Add support to dump all multicast routes in NetlinkUtils
Test: atest NetworkStaticLibTests:com.android.net.moduletests.util.netlink.NetlinkUtilsTest
Change-Id: I07e7aa8ce677dafb94891c8075f8822dadcfd6d1
diff --git a/staticlibs/device/com/android/net/module/util/netlink/NetlinkUtils.java b/staticlibs/device/com/android/net/module/util/netlink/NetlinkUtils.java
index f6282fd..fafa5ee 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/NetlinkUtils.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/NetlinkUtils.java
@@ -31,6 +31,7 @@
import static android.system.OsConstants.SO_SNDTIMEO;
import static com.android.net.module.util.netlink.NetlinkConstants.hexify;
import static com.android.net.module.util.netlink.NetlinkConstants.NLMSG_DONE;
+import static com.android.net.module.util.netlink.NetlinkConstants.RTNL_FAMILY_IP6MR;
import static com.android.net.module.util.netlink.StructNlMsgHdr.NLM_F_DUMP;
import static com.android.net.module.util.netlink.StructNlMsgHdr.NLM_F_REQUEST;
@@ -387,6 +388,65 @@
}
}
+ /**
+ * Construct a RTM_GETROUTE message for dumping multicast IPv6 routes from kernel.
+ */
+ private static byte[] newIpv6MulticastRouteDumpRequest() {
+ final StructNlMsgHdr nlmsghdr = new StructNlMsgHdr();
+ nlmsghdr.nlmsg_type = NetlinkConstants.RTM_GETROUTE;
+ nlmsghdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+ final short shortZero = 0;
+
+ // family must be RTNL_FAMILY_IP6MR to dump IPv6 multicast routes.
+ // dstLen, srcLen, tos and scope must be zero in FIB dump request.
+ // protocol, flags must be 0, and type must be RTN_MULTICAST (if not 0) for multicast
+ // dump request.
+ // table or RTA_TABLE attributes can be used to dump a specific routing table.
+ // RTA_OIF attribute can be used to dump only routes containing given oif.
+ // Here no attributes are set so the kernel can return all multicast routes.
+ final StructRtMsg rtMsg =
+ new StructRtMsg(RTNL_FAMILY_IP6MR /* family */, shortZero /* dstLen */,
+ shortZero /* srcLen */, shortZero /* tos */, shortZero /* table */,
+ shortZero /* protocol */, shortZero /* scope */, shortZero /* type */,
+ 0L /* flags */);
+ final RtNetlinkRouteMessage msg =
+ new RtNetlinkRouteMessage(nlmsghdr, rtMsg);
+
+ final int spaceRequired = StructNlMsgHdr.STRUCT_SIZE + StructRtMsg.STRUCT_SIZE;
+ nlmsghdr.nlmsg_len = spaceRequired;
+ final byte[] bytes = new byte[NetlinkConstants.alignedLengthOf(spaceRequired)];
+ final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
+ byteBuffer.order(ByteOrder.nativeOrder());
+ msg.pack(byteBuffer);
+ return bytes;
+ }
+
+ /**
+ * Get the list of IPv6 multicast route messages from kernel.
+ */
+ public static List<RtNetlinkRouteMessage> getIpv6MulticastRoutes() {
+ final byte[] dumpMsg = newIpv6MulticastRouteDumpRequest();
+ List<RtNetlinkRouteMessage> routes = new ArrayList<>();
+ Consumer<RtNetlinkRouteMessage> handleNlDumpMsg = (msg) -> {
+ if (msg.getRtmFamily() == RTNL_FAMILY_IP6MR) {
+ // Sent rtmFamily RTNL_FAMILY_IP6MR in dump request to make sure ipv6
+ // multicast routes are included in netlink reply messages, the kernel
+ // may also reply with other kind of routes, so we filter them out here.
+ routes.add(msg);
+ }
+ };
+ try {
+ NetlinkUtils.<RtNetlinkRouteMessage>getAndProcessNetlinkDumpMessages(
+ dumpMsg, NETLINK_ROUTE, RtNetlinkRouteMessage.class,
+ handleNlDumpMsg);
+ } catch (SocketException | InterruptedIOException | ErrnoException | ParseException e) {
+ Log.e(TAG, "Failed to dump multicast routes");
+ return routes;
+ }
+
+ return routes;
+ }
+
private static void closeSocketQuietly(final FileDescriptor fd) {
try {
SocketUtils.closeSocket(fd);
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/NetlinkUtilsTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/NetlinkUtilsTest.java
index 17d4e81..0958f11 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/NetlinkUtilsTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/NetlinkUtilsTest.java
@@ -21,7 +21,7 @@
import static android.system.OsConstants.AF_UNSPEC;
import static android.system.OsConstants.EACCES;
import static android.system.OsConstants.NETLINK_ROUTE;
-
+import static com.android.net.module.util.netlink.NetlinkConstants.RTNL_FAMILY_IP6MR;
import static com.android.net.module.util.netlink.NetlinkUtils.DEFAULT_RECV_BUFSIZE;
import static com.android.net.module.util.netlink.StructNlMsgHdr.NLM_F_DUMP;
import static com.android.net.module.util.netlink.StructNlMsgHdr.NLM_F_REQUEST;
@@ -191,4 +191,17 @@
return bytes;
}
+
+ @Test
+ public void testGetIpv6MulticastRoutes_doesNotThrow() {
+ var multicastRoutes = NetlinkUtils.getIpv6MulticastRoutes();
+
+ for (var route : multicastRoutes) {
+ assertNotNull(route);
+ assertEquals("Route is not IP6MR: " + route,
+ RTNL_FAMILY_IP6MR, route.getRtmFamily());
+ assertNotNull("Route doesn't contain source: " + route, route.getSource());
+ assertNotNull("Route doesn't contain destination: " + route, route.getDestination());
+ }
+ }
}