func (n *IpfsNode) startOnlineServices(ctx context.Context, routingOption RoutingOption, hostOption HostOption, do DiscoveryOption) error {

	if n.PeerHost != nil { // already online.
		return errors.New("node already online")
	}

	// load private key
	if err := n.LoadPrivateKey(); err != nil {
		return err
	}

	// Set reporter
	n.Reporter = metrics.NewBandwidthCounter()

	// get undialable addrs from config
	cfg, err := n.Repo.Config()
	if err != nil {
		return err
	}
	var addrfilter []*net.IPNet
	for _, s := range cfg.Swarm.AddrFilters {
		f, err := mamask.NewMask(s)
		if err != nil {
			return fmt.Errorf("incorrectly formatted address filter in config: %s", s)
		}
		addrfilter = append(addrfilter, f)
	}

	peerhost, err := hostOption(ctx, n.Identity, n.Peerstore, n.Reporter, addrfilter)
	if err != nil {
		return err
	}

	if err := n.startOnlineServicesWithHost(ctx, peerhost, routingOption); err != nil {
		return err
	}

	// Ok, now we're ready to listen.
	if err := startListening(ctx, n.PeerHost, cfg); err != nil {
		return err
	}

	n.Reprovider = rp.NewReprovider(n.Routing, n.Blockstore)
	go n.Reprovider.ProvideEvery(ctx, kReprovideFrequency)

	// setup local discovery
	if do != nil {
		service, err := do(n.PeerHost)
		if err != nil {
			log.Error("mdns error: ", err)
		} else {
			service.RegisterNotifee(n)
			n.Discovery = service
		}
	}

	return n.Bootstrap(DefaultBootstrapConfig)
}

func GenSwarmNetwork(t *testing.T, ctx context.Context) *swarm.Network {
	p := tu.RandPeerNetParamsOrFatal(t)
	ps := peer.NewPeerstore()
	ps.AddPubKey(p.ID, p.PubKey)
	ps.AddPrivKey(p.ID, p.PrivKey)
	n, err := swarm.NewNetwork(ctx, []ma.Multiaddr{p.Addr}, p.ID, ps, metrics.NewBandwidthCounter())
	if err != nil {
		t.Fatal(err)
	}
	ps.AddAddrs(p.ID, n.ListenAddresses(), peer.PermanentAddrTTL)
	return n
}

// New constructs and sets up a new *BasicHost with given Network
func New(net inet.Network, opts ...interface{}) *BasicHost {
	h := &BasicHost{
		network: net,
		mux:     msmux.NewMultistreamMuxer(),
		bwc:     metrics.NewBandwidthCounter(),
	}

	h.proc = goprocess.WithTeardown(func() error {
		if h.natmgr != nil {
			h.natmgr.Close()
		}

		return h.Network().Close()
	})

	// setup host services
	h.ids = identify.NewIDService(h)

	muxh := h.Mux().Handle
	handle := func(s inet.Stream) {
		muxh(s)
	}
	h.relay = relay.NewRelayService(h, handle)

	for _, o := range opts {
		switch o := o.(type) {
		case Option:
			switch o {
			case NATPortMap:
				h.natmgr = newNatManager(h)
			}
		case metrics.Reporter:
			h.bwc = o
		}
	}

	net.SetConnHandler(h.newConnHandler)
	net.SetStreamHandler(h.newStreamHandler)

	return h
}

func makeSwarms(ctx context.Context, t *testing.T, num int) []*Swarm {
	swarms := make([]*Swarm, 0, num)

	for i := 0; i < num; i++ {
		localnp := testutil.RandPeerNetParamsOrFatal(t)

		peerstore := peer.NewPeerstore()
		peerstore.AddPubKey(localnp.ID, localnp.PubKey)
		peerstore.AddPrivKey(localnp.ID, localnp.PrivKey)

		addrs := []ma.Multiaddr{localnp.Addr}
		swarm, err := NewSwarm(ctx, addrs, localnp.ID, peerstore, metrics.NewBandwidthCounter())
		if err != nil {
			t.Fatal(err)
		}

		swarm.SetStreamHandler(EchoStreamHandler)
		swarms = append(swarms, swarm)
	}

	return swarms
}

func TestFilterAddrs(t *testing.T) {

	m := func(s string) ma.Multiaddr {
		maddr, err := ma.NewMultiaddr(s)
		if err != nil {
			t.Fatal(err)
		}
		return maddr
	}

	bad := []ma.Multiaddr{
		m("/ip4/1.2.3.4/udp/1234"),           // unreliable
		m("/ip4/1.2.3.4/udp/1234/sctp/1234"), // not in manet
		m("/ip4/1.2.3.4/udp/1234/utp"),       // utp is broken
		m("/ip4/1.2.3.4/udp/1234/udt"),       // udt is broken on arm
		m("/ip6/fe80::1/tcp/0"),              // link local
		m("/ip6/fe80::100/tcp/1234"),         // link local
	}

	good := []ma.Multiaddr{
		m("/ip4/127.0.0.1/tcp/0"),
		m("/ip6/::1/tcp/0"),
	}

	goodAndBad := append(good, bad...)

	// test filters

	for _, a := range bad {
		if addrutil.AddrUsable(a, true) {
			t.Errorf("addr %s should be unusable", a)
		}
	}

	for _, a := range good {
		if !addrutil.AddrUsable(a, true) {
			t.Errorf("addr %s should be usable", a)
		}
	}

	subtestAddrsEqual(t, addrutil.FilterUsableAddrs(bad), []ma.Multiaddr{})
	subtestAddrsEqual(t, addrutil.FilterUsableAddrs(good), good)
	subtestAddrsEqual(t, addrutil.FilterUsableAddrs(goodAndBad), good)

	// now test it with swarm

	id, err := testutil.RandPeerID()
	if err != nil {
		t.Fatal(err)
	}

	ps := peer.NewPeerstore()
	ctx := context.Background()

	if _, err := NewNetwork(ctx, bad, id, ps, metrics.NewBandwidthCounter()); err == nil {
		t.Fatal("should have failed to create swarm")
	}

	if _, err := NewNetwork(ctx, goodAndBad, id, ps, metrics.NewBandwidthCounter()); err != nil {
		t.Fatal("should have succeeded in creating swarm", err)
	}
}