[Plugin] Socket.io Client

[getnamo]

@Ironbelly

We’re running into some issues here as well that I was wondering if anyone could shed some light on. The websocket connection is dying in UE right after application data, we get through hellos, cert, and key exchange, then we send data and it sends an encrypted alert that appears to be a close message (warning severity doesn’t have a 0, 1, or 255 - but I suppose this could also be corrupted data?)

Node can connect to the service just fine. First, I noticed they were using different TLS versions so I changed the UE stuff to use 1.2 like node does.

Now I’m looking at traffic and I see they are using different ciphers - node uses TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (0xc02f) and works, but UE is using TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 (0xcca9) even though it lists the first one in its client hello as well as the second. It’s not giving me a legit mismatch message or anything (unless the data in the alert message is corrupted and I just can’t read it) after the encrypted alert, it’s one more app data followed by ACK, FIN/ACK, and RST

The current socket.io plugin doesn’t support https/ssl yet, there is an open issue here: https://github.com//socketio-client-ue4/issues/39 which is on the docket but not yet fixed. Largely all that is missing is to include openssl as a third party lib (which the engine has https://github.com/EpicGames/UnrealEngine/tree/release/Engine/Source/ThirdParty/OpenSSL) and probably change a few lines on how the underlying socket.io-cpp lib is instantiated for https addresses.