Support different hosts for each network

CircleCI's localhost hostname doesn't resolve for IPv6.

client.go

@@ -225,7 +225,7 @@ func NewClient(cfg *Config) (cl *Client, err error) {
 		}
 	}
 
-	cl.conns, err = listenAll(cl.enabledPeerNetworks(), cl.config.ListenAddr)
+	cl.conns, err = listenAll(cl.enabledPeerNetworks(), cl.config.ListenHost, cl.config.ListenPort)
 	if err != nil {
 		return
 	}

client_test.go

@@ -9,6 +9,7 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -31,7 +32,13 @@ import (
 
 func TestingConfig() *Config {
 	return &Config{
-		ListenAddr:              "localhost:0",
+		ListenHost: func(network string) string {
+			if strings.Contains(network, "4") {
+				return "127.0.0.1"
+			} else {
+				return "::1"
+			}
+		},
 		NoDHT:                   true,
 		DataDir:                 tempDir(),
 		DisableTrackers:         true,
@@ -540,7 +547,7 @@ func BenchmarkAddLargeTorrent(b *testing.B) {
 	cfg := TestingConfig()
 	cfg.DisableTCP = true
 	cfg.DisableUTP = true
-	cfg.ListenAddr = "redonk"
+	cfg.ListenHost = func(string) string { return "redonk" }
 	cl, err := NewClient(cfg)
 	require.NoError(b, err)
 	defer cl.Close()
@@ -756,7 +763,7 @@ func TestAddTorrentPiecesNotAlreadyCompleted(t *testing.T) {
 
 func TestAddMetainfoWithNodes(t *testing.T) {
 	cfg := TestingConfig()
-	cfg.ListenAddr = ":0"
+	cfg.ListenHost = func(string) string { return "" }
 	cfg.NoDHT = false
 	cfg.DhtStartingNodes = func() ([]dht.Addr, error) { return nil, nil }
 	// For now, we want to just jam the nodes into the table, without
@@ -1065,8 +1072,7 @@ func TestClientAddressInUse(t *testing.T) {
 	if s != nil {
 		defer s.Close()
 	}
-	cfg := TestingConfig()
-	cfg.ListenAddr = ":50007"
+	cfg := TestingConfig().SetListenAddr(":50007")
 	cl, err := NewClient(cfg)
 	require.Error(t, err)
 	require.Nil(t, cl)

cmd/torrent/main.go

@@ -162,7 +162,7 @@ func main() {
 		clientConfig.DefaultStorage = storage.NewMMap("")
 	}
 	if flags.Addr != nil {
-		clientConfig.ListenAddr = flags.Addr.String()
+		clientConfig.SetListenAddr(flags.Addr.String())
 	}
 	if flags.UploadRate != -1 {
 		clientConfig.UploadRateLimiter = rate.NewLimiter(rate.Limit(flags.UploadRate), 256<<10)

cmd/torrentfs/main.go

@@ -86,12 +86,13 @@ func mainExitCode() int {
 	defer fuse.Unmount(args.MountDir)
 	// TODO: Think about the ramifications of exiting not due to a signal.
 	defer conn.Close()
-	client, err := torrent.NewClient(&torrent.Config{
+	cfg := torrent.Config{
 		DataDir:         args.DownloadDir,
 		DisableTrackers: args.DisableTrackers,
-		ListenAddr:      args.ListenAddr.String(),
 		NoUpload:        true, // Ensure that downloads are responsive.
-	})
+	}
+	cfg.SetListenAddr(args.ListenAddr.String())
+	client, err := torrent.NewClient(&cfg)
 	if err != nil {
 		log.Print(err)
 		return 1

config.go

@@ -9,6 +9,8 @@ import (
 	"golang.org/x/time/rate"
 
 	"github.com/anacrolix/dht"
+	"github.com/anacrolix/missinggo"
+	"github.com/anacrolix/missinggo/expect"
 	"github.com/anacrolix/torrent/iplist"
 	"github.com/anacrolix/torrent/storage"
 )
@@ -33,7 +35,8 @@ type Config struct {
 	// The address to listen for new uTP and TCP bittorrent protocol
 	// connections. DHT shares a UDP socket with uTP unless configured
 	// otherwise.
-	ListenAddr              string `long:"listen-addr" value-name:"HOST:PORT"`
+	ListenHost              func(network string) string
+	ListenPort              int
 	NoDefaultPortForwarding bool
 	// Don't announce to trackers. This only leaves DHT to discover peers.
 	DisableTrackers bool `long:"disable-trackers"`
@@ -112,6 +115,14 @@ type Config struct {
 	PublicIp6 net.IP
 }
 
+func (cfg *Config) SetListenAddr(addr string) *Config {
+	host, port, err := missinggo.ParseHostPort(addr)
+	expect.Nil(err)
+	cfg.ListenHost = func(string) string { return host }
+	cfg.ListenPort = port
+	return cfg
+}
+
 func (cfg *Config) setDefaults() {
 	if cfg.HTTP == nil {
 		cfg.HTTP = DefaultHTTPClient

fs/torrentfs_test.go

@@ -165,13 +165,12 @@ func TestDownloadOnDemand(t *testing.T) {
 	layout, err := newGreetingLayout()
 	require.NoError(t, err)
 	defer layout.Destroy()
-	seeder, err := torrent.NewClient(&torrent.Config{
+	seeder, err := torrent.NewClient((&torrent.Config{
 		DataDir:         layout.Completed,
 		DisableTrackers: true,
 		NoDHT:           true,
-		ListenAddr:      "localhost:0",
 		Seed:            true,
-	})
+	}).SetListenAddr("localhost:0"))
 	require.NoError(t, err)
 	defer seeder.Close()
 	testutil.ExportStatusWriter(seeder, "s")
@@ -184,16 +183,15 @@ func TestDownloadOnDemand(t *testing.T) {
 		<-seederTorrent.GotInfo()
 		seederTorrent.VerifyData()
 	}()
-	leecher, err := torrent.NewClient(&torrent.Config{
+	leecher, err := torrent.NewClient((&torrent.Config{
 		DisableTrackers: true,
 		NoDHT:           true,
-		ListenAddr:      "localhost:0",
 		DisableTCP:      true,
 		DefaultStorage:  storage.NewMMap(filepath.Join(layout.BaseDir, "download")),
 		// This can be used to check if clients can connect to other clients
 		// with the same ID.
 		// PeerID: seeder.PeerID(),
-	})
+	}).SetListenAddr("localhost:0"))
 	require.NoError(t, err)
 	testutil.ExportStatusWriter(leecher, "l")
 	defer leecher.Close()

socket.go

@@ -61,26 +61,31 @@ func setPort(addr string, port int) string {
 	return net.JoinHostPort(host, strconv.FormatInt(int64(port), 10))
 }
 
-func listenAll(networks []string, addr string) ([]socket, error) {
+func listenAll(networks []string, getHost func(string) string, port int) ([]socket, error) {
 	if len(networks) == 0 {
 		return nil, nil
 	}
+	var nahs []networkAndHost
+	for _, n := range networks {
+		nahs = append(nahs, networkAndHost{n, getHost(n)})
+	}
 	for {
-		ss, retry, err := listenAllRetry(networks, addr)
+		ss, retry, err := listenAllRetry(nahs, port)
 		if !retry {
 			return ss, err
 		}
 	}
 }
 
-func listenAllRetry(networks []string, addr string) (ss []socket, retry bool, err error) {
-	_, port, err := missinggo.ParseHostPort(addr)
-	if err != nil {
-		err = fmt.Errorf("error parsing addr: %s", err)
-		return
-	}
-	ss = make([]socket, 1, len(networks))
-	ss[0], err = listen(networks[0], addr)
+type networkAndHost struct {
+	Network string
+	Host    string
+}
+
+func listenAllRetry(nahs []networkAndHost, port int) (ss []socket, retry bool, err error) {
+	ss = make([]socket, 1, len(nahs))
+	portStr := strconv.FormatInt(int64(port), 10)
+	ss[0], err = listen(nahs[0].Network, net.JoinHostPort(nahs[0].Host, portStr))
 	if err != nil {
 		return nil, false, fmt.Errorf("first listen: %s", err)
 	}
@@ -92,9 +97,9 @@ func listenAllRetry(networks []string, addr string) (ss []socket, retry bool, er
 			ss = nil
 		}
 	}()
-	restAddr := setPort(addr, missinggo.AddrPort(ss[0].Addr()))
-	for _, n := range networks[1:] {
-		s, err := listen(n, restAddr)
+	portStr = strconv.FormatInt(int64(missinggo.AddrPort(ss[0].Addr())), 10)
+	for _, nah := range nahs[1:] {
+		s, err := listen(nah.Network, net.JoinHostPort(nah.Host, portStr))
 		if err != nil {
 			return ss,
 				missinggo.IsAddrInUse(err) && port == 0,