config.go

//go:generate go run github.com/abice/go-enum -f=$GOFILE --marshal --names
package config

import (
	"errors"
	"fmt"
	"net"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/miekg/dns"

	"github.com/hako/durafmt"

	"github.com/0xERR0R/blocky/log"
	"github.com/creasty/defaults"
	"gopkg.in/yaml.v2"
)

const (
	udpPort   = 53
	tlsPort   = 853
	httpsPort = 443
)

// NetProtocol resolver protocol ENUM(
// tcp+udp // TCP and UDP protocols
// tcp-tls // TCP-TLS protocol
// https // HTTPS protocol
// )
type NetProtocol uint16

// IPVersion represents IP protocol version(s). ENUM(
// dual // IPv4 and IPv6
// v4   // IPv4 only
// v6   // IPv6 only
// )
type IPVersion uint8

func (ipv IPVersion) Net() string {
	switch ipv {
	case IPVersionDual:
		return "ip"
	case IPVersionV4:
		return "ip4"
	case IPVersionV6:
		return "ip6"
	}

	panic(fmt.Errorf("bad value: %s", ipv))
}

func (ipv IPVersion) QTypes() []dns.Type {
	switch ipv {
	case IPVersionDual:
		return []dns.Type{dns.Type(dns.TypeA), dns.Type(dns.TypeAAAA)}
	case IPVersionV4:
		return []dns.Type{dns.Type(dns.TypeA)}
	case IPVersionV6:
		return []dns.Type{dns.Type(dns.TypeAAAA)}
	}

	panic(fmt.Errorf("bad value: %s", ipv))
}

// QueryLogType type of the query log ENUM(
// console // use logger as fallback
// none // no logging
// mysql // MySQL or MariaDB database
// postgresql // PostgreSQL database
// csv // CSV file per day
// csv-client // CSV file per day and client
// )
type QueryLogType int16

// StartStrategyType upstart strategy ENUM(
// blocking // synchronously download blocking lists on startup
// failOnError // synchronously download blocking lists on startup and shutdown on error
// fast // asyncronously download blocking lists on startup
// )
type StartStrategyType uint16

// QueryLogField data field to be logged
// ENUM(clientIP,clientName,responseReason,responseAnswer,question,duration)
type QueryLogField string

type QType dns.Type

func (c QType) String() string {
	return dns.Type(c).String()
}

type QTypeSet map[QType]struct{}

func NewQTypeSet(qTypes ...dns.Type) QTypeSet {
	s := make(QTypeSet, len(qTypes))

	for _, qType := range qTypes {
		s.Insert(qType)
	}

	return s
}

func (s QTypeSet) Contains(qType dns.Type) bool {
	_, found := s[QType(qType)]

	return found
}

func (s *QTypeSet) Insert(qType dns.Type) {
	if *s == nil {
		*s = make(QTypeSet, 1)
	}

	(*s)[QType(qType)] = struct{}{}
}

type Duration time.Duration

func (c *Duration) String() string {
	return durafmt.Parse(time.Duration(*c)).String()
}

//nolint:gochecknoglobals
var netDefaultPort = map[NetProtocol]uint16{
	NetProtocolTcpUdp: udpPort,
	NetProtocolTcpTls: tlsPort,
	NetProtocolHttps:  httpsPort,
}

// Upstream is the definition of external DNS server
type Upstream struct {
	Net        NetProtocol
	Host       string
	Port       uint16
	Path       string
	CommonName string // Common Name to use for certificate verification; optional. "" uses .Host
}

// IsDefault returns true if u is the default value
func (u *Upstream) IsDefault() bool {
	return *u == Upstream{}
}

// String returns the string representation of u
func (u *Upstream) String() string {
	if u.IsDefault() {
		return "no upstream"
	}

	var sb strings.Builder

	sb.WriteString(u.Net.String())
	sb.WriteRune(':')

	if u.Net == NetProtocolHttps {
		sb.WriteString("//")
	}

	isIPv6 := strings.ContainsRune(u.Host, ':')
	if isIPv6 {
		sb.WriteRune('[')
		sb.WriteString(u.Host)
		sb.WriteRune(']')
	} else {
		sb.WriteString(u.Host)
	}

	if u.Port != netDefaultPort[u.Net] {
		sb.WriteRune(':')
		sb.WriteString(fmt.Sprint(u.Port))
	}

	if u.Path != "" {
		sb.WriteString(u.Path)
	}

	return sb.String()
}

// UnmarshalYAML creates Upstream from YAML
func (u *Upstream) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var s string
	if err := unmarshal(&s); err != nil {
		return err
	}

	upstream, err := ParseUpstream(s)
	if err != nil {
		return fmt.Errorf("can't convert upstream '%s': %w", s, err)
	}

	*u = upstream

	return nil
}

// ListenConfig is a list of address(es) to listen on
type ListenConfig []string

// UnmarshalYAML creates ListenConfig from YAML
func (l *ListenConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var addresses string
	if err := unmarshal(&addresses); err != nil {
		return err
	}

	*l = strings.Split(addresses, ",")

	return nil
}

// UnmarshalYAML creates BootstrapConfig from YAML
func (b *BootstrapConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
	if err := unmarshal(&b.Upstream); err == nil {
		return nil
	}

	// bootstrapConfig is used to avoid infinite recursion:
	// if we used BootstrapConfig, unmarshal would just call us again.
	var c bootstrapConfig
	if err := unmarshal(&c); err != nil {
		return err
	}

	*b = BootstrapConfig(c)

	return nil
}

// UnmarshalYAML creates ConditionalUpstreamMapping from YAML
func (c *ConditionalUpstreamMapping) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var input map[string]string
	if err := unmarshal(&input); err != nil {
		return err
	}

	result := make(map[string][]Upstream, len(input))

	for k, v := range input {
		var upstreams []Upstream

		for _, part := range strings.Split(v, ",") {
			upstream, err := ParseUpstream(strings.TrimSpace(part))
			if err != nil {
				return fmt.Errorf("can't convert upstream '%s': %w", strings.TrimSpace(part), err)
			}

			upstreams = append(upstreams, upstream)
		}

		result[k] = upstreams
	}

	c.Upstreams = result

	return nil
}

// UnmarshalYAML creates CustomDNSMapping from YAML
func (c *CustomDNSMapping) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var input map[string]string
	if err := unmarshal(&input); err != nil {
		return err
	}

	result := make(map[string][]net.IP, len(input))

	for k, v := range input {
		var ips []net.IP

		for _, part := range strings.Split(v, ",") {
			ip := net.ParseIP(strings.TrimSpace(part))
			if ip == nil {
				return fmt.Errorf("invalid IP address '%s'", part)
			}

			ips = append(ips, ip)
		}

		result[k] = ips
	}

	c.HostIPs = result

	return nil
}

// UnmarshalYAML creates Duration from YAML. If no unit is used, uses minutes
func (c *Duration) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var input string
	if err := unmarshal(&input); err != nil {
		return err
	}

	if minutes, err := strconv.Atoi(input); err == nil {
		// duration is defined as number without unit
		// use minutes to ensure back compatibility
		*c = Duration(time.Duration(minutes) * time.Minute)

		return nil
	}

	duration, err := time.ParseDuration(input)
	if err == nil {
		*c = Duration(duration)

		return nil
	}

	return err
}

func (c *QType) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var input string
	if err := unmarshal(&input); err != nil {
		return err
	}

	t, found := dns.StringToType[input]
	if !found {
		types := make([]string, 0, len(dns.StringToType))
		for k := range dns.StringToType {
			types = append(types, k)
		}

		sort.Strings(types)

		return fmt.Errorf("unknown DNS query type: '%s'. Please use following types '%s'",
			input, strings.Join(types, ", "))
	}

	*c = QType(t)

	return nil
}

func (s *QTypeSet) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var input []QType
	if err := unmarshal(&input); err != nil {
		return err
	}

	*s = make(QTypeSet, len(input))

	for _, qType := range input {
		(*s)[qType] = struct{}{}
	}

	return nil
}

var validDomain = regexp.MustCompile(
	`^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])$`)

// ParseUpstream creates new Upstream from passed string in format [net]:host[:port][/path][#commonname]
func ParseUpstream(upstream string) (Upstream, error) {
	var path string

	var port uint16

	commonName, upstream := extractCommonName(upstream)

	n, upstream := extractNet(upstream)

	path, upstream = extractPath(upstream)

	host, portString, err := net.SplitHostPort(upstream)

	// string contains host:port
	if err == nil {
		p, err := ConvertPort(portString)

		if err != nil {
			err = fmt.Errorf("can't convert port to number (1 - 65535) %w", err)

			return Upstream{}, err
		}

		port = p
	} else {
		// only host, use default port
		host = upstream
		port = netDefaultPort[n]

		// trim any IPv6 brackets
		host = strings.TrimPrefix(host, "[")
		host = strings.TrimSuffix(host, "]")
	}

	// validate hostname or ip
	if ip := net.ParseIP(host); ip == nil {
		// is not IP
		if !validDomain.MatchString(host) {
			return Upstream{}, fmt.Errorf("wrong host name '%s'", host)
		}
	}

	return Upstream{
		Net:        n,
		Host:       host,
		Port:       port,
		Path:       path,
		CommonName: commonName,
	}, nil
}

func extractCommonName(in string) (string, string) {
	upstream, cn, _ := strings.Cut(in, "#")

	return cn, upstream
}

func extractPath(in string) (path string, upstream string) {
	slashIdx := strings.Index(in, "/")

	if slashIdx >= 0 {
		path = in[slashIdx:]
		upstream = in[:slashIdx]
	} else {
		upstream = in
	}

	return
}

func extractNet(upstream string) (NetProtocol, string) {
	tcpUDPPrefix := NetProtocolTcpUdp.String() + ":"
	if strings.HasPrefix(upstream, tcpUDPPrefix) {
		return NetProtocolTcpUdp, upstream[len(tcpUDPPrefix):]
	}

	tcpTLSPrefix := NetProtocolTcpTls.String() + ":"
	if strings.HasPrefix(upstream, tcpTLSPrefix) {
		return NetProtocolTcpTls, upstream[len(tcpTLSPrefix):]
	}

	httpsPrefix := NetProtocolHttps.String() + ":"
	if strings.HasPrefix(upstream, httpsPrefix) {
		return NetProtocolHttps, strings.TrimPrefix(upstream[len(httpsPrefix):], "//")
	}

	return NetProtocolTcpUdp, upstream
}

// Config main configuration
//
//nolint:maligned
type Config struct {
	Upstream            UpstreamConfig            `yaml:"upstream"`
	UpstreamTimeout     Duration                  `yaml:"upstreamTimeout" default:"2s"`
	ConnectIPVersion    IPVersion                 `yaml:"connectIPVersion"`
	CustomDNS           CustomDNSConfig           `yaml:"customDNS"`
	Conditional         ConditionalUpstreamConfig `yaml:"conditional"`
	Blocking            BlockingConfig            `yaml:"blocking"`
	ClientLookup        ClientLookupConfig        `yaml:"clientLookup"`
	Caching             CachingConfig             `yaml:"caching"`
	QueryLog            QueryLogConfig            `yaml:"queryLog"`
	Prometheus          PrometheusConfig          `yaml:"prometheus"`
	Redis               RedisConfig               `yaml:"redis"`
	LogLevel            log.Level                 `yaml:"logLevel" default:"info"`
	LogFormat           log.FormatType            `yaml:"logFormat" default:"text"`
	LogPrivacy          bool                      `yaml:"logPrivacy" default:"false"`
	LogTimestamp        bool                      `yaml:"logTimestamp" default:"true"`
	DNSPorts            ListenConfig              `yaml:"port" default:"[\"53\"]"`
	HTTPPorts           ListenConfig              `yaml:"httpPort"`
	HTTPSPorts          ListenConfig              `yaml:"httpsPort"`
	TLSPorts            ListenConfig              `yaml:"tlsPort"`
	DoHUserAgent        string                    `yaml:"dohUserAgent"`
	MinTLSServeVer      string                    `yaml:"minTlsServeVersion" default:"1.2"`
	StartVerifyUpstream bool                      `yaml:"startVerifyUpstream" default:"false"`
	// Deprecated
	DisableIPv6  bool            `yaml:"disableIPv6" default:"false"`
	CertFile     string          `yaml:"certFile"`
	KeyFile      string          `yaml:"keyFile"`
	BootstrapDNS BootstrapConfig `yaml:"bootstrapDns"`
	HostsFile    HostsFileConfig `yaml:"hostsFile"`
	FqdnOnly     bool            `yaml:"fqdnOnly" default:"false"`
	Filtering    FilteringConfig `yaml:"filtering"`
	Ede          EdeConfig       `yaml:"ede"`
}

type BootstrapConfig bootstrapConfig // to avoid infinite recursion. See BootstrapConfig.UnmarshalYAML.
type bootstrapConfig struct {
	Upstream Upstream `yaml:"upstream"`
	IPs      []net.IP `yaml:"ips"`
}

// PrometheusConfig contains the config values for prometheus
type PrometheusConfig struct {
	Enable bool   `yaml:"enable" default:"false"`
	Path   string `yaml:"path" default:"/metrics"`
}

// UpstreamConfig upstream server configuration
type UpstreamConfig struct {
	ExternalResolvers map[string][]Upstream `yaml:",inline"`
}

// RewriteConfig custom DNS configuration
type RewriteConfig struct {
	Rewrite          map[string]string `yaml:"rewrite"`
	FallbackUpstream bool              `yaml:"fallbackUpstream" default:"false"`
}

// CustomDNSConfig custom DNS configuration
type CustomDNSConfig struct {
	RewriteConfig       `yaml:",inline"`
	CustomTTL           Duration         `yaml:"customTTL" default:"1h"`
	Mapping             CustomDNSMapping `yaml:"mapping"`
	FilterUnmappedTypes bool             `yaml:"filterUnmappedTypes" default:"true"`
}

// CustomDNSMapping mapping for the custom DNS configuration
type CustomDNSMapping struct {
	HostIPs map[string][]net.IP
}

// ConditionalUpstreamConfig conditional upstream configuration
type ConditionalUpstreamConfig struct {
	RewriteConfig `yaml:",inline"`
	Mapping       ConditionalUpstreamMapping `yaml:"mapping"`
}

// ConditionalUpstreamMapping mapping for conditional configuration
type ConditionalUpstreamMapping struct {
	Upstreams map[string][]Upstream
}

// BlockingConfig configuration for query blocking
type BlockingConfig struct {
	BlackLists        map[string][]string `yaml:"blackLists"`
	WhiteLists        map[string][]string `yaml:"whiteLists"`
	ClientGroupsBlock map[string][]string `yaml:"clientGroupsBlock"`
	BlockType         string              `yaml:"blockType" default:"ZEROIP"`
	BlockTTL          Duration            `yaml:"blockTTL" default:"6h"`
	DownloadTimeout   Duration            `yaml:"downloadTimeout" default:"60s"`
	DownloadAttempts  uint                `yaml:"downloadAttempts" default:"3"`
	DownloadCooldown  Duration            `yaml:"downloadCooldown" default:"1s"`
	RefreshPeriod     Duration            `yaml:"refreshPeriod" default:"4h"`
	// Deprecated
	FailStartOnListError  bool              `yaml:"failStartOnListError" default:"false"`
	ProcessingConcurrency uint              `yaml:"processingConcurrency" default:"4"`
	StartStrategy         StartStrategyType `yaml:"startStrategy" default:"blocking"`
}

// ClientLookupConfig configuration for the client lookup
type ClientLookupConfig struct {
	ClientnameIPMapping map[string][]net.IP `yaml:"clients"`
	Upstream            Upstream            `yaml:"upstream"`
	SingleNameOrder     []uint              `yaml:"singleNameOrder"`
}

// CachingConfig configuration for domain caching
type CachingConfig struct {
	MinCachingTime        Duration `yaml:"minTime"`
	MaxCachingTime        Duration `yaml:"maxTime"`
	CacheTimeNegative     Duration `yaml:"cacheTimeNegative" default:"30m"`
	MaxItemsCount         int      `yaml:"maxItemsCount"`
	Prefetching           bool     `yaml:"prefetching"`
	PrefetchExpires       Duration `yaml:"prefetchExpires" default:"2h"`
	PrefetchThreshold     int      `yaml:"prefetchThreshold" default:"5"`
	PrefetchMaxItemsCount int      `yaml:"prefetchMaxItemsCount"`
}

// QueryLogConfig configuration for the query logging
type QueryLogConfig struct {
	Target           string          `yaml:"target"`
	Type             QueryLogType    `yaml:"type"`
	LogRetentionDays uint64          `yaml:"logRetentionDays"`
	CreationAttempts int             `yaml:"creationAttempts" default:"3"`
	CreationCooldown Duration        `yaml:"creationCooldown" default:"2s"`
	Fields           []QueryLogField `yaml:"fields"`
}

// RedisConfig configuration for the redis connection
type RedisConfig struct {
	Address            string   `yaml:"address"`
	Username           string   `yaml:"username" default:""`
	Password           string   `yaml:"password" default:""`
	Database           int      `yaml:"database" default:"0"`
	Required           bool     `yaml:"required" default:"false"`
	ConnectionAttempts int      `yaml:"connectionAttempts" default:"3"`
	ConnectionCooldown Duration `yaml:"connectionCooldown" default:"1s"`
	SentinelUsername   string   `yaml:"sentinelUsername" default:""`
	SentinelPassword   string   `yaml:"sentinelPassword" default:""`
	SentinelAddresses  []string `yaml:"sentinelAddresses"`
}

type HostsFileConfig struct {
	Filepath       string   `yaml:"filePath"`
	HostsTTL       Duration `yaml:"hostsTTL" default:"1h"`
	RefreshPeriod  Duration `yaml:"refreshPeriod" default:"1h"`
	FilterLoopback bool     `yaml:"filterLoopback"`
}

type FilteringConfig struct {
	QueryTypes QTypeSet `yaml:"queryTypes"`
}

type EdeConfig struct {
	Enable bool `yaml:"enable" default:"false"`
}

//nolint:gochecknoglobals
var (
	config  = &Config{}
	cfgLock sync.RWMutex
)

// LoadConfig creates new config from YAML file or a directory containing YAML files
func LoadConfig(path string, mandatory bool) (*Config, error) {
	cfgLock.Lock()
	defer cfgLock.Unlock()

	cfg := Config{}
	if err := defaults.Set(&cfg); err != nil {
		return nil, fmt.Errorf("can't apply default values: %w", err)
	}

	fs, err := os.Stat(path)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) && !mandatory {
			// config file does not exist
			// return config with default values
			config = &cfg

			return config, nil
		}

		return nil, fmt.Errorf("can't read config file(s): %w", err)
	}

	var data []byte

	if fs.IsDir() {
		data, err = readFromDir(path, data)

		if err != nil {
			return nil, fmt.Errorf("can't read config files: %w", err)
		}
	} else {
		data, err = os.ReadFile(path)
		if err != nil {
			return nil, fmt.Errorf("can't read config file: %w", err)
		}
	}

	err = unmarshalConfig(data, &cfg)
	if err != nil {
		return nil, err
	}

	config = &cfg

	return &cfg, nil
}

func readFromDir(path string, data []byte) ([]byte, error) {
	err := filepath.WalkDir(path, func(filePath string, d os.DirEntry, err error) error {
		if err != nil {
			return err
		}

		if path == filePath {
			return nil
		}

		// Ignore non YAML files
		if !strings.HasSuffix(filePath, ".yml") && !strings.HasSuffix(filePath, ".yaml") {
			return nil
		}

		isRegular, err := isRegularFile(filePath)
		if err != nil {
			return err
		}

		// Ignore non regular files (directories, sockets, etc.)
		if !isRegular {
			return nil
		}

		fileData, err := os.ReadFile(filePath)
		if err != nil {
			return err
		}

		data = append(data, []byte("\n")...)
		data = append(data, fileData...)

		return nil
	})

	return data, err
}

// isRegularFile follows symlinks, so the result is `true` for a symlink to a regular file.
func isRegularFile(path string) (bool, error) {
	stat, err := os.Stat(path)
	if err != nil {
		return false, err
	}

	isRegular := stat.Mode()&os.ModeType == 0

	return isRegular, nil
}

func unmarshalConfig(data []byte, cfg *Config) error {
	err := yaml.UnmarshalStrict(data, cfg)
	if err != nil {
		return fmt.Errorf("wrong file structure: %w", err)
	}

	validateConfig(cfg)

	return nil
}

func validateConfig(cfg *Config) {
	if cfg.DisableIPv6 {
		log.Log().Warnf("'disableIPv6' is deprecated. Please use 'filtering.queryTypes' with 'AAAA' instead.")

		cfg.Filtering.QueryTypes.Insert(dns.Type(dns.TypeAAAA))
	}

	if cfg.Blocking.FailStartOnListError {
		log.Log().Warnf("'blocking.failStartOnListError' is deprecated. Please use 'blocking.startStrategy'" +
			" with 'failOnError' instead.")

		if cfg.Blocking.StartStrategy == StartStrategyTypeBlocking {
			cfg.Blocking.StartStrategy = StartStrategyTypeFailOnError
		} else if cfg.Blocking.StartStrategy == StartStrategyTypeFast {
			log.Log().Warnf("'blocking.startStrategy' with 'fast' will ignore 'blocking.failStartOnListError'.")
		}
	}
}

// GetConfig returns the current config
func GetConfig() *Config {
	cfgLock.RLock()
	defer cfgLock.RUnlock()

	return config
}

// ConvertPort converts string representation into a valid port (0 - 65535)
func ConvertPort(in string) (uint16, error) {
	const (
		base    = 10
		bitSize = 16
	)

	var p uint64
	p, err := strconv.ParseUint(strings.TrimSpace(in), base, bitSize)

	if err != nil {
		return 0, err
	}

	return uint16(p), nil
}