Merge pull request #199 from enzoh/master

Publicize NAT manager struct

p2p/host/basic/basic_host.go

@@ -56,7 +56,7 @@ type BasicHost struct {
 	network inet.Network
 	mux     *msmux.MultistreamMuxer
 	ids     *identify.IDService
-	natmgr  *natManager
+	natmgr  NATManager
 	addrs   AddrsFactory
 
 	negtimeout time.Duration
@@ -88,11 +88,7 @@ type HostOpts struct {
 
 	// NATManager takes care of setting NAT port mappings, and discovering external addresses.
 	// If omitted, this will simply be disabled.
-	//
-	// TODO: Currently the NATManager can only be enabled by calling New,
-	//       since the underlying struct and functions are still private.
-	//       Once they are public, NATManager can be used through NewHost as well.
-	NATManager *natManager
+	NATManager NATManager
 
 	//
 	BandwidthReporter metrics.Reporter

p2p/host/basic/natmgr.go

@@ -4,14 +4,32 @@ import (
 	"context"
 	"sync"
 
-	inat "github.com/libp2p/go-libp2p-nat"
-
 	goprocess "github.com/jbenet/goprocess"
-	lgbl "github.com/libp2p/go-libp2p-loggables"
+	inat "github.com/libp2p/go-libp2p-nat"
 	inet "github.com/libp2p/go-libp2p-net"
+	lgbl "github.com/libp2p/go-libp2p-loggables"
 	ma "github.com/multiformats/go-multiaddr"
 )
 
+// A simple interface to manage NAT devices. 
+type NATManager interface {
+
+	// Get the NAT device managed by the NAT manager.
+	NAT() *inat.NAT
+
+	// Receive a notification when the NAT device is ready for use.
+	Ready() <-chan struct{}
+
+	// Close all resources associated with a NAT manager.
+	Close() error
+
+}
+
+// Create a NAT manager.
+func NewNATManager(net inet.Network) NATManager {
+	return newNatManager(net)
+}
+
 // natManager takes care of adding + removing port mappings to the nat.
 // Initialized with the host if it has a NATPortMap option enabled.
 // natManager receives signals from the network, and check on nat mappings: