_ Git - ldk-java/blob - src/main/java/org/ldk/batteries/NioPeerHandler.java

   1 package org.ldk.batteries;
   2
   3 import org.ldk.structs.*;
   4
   5 import java.io.IOException;
   6 import java.net.SocketAddress;
   7 import java.net.StandardSocketOptions;
   8 import java.nio.ByteBuffer;
   9 import java.nio.channels.SelectionKey;
  10 import java.nio.channels.Selector;
  11 import java.nio.channels.ServerSocketChannel;
  12 import java.nio.channels.SocketChannel;
  13
  14 public class NioPeerHandler {
  15     private static class Peer {
  16         SocketDescriptor descriptor;
  17         // When we are told by LDK to disconnect, we can't return to LDK until we are sure
  18         // won't call any more read/write PeerManager functions with the same connection.
  19         // This is set to true if we're in such a condition (with disconnect checked
  20         // before with the Peer monitor lock held) and false when we can return.
  21         boolean block_disconnect_socket = false;
  22         SelectionKey key;
  23     }
  24
  25     private Peer setup_socket(SocketChannel chan) throws IOException {
  26         chan.configureBlocking(false);
  27         // Lightning tends to send a number of small messages back and forth between peers quickly, which Nagle is
  28         // particularly bad at handling, so we disable it here.
  29         chan.setOption(StandardSocketOptions.TCP_NODELAY, true);
  30         long our_id;
  31         synchronized (this) {
  32             this.socket_id = this.socket_id + 1;
  33             our_id = this.socket_id;
  34         }
  35
  36         final Peer peer = new Peer();
  37         SocketDescriptor descriptor = SocketDescriptor.new_impl(new SocketDescriptor.SocketDescriptorInterface() {
  38             @Override
  39             public long send_data(byte[] data, boolean resume_read) {
  40                 if (resume_read) {
  41                     peer.key.interestOps(peer.key.interestOps() | SelectionKey.OP_READ);
  42                 }
  43                 try {
  44                     long written = chan.write(ByteBuffer.wrap(data));
  45                     if (written != data.length) {
  46                         peer.key.interestOps(peer.key.interestOps() | SelectionKey.OP_WRITE);
  47                     }
  48                     return written;
  49                 } catch (IOException e) {
  50                     // Most likely the socket is disconnected, let the background thread handle it.
  51                     return 0;
  52                 }
  53             }
  54
  55             @Override
  56             public void disconnect_socket() {
  57                 try {
  58                     peer.key.cancel();
  59                     peer.key.channel().close();
  60                     selector.wakeup();
  61                 } catch (IOException ignored) { }
  62                 synchronized (peer) {
  63                     while (peer.block_disconnect_socket) {
  64                         try {
  65                             peer.wait();
  66                         } catch (InterruptedException ignored) { }
  67                     }
  68                 }
  69             }
  70             @Override public boolean eq(SocketDescriptor other_arg) { return other_arg.hash() == our_id; }
  71             @Override public long hash() { return our_id; }
  72         });
  73         peer.descriptor = descriptor;
  74         return peer;
  75     }
  76
  77     PeerManager peer_manager;
  78     Thread io_thread;
  79     Selector selector;
  80     long socket_id;
  81     volatile boolean shutdown = false;
  82
  83     /**
  84      * Constructs a new peer handler, spawning a thread to monitor for socket events.
  85      * The background thread will call the PeerManager's timer_tick_occured() function for you on an appropriate schedule.
  86      *
  87      * @param manager The LDK PeerManager which connection data will be provided to.
  88      * @throws IOException If an internal java.nio error occurs.
  89      */
  90     public NioPeerHandler(PeerManager manager) throws IOException {
  91 long id = manager._test_only_get_ptr();
  92         this.peer_manager = manager;
  93         this.selector = Selector.open();
  94         io_thread = new Thread(() -> {
  95             ByteBuffer buf = ByteBuffer.allocate(8192);
  96             long lastTimerTick = System.currentTimeMillis();
  97             while (true) {
  98                 try {
  99                     this.selector.select(1000);
 100                 } catch (IOException ignored) {
 101                     System.err.println("java.nio threw an unexpected IOException. Stopping PeerHandler thread!");
 102                     return;
 103                 }
 104                 if (shutdown) return;
 105                 if (Thread.interrupted()) return;
 106                 for (SelectionKey key : this.selector.selectedKeys()) {
 107                     if ((key.interestOps() & SelectionKey.OP_ACCEPT) != 0) {
 108                         if (key.isAcceptable()) {
 109                             SocketChannel chan;
 110                             try {
 111                                 chan = ((ServerSocketChannel) key.channel()).accept();
 112                             } catch (IOException ignored) {
 113                                 key.cancel();
 114                                 continue;
 115                             }
 116                             if (chan == null) continue;
 117                             try {
 118                                 Peer peer = setup_socket(chan);
 119                                 Result_NonePeerHandleErrorZ res = this.peer_manager.new_inbound_connection(peer.descriptor);
 120                                 if (res instanceof  Result_NonePeerHandleErrorZ.Result_NonePeerHandleErrorZ_OK) {
 121                                     peer.key = chan.register(this.selector, SelectionKey.OP_READ, peer);
 122                                 }
 123                             } catch (IOException ignored) { }
 124                         }
 125                         continue; // There is no attachment so the rest of the loop is useless
 126                     }
 127                     Peer peer = (Peer) key.attachment();
 128                     synchronized (peer) {
 129                         peer.block_disconnect_socket = true;
 130                     }
 131                     try {
 132                         if (key.isValid() && (key.interestOps() & SelectionKey.OP_WRITE) != 0 && key.isWritable()) {
 133                             Result_NonePeerHandleErrorZ res = this.peer_manager.write_buffer_space_avail(peer.descriptor);
 134                             if (res instanceof Result_NonePeerHandleErrorZ.Result_NonePeerHandleErrorZ_Err) {
 135                                 key.channel().close();
 136                                 key.cancel();
 137                             }
 138                         }
 139                         if (key.isValid() && (key.interestOps() & SelectionKey.OP_READ) != 0 && key.isReadable()) {
 140                             buf.clear();
 141                             int read = ((SocketChannel) key.channel()).read(buf);
 142                             if (read == -1) {
 143                                 this.peer_manager.socket_disconnected(peer.descriptor);
 144                                 key.cancel();
 145                             } else if (read > 0) {
 146                                 buf.flip();
 147                                 byte[] read_bytes = new byte[read];
 148                                 buf.get(read_bytes, 0, read);
 149                                 Result_boolPeerHandleErrorZ res = this.peer_manager.read_event(peer.descriptor, read_bytes);
 150                                 if (res instanceof Result_boolPeerHandleErrorZ.Result_boolPeerHandleErrorZ_OK) {
 151                                     if (((Result_boolPeerHandleErrorZ.Result_boolPeerHandleErrorZ_OK) res).res) {
 152                                         key.interestOps(key.interestOps() & (~SelectionKey.OP_READ));
 153                                     }
 154                                 } else {
 155                                     key.channel().close();
 156                                     key.cancel();
 157                                 }
 158                             }
 159                         }
 160                     } catch (IOException ignored) {
 161                         try { key.channel().close(); } catch (IOException ignored2) { }
 162                         key.cancel();
 163                         peer_manager.socket_disconnected(peer.descriptor);
 164                     }
 165                     synchronized (peer) {
 166                         peer.block_disconnect_socket = false;
 167                         peer.notifyAll();
 168                     }
 169                 }
 170                 if (lastTimerTick < System.currentTimeMillis() - 30 * 1000) {
 171                     peer_manager.timer_tick_occured();
 172                     lastTimerTick = System.currentTimeMillis();
 173                 }
 174                 peer_manager.process_events();
 175             }
 176         }, "NioPeerHandler NIO Thread");
 177         io_thread.start();
 178     }
 179
 180     /**
 181      * Connect to a peer given their node id and socket address. Blocks until a connection is established (or returns
 182      * IOException) and then the connection handling runs in the background.
 183      *
 184      * @param their_node_id A valid 33-byte public key representing the peer's Lightning Node ID. If this is invalid,
 185      *                      undefined behavior (read: Segfault, etc) may occur.
 186      * @param remote The socket address to connect to.
 187      * @throws IOException If connecting to the remote endpoint fails or internal java.nio errors occur.
 188      */
 189     public void connect(byte[] their_node_id, SocketAddress remote) throws IOException {
 190         SocketChannel chan = SocketChannel.open(remote);
 191         Peer peer = setup_socket(chan);
 192         Result_CVec_u8ZPeerHandleErrorZ res = this.peer_manager.new_outbound_connection(their_node_id, peer.descriptor);
 193         if (res instanceof  Result_CVec_u8ZPeerHandleErrorZ.Result_CVec_u8ZPeerHandleErrorZ_OK) {
 194             byte[] initial_bytes = ((Result_CVec_u8ZPeerHandleErrorZ.Result_CVec_u8ZPeerHandleErrorZ_OK) res).res;
 195             if (chan.write(ByteBuffer.wrap(initial_bytes)) != initial_bytes.length) {
 196                 throw new IOException("We assume TCP socket buffer is at least a single packet in length");
 197             }
 198             peer.key = chan.register(this.selector, SelectionKey.OP_READ, peer);
 199             this.selector.wakeup();
 200         } else {
 201             throw new IOException("LDK rejected outbound connection. This likely shouldn't ever happen.");
 202         }
 203     }
 204
 205     /**
 206      * Binds a listening socket to the given address, accepting incoming connections and handling them on the background
 207      * thread.
 208      *
 209      * @param socket_address The address to bind the listening socket to.
 210      * @throws IOException if binding the listening socket fail.
 211      */
 212     public void bind_listener(SocketAddress socket_address) throws IOException {
 213         ServerSocketChannel listen_channel = ServerSocketChannel.open();
 214         listen_channel.bind(socket_address);
 215         listen_channel.configureBlocking(false);
 216         listen_channel.register(this.selector, SelectionKey.OP_ACCEPT);
 217         this.selector.wakeup();
 218     }
 219
 220     /**
 221      * Interrupt the background thread, stopping all peer handling. Disconnection events to the PeerHandler are not made,
 222      * potentially leaving the PeerHandler in an inconsistent state.
 223      */
 224     public void interrupt() {
 225         shutdown = true;
 226         selector.wakeup();
 227         try {
 228             io_thread.join();
 229         } catch (InterruptedException ignored) { }
 230     }
 231
 232     /**
 233      * Calls process_events on the PeerManager immediately. Normally process_events is polled regularly to check for new
 234      * messages which need to be sent, but you can interrupt the poll and check immediately by calling this function.
 235      */
 236     public void check_events() {
 237         selector.wakeup();
 238     }
 239 }