ianbarber / tlszmq Goto Github PK

Firstly, I have to say that your code really do me a big favour during my recent work. Thanks a lot.

I got a little problem trying to understand some specific sentences in your project----- "socket->send( *request, ZMQ_SNDMORE );", In read_message(...) of the file tlsserver.cpp. In my opinion, the content of "request" is the sender identity(according to the comments), why we have to send it back to the sender? Does it associate with the ssl handshake ?

May be I take it in a wrong way, hope that you can give me some tips to help me understand it right.

Thanks for your time.

Is there a particular rational behind writing the code as a "third party helper" ... not sure what the best term is actually ... instead of transparently wrapping the socket?

From a quick look over the code it seems as though it could be modified easily enough to not require the manual pass in/pass out mechanics, but rather give it the socket and let the tls class do the reading/writing to zmq.
Doing it as a wrapper does lose some flexibility in packet format, but not too much... you'd either have to build the envelope as (ID,Null,Encrypted payload) or prepend/append the payload like (ID, Null, [[arbitary, Null], ...], Encrypted payload). Essentially sacrificing flexibility for code reduction.

As I'm following the code, the input is wrapped in zmq message objects, but it's actually processing it on the basis of a binary stream... that would need to be adjusted for more complicated multipart messages?
I'm not seeing anything to handle message delimiting either ... is it a safe assumption that this code is intended for emulating a stream rather than datagram series, with all the messages being concated together and splitting being purely based on how much of the message has been decoded when you ask if it has data?

What's your thoughts on using an inproc transport for passing data in and out of the tls code?
Something like creating the desired type of ZMQ socket and throwing it off in to a worker thread, then talking to the worker over inproc... the worker takes packets in, strips the envelope, encrypts/decrypts the payload, puts the envelope back on, then passes it off to the socket on other side. Success would likely vary with socket type, ROUTER and PUB/SUB should work well, REQ/REP and PUSH/PULL might not be so good.

Ian - Great work and blog post on on this example - I found it very helpful. I couldn't seem to find a license for the usage of this code. Does one exist? Or would you mind adding a license for the use of tlszmq code or for creating derived works?