refactor session worker code slightly

src/yggdrasil/session.go

@@ -442,50 +442,53 @@ func (sinfo *sessionInfo) recvWorker() {
 	//  Since there's no reason for anywhere else in the session code to need to *read* it...
 	//  Only needs to be updated from the outside if a ping resets it...
 	//  That would get rid of the need to take a mutex for the sessionFunc
+	doRecv := func(p *wire_trafficPacket) {
+		var bs []byte
+		var err error
+		var k crypto.BoxSharedKey
+		sessionFunc := func() {
+			if !sinfo.nonceIsOK(&p.Nonce) {
+				err = ConnError{errors.New("packet dropped due to invalid nonce"), false, true, false, 0}
+				return
+			}
+			k = sinfo.sharedSesKey
+		}
+		sinfo.doFunc(sessionFunc)
+		if err != nil {
+			util.PutBytes(p.Payload)
+			return
+		}
+		var isOK bool
+		bs, isOK = crypto.BoxOpen(&k, p.Payload, &p.Nonce)
+		if !isOK {
+			util.PutBytes(bs)
+			return
+		}
+		sessionFunc = func() {
+			if k != sinfo.sharedSesKey || !sinfo.nonceIsOK(&p.Nonce) {
+				// The session updated in the mean time, so return an error
+				err = ConnError{errors.New("session updated during crypto operation"), false, true, false, 0}
+				return
+			}
+			sinfo.updateNonce(&p.Nonce)
+			sinfo.time = time.Now()
+			sinfo.bytesRecvd += uint64(len(bs))
+		}
+		sinfo.doFunc(sessionFunc)
+		if err != nil {
+			// Not sure what else to do with this packet, I guess just drop it
+			util.PutBytes(bs)
+		} else {
+			// Pass the packet to the buffer for Conn.Read
+			sinfo.recv <- bs
+		}
+	}
 	for {
 		select {
 		case <-sinfo.cancel.Finished():
 			return
 		case p := <-sinfo.fromRouter:
-			var bs []byte
+			doRecv(p)
-			var err error
-			var k crypto.BoxSharedKey
-			sessionFunc := func() {
-				if !sinfo.nonceIsOK(&p.Nonce) {
-					err = ConnError{errors.New("packet dropped due to invalid nonce"), false, true, false, 0}
-					return
-				}
-				k = sinfo.sharedSesKey
-			}
-			sinfo.doFunc(sessionFunc)
-			if err != nil {
-				util.PutBytes(p.Payload)
-				continue
-			}
-			var isOK bool
-			bs, isOK = crypto.BoxOpen(&k, p.Payload, &p.Nonce)
-			if !isOK {
-				util.PutBytes(bs)
-				continue
-			}
-			sessionFunc = func() {
-				if k != sinfo.sharedSesKey || !sinfo.nonceIsOK(&p.Nonce) {
-					// The session updated in the mean time, so return an error
-					err = ConnError{errors.New("session updated during crypto operation"), false, true, false, 0}
-					return
-				}
-				sinfo.updateNonce(&p.Nonce)
-				sinfo.time = time.Now()
-				sinfo.bytesRecvd += uint64(len(bs))
-			}
-			sinfo.doFunc(sessionFunc)
-			if err != nil {
-				// Not sure what else to do with this packet, I guess just drop it
-				util.PutBytes(bs)
-			} else {
-				// Pass the packet to the buffer for Conn.Read
-				sinfo.recv <- bs
-			}
 		}
 	}
 }
@@ -493,33 +496,36 @@ func (sinfo *sessionInfo) recvWorker() {
 func (sinfo *sessionInfo) sendWorker() {
 	// TODO move info that this worker needs here, send updates via a channel
 	//  Otherwise we need to take a mutex to avoid races with update()
+	doSend := func(bs []byte) {
+		var p wire_trafficPacket
+		var k crypto.BoxSharedKey
+		sessionFunc := func() {
+			sinfo.bytesSent += uint64(len(bs))
+			p = wire_trafficPacket{
+				Coords: append([]byte(nil), sinfo.coords...),
+				Handle: sinfo.theirHandle,
+				Nonce:  sinfo.myNonce,
+			}
+			sinfo.myNonce.Increment()
+			k = sinfo.sharedSesKey
+		}
+		// Get the mutex-protected info needed to encrypt the packet
+		sinfo.doFunc(sessionFunc)
+		// Encrypt the packet
+		p.Payload, _ = crypto.BoxSeal(&k, bs, &p.Nonce)
+		packet := p.encode()
+		// Cleanup
+		util.PutBytes(bs)
+		util.PutBytes(p.Payload)
+		// Send the packet
+		sinfo.core.router.out(packet)
+	}
 	for {
 		select {
 		case <-sinfo.cancel.Finished():
 			return
 		case bs := <-sinfo.send:
-			var p wire_trafficPacket
+			doSend(bs)
-			var k crypto.BoxSharedKey
-			sessionFunc := func() {
-				sinfo.bytesSent += uint64(len(bs))
-				p = wire_trafficPacket{
-					Coords: append([]byte(nil), sinfo.coords...),
-					Handle: sinfo.theirHandle,
-					Nonce:  sinfo.myNonce,
-				}
-				sinfo.myNonce.Increment()
-				k = sinfo.sharedSesKey
-			}
-			// Get the mutex-protected info needed to encrypt the packet
-			sinfo.doFunc(sessionFunc)
-			// Encrypt the packet
-			p.Payload, _ = crypto.BoxSeal(&k, bs, &p.Nonce)
-			packet := p.encode()
-			// Cleanup
-			util.PutBytes(bs)
-			util.PutBytes(p.Payload)
-			// Send the packet
-			sinfo.core.router.out(packet)
 		}
 	}
 }