/**
* Copyright 2011 Micheal Swiggs
* <p>
* 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
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* 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 io.bitsquare.btc;
import com.runjva.sourceforge.jsocks.protocol.Socks5Proxy;
import com.runjva.sourceforge.jsocks.protocol.SocksSocket;
import org.bitcoinj.core.NetworkParameters;
import org.bitcoinj.net.discovery.PeerDiscovery;
import org.bitcoinj.net.discovery.PeerDiscoveryException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.annotation.Nullable;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.concurrent.TimeUnit;
/**
* SeedPeersSocks5Dns resolves peers via Proxy (Socks5) remote DNS.
*/
public class SeedPeersSocks5Dns implements PeerDiscovery {
private Socks5Proxy proxy;
private NetworkParameters params;
private InetSocketAddress[] seedAddrs;
private InetSocketAddress[] seedAddrsIP;
private int pnseedIndex;
private final InetSocketAddress[] seedAddrsResolved;
private static final Logger log = LoggerFactory.getLogger(SeedPeersSocks5Dns.class);
/**
* Supports finding peers by hostname over a socks5 proxy.
*
* @param Socks5Proxy proxy the socks5 proxy to connect over.
* @param NetworkParameters param to be used for seed and port information.
*/
public SeedPeersSocks5Dns(Socks5Proxy proxy, NetworkParameters params) {
this.proxy = proxy;
this.params = params;
this.seedAddrs = convertAddrsString(params.getDnsSeeds(), params.getPort());
if (false) {
// This is an example of how .onion servers could be used. Unfortunately there is presently no way
// to hand the onion address (or a connected socket) back to bitcoinj without it crashing in PeerAddress.
// note: the onion addresses should be added into bitcoinj NetworkParameters classes, eg for mainnet, testnet
// not here!
this.seedAddrs = new InetSocketAddress[]{InetSocketAddress.createUnresolved("cajrifqkvalh2ooa.onion", 8333),
InetSocketAddress.createUnresolved("bk7yp6epnmcllq72.onion", 8333)
};
}
seedAddrsResolved = new InetSocketAddress[seedAddrs.length];
for (int idx = seedAddrs.length; idx < seedAddrsResolved.length; idx++) {
seedAddrsResolved[idx] = seedAddrsIP[idx - seedAddrs.length];
}
}
/**
* Acts as an iterator, returning the address of each node in the list sequentially.
* Once all the list has been iterated, null will be returned for each subsequent query.
*
* @return InetSocketAddress - The address/port of the next node.
* @throws PeerDiscoveryException
*/
@Nullable
public InetSocketAddress getPeer() throws PeerDiscoveryException {
try {
return nextPeer();
} catch (UnknownHostException e) {
throw new PeerDiscoveryException(e);
}
}
/**
* worker for getPeer()
*/
@Nullable
private InetSocketAddress nextPeer() throws UnknownHostException, PeerDiscoveryException {
if (seedAddrs == null || seedAddrs.length == 0) {
throw new PeerDiscoveryException("No IP address seeds configured; unable to find any peers");
}
if (pnseedIndex >= seedAddrsResolved.length) {
return null;
}
if (seedAddrsResolved[pnseedIndex] == null) {
seedAddrsResolved[pnseedIndex] = lookup(proxy, seedAddrs[pnseedIndex]);
}
log.error("SeedPeersSocks5Dns::nextPeer: " + seedAddrsResolved[pnseedIndex]);
return seedAddrsResolved[pnseedIndex++];
}
/**
* Returns an array containing all the Bitcoin nodes within the list.
*/
@Override
public InetSocketAddress[] getPeers(long timeoutValue, TimeUnit timeoutUnit) throws PeerDiscoveryException {
try {
return allPeers();
} catch (UnknownHostException e) {
throw new PeerDiscoveryException(e);
}
}
/**
* returns all seed peers, performs hostname lookups if necessary.
*/
private InetSocketAddress[] allPeers() throws UnknownHostException {
for (int i = 0; i < seedAddrsResolved.length; ++i) {
if (seedAddrsResolved[i] == null) {
seedAddrsResolved[i] = lookup(proxy, seedAddrs[i]);
}
}
return seedAddrsResolved;
}
/**
* Resolves a hostname via remote DNS over socks5 proxy.
*/
@Nullable
public static InetSocketAddress lookup(Socks5Proxy proxy, InetSocketAddress addr) {
if (!addr.isUnresolved()) {
return addr;
}
try {
SocksSocket proxySocket = new SocksSocket(proxy, addr.getHostString(), addr.getPort());
InetAddress addrResolved = proxySocket.getInetAddress();
proxySocket.close();
if (addrResolved != null) {
log.debug("Resolved " + addr.getHostString() + " to " + addrResolved.getHostAddress());
return new InetSocketAddress(addrResolved, addr.getPort());
} else {
// note: .onion nodes fall in here when proxy is Tor. But they have no IP address.
// Unfortunately bitcoinj crashes in PeerAddress if it finds an unresolved address.
log.error("Connected to " + addr.getHostString() + ". But did not resolve to address.");
}
} catch (Exception e) {
log.warn("Error resolving " + addr.getHostString() + ". Exception:\n" + e.toString());
}
return null;
}
/**
* Converts an array of hostnames to array of unresolved InetSocketAddress
*/
private InetSocketAddress[] convertAddrsString(String[] addrs, int port) {
InetSocketAddress[] list = new InetSocketAddress[addrs.length];
for (int i = 0; i < addrs.length; i++) {
list[i] = InetSocketAddress.createUnresolved(addrs[i], port);
}
return list;
}
@Override
public void shutdown() {
}
}