/**
* Validate an expected handshake on a connection.
*
* <p>Reads an expected handshake message from the given connected socket, parses it and validates
* that the torrent hash_info corresponds to the torrent we're sharing, and that the peerId
* matches the peer ID we expect to see coming from the remote peer.
*
* @param socket The connected socket to the remote peer.
* @param peerId The peer ID we expect in the handshake. If <em>null</em>, any peer ID is accepted
* (this is the case for incoming connections).
* @return The validated handshake message object.
*/
private Handshake validateHandshake(Socket socket, byte[] peerId)
throws IOException, ParseException {
InputStream is = socket.getInputStream();
// Read the handshake from the wire
int pstrlen = is.read();
byte[] data = new byte[Handshake.BASE_HANDSHAKE_LENGTH + pstrlen];
data[0] = (byte) pstrlen;
is.read(data, 1, data.length - 1);
// Parse and check the handshake
Handshake hs = Handshake.parse(ByteBuffer.wrap(data));
if (!Arrays.equals(hs.getInfoHash(), this.torrent.getInfoHash())) {
throw new ParseException(
"Handshake for unknow torrent "
+ Torrent.byteArrayToHexString(hs.getInfoHash())
+ " from "
+ this.socketRepr(socket)
+ ".",
pstrlen + 9);
}
if (peerId != null && !Arrays.equals(hs.getPeerId(), peerId)) {
throw new ParseException(
"Announced peer ID "
+ Torrent.byteArrayToHexString(hs.getPeerId())
+ " did not match expected peer ID "
+ Torrent.byteArrayToHexString(peerId)
+ ".",
pstrlen + 29);
}
return hs;
}
@Override
public void run() {
Socket socket = new Socket();
InetSocketAddress address = new InetSocketAddress(this.peer.getIp(), this.peer.getPort());
try {
logger.info("Connecting to {}...", this.peer);
socket.connect(address, 3 * 1000);
this.handler.sendHandshake(socket);
Handshake hs =
this.handler.validateHandshake(
socket, (this.peer.hasPeerId() ? this.peer.getPeerId().array() : null));
logger.info(
"Handshaked with {}, peer ID is {}.",
this.peer,
Torrent.byteArrayToHexString(hs.getPeerId()));
this.handler.fireNewPeerConnection(socket, hs.getPeerId());
} catch (IOException ioe) {
try {
socket.close();
} catch (IOException e) {
}
this.handler.fireFailedConnection(this.peer, ioe);
} catch (ParseException pe) {
try {
socket.close();
} catch (IOException e) {
}
this.handler.fireFailedConnection(this.peer, pe);
}
}
/**
* Accept the next incoming connection.
*
* <p>When a new peer connects to this service, wait for it to send its handshake. We then parse
* and check that the handshake advertises the torrent hash we expect, then reply with our own
* handshake.
*
* <p>If everything goes according to plan, notify the <code>IncomingConnectionListener</code>s
* with the connected socket and the parsed peer ID.
*/
private void accept() throws IOException, SocketTimeoutException {
Socket socket = this.socket.accept();
try {
logger.debug("New incoming connection ...");
Handshake hs = this.validateHandshake(socket, null);
this.sendHandshake(socket);
this.fireNewPeerConnection(socket, hs.getPeerId());
} catch (ParseException pe) {
logger.debug("Invalid handshake from {}: {}", this.socketRepr(socket), pe.getMessage());
try {
socket.close();
} catch (IOException e) {
}
} catch (IOException ioe) {
logger.debug(
"An error occured while reading an incoming " + "handshake: {}", ioe.getMessage());
try {
if (!socket.isClosed()) {
socket.close();
}
} catch (IOException e) {
// Ignore
}
}
}
