// This updates routing table when receiving a message.
// if corresponding bucket for remote peer is not full, just adds remote peer.
// otherwise check whether if the least recently used (LRU) peer
// is alive to determine evict LRU peer or discard remote peer.
private async Task UpdateAsync(
Peer rawPeer,
CancellationToken cancellationToken = default(CancellationToken))
{
if (rawPeer is null)
{
throw new ArgumentNullException(nameof(rawPeer));
}
if (!(rawPeer is BoundPeer peer) || rawPeer.AppProtocolVersion != _appProtocolVersion)
{
// Don't update peer without endpoint or with different appProtocolVersion.
return;
}
if (cancellationToken.IsCancellationRequested)
{
throw new TaskCanceledException();
}
bool contains = _routing.Contains(peer);
BoundPeer evictionCandidate = await _routing.AddPeerAsync(peer);
if (evictionCandidate is null)
{
// added successfully since there was empty space in the bucket
if (!contains)
{
_routing.BucketOf(peer).ReplacementCache.Remove(peer);
_logger.Debug($"Added [{peer.Address.ToHex()}] to table");
}
}
else
{
_logger.Verbose(
"Need to evict {Candidate}; trying...",
evictionCandidate);
try
{
if (!_routing.BucketOf(peer).ReplacementCache.Contains(peer))
{
_routing.BucketOf(peer).ReplacementCache.Add(peer);
}
await PingAsync(
evictionCandidate,
_requestTimeout,
cancellationToken);
}
catch (TimeoutException)
{
await RemovePeerAsync(evictionCandidate);
_logger.Verbose(
"Peer ({Candidate}) has been evicted.",
evictionCandidate);
}
}
}
/// <summary>
/// Process <see cref="Peer"/>s that is replied by sending <see cref="FindNeighbors"/>
/// request.
/// </summary>
/// <param name="found"><see cref="Peer"/>s that found.</param>
/// <param name="target">The target <see cref="Address"/> to search.</param>
/// <param name="depth">Target depth of recursive operation. If -1 is given,
/// it runs until the closest peer is found.</param>
/// <param name="timeout"><see cref="TimeSpan"/> for next depth's
/// <see cref="FindPeerAsync"/> operation.</param>
/// <param name="cancellationToken">A cancellation token used to propagate notification
/// that this operation should be canceled.</param>
/// <returns>An awaitable task without value.</returns>
/// <exception cref="TimeoutException">Thrown when all peers that found are
/// not online.</exception>
private async Task ProcessFoundAsync(
ImmutableList <BoundPeer> found,
Address target,
int depth,
TimeSpan?timeout,
CancellationToken cancellationToken)
{
List <BoundPeer> peers = found.Where(
peer => !peer.Address.Equals(_address) && !_routing.Contains(peer)).ToList();
if (peers.Count == 0)
{
_logger.Debug("No any neighbor received.");
return;
}
peers = Kademlia.SortByDistance(peers, target);
List <BoundPeer> closestCandidate = _routing.Neighbors(target, _bucketSize).ToList();
Task[] awaitables = peers.Select(peer =>
PingAsync(peer, _requestTimeout, cancellationToken)
).ToArray();
try
{
await Task.WhenAll(awaitables);
}
catch (AggregateException e)
{
if (e.InnerExceptions.All(ie => ie is TimeoutException) &&
e.InnerExceptions.Count == awaitables.Length)
{
throw new TimeoutException(
$"All neighbors found do not respond in {_requestTimeout}."
);
}
_logger.Error(
e,
"Some responses from neighbors found unexpectedly terminated: {Exception}",
e
);
}
var findNeighboursTasks = new List <Task>();
Peer closestKnown = closestCandidate.Count == 0 ? null : closestCandidate[0];
for (int i = 0; i < Kademlia.FindConcurrency && i < peers.Count; i++)
{
if (closestKnown is null ||
string.CompareOrdinal(
Kademlia.CalculateDistance(peers[i].Address, target).ToHex(),
Kademlia.CalculateDistance(closestKnown.Address, target).ToHex()
) < 1)
{
findNeighboursTasks.Add(FindPeerAsync(
target,
peers[i],
(depth == -1) ? depth : depth + 1,
timeout,
cancellationToken));
}
}
try
{
await Task.WhenAll(findNeighboursTasks);
}
catch (TimeoutException)
{
if (findNeighboursTasks.All(findPeerTask => findPeerTask.IsFaulted))
{
throw new TimeoutException(
"Timeout exception occurred during ProcessFoundAsync().");
}
}
}
/// <summary>
/// Process <see cref="Peer"/>s that is replied by sending <see cref="FindNeighbors"/>
/// request.
/// </summary>
/// <param name="history"><see cref="Peer"/>s that already searched.</param>
/// <param name="dialHistory"><see cref="Peer"/>s that ping sent.</param>
/// <param name="found"><see cref="Peer"/>s that found.</param>
/// <param name="target">The target <see cref="Address"/> to search.</param>
/// <param name="depth">Target depth of recursive operation. If -1 is given,
/// it runs until the closest peer is found.</param>
/// <param name="timeout"><see cref="TimeSpan"/> for next depth's
/// <see cref="FindPeerAsync"/> operation.</param>
/// <param name="cancellationToken">A cancellation token used to propagate notification
/// that this operation should be canceled.</param>
/// <returns>An awaitable task without value.</returns>
/// <exception cref="TimeoutException">Thrown when all peers that found are
/// not online.</exception>
private async Task ProcessFoundAsync(
ConcurrentBag <BoundPeer> history,
ConcurrentBag <BoundPeer> dialHistory,
IEnumerable <BoundPeer> found,
Address target,
int depth,
TimeSpan?timeout,
CancellationToken cancellationToken)
{
List <BoundPeer> peers = found.Where(
peer =>
!peer.Address.Equals(_address) &&
!_table.Contains(peer) &&
!history.Contains(peer)).ToList();
if (peers.Count == 0)
{
_logger.Verbose("No any neighbor received.");
return;
}
peers = Kademlia.SortByDistance(peers, target).ToList();
List <BoundPeer> closestCandidate =
_table.Neighbors(target, _table.BucketSize, false).ToList();
Task[] awaitables = peers
.Where(peer => !dialHistory.Contains(peer))
.Select(
peer =>
{
dialHistory.Add(peer);
return(PingAsync(peer, _requestTimeout, cancellationToken));
}
).ToArray();
try
{
await Task.WhenAll(awaitables);
}
catch (Exception)
{
IEnumerable <AggregateException> exceptions = awaitables
.Where(t => t.IsFaulted)
.Select(t => t.Exception);
foreach (var ae in exceptions)
{
var isTimeout = false;
foreach (var ie in ae.InnerExceptions)
{
if (ie is PingTimeoutException pte)
{
peers.Remove(pte.Target);
isTimeout = true;
break;
}
}
if (isTimeout)
{
break;
}
_logger.Warning(
ae,
"Some responses from neighbors found unexpectedly terminated: {ae}",
ae
);
}
}
var findPeerTasks = new List <Task>();
Peer closestKnown = closestCandidate.FirstOrDefault();
var count = 0;
foreach (var peer in peers)
{
if (!(closestKnown is null) &&
string.CompareOrdinal(
Kademlia.CalculateDistance(peer.Address, target).ToHex(),
Kademlia.CalculateDistance(closestKnown.Address, target).ToHex()
) >= 1)
{
break;
}
if (history.Contains(peer))
{
continue;
}
findPeerTasks.Add(FindPeerAsync(
history,
dialHistory,
target,
peer,
depth == -1 ? depth : depth - 1,
timeout,
cancellationToken));
if (count++ >= _findConcurrency)
{
break;
}
}
try
{
await Task.WhenAll(findPeerTasks);
}
catch (Exception e)
{
_logger.Error(
e,
"Some FindPeer tasks were unexpectedly terminated: {Exception}",
e
);
}
}
/// <summary>
/// Process <see cref="Peer"/>s that is replied by sending <see cref="FindNeighbors"/>
/// request.
/// </summary>
/// <param name="history"><see cref="Peer"/>s that already searched.</param>
/// <param name="found"><see cref="Peer"/>s that found.</param>
/// <param name="target">The target <see cref="Address"/> to search.</param>
/// <param name="depth">Target depth of recursive operation. If -1 is given,
/// it runs until the closest peer is found.</param>
/// <param name="timeout"><see cref="TimeSpan"/> for next depth's
/// <see cref="FindPeerAsync"/> operation.</param>
/// <param name="cancellationToken">A cancellation token used to propagate notification
/// that this operation should be canceled.</param>
/// <returns>An awaitable task without value.</returns>
/// <exception cref="TimeoutException">Thrown when all peers that found are
/// not online.</exception>
private async Task ProcessFoundAsync(
ConcurrentBag <BoundPeer> history,
IEnumerable <BoundPeer> found,
Address target,
int depth,
TimeSpan?timeout,
CancellationToken cancellationToken)
{
List <BoundPeer> peers = found.Where(
peer =>
!peer.Address.Equals(_address) &&
!_routing.Contains(peer) &&
!history.Contains(peer)).ToList();
if (peers.Count == 0)
{
_logger.Debug("No any neighbor received.");
return;
}
peers = Kademlia.SortByDistance(peers, target);
List <BoundPeer> closestCandidate = _routing.Neighbors(target, _bucketSize).ToList();
Task[] awaitables = peers.Select(peer =>
PingAsync(peer, _requestTimeout, cancellationToken)
).ToArray();
try
{
await Task.WhenAll(awaitables);
}
catch (Exception e)
{
_logger.Error(
e,
"Some responses from neighbors found unexpectedly terminated: {Exception}",
e
);
}
var findPeerTasks = new List <Task>();
Peer closestKnown = closestCandidate.Count == 0 ? null : closestCandidate[0];
var count = 0;
foreach (var peer in peers)
{
if (!(closestKnown is null) &&
string.CompareOrdinal(
Kademlia.CalculateDistance(peer.Address, target).ToHex(),
Kademlia.CalculateDistance(closestKnown.Address, target).ToHex()
) >= 1)
{
break;
}
if (history.Contains(peer))
{
continue;
}
findPeerTasks.Add(FindPeerAsync(
history,
target,
peer,
depth == -1 ? depth : depth - 1,
timeout,
cancellationToken));
if (count++ >= Kademlia.FindConcurrency)
{
break;
}
}
try
{
await Task.WhenAll(findPeerTasks);
}
catch (Exception e)
{
_logger.Error(
e,
"Some FindPeer tasks were unexpectedly terminated: {Exception}",
e
);
}
}