fix some crashes with races during peer setup

src/yggdrasil/link.go

@@ -217,9 +217,23 @@ func (intf *linkInterface) handler() error {
 	intf.link.mutex.Unlock()
 	// Create peer
 	shared := crypto.GetSharedKey(myLinkPriv, &meta.link)
+	out := func(msgs [][]byte) {
+		// nil to prevent it from blocking if the link is somehow frozen
+		// this is safe because another packet won't be sent until the link notifies
+		//  the peer that it's ready for one
+		intf.writer.sendFrom(nil, msgs, false)
+	}
+	linkOut := func(bs []byte) {
+		// nil to prevent it from blocking if the link is somehow frozen
+		// FIXME this is hypothetically not safe, the peer shouldn't be sending
+		//  additional packets until this one finishes, otherwise this could leak
+		//  memory if writing happens slower than link packets are generated...
+		//  that seems unlikely, so it's a lesser evil than deadlocking for now
+		intf.writer.sendFrom(nil, [][]byte{bs}, true)
+	}
 	phony.Block(&intf.link.core.peers, func() {
 		// FIXME don't use phony.Block, it's bad practice, even if it's safe here
-		intf.peer = intf.link.core.peers._newPeer(&meta.box, &meta.sig, shared, intf, func() { intf.msgIO.close() })
+		intf.peer = intf.link.core.peers._newPeer(&meta.box, &meta.sig, shared, intf, func() { intf.msgIO.close() }, out, linkOut)
 	})
 	if intf.peer == nil {
 		return errors.New("failed to create peer")
@@ -228,20 +242,6 @@ func (intf *linkInterface) handler() error {
 		// More cleanup can go here
 		intf.peer.Act(nil, intf.peer._removeSelf)
 	}()
-	intf.peer.out = func(msgs [][]byte) {
-		// nil to prevent it from blocking if the link is somehow frozen
-		// this is safe because another packet won't be sent until the link notifies
-		//  the peer that it's ready for one
-		intf.writer.sendFrom(nil, msgs, false)
-	}
-	intf.peer.linkOut = func(bs []byte) {
-		// nil to prevent it from blocking if the link is somehow frozen
-		// FIXME this is hypothetically not safe, the peer shouldn't be sending
-		//  additional packets until this one finishes, otherwise this could leak
-		//  memory if writing happens slower than link packets are generated...
-		//  that seems unlikely, so it's a lesser evil than deadlocking for now
-		intf.writer.sendFrom(nil, [][]byte{bs}, true)
-	}
 	themAddr := address.AddrForNodeID(crypto.GetNodeID(&intf.info.box))
 	themAddrString := net.IP(themAddr[:]).String()
 	themString := fmt.Sprintf("%s@%s", themAddrString, intf.info.remote)

src/yggdrasil/peer.go

@@ -123,7 +123,7 @@ func (ps *peers) _updatePeers() {
 }
 
 // Creates a new peer with the specified box, sig, and linkShared keys, using the lowest unoccupied port number.
-func (ps *peers) _newPeer(box *crypto.BoxPubKey, sig *crypto.SigPubKey, linkShared *crypto.BoxSharedKey, intf *linkInterface, closer func()) *peer {
+func (ps *peers) _newPeer(box *crypto.BoxPubKey, sig *crypto.SigPubKey, linkShared *crypto.BoxSharedKey, intf *linkInterface, closer func(), out func([][]byte), linkOut func([]byte)) *peer {
 	now := time.Now()
 	p := peer{box: *box,
 		sig:        *sig,
@@ -134,6 +134,8 @@ func (ps *peers) _newPeer(box *crypto.BoxPubKey, sig *crypto.SigPubKey, linkShar
 		close:      closer,
 		core:       ps.core,
 		intf:       intf,
+		out:        out,
+		linkOut:    linkOut,
 	}
 	oldPorts := ps.ports
 	newPorts := make(map[switchPort]*peer)

src/yggdrasil/router.go

@@ -62,17 +62,17 @@ func (r *router) init(core *Core) {
 		},
 	}
 	var p *peer
-	phony.Block(&r.core.peers, func() {
-		// FIXME don't block here!
-		p = r.core.peers._newPeer(&r.core.boxPub, &r.core.sigPub, &crypto.BoxSharedKey{}, &self, nil)
-	})
-	p.out = func(packets [][]byte) {
+	peerOut := func(packets [][]byte) {
 		r.handlePackets(p, packets)
 		r.Act(p, func() {
 			// after the router handle the packets, notify the peer that it's ready for more
 			p.Act(r, p._handleIdle)
 		})
 	}
+	phony.Block(&r.core.peers, func() {
+		// FIXME don't block here!
+		p = r.core.peers._newPeer(&r.core.boxPub, &r.core.sigPub, &crypto.BoxSharedKey{}, &self, nil, peerOut, nil)
+	})
 	p.Act(r, p._handleIdle)
 	r.out = func(bs []byte) { p.handlePacketFrom(r, bs) }
 	r.nodeinfo.init(r.core)

src/yggdrasil/simlink.go

@@ -57,7 +57,11 @@ func (s *Simlink) writeMsgs(msgs [][]byte) (int, error) {
 func (c *Core) NewSimlink() *Simlink {
 	s := &Simlink{rch: make(chan []byte, 1)}
 	n := "Simlink"
-	s.link, _ = c.link.create(s, n, n, n, n, false, true)
+	var err error
+	s.link, err = c.link.create(s, n, n, n, n, false, true)
+	if err != nil {
+		panic(err)
+	}
 	return s
 }