feat(sub): warn when salamander settings cannot reach the client (#6177)

* feat(sub): warn when salamander settings cannot reach the client

A hysteria2 share link carries obfuscation as obfs=salamander plus
obfs-password, and nothing else. Xray's finalmask accepts more than that —
packetSize among them — and those extra settings change what the server expects
on the wire. The emitted URI then looks complete but describes a server the
client cannot reach: every standard client applies plain salamander, the server
drops the packets, and the failure is silent on both ends.

Log the unexpressible keys when building such a link, naming the inbound, so the
cause is visible instead of appearing as a client-side problem.

* fix(sub): deduplicate salamander warnings

internal/sub/salamander_uri_test.go

@@ -0,0 +1,55 @@
+package sub
+
+import (
+	"reflect"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
+	"github.com/mhsanaei/3x-ui/v3/internal/logger"
+)
+
+func TestExtraSalamanderKeys(t *testing.T) {
+	if got := extraSalamanderKeys(map[string]any{"password": "pw"}); len(got) != 0 {
+		t.Fatalf("expressible settings reported extras: %v", got)
+	}
+	got := extraSalamanderKeys(map[string]any{"password": "pw", "packetSize": "512-1200"})
+	if want := []string{"packetSize"}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("extraSalamanderKeys = %v, want %v", got, want)
+	}
+}
+
+func TestGenHysteriaLinkWarnsOnceForUnsupportedSalamanderSettings(t *testing.T) {
+	makeInbound := func(id int, settings string) *model.Inbound {
+		return &model.Inbound{
+			Id: id, Listen: "203.0.113.1", Port: 443, Protocol: model.Hysteria,
+			Settings:       `{"version":2,"clients":[{"auth":"secret","email":"user"}]}`,
+			StreamSettings: `{"security":"tls","finalmask":{"udp":[{"type":"salamander","settings":` + settings + `}]}}`,
+		}
+	}
+	countWarnings := func(id int) int {
+		needle := "inbound " + strconv.Itoa(id) + ": salamander settings"
+		count := 0
+		for _, line := range logger.GetLogs(100, "warning") {
+			if strings.Contains(line, needle) {
+				count++
+			}
+		}
+		return count
+	}
+
+	const standardID = 910001
+	(&SubService{}).genHysteriaLink(makeInbound(standardID, `{"password":"pw"}`), "user")
+	if got := countWarnings(standardID); got != 0 {
+		t.Fatalf("password-only warning count = %d, want 0", got)
+	}
+
+	const unsupportedID = 910002
+	in := makeInbound(unsupportedID, `{"password":"pw","packetSize":"512-1200"}`)
+	(&SubService{}).genHysteriaLink(in, "user")
+	(&SubService{}).genHysteriaLink(in, "user")
+	if got := countWarnings(unsupportedID); got != 1 {
+		t.Fatalf("unsupported-settings warning count = %d, want 1", got)
+	}
+}

internal/sub/service.go

@@ -9,8 +9,10 @@ import (
 	"net"
 	"net/url"
 	"slices"
+	"sort"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/gin-gonic/gin"
@@ -26,6 +28,8 @@ import (
 	"github.com/mhsanaei/3x-ui/v3/internal/xray"
 )
 
+var salamanderWarningSeen sync.Map
+
 // SubService provides business logic for generating subscription links and managing subscription data.
 type SubService struct {
 	address        string
@@ -1051,6 +1055,12 @@ func (s *SubService) genHysteriaLink(inbound *model.Inbound, email string) strin
 				}
 				settings, _ := mask["settings"].(map[string]any)
 				if pw, ok := settings["password"].(string); ok && pw != "" {
+					if extra := extraSalamanderKeys(settings); len(extra) > 0 {
+						warningKey := fmt.Sprintf("%d:%v", inbound.Id, extra)
+						if _, loaded := salamanderWarningSeen.LoadOrStore(warningKey, struct{}{}); !loaded {
+							logger.Warningf("SubService - inbound %d: salamander settings %v cannot be expressed in a hysteria2 URI; standard clients will fail the handshake", inbound.Id, extra)
+						}
+					}
 					params["obfs"] = "salamander"
 					params["obfs-password"] = pw
 					break
@@ -2696,3 +2706,16 @@ func getHostFromXFH(s string) (string, error) {
 	}
 	return s, nil
 }
+
+// extraSalamanderKeys lists salamander settings the hysteria2 URI cannot carry.
+// A server using them rejects every client built from the emitted link.
+func extraSalamanderKeys(settings map[string]any) []string {
+	var extra []string
+	for k := range settings {
+		if k != "password" {
+			extra = append(extra, k)
+		}
+	}
+	sort.Strings(extra)
+	return extra
+}