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

4 files changed, 8 insertions, 9 deletions

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 @@ package android.net.netlink;
 
 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 @@ public class NetlinkMessage {
         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 @@ public class RtNetlinkNeighborMessage extends NetlinkMessage {
         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 @@ public class RtNetlinkNeighborMessage extends NetlinkMessage {
             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 class StructNlMsgErr {
     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