From 51ffdf87d412d5802c23ef85127803d3df33f96f Mon Sep 17 00:00:00 2001
From: Jakub Sztandera <kubuxu@protonmail.ch>
Date: Fri, 26 Aug 2016 18:45:28 +0200
Subject: [PATCH] nat: do not shortcircuit permanent mappings

If we use same NAT agent and call for the same permanent mapping
again we get the same mapping, no harm done.

If router dies, we will remap again.
Just pros, no cons.
---
 p2p/nat/nat.go | 30 ++++++++----------------------
 1 file changed, 8 insertions(+), 22 deletions(-)

diff --git a/p2p/nat/nat.go b/p2p/nat/nat.go
index 6324715..a7fc75b 100644
--- a/p2p/nat/nat.go
+++ b/p2p/nat/nat.go
@@ -163,6 +163,8 @@ type mapping struct {
 	intaddr   ma.Multiaddr
 	proc      goprocess.Process
 
+	comment string
+
 	cached    ma.Multiaddr
 	cacheTime time.Time
 	cacheLk   sync.Mutex
@@ -198,18 +200,6 @@ func (m *mapping) setExternalPort(p int) {
 	m.extport = p
 }
 
-func (m *mapping) setPermanent(p bool) {
-	m.Lock()
-	defer m.Unlock()
-	m.permanent = p
-}
-
-func (m *mapping) isPermanent() bool {
-	m.Lock()
-	defer m.Unlock()
-	return m.permanent
-}
-
 func (m *mapping) InternalAddr() ma.Multiaddr {
 	m.Lock()
 	defer m.Unlock()
@@ -346,20 +336,17 @@ func (nat *NAT) NewMapping(maddr ma.Multiaddr) (Mapping, error) {
 
 func (nat *NAT) establishMapping(m *mapping) {
 	oldport := m.ExternalPort()
-	if oldport != 0 && m.isPermanent() {
-		// mapping was already established and it is permanent
-		return
-	}
 
 	log.Debugf("Attempting port map: %s/%d", m.Protocol(), m.InternalPort())
-	permanent := false
-
-	newport, err := nat.nat.AddPortMapping(m.Protocol(), m.InternalPort(), "libp2p", MappingDuration)
+	comment := "libp2p"
+	if m.comment != "" {
+		comment = "libp2p-" + m.comment
+	}
 
+	newport, err := nat.nat.AddPortMapping(m.Protocol(), m.InternalPort(), comment, MappingDuration)
 	if err != nil {
 		// Some hardware does not support mappings with timeout, so try that
-		newport, err = nat.nat.AddPortMapping(m.Protocol(), m.InternalPort(), "libp2p", 0)
-		permanent = (err == nil)
+		newport, err = nat.nat.AddPortMapping(m.Protocol(), m.InternalPort(), comment, 0)
 	}
 
 	failure := func() {
@@ -379,7 +366,6 @@ func (nat *NAT) establishMapping(m *mapping) {
 		return
 	}
 
-	m.setPermanent(permanent)
 	m.setExternalPort(newport)
 	ext, err := m.ExternalAddr()
 	if err != nil {
-- 
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