#!/bin/bash

# name of the ethernet gadget interface on the host
USB_IFACE=${1:-enp0s20f0u1}
USB_IFACE_IP=10.0.0.1
USB_IFACE_NET=10.0.0.0/24
# host interface to use for upstream connection
UPSTREAM_IFACE=${2:-enxe4b97aa99867}

ip addr add $USB_IFACE_IP/24 dev $USB_IFACE
ip link set $USB_IFACE up

iptables -A FORWARD -o $UPSTREAM_IFACE -i $USB_IFACE -s $USB_IFACE_NET -m conntrack --ctstate NEW -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -t nat -F POSTROUTING
iptables -t nat -A POSTROUTING -o $UPSTREAM_IFACE -j MASQUERADE

echo 1 > /proc/sys/net/ipv4/ip_forward