Method SetupNetworking

tailnet/test/integration/network.go:424–545

SetupNetworking creates multiple namespaces with a central router in the following topology . . ┌──────────────┐ . │ │ . │ Server ├─────────────────────────────────────┐ . │ │fdac:38fa:ffff:3::2 │ . └──────────────┘

(t *testing.T, l slog.Logger)

// .   └──────────────┘
// The veth link between Client 1 and the router has a configurable MTU via Client1MTU.
func (n TriangleNetwork) SetupNetworking(t *testing.T, l slog.Logger) TestNetworking {
	logger := l.Named("setup-networking").Leveled(slog.LevelDebug)
	t.Helper()
	var (
		namePrefix = uniqNetName(t) + "_"
		network    = fakeTriangleNetwork{
			NamePrefix: namePrefix,
		}
		// Unique Local Address prefix
		ula = "fdac:38fa:ffff:"
	)

	// Create three network namespaces for server, client1, and client2
	network.ServerNetNS = createNetNS(t, namePrefix+"server")
	network.Client1NetNS = createNetNS(t, namePrefix+"client1")
	network.Client2NetNS = createNetNS(t, namePrefix+"client2")
	network.RouterNetNS = createNetNS(t, namePrefix+"router")

	// Create veth pair between server and router
	network.ServerVethPair = vethPair{
		Outer: namePrefix + "s-r",
		Inner: namePrefix + "r-s",
	}
	err := createVethPair(network.ServerVethPair.Outer, network.ServerVethPair.Inner)
	require.NoErrorf(t, err, "create veth pair %q <-> %q",
		network.ServerVethPair.Outer, network.ServerVethPair.Inner)

	// Move server-router veth ends to their respective namespaces
	err = setVethNetNS(network.ServerVethPair.Outer, int(network.ServerNetNS.Fd()))
	require.NoErrorf(t, err, "set veth %q to server NetNS", network.ServerVethPair.Outer)
	err = setVethNetNS(network.ServerVethPair.Inner, int(network.RouterNetNS.Fd()))
	require.NoErrorf(t, err, "set veth %q to router NetNS", network.ServerVethPair.Inner)

	// Create veth pair between client1 and router
	network.Client1VethPair = vethPair{
		Outer: namePrefix + "1-r",
		Inner: namePrefix + "r-1",
	}
	logger.Debug(context.Background(), "creating client1 link", slog.F("mtu", n.Client1MTU))
	err = createVethPair(network.Client1VethPair.Outer, network.Client1VethPair.Inner, withMTU(n.Client1MTU))
	require.NoErrorf(t, err, "create veth pair %q <-> %q",
		network.Client1VethPair.Outer, network.Client1VethPair.Inner)

	// Move client1-router veth ends to their respective namespaces
	err = setVethNetNS(network.Client1VethPair.Outer, int(network.Client1NetNS.Fd()))
	require.NoErrorf(t, err, "set veth %q to server NetNS", network.Client1VethPair.Outer)
	err = setVethNetNS(network.Client1VethPair.Inner, int(network.RouterNetNS.Fd()))
	require.NoErrorf(t, err, "set veth %q to client2 NetNS", network.Client1VethPair.Inner)

	// Create veth pair between client1 and client2
	network.Client2VethPair = vethPair{
		Outer: namePrefix + "2-r",
		Inner: namePrefix + "r-2",
	}

	err = createVethPair(network.Client2VethPair.Outer, network.Client2VethPair.Inner)
	require.NoErrorf(t, err, "create veth pair %q <-> %q",
		network.Client2VethPair.Outer, network.Client2VethPair.Inner)