curl: WebSocket Logic Error: Control Frame (PING/PONG) Starvation causes Connection Drop (DoS) during large transfers

Summary: I have discovered a logic flaw in lib/ws.c regarding the handling of WebSocket Control Frames PING/PONG. According to RFC 6455, Control Frames should be processed as soon as possible, even in the middle of fragmented data frames, to maintain connection state Keep-Alive. However, libcurl...