source: hybrid/trunk/nanobsd/files/usr/local/bin/pen_wrapper@ 10136

#!/bin/sh
# Pen proxy wrapper, periodic check for best connections 
# Stichting Wireless Leiden
# Rick van der Zwet <rick@wirelessleiden.nl>

BIND_ADDR=${1-172.31.255.1}
BIND_PORT=${2-3128}
DEBUG=0

#XXX: Really static list, some dynamic alternative prefered
PROXY_LIST="${3-172.17.8.68:3128 172.17.143.4:3128 172.20.128.98:3128 172.16.2.254:3128 172.19.168.66:3128}"


TEST_URL="http://www.ams-ix.net/"
TEST_INTERVAL=`expr 30 \* 60` # Back-off period in seconds, re-testing period


# Don't touch, unless you know what you are doing
PIDFILE='/var/run/pen.pid'
PEN='/usr/local/bin/pen'
PEN_FLAGS="-b 30 -r -p ${PIDFILE} -o prio ${BIND_ADDR}:${BIND_PORT}"

LOGFILE='/var/log/pen_wrapper.log'

log()
{
        _datestamp=`date "+%Y-%m-%d %H:%M:%S"`
        _msg="[${_datestamp}] $*"
        if [ ${DEBUG} -eq 0 ]; then
                echo "${_msg}" >> ${LOGFILE}
        else
                echo "${_msg}"
        fi
}

d_log() {
        if [ ${DEBUG} -ne 0 ]; then
                log $*
        fi
}

test_proxy()
{
        # Set proxy
        PROXY=$1
        PORT=$2
        URL=$3
        export HTTP_PROXY="${PROXY}:${PORT}"

        # Attempted fetch
        retstr=`fetch -T 3 -o /dev/null ${URL} 2>&1`
        retval=$?

        # Store to list if successfull
        if [ "${retval}" -eq  0 ]; then
                BPS=`echo "${retstr}" | awk '/Bps/ {printf $4}'`
                echo "${BPS} ${PROXY}" >> ${TMPFILE}
        fi
        return $retval
}

sort_proxies()
{
        # Result holder
        TMPFILE=`mktemp -t pen_wrapper`

        for _host in ${PROXY_LIST}; do
                PROXY=`echo $_host | cut -d ":" -f1`
                PORT=`echo $_host | cut -d ":" -f2`
                _msg="Fetching '${TEST_URL}' via '${PROXY}:${PORT}' ..."
                test_proxy ${PROXY} ${PORT} ${TEST_URL} && d_log ${_msg} "OK" || d_log ${_msg} "FAILED"
        done

        _proxylist=`sort -nr ${TMPFILE} | awk '{print $2}' | tr '\n' ' '`
        _cfg="0:0:1:1"
        if [ -n "${_proxylist}" ]; then
                _prio="0"
                _proxy_arg=""
                for _proxy in ${_proxylist}; do
                        _prio=`expr ${_prio} + 1`
                        _proxy_arg="${_proxy_arg} ${_proxy}:${PORT}:${_cfg}:${_prio}"
                done
        fi
        # Clear out junk
        rm -f ${TMPFILE}
        NEW_PROXY_LIST="${_proxy_arg}"
}


##
# Main loop
LIVE_PROXY_LIST=''
while true; do
        sort_proxies
        if [ "${LIVE_PROXY_LIST}" != "${NEW_PROXY_LIST}" ]; then
                log "INFO: New listing to be configured '${NEW_PROXY_LIST}'"
                d_log "Live: ${LIVE_PROXY_LIST}"
                d_log "New : ${NEW_PROXY_LIST}"
                # Pen should only be started if alias exists
                ifconfig | grep -q ${BIND_ADDR}
                if [ $? -eq 0 ]; then
                        if [ -r ${PIDFILE} ]; then
                                kill `cat ${PIDFILE}`
                        fi
                        ${PEN} ${PEN_FLAGS} ${NEW_PROXY_LIST}
                        LIVE_PROXY_LIST="${NEW_PROXY_LIST}"
                fi
        fi
        sleep ${TEST_INTERVAL}
done