Bash Script Not Working Bandwidth Shaping - bash

Question

I hope this is an easy answer
Problems:
I placed the following bash script called learn-address.sh in the following folder:
vi /etc/openvpn/netem/learn-address.sh
Added the following (2) lines to the .conf file:
script-security 3
learn-address /etc/openvpn/netem/learn-address.sh
And applied the following permission to the learn-address script:
chmod 755 /etc/openvpn/netem/learn-address.sh
However, the script does update the files ($ip.classid and $ip.dev)
in the tmp file and passes the variables correctly
But the bash script does not execute the tc class and filter commands (there is no change to qdisc)
What permissions would I use on the script to execute the tc class and filter commands when the learn-address script is called when a user connects to OpenVPN or is there something else that I missed?
Many thanks
Name of script: learn-address.sh
#!/bin/bash
statedir=/tmp/
function bwlimit-enable() {
ip=$1
user=$2
dev=eth0
# Disable if already enabled.
bwlimit-disable $ip
# Find unique classid.
if [ -f $statedir/$ip.classid ]; then
# Reuse this IP's classid
classid=`cat $statedir/$ip.classid`
else
if [ -f $statedir/last_classid ]; then
classid=`cat $statedir/last_classid`
classid=$((classid+1))
else
classid=1
fi
echo $classid > $statedir/last_classid
fi
# Find this user's bandwidth limit
# downrate: from VPN server to the client
# uprate: from client to the VPN server
if [ "$user" == "myuser" ]; then
downrate=10mbit
uprate=10mbit
elif [ "$user" == "anotheruser"]; then
downrate=2mbit
uprate=2mbit
else
downrate=5mbit
uprate=5mbit
fi
# Limit traffic from VPN server to client
tc class add dev $dev parent 1: classid 1:$classid htb rate $downrate
tc filter add dev $dev protocol all parent 1:0 prio 1 u32 match ip dst $ip/32 flowid 1:$classid
# Limit traffic from client to VPN server
tc filter add dev $dev parent ffff: protocol all prio 1 u32 match ip src $ip/32 police rate $uprate burst 80k drop flowid :$classid
# Store classid and dev for further use.
echo $classid > $statedir/$ip.classid
echo $dev > $statedir/$ip.dev
}
function bwlimit-disable() {
ip=$1
if [ ! -f $statedir/$ip.classid ]; then
return
fi
if [ ! -f $statedir/$ip.dev ]; then
return
fi
classid=`cat $statedir/$ip.classid`
dev=`cat $statedir/$ip.dev`
tc filter del dev $dev protocol all parent 1:0 prio 1 u32 match ip dst $ip/32
tc class del dev $dev classid 1:$classid
tc filter del dev $dev parent ffff: protocol all prio 1 u32 match ip src $ip/32
# Remove .dev but keep .classid so it can be reused.
rm $statedir/$ip.dev
}
# Make sure queueing discipline is enabled.
tc qdisc add dev $dev root handle 1: htb 2>/dev/null || /bin/true
tc qdisc add dev $dev handle ffff: ingress 2>/dev/null || /bin/true
case "$1" in
add|update)
bwlimit-enable $2 $3
;;
delete)
bwlimit-disable $2
;;
*)
echo "$0: unknown operation [$1]" >&2
exit 1
;;
esac
exit 0

Answer 1

The calls to tc here are occurring before dev is defined, which happens later after you've parsed the function arguments and either called bwlimit-enable or bwlimit-disable. It looks like you want to move those two calls:
# Make sure queueing discipline is enabled.
tc qdisc add dev $dev root handle 1: htb 2>/dev/null || /bin/true
tc qdisc add dev $dev handle ffff: ingress 2>/dev/null || /bin/true
... to below the case statement.