osx network emulator with dummynet

dummynet.sh

#!/bin/bash

# ./dummynet.sh -b 500 -q 1000 -i 1 -t out -f 10.22.133.53 prepare
# ./dummynet.sh -b 500 -q 1000 -i 2 -t out -f 10.22.133.25 prepare
# ./dummynet.sh start
# ./dummynet.sh stop

#
# To avoid sudo with password, adding the following into /etc/sudoers
#
#  yourusername ALL=(ALL)       NOPASSWD: /sbin/pfctl
#  yourusername ALL=(ALL)       NOPASSWD: /usr/sbin/dnctl
#

FILTER_IP="any"

PIPE_IDX="1"

# kbit
LINK_BW="8000"

RAND_LOSS="0.00"

# ms
DELAY=1

# ms
QDELAY=100

DIRECTION="out"

PROTO="udp"

OPTIONS=i:,b:,l:,d:,q:,f:,t:,p:
PARSED=$(getopt $OPTIONS $*)
if [ $? -ne 0 ]; then
    exit 2
fi

eval set -- "$PARSED"

while true; do
    case "$1" in
        -i)
            PIPE_IDX=$2
            shift 2
            ;;
        -b)
            LINK_BW=$2
            shift 2
            ;;
        -l)
            RAND_LOSS=$2
            shift 2
            ;;
        -d)
            DELAY=$2
            shift 2
            ;;
        -q)
            QDELAY=$2
            shift 2
            ;;
        -f)
            FILTER_IP=$2
            shift 2
            ;;
        -t)
            DIRECTION=$2
            shift 2
            ;;
	-p)
	    PROTO=$2
	    shift 2
	    ;;
        --)
            shift
            break
            ;;
        *)
            echo "option not found!"
            exit 3
            ;;
    esac
done

TB_QSIZE=`expr $LINK_BW \* $QDELAY / 8000` # KB

prepare()
{
    sudo dnctl pipe $PIPE_IDX config plr $RAND_LOSS bw "$LINK_BW"Kbit/s delay $DELAY queue "$TB_QSIZE"KB

    if [ "$DIRECTION" = "out" ]; then
        echo "dummynet out proto $PROTO from any to $FILTER_IP pipe $PIPE_IDX" >> /tmp/dummynet
    elif [ "$DIRECTION" = "in" ]; then
        echo "dummynet in proto $PROTO from $FILTER_IP to any pipe $PIPE_IDX"  >> /tmp/dummynet
    else
        echo "wrong direction: $DIRECTION"  
    fi;
}

start()
{
    sudo pfctl -f /tmp/dummynet
    sudo pfctl -e
    sudo dnctl show
}

stop()
{
    rm -rf /tmp/dummynet
    sudo pfctl -f /etc/pf.conf 
    sudo pfctl -d
    sudo dnctl -q flush
    sudo dnctl show
}

case "$1" in

prepare)
        prepare
        ;;

start)
        start
        ;;

stop)
        stop
        ;;
esac