Helps run wine steam (or another program) in a network namespace.

steamns

#!/bin/bash

ns=${ns:-steamns}
veth0=${veth0:-veth0}
veth1=${veth1:-veth1}
addr0=${addr0:-10.1.1.1/24}
addr1=${addr1:-10.1.1.2/24}
sudo=${sudo:-sudo}

dev=${dev:-`ip route show | awk 'NR==1 { print $5 }'`}

echo "Guessing that your interface is $dev"

if [ "`sysctl -n net.ipv4.ip_forward`" = "0" ]; then
	echo "IPv4 forwarding not enabled. Enabling"
	$sudo sysctl net.ipv4.ip_forward=1
fi

iptablerules=(
	"POSTROUTING -t nat -o $dev -j MASQUERADE"
	"FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT"
	"FORWARD -i $veth0 -o $dev -j ACCEPT"
)

if [ "$delete" = "1" ]; then
	echo "Deleting everything"
	for rule in "${iptablerules[@]}"; do
		$sudo iptables -D $rule
	done
	$sudo ip netns del $ns
	exit
fi

for rule in "${iptablerules[@]}"; do
	$sudo iptables -C $rule > /dev/null 2>&1
	if [ "$?" = "1" ]; then
		echo "Rule \"$rule\" doesnt exist. Adding it"
		$sudo iptables -A $rule
	fi
done


ns_exists="0"
for n in `ip netns list`; do
	if [ "$n" = "$ns" ]; then
		ns_exists="1"
		break
	fi
done

if [ "$ns_exists" = "0" ]; then
	echo "Namespace $ns doesn't exist. Creating it"
	$sudo ip link add $veth0 type veth peer name $veth1
	$sudo ip netns add $ns
	
	$sudo ip netns exec $ns ip link set dev lo up
	$sudo ip link set $veth1 netns $ns
	$sudo ip netns exec $ns ip addr add $addr1 dev $veth1
	$sudo ip netns exec $ns ip link set up dev $veth1
	$sudo ip netns exec $ns ip route add default via `echo $addr0 | cut -d / -f 1` dev $veth1
	
	$sudo ip addr add $addr0 dev $veth0
	$sudo ip link set up dev $veth0
fi

$sudo ip netns exec $ns sudo -u $USER "$@"