Extend /4 and /6 syntax to --interface-name

man/dnsmasq.8

@@ -514,11 +514,13 @@ record (which is always in the C_IN class). The value of the record is
 given by the hex data, which may be of the form 01:23:45 or 01 23 45 or
 012345 or any mixture of these.
 .TP
-.B --interface-name=<name>,<interface>
+.B --interface-name=<name>,<interface>[/4|/6]
 Return a DNS record associating the name with the primary address on
-the given interface. This flag specifies an A record for the given
+the given interface. This flag specifies an A or AAAA record for the given
 name in the same way as an /etc/hosts line, except that the address is
-not constant, but taken from the given interface. If the interface is
+not constant, but taken from the given interface. The interface may be
+followed by "/4" or "/6" to specify that only IPv4 or IPv6 addresses
+of the interface should be used. If the interface is
 down, not configured or non-existent, an empty record is returned. The
 matching PTR record is also created, mapping the interface address to
 the name. More than one name may be associated with an interface

src/dnsmasq.c

@@ -636,7 +636,10 @@ int main (int argc, char **argv)
   if (bind_fallback)
     my_syslog(LOG_WARNING, _("setting --bind-interfaces option because of OS limitations"));
 
-  warn_bound_listeners();
+  if (option_bool(OPT_NOWILD))
+    warn_bound_listeners();
+
+  warn_int_names();
   
   if (!option_bool(OPT_NOWILD)) 
     for (if_tmp = daemon->if_names; if_tmp; if_tmp = if_tmp->next)

src/dnsmasq.h

@@ -321,6 +321,7 @@ struct host_record {
 struct interface_name {
   char *name; /* domain name */
   char *intr; /* interface name */
+  int family; /* AF_INET, AF_INET6 or zero for both */
   struct addrlist *addr;
   struct interface_name *next;
 };
@@ -1076,6 +1077,7 @@ int enumerate_interfaces(int reset);
 void create_wildcard_listeners(void);
 void create_bound_listeners(int die);
 void warn_bound_listeners(void);
+void warn_int_names(void);
 int is_dad_listeners(void);
 int iface_check(int family, struct all_addr *addr, char *name, int *auth_dns);
 int loopback_exception(int fd, int family, struct all_addr *addr, char *name);

src/network.c

@@ -330,7 +330,8 @@ static int iface_allowed(struct iface_param *param, int if_index, char *label,
       /* Update addresses from interface_names. These are a set independent
 	 of the set we're listening on. */  
       for (int_name = daemon->int_names; int_name; int_name = int_name->next)
-	if (strncmp(label, int_name->intr, IF_NAMESIZE) == 0)
+	if (strncmp(label, int_name->intr, IF_NAMESIZE) == 0 && 
+	    (addr->sa.sa_family == int_name->family || int_name->family == 0))
 	  {
 	    if (param->spare)
 	      {
@@ -915,7 +916,7 @@ void warn_bound_listeners(void)
   int advice = 0;
 
   for (iface = daemon->interfaces; iface; iface = iface->next)
-    if (option_bool(OPT_NOWILD) && !iface->dns_auth)
+    if (!iface->dns_auth)
       {
 	int warn = 0;
 	if (iface->addr.sa.sa_family == AF_INET)
@@ -943,15 +944,24 @@ void warn_bound_listeners(void)
 	  {
 	    iface->warned = advice = 1;
 	    my_syslog(LOG_WARNING, 
-		      _("LOUD WARNING: listening on %s may accept requests via interfaces other than %s. "),
+		      _("LOUD WARNING: listening on %s may accept requests via interfaces other than %s"),
 		      daemon->addrbuff, iface->name);
 	  }
       }
   
   if (advice)
-    my_syslog(LOG_WARNING, _("LOUD WARNING: use --bind-dynamic rather than --bind-interfaces to avoid DNS amplification attacks via these interface(s).")); 
+    my_syslog(LOG_WARNING, _("LOUD WARNING: use --bind-dynamic rather than --bind-interfaces to avoid DNS amplification attacks via these interface(s)")); 
 }
 
+void warn_int_names(void)
+{
+  struct interface_name *intname;
+ 
+  for (intname = daemon->int_names; intname; intname = intname->next)
+    if (!intname->addr)
+      my_syslog(LOG_WARNING, _("warning: no addresses found for interface %s"), intname->intr);
+}
+ 
 int is_dad_listeners(void)
 {
   struct irec *iface;

src/option.c

@@ -3376,6 +3376,19 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	for (up = &daemon->int_names; *up; up = &((*up)->next));
 	*up = new;
 	new->name = domain;
+	new->family = 0;
+	arg = split_chr(comma, '/');
+	if (arg)
+	  {
+	    if (strcmp(arg, "4") == 0)
+	      new->family = AF_INET;
+#ifdef HAVE_IPV6
+	    else if (strcmp(arg, "6") == 0)
+	      new->family = AF_INET6;
+#endif
+	    else
+	      ret_err(gen_err);
+	  } 
 	new->intr = opt_string_alloc(comma);
 	break;
       }