63 lines
2.2 KiB
Markdown
63 lines
2.2 KiB
Markdown
# WebSocket Keep-Alive Fix for SNI Passthrough
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## Problem
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WebSocket connections in SNI passthrough mode are being disconnected every 30 seconds due to:
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1. **WebSocket Heartbeat**: The HTTP proxy's WebSocket handler performs heartbeat checks every 30 seconds using ping/pong frames. In SNI passthrough mode, these frames can't be injected into the encrypted stream, causing connections to be marked as inactive and terminated.
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2. **Half-Zombie Detection**: The connection manager's aggressive cleanup gives only 30 seconds grace period for connections where one socket is destroyed.
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## Solution
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For SNI passthrough connections:
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1. Disable WebSocket-specific heartbeat checking (they're handled as raw TCP)
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2. Rely on TCP keepalive settings instead
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3. Increase grace period for encrypted connections
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## Current Settings
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- Default inactivity timeout: 4 hours (14400000 ms)
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- Keep-alive multiplier for extended mode: 6x (24 hours)
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- WebSocket heartbeat interval: 30 seconds (problem!)
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- Half-zombie grace period: 30 seconds (too aggressive)
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## Recommended Configuration
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```typescript
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const proxy = new SmartProxy({
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// Increase grace period for connection cleanup
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inactivityTimeout: 14400000, // 4 hours default
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keepAliveTreatment: 'extended', // or 'immortal' for no timeout
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keepAliveInactivityMultiplier: 10, // 40 hours for keepalive connections
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// For routes with WebSocket over SNI passthrough
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routes: [
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{
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name: 'websocket-passthrough',
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match: { ports: 443, domains: 'ws.example.com' },
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action: {
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type: 'forward',
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target: { host: 'backend', port: 443 },
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tls: { mode: 'passthrough' },
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// No WebSocket-specific config needed for passthrough
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}
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}
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]
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});
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```
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## Temporary Workaround
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Until a fix is implemented, you can:
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1. Use `keepAliveTreatment: 'immortal'` to disable timeout-based cleanup
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2. Increase the half-zombie grace period
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3. Use TCP keepalive at the OS level
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## Proper Fix Implementation
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1. Detect when a connection is SNI passthrough
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2. Skip WebSocket heartbeat for passthrough connections
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3. Increase grace period for encrypted connections
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4. Rely on TCP keepalive instead of application-level ping/pong |