Multi-hop REQ/REP, part XII., generate unique identities for anonymous connections

6 files changed, 38 insertions, 28 deletions

diff --git a/src/options.cpp b/src/options.cpp
index b77af24..f78d8de 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -77,6 +77,15 @@ int zmq::options_t::setsockopt (int option_, const void *optval_,
         return 0;
 
     case ZMQ_IDENTITY:
+
+        //  Empty identity is invalid as well as identity longer than
+        //  255 bytes. Identity starting with binary zero is invalid
+        //  as these are used for auto-generated identities.
+        if (optvallen_ < 1 || optvallen_ > 255 ||
+              *((const unsigned char*) optval_) == 0) {
+            errno = EINVAL;
+            return -1;
+        }
         identity.assign ((const unsigned char*) optval_, optvallen_);
         return 0;
 
diff --git a/src/session.cpp b/src/session.cpp
index 74bd8ae..05f319c 100644
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -50,7 +50,7 @@ zmq::session_t::session_t (object_t *parent_, socket_base_t *owner_,
     peer_identity (peer_identity_),
     options (options_)
 {
-    if (!peer_identity.empty ()) {
+    if (!peer_identity.empty () && peer_identity [0] != 0) {
         if (!owner->register_session (peer_identity, this)) {
 
             //  TODO: There's already a session with the specified
@@ -103,7 +103,7 @@ void zmq::session_t::detach (owned_t *reconnecter_)
     engine = NULL;
 
     //  Terminate transient session.
-    if (!ordinal && peer_identity.empty ())
+    if (!ordinal && (peer_identity.empty () || peer_identity [0] == 0))
         term ();
 }
 
@@ -173,7 +173,7 @@ void zmq::session_t::process_unplug ()
     //  Unregister the session from the socket.
     if (ordinal)
         owner->unregister_session (ordinal);
-    else if (!peer_identity.empty ())
+    else if (!peer_identity.empty () && peer_identity [0] != 0)
         owner->unregister_session (peer_identity);
 
     //  Ask associated pipes to terminate.
diff --git a/src/uuid.hpp b/src/uuid.hpp
index 001ea94..f565f8d 100644
--- a/src/uuid.hpp
+++ b/src/uuid.hpp
@@ -44,6 +44,9 @@ namespace zmq
         uuid_t ();
         ~uuid_t ();
 
+        //  The length of textual representation of UUID.
+        enum { uuid_string_len = 36 };
+
         //  Returns a pointer to buffer containing the textual
         //  representation of the UUID. The caller is reponsible to
         //  free the allocated memory.
@@ -51,9 +54,6 @@ namespace zmq
 
     private:
 
-        //  The length of textual representation of UUID.
-        enum { uuid_string_len = 36 };
-
 #if defined ZMQ_HAVE_WINDOWS
 #ifdef ZMQ_HAVE_MINGW32
         typedef unsigned char* RPC_CSTR;
diff --git a/src/zmq_encoder.cpp b/src/zmq_encoder.cpp
index 5fca182..68626fa 100644
--- a/src/zmq_encoder.cpp
+++ b/src/zmq_encoder.cpp
@@ -89,7 +89,6 @@ bool zmq::zmq_encoder_t::message_ready ()
         size -= prefix_size;
     }
 
-
     //  For messages less than 255 bytes long, write one byte of message size.
     //  For longer messages write 0xff escape character followed by 8-byte
     //  message size.
diff --git a/src/zmq_engine.cpp b/src/zmq_engine.cpp
index 152daf6..623ca63 100644
--- a/src/zmq_engine.cpp
+++ b/src/zmq_engine.cpp
@@ -17,6 +17,8 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <string.h>
+
 #include <new>
 
 #include "zmq_engine.hpp"
@@ -161,7 +163,7 @@ void zmq::zmq_engine_t::revive ()
 }
 
 void zmq::zmq_engine_t::add_prefix (const blob_t &identity_)
-{    
+{
     decoder.add_prefix (identity_);
 }
 
diff --git a/src/zmq_init.cpp b/src/zmq_init.cpp
index 7c5588f..3e76cb9 100644
--- a/src/zmq_init.cpp
+++ b/src/zmq_init.cpp
@@ -17,10 +17,13 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <string.h>
+
 #include "zmq_init.hpp"
 #include "zmq_engine.hpp"
 #include "io_thread.hpp"
 #include "session.hpp"
+#include "uuid.hpp"
 #include "err.hpp"
 
 zmq::zmq_init_t::zmq_init_t (io_thread_t *parent_, socket_base_t *owner_,
@@ -71,10 +74,19 @@ bool zmq::zmq_init_t::write (::zmq_msg_t *msg_)
     if (received)
         return false;
 
-    //  Retreieve the remote identity.
-    peer_identity.assign ((const unsigned char*) zmq_msg_data (msg_),
-        zmq_msg_size (msg_));
-    engine->add_prefix (peer_identity);
+    //  Retreieve the remote identity. If it's empty, generate a unique name.
+    if (!zmq_msg_size (msg_)) {
+        unsigned char identity [uuid_t::uuid_string_len + 1];
+        identity [0] = 0;
+        memcpy (identity + 1, uuid_t ().to_string (), uuid_t::uuid_string_len);
+        peer_identity.assign (identity, uuid_t::uuid_string_len + 1);
+    }
+    else {
+        peer_identity.assign ((const unsigned char*) zmq_msg_data (msg_),
+            zmq_msg_size (msg_));
+    }
+    if (options.traceroute)
+        engine->add_prefix (peer_identity);
     received = true;
 
     return true;
@@ -155,10 +167,11 @@ void zmq::zmq_init_t::finalise ()
                 return;
             }
         }
+        else {
 
-        //  If the peer has a unique name, find the associated session. If it
-        //  doesn't exist, create it.
-        else if (!peer_identity.empty ()) {
+            //  If the peer has a unique name, find the associated session.
+            //  If it does not exist, create it.
+            zmq_assert (!peer_identity.empty ());
             session = owner->find_session (peer_identity);
             if (!session) {
                 session = new (std::nothrow) session_t (
@@ -173,19 +186,6 @@ void zmq::zmq_init_t::finalise ()
             }
         }
 
-        //  If the other party has no specific identity, let's create a
-        //  transient session.
-        else {
-            session = new (std::nothrow) session_t (
-                choose_io_thread (options.affinity), owner, options, blob_t ());
-            zmq_assert (session);
-            send_plug (session);
-            send_own (owner, session);
-
-            //  Reserve a sequence number for following 'attach' command.
-            session->inc_seqnum ();
-        }
-
         //  No need to increment seqnum as it was already incremented above.
         send_attach (session, engine, peer_identity, false);