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 The interaction between IPv4 and IPv6 sockets depends on the platform: * FreeBSD allows multiple "specific" sockets to bind the same port (such as 2 sockets listening to the same port on ANY and the loopback). Binding port 4369 to IPv4 and IPv6 sockets simulataneously is allowed. * Linux does not allow the same port to be bound by different sockets. Setting the IPV6_V6ONLY socket option is required. * Windows The behaviour differs depending on the version of Windows: http://msdn.microsoft.com/en-us/library/windows/desktop/bb513665(v=vs.85).aspx According to the site, sockets on Windows XP with Service Pack 1 (SP1) and Windows Server 2003 will only listen on either IPv4 or IPv6, so creating two sockets is required to service IPv4 and IPv6 traffic on the same port. The IPV6_V6ONLY socket option is not supported. For Windows Vista and later, a single socket can handle IPv4 and IPv6 traffic for the same port. The IPV6_V6ONLY socket option is supported and is enabled for IPv6 sockets by default.
msantos · May 3, 2013 · d3d6846 · d3d6846
1 parent d08b977
commit d3d6846
Show file tree

Hide file tree

Showing 9 changed files with 248 additions and 93 deletions.
diff --git a/erts/doc/src/epmd.xml b/erts/doc/src/epmd.xml
@@ -36,7 +36,7 @@
   <comsummary>
   <p>Erlang Port Mapper Daemon</p>
   <taglist>
-  <tag><c><![CDATA[epmd [-d|-debug] [DbgExtra...] [-port No] [-daemon] [-relaxed_command_check]]]></c></tag>
+  <tag><c><![CDATA[epmd [-d|-debug] [DbgExtra...] [-address Addresses] [-port No] [-daemon] [-relaxed_command_check]]]></c></tag>
   <item>
   <p>Starts the port mapper daemon</p>
   </item>

diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml
@@ -381,6 +381,28 @@
           similar to <c><![CDATA[code:add_pathsz/1]]></c>. See
           <seealso marker="kernel:code">code(3)</seealso>.</p>
       </item>
+      <tag><c><![CDATA[-proto_dist Proto]]></c></tag>
+      <item>
+        <p>Specify a protocol for Erlang distribution.</p>
+	    <taglist>
+	      <tag><c>inet_tcp</c></tag>
+              <item>
+                  <p>TCP over IPv4 (the default)</p>
+              </item>
+	      <tag><c>inet_ssl</c></tag>
+              <item>
+                  <p>distribution over SSL</p>
+              </item>
+	      <tag><c>inet6_tcp</c></tag>
+              <item>
+                  <p>TCP over IPv6</p>
+              </item>
+        </taglist>
+        <p>For example, to start up IPv6 distributed nodes:</p>
+<pre>
+% <input>erl -name test@ipv6node.example.com -proto_dist inet6_tcp</input>
+</pre>
+      </item>
       <tag><c><![CDATA[-remsh Node]]></c></tag>
       <item>
         <p>Starts Erlang with a remote shell connected to <c><![CDATA[Node]]></c>.</p>

diff --git a/erts/epmd/src/epmd.c b/erts/epmd/src/epmd.c
@@ -335,10 +335,10 @@ static void run_daemon(EpmdVars *g)
     for (fd = 0; fd < g->max_conn ; fd++) /* close all files ... */
         close(fd);
     /* Syslog on linux will try to write to whatever if we dont
-       inform it of that the log is closed. */
+       inform it that the log is closed. */
     closelog();
 
-    /* These chouldn't be needed but for safety... */
+    /* These shouldn't be needed but for safety... */
 
     open("/dev/null", O_RDONLY); /* Order is important! */
     open("/dev/null", O_WRONLY);
@@ -379,7 +379,7 @@ static void run_daemon(EpmdVars *g)
     close(1);
     close(2);
 
-    /* These chouldn't be needed but for safety... */
+    /* These shouldn't be needed but for safety... */
 
     open("nul", O_RDONLY);
     open("nul", O_WRONLY);

diff --git a/erts/epmd/src/epmd_cli.c b/erts/epmd/src/epmd_cli.c
@@ -135,6 +135,7 @@ void epmd_call(EpmdVars *g,int what)
 static int conn_to_epmd(EpmdVars *g)
 {
     struct EPMD_SOCKADDR_IN address;
+    size_t salen = 0;
     int connect_sock;
 
     connect_sock = socket(FAMILY, SOCK_STREAM, 0);
@@ -143,10 +144,16 @@ static int conn_to_epmd(EpmdVars *g)
 
     { /* store port number in unsigned short */
       unsigned short sport = g->port;
-      SET_ADDR(address, EPMD_ADDR_LOOPBACK, sport);
+#if defined(HAVE_IN6) && defined(AF_INET6)
+      SET_ADDR6(address, in6addr_loopback, sport);
+      salen = sizeof(struct sockaddr_in6);
+#else
+      SET_ADDR(address, htonl(INADDR_LOOPBACK), sport);
+      salen = sizeof(struct sockaddr_in);
+#endif
     }
 
-    if (connect(connect_sock, (struct sockaddr*)&address, sizeof address) < 0) 
+    if (connect(connect_sock, (struct sockaddr*)&address, salen) < 0)
 	goto error;
     return connect_sock;
 

diff --git a/erts/epmd/src/epmd_int.h b/erts/epmd/src/epmd_int.h
@@ -46,9 +46,14 @@
 #include <string.h>
 
 #ifdef __WIN32__
+#  ifdef _WIN32_WINVER
+#    undef _WIN32_WINVER
+#  endif
+#  define _WIN32_WINVER 0x0501
 #  ifndef WINDOWS_H_INCLUDES_WINSOCK2_H
 #    include <winsock2.h>
 #  endif
+#  include <ws2tcpip.h>
 #  include <windows.h>
 #  include <process.h>
 #endif
@@ -165,33 +170,53 @@
 /* ************************************************************************ */
 /* Macros that let us use IPv6                                              */
 
-#if defined(HAVE_IN6) && defined(AF_INET6) && defined(EPMD6)
+#if HAVE_IN6
+#  if ! defined(HAVE_IN6ADDR_ANY) || ! HAVE_IN6ADDR_ANY
+#    if HAVE_DECL_IN6ADDR_ANY_INIT
+static const struct in6_addr in6addr_any = { { IN6ADDR_ANY_INIT } };
+#    else
+static const struct in6_addr in6addr_any =
+    { { { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } } };
+#    endif /* HAVE_IN6ADDR_ANY_INIT */
+#  endif /* ! HAVE_DECL_IN6ADDR_ANY */
+
+#  if ! defined(HAVE_IN6ADDR_LOOPBACK) || ! HAVE_IN6ADDR_LOOPBACK
+#    if HAVE_DECL_IN6ADDR_LOOPBACK_INIT
+static const struct in6_addr in6addr_loopback =
+    { { IN6ADDR_LOOPBACK_INIT } };
+#    else
+static const struct in6_addr in6addr_loopback =
+    { { { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1 } } };
+#    endif /* HAVE_IN6ADDR_LOOPBACK_INIT */
+#  endif /* ! HAVE_DECL_IN6ADDR_LOOPBACK */
+#endif /* HAVE_IN6 */
+
+#define IS_ADDR_LOOPBACK(addr) ((addr).s_addr == htonl(INADDR_LOOPBACK))
+
+#if defined(HAVE_IN6) && defined(AF_INET6)
 
-#define EPMD_SOCKADDR_IN sockaddr_in6
-#define EPMD_IN_ADDR in6_addr
-#define EPMD_S_ADDR s6_addr
-#define EPMD_ADDR_LOOPBACK in6addr_loopback.s6_addr
-#define EPMD_ADDR_ANY in6addr_any.s6_addr
+#define EPMD_SOCKADDR_IN sockaddr_storage
 #define FAMILY AF_INET6
 
-#define SET_ADDR(dst, addr, port) do { \
-    memset((char*)&(dst), 0, sizeof(dst)); \
-    memcpy((char*)&(dst).sin6_addr.s6_addr, (char*)&(addr), 16); \
-    (dst).sin6_family = AF_INET6; \
-    (dst).sin6_flowinfo = 0; \
-    (dst).sin6_port = htons(port); \
+#define SET_ADDR6(dst, addr, port) do { \
+    struct sockaddr_in6 *sa = (struct sockaddr_in6 *)&(dst); \
+    memset(sa, 0, sizeof(dst)); \
+    sa->sin6_family = AF_INET6; \
+    sa->sin6_addr = (addr); \
+    sa->sin6_port = htons(port); \
  } while(0)
 
-#define IS_ADDR_LOOPBACK(addr) \
-    (memcmp((addr).s6_addr, in6addr_loopback.s6_addr, 16) == 0)
+#define SET_ADDR(dst, addr, port) do { \
+    struct sockaddr_in *sa = (struct sockaddr_in *)&(dst); \
+    memset(sa, 0, sizeof(dst)); \
+    sa->sin_family = AF_INET; \
+    sa->sin_addr.s_addr = (addr); \
+    sa->sin_port = htons(port); \
+ } while(0)
 
 #else /* Not IP v6 */
 
 #define EPMD_SOCKADDR_IN sockaddr_in
-#define EPMD_IN_ADDR in_addr
-#define EPMD_S_ADDR s_addr
-#define EPMD_ADDR_LOOPBACK htonl(INADDR_LOOPBACK)
-#define EPMD_ADDR_ANY htonl(INADDR_ANY)
 #define FAMILY AF_INET
 
 #define SET_ADDR(dst, addr, port) do { \
@@ -201,8 +226,6 @@
     (dst).sin_port = htons(port); \
  } while(0)
 
-#define IS_ADDR_LOOPBACK(addr) ((addr).s_addr == htonl(INADDR_LOOPBACK))
-
 #endif /* Not IP v6 */
 
 /* ************************************************************************ */