# init script functions library for desktop linux systems

[ -n "$ZAPRET_BASE" ] || ZAPRET_BASE=/opt/zapret
# SHOULD EDIT config
. "$ZAPRET_BASE/config"

PIDDIR=/var/run

IPSET_CR="$ZAPRET_BASE/ipset/create_ipset.sh"

WS_USER=tpws

QNUM=200
NFQWS="$ZAPRET_BASE/nfq/nfqws"
NFQWS_OPT_BASE="--qnum=$QNUM --user=$WS_USER"

TPPORT=988
TPWS="$ZAPRET_BASE/tpws/tpws"
TPWS_LOCALHOST4=127.0.0.127
HOSTLIST="$ZAPRET_BASE/ipset/zapret-hosts.txt.gz"
[ -f "$HOSTLIST" ] || HOSTLIST="$ZAPRET_BASE/ipset/zapret-hosts.txt"
[ -f "$HOSTLIST" ] || HOSTLIST="$ZAPRET_BASE/ipset/zapret-hosts-user.txt"

TPWS_OPT_BASE="--user=$WS_USER --port=$TPPORT"
TPWS_OPT_BASE4="--bind-addr=$TPWS_LOCALHOST4"
TPWS_OPT_BASE6="--bind-addr=::1"
# first wait for lan to ifup, then wait for bind-wait-ip-linklocal seconds for link local address and bind-wait-ip for any ipv6 as the worst case
TPWS_OPT_BASE6_PRE="--bind-linklocal=prefer --bind-wait-ifup=30 --bind-wait-ip=30 --bind-wait-ip-linklocal=3"

[ -n "$IFACE_WAN" ] && IPT_OWAN="-o $IFACE_WAN"
[ -n "$IFACE_WAN" ] && IPT_IWAN="-i $IFACE_WAN"
[ -n "$IFACE_LAN" ] && IPT_ILAN="-i $IFACE_LAN"

[ -n "$DESYNC_MARK" ] || DESYNC_MARK=0x40000000

# max wait time for the link local ipv6 on the LAN interface
LINKLOCAL_WAIT_SEC=5

CUSTOM_SCRIPT="$ZAPRET_BASE/init.d/sysv/custom"
[ -f "$CUSTOM_SCRIPT" ] && . "$CUSTOM_SCRIPT"

IPSET_EXCLUDE="-m set ! --match-set nozapret"
IPSET_EXCLUDE6="-m set ! --match-set nozapret6"

exists()
{
	which "$1" >/dev/null 2>/dev/null
}
existf()
{
	type "$1" >/dev/null 2>/dev/null
}

on_off_function()
{
	# $1 : function name on
	# $2 : function name off
	# $3 : 0 - off, 1 - on
	local F="$1"
	[ "$3" = "1" ] || F="$2"
	shift
	shift
	shift
	"$F" "$@"
}


ipt()
{
	iptables -C "$@" 2>/dev/null || iptables -I "$@"
}
ipt_del()
{
	iptables -C "$@" 2>/dev/null && iptables -D "$@"
}
ipt_add_del()
{
	on_off_function ipt ipt_del "$@"
}
ipt6()
{
	ip6tables -C "$@" 2>/dev/null || ip6tables -I "$@"
}
ipt6_del()
{
	ip6tables -C "$@" 2>/dev/null && ip6tables -D "$@"
}
ipt6_add_del()
{
	on_off_function ipt6 ipt6_del "$@"
}

# there's no route_localnet for ipv6
# the best we can is to route to link local of the incoming interface
# OUTPUT - can DNAT to ::1
# PREROUTING - can't DNAT to ::1. can DNAT to link local of -i interface or to any global addr
# not a good idea to expose tpws to the world (bind to ::)

get_ipv6_linklocal()
{
	# $1 - interface name. if empty - any interface
	local dev
	[ -n "$1" ] && dev="dev $1"
	ip addr show $dev | sed -e 's/^.*inet6 \([^ ]*\)\/[0-9]* scope link.*$/\1/;t;d' | head -n 1
}
get_ipv6_global()
{
	# $1 - interface name. if empty - any interface
	local dev
	[ -n "$1" ] && dev="dev $1"
	ip addr show $dev | sed -e 's/^.*inet6 \([^ ]*\)\/[0-9]* scope global.*$/\1/;t;d' | head -n 1
}

iface_is_up()
{	
	# $1 - interface name
	[ -f /sys/class/net/$1/operstate ] || return
	local state
	read state </sys/class/net/$1/operstate
	[ "$state" != "down" ]
}
wait_ifup()
{
	# $1 - interface name
	local ct=0
	while
		iface_is_up $1 && return
		[ "$ct" -ge "$IFUP_WAIT_SEC" ] && break
		echo waiting for ifup of $1 for another $(($IFUP_WAIT_SEC - $ct)) seconds ...
		ct=$(($ct+1))
		sleep 1
	do :; done
	false
}


dnat6_target()
{
	# get target ip address for DNAT. prefer link locals
	# tpws should be as inaccessible from outside as possible
	# link local address can appear not immediately after ifup
	
	# DNAT6_TARGET=- means attempt was made but address was not found (to avoid multiple re-attempts)
	[ -n "$DNAT6_TARGET" ] || {
		local ct=0
		while
			DNAT6_TARGET=$(get_ipv6_linklocal $IFACE_LAN)
			[ -n "$DNAT6_TARGET" ] && break
			[ "$ct" -ge "$LINKLOCAL_WAIT_SEC" ] && break
			echo waiting for the link local for another $(($LINKLOCAL_WAIT_SEC - $ct)) seconds ...
			ct=$(($ct+1))
			sleep 1
		do :; done

		[ -n "$DNAT6_TARGET" ] || {
		    	echo no link local. getting global
			DNAT6_TARGET=$(get_ipv6_global $IFACE_LAN)
			[ -n "$DNAT6_TARGET" ] || {
				echo could not get any address
				DNAT6_TARGET=-
			}
		}
	}
}

prepare_tpws_fw4()
{
	# otherwise linux kernel will treat 127.0.0.0/8 as "martian" ip and refuse routing to it
	# NOTE : kernels <3.6 do not have this feature. consider upgrading or change DNAT to REDIRECT and do not bind to 127.0.0.0/8
	[ -n "$IFACE_LAN" ] && {
		iptables -C INPUT -i $IFACE_LAN -j input_lan_rule_zapret 2>/dev/null || {
			# allow localnet route only to special tpws IP
			iptables -N input_lan_rule_zapret 2>/dev/null
			iptables -F input_lan_rule_zapret
			iptables -A input_lan_rule_zapret -d $TPWS_LOCALHOST4 -j RETURN
			iptables -A input_lan_rule_zapret -d 127.0.0.0/8 -j DROP
			iptables -I INPUT -i $IFACE_LAN -j input_lan_rule_zapret
		}
		sysctl -qw net.ipv4.conf.$IFACE_LAN.route_localnet=1
	}
}
unprepare_tpws_fw4()
{
	[ -n "$IFACE_LAN" ] && {
		iptables -C INPUT -i $IFACE_LAN -j input_lan_rule_zapret 2>/dev/null && {
			sysctl -qw net.ipv4.conf.$IFACE_LAN.route_localnet=0
			iptables -D INPUT -i $IFACE_LAN -j input_lan_rule_zapret
			iptables -F input_lan_rule_zapret
			iptables -X input_lan_rule_zapret
		}
	}
}
unprepare_tpws_fw()
{
	unprepare_tpws_fw4
}


print_op()
{
	if [ "$1" = "1" ]; then
		echo "Adding ip$4tables rule for $3 : $2"
	else
		echo "Deleting ip$4tables rule for $3 : $2"
	fi
}

fw_tpws4()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv4
	# $3 - tpws port
	[ "$DISABLE_IPV4" = "1" ] || {
		[ "$1" = 1 ] && prepare_tpws_fw4
		print_op $1 "$2" "tpws"
		[ -n "$IFACE_LAN" ] && {
			ipt_add_del $1 PREROUTING -t nat $IPT_ILAN -p tcp $2 $IPSET_EXCLUDE dst -j DNAT --to $TPWS_LOCALHOST4:$3
	 	}
		ipt_add_del $1 OUTPUT -t nat $IPT_OWAN -m owner ! --uid-owner $WS_USER -p tcp $2 $IPSET_EXCLUDE dst -j DNAT --to $TPWS_LOCALHOST4:$3
	}
}
fw_tpws6()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv6
	# $3 - tpws port
	[ "$DISABLE_IPV6" = "1" ] || {
		print_op $1 "$2" "tpws" 6
		[ -n "$IFACE_LAN" ] && {
			dnat6_target
			[ "$DNAT6_TARGET" != "-" ] && ipt6_add_del $1 PREROUTING -t nat $IPT_ILAN -p tcp $2 $IPSET_EXCLUDE6 dst -j DNAT --to [$DNAT6_TARGET]:$3
	 	}
		ipt6_add_del $1 OUTPUT -t nat $IPT_OWAN -m owner ! --uid-owner $WS_USER -p tcp $2 $IPSET_EXCLUDE6 dst -j DNAT --to [::1]:$3
	}
}
fw_tpws()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv4
	# $3 - iptable filter for ipv6
	# $4 - tpws port
	fw_tpws4 $1 "$2" $4
	fw_tpws6 $1 "$3" $4
}


fw_nfqws_pre4()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv4
	# $3 - queue number
	[ "$DISABLE_IPV4" = "1" ] || {
		print_op $1 "$2" "nfqws prerouting"
		ipt_add_del $1 PREROUTING -t mangle $IPT_IWAN -p tcp $2 $IPSET_EXCLUDE src -j NFQUEUE --queue-num $3 --queue-bypass
	}
}
fw_nfqws_pre6()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv6
	# $3 - queue number
	[ "$DISABLE_IPV6" = "1" ] || {
		print_op $1 "$2" "nfqws prerouting" 6
		ipt6_add_del $1 PREROUTING -t mangle $IPT_IWAN -p tcp $2 $IPSET_EXCLUDE6 src -j NFQUEUE --queue-num $3 --queue-bypass
	}
}
fw_nfqws_pre()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv4
	# $3 - iptable filter for ipv6
	# $4 - queue number
	fw_nfqws_pre4 $1 "$2" $4
	fw_nfqws_pre6 $1 "$3" $4
}
fw_nfqws_post4()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv4
	# $3 - queue number
	[ "$DISABLE_IPV4" = "1" ] || {
		print_op $1 "$2" "nfqws postrouting"
		ipt_add_del $1 POSTROUTING -t mangle $IPT_OWAN -p tcp $2 $IPSET_EXCLUDE dst -j NFQUEUE --queue-num $3 --queue-bypass
	}
}
fw_nfqws_post6()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv6
	# $3 - queue number
	[ "$DISABLE_IPV6" = "1" ] || {
		print_op $1 "$2" "nfqws postrouting" 6
		ipt6_add_del $1 POSTROUTING -t mangle $IPT_OWAN -p tcp $2 $IPSET_EXCLUDE6 dst -j NFQUEUE --queue-num $3 --queue-bypass
	}
}
fw_nfqws_post()
{
	# $1 - 1 - add, 0 - del
	# $2 - iptable filter for ipv4
	# $3 - iptable filter for ipv6
	# $4 - queue number
	fw_nfqws_post4 $1 "$2" $4
	fw_nfqws_post6 $1 "$3" $4
}


run_daemon()
{
	# $1 - daemon number : 1,2,3,...
	# $2 - daemon
	# $3 - daemon args
	# use $PIDDIR/$DAEMONBASE$1.pid as pidfile

	local DAEMONBASE=$(basename $2)
	local PIDFILE=$PIDDIR/$DAEMONBASE$1.pid
	echo "Starting daemon $1: $2 $3"
	if exists start-stop-daemon ; then
		start-stop-daemon --start --pidfile "$PIDFILE" --background --make-pidfile --exec "$2" -- $3
	else
		if [ -f "$PIDFILE" ] && pgrep -F "$PIDFILE" "$DAEMONBASE" >/dev/null; then
			echo already running
		else
			"$2" $3 >/dev/null 2>/dev/null &
			PID=$!
			if [ -n "$PID" ]; then
				echo $PID >$PIDFILE
			else
				echo could not start daemon $1 : $2 $3
				false
			fi
		fi
	fi
}
stop_daemon()
{
	# $1 - daemon number : 1,2,3,...
	# $2 - daemon
	# use $PIDDIR/$DAEMONBASE$1.pid as pidfile
	local DAEMONBASE=$(basename $2)
	local PIDFILE=$PIDDIR/$DAEMONBASE$1.pid
	echo "Stopping daemon $1: $2"
	if exists start-stop-daemon ; then
		start-stop-daemon --stop --pidfile "$PIDFILE" --exec "$2"
	else
		if [ -f "$PIDFILE" ]; then
			read PID <"$PIDFILE"
			kill $PID
			rm -f "$PIDFILE"
		else
			echo no pidfile : $PIDFILE
		fi
	fi
}
do_daemon()
{
	# $1 - 1 - run, 0 - stop
	on_off_function run_daemon stop_daemon "$@"
}


prepare_user()
{
	# $WS_USER is required to prevent redirection of the traffic originating from TPWS itself
	# otherwise infinite loop will occur
	# also its good idea not to run tpws as root
	id -u $WS_USER >/dev/null 2>/dev/null || useradd --no-create-home --system --shell /bin/false $WS_USER
}
do_tpws()
{
	# $1 : 1 - run, 0 - stop
	# $2 : daemon number
	# $3 : daemon args

	[ "$1" = "1" ] && prepare_user

	[ "$DISABLE_IPV4" = "1" ] && [ "$DISABLE_IPV6" = "1" ] && return 0

	local OPT="$TPWS_OPT_BASE"

	[ "$DISABLE_IPV4" = "1" ] || OPT="$OPT $TPWS_OPT_BASE4"
	[ "$DISABLE_IPV6" = "1" ] || {
		OPT="$OPT $TPWS_OPT_BASE6"
		[ -n "$IFACE_LAN" ] && OPT="$OPT --bind-iface6=$IFACE_LAN $TPWS_OPT_BASE6_PRE"
	}

	do_daemon $1 $2 $TPWS "$OPT $3"
}
do_nfqws()
{
	# $1 : 1 - run, 0 - stop
	# $2 : daemon number
	# $3 : daemon args

	[ "$1" = "1" ] && prepare_user
	do_daemon $1 $2 $NFQWS "$NFQWS_OPT_BASE $3"
}


filter_apply_port_target()
{
	# $1 - var name of iptables filter
	local f
	if [ "$MODE_HTTP" = "1" ] && [ "$MODE_HTTPS" = "1" ]; then
		f="-m multiport --dports 80,443"
	elif [ "$MODE_HTTPS" = "1" ]; then
		f="--dport 443"
	elif [ "$MODE_HTTP" = "1" ]; then
		f="--dport 80"
	else
		echo WARNING !!! HTTP and HTTPS are both disabled
	fi
	eval $1="\"\$$1 $f\""
}
filter_apply_ipset_target()
{
	# $1 - var name of ipv4 iptables filter
	# $2 - var name of ipv6 iptables filter
	if [ "$MODE_FILTER" = "ipset" ]; then
		eval $1="\"\$$1 -m set --match-set zapret dst\""
		eval $2="\"\$$2 -m set --match-set zapret6 dst\""
	fi
}
filter_apply_hostlist_target()
{
	# $1 - var name of tpws or nfqws params
	[ "$MODE_FILTER" = "hostlist" ] && eval $1="\"\$$1 --hostlist=$HOSTLIST\""
}


create_ipset()
{
	echo "Creating ipset"
	"$IPSET_CR" "$@"
}



zapret_do_firewall()
{
	# $1 - 1 - add, 0 - del

	local first_packet_only="-m connbytes --connbytes-dir=original --connbytes-mode=packets --connbytes 2:4"
	local desync="-m mark ! --mark $DESYNC_MARK/$DESYNC_MARK"
	local f4 f6

	# always create ipsets. ip_exclude ipset is required
	[ "$1" != "1" ] || create_ipset no-update

	case "${MODE}" in
		tpws)
			if [ ! "$MODE_HTTP" = "1" ] && [ ! "$MODE_HTTPS" = "1" ]; then
				echo both http and https are disabled. not applying redirection.
			else
				filter_apply_port_target f4
				f6=$f4
				filter_apply_ipset_target f4 f6
				fw_tpws $1 "$f4" "$f6" $TPPORT
			fi
			;;
	
		nfqws)
			if [ ! "$MODE_HTTP" = "1" ] && [ ! "$MODE_HTTPS" = "1" ]; then
				echo both http and https are disabled. not applying redirection.
			else
				if [ "$MODE_HTTP_KEEPALIVE" = "1" ]; then
					if [ "$MODE_HTTP" = "1" ]; then
						f4="--dport 80"
						f6=$f4
						filter_apply_ipset_target f4 f6
						fw_nfqws_post $1 "$f4 $desync" "$f6 $desync" $QNUM
					fi
					if [ "$MODE_HTTPS" = "1" ]; then
						f4="--dport 443 $first_packet_only"
						f6=$f4
						filter_apply_ipset_target f4 f6
						fw_nfqws_post $1 "$f4 $desync" "$f6 $desync" $QNUM
					fi
				else
					filter_apply_port_target f4
					f4="$f4 $first_packet_only"
					f6=$f4
					filter_apply_ipset_target f4 f6
					fw_nfqws_post $1 "$f4 $desync" "$f6 $desync" $QNUM
				fi
			fi
			;;
		custom)
	    		existf zapret_custom_firewall && zapret_custom_firewall $1
			;;
	esac
	[ "$1" = 0 ] && unprepare_tpws_fw
}
zapret_apply_firewall()
{
	zapret_do_firewall 1 "$@"
}
zapret_unapply_firewall()
{
	zapret_do_firewall 0 "$@"
}

zapret_do_daemons()
{
	# $1 - 1 - run, 0 - stop

	local opt

	case "${MODE}" in
		tpws)
			opt="$TPWS_OPT"
			filter_apply_hostlist_target opt
			do_tpws $1 1 "$opt"
			;;
		nfqws)
			opt="$NFQWS_OPT_DESYNC"
			filter_apply_hostlist_target opt
			do_nfqws $1 1 "$opt"
			;;
		custom)
	    		existf zapret_custom_daemons && zapret_custom_daemons $1
			;;
	esac
}

zapret_run_daemons()
{
	zapret_do_daemons 1 "$@"
}
zapret_stop_daemons()
{
	zapret_do_daemons 0 "$@"
}