dummy: fixed to use overlooked numdummies=0 option

This avoids the bugs and races caused by the workaround
attempt in commit 45c698f of pull request #511 / 0.6.16.

src/ifconfig.c

@@ -89,10 +89,12 @@
 #ifndef TUNNEL4_MODULE_NAME
 #define TUNNEL4_MODULE_NAME "tunnel4"
 #endif
-
 #ifndef DUMMY_MODULE_NAME
 #define DUMMY_MODULE_NAME "dummy"
 #endif
+#ifndef DUMMY_MODULE_OPTS
+#define DUMMY_MODULE_OPTS "numdummies=0"
+#endif
 
 static int	__ni_netdev_update_addrs(ni_netdev_t *dev,
 				const ni_addrconf_lease_t *old_lease,
@@ -109,7 +111,6 @@ static int	__ni_rtnl_link_change(ni_netdev_t *dev, const ni_netdev_t *cfg);
 
 static int	__ni_rtnl_link_change_mtu(ni_netdev_t *dev, unsigned int mtu);
 static int	__ni_rtnl_link_change_hwaddr(ni_netdev_t *dev, const ni_hwaddr_t *hwaddr);
-static int	__ni_rtnl_link_rename(unsigned int ifindex, const char *oldname, const char *newname);
 
 static int	__ni_rtnl_link_up(const ni_netdev_t *, const ni_netdev_req_t *);
 static int	__ni_rtnl_link_down(const ni_netdev_t *);
@@ -858,7 +859,6 @@ int
 ni_system_dummy_create(ni_netconfig_t *nc, const ni_netdev_t *cfg,
 						ni_netdev_t **dev_ret)
 {
-	unsigned int dummy0[2] = { 0, 0 };
 	ni_netdev_t *dev;
 	int err;
 
@@ -881,42 +881,8 @@ ni_system_dummy_create(ni_netconfig_t *nc, const ni_netdev_t *cfg,
 		return -NI_ERROR_DEVICE_EXISTS;
 	}
 
-	if (!dummy0[0] && ni_modprobe(DUMMY_MODULE_NAME, NULL) < 0)
-			ni_warn("failed to load %s module", DUMMY_MODULE_NAME);
-
-	dummy0[1] = if_nametoindex("dummy0");
-	if (dummy0[1] && !dummy0[0]) {
-		ni_debug_ifconfig("%s: using modprobe created dummy0[%u]",
-				cfg->name, dummy0[1]);
-
-		if (!ni_string_eq("dummy0", cfg->name)) {
-			if ((err = __ni_rtnl_link_rename(dummy0[1], "dummy0", cfg->name)) < 0)
-				return err;
-		}
-
-		if (!(dev = ni_netdev_new(cfg->name, dummy0[1]))) {
-			ni_error("%s: unable to allocate %s netdev structure for index %u: %m",
-				cfg->name, "dummy", dummy0[1]);
-			return -1;
-		}
-
-		__ni_device_refresh_link_info(nc, &dev->link);
-		dev->created = 1;
-		dev->link.ifflags &= ~(NI_IFF_DEVICE_UP | NI_IFF_LINK_UP | NI_IFF_NETWORK_UP);
-		ni_netconfig_device_append(nc, ni_netdev_get(dev));
-
-		*dev_ret = dev;
-		if (dev->link.type != NI_IFTYPE_DUMMY) {
-			ni_error("%s: created %s interface, but found a %s type at index %u",
-				cfg->name, "dummy", ni_linktype_type_to_name(dev->link.type),
-				dummy0[1]);
-			return -NI_ERROR_DEVICE_EXISTS;
-		}
-		ni_debug_ifconfig("%s: created %s interface with index %u",
-			dev->name, ni_linktype_type_to_name(dev->link.type),
-			dev->link.ifindex);
-		return 0;
-	}
+	if (ni_modprobe(DUMMY_MODULE_NAME, DUMMY_MODULE_OPTS) < 0)
+		ni_warn("failed to load %s network driver module", DUMMY_MODULE_NAME);
 
 	ni_debug_ifconfig("%s: creating dummy interface", cfg->name);
 

src/kernel.h

@@ -66,6 +66,7 @@ extern int		__ni_tuntap_create(const ni_netdev_t *);
 extern char *		__ni_ppp_create_device(ni_ppp_t *, const char *);
 
 extern int		__ni_netdev_rename(const char *old_name, const char *new_name);
+extern int		__ni_rtnl_link_rename(unsigned int ifindex, const char *oldname, const char *newname);
 
 extern const void *	__ni_nla_get_data(size_t, const struct nlattr *);
 extern int		__ni_nla_get_addr(int, ni_sockaddr_t *, const struct nlattr *);