Added ZMQ_STREAM socket type

- designed for TCP clients and servers
- added HTTP client / server example in tests/test_stream.cpp
- same as ZMQ_ROUTER + ZMQ_ROUTER_RAW + ZMQ_ROUTER_MANDATORY
- includes b893ce set ZMQ_IDENTITY on outgoing connect
- deprecates ZMQ_ROUTER_RAW

.gitignore

@@ -50,7 +50,9 @@ tests/test_disconnect_inproc
 tests/test_ctx_options
 tests/test_iov
 tests/test_security
+tests/test_security_curve
 tests/test_probe_router
+tests/test_stream
 src/platform.hpp*
 src/stamp-h1
 perf/local_lat

doc/zmq_msg_send.txt

@@ -81,6 +81,8 @@ The operation was interrupted by delivery of a signal before the message was
 sent.
 *EFAULT*::
 Invalid message.
+*EHOSTUNREACH*::
+The message cannot be routed.
 
 
 EXAMPLE

doc/zmq_send.txt

@@ -70,6 +70,8 @@ The provided 'socket' was invalid.
 *EINTR*::
 The operation was interrupted by delivery of a signal before the message was
 sent.
+*EHOSTUNREACH*::
+The message cannot be routed.
 
 
 EXAMPLE

doc/zmq_sendmsg.txt

@@ -77,6 +77,8 @@ The operation was interrupted by delivery of a signal before the message was
 sent.
 *EFAULT*::
 Invalid message.
+*EHOSTUNREACH*::
+The message cannot be routed.
 
 
 EXAMPLE

doc/zmq_setsockopt.txt

@@ -417,6 +417,8 @@ When using raw mode, you cannot set explicit identities, and the ZMQ_MSGMORE
 flag is ignored when sending data messages. In raw mode you can close a specific
 connection by sending it a zero-length message (following the identity frame).
 
+NOTE: This option is deprecated, please use ZMQ_STREAM sockets instead.
+
 [horizontal]
 Option value type:: int
 Option value unit:: 0, 1

doc/zmq_socket.txt

@@ -323,6 +323,46 @@ Outgoing routing strategy:: N/A
 Action in mute state:: Block
 
 
+Native Pattern
+~~~~~~~~~~~~~~
+The native pattern is used for communicating with TCP peers and allows 
+asynchronous requests and replies in either direction.
+
+
+ZMQ_STREAM
+^^^^^^^^^^
+A socket of type 'ZMQ_STREAM' is used to send and receive TCP data from a 
+non-0MQ peer, when using the tcp:// transport. A 'ZMQ_STREAM' socket can 
+act as client and/or server, sending and/or receiving TCP data asynchronously.
+
+When receiving TCP data, a 'ZMQ_STREAM' socket shall prepend a message part
+containing the _identity_ of the originating peer to the message before passing 
+it to the application. Messages received are fair-queued from among all 
+connected peers. 
+
+When sending TCP data, a 'ZMQ_STREAM' socket shall remove the first part of the 
+message and use it to determine the _identity_ of the peer the message shall be 
+routed to, and unroutable messages shall cause an EHOSTUNREACH or EAGAIN error.
+
+To open a connection to a server, use the zmq_connect call, and then fetch the 
+socket identity using the ZMQ_IDENTITY zmq_getsockopt call.
+
+To close a specific client connection, as a server, send a zero-length message 
+following the identity frame.
+
+The ZMQ_MSGMORE flag is ignored on data frames. You must send one identity frame
+followed by one data frame.
+
+[horizontal]
+.Summary of ZMQ_STREAM characteristics
+Compatible peer sockets:: none.
+Direction:: Bidirectional
+Send/receive pattern:: Unrestricted
+Outgoing routing strategy:: See text
+Incoming routing strategy:: Fair-queued
+Action in mute state:: EAGAIN
+
+
 RETURN VALUE
 ------------
 The _zmq_socket()_ function shall return an opaque handle to the newly created
@@ -357,5 +397,3 @@ AUTHORS
 -------
 This page was written by the 0MQ community. To make a change please
 read the 0MQ Contribution Policy at <http://www.zeromq.org/docs:contributing>.
-
-

include/zmq.h

@@ -227,6 +227,7 @@ ZMQ_EXPORT int zmq_msg_set (zmq_msg_t *msg, int option, int optval);
 #define ZMQ_PUSH 8
 #define ZMQ_XPUB 9
 #define ZMQ_XSUB 10
+#define ZMQ_STREAM 11
 
 /*  Deprecated aliases                                                        */
 #define ZMQ_XREQ ZMQ_DEALER

src/Makefile.am

@@ -72,6 +72,7 @@ libzmq_la_SOURCES = \
     signaler.hpp \
     socket_base.hpp \
     stdint.hpp \
+    stream.hpp \
     stream_engine.hpp \
     sub.hpp \
     tcp.hpp \
@@ -134,6 +135,7 @@ libzmq_la_SOURCES = \
     session_base.cpp \
     signaler.cpp \
     socket_base.cpp \
+    stream.cpp \
     stream_engine.cpp \
     sub.cpp \
     tcp.cpp \

src/mechanism.cpp

@@ -51,8 +51,8 @@ const char *zmq::mechanism_t::socket_type_string (int socket_type) const
 {
     static const char *names [] = {"PAIR", "PUB", "SUB", "REQ", "REP",
                                    "DEALER", "ROUTER", "PULL", "PUSH",
-                                   "XPUB", "XSUB"};
-    zmq_assert (socket_type >= 0 && socket_type <= 10);
+                                   "XPUB", "XSUB", "STREAM"};
+    zmq_assert (socket_type >= ZMQ_PAIR && socket_type <= ZMQ_STREAM);
     return names [socket_type];
 }
 

src/router.cpp

@@ -33,7 +33,8 @@ zmq::router_t::router_t (class ctx_t *parent_, uint32_t tid_, int sid_) :
     more_out (false),
     next_peer_id (generate_random ()),
     mandatory (false),
-    raw_sock (false),
+    //  raw_sock functionality in ROUTER is deprecated
+    raw_sock (false),       
     probe_router (false)
 {
     options.type = ZMQ_ROUTER;
@@ -272,7 +273,6 @@ int zmq::router_t::xrecv (msg_t *msg_)
     //  It's possible that we receive peer's identity. That happens
     //  after reconnection. The current implementation assumes that
     //  the peer always uses the same identity.
-    //  TODO: handle the situation when the peer changes its identity.
     while (rc == 0 && msg_->is_identity ())
         rc = fq.recvpipe (msg_, &pipe);
 
@@ -372,9 +372,6 @@ bool zmq::router_t::identify_peer (pipe_t *pipe_)
         buf [0] = 0;
         put_uint32 (buf + 1, next_peer_id++);
         identity = blob_t (buf, sizeof buf);
-        unsigned int i = 0;  // Store identity to allow use of raw socket as client
-        for (blob_t::iterator it = identity.begin(); it != identity.end(); it++) options.identity[i++] = *it;
-        options.identity_size = i;
     }
     else {
         msg.init ();

src/session_base.cpp

@@ -40,6 +40,7 @@
 #include "push.hpp"
 #include "pull.hpp"
 #include "pair.hpp"
+#include "stream.hpp"
 
 zmq::session_base_t *zmq::session_base_t::create (class io_thread_t *io_thread_,
     bool connect_, class socket_base_t *socket_, const options_t &options_,
@@ -91,6 +92,10 @@ zmq::session_base_t *zmq::session_base_t::create (class io_thread_t *io_thread_,
         s = new (std::nothrow) pair_session_t (io_thread_, connect_,
             socket_, options_, addr_);
         break;
+    case ZMQ_STREAM:
+        s = new (std::nothrow) stream_session_t (io_thread_, connect_,
+            socket_, options_, addr_);
+        break;
     default:
         errno = EINVAL;
         return NULL;

src/socket_base.cpp

@@ -67,6 +67,7 @@
 #include "router.hpp"
 #include "xpub.hpp"
 #include "xsub.hpp"
+#include "stream.hpp"
 
 bool zmq::socket_base_t::check_tag ()
 {
@@ -112,6 +113,9 @@ zmq::socket_base_t *zmq::socket_base_t::create (int type_, class ctx_t *parent_,
     case ZMQ_XSUB:
         s = new (std::nothrow) xsub_t (parent_, tid_, sid_);
         break;
+    case ZMQ_STREAM:
+        s = new (std::nothrow) stream_t (parent_, tid_, sid_);
+        break;
     default:
         errno = EINVAL;
         return NULL;

src/stream.cpp

+/*
+    Copyright (c) 2007-2013 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 "stream.hpp"
+#include "pipe.hpp"
+#include "wire.hpp"
+#include "random.hpp"
+#include "likely.hpp"
+#include "err.hpp"
+
+zmq::stream_t::stream_t (class ctx_t *parent_, uint32_t tid_, int sid_) :
+    socket_base_t (parent_, tid_, sid_),
+    prefetched (false),
+    identity_sent (false),
+    more_in (false),
+    current_out (NULL),
+    more_out (false),
+    next_peer_id (generate_random ())
+{
+    options.type = ZMQ_STREAM;
+    options.recv_identity = true;
+    options.raw_sock = true;
+
+    prefetched_id.init ();
+    prefetched_msg.init ();
+}
+
+zmq::stream_t::~stream_t ()
+{
+    zmq_assert (anonymous_pipes.empty ());;
+    zmq_assert (outpipes.empty ());
+    prefetched_id.close ();
+    prefetched_msg.close ();
+}
+
+void zmq::stream_t::xattach_pipe (pipe_t *pipe_, bool icanhasall_)
+{
+    // icanhasall_ is unused
+    (void)icanhasall_;
+
+    zmq_assert (pipe_);
+
+    bool identity_ok = identify_peer (pipe_);
+    if (identity_ok)
+        fq.attach (pipe_);
+    else
+        anonymous_pipes.insert (pipe_);
+}
+
+void zmq::stream_t::xpipe_terminated (pipe_t *pipe_)
+{
+    std::set <pipe_t*>::iterator it = anonymous_pipes.find (pipe_);
+    if (it != anonymous_pipes.end ())
+        anonymous_pipes.erase (it);
+    else {
+        outpipes_t::iterator it = outpipes.find (pipe_->get_identity ());
+        zmq_assert (it != outpipes.end ());
+        outpipes.erase (it);
+        fq.pipe_terminated (pipe_);
+        if (pipe_ == current_out)
+            current_out = NULL;
+    }
+}
+
+void zmq::stream_t::xread_activated (pipe_t *pipe_)
+{
+    std::set <pipe_t*>::iterator it = anonymous_pipes.find (pipe_);
+    if (it == anonymous_pipes.end ())
+        fq.activated (pipe_);
+    else {
+        bool identity_ok = identify_peer (pipe_);
+        if (identity_ok) {
+            anonymous_pipes.erase (it);
+            fq.attach (pipe_);
+        }
+    }
+}
+
+void zmq::stream_t::xwrite_activated (pipe_t *pipe_)
+{
+    outpipes_t::iterator it;
+    for (it = outpipes.begin (); it != outpipes.end (); ++it)
+        if (it->second.pipe == pipe_)
+            break;
+
+    zmq_assert (it != outpipes.end ());
+    zmq_assert (!it->second.active);
+    it->second.active = true;
+}
+
+int zmq::stream_t::xsend (msg_t *msg_)
+{
+    //  If this is the first part of the message it's the ID of the
+    //  peer to send the message to.
+    if (!more_out) {
+        zmq_assert (!current_out);
+
+        //  If we have malformed message (prefix with no subsequent message)
+        //  then just silently ignore it.
+        //  TODO: The connections should be killed instead.
+        if (msg_->flags () & msg_t::more) {
+
+            more_out = true;
+
+            //  Find the pipe associated with the identity stored in the prefix.
+            //  If there's no such pipe return an error
+            blob_t identity ((unsigned char*) msg_->data (), msg_->size ());
+            outpipes_t::iterator it = outpipes.find (identity);
+
+            if (it != outpipes.end ()) {
+                current_out = it->second.pipe;
+                if (!current_out->check_write ()) {
+                    it->second.active = false;
+                    current_out = NULL;
+                    more_out = false;
+                    errno = EAGAIN;
+                    return -1;
+                }
+            }
+            else {
+                more_out = false;
+                errno = EHOSTUNREACH;
+                return -1;
+            }
+        }
+
+        int rc = msg_->close ();
+        errno_assert (rc == 0);
+        rc = msg_->init ();
+        errno_assert (rc == 0);
+        return 0;
+    }
+
+    //  Ignore the MORE flag 
+    msg_->reset_flags (msg_t::more);
+
+    //  Check whether this is the last part of the message.
+    more_out = msg_->flags () & msg_t::more ? true : false;
+
+    //  Push the message into the pipe. If there's no out pipe, just drop it.
+    if (current_out) {
+
+        // Close the remote connection if user has asked to do so
+        // by sending zero length message.
+        // Pending messages in the pipe will be dropped (on receiving term- ack)
+        if (msg_->size() == 0) {
+            current_out->terminate (false);
+            int rc = msg_->close ();
+            errno_assert (rc == 0);
+            current_out = NULL;
+            return 0;
+        }
+        bool ok = current_out->write (msg_);
+        if (unlikely (!ok))
+            current_out = NULL;
+        else
+        if (!more_out) {
+            current_out->flush ();
+            current_out = NULL;
+        }
+    }
+    else {
+        int rc = msg_->close ();
+        errno_assert (rc == 0);
+    }
+
+    //  Detach the message from the data buffer.
+    int rc = msg_->init ();
+    errno_assert (rc == 0);
+
+    return 0;
+}
+
+int zmq::stream_t::xrecv (msg_t *msg_)
+{
+    if (prefetched) {
+        if (!identity_sent) {
+            int rc = msg_->move (prefetched_id);
+            errno_assert (rc == 0);
+            identity_sent = true;
+        }
+        else {
+            int rc = msg_->move (prefetched_msg);
+            errno_assert (rc == 0);
+            prefetched = false;
+        }
+        more_in = msg_->flags () & msg_t::more ? true : false;
+        return 0;
+    }
+
+    pipe_t *pipe = NULL;
+    int rc = fq.recvpipe (msg_, &pipe);
+
+    //  It's possible that we receive peer's identity. That happens
+    //  after reconnection. The current implementation assumes that
+    //  the peer always uses the same identity.
+    //  TODO: handle the situation when the peer changes its identity.
+    while (rc == 0 && msg_->is_identity ())
+        rc = fq.recvpipe (msg_, &pipe);
+
+    if (rc != 0)
+        return -1;
+
+    zmq_assert (pipe != NULL);
+
+    //  If we are in the middle of reading a message, just return the next part.
+    if (more_in)
+        more_in = msg_->flags () & msg_t::more ? true : false;
+    else {
+        //  We are at the beginning of a message.
+        //  Keep the message part we have in the prefetch buffer
+        //  and return the ID of the peer instead.
+        rc = prefetched_msg.move (*msg_);
+        errno_assert (rc == 0);
+        prefetched = true;
+
+        blob_t identity = pipe->get_identity ();
+        rc = msg_->init_size (identity.size ());
+        errno_assert (rc == 0);
+        memcpy (msg_->data (), identity.data (), identity.size ());
+        msg_->set_flags (msg_t::more);
+        identity_sent = true;
+    }
+
+    return 0;
+}
+
+int zmq::stream_t::rollback (void)
+{
+    if (current_out) {
+        current_out->rollback ();
+        current_out = NULL;
+        more_out = false;
+    }
+    return 0;
+}
+
+bool zmq::stream_t::xhas_in ()
+{
+    //  If we are in the middle of reading the messages, there are
+    //  definitely more parts available.
+    if (more_in)
+        return true;
+
+    //  We may already have a message pre-fetched.
+    if (prefetched)
+        return true;
+
+    //  Try to read the next message.
+    //  The message, if read, is kept in the pre-fetch buffer.
+    pipe_t *pipe = NULL;
+    int rc = fq.recvpipe (&prefetched_msg, &pipe);
+
+    //  It's possible that we receive peer's identity. That happens
+    //  after reconnection. The current implementation assumes that
+    //  the peer always uses the same identity.
+    while (rc == 0 && prefetched_msg.is_identity ())
+        rc = fq.recvpipe (&prefetched_msg, &pipe);
+
+    if (rc != 0)
+        return false;
+
+    zmq_assert (pipe != NULL);
+
+    blob_t identity = pipe->get_identity ();
+    rc = prefetched_id.init_size (identity.size ());
+    errno_assert (rc == 0);
+    memcpy (prefetched_id.data (), identity.data (), identity.size ());
+    prefetched_id.set_flags (msg_t::more);
+
+    prefetched = true;
+    identity_sent = false;
+
+    return true;
+}
+
+bool zmq::stream_t::xhas_out ()
+{
+    //  In theory, ROUTER socket is always ready for writing. Whether actual
+    //  attempt to write succeeds depends on which pipe the message is going
+    //  to be routed to.
+    return true;
+}
+
+bool zmq::stream_t::identify_peer (pipe_t *pipe_)
+{
+    blob_t identity;
+    bool ok;
+
+    //  Always assign identity for raw-socket
+    unsigned char buffer [5];
+    buffer [0] = 0;
+    put_uint32 (buffer + 1, next_peer_id++);
+    identity = blob_t (buffer, sizeof buffer);
+    unsigned int i = 0;  // Store identity to allow use of raw socket as client
+    for (blob_t::iterator it = identity.begin(); it != identity.end(); it++)
+        options.identity[i++] = *it;
+    options.identity_size = i;
+
+    pipe_->set_identity (identity);
+    //  Add the record into output pipes lookup table
+    outpipe_t outpipe = {pipe_, true};
+    ok = outpipes.insert (outpipes_t::value_type (identity, outpipe)).second;
+    zmq_assert (ok);
+
+    return true;
+}
+
+zmq::stream_session_t::stream_session_t (io_thread_t *io_thread_, bool connect_,
+      socket_base_t *socket_, const options_t &options_,
+      const address_t *addr_) :
+    session_base_t (io_thread_, connect_, socket_, options_, addr_)
+{
+}
+
+zmq::stream_session_t::~stream_session_t ()
+{
+}
+

src/stream.hpp

+/*
+    Copyright (c) 2007-2013 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_STREAM_HPP_INCLUDED__
+#define __ZMQ_STREAM_HPP_INCLUDED__
+
+#include <map>
+
+#include "router.hpp"
+
+namespace zmq
+{
+
+    class ctx_t;
+    class pipe_t;
+
+    class stream_t : 
+        public socket_base_t
+    {
+    public:
+
+        stream_t (zmq::ctx_t *parent_, uint32_t tid_, int sid);
+        ~stream_t ();
+
+        //  Overloads of functions from socket_base_t.
+        void xattach_pipe (zmq::pipe_t *pipe_, bool icanhasall_);
+        int xsend (zmq::msg_t *msg_);
+        int xrecv (zmq::msg_t *msg_);
+        bool xhas_in ();
+        bool xhas_out ();
+        void xread_activated (zmq::pipe_t *pipe_);
+        void xwrite_activated (zmq::pipe_t *pipe_);
+        void xpipe_terminated (zmq::pipe_t *pipe_);
+
+    protected:
+
+        //  Rollback any message parts that were sent but not yet flushed.
+        int rollback ();
+
+    private:
+        //  Receive peer id and update lookup map
+        bool identify_peer (pipe_t *pipe_);
+
+        //  Fair queueing object for inbound pipes.
+        fq_t fq;
+
+        //  True iff there is a message held in the pre-fetch buffer.
+        bool prefetched;
+
+        //  If true, the receiver got the message part with
+        //  the peer's identity.
+        bool identity_sent;
+
+        //  Holds the prefetched identity.
+        msg_t prefetched_id;
+
+        //  Holds the prefetched message.
+        msg_t prefetched_msg;
+
+        //  If true, more incoming message parts are expected.
+        bool more_in;
+
+        struct outpipe_t
+        {
+            zmq::pipe_t *pipe;
+            bool active;
+        };
+
+        //  We keep a set of pipes that have not been identified yet.
+        std::set <pipe_t*> anonymous_pipes;
+
+        //  Outbound pipes indexed by the peer IDs.
+        typedef std::map <blob_t, outpipe_t> outpipes_t;
+        outpipes_t outpipes;
+
+        //  The pipe we are currently writing to.
+        zmq::pipe_t *current_out;
+
+        //  If true, more outgoing message parts are expected.
+        bool more_out;
+
+        //  Peer ID are generated. It's a simple increment and wrap-over
+        //  algorithm. This value is the next ID to use (if not used already).
+        uint32_t next_peer_id;
+
+        // If true, report EAGAIN to the caller instead of silently dropping 
+        // the message targeting an unknown peer.
+        bool mandatory;
+
+        stream_t (const stream_t&);
+        const stream_t &operator = (const stream_t&);
+    };
+
+    class stream_session_t : public session_base_t
+    {
+    public:
+
+        stream_session_t (zmq::io_thread_t *io_thread_, bool connect_,
+            socket_base_t *socket_, const options_t &options_,
+            const address_t *addr_);
+        ~stream_session_t ();
+
+    private:
+
+        stream_session_t (const stream_session_t&);
+        const stream_session_t &operator = (const stream_session_t&);
+    };
+
+}
+
+#endif

tests/Makefile.am

@@ -19,7 +19,7 @@ noinst_PROGRAMS = test_pair_inproc \
                   test_monitor \
                   test_router_mandatory \
                   test_probe_router \
-                  test_raw_sock \
+                  test_stream \
                   test_disconnect_inproc \
                   test_ctx_options \
                   test_security \
@@ -49,7 +49,7 @@ test_term_endpoint_SOURCES = test_term_endpoint.cpp
 test_monitor_SOURCES = test_monitor.cpp
 test_router_mandatory_SOURCES = test_router_mandatory.cpp
 test_probe_router_SOURCES = test_probe_router.cpp
-test_raw_sock_SOURCES = test_raw_sock.cpp
+test_stream_SOURCES = test_stream.cpp
 test_disconnect_inproc_SOURCES = test_disconnect_inproc.cpp
 test_ctx_options_SOURCES = test_ctx_options.cpp
 test_iov_SOURCES = test_iov.cpp
@@ -62,4 +62,9 @@ test_reqrep_ipc_SOURCES = test_reqrep_ipc.cpp testutil.hpp
 test_timeo_SOURCES = test_timeo.cpp
 endif
 
+#  Deprecated test cases
+noinst_PROGRAMS += test_raw_sock
+test_raw_sock_SOURCES = test_raw_sock.cpp
+
+#  Run the test cases
 TESTS = $(noinst_PROGRAMS)

tests/test_stream.cpp

+/*
+    Copyright (c) 2007-2013 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 "../include/zmq.h"
+#include <string.h>
+#include <stdbool.h>
+#undef NDEBUG
+#include <assert.h>
+
+//  ZMTP protocol greeting structure
+
+typedef unsigned char byte;
+typedef struct {
+    byte signature [10];    //  0xFF 8*0x00 0x7F
+    byte version [2];       //  0x03 0x00 for ZMTP/3.0
+    byte mechanism [20];    //  "NULL"
+    byte as_server;
+    byte filler [31];
+} zmtp_greeting_t;
+
+#define ZMTP_DEALER  5      //  Socket type constants
+
+//  This is a greeting matching what 0MQ will send us; note the
+//  8-byte size is set to 1 for backwards compatibility
+
+static zmtp_greeting_t greeting
+    = { { 0xFF, 0, 0, 0, 0, 0, 0, 0, 1, 0x7F }, {3, 0}, { 'N', 'U', 'L', 'L'} };
+
+static void
+test_stream_to_dealer (void) 
+{
+    int rc;
+
+    //  Set up our context and sockets
+    void *ctx = zmq_ctx_new ();
+    assert (ctx);
+
+    //  We'll be using this socket in raw mode
+    void *stream = zmq_socket (ctx, ZMQ_STREAM);
+    assert (stream);
+
+    int zero = 0;
+    rc = zmq_setsockopt (stream, ZMQ_LINGER, &zero, sizeof (zero));
+    assert (rc == 0);
+    rc = zmq_bind (stream, "tcp://*:5556");
+    assert (rc == 0);
+
+    //  We'll be using this socket as the other peer
+    void *dealer = zmq_socket (ctx, ZMQ_DEALER);
+    assert (dealer);
+    rc = zmq_setsockopt (dealer, ZMQ_LINGER, &zero, sizeof (zero));
+    assert (rc == 0);
+    rc = zmq_connect (dealer, "tcp://localhost:5556");
+
+    //  Send a message on the dealer socket
+    rc = zmq_send (dealer, "Hello", 5, 0);
+    assert (rc == 5);
+
+    //  First frame is identity
+    zmq_msg_t identity;
+    rc = zmq_msg_init (&identity);
+    assert (rc == 0);
+    rc = zmq_msg_recv (&identity, stream, 0);
+    assert (rc > 0);
+    assert (zmq_msg_more (&identity));
+
+    //  Second frame is greeting signature
+    byte buffer [255];
+    rc = zmq_recv (stream, buffer, 255, 0);
+    assert (rc == 10);
+    assert (memcmp (buffer, greeting.signature, 10) == 0);
+
+    //  Send our own protocol greeting
+    rc = zmq_msg_send (&identity, stream, ZMQ_SNDMORE);
+    assert (rc > 0);
+    rc = zmq_send (stream, &greeting, sizeof (greeting), 0);
+    assert (rc == sizeof (greeting));
+
+    //  Now we expect the data from the DEALER socket
+    //  First frame is, again, the identity of the connection
+    rc = zmq_msg_recv (&identity, stream, 0);
+    assert (rc > 0);
+    assert (zmq_msg_more (&identity));
+
+    //  Second frame contains the rest of greeting along with
+    //  the Ready command
+    rc = zmq_recv (stream, buffer, 255, 0);
+    assert (rc == 99);
+
+    //  First two bytes are major and minor version numbers.
+    assert (buffer [0] == 3);       //  ZMTP/3.0
+    assert (buffer [1] == 0);
+
+    //  Mechanism is "NULL"
+    assert (memcmp (buffer + 2, "NULL\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 22) == 0);
+    assert (memcmp (buffer + 54, "\0\53READY   ", 10) == 0);
+    assert (memcmp (buffer + 64, "\13Socket-Type\0\0\0\6DEALER", 22) == 0);
+    assert (memcmp (buffer + 86, "\10Identity\0\0\0\0", 13) == 0);
+
+    //  Announce we are ready
+    memcpy (buffer, "\0\53", 2);
+    memcpy (buffer + 2, "READY   ", 8);
+    memcpy (buffer + 10, "\13Socket-Type\0\0\0\6STREAM", 22);
+    memcpy (buffer + 32, "\10Identity\0\0\0\0", 13);
+
+    //  Send Ready command
+    rc = zmq_msg_send (&identity, stream, ZMQ_SNDMORE);
+    assert (rc > 0);
+    rc = zmq_send (stream, buffer, 45, 0);
+    assert (rc == 45);
+
+    //  Now we expect the data from the DEALER socket
+    //  First frame is, again, the identity of the connection
+    rc = zmq_msg_recv (&identity, stream, 0);
+    assert (rc > 0);
+    assert (zmq_msg_more (&identity));
+
+    //  Third frame contains Hello message from DEALER
+    rc = zmq_recv (stream, buffer, sizeof buffer, 0);
+    assert (rc == 7);
+
+    //  Then we have a 5-byte message "Hello"
+    assert (buffer [0] == 0);       //  Flags = 0
+    assert (buffer [1] == 5);       //  Size = 5
+    assert (memcmp (buffer + 2, "Hello", 5) == 0);
+
+    //  Send "World" back to DEALER
+    rc = zmq_msg_send (&identity, stream, ZMQ_SNDMORE);
+    assert (rc > 0);
+    byte world [] = { 0, 5, 'W', 'o', 'r', 'l', 'd' };
+    rc = zmq_send (stream, world, sizeof (world), 0);
+    assert (rc == sizeof (world));
+
+    //  Expect response on DEALER socket
+    rc = zmq_recv (dealer, buffer, 255, 0);
+    assert (rc == 5);
+    assert (memcmp (buffer, "World", 5) == 0);
+
+    rc = zmq_close (dealer);
+    assert (rc == 0);
+
+    rc = zmq_close (stream);
+    assert (rc == 0);
+
+    rc = zmq_ctx_term (ctx);
+    assert (rc == 0);
+}
+
+
+static void
+test_stream_to_stream (void)
+{
+    int rc;
+    //  Set-up our context and sockets
+    void *ctx = zmq_ctx_new ();
+    assert (ctx);
+    
+    void *server = zmq_socket (ctx, ZMQ_STREAM);
+    assert (server);
+    rc = zmq_bind (server, "tcp://*:8080");
+    assert (rc == 0);
+
+    void *client = zmq_socket (ctx, ZMQ_STREAM);
+    assert (client);
+    rc = zmq_connect (client, "tcp://localhost:8080");
+    assert (rc == 0);
+    //  It would be less surprising to get an empty message instead
+    //  of having to fetch the identity like this [PH 2013/06/27]
+    uint8_t id [256];
+    size_t id_size = 256;
+    rc = zmq_getsockopt (client, ZMQ_IDENTITY, id, &id_size);
+    assert (rc == 0);
+    
+    //  Sent HTTP request on client socket
+    //  First frame is server identity
+    rc = zmq_send (client, id, id_size, ZMQ_SNDMORE);
+    assert (rc == (int) id_size);
+    //  Second frame is HTTP GET request
+    rc = zmq_send (client, "GET /\n\n", 7, 0);
+    assert (rc == 7);
+    
+    //  Get HTTP request; ID frame and then request
+    id_size = zmq_recv (server, id, 256, 0);
+    assert (id_size > 0);
+    uint8_t buffer [256];
+    rc = zmq_recv (server, buffer, 256, 0);
+    assert (rc > 0);
+    assert (memcmp (buffer, "GET /\n\n", 7) == 0);
+    
+    //  Send reply back to client
+    char http_response [] =
+        "HTTP/1.0 200 OK\r\n" 
+        "Content-Type: text/plain\r\n" 
+        "\r\n" 
+        "Hello, World!";
+    zmq_send (server, id, id_size, ZMQ_SNDMORE);
+    zmq_send (server, http_response, sizeof (http_response), 0);
+
+    //  Get reply at client and check that it's complete
+    id_size = zmq_recv (client, id, 256, 0);
+    assert (id_size > 0);
+    rc = zmq_recv (client, buffer, 256, 0);
+    assert (rc == sizeof (http_response));
+    assert (memcmp (buffer, http_response, sizeof (http_response)) == 0);
+}
+
+
+int main (void)
+{
+    test_stream_to_dealer ();
+    test_stream_to_stream ();
+}
\ No newline at end of file