package dnsforward import ( "crypto/tls" "crypto/x509" "fmt" "net" "net/netip" "os" "strings" "time" "github.com/AdguardTeam/AdGuardHome/internal/aghalg" "github.com/AdguardTeam/AdGuardHome/internal/aghhttp" "github.com/AdguardTeam/AdGuardHome/internal/aghnet" "github.com/AdguardTeam/AdGuardHome/internal/aghtls" "github.com/AdguardTeam/AdGuardHome/internal/client" "github.com/AdguardTeam/AdGuardHome/internal/filtering" "github.com/AdguardTeam/dnsproxy/proxy" "github.com/AdguardTeam/dnsproxy/upstream" "github.com/AdguardTeam/golibs/errors" "github.com/AdguardTeam/golibs/log" "github.com/AdguardTeam/golibs/netutil" "github.com/AdguardTeam/golibs/stringutil" "github.com/AdguardTeam/golibs/timeutil" "github.com/ameshkov/dnscrypt/v2" "golang.org/x/exp/slices" ) // ClientsContainer provides information about preconfigured DNS clients. type ClientsContainer interface { // UpstreamConfigByID returns the custom upstream configuration for the // client having id, using boot to initialize the one if necessary. It // returns nil if there is no custom upstream configuration for the client. // The id is expected to be either a string representation of an IP address // or the ClientID. UpstreamConfigByID( id string, boot upstream.Resolver, ) (conf *proxy.CustomUpstreamConfig, err error) } // Config represents the DNS filtering configuration of AdGuard Home. The zero // Config is empty and ready for use. type Config struct { // Callbacks for other modules // FilterHandler is an optional additional filtering callback. FilterHandler func(cliAddr netip.Addr, clientID string, settings *filtering.Settings) `yaml:"-"` // ClientsContainer stores the information about special handling of some // DNS clients. ClientsContainer ClientsContainer `yaml:"-"` // Anti-DNS amplification // Ratelimit is the maximum number of requests per second from a given IP // (0 to disable). Ratelimit uint32 `yaml:"ratelimit"` // RatelimitSubnetLenIPv4 is a subnet length for IPv4 addresses used for // rate limiting requests. RatelimitSubnetLenIPv4 int `yaml:"ratelimit_subnet_len_ipv4"` // RatelimitSubnetLenIPv6 is a subnet length for IPv6 addresses used for // rate limiting requests. RatelimitSubnetLenIPv6 int `yaml:"ratelimit_subnet_len_ipv6"` // RatelimitWhitelist is the list of whitelisted client IP addresses. RatelimitWhitelist []netip.Addr `yaml:"ratelimit_whitelist"` // RefuseAny, if true, refuse ANY requests. RefuseAny bool `yaml:"refuse_any"` // Upstream DNS servers configuration // UpstreamDNS is the list of upstream DNS servers. UpstreamDNS []string `yaml:"upstream_dns"` // UpstreamDNSFileName, if set, points to the file which contains upstream // DNS servers. UpstreamDNSFileName string `yaml:"upstream_dns_file"` // BootstrapDNS is the list of bootstrap DNS servers for DoH and DoT // resolvers (plain DNS only). BootstrapDNS []string `yaml:"bootstrap_dns"` // FallbackDNS is the list of fallback DNS servers used when upstream DNS // servers are not responding. FallbackDNS []string `yaml:"fallback_dns"` // UpstreamMode determines the logic through which upstreams will be used. UpstreamMode UpstreamMode `yaml:"upstream_mode"` // FastestTimeout replaces the default timeout for dialing IP addresses // when FastestAddr is true. FastestTimeout timeutil.Duration `yaml:"fastest_timeout"` // Access settings // AllowedClients is the slice of IP addresses, CIDR networks, and // ClientIDs of allowed clients. If not empty, only these clients are // allowed, and [Config.DisallowedClients] are ignored. AllowedClients []string `yaml:"allowed_clients"` // DisallowedClients is the slice of IP addresses, CIDR networks, and // ClientIDs of disallowed clients. DisallowedClients []string `yaml:"disallowed_clients"` // BlockedHosts is the list of hosts that should be blocked. BlockedHosts []string `yaml:"blocked_hosts"` // TrustedProxies is the list of CIDR networks with proxy servers addresses // from which the DoH requests should be handled. The value of nil or an // empty slice for this field makes Proxy not trust any address. TrustedProxies []netutil.Prefix `yaml:"trusted_proxies"` // DNS cache settings // CacheSize is the DNS cache size (in bytes). CacheSize uint32 `yaml:"cache_size"` // CacheMinTTL is the override TTL value (minimum) received from upstream // server. CacheMinTTL uint32 `yaml:"cache_ttl_min"` // CacheMaxTTL is the override TTL value (maximum) received from upstream // server. CacheMaxTTL uint32 `yaml:"cache_ttl_max"` // CacheOptimistic defines if optimistic cache mechanism should be used. CacheOptimistic bool `yaml:"cache_optimistic"` // Other settings // BogusNXDomain is the list of IP addresses, responses with them will be // transformed to NXDOMAIN. BogusNXDomain []string `yaml:"bogus_nxdomain"` // AAAADisabled, if true, respond with an empty answer to all AAAA // requests. AAAADisabled bool `yaml:"aaaa_disabled"` // EnableDNSSEC, if true, set AD flag in outcoming DNS request. EnableDNSSEC bool `yaml:"enable_dnssec"` // EDNSClientSubnet is the settings list for EDNS Client Subnet. EDNSClientSubnet *EDNSClientSubnet `yaml:"edns_client_subnet"` // MaxGoroutines is the max number of parallel goroutines for processing // incoming requests. MaxGoroutines uint `yaml:"max_goroutines"` // HandleDDR, if true, handle DDR requests HandleDDR bool `yaml:"handle_ddr"` // IpsetList is the ipset configuration that allows AdGuard Home to add IP // addresses of the specified domain names to an ipset list. Syntax: // // DOMAIN[,DOMAIN].../IPSET_NAME // // This field is ignored if [IpsetListFileName] is set. IpsetList []string `yaml:"ipset"` // IpsetListFileName, if set, points to the file with ipset configuration. // The format is the same as in [IpsetList]. IpsetListFileName string `yaml:"ipset_file"` // BootstrapPreferIPv6, if true, instructs the bootstrapper to prefer IPv6 // addresses to IPv4 ones for DoH, DoQ, and DoT. BootstrapPreferIPv6 bool `yaml:"bootstrap_prefer_ipv6"` } // EDNSClientSubnet is the settings list for EDNS Client Subnet. type EDNSClientSubnet struct { // CustomIP for EDNS Client Subnet. CustomIP netip.Addr `yaml:"custom_ip"` // Enabled defines if EDNS Client Subnet is enabled. Enabled bool `yaml:"enabled"` // UseCustom defines if CustomIP should be used. UseCustom bool `yaml:"use_custom"` } // TLSConfig is the TLS configuration for HTTPS, DNS-over-HTTPS, and DNS-over-TLS type TLSConfig struct { cert tls.Certificate TLSListenAddrs []*net.TCPAddr `yaml:"-" json:"-"` QUICListenAddrs []*net.UDPAddr `yaml:"-" json:"-"` HTTPSListenAddrs []*net.TCPAddr `yaml:"-" json:"-"` // PEM-encoded certificates chain CertificateChain string `yaml:"certificate_chain" json:"certificate_chain"` // PEM-encoded private key PrivateKey string `yaml:"private_key" json:"private_key"` CertificatePath string `yaml:"certificate_path" json:"certificate_path"` PrivateKeyPath string `yaml:"private_key_path" json:"private_key_path"` CertificateChainData []byte `yaml:"-" json:"-"` PrivateKeyData []byte `yaml:"-" json:"-"` // ServerName is the hostname of the server. Currently, it is only being // used for ClientID checking and Discovery of Designated Resolvers (DDR). ServerName string `yaml:"-" json:"-"` // DNS names from certificate (SAN) or CN value from Subject dnsNames []string // OverrideTLSCiphers, when set, contains the names of the cipher suites to // use. If the slice is empty, the default safe suites are used. OverrideTLSCiphers []string `yaml:"override_tls_ciphers,omitempty" json:"-"` // StrictSNICheck controls if the connections with SNI mismatching the // certificate's ones should be rejected. StrictSNICheck bool `yaml:"strict_sni_check" json:"-"` // hasIPAddrs is set during the certificate parsing and is true if the // configured certificate contains at least a single IP address. hasIPAddrs bool } // DNSCryptConfig is the DNSCrypt server configuration struct. type DNSCryptConfig struct { ResolverCert *dnscrypt.Cert ProviderName string UDPListenAddrs []*net.UDPAddr TCPListenAddrs []*net.TCPAddr Enabled bool } // ServerConfig represents server configuration. // The zero ServerConfig is empty and ready for use. type ServerConfig struct { UDPListenAddrs []*net.UDPAddr // UDP listen address TCPListenAddrs []*net.TCPAddr // TCP listen address UpstreamConfig *proxy.UpstreamConfig // Upstream DNS servers config // AddrProcConf defines the configuration for the client IP processor. // If nil, [client.EmptyAddrProc] is used. // // TODO(a.garipov): The use of [client.EmptyAddrProc] is a crutch for tests. // Remove that. AddrProcConf *client.DefaultAddrProcConfig Config TLSConfig DNSCryptConfig TLSAllowUnencryptedDoH bool // UpstreamTimeout is the timeout for querying upstream servers. UpstreamTimeout time.Duration TLSv12Roots *x509.CertPool // list of root CAs for TLSv1.2 // TLSCiphers are the IDs of TLS cipher suites to use. TLSCiphers []uint16 // Called when the configuration is changed by HTTP request ConfigModified func() // Register an HTTP handler HTTPRegister aghhttp.RegisterFunc // LocalPTRResolvers is a slice of addresses to be used as upstreams for // resolving PTR queries for local addresses. LocalPTRResolvers []string // DNS64Prefixes is a slice of NAT64 prefixes to be used for DNS64. DNS64Prefixes []netip.Prefix // UsePrivateRDNS defines if the PTR requests for unknown addresses from // locally-served networks should be resolved via private PTR resolvers. UsePrivateRDNS bool // UseDNS64 defines if DNS64 is enabled for incoming requests. UseDNS64 bool // ServeHTTP3 defines if HTTP/3 is be allowed for incoming requests. ServeHTTP3 bool // UseHTTP3Upstreams defines if HTTP/3 is be allowed for DNS-over-HTTPS // upstreams. UseHTTP3Upstreams bool // ServePlainDNS defines if plain DNS is allowed for incoming requests. ServePlainDNS bool } // UpstreamMode is a enumeration of upstream mode representations. See // [proxy.UpstreamModeType]. type UpstreamMode string const ( UpstreamModeLoadBalance UpstreamMode = "load_balance" UpstreamModeParallel UpstreamMode = "parallel" UpstreamModeFastestAddr UpstreamMode = "fastest_addr" ) // newProxyConfig creates and validates configuration for the main proxy. func (s *Server) newProxyConfig() (conf *proxy.Config, err error) { srvConf := s.conf trustedPrefixes := netutil.UnembedPrefixes(srvConf.TrustedProxies) conf = &proxy.Config{ HTTP3: srvConf.ServeHTTP3, Ratelimit: int(srvConf.Ratelimit), RatelimitSubnetLenIPv4: srvConf.RatelimitSubnetLenIPv4, RatelimitSubnetLenIPv6: srvConf.RatelimitSubnetLenIPv6, RatelimitWhitelist: srvConf.RatelimitWhitelist, RefuseAny: srvConf.RefuseAny, TrustedProxies: netutil.SliceSubnetSet(trustedPrefixes), CacheMinTTL: srvConf.CacheMinTTL, CacheMaxTTL: srvConf.CacheMaxTTL, CacheOptimistic: srvConf.CacheOptimistic, UpstreamConfig: srvConf.UpstreamConfig, BeforeRequestHandler: s.beforeRequestHandler, RequestHandler: s.handleDNSRequest, HTTPSServerName: aghhttp.UserAgent(), EnableEDNSClientSubnet: srvConf.EDNSClientSubnet.Enabled, MaxGoroutines: srvConf.MaxGoroutines, UseDNS64: srvConf.UseDNS64, DNS64Prefs: srvConf.DNS64Prefixes, } if srvConf.EDNSClientSubnet.UseCustom { // TODO(s.chzhen): Use netip.Addr instead of net.IP inside dnsproxy. conf.EDNSAddr = net.IP(srvConf.EDNSClientSubnet.CustomIP.AsSlice()) } err = setProxyUpstreamMode(conf, srvConf.UpstreamMode, srvConf.FastestTimeout.Duration) if err != nil { return nil, fmt.Errorf("upstream mode: %w", err) } conf.BogusNXDomain, err = parseBogusNXDOMAIN(srvConf.BogusNXDomain) if err != nil { return nil, fmt.Errorf("bogus_nxdomain: %w", err) } err = s.prepareTLS(conf) if err != nil { return nil, fmt.Errorf("validating tls: %w", err) } err = s.preparePlain(conf) if err != nil { return nil, fmt.Errorf("validating plain: %w", err) } if c := srvConf.DNSCryptConfig; c.Enabled { conf.DNSCryptUDPListenAddr = c.UDPListenAddrs conf.DNSCryptTCPListenAddr = c.TCPListenAddrs conf.DNSCryptProviderName = c.ProviderName conf.DNSCryptResolverCert = c.ResolverCert } if conf.UpstreamConfig == nil || len(conf.UpstreamConfig.Upstreams) == 0 { return nil, errors.Error("no default upstream servers configured") } conf, err = prepareCacheConfig(conf, srvConf.CacheSize, srvConf.CacheMinTTL, srvConf.CacheMaxTTL, ) if err != nil { // Don't wrap the error since it's informative enough as is. return nil, err } return conf, nil } // prepareCacheConfig prepares the cache configuration and returns an error if // there is one. func prepareCacheConfig( conf *proxy.Config, size uint32, minTTL uint32, maxTTL uint32, ) (prepared *proxy.Config, err error) { if size != 0 { conf.CacheEnabled = true conf.CacheSizeBytes = int(size) } err = validateCacheTTL(minTTL, maxTTL) if err != nil { return nil, fmt.Errorf("validating cache ttl: %w", err) } return conf, nil } // parseBogusNXDOMAIN parses the bogus NXDOMAIN strings into valid subnets. func parseBogusNXDOMAIN(confBogusNXDOMAIN []string) (subnets []netip.Prefix, err error) { for i, s := range confBogusNXDOMAIN { var subnet netip.Prefix subnet, err = aghnet.ParseSubnet(s) if err != nil { return nil, fmt.Errorf("subnet at index %d: %w", i, err) } subnets = append(subnets, subnet) } return subnets, nil } const defaultBlockedResponseTTL = 3600 // initDefaultSettings initializes default settings if nothing // is configured func (s *Server) initDefaultSettings() { if len(s.conf.UpstreamDNS) == 0 { s.conf.UpstreamDNS = defaultDNS } if len(s.conf.BootstrapDNS) == 0 { s.conf.BootstrapDNS = defaultBootstrap } if s.conf.UDPListenAddrs == nil { s.conf.UDPListenAddrs = defaultUDPListenAddrs } if s.conf.TCPListenAddrs == nil { s.conf.TCPListenAddrs = defaultTCPListenAddrs } if len(s.conf.BlockedHosts) == 0 { s.conf.BlockedHosts = defaultBlockedHosts } if s.conf.UpstreamTimeout == 0 { s.conf.UpstreamTimeout = DefaultTimeout } } // prepareIpsetListSettings reads and prepares the ipset configuration either // from a file or from the data in the configuration file. func (s *Server) prepareIpsetListSettings() (err error) { fn := s.conf.IpsetListFileName if fn == "" { return s.ipset.init(s.conf.IpsetList) } // #nosec G304 -- Trust the path explicitly given by the user. data, err := os.ReadFile(fn) if err != nil { return err } ipsets := stringutil.SplitTrimmed(string(data), "\n") log.Debug("dns: using %d ipset rules from file %q", len(ipsets), fn) return s.ipset.init(ipsets) } // collectListenAddr adds addrPort to addrs. It also adds its port to // unspecPorts if its address is unspecified. func collectListenAddr( addrPort netip.AddrPort, addrs map[netip.AddrPort]unit, unspecPorts map[uint16]unit, ) { if addrPort == (netip.AddrPort{}) { return } addrs[addrPort] = unit{} if addrPort.Addr().IsUnspecified() { unspecPorts[addrPort.Port()] = unit{} } } // collectDNSAddrs returns configured set of listening addresses. It also // returns a set of ports of each unspecified listening address. func (conf *ServerConfig) collectDNSAddrs() (addrs mapAddrPortSet, unspecPorts map[uint16]unit) { // TODO(e.burkov): Perhaps, we shouldn't allocate as much memory, since the // TCP and UDP listening addresses are currently the same. addrs = make(map[netip.AddrPort]unit, len(conf.TCPListenAddrs)+len(conf.UDPListenAddrs)) unspecPorts = map[uint16]unit{} for _, laddr := range conf.TCPListenAddrs { collectListenAddr(laddr.AddrPort(), addrs, unspecPorts) } for _, laddr := range conf.UDPListenAddrs { collectListenAddr(laddr.AddrPort(), addrs, unspecPorts) } return addrs, unspecPorts } // defaultPlainDNSPort is the default port for plain DNS. const defaultPlainDNSPort uint16 = 53 // addrPortSet is a set of [netip.AddrPort] values. type addrPortSet interface { // Has returns true if addrPort is in the set. Has(addrPort netip.AddrPort) (ok bool) } // type check var _ addrPortSet = emptyAddrPortSet{} // emptyAddrPortSet is the [addrPortSet] containing no values. type emptyAddrPortSet struct{} // Has implements the [addrPortSet] interface for [emptyAddrPortSet]. func (emptyAddrPortSet) Has(_ netip.AddrPort) (ok bool) { return false } // mapAddrPortSet is the [addrPortSet] containing values of [netip.AddrPort] as // keys of a map. type mapAddrPortSet map[netip.AddrPort]unit // type check var _ addrPortSet = mapAddrPortSet{} // Has implements the [addrPortSet] interface for [mapAddrPortSet]. func (m mapAddrPortSet) Has(addrPort netip.AddrPort) (ok bool) { _, ok = m[addrPort] return ok } // combinedAddrPortSet is the [addrPortSet] defined by some IP addresses along // with ports, any combination of which is considered being in the set. type combinedAddrPortSet struct { // TODO(e.burkov): Use sorted slices in combination with binary search. ports map[uint16]unit addrs []netip.Addr } // type check var _ addrPortSet = (*combinedAddrPortSet)(nil) // Has implements the [addrPortSet] interface for [*combinedAddrPortSet]. func (m *combinedAddrPortSet) Has(addrPort netip.AddrPort) (ok bool) { _, ok = m.ports[addrPort.Port()] return ok && slices.Contains(m.addrs, addrPort.Addr()) } // filterOut filters out all the upstreams that match um. It returns all the // closing errors joined. func filterOutAddrs(upsConf *proxy.UpstreamConfig, set addrPortSet) (err error) { var errs []error delFunc := func(u upstream.Upstream) (ok bool) { // TODO(e.burkov): We should probably consider the protocol of u to // only filter out the listening addresses of the same protocol. addr, parseErr := aghnet.ParseAddrPort(u.Address(), defaultPlainDNSPort) if parseErr != nil || !set.Has(addr) { // Don't filter out the upstream if it either cannot be parsed, or // does not match m. return false } errs = append(errs, u.Close()) return true } upsConf.Upstreams = slices.DeleteFunc(upsConf.Upstreams, delFunc) for d, ups := range upsConf.DomainReservedUpstreams { upsConf.DomainReservedUpstreams[d] = slices.DeleteFunc(ups, delFunc) } for d, ups := range upsConf.SpecifiedDomainUpstreams { upsConf.SpecifiedDomainUpstreams[d] = slices.DeleteFunc(ups, delFunc) } return errors.Join(errs...) } // ourAddrsSet returns an addrPortSet that contains all the configured listening // addresses. func (conf *ServerConfig) ourAddrsSet() (m addrPortSet, err error) { addrs, unspecPorts := conf.collectDNSAddrs() switch { case len(addrs) == 0: log.Debug("dnsforward: no listen addresses") return emptyAddrPortSet{}, nil case len(unspecPorts) == 0: log.Debug("dnsforward: filtering out addresses %s", addrs) return addrs, nil default: var ifaceAddrs []netip.Addr ifaceAddrs, err = aghnet.CollectAllIfacesAddrs() if err != nil { // Don't wrap the error since it's informative enough as is. return nil, err } log.Debug("dnsforward: filtering out addresses %s on ports %d", ifaceAddrs, unspecPorts) return &combinedAddrPortSet{ ports: unspecPorts, addrs: ifaceAddrs, }, nil } } // prepareTLS - prepares TLS configuration for the DNS proxy func (s *Server) prepareTLS(proxyConfig *proxy.Config) (err error) { if len(s.conf.CertificateChainData) == 0 || len(s.conf.PrivateKeyData) == 0 { return nil } if s.conf.TLSListenAddrs == nil && s.conf.QUICListenAddrs == nil { return nil } proxyConfig.TLSListenAddr = aghalg.CoalesceSlice( s.conf.TLSListenAddrs, proxyConfig.TLSListenAddr, ) proxyConfig.QUICListenAddr = aghalg.CoalesceSlice( s.conf.QUICListenAddrs, proxyConfig.QUICListenAddr, ) s.conf.cert, err = tls.X509KeyPair(s.conf.CertificateChainData, s.conf.PrivateKeyData) if err != nil { return fmt.Errorf("failed to parse TLS keypair: %w", err) } cert, err := x509.ParseCertificate(s.conf.cert.Certificate[0]) if err != nil { return fmt.Errorf("x509.ParseCertificate(): %w", err) } s.conf.hasIPAddrs = aghtls.CertificateHasIP(cert) if s.conf.StrictSNICheck { if len(cert.DNSNames) != 0 { s.conf.dnsNames = cert.DNSNames log.Debug("dns: using certificate's SAN as DNS names: %v", cert.DNSNames) slices.Sort(s.conf.dnsNames) } else { s.conf.dnsNames = append(s.conf.dnsNames, cert.Subject.CommonName) log.Debug("dns: using certificate's CN as DNS name: %s", cert.Subject.CommonName) } } proxyConfig.TLSConfig = &tls.Config{ GetCertificate: s.onGetCertificate, CipherSuites: s.conf.TLSCiphers, MinVersion: tls.VersionTLS12, } return nil } // isWildcard returns true if host is a wildcard hostname. func isWildcard(host string) (ok bool) { return strings.HasPrefix(host, "*.") } // matchesDomainWildcard returns true if host matches the domain wildcard // pattern pat. func matchesDomainWildcard(host, pat string) (ok bool) { return isWildcard(pat) && strings.HasSuffix(host, pat[1:]) } // anyNameMatches returns true if sni, the client's SNI value, matches any of // the DNS names and patterns from certificate. dnsNames must be sorted. func anyNameMatches(dnsNames []string, sni string) (ok bool) { // Check sni is either a valid hostname or a valid IP address. if netutil.ValidateHostname(sni) != nil && net.ParseIP(sni) == nil { return false } if _, ok = slices.BinarySearch(dnsNames, sni); ok { return true } for _, dn := range dnsNames { if matchesDomainWildcard(sni, dn) { return true } } return false } // Called by 'tls' package when Client Hello is received // If the server name (from SNI) supplied by client is incorrect - we terminate the ongoing TLS handshake. func (s *Server) onGetCertificate(ch *tls.ClientHelloInfo) (*tls.Certificate, error) { if s.conf.StrictSNICheck && !anyNameMatches(s.conf.dnsNames, ch.ServerName) { log.Info("dns: tls: unknown SNI in Client Hello: %s", ch.ServerName) return nil, fmt.Errorf("invalid SNI") } return &s.conf.cert, nil } // preparePlain prepares the plain-DNS configuration for the DNS proxy. // preparePlain assumes that prepareTLS has already been called. func (s *Server) preparePlain(proxyConf *proxy.Config) (err error) { if s.conf.ServePlainDNS { proxyConf.UDPListenAddr = s.conf.UDPListenAddrs proxyConf.TCPListenAddr = s.conf.TCPListenAddrs return nil } lenEncrypted := len(proxyConf.DNSCryptTCPListenAddr) + len(proxyConf.DNSCryptUDPListenAddr) + len(proxyConf.HTTPSListenAddr) + len(proxyConf.QUICListenAddr) + len(proxyConf.TLSListenAddr) if lenEncrypted == 0 { // TODO(a.garipov): Support full disabling of all DNS. return errors.Error("disabling plain dns requires at least one encrypted protocol") } log.Info("dnsforward: warning: plain dns is disabled") return nil } // UpdatedProtectionStatus updates protection state, if the protection was // disabled temporarily. Returns the updated state of protection. func (s *Server) UpdatedProtectionStatus() (enabled bool, disabledUntil *time.Time) { s.serverLock.RLock() defer s.serverLock.RUnlock() enabled, disabledUntil = s.dnsFilter.ProtectionStatus() if disabledUntil == nil { return enabled, nil } if time.Now().Before(*disabledUntil) { return false, disabledUntil } // Update the values in a separate goroutine, unless an update is already in // progress. Since this method is called very often, and this update is a // relatively rare situation, do not lock s.serverLock for writing, as that // can lead to freezes. // // See https://github.com/AdguardTeam/AdGuardHome/issues/5661. if s.protectionUpdateInProgress.CompareAndSwap(false, true) { go s.enableProtectionAfterPause() } return true, nil } // enableProtectionAfterPause sets the protection configuration to enabled // values. It is intended to be used as a goroutine. func (s *Server) enableProtectionAfterPause() { defer log.OnPanic("dns: enabling protection after pause") defer s.protectionUpdateInProgress.Store(false) defer s.conf.ConfigModified() s.serverLock.Lock() defer s.serverLock.Unlock() s.dnsFilter.SetProtectionStatus(true, nil) log.Info("dns: protection is restarted after pause") } // validateCacheTTL returns an error if the configuration of the cache TTL // invalid. // // TODO(s.chzhen): Move to dnsproxy. func validateCacheTTL(minTTL, maxTTL uint32) (err error) { if minTTL == 0 && maxTTL == 0 { return nil } if maxTTL > 0 && minTTL > maxTTL { return errors.Error("cache_ttl_min must be less than or equal to cache_ttl_max") } return nil }