mirror of
https://github.com/juanfont/headscale.git
synced 2024-12-05 13:13:05 +00:00
1e61084898
* handle control protocol through websocket The necessary behaviour is already in place, but the wasm build only issued GETs, and the handler was not invoked. * get DERP-over-websocket working for wasm clients * Prepare for testing builtin websocket-over-DERP Still needs some way to assert that clients are connected through websockets, rather than the TCP hijacking version of DERP. * integration tests: properly differentiate between DERP transports * do not touch unrelated code * linter fixes * integration testing: unexport common implementation of derp server scenario * fixup! integration testing: unexport common implementation of derp server scenario * dockertestutil/logs: remove unhelpful comment * update changelog --------- Co-authored-by: Csaba Sarkadi <sarkadicsa@tutanota.de>
362 lines
9.7 KiB
Go
362 lines
9.7 KiB
Go
package server
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import (
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"bufio"
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"context"
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"encoding/json"
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"fmt"
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"net"
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"net/http"
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"net/netip"
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"net/url"
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"strconv"
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"strings"
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"time"
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"github.com/coder/websocket"
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"github.com/juanfont/headscale/hscontrol/types"
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"github.com/juanfont/headscale/hscontrol/util"
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"github.com/rs/zerolog/log"
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"tailscale.com/derp"
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"tailscale.com/net/stun"
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"tailscale.com/net/wsconn"
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"tailscale.com/tailcfg"
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"tailscale.com/types/key"
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)
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// fastStartHeader is the header (with value "1") that signals to the HTTP
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// server that the DERP HTTP client does not want the HTTP 101 response
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// headers and it will begin writing & reading the DERP protocol immediately
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// following its HTTP request.
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const fastStartHeader = "Derp-Fast-Start"
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type DERPServer struct {
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serverURL string
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key key.NodePrivate
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cfg *types.DERPConfig
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tailscaleDERP *derp.Server
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}
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func NewDERPServer(
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serverURL string,
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derpKey key.NodePrivate,
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cfg *types.DERPConfig,
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) (*DERPServer, error) {
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log.Trace().Caller().Msg("Creating new embedded DERP server")
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server := derp.NewServer(derpKey, util.TSLogfWrapper()) // nolint // zerolinter complains
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return &DERPServer{
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serverURL: serverURL,
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key: derpKey,
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cfg: cfg,
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tailscaleDERP: server,
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}, nil
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}
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func (d *DERPServer) GenerateRegion() (tailcfg.DERPRegion, error) {
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serverURL, err := url.Parse(d.serverURL)
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if err != nil {
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return tailcfg.DERPRegion{}, err
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}
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var host string
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var port int
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host, portStr, err := net.SplitHostPort(serverURL.Host)
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if err != nil {
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if serverURL.Scheme == "https" {
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host = serverURL.Host
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port = 443
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} else {
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host = serverURL.Host
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port = 80
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}
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} else {
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port, err = strconv.Atoi(portStr)
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if err != nil {
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return tailcfg.DERPRegion{}, err
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}
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}
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localDERPregion := tailcfg.DERPRegion{
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RegionID: d.cfg.ServerRegionID,
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RegionCode: d.cfg.ServerRegionCode,
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RegionName: d.cfg.ServerRegionName,
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Avoid: false,
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Nodes: []*tailcfg.DERPNode{
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{
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Name: fmt.Sprintf("%d", d.cfg.ServerRegionID),
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RegionID: d.cfg.ServerRegionID,
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HostName: host,
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DERPPort: port,
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IPv4: d.cfg.IPv4,
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IPv6: d.cfg.IPv6,
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},
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},
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}
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_, portSTUNStr, err := net.SplitHostPort(d.cfg.STUNAddr)
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if err != nil {
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return tailcfg.DERPRegion{}, err
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}
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portSTUN, err := strconv.Atoi(portSTUNStr)
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if err != nil {
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return tailcfg.DERPRegion{}, err
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}
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localDERPregion.Nodes[0].STUNPort = portSTUN
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log.Info().Caller().Msgf("DERP region: %+v", localDERPregion)
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log.Info().Caller().Msgf("DERP Nodes[0]: %+v", localDERPregion.Nodes[0])
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return localDERPregion, nil
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}
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func (d *DERPServer) DERPHandler(
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writer http.ResponseWriter,
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req *http.Request,
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) {
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log.Trace().Caller().Msgf("/derp request from %v", req.RemoteAddr)
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upgrade := strings.ToLower(req.Header.Get("Upgrade"))
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if upgrade != "websocket" && upgrade != "derp" {
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if upgrade != "" {
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log.Warn().
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Caller().
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Msg("No Upgrade header in DERP server request. If headscale is behind a reverse proxy, make sure it is configured to pass WebSockets through.")
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}
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writer.Header().Set("Content-Type", "text/plain")
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writer.WriteHeader(http.StatusUpgradeRequired)
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_, err := writer.Write([]byte("DERP requires connection upgrade"))
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if err != nil {
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log.Error().
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Caller().
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Err(err).
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Msg("Failed to write response")
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}
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return
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}
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if strings.Contains(req.Header.Get("Sec-Websocket-Protocol"), "derp") {
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d.serveWebsocket(writer, req)
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} else {
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d.servePlain(writer, req)
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}
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}
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func (d *DERPServer) serveWebsocket(writer http.ResponseWriter, req *http.Request) {
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websocketConn, err := websocket.Accept(writer, req, &websocket.AcceptOptions{
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Subprotocols: []string{"derp"},
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OriginPatterns: []string{"*"},
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// Disable compression because DERP transmits WireGuard messages that
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// are not compressible.
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// Additionally, Safari has a broken implementation of compression
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// (see https://github.com/nhooyr/websocket/issues/218) that makes
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// enabling it actively harmful.
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CompressionMode: websocket.CompressionDisabled,
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})
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if err != nil {
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log.Error().
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Caller().
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Err(err).
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Msg("Failed to upgrade websocket request")
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writer.Header().Set("Content-Type", "text/plain")
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writer.WriteHeader(http.StatusInternalServerError)
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_, err = writer.Write([]byte("Failed to upgrade websocket request"))
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if err != nil {
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log.Error().
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Caller().
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Err(err).
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Msg("Failed to write response")
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}
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return
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}
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defer websocketConn.Close(websocket.StatusInternalError, "closing")
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if websocketConn.Subprotocol() != "derp" {
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websocketConn.Close(websocket.StatusPolicyViolation, "client must speak the derp subprotocol")
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return
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}
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wc := wsconn.NetConn(req.Context(), websocketConn, websocket.MessageBinary, req.RemoteAddr)
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brw := bufio.NewReadWriter(bufio.NewReader(wc), bufio.NewWriter(wc))
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d.tailscaleDERP.Accept(req.Context(), wc, brw, req.RemoteAddr)
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}
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func (d *DERPServer) servePlain(writer http.ResponseWriter, req *http.Request) {
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fastStart := req.Header.Get(fastStartHeader) == "1"
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hijacker, ok := writer.(http.Hijacker)
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if !ok {
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log.Error().Caller().Msg("DERP requires Hijacker interface from Gin")
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writer.Header().Set("Content-Type", "text/plain")
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writer.WriteHeader(http.StatusInternalServerError)
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_, err := writer.Write([]byte("HTTP does not support general TCP support"))
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if err != nil {
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log.Error().
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Caller().
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Err(err).
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Msg("Failed to write response")
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}
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return
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}
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netConn, conn, err := hijacker.Hijack()
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if err != nil {
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log.Error().Caller().Err(err).Msgf("Hijack failed")
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writer.Header().Set("Content-Type", "text/plain")
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writer.WriteHeader(http.StatusInternalServerError)
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_, err = writer.Write([]byte("HTTP does not support general TCP support"))
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if err != nil {
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log.Error().
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Caller().
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Err(err).
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Msg("Failed to write response")
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}
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return
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}
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log.Trace().Caller().Msgf("Hijacked connection from %v", req.RemoteAddr)
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if !fastStart {
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pubKey := d.key.Public()
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pubKeyStr, _ := pubKey.MarshalText() //nolint
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fmt.Fprintf(conn, "HTTP/1.1 101 Switching Protocols\r\n"+
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"Upgrade: DERP\r\n"+
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"Connection: Upgrade\r\n"+
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"Derp-Version: %v\r\n"+
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"Derp-Public-Key: %s\r\n\r\n",
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derp.ProtocolVersion,
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string(pubKeyStr))
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}
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d.tailscaleDERP.Accept(req.Context(), netConn, conn, netConn.RemoteAddr().String())
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}
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// DERPProbeHandler is the endpoint that js/wasm clients hit to measure
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// DERP latency, since they can't do UDP STUN queries.
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func DERPProbeHandler(
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writer http.ResponseWriter,
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req *http.Request,
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) {
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switch req.Method {
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case http.MethodHead, http.MethodGet:
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writer.Header().Set("Access-Control-Allow-Origin", "*")
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writer.WriteHeader(http.StatusOK)
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default:
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writer.WriteHeader(http.StatusMethodNotAllowed)
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_, err := writer.Write([]byte("bogus probe method"))
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if err != nil {
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log.Error().
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Caller().
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Err(err).
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Msg("Failed to write response")
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}
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}
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}
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// DERPBootstrapDNSHandler implements the /bootstrap-dns endpoint
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// Described in https://github.com/tailscale/tailscale/issues/1405,
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// this endpoint provides a way to help a client when it fails to start up
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// because its DNS are broken.
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// The initial implementation is here https://github.com/tailscale/tailscale/pull/1406
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// They have a cache, but not clear if that is really necessary at Headscale, uh, scale.
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// An example implementation is found here https://derp.tailscale.com/bootstrap-dns
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// Coordination server is included automatically, since local DERP is using the same DNS Name in d.serverURL.
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func DERPBootstrapDNSHandler(
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derpMap *tailcfg.DERPMap,
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) func(http.ResponseWriter, *http.Request) {
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return func(
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writer http.ResponseWriter,
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req *http.Request,
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) {
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dnsEntries := make(map[string][]net.IP)
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resolvCtx, cancel := context.WithTimeout(req.Context(), time.Minute)
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defer cancel()
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var resolver net.Resolver
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for _, region := range derpMap.Regions {
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for _, node := range region.Nodes { // we don't care if we override some nodes
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addrs, err := resolver.LookupIP(resolvCtx, "ip", node.HostName)
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if err != nil {
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log.Trace().
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Caller().
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Err(err).
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Msgf("bootstrap DNS lookup failed %q", node.HostName)
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continue
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}
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dnsEntries[node.HostName] = addrs
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}
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}
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writer.Header().Set("Content-Type", "application/json")
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writer.WriteHeader(http.StatusOK)
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err := json.NewEncoder(writer).Encode(dnsEntries)
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if err != nil {
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log.Error().
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Caller().
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Err(err).
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Msg("Failed to write response")
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}
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}
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}
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// ServeSTUN starts a STUN server on the configured addr.
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func (d *DERPServer) ServeSTUN() {
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packetConn, err := net.ListenPacket("udp", d.cfg.STUNAddr)
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if err != nil {
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log.Fatal().Msgf("failed to open STUN listener: %v", err)
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}
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log.Info().Msgf("STUN server started at %s", packetConn.LocalAddr())
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udpConn, ok := packetConn.(*net.UDPConn)
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if !ok {
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log.Fatal().Msg("STUN listener is not a UDP listener")
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}
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serverSTUNListener(context.Background(), udpConn)
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}
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func serverSTUNListener(ctx context.Context, packetConn *net.UDPConn) {
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var buf [64 << 10]byte
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var (
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bytesRead int
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udpAddr *net.UDPAddr
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err error
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)
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for {
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bytesRead, udpAddr, err = packetConn.ReadFromUDP(buf[:])
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if err != nil {
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if ctx.Err() != nil {
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return
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}
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log.Error().Caller().Err(err).Msgf("STUN ReadFrom")
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time.Sleep(time.Second)
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continue
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}
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log.Trace().Caller().Msgf("STUN request from %v", udpAddr)
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pkt := buf[:bytesRead]
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if !stun.Is(pkt) {
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log.Trace().Caller().Msgf("UDP packet is not STUN")
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continue
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}
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txid, err := stun.ParseBindingRequest(pkt)
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if err != nil {
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log.Trace().Caller().Err(err).Msgf("STUN parse error")
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continue
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}
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addr, _ := netip.AddrFromSlice(udpAddr.IP)
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res := stun.Response(txid, netip.AddrPortFrom(addr, uint16(udpAddr.Port)))
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_, err = packetConn.WriteTo(res, udpAddr)
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if err != nil {
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log.Trace().Caller().Err(err).Msgf("Issue writing to UDP")
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continue
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}
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}
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}
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