fix(remoteingress-core): send PROXY v2 headers for UDP upstream sessions and expire idle UDP sessions

test/test.udp.node.ts

@@ -29,15 +29,16 @@ async function findFreePorts(count: number): Promise<number[]> {
 function startUdpEchoServer(port: number, host: string): Promise<dgram.Socket> {
   return new Promise((resolve, reject) => {
     const server = dgram.createSocket('udp4');
-    let proxyHeaderReceived = false;
+    // Track which source endpoints have sent their PROXY v2 header.
+    // The hub sends a 28-byte PROXY v2 header as the first datagram per session.
+    const seenSources = new Set<string>();
 
     server.on('message', (msg, rinfo) => {
-      if (!proxyHeaderReceived) {
-        // First datagram is the PROXY v2 header (28 bytes for IPv4)
-        // In the current implementation, the hub connects directly via UDP
-        // so the first real datagram is the actual data (no PROXY header yet)
-        // For now, just echo everything back
-        proxyHeaderReceived = true;
+      const sourceKey = `${rinfo.address}:${rinfo.port}`;
+      if (!seenSources.has(sourceKey)) {
+        seenSources.add(sourceKey);
+        // First datagram from this source is the PROXY v2 header — skip it
+        return;
       }
       // Echo back
       server.send(msg, rinfo.port, rinfo.address);