/// <summary>
/// Connect to the given IP address using the port specified as part of the network parameters. Once construction
/// is complete a functioning network channel is set up and running.
/// </summary>
/// <param name="peerAddress">IP address to connect to. IPv6 is not currently supported by BitCoin. If port is not positive the default port from params is used.</param>
/// <param name="params">Defines which network to connect to and details of the protocol.</param>
/// <param name="bestHeight">How many blocks are in our best chain</param>
/// <param name="connectTimeout">Timeout in milliseconds when initially connecting to peer</param>
/// <exception cref="IOException">If there is a network related failure.</exception>
/// <exception cref="ProtocolException">If the version negotiation failed.</exception>
public NetworkConnection(PeerAddress peerAddress, NetworkParameters @params, uint bestHeight, int connectTimeout)
{
_params = @params;
_remoteIp = peerAddress.Addr;
var port = (peerAddress.Port > 0) ? peerAddress.Port : @params.Port;
var address = new IPEndPoint(_remoteIp, port);
_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
_socket.Connect(address);
_socket.SendTimeout = _socket.ReceiveTimeout = connectTimeout;
_out = new NetworkStream(_socket, FileAccess.Write);
_in = new NetworkStream(_socket, FileAccess.Read);
// the version message never uses check-summing. Update check-summing property after version is read.
_serializer = new BitcoinSerializer(@params, false);
// Announce ourselves. This has to come first to connect to clients beyond v0.30.20.2 which wait to hear
// from us until they send their version message back.
WriteMessage(new VersionMessage(@params, bestHeight));
// When connecting, the remote peer sends us a version message with various bits of
// useful data in it. We need to know the peer protocol version before we can talk to it.
_versionMessage = (VersionMessage) ReadMessage();
// Now it's our turn ...
// Send an ACK message stating we accept the peers protocol version.
WriteMessage(new VersionAck());
// And get one back ...
ReadMessage();
// Switch to the new protocol version.
var peerVersion = _versionMessage.ClientVersion;
_log.InfoFormat("Connected to peer: version={0}, subVer='{1}', services=0x{2:X}, time={3}, blocks={4}",
peerVersion,
_versionMessage.SubVer,
_versionMessage.LocalServices,
UnixTime.FromUnixTime(_versionMessage.Time),
_versionMessage.BestHeight
);
// BitCoinSharp is a client mode implementation. That means there's not much point in us talking to other client
// mode nodes because we can't download the data from them we need to find/verify transactions.
if (!_versionMessage.HasBlockChain())
{
// Shut down the socket
try
{
Shutdown();
}
catch (IOException)
{
// ignore exceptions while aborting
}
throw new ProtocolException("Peer does not have a copy of the block chain.");
}
// newer clients use check-summing
_serializer.UseChecksumming(peerVersion >= 209);
// Handshake is done!
}
public VersionMessage(NetworkParameters @params, uint newBestHeight)
: base(@params)
{
ClientVersion = NetworkParameters.ProtocolVersion;
LocalServices = 0;
Time = UnixTime.ToUnixTime(DateTime.UtcNow);
// Note that the official client doesn't do anything with these, and finding out your own external IP address
// is kind of tricky anyway, so we just put nonsense here for now.
MyAddr = new PeerAddress(IPAddress.Loopback, @params.Port, 0);
TheirAddr = new PeerAddress(IPAddress.Loopback, @params.Port, 0);
SubVer = "BitCoinSharp 0.1";
BestHeight = newBestHeight;
}
/// <exception cref="BitCoinSharp.ProtocolException" />
protected override void Parse()
{
ClientVersion = ReadUint32();
LocalServices = ReadUint64();
Time = ReadUint64();
MyAddr = new PeerAddress(Params, Bytes, Cursor, 0);
Cursor += MyAddr.MessageSize;
TheirAddr = new PeerAddress(Params, Bytes, Cursor, 0);
Cursor += TheirAddr.MessageSize;
// uint64 localHostNonce (random data)
// We don't care about the localhost nonce. It's used to detect connecting back to yourself in cases where
// there are NATs and proxies in the way. However we don't listen for inbound connections so it's irrelevant.
_localHostNonce = ReadUint64();
// string subVer (currently "")
SubVer = ReadStr();
// int bestHeight (size of known block chain).
BestHeight = ReadUint32();
}
/// <exception cref="ProtocolException"/>
protected override void Parse()
{
var numAddresses = ReadVarInt();
// Guard against ultra large messages that will crash us.
if (numAddresses > _maxAddresses)
throw new ProtocolException("Address message too large.");
Addresses = new List<PeerAddress>((int) numAddresses);
for (var i = 0UL; i < numAddresses; i++)
{
var addr = new PeerAddress(Params, Bytes, Cursor, ProtocolVersion);
Addresses.Add(addr);
Cursor += addr.MessageSize;
}
}
/// <summary>
/// Add an address to the list of potential peers to connect to.
/// </summary>
public void AddAddress(PeerAddress peerAddress)
{
// TODO(miron) consider de-duplication
_inactives.Add(peerAddress);
}
