package hscontrol
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"html/template"
"net/http"
"strconv"
"strings"
"time"
"github.com/gorilla/mux"
"github.com/rs/zerolog/log"
"tailscale.com/tailcfg"
"tailscale.com/types/key"
)
const (
// The CapabilityVersion is used by Tailscale clients to indicate
// their codebase version. Tailscale clients can communicate over TS2021
// from CapabilityVersion 28, but we only have good support for it
// since https://github.com/tailscale/tailscale/pull/4323 (Noise in any HTTPS port).
//
// Related to this change, there is https://github.com/tailscale/tailscale/pull/5379,
// where CapabilityVersion 39 is introduced to indicate #4323 was merged.
//
// See also https://github.com/tailscale/tailscale/blob/main/tailcfg/tailcfg.go
NoiseCapabilityVersion = 39
// TODO(juan): remove this once https://github.com/juanfont/headscale/issues/727 is fixed.
registrationHoldoff = time.Second * 5
reservedResponseHeaderSize = 4
)
var ErrRegisterMethodCLIDoesNotSupportExpire = errors.New(
"machines registered with CLI does not support expire",
)
var ErrNoCapabilityVersion = errors.New("no capability version set")
func parseCabailityVersion(req *http.Request) (tailcfg.CapabilityVersion, error) {
clientCapabilityStr := req.URL.Query().Get("v")
if clientCapabilityStr == "" {
return 0, ErrNoCapabilityVersion
}
clientCapabilityVersion, err := strconv.Atoi(clientCapabilityStr)
if err != nil {
return 0, fmt.Errorf("failed to parse capability version: %w", err)
}
return tailcfg.CapabilityVersion(clientCapabilityVersion), nil
}
// KeyHandler provides the Headscale pub key
// Listens in /key.
func (h *Headscale) KeyHandler(
writer http.ResponseWriter,
req *http.Request,
) {
// New Tailscale clients send a 'v' parameter to indicate the CurrentCapabilityVersion
capVer, err := parseCabailityVersion(req)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("could not get capability version")
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
writer.WriteHeader(http.StatusInternalServerError)
return
}
log.Debug().
Str("handler", "/key").
Int("cap_ver", int(capVer)).
Msg("New noise client")
// TS2021 (Tailscale v2 protocol) requires to have a different key
if capVer >= NoiseCapabilityVersion {
resp := tailcfg.OverTLSPublicKeyResponse{
PublicKey: h.noisePrivateKey.Public(),
}
writer.Header().Set("Content-Type", "application/json")
writer.WriteHeader(http.StatusOK)
err = json.NewEncoder(writer).Encode(resp)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
return
}
}
func (h *Headscale) HealthHandler(
writer http.ResponseWriter,
req *http.Request,
) {
respond := func(err error) {
writer.Header().Set("Content-Type", "application/health+json; charset=utf-8")
res := struct {
Status string `json:"status"`
}{
Status: "pass",
}
if err != nil {
writer.WriteHeader(http.StatusInternalServerError)
log.Error().Caller().Err(err).Msg("health check failed")
res.Status = "fail"
}
buf, err := json.Marshal(res)
if err != nil {
log.Error().Caller().Err(err).Msg("marshal failed")
}
_, err = writer.Write(buf)
if err != nil {
log.Error().Caller().Err(err).Msg("write failed")
}
}
if err := h.db.PingDB(req.Context()); err != nil {
respond(err)
return
}
respond(nil)
}
type registerWebAPITemplateConfig struct {
Key string
}
var registerWebAPITemplate = template.Must(
template.New("registerweb").Parse(`
Registration - Headscale
headscale
Machine registration
Run the command below in the headscale server to add this machine to your network:
headscale nodes register --user USERNAME --key {{.Key}}
`))
type AuthProviderWeb struct {
serverURL string
}
func NewAuthProviderWeb(serverURL string) *AuthProviderWeb {
return &AuthProviderWeb{
serverURL: serverURL,
}
}
func (a *AuthProviderWeb) AuthURL(mKey key.MachinePublic) string {
return fmt.Sprintf(
"%s/register/%s",
strings.TrimSuffix(a.serverURL, "/"),
mKey.String())
}
// RegisterWebAPI shows a simple message in the browser to point to the CLI
// Listens in /register/:nkey.
//
// This is not part of the Tailscale control API, as we could send whatever URL
// in the RegisterResponse.AuthURL field.
func (a *AuthProviderWeb) RegisterHandler(
writer http.ResponseWriter,
req *http.Request,
) {
vars := mux.Vars(req)
machineKeyStr := vars["mkey"]
// We need to make sure we dont open for XSS style injections, if the parameter that
// is passed as a key is not parsable/validated as a NodePublic key, then fail to render
// the template and log an error.
var machineKey key.MachinePublic
err := machineKey.UnmarshalText(
[]byte(machineKeyStr),
)
if err != nil {
log.Warn().Err(err).Msg("Failed to parse incoming machinekey")
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
writer.WriteHeader(http.StatusBadRequest)
_, err := writer.Write([]byte("Wrong params"))
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
return
}
var content bytes.Buffer
if err := registerWebAPITemplate.Execute(&content, registerWebAPITemplateConfig{
Key: machineKey.String(),
}); err != nil {
log.Error().
Str("func", "RegisterWebAPI").
Err(err).
Msg("Could not render register web API template")
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
writer.WriteHeader(http.StatusInternalServerError)
_, err = writer.Write([]byte("Could not render register web API template"))
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
return
}
writer.Header().Set("Content-Type", "text/html; charset=utf-8")
writer.WriteHeader(http.StatusOK)
_, err = writer.Write(content.Bytes())
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
}