From 2ef823e69c7fd25cb6f1b18e3d9ca7ac965e4a9d Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Mon, 4 Mar 2019 23:16:46 +0000
Subject: [PATCH] Fix deadlock when reconfiguring multicast

---
 src/yggdrasil/link.go | 13 ++++++++-----
 src/yggdrasil/tcp.go  |  4 +++-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/yggdrasil/link.go b/src/yggdrasil/link.go
index cbbdb5e9..c4f52a38 100644
--- a/src/yggdrasil/link.go
+++ b/src/yggdrasil/link.go
@@ -76,14 +76,17 @@ func (l *link) init(c *Core) error {
 	go func() {
 		for {
 			e := <-l.reconfigure
-			response := make(chan error)
-			l.tcp.reconfigure <- response
-			if err := <-response; err != nil {
+			tcpresponse := make(chan error)
+			awdlresponse := make(chan error)
+			l.tcp.reconfigure <- tcpresponse
+			if err := <-tcpresponse; err != nil {
 				e <- err
+				continue
 			}
-			l.awdl.reconfigure <- response
-			if err := <-response; err != nil {
+			l.awdl.reconfigure <- awdlresponse
+			if err := <-awdlresponse; err != nil {
 				e <- err
+				continue
 			}
 			e <- nil
 		}
diff --git a/src/yggdrasil/tcp.go b/src/yggdrasil/tcp.go
index 74f14d8a..80d9ccdb 100644
--- a/src/yggdrasil/tcp.go
+++ b/src/yggdrasil/tcp.go
@@ -16,6 +16,7 @@ package yggdrasil
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"math/rand"
 	"net"
@@ -57,10 +58,10 @@ func (t *tcp) getAddr() *net.TCPAddr {
 	// to multicast.go, which obviously is not great, but right now multicast.go
 	// doesn't have the ability to send more than one address in a packet either
 	t.mutex.Lock()
+	defer t.mutex.Unlock()
 	for _, listener := range t.listeners {
 		return listener.Addr().(*net.TCPAddr)
 	}
-	t.mutex.Unlock()
 	return nil
 }
 
@@ -85,6 +86,7 @@ func (t *tcp) init(l *link) error {
 			if len(added) > 0 || len(deleted) > 0 {
 				for _, add := range added {
 					if add[:6] != "tcp://" {
+						e <- errors.New("unknown scheme: " + add)
 						continue
 					}
 					if err := t.listen(add[6:]); err != nil {