Krzysztof Kwiatkowski aea977d6ea epoll init		pirms 10 gadiem
..
etc	epoll init	pirms 10 gadiem
Makefile	epoll init	pirms 10 gadiem
README.md	epoll init	pirms 10 gadiem
client.cpp	epoll init	pirms 10 gadiem
client.h	epoll init	pirms 10 gadiem
defs.h	epoll init	pirms 10 gadiem
out	epoll init	pirms 10 gadiem
server.cpp	epoll init	pirms 10 gadiem
server.h	epoll init	pirms 10 gadiem
ssl_process.cpp	epoll init	pirms 10 gadiem
ssl_process.h	epoll init	pirms 10 gadiem

README.md

buggy_openssl_with_fullduplex

Toy code which shows problems with non-blocking, fullduplex I/O & renegotiation in OpenSSL

How it works:

Client & Server:
- it has two threads - sender & receiver
- writes and reads are mutexed

Client:
- I/O is blocking (but can be non-blocking)

Server:
- I/O is non-blocking
- each thread runs it's own select()

1. After client & server are connected (and SSL handshake done) client sender
thread starts sending first message (in a loop).

2. When server receives first query it starts sending string EXCHANGE_STRING for
SEND_ITERATIONS number of times. So now we have 4 threads that are sending
and receiving traffic at the same time ( 2 send/receive threads on each
server and client side )

3. When client receives RENEG_INIT_LEN number of characters it starts
renegotiation ( if other one is not pending ). Bug starts to occure here

BUG:
Client side: client starts to report SSL_ERROR_SYSCALL
Server side: server reports SSL_ERROR_WANT_READ when receive function is called

TCP:
In TCP exchange we can see that transfer between client & server is OK until
client sends "Client Hello" packet. This packet is sent when SSL_renegotiate
is called