Add an experimental HTTP based peer discovery engine that uses signed gzipped protocol buffers.

core/src/main/java/org/bitcoinj/net/discovery/HttpDiscovery.java

@@ -0,0 +1,94 @@
+/**
+ * Copyright 2014 Mike Hearn
+ *
+ * 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 org.bitcoinj.net.discovery;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.protobuf.InvalidProtocolBufferException;
+import org.bitcoin.crawler.PeerSeedProtos;
+import org.bitcoinj.core.*;
+
+import javax.annotation.Nullable;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.InetSocketAddress;
+import java.net.URI;
+import java.security.SignatureException;
+import java.util.Arrays;
+import java.util.concurrent.TimeUnit;
+import java.util.zip.GZIPInputStream;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+/**
+ * A class that knows how to read signed sets of seeds over HTTP, using a simple protobuf based protocol. See the
+ * peerseeds.proto file for the definition, with a gzipped delimited SignedPeerSeeds being the root of the data.
+ * This is not currently in use by the Bitcoin community, but rather, is here for experimentation.
+ */
+public class HttpDiscovery implements PeerDiscovery {
+    private final ECKey pubkey;
+    private final URI uri;
+    private final NetworkParameters params;
+
+    /**
+     * Constructs a discovery object that will read data from the given HTTP[S] URI and, if a public key is provided,
+     * will check the signature using that key.
+     */
+    public HttpDiscovery(NetworkParameters params, URI uri, @Nullable ECKey pubkey) {
+        checkArgument(uri.getScheme().startsWith("http"));
+        this.uri = uri;
+        this.pubkey = pubkey;
+        this.params = params;
+    }
+
+    @Override
+    public InetSocketAddress[] getPeers(long timeoutValue, TimeUnit timeoutUnit) throws PeerDiscoveryException {
+        try {
+            HttpURLConnection conn = (HttpURLConnection) uri.toURL().openConnection();
+            conn.setRequestProperty("User-Agent", "bitcoinj " + VersionMessage.BITCOINJ_VERSION);
+            InputStream stream = conn.getInputStream();
+            GZIPInputStream zip = new GZIPInputStream(stream);
+            PeerSeedProtos.SignedPeerSeeds proto = PeerSeedProtos.SignedPeerSeeds.parseDelimitedFrom(zip);
+            stream.close();
+            return protoToAddrs(proto);
+        } catch (Exception e) {
+            throw new PeerDiscoveryException(e);
+        }
+    }
+
+    @VisibleForTesting
+    public InetSocketAddress[] protoToAddrs(PeerSeedProtos.SignedPeerSeeds proto) throws PeerDiscoveryException, InvalidProtocolBufferException, SignatureException {
+        if (pubkey != null) {
+            if (!Arrays.equals(proto.getPubkey().toByteArray(), pubkey.getPubKey()))
+                throw new PeerDiscoveryException("Public key mismatch");
+            Sha256Hash hash = Sha256Hash.create(proto.getPeerSeeds().toByteArray());
+            pubkey.verifyOrThrow(hash.getBytes(), proto.getSignature().toByteArray());
+        }
+        PeerSeedProtos.PeerSeeds seeds = PeerSeedProtos.PeerSeeds.parseFrom(proto.getPeerSeeds());
+        if (seeds.getTimestamp() < Utils.currentTimeSeconds() - (60 * 60 * 24))
+            throw new PeerDiscoveryException("Seed data is more than one day old: replay attack?");
+        if (!seeds.getNet().equals(params.getPaymentProtocolId()))
+            throw new PeerDiscoveryException("Network mismatch");
+        InetSocketAddress[] results = new InetSocketAddress[seeds.getSeedCount()];
+        int i = 0;
+        for (PeerSeedProtos.PeerSeedData data : seeds.getSeedList())
+            results[i++] = new InetSocketAddress(data.getIpAddress(), data.getPort());
+        return results;
+    }
+
+    @Override
+    public void shutdown() {
+    }
+}

core/src/peerseeds.proto

@@ -0,0 +1,26 @@
+package org.bitcoin.crawler;
+
+//
+// A simple protocol for describing signed sets of IP addresses. Intended to be distributed via HTTP[S] or in files.
+//
+
+option java_package = "org.bitcoin.crawler";
+option java_outer_classname = "PeerSeedProtos";
+
+message PeerSeedData {
+    required string ip_address = 1;
+    required uint32 port = 2;
+    required uint32 services = 3;
+}
+
+message PeerSeeds {
+    repeated PeerSeedData seed = 1;
+    required uint64 timestamp = 2;   // seconds since UNIX epoch
+    required string net = 3;
+}
+
+message SignedPeerSeeds {
+    required bytes peer_seeds = 1;
+    required bytes signature = 2;
+    required bytes pubkey = 3;
+}

wallettemplate/src/main/java/wallettemplate/Main.java

@@ -2,7 +2,6 @@ package wallettemplate;
 
 import org.bitcoinj.core.NetworkParameters;
 import org.bitcoinj.kits.WalletAppKit;
-import org.bitcoinj.params.MainNetParams;
 import org.bitcoinj.params.RegTestParams;
 import org.bitcoinj.params.TestNet3Params;
 import org.bitcoinj.utils.BriefLogFormatter;
@@ -120,6 +119,7 @@ public class Main extends Application {
         } else if (params == TestNet3Params.get()) {
             // As an example!
             bitcoin.useTor();
+            // bitcoin.setDiscovery(new HttpDiscovery(params, URI.create("http://localhost:8080/peers"), ECKey.fromPublicOnly(BaseEncoding.base16().decode("02cba68cfd0679d10b186288b75a59f9132b1b3e222f6332717cb8c4eb2040f940".toUpperCase()))));
         }
         bitcoin.setDownloadListener(controller.progressBarUpdater())
                .setBlockingStartup(false)