How to send messages as websocket client in c++ to a server? - c++

Question

I've a little problem in sendine my messages to the server.
It probably send them and the server recieve them, but i have no real idea how to mask them correctly.
I know this is actually the way:
https://www.rfc-editor.org/rfc/rfc6455#section-5.2
But I'm not understanding a lot of it.
It would be nice if someone could share a whole pseudocode what actually need to be done from the plain message until the writing into the buffer.
I also searched here a lot for information but mostly they advice libs or directly the link. The problem is that libs are nice, but i've actually done already all i need. Only the sending mask is missing.
Regards

Answer 1

Can you send the message with mask bit off?
When mask bit is set, the server expect 4 bytes mask to present, and the payload is XOR'd with
for ( size_t i=0; i<packet_len; i++ ) {
packet[i] = payload[i] ^ mask_bits[i&3];
}
EDIT: Adding more detail.
I assume you have done the Upgrade handshake, the actual bytes to send to network for communication are:
[flag][mask_bit, len][extended length][mask][payload]
Where:
flag: one byte, read the manual, note that I have not tried fragment.
mask bit, one bit located at highest bit of second byte.
len: 7 bits of second byte. If len is 126, real len is 16 bit field of extended length. if it is 127, extended length is 64-bit.
mask: present only if mask bit is set, it's 4 bytes using to XOR the payload.
payload: actual bytes to send
For example, to send "Hello" to server in binary mode, you do:
flag: 0x82, "Final packet in frame" and "Binary mode"
mask bit: 1
len: 6
mask: 0x11, 0x22, 0x33, 0x44
payload: "Hello", 0x48, 0x65, 0x6C, 0x6C, 0x6F, 0x00
The masked payload is: 0x48^0x11, 0x65^0x22, 0x6C^0x33, 0x6C^0x44, 0x6F^0x11, 0x00^0x22
=> 0x59, 0x47, 0x5F, 0x28, 0x7E, 0x22
The whole stream is: 0x82, 0x86, 0x11, 0x22, 0x33, 0x44, 0x59, 0x47, 0x5F, 0x28, 0x7E, 0x22