#!/bin/bash
# -*-shell-mode-*-

### expected to be run as root

COMMAND=$0

#################### global vars
RUN_DIR=@RUNDIR@
DB_CONF_FILE=@DBDIR@/conf.db
DB_SCHEMA=@pkgdatadir@/vswitch.ovsschema
DB_LOG=@LOGDIR@/ovs-db.log
##
DB_SOCKET=$RUN_DIR/db.sock
##
SWITCH_LOG=@LOGDIR@/ovs-switch.log

#################### helper functions

function kill_pltap_ovs () {
    killall pltap-ovs 2>/dev/null || :
}

function error {
    echo "$@" >&2
    exit 1
}

function get_params {
    params=$1; shift
    err_msg="$COMMAND $SUBCOMMAND $(echo $params | perl -pe 's/\S+/<$&>/g')"
    for p in $params; do
        [[ -z "$@" ]] && error "$err_msg"
        pname=$(echo -n $p|perl -pe 's/\W/_/g')
        eval $pname="$1"; shift
    done
    [[ -n "$@" ]] && error "$err_msg"
}

function is_switch_running {
    ovs-appctl --target=ovs-vswitchd version >& /dev/null
}

function is_db_running {
    ovs-appctl --target=ovsdb-server version >& /dev/null
}

function tapname () {
    IP=$1; shift
    echo $(ip addr show to "$IP/32" | perl -ne '/^\s*\d+:\s*([\w-]+):/ && print $1')
}
    
function wait_server () {
    pid_file=$1; shift
    server_name=$1; shift
    timeout=$1; shift

    expire=$(($(date +%s) + $timeout))

    ## wait for it to be up - xxx todo - could use a timeout of some kind
    while [ ! -f "$pid_file" ]; do
	echo "Waiting for $server_name to start... $(($expire - $(date +%s)))s left" >&2
	sleep 1;
	[ $(date +%s) -ge $expire ] && return 1
    done
    cat "$pid_file"
}

function wait_device () {
    local tapname=$1; shift
    local timeout=$1; shift

    local expire=$(($(date +%s) + $timeout))

    while ! ip link show up | egrep -q "^[0-9]+: +$tapname:"; do
	echo "Waiting for $tapname to come UP...$(($expire - $(date +%s)))s left" >&2
	sleep 1
	[ $(date +%s) -ge $expire ] && return 1
    done
    return 0
}

######################################## startup
function start_db () {
    get_params "" "$@"

    ## init conf
    conf_dir=$(dirname $DB_CONF_FILE)
    [ -d $conf_dir ] || mkdir -p $conf_dir
    [ -f $DB_CONF_FILE ] || ovsdb-tool create $DB_CONF_FILE $DB_SCHEMA

    ## init run
    [ -d $RUN_DIR ] || mkdir -p $RUN_DIR

    ## check 
    [ -f $DB_CONF_FILE ] || { echo "Could not initialize $DB_CONF_FILE - exiting" ; exit 1 ; }
    [ -d $RUN_DIR ] || { echo "Could not initialize $RUN_DIR - exiting" ; exit 1 ; }

    ## run the stuff
	ovsdb-server $DB_CONF_FILE \
	    --remote=punix:$DB_SOCKET \
	    --remote=db:Open_vSwitch,Open_vSwitch,manager_options \
	    --private-key=db:Open_vSwitch,SSL,private_key \
	    --certificate=db:Open_vSwitch,SSL,certificate \
	    --bootstrap-ca-cert=db:Open_vSwitch,SSL,ca_cert \
	    --pidfile \
	    --log-file=$DB_LOG \
	    --detach >& /dev/null
    wait_server $RUN_DIR/ovsdb-server.pid ovsdb-server 30
}

function start_switch () {
    get_params "" "$@"

    # ensure ovsdb-server is running
    is_db_running || { echo "ovsdb-server not running" >&2 ; exit 1 ; }

	ovs-vswitchd \
	    --pidfile \
	    --log-file=$SWITCH_LOG \
	    --detach \
	    unix:$DB_SOCKET >& /dev/null
    wait_server $RUN_DIR/ovs-vswitchd.pid ovs-vswitchd 30
}

function stop_db () { 
    ovs-appctl --target=ovsdb-server exit || :
}

function stop_switch () { 
    ovs-appctl --target=ovs-vswitchd exit || :
}

function status () {
    pids=$(pgrep '^ovs')
    [ -n "$pids" ] && ps $pids
}

function start () {
    start_db
    start_switch
}

function stop () {
    stop_switch
    stop_db
}

#################### create functions
function create_bridge () {
    
    get_params "bridge IP/PREFIX" "$1" "$2"
    shift; shift;

    IP=${IP_PREFIX%/*}
    PREFIX=${IP_PREFIX#*/}

    W=
    if ! is_switch_running; then
    	# we can create the bridge even if ovs-vswitchd is not running,
	# but we need a running ovsdb-server
    	is_db_running || { echo "ovsdb-server not running" >&2; exit 1; }
    	W="--no-wait"
    fi


    set -e
    ovs-vsctl --db=unix:$DB_SOCKET $W -- --may-exist add-br "$bridge" \
    	-- set bridge "$bridge" datapath_type=planetlab \
	-- set interface "$bridge" options:local_ip="$IP" option:local_netmask="$PREFIX" \
	-- "$@"

    # check that the bridge has actually been created
    if [ -z "$W" ]; then
	    local tap=$(ovs-appctl netdev-pltap/get-tapname "$bridge")
	    wait_device $tap 10
    fi
}

function create_port () {

    get_params "bridge port" "$@"
   
    W=
    if ! is_switch_running; then
    	# we can create the port even if ovs-vswitchd is not running,
	# but we need a running ovsdb-server
    	is_db_running || { echo "ovsdb-server not running" >&2; exit 1; }
    	W="--no-wait"
    fi

    set -e
    ovs-vsctl --db=unix:$DB_SOCKET $W -- --may-exist add-port "$bridge" "$port" \
        -- set interface "$port" type=tunnel
}

function get_local_endpoint () {

    get_params "local_port" "$@"

    is_switch_running || { echo "ovs-vswitchd not running" >&2; exit 1; }

    set -e
    ovs-appctl --target=ovs-vswitchd netdev-tunnel/get-port "$local_port"
}

function set_remote_endpoint () {

    get_params "local_port remote_ip remote_UDP_port" "$@"

    W=
    if ! is_switch_running; then
    	# we can store the info even if ovs-vswitchd is not running,
	# but we need a running ovsdb-server
    	is_db_running || { echo "ovsdb-server not running" >&2; exit 1; }
    	W="--no-wait"
    fi

    set -e
    ovs-vsctl --db=unix:$DB_SOCKET $W set interface $local_port \
        options:remote_ip=$remote_ip \
	options:remote_port=$remote_UDP_port
}

function set_controller () {

    get_params "bridge_name controller" "$@"

    # ensure ovs-vswitchd is running
    is_switch_running || { echo "ovs-vswitchd not running" >&2 ; exit 1 ; }

    set -e
    ovs-vsctl --db=unix:$DB_SOCKET set-controller "$bridge_name" "$controller"
}

function del_controller () {

    get_params "bridge_name" "$@"

    # ensure ovs-vswitchd is running
    is_switch_running || { echo "ovs-vswitchd not running" >&2 ; exit 1 ; }

    set -e
    ovs-vsctl --db=unix:$DB_SOCKET del-controller "$bridge_name"
}

#################### del functions
function del_bridge () {
    
    get_params "bridge_name" "$@"

    W=
    if ! is_switch_running; then
    	# we can delete the bridge even if ovs-vswitchd is not running,
	# but we need a running ovsdb-server
    	is_db_running || { echo "ovsdb-server not running" >&2; exit 1; }
    	W="--no-wait"
    fi

    ovs-vsctl --db=unix:$DB_SOCKET $W -- --if-exists del-br $bridge_name
}

function del_port () {
    
    get_params "port" "$@"

    W=
    if ! is_switch_running; then
    	# we can delete the port even if ovs-vswitchd is not running,
	# but we need a running ovsdb-server
    	is_db_running || { echo "ovsdb-server not running" >&2; exit 1; }
    	W="--no-wait"
    fi

    ovs-vsctl --db=unix:$DB_SOCKET $W -- --if-exists del-port "$port"
}

function show () {

    get_params "" "$@"

    is_db_running || { echo "ovsdb-server not running" >&2; exit 1; }

    ovs-vsctl --db=unix:$DB_SOCKET show
}

function get_local_ip () {

    get_params "bridge" "$@"

    set -e
    ovs-vsctl --db=unix:$DB_SOCKET br-exists "$bridge" || return
    local ip=$(ovs-vsctl get interface "$bridge" options:local_ip)
    local netmask=$(ovs-vsctl get interface "$bridge" options:local_netmask)
    eval echo $ip/$netmask
}

function get_local_links () {

    get_params "bridge" "$@"

    set -e
    ovs-vsctl --db=unix:$DB_SOCKET br-exists "$bridge" || return
    ovs-vsctl --db=unix:$DB_SOCKET list-ifaces "$bridge"
}

function get_mac () {

    get_params "bridge" "$@"

    set -e
    local tap=$(ovs-appctl netdev-pltap/get-tapname "$bridge")
    ifconfig "$tap" | awk '/HWaddr/ { print $5 }'
}

### for demos - connect to an ndnmap deployment to visualize links bandwidth
# this expects 3 arguments
# an interface name, L<id1>-<id2> based on your ids in conf.mk
# the hostname for a ndnmap deployment
# a linkid, this is the id that this link has in your ndnmap scenario (hard-coded in some json file)
# this one-shot function writes the current statistics onto the ndnmap site
# it needs to be called regularly so that ndnmap can do the bw computations
# would make sense for the caller to redirect stderr onto some relevant location
function gmap_probe_once () {
    iface=$1; shift
    hostname=$1; shift
    linkid=$1; shift
    rx_bytes=$(ovs-appctl netdev-tunnel/get-rx-bytes $iface)
    tx_bytes=$(ovs-appctl netdev-tunnel/get-tx-bytes $iface)
    rx_bits=$(($rx_bytes*8))
    tx_bits=$(($tx_bytes*8))
    now=$(date +%s).$(date +%N)
    trigger=http://${hostname}/bw/${linkid}/${now}/${rx_bits}/${tx_bits}
#    curl -s -L $trigger | grep -q "Got it" || echo Missed event with $trigger
#    echo $trigger
    curl -s -L $trigger >& /dev/null
}

### the front end, manages pid and so on
function gmap_probe () {
    iface=$1; shift
    hostname=$1; shift
    linkid=$1; shift
    looptime=$1; shift
    [ -z "$looptime" ] && looptime=1
    pid_file=/var/run/openvswitch/gmap-$iface.pid
    if [ -f $pid_file ] ; then
	pid=$(cat $pid_file)
	[ -n "$pid" ] && kill $pid >& /dev/null
	rm $pid_file
    fi
    # close std fds so that ssh invokations can return
    exec <&-
    exec >&-
    while true; do
	gmap_probe_once $iface $hostname $linkid
	sleep $looptime
    done &
    # this is the pid for the background process
    echo $! > $pid_file
}

####################
SUPPORTED_SUBCOMMANDS="start stop status 
start_db stop_db start_switch stop_switch
create_bridge create_port del_bridge del_port
show get_local_endpoint set_remote_endpoint
set_controller del_controller gmap_probe
get_local_ip get_local_links get_mac"

function main () {
	message="Usage: $COMMAND <subcommand> ...
Supported subcommands are (dash or underscore is the same):
$SUPPORTED_SUBCOMMANDS"
	[[ -z "$@" ]] && error "$message"

	SUBCOMMAND=$1; shift
	# support dashes instead of underscores
	SUBCOMMAND=$(echo $SUBCOMMAND | sed -e s,-,_,g)
        found=""
        for supported in $SUPPORTED_SUBCOMMANDS; do [ "$SUBCOMMAND" = "$supported" ] && found=yes; done

	[ -z "$found" ] && error $message

	$SUBCOMMAND "$@"
}

main "$@"