Add support for SOCKS proxies

This is still raw and experimental.
To connect through a SOCKS proxy, set ZMQ_SOCKS_PROXY socket option on
socket before issuing a connect call, e.g.:

    zmq_setsockopt (s, ZMQ_SOCKS_PROXY,
        "127.0.0.1:22222", strlen ("127.0.0.1:22222"));
    zmq_connect (s, "tcp://127.0.0.1:5555");

Known limitations:
- only SOCKS version 5 supported
- authentication not supported
- new option is still undocumented

include/zmq.h

@@ -302,6 +302,7 @@ ZMQ_EXPORT const char *zmq_msg_gets (zmq_msg_t *msg, const char *property);
 #define ZMQ_GSSAPI_PLAINTEXT 65
 #define ZMQ_HANDSHAKE_IVL 66
 #define ZMQ_IDENTITY_FD 67
+#define ZMQ_SOCKS_PROXY 68
 
 /*  Message options                                                           */
 #define ZMQ_MORE 1

src/Makefile.am

@@ -78,6 +78,8 @@ libzmq_la_SOURCES = \
     session_base.hpp \
     signaler.hpp \
     socket_base.hpp \
+    socks.hpp \
+    socks_connecter.hpp \
     stdint.hpp \
     stream.hpp \
     stream_engine.hpp \
@@ -149,6 +151,8 @@ libzmq_la_SOURCES = \
     session_base.cpp \
     signaler.cpp \
     socket_base.cpp \
+    socks.cpp \
+    socks_connecter.cpp \
     stream.cpp \
     stream_engine.cpp \
     sub.cpp \

src/options.cpp

@@ -206,6 +206,19 @@ int zmq::options_t::setsockopt (int option_, const void *optval_,
             }
             break;
 
+        case ZMQ_SOCKS_PROXY:
+            if (optval_ == NULL && optvallen_ == 0) {
+                socks_proxy_address.clear ();
+                return 0;
+            }
+            else
+            if (optval_ != NULL && optvallen_ > 0 ) {
+                socks_proxy_address =
+                    std::string ((const char *) optval_, optvallen_);
+                return 0;
+            }
+            break;
+
         case ZMQ_TCP_KEEPALIVE:
             if (is_int && (value == -1 || value == 0 || value == 1)) {
                 tcp_keepalive = value;
@@ -618,6 +631,14 @@ int zmq::options_t::getsockopt (int option_, void *optval_, size_t *optvallen_)
             }
             break;
 
+        case ZMQ_SOCKS_PROXY:
+            if (*optvallen_ >= socks_proxy_address.size () + 1) {
+                memcpy (optval_, socks_proxy_address.c_str (), socks_proxy_address.size () + 1);
+                *optvallen_ = socks_proxy_address.size () + 1;
+                return 0;
+            }
+            break;
+
         case ZMQ_TCP_KEEPALIVE:
             if (is_int) {
                 *value = tcp_keepalive;

src/options.hpp

@@ -114,6 +114,9 @@ namespace zmq
         // if true, router socket accepts non-zmq tcp connections
         bool raw_sock;
 
+        //  Addres of SOCKS proxy
+        std::string socks_proxy_address;
+
         //  TCP keep-alive settings.
         //  Defaults to -1 = do not change socket options
         int tcp_keepalive;

src/session_base.cpp

@@ -25,6 +25,7 @@
 #include "tcp_connecter.hpp"
 #include "ipc_connecter.hpp"
 #include "tipc_connecter.hpp"
+#include "socks_connecter.hpp"
 #include "pgm_sender.hpp"
 #include "pgm_receiver.hpp"
 #include "address.hpp"
@@ -497,10 +498,22 @@ void zmq::session_base_t::start_connecting (bool wait_)
     //  Create the connecter object.
 
     if (addr->protocol == "tcp") {
-        tcp_connecter_t *connecter = new (std::nothrow) tcp_connecter_t (
-            io_thread, this, options, addr, wait_);
-        alloc_assert (connecter);
-        launch_child (connecter);
+        if (options.socks_proxy_address != "") {
+            address_t *proxy_address = new (std::nothrow)
+                address_t ("tcp", options.socks_proxy_address);
+            alloc_assert (proxy_address);
+            socks_connecter_t *connecter =
+                new (std::nothrow) socks_connecter_t (
+                    io_thread, this, options, addr, proxy_address, wait_);
+            alloc_assert (connecter);
+            launch_child (connecter);
+        }
+        else {
+            tcp_connecter_t *connecter = new (std::nothrow)
+                tcp_connecter_t (io_thread, this, options, addr, wait_);
+            alloc_assert (connecter);
+            launch_child (connecter);
+        }
         return;
     }
 

src/socks.cpp

+/*
+    Copyright (c) 2007-2014 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 <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+
+#include "err.hpp"
+#include "platform.hpp"
+#include "socks.hpp"
+#include "tcp.hpp"
+
+zmq::socks_greeting_t::socks_greeting_t (uint8_t method_) :
+    num_methods (1)
+{
+    methods [0] = method_;
+}
+
+zmq::socks_greeting_t::socks_greeting_t (
+        uint8_t *methods_, size_t num_methods_)
+    : num_methods (num_methods_)
+{
+    zmq_assert (num_methods_ <= 255);
+
+    for (size_t i = 0; i < num_methods_; i++)
+        methods [i] = methods_ [i];
+}
+
+zmq::socks_greeting_encoder_t::socks_greeting_encoder_t ()
+    : bytes_encoded (0), bytes_written (0)
+{}
+
+void zmq::socks_greeting_encoder_t::encode (const socks_greeting_t &greeting_)
+{
+    uint8_t *ptr = buf;
+
+    *ptr++ = 0x05;
+    *ptr++ = greeting_.num_methods;
+    for (size_t i = 0; i < greeting_.num_methods; i++)
+        *ptr++ = greeting_.methods [i];
+
+    bytes_encoded = 2 + greeting_.num_methods;
+    bytes_written = 0;
+}
+
+int zmq::socks_greeting_encoder_t::output (fd_t fd_)
+{
+    const int rc = tcp_write (
+        fd_, buf + bytes_written, bytes_encoded - bytes_written);
+    if (rc > 0)
+        bytes_written += static_cast <size_t> (rc);
+    return rc;
+}
+
+bool zmq::socks_greeting_encoder_t::has_pending_data () const
+{
+    return bytes_written < bytes_encoded;
+}
+
+void zmq::socks_greeting_encoder_t::reset ()
+{
+    bytes_encoded = bytes_written = 0;
+}
+
+zmq::socks_choice_t::socks_choice_t (unsigned char method_)
+    : method (method_)
+{}
+
+zmq::socks_choice_decoder_t::socks_choice_decoder_t ()
+    : bytes_read (0)
+{}
+
+int zmq::socks_choice_decoder_t::input (fd_t fd_)
+{
+    zmq_assert (bytes_read < 2);
+    const int rc = tcp_read (fd_, buf + bytes_read, 2 - bytes_read);
+    if (rc > 0) {
+        bytes_read += static_cast <size_t> (rc);
+        if (buf [0] != 0x05)
+            return -1;
+    }
+    return rc;
+}
+
+bool zmq::socks_choice_decoder_t::message_ready () const
+{
+    return bytes_read == 2;
+}
+
+zmq::socks_choice_t zmq::socks_choice_decoder_t::decode ()
+{
+    zmq_assert (message_ready ());
+    return socks_choice_t (buf [1]);
+}
+
+void zmq::socks_choice_decoder_t::reset ()
+{
+    bytes_read = 0;
+}
+
+zmq::socks_request_t::socks_request_t (
+        uint8_t command_, std::string hostname_, uint16_t port_)
+    : command (command_), hostname (hostname_), port (port_)
+{}
+
+zmq::socks_request_encoder_t::socks_request_encoder_t ()
+    : bytes_encoded (0), bytes_written (0)
+{}
+
+void zmq::socks_request_encoder_t::encode (const socks_request_t &req)
+{
+    unsigned char *ptr = buf;
+    *ptr++ = 0x05;
+    *ptr++ = req.command;
+    *ptr++ = 0x00;
+
+#if defined ZMQ_HAVE_OPENVMS && defined __ia64 && __INITIAL_POINTER_SIZE == 64
+    __addrinfo64 hints, *res = NULL;
+#else
+    addrinfo hints, *res = NULL;
+#endif
+
+    memset (&hints, 0, sizeof hints);
+
+    //  Suppress potential DNS lookups.
+    hints.ai_flags = AI_NUMERICHOST;
+
+    const int rc = getaddrinfo (req.hostname.c_str (), NULL, &hints, &res);
+    if (rc == 0 && res->ai_family == AF_INET) {
+        struct sockaddr_in *sockaddr_in =
+            reinterpret_cast <struct sockaddr_in *> (res->ai_addr);
+        *ptr++ = 0x01;
+        memcpy (ptr, &sockaddr_in->sin_addr, 4);
+        ptr += 4;
+    }
+    else
+    if (rc == 0 && res->ai_family == AF_INET6) {
+        struct sockaddr_in6 *sockaddr_in6 =
+            reinterpret_cast <struct sockaddr_in6 *> (res->ai_addr);
+        *ptr++ = 0x04;
+        memcpy (ptr, &sockaddr_in6->sin6_addr, 16);
+        ptr += 16;
+    }
+    else {
+        *ptr++ = 0x03;
+        *ptr++ = req.hostname.size ();
+        memcpy (ptr, req.hostname.c_str (), req.hostname.size ());
+        ptr += req.hostname.size ();
+    }
+
+    if (rc == 0)
+        freeaddrinfo (res);
+
+    *ptr++ = req.port / 256;
+    *ptr++ = req.port % 256;
+
+    bytes_encoded = ptr - buf;
+    bytes_written = 0;
+}
+
+int zmq::socks_request_encoder_t::output (fd_t fd_)
+{
+    const int rc = tcp_write (
+        fd_, buf + bytes_written, bytes_encoded - bytes_written);
+    if (rc > 0)
+        bytes_written += static_cast <size_t> (rc);
+    return rc;
+}
+
+bool zmq::socks_request_encoder_t::has_pending_data () const
+{
+    return bytes_written < bytes_encoded;
+}
+
+void zmq::socks_request_encoder_t::reset ()
+{
+    bytes_encoded = bytes_written = 0;
+}
+
+zmq::socks_response_t::socks_response_t (
+        uint8_t response_code_, std::string address_, uint16_t port_)
+    : response_code (response_code_), address (address_), port (port_)
+{}
+
+zmq::socks_response_decoder_t::socks_response_decoder_t ()
+    : bytes_read (0)
+{}
+
+int zmq::socks_response_decoder_t::input (fd_t fd_)
+{
+    size_t n = 0;
+
+    if (bytes_read < 5)
+        n = 5 - bytes_read;
+    else {
+        const uint8_t atyp = buf [3];
+        zmq_assert (atyp == 0x01 || atyp == 0x03 || atyp == 0x04);
+        if (atyp == 0x01)
+            n = 3 + 2;
+        else
+        if (atyp == 0x03)
+            n = buf [4] + 2;
+        else
+        if (atyp == 0x04)
+            n = 15 + 2;
+    }
+    const int rc = tcp_read (fd_, buf + bytes_read, n);
+    if (rc > 0) {
+        bytes_read += static_cast <size_t> (rc);
+        if (buf [0] != 0x05)
+            return -1;
+        if (bytes_read >= 2)
+            if (buf [1] > 0x08)
+                return -1;
+        if (bytes_read >= 3)
+            if (buf [2] != 0x00)
+                return -1;
+        if (bytes_read >= 4) {
+            const uint8_t atyp = buf [3];
+            if (atyp != 0x01 && atyp != 0x03 && atyp != 0x04)
+                return -1;
+        }
+    }
+    return rc;
+}
+
+bool zmq::socks_response_decoder_t::message_ready () const
+{
+    if (bytes_read < 4)
+        return false;
+    else {
+        const uint8_t atyp = buf [3];
+        zmq_assert (atyp == 0x01 || atyp == 0x03 || atyp == 0x04);
+        if (atyp == 0x01)
+            return bytes_read == 10;
+        else
+        if (atyp == 0x03)
+            return bytes_read > 4 && bytes_read == 4 + 1 + buf [4] + 2u;
+        else
+            return bytes_read == 22;
+    }
+}
+
+zmq::socks_response_t zmq::socks_response_decoder_t::decode ()
+{
+    zmq_assert (message_ready ());
+    return socks_response_t (buf [1], "", 0);
+}
+
+void zmq::socks_response_decoder_t::reset ()
+{
+    bytes_read = 0;
+}

src/socks.hpp

+/*
+    Copyright (c) 2007-2014 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_SOCKS_HPP_INCLUDED__
+#define __ZMQ_SOCKS_HPP_INCLUDED__
+
+#include <string>
+#include "fd.hpp"
+#include "stdint.hpp"
+
+namespace zmq
+{
+
+    struct socks_greeting_t
+    {
+        socks_greeting_t (uint8_t method);
+        socks_greeting_t (uint8_t *methods_, size_t num_methods_);
+
+        uint8_t methods [255];
+        const size_t num_methods;
+    };
+
+    class socks_greeting_encoder_t
+    {
+        public:
+            socks_greeting_encoder_t ();
+            void encode (const socks_greeting_t &greeting_);
+            int output (fd_t fd_);
+            bool has_pending_data () const;
+            void reset ();
+
+        private:
+            size_t bytes_encoded;
+            size_t bytes_written;
+            uint8_t buf [2 + 255];
+    };
+
+    struct socks_choice_t
+    {
+        socks_choice_t (uint8_t method_);
+
+        uint8_t method;
+    };
+
+    class socks_choice_decoder_t
+    {
+        public:
+            socks_choice_decoder_t ();
+            int input (fd_t fd_);
+            bool message_ready () const;
+            socks_choice_t decode ();
+            void reset ();
+
+        private:
+            unsigned char buf [2];
+            size_t bytes_read;
+    };
+
+    struct socks_request_t
+    {
+        socks_request_t (
+            uint8_t command_, std::string hostname_, uint16_t port_);
+
+        const uint8_t command;
+        const std::string hostname;
+        const uint16_t port;
+    };
+
+    class socks_request_encoder_t
+    {
+        public:
+            socks_request_encoder_t ();
+            void encode (const socks_request_t &req);
+            int output (fd_t fd_);
+            bool has_pending_data () const;
+            void reset ();
+
+        private:
+            size_t bytes_encoded;
+            size_t bytes_written;
+            uint8_t buf [4 + 256 + 2];
+    };
+
+    struct socks_response_t
+    {
+        socks_response_t (
+            uint8_t response_code_, std::string address_, uint16_t port_);
+        uint8_t response_code;
+        std::string address;
+        uint16_t port;
+    };
+
+    class socks_response_decoder_t
+    {
+        public:
+            socks_response_decoder_t ();
+            int input (fd_t fd_);
+            bool message_ready () const;
+            socks_response_t decode ();
+            void reset ();
+
+        private:
+            uint8_t buf [4 + 256 + 2];
+            size_t bytes_read;
+    };
+
+}
+
+#endif

src/socks_connecter.hpp

+/*
+    Copyright (c) 2007-2014 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 __SOCKS_CONNECTER_HPP_INCLUDED__
+#define __SOCKS_CONNECTER_HPP_INCLUDED__
+
+#include "fd.hpp"
+#include "io_object.hpp"
+#include "own.hpp"
+#include "stdint.hpp"
+#include "../include/zmq.h"
+#include "socks.hpp"
+
+namespace zmq
+{
+
+    class io_thread_t;
+    class session_base_t;
+    struct address_t;
+
+    class socks_connecter_t : public own_t, public io_object_t
+    {
+    public:
+
+        //  If 'delayed_start' is true connecter first waits for a while,
+        //  then starts connection process.
+        socks_connecter_t (zmq::io_thread_t *io_thread_,
+            zmq::session_base_t *session_, const options_t &options_,
+            address_t *addr_, address_t *proxy_addr_,  bool delayed_start_);
+        ~socks_connecter_t ();
+
+    private:
+        enum {
+            unplugged,
+            waiting_for_reconnect_time,
+            waiting_for_proxy_connection,
+            sending_greeting,
+            waiting_for_choice,
+            sending_request,
+            waiting_for_response
+        };
+
+        //  ID of the timer used to delay the reconnection.
+        enum { reconnect_timer_id = 1 };
+
+        //  Method ID
+        enum { socks_no_auth_required = 0 };
+
+        //  Handlers for incoming commands.
+        virtual void process_plug ();
+        virtual void process_term (int linger_);
+
+        //  Handlers for I/O events.
+        virtual void in_event ();
+        virtual void out_event ();
+        virtual void timer_event (int id_);
+
+        //  Internal function to start the actual connection establishment.
+        void initiate_connect ();
+
+        int process_server_response (const socks_choice_t &response);
+        int process_server_response (const socks_response_t &response);
+
+        int parse_address (const std::string &address_,
+                std::string &hostname_, uint16_t &port_);
+
+        int connect_to_proxy ();
+
+        void error ();
+
+        //  Internal function to start reconnect timer
+        void start_timer ();
+
+        //  Internal function to return a reconnect backoff delay.
+        //  Will modify the current_reconnect_ivl used for next call
+        //  Returns the currently used interval
+        int get_new_reconnect_ivl ();
+
+        //  Open TCP connecting socket. Returns -1 in case of error,
+        //  0 if connect was successfull immediately. Returns -1 with
+        //  EAGAIN errno if async connect was launched.
+        int open ();
+
+        //  Close the connecting socket.
+        void close ();
+
+        //  Get the file descriptor of newly created connection. Returns
+        //  retired_fd if the connection was unsuccessfull.
+        int check_proxy_connection ();
+
+        socks_greeting_encoder_t greeting_encoder;
+        socks_choice_decoder_t choice_decoder;
+        socks_request_encoder_t request_encoder;
+        socks_response_decoder_t response_decoder;
+
+        //  Address to connect to. Owned by session_base_t.
+        address_t *addr;
+
+        address_t *proxy_addr;
+
+        int status;
+
+        //  Underlying socket.
+        fd_t s;
+
+        //  Handle corresponding to the listening socket.
+        handle_t handle;
+
+        //  If true file descriptor is registered with the poller and 'handle'
+        //  contains valid value.
+        bool handle_valid;
+
+        //  If true, connecter is waiting a while before trying to connect.
+        const bool delayed_start;
+
+        //  True iff a timer has been started.
+        bool timer_started;
+
+        //  Reference to the session we belong to.
+        zmq::session_base_t *session;
+
+        //  Current reconnect ivl, updated for backoff strategy
+        int current_reconnect_ivl;
+
+        // String representation of endpoint to connect to
+        std::string endpoint;
+
+        // Socket
+        zmq::socket_base_t *socket;
+
+        socks_connecter_t (const socks_connecter_t&);
+        const socks_connecter_t &operator = (const socks_connecter_t&);
+    };
+
+}
+
+#endif

src/stream_engine.cpp

@@ -54,6 +54,7 @@
 #include "config.hpp"
 #include "err.hpp"
 #include "ip.hpp"
+#include "tcp.hpp"
 #include "likely.hpp"
 #include "wire.hpp"
 
@@ -272,7 +273,7 @@ void zmq::stream_engine_t::in_event ()
         size_t bufsize = 0;
         decoder->get_buffer (&inpos, &bufsize);
 
-        int const rc = read (inpos, bufsize);
+        const int rc = tcp_read (s, inpos, bufsize);
         if (rc == 0) {
             error (connection_error);
             return;
@@ -359,7 +360,7 @@ void zmq::stream_engine_t::out_event ()
     //  arbitrarily large. However, we assume that underlying TCP layer has
     //  limited transmission buffer and thus the actual number of bytes
     //  written should be reasonably modest.
-    int nbytes = write (outpos, outsize);
+    const int nbytes = tcp_write (s, outpos, outsize);
 
     //  IO error has occurred. We stop waiting for output events.
     //  The engine is not terminated until we detect input error;
@@ -448,8 +449,8 @@ bool zmq::stream_engine_t::handshake ()
     zmq_assert (greeting_bytes_read < greeting_size);
     //  Receive the greeting.
     while (greeting_bytes_read < greeting_size) {
-        const int n = read (greeting_recv + greeting_bytes_read,
-                            greeting_size - greeting_bytes_read);
+        const int n = tcp_read (s, greeting_recv + greeting_bytes_read,
+                                greeting_size - greeting_bytes_read);
         if (n == 0) {
             error (connection_error);
             return false;
@@ -892,107 +893,6 @@ void zmq::stream_engine_t::error (error_reason_t reason)
     delete this;
 }
 
-int zmq::stream_engine_t::write (const void *data_, size_t size_)
-{
-#ifdef ZMQ_HAVE_WINDOWS
-
-    int nbytes = send (s, (char*) data_, (int) size_, 0);
-
-    //  If not a single byte can be written to the socket in non-blocking mode
-    //  we'll get an error (this may happen during the speculative write).
-    if (nbytes == SOCKET_ERROR && WSAGetLastError () == WSAEWOULDBLOCK)
-        return 0;
-
-    //  Signalise peer failure.
-    if (nbytes == SOCKET_ERROR && (
-          WSAGetLastError () == WSAENETDOWN ||
-          WSAGetLastError () == WSAENETRESET ||
-          WSAGetLastError () == WSAEHOSTUNREACH ||
-          WSAGetLastError () == WSAECONNABORTED ||
-          WSAGetLastError () == WSAETIMEDOUT ||
-          WSAGetLastError () == WSAECONNRESET))
-        return -1;
-
-    wsa_assert (nbytes != SOCKET_ERROR);
-    return nbytes;
-
-#else
-    ssize_t nbytes = send (s, data_, size_, 0);
-
-    //  Several errors are OK. When speculative write is being done we may not
-    //  be able to write a single byte from the socket. Also, SIGSTOP issued
-    //  by a debugging tool can result in EINTR error.
-    if (nbytes == -1 && (errno == EAGAIN || errno == EWOULDBLOCK ||
-          errno == EINTR))
-        return 0;
-
-    //  Signalise peer failure.
-    if (nbytes == -1) {
-        errno_assert (errno != EACCES
-                   && errno != EBADF
-                   && errno != EDESTADDRREQ
-                   && errno != EFAULT
-                   && errno != EINVAL
-                   && errno != EISCONN
-                   && errno != EMSGSIZE
-                   && errno != ENOMEM
-                   && errno != ENOTSOCK
-                   && errno != EOPNOTSUPP);
-        return -1;
-    }
-
-    return static_cast <int> (nbytes);
-
-#endif
-}
-
-int zmq::stream_engine_t::read (void *data_, size_t size_)
-{
-#ifdef ZMQ_HAVE_WINDOWS
-
-    const int rc = recv (s, (char*) data_, (int) size_, 0);
-
-    //  If not a single byte can be read from the socket in non-blocking mode
-    //  we'll get an error (this may happen during the speculative read).
-    if (rc == SOCKET_ERROR) {
-        if (WSAGetLastError () == WSAEWOULDBLOCK)
-            errno = EAGAIN;
-        else {
-            wsa_assert (WSAGetLastError () == WSAENETDOWN
-                     || WSAGetLastError () == WSAENETRESET
-                     || WSAGetLastError () == WSAECONNABORTED
-                     || WSAGetLastError () == WSAETIMEDOUT
-                     || WSAGetLastError () == WSAECONNRESET
-                     || WSAGetLastError () == WSAECONNREFUSED
-                     || WSAGetLastError () == WSAENOTCONN);
-            errno = wsa_error_to_errno (WSAGetLastError ());
-        }
-    }
-
-    return rc == SOCKET_ERROR? -1: rc;
-
-#else
-
-    const ssize_t rc = recv (s, data_, size_, 0);
-
-    //  Several errors are OK. When speculative read is being done we may not
-    //  be able to read a single byte from the socket. Also, SIGSTOP issued
-    //  by a debugging tool can result in EINTR error.
-    if (rc == -1) {
-        errno_assert (errno != EBADF
-                   && errno != EFAULT
-                   && errno != EINVAL
-                   && errno != ENOMEM
-                   && errno != ENOTSOCK);
-        if (errno == EWOULDBLOCK || errno == EINTR)
-            errno = EAGAIN;
-    }
-
-    return static_cast <int> (rc);
-
-#endif
-}
-
 void zmq::stream_engine_t::set_handshake_timer ()
 {
     zmq_assert (!has_handshake_timer);

src/stream_engine.hpp

@@ -92,16 +92,6 @@ namespace zmq
         //  Detects the protocol used by the peer.
         bool handshake ();
 
-        //  Writes data to the socket. Returns the number of bytes actually
-        //  written (even zero is to be considered to be a success). In case
-        //  of error or orderly shutdown by the other peer -1 is returned.
-        int write (const void *data_, size_t size_);
-
-        //  Reads data from the socket (up to 'size' bytes).
-        //  Returns the number of bytes actually read or -1 on error.
-        //  Zero indicates the peer has closed the connection.
-        int read (void *data_, size_t size_);
-
         int identity_msg (msg_t *msg_);
         int process_identity_msg (msg_t *msg_);
 

src/tcp.cpp

@@ -141,3 +141,104 @@ void zmq::tune_tcp_keepalives (fd_t s_, int keepalive_, int keepalive_cnt_, int
 #endif // ZMQ_HAVE_SO_KEEPALIVE
 #endif // ZMQ_HAVE_WINDOWS
 }
+
+int zmq::tcp_write (fd_t s_, const void *data_, size_t size_)
+{
+#ifdef ZMQ_HAVE_WINDOWS
+
+    int nbytes = send (s_, (char*) data_, (int) size_, 0);
+
+    //  If not a single byte can be written to the socket in non-blocking mode
+    //  we'll get an error (this may happen during the speculative write).
+    if (nbytes == SOCKET_ERROR && WSAGetLastError () == WSAEWOULDBLOCK)
+        return 0;
+
+    //  Signalise peer failure.
+    if (nbytes == SOCKET_ERROR && (
+          WSAGetLastError () == WSAENETDOWN ||
+          WSAGetLastError () == WSAENETRESET ||
+          WSAGetLastError () == WSAEHOSTUNREACH ||
+          WSAGetLastError () == WSAECONNABORTED ||
+          WSAGetLastError () == WSAETIMEDOUT ||
+          WSAGetLastError () == WSAECONNRESET))
+        return -1;
+
+    wsa_assert (nbytes != SOCKET_ERROR);
+    return nbytes;
+
+#else
+    ssize_t nbytes = send (s_, data_, size_, 0);
+
+    //  Several errors are OK. When speculative write is being done we may not
+    //  be able to write a single byte from the socket. Also, SIGSTOP issued
+    //  by a debugging tool can result in EINTR error.
+    if (nbytes == -1 && (errno == EAGAIN || errno == EWOULDBLOCK ||
+          errno == EINTR))
+        return 0;
+
+    //  Signalise peer failure.
+    if (nbytes == -1) {
+        errno_assert (errno != EACCES
+                   && errno != EBADF
+                   && errno != EDESTADDRREQ
+                   && errno != EFAULT
+                   && errno != EINVAL
+                   && errno != EISCONN
+                   && errno != EMSGSIZE
+                   && errno != ENOMEM
+                   && errno != ENOTSOCK
+                   && errno != EOPNOTSUPP);
+        return -1;
+    }
+
+    return static_cast <int> (nbytes);
+
+#endif
+}
+
+int zmq::tcp_read (fd_t s_, void *data_, size_t size_)
+{
+#ifdef ZMQ_HAVE_WINDOWS
+
+    const int rc = recv (s_, (char*) data_, (int) size_, 0);
+
+    //  If not a single byte can be read from the socket in non-blocking mode
+    //  we'll get an error (this may happen during the speculative read).
+    if (rc == SOCKET_ERROR) {
+        if (WSAGetLastError () == WSAEWOULDBLOCK)
+            errno = EAGAIN;
+        else {
+            wsa_assert (WSAGetLastError () == WSAENETDOWN
+                     || WSAGetLastError () == WSAENETRESET
+                     || WSAGetLastError () == WSAECONNABORTED
+                     || WSAGetLastError () == WSAETIMEDOUT
+                     || WSAGetLastError () == WSAECONNRESET
+                     || WSAGetLastError () == WSAECONNREFUSED
+                     || WSAGetLastError () == WSAENOTCONN);
+            errno = wsa_error_to_errno (WSAGetLastError ());
+        }
+    }
+
+    return rc == SOCKET_ERROR? -1: rc;
+
+#else
+
+    const ssize_t rc = recv (s_, data_, size_, 0);
+
+    //  Several errors are OK. When speculative read is being done we may not
+    //  be able to read a single byte from the socket. Also, SIGSTOP issued
+    //  by a debugging tool can result in EINTR error.
+    if (rc == -1) {
+        errno_assert (errno != EBADF
+                   && errno != EFAULT
+                   && errno != EINVAL
+                   && errno != ENOMEM
+                   && errno != ENOTSOCK);
+        if (errno == EWOULDBLOCK || errno == EINTR)
+            errno = EAGAIN;
+    }
+
+    return static_cast <int> (rc);
+
+#endif
+}

src/tcp.hpp

@@ -37,6 +37,16 @@ namespace zmq
     //  Tunes TCP keep-alives
     void tune_tcp_keepalives (fd_t s_, int keepalive_, int keepalive_cnt_, int keepalive_idle_, int keepalive_intvl_);
 
+    //  Writes data to the socket. Returns the number of bytes actually
+    //  written (even zero is to be considered to be a success). In case
+    //  of error or orderly shutdown by the other peer -1 is returned.
+    int tcp_write (fd_t s_, const void *data_, size_t size_);
+
+    //  Reads data from the socket (up to 'size' bytes).
+    //  Returns the number of bytes actually read or -1 on error.
+    //  Zero indicates the peer has closed the connection.
+    int tcp_read (fd_t s_, void *data_, size_t size_);
+
 }
 
 #endif