Update resolve_ip_interface and resolve_ip_hostname with ipv4only parameter.

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

src/ip.cpp

@@ -213,7 +213,7 @@ static int resolve_nic_name (struct sockaddr* addr_, char const *interface_,
 #endif
 
 int zmq::resolve_ip_interface (sockaddr_storage* addr_, socklen_t *addr_len_,
-    char const *interface_)
+    char const *interface_, bool ipv4only_)
 {
     //  Find the ':' at end that separates NIC name from service.
     const char *delimiter = strrchr (interface_, ':');
@@ -241,18 +241,27 @@ int zmq::resolve_ip_interface (sockaddr_storage* addr_, socklen_t *addr_len_,
     sockaddr *out_addr = (sockaddr *) &ss;
     socklen_t out_addrlen;
 
-    //  Initialise IPv4-format family/port.
+    //  Initialise IP-format family/port and populate temporary output pointers
+    //  with the address.
+    if (ipv4only_) {
         sockaddr_in ip4_addr;
         memset (&ip4_addr, 0, sizeof (ip4_addr));
         ip4_addr.sin_family = AF_INET;
         ip4_addr.sin_port = sin_port;
         ip4_addr.sin_addr.s_addr = htonl (INADDR_ANY);
-
-    //  Populate temporary output pointers with ip4_addr.
         out_addrlen = (socklen_t) sizeof (ip4_addr);
         memcpy (out_addr, &ip4_addr, out_addrlen);
+    } else {
+        sockaddr_in6 ip6_addr;
+        memset (&ip6_addr, 0, sizeof (ip6_addr));
+        ip6_addr.sin6_family = AF_INET6;
+        ip6_addr.sin6_port = sin_port;
+        memcpy (&ip6_addr.sin6_addr, &in6addr_any, sizeof (in6addr_any));
+        out_addrlen = (socklen_t) sizeof (ip6_addr);
+        memcpy (out_addr, &ip6_addr, out_addrlen);
+    }
 
-    //  * resolves to INADDR_ANY.
+    //  * resolves to INADDR_ANY or in6addr_any.
     if (iface.compare("*") == 0) {
         zmq_assert (out_addrlen <= (socklen_t) sizeof (*addr_));
         memcpy (addr_, out_addr, out_addrlen);
@@ -261,7 +270,7 @@ int zmq::resolve_ip_interface (sockaddr_storage* addr_, socklen_t *addr_len_,
     }
 
     //  Try to resolve the string as a NIC name.
-    int rc = resolve_nic_name (out_addr, iface.c_str(), true);
+    int rc = resolve_nic_name (out_addr, iface.c_str(), ipv4only_);
     if (rc != 0 && errno != ENODEV)
         return rc;
     if (rc == 0) {
@@ -281,8 +290,9 @@ int zmq::resolve_ip_interface (sockaddr_storage* addr_, socklen_t *addr_len_,
 #endif
     memset (&req, 0, sizeof (req));
 
-    //  We only support IPv4 addresses for now.
-    req.ai_family = AF_INET;
+    //  Choose IPv4 or IPv6 protocol family. Note that IPv6 allows for
+    //  IPv4-in-IPv6 addresses.
+    req.ai_family = ipv4only_ ? AF_INET : AF_INET6;
 
     //  Arbitrary, not used in the output, but avoids duplicate results.
     req.ai_socktype = SOCK_STREAM;
@@ -291,6 +301,15 @@ int zmq::resolve_ip_interface (sockaddr_storage* addr_, socklen_t *addr_len_,
     //  service-name irregularity due to indeterminate socktype.
     req.ai_flags = AI_PASSIVE | AI_NUMERICHOST | AI_NUMERICSERV;
 
+#ifndef ZMQ_HAVE_WINDOWS
+    //  Windows by default maps IPv4 addresses into IPv6. In this API we only
+    //  require IPv4-mapped addresses when no native IPv6 interfaces are
+    //  available (~AI_ALL).  This saves an additional DNS roundtrip for IPv4
+    //  addresses.
+    if (req.ai_family == AF_INET6)
+        req.ai_flags |= AI_V4MAPPED;
+#endif
+
     //  Resolve the literal address. Some of the error info is lost in case
     //  of error, however, there's no way to report EAI errors via errno.
     rc = getaddrinfo (iface.c_str(), service.c_str(), &req, &res);
@@ -312,7 +331,7 @@ int zmq::resolve_ip_interface (sockaddr_storage* addr_, socklen_t *addr_len_,
 }
 
 int zmq::resolve_ip_hostname (sockaddr_storage *addr_, socklen_t *addr_len_,
-    const char *hostname_)
+    const char *hostname_, bool ipv4only_)
 {
     //  Find the ':' that separates hostname name from service.
     const char *delimiter = strrchr (hostname_, ':');
@@ -329,8 +348,9 @@ int zmq::resolve_ip_hostname (sockaddr_storage *addr_, socklen_t *addr_len_,
     addrinfo req;
     memset (&req, 0, sizeof (req));
 
-    //  We only support IPv4 addresses for now.
-    req.ai_family = AF_INET;
+    //  Choose IPv4 or IPv6 protocol family. Note that IPv6 allows for
+    //  IPv4-in-IPv6 addresses.
+    req.ai_family = ipv4only_ ? AF_INET : AF_INET6;
 
     //  Need to choose one to avoid duplicate results from getaddrinfo() - this
     //  doesn't really matter, since it's not included in the addr-output.
@@ -339,6 +359,14 @@ int zmq::resolve_ip_hostname (sockaddr_storage *addr_, socklen_t *addr_len_,
     //  Avoid named services due to unclear socktype.
     req.ai_flags = AI_NUMERICSERV;
 
+#ifndef ZMQ_HAVE_WINDOWS
+    //  Windows by default maps IPv4 addresses into IPv6. In this API we only
+    //  require IPv4-mapped addresses when no native IPv6 interfaces are
+    //  available.  This saves an additional DNS roundtrip for IPv4 addresses.
+    if (req.ai_family == AF_INET6)
+        req.ai_flags |= AI_V4MAPPED;
+#endif
+
     //  Resolve host name. Some of the error info is lost in case of error,
     //  however, there's no way to report EAI errors via errno.
     addrinfo *res;

src/ip.hpp

@@ -51,12 +51,12 @@ namespace zmq
     //  Resolves network interface name in <nic-name>:<port> format. Symbol "*"
     //  (asterisk) resolves to INADDR_ANY (all network interfaces).
     int resolve_ip_interface (sockaddr_storage *addr_, socklen_t *addr_len_,
-        char const *interface_);
+        char const *interface_, bool ipv4only_);
 
     //  This function resolves a string in <hostname>:<port-number> format.
     //  Hostname can be either the name of the host or its IP address.
     int resolve_ip_hostname (sockaddr_storage *addr_, socklen_t *addr_len_,
-        const char *hostname_);
+        const char *hostname_, bool ipv4only_);
 
     //  This function sets up address for UNIX domain transport.
     int resolve_local_path (sockaddr_storage *addr_, socklen_t *addr_len_,

src/tcp_connecter.cpp

@@ -179,7 +179,7 @@ int zmq::tcp_connecter_t::get_new_reconnect_ivl ()
 
 int zmq::tcp_connecter_t::set_address (const char *addr_)
 {
-    return resolve_ip_hostname (&addr, &addr_len, addr_);
+    return resolve_ip_hostname (&addr, &addr_len, addr_, options.ipv4only);
 }
 
 int zmq::tcp_connecter_t::open ()

src/tcp_listener.cpp

@@ -123,7 +123,7 @@ void zmq::tcp_listener_t::close ()
 int zmq::tcp_listener_t::set_address (const char *addr_)
 {
     //  Convert the interface into sockaddr_in structure.
-    int rc = resolve_ip_interface (&addr, &addr_len, addr_);
+    int rc = resolve_ip_interface (&addr, &addr_len, addr_, options.ipv4only);
     if (rc != 0)
         return -1;
 

src/vtcp_connecter.cpp

@@ -92,7 +92,8 @@ int zmq::vtcp_connecter_t::set_address (const char *addr_)
         addr_str += ":9220";
         std::string subport_str (delimiter + 1);
         subport = (vtcp_subport_t) atoi (subport_str.c_str ());
-        int rc = resolve_ip_hostname (&addr, &addr_len, addr_str.c_str ());
+        int rc = resolve_ip_hostname (&addr, &addr_len, addr_str.c_str (),
+            true);
         if (rc != 0)
             return -1;
     }
@@ -100,7 +101,8 @@ int zmq::vtcp_connecter_t::set_address (const char *addr_)
         std::string addr_str (addr_, delimiter - addr_);
         std::string subport_str (delimiter + 1);
         subport = (vtcp_subport_t) atoi (subport_str.c_str ());
-        int rc = resolve_ip_hostname (&addr, &addr_len, addr_str.c_str ());
+        int rc = resolve_ip_hostname (&addr, &addr_len, addr_str.c_str (),
+            true);
         if (rc != 0)
             return -1;
     }