#!/bin/sh

# Copyright (C) 2008, 2009 Nicira Networks, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

OPENFLOWD_PID=/var/run/ovs-openflowd.pid
OPENFLOWD_SOCK=/var/run/ovs-openflowd.mgmt
LOG_FILE=/var/log/openflow/monitor
INTERVAL=1
FAIL_THRESH=3

usage() {
    echo usage: $0 options
    echo
    echo "OPTIONS:"
    echo "  -h   Show this message"
    echo "  -p   PID file for ovs-openflowd (default: $OPENFLOWD_PID)"
    echo "  -s   Unix socket for ovs-openflowd (default: $OPENFLOWD_SOCK)"
    echo "  -l   File to log messages (default: $LOG_FILE)"
    echo "  -i   Interval to send probes in seconds (default: $INTERVAL)"
    echo "  -c   Number of failed probes before reboot (default: $FAIL_THRESH)"
}

log() {
    echo `date +"%b %d %X"`:$1 
    echo `date +"%b %d %X"`:$1 >> $LOG_FILE
}


while getopts "hp:s:l:i:c:" OPTION; do
    case $OPTION in
        h)
            usage
            exit 1
            ;;

        p) 
            OPENFLOWD_PID=$OPTARG
            ;;

        s) 
            OPENFLOWD_SOCK=$OPTARG
            ;;

        l) 
            LOG_FILE=$OPTARG
            ;;

        i) 
            INTERVAL=$OPTARG
            ;;

        c) 
            FAIL_THRESH=$OPTARG
            ;;

        *)
            echo "Unknown option: ${OPTION}"
    esac
done


if [ ! -f $OPENFLOWD_PID ]; then
    log "No ovs-openflowd pid file: ${OPENFLOWD_PID}"
    echo "No ovs-openflowd pid file: ${OPENFLOWD_PID}"
fi

if [ ! -S $OPENFLOWD_SOCK ]; then
    log "No ovs-openflowd sock file: ${OPENFLOWD_SOCK}"
    echo "No ovs-openflowd sock file: ${OPENFLOWD_SOCK}"
fi

if [ ! -d `dirname $LOG_FILE` ]; then
    mkdir -p `dirname $LOG_FILE`
fi

let DP_DOWN=0
let OPENFLOWD_DOWN=0
log "===== Starting Monitor ===="
while `/bin/true`; do
    # Only check for liveness if ovs-openflowd's PID file exists.  The PID
    # file is removed when ovs-openflowd is brought down gracefully.
    if [ -f $OPENFLOWD_PID ]; then
        pid=`cat $OPENFLOWD_PID`
        if [ -d /proc/$pid ]; then
            # Check if the ovs-openflowd and datapath still can communicate
            if [ -S $OPENFLOWD_SOCK ]; then
                ovs-ofctl probe -t 2 unix:$OPENFLOWD_SOCK
                if [ $? -ne 0 ]; then
                    log "datapath probe failed"
                    let DP_DOWN++
                else 
                    let DP_DOWN=0
                fi
            fi
            let OPENFLOWD_DOWN=0
        else
            log "ovs-openflowd probe failed"
            let OPENFLOWD_DOWN++
        fi
    fi

    if [ $OPENFLOWD_DOWN -ge $FAIL_THRESH ]; then
        log "Failed to probe ovs-openflowd after ${OPENFLOWD_DOWN} tries...rebooting!"
        reboot
    fi

    if [ $DP_DOWN -ge $FAIL_THRESH ]; then
        log "Failed to probe datapath after ${DP_DOWN} tries...rebooting!"
        reboot
    fi

    sleep $INTERVAL 
done