class=cmd>timeout 15</span>
113 <span class=connect>connect telnet dirkl.tobit.co.uk</span>
114 <span class=expect>'login'</span> <span class=send>'gb7djk'</span>
115 <span class=expect>'ssword'</span> <span class=send>'gb7djk'</span>
118 <p>You can watch the progress of the connection (if you have <tt>connect</tt>
119 debugging enabled [<tt>set/debug connect</tt>]) on the
120 <tt>cluster.pl</tt> screen and you should see something like this:-</p>
123 <- D G1TLH connect gb7djk-1
124 -> D G1TLH connection to GB7DJK-1 started
125 -> D G1TLH G1TLH de GB7DJK 13-Dec-1998 2046Z >
126 <span class=cmd>timeout set to 15</span>
127 <span class=connect>CONNECT sort: telnet command: dirkl.tobit.co.uk</span>
128 CHAT "login" -> "gb7djk"
130 Red Hat Linux release 5.1 (Manhattan)
131 Kernel 2.0.35 on an i586
133 <span class=expect>received "login: "</span>
134 <span class=send>sent "gb7djk"</span>
135 CHAT "word" -> "gb7djk"
139 <span class=expect>received "Password: "</span>
140 <span class=send>sent "gb7djk"</span>
141 Connected to GB7DJK-1, starting normal protocol
142 <- O GB7DJK-1 telnet
144 GB7DJK-1 channel func state 0 -> init
146 <- D GB7DJK-1 Last login: Sun Dec 13 17:59:56 from dirk1
147 <- D GB7DJK-1 PC38^GB7DJK-1^~
148 <- D GB7DJK-1 PC18^ 1 nodes, 0 local / 1 total users Max users 0 Uptime 0 00:00^5447^~
152 <p>I have coloured the commands in an attempt to make it clear as
153 to what goes on, where and why. Lines that are <span
154 class=cmd>coloured thus</span> are miscellaneous setup
155 commands. Lines that are <span class=connect>this colour</span>
156 are lines that make the initial <span
157 class=connect>connection</span> to the first hop. The things that
158 are <span class=expect>this colour</span> are the strings I am
159 looking for (what I am <span class=expect>"expecting"</span>) and
160 the things that are <span class=send>this colour</span> are the
161 commands I am going to <span class=send>send</span> when I see the
162 "expect" strings in the input.</p>
164 <p>The script starts by setting the timeout to 15 seconds, then starts
165 the connection. It is <b>important</b> to note that, in the case of
166 an ax25 connection (usually) this will be the callsign of the <i>first hop</i> along the
167 route that you are going to take to the destination, so this will be typically the callsign
168 of your local node.</p>
170 <p>You will notice that the script <span class=expect>waits</span>
171 until it sees the left hand string of the pair and <b>only
172 then</b> does it <span class=send>send</span> the string on the
173 right hand side. This is called a <i>State Machine</i>.</p>
175 <p>A <i>state machine</i> "walks" through a conversation (in this
176 case) looking for "<span class=expect>states</span>" (in this case
177 particular strings) and then performs some "<span
178 class=send>action</span>" (usually some kind of connect command
179 for the type of system you are trying to navigate). When one
180 "<span class=expect>state</span>" "fires"
181 (detects the string are looking for), it <span class=send>sends the command</span>
182 associated with that state and then moves onto the next "<span
183 class=expect>state</span>", in our case: the next line.</p>
185 <p><b>PLEASE NOTE</b>: the colouration in the above example is for illustrative purposes
186 only, the debug output is all one colour.</p>
188 <p>The connect scripts consist of lines which start with the
189 following keywords or symbols:-</p>
193 <li><b>#</b> All lines starting with a <b>#</b> are
194 ignored, as are wholly blank lines.
197 <li><b><span class=cmd>timeout</span></b> followed by a number is the number of
198 seconds to wait for a command to complete. If there is no
199 <b><span class=cmd>timeout</span></b> specified in the script then the default is 60
203 <li><b><span class=cmd>abort</span></b> is a regular expression containing one or
204 more strings to look for to abort a connection. This is a perl
205 regular expression and is executed ignoring case.
208 <li><b><span class=connect>connect</span></b> followed by <b>ax25</b>, <b>telnet</b> or <b>agw</b>
209 and some type dependent information.
212 <b>telnet</b> connection, there can be up to two parameters,
213 the first is the ip address or hostname of the computer you
214 wish to connect to and the second is the port number you want
215 to use (this can be left out if it is a normal telnet
218 <p>In the case of an <b>ax25</b> session then this would
219 normally be a call to <tt>/usr/sbin/ax25_call</tt> or
220 <tt>/usr/sbin/netrom_call</tt> as in the example above. It is your
221 responsibility to get your node and other ax25 parameters to
222 work before going down this route!</p>
224 <p>For <b>agw</b> connections you will need a port number (starting
225 from 1) and the callsign of the first "hop" along the way.</p>
227 <li><b>'</b> is the delimiting character for a word or phrase
228 of an <span class=expect>expect</span>/<span
229 class=send>send</span> line. The words/phrases normally come
230 in pairs, but either can be empty. Each line reads input from
231 the connection until it sees the string (or perl regular
233 is contained in the left hand string.
235 <p>When the <span class=expect>left hand string</span> has found what it is <span class=expect>expecting</span> (if
236 it is) then the <span class=send>right hand string</span> is <span class=send>sent</span> to the connection.</p>
238 <p>If the <span class=expect>left hand
239 string</span> is empty then it doesn't read or wait for anything, it
240 simply <span class=send>sends</span> whatever is on the <span class=send>right hand side</span>.</p>
242 <p>All comparisons are done ignoring case.</p>
244 <p>If the <span class=send>right hand string</span> is empty ('') then nothing is <span class=send>sent</span>, the
245 script simply moves onto the next line.</P>
247 <p>This process is repeated for every line of <tt>chat</tt> script.</p>
249 <li><b><span class=cmd>client</span></b> starts the connection, put the arguments
250 you would want here if you were starting the client program
251 manually. You only need this if the script has a different
252 name to the callsign you are trying to connect to (i.e. you
253 have a script called <tt>other</tt> which actually connects to
254 <tt>GB7DJK-1</tt> [instead of a script called
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262 <span class=copy>Copyright © 1998 by Dirk Koopman G1TLH. All Rights Reserved</span><br>
263 <span class=id>$Id$</span>