From 0b8f5b5dda8122b7563b3207a2dcb981d1055cc6 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Sun, 21 Apr 2019 12:28:46 +0100
Subject: [PATCH] Tweaks

---
 src/tuntap/tun.go     | 18 +++++++++---------
 src/yggdrasil/conn.go | 17 ++++++++++-------
 2 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/src/tuntap/tun.go b/src/tuntap/tun.go
index acdcf3a1..d9e0e77e 100644
--- a/src/tuntap/tun.go
+++ b/src/tuntap/tun.go
@@ -170,7 +170,7 @@ func (tun *TunAdapter) handler() error {
 		// Accept the incoming connection
 		conn, err := tun.listener.Accept()
 		if err != nil {
-			tun.log.Errorln("TUN/TAP error accepting connection:", err)
+			tun.log.Errorln("TUN/TAP connection accept error:", err)
 			return err
 		}
 		go tun.connReader(conn)
@@ -195,7 +195,7 @@ func (tun *TunAdapter) connReader(conn *yggdrasil.Conn) error {
 	for {
 		n, err := conn.Read(b)
 		if err != nil {
-			tun.log.Errorln("TUN/TAP read error:", err)
+			tun.log.Errorln("TUN/TAP conn read error:", err)
 			return err
 		}
 		if n == 0 {
@@ -203,11 +203,11 @@ func (tun *TunAdapter) connReader(conn *yggdrasil.Conn) error {
 		}
 		w, err := tun.iface.Write(b[:n])
 		if err != nil {
-			tun.log.Errorln("TUN/TAP failed to write to interface:", err)
+			tun.log.Errorln("TUN/TAP iface write error:", err)
 			continue
 		}
 		if w != n {
-			tun.log.Errorln("TUN/TAP wrote", w, "instead of", n, "which is bad")
+			tun.log.Errorln("TUN/TAP iface write len didn't match conn read len")
 			continue
 		}
 	}
@@ -231,7 +231,7 @@ func (tun *TunAdapter) ifaceReader() error {
 		if bs[0]&0xf0 == 0x60 {
 			// Check if we have a fully-sized header
 			if len(bs) < 40 {
-				panic("Tried to send a packet shorter than an IPv6 header...")
+				continue
 			}
 			// IPv6 address
 			addrlen = 16
@@ -241,14 +241,14 @@ func (tun *TunAdapter) ifaceReader() error {
 		} else if bs[0]&0xf0 == 0x40 {
 			// Check if we have a fully-sized header
 			if len(bs) < 20 {
-				panic("Tried to send a packet shorter than an IPv4 header...")
+				continue
 			}
 			// IPv4 address
 			addrlen = 4
 			copy(srcAddr[:addrlen], bs[12:])
 			copy(dstAddr[:addrlen], bs[16:])
 		} else {
-			// Unknown address length
+			// Unknown address length or protocol
 			continue
 		}
 		dstNodeID, dstNodeIDMask = dstAddr.GetNodeIDandMask()
@@ -258,7 +258,7 @@ func (tun *TunAdapter) ifaceReader() error {
 			tun.mutex.Unlock()
 			w, err := conn.Write(bs)
 			if err != nil {
-				tun.log.Println("Unable to write to remote:", err)
+				tun.log.Println("TUN/TAP conn write error:", err)
 				continue
 			}
 			if w != n {
@@ -271,7 +271,7 @@ func (tun *TunAdapter) ifaceReader() error {
 				go tun.connReader(&conn)
 			} else {
 				tun.mutex.Unlock()
-				tun.log.Println("Error dialing:", err)
+				tun.log.Println("TUN/TAP dial error:", err)
 			}
 		}
 
diff --git a/src/yggdrasil/conn.go b/src/yggdrasil/conn.go
index ed9eb6cd..977c7421 100644
--- a/src/yggdrasil/conn.go
+++ b/src/yggdrasil/conn.go
@@ -2,6 +2,7 @@ package yggdrasil
 
 import (
 	"errors"
+	"fmt"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -21,6 +22,10 @@ type Conn struct {
 	expired       bool
 }
 
+func (c *Conn) String() string {
+	return fmt.Sprintf("c=%p", c)
+}
+
 // This method should only be called from the router goroutine
 func (c *Conn) startSearch() {
 	searchCompleted := func(sinfo *sessionInfo, err error) {
@@ -76,8 +81,8 @@ func (c *Conn) Read(b []byte) (int, error) {
 	if c.session == nil {
 		return 0, errors.New("searching for remote side")
 	}
-	if !c.session.init.Load().(bool) {
-		return 0, errors.New("waiting for remote side to accept")
+	if init, ok := c.session.init.Load().(bool); !ok || (ok && !init) {
+		return 0, errors.New("waiting for remote side to accept " + c.String())
 	}
 	select {
 	case p, ok := <-c.session.recv:
@@ -129,15 +134,12 @@ func (c *Conn) Write(b []byte) (bytesWritten int, err error) {
 		return 0, errors.New("searching for remote side")
 	}
 	defer util.PutBytes(b)
-	if !c.session.init.Load().(bool) {
-		return 0, errors.New("waiting for remote side to accept")
+	if init, ok := c.session.init.Load().(bool); !ok || (ok && !init) {
+		return 0, errors.New("waiting for remote side to accept " + c.String())
 	}
-	// code isn't multithreaded so appending to this is safe
 	coords := c.session.coords
-	// Prepare the payload
 	c.session.myNonceMutex.Lock()
 	payload, nonce := crypto.BoxSeal(&c.session.sharedSesKey, b, &c.session.myNonce)
-	c.session.myNonceMutex.Unlock()
 	defer util.PutBytes(payload)
 	p := wire_trafficPacket{
 		Coords:  coords,
@@ -146,6 +148,7 @@ func (c *Conn) Write(b []byte) (bytesWritten int, err error) {
 		Payload: payload,
 	}
 	packet := p.encode()
+	c.session.myNonceMutex.Unlock()
 	atomic.AddUint64(&c.session.bytesSent, uint64(len(b)))
 	select {
 	case c.session.send <- packet: