Refactor the IpPrefix API and implementation:

 * Now IpPrefix uses IpAddress to represent the subnet address
 * The IpPrefix subnet address is masked-out by the prefix length.
   E.g., IpPrefix("1.2.3.4/24") is now stored as IpPrefix("1.2.3.0/24")
 * Removed IpPrefix methods that are not used or don't apply anymore
 * Replaced usage of IpPrefix with IpAddress where appropriate

@@ -36,7 +36,6 @@ import org.onlab.onos.net.host.InterfaceIpAddress;
 import org.onlab.onos.net.host.PortAddresses;
 import org.onlab.packet.IpAddress;
 import org.onlab.packet.IpPrefix;
-import org.onlab.packet.Ip4Prefix;
 import org.onlab.packet.MacAddress;
 import org.slf4j.Logger;
 
@@ -81,12 +80,8 @@ public class NetworkConfigReader {
                         if (splits.length != 2) {
                             throw new IllegalArgumentException("Invalid IP address and prefix length format");
                         }
-                        //
-                        // TODO: For now we need Ip4Prefix to mask-out the
-                        // subnet address.
-                        //
-                        Ip4Prefix subnet4 = new Ip4Prefix(strIp);
-                        IpPrefix subnet = IpPrefix.valueOf(subnet4.toString());
+                        // NOTE: IpPrefix will mask-out the bits after the prefix length.
+                        IpPrefix subnet = IpPrefix.valueOf(strIp);
                         IpAddress addr = IpAddress.valueOf(splits[0]);
                         InterfaceIpAddress ia =
                             new InterfaceIpAddress(addr, subnet);

@@ -73,7 +73,7 @@ public class RouteEntry {
         }
 
         StringBuilder result = new StringBuilder(ip4Prefix.prefixLength());
-        long value = ip4Prefix.toInt();
+        long value = ip4Prefix.address().toInt() & 0xffffffffL;
         for (int i = 0; i < ip4Prefix.prefixLength(); i++) {
             long mask = 1 << (IpPrefix.MAX_INET_MASK_LENGTH - 1 - i);
             result.append(((value & mask) == 0) ? "0" : "1");

@@ -188,7 +188,7 @@ class TestBgpPeerChannelHandler extends SimpleChannelHandler {
             int prefixBytelen = (prefixBitlen + 7) / 8;         // Round-up
             message.writeByte(prefixBitlen);
 
-            IpAddress address = prefix.toIpAddress();
+            IpAddress address = prefix.address();
             long value = address.toInt() & 0xffffffffL;
             for (int i = 0; i < IpAddress.INET_BYTE_LENGTH; i++) {
                 if (prefixBytelen-- == 0) {

@@ -22,7 +22,7 @@ import java.util.Objects;
 import org.onlab.onos.net.PortNumber;
 import org.onlab.onos.net.flow.instructions.Instruction;
 import org.onlab.onos.net.flow.instructions.Instructions;
-import org.onlab.packet.IpPrefix;
+import org.onlab.packet.IpAddress;
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
 
@@ -181,12 +181,12 @@ public final class DefaultTrafficTreatment implements TrafficTreatment {
         }
 
         @Override
-        public Builder setIpSrc(IpPrefix addr) {
+        public Builder setIpSrc(IpAddress addr) {
             return add(Instructions.modL3Src(addr));
         }
 
         @Override
-        public Builder setIpDst(IpPrefix addr) {
+        public Builder setIpDst(IpAddress addr) {
             return add(Instructions.modL3Dst(addr));
         }
 

@@ -19,7 +19,7 @@ import java.util.List;
 
 import org.onlab.onos.net.PortNumber;
 import org.onlab.onos.net.flow.instructions.Instruction;
-import org.onlab.packet.IpPrefix;
+import org.onlab.packet.IpAddress;
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
 
@@ -92,14 +92,14 @@ public interface TrafficTreatment {
          * @param addr an ip
          * @return a treatment builder
          */
-        public Builder setIpSrc(IpPrefix addr);
+        public Builder setIpSrc(IpAddress addr);
 
         /**
          * Sets the dst l3 address.
          * @param addr an ip
          * @return a treatment builder
          */
-        public Builder setIpDst(IpPrefix addr);
+        public Builder setIpDst(IpAddress addr);
 
         /**
          * Sets the optical channel ID or lambda.

@@ -27,7 +27,7 @@ import org.onlab.onos.net.flow.instructions.L2ModificationInstruction.L2SubType;
 import org.onlab.onos.net.flow.instructions.L2ModificationInstruction.ModEtherInstruction;
 import org.onlab.onos.net.flow.instructions.L3ModificationInstruction.L3SubType;
 import org.onlab.onos.net.flow.instructions.L3ModificationInstruction.ModIPInstruction;
-import org.onlab.packet.IpPrefix;
+import org.onlab.packet.IpAddress;
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
 
@@ -115,7 +115,7 @@ public final class Instructions {
      * @param addr the ip address to modify to.
      * @return a L3 modification
      */
-    public static L3ModificationInstruction modL3Src(IpPrefix addr) {
+    public static L3ModificationInstruction modL3Src(IpAddress addr) {
         checkNotNull(addr, "Src l3 address cannot be null");
         return new ModIPInstruction(L3SubType.IP_SRC, addr);
     }
@@ -125,7 +125,7 @@ public final class Instructions {
      * @param addr the ip address to modify to.
      * @return a L3 modification
      */
-    public static L3ModificationInstruction modL3Dst(IpPrefix addr) {
+    public static L3ModificationInstruction modL3Dst(IpAddress addr) {
         checkNotNull(addr, "Dst l3 address cannot be null");
         return new ModIPInstruction(L3SubType.IP_DST, addr);
     }

@@ -19,7 +19,7 @@ import static com.google.common.base.MoreObjects.toStringHelper;
 
 import java.util.Objects;
 
-import org.onlab.packet.IpPrefix;
+import org.onlab.packet.IpAddress;
 
 /**
  * Abstraction of a single traffic treatment step.
@@ -60,9 +60,9 @@ public abstract class L3ModificationInstruction implements Instruction {
     public static final class ModIPInstruction extends L3ModificationInstruction {
 
         private final L3SubType subtype;
-        private final IpPrefix ip;
+        private final IpAddress ip;
 
-        public ModIPInstruction(L3SubType subType, IpPrefix addr) {
+        public ModIPInstruction(L3SubType subType, IpAddress addr) {
 
             this.subtype = subType;
             this.ip = addr;
@@ -73,7 +73,7 @@ public abstract class L3ModificationInstruction implements Instruction {
             return this.subtype;
         }
 
-        public IpPrefix ip() {
+        public IpAddress ip() {
             return this.ip;
         }
 

@@ -38,7 +38,7 @@ public final class IpPrefixSerializer extends Serializer<IpPrefix> {
     @Override
     public void write(Kryo kryo, Output output,
             IpPrefix object) {
-        byte[] octs = object.toOctets();
+        byte[] octs = object.address().toOctets();
         output.writeInt(octs.length);
         output.writeBytes(octs);
         output.writeInt(object.prefixLength());

@@ -31,6 +31,7 @@ import org.onlab.onos.net.flow.FlowRule;
 import org.onlab.onos.net.flow.TrafficSelector;
 import org.onlab.onos.net.flow.TrafficTreatment;
 import org.onlab.onos.openflow.controller.Dpid;
+import org.onlab.packet.IpAddress;
 import org.onlab.packet.IpPrefix;
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
@@ -167,24 +168,12 @@ public class FlowEntryBuilder {
             case SET_NW_DST:
                 OFActionSetNwDst nwdst = (OFActionSetNwDst) act;
                 IPv4Address di = nwdst.getNwAddr();
-                if (di.isCidrMask()) {
-                    builder.setIpDst(IpPrefix.valueOf(di.getInt(),
-                            di.asCidrMaskLength()));
-                } else {
-                    builder.setIpDst(IpPrefix.valueOf(di.getInt(),
-                                        IpPrefix.MAX_INET_MASK_LENGTH));
-                }
+                builder.setIpDst(IpAddress.valueOf(di.getInt()));
                 break;
             case SET_NW_SRC:
                 OFActionSetNwSrc nwsrc = (OFActionSetNwSrc) act;
                 IPv4Address si = nwsrc.getNwAddr();
-                if (si.isCidrMask()) {
-                    builder.setIpSrc(IpPrefix.valueOf(si.getInt(),
-                            si.asCidrMaskLength()));
-                } else {
-                    builder.setIpSrc(IpPrefix.valueOf(si.getInt(),
-                                        IpPrefix.MAX_INET_MASK_LENGTH));
-                }
+                builder.setIpSrc(IpAddress.valueOf(si.getInt()));
                 break;
             case EXPERIMENTER:
                 OFActionExperimenter exp = (OFActionExperimenter) act;

@@ -29,6 +29,8 @@ import org.onlab.onos.net.flow.criteria.Criteria.TcpPortCriterion;
 import org.onlab.onos.net.flow.criteria.Criteria.VlanIdCriterion;
 import org.onlab.onos.net.flow.criteria.Criteria.VlanPcpCriterion;
 import org.onlab.onos.net.flow.criteria.Criterion;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.IpPrefix;
 import org.projectfloodlight.openflow.protocol.OFFactory;
 import org.projectfloodlight.openflow.protocol.OFFlowAdd;
 import org.projectfloodlight.openflow.protocol.OFFlowDelete;
@@ -141,22 +143,30 @@ public abstract class FlowModBuilder {
                 break;
             case IPV4_DST:
                 ip = (IPCriterion) c;
-                if (ip.ip().isMasked()) {
-                    Masked<IPv4Address> maskedIp = Masked.of(IPv4Address.of(ip.ip().toInt()),
-                            IPv4Address.of(ip.ip().netmask().toInt()));
+                if (ip.ip().prefixLength() != IpPrefix.MAX_INET_MASK_LENGTH) {
+                    IpAddress maskAddr =
+                        IpAddress.makeMaskPrefix(ip.ip().prefixLength());
+                    Masked<IPv4Address> maskedIp =
+                        Masked.of(IPv4Address.of(ip.ip().address().toInt()),
+                                  IPv4Address.of(maskAddr.toInt()));
                     mBuilder.setMasked(MatchField.IPV4_DST, maskedIp);
                 } else {
-                    mBuilder.setExact(MatchField.IPV4_DST, IPv4Address.of(ip.ip().toInt()));
+                    mBuilder.setExact(MatchField.IPV4_DST,
+                                IPv4Address.of(ip.ip().address().toInt()));
                 }
                 break;
             case IPV4_SRC:
                 ip = (IPCriterion) c;
-                if (ip.ip().isMasked()) {
-                    Masked<IPv4Address> maskedIp = Masked.of(IPv4Address.of(ip.ip().toInt()),
-                            IPv4Address.of(ip.ip().netmask().toInt()));
+                if (ip.ip().prefixLength() != IpPrefix.MAX_INET_MASK_LENGTH) {
+                    IpAddress maskAddr =
+                        IpAddress.makeMaskPrefix(ip.ip().prefixLength());
+                    Masked<IPv4Address> maskedIp =
+                        Masked.of(IPv4Address.of(ip.ip().address().toInt()),
+                                  IPv4Address.of(maskAddr.toInt()));
                     mBuilder.setMasked(MatchField.IPV4_SRC, maskedIp);
                 } else {
-                    mBuilder.setExact(MatchField.IPV4_SRC, IPv4Address.of(ip.ip().toInt()));
+                    mBuilder.setExact(MatchField.IPV4_SRC,
+                                IPv4Address.of(ip.ip().address().toInt()));
                 }
                 break;
             case IP_PROTO:

@@ -21,7 +21,8 @@ import java.util.Objects;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
- * A class representing an IPv4 address.
+ * A class representing an IP address.
+ * TODO: Add support for IPv6 as well.
  */
 public final class IpAddress implements Comparable<IpAddress> {
     // IP Versions
@@ -44,8 +45,6 @@ public final class IpAddress implements Comparable<IpAddress> {
      * @param value the IP address value
      */
     private IpAddress(Version version, byte[] value) {
-        checkNotNull(value);
-
         this.version = version;
         this.octets = Arrays.copyOf(value, INET_BYTE_LENGTH);
     }
@@ -53,7 +52,7 @@ public final class IpAddress implements Comparable<IpAddress> {
     /**
      * Converts an integer into an IPv4 address.
      *
-     * @param value an integer representing an IPv4 value
+     * @param value an integer representing an IPv4 address value
      * @return an IP address
      */
     public static IpAddress valueOf(int value) {
@@ -70,6 +69,7 @@ public final class IpAddress implements Comparable<IpAddress> {
      * @return an IP address
      */
     public static IpAddress valueOf(byte[] value) {
+        checkNotNull(value);
         return new IpAddress(Version.INET, value);
     }
 
@@ -106,13 +106,13 @@ public final class IpAddress implements Comparable<IpAddress> {
     /**
      * Converts a dotted-decimal string (x.x.x.x) into an IPv4 address.
      *
-     * @param address a IP address in string form, e.g. "10.0.0.1".
+     * @param address an IP address in string form, e.g. "10.0.0.1"
      * @return an IP address
      */
     public static IpAddress valueOf(String address) {
         final String[] net = address.split("\\.");
         if (net.length != INET_BYTE_LENGTH) {
-            String msg = "Malformed IPv4 address string; " +
+            String msg = "Malformed IPv4 address string: " + address + "." +
                 "Address must have four decimal values separated by dots (.)";
             throw new IllegalArgumentException(msg);
         }
@@ -154,20 +154,21 @@ public final class IpAddress implements Comparable<IpAddress> {
     /**
      * Creates an IP network mask prefix.
      *
-     * @param prefixLen the length of the mask prefix. Must be in the interval
-     * [0, 32] for IPv4
+     * @param prefixLength the length of the mask prefix. Must be in the
+     * interval [0, 32] for IPv4
      * @return a new IP address that contains a mask prefix of the
      * specified length
      */
-    public static IpAddress makeMaskPrefix(int prefixLen) {
+    public static IpAddress makeMaskPrefix(int prefixLength) {
         // Verify the prefix length
-        if ((prefixLen < 0) || (prefixLen > INET_BIT_LENGTH)) {
-            final String msg = "Invalid IPv4 prefix length: " + prefixLen +
+        if ((prefixLength < 0) || (prefixLength > INET_BIT_LENGTH)) {
+            final String msg = "Invalid IPv4 prefix length: " + prefixLength +
                 ". Must be in the interval [0, 32].";
             throw new IllegalArgumentException(msg);
         }
 
-        long v = (0xffffffffL << (INET_BIT_LENGTH - prefixLen)) & 0xffffffffL;
+        long v =
+            (0xffffffffL << (INET_BIT_LENGTH - prefixLength)) & 0xffffffffL;
         return IpAddress.valueOf((int) v);
     }
 
@@ -176,14 +177,14 @@ public final class IpAddress implements Comparable<IpAddress> {
      * mask length.
      *
      * @param addr the address to mask
-     * @param prefixLen the length of the mask prefix. Must be in the interval
-     * [0, 32] for IPv4
+     * @param prefixLength the length of the mask prefix. Must be in the
+     * interval [0, 32] for IPv4
      * @return a new IP address that is masked with a mask prefix of the
      * specified length
      */
     public static IpAddress makeMaskedAddress(final IpAddress addr,
-                                              int prefixLen) {
-        IpAddress mask = IpAddress.makeMaskPrefix(prefixLen);
+                                              int prefixLength) {
+        IpAddress mask = IpAddress.makeMaskPrefix(prefixLength);
         byte[] net = new byte[INET_BYTE_LENGTH];
 
         // Mask each byte
@@ -207,7 +208,7 @@ public final class IpAddress implements Comparable<IpAddress> {
 
     @Override
     public boolean equals(Object obj) {
-        if (obj == this) {
+        if (this == obj) {
             return true;
         }
         if ((obj == null) || (getClass() != obj.getClass())) {
@@ -221,7 +222,7 @@ public final class IpAddress implements Comparable<IpAddress> {
     @Override
     /*
      * (non-Javadoc)
-     * format is "x.x.x.x" for IPv4 addresses.
+     * The format is "x.x.x.x" for IPv4 addresses.
      *
      * @see java.lang.Object#toString()
      */

@@ -22,7 +22,7 @@ import static org.junit.Assert.assertTrue;
 import java.util.Arrays;
 
 import org.junit.Test;
-import org.onlab.packet.IpPrefix.Version;
+import org.onlab.packet.IpAddress.Version;
 
 import com.google.common.testing.EqualsTester;
 
@@ -30,8 +30,9 @@ public class IpPrefixTest {
 
     private static final byte [] BYTES1 = new byte [] {0xa, 0x0, 0x0, 0xa};
     private static final byte [] BYTES2 = new byte [] {0xa, 0x0, 0x0, 0xb};
-    private static final int INTVAL1 = 167772170;
-    private static final int INTVAL2 = 167772171;
+    private static final int INTVAL0 = 0x0a000000;
+    private static final int INTVAL1 = 0x0a00000a;
+    private static final int INTVAL2 = 0x0a00000b;
     private static final String STRVAL = "10.0.0.12/16";
     private static final int MASK_LENGTH = 16;
 
@@ -59,27 +60,29 @@ public class IpPrefixTest {
     @Test
     public void basics() {
         IpPrefix ip1 = IpPrefix.valueOf(BYTES1, MASK_LENGTH);
-        final byte [] bytes = new byte [] {0xa, 0x0, 0x0, 0xa};
+        final byte [] bytes = new byte [] {0xa, 0x0, 0x0, 0x0};
 
-        //check fields
+        // check fields
         assertEquals("incorrect IP Version", Version.INET, ip1.version());
         assertEquals("incorrect netmask", 16, ip1.prefixLength());
-        assertTrue("faulty toOctets()", Arrays.equals(bytes, ip1.toOctets()));
-        assertEquals("faulty toInt()", INTVAL1, ip1.toInt());
-        assertEquals("faulty toString()", "10.0.0.10/16", ip1.toString());
+        assertTrue("faulty toOctets()",
+                   Arrays.equals(bytes, ip1.address().toOctets()));
+        assertEquals("faulty toInt()", INTVAL0, ip1.address().toInt());
+        assertEquals("faulty toString()", "10.0.0.0/16", ip1.toString());
     }
 
     @Test
     public void netmasks() {
         // masked
         IpPrefix ip1 = IpPrefix.valueOf(BYTES1, MASK_LENGTH);
-
-        IpPrefix host = IpPrefix.valueOf("0.0.0.10/16");
-        IpPrefix network = IpPrefix.valueOf("10.0.0.0/16");
-        assertEquals("incorrect host address", host, ip1.host());
-        assertEquals("incorrect network address", network, ip1.network());
-        assertEquals("incorrect netmask", "255.255.0.0", ip1.netmask().toString());
-
+        IpPrefix ip2 = IpPrefix.valueOf("10.0.0.10/16");
+        IpPrefix ip3 = IpPrefix.valueOf("10.0.0.0/16");
+        assertEquals("incorrect binary masked address",
+                     ip1.toString(), "10.0.0.0/16");
+        assertEquals("incorrect string masked address",
+                     ip2.toString(), "10.0.0.0/16");
+        assertEquals("incorrect network address",
+                     ip2.toString(), "10.0.0.0/16");
     }
 
     @Test