Fix PeerAddress serialization and add a test. Patch from Noa Resare. Fixes issue 29.

src/com/google/bitcoin/core/PeerAddress.java

@@ -53,7 +53,7 @@ public class PeerAddress extends Message {
             int secs = (int)(new Date().getTime() / 1000);
             uint32ToByteStreamLE(secs, stream);
         }
-        uint64ToByteStreamLE(BigInteger.ZERO, stream);  // nServices.
+        uint64ToByteStreamLE(services, stream);  // nServices.
         // Java does not provide any utility to map an IPv4 address into IPv6 space, so we have to do it by hand.
         byte[] ipBytes = addr.getAddress();
         if (ipBytes.length == 4) {
@@ -64,9 +64,9 @@ public class PeerAddress extends Message {
             ipBytes = v6addr;
         }
         stream.write(ipBytes);
-        // And write out the port.
+        // And write out the port. Unlike the rest of the protocol, address and port is in big endian byte order.
+        stream.write((byte) (0xFF & port >> 8));
         stream.write((byte) (0xFF & port));
-        stream.write((byte) (0xFF & (port >> 8)));
     }
 
     @Override

tests/com/google/bitcoin/core/PeerAddressTest.java

@@ -0,0 +1,36 @@
+/**
+ * Copyright 2011 Noa Resare
+ *
+ * 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 com.google.bitcoin.core;
+
+import com.google.bitcoin.bouncycastle.util.encoders.Hex;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class PeerAddressTest
+{
+    @Test
+    public void testPeerAddressSerialize() throws Exception
+    {
+        // copied verbatim from https://en.bitcoin.it/wiki/Protocol_specification#Network_address
+        String fromSpec = "010000000000000000000000000000000000ffff0a000001208d";
+        PeerAddress pa = new PeerAddress(NetworkParameters.prodNet(),
+                Hex.decode(fromSpec),0,0);
+        String reserialized = Utils.bytesToHexString(pa.bitcoinSerialize());
+        assertEquals(reserialized,fromSpec );
+    }
+}