. /lib/functions/network.sh

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

QNUM=200
TPPORT_HTTP=1188
TPPORT_HTTPS=1189
TPWS_USER=daemon
[ -n "$DESYNC_MARK" ] || DESYNC_MARK=0x40000000

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

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

CUSTOM_SCRIPT="$ZAPRET_BASE/init.d/openwrt/custom"
[ -f "$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
}


# can be multiple ipv6 outgoing interfaces
# uplink from isp, tunnelbroker, vpn, ...
# want them all. who knows what's the real one that blocks sites
# dont want any manual configuration - want to do it automatically
# standard network_find_wan[6] return only the first
# we use low level function from network.sh to avoid this limitation
# it can change theoretically and stop working

network_find_wan_all()
{
 __network_ifstatus "$1" "" "[@.route[@.target='0.0.0.0' && !@.table]].interface" "" 10 2>/dev/null && return
 network_find_wan $1
}
network_find_wan6_all()
{
 __network_ifstatus "$1" "" "[@.route[@.target='::' && !@.table]].interface" "" 10 2>/dev/null && return
 network_find_wan6 $1
}

ipt()
{
 iptables -C "$@" 2>/dev/null || iptables -I "$@"
}
ipt6()
{
 ip6tables -C "$@" 2>/dev/null || ip6tables -I "$@"
}

# 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
 if exists ip ; then
    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
 else
    ifconfig $1 | sed -re 's/^.*inet6 addr: ([^ ]*)\/[0-9]* Scope:Link.*$/\1/;t;d' | head -n 1
 fi
}
get_ipv6_global()
{
 # $1 - interface name. if empty - any interface
 if exists ip ; then
    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
 else
    ifconfig $1 | sed -re 's/^.*inet6 addr: ([^ ]*)\/[0-9]* Scope:Global.*$/\1/;t;d' | head -n 1
 fi
}

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" ] || {
    # no reason to query if its down
    network_is_up lan || return

    local DEVICE
    network_get_device DEVICE lan

    local ct=0
    while 
      DNAT6_TARGET=$(get_ipv6_linklocal $DEVICE)
      [ -n "$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 $DEVICE)
      [ -n "$DNAT6_TARGET" ] || {
        echo could not get any address
        DNAT6_TARGET=-
      }
    }
 }
}


fw_nfqws_pre4()
{
 # $1 - filter ipv4
 # $2 - queue number

 local DEVICE wan_iface

 [ "$DISABLE_IPV4" = "1" ] || {
    network_find_wan_all wan_iface
    for ext_iface in $wan_iface; do
       network_get_device DEVICE $ext_iface
       ipt PREROUTING -t mangle -i $DEVICE -p tcp $1 $IPSET_EXCLUDE src -j NFQUEUE --queue-num $2 --queue-bypass
    done
 }
}
fw_nfqws_pre6()
{
 # $1 - filter ipv6
 # $2 - queue number

 local DEVICE wan_iface

 [ "$DISABLE_IPV6" = "1" ] || {
    network_find_wan6_all wan_iface
    for ext_iface in $wan_iface; do
       network_get_device DEVICE $ext_iface
       ipt6 PREROUTING -t mangle -i $DEVICE -p tcp $1 $IPSET_EXCLUDE6 src -j NFQUEUE --queue-num $2 --queue-bypass
    done
 }
}
fw_nfqws_pre()
{
 # $1 - filter ipv4
 # $2 - filter ipv6
 # $3 - queue number

 fw_nfqws_pre4 "$1" $3
 fw_nfqws_pre6 "$2" $3
}
fw_nfqws_post4()
{
 # $1 - filter ipv4
 # $2 - queue number

 local DEVICE wan_iface

 [ "$DISABLE_IPV4" = "1" ] || {
    network_find_wan_all wan_iface
    for ext_iface in $wan_iface; do
       network_get_device DEVICE $ext_iface
       ipt POSTROUTING -t mangle -o $DEVICE -p tcp $1 $IPSET_EXCLUDE dst -j NFQUEUE --queue-num $2 --queue-bypass
    done
 }
}
fw_nfqws_post6()
{
 # $1 - filter ipv6
 # $2 - queue number

 local DEVICE wan_iface

 [ "$DISABLE_IPV6" = "1" ] || {
    network_find_wan6_all wan_iface
    for ext_iface in $wan_iface; do
       network_get_device DEVICE $ext_iface
       ipt6 POSTROUTING -t mangle -o $DEVICE -p tcp $1 $IPSET_EXCLUDE6 dst -j NFQUEUE --queue-num $2 --queue-bypass
    done
 }
}
fw_nfqws_post()
{
 # $1 - filter ipv4
 # $2 - filter ipv6
 # $3 - queue number

 fw_nfqws_post4 "$1" $3
 fw_nfqws_post6 "$2" $3
}


IPT_OWNER="-m owner ! --uid-owner $TPWS_USER"
fw_tpws4()
{
 # $1 - filter ipv6
 # $2 - tpws port

 local DEVICE wan_iface
 
 [ "$DISABLE_IPV4" = "1" ] || {
    network_find_wan_all wan_iface
    for ext_iface in $wan_iface; do
       network_get_device DEVICE $ext_iface
       ipt OUTPUT -t nat -o $DEVICE $IPT_OWNER -p tcp $1 $IPSET_EXCLUDE dst -j DNAT --to 127.0.0.1:$2
    done
    ipt prerouting_lan_rule -t nat -p tcp $1 $IPSET_EXCLUDE dst -j DNAT --to 127.0.0.1:$2
    network_get_device DEVICE lan
    sysctl -qw net.ipv4.conf.$DEVICE.route_localnet=1
 }
}
fw_tpws6()
{
 # $1 - filter ipv6
 # $2 - tpws port

 local DEVICE wan_iface
 
 [ "$DISABLE_IPV6" = "1" ] || {
    network_find_wan6_all wan_iface
    for ext_iface in $wan_iface; do
       network_get_device DEVICE $ext_iface
       ipt6 OUTPUT -t nat -o $DEVICE $IPT_OWNER -p tcp $1 $IPSET_EXCLUDE6 dst -j DNAT --to [::1]:$2
    done
    network_get_device DEVICE lan
    dnat6_target
    [ "$DNAT6_TARGET" != "-" ] && ipt6 PREROUTING -t nat -i $DEVICE -p tcp $1 $IPSET_EXCLUDE6 dst -j DNAT --to [$DNAT6_TARGET]:$2
 }
}
fw_tpws()
{
 # $1 - filter ipv4
 # $2 - filter ipv6
 # $3 - tpws port

 fw_tpws4 "$1" $3
 fw_tpws6 "$2" $3
}


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


zapret_apply_firewall()
{
	local rule
	local synack="--tcp-flags SYN,ACK SYN,ACK"
	local ipset_zapret="-m set --match-set zapret"
	local ipset_zapret6="-m set --match-set zapret6"
	local desync="-m multiport --dports 80,443 -m connbytes --connbytes-dir=original --connbytes-mode=packets --connbytes 2:4 -m mark ! --mark $DESYNC_MARK/$DESYNC_MARK"

	# always create ipsets. ip_exclude ipset is required
	create_ipset no-update

	case "${MODE}" in
	    tpws_hostlist|tpws_all)
			fw_tpws "--dport 80" "--dport 80" $TPPORT_HTTP
			;;
	    tpws_ipset)
			fw_tpws "--dport 80 $ipset_zapret dst" "--dport 80 $ipset_zapret6 dst" $TPPORT_HTTP
			;;
	    tpws_ipset_https)
			fw_tpws "--dport 80 $ipset_zapret dst" "--dport 80 $ipset_zapret6 dst" $TPPORT_HTTP
			fw_tpws "--dport 443 $ipset_zapret dst" "--dport 443 $ipset_zapret6 dst" $TPPORT_HTTPS
			;;
	    tpws_all_https)
			fw_tpws "--dport 80" "--dport 80" $TPPORT_HTTP
			fw_tpws "--dport 443" "--dport 443" $TPPORT_HTTPS
			;;
	    nfqws_all_desync|nfqws_hostlist_desync)
			fw_nfqws_post "$desync" "$desync" $QNUM
			;;
	    nfqws_ipset_desync)
			fw_nfqws_post "$desync $ipset_zapret dst" "$desync $ipset_zapret6 dst" $QNUM
			;;
	    custom)
	    		existf zapret_custom_firewall && zapret_custom_firewall
			;;
	esac
}