Linksys guest network login script

#! /bin/sh

# +---------------------------------
# Enter madtown pw: dd
# Sanity check:
# 	default iface en0
# 	mac_addr 0c:e4:41:d9:63:89
# 	ip_addr 192.168.1.202
# 
# Type Y to proceed.
# y
# curl -H X-JNAP-Action: http://cisco.com/jnap/guestnetwork/Authenticate --data {"macAddress":"","ipAddress":"","password":"dd"} -X POST http://192.168.3.1:10080/JNAP/
# + --------------------------------

DEF_IFACE="$(route -n get default | awk '/interface/{print $2}')"
MAC_ADDR="$(ifconfig $DEF_IFACE | awk '/ether/{print $2}')"
IP_ADDR="$(ifconfig $DEF_IFACE | awk '/inet / {print $2}')"

if [ -z "${MADTOWN_PASS}" ]
then
	echo -n "Enter madtown pw: "
	read MADTOWN_PASS
fi

echo -e  "Sanity check:\n\tdefault iface $DEF_IFACE\n\tmac_addr $MAC_ADDR\n\tip_addr $IP_ADDR\n"
echo "Type Y to proceed."
read PROCEED
# https://stackoverflow.com/questions/226703/how-do-i-prompt-for-yes-no-cancel-input-in-a-linux-shell-script/27875395#27875395
if [ "$PROCEED" != "${PROCEED#[yY]}" ]
then
	curl -H "X-JNAP-Action: http://cisco.com/jnap/guestnetwork/Authenticate" --data "{\"macAddress\":\"$MAC_ADDR\",\"ipAddress\":\"$IP_ADDR\",\"password\":\"${MADTOWN_PASS}\"}" -X POST http://192.168.3.1:10080/JNAP/
else
	echo "aborted"
fi