2 * Copyright (c) 2009 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>
31 #define THIS_MODULE VLM_rtnetlink
34 /* rtnetlink socket. */
35 static struct nl_sock
*notify_sock
;
37 /* All registered notifiers. */
38 static struct list all_notifiers
= LIST_INITIALIZER(&all_notifiers
);
40 static void rtnetlink_report_change(const struct nlmsghdr
*,
41 const struct ifinfomsg
*,
42 struct nlattr
*attrs
[]);
43 static void rtnetlink_report_notify_error(void);
45 /* Registers 'cb' to be called with auxiliary data 'aux' with network device
46 * change notifications. The notifier is stored in 'notifier', which the
47 * caller must not modify or free.
49 * This is probably not the function that you want. You should probably be
50 * using dpif_port_poll() or netdev_monitor_create(), which unlike this
51 * function are not Linux-specific.
53 * Returns 0 if successful, otherwise a positive errno value. */
55 rtnetlink_notifier_register(struct rtnetlink_notifier
*notifier
,
56 rtnetlink_notify_func
*cb
, void *aux
)
59 int error
= nl_sock_create(NETLINK_ROUTE
, RTNLGRP_LINK
, 0, 0,
62 VLOG_WARN("could not create rtnetlink socket: %s",
67 /* Catch up on notification work so that the new notifier won't
68 * receive any stale notifications. */
69 rtnetlink_notifier_run();
72 list_push_back(&all_notifiers
, ¬ifier
->node
);
78 /* Cancels notification on 'notifier', which must have previously been
79 * registered with lxnetdev_notifier_register(). */
81 rtnetlink_notifier_unregister(struct rtnetlink_notifier
*notifier
)
83 list_remove(¬ifier
->node
);
84 if (list_is_empty(&all_notifiers
)) {
85 nl_sock_destroy(notify_sock
);
90 /* Calls all of the registered notifiers, passing along any as-yet-unreported
91 * netdev change events. */
93 rtnetlink_notifier_run(void)
95 static struct vlog_rate_limit rl
= VLOG_RATE_LIMIT_INIT(1, 5);
102 /* Policy for RTNLGRP_LINK messages.
104 * There are *many* more fields in these messages, but currently we
105 * only care about these fields. */
106 static const struct nl_policy rtnetlink_policy
[] = {
107 [IFLA_IFNAME
] = { .type
= NL_A_STRING
, .optional
= false },
108 [IFLA_MASTER
] = { .type
= NL_A_U32
, .optional
= true },
111 struct nlattr
*attrs
[ARRAY_SIZE(rtnetlink_policy
)];
115 error
= nl_sock_recv(notify_sock
, &buf
, false);
117 if (nl_policy_parse(buf
, NLMSG_HDRLEN
+ sizeof(struct ifinfomsg
),
119 attrs
, ARRAY_SIZE(rtnetlink_policy
))) {
120 struct ifinfomsg
*ifinfo
;
122 ifinfo
= (void *) ((char *) buf
->data
+ NLMSG_HDRLEN
);
123 rtnetlink_report_change(buf
->data
, ifinfo
, attrs
);
125 VLOG_WARN_RL(&rl
, "received bad rtnl message");
126 rtnetlink_report_notify_error();
129 } else if (error
== EAGAIN
) {
132 if (error
== ENOBUFS
) {
133 VLOG_WARN_RL(&rl
, "rtnetlink receive buffer overflowed");
135 VLOG_WARN_RL(&rl
, "error reading rtnetlink socket: %s",
138 rtnetlink_report_notify_error();
143 /* Causes poll_block() to wake up when network device change notifications are
146 rtnetlink_notifier_wait(void)
149 nl_sock_wait(notify_sock
, POLLIN
);
154 rtnetlink_report_change(const struct nlmsghdr
*nlmsg
,
155 const struct ifinfomsg
*ifinfo
,
156 struct nlattr
*attrs
[])
158 struct rtnetlink_notifier
*notifier
;
159 struct rtnetlink_change change
;
161 COVERAGE_INC(rtnetlink_changed
);
163 change
.nlmsg_type
= nlmsg
->nlmsg_type
;
164 change
.ifi_index
= ifinfo
->ifi_index
;
165 change
.ifname
= nl_attr_get_string(attrs
[IFLA_IFNAME
]);
166 change
.master_ifindex
= (attrs
[IFLA_MASTER
]
167 ? nl_attr_get_u32(attrs
[IFLA_MASTER
]) : 0);
169 LIST_FOR_EACH (notifier
, struct rtnetlink_notifier
, node
,
171 notifier
->cb(&change
, notifier
->aux
);
176 rtnetlink_report_notify_error(void)
178 struct rtnetlink_notifier
*notifier
;
180 LIST_FOR_EACH (notifier
, struct rtnetlink_notifier
, node
,
182 notifier
->cb(NULL
, notifier
->aux
);