#!/bin/sh
# miniupnpd integration for firewall3

IPTABLES="/usr/sbin/iptables"
IP6TABLES="/usr/sbin/ip6tables"
IPTARGS="-w 1"

$IPTABLES -t filter -N MINIUPNPD 2>/dev/null
$IPTABLES -t nat -N MINIUPNPD 2>/dev/null
$IPTABLES -t nat -N MINIUPNPD-POSTROUTING 2>/dev/null

[ -x $IP6TABLES ] && $IP6TABLES -t filter -N MINIUPNPD 2>/dev/null

. /lib/functions/network.sh

# helper to insert in chain as penultimate
iptables_prepend_rule() {
	local iptables="$1"
	local table="$2"
	local chain="$3"
	local target="$4"

	$iptables "$IPTARGS" -t "$table" -I "$chain" $($iptables "$IPTARGS" -t "$table" --line-numbers -nL "$chain" | \
		sed -ne '$s/[^0-9].*//p') -j "$target"
}

ADDED=0

add_extzone_rules() {
    local ext_zone="$1"

    [ -z "$ext_zone" ] && return

    # IPv4 - due to NAT, need to add both to nat and filter table
    # need to insert as penultimate rule for input & forward & postrouting since final rule might be a fw3 REJECT
    iptables_prepend_rule "$IPTABLES" filter "zone_${ext_zone}_input" MINIUPNPD
    iptables_prepend_rule "$IPTABLES" filter "zone_${ext_zone}_forward" MINIUPNPD
    $IPTABLES -t nat -A "zone_${ext_zone}_prerouting"  -j MINIUPNPD
    iptables_prepend_rule "$IPTABLES" nat "zone_${ext_zone}_postrouting" MINIUPNPD-POSTROUTING

    # IPv6 if available - filter only
    [ -x $IP6TABLES ] && {
	iptables_prepend_rule "$IP6TABLES" filter "zone_${ext_zone}_input" MINIUPNPD
	iptables_prepend_rule "$IP6TABLES" filter "zone_${ext_zone}_forward" MINIUPNPD
    }
    ADDED=$(($ADDED + 1))
}

# By default, user configuration is king.

for ext_iface in $(uci -q get upnpd.config.external_iface); do
    add_extzone_rules $(fw3 -q network "$ext_iface")
done

add_extzone_rules $(uci -q get upnpd.config.external_zone)

[ "$ADDED" -ne 0 ] && exit 0

# If really nothing is available, resort to network_find_wan{,6} and
# assume external interfaces all have same firewall zone.

# (This heuristic may fail horribly, in case of e.g. multihoming, so
# please set external_zone in that case!)

network_find_wan wan_iface
network_find_wan6 wan6_iface

for ext_iface in $wan_iface $wan6_iface; do
    # fw3 -q network fails on sub-interfaces => map to device first
    network_get_device ext_device $ext_iface
    add_extzone_rules $(fw3 -q device "$ext_device")
done