ZMQ_IDENTITY socket option removed

This patch simplifies the whole codebase significantly,
including dropping depedency on libuuid.

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

41 files changed, 112 insertions, 949 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index e78eb1c..5049ad8 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -35,7 +35,6 @@ libzmq_la_SOURCES = \
     msg.hpp \
     mtrie.hpp \
     mutex.hpp \
-    named_session.hpp \
     object.hpp \
     options.hpp \
     own.hpp \
@@ -68,7 +67,6 @@ libzmq_la_SOURCES = \
     thread.hpp \
     transient_session.hpp \
     trie.hpp \
-    uuid.hpp \
     windows.hpp \
     wire.hpp \
     xpub.hpp \
@@ -79,10 +77,8 @@ libzmq_la_SOURCES = \
     yqueue.hpp \
     zmq_connecter.hpp \
     zmq_engine.hpp \
-    zmq_init.hpp \
     zmq_listener.hpp \
     clock.cpp \
-    command.cpp \
     ctx.cpp \
     connect_session.cpp \
     decoder.cpp \
@@ -100,7 +96,6 @@ libzmq_la_SOURCES = \
     mailbox.cpp \
     msg.cpp \
     mtrie.cpp \
-    named_session.cpp \
     object.cpp \
     options.cpp \
     own.cpp \
@@ -129,7 +124,6 @@ libzmq_la_SOURCES = \
     thread.cpp \
     transient_session.cpp \
     trie.cpp \
-    uuid.cpp \
     xpub.cpp \
     xrep.cpp \
     xreq.cpp \
@@ -137,7 +131,6 @@ libzmq_la_SOURCES = \
     zmq.cpp \
     zmq_connecter.cpp \
     zmq_engine.cpp \
-    zmq_init.cpp \
     zmq_listener.cpp \
     zmq_utils.cpp
 
diff --git a/src/command.cpp b/src/command.cpp
deleted file mode 100644
index e3f3d59..0000000
--- a/src/command.cpp
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
-    Copyright (c) 2007-2011 iMatix Corporation
-    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
-
-    This file is part of 0MQ.
-
-    0MQ is free software; you can redistribute it and/or modify it under
-    the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 3 of the License, or
-    (at your option) any later version.
-
-    0MQ is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#include <stdlib.h>
-
-#include "command.hpp"
-
-void zmq::deallocate_command (command_t *cmd_)
-{
-    switch (cmd_->type) {
-    case command_t::attach:
-        if (cmd_->args.attach.peer_identity)
-            free (cmd_->args.attach.peer_identity);
-        break;
-    case command_t::bind:
-        if (cmd_->args.bind.peer_identity)
-            free (cmd_->args.bind.peer_identity);
-        break;
-    default:
-        /*  noop  */;
-    }
-}
diff --git a/src/command.hpp b/src/command.hpp
index 15cee0a..1513ca8 100644
--- a/src/command.hpp
+++ b/src/command.hpp
@@ -73,16 +73,12 @@ namespace zmq
             //  session that the connection have failed.
             struct {
                 struct i_engine *engine;
-                unsigned char peer_identity_size;
-                unsigned char *peer_identity;
             } attach;
 
             //  Sent from session to socket to establish pipe(s) between them.
             //  Caller have used inc_seqnum beforehand sending the command.
             struct {
                 class pipe_t *pipe;
-                unsigned char peer_identity_size;
-                unsigned char *peer_identity;
             } bind;
 
             //  Sent by pipe writer to inform dormant pipe reader that there
@@ -146,9 +142,6 @@ namespace zmq
         } args;
     };
 
-    //  Function to deallocate dynamically allocated components of the command.
-    void deallocate_command (command_t *cmd_);
-
 }    
 
 #endif
diff --git a/src/connect_session.cpp b/src/connect_session.cpp
index fe7332a..14666a6 100644
--- a/src/connect_session.cpp
+++ b/src/connect_session.cpp
@@ -29,15 +29,12 @@ zmq::connect_session_t::connect_session_t (class io_thread_t *io_thread_,
       const char *protocol_, const char *address_) :
     session_t (io_thread_, socket_, options_),
     protocol (protocol_),
-    address (address_),
-    connected (false)
+    address (address_)
 {
 }
 
 zmq::connect_session_t::~connect_session_t ()
 {
-    if (connected && !peer_identity.empty ())
-        unregister_session (peer_identity);
 }
 
 void zmq::connect_session_t::process_plug ()
@@ -87,7 +84,7 @@ void zmq::connect_session_t::start_connecting (bool wait_)
             int rc = pgm_sender->init (udp_encapsulation, address.c_str ());
             zmq_assert (rc == 0);
 
-            send_attach (this, pgm_sender, blob_t ());
+            send_attach (this, pgm_sender);
         }
         else if (options.type == ZMQ_SUB || options.type == ZMQ_XSUB) {
 
@@ -99,7 +96,7 @@ void zmq::connect_session_t::start_connecting (bool wait_)
             int rc = pgm_receiver->init (udp_encapsulation, address.c_str ());
             zmq_assert (rc == 0);
 
-            send_attach (this, pgm_receiver, blob_t ());
+            send_attach (this, pgm_receiver);
         }
         else
             zmq_assert (false);
@@ -111,45 +108,8 @@ void zmq::connect_session_t::start_connecting (bool wait_)
     zmq_assert (false);
 }
 
-bool zmq::connect_session_t::xattached (const blob_t &peer_identity_)
+bool zmq::connect_session_t::xattached ()
 {
-    //  If there was no previous connection...
-    if (!connected) {
-
-        //  Peer has transient identity.
-        if (peer_identity_.empty () || peer_identity_ [0] == 0) {
-            connected = true;
-            return true;
-        }
-
-        //  Peer has strong identity. Let's register it and check whether noone
-        //  else is using the same identity.
-        if (!register_session (peer_identity_, this)) {
-            log ("DPID: duplicate peer identity - disconnecting peer");
-            return false;
-        }
-        connected = true;
-        peer_identity = peer_identity_;
-        return true;
-    }
-
-    //  New engine from listener can conflict with existing engine.
-    //  Alternatively, new engine created by reconnection process can
-    //  conflict with engine supplied by listener in the meantime.
-    if (has_engine ()) {
-        log ("DPID: duplicate peer identity - disconnecting peer");
-        return false;
-    }
-
-    //  If there have been a connection before, we have to check whether
-    //  peer's identity haven't changed in the meantime.
-    if ((peer_identity_.empty () || peer_identity_ [0] == 0) &&
-          peer_identity.empty ())
-        return true;
-    if (peer_identity != peer_identity_) {
-        log ("CHID: peer have changed identity - disconnecting peer");
-        return false;
-    }
     return true;
 }
 
diff --git a/src/connect_session.hpp b/src/connect_session.hpp
index 3b8a26b..bc25d26 100644
--- a/src/connect_session.hpp
+++ b/src/connect_session.hpp
@@ -44,7 +44,7 @@ namespace zmq
     private:
 
         //  Handlers for events from session base class.
-        bool xattached (const blob_t &peer_identity_);
+        bool xattached ();
         bool xdetached ();
 
         //  Start the connection process.
@@ -57,13 +57,6 @@ namespace zmq
         std::string protocol;
         std::string address;
 
-        //  If true, the session was already connected to the peer.
-        bool connected;
-
-        //  Identity of the peer. If 'connected' is false, it has no meaning.
-        //  Otherwise, if it's empty, the peer has transient identity.
-        blob_t peer_identity;
-
         connect_session_t (const connect_session_t&);
         const connect_session_t &operator = (const connect_session_t&);
     };
diff --git a/src/named_session.cpp b/src/named_session.cpp
deleted file mode 100644
index 8e43fb0..0000000
--- a/src/named_session.cpp
+++ /dev/null
@@ -1,67 +0,0 @@
-/*
-    Copyright (c) 2007-2011 iMatix Corporation
-    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
-
-    This file is part of 0MQ.
-
-    0MQ is free software; you can redistribute it and/or modify it under
-    the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 3 of the License, or
-    (at your option) any later version.
-
-    0MQ is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#include "named_session.hpp"
-#include "socket_base.hpp"
-
-zmq::named_session_t::named_session_t (class io_thread_t *io_thread_,
-      socket_base_t *socket_, const options_t &options_,
-      const blob_t &peer_identity_) :
-    session_t (io_thread_, socket_, options_),
-    peer_identity (peer_identity_)
-{
-    //  Make double sure that the peer's identity is not transient.
-    zmq_assert (!peer_identity.empty ());
-    zmq_assert (peer_identity [0] != 0);
-
-    bool ok = socket_->register_session (peer_identity, this);
-
-    //  If new session is being created, the caller should have already
-    //  checked that the session for specified identity doesn't exist yet.
-    //  Thus, register_session should not fail.
-    zmq_assert (ok);
-}
-
-zmq::named_session_t::~named_session_t ()
-{
-    //  Unregister the session from the global list of named sessions.
-    unregister_session (peer_identity);
-}
-
-bool zmq::named_session_t::xattached (const blob_t &peer_identity_)
-{
-    //  Double check that identities match.
-    zmq_assert (peer_identity == peer_identity_);
-
-    //  If the session already has an engine attached, destroy new one.
-    if (has_engine ()) {
-        log ("DPID: duplicate peer identity - disconnecting peer");
-        return false;
-    }
-    return true;
-}
-
-bool zmq::named_session_t::xdetached ()
-{
-    //  Do nothing. Named sessions are never destroyed because of disconnection.
-    //  Neither they have to actively reconnect.
-    return true;
-}
-
diff --git a/src/named_session.hpp b/src/named_session.hpp
deleted file mode 100644
index 10af8cc..0000000
--- a/src/named_session.hpp
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
-    Copyright (c) 2007-2011 iMatix Corporation
-    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
-
-    This file is part of 0MQ.
-
-    0MQ is free software; you can redistribute it and/or modify it under
-    the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 3 of the License, or
-    (at your option) any later version.
-
-    0MQ is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#ifndef __ZMQ_NAMED_SESSION_HPP_INCLUDED__
-#define __ZMQ_NAMED_SESSION_HPP_INCLUDED__
-
-#include "session.hpp"
-#include "blob.hpp"
-
-namespace zmq
-{
-
-    //  Named session is created by listener object when the peer identifies
-    //  itself by a strong name. Named session survives reconnections.
-
-    class named_session_t : public session_t
-    {
-    public:
-
-        named_session_t (class io_thread_t *io_thread_,
-            class socket_base_t *socket_, const options_t &options_, 
-            const blob_t &peer_identity_);
-        ~named_session_t ();
-
-        //  Handlers for events from session base class.
-        bool xattached (const blob_t &peer_identity_);
-        bool xdetached ();
-
-    private:
-
-        blob_t peer_identity;
-
-        named_session_t (const named_session_t&);
-        const named_session_t &operator = (const named_session_t&);
-    };
-
-}
-
-#endif
diff --git a/src/object.cpp b/src/object.cpp
index ba77bf0..7f7d7f8 100644
--- a/src/object.cpp
+++ b/src/object.cpp
@@ -82,17 +82,12 @@ void zmq::object_t::process_command (command_t &cmd_)
         break;
 
     case command_t::attach:
-        process_attach (cmd_.args.attach.engine,
-            cmd_.args.attach.peer_identity ?
-            blob_t (cmd_.args.attach.peer_identity,
-            cmd_.args.attach.peer_identity_size) : blob_t ());
+        process_attach (cmd_.args.attach.engine);
         process_seqnum ();
         break;
 
     case command_t::bind:
-        process_bind (cmd_.args.bind.pipe, cmd_.args.bind.peer_identity ?
-            blob_t (cmd_.args.bind.peer_identity,
-            cmd_.args.bind.peer_identity_size) : blob_t ());
+        process_bind (cmd_.args.bind.pipe);
         process_seqnum ();
         break;
 
@@ -131,10 +126,6 @@ void zmq::object_t::process_command (command_t &cmd_)
     default:
         zmq_assert (false);
     }
-
-    //  The assumption here is that each command is processed once only,
-    //  so deallocating it after processing is all right.
-    deallocate_command (&cmd_);
 }
 
 int zmq::object_t::register_endpoint (const char *addr_, endpoint_t &endpoint_)
@@ -211,7 +202,7 @@ void zmq::object_t::send_own (own_t *destination_, own_t *object_)
 }
 
 void zmq::object_t::send_attach (session_t *destination_, i_engine *engine_,
-    const blob_t &peer_identity_, bool inc_seqnum_)
+    bool inc_seqnum_)
 {
     if (inc_seqnum_)
         destination_->inc_seqnum ();
@@ -223,25 +214,11 @@ void zmq::object_t::send_attach (session_t *destination_, i_engine *engine_,
     cmd.destination = destination_;
     cmd.type = command_t::attach;
     cmd.args.attach.engine = engine_;
-    if (peer_identity_.empty ()) {
-        cmd.args.attach.peer_identity_size = 0;
-        cmd.args.attach.peer_identity = NULL;
-    }
-    else {
-        zmq_assert (peer_identity_.size () <= 0xff);
-        cmd.args.attach.peer_identity_size =
-            (unsigned char) peer_identity_.size ();
-        cmd.args.attach.peer_identity =
-            (unsigned char*) malloc (peer_identity_.size ());
-        alloc_assert (cmd.args.attach.peer_identity_size);
-        memcpy (cmd.args.attach.peer_identity, peer_identity_.data (),
-            peer_identity_.size ());
-    }
     send_command (cmd);
 }
 
 void zmq::object_t::send_bind (own_t *destination_, pipe_t *pipe_,
-    const blob_t &peer_identity_, bool inc_seqnum_)
+    bool inc_seqnum_)
 {
     if (inc_seqnum_)
         destination_->inc_seqnum ();
@@ -253,20 +230,6 @@ void zmq::object_t::send_bind (own_t *destination_, pipe_t *pipe_,
     cmd.destination = destination_;
     cmd.type = command_t::bind;
     cmd.args.bind.pipe = pipe_;
-    if (peer_identity_.empty ()) {
-        cmd.args.bind.peer_identity_size = 0;
-        cmd.args.bind.peer_identity = NULL;
-    }
-    else {
-        zmq_assert (peer_identity_.size () <= 0xff);
-        cmd.args.bind.peer_identity_size =
-            (unsigned char) peer_identity_.size ();
-        cmd.args.bind.peer_identity =
-            (unsigned char*) malloc (peer_identity_.size ());
-        alloc_assert (cmd.args.bind.peer_identity_size);
-        memcpy (cmd.args.bind.peer_identity, peer_identity_.data (),
-            peer_identity_.size ());
-    }
     send_command (cmd);
 }
 
@@ -413,13 +376,12 @@ void zmq::object_t::process_own (own_t *object_)
     zmq_assert (false);
 }
 
-void zmq::object_t::process_attach (i_engine *engine_,
-    const blob_t &peer_identity_)
+void zmq::object_t::process_attach (i_engine *engine_)
 {
     zmq_assert (false);
 }
 
-void zmq::object_t::process_bind (pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::object_t::process_bind (pipe_t *pipe_)
 {
     zmq_assert (false);
 }
diff --git a/src/object.hpp b/src/object.hpp
index fbad0ea..e05b958 100644
--- a/src/object.hpp
+++ b/src/object.hpp
@@ -22,7 +22,6 @@
 #define __ZMQ_OBJECT_HPP_INCLUDED__
 
 #include "stdint.hpp"
-#include "blob.hpp"
 
 namespace zmq
 {
@@ -64,10 +63,9 @@ namespace zmq
         void send_own (class own_t *destination_,
             class own_t *object_);
         void send_attach (class session_t *destination_,
-             struct i_engine *engine_, const blob_t &peer_identity_,
-             bool inc_seqnum_ = true);
+             struct i_engine *engine_, bool inc_seqnum_ = true);
         void send_bind (class own_t *destination_, class pipe_t *pipe_,
-             const blob_t &peer_identity_, bool inc_seqnum_ = true);
+             bool inc_seqnum_ = true);
         void send_activate_read (class pipe_t *destination_);
         void send_activate_write (class pipe_t *destination_,
              uint64_t msgs_read_);
@@ -87,10 +85,8 @@ namespace zmq
         virtual void process_stop ();
         virtual void process_plug ();
         virtual void process_own (class own_t *object_);
-        virtual void process_attach (struct i_engine *engine_,
-            const blob_t &peer_identity_);
-        virtual void process_bind (class pipe_t *pipe_,
-            const blob_t &peer_identity_);
+        virtual void process_attach (struct i_engine *engine_);
+        virtual void process_bind (class pipe_t *pipe_);
         virtual void process_activate_read ();
         virtual void process_activate_write (uint64_t msgs_read_);
         virtual void process_hiccup (void *pipe_);
diff --git a/src/options.cpp b/src/options.cpp
index 63a1d91..45eb4aa 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -75,19 +75,6 @@ int zmq::options_t::setsockopt (int option_, const void *optval_,
         affinity = *((uint64_t*) 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;
-
     case ZMQ_RATE:
         if (optvallen_ != sizeof (int) || *((int*) optval_) <= 0) {
             errno = EINVAL;
@@ -229,15 +216,6 @@ int zmq::options_t::getsockopt (int option_, void *optval_, size_t *optvallen_)
         *optvallen_ = sizeof (uint64_t);
         return 0;
 
-    case ZMQ_IDENTITY:
-        if (*optvallen_ < identity.size ()) {
-            errno = EINVAL;
-            return -1;
-        }
-        memcpy (optval_, identity.data (), identity.size ());
-        *optvallen_ = identity.size ();
-        return 0;
-
     case ZMQ_RATE:
         if (*optvallen_ < sizeof (int)) {
             errno = EINVAL;
diff --git a/src/options.hpp b/src/options.hpp
index f1982da..d8847f5 100644
--- a/src/options.hpp
+++ b/src/options.hpp
@@ -23,7 +23,6 @@
 
 #include "stddef.h"
 #include "stdint.hpp"
-#include "blob.hpp"
 
 namespace zmq
 {
@@ -39,8 +38,8 @@ namespace zmq
         int sndhwm;
         int rcvhwm;
 
+        //  I/O thread affinity.
         uint64_t affinity;
-        blob_t identity;
 
         //  Maximum tranfer rate [kb/s]. Default 100kb/s.
         int rate;
diff --git a/src/pair.cpp b/src/pair.cpp
index 30b56e6..12a1881 100644
--- a/src/pair.cpp
+++ b/src/pair.cpp
@@ -35,7 +35,7 @@ zmq::pair_t::~pair_t ()
     zmq_assert (!pipe);
 }
 
-void zmq::pair_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::pair_t::xattach_pipe (pipe_t *pipe_)
 {
     zmq_assert (!pipe);
     pipe = pipe_;
diff --git a/src/pair.hpp b/src/pair.hpp
index 1ddf50e..59300ae 100644
--- a/src/pair.hpp
+++ b/src/pair.hpp
@@ -35,7 +35,7 @@ namespace zmq
         ~pair_t ();
 
         //  Overloads of functions from socket_base_t.
-        void xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
+        void xattach_pipe (class pipe_t *pipe_);
         int xsend (class msg_t *msg_, int flags_);
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
diff --git a/src/pgm_socket.cpp b/src/pgm_socket.cpp
index 90a265c..98aeeb9 100644
--- a/src/pgm_socket.cpp
+++ b/src/pgm_socket.cpp
@@ -38,7 +38,7 @@
 #include "pgm_socket.hpp"
 #include "config.hpp"
 #include "err.hpp"
-#include "uuid.hpp"
+#include "random.hpp"
 #include "stdint.hpp"
 
 #ifndef MSG_ERRQUEUE
@@ -253,20 +253,13 @@ int zmq::pgm_socket_t::init (bool udp_encapsulation_, const char *network_)
     addr.sa_port = port_number;
     addr.sa_addr.sport = DEFAULT_DATA_SOURCE_PORT;
 
-    if (options.identity.size () > 0) {
-
-        //  Create gsi from identity.
-        if (!pgm_gsi_create_from_data (&addr.sa_addr.gsi,
-              options.identity.data (), options.identity.size ()))
-            goto err_abort;
-    } else {
+    //  Create random GSI.
+    uint32_t buf [2];
+    buf [0] = generate_random ();
+    buf [1] = generate_random ();
+    if (!pgm_gsi_create_from_data (&addr.sa_addr.gsi, (uint8_t*) buf, 8))
+        goto err_abort;
 
-        //  Generate GSI from UUID.
-        unsigned char buf [16];
-        generate_uuid (buf);
-        if (!pgm_gsi_create_from_data (&addr.sa_addr.gsi, buf, 16))
-            goto err_abort;
-    }
 
     //  Bind a transport to the specified network devices.
     struct pgm_interface_req_t if_req;
diff --git a/src/pull.cpp b/src/pull.cpp
index 5e48777..afde236 100644
--- a/src/pull.cpp
+++ b/src/pull.cpp
@@ -33,7 +33,7 @@ zmq::pull_t::~pull_t ()
 {
 }
 
-void zmq::pull_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::pull_t::xattach_pipe (pipe_t *pipe_)
 {
     zmq_assert (pipe_);
     fq.attach (pipe_);
diff --git a/src/pull.hpp b/src/pull.hpp
index cbcf05a..be82af9 100644
--- a/src/pull.hpp
+++ b/src/pull.hpp
@@ -38,7 +38,7 @@ namespace zmq
     protected:
 
         //  Overloads of functions from socket_base_t.
-        void xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
+        void xattach_pipe (class pipe_t *pipe_);
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
         void xread_activated (class pipe_t *pipe_);
diff --git a/src/push.cpp b/src/push.cpp
index 44ebc07..77cc9d8 100644
--- a/src/push.cpp
+++ b/src/push.cpp
@@ -33,7 +33,7 @@ zmq::push_t::~push_t ()
 {
 }
 
-void zmq::push_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::push_t::xattach_pipe (pipe_t *pipe_)
 {
     zmq_assert (pipe_);
     lb.attach (pipe_);
diff --git a/src/push.hpp b/src/push.hpp
index 5dabe14..222a62d 100644
--- a/src/push.hpp
+++ b/src/push.hpp
@@ -38,7 +38,7 @@ namespace zmq
     protected:
 
         //  Overloads of functions from socket_base_t.
-        void xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
+        void xattach_pipe (class pipe_t *pipe_);
         int xsend (class msg_t *msg_, int flags_);
         bool xhas_out ();
         void xwrite_activated (class pipe_t *pipe_);
diff --git a/src/random.cpp b/src/random.cpp
index 2a1d7d6..9f7768c 100644
--- a/src/random.cpp
+++ b/src/random.cpp
@@ -18,23 +18,35 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <stdlib.h>
+
+#include "platform.hpp"
+#if defined ZMQ_HAVE_WINDOWS
+#include "windows.hpp"
+#else
+#include <unistd.h>
+#endif
+
 #include "random.hpp"
 #include "stdint.hpp"
-#include "uuid.hpp"
-#include "err.hpp"
+#include "clock.hpp"
+
+void zmq::seed_random ()
+{
+#if defined ZMQ_HAVE_WINDOWS
+    int pid = (int) GetCurrentProcessId ();
+#else
+    int pid = (int) getpid ();
+#endif
+    srand ((unsigned int) (clock_t::now_us () + pid));
+}
 
-//  Here we can use different ways of generating random data, as avialable
-//  on different platforms. At the moment, we'll assume the UUID is random
-//  enough to use for that purpose.
-void zmq::generate_random (void *buf_, size_t size_)
+uint32_t zmq::generate_random ()
 {
-    //  Collapsing an UUID into 4 bytes.
-    zmq_assert (size_ == 4);
-    uint32_t buff [4];
-    generate_uuid ((void*) buff);
-    uint32_t result = buff [0];
-    result ^= buff [1];
-    result ^= buff [2];
-    result ^= buff [3];
-    *((uint32_t*) buf_) = result;
+    //  Compensate for the fact that rand() returns signed integer.
+    uint32_t low = (uint32_t) rand ();
+    uint32_t high = (uint32_t) rand ();
+    high <<= (sizeof (int) * 8 - 1);
+    return high | low;
 }
+
diff --git a/src/random.hpp b/src/random.hpp
index 0b99bbd..d88b5ee 100644
--- a/src/random.hpp
+++ b/src/random.hpp
@@ -21,13 +21,16 @@
 #ifndef __ZMQ_RANDOM_HPP_INCLUDED__
 #define __ZMQ_RANDOM_HPP_INCLUDED__
 
-#include <stddef.h>
+#include "stdint.hpp"
 
 namespace zmq
 {
 
-    //  Generates truly random bytes (not pseudo-random).
-    void generate_random (void *buf_, size_t size_);
+    //  Seeds the random number generator.
+    void seed_random ();
+
+    //  Generates random value.
+    uint32_t generate_random ();
 
 }
 
diff --git a/src/req.cpp b/src/req.cpp
index e0e3321..7831672 100644
--- a/src/req.cpp
+++ b/src/req.cpp
@@ -21,7 +21,6 @@
 #include "req.hpp"
 #include "err.hpp"
 #include "msg.hpp"
-#include "uuid.hpp"
 #include "wire.hpp"
 #include "random.hpp"
 #include "likely.hpp"
@@ -30,12 +29,9 @@ zmq::req_t::req_t (class ctx_t *parent_, uint32_t tid_) :
     xreq_t (parent_, tid_),
     receiving_reply (false),
     message_begins (true),
-    request_id (0)
+    request_id (generate_random ())
 {
     options.type = ZMQ_REQ;
-
-    //  Start the request ID sequence at an random point.
-    generate_random (&request_id, sizeof (request_id));
 }
 
 zmq::req_t::~req_t ()
diff --git a/src/session.cpp b/src/session.cpp
index 1ca69cf..0dd0e34 100644
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -159,8 +159,7 @@ void zmq::session_t::process_plug ()
 {
 }
 
-void zmq::session_t::process_attach (i_engine *engine_,
-    const blob_t &peer_identity_)
+void zmq::session_t::process_attach (i_engine *engine_)
 {
     //  If some other object (e.g. init) notifies us that the connection failed
     //  without creating an engine we need to start the reconnection process.
@@ -171,7 +170,7 @@ void zmq::session_t::process_attach (i_engine *engine_,
     }
 
     //  Trigger the notfication event about the attachment.
-    if (!attached (peer_identity_)) {
+    if (!attached ()) {
         delete engine_;
         return;
     }
@@ -193,7 +192,7 @@ void zmq::session_t::process_attach (i_engine *engine_,
         pipe = pipes [0];
 
         //  Ask socket to plug into the remote end of the pipe.
-        send_bind (socket, pipes [1], peer_identity_);
+        send_bind (socket, pipes [1]);
     }
 
     //  Plug in the engine.
@@ -272,24 +271,9 @@ void zmq::session_t::timer_event (int id_)
     pipe->terminate (false);
 }
 
-bool zmq::session_t::has_engine ()
+bool zmq::session_t::attached ()
 {
-    return engine != NULL;
-}
-
-bool zmq::session_t::register_session (const blob_t &name_, session_t *session_)
-{
-    return socket->register_session (name_, session_);
-}
-
-void zmq::session_t::unregister_session (const blob_t &name_)
-{
-    socket->unregister_session (name_);
-}
-
-bool zmq::session_t::attached (const blob_t &peer_identity_)
-{
-    return xattached (peer_identity_);
+    return xattached ();
 }
 
 void zmq::session_t::detached ()
diff --git a/src/session.hpp b/src/session.hpp
index 4c17930..60aa7c5 100644
--- a/src/session.hpp
+++ b/src/session.hpp
@@ -24,7 +24,6 @@
 #include "own.hpp"
 #include "i_engine.hpp"
 #include "io_object.hpp"
-#include "blob.hpp"
 #include "pipe.hpp"
 
 namespace zmq
@@ -64,27 +63,19 @@ namespace zmq
         //  the termination process when session is about to be detached from
         //  the peer. If it returns false, session will be terminated.
         //  To be overloaded by the derived session type.
-        virtual bool xattached (const blob_t &peer_identity_) = 0;
+        virtual bool xattached () = 0;
         virtual bool xdetached () = 0;
 
-        //  Returns true if there is an engine attached to the session.
-        bool has_engine ();
-
-        //  Allows derives session types to (un)register session names.
-        bool register_session (const blob_t &name_, class session_t *session_);
-        void unregister_session (const blob_t &name_);
-
         ~session_t ();
 
     private:
 
-        bool attached (const blob_t &peer_identity_);
+        bool attached ();
         void detached ();
 
         //  Handlers for incoming commands.
         void process_plug ();
-        void process_attach (struct i_engine *engine_,
-            const blob_t &peer_identity_);
+        void process_attach (struct i_engine *engine_);
         void process_term (int linger_);
 
         //  i_poll_events handlers.
diff --git a/src/socket_base.cpp b/src/socket_base.cpp
index 1bc80f1..bc58e8b 100644
--- a/src/socket_base.cpp
+++ b/src/socket_base.cpp
@@ -45,7 +45,6 @@
 #include "ctx.hpp"
 #include "platform.hpp"
 #include "likely.hpp"
-#include "uuid.hpp"
 #include "msg.hpp"
 
 #include "pair.hpp"
@@ -128,11 +127,6 @@ zmq::socket_base_t::~socket_base_t ()
 {
     zmq_assert (destroyed);
 
-    //  Check whether there are no session leaks.
-    sessions_sync.lock ();
-    zmq_assert (sessions.empty ());
-    sessions_sync.unlock ();
-
     //  Mark the socket as dead.
     tag = 0xdeadbeef;
 }
@@ -212,23 +206,14 @@ int zmq::socket_base_t::check_protocol (const std::string &protocol_)
     return 0;
 }
 
-void zmq::socket_base_t::attach_pipe (pipe_t *pipe_,
-    const blob_t &peer_identity_)
+void zmq::socket_base_t::attach_pipe (pipe_t *pipe_)
 {
     //  First, register the pipe so that we can terminate it later on.
     pipe_->set_event_sink (this);
     pipes.push_back (pipe_);
     
-    //  Then, pass the pipe to the specific socket type.
-    //  If the peer haven't specified it's identity, let's generate one.
-    if (peer_identity_.size ()) {
-        xattach_pipe (pipe_, peer_identity_);
-    }
-    else {
-        blob_t identity (17, 0);
-        generate_uuid ((unsigned char*) identity.data () + 1);
-        xattach_pipe (pipe_, identity);
-    }
+    //  Let the derived socket type know about new pipe.
+    xattach_pipe (pipe_);
 
     //  If the socket is already being closed, ask any new pipes to terminate
     //  straight away.
@@ -423,12 +408,12 @@ int zmq::socket_base_t::connect (const char *addr_)
         errno_assert (rc == 0);
 
         //  Attach local end of the pipe to this socket object.
-        attach_pipe (pipes [0], peer.options.identity);
+        attach_pipe (pipes [0]);
 
         //  Attach remote end of the pipe to the peer socket. Note that peer's
         //  seqnum was incremented in find_endpoint function. We don't need it
         //  increased here.
-        send_bind (peer.socket, pipes [1], options.identity, false);
+        send_bind (peer.socket, pipes [1], false);
 
         return 0;
     }
@@ -454,7 +439,7 @@ int zmq::socket_base_t::connect (const char *addr_)
     errno_assert (rc == 0);
 
     //  Attach local end of the pipe to the socket object.
-    attach_pipe (pipes [0], blob_t ());
+    attach_pipe (pipes [0]);
 
     //  Attach remote end of the pipe to the session object later on.
     session->attach_pipe (pipes [1]);
@@ -654,44 +639,6 @@ bool zmq::socket_base_t::has_out ()
     return xhas_out ();
 }
 
-bool zmq::socket_base_t::register_session (const blob_t &name_,
-    session_t *session_)
-{
-    sessions_sync.lock ();
-    bool registered = sessions.insert (
-        sessions_t::value_type (name_, session_)).second;
-    sessions_sync.unlock ();
-    return registered;
-}
-
-void zmq::socket_base_t::unregister_session (const blob_t &name_)
-{
-    sessions_sync.lock ();
-    sessions_t::iterator it = sessions.find (name_);
-    zmq_assert (it != sessions.end ());
-    sessions.erase (it);
-    sessions_sync.unlock ();
-}
-
-zmq::session_t *zmq::socket_base_t::find_session (const blob_t &name_)
-{
-    sessions_sync.lock ();
-    sessions_t::iterator it = sessions.find (name_);
-    if (it == sessions.end ()) {
-        sessions_sync.unlock ();
-        return NULL;
-    }
-    session_t *session = it->second;
-
-    //  Prepare the session for subsequent attach command.
-    //  Note the connect sessions have NULL pointers registered here.
-    if (session)
-        session->inc_seqnum ();
-
-    sessions_sync.unlock ();
-    return session;    
-}
-
 void zmq::socket_base_t::start_reaping (poller_t *poller_)
 {
     //  Plug the socket to the reaper thread.
@@ -770,10 +717,9 @@ void zmq::socket_base_t::process_stop ()
     ctx_terminated = true;
 }
 
-void zmq::socket_base_t::process_bind (pipe_t *pipe_,
-    const blob_t &peer_identity_)
+void zmq::socket_base_t::process_bind (pipe_t *pipe_)
 {
-    attach_pipe (pipe_, peer_identity_);
+    attach_pipe (pipe_);
 }
 
 void zmq::socket_base_t::process_unplug ()
diff --git a/src/socket_base.hpp b/src/socket_base.hpp
index f114e9d..fb60bbe 100644
--- a/src/socket_base.hpp
+++ b/src/socket_base.hpp
@@ -21,21 +21,17 @@
 #ifndef __ZMQ_SOCKET_BASE_HPP_INCLUDED__
 #define __ZMQ_SOCKET_BASE_HPP_INCLUDED__
 
-#include <map>
-#include <vector>
+#include <string>
 
 #include "own.hpp"
 #include "array.hpp"
-#include "mutex.hpp"
 #include "stdint.hpp"
 #include "poller.hpp"
 #include "atomic_counter.hpp"
 #include "i_poll_events.hpp"
 #include "mailbox.hpp"
 #include "stdint.hpp"
-#include "blob.hpp"
 #include "pipe.hpp"
-#include "own.hpp"
 
 namespace zmq
 {
@@ -78,11 +74,6 @@ namespace zmq
         bool has_in ();
         bool has_out ();
 
-        //  Registry of named sessions.
-        bool register_session (const blob_t &name_, class session_t *session_);
-        void unregister_session (const blob_t &name_);
-        class session_t *find_session (const blob_t &name_);
-
         //  Using this function reaper thread ask the socket to regiter with
         //  its poller.
         void start_reaping (poller_t *poller_);
@@ -106,8 +97,7 @@ namespace zmq
 
         //  Concrete algorithms for the x- methods are to be defined by
         //  individual socket types.
-        virtual void xattach_pipe (class pipe_t *pipe_,
-            const blob_t &peer_identity_) = 0;
+        virtual void xattach_pipe (class pipe_t *pipe_) = 0;
 
         //  The default implementation assumes there are no specific socket
         //  options for the particular socket type. If not so, overload this
@@ -158,7 +148,7 @@ namespace zmq
         int check_protocol (const std::string &protocol_);
 
         //  Register the pipe with this socket.
-        void attach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
+        void attach_pipe (class pipe_t *pipe_);
 
         //  Processes commands sent to this socket (if any). If timeout is -1,
         //  returns only after at least one command was processed.
@@ -168,7 +158,7 @@ namespace zmq
 
         //  Handlers for incoming commands.
         void process_stop ();
-        void process_bind (class pipe_t *pipe_, const blob_t &peer_identity_);
+        void process_bind (class pipe_t *pipe_);
         void process_unplug ();
         void process_term (int linger_);
 
@@ -195,14 +185,6 @@ namespace zmq
         //  True if the last message received had MORE flag set.
         bool rcvmore;
 
-        //  Lists of existing sessions. This list is never referenced from
-        //  within the socket, instead it is used by objects owned by
-        //  the socket. As those objects can live in different threads,
-        //  the access is synchronised by mutex.
-        typedef std::map <blob_t, session_t*> sessions_t;
-        sessions_t sessions;
-        mutex_t sessions_sync;
-
         socket_base_t (const socket_base_t&);
         const socket_base_t &operator = (const socket_base_t&);
     };
diff --git a/src/transient_session.cpp b/src/transient_session.cpp
index b3c80b0..d389ff4 100644
--- a/src/transient_session.cpp
+++ b/src/transient_session.cpp
@@ -30,7 +30,7 @@ zmq::transient_session_t::~transient_session_t ()
 {
 }
 
-bool zmq::transient_session_t::xattached (const blob_t &peer_identity_)
+bool zmq::transient_session_t::xattached ()
 {
     //  Transient session is always valid.
     return true;
diff --git a/src/transient_session.hpp b/src/transient_session.hpp
index 55c2b8a..eff6b65 100644
--- a/src/transient_session.hpp
+++ b/src/transient_session.hpp
@@ -40,7 +40,7 @@ namespace zmq
     private:
 
         //  Handlers for events from session base class.
-        bool xattached (const blob_t &peer_identity_);
+        bool xattached ();
         bool xdetached ();
 
         transient_session_t (const transient_session_t&);
diff --git a/src/uuid.cpp b/src/uuid.cpp
deleted file mode 100644
index 02f716e..0000000
--- a/src/uuid.cpp
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
-    Copyright (c) 2007-2011 iMatix Corporation
-    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
-
-    This file is part of 0MQ.
-
-    0MQ is free software; you can redistribute it and/or modify it under
-    the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 3 of the License, or
-    (at your option) any later version.
-
-    0MQ is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#include <string.h>
-
-#include "uuid.hpp"
-#include "err.hpp"
-#include "stdint.hpp"
-#include "platform.hpp"
-
-#if defined ZMQ_HAVE_WINDOWS
-
-#include <rpc.h>
-
-void zmq::generate_uuid (void *buf_)
-{
-    RPC_STATUS ret = UuidCreate ((::UUID*) buf_);
-    zmq_assert (ret == RPC_S_OK);
-}
-
-#elif defined ZMQ_HAVE_FREEBSD || defined ZMQ_HAVE_NETBSD
-
-#include <uuid.h>
-
-void zmq::generate_uuid (void *buf_)
-{
-    uint32_t status;
-    uuid_create ((::uuid_t*) buf_, &status);
-    zmq_assert (status == uuid_s_ok);
-}
-
-#elif defined ZMQ_HAVE_LINUX || defined ZMQ_HAVE_SOLARIS ||\
-      defined ZMQ_HAVE_OSX || defined ZMQ_HAVE_CYGWIN
-
-#include <uuid/uuid.h>
-
-void zmq::generate_uuid (void *buf_)
-{
-    uuid_generate ((unsigned char*) buf_);
-}
-
-#elif defined ZMQ_HAVE_OPENVMS
-
-#include <starlet.h>
-
-void zmq::generate_uuid (void *buf_)
-{
-    sys$create_uid(buf_);
-}
-
-#else
-
-#include <openssl/rand.h>
-
-void zmq::generate_uuid (void *buf_)
-{
-    unsigned char *buf = (unsigned char*) buf_;
-
-    //  Generate random value.
-    int ret = RAND_bytes (buf, 16);
-    zmq_assert (ret == 1);
-
-    //  Set UUID variant to 2 (UUID as specified in RFC4122).
-    const unsigned char variant = 2;
-    buf [8] = (buf [8] & 0x3f) | (variant << 6);
-
-    //  Set UUID version to 4 (randomly or pseudo-randomly generated UUID).
-    const unsigned char version = 4;
-    buf [6] = (buf [6] & 0x0f) | (version << 4);
-}
-
-#endif
-
diff --git a/src/uuid.hpp b/src/uuid.hpp
deleted file mode 100644
index c338208..0000000
--- a/src/uuid.hpp
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
-    Copyright (c) 2007-2011 iMatix Corporation
-    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
-
-    This file is part of 0MQ.
-
-    0MQ is free software; you can redistribute it and/or modify it under
-    the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 3 of the License, or
-    (at your option) any later version.
-
-    0MQ is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#ifndef __ZMQ_UUID_HPP_INCLUDED__
-#define __ZMQ_UUID_HPP_INCLUDED__
-
-namespace zmq
-{
-
-    //  This function provides RFC 4122 (a Universally Unique IDentifier)
-    //  implementation. The resulting UUID will be 16 bytes long.
-    void generate_uuid (void *buf_);
-
-}
-
-#endif
diff --git a/src/xpub.cpp b/src/xpub.cpp
index 7e4eecc..8da9cf9 100644
--- a/src/xpub.cpp
+++ b/src/xpub.cpp
@@ -36,7 +36,7 @@ zmq::xpub_t::~xpub_t ()
 {
 }
 
-void zmq::xpub_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::xpub_t::xattach_pipe (pipe_t *pipe_)
 {
     zmq_assert (pipe_);
     dist.attach (pipe_);
diff --git a/src/xpub.hpp b/src/xpub.hpp
index a2e7335..320a1fe 100644
--- a/src/xpub.hpp
+++ b/src/xpub.hpp
@@ -41,7 +41,7 @@ namespace zmq
         ~xpub_t ();
 
         //  Implementations of virtual functions from socket_base_t.
-        void xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
+        void xattach_pipe (class pipe_t *pipe_);
         int xsend (class msg_t *msg_, int flags_);
         bool xhas_out ();
         int xrecv (class msg_t *msg_, int flags_);
diff --git a/src/xrep.cpp b/src/xrep.cpp
index 153be46..9b57435 100644
--- a/src/xrep.cpp
+++ b/src/xrep.cpp
@@ -29,7 +29,8 @@ zmq::xrep_t::xrep_t (class ctx_t *parent_, uint32_t tid_) :
     prefetched (false),
     more_in (false),
     current_out (NULL),
-    more_out (false)
+    more_out (false),
+    next_peer_id (generate_random ())
 {
     options.type = ZMQ_XREP;
 
@@ -38,9 +39,6 @@ zmq::xrep_t::xrep_t (class ctx_t *parent_, uint32_t tid_) :
     options.delay_on_disconnect = false;
 
     prefetched_msg.init ();
-
-    //  Start the peer ID sequence from a random point.
-    generate_random (&next_peer_id, sizeof (next_peer_id));
 }
 
 zmq::xrep_t::~xrep_t ()
@@ -49,7 +47,7 @@ zmq::xrep_t::~xrep_t ()
     prefetched_msg.close ();
 }
 
-void zmq::xrep_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::xrep_t::xattach_pipe (pipe_t *pipe_)
 {
     zmq_assert (pipe_);
 
diff --git a/src/xrep.hpp b/src/xrep.hpp
index 41c06b8..07f10ba 100644
--- a/src/xrep.hpp
+++ b/src/xrep.hpp
@@ -41,8 +41,7 @@ namespace zmq
         ~xrep_t ();
 
         //  Overloads of functions from socket_base_t.
-        void xattach_pipe (class pipe_t *pipe_,
-            const blob_t &peer_identity_);
+        void xattach_pipe (class pipe_t *pipe_);
         int xsend (class msg_t *msg_, int flags_);
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
diff --git a/src/xreq.cpp b/src/xreq.cpp
index 85e2238..7b66137 100644
--- a/src/xreq.cpp
+++ b/src/xreq.cpp
@@ -36,7 +36,7 @@ zmq::xreq_t::~xreq_t ()
 {
 }
 
-void zmq::xreq_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::xreq_t::xattach_pipe (pipe_t *pipe_)
 {
     zmq_assert (pipe_);
     fq.attach (pipe_);
diff --git a/src/xreq.hpp b/src/xreq.hpp
index 5bf1a03..a427ba9 100644
--- a/src/xreq.hpp
+++ b/src/xreq.hpp
@@ -40,7 +40,7 @@ namespace zmq
     protected:
 
         //  Overloads of functions from socket_base_t.
-        void xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
+        void xattach_pipe (class pipe_t *pipe_);
         int xsend (class msg_t *msg_, int flags_);
         int xrecv (class msg_t *msg_, int flags_);
         bool xhas_in ();
diff --git a/src/xsub.cpp b/src/xsub.cpp
index 98abc87..cf51cdb 100644
--- a/src/xsub.cpp
+++ b/src/xsub.cpp
@@ -39,7 +39,7 @@ zmq::xsub_t::~xsub_t ()
     errno_assert (rc == 0);
 }
 
-void zmq::xsub_t::xattach_pipe (pipe_t *pipe_, const blob_t &peer_identity_)
+void zmq::xsub_t::xattach_pipe (pipe_t *pipe_)
 {
     zmq_assert (pipe_);
     fq.attach (pipe_);
diff --git a/src/xsub.hpp b/src/xsub.hpp
index 03b3178..ea59cdb 100644
--- a/src/xsub.hpp
+++ b/src/xsub.hpp
@@ -41,7 +41,7 @@ namespace zmq
     protected:
 
         //  Overloads of functions from socket_base_t.
-        void xattach_pipe (class pipe_t *pipe_, const blob_t &peer_identity_);
+        void xattach_pipe (class pipe_t *pipe_);
         int xsend (class msg_t *msg_, int flags_);
         bool xhas_out ();
         int xrecv (class msg_t *msg_, int flags_);
diff --git a/src/zmq_connecter.cpp b/src/zmq_connecter.cpp
index ca9bb77..0512c3c 100644
--- a/src/zmq_connecter.cpp
+++ b/src/zmq_connecter.cpp
@@ -30,7 +30,6 @@
 
 #include "zmq_connecter.hpp"
 #include "zmq_engine.hpp"
-#include "zmq_init.hpp"
 #include "io_thread.hpp"
 #include "err.hpp"
 
@@ -86,16 +85,12 @@ void zmq::zmq_connecter_t::out_event ()
         return;
     }
 
-    //  Choose I/O thread to run connecter in. Given that we are already
-    //  running in an I/O thread, there must be at least one available.
-    io_thread_t *io_thread = choose_io_thread (options.affinity);
-    zmq_assert (io_thread);
+    //  Create the engine object for this connection.
+    zmq_engine_t *engine = new (std::nothrow) zmq_engine_t (fd, options);
+    alloc_assert (engine);
 
-    //  Create an init object. 
-    zmq_init_t *init = new (std::nothrow) zmq_init_t (io_thread, NULL,
-        session, fd, options);
-    alloc_assert (init);
-    launch_sibling (init);
+    //  Attach the engine to the corresponding session object.
+    send_attach (session, engine);
 
     //  Shut the connecter down.
     terminate ();
diff --git a/src/zmq_init.cpp b/src/zmq_init.cpp
deleted file mode 100644
index 8352719..0000000
--- a/src/zmq_init.cpp
+++ /dev/null
@@ -1,233 +0,0 @@
-/*
-    Copyright (c) 2007-2011 iMatix Corporation
-    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
-
-    This file is part of 0MQ.
-
-    0MQ is free software; you can redistribute it and/or modify it under
-    the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 3 of the License, or
-    (at your option) any later version.
-
-    0MQ is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#include <string.h>
-
-#include "zmq_init.hpp"
-#include "transient_session.hpp"
-#include "named_session.hpp"
-#include "socket_base.hpp"
-#include "zmq_engine.hpp"
-#include "io_thread.hpp"
-#include "session.hpp"
-#include "uuid.hpp"
-#include "blob.hpp"
-#include "wire.hpp"
-#include "err.hpp"
-
-zmq::zmq_init_t::zmq_init_t (io_thread_t *io_thread_,
-      socket_base_t *socket_, session_t *session_, fd_t fd_,
-      const options_t &options_) :
-    own_t (io_thread_, options_),
-    ephemeral_engine (NULL),
-    received (false),
-    socket (socket_),
-    session (session_),
-    io_thread (io_thread_)
-{
-    //  Create the engine object for this connection.
-    engine = new (std::nothrow) zmq_engine_t (fd_, options);
-    alloc_assert (engine);
-
-    //  Generate an unique identity.
-    peer_identity.resize (17);
-    peer_identity [0] = 0;
-    generate_uuid (&peer_identity [1]);
-
-    //  Create a list of messages to send on connection initialisation.
-    if (!options.identity.empty ()) {
-        msg_t msg;
-        int rc = msg.init_size (options.identity.size ());
-        errno_assert (rc == 0);
-        memcpy (msg.data () , options.identity.data (), msg.size ());
-        to_send.push_back (msg);
-    }
-    else {
-        msg_t msg;
-        int rc = msg.init ();
-        errno_assert (rc == 0);
-        to_send.push_back (msg);
-    }
-}
-
-zmq::zmq_init_t::~zmq_init_t ()
-{
-    if (engine)
-        engine->terminate ();
-
-    //  If there are unsent props still queued deallocate them.
-    for (to_send_t::iterator it = to_send.begin (); it != to_send.end ();
-          ++it) {
-        int rc = it->close ();
-        errno_assert (rc == 0);
-    }
-    to_send.clear ();
-}
-
-bool zmq::zmq_init_t::read (msg_t *msg_)
-{
-    //  If the identity was already sent, do nothing.
-    if (to_send.empty ())
-        return false;
-
-    //  Pass next property to the engine.
-    *msg_ = to_send.front ();
-    to_send.erase (to_send.begin ());
-
-    //  Try finalize initialization.
-    finalise_initialisation ();
-
-    return true;
-}
-
-bool zmq::zmq_init_t::write (msg_t *msg_)
-{
-    //  If identity was already received, we are not interested
-    //  in subsequent messages.
-    if (received)
-        return false;
-
-    //  Retrieve the peer's identity, if any.
-    zmq_assert (!(msg_->flags () & msg_t::more));
-    size_t size = msg_->size ();
-    if (size) {
-        unsigned char *data = (unsigned char*) msg_->data ();
-        peer_identity.assign (data, size);
-    }
-
-    received = true;
-    finalise_initialisation ();
-
-    return true;
-}
-
-void zmq::zmq_init_t::flush ()
-{
-    //  Check if there's anything to flush.
-    if (!received)
-        return;
-
-    //  Initialization is done, dispatch engine.
-    if (ephemeral_engine)
-        dispatch_engine ();
-}
-
-void zmq::zmq_init_t::detach ()
-{
-    //  This function is called by engine when disconnection occurs.
-
-    //  If there is an associated session, send it a null engine to let it know
-    //  that connection process was unsuccesful.
-    if (session)
-        send_attach (session, NULL, blob_t (), true);
-
-    //  The engine will destroy itself, so let's just drop the pointer here and
-    //  start termination of the init object.
-    engine = NULL;
-    terminate ();
-}
-
-void zmq::zmq_init_t::process_plug ()
-{
-    zmq_assert (engine);
-    engine->plug (io_thread, this);
-}
-
-void zmq::zmq_init_t::process_unplug ()
-{
-    if (engine)
-        engine->unplug ();
-}
-
-void zmq::zmq_init_t::finalise_initialisation ()
-{
-     //  Unplug and prepare to dispatch engine.
-     if (to_send.empty () && received) {
-        ephemeral_engine = engine;
-        engine = NULL;
-        ephemeral_engine->unplug ();
-        return;
-    }
-}
-
-void zmq::zmq_init_t::dispatch_engine ()
-{
-    if (to_send.empty () && received) {
-
-        //  Engine must be detached.
-        zmq_assert (!engine);
-        zmq_assert (ephemeral_engine);
-
-        //  If we know what session we belong to, it's easy, just send the
-        //  engine to that session and destroy the init object. Note that we
-        //  know about the session only if this object is owned by it. Thus,
-        //  lifetime of this object in contained in the lifetime of the session
-        //  so the pointer cannot become invalid without notice.
-        if (session) {
-            send_attach (session, ephemeral_engine, peer_identity, true);
-            terminate ();
-            return;
-        }
-
-        //  All the cases below are listener-based. Therefore we need the socket
-        //  reference so that new sessions can bind to that socket.
-        zmq_assert (socket);
-
-        //  We have no associated session. If the peer has no identity we'll
-        //  create a transient session for the connection. Note that
-        //  seqnum is incremented to account for attach command before the
-        //  session is launched. That way we are sure it won't terminate before
-        //  being attached.
-        if (peer_identity [0] == 0) {
-            session = new (std::nothrow) transient_session_t (io_thread,
-                socket, options);
-            alloc_assert (session);
-            session->inc_seqnum ();
-            launch_sibling (session);
-            send_attach (session, ephemeral_engine, peer_identity, false);
-            terminate ();
-            return;
-        }
-        
-        //  Try to find the session corresponding to the peer's identity.
-        //  If found, send the engine to that session and destroy this object.
-        //  Note that session's seqnum is incremented by find_session rather
-        //  than by send_attach.
-        session = socket->find_session (peer_identity);
-        if (session) {
-            send_attach (session, ephemeral_engine, peer_identity, false);
-            terminate ();
-            return;
-        }
-
-        //  There's no such named session. We have to create one. Note that
-        //  seqnum is incremented to account for attach command before the
-        //  session is launched. That way we are sure it won't terminate before
-        //  being attached.
-        session = new (std::nothrow) named_session_t (io_thread, socket,
-            options, peer_identity);
-        alloc_assert (session);
-        session->inc_seqnum ();
-        launch_sibling (session);
-        send_attach (session, ephemeral_engine, peer_identity, false);
-        terminate ();
-        return;
-    }
-}
diff --git a/src/zmq_init.hpp b/src/zmq_init.hpp
deleted file mode 100644
index e220d2b..0000000
--- a/src/zmq_init.hpp
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
-    Copyright (c) 2007-2011 iMatix Corporation
-    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
-
-    This file is part of 0MQ.
-
-    0MQ is free software; you can redistribute it and/or modify it under
-    the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 3 of the License, or
-    (at your option) any later version.
-
-    0MQ is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#ifndef __ZMQ_ZMQ_INIT_HPP_INCLUDED__
-#define __ZMQ_ZMQ_INIT_HPP_INCLUDED__
-
-#include <vector>
-
-#include "i_engine.hpp"
-#include "stdint.hpp"
-#include "blob.hpp"
-#include "msg.hpp"
-#include "own.hpp"
-#include "fd.hpp"
-
-namespace zmq
-{
-
-    //  The class handles initialisation phase of 0MQ wire-level protocol.
-
-    class zmq_init_t :
-        public own_t,
-        public i_engine_sink
-    {
-    public:
-
-        zmq_init_t (class io_thread_t *io_thread_, class socket_base_t *socket_,
-            class session_t *session_, fd_t fd_, const options_t &options_);
-        ~zmq_init_t ();
-
-    private:
-
-        void finalise_initialisation ();
-        void dispatch_engine ();
-
-        //  i_engine_sink interface implementation.
-        bool read (class msg_t *msg_);
-        bool write (class msg_t *msg_);
-        void flush ();
-        void detach ();
-
-        //  Handlers for incoming commands.
-        void process_plug ();
-        void process_unplug ();
-
-        //  Associated wire-protocol engine.
-        i_engine *engine;
-
-        //  Detached transient engine.
-        i_engine *ephemeral_engine;
-
-        //  List of messages to send to the peer during the connection
-        //  initiation phase.
-        typedef std::vector <msg_t> to_send_t;
-        to_send_t to_send;
-
-        //  True if peer's identity was already received.
-        bool received;
-
-        //  Socket the object belongs to.
-        class socket_base_t *socket;
-
-        //  Reference to the session the init object belongs to.
-        //  If the associated session is unknown and should be found
-        //  depending on peer identity this value is NULL.
-        class session_t *session;
-
-        //  Identity of the peer socket.
-        blob_t peer_identity;
-
-        //  I/O thread the object is living in. It will be used to plug
-        //  the engine into the same I/O thread.
-        class io_thread_t *io_thread;
-
-        zmq_init_t (const zmq_init_t&);
-        const zmq_init_t &operator = (const zmq_init_t&);
-    };
-
-}
-
-#endif
diff --git a/src/zmq_listener.cpp b/src/zmq_listener.cpp
index e3f3bd8..2d5e7bb 100644
--- a/src/zmq_listener.cpp
+++ b/src/zmq_listener.cpp
@@ -21,7 +21,8 @@
 #include <new>
 
 #include "zmq_listener.hpp"
-#include "zmq_init.hpp"
+#include "transient_session.hpp"
+#include "zmq_engine.hpp"
 #include "io_thread.hpp"
 #include "err.hpp"
 
@@ -63,16 +64,21 @@ void zmq::zmq_listener_t::in_event ()
     //  TODO: Handle specific errors like ENFILE/EMFILE etc.
     if (fd == retired_fd)
         return;
+    //  Create the engine object for this connection.
+    zmq_engine_t *engine = new (std::nothrow) zmq_engine_t (fd, options);
+    alloc_assert (engine);
 
     //  Choose I/O thread to run connecter in. Given that we are already
     //  running in an I/O thread, there must be at least one available.
     io_thread_t *io_thread = choose_io_thread (options.affinity);
     zmq_assert (io_thread);
 
-    //  Create and launch an init object. 
-    zmq_init_t *init = new (std::nothrow) zmq_init_t (io_thread, socket,
-        NULL, fd, options);
-    alloc_assert (init);
-    launch_child (init);
+    //  Create and launch a session object. 
+    transient_session_t *session = new (std::nothrow)
+        transient_session_t (io_thread, socket, options);
+    alloc_assert (session);
+    session->inc_seqnum ();
+    launch_child (session);
+    send_attach (session, engine, false);
 }