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dns.go
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dns.go
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package home
import (
"fmt"
"net"
"net/netip"
"net/url"
"os"
"path/filepath"
"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
"github.com/AdguardTeam/AdGuardHome/internal/dnsforward"
"github.com/AdguardTeam/AdGuardHome/internal/filtering"
"github.com/AdguardTeam/AdGuardHome/internal/querylog"
"github.com/AdguardTeam/AdGuardHome/internal/stats"
"github.com/AdguardTeam/dnsproxy/proxy"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
"github.com/AdguardTeam/golibs/netutil"
"github.com/ameshkov/dnscrypt/v2"
yaml "gopkg.in/yaml.v3"
)
// Default ports.
const (
defaultPortDNS = 53
defaultPortHTTP = 80
defaultPortHTTPS = 443
defaultPortQUIC = 853
defaultPortTLS = 853
)
// Called by other modules when configuration is changed
func onConfigModified() {
err := config.write()
if err != nil {
log.Error("writing config: %s", err)
}
}
// initDNSServer creates an instance of the dnsforward.Server
// Please note that we must do it even if we don't start it
// so that we had access to the query log and the stats
func initDNSServer() (err error) {
baseDir := Context.getDataDir()
var anonFunc aghnet.IPMutFunc
if config.DNS.AnonymizeClientIP {
anonFunc = querylog.AnonymizeIP
}
anonymizer := aghnet.NewIPMut(anonFunc)
statsConf := stats.Config{
Filename: filepath.Join(baseDir, "stats.db"),
LimitDays: config.DNS.StatsInterval,
ConfigModified: onConfigModified,
HTTPRegister: httpRegister,
}
Context.stats, err = stats.New(statsConf)
if err != nil {
return fmt.Errorf("init stats: %w", err)
}
conf := querylog.Config{
Anonymizer: anonymizer,
ConfigModified: onConfigModified,
HTTPRegister: httpRegister,
FindClient: Context.clients.findMultiple,
BaseDir: baseDir,
RotationIvl: config.DNS.QueryLogInterval.Duration,
MemSize: config.DNS.QueryLogMemSize,
Enabled: config.DNS.QueryLogEnabled,
FileEnabled: config.DNS.QueryLogFileEnabled,
AnonymizeClientIP: config.DNS.AnonymizeClientIP,
}
Context.queryLog = querylog.New(conf)
Context.filters, err = filtering.New(config.DNS.DnsfilterConf, nil)
if err != nil {
// Don't wrap the error, since it's informative enough as is.
return err
}
var privateNets netutil.SubnetSet
switch len(config.DNS.PrivateNets) {
case 0:
// Use an optimized locally-served matcher.
privateNets = netutil.SubnetSetFunc(netutil.IsLocallyServed)
case 1:
privateNets, err = netutil.ParseSubnet(config.DNS.PrivateNets[0])
if err != nil {
return fmt.Errorf("preparing the set of private subnets: %w", err)
}
default:
var nets []*net.IPNet
nets, err = netutil.ParseSubnets(config.DNS.PrivateNets...)
if err != nil {
return fmt.Errorf("preparing the set of private subnets: %w", err)
}
privateNets = netutil.SliceSubnetSet(nets)
}
p := dnsforward.DNSCreateParams{
DNSFilter: Context.filters,
Stats: Context.stats,
QueryLog: Context.queryLog,
PrivateNets: privateNets,
Anonymizer: anonymizer,
LocalDomain: config.DHCP.LocalDomainName,
DHCPServer: Context.dhcpServer,
}
Context.dnsServer, err = dnsforward.NewServer(p)
if err != nil {
closeDNSServer()
return fmt.Errorf("dnsforward.NewServer: %w", err)
}
Context.clients.dnsServer = Context.dnsServer
var dnsConfig dnsforward.ServerConfig
dnsConfig, err = generateServerConfig()
if err != nil {
closeDNSServer()
return fmt.Errorf("generateServerConfig: %w", err)
}
err = Context.dnsServer.Prepare(&dnsConfig)
if err != nil {
closeDNSServer()
return fmt.Errorf("dnsServer.Prepare: %w", err)
}
if config.Clients.Sources.RDNS {
Context.rdns = NewRDNS(Context.dnsServer, &Context.clients, config.DNS.UsePrivateRDNS)
}
if config.Clients.Sources.WHOIS {
Context.whois = initWHOIS(&Context.clients)
}
return nil
}
func isRunning() bool {
return Context.dnsServer != nil && Context.dnsServer.IsRunning()
}
func onDNSRequest(pctx *proxy.DNSContext) {
ip, _ := netutil.IPAndPortFromAddr(pctx.Addr)
if ip == nil {
// This would be quite weird if we get here.
return
}
srcs := config.Clients.Sources
if srcs.RDNS && !ip.IsLoopback() {
Context.rdns.Begin(ip)
}
if srcs.WHOIS && !netutil.IsSpecialPurpose(ip) {
Context.whois.Begin(ip)
}
}
func ipsToTCPAddrs(ips []netip.Addr, port int) (tcpAddrs []*net.TCPAddr) {
if ips == nil {
return nil
}
tcpAddrs = make([]*net.TCPAddr, 0, len(ips))
for _, ip := range ips {
tcpAddrs = append(tcpAddrs, net.TCPAddrFromAddrPort(netip.AddrPortFrom(ip, uint16(port))))
}
return tcpAddrs
}
func ipsToUDPAddrs(ips []netip.Addr, port int) (udpAddrs []*net.UDPAddr) {
if ips == nil {
return nil
}
udpAddrs = make([]*net.UDPAddr, 0, len(ips))
for _, ip := range ips {
udpAddrs = append(udpAddrs, net.UDPAddrFromAddrPort(netip.AddrPortFrom(ip, uint16(port))))
}
return udpAddrs
}
func generateServerConfig() (newConf dnsforward.ServerConfig, err error) {
dnsConf := config.DNS
hosts := dnsConf.BindHosts
if len(hosts) == 0 {
hosts = []netip.Addr{aghnet.IPv4Localhost()}
}
newConf = dnsforward.ServerConfig{
UDPListenAddrs: ipsToUDPAddrs(hosts, dnsConf.Port),
TCPListenAddrs: ipsToTCPAddrs(hosts, dnsConf.Port),
FilteringConfig: dnsConf.FilteringConfig,
ConfigModified: onConfigModified,
HTTPRegister: httpRegister,
OnDNSRequest: onDNSRequest,
}
tlsConf := tlsConfigSettings{}
Context.tls.WriteDiskConfig(&tlsConf)
if tlsConf.Enabled {
newConf.TLSConfig = tlsConf.TLSConfig
newConf.TLSConfig.ServerName = tlsConf.ServerName
if tlsConf.PortHTTPS != 0 {
newConf.HTTPSListenAddrs = ipsToTCPAddrs(hosts, tlsConf.PortHTTPS)
}
if tlsConf.PortDNSOverTLS != 0 {
newConf.TLSListenAddrs = ipsToTCPAddrs(hosts, tlsConf.PortDNSOverTLS)
}
if tlsConf.PortDNSOverQUIC != 0 {
newConf.QUICListenAddrs = ipsToUDPAddrs(hosts, tlsConf.PortDNSOverQUIC)
}
if tlsConf.PortDNSCrypt != 0 {
newConf.DNSCryptConfig, err = newDNSCrypt(hosts, tlsConf)
if err != nil {
// Don't wrap the error, because it's already
// wrapped by newDNSCrypt.
return dnsforward.ServerConfig{}, err
}
}
}
newConf.TLSv12Roots = Context.tlsRoots
newConf.TLSAllowUnencryptedDoH = tlsConf.AllowUnencryptedDoH
newConf.FilterHandler = applyAdditionalFiltering
newConf.GetCustomUpstreamByClient = Context.clients.findUpstreams
newConf.LocalPTRResolvers = dnsConf.LocalPTRResolvers
newConf.UpstreamTimeout = dnsConf.UpstreamTimeout.Duration
newConf.ResolveClients = config.Clients.Sources.RDNS
newConf.UsePrivateRDNS = dnsConf.UsePrivateRDNS
newConf.ServeHTTP3 = dnsConf.ServeHTTP3
newConf.UseHTTP3Upstreams = dnsConf.UseHTTP3Upstreams
return newConf, nil
}
func newDNSCrypt(hosts []netip.Addr, tlsConf tlsConfigSettings) (dnscc dnsforward.DNSCryptConfig, err error) {
if tlsConf.DNSCryptConfigFile == "" {
return dnscc, errors.Error("no dnscrypt_config_file")
}
f, err := os.Open(tlsConf.DNSCryptConfigFile)
if err != nil {
return dnscc, fmt.Errorf("opening dnscrypt config: %w", err)
}
defer func() { err = errors.WithDeferred(err, f.Close()) }()
rc := &dnscrypt.ResolverConfig{}
err = yaml.NewDecoder(f).Decode(rc)
if err != nil {
return dnscc, fmt.Errorf("decoding dnscrypt config: %w", err)
}
cert, err := rc.CreateCert()
if err != nil {
return dnscc, fmt.Errorf("creating dnscrypt cert: %w", err)
}
return dnsforward.DNSCryptConfig{
ResolverCert: cert,
ProviderName: rc.ProviderName,
UDPListenAddrs: ipsToUDPAddrs(hosts, tlsConf.PortDNSCrypt),
TCPListenAddrs: ipsToTCPAddrs(hosts, tlsConf.PortDNSCrypt),
Enabled: true,
}, nil
}
type dnsEncryption struct {
https string
tls string
quic string
}
func getDNSEncryption() (de dnsEncryption) {
tlsConf := tlsConfigSettings{}
Context.tls.WriteDiskConfig(&tlsConf)
if tlsConf.Enabled && len(tlsConf.ServerName) != 0 {
hostname := tlsConf.ServerName
if tlsConf.PortHTTPS != 0 {
addr := hostname
if tlsConf.PortHTTPS != defaultPortHTTPS {
addr = netutil.JoinHostPort(addr, tlsConf.PortHTTPS)
}
de.https = (&url.URL{
Scheme: "https",
Host: addr,
Path: "/dns-query",
}).String()
}
if tlsConf.PortDNSOverTLS != 0 {
de.tls = (&url.URL{
Scheme: "tls",
Host: netutil.JoinHostPort(hostname, tlsConf.PortDNSOverTLS),
}).String()
}
if tlsConf.PortDNSOverQUIC != 0 {
de.quic = (&url.URL{
Scheme: "quic",
Host: netutil.JoinHostPort(hostname, tlsConf.PortDNSOverQUIC),
}).String()
}
}
return de
}
// applyAdditionalFiltering adds additional client information and settings if
// the client has them.
func applyAdditionalFiltering(clientIP net.IP, clientID string, setts *filtering.Settings) {
// pref is a prefix for logging messages around the scope.
const pref = "applying filters"
Context.filters.ApplyBlockedServices(setts, nil)
log.Debug("%s: looking for client with ip %s and clientid %q", pref, clientIP, clientID)
if clientIP == nil {
return
}
setts.ClientIP = clientIP
c, ok := Context.clients.Find(clientID)
if !ok {
c, ok = Context.clients.Find(clientIP.String())
if !ok {
log.Debug("%s: no clients with ip %s and clientid %q", pref, clientIP, clientID)
return
}
}
log.Debug("%s: using settings for client %q (%s; %q)", pref, c.Name, clientIP, clientID)
if c.UseOwnBlockedServices {
// TODO(e.burkov): Get rid of this crutch.
svcs := c.BlockedServices
if svcs == nil {
svcs = []string{}
}
Context.filters.ApplyBlockedServices(setts, svcs)
log.Debug("%s: services for client %q set: %s", pref, c.Name, svcs)
}
setts.ClientName = c.Name
setts.ClientTags = c.Tags
if !c.UseOwnSettings {
return
}
setts.FilteringEnabled = c.FilteringEnabled
setts.SafeSearchEnabled = c.SafeSearchEnabled
setts.SafeBrowsingEnabled = c.SafeBrowsingEnabled
setts.ParentalEnabled = c.ParentalEnabled
}
func startDNSServer() error {
config.RLock()
defer config.RUnlock()
if isRunning() {
return fmt.Errorf("unable to start forwarding DNS server: Already running")
}
Context.filters.EnableFilters(false)
Context.clients.Start()
err := Context.dnsServer.Start()
if err != nil {
return fmt.Errorf("couldn't start forwarding DNS server: %w", err)
}
Context.filters.Start()
Context.stats.Start()
Context.queryLog.Start()
const topClientsNumber = 100 // the number of clients to get
for _, ip := range Context.stats.TopClientsIP(topClientsNumber) {
if ip == nil {
continue
}
srcs := config.Clients.Sources
if srcs.RDNS && !ip.IsLoopback() {
Context.rdns.Begin(ip)
}
if srcs.WHOIS && !netutil.IsSpecialPurpose(ip) {
Context.whois.Begin(ip)
}
}
return nil
}
func reconfigureDNSServer() (err error) {
var newConf dnsforward.ServerConfig
newConf, err = generateServerConfig()
if err != nil {
return fmt.Errorf("generating forwarding dns server config: %w", err)
}
err = Context.dnsServer.Reconfigure(&newConf)
if err != nil {
return fmt.Errorf("starting forwarding dns server: %w", err)
}
return nil
}
func stopDNSServer() (err error) {
if !isRunning() {
return nil
}
err = Context.dnsServer.Stop()
if err != nil {
return fmt.Errorf("stopping forwarding dns server: %w", err)
}
err = Context.clients.close()
if err != nil {
return fmt.Errorf("closing clients container: %w", err)
}
closeDNSServer()
return nil
}
func closeDNSServer() {
// DNS forward module must be closed BEFORE stats or queryLog because it depends on them
if Context.dnsServer != nil {
Context.dnsServer.Close()
Context.dnsServer = nil
}
Context.filters.Close()
if Context.stats != nil {
err := Context.stats.Close()
if err != nil {
log.Debug("closing stats: %s", err)
}
// TODO(e.burkov): Find out if it's safe.
Context.stats = nil
}
if Context.queryLog != nil {
Context.queryLog.Close()
Context.queryLog = nil
}
log.Debug("all dns modules are closed")
}