ng_ether: track interface renaming

Also sanitize interface names that can potentially contain characters
that are prohibited in netgraph names.

PR:		kern/154850 (sanitizing of names)
Discussed with:	eri, melifaro
Submitted by:	Nikolay Denev <ndenev@gmail.com> (sanitizing code)
Reviewed by:	eri, glebius
MFC after:	17 days

sys/netgraph/ng_ether.c

@@ -117,6 +117,8 @@ static ng_rcvdata_t	ng_ether_rcvdata;
 static ng_disconnect_t	ng_ether_disconnect;
 static int		ng_ether_mod_event(module_t mod, int event, void *data);
 
+static eventhandler_tag	ng_ether_ifnet_arrival_cookie;
+
 /* List of commands and how to convert arguments to/from ASCII */
 static const struct ng_cmdlist ng_ether_cmdlist[] = {
 	{
@@ -213,6 +215,24 @@ static struct ng_type ng_ether_typestruct = {
 };
 NETGRAPH_INIT(ether, &ng_ether_typestruct);
 
+/******************************************************************
+		    UTILITY FUNCTIONS
+******************************************************************/
+static void
+ng_ether_sanitize_ifname(const char *ifname, char *name)
+{
+	int i;
+
+	for (i = 0; i < IFNAMSIZ; i++) {
+		if (ifname[i] == '.' || ifname[i] == ':')
+			name[i] = '_';
+		else
+			name[i] = ifname[i];
+		if (name[i] == '\0')
+			break;
+	}
+}
+
 /******************************************************************
 		    ETHERNET FUNCTION HOOKS
 ******************************************************************/
@@ -282,6 +302,7 @@ ng_ether_output(struct ifnet *ifp, struct mbuf **mp)
 static void
 ng_ether_attach(struct ifnet *ifp)
 {
+	char name[IFNAMSIZ];
 	priv_p priv;
 	node_p node;
 
@@ -319,10 +340,9 @@ ng_ether_attach(struct ifnet *ifp)
 	priv->hwassist = ifp->if_hwassist;
 
 	/* Try to give the node the same name as the interface */
-	if (ng_name_node(node, ifp->if_xname) != 0) {
+	ng_ether_sanitize_ifname(ifp->if_xname, name);
-		log(LOG_WARNING, "%s: can't name node %s\n",
+	if (ng_name_node(node, name) != 0)
-		    __func__, ifp->if_xname);
+		log(LOG_WARNING, "%s: can't name node %s\n", __func__, name);
-	}
 }
 
 /*
@@ -378,6 +398,32 @@ ng_ether_link_state(struct ifnet *ifp, int state)
 	}
 }
 
+/*
+ * Interface arrival notification handler.
+ * The notification is produced in two cases:
+ *  o a new interface arrives
+ *  o an existing interface got renamed
+ * Currently the first case is handled by ng_ether_attach via special
+ * hook ng_ether_attach_p.
+ */
+static void
+ng_ether_ifnet_arrival_event(void *arg __unused, struct ifnet *ifp)
+{
+	char name[IFNAMSIZ];
+	node_p node = IFP2NG(ifp);
+
+	/*
+	 * Just return if it's a new interface without an ng_ether companion.
+	 */
+	if (node == NULL)
+		return;
+
+	/* Try to give the node the same name as the new interface name */
+	ng_ether_sanitize_ifname(ifp->if_xname, name);
+	if (ng_name_node(node, name) != 0)
+		log(LOG_WARNING, "%s: can't re-name node %s\n", __func__, name);
+}
+
 /******************************************************************
 		    NETGRAPH NODE METHODS
 ******************************************************************/
@@ -771,6 +817,9 @@ ng_ether_mod_event(module_t mod, int event, void *data)
 		ng_ether_input_orphan_p = ng_ether_input_orphan;
 		ng_ether_link_state_p = ng_ether_link_state;
 
+		ng_ether_ifnet_arrival_cookie =
+		    EVENTHANDLER_REGISTER(ifnet_arrival_event,
+		    ng_ether_ifnet_arrival_event, NULL, EVENTHANDLER_PRI_ANY);
 		break;
 
 	case MOD_UNLOAD:
@@ -783,6 +832,9 @@ ng_ether_mod_event(module_t mod, int event, void *data)
 		 * is MOD_UNLOAD, so there's no need to detach any nodes.
 		 */
 
+		EVENTHANDLER_DEREGISTER(ifnet_arrival_event,
+		    ng_ether_ifnet_arrival_cookie);
+
 		/* Unregister function hooks */
 		ng_ether_attach_p = NULL;
 		ng_ether_detach_p = NULL;