From 8c05e9b25280e21d0c8f77cb5c803d72b4d4a2cc Mon Sep 17 00:00:00 2001
From: Anton Evangelatov <anton.evangelatov@gmail.com>
Date: Sun, 4 Mar 2018 16:17:49 +0100
Subject: [PATCH] p2p/sim, swarm/network: re-use externalIP method

---
 p2p/simulations/adapters/exec.go              | 33 ++++++++++---------
 .../simulations/discovery/discovery_test.go   | 16 +--------
 2 files changed, 18 insertions(+), 31 deletions(-)

diff --git a/p2p/simulations/adapters/exec.go b/p2p/simulations/adapters/exec.go
index 18a8073c62..64a4704d48 100644
--- a/p2p/simulations/adapters/exec.go
+++ b/p2p/simulations/adapters/exec.go
@@ -338,6 +338,21 @@ type execNodeConfig struct {
 	PeerAddrs map[string]string `json:"peer_addrs,omitempty"`
 }
 
+// ExternalIP gets an external IP address so that Enode URL is usable
+func ExternalIP() net.IP {
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		log.Crit("error getting IP address", "err", err)
+	}
+	for _, addr := range addrs {
+		if ip, ok := addr.(*net.IPNet); ok && !ip.IP.IsLoopback() {
+			return ip.IP
+		}
+	}
+	log.Crit("unable to determine explicit IP address")
+	return net.IP{127, 0, 0, 1}
+}
+
 // execP2PNode starts a devp2p node when the current binary is executed with
 // argv[0] being "p2p-node", reading the service / ID from argv[1] / argv[2]
 // and the node config from the _P2P_NODE_CONFIG environment variable
@@ -361,25 +376,11 @@ func execP2PNode() {
 	conf.Stack.P2P.PrivateKey = conf.Node.PrivateKey
 	conf.Stack.Logger = log.New("node.id", conf.Node.ID.String())
 
-	// use explicit IP address in ListenAddr so that Enode URL is usable
-	externalIP := func() string {
-		addrs, err := net.InterfaceAddrs()
-		if err != nil {
-			log.Crit("error getting IP address", "err", err)
-		}
-		for _, addr := range addrs {
-			if ip, ok := addr.(*net.IPNet); ok && !ip.IP.IsLoopback() {
-				return ip.IP.String()
-			}
-		}
-		log.Crit("unable to determine explicit IP address")
-		return ""
-	}
 	if strings.HasPrefix(conf.Stack.P2P.ListenAddr, ":") {
-		conf.Stack.P2P.ListenAddr = externalIP() + conf.Stack.P2P.ListenAddr
+		conf.Stack.P2P.ListenAddr = ExternalIP().String() + conf.Stack.P2P.ListenAddr
 	}
 	if conf.Stack.WSHost == "0.0.0.0" {
-		conf.Stack.WSHost = externalIP()
+		conf.Stack.WSHost = ExternalIP().String()
 	}
 
 	// initialize the devp2p stack
diff --git a/swarm/network/simulations/discovery/discovery_test.go b/swarm/network/simulations/discovery/discovery_test.go
index 76b67d598f..2782aa84a5 100644
--- a/swarm/network/simulations/discovery/discovery_test.go
+++ b/swarm/network/simulations/discovery/discovery_test.go
@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"io/ioutil"
 	"math/rand"
-	"net"
 	"os"
 	"sync"
 	"testing"
@@ -307,21 +306,8 @@ func triggerChecks(trigger chan discover.NodeID, net *simulations.Network, id di
 	return nil
 }
 
-// getOutboundIP gets preferred outbound ip of this machine/container
-func getOutboundIP() net.IP {
-	conn, err := net.Dial("udp", "8.8.8.8:80")
-	if err != nil {
-		panic(err)
-	}
-	defer conn.Close()
-
-	localAddr := conn.LocalAddr().(*net.UDPAddr)
-
-	return localAddr.IP
-}
-
 func newService(ctx *adapters.ServiceContext) (node.Service, error) {
-	host := getOutboundIP()
+	host := adapters.ExternalIP()
 
 	addr := network.NewAddrFromNodeIDAndPort(ctx.Config.ID, host, ctx.Config.Port)