When server restarts, new ETCP_CONN has session_id=0 (calloc).
If client sends INIT_REQUEST_NOINIT (0x04) with session_id=0,
the condition conn->session_id != session_id is false (both 0),
so no reset was sent. Client kept old seq numbers while server
expected seq=1, causing 'Waiting for initial packet' deadlock.
Fix: add || new_conn to the condition — when server created a
fresh connection (was restarted), always send reset to client.