$ cat  package/base-files/files/etc/hotplug.d/iface/98-pbridge.sh
WIF=$DEVICE
LIF=br-lan
IFCONFIG=/sbin/ifconfig
ROUTE=/sbin/route
IPTABLES=/usr/sbin/iptables
TMP_DIR=/tmp/tmp_file
TMP_PBRIDGE_IP="$TMP_DIR/pbridge_IP"
FWT="$TMP_DIR/pbridge_firewall.sh"
DNS_TC="$TMP_DIR/dnsmasq_pbridge.conf"
mkdir -p "$TMP_DIR"

get_wan_section() {
        NAME=`uci get network.wan.ifname`
        SECTION="wan"
        if [ "$NAME" == "3g-ppp" ]; then
                #3g-ppp gets its IP individually, it does not reflect in wan IP
                SECTION="ppp"
        elif [ "$NAME" == "wwan0" ]; then
                SECTION="ppp_dhcp"
        fi

        echo "$SECTION"
}

get_new_address() {
        local p=`uci -q get network.lan.ipaddr`

        temp=`echo $p|awk -F '.' '{print $1"."$2"."$3}'`
        for i in `seq 245 254`; do
                addr="$temp.$i"
                ping temp -c1 -W1
                if [ "$?" -eq "1" ]; then
                        break
                else
                        continue
                fi
        done
        echo $addr
}

EXTERNAL=

pseudo_bridge()
{
        . /lib/functions/network.sh
        . /lib/teltonika-functions.sh
        network_flush_cache
        network_get_ipaddr WIP "$INTERFACE"
        network_get_gateway WGW "$INTERFACE"
        network_get_subnet SUBNET "$INTERFACE"
        if [ -z "$WIP" -o -z "$WGW" -o -z "$SUBNET"  ]; then
                return 1
        fi
        OLDWIP=`cat $TMP_PBRIDGE_IP 2>/dev/null`

        echo "$WIP" >"$TMP_PBRIDGE_IP"
        WNM=`ipcalc.sh $SUBNET | grep "NETMASK" | awk -F '=' '{print $2}'`
        #/etc/init.d/dnsmasq stop

        LIP=`uci get network.lan.ipaddr`
        LNM=`uci get network.lan.netmask`
        PROTO=`uci get network.ppp.proto`

        echo "$IPTABLES -t nat -D zone_wan_postrouting -j MASQUERADE" > "$FWT"
        echo "$IPTABLES -t nat -A zone_wan_postrouting -s $LIP/$LNM -o $WIF -j SNAT --to-source $WIP" >> "$FWT"
        chmod +x "$FWT"

        $IFCONFIG $LIF:0 down
        if [ "$OLDWIP" != "$WIP" ]; then
                ifup lan
        fi
        #       remove WAN IF IP

        # Laikinai isjungti interneto adapteri, kad sekmingai butu leasinamas IP adresas
        $IFCONFIG $WIF `get_new_address` up

        #       replace default route to Gateway through WIF
        $ROUTE add -host $WGW dev $WIF
        $ROUTE add default gw $WGW dev $WIF
        #       add route to WAN IP through LAN iface
        $ROUTE add -host $WIP dev $LIF
        # enable proxy_arp so can use WGW s gateway on LAN device
        echo "1" >/proc/sys/net/ipv4/conf/$WIF/proxy_arp
        echo "1" >/proc/sys/net/ipv4/conf/$LIF/proxy_arp
        if [ $(get_vidpid_tlt) = "12D1:15C1" ]; then
                /sbin/arp -s $WGW 00:00:00:00:00:00
        fi

        #       replace MASQ on WIF with SNAT
        #iptables -F
        #iptables -t nat -F
        #iptables -t raw -F
        #iptables -t mangle -F
        #iptables -P FORWARD ACCEPT
        #$IPTABLES -t nat -D zone_wan_postrouting -j MASQUERADE
        #$IPTABLES -t nat -A zone_wan_postrouting -s $LIP/$LNM -o $WIF -j SNAT --to-source $WIP
        #echo "$IPTABLES -t nat -D zone_wan_postrouting -j MASQUERADE" > "$FWT"
        #echo "$IPTABLES -t nat -A zone_wan_postrouting -s $LIP/$LNM -o $WIF -j SNAT --to-source $WIP" >> "$FWT"
        #chmod +x "$FWT"
        #       add a bit of extra firewall
        #$IPTABLES -t nat -I PREROUTING -i $WIF -d ! $WIP -j DROP
        #       intercept HTTP port
        #logger -t MANO "MANO=======$IPTABLES -t nat -A PREROUTING -i $WIF -p tcp --dport 80 -j DNAT --to $LIP"
        #$IPTABLES -t nat -A PREROUTING -i $WIF -p tcp --dport 80 -j DNAT --to $LIP

        #       setup DHCP server
        #       set WAN GW as secondary LAN IP for DHCP to work
        #$IFCONFIG $LIF:0 $WGW netmask $WNM


        passthrough_dhcp=`uci get -q network.ppp.passthrough_dhcp`
        if [ "$passthrough_dhcp" != "no_dhcp" ]; then # nevykdom kai passthrough dhcp mode yra no DHCP
                if [ "$PROTO" == "3g" ]; then
                        # Workaround
                        new_WGW=`echo $WIP | awk -F '.' '{print $1"."$2"."$3}'`
                        WNM="255.255.255.0"

                        if [ "$WGW" != "$new_WGW.1" ] && [ "$WIP" != "$new_WGW.1" ]; then
                                new_WGW="$new_WGW.1"
                        elif [ "$WGW" != "$new_WGW.2" ] && [ "$WIP" != "$new_WGW.2" ]; then
                                new_WGW="$new_WGW.2"
                        else
                                new_WGW="$new_WGW.3"
                        fi
                else
                        local still_not_found=0
                        local new_WGW=`echo $WIP | awk -F '.' '{print $1"."$2"."$3}'`
                        local END_GW=`echo $WGW | cut -d "." -f 4`
                        NET_IP=`ipcalc.sh $WIP $WNM | grep "NETWORK" | awk -F '=' '{print $2}'`
                        BCAST_IP=`ipcalc.sh $WIP $WNM | grep "BROADCAST" | awk -F '=' '{print $2}'`
                        while [ "$WGW" == "$new_WGW.$END_GW" ] || [ "$WIP" == "$new_WGW.$END_GW" ] || [ "$NET_IP" == "$new_WGW.$END_GW" ]; do
                                if [ "$NET_IP" == "$new_WGW.$END_GW" ] && [ $still_not_found == 0 ]; then
                                        END_GW=`echo $BCAST_IP | cut -d "." -f 4`
                                        still_not_found=1
                                elif [ "$NET_IP" == "$new_WGW.$END_GW" ] && [ $still_not_found == 1 ]; then
                                        local PREFIX=`ipcalc.sh $SUBNET | grep "PREFIX" | awk -F '=' '{print $2}'`
                                        PREFIX=$((PREFIX-1))
                                        SUBNET="$WIP/$PREFIX"
                                        WNM=`ipcalc.sh $SUBNET | grep "NETMASK" | awk -F '=' '{print $2}'`
                                        NET_IP=`ipcalc.sh $WIP $WNM | grep "NETWORK" | awk -F '=' '{print $2}'`
                                        BCAST_IP=`ipcalc.sh $WIP $WNM | grep "BROADCAST" | awk -F '=' '{print $2}'`
                                        END_GW=`echo $BCAST_IP | cut -d "." -f 4`
                                fi
                                END_GW=$((END_GW-1))
                        done
                        new_WGW="$new_WGW.$END_GW"
                fi

                $IFCONFIG $LIF:0 $new_WGW netmask $WNM
        fi


        #       setup DHCP config

        #/etc/init.d/dnsmasq stop
        #killall dnsmasq
        #rm /tmp/dhcp.leases
        #cp /var/etc/dnsmasq.conf "$DNS_TC"
        #sed -i "/dhcp-range/d" "$DNS_TC"
        rm -f "$DNS_TC"
        #echo "dhcp-range=lan,$WIP,$WIP,$WNM,12h" >> "$DNS_TC"
        #echo "dhcp-range=lan,192.168.1.160,192.168.1.200,255.255.255.0,12h" >> "$DNS_TC"
        #echo "dhcp-range=lan,$WIP,$WIP,$WNM,12h" >> "$DNS_TC"
        if [ "$passthrough_dhcp" != "no_dhcp" ]; then
                leasetime=`uci get -q network.ppp.leasetime`
                echo "dhcp-range=lan,$WIP,$WIP,$WNM,$leasetime" >> "$DNS_TC"

                DMAC=`uci get -q network.ppp.mac`
                if [ "$DMAC" ]; then
                        #echo "dhcp-host=$DMAC,192.168.1.151,24h" >> "$DNS_TC"
                        echo "dhcp-host=$DMAC,$WIP,12h" >> "$DNS_TC"
                fi
                /etc/init.d/dnsmasq restart
        fi
        /etc/init.d/firewall reload
}

if [ "$DEVICE" == "eth2" ] || [ "$DEVICE" == "3g-ppp" ] || [ "$DEVICE" == "wwan0" ]; then
        ppp_method=`uci get -q network.ppp.method`
        ppp_enabled=`uci get -q network.ppp.enabled`
        if [ "$ppp_method" == "pbridge" ] && [ "$ppp_enabled" != "0" ]; then
                if [ "$ACTION" == "ifup" -o "$ACTION" == "ifupdate" ]; then
                        #logger -t MANO "Darom"
                        pseudo_bridge
                        if [ "$ACTION" == "ifupdate" ]; then
                                $IFCONFIG $WIF `get_new_address` up
                        fi
                elif [ "$ACTION" == "ifdown" ]; then
                        $IFCONFIG $LIF:0 down
                        rm -f "$DNS_TC"
                fi
        fi
fi