From 6571a8c300e97cd4e583f23a6a8df7fc32b6c78f Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Mon, 12 Feb 2018 20:00:55 +0000
Subject: [PATCH] Don't use channels for ICMPv6 packets

---
 src/yggdrasil/icmpv6.go | 42 ++++++++++++++---------------------------
 src/yggdrasil/tun.go    |  7 ++++++-
 2 files changed, 20 insertions(+), 29 deletions(-)

diff --git a/src/yggdrasil/icmpv6.go b/src/yggdrasil/icmpv6.go
index 85d4595..483902b 100644
--- a/src/yggdrasil/icmpv6.go
+++ b/src/yggdrasil/icmpv6.go
@@ -6,7 +6,6 @@ package yggdrasil
 
 import "golang.org/x/net/icmp"
 import "encoding/binary"
-import "errors"
 import "unsafe" // TODO investigate if this can be done without resorting to unsafe
 
 type macAddress [6]byte
@@ -21,7 +20,6 @@ type icmpv6 struct {
 	peerlladdr ipv6Address
 	mymac      macAddress
 	mylladdr   ipv6Address
-	recv       chan []byte
 }
 
 type etherHeader struct {
@@ -76,39 +74,27 @@ type icmpv6Frame struct {
 
 func (i *icmpv6) init(t *tunDevice) {
 	i.tun = t
-	i.recv = make(chan []byte)
 	copy(i.mymac[:], []byte{0x02, 0x00, 0x00, 0x00, 0x00, 0x02})
 	copy(i.mylladdr[:], []byte{
 		0xFE, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xFE})
-	go i.listen()
 }
 
-func (i *icmpv6) listen() {
-	for {
-		datain := <-i.recv
+func (i *icmpv6) parse_packet(datain []byte) {
+	var response []byte
+	var err error
 
-		if i.tun.iface.IsTAP() {
-			// TAP mode
-			response, err := i.parse_packet_tap(datain)
-			if err != nil {
-				i.tun.core.log.Printf("Error from icmpv6.parse_packet_tap: %v", err)
-				continue
-			}
-			if response != nil {
-				i.tun.iface.Write(response)
-			}
-		} else {
-			// TUN mode
-			response, err := i.parse_packet_tun(datain)
-			if err != nil {
-				i.tun.core.log.Printf("Error from icmpv6.parse_packet_tun: %v", err)
-				continue
-			}
-			if response != nil {
-				i.tun.iface.Write(response)
-			}
-		}
+	if i.tun.iface.IsTAP() {
+		response, err = i.parse_packet_tap(datain)
+	} else {
+		response, err = i.parse_packet_tun(datain)
+	}
+	if err != nil {
+		i.tun.core.log.Printf("ICMPv6 error: %v", err)
+		return
+	}
+	if response != nil {
+		i.tun.iface.Write(response)
 	}
 }
 
diff --git a/src/yggdrasil/tun.go b/src/yggdrasil/tun.go
index b1d96d9..dc2c673 100644
--- a/src/yggdrasil/tun.go
+++ b/src/yggdrasil/tun.go
@@ -79,7 +79,12 @@ func (tun *tunDevice) read() error {
 			// Found an ICMPv6 packet
 			b := make([]byte, n)
 			copy(b, buf)
-			tun.icmpv6.recv <- b
+			// tun.icmpv6.recv <- b
+			if tun.iface.IsTAP() {
+				go tun.icmpv6.parse_packet_tap(b)
+			} else {
+				go tun.icmpv6.parse_packet_tun(b)
+			}
 		}
 		packet := append(util_getBytes(), buf[o:n]...)
 		tun.send <- packet