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Auto-rebuild listener on fatal socket errors and refactor listener creation #44

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97 changes: 82 additions & 15 deletions cadente/Sisk.Cadente/HttpHost.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,14 +21,15 @@ namespace Sisk.Cadente;
public sealed class HttpHost : IDisposable {

private readonly IPEndPoint _endpoint;
private readonly Socket _listener;
private Socket _listener;

// cache line padding to reduce false sharing
private volatile bool _disposedValue;
private volatile bool _isListening;

private readonly SocketAsyncEventArgs [] _acceptArgsPool;
private readonly int [] _acceptArgsAvailable;
private int _listenerRestarting = 0;
private const int AcceptPoolSize = 8;
private const int ListenerAcceptRetryDelayMilliseconds = 250;

Expand Down Expand Up @@ -69,7 +70,7 @@ public sealed class HttpHost : IDisposable {
/// <param name="endpoint">The <see cref="IPEndPoint"/> to listen on.</param>
public HttpHost ( IPEndPoint endpoint ) {
_endpoint = endpoint;
_listener = new Socket ( endpoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp );
_listener = CreateListenerSocket ();

_acceptArgsPool = new SocketAsyncEventArgs [ AcceptPoolSize ];
_acceptArgsAvailable = new int [ AcceptPoolSize ];
Expand Down Expand Up @@ -97,7 +98,12 @@ public void Start () {
return;
ObjectDisposedException.ThrowIf ( _disposedValue, this );

ConfigureListenerSocket ();
try {
_listener.Dispose ();
}
catch { }

_listener = CreateListenerSocket ();
_listener.Bind ( _endpoint );
_listener.Listen ( backlog: 4096 ); // Alto para burst de conexões
_isListening = true;
Expand All @@ -109,30 +115,37 @@ public void Start () {
}

[MethodImpl ( MethodImplOptions.AggressiveInlining )]
private void ConfigureListenerSocket () {
_listener.NoDelay = true;
_listener.LingerState = new LingerOption ( false, 0 );
private Socket CreateListenerSocket () {
var listener = new Socket ( _endpoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp );

listener.NoDelay = true;
listener.LingerState = new LingerOption ( false, 0 );

// Buffers grandes para o listener reduzem syscalls
_listener.ReceiveBufferSize = 128 * 1024;
_listener.SendBufferSize = 128 * 1024;
listener.ReceiveBufferSize = 128 * 1024;
listener.SendBufferSize = 128 * 1024;

if (_listener.AddressFamily == AddressFamily.InterNetworkV6 && _endpoint.Address.Equals ( IPAddress.IPv6Any )) {
_listener.DualMode = true;
if (listener.AddressFamily == AddressFamily.InterNetworkV6 && _endpoint.Address.Equals ( IPAddress.IPv6Any )) {
listener.DualMode = true;
}

_listener.SetSocketOption ( SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true );
_listener.SetSocketOption ( SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true );
_listener.SetSocketOption ( SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveInterval, 3 );
_listener.SetSocketOption ( SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveTime, 300 );
_listener.SetSocketOption ( SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveRetryCount, 3 );
listener.SetSocketOption ( SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true );
listener.SetSocketOption ( SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true );
listener.SetSocketOption ( SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveInterval, 3 );
listener.SetSocketOption ( SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveTime, 300 );
listener.SetSocketOption ( SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveRetryCount, 3 );

return listener;
}

[MethodImpl ( MethodImplOptions.AggressiveInlining )]
private void StartAccept ( int poolIndex ) {
if (!_isListening)
return;

if (Volatile.Read ( ref _listenerRestarting ) == 1)
return;

while (_isListening) {
var args = _acceptArgsPool [ poolIndex ];
args.AcceptSocket = null;
Expand All @@ -145,11 +158,17 @@ private void StartAccept ( int poolIndex ) {
return;
}
catch (SocketException) {
if (Volatile.Read ( ref _listenerRestarting ) == 1)
return;

QueueStartAccept ( poolIndex, ListenerAcceptRetryDelayMilliseconds );
return;
}

int rearmDelayMs = ProcessAcceptInline ( args, poolIndex );
if (rearmDelayMs < 0)
return;

if (rearmDelayMs > 0) {
QueueStartAccept ( poolIndex, rearmDelayMs );
return;
Expand All @@ -160,6 +179,9 @@ private void StartAccept ( int poolIndex ) {
private void OnAcceptCompleted ( object? sender, SocketAsyncEventArgs e ) {
int poolIndex = (int) e.UserToken!;
int rearmDelayMs = ProcessAcceptInline ( e, poolIndex );
if (rearmDelayMs < 0)
return;

if (rearmDelayMs > 0)
QueueStartAccept ( poolIndex, rearmDelayMs );
else
Expand All @@ -173,6 +195,11 @@ private int ProcessAcceptInline ( SocketAsyncEventArgs e, int poolIndex ) {
e.AcceptSocket?.Dispose ();
e.AcceptSocket = null;

if (IsListenerFatalError ( socketError )) {
TriggerListenerRebuild ();
return -1;
}

return IsConnectionAcceptNoise ( socketError )
? 0
: ListenerAcceptRetryDelayMilliseconds;
Expand Down Expand Up @@ -215,6 +242,46 @@ or SocketError.ConnectionReset
or SocketError.ConnectionAborted
or SocketError.NetworkReset;

private static bool IsListenerFatalError ( SocketError socketError ) =>
socketError is SocketError.InvalidArgument
or SocketError.NotSocket
or SocketError.Shutdown
or SocketError.OperationAborted
or SocketError.Interrupted;

private void TriggerListenerRebuild () {
if (Interlocked.CompareExchange ( ref _listenerRestarting, 1, 0 ) != 0)
return;

_ = RebuildListenerAsync ();
}

private async Task RebuildListenerAsync () {
try { _listener.Close (); } catch { }
try { _listener.Dispose (); } catch { }

while (_isListening && !_disposedValue) {
await Task.Delay ( ListenerAcceptRetryDelayMilliseconds ).ConfigureAwait ( false );

try {
Socket newListener = CreateListenerSocket ();
newListener.Bind ( _endpoint );
newListener.Listen ( backlog: 4096 );
_listener = newListener;
break;
}
catch (SocketException) {
}
Comment on lines +273 to +274
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@chatgpt-codex-connector chatgpt-codex-connector Bot May 26, 2026

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P1 Badge Dispose failed rebuilt listener before retry loop

When CreateListenerSocket()/Bind/Listen throws during RebuildListenerAsync, the catch (SocketException) block swallows the exception and immediately retries without disposing the just-created newListener. In a persistent failure (e.g., endpoint temporarily unavailable), this leaks one socket handle every 250ms, which can exhaust file descriptors and prevent the host from recovering.

Useful? React with 👍 / 👎.

}

Interlocked.Exchange ( ref _listenerRestarting, 0 );

if (_isListening && !_disposedValue) {
for (int i = 0; i < AcceptPoolSize; i++)
StartAccept ( i );
}
}

[MethodImpl ( MethodImplOptions.AggressiveOptimization )]
internal async Task ProcessConnectionCoreAsync ( Socket client ) {
// Early exit se não há handler
Expand Down
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