Index: ext/socket/raddrinfo.c
===================================================================
--- ext/socket/raddrinfo.c	(revision 36348)
+++ ext/socket/raddrinfo.c	(working copy)
@@ -1793,6 +1793,18 @@ addrinfo_ipv6_sitelocal_p(VALUE self)
 }
 
 /*
+ * Returns true for IPv6 unique local address (fc00::/7, RFC4193).
+ * It returns false otherwise.
+ */
+static VALUE
+addrinfo_ipv6_unique_local_p(VALUE self)
+{
+    struct in6_addr *addr = extract_in6_addr(self);
+    if (addr && IN6_IS_ADDR_UNIQUE_LOCAL(addr)) return Qtrue;
+    return Qfalse;
+}
+
+/*
  * Returns true for IPv4-mapped IPv6 address (::ffff:0:0/80).
  * It returns false otherwise.
  */
@@ -2207,6 +2219,7 @@ rsock_init_addrinfo(void)
     rb_define_method(rb_cAddrinfo, "ipv6_multicast?", addrinfo_ipv6_multicast_p, 0);
     rb_define_method(rb_cAddrinfo, "ipv6_linklocal?", addrinfo_ipv6_linklocal_p, 0);
     rb_define_method(rb_cAddrinfo, "ipv6_sitelocal?", addrinfo_ipv6_sitelocal_p, 0);
+    rb_define_method(rb_cAddrinfo, "ipv6_unique_local?", addrinfo_ipv6_unique_local_p, 0);
     rb_define_method(rb_cAddrinfo, "ipv6_v4mapped?", addrinfo_ipv6_v4mapped_p, 0);
     rb_define_method(rb_cAddrinfo, "ipv6_v4compat?", addrinfo_ipv6_v4compat_p, 0);
     rb_define_method(rb_cAddrinfo, "ipv6_mc_nodelocal?", addrinfo_ipv6_mc_nodelocal_p, 0);
Index: test/socket/test_addrinfo.rb
===================================================================
--- test/socket/test_addrinfo.rb	(revision 36348)
+++ test/socket/test_addrinfo.rb	(working copy)
@@ -512,7 +512,8 @@ class TestSocketAddrinfo < Test::Unit::T
         [:ipv6_v4mapped?, "::ffff:0.0.0.0", "::ffff:255.255.255.255"],
         [:ipv6_linklocal?, "fe80::", "febf::"],
         [:ipv6_sitelocal?, "fec0::", "feef::"],
-        [:ipv6_multicast?, "ff00::", "ffff::"]
+        [:ipv6_multicast?, "ff00::", "ffff::"],
+        [:ipv6_unique_local?, "fc00::", "fd00::"],
       ]
       mlist = [
         [:ipv6_mc_nodelocal?, "ff01::", "ff11::"],
Index: test/socket/test_socket.rb
===================================================================
--- test/socket/test_socket.rb	(revision 36348)
+++ test/socket/test_socket.rb	(working copy)
@@ -334,6 +334,8 @@ class TestSocket < Test::Unit::TestCase
           end
         when /darwin/
           if !ai.ipv6?
+          elsif ai.ipv6_unique_local?
+            next true # iCloud addresses do not work, see Bug 6692
           elsif ifr_name = ai.ip_address[/%(.*)/, 1]
             # Mac OS X may sets IFDISABLED as FreeBSD does
             ulSIOCGIFFLAGS = 3223349521