--- /dev/null
+package org.ldk.batteries;
+
+import org.ldk.structs.*;
+
+import java.io.IOException;
+import java.net.SocketAddress;
+import java.net.StandardSocketOptions;
+import java.nio.ByteBuffer;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+
+public class NioPeerHandler {
+ private static class Peer {
+ SocketDescriptor descriptor;
+ // When we are told by LDK to disconnect, we can't return to LDK until we are sure
+ // won't call any more read/write PeerManager functions with the same connection.
+ // This is set to true if we're in such a condition (with disconnect checked
+ // before with the Peer monitor lock held) and false when we can return.
+ boolean block_disconnect_socket = false;
+ SelectionKey key;
+ }
+
+ private Peer setup_socket(SocketChannel chan) throws IOException {
+ chan.configureBlocking(false);
+ // Lightning tends to send a number of small messages back and forth between peers quickly, which Nagle is
+ // particularly bad at handling, so we disable it here.
+ chan.setOption(StandardSocketOptions.TCP_NODELAY, true);
+ long our_id;
+ synchronized (this) {
+ this.socket_id = this.socket_id + 1;
+ our_id = this.socket_id;
+ }
+
+ final Peer peer = new Peer();
+ SocketDescriptor descriptor = SocketDescriptor.new_impl(new SocketDescriptor.SocketDescriptorInterface() {
+ @Override
+ public long send_data(byte[] data, boolean resume_read) {
+ if (resume_read) {
+ peer.key.interestOps(peer.key.interestOps() | SelectionKey.OP_READ);
+ }
+ try {
+ long written = chan.write(ByteBuffer.wrap(data));
+ if (written != data.length) {
+ peer.key.interestOps(peer.key.interestOps() | SelectionKey.OP_WRITE);
+ }
+ return written;
+ } catch (IOException e) {
+ // Most likely the socket is disconnected, let the background thread handle it.
+ return 0;
+ }
+ }
+
+ @Override
+ public void disconnect_socket() {
+ try {
+ peer.key.cancel();
+ peer.key.channel().close();
+ selector.wakeup();
+ } catch (IOException ignored) { }
+ synchronized (peer) {
+ while (peer.block_disconnect_socket) {
+ try {
+ peer.wait();
+ } catch (InterruptedException ignored) { }
+ }
+ }
+ }
+ @Override public boolean eq(SocketDescriptor other_arg) { return other_arg.hash() == our_id; }
+ @Override public long hash() { return our_id; }
+ });
+ peer.descriptor = descriptor;
+ return peer;
+ }
+
+ PeerManager peer_manager;
+ Thread io_thread;
+ Selector selector;
+ long socket_id;
+ volatile boolean shutdown = false;
+
+ /**
+ * Constructs a new peer handler, spawning a thread to monitor for socket events.
+ * The background thread will call the PeerManager's timer_tick_occured() function for you on an appropriate schedule.
+ *
+ * @param manager The LDK PeerManager which connection data will be provided to.
+ * @throws IOException If an internal java.nio error occurs.
+ */
+ public NioPeerHandler(PeerManager manager) throws IOException {
+long id = manager._test_only_get_ptr();
+ this.peer_manager = manager;
+ this.selector = Selector.open();
+ io_thread = new Thread(() -> {
+ ByteBuffer buf = ByteBuffer.allocate(8192);
+ long lastTimerTick = System.currentTimeMillis();
+ while (true) {
+ try {
+ this.selector.select(1000);
+ } catch (IOException ignored) {
+ System.err.println("java.nio threw an unexpected IOException. Stopping PeerHandler thread!");
+ return;
+ }
+ if (shutdown) return;
+ if (Thread.interrupted()) return;
+ for (SelectionKey key : this.selector.selectedKeys()) {
+ if ((key.interestOps() & SelectionKey.OP_ACCEPT) != 0) {
+ if (key.isAcceptable()) {
+ SocketChannel chan;
+ try {
+ chan = ((ServerSocketChannel) key.channel()).accept();
+ } catch (IOException ignored) {
+ key.cancel();
+ continue;
+ }
+ if (chan == null) continue;
+ try {
+ Peer peer = setup_socket(chan);
+ Result_NonePeerHandleErrorZ res = this.peer_manager.new_inbound_connection(peer.descriptor);
+ if (res instanceof Result_NonePeerHandleErrorZ.Result_NonePeerHandleErrorZ_OK) {
+ peer.key = chan.register(this.selector, SelectionKey.OP_READ, peer);
+ }
+ } catch (IOException ignored) { }
+ }
+ continue; // There is no attachment so the rest of the loop is useless
+ }
+ Peer peer = (Peer) key.attachment();
+ synchronized (peer) {
+ peer.block_disconnect_socket = true;
+ }
+ try {
+ if (key.isValid() && (key.interestOps() & SelectionKey.OP_WRITE) != 0 && key.isWritable()) {
+ Result_NonePeerHandleErrorZ res = this.peer_manager.write_buffer_space_avail(peer.descriptor);
+ if (res instanceof Result_NonePeerHandleErrorZ.Result_NonePeerHandleErrorZ_Err) {
+ key.channel().close();
+ key.cancel();
+ }
+ }
+ if (key.isValid() && (key.interestOps() & SelectionKey.OP_READ) != 0 && key.isReadable()) {
+ buf.clear();
+ int read = ((SocketChannel) key.channel()).read(buf);
+ if (read == -1) {
+ this.peer_manager.socket_disconnected(peer.descriptor);
+ key.cancel();
+ } else if (read > 0) {
+ buf.flip();
+ byte[] read_bytes = new byte[read];
+ buf.get(read_bytes, 0, read);
+ Result_boolPeerHandleErrorZ res = this.peer_manager.read_event(peer.descriptor, read_bytes);
+ if (res instanceof Result_boolPeerHandleErrorZ.Result_boolPeerHandleErrorZ_OK) {
+ if (((Result_boolPeerHandleErrorZ.Result_boolPeerHandleErrorZ_OK) res).res) {
+ key.interestOps(key.interestOps() & (~SelectionKey.OP_READ));
+ }
+ } else {
+ key.channel().close();
+ key.cancel();
+ }
+ }
+ }
+ } catch (IOException ignored) {
+ try { key.channel().close(); } catch (IOException ignored2) { }
+ key.cancel();
+ peer_manager.socket_disconnected(peer.descriptor);
+ }
+ synchronized (peer) {
+ peer.block_disconnect_socket = false;
+ peer.notifyAll();
+ }
+ }
+ if (lastTimerTick < System.currentTimeMillis() - 30 * 1000) {
+ peer_manager.timer_tick_occured();
+ lastTimerTick = System.currentTimeMillis();
+ }
+ peer_manager.process_events();
+ }
+ }, "NioPeerHandler NIO Thread");
+ io_thread.start();
+ }
+
+ /**
+ * Connect to a peer given their node id and socket address. Blocks until a connection is established (or returns
+ * IOException) and then the connection handling runs in the background.
+ *
+ * @param their_node_id A valid 33-byte public key representing the peer's Lightning Node ID. If this is invalid,
+ * undefined behavior (read: Segfault, etc) may occur.
+ * @param remote The socket address to connect to.
+ * @throws IOException If connecting to the remote endpoint fails or internal java.nio errors occur.
+ */
+ public void connect(byte[] their_node_id, SocketAddress remote) throws IOException {
+ SocketChannel chan = SocketChannel.open(remote);
+ Peer peer = setup_socket(chan);
+ Result_CVec_u8ZPeerHandleErrorZ res = this.peer_manager.new_outbound_connection(their_node_id, peer.descriptor);
+ if (res instanceof Result_CVec_u8ZPeerHandleErrorZ.Result_CVec_u8ZPeerHandleErrorZ_OK) {
+ byte[] initial_bytes = ((Result_CVec_u8ZPeerHandleErrorZ.Result_CVec_u8ZPeerHandleErrorZ_OK) res).res;
+ if (chan.write(ByteBuffer.wrap(initial_bytes)) != initial_bytes.length) {
+ throw new IOException("We assume TCP socket buffer is at least a single packet in length");
+ }
+ peer.key = chan.register(this.selector, SelectionKey.OP_READ, peer);
+ this.selector.wakeup();
+ } else {
+ throw new IOException("LDK rejected outbound connection. This likely shouldn't ever happen.");
+ }
+ }
+
+ /**
+ * Binds a listening socket to the given address, accepting incoming connections and handling them on the background
+ * thread.
+ *
+ * @param socket_address The address to bind the listening socket to.
+ * @throws IOException if binding the listening socket fail.
+ */
+ public void bind_listener(SocketAddress socket_address) throws IOException {
+ ServerSocketChannel listen_channel = ServerSocketChannel.open();
+ listen_channel.bind(socket_address);
+ listen_channel.configureBlocking(false);
+ listen_channel.register(this.selector, SelectionKey.OP_ACCEPT);
+ this.selector.wakeup();
+ }
+
+ /**
+ * Interrupt the background thread, stopping all peer handling. Disconnection events to the PeerHandler are not made,
+ * potentially leaving the PeerHandler in an inconsistent state.
+ */
+ public void interrupt() {
+ shutdown = true;
+ selector.wakeup();
+ try {
+ io_thread.join();
+ } catch (InterruptedException ignored) { }
+ }
+
+ /**
+ * Calls process_events on the PeerManager immediately. Normally process_events is polled regularly to check for new
+ * messages which need to be sent, but you can interrupt the poll and check immediately by calling this function.
+ */
+ public void check_events() {
+ selector.wakeup();
+ }
+}
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projects / ldk-java / blobdiff