[mdns] allow hostnames beginning with a digit
A Matter device uses a hex as the hostname so it may begin with a digit
which wasn't allowed in NsdService. This CL looses this check to allow
Matter devices to register their services at Android Thread Border
Router.
Bug: 334828525
Test: CI
Change-Id: Ia779791e214158a08c2ec06adf8d5630ec8ea616
diff --git a/service-t/src/com/android/server/NsdService.java b/service-t/src/com/android/server/NsdService.java
index 8552eec..7d077d5 100644
--- a/service-t/src/com/android/server/NsdService.java
+++ b/service-t/src/com/android/server/NsdService.java
@@ -1825,12 +1825,20 @@
* <p>For now NsdService only allows single-label hostnames conforming to RFC 1035. In other
* words, the hostname should be at most 63 characters long and it only contains letters, digits
* and hyphens.
+ *
+ * <p>Additionally, this allows hostname starting with a digit to support Matter devices. Per
+ * Matter spec 4.3.1.1:
+ *
+ * <p>The target host name SHALL be constructed using one of the available link-layer addresses,
+ * such as a 48-bit device MAC address (for Ethernet and Wi‑Fi) or a 64-bit MAC Extended Address
+ * (for Thread) expressed as a fixed-length twelve-character (or sixteen-character) hexadecimal
+ * string, encoded as ASCII (UTF-8) text using capital letters, e.g., B75AFB458ECD.<domain>.
*/
public static boolean checkHostname(@Nullable String hostname) {
if (hostname == null) {
return true;
}
- String HOSTNAME_REGEX = "^[a-zA-Z]([a-zA-Z0-9-_]{0,61}[a-zA-Z0-9])?$";
+ String HOSTNAME_REGEX = "^[a-zA-Z0-9]([a-zA-Z0-9-_]{0,61}[a-zA-Z0-9])?$";
return Pattern.compile(HOSTNAME_REGEX).matcher(hostname).matches();
}
diff --git a/tests/unit/java/com/android/server/NsdServiceTest.java b/tests/unit/java/com/android/server/NsdServiceTest.java
index d91e29c..78b9575 100644
--- a/tests/unit/java/com/android/server/NsdServiceTest.java
+++ b/tests/unit/java/com/android/server/NsdServiceTest.java
@@ -41,6 +41,7 @@
import static com.android.server.NsdService.DEFAULT_RUNNING_APP_ACTIVE_IMPORTANCE_CUTOFF;
import static com.android.server.NsdService.MdnsListener;
import static com.android.server.NsdService.NO_TRANSACTION;
+import static com.android.server.NsdService.checkHostname;
import static com.android.server.NsdService.parseTypeAndSubtype;
import static com.android.testutils.ContextUtils.mockService;
@@ -53,6 +54,7 @@
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertThrows;
import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.ArgumentMatchers.argThat;
@@ -1723,6 +1725,36 @@
}
@Test
+ public void TestCheckHostname() {
+ // Valid cases
+ assertTrue(checkHostname(null));
+ assertTrue(checkHostname("a"));
+ assertTrue(checkHostname("1"));
+ assertTrue(checkHostname("a-1234-bbbb-cccc000"));
+ assertTrue(checkHostname("A-1234-BBbb-CCCC000"));
+ assertTrue(checkHostname("1234-bbbb-cccc000"));
+ assertTrue(checkHostname("0123456789abcdef"
+ + "0123456789abcdef"
+ + "0123456789abcdef"
+ + "0123456789abcde" // 63 characters
+ ));
+
+ // Invalid cases
+ assertFalse(checkHostname("?"));
+ assertFalse(checkHostname("/"));
+ assertFalse(checkHostname("a-"));
+ assertFalse(checkHostname("B-"));
+ assertFalse(checkHostname("-A"));
+ assertFalse(checkHostname("-b"));
+ assertFalse(checkHostname("-1-"));
+ assertFalse(checkHostname("0123456789abcdef"
+ + "0123456789abcdef"
+ + "0123456789abcdef"
+ + "0123456789abcdef" // 64 characters
+ ));
+ }
+
+ @Test
@EnableCompatChanges(ENABLE_PLATFORM_MDNS_BACKEND)
public void testEnablePlatformMdnsBackend() {
final NsdManager client = connectClient(mService);