From b4a7d56fe3793acd1f3b8283b077086e5c958d43 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Thu, 4 Oct 2018 14:02:59 +0200
Subject: [PATCH] p2p: avoid goroutine for nat.ExtIP

This makes the node URL in logs correct immediately after startup.
---
 p2p/nat/nat.go | 18 ++++++------------
 p2p/server.go  |  9 ++++++++-
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/p2p/nat/nat.go b/p2p/nat/nat.go
index a254648c66..8fad921c48 100644
--- a/p2p/nat/nat.go
+++ b/p2p/nat/nat.go
@@ -129,21 +129,15 @@ func Map(m Interface, c chan struct{}, protocol string, extport, intport int, na
 // ExtIP assumes that the local machine is reachable on the given
 // external IP address, and that any required ports were mapped manually.
 // Mapping operations will not return an error but won't actually do anything.
-func ExtIP(ip net.IP) Interface {
-	if ip == nil {
-		panic("IP must not be nil")
-	}
-	return extIP(ip)
-}
+type ExtIP net.IP
 
-type extIP net.IP
-
-func (n extIP) ExternalIP() (net.IP, error) { return net.IP(n), nil }
-func (n extIP) String() string              { return fmt.Sprintf("ExtIP(%v)", net.IP(n)) }
+func (n ExtIP) ExternalIP() (net.IP, error) { return net.IP(n), nil }
+func (n ExtIP) String() string              { return fmt.Sprintf("ExtIP(%v)", net.IP(n)) }
 
 // These do nothing.
-func (extIP) AddMapping(string, int, int, string, time.Duration) error { return nil }
-func (extIP) DeleteMapping(string, int, int) error                     { return nil }
+
+func (ExtIP) AddMapping(string, int, int, string, time.Duration) error { return nil }
+func (ExtIP) DeleteMapping(string, int, int) error                     { return nil }
 
 // Any returns a port mapper that tries to discover any supported
 // mechanism on the local network.
diff --git a/p2p/server.go b/p2p/server.go
index c62a0e77b8..4e3330c136 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -488,7 +488,14 @@ func (srv *Server) setupLocalNode() error {
 			srv.localnode.Set(e)
 		}
 	}
-	if srv.NAT != nil {
+	switch srv.NAT.(type) {
+	case nil:
+		// No NAT interface, do nothing.
+	case nat.ExtIP:
+		// ExtIP doesn't block, set the IP right away.
+		ip, _ := srv.NAT.ExternalIP()
+		srv.localnode.SetStaticIP(ip)
+	default:
 		// Ask the router about the IP. This takes a while and blocks startup,
 		// do it in the background.
 		srv.loopWG.Add(1)