#!/bin/sh

. /lib/functions.sh

configure() {
	local proto
	local peerip
	local otherpeers
	local fields="
		proto
		port
		vid
		ttl
		tos
		mtu
		macaddr
		zone
		rxcsum
		txcsum
		srcportmin
		srcportmax
		ageing
		maxaddress
		learning
		rsc
		proxy
		l2miss
		l3miss
		gbp
		tunlink
		ipaddr
		ip6addr
	"

	# cleanup old vxmesh and peer entries
	uci -q delete network.vxmesh0
	while uci -q delete network.@vxlan_peer[-1]; do :; done

	# remove vxmesh0 entry from the client bridge and remove extra whitespaces
	uci set network.client.ifname="$(uci -q get network.client.ifname | sed s/vxmesh0// | xargs)"

	# reset dns to authorative
	uci set dhcp.@dnsmasq[0].authoritative="1"

	# check if a vxmesh config is available, otherwise quit
	uci -q get gateway.@vxmesh[0] > /dev/null || return 0

	# check if proto is set and probe for the correct peer ip
	proto="$(uci -q get gateway.@vxmesh[0].proto)"
	case "$proto" in
		vxlan6)
			peerip="$(uci -q get gateway.@gateway[0].peer_ip6)"
			;;
		vxlan)
			peerip="$(uci -q get gateway.@gateway[0].peer_ip)"
			;;
		*)
			echo "FATAL: vxmesh: option proto 'vxlan|vxlan6' required!"
			return 1
			;;
	esac

	# vxmesh needs a separate peer ip as the ip on the client interface ip
	# might be shared over multiple devices
	[ -z "$peerip" ] && {
		echo "FATAL: vxmesh: peer_ip|peer_ip6 required!"
		return 1
	}

	uci -q get gateway.@vxmesh[0].vid > /dev/null || {
		echo "FATAL: vxmesh: missing vid!"
		return 1
	}

	# copy main options over
	uci set network.vxmesh0="interface"
	for option in $fields; do
		uci set network.vxmesh0."$option"="$(uci -q get gateway.@vxmesh[0]."$option")"
	done

	# exclude peerip from the local router, so packets aren't sent to itself
	otherpeers=$(uci -q get gateway.@vxmesh[0].peer | xargs -n1 | grep -v -e "$peerip")

	for peer in $otherpeers; do
		# create peer sections
		if ! uci -q batch > /dev/null; then
			echo "FATAL: vxmesh: error setting up peer!"
			echo "       peer: \"$peer\""
			return 1
		fi <<- EOF
			add network vxlan_peer
			set network.@vxlan_peer[-1].vxlan="vxmesh0"
			set network.@vxlan_peer[-1].dst="$peer"
		EOF
	done

	# learn routes to other peers only over babel interfaces with sufficient mtu
	#   - according to the rfc, vxlan packets must not be fragmented by a VTEP
	#   - the vxlan tunnel requires an mtu of 1570 when using ipv6
	#
	#  -> to avoid sending too large packets over an interface with too small mtu,
	#     don't learn a route to a peer over that interface in the first place
	babel_filter_mtu() {
		local config="$1"
		local otherpeers="$2"
		local mtu
		local ifname

		case $config in
			babelpeer*) ;;
			wireguardpeer*) ;;
			*) return ;;
		esac

		config_get mtu "$config" mtu
		config_get ifname "$config" ifname

		[ "${mtu:-0}" -ge "1570" ] && return
		[ -z "${ifname}" ] && {
			echo "WARNING: could not determine ifname from \"$config\""
			return
		}
		for peer in $otherpeers; do
			if ! uci -q batch > /dev/null; then
				echo "FATAL: error adding babel filter for vxlan peer!"
				echo "       peer: \"$peer\""
				echo "       interface: \"$ifname\""
				return 1
			fi <<- EOF
				add babeld filter
				set babeld.@filter[-1].type="in"
				set babeld.@filter[-1].ip="$peer"
				set babeld.@filter[-1].if="$ifname"
				set babeld.@filter[-1].addedbyautoconfig="true"
				set babeld.@filter[-1].action="deny"
			EOF
		done
	}

	config_load network
	config_foreach babel_filter_mtu interface "$otherpeers"

	# with multiple routers in the network, there shouldn't be an authoritative
	# dhcp server
	uci set dhcp.@dnsmasq[0].authoritative="0"

	# add the vxlan interface to the client bridge
	uci set network.client.ifname="$(uci -q get network.client.ifname) vxmesh0"
}

apply() {
	uci commit network
	uci commit dhcp
	uci commit babeld
}

revert() {
	uci revert network
	uci revert dhcp
	uci revert babeld
}