global: begin modularization

34 files changed, 6482 insertions, 0 deletions

diff --git a/device/allowedips.go b/device/allowedips.go
new file mode 100644
index 0000000..efc27c0
--- /dev/null
+++ b/device/allowedips.go
@@ -0,0 +1,251 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"errors"
+	"math/bits"
+	"net"
+	"sync"
+	"unsafe"
+)
+
+type trieEntry struct {
+	cidr  uint
+	child [2]*trieEntry
+	bits  net.IP
+	peer  *Peer
+
+	// index of "branching" bit
+
+	bit_at_byte  uint
+	bit_at_shift uint
+}
+
+func isLittleEndian() bool {
+	one := uint32(1)
+	return *(*byte)(unsafe.Pointer(&one)) != 0
+}
+
+func swapU32(i uint32) uint32 {
+	if !isLittleEndian() {
+		return i
+	}
+
+	return bits.ReverseBytes32(i)
+}
+
+func swapU64(i uint64) uint64 {
+	if !isLittleEndian() {
+		return i
+	}
+
+	return bits.ReverseBytes64(i)
+}
+
+func commonBits(ip1 net.IP, ip2 net.IP) uint {
+	size := len(ip1)
+	if size == net.IPv4len {
+		a := (*uint32)(unsafe.Pointer(&ip1[0]))
+		b := (*uint32)(unsafe.Pointer(&ip2[0]))
+		x := *a ^ *b
+		return uint(bits.LeadingZeros32(swapU32(x)))
+	} else if size == net.IPv6len {
+		a := (*uint64)(unsafe.Pointer(&ip1[0]))
+		b := (*uint64)(unsafe.Pointer(&ip2[0]))
+		x := *a ^ *b
+		if x != 0 {
+			return uint(bits.LeadingZeros64(swapU64(x)))
+		}
+		a = (*uint64)(unsafe.Pointer(&ip1[8]))
+		b = (*uint64)(unsafe.Pointer(&ip2[8]))
+		x = *a ^ *b
+		return 64 + uint(bits.LeadingZeros64(swapU64(x)))
+	} else {
+		panic("Wrong size bit string")
+	}
+}
+
+func (node *trieEntry) removeByPeer(p *Peer) *trieEntry {
+	if node == nil {
+		return node
+	}
+
+	// walk recursively
+
+	node.child[0] = node.child[0].removeByPeer(p)
+	node.child[1] = node.child[1].removeByPeer(p)
+
+	if node.peer != p {
+		return node
+	}
+
+	// remove peer & merge
+
+	node.peer = nil
+	if node.child[0] == nil {
+		return node.child[1]
+	}
+	return node.child[0]
+}
+
+func (node *trieEntry) choose(ip net.IP) byte {
+	return (ip[node.bit_at_byte] >> node.bit_at_shift) & 1
+}
+
+func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
+
+	// at leaf
+
+	if node == nil {
+		return &trieEntry{
+			bits:         ip,
+			peer:         peer,
+			cidr:         cidr,
+			bit_at_byte:  cidr / 8,
+			bit_at_shift: 7 - (cidr % 8),
+		}
+	}
+
+	// traverse deeper
+
+	common := commonBits(node.bits, ip)
+	if node.cidr <= cidr && common >= node.cidr {
+		if node.cidr == cidr {
+			node.peer = peer
+			return node
+		}
+		bit := node.choose(ip)
+		node.child[bit] = node.child[bit].insert(ip, cidr, peer)
+		return node
+	}
+
+	// split node
+
+	newNode := &trieEntry{
+		bits:         ip,
+		peer:         peer,
+		cidr:         cidr,
+		bit_at_byte:  cidr / 8,
+		bit_at_shift: 7 - (cidr % 8),
+	}
+
+	cidr = min(cidr, common)
+
+	// check for shorter prefix
+
+	if newNode.cidr == cidr {
+		bit := newNode.choose(node.bits)
+		newNode.child[bit] = node
+		return newNode
+	}
+
+	// create new parent for node & newNode
+
+	parent := &trieEntry{
+		bits:         ip,
+		peer:         nil,
+		cidr:         cidr,
+		bit_at_byte:  cidr / 8,
+		bit_at_shift: 7 - (cidr % 8),
+	}
+
+	bit := parent.choose(ip)
+	parent.child[bit] = newNode
+	parent.child[bit^1] = node
+
+	return parent
+}
+
+func (node *trieEntry) lookup(ip net.IP) *Peer {
+	var found *Peer
+	size := uint(len(ip))
+	for node != nil && commonBits(node.bits, ip) >= node.cidr {
+		if node.peer != nil {
+			found = node.peer
+		}
+		if node.bit_at_byte == size {
+			break
+		}
+		bit := node.choose(ip)
+		node = node.child[bit]
+	}
+	return found
+}
+
+func (node *trieEntry) entriesForPeer(p *Peer, results []net.IPNet) []net.IPNet {
+	if node == nil {
+		return results
+	}
+	if node.peer == p {
+		mask := net.CIDRMask(int(node.cidr), len(node.bits)*8)
+		results = append(results, net.IPNet{
+			Mask: mask,
+			IP:   node.bits.Mask(mask),
+		})
+	}
+	results = node.child[0].entriesForPeer(p, results)
+	results = node.child[1].entriesForPeer(p, results)
+	return results
+}
+
+type AllowedIPs struct {
+	IPv4  *trieEntry
+	IPv6  *trieEntry
+	mutex sync.RWMutex
+}
+
+func (table *AllowedIPs) EntriesForPeer(peer *Peer) []net.IPNet {
+	table.mutex.RLock()
+	defer table.mutex.RUnlock()
+
+	allowed := make([]net.IPNet, 0, 10)
+	allowed = table.IPv4.entriesForPeer(peer, allowed)
+	allowed = table.IPv6.entriesForPeer(peer, allowed)
+	return allowed
+}
+
+func (table *AllowedIPs) Reset() {
+	table.mutex.Lock()
+	defer table.mutex.Unlock()
+
+	table.IPv4 = nil
+	table.IPv6 = nil
+}
+
+func (table *AllowedIPs) RemoveByPeer(peer *Peer) {
+	table.mutex.Lock()
+	defer table.mutex.Unlock()
+
+	table.IPv4 = table.IPv4.removeByPeer(peer)
+	table.IPv6 = table.IPv6.removeByPeer(peer)
+}
+
+func (table *AllowedIPs) Insert(ip net.IP, cidr uint, peer *Peer) {
+	table.mutex.Lock()
+	defer table.mutex.Unlock()
+
+	switch len(ip) {
+	case net.IPv6len:
+		table.IPv6 = table.IPv6.insert(ip, cidr, peer)
+	case net.IPv4len:
+		table.IPv4 = table.IPv4.insert(ip, cidr, peer)
+	default:
+		panic(errors.New("inserting unknown address type"))
+	}
+}
+
+func (table *AllowedIPs) LookupIPv4(address []byte) *Peer {
+	table.mutex.RLock()
+	defer table.mutex.RUnlock()
+	return table.IPv4.lookup(address)
+}
+
+func (table *AllowedIPs) LookupIPv6(address []byte) *Peer {
+	table.mutex.RLock()
+	defer table.mutex.RUnlock()
+	return table.IPv6.lookup(address)
+}
diff --git a/device/allowedips_rand_test.go b/device/allowedips_rand_test.go
new file mode 100644
index 0000000..59c10f7
--- /dev/null
+++ b/device/allowedips_rand_test.go
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"math/rand"
+	"sort"
+	"testing"
+)
+
+const (
+	NumberOfPeers     = 100
+	NumberOfAddresses = 250
+	NumberOfTests     = 10000
+)
+
+type SlowNode struct {
+	peer *Peer
+	cidr uint
+	bits []byte
+}
+
+type SlowRouter []*SlowNode
+
+func (r SlowRouter) Len() int {
+	return len(r)
+}
+
+func (r SlowRouter) Less(i, j int) bool {
+	return r[i].cidr > r[j].cidr
+}
+
+func (r SlowRouter) Swap(i, j int) {
+	r[i], r[j] = r[j], r[i]
+}
+
+func (r SlowRouter) Insert(addr []byte, cidr uint, peer *Peer) SlowRouter {
+	for _, t := range r {
+		if t.cidr == cidr && commonBits(t.bits, addr) >= cidr {
+			t.peer = peer
+			t.bits = addr
+			return r
+		}
+	}
+	r = append(r, &SlowNode{
+		cidr: cidr,
+		bits: addr,
+		peer: peer,
+	})
+	sort.Sort(r)
+	return r
+}
+
+func (r SlowRouter) Lookup(addr []byte) *Peer {
+	for _, t := range r {
+		common := commonBits(t.bits, addr)
+		if common >= t.cidr {
+			return t.peer
+		}
+	}
+	return nil
+}
+
+func TestTrieRandomIPv4(t *testing.T) {
+	var trie *trieEntry
+	var slow SlowRouter
+	var peers []*Peer
+
+	rand.Seed(1)
+
+	const AddressLength = 4
+
+	for n := 0; n < NumberOfPeers; n += 1 {
+		peers = append(peers, &Peer{})
+	}
+
+	for n := 0; n < NumberOfAddresses; n += 1 {
+		var addr [AddressLength]byte
+		rand.Read(addr[:])
+		cidr := uint(rand.Uint32() % (AddressLength * 8))
+		index := rand.Int() % NumberOfPeers
+		trie = trie.insert(addr[:], cidr, peers[index])
+		slow = slow.Insert(addr[:], cidr, peers[index])
+	}
+
+	for n := 0; n < NumberOfTests; n += 1 {
+		var addr [AddressLength]byte
+		rand.Read(addr[:])
+		peer1 := slow.Lookup(addr[:])
+		peer2 := trie.lookup(addr[:])
+		if peer1 != peer2 {
+			t.Error("Trie did not match naive implementation, for:", addr)
+		}
+	}
+}
+
+func TestTrieRandomIPv6(t *testing.T) {
+	var trie *trieEntry
+	var slow SlowRouter
+	var peers []*Peer
+
+	rand.Seed(1)
+
+	const AddressLength = 16
+
+	for n := 0; n < NumberOfPeers; n += 1 {
+		peers = append(peers, &Peer{})
+	}
+
+	for n := 0; n < NumberOfAddresses; n += 1 {
+		var addr [AddressLength]byte
+		rand.Read(addr[:])
+		cidr := uint(rand.Uint32() % (AddressLength * 8))
+		index := rand.Int() % NumberOfPeers
+		trie = trie.insert(addr[:], cidr, peers[index])
+		slow = slow.Insert(addr[:], cidr, peers[index])
+	}
+
+	for n := 0; n < NumberOfTests; n += 1 {
+		var addr [AddressLength]byte
+		rand.Read(addr[:])
+		peer1 := slow.Lookup(addr[:])
+		peer2 := trie.lookup(addr[:])
+		if peer1 != peer2 {
+			t.Error("Trie did not match naive implementation, for:", addr)
+		}
+	}
+}
diff --git a/device/allowedips_test.go b/device/allowedips_test.go
new file mode 100644
index 0000000..075ff06
--- /dev/null
+++ b/device/allowedips_test.go
@@ -0,0 +1,260 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"math/rand"
+	"net"
+	"testing"
+)
+
+/* Todo: More comprehensive
+ */
+
+type testPairCommonBits struct {
+	s1    []byte
+	s2    []byte
+	match uint
+}
+
+type testPairTrieInsert struct {
+	key  []byte
+	cidr uint
+	peer *Peer
+}
+
+type testPairTrieLookup struct {
+	key  []byte
+	peer *Peer
+}
+
+func printTrie(t *testing.T, p *trieEntry) {
+	if p == nil {
+		return
+	}
+	t.Log(p)
+	printTrie(t, p.child[0])
+	printTrie(t, p.child[1])
+}
+
+func TestCommonBits(t *testing.T) {
+
+	tests := []testPairCommonBits{
+		{s1: []byte{1, 4, 53, 128}, s2: []byte{0, 0, 0, 0}, match: 7},
+		{s1: []byte{0, 4, 53, 128}, s2: []byte{0, 0, 0, 0}, match: 13},
+		{s1: []byte{0, 4, 53, 253}, s2: []byte{0, 4, 53, 252}, match: 31},
+		{s1: []byte{192, 168, 1, 1}, s2: []byte{192, 169, 1, 1}, match: 15},
+		{s1: []byte{65, 168, 1, 1}, s2: []byte{192, 169, 1, 1}, match: 0},
+	}
+
+	for _, p := range tests {
+		v := commonBits(p.s1, p.s2)
+		if v != p.match {
+			t.Error(
+				"For slice", p.s1, p.s2,
+				"expected match", p.match,
+				",but got", v,
+			)
+		}
+	}
+}
+
+func benchmarkTrie(peerNumber int, addressNumber int, addressLength int, b *testing.B) {
+	var trie *trieEntry
+	var peers []*Peer
+
+	rand.Seed(1)
+
+	const AddressLength = 4
+
+	for n := 0; n < peerNumber; n += 1 {
+		peers = append(peers, &Peer{})
+	}
+
+	for n := 0; n < addressNumber; n += 1 {
+		var addr [AddressLength]byte
+		rand.Read(addr[:])
+		cidr := uint(rand.Uint32() % (AddressLength * 8))
+		index := rand.Int() % peerNumber
+		trie = trie.insert(addr[:], cidr, peers[index])
+	}
+
+	for n := 0; n < b.N; n += 1 {
+		var addr [AddressLength]byte
+		rand.Read(addr[:])
+		trie.lookup(addr[:])
+	}
+}
+
+func BenchmarkTrieIPv4Peers100Addresses1000(b *testing.B) {
+	benchmarkTrie(100, 1000, net.IPv4len, b)
+}
+
+func BenchmarkTrieIPv4Peers10Addresses10(b *testing.B) {
+	benchmarkTrie(10, 10, net.IPv4len, b)
+}
+
+func BenchmarkTrieIPv6Peers100Addresses1000(b *testing.B) {
+	benchmarkTrie(100, 1000, net.IPv6len, b)
+}
+
+func BenchmarkTrieIPv6Peers10Addresses10(b *testing.B) {
+	benchmarkTrie(10, 10, net.IPv6len, b)
+}
+
+/* Test ported from kernel implementation:
+ * selftest/allowedips.h
+ */
+func TestTrieIPv4(t *testing.T) {
+	a := &Peer{}
+	b := &Peer{}
+	c := &Peer{}
+	d := &Peer{}
+	e := &Peer{}
+	g := &Peer{}
+	h := &Peer{}
+
+	var trie *trieEntry
+
+	insert := func(peer *Peer, a, b, c, d byte, cidr uint) {
+		trie = trie.insert([]byte{a, b, c, d}, cidr, peer)
+	}
+
+	assertEQ := func(peer *Peer, a, b, c, d byte) {
+		p := trie.lookup([]byte{a, b, c, d})
+		if p != peer {
+			t.Error("Assert EQ failed")
+		}
+	}
+
+	assertNEQ := func(peer *Peer, a, b, c, d byte) {
+		p := trie.lookup([]byte{a, b, c, d})
+		if p == peer {
+			t.Error("Assert NEQ failed")
+		}
+	}
+
+	insert(a, 192, 168, 4, 0, 24)
+	insert(b, 192, 168, 4, 4, 32)
+	insert(c, 192, 168, 0, 0, 16)
+	insert(d, 192, 95, 5, 64, 27)
+	insert(c, 192, 95, 5, 65, 27)
+	insert(e, 0, 0, 0, 0, 0)
+	insert(g, 64, 15, 112, 0, 20)
+	insert(h, 64, 15, 123, 211, 25)
+	insert(a, 10, 0, 0, 0, 25)
+	insert(b, 10, 0, 0, 128, 25)
+	insert(a, 10, 1, 0, 0, 30)
+	insert(b, 10, 1, 0, 4, 30)
+	insert(c, 10, 1, 0, 8, 29)
+	insert(d, 10, 1, 0, 16, 29)
+
+	assertEQ(a, 192, 168, 4, 20)
+	assertEQ(a, 192, 168, 4, 0)
+	assertEQ(b, 192, 168, 4, 4)
+	assertEQ(c, 192, 168, 200, 182)
+	assertEQ(c, 192, 95, 5, 68)
+	assertEQ(e, 192, 95, 5, 96)
+	assertEQ(g, 64, 15, 116, 26)
+	assertEQ(g, 64, 15, 127, 3)
+
+	insert(a, 1, 0, 0, 0, 32)
+	insert(a, 64, 0, 0, 0, 32)
+	insert(a, 128, 0, 0, 0, 32)
+	insert(a, 192, 0, 0, 0, 32)
+	insert(a, 255, 0, 0, 0, 32)
+
+	assertEQ(a, 1, 0, 0, 0)
+	assertEQ(a, 64, 0, 0, 0)
+	assertEQ(a, 128, 0, 0, 0)
+	assertEQ(a, 192, 0, 0, 0)
+	assertEQ(a, 255, 0, 0, 0)
+
+	trie = trie.removeByPeer(a)
+
+	assertNEQ(a, 1, 0, 0, 0)
+	assertNEQ(a, 64, 0, 0, 0)
+	assertNEQ(a, 128, 0, 0, 0)
+	assertNEQ(a, 192, 0, 0, 0)
+	assertNEQ(a, 255, 0, 0, 0)
+
+	trie = nil
+
+	insert(a, 192, 168, 0, 0, 16)
+	insert(a, 192, 168, 0, 0, 24)
+
+	trie = trie.removeByPeer(a)
+
+	assertNEQ(a, 192, 168, 0, 1)
+}
+
+/* Test ported from kernel implementation:
+ * selftest/allowedips.h
+ */
+func TestTrieIPv6(t *testing.T) {
+	a := &Peer{}
+	b := &Peer{}
+	c := &Peer{}
+	d := &Peer{}
+	e := &Peer{}
+	f := &Peer{}
+	g := &Peer{}
+	h := &Peer{}
+
+	var trie *trieEntry
+
+	expand := func(a uint32) []byte {
+		var out [4]byte
+		out[0] = byte(a >> 24 & 0xff)
+		out[1] = byte(a >> 16 & 0xff)
+		out[2] = byte(a >> 8 & 0xff)
+		out[3] = byte(a & 0xff)
+		return out[:]
+	}
+
+	insert := func(peer *Peer, a, b, c, d uint32, cidr uint) {
+		var addr []byte
+		addr = append(addr, expand(a)...)
+		addr = append(addr, expand(b)...)
+		addr = append(addr, expand(c)...)
+		addr = append(addr, expand(d)...)
+		trie = trie.insert(addr, cidr, peer)
+	}
+
+	assertEQ := func(peer *Peer, a, b, c, d uint32) {
+		var addr []byte
+		addr = append(addr, expand(a)...)
+		addr = append(addr, expand(b)...)
+		addr = append(addr, expand(c)...)
+		addr = append(addr, expand(d)...)
+		p := trie.lookup(addr)
+		if p != peer {
+			t.Error("Assert EQ failed")
+		}
+	}
+
+	insert(d, 0x26075300, 0x60006b00, 0, 0xc05f0543, 128)
+	insert(c, 0x26075300, 0x60006b00, 0, 0, 64)
+	insert(e, 0, 0, 0, 0, 0)
+	insert(f, 0, 0, 0, 0, 0)
+	insert(g, 0x24046800, 0, 0, 0, 32)
+	insert(h, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef, 64)
+	insert(a, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef, 128)
+	insert(c, 0x24446800, 0x40e40800, 0xdeaebeef, 0xdefbeef, 128)
+	insert(b, 0x24446800, 0xf0e40800, 0xeeaebeef, 0, 98)
+
+	assertEQ(d, 0x26075300, 0x60006b00, 0, 0xc05f0543)
+	assertEQ(c, 0x26075300, 0x60006b00, 0, 0xc02e01ee)
+	assertEQ(f, 0x26075300, 0x60006b01, 0, 0)
+	assertEQ(g, 0x24046800, 0x40040806, 0, 0x1006)
+	assertEQ(g, 0x24046800, 0x40040806, 0x1234, 0x5678)
+	assertEQ(f, 0x240467ff, 0x40040806, 0x1234, 0x5678)
+	assertEQ(f, 0x24046801, 0x40040806, 0x1234, 0x5678)
+	assertEQ(h, 0x24046800, 0x40040800, 0x1234, 0x5678)
+	assertEQ(h, 0x24046800, 0x40040800, 0, 0)
+	assertEQ(h, 0x24046800, 0x40040800, 0x10101010, 0x10101010)
+	assertEQ(a, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef)
+}
diff --git a/device/bind_test.go b/device/bind_test.go
new file mode 100644
index 0000000..0c2e2cf
--- /dev/null
+++ b/device/bind_test.go
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import "errors"
+
+type DummyDatagram struct {
+	msg      []byte
+	endpoint Endpoint
+	world    bool // better type
+}
+
+type DummyBind struct {
+	in6    chan DummyDatagram
+	ou6    chan DummyDatagram
+	in4    chan DummyDatagram
+	ou4    chan DummyDatagram
+	closed bool
+}
+
+func (b *DummyBind) SetMark(v uint32) error {
+	return nil
+}
+
+func (b *DummyBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+	datagram, ok := <-b.in6
+	if !ok {
+		return 0, nil, errors.New("closed")
+	}
+	copy(buff, datagram.msg)
+	return len(datagram.msg), datagram.endpoint, nil
+}
+
+func (b *DummyBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+	datagram, ok := <-b.in4
+	if !ok {
+		return 0, nil, errors.New("closed")
+	}
+	copy(buff, datagram.msg)
+	return len(datagram.msg), datagram.endpoint, nil
+}
+
+func (b *DummyBind) Close() error {
+	close(b.in6)
+	close(b.in4)
+	b.closed = true
+	return nil
+}
+
+func (b *DummyBind) Send(buff []byte, end Endpoint) error {
+	return nil
+}
diff --git a/device/conn.go b/device/conn.go
new file mode 100644
index 0000000..2594680
--- /dev/null
+++ b/device/conn.go
@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"errors"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+	"net"
+)
+
+const (
+	ConnRoutineNumber = 2
+)
+
+/* A Bind handles listening on a port for both IPv6 and IPv4 UDP traffic
+ */
+type Bind interface {
+	SetMark(value uint32) error
+	ReceiveIPv6(buff []byte) (int, Endpoint, error)
+	ReceiveIPv4(buff []byte) (int, Endpoint, error)
+	Send(buff []byte, end Endpoint) error
+	Close() error
+}
+
+/* An Endpoint maintains the source/destination caching for a peer
+ *
+ * dst : the remote address of a peer ("endpoint" in uapi terminology)
+ * src : the local address from which datagrams originate going to the peer
+ */
+type Endpoint interface {
+	ClearSrc()           // clears the source address
+	SrcToString() string // returns the local source address (ip:port)
+	DstToString() string // returns the destination address (ip:port)
+	DstToBytes() []byte  // used for mac2 cookie calculations
+	DstIP() net.IP
+	SrcIP() net.IP
+}
+
+func parseEndpoint(s string) (*net.UDPAddr, error) {
+
+	// ensure that the host is an IP address
+
+	host, _, err := net.SplitHostPort(s)
+	if err != nil {
+		return nil, err
+	}
+	if ip := net.ParseIP(host); ip == nil {
+		return nil, errors.New("Failed to parse IP address: " + host)
+	}
+
+	// parse address and port
+
+	addr, err := net.ResolveUDPAddr("udp", s)
+	if err != nil {
+		return nil, err
+	}
+	ip4 := addr.IP.To4()
+	if ip4 != nil {
+		addr.IP = ip4
+	}
+	return addr, err
+}
+
+func unsafeCloseBind(device *Device) error {
+	var err error
+	netc := &device.net
+	if netc.bind != nil {
+		err = netc.bind.Close()
+		netc.bind = nil
+	}
+	netc.stopping.Wait()
+	return err
+}
+
+func (device *Device) BindSetMark(mark uint32) error {
+
+	device.net.Lock()
+	defer device.net.Unlock()
+
+	// check if modified
+
+	if device.net.fwmark == mark {
+		return nil
+	}
+
+	// update fwmark on existing bind
+
+	device.net.fwmark = mark
+	if device.isUp.Get() && device.net.bind != nil {
+		if err := device.net.bind.SetMark(mark); err != nil {
+			return err
+		}
+	}
+
+	// clear cached source addresses
+
+	device.peers.RLock()
+	for _, peer := range device.peers.keyMap {
+		peer.Lock()
+		defer peer.Unlock()
+		if peer.endpoint != nil {
+			peer.endpoint.ClearSrc()
+		}
+	}
+	device.peers.RUnlock()
+
+	return nil
+}
+
+func (device *Device) BindUpdate() error {
+
+	device.net.Lock()
+	defer device.net.Unlock()
+
+	// close existing sockets
+
+	if err := unsafeCloseBind(device); err != nil {
+		return err
+	}
+
+	// open new sockets
+
+	if device.isUp.Get() {
+
+		// bind to new port
+
+		var err error
+		netc := &device.net
+		netc.bind, netc.port, err = CreateBind(netc.port, device)
+		if err != nil {
+			netc.bind = nil
+			netc.port = 0
+			return err
+		}
+
+		// set fwmark
+
+		if netc.fwmark != 0 {
+			err = netc.bind.SetMark(netc.fwmark)
+			if err != nil {
+				return err
+			}
+		}
+
+		// clear cached source addresses
+
+		device.peers.RLock()
+		for _, peer := range device.peers.keyMap {
+			peer.Lock()
+			defer peer.Unlock()
+			if peer.endpoint != nil {
+				peer.endpoint.ClearSrc()
+			}
+		}
+		device.peers.RUnlock()
+
+		// start receiving routines
+
+		device.net.starting.Add(ConnRoutineNumber)
+		device.net.stopping.Add(ConnRoutineNumber)
+		go device.RoutineReceiveIncoming(ipv4.Version, netc.bind)
+		go device.RoutineReceiveIncoming(ipv6.Version, netc.bind)
+		device.net.starting.Wait()
+
+		device.log.Debug.Println("UDP bind has been updated")
+	}
+
+	return nil
+}
+
+func (device *Device) BindClose() error {
+	device.net.Lock()
+	err := unsafeCloseBind(device)
+	device.net.Unlock()
+	return err
+}
\ No newline at end of file
diff --git a/device/conn_default.go b/device/conn_default.go
new file mode 100644
index 0000000..8a86719
--- /dev/null
+++ b/device/conn_default.go
@@ -0,0 +1,170 @@
+// +build !linux android
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"net"
+	"os"
+	"syscall"
+)
+
+/* This code is meant to be a temporary solution
+ * on platforms for which the sticky socket / source caching behavior
+ * has not yet been implemented.
+ *
+ * See conn_linux.go for an implementation on the linux platform.
+ */
+
+type NativeBind struct {
+	ipv4 *net.UDPConn
+	ipv6 *net.UDPConn
+}
+
+type NativeEndpoint net.UDPAddr
+
+var _ Bind = (*NativeBind)(nil)
+var _ Endpoint = (*NativeEndpoint)(nil)
+
+func CreateEndpoint(s string) (Endpoint, error) {
+	addr, err := parseEndpoint(s)
+	return (*NativeEndpoint)(addr), err
+}
+
+func (_ *NativeEndpoint) ClearSrc() {}
+
+func (e *NativeEndpoint) DstIP() net.IP {
+	return (*net.UDPAddr)(e).IP
+}
+
+func (e *NativeEndpoint) SrcIP() net.IP {
+	return nil // not supported
+}
+
+func (e *NativeEndpoint) DstToBytes() []byte {
+	addr := (*net.UDPAddr)(e)
+	out := addr.IP.To4()
+	if out == nil {
+		out = addr.IP
+	}
+	out = append(out, byte(addr.Port&0xff))
+	out = append(out, byte((addr.Port>>8)&0xff))
+	return out
+}
+
+func (e *NativeEndpoint) DstToString() string {
+	return (*net.UDPAddr)(e).String()
+}
+
+func (e *NativeEndpoint) SrcToString() string {
+	return ""
+}
+
+func listenNet(network string, port int) (*net.UDPConn, int, error) {
+
+	// listen
+
+	conn, err := net.ListenUDP(network, &net.UDPAddr{Port: port})
+	if err != nil {
+		return nil, 0, err
+	}
+
+	// retrieve port
+
+	laddr := conn.LocalAddr()
+	uaddr, err := net.ResolveUDPAddr(
+		laddr.Network(),
+		laddr.String(),
+	)
+	if err != nil {
+		return nil, 0, err
+	}
+	return conn, uaddr.Port, nil
+}
+
+func extractErrno(err error) error {
+	opErr, ok := err.(*net.OpError)
+	if !ok {
+		return nil
+	}
+	syscallErr, ok := opErr.Err.(*os.SyscallError)
+	if !ok {
+		return nil
+	}
+	return syscallErr.Err
+}
+
+func CreateBind(uport uint16, device *Device) (Bind, uint16, error) {
+	var err error
+	var bind NativeBind
+
+	port := int(uport)
+
+	bind.ipv4, port, err = listenNet("udp4", port)
+	if err != nil && extractErrno(err) != syscall.EAFNOSUPPORT {
+		return nil, 0, err
+	}
+
+	bind.ipv6, port, err = listenNet("udp6", port)
+	if err != nil && extractErrno(err) != syscall.EAFNOSUPPORT {
+		bind.ipv4.Close()
+		bind.ipv4 = nil
+		return nil, 0, err
+	}
+
+	return &bind, uint16(port), nil
+}
+
+func (bind *NativeBind) Close() error {
+	var err1, err2 error
+	if bind.ipv4 != nil {
+		err1 = bind.ipv4.Close()
+	}
+	if bind.ipv6 != nil {
+		err2 = bind.ipv6.Close()
+	}
+	if err1 != nil {
+		return err1
+	}
+	return err2
+}
+
+func (bind *NativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+	if bind.ipv4 == nil {
+		return 0, nil, syscall.EAFNOSUPPORT
+	}
+	n, endpoint, err := bind.ipv4.ReadFromUDP(buff)
+	if endpoint != nil {
+		endpoint.IP = endpoint.IP.To4()
+	}
+	return n, (*NativeEndpoint)(endpoint), err
+}
+
+func (bind *NativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+	if bind.ipv6 == nil {
+		return 0, nil, syscall.EAFNOSUPPORT
+	}
+	n, endpoint, err := bind.ipv6.ReadFromUDP(buff)
+	return n, (*NativeEndpoint)(endpoint), err
+}
+
+func (bind *NativeBind) Send(buff []byte, endpoint Endpoint) error {
+	var err error
+	nend := endpoint.(*NativeEndpoint)
+	if nend.IP.To4() != nil {
+		if bind.ipv4 == nil {
+			return syscall.EAFNOSUPPORT
+		}
+		_, err = bind.ipv4.WriteToUDP(buff, (*net.UDPAddr)(nend))
+	} else {
+		if bind.ipv6 == nil {
+			return syscall.EAFNOSUPPORT
+		}
+		_, err = bind.ipv6.WriteToUDP(buff, (*net.UDPAddr)(nend))
+	}
+	return err
+}
diff --git a/device/conn_linux.go b/device/conn_linux.go
new file mode 100644
index 0000000..49949d5
--- /dev/null
+++ b/device/conn_linux.go
@@ -0,0 +1,746 @@
+// +build !android
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ *
+ * This implements userspace semantics of "sticky sockets", modeled after
+ * WireGuard's kernelspace implementation. This is more or less a straight port
+ * of the sticky-sockets.c example code:
+ * https://git.zx2c4.com/WireGuard/tree/contrib/examples/sticky-sockets/sticky-sockets.c
+ *
+ * Currently there is no way to achieve this within the net package:
+ * See e.g. https://github.com/golang/go/issues/17930
+ * So this code is remains platform dependent.
+ */
+
+package device
+
+import (
+	"errors"
+	"golang.org/x/sys/unix"
+	"golang.zx2c4.com/wireguard/rwcancel"
+	"net"
+	"strconv"
+	"sync"
+	"syscall"
+	"unsafe"
+)
+
+const (
+	FD_ERR = -1
+)
+
+type IPv4Source struct {
+	src     [4]byte
+	ifindex int32
+}
+
+type IPv6Source struct {
+	src [16]byte
+	//ifindex belongs in dst.ZoneId
+}
+
+type NativeEndpoint struct {
+	dst  [unsafe.Sizeof(unix.SockaddrInet6{})]byte
+	src  [unsafe.Sizeof(IPv6Source{})]byte
+	isV6 bool
+}
+
+func (endpoint *NativeEndpoint) src4() *IPv4Source {
+	return (*IPv4Source)(unsafe.Pointer(&endpoint.src[0]))
+}
+
+func (endpoint *NativeEndpoint) src6() *IPv6Source {
+	return (*IPv6Source)(unsafe.Pointer(&endpoint.src[0]))
+}
+
+func (endpoint *NativeEndpoint) dst4() *unix.SockaddrInet4 {
+	return (*unix.SockaddrInet4)(unsafe.Pointer(&endpoint.dst[0]))
+}
+
+func (endpoint *NativeEndpoint) dst6() *unix.SockaddrInet6 {
+	return (*unix.SockaddrInet6)(unsafe.Pointer(&endpoint.dst[0]))
+}
+
+type NativeBind struct {
+	sock4         int
+	sock6         int
+	netlinkSock   int
+	netlinkCancel *rwcancel.RWCancel
+	lastMark      uint32
+}
+
+var _ Endpoint = (*NativeEndpoint)(nil)
+var _ Bind = (*NativeBind)(nil)
+
+func CreateEndpoint(s string) (Endpoint, error) {
+	var end NativeEndpoint
+	addr, err := parseEndpoint(s)
+	if err != nil {
+		return nil, err
+	}
+
+	ipv4 := addr.IP.To4()
+	if ipv4 != nil {
+		dst := end.dst4()
+		end.isV6 = false
+		dst.Port = addr.Port
+		copy(dst.Addr[:], ipv4)
+		end.ClearSrc()
+		return &end, nil
+	}
+
+	ipv6 := addr.IP.To16()
+	if ipv6 != nil {
+		zone, err := zoneToUint32(addr.Zone)
+		if err != nil {
+			return nil, err
+		}
+		dst := end.dst6()
+		end.isV6 = true
+		dst.Port = addr.Port
+		dst.ZoneId = zone
+		copy(dst.Addr[:], ipv6[:])
+		end.ClearSrc()
+		return &end, nil
+	}
+
+	return nil, errors.New("Invalid IP address")
+}
+
+func createNetlinkRouteSocket() (int, error) {
+	sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE)
+	if err != nil {
+		return -1, err
+	}
+	saddr := &unix.SockaddrNetlink{
+		Family: unix.AF_NETLINK,
+		Groups: uint32(1 << (unix.RTNLGRP_IPV4_ROUTE - 1)),
+	}
+	err = unix.Bind(sock, saddr)
+	if err != nil {
+		unix.Close(sock)
+		return -1, err
+	}
+	return sock, nil
+
+}
+
+func CreateBind(port uint16, device *Device) (*NativeBind, uint16, error) {
+	var err error
+	var bind NativeBind
+	var newPort uint16
+
+	bind.netlinkSock, err = createNetlinkRouteSocket()
+	if err != nil {
+		return nil, 0, err
+	}
+	bind.netlinkCancel, err = rwcancel.NewRWCancel(bind.netlinkSock)
+	if err != nil {
+		unix.Close(bind.netlinkSock)
+		return nil, 0, err
+	}
+
+	go bind.routineRouteListener(device)
+
+	// attempt ipv6 bind, update port if succesful
+
+	bind.sock6, newPort, err = create6(port)
+	if err != nil {
+		if err != syscall.EAFNOSUPPORT {
+			bind.netlinkCancel.Cancel()
+			return nil, 0, err
+		}
+	} else {
+		port = newPort
+	}
+
+	// attempt ipv4 bind, update port if succesful
+
+	bind.sock4, newPort, err = create4(port)
+	if err != nil {
+		if err != syscall.EAFNOSUPPORT {
+			bind.netlinkCancel.Cancel()
+			unix.Close(bind.sock6)
+			return nil, 0, err
+		}
+	} else {
+		port = newPort
+	}
+
+	if bind.sock4 == FD_ERR && bind.sock6 == FD_ERR {
+		return nil, 0, errors.New("ipv4 and ipv6 not supported")
+	}
+
+	return &bind, port, nil
+}
+
+func (bind *NativeBind) SetMark(value uint32) error {
+	if bind.sock6 != -1 {
+		err := unix.SetsockoptInt(
+			bind.sock6,
+			unix.SOL_SOCKET,
+			unix.SO_MARK,
+			int(value),
+		)
+
+		if err != nil {
+			return err
+		}
+	}
+
+	if bind.sock4 != -1 {
+		err := unix.SetsockoptInt(
+			bind.sock4,
+			unix.SOL_SOCKET,
+			unix.SO_MARK,
+			int(value),
+		)
+
+		if err != nil {
+			return err
+		}
+	}
+
+	bind.lastMark = value
+	return nil
+}
+
+func closeUnblock(fd int) error {
+	// shutdown to unblock readers and writers
+	unix.Shutdown(fd, unix.SHUT_RDWR)
+	return unix.Close(fd)
+}
+
+func (bind *NativeBind) Close() error {
+	var err1, err2, err3 error
+	if bind.sock6 != -1 {
+		err1 = closeUnblock(bind.sock6)
+	}
+	if bind.sock4 != -1 {
+		err2 = closeUnblock(bind.sock4)
+	}
+	err3 = bind.netlinkCancel.Cancel()
+
+	if err1 != nil {
+		return err1
+	}
+	if err2 != nil {
+		return err2
+	}
+	return err3
+}
+
+func (bind *NativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+	var end NativeEndpoint
+	if bind.sock6 == -1 {
+		return 0, nil, syscall.EAFNOSUPPORT
+	}
+	n, err := receive6(
+		bind.sock6,
+		buff,
+		&end,
+	)
+	return n, &end, err
+}
+
+func (bind *NativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+	var end NativeEndpoint
+	if bind.sock4 == -1 {
+		return 0, nil, syscall.EAFNOSUPPORT
+	}
+	n, err := receive4(
+		bind.sock4,
+		buff,
+		&end,
+	)
+	return n, &end, err
+}
+
+func (bind *NativeBind) Send(buff []byte, end Endpoint) error {
+	nend := end.(*NativeEndpoint)
+	if !nend.isV6 {
+		if bind.sock4 == -1 {
+			return syscall.EAFNOSUPPORT
+		}
+		return send4(bind.sock4, nend, buff)
+	} else {
+		if bind.sock6 == -1 {
+			return syscall.EAFNOSUPPORT
+		}
+		return send6(bind.sock6, nend, buff)
+	}
+}
+
+func (end *NativeEndpoint) SrcIP() net.IP {
+	if !end.isV6 {
+		return net.IPv4(
+			end.src4().src[0],
+			end.src4().src[1],
+			end.src4().src[2],
+			end.src4().src[3],
+		)
+	} else {
+		return end.src6().src[:]
+	}
+}
+
+func (end *NativeEndpoint) DstIP() net.IP {
+	if !end.isV6 {
+		return net.IPv4(
+			end.dst4().Addr[0],
+			end.dst4().Addr[1],
+			end.dst4().Addr[2],
+			end.dst4().Addr[3],
+		)
+	} else {
+		return end.dst6().Addr[:]
+	}
+}
+
+func (end *NativeEndpoint) DstToBytes() []byte {
+	if !end.isV6 {
+		return (*[unsafe.Offsetof(end.dst4().Addr) + unsafe.Sizeof(end.dst4().Addr)]byte)(unsafe.Pointer(end.dst4()))[:]
+	} else {
+		return (*[unsafe.Offsetof(end.dst6().Addr) + unsafe.Sizeof(end.dst6().Addr)]byte)(unsafe.Pointer(end.dst6()))[:]
+	}
+}
+
+func (end *NativeEndpoint) SrcToString() string {
+	return end.SrcIP().String()
+}
+
+func (end *NativeEndpoint) DstToString() string {
+	var udpAddr net.UDPAddr
+	udpAddr.IP = end.DstIP()
+	if !end.isV6 {
+		udpAddr.Port = end.dst4().Port
+	} else {
+		udpAddr.Port = end.dst6().Port
+	}
+	return udpAddr.String()
+}
+
+func (end *NativeEndpoint) ClearDst() {
+	for i := range end.dst {
+		end.dst[i] = 0
+	}
+}
+
+func (end *NativeEndpoint) ClearSrc() {
+	for i := range end.src {
+		end.src[i] = 0
+	}
+}
+
+func zoneToUint32(zone string) (uint32, error) {
+	if zone == "" {
+		return 0, nil
+	}
+	if intr, err := net.InterfaceByName(zone); err == nil {
+		return uint32(intr.Index), nil
+	}
+	n, err := strconv.ParseUint(zone, 10, 32)
+	return uint32(n), err
+}
+
+func create4(port uint16) (int, uint16, error) {
+
+	// create socket
+
+	fd, err := unix.Socket(
+		unix.AF_INET,
+		unix.SOCK_DGRAM,
+		0,
+	)
+
+	if err != nil {
+		return FD_ERR, 0, err
+	}
+
+	addr := unix.SockaddrInet4{
+		Port: int(port),
+	}
+
+	// set sockopts and bind
+
+	if err := func() error {
+		if err := unix.SetsockoptInt(
+			fd,
+			unix.SOL_SOCKET,
+			unix.SO_REUSEADDR,
+			1,
+		); err != nil {
+			return err
+		}
+
+		if err := unix.SetsockoptInt(
+			fd,
+			unix.IPPROTO_IP,
+			unix.IP_PKTINFO,
+			1,
+		); err != nil {
+			return err
+		}
+
+		return unix.Bind(fd, &addr)
+	}(); err != nil {
+		unix.Close(fd)
+		return FD_ERR, 0, err
+	}
+
+	return fd, uint16(addr.Port), err
+}
+
+func create6(port uint16) (int, uint16, error) {
+
+	// create socket
+
+	fd, err := unix.Socket(
+		unix.AF_INET6,
+		unix.SOCK_DGRAM,
+		0,
+	)
+
+	if err != nil {
+		return FD_ERR, 0, err
+	}
+
+	// set sockopts and bind
+
+	addr := unix.SockaddrInet6{
+		Port: int(port),
+	}
+
+	if err := func() error {
+
+		if err := unix.SetsockoptInt(
+			fd,
+			unix.SOL_SOCKET,
+			unix.SO_REUSEADDR,
+			1,
+		); err != nil {
+			return err
+		}
+
+		if err := unix.SetsockoptInt(
+			fd,
+			unix.IPPROTO_IPV6,
+			unix.IPV6_RECVPKTINFO,
+			1,
+		); err != nil {
+			return err
+		}
+
+		if err := unix.SetsockoptInt(
+			fd,
+			unix.IPPROTO_IPV6,
+			unix.IPV6_V6ONLY,
+			1,
+		); err != nil {
+			return err
+		}
+
+		return unix.Bind(fd, &addr)
+
+	}(); err != nil {
+		unix.Close(fd)
+		return FD_ERR, 0, err
+	}
+
+	return fd, uint16(addr.Port), err
+}
+
+func send4(sock int, end *NativeEndpoint, buff []byte) error {
+
+	// construct message header
+
+	cmsg := struct {
+		cmsghdr unix.Cmsghdr
+		pktinfo unix.Inet4Pktinfo
+	}{
+		unix.Cmsghdr{
+			Level: unix.IPPROTO_IP,
+			Type:  unix.IP_PKTINFO,
+			Len:   unix.SizeofInet4Pktinfo + unix.SizeofCmsghdr,
+		},
+		unix.Inet4Pktinfo{
+			Spec_dst: end.src4().src,
+			Ifindex:  end.src4().ifindex,
+		},
+	}
+
+	_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
+
+	if err == nil {
+		return nil
+	}
+
+	// clear src and retry
+
+	if err == unix.EINVAL {
+		end.ClearSrc()
+		cmsg.pktinfo = unix.Inet4Pktinfo{}
+		_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
+	}
+
+	return err
+}
+
+func send6(sock int, end *NativeEndpoint, buff []byte) error {
+
+	// construct message header
+
+	cmsg := struct {
+		cmsghdr unix.Cmsghdr
+		pktinfo unix.Inet6Pktinfo
+	}{
+		unix.Cmsghdr{
+			Level: unix.IPPROTO_IPV6,
+			Type:  unix.IPV6_PKTINFO,
+			Len:   unix.SizeofInet6Pktinfo + unix.SizeofCmsghdr,
+		},
+		unix.Inet6Pktinfo{
+			Addr:    end.src6().src,
+			Ifindex: end.dst6().ZoneId,
+		},
+	}
+
+	if cmsg.pktinfo.Addr == [16]byte{} {
+		cmsg.pktinfo.Ifindex = 0
+	}
+
+	_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
+
+	if err == nil {
+		return nil
+	}
+
+	// clear src and retry
+
+	if err == unix.EINVAL {
+		end.ClearSrc()
+		cmsg.pktinfo = unix.Inet6Pktinfo{}
+		_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
+	}
+
+	return err
+}
+
+func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
+
+	// contruct message header
+
+	var cmsg struct {
+		cmsghdr unix.Cmsghdr
+		pktinfo unix.Inet4Pktinfo
+	}
+
+	size, _, _, newDst, err := unix.Recvmsg(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], 0)
+
+	if err != nil {
+		return 0, err
+	}
+	end.isV6 = false
+
+	if newDst4, ok := newDst.(*unix.SockaddrInet4); ok {
+		*end.dst4() = *newDst4
+	}
+
+	// update source cache
+
+	if cmsg.cmsghdr.Level == unix.IPPROTO_IP &&
+		cmsg.cmsghdr.Type == unix.IP_PKTINFO &&
+		cmsg.cmsghdr.Len >= unix.SizeofInet4Pktinfo {
+		end.src4().src = cmsg.pktinfo.Spec_dst
+		end.src4().ifindex = cmsg.pktinfo.Ifindex
+	}
+
+	return size, nil
+}
+
+func receive6(sock int, buff []byte, end *NativeEndpoint) (int, error) {
+
+	// contruct message header
+
+	var cmsg struct {
+		cmsghdr unix.Cmsghdr
+		pktinfo unix.Inet6Pktinfo
+	}
+
+	size, _, _, newDst, err := unix.Recvmsg(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], 0)
+
+	if err != nil {
+		return 0, err
+	}
+	end.isV6 = true
+
+	if newDst6, ok := newDst.(*unix.SockaddrInet6); ok {
+		*end.dst6() = *newDst6
+	}
+
+	// update source cache
+
+	if cmsg.cmsghdr.Level == unix.IPPROTO_IPV6 &&
+		cmsg.cmsghdr.Type == unix.IPV6_PKTINFO &&
+		cmsg.cmsghdr.Len >= unix.SizeofInet6Pktinfo {
+		end.src6().src = cmsg.pktinfo.Addr
+		end.dst6().ZoneId = cmsg.pktinfo.Ifindex
+	}
+
+	return size, nil
+}
+
+func (bind *NativeBind) routineRouteListener(device *Device) {
+	type peerEndpointPtr struct {
+		peer     *Peer
+		endpoint *Endpoint
+	}
+	var reqPeer map[uint32]peerEndpointPtr
+	var reqPeerLock sync.Mutex
+
+	defer unix.Close(bind.netlinkSock)
+
+	for msg := make([]byte, 1<<16); ; {
+		var err error
+		var msgn int
+		for {
+			msgn, _, _, _, err = unix.Recvmsg(bind.netlinkSock, msg[:], nil, 0)
+			if err == nil || !rwcancel.RetryAfterError(err) {
+				break
+			}
+			if !bind.netlinkCancel.ReadyRead() {
+				return
+			}
+		}
+		if err != nil {
+			return
+		}
+
+		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
+
+			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
+
+			if uint(hdr.Len) > uint(len(remain)) {
+				break
+			}
+
+			switch hdr.Type {
+			case unix.RTM_NEWROUTE, unix.RTM_DELROUTE:
+				if hdr.Seq <= MaxPeers && hdr.Seq > 0 {
+					if uint(len(remain)) < uint(hdr.Len) {
+						break
+					}
+					if hdr.Len > unix.SizeofNlMsghdr+unix.SizeofRtMsg {
+						attr := remain[unix.SizeofNlMsghdr+unix.SizeofRtMsg:]
+						for {
+							if uint(len(attr)) < uint(unix.SizeofRtAttr) {
+								break
+							}
+							attrhdr := *(*unix.RtAttr)(unsafe.Pointer(&attr[0]))
+							if attrhdr.Len < unix.SizeofRtAttr || uint(len(attr)) < uint(attrhdr.Len) {
+								break
+							}
+							if attrhdr.Type == unix.RTA_OIF && attrhdr.Len == unix.SizeofRtAttr+4 {
+								ifidx := *(*uint32)(unsafe.Pointer(&attr[unix.SizeofRtAttr]))
+								reqPeerLock.Lock()
+								if reqPeer == nil {
+									reqPeerLock.Unlock()
+									break
+								}
+								pePtr, ok := reqPeer[hdr.Seq]
+								reqPeerLock.Unlock()
+								if !ok {
+									break
+								}
+								pePtr.peer.Lock()
+								if &pePtr.peer.endpoint != pePtr.endpoint {
+									pePtr.peer.Unlock()
+									break
+								}
+								if uint32(pePtr.peer.endpoint.(*NativeEndpoint).src4().ifindex) == ifidx {
+									pePtr.peer.Unlock()
+									break
+								}
+								pePtr.peer.endpoint.(*NativeEndpoint).ClearSrc()
+								pePtr.peer.Unlock()
+							}
+							attr = attr[attrhdr.Len:]
+						}
+					}
+					break
+				}
+				reqPeerLock.Lock()
+				reqPeer = make(map[uint32]peerEndpointPtr)
+				reqPeerLock.Unlock()
+				go func() {
+					device.peers.RLock()
+					i := uint32(1)
+					for _, peer := range device.peers.keyMap {
+						peer.RLock()
+						if peer.endpoint == nil || peer.endpoint.(*NativeEndpoint) == nil {
+							peer.RUnlock()
+							continue
+						}
+						if peer.endpoint.(*NativeEndpoint).isV6 || peer.endpoint.(*NativeEndpoint).src4().ifindex == 0 {
+							peer.RUnlock()
+							break
+						}
+						nlmsg := struct {
+							hdr     unix.NlMsghdr
+							msg     unix.RtMsg
+							dsthdr  unix.RtAttr
+							dst     [4]byte
+							srchdr  unix.RtAttr
+							src     [4]byte
+							markhdr unix.RtAttr
+							mark    uint32
+						}{
+							unix.NlMsghdr{
+								Type:  uint16(unix.RTM_GETROUTE),
+								Flags: unix.NLM_F_REQUEST,
+								Seq:   i,
+							},
+							unix.RtMsg{
+								Family:  unix.AF_INET,
+								Dst_len: 32,
+								Src_len: 32,
+							},
+							unix.RtAttr{
+								Len:  8,
+								Type: unix.RTA_DST,
+							},
+							peer.endpoint.(*NativeEndpoint).dst4().Addr,
+							unix.RtAttr{
+								Len:  8,
+								Type: unix.RTA_SRC,
+							},
+							peer.endpoint.(*NativeEndpoint).src4().src,
+							unix.RtAttr{
+								Len:  8,
+								Type: 0x10, //unix.RTA_MARK  TODO: add this to x/sys/unix
+							},
+							uint32(bind.lastMark),
+						}
+						nlmsg.hdr.Len = uint32(unsafe.Sizeof(nlmsg))
+						reqPeerLock.Lock()
+						reqPeer[i] = peerEndpointPtr{
+							peer:     peer,
+							endpoint: &peer.endpoint,
+						}
+						reqPeerLock.Unlock()
+						peer.RUnlock()
+						i++
+						_, err := bind.netlinkCancel.Write((*[unsafe.Sizeof(nlmsg)]byte)(unsafe.Pointer(&nlmsg))[:])
+						if err != nil {
+							break
+						}
+					}
+					device.peers.RUnlock()
+				}()
+			}
+			remain = remain[hdr.Len:]
+		}
+	}
+}
diff --git a/device/constants.go b/device/constants.go
new file mode 100644
index 0000000..27d910f
--- /dev/null
+++ b/device/constants.go
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"time"
+)
+
+/* Specification constants */
+
+const (
+	RekeyAfterMessages      = (1 << 64) - (1 << 16) - 1
+	RejectAfterMessages     = (1 << 64) - (1 << 4) - 1
+	RekeyAfterTime          = time.Second * 120
+	RekeyAttemptTime        = time.Second * 90
+	RekeyTimeout            = time.Second * 5
+	MaxTimerHandshakes      = 90 / 5 /* RekeyAttemptTime / RekeyTimeout */
+	RekeyTimeoutJitterMaxMs = 334
+	RejectAfterTime         = time.Second * 180
+	KeepaliveTimeout        = time.Second * 10
+	CookieRefreshTime       = time.Second * 120
+	HandshakeInitationRate  = time.Second / 20
+	PaddingMultiple         = 16
+)
+
+const (
+	MinMessageSize = MessageKeepaliveSize                  // minimum size of transport message (keepalive)
+	MaxMessageSize = MaxSegmentSize                        // maximum size of transport message
+	MaxContentSize = MaxSegmentSize - MessageTransportSize // maximum size of transport message content
+)
+
+/* Implementation constants */
+
+const (
+	UnderLoadQueueSize = QueueHandshakeSize / 8
+	UnderLoadAfterTime = time.Second // how long does the device remain under load after detected
+	MaxPeers           = 1 << 16     // maximum number of configured peers
+)
diff --git a/device/cookie.go b/device/cookie.go
new file mode 100644
index 0000000..2f21067
--- /dev/null
+++ b/device/cookie.go
@@ -0,0 +1,250 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"crypto/hmac"
+	"crypto/rand"
+	"golang.org/x/crypto/blake2s"
+	"golang.org/x/crypto/chacha20poly1305"
+	"sync"
+	"time"
+)
+
+type CookieChecker struct {
+	sync.RWMutex
+	mac1 struct {
+		key [blake2s.Size]byte
+	}
+	mac2 struct {
+		secret        [blake2s.Size]byte
+		secretSet     time.Time
+		encryptionKey [chacha20poly1305.KeySize]byte
+	}
+}
+
+type CookieGenerator struct {
+	sync.RWMutex
+	mac1 struct {
+		key [blake2s.Size]byte
+	}
+	mac2 struct {
+		cookie        [blake2s.Size128]byte
+		cookieSet     time.Time
+		hasLastMAC1   bool
+		lastMAC1      [blake2s.Size128]byte
+		encryptionKey [chacha20poly1305.KeySize]byte
+	}
+}
+
+func (st *CookieChecker) Init(pk NoisePublicKey) {
+	st.Lock()
+	defer st.Unlock()
+
+	// mac1 state
+
+	func() {
+		hash, _ := blake2s.New256(nil)
+		hash.Write([]byte(WGLabelMAC1))
+		hash.Write(pk[:])
+		hash.Sum(st.mac1.key[:0])
+	}()
+
+	// mac2 state
+
+	func() {
+		hash, _ := blake2s.New256(nil)
+		hash.Write([]byte(WGLabelCookie))
+		hash.Write(pk[:])
+		hash.Sum(st.mac2.encryptionKey[:0])
+	}()
+
+	st.mac2.secretSet = time.Time{}
+}
+
+func (st *CookieChecker) CheckMAC1(msg []byte) bool {
+	st.RLock()
+	defer st.RUnlock()
+
+	size := len(msg)
+	smac2 := size - blake2s.Size128
+	smac1 := smac2 - blake2s.Size128
+
+	var mac1 [blake2s.Size128]byte
+
+	mac, _ := blake2s.New128(st.mac1.key[:])
+	mac.Write(msg[:smac1])
+	mac.Sum(mac1[:0])
+
+	return hmac.Equal(mac1[:], msg[smac1:smac2])
+}
+
+func (st *CookieChecker) CheckMAC2(msg []byte, src []byte) bool {
+	st.RLock()
+	defer st.RUnlock()
+
+	if time.Now().Sub(st.mac2.secretSet) > CookieRefreshTime {
+		return false
+	}
+
+	// derive cookie key
+
+	var cookie [blake2s.Size128]byte
+	func() {
+		mac, _ := blake2s.New128(st.mac2.secret[:])
+		mac.Write(src)
+		mac.Sum(cookie[:0])
+	}()
+
+	// calculate mac of packet (including mac1)
+
+	smac2 := len(msg) - blake2s.Size128
+
+	var mac2 [blake2s.Size128]byte
+	func() {
+		mac, _ := blake2s.New128(cookie[:])
+		mac.Write(msg[:smac2])
+		mac.Sum(mac2[:0])
+	}()
+
+	return hmac.Equal(mac2[:], msg[smac2:])
+}
+
+func (st *CookieChecker) CreateReply(
+	msg []byte,
+	recv uint32,
+	src []byte,
+) (*MessageCookieReply, error) {
+
+	st.RLock()
+
+	// refresh cookie secret
+
+	if time.Now().Sub(st.mac2.secretSet) > CookieRefreshTime {
+		st.RUnlock()
+		st.Lock()
+		_, err := rand.Read(st.mac2.secret[:])
+		if err != nil {
+			st.Unlock()
+			return nil, err
+		}
+		st.mac2.secretSet = time.Now()
+		st.Unlock()
+		st.RLock()
+	}
+
+	// derive cookie
+
+	var cookie [blake2s.Size128]byte
+	func() {
+		mac, _ := blake2s.New128(st.mac2.secret[:])
+		mac.Write(src)
+		mac.Sum(cookie[:0])
+	}()
+
+	// encrypt cookie
+
+	size := len(msg)
+
+	smac2 := size - blake2s.Size128
+	smac1 := smac2 - blake2s.Size128
+
+	reply := new(MessageCookieReply)
+	reply.Type = MessageCookieReplyType
+	reply.Receiver = recv
+
+	_, err := rand.Read(reply.Nonce[:])
+	if err != nil {
+		st.RUnlock()
+		return nil, err
+	}
+
+	xchapoly, _ := chacha20poly1305.NewX(st.mac2.encryptionKey[:])
+	xchapoly.Seal(reply.Cookie[:0], reply.Nonce[:], cookie[:], msg[smac1:smac2])
+
+	st.RUnlock()
+
+	return reply, nil
+}
+
+func (st *CookieGenerator) Init(pk NoisePublicKey) {
+	st.Lock()
+	defer st.Unlock()
+
+	func() {
+		hash, _ := blake2s.New256(nil)
+		hash.Write([]byte(WGLabelMAC1))
+		hash.Write(pk[:])
+		hash.Sum(st.mac1.key[:0])
+	}()
+
+	func() {
+		hash, _ := blake2s.New256(nil)
+		hash.Write([]byte(WGLabelCookie))
+		hash.Write(pk[:])
+		hash.Sum(st.mac2.encryptionKey[:0])
+	}()
+
+	st.mac2.cookieSet = time.Time{}
+}
+
+func (st *CookieGenerator) ConsumeReply(msg *MessageCookieReply) bool {
+	st.Lock()
+	defer st.Unlock()
+
+	if !st.mac2.hasLastMAC1 {
+		return false
+	}
+
+	var cookie [blake2s.Size128]byte
+
+	xchapoly, _ := chacha20poly1305.NewX(st.mac2.encryptionKey[:])
+	_, err := xchapoly.Open(cookie[:0], msg.Nonce[:], msg.Cookie[:], st.mac2.lastMAC1[:])
+
+	if err != nil {
+		return false
+	}
+
+	st.mac2.cookieSet = time.Now()
+	st.mac2.cookie = cookie
+	return true
+}
+
+func (st *CookieGenerator) AddMacs(msg []byte) {
+
+	size := len(msg)
+
+	smac2 := size - blake2s.Size128
+	smac1 := smac2 - blake2s.Size128
+
+	mac1 := msg[smac1:smac2]
+	mac2 := msg[smac2:]
+
+	st.Lock()
+	defer st.Unlock()
+
+	// set mac1
+
+	func() {
+		mac, _ := blake2s.New128(st.mac1.key[:])
+		mac.Write(msg[:smac1])
+		mac.Sum(mac1[:0])
+	}()
+	copy(st.mac2.lastMAC1[:], mac1)
+	st.mac2.hasLastMAC1 = true
+
+	// set mac2
+
+	if time.Now().Sub(st.mac2.cookieSet) > CookieRefreshTime {
+		return
+	}
+
+	func() {
+		mac, _ := blake2s.New128(st.mac2.cookie[:])
+		mac.Write(msg[:smac2])
+		mac.Sum(mac2[:0])
+	}()
+}
diff --git a/device/cookie_test.go b/device/cookie_test.go
new file mode 100644
index 0000000..79a6a86
--- /dev/null
+++ b/device/cookie_test.go
@@ -0,0 +1,191 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"testing"
+)
+
+func TestCookieMAC1(t *testing.T) {
+
+	// setup generator / checker
+
+	var (
+		generator CookieGenerator
+		checker   CookieChecker
+	)
+
+	sk, err := newPrivateKey()
+	if err != nil {
+		t.Fatal(err)
+	}
+	pk := sk.publicKey()
+
+	generator.Init(pk)
+	checker.Init(pk)
+
+	// check mac1
+
+	src := []byte{192, 168, 13, 37, 10, 10, 10}
+
+	checkMAC1 := func(msg []byte) {
+		generator.AddMacs(msg)
+		if !checker.CheckMAC1(msg) {
+			t.Fatal("MAC1 generation/verification failed")
+		}
+		if checker.CheckMAC2(msg, src) {
+			t.Fatal("MAC2 generation/verification failed")
+		}
+	}
+
+	checkMAC1([]byte{
+		0x99, 0xbb, 0xa5, 0xfc, 0x99, 0xaa, 0x83, 0xbd,
+		0x7b, 0x00, 0xc5, 0x9a, 0x4c, 0xb9, 0xcf, 0x62,
+		0x40, 0x23, 0xf3, 0x8e, 0xd8, 0xd0, 0x62, 0x64,
+		0x5d, 0xb2, 0x80, 0x13, 0xda, 0xce, 0xc6, 0x91,
+		0x61, 0xd6, 0x30, 0xf1, 0x32, 0xb3, 0xa2, 0xf4,
+		0x7b, 0x43, 0xb5, 0xa7, 0xe2, 0xb1, 0xf5, 0x6c,
+		0x74, 0x6b, 0xb0, 0xcd, 0x1f, 0x94, 0x86, 0x7b,
+		0xc8, 0xfb, 0x92, 0xed, 0x54, 0x9b, 0x44, 0xf5,
+		0xc8, 0x7d, 0xb7, 0x8e, 0xff, 0x49, 0xc4, 0xe8,
+		0x39, 0x7c, 0x19, 0xe0, 0x60, 0x19, 0x51, 0xf8,
+		0xe4, 0x8e, 0x02, 0xf1, 0x7f, 0x1d, 0xcc, 0x8e,
+		0xb0, 0x07, 0xff, 0xf8, 0xaf, 0x7f, 0x66, 0x82,
+		0x83, 0xcc, 0x7c, 0xfa, 0x80, 0xdb, 0x81, 0x53,
+		0xad, 0xf7, 0xd8, 0x0c, 0x10, 0xe0, 0x20, 0xfd,
+		0xe8, 0x0b, 0x3f, 0x90, 0x15, 0xcd, 0x93, 0xad,
+		0x0b, 0xd5, 0x0c, 0xcc, 0x88, 0x56, 0xe4, 0x3f,
+	})
+
+	checkMAC1([]byte{
+		0x33, 0xe7, 0x2a, 0x84, 0x9f, 0xff, 0x57, 0x6c,
+		0x2d, 0xc3, 0x2d, 0xe1, 0xf5, 0x5c, 0x97, 0x56,
+		0xb8, 0x93, 0xc2, 0x7d, 0xd4, 0x41, 0xdd, 0x7a,
+		0x4a, 0x59, 0x3b, 0x50, 0xdd, 0x7a, 0x7a, 0x8c,
+		0x9b, 0x96, 0xaf, 0x55, 0x3c, 0xeb, 0x6d, 0x0b,
+		0x13, 0x0b, 0x97, 0x98, 0xb3, 0x40, 0xc3, 0xcc,
+		0xb8, 0x57, 0x33, 0x45, 0x6e, 0x8b, 0x09, 0x2b,
+		0x81, 0x2e, 0xd2, 0xb9, 0x66, 0x0b, 0x93, 0x05,
+	})
+
+	checkMAC1([]byte{
+		0x9b, 0x96, 0xaf, 0x55, 0x3c, 0xeb, 0x6d, 0x0b,
+		0x13, 0x0b, 0x97, 0x98, 0xb3, 0x40, 0xc3, 0xcc,
+		0xb8, 0x57, 0x33, 0x45, 0x6e, 0x8b, 0x09, 0x2b,
+		0x81, 0x2e, 0xd2, 0xb9, 0x66, 0x0b, 0x93, 0x05,
+	})
+
+	// exchange cookie reply
+
+	func() {
+		msg := []byte{
+			0x6d, 0xd7, 0xc3, 0x2e, 0xb0, 0x76, 0xd8, 0xdf,
+			0x30, 0x65, 0x7d, 0x62, 0x3e, 0xf8, 0x9a, 0xe8,
+			0xe7, 0x3c, 0x64, 0xa3, 0x78, 0x48, 0xda, 0xf5,
+			0x25, 0x61, 0x28, 0x53, 0x79, 0x32, 0x86, 0x9f,
+			0xa0, 0x27, 0x95, 0x69, 0xb6, 0xba, 0xd0, 0xa2,
+			0xf8, 0x68, 0xea, 0xa8, 0x62, 0xf2, 0xfd, 0x1b,
+			0xe0, 0xb4, 0x80, 0xe5, 0x6b, 0x3a, 0x16, 0x9e,
+			0x35, 0xf6, 0xa8, 0xf2, 0x4f, 0x9a, 0x7b, 0xe9,
+			0x77, 0x0b, 0xc2, 0xb4, 0xed, 0xba, 0xf9, 0x22,
+			0xc3, 0x03, 0x97, 0x42, 0x9f, 0x79, 0x74, 0x27,
+			0xfe, 0xf9, 0x06, 0x6e, 0x97, 0x3a, 0xa6, 0x8f,
+			0xc9, 0x57, 0x0a, 0x54, 0x4c, 0x64, 0x4a, 0xe2,
+			0x4f, 0xa1, 0xce, 0x95, 0x9b, 0x23, 0xa9, 0x2b,
+			0x85, 0x93, 0x42, 0xb0, 0xa5, 0x53, 0xed, 0xeb,
+			0x63, 0x2a, 0xf1, 0x6d, 0x46, 0xcb, 0x2f, 0x61,
+			0x8c, 0xe1, 0xe8, 0xfa, 0x67, 0x20, 0x80, 0x6d,
+		}
+		generator.AddMacs(msg)
+		reply, err := checker.CreateReply(msg, 1377, src)
+		if err != nil {
+			t.Fatal("Failed to create cookie reply:", err)
+		}
+		if !generator.ConsumeReply(reply) {
+			t.Fatal("Failed to consume cookie reply")
+		}
+	}()
+
+	// check mac2
+
+	checkMAC2 := func(msg []byte) {
+		generator.AddMacs(msg)
+
+		if !checker.CheckMAC1(msg) {
+			t.Fatal("MAC1 generation/verification failed")
+		}
+		if !checker.CheckMAC2(msg, src) {
+			t.Fatal("MAC2 generation/verification failed")
+		}
+
+		msg[5] ^= 0x20
+
+		if checker.CheckMAC1(msg) {
+			t.Fatal("MAC1 generation/verification failed")
+		}
+		if checker.CheckMAC2(msg, src) {
+			t.Fatal("MAC2 generation/verification failed")
+		}
+
+		msg[5] ^= 0x20
+
+		srcBad1 := []byte{192, 168, 13, 37, 40, 01}
+		if checker.CheckMAC2(msg, srcBad1) {
+			t.Fatal("MAC2 generation/verification failed")
+		}
+
+		srcBad2 := []byte{192, 168, 13, 38, 40, 01}
+		if checker.CheckMAC2(msg, srcBad2) {
+			t.Fatal("MAC2 generation/verification failed")
+		}
+	}
+
+	checkMAC2([]byte{
+		0x03, 0x31, 0xb9, 0x9e, 0xb0, 0x2a, 0x54, 0xa3,
+		0xc1, 0x3f, 0xb4, 0x96, 0x16, 0xb9, 0x25, 0x15,
+		0x3d, 0x3a, 0x82, 0xf9, 0x58, 0x36, 0x86, 0x3f,
+		0x13, 0x2f, 0xfe, 0xb2, 0x53, 0x20, 0x8c, 0x3f,
+		0xba, 0xeb, 0xfb, 0x4b, 0x1b, 0x22, 0x02, 0x69,
+		0x2c, 0x90, 0xbc, 0xdc, 0xcf, 0xcf, 0x85, 0xeb,
+		0x62, 0x66, 0x6f, 0xe8, 0xe1, 0xa6, 0xa8, 0x4c,
+		0xa0, 0x04, 0x23, 0x15, 0x42, 0xac, 0xfa, 0x38,
+	})
+
+	checkMAC2([]byte{
+		0x0e, 0x2f, 0x0e, 0xa9, 0x29, 0x03, 0xe1, 0xf3,
+		0x24, 0x01, 0x75, 0xad, 0x16, 0xa5, 0x66, 0x85,
+		0xca, 0x66, 0xe0, 0xbd, 0xc6, 0x34, 0xd8, 0x84,
+		0x09, 0x9a, 0x58, 0x14, 0xfb, 0x05, 0xda, 0xf5,
+		0x90, 0xf5, 0x0c, 0x4e, 0x22, 0x10, 0xc9, 0x85,
+		0x0f, 0xe3, 0x77, 0x35, 0xe9, 0x6b, 0xc2, 0x55,
+		0x32, 0x46, 0xae, 0x25, 0xe0, 0xe3, 0x37, 0x7a,
+		0x4b, 0x71, 0xcc, 0xfc, 0x91, 0xdf, 0xd6, 0xca,
+		0xfe, 0xee, 0xce, 0x3f, 0x77, 0xa2, 0xfd, 0x59,
+		0x8e, 0x73, 0x0a, 0x8d, 0x5c, 0x24, 0x14, 0xca,
+		0x38, 0x91, 0xb8, 0x2c, 0x8c, 0xa2, 0x65, 0x7b,
+		0xbc, 0x49, 0xbc, 0xb5, 0x58, 0xfc, 0xe3, 0xd7,
+		0x02, 0xcf, 0xf7, 0x4c, 0x60, 0x91, 0xed, 0x55,
+		0xe9, 0xf9, 0xfe, 0xd1, 0x44, 0x2c, 0x75, 0xf2,
+		0xb3, 0x5d, 0x7b, 0x27, 0x56, 0xc0, 0x48, 0x4f,
+		0xb0, 0xba, 0xe4, 0x7d, 0xd0, 0xaa, 0xcd, 0x3d,
+		0xe3, 0x50, 0xd2, 0xcf, 0xb9, 0xfa, 0x4b, 0x2d,
+		0xc6, 0xdf, 0x3b, 0x32, 0x98, 0x45, 0xe6, 0x8f,
+		0x1c, 0x5c, 0xa2, 0x20, 0x7d, 0x1c, 0x28, 0xc2,
+		0xd4, 0xa1, 0xe0, 0x21, 0x52, 0x8f, 0x1c, 0xd0,
+		0x62, 0x97, 0x48, 0xbb, 0xf4, 0xa9, 0xcb, 0x35,
+		0xf2, 0x07, 0xd3, 0x50, 0xd8, 0xa9, 0xc5, 0x9a,
+		0x0f, 0xbd, 0x37, 0xaf, 0xe1, 0x45, 0x19, 0xee,
+		0x41, 0xf3, 0xf7, 0xe5, 0xe0, 0x30, 0x3f, 0xbe,
+		0x3d, 0x39, 0x64, 0x00, 0x7a, 0x1a, 0x51, 0x5e,
+		0xe1, 0x70, 0x0b, 0xb9, 0x77, 0x5a, 0xf0, 0xc4,
+		0x8a, 0xa1, 0x3a, 0x77, 0x1a, 0xe0, 0xc2, 0x06,
+		0x91, 0xd5, 0xe9, 0x1c, 0xd3, 0xfe, 0xab, 0x93,
+		0x1a, 0x0a, 0x4c, 0xbb, 0xf0, 0xff, 0xdc, 0xaa,
+		0x61, 0x73, 0xcb, 0x03, 0x4b, 0x71, 0x68, 0x64,
+		0x3d, 0x82, 0x31, 0x41, 0xd7, 0x8b, 0x22, 0x7b,
+		0x7d, 0xa1, 0xd5, 0x85, 0x6d, 0xf0, 0x1b, 0xaa,
+	})
+}
diff --git a/device/device.go b/device/device.go
new file mode 100644
index 0000000..d6c96d6
--- /dev/null
+++ b/device/device.go
@@ -0,0 +1,396 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"golang.zx2c4.com/wireguard/ratelimiter"
+	"golang.zx2c4.com/wireguard/tun"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+const (
+	DeviceRoutineNumberPerCPU     = 3
+	DeviceRoutineNumberAdditional = 2
+)
+
+type Device struct {
+	isUp     AtomicBool // device is (going) up
+	isClosed AtomicBool // device is closed? (acting as guard)
+	log      *Logger
+
+	// synchronized resources (locks acquired in order)
+
+	state struct {
+		starting sync.WaitGroup
+		stopping sync.WaitGroup
+		sync.Mutex
+		changing AtomicBool
+		current  bool
+	}
+
+	net struct {
+		starting sync.WaitGroup
+		stopping sync.WaitGroup
+		sync.RWMutex
+		bind   Bind   // bind interface
+		port   uint16 // listening port
+		fwmark uint32 // mark value (0 = disabled)
+	}
+
+	staticIdentity struct {
+		sync.RWMutex
+		privateKey NoisePrivateKey
+		publicKey  NoisePublicKey
+	}
+
+	peers struct {
+		sync.RWMutex
+		keyMap map[NoisePublicKey]*Peer
+	}
+
+	// unprotected / "self-synchronising resources"
+
+	allowedips    AllowedIPs
+	indexTable    IndexTable
+	cookieChecker CookieChecker
+
+	rate struct {
+		underLoadUntil atomic.Value
+		limiter        ratelimiter.Ratelimiter
+	}
+
+	pool struct {
+		messageBufferPool        *sync.Pool
+		messageBufferReuseChan   chan *[MaxMessageSize]byte
+		inboundElementPool       *sync.Pool
+		inboundElementReuseChan  chan *QueueInboundElement
+		outboundElementPool      *sync.Pool
+		outboundElementReuseChan chan *QueueOutboundElement
+	}
+
+	queue struct {
+		encryption chan *QueueOutboundElement
+		decryption chan *QueueInboundElement
+		handshake  chan QueueHandshakeElement
+	}
+
+	signals struct {
+		stop chan struct{}
+	}
+
+	tun struct {
+		device tun.TUNDevice
+		mtu    int32
+	}
+}
+
+/* Converts the peer into a "zombie", which remains in the peer map,
+ * but processes no packets and does not exists in the routing table.
+ *
+ * Must hold device.peers.Mutex
+ */
+func unsafeRemovePeer(device *Device, peer *Peer, key NoisePublicKey) {
+
+	// stop routing and processing of packets
+
+	device.allowedips.RemoveByPeer(peer)
+	peer.Stop()
+
+	// remove from peer map
+
+	delete(device.peers.keyMap, key)
+}
+
+func deviceUpdateState(device *Device) {
+
+	// check if state already being updated (guard)
+
+	if device.state.changing.Swap(true) {
+		return
+	}
+
+	// compare to current state of device
+
+	device.state.Lock()
+
+	newIsUp := device.isUp.Get()
+
+	if newIsUp == device.state.current {
+		device.state.changing.Set(false)
+		device.state.Unlock()
+		return
+	}
+
+	// change state of device
+
+	switch newIsUp {
+	case true:
+		if err := device.BindUpdate(); err != nil {
+			device.isUp.Set(false)
+			break
+		}
+		device.peers.RLock()
+		for _, peer := range device.peers.keyMap {
+			peer.Start()
+			if peer.persistentKeepaliveInterval > 0 {
+				peer.SendKeepalive()
+			}
+		}
+		device.peers.RUnlock()
+
+	case false:
+		device.BindClose()
+		device.peers.RLock()
+		for _, peer := range device.peers.keyMap {
+			peer.Stop()
+		}
+		device.peers.RUnlock()
+	}
+
+	// update state variables
+
+	device.state.current = newIsUp
+	device.state.changing.Set(false)
+	device.state.Unlock()
+
+	// check for state change in the mean time
+
+	deviceUpdateState(device)
+}
+
+func (device *Device) Up() {
+
+	// closed device cannot be brought up
+
+	if device.isClosed.Get() {
+		return
+	}
+
+	device.isUp.Set(true)
+	deviceUpdateState(device)
+}
+
+func (device *Device) Down() {
+	device.isUp.Set(false)
+	deviceUpdateState(device)
+}
+
+func (device *Device) IsUnderLoad() bool {
+
+	// check if currently under load
+
+	now := time.Now()
+	underLoad := len(device.queue.handshake) >= UnderLoadQueueSize
+	if underLoad {
+		device.rate.underLoadUntil.Store(now.Add(UnderLoadAfterTime))
+		return true
+	}
+
+	// check if recently under load
+
+	until := device.rate.underLoadUntil.Load().(time.Time)
+	return until.After(now)
+}
+
+func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
+
+	// lock required resources
+
+	device.staticIdentity.Lock()
+	defer device.staticIdentity.Unlock()
+
+	device.peers.Lock()
+	defer device.peers.Unlock()
+
+	for _, peer := range device.peers.keyMap {
+		peer.handshake.mutex.RLock()
+		defer peer.handshake.mutex.RUnlock()
+	}
+
+	// remove peers with matching public keys
+
+	publicKey := sk.publicKey()
+	for key, peer := range device.peers.keyMap {
+		if peer.handshake.remoteStatic.Equals(publicKey) {
+			unsafeRemovePeer(device, peer, key)
+		}
+	}
+
+	// update key material
+
+	device.staticIdentity.privateKey = sk
+	device.staticIdentity.publicKey = publicKey
+	device.cookieChecker.Init(publicKey)
+
+	// do static-static DH pre-computations
+
+	rmKey := device.staticIdentity.privateKey.IsZero()
+
+	for key, peer := range device.peers.keyMap {
+
+		handshake := &peer.handshake
+
+		if rmKey {
+			handshake.precomputedStaticStatic = [NoisePublicKeySize]byte{}
+		} else {
+			handshake.precomputedStaticStatic = device.staticIdentity.privateKey.sharedSecret(handshake.remoteStatic)
+		}
+
+		if isZero(handshake.precomputedStaticStatic[:]) {
+			unsafeRemovePeer(device, peer, key)
+		}
+	}
+
+	return nil
+}
+
+func NewDevice(tunDevice tun.TUNDevice, logger *Logger) *Device {
+	device := new(Device)
+
+	device.isUp.Set(false)
+	device.isClosed.Set(false)
+
+	device.log = logger
+
+	device.tun.device = tunDevice
+	mtu, err := device.tun.device.MTU()
+	if err != nil {
+		logger.Error.Println("Trouble determining MTU, assuming default:", err)
+		mtu = DefaultMTU
+	}
+	device.tun.mtu = int32(mtu)
+
+	device.peers.keyMap = make(map[NoisePublicKey]*Peer)
+
+	device.rate.limiter.Init()
+	device.rate.underLoadUntil.Store(time.Time{})
+
+	device.indexTable.Init()
+	device.allowedips.Reset()
+
+	device.PopulatePools()
+
+	// create queues
+
+	device.queue.handshake = make(chan QueueHandshakeElement, QueueHandshakeSize)
+	device.queue.encryption = make(chan *QueueOutboundElement, QueueOutboundSize)
+	device.queue.decryption = make(chan *QueueInboundElement, QueueInboundSize)
+
+	// prepare signals
+
+	device.signals.stop = make(chan struct{})
+
+	// prepare net
+
+	device.net.port = 0
+	device.net.bind = nil
+
+	// start workers
+
+	cpus := runtime.NumCPU()
+	device.state.starting.Wait()
+	device.state.stopping.Wait()
+	device.state.stopping.Add(DeviceRoutineNumberPerCPU*cpus + DeviceRoutineNumberAdditional)
+	device.state.starting.Add(DeviceRoutineNumberPerCPU*cpus + DeviceRoutineNumberAdditional)
+	for i := 0; i < cpus; i += 1 {
+		go device.RoutineEncryption()
+		go device.RoutineDecryption()
+		go device.RoutineHandshake()
+	}
+
+	go device.RoutineReadFromTUN()
+	go device.RoutineTUNEventReader()
+
+	device.state.starting.Wait()
+
+	return device
+}
+
+func (device *Device) LookupPeer(pk NoisePublicKey) *Peer {
+	device.peers.RLock()
+	defer device.peers.RUnlock()
+
+	return device.peers.keyMap[pk]
+}
+
+func (device *Device) RemovePeer(key NoisePublicKey) {
+	device.peers.Lock()
+	defer device.peers.Unlock()
+
+	// stop peer and remove from routing
+
+	peer, ok := device.peers.keyMap[key]
+	if ok {
+		unsafeRemovePeer(device, peer, key)
+	}
+}
+
+func (device *Device) RemoveAllPeers() {
+	device.peers.Lock()
+	defer device.peers.Unlock()
+
+	for key, peer := range device.peers.keyMap {
+		unsafeRemovePeer(device, peer, key)
+	}
+
+	device.peers.keyMap = make(map[NoisePublicKey]*Peer)
+}
+
+func (device *Device) FlushPacketQueues() {
+	for {
+		select {
+		case elem, ok := <-device.queue.decryption:
+			if ok {
+				elem.Drop()
+			}
+		case elem, ok := <-device.queue.encryption:
+			if ok {
+				elem.Drop()
+			}
+		case <-device.queue.handshake:
+		default:
+			return
+		}
+	}
+
+}
+
+func (device *Device) Close() {
+	if device.isClosed.Swap(true) {
+		return
+	}
+
+	device.state.starting.Wait()
+
+	device.log.Info.Println("Device closing")
+	device.state.changing.Set(true)
+	device.state.Lock()
+	defer device.state.Unlock()
+
+	device.tun.device.Close()
+	device.BindClose()
+
+	device.isUp.Set(false)
+
+	close(device.signals.stop)
+
+	device.RemoveAllPeers()
+
+	device.state.stopping.Wait()
+	device.FlushPacketQueues()
+
+	device.rate.limiter.Close()
+
+	device.state.changing.Set(false)
+	device.log.Info.Println("Interface closed")
+}
+
+func (device *Device) Wait() chan struct{} {
+	return device.signals.stop
+}
diff --git a/device/device_test.go b/device/device_test.go
new file mode 100644
index 0000000..db5a3c0
--- /dev/null
+++ b/device/device_test.go
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+/* Create two device instances and simulate full WireGuard interaction
+ * without network dependencies
+ */
+
+import "testing"
+
+func TestDevice(t *testing.T) {
+
+	// prepare tun devices for generating traffic
+
+	tun1, err := CreateDummyTUN("tun1")
+	if err != nil {
+		t.Error("failed to create tun:", err.Error())
+	}
+
+	tun2, err := CreateDummyTUN("tun2")
+	if err != nil {
+		t.Error("failed to create tun:", err.Error())
+	}
+
+	_ = tun1
+	_ = tun2
+
+	// prepare endpoints
+
+	end1, err := CreateDummyEndpoint()
+	if err != nil {
+		t.Error("failed to create endpoint:", err.Error())
+	}
+
+	end2, err := CreateDummyEndpoint()
+	if err != nil {
+		t.Error("failed to create endpoint:", err.Error())
+	}
+
+	_ = end1
+	_ = end2
+
+	// create binds
+
+}
diff --git a/device/endpoint_test.go b/device/endpoint_test.go
new file mode 100644
index 0000000..1896790
--- /dev/null
+++ b/device/endpoint_test.go
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"math/rand"
+	"net"
+)
+
+type DummyEndpoint struct {
+	src [16]byte
+	dst [16]byte
+}
+
+func CreateDummyEndpoint() (*DummyEndpoint, error) {
+	var end DummyEndpoint
+	if _, err := rand.Read(end.src[:]); err != nil {
+		return nil, err
+	}
+	_, err := rand.Read(end.dst[:])
+	return &end, err
+}
+
+func (e *DummyEndpoint) ClearSrc() {}
+
+func (e *DummyEndpoint) SrcToString() string {
+	var addr net.UDPAddr
+	addr.IP = e.SrcIP()
+	addr.Port = 1000
+	return addr.String()
+}
+
+func (e *DummyEndpoint) DstToString() string {
+	var addr net.UDPAddr
+	addr.IP = e.DstIP()
+	addr.Port = 1000
+	return addr.String()
+}
+
+func (e *DummyEndpoint) SrcToBytes() []byte {
+	return e.src[:]
+}
+
+func (e *DummyEndpoint) DstIP() net.IP {
+	return e.dst[:]
+}
+
+func (e *DummyEndpoint) SrcIP() net.IP {
+	return e.src[:]
+}
diff --git a/device/indextable.go b/device/indextable.go
new file mode 100644
index 0000000..4cba970
--- /dev/null
+++ b/device/indextable.go
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"crypto/rand"
+	"sync"
+	"unsafe"
+)
+
+type IndexTableEntry struct {
+	peer      *Peer
+	handshake *Handshake
+	keypair   *Keypair
+}
+
+type IndexTable struct {
+	sync.RWMutex
+	table map[uint32]IndexTableEntry
+}
+
+func randUint32() (uint32, error) {
+	var integer [4]byte
+	_, err := rand.Read(integer[:])
+	return *(*uint32)(unsafe.Pointer(&integer[0])), err
+}
+
+func (table *IndexTable) Init() {
+	table.Lock()
+	defer table.Unlock()
+	table.table = make(map[uint32]IndexTableEntry)
+}
+
+func (table *IndexTable) Delete(index uint32) {
+	table.Lock()
+	defer table.Unlock()
+	delete(table.table, index)
+}
+
+func (table *IndexTable) SwapIndexForKeypair(index uint32, keypair *Keypair) {
+	table.Lock()
+	defer table.Unlock()
+	entry, ok := table.table[index]
+	if !ok {
+		return
+	}
+	table.table[index] = IndexTableEntry{
+		peer:      entry.peer,
+		keypair:   keypair,
+		handshake: nil,
+	}
+}
+
+func (table *IndexTable) NewIndexForHandshake(peer *Peer, handshake *Handshake) (uint32, error) {
+	for {
+		// generate random index
+
+		index, err := randUint32()
+		if err != nil {
+			return index, err
+		}
+
+		// check if index used
+
+		table.RLock()
+		_, ok := table.table[index]
+		table.RUnlock()
+		if ok {
+			continue
+		}
+
+		// check again while locked
+
+		table.Lock()
+		_, found := table.table[index]
+		if found {
+			table.Unlock()
+			continue
+		}
+		table.table[index] = IndexTableEntry{
+			peer:      peer,
+			handshake: handshake,
+			keypair:   nil,
+		}
+		table.Unlock()
+		return index, nil
+	}
+}
+
+func (table *IndexTable) Lookup(id uint32) IndexTableEntry {
+	table.RLock()
+	defer table.RUnlock()
+	return table.table[id]
+}
diff --git a/device/ip.go b/device/ip.go
new file mode 100644
index 0000000..9d4fb74
--- /dev/null
+++ b/device/ip.go
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"net"
+)
+
+const (
+	IPv4offsetTotalLength = 2
+	IPv4offsetSrc         = 12
+	IPv4offsetDst         = IPv4offsetSrc + net.IPv4len
+)
+
+const (
+	IPv6offsetPayloadLength = 4
+	IPv6offsetSrc           = 8
+	IPv6offsetDst           = IPv6offsetSrc + net.IPv6len
+)
diff --git a/device/kdf_test.go b/device/kdf_test.go
new file mode 100644
index 0000000..11ea8d5
--- /dev/null
+++ b/device/kdf_test.go
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"encoding/hex"
+	"golang.org/x/crypto/blake2s"
+	"testing"
+)
+
+type KDFTest struct {
+	key   string
+	input string
+	t0    string
+	t1    string
+	t2    string
+}
+
+func assertEquals(t *testing.T, a string, b string) {
+	if a != b {
+		t.Fatal("expected", a, "=", b)
+	}
+}
+
+func TestKDF(t *testing.T) {
+	tests := []KDFTest{
+		{
+			key:   "746573742d6b6579",
+			input: "746573742d696e707574",
+			t0:    "6f0e5ad38daba1bea8a0d213688736f19763239305e0f58aba697f9ffc41c633",
+			t1:    "df1194df20802a4fe594cde27e92991c8cae66c366e8106aaa937a55fa371e8a",
+			t2:    "fac6e2745a325f5dc5d11a5b165aad08b0ada28e7b4e666b7c077934a4d76c24",
+		},
+		{
+			key:   "776972656775617264",
+			input: "776972656775617264",
+			t0:    "491d43bbfdaa8750aaf535e334ecbfe5129967cd64635101c566d4caefda96e8",
+			t1:    "1e71a379baefd8a79aa4662212fcafe19a23e2b609a3db7d6bcba8f560e3d25f",
+			t2:    "31e1ae48bddfbe5de38f295e5452b1909a1b4e38e183926af3780b0c1e1f0160",
+		},
+		{
+			key:   "",
+			input: "",
+			t0:    "8387b46bf43eccfcf349552a095d8315c4055beb90208fb1be23b894bc2ed5d0",
+			t1:    "58a0e5f6faefccf4807bff1f05fa8a9217945762040bcec2f4b4a62bdfe0e86e",
+			t2:    "0ce6ea98ec548f8e281e93e32db65621c45eb18dc6f0a7ad94178610a2f7338e",
+		},
+	}
+
+	var t0, t1, t2 [blake2s.Size]byte
+
+	for _, test := range tests {
+		key, _ := hex.DecodeString(test.key)
+		input, _ := hex.DecodeString(test.input)
+		KDF3(&t0, &t1, &t2, key, input)
+		t0s := hex.EncodeToString(t0[:])
+		t1s := hex.EncodeToString(t1[:])
+		t2s := hex.EncodeToString(t2[:])
+		assertEquals(t, t0s, test.t0)
+		assertEquals(t, t1s, test.t1)
+		assertEquals(t, t2s, test.t2)
+	}
+
+	for _, test := range tests {
+		key, _ := hex.DecodeString(test.key)
+		input, _ := hex.DecodeString(test.input)
+		KDF2(&t0, &t1, key, input)
+		t0s := hex.EncodeToString(t0[:])
+		t1s := hex.EncodeToString(t1[:])
+		assertEquals(t, t0s, test.t0)
+		assertEquals(t, t1s, test.t1)
+	}
+
+	for _, test := range tests {
+		key, _ := hex.DecodeString(test.key)
+		input, _ := hex.DecodeString(test.input)
+		KDF1(&t0, key, input)
+		t0s := hex.EncodeToString(t0[:])
+		assertEquals(t, t0s, test.t0)
+	}
+}
diff --git a/device/keypair.go b/device/keypair.go
new file mode 100644
index 0000000..a9fbfce
--- /dev/null
+++ b/device/keypair.go
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"crypto/cipher"
+	"golang.zx2c4.com/wireguard/replay"
+	"sync"
+	"time"
+)
+
+/* Due to limitations in Go and /x/crypto there is currently
+ * no way to ensure that key material is securely ereased in memory.
+ *
+ * Since this may harm the forward secrecy property,
+ * we plan to resolve this issue; whenever Go allows us to do so.
+ */
+
+type Keypair struct {
+	sendNonce    uint64
+	send         cipher.AEAD
+	receive      cipher.AEAD
+	replayFilter replay.ReplayFilter
+	isInitiator  bool
+	created      time.Time
+	localIndex   uint32
+	remoteIndex  uint32
+}
+
+type Keypairs struct {
+	sync.RWMutex
+	current  *Keypair
+	previous *Keypair
+	next     *Keypair
+}
+
+func (kp *Keypairs) Current() *Keypair {
+	kp.RLock()
+	defer kp.RUnlock()
+	return kp.current
+}
+
+func (device *Device) DeleteKeypair(key *Keypair) {
+	if key != nil {
+		device.indexTable.Delete(key.localIndex)
+	}
+}
diff --git a/device/logger.go b/device/logger.go
new file mode 100644
index 0000000..7c8b704
--- /dev/null
+++ b/device/logger.go
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+)
+
+const (
+	LogLevelSilent = iota
+	LogLevelError
+	LogLevelInfo
+	LogLevelDebug
+)
+
+type Logger struct {
+	Debug *log.Logger
+	Info  *log.Logger
+	Error *log.Logger
+}
+
+func NewLogger(level int, prepend string) *Logger {
+	output := os.Stdout
+	logger := new(Logger)
+
+	logErr, logInfo, logDebug := func() (io.Writer, io.Writer, io.Writer) {
+		if level >= LogLevelDebug {
+			return output, output, output
+		}
+		if level >= LogLevelInfo {
+			return output, output, ioutil.Discard
+		}
+		if level >= LogLevelError {
+			return output, ioutil.Discard, ioutil.Discard
+		}
+		return ioutil.Discard, ioutil.Discard, ioutil.Discard
+	}()
+
+	logger.Debug = log.New(logDebug,
+		"DEBUG: "+prepend,
+		log.Ldate|log.Ltime,
+	)
+
+	logger.Info = log.New(logInfo,
+		"INFO: "+prepend,
+		log.Ldate|log.Ltime,
+	)
+	logger.Error = log.New(logErr,
+		"ERROR: "+prepend,
+		log.Ldate|log.Ltime,
+	)
+	return logger
+}
diff --git a/device/mark_default.go b/device/mark_default.go
new file mode 100644
index 0000000..76b1015
--- /dev/null
+++ b/device/mark_default.go
@@ -0,0 +1,12 @@
+// +build !linux,!openbsd,!freebsd
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+func (bind *NativeBind) SetMark(mark uint32) error {
+	return nil
+}
diff --git a/device/mark_unix.go b/device/mark_unix.go
new file mode 100644
index 0000000..ee64cc9
--- /dev/null
+++ b/device/mark_unix.go
@@ -0,0 +1,64 @@
+// +build android openbsd freebsd
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"golang.org/x/sys/unix"
+	"runtime"
+)
+
+var fwmarkIoctl int
+
+func init() {
+	switch runtime.GOOS {
+	case "linux", "android":
+		fwmarkIoctl = 36 /* unix.SO_MARK */
+	case "freebsd":
+		fwmarkIoctl = 0x1015 /* unix.SO_USER_COOKIE */
+	case "openbsd":
+		fwmarkIoctl = 0x1021 /* unix.SO_RTABLE */
+	}
+}
+
+func (bind *NativeBind) SetMark(mark uint32) error {
+	var operr error
+	if fwmarkIoctl == 0 {
+		return nil
+	}
+	if bind.ipv4 != nil {
+		fd, err := bind.ipv4.SyscallConn()
+		if err != nil {
+			return err
+		}
+		err = fd.Control(func(fd uintptr) {
+			operr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, fwmarkIoctl, int(mark))
+		})
+		if err == nil {
+			err = operr
+		}
+		if err != nil {
+			return err
+		}
+	}
+	if bind.ipv6 != nil {
+		fd, err := bind.ipv6.SyscallConn()
+		if err != nil {
+			return err
+		}
+		err = fd.Control(func(fd uintptr) {
+			operr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, fwmarkIoctl, int(mark))
+		})
+		if err == nil {
+			err = operr
+		}
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
diff --git a/device/misc.go b/device/misc.go
new file mode 100644
index 0000000..a38d1c1
--- /dev/null
+++ b/device/misc.go
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"sync/atomic"
+)
+
+/* Atomic Boolean */
+
+const (
+	AtomicFalse = int32(iota)
+	AtomicTrue
+)
+
+type AtomicBool struct {
+	int32
+}
+
+func (a *AtomicBool) Get() bool {
+	return atomic.LoadInt32(&a.int32) == AtomicTrue
+}
+
+func (a *AtomicBool) Swap(val bool) bool {
+	flag := AtomicFalse
+	if val {
+		flag = AtomicTrue
+	}
+	return atomic.SwapInt32(&a.int32, flag) == AtomicTrue
+}
+
+func (a *AtomicBool) Set(val bool) {
+	flag := AtomicFalse
+	if val {
+		flag = AtomicTrue
+	}
+	atomic.StoreInt32(&a.int32, flag)
+}
+
+func min(a, b uint) uint {
+	if a > b {
+		return b
+	}
+	return a
+}
diff --git a/device/noise-helpers.go b/device/noise-helpers.go
new file mode 100644
index 0000000..4b09bf3
--- /dev/null
+++ b/device/noise-helpers.go
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/subtle"
+	"golang.org/x/crypto/blake2s"
+	"golang.org/x/crypto/curve25519"
+	"hash"
+)
+
+/* KDF related functions.
+ * HMAC-based Key Derivation Function (HKDF)
+ * https://tools.ietf.org/html/rfc5869
+ */
+
+func HMAC1(sum *[blake2s.Size]byte, key, in0 []byte) {
+	mac := hmac.New(func() hash.Hash {
+		h, _ := blake2s.New256(nil)
+		return h
+	}, key)
+	mac.Write(in0)
+	mac.Sum(sum[:0])
+}
+
+func HMAC2(sum *[blake2s.Size]byte, key, in0, in1 []byte) {
+	mac := hmac.New(func() hash.Hash {
+		h, _ := blake2s.New256(nil)
+		return h
+	}, key)
+	mac.Write(in0)
+	mac.Write(in1)
+	mac.Sum(sum[:0])
+}
+
+func KDF1(t0 *[blake2s.Size]byte, key, input []byte) {
+	HMAC1(t0, key, input)
+	HMAC1(t0, t0[:], []byte{0x1})
+	return
+}
+
+func KDF2(t0, t1 *[blake2s.Size]byte, key, input []byte) {
+	var prk [blake2s.Size]byte
+	HMAC1(&prk, key, input)
+	HMAC1(t0, prk[:], []byte{0x1})
+	HMAC2(t1, prk[:], t0[:], []byte{0x2})
+	setZero(prk[:])
+	return
+}
+
+func KDF3(t0, t1, t2 *[blake2s.Size]byte, key, input []byte) {
+	var prk [blake2s.Size]byte
+	HMAC1(&prk, key, input)
+	HMAC1(t0, prk[:], []byte{0x1})
+	HMAC2(t1, prk[:], t0[:], []byte{0x2})
+	HMAC2(t2, prk[:], t1[:], []byte{0x3})
+	setZero(prk[:])
+	return
+}
+
+func isZero(val []byte) bool {
+	acc := 1
+	for _, b := range val {
+		acc &= subtle.ConstantTimeByteEq(b, 0)
+	}
+	return acc == 1
+}
+
+/* This function is not used as pervasively as it should because this is mostly impossible in Go at the moment */
+func setZero(arr []byte) {
+	for i := range arr {
+		arr[i] = 0
+	}
+}
+
+func (sk *NoisePrivateKey) clamp() {
+	sk[0] &= 248
+	sk[31] = (sk[31] & 127) | 64
+}
+
+func newPrivateKey() (sk NoisePrivateKey, err error) {
+	_, err = rand.Read(sk[:])
+	sk.clamp()
+	return
+}
+
+func (sk *NoisePrivateKey) publicKey() (pk NoisePublicKey) {
+	apk := (*[NoisePublicKeySize]byte)(&pk)
+	ask := (*[NoisePrivateKeySize]byte)(sk)
+	curve25519.ScalarBaseMult(apk, ask)
+	return
+}
+
+func (sk *NoisePrivateKey) sharedSecret(pk NoisePublicKey) (ss [NoisePublicKeySize]byte) {
+	apk := (*[NoisePublicKeySize]byte)(&pk)
+	ask := (*[NoisePrivateKeySize]byte)(sk)
+	curve25519.ScalarMult(&ss, ask, apk)
+	return ss
+}
diff --git a/device/noise-protocol.go b/device/noise-protocol.go
new file mode 100644
index 0000000..73826e1
--- /dev/null
+++ b/device/noise-protocol.go
@@ -0,0 +1,600 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"errors"
+	"golang.org/x/crypto/blake2s"
+	"golang.org/x/crypto/chacha20poly1305"
+	"golang.org/x/crypto/poly1305"
+	"golang.zx2c4.com/wireguard/tai64n"
+	"sync"
+	"time"
+)
+
+const (
+	HandshakeZeroed = iota
+	HandshakeInitiationCreated
+	HandshakeInitiationConsumed
+	HandshakeResponseCreated
+	HandshakeResponseConsumed
+)
+
+const (
+	NoiseConstruction = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"
+	WGIdentifier      = "WireGuard v1 zx2c4 Jason@zx2c4.com"
+	WGLabelMAC1       = "mac1----"
+	WGLabelCookie     = "cookie--"
+)
+
+const (
+	MessageInitiationType  = 1
+	MessageResponseType    = 2
+	MessageCookieReplyType = 3
+	MessageTransportType   = 4
+)
+
+const (
+	MessageInitiationSize      = 148                                           // size of handshake initation message
+	MessageResponseSize        = 92                                            // size of response message
+	MessageCookieReplySize     = 64                                            // size of cookie reply message
+	MessageTransportHeaderSize = 16                                            // size of data preceeding content in transport message
+	MessageTransportSize       = MessageTransportHeaderSize + poly1305.TagSize // size of empty transport
+	MessageKeepaliveSize       = MessageTransportSize                          // size of keepalive
+	MessageHandshakeSize       = MessageInitiationSize                         // size of largest handshake releated message
+)
+
+const (
+	MessageTransportOffsetReceiver = 4
+	MessageTransportOffsetCounter  = 8
+	MessageTransportOffsetContent  = 16
+)
+
+/* Type is an 8-bit field, followed by 3 nul bytes,
+ * by marshalling the messages in little-endian byteorder
+ * we can treat these as a 32-bit unsigned int (for now)
+ *
+ */
+
+type MessageInitiation struct {
+	Type      uint32
+	Sender    uint32
+	Ephemeral NoisePublicKey
+	Static    [NoisePublicKeySize + poly1305.TagSize]byte
+	Timestamp [tai64n.TimestampSize + poly1305.TagSize]byte
+	MAC1      [blake2s.Size128]byte
+	MAC2      [blake2s.Size128]byte
+}
+
+type MessageResponse struct {
+	Type      uint32
+	Sender    uint32
+	Receiver  uint32
+	Ephemeral NoisePublicKey
+	Empty     [poly1305.TagSize]byte
+	MAC1      [blake2s.Size128]byte
+	MAC2      [blake2s.Size128]byte
+}
+
+type MessageTransport struct {
+	Type     uint32
+	Receiver uint32
+	Counter  uint64
+	Content  []byte
+}
+
+type MessageCookieReply struct {
+	Type     uint32
+	Receiver uint32
+	Nonce    [chacha20poly1305.NonceSizeX]byte
+	Cookie   [blake2s.Size128 + poly1305.TagSize]byte
+}
+
+type Handshake struct {
+	state                     int
+	mutex                     sync.RWMutex
+	hash                      [blake2s.Size]byte       // hash value
+	chainKey                  [blake2s.Size]byte       // chain key
+	presharedKey              NoiseSymmetricKey        // psk
+	localEphemeral            NoisePrivateKey          // ephemeral secret key
+	localIndex                uint32                   // used to clear hash-table
+	remoteIndex               uint32                   // index for sending
+	remoteStatic              NoisePublicKey           // long term key
+	remoteEphemeral           NoisePublicKey           // ephemeral public key
+	precomputedStaticStatic   [NoisePublicKeySize]byte // precomputed shared secret
+	lastTimestamp             tai64n.Timestamp
+	lastInitiationConsumption time.Time
+	lastSentHandshake         time.Time
+}
+
+var (
+	InitialChainKey [blake2s.Size]byte
+	InitialHash     [blake2s.Size]byte
+	ZeroNonce       [chacha20poly1305.NonceSize]byte
+)
+
+func mixKey(dst *[blake2s.Size]byte, c *[blake2s.Size]byte, data []byte) {
+	KDF1(dst, c[:], data)
+}
+
+func mixHash(dst *[blake2s.Size]byte, h *[blake2s.Size]byte, data []byte) {
+	hash, _ := blake2s.New256(nil)
+	hash.Write(h[:])
+	hash.Write(data)
+	hash.Sum(dst[:0])
+	hash.Reset()
+}
+
+func (h *Handshake) Clear() {
+	setZero(h.localEphemeral[:])
+	setZero(h.remoteEphemeral[:])
+	setZero(h.chainKey[:])
+	setZero(h.hash[:])
+	h.localIndex = 0
+	h.state = HandshakeZeroed
+}
+
+func (h *Handshake) mixHash(data []byte) {
+	mixHash(&h.hash, &h.hash, data)
+}
+
+func (h *Handshake) mixKey(data []byte) {
+	mixKey(&h.chainKey, &h.chainKey, data)
+}
+
+/* Do basic precomputations
+ */
+func init() {
+	InitialChainKey = blake2s.Sum256([]byte(NoiseConstruction))
+	mixHash(&InitialHash, &InitialChainKey, []byte(WGIdentifier))
+}
+
+func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, error) {
+
+	device.staticIdentity.RLock()
+	defer device.staticIdentity.RUnlock()
+
+	handshake := &peer.handshake
+	handshake.mutex.Lock()
+	defer handshake.mutex.Unlock()
+
+	if isZero(handshake.precomputedStaticStatic[:]) {
+		return nil, errors.New("static shared secret is zero")
+	}
+
+	// create ephemeral key
+
+	var err error
+	handshake.hash = InitialHash
+	handshake.chainKey = InitialChainKey
+	handshake.localEphemeral, err = newPrivateKey()
+	if err != nil {
+		return nil, err
+	}
+
+	// assign index
+
+	device.indexTable.Delete(handshake.localIndex)
+	handshake.localIndex, err = device.indexTable.NewIndexForHandshake(peer, handshake)
+
+	if err != nil {
+		return nil, err
+	}
+
+	handshake.mixHash(handshake.remoteStatic[:])
+
+	msg := MessageInitiation{
+		Type:      MessageInitiationType,
+		Ephemeral: handshake.localEphemeral.publicKey(),
+		Sender:    handshake.localIndex,
+	}
+
+	handshake.mixKey(msg.Ephemeral[:])
+	handshake.mixHash(msg.Ephemeral[:])
+
+	// encrypt static key
+
+	func() {
+		var key [chacha20poly1305.KeySize]byte
+		ss := handshake.localEphemeral.sharedSecret(handshake.remoteStatic)
+		KDF2(
+			&handshake.chainKey,
+			&key,
+			handshake.chainKey[:],
+			ss[:],
+		)
+		aead, _ := chacha20poly1305.New(key[:])
+		aead.Seal(msg.Static[:0], ZeroNonce[:], device.staticIdentity.publicKey[:], handshake.hash[:])
+	}()
+	handshake.mixHash(msg.Static[:])
+
+	// encrypt timestamp
+
+	timestamp := tai64n.Now()
+	func() {
+		var key [chacha20poly1305.KeySize]byte
+		KDF2(
+			&handshake.chainKey,
+			&key,
+			handshake.chainKey[:],
+			handshake.precomputedStaticStatic[:],
+		)
+		aead, _ := chacha20poly1305.New(key[:])
+		aead.Seal(msg.Timestamp[:0], ZeroNonce[:], timestamp[:], handshake.hash[:])
+	}()
+
+	handshake.mixHash(msg.Timestamp[:])
+	handshake.state = HandshakeInitiationCreated
+	return &msg, nil
+}
+
+func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
+	var (
+		hash     [blake2s.Size]byte
+		chainKey [blake2s.Size]byte
+	)
+
+	if msg.Type != MessageInitiationType {
+		return nil
+	}
+
+	device.staticIdentity.RLock()
+	defer device.staticIdentity.RUnlock()
+
+	mixHash(&hash, &InitialHash, device.staticIdentity.publicKey[:])
+	mixHash(&hash, &hash, msg.Ephemeral[:])
+	mixKey(&chainKey, &InitialChainKey, msg.Ephemeral[:])
+
+	// decrypt static key
+
+	var err error
+	var peerPK NoisePublicKey
+	func() {
+		var key [chacha20poly1305.KeySize]byte
+		ss := device.staticIdentity.privateKey.sharedSecret(msg.Ephemeral)
+		KDF2(&chainKey, &key, chainKey[:], ss[:])
+		aead, _ := chacha20poly1305.New(key[:])
+		_, err = aead.Open(peerPK[:0], ZeroNonce[:], msg.Static[:], hash[:])
+	}()
+	if err != nil {
+		return nil
+	}
+	mixHash(&hash, &hash, msg.Static[:])
+
+	// lookup peer
+
+	peer := device.LookupPeer(peerPK)
+	if peer == nil {
+		return nil
+	}
+
+	handshake := &peer.handshake
+	if isZero(handshake.precomputedStaticStatic[:]) {
+		return nil
+	}
+
+	// verify identity
+
+	var timestamp tai64n.Timestamp
+	var key [chacha20poly1305.KeySize]byte
+
+	handshake.mutex.RLock()
+	KDF2(
+		&chainKey,
+		&key,
+		chainKey[:],
+		handshake.precomputedStaticStatic[:],
+	)
+	aead, _ := chacha20poly1305.New(key[:])
+	_, err = aead.Open(timestamp[:0], ZeroNonce[:], msg.Timestamp[:], hash[:])
+	if err != nil {
+		handshake.mutex.RUnlock()
+		return nil
+	}
+	mixHash(&hash, &hash, msg.Timestamp[:])
+
+	// protect against replay & flood
+
+	var ok bool
+	ok = timestamp.After(handshake.lastTimestamp)
+	ok = ok && time.Now().Sub(handshake.lastInitiationConsumption) > HandshakeInitationRate
+	handshake.mutex.RUnlock()
+	if !ok {
+		return nil
+	}
+
+	// update handshake state
+
+	handshake.mutex.Lock()
+
+	handshake.hash = hash
+	handshake.chainKey = chainKey
+	handshake.remoteIndex = msg.Sender
+	handshake.remoteEphemeral = msg.Ephemeral
+	handshake.lastTimestamp = timestamp
+	handshake.lastInitiationConsumption = time.Now()
+	handshake.state = HandshakeInitiationConsumed
+
+	handshake.mutex.Unlock()
+
+	setZero(hash[:])
+	setZero(chainKey[:])
+
+	return peer
+}
+
+func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error) {
+	handshake := &peer.handshake
+	handshake.mutex.Lock()
+	defer handshake.mutex.Unlock()
+
+	if handshake.state != HandshakeInitiationConsumed {
+		return nil, errors.New("handshake initiation must be consumed first")
+	}
+
+	// assign index
+
+	var err error
+	device.indexTable.Delete(handshake.localIndex)
+	handshake.localIndex, err = device.indexTable.NewIndexForHandshake(peer, handshake)
+	if err != nil {
+		return nil, err
+	}
+
+	var msg MessageResponse
+	msg.Type = MessageResponseType
+	msg.Sender = handshake.localIndex
+	msg.Receiver = handshake.remoteIndex
+
+	// create ephemeral key
+
+	handshake.localEphemeral, err = newPrivateKey()
+	if err != nil {
+		return nil, err
+	}
+	msg.Ephemeral = handshake.localEphemeral.publicKey()
+	handshake.mixHash(msg.Ephemeral[:])
+	handshake.mixKey(msg.Ephemeral[:])
+
+	func() {
+		ss := handshake.localEphemeral.sharedSecret(handshake.remoteEphemeral)
+		handshake.mixKey(ss[:])
+		ss = handshake.localEphemeral.sharedSecret(handshake.remoteStatic)
+		handshake.mixKey(ss[:])
+	}()
+
+	// add preshared key
+
+	var tau [blake2s.Size]byte
+	var key [chacha20poly1305.KeySize]byte
+
+	KDF3(
+		&handshake.chainKey,
+		&tau,
+		&key,
+		handshake.chainKey[:],
+		handshake.presharedKey[:],
+	)
+
+	handshake.mixHash(tau[:])
+
+	func() {
+		aead, _ := chacha20poly1305.New(key[:])
+		aead.Seal(msg.Empty[:0], ZeroNonce[:], nil, handshake.hash[:])
+		handshake.mixHash(msg.Empty[:])
+	}()
+
+	handshake.state = HandshakeResponseCreated
+
+	return &msg, nil
+}
+
+func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
+	if msg.Type != MessageResponseType {
+		return nil
+	}
+
+	// lookup handshake by receiver
+
+	lookup := device.indexTable.Lookup(msg.Receiver)
+	handshake := lookup.handshake
+	if handshake == nil {
+		return nil
+	}
+
+	var (
+		hash     [blake2s.Size]byte
+		chainKey [blake2s.Size]byte
+	)
+
+	ok := func() bool {
+
+		// lock handshake state
+
+		handshake.mutex.RLock()
+		defer handshake.mutex.RUnlock()
+
+		if handshake.state != HandshakeInitiationCreated {
+			return false
+		}
+
+		// lock private key for reading
+
+		device.staticIdentity.RLock()
+		defer device.staticIdentity.RUnlock()
+
+		// finish 3-way DH
+
+		mixHash(&hash, &handshake.hash, msg.Ephemeral[:])
+		mixKey(&chainKey, &handshake.chainKey, msg.Ephemeral[:])
+
+		func() {
+			ss := handshake.localEphemeral.sharedSecret(msg.Ephemeral)
+			mixKey(&chainKey, &chainKey, ss[:])
+			setZero(ss[:])
+		}()
+
+		func() {
+			ss := device.staticIdentity.privateKey.sharedSecret(msg.Ephemeral)
+			mixKey(&chainKey, &chainKey, ss[:])
+			setZero(ss[:])
+		}()
+
+		// add preshared key (psk)
+
+		var tau [blake2s.Size]byte
+		var key [chacha20poly1305.KeySize]byte
+		KDF3(
+			&chainKey,
+			&tau,
+			&key,
+			chainKey[:],
+			handshake.presharedKey[:],
+		)
+		mixHash(&hash, &hash, tau[:])
+
+		// authenticate transcript
+
+		aead, _ := chacha20poly1305.New(key[:])
+		_, err := aead.Open(nil, ZeroNonce[:], msg.Empty[:], hash[:])
+		if err != nil {
+			return false
+		}
+		mixHash(&hash, &hash, msg.Empty[:])
+		return true
+	}()
+
+	if !ok {
+		return nil
+	}
+
+	// update handshake state
+
+	handshake.mutex.Lock()
+
+	handshake.hash = hash
+	handshake.chainKey = chainKey
+	handshake.remoteIndex = msg.Sender
+	handshake.state = HandshakeResponseConsumed
+
+	handshake.mutex.Unlock()
+
+	setZero(hash[:])
+	setZero(chainKey[:])
+
+	return lookup.peer
+}
+
+/* Derives a new keypair from the current handshake state
+ *
+ */
+func (peer *Peer) BeginSymmetricSession() error {
+	device := peer.device
+	handshake := &peer.handshake
+	handshake.mutex.Lock()
+	defer handshake.mutex.Unlock()
+
+	// derive keys
+
+	var isInitiator bool
+	var sendKey [chacha20poly1305.KeySize]byte
+	var recvKey [chacha20poly1305.KeySize]byte
+
+	if handshake.state == HandshakeResponseConsumed {
+		KDF2(
+			&sendKey,
+			&recvKey,
+			handshake.chainKey[:],
+			nil,
+		)
+		isInitiator = true
+	} else if handshake.state == HandshakeResponseCreated {
+		KDF2(
+			&recvKey,
+			&sendKey,
+			handshake.chainKey[:],
+			nil,
+		)
+		isInitiator = false
+	} else {
+		return errors.New("invalid state for keypair derivation")
+	}
+
+	// zero handshake
+
+	setZero(handshake.chainKey[:])
+	setZero(handshake.hash[:]) // Doesn't necessarily need to be zeroed. Could be used for something interesting down the line.
+	setZero(handshake.localEphemeral[:])
+	peer.handshake.state = HandshakeZeroed
+
+	// create AEAD instances
+
+	keypair := new(Keypair)
+	keypair.send, _ = chacha20poly1305.New(sendKey[:])
+	keypair.receive, _ = chacha20poly1305.New(recvKey[:])
+
+	setZero(sendKey[:])
+	setZero(recvKey[:])
+
+	keypair.created = time.Now()
+	keypair.sendNonce = 0
+	keypair.replayFilter.Init()
+	keypair.isInitiator = isInitiator
+	keypair.localIndex = peer.handshake.localIndex
+	keypair.remoteIndex = peer.handshake.remoteIndex
+
+	// remap index
+
+	device.indexTable.SwapIndexForKeypair(handshake.localIndex, keypair)
+	handshake.localIndex = 0
+
+	// rotate key pairs
+
+	keypairs := &peer.keypairs
+	keypairs.Lock()
+	defer keypairs.Unlock()
+
+	previous := keypairs.previous
+	next := keypairs.next
+	current := keypairs.current
+
+	if isInitiator {
+		if next != nil {
+			keypairs.next = nil
+			keypairs.previous = next
+			device.DeleteKeypair(current)
+		} else {
+			keypairs.previous = current
+		}
+		device.DeleteKeypair(previous)
+		keypairs.current = keypair
+	} else {
+		keypairs.next = keypair
+		device.DeleteKeypair(next)
+		keypairs.previous = nil
+		device.DeleteKeypair(previous)
+	}
+
+	return nil
+}
+
+func (peer *Peer) ReceivedWithKeypair(receivedKeypair *Keypair) bool {
+	keypairs := &peer.keypairs
+	if keypairs.next != receivedKeypair {
+		return false
+	}
+	keypairs.Lock()
+	defer keypairs.Unlock()
+	if keypairs.next != receivedKeypair {
+		return false
+	}
+	old := keypairs.previous
+	keypairs.previous = keypairs.current
+	peer.device.DeleteKeypair(old)
+	keypairs.current = keypairs.next
+	keypairs.next = nil
+	return true
+}
diff --git a/device/noise-types.go b/device/noise-types.go
new file mode 100644
index 0000000..82b12c1
--- /dev/null
+++ b/device/noise-types.go
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"crypto/subtle"
+	"encoding/hex"
+	"errors"
+	"golang.org/x/crypto/chacha20poly1305"
+)
+
+const (
+	NoisePublicKeySize  = 32
+	NoisePrivateKeySize = 32
+)
+
+type (
+	NoisePublicKey    [NoisePublicKeySize]byte
+	NoisePrivateKey   [NoisePrivateKeySize]byte
+	NoiseSymmetricKey [chacha20poly1305.KeySize]byte
+	NoiseNonce        uint64 // padded to 12-bytes
+)
+
+func loadExactHex(dst []byte, src string) error {
+	slice, err := hex.DecodeString(src)
+	if err != nil {
+		return err
+	}
+	if len(slice) != len(dst) {
+		return errors.New("hex string does not fit the slice")
+	}
+	copy(dst, slice)
+	return nil
+}
+
+func (key NoisePrivateKey) IsZero() bool {
+	var zero NoisePrivateKey
+	return key.Equals(zero)
+}
+
+func (key NoisePrivateKey) Equals(tar NoisePrivateKey) bool {
+	return subtle.ConstantTimeCompare(key[:], tar[:]) == 1
+}
+
+func (key *NoisePrivateKey) FromHex(src string) (err error) {
+	err = loadExactHex(key[:], src)
+	key.clamp()
+	return
+}
+
+func (key NoisePrivateKey) ToHex() string {
+	return hex.EncodeToString(key[:])
+}
+
+func (key *NoisePublicKey) FromHex(src string) error {
+	return loadExactHex(key[:], src)
+}
+
+func (key NoisePublicKey) ToHex() string {
+	return hex.EncodeToString(key[:])
+}
+
+func (key NoisePublicKey) IsZero() bool {
+	var zero NoisePublicKey
+	return key.Equals(zero)
+}
+
+func (key NoisePublicKey) Equals(tar NoisePublicKey) bool {
+	return subtle.ConstantTimeCompare(key[:], tar[:]) == 1
+}
+
+func (key *NoiseSymmetricKey) FromHex(src string) error {
+	return loadExactHex(key[:], src)
+}
+
+func (key NoiseSymmetricKey) ToHex() string {
+	return hex.EncodeToString(key[:])
+}
diff --git a/device/noise_test.go b/device/noise_test.go
new file mode 100644
index 0000000..6ba3f2e
--- /dev/null
+++ b/device/noise_test.go
@@ -0,0 +1,144 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"bytes"
+	"encoding/binary"
+	"testing"
+)
+
+func TestCurveWrappers(t *testing.T) {
+	sk1, err := newPrivateKey()
+	assertNil(t, err)
+
+	sk2, err := newPrivateKey()
+	assertNil(t, err)
+
+	pk1 := sk1.publicKey()
+	pk2 := sk2.publicKey()
+
+	ss1 := sk1.sharedSecret(pk2)
+	ss2 := sk2.sharedSecret(pk1)
+
+	if ss1 != ss2 {
+		t.Fatal("Failed to compute shared secet")
+	}
+}
+
+func TestNoiseHandshake(t *testing.T) {
+	dev1 := randDevice(t)
+	dev2 := randDevice(t)
+
+	defer dev1.Close()
+	defer dev2.Close()
+
+	peer1, _ := dev2.NewPeer(dev1.staticIdentity.privateKey.publicKey())
+	peer2, _ := dev1.NewPeer(dev2.staticIdentity.privateKey.publicKey())
+
+	assertEqual(
+		t,
+		peer1.handshake.precomputedStaticStatic[:],
+		peer2.handshake.precomputedStaticStatic[:],
+	)
+
+	/* simulate handshake */
+
+	// initiation message
+
+	t.Log("exchange initiation message")
+
+	msg1, err := dev1.CreateMessageInitiation(peer2)
+	assertNil(t, err)
+
+	packet := make([]byte, 0, 256)
+	writer := bytes.NewBuffer(packet)
+	err = binary.Write(writer, binary.LittleEndian, msg1)
+	assertNil(t, err)
+	peer := dev2.ConsumeMessageInitiation(msg1)
+	if peer == nil {
+		t.Fatal("handshake failed at initiation message")
+	}
+
+	assertEqual(
+		t,
+		peer1.handshake.chainKey[:],
+		peer2.handshake.chainKey[:],
+	)
+
+	assertEqual(
+		t,
+		peer1.handshake.hash[:],
+		peer2.handshake.hash[:],
+	)
+
+	// response message
+
+	t.Log("exchange response message")
+
+	msg2, err := dev2.CreateMessageResponse(peer1)
+	assertNil(t, err)
+
+	peer = dev1.ConsumeMessageResponse(msg2)
+	if peer == nil {
+		t.Fatal("handshake failed at response message")
+	}
+
+	assertEqual(
+		t,
+		peer1.handshake.chainKey[:],
+		peer2.handshake.chainKey[:],
+	)
+
+	assertEqual(
+		t,
+		peer1.handshake.hash[:],
+		peer2.handshake.hash[:],
+	)
+
+	// key pairs
+
+	t.Log("deriving keys")
+
+	err = peer1.BeginSymmetricSession()
+	if err != nil {
+		t.Fatal("failed to derive keypair for peer 1", err)
+	}
+
+	err = peer2.BeginSymmetricSession()
+	if err != nil {
+		t.Fatal("failed to derive keypair for peer 2", err)
+	}
+
+	key1 := peer1.keypairs.next
+	key2 := peer2.keypairs.current
+
+	// encrypting / decryption test
+
+	t.Log("test key pairs")
+
+	func() {
+		testMsg := []byte("wireguard test message 1")
+		var err error
+		var out []byte
+		var nonce [12]byte
+		out = key1.send.Seal(out, nonce[:], testMsg, nil)
+		out, err = key2.receive.Open(out[:0], nonce[:], out, nil)
+		assertNil(t, err)
+		assertEqual(t, out, testMsg)
+	}()
+
+	func() {
+		testMsg := []byte("wireguard test message 2")
+		var err error
+		var out []byte
+		var nonce [12]byte
+		out = key2.send.Seal(out, nonce[:], testMsg, nil)
+		out, err = key1.receive.Open(out[:0], nonce[:], out, nil)
+		assertNil(t, err)
+		assertEqual(t, out, testMsg)
+	}()
+}
diff --git a/device/peer.go b/device/peer.go
new file mode 100644
index 0000000..af3ef9d
--- /dev/null
+++ b/device/peer.go
@@ -0,0 +1,270 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+)
+
+const (
+	PeerRoutineNumber = 3
+)
+
+type Peer struct {
+	isRunning                   AtomicBool
+	sync.RWMutex                // Mostly protects endpoint, but is generally taken whenever we modify peer
+	keypairs                    Keypairs
+	handshake                   Handshake
+	device                      *Device
+	endpoint                    Endpoint
+	persistentKeepaliveInterval uint16
+
+	// This must be 64-bit aligned, so make sure the above members come out to even alignment and pad accordingly
+	stats struct {
+		txBytes           uint64 // bytes send to peer (endpoint)
+		rxBytes           uint64 // bytes received from peer
+		lastHandshakeNano int64  // nano seconds since epoch
+	}
+
+	timers struct {
+		retransmitHandshake     *Timer
+		sendKeepalive           *Timer
+		newHandshake            *Timer
+		zeroKeyMaterial         *Timer
+		persistentKeepalive     *Timer
+		handshakeAttempts       uint32
+		needAnotherKeepalive    AtomicBool
+		sentLastMinuteHandshake AtomicBool
+	}
+
+	signals struct {
+		newKeypairArrived chan struct{}
+		flushNonceQueue   chan struct{}
+	}
+
+	queue struct {
+		nonce                           chan *QueueOutboundElement // nonce / pre-handshake queue
+		outbound                        chan *QueueOutboundElement // sequential ordering of work
+		inbound                         chan *QueueInboundElement  // sequential ordering of work
+		packetInNonceQueueIsAwaitingKey AtomicBool
+	}
+
+	routines struct {
+		sync.Mutex                // held when stopping / starting routines
+		starting   sync.WaitGroup // routines pending start
+		stopping   sync.WaitGroup // routines pending stop
+		stop       chan struct{}  // size 0, stop all go routines in peer
+	}
+
+	cookieGenerator CookieGenerator
+}
+
+func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
+
+	if device.isClosed.Get() {
+		return nil, errors.New("device closed")
+	}
+
+	// lock resources
+
+	device.staticIdentity.RLock()
+	defer device.staticIdentity.RUnlock()
+
+	device.peers.Lock()
+	defer device.peers.Unlock()
+
+	// check if over limit
+
+	if len(device.peers.keyMap) >= MaxPeers {
+		return nil, errors.New("too many peers")
+	}
+
+	// create peer
+
+	peer := new(Peer)
+	peer.Lock()
+	defer peer.Unlock()
+
+	peer.cookieGenerator.Init(pk)
+	peer.device = device
+	peer.isRunning.Set(false)
+
+	// map public key
+
+	_, ok := device.peers.keyMap[pk]
+	if ok {
+		return nil, errors.New("adding existing peer")
+	}
+	device.peers.keyMap[pk] = peer
+
+	// pre-compute DH
+
+	handshake := &peer.handshake
+	handshake.mutex.Lock()
+	handshake.remoteStatic = pk
+	handshake.precomputedStaticStatic = device.staticIdentity.privateKey.sharedSecret(pk)
+	handshake.mutex.Unlock()
+
+	// reset endpoint
+
+	peer.endpoint = nil
+
+	// start peer
+
+	if peer.device.isUp.Get() {
+		peer.Start()
+	}
+
+	return peer, nil
+}
+
+func (peer *Peer) SendBuffer(buffer []byte) error {
+	peer.device.net.RLock()
+	defer peer.device.net.RUnlock()
+
+	if peer.device.net.bind == nil {
+		return errors.New("no bind")
+	}
+
+	peer.RLock()
+	defer peer.RUnlock()
+
+	if peer.endpoint == nil {
+		return errors.New("no known endpoint for peer")
+	}
+
+	return peer.device.net.bind.Send(buffer, peer.endpoint)
+}
+
+func (peer *Peer) String() string {
+	base64Key := base64.StdEncoding.EncodeToString(peer.handshake.remoteStatic[:])
+	abbreviatedKey := "invalid"
+	if len(base64Key) == 44 {
+		abbreviatedKey = base64Key[0:4] + "…" + base64Key[39:43]
+	}
+	return fmt.Sprintf("peer(%s)", abbreviatedKey)
+}
+
+func (peer *Peer) Start() {
+
+	// should never start a peer on a closed device
+
+	if peer.device.isClosed.Get() {
+		return
+	}
+
+	// prevent simultaneous start/stop operations
+
+	peer.routines.Lock()
+	defer peer.routines.Unlock()
+
+	if peer.isRunning.Get() {
+		return
+	}
+
+	device := peer.device
+	device.log.Debug.Println(peer, "- Starting...")
+
+	// reset routine state
+
+	peer.routines.starting.Wait()
+	peer.routines.stopping.Wait()
+	peer.routines.stop = make(chan struct{})
+	peer.routines.starting.Add(PeerRoutineNumber)
+	peer.routines.stopping.Add(PeerRoutineNumber)
+
+	// prepare queues
+
+	peer.queue.nonce = make(chan *QueueOutboundElement, QueueOutboundSize)
+	peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
+	peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
+
+	peer.timersInit()
+	peer.handshake.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
+	peer.signals.newKeypairArrived = make(chan struct{}, 1)
+	peer.signals.flushNonceQueue = make(chan struct{}, 1)
+
+	// wait for routines to start
+
+	go peer.RoutineNonce()
+	go peer.RoutineSequentialSender()
+	go peer.RoutineSequentialReceiver()
+
+	peer.routines.starting.Wait()
+	peer.isRunning.Set(true)
+}
+
+func (peer *Peer) ZeroAndFlushAll() {
+	device := peer.device
+
+	// clear key pairs
+
+	keypairs := &peer.keypairs
+	keypairs.Lock()
+	device.DeleteKeypair(keypairs.previous)
+	device.DeleteKeypair(keypairs.current)
+	device.DeleteKeypair(keypairs.next)
+	keypairs.previous = nil
+	keypairs.current = nil
+	keypairs.next = nil
+	keypairs.Unlock()
+
+	// clear handshake state
+
+	handshake := &peer.handshake
+	handshake.mutex.Lock()
+	device.indexTable.Delete(handshake.localIndex)
+	handshake.Clear()
+	handshake.mutex.Unlock()
+
+	peer.FlushNonceQueue()
+}
+
+func (peer *Peer) Stop() {
+
+	// prevent simultaneous start/stop operations
+
+	if !peer.isRunning.Swap(false) {
+		return
+	}
+
+	peer.routines.starting.Wait()
+
+	peer.routines.Lock()
+	defer peer.routines.Unlock()
+
+	peer.device.log.Debug.Println(peer, "- Stopping...")
+
+	peer.timersStop()
+
+	// stop & wait for ongoing peer routines
+
+	close(peer.routines.stop)
+	peer.routines.stopping.Wait()
+
+	// close queues
+
+	close(peer.queue.nonce)
+	close(peer.queue.outbound)
+	close(peer.queue.inbound)
+
+	peer.ZeroAndFlushAll()
+}
+
+var roamingDisabled bool
+
+func (peer *Peer) SetEndpointFromPacket(endpoint Endpoint) {
+	if roamingDisabled {
+		return
+	}
+	peer.Lock()
+	peer.endpoint = endpoint
+	peer.Unlock()
+}
diff --git a/device/pools.go b/device/pools.go
new file mode 100644
index 0000000..98f4ef1
--- /dev/null
+++ b/device/pools.go
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import "sync"
+
+func (device *Device) PopulatePools() {
+	if PreallocatedBuffersPerPool == 0 {
+		device.pool.messageBufferPool = &sync.Pool{
+			New: func() interface{} {
+				return new([MaxMessageSize]byte)
+			},
+		}
+		device.pool.inboundElementPool = &sync.Pool{
+			New: func() interface{} {
+				return new(QueueInboundElement)
+			},
+		}
+		device.pool.outboundElementPool = &sync.Pool{
+			New: func() interface{} {
+				return new(QueueOutboundElement)
+			},
+		}
+	} else {
+		device.pool.messageBufferReuseChan = make(chan *[MaxMessageSize]byte, PreallocatedBuffersPerPool)
+		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
+			device.pool.messageBufferReuseChan <- new([MaxMessageSize]byte)
+		}
+		device.pool.inboundElementReuseChan = make(chan *QueueInboundElement, PreallocatedBuffersPerPool)
+		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
+			device.pool.inboundElementReuseChan <- new(QueueInboundElement)
+		}
+		device.pool.outboundElementReuseChan = make(chan *QueueOutboundElement, PreallocatedBuffersPerPool)
+		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
+			device.pool.outboundElementReuseChan <- new(QueueOutboundElement)
+		}
+	}
+}
+
+func (device *Device) GetMessageBuffer() *[MaxMessageSize]byte {
+	if PreallocatedBuffersPerPool == 0 {
+		return device.pool.messageBufferPool.Get().(*[MaxMessageSize]byte)
+	} else {
+		return <-device.pool.messageBufferReuseChan
+	}
+}
+
+func (device *Device) PutMessageBuffer(msg *[MaxMessageSize]byte) {
+	if PreallocatedBuffersPerPool == 0 {
+		device.pool.messageBufferPool.Put(msg)
+	} else {
+		device.pool.messageBufferReuseChan <- msg
+	}
+}
+
+func (device *Device) GetInboundElement() *QueueInboundElement {
+	if PreallocatedBuffersPerPool == 0 {
+		return device.pool.inboundElementPool.Get().(*QueueInboundElement)
+	} else {
+		return <-device.pool.inboundElementReuseChan
+	}
+}
+
+func (device *Device) PutInboundElement(msg *QueueInboundElement) {
+	if PreallocatedBuffersPerPool == 0 {
+		device.pool.inboundElementPool.Put(msg)
+	} else {
+		device.pool.inboundElementReuseChan <- msg
+	}
+}
+
+func (device *Device) GetOutboundElement() *QueueOutboundElement {
+	if PreallocatedBuffersPerPool == 0 {
+		return device.pool.outboundElementPool.Get().(*QueueOutboundElement)
+	} else {
+		return <-device.pool.outboundElementReuseChan
+	}
+}
+
+func (device *Device) PutOutboundElement(msg *QueueOutboundElement) {
+	if PreallocatedBuffersPerPool == 0 {
+		device.pool.outboundElementPool.Put(msg)
+	} else {
+		device.pool.outboundElementReuseChan <- msg
+	}
+}
diff --git a/device/queueconstants.go b/device/queueconstants.go
new file mode 100644
index 0000000..3e94b7f
--- /dev/null
+++ b/device/queueconstants.go
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+/* Implementation specific constants */
+
+const (
+	QueueOutboundSize          = 1024
+	QueueInboundSize           = 1024
+	QueueHandshakeSize         = 1024
+	MaxSegmentSize             = (1 << 16) - 1 // largest possible UDP datagram
+	PreallocatedBuffersPerPool = 0             // Disable and allow for infinite memory growth
+)
diff --git a/device/receive.go b/device/receive.go
new file mode 100644
index 0000000..5c837c1
--- /dev/null
+++ b/device/receive.go
@@ -0,0 +1,641 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"bytes"
+	"encoding/binary"
+	"golang.org/x/crypto/chacha20poly1305"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+	"net"
+	"strconv"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type QueueHandshakeElement struct {
+	msgType  uint32
+	packet   []byte
+	endpoint Endpoint
+	buffer   *[MaxMessageSize]byte
+}
+
+type QueueInboundElement struct {
+	dropped int32
+	sync.Mutex
+	buffer   *[MaxMessageSize]byte
+	packet   []byte
+	counter  uint64
+	keypair  *Keypair
+	endpoint Endpoint
+}
+
+func (elem *QueueInboundElement) Drop() {
+	atomic.StoreInt32(&elem.dropped, AtomicTrue)
+}
+
+func (elem *QueueInboundElement) IsDropped() bool {
+	return atomic.LoadInt32(&elem.dropped) == AtomicTrue
+}
+
+func (device *Device) addToInboundAndDecryptionQueues(inboundQueue chan *QueueInboundElement, decryptionQueue chan *QueueInboundElement, element *QueueInboundElement) bool {
+	select {
+	case inboundQueue <- element:
+		select {
+		case decryptionQueue <- element:
+			return true
+		default:
+			element.Drop()
+			element.Unlock()
+			return false
+		}
+	default:
+		device.PutInboundElement(element)
+		return false
+	}
+}
+
+func (device *Device) addToHandshakeQueue(queue chan QueueHandshakeElement, element QueueHandshakeElement) bool {
+	select {
+	case queue <- element:
+		return true
+	default:
+		return false
+	}
+}
+
+/* Called when a new authenticated message has been received
+ *
+ * NOTE: Not thread safe, but called by sequential receiver!
+ */
+func (peer *Peer) keepKeyFreshReceiving() {
+	if peer.timers.sentLastMinuteHandshake.Get() {
+		return
+	}
+	keypair := peer.keypairs.Current()
+	if keypair != nil && keypair.isInitiator && time.Now().Sub(keypair.created) > (RejectAfterTime-KeepaliveTimeout-RekeyTimeout) {
+		peer.timers.sentLastMinuteHandshake.Set(true)
+		peer.SendHandshakeInitiation(false)
+	}
+}
+
+/* Receives incoming datagrams for the device
+ *
+ * Every time the bind is updated a new routine is started for
+ * IPv4 and IPv6 (separately)
+ */
+func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
+
+	logDebug := device.log.Debug
+	defer func() {
+		logDebug.Println("Routine: receive incoming IPv" + strconv.Itoa(IP) + " - stopped")
+		device.net.stopping.Done()
+	}()
+
+	logDebug.Println("Routine: receive incoming IPv" + strconv.Itoa(IP) + " - started")
+	device.net.starting.Done()
+
+	// receive datagrams until conn is closed
+
+	buffer := device.GetMessageBuffer()
+
+	var (
+		err      error
+		size     int
+		endpoint Endpoint
+	)
+
+	for {
+
+		// read next datagram
+
+		switch IP {
+		case ipv4.Version:
+			size, endpoint, err = bind.ReceiveIPv4(buffer[:])
+		case ipv6.Version:
+			size, endpoint, err = bind.ReceiveIPv6(buffer[:])
+		default:
+			panic("invalid IP version")
+		}
+
+		if err != nil {
+			device.PutMessageBuffer(buffer)
+			return
+		}
+
+		if size < MinMessageSize {
+			continue
+		}
+
+		// check size of packet
+
+		packet := buffer[:size]
+		msgType := binary.LittleEndian.Uint32(packet[:4])
+
+		var okay bool
+
+		switch msgType {
+
+		// check if transport
+
+		case MessageTransportType:
+
+			// check size
+
+			if len(packet) < MessageTransportSize {
+				continue
+			}
+
+			// lookup key pair
+
+			receiver := binary.LittleEndian.Uint32(
+				packet[MessageTransportOffsetReceiver:MessageTransportOffsetCounter],
+			)
+			value := device.indexTable.Lookup(receiver)
+			keypair := value.keypair
+			if keypair == nil {
+				continue
+			}
+
+			// check keypair expiry
+
+			if keypair.created.Add(RejectAfterTime).Before(time.Now()) {
+				continue
+			}
+
+			// create work element
+			peer := value.peer
+			elem := device.GetInboundElement()
+			elem.packet = packet
+			elem.buffer = buffer
+			elem.keypair = keypair
+			elem.dropped = AtomicFalse
+			elem.endpoint = endpoint
+			elem.counter = 0
+			elem.Mutex = sync.Mutex{}
+			elem.Lock()
+
+			// add to decryption queues
+
+			if peer.isRunning.Get() {
+				if device.addToInboundAndDecryptionQueues(peer.queue.inbound, device.queue.decryption, elem) {
+					buffer = device.GetMessageBuffer()
+				}
+			}
+
+			continue
+
+		// otherwise it is a fixed size & handshake related packet
+
+		case MessageInitiationType:
+			okay = len(packet) == MessageInitiationSize
+
+		case MessageResponseType:
+			okay = len(packet) == MessageResponseSize
+
+		case MessageCookieReplyType:
+			okay = len(packet) == MessageCookieReplySize
+
+		default:
+			logDebug.Println("Received message with unknown type")
+		}
+
+		if okay {
+			if (device.addToHandshakeQueue(
+				device.queue.handshake,
+				QueueHandshakeElement{
+					msgType:  msgType,
+					buffer:   buffer,
+					packet:   packet,
+					endpoint: endpoint,
+				},
+			)) {
+				buffer = device.GetMessageBuffer()
+			}
+		}
+	}
+}
+
+func (device *Device) RoutineDecryption() {
+
+	var nonce [chacha20poly1305.NonceSize]byte
+
+	logDebug := device.log.Debug
+	defer func() {
+		logDebug.Println("Routine: decryption worker - stopped")
+		device.state.stopping.Done()
+	}()
+	logDebug.Println("Routine: decryption worker - started")
+	device.state.starting.Done()
+
+	for {
+		select {
+		case <-device.signals.stop:
+			return
+
+		case elem, ok := <-device.queue.decryption:
+
+			if !ok {
+				return
+			}
+
+			// check if dropped
+
+			if elem.IsDropped() {
+				continue
+			}
+
+			// split message into fields
+
+			counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent]
+			content := elem.packet[MessageTransportOffsetContent:]
+
+			// expand nonce
+
+			nonce[0x4] = counter[0x0]
+			nonce[0x5] = counter[0x1]
+			nonce[0x6] = counter[0x2]
+			nonce[0x7] = counter[0x3]
+
+			nonce[0x8] = counter[0x4]
+			nonce[0x9] = counter[0x5]
+			nonce[0xa] = counter[0x6]
+			nonce[0xb] = counter[0x7]
+
+			// decrypt and release to consumer
+
+			var err error
+			elem.counter = binary.LittleEndian.Uint64(counter)
+			elem.packet, err = elem.keypair.receive.Open(
+				content[:0],
+				nonce[:],
+				content,
+				nil,
+			)
+			if err != nil {
+				elem.Drop()
+				device.PutMessageBuffer(elem.buffer)
+			}
+			elem.Unlock()
+		}
+	}
+}
+
+/* Handles incoming packets related to handshake
+ */
+func (device *Device) RoutineHandshake() {
+
+	logInfo := device.log.Info
+	logError := device.log.Error
+	logDebug := device.log.Debug
+
+	var elem QueueHandshakeElement
+	var ok bool
+
+	defer func() {
+		logDebug.Println("Routine: handshake worker - stopped")
+		device.state.stopping.Done()
+		if elem.buffer != nil {
+			device.PutMessageBuffer(elem.buffer)
+		}
+	}()
+
+	logDebug.Println("Routine: handshake worker - started")
+	device.state.starting.Done()
+
+	for {
+		if elem.buffer != nil {
+			device.PutMessageBuffer(elem.buffer)
+			elem.buffer = nil
+		}
+
+		select {
+		case elem, ok = <-device.queue.handshake:
+		case <-device.signals.stop:
+			return
+		}
+
+		if !ok {
+			return
+		}
+
+		// handle cookie fields and ratelimiting
+
+		switch elem.msgType {
+
+		case MessageCookieReplyType:
+
+			// unmarshal packet
+
+			var reply MessageCookieReply
+			reader := bytes.NewReader(elem.packet)
+			err := binary.Read(reader, binary.LittleEndian, &reply)
+			if err != nil {
+				logDebug.Println("Failed to decode cookie reply")
+				return
+			}
+
+			// lookup peer from index
+
+			entry := device.indexTable.Lookup(reply.Receiver)
+
+			if entry.peer == nil {
+				continue
+			}
+
+			// consume reply
+
+			if peer := entry.peer; peer.isRunning.Get() {
+				logDebug.Println("Receiving cookie response from ", elem.endpoint.DstToString())
+				if !peer.cookieGenerator.ConsumeReply(&reply) {
+					logDebug.Println("Could not decrypt invalid cookie response")
+				}
+			}
+
+			continue
+
+		case MessageInitiationType, MessageResponseType:
+
+			// check mac fields and maybe ratelimit
+
+			if !device.cookieChecker.CheckMAC1(elem.packet) {
+				logDebug.Println("Received packet with invalid mac1")
+				continue
+			}
+
+			// endpoints destination address is the source of the datagram
+
+			if device.IsUnderLoad() {
+
+				// verify MAC2 field
+
+				if !device.cookieChecker.CheckMAC2(elem.packet, elem.endpoint.DstToBytes()) {
+					device.SendHandshakeCookie(&elem)
+					continue
+				}
+
+				// check ratelimiter
+
+				if !device.rate.limiter.Allow(elem.endpoint.DstIP()) {
+					continue
+				}
+			}
+
+		default:
+			logError.Println("Invalid packet ended up in the handshake queue")
+			continue
+		}
+
+		// handle handshake initiation/response content
+
+		switch elem.msgType {
+		case MessageInitiationType:
+
+			// unmarshal
+
+			var msg MessageInitiation
+			reader := bytes.NewReader(elem.packet)
+			err := binary.Read(reader, binary.LittleEndian, &msg)
+			if err != nil {
+				logError.Println("Failed to decode initiation message")
+				continue
+			}
+
+			// consume initiation
+
+			peer := device.ConsumeMessageInitiation(&msg)
+			if peer == nil {
+				logInfo.Println(
+					"Received invalid initiation message from",
+					elem.endpoint.DstToString(),
+				)
+				continue
+			}
+
+			// update timers
+
+			peer.timersAnyAuthenticatedPacketTraversal()
+			peer.timersAnyAuthenticatedPacketReceived()
+
+			// update endpoint
+			peer.SetEndpointFromPacket(elem.endpoint)
+
+			logDebug.Println(peer, "- Received handshake initiation")
+
+			peer.SendHandshakeResponse()
+
+		case MessageResponseType:
+
+			// unmarshal
+
+			var msg MessageResponse
+			reader := bytes.NewReader(elem.packet)
+			err := binary.Read(reader, binary.LittleEndian, &msg)
+			if err != nil {
+				logError.Println("Failed to decode response message")
+				continue
+			}
+
+			// consume response
+
+			peer := device.ConsumeMessageResponse(&msg)
+			if peer == nil {
+				logInfo.Println(
+					"Received invalid response message from",
+					elem.endpoint.DstToString(),
+				)
+				continue
+			}
+
+			// update endpoint
+			peer.SetEndpointFromPacket(elem.endpoint)
+
+			logDebug.Println(peer, "- Received handshake response")
+
+			// update timers
+
+			peer.timersAnyAuthenticatedPacketTraversal()
+			peer.timersAnyAuthenticatedPacketReceived()
+
+			// derive keypair
+
+			err = peer.BeginSymmetricSession()
+
+			if err != nil {
+				logError.Println(peer, "- Failed to derive keypair:", err)
+				continue
+			}
+
+			peer.timersSessionDerived()
+			peer.timersHandshakeComplete()
+			peer.SendKeepalive()
+			select {
+			case peer.signals.newKeypairArrived <- struct{}{}:
+			default:
+			}
+		}
+	}
+}
+
+func (peer *Peer) RoutineSequentialReceiver() {
+
+	device := peer.device
+	logInfo := device.log.Info
+	logError := device.log.Error
+	logDebug := device.log.Debug
+
+	var elem *QueueInboundElement
+	var ok bool
+
+	defer func() {
+		logDebug.Println(peer, "- Routine: sequential receiver - stopped")
+		peer.routines.stopping.Done()
+		if elem != nil {
+			if !elem.IsDropped() {
+				device.PutMessageBuffer(elem.buffer)
+			}
+			device.PutInboundElement(elem)
+		}
+	}()
+
+	logDebug.Println(peer, "- Routine: sequential receiver - started")
+
+	peer.routines.starting.Done()
+
+	for {
+		if elem != nil {
+			if !elem.IsDropped() {
+				device.PutMessageBuffer(elem.buffer)
+			}
+			device.PutInboundElement(elem)
+			elem = nil
+		}
+
+		select {
+
+		case <-peer.routines.stop:
+			return
+
+		case elem, ok = <-peer.queue.inbound:
+
+			if !ok {
+				return
+			}
+
+			// wait for decryption
+
+			elem.Lock()
+
+			if elem.IsDropped() {
+				continue
+			}
+
+			// check for replay
+
+			if !elem.keypair.replayFilter.ValidateCounter(elem.counter, RejectAfterMessages) {
+				continue
+			}
+
+			// update endpoint
+			peer.SetEndpointFromPacket(elem.endpoint)
+
+			// check if using new keypair
+			if peer.ReceivedWithKeypair(elem.keypair) {
+				peer.timersHandshakeComplete()
+				select {
+				case peer.signals.newKeypairArrived <- struct{}{}:
+				default:
+				}
+			}
+
+			peer.keepKeyFreshReceiving()
+			peer.timersAnyAuthenticatedPacketTraversal()
+			peer.timersAnyAuthenticatedPacketReceived()
+
+			// check for keepalive
+
+			if len(elem.packet) == 0 {
+				logDebug.Println(peer, "- Receiving keepalive packet")
+				continue
+			}
+			peer.timersDataReceived()
+
+			// verify source and strip padding
+
+			switch elem.packet[0] >> 4 {
+			case ipv4.Version:
+
+				// strip padding
+
+				if len(elem.packet) < ipv4.HeaderLen {
+					continue
+				}
+
+				field := elem.packet[IPv4offsetTotalLength : IPv4offsetTotalLength+2]
+				length := binary.BigEndian.Uint16(field)
+				if int(length) > len(elem.packet) || int(length) < ipv4.HeaderLen {
+					continue
+				}
+
+				elem.packet = elem.packet[:length]
+
+				// verify IPv4 source
+
+				src := elem.packet[IPv4offsetSrc : IPv4offsetSrc+net.IPv4len]
+				if device.allowedips.LookupIPv4(src) != peer {
+					logInfo.Println(
+						"IPv4 packet with disallowed source address from",
+						peer,
+					)
+					continue
+				}
+
+			case ipv6.Version:
+
+				// strip padding
+
+				if len(elem.packet) < ipv6.HeaderLen {
+					continue
+				}
+
+				field := elem.packet[IPv6offsetPayloadLength : IPv6offsetPayloadLength+2]
+				length := binary.BigEndian.Uint16(field)
+				length += ipv6.HeaderLen
+				if int(length) > len(elem.packet) {
+					continue
+				}
+
+				elem.packet = elem.packet[:length]
+
+				// verify IPv6 source
+
+				src := elem.packet[IPv6offsetSrc : IPv6offsetSrc+net.IPv6len]
+				if device.allowedips.LookupIPv6(src) != peer {
+					logInfo.Println(
+						peer,
+						"sent packet with disallowed IPv6 source",
+					)
+					continue
+				}
+
+			default:
+				logInfo.Println("Packet with invalid IP version from", peer)
+				continue
+			}
+
+			// write to tun device
+
+			offset := MessageTransportOffsetContent
+			atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
+			_, err := device.tun.device.Write(elem.buffer[:offset+len(elem.packet)], offset)
+			if err != nil {
+				logError.Println("Failed to write packet to TUN device:", err)
+			}
+		}
+	}
+}
diff --git a/device/send.go b/device/send.go
new file mode 100644
index 0000000..b4e23c7
--- /dev/null
+++ b/device/send.go
@@ -0,0 +1,618 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"bytes"
+	"encoding/binary"
+	"golang.org/x/crypto/chacha20poly1305"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+	"net"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+/* Outbound flow
+ *
+ * 1. TUN queue
+ * 2. Routing (sequential)
+ * 3. Nonce assignment (sequential)
+ * 4. Encryption (parallel)
+ * 5. Transmission (sequential)
+ *
+ * The functions in this file occur (roughly) in the order in
+ * which the packets are processed.
+ *
+ * Locking, Producers and Consumers
+ *
+ * The order of packets (per peer) must be maintained,
+ * but encryption of packets happen out-of-order:
+ *
+ * The sequential consumers will attempt to take the lock,
+ * workers release lock when they have completed work (encryption) on the packet.
+ *
+ * If the element is inserted into the "encryption queue",
+ * the content is preceded by enough "junk" to contain the transport header
+ * (to allow the construction of transport messages in-place)
+ */
+
+type QueueOutboundElement struct {
+	dropped int32
+	sync.Mutex
+	buffer  *[MaxMessageSize]byte // slice holding the packet data
+	packet  []byte                // slice of "buffer" (always!)
+	nonce   uint64                // nonce for encryption
+	keypair *Keypair              // keypair for encryption
+	peer    *Peer                 // related peer
+}
+
+func (device *Device) NewOutboundElement() *QueueOutboundElement {
+	elem := device.GetOutboundElement()
+	elem.dropped = AtomicFalse
+	elem.buffer = device.GetMessageBuffer()
+	elem.Mutex = sync.Mutex{}
+	elem.nonce = 0
+	elem.keypair = nil
+	elem.peer = nil
+	return elem
+}
+
+func (elem *QueueOutboundElement) Drop() {
+	atomic.StoreInt32(&elem.dropped, AtomicTrue)
+}
+
+func (elem *QueueOutboundElement) IsDropped() bool {
+	return atomic.LoadInt32(&elem.dropped) == AtomicTrue
+}
+
+func addToNonceQueue(queue chan *QueueOutboundElement, element *QueueOutboundElement, device *Device) {
+	for {
+		select {
+		case queue <- element:
+			return
+		default:
+			select {
+			case old := <-queue:
+				device.PutMessageBuffer(old.buffer)
+				device.PutOutboundElement(old)
+			default:
+			}
+		}
+	}
+}
+
+func addToOutboundAndEncryptionQueues(outboundQueue chan *QueueOutboundElement, encryptionQueue chan *QueueOutboundElement, element *QueueOutboundElement) {
+	select {
+	case outboundQueue <- element:
+		select {
+		case encryptionQueue <- element:
+			return
+		default:
+			element.Drop()
+			element.peer.device.PutMessageBuffer(element.buffer)
+			element.Unlock()
+		}
+	default:
+		element.peer.device.PutMessageBuffer(element.buffer)
+		element.peer.device.PutOutboundElement(element)
+	}
+}
+
+/* Queues a keepalive if no packets are queued for peer
+ */
+func (peer *Peer) SendKeepalive() bool {
+	if len(peer.queue.nonce) != 0 || peer.queue.packetInNonceQueueIsAwaitingKey.Get() || !peer.isRunning.Get() {
+		return false
+	}
+	elem := peer.device.NewOutboundElement()
+	elem.packet = nil
+	select {
+	case peer.queue.nonce <- elem:
+		peer.device.log.Debug.Println(peer, "- Sending keepalive packet")
+		return true
+	default:
+		peer.device.PutMessageBuffer(elem.buffer)
+		peer.device.PutOutboundElement(elem)
+		return false
+	}
+}
+
+func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
+	if !isRetry {
+		atomic.StoreUint32(&peer.timers.handshakeAttempts, 0)
+	}
+
+	peer.handshake.mutex.RLock()
+	if time.Now().Sub(peer.handshake.lastSentHandshake) < RekeyTimeout {
+		peer.handshake.mutex.RUnlock()
+		return nil
+	}
+	peer.handshake.mutex.RUnlock()
+
+	peer.handshake.mutex.Lock()
+	if time.Now().Sub(peer.handshake.lastSentHandshake) < RekeyTimeout {
+		peer.handshake.mutex.Unlock()
+		return nil
+	}
+	peer.handshake.lastSentHandshake = time.Now()
+	peer.handshake.mutex.Unlock()
+
+	peer.device.log.Debug.Println(peer, "- Sending handshake initiation")
+
+	msg, err := peer.device.CreateMessageInitiation(peer)
+	if err != nil {
+		peer.device.log.Error.Println(peer, "- Failed to create initiation message:", err)
+		return err
+	}
+
+	var buff [MessageInitiationSize]byte
+	writer := bytes.NewBuffer(buff[:0])
+	binary.Write(writer, binary.LittleEndian, msg)
+	packet := writer.Bytes()
+	peer.cookieGenerator.AddMacs(packet)
+
+	peer.timersAnyAuthenticatedPacketTraversal()
+	peer.timersAnyAuthenticatedPacketSent()
+
+	err = peer.SendBuffer(packet)
+	if err != nil {
+		peer.device.log.Error.Println(peer, "- Failed to send handshake initiation", err)
+	}
+	peer.timersHandshakeInitiated()
+
+	return err
+}
+
+func (peer *Peer) SendHandshakeResponse() error {
+	peer.handshake.mutex.Lock()
+	peer.handshake.lastSentHandshake = time.Now()
+	peer.handshake.mutex.Unlock()
+
+	peer.device.log.Debug.Println(peer, "- Sending handshake response")
+
+	response, err := peer.device.CreateMessageResponse(peer)
+	if err != nil {
+		peer.device.log.Error.Println(peer, "- Failed to create response message:", err)
+		return err
+	}
+
+	var buff [MessageResponseSize]byte
+	writer := bytes.NewBuffer(buff[:0])
+	binary.Write(writer, binary.LittleEndian, response)
+	packet := writer.Bytes()
+	peer.cookieGenerator.AddMacs(packet)
+
+	err = peer.BeginSymmetricSession()
+	if err != nil {
+		peer.device.log.Error.Println(peer, "- Failed to derive keypair:", err)
+		return err
+	}
+
+	peer.timersSessionDerived()
+	peer.timersAnyAuthenticatedPacketTraversal()
+	peer.timersAnyAuthenticatedPacketSent()
+
+	err = peer.SendBuffer(packet)
+	if err != nil {
+		peer.device.log.Error.Println(peer, "- Failed to send handshake response", err)
+	}
+	return err
+}
+
+func (device *Device) SendHandshakeCookie(initiatingElem *QueueHandshakeElement) error {
+
+	device.log.Debug.Println("Sending cookie response for denied handshake message for", initiatingElem.endpoint.DstToString())
+
+	sender := binary.LittleEndian.Uint32(initiatingElem.packet[4:8])
+	reply, err := device.cookieChecker.CreateReply(initiatingElem.packet, sender, initiatingElem.endpoint.DstToBytes())
+	if err != nil {
+		device.log.Error.Println("Failed to create cookie reply:", err)
+		return err
+	}
+
+	var buff [MessageCookieReplySize]byte
+	writer := bytes.NewBuffer(buff[:0])
+	binary.Write(writer, binary.LittleEndian, reply)
+	device.net.bind.Send(writer.Bytes(), initiatingElem.endpoint)
+	if err != nil {
+		device.log.Error.Println("Failed to send cookie reply:", err)
+	}
+	return err
+}
+
+func (peer *Peer) keepKeyFreshSending() {
+	keypair := peer.keypairs.Current()
+	if keypair == nil {
+		return
+	}
+	nonce := atomic.LoadUint64(&keypair.sendNonce)
+	if nonce > RekeyAfterMessages || (keypair.isInitiator && time.Now().Sub(keypair.created) > RekeyAfterTime) {
+		peer.SendHandshakeInitiation(false)
+	}
+}
+
+/* Reads packets from the TUN and inserts
+ * into nonce queue for peer
+ *
+ * Obs. Single instance per TUN device
+ */
+func (device *Device) RoutineReadFromTUN() {
+
+	logDebug := device.log.Debug
+	logError := device.log.Error
+
+	defer func() {
+		logDebug.Println("Routine: TUN reader - stopped")
+		device.state.stopping.Done()
+	}()
+
+	logDebug.Println("Routine: TUN reader - started")
+	device.state.starting.Done()
+
+	var elem *QueueOutboundElement
+
+	for {
+		if elem != nil {
+			device.PutMessageBuffer(elem.buffer)
+			device.PutOutboundElement(elem)
+		}
+		elem = device.NewOutboundElement()
+
+		// read packet
+
+		offset := MessageTransportHeaderSize
+		size, err := device.tun.device.Read(elem.buffer[:], offset)
+
+		if err != nil {
+			if !device.isClosed.Get() {
+				logError.Println("Failed to read packet from TUN device:", err)
+				device.Close()
+			}
+			device.PutMessageBuffer(elem.buffer)
+			device.PutOutboundElement(elem)
+			return
+		}
+
+		if size == 0 || size > MaxContentSize {
+			continue
+		}
+
+		elem.packet = elem.buffer[offset : offset+size]
+
+		// lookup peer
+
+		var peer *Peer
+		switch elem.packet[0] >> 4 {
+		case ipv4.Version:
+			if len(elem.packet) < ipv4.HeaderLen {
+				continue
+			}
+			dst := elem.packet[IPv4offsetDst : IPv4offsetDst+net.IPv4len]
+			peer = device.allowedips.LookupIPv4(dst)
+
+		case ipv6.Version:
+			if len(elem.packet) < ipv6.HeaderLen {
+				continue
+			}
+			dst := elem.packet[IPv6offsetDst : IPv6offsetDst+net.IPv6len]
+			peer = device.allowedips.LookupIPv6(dst)
+
+		default:
+			logDebug.Println("Received packet with unknown IP version")
+		}
+
+		if peer == nil {
+			continue
+		}
+
+		// insert into nonce/pre-handshake queue
+
+		if peer.isRunning.Get() {
+			if peer.queue.packetInNonceQueueIsAwaitingKey.Get() {
+				peer.SendHandshakeInitiation(false)
+			}
+			addToNonceQueue(peer.queue.nonce, elem, device)
+			elem = nil
+		}
+	}
+}
+
+func (peer *Peer) FlushNonceQueue() {
+	select {
+	case peer.signals.flushNonceQueue <- struct{}{}:
+	default:
+	}
+}
+
+/* Queues packets when there is no handshake.
+ * Then assigns nonces to packets sequentially
+ * and creates "work" structs for workers
+ *
+ * Obs. A single instance per peer
+ */
+func (peer *Peer) RoutineNonce() {
+	var keypair *Keypair
+
+	device := peer.device
+	logDebug := device.log.Debug
+
+	flush := func() {
+		for {
+			select {
+			case elem := <-peer.queue.nonce:
+				device.PutMessageBuffer(elem.buffer)
+				device.PutOutboundElement(elem)
+			default:
+				return
+			}
+		}
+	}
+
+	defer func() {
+		flush()
+		logDebug.Println(peer, "- Routine: nonce worker - stopped")
+		peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
+		peer.routines.stopping.Done()
+	}()
+
+	peer.routines.starting.Done()
+	logDebug.Println(peer, "- Routine: nonce worker - started")
+
+	for {
+	NextPacket:
+		peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
+
+		select {
+		case <-peer.routines.stop:
+			return
+
+		case <-peer.signals.flushNonceQueue:
+			flush()
+			goto NextPacket
+
+		case elem, ok := <-peer.queue.nonce:
+
+			if !ok {
+				return
+			}
+
+			// make sure to always pick the newest key
+
+			for {
+
+				// check validity of newest key pair
+
+				keypair = peer.keypairs.Current()
+				if keypair != nil && keypair.sendNonce < RejectAfterMessages {
+					if time.Now().Sub(keypair.created) < RejectAfterTime {
+						break
+					}
+				}
+				peer.queue.packetInNonceQueueIsAwaitingKey.Set(true)
+
+				// no suitable key pair, request for new handshake
+
+				select {
+				case <-peer.signals.newKeypairArrived:
+				default:
+				}
+
+				peer.SendHandshakeInitiation(false)
+
+				// wait for key to be established
+
+				logDebug.Println(peer, "- Awaiting keypair")
+
+				select {
+				case <-peer.signals.newKeypairArrived:
+					logDebug.Println(peer, "- Obtained awaited keypair")
+
+				case <-peer.signals.flushNonceQueue:
+					device.PutMessageBuffer(elem.buffer)
+					device.PutOutboundElement(elem)
+					flush()
+					goto NextPacket
+
+				case <-peer.routines.stop:
+					device.PutMessageBuffer(elem.buffer)
+					device.PutOutboundElement(elem)
+					return
+				}
+			}
+			peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
+
+			// populate work element
+
+			elem.peer = peer
+			elem.nonce = atomic.AddUint64(&keypair.sendNonce, 1) - 1
+
+			// double check in case of race condition added by future code
+
+			if elem.nonce >= RejectAfterMessages {
+				atomic.StoreUint64(&keypair.sendNonce, RejectAfterMessages)
+				device.PutMessageBuffer(elem.buffer)
+				device.PutOutboundElement(elem)
+				goto NextPacket
+			}
+
+			elem.keypair = keypair
+			elem.dropped = AtomicFalse
+			elem.Lock()
+
+			// add to parallel and sequential queue
+			addToOutboundAndEncryptionQueues(peer.queue.outbound, device.queue.encryption, elem)
+		}
+	}
+}
+
+/* Encrypts the elements in the queue
+ * and marks them for sequential consumption (by releasing the mutex)
+ *
+ * Obs. One instance per core
+ */
+func (device *Device) RoutineEncryption() {
+
+	var nonce [chacha20poly1305.NonceSize]byte
+
+	logDebug := device.log.Debug
+
+	defer func() {
+		for {
+			select {
+			case elem, ok := <-device.queue.encryption:
+				if ok && !elem.IsDropped() {
+					elem.Drop()
+					device.PutMessageBuffer(elem.buffer)
+					elem.Unlock()
+				}
+			default:
+				goto out
+			}
+		}
+	out:
+		logDebug.Println("Routine: encryption worker - stopped")
+		device.state.stopping.Done()
+	}()
+
+	logDebug.Println("Routine: encryption worker - started")
+	device.state.starting.Done()
+
+	for {
+
+		// fetch next element
+
+		select {
+		case <-device.signals.stop:
+			return
+
+		case elem, ok := <-device.queue.encryption:
+
+			if !ok {
+				return
+			}
+
+			// check if dropped
+
+			if elem.IsDropped() {
+				continue
+			}
+
+			// populate header fields
+
+			header := elem.buffer[:MessageTransportHeaderSize]
+
+			fieldType := header[0:4]
+			fieldReceiver := header[4:8]
+			fieldNonce := header[8:16]
+
+			binary.LittleEndian.PutUint32(fieldType, MessageTransportType)
+			binary.LittleEndian.PutUint32(fieldReceiver, elem.keypair.remoteIndex)
+			binary.LittleEndian.PutUint64(fieldNonce, elem.nonce)
+
+			// pad content to multiple of 16
+
+			mtu := int(atomic.LoadInt32(&device.tun.mtu))
+			lastUnit := len(elem.packet) % mtu
+			paddedSize := (lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1)
+			if paddedSize > mtu {
+				paddedSize = mtu
+			}
+			for i := len(elem.packet); i < paddedSize; i++ {
+				elem.packet = append(elem.packet, 0)
+			}
+
+			// encrypt content and release to consumer
+
+			binary.LittleEndian.PutUint64(nonce[4:], elem.nonce)
+			elem.packet = elem.keypair.send.Seal(
+				header,
+				nonce[:],
+				elem.packet,
+				nil,
+			)
+			elem.Unlock()
+		}
+	}
+}
+
+/* Sequentially reads packets from queue and sends to endpoint
+ *
+ * Obs. Single instance per peer.
+ * The routine terminates then the outbound queue is closed.
+ */
+func (peer *Peer) RoutineSequentialSender() {
+
+	device := peer.device
+
+	logDebug := device.log.Debug
+	logError := device.log.Error
+
+	defer func() {
+		for {
+			select {
+			case elem, ok := <-peer.queue.outbound:
+				if ok {
+					if !elem.IsDropped() {
+						device.PutMessageBuffer(elem.buffer)
+						elem.Drop()
+					}
+					device.PutOutboundElement(elem)
+				}
+			default:
+				goto out
+			}
+		}
+	out:
+		logDebug.Println(peer, "- Routine: sequential sender - stopped")
+		peer.routines.stopping.Done()
+	}()
+
+	logDebug.Println(peer, "- Routine: sequential sender - started")
+
+	peer.routines.starting.Done()
+
+	for {
+		select {
+
+		case <-peer.routines.stop:
+			return
+
+		case elem, ok := <-peer.queue.outbound:
+
+			if !ok {
+				return
+			}
+
+			elem.Lock()
+			if elem.IsDropped() {
+				device.PutOutboundElement(elem)
+				continue
+			}
+
+			peer.timersAnyAuthenticatedPacketTraversal()
+			peer.timersAnyAuthenticatedPacketSent()
+
+			// send message and return buffer to pool
+
+			length := uint64(len(elem.packet))
+			err := peer.SendBuffer(elem.packet)
+			device.PutMessageBuffer(elem.buffer)
+			device.PutOutboundElement(elem)
+			if err != nil {
+				logError.Println(peer, "- Failed to send data packet", err)
+				continue
+			}
+			atomic.AddUint64(&peer.stats.txBytes, length)
+
+			if len(elem.packet) != MessageKeepaliveSize {
+				peer.timersDataSent()
+			}
+			peer.keepKeyFreshSending()
+		}
+	}
+}
diff --git a/device/timers.go b/device/timers.go
new file mode 100644
index 0000000..5f28fcc
--- /dev/null
+++ b/device/timers.go
@@ -0,0 +1,227 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ *
+ * This is based heavily on timers.c from the kernel implementation.
+ */
+
+package device
+
+import (
+	"math/rand"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+/* This Timer structure and related functions should roughly copy the interface of
+ * the Linux kernel's struct timer_list.
+ */
+
+type Timer struct {
+	*time.Timer
+	modifyingLock sync.RWMutex
+	runningLock   sync.Mutex
+	isPending     bool
+}
+
+func (peer *Peer) NewTimer(expirationFunction func(*Peer)) *Timer {
+	timer := &Timer{}
+	timer.Timer = time.AfterFunc(time.Hour, func() {
+		timer.runningLock.Lock()
+
+		timer.modifyingLock.Lock()
+		if !timer.isPending {
+			timer.modifyingLock.Unlock()
+			timer.runningLock.Unlock()
+			return
+		}
+		timer.isPending = false
+		timer.modifyingLock.Unlock()
+
+		expirationFunction(peer)
+		timer.runningLock.Unlock()
+	})
+	timer.Stop()
+	return timer
+}
+
+func (timer *Timer) Mod(d time.Duration) {
+	timer.modifyingLock.Lock()
+	timer.isPending = true
+	timer.Reset(d)
+	timer.modifyingLock.Unlock()
+}
+
+func (timer *Timer) Del() {
+	timer.modifyingLock.Lock()
+	timer.isPending = false
+	timer.Stop()
+	timer.modifyingLock.Unlock()
+}
+
+func (timer *Timer) DelSync() {
+	timer.Del()
+	timer.runningLock.Lock()
+	timer.Del()
+	timer.runningLock.Unlock()
+}
+
+func (timer *Timer) IsPending() bool {
+	timer.modifyingLock.RLock()
+	defer timer.modifyingLock.RUnlock()
+	return timer.isPending
+}
+
+func (peer *Peer) timersActive() bool {
+	return peer.isRunning.Get() && peer.device != nil && peer.device.isUp.Get() && len(peer.device.peers.keyMap) > 0
+}
+
+func expiredRetransmitHandshake(peer *Peer) {
+	if atomic.LoadUint32(&peer.timers.handshakeAttempts) > MaxTimerHandshakes {
+		peer.device.log.Debug.Printf("%s - Handshake did not complete after %d attempts, giving up\n", peer, MaxTimerHandshakes+2)
+
+		if peer.timersActive() {
+			peer.timers.sendKeepalive.Del()
+		}
+
+		/* We drop all packets without a keypair and don't try again,
+		 * if we try unsuccessfully for too long to make a handshake.
+		 */
+		peer.FlushNonceQueue()
+
+		/* We set a timer for destroying any residue that might be left
+		 * of a partial exchange.
+		 */
+		if peer.timersActive() && !peer.timers.zeroKeyMaterial.IsPending() {
+			peer.timers.zeroKeyMaterial.Mod(RejectAfterTime * 3)
+		}
+	} else {
+		atomic.AddUint32(&peer.timers.handshakeAttempts, 1)
+		peer.device.log.Debug.Printf("%s - Handshake did not complete after %d seconds, retrying (try %d)\n", peer, int(RekeyTimeout.Seconds()), atomic.LoadUint32(&peer.timers.handshakeAttempts)+1)
+
+		/* We clear the endpoint address src address, in case this is the cause of trouble. */
+		peer.Lock()
+		if peer.endpoint != nil {
+			peer.endpoint.ClearSrc()
+		}
+		peer.Unlock()
+
+		peer.SendHandshakeInitiation(true)
+	}
+}
+
+func expiredSendKeepalive(peer *Peer) {
+	peer.SendKeepalive()
+	if peer.timers.needAnotherKeepalive.Get() {
+		peer.timers.needAnotherKeepalive.Set(false)
+		if peer.timersActive() {
+			peer.timers.sendKeepalive.Mod(KeepaliveTimeout)
+		}
+	}
+}
+
+func expiredNewHandshake(peer *Peer) {
+	peer.device.log.Debug.Printf("%s - Retrying handshake because we stopped hearing back after %d seconds\n", peer, int((KeepaliveTimeout + RekeyTimeout).Seconds()))
+	/* We clear the endpoint address src address, in case this is the cause of trouble. */
+	peer.Lock()
+	if peer.endpoint != nil {
+		peer.endpoint.ClearSrc()
+	}
+	peer.Unlock()
+	peer.SendHandshakeInitiation(false)
+
+}
+
+func expiredZeroKeyMaterial(peer *Peer) {
+	peer.device.log.Debug.Printf("%s - Removing all keys, since we haven't received a new one in %d seconds\n", peer, int((RejectAfterTime * 3).Seconds()))
+	peer.ZeroAndFlushAll()
+}
+
+func expiredPersistentKeepalive(peer *Peer) {
+	if peer.persistentKeepaliveInterval > 0 {
+		peer.SendKeepalive()
+	}
+}
+
+/* Should be called after an authenticated data packet is sent. */
+func (peer *Peer) timersDataSent() {
+	if peer.timersActive() && !peer.timers.newHandshake.IsPending() {
+		peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout)
+	}
+}
+
+/* Should be called after an authenticated data packet is received. */
+func (peer *Peer) timersDataReceived() {
+	if peer.timersActive() {
+		if !peer.timers.sendKeepalive.IsPending() {
+			peer.timers.sendKeepalive.Mod(KeepaliveTimeout)
+		} else {
+			peer.timers.needAnotherKeepalive.Set(true)
+		}
+	}
+}
+
+/* Should be called after any type of authenticated packet is sent -- keepalive, data, or handshake. */
+func (peer *Peer) timersAnyAuthenticatedPacketSent() {
+	if peer.timersActive() {
+		peer.timers.sendKeepalive.Del()
+	}
+}
+
+/* Should be called after any type of authenticated packet is received -- keepalive, data, or handshake. */
+func (peer *Peer) timersAnyAuthenticatedPacketReceived() {
+	if peer.timersActive() {
+		peer.timers.newHandshake.Del()
+	}
+}
+
+/* Should be called after a handshake initiation message is sent. */
+func (peer *Peer) timersHandshakeInitiated() {
+	if peer.timersActive() {
+		peer.timers.retransmitHandshake.Mod(RekeyTimeout + time.Millisecond*time.Duration(rand.Int31n(RekeyTimeoutJitterMaxMs)))
+	}
+}
+
+/* Should be called after a handshake response message is received and processed or when getting key confirmation via the first data message. */
+func (peer *Peer) timersHandshakeComplete() {
+	if peer.timersActive() {
+		peer.timers.retransmitHandshake.Del()
+	}
+	atomic.StoreUint32(&peer.timers.handshakeAttempts, 0)
+	peer.timers.sentLastMinuteHandshake.Set(false)
+	atomic.StoreInt64(&peer.stats.lastHandshakeNano, time.Now().UnixNano())
+}
+
+/* Should be called after an ephemeral key is created, which is before sending a handshake response or after receiving a handshake response. */
+func (peer *Peer) timersSessionDerived() {
+	if peer.timersActive() {
+		peer.timers.zeroKeyMaterial.Mod(RejectAfterTime * 3)
+	}
+}
+
+/* Should be called before a packet with authentication -- keepalive, data, or handshake -- is sent, or after one is received. */
+func (peer *Peer) timersAnyAuthenticatedPacketTraversal() {
+	if peer.persistentKeepaliveInterval > 0 && peer.timersActive() {
+		peer.timers.persistentKeepalive.Mod(time.Duration(peer.persistentKeepaliveInterval) * time.Second)
+	}
+}
+
+func (peer *Peer) timersInit() {
+	peer.timers.retransmitHandshake = peer.NewTimer(expiredRetransmitHandshake)
+	peer.timers.sendKeepalive = peer.NewTimer(expiredSendKeepalive)
+	peer.timers.newHandshake = peer.NewTimer(expiredNewHandshake)
+	peer.timers.zeroKeyMaterial = peer.NewTimer(expiredZeroKeyMaterial)
+	peer.timers.persistentKeepalive = peer.NewTimer(expiredPersistentKeepalive)
+	atomic.StoreUint32(&peer.timers.handshakeAttempts, 0)
+	peer.timers.sentLastMinuteHandshake.Set(false)
+	peer.timers.needAnotherKeepalive.Set(false)
+}
+
+func (peer *Peer) timersStop() {
+	peer.timers.retransmitHandshake.DelSync()
+	peer.timers.sendKeepalive.DelSync()
+	peer.timers.newHandshake.DelSync()
+	peer.timers.zeroKeyMaterial.DelSync()
+	peer.timers.persistentKeepalive.DelSync()
+}
diff --git a/device/tun.go b/device/tun.go
new file mode 100644
index 0000000..bc5f1f1
--- /dev/null
+++ b/device/tun.go
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"golang.zx2c4.com/wireguard/tun"
+	"sync/atomic"
+)
+
+const DefaultMTU = 1420
+
+func (device *Device) RoutineTUNEventReader() {
+	setUp := false
+	logDebug := device.log.Debug
+	logInfo := device.log.Info
+	logError := device.log.Error
+
+	logDebug.Println("Routine: event worker - started")
+	device.state.starting.Done()
+
+	for event := range device.tun.device.Events() {
+		if event&tun.TUNEventMTUUpdate != 0 {
+			mtu, err := device.tun.device.MTU()
+			old := atomic.LoadInt32(&device.tun.mtu)
+			if err != nil {
+				logError.Println("Failed to load updated MTU of device:", err)
+			} else if int(old) != mtu {
+				if mtu+MessageTransportSize > MaxMessageSize {
+					logInfo.Println("MTU updated:", mtu, "(too large)")
+				} else {
+					logInfo.Println("MTU updated:", mtu)
+				}
+				atomic.StoreInt32(&device.tun.mtu, int32(mtu))
+			}
+		}
+
+		if event&tun.TUNEventUp != 0 && !setUp {
+			logInfo.Println("Interface set up")
+			setUp = true
+			device.Up()
+		}
+
+		if event&tun.TUNEventDown != 0 && setUp {
+			logInfo.Println("Interface set down")
+			setUp = false
+			device.Down()
+		}
+	}
+
+	logDebug.Println("Routine: event worker - stopped")
+	device.state.stopping.Done()
+}
diff --git a/device/uapi.go b/device/uapi.go
new file mode 100644
index 0000000..5c65917
--- /dev/null
+++ b/device/uapi.go
@@ -0,0 +1,426 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"bufio"
+	"fmt"
+	"golang.zx2c4.com/wireguard/ipc"
+	"io"
+	"net"
+	"strconv"
+	"strings"
+	"sync/atomic"
+	"time"
+)
+
+type IPCError struct {
+	int64
+}
+
+func (s *IPCError) Error() string {
+	return fmt.Sprintf("IPC error: %d", s.int64)
+}
+
+func (s *IPCError) ErrorCode() int64 {
+	return s.int64
+}
+
+func (device *Device) IpcGetOperation(socket *bufio.Writer) *IPCError {
+
+	device.log.Debug.Println("UAPI: Processing get operation")
+
+	// create lines
+
+	lines := make([]string, 0, 100)
+	send := func(line string) {
+		lines = append(lines, line)
+	}
+
+	func() {
+
+		// lock required resources
+
+		device.net.RLock()
+		defer device.net.RUnlock()
+
+		device.staticIdentity.RLock()
+		defer device.staticIdentity.RUnlock()
+
+		device.peers.RLock()
+		defer device.peers.RUnlock()
+
+		// serialize device related values
+
+		if !device.staticIdentity.privateKey.IsZero() {
+			send("private_key=" + device.staticIdentity.privateKey.ToHex())
+		}
+
+		if device.net.port != 0 {
+			send(fmt.Sprintf("listen_port=%d", device.net.port))
+		}
+
+		if device.net.fwmark != 0 {
+			send(fmt.Sprintf("fwmark=%d", device.net.fwmark))
+		}
+
+		// serialize each peer state
+
+		for _, peer := range device.peers.keyMap {
+			peer.RLock()
+			defer peer.RUnlock()
+
+			send("public_key=" + peer.handshake.remoteStatic.ToHex())
+			send("preshared_key=" + peer.handshake.presharedKey.ToHex())
+			send("protocol_version=1")
+			if peer.endpoint != nil {
+				send("endpoint=" + peer.endpoint.DstToString())
+			}
+
+			nano := atomic.LoadInt64(&peer.stats.lastHandshakeNano)
+			secs := nano / time.Second.Nanoseconds()
+			nano %= time.Second.Nanoseconds()
+
+			send(fmt.Sprintf("last_handshake_time_sec=%d", secs))
+			send(fmt.Sprintf("last_handshake_time_nsec=%d", nano))
+			send(fmt.Sprintf("tx_bytes=%d", atomic.LoadUint64(&peer.stats.txBytes)))
+			send(fmt.Sprintf("rx_bytes=%d", atomic.LoadUint64(&peer.stats.rxBytes)))
+			send(fmt.Sprintf("persistent_keepalive_interval=%d", peer.persistentKeepaliveInterval))
+
+			for _, ip := range device.allowedips.EntriesForPeer(peer) {
+				send("allowed_ip=" + ip.String())
+			}
+
+		}
+	}()
+
+	// send lines (does not require resource locks)
+
+	for _, line := range lines {
+		_, err := socket.WriteString(line + "\n")
+		if err != nil {
+			return &IPCError{ipc.IpcErrorIO}
+		}
+	}
+
+	return nil
+}
+
+func (device *Device) IpcSetOperation(socket *bufio.Reader) *IPCError {
+	scanner := bufio.NewScanner(socket)
+	logError := device.log.Error
+	logDebug := device.log.Debug
+
+	var peer *Peer
+
+	dummy := false
+	deviceConfig := true
+
+	for scanner.Scan() {
+
+		// parse line
+
+		line := scanner.Text()
+		if line == "" {
+			return nil
+		}
+		parts := strings.Split(line, "=")
+		if len(parts) != 2 {
+			return &IPCError{ipc.IpcErrorProtocol}
+		}
+		key := parts[0]
+		value := parts[1]
+
+		/* device configuration */
+
+		if deviceConfig {
+
+			switch key {
+			case "private_key":
+				var sk NoisePrivateKey
+				err := sk.FromHex(value)
+				if err != nil {
+					logError.Println("Failed to set private_key:", err)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+				logDebug.Println("UAPI: Updating private key")
+				device.SetPrivateKey(sk)
+
+			case "listen_port":
+
+				// parse port number
+
+				port, err := strconv.ParseUint(value, 10, 16)
+				if err != nil {
+					logError.Println("Failed to parse listen_port:", err)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+				// update port and rebind
+
+				logDebug.Println("UAPI: Updating listen port")
+
+				device.net.Lock()
+				device.net.port = uint16(port)
+				device.net.Unlock()
+
+				if err := device.BindUpdate(); err != nil {
+					logError.Println("Failed to set listen_port:", err)
+					return &IPCError{ipc.IpcErrorPortInUse}
+				}
+
+			case "fwmark":
+
+				// parse fwmark field
+
+				fwmark, err := func() (uint32, error) {
+					if value == "" {
+						return 0, nil
+					}
+					mark, err := strconv.ParseUint(value, 10, 32)
+					return uint32(mark), err
+				}()
+
+				if err != nil {
+					logError.Println("Invalid fwmark", err)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+				logDebug.Println("UAPI: Updating fwmark")
+
+				if err := device.BindSetMark(uint32(fwmark)); err != nil {
+					logError.Println("Failed to update fwmark:", err)
+					return &IPCError{ipc.IpcErrorPortInUse}
+				}
+
+			case "public_key":
+				// switch to peer configuration
+				logDebug.Println("UAPI: Transition to peer configuration")
+				deviceConfig = false
+
+			case "replace_peers":
+				if value != "true" {
+					logError.Println("Failed to set replace_peers, invalid value:", value)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+				logDebug.Println("UAPI: Removing all peers")
+				device.RemoveAllPeers()
+
+			default:
+				logError.Println("Invalid UAPI device key:", key)
+				return &IPCError{ipc.IpcErrorInvalid}
+			}
+		}
+
+		/* peer configuration */
+
+		if !deviceConfig {
+
+			switch key {
+
+			case "public_key":
+				var publicKey NoisePublicKey
+				err := publicKey.FromHex(value)
+				if err != nil {
+					logError.Println("Failed to get peer by public key:", err)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+				// ignore peer with public key of device
+
+				device.staticIdentity.RLock()
+				dummy = device.staticIdentity.publicKey.Equals(publicKey)
+				device.staticIdentity.RUnlock()
+
+				if dummy {
+					peer = &Peer{}
+				} else {
+					peer = device.LookupPeer(publicKey)
+				}
+
+				if peer == nil {
+					peer, err = device.NewPeer(publicKey)
+					if err != nil {
+						logError.Println("Failed to create new peer:", err)
+						return &IPCError{ipc.IpcErrorInvalid}
+					}
+					logDebug.Println(peer, "- UAPI: Created")
+				}
+
+			case "remove":
+
+				// remove currently selected peer from device
+
+				if value != "true" {
+					logError.Println("Failed to set remove, invalid value:", value)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+				if !dummy {
+					logDebug.Println(peer, "- UAPI: Removing")
+					device.RemovePeer(peer.handshake.remoteStatic)
+				}
+				peer = &Peer{}
+				dummy = true
+
+			case "preshared_key":
+
+				// update PSK
+
+				logDebug.Println(peer, "- UAPI: Updating preshared key")
+
+				peer.handshake.mutex.Lock()
+				err := peer.handshake.presharedKey.FromHex(value)
+				peer.handshake.mutex.Unlock()
+
+				if err != nil {
+					logError.Println("Failed to set preshared key:", err)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+			case "endpoint":
+
+				// set endpoint destination
+
+				logDebug.Println(peer, "- UAPI: Updating endpoint")
+
+				err := func() error {
+					peer.Lock()
+					defer peer.Unlock()
+					endpoint, err := CreateEndpoint(value)
+					if err != nil {
+						return err
+					}
+					peer.endpoint = endpoint
+					return nil
+				}()
+
+				if err != nil {
+					logError.Println("Failed to set endpoint:", value)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+			case "persistent_keepalive_interval":
+
+				// update persistent keepalive interval
+
+				logDebug.Println(peer, "- UAPI: Updating persistent keepalive interval")
+
+				secs, err := strconv.ParseUint(value, 10, 16)
+				if err != nil {
+					logError.Println("Failed to set persistent keepalive interval:", err)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+				old := peer.persistentKeepaliveInterval
+				peer.persistentKeepaliveInterval = uint16(secs)
+
+				// send immediate keepalive if we're turning it on and before it wasn't on
+
+				if old == 0 && secs != 0 {
+					if err != nil {
+						logError.Println("Failed to get tun device status:", err)
+						return &IPCError{ipc.IpcErrorIO}
+					}
+					if device.isUp.Get() && !dummy {
+						peer.SendKeepalive()
+					}
+				}
+
+			case "replace_allowed_ips":
+
+				logDebug.Println(peer, "- UAPI: Removing all allowedips")
+
+				if value != "true" {
+					logError.Println("Failed to replace allowedips, invalid value:", value)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+				if dummy {
+					continue
+				}
+
+				device.allowedips.RemoveByPeer(peer)
+
+			case "allowed_ip":
+
+				logDebug.Println(peer, "- UAPI: Adding allowedip")
+
+				_, network, err := net.ParseCIDR(value)
+				if err != nil {
+					logError.Println("Failed to set allowed ip:", err)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+				if dummy {
+					continue
+				}
+
+				ones, _ := network.Mask.Size()
+				device.allowedips.Insert(network.IP, uint(ones), peer)
+
+			case "protocol_version":
+
+				if value != "1" {
+					logError.Println("Invalid protocol version:", value)
+					return &IPCError{ipc.IpcErrorInvalid}
+				}
+
+			default:
+				logError.Println("Invalid UAPI peer key:", key)
+				return &IPCError{ipc.IpcErrorInvalid}
+			}
+		}
+	}
+
+	return nil
+}
+
+func (device *Device) IpcHandle(socket net.Conn) {
+
+	// create buffered read/writer
+
+	defer socket.Close()
+
+	buffered := func(s io.ReadWriter) *bufio.ReadWriter {
+		reader := bufio.NewReader(s)
+		writer := bufio.NewWriter(s)
+		return bufio.NewReadWriter(reader, writer)
+	}(socket)
+
+	defer buffered.Flush()
+
+	op, err := buffered.ReadString('\n')
+	if err != nil {
+		return
+	}
+
+	// handle operation
+
+	var status *IPCError
+
+	switch op {
+	case "set=1\n":
+		device.log.Debug.Println("UAPI: Set operation")
+		status = device.IpcSetOperation(buffered.Reader)
+
+	case "get=1\n":
+		device.log.Debug.Println("UAPI: Get operation")
+		status = device.IpcGetOperation(buffered.Writer)
+
+	default:
+		device.log.Error.Println("Invalid UAPI operation:", op)
+		return
+	}
+
+	// write status
+
+	if status != nil {
+		device.log.Error.Println(status)
+		fmt.Fprintf(buffered, "errno=%d\n\n", status.ErrorCode())
+	} else {
+		fmt.Fprintf(buffered, "errno=0\n\n")
+	}
+}
diff --git a/device/version.go b/device/version.go
new file mode 100644
index 0000000..9077cdc
--- /dev/null
+++ b/device/version.go
@@ -0,0 +1,3 @@
+package device
+
+const WireGuardGoVersion = "0.0.20181222"