#!/bin/sh
#
# fanctl - control fan bridge devices
#   fanctl up 15 10.1.0.1
#   fanctl down 15 10.1.0.1
#

usage()
{
	echo "Usage: $0 <cmd> [<options>...]" 1>&2
	echo "Available commands:" 1>&2
	echo "	up       - bring up Fans" 1>&2
	echo "	down     - bring down configured Fans" 1>&2
	echo "	show     - show configured Fans" 1>&2
	echo "	config   - manage local persistent configuration for Fans" 1>&2
	echo "Use $0 help [<cmd>] for more details" 1>&2
}

run()
{
	last_cmd="$@"
	[ "$opt_v" ] && echo "$@"
	"$@"
}

state_dir="/run/ubuntu-fan"
lconfig_dir="/var/lib/ubuntu-fan/config"

__ip_split()
{
	eval `echo "$1" | {
		IFS=./ read a b c d e f
		echo ip_a="$a" ip_b="$b" ip_c="$c" ip_d="$d" ip_e="$e"
	}`
}

width_to_mask()
{
	local width="$1"
	local mask=""
	local zeros="$(( (32-$width)/4 ))"

	while [ "$width" -ge 4 ]; do
		mask="${mask}F"
		width="$(($width - 4))"
	done
	case "$width" in
	3)	mask="${mask}E" ;;
	2)	mask="${mask}C" ;;
	1)	mask="${mask}8" ;;
	esac

	while [ "$zeros" -gt 0 ]; do
		mask="${mask}0"
		zeros="$(($zeros - 1))"
	done

	#printf "%x %x\n" "$((0x$mask))" "$(( (~0x$mask) & 0xffffffff ))"

	RET="$(( 0x$mask ))"
}

ip_to_num_width()
{
	local ip_a
	local ip_b
	local ip_c
	local ip_d
	local ip_e
	local ip_f

	__ip_split "$1"

	RET="$(( ($ip_a << 24) | ($ip_b << 16) | ($ip_c << 8) | $ip_d ))"
	RET2="$ip_e"
}

num_to_ip()
{
	local ip_num="$1"
	local ip_sep="$2"

	[ "$ip_sep" = '' ] && ip_sep='.'

	RET="$(( (($ip_num >> 24) & 0xff) ))$ip_sep$(( (($ip_num >> 16) & 0xff) ))$ip_sep$(( (($ip_num >> 8) & 0xff) ))$ip_sep$(( $ip_num & 0xff ))"
}

overlay_device()
{
	local format="$1"
	local a1="$2"

	case "$format" in
	A)		overlay="$a1" ;;
	*)		fail "$overlay: unknown overlay network format" ;;
	esac
}

underlay_device()
{
	local format="$1"
	local a1="$2"
	local a2="$3"

	case "$format" in
	A)		underlay="$a1" ;;
	B)		[ "$a1" = "default" ] && a1=`ip route show 0.0.0.0/0 | awk '{print $5; exit}'`
			a1="`ip -4 addr show dev "$a1" | grep inet | awk -F '[/ ]*' '{print $3; exit}'`"
			[ "$a1" = "" ] && fail "$a1: device address not found"
			underlay="$a1/$a2" 
			;;
	*)		fail "$underlay: unknown underlay network format" ;;
	esac
}

__underlay_lookup_address()
{
	local ipnum="$1"
	local width="$2"

	width_to_mask "$width"
	local tmp
	local interface
	local what
	local address
	local address_mask="$RET"
	local address_ipnum
	local address_ipnum_prefix
	local address_prefix

	address_prefix="$(( $ipnum & $address_mask ))"
	# If an address on the network was specified find exactly that.
	if [ "$ipnum" -ne "$address_prefix" ]; then
		address_prefix="$ipnum"
		address_mask="$(( ~0 ))"
	fi

	ip -o addr show | \
	while read tmp interface what address tmp
	do
		case "$what" in
		inet)
			ip_to_num_width "$address"
			address_ipnum="$RET"
			address_ipnum_prefix="$(( $RET & $address_mask ))"
			if [ "$address_ipnum_prefix" -eq "$address_prefix" ]; then
				num_to_ip "$address_ipnum"
				echo "$RET/$width"
			fi
			;;
		esac
	done
}

underlay_lookup_address()
{
	local underlay="$1"

	# Find matching address(es) ...
	ip_to_num_width "$underlay"
	local underlay_raw_ipnum="$RET"
	local underlay_width="$RET2"

	eval RET=\'$(__underlay_lookup_address "$underlay_raw_ipnum" "$underlay_width")\'
}

networks_decode_overlay()
{
	local overlay="$1"

	#echo "APW: networks_decode_overlay <$overlay>"
	local format="`echo "$overlay" | sed -n \
		-e 's@^\([0-9][0-9]*\)$@A \1.0.0.0/8@p' \
		-e 's@^\([0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\/[0-9][0-9]*\)$@A \1@p'
	`"
	overlay_device $format
	RET="$overlay"
}
networks_decode_underlay()
{
	local underlay="$1"

	#echo "APW: networks_decode_underlay <$underlay>"
	local format="`echo "$underlay" | sed -n \
		-e 's@^\([0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\)$@A \1/16@p' \
		-e 's@^\([0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\/[0-9][0-9]*\)$@A \1@p' \
		-e 's@^\([a-z][a-z]*[0-9][0-9]*\|default\)$@B \1 16@p' \
		-e 's@^\([a-z][a-z]*[0-9][0-9]*\|default\)/\([0-9][0-9]*\)$@B \1 \2@p' \
	`"
	underlay_device $format
	RET="$underlay"
}

validate_flags()
{
	local flag

	for flag in "$@"
	do
		case "$flag" in
		_*)	fail "$flag: invalid flag specified" ;;
		esac
	done
}

cmd_decode_init()
{
	C_flag_dhcp=''
	C_flag_debug=''
	C_flag_enable=''
	C_flag_auto=''
	C_flag_host_reserve=1
	C_flag_bridge=''
	C_flag_type='vxlan'
	C_flag_mode='compact'
	C_flag_i_device=''
}

cmd_decode_legacy()
{
	local name="$1"
	shift

	#echo "$0: $name: WARNING using legacy fan format, see fanctl(8) for details ($@)" 1>&2

	local addresses=y
	local args

	[ "$1" = '--' ] && shift

	# XXX: we should be using the sed from network_decode_addresses()
	case "$1" in
	*.*.*.*/*)	;;
	*)		addresses=n ;;
	esac
	case "$2" in
	*.*.*.*/*)	;;
	*)		addresses=n ;;
	esac

	if [ "$addresses" = 'n' ]; then
		fail "$name: invalid specifier ($1)"
	fi

	args="-o '$1' -u '$2'"
	shift 2

	while [ "$#" -gt 0 ]
	do
		case "$1" in
		type|mode|host-reserve|bridge)
			args="$args --$1='$2'"
			shift
			;;
		dhcp|off)
			args="$args --$1"
			;;
		*)
			fail "$name: invalid specifier ($1)"
			;;
		esac
		shift
	done

	echo "$args"
}

cmd_decode_payload()
{
	##echo "cmd_decode_payload($@)"

	while [ "$#" -gt 0 ]
	do
		flag="$1"
		flagv=`echo "$flag" | sed -e s/^--// -e s/-/_/g`
		shift

		#echo "<$flag>"
		case "$flag" in
		--)
			break
			;;
		-u|--underlay)
			C_underlay="$1"
			shift
			;;
		-o|--overlay)
			C_overlay="$1"
			shift
			;;
		--enable|--on)
			C_flag_enable=y
			;;
		--disable|--off)
			C_flag_enable=
			;;
		--dhcp|--auto)
			eval C_flag_${flagv}=y
			;;
		--host-reserve)
			arg=`echo "I:$1" | sed -n \
				-e 's/^I:\([0-9][0-9]*\)$/\1/p' \
				-e 's/^I:.*$/E/p'`
			[ "$arg" = 'E' ] && fail "$1: malformed $flag flag argument -- integer expected"
			shift

			eval C_flag_$flagv=$arg
			;;
		--bridge)
			C_flag_bridge="$1"
			shift
			;;
		--type)
			C_flag_type="$1"
			shift

			case "$C_flag_type" in
			ipip)		version='0'
					[ ! -f /proc/sys/net/fan/version ] && modprobe ipip
					[ -f /proc/sys/net/fan/version ] && version=`cat /proc/sys/net/fan/version`
					[ "$version" -eq 0 ] && fail "no ipip fan support availabe in the kernel"
					[ "$version" -lt 3 ] && C_flag_type="ipip1"
					;;
			vxlan)		version='0'
					[ ! -f /proc/sys/net/fan/vxlan ] && modprobe vxlan
					[ -f /proc/sys/net/fan/vxlan ] && version=`cat /proc/sys/net/fan/vxlan`
					[ "$version" -eq 0 ] && fail "no vxlan fan support availabe in the kernel"
					;;
			*)		fail "$C_flag_type: unknown tunnel protocol type (ipip or vxlan expected)" ;;
			esac

			;;
		--mode)
			C_flag_mode="$1"
			shift
			case "$C_flag_mode" in
			sliced|compact)	;;
			*)		fail "$C_flag_mode: unknown bridge mode" ;;
			esac
			;;
		--comment)
			shift
			;;
		--i-device)
			C_flag_i_device="$1"
			shift
			;;
		*)
			fail "$flag: unknown flag"
			;;
		esac
	done

	if [ "$#" != 0 ]; then
		fail "invalid specifier ($@)"
	fi

	if [ "$C_overlay" != "" ]; then
		networks_decode_overlay "$C_overlay"
		C_overlay="$RET"
	fi
	if [ "$C_underlay" != "" ]; then
		networks_decode_underlay "$C_underlay"
		C_underlay="$RET"
	fi

	return 0
}

cmd_decode_short='u:o:'
cmd_decode_long_uo='underlay:,overlay:'
cmd_decode_long_all='enable,on,disable,off,dhcp,auto,host-reserve:,bridge:,type:,mode:'
cmd_decode_long_internal='i-device:'
cmd_decode_long_config='comment:'

cmd_decode_internal()
{
	TEMP=$(getopt \
		-n "$0" \
		-o "$cmd_decode_short" -l "$cmd_decode_long_uo" \
		-l "$cmd_decode_long_all" \
		-l "$cmd_decode_long_internal" \
		-- "$@"
	)
	if [ "$?" != 0 ]; then
		fail "invalid specifier -- parser failure"
	fi

	eval set -- "$TEMP"

	cmd_decode_payload "$@"
}
cmd_decode_all()
{
	local name="$1"
	shift 1

	#echo "<<$@>>"
	TEMP=$(getopt \
		-n "$0: $name" \
		-o "$cmd_decode_short" -l "$cmd_decode_long_uo" \
		-l "$cmd_decode_long_all" \
		-- "$@"
	)
	if [ "$?" != 0 ]; then
		fail "$name: invalid fan specifier option"
	fi
	#echo "<<<$TEMP>>>"
	eval set -- "$TEMP"

	if [ "$1" = '--' ]; then
		return 1
	fi

	cmd_decode_payload "$@"
}

cmd_decode_ou()
{
	local name="$1"
	shift

	TEMP=$(getopt \
		-n "$0: $name" \
		-o "$cmd_decode_short" -l "$cmd_decode_long_uo" \
		-- "$@"
	)
	if [ "$?" != 0 ]; then
		fail "$name: invalid fan specifier option"
	fi

	eval set -- "$TEMP"

	if [ "$1" = '--' ]; then
		return 1
	fi

	cmd_decode_payload "$@"
}

cmd_decode_config()
{
	local name="$1"
	shift 1

	#echo "<<$@>>"
	TEMP=$(getopt \
		-n "$0: $name" \
		-o "$cmd_decode_short" -l "$cmd_decode_long_uo" \
		-l "$cmd_decode_long_all" \
		-l "$cmd_decode_long_config" \
		-- "$@"
	)
	if [ "$?" != 0 ]; then
		fail "$name: invalid fan specifier option"
	fi
	#echo "<<<$TEMP>>>"
	eval set -- "$TEMP"

	cmd_decode_payload "$@"
}
cmd_decode_user()
{
	local name="$1"
	shift 1

	#echo "<<$@>>"
	TEMP=$(getopt \
		-n "$0: $name" \
		-o "$cmd_decode_short" -l "$cmd_decode_long_uo" \
		-l "$cmd_decode_long_all" \
		-l "$cmd_decode_long_config" \
		-- "$@"
	)
	if [ "$?" != 0 ]; then
		fail "$name: invalid fan specifier option"
	fi
	#echo "<<<$TEMP>>>"
	eval set -- "$TEMP"

	local flag
	local val
	RET=""
	RET2=""
	while [ "$#" -gt 0 ]
	do
		flag="$1"
		shift

		case "$flag" in
		--)
			break
			;;
		-u|--underlay|-o|--overlay)
			;;
		--enable|--on|--disable|--off|--dhcp|--auto)
			RET="$RET $flag"
			RET2="$RET2 $flag"
			;;
		--host-reserve|--bridge|--type|--mode)
			RET="$RET $flag=$1"
			RET2="$RET2 $flag=$1"
			shift
			;;
		--comment)
			val="$1"
			case "$val" in
			*\ *)	RET2="$RET2 $flag='$val'" ;;
			*)	RET2="$RET2 $flag=$1" ;;
			esac
			shift
			;;
		esac
	done

	RET="${RET## }"
	RET2="${RET2## }"
}

cmd_decode_show()
{
	RET=""
	[ "$C_flag_enable" ] && RET="${RET} enable"
	[ "$C_flag_dhcp" ] && RET="${RET} dhcp"
	[ "$C_flag_host_reserve" -a "$C_flag_host_reserve" != "1" ] && RET="${RET} host-reserve=${C_flag_host_reserve}"
	#[ "$C_flag_auto" ] && RET="${RET} auto"
	[ "$C_flag_bridge" ] && RET="${RET} bridge=${C_flag_bridge}"
	[ "$C_flag_type" -a "$C_flag_type" != "vxlan" ] && RET="${RET} type=${C_flag_type}"
	[ "$C_flag_mode" -a "$C_flag_mode" != "compact" ] && RET="${RET} mode=${C_flag_mode}"
}

networks_decode_one()
{
	C_user_flags="$@"

	cmd_decode_init
	cmd_decode_internal "$@"

	C_flags=''
	C_i_flags=''
	[ "$C_flag_enable" ] && C_flags="${C_flags} --enable"
	[ "$C_flag_dhcp" ] && C_flags="${C_flags} --dhcp"
	[ "$C_flag_host_reserve" ] && C_flags="${C_flags} --host-reserve=${C_flag_host_reserve}"
	[ "$C_flag_auto" ] && C_flags="${C_flags} --auto"
	[ "$C_flag_bridge" ] && C_flags="${C_flags} --bridge=${C_flag_bridge}"
	[ "$C_flag_type" ] && C_flags="${C_flags} --type=${C_flag_type}"
	[ "$C_flag_mode" ] && C_flags="${C_flags} --mode=${C_flag_mode}"

	# Decode and extract the base IP addresses and widths.
	overlay="$C_overlay"
	underlay="$C_underlay"
	##C_overlay="$overlay"
	##C_underlay="$underlay"

	C_slice_id=`echo "${overlay}-${underlay}" | sed -e 's@/@_@g'`
	C_slice_oid=`echo "${overlay}" | sed -e 's@/@_@g'`

	ip_to_num_width "$overlay"
	local overlay_raw_ipnum="$RET"
	C_overlay_width="$RET2"

	ip_to_num_width "$underlay"
	local underlay_raw_ipnum="$RET"
	C_underlay_width="$RET2"

	num_to_ip "$underlay_raw_ipnum"
	local underlay_raw_ip="$RET"

	# Mask off the overlay address to the width specified.
	width_to_mask "$C_overlay_width"
	local overlay_ipnum="$(( $overlay_raw_ipnum & $RET ))"

	num_to_ip "$overlay_ipnum"
	C_overlay_subnet="$RET/$C_overlay_width"

	# Strip any insignificant octets on the right to make the shortest prefix.
	RET=${RET%.0}; RET=${RET%.0}; RET=${RET%.0}
	C_overlay_prefix="$RET"

	# The underlay prefix.
	width_to_mask "$C_underlay_width"
	local underlay_prefix_ipnum="$(( $underlay_raw_ipnum & $RET ))"
	num_to_ip "$underlay_prefix_ipnum"
	C_underlay_prefix="$RET"

	C_underlay_subnet="$C_underlay_prefix/$C_underlay_width"

	# Mask off the underlay address to the width specified.
	width_to_mask "$C_underlay_width"
	RET="$(( ~ $RET ))"
	local underlay_overlay_ipnum="$(( $underlay_raw_ipnum & $RET ))"

	# Shift the underlay addresses and merge it with the overlay
	# to make the bridge subnet addressing and from that the name.
	local sl="$(( $C_underlay_width - $C_overlay_width ))"
	local bridge_width="$(( $C_overlay_width + ( 32 - $C_underlay_width ) ))"
	local slice_width="$bridge_width"
	local bridge_ipnum="$(( $overlay_ipnum | ($underlay_overlay_ipnum << $sl) ))"
	local bridge_name_ipnum="$bridge_ipnum"

	case "$C_flag_mode-$C_flag_type" in
	compact-vxlan)
		bridge_name_ipnum="$overlay_ipnum"
		bridge_width="$C_overlay_width"
		;;
	sliced-vxlan)
		bridge_width="$C_overlay_width"
		;;
	compact-ipip)
		bridge_name_ipnum="$overlay_ipnum"
		;;
	esac

	num_to_ip "$bridge_ipnum"
	C_bridge_subnet="$RET/$bridge_width"
	num_to_ip "$(( $bridge_ipnum + 1 ))"
	C_overlay_address="$RET"

	# Addresses and route for the bridge (FLAG: local)
	local n=1
	C_bridge_addresses=''
	while [ "$n" -le "$C_flag_host_reserve" ]
	do
		num_to_ip "$(( $bridge_ipnum + $n ))"
		C_bridge_addresses="$C_bridge_addresses $RET/$bridge_width"
		n="$(( $n + 1 ))"
	done

	# If DHCP is requested, work out address range (FLAG: dhcp)
	if [ "$C_flag_dhcp" = 'y' ]; then
		num_to_ip "$(( $bridge_ipnum + 1 ))"
		C_bridge_dhcp_listen="$RET"

		# DHCP addresses.
		num_to_ip "$(( $bridge_ipnum + ${C_flag_host_reserve} + 1 ))"
		C_bridge_dhcp_low="$RET"

		width_to_mask "$slice_width"
		RET="$(( ~ $RET ))"
		num_to_ip "$(( $bridge_ipnum + (-2 & $RET) ))"
		C_bridge_dhcp_high="$RET"
	fi

	# Work out the bridge name.
	num_to_ip "$bridge_name_ipnum" "-"
	RET=${RET%-0}; RET=${RET%-0}; RET=${RET%-0};
	C_bridge_state="fan-$RET"

	if [ "$C_flag_bridge" != '' ]; then
		C_bridge="$C_flag_bridge"

	else
		C_bridge="$C_bridge_state"
	fi

	# The raw underlay IP address is our local address on the tunnel.
	num_to_ip "$underlay_raw_ipnum"
	C_tun_local="$RET"

	case "$C_flag_type" in
	ipip1)
		# Determine if we have a ftunN associated with this local address.
		local n
		if [ ! -f "$state_dir/map-$C_tun_local" ]; then
			n=0
			while [ -f "$state_dir/alloc-ftun$n" ]; do
				n=$(($n+1))
			done
			echo "$C_tun_local" >"$state_dir/alloc-ftun$n"
			echo "ftun$n" >"$state_dir/map-$C_tun_local"
		fi

		C_tun="`cat "$state_dir/map-$C_tun_local"`"
		;;

	ipip)
		# We use tunl0 for all overlay mappings.
		C_tun="tunl0"
		;;

	vxlan)
		# We need a ftunN per bridge
		local n
		if [ ! -f "$state_dir/map-$C_bridge" ]; then
			n=0
			while [ -f "$state_dir/alloc-ftun$n" ]; do
				n=$(($n+1))
			done
			echo "$C_bridge" >"$state_dir/alloc-ftun$n"
			echo "ftun$n" >"$state_dir/map-$C_bridge"
		fi

		C_tun="`cat "$state_dir/map-$C_bridge"`"
		;;
	esac

	# Work out the device name for the underlay address.
	if [ "$C_flag_i_device" = "" ]; then
		num_to_ip "$underlay_raw_ipnum"
		C_underlay_dev=`ip -4 -o addr show to "$RET" | awk '{ print $2 }'`
	else
		C_underlay_dev="$C_flag_i_device"
	fi
	[ "$C_underlay_dev" ] && C_i_flags="${C_i_flags} --i-device=${C_underlay_dev}"

	case "$C_flag_type" in
	ipip*)	
		C_tun_control="type ipip"
		C_bridge_mtu=1480
		;;
	vxlan)
		# XXX: check that the overlay width is not more than 24 bits.

		# Work out the vxlan ID, which is our overlay >> 8 bits to fix in the
		# vxlan nid.
		local vxlan_id="$(( $overlay_ipnum >> 8 ))"

		C_tun_control="type vxlan id $vxlan_id dev $C_underlay_dev dstport 0"
		C_bridge_mtu=1450
		;;
	esac

	if [ "$C_flag_debug" = 'y' ]; then
		set | grep "^C_"
		exit 1
	fi
}

fail()
{
	[ "$last_cmd" != '' ] && echo "$0: $last_cmd" 1>&2
	echo "$0: $@" 1>&2
	exit 1
}
warn()
{
	[ "$last_cmd" != '' ] && echo "$0: $last_cmd" 1>&2
	echo "$0: WARNING: $@" 1>&2
}
mute()
{
	:
}

slice_down_if_up()
{
	local fail="$1"

	if [ -f "$state_dir/slice-state-$C_slice_id" ]; then
		# If we are using the address for the tunnel route, we need to flip it out.
		rm -f "$state_dir/addr-$C_tun-$C_overlay_prefix-$C_slice_id"
		if [ -f "$state_dir/net-$C_overlay_prefix" ]; then
			local N_overlay_subnet
			local N_tun
			local N_overlay_address

			read N_overlay_subnet N_tun N_overlay_address \
				<"$state_dir/net-$C_overlay_prefix"

			# We are using the address of the bridge which is about to go, so flip to
			# a new one if available.
			if [ "$N_overlay_address" = "$C_overlay_address" ]; then
				N_overlay_address=`cat "$state_dir/addr-$C_tun-$C_overlay_prefix"-* 2>/dev/null | head -1`
				# If we have none, then simply remove the address for now.
				[ "$N_overlay_address" = '' ] && N_overlay_address='0.0.0.0'

				case "$C_flag_type" in
				ipip*)
					run ip route change "$C_overlay_subnet" dev "$C_tun" src "$N_overlay_address" || \
						$fail "$C_tun: failed to switch master route address"
					;;
				esac
				echo "$N_overlay_subnet $N_tun $N_overlay_address" \
					>"$state_dir/net-$C_overlay_prefix"
			fi
		fi

		local bridge_address
		for bridge_address in $C_bridge_addresses
		do
			run ip addr del "$bridge_address" dev "$C_bridge" || \
				"$fail" "$C_bridge: failed to remove $bridge_address address"
		done

		run iptables -t nat -D POSTROUTING --source "$C_bridge_subnet" -j "fan-egress" || \
			$fail "$C_bridge: unable to destroy NAT for bridge (POSTROUTING)"
		run iptables -t nat -D "fan-egress" -j SNAT --source "$C_bridge_subnet" --to "$C_tun_local" || \
			$fail "unable to destroy NAT for bridge (SNAT)"

		rm -f "$state_dir/slice-state-$C_slice_id"
		rm -f "$state_dir/slice-display-$C_slice_id"
	fi
}

bridge_down_if_free()
{
	local fail="$1"

	[ ! -f "$state_dir/brg-state-$C_bridge" ] && return

	slices=`cat "$state_dir/slice-state"-* 2>/dev/null | grep "^$C_bridge " | wc -l`
	if [ "$slices" -eq 0 ]; then
		run ip link set dev "$C_bridge" down || \
			$fail "$C_bridge: failed to bring interface down"
		if ! run brctl delbr "$C_bridge"; then
			$fail "$C_bridge: failed destroy bridge interface"
		else
			rm -f "$state_dir/brg-state-$C_bridge"
		fi
	fi
}

route_down_if_free()
{
	local fail="$1"

	local N_overlay_subnet
	local N_tun
	local N_overlay_address

	[ ! -f "$state_dir/net-$C_overlay_prefix" ] && return

	read N_overlay_subnet N_tun N_overlay_address \
		<"$state_dir/net-$C_overlay_prefix"

	if [ "$N_overlay_address" = "0.0.0.0" ]; then
		case "$C_flag_type" in
		ipip*)
			run ip route del "$C_overlay_subnet" dev "$C_tun" || \
				$fail "$C_tun: failed to remove master route"
			;;
		esac
		run iptables -t nat -D "fan-egress" --dest "$C_overlay_subnet" -j RETURN || \
			$fail "$C_tun: failed to remove master route NAT"
			
		rm -f "$state_dir/net-$C_overlay_prefix"
	fi
}

tun_down_if_free()
{
	local fail="$1"

	[ ! -f "$state_dir/tunnel-$C_tun" ] && return

	mappings=`ls -1 "$state_dir/addr-$C_tun-$C_overlay_prefix"-* 2>/dev/null | wc -l`
	if [ "$mappings" -eq 0 ]; then
		case "$C_flag_type" in
		ipip*)
			# Note: this is will _after_ removing the last fan mapping, exiting
			# EINVAL.  Therefore while this is investigated, ignore any failures.
			run ip link change dev "$C_tun" $C_tun_control fan-map "$C_overlay_subnet:0/0" 2>/dev/null
			;;
		esac
		rm -f "$state_dir/tunnel-$C_tun-$C_overlay_prefix"
	fi

	mappings=`ls -1 "$state_dir/tunnel-$C_tun"-* 2>/dev/null | wc -l`
	if [ "$mappings" -eq 0 ]; then
		run ip link set dev "$C_tun" down || \
			$fail "$C_tun: failed to down interface"
		case "$C_flag_type" in
		ipip1|vxlan)
			run ip link delete "$C_tun" $C_tun_control || \
				$fail "$C_tun: unable to destroy address translator"
		esac
		rm -f "$state_dir/tunnel-$C_tun"

		# Deallocate this tunnel allowing its reuse.
		if [ -f "$state_dir/alloc-$C_tun" ]; then
			local T_map_name
			read T_map_name <"$state_dir/alloc-$C_tun"
			
			rm -f "$state_dir/map-$T_map_name"
			rm -f "$state_dir/alloc-$C_tun"
		fi
	fi
}


dhcp_reconfigure()
{
	local fail="$1"

	local dhcp_state
	local dhcp_flags
	local dhcp_flags_current

	dhcp_flags=`
		for dhcp_state in "$state_dir/slice-dhcp"-*
		do
			[ "$dhcp_state" = "$state_dir/slice-dhcp-*" ] && continue
			read dhcp_bridge dhcp_listen dhcp_low dhcp_high <"$dhcp_state"

			echo "--listen-address $dhcp_listen --dhcp-range $dhcp_low,$dhcp_high"
		done
	`
	dhcp_flags_current=`cat "$state_dir/dnsmasq-flags-$C_bridge_state" 2>&1`

	# Unchanged, status quo.
	if [ "$dhcp_flags_current" = "$dhcp_flags" ]; then
		return
	fi

	# Kill off the current dnsmasq, leaving its state files for reuse.
	dhcp_pid=`cat "$state_dir/dnsmasq-$C_bridge_state.pid" 2>/dev/null`
	if [ "$dhcp_pid" ]; then
		kill "$dhcp_pid" 2>/dev/null
		while kill -0 "$dhcp_pid" 2>/dev/null
		do
			sleep 0.1		# XXX: this really needs to timeout.
		done
	fi
	rm -f "$state_dir/dnsmasq-$C_bridge_state.pid"
	rm -f "$state_dir/dnsmasq-flags-$C_bridge_state"

	if [ "$dhcp_flags" = '' ]; then
		return
	fi

	echo "$dhcp_flags" >"$state_dir/dnsmasq-flags-$C_bridge_state"

	for DNSMASQ_USER in fan-dnsmasq dnsmasq nobody
	do
	if getent passwd ${DNSMASQ_USER} >/dev/null; then
		break
	fi
	done

	run dnsmasq -u ${DNSMASQ_USER} \
		--strict-order \
		--bind-interfaces \
		--pid-file="$state_dir/dnsmasq-$C_bridge_state.pid" \
		--conf-file= \
		$dhcp_flags \
		--dhcp-no-override \
		--except-interface=lo \
		--interface="$C_bridge" \
		--dhcp-leasefile=/var/lib/misc/dnsmasq."$C_bridge_state".leases \
		--dhcp-authoritative \
	    || $fail "$C_bridge: failed to start dnsmasq"

}

dhcp_down_if_up()
{
	local fail="$1"

	if [ -f "$state_dir/slice-dhcp-$C_slice_id" ]; then
		rm -f "$state_dir/slice-dhcp-$C_slice_id"

		dhcp_reconfigure "$fail"
	fi
}

nat_down_if_free()
{
	local fail="$1"

	slices=`ls -1 "$state_dir/slice"-* 2>/dev/null | wc -l`
	if [ "$slices" -eq 0 ]; then
		run iptables -t nat -D "fan-egress" -o lo0 -j RETURN || \
			$fail "unable to deconfigure NAT core (lo0 exception)"
		run iptables -t nat -X "fan-egress" || \
			$fail "unable to deconfigure NAT core (destroy chain)"
		rm "$state_dir/nat-core"
	fi
}

fail_up()
{
	echo "$0: $last_cmd" 1>&2
	echo "$0: WARNING: $@" 1>&2
	slice_down_if_up mute
	bridge_down_if_free mute
	route_down_if_free mute
	tun_down_if_free mute
	dhcp_down_if_up mute
	nat_down_if_free mute
	exit 1
}

cmd_up_help()
{
	echo "Usage: $0 up -u <underlay> -o <overlay> [<options>...]" 1>&2
	echo "       $0 up -a" 1>&2
}
cmd_up()
{
	if [ "$#" -eq 0 ]; then
		cmd_up_help
		exit 1
	fi

	### HANDLE LECAGY HERE BY CALLING SELF AGAIN
	cmd_decode_init
	if ! cmd_decode_all "up" "$@"; then
		TEMP=$(cmd_decode_legacy "up" "$@")
		eval set -- "$TEMP"
		cmd_up "$@"
		return
	fi

	# XXX: this likely should be just spinning all addresses if we have
	#      no underlay address.  This would allow us to say like:
	#          fanctl up -o 15.0.0.0/8

	#networks_decode_addresses "$C_overlay" "$C_underlay"
	underlay_lookup_address "$C_underlay"

	# XXX: we should be checking we have at least some matching
	#      addresses.
	L_overlay="$C_overlay"
	##L_underlays="$RET"

	# When the caller indicates that they want this brought up in
	# --auto mode they are saying they want it brought up as if
	# it was brought up by 'fanctl up -a' which in turn means
	# they only want enabled Fan Networks brought up.  Use
	# an appropriate selector for this case.
	if [ "$C_flag_auto" = 'y' ]; then
		selector='__cmd_up_all_select'
	else
		selector='__cmd_up_select'
	fi
	ret=0
	for L_underlay in $RET
	do
		if ! config_scan "$selector" __cmd_up "$@"; then
			(__cmd_up "$@" -u "$L_underlay")
			res="$?"
			if [ "$res" -ne 0 ]; then
				echo "$0: up $@ -- failed err=$res"
			fi
			ret="$res"
		else
			# config_scan has processed something, the status
			# is in $RET. Pick up errors.
			if [ "$RET" -gt 0 ]; then
				ret="$RET"
			fi
		fi
	done
	
	exit "$ret"
}
__cmd_up_select()
{
	#echo "<<<$@>>>"
	local overlay="$1"
	local underlay="$2"
	#local flags="$3"

	#echo "L_overlay<$L_overlay> L_underlay<$L_underlay> overlay<$overlay> underlay<$underlay>"

	if [ "$L_overlay" != '' -a "$L_overlay" != "$overlay" ]; then
		return 1
	fi

	if [ "$L_underlay" = "" ]; then
		return 0
	fi

	# See if any of our direct addresses match this entry.
	if [ "$L_underlay" = "$underlay" ]; then
		RET="$underlay"
		return 0
	fi

	# See if the underlay address is in this mask.
	ip_to_num_width "$underlay"
	local ipnum="$RET"
	local width="$RET2"

	width_to_mask "$width"
	local address_mask="$RET"
	local address_ipnum
	local address_ipnum_prefix
	local address_prefix

	address_prefix="$(( $ipnum & $address_mask ))"
	# If an address on the network was specified find exactly that.
	if [ "$ipnum" -ne "$address_prefix" ]; then
		address_prefix="$ipnum"
		address_mask="$(( ~0 ))"
	fi

	local address="$L_underlay"

	ip_to_num_width "$address"
	address_ipnum="$RET"
	address_ipnum_prefix="$(( $RET & $address_mask ))"

	# XXX: should we be checking the two widths match if both present?

	# If the address offered has no width then use the mask width.
	case "$address" in
	*/*)	;;
	*)	address="$address/$width" ;;
	esac
	
	if [ "$address_ipnum_prefix" -eq "$address_prefix" ]; then
		RET="$address"
		return 0
	fi
	
	return 1
}
__cmd_up()
{
	#echo "__cmd_up<$@>"
	networks_decode_one "$@"

	# Validation: ensure the bridge is not already configured.
	[ -f "$state_dir/slice-state-$C_slice_id" ] && fail "$C_bridge: already configured"

	# Validation: check the flag combinations make sense.
	case "$C_flag_mode-$C_flag_type" in
	sliced-vxlan)
		[ -f "$state_dir/net-$C_overlay_prefix" ] && fail "$C_underlay $C_overlay: cannot configure multiple sliced vxlan bridges on the same overlay"
		;;
	esac

	# Record this slice as up and using this bridge.
	echo "$C_bridge $C_overlay $C_underlay -- $@ $C_i_flags" >"$state_dir/slice-state-$C_slice_id"
	#echo "$C_bridge $C_overlay $C_underlay $C_user_flags" >"$state_dir/slice-display-$C_slice_id"
	# Record this address as available to the tunnel should it need it.
	echo "$C_overlay_address" >"$state_dir/addr-$C_tun-$C_overlay_prefix-$C_slice_id"

	# create the bridge
	local bridge_created=0
	if [ ! -f "$state_dir/brg-state-$C_bridge" ]; then
		run brctl addbr "$C_bridge" || fail_up "$C_bridge: failed to create bridge"
		#echo "$C_bridge $C_overlay $C_underlay$C_flags" >"$state_dir/bridge-$C_tun-$C_overlay_prefix-$C_bridge_state"
		echo "" >"$state_dir/brg-state-$C_bridge"
		run ip link set dev "$C_bridge" mtu "$C_bridge_mtu" || \
			fail_up "$C_bridge: failed to bring interface up"
		echo 1 >"/proc/sys/net/ipv4/conf/$C_bridge/promote_secondaries"
		bridge_created=1
	fi

	# ensure the tunnel is up.
	if [ ! -f "$state_dir/tunnel-$C_tun" ]; then
		case "$C_flag_type" in
		ipip1)
			run ip link add "$C_tun" $C_tun_control local "$C_tun_local" underlay "$C_underlay_prefix" || \
				fail_up "$C_tun: failed to configure address translation"
			;;
		vxlan)
			run ip link add "$C_tun" $C_tun_control local "$C_tun_local" fan-map "$C_overlay_subnet:$C_underlay_subnet" || \
				fail_up "$C_tun: failed to configure address translation"
			;;
		esac
		run ip link set dev "$C_tun" up || \
			fail_up "$C_tun: failed to up interface"
		echo "" >"$state_dir/tunnel-$C_tun"
	fi

	# ensure that address tunnelling is enabled for 15 net
	if [ ! -f "$state_dir/tunnel-$C_tun-$C_overlay_prefix" ]; then
		case "$C_flag_type" in 
		ipip)
			run ip link change dev "$C_tun" $C_tun_control fan-map "$C_overlay_subnet:$C_underlay_subnet" || \
				fail_up "$C_tun: failed to configure address translation"
			;;
		vxlan)
			run brctl addif "$C_bridge" "$C_tun" || \
				fail_up "$C_tun: failed to add vxlan interface to bridge"
			;;
		esac
		echo "$C_tun $C_tun_local $C_overlay_subnet" >"$state_dir/tunnel-$C_tun-$C_overlay_prefix"
	fi

	# Bring up the nat core rules
	if [ ! -f "$state_dir/nat-core" ]; then
		run iptables -t nat -N "fan-egress" || \
			fail_up "unable to initialise NAT core (new chain)"
		echo "" >"$state_dir/nat-core"
		run iptables -t nat -I "fan-egress" -o lo0 -j RETURN || \
			fail_up "unable to initialise NAT core (lo0 exception)"
	fi

	# enable SNAT for packets leaving the FANs
	run iptables -t nat -A POSTROUTING --source "$C_bridge_subnet" -j "fan-egress" || \
		fail_up "$C_bridge: unable to initialise NAT for bridge (POSTROUTING)"
	run iptables -t nat -A "fan-egress" -j SNAT --source "$C_bridge_subnet" --to "$C_tun_local" || \
		fail_up "unable to initialise NAT for bridge (SNAT)"

	# Add the local addressses, do this after any bridge addif occurs as that
	# strips the addresses.
	# NOTE: we are relying on the add being a one time deal per bridge else we will
	#       lose addresses.
	local bridge_address
	for bridge_address in $C_bridge_addresses
	do
		run ip addr add "$bridge_address" dev "$C_bridge" || \
			fail_up "$C_bridge: failed to add $bridge_address address"
	done

	# Delay bringing the bridge up to allow addresses to be added reliably.
	if [ "$bridge_created" -eq 1 ]; then
		run ip link set dev "$C_bridge" up || \
			fail_up "$C_bridge: failed to bring interface up"
	fi

	# ensure that routing is present for 15 net outgoing
	if [ ! -f "$state_dir/net-$C_overlay_prefix" ]; then
		case "$C_flag_type" in
		ipip*)
			run ip route add "$C_overlay_subnet" dev "$C_tun" src "$C_overlay_address" || \
				fail_up "$C_tun: failed to add master route"
			;;
		esac
		echo "$C_overlay_subnet $C_tun $C_overlay_address" \
			>"$state_dir/net-$C_overlay_prefix"
		# If we are routing to this FAN then we do not need to NAT
		run iptables -t nat -I "fan-egress" --dest "$C_overlay_subnet" -j RETURN || \
			fail "$C_tun: failed to add master route NAT"
	fi

	# Ensure we have ip_forwarding on.
	echo 1 > /proc/sys/net/ipv4/ip_forward

	# If dhcp is requested then we need to ensure the current dnsmasq is correctly
	# reconfigured for this new range.
	if [ "$C_flag_dhcp" = 'y' ]; then
		echo "${C_bridge} ${C_bridge_dhcp_listen} ${C_bridge_dhcp_low} ${C_bridge_dhcp_high}" > "$state_dir/slice-dhcp-$C_slice_id"

		dhcp_reconfigure fail_up
	fi
}

config_scan()
{
	local select="$1"
	local payload="$2"
	shift 2

	# No config is fine.
	if [ ! -e "/etc/network/fan" ]; then
		return 1
	fi

	lock -x || fail "unable to lock fan state"

	local n=0
	local err=0
	local found=1
	local underlay_actual
	local config
	local lconfig
	while read line
	do
		n="$((n + 1))"

		line="${line%%#*}"
		read underlay overlay flags <<EOL
$line
EOL
		[ "$underlay" = "" ] && continue

		#echo "APW config underlay<$underlay> overlay<$overlay> L_underlay<$L_underlay"

		# Check if we have any local config before selection.
		config_filename "${underlay}" "${overlay}" "${underlay}"
		config="$RET"
		lconfig=''
		if [ -f "$config" ]; then
			lconfig=$(cat "$config")
		fi
		# XXX: this should be passed in as a real parameter ... sigh.
		config_filename "${underlay}" "${overlay}" "${L_underlay}"
		config="$RET"
		if [ -f "$config" ]; then
			lconfig="$lconfig $(cat "$config")"
		fi
		#echo "LCONFIG<$lconfig> config<$config>"

		# Run this in a subshell so we catch its exit.

		# See if we want this line.
		! $select $overlay $underlay "$lconfig $flags" && continue
		underlay_actual="$RET"

		found=0

		($payload $flags $lconfig "$@" -o "$overlay" -u "$underlay_actual")
		res="$?"

		if [ "$res" -ne 0 ]; then
			echo "$0: /etc/network/fan:$n $underlay $overlay $flags -- failed err=$res"
			err="$res"
		fi
	done <"/etc/network/fan"

	RET="$err"
	return "$found"
}

slices_scan()
{
	local why="$1"
	local select="$2"
	local payload="$3"
	shift 3
		
	lock -x || fail "unable to lock fan state"

	err=0
	found=1
	for state in "$state_dir/slice-state"-*
	do
		[ "$state" = "$state_dir/slice-state-*" ] && continue
		read bridge overlay underlay specifier flags <"$state"

		# See if we want this line.
		! $select "$@" $bridge $overlay $underlay "$flags" && continue

		found=0

		(
			networks_decode_one $flags -o "$overlay" -u "$underlay"
			$payload "$overlay" "$underlay" $flags
		)
		res="$?"

		if [ "$res" -ne 0 ]; then
			echo "$0: $why $overlay $underlay -- failed err=$res"
			err="$res"
		fi
	done

	RET="$err"
	return $found
}

__cmd_up_all_select()
{
	#echo "__cmd_up_all_select($@)"
	#local overlay="$1"
	#local underlay="$2"
	local flags="$3"

	case " $flags " in
	*\ --enable\ *)	;;
	*\ --on\ *)	;;
	*)		return 1 ;;
	esac

	__cmd_up_select "$@"
}

cmd_up_all()
{
	for L_underlay in $(
			ip -4 -o addr show | \
			while read x iface which addr x
			do
				case "$which" in
				inet)		;;
				*)		continue ;;
				esac
				addr="${addr%/*}"

				echo "$addr"
			done
		)
	do
		#echo "L_underlay<$L_underlay>"
		config_scan __cmd_up_all_select __cmd_up '--auto'
	done
	exit "$RET"
}

cmd_net_up()
{
	local dev="$1"

	RET="0"
	for L_underlay in $(
			ip -4 -o addr show dev "$dev" | \
			while read x iface which addr x
			do
				case "$which" in
				inet)		;;
				*)		continue ;;
				esac
				addr="${addr%/*}"

				echo "$addr"
			done
		)
	do
		config_scan __cmd_up_all_select __cmd_up '--auto'
	done
	exit "$RET"
}

cmd_down_help()
{
	echo "Usage: $0 down -u <underlay> -o <overlay>" 1>&2
	echo "       $0 down -a" 1>&2
	echo "       $0 down -e" 1>&2
}
cmd_down()
{
	if [ "$#" -eq 0 ]; then
		cmd_down_help
		exit 1
	fi

	cmd_decode_init
	if ! cmd_decode_ou "down" "$@"; then
		TEMP=$(cmd_decode_legacy "down" "$@")
		eval set -- "$TEMP"
		cmd_down "$@"
		return
	fi

	#networks_decode_addresses "$C_overlay" "$C_underlay"
	underlay_lookup_address "$C_underlay"

	L_overlay="$C_overlay"
	L_underlays="$RET"

	if ! slices_scan 'down' __cmd_down_select __cmd_down_payload; then
		fail "$C_overlay $C_underlay: not configured"
		RET="1"
	fi
	exit "$RET"
}
__cmd_down_select()
{
	local bridge="$1"
	local overlay="$2"
	local underlay="$3"

	#echo "APW: overlay<$overlay> underlay<$underlay> L_overlay<$L_overlay> L_underlays<$L_underlays>"

	if [ "$L_underlays" = "" ]; then
		return 1
	fi

	for select_underlay in $L_underlays
	do
		if [ "$select_underlay" = "$underlay" -a "$L_overlay" = "$overlay" ]; then
			return 0
		fi
	done
	return 1
}
__cmd_down_payload()
{
	# Validation: ensure the bridge is already configured.
	[ ! -f "$state_dir/slice-state-$C_slice_id" ] && fail "XXX: $C_bridge: not configured"

	# XXX: not the right check now, we may not have one either.
	# Validation: confirm the bridge is not in use.
	count=`ls /sys/class/net/"$C_bridge"/brif 2>/dev/null | \
		egrep -v "^$C_tun\$" | \
		wc -l`
	[ "$count" != 0 ] && \
		fail "$C_bridge: in use, will not destroy"
	
	# if dnsmasq is present for this network terminate it
	dhcp_down_if_up fail

	slice_down_if_up fail

	# remove routing for 15.0.1.0/24 from the bridge
	# destroy bridge fan-15-0-1
	bridge_down_if_free fail

	# if this is the last bridge using 15 net then:
	#  clear out routing
	#  drop address tunnelling
	route_down_if_free warn
	tun_down_if_free warn
	nat_down_if_free warn
}


cmd_down_all_auto()
{
	slices_scan 'down' __cmd_down_select_auto __cmd_down_payload
	exit "$RET"
}
__cmd_down_select_auto()
{
	#local bridge="$1"
	#local underlay="$2"
	#local overlay="$3"
	local flags="$4"

	case " $flags " in
	*\ --auto\ *)	return 0 ;;
	*)		return 1 ;;
	esac
}

cmd_down_all_full()
{
	slices_scan 'down' true __cmd_down_payload
	exit "$RET"
}

cmd_net_down()
{
	L_underlay_dev="$1"

	slices_scan 'down' __cmd_net_down_select __cmd_net_down_payload
	exit "$RET"
}
__cmd_net_down_select()
{
	#local bridge="$1"
	#local underlay="$2"
	#local overlay="$3"
	local flags="$4"

	case " $flags " in
	*\ _dev\ $L_underlay_dev\ *) ;;
	*)		return 1 ;;
	esac
	case " $flags " in
	*\ auto\ *)	return 0 ;;
	*)		return 1 ;;
	esac
}
__cmd_net_down_payload()
{
	C_underlay_dev="$L_underlay_dev"
	__cmd_down_payload "$@"
}

cmd_show_help()
{
	echo "Usage: $0 show" 1>&2
}
cmd_show()
{
	if [ "$#" -ne 0 ]; then
		cmd_show_help
		exit 1
	fi

	printf "%-16s %-20s %-20s %s\n" 'Bridge' 'Underlay' 'Overlay' 'Flags'
	lock -s || exit 0
	for state in "$state_dir/bridge"-* "$state_dir/slice-state"-*
	do
		[ "$state" = "$state_dir/bridge-*" ] && continue
		[ "$state" = "$state_dir/slice-state-*" ] && continue
		read bridge overlay underlay separator flags <"$state"
		#echo "<$overlay> <$underlay> <$flags>"
		cmd_decode_init
		cmd_decode_internal $flags
		cmd_decode_show $flags
		printf "%-16s %-20s %-20s%s\n" $bridge $C_underlay $C_overlay "$RET"
	done
}

#
# CMD: config set -u <underlay> -o <overlay> [<option>...]
# CMD: config show -u <underlay> -o <overlay>
# CMD: config list
#
cmd_config_help()
{
	echo "Usage: $0 config set -u <underlay> -o <overlay> [<options>...]" 1>&2
	echo "       $0 config show -u <underlay> -o <overlay>" 1>&2
	echo "       $0 config list" 1>&2
}

config_filename()
{
	local underlay="$1"
	local overlay="$2"
	local interface="$3"

	local interface_suffix=''

	local underlay_ipnum
	local underlay_width
	local underlay_mask

	local interface_ipnum
	local interface_width
	local interface_mask

	# Round the underlay address to the mask.
	ip_to_num_width "$underlay"
	underlay_ipnum="$RET"
	underlay_width="$RET2"
	width_to_mask "$underlay_width"
	underlay_mask="$RET"

	if [ "$(( $underlay_ipnum & ~$underlay_mask ))" -ne 0 ]; then
		num_to_ip "$(( $underlay_ipnum & $underlay_mask ))"
		underlay="$RET/$underlay_width"
	fi

	# Work out if the host portion of the interface address is 0.
	case "$interface" in
	*/*)    ;;
	*)      interface="$interface/$underlay_width" ;;
	esac
	ip_to_num_width "$interface"
	interface_ipnum="$RET"
	interface_width="$RET2"
	width_to_mask "$interface_width"
	interface_mask="$RET"

	if [ "$(( $interface_ipnum & ~$interface_mask ))" -ne 0 ]; then
		num_to_ip "$interface_ipnum"
		interface_suffix="--${RET}"
	fi

	RET="$lconfig_dir/$(echo "${underlay}--${overlay}${interface_suffix}" | sed -e 's@/@-@g').conf"
}

cmd_config()
{
	if [ "$#" -lt 1 ]; then
		cmd_config_help
		exit 1
	fi

	local cmd="$1"
	shift

	case "$cmd" in
	list|ls)
		ls -1 "$lconfig_dir" | \
		while read config
		do
			case "$config" in
			*.conf)		;;
			*)		continue ;;
			esac

			config=$( echo "$config" | sed \
				-e 's/.conf$//' \
				-e 's/--/ /g' \
				-e 's@-@/@g'
			)
			echo "$config"
		done
		;;
	show)
		cmd_decode_init
		if ! cmd_decode_ou "config set" "$@"; then
			fail "invalid config"
		fi
		if [ "$C_underlay" = '' -o "$C_overlay" = '' ]; then
			fail "underlay/overlay required"
		fi
		config_filename "${C_underlay}" "${C_overlay}" "${C_underlay}"
		config="$RET"
		uconfig="$config-user"
		[ -f "$uconfig" ] && cat "$uconfig"
		;;
	set)
		cmd_decode_init
		if ! cmd_decode_config "config set" "$@"; then
			fail "invalid config"
		fi
		if [ "$C_underlay" = '' -o "$C_overlay" = '' ]; then
			fail "underlay/overlay required"
		fi
		config_filename "${C_underlay}" "${C_overlay}" "${C_underlay}"
		config="$RET"
		#config="$lconfig_dir/$(echo "${C_underlay}--${C_overlay}" | sed -e 's@/@-@g').conf"
		uconfig="$config-user"
		cmd_decode_user "$@"
		#echo "@<$@> RET<$RET>"
		if [ "$RET" = "" ]; then
			rm -f "$config" "$uconfig"
		else
			echo "$RET" >"$config"
			echo "$RET2" >"$uconfig"
		fi
		;;
	*)
		cmd_config_help
		exit 1
		;;
	esac
}

cmd_net_help()
{
	echo "Usage: $0 net start <device>" 1>&2
	echo "       $0 net stop <device>" 1>&2
}
cmd_net()
{
	if [ "$#" != 2 ]; then
		cmd_net_help
		exit 1
	fi
	case "$1" in
	start)
		cmd_net_up "$2"
		;;
	stop)
		cmd_net_down "$2"
		;;
	*)
		cmd_net_help
		exit 1
		;;
	esac
}

cmd_help_help()
{
	echo "Usage: $0 help <command>" 1>&2
}
cmd_help()
{
	if [ "$#" != 1 ]; then
		{
			echo "Command summary:"

			cmd_up_help
			echo ""
			cmd_down_help
			echo ""
			cmd_show_help
			echo ""
			cmd_net_help
			echo ""
			cmd_config_help
			echo ""
			cmd_help_help
		} 2>&1 | sed -e '2,$s/Usage:/      /'
		exit 0
	fi
	case "$1" in
	up)
		cmd_up_help
		;;
	down)
		cmd_down_help
		;;
	show)
		cmd_show_help
		;;
	net)
		cmd_net_help
		;;
	config)
		cmd_config_help
		;;
	help)
		cmd_help_help
		;;
	*)
		echo "Unknown command." 1>&2
		exit 1
		;;
	esac

	exit 0
}

cmd__upgrade()
{
	# Check if we even have state to convert.
	[ ! -d "$state_dir" ] && exit 0

	echo "fanctl: converting live state"

	# Needing work:
	#  slice-dhcp-15.0.0.0_8-192.168.122.72_16
	#  slice-display-15.0.0.0_8-192.168.122.72_16
	#  slice-state-15.0.0.0_8-192.168.122.72_16
	#  brg-state-fan-15
	#  dnsmasq-flags-fan-15
	#  addr-ftun0-15-15.0.0.0_8-192.168.122.72_16
	for state in "$state_dir/bridge"-*
	do
		[ "$state" = "$state_dir/bridge-*" ] && exit 0

		read bridge overlay underlay flags <"$state"

		(
			networks_decode_one "$overlay" "$underlay" type ipip mode sliced $flags ## XXX: new flags form

			# Replace the bridge state.
			echo "$C_bridge $C_overlay $C_underlay $C_user_flags" >"$state_dir/slice-display-$C_slice_id"
			echo "$C_bridge $C_overlay $C_underlay $C_flags" >"$state_dir/slice-state-$C_slice_id"
			echo "${C_bridge} ${C_bridge_dhcp_listen} ${C_bridge_dhcp_low} ${C_bridge_dhcp_high}" >"$state_dir/slice-dhcp-$C_slice_id"

			# Mark the bridge as available.
			echo "" >"$state_dir/brg-state-$C_bridge_state"

			# we cannot be sure what the current flags are, but if we have dhcp
			# then record non-blank current flags so that we will restart/stop the
			# server correctly on the first change.
			if [ -f "$state_dir/dnsmasq-$C_bridge_state.pid" ]; then
				echo "__DUMMY__" >"$state_dir/dnsmasq-flags-$C_bridge_state"
			fi

			# See if we have an address recorded for this combination.
			if [ -f "$state_dir/addr-$C_tun-$C_overlay_prefix-$C_bridge_state" ]; then
				mv "$state_dir/addr-$C_tun-$C_overlay_prefix-$C_bridge_state" "$state_dir/addr-$C_tun-$C_overlay_prefix-$C_slice_id"
			fi
		)
		rm "$state"
	done

	# Unchanged:
	#  alloc-ftun0
	#  dnsmasq-fan-15.pid
	#  map-fan-15
	#  nat-core
	#  net-15
	#  tunnel-ftun0
	#  tunnel-ftun0-15
}

# Parse the command line.
opt_v=
while getopts ":vs:" opt
do
        case "$opt" in
	v)		opt_v=1 ;;
	?)		echo "$0: $opt: unknown flag ??" 2>&1; exit 1 ;;
	esac
done
shift $(($OPTIND - 1))

# Validation.
if [ "$#" -lt 1 ]; then
	usage
	exit 1
fi
cmd="$1"
shift

lock()
{
	local mode="$1"

	# Ensure we have a lock file if at all possible.
	[ ! -d "$state_dir" ] && mkdir -p "$state_dir" 2>/dev/null
	[ ! -f "$state_dir/.lock" ] && touch "$state_dir/.lock" 2>/dev/null
	
	[ ! -r "$state_dir/.lock" ] && return 1

	exec 9<"$state_dir/.lock" || return 2
	flock "$1" 9
}

# Validate and execute the command.
case "$cmd" in
up)
	[ `id -u` -ne 0 ] && fail "priviledge to alter network configuration required"
	if [ "$#" -eq 1 -a "$1" = "-a" ]; then
		cmd_up_all
		exit 1
	fi
	lock -x || fail "unable to lock fan state"
	cmd_up "$@"
	;;
down)
	[ `id -u` -ne 0 ] && fail "priviledge to alter network configuration required"
	if [ "$#" -eq 1 -a "$1" = "-a" ]; then
		cmd_down_all_auto
		exit 1
	fi
	if [ "$#" -eq 1 -a "$1" = "-e" ]; then
		cmd_down_all_full
		exit 1
	fi
	lock -x || fail "unable to lock fan state"
	cmd_down "$@"
	;;
net)
	[ `id -u` -ne 0 ] && fail "priviledge to alter network configuration required"
	cmd_net "$@"
	;;
show)
	cmd_show "$@"
	;;
config)
	[ `id -u` -ne 0 ] && fail "priviledge to alter network configuration required"
	lock -x || fail "unable to lock fan state"
	cmd_config "$@"
	;;
__upgrade)
	[ `id -u` -ne 0 ] && fail "priviledge to alter network configuration required"
	lock -x || fail "unable to lock fan state"
	cmd__upgrade
	;;
help)
	cmd_help "$@"
	;;
*)
	usage
	echo "$cmd: unknown command" 1>&2
	exit 1
	;;
esac