#!/bin/sh -e # # Copyright (C) 2017 Yousong Zhou # # The design idea was derived from ss-rules by Jian Chang # # This is free software, licensed under the GNU General Public License v3. # See /LICENSE for more information. # ss_rules_usage() { cat >&2 < Local port number of ss-redir with TCP mode -L Local port number of ss-redir with UDP mode -s List of ip addresses of remote shadowsocks server --ifnames Only apply rules on packets from these ifnames --src-bypass --src-forward --src-checkdst --src-default 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 --dst-forward --dst-bypass-file --dst-forward-file --dst-default Same as with their --src-xx equivalent --dst-forward-recentrst Forward those packets whose destinations have recently sent to us multiple tcp-rst packets --local-default 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 } 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: $*" >&2 } ss_rules_parse_args() { while [ "$#" -gt 0 ]; do case "$1" in -h|--help) ss_rules_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-forward-recentrst) o_dst_forward_recentrst=1; shift 1;; --dst-bypass-file) o_dst_bypass_file="$2"; shift 2;; --dst-forward-file) o_dst_forward_file="$2"; shift 2;; *) __errmsg "unknown option $1"; return 1;; esac done if [ -z "$o_redir_tcp_port" -a -z "$o_redir_udp_port" ]; then __errmsg "Requires at least -l or -L option" return 1 fi if [ -n "$o_dst_forward_recentrst" ] && ! iptables -m recent -h >/dev/null; then __errmsg "Please install iptables-mod-conntrack-extra with opkg" return 1 fi o_remote_servers="$(for s in $o_remote_servers; do resolveip -4 "$s"; done)" } 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 } 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 create ss_rules_dst_forward_recentrst_ hash:ip hashsize 64 timeout 3600 $(ss_rules_ipset_mkadd ss_rules_dst_bypass_ "$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 } ss_rules_ipset_mkadd() { local setname="$1"; shift local i for i in $*; do echo "add $setname $i" done } ss_rules_iptchains_init() { ss_rules_iptchains_init_tcp ss_rules_iptchains_init_udp } ss_rules_iptchains_init_tcp() { local local_target [ -n "$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: $o_local_default" COMMIT EOF } ss_rules_iptchains_init_udp() { [ -n "$o_redir_udp_port" ] || return 0 ss_rules_iptchains_init_ mangle udp } ss_rules_iptchains_init_() { local table="$1" local proto="$2" local forward_rules local src_default_target dst_default_target local recentrst_mangle_rules recentrst_addset_rules case "$proto" in tcp) forward_rules="-A ss_rules_forward -p tcp -j REDIRECT --to-ports $o_redir_tcp_port" if [ -n "$o_dst_forward_recentrst" ]; then recentrst_mangle_rules=" *mangle -I PREROUTING 1 -p tcp -m tcp --tcp-flags RST RST -m recent --name ss_rules_recentrst --set --rsource COMMIT " recentrst_addset_rules=" -A ss_rules_dst -m recent --name ss_rules_recentrst --rcheck --rdest --seconds 3 --hitcount 3 -j SET --add-set ss_rules_dst_forward_recentrst_ dst --exist -A ss_rules_dst -m set --match-set ss_rules_dst_forward_recentrst_ dst -j ss_rules_forward " fi ;; 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 "$o_redir_udp_port" --tproxy-mark 0x01/0x01" ;; esac case "$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 "$o_dst_default" in forward) dst_default_target=ss_rules_forward ;; bypass|*) dst_default_target=RETURN ;; esac sed -e '/^\s*$/d' -e 's/^\s\+//' <<-EOF | iptables-restore --noflush *$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 $recentrst_addset_rules -A ss_rules_dst -j $dst_default_target -m comment --comment "dst_default: $o_dst_default" $forward_rules COMMIT $recentrst_mangle_rules EOF } ss_rules_iptchains_mkprerules() { local proto="$1" if [ -z "$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 $proto -j ss_rules_pre_src/" fi } ss_rules_parse_args "$@" ss_rules_flush ss_rules_ipset_init ss_rules_iptchains_init