DNS: Fix some bugs; Refactors; Optimizations (#4659)

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patterniha 2025-04-29 12:09:57 +03:30 committed by GitHub
parent 1c4e246788
commit aa4134f4a6
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22 changed files with 658 additions and 978 deletions

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@ -4,12 +4,12 @@ import (
"bytes"
"context"
"crypto/tls"
go_errors "errors"
"fmt"
"io"
"net/http"
"net/url"
"strings"
"sync"
"time"
utls "github.com/refraction-networking/utls"
@ -21,12 +21,9 @@ import (
"github.com/xtls/xray-core/common/net/cnc"
"github.com/xtls/xray-core/common/protocol/dns"
"github.com/xtls/xray-core/common/session"
"github.com/xtls/xray-core/common/signal/pubsub"
"github.com/xtls/xray-core/common/task"
dns_feature "github.com/xtls/xray-core/features/dns"
"github.com/xtls/xray-core/features/routing"
"github.com/xtls/xray-core/transport/internet"
"golang.org/x/net/dns/dnsmessage"
"golang.org/x/net/http2"
)
@ -34,18 +31,14 @@ import (
// which is compatible with traditional dns over udp(RFC1035),
// thus most of the DOH implementation is copied from udpns.go
type DoHNameServer struct {
sync.RWMutex
ips map[string]*record
pub *pubsub.Service
cleanup *task.Periodic
httpClient *http.Client
dohURL string
name string
queryStrategy QueryStrategy
cacheController *CacheController
httpClient *http.Client
dohURL string
clientIP net.IP
}
// NewDoHNameServer creates DOH/DOHL client object for remote/local resolving.
func NewDoHNameServer(url *url.URL, queryStrategy QueryStrategy, dispatcher routing.Dispatcher, h2c bool) *DoHNameServer {
func NewDoHNameServer(url *url.URL, dispatcher routing.Dispatcher, h2c bool, disableCache bool, clientIP net.IP) *DoHNameServer {
url.Scheme = "https"
mode := "DOH"
if dispatcher == nil {
@ -53,15 +46,9 @@ func NewDoHNameServer(url *url.URL, queryStrategy QueryStrategy, dispatcher rout
}
errors.LogInfo(context.Background(), "DNS: created ", mode, " client for ", url.String(), ", with h2c ", h2c)
s := &DoHNameServer{
ips: make(map[string]*record),
pub: pubsub.NewService(),
name: mode + "//" + url.Host,
dohURL: url.String(),
queryStrategy: queryStrategy,
}
s.cleanup = &task.Periodic{
Interval: time.Minute,
Execute: s.Cleanup,
cacheController: NewCacheController(mode+"//"+url.Host, disableCache),
dohURL: url.String(),
clientIP: clientIP,
}
s.httpClient = &http.Client{
Transport: &http2.Transport{
@ -127,101 +114,25 @@ func NewDoHNameServer(url *url.URL, queryStrategy QueryStrategy, dispatcher rout
// Name implements Server.
func (s *DoHNameServer) Name() string {
return s.name
}
// Cleanup clears expired items from cache
func (s *DoHNameServer) Cleanup() error {
now := time.Now()
s.Lock()
defer s.Unlock()
if len(s.ips) == 0 {
return errors.New("nothing to do. stopping...")
}
for domain, record := range s.ips {
if record.A != nil && record.A.Expire.Before(now) {
record.A = nil
}
if record.AAAA != nil && record.AAAA.Expire.Before(now) {
record.AAAA = nil
}
if record.A == nil && record.AAAA == nil {
errors.LogDebug(context.Background(), s.name, " cleanup ", domain)
delete(s.ips, domain)
} else {
s.ips[domain] = record
}
}
if len(s.ips) == 0 {
s.ips = make(map[string]*record)
}
return nil
}
func (s *DoHNameServer) updateIP(req *dnsRequest, ipRec *IPRecord) {
elapsed := time.Since(req.start)
s.Lock()
rec, found := s.ips[req.domain]
if !found {
rec = &record{}
}
updated := false
switch req.reqType {
case dnsmessage.TypeA:
if isNewer(rec.A, ipRec) {
rec.A = ipRec
updated = true
}
case dnsmessage.TypeAAAA:
addr := make([]net.Address, 0, len(ipRec.IP))
for _, ip := range ipRec.IP {
if len(ip.IP()) == net.IPv6len {
addr = append(addr, ip)
}
}
ipRec.IP = addr
if isNewer(rec.AAAA, ipRec) {
rec.AAAA = ipRec
updated = true
}
}
errors.LogInfo(context.Background(), s.name, " got answer: ", req.domain, " ", req.reqType, " -> ", ipRec.IP, " ", elapsed)
if updated {
s.ips[req.domain] = rec
}
switch req.reqType {
case dnsmessage.TypeA:
s.pub.Publish(req.domain+"4", nil)
case dnsmessage.TypeAAAA:
s.pub.Publish(req.domain+"6", nil)
}
s.Unlock()
common.Must(s.cleanup.Start())
return s.cacheController.name
}
func (s *DoHNameServer) newReqID() uint16 {
return 0
}
func (s *DoHNameServer) sendQuery(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption) {
errors.LogInfo(ctx, s.name, " querying: ", domain)
func (s *DoHNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- error, domain string, option dns_feature.IPOption) {
errors.LogInfo(ctx, s.Name(), " querying: ", domain)
if s.name+"." == "DOH//"+domain {
errors.LogError(ctx, s.name, " tries to resolve itself! Use IP or set \"hosts\" instead.")
if s.Name()+"." == "DOH//"+domain {
errors.LogError(ctx, s.Name(), " tries to resolve itself! Use IP or set \"hosts\" instead.")
noResponseErrCh <- errors.New("tries to resolve itself!", s.Name())
return
}
// As we don't want our traffic pattern looks like DoH, we use Random-Length Padding instead of Block-Length Padding recommended in RFC 8467
// Although DoH server like 1.1.1.1 will pad the response to Block-Length 468, at least it is better than no padding for response at all
reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(clientIP, int(crypto.RandBetween(100, 300))))
reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(s.clientIP, int(crypto.RandBetween(100, 300))))
var deadline time.Time
if d, ok := ctx.Deadline(); ok {
@ -256,19 +167,22 @@ func (s *DoHNameServer) sendQuery(ctx context.Context, domain string, clientIP n
b, err := dns.PackMessage(r.msg)
if err != nil {
errors.LogErrorInner(ctx, err, "failed to pack dns query for ", domain)
noResponseErrCh <- err
return
}
resp, err := s.dohHTTPSContext(dnsCtx, b.Bytes())
if err != nil {
errors.LogErrorInner(ctx, err, "failed to retrieve response for ", domain)
noResponseErrCh <- err
return
}
rec, err := parseResponse(resp)
if err != nil {
errors.LogErrorInner(ctx, err, "failed to handle DOH response for ", domain)
noResponseErrCh <- err
return
}
s.updateIP(r, rec)
s.cacheController.updateIP(r, rec)
}(req)
}
}
@ -301,109 +215,50 @@ func (s *DoHNameServer) dohHTTPSContext(ctx context.Context, b []byte) ([]byte,
return io.ReadAll(resp.Body)
}
func (s *DoHNameServer) findIPsForDomain(domain string, option dns_feature.IPOption) ([]net.IP, uint32, error) {
s.RLock()
record, found := s.ips[domain]
s.RUnlock()
if !found {
return nil, 0, errRecordNotFound
}
var err4 error
var err6 error
var ips []net.Address
var ip6 []net.Address
var ttl uint32
if option.IPv4Enable {
ips, ttl, err4 = record.A.getIPs()
}
if option.IPv6Enable {
ip6, ttl, err6 = record.AAAA.getIPs()
ips = append(ips, ip6...)
}
if len(ips) > 0 {
netips, err := toNetIP(ips)
return netips, ttl, err
}
if err4 != nil {
return nil, 0, err4
}
if err6 != nil {
return nil, 0, err6
}
if (option.IPv4Enable && record.A != nil) || (option.IPv6Enable && record.AAAA != nil) {
return nil, 0, dns_feature.ErrEmptyResponse
}
return nil, 0, errRecordNotFound
}
// QueryIP implements Server.
func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption, disableCache bool) ([]net.IP, uint32, error) { // nolint: dupl
func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, option dns_feature.IPOption) ([]net.IP, uint32, error) { // nolint: dupl
fqdn := Fqdn(domain)
option = ResolveIpOptionOverride(s.queryStrategy, option)
if !option.IPv4Enable && !option.IPv6Enable {
return nil, 0, dns_feature.ErrEmptyResponse
}
sub4, sub6 := s.cacheController.registerSubscribers(fqdn, option)
defer closeSubscribers(sub4, sub6)
if disableCache {
errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.name)
if s.cacheController.disableCache {
errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.Name())
} else {
ips, ttl, err := s.findIPsForDomain(fqdn, option)
if err == nil || err == dns_feature.ErrEmptyResponse || dns_feature.RCodeFromError(err) == 3 {
errors.LogDebugInner(ctx, err, s.name, " cache HIT ", domain, " -> ", ips)
log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
if !go_errors.Is(err, errRecordNotFound) {
errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
return ips, ttl, err
}
}
// ipv4 and ipv6 belong to different subscription groups
var sub4, sub6 *pubsub.Subscriber
if option.IPv4Enable {
sub4 = s.pub.Subscribe(fqdn + "4")
defer sub4.Close()
}
if option.IPv6Enable {
sub6 = s.pub.Subscribe(fqdn + "6")
defer sub6.Close()
}
done := make(chan interface{})
go func() {
if sub4 != nil {
select {
case <-sub4.Wait():
case <-ctx.Done():
}
}
if sub6 != nil {
select {
case <-sub6.Wait():
case <-ctx.Done():
}
}
close(done)
}()
s.sendQuery(ctx, fqdn, clientIP, option)
noResponseErrCh := make(chan error, 2)
s.sendQuery(ctx, noResponseErrCh, fqdn, option)
start := time.Now()
for {
ips, ttl, err := s.findIPsForDomain(fqdn, option)
if err != errRecordNotFound {
log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSQueried, Elapsed: time.Since(start), Error: err})
return ips, ttl, err
}
if sub4 != nil {
select {
case <-ctx.Done():
return nil, 0, ctx.Err()
case <-done:
case err := <-noResponseErrCh:
return nil, 0, err
case <-sub4.Wait():
sub4.Close()
}
}
if sub6 != nil {
select {
case <-ctx.Done():
return nil, 0, ctx.Err()
case err := <-noResponseErrCh:
return nil, 0, err
case <-sub6.Wait():
sub6.Close()
}
}
ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSQueried, Elapsed: time.Since(start), Error: err})
return ips, ttl, err
}