Preserve IPv6 wildcard binds in preconn-managed services

go-gost/x/socket/preconn_manager.go

@@ -164,7 +164,9 @@ func parseListenAddr(addr string) (string, string, error) {
 	if err != nil {
 		return "", "", err
 	}
-	if host == "" || host == "0.0.0.0" || host == "::" {
+	if host == "" || host == "0.0.0.0" {
+		// Keep the legacy empty-host behavior mapped to IPv4 wildcard, but
+		// preserve an explicit "::" so dual-stack listeners stay IPv6-capable.
 		host = "0.0.0.0"
 	}
 	return host, port, nil

go-gost/x/socket/preconn_manager_test.go

@@ -0,0 +1,52 @@
+package socket
+
+import "testing"
+
+func TestParseListenAddr(t *testing.T) {
+	tests := []struct {
+		name     string
+		addr     string
+		wantHost string
+		wantPort string
+	}{
+		{
+			name:     "defaults empty host to ipv4 wildcard",
+			addr:     ":32000",
+			wantHost: "0.0.0.0",
+			wantPort: "32000",
+		},
+		{
+			name:     "keeps ipv4 wildcard",
+			addr:     "0.0.0.0:32001",
+			wantHost: "0.0.0.0",
+			wantPort: "32001",
+		},
+		{
+			name:     "keeps ipv6 wildcard",
+			addr:     "[::]:32002",
+			wantHost: "::",
+			wantPort: "32002",
+		},
+		{
+			name:     "keeps specific ipv6 address",
+			addr:     "[2001:db8::1]:32003",
+			wantHost: "2001:db8::1",
+			wantPort: "32003",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotHost, gotPort, err := parseListenAddr(tt.addr)
+			if err != nil {
+				t.Fatalf("parseListenAddr returned error: %v", err)
+			}
+			if gotHost != tt.wantHost {
+				t.Fatalf("expected host %q, got %q", tt.wantHost, gotHost)
+			}
+			if gotPort != tt.wantPort {
+				t.Fatalf("expected port %q, got %q", tt.wantPort, gotPort)
+			}
+		})
+	}
+}