DD-WRT Unknown client notification

dhcp-lease-notifier.sh

#!/bin/sh
#
# Details:
#   Author: Lars Erik Storbukås <[email protected]>
#           http://larserik.storbukas.no
#   System: DD-WRT v3.0-r28628 std (12/29/15)
#   File location: /jffs/ets/scripts/dhcp-lease-notifier.sh
#
# DHCP Lease Notifier
# ------------------------
# This script notifies about unknown clients upon DHCP lease. Any hosts
# connecting to the router is appended to a list of known clients. This
# means that you will only receive one notification per device (NIC).
#
# This will be called by DNSMasq every time a new device is connected
# (when configured) with the following arguments:
#   $1 = add | old
#   $2 = mac address
#   $3 = ip address
#   $4 = device name
#
# The following DNSMasq option must be added through the DD-WRT web interface,
# at Services > Services > DNSMasq > Additional DNSMasq Options:
#    dhcp-script=/jffs/etc/scripts/dhcp-lease-notifier.sh
#
# Remember to make this script executable by issuing the following command:
#    chmod +x /jffs/etc/scripts/dhcp-lease-notifier.sh
#
# The notification command uses a SMS Gateway to notify the network
# administrator about the unknown client.
#
# In order for this script to work properly, you must either replace the
# notification command, or provide an API key for https://gatewayapi.com.

# DNSMasq arguments
action="${1:-op}"
mac="${2:-mac}"
ip="${3:-ip}"
hostname="${4}"

# Details
known_mac_addr="/jffs/etc/scripts/known_mac_addr"
timestamp="`date '+%d-%m-%Y %H:%M:%S'`"

# SMS API Configuration
sms_api_key="<INSERT API KEY>" # API Key
sms_api_key_passwd="" # Normally empty
sms_sender="<INSERT SMS SENDER ID>" # Max 11 characters
sms_area_code="47" # Norway area code
sms_recipient="<INSERT SMS RECEIVER ID>" # Phone number of recipient

# Notification message
payload="A new device has connected to the network.

Mac: ${mac}
IP: ${ip}
Time: ${timestamp}
Hostname: ${hostname}"

# Search for the MAC-address in known_mac_addr-file
grep -q "$2" "$known_mac_addr"
unknown_mac_addr=$?

# Check if search found a match - if not, then notify
if [ "$unknown_mac_addr" -ne 0 ]; then
    # Add MAC to known_mac_addr-file
    echo $mac >> $known_mac_addr

    # Notification command
    curl -k -v https://gatewayapi.com/rest/mtsms \
      -u ${sms_api_key}:${sms_api_key_passwd} \
      -d sender="${sms_sender}" \
      -d message="${payload}" \
      -d recipients.0.msisdn=${sms_area_code}${sms_recipient}
fi