sing-box/protocol/tailscale/dns_transport.go
2025-01-12 14:40:01 +08:00

316 lines
9.7 KiB
Go

package tailscale
import (
"context"
"net"
"net/http"
"net/netip"
"net/url"
"os"
"reflect"
"strings"
"sync"
"github.com/sagernet/sing-box/adapter"
"github.com/sagernet/sing-box/common/dialer"
"github.com/sagernet/sing-box/common/tls"
C "github.com/sagernet/sing-box/constant"
"github.com/sagernet/sing-box/dns"
"github.com/sagernet/sing-box/dns/transport"
"github.com/sagernet/sing-box/log"
"github.com/sagernet/sing-box/option"
"github.com/sagernet/sing/common"
E "github.com/sagernet/sing/common/exceptions"
"github.com/sagernet/sing/common/logger"
M "github.com/sagernet/sing/common/metadata"
N "github.com/sagernet/sing/common/network"
"github.com/sagernet/sing/service"
nDNS "github.com/sagernet/tailscale/net/dns"
"github.com/sagernet/tailscale/types/dnstype"
"github.com/sagernet/tailscale/wgengine/router"
"github.com/sagernet/tailscale/wgengine/wgcfg"
mDNS "github.com/miekg/dns"
"go4.org/netipx"
"golang.org/x/net/http2"
)
func RegistryTransport(registry *dns.TransportRegistry) {
dns.RegisterTransport[option.TailscaleDNSServerOptions](registry, C.DNSTypeTailscale, NewDNSTransport)
}
type DNSTransport struct {
dns.TransportAdapter
ctx context.Context
logger logger.ContextLogger
endpointTag string
acceptDefaultResolvers bool
dnsRouter adapter.DNSRouter
endpointManager adapter.EndpointManager
cfg *wgcfg.Config
dnsCfg *nDNS.Config
endpoint *Endpoint
routePrefixes []netip.Prefix
routes map[string][]adapter.DNSTransport
hosts map[string][]netip.Addr
defaultResolvers []adapter.DNSTransport
}
func NewDNSTransport(ctx context.Context, logger log.ContextLogger, tag string, options option.TailscaleDNSServerOptions) (adapter.DNSTransport, error) {
if options.Endpoint == "" {
return nil, E.New("missing tailscale endpoint tag")
}
return &DNSTransport{
TransportAdapter: dns.NewTransportAdapter(C.DNSTypeTailscale, tag, nil),
ctx: ctx,
logger: logger,
endpointTag: options.Endpoint,
acceptDefaultResolvers: options.AcceptDefaultResolvers,
dnsRouter: service.FromContext[adapter.DNSRouter](ctx),
endpointManager: service.FromContext[adapter.EndpointManager](ctx),
}, nil
}
func (t *DNSTransport) Start(stage adapter.StartStage) error {
if stage != adapter.StartStateInitialize {
return nil
}
rawOutbound, loaded := t.endpointManager.Get(t.endpointTag)
if !loaded {
return E.New("endpoint not found: ", t.endpointTag)
}
ep, isTailscale := rawOutbound.(*Endpoint)
if !isTailscale {
return E.New("endpoint is not tailscale: ", t.endpointTag)
}
if ep.onReconfig != nil {
return E.New("only one tailscale DNS server is allowed for single endpoint")
}
ep.onReconfig = t.onReconfig
t.endpoint = ep
return nil
}
func (t *DNSTransport) Reset() {
}
func (t *DNSTransport) onReconfig(cfg *wgcfg.Config, routerCfg *router.Config, dnsCfg *nDNS.Config) {
if cfg == nil || dnsCfg == nil {
return
}
if (t.cfg != nil && reflect.DeepEqual(t.cfg, cfg)) && (t.dnsCfg != nil && reflect.DeepEqual(t.dnsCfg, dnsCfg)) {
return
}
t.cfg = cfg
t.dnsCfg = dnsCfg
err := t.updateDNSServers(routerCfg, dnsCfg)
if err != nil {
t.logger.Error(E.Cause(err, "update DNS servers"))
}
}
func (t *DNSTransport) updateDNSServers(routeConfig *router.Config, dnsConfig *nDNS.Config) error {
t.routePrefixes = buildRoutePrefixes(routeConfig)
directDialerOnce := sync.OnceValue(func() N.Dialer {
directDialer := common.Must1(dialer.NewDefault(t.ctx, option.DialerOptions{}))
return &DNSDialer{transport: t, fallbackDialer: directDialer}
})
routes := make(map[string][]adapter.DNSTransport)
for domain, resolvers := range dnsConfig.Routes {
var myResolvers []adapter.DNSTransport
for _, resolver := range resolvers {
myResolver, err := t.createResolver(directDialerOnce, resolver)
if err != nil {
return err
}
myResolvers = append(myResolvers, myResolver)
}
routes[domain.WithTrailingDot()] = myResolvers
}
hosts := make(map[string][]netip.Addr)
for domain, addresses := range dnsConfig.Hosts {
hosts[domain.WithTrailingDot()] = addresses
}
var defaultResolvers []adapter.DNSTransport
for _, resolver := range dnsConfig.DefaultResolvers {
myResolver, err := t.createResolver(directDialerOnce, resolver)
if err != nil {
return err
}
defaultResolvers = append(defaultResolvers, myResolver)
}
t.routes = routes
t.hosts = hosts
t.defaultResolvers = defaultResolvers
if len(defaultResolvers) > 0 {
t.logger.Info("updated ", len(routes), " routes, ", len(hosts), " hosts, default resolvers: ",
strings.Join(common.Map(dnsConfig.DefaultResolvers, func(it *dnstype.Resolver) string { return it.Addr }), " "))
} else {
t.logger.Info("updated ", len(routes), " routes, ", len(hosts), " hosts")
}
return nil
}
func (t *DNSTransport) createResolver(directDialer func() N.Dialer, resolver *dnstype.Resolver) (adapter.DNSTransport, error) {
serverURL, parseURLErr := url.Parse(resolver.Addr)
var myDialer N.Dialer
if parseURLErr == nil && serverURL.Scheme == "http" {
myDialer = t.endpoint
} else {
myDialer = directDialer()
}
if len(resolver.BootstrapResolution) > 0 {
bootstrapTransport := transport.NewUDPRaw(t.logger, t.TransportAdapter, myDialer, M.SocksaddrFrom(resolver.BootstrapResolution[0], 53))
myDialer = dns.NewTransportDialer(myDialer, t.dnsRouter, bootstrapTransport, C.DomainStrategyPreferIPv4, 0)
}
if serverAddr := M.ParseSocksaddr(resolver.Addr); serverAddr.IsValid() {
if serverAddr.Port == 0 {
serverAddr.Port = 53
}
return transport.NewUDPRaw(t.logger, t.TransportAdapter, myDialer, serverAddr), nil
} else if parseURLErr != nil {
return nil, E.Cause(parseURLErr, "parse resolver address")
} else {
switch serverURL.Scheme {
case "https":
serverAddr = M.ParseSocksaddrHostPortStr(serverURL.Hostname(), serverURL.Port())
if serverAddr.Port == 0 {
serverAddr.Port = 443
}
tlsConfig := common.Must1(tls.NewClient(t.ctx, serverAddr.AddrString(), option.OutboundTLSOptions{
ALPN: []string{http2.NextProtoTLS, "http/1.1"},
}))
return transport.NewHTTPSRaw(t.TransportAdapter, t.logger, myDialer, serverURL, http.Header{}, serverAddr, tlsConfig), nil
case "http":
serverAddr = M.ParseSocksaddrHostPortStr(serverURL.Hostname(), serverURL.Port())
if serverAddr.Port == 0 {
serverAddr.Port = 80
}
return transport.NewHTTPSRaw(t.TransportAdapter, t.logger, myDialer, serverURL, http.Header{}, serverAddr, nil), nil
// case "tls":
default:
return nil, E.New("unknown resolver scheme: ", serverURL.Scheme)
}
}
}
func buildRoutePrefixes(routeConfig *router.Config) []netip.Prefix {
var builder netipx.IPSetBuilder
for _, localAddr := range routeConfig.LocalAddrs {
builder.AddPrefix(localAddr)
}
for _, route := range routeConfig.Routes {
builder.AddPrefix(route)
}
for _, route := range routeConfig.LocalRoutes {
builder.AddPrefix(route)
}
for _, route := range routeConfig.SubnetRoutes {
builder.AddPrefix(route)
}
ipSet, err := builder.IPSet()
if err != nil {
return nil
}
return ipSet.Prefixes()
}
func (t *DNSTransport) Close() error {
return nil
}
func (t *DNSTransport) Raw() bool {
return true
}
func (t *DNSTransport) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg, error) {
if len(message.Question) != 1 {
return nil, os.ErrInvalid
}
question := message.Question[0]
addresses, hostsLoaded := t.hosts[question.Name]
if hostsLoaded {
switch question.Qtype {
case mDNS.TypeA:
addresses4 := common.Filter(addresses, func(addr netip.Addr) bool {
return addr.Is4()
})
if len(addresses4) > 0 {
return dns.FixedResponse(message.Id, question, addresses4, C.DefaultDNSTTL), nil
}
case mDNS.TypeAAAA:
addresses6 := common.Filter(addresses, func(addr netip.Addr) bool {
return addr.Is6()
})
if len(addresses6) > 0 {
return dns.FixedResponse(message.Id, question, addresses6, C.DefaultDNSTTL), nil
}
}
}
for domainSuffix, transports := range t.routes {
if strings.HasSuffix(question.Name, domainSuffix) {
if len(transports) == 0 {
return &mDNS.Msg{
MsgHdr: mDNS.MsgHdr{
Id: message.Id,
Rcode: mDNS.RcodeNameError,
Response: true,
},
Question: []mDNS.Question{question},
}, nil
}
var lastErr error
for _, dnsTransport := range transports {
response, err := dnsTransport.Exchange(ctx, message)
if err != nil {
lastErr = err
continue
}
return response, nil
}
return nil, lastErr
}
}
if t.acceptDefaultResolvers && len(t.defaultResolvers) > 0 {
var lastErr error
for _, resolver := range t.defaultResolvers {
response, err := resolver.Exchange(ctx, message)
if err != nil {
lastErr = err
continue
}
return response, nil
}
return nil, lastErr
}
return nil, dns.RCodeNameError
}
type DNSDialer struct {
transport *DNSTransport
fallbackDialer N.Dialer
}
func (d *DNSDialer) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
if destination.IsFqdn() {
panic("invalid request here")
}
for _, prefix := range d.transport.routePrefixes {
if prefix.Contains(destination.Addr) {
return d.transport.endpoint.DialContext(ctx, network, destination)
}
}
return d.fallbackDialer.DialContext(ctx, network, destination)
}
func (d *DNSDialer) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
if destination.IsFqdn() {
panic("invalid request here")
}
for _, prefix := range d.transport.routePrefixes {
if prefix.Contains(destination.Addr) {
return d.transport.endpoint.ListenPacket(ctx, destination)
}
}
return d.fallbackDialer.ListenPacket(ctx, destination)
}