Listen to all Network Interfaces for discovery

beacon-chain/p2p/discovery.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"crypto/ecdsa"
 	"net"
-	"strconv"
 	"time"
 
 	"github.com/ethereum/go-ethereum/p2p/discover"
@@ -98,16 +97,17 @@ func (s *Service) createListener(
 	ipAddr net.IP,
 	privKey *ecdsa.PrivateKey,
 ) (*discover.UDPv5, error) {
-	// assume ip is either ipv4 or ipv6
+	// Listen to all network interfaces
+	// for both ip protocols.
 	networkVersion := ""
 	if ipAddr.To4() != nil {
 		networkVersion = "udp4"
+		ipAddr = net.IPv4zero
 	} else {
 		networkVersion = "udp6"
+		ipAddr = net.IPv6zero
 	}
-	// Check for the real local address which may
-	// be different in the presence of virtual networks.
-	ipAddr = s.localAddress(networkVersion, ipAddr)
+
 	// If local ip is specified then use that instead.
 	if s.cfg.LocalIP != "" {
 		ipAddr = net.ParseIP(s.cfg.LocalIP)
@@ -185,6 +185,17 @@ func (s *Service) createLocalNode(
 		return nil, errors.Wrap(err, "could not open node's peer database")
 	}
 	localNode := enode.NewLocalNode(db, privKey)
+	// In the event we have a zero ip passed in, we
+	// instead persist the loopback ip in the
+	// localnode entry.
+	switch {
+	case ipAddr.Equal(net.IPv4zero):
+		ipAddr = net.ParseIP("127.0.0.1")
+	case ipAddr.Equal(net.IPv6zero):
+		ipAddr = net.IPv6loopback
+	default:
+		// do nothing
+	}
 	ipEntry := enr.IP(ipAddr)
 	udpEntry := enr.UDP(udpPort)
 	tcpEntry := enr.TCP(tcpPort)
@@ -275,37 +286,6 @@ func (s *Service) isPeerAtLimit() bool {
 	return activePeers >= maxPeers || numOfConns >= maxPeers
 }
 
-// retrieve real local address of the node. In the event
-// that is not possible we return the provided ip.
-func (s *Service) localAddress(network string, addr net.IP) net.IP {
-	if len(s.cfg.BootstrapNodeAddr) == 0 {
-		return addr
-	}
-	// Dial the first bootnode to determine our 'real' local address.
-	bootNode, err := enode.Parse(enode.ValidSchemes, s.cfg.BootstrapNodeAddr[0])
-	if err != nil {
-		log.Error("Could not parse bootnode address")
-		return addr
-	}
-	conn, err := net.DialTimeout(network, net.JoinHostPort(bootNode.IP().String(), strconv.Itoa(bootNode.UDP())), dialTimeout)
-	if err != nil {
-		log.Error("Could not dial remote peer")
-		return addr
-	}
-	defer func() {
-		if err := conn.Close(); err != nil {
-			log.Error(err)
-		}
-	}()
-	// Determine the real address from which the initial connection was made.
-	realAddr, _, err := net.SplitHostPort(conn.LocalAddr().String())
-	if err != nil {
-		log.Error("Could not dial remote peer")
-		return addr
-	}
-	return net.ParseIP(realAddr)
-}
-
 func parseBootStrapAddrs(addrs []string) (discv5Nodes []string) {
 	discv5Nodes, _ = parseGenericAddrs(addrs)
 	if len(discv5Nodes) == 0 {