package headscale
import (
"encoding/binary"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"strings"
"time"
"github.com/gin-gonic/gin"
"github.com/klauspost/compress/zstd"
"github.com/rs/zerolog/log"
"gorm.io/gorm"
"tailscale.com/tailcfg"
"tailscale.com/types/wgkey"
)
const (
reservedResponseHeaderSize = 4
RegisterMethodAuthKey = "authKey"
RegisterMethodOIDC = "oidc"
RegisterMethodCLI = "cli"
)
// KeyHandler provides the Headscale pub key
// Listens in /key.
func (h *Headscale) KeyHandler(ctx *gin.Context) {
ctx.Data(
http.StatusOK,
"text/plain; charset=utf-8",
[]byte(h.publicKey.HexString()),
)
}
// RegisterWebAPI shows a simple message in the browser to point to the CLI
// Listens in /register.
func (h *Headscale) RegisterWebAPI(ctx *gin.Context) {
machineKeyStr := ctx.Query("key")
if machineKeyStr == "" {
ctx.String(http.StatusBadRequest, "Wrong params")
return
}
ctx.Data(http.StatusOK, "text/html; charset=utf-8", []byte(fmt.Sprintf(`
headscale
Run the command below in the headscale server to add this machine to your network:
headscale -n NAMESPACE nodes register --key %s
`, machineKeyStr)))
}
// RegistrationHandler handles the actual registration process of a machine
// Endpoint /machine/:id.
func (h *Headscale) RegistrationHandler(ctx *gin.Context) {
body, _ := io.ReadAll(ctx.Request.Body)
machineKeyStr := ctx.Param("id")
machineKey, err := wgkey.ParseHex(machineKeyStr)
if err != nil {
log.Error().
Str("handler", "Registration").
Err(err).
Msg("Cannot parse machine key")
machineRegistrations.WithLabelValues("unknown", "web", "error", "unknown").Inc()
ctx.String(http.StatusInternalServerError, "Sad!")
return
}
req := tailcfg.RegisterRequest{}
err = decode(body, &req, &machineKey, h.privateKey)
if err != nil {
log.Error().
Str("handler", "Registration").
Err(err).
Msg("Cannot decode message")
machineRegistrations.WithLabelValues("unknown", "web", "error", "unknown").Inc()
ctx.String(http.StatusInternalServerError, "Very sad!")
return
}
now := time.Now().UTC()
machine, err := h.GetMachineByMachineKey(machineKey.HexString())
if errors.Is(err, gorm.ErrRecordNotFound) {
log.Info().Str("machine", req.Hostinfo.Hostname).Msg("New machine")
newMachine := Machine{
Expiry: &time.Time{},
MachineKey: machineKey.HexString(),
Name: req.Hostinfo.Hostname,
}
if err := h.db.Create(&newMachine).Error; err != nil {
log.Error().
Str("handler", "Registration").
Err(err).
Msg("Could not create row")
machineRegistrations.WithLabelValues("unknown", "web", "error", machine.Namespace.Name).
Inc()
return
}
machine = &newMachine
}
if !machine.Registered && req.Auth.AuthKey != "" {
h.handleAuthKey(ctx, machineKey, req, *machine)
return
}
// We have the updated key!
if machine.NodeKey == wgkey.Key(req.NodeKey).HexString() {
// The client sends an Expiry in the past if the client is requesting to expire the key (aka logout)
// https://github.com/tailscale/tailscale/blob/main/tailcfg/tailcfg.go#L648
if !req.Expiry.IsZero() && req.Expiry.UTC().Before(now) {
h.handleMachineLogOut(ctx, machineKey, req, *machine)
return
}
// We dont care about expiry time if the method is AuthKey, as we dont set that.
if machine.Registered && machine.RegisterMethod == RegisterMethodAuthKey {
h.handleMachineValidRegistration(ctx, machineKey, *machine)
return
}
if machine.Registered && !machine.isExpired() {
h.handleMachineValidRegistration(ctx, machineKey, *machine)
return
}
h.handleMachineExpired(ctx, machineKey, req, *machine)
return
}
// The NodeKey we have matches OldNodeKey, which means this is a refresh after a key expiration
if machine.NodeKey == wgkey.Key(req.OldNodeKey).HexString() &&
!machine.isExpired() {
h.handleMachineRefreshKey(ctx, machineKey, req, *machine)
return
}
h.handleMachineRegistrationNew(ctx, machineKey, req, *machine)
}
func (h *Headscale) getMapResponse(
machineKey wgkey.Key,
req tailcfg.MapRequest,
machine *Machine,
) ([]byte, error) {
log.Trace().
Str("func", "getMapResponse").
Str("machine", req.Hostinfo.Hostname).
Msg("Creating Map response")
node, err := machine.toNode(h.cfg.BaseDomain, h.cfg.DNSConfig, true)
if err != nil {
log.Error().
Str("func", "getMapResponse").
Err(err).
Msg("Cannot convert to node")
return nil, err
}
peers, err := h.getPeers(machine)
if err != nil {
log.Error().
Str("func", "getMapResponse").
Err(err).
Msg("Cannot fetch peers")
return nil, err
}
profiles := getMapResponseUserProfiles(*machine, peers)
nodePeers, err := peers.toNodes(h.cfg.BaseDomain, h.cfg.DNSConfig, true)
if err != nil {
log.Error().
Str("func", "getMapResponse").
Err(err).
Msg("Failed to convert peers to Tailscale nodes")
return nil, err
}
dnsConfig := getMapResponseDNSConfig(
h.cfg.DNSConfig,
h.cfg.BaseDomain,
*machine,
peers,
)
resp := tailcfg.MapResponse{
KeepAlive: false,
Node: node,
Peers: nodePeers,
DNSConfig: dnsConfig,
Domain: h.cfg.BaseDomain,
PacketFilter: h.aclRules,
DERPMap: h.DERPMap,
UserProfiles: profiles,
}
log.Trace().
Str("func", "getMapResponse").
Str("machine", req.Hostinfo.Hostname).
// Interface("payload", resp).
Msgf("Generated map response: %s", tailMapResponseToString(resp))
var respBody []byte
if req.Compress == "zstd" {
src, _ := json.Marshal(resp)
encoder, _ := zstd.NewWriter(nil)
srcCompressed := encoder.EncodeAll(src, nil)
respBody, err = encodeMsg(srcCompressed, &machineKey, h.privateKey)
if err != nil {
return nil, err
}
} else {
respBody, err = encode(resp, &machineKey, h.privateKey)
if err != nil {
return nil, err
}
}
// declare the incoming size on the first 4 bytes
data := make([]byte, reservedResponseHeaderSize)
binary.LittleEndian.PutUint32(data, uint32(len(respBody)))
data = append(data, respBody...)
return data, nil
}
func (h *Headscale) getMapKeepAliveResponse(
machineKey wgkey.Key,
mapRequest tailcfg.MapRequest,
) ([]byte, error) {
mapResponse := tailcfg.MapResponse{
KeepAlive: true,
}
var respBody []byte
var err error
if mapRequest.Compress == "zstd" {
src, _ := json.Marshal(mapResponse)
encoder, _ := zstd.NewWriter(nil)
srcCompressed := encoder.EncodeAll(src, nil)
respBody, err = encodeMsg(srcCompressed, &machineKey, h.privateKey)
if err != nil {
return nil, err
}
} else {
respBody, err = encode(mapResponse, &machineKey, h.privateKey)
if err != nil {
return nil, err
}
}
data := make([]byte, reservedResponseHeaderSize)
binary.LittleEndian.PutUint32(data, uint32(len(respBody)))
data = append(data, respBody...)
return data, nil
}
func (h *Headscale) handleMachineLogOut(
ctx *gin.Context,
idKey wgkey.Key,
reqisterRequest tailcfg.RegisterRequest,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
log.Info().
Str("handler", "Registration").
Str("machine", machine.Name).
Msg("Client requested logout")
machine.Expiry = &reqisterRequest.Expiry // save the expiry so that the machine is marked as expired
h.db.Save(&machine)
resp.AuthURL = ""
resp.MachineAuthorized = false
resp.User = *machine.Namespace.toUser()
respBody, err := encode(resp, &idKey, h.privateKey)
if err != nil {
log.Error().
Str("handler", "Registration").
Err(err).
Msg("Cannot encode message")
ctx.String(http.StatusInternalServerError, "")
return
}
ctx.Data(http.StatusOK, "application/json; charset=utf-8", respBody)
}
func (h *Headscale) handleMachineValidRegistration(
ctx *gin.Context,
idKey wgkey.Key,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
// The machine registration is valid, respond with redirect to /map
log.Debug().
Str("handler", "Registration").
Str("machine", machine.Name).
Msg("Client is registered and we have the current NodeKey. All clear to /map")
resp.AuthURL = ""
resp.MachineAuthorized = true
resp.User = *machine.Namespace.toUser()
resp.Login = *machine.Namespace.toLogin()
respBody, err := encode(resp, &idKey, h.privateKey)
if err != nil {
log.Error().
Str("handler", "Registration").
Err(err).
Msg("Cannot encode message")
machineRegistrations.WithLabelValues("update", "web", "error", machine.Namespace.Name).
Inc()
ctx.String(http.StatusInternalServerError, "")
return
}
machineRegistrations.WithLabelValues("update", "web", "success", machine.Namespace.Name).
Inc()
ctx.Data(http.StatusOK, "application/json; charset=utf-8", respBody)
}
func (h *Headscale) handleMachineExpired(
ctx *gin.Context,
idKey wgkey.Key,
reqisterRequest tailcfg.RegisterRequest,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
// The client has registered before, but has expired
log.Debug().
Str("handler", "Registration").
Str("machine", machine.Name).
Msg("Machine registration has expired. Sending a authurl to register")
if h.cfg.OIDC.Issuer != "" {
resp.AuthURL = fmt.Sprintf("%s/oidc/register/%s",
strings.TrimSuffix(h.cfg.ServerURL, "/"), idKey.HexString())
} else {
resp.AuthURL = fmt.Sprintf("%s/register?key=%s",
strings.TrimSuffix(h.cfg.ServerURL, "/"), idKey.HexString())
}
// When a client connects, it may request a specific expiry time in its
// RegisterRequest (https://github.com/tailscale/tailscale/blob/main/tailcfg/tailcfg.go#L634)
// RequestedExpiry is used to store the clients requested expiry time since the authentication flow is broken
// into two steps (which cant pass arbitrary data between them easily) and needs to be
// retrieved again after the user has authenticated. After the authentication flow
// completes, RequestedExpiry is copied into Expiry.
machine.RequestedExpiry = &reqisterRequest.Expiry
h.db.Save(&machine)
respBody, err := encode(resp, &idKey, h.privateKey)
if err != nil {
log.Error().
Str("handler", "Registration").
Err(err).
Msg("Cannot encode message")
machineRegistrations.WithLabelValues("new", "web", "error", machine.Namespace.Name).
Inc()
ctx.String(http.StatusInternalServerError, "")
return
}
machineRegistrations.WithLabelValues("new", "web", "success", machine.Namespace.Name).
Inc()
ctx.Data(http.StatusOK, "application/json; charset=utf-8", respBody)
}
func (h *Headscale) handleMachineRefreshKey(
ctx *gin.Context,
idKey wgkey.Key,
reqisterRequest tailcfg.RegisterRequest,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
log.Debug().
Str("handler", "Registration").
Str("machine", machine.Name).
Msg("We have the OldNodeKey in the database. This is a key refresh")
machine.NodeKey = wgkey.Key(reqisterRequest.NodeKey).HexString()
h.db.Save(&machine)
resp.AuthURL = ""
resp.User = *machine.Namespace.toUser()
respBody, err := encode(resp, &idKey, h.privateKey)
if err != nil {
log.Error().
Str("handler", "Registration").
Err(err).
Msg("Cannot encode message")
ctx.String(http.StatusInternalServerError, "Extremely sad!")
return
}
ctx.Data(http.StatusOK, "application/json; charset=utf-8", respBody)
}
func (h *Headscale) handleMachineRegistrationNew(
ctx *gin.Context,
idKey wgkey.Key,
reqisterRequest tailcfg.RegisterRequest,
machine Machine,
) {
resp := tailcfg.RegisterResponse{}
// The machine registration is new, redirect the client to the registration URL
log.Debug().
Str("handler", "Registration").
Str("machine", machine.Name).
Msg("The node is sending us a new NodeKey, sending auth url")
if h.cfg.OIDC.Issuer != "" {
resp.AuthURL = fmt.Sprintf(
"%s/oidc/register/%s",
strings.TrimSuffix(h.cfg.ServerURL, "/"),
idKey.HexString(),
)
} else {
resp.AuthURL = fmt.Sprintf("%s/register?key=%s",
strings.TrimSuffix(h.cfg.ServerURL, "/"), idKey.HexString())
}
// save the requested expiry time for retrieval later in the authentication flow
machine.RequestedExpiry = &reqisterRequest.Expiry
machine.NodeKey = wgkey.Key(reqisterRequest.NodeKey).HexString() // save the NodeKey
h.db.Save(&machine)
respBody, err := encode(resp, &idKey, h.privateKey)
if err != nil {
log.Error().
Str("handler", "Registration").
Err(err).
Msg("Cannot encode message")
ctx.String(http.StatusInternalServerError, "")
return
}
ctx.Data(http.StatusOK, "application/json; charset=utf-8", respBody)
}
func (h *Headscale) handleAuthKey(
ctx *gin.Context,
idKey wgkey.Key,
reqisterRequest tailcfg.RegisterRequest,
machine Machine,
) {
log.Debug().
Str("func", "handleAuthKey").
Str("machine", reqisterRequest.Hostinfo.Hostname).
Msgf("Processing auth key for %s", reqisterRequest.Hostinfo.Hostname)
resp := tailcfg.RegisterResponse{}
pak, err := h.checkKeyValidity(reqisterRequest.Auth.AuthKey)
if err != nil {
log.Error().
Str("func", "handleAuthKey").
Str("machine", machine.Name).
Err(err).
Msg("Failed authentication via AuthKey")
resp.MachineAuthorized = false
respBody, err := encode(resp, &idKey, h.privateKey)
if err != nil {
log.Error().
Str("func", "handleAuthKey").
Str("machine", machine.Name).
Err(err).
Msg("Cannot encode message")
ctx.String(http.StatusInternalServerError, "")
machineRegistrations.WithLabelValues("new", "authkey", "error", machine.Namespace.Name).
Inc()
return
}
ctx.Data(http.StatusUnauthorized, "application/json; charset=utf-8", respBody)
log.Error().
Str("func", "handleAuthKey").
Str("machine", machine.Name).
Msg("Failed authentication via AuthKey")
machineRegistrations.WithLabelValues("new", "authkey", "error", machine.Namespace.Name).
Inc()
return
}
log.Debug().
Str("func", "handleAuthKey").
Str("machine", machine.Name).
Msg("Authentication key was valid, proceeding to acquire an IP address")
ip, err := h.getAvailableIP()
if err != nil {
log.Error().
Str("func", "handleAuthKey").
Str("machine", machine.Name).
Msg("Failed to find an available IP")
machineRegistrations.WithLabelValues("new", "authkey", "error", machine.Namespace.Name).
Inc()
return
}
log.Info().
Str("func", "handleAuthKey").
Str("machine", machine.Name).
Str("ip", ip.String()).
Msgf("Assigning %s to %s", ip, machine.Name)
machine.AuthKeyID = uint(pak.ID)
machine.IPAddress = ip.String()
machine.NamespaceID = pak.NamespaceID
machine.NodeKey = wgkey.Key(reqisterRequest.NodeKey).
HexString()
// we update it just in case
machine.Registered = true
machine.RegisterMethod = RegisterMethodAuthKey
h.db.Save(&machine)
pak.Used = true
h.db.Save(&pak)
resp.MachineAuthorized = true
resp.User = *pak.Namespace.toUser()
respBody, err := encode(resp, &idKey, h.privateKey)
if err != nil {
log.Error().
Str("func", "handleAuthKey").
Str("machine", machine.Name).
Err(err).
Msg("Cannot encode message")
machineRegistrations.WithLabelValues("new", "authkey", "error", machine.Namespace.Name).
Inc()
ctx.String(http.StatusInternalServerError, "Extremely sad!")
return
}
machineRegistrations.WithLabelValues("new", "authkey", "success", machine.Namespace.Name).
Inc()
ctx.Data(http.StatusOK, "application/json; charset=utf-8", respBody)
log.Info().
Str("func", "handleAuthKey").
Str("machine", machine.Name).
Str("ip", ip.String()).
Msg("Successfully authenticated via AuthKey")
}