Conf option to have an end to end ipv6 otp release

 - add support for ipv6 connections to Epmd
 - add a macro to define the default epmd ip: "::1" or "127.0.0.1"
 - add a macro to define the default proto_dist: inet_tcp or inet6_tcp
 - add a configure option to compile the whole otp in ipv6 default mode

The option --enable-epmd-ipv6 configures:

- the -DEPMD6 CFLAG for epmd compilation
- the default proto_dist (without init arg) to "inet6_tcp"
- the epmd connection ip to "::1"

configure.in

@@ -236,6 +236,10 @@ AC_ARG_ENABLE(native-libs,
 AS_HELP_STRING([--enable-native-libs],
                [compile Erlang libraries to native code]))
 
+AC_ARG_ENABLE(epmd-ipv6,
+AS_HELP_STRING([--enable-epmd-ipv6],
+               [enable epmd ipv6 communication instead of ipv4]))
+
 AC_ARG_WITH(dynamic-trace,
 AS_HELP_STRING([--with-dynamic-trace={dtrace|systemtap}],
 	       [specify use of dynamic trace framework, dtrace or systemtap])
@@ -419,6 +423,13 @@ if test X${enable_native_libs} = Xyes -a X${enable_hipe} != Xno; then
 fi
 AC_SUBST(NATIVE_LIBS_ENABLED)
 
+EPMD_IPV6_ENABLED=
+if test X${enable_epmd_ipv6} = Xyes; then
+    CFLAGS="-DEPMD6 $CFLAGS"
+    export CFLAGS
+    EPMD_IPV6_ENABLED=yes
+fi
+AC_SUBST(EPMD_IPV6_ENABLED)
 
 rm -f $ERL_TOP/lib/SKIP-APPLICATIONS
 for app in `cd lib && ls -d *`; do

erts/configure.in

@@ -214,6 +214,10 @@ AC_ARG_ENABLE(native-libs,
 AS_HELP_STRING([--enable-native-libs],
                [compile Erlang libraries to native code]))
 
+AC_ARG_ENABLE(epmd-ipv6,
+AS_HELP_STRING([--enable-epmd-ipv6],
+               [enable epmd ipv6 communication instead of ipv4]))
+
 AC_ARG_ENABLE(fp-exceptions,
 AS_HELP_STRING([--enable-fp-exceptions],
                [use hardware floating point exceptions (default if hipe enabled)]),
@@ -3502,6 +3506,14 @@ if test X${enable_native_libs} = Xyes -a X${HIPE_ENABLED} = Xyes; then
 fi
 AC_SUBST(NATIVE_LIBS_ENABLED)
 
+EPMD_IPV6_ENABLED=
+if test X${enable_epmd_ipv6} = Xyes; then
+    CFLAGS="-DEPMD6 $CFLAGS"
+    export CFLAGS
+    EPMD_IPV6_ENABLED=yes
+fi
+AC_SUBST(EPMD_IPV6_ENABLED)
+
 #
 # Check if HiPE should use a standard installation of perfctr.
 #

erts/epmd/src/epmd_srv.c

@@ -1006,8 +1006,8 @@ static int conn_open(EpmdVars *g,int fd)
 
   for (i = 0; i < g->max_conn; i++) {
     if (g->conn[i].open == EPMD_FALSE) {
-      struct sockaddr_in si;
-      struct sockaddr_in di;
+      struct sockaddr_storage si;
+      struct sockaddr_storage di;
 #ifdef HAVE_SOCKLEN_T
       socklen_t st;
 #else
@@ -1026,18 +1026,31 @@ static int conn_open(EpmdVars *g,int fd)
       s->keep = EPMD_FALSE;
 
       /* Determine if connection is from localhost */
-      if (getpeername(s->fd,(struct sockaddr*) &si,&st) ||
-	  st < sizeof(si)) {
+      if (getpeername(s->fd,(struct sockaddr*) &si,&st)) {
 	  /* Failure to get peername is regarded as non local host */
 	  s->local_peer = EPMD_FALSE;
       } else {
-	  /* Only 127.x.x.x and connections from the host's IP address
-	     allowed, no false positives */
-	  s->local_peer =
-	      (((((unsigned) ntohl(si.sin_addr.s_addr)) & 0xFF000000U) ==
-	       0x7F000000U) ||
-	       (getsockname(s->fd,(struct sockaddr*) &di,&st) ?
-	       EPMD_FALSE : si.sin_addr.s_addr == di.sin_addr.s_addr));
+          if (si.ss_family == AF_INET) {
+              struct sockaddr_in *si4 = (struct sockaddr_in *)&si;
+              struct sockaddr_in *di4 = (struct sockaddr_in *)&di;
+	          /* Only 127.x.x.x and connections from the host's IP address
+	             allowed, no false positives */
+	          s->local_peer =
+	              (((((unsigned) ntohl(si4->sin_addr.s_addr)) & 0xFF000000U) ==
+	               0x7F000000U) ||
+	               (getsockname(s->fd,(struct sockaddr*) di4,&st) ?
+	               EPMD_FALSE : si4->sin_addr.s_addr == di4->sin_addr.s_addr));
+          } else { // AF_INET6
+              struct sockaddr_in6 *si6 = (struct sockaddr_in6 *)&si;
+              struct sockaddr_in6 *di6 = (struct sockaddr_in6 *)&di;
+              /* The same rule than for AF_INET, but only ::1 is local in ipv6 */
+              static const unsigned char inet6_localhost[] =
+                    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 };
+	          s->local_peer = 
+	              ((memcmp(si6->sin6_addr.s6_addr, inet6_localhost, 16) == 0) ||
+	               (getsockname(s->fd,(struct sockaddr*) di6,&st) ? EPMD_FALSE :
+                    (memcmp(si6->sin6_addr.s6_addr,di6->sin6_addr.s6_addr,16) == 0)));
+          }
       }
       dbg_tty_printf(g,2,(s->local_peer) ? "Local peer connected" :
 		     "Non-local peer connected");

lib/kernel/src/erl_epmd.erl

@@ -28,6 +28,12 @@
 -define(port_please_failure2(Term), noop).
 -endif.
 
+-ifdef(EPMD_IPV6).
+-define(DEFAULT_EPMD_IP, {0,0,0,0,0,0,0,1}).
+-else.
+-define(DEFAULT_EPMD_IP, {127,0,0,1}).
+-endif.
+
 %% External exports
 -export([start/0, start_link/0, stop/0, port_please/2, 
 	 port_please/3, names/0, names/1,
@@ -190,7 +196,7 @@ get_epmd_port() ->
 %%
 %% Epmd socket
 %%
-open() -> open({127,0,0,1}).  % The localhost IP address.
+open() -> open(?DEFAULT_EPMD_IP).  % The localhost IP address.
 
 open({A,B,C,D}=EpmdAddr) when ?ip(A,B,C,D) ->
     gen_tcp:connect(EpmdAddr, get_epmd_port(), [inet]);

lib/kernel/src/net_kernel.erl

@@ -52,6 +52,12 @@
 -define(tckr_dbg(X), ok).
 -endif.
 
+-ifdef(EPMD_IPV6).
+-define(DEFAULT_PROTO_DIST, "inet6_tcp").
+-else.
+-define(DEFAULT_PROTO_DIST, "inet_tcp").
+-endif.
+
 %% User Interface Exports
 -export([start/1, start_link/1, stop/0,
 	 kernel_apply/3,
@@ -1275,7 +1281,7 @@ protocol_childspecs() ->
 	{ok, [Protos]} ->
 	    protocol_childspecs(Protos);
 	_ ->
-	    protocol_childspecs(["inet_tcp"])
+	    protocol_childspecs([?DEFAULT_PROTO_DIST])
     end.
 
 protocol_childspecs([]) ->
@@ -1311,7 +1317,7 @@ start_protos(Name,Node) ->
 	{ok, [Protos]} ->
 	    start_protos(Name,Protos, Node);
 	_ ->
-	    start_protos(Name,["inet_tcp"], Node)
+	    start_protos(Name,[?DEFAULT_PROTO_DIST], Node) 
     end.
 
 start_protos(Name,Ps, Node) ->

make/otp.mk.in

@@ -60,6 +60,12 @@ DUBIOUS_ORIGINS = /undefined/environment/
 HIPE_ENABLED=@HIPE_ENABLED@
 NATIVE_LIBS_ENABLED=@NATIVE_LIBS_ENABLED@
 
+# ----------------------------------------------------
+#	Epmd default IPV6
+# ----------------------------------------------------
+
+EPMD_IPV6_ENABLED=@EPMD_IPV6_ENABLED@
+
 # ----------------------------------------------------
 #	Command macros
 # ----------------------------------------------------
@@ -98,6 +104,11 @@ else
     ERL_COMPILE_FLAGS += +debug_info
   endif
 endif
+
+ifeq ($(EPMD_IPV6_ENABLED),yes)
+ERL_COMPILE_FLAGS += -DEPMD_IPV6
+endif
+
 ERLC_WFLAGS = -W
 ERLC = erlc $(ERLC_WFLAGS) $(ERLC_FLAGS)
 ERL = erl -boot start_clean