changes based on comments

server/federation.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"log"
 	"math"
+	"net"
 	"os"
 	"strings"
 	"sync/atomic"
@@ -27,6 +28,7 @@ var (
 		"127.0.0.1": true,
 		"0.0.0.0": true,
 		"localhost": true,
+		"<nil>": true,
 	}
 )
 
@@ -70,6 +72,7 @@ func (s *Server) getNumSubs() int64 {
 // getAndSetExternalIp takes the address of a peer running a UDP server and
 // pings it, so we can determine our own external IP address.
 func (s *Server) getAndSetExternalIp(msg *pb.ServerMessage) error {
+	log.Println(msg)
 	myIp, err := UDPPing(msg.Address, msg.Port)
 	if err != nil {
 		return err
@@ -139,7 +142,7 @@ retry:
 		// If the peer is us, skip
 		log.Println(ipPort)
 		if ipPort[1] == port &&
-			(localHosts[ipPort[0]] || ipPort[0] == s.ExternalIP) {
+			(localHosts[ipPort[0]] || ipPort[0] == s.ExternalIP.String()) {
 			log.Println("Self peer, skipping ...")
 			continue
 		}
@@ -177,7 +180,7 @@ func (s *Server) subscribeToPeer(peer *FederatedServer) error {
 	defer conn.Close()
 
 	msg := &pb.ServerMessage{
-		Address: s.ExternalIP,
+		Address: s.ExternalIP.String(),
 		Port:    s.Args.Port,
 	}
 
@@ -217,7 +220,7 @@ func (s *Server) helloPeer(server *FederatedServer) (*pb.HelloMessage, error) {
 
 	msg := &pb.HelloMessage{
 		Port: s.Args.Port,
-		Host: s.ExternalIP,
+		Host: s.ExternalIP.String(),
 		Servers: []*pb.ServerMessage{},
 	}
 
@@ -327,7 +330,10 @@ func (s *Server) notifyPeerSubs(newServer *FederatedServer) {
 func (s *Server) addPeer(msg *pb.ServerMessage, ping bool, subscribe bool) error {
 	// First thing we get our external ip if we don't have it, otherwise we
 	// could end up subscribed to our self, which is silly.
-	if s.ExternalIP == "" {
+	nilIP := net.IP{}
+	//localIP0 := net.IPv4(0,0,0,0)
+	localIP1 := net.IPv4(127,0,0,1)
+	if s.ExternalIP.Equal(nilIP) || s.ExternalIP.Equal(localIP1) {
 		err := s.getAndSetExternalIp(msg)
 		if err != nil {
 			log.Println(err)
@@ -336,7 +342,7 @@ func (s *Server) addPeer(msg *pb.ServerMessage, ping bool, subscribe bool) error
 	}
 
 	if s.Args.Port == msg.Port &&
-		(localHosts[msg.Address] || msg.Address == s.ExternalIP) {
+		(localHosts[msg.Address] || msg.Address == s.ExternalIP.String()) {
 		log.Printf("%s:%s addPeer: Self peer, skipping...\n", s.ExternalIP, s.Args.Port)
 		return nil
 	}
@@ -406,7 +412,7 @@ func (s *Server) makeHelloMessage() *pb.HelloMessage {
 
 	return &pb.HelloMessage{
 		Port: s.Args.Port,
-		Host: s.ExternalIP,
+		Host: s.ExternalIP.String(),
 		Servers: servers,
 	}
 }

server/federation_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"net"
 	"os"
 	"strings"
 	"testing"
@@ -88,7 +89,7 @@ func TestAddPeer(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T){
 			server := MakeHubServer(ctx, args)
-			server.ExternalIP = "0.0.0.0"
+			server.ExternalIP = net.IPv4(0,0,0,0)
 			metrics.PeersKnown.Set(0)
 
 			for i := 0; i < 10; i++ {
@@ -147,7 +148,7 @@ func TestPeerWriter(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T){
 			server := MakeHubServer(ctx, args)
-			server.ExternalIP = "0.0.0.0"
+			server.ExternalIP = net.IPv4(0,0,0,0)
 
 			for i := 0; i < 10; i++ {
 				var msg *pb.ServerMessage
@@ -466,12 +467,12 @@ func TestUDPServer(t *testing.T) {
 			server.GrpcServer.GracefulStop()
 			server2.GrpcServer.GracefulStop()
 
-			got1 := server.ExternalIP
+			got1 := server.ExternalIP.String()
 			if got1 != tt.want {
 				t.Errorf("server.ExternalIP = %s, want %s\n", got1, tt.want)
 				t.Errorf("server.Args.Port = %s\n", server.Args.Port)
 			}
-			got2 := server2.ExternalIP
+			got2 := server2.ExternalIP.String()
 			if got2 != tt.want {
 				t.Errorf("server2.ExternalIP = %s, want %s\n", got2, tt.want)
 				t.Errorf("server2.Args.Port = %s\n", server2.Args.Port)

server/server.go

@@ -41,7 +41,7 @@ type Server struct {
 	PeerSubs         map[string]*FederatedServer
 	PeerSubsMut      sync.RWMutex
 	NumPeerSubs      *int64
-	ExternalIP		 string
+	ExternalIP       net.IP
 	pb.UnimplementedHubServer
 }
 
@@ -202,7 +202,7 @@ func MakeHubServer(ctx context.Context, args *Args) *Server {
 		PeerSubs:         make(map[string]*FederatedServer),
 		PeerSubsMut:      sync.RWMutex{},
 		NumPeerSubs:      numSubs,
-		ExternalIP:       "",
+		ExternalIP:       net.IPv4(127,0,0,1),
 	}
 
 	// Start up our background services

server/udp.go

@@ -2,7 +2,6 @@ package server
 
 import (
 	"encoding/binary"
-	"fmt"
 	"net"
 	"strconv"
 	"strings"
@@ -137,8 +136,8 @@ func EncodeAddress(addr string) []byte {
 }
 
 // DecodeAddress gets the string ipv4 address from an SPVPong struct.
-func (pong *SPVPong) DecodeAddress() string {
-	return fmt.Sprintf("%d.%d.%d.%d",
+func (pong *SPVPong) DecodeAddress() net.IP {
+	return net.IPv4(
 		pong.srcAddrRaw[0],
 		pong.srcAddrRaw[1],
 		pong.srcAddrRaw[2],
@@ -148,40 +147,40 @@ func (pong *SPVPong) DecodeAddress() string {
 
 // UDPPing sends a ping over udp to another hub and returns the ip address of
 // this hub.
-func UDPPing(ip, port string) (string, error) {
+func UDPPing(ip, port string) (net.IP, error) {
 	address := ip + ":" + port
 	addr, err := net.ResolveUDPAddr("udp", address)
 	if err != nil {
-		return "", err
+		return net.IP{}, err
 	}
 
 	conn, err := net.DialUDP("udp", nil, addr)
 	if err != nil {
-		return "", err
+		return net.IP{}, err
 	}
 
 	defer conn.Close()
 
 	_, err = conn.Write(encodeSPVPing())
 	if err != nil {
-		return "", err
+		return net.IP{}, err
 	}
 
 	buffer := make([]byte, maxBufferSize)
 	deadline := time.Now().Add(time.Second)
 	err = conn.SetReadDeadline(deadline)
 	if err != nil {
-		return "", err
+		return net.IP{}, err
 	}
 	n, _, err := conn.ReadFromUDP(buffer)
 	if err != nil {
-		return "", err
+		return net.IP{}, err
 	}
 
 	pong := decodeSPVPong(buffer[:n])
 
 	if pong == nil {
-		return "", errors.Base("Pong decoding failed")
+		return net.IP{}, errors.Base("Pong decoding failed")
 	}
 
 	myAddr := pong.DecodeAddress()