TUN-4063: Cleanup dependencies between packages.

- Move packages the provide generic functionality (such as config) from `cmd` subtree to top level. - Remove all dependencies on `cmd` subtree from top level packages. - Consolidate all code dealing with token generation and transfer to a single cohesive package.
2025-07-27 16:59:57 +00:00 · 2021-03-08 10:46:23 -06:00
parent d83d6d54ed
commit 39065377b5
47 changed files with 246 additions and 236 deletions
--- a/config/configuration.go
+++ b/config/configuration.go
@@ -0,0 +1,380 @@
+package config
+
+import (
+	"fmt"
+	"io"
+	"net/url"
+	"os"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"github.com/mitchellh/go-homedir"
+	"github.com/pkg/errors"
+	"github.com/rs/zerolog"
+	"github.com/urfave/cli/v2"
+	"gopkg.in/yaml.v2"
+
+	"github.com/cloudflare/cloudflared/validation"
+)
+
+var (
+	// DefaultConfigFiles is the file names from which we attempt to read configuration.
+	DefaultConfigFiles = []string{"config.yml", "config.yaml"}
+
+	// DefaultUnixConfigLocation is the primary location to find a config file
+	DefaultUnixConfigLocation = "/usr/local/etc/cloudflared"
+
+	// DefaultUnixLogLocation is the primary location to find log files
+	DefaultUnixLogLocation = "/var/log/cloudflared"
+
+	// Launchd doesn't set root env variables, so there is default
+	// Windows default config dir was ~/cloudflare-warp in documentation; let's keep it compatible
+	defaultUserConfigDirs = []string{"~/.cloudflared", "~/.cloudflare-warp", "~/cloudflare-warp"}
+	defaultNixConfigDirs  = []string{"/etc/cloudflared", DefaultUnixConfigLocation}
+
+	ErrNoConfigFile = fmt.Errorf("Cannot determine default configuration path. No file %v in %v", DefaultConfigFiles, DefaultConfigSearchDirectories())
+)
+
+const (
+	DefaultCredentialFile = "cert.pem"
+
+	// BastionFlag is to enable bastion, or jump host, operation
+	BastionFlag = "bastion"
+)
+
+// DefaultConfigDirectory returns the default directory of the config file
+func DefaultConfigDirectory() string {
+	if runtime.GOOS == "windows" {
+		path := os.Getenv("CFDPATH")
+		if path == "" {
+			path = filepath.Join(os.Getenv("ProgramFiles(x86)"), "cloudflared")
+			if _, err := os.Stat(path); os.IsNotExist(err) { //doesn't exist, so return an empty failure string
+				return ""
+			}
+		}
+		return path
+	}
+	return DefaultUnixConfigLocation
+}
+
+// DefaultLogDirectory returns the default directory for log files
+func DefaultLogDirectory() string {
+	if runtime.GOOS == "windows" {
+		return DefaultConfigDirectory()
+	}
+	return DefaultUnixLogLocation
+}
+
+// DefaultConfigPath returns the default location of a config file
+func DefaultConfigPath() string {
+	dir := DefaultConfigDirectory()
+	if dir == "" {
+		return DefaultConfigFiles[0]
+	}
+	return filepath.Join(dir, DefaultConfigFiles[0])
+}
+
+// DefaultConfigSearchDirectories returns the default folder locations of the config
+func DefaultConfigSearchDirectories() []string {
+	dirs := make([]string, len(defaultUserConfigDirs))
+	copy(dirs, defaultUserConfigDirs)
+	if runtime.GOOS != "windows" {
+		dirs = append(dirs, defaultNixConfigDirs...)
+	}
+	return dirs
+}
+
+// FileExists checks to see if a file exist at the provided path.
+func FileExists(path string) (bool, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			// ignore missing files
+			return false, nil
+		}
+		return false, err
+	}
+	_ = f.Close()
+	return true, nil
+}
+
+// FindDefaultConfigPath returns the first path that contains a config file.
+// If none of the combination of DefaultConfigSearchDirectories() and DefaultConfigFiles
+// contains a config file, return empty string.
+func FindDefaultConfigPath() string {
+	for _, configDir := range DefaultConfigSearchDirectories() {
+		for _, configFile := range DefaultConfigFiles {
+			dirPath, err := homedir.Expand(configDir)
+			if err != nil {
+				continue
+			}
+			path := filepath.Join(dirPath, configFile)
+			if ok, _ := FileExists(path); ok {
+				return path
+			}
+		}
+	}
+	return ""
+}
+
+// FindOrCreateConfigPath returns the first path that contains a config file
+// or creates one in the primary default path if it doesn't exist
+func FindOrCreateConfigPath() string {
+	path := FindDefaultConfigPath()
+
+	if path == "" {
+		// create the default directory if it doesn't exist
+		path = DefaultConfigPath()
+		if err := os.MkdirAll(filepath.Dir(path), os.ModePerm); err != nil {
+			return ""
+		}
+
+		// write a new config file out
+		file, err := os.Create(path)
+		if err != nil {
+			return ""
+		}
+		defer file.Close()
+
+		logDir := DefaultLogDirectory()
+		_ = os.MkdirAll(logDir, os.ModePerm) //try and create it. Doesn't matter if it succeed or not, only byproduct will be no logs
+
+		c := Root{
+			LogDirectory: logDir,
+		}
+		if err := yaml.NewEncoder(file).Encode(&c); err != nil {
+			return ""
+		}
+	}
+
+	return path
+}
+
+// ValidateUnixSocket ensures --unix-socket param is used exclusively
+// i.e. it fails if a user specifies both --url and --unix-socket
+func ValidateUnixSocket(c *cli.Context) (string, error) {
+	if c.IsSet("unix-socket") && (c.IsSet("url") || c.NArg() > 0) {
+		return "", errors.New("--unix-socket must be used exclusivly.")
+	}
+	return c.String("unix-socket"), nil
+}
+
+// ValidateUrl will validate url flag correctness. It can be either from --url or argument
+// Notice ValidateUnixSocket, it will enforce --unix-socket is not used with --url or argument
+func ValidateUrl(c *cli.Context, allowURLFromArgs bool) (*url.URL, error) {
+	var url = c.String("url")
+	if allowURLFromArgs && c.NArg() > 0 {
+		if c.IsSet("url") {
+			return nil, errors.New("Specified origin urls using both --url and argument. Decide which one you want, I can only support one.")
+		}
+		url = c.Args().Get(0)
+	}
+	validUrl, err := validation.ValidateUrl(url)
+	return validUrl, err
+}
+
+type UnvalidatedIngressRule struct {
+	Hostname      string
+	Path          string
+	Service       string
+	OriginRequest OriginRequestConfig `yaml:"originRequest"`
+}
+
+// OriginRequestConfig is a set of optional fields that users may set to
+// customize how cloudflared sends requests to origin services. It is used to set
+// up general config that apply to all rules, and also, specific per-rule
+// config.
+// Note: To specify a time.Duration in go-yaml, use e.g. "3s" or "24h".
+type OriginRequestConfig struct {
+	// HTTP proxy timeout for establishing a new connection
+	ConnectTimeout *time.Duration `yaml:"connectTimeout"`
+	// HTTP proxy timeout for completing a TLS handshake
+	TLSTimeout *time.Duration `yaml:"tlsTimeout"`
+	// HTTP proxy TCP keepalive duration
+	TCPKeepAlive *time.Duration `yaml:"tcpKeepAlive"`
+	// HTTP proxy should disable "happy eyeballs" for IPv4/v6 fallback
+	NoHappyEyeballs *bool `yaml:"noHappyEyeballs"`
+	// HTTP proxy maximum keepalive connection pool size
+	KeepAliveConnections *int `yaml:"keepAliveConnections"`
+	// HTTP proxy timeout for closing an idle connection
+	KeepAliveTimeout *time.Duration `yaml:"keepAliveTimeout"`
+	// Sets the HTTP Host header for the local webserver.
+	HTTPHostHeader *string `yaml:"httpHostHeader"`
+	// Hostname on the origin server certificate.
+	OriginServerName *string `yaml:"originServerName"`
+	// Path to the CA for the certificate of your origin.
+	// This option should be used only if your certificate is not signed by Cloudflare.
+	CAPool *string `yaml:"caPool"`
+	// Disables TLS verification of the certificate presented by your origin.
+	// Will allow any certificate from the origin to be accepted.
+	// Note: The connection from your machine to Cloudflare's Edge is still encrypted.
+	NoTLSVerify *bool `yaml:"noTLSVerify"`
+	// Disables chunked transfer encoding.
+	// Useful if you are running a WSGI server.
+	DisableChunkedEncoding *bool `yaml:"disableChunkedEncoding"`
+	// Runs as jump host
+	BastionMode *bool `yaml:"bastionMode"`
+	// Listen address for the proxy.
+	ProxyAddress *string `yaml:"proxyAddress"`
+	// Listen port for the proxy.
+	ProxyPort *uint `yaml:"proxyPort"`
+	// Valid options are 'socks' or empty.
+	ProxyType *string `yaml:"proxyType"`
+}
+
+type Configuration struct {
+	TunnelID      string `yaml:"tunnel"`
+	Ingress       []UnvalidatedIngressRule
+	WarpRouting   WarpRoutingConfig   `yaml:"warp-routing"`
+	OriginRequest OriginRequestConfig `yaml:"originRequest"`
+	sourceFile    string
+}
+
+type WarpRoutingConfig struct {
+	Enabled bool `yaml:"enabled"`
+}
+
+type configFileSettings struct {
+	Configuration `yaml:",inline"`
+	// older settings will be aggregated into the generic map, should be read via cli.Context
+	Settings map[string]interface{} `yaml:",inline"`
+}
+
+func (c *Configuration) Source() string {
+	return c.sourceFile
+}
+
+func (c *configFileSettings) Int(name string) (int, error) {
+	if raw, ok := c.Settings[name]; ok {
+		if v, ok := raw.(int); ok {
+			return v, nil
+		}
+		return 0, fmt.Errorf("expected int found %T for %s", raw, name)
+	}
+	return 0, nil
+}
+
+func (c *configFileSettings) Duration(name string) (time.Duration, error) {
+	if raw, ok := c.Settings[name]; ok {
+		switch v := raw.(type) {
+		case time.Duration:
+			return v, nil
+		case string:
+			return time.ParseDuration(v)
+		}
+		return 0, fmt.Errorf("expected duration found %T for %s", raw, name)
+	}
+	return 0, nil
+}
+
+func (c *configFileSettings) Float64(name string) (float64, error) {
+	if raw, ok := c.Settings[name]; ok {
+		if v, ok := raw.(float64); ok {
+			return v, nil
+		}
+		return 0, fmt.Errorf("expected float found %T for %s", raw, name)
+	}
+	return 0, nil
+}
+
+func (c *configFileSettings) String(name string) (string, error) {
+	if raw, ok := c.Settings[name]; ok {
+		if v, ok := raw.(string); ok {
+			return v, nil
+		}
+		return "", fmt.Errorf("expected string found %T for %s", raw, name)
+	}
+	return "", nil
+}
+
+func (c *configFileSettings) StringSlice(name string) ([]string, error) {
+	if raw, ok := c.Settings[name]; ok {
+		if slice, ok := raw.([]interface{}); ok {
+			strSlice := make([]string, len(slice))
+			for i, v := range slice {
+				str, ok := v.(string)
+				if !ok {
+					return nil, fmt.Errorf("expected string, found %T for %v", i, v)
+				}
+				strSlice[i] = str
+			}
+			return strSlice, nil
+		}
+		return nil, fmt.Errorf("expected string slice found %T for %s", raw, name)
+	}
+	return nil, nil
+}
+
+func (c *configFileSettings) IntSlice(name string) ([]int, error) {
+	if raw, ok := c.Settings[name]; ok {
+		if slice, ok := raw.([]interface{}); ok {
+			intSlice := make([]int, len(slice))
+			for i, v := range slice {
+				str, ok := v.(int)
+				if !ok {
+					return nil, fmt.Errorf("expected int, found %T for %v ", v, v)
+				}
+				intSlice[i] = str
+			}
+			return intSlice, nil
+		}
+		if v, ok := raw.([]int); ok {
+			return v, nil
+		}
+		return nil, fmt.Errorf("expected int slice found %T for %s", raw, name)
+	}
+	return nil, nil
+}
+
+func (c *configFileSettings) Generic(name string) (cli.Generic, error) {
+	return nil, errors.New("option type Generic not supported")
+}
+
+func (c *configFileSettings) Bool(name string) (bool, error) {
+	if raw, ok := c.Settings[name]; ok {
+		if v, ok := raw.(bool); ok {
+			return v, nil
+		}
+		return false, fmt.Errorf("expected boolean found %T for %s", raw, name)
+	}
+	return false, nil
+}
+
+var configuration configFileSettings
+
+func GetConfiguration() *Configuration {
+	return &configuration.Configuration
+}
+
+// ReadConfigFile returns InputSourceContext initialized from the configuration file.
+// On repeat calls returns with the same file, returns without reading the file again; however,
+// if value of "config" flag changes, will read the new config file
+func ReadConfigFile(c *cli.Context, log *zerolog.Logger) (*configFileSettings, error) {
+	configFile := c.String("config")
+	if configuration.Source() == configFile || configFile == "" {
+		if configuration.Source() == "" {
+			return nil, ErrNoConfigFile
+		}
+		return &configuration, nil
+	}
+
+	log.Debug().Msgf("Loading configuration from %s", configFile)
+	file, err := os.Open(configFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			err = ErrNoConfigFile
+		}
+		return nil, err
+	}
+	defer file.Close()
+	if err := yaml.NewDecoder(file).Decode(&configuration); err != nil {
+		if err == io.EOF {
+			log.Error().Msgf("Configuration file %s was empty", configFile)
+			return &configuration, nil
+		}
+		return nil, errors.Wrap(err, "error parsing YAML in config file at "+configFile)
+	}
+	configuration.sourceFile = configFile
+	return &configuration, nil
+}
--- a/config/configuration_test.go
+++ b/config/configuration_test.go
@@ -0,0 +1,83 @@
+package config
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/yaml.v2"
+)
+
+func TestConfigFileSettings(t *testing.T) {
+	var (
+		firstIngress = UnvalidatedIngressRule{
+			Hostname: "tunnel1.example.com",
+			Path:     "/id",
+			Service:  "https://localhost:8000",
+		}
+		secondIngress = UnvalidatedIngressRule{
+			Hostname: "*",
+			Path:     "",
+			Service:  "https://localhost:8001",
+		}
+		warpRouting = WarpRoutingConfig{
+			Enabled: true,
+		}
+	)
+	rawYAML := `
+tunnel: config-file-test
+ingress:
+ - hostname: tunnel1.example.com
+   path: /id
+   service: https://localhost:8000
+ - hostname: "*"
+   service: https://localhost:8001
+warp-routing: 
+  enabled: true
+retries: 5
+grace-period: 30s
+percentage: 3.14
+hostname: example.com
+tag:
+ - test
+ - central-1
+counters:
+ - 123
+ - 456
+`
+	var config configFileSettings
+	err := yaml.Unmarshal([]byte(rawYAML), &config)
+	assert.NoError(t, err)
+
+	assert.Equal(t, "config-file-test", config.TunnelID)
+	assert.Equal(t, firstIngress, config.Ingress[0])
+	assert.Equal(t, secondIngress, config.Ingress[1])
+	assert.Equal(t, warpRouting, config.WarpRouting)
+
+	retries, err := config.Int("retries")
+	assert.NoError(t, err)
+	assert.Equal(t, 5, retries)
+
+	gracePeriod, err := config.Duration("grace-period")
+	assert.NoError(t, err)
+	assert.Equal(t, time.Second*30, gracePeriod)
+
+	percentage, err := config.Float64("percentage")
+	assert.NoError(t, err)
+	assert.Equal(t, 3.14, percentage)
+
+	hostname, err := config.String("hostname")
+	assert.NoError(t, err)
+	assert.Equal(t, "example.com", hostname)
+
+	tags, err := config.StringSlice("tag")
+	assert.NoError(t, err)
+	assert.Equal(t, "test", tags[0])
+	assert.Equal(t, "central-1", tags[1])
+
+	counters, err := config.IntSlice("counters")
+	assert.NoError(t, err)
+	assert.Equal(t, 123, counters[0])
+	assert.Equal(t, 456, counters[1])
+
+}
--- a/config/manager.go
+++ b/config/manager.go
@@ -0,0 +1,112 @@
+package config
+
+import (
+	"io"
+	"os"
+
+	"github.com/cloudflare/cloudflared/watcher"
+
+	"github.com/pkg/errors"
+	"github.com/rs/zerolog"
+	"gopkg.in/yaml.v2"
+)
+
+// Notifier sends out config updates
+type Notifier interface {
+	ConfigDidUpdate(Root)
+}
+
+// Manager is the base functions of the config manager
+type Manager interface {
+	Start(Notifier) error
+	Shutdown()
+}
+
+// FileManager watches the yaml config for changes
+// sends updates to the service to reconfigure to match the updated config
+type FileManager struct {
+	watcher    watcher.Notifier
+	notifier   Notifier
+	configPath string
+	log        *zerolog.Logger
+	ReadConfig func(string, *zerolog.Logger) (Root, error)
+}
+
+// NewFileManager creates a config manager
+func NewFileManager(watcher watcher.Notifier, configPath string, log *zerolog.Logger) (*FileManager, error) {
+	m := &FileManager{
+		watcher:    watcher,
+		configPath: configPath,
+		log:        log,
+		ReadConfig: readConfigFromPath,
+	}
+	err := watcher.Add(configPath)
+	return m, err
+}
+
+// Start starts the runloop to watch for config changes
+func (m *FileManager) Start(notifier Notifier) error {
+	m.notifier = notifier
+
+	// update the notifier with a fresh config on start
+	config, err := m.GetConfig()
+	if err != nil {
+		return err
+	}
+	notifier.ConfigDidUpdate(config)
+
+	m.watcher.Start(m)
+	return nil
+}
+
+// GetConfig reads the yaml file from the disk
+func (m *FileManager) GetConfig() (Root, error) {
+	return m.ReadConfig(m.configPath, m.log)
+}
+
+// Shutdown stops the watcher
+func (m *FileManager) Shutdown() {
+	m.watcher.Shutdown()
+}
+
+func readConfigFromPath(configPath string, log *zerolog.Logger) (Root, error) {
+	if configPath == "" {
+		return Root{}, errors.New("unable to find config file")
+	}
+
+	file, err := os.Open(configPath)
+	if err != nil {
+		return Root{}, err
+	}
+	defer file.Close()
+
+	var config Root
+	if err := yaml.NewDecoder(file).Decode(&config); err != nil {
+		if err == io.EOF {
+			log.Error().Msgf("Configuration file %s was empty", configPath)
+			return Root{}, nil
+		}
+		return Root{}, errors.Wrap(err, "error parsing YAML in config file at "+configPath)
+	}
+
+	return config, nil
+}
+
+// File change notifications from the watcher
+
+// WatcherItemDidChange triggers when the yaml config is updated
+// sends the updated config to the service to reload its state
+func (m *FileManager) WatcherItemDidChange(filepath string) {
+	config, err := m.GetConfig()
+	if err != nil {
+		m.log.Err(err).Msg("Failed to read new config")
+		return
+	}
+	m.log.Info().Msg("Config file has been updated")
+	m.notifier.ConfigDidUpdate(config)
+}
+
+// WatcherDidError notifies of errors with the file watcher
+func (m *FileManager) WatcherDidError(err error) {
+	m.log.Err(err).Msg("Config watcher encountered an error")
+}
--- a/config/manager_test.go
+++ b/config/manager_test.go
@@ -0,0 +1,88 @@
+package config
+
+import (
+	"os"
+	"testing"
+
+	"github.com/cloudflare/cloudflared/watcher"
+
+	"github.com/rs/zerolog"
+	"github.com/stretchr/testify/assert"
+)
+
+type mockNotifier struct {
+	configs []Root
+}
+
+func (n *mockNotifier) ConfigDidUpdate(c Root) {
+	n.configs = append(n.configs, c)
+}
+
+type mockFileWatcher struct {
+	path     string
+	notifier watcher.Notification
+	ready    chan struct{}
+}
+
+func (w *mockFileWatcher) Start(n watcher.Notification) {
+	w.notifier = n
+	w.ready <- struct{}{}
+}
+
+func (w *mockFileWatcher) Add(string) error {
+	return nil
+}
+
+func (w *mockFileWatcher) Shutdown() {
+
+}
+
+func (w *mockFileWatcher) TriggerChange() {
+	w.notifier.WatcherItemDidChange(w.path)
+}
+
+func TestConfigChanged(t *testing.T) {
+	filePath := "config.yaml"
+	f, err := os.Create(filePath)
+	assert.NoError(t, err)
+	defer func() {
+		_ = f.Close()
+		_ = os.Remove(filePath)
+	}()
+	c := &Root{
+		Forwarders: []Forwarder{
+			{
+				URL:      "test.daltoniam.com",
+				Listener: "127.0.0.1:8080",
+			},
+		},
+	}
+	configRead := func(configPath string, log *zerolog.Logger) (Root, error) {
+		return *c, nil
+	}
+	wait := make(chan struct{})
+	w := &mockFileWatcher{path: filePath, ready: wait}
+
+	log := zerolog.Nop()
+
+	service, err := NewFileManager(w, filePath, &log)
+	service.ReadConfig = configRead
+	assert.NoError(t, err)
+
+	n := &mockNotifier{}
+	go service.Start(n)
+
+	<-wait
+	c.Forwarders = append(c.Forwarders, Forwarder{URL: "add.daltoniam.com", Listener: "127.0.0.1:8081"})
+	w.TriggerChange()
+
+	service.Shutdown()
+
+	assert.Len(t, n.configs, 2, "did not get 2 config updates as expected")
+	assert.Len(t, n.configs[0].Forwarders, 1, "not the amount of forwarders expected")
+	assert.Len(t, n.configs[1].Forwarders, 2, "not the amount of forwarders expected")
+
+	assert.Equal(t, n.configs[0].Forwarders[0].Hash(), c.Forwarders[0].Hash(), "forwarder hashes don't match")
+	assert.Equal(t, n.configs[1].Forwarders[0].Hash(), c.Forwarders[0].Hash(), "forwarder hashes don't match")
+	assert.Equal(t, n.configs[1].Forwarders[1].Hash(), c.Forwarders[1].Hash(), "forwarder hashes don't match")
+}
--- a/config/model.go
+++ b/config/model.go
@@ -0,0 +1,113 @@
+package config
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/cloudflare/cloudflared/tunneldns"
+)
+
+// Forwarder represents a client side listener to forward traffic to the edge
+type Forwarder struct {
+	URL           string `json:"url"`
+	Listener      string `json:"listener"`
+	TokenClientID string `json:"service_token_id" yaml:"serviceTokenID"`
+	TokenSecret   string `json:"secret_token_id" yaml:"serviceTokenSecret"`
+	Destination   string `json:"destination"`
+}
+
+// Tunnel represents a tunnel that should be started
+type Tunnel struct {
+	URL          string `json:"url"`
+	Origin       string `json:"origin"`
+	ProtocolType string `json:"type"`
+}
+
+// DNSResolver represents a client side DNS resolver
+type DNSResolver struct {
+	Enabled                bool     `json:"enabled"`
+	Address                string   `json:"address,omitempty"`
+	Port                   uint16   `json:"port,omitempty"`
+	Upstreams              []string `json:"upstreams,omitempty"`
+	Bootstraps             []string `json:"bootstraps,omitempty"`
+	MaxUpstreamConnections int      `json:"max_upstream_connections,omitempty"`
+}
+
+// Root is the base options to configure the service
+type Root struct {
+	LogDirectory string      `json:"log_directory" yaml:"logDirectory,omitempty"`
+	LogLevel     string      `json:"log_level" yaml:"logLevel,omitempty"`
+	Forwarders   []Forwarder `json:"forwarders,omitempty" yaml:"forwarders,omitempty"`
+	Tunnels      []Tunnel    `json:"tunnels,omitempty" yaml:"tunnels,omitempty"`
+	Resolver     DNSResolver `json:"resolver,omitempty" yaml:"resolver,omitempty"`
+}
+
+// Hash returns the computed values to see if the forwarder values change
+func (f *Forwarder) Hash() string {
+	h := md5.New()
+	io.WriteString(h, f.URL)
+	io.WriteString(h, f.Listener)
+	io.WriteString(h, f.TokenClientID)
+	io.WriteString(h, f.TokenSecret)
+	io.WriteString(h, f.Destination)
+	return fmt.Sprintf("%x", h.Sum(nil))
+}
+
+// Hash returns the computed values to see if the forwarder values change
+func (r *DNSResolver) Hash() string {
+	h := md5.New()
+	io.WriteString(h, r.Address)
+	io.WriteString(h, strings.Join(r.Bootstraps, ","))
+	io.WriteString(h, strings.Join(r.Upstreams, ","))
+	io.WriteString(h, fmt.Sprintf("%d", r.Port))
+	io.WriteString(h, fmt.Sprintf("%d", r.MaxUpstreamConnections))
+	io.WriteString(h, fmt.Sprintf("%v", r.Enabled))
+	return fmt.Sprintf("%x", h.Sum(nil))
+}
+
+// EnabledOrDefault returns the enabled property
+func (r *DNSResolver) EnabledOrDefault() bool {
+	return r.Enabled
+}
+
+// AddressOrDefault returns the address or returns the default if empty
+func (r *DNSResolver) AddressOrDefault() string {
+	if r.Address != "" {
+		return r.Address
+	}
+	return "localhost"
+}
+
+// PortOrDefault return the port or returns the default if 0
+func (r *DNSResolver) PortOrDefault() uint16 {
+	if r.Port > 0 {
+		return r.Port
+	}
+	return 53
+}
+
+// UpstreamsOrDefault returns the upstreams or returns the default if empty
+func (r *DNSResolver) UpstreamsOrDefault() []string {
+	if len(r.Upstreams) > 0 {
+		return r.Upstreams
+	}
+	return []string{"https://1.1.1.1/dns-query", "https://1.0.0.1/dns-query"}
+}
+
+// BootstrapsOrDefault returns the bootstraps or returns the default if empty
+func (r *DNSResolver) BootstrapsOrDefault() []string {
+	if len(r.Bootstraps) > 0 {
+		return r.Bootstraps
+	}
+	return []string{"https://162.159.36.1/dns-query", "https://162.159.46.1/dns-query", "https://[2606:4700:4700::1111]/dns-query", "https://[2606:4700:4700::1001]/dns-query"}
+}
+
+// MaxUpstreamConnectionsOrDefault return the max upstream connections or returns the default if negative
+func (r *DNSResolver) MaxUpstreamConnectionsOrDefault() int {
+	if r.MaxUpstreamConnections >= 0 {
+		return r.MaxUpstreamConnections
+	}
+	return tunneldns.MaxUpstreamConnsDefault
+}