Set NLM_F_ACK in our RTM_NEWNEIGH requests
With NLM_F_ACK set in RTM_NEWNEIGH requests we get some response from
the kernel, whether there was an error or not.
Additionally:
[1] add IpReachabilityMonitor#probeNeighbor() as a public
static method, since it actually depends very little on the
class internals and might be of larger use.
[2] add a unittest for parsing NetlinkErrorMessages.
Bug: 18581716
Change-Id: I5d62e7a9972c7440f0483c38c77677436d3a1a25
diff --git a/core/java/android/net/IpReachabilityMonitor.java b/core/java/android/net/IpReachabilityMonitor.java
index cb8c866..b0f2003 100644
--- a/core/java/android/net/IpReachabilityMonitor.java
+++ b/core/java/android/net/IpReachabilityMonitor.java
@@ -76,6 +76,60 @@
private final NetlinkSocketObserver mNetlinkSocketObserver;
private final Thread mObserverThread;
+ /**
+ * Make the kernel to perform neighbor reachability detection (IPv4 ARP or IPv6 ND)
+ * for the given IP address on the specified interface index.
+ *
+ * @return true, if the request was successfully passed to the kernel; false otherwise.
+ */
+ public static boolean probeNeighbor(int ifIndex, InetAddress ip) {
+ final long IO_TIMEOUT = 300L;
+ // This currently does not cause neighbor probing if the target |ip|
+ // has been confirmed reachable within the past "delay_probe_time"
+ // seconds, i.e. within the past 5 seconds.
+ //
+ // TODO: replace with a transition directly to NUD_PROBE state once
+ // kernels are updated to do so correctly.
+ if (DBG) { Log.d(TAG, "Probing ip=" + ip.getHostAddress()); }
+
+ final byte[] msg = RtNetlinkNeighborMessage.newNewNeighborMessage(
+ 1, ip, StructNdMsg.NUD_DELAY, ifIndex, null);
+ NetlinkSocket nlSocket = null;
+ boolean returnValue = false;
+
+ try {
+ nlSocket = new NetlinkSocket(OsConstants.NETLINK_ROUTE);
+ nlSocket.connectToKernel();
+ nlSocket.sendMessage(msg, 0, msg.length, IO_TIMEOUT);
+ final ByteBuffer bytes = nlSocket.recvMessage(IO_TIMEOUT);
+ final NetlinkMessage response = NetlinkMessage.parse(bytes);
+ if (response != null && response instanceof NetlinkErrorMessage &&
+ (((NetlinkErrorMessage) response).getNlMsgError() != null) &&
+ (((NetlinkErrorMessage) response).getNlMsgError().error == 0)) {
+ returnValue = true;
+ } else {
+ String errmsg;
+ if (bytes == null) {
+ errmsg = "null recvMessage";
+ } else if (response == null) {
+ bytes.position(0);
+ errmsg = "raw bytes: " + NetlinkConstants.hexify(bytes);
+ } else {
+ errmsg = response.toString();
+ }
+ Log.e(TAG, "Error probing ip=" + ip.getHostAddress() +
+ ", errmsg=" + errmsg);
+ }
+ } catch (ErrnoException | InterruptedIOException | SocketException e) {
+ Log.d(TAG, "Error probing ip=" + ip.getHostAddress(), e);
+ }
+
+ if (nlSocket != null) {
+ nlSocket.close();
+ }
+ return returnValue;
+ }
+
public IpReachabilityMonitor(String ifName, Callback callback) throws IllegalArgumentException {
mInterfaceName = ifName;
int ifIndex = -1;
@@ -216,38 +270,10 @@
ipProbeList.addAll(mIpWatchList);
}
for (InetAddress target : ipProbeList) {
- if (!stillRunning()) { break; }
- probeIp(target);
- }
- }
-
- private void probeIp(InetAddress ip) {
- // This currently does not cause neighbor probing if the target |ip|
- // has been confirmed reachable within the past "delay_probe_time"
- // seconds, i.e. within the past 5 seconds.
- //
- // TODO: replace with a transition directly to NUD_PROBE state once
- // kernels are updated to do so correctly.
- if (DBG) { Log.d(TAG, "Probing ip=" + ip.getHostAddress()); }
-
- final byte[] msg = RtNetlinkNeighborMessage.newNewNeighborMessage(
- 1, ip, StructNdMsg.NUD_DELAY, mInterfaceIndex, null);
- NetlinkSocket nlSocket = null;
-
- try {
- nlSocket = new NetlinkSocket(OsConstants.NETLINK_ROUTE);
- nlSocket.connectToKernel();
- nlSocket.sendMessage(msg, 0, msg.length, 300);
- final NetlinkMessage response = NetlinkMessage.parse(nlSocket.recvMessage(300));
- if (response != null && response instanceof NetlinkErrorMessage) {
- Log.e(TAG, "Error probing ip=" + response.toString());
+ if (!stillRunning()) {
+ break;
}
- } catch (ErrnoException | InterruptedIOException | SocketException e) {
- Log.d(TAG, "Error probing ip=" + ip.getHostAddress(), e);
- }
-
- if (nlSocket != null) {
- nlSocket.close();
+ probeNeighbor(mInterfaceIndex, target);
}
}
diff --git a/core/java/android/net/netlink/NetlinkErrorMessage.java b/core/java/android/net/netlink/NetlinkErrorMessage.java
index dbc10d6..e275574 100644
--- a/core/java/android/net/netlink/NetlinkErrorMessage.java
+++ b/core/java/android/net/netlink/NetlinkErrorMessage.java
@@ -18,7 +18,6 @@
import android.net.netlink.StructNlMsgHdr;
import android.net.netlink.NetlinkMessage;
-import android.util.Log;
import java.nio.ByteBuffer;
diff --git a/core/java/android/net/netlink/NetlinkMessage.java b/core/java/android/net/netlink/NetlinkMessage.java
index bc04a16..3bf75ca 100644
--- a/core/java/android/net/netlink/NetlinkMessage.java
+++ b/core/java/android/net/netlink/NetlinkMessage.java
@@ -60,7 +60,7 @@
switch (nlmsghdr.nlmsg_type) {
//case NetlinkConstants.NLMSG_NOOP:
case NetlinkConstants.NLMSG_ERROR:
- return (NetlinkMessage) NetlinkErrorMessage.parse(byteBuffer);
+ return (NetlinkMessage) NetlinkErrorMessage.parse(nlmsghdr, byteBuffer);
case NetlinkConstants.NLMSG_DONE:
byteBuffer.position(byteBuffer.position() + payloadLength);
return new NetlinkMessage(nlmsghdr);
diff --git a/core/java/android/net/netlink/RtNetlinkNeighborMessage.java b/core/java/android/net/netlink/RtNetlinkNeighborMessage.java
index b5f5817..02df131 100644
--- a/core/java/android/net/netlink/RtNetlinkNeighborMessage.java
+++ b/core/java/android/net/netlink/RtNetlinkNeighborMessage.java
@@ -16,6 +16,11 @@
package android.net.netlink;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_ACK;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_DUMP;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_REPLACE;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_REQUEST;
+
import android.net.netlink.StructNdaCacheInfo;
import android.net.netlink.StructNdMsg;
import android.net.netlink.StructNlAttr;
@@ -123,7 +128,7 @@
final StructNlMsgHdr nlmsghdr = new StructNlMsgHdr();
nlmsghdr.nlmsg_len = length;
nlmsghdr.nlmsg_type = NetlinkConstants.RTM_GETNEIGH;
- nlmsghdr.nlmsg_flags = StructNlMsgHdr.NLM_F_REQUEST|StructNlMsgHdr.NLM_F_DUMP;
+ nlmsghdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
nlmsghdr.nlmsg_seq = seqNo;
nlmsghdr.pack(byteBuffer);
@@ -141,7 +146,7 @@
int seqNo, InetAddress ip, short nudState, int ifIndex, byte[] llAddr) {
final StructNlMsgHdr nlmsghdr = new StructNlMsgHdr();
nlmsghdr.nlmsg_type = NetlinkConstants.RTM_NEWNEIGH;
- nlmsghdr.nlmsg_flags = StructNlMsgHdr.NLM_F_REQUEST | StructNlMsgHdr.NLM_F_REPLACE;
+ nlmsghdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_REPLACE;
nlmsghdr.nlmsg_seq = seqNo;
final RtNetlinkNeighborMessage msg = new RtNetlinkNeighborMessage(nlmsghdr);
diff --git a/core/java/android/net/netlink/StructNlMsgErr.java b/core/java/android/net/netlink/StructNlMsgErr.java
index 6b02650..f095af4 100644
--- a/core/java/android/net/netlink/StructNlMsgErr.java
+++ b/core/java/android/net/netlink/StructNlMsgErr.java
@@ -52,11 +52,6 @@
public int error;
public StructNlMsgHdr msg;
- public StructNlMsgErr() {
- error = 0;
- msg = null;
- }
-
public void pack(ByteBuffer byteBuffer) {
// The ByteOrder must have already been set by the caller. In most
// cases ByteOrder.nativeOrder() is correct, with the possible
diff --git a/core/tests/coretests/src/android/net/netlink/NetlinkErrorMessageTest.java b/core/tests/coretests/src/android/net/netlink/NetlinkErrorMessageTest.java
new file mode 100644
index 0000000..e677475
--- /dev/null
+++ b/core/tests/coretests/src/android/net/netlink/NetlinkErrorMessageTest.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.netlink;
+
+import static android.net.netlink.StructNlMsgHdr.NLM_F_REQUEST;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_ACK;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_REPLACE;
+
+import android.net.netlink.NetlinkConstants;
+import android.net.netlink.NetlinkErrorMessage;
+import android.net.netlink.NetlinkMessage;
+import android.net.netlink.StructNlMsgErr;
+import android.util.Log;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import junit.framework.TestCase;
+import libcore.util.HexEncoding;
+
+
+public class NetlinkErrorMessageTest extends TestCase {
+ private final String TAG = "NetlinkErrorMessageTest";
+
+ // Hexadecimal representation of packet capture.
+ public static final String NLM_ERROR_OK_HEX =
+ // struct nlmsghdr
+ "24000000" + // length = 36
+ "0200" + // type = 2 (NLMSG_ERROR)
+ "0000" + // flags
+ "26350000" + // seqno
+ "64100000" + // pid = userspace process
+ // error integer
+ "00000000" + // "errno" (0 == OK)
+ // struct nlmsghdr
+ "30000000" + // length (48) of original request
+ "1C00" + // type = 28 (RTM_NEWNEIGH)
+ "0501" + // flags (NLM_F_REQUEST | NLM_F_ACK | NLM_F_REPLACE)
+ "26350000" + // seqno
+ "00000000"; // pid = kernel
+ public static final byte[] NLM_ERROR_OK =
+ HexEncoding.decode(NLM_ERROR_OK_HEX.toCharArray(), false);
+
+ public void testParseNlmErrorOk() {
+ final ByteBuffer byteBuffer = ByteBuffer.wrap(NLM_ERROR_OK);
+ byteBuffer.order(ByteOrder.LITTLE_ENDIAN); // For testing.
+ final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer);
+ assertNotNull(msg);
+ assertTrue(msg instanceof NetlinkErrorMessage);
+ final NetlinkErrorMessage errorMsg = (NetlinkErrorMessage) msg;
+
+ final StructNlMsgHdr hdr = errorMsg.getHeader();
+ assertNotNull(hdr);
+ assertEquals(36, hdr.nlmsg_len);
+ assertEquals(NetlinkConstants.NLMSG_ERROR, hdr.nlmsg_type);
+ assertEquals(0, hdr.nlmsg_flags);
+ assertEquals(13606, hdr.nlmsg_seq);
+ assertEquals(4196, hdr.nlmsg_pid);
+
+ final StructNlMsgErr err = errorMsg.getNlMsgError();
+ assertNotNull(err);
+ assertEquals(0, err.error);
+ assertNotNull(err.msg);
+ assertEquals(48, err.msg.nlmsg_len);
+ assertEquals(NetlinkConstants.RTM_NEWNEIGH, err.msg.nlmsg_type);
+ assertEquals((NLM_F_REQUEST | NLM_F_ACK | NLM_F_REPLACE), err.msg.nlmsg_flags);
+ assertEquals(13606, err.msg.nlmsg_seq);
+ assertEquals(0, err.msg.nlmsg_pid);
+ }
+}
diff --git a/core/tests/coretests/src/android/net/netlink/RtNetlinkNeighborMessageTest.java b/core/tests/coretests/src/android/net/netlink/RtNetlinkNeighborMessageTest.java
index a7bebad..19ee000 100644
--- a/core/tests/coretests/src/android/net/netlink/RtNetlinkNeighborMessageTest.java
+++ b/core/tests/coretests/src/android/net/netlink/RtNetlinkNeighborMessageTest.java
@@ -222,7 +222,7 @@
// struct nlmsghdr
"30000000" + // length = 48
"1c00" + // type = 28 (RTM_NEWNEIGH)
- "0101" + // flags (NLM_F_REQUEST | NLM_F_REPLACE)
+ "0501" + // flags (NLM_F_REQUEST | NLM_F_ACK | NLM_F_REPLACE)
"4b0a0000" + // seqno
"00000000" + // pid (0 == kernel)
// struct ndmsg