From 12c0e019dc6114626fe4ed76f6f17e379a576484 Mon Sep 17 00:00:00 2001
From: Arceliar <Arceliar@users.noreply.github.com>
Date: Tue, 22 Jan 2019 21:16:41 -0600
Subject: [PATCH] only create one interface, but still opens duplicate
 connections before it catches this, so more work is needed

---
 src/yggdrasil/link.go | 61 +++++++++++++++++++++++++++++++------------
 src/yggdrasil/tcp.go  | 10 ++++---
 2 files changed, 51 insertions(+), 20 deletions(-)

diff --git a/src/yggdrasil/link.go b/src/yggdrasil/link.go
index ddd7db9..0953e4f 100644
--- a/src/yggdrasil/link.go
+++ b/src/yggdrasil/link.go
@@ -8,13 +8,21 @@ import (
 	"time"
 
 	"github.com/yggdrasil-network/yggdrasil-go/src/crypto"
-	//"github.com/yggdrasil-network/yggdrasil-go/src/util"
+	"github.com/yggdrasil-network/yggdrasil-go/src/util"
 )
 
 type link struct {
 	core       *Core
 	mutex      sync.RWMutex // protects interfaces below
-	interfaces map[string]*linkInterface
+	interfaces map[linkInfo]*linkInterface
+}
+
+type linkInfo struct {
+	box      crypto.BoxPubKey // Their encryption key
+	sig      crypto.SigPubKey // Their signing key
+	linkType string           // Type of link, e.g. TCP, AWDL
+	local    string           // Local name or address
+	remote   string           // Remote name or address
 }
 
 type linkInterfaceMsgIO interface {
@@ -27,16 +35,18 @@ type linkInterfaceMsgIO interface {
 }
 
 type linkInterface struct {
-	name  string
-	link  *link
-	peer  *peer
-	msgIO linkInterfaceMsgIO
+	name   string
+	link   *link
+	peer   *peer
+	msgIO  linkInterfaceMsgIO
+	info   linkInfo
+	closed chan struct{}
 }
 
 func (l *link) init(c *Core) error {
 	l.core = c
 	l.mutex.Lock()
-	l.interfaces = make(map[string]*linkInterface)
+	l.interfaces = make(map[linkInfo]*linkInterface)
 	l.mutex.Unlock()
 
 	if err := l.core.awdl.init(c); err != nil {
@@ -47,18 +57,19 @@ func (l *link) init(c *Core) error {
 	return nil
 }
 
-func (l *link) create(msgIO linkInterfaceMsgIO, name string) (*linkInterface, error) {
-	l.mutex.Lock()
-	defer l.mutex.Unlock()
-	if _, ok := l.interfaces[name]; ok {
-		return nil, errors.New("Interface with this name already exists")
-	}
+func (l *link) create(msgIO linkInterfaceMsgIO, name, linkType, local, remote string) (*linkInterface, error) {
+	// Technically anything unique would work for names, but lets pick something human readable, just for debugging
 	intf := linkInterface{
 		name:  name,
 		link:  l,
 		msgIO: msgIO,
+		info: linkInfo{
+			linkType: linkType,
+			local:    local,
+			remote:   remote,
+		},
 	}
-	l.interfaces[intf.name] = &intf
+	//l.interfaces[intf.name] = &intf
 	//go intf.start()
 	return &intf, nil
 }
@@ -89,7 +100,25 @@ func (intf *linkInterface) handler() error {
 		intf.link.core.log.Println("Failed to connect to node: " + intf.name + " version: " + fmt.Sprintf("%d.%d", meta.ver, meta.minorVer))
 		return errors.New("failed to connect: wrong version")
 	}
-	// FIXME we *must* stop here and check that we don't already have a connection to this peer. Need to figure out a sane way how to do that. Otherwise you'll have things like duplicate connections (one in each direction) for auto-discovered peers.
+	// Check if we already have a link to this node
+	intf.info.box = meta.box
+	intf.info.sig = meta.sig
+	intf.link.mutex.Lock()
+	if oldIntf, isIn := intf.link.interfaces[intf.info]; isIn {
+		intf.link.mutex.Unlock()
+		// FIXME we should really return an error and let the caller block instead
+		// That lets them do things like close connections before blocking
+		intf.link.core.log.Println("DEBUG: found existing interface for", intf.name)
+		<-oldIntf.closed
+		return nil
+	} else {
+		intf.closed = make(chan struct{})
+		intf.link.interfaces[intf.info] = intf
+		defer close(intf.closed)
+		intf.link.core.log.Println("DEBUG: registered interface for", intf.name)
+	}
+	intf.link.mutex.Unlock()
+	// Create peer
 	shared := crypto.GetSharedKey(myLinkPriv, &meta.link)
 	intf.peer = intf.link.core.peers.newPeer(&meta.box, &meta.sig, shared, intf.name)
 	if intf.peer == nil {
@@ -111,7 +140,6 @@ func (intf *linkInterface) handler() error {
 	go intf.peer.linkLoop()
 	// Start the writer
 	go func() {
-		// TODO util.PutBytes etc.
 		interval := 4 * time.Second
 		timer := time.NewTimer(interval)
 		clearTimer := func() {
@@ -142,6 +170,7 @@ func (intf *linkInterface) handler() error {
 					return
 				}
 				intf.msgIO.writeMsg(msg)
+				util.PutBytes(msg)
 				if true {
 					// TODO *don't* do this if we're not reading any traffic
 					// In such a case, the reader is responsible for resetting it the next time we read something
diff --git a/src/yggdrasil/tcp.go b/src/yggdrasil/tcp.go
index d2d20a7..b2efbbe 100644
--- a/src/yggdrasil/tcp.go
+++ b/src/yggdrasil/tcp.go
@@ -285,15 +285,17 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
 	iface.setExtraOptions(sock)
 	stream := stream{}
 	stream.init(sock, nil)
-	name := sock.LocalAddr().String() + sock.RemoteAddr().String()
-	link, err := iface.core.link.create(&stream, name)
+	local, _, _ := net.SplitHostPort(sock.LocalAddr().String())
+	remote, _, _ := net.SplitHostPort(sock.RemoteAddr().String())
+	name := "tcp://" + sock.RemoteAddr().String()
+	link, err := iface.core.link.create(&stream, name, "tcp", local, remote)
 	if err != nil {
 		iface.core.log.Println(err)
 		panic(err)
 	}
-	iface.core.log.Println("DEBUG: starting handler")
+	iface.core.log.Println("DEBUG: starting handler for", name)
 	link.handler()
-	iface.core.log.Println("DEBUG: stopped handler")
+	iface.core.log.Println("DEBUG: stopped handler for", name)
 }
 
 // This exchanges/checks connection metadata, sets up the peer struct, sets up the writer goroutine, and then runs the reader within the current goroutine.