New wire format for REQ/REP pattern

This patch introduces two changes:
1. 32-bit ID is used to identify the peer instead of UUID
2. REQ socket seeds the label stack with unique 32-bit request ID
   It also drops any replies with non-matching request ID

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/req.hpp b/src/req.hpp
index e0554ac..50dcb44 100644
--- a/src/req.hpp
+++ b/src/req.hpp
@@ -22,6 +22,7 @@
 #define __ZMQ_REQ_HPP_INCLUDED__
 
 #include "xreq.hpp"
+#include "stdint.hpp"
 
 namespace zmq
 {
@@ -49,6 +50,10 @@ namespace zmq
         //  of the message must be empty message part (backtrace stack bottom).
         bool message_begins;
 
+        //  Request ID. Request numbers gradually increase (and wrap over)
+        //  so that we don't have to generate random ID for each request.
+        uint32_t request_id;
+
         req_t (const req_t&);
         const req_t &operator = (const req_t&);
     };