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

   1 package org.ldk.batteries;
   2
   3 import org.ldk.impl.bindings;
   4 import org.ldk.structs.*;
   5
   6 import java.io.IOException;
   7 import java.lang.reflect.Field;
   8 import java.lang.ref.Reference;
   9 import java.lang.reflect.InvocationTargetException;
  10 import java.lang.reflect.Method;
  11 import java.net.*;
  12 import java.util.LinkedList;
  13 import java.nio.Buffer;
  14 import java.nio.ByteBuffer;
  15 import java.nio.channels.*;
  16
  17 /**
  18  * A NioPeerHandler maps LDK's PeerHandler to Java's NIO I/O interface. It spawns a single background thread which
  19  * processes socket events and provides the data to LDK for decryption and processing.
  20  */
  21 public class NioPeerHandler {
  22     private static class Peer {
  23         SocketDescriptor descriptor;
  24         SelectionKey key;
  25     }
  26
  27     // Android's java.nio implementation has a big lock inside the selector, preventing any concurrent access to it.
  28     // This appears to largely defeat the entire purpose of java.nio, but we work around it here by explicitly checking
  29     // for an Android environment and passing any selector access on any thread other than our internal one through
  30     // do_selector_action, which wakes up the selector before accessing it.
  31     private static boolean IS_ANDROID;
  32     static {
  33         IS_ANDROID = System.getProperty("java.vendor").toLowerCase().contains("android");
  34     }
  35     private boolean wakeup_selector = false;
  36     private interface SelectorCall {
  37         void meth() throws IOException;
  38     }
  39     private void do_selector_action(SelectorCall meth) throws IOException {
  40         if (IS_ANDROID) {
  41             wakeup_selector = true;
  42             this.selector.wakeup();
  43             synchronized (this.selector) {
  44                 meth.meth();
  45                 wakeup_selector = false;
  46             }
  47         } else {
  48             meth.meth();
  49         }
  50     }
  51
  52     static private Method ResultBoolPeerHandleError_Free;
  53     static {
  54         try {
  55             Class c = Result_boolPeerHandleErrorZ.class;
  56             ResultBoolPeerHandleError_Free = c.getDeclaredMethod("force_free");
  57             ResultBoolPeerHandleError_Free.setAccessible(true);
  58         } catch (NoSuchMethodException e) {
  59             throw new IllegalArgumentException(
  60                     "We currently use reflection to access protected fields as Java has no reasonable access controls", e);
  61         }
  62     }
  63
  64     private Peer setup_socket(SocketChannel chan) throws IOException {
  65         chan.configureBlocking(false);
  66         // Lightning tends to send a number of small messages back and forth between peers quickly, which Nagle is
  67         // particularly bad at handling, so we disable it here.
  68         chan.setOption(StandardSocketOptions.TCP_NODELAY, true);
  69         long our_id;
  70         synchronized (this) {
  71             this.socket_id = this.socket_id + 1;
  72             our_id = this.socket_id;
  73         }
  74
  75         final Peer peer = new Peer();
  76         SocketDescriptor descriptor = SocketDescriptor.new_impl(new SocketDescriptor.SocketDescriptorInterface() {
  77             @Override
  78             public long send_data(byte[] data, boolean resume_read) {
  79                 try {
  80                     long written = chan.write(ByteBuffer.wrap(data));
  81                     if (written != data.length) {
  82                         do_selector_action(() -> peer.key.interestOps(
  83                                                         (peer.key.interestOps() | SelectionKey.OP_WRITE) & (~SelectionKey.OP_READ)));
  84                     } else if (resume_read) {
  85                         do_selector_action(() -> peer.key.interestOps(
  86                                                         (peer.key.interestOps() | SelectionKey.OP_READ) & (~SelectionKey.OP_WRITE)));
  87                                         }
  88                     return written;
  89                 } catch (IOException|CancelledKeyException ignored) {
  90                     // Most likely the socket is disconnected, let the background thread handle it.
  91                     return 0;
  92                 }
  93             }
  94
  95             @Override
  96             public void disconnect_socket() {
  97                 try {
  98                     do_selector_action(() -> {
  99                         try { peer.key.cancel(); } catch (CancelledKeyException ignored) {}
 100                         peer.key.channel().close();
 101                     });
 102                 } catch (IOException ignored) { }
 103             }
 104             @Override public boolean eq(SocketDescriptor other_arg) { return other_arg.hash() == our_id; }
 105             @Override public long hash() { return our_id; }
 106         });
 107         peer.descriptor = descriptor;
 108         return peer;
 109     }
 110
 111     PeerManager peer_manager;
 112     Thread io_thread;
 113     final Selector selector;
 114     long socket_id;
 115     volatile boolean shutdown = false;
 116
 117     private static Option_SocketAddressZ get_netaddr_from_sockaddr(java.net.SocketAddress sockaddr) {
 118         if (sockaddr instanceof InetSocketAddress) {
 119             InetAddress addr = ((InetSocketAddress) sockaddr).getAddress();
 120             short port = (short) ((InetSocketAddress) sockaddr).getPort();
 121             if (addr instanceof Inet4Address) {
 122                 return Option_SocketAddressZ.some(org.ldk.structs.SocketAddress.tcp_ip_v4(addr.getAddress(), port));
 123             } else if (addr instanceof Inet6Address) {
 124                 return Option_SocketAddressZ.some(org.ldk.structs.SocketAddress.tcp_ip_v6(addr.getAddress(), port));
 125             }
 126         }
 127         return Option_SocketAddressZ.none();
 128     }
 129
 130     /**
 131      * Constructs a new peer handler, spawning a thread to monitor for socket events.
 132      *
 133      * @param manager The LDK PeerManager which connection data will be provided to.
 134      * @throws IOException If an internal java.nio error occurs.
 135      */
 136     public NioPeerHandler(PeerManager manager) throws IOException {
 137         this.peer_manager = manager;
 138         this.selector = Selector.open();
 139         io_thread = new Thread(() -> {
 140             int BUF_SZ = 16 * 1024;
 141             byte[] max_buf_byte_object = new byte[BUF_SZ];
 142             ByteBuffer buf = ByteBuffer.allocate(BUF_SZ);
 143
 144             while (true) {
 145                 try {
 146                     if (IS_ANDROID) {
 147                         while (true) {
 148                             synchronized (this.selector) {
 149                                 if (!wakeup_selector) {
 150                                     this.selector.select(1000);
 151                                     break;
 152                                 }
 153                             }
 154                         }
 155                     } else {
 156                         this.selector.select(1000);
 157                     }
 158                 } catch (IOException ignored) {
 159                     System.err.println("java.nio threw an unexpected IOException. Stopping PeerHandler thread!");
 160                     return;
 161                 }
 162                 if (shutdown) return;
 163                 if (Thread.interrupted()) return;
 164                 for (SelectionKey key : this.selector.selectedKeys()) {
 165                     try {
 166                         if ((key.interestOps() & SelectionKey.OP_ACCEPT) != 0) {
 167                             if (key.isAcceptable()) {
 168                                 SocketChannel chan;
 169                                 try {
 170                                     chan = ((ServerSocketChannel) key.channel()).accept();
 171                                 } catch (IOException ignored) {
 172                                     key.cancel();
 173                                     continue;
 174                                 }
 175                                 if (chan == null) continue;
 176                                 try {
 177                                     Peer peer = setup_socket(chan);
 178                                     peer.key = chan.register(this.selector, SelectionKey.OP_READ, peer);
 179                                     Option_SocketAddressZ netaddr = get_netaddr_from_sockaddr(chan.getRemoteAddress());
 180                                     Result_NonePeerHandleErrorZ res = this.peer_manager.new_inbound_connection(peer.descriptor, netaddr);
 181                                     if (res instanceof Result_NonePeerHandleErrorZ.Result_NonePeerHandleErrorZ_Err) {
 182                                                                                 peer.descriptor.disconnect_socket();
 183                                                                         }
 184                                 } catch (IOException ignored) { }
 185                             }
 186                             continue; // There is no attachment so the rest of the loop is useless
 187                         }
 188                         Peer peer = (Peer) key.attachment();
 189                         try {
 190                             if (key.isValid() && (key.interestOps() & SelectionKey.OP_WRITE) != 0 && key.isWritable()) {
 191                                 Result_NonePeerHandleErrorZ res = this.peer_manager.write_buffer_space_avail(peer.descriptor);
 192                                 if (res instanceof Result_NonePeerHandleErrorZ.Result_NonePeerHandleErrorZ_Err) {
 193                                     key.cancel();
 194                                     key.channel().close();
 195                                 }
 196                             }
 197                             if (key.isValid() && (key.interestOps() & SelectionKey.OP_READ) != 0 && key.isReadable()) {
 198                                 ((Buffer)buf).clear();
 199                                 int read = ((SocketChannel) key.channel()).read(buf);
 200                                 if (read == -1) {
 201                                     this.peer_manager.socket_disconnected(peer.descriptor);
 202                                     key.cancel();
 203                                     key.channel().close(); // This may throw, we read -1 so the channel should already be closed, but do this to be safe
 204                                 } else if (read > 0) {
 205                                     ((Buffer)buf).flip();
 206                                     byte[] read_bytes;
 207                                     if (read == BUF_SZ) {
 208                                         read_bytes = max_buf_byte_object;
 209                                     } else {
 210                                         read_bytes = new byte[read];
 211                                     }
 212                                     buf.get(read_bytes, 0, read);
 213                                     Result_boolPeerHandleErrorZ read_res = this.peer_manager.read_event(peer.descriptor, read_bytes);
 214                                     if (read_res instanceof Result_boolPeerHandleErrorZ.Result_boolPeerHandleErrorZ_OK) {
 215                                         if (((Result_boolPeerHandleErrorZ.Result_boolPeerHandleErrorZ_OK) read_res).res) {
 216                                             key.interestOps(key.interestOps() & (~SelectionKey.OP_READ));
 217                                         }
 218                                         // Force the read_res to drop its native memory early (before finalize()) as this is
 219                                         // pretty hot and we don't want to bloat native memory too long.
 220                                         // Note that we only do this in the Ok case as its more trivially safe, the Err
 221                                         // case has nested structs which will also free and may be confused if their pointer
 222                                         // is dropped out from under them.
 223                                         try { ResultBoolPeerHandleError_Free.invoke(read_res); } catch (Exception ignored) {}
 224                                     } else {
 225                                         key.cancel();
 226                                         key.channel().close();
 227                                     }
 228                                 }
 229                             }
 230                         } catch (IOException ignored) {
 231                             key.cancel();
 232                             try { key.channel().close(); } catch (IOException ignored2) { }
 233                             peer_manager.socket_disconnected(peer.descriptor);
 234                         }
 235                     } catch (CancelledKeyException e) {
 236                         try { key.channel().close(); } catch (IOException ignored) { }
 237                         // The key is only cancelled when we have notified the PeerManager that the socket is closed, so
 238                         // no need to do anything here with the PeerManager.
 239                     }
 240                 }
 241                 peer_manager.process_events();
 242             }
 243         }, "NioPeerHandler NIO Thread");
 244         io_thread.start();
 245     }
 246
 247     /**
 248      * Connect to a peer given their node id and socket address. Blocks until a connection is established (or returns
 249      * IOException) and then the connection handling runs in the background.
 250      *
 251      * @param their_node_id A valid 33-byte public key representing the peer's Lightning Node ID. If this is invalid,
 252      *                      undefined behavior (read: Segfault, etc) may occur.
 253      * @param remote The socket address to connect to.
 254      * @param timeout_ms The amount of time, in milliseconds, up to which we will wait for connection to complete.
 255      * @throws IOException If connecting to the remote endpoint fails or internal java.nio errors occur.
 256      */
 257     public void connect(byte[] their_node_id, java.net.SocketAddress remote, int timeout_ms) throws IOException {
 258         SocketChannel chan = SocketChannel.open();
 259         boolean connected;
 260         try {
 261             chan.configureBlocking(false);
 262             Selector open_selector = Selector.open();
 263             chan.register(open_selector, SelectionKey.OP_CONNECT);
 264             if (!chan.connect(remote)) {
 265                 open_selector.select(timeout_ms);
 266             }
 267             connected = chan.finishConnect();
 268         } catch (IOException e) {
 269             try { chan.close(); } catch (IOException _e) { }
 270             throw e;
 271         }
 272         if (!connected) {
 273             try { chan.close(); } catch (IOException _e) { }
 274             throw new IOException("Timed out");
 275         }
 276         Peer peer = setup_socket(chan);
 277         do_selector_action(() -> peer.key = chan.register(this.selector, SelectionKey.OP_READ, peer));
 278         Result_CVec_u8ZPeerHandleErrorZ res = this.peer_manager.new_outbound_connection(their_node_id, peer.descriptor, get_netaddr_from_sockaddr(remote));
 279         if (res instanceof  Result_CVec_u8ZPeerHandleErrorZ.Result_CVec_u8ZPeerHandleErrorZ_OK) {
 280             byte[] initial_bytes = ((Result_CVec_u8ZPeerHandleErrorZ.Result_CVec_u8ZPeerHandleErrorZ_OK) res).res;
 281             if (chan.write(ByteBuffer.wrap(initial_bytes)) != initial_bytes.length) {
 282                 peer.descriptor.disconnect_socket();
 283                 this.peer_manager.socket_disconnected(peer.descriptor);
 284                 throw new IOException("We assume TCP socket buffer is at least a single packet in length");
 285             }
 286         } else {
 287             peer.descriptor.disconnect_socket();
 288             throw new IOException("LDK rejected outbound connection. This likely shouldn't ever happen.");
 289         }
 290     }
 291
 292     /**
 293      * Disconnects any connections currently open with the peer with the given node id.
 294      *
 295      * @param their_node_id must be a valid 33-byte public key
 296      */
 297     public void disconnect(byte[] their_node_id) {
 298         this.peer_manager.disconnect_by_node_id(their_node_id);
 299     }
 300
 301     /**
 302      * Before shutdown, we have to ensure all of our listening sockets are closed manually, as they appear
 303      * to otherwise remain open and lying around on OSX (though no other platform).
 304      */
 305     private LinkedList<ServerSocketChannel> listening_sockets = new LinkedList();
 306     /**
 307      * Binds a listening socket to the given address, accepting incoming connections and handling them on the background
 308      * thread.
 309      *
 310      * @param socket_address The address to bind the listening socket to.
 311      * @throws IOException if binding the listening socket fail.
 312      */
 313     public void bind_listener(java.net.SocketAddress socket_address) throws IOException {
 314         ServerSocketChannel listen_channel = ServerSocketChannel.open();
 315         listen_channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
 316         listen_channel.bind(socket_address);
 317         listen_channel.configureBlocking(false);
 318         do_selector_action(() -> listen_channel.register(this.selector, SelectionKey.OP_ACCEPT));
 319         synchronized(listening_sockets) {
 320             listening_sockets.add(listen_channel);
 321         }
 322     }
 323
 324     /**
 325      * Interrupt the background thread, stopping all peer handling.
 326      *
 327      * After this method is called, the behavior of future calls to methods on this NioPeerHandler are undefined.
 328      */
 329     public void interrupt() {
 330         this.peer_manager.disconnect_all_peers();
 331         shutdown = true;
 332         selector.wakeup();
 333         try {
 334             io_thread.join();
 335         } catch (InterruptedException ignored) { }
 336         synchronized(listening_sockets) {
 337             try {
 338                 selector.close();
 339                 for (ServerSocketChannel chan : listening_sockets) {
 340                     chan.close();
 341                 }
 342                 listening_sockets.clear();
 343             } catch (IOException ignored) {}
 344         }
 345         Reference.reachabilityFence(this.peer_manager); // Almost certainly overkill, but no harm in it
 346     }
 347
 348     /**
 349      * Calls process_events on the PeerManager immediately. Normally process_events is polled regularly to check for new
 350      * messages which need to be sent, but you can interrupt the poll and check immediately by calling this function.
 351      */
 352     public void check_events() {
 353         selector.wakeup();
 354     }
 355 }