mirror of
https://github.com/tailscale/tailscale.git
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move more to network, hardcode less
Change-Id: If1c773153f7f3fa7ea483d1b7231193ab093278a Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
parent
87f777d21b
commit
013ea64e94
@ -53,11 +53,12 @@ func main() {
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// Hard-coded world shape for me.
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net1 := &network{
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s: s,
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mac: MAC{0x52, 0x54, 0x00, 0x01, 0x01, 0x01},
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wanIP: netip.MustParseAddr("2.1.1.1"),
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lanIP: netip.MustParsePrefix("192.168.2.1/24"),
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}
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s.nodes[client1mac] = &node{
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s.nodes[MAC{0x5a, 0x94, 0xef, 0xe4, 0x0c, 0xee}] = &node{
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net: net1,
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lanIP: netip.MustParseAddr("192.168.2.102"),
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}
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@ -96,6 +97,11 @@ func (s *Server) checkWorld() error {
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if n.net.nodesByIP == nil {
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n.net.nodesByIP = map[netip.Addr]*node{}
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}
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if n.net.ns == nil {
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if err := n.net.initStack(); err != nil {
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return fmt.Errorf("newServer: initStack: %v", err)
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}
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}
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if _, ok := n.net.nodesByIP[n.lanIP]; ok {
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return fmt.Errorf("node %v has duplicate LAN IP %v", mac, n.lanIP)
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}
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@ -104,8 +110,8 @@ func (s *Server) checkWorld() error {
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return nil
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}
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func (s *Server) initStack() error {
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s.ns = stack.New(stack.Options{
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func (n *network) initStack() error {
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n.ns = stack.New(stack.Options{
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NetworkProtocols: []stack.NetworkProtocolFactory{
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ipv4.NewProtocol,
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arp.NewProtocol,
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@ -116,20 +122,20 @@ func (s *Server) initStack() error {
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},
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})
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sackEnabledOpt := tcpip.TCPSACKEnabled(true) // TCP SACK is disabled by default
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tcpipErr := s.ns.SetTransportProtocolOption(tcp.ProtocolNumber, &sackEnabledOpt)
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tcpipErr := n.ns.SetTransportProtocolOption(tcp.ProtocolNumber, &sackEnabledOpt)
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if tcpipErr != nil {
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return fmt.Errorf("SetTransportProtocolOption SACK: %v", tcpipErr)
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}
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s.linkEP = channel.New(512, 1500, tcpip.LinkAddress(gwMACTOREMOVE))
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if tcpipProblem := s.ns.CreateNIC(nicID, s.linkEP); tcpipProblem != nil {
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n.linkEP = channel.New(512, 1500, tcpip.LinkAddress(n.mac.HWAddr()))
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if tcpipProblem := n.ns.CreateNIC(nicID, n.linkEP); tcpipProblem != nil {
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return fmt.Errorf("CreateNIC: %v", tcpipProblem)
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}
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s.ns.SetPromiscuousMode(nicID, true)
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s.ns.SetSpoofing(nicID, true)
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n.ns.SetPromiscuousMode(nicID, true)
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n.ns.SetSpoofing(nicID, true)
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prefix := tcpip.AddrFrom4Slice(gwIP.AsSlice()).WithPrefix()
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prefix.PrefixLen = 24
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if tcpProb := s.ns.AddProtocolAddress(nicID, tcpip.ProtocolAddress{
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prefix := tcpip.AddrFrom4Slice(n.lanIP.Addr().AsSlice()).WithPrefix()
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prefix.PrefixLen = n.lanIP.Bits()
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if tcpProb := n.ns.AddProtocolAddress(nicID, tcpip.ProtocolAddress{
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Protocol: ipv4.ProtocolNumber,
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AddressWithPrefix: prefix,
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}, stack.AddressProperties{}); tcpProb != nil {
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@ -140,7 +146,7 @@ func (s *Server) initStack() error {
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if err != nil {
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return fmt.Errorf("could not create IPv4 subnet: %v", err)
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}
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s.ns.SetRouteTable([]tcpip.Route{
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n.ns.SetRouteTable([]tcpip.Route{
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{
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Destination: ipv4Subnet,
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NIC: nicID,
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@ -149,17 +155,17 @@ func (s *Server) initStack() error {
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const tcpReceiveBufferSize = 0 // default
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const maxInFlightConnectionAttempts = 8192
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tcpFwd := tcp.NewForwarder(s.ns, tcpReceiveBufferSize, maxInFlightConnectionAttempts, s.acceptTCP)
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s.ns.SetTransportProtocolHandler(tcp.ProtocolNumber, func(tei stack.TransportEndpointID, pb *stack.PacketBuffer) (handled bool) {
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tcpFwd := tcp.NewForwarder(n.ns, tcpReceiveBufferSize, maxInFlightConnectionAttempts, n.acceptTCP)
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n.ns.SetTransportProtocolHandler(tcp.ProtocolNumber, func(tei stack.TransportEndpointID, pb *stack.PacketBuffer) (handled bool) {
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log.Printf("TCP packet: %+v", tei)
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return tcpFwd.HandlePacket(tei, pb)
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})
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go func() {
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for {
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pkt := s.linkEP.ReadContext(s.shutdownCtx)
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pkt := n.linkEP.ReadContext(n.s.shutdownCtx)
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if pkt.IsNil() {
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if s.shutdownCtx.Err() != nil {
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if n.s.shutdownCtx.Err() != nil {
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// Return without logging.
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return
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}
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@ -168,14 +174,20 @@ func (s *Server) initStack() error {
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}
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ipRaw := pkt.ToView().AsSlice()
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log.Printf("Read packet from linkEP: % 02x", ipRaw)
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goPkt := gopacket.NewPacket(
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ipRaw,
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layers.LayerTypeIPv4, gopacket.Lazy)
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layerV4 := goPkt.Layer(layers.LayerTypeIPv4).(*layers.IPv4)
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dstIP, _ := netip.AddrFromSlice(layerV4.DstIP)
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node, ok := n.nodesByIP[dstIP]
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if !ok {
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log.Printf("no MAC for dest IP %v", dstIP)
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continue
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}
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eth := &layers.Ethernet{
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SrcMAC: gwMACTOREMOVE,
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DstMAC: client1mac.HWAddr(),
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SrcMAC: n.mac.HWAddr(),
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DstMAC: node.mac.HWAddr(),
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EthernetType: layers.EthernetTypeIPv4,
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}
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buffer := gopacket.NewSerializeBuffer()
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@ -201,11 +213,11 @@ func (s *Server) initStack() error {
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log.Printf("Serialize error: %v", err)
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continue
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}
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if writeFunc, ok := s.writeFunc.Load(client1mac); ok {
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if writeFunc, ok := n.writeFunc.Load(node.mac); ok {
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writeFunc(buffer.Bytes())
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log.Printf("wrote packet to client: % 02x", buffer.Bytes())
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} else {
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log.Printf("No writeFunc for %v", client1mac)
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log.Printf("No writeFunc for %v", node.mac)
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}
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}
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}()
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@ -228,7 +240,7 @@ func stringifyTEI(tei stack.TransportEndpointID) string {
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return fmt.Sprintf("%s -> %s", remoteHostPort, localHostPort)
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}
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func (s *Server) acceptTCP(r *tcp.ForwarderRequest) {
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func (n *network) acceptTCP(r *tcp.ForwarderRequest) {
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reqDetails := r.ID()
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log.Printf("AcceptTCP: %v", stringifyTEI(reqDetails))
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@ -275,17 +287,10 @@ func (s *Server) acceptTCP(r *tcp.ForwarderRequest) {
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}
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var (
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// TODO: remove this and run a netstack per *network instead.
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gwMACTOREMOVE = net.HardwareAddr{0x52, 0x54, 0x00, 0x01, 0x01, 0x01}
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fakeDNSIP = netip.AddrFrom4([4]byte{4, 11, 4, 11})
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fakeControlplaneIP = netip.AddrFrom4([4]byte{52, 52, 0, 1})
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)
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var gwIP = netip.AddrFrom4([4]byte{192, 168, 1, 1})
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var client1mac = MAC{0x5a, 0x94, 0xef, 0xe4, 0x0c, 0xee}
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type MAC [6]byte
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func macOf(hwa net.HardwareAddr) (_ MAC, ok bool) {
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@ -304,12 +309,27 @@ func (m MAC) String() string {
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}
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type network struct {
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s *Server
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mac MAC
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doesNAT bool
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wanIP netip.Addr
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lanIP netip.Prefix // with host bits set (e.g. 192.168.2.1/24)
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nodesByIP map[netip.Addr]*node
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ns *stack.Stack
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linkEP *channel.Endpoint
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// writeFunc is a map of MAC -> func to write to that MAC.
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// It contains entries for connected nodes only.
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writeFunc syncs.Map[MAC, func([]byte)] // MAC -> func to write to that MAC
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}
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func (n *network) registerWriter(mac MAC, f func([]byte)) {
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if f != nil {
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n.writeFunc.Store(mac, f)
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} else {
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n.writeFunc.Delete(mac)
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}
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}
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func (n *network) MACOfIP(ip netip.Addr) (_ MAC, ok bool) {
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@ -333,11 +353,6 @@ type Server struct {
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shutdownCancel context.CancelFunc
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nodes map[MAC]*node
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writeFunc syncs.Map[MAC, func([]byte)] // MAC -> func to write to that MAC
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ns *stack.Stack
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linkEP *channel.Endpoint
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}
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func newServer() (*Server, error) {
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@ -347,9 +362,6 @@ func newServer() (*Server, error) {
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shutdownCancel: cancel,
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nodes: map[MAC]*node{},
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}
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if err := s.initStack(); err != nil {
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return nil, fmt.Errorf("newServer: initStack: %v", err)
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}
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return s, nil
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}
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@ -371,7 +383,7 @@ func (s *Server) IPv4ForDNS(qname string) (netip.Addr, bool) {
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}
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func (s *Server) serveConn(uc net.Conn) {
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log.Printf("Got conn")
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log.Printf("Got conn %p", uc)
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defer uc.Close()
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bw := bufio.NewWriterSize(uc, 2<<10)
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@ -395,9 +407,10 @@ func (s *Server) serveConn(uc net.Conn) {
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log.Printf("Flush: %v", err)
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}
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}
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s.writeFunc.Store(client1mac, writePkt)
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buf := make([]byte, 16<<10)
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var srcNode *node
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var netw *network // non-nil after first packet
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for {
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if _, err := io.ReadFull(uc, buf[:4]); err != nil {
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log.Printf("ReadFull header: %v", err)
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@ -416,9 +429,26 @@ func (s *Server) serveConn(uc net.Conn) {
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if !ok {
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continue
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}
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srcMAC := MAC(ll.SrcMAC)
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if srcNode == nil {
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srcNode, ok = s.nodes[srcMAC]
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if !ok {
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log.Printf("[conn %p] ignoring frame from unknown MAC %v", uc, srcMAC)
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continue
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}
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log.Printf("[conn %p] MAC %v is node %v", uc, srcMAC, srcNode.lanIP)
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netw = srcNode.net
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netw.registerWriter(srcMAC, writePkt)
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defer netw.registerWriter(srcMAC, nil)
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} else {
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if srcMAC != srcNode.mac {
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log.Printf("[conn %p] ignoring frame from MAC %v, expected %v", uc, srcMAC, srcNode.mac)
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continue
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}
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}
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if ll.EthernetType == layers.EthernetTypeARP {
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res, err := s.createARPResponse(packet)
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res, err := netw.createARPResponse(packet)
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if err != nil {
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log.Printf("createARPResponse: %v", err)
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} else {
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@ -478,7 +508,7 @@ func (s *Server) serveConn(uc net.Conn) {
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packetBuf := stack.NewPacketBuffer(stack.PacketBufferOptions{
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Payload: buffer.MakeWithData(pktCopy),
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})
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s.linkEP.InjectInbound(header.IPv4ProtocolNumber, packetBuf)
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netw.linkEP.InjectInbound(header.IPv4ProtocolNumber, packetBuf)
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// var list stack.PacketBufferList
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// list.PushBack(packetBuf)
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@ -679,7 +709,7 @@ func (s *Server) createSTUNResponse(pkt gopacket.Packet) ([]byte, error) {
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log.Printf("invalid STUN request: %v", err)
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return nil, nil
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}
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stunRes := stun.Response(txid, netip.AddrPortFrom(gwIP, 31234))
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stunRes := stun.Response(txid, netip.AddrPortFrom(netip.MustParseAddr("1.2.3.4"), 12345))
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eth2 := &layers.Ethernet{
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SrcMAC: ethLayer.DstMAC,
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@ -786,30 +816,24 @@ func (s *Server) createDNSResponse(pkt gopacket.Packet) ([]byte, error) {
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return nil, err
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}
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const debugDNS = false
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if debugDNS {
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if len(response.Answers) > 0 {
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back := gopacket.NewPacket(buffer.Bytes(), layers.LayerTypeEthernet, gopacket.Lazy)
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log.Printf("Generated: %v", back)
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} else {
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log.Printf("made empty response for %q", names)
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}
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}
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return buffer.Bytes(), nil
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}
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func (s *Server) createARPResponse(pkt gopacket.Packet) ([]byte, error) {
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func (n *network) createARPResponse(pkt gopacket.Packet) ([]byte, error) {
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ethLayer, ok := pkt.Layer(layers.LayerTypeEthernet).(*layers.Ethernet)
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if !ok {
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return nil, nil
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}
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srcMAC, ok := macOf(ethLayer.SrcMAC)
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if !ok {
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return nil, nil
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}
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node, ok := s.nodes[srcMAC]
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if !ok {
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return nil, nil
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}
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arpLayer, ok := pkt.Layer(layers.LayerTypeARP).(*layers.ARP)
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if !ok ||
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arpLayer.Operation != layers.ARPRequest ||
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@ -822,7 +846,7 @@ func (s *Server) createARPResponse(pkt gopacket.Packet) ([]byte, error) {
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}
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wantIP := netip.AddrFrom4([4]byte(arpLayer.DstProtAddress))
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foundMAC, ok := node.net.MACOfIP(wantIP)
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foundMAC, ok := n.MACOfIP(wantIP)
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if !ok {
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return nil, nil
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}
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