0.3.82: relax TCP keepalive timings (Wi-Fi-friendly)

CHANGELOG.md

@@ -2,6 +2,32 @@
 
 > **Note:** Versions 0.3.24 – 0.3.54 were released as git tags without changelog entries. Changelog resumes at 0.3.55 below.
 
+## 0.3.82
+
+### Fixed
+
+- **Relaxed TCP keepalive timings.** v0.3.81 set `keepaliveIdle = 1`,
+  `keepaliveInterval = 1`, `keepaliveCount = 3` — ~4 seconds to declare a
+  socket dead. That was far too aggressive for real-world Wi-Fi: brief
+  mid-handshake pauses on healthy connections triggered keepalive reaping
+  before the application-level handshake exchange could complete, producing
+  `[SYM] session: handshake timeout after 10s — disconnecting` even on
+  fully-functional peers.
+
+  v0.3.82 relaxes to `keepaliveIdle = 10`, `keepaliveInterval = 30`,
+  `keepaliveCount = 3` → ~100s to declare dead. Wi-Fi blips of a few
+  seconds during handshake exchange or active CMB flow no longer trigger
+  reaping; peer-restart scenarios still recover within ~100s instead of
+  the macOS default ~2h.
+
+  Application-layer `lastSeen`-stale check in `SymNode.addPeer` from
+  v0.3.81 still handles faster recovery: a peer entry older than 10s
+  is treated as stale and the new dial replaces it, regardless of
+  whether OS keepalive has reaped the underlying socket yet. So the
+  effective recovery time for the user-visible "peer restarted, can
+  re-connect now" case is still ~10s, while OS-level keepalive is the
+  fallback for cases the application layer doesn't see.
+
 ## 0.3.81
 
 ### Fixed

Sources/SYM/SymPeerSession.swift

@@ -89,26 +89,36 @@ final class SymPeerSession {
 
     // MARK: - Init
 
-    /// TCP parameters with aggressive keepalive. Default macOS TCP keepalive
-    /// is `TCP_KEEPALIVE = 7200s` (2 hours) before the first probe, which
-    /// means a dead-but-ESTABLISHED socket (peer process killed without
+    /// TCP parameters with Wi-Fi-friendly keepalive. Default macOS TCP
+    /// keepalive is `TCP_KEEPALIVE = 7200s` (2 hours) before the first probe,
+    /// which means a dead-but-ESTABLISHED socket (peer process killed without
     /// graceful FIN — common on iOS app suspension and Mac Catalyst rebuilds)
     /// stays in ESTABLISHED state on the survivor side for hours. The
     /// addPeer dedup logic then keeps rejecting the live new dial against
     /// this zombie entry.
     ///
-    /// Settings here mirror @sym-bot/sym v0.5.3 on the Node side:
-    /// 1s initial idle, 1s probe interval, 3 probes before decl-dead → dead
-    /// sockets reaped in ~4 seconds instead of ~2 hours. Same fix shape
-    /// applied to both sides of the dual-runtime mesh so cross-runtime
-    /// peers (sym-swift ↔ sym-node) recover symmetrically from peer
-    /// restarts.
+    /// Earlier v0.3.81 tried `idle=1s, interval=1s, count=3` (~4s detection)
+    /// to mirror @sym-bot/sym v0.5.3's `setKeepAlive(true, 1000)`. That was
+    /// far too aggressive for Wi-Fi: handshake-in-progress connections that
+    /// had brief mid-exchange pauses got reaped before the protocol-level
+    /// handshake exchange could complete, producing
+    /// "[SYM] session: handshake timeout after 10s — disconnecting" on
+    /// healthy connections.
+    ///
+    /// v0.3.82 relaxes to `idle=10s, interval=30s, count=3` → ~100s to
+    /// declare dead. Wi-Fi blips of a few seconds don't trigger reaping;
+    /// peer-restart scenarios still recover within ~100s instead of ~2h.
+    /// The application-layer `lastSeen`-stale check in `SymNode.addPeer`
+    /// (also shipped in v0.3.81) handles faster recovery: a peer entry
+    /// older than 10s is treated as stale and the new dial replaces it,
+    /// regardless of whether OS keepalive has reaped the underlying
+    /// socket yet.
     static func tcpParametersWithKeepalive() -> NWParameters {
         let params = NWParameters.tcp
         if let tcp = params.defaultProtocolStack.transportProtocol as? NWProtocolTCP.Options {
             tcp.enableKeepalive = true
-            tcp.keepaliveIdle = 1
-            tcp.keepaliveInterval = 1
+            tcp.keepaliveIdle = 10
+            tcp.keepaliveInterval = 30
             tcp.keepaliveCount = 3
         }
         return params