setup-geneve-with-ns.sh

setup_local_underlay() {
	sudo ip netns add hostA;
	sudo ip netns add hostB;

	sudo ip link add name vethA type veth peer name vethB;
	sudo ip link set vethA netns hostA;
	sudo ip link set vethB netns hostB;

	# create underlay network "physical"
	sudo ip netns exec hostA ip addr add 192.178.0.1/24 dev vethA;
	sudo ip netns exec hostA ip link set vethA up;
	sudo ip netns exec hostB ip addr add 192.178.0.2/24 dev vethB;
	sudo ip netns exec hostB ip link set vethB up;

	# verify underlay connectivity
	echo "===== verifying underlay connectivity ====="
	sudo ip netns exec hostA ping -c 1 192.178.0.2;
}

setup_geneve_tunnel() {
	sudo ip netns exec hostA ip link add name gnv0 type geneve external;
	sudo ip netns exec hostA ip link set gnv0 up;
	sudo ip netns exec hostA ip addr add 10.0.0.1/24 dev gnv0;

	sudo ip netns exec hostB ip link add name gnv0 type geneve external;
	sudo ip netns exec hostB ip link set gnv0 up;
	sudo ip netns exec hostB ip addr add 10.0.0.2/24 dev gnv0;

	# routing
	# This works, but why?
	# We are saying packets in logical network destined to some CIDR block goes through tunnel
	# to remote endpoint specified.
	sudo ip netns exec hostA ip route add 10.0.0.2/32 encap	ip id 100 dst 192.178.0.2 dev gnv0;
	sudo ip netns exec hostB ip route add 10.0.0.1/32 encap ip id 100 dst 192.178.0.1 dev gnv0;
}

teardown() {
	sudo ip netns delete hostA;
	sudo ip netns delete hostB;
}

show_state() {
	echo "===== HOST A ====="
	sudo ip netns exec hostA ip -d link show gnv0;
	sudo ip netns exec hostA ip -d route;

	echo "===== HOST B ====="
	sudo ip netns exec hostB ip -d link show gnv0;
	sudo ip netns exec hostB ip -d route;
}

verify_routing() {
	echo "===== verifying connectivity ====="
	sudo ip netns exec hostA ping -c 3 10.0.0.2;
	sudo ip netns exec hostB ping -c 3 10.0.0.1;
}

case "$1" in
	--setup)
		set -x
		setup_local_underlay
		setup_geneve_tunnel
		set +x
		show_state
		verify_routing
		;;
	--clean)
		set -x
		teardown
		set +x
		ip a
		ip route
		;;
	*)
		echo "Usage: $0 {--setup|--clean}"
		exit 1
		;;
esac