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, 142 insertions, 59 deletions

diff --git a/erts/epmd/src/epmd_srv.c b/erts/epmd/src/epmd_srv.c
index 7100855407..55ec0f7b6c 100644
--- a/erts/epmd/src/epmd_srv.c
+++ b/erts/epmd/src/epmd_srv.c
@@ -76,6 +76,7 @@ static time_t current_time(EpmdVars*);
 
 static Connection *conn_init(EpmdVars*);
 static int conn_open(EpmdVars*,int);
+static int conn_local_peer_check(EpmdVars*, int);
 static int conn_close_fd(EpmdVars*,int);
 
 static void node_init(EpmdVars*);
@@ -206,10 +207,11 @@ void run(EpmdVars *g)
 {
   struct EPMD_SOCKADDR_IN iserv_addr[MAX_LISTEN_SOCKETS];
   int listensock[MAX_LISTEN_SOCKETS];
-  int num_sockets;
+  int num_sockets = 0;
   int i;
   int opt;
   unsigned short sport = g->port;
+  int bound = 0;
 
   node_init(g);
   g->conn = conn_init(g);
@@ -252,64 +254,82 @@ void run(EpmdVars *g)
   if (g->addresses != NULL && /* String contains non-separator characters if: */
       g->addresses[strspn(g->addresses," ,")] != '\000')
     {
-      char *tmp;
-      char *token;
-      int loopback_ok = 0;
+      char *tmp = NULL;
+      char *token = NULL;
+
+      /* Always listen on the loopback. */
+      SET_ADDR(iserv_addr[num_sockets],htonl(INADDR_LOOPBACK),sport);
+      num_sockets++;
+#if defined(EPMD6)
+      SET_ADDR6(iserv_addr[num_sockets],in6addr_loopback,sport);
+      num_sockets++;
+#endif
 
-      if ((tmp = (char *)malloc(strlen(g->addresses) + 1)) == NULL)
+	  if ((tmp = strdup(g->addresses)) == NULL)
 	{
 	  dbg_perror(g,"cannot allocate memory");
 	  epmd_cleanup_exit(g,1);
 	}
-      strcpy(tmp,g->addresses);
 
-      for(token = strtok(tmp,", "), num_sockets = 0;
+      for(token = strtok(tmp,", ");
 	  token != NULL;
-	  token = strtok(NULL,", "), num_sockets++)
+	  token = strtok(NULL,", "))
 	{
-	  struct EPMD_IN_ADDR addr;
-#ifdef HAVE_INET_PTON
-	  int ret;
+	  struct in_addr addr;
+#if defined(EPMD6)
+	  struct in6_addr addr6;
+	  struct sockaddr_storage *sa = &iserv_addr[num_sockets];
 
-	  if ((ret = inet_pton(FAMILY,token,&addr)) == -1)
+	  if (inet_pton(AF_INET6,token,&addr6) == 1)
 	    {
-	      dbg_perror(g,"cannot convert IP address to network format");
-	      epmd_cleanup_exit(g,1);
+	      SET_ADDR6(iserv_addr[num_sockets],addr6,sport);
+	    }
+	  else if (inet_pton(AF_INET,token,&addr) == 1)
+	    {
+	      SET_ADDR(iserv_addr[num_sockets],addr.s_addr,sport);
+	    }
+	  else
+#else
+	  if ((addr.s_addr = inet_addr(token)) != INADDR_NONE)
+	    {
+	      SET_ADDR(iserv_addr[num_sockets],addr.s_addr,sport);
 	    }
-	  else if (ret == 0)
-#elif !defined(EPMD6)
-	  if ((addr.EPMD_S_ADDR = inet_addr(token)) == INADDR_NONE)
+	  else
 #endif
 	    {
 	      dbg_tty_printf(g,0,"cannot parse IP address \"%s\"",token);
 	      epmd_cleanup_exit(g,1);
 	    }
 
+#if defined(EPMD6)
+	  if (sa->ss_family == AF_INET6 && IN6_IS_ADDR_LOOPBACK(&addr6))
+	      continue;
+
+	  if (sa->ss_family == AF_INET)
+#endif
 	  if (IS_ADDR_LOOPBACK(addr))
-	    loopback_ok = 1;
+	    continue;
+
+	  num_sockets++;
 
-	  if (num_sockets - loopback_ok == MAX_LISTEN_SOCKETS - 1)
+	  if (num_sockets >= MAX_LISTEN_SOCKETS)
 	    {
 	      dbg_tty_printf(g,0,"cannot listen on more than %d IP addresses",
 			     MAX_LISTEN_SOCKETS);
 	      epmd_cleanup_exit(g,1);
 	    }
-
-	  SET_ADDR(iserv_addr[num_sockets],addr.EPMD_S_ADDR,sport);
 	}
 
       free(tmp);
-
-      if (!loopback_ok)
-	{
-	  SET_ADDR(iserv_addr[num_sockets],EPMD_ADDR_LOOPBACK,sport);
-	  num_sockets++;
-	}
     }
   else
     {
-      SET_ADDR(iserv_addr[0],EPMD_ADDR_ANY,sport);
-      num_sockets = 1;
+      SET_ADDR(iserv_addr[num_sockets],htonl(INADDR_ANY),sport);
+      num_sockets++;
+#if defined(EPMD6)
+      SET_ADDR6(iserv_addr[num_sockets],in6addr_any,sport);
+      num_sockets++;
+#endif
     }
 #ifdef HAVE_SYSTEMD_DAEMON
     }
@@ -340,13 +360,39 @@ void run(EpmdVars *g)
 #endif /* HAVE_SYSTEMD_DAEMON */
   for (i = 0; i < num_sockets; i++)
     {
-      if ((listensock[i] = socket(FAMILY,SOCK_STREAM,0)) < 0)
+      struct sockaddr *sa = (struct sockaddr *)&iserv_addr[i];
+#if defined(EPMD6)
+      size_t salen = (sa->sa_family == AF_INET6 ?
+              sizeof(struct sockaddr_in6) :
+              sizeof(struct sockaddr_in));
+#else
+      size_t salen = sizeof(struct sockaddr_in);
+#endif
+
+      if ((listensock[i] = socket(sa->sa_family,SOCK_STREAM,0)) < 0)
 	{
-	  dbg_perror(g,"error opening stream socket");
-	  epmd_cleanup_exit(g,1);
+	  switch (errno) {
+	      case EAFNOSUPPORT:
+	      case EPROTONOSUPPORT:
+	          continue;
+	      default:
+	          dbg_perror(g,"error opening stream socket");
+	          epmd_cleanup_exit(g,1);
+	  }
 	}
       g->listenfd[i] = listensock[i];
-  
+
+#if HAVE_DECL_IPV6_V6ONLY
+      opt = 1;
+      if (sa->sa_family == AF_INET6 &&
+          setsockopt(listensock[i],IPPROTO_IPV6,IPV6_V6ONLY,&opt,
+              sizeof(opt)) <0)
+	{
+	  dbg_perror(g,"can't set IPv6 only socket option");
+	  epmd_cleanup_exit(g,1);
+	}
+#endif
+
       /*
        * Note that we must not enable the SO_REUSEADDR on Windows,
        * because addresses will be reused even if they are still in use.
@@ -378,8 +424,7 @@ void run(EpmdVars *g)
 	dbg_perror(g,"failed to set non-blocking mode of listening socket %d",
 		   listensock[i]);
 
-      if (bind(listensock[i], (struct sockaddr*) &iserv_addr[i],
-	  sizeof(iserv_addr[i])) < 0)
+      if (bind(listensock[i], (struct sockaddr*) &iserv_addr[i], salen) < 0)
 	{
 	  if (errno == EADDRINUSE)
 	    {
@@ -394,12 +439,18 @@ void run(EpmdVars *g)
 	    }
 	}
 
+      bound++;
+
       if(listen(listensock[i], SOMAXCONN) < 0) {
           dbg_perror(g,"failed to listen on socket");
           epmd_cleanup_exit(g,1);
       }
       select_fd_set(g, listensock[i]);
     }
+  if (bound == 0) {
+      dbg_perror(g,"unable to bind any address");
+      epmd_cleanup_exit(g,1);
+  }
 #ifdef HAVE_SYSTEMD_DAEMON
     }
     sd_notifyf(0, "READY=1\n"
@@ -1005,15 +1056,6 @@ 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;
-#ifdef HAVE_SOCKLEN_T
-      socklen_t st;
-#else
-      int st;
-#endif
-      st = sizeof(si);
-
       g->active_conn++;
       s = &g->conn[i];
      
@@ -1024,20 +1066,7 @@ static int conn_open(EpmdVars *g,int fd)
       s->open = EPMD_TRUE;
       s->keep = EPMD_FALSE;
 
-      /* Determine if connection is from localhost */
-      if (getpeername(s->fd,(struct sockaddr*) &si,&st) ||
-	  st < sizeof(si)) {
-	  /* 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));
-      }
+      s->local_peer = conn_local_peer_check(g, s->fd);
       dbg_tty_printf(g,2,(s->local_peer) ? "Local peer connected" :
 		     "Non-local peer connected");
 
@@ -1045,7 +1074,7 @@ static int conn_open(EpmdVars *g,int fd)
       s->got  = 0;
       s->mod_time = current_time(g); /* Note activity */
 
-      s->buf = (char *)malloc(INBUF_SIZE);
+      s->buf = malloc(INBUF_SIZE);
 
       if (s->buf == NULL) {
 	dbg_printf(g,0,"epmd: Insufficient memory");
@@ -1063,6 +1092,60 @@ static int conn_open(EpmdVars *g,int fd)
   return EPMD_FALSE;
 }
 
+static int conn_local_peer_check(EpmdVars *g, int fd)
+{
+  struct EPMD_SOCKADDR_IN si;
+  struct EPMD_SOCKADDR_IN di;
+
+  struct sockaddr_in *si4 = (struct sockaddr_in *)&si;
+  struct sockaddr_in *di4 = (struct sockaddr_in *)&di;
+
+#if defined(EPMD6)
+  struct sockaddr_in6 *si6 = (struct sockaddr_in6 *)&si;
+  struct sockaddr_in6 *di6 = (struct sockaddr_in6 *)&di;
+#endif
+
+#ifdef HAVE_SOCKLEN_T
+  socklen_t st;
+#else
+  int st;
+#endif
+
+  st = sizeof(si);
+
+  /* Determine if connection is from localhost */
+  if (getpeername(fd,(struct sockaddr*) &si,&st) ||
+	  st > sizeof(si)) {
+	  /* Failure to get peername is regarded as non local host */
+	  return EPMD_FALSE;
+  }
+
+  /* Only 127.x.x.x and connections from the host's IP address
+	 allowed, no false positives */
+#if defined(EPMD6)
+  if (si.ss_family == AF_INET6 && IN6_IS_ADDR_LOOPBACK(&(si6->sin6_addr)))
+	  return EPMD_TRUE;
+
+  if (si.ss_family == AF_INET)
+#endif
+  if ((((unsigned) ntohl(si4->sin_addr.s_addr)) & 0xFF000000U) ==
+	  0x7F000000U)
+	  return EPMD_TRUE;
+
+  if (getsockname(fd,(struct sockaddr*) &di,&st))
+	  return EPMD_FALSE;
+
+#if defined(EPMD6)
+  if (si.ss_family == AF_INET6)
+      return IN6_ARE_ADDR_EQUAL( &(si6->sin6_addr), &(di6->sin6_addr));
+  if (si.ss_family == AF_INET)
+#endif
+  return si4->sin_addr.s_addr == di4->sin_addr.s_addr;
+#if defined(EPMD6)
+  return EPMD_FALSE;
+#endif
+}
+
 static int conn_close_fd(EpmdVars *g,int fd)
 {
   int i;