#!/bin/sh /etc/rc.common
# vim: set noexpandtab tabstop=4 shiftwidth=4 softtabstop=4 :

# shellcheck disable=SC2034
START=90
# shellcheck disable=SC2034
STOP=10
# shellcheck disable=SC2034
USE_PROCD=1

# shellcheck disable=SC1091
. /lib/functions.sh

# Get the lan interface name
lan_device=
config_load network
config_get lan_device lan ifname

config_load dscp

_ipt() {
	iptables -w -t mangle "$@"
}

_add_dscp_rule() {
	_ipt -A dscp_prerouting -p "$proto" -s "$src_ip" -d "$dest_ip" "$@" -m comment --comment "$comment" -j DSCP --set-dscp-class "$class"
	_ipt -A dscp_prerouting -p "$proto" -s "$src_ip" -d "$dest_ip" "$@" -m comment --comment "$comment" -j RETURN
	_ipt -A dscp_postrouting -p "$proto" -s "$src_ip" -d "$dest_ip" "$@" -m comment --comment "$comment" -j DSCP --set-dscp-class "$class"
	_ipt -A dscp_postrouting -p "$proto" -s "$src_ip" -d "$dest_ip" "$@" -m comment --comment "$comment" -j RETURN
}

_add_dscp_domain() {
	domain=""; config_get domain "$1" name ""
	class=""; config_get class "$1" class ""
	[ -n "$domain" ] && uci -q add_list dhcp.@dnsmasq[0].ipset="/$domain/omr-$class"
}

_add_dscp_domains_rules() {
	for class in cs0 cs1 cs2 cs3 cs4 cs5 cs6 cs7 ef; do
		_ipt -A dscp_prerouting -m set --match-set omr-$class src,dst -m comment --comment "$class" -j DSCP --set-dscp-class "$class"
		_ipt -A dscp_prerouting -m set --match-set omr-$class src,dst -m comment --comment "$class" -j RETURN
		_ipt -A dscp_postrouting -m set --match-set omr-$class src,dst -m comment --comment "$class" -j DSCP --set-dscp-class "$class"
		_ipt -A dscp_postrouting -m set --match-set omr-$class src,dst -m comment --comment "$class" -j RETURN
	done
}

_add_dscp_rules() {
	proto=""     ; config_get proto "$1" proto all
	src_ip=""    ; config_get src_ip "$1" src_ip 0.0.0.0/0
	src_port=""  ; config_get src_port "$1" src_port 0:65535
	dest_ip=""   ; config_get dest_ip "$1" dest_ip 0.0.0.0/0
	dest_port="" ; config_get dest_port "$1" dest_port 0:65535
	class=""     ; config_get class "$1" class
	direction="" ; config_get direction "$1" direction "upload"
	comment=""   ; config_get comment "$1" comment "-"

	case "$direction" in
		upload|both)
			# Apply the rule locally
			case "$proto" in
				tcp|udp)
					_add_dscp_rule -m multiport --sports "$src_port" -m multiport --dports "$dest_port"
					;;
				*)
					_add_dscp_rule
					;;
			esac
			;;
		download|both)
			;;
	esac
}

_add_prerouting_chain() {
	_ipt -N "$1"
	_ipt -I PREROUTING -i "$lan_device" -j "$1"
}

_add_postrouting_chain() {
	_ipt -N "$1"
	_ipt -I POSTROUTING -j "$1"
}

_add_fwmark_chain() {
	_ipt -N dscp_mark
	_ipt -A PREROUTING -i "$lan_device" -j dscp_mark
	_ipt -A POSTROUTING -j dscp_mark
	for class in cs4 cs5 cs6 cs7; do
		# xtun (hex) -> 0x7874756e
		_ipt -A dscp_mark \
			-m comment --comment "$class" \
			-m dscp --dscp-class "$class" \
			-j MARK --set-mark 0x7874756e
	done
}

_add_dscp_output_chain() {
	_ipt -N dscp_output
	_ipt -I OUTPUT -j dscp_output
}

_remove_prerouting_chain() {
	_ipt -F "$1" 2>/dev/null || return
	_ipt -D PREROUTING -i "$lan_device" -j "$1"
	_ipt -X "$1"
}

_remove_postrouting_chain() {
	_ipt -F "$1" 2>/dev/null || return
	_ipt -D POSTROUTING -j "$1"
	_ipt -X "$1"
}

_remove_output_chain() {
	_ipt -F "$1" 2>/dev/null || return
	_ipt -D OUTPUT -j "$1"
	_ipt -X "$1"
}

_setup_tunnel() {
	# Mark the packets to route through xtun0
	_add_fwmark_chain
	# tun0: cs0 (default)
	# xtun0: cs6
	_ipt -A dscp_output -o "tun0" -j DSCP --set-dscp-class cs6
}

_cleanup() {
	_remove_prerouting_chain dscp_prerouting
	_remove_prerouting_chain dscp_mark
	_remove_postrouting_chain dscp_postrouting
	_remove_postrouting_chain dscp_mark
	_remove_output_chain dscp_output
}

start_service() {
	# Cleanup
	_cleanup

	# Add chains
	_add_prerouting_chain dscp_prerouting
	_add_postrouting_chain dscp_postrouting
	_add_dscp_output_chain
	_add_dscp_domains_rules

	# Setup the tunnels dscp / marks
	_setup_tunnel

	# Add rules base on the user configuration
	config_foreach _add_dscp_rules classify
	config_foreach _add_dscp_domain domains
}

stop_service() {
	_cleanup
}

reload_service() {
	start
}

service_triggers() {
	procd_add_reload_trigger dscp glorytun
}