+/*
+ * Copyright (c) 2009 Nicira Networks.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+
+#include "netdev-linux.h"
+
+#include <errno.h>
+#include <sys/socket.h>
+#include <linux/rtnetlink.h>
+#include <poll.h>
+
+#include "coverage.h"
+#include "netlink.h"
+#include "ofpbuf.h"
+
+#define THIS_MODULE VLM_netdev_linux
+#include "vlog.h"
+
+/* rtnetlink socket. */
+static struct nl_sock *rtnl_sock;
+
+/* All registered notifiers. */
+static struct list all_notifiers = LIST_INITIALIZER(&all_notifiers);
+
+static void linux_netdev_report_change(const struct nlmsghdr *,
+ const struct ifinfomsg *,
+ struct nlattr *attrs[]);
+static void linux_netdev_report_notify_error(int error);
+
+int
+linux_netdev_notifier_register(struct linux_netdev_notifier *notifier,
+ linux_netdev_notify_func *cb, void *aux)
+{
+ if (!rtnl_sock) {
+ int error = nl_sock_create(NETLINK_ROUTE, RTNLGRP_LINK, 0, 0,
+ &rtnl_sock);
+ if (error) {
+ VLOG_WARN("could not create rtnetlink socket: %s",
+ strerror(error));
+ return error;
+ }
+ } else {
+ /* Catch up on notification work so that the new notifier won't
+ * receive any stale notifications. */
+ linux_netdev_notifier_run();
+ }
+
+ list_push_back(&all_notifiers, ¬ifier->node);
+ notifier->error = 0;
+ notifier->cb = cb;
+ notifier->aux = aux;
+ return 0;
+}
+
+void
+linux_netdev_notifier_unregister(struct linux_netdev_notifier *notifier)
+{
+ list_remove(¬ifier->node);
+ if (list_is_empty(&all_notifiers)) {
+ nl_sock_destroy(rtnl_sock);
+ rtnl_sock = NULL;
+ }
+}
+
+int
+linux_netdev_notifier_get_error(struct linux_netdev_notifier *notifier)
+{
+ int error = notifier->error;
+ notifier->error = 0;
+ return error;
+}
+
+int
+linux_netdev_notifier_peek_error(const struct linux_netdev_notifier *notifier)
+{
+ return notifier->error;
+}
+
+static const struct nl_policy rtnlgrp_link_policy[] = {
+ [IFLA_IFNAME] = { .type = NL_A_STRING },
+ [IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
+};
+
+void
+linux_netdev_notifier_run(void)
+{
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
+
+ if (!rtnl_sock) {
+ return;
+ }
+
+ for (;;) {
+ struct nlattr *attrs[ARRAY_SIZE(rtnlgrp_link_policy)];
+ struct ofpbuf *buf;
+ int error;
+
+ error = nl_sock_recv(rtnl_sock, &buf, false);
+ if (!error) {
+ if (nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
+ rtnlgrp_link_policy,
+ attrs, ARRAY_SIZE(rtnlgrp_link_policy))) {
+ struct ifinfomsg *ifinfo;
+
+ ifinfo = (void *) ((char *) buf->data + NLMSG_HDRLEN);
+ linux_netdev_report_change(buf->data, ifinfo, attrs);
+ } else {
+ VLOG_WARN_RL(&rl, "received bad rtnl message");
+ linux_netdev_report_notify_error(ENOBUFS);
+ }
+ ofpbuf_delete(buf);
+ } else if (error == EAGAIN) {
+ return;
+ } else {
+ if (error == ENOBUFS) {
+ VLOG_WARN_RL(&rl, "rtnetlink receive buffer overflowed");
+ } else {
+ VLOG_WARN_RL(&rl, "error reading rtnetlink socket: %s",
+ strerror(error));
+ }
+ linux_netdev_report_notify_error(error);
+ }
+ }
+}
+
+void
+linux_netdev_notifier_wait(void)
+{
+ if (rtnl_sock) {
+ nl_sock_wait(rtnl_sock, POLLIN);
+ }
+}
+
+static void
+linux_netdev_report_change(const struct nlmsghdr *nlmsg,
+ const struct ifinfomsg *ifinfo,
+ struct nlattr *attrs[])
+{
+ struct linux_netdev_notifier *notifier;
+ struct linux_netdev_change change;
+
+ COVERAGE_INC(linux_netdev_changed);
+
+ change.nlmsg_type = nlmsg->nlmsg_type;
+ change.ifi_index = ifinfo->ifi_index;
+ change.ifname = nl_attr_get_string(attrs[IFLA_IFNAME]);
+ change.master_ifindex = (attrs[IFLA_MASTER]
+ ? nl_attr_get_u32(attrs[IFLA_MASTER]) : 0);
+
+ LIST_FOR_EACH (notifier, struct linux_netdev_notifier, node,
+ &all_notifiers) {
+ if (!notifier->error) {
+ notifier->cb(&change, notifier->aux);
+ }
+ }
+}
+
+static void
+linux_netdev_report_notify_error(int error)
+{
+ struct linux_netdev_notifier *notifier;
+
+ LIST_FOR_EACH (notifier, struct linux_netdev_notifier, node,
+ &all_notifiers) {
+ if (error != ENOBUFS || !notifier->error) {
+ notifier->error = error;
+ }
+ }
+}