shadowsocks-libev: rewrite ss-rules

 - New UCI options ifnames, dst_default
 - UCI options src_ips_xxx now accept cidr as their values
 - Export ipset names as part of the interface so that it can be
   depended on and used by other programs
 - Bypass only remote servers used ss-redir instances, so that it's
   possible to let other servers to go through existing re-redir
   instances

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

4 files changed, 253 insertions, 274 deletions

diff --git a/net/shadowsocks-libev/Makefile b/net/shadowsocks-libev/Makefile
index 2bca7f44b..307fac9d8 100644
--- a/net/shadowsocks-libev/Makefile
+++ b/net/shadowsocks-libev/Makefile
@@ -14,7 +14,7 @@ include $(TOPDIR)/rules.mk
 #
 PKG_NAME:=shadowsocks-libev
 PKG_VERSION:=3.0.8
-PKG_RELEASE:=6
+PKG_RELEASE:=7
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://github.com/shadowsocks/shadowsocks-libev/releases/download/v$(PKG_VERSION)
diff --git a/net/shadowsocks-libev/README.md b/net/shadowsocks-libev/README.md
index 75790ea69..bb0545c51 100644
--- a/net/shadowsocks-libev/README.md
+++ b/net/shadowsocks-libev/README.md
@@ -39,8 +39,9 @@ We can have multiple instances of component and `server` sections.  The relation
 
 	redir_tcp		name of ss_redir section with mode tcp_only or tcp_and_udp
 	redir_udp		name of ss_redir section with mode udp_only or tcp_and_udp
+	ifnames			only apply rules on packets from these ifnames
 
-	--- incoming packets having source address in
+	--- for incoming packets having source address in
 
 	src_ips_bypass		will bypass the redir chain
 	src_ips_forward		will always go through the redir chain
@@ -50,10 +51,6 @@ We can have multiple instances of component and `server` sections.  The relation
 
 	src_default		bypass, forward, [checkdst]
 
-	--- for local out tcp packets, the default action can be specified with
-
-	local_default		[bypass], forward, checkdst
-
 	--- if the previous check result is checkdst,
 	--- then packets having destination address in
 
@@ -62,6 +59,18 @@ We can have multiple instances of component and `server` sections.  The relation
 	dst_ips_forward_file
 	dst_ips_forward		will go through the redir chain
 
+	--- otherwise, the default action can be specified with
+
+	dst_default		[bypass], forward
+
+	--- for local out tcp packets, the default action can be specified with
+
+	local_default		[bypass], forward, checkdst
+
+ss-rules uses kernel ipset mechanism for storing addresses/networks.  Those ipsets are also part of the API and can be populated by other programs, e.g. dnsmasq with builtin ipset support.  For more details please read output of `ss-rules --help`
+
+Note also that `src_ips_xx` and `dst_ips_xx` actually also accepts cidr network representation.  Names are retained for backward compatibility coniderations
+
 ## notes and faq
 
 Useful paths and commands for debugging
diff --git a/net/shadowsocks-libev/files/shadowsocks-libev.init b/net/shadowsocks-libev/files/shadowsocks-libev.init
index e198c7e3b..0142cc1d8 100644
--- a/net/shadowsocks-libev/files/shadowsocks-libev.init
+++ b/net/shadowsocks-libev/files/shadowsocks-libev.init
@@ -107,7 +107,7 @@ ss_xxx() {
 
 	[ -x "$bin" ] || return
 	eval "$("validate_${cfgtype}_section" "$cfg" ss_validate_mklocal)"
-	"validate_${cfgtype}_section" "$cfg"
+	"validate_${cfgtype}_section" "$cfg" || return 1
 	[ "$disabled" = 0 ] || return
 
 	if ss_mkjson \
@@ -127,21 +127,17 @@ ss_xxx() {
 }
 
 ss_rules_cb() {
-	local cfgserver
-	local server
-
-	[ "$cfgtype" != ss_server ] || return
-	config_get cfgserver "$cfg" server
-	config_get server "$cfgserver" server
+	local cfgserver server
 
-	ss_rules_servers="$ss_rules_servers $server"
 	if [ "$cfgtype" = ss_redir ]; then
+		config_get cfgserver "$cfg" server
+		config_get server "$cfgserver" server
+		ss_redir_servers="$ss_redir_servers $server"
 		if [ "$mode" = tcp_only -o "$mode" = "tcp_and_udp" ]; then
 			eval "ss_rules_redir_tcp_$cfg=$local_port"
 		fi
 		if [ "$mode" = udp_only -o "$mode" = "tcp_and_udp" ]; then
 			eval "ss_rules_redir_udp_$cfg=$local_port"
-			eval "ss_rules_redir_server_udp_$cfg=$server"
 		fi
 	fi
 }
@@ -150,48 +146,37 @@ ss_rules() {
 	local cfg="ss_rules"
 	local bin="$ss_bindir/ss-rules"
 	local cfgtype
-	local args local_port_tcp local_port_udp server_udp
-	local i a_args d_args
+	local local_port_tcp local_port_udp
 
 	[ -x "$bin" ] || return 1
 	config_get cfgtype "$cfg" TYPE
 	[ "$cfgtype" = ss_rules ] || return 1
 
 	eval "$(validate_ss_rules_section "$cfg" ss_validate_mklocal)"
-	validate_ss_rules_section "$cfg"
+	validate_ss_rules_section "$cfg" || return 1
 	[ "$disabled" = 0 ] || return 1
 
 	eval local_port_tcp="\$ss_rules_redir_tcp_$redir_tcp"
 	eval local_port_udp="\$ss_rules_redir_udp_$redir_udp"
-	eval server_udp="\$ss_rules_redir_server_udp_$redir_udp"
-	[ -z "$local_port_udp" ] || args="$args -U"
-	case "$local_default" in
-		forward) args="$args -O" ;;
-		checkdst) args="$args -o" ;;
-	esac
-	case "$src_default" in
-		bypass) d_args=RETURN ;;
-		forward) d_args=SS_SPEC_WAN_FW ;;
-		checkdst) d_args=SS_SPEC_WAN_AC ;;
-	esac
-	ss_rules_servers="$(echo "$ss_rules_servers" | tr ' ' '\n' | sort -u)"
-	for i in $src_ips_bypass; do a_args="b,$i $a_args"; done
-	for i in $src_ips_forward; do a_args="g,$i $a_args"; done
-	for i in $src_ips_checkdst; do a_args="n,$i $a_args"; done
+	[ -n "$local_port_tcp" -o -n "$local_port_udp" ] || return 1
+	ss_redir_servers="$(echo "$ss_redir_servers" | tr ' ' '\n' | sort -u)"
 
 	"$bin" \
-			-s "$ss_rules_servers" \
+			-s "$ss_redir_servers" \
 			-l "$local_port_tcp" \
-			-S "$server_udp" \
 			-L "$local_port_udp" \
-			-B "$dst_ips_bypass_file" \
-			-W "$dst_ips_forward_file" \
-			-b "$dst_ips_bypass" \
-			-w "$dst_ips_forward" \
-			-e "$ipt_args" \
-			-a "$a_args" \
-			-d "$d_args" \
-			$args \
+			--src-default "$src_default" \
+			--dst-default "$dst_default" \
+			--local-default "$local_default" \
+			--dst-bypass-file "$dst_ips_bypass_file" \
+			--dst-forward-file "$dst_ips_forward_file" \
+			--dst-bypass "$dst_ips_bypass" \
+			--dst-forward "$dst_ips_forward" \
+			--src-bypass "$src_ips_bypass" \
+			--src-forward "$src_ips_forward" \
+			--src-checkdst "$src_ips_checkdst" \
+			--ifnames "$ifnames" \
+			--ipt-extra "$ipt_args" \
 		|| "$bin" -f
 }
 
@@ -299,15 +284,17 @@ validate_ss_rules_section() {
 		'disabled:bool:0' \
 		'redir_tcp:uci("shadowsocks-libev", "@ss_redir")' \
 		'redir_udp:uci("shadowsocks-libev", "@ss_redir")' \
-		'src_ips_bypass:list(ipaddr)' \
-		'src_ips_forward:list(ipaddr)' \
-		'src_ips_checkdst:list(ipaddr)' \
+		'src_ips_bypass:list(or(ip4addr,cidr4))' \
+		'src_ips_forward:list(or(ip4addr,cidr4))' \
+		'src_ips_checkdst:list(or(ip4addr,cidr4))' \
 		'dst_ips_bypass_file:file' \
-		'dst_ips_bypass:list(ipaddr)' \
+		'dst_ips_bypass:list(or(ip4addr,cidr4))' \
 		'dst_ips_forward_file:file' \
-		'dst_ips_forward:list(ipaddr)' \
-		'src_default:or("bypass", "forward", "checkdst")' \
-		'local_default:or("bypass", "forward", "checkdst")' \
+		'dst_ips_forward:list(or(ip4addr,cidr4))' \
+		'src_default:or("bypass", "forward", "checkdst"):checkdst' \
+		'dst_default:or("bypass", "forward"):bypass' \
+		'local_default:or("bypass", "forward", "checkdst"):bypass' \
+		'ifnames:list(maxlength(15))' \
 		'ipt_args:string'
 }
 
diff --git a/net/shadowsocks-libev/files/ss-rules b/net/shadowsocks-libev/files/ss-rules
index 8bd7264af..660360434 100755
--- a/net/shadowsocks-libev/files/ss-rules
+++ b/net/shadowsocks-libev/files/ss-rules
@@ -1,260 +1,243 @@
-#!/bin/sh
+#!/bin/sh -e
 #
-# Copyright (C) 2014-2017 Jian Chang <aa65535@live.com>
+# Copyright (C) 2017 Yousong Zhou <yszhou4tech@gmail.com>
+#
+# The design idea was derived from ss-rules by Jian Chang <aa65535@live.com>
 #
 # This is free software, licensed under the GNU General Public License v3.
 # See /LICENSE for more information.
 #
 
-usage() {
-	cat <<-EOF
-		Usage: ss-rules [options]
-
-		Valid options are:
-
-		    -s <server_ips>         ip address of shadowsocks remote server
-		    -l <local_port>         port number of shadowsocks local server
-		    -S <server_ips>         ip address of shadowsocks remote UDP server
-		    -L <local_port>         port number of shadowsocks local UDP server
-		    -B <ip_list_file>       a file whose content is bypassed ip list
-		    -b <wan_ips>            wan ip of will be bypassed
-		    -W <ip_list_file>       a file whose content is forwarded ip list
-		    -w <wan_ips>            wan ip of will be forwarded
-		    -I <interface>          proxy only for the given interface
-		    -d <target>             the default target of lan access control
-		    -a <lan_hosts>          lan ip of access control, need a prefix to
-		                            define proxy type
-		    -e <extra_args>         extra arguments for iptables
-		    -o                      apply the rules to the OUTPUT chain
-		    -O                      apply the global rules to the OUTPUT chain
-		    -u                      enable udprelay mode, TPROXY is required
-		    -U                      enable udprelay mode, using different IP
-		                            and ports for TCP and UDP
-		    -f                      flush the rules
-		    -h                      show this help message and exit
+ss_usage() {
+	cat >&2 <<EOF
+Usage: ss-rules [options]
+
+	-h, --help      Show this help message then exit
+	-f, --flush     Flush rules, ipset then exit
+	-l <port>       Local port number of ss-redir with TCP mode
+	-L <port>       Local port number of ss-redir with UDP mode
+	-s <ips>        List of ip addresses of remote shadowsocks server
+	--ifnames       Only apply rules on packets from these ifnames
+	--src-bypass <ips|cidr>
+	--src-forward <ips|cidr>
+	--src-checkdst <ips|cidr>
+	--src-default <bypass|forward|checkdst>
+	                Packets will have their src ip checked in order against
+	                bypass, forward, checkdst list and will bypass, forward
+	                through, or continue to have their dst ip checked
+	                respectively on the first match.  Otherwise, --src-default
+	                decide the default action
+	--dst-bypass <ips|cidr>
+	--dst-forward <ips|cidr>
+	--dst-bypass-file <file>
+	--dst-forward-file <file>
+	--dst-default <bypass|forward>
+	                Same as with their --src-xx equivalent
+	--local-default <bypass|forward|checkdst>
+	                Default action for local out TCP traffic
+
+The following ipsets will be created by ss-rules.  They are also intended to be
+populated by other programs like dnsmasq with ipset support
+
+	ss_rules_src_bypass
+	ss_rules_src_forward
+	ss_rules_src_checkdst
+	ss_rules_dst_bypass
+	ss_rules_dst_forward
 EOF
-	exit $1
 }
 
-loger() {
-	# 1.alert 2.crit 3.err 4.warn 5.notice 6.info 7.debug
-	logger -st ss-rules[$$] -p$1 $2
+o_dst_bypass_="
+	0.0.0.0/8
+	10.0.0.0/8
+	100.64.0.0/10
+	127.0.0.0/8
+	169.254.0.0/16
+	172.16.0.0/12
+	192.0.0.0/24
+	192.0.2.0/24
+	192.31.196.0/24
+	192.52.193.0/24
+	192.88.99.0/24
+	192.168.0.0/16
+	192.175.48.0/24
+	198.18.0.0/15
+	198.51.100.0/24
+	203.0.113.0/24
+	224.0.0.0/4
+	240.0.0.0/4
+	255.255.255.255
+"
+o_src_default=bypass
+o_dst_default=bypass
+o_local_default=bypass
+
+__errmsg() {
+	echo "ss-rules: $*" >&2
 }
 
-flush_rules() {
-	iptables-save -c | grep -v "SS_SPEC" | iptables-restore -c
-	if command -v ip >/dev/null 2>&1; then
-		ip rule del fwmark 1 lookup 100 2>/dev/null
-		ip route del local default dev lo table 100 2>/dev/null
-	fi
-	for setname in $(ipset -n list | grep "ss_spec"); do
-		ipset destroy $setname 2>/dev/null
+ss_rules_parse_args() {
+	while [ "$#" -gt 0 ]; do
+		case "$1" in
+			-h|--help) ss_usage; exit 0;;
+			-f|--flush) ss_rules_flush; exit 0;;
+			-l) o_redir_tcp_port="$2"; shift 2;;
+			-L) o_redir_udp_port="$2"; shift 2;;
+			-s) o_remote_servers="$2"; shift 2;;
+			--ifnames) o_ifnames="$2"; shift 2;;
+			--ipt-extra) o_ipt_extra="$2"; shift 2;;
+			--src-default) o_src_default="$2"; shift 2;;
+			--dst-default) o_dst_default="$2"; shift 2;;
+			--local-default) o_local_default="$2"; shift 2;;
+			--src-bypass) o_src_bypass="$2"; shift 2;;
+			--src-forward) o_src_forward="$2"; shift 2;;
+			--src-checkdst) o_src_checkdst="$2"; shift 2;;
+			--dst-bypass) o_dst_bypass="$2"; shift 2;;
+			--dst-forward) o_dst_forward="$2"; shift 2;;
+			--dst-bypass-file) o_dst_bypass_file="$2"; shift 2;;
+			--dst-forward-file) o_dst_forward_file="$2"; shift 2;;
+			*) __errmsg "unknown option $1"; return 1;;
+		esac
 	done
-	FWI=$(uci get firewall.shadowsocks.path 2>/dev/null)
-	[ -n "$FWI" ] && echo '# firewall include file' >$FWI
-	return 0
-}
 
-ipset_init() {
-	ipset -! restore <<-EOF || return 1
-		create ss_spec_src_ac hash:ip hashsize 64
-		create ss_spec_src_bp hash:ip hashsize 64
-		create ss_spec_src_fw hash:ip hashsize 64
-		create ss_spec_dst_sp hash:net hashsize 64
-		create ss_spec_dst_bp hash:net hashsize 64
-		create ss_spec_dst_fw hash:net hashsize 64
-		$(gen_lan_host_ipset_entry)
-		$(gen_special_purpose_ip | sed -e "s/^/add ss_spec_dst_sp /")
-		$(sed -e "s/^/add ss_spec_dst_bp /" ${WAN_BP_LIST:=/dev/null} 2>/dev/null)
-		$(for ip in $WAN_BP_IP; do echo "add ss_spec_dst_bp $ip"; done)
-		$(sed -e "s/^/add ss_spec_dst_fw /" ${WAN_FW_LIST:=/dev/null} 2>/dev/null)
-		$(for ip in $WAN_FW_IP; do echo "add ss_spec_dst_fw $ip"; done)
-EOF
-	return 0
-}
-
-ipt_nat() {
-	include_ac_rules nat
-	ipt="iptables -t nat"
-	$ipt -A SS_SPEC_WAN_FW -p tcp \
-		-j REDIRECT --to-ports $local_port || return 1
-	if [ -n "$OUTPUT" ]; then
-		$ipt -N SS_SPEC_WAN_DG
-		$ipt -A SS_SPEC_WAN_DG -m set --match-set ss_spec_dst_sp dst -j RETURN
-		$ipt -A SS_SPEC_WAN_DG -p tcp $EXT_ARGS -j $OUTPUT
-		$ipt -I OUTPUT 1 -p tcp -j SS_SPEC_WAN_DG
+	if [ -z "$o_redir_tcp_port" -a -z "$o_redir_udp_port" ]; then
+		__errmsg "Requires at least -l or -L option"
+		return 1
 	fi
-	return $?
 }
 
-ipt_mangle() {
-	[ -n "$TPROXY" ] || return 0
-	if !(lsmod | grep -q TPROXY && command -v ip >/dev/null); then
-		loger 4 "TPROXY or ip not found."
-		return 0
-	fi
-	ip rule add fwmark 1 lookup 100
-	ip route add local default dev lo table 100
-	include_ac_rules mangle
-	iptables -t mangle -A SS_SPEC_WAN_FW -p udp \
-		-j TPROXY --on-port $LOCAL_PORT --tproxy-mark 0x01/0x01
-	return $?
+ss_rules_flush() {
+	local setname
+
+	iptables-save --counters | grep -v ss_rules_ | iptables-restore --counters
+	while ip rule del fwmark 1 lookup 100 2>/dev/null; do true; done
+	ip route flush table 100
+	for setname in $(ipset -n list | grep "ss_rules_"); do
+		ipset destroy "$setname" 2>/dev/null || true
+	done
 }
 
-export_ipt_rules() {
-	[ -n "$FWI" ] || return 0
-	cat <<-CAT >>$FWI
-	iptables-save -c | grep -v "SS_SPEC" | iptables-restore -c
-	iptables-restore -n <<-EOF
-	$(iptables-save | grep -E "SS_SPEC|^\*|^COMMIT" |\
-			sed -e "s/^-A \(OUTPUT\|PREROUTING\)/-I \1 1/")
+ss_rules_ipset_init() {
+	ipset --exist restore <<-EOF
+		create ss_rules_src_bypass hash:net hashsize 64
+		create ss_rules_src_forward hash:net hashsize 64
+		create ss_rules_src_checkdst hash:net hashsize 64
+		create ss_rules_dst_bypass hash:net hashsize 64
+		create ss_rules_dst_bypass_ hash:net hashsize 64
+		create ss_rules_dst_forward hash:net hashsize 64
+		$(ss_rules_ipset_mkadd ss_rules_dst_bypass_ "$o_dst_bypass_ $o_remote_servers")
+		$(ss_rules_ipset_mkadd ss_rules_src_bypass "$o_src_bypass")
+		$(ss_rules_ipset_mkadd ss_rules_src_forward "$o_src_forward")
+		$(ss_rules_ipset_mkadd ss_rules_src_checkdst "$o_src_checkdst")
+		$(ss_rules_ipset_mkadd ss_rules_dst_bypass "$o_dst_bypass $(cat "$o_dst_bypass_file" 2>/dev/null)")
+		$(ss_rules_ipset_mkadd ss_rules_dst_forward "$o_dst_forward $(cat "$o_dst_forward_file" 2>/dev/null)")
 	EOF
-CAT
-	return $?
 }
 
-gen_lan_host_ipset_entry() {
-	for host in $LAN_HOSTS; do
-		case "${host:0:1}" in
-			n|N)
-				echo add ss_spec_src_ac ${host:2}
-				;;
-			b|B)
-				echo add ss_spec_src_bp ${host:2}
-				;;
-			g|G)
-				echo add ss_spec_src_fw ${host:2}
-				;;
-		esac
+ss_rules_ipset_mkadd() {
+	local setname="$1"; shift
+	local i
+
+	for i in $*; do
+		echo "add $setname $i"
 	done
 }
 
-gen_special_purpose_ip() {
-	cat <<-EOF | grep -E "^([0-9]{1,3}\.){3}[0-9]{1,3}"
-		0.0.0.0/8
-		10.0.0.0/8
-		100.64.0.0/10
-		127.0.0.0/8
-		169.254.0.0/16
-		172.16.0.0/12
-		192.0.0.0/24
-		192.0.2.0/24
-		192.31.196.0/24
-		192.52.193.0/24
-		192.88.99.0/24
-		192.168.0.0/16
-		192.175.48.0/24
-		198.18.0.0/15
-		198.51.100.0/24
-		203.0.113.0/24
-		224.0.0.0/4
-		240.0.0.0/4
-		255.255.255.255
-		$server
-		$SERVER
-EOF
+ss_rules_iptchains_init() {
+	ss_rules_iptchains_init_tcp
+	ss_rules_iptchains_init_udp
 }
 
-include_ac_rules() {
-	local protocol=$([ "$1" = "mangle" ] && echo udp || echo tcp)
-	iptables-restore -n <<-EOF
-	*$1
-	:SS_SPEC_LAN_DG - [0:0]
-	:SS_SPEC_LAN_AC - [0:0]
-	:SS_SPEC_WAN_AC - [0:0]
-	:SS_SPEC_WAN_FW - [0:0]
-	-A SS_SPEC_LAN_DG -m set --match-set ss_spec_dst_sp dst -j RETURN
-	-A SS_SPEC_LAN_DG -p $protocol $EXT_ARGS -j SS_SPEC_LAN_AC
-	-A SS_SPEC_LAN_AC -m set --match-set ss_spec_src_bp src -j RETURN
-	-A SS_SPEC_LAN_AC -m set --match-set ss_spec_src_fw src -j SS_SPEC_WAN_FW
-	-A SS_SPEC_LAN_AC -m set --match-set ss_spec_src_ac src -j SS_SPEC_WAN_AC
-	-A SS_SPEC_LAN_AC -j ${LAN_TARGET:=SS_SPEC_WAN_AC}
-	-A SS_SPEC_WAN_AC -m set --match-set ss_spec_dst_fw dst -j SS_SPEC_WAN_FW
-	-A SS_SPEC_WAN_AC -m set --match-set ss_spec_dst_bp dst -j RETURN
-	-A SS_SPEC_WAN_AC -j SS_SPEC_WAN_FW
-	$(gen_prerouting_rules $protocol)
-	COMMIT
-EOF
+ss_rules_iptchains_init_tcp() {
+	local ipt="iptables -t nat"
+	local local_target
+	local forward_rules
+	local r
+
+	[ -n "$o_redir_tcp_port" ] || return 0
+
+	ss_rules_iptchains_init_ nat tcp
+
+	case "$o_local_default" in
+		checkdst) local_target=ss_rules_dst ;;
+		forward) local_target=ss_rules_forward ;;
+		bypass|*) return 0;;
+	esac
+
+	iptables-restore --noflush <<-EOF
+		*nat
+		:ss_rules_local_out -
+		-I OUTPUT 1 -p tcp -j ss_rules_local_out
+		-A ss_rules_local_out -m set --match-set ss_rules_dst_bypass_ dst -j RETURN
+		-A ss_rules_local_out -p tcp $o_ipt_extra -j $local_target -m comment --comment "local_default: $o_local_default"
+		COMMIT
+	EOF
 }
 
-gen_prerouting_rules() {
-	[ -z "$IFNAMES" ] && echo -I PREROUTING 1 -p $1 -j SS_SPEC_LAN_DG
-	for ifname in $IFNAMES; do
-		echo -I PREROUTING 1 -i $ifname -p $1 -j SS_SPEC_LAN_DG
-	done
+ss_rules_iptchains_init_udp() {
+	[ -n "$o_redir_udp_port" ] || return 0
+	ss_rules_iptchains_init_ mangle udp
 }
 
-while getopts ":s:l:S:L:B:b:W:w:I:d:a:e:oOuUfh" arg; do
-	case "$arg" in
-		s)
-			server=$(for ip in $OPTARG; do echo $ip; done)
-			;;
-		l)
-			local_port=$OPTARG
-			;;
-		S)
-			SERVER=$(for ip in $OPTARG; do echo $ip; done)
-			;;
-		L)
-			LOCAL_PORT=$OPTARG
-			;;
-		B)
-			WAN_BP_LIST=$OPTARG
-			;;
-		b)
-			WAN_BP_IP=$OPTARG
-			;;
-		W)
-			WAN_FW_LIST=$OPTARG
-			;;
-		w)
-			WAN_FW_IP=$OPTARG
-			;;
-		I)
-			IFNAMES=$OPTARG
-			;;
-		d)
-			LAN_TARGET=$OPTARG
-			;;
-		a)
-			LAN_HOSTS=$OPTARG
-			;;
-		e)
-			EXT_ARGS=$OPTARG
-			;;
-		o)
-			OUTPUT=SS_SPEC_WAN_AC
-			;;
-		O)
-			OUTPUT=SS_SPEC_WAN_FW
-			;;
-		u)
-			TPROXY=1
-			;;
-		U)
-			TPROXY=2
-			;;
-		f)
-			flush_rules
-			exit 0
+ss_rules_iptchains_init_() {
+	local table="$1"
+	local proto="$2"
+	local forward_rules
+	local src_default_target dst_default_target
+
+	case "$proto" in
+		tcp)
+			forward_rules="-A ss_rules_forward -p tcp -j REDIRECT --to-ports $o_redir_tcp_port"
 			;;
-		h)
-			usage 0
+		udp)
+			ip rule add fwmark 1 lookup 100
+			ip route add local default dev lo table 100
+			forward_rules="-A ss_rules_forward -p udp -j TPROXY --on-port "$o_redir_udp_port" --tproxy-mark 0x01/0x01"
 			;;
 	esac
-done
+	case "$o_src_default" in
+		forward) src_default_target=ss_rules_forward ;;
+		checkdst) src_default_target=ss_rules_dst ;;
+		bypass|*) src_default_target=RETURN ;;
+	esac
+	case "$o_dst_default" in
+		forward) dst_default_target=ss_rules_forward ;;
+		bypass|*) dst_default_target=RETURN ;;
+	esac
+	iptables-restore --noflush <<-EOF
+		*$table
+		:ss_rules_pre_src -
+		:ss_rules_src -
+		:ss_rules_dst -
+		:ss_rules_forward -
+		$(ss_rules_iptchains_mkprerules "$proto")
+		-A ss_rules_pre_src -m set --match-set ss_rules_dst_bypass_ dst -j RETURN
+		-A ss_rules_pre_src -p $proto $o_ipt_extra -j ss_rules_src
+		-A ss_rules_src -m set --match-set ss_rules_src_bypass src -j RETURN
+		-A ss_rules_src -m set --match-set ss_rules_src_forward src -j ss_rules_forward
+		-A ss_rules_src -m set --match-set ss_rules_src_checkdst src -j ss_rules_dst
+		-A ss_rules_src -j $src_default_target -m comment --comment "src_default: $o_src_default"
+		-A ss_rules_dst -m set --match-set ss_rules_dst_bypass dst -j RETURN
+		-A ss_rules_dst -m set --match-set ss_rules_dst_forward dst -j ss_rules_forward
+		-A ss_rules_dst -j $dst_default_target -m comment --comment "dst_default: $o_dst_default"
+		$forward_rules
+		COMMIT
+	EOF
+}
 
-[ -z "$server" -o -z "$local_port" ] && usage 2
+ss_rules_iptchains_mkprerules() {
+	local proto="$1"
 
-if [ "$TPROXY" = 1 ]; then
-	unset SERVER
-	LOCAL_PORT=$local_port
-elif [ "$TPROXY" = 2 ]; then
-	: ${SERVER:?"You must assign an ip for the udp relay server."}
-	: ${LOCAL_PORT:?"You must assign a port for the udp relay server."}
-fi
+	if [ -z "$o_ifnames" ]; then
+		echo "-I PREROUTING 1 -p $proto -j ss_rules_pre_src"
+	else
+		echo "$o_ifnames" \
+			| tr ' ' '\n' \
+			| sed "s/.*/-I PREROUTING 1 -i \\0 -p $proto -j ss_rules_pre_src/"
+	fi
+}
 
-flush_rules && ipset_init && ipt_nat && ipt_mangle && export_ipt_rules
-RET=$?
-[ "$RET" = 0 ] || loger 3 "Start failed!"
-exit $RET
+ss_rules_parse_args "$@"
+ss_rules_flush
+ss_rules_ipset_init
+ss_rules_iptchains_init