2 * Copyright (c) 2009, 2010 Nicira Networks.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
19 #include "rtnetlink.h"
22 #include <sys/socket.h>
23 #include <linux/rtnetlink.h>
32 VLOG_DEFINE_THIS_MODULE(rtnetlink);
34 COVERAGE_DEFINE(rtnetlink_changed);
36 /* rtnetlink socket. */
37 static struct nl_sock *notify_sock;
39 /* All registered notifiers. */
40 static struct list all_notifiers = LIST_INITIALIZER(&all_notifiers);
42 static void rtnetlink_report_change(const struct nlmsghdr *,
43 const struct ifinfomsg *,
44 struct nlattr *attrs[]);
45 static void rtnetlink_report_notify_error(void);
47 /* Registers 'cb' to be called with auxiliary data 'aux' with network device
48 * change notifications. The notifier is stored in 'notifier', which the
49 * caller must not modify or free.
51 * This is probably not the function that you want. You should probably be
52 * using dpif_port_poll() or netdev_monitor_create(), which unlike this
53 * function are not Linux-specific.
55 * Returns 0 if successful, otherwise a positive errno value. */
57 rtnetlink_notifier_register(struct rtnetlink_notifier *notifier,
58 rtnetlink_notify_func *cb, void *aux)
61 int error = nl_sock_create(NETLINK_ROUTE, RTNLGRP_LINK, 0, 0,
64 VLOG_WARN("could not create rtnetlink socket: %s",
69 /* Catch up on notification work so that the new notifier won't
70 * receive any stale notifications. */
71 rtnetlink_notifier_run();
74 list_push_back(&all_notifiers, ¬ifier->node);
80 /* Cancels notification on 'notifier', which must have previously been
81 * registered with rtnetlink_notifier_register(). */
83 rtnetlink_notifier_unregister(struct rtnetlink_notifier *notifier)
85 list_remove(¬ifier->node);
86 if (list_is_empty(&all_notifiers)) {
87 nl_sock_destroy(notify_sock);
92 /* Calls all of the registered notifiers, passing along any as-yet-unreported
93 * netdev change events. */
95 rtnetlink_notifier_run(void)
97 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
104 /* Policy for RTNLGRP_LINK messages.
106 * There are *many* more fields in these messages, but currently we
107 * only care about these fields. */
108 static const struct nl_policy rtnetlink_policy[] = {
109 [IFLA_IFNAME] = { .type = NL_A_STRING, .optional = false },
110 [IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
113 struct nlattr *attrs[ARRAY_SIZE(rtnetlink_policy)];
117 error = nl_sock_recv(notify_sock, &buf, false);
119 if (nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
121 attrs, ARRAY_SIZE(rtnetlink_policy))) {
122 struct ifinfomsg *ifinfo;
124 ifinfo = (void *) ((char *) buf->data + NLMSG_HDRLEN);
125 rtnetlink_report_change(buf->data, ifinfo, attrs);
127 VLOG_WARN_RL(&rl, "received bad rtnl message");
128 rtnetlink_report_notify_error();
131 } else if (error == EAGAIN) {
134 if (error == ENOBUFS) {
135 VLOG_WARN_RL(&rl, "rtnetlink receive buffer overflowed");
137 VLOG_WARN_RL(&rl, "error reading rtnetlink socket: %s",
140 rtnetlink_report_notify_error();
145 /* Causes poll_block() to wake up when network device change notifications are
148 rtnetlink_notifier_wait(void)
151 nl_sock_wait(notify_sock, POLLIN);
156 rtnetlink_report_change(const struct nlmsghdr *nlmsg,
157 const struct ifinfomsg *ifinfo,
158 struct nlattr *attrs[])
160 struct rtnetlink_notifier *notifier;
161 struct rtnetlink_change change;
163 COVERAGE_INC(rtnetlink_changed);
165 change.nlmsg_type = nlmsg->nlmsg_type;
166 change.ifi_index = ifinfo->ifi_index;
167 change.ifname = nl_attr_get_string(attrs[IFLA_IFNAME]);
168 change.master_ifindex = (attrs[IFLA_MASTER]
169 ? nl_attr_get_u32(attrs[IFLA_MASTER]) : 0);
171 LIST_FOR_EACH (notifier, node, &all_notifiers) {
172 notifier->cb(&change, notifier->aux);
177 rtnetlink_report_notify_error(void)
179 struct rtnetlink_notifier *notifier;
181 LIST_FOR_EACH (notifier, node, &all_notifiers) {
182 notifier->cb(NULL, notifier->aux);