documentation: Bump version

Co-authored-by: anytls <anytls>

common/dialer/dialer.go

@@ -104,7 +104,12 @@ func NewWithOptions(options Options) (N.Dialer, error) {
 		} else if options.NewDialer {
 			return nil, E.New("missing domain resolver for domain server address")
 		} else {
-			deprecated.Report(options.Context, deprecated.OptionMissingDomainResolver)
+			transports := dnsTransport.Transports()
+			if len(transports) < 2 {
+				dnsQueryOptions.Transport = dnsTransport.Default()
+			} else {
+				deprecated.Report(options.Context, deprecated.OptionMissingDomainResolver)
+			}
 		}
 		dialer = NewResolveDialer(
 			options.Context,

docs/changelog.md

@@ -4,8 +4,15 @@ icon: material/alert-decagram
 
 #### 1.12.0-alpha.16
 
+* Update `domain_resolver` behavior **1**
 * Fixes and improvements
 
+**1**:
+
+`route.default_domain_resolver` or `outbound.domain_resolver` is now optional when only one DNS server is configured.
+
+See [Dial Fields](/configuration/shared/dial/#domain_resolver).
+
 ### 1.11.5
 
 * Fixes and improvements

docs/configuration/shared/dial.md

@@ -106,6 +106,10 @@ Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
 
     `outbound` DNS rule items are deprecated and will be removed in sing-box 1.14.0, so this item will be required for outbound/endpoints using domain name in server address since sing-box 1.14.0.
 
+!!! info ""
+
+    `domain_resolver` or `route.default_domain_resolver` is optional when only one DNS server is configured.
+
 Set domain resolver to use for resolving domain names.
 
 This option uses the same format as the [route DNS rule action](/configuration/dns/rule_action/#route) without the `action` field.

docs/configuration/shared/dial.zh.md

@@ -105,6 +105,10 @@ icon: material/new-box
 
     `outbound` DNS 规则项已弃用，且将在 sing-box 1.14.0 中被移除。因此，从 sing-box 1.14.0 版本开始，所有在服务器地址中使用域名的出站/端点均需配置此项。
 
+!!! info ""
+
+    当只有一个 DNS 服务器已配置时，`domain_resolver` 或 `route.default_domain_resolver` 是可选的。 
+
 用于设置解析域名的域名解析器。
 
 此选项的格式与 [路由 DNS 规则动作](/configuration/dns/rule_action/#route) 相同，但不包含 `action` 字段。  

option/outbound.go

@@ -116,7 +116,14 @@ func (o *DomainResolveOptions) UnmarshalJSON(bytes []byte) error {
 		o.Server = stringValue
 		return nil
 	}
-	return json.Unmarshal(bytes, (*_DomainResolveOptions)(o))
+	err = json.Unmarshal(bytes, (*_DomainResolveOptions)(o))
+	if err != nil {
+		return err
+	}
+	if o.Server == "" {
+		return E.New("empty domain_resolver.server")
+	}
+	return nil
 }
 
 func (o *DialerOptions) TakeDialerOptions() DialerOptions {

route/conn.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"net"
 	"net/netip"
+	"os"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -14,6 +15,7 @@ import (
 	"github.com/sagernet/sing-box/common/tlsfragment"
 	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/buf"
 	"github.com/sagernet/sing/common/bufio"
 	"github.com/sagernet/sing/common/canceler"
 	E "github.com/sagernet/sing/common/exceptions"
@@ -206,14 +208,16 @@ func (m *ConnectionManager) NewPacketConnection(ctx context.Context, this N.Dial
 	go m.packetConnectionCopy(ctx, destination, conn, true, &done, onClose)
 }
 
-func (m *ConnectionManager) connectionCopy(ctx context.Context, source io.Reader, destination io.Writer, direction bool, done *atomic.Bool, onClose N.CloseHandlerFunc) {
-	originSource := source
-	originDestination := destination
+func (m *ConnectionManager) connectionCopy(ctx context.Context, source net.Conn, destination net.Conn, direction bool, done *atomic.Bool, onClose N.CloseHandlerFunc) {
+	var (
+		sourceReader      io.Reader = source
+		destinationWriter io.Writer = destination
+	)
 	var readCounters, writeCounters []N.CountFunc
 	for {
-		source, readCounters = N.UnwrapCountReader(source, readCounters)
-		destination, writeCounters = N.UnwrapCountWriter(destination, writeCounters)
-		if cachedSrc, isCached := source.(N.CachedReader); isCached {
+		sourceReader, readCounters = N.UnwrapCountReader(sourceReader, readCounters)
+		destinationWriter, writeCounters = N.UnwrapCountWriter(destinationWriter, writeCounters)
+		if cachedSrc, isCached := sourceReader.(N.CachedReader); isCached {
 			cachedBuffer := cachedSrc.ReadCached()
 			if cachedBuffer != nil {
 				dataLen := cachedBuffer.Len()
@@ -223,7 +227,7 @@ func (m *ConnectionManager) connectionCopy(ctx context.Context, source io.Reader
 					if done.Swap(true) {
 						onClose(err)
 					}
-					common.Close(originSource, originDestination)
+					common.Close(source, destination)
 					if !direction {
 						m.logger.ErrorContext(ctx, "connection upload payload: ", err)
 					} else {
@@ -242,9 +246,13 @@ func (m *ConnectionManager) connectionCopy(ctx context.Context, source io.Reader
 		}
 		break
 	}
-	if earlyConn, isEarlyConn := common.Cast[N.EarlyConn](destination); isEarlyConn && earlyConn.NeedHandshake() {
-		_, err := destination.Write(nil)
+	if earlyConn, isEarlyConn := common.Cast[N.EarlyConn](destinationWriter); isEarlyConn && earlyConn.NeedHandshake() {
+		err := m.connectionCopyEarly(source, destination)
 		if err != nil {
+			if done.Swap(true) {
+				onClose(err)
+			}
+			common.Close(source, destination)
 			if !direction {
 				m.logger.ErrorContext(ctx, "connection upload handshake: ", err)
 			} else {
@@ -253,20 +261,20 @@ func (m *ConnectionManager) connectionCopy(ctx context.Context, source io.Reader
 			return
 		}
 	}
-	_, err := bufio.CopyWithCounters(destination, source, originSource, readCounters, writeCounters)
+	_, err := bufio.CopyWithCounters(destination, sourceReader, source, readCounters, writeCounters)
 	if err != nil {
-		common.Close(originDestination)
+		common.Close(source, destination)
 	} else if duplexDst, isDuplex := destination.(N.WriteCloser); isDuplex {
 		err = duplexDst.CloseWrite()
 		if err != nil {
-			common.Close(originSource, originDestination)
+			common.Close(source, destination)
 		}
 	} else {
-		common.Close(originDestination)
+		destination.Close()
 	}
 	if done.Swap(true) {
 		onClose(err)
-		common.Close(originSource, originDestination)
+		common.Close(source, destination)
 	}
 	if !direction {
 		if err == nil {
@@ -287,6 +295,28 @@ func (m *ConnectionManager) connectionCopy(ctx context.Context, source io.Reader
 	}
 }
 
+func (m *ConnectionManager) connectionCopyEarly(source net.Conn, destination io.Writer) error {
+	payload := buf.NewPacket()
+	defer payload.Release()
+	err := source.SetReadDeadline(time.Now().Add(C.ReadPayloadTimeout))
+	if err != nil {
+		if err == os.ErrInvalid {
+			return common.Error(destination.Write(nil))
+		}
+		return err
+	}
+	_, err = payload.ReadOnceFrom(source)
+	if err != nil && !E.IsTimeout(err) {
+		return E.Cause(err, "read payload")
+	}
+	_ = source.SetReadDeadline(time.Time{})
+	_, err = destination.Write(payload.Bytes())
+	if err != nil {
+		return E.Cause(err, "write payload")
+	}
+	return nil
+}
+
 func (m *ConnectionManager) packetConnectionCopy(ctx context.Context, source N.PacketReader, destination N.PacketWriter, direction bool, done *atomic.Bool, onClose N.CloseHandlerFunc) {
 	_, err := bufio.CopyPacket(destination, source)
 	if !direction {