From 20cc417a53e22a742adaaabc6b5033af2eebffa2 Mon Sep 17 00:00:00 2001
From: Juan Batiz-Benet <juan@benet.ai>
Date: Wed, 5 Nov 2014 01:47:02 -0800
Subject: [PATCH] added ipv6 link-local loopback

---
 net/convert.go  | 18 +++++++++++++++++-
 net/net_test.go | 12 ++++++++++--
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/net/convert.go b/net/convert.go
index d1dc7af..9062a46 100644
--- a/net/convert.go
+++ b/net/convert.go
@@ -1,6 +1,7 @@
 package manet
 
 import (
+	"bytes"
 	"fmt"
 	"net"
 	"strings"
@@ -14,6 +15,9 @@ var (
 
 	// IP6Loopback is the ip6 loopback multiaddr
 	IP6Loopback = ma.StringCast("/ip6/::1")
+
+	// IP6LinkLocalLoopback is the ip6 link-local loopback multiaddr
+	IP6LinkLocalLoopback = ma.StringCast("/ip6/fe80::1")
 )
 
 var errIncorrectNetAddr = fmt.Errorf("incorrect network addr conversion")
@@ -169,5 +173,17 @@ func IsThinWaist(m ma.Multiaddr) bool {
 // IsIPLoopback returns whether a Multiaddr is a "Loopback" IP address
 // This means either /ip4/127.0.0.1 or /ip6/::1
 func IsIPLoopback(m ma.Multiaddr) bool {
-	return m.Equal(IP4Loopback) || m.Equal(IP6Loopback)
+	b := m.Bytes()
+
+	// /ip4/127 prefix (_entire_ /8 is loopback...)
+	if bytes.HasPrefix(b, []byte{4, 127}) {
+		return true
+	}
+
+	// /ip6/::1
+	if IP6Loopback.Equal(m) || IP6LinkLocalLoopback.Equal(m) {
+		return true
+	}
+
+	return false
 }
diff --git a/net/net_test.go b/net/net_test.go
index c212c7c..bd01f3c 100644
--- a/net/net_test.go
+++ b/net/net_test.go
@@ -208,11 +208,19 @@ func TestLoopback(t *testing.T) {
 		t.Error("IP6Loopback incorrect:", IP6Loopback)
 	}
 
+	if IP6LinkLocalLoopback.String() != "/ip6/fe80::1" {
+		t.Error("IP6LinkLocalLoopback incorrect:", IP6Loopback)
+	}
+
 	if !IsIPLoopback(IP4Loopback) {
-		t.Error("IsIPLoopback failed (IP4)")
+		t.Error("IsIPLoopback failed (IP4Loopback)")
 	}
 
 	if !IsIPLoopback(IP6Loopback) {
-		t.Error("IsIPLoopback failed (IP6)")
+		t.Error("IsIPLoopback failed (IP6Loopback)")
+	}
+
+	if !IsIPLoopback(IP6LinkLocalLoopback) {
+		t.Error("IsIPLoopback failed (IP6LinkLocalLoopback)")
 	}
 }