From 304f22dc1d23807d7f612f3d32433121b4876c5c Mon Sep 17 00:00:00 2001
From: Arceliar <Arceliar@users.noreply.github.com>
Date: Thu, 28 Feb 2019 20:05:21 -0600
Subject: [PATCH] re-enable session workers in a way that doesn't block and
 drops packets before decrypting if necessary

---
 src/yggdrasil/router.go  |  7 +------
 src/yggdrasil/session.go | 32 +++++++++++++++++++++++---------
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/src/yggdrasil/router.go b/src/yggdrasil/router.go
index d84b935b..6acd4735 100644
--- a/src/yggdrasil/router.go
+++ b/src/yggdrasil/router.go
@@ -66,7 +66,7 @@ func (r *router) init(core *Core) {
 	r.reconfigure = make(chan chan error, 1)
 	r.addr = *address.AddrForNodeID(&r.core.dht.nodeID)
 	r.subnet = *address.SubnetForNodeID(&r.core.dht.nodeID)
-	in := make(chan []byte, 32) // TODO something better than this...
+	in := make(chan []byte, 1) // TODO something better than this...
 	p := r.core.peers.newPeer(&r.core.boxPub, &r.core.sigPub, &crypto.BoxSharedKey{}, "(self)", nil)
 	p.out = func(packet []byte) { in <- packet }
 	r.in = in
@@ -322,9 +322,6 @@ func (r *router) sendPacket(bs []byte) {
 			// Don't continue - drop the packet
 			return
 		}
-
-		sinfo.doSend(bs)
-		return
 		sinfo.send <- bs
 	}
 }
@@ -404,8 +401,6 @@ func (r *router) handleTraffic(packet []byte) {
 	if !isIn {
 		return
 	}
-	sinfo.doRecv(&p)
-	return
 	sinfo.recv <- &p
 }
 
diff --git a/src/yggdrasil/session.go b/src/yggdrasil/session.go
index bffc149b..012af579 100644
--- a/src/yggdrasil/session.go
+++ b/src/yggdrasil/session.go
@@ -304,7 +304,7 @@ func (ss *sessions) createSession(theirPermKey *crypto.BoxPubKey) *sessionInfo {
 	sinfo.theirSubnet = *address.SubnetForNodeID(crypto.GetNodeID(&sinfo.theirPermPub))
 	sinfo.send = make(chan []byte, 32)
 	sinfo.recv = make(chan *wire_trafficPacket, 32)
-	//go sinfo.doWorker()
+	go sinfo.doWorker()
 	ss.sinfos[sinfo.myHandle] = &sinfo
 	ss.byMySes[sinfo.mySesPub] = &sinfo.myHandle
 	ss.byTheirPerm[sinfo.theirPermPub] = &sinfo.myHandle
@@ -525,17 +525,36 @@ func (ss *sessions) resetInits() {
 // It handles calling the relatively expensive crypto operations.
 // It's also responsible for checking nonces and dropping out-of-date/duplicate packets, or else calling the function to update nonces if the packet is OK.
 func (sinfo *sessionInfo) doWorker() {
+	send := make(chan []byte, 32)
+	defer close(send)
+	go func() {
+		for bs := range send {
+			sinfo.doSend(bs)
+		}
+	}()
+	recv := make(chan *wire_trafficPacket, 32)
+	defer close(recv)
+	go func() {
+		for p := range recv {
+			sinfo.doRecv(p)
+		}
+	}()
 	for {
 		select {
 		case p, ok := <-sinfo.recv:
 			if ok {
-				sinfo.doRecv(p)
+				select {
+				case recv <- p:
+				default:
+					// We need something to not block, and it's best to drop it before we decrypt
+					util.PutBytes(p.Payload)
+				}
 			} else {
 				return
 			}
 		case bs, ok := <-sinfo.send:
 			if ok {
-				sinfo.doSend(bs)
+				send <- bs
 			} else {
 				return
 			}
@@ -625,10 +644,5 @@ func (sinfo *sessionInfo) doRecv(p *wire_trafficPacket) {
 	sinfo.updateNonce(&p.Nonce)
 	sinfo.time = time.Now()
 	sinfo.bytesRecvd += uint64(len(bs))
-	sinfo.core.router.recvPacket(bs, sinfo)
-	return
-	select {
-	case sinfo.core.router.toRecv <- router_recvPacket{bs, sinfo}:
-	default: // avoid deadlocks, maybe do this somewhere else?...
-	}
+	sinfo.core.router.toRecv <- router_recvPacket{bs, sinfo}
 }