p2p: external address

* new config option for external address to advertise
* if blank, defaults to best guess from listener
* if laddr ip address is also blank, default to IPv4

CHANGELOG.md

@@ -22,6 +22,8 @@ FEATURES
   [metrics](https://tendermint.readthedocs.io/projects/tools/en/develop/metrics.html)
   guide.
 - [p2p] Add IPv6 support to peering.
+- [p2p] Add `external_address` to config to allow specifying the address for
+  peers to dial
 
 IMPROVEMENT
 - [rpc/client] Supports https and wss now.

config/config.go

@@ -276,6 +276,9 @@ type P2PConfig struct {
 	// Address to listen for incoming connections
 	ListenAddress string `mapstructure:"laddr"`
 
+	// Address to advertise to peers for them to dial
+	ExternalAddress string `mapstructure:"external_address"`
+
 	// Comma separated list of seed nodes to connect to
 	// We only use these if we can’t connect to peers in the addrbook
 	Seeds string `mapstructure:"seeds"`
@@ -340,6 +343,7 @@ type P2PConfig struct {
 func DefaultP2PConfig() *P2PConfig {
 	return &P2PConfig{
 		ListenAddress:           "tcp://0.0.0.0:26656",
+		ExternalAddress:         "",
 		UPNP:                    false,
 		AddrBook:                defaultAddrBookPath,
 		AddrBookStrict:          true,

config/toml.go

@@ -142,6 +142,12 @@ max_open_connections = {{ .RPC.MaxOpenConnections }}
 # Address to listen for incoming connections
 laddr = "{{ .P2P.ListenAddress }}"
 
+# Address to advertise to peers for them to dial
+# If empty, will use the same port as the laddr,
+# and will introspect on the listener or use UPnP
+# to figure out the address.
+external_address = "{{ .P2P.ExternalAddress }}"
+
 # Comma separated list of seed nodes to connect to
 seeds = "{{ .P2P.Seeds }}"
 

node/node.go

@@ -426,8 +426,7 @@ func (n *Node) OnStart() error {
 	}
 
 	// Create & add listener
-	protocol, address := cmn.ProtocolAndAddress(n.config.P2P.ListenAddress)
-	l := p2p.NewDefaultListener(protocol, address, n.config.P2P.UPNP, n.Logger.With("module", "p2p"))
+	l := p2p.NewDefaultListener(n.config.P2P, n.Logger.With("module", "p2p"))
 	n.sw.AddListener(l)
 
 	// Generate node PrivKey

p2p/listener.go

@@ -7,9 +7,10 @@ import (
 	"strings"
 	"time"
 
-	"github.com/tendermint/tendermint/p2p/upnp"
+	"github.com/tendermint/tendermint/config"
 	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	"github.com/tendermint/tendermint/p2p/upnp"
 )
 
 // Listener is a network listener for stream-oriented protocols, providing
@@ -59,8 +60,10 @@ func splitHostPort(addr string) (host string, port int) {
 
 // NewDefaultListener creates a new DefaultListener on lAddr, optionally trying
 // to determine external address using UPnP.
-func NewDefaultListener(protocol string, lAddr string, UPNP bool, logger log.Logger) Listener {
-	// Local listen IP & port
+func NewDefaultListener(cfg *config.P2PConfig, logger log.Logger) Listener {
+
+	// Split protocol, address, and port.
+	protocol, lAddr := cmn.ProtocolAndAddress(cfg.ListenAddress)
 	lAddrIP, lAddrPort := splitHostPort(lAddr)
 
 	// Create listener
@@ -88,17 +91,29 @@ func NewDefaultListener(protocol string, lAddr string, UPNP bool, logger log.Log
 		panic(err)
 	}
 
+	inAddrAny := lAddrIP == "" || lAddrIP == "0.0.0.0"
+
 	// Determine external address...
 	var extAddr *NetAddress
-	if UPNP {
+	if cfg.UPNP {
 		// If the lAddrIP is INADDR_ANY, try UPnP
-		if lAddrIP == "" || lAddrIP == "0.0.0.0" {
+		if inAddrAny {
 			extAddr = getUPNPExternalAddress(lAddrPort, listenerPort, logger)
 		}
 	}
+
+	if cfg.ExternalAddress != "" {
+		var err error
+		extAddr, err = NewNetAddressStringWithOptionalID(cfg.ExternalAddress)
+		if err != nil {
+			panic(fmt.Sprintf("Error in ExternalAddress: %v", err))
+		}
+	}
+
 	// Otherwise just use the local address...
 	if extAddr == nil {
-		extAddr = getNaiveExternalAddress(listenerPort, false, logger)
+		defaultToIPv4 := inAddrAny
+		extAddr = getNaiveExternalAddress(defaultToIPv4, listenerPort, false, logger)
 	}
 	if extAddr == nil {
 		panic("Could not determine external address!")
@@ -237,7 +252,7 @@ func isIpv6(ip net.IP) bool {
 }
 
 // TODO: use syscalls: see issue #712
-func getNaiveExternalAddress(port int, settleForLocal bool, logger log.Logger) *NetAddress {
+func getNaiveExternalAddress(defaultToIPv4 bool, port int, settleForLocal bool, logger log.Logger) *NetAddress {
 	addrs, err := net.InterfaceAddrs()
 	if err != nil {
 		panic(cmn.Fmt("Could not fetch interface addresses: %v", err))
@@ -248,7 +263,7 @@ func getNaiveExternalAddress(port int, settleForLocal bool, logger log.Logger) *
 		if !ok {
 			continue
 		}
-		if !isIpv6(ipnet.IP) {
+		if defaultToIPv4 || !isIpv6(ipnet.IP) {
 			v4 := ipnet.IP.To4()
 			if v4 == nil || (!settleForLocal && v4[0] == 127) {
 				// loopback
@@ -263,5 +278,5 @@ func getNaiveExternalAddress(port int, settleForLocal bool, logger log.Logger) *
 
 	// try again, but settle for local
 	logger.Info("Node may not be connected to internet. Settling for local address")
-	return getNaiveExternalAddress(port, true, logger)
+	return getNaiveExternalAddress(defaultToIPv4, port, true, logger)
 }

p2p/listener_test.go

@@ -4,12 +4,16 @@ import (
 	"bytes"
 	"testing"
 
+	"github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/libs/log"
 )
 
 func TestListener(t *testing.T) {
 	// Create a listener
-	l := NewDefaultListener("tcp", ":8001", false, log.TestingLogger())
+	cfg := &config.P2PConfig{
+		ListenAddress: "tcp://:8001",
+	}
+	l := NewDefaultListener(cfg, log.TestingLogger())
 
 	// Dial the listener
 	lAddr := l.ExternalAddress()

p2p/pex/pex_reactor_test.go

@@ -109,7 +109,10 @@ func TestPEXReactorRunning(t *testing.T) {
 	addOtherNodeAddrToAddrBook(2, 1)
 
 	for i, sw := range switches {
-		sw.AddListener(p2p.NewDefaultListener("tcp", sw.NodeInfo().ListenAddr, false, logger.With("pex", i)))
+		cfg := &config.P2PConfig{
+			ListenAddress: fmt.Sprintf("tcp://%v", sw.NodeInfo().ListenAddr),
+		}
+		sw.AddListener(p2p.NewDefaultListener(cfg, logger.With("pex", i)))
 
 		err := sw.Start() // start switch and reactors
 		require.Nil(t, err)
@@ -230,9 +233,9 @@ func TestPEXReactorUsesSeedsIfNeeded(t *testing.T) {
 	)
 	seed.AddListener(
 		p2p.NewDefaultListener(
-			"tcp",
-			seed.NodeInfo().ListenAddr,
-			false,
+			&config.P2PConfig{
+				ListenAddress: fmt.Sprintf("tcp://%v", seed.NodeInfo().ListenAddr),
+			},
 			log.TestingLogger(),
 		),
 	)