From 596a49c1121be3419f92fe55e1b64d02f8adbb0f Mon Sep 17 00:00:00 2001
From: Jakob Borg <jakob@nym.se>
Date: Mon, 14 Sep 2015 10:21:55 +0200
Subject: [PATCH] Invert initialization dependence on relay/conns

This makes it so we can initialize the relay management and then give
that to the connection management, instead of the other way around.

This is important to me in the discovery revamp I'm doing, as otherwise
I get a circular dependency when constructing stuff, with relaying
depending on connection, connection depending on discovery, and
discovery depending on relaying.

With this fixed, discovery will depend on relaying, and connection will
depend on both discovery and relaying.
---
 cmd/syncthing/connections.go | 15 ++++++++++++++-
 cmd/syncthing/main.go        | 15 +++++++++------
 lib/relay/relay.go           | 17 ++++++++++++-----
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/cmd/syncthing/connections.go b/cmd/syncthing/connections.go
index 7b175e842..f02489ee1 100644
--- a/cmd/syncthing/connections.go
+++ b/cmd/syncthing/connections.go
@@ -22,6 +22,7 @@ import (
 	"github.com/syncthing/syncthing/lib/events"
 	"github.com/syncthing/syncthing/lib/model"
 	"github.com/syncthing/syncthing/lib/osutil"
+	"github.com/syncthing/syncthing/lib/relay"
 
 	"github.com/thejerf/suture"
 )
@@ -44,6 +45,7 @@ type connectionSvc struct {
 	tlsCfg     *tls.Config
 	discoverer *discover.Discoverer
 	conns      chan model.IntermediateConnection
+	relaySvc   *relay.Svc
 
 	lastRelayCheck map[protocol.DeviceID]time.Time
 
@@ -52,7 +54,7 @@ type connectionSvc struct {
 	relaysEnabled bool
 }
 
-func newConnectionSvc(cfg *config.Wrapper, myID protocol.DeviceID, mdl *model.Model, tlsCfg *tls.Config, discoverer *discover.Discoverer) *connectionSvc {
+func newConnectionSvc(cfg *config.Wrapper, myID protocol.DeviceID, mdl *model.Model, tlsCfg *tls.Config, discoverer *discover.Discoverer, relaySvc *relay.Svc) *connectionSvc {
 	svc := &connectionSvc{
 		Supervisor: suture.NewSimple("connectionSvc"),
 		cfg:        cfg,
@@ -60,6 +62,7 @@ func newConnectionSvc(cfg *config.Wrapper, myID protocol.DeviceID, mdl *model.Mo
 		model:      mdl,
 		tlsCfg:     tlsCfg,
 		discoverer: discoverer,
+		relaySvc:   relaySvc,
 		conns:      make(chan model.IntermediateConnection),
 
 		connType:       make(map[protocol.DeviceID]model.ConnectionType),
@@ -104,6 +107,10 @@ func newConnectionSvc(cfg *config.Wrapper, myID protocol.DeviceID, mdl *model.Mo
 	}
 	svc.Add(serviceFunc(svc.handle))
 
+	if svc.relaySvc != nil {
+		svc.Add(serviceFunc(svc.acceptRelayConns))
+	}
+
 	return svc
 }
 
@@ -385,6 +392,12 @@ func (s *connectionSvc) connect() {
 	}
 }
 
+func (s *connectionSvc) acceptRelayConns() {
+	for {
+		s.conns <- s.relaySvc.Accept()
+	}
+}
+
 func (s *connectionSvc) shouldLimit(addr net.Addr) bool {
 	if s.cfg.Options().LimitBandwidthInLan {
 		return true
diff --git a/cmd/syncthing/main.go b/cmd/syncthing/main.go
index 04fa9eb1f..6210136ed 100644
--- a/cmd/syncthing/main.go
+++ b/cmd/syncthing/main.go
@@ -711,16 +711,19 @@ func syncthingMain() {
 
 	setupGUI(mainSvc, cfg, m, apiSub, discoverer)
 
+	// Start relay management
+
+	var relaySvc *relay.Svc
+	if opts.RelaysEnabled && (opts.GlobalAnnEnabled || opts.RelayWithoutGlobalAnn) {
+		relaySvc = relay.NewSvc(cfg, tlsCfg)
+		mainSvc.Add(relaySvc)
+	}
+
 	// Start connection management
 
-	connectionSvc := newConnectionSvc(cfg, myID, m, tlsCfg, discoverer)
+	connectionSvc := newConnectionSvc(cfg, myID, m, tlsCfg, discoverer, relaySvc)
 	mainSvc.Add(connectionSvc)
 
-	if opts.RelaysEnabled && (opts.GlobalAnnEnabled || opts.RelayWithoutGlobalAnn) {
-		relaySvc = relay.NewSvc(cfg, tlsCfg, connectionSvc.conns)
-		connectionSvc.Add(relaySvc)
-	}
-
 	if cpuProfile {
 		f, err := os.Create(fmt.Sprintf("cpu-%d.pprof", os.Getpid()))
 		if err != nil {
diff --git a/lib/relay/relay.go b/lib/relay/relay.go
index e97bb1107..a651a2156 100644
--- a/lib/relay/relay.go
+++ b/lib/relay/relay.go
@@ -25,7 +25,9 @@ import (
 	"github.com/thejerf/suture"
 )
 
-func NewSvc(cfg *config.Wrapper, tlsCfg *tls.Config, conns chan<- model.IntermediateConnection) *Svc {
+func NewSvc(cfg *config.Wrapper, tlsCfg *tls.Config) *Svc {
+	conns := make(chan model.IntermediateConnection)
+
 	svc := &Svc{
 		Supervisor: suture.New("Svc", suture.Spec{
 			Log: func(log string) {
@@ -40,11 +42,11 @@ func NewSvc(cfg *config.Wrapper, tlsCfg *tls.Config, conns chan<- model.Intermed
 		cfg:    cfg,
 		tlsCfg: tlsCfg,
 
-		tokens:  make(map[string]suture.ServiceToken),
-		clients: make(map[string]*client.ProtocolClient),
-		mut:     sync.NewRWMutex(),
-
+		tokens:      make(map[string]suture.ServiceToken),
+		clients:     make(map[string]*client.ProtocolClient),
+		mut:         sync.NewRWMutex(),
 		invitations: make(chan protocol.SessionInvitation),
+		conns:       conns,
 	}
 
 	rcfg := cfg.Raw()
@@ -72,6 +74,7 @@ type Svc struct {
 	clients     map[string]*client.ProtocolClient
 	mut         sync.RWMutex
 	invitations chan protocol.SessionInvitation
+	conns       chan model.IntermediateConnection
 }
 
 func (s *Svc) VerifyConfiguration(from, to config.Configuration) error {
@@ -207,6 +210,10 @@ func (s *Svc) ClientStatus() map[string]bool {
 	return status
 }
 
+func (s *Svc) Accept() model.IntermediateConnection {
+	return <-s.conns
+}
+
 type invitationReceiver struct {
 	invitations chan protocol.SessionInvitation
 	tlsCfg      *tls.Config