ZMQ_IPV4ONLY option added

At this point option exists, is documented and can be set,
however, it has no effect.

Signed-off-by: Steven McCoy <steven.mccoy@miru.hk>
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

doc/zmq_getsockopt.txt

@@ -329,6 +329,21 @@ Default value:: -1 (infinite)
 Applicable socket types:: all
 
 
+ZMQ_IPV4ONLY: Retrieve IPv4-only socket override status
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Retrieve the underlying native socket type.  A value of `1` will use IPv4
+sockets, while the default value of `0` will use IPv6 sockets. An IPv6 socket
+lets applications connect to and accept connections from both IPv4 and IPv6
+hosts.
+
+[horizontal]
+Option value type:: int
+Option value unit:: boolean
+Default value:: 1 (true)
+Applicable socket types:: all, when using TCP transports.
+
+
 ZMQ_FD: Retrieve file descriptor associated with the socket
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The 'ZMQ_FD' option shall retrieve the file descriptor associated with the

doc/zmq_setsockopt.txt

@@ -321,6 +321,20 @@ Default value:: -1 (infinite)
 Applicable socket types:: all
 
 
+ZMQ_IPV4ONLY: Use IPv4-only sockets
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Sets the underlying native socket type.  A value of `1` will use IPv4 sockets,
+while the default value of `0` will use IPv6 sockets. An IPv6 socket lets 
+applications connect to and accept connections from both IPv4 and IPv6 hosts.
+
+[horizontal]
+Option value type:: int
+Option value unit:: boolean
+Default value:: 1 (true)
+Applicable socket types:: all, when using TCP transports.
+
+
 RETURN VALUE
 ------------
 The _zmq_setsockopt()_ function shall return zero if successful. Otherwise it

doc/zmq_tcp.txt

@@ -31,13 +31,13 @@ colon and the TCP port number to use.
 An 'interface' may be specified by either of the following:
 
 * The wild-card `*`, meaning all available interfaces.
-* The primary IPv4 address assigned to the interface, in its numeric
+* The primary IPv4 or IPv6 address assigned to the interface, in its numeric
   representation.
 * The interface name as defined by the operating system.
 
 NOTE: Interface names are not standardised in any way and should be assumed to
 be arbitrary and platform dependent. On Win32 platforms no short interface
-names exist, thus only the primary IPv4 address may be used to specify an
+names exist, thus only the primary IP address may be used to specify an
 'interface'.
 
 Connecting a socket
@@ -49,7 +49,7 @@ a colon and the TCP port number to use.
 A 'peer address' may be specified by either of the following:
 
 * The DNS name of the peer.
-* The IPv4 address of the peer, in it's numeric representation.
+* The IPv4 or IPv6 address of the peer, in it's numeric representation.
 
 
 WIRE FORMAT

include/zmq.h

@@ -185,7 +185,8 @@ ZMQ_EXPORT int zmq_term (void *context);
 #define ZMQ_SNDTIMEO 28
 #define ZMQ_RCVLABEL 29
 #define ZMQ_RCVCMD 30
-    
+#define ZMQ_IPV4ONLY 31
+
 /*  Send/recv options.                                                        */
 #define ZMQ_DONTWAIT 1
 #define ZMQ_SNDMORE 2

src/options.cpp

@@ -40,6 +40,7 @@ zmq::options_t::options_t () :
     maxmsgsize (-1),
     rcvtimeo (-1),
     sndtimeo (-1),
+    ipv4only (1),
     delay_on_close (true),
     delay_on_disconnect (true),
     filter (false)
@@ -179,6 +180,21 @@ int zmq::options_t::setsockopt (int option_, const void *optval_,
         sndtimeo = *((int*) optval_);
         return 0;
 
+    case ZMQ_IPV4ONLY:
+        {
+            if (optvallen_ != sizeof (int)) {
+                errno = EINVAL;
+                return -1;
+            }
+            int val = *((int*) optval_);
+            if (val != 0 && val != 1) {
+                errno = EINVAL;
+                return -1;
+            }
+            ipv4only = val;
+            return 0;
+        }
+
     }
 
     errno = EINVAL;
@@ -333,6 +349,15 @@ int zmq::options_t::getsockopt (int option_, void *optval_, size_t *optvallen_)
         *optvallen_ = sizeof (int);
         return 0;
 
+    case ZMQ_IPV4ONLY:
+        if (*optvallen_ < sizeof (int)) {
+            errno = EINVAL;
+            return -1;
+        }
+        *((int*) optval_) = ipv4only;
+        *optvallen_ = sizeof (int);
+        return 0;
+
     }
 
     errno = EINVAL;

src/options.hpp

@@ -78,6 +78,11 @@ namespace zmq
         int rcvtimeo;
         int sndtimeo;
 
+        //  If 1, indicates the use of IPv4 sockets only, it will not be
+        //  possible to communicate with IPv6-only hosts. If 0, the socket can
+        //  connect to and accept connections from both IPv4 and IPv6 hosts.
+        int ipv4only;
+
         //  If true, session reads all the pending messages from the pipe and
         //  sends them to the network when socket is closed.
         bool delay_on_close;