kubo/core/commands/swarm.go

package commands

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"path"
	"sort"
	"strconv"
	"sync"
	"text/tabwriter"
	"time"

	"github.com/ipfs/kubo/commands"
	"github.com/ipfs/kubo/config"
	"github.com/ipfs/kubo/core/commands/cmdenv"
	"github.com/ipfs/kubo/core/node/libp2p"
	"github.com/ipfs/kubo/repo"
	"github.com/ipfs/kubo/repo/fsrepo"

	cmds "github.com/ipfs/go-ipfs-cmds"
	ic "github.com/libp2p/go-libp2p/core/crypto"
	inet "github.com/libp2p/go-libp2p/core/network"
	"github.com/libp2p/go-libp2p/core/peer"
	pstore "github.com/libp2p/go-libp2p/core/peerstore"
	rcmgr "github.com/libp2p/go-libp2p/p2p/host/resource-manager"
	ma "github.com/multiformats/go-multiaddr"
	madns "github.com/multiformats/go-multiaddr-dns"
	mamask "github.com/whyrusleeping/multiaddr-filter"
)

const (
	dnsResolveTimeout = 10 * time.Second
)

type stringList struct {
	Strings []string
}

type addrMap struct {
	Addrs map[string][]string
}

var SwarmCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Interact with the swarm.",
		ShortDescription: `
'ipfs swarm' is a tool to manipulate the network swarm. The swarm is the
component that opens, listens for, and maintains connections to other
ipfs peers in the internet.
`,
	},
	Subcommands: map[string]*cmds.Command{
		"addrs":      swarmAddrsCmd,
		"connect":    swarmConnectCmd,
		"disconnect": swarmDisconnectCmd,
		"filters":    swarmFiltersCmd,
		"peers":      swarmPeersCmd,
		"peering":    swarmPeeringCmd,
		"resources":  swarmResourcesCmd, // libp2p Network Resource Manager

	},
}

const (
	swarmVerboseOptionName           = "verbose"
	swarmStreamsOptionName           = "streams"
	swarmLatencyOptionName           = "latency"
	swarmDirectionOptionName         = "direction"
	swarmResetLimitsOptionName       = "reset"
	swarmUsedResourcesPercentageName = "min-used-limit-perc"
	swarmIdentifyOptionName          = "identify"
)

type peeringResult struct {
	ID     peer.ID
	Status string
}

var swarmPeeringCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Modify the peering subsystem.",
		ShortDescription: `
'ipfs swarm peering' manages the peering subsystem.
Peers in the peering subsystem are maintained to be connected, reconnected
on disconnect with a back-off.
The changes are not saved to the config.
`,
	},
	Subcommands: map[string]*cmds.Command{
		"add": swarmPeeringAddCmd,
		"ls":  swarmPeeringLsCmd,
		"rm":  swarmPeeringRmCmd,
	},
}

var swarmPeeringAddCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Add peers into the peering subsystem.",
		ShortDescription: `
'ipfs swarm peering add' will add the new address to the peering subsystem as one that should always be connected to.
`,
	},
	Arguments: []cmds.Argument{
		cmds.StringArg("address", true, true, "address of peer to add into the peering subsystem"),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		addrs := make([]ma.Multiaddr, len(req.Arguments))

		for i, arg := range req.Arguments {
			addr, err := ma.NewMultiaddr(arg)
			if err != nil {
				return err
			}

			addrs[i] = addr
		}

		addInfos, err := peer.AddrInfosFromP2pAddrs(addrs...)
		if err != nil {
			return err
		}

		node, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}
		if !node.IsOnline {
			return ErrNotOnline
		}

		for _, addrinfo := range addInfos {
			node.Peering.AddPeer(addrinfo)
			err = res.Emit(peeringResult{addrinfo.ID, "success"})
			if err != nil {
				return err
			}
		}
		return nil
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, pr *peeringResult) error {
			fmt.Fprintf(w, "add %s %s\n", pr.ID.String(), pr.Status)
			return nil
		}),
	},
	Type: peeringResult{},
}

var swarmPeeringLsCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "List peers registered in the peering subsystem.",
		ShortDescription: `
'ipfs swarm peering ls' lists the peers that are registered in the peering subsystem and to which the daemon is always connected.
`,
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		node, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}
		if !node.IsOnline {
			return ErrNotOnline
		}

		peers := node.Peering.ListPeers()
		return cmds.EmitOnce(res, addrInfos{Peers: peers})
	},
	Type: addrInfos{},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, ai *addrInfos) error {
			for _, info := range ai.Peers {
				fmt.Fprintf(w, "%s\n", info.ID)
				for _, addr := range info.Addrs {
					fmt.Fprintf(w, "\t%s\n", addr)
				}
			}
			return nil
		}),
	},
}

type addrInfos struct {
	Peers []peer.AddrInfo
}

var swarmPeeringRmCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Remove a peer from the peering subsystem.",
		ShortDescription: `
'ipfs swarm peering rm' will remove the given ID from the peering subsystem and remove it from the always-on connection.
`,
	},
	Arguments: []cmds.Argument{
		cmds.StringArg("ID", true, true, "ID of peer to remove from the peering subsystem"),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		node, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}
		if !node.IsOnline {
			return ErrNotOnline
		}

		for _, arg := range req.Arguments {
			id, err := peer.Decode(arg)
			if err != nil {
				return err
			}

			node.Peering.RemovePeer(id)
			if err = res.Emit(peeringResult{id, "success"}); err != nil {
				return err
			}
		}
		return nil
	},
	Type: peeringResult{},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, pr *peeringResult) error {
			fmt.Fprintf(w, "remove %s %s\n", pr.ID.String(), pr.Status)
			return nil
		}),
	},
}

var swarmPeersCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "List peers with open connections.",
		ShortDescription: `
'ipfs swarm peers' lists the set of peers this node is connected to.
`,
	},
	Options: []cmds.Option{
		cmds.BoolOption(swarmVerboseOptionName, "v", "display all extra information"),
		cmds.BoolOption(swarmStreamsOptionName, "Also list information about open streams for each peer"),
		cmds.BoolOption(swarmLatencyOptionName, "Also list information about latency to each peer"),
		cmds.BoolOption(swarmDirectionOptionName, "Also list information about the direction of connection"),
		cmds.BoolOption(swarmIdentifyOptionName, "Also list information about peers identify"),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		api, err := cmdenv.GetApi(env, req)
		if err != nil {
			return err
		}
		verbose, _ := req.Options[swarmVerboseOptionName].(bool)
		latency, _ := req.Options[swarmLatencyOptionName].(bool)
		streams, _ := req.Options[swarmStreamsOptionName].(bool)
		direction, _ := req.Options[swarmDirectionOptionName].(bool)
		identify, _ := req.Options[swarmIdentifyOptionName].(bool)

		conns, err := api.Swarm().Peers(req.Context)
		if err != nil {
			return err
		}

		var out connInfos
		for _, c := range conns {
			ci := connInfo{
				Addr: c.Address().String(),
				Peer: c.ID().String(),
			}

			if verbose || direction {
				// set direction
				ci.Direction = c.Direction()
			}

			if verbose || latency {
				lat, err := c.Latency()
				if err != nil {
					return err
				}

				if lat == 0 {
					ci.Latency = "n/a"
				} else {
					ci.Latency = lat.String()
				}
			}
			if verbose || streams {
				strs, err := c.Streams()
				if err != nil {
					return err
				}

				for _, s := range strs {
					ci.Streams = append(ci.Streams, streamInfo{Protocol: string(s)})
				}
			}

			if verbose || identify {
				n, err := cmdenv.GetNode(env)
				if err != nil {
					return err
				}
				identifyResult, _ := ci.identifyPeer(n.Peerstore, c.ID())
				ci.Identify = identifyResult
			}
			sort.Sort(&ci)
			out.Peers = append(out.Peers, ci)
		}

		sort.Sort(&out)
		return cmds.EmitOnce(res, &out)
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, ci *connInfos) error {
			pipfs := ma.ProtocolWithCode(ma.P_IPFS).Name
			for _, info := range ci.Peers {
				fmt.Fprintf(w, "%s/%s/%s", info.Addr, pipfs, info.Peer)
				if info.Latency != "" {
					fmt.Fprintf(w, " %s", info.Latency)
				}

				if info.Direction != inet.DirUnknown {
					fmt.Fprintf(w, " %s", directionString(info.Direction))
				}
				fmt.Fprintln(w)

				for _, s := range info.Streams {
					if s.Protocol == "" {
						s.Protocol = "<no protocol name>"
					}

					fmt.Fprintf(w, "  %s\n", s.Protocol)
				}
			}

			return nil
		}),
	},
	Type: connInfos{},
}

var swarmResourcesCmd = &cmds.Command{
	Status: cmds.Experimental,
	Helptext: cmds.HelpText{
		Tagline: "Get a summary of all resources accounted for by the libp2p Resource Manager.",
		LongDescription: `
Get a summary of all resources accounted for by the libp2p Resource Manager.
This includes the limits and the usage against those limits.
This can output a human readable table and JSON encoding.
`,
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		node, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}

		if node.ResourceManager == nil {
			return libp2p.ErrNoResourceMgr
		}

		cfg, err := node.Repo.Config()
		if err != nil {
			return err
		}

		userResourceOverrides, err := node.Repo.UserResourceOverrides()
		if err != nil {
			return err
		}

		// FIXME: we shouldn't recompute limits, either save them or load them from libp2p (https://github.com/libp2p/go-libp2p/issues/2166)
		limitConfig, _, err := libp2p.LimitConfig(cfg.Swarm, userResourceOverrides)
		if err != nil {
			return err
		}

		rapi, ok := node.ResourceManager.(rcmgr.ResourceManagerState)
		if !ok { // NullResourceManager
			return libp2p.ErrNoResourceMgr
		}

		return cmds.EmitOnce(res, libp2p.MergeLimitsAndStatsIntoLimitsConfigAndUsage(limitConfig, rapi.Stat()))
	},
	Encoders: cmds.EncoderMap{
		cmds.JSON: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, limitsAndUsage libp2p.LimitsConfigAndUsage) error {
			return json.NewEncoder(w).Encode(limitsAndUsage)
		}),
		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, limitsAndUsage libp2p.LimitsConfigAndUsage) error {
			tw := tabwriter.NewWriter(w, 20, 8, 0, '\t', 0)
			defer tw.Flush()

			fmt.Fprintf(tw, "%s\t%s\t%s\t%s\t%s\t\n", "Scope", "Limit Name", "Limit Value", "Limit Usage Amount", "Limit Usage Percent")
			for _, ri := range libp2p.LimitConfigsToInfo(limitsAndUsage) {
				var limit, percentage string
				switch ri.LimitValue {
				case rcmgr.Unlimited64:
					limit = "unlimited"
					percentage = "n/a"
				case rcmgr.BlockAllLimit64:
					limit = "blockAll"
					percentage = "n/a"
				default:
					limit = strconv.FormatInt(int64(ri.LimitValue), 10)
					if ri.CurrentUsage == 0 {
						percentage = "0%"
					} else {
						percentage = strconv.FormatFloat(float64(ri.CurrentUsage)/float64(ri.LimitValue)*100, 'f', 1, 64) + "%"
					}
				}
				fmt.Fprintf(tw, "%s\t%s\t%s\t%d\t%s\t\n",
					ri.ScopeName,
					ri.LimitName,
					limit,
					ri.CurrentUsage,
					percentage,
				)
			}

			return nil
		}),
	},
	Type: libp2p.LimitsConfigAndUsage{},
}

type streamInfo struct {
	Protocol string
}

type connInfo struct {
	Addr      string         `json:",omitempty"`
	Peer      string         `json:",omitempty"`
	Latency   string         `json:",omitempty"`
	Muxer     string         `json:",omitempty"`
	Direction inet.Direction `json:",omitempty"`
	Streams   []streamInfo   `json:",omitempty"`
	Identify  IdOutput       `json:",omitempty"`
}

func (ci *connInfo) Less(i, j int) bool {
	return ci.Streams[i].Protocol < ci.Streams[j].Protocol
}

func (ci *connInfo) Len() int {
	return len(ci.Streams)
}

func (ci *connInfo) Swap(i, j int) {
	ci.Streams[i], ci.Streams[j] = ci.Streams[j], ci.Streams[i]
}

type connInfos struct {
	Peers []connInfo
}

func (ci connInfos) Less(i, j int) bool {
	return ci.Peers[i].Addr < ci.Peers[j].Addr
}

func (ci connInfos) Len() int {
	return len(ci.Peers)
}

func (ci connInfos) Swap(i, j int) {
	ci.Peers[i], ci.Peers[j] = ci.Peers[j], ci.Peers[i]
}

func (ci *connInfo) identifyPeer(ps pstore.Peerstore, p peer.ID) (IdOutput, error) {
	var info IdOutput
	info.ID = p.String()

	if pk := ps.PubKey(p); pk != nil {
		pkb, err := ic.MarshalPublicKey(pk)
		if err != nil {
			return IdOutput{}, err
		}
		info.PublicKey = base64.StdEncoding.EncodeToString(pkb)
	}

	addrInfo := ps.PeerInfo(p)
	addrs, err := peer.AddrInfoToP2pAddrs(&addrInfo)
	if err != nil {
		return IdOutput{}, err
	}

	for _, a := range addrs {
		info.Addresses = append(info.Addresses, a.String())
	}
	sort.Strings(info.Addresses)

	if protocols, err := ps.GetProtocols(p); err == nil {
		info.Protocols = append(info.Protocols, protocols...)
		sort.Slice(info.Protocols, func(i, j int) bool { return info.Protocols[i] < info.Protocols[j] })
	}

	if v, err := ps.Get(p, "AgentVersion"); err == nil {
		if vs, ok := v.(string); ok {
			info.AgentVersion = vs
		}
	}

	return info, nil
}

// directionString transfers to string
func directionString(d inet.Direction) string {
	switch d {
	case inet.DirInbound:
		return "inbound"
	case inet.DirOutbound:
		return "outbound"
	default:
		return ""
	}
}

var swarmAddrsCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "List known addresses. Useful for debugging.",
		ShortDescription: `
'ipfs swarm addrs' lists all addresses this node is aware of.
`,
	},
	Subcommands: map[string]*cmds.Command{
		"local":  swarmAddrsLocalCmd,
		"listen": swarmAddrsListenCmd,
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		api, err := cmdenv.GetApi(env, req)
		if err != nil {
			return err
		}

		addrs, err := api.Swarm().KnownAddrs(req.Context)
		if err != nil {
			return err
		}

		out := make(map[string][]string)
		for p, paddrs := range addrs {
			s := p.String()
			for _, a := range paddrs {
				out[s] = append(out[s], a.String())
			}
		}

		return cmds.EmitOnce(res, &addrMap{Addrs: out})
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, am *addrMap) error {
			// sort the ids first
			ids := make([]string, 0, len(am.Addrs))
			for p := range am.Addrs {
				ids = append(ids, p)
			}
			sort.Strings(ids)

			for _, p := range ids {
				paddrs := am.Addrs[p]
				fmt.Fprintf(w, "%s (%d)\n", p, len(paddrs))
				for _, addr := range paddrs {
					fmt.Fprintf(w, "\t%s\n", addr)
				}
			}

			return nil
		}),
	},
	Type: addrMap{},
}

var swarmAddrsLocalCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "List local addresses.",
		ShortDescription: `
'ipfs swarm addrs local' lists all local listening addresses announced to the network.
`,
	},
	Options: []cmds.Option{
		cmds.BoolOption("id", "Show peer ID in addresses."),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		api, err := cmdenv.GetApi(env, req)
		if err != nil {
			return err
		}

		showid, _ := req.Options["id"].(bool)
		self, err := api.Key().Self(req.Context)
		if err != nil {
			return err
		}

		maddrs, err := api.Swarm().LocalAddrs(req.Context)
		if err != nil {
			return err
		}

		var addrs []string
		p2pProtocolName := ma.ProtocolWithCode(ma.P_P2P).Name
		for _, addr := range maddrs {
			saddr := addr.String()
			if showid {
				saddr = path.Join(saddr, p2pProtocolName, self.ID().String())
			}
			addrs = append(addrs, saddr)
		}
		sort.Strings(addrs)
		return cmds.EmitOnce(res, &stringList{addrs})
	},
	Type: stringList{},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(safeTextListEncoder),
	},
}

var swarmAddrsListenCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "List interface listening addresses.",
		ShortDescription: `
'ipfs swarm addrs listen' lists all interface addresses the node is listening on.
`,
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		api, err := cmdenv.GetApi(env, req)
		if err != nil {
			return err
		}

		var addrs []string
		maddrs, err := api.Swarm().ListenAddrs(req.Context)
		if err != nil {
			return err
		}

		for _, addr := range maddrs {
			addrs = append(addrs, addr.String())
		}
		sort.Strings(addrs)

		return cmds.EmitOnce(res, &stringList{addrs})
	},
	Type: stringList{},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(safeTextListEncoder),
	},
}

var swarmConnectCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Open connection to a given peer.",
		ShortDescription: `
'ipfs swarm connect' attempts to ensure a connection to a given peer.

Multiaddresses given are advisory, for example the node may already be aware of other addresses for a given peer or may already have an established connection to the peer.

The address format is a libp2p multiaddr:

ipfs swarm connect /ip4/104.131.131.82/tcp/4001/p2p/QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ
`,
	},
	Arguments: []cmds.Argument{
		cmds.StringArg("address", true, true, "Address of peer to connect to.").EnableStdin(),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		node, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}

		api, err := cmdenv.GetApi(env, req)
		if err != nil {
			return err
		}

		addrs := req.Arguments

		pis, err := parseAddresses(req.Context, addrs, node.DNSResolver)
		if err != nil {
			return err
		}

		output := make([]string, len(pis))
		for i, pi := range pis {
			output[i] = "connect " + pi.ID.String()

			err := api.Swarm().Connect(req.Context, pi)
			if err != nil {
				return fmt.Errorf("%s failure: %s", output[i], err)
			}
			output[i] += " success"
		}

		return cmds.EmitOnce(res, &stringList{output})
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(safeTextListEncoder),
	},
	Type: stringList{},
}

var swarmDisconnectCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Close connection to a given address.",
		ShortDescription: `
'ipfs swarm disconnect' closes a connection to a peer address. The address
format is an IPFS multiaddr:

ipfs swarm disconnect /ip4/104.131.131.82/tcp/4001/p2p/QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ

The disconnect is not permanent; if ipfs needs to talk to that address later,
it will reconnect.
`,
	},
	Arguments: []cmds.Argument{
		cmds.StringArg("address", true, true, "Address of peer to disconnect from.").EnableStdin(),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		node, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}

		api, err := cmdenv.GetApi(env, req)
		if err != nil {
			return err
		}

		addrs, err := parseAddresses(req.Context, req.Arguments, node.DNSResolver)
		if err != nil {
			return err
		}

		output := make([]string, 0, len(addrs))
		for _, ainfo := range addrs {
			maddrs, err := peer.AddrInfoToP2pAddrs(&ainfo)
			if err != nil {
				return err
			}
			// FIXME: This will print:
			//
			//   disconnect QmFoo success
			//   disconnect QmFoo success
			//   ...
			//
			// Once per address specified. However, I'm not sure of
			// a good backwards compat solution. Right now, I'm just
			// preserving the current behavior.
			for _, addr := range maddrs {
				msg := "disconnect " + ainfo.ID.String()
				if err := api.Swarm().Disconnect(req.Context, addr); err != nil {
					msg += " failure: " + err.Error()
				} else {
					msg += " success"
				}
				output = append(output, msg)
			}
		}
		return cmds.EmitOnce(res, &stringList{output})
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(safeTextListEncoder),
	},
	Type: stringList{},
}

// parseAddresses is a function that takes in a slice of string peer addresses
// (multiaddr + peerid) and returns a slice of properly constructed peers
func parseAddresses(ctx context.Context, addrs []string, rslv *madns.Resolver) ([]peer.AddrInfo, error) {
	// resolve addresses
	maddrs, err := resolveAddresses(ctx, addrs, rslv)
	if err != nil {
		return nil, err
	}

	return peer.AddrInfosFromP2pAddrs(maddrs...)
}

// resolveAddresses resolves addresses parallelly
func resolveAddresses(ctx context.Context, addrs []string, rslv *madns.Resolver) ([]ma.Multiaddr, error) {
	ctx, cancel := context.WithTimeout(ctx, dnsResolveTimeout)
	defer cancel()

	var maddrs []ma.Multiaddr
	var wg sync.WaitGroup
	resolveErrC := make(chan error, len(addrs))

	maddrC := make(chan ma.Multiaddr)

	for _, addr := range addrs {
		maddr, err := ma.NewMultiaddr(addr)
		if err != nil {
			return nil, err
		}

		// check whether address ends in `ipfs/Qm...`
		if _, last := ma.SplitLast(maddr); last.Protocol().Code == ma.P_IPFS {
			maddrs = append(maddrs, maddr)
			continue
		}
		wg.Add(1)
		go func(maddr ma.Multiaddr) {
			defer wg.Done()
			raddrs, err := rslv.Resolve(ctx, maddr)
			if err != nil {
				resolveErrC <- err
				return
			}
			// filter out addresses that still doesn't end in `ipfs/Qm...`
			found := 0
			for _, raddr := range raddrs {
				if _, last := ma.SplitLast(raddr); last != nil && last.Protocol().Code == ma.P_IPFS {
					maddrC <- raddr
					found++
				}
			}
			if found == 0 {
				resolveErrC <- fmt.Errorf("found no ipfs peers at %s", maddr)
			}
		}(maddr)
	}
	go func() {
		wg.Wait()
		close(maddrC)
	}()

	for maddr := range maddrC {
		maddrs = append(maddrs, maddr)
	}

	select {
	case err := <-resolveErrC:
		return nil, err
	default:
	}

	return maddrs, nil
}

var swarmFiltersCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Manipulate address filters.",
		ShortDescription: `
'ipfs swarm filters' will list out currently applied filters. Its subcommands
can be used to add or remove said filters. Filters are specified using the
multiaddr-filter format:

Example:

    /ip4/192.168.0.0/ipcidr/16

Where the above is equivalent to the standard CIDR:

    192.168.0.0/16

Filters default to those specified under the "Swarm.AddrFilters" config key.
`,
	},
	Subcommands: map[string]*cmds.Command{
		"add": swarmFiltersAddCmd,
		"rm":  swarmFiltersRmCmd,
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		n, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}

		if !n.IsOnline {
			return ErrNotOnline
		}

		var output []string
		for _, f := range n.Filters.FiltersForAction(ma.ActionDeny) {
			s, err := mamask.ConvertIPNet(&f)
			if err != nil {
				return err
			}
			output = append(output, s)
		}
		return cmds.EmitOnce(res, &stringList{output})
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(safeTextListEncoder),
	},
	Type: stringList{},
}

var swarmFiltersAddCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Add an address filter.",
		ShortDescription: `
'ipfs swarm filters add' will add an address filter to the daemons swarm.
`,
	},
	Arguments: []cmds.Argument{
		cmds.StringArg("address", true, true, "Multiaddr to filter.").EnableStdin(),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		n, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}

		if !n.IsOnline {
			return ErrNotOnline
		}

		if len(req.Arguments) == 0 {
			return errors.New("no filters to add")
		}

		r, err := fsrepo.Open(env.(*commands.Context).ConfigRoot)
		if err != nil {
			return err
		}
		defer r.Close()
		cfg, err := r.Config()
		if err != nil {
			return err
		}

		for _, arg := range req.Arguments {
			mask, err := mamask.NewMask(arg)
			if err != nil {
				return err
			}

			n.Filters.AddFilter(*mask, ma.ActionDeny)
		}

		added, err := filtersAdd(r, cfg, req.Arguments)
		if err != nil {
			return err
		}

		return cmds.EmitOnce(res, &stringList{added})
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(safeTextListEncoder),
	},
	Type: stringList{},
}

var swarmFiltersRmCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Remove an address filter.",
		ShortDescription: `
'ipfs swarm filters rm' will remove an address filter from the daemons swarm.
`,
	},
	Arguments: []cmds.Argument{
		cmds.StringArg("address", true, true, "Multiaddr filter to remove.").EnableStdin(),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		n, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}

		if !n.IsOnline {
			return ErrNotOnline
		}

		r, err := fsrepo.Open(env.(*commands.Context).ConfigRoot)
		if err != nil {
			return err
		}
		defer r.Close()
		cfg, err := r.Config()
		if err != nil {
			return err
		}

		if req.Arguments[0] == "all" || req.Arguments[0] == "*" {
			fs := n.Filters.FiltersForAction(ma.ActionDeny)
			for _, f := range fs {
				n.Filters.RemoveLiteral(f)
			}

			removed, err := filtersRemoveAll(r, cfg)
			if err != nil {
				return err
			}

			return cmds.EmitOnce(res, &stringList{removed})
		}

		for _, arg := range req.Arguments {
			mask, err := mamask.NewMask(arg)
			if err != nil {
				return err
			}

			n.Filters.RemoveLiteral(*mask)
		}

		removed, err := filtersRemove(r, cfg, req.Arguments)
		if err != nil {
			return err
		}

		return cmds.EmitOnce(res, &stringList{removed})
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(safeTextListEncoder),
	},
	Type: stringList{},
}

func filtersAdd(r repo.Repo, cfg *config.Config, filters []string) ([]string, error) {
	addedMap := map[string]struct{}{}
	addedList := make([]string, 0, len(filters))

	// re-add cfg swarm filters to rm dupes
	oldFilters := cfg.Swarm.AddrFilters
	cfg.Swarm.AddrFilters = nil

	// add new filters
	for _, filter := range filters {
		if _, found := addedMap[filter]; found {
			continue
		}

		cfg.Swarm.AddrFilters = append(cfg.Swarm.AddrFilters, filter)
		addedList = append(addedList, filter)
		addedMap[filter] = struct{}{}
	}

	// add back original filters. in this order so that we output them.
	for _, filter := range oldFilters {
		if _, found := addedMap[filter]; found {
			continue
		}

		cfg.Swarm.AddrFilters = append(cfg.Swarm.AddrFilters, filter)
		addedMap[filter] = struct{}{}
	}

	if err := r.SetConfig(cfg); err != nil {
		return nil, err
	}

	return addedList, nil
}

func filtersRemoveAll(r repo.Repo, cfg *config.Config) ([]string, error) {
	removed := cfg.Swarm.AddrFilters
	cfg.Swarm.AddrFilters = nil

	if err := r.SetConfig(cfg); err != nil {
		return nil, err
	}

	return removed, nil
}

func filtersRemove(r repo.Repo, cfg *config.Config, toRemoveFilters []string) ([]string, error) {
	removed := make([]string, 0, len(toRemoveFilters))
	keep := make([]string, 0, len(cfg.Swarm.AddrFilters))

	oldFilters := cfg.Swarm.AddrFilters

	for _, oldFilter := range oldFilters {
		found := false
		for _, toRemoveFilter := range toRemoveFilters {
			if oldFilter == toRemoveFilter {
				found = true
				removed = append(removed, toRemoveFilter)
				break
			}
		}

		if !found {
			keep = append(keep, oldFilter)
		}
	}
	cfg.Swarm.AddrFilters = keep

	if err := r.SetConfig(cfg); err != nil {
		return nil, err
	}

	return removed, nil
}