/// <summary>
/// Sends "version" message to the peer and waits for the response in form of "verack" or "reject" message.
/// </summary>
/// <param name="cancellationToken">Cancellation that allows aborting the operation at any stage.</param>
/// <exception cref="ProtocolException">Thrown when the peer rejected our "version" message.</exception>
public async Task RespondToHandShakeAsync(CancellationToken cancellation = default(CancellationToken))
{
this.logger.LogTrace("()");
using (var listener = new NetworkPeerListener(this).Where(m => (m.Message.Payload is VerAckPayload) || (m.Message.Payload is RejectPayload)))
{
this.logger.LogTrace("Responding to handshake with my version.");
await this.SendMessageAsync(this.MyVersion);
this.logger.LogTrace("Waiting for version acknowledgement or rejection message.");
IncomingMessage message = listener.ReceiveMessage(cancellation);
if (message.Message.Payload is RejectPayload reject)
{
this.logger.LogTrace("Version rejected: code {0}, reason '{1}'.", reject.Code, reject.Reason);
this.logger.LogTrace("(-)[VERSION_REJECTED]");
throw new ProtocolException("Version rejected " + reject.Code + ": " + reject.Reason);
}
this.logger.LogTrace("Sending version acknowledgement.");
await this.SendMessageAsync(new VerAckPayload());
this.State = NetworkPeerState.HandShaked;
}
this.logger.LogTrace("(-)");
}
/// <summary>
/// Waits for a message of specific type to be received from the peer.
/// </summary>
/// <typeparam name="TPayload">Type of message to wait for.</typeparam>
/// <param name="cancellationToken">Cancellation that allows aborting the operation.</param>
/// <returns>Received message.</returns>
/// <exception cref="OperationCanceledException">Thrown if the cancellation token was cancelled.</exception>
public TPayload ReceiveMessage <TPayload>(CancellationToken cancellationToken = default(CancellationToken)) where TPayload : Payload
{
this.logger.LogTrace("()");
using (var listener = new NetworkPeerListener(this))
{
TPayload res = listener.ReceivePayload <TPayload>(cancellationToken);
this.logger.LogTrace("(-):'{0}'", res);
return(res);
}
}
/// <summary>
/// Exchanges "version" and "verack" messages with the peer.
/// <para>Both parties have to send their "version" messages to the other party
/// as well as to acknowledge that they are happy with the other party's "version" information.</para>
/// </summary>
/// <param name="requirements">Protocol requirement for network peers the node wants to be connected to.</param>
/// <param name="cancellationToken">Cancellation that allows aborting the operation at any stage.</param>
public async Task VersionHandshakeAsync(NetworkPeerRequirement requirements, CancellationToken cancellationToken)
{
this.logger.LogTrace("({0}.{1}:{2})", nameof(requirements), nameof(requirements.RequiredServices), requirements?.RequiredServices);
requirements = requirements ?? new NetworkPeerRequirement();
using (var listener = new NetworkPeerListener(this).Where(p => (p.Message.Payload is VersionPayload) ||
(p.Message.Payload is RejectPayload) ||
(p.Message.Payload is VerAckPayload)))
{
this.logger.LogTrace("Sending my version.");
await this.SendMessageAsync(this.MyVersion).ConfigureAwait(false);
this.logger.LogTrace("Waiting for version or rejection message.");
Payload payload = listener.ReceivePayload <Payload>(cancellationToken);
if (payload is RejectPayload)
{
this.logger.LogTrace("(-)[HANDSHAKE_REJECTED]");
throw new ProtocolException("Handshake rejected: " + ((RejectPayload)payload).Reason);
}
var version = (VersionPayload)payload;
this.PeerVersion = version;
if (!version.AddressReceiver.Address.Equals(this.MyVersion.AddressFrom.Address))
{
this.logger.LogDebug("Different external address detected by the node '{0}' instead of '{1}'.", version.AddressReceiver.Address, this.MyVersion.AddressFrom.Address);
}
if (version.Version < ProtocolVersion.MIN_PEER_PROTO_VERSION)
{
this.logger.LogDebug("Outdated version {0} received, disconnecting peer.", version.Version);
this.Disconnect("Outdated version");
this.logger.LogTrace("(-)[OUTDATED]");
return;
}
if (!requirements.Check(version))
{
this.logger.LogTrace("(-)[UNSUPPORTED_REQUIREMENTS]");
this.Disconnect("The peer does not support the required services requirement");
return;
}
this.logger.LogTrace("Sending version acknowledgement.");
await this.SendMessageAsync(new VerAckPayload()).ConfigureAwait(false);
this.logger.LogTrace("Waiting for version acknowledgement.");
listener.ReceivePayload <VerAckPayload>(cancellationToken);
this.State = NetworkPeerState.HandShaked;
if (this.Advertize && this.MyVersion.AddressFrom.Address.IsRoutable(true))
{
this.SendMessageVoidAsync(new AddrPayload(new NetworkAddress(this.MyVersion.AddressFrom)
{
Time = this.dateTimeProvider.GetTimeOffset()
}));
}
}
this.logger.LogTrace("(-)");
}
