From 10157483f9bd36a5b02ee20569c908f6d8d75914 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 17:35:02 +0000
Subject: [PATCH 1/9] Move tunDevice into router

---
 src/yggdrasil/admin.go   | 18 +++++++++---------
 src/yggdrasil/core.go    | 10 ++++------
 src/yggdrasil/router.go  | 14 ++++++++++----
 src/yggdrasil/session.go |  2 +-
 4 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/src/yggdrasil/admin.go b/src/yggdrasil/admin.go
index 266d5a8..e80ca39 100644
--- a/src/yggdrasil/admin.go
+++ b/src/yggdrasil/admin.go
@@ -160,9 +160,9 @@ func (a *admin) init(c *Core, listenaddr string) {
 		}()
 
 		return admin_info{
-			a.core.tun.iface.Name(): admin_info{
-				"tap_mode": a.core.tun.iface.IsTAP(),
-				"mtu":      a.core.tun.mtu,
+			a.core.router.tun.iface.Name(): admin_info{
+				"tap_mode": a.core.router.tun.iface.IsTAP(),
+				"mtu":      a.core.router.tun.mtu,
 			},
 		}, nil
 	})
@@ -185,8 +185,8 @@ func (a *admin) init(c *Core, listenaddr string) {
 			return admin_info{}, errors.New("Failed to configure adapter")
 		} else {
 			return admin_info{
-				a.core.tun.iface.Name(): admin_info{
-					"tap_mode": a.core.tun.iface.IsTAP(),
+				a.core.router.tun.iface.Name(): admin_info{
+					"tap_mode": a.core.router.tun.iface.IsTAP(),
 					"mtu":      ifmtu,
 				},
 			}, nil
@@ -539,12 +539,12 @@ func (a *admin) removePeer(p string) error {
 // startTunWithMTU creates the tun/tap device, sets its address, and sets the MTU to the provided value.
 func (a *admin) startTunWithMTU(ifname string, iftapmode bool, ifmtu int) error {
 	// Close the TUN first if open
-	_ = a.core.tun.close()
+	_ = a.core.router.tun.close()
 	// Then reconfigure and start it
 	addr := a.core.router.addr
 	straddr := fmt.Sprintf("%s/%v", net.IP(addr[:]).String(), 8*len(address_prefix)-1)
 	if ifname != "none" {
-		err := a.core.tun.setup(ifname, iftapmode, straddr, ifmtu)
+		err := a.core.router.tun.setup(ifname, iftapmode, straddr, ifmtu)
 		if err != nil {
 			return err
 		}
@@ -559,9 +559,9 @@ func (a *admin) startTunWithMTU(ifname string, iftapmode bool, ifmtu int) error
 			a.core.sessions.sendPingPong(sinfo, false)
 		}
 		// Aaaaand... go!
-		go a.core.tun.read()
+		go a.core.router.tun.read()
 	}
-	go a.core.tun.write()
+	go a.core.router.tun.write()
 	return nil
 }
 
diff --git a/src/yggdrasil/core.go b/src/yggdrasil/core.go
index 5ab91a7..13609ce 100644
--- a/src/yggdrasil/core.go
+++ b/src/yggdrasil/core.go
@@ -28,7 +28,6 @@ type Core struct {
 	sessions    sessions
 	router      router
 	dht         dht
-	tun         tunDevice
 	admin       admin
 	searches    searches
 	multicast   multicast
@@ -59,7 +58,6 @@ func (c *Core) init(bpub *boxPubKey,
 	c.peers.init(c)
 	c.router.init(c)
 	c.switchTable.init(c, c.sigPub) // TODO move before peers? before router?
-	c.tun.init(c)
 }
 
 // Get the current build name. This is usually injected if built from git,
@@ -188,7 +186,7 @@ func (c *Core) Start(nc *config.NodeConfig, log *log.Logger) error {
 	}
 
 	ip := net.IP(c.router.addr[:]).String()
-	if err := c.tun.start(nc.IfName, nc.IfTAPMode, fmt.Sprintf("%s/%d", ip, 8*len(address_prefix)-1), nc.IfMTU); err != nil {
+	if err := c.router.tun.start(nc.IfName, nc.IfTAPMode, fmt.Sprintf("%s/%d", ip, 8*len(address_prefix)-1), nc.IfMTU); err != nil {
 		c.log.Println("Failed to start TUN/TAP")
 		return err
 	}
@@ -200,7 +198,7 @@ func (c *Core) Start(nc *config.NodeConfig, log *log.Logger) error {
 // Stops the Yggdrasil node.
 func (c *Core) Stop() {
 	c.log.Println("Stopping...")
-	c.tun.close()
+	c.router.tun.close()
 	c.admin.close()
 }
 
@@ -293,10 +291,10 @@ func (c *Core) GetTUNDefaultIfTAPMode() bool {
 
 // Gets the current TUN/TAP interface name.
 func (c *Core) GetTUNIfName() string {
-	return c.tun.iface.Name()
+	return c.router.tun.iface.Name()
 }
 
 // Gets the current TUN/TAP interface MTU.
 func (c *Core) GetTUNIfMTU() int {
-	return c.tun.mtu
+	return c.router.tun.mtu
 }
diff --git a/src/yggdrasil/router.go b/src/yggdrasil/router.go
index b482476..eab18b1 100644
--- a/src/yggdrasil/router.go
+++ b/src/yggdrasil/router.go
@@ -30,6 +30,10 @@ import (
 	"golang.org/x/net/ipv6"
 )
 
+type adapter struct {
+	tunDevice
+}
+
 // The router struct has channels to/from the tun/tap device and a self peer (0), which is how messages are passed between this node and the peers/switch layer.
 // The router's mainLoop goroutine is responsible for managing all information related to the dht, searches, and crypto sessions.
 type router struct {
@@ -39,6 +43,7 @@ type router struct {
 	in        <-chan []byte          // packets we received from the network, link to peer's "out"
 	out       func([]byte)           // packets we're sending to the network, link to peer's "in"
 	toRecv    chan router_recvPacket // packets to handle via recvPacket()
+	tun       tunDevice              // TUN/TAP adapter
 	recv      chan<- []byte          // place where the tun pulls received packets from
 	send      <-chan []byte          // place where the tun puts outgoing packets
 	reset     chan struct{}          // signal that coords changed (re-init sessions/dht)
@@ -75,11 +80,12 @@ func (r *router) init(core *Core) {
 	send := make(chan []byte, 32)
 	r.recv = recv
 	r.send = send
-	r.core.tun.recv = recv
-	r.core.tun.send = send
+	r.tun.recv = recv
+	r.tun.send = send
 	r.reset = make(chan struct{}, 1)
 	r.admin = make(chan func(), 32)
 	r.cryptokey.init(r.core)
+	r.tun.init(r.core)
 	// go r.mainLoop()
 }
 
@@ -279,7 +285,7 @@ func (r *router) sendPacket(bs []byte) {
 			}
 
 			// Create the ICMPv6 response from it
-			icmpv6Buf, err := r.core.tun.icmpv6.create_icmpv6_tun(
+			icmpv6Buf, err := r.tun.icmpv6.create_icmpv6_tun(
 				bs[8:24], bs[24:40],
 				ipv6.ICMPTypeDestinationUnreachable, 1, ptb)
 			if err == nil {
@@ -304,7 +310,7 @@ func (r *router) sendPacket(bs []byte) {
 			}
 
 			// Create the ICMPv6 response from it
-			icmpv6Buf, err := r.core.tun.icmpv6.create_icmpv6_tun(
+			icmpv6Buf, err := r.tun.icmpv6.create_icmpv6_tun(
 				bs[8:24], bs[24:40],
 				ipv6.ICMPTypePacketTooBig, 0, ptb)
 			if err == nil {
diff --git a/src/yggdrasil/session.go b/src/yggdrasil/session.go
index 92ae262..4f2bedf 100644
--- a/src/yggdrasil/session.go
+++ b/src/yggdrasil/session.go
@@ -273,7 +273,7 @@ func (ss *sessions) createSession(theirPermKey *boxPubKey) *sessionInfo {
 	sinfo.mySesPriv = *priv
 	sinfo.myNonce = *newBoxNonce()
 	sinfo.theirMTU = 1280
-	sinfo.myMTU = uint16(ss.core.tun.mtu)
+	sinfo.myMTU = uint16(ss.core.router.tun.mtu)
 	now := time.Now()
 	sinfo.time = now
 	sinfo.mtuTime = now

From ccf6ce07a444f8acdc3cba86db16ff89c59d1c43 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 17:49:42 +0000
Subject: [PATCH 2/9] Fix Peers and InterfacePeers when not in correct format

---
 cmd/yggdrasil/main.go | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/cmd/yggdrasil/main.go b/cmd/yggdrasil/main.go
index 5b75690..ec8c712 100644
--- a/cmd/yggdrasil/main.go
+++ b/cmd/yggdrasil/main.go
@@ -12,6 +12,7 @@ import (
 	"os"
 	"os/signal"
 	"regexp"
+	"strings"
 	"syscall"
 	"time"
 
@@ -188,6 +189,25 @@ func main() {
 				}
 			}
 		}
+		// Check to see if the peers are in a parsable format, if not then default
+		// them to the TCP scheme
+		for index, peer := range dat["Peers"].([]interface{}) {
+			uri := peer.(string)
+			if strings.HasPrefix(uri, "tcp://") || strings.HasPrefix(uri, "socks://") {
+				continue
+			}
+			(dat["Peers"].([]interface{}))[index] = "tcp://" + uri
+		}
+		// Now do the same with the interface peers
+		for intf, peers := range dat["InterfacePeers"].(map[string]interface{}) {
+			for index, peer := range peers.([]interface{}) {
+				uri := peer.(string)
+				if strings.HasPrefix(uri, "tcp://") || strings.HasPrefix(uri, "socks://") {
+					continue
+				}
+				((dat["InterfacePeers"].(map[string]interface{}))[intf]).([]interface{})[index] = "tcp://" + uri
+			}
+		}
 		// Overlay our newly mapped configuration onto the autoconf node config that
 		// we generated above.
 		if err = mapstructure.Decode(dat, &cfg); err != nil {

From 3ca5f10733fe86241fb185dcac0291bd5d30df94 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 17:52:54 +0000
Subject: [PATCH 3/9] Don't try to correct peers with no schemes in addPeer

---
 src/yggdrasil/admin.go | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/src/yggdrasil/admin.go b/src/yggdrasil/admin.go
index e80ca39..577b6ef 100644
--- a/src/yggdrasil/admin.go
+++ b/src/yggdrasil/admin.go
@@ -515,13 +515,7 @@ func (a *admin) addPeer(addr string, sintf string) error {
 			return errors.New("invalid peer: " + addr)
 		}
 	} else {
-		// no url scheme provided
-		addr = strings.ToLower(addr)
-		if strings.HasPrefix(addr, "tcp:") {
-			addr = addr[4:]
-		}
-		a.core.tcp.connect(addr, "")
-		return nil
+		return errors.New("invalid peer: " + addr)
 	}
 	return nil
 }

From 1a7df477b011aafeb5425c16ee84087128c9fa54 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 17:55:07 +0000
Subject: [PATCH 4/9] Also correct tcp: into tcp://

---
 cmd/yggdrasil/main.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/cmd/yggdrasil/main.go b/cmd/yggdrasil/main.go
index ec8c712..ee5375b 100644
--- a/cmd/yggdrasil/main.go
+++ b/cmd/yggdrasil/main.go
@@ -196,6 +196,9 @@ func main() {
 			if strings.HasPrefix(uri, "tcp://") || strings.HasPrefix(uri, "socks://") {
 				continue
 			}
+			if strings.HasPrefix(uri, "tcp:") {
+				uri = uri[4:]
+			}
 			(dat["Peers"].([]interface{}))[index] = "tcp://" + uri
 		}
 		// Now do the same with the interface peers
@@ -205,6 +208,9 @@ func main() {
 				if strings.HasPrefix(uri, "tcp://") || strings.HasPrefix(uri, "socks://") {
 					continue
 				}
+				if strings.HasPrefix(uri, "tcp:") {
+					uri = uri[4:]
+				}
 				((dat["InterfacePeers"].(map[string]interface{}))[intf]).([]interface{})[index] = "tcp://" + uri
 			}
 		}

From 9eaa2566c1d032d5769574f5825352568374c79f Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 18:08:13 +0000
Subject: [PATCH 5/9] Parameterise tun.init

---
 src/yggdrasil/router.go | 5 +----
 src/yggdrasil/tun.go    | 4 +++-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/yggdrasil/router.go b/src/yggdrasil/router.go
index eab18b1..3b6d204 100644
--- a/src/yggdrasil/router.go
+++ b/src/yggdrasil/router.go
@@ -80,13 +80,10 @@ func (r *router) init(core *Core) {
 	send := make(chan []byte, 32)
 	r.recv = recv
 	r.send = send
-	r.tun.recv = recv
-	r.tun.send = send
 	r.reset = make(chan struct{}, 1)
 	r.admin = make(chan func(), 32)
 	r.cryptokey.init(r.core)
-	r.tun.init(r.core)
-	// go r.mainLoop()
+	r.tun.init(r.core, send, recv)
 }
 
 // Starts the mainLoop goroutine.
diff --git a/src/yggdrasil/tun.go b/src/yggdrasil/tun.go
index e462502..85204da 100644
--- a/src/yggdrasil/tun.go
+++ b/src/yggdrasil/tun.go
@@ -36,9 +36,11 @@ func getSupportedMTU(mtu int) int {
 }
 
 // Initialises the TUN/TAP adapter.
-func (tun *tunDevice) init(core *Core) {
+func (tun *tunDevice) init(core *Core, send chan<- []byte, recv <-chan []byte) {
 	tun.core = core
 	tun.icmpv6.init(tun)
+	tun.send = send
+	tun.recv = recv
 }
 
 // Starts the setup process for the TUN/TAP adapter, and if successful, starts

From 2a38ad07cde19d911ff2ee4a41fbb3c346f8f82f Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 18:08:40 +0000
Subject: [PATCH 6/9] Don't send ICMPv6 back when tun disabled

---
 src/yggdrasil/router.go | 19 -------------------
 1 file changed, 19 deletions(-)

diff --git a/src/yggdrasil/router.go b/src/yggdrasil/router.go
index 3b6d204..d016d1c 100644
--- a/src/yggdrasil/router.go
+++ b/src/yggdrasil/router.go
@@ -270,25 +270,6 @@ func (r *router) sendPacket(bs []byte) {
 		// Drop packets if the session MTU is 0 - this means that one or other
 		// side probably has their TUN adapter disabled
 		if sinfo.getMTU() == 0 {
-			// Get the size of the oversized payload, up to a max of 900 bytes
-			window := 900
-			if len(bs) < window {
-				window = len(bs)
-			}
-
-			// Create the Destination Unreachable response
-			ptb := &icmp.DstUnreach{
-				Data: bs[:window],
-			}
-
-			// Create the ICMPv6 response from it
-			icmpv6Buf, err := r.tun.icmpv6.create_icmpv6_tun(
-				bs[8:24], bs[24:40],
-				ipv6.ICMPTypeDestinationUnreachable, 1, ptb)
-			if err == nil {
-				r.recv <- icmpv6Buf
-			}
-
 			// Don't continue - drop the packet
 			return
 		}

From f28360ce4d5d56fe3965bfebe624a0077e53fc6c Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 18:10:39 +0000
Subject: [PATCH 7/9] Fix debug builds (foiled by debug builds every time)

---
 src/yggdrasil/debug.go | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/yggdrasil/debug.go b/src/yggdrasil/debug.go
index e463518..e5bceee 100644
--- a/src/yggdrasil/debug.go
+++ b/src/yggdrasil/debug.go
@@ -68,11 +68,11 @@ func (c *Core) DEBUG_getEncryptionPublicKey() boxPubKey {
 }
 
 func (c *Core) DEBUG_getSend() chan<- []byte {
-	return c.tun.send
+	return c.router.tun.send
 }
 
 func (c *Core) DEBUG_getRecv() <-chan []byte {
-	return c.tun.recv
+	return c.router.tun.recv
 }
 
 // Peer
@@ -304,18 +304,18 @@ func (c *Core) DEBUG_startTunWithMTU(ifname string, iftapmode bool, mtu int) {
 	addr := c.DEBUG_getAddr()
 	straddr := fmt.Sprintf("%s/%v", net.IP(addr[:]).String(), 8*len(address_prefix))
 	if ifname != "none" {
-		err := c.tun.setup(ifname, iftapmode, straddr, mtu)
+		err := c.router.tun.setup(ifname, iftapmode, straddr, mtu)
 		if err != nil {
 			panic(err)
 		}
-		c.log.Println("Setup TUN/TAP:", c.tun.iface.Name(), straddr)
-		go func() { panic(c.tun.read()) }()
+		c.log.Println("Setup TUN/TAP:", c.router.tun.iface.Name(), straddr)
+		go func() { panic(c.router.tun.read()) }()
 	}
-	go func() { panic(c.tun.write()) }()
+	go func() { panic(c.router.tun.write()) }()
 }
 
 func (c *Core) DEBUG_stopTun() {
-	c.tun.close()
+	c.router.tun.close()
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -546,7 +546,7 @@ func DEBUG_simLinkPeers(p, q *peer) {
 }
 
 func (c *Core) DEBUG_simFixMTU() {
-	c.tun.mtu = 65535
+	c.router.tun.mtu = 65535
 }
 
 ////////////////////////////////////////////////////////////////////////////////

From 8045cb4dc3c5e165c848ce0ab4fe7c71bd99d615 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 18:21:08 +0000
Subject: [PATCH 8/9] Define generic adapter type, rename tunDevice to
 tunAdapter

---
 src/yggdrasil/icmpv6.go      |  4 ++--
 src/yggdrasil/router.go      |  7 +++++--
 src/yggdrasil/tun.go         | 16 +++++++---------
 src/yggdrasil/tun_bsd.go     |  4 ++--
 src/yggdrasil/tun_darwin.go  |  4 ++--
 src/yggdrasil/tun_linux.go   |  4 ++--
 src/yggdrasil/tun_other.go   |  4 ++--
 src/yggdrasil/tun_windows.go |  6 +++---
 8 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/src/yggdrasil/icmpv6.go b/src/yggdrasil/icmpv6.go
index 957b192..6e9a265 100644
--- a/src/yggdrasil/icmpv6.go
+++ b/src/yggdrasil/icmpv6.go
@@ -24,7 +24,7 @@ type macAddress [6]byte
 const len_ETHER = 14
 
 type icmpv6 struct {
-	tun      *tunDevice
+	tun      *tunAdapter
 	mylladdr net.IP
 	mymac    macAddress
 	peermacs map[address]neighbor
@@ -57,7 +57,7 @@ func ipv6Header_Marshal(h *ipv6.Header) ([]byte, error) {
 // Initialises the ICMPv6 module by assigning our link-local IPv6 address and
 // our MAC address. ICMPv6 messages will always appear to originate from these
 // addresses.
-func (i *icmpv6) init(t *tunDevice) {
+func (i *icmpv6) init(t *tunAdapter) {
 	i.tun = t
 	i.peermacs = make(map[address]neighbor)
 
diff --git a/src/yggdrasil/router.go b/src/yggdrasil/router.go
index d016d1c..dd9f05d 100644
--- a/src/yggdrasil/router.go
+++ b/src/yggdrasil/router.go
@@ -31,7 +31,9 @@ import (
 )
 
 type adapter struct {
-	tunDevice
+	core *Core
+	send chan<- []byte
+	recv <-chan []byte
 }
 
 // The router struct has channels to/from the tun/tap device and a self peer (0), which is how messages are passed between this node and the peers/switch layer.
@@ -43,7 +45,8 @@ type router struct {
 	in        <-chan []byte          // packets we received from the network, link to peer's "out"
 	out       func([]byte)           // packets we're sending to the network, link to peer's "in"
 	toRecv    chan router_recvPacket // packets to handle via recvPacket()
-	tun       tunDevice              // TUN/TAP adapter
+	tun       tunAdapter              // TUN/TAP adapter
+	adapters  []adapter              // Other adapters
 	recv      chan<- []byte          // place where the tun pulls received packets from
 	send      <-chan []byte          // place where the tun puts outgoing packets
 	reset     chan struct{}          // signal that coords changed (re-init sessions/dht)
diff --git a/src/yggdrasil/tun.go b/src/yggdrasil/tun.go
index 85204da..223092e 100644
--- a/src/yggdrasil/tun.go
+++ b/src/yggdrasil/tun.go
@@ -17,11 +17,9 @@ const tun_IPv6_HEADER_LENGTH = 40
 const tun_ETHER_HEADER_LENGTH = 14
 
 // Represents a running TUN/TAP interface.
-type tunDevice struct {
-	core   *Core
+type tunAdapter struct {
+	adapter
 	icmpv6 icmpv6
-	send   chan<- []byte
-	recv   <-chan []byte
 	mtu    int
 	iface  *water.Interface
 }
@@ -36,7 +34,7 @@ func getSupportedMTU(mtu int) int {
 }
 
 // Initialises the TUN/TAP adapter.
-func (tun *tunDevice) init(core *Core, send chan<- []byte, recv <-chan []byte) {
+func (tun *tunAdapter) init(core *Core, send chan<- []byte, recv <-chan []byte) {
 	tun.core = core
 	tun.icmpv6.init(tun)
 	tun.send = send
@@ -45,7 +43,7 @@ func (tun *tunDevice) init(core *Core, send chan<- []byte, recv <-chan []byte) {
 
 // Starts the setup process for the TUN/TAP adapter, and if successful, starts
 // the read/write goroutines to handle packets on that interface.
-func (tun *tunDevice) start(ifname string, iftapmode bool, addr string, mtu int) error {
+func (tun *tunAdapter) start(ifname string, iftapmode bool, addr string, mtu int) error {
 	if ifname == "none" {
 		return nil
 	}
@@ -77,7 +75,7 @@ func (tun *tunDevice) start(ifname string, iftapmode bool, addr string, mtu int)
 // Writes a packet to the TUN/TAP adapter. If the adapter is running in TAP
 // mode then additional ethernet encapsulation is added for the benefit of the
 // host operating system.
-func (tun *tunDevice) write() error {
+func (tun *tunAdapter) write() error {
 	for {
 		data := <-tun.recv
 		if tun.iface == nil {
@@ -166,7 +164,7 @@ func (tun *tunDevice) write() error {
 // is running in TAP mode then the ethernet headers will automatically be
 // processed and stripped if necessary. If an ICMPv6 packet is found, then
 // the relevant helper functions in icmpv6.go are called.
-func (tun *tunDevice) read() error {
+func (tun *tunAdapter) read() error {
 	mtu := tun.mtu
 	if tun.iface.IsTAP() {
 		mtu += tun_ETHER_HEADER_LENGTH
@@ -203,7 +201,7 @@ func (tun *tunDevice) read() error {
 // Closes the TUN/TAP adapter. This is only usually called when the Yggdrasil
 // process stops. Typically this operation will happen quickly, but on macOS
 // it can block until a read operation is completed.
-func (tun *tunDevice) close() error {
+func (tun *tunAdapter) close() error {
 	if tun.iface == nil {
 		return nil
 	}
diff --git a/src/yggdrasil/tun_bsd.go b/src/yggdrasil/tun_bsd.go
index ca5eaea..620c79d 100644
--- a/src/yggdrasil/tun_bsd.go
+++ b/src/yggdrasil/tun_bsd.go
@@ -77,7 +77,7 @@ type in6_ifreq_lifetime struct {
 // a system socket and making syscalls to the kernel. This is not refined though
 // and often doesn't work (if at all), therefore if a call fails, it resorts
 // to calling "ifconfig" instead.
-func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int) error {
+func (tun *tunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
 	var config water.Config
 	if ifname[:4] == "auto" {
 		ifname = "/dev/tap0"
@@ -103,7 +103,7 @@ func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int)
 	return tun.setupAddress(addr)
 }
 
-func (tun *tunDevice) setupAddress(addr string) error {
+func (tun *tunAdapter) setupAddress(addr string) error {
 	var sfd int
 	var err error
 
diff --git a/src/yggdrasil/tun_darwin.go b/src/yggdrasil/tun_darwin.go
index e49ab52..943468e 100644
--- a/src/yggdrasil/tun_darwin.go
+++ b/src/yggdrasil/tun_darwin.go
@@ -14,7 +14,7 @@ import (
 )
 
 // Configures the "utun" adapter with the correct IPv6 address and MTU.
-func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int) error {
+func (tun *tunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
 	if iftapmode {
 		tun.core.log.Printf("TAP mode is not supported on this platform, defaulting to TUN")
 	}
@@ -62,7 +62,7 @@ type ifreq struct {
 
 // Sets the IPv6 address of the utun adapter. On Darwin/macOS this is done using
 // a system socket and making direct syscalls to the kernel.
-func (tun *tunDevice) setupAddress(addr string) error {
+func (tun *tunAdapter) setupAddress(addr string) error {
 	var fd int
 	var err error
 
diff --git a/src/yggdrasil/tun_linux.go b/src/yggdrasil/tun_linux.go
index aa9e791..7a7c9cb 100644
--- a/src/yggdrasil/tun_linux.go
+++ b/src/yggdrasil/tun_linux.go
@@ -13,7 +13,7 @@ import (
 )
 
 // Configures the TAP adapter with the correct IPv6 address and MTU.
-func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int) error {
+func (tun *tunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
 	var config water.Config
 	if iftapmode {
 		config = water.Config{DeviceType: water.TAP}
@@ -48,7 +48,7 @@ func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int)
 // is used to do this, so there is not a hard requirement on "ip" or "ifconfig"
 // to exist on the system, but this will fail if Netlink is not present in the
 // kernel (it nearly always is).
-func (tun *tunDevice) setupAddress(addr string) error {
+func (tun *tunAdapter) setupAddress(addr string) error {
 	// Set address
 	var netIF *net.Interface
 	ifces, err := net.Interfaces()
diff --git a/src/yggdrasil/tun_other.go b/src/yggdrasil/tun_other.go
index 1a3721a..625f9cd 100644
--- a/src/yggdrasil/tun_other.go
+++ b/src/yggdrasil/tun_other.go
@@ -9,7 +9,7 @@ import water "github.com/yggdrasil-network/water"
 
 // Creates the TUN/TAP adapter, if supported by the Water library. Note that
 // no guarantees are made at this point on an unsupported platform.
-func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int) error {
+func (tun *tunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
 	var config water.Config
 	if iftapmode {
 		config = water.Config{DeviceType: water.TAP}
@@ -27,7 +27,7 @@ func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int)
 
 // We don't know how to set the IPv6 address on an unknown platform, therefore
 // write about it to stdout and don't try to do anything further.
-func (tun *tunDevice) setupAddress(addr string) error {
+func (tun *tunAdapter) setupAddress(addr string) error {
 	tun.core.log.Println("Platform not supported, you must set the address of", tun.iface.Name(), "to", addr)
 	return nil
 }
diff --git a/src/yggdrasil/tun_windows.go b/src/yggdrasil/tun_windows.go
index d3420df..150a976 100644
--- a/src/yggdrasil/tun_windows.go
+++ b/src/yggdrasil/tun_windows.go
@@ -13,7 +13,7 @@ import (
 // Configures the TAP adapter with the correct IPv6 address and MTU. On Windows
 // we don't make use of a direct operating system API to do this - we instead
 // delegate the hard work to "netsh".
-func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int) error {
+func (tun *tunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
 	if !iftapmode {
 		tun.core.log.Printf("TUN mode is not supported on this platform, defaulting to TAP")
 	}
@@ -65,7 +65,7 @@ func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int)
 }
 
 // Sets the MTU of the TAP adapter.
-func (tun *tunDevice) setupMTU(mtu int) error {
+func (tun *tunAdapter) setupMTU(mtu int) error {
 	// Set MTU
 	cmd := exec.Command("netsh", "interface", "ipv6", "set", "subinterface",
 		fmt.Sprintf("interface=%s", tun.iface.Name()),
@@ -82,7 +82,7 @@ func (tun *tunDevice) setupMTU(mtu int) error {
 }
 
 // Sets the IPv6 address of the TAP adapter.
-func (tun *tunDevice) setupAddress(addr string) error {
+func (tun *tunAdapter) setupAddress(addr string) error {
 	// Set address
 	cmd := exec.Command("netsh", "interface", "ipv6", "add", "address",
 		fmt.Sprintf("interface=%s", tun.iface.Name()),

From f9dc300787a3a871144585b813610d6776dd6fc0 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 14 Dec 2018 18:29:00 +0000
Subject: [PATCH 9/9] Define Adapter base type/interface

---
 src/yggdrasil/adapter.go | 25 +++++++++++++++++++++++++
 src/yggdrasil/router.go  | 10 ++--------
 src/yggdrasil/tun.go     |  6 ++----
 3 files changed, 29 insertions(+), 12 deletions(-)
 create mode 100644 src/yggdrasil/adapter.go

diff --git a/src/yggdrasil/adapter.go b/src/yggdrasil/adapter.go
new file mode 100644
index 0000000..4a43209
--- /dev/null
+++ b/src/yggdrasil/adapter.go
@@ -0,0 +1,25 @@
+package yggdrasil
+
+// Defines the minimum required functions for an adapter type.
+type AdapterInterface interface {
+	init(core *Core, send chan<- []byte, recv <-chan []byte)
+	read() error
+	write() error
+	close() error
+}
+
+// Defines the minimum required struct members for an adapter type (this is
+// now the base type for tunAdapter in tun.go)
+type Adapter struct {
+	AdapterInterface
+	core *Core
+	send chan<- []byte
+	recv <-chan []byte
+}
+
+// Initialises the adapter.
+func (adapter *Adapter) init(core *Core, send chan<- []byte, recv <-chan []byte) {
+	adapter.core = core
+	adapter.send = send
+	adapter.recv = recv
+}
diff --git a/src/yggdrasil/router.go b/src/yggdrasil/router.go
index dd9f05d..62480bc 100644
--- a/src/yggdrasil/router.go
+++ b/src/yggdrasil/router.go
@@ -30,12 +30,6 @@ import (
 	"golang.org/x/net/ipv6"
 )
 
-type adapter struct {
-	core *Core
-	send chan<- []byte
-	recv <-chan []byte
-}
-
 // The router struct has channels to/from the tun/tap device and a self peer (0), which is how messages are passed between this node and the peers/switch layer.
 // The router's mainLoop goroutine is responsible for managing all information related to the dht, searches, and crypto sessions.
 type router struct {
@@ -45,8 +39,8 @@ type router struct {
 	in        <-chan []byte          // packets we received from the network, link to peer's "out"
 	out       func([]byte)           // packets we're sending to the network, link to peer's "in"
 	toRecv    chan router_recvPacket // packets to handle via recvPacket()
-	tun       tunAdapter              // TUN/TAP adapter
-	adapters  []adapter              // Other adapters
+	tun       tunAdapter             // TUN/TAP adapter
+	adapters  []Adapter              // Other adapters
 	recv      chan<- []byte          // place where the tun pulls received packets from
 	send      <-chan []byte          // place where the tun puts outgoing packets
 	reset     chan struct{}          // signal that coords changed (re-init sessions/dht)
diff --git a/src/yggdrasil/tun.go b/src/yggdrasil/tun.go
index 223092e..26d32c0 100644
--- a/src/yggdrasil/tun.go
+++ b/src/yggdrasil/tun.go
@@ -18,7 +18,7 @@ const tun_ETHER_HEADER_LENGTH = 14
 
 // Represents a running TUN/TAP interface.
 type tunAdapter struct {
-	adapter
+	Adapter
 	icmpv6 icmpv6
 	mtu    int
 	iface  *water.Interface
@@ -35,10 +35,8 @@ func getSupportedMTU(mtu int) int {
 
 // Initialises the TUN/TAP adapter.
 func (tun *tunAdapter) init(core *Core, send chan<- []byte, recv <-chan []byte) {
-	tun.core = core
+	tun.Adapter.init(core, send, recv)
 	tun.icmpv6.init(tun)
-	tun.send = send
-	tun.recv = recv
 }
 
 // Starts the setup process for the TUN/TAP adapter, and if successful, starts