2 * Copyright (c) 2009, 2010, 2011 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"
27 #include "netlink-socket.h"
31 VLOG_DEFINE_THIS_MODULE(rtnetlink);
33 COVERAGE_DEFINE(rtnetlink_changed);
35 static void rtnetlink_report(struct rtnetlink *rtn, void *change);
38 struct nl_sock *notify_sock; /* Rtnetlink socket. */
39 struct list all_notifiers; /* All rtnetlink notifiers. */
41 /* Passed in by rtnetlink_create(). */
42 int multicast_group; /* Multicast group we listen on. */
43 rtnetlink_parse_func *parse; /* Message parsing function. */
44 void *change; /* Change passed to parse. */
47 /* Creates an rtnetlink handle which may be used to manage change
48 * notifications. The created handle will listen for rtnetlink messages on
49 * 'multicast_group'. Incoming messages will be parsed with 'parse' which will
50 * be passed 'change' as an argument. */
52 rtnetlink_create(int multicast_group, rtnetlink_parse_func *parse,
55 struct rtnetlink *rtn;
57 rtn = xzalloc(sizeof *rtn);
59 rtn->multicast_group = multicast_group;
63 list_init(&rtn->all_notifiers);
67 /* Destroys 'rtn' by freeing any memory it has reserved and closing any sockets
70 rtnetlink_destroy(struct rtnetlink *rtn)
73 nl_sock_destroy(rtn->notify_sock);
78 /* Registers 'cb' to be called with auxiliary data 'aux' with change
79 * notifications. The notifier is stored in 'notifier', which the caller must
82 * This is probably not the function you want. You should probably be using
83 * message specific notifiers like rtnetlink_link_notifier_register().
85 * Returns 0 if successful, otherwise a positive errno value. */
87 rtnetlink_notifier_register(struct rtnetlink *rtn,
88 struct rtnetlink_notifier *notifier,
89 rtnetlink_notify_func *cb, void *aux)
91 if (!rtn->notify_sock) {
95 error = nl_sock_create(NETLINK_ROUTE, &sock);
97 error = nl_sock_join_mcgroup(sock, rtn->multicast_group);
100 nl_sock_destroy(sock);
101 VLOG_WARN("could not create rtnetlink socket: %s",
105 rtn->notify_sock = sock;
107 /* Catch up on notification work so that the new notifier won't
108 * receive any stale notifications. */
109 rtnetlink_notifier_run(rtn);
112 list_push_back(&rtn->all_notifiers, ¬ifier->node);
118 /* Cancels notification on 'notifier', which must have previously been
119 * registered with rtnetlink_notifier_register(). */
121 rtnetlink_notifier_unregister(struct rtnetlink *rtn,
122 struct rtnetlink_notifier *notifier)
124 list_remove(¬ifier->node);
125 if (list_is_empty(&rtn->all_notifiers)) {
126 nl_sock_destroy(rtn->notify_sock);
127 rtn->notify_sock = NULL;
131 /* Calls all of the registered notifiers, passing along any as-yet-unreported
134 rtnetlink_notifier_run(struct rtnetlink *rtn)
136 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
138 if (!rtn->notify_sock) {
146 error = nl_sock_recv(rtn->notify_sock, &buf, false);
148 if (rtn->parse(buf, rtn->change)) {
149 rtnetlink_report(rtn, rtn->change);
151 VLOG_WARN_RL(&rl, "received bad rtnl message");
152 rtnetlink_report(rtn, NULL);
155 } else if (error == EAGAIN) {
158 if (error == ENOBUFS) {
159 VLOG_WARN_RL(&rl, "rtnetlink receive buffer overflowed");
161 VLOG_WARN_RL(&rl, "error reading rtnetlink socket: %s",
164 rtnetlink_report(rtn, NULL);
169 /* Causes poll_block() to wake up when change notifications are ready. */
171 rtnetlink_notifier_wait(struct rtnetlink *rtn)
173 if (rtn->notify_sock) {
174 nl_sock_wait(rtn->notify_sock, POLLIN);
179 rtnetlink_report(struct rtnetlink *rtn, void *change)
181 struct rtnetlink_notifier *notifier;
184 COVERAGE_INC(rtnetlink_changed);
187 LIST_FOR_EACH (notifier, node, &rtn->all_notifiers) {
188 notifier->cb(change, notifier->aux);