Merge "Try to set the hop limit to something suitable for 64share"

am: 666bb5cf28

Change-Id: I4d3dfd87d8f3f6d699095e0ae8be0ed021382d54

services/net/java/android/net/ip/RouterAdvertisementDaemon.java

@@ -119,13 +119,23 @@ public class RouterAdvertisementDaemon {
     private volatile UnicastResponder mUnicastResponder;
 
     public static class RaParams {
+        // Tethered traffic will have the hop limit properly decremented.
+        // Consequently, set the hoplimit greater by one than the upstream
+        // unicast hop limit.
+        //
+        // TODO: Dynamically pass down the IPV6_UNICAST_HOPS value from the
+        // upstream interface for more correct behaviour.
+        static final byte DEFAULT_HOPLIMIT = 65;
+
         public boolean hasDefaultRoute;
+        public byte hopLimit;
         public int mtu;
         public HashSet<IpPrefix> prefixes;
         public HashSet<Inet6Address> dnses;
 
         public RaParams() {
             hasDefaultRoute = false;
+            hopLimit = DEFAULT_HOPLIMIT;
             mtu = IPV6_MIN_MTU;
             prefixes = new HashSet<IpPrefix>();
             dnses = new HashSet<Inet6Address>();
@@ -133,6 +143,7 @@ public class RouterAdvertisementDaemon {
 
         public RaParams(RaParams other) {
             hasDefaultRoute = other.hasDefaultRoute;
+            hopLimit = other.hopLimit;
             mtu = other.mtu;
             prefixes = (HashSet) other.prefixes.clone();
             dnses = (HashSet) other.dnses.clone();
@@ -273,10 +284,12 @@ public class RouterAdvertisementDaemon {
         final ByteBuffer ra = ByteBuffer.wrap(mRA);
         ra.order(ByteOrder.BIG_ENDIAN);
 
+        final boolean haveRaParams = (mRaParams != null);
         boolean shouldSendRA = false;
 
         try {
-            putHeader(ra, mRaParams != null && mRaParams.hasDefaultRoute);
+            putHeader(ra, haveRaParams && mRaParams.hasDefaultRoute,
+                    haveRaParams ? mRaParams.hopLimit : RaParams.DEFAULT_HOPLIMIT);
             putSlla(ra, mInterface.macAddr.toByteArray());
             mRaLength = ra.position();
 
@@ -287,7 +300,7 @@ public class RouterAdvertisementDaemon {
             //
             // putExpandedFlagsOption(ra);
 
-            if (mRaParams != null) {
+            if (haveRaParams) {
                 putMtu(ra, mRaParams.mtu);
                 mRaLength = ra.position();
 
@@ -348,7 +361,7 @@ public class RouterAdvertisementDaemon {
     private static byte asByte(int value) { return (byte) value; }
     private static short asShort(int value) { return (short) value; }
 
-    private static void putHeader(ByteBuffer ra, boolean hasDefaultRoute) {
+    private static void putHeader(ByteBuffer ra, boolean hasDefaultRoute, byte hopLimit) {
         /**
             Router Advertisement Message Format
 
@@ -366,11 +379,10 @@ public class RouterAdvertisementDaemon {
             |   Options ...
             +-+-+-+-+-+-+-+-+-+-+-+-
         */
-        final byte DEFAULT_HOPLIMIT = 64;
         ra.put(ICMPV6_ND_ROUTER_ADVERT)
           .put(asByte(0))
           .putShort(asShort(0))
-          .put(DEFAULT_HOPLIMIT)
+          .put(hopLimit)
           // RFC 4191 "high" preference, iff. advertising a default route.
           .put(hasDefaultRoute ? asByte(0x08) : asByte(0))
           .putShort(hasDefaultRoute ? asShort(DEFAULT_LIFETIME) : asShort(0))