show DNSMode in clash connection api

(cherry picked from commit cb3ccd5a187950d860ed41104e75d48f66ce5886)

adapter/inbound.go

@@ -43,6 +43,7 @@ type InboundContext struct {
 
 	// cache
 
+	DNSMode              string
 	InboundDetour        string
 	LastInbound          string
 	OriginDestination    M.Socksaddr

constant/dns.go

@@ -4,3 +4,8 @@ const (
 	DNSProviderAliDNS     = "alidns"
 	DNSProviderCloudflare = "cloudflare"
 )
+
+const (
+	DNSModeNormal = "normal"
+	DNSModeFakeIP = "fake-ip"
+)

experimental/clashapi/trafficontrol/tracker.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/atomic"
 	"github.com/sagernet/sing/common/bufio"
@@ -64,6 +65,12 @@ func (t TrackerMetadata) MarshalJSON() ([]byte, error) {
 	} else {
 		rule = "final"
 	}
+	var dnsMode string
+	if t.Metadata.DNSMode != "" {
+		dnsMode = t.Metadata.DNSMode
+	} else {
+		dnsMode = C.DNSModeNormal
+	}
 	return json.Marshal(map[string]any{
 		"id": t.ID,
 		"metadata": map[string]any{
@@ -74,7 +81,7 @@ func (t TrackerMetadata) MarshalJSON() ([]byte, error) {
 			"sourcePort":      F.ToString(t.Metadata.Source.Port),
 			"destinationPort": F.ToString(t.Metadata.Destination.Port),
 			"host":            domain,
-			"dnsMode":         "normal",
+			"dnsMode":         dnsMode,
 			"processPath":     processPath,
 		},
 		"upload":      t.Upload.Load(),

route/router.go

@@ -845,6 +845,7 @@ func (r *Router) RouteConnection(ctx context.Context, conn net.Conn, metadata ad
 			Fqdn: domain,
 			Port: metadata.Destination.Port,
 		}
+		metadata.DNSMode = C.DNSModeFakeIP
 		metadata.FakeIP = true
 		r.logger.DebugContext(ctx, "found fakeip domain: ", domain)
 	}
@@ -969,6 +970,7 @@ func (r *Router) RoutePacketConnection(ctx context.Context, conn N.PacketConn, m
 			Fqdn: domain,
 			Port: metadata.Destination.Port,
 		}
+		metadata.DNSMode = C.DNSModeFakeIP
 		metadata.FakeIP = true
 		r.logger.DebugContext(ctx, "found fakeip domain: ", domain)
 	}