fix(link): restore mKCP seed and headerType on share-link import (#6480)

* fix(link): restore mKCP seed and headerType on share-link import applyTransport / applyTransportParams ignored kcp query params that applyKcpShareParams emits, so re-imported outbounds lost seed and header and could not talk to the inbound. Mirror those fields (plus mtu/tti) into kcpSettings in both Go and TS importers. Fixes #6476 * fix(link): restore mKCP header/seed via finalmask mkcp-legacy * fix(link): split mKCP header and seed into separate masks on import Both importers folded a share link's headerType and seed into one mkcp-legacy mask {header, value}. xray-core's MkcpLegacy.Build ignores value once header is set (and reads it as the fake DNS domain for header=dns), so an imported outbound carried the header mask but no AES-128-GCM seed while the emitting inbound has both, and could not connect — the failure #6476 reports, now for every link carrying both params. Emit one mask per field, seed first: the finalmask array's first item is the innermost layer, which puts the header around the cipher as legacy mKCP did. Also bound mtu/tti to KCPConfig.Build's accepted ranges (mtu >= 21, tti 10..1000, decimal digits only on both importers) so a pasted link cannot fail the whole Xray config load, and look header types up as own properties so a prototype key such as "constructor" is not mapped. --------- Co-authored-by: mrchatam <287639636+mrchatam@users.noreply.github.com> Co-authored-by: Sanaei <ho3ein.sanaei@gmail.com>
2026-09-16 15:17:14 +00:00 · 2026-09-13 23:58:13 +03:30
parent 939c470698
commit 5ad9df69b9
4 changed files with 299 additions and 8 deletions
@@ -704,6 +704,15 @@ func applyTransport(stream map[string]any, p url.Values) {
 				xh[k] = v
 			}
 		}
+	case "kcp":
+		// mtu/tti live on kcpSettings; header/seed are finalmask mkcp-legacy (see applyMkcpLegacyFromShare).
+		kcp := stream["kcpSettings"].(map[string]any)
+		if n, ok := kcpParamInRange(p.Get("mtu"), kcpMinMTU, kcpMaxMTU); ok {
+			kcp["mtu"] = n
+		}
+		if n, ok := kcpParamInRange(p.Get("tti"), kcpMinTTI, kcpMaxTTI); ok {
+			kcp["tti"] = n
+		}
 	case "tcp":
 		if p.Get("headerType") == "http" || p.Get("type") == "http" {
 			stream["tcpSettings"] = map[string]any{
@@ -753,6 +762,87 @@ func applyFinalMask(stream map[string]any, p url.Values) {
 			stream["finalmask"] = parsed
 		}
 	}
+	applyMkcpLegacyFromShare(stream, p)
+}
+
+// mKCP bounds mirror xray-core's KCPConfig.Build checks (a value outside them fails
+// the whole config load); mtu's ceiling is the int32 that fits its uint32 field everywhere.
+const (
+	kcpMinMTU = 21
+	kcpMaxMTU = math.MaxInt32
+	kcpMinTTI = 10
+	kcpMaxTTI = 1000
+)
+
+// kcpParamInRange rejects an out-of-range or malformed link value so buildStream's default stays.
+func kcpParamInRange(s string, minVal, maxVal int) (int, bool) {
+	n, err := strconv.Atoi(s)
+	return n, err == nil && n >= minVal && n <= maxVal
+}
+
+// kcpHeaderTypeToMask maps share-link headerType to mkcp-legacy settings.header
+// (inverse of sub.kcpMaskToHeaderType).
+var kcpHeaderTypeToMask = map[string]string{
+	"dns":          "dns",
+	"dtls":         "dtls",
+	"srtp":         "srtp",
+	"utp":          "utp",
+	"wechat-video": "wechat",
+	"wireguard":    "wireguard",
+}
+
+// applyMkcpLegacyFromShare restores headerType/seed into finalmask.udp mkcp-legacy,
+// matching the shape InboundFormModal / FinalMaskForm emit. fm= mkcp-legacy wins.
+func applyMkcpLegacyFromShare(stream map[string]any, p url.Values) {
+	headerType := strings.TrimSpace(p.Get("headerType"))
+	seed := p.Get("seed")
+	if headerType == "" || headerType == "none" {
+		headerType = ""
+	}
+	if headerType == "" && seed == "" {
+		return
+	}
+	if network, _ := stream["network"].(string); network != "" && network != "kcp" {
+		return
+	}
+	maskHeader := ""
+	if headerType != "" {
+		mapped, ok := kcpHeaderTypeToMask[headerType]
+		if !ok {
+			return
+		}
+		maskHeader = mapped
+	}
+	finalmask, _ := stream["finalmask"].(map[string]any)
+	if finalmask == nil {
+		finalmask = map[string]any{}
+	}
+	udp, _ := finalmask["udp"].([]any)
+	for _, raw := range udp {
+		m, _ := raw.(map[string]any)
+		if m != nil {
+			if t, _ := m["type"].(string); t == "mkcp-legacy" {
+				return // fm= (or prior) already carries the live mask
+			}
+		}
+	}
+	// One mask per field, seed first: MkcpLegacy.Build ignores value once header is set,
+	// and the chain puts the last mask outermost on the wire (header around the cipher).
+	if seed != "" {
+		udp = append(udp, mkcpLegacyMask("", seed))
+	}
+	if maskHeader != "" {
+		udp = append(udp, mkcpLegacyMask(maskHeader, ""))
+	}
+	finalmask["udp"] = udp
+	stream["finalmask"] = finalmask
+}
+
+func mkcpLegacyMask(header, value string) map[string]any {
+	return map[string]any{
+		"type":     "mkcp-legacy",
+		"settings": map[string]any{"header": header, "value": value},
+	}
 }

 // gecko packetSize bounds mirror xray-core's salamander buffer cap.
@@ -4,6 +4,7 @@ import (
 	"encoding/base64"
 	"net/url"
 	"reflect"
+	"slices"
 	"testing"
 )

@@ -244,3 +245,76 @@ func TestParseTrojanAndSS_CoreFields(t *testing.T) {
 		t.Errorf("ss server = %#v", ssrv)
 	}
 }
+
+type mkcpMask struct{ header, value string }
+
+func mkcpLegacyMasks(t *testing.T, res *ParseResult) []mkcpMask {
+	t.Helper()
+	var out []mkcpMask
+	for _, raw := range finalmaskUDP(t, res) {
+		mask, _ := raw.(map[string]any)
+		if mask["type"] != "mkcp-legacy" {
+			t.Fatalf("unexpected udp mask %#v", mask)
+		}
+		settings, _ := mask["settings"].(map[string]any)
+		header, _ := settings["header"].(string)
+		value, _ := settings["value"].(string)
+		out = append(out, mkcpMask{header, value})
+	}
+	return out
+}
+
+func TestParse_KcpShareParams(t *testing.T) {
+	// The emitter flattens one mkcp-legacy mask per field into headerType/seed; a merged
+	// mask drops the seed in xray-core (MkcpLegacy.Build), so import rebuilds them separately.
+	cases := []struct {
+		name      string
+		link      string
+		wantMTU   int
+		wantTTI   int
+		wantMasks []mkcpMask
+	}{
+		{
+			name:      "vless header and seed become two masks, seed first",
+			link:      "vless://uuid@h.com:443?type=kcp&headerType=wechat-video&seed=secret-seed&mtu=1400&tti=50&security=none#kcp1",
+			wantMTU:   1400,
+			wantTTI:   50,
+			wantMasks: []mkcpMask{{"", "secret-seed"}, {"wechat", ""}},
+		},
+		{
+			name:      "trojan header only adds no seed mask",
+			link:      "trojan://pw@h.com:443?type=kcp&headerType=srtp&security=none#kcp-tj",
+			wantMTU:   1350,
+			wantTTI:   20,
+			wantMasks: []mkcpMask{{"srtp", ""}},
+		},
+		{
+			name:      "seed only adds no header mask",
+			link:      "vless://uuid@h.com:443?type=kcp&headerType=none&seed=abc123&security=none",
+			wantMTU:   1350,
+			wantTTI:   20,
+			wantMasks: []mkcpMask{{"", "abc123"}},
+		},
+		{
+			name:    "mtu/tti outside KCPConfig.Build bounds keep the defaults",
+			link:    "vless://uuid@h.com:443?type=kcp&mtu=10&tti=5000&security=none",
+			wantMTU: 1350,
+			wantTTI: 20,
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			res, err := ParseLink(c.link)
+			if err != nil {
+				t.Fatalf("parse: %v", err)
+			}
+			kcp := streamSub(t, res, "kcpSettings")
+			if kcp["mtu"] != c.wantMTU || kcp["tti"] != c.wantTTI {
+				t.Fatalf("kcpSettings mtu/tti = %v/%v, want %d/%d", kcp["mtu"], kcp["tti"], c.wantMTU, c.wantTTI)
+			}
+			if got := mkcpLegacyMasks(t, res); !slices.Equal(got, c.wantMasks) {
+				t.Fatalf("mkcp-legacy masks = %v, want %v", got, c.wantMasks)
+			}
+		})
+	}
+}