Add Resolver interface to transport

config/config.go

@@ -150,6 +150,9 @@ func (cfg *Config) makeSwarm() (*swarm.Swarm, error) {
 	if cfg.ResourceManager != nil {
 		opts = append(opts, swarm.WithResourceManager(cfg.ResourceManager))
 	}
+	if cfg.MultiaddrResolver != nil {
+		opts = append(opts, swarm.WithMultiaddrResolver(cfg.MultiaddrResolver))
+	}
 	// TODO: Make the swarm implementation configurable.
 	return swarm.NewSwarm(pid, cfg.Peerstore, opts...)
 }
@@ -218,12 +221,13 @@ func (cfg *Config) NewNode() (host.Host, error) {
 	}
 
 	h, err := bhost.NewHost(swrm, &bhost.HostOpts{
-		ConnManager:         cfg.ConnManager,
-		AddrsFactory:        cfg.AddrsFactory,
-		NATManager:          cfg.NATManager,
-		EnablePing:          !cfg.DisablePing,
-		UserAgent:           cfg.UserAgent,
-		MultiaddrResolver:   cfg.MultiaddrResolver,
+		ConnManager:  cfg.ConnManager,
+		AddrsFactory: cfg.AddrsFactory,
+		NATManager:   cfg.NATManager,
+		EnablePing:   !cfg.DisablePing,
+		UserAgent:    cfg.UserAgent,
+		// TODO
+		// MultiaddrResolver:   cfg.MultiaddrResolver,
 		EnableHolePunching:  cfg.EnableHolePunching,
 		HolePunchingOptions: cfg.HolePunchingOptions,
 		EnableRelayService:  cfg.EnableRelayService,

core/transport/transport.go

@@ -77,6 +77,12 @@ type Transport interface {
 	Proxy() bool
 }
 
+// Resolver can be optionally implemented by transports that want to resolve or transform the
+// multiaddr.
+type Resolver interface {
+	Resolve(ctx context.Context, maddr ma.Multiaddr) ([]ma.Multiaddr, error)
+}
+
 // Listener is an interface closely resembling the net.Listener interface. The
 // only real difference is that Accept() returns Conn's of the type in this
 // package, and also exposes a Multiaddr method as opposed to a regular Addr

p2p/host/basic/basic_host.go

@@ -38,10 +38,6 @@ import (
 	msmux "github.com/multiformats/go-multistream"
 )
 
-// The maximum number of address resolution steps we'll perform for a single
-// peer (for all addresses).
-const maxAddressResolution = 32
-
 // addrChangeTickrInterval is the interval between two address change ticks.
 var addrChangeTickrInterval = 5 * time.Second
 
@@ -701,77 +697,16 @@ func (h *BasicHost) Connect(ctx context.Context, pi peer.AddrInfo) error {
 		}
 	}
 
-	resolved, err := h.resolveAddrs(ctx, h.Peerstore().PeerInfo(pi.ID))
-	if err != nil {
-		return err
-	}
-	h.Peerstore().AddAddrs(pi.ID, resolved, peerstore.TempAddrTTL)
+	// TODO remove this
+	// resolved, err := h.resolveAddrs(ctx, h.Peerstore().PeerInfo(pi.ID))
+	// if err != nil {
+	// 	return err
+	// }
+	// h.Peerstore().AddAddrs(pi.ID, resolved, peerstore.TempAddrTTL)
 
 	return h.dialPeer(ctx, pi.ID)
 }
 
-func (h *BasicHost) resolveAddrs(ctx context.Context, pi peer.AddrInfo) ([]ma.Multiaddr, error) {
-	proto := ma.ProtocolWithCode(ma.P_P2P).Name
-	p2paddr, err := ma.NewMultiaddr("/" + proto + "/" + pi.ID.Pretty())
-	if err != nil {
-		return nil, err
-	}
-
-	resolveSteps := 0
-
-	// Recursively resolve all addrs.
-	//
-	// While the toResolve list is non-empty:
-	// * Pop an address off.
-	// * If the address is fully resolved, add it to the resolved list.
-	// * Otherwise, resolve it and add the results to the "to resolve" list.
-	toResolve := append(([]ma.Multiaddr)(nil), pi.Addrs...)
-	resolved := make([]ma.Multiaddr, 0, len(pi.Addrs))
-	for len(toResolve) > 0 {
-		// pop the last addr off.
-		addr := toResolve[len(toResolve)-1]
-		toResolve = toResolve[:len(toResolve)-1]
-
-		// if it's resolved, add it to the resolved list.
-		if !madns.Matches(addr) {
-			resolved = append(resolved, addr)
-			continue
-		}
-
-		resolveSteps++
-
-		// We've resolved too many addresses. We can keep all the fully
-		// resolved addresses but we'll need to skip the rest.
-		if resolveSteps >= maxAddressResolution {
-			log.Warnf(
-				"peer %s asked us to resolve too many addresses: %s/%s",
-				pi.ID,
-				resolveSteps,
-				maxAddressResolution,
-			)
-			continue
-		}
-
-		// otherwise, resolve it
-		reqaddr := addr.Encapsulate(p2paddr)
-		resaddrs, err := h.maResolver.Resolve(ctx, reqaddr)
-		if err != nil {
-			log.Infof("error resolving %s: %s", reqaddr, err)
-		}
-
-		// add the results to the toResolve list.
-		for _, res := range resaddrs {
-			pi, err := peer.AddrInfoFromP2pAddr(res)
-			if err != nil {
-				log.Infof("error parsing %s: %s", res, err)
-			}
-			toResolve = append(toResolve, pi.Addrs...)
-		}
-	}
-
-	return resolved, nil
-}
-
 // dialPeer opens a connection to peer, and makes sure to identify
 // the connection once it has been opened.
 func (h *BasicHost) dialPeer(ctx context.Context, p peer.ID) error {

p2p/net/swarm/dial_test.go

@@ -11,12 +11,14 @@ import (
 	"github.com/libp2p/go-libp2p/core/peer"
 	"github.com/libp2p/go-libp2p/core/peerstore"
 	testutil "github.com/libp2p/go-libp2p/core/test"
+	"github.com/libp2p/go-libp2p/p2p/net/swarm"
 	. "github.com/libp2p/go-libp2p/p2p/net/swarm"
 	swarmt "github.com/libp2p/go-libp2p/p2p/net/swarm/testing"
 
 	"github.com/libp2p/go-libp2p-testing/ci"
 
 	ma "github.com/multiformats/go-multiaddr"
+	madns "github.com/multiformats/go-multiaddr-dns"
 	manet "github.com/multiformats/go-multiaddr/net"
 	"github.com/stretchr/testify/require"
 )
@@ -45,6 +47,44 @@ func TestBasicDialPeer(t *testing.T) {
 	s.Close()
 }
 
+func TestBasicDialPeerWithResolver(t *testing.T) {
+	t.Parallel()
+
+	mockResolver := madns.MockResolver{IP: make(map[string][]net.IPAddr)}
+	ipaddr, err := net.ResolveIPAddr("ip4", "127.0.0.1")
+	require.NoError(t, err)
+	mockResolver.IP["example.com"] = []net.IPAddr{*ipaddr}
+	resolver, err := madns.NewResolver(madns.WithDomainResolver("example.com", &mockResolver))
+	require.NoError(t, err)
+
+	swarms := makeSwarms(t, 2, swarmt.WithSwarmOpts([]swarm.Option{swarm.WithMultiaddrResolver(resolver)}))
+	defer closeSwarms(swarms)
+	s1 := swarms[0]
+	s2 := swarms[1]
+
+	// Change the multiaddr from /ip4/127.0.0.1/... to /dns4/example.com/... so
+	// that the resovler has to resolve this
+	var s2Addrs []ma.Multiaddr
+	for _, a := range s2.ListenAddresses() {
+		_, rest := ma.SplitFunc(a, func(c ma.Component) bool {
+			return c.Protocol().Code == ma.P_TCP || c.Protocol().Code == ma.P_UDP
+		},
+		)
+		if rest != nil {
+			s2Addrs = append(s2Addrs, ma.StringCast("/dns4/example.com").Encapsulate(rest))
+		}
+	}
+
+	s1.Peerstore().AddAddrs(s2.LocalPeer(), s2Addrs, peerstore.PermanentAddrTTL)
+
+	c, err := s1.DialPeer(context.Background(), s2.LocalPeer())
+	require.NoError(t, err)
+
+	s, err := c.NewStream(context.Background())
+	require.NoError(t, err)
+	s.Close()
+}
+
 func TestDialWithNoListeners(t *testing.T) {
 	t.Parallel()
 

p2p/net/swarm/swarm.go

@@ -19,6 +19,7 @@ import (
 
 	logging "github.com/ipfs/go-log/v2"
 	ma "github.com/multiformats/go-multiaddr"
+	madns "github.com/multiformats/go-multiaddr-dns"
 )
 
 const (
@@ -54,6 +55,14 @@ func WithConnectionGater(gater connmgr.ConnectionGater) Option {
 	}
 }
 
+// WithMultiaddrResolver sets a custom multiaddr.Resolver
+func WithMultiaddrResolver(maResolver *madns.Resolver) Option {
+	return func(s *Swarm) error {
+		s.maResolver = maResolver
+		return nil
+	}
+}
+
 // WithMetrics sets a metrics reporter
 func WithMetrics(reporter metrics.Reporter) Option {
 	return func(s *Swarm) error {
@@ -127,6 +136,8 @@ type Swarm struct {
 		m map[int]transport.Transport
 	}
 
+	maResolver *madns.Resolver
+
 	// stream handlers
 	streamh atomic.Value
 
@@ -153,6 +164,7 @@ func NewSwarm(local peer.ID, peers peerstore.Peerstore, opts ...Option) (*Swarm,
 		ctxCancel:        cancel,
 		dialTimeout:      defaultDialTimeout,
 		dialTimeoutLocal: defaultDialTimeoutLocal,
+		maResolver:       madns.DefaultResolver,
 	}
 
 	s.conns.m = make(map[peer.ID][]*Conn)

p2p/net/swarm/swarm_dial.go

@@ -13,9 +13,14 @@ import (
 	"github.com/libp2p/go-libp2p/core/transport"
 
 	ma "github.com/multiformats/go-multiaddr"
+	madns "github.com/multiformats/go-multiaddr-dns"
 	manet "github.com/multiformats/go-multiaddr/net"
 )
 
+// The maximum number of address resolution steps we'll perform for a single
+// peer (for all addresses).
+const maxAddressResolution = 32
+
 // Diagram of dial sync:
 //
 //   many callers of Dial()   synched w.  dials many addrs       results to callers
@@ -292,7 +297,32 @@ func (s *Swarm) addrsForDial(ctx context.Context, p peer.ID) ([]ma.Multiaddr, er
 		return nil, ErrNoAddresses
 	}
 
-	goodAddrs := s.filterKnownUndialables(p, peerAddrs)
+	peerAddrsAfterTransportResolved := make([]ma.Multiaddr, 0, len(peerAddrs))
+	for _, a := range peerAddrs {
+		tpt := s.TransportForDialing(a)
+		resolver, ok := tpt.(transport.Resolver)
+		if ok {
+			resolvedAddrs, err := resolver.Resolve(ctx, a)
+			if err != nil {
+				log.Warnf("Failed to resolve multiaddr %s by transport %v: %v", a, tpt, err)
+				continue
+			}
+			peerAddrsAfterTransportResolved = append(peerAddrsAfterTransportResolved, resolvedAddrs...)
+		} else {
+			peerAddrsAfterTransportResolved = append(peerAddrsAfterTransportResolved, a)
+		}
+	}
+
+	// Resolve dns or dnsaddrs
+	resolved, err := s.resolveAddrs(ctx, peer.AddrInfo{
+		ID:    p,
+		Addrs: peerAddrsAfterTransportResolved,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	goodAddrs := s.filterKnownUndialables(p, resolved)
 	if forceDirect, _ := network.GetForceDirectDial(ctx); forceDirect {
 		goodAddrs = ma.FilterAddrs(goodAddrs, s.nonProxyAddr)
 	}
@@ -301,7 +331,72 @@ func (s *Swarm) addrsForDial(ctx context.Context, p peer.ID) ([]ma.Multiaddr, er
 		return nil, ErrNoGoodAddresses
 	}
 
-	return goodAddrs, nil
+	// Do we store the addrs?
+	// h.Peerstore().AddAddrs(pi.ID, goodAddrs, peerstore.TempAddrTTL)
+
+	return resolved, nil
+}
+
+func (s *Swarm) resolveAddrs(ctx context.Context, pi peer.AddrInfo) ([]ma.Multiaddr, error) {
+	proto := ma.ProtocolWithCode(ma.P_P2P).Name
+	p2paddr, err := ma.NewMultiaddr("/" + proto + "/" + pi.ID.Pretty())
+	if err != nil {
+		return nil, err
+	}
+
+	resolveSteps := 0
+
+	// Recursively resolve all addrs.
+	//
+	// While the toResolve list is non-empty:
+	// * Pop an address off.
+	// * If the address is fully resolved, add it to the resolved list.
+	// * Otherwise, resolve it and add the results to the "to resolve" list.
+	toResolve := append(([]ma.Multiaddr)(nil), pi.Addrs...)
+	resolved := make([]ma.Multiaddr, 0, len(pi.Addrs))
+	for len(toResolve) > 0 {
+		// pop the last addr off.
+		addr := toResolve[len(toResolve)-1]
+		toResolve = toResolve[:len(toResolve)-1]
+
+		// if it's resolved, add it to the resolved list.
+		if !madns.Matches(addr) {
+			resolved = append(resolved, addr)
+			continue
+		}
+
+		resolveSteps++
+
+		// We've resolved too many addresses. We can keep all the fully
+		// resolved addresses but we'll need to skip the rest.
+		if resolveSteps >= maxAddressResolution {
+			log.Warnf(
+				"peer %s asked us to resolve too many addresses: %s/%s",
+				pi.ID,
+				resolveSteps,
+				maxAddressResolution,
+			)
+			continue
+		}
+
+		// otherwise, resolve it
+		reqaddr := addr.Encapsulate(p2paddr)
+		resaddrs, err := s.maResolver.Resolve(ctx, reqaddr)
+		if err != nil {
+			log.Infof("error resolving %s: %s", reqaddr, err)
+		}
+
+		// add the results to the toResolve list.
+		for _, res := range resaddrs {
+			pi, err := peer.AddrInfoFromP2pAddr(res)
+			if err != nil {
+				log.Infof("error parsing %s: %s", res, err)
+			}
+			toResolve = append(toResolve, pi.Addrs...)
+		}
+	}
+
+	return resolved, nil
 }
 
 func (s *Swarm) dialNextAddr(ctx context.Context, p peer.ID, addr ma.Multiaddr, resch chan dialResult) error {