chiark / gitweb /
networkd: route/address - use trivial hash functions
[elogind.git] / src / network / networkd-netdev.c
index 356341a8735817c20e7c99427fe0674e9f446834..4a6f6e3475e3f52478a20b18660698bc18582c1c 100644 (file)
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#include "networkd.h"
+#include <net/if.h>
+
+#include "networkd-netdev.h"
 #include "network-internal.h"
 #include "path-util.h"
 #include "conf-files.h"
 #include "conf-parser.h"
 #include "list.h"
-
-#define VLANID_MAX 4094
+#include "siphash24.h"
+
+const NetDevVTable * const netdev_vtable[_NETDEV_KIND_MAX] = {
+        [NETDEV_KIND_BRIDGE] = &bridge_vtable,
+        [NETDEV_KIND_BOND] = &bond_vtable,
+        [NETDEV_KIND_VLAN] = &vlan_vtable,
+        [NETDEV_KIND_MACVLAN] = &macvlan_vtable,
+        [NETDEV_KIND_VXLAN] = &vxlan_vtable,
+        [NETDEV_KIND_IPIP] = &ipip_vtable,
+        [NETDEV_KIND_GRE] = &gre_vtable,
+        [NETDEV_KIND_SIT] = &sit_vtable,
+        [NETDEV_KIND_VTI] = &vti_vtable,
+        [NETDEV_KIND_VETH] = &veth_vtable,
+        [NETDEV_KIND_DUMMY] = &dummy_vtable,
+        [NETDEV_KIND_TUN] = &tun_vtable,
+        [NETDEV_KIND_TAP] = &tap_vtable,
+};
 
 static const char* const netdev_kind_table[_NETDEV_KIND_MAX] = {
         [NETDEV_KIND_BRIDGE] = "bridge",
         [NETDEV_KIND_BOND] = "bond",
         [NETDEV_KIND_VLAN] = "vlan",
         [NETDEV_KIND_MACVLAN] = "macvlan",
+        [NETDEV_KIND_VXLAN] = "vxlan",
+        [NETDEV_KIND_IPIP] = "ipip",
+        [NETDEV_KIND_GRE] = "gre",
+        [NETDEV_KIND_SIT] = "sit",
+        [NETDEV_KIND_VETH] = "veth",
+        [NETDEV_KIND_VTI] = "vti",
+        [NETDEV_KIND_DUMMY] = "dummy",
+        [NETDEV_KIND_TUN] = "tun",
+        [NETDEV_KIND_TAP] = "tap",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(netdev_kind, NetDevKind);
 DEFINE_CONFIG_PARSE_ENUM(config_parse_netdev_kind, netdev_kind, NetDevKind, "Failed to parse netdev kind");
 
-static const char* const macvlan_mode_table[_NETDEV_MACVLAN_MODE_MAX] = {
-        [NETDEV_MACVLAN_MODE_PRIVATE] = "private",
-        [NETDEV_MACVLAN_MODE_VEPA] = "vepa",
-        [NETDEV_MACVLAN_MODE_BRIDGE] = "bridge",
-        [NETDEV_MACVLAN_MODE_PASSTHRU] = "passthru",
-};
-
-DEFINE_STRING_TABLE_LOOKUP(macvlan_mode, MacVlanMode);
-DEFINE_CONFIG_PARSE_ENUM(config_parse_macvlan_mode, macvlan_mode, MacVlanMode, "Failed to parse macvlan mode");
 
-void netdev_free(NetDev *netdev) {
-        netdev_enslave_callback *callback;
+static void netdev_cancel_callbacks(NetDev *netdev) {
+        _cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
+        netdev_join_callback *callback;
 
         if (!netdev)
                 return;
 
+        rtnl_message_new_synthetic_error(-ENODEV, 0, &m);
+
         while ((callback = netdev->callbacks)) {
+                if (m) {
+                        assert(callback->link);
+                        assert(callback->callback);
+                        assert(netdev->manager);
+                        assert(netdev->manager->rtnl);
+
+                        callback->callback(netdev->manager->rtnl, m, link);
+                }
+
                 LIST_REMOVE(callbacks, netdev->callbacks, callback);
                 free(callback);
         }
+}
 
-        if (netdev->name)
-                hashmap_remove(netdev->manager->netdevs, netdev->name);
+static void netdev_free(NetDev *netdev) {
+        if (!netdev)
+                return;
+
+        netdev_cancel_callbacks(netdev);
+
+        if (netdev->ifname)
+                hashmap_remove(netdev->manager->netdevs, netdev->ifname);
 
         free(netdev->filename);
 
         free(netdev->description);
-        free(netdev->name);
+        free(netdev->ifname);
+        free(netdev->mac);
+
+        condition_free_list(netdev->match_host);
+        condition_free_list(netdev->match_virt);
+        condition_free_list(netdev->match_kernel);
+        condition_free_list(netdev->match_arch);
+
+        if (NETDEV_VTABLE(netdev) &&
+            NETDEV_VTABLE(netdev)->done)
+                NETDEV_VTABLE(netdev)->done(netdev);
 
         free(netdev);
 }
 
+NetDev *netdev_unref(NetDev *netdev) {
+        if (netdev && (-- netdev->n_ref <= 0))
+                netdev_free(netdev);
+
+        return NULL;
+}
+
+NetDev *netdev_ref(NetDev *netdev) {
+        if (netdev)
+                assert_se(++ netdev->n_ref >= 2);
+
+        return netdev;
+}
+
+void netdev_drop(NetDev *netdev) {
+        if (!netdev || netdev->state == NETDEV_STATE_LINGER)
+                return;
+
+        netdev->state = NETDEV_STATE_LINGER;
+
+        log_debug_netdev(netdev, "netdev removed");
+
+        netdev_cancel_callbacks(netdev);
+
+        netdev_unref(netdev);
+
+        return;
+}
+
 int netdev_get(Manager *manager, const char *name, NetDev **ret) {
         NetDev *netdev;
 
@@ -102,6 +177,7 @@ static int netdev_enslave_ready(NetDev *netdev, Link* link, sd_rtnl_message_hand
         assert(netdev->state == NETDEV_STATE_READY);
         assert(netdev->manager);
         assert(netdev->manager->rtnl);
+        assert(IN_SET(netdev->kind, NETDEV_KIND_BRIDGE, NETDEV_KIND_BOND));
         assert(link);
         assert(callback);
 
@@ -130,312 +206,394 @@ static int netdev_enslave_ready(NetDev *netdev, Link* link, sd_rtnl_message_hand
                 return r;
         }
 
+        link_ref(link);
+
         log_debug_netdev(netdev, "enslaving link '%s'", link->ifname);
 
         return 0;
 }
 
 static int netdev_enter_ready(NetDev *netdev) {
-        netdev_enslave_callback *callback;
+        netdev_join_callback *callback, *callback_next;
+        int r;
 
         assert(netdev);
-        assert(netdev->name);
+        assert(netdev->ifname);
+
+        if (netdev->state != NETDEV_STATE_CREATING)
+                return 0;
 
         netdev->state = NETDEV_STATE_READY;
 
         log_info_netdev(netdev, "netdev ready");
 
-        LIST_FOREACH(callbacks, callback, netdev->callbacks) {
-                /* enslave the links that were attempted to be enslaved befor the
+        LIST_FOREACH_SAFE(callbacks, callback, callback_next, netdev->callbacks) {
+                /* enslave the links that were attempted to be enslaved before the
                  * link was ready */
-                netdev_enslave_ready(netdev, callback->link, callback->callback);
+                r = netdev_enslave_ready(netdev, callback->link, callback->callback);
+                if (r < 0)
+                        return r;
+
+                LIST_REMOVE(callbacks, netdev->callbacks, callback);
+                link_unref(callback->link);
+                free(callback);
         }
 
         return 0;
 }
 
-static int netdev_getlink_handler(sd_rtnl *rtnl, sd_rtnl_message *m,
-                                void *userdata) {
-        NetDev *netdev = userdata;
+/* callback for netdev's created without a backing Link */
+static int netdev_create_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
+        _cleanup_netdev_unref_ NetDev *netdev = userdata;
         int r;
 
-        assert(netdev);
-
-        if (netdev->state == NETDEV_STATE_FAILED)
-                return 1;
+        assert(netdev->state != _NETDEV_STATE_INVALID);
 
         r = sd_rtnl_message_get_errno(m);
-        if (r < 0) {
-                log_struct_netdev(LOG_ERR, netdev,
-                                "MESSAGE=%s: could not get link: %s",
-                                netdev->name, strerror(-r),
-                                "ERRNO=%d", -r,
-                                NULL);
+        if (r == -EEXIST)
+                log_debug_netdev(netdev, "netdev exists, using existing");
+        else if (r < 0) {
+                log_warning_netdev(netdev, "netdev could not be created: %s", strerror(-r));
+                netdev_drop(netdev);
+
                 return 1;
         }
 
-        netdev_set_ifindex(netdev, m);
+        log_debug_netdev(netdev, "created");
 
         return 1;
 }
 
-static int netdev_getlink(NetDev *netdev) {
-        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
+int netdev_enslave(NetDev *netdev, Link *link, sd_rtnl_message_handler_t callback) {
         int r;
 
-        assert(netdev->manager);
-        assert(netdev->manager->rtnl);
-        assert(netdev->name);
+        assert(netdev);
+        assert(IN_SET(netdev->kind, NETDEV_KIND_BRIDGE, NETDEV_KIND_BOND));
+
+        if (netdev->state == NETDEV_STATE_READY) {
+                r = netdev_enslave_ready(netdev, link, callback);
+                if (r < 0)
+                        return r;
+        } else {
+                /* the netdev is not yet read, save this request for when it is*/
+                netdev_join_callback *cb;
 
-        log_debug_netdev(netdev, "requesting netdev status");
+                cb = new0(netdev_join_callback, 1);
+                if (!cb)
+                        return log_oom();
 
-        r = sd_rtnl_message_new_link(netdev->manager->rtnl, &req,
-                                     RTM_GETLINK, 0);
-        if (r < 0) {
-                log_error_netdev(netdev, "Could not allocate RTM_GETLINK message");
-                return r;
-        }
+                cb->callback = callback;
+                cb->link = link;
+                link_ref(link);
 
-        r = sd_rtnl_message_append_string(req, IFLA_IFNAME, netdev->name);
-        if (r < 0) {
-                log_error_netdev(netdev, "Colud not append ifname to message: %s",
-                                 strerror(-r));
-                return r;
-        }
+                LIST_PREPEND(callbacks, netdev->callbacks, cb);
 
-        r = sd_rtnl_call_async(netdev->manager->rtnl, req, netdev_getlink_handler,
-                               netdev, 0, NULL);
-        if (r < 0) {
-                log_error_netdev(netdev,
-                               "Could not send rtnetlink message: %s", strerror(-r));
-                return r;
+                log_debug_netdev(netdev, "will enslave '%s', when reday",
+                                 link->ifname);
         }
 
         return 0;
 }
 
-static int netdev_create_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
-        NetDev *netdev = userdata;
-        int r;
-
-        assert(netdev->state != _NETDEV_STATE_INVALID);
+int netdev_set_ifindex(NetDev *netdev, sd_rtnl_message *message) {
+        uint16_t type;
+        const char *kind;
+        const char *received_kind;
+        const char *received_name;
+        int r, ifindex;
 
-        r = sd_rtnl_message_get_errno(m);
-        if (r == -EEXIST)
-                r = netdev_getlink(netdev);
+        assert(netdev);
+        assert(message);
 
+        r = sd_rtnl_message_get_type(message, &type);
         if (r < 0) {
-                log_warning_netdev(netdev, "netdev failed: %s", strerror(-r));
-                netdev_enter_failed(netdev);
-
-                return 1;
+                log_error_netdev(netdev, "Could not get rtnl message type");
+                return r;
         }
 
-        return 1;
-}
+        if (type != RTM_NEWLINK) {
+                log_error_netdev(netdev, "Can not set ifindex from unexpected rtnl message type");
+                return -EINVAL;
+        }
 
-static int netdev_create(NetDev *netdev, Link *link, sd_rtnl_message_handler_t callback) {
-        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
-        const char *kind;
-        int r;
+        r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
+        if (r < 0) {
+                log_error_netdev(netdev, "Could not get ifindex: %s", strerror(-r));
+                netdev_enter_failed(netdev);
+                return r;
+        } else if (ifindex <= 0) {
+                log_error_netdev(netdev, "Got invalid ifindex: %d", ifindex);
+                netdev_enter_failed(netdev);
+                return r;
+        }
 
-        assert(netdev);
-        assert(!(netdev->kind == NETDEV_KIND_VLAN || netdev->kind == NETDEV_KIND_MACVLAN) ||
-               (link && callback));
-        assert(netdev->name);
-        assert(netdev->manager);
-        assert(netdev->manager->rtnl);
+        if (netdev->ifindex > 0) {
+                if (netdev->ifindex != ifindex) {
+                        log_error_netdev(netdev, "Could not set ifindex to %d, already set to %d",
+                                         ifindex, netdev->ifindex);
+                        netdev_enter_failed(netdev);
+                        return -EEXIST;
+                } else
+                        /* ifindex already set to the same for this netdev */
+                        return 0;
+        }
 
-        r = sd_rtnl_message_new_link(netdev->manager->rtnl, &req, RTM_NEWLINK, 0);
+        r = sd_rtnl_message_read_string(message, IFLA_IFNAME, &received_name);
         if (r < 0) {
-                log_error_netdev(netdev,
-                                 "Could not allocate RTM_NEWLINK message: %s",
-                                 strerror(-r));
+                log_error_netdev(netdev, "Could not get IFNAME");
                 return r;
         }
 
-        if (link) {
-                r = sd_rtnl_message_append_u32(req, IFLA_LINK, link->ifindex);
-                if (r < 0) {
-                        log_error_netdev(netdev,
-                                         "Could not append IFLA_LINK attribute: %s",
-                                         strerror(-r));
-                        return r;
-                }
+        if (!streq(netdev->ifname, received_name)) {
+                log_error_netdev(netdev, "Received newlink with wrong IFNAME %s",
+                                 received_name);
+                netdev_enter_failed(netdev);
+                return r;
         }
 
-        r = sd_rtnl_message_append_string(req, IFLA_IFNAME, netdev->name);
+        r = sd_rtnl_message_enter_container(message, IFLA_LINKINFO);
         if (r < 0) {
-                log_error_netdev(netdev,
-                                 "Could not append IFLA_IFNAME attribute: %s",
-                                 strerror(-r));
+                log_error_netdev(netdev, "Could not get LINKINFO");
                 return r;
         }
 
-        r = sd_rtnl_message_open_container(req, IFLA_LINKINFO);
+        r = sd_rtnl_message_read_string(message, IFLA_INFO_KIND, &received_kind);
         if (r < 0) {
-                log_error_netdev(netdev,
-                                 "Could not open IFLA_LINKINFO container: %s",
-                                 strerror(-r));
+                log_error_netdev(netdev, "Could not get KIND");
                 return r;
         }
 
-        kind = netdev_kind_to_string(netdev->kind);
-        if (!kind) {
-                log_error_netdev(netdev, "Invalid kind");
-                return -EINVAL;
+        r = sd_rtnl_message_exit_container(message);
+        if (r < 0) {
+                log_error_netdev(netdev, "Could not exit container");
+                return r;
         }
 
-        r = sd_rtnl_message_append_string(req, IFLA_INFO_KIND, kind);
-        if (r < 0) {
+        if (netdev->kind == NETDEV_KIND_TAP)
+                /* the kernel does not distinguish between tun and tap */
+                kind = "tun";
+        else {
+                kind = netdev_kind_to_string(netdev->kind);
+                if (!kind) {
+                        log_error_netdev(netdev, "Could not get kind");
+                        netdev_enter_failed(netdev);
+                        return -EINVAL;
+                }
+        }
+
+        if (!streq(kind, received_kind)) {
                 log_error_netdev(netdev,
-                                 "Could not append IFLA_INFO_KIND attribute: %s",
-                                 strerror(-r));
+                                 "Received newlink with wrong KIND %s, "
+                                 "expected %s", received_kind, kind);
+                netdev_enter_failed(netdev);
                 return r;
         }
 
-        if (netdev->vlanid <= VLANID_MAX || netdev->macvlan_mode != _NETDEV_MACVLAN_MODE_INVALID) {
-                r = sd_rtnl_message_open_container(req, IFLA_INFO_DATA);
+        netdev->ifindex = ifindex;
+
+        log_debug_netdev(netdev, "netdev has index %d", netdev->ifindex);
+
+        netdev_enter_ready(netdev);
+
+        return 0;
+}
+
+#define HASH_KEY SD_ID128_MAKE(52,e1,45,bd,00,6f,29,96,21,c6,30,6d,83,71,04,48)
+
+int netdev_get_mac(const char *ifname, struct ether_addr **ret) {
+        _cleanup_free_ struct ether_addr *mac = NULL;
+        uint8_t result[8];
+        size_t l, sz;
+        uint8_t *v;
+        int r;
+
+        assert(ifname);
+        assert(ret);
+
+        mac = new0(struct ether_addr, 1);
+        if (!mac)
+                return -ENOMEM;
+
+        l = strlen(ifname);
+        sz = sizeof(sd_id128_t) + l;
+        v = alloca(sz);
+
+        /* fetch some persistent data unique to the machine */
+        r = sd_id128_get_machine((sd_id128_t*) v);
+        if (r < 0)
+                return r;
+
+        /* combine with some data unique (on this machine) to this
+         * netdev */
+        memcpy(v + sizeof(sd_id128_t), ifname, l);
+
+        /* Let's hash the host machine ID plus the container name. We
+         * use a fixed, but originally randomly created hash key here. */
+        siphash24(result, v, sz, HASH_KEY.bytes);
+
+        assert_cc(ETH_ALEN <= sizeof(result));
+        memcpy(mac->ether_addr_octet, result, ETH_ALEN);
+
+        /* see eth_random_addr in the kernel */
+        mac->ether_addr_octet[0] &= 0xfe;        /* clear multicast bit */
+        mac->ether_addr_octet[0] |= 0x02;        /* set local assignment bit (IEEE802) */
+
+        *ret = mac;
+        mac = NULL;
+
+        return 0;
+}
+
+static int netdev_create(NetDev *netdev, Link *link) {
+        int r;
+
+        assert(netdev);
+
+        /* create netdev */
+        if (NETDEV_VTABLE(netdev)->create) {
+                r = NETDEV_VTABLE(netdev)->create(netdev);
+                if (r < 0)
+                        return r;
+
+                log_debug_netdev(netdev, "created");
+        } else {
+                _cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
+
+                r = sd_rtnl_message_new_link(netdev->manager->rtnl, &m, RTM_NEWLINK, 0);
                 if (r < 0) {
                         log_error_netdev(netdev,
-                                         "Could not open IFLA_INFO_DATA container: %s",
+                                         "Could not allocate RTM_NEWLINK message: %s",
                                          strerror(-r));
                         return r;
                 }
 
-                if (netdev->vlanid <= VLANID_MAX) {
-                        r = sd_rtnl_message_append_u16(req, IFLA_VLAN_ID, netdev->vlanid);
+                r = sd_rtnl_message_append_string(m, IFLA_IFNAME, netdev->ifname);
+                if (r < 0) {
+                        log_error_netdev(netdev,
+                                         "Could not append IFLA_IFNAME, attribute: %s",
+                                         strerror(-r));
+                        return r;
+                }
+
+                if (netdev->mac) {
+                        r = sd_rtnl_message_append_ether_addr(m, IFLA_ADDRESS, netdev->mac);
                         if (r < 0) {
                                 log_error_netdev(netdev,
-                                                 "Could not append IFLA_VLAN_ID attribute: %s",
+                                                 "Could not append IFLA_ADDRESS attribute: %s",
+                                                 strerror(-r));
+                            return r;
+                        }
+                }
+
+                if (netdev->mtu) {
+                        r = sd_rtnl_message_append_u32(m, IFLA_MTU, netdev->mtu);
+                        if (r < 0) {
+                                log_error_netdev(netdev,
+                                                 "Could not append IFLA_MTU attribute: %s",
                                                  strerror(-r));
                                 return r;
                         }
                 }
 
-                if (netdev->macvlan_mode != _NETDEV_MACVLAN_MODE_INVALID) {
-                        r = sd_rtnl_message_append_u32(req, IFLA_MACVLAN_MODE, netdev->macvlan_mode);
+                if (link) {
+                        r = sd_rtnl_message_append_u32(m, IFLA_LINK, link->ifindex);
                         if (r < 0) {
                                 log_error_netdev(netdev,
-                                                 "Could not append IFLA_MACVLAN_MODE attribute: %s",
+                                                 "Colud not append IFLA_LINK attribute: %s",
                                                  strerror(-r));
                                 return r;
                         }
                 }
 
-                r = sd_rtnl_message_close_container(req);
+                r = sd_rtnl_message_open_container(m, IFLA_LINKINFO);
                 if (r < 0) {
                         log_error_netdev(netdev,
-                                         "Could not close IFLA_INFO_DATA container %s",
+                                         "Could not append IFLA_LINKINFO attribute: %s",
                                          strerror(-r));
                         return r;
                 }
-        }
 
-        r = sd_rtnl_message_close_container(req);
-        if (r < 0) {
-                log_error_netdev(netdev,
-                                 "Could not close IFLA_LINKINFO container %s",
-                                 strerror(-r));
-                return r;
-        }
-
-        if (link)
-                r = sd_rtnl_call_async(netdev->manager->rtnl, req, callback, link, 0, NULL);
-        else
-                r = sd_rtnl_call_async(netdev->manager->rtnl, req, &netdev_create_handler, netdev, 0, NULL);
-        if (r < 0) {
-                log_error_netdev(netdev,
-                                 "Could not send rtnetlink message: %s", strerror(-r));
-                return r;
-        }
+                r = sd_rtnl_message_open_container_union(m, IFLA_INFO_DATA,
+                                                         netdev_kind_to_string(netdev->kind));
+                if (r < 0) {
+                        log_error_netdev(netdev,
+                                         "Could not append IFLA_INFO_DATA attribute: %s",
+                                         strerror(-r));
+                        return r;
+                }
 
-        log_debug_netdev(netdev, "creating netdev");
+                if (NETDEV_VTABLE(netdev)->fill_message_create) {
+                        r = NETDEV_VTABLE(netdev)->fill_message_create(netdev, link, m);
+                        if (r < 0)
+                                return r;
+                }
 
-        netdev->state = NETDEV_STATE_CREATING;
+                r = sd_rtnl_message_close_container(m);
+                if (r < 0) {
+                        log_error_netdev(netdev,
+                                         "Could not append IFLA_LINKINFO attribute: %s",
+                                         strerror(-r));
+                        return r;
+                }
 
-        return 0;
-}
+                r = sd_rtnl_message_close_container(m);
+                if (r < 0) {
+                        log_error_netdev(netdev,
+                                         "Could not append IFLA_LINKINFO attribute: %s",
+                                         strerror(-r));
+                        return r;
+                }
 
-int netdev_enslave(NetDev *netdev, Link *link, sd_rtnl_message_handler_t callback) {
-        if (netdev->kind == NETDEV_KIND_VLAN || netdev->kind == NETDEV_KIND_MACVLAN)
-                return netdev_create(netdev, link, callback);
 
-        if (netdev->state == NETDEV_STATE_READY) {
-                netdev_enslave_ready(netdev, link, callback);
-        } else {
-                /* the netdev is not yet read, save this request for when it is*/
-                netdev_enslave_callback *cb;
+                r = sd_rtnl_call_async(netdev->manager->rtnl, m, netdev_create_handler, netdev, 0, NULL);
+                if (r < 0) {
+                        log_error_netdev(netdev,
+                                         "Could not send rtnetlink message: %s", strerror(-r));
+                        return r;
+                }
 
-                cb = new0(netdev_enslave_callback, 1);
-                if (!cb)
-                        return log_oom();
+                netdev_ref(netdev);
 
-                cb->callback = callback;
-                cb->link = link;
+                netdev->state = NETDEV_STATE_CREATING;
 
-                LIST_PREPEND(callbacks, netdev->callbacks, cb);
+                log_debug_netdev(netdev, "creating");
         }
 
         return 0;
 }
 
-int netdev_set_ifindex(NetDev *netdev, sd_rtnl_message *message) {
-        const char *kind;
-        char *received_kind;
-        int r, ifindex;
+/* the callback must be called, possibly after a timeout, as otherwise the Link will hang */
+int netdev_join(NetDev *netdev, Link *link, sd_rtnl_message_handler_t callback) {
+        int r;
 
         assert(netdev);
-        assert(ifindex > 0);
-
-        kind = netdev_kind_to_string(netdev->kind);
-        if (!kind)
-                log_error_netdev(netdev, "Could not get kind");
-
-        r = sd_rtnl_message_enter_container(message, IFLA_LINKINFO);
-        if (r < 0) {
-                log_error_netdev(netdev, "Could not get LINKINFO");
-                return r;
-        }
-
-        r = sd_rtnl_message_read_string(message, IFLA_INFO_KIND, &received_kind);
-        if (r < 0) {
-                log_error_netdev(netdev, "Could not get KIND");
-                return r;
-        }
+        assert(netdev->manager);
+        assert(netdev->manager->rtnl);
+        assert(NETDEV_VTABLE(netdev));
 
-        if (!streq(kind, received_kind)) {
-                log_error_netdev(netdev, "Received newlink with wrong KIND");
-                netdev_enter_failed(netdev);
-                return r;
-        }
+        switch (NETDEV_VTABLE(netdev)->create_type) {
+        case NETDEV_CREATE_MASTER:
+                r = netdev_enslave(netdev, link, callback);
+                if (r < 0)
+                        return r;
 
-        r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
-        if (r < 0) {
-                log_struct_netdev(LOG_ERR, netdev,
-                                "MESSAGE=%s: could not get ifindex: %s",
-                                netdev->name, strerror(-r),
-                                "ERRNO=%d", -r,
-                                NULL);
-                return r;
-        }
+                break;
+        case NETDEV_CREATE_STACKED:
+                r = netdev_create(netdev, link);
+                if (r < 0)
+                        return r;
 
-        if (netdev->ifindex > 0) {
-                if (netdev->ifindex == ifindex)
-                        return 0;
-                else
-                        return -EEXIST;
+                break;
+        default:
+                assert_not_reached("Can not join independent netdev");
         }
 
-        netdev->ifindex = ifindex;
-
-        netdev_enter_ready(netdev);
-
         return 0;
 }
 
 static int netdev_load_one(Manager *manager, const char *filename) {
-        _cleanup_netdev_free_ NetDev *netdev = NULL;
+        _cleanup_netdev_unref_ NetDev *netdev = NULL;
+        _cleanup_free_ NetDev *netdev_raw = NULL;
         _cleanup_fclose_ FILE *file = NULL;
         int r;
 
@@ -447,76 +605,106 @@ static int netdev_load_one(Manager *manager, const char *filename) {
                 if (errno == ENOENT)
                         return 0;
                 else
-                        return errno;
+                        return -errno;
         }
 
-        netdev = new0(NetDev, 1);
-        if (!netdev)
+        if (null_or_empty_fd(fileno(file))) {
+                log_debug("Skipping empty file: %s", filename);
+                return 0;
+        }
+
+        netdev_raw = new0(NetDev, 1);
+        if (!netdev_raw)
                 return log_oom();
 
-        netdev->manager = manager;
-        netdev->state = _NETDEV_STATE_INVALID;
-        netdev->kind = _NETDEV_KIND_INVALID;
-        netdev->macvlan_mode = _NETDEV_MACVLAN_MODE_INVALID;
-        netdev->vlanid = VLANID_MAX + 1;
+        netdev_raw->kind = _NETDEV_KIND_INVALID;
 
-        r = config_parse(NULL, filename, file, "Match\0NetDev\0VLAN\0MACVLAN\0",
-                         config_item_perf_lookup, (void*) network_netdev_gperf_lookup,
-                         false, false, netdev);
-        if (r < 0) {
-                log_warning("Could not parse config file %s: %s", filename, strerror(-r));
+        r = config_parse(NULL, filename, file,
+                         "Match\0NetDev\0",
+                         config_item_perf_lookup, network_netdev_gperf_lookup,
+                         true, false, true, netdev_raw);
+        if (r < 0)
                 return r;
-        }
 
-        if (netdev->kind == _NETDEV_KIND_INVALID) {
-                log_warning("NetDev without Kind configured in %s. Ignoring", filename);
-                return 0;
-        }
+        r = fseek(file, 0, SEEK_SET);
+        if (r < 0)
+                return -errno;
 
-        if (!netdev->name) {
-                log_warning("NetDev without Name configured in %s. Ignoring", filename);
+        /* skip out early if configuration does not match the environment */
+        if (net_match_config(NULL, NULL, NULL, NULL, NULL,
+                             netdev_raw->match_host, netdev_raw->match_virt,
+                             netdev_raw->match_kernel, netdev_raw->match_arch,
+                             NULL, NULL, NULL, NULL, NULL, NULL) <= 0)
                 return 0;
-        }
 
-        if (netdev->kind == NETDEV_KIND_VLAN && netdev->vlanid > VLANID_MAX) {
-                log_warning("VLAN without valid Id configured in %s. Ignoring", filename);
+        if (!NETDEV_VTABLE(netdev_raw)) {
+                log_warning("NetDev with invalid Kind configured in %s. Ignoring", filename);
                 return 0;
         }
 
-        if (netdev->kind != NETDEV_KIND_VLAN && netdev->vlanid <= VLANID_MAX) {
-                log_warning("VLAN Id configured for a %s in %s. Ignoring",
-                            netdev_kind_to_string(netdev->kind), filename);
+        if (!netdev_raw->ifname) {
+                log_warning("NetDev without Name configured in %s. Ignoring", filename);
                 return 0;
         }
 
-        if (netdev->kind != NETDEV_KIND_MACVLAN &&
-            netdev->macvlan_mode != _NETDEV_MACVLAN_MODE_INVALID) {
-                log_warning("MACVLAN Mode configured for a %s in %s. Ignoring",
-                            netdev_kind_to_string(netdev->kind), filename);
-                return 0;
+        netdev = malloc0(NETDEV_VTABLE(netdev_raw)->object_size);
+        if (!netdev)
+                return log_oom();
+
+        netdev->n_ref = 1;
+        netdev->manager = manager;
+        netdev->state = _NETDEV_STATE_INVALID;
+        netdev->kind = netdev_raw->kind;
+        netdev->ifname = netdev_raw->ifname;
+
+        if (NETDEV_VTABLE(netdev)->init)
+                NETDEV_VTABLE(netdev)->init(netdev);
+
+        r = config_parse(NULL, filename, file,
+                         NETDEV_VTABLE(netdev)->sections,
+                         config_item_perf_lookup, network_netdev_gperf_lookup,
+                         false, false, false, netdev);
+        if (r < 0)
+                return r;
+
+        /* verify configuration */
+        if (NETDEV_VTABLE(netdev)->config_verify) {
+                r = NETDEV_VTABLE(netdev)->config_verify(netdev, filename);
+                if (r < 0)
+                        return 0;
         }
 
         netdev->filename = strdup(filename);
         if (!netdev->filename)
                 return log_oom();
 
-        if (net_match_config(NULL, NULL, NULL, NULL, NULL,
-                             netdev->match_host, netdev->match_virt,
-                             netdev->match_kernel, netdev->match_arch,
-                             NULL, NULL, NULL, NULL, NULL, NULL) <= 0)
-                return 0;
+        if (!netdev->mac) {
+                r = netdev_get_mac(netdev->ifname, &netdev->mac);
+                if (r < 0) {
+                        log_error("Failed to generate predictable MAC address for %s",
+                                  netdev->ifname);
+                        return r;
+                }
+        }
 
-        r = hashmap_put(netdev->manager->netdevs, netdev->name, netdev);
+        r = hashmap_put(netdev->manager->netdevs, netdev->ifname, netdev);
         if (r < 0)
                 return r;
 
         LIST_HEAD_INIT(netdev->callbacks);
 
-        if (netdev->kind != NETDEV_KIND_VLAN &&
-            netdev->kind != NETDEV_KIND_MACVLAN) {
-                r = netdev_create(netdev, NULL, NULL);
+        log_debug_netdev(netdev, "loaded %s", netdev_kind_to_string(netdev->kind));
+
+        switch (NETDEV_VTABLE(netdev)->create_type) {
+        case NETDEV_CREATE_MASTER:
+        case NETDEV_CREATE_INDEPENDENT:
+                r = netdev_create(netdev, NULL);
                 if (r < 0)
                         return r;
+
+                break;
+        default:
+                break;
         }
 
         netdev = NULL;
@@ -532,7 +720,7 @@ int netdev_load(Manager *manager) {
         assert(manager);
 
         while ((netdev = hashmap_first(manager->netdevs)))
-                netdev_free(netdev);
+                netdev_unref(netdev);
 
         r = conf_files_list_strv(&files, ".netdev", NULL, network_dirs);
         if (r < 0) {