If specified, communication with an upstream DeleGate will be tunneled
via the standard input/output of the command.
The tunnel can be made of any kind of channel,
a raw serial line for example,
as long as it provides bi-directional transmission on it.
Possibly it may be the channel to the DeleGate
which will be invoked from inetd at remote host.
Currently, the tunnelType must be "tty7" which means
transmission between DeleGates is done in 7bits stream.
When the type is "tty7", how the TUNNEL is established is described
in the specified SHIO-script file.
See "src/sample.shio" in the distribution package.
The name of a script file must be specified either in absolute path,
or in relative file name which will be retrieved in
LIBPATH.
The upstream DeleGate for TUNNEL must be invoked with
SERVER="tunnel1".
Example: make a tunnel without login dialogue
TUNNEL=tty7:tunnel.shio
[content of tunnel.shio]
o rsh host delegated SERVER=tunnel1\n
i READY\r\n
=
Example: make a tunnel with login dialogue
TUNNEL=tty7:tunnel.shio
[content of tunnel.shio]
o telnet hostname\n
i login:
o username\n
i Password:
o password\n
i %
o delegated SERVER=tunnel1 \n
i READY\r
i \n
=
As shown in above examples, the first line in a SHIO-script file is
expected to be a shell command like "o command\n" to establish a
connection to a remote server.
Another way to establish a connection is putting "c host:port"
on the first line. No shell nor shell command is invoked in this case.
