Adds description

README.md

@@ -2,3 +2,37 @@ 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

client.cpp

@@ -45,9 +45,11 @@ bool handle_error_code(int& len, SSL* SSLHandler, int code, const char* func)
         break;
     case SSL_ERROR_WANT_READ:
         cout << func << " WANT READ" << endl;
+        return true;
         break;
     case SSL_ERROR_WANT_WRITE:
         cout << func << " WANT WRITE" << endl;
+        return true;
         break;
     case SSL_ERROR_SYSCALL:
         cout << func << " ESYSCALL" << endl;
@@ -55,10 +57,12 @@ bool handle_error_code(int& len, SSL* SSLHandler, int code, const char* func)
         break;
     case SSL_ERROR_SSL:
         cout << func << " ESSL" << endl;
+        return true;
         exit(1);
         break;
     default:
         cout << func << " SOMETHING ELSE" << endl;
+        return true;
         exit(1);
 
     }
@@ -75,9 +79,7 @@ void Sender()
         int len = 0;
         do
         {
-            bool flag = true;
+            while( 1 )
-
-            while( flag )
             {
                 lock_guard<mutex> lock(WriteReadMutex);
                 cout << "SSL_write: start" << endl;