Function createFakeInternet

tailnet/test/integration/network.go:255–389

createFakeInternet creates multiple namespaces with veth pairs between them with the following topology: . veth ┌────────┐ veth . ┌─────────────────┤ Bridge ├───────────────────┐ . │ └───┬────┘ │ . │

(t *testing.T)

// box. Default routes are created from the edge namespaces (client1, client2)
// to their respective routers, but no NAT rules are created.
func createFakeInternet(t *testing.T) fakeInternet {
	t.Helper()
	const (
		bridgePrefix  = "10.0.0."
		serverIP      = bridgePrefix + "1"
		client1Prefix = "10.0.2."
		client2Prefix = "10.0.3."
	)
	var (
		namePrefix = uniqNetName(t) + "_"
		router     = fakeInternet{
			NamePrefix: namePrefix,
			BridgeName: namePrefix + "b",
		}
	)

	// Create bridge namespace and bridge interface.
	router.BridgeNetNS = createNetNS(t, router.BridgeName)
	err := createBridge(router.BridgeNetNS, router.BridgeName)
	require.NoError(t, err, "create bridge in netns")

	// Create server namespace and veth pair between bridge and server.
	router.ServerNetNS = createNetNS(t, namePrefix+"s")
	router.ServerVethPair = vethPair{
		Outer: namePrefix + "b-s",
		Inner: namePrefix + "s-b",
	}
	err = joinBridge(joinBridgeOpts{
		bridgeNetNS: router.BridgeNetNS,
		netNS:       router.ServerNetNS,
		bridgeName:  router.BridgeName,
		vethPair:    router.ServerVethPair,
		ip:          serverIP,
	})
	require.NoError(t, err, "join bridge with server")

	leaves := []struct {
		leaf           *fakeRouterLeaf
		routerName     string
		clientName     string
		routerBridgeIP string
		routerClientIP string
		clientIP       string
	}{
		{
			leaf:           &router.Client1,
			routerName:     "c1r",
			clientName:     "c1",
			routerBridgeIP: bridgePrefix + "2",
			routerClientIP: client1Prefix + "1",
			clientIP:       client1Prefix + "2",
		},
		{
			leaf:           &router.Client2,
			routerName:     "c2r",
			clientName:     "c2",
			routerBridgeIP: bridgePrefix + "3",
			routerClientIP: client2Prefix + "1",