ISDN - HDLC/PPP

Setting up an HDLC (PPP) link

The following script, invoked as /usr/local/bin/isdn, is used to set up or shut down an auto-dialing PPP link. Use 'isdn -h' for a short explanation of the commandline syntax.

#!/bin/sh
#
# $Id: HDLC.m4,v 1.2 1999/04/26 12:22:53 ed Exp $
#
# This enables/disables an auto-dialing ISDN PPP link.
#
# Steps in setting up an auto-dialing link:
#	Create the interface
#	Start daemon on the interface
#	Configure the interface
#	Set default route to the interface
#	Point the resolver to a valid set of nameservers

SEMAFILE=/tmp/.isdn-status

# Check commandline syntax
#
if [ "$1" = "" ]; then
	/bin/echo
	/bin/echo "ISDN  - Enable/disable auto-dialing ISDN PPP link"
	/bin/echo "Usage : isdn [ on / off ]"
	if [ -e $SEMAFILE ]; then
		/bin/echo "Status: ISDN is ON"
	else
		/bin/echo "Status: ISDN is OFF"
	fi
	exit 0
fi


# Enable PPP link
#
if [ "$1" = "on" ]; then
	echo Switching on the auto-dialing ISDN PPP link...
	/bin/touch $SEMAFILE & >/dev/null

	##################################################################
	# Setup the ISDN part

	# Create interface
	/sbin/isdnctrl addif ippp0
	# Set provider's telephone number
	/sbin/isdnctrl addphone ippp0 out 0402606606
	# Assign the used MSN/EAZ, use a separate one for separate billing
	/sbin/isdnctrl eaz ippp0 402926299
	# Timeout setting
	/sbin/isdnctrl huptimeout ippp0 90
	# This device doesn't accept any connections
	/sbin/isdnctrl secure ippp0 on
	# HDLC as protokol for security layer
	/sbin/isdnctrl l2_prot ippp0 hdlc
	# Handshaking is PPP
	/sbin/isdnctrl encap ippp0 syncppp
	# ippp0 is firmly linked to interface 0
	# (When using several ipppd daemons, for several PPP connections !)
	/sbin/isdnctrl pppbind ippp0 0
	echo

	##################################################################
	# Setup the IPPPD part

	/sbin/ipppd ipcp-accept-local ipcp-accept-remote lock -bsdcomp -vj -vjccomp -detach mru 1524 -proxyarp user Pevoncken /dev/ippp0 &

	# The IP numbers (local pointopoint remote) are dummies,
	# they are replaced by ipppd after connecting.
	/sbin/ifconfig ippp0 -arp 192.168.1.64 pointopoint 194.151.64.2 netmask 255.255.255.0 metric 1 

	# Just serves automated connection creation
	# and after that is overwritten by ipppd
	/sbin/route del default
	/usr/bin/sleep 1
	/sbin/route add default ippp0

	# Set up the resolver configuration for remote use
#	/bin/cp -a /etc/resolv.conf.on /etc/resolv.conf

	echo Done.
	exit 0
fi


# Disable PPP link, wait some, and restore default route
#
if [ "$1" = "off" ]; then
	echo Switching off the auto-dialing ISDN PPP link...
	/bin/rm $SEMAFILE & >/dev/null

	# Reset the resolver configuration for local use
#	/bin/cp -a /etc/resolv.conf.off /etc/resolv.conf
	# Remove the route pointing to the ippp0 device
	/sbin/route del default
	# Shut down the interface
	/sbin/ifconfig ippp0 down
	/bin/kill -SIGTERM /sbin/pidof ipppd` 2> /dev/null
	/usr/bin/sleep 2
	/bin/kill -SIGKILL `/sbin/pidof ipppd` 2> /dev/null
	/usr/bin/sleep 1
	# Delete the interface
	/sbin/isdnctrl delif ippp0
	# Insert a 'local' default route
	/sbin/route add default gw 192.168.1.1 metric 1

	echo Done.
	exit 0
fi


# If we get here, there was no valid commandline option
#
/bin/echo
/bin/echo "Syntax error"
/bin/echo "usage: isdn [ on / off ]"
/bin/echo
exit 0

Furthermore, the script can copy different resolver file versions to /etc/resolv.conf (on and off respectively). I use the 'online version only, so I disabled the copy-operations for now. /etc/resolv.conf.on contains something like this:

search hal.iaehv.nl iaehv.nl
domain iaehv.nl
nameserver 194.151.64.2
nameserver 194.151.65.2
nameserver 131.155.2.3
nameserver 131.155.2.7

domain iaehv.nl

Hint: You can view the status of the interface using /sbin/isdnctrl list ippp0. To remove the entire interface, use /sbin/isdnctrl delif ippp0 (after executing /sbin/ifconfig ippp0 down).

It is possible to poll UUCP using the X75 lines. If you want to use the HDLC lines for UUCP, you must use a TCP dialer for UUCP. Currently, I do not have such a setup.

top	$Id: HDLC.m4,v 1.2 1999/04/26 12:22:53 ed Exp $