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>
29 #include "netlink-socket.h"
33 VLOG_DEFINE_THIS_MODULE(rtnetlink);
35 COVERAGE_DEFINE(rtnetlink_changed);
37 /* rtnetlink socket. */
38 static struct nl_sock *notify_sock;
40 /* All registered notifiers. */
41 static struct list all_notifiers = LIST_INITIALIZER(&all_notifiers);
43 static void rtnetlink_report_change(const struct nlmsghdr *,
44 const struct ifinfomsg *,
45 struct nlattr *attrs[]);
46 static void rtnetlink_report_notify_error(void);
48 /* Registers 'cb' to be called with auxiliary data 'aux' with network device
49 * change notifications. The notifier is stored in 'notifier', which the
50 * caller must not modify or free.
52 * This is probably not the function that you want. You should probably be
53 * using dpif_port_poll() or netdev_monitor_create(), which unlike this
54 * function are not Linux-specific.
56 * Returns 0 if successful, otherwise a positive errno value. */
58 rtnetlink_notifier_register(struct rtnetlink_notifier *notifier,
59 rtnetlink_notify_func *cb, void *aux)
62 int error = nl_sock_create(NETLINK_ROUTE, RTNLGRP_LINK, 0, 0,
65 VLOG_WARN("could not create rtnetlink socket: %s",
70 /* Catch up on notification work so that the new notifier won't
71 * receive any stale notifications. */
72 rtnetlink_notifier_run();
75 list_push_back(&all_notifiers, ¬ifier->node);
81 /* Cancels notification on 'notifier', which must have previously been
82 * registered with rtnetlink_notifier_register(). */
84 rtnetlink_notifier_unregister(struct rtnetlink_notifier *notifier)
86 list_remove(¬ifier->node);
87 if (list_is_empty(&all_notifiers)) {
88 nl_sock_destroy(notify_sock);
93 /* Calls all of the registered notifiers, passing along any as-yet-unreported
94 * netdev change events. */
96 rtnetlink_notifier_run(void)
98 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
105 /* Policy for RTNLGRP_LINK messages.
107 * There are *many* more fields in these messages, but currently we
108 * only care about these fields. */
109 static const struct nl_policy rtnetlink_policy[] = {
110 [IFLA_IFNAME] = { .type = NL_A_STRING, .optional = false },
111 [IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
114 struct nlattr *attrs[ARRAY_SIZE(rtnetlink_policy)];
118 error = nl_sock_recv(notify_sock, &buf, false);
120 if (nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
122 attrs, ARRAY_SIZE(rtnetlink_policy))) {
123 struct ifinfomsg *ifinfo;
125 ifinfo = (void *) ((char *) buf->data + NLMSG_HDRLEN);
126 rtnetlink_report_change(buf->data, ifinfo, attrs);
128 VLOG_WARN_RL(&rl, "received bad rtnl message");
129 rtnetlink_report_notify_error();
132 } else if (error == EAGAIN) {
135 if (error == ENOBUFS) {
136 VLOG_WARN_RL(&rl, "rtnetlink receive buffer overflowed");
138 VLOG_WARN_RL(&rl, "error reading rtnetlink socket: %s",
141 rtnetlink_report_notify_error();
146 /* Causes poll_block() to wake up when network device change notifications are
149 rtnetlink_notifier_wait(void)
152 nl_sock_wait(notify_sock, POLLIN);
157 rtnetlink_report_change(const struct nlmsghdr *nlmsg,
158 const struct ifinfomsg *ifinfo,
159 struct nlattr *attrs[])
161 struct rtnetlink_notifier *notifier;
162 struct rtnetlink_change change;
164 COVERAGE_INC(rtnetlink_changed);
166 change.nlmsg_type = nlmsg->nlmsg_type;
167 change.ifi_index = ifinfo->ifi_index;
168 change.ifname = nl_attr_get_string(attrs[IFLA_IFNAME]);
169 change.master_ifindex = (attrs[IFLA_MASTER]
170 ? nl_attr_get_u32(attrs[IFLA_MASTER]) : 0);
172 LIST_FOR_EACH (notifier, node, &all_notifiers) {
173 notifier->cb(&change, notifier->aux);
178 rtnetlink_report_notify_error(void)
180 struct rtnetlink_notifier *notifier;
182 LIST_FOR_EACH (notifier, node, &all_notifiers) {
183 notifier->cb(NULL, notifier->aux);