This script can control the state of your ISDN line. It counts

how many scripts/users currently use the ISDN line and uses
"ifconfig down" if noone uses it any more.

Not objected by:	hm

share/examples/isdn/isdnctl

@@ -0,0 +1,111 @@
+#!/bin/sh
+
+# isdnctl
+# Control the ISDN line based on usage
+#
+# This script can control the state of your ISDN line.  It counts
+# how many scripts/users currently use the ISDN line and uses
+# "ifconfig down" if noone uses it any more.
+# I use this script for cronjobs that fetch mail and news and run cvsup.
+# If I'm still using the line, the script won't close the connection,
+# but if not, it saves a lot of phone costs.
+#
+# ----------------------------------------------------------------------------
+# "THE BEER-WARE LICENSE" (Revision 42, (c) Poul-Henning Kamp):
+# Alexander Langer <alex@big.endian.de> wrote this file.  As long as you retain
+# this notice you can do whatever you want with this stuff. If we meet some
+# day, and you think this stuff is worth it, you can buy me a beer in return.
+#
+# Alexander Langer
+# ----------------------------------------------------------------------------
+#
+# $FreeBSD$
+#
+
+
+usage () {
+	echo "Usage: $0 [-i interface] [-f /path/to/users.file] [up|down|show]"
+}
+
+# Defaults
+INTERFACE=isp0
+USERSFILE=
+
+# Getopt stuff
+args=`getopt i:f: $*`
+if [ $? != 0 ]; then
+		usage
+		exit 2
+	fi
+set -- $args
+for i; do
+	case "$i" in
+		-i)
+			INTERFACE="$2"
+			shift; shift
+			;;
+		-f)
+			USERSFILE="$2"
+			shift; shift
+			;;
+		--)
+			shift
+			break
+			;;
+	esac
+done
+
+if [ -z $USERSFILE ]; then
+	USERSFILE=/var/run/isdn.users.$INTERFACE
+fi
+
+if [ -z $1 ]; then
+	usage
+	exit 2
+fi
+
+# Does Usersfile exist?
+if [ ! -f $USERSFILE ]; then
+	# Try to create it
+	if ! /sbin/ifconfig $INTERFACE | grep "^$INTERFACE.*<UP," > /dev/null; then
+		echo "0" > $USERSFILE || exit 1
+	else
+		echo "1" > $USERSFILE || exit 1
+	fi
+elif [ ! -w $USERSFILE ]; then
+	echo "Error: $USERSFILE not writeable!"
+	exit 1
+fi
+
+if ! /sbin/ifconfig $INTERFACE | grep "^$INTERFACE.*<UP," > /dev/null; then
+	if ! cat $USERSFILE | grep '^0$' > /dev/null ; then 
+		echo "Interface down, removing number from file";
+		echo "0" > $USERSFILE
+	fi;
+fi;
+
+case "$1" in
+		show)
+			echo "`cat $USERSFILE` users online"
+			;;
+		up)
+			expr `cat $USERSFILE` + 1 > $USERSFILE
+			/sbin/ifconfig $INTERFACE up
+			echo "`cat $USERSFILE` users online"
+			;;
+		down)
+			if cat $USERSFILE | grep '^0$' > /dev/null ; then 
+				echo "Already down"
+				exit 0
+			fi
+			expr `cat $USERSFILE` - 1 > $USERSFILE
+			if cat $USERSFILE | grep '^0$' > /dev/null ; then 
+				echo "`cat $USERSFILE` users online, interface down"
+				/sbin/ifconfig $INTERFACE down
+				exit 0
+			fi
+			echo "`cat $USERSFILE` users online"
+			;;
+esac
+
+exit 0