diff --git a/disco/disco.go b/disco/disco.go index b4d0ea2a1..f29d3342f 100644 --- a/disco/disco.go +++ b/disco/disco.go @@ -70,7 +70,7 @@ func Parse(p []byte) (Message, error) { case TypePong: return parsePong(ver, p) case TypeCallMeMaybe: - return CallMeMaybe{}, nil + return parseCallMeMaybe(ver, p) default: return nil, fmt.Errorf("unknown message type 0x%02x", byte(t)) } @@ -122,13 +122,49 @@ func parsePing(ver uint8, p []byte) (m *Ping, err error) { // // The recipient may choose to not open a path back, if it's already // happy with its path. But usually it will. -type CallMeMaybe struct{} +type CallMeMaybe struct { + // MyNumber is what the peer believes its endpoints are. + // Tailscale clients before 1.4 did not populate this + // so these values should merely augment whetever the control + // server sends. But because the client could've been idle + // before it reached out to us, the control plane might + // have stale info and these endpoints in CallMeMaybe + // might contain the just-obtained-milliseconds-ago + // STUN endpoint. + MyNumber []netaddr.IPPort +} + +const epLength = 16 + 2 // 16 byte IP address + 2 byte port -func (CallMeMaybe) AppendMarshal(b []byte) []byte { - ret, _ := appendMsgHeader(b, TypeCallMeMaybe, v0, 0) +func (m *CallMeMaybe) AppendMarshal(b []byte) []byte { + ret, p := appendMsgHeader(b, TypeCallMeMaybe, v0, epLength*len(m.MyNumber)) + for _, ipp := range m.MyNumber { + a := ipp.IP.As16() + copy(p[:], a[:]) + binary.BigEndian.PutUint16(p[16:], ipp.Port) + p = p[epLength:] + } return ret } +func parseCallMeMaybe(ver uint8, p []byte) (m *CallMeMaybe, err error) { + m = new(CallMeMaybe) + if len(p)%epLength != 0 || ver != 0 || len(p) == 0 { + return m, nil + } + m.MyNumber = make([]netaddr.IPPort, 0, len(p)/epLength) + for len(p) > 0 { + var a [16]byte + copy(a[:], p) + m.MyNumber = append(m.MyNumber, netaddr.IPPort{ + IP: netaddr.IPFrom16(a), + Port: binary.BigEndian.Uint16(p[16:18]), + }) + p = p[epLength:] + } + return m, nil +} + // Pong is a response a Ping. // // It includes the sender's source IP + port, so it's effectively a @@ -171,7 +207,7 @@ func MessageSummary(m Message) string { return fmt.Sprintf("ping tx=%x", m.TxID[:6]) case *Pong: return fmt.Sprintf("pong tx=%x", m.TxID[:6]) - case CallMeMaybe: + case *CallMeMaybe: return "call-me-maybe" default: return fmt.Sprintf("%#v", m) diff --git a/disco/disco_test.go b/disco/disco_test.go index 723b07ab6..9b16e62ba 100644 --- a/disco/disco_test.go +++ b/disco/disco_test.go @@ -44,9 +44,19 @@ func TestMarshalAndParse(t *testing.T) { }, { name: "call_me_maybe", - m: CallMeMaybe{}, + m: &CallMeMaybe{}, want: "03 00", }, + { + name: "call_me_maybe_endpoints", + m: &CallMeMaybe{ + MyNumber: []netaddr.IPPort{ + netaddr.MustParseIPPort("1.2.3.4:567"), + netaddr.MustParseIPPort("[2001::3456]:789"), + }, + }, + want: "03 00 00 00 00 00 00 00 00 00 00 00 ff ff 01 02 03 04 02 37 20 01 00 00 00 00 00 00 00 00 00 00 00 00 34 56 03 15", + }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { diff --git a/wgengine/magicsock/magicsock.go b/wgengine/magicsock/magicsock.go index 223b51d8c..674a37d21 100644 --- a/wgengine/magicsock/magicsock.go +++ b/wgengine/magicsock/magicsock.go @@ -1843,7 +1843,7 @@ func (c *Conn) handleDiscoMessage(msg []byte, src netaddr.IPPort) bool { return true } de.handlePongConnLocked(dm, src) - case disco.CallMeMaybe: + case *disco.CallMeMaybe: if src.IP != derpMagicIPAddr { // CallMeMaybe messages should only come via DERP. c.logf("[unexpected] CallMeMaybe packets should only come via DERP") @@ -3241,7 +3241,7 @@ func (de *discoEndpoint) sendPingsLocked(now time.Time, sendCallMeMaybe bool) { // so our firewall ports are probably open and now would be a good time // for them to connect. time.AfterFunc(5*time.Millisecond, func() { - de.sendDiscoMessage(derpAddr, disco.CallMeMaybe{}, discoLog) + de.sendDiscoMessage(derpAddr, &disco.CallMeMaybe{}, discoLog) }) } }