#! /bin/bash
#include INTEL_LICENSE.txt
#
########################################################################
#
# PlanetLab Ping Of Death
#
########################################################################
#
# DESCRIPTION
#
# This shell script takes care of starting and stopping Planetlab
# Ping-Of-Death.
#
# The Planetlab POD is a Linux kernel patch that creates the feature
# of resetting and rebooting a computer when a particularily
# formatted ICMP "ping" commmand is received.
#
# A PlanetLab node's kernel gets a host, mask and hash value through
# sysctl's that are performed on the node.  The node then looks
# for an ICMP packet from a host matching the host/mask and, if the
# packet payload is the hash value, the node forces an immediate
# reboot.
#
# HISTORY
#
# May 17, 2003    -   Paul Brett <paul.brett@intel.com>
#                     Initial version based on the work of 
#                     Robert Adams <robert.adams@intel.com> and EMULAB
#
# chkconfig: - 11 99
# description: enable Ping of Death

# Source function library.
. /etc/init.d/functions

# Source networking configuration.
. /etc/sysconfig/network

function enable_pod()
{
    local SYSCTL=/sbin/sysctl

    local IP_SUBNET=$1
    local IP_MASK=$2
    local HASH=$3

    # Grotesque sed/awk converts IP addrs into an integer for sysctl
    local IPODHOST=`echo $IP_SUBNET | \
              sed -e 's/\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\).*/\1 \2 \3 \4/' | \
              awk '{ printf "%d\n", $1*16777216+$2*65536+$3*256+$4 }'`
    local IPODMASK=`echo $IP_MASK | \
              sed -e 's/\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\).*/\1 \2 \3 \4/' | \
              awk '{ printf "%d\n", $1*16777216+$2*65536+$3*256+$4 }'`

    # figure out the version
    local version=`$SYSCTL net.ipv4.icmp_ipod_version 2>/dev/null`
    if [[ "$version" == "" ]]
    then
        $SYSCTL net.ipv4.icmp_ipod_enabled >/dev/null 2>&1
        case $? in
            0)
                version=1
                ;;
            *)
                version=0
                ;;
        esac
    fi

    # enable if possible
    case $version in
        0)
            return 1
            ;;
        1)
            $SYSCTL -w net.ipv4.icmp_ipod_host=$IPODHOST >/dev/null
            $SYSCTL -w net.ipv4.icmp_ipod_enabled=1 >/dev/null
            Success=0
            ;;
        *)
            $SYSCTL -w net.ipv4.icmp_ipod_host=$IPODHOST >/dev/null
            Success=$?
            $SYSCTL -w net.ipv4.icmp_ipod_mask=$IPODMASK >/dev/null
            $SYSCTL -w net.ipv4.icmp_ipod_key=$HASH >/dev/null
            $SYSCTL -w net.ipv4.icmp_ipod_enabled=1 >/dev/null
        ;;
    esac
    return $Success
}

function disable_pod()
{
    local SYSCTL=/sbin/sysctl
    $SYSCTL -w net.ipv4.icmp_ipod_enabled=0 >/dev/null
    return 0
}

function status_pod()
{

    local SYSCTL="/sbin/sysctl"

    # Check that IPOD is built into this kernel
    local version
    version=`$SYSCTL -n net.ipv4.icmp_ipod_version 2> /dev/null`
    if [[ $? -ne 0 ]]
    then
        echo "Not installed"
        return 255
    fi

    # Check if it has been enabled
    local enabled=`$SYSCTL -n net.ipv4.icmp_ipod_enabled`
    echo -n "version $version "
    if [[ $enabled -eq 1 ]]
    then 
        echo "Enabled"
    else 
        echo "Disabled"
    fi
    return $enabled
}

echo -n "PlanetLab Ping Of Death "

CONF=/etc/ipod.conf

if [[ -r $CONF ]]
then
    # load the POD configuration file
    . $CONF
else
    # no POD configuration file - failed
    echo
    action $"Missing configuration file $CONF" /bin/false
    exit 1
fi

SESSION=/etc/planetlab/session

if [[ -r $SESSION ]]
then
    # load the session value file
    HASH=`cat $SESSION`
else
    # no session value (ie, no hash)
    echo
    action $"Missing node session file $SESSION" /bin/false
    exit 1
fi

# Check that networking is up.
if [[ ${NETWORKING} = "no" ]]
then
    action $"" /bin/false
    exit 1
fi

# Check the POD parameters
if [[ "$HASH" == "" ]]
then
    echo 
    action $"Missing HASH (from $SESSION)" /bin/false
    exit 1
fi

if [[ "$IP_SUBNET" == "" ]]
then
    echo
    action $"Missing IP_SUBNET in $CONF" /bin/false
    exit 1
fi

if [[ "$IP_MASK" == "" ]]
then
    echo
    action $"Missing IP_MASK in $CONF" /bin/false
    exit 1
fi

# See how we were called.
case "$1" in
  start)
        enable_pod $IP_SUBNET $IP_MASK $HASH
        RETVAL=$?
        if [[ $RETVAL -eq 0 ]]
        then
            action $"" /bin/true
        else
            action $"" /bin/false
        fi
        ;;
  stop)
        disable_pod
        RETVAL=$?
        if [[ $RETVAL -eq 0 ]]
        then
            action $"" /bin/true
        else
            action $"" /bin/false
        fi
        ;;
  status)
        status_pod
        RETVAL=$?
        ;;
  restart|reload)
        disable_pod
        enable_pod
        RETVAL=$?
        ;;
  *)
        echo $"Usage: $0 {start|stop|restart|status}"
        exit 1
esac