device: test packets between two fake devices
Signed-off-by: David Crawshaw <crawshaw@tailscale.io>
This commit is contained in:
David Crawshaw
Jason A. Donenfeld
parent
f2ea85e9f9
commit
540d01e54a
@ -5,54 +5,212 @@
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package device
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/* Create two device instances and simulate full WireGuard interaction
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* without network dependencies
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*/
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import (
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"bufio"
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"bytes"
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"encoding/binary"
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"io"
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"net"
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"os"
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"strings"
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"testing"
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"time"
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"golang.zx2c4.com/wireguard/tun"
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)
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func TestDevice(t *testing.T) {
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// prepare tun devices for generating traffic
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tun1 := newDummyTUN("tun1")
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tun2 := newDummyTUN("tun2")
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_ = tun1
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_ = tun2
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// prepare endpoints
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end1, err := CreateDummyEndpoint()
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if err != nil {
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t.Error("failed to create endpoint:", err.Error())
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}
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end2, err := CreateDummyEndpoint()
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if err != nil {
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t.Error("failed to create endpoint:", err.Error())
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}
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_ = end1
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_ = end2
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// create binds
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}
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func randDevice(t *testing.T) *Device {
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sk, err := newPrivateKey()
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if err != nil {
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func TestTwoDevicePing(t *testing.T) {
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// TODO(crawshaw): pick unused ports on localhost
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cfg1 := `private_key=481eb0d8113a4a5da532d2c3e9c14b53c8454b34ab109676f6b58c2245e37b58
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listen_port=53511
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replace_peers=true
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public_key=f70dbb6b1b92a1dde1c783b297016af3f572fef13b0abb16a2623d89a58e9725
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protocol_version=1
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replace_allowed_ips=true
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allowed_ip=1.0.0.2/32
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endpoint=127.0.0.1:53512`
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tun1 := NewChannelTUN()
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dev1 := NewDevice(tun1.TUN(), NewLogger(LogLevelDebug, "dev1: "))
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dev1.Up()
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defer dev1.Close()
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if err := dev1.IpcSetOperation(bufio.NewReader(strings.NewReader(cfg1))); err != nil {
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t.Fatal(err)
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}
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tun := newDummyTUN("dummy")
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logger := NewLogger(LogLevelError, "")
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device := NewDevice(tun, logger)
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device.SetPrivateKey(sk)
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return device
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cfg2 := `private_key=98c7989b1661a0d64fd6af3502000f87716b7c4bbcf00d04fc6073aa7b539768
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listen_port=53512
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replace_peers=true
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public_key=49e80929259cebdda4f322d6d2b1a6fad819d603acd26fd5d845e7a123036427
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protocol_version=1
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replace_allowed_ips=true
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allowed_ip=1.0.0.1/32
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endpoint=127.0.0.1:53511`
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tun2 := NewChannelTUN()
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dev2 := NewDevice(tun2.TUN(), NewLogger(LogLevelDebug, "dev2: "))
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dev2.Up()
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defer dev2.Close()
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if err := dev2.IpcSetOperation(bufio.NewReader(strings.NewReader(cfg2))); err != nil {
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t.Fatal(err)
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}
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t.Run("ping 1.0.0.1", func(t *testing.T) {
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msg2to1 := ping(net.ParseIP("1.0.0.1"), net.ParseIP("1.0.0.2"))
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tun2.Outbound <- msg2to1
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select {
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case msgRecv := <-tun1.Inbound:
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if !bytes.Equal(msg2to1, msgRecv) {
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t.Error("ping did not transit correctly")
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}
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case <-time.After(300 * time.Millisecond):
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t.Error("ping did not transit")
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}
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})
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t.Run("ping 1.0.0.2", func(t *testing.T) {
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msg1to2 := ping(net.ParseIP("1.0.0.2"), net.ParseIP("1.0.0.1"))
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tun1.Outbound <- msg1to2
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select {
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case msgRecv := <-tun2.Inbound:
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if !bytes.Equal(msg1to2, msgRecv) {
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t.Error("return ping did not transit correctly")
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}
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case <-time.After(300 * time.Millisecond):
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t.Error("return ping did not transit")
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}
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})
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}
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func ping(dst, src net.IP) []byte {
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localPort := uint16(1337)
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seq := uint16(0)
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payload := make([]byte, 4)
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binary.BigEndian.PutUint16(payload[0:], localPort)
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binary.BigEndian.PutUint16(payload[2:], seq)
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return genICMPv4(payload, dst, src)
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}
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// checksum is the "internet checksum" from https://tools.ietf.org/html/rfc1071.
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func checksum(buf []byte, initial uint16) uint16 {
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v := uint32(initial)
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for i := 0; i < len(buf)-1; i += 2 {
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v += uint32(binary.BigEndian.Uint16(buf[i:]))
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}
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if len(buf)%2 == 1 {
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v += uint32(buf[len(buf)-1]) << 8
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}
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for v > 0xffff {
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v = (v >> 16) + (v & 0xffff)
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}
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return ^uint16(v)
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}
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func genICMPv4(payload []byte, dst, src net.IP) []byte {
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const (
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icmpv4ProtocolNumber = 1
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icmpv4Echo = 8
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icmpv4ChecksumOffset = 2
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icmpv4Size = 8
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ipv4Size = 20
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ipv4TotalLenOffset = 2
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ipv4ChecksumOffset = 10
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ttl = 65
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)
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hdr := make([]byte, ipv4Size+icmpv4Size)
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ip := hdr[0:ipv4Size]
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icmpv4 := hdr[ipv4Size : ipv4Size+icmpv4Size]
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// https://tools.ietf.org/html/rfc792
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icmpv4[0] = icmpv4Echo // type
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icmpv4[1] = 0 // code
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chksum := ^checksum(icmpv4, checksum(payload, 0))
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binary.BigEndian.PutUint16(icmpv4[icmpv4ChecksumOffset:], chksum)
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// https://tools.ietf.org/html/rfc760 section 3.1
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length := uint16(len(hdr) + len(payload))
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ip[0] = (4 << 4) | (ipv4Size / 4)
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binary.BigEndian.PutUint16(ip[ipv4TotalLenOffset:], length)
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ip[8] = ttl
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ip[9] = icmpv4ProtocolNumber
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copy(ip[12:], src.To4())
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copy(ip[16:], dst.To4())
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chksum = ^checksum(ip[:], 0)
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binary.BigEndian.PutUint16(ip[ipv4ChecksumOffset:], chksum)
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var v []byte
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v = append(v, hdr...)
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v = append(v, payload...)
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return []byte(v)
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}
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// TODO(crawshaw): find a reusable home for this. package devicetest?
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type ChannelTUN struct {
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Inbound chan []byte // incoming packets, closed on TUN close
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Outbound chan []byte // outbound packets, blocks forever on TUN close
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closed chan struct{}
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events chan tun.Event
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tun chTun
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}
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func NewChannelTUN() *ChannelTUN {
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c := &ChannelTUN{
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Inbound: make(chan []byte),
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Outbound: make(chan []byte),
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closed: make(chan struct{}),
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events: make(chan tun.Event, 1),
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}
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c.tun.c = c
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c.events <- tun.EventUp
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return c
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}
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func (c *ChannelTUN) TUN() tun.Device {
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return &c.tun
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}
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type chTun struct {
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c *ChannelTUN
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}
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func (t *chTun) File() *os.File { return nil }
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func (t *chTun) Read(data []byte, offset int) (int, error) {
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select {
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case <-t.c.closed:
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return 0, io.EOF // TODO(crawshaw): what is the correct error value?
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case msg := <-t.c.Outbound:
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return copy(data[offset:], msg), nil
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}
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}
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// Write is called by the wireguard device to deliver a packet for routing.
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func (t *chTun) Write(data []byte, offset int) (int, error) {
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if offset == -1 {
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close(t.c.closed)
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close(t.c.events)
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return 0, io.EOF
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}
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msg := make([]byte, len(data)-offset)
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copy(msg, data[offset:])
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select {
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case <-t.c.closed:
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return 0, io.EOF // TODO(crawshaw): what is the correct error value?
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case t.c.Inbound <- msg:
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return len(data) - offset, nil
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}
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}
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func (t *chTun) Flush() error { return nil }
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func (t *chTun) MTU() (int, error) { return DefaultMTU, nil }
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func (t *chTun) Name() (string, error) { return "loopbackTun1", nil }
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func (t *chTun) Events() chan tun.Event { return t.c.events }
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func (t *chTun) Close() error {
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t.Write(nil, -1)
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return nil
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}
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func assertNil(t *testing.T, err error) {
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@ -66,3 +224,15 @@ func assertEqual(t *testing.T, a, b []byte) {
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t.Fatal(a, "!=", b)
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}
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}
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func randDevice(t *testing.T) *Device {
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sk, err := newPrivateKey()
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if err != nil {
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t.Fatal(err)
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}
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tun := newDummyTUN("dummy")
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logger := NewLogger(LogLevelError, "")
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device := NewDevice(tun, logger)
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device.SetPrivateKey(sk)
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return device
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}
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