OpenWRT's OpenVPN

script-security 2
up /etc/openvpn/client.sh
down /etc/openvpn/client.sh

#!/bin/sh
env | sed -n -e "
/^foreign_option_.*=dhcp-option.*DNS/s//nameserver/p
/^foreign_option_.*=dhcp-option.*DOMAIN/s//search/p
" | sort -u > /tmp/resolv.conf.vpn
case ${script_type} in
(up) uci set dhcp.@dnsmasq[0].resolvfile="/tmp/resolv.conf.vpn" ;;
(down) uci set dhcp.@dnsmasq[0].resolvfile="/tmp/resolv.conf.auto" ;;
esac
/etc/init.d/dnsmasq restart &

chmod +x /etc/openvpn/client.sh

opkg install openvpn-openssl luci-app-openvpn openvpn-easy-rsa

Enable incoming OpenVPN connections:

uci add firewall rule
uci set firewall.@rule[-1]._name=openvpn
uci set firewall.@rule[-1].src=wan
uci set firewall.@rule[-1].target=ACCEPT
uci set firewall.@rule[-1].proto=udp
uci set firewall.@rule[-1].dest_port=1194
uci commit firewall
 
echo "iptables -I OUTPUT -o tap+ -j ACCEPT" >> /etc/firewall.user
echo "iptables -I INPUT -i tap+ -j ACCEPT" >> /etc/firewall.user
echo "iptables -I FORWARD -o tap+ -j ACCEPT" >> /etc/firewall.user
echo "iptables -I FORWARD -i tap+ -j ACCEPT" >> /etc/firewall.user

mkdir -o /etc/openvpn
uci set openvpn.uservpn=openvpn
uci set openvpn.uservpn.config=/etc/openvpn/user-vpn.conf
uci set openvpn.uservpn.enable=1
uci commit openvpn

cat > /etc/openvpn/user-vpn.conf

 port 1194
 proto udp
 dev tap0
 keepalive 10 120
 status /tmp/openvpn-status.log
 verb 3
 secret /etc/openvpn/secret.key

Add VPN to local LAN bridge:

cat > /etc/init.d/openvpn-bridge
#!/bin/sh /etc/rc.common
 
    START=94
 
    start() {
        openvpn --mktun --dev tap0
        brctl addif br-lan tap0
        ifconfig tap0 0.0.0.0 promisc up
    }
 
    stop() {
        ifconfig tap0 0.0.0.0 down
        brctl delif br-lan tap0
        openvpn --rmtun --dev tap0
    }
 
 
chmod 755 /etc/init.d/openvpn-bridge 
/etc/init.d/openvpn-bridge enable
/etc/init.d/openvpn-bridge start

openvpn --genkey --secret /etc/openvpn/secret.key

Start VPN:

/etc/init.d/openvpn enable
/etc/init.d/openvpn start