update

add conditional compilation support
add multi core support

core/xray/app/dispatcher/fakednssniffer.go

@@ -0,0 +1,119 @@
+package dispatcher
+
+import (
+	"context"
+	"strings"
+
+	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/common/session"
+	"github.com/xtls/xray-core/core"
+	"github.com/xtls/xray-core/features/dns"
+)
+
+// newFakeDNSSniffer Creates a Fake DNS metadata sniffer
+func newFakeDNSSniffer(ctx context.Context) (protocolSnifferWithMetadata, error) {
+	var fakeDNSEngine dns.FakeDNSEngine
+	{
+		fakeDNSEngineFeat := core.MustFromContext(ctx).GetFeature((*dns.FakeDNSEngine)(nil))
+		if fakeDNSEngineFeat != nil {
+			fakeDNSEngine = fakeDNSEngineFeat.(dns.FakeDNSEngine)
+		}
+	}
+
+	if fakeDNSEngine == nil {
+		errNotInit := newError("FakeDNSEngine is not initialized, but such a sniffer is used").AtError()
+		return protocolSnifferWithMetadata{}, errNotInit
+	}
+	return protocolSnifferWithMetadata{protocolSniffer: func(ctx context.Context, bytes []byte) (SniffResult, error) {
+		Target := session.OutboundFromContext(ctx).Target
+		if Target.Network == net.Network_TCP || Target.Network == net.Network_UDP {
+			domainFromFakeDNS := fakeDNSEngine.GetDomainFromFakeDNS(Target.Address)
+			if domainFromFakeDNS != "" {
+				newError("fake dns got domain: ", domainFromFakeDNS, " for ip: ", Target.Address.String()).WriteToLog(session.ExportIDToError(ctx))
+				return &fakeDNSSniffResult{domainName: domainFromFakeDNS}, nil
+			}
+		}
+
+		if ipAddressInRangeValueI := ctx.Value(ipAddressInRange); ipAddressInRangeValueI != nil {
+			ipAddressInRangeValue := ipAddressInRangeValueI.(*ipAddressInRangeOpt)
+			if fkr0, ok := fakeDNSEngine.(dns.FakeDNSEngineRev0); ok {
+				inPool := fkr0.IsIPInIPPool(Target.Address)
+				ipAddressInRangeValue.addressInRange = &inPool
+			}
+		}
+
+		return nil, common.ErrNoClue
+	}, metadataSniffer: true}, nil
+}
+
+type fakeDNSSniffResult struct {
+	domainName string
+}
+
+func (fakeDNSSniffResult) Protocol() string {
+	return "fakedns"
+}
+
+func (f fakeDNSSniffResult) Domain() string {
+	return f.domainName
+}
+
+type fakeDNSExtraOpts int
+
+const ipAddressInRange fakeDNSExtraOpts = 1
+
+type ipAddressInRangeOpt struct {
+	addressInRange *bool
+}
+
+type DNSThenOthersSniffResult struct {
+	domainName           string
+	protocolOriginalName string
+}
+
+func (f DNSThenOthersSniffResult) IsProtoSubsetOf(protocolName string) bool {
+	return strings.HasPrefix(protocolName, f.protocolOriginalName)
+}
+
+func (DNSThenOthersSniffResult) Protocol() string {
+	return "fakedns+others"
+}
+
+func (f DNSThenOthersSniffResult) Domain() string {
+	return f.domainName
+}
+
+func newFakeDNSThenOthers(ctx context.Context, fakeDNSSniffer protocolSnifferWithMetadata, others []protocolSnifferWithMetadata) (
+	protocolSnifferWithMetadata, error,
+) { // nolint: unparam
+	// ctx may be used in the future
+	_ = ctx
+	return protocolSnifferWithMetadata{
+		protocolSniffer: func(ctx context.Context, bytes []byte) (SniffResult, error) {
+			ipAddressInRangeValue := &ipAddressInRangeOpt{}
+			ctx = context.WithValue(ctx, ipAddressInRange, ipAddressInRangeValue)
+			result, err := fakeDNSSniffer.protocolSniffer(ctx, bytes)
+			if err == nil {
+				return result, nil
+			}
+			if ipAddressInRangeValue.addressInRange != nil {
+				if *ipAddressInRangeValue.addressInRange {
+					for _, v := range others {
+						if v.metadataSniffer || bytes != nil {
+							if result, err := v.protocolSniffer(ctx, bytes); err == nil {
+								return DNSThenOthersSniffResult{domainName: result.Domain(), protocolOriginalName: result.Protocol()}, nil
+							}
+						}
+					}
+					return nil, common.ErrNoClue
+				}
+				newError("ip address not in fake dns range, return as is").AtDebug().WriteToLog()
+				return nil, common.ErrNoClue
+			}
+			newError("fake dns sniffer did not set address in range option, assume false.").AtWarning().WriteToLog()
+			return nil, common.ErrNoClue
+		},
+		metadataSniffer: false,
+	}, nil
+}