From 0715e829c2b38ed1183d10b942803a3074c01507 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Thu, 28 Mar 2019 09:12:00 +0000
Subject: [PATCH] Fix adapter setup and no longer panics on packets shorter
 than IP header

---
 src/tuntap/icmpv6.go     |  2 +-
 src/tuntap/tun.go        | 20 +++++++++++++++-----
 src/yggdrasil/adapter.go |  3 ++-
 3 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/src/tuntap/icmpv6.go b/src/tuntap/icmpv6.go
index f4f9efe..55c3280 100644
--- a/src/tuntap/icmpv6.go
+++ b/src/tuntap/icmpv6.go
@@ -93,7 +93,7 @@ func (i *ICMPv6) ParsePacket(datain []byte) {
 	}
 
 	// Write the packet to TUN/TAP
-	i.tun.Send <- response
+	i.tun.iface.Write(response)
 }
 
 // Unwraps the ethernet headers of an incoming ICMPv6 packet and hands off
diff --git a/src/tuntap/tun.go b/src/tuntap/tun.go
index 7dab31c..780043f 100644
--- a/src/tuntap/tun.go
+++ b/src/tuntap/tun.go
@@ -107,13 +107,20 @@ func (tun *TunAdapter) Start(a address.Address, s address.Subnet) error {
 		}
 	}
 	if ifname == "none" || ifname == "dummy" {
+		tun.log.Debugln("Not starting TUN/TAP as ifname is none or dummy")
 		return nil
 	}
 	tun.mutex.Lock()
 	tun.isOpen = true
 	tun.mutex.Unlock()
-	go func() { tun.log.Errorln("WARNING: tun.read() exited with error:", tun.Read()) }()
-	go func() { tun.log.Errorln("WARNING: tun.write() exited with error:", tun.Write()) }()
+	go func() {
+		tun.log.Debugln("Starting TUN/TAP reader goroutine")
+		tun.log.Errorln("WARNING: tun.read() exited with error:", tun.Read())
+	}()
+	go func() {
+		tun.log.Debugln("Starting TUN/TAP writer goroutine")
+		tun.log.Errorln("WARNING: tun.write() exited with error:", tun.Write())
+	}()
 	if iftapmode {
 		go func() {
 			for {
@@ -147,12 +154,16 @@ func (tun *TunAdapter) Write() error {
 			var destAddr address.Address
 			if data[0]&0xf0 == 0x60 {
 				if len(data) < 40 {
-					panic("Tried to send a packet shorter than an IPv6 header...")
+					//panic("Tried to send a packet shorter than an IPv6 header...")
+					util.PutBytes(data)
+					continue
 				}
 				copy(destAddr[:16], data[24:])
 			} else if data[0]&0xf0 == 0x40 {
 				if len(data) < 20 {
-					panic("Tried to send a packet shorter than an IPv4 header...")
+					//panic("Tried to send a packet shorter than an IPv4 header...")
+					util.PutBytes(data)
+					continue
 				}
 				copy(destAddr[:4], data[16:])
 			} else {
@@ -255,7 +266,6 @@ func (tun *TunAdapter) Read() error {
 			if !open {
 				return nil
 			} else {
-				// panic(err)
 				return err
 			}
 		}
diff --git a/src/yggdrasil/adapter.go b/src/yggdrasil/adapter.go
index 7437eb0..4103d1e 100644
--- a/src/yggdrasil/adapter.go
+++ b/src/yggdrasil/adapter.go
@@ -29,7 +29,8 @@ type adapterImplementation interface {
 }
 
 // Initialises the adapter.
-func (adapter Adapter) Init(config *config.NodeState, log *log.Logger, send chan<- []byte, recv <-chan []byte) {
+func (adapter *Adapter) Init(config *config.NodeState, log *log.Logger, send chan<- []byte, recv <-chan []byte) {
+	log.Traceln("Adapter setup - given channels:", send, recv)
 	adapter.Send = send
 	adapter.Recv = recv
 	adapter.Reconfigure = make(chan chan error, 1)