networkd: add bridge support

A bridge is specified in a .netdev file with a section [Bridge]
and at least the entry Name=.

A link may be joined to a bridge if the .network applied to it has
a Bridge= entry giving the name of the bridge in its [Network] section.

We eagerly create all bridges on startup, and links are added to
bridges as soon as they both appear.

1 files changed, 321 insertions, 0 deletions

diff --git a/src/network/networkd-bridge.c b/src/network/networkd-bridge.c
new file mode 100644
index 0000000000..371c093ca1
--- /dev/null
+++ b/src/network/networkd-bridge.c
@@ -0,0 +1,321 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Tom Gundersen <teg@jklm.no>
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "networkd.h"
+#include "net-util.h"
+#include "path-util.h"
+#include "conf-files.h"
+#include "conf-parser.h"
+#include "list.h"
+
+void bridge_free(Bridge *bridge) {
+        bridge_join_callback *callback;
+
+        if (!bridge)
+                return;
+
+        while ((callback = bridge->callbacks)) {
+                LIST_REMOVE(callbacks, bridge->callbacks, callback);
+                free(callback);
+        }
+
+        if (bridge->name)
+                hashmap_remove(bridge->manager->bridges, bridge->name);
+
+        free(bridge->filename);
+
+        free(bridge->description);
+        free(bridge->name);
+
+        free(bridge);
+}
+
+int bridge_get(Manager *manager, const char *name, Bridge **ret) {
+        Bridge *bridge;
+
+        assert(manager);
+        assert(name);
+        assert(ret);
+
+        if (manager_should_reload(manager))
+                manager_load_config(manager);
+
+        bridge = hashmap_get(manager->bridges, name);
+        if (!bridge) {
+                *ret = NULL;
+                return -ENOENT;
+        }
+
+        *ret = bridge;
+
+        return 0;
+}
+
+static int bridge_enter_failed(Bridge *bridge) {
+        bridge->state = BRIDGE_STATE_FAILED;
+
+        return 0;
+}
+
+static int bridge_join_ready(Bridge *bridge, Link* link, sd_rtnl_message_handler_t callback) {
+        _cleanup_sd_rtnl_message_unref_ sd_rtnl_message *req = NULL;
+        int r;
+
+        assert(bridge);
+        assert(bridge->state == BRIDGE_STATE_READY);
+        assert(link);
+        assert(callback);
+
+        r = sd_rtnl_message_link_new(RTM_SETLINK, link->ifindex, 0, 0, &req);
+        if (r < 0) {
+                log_error("Could not allocate RTM_SETLINK message: %s",
+                          strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_append(req, IFLA_MASTER, &bridge->link->ifindex);
+        if (r < 0) {
+                log_error("Could not append IFLA_MASTER attribute: %s",
+                          strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_call_async(bridge->manager->rtnl, req, callback, link, 0, NULL);
+        if (r < 0) {
+                log_error("Could not send rtnetlink message: %s", strerror(-r));
+                return r;
+        }
+
+        return 0;
+}
+
+static int bridge_enter_ready(Bridge *bridge) {
+        bridge_join_callback *callback;
+
+        bridge->state = BRIDGE_STATE_READY;
+
+        log_info("Bridge '%s' ready", bridge->name);
+
+        LIST_FOREACH(callbacks, callback, bridge->callbacks) {
+                /* join the links that were attempted to be joined befor the
+                 * link was ready */
+                bridge_join_ready(bridge, callback->link, callback->callback);
+        }
+
+        return 0;
+}
+
+static int bridge_create_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
+        Bridge *bridge = userdata;
+        int r;
+
+        assert(bridge->state == BRIDGE_STATE_CREATING);
+
+        r = sd_rtnl_message_get_errno(m);
+        if (r < 0) {
+                log_warning("Bridge '%s' failed: %s", bridge->name, strerror(-r));
+                return bridge_enter_failed(bridge);
+        }
+
+        if (bridge->link)
+                return bridge_enter_ready(bridge);
+
+        bridge->state = BRIDGE_STATE_CREATED;
+
+        return 0;
+}
+
+static int bridge_create(Bridge *bridge) {
+        _cleanup_sd_rtnl_message_unref_ sd_rtnl_message *req = NULL;
+        int r;
+
+        assert(bridge);
+        assert(bridge->state == _BRIDGE_STATE_INVALID);
+        assert(bridge->name);
+        assert(bridge->manager);
+        assert(bridge->manager->rtnl);
+
+        r = sd_rtnl_message_link_new(RTM_NEWLINK, 0, 0, 0, &req);
+        if (r < 0) {
+                log_error("Could not allocate RTM_NEWLINK message: %s",
+                          strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_append(req, IFLA_IFNAME, bridge->name);
+        if (r < 0) {
+                log_error("Could not append IFLA_IFNAME attribute: %s",
+                          strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_open_container(req, IFLA_LINKINFO);
+        if (r < 0) {
+                log_error("Colud not open IFLA_LINKINFO container: %s",
+                          strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_append(req, IFLA_INFO_KIND, "bridge");
+        if (r < 0) {
+                log_error("Could not append IFLA_INFO_KIND attribute: %s",
+                          strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_close_container(req);
+        if (r < 0) {
+                log_error("Could not close IFLA_LINKINFO container %s",
+                          strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_call_async(bridge->manager->rtnl, req, &bridge_create_handler, bridge, 0, NULL);
+        if (r < 0) {
+                log_error("Could not send rtnetlink message: %s", strerror(-r));
+                return r;
+        }
+
+        log_info("Creating bridge '%s'", bridge->name);
+
+        bridge->state = BRIDGE_STATE_CREATING;
+
+        return 0;
+}
+
+int bridge_join(Bridge *bridge, Link *link, sd_rtnl_message_handler_t callback) {
+        _cleanup_sd_rtnl_message_unref_ sd_rtnl_message *req = NULL;
+
+        if (bridge->state == BRIDGE_STATE_READY) {
+                bridge_join_ready(bridge, link, callback);
+        } else {
+                /* the bridge is not yet read, save this request for when it is*/
+                bridge_join_callback *cb;
+
+                cb = new0(bridge_join_callback, 1);
+                if (!cb)
+                        return log_oom();
+
+                cb->callback = callback;
+                cb->link = link;
+
+                LIST_PREPEND(callbacks, bridge->callbacks, cb);
+        }
+
+        return 0;
+}
+
+int bridge_set_link(Manager *m, Link *link) {
+        Bridge *bridge;
+
+        bridge = hashmap_get(m->bridges, link->ifname);
+        if (!bridge)
+                return -ENOENT;
+
+        if (bridge->link && bridge->link != link)
+                return -EEXIST;
+
+        bridge->link = link;
+
+        if (bridge->state == BRIDGE_STATE_CREATED)
+                bridge_enter_ready(bridge);
+
+        return 0;
+}
+
+static int bridge_load_one(Manager *manager, const char *filename) {
+        _cleanup_bridge_free_ Bridge *bridge = NULL;
+        _cleanup_fclose_ FILE *file = NULL;
+        int r;
+
+        file = fopen(filename, "re");
+        if (!file) {
+                if (errno == ENOENT)
+                        return 0;
+                else
+                        return errno;
+        }
+
+        bridge = new0(Bridge, 1);
+        if (!bridge)
+                return log_oom();
+
+        bridge->manager = manager;
+        bridge->state = _BRIDGE_STATE_INVALID;
+
+        r = config_parse(NULL, filename, file, "Bridge\0", config_item_perf_lookup,
+                        (void*) network_gperf_lookup, false, false, bridge);
+        if (r < 0) {
+                log_warning("Could not parse config file %s: %s", filename, strerror(-r));
+                return r;
+        } else
+                log_debug("Parsed configuration file %s", filename);
+
+        if (!bridge->name) {
+                log_warning("Bridge without Name configured in %s. Ignoring", filename);
+                return 0;
+        }
+
+        bridge->filename = strdup(filename);
+        if (!bridge->filename)
+                return log_oom();
+
+        r = hashmap_put(bridge->manager->bridges, bridge->name, bridge);
+        if (r < 0)
+                return r;
+
+        LIST_HEAD_INIT(bridge->callbacks);
+
+        r = bridge_create(bridge);
+        if (r < 0)
+                return r;
+
+        bridge = NULL;
+
+        return 0;
+}
+
+int bridge_load(Manager *manager) {
+        Bridge *bridge;
+        char **files, **f;
+        int r;
+
+        assert(manager);
+
+        while ((bridge = hashmap_first(manager->bridges)))
+                bridge_free(bridge);
+
+        r = conf_files_list_strv(&files, ".netdev", NULL, (const char **)manager->network_dirs);
+        if (r < 0) {
+                log_error("Failed to enumerate netdev files: %s", strerror(-r));
+                return r;
+        }
+
+        STRV_FOREACH_BACKWARDS(f, files) {
+                r = bridge_load_one(manager, *f);
+                if (r < 0)
+                        return r;
+        }
+
+        strv_free(files);
+
+        return 0;
+}