Add SSH keepalive and TCP keepalive to prevent silent disconnects

- SSH keepalive every 30s (configurable via SSH_KEEPALIVE_INTERVAL)
- TCP keepalive on client sockets
- Increase pre-auth timeout from 30s to 300s
- Log keepalive settings on startup

proxy.py

@@ -17,6 +17,10 @@ TS6_SSH_PORT = int(os.environ.get("TS6_SSH_PORT", "10022"))
 LISTEN_HOST = "0.0.0.0"
 LISTEN_PORT = int(os.environ.get("LISTEN_PORT", "10011"))
 
+# Keepalive settings
+SSH_KEEPALIVE_INTERVAL = int(os.environ.get("SSH_KEEPALIVE_INTERVAL", "30"))
+SSH_KEEPALIVE_COUNT_MAX = int(os.environ.get("SSH_KEEPALIVE_COUNT_MAX", "3"))
+
 TS3_BANNER = (
     b"TS3\n\r"
     b"Welcome to the TeamSpeak 3 ServerQuery interface, "
@@ -36,6 +40,12 @@ class ClientHandler:
     async def handle(self) -> None:
         log.info("Client connected from %s", self.addr)
         try:
+            # Enable TCP keepalive on the client socket
+            sock = self.writer.get_extra_info("socket")
+            if sock:
+                import socket
+                sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
+
             self.writer.write(TS3_BANNER)
             await self.writer.drain()
             await self._auth_loop()
@@ -50,7 +60,7 @@ class ClientHandler:
 
     async def _auth_loop(self) -> None:
         while True:
-            line = await asyncio.wait_for(self.reader.readline(), timeout=30)
+            line = await asyncio.wait_for(self.reader.readline(), timeout=300)
             if not line:
                 return
             cmd = line.decode("utf-8", errors="replace").strip()
@@ -98,6 +108,8 @@ class ClientHandler:
                     username=username,
                     password=password,
                     known_hosts=None,
+                    keepalive_interval=SSH_KEEPALIVE_INTERVAL,
+                    keepalive_count_max=SSH_KEEPALIVE_COUNT_MAX,
                 ),
                 timeout=10,
             )
@@ -118,7 +130,7 @@ class ClientHandler:
                 except asyncio.TimeoutError:
                     break
 
-            log.info("SSH session established for %s", self.addr)
+            log.info("SSH session established for %s (keepalive=%ds)", self.addr, SSH_KEEPALIVE_INTERVAL)
             return True
         except asyncssh.PermissionDenied:
             log.warning("SSH auth failed for %s (bad credentials)", self.addr)
@@ -161,7 +173,6 @@ class ClientHandler:
         done, pending = await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
         for t in pending:
             t.cancel()
-        # Await cancelled tasks to suppress warnings
         for t in pending:
             try:
                 await t
@@ -201,6 +212,7 @@ async def main() -> None:
     server = await asyncio.start_server(handle_client, LISTEN_HOST, LISTEN_PORT)
     log.info("TS3 Query Proxy listening on %s:%d", LISTEN_HOST, LISTEN_PORT)
     log.info("Forwarding to %s:%d (SSH Query)", TS6_HOST, TS6_SSH_PORT)
+    log.info("SSH keepalive: interval=%ds, max_count=%d", SSH_KEEPALIVE_INTERVAL, SSH_KEEPALIVE_COUNT_MAX)
     async with server:
         await server.serve_forever()