#!/bin/sh
#
# Copyright (C) 2021 TDT AG <development@tdt.de>
#
# This is free software, licensed under the GNU General Public License v2.
# See https://www.gnu.org/licenses/gpl-2.0.txt for more information.
#

. /lib/functions.sh
. /lib/functions/network.sh
. /usr/share/libubox/jshn.sh

IIF=1000
FWMARK=2000
ID=0

usage() {
	local status="$1"
	local msg="$2"
	if [ -n "$msg" ]; then
		echo "$msg"
		echo ""
	fi
	echo "Usage: $(basename "$0") <command>"
	echo "command:"
	echo "  diag:   diagnostic commands"
	echo "  ipset:  ipset commands"
	echo ""
	echo "diag <command> <iface>"
	echo "command:"
	echo "  gateway <iface>:   ping interface gateway"
	echo "  tracking <iface>:  ping interface tracking targets"
	echo "  rules <iface>:     check interface routing rules"
	echo "  routes <iface>:    check interface routing tables"
	echo ""
	echo "ipset <command>"
	echo "command:"
	echo "  dump:     show all configured ipset names"

	exit "$status"
}

diag_gateway() {
	local iface="$1"

	local gw

	network_get_gateway gw "${iface}"
	[ -z "$gw" ] && network_get_gateway gw "${iface}_4"

	[ -z "$gw" ] && {
		echo "No gateway for interface ${iface} found."
		exit 2
	}

	mwan3 use "$iface" "ping" "-c" "5" "-W" "1" "$gw"
}

diag_tracking() {
	local iface="$1"

	checkips() {
		local ip="$1"
		local iface="$2"

		mwan3 use "$iface" "ping" "-c" "5" "-W" "1" "$ip"
	}

	config_load mwan3
	config_list_foreach "$iface" "track_ip" checkips "$iface"
}

iface_number() {
	local cfg="$1"
	local iface="$2"

	let number++

	[ "$cfg" = "$iface" ] && {
		ID="$number"
	}
}

diag_rules() {
	local iface="$1"

	local number=0
	local iif=0
	local fwmark=0

	local iif_rule iif_result
	local fwmark_rule fwmark_result

	config_load mwan3
	config_foreach iface_number 'interface' "$iface"

	[ "$ID" = "0" ] && {
		echo "Unable to get mwan3 interface number for \"$iface\"."
		exit 2
	}

	let "iif=$IIF+$ID"
	let "fwmark=$FWMARK+$ID"

	iif_rule="$(ip rule | grep ${iif})"
	iif_result="$?"

	fwmark_rule="$(ip rule | grep ${fwmark})"
	fwmark_result="$?"

	if [ "$fwmark_result" = 0 ] && [ "$iif_result" = 0 ]; then
		echo "All required IP rules for interface \"$iface\" found"
		echo "$fwmark_rule"
		echo "$iif_rule"
	elif [ "$fwmark_result" = 1 ] && [ "$iif_result" = 0 ]; then
		echo "Only iif IP rule for interface \"$iface\" found"
		echo "$iif_rule"
	elif [ "$fwmark_result" = 0 ] && [ "$iif_result" = 1 ]; then
		echo "Only fwmark IP rule for interface \"$iface\" found"
		echo "$fwmark_rule"
	else
		echo "Missing fwmark and iif IP rule for interface \"$iface\""
	fi
}

diag_routes() {
	local iface="$1"

	local table table_result

	config_load mwan3
	config_foreach iface_number 'interface' "$iface"

	[ "$ID" = "0" ] && {
		echo "Unable to get mwan3 interface number for \"$iface\"."
		exit 2
	}

	table="$(ip route list table $ID)"
	table_result="$?"

	if [ "$table_result" = 0 ]; then
		echo "Routing table \"$ID\" for interface \"$iface\" found"
		echo "$table"
	else
		echo "Routing table \"$ID\" for interface \"$iface\" not found"
	fi
}

diag_cmd() {
	case "$1" in
		gateway)
			diag_gateway "$2"
			;;
		tracking)
			diag_tracking "$2"
			;;
		rules)
			diag_rules "$2"
			;;
		routes)
			diag_routes "$2"
			;;
		*)
			usage "1" "Command not supported"
			;;
	esac
}

ipset_dump() {
	ipset -n -L 2>/dev/null | grep -v mwan3_ | sort -u
}

ipset_cmd() {
	case "$1" in
		dump)
			ipset_dump
			;;
		*)
			usage "1" "Command not supported"
			;;
	esac
}

main () {
	case "$1" in
		diag)
			diag_cmd "$2" "$3"
			;;
		ipset)
			ipset_cmd "$2"
			;;
		*)
			usage "1" "Command not supported"
			;;
	esac
}

main "$@"