#!/bin/sh /etc/rc.common
# Copyright (C) 2018 Nick Peng (pymumu@gmail.com)

START=99
NAME=smartdns
SERVICE_USE_PID=1
SERVICE_WRITE_PID=1
SERVICE_DAEMONIZE=1
SERVICE_PID_FILE="/var/run/smartdns.pid"
BASECONFIGFILE="/etc/smartdns/smartdns.conf"
SMARTDNS_CONF="/var/etc/smartdns.conf"
ADDRESS_CONF="/etc/smartdns/address.conf"
CUSTOM_CONF="/etc/smartdns/custom.conf"
SMARTDNS_CONF_TMP="${SMARTDNS_CONF}.tmp"

set_forward_dnsmasq()
{
	local OLD_PORT="$1"
	addr="127.0.0.1#$OLD_PORT"
	OLD_SERVER="`uci get dhcp.@dnsmasq[0].server 2>/dev/null`"
	uci delete dhcp.@dnsmasq[0].server 2>/dev/null
	uci add_list dhcp.@dnsmasq[0].server=$addr
	for server in $OLD_SERVER; do
		uci add_list dhcp.@dnsmasq[0].server=$server
	done
	uci delete dhcp.@dnsmasq[0].resolvfile 2>/dev/null
	uci set dhcp.@dnsmasq[0].noresolv=1
	uci commit dhcp 
	/etc/init.d/dnsmasq restart
}

stop_forward_dnsmasq()
{
	local OLD_PORT="$1"
	addr="127.0.0.1#$OLD_PORT"
	uci del_list dhcp.@dnsmasq[0].server=$addr 2>/dev/null
	addrlist="`uci get dhcp.@dnsmasq[0].server 2>/dev/null`"
	if [ -z "$addrlist" ] ; then
		uci set dhcp.@dnsmasq[0].resolvfile=/tmp/resolv.conf.auto 2>/dev/null
		uci delete dhcp.@dnsmasq[0].noresolv 2>/dev/null
	fi
	uci commit dhcp
	/etc/init.d/dnsmasq restart
}

set_iptable()
{
	local ipv6_server=$1
	local tcp_server=$2

	IPS="`ifconfig | grep "inet addr" | grep -v ":127" | grep "Bcast" | awk '{print $2}' | awk -F : '{print $2}'`"
	for IP in $IPS
	do
		if [ "$tcp_server" == "1" ]; then
			iptables -t nat -A PREROUTING -p tcp -d $IP --dport 53 -j REDIRECT --to-ports $SMARTDNS_PORT >/dev/null 2>&1
		fi
		iptables -t nat -A PREROUTING -p udp -d $IP --dport 53 -j REDIRECT --to-ports $SMARTDNS_PORT >/dev/null 2>&1
	done

	if [ "$ipv6_server" == 0 ]; then
		return
	fi

	IPS="`ifconfig | grep "inet6 addr" | grep -v " fe80::" | grep -v " ::1" | grep "Global" | awk '{print $3}'`"
	for IP in $IPS
	do
		if [ "$tcp_server" == "1" ]; then
			ip6tables -t nat -A PREROUTING -p tcp -d $IP --dport 53 -j REDIRECT --to-ports $SMARTDNS_PORT >/dev/null 2>&1
		fi
		ip6tables -t nat -A PREROUTING -p udp -d $IP --dport 53 -j REDIRECT --to-ports $SMARTDNS_PORT >/dev/null 2>&1
	done

}

clear_iptable()
{
	local OLD_PORT="$1"
	local ipv6_server=$2
	IPS="`ifconfig | grep "inet addr" | grep -v ":127" | grep "Bcast" | awk '{print $2}' | awk -F : '{print $2}'`"
	for IP in $IPS
	do
		iptables -t nat -D PREROUTING -p udp -d $IP --dport 53 -j REDIRECT --to-ports $OLD_PORT >/dev/null 2>&1
		iptables -t nat -D PREROUTING -p tcp -d $IP --dport 53 -j REDIRECT --to-ports $OLD_PORT >/dev/null 2>&1
	done

	if [ "$ipv6_server" == 0 ]; then
		return
	fi

	IPS="`ifconfig | grep "inet6 addr" | grep -v " fe80::" | grep -v " ::1" | grep "Global" | awk '{print $3}'`"
	for IP in $IPS
	do
		ip6tables -t nat -D PREROUTING -p udp -d $IP --dport 53 -j REDIRECT --to-ports $OLD_PORT >/dev/null 2>&1
		ip6tables -t nat -D PREROUTING -p tcp -d $IP --dport 53 -j REDIRECT --to-ports $OLD_PORT >/dev/null 2>&1
	done
	
}

service_triggers() {
    procd_add_reload_trigger firewall
}


conf_append()
{
	echo "$1 $2" >> $SMARTDNS_CONF_TMP
}

load_server()
{
	local section="$1"
	config_get "port" "$section" "port" "53"
	config_get "type" "$section" "type" "udp"
	config_get "ip" "$section" "ip" ""

	if [ -z "$port" ] || [ -z "$ip" ] || [ -z "$type" ]; then
		return
	fi

	SERVER="server"
	if [ "$type" = "tcp" ]; then
		SERVER="server-tcp"
	elif [ "$type" = "tls" ]; then
		SERVER="server-tls"
	fi

	if [ ! -z "`echo $ip | grep ":"`" ]; then
		if [ -z "`echo $ip | grep "\["`" ]; then
			ip="[$ip]"
		fi
	fi

	conf_append "$SERVER" "$ip:$port"

}

start_service() {
	local section="$1"
	args=""

	config_get "server_name" "$section" "server_name" ""
	if [ ! -z "$server_name" ]; then
		conf_append "server-name" "$server_name"	
	fi

	config_get "port" "$section" "port" "6053"
	config_get "ipv6_server" "$section" "ipv6_server" "1"
	config_get "tcp_server" "$section" "tcp_server" "1"
	if [ "$ipv6_server" = "1" ]; then
		conf_append "bind" "[::]:$port"
	else
		conf_append "bind" ":$port"
	fi

	if [ "$tcp_server" = "1" ]; then
		if [ "$ipv6_server" = "1" ]; then
			conf_append "bind-tcp" "[::]:$port"
		else
			conf_append "bind-tcp" ":$port"
		fi
	fi
	SMARTDNS_PORT="$port"

	mkdir -p $(dirname $SMARTDNS_CONF)

	config_get "cache_size" "$section" "cache_size" ""
	if [ ! -z "$cache_size" ]; then
		conf_append "cache-size" "$cache_size"
	fi

	config_get "rr_ttl" "$section" "rr_ttl" ""
	if [ ! -z "$rr_ttl" ]; then
		conf_append "rr-ttl" "$rr_ttl"
	fi

	config_get "rr_ttl_min" "$section" "rr_ttl_min" ""
	if [ ! -z "$rr_ttl_min" ]; then
		conf_append "rr-ttl-min" "$rr_ttl_min"
	fi

	config_get "rr_ttl_max" "$section" "rr_ttl_max" ""
	if [ ! -z "$rr_ttl_max" ]; then
		conf_append "rr-ttl-max" "$rr_ttl_max"
	fi

	config_get "log_size" "$section" "log_size" "128K"
	if [ ! -z "$log_size" ]; then
		conf_append "log-size" "$log_size"
	fi

	config_get "log_num" "$section" "log_num" "3"
	if [ ! -z "$log_num" ]; then
		conf_append "log-num" "$log_num"
	fi

	config_get "log_level" "$section" "log_level" "error"
	if [ ! -z "$log_level" ]; then
		conf_append "log-level" "$log_level"
	fi

	config_get "log_file" "$section" "log_file" ""
	if [ ! -z "$log_file" ]; then
		conf_append "log-file" "$log_file"
	fi

	config_get "redirect" "$section" "redirect" "none"
	config_get "old_redirect" "$section" "old_redirect" "none"
	config_get "old_port" "$section" "old_port" "0"

	if [ "$old_redirect" != "none" ] && [ "$old_port" != "0" ]; then
		clear_iptable "$old_port" "$ipv6_server"
		stop_forward_dnsmasq "$old_port"
	fi

	if [ "$redirect" = "redirect" ]; then
		set_iptable $ipv6_server $tcp_server
	elif [ "$redirect" = "dnsmasq-upstream" ]; then
		set_forward_dnsmasq "$SMARTDNS_PORT"
	fi

	uci delete smartdns.@smartdns[0].old_redirect 2>/dev/null
	uci delete smartdns.@smartdns[0].old_port 2>/dev/null
	uci add_list smartdns.@smartdns[0].old_redirect="$redirect" 2>/dev/null
	uci add_list smartdns.@smartdns[0].old_port="$SMARTDNS_PORT" 2>/dev/null

	config_foreach load_server "server"

	echo "conf-file $ADDRESS_CONF" >> $SMARTDNS_CONF_TMP
	echo "conf-file $CUSTOM_CONF" >> $SMARTDNS_CONF_TMP

	config_get_bool "enabled" "$section" "enabled" '0'
	mv $SMARTDNS_CONF_TMP $SMARTDNS_CONF
	[ "$enabled" -gt 0 ] || return 1
	service_start /usr/sbin/smartdns $args -c $SMARTDNS_CONF
}

start() {
	config_load "smartdns"
	config_foreach start_service "smartdns"
}

stop() {
	service_stop /usr/sbin/smartdns
}

