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Bump to v1.6.0: peer-address recovery, reconnect crash, long-run memory/CPU leak

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Three reliability fixes. Wire format and audio pipeline unchanged from
v1.4 / v1.5 — all interoperate.

Peer address recovery:
* When a tracked peer goes Unreachable (its resolved address — often a
  stale DNS / Pi-hole record, or a peer that rebooted onto a new IP) but
  the same peer is still heartbeat-pinging us from a different address,
  RemSound now adopts the live address instead of transmitting to a dead
  one. HeartbeatService records untracked ping sources; MainForm's
  TryAdoptLiveHeartbeatAddress (1 Hz) re-points the sender, heartbeat
  tracking and receiver allow-list. Conservative: fires only on the
  unambiguous one-unreachable-and-one-source case, private-range (RFC1918)
  addresses only so a relay can't hijack the sender, 10 s cooldown.

Reconnect crash:
* Fixed IndexOutOfRangeException in MainForm.SyncConnectedList. A churny
  peer-list rebuild (peer reboot) left SelectedIndex pointing past the
  rebuilt item array; the 1 Hz status timer read SelectedItem and crashed
  the app. New SafeSelectedItem bounds-checks the index; applied to all
  three timer-driven sync methods. The status tick is also wrapped in
  try/catch so a transient WinForms hiccup logs instead of crashing.

Long-run memory / CPU leak:
* A receiver left running for hours grew to gigabytes and climbing CPU.
  Decoder sessions orphaned by peer reconnects were not reaped — every
  reconnect mints a fresh (endpoint, streamId) key, and PruneIdleSessions
  silently skipped sessions whose PlayoutEngine lookup missed. Rewrote it
  to reap on each session's own LastWriteUtc (no cross-dictionary lookup),
  added a hard MaxLiveSessions cap as a backstop, and a "stream sessions
  live: N" diagnostic line. Bounds both memory and render-thread CPU.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
Ednunp
2026-05-18 21:32:22 +01:00
co-authored by Claude Opus 4.7
parent 9ceff8bcc1
commit 918ca6cac0
8 changed files with 232 additions and 47 deletions
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src/RemSound.Receiver/AudioReceiver.cs
+51 -15
View File
@@ -44,6 +44,14 @@ public sealed class AudioReceiver : IDisposable
/// though the mix output is unaffected).</summary>
public static readonly TimeSpan SessionIdleTimeout = TimeSpan.FromSeconds(4);
/// <summary>Hard ceiling on concurrently-tracked stream sessions. A backstop for the idle
/// prune: even if reconnect churn somehow outpaces the idle sweep, the session table — and
/// the multi-MB playout ring each entry owns — can never grow without bound. Far above any
/// legitimate scenario (the lobby relay caps peers at 10, and a peer emits at most one
/// stream per render lane). When exceeded, <see cref="PruneIdleSessions"/> evicts the
/// idlest sessions down to this cap. 2026-05-15.</summary>
public const int MaxLiveSessions = 32;
private readonly Stopwatch uptime = new();
private readonly ReceiverDiagnostics diagnostics = new();
private readonly PlayoutEngine playoutEngine;
@@ -57,6 +65,10 @@ public sealed class AudioReceiver : IDisposable
// independent audio mode). For single-lane modes the sender emits one streamId so
// the dict still has one entry per peer, identical to the pre-refactor behaviour.
private readonly Dictionary<(IPEndPoint Endpoint, ushort StreamId), StreamSession> sessions = new();
// Last live-session count emitted to the diagnostic sink. Lets PruneIdleSessions log
// only when the count actually changes, so unbounded growth is visible in the log
// without spamming it or needing a Task Manager screenshot to notice.
private int lastLoggedSessionCount = -1;
/// <summary>When false (the default), a Format packet arriving with a NEW streamId from
/// a peer that already has a session under a DIFFERENT streamId triggers immediate
@@ -591,30 +603,54 @@ public sealed class AudioReceiver : IDisposable
public void PruneIdleSessions()
{
var now = DateTime.UtcNow;
List<(IPEndPoint Endpoint, ushort StreamId)>? toRemove = null;
lock (sessionsLock)
{
var toRemove = new HashSet<(IPEndPoint Endpoint, ushort StreamId)>();
// 1) Idle sweep — reap sessions with no decoded write within SessionIdleTimeout.
// Reaped on the session's OWN last-write time. The previous implementation
// cross-referenced PlayoutEngine.ActiveSessions by (endpoint, streamId) and
// silently skipped — leaking the session forever — whenever that lookup missed.
// A reconnecting peer never reuses an old key: a sender reboot rerolls the
// streamId AND rebinds to a fresh ephemeral source port, so the old session is
// always an orphan the lookup-based prune could strand. Reading the session's
// own LastWriteUtc removes the lookup, the race, and the leak. 2026-05-15.
foreach (var (key, session) in sessions)
{
// Match SessionPlayout by full key so two streams from the same peer don't
// share a single SessionPlayout entry. ActiveSessions iteration is small
// (one per active stream).
var sp = playoutEngine.ActiveSessions.FirstOrDefault(x =>
x.Endpoint.Equals(key.Endpoint) && x.StreamId == key.StreamId);
if (sp is null) continue;
if (now - sp.LastWriteUtc <= SessionIdleTimeout) continue;
toRemove ??= [];
toRemove.Add(key);
if (now - session.LastWriteUtc > SessionIdleTimeout) toRemove.Add(key);
}
if (toRemove is not null)
// 2) Hard-cap backstop. If more than MaxLiveSessions would still remain after the
// idle sweep, evict the idlest extras. Guarantees the session table can never
// grow without bound whatever churn the idle sweep can't keep up with.
var survivors = sessions.Count - toRemove.Count;
if (survivors > MaxLiveSessions)
{
foreach (var key in toRemove)
foreach (var key in sessions
.Where(kv => !toRemove.Contains(kv.Key))
.OrderBy(kv => kv.Value.LastWriteUtc)
.Take(survivors - MaxLiveSessions)
.Select(kv => kv.Key))
{
if (sessions.Remove(key, out var session)) session.Dispose();
playoutEngine.RemoveSession(key.Endpoint, key.StreamId);
diagnosticSink?.Invoke($"stream session pruned (idle): {key.Endpoint} stream={key.StreamId}");
toRemove.Add(key);
}
}
// 3) Apply removals — drop the StreamSession and its paired SessionPlayout together.
foreach (var key in toRemove)
{
if (sessions.Remove(key, out var session)) session.Dispose();
playoutEngine.RemoveSession(key.Endpoint, key.StreamId);
diagnosticSink?.Invoke($"stream session pruned: {key.Endpoint} stream={key.StreamId}");
}
// Surface the live-session count whenever it changes, so any accumulation is
// visible in the log without summing open/prune events.
if (sessions.Count != lastLoggedSessionCount)
{
lastLoggedSessionCount = sessions.Count;
diagnosticSink?.Invoke($"stream sessions live: {sessions.Count}");
}
}
}