feat: strengthen three-carrier return route detection

2026-08-13 12:19:16 +08:00 · 2026-07-31 00:30:42 +08:00 · 2026-07-31 00:30:42 +08:00 · 5369aa16f7
commit 5369aa16f7
parent c350b4e1f8
23 changed files with 1187 additions and 136 deletions
--- a/bk/backtrace.go
+++ b/bk/backtrace.go
@ -1,105 +1,10 @@
 package backtrace

 import (
-	"strings"
-	"time"
-
-	"github.com/oneclickvirt/backtrace/model"
+	"context"
 )

-func safeTraceCall(fn func()) {
-	defer func() {
-		if r := recover(); r != nil {
-		}
-	}()
-	fn()
-}
-
 func BackTrace(enableIpv6 bool) string {
-	StartASNPrefixRefresh()
-	if model.CachedIcmpData == "" || model.ParsedIcmpTargets == nil || time.Since(model.CachedIcmpDataFetchTime) > time.Hour {
-		model.CachedIcmpData = getData(model.IcmpTargets)
-		model.CachedIcmpDataFetchTime = time.Now()
-		if model.CachedIcmpData != "" {
-			model.ParsedIcmpTargets = parseIcmpTargets(model.CachedIcmpData)
-		}
-	}
-	var builder strings.Builder
-	if enableIpv6 {
-		ipv4Count := len(model.Ipv4s)
-		ipv6Count := len(model.Ipv6s)
-		totalCount := ipv4Count + ipv6Count
-		var (
-			s = make([]string, totalCount)
-			c = make(chan Result)
-			t = time.After(time.Second * 10)
-		)
-		for i := range model.Ipv4s {
-			idx := i
-			go safeTraceCall(func() {
-				trace(c, idx)
-			})
-		}
-		for i := range model.Ipv6s {
-			idx := i
-			go safeTraceCall(func() {
-				traceIPv6(c, idx, ipv4Count)
-			})
-		}
-	loopIPv4v6:
-		for range s {
-			select {
-			case o := <-c:
-				s[o.i] = o.s
-			case <-t:
-				break loopIPv4v6
-			}
-		}
-		// 收集 IPv4 结果
-		for i := 0; i < ipv4Count; i++ {
-			if s[i] != "" {
-				builder.WriteString(s[i])
-				builder.WriteString("\n")
-			}
-		}
-		// 收集 IPv6 结果
-		for i := ipv4Count; i < totalCount; i++ {
-			if s[i] != "" {
-				builder.WriteString(s[i])
-				builder.WriteString("\n")
-			}
-		}
-	} else {
-		ipCount := len(model.Ipv4s)
-		var (
-			s = make([]string, ipCount)
-			c = make(chan Result)
-			t = time.After(time.Second * 10)
-		)
-		for i := range model.Ipv4s {
-			idx := i
-			go safeTraceCall(func() {
-				trace(c, idx)
-			})
-		}
-	loopIPv4:
-		for range s {
-			select {
-			case o := <-c:
-				s[o.i] = o.s
-			case <-t:
-				break loopIPv4
-			}
-		}
-		// 收集结果
-		for _, r := range s {
-			if r != "" {
-				builder.WriteString(r)
-				builder.WriteString("\n")
-			}
-		}
-	}
-	// 返回完整结果，去掉末尾的换行符
-	result := builder.String()
-	return strings.TrimSuffix(result, "\n")
+	report := RunRouteReport(context.Background(), RouteReportConfig{EnableIPv6: enableIpv6})
+	return RenderRouteReport(report)
 }
--- a/bk/ipv4_asn.go
+++ b/bk/ipv4_asn.go
@ -1,6 +1,7 @@
 package backtrace

 import (
+	"net/netip"
 	"strings"
 )

@ -8,6 +9,11 @@ func ipv4Asn(ip string) string {
 	if strings.Contains(ip, ":") {
 		return ipv6Asn(ip)
 	}
+	address, err := netip.ParseAddr(strings.TrimSpace(ip))
+	if err != nil || !address.Is4() {
+		return ""
+	}
+	octets := address.As4()
 	switch {
 	case strings.HasPrefix(ip, "59.43"):
 		return "AS4809"
@ -15,17 +21,41 @@ func ipv4Asn(ip string) string {
 		return "AS4134"
 	case strings.HasPrefix(ip, "218.105") || strings.HasPrefix(ip, "210.51"):
 		return "AS9929"
+	case strings.HasPrefix(ip, "202.77") || strings.HasPrefix(ip, "43.252") || strings.HasPrefix(ip, "61.14"):
+		return "AS10099"
 	case strings.HasPrefix(ip, "219.158"):
 		return "AS4837"
-	case strings.HasPrefix(ip, "223.120.19") || strings.HasPrefix(ip, "223.120.17") || strings.HasPrefix(ip, "223.120.16") ||
-		strings.HasPrefix(ip, "223.120.140") || strings.HasPrefix(ip, "223.120.130") || strings.HasPrefix(ip, "223.120.131") ||
-		strings.HasPrefix(ip, "223.120.141"):
+	case isCMIN2IPv4(octets):
 		return "AS58807"
 	case strings.HasPrefix(ip, "223.118") || strings.HasPrefix(ip, "223.119") || strings.HasPrefix(ip, "223.120") || strings.HasPrefix(ip, "223.121"):
 		return "AS58453"
+	case strings.HasPrefix(ip, "221.183") || strings.HasPrefix(ip, "111.24"):
+		return "AS9808"
 	case strings.HasPrefix(ip, "69.194") || strings.HasPrefix(ip, "203.22"):
 		return "AS23764"
 	default:
 		return ""
 	}
 }
+
+func isCMIN2IPv4(ip [4]byte) bool {
+	if ip[0] != 223 {
+		return false
+	}
+	if ip[1] == 118 && ip[2] == 32 {
+		return true
+	}
+	if ip[1] == 120 && ip[2] >= 128 {
+		return true
+	}
+	if ip[1] != 119 {
+		return false
+	}
+	third := ip[2]
+	return third == 8 || third == 9 ||
+		(third >= 10 && third <= 15) ||
+		(third >= 26 && third <= 29) ||
+		(third >= 32 && third <= 37) ||
+		third == 74 || third == 75 || third == 88 || third == 89 ||
+		third == 100 || third == 252 || third == 253
+}
--- a/bk/ipv4_asn_test.go
+++ b/bk/ipv4_asn_test.go
@ -0,0 +1,31 @@
+package backtrace
+
+import "testing"
+
+func TestIPv4ASNBackboneSignatures(t *testing.T) {
+	tests := map[string]string{
+		"59.43.1.1":     "AS4809",
+		"202.97.1.1":    "AS4134",
+		"218.105.1.1":   "AS9929",
+		"202.77.1.1":    "AS10099",
+		"219.158.1.1":   "AS4837",
+		"223.118.32.1":  "AS58807",
+		"223.119.100.1": "AS58807",
+		"223.120.128.1": "AS58807",
+		"223.120.127.1": "AS58453",
+		"221.183.1.1":   "AS9808",
+		"69.194.1.1":    "AS23764",
+		"192.0.2.1":     "",
+	}
+	for address, want := range tests {
+		if got := ipv4Asn(address); got != want {
+			t.Fatalf("ipv4Asn(%q) = %q, want %q", address, got, want)
+		}
+	}
+}
+
+func TestIPv6ASNRecognizesCUGSnapshot(t *testing.T) {
+	if got := ipv6Asn("2401:8a00:1:12::1"); got != "AS10099" {
+		t.Fatalf("ipv6Asn(CUG) = %q, want AS10099", got)
+	}
+}
--- a/bk/ipv6_asn.go
+++ b/bk/ipv6_asn.go
@ -15,6 +15,9 @@ var as4134Data string
 //go:embed prefix/as9929.txt
 var as9929Data string

+//go:embed prefix/as10099.txt
+var as10099Data string
+
 //go:embed prefix/as4837.txt
 var as4837Data string

@ -35,6 +38,7 @@ var asnPrefixes = map[string][]string{
 	"AS4809":  strings.Split(as4809Data, "\n"),  // 电信 CN2 GT/GIA
 	"AS4134":  strings.Split(as4134Data, "\n"),  // 电信 163 骨干网
 	"AS9929":  strings.Split(as9929Data, "\n"),  // 联通 9929 优质国际线路
+	"AS10099": strings.Split(as10099Data, "\n"), // 联通 CUG 国际网络
 	"AS4837":  strings.Split(as4837Data, "\n"),  // 联通 AS4837 普通国际线路
 	"AS58807": strings.Split(as58807Data, "\n"), // 移动 CMIN2 国际精品网
 	"AS9808":  strings.Split(as9808Data, "\n"),  // 移动 CMI（中国移动国际公司）
@ -45,6 +49,12 @@ var asnPrefixes = map[string][]string{
 // 判断 IPv6 地址是否匹配 ASN 中的某个前缀
 func ipv6Asn(ip string) string {
 	ip = strings.ToLower(ip)
+	address, addressErr := netip.ParseAddr(ip)
+	if addressErr != nil || !address.Is6() {
+		return ""
+	}
+	bestASN := ""
+	bestSpecificity := -1
 	for asn, prefixes := range currentASNPrefixes() {
 		for _, prefix := range prefixes {
 			prefix = strings.TrimSpace(prefix)
@ -52,17 +62,35 @@ func ipv6Asn(ip string) string {
 				continue
 			}
 			if strings.Contains(prefix, "/") {
-				address, addressErr := netip.ParseAddr(ip)
 				network, networkErr := netip.ParsePrefix(prefix)
-				if addressErr == nil && networkErr == nil && network.Contains(address) {
-					return asn
+				if networkErr == nil && network.Contains(address) &&
+					(network.Bits() > bestSpecificity || (network.Bits() == bestSpecificity && asn < bestASN)) {
+					bestASN = asn
+					bestSpecificity = network.Bits()
 				}
 				continue
 			}
 			if strings.HasPrefix(ip, prefix) {
-				return asn
+				specificity := prefixHexBits(prefix)
+				if specificity > bestSpecificity || (specificity == bestSpecificity && asn < bestASN) {
+					bestASN = asn
+					bestSpecificity = specificity
+				}
 			}
 		}
 	}
-	return ""
+	return bestASN
+}
+
+func prefixHexBits(prefix string) int {
+	bits := 0
+	for _, value := range prefix {
+		switch {
+		case value >= '0' && value <= '9':
+			bits += 4
+		case value >= 'a' && value <= 'f':
+			bits += 4
+		}
+	}
+	return bits
 }
--- a/bk/prefix/as10099.txt
+++ b/bk/prefix/as10099.txt
@ -0,0 +1,10 @@
+2401:8a00:13::/48
+2401:8a00:1:12::/64
+2401:8a00:1:14::/64
+2401:8a00:1:17::/64
+2401:8a00:1:2::/64
+2401:8a00:1:3::/64
+2401:8a00:1:7::/64
+2401:8a00:1:c::/64
+2401:8a00::/32
+2401:8a00:d::/48
--- a/bk/prefix/as10099.txt.manifest.json
+++ b/bk/prefix/as10099.txt.manifest.json
@ -0,0 +1,7 @@
+{
+  "schema": "backtrace.asn-prefixes/v1",
+  "file": "as10099.txt",
+  "count": 10,
+  "sha256": "7161aad3d31fb89f43234e03ed95c63c51e2ef5c4d49c9223126d01384fe7cba",
+  "generated_at": "2026-07-30T15:51:08Z"
+}
--- a/bk/prefix/as4134.txt.manifest.json
+++ b/bk/prefix/as4134.txt.manifest.json
@ -3,5 +3,5 @@
  "file": "as4134.txt",
  "count": 629,
  "sha256": "00941f76c022566166b926670ee9358084c53465cbaaf75a3da7b73d997d1947",
-  "generated_at": "2026-07-23T02:56:31Z"
+  "generated_at": "2026-07-30T15:51:08Z"
 }
--- a/bk/prefix/as4809.txt
+++ b/bk/prefix/as4809.txt
@ -108,6 +108,7 @@
 240e:650:8000::/38
 240e:659:f100::/48
 240e:65f:100::/48
+240e:65f:800::/48
 240e:65f:e000::/36
 240e:669:b000::/40
 240e:670:d000::/36
@ -138,6 +139,8 @@
 240e:767:f000::/48
 240e:787:7000::/48
 240e:787:7001::/48
+240e:790:fe10::/48
+240e:790:fe20::/48
 240e:790:ff00::/40
 240e:7b6::/31
 240e:965:822::/48
--- a/bk/prefix/as4809.txt.manifest.json
+++ b/bk/prefix/as4809.txt.manifest.json
@ -1,7 +1,7 @@
 {
  "schema": "backtrace.asn-prefixes/v1",
  "file": "as4809.txt",
-  "count": 185,
-  "sha256": "943e26cef20a0a7faba55c98825d89933a597b885ab01766ce2d1b0a58f9c8f0",
-  "generated_at": "2026-07-30T02:34:19Z"
+  "count": 188,
+  "sha256": "a43638fa67e5057d237988233101ef0bfd4f5557001325289e0846af642670ae",
+  "generated_at": "2026-07-30T15:51:08Z"
 }
--- a/bk/prefix/as4837.txt.manifest.json
+++ b/bk/prefix/as4837.txt.manifest.json
@ -3,5 +3,5 @@
  "file": "as4837.txt",
  "count": 492,
  "sha256": "40ece28148fc843764a9b1cec48d07013d6e6fdc8697b601af93a45093e1908c",
-  "generated_at": "2026-07-29T02:49:32Z"
+  "generated_at": "2026-07-30T15:51:08Z"
 }
--- a/bk/prefix/as9808.txt.manifest.json
+++ b/bk/prefix/as9808.txt.manifest.json
@ -3,5 +3,5 @@
  "file": "as9808.txt",
  "count": 7171,
  "sha256": "ba623bf5d30f2c69340ffdd2c4d50bfc79506b00ebdbc8a2f0448b7ce21148e1",
-  "generated_at": "2026-07-30T02:34:19Z"
+  "generated_at": "2026-07-30T15:51:08Z"
 }
--- a/bk/prefix_registry.go
+++ b/bk/prefix_registry.go
@ -26,7 +26,7 @@ const (
 	ASNPrefixRegistryCDNBaseURL = "https://cdn.spiritlhl.net/" + ASNPrefixRegistryRawBaseURL
 )

-var knownPrefixASNs = []string{"AS23764", "AS4134", "AS4809", "AS4837", "AS58453", "AS58807", "AS9808", "AS9929"}
+var knownPrefixASNs = []string{"AS10099", "AS23764", "AS4134", "AS4809", "AS4837", "AS58453", "AS58807", "AS9808", "AS9929"}
 var prefixFragmentPattern = regexp.MustCompile(`^[0-9a-fA-F:]+$`)

 type ASNPrefixRegistrySource struct {
@ -226,6 +226,8 @@ func validateEmbeddedPrefixManifests() error {
 		switch asn {
 		case "AS23764":
 			snapshot = []byte(as23764Data)
+		case "AS10099":
+			snapshot = []byte(as10099Data)
 		case "AS4134":
 			snapshot = []byte(as4134Data)
 		case "AS4809":
--- a/bk/route_classification.go
+++ b/bk/route_classification.go
@ -0,0 +1,238 @@
+package backtrace
+
+import "strings"
+
+// RouteHopEvidence is the ordered ASN evidence observed at one responding hop.
+// A hop can contain more than one ASN when repeated traces take different paths.
+type RouteHopEvidence struct {
+	Distance int      `json:"distance"`
+	ASNs     []string `json:"asns,omitempty"`
+}
+
+// RouteClassification is a conservative classification of a China-carrier
+// return route. Code and Confidence are stable machine-readable values; Label
+// preserves the compact legacy display used by backtrace and ecs.
+type RouteClassification struct {
+	Code       string `json:"code"`
+	Label      string `json:"label"`
+	Confidence string `json:"confidence"`
+	Rank       int    `json:"rank"`
+	Evidence   string `json:"evidence"`
+}
+
+const (
+	routeConfidenceConfirmed    = "confirmed"
+	routeConfidenceMixed        = "mixed"
+	routeConfidenceInconclusive = "inconclusive"
+)
+
+// ClassifyReturnRoute classifies ordered return-route evidence. Premium-route
+// claims require enough evidence to distinguish a backbone segment from a
+// single destination-network delivery hop.
+func ClassifyReturnRoute(carrier string, hops []RouteHopEvidence) RouteClassification {
+	carrier = normalizeCarrier(carrier)
+	switch carrier {
+	case "CT":
+		return classifyTelecom(hops)
+	case "CU":
+		return classifyUnicom(hops)
+	case "CM":
+		return classifyMobile(hops)
+	default:
+		return inconclusiveClassification("unknown_carrier", "线路证据不足", "unknown carrier")
+	}
+}
+
+func classifyTelecom(hops []RouteHopEvidence) RouteClassification {
+	cn2Index, cn2Hops := routeASNPosition(hops, "AS4809")
+	ct163Index, ct163Hops := routeASNPosition(hops, "AS4134")
+	ctgIndex, _ := routeASNPosition(hops, "AS23764")
+	if cn2Index >= 0 {
+		if cn2Hops < 2 {
+			return RouteClassification{
+				Code: "ct_cn2_mixed", Label: "电信CN2混合 [优质线路]", Confidence: routeConfidenceMixed, Rank: 3,
+				Evidence: "only one AS4809 hop; CN2 GIA is not confirmed",
+			}
+		}
+		if ct163Index < 0 || (cn2Index < ct163Index && ct163Hops <= 1) {
+			return RouteClassification{
+				Code: "ct_cn2_gia", Label: "电信CN2GIA [精品线路]", Confidence: routeConfidenceConfirmed, Rank: 5,
+				Evidence: "at least two AS4809 hops precede at most one AS4134 delivery hop",
+			}
+		}
+		if cn2Index < ct163Index {
+			return RouteClassification{
+				Code: "ct_cn2_mixed", Label: "电信CN2混合 [优质线路]", Confidence: routeConfidenceMixed, Rank: 3,
+				Evidence: "AS4809 is followed by multiple AS4134 backbone hops",
+			}
+		}
+		return RouteClassification{
+			Code: "ct_cn2_gt", Label: "电信CN2GT  [优质线路]", Confidence: routeConfidenceMixed, Rank: 3,
+			Evidence: "AS4134 appears before the AS4809 segment",
+		}
+	}
+	if ctgIndex >= 0 {
+		return RouteClassification{
+			Code: "ct_ctgnet", Label: "电信CTGNET [精品线路]", Confidence: routeConfidenceConfirmed, Rank: 4,
+			Evidence: "AS23764 is present",
+		}
+	}
+	if ct163Index >= 0 {
+		if ct163Hops <= 1 {
+			return inconclusiveClassification("ct_destination_only", "仅见电信目的网", "only one AS4134 hop")
+		}
+		return RouteClassification{
+			Code: "ct_163", Label: "电信163    [普通线路]", Confidence: routeConfidenceConfirmed, Rank: 2,
+			Evidence: "multiple AS4134 hops are present without premium backbone evidence",
+		}
+	}
+	return inconclusiveClassification("ct_unknown", "未见电信骨干", "AS4809, AS23764, and AS4134 are absent")
+}
+
+func classifyUnicom(hops []RouteHopEvidence) RouteClassification {
+	cu9929Index, _ := routeASNPosition(hops, "AS9929")
+	cugIndex, _ := routeASNPosition(hops, "AS10099")
+	cu4837Index, cu4837Hops := routeASNPosition(hops, "AS4837")
+	if cu9929Index >= 0 {
+		if cu4837Index >= 0 && cu4837Index < cu9929Index {
+			return RouteClassification{
+				Code: "cu_9929_mixed", Label: "联通9929混合 [优质线路]", Confidence: routeConfidenceMixed, Rank: 3,
+				Evidence: "AS4837 appears before the AS9929 segment",
+			}
+		}
+		return RouteClassification{
+			Code: "cu_9929", Label: "联通9929   [优质线路]", Confidence: routeConfidenceConfirmed, Rank: 5,
+			Evidence: "AS9929 is present without an earlier AS4837 segment",
+		}
+	}
+	if cugIndex >= 0 {
+		return RouteClassification{
+			Code: "cu_cug", Label: "联通CUG    [优质线路]", Confidence: routeConfidenceConfirmed, Rank: 3,
+			Evidence: "AS10099 is present without AS9929",
+		}
+	}
+	if cu4837Index >= 0 {
+		if cu4837Hops <= 1 {
+			return inconclusiveClassification("cu_destination_only", "仅见联通目的网", "only one AS4837 hop")
+		}
+		return RouteClassification{
+			Code: "cu_4837", Label: "联通4837   [普通线路]", Confidence: routeConfidenceConfirmed, Rank: 2,
+			Evidence: "multiple AS4837 hops are present without premium backbone evidence",
+		}
+	}
+	return inconclusiveClassification("cu_unknown", "未见联通骨干", "AS9929, AS10099, and AS4837 are absent")
+}
+
+func classifyMobile(hops []RouteHopEvidence) RouteClassification {
+	cmin2Index, _ := routeASNPosition(hops, "AS58807")
+	cmiIndex, _ := routeASNPosition(hops, "AS58453")
+	cmnetIndex, _ := routeASNPosition(hops, "AS9808")
+	if cmin2Index >= 0 {
+		if cmiIndex >= 0 && cmiIndex < cmin2Index {
+			return RouteClassification{
+				Code: "cm_cmin2_mixed", Label: "移动CMIN2混合 [优质线路]", Confidence: routeConfidenceMixed, Rank: 3,
+				Evidence: "AS58453 appears before the AS58807 segment",
+			}
+		}
+		return RouteClassification{
+			Code: "cm_cmin2", Label: "移动CMIN2  [精品线路]", Confidence: routeConfidenceConfirmed, Rank: 5,
+			Evidence: "AS58807 is present without an earlier AS58453 segment",
+		}
+	}
+	if cmiIndex >= 0 {
+		return RouteClassification{
+			Code: "cm_cmi", Label: "移动CMI    [普通线路]", Confidence: routeConfidenceConfirmed, Rank: 2,
+			Evidence: "AS58453 is present without CMIN2 evidence",
+		}
+	}
+	if cmnetIndex >= 0 {
+		return RouteClassification{
+			Code: "cm_cmnet", Label: "移动CMNET  [普通线路]", Confidence: routeConfidenceConfirmed, Rank: 2,
+			Evidence: "AS9808 is present without international premium backbone evidence",
+		}
+	}
+	return inconclusiveClassification("cm_unknown", "未见移动骨干", "AS58807, AS58453, and AS9808 are absent")
+}
+
+// combineRouteClassifications keeps useful results when one attempt is
+// inconclusive, but downgrades conflicting confirmed paths to a mixed result.
+func combineRouteClassifications(carrier string, values []RouteClassification) RouteClassification {
+	known := make([]RouteClassification, 0, len(values))
+	for _, value := range values {
+		if value.Confidence != routeConfidenceInconclusive {
+			known = append(known, value)
+		}
+	}
+	if len(known) == 0 {
+		if len(values) > 0 {
+			return values[0]
+		}
+		return inconclusiveClassification(strings.ToLower(normalizeCarrier(carrier))+"_unknown", "线路证据不足", "no classified route evidence")
+	}
+	best := known[0]
+	distinct := map[string]struct{}{best.Code: {}}
+	for _, value := range known[1:] {
+		distinct[value.Code] = struct{}{}
+		if value.Rank > best.Rank {
+			best = value
+		}
+	}
+	if len(distinct) == 1 {
+		return best
+	}
+	label := map[string]string{
+		"CT": "电信动态混合 [优质线路]",
+		"CU": "联通动态混合 [优质线路]",
+		"CM": "移动动态混合 [优质线路]",
+	}[normalizeCarrier(carrier)]
+	if label == "" {
+		label = "动态混合线路"
+	}
+	return RouteClassification{
+		Code: strings.ToLower(normalizeCarrier(carrier)) + "_dynamic_mixed", Label: label,
+		Confidence: routeConfidenceMixed, Rank: 3,
+		Evidence: "successful trace attempts observed conflicting backbone classes",
+	}
+}
+
+func routeASNPosition(hops []RouteHopEvidence, target string) (int, int) {
+	first := -1
+	count := 0
+	for index, hop := range hops {
+		matched := false
+		for _, asn := range hop.ASNs {
+			if strings.EqualFold(strings.TrimSpace(asn), target) {
+				matched = true
+				break
+			}
+		}
+		if matched {
+			if first < 0 {
+				first = index
+			}
+			count++
+		}
+	}
+	return first, count
+}
+
+func normalizeCarrier(value string) string {
+	value = strings.ToUpper(strings.TrimSpace(value))
+	switch value {
+	case "CT", "TELECOM", "电信":
+		return "CT"
+	case "CU", "UNICOM", "联通":
+		return "CU"
+	case "CM", "CMCC", "MOBILE", "移动":
+		return "CM"
+	default:
+		return value
+	}
+}
+
+func inconclusiveClassification(code, label, evidence string) RouteClassification {
+	return RouteClassification{
+		Code: code, Label: label, Confidence: routeConfidenceInconclusive,
+		Rank: 0, Evidence: evidence,
+	}
+}
--- a/bk/route_classification_test.go
+++ b/bk/route_classification_test.go
@ -0,0 +1,74 @@
+package backtrace
+
+import "testing"
+
+func routeFixture(asns ...string) []RouteHopEvidence {
+	hops := make([]RouteHopEvidence, 0, len(asns))
+	for index, asn := range asns {
+		hops = append(hops, RouteHopEvidence{Distance: index + 1, ASNs: []string{asn}})
+	}
+	return hops
+}
+
+func TestClassifyTelecomRequiresOrderedRepeatedEvidence(t *testing.T) {
+	tests := []struct {
+		name string
+		asns []string
+		code string
+		rank int
+	}{
+		{name: "single CN2 hop", asns: []string{"AS4809", "AS4134"}, code: "ct_cn2_mixed", rank: 3},
+		{name: "GIA with delivery hop", asns: []string{"AS4809", "AS4809", "AS4134"}, code: "ct_cn2_gia", rank: 5},
+		{name: "CN2 then 163 backbone", asns: []string{"AS4809", "AS4809", "AS4134", "AS4134"}, code: "ct_cn2_mixed", rank: 3},
+		{name: "163 before CN2", asns: []string{"AS4134", "AS4809", "AS4809"}, code: "ct_cn2_gt", rank: 3},
+		{name: "single destination hop", asns: []string{"AS4134"}, code: "ct_destination_only", rank: 0},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			result := ClassifyReturnRoute("CT", routeFixture(test.asns...))
+			if result.Code != test.code || result.Rank != test.rank {
+				t.Fatalf("ClassifyReturnRoute() = %+v, want code=%s rank=%d", result, test.code, test.rank)
+			}
+		})
+	}
+}
+
+func TestClassifyUnicomAddsCUGAndProtectsDestinationHop(t *testing.T) {
+	tests := []struct {
+		asns []string
+		code string
+	}{
+		{asns: []string{"AS9929", "AS9929", "AS4837"}, code: "cu_9929"},
+		{asns: []string{"AS4837", "AS9929"}, code: "cu_9929_mixed"},
+		{asns: []string{"AS10099"}, code: "cu_cug"},
+		{asns: []string{"AS4837"}, code: "cu_destination_only"},
+	}
+	for _, test := range tests {
+		result := ClassifyReturnRoute("CU", routeFixture(test.asns...))
+		if result.Code != test.code {
+			t.Fatalf("ClassifyReturnRoute(%v) = %+v, want %s", test.asns, result, test.code)
+		}
+	}
+}
+
+func TestClassifyMobileUsesOrderedCMIN2Evidence(t *testing.T) {
+	if result := ClassifyReturnRoute("CM", routeFixture("AS58807", "AS9808")); result.Code != "cm_cmin2" {
+		t.Fatalf("CMIN2 route = %+v", result)
+	}
+	if result := ClassifyReturnRoute("CM", routeFixture("AS58453", "AS58807")); result.Code != "cm_cmin2_mixed" {
+		t.Fatalf("mixed CMIN2 route = %+v", result)
+	}
+	if result := ClassifyReturnRoute("CM", routeFixture("AS9808")); result.Code != "cm_cmnet" {
+		t.Fatalf("CMNET route = %+v", result)
+	}
+}
+
+func TestCombineRouteClassificationsDowngradesDynamicDisagreement(t *testing.T) {
+	result := combineRouteClassifications("CU", []RouteClassification{
+		ClassifyReturnRoute("CU", routeFixture("AS9929")),
+		ClassifyReturnRoute("CU", routeFixture("AS4837", "AS4837")),
+	})
+	if result.Code != "cu_dynamic_mixed" || result.Confidence != routeConfidenceMixed || result.Rank != 3 {
+		t.Fatalf("combined route = %+v", result)
+	}
+}
--- a/bk/route_render.go
+++ b/bk/route_render.go
@ -0,0 +1,40 @@
+package backtrace
+
+import (
+	"fmt"
+	"strings"
+
+	. "github.com/oneclickvirt/defaultset"
+)
+
+// RenderRouteReport preserves the original compact one-target-per-line style.
+// Detailed hop statistics remain available in RouteReport JSON instead of
+// expanding the terminal section.
+func RenderRouteReport(report RouteReport) string {
+	var builder strings.Builder
+	for _, target := range report.Targets {
+		label := target.Classification.Label
+		if label == "" {
+			label = "线路证据不足"
+		}
+		var rendered string
+		switch {
+		case target.Status != RouteProbeAvailable:
+			rendered = Red("检测不到回程路由节点的IP地址")
+		case target.Classification.Confidence == routeConfidenceInconclusive:
+			rendered = Red(label)
+		case target.Classification.Rank >= 4:
+			rendered = DarkGreen(label)
+		case target.Classification.Rank == 3:
+			rendered = Green(label)
+		default:
+			rendered = White(label)
+		}
+		addressWidth := 15
+		if target.Target.IPVersion == "v6" {
+			addressWidth = 24
+		}
+		builder.WriteString(fmt.Sprintf("%v %-*s %v\n", target.Target.Name, addressWidth, target.Target.Address, rendered))
+	}
+	return strings.TrimSuffix(builder.String(), "\n")
+}
--- a/bk/route_report.go
+++ b/bk/route_report.go
@ -0,0 +1,441 @@
+package backtrace
+
+import (
+	"context"
+	"errors"
+	"math"
+	"net"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/oneclickvirt/backtrace/model"
+)
+
+const RouteReportSchema = "backtrace.routes/v1"
+
+type RouteProbeStatus string
+
+const (
+	RouteProbeAvailable   RouteProbeStatus = "available"
+	RouteProbeUnavailable RouteProbeStatus = "unavailable"
+	RouteProbeTimeout     RouteProbeStatus = "timeout"
+	RouteProbeCanceled    RouteProbeStatus = "canceled"
+)
+
+// RouteTarget identifies one carrier route without coupling the runner to the
+// built-in target registry. This also makes offline fixture tests possible.
+type RouteTarget struct {
+	Name      string `json:"name"`
+	Address   string `json:"address"`
+	IPVersion string `json:"ip_version"`
+	Carrier   string `json:"carrier"`
+}
+
+type RouteLatencyStats struct {
+	Samples  int     `json:"samples"`
+	MinMS    float64 `json:"min_ms"`
+	AvgMS    float64 `json:"avg_ms"`
+	P50MS    float64 `json:"p50_ms"`
+	P95MS    float64 `json:"p95_ms"`
+	MaxMS    float64 `json:"max_ms"`
+	JitterMS float64 `json:"jitter_ms"`
+}
+
+type RouteTargetReport struct {
+	Target             RouteTarget         `json:"target"`
+	Status             RouteProbeStatus    `json:"status"`
+	Protocol           string              `json:"protocol"`
+	Attempts           int                 `json:"attempts"`
+	SuccessfulAttempts int                 `json:"successful_attempts"`
+	ValidHops          int                 `json:"valid_hops"`
+	TargetReached      bool                `json:"target_reached"`
+	Fallback           bool                `json:"fallback"`
+	ObservedASNs       []string            `json:"observed_asns,omitempty"`
+	Classification     RouteClassification `json:"classification"`
+	Latency            RouteLatencyStats   `json:"hop_rtt"`
+	Error              string              `json:"error,omitempty"`
+}
+
+type RouteReport struct {
+	SchemaVersion string              `json:"schema_version"`
+	GeneratedAt   time.Time           `json:"generated_at"`
+	DurationMS    int64               `json:"duration_ms"`
+	Targets       []RouteTargetReport `json:"targets"`
+}
+
+type TraceFunc func(context.Context, net.IP) ([]*Hop, error)
+type AlternativeTargetFunc func(RouteTarget) []string
+
+type RouteReportConfig struct {
+	EnableIPv6        bool
+	Attempts          int
+	Timeout           time.Duration
+	Targets           []RouteTarget
+	Trace             TraceFunc
+	AlternativeTarget AlternativeTargetFunc
+}
+
+type routeAttempt struct {
+	hops     []*Hop
+	targetIP net.IP
+	fallback bool
+	err      error
+}
+
+// RunRouteReport executes the built-in China carrier return-route matrix and
+// returns deterministic structured results. ICMP traceroute response rates are
+// route evidence only and must not be interpreted as application packet loss.
+func RunRouteReport(ctx context.Context, config RouteReportConfig) RouteReport {
+	started := time.Now()
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	if config.Attempts <= 0 {
+		config.Attempts = 3
+	}
+	if config.Timeout <= 0 {
+		config.Timeout = 10 * time.Second
+	}
+	if config.Trace == nil {
+		config.Trace = TraceContext
+	}
+	usesDefaultAlternatives := config.AlternativeTarget == nil
+	if len(config.Targets) == 0 {
+		config.Targets = defaultRouteTargets(config.EnableIPv6)
+	}
+	runCtx, cancel := context.WithTimeout(ctx, config.Timeout)
+	defer cancel()
+	StartASNPrefixRefresh()
+	if usesDefaultAlternatives {
+		refreshDone := make(chan struct{})
+		go func() {
+			refreshAlternativeTargets(runCtx)
+			close(refreshDone)
+		}()
+		config.AlternativeTarget = func(target RouteTarget) []string {
+			select {
+			case <-refreshDone:
+				return defaultAlternativeTargets(target)
+			case <-runCtx.Done():
+				return nil
+			}
+		}
+	}
+	reports := make([]RouteTargetReport, len(config.Targets))
+	type indexedReport struct {
+		index  int
+		report RouteTargetReport
+	}
+	results := make(chan indexedReport, len(config.Targets))
+	for index, target := range config.Targets {
+		go func(index int, target RouteTarget) {
+			results <- indexedReport{index: index, report: runRouteTarget(runCtx, target, config)}
+		}(index, target)
+	}
+	received := make([]bool, len(config.Targets))
+	receivedCount := 0
+	for receivedCount < len(config.Targets) {
+		select {
+		case result := <-results:
+			reports[result.index] = result.report
+			if !received[result.index] {
+				received[result.index] = true
+				receivedCount++
+			}
+		case <-runCtx.Done():
+			for index, target := range config.Targets {
+				if received[index] {
+					continue
+				}
+				reports[index] = canceledRouteTarget(target, config.Attempts, runCtx.Err())
+			}
+			receivedCount = len(config.Targets)
+		}
+	}
+	return RouteReport{
+		SchemaVersion: RouteReportSchema,
+		GeneratedAt:   time.Now().UTC(),
+		DurationMS:    time.Since(started).Milliseconds(),
+		Targets:       reports,
+	}
+}
+
+func runRouteTarget(ctx context.Context, target RouteTarget, config RouteReportConfig) RouteTargetReport {
+	report := RouteTargetReport{
+		Target: target, Status: RouteProbeUnavailable, Protocol: "icmp",
+		Attempts:       config.Attempts,
+		Classification: inconclusiveClassification(strings.ToLower(normalizeCarrier(target.Carrier))+"_unknown", "线路证据不足", "no responding trace attempts"),
+	}
+	attempts := make(chan routeAttempt, config.Attempts)
+	for attempt := 0; attempt < config.Attempts; attempt++ {
+		go func() {
+			attempts <- safeExecuteRouteAttempt(ctx, target, config.Trace, config.AlternativeTarget)
+		}()
+	}
+	successful := make([]routeAttempt, 0, config.Attempts)
+	for attempt := 0; attempt < config.Attempts; attempt++ {
+		select {
+		case result := <-attempts:
+			if result.err == nil && len(result.hops) > 0 {
+				successful = append(successful, result)
+				report.Fallback = report.Fallback || result.fallback
+			}
+		case <-ctx.Done():
+			return canceledRouteTarget(target, config.Attempts, ctx.Err())
+		}
+	}
+	if len(successful) == 0 {
+		return report
+	}
+	report.Status = RouteProbeAvailable
+	report.SuccessfulAttempts = len(successful)
+	allHops := make([][]*Hop, 0, len(successful))
+	classifications := make([]RouteClassification, 0, len(successful)+1)
+	latencies := make([]float64, 0)
+	for _, attempt := range successful {
+		allHops = append(allHops, attempt.hops)
+		evidence := routeEvidenceFromHops(attempt.hops)
+		classifications = append(classifications, ClassifyReturnRoute(target.Carrier, evidence))
+		latencies = append(latencies, routeRTTMilliseconds(attempt.hops)...)
+		if routeReachedTarget(attempt.hops, attempt.targetIP) {
+			report.TargetReached = true
+		}
+	}
+	merged := mergeHops(allHops)
+	mergedEvidence := routeEvidenceFromHops(merged)
+	classifications = append(classifications, ClassifyReturnRoute(target.Carrier, mergedEvidence))
+	report.ValidHops = len(mergedEvidence)
+	report.ObservedASNs = uniqueRouteASNs(mergedEvidence)
+	report.Classification = combineRouteClassifications(target.Carrier, classifications)
+	report.Latency = calculateRouteLatency(latencies)
+	return report
+}
+
+func safeExecuteRouteAttempt(ctx context.Context, target RouteTarget, trace TraceFunc, alternatives AlternativeTargetFunc) (result routeAttempt) {
+	defer func() {
+		if recover() != nil {
+			result = routeAttempt{err: errors.New("route probe failed")}
+		}
+	}()
+	return executeRouteAttempt(ctx, target, trace, alternatives)
+}
+
+func executeRouteAttempt(ctx context.Context, target RouteTarget, trace TraceFunc, alternatives AlternativeTargetFunc) routeAttempt {
+	primary := net.ParseIP(strings.TrimSpace(target.Address))
+	if primary == nil {
+		return routeAttempt{err: errors.New("invalid route target")}
+	}
+	hops, err := trace(ctx, primary)
+	if err == nil && len(hops) > 0 {
+		return routeAttempt{hops: hops, targetIP: primary}
+	}
+	for _, value := range alternatives(target) {
+		candidate := net.ParseIP(strings.TrimSpace(value))
+		if candidate == nil || candidate.Equal(primary) {
+			continue
+		}
+		hops, err = trace(ctx, candidate)
+		if err == nil && len(hops) > 0 {
+			return routeAttempt{hops: hops, targetIP: candidate, fallback: true}
+		}
+		if ctx.Err() != nil {
+			return routeAttempt{err: ctx.Err()}
+		}
+	}
+	if err == nil {
+		err = errors.New("route returned no responding hops")
+	}
+	return routeAttempt{err: err}
+}
+
+func canceledRouteTarget(target RouteTarget, attempts int, err error) RouteTargetReport {
+	status := RouteProbeTimeout
+	message := "route probe timed out"
+	if errors.Is(err, context.Canceled) {
+		status = RouteProbeCanceled
+		message = "route probe canceled"
+	}
+	return RouteTargetReport{
+		Target: target, Status: status, Protocol: "icmp", Attempts: attempts,
+		Classification: inconclusiveClassification(strings.ToLower(normalizeCarrier(target.Carrier))+"_unknown", "线路证据不足", message),
+		Error:          message,
+	}
+}
+
+func defaultRouteTargets(enableIPv6 bool) []RouteTarget {
+	targets := make([]RouteTarget, 0, len(model.Ipv4s)+len(model.Ipv6s))
+	for index, address := range model.Ipv4s {
+		targets = append(targets, RouteTarget{
+			Name: model.Ipv4Names[index], Address: address, IPVersion: "v4", Carrier: carrierFromTargetName(model.Ipv4Names[index]),
+		})
+	}
+	if enableIPv6 {
+		for index, address := range model.Ipv6s {
+			targets = append(targets, RouteTarget{
+				Name: model.Ipv6Names[index], Address: address, IPVersion: "v6", Carrier: carrierFromTargetName(model.Ipv6Names[index]),
+			})
+		}
+	}
+	return targets
+}
+
+func carrierFromTargetName(name string) string {
+	switch {
+	case strings.Contains(name, "电信"):
+		return "CT"
+	case strings.Contains(name, "联通"):
+		return "CU"
+	case strings.Contains(name, "移动"):
+		return "CM"
+	default:
+		return ""
+	}
+}
+
+func routeEvidenceFromHops(hops []*Hop) []RouteHopEvidence {
+	result := make([]RouteHopEvidence, 0, len(hops))
+	for _, hop := range hops {
+		if hop == nil || len(hop.Nodes) == 0 {
+			continue
+		}
+		seen := make(map[string]struct{})
+		asns := make([]string, 0, len(hop.Nodes))
+		for _, node := range hop.Nodes {
+			if node == nil || node.IP == nil {
+				continue
+			}
+			asn := ipv4Asn(node.IP.String())
+			if asn == "" {
+				continue
+			}
+			if _, exists := seen[asn]; exists {
+				continue
+			}
+			seen[asn] = struct{}{}
+			asns = append(asns, asn)
+		}
+		result = append(result, RouteHopEvidence{Distance: hop.Distance, ASNs: asns})
+	}
+	return result
+}
+
+func uniqueRouteASNs(hops []RouteHopEvidence) []string {
+	seen := make(map[string]struct{})
+	result := make([]string, 0)
+	for _, hop := range hops {
+		for _, asn := range hop.ASNs {
+			if _, exists := seen[asn]; exists {
+				continue
+			}
+			seen[asn] = struct{}{}
+			result = append(result, asn)
+		}
+	}
+	return result
+}
+
+func routeRTTMilliseconds(hops []*Hop) []float64 {
+	result := make([]float64, 0)
+	for _, hop := range hops {
+		if hop == nil {
+			continue
+		}
+		for _, node := range hop.Nodes {
+			if node == nil {
+				continue
+			}
+			for _, value := range node.RTT {
+				if value >= 0 {
+					result = append(result, float64(value)/float64(time.Millisecond))
+				}
+			}
+		}
+	}
+	return result
+}
+
+func calculateRouteLatency(values []float64) RouteLatencyStats {
+	if len(values) == 0 {
+		return RouteLatencyStats{}
+	}
+	ordered := append([]float64(nil), values...)
+	sort.Float64s(ordered)
+	total := 0.0
+	for _, value := range values {
+		total += value
+	}
+	jitter := 0.0
+	if len(values) > 1 {
+		for index := 1; index < len(values); index++ {
+			delta := values[index] - values[index-1]
+			if delta < 0 {
+				delta = -delta
+			}
+			jitter += delta
+		}
+		jitter /= float64(len(values) - 1)
+	}
+	return RouteLatencyStats{
+		Samples: len(values), MinMS: ordered[0], AvgMS: total / float64(len(values)),
+		P50MS: ordered[percentileIndex(len(ordered), 0.50)], P95MS: ordered[percentileIndex(len(ordered), 0.95)],
+		MaxMS: ordered[len(ordered)-1], JitterMS: jitter,
+	}
+}
+
+func percentileIndex(length int, percentile float64) int {
+	if length <= 1 {
+		return 0
+	}
+	index := int(math.Ceil(float64(length)*percentile)) - 1
+	if index < 0 {
+		return 0
+	}
+	if index >= length {
+		return length - 1
+	}
+	return index
+}
+
+func routeReachedTarget(hops []*Hop, target net.IP) bool {
+	if target == nil {
+		return false
+	}
+	for _, hop := range hops {
+		if hop == nil {
+			continue
+		}
+		for _, node := range hop.Nodes {
+			if node != nil && node.IP != nil && node.IP.Equal(target) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+var alternativeRefreshMu sync.Mutex
+
+func refreshAlternativeTargets(ctx context.Context) {
+	alternativeRefreshMu.Lock()
+	defer alternativeRefreshMu.Unlock()
+	if model.CachedIcmpData != "" && model.ParsedIcmpTargets != nil && time.Since(model.CachedIcmpDataFetchTime) <= time.Hour {
+		return
+	}
+	data := getDataContext(ctx, model.IcmpTargets)
+	if data == "" {
+		return
+	}
+	parsed := parseIcmpTargets(data)
+	if len(parsed) == 0 {
+		return
+	}
+	model.CachedIcmpData = data
+	model.ParsedIcmpTargets = parsed
+	model.CachedIcmpDataFetchTime = time.Now()
+}
+
+func defaultAlternativeTargets(target RouteTarget) []string {
+	return tryAlternativeIPs(target.Name, target.IPVersion)
+}
--- a/bk/route_report_test.go
+++ b/bk/route_report_test.go
@ -0,0 +1,132 @@
+package backtrace
+
+import (
+	"context"
+	"net"
+	"regexp"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/oneclickvirt/backtrace/model"
+)
+
+func testHop(distance int, ip string, rtt time.Duration) *Hop {
+	return &Hop{Distance: distance, Nodes: []*Node{{IP: net.ParseIP(ip), RTT: []time.Duration{rtt}}}}
+}
+
+func TestRunRouteReportOfflineFixture(t *testing.T) {
+	report := RunRouteReport(context.Background(), RouteReportConfig{
+		Attempts: 2,
+		Timeout:  time.Second,
+		Targets:  []RouteTarget{{Name: "测试电信v4", Address: "192.0.2.1", IPVersion: "v4", Carrier: "CT"}},
+		Trace: func(_ context.Context, _ net.IP) ([]*Hop, error) {
+			return []*Hop{
+				testHop(1, "59.43.1.1", 10*time.Millisecond),
+				testHop(2, "59.43.2.2", 20*time.Millisecond),
+				testHop(3, "202.97.1.1", 30*time.Millisecond),
+			}, nil
+		},
+		AlternativeTarget: func(RouteTarget) []string { return nil },
+	})
+	if report.SchemaVersion != RouteReportSchema || len(report.Targets) != 1 {
+		t.Fatalf("unexpected report: %+v", report)
+	}
+	target := report.Targets[0]
+	if target.Status != RouteProbeAvailable || target.SuccessfulAttempts != 2 || target.ValidHops != 3 {
+		t.Fatalf("unexpected target status: %+v", target)
+	}
+	if target.Classification.Code != "ct_cn2_gia" || target.Latency.Samples != 6 || target.Latency.P95MS != 30 {
+		t.Fatalf("unexpected route classification or latency: %+v", target)
+	}
+	if strings.Contains(RenderRouteReport(report), "P95") || !strings.Contains(RenderRouteReport(report), "电信CN2GIA") {
+		t.Fatalf("legacy rendering is not compact: %q", RenderRouteReport(report))
+	}
+}
+
+func TestRunRouteReportUsesAlternativeWithoutExposingItsAddress(t *testing.T) {
+	report := RunRouteReport(context.Background(), RouteReportConfig{
+		Attempts: 1,
+		Timeout:  time.Second,
+		Targets:  []RouteTarget{{Name: "测试联通v4", Address: "192.0.2.1", IPVersion: "v4", Carrier: "CU"}},
+		Trace: func(_ context.Context, ip net.IP) ([]*Hop, error) {
+			if ip.Equal(net.ParseIP("198.51.100.2")) {
+				return []*Hop{testHop(1, "202.77.1.1", 12*time.Millisecond)}, nil
+			}
+			return nil, nil
+		},
+		AlternativeTarget: func(RouteTarget) []string { return []string{"198.51.100.2"} },
+	})
+	target := report.Targets[0]
+	if !target.Fallback || target.Classification.Code != "cu_cug" {
+		t.Fatalf("alternative result = %+v", target)
+	}
+	if strings.Contains(RenderRouteReport(report), "198.51.100.2") {
+		t.Fatalf("legacy output exposed fallback target: %q", RenderRouteReport(report))
+	}
+}
+
+func TestRenderRouteReportPreservesLegacyAddressWidths(t *testing.T) {
+	report := RouteReport{Targets: []RouteTargetReport{
+		{
+			Target:         RouteTarget{Name: "北京电信v4", Address: "219.141.140.10", IPVersion: "v4", Carrier: "CT"},
+			Status:         RouteProbeAvailable,
+			Classification: RouteClassification{Label: "电信163    [普通线路]", Confidence: routeConfidenceConfirmed, Rank: 2},
+		},
+		{
+			Target:         RouteTarget{Name: "北京电信v6", Address: "2400:89c0:1053:3::69", IPVersion: "v6", Carrier: "CT"},
+			Status:         RouteProbeAvailable,
+			Classification: RouteClassification{Label: "电信163    [普通线路]", Confidence: routeConfidenceConfirmed, Rank: 2},
+		},
+	}}
+	rendered := regexp.MustCompile(`\x1b\[[0-9;]*m`).ReplaceAllString(RenderRouteReport(report), "")
+	if !strings.Contains(rendered, "北京电信v4 219.141.140.10  电信163") {
+		t.Fatalf("IPv4 legacy spacing changed: %q", rendered)
+	}
+	if !strings.Contains(rendered, "北京电信v6 2400:89c0:1053:3::69     电信163") {
+		t.Fatalf("IPv6 legacy spacing changed: %q", rendered)
+	}
+}
+
+func TestRunRouteReportHonorsContext(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	report := RunRouteReport(ctx, RouteReportConfig{
+		Attempts:          1,
+		Targets:           []RouteTarget{{Name: "测试移动v4", Address: "192.0.2.1", IPVersion: "v4", Carrier: "CM"}},
+		Trace:             func(ctx context.Context, _ net.IP) ([]*Hop, error) { return nil, ctx.Err() },
+		AlternativeTarget: func(RouteTarget) []string { return nil },
+	})
+	if report.Targets[0].Status != RouteProbeCanceled {
+		t.Fatalf("canceled report = %+v", report.Targets[0])
+	}
+}
+
+func TestRefreshAlternativeTargetsHonorsCanceledContextAndKeepsValidCache(t *testing.T) {
+	alternativeRefreshMu.Lock()
+	oldData := model.CachedIcmpData
+	oldTargets := model.ParsedIcmpTargets
+	oldFetchedAt := model.CachedIcmpDataFetchTime
+	model.CachedIcmpData = `[{"province":"北京","isp":"电信","ip_version":"v4","ips":"192.0.2.10"}]`
+	model.ParsedIcmpTargets = []model.IcmpTarget{{Province: "北京", ISP: "电信", IPVersion: "v4", IPs: "192.0.2.10"}}
+	model.CachedIcmpDataFetchTime = time.Now().Add(-2 * time.Hour)
+	alternativeRefreshMu.Unlock()
+	t.Cleanup(func() {
+		alternativeRefreshMu.Lock()
+		defer alternativeRefreshMu.Unlock()
+		model.CachedIcmpData = oldData
+		model.ParsedIcmpTargets = oldTargets
+		model.CachedIcmpDataFetchTime = oldFetchedAt
+	})
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	started := time.Now()
+	refreshAlternativeTargets(ctx)
+	if elapsed := time.Since(started); elapsed > 250*time.Millisecond {
+		t.Fatalf("canceled refresh took %s", elapsed)
+	}
+	if model.CachedIcmpData == "" || len(model.ParsedIcmpTargets) != 1 {
+		t.Fatalf("failed refresh replaced valid cache: data=%q targets=%v", model.CachedIcmpData, model.ParsedIcmpTargets)
+	}
+}
--- a/bk/trace_common.go
+++ b/bk/trace_common.go
@ -544,6 +544,15 @@ func (h *Hop) Add(r *Reply) *Node {

 // Trace is a simple traceroute tool using DefaultTracer.
 func Trace(ip net.IP) ([]*Hop, error) {
+	return TraceContext(context.Background(), ip)
+}
+
+// TraceContext runs an ICMP traceroute that stops promptly when the caller's
+// context is canceled.
+func TraceContext(ctx context.Context, ip net.IP) ([]*Hop, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
 	hops := make([]*Hop, 0, DefaultTracer.MaxHops)
 	touch := func(dist int) *Hop {
 		for _, h := range hops {
@ -555,7 +564,7 @@ func Trace(ip net.IP) ([]*Hop, error) {
 		hops = append(hops, h)
 		return h
 	}
-	err := DefaultTracer.Trace(context.Background(), ip, func(r *Reply) {
+	err := DefaultTracer.Trace(ctx, ip, func(r *Reply) {
 		touch(r.Hops).Add(r)
 	})
 	if err != nil && err != context.DeadlineExceeded {
--- a/bk/utils.go
+++ b/bk/utils.go
@ -1,6 +1,7 @@
 package backtrace

 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@ -35,32 +36,43 @@ func removeDuplicates(elements []string) []string {

 // checkCdn 检查CDN可用性，参考shell脚本的测试逻辑
 func checkCdn(testUrl string) string {
+	return checkCdnContext(context.Background(), testUrl)
+}
+
+func checkCdnContext(ctx context.Context, testUrl string) string {
+	if ctx == nil {
+		ctx = context.Background()
+	}
 	client := req.C()
 	client.SetTimeout(6 * time.Second)
 	if model.EnableLoger {
 		InitLogger()
 		defer Logger.Sync()
 	}
-	for _, cdnUrl := range model.CdnList {
+	for index, cdnUrl := range model.CdnList {
 		url := cdnUrl + testUrl
 		if model.EnableLoger {
-			Logger.Info(fmt.Sprintf("Testing CDN: %s", url))
+			Logger.Info(fmt.Sprintf("Testing CDN source %d", index+1))
 		}
-		resp, err := client.R().Get(url)
+		resp, err := client.R().SetContext(ctx).Get(url)
 		if err == nil && resp != nil && resp.Body != nil {
 			b, err := io.ReadAll(resp.Body)
 			resp.Body.Close()
 			if err == nil && strings.Contains(string(b), "success") {
 				if model.EnableLoger {
-					Logger.Info(fmt.Sprintf("CDN available: %s", cdnUrl))
+					Logger.Info(fmt.Sprintf("CDN source %d available", index+1))
 				}
 				return cdnUrl
 			}
 		}
 		if model.EnableLoger {
-			Logger.Info(fmt.Sprintf("CDN test failed: %s, error: %v", cdnUrl, err))
+			Logger.Info(fmt.Sprintf("CDN source %d unavailable", index+1))
+		}
+		select {
+		case <-ctx.Done():
+			return ""
+		case <-time.After(500 * time.Millisecond):
 		}
-		time.Sleep(500 * time.Millisecond)
 	}
 	if model.EnableLoger {
 		Logger.Info("No CDN available, using direct connection")
@ -70,12 +82,15 @@ func checkCdn(testUrl string) string {

 // getData 获取目标地址的文本内容
 func getData(endpoint string) string {
+	return getDataContext(context.Background(), endpoint)
+}
+
+func getDataContext(ctx context.Context, endpoint string) string {
+	if ctx == nil {
+		ctx = context.Background()
+	}
 	client := req.C()
 	client.SetTimeout(6 * time.Second)
-	client.R().
-		SetRetryCount(2).
-		SetRetryBackoffInterval(1*time.Second, 5*time.Second).
-		SetRetryFixedInterval(2 * time.Second)
 	if model.EnableLoger {
 		InitLogger()
 		defer Logger.Sync()
@ -83,15 +98,19 @@ func getData(endpoint string) string {

 	// 先测试CDN可用性
 	testUrl := "https://raw.githubusercontent.com/spiritLHLS/ecs/main/back/test"
-	cdnUrl := checkCdn(testUrl)
+	cdnUrl := checkCdnContext(ctx, testUrl)

 	// 如果有可用的CDN，使用CDN获取数据
 	if cdnUrl != "" {
 		url := cdnUrl + endpoint
 		if model.EnableLoger {
-			Logger.Info(fmt.Sprintf("Using CDN: %s", url))
+			Logger.Info("Using validated CDN source")
 		}
-		resp, err := client.R().Get(url)
+		resp, err := client.R().
+			SetContext(ctx).
+			SetRetryCount(2).
+			SetRetryFixedInterval(2 * time.Second).
+			Get(url)
 		if err == nil && resp != nil && resp.Body != nil {
 			defer resp.Body.Close()
 			b, err := io.ReadAll(resp.Body)
@ -103,15 +122,19 @@ func getData(endpoint string) string {
 			}
 		}
 		if model.EnableLoger {
-			Logger.Info(fmt.Sprintf("CDN request failed: %v", err))
+			Logger.Info("CDN data request failed")
 		}
 	}

 	// CDN不可用，尝试直连
 	if model.EnableLoger {
-		Logger.Info(fmt.Sprintf("Trying direct connection: %s", endpoint))
+		Logger.Info("Trying direct data source")
 	}
-	resp, err := client.R().Get(endpoint)
+	resp, err := client.R().
+		SetContext(ctx).
+		SetRetryCount(2).
+		SetRetryFixedInterval(2 * time.Second).
+		Get(endpoint)
 	if err == nil && resp != nil && resp.Body != nil {
 		defer resp.Body.Close()
 		b, err := io.ReadAll(resp.Body)
@ -123,7 +146,7 @@ func getData(endpoint string) string {
 		}
 	}
 	if model.EnableLoger {
-		Logger.Info(fmt.Sprintf("Direct connection failed: %v", err))
+		Logger.Info("Direct data request failed")
 	}
 	return ""
 }
--- a/cmd/main.go
+++ b/cmd/main.go
@ -40,7 +40,9 @@ type cliOptions struct {
 	help        bool
 	ipv6        bool
 	jsonOutput  bool
+	routeJSON   bool
 	deep        bool
+	routeTries  int
 	specifiedIP string
 	timeout     time.Duration
 }
@ -55,8 +57,10 @@ func newBacktraceFlagSet(options *cliOptions) *flag.FlagSet {
 	set.StringVar(&options.specifiedIP, "ip", "", "Specify IP address for bgptools")
 	set.BoolVar(&options.jsonOutput, "json", false, "Output structured RDAP/BGP report as JSON")
 	set.BoolVar(&options.jsonOutput, "structured", false, "Alias for -json")
+	set.BoolVar(&options.routeJSON, "route-json", false, "Output structured return-route report as JSON")
 	set.BoolVar(&options.deep, "deep", false, "Fetch geofeed and enable WHOIS fallback")
-	set.DurationVar(&options.timeout, "timeout", 15*time.Second, "Structured report timeout")
+	set.IntVar(&options.routeTries, "route-attempts", 3, "Traceroute attempts per target (1-5)")
+	set.DurationVar(&options.timeout, "timeout", 15*time.Second, "Structured or route report timeout")
 	return set
 }

@ -83,7 +87,7 @@ func main() {
 	if err := backtraceFlag.Parse(os.Args[1:]); err != nil {
 		os.Exit(2)
 	}
-	if !options.jsonOutput {
+	if !options.jsonOutput && !options.routeJSON {
 		fmt.Println(Green("Repo:"), Yellow("https://github.com/oneclickvirt/backtrace"))
 	}
 	if options.help {
@ -114,6 +118,18 @@ func main() {
 		}
 		return
 	}
+	if options.routeJSON {
+		report := backtrace.RunRouteReport(context.Background(), backtrace.RouteReportConfig{
+			EnableIPv6: options.ipv6,
+			Attempts:   options.routeTries,
+			Timeout:    options.timeout,
+		})
+		if err := writeStructuredRouteReport(os.Stdout, report); err != nil {
+			fmt.Fprintf(os.Stderr, "route report failed: %s\n", sanitizeErrorText(err.Error()))
+			os.Exit(1)
+		}
+		return
+	}
 	info := IpInfo{}
 	if options.showIPInfo {
 		rsp, err := http.Get("http://ipinfo.io")
@ -200,9 +216,21 @@ func main() {
 }

 func validateStructuredOptions(options cliOptions) error {
+	if options.jsonOutput && options.routeJSON {
+		return fmt.Errorf("-json and -route-json are mutually exclusive")
+	}
 	if options.deep && !options.jsonOutput {
 		return fmt.Errorf("-deep requires -json or -structured")
 	}
+	if options.routeJSON {
+		if options.timeout <= 0 {
+			return fmt.Errorf("route report timeout must be positive")
+		}
+		if options.routeTries < 1 || options.routeTries > 5 {
+			return fmt.Errorf("route attempts must be between 1 and 5")
+		}
+		return nil
+	}
 	if !options.jsonOutput {
 		return nil
 	}
@ -215,6 +243,12 @@ func validateStructuredOptions(options cliOptions) error {
 	return nil
 }

+func writeStructuredRouteReport(output io.Writer, report backtrace.RouteReport) error {
+	encoder := json.NewEncoder(output)
+	encoder.SetIndent("", "  ")
+	return encoder.Encode(report)
+}
+
 func writeStructuredReport(ctx context.Context, output io.Writer, ip string, config bgptools.IPBGPReportConfig, query func(context.Context, string, bgptools.IPBGPReportConfig) (*bgptools.IPBGPReport, error)) error {
 	report, err := query(ctx, ip, config)
 	if err != nil {
--- a/cmd/main_test.go
+++ b/cmd/main_test.go
@ -8,6 +8,7 @@ import (
 	"time"

 	"github.com/oneclickvirt/backtrace/bgptools"
+	backtrace "github.com/oneclickvirt/backtrace/bk"
 )

 func TestBacktraceStructuredFlagParsing(t *testing.T) {
@ -26,11 +27,53 @@ func TestBacktraceDefaultsPreserveLegacyMode(t *testing.T) {
 	if err := newBacktraceFlagSet(&options).Parse(nil); err != nil {
 		t.Fatal(err)
 	}
-	if !options.showIPInfo || options.jsonOutput || options.deep || options.ipv6 || options.specifiedIP != "" || options.timeout != 15*time.Second {
+	if !options.showIPInfo || options.jsonOutput || options.routeJSON || options.deep || options.ipv6 || options.specifiedIP != "" || options.timeout != 15*time.Second || options.routeTries != 3 {
 		t.Fatalf("legacy defaults changed: %+v", options)
 	}
 }

+func TestBacktraceRouteStructuredFlagParsing(t *testing.T) {
+	var options cliOptions
+	set := newBacktraceFlagSet(&options)
+	if err := set.Parse([]string{"-route-json", "-ipv6", "-route-attempts", "4", "-timeout", "9s"}); err != nil {
+		t.Fatal(err)
+	}
+	if !options.routeJSON || !options.ipv6 || options.routeTries != 4 || options.timeout != 9*time.Second {
+		t.Fatalf("unexpected route options: %+v", options)
+	}
+	if err := validateStructuredOptions(options); err != nil {
+		t.Fatalf("valid route options rejected: %v", err)
+	}
+}
+
+func TestValidateRouteStructuredOptions(t *testing.T) {
+	for _, options := range []cliOptions{
+		{jsonOutput: true, routeJSON: true, timeout: time.Second, routeTries: 3},
+		{routeJSON: true, timeout: 0, routeTries: 3},
+		{routeJSON: true, timeout: time.Second, routeTries: 0},
+		{routeJSON: true, timeout: time.Second, routeTries: 6},
+	} {
+		if err := validateStructuredOptions(options); err == nil {
+			t.Fatalf("expected invalid route options: %+v", options)
+		}
+	}
+}
+
+func TestWriteStructuredRouteReportKeepsStdoutJSONOnly(t *testing.T) {
+	var output bytes.Buffer
+	report := backtrace.RouteReport{SchemaVersion: backtrace.RouteReportSchema, Targets: []backtrace.RouteTargetReport{}}
+	if err := writeStructuredRouteReport(&output, report); err != nil {
+		t.Fatal(err)
+	}
+	var decoded backtrace.RouteReport
+	if err := json.Unmarshal(output.Bytes(), &decoded); err != nil {
+		t.Fatalf("stdout is not route JSON: %v (%q)", err, output.String())
+	}
+	if decoded.SchemaVersion != backtrace.RouteReportSchema {
+		t.Fatalf("unexpected route report: %+v", decoded)
+	}
+}
+
 func TestValidateStructuredOptionsRequiresExplicitModeAndTarget(t *testing.T) {
 	tests := []cliOptions{
 		{deep: true, timeout: time.Second},
--- a/cmd/update-prefixes/main.go
+++ b/cmd/update-prefixes/main.go
@ -20,7 +20,7 @@ import (
 	"time"
 )

-var knownASNs = []string{"AS23764", "AS4134", "AS4809", "AS4837", "AS58453", "AS58807", "AS9808", "AS9929"}
+var knownASNs = []string{"AS10099", "AS23764", "AS4134", "AS4809", "AS4837", "AS58453", "AS58807", "AS9808", "AS9929"}
 var errPrefixCountDrop = errors.New("prefix count dropped beyond protection threshold")

 type updateConfig struct {
--- a/model/model.go
+++ b/model/model.go
@ -2,7 +2,7 @@ package model

 import "time"

-const BackTraceVersion = "v0.0.17"
+const BackTraceVersion = "v0.0.18"

 var EnableLoger = false

@ -68,6 +68,7 @@ var (
 		"AS4809":  "电信CN2    [优质线路]",
 		"AS4134":  "电信163    [普通线路]",
 		"AS9929":  "联通9929   [优质线路]",
+		"AS10099": "联通CUG    [优质线路]",
 		"AS4837":  "联通4837   [普通线路]",
 		"AS58807": "移动CMIN2  [精品线路]",
 		"AS9808":  "移动CMI    [普通线路]",