epmd: support IPv6 node registration

Allow IPv6 nodes to register with and query epmd. On systems with
IPv6 support:

* epmd listens on both the IPv4 and IPv6 ANY or loopback sockets

* the epmd cli client connects to epmd over the IPv6 loopback

* distributed nodes started with "-proto_dist inet6_tcp" will register
  with epmd over IPv6

To work on IPv6 capable systems that have IPv6 support disabled,
epmd ignores errors opening the socket if the protocol is not
supported. Similarly, the epmd client will fall back to IPv4 if the IPv6
socket is not available.

Update the minimum supported version of Windows to Windows Vista to
support IPv6.

1 files changed, 30 insertions, 3 deletions

diff --git a/erts/epmd/test/epmd_SUITE.erl b/erts/epmd/test/epmd_SUITE.erl
index 4de65500e9..d5837e5b8c 100644
--- a/erts/epmd/test/epmd_SUITE.erl
+++ b/erts/epmd/test/epmd_SUITE.erl
@@ -43,6 +43,7 @@
 -export(
    [
     register_name/1,
+    register_name_ipv6/1,
     register_names_1/1,
     register_names_2/1,
     register_duplicate_name/1,
@@ -113,7 +114,8 @@
 suite() -> [{ct_hooks,[ts_install_cth]}].
 
 all() -> 
-    [register_name, register_names_1, register_names_2,
+    [register_name, register_name_ipv6,
+     register_names_1, register_names_2,
      register_duplicate_name, unicode_name, long_unicode_name,
      get_port_nr, slow_get_port_nr,
      unregister_others_name_1, unregister_others_name_2,
@@ -172,6 +174,24 @@ register_name(Config) when is_list(Config) ->
     ?line ok = close(Sock),			% Unregister
     ok.
 
+register_name_ipv6(doc) ->
+    ["Register a name over IPv6"];
+register_name_ipv6(suite) ->
+    [];
+register_name_ipv6(Config) when is_list(Config) ->
+    % Test if the host has an IPv6 loopback address
+    Res = gen_tcp:listen(0, [inet6, {ip, {0,0,0,0,0,0,0,1}}]),
+    case Res of
+    {ok,LSock} ->
+	    gen_tcp:close(LSock),
+	    ?line ok = epmdrun(),
+	    ?line {ok,Sock} = register_node6("foobar6"),
+	    ?line ok = close(Sock),         % Unregister
+	    ok;
+    _Error ->
+	    {skip, "Host does not have an IPv6 loopback address"}
+    end.
+
 register_names_1(doc) ->
     ["Register and unregister two nodes"];
 register_names_1(suite) ->
@@ -245,9 +265,14 @@ register_node(Name) ->
 register_node(Name,Port) ->
     register_node_v2(Port,$M,0,5,5,Name,"").
 
+register_node6(Name) ->
+    register_node_v2({0,0,0,0,0,0,0,1},?DUMMY_PORT,$M,0,5,5,Name,"").
+
 register_node_v2(Port, NodeType, Prot, HVsn, LVsn, Name, Extra) ->
+    register_node_v2("localhost", Port, NodeType, Prot, HVsn, LVsn, Name, Extra).
+register_node_v2(Addr, Port, NodeType, Prot, HVsn, LVsn, Name, Extra) ->
     Req = alive2_req(Port, NodeType, Prot, HVsn, LVsn, Name, Extra),
-    case send_req(Req) of
+    case send_req(Req, Addr) of
 	{ok,Sock} ->
 	    case recv(Sock,4) of
 		{ok, [?EPMD_ALIVE2_RESP,_Res=0,_C0,_C1]} ->
@@ -1186,7 +1211,9 @@ send_direct(Sock, Bytes) ->
     end.
 
 send_req(Req) ->
-    case connect() of
+    send_req(Req, "localhost").
+send_req(Req, Addr) ->
+    case connect(Addr) of
 	{ok,Sock} ->
 	    case send(Sock, [size16(Req), Req]) of
 		ok ->