tools/netusb.sh

#!/bin/bash

#****************************************************************************
# tools/netusb.sh
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.  The
# ASF licenses this file to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance with the
# License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
# License for the specific language governing permissions and limitations
# under the License.
#
#****************************************************************************

# USB Ethernet Gadget interface helper script - sets up nuttx to access
# the internet via a host route and IP Tables.

IP_NET="10.0.0.0/24"
IP_NETMASK="255.255.255.0"
IP_BROADCAST="10.0.0.255"
IP_HOST="10.0.0.1"
IP_NUTTX="10.0.0.2"

if [ $# != 3 ]; then
  echo "Usage: $0 <main-interface> <usb-net-interface> <on|off>"
  exit 1
fi

IF_HOST=$1
IF_USB=$2
STATUS=$3

net_off() {
  ip route delete $IP_NET
  ip route delete $IP_NUTTX/32

  # delete nat rules to clean up
  iptables -t nat -D POSTROUTING -o $IF_HOST -j MASQUERADE
  iptables -D FORWARD -i $IF_HOST -o $IF_USB -m state --state RELATED,ESTABLISHED -j ACCEPT
  iptables -D FORWARD -i $IF_USB -o $IF_HOST -j ACCEPT

  ip route show
  ifconfig $IF_USB down
}

if [ "$STATUS" == "on" ]; then
  net_off
  ifconfig $IF_USB up
  ifconfig -a
  ifconfig $IF_USB add $IP_HOST
  ifconfig $IF_USB:0 broadcast $IP_BROADCAST netmask $IP_NETMASK
  ip route add $IP_NET dev $IF_USB src $IP_HOST
  ip route add $IP_NUTTX/32 dev $IF_USB src $IP_HOST

  # nat to allow NuttX to access the internet
  iptables -t nat -A POSTROUTING -o $IF_HOST -j MASQUERADE
  iptables -A FORWARD -i $IF_HOST -o $IF_USB -m state --state RELATED,ESTABLISHED -j ACCEPT
  iptables -A FORWARD -i $IF_USB -o $IF_HOST -j ACCEPT

  ip route show
else
  net_off
fi