// FIXME: this method is not safe from amplification attack
// maybe ping/pong/ping/pong is required
private async Task ReceiveFindPeerAsync(FindNeighbors findNeighbors)
{
if (!(findNeighbors.Remote is null))
{
await UpdateAsync(findNeighbors.Remote);
}
List <BoundPeer> found = _routing.Neighbors(findNeighbors.Target, BucketSize).ToList();
Neighbors neighbors = new Neighbors(found)
{
Identity = findNeighbors.Identity,
};
_swarm.ReplyMessage(neighbors);
}
private async Task <IEnumerable <BoundPeer> > GetNeighbors(
BoundPeer addressee,
Address target,
TimeSpan?timeout,
CancellationToken cancellationToken)
{
var findPeer = new FindNeighbors(target);
try
{
Message reply = await _transport.SendMessageWithReplyAsync(
addressee,
findPeer,
timeout,
cancellationToken
);
if (!(reply is Neighbors neighbors))
{
throw new InvalidMessageException(
$"Reply to {nameof(FindNeighbors)} is invalid.",
reply
);
}
return(neighbors.Found);
}
catch (InvalidTimestampException)
{
_logger.Debug($"Reply of {nameof(GetNeighbors)}'s timestamp is stale.");
return(ImmutableArray <BoundPeer> .Empty);
}
catch (TimeoutException)
{
RemovePeer(addressee);
return(ImmutableArray <BoundPeer> .Empty);
}
}
